A heated liquid sampling probe for an automated sampling apparatus includes a sampling tube for drawing up a volume of liquid. The tube is connectable to an automated sampling apparatus including a chassis. A capacitance exists between the sampling tube and the chassis. An electrical heater is arranged for heating the tube and a volume of liquid contained therein. The electrical heater increases the capacitance between the tube and the chassis. A capacitance lowering mechanism is provided for lowering the increase in capacitance due to the heater.

The present invention relates to an automated sample handling system having a heated liquid sampling probe.
Automated sample handling systems are known which automatically dispense fluid samples, such as blood plasma and reagents, into the reaction well of a cuvette. Such instruments are useful in the field of biochemical analysis for measuring blood clotting times and for automatically carrying out other bioassays.
An automated sample handling system of this type is described in U.S. patent application Ser. No. 07/443,951. In this system a temperature controlled housing is provided for storing the fluid samples and reagents at a relatively cool temperature for preventing degradation of the samples and reagents prior to sample analysis. The temperature controlled housing typically maintains the fluid samples and reagents at a temperature of 4.degree. C. The actual analyses are generally carried-out at 37.degree. C. (98.6.degree. F.), standard human body temperature. Accordingly, it is necessary to heat up the fluid sample and reagents to 37.degree. C. prior to analysis.
In the above-described sample handling system, a temperature-controlled linear track on which the cuvettes are transported is sufficient to bring the fluid samples to the reaction temperature. However, it has been found necessary to pre-heat the reagents while in the sampling tube prior to being dispensed in the reaction well of a cuvette in order to assure the reaction volume is at the proper temperature at the proper time.
In order to achieve the desired heating of a volume of liquid in the liquid sampling tube, it has been attempted to use an electric heating element disposed directly on the tube. These attempts have failed because previous applications of electrical heating elements placed directly against the sampling tube have caused malfunctions in the capacitive touch liquid level sensing devices commonly used with automated liquid sample handling systems.
One of those known attempts to heat the sampling tube and the aspirated liquid therein by an electric heater element was abandoned owing to unsatisfactorily results. The results were unsatisfactory because the electrical heater increased the capacitance developed between the liquid sampling tube and the instrument chassis to such a large extent that the capacitive touch liquid level sensing device or, simply, the capacitance measuring device, was unable to accurately detect the change in capacitance when the sampling tube contacted the surface of the liquid to be sampled. Thus, for example, a robotic arm controlled by information from the capacitance measuring device failed to stop lowering a sampling tube into a liquid sample as the capacitance measuring device was unable to detect the surface of the liquid to be sampled and, hence, was unable to send such information to a central controller for operating the robotic arm.
To understand why those known attempts at using an electrical heating element disposed directly on the liquid sampling tube failed, a discussion of how the capacitance measuring device functions, as applied in this environment, follows.
Basically, in this environment the capacitive liquid level sensor works on the principle of measuring the change in capacitance between the sampling tube and the chassis of the instrument. The sampling tube forms one "plate" and the chassis forms the other "plate" of the capacitor. Atmospheric air is the dielectric. When the liquid sampling tube touches the surface of the liquid to be sampled, the plate of the capacitor that is formed by the sampling tube is now effectively larger because of its contact with the liquid sample. This increases the capacitance between the sampling tube and the chassis that is detected by the liquid level sensing device.
This change in capacitance indicates that the liquid sampling tube has contacted the surface of the fluid sample and this information is sent to the central controller of the instrument for sending control signals to the robotic arm. The control signals tell the robotic arm how much further past the detected surface to lower the fluid sampling tube into the liquid sample for aspirating a predetermined amount of fluid to be analyzed. A known capacitive touch liquid level sensor is supplied by CAVRO Scientific Instruments, Inc., Sunnyvale, Calif., and marketed as Model No. 721014B. The control signals for controlling the robotic arm are received and sent by the central controller of the instrument in a manner well understood by those skilled in the art.
A further attempt to solve the problem of heating a sampling tube without adversely affecting the capacitive touch liquid level sensor is known. In this attempt a water jacket was disposed on the liquid sampling tube for circulating warm fluid to heat up the aspirated sample. However, such a water jacket proved to be unsatisfactory owing to its being bulky, and, hence, not usable in the desired application with an automated liquid sampling apparatus.

Heated liquid sampling probe for an automated sampling apparatus


The present invention enables identification of events such as target. From training target event data the present a very large number of clusters are formed for each class based on Euclidean distance using a repetitive k-means clustering process. Features from each cluster are identified by extracting out their dominant eigenvectors. Once all of the dominant eigenvectors have been identified, they define the relevant space of the cluster. New target event data is compared to each cluster by projecting it onto the relevant and noise spaces. The more the data lies within the relevant space and the less it lies within the noise space the more similar the data is to a cluster. The new target event data is then classified based on the training target event data.

Classification is an important field of study in many disciplines. Human beings do this naturally all the time; medical doctors use their skills to identify diseases, inspection line-workers use them to identify defective manufactured parts, police use them to find wanted criminals, etc. Since machines do not tire, can reliably provide the same output for the same given set of inputs and can readily be reproduced, it would be extremely desirable to develop one that could learn how to classify as well or better than the best human classifiers.
The literature is filled with examples where machines receive data and attempt to classify it in some way. Typically, this data can be represented in the form of a multidimensional vector defined within some hyperspace, wherein each dimension of the vector can be viewed as a feature of the data. Therefore by using machines, one can view many problems as processing an unknown data vector in some way that produces an output, which correctly associates it with a known class. Exemplar based machine learning techniques tackle these problems by learning to distinguish among classes through representative training examples. These techniques can be supervised or unsupervised, classifications can be generalized or specific instances can be retained for comparison purposes, and they can be trained incrementally or in a batch process. Several popular algorithms employing these techniques in various ways have been developed and published in the literature. In general, they result in an algorithm that attempts to classify an unknown data vector after learning from training examples.
Human brains continually classify the detections made by their sensors. Seeing and recognizing someone's face, listening and understanding a spoken word, smelling a lemon, feeling the presence of a liquid and tasting an apple are simple examples of how humans classify the detections made by their sensors. In essence, a person receives data from one or more than one sensor and then classifies the object sensed based on these detections. Of course, one of these classifications is "don't know".
The accuracy under which classifications are made largely depends on the level of experience that the person has that is making the classification. The more experience a person has sensing various objects, the more likely they are to accurately classify an unknown object into one of their categories. Their known categories are generally formed based on what they have initially learned from a teacher (supervised learning) or have independently established based on objects they had discovered (unsupervised learning).
The teacher's function is to provide the student with accurate concrete examples of a particular class. The more examples the student is provided, the better understanding the student has for a given class. Hence when presented with an unknown object that belongs to a class that had been previously learned, one expects that the greater the number of training examples that had been used in the learning process, the more likely the student will be able to accurately classify the unknown object. The reason for this is because classification is greatly aided by familiarity, which increases ones ability to identify similarity.
People utilize their natural and artificial sensors and tools during the classification process. Given an unknown object, the information output from the sensing and measuring sources is processed and a classification is made. This complex process from raw data to classification after which some action may be based can generally be understood to be pattern recognition. Human beings do this all the time; depending on the unknown to be classified, some are better at it than others.
Since machines do not tire, can reliably provide the same output for the same given set of inputs and can readily be reproduced, developing one that could learn how to recognize patterns would be extremely useful. As mentioned, there are several examples within the open literature where machines receive data and attempt to classify it in some way. Typically, this data can be represented in the form of a multidimensional vector defined within some hyperspace (Each dimension of the vector can be viewed as a feature of the data.) Therefore the pattern recognition problem can be viewed as processing this data vector in some way that produces an output, which places it into some class. In general, the approach taken for the design of the classification processor depends on the data one has available. Several approaches are usually attempted with the available data and the one that produces the best results is typically accepted.
Exemplar based machine learning techniques tackle these pattern recognition problems by learning from representative training data. These techniques can be supervised or unsupervised, classes can be generalized or specific instances can be retained for comparison purposes, and they can be trained incrementally or in a batch process. Several popular algorithms employing these techniques in various ways have been developed and published in the literature.
In supervised learning each example in the training set is associated with a known class. In unsupervised learning the training examples are not divided into classes and one attempts to form clusters or find "natural groupings" among them. The Hierarchical Clustering and Self Organizing Map algorithms have been developed in an attempt to find natural groupings among the totality of training examples and ascertain classes based on those natural groupings. It should be noted that clustering the data into natural groupings provides an opportunity for extracting useful information regarding the structure of a given class within its feature hyperspace.
Specific instance algorithms would utilize training examples without any generalization; these types of algorithms are also referred to as lazy learners. The k-Nearest Neighbor would be considered specific instance because unknown data is compared directly with individual training examples. The classes of the k "most similar" training examples to the unknown data are tallied and the classification that represents the majority of those examples selected is assigned to the unknown data. Instance Based Learning also compares unknown data to individual training examples. They function similarly to the nearest neighbor algorithm, however the training examples retained for comparison purposes vary with the instance based algorithm that is chosen. Specific instance type algorithms can become computationally expensive if one needs to compare unknown data with every training example saved. These algorithms may also have very large storage requirements as well.
Generalization algorithms combine training examples and typically compare unknown data to generalized representations of the training data; these types of algorithms are also referred to as eager learners. Hyperrectangle algorithms group training examples as rectangular shapes within the feature hyperspace with sides that are parallel to the features of the data. Unknown data classifications are made based on their proximity to these hyperrectangles. Feature partitioning algorithms attempt to partition each feature range as a series of line segments that are identified with classes based on the training examples. Preliminary classifications are made based on each of the unknown's features proximity to these line segments. As a result, for a given unknown each of its features is independently used to associate the unknown with a class. Each of these independent class associations is assigned a weight. The unknown data is then declared as the class that received the most weight. The neural network algorithms reviewed generally form hyper planes or more complex decision surfaces within the feature space, or as can be the case with support vector machines within some transformed version of the feature space. The data is generalized because whether or not an unknown vector is considered to belong to a particular class depends on which side of the decision surface it lays. The binary decision tree algorithms generalize unknown data as belonging to one branch of classes or another and work their way along various branches until they progress toward an ultimate class leaf. The hierarchical clustering and self-organizing maps formed "natural clusters" from training examples. As the natural clusters were being formed they were compared to the known classes of the training examples.
Incremental vs. Batch Learning
Incremental learning algorithms continually allow the class decision space to be modified every time a new training sample is presented. These recursive techniques are typically sensitive to the order in which the training examples are presented.
Batch learning algorithms utilize all of the training examples in their totality. These algorithms may attempt to utilize every training example as a specific instance, such as in the case of k-Nearest Neighbor. They can also generalize their training examples and solve for their parameters either iteratively or all at once. By utilizing all of the training data at once, batch learning is more likely to find optimal parameters for a given algorithm based on the training data available than incremental learning algorithms. Since batch learning algorithms utilize all of the training data at once they can be more computationally intensive than incremental learning algorithms. Whenever new training data is available, batch learning algorithms often need to reprocess the entire training set in order to obtain their parameters. Incremental learning algorithms simply update their parameters based on the new training data available. The exemplar-based machine learning method developed in this manuscript utilized batch learning to obtain the algorithm parameters.
Principal component analysis (PCA) has often been used successfully in many, many applications as a classification preprocessing feature reduction technique. This has been done on a wide range of data sets from hyperspectral images, to vegetable oil data. A nonlinear kernel based technique, KPCA, has also been developed to further utilize the feature reduction capabilities of PCA. These kernel based techniques have been used successfully for feature reduction of gene expression data. This nonlinear kernel approach is sometimes called "kernel trick" in the literature. These typical applications of PCA utilize all of the training instances as one giant cluster. Researchers have also applied PCA after breaking the training data into a series of clusters. However, the incomplete information that could be extracted when the cluster's covariance matrix is singular is typically not utilized.
The University of California at Irvine data repository was specifically established so that researchers could compare their machine learning techniques with those of other methods on common data sets. The methodology developed in this study was performed on twenty one of those data sets. However, none of the highest performing classification approaches uncovered from other researchers for the data sets assessed utilized any form of PCA to develop their technique. The reason for this may be that common applications of PCA oversimplify the class generalizations for these more complex data sets. Typically data within a given class is the result of a complicated interaction of its features therefore its mean vector and covariance matrix can be poor representations of the entire class. However, if one applies clustering and exclusion techniques within a given class, this work will show that natural groupings can be identified and adequately generalized using principal components even when a cluster's covariance matrix is singular. Therefore, instead of using the typical implementations of PCA as a feature reduction technique, which often requires a nonsingular covariance matrix, the novelty of the technique developed in this manuscript can be viewed as combining clustering, a logical exclusion process and PCA capable of handling singular covariance matrices as a subclass local feature reduction technique.
The ability to classify unknown data after learning from a training set can be extremely useful for a wide range of disciplines. The purpose of this study is to explore and develop a classification technique that is capable of segmenting arbitrary complex multidimensional classes in a way that reveals a final set of clusters which can be adequately generalized with their mean vector, relevant subspace and null space so that the tools of PCA can be harnessed (when the covariance matrix is singular) and an exemplar based machine learning algorithm can be developed. The rationale for this approach lies in the understanding that one can adequately represent a hyper ellipsoidal shaped cloud with its mean vector and covariance matrix. Given enough hyper ellipsoidal shaped clouds of various sizes and orientations one can generalize virtually any arbitrary complex shape within a multidimensional space. Therefore, the more accurately an arbitrary complex class shape can be represented, the better result one anticipates from a similarity assessment with that shape and the more accurately one expects to be able to predict the class of unknown data.
Exemplar based learning methods implicitly assume that data belonging to the same class can potentially be clustered together in some complex arbitrary shape or shapes within the hyperspace of the data features. Therefore, it is based on this reasoning that attempts are made to identify the similarity between unknown data and the specific instance or generalized concepts learned from the training examples. Therefore, if one can adequately approximate how the multidimensional data is clustered and distributed within its feature hyperspace, it seems reasonable to expect that this knowledge could then be applied to develop improved generalized concepts for estimating classes.
Instinctively one expects each class's arbitrary complex multidimensional shape to be revealed through the distribution of an appropriate set of training instances within the pattern recognition problem's hyperspace. This work generalizes this complex shape by breaking each class down into clusters that are easy to describe mathematically. Each cluster is described by its first and second order statistics. A mental image would be that each cluster is generalized as a mean point surrounded by a hyper ellipsoidal shape cloud of size and orientation representative of the training instances from which it is composed. Unknown data vectors are compared to these clusters by calculating normalized Euclidean distances to them. The smaller the Euclidean distance, the greater the association made with the cluster. The class of the cluster with the greatest association becomes the estimated classification for the unknown. This approach has obtained very positive results when tested on two-dimensional synthetically generated data and real data taken from the University of California at Irvine data repository.

The United States of America as represented by the Secretary of the Navy


An air purification planter is disclosed which comprises a receptacle; an aeration assembly; a pot-growing plant; and, a potting media. The receptacle is of the type utilized commercially. A portion of said aeration assembly is sized and proportioned to fit within said receptacle. In the preferred embodiment, a commercial receptacle is perforated near the bottom of said receptacle in order to permit communication of said aeration assembly from the interior to the exterior of said receptacle. The aeration assembly includes an electric fan which connects to the exterior end. The fan draws air through the potting media, by the root system, and through the aeration assembly, and recirculates the cleansed air.. An alternative embodiment of the air purification planter utilizes a totem concept, and, comprises an aeration assembly; and a trellis-growing plant. In the alternate embodiment, the potting media is combined with activated charcoal to be wrapped about said aerating section.

1. Field of the Invention
This invention relates to a device for purifying air; and more particularly to a planter with an aeration system embedded in or near the root system of a plant for funneling air from a room and through an activated carbon mixture in the vicinity of the roots and re-circulated back into the room.
2. Description of the Prior Art
In recent years, there have been a number of green plant systems developed for circulating and purifying air.
Some of those systems have included utilization of activated carbon and/or some method/apparatus for forcing air through the system such as with fans. However, in those cases, the design has necessitated greater structure with limited integration or flexibility with current greenhouse plant planters.
The aforementioned devices have received limited acceptance thus far due in part to the fact that consumers have been required to purchase both a planter and said various apparatuses which has required much greater space and cost than standard planters.
In addition, it has been seen that plants grown in standard planters and then subjected to a different environment as created by the air purification systems do poorly unless they can adjust. Those plants that cannot adjust either die or do not flourish and hence the air purification systems do not perform as desired.
Accordingly, in order to overcome the above set forth problem of space and flexibility, there is a need for a simplified device which is structured to be utilized in conjunction with standard planters as found commonly with commercial plant growers; requires no second pot apparatus; reduces the incidence of plant shock; and, has greater acceptance with growers.


Embodiments of the invention relate to a variable-width command/address bus (CA bus). In one embodiment, a memory controller includes first logic to determine whether a memory device is in a first mode or a second mode. The memory controller includes second logic to transmit a command to the memory device with a command/address bus having a first width over a first number of clock edges when the memory device is in the first mode, and with the command/address bus having a second width over a second number of clock edges when the memory device is in the second mode.

A variety of integrated circuit packaging techniques exist which have different benefits for different applications. For example, a ball grid array (BGA) package is one type of packaging for integrated circuits. In a BGA package, a surface of the package provides pins to interconnect with other circuits (e.g., via a grid of solder balls). The BGA package is not mounted on top of other packages, and generally sits on a circuit board (e.g., a motherboard). Another example of packaging for integrated circuits is a package on package (PoP) configuration. In PoP configurations, two or more packages are positioned on top of one another. PoP configurations can be useful for compact computing applications (e.g., smartphones, tablets, netbooks, cameras, and other compact electronic devices) due to the ability to vertically stack integrated circuit packages, and achieve a high density of integrated circuits. PoP configurations can use solder balls like BGA packages, but due to the stacked nature, PoP configurations generally have pins on the periphery of the package instead of spread over an entire surface of the package, and therefore have less area for pins. Other packaging types also exist which allow for varying numbers of pins and circuit density.
Memory devices can be packaged via different methods, but packaging configurations for a given memory device are limited by, for example, the number of available pins. A given memory device generally requires a particular number of pins for uses such as the command/address bus, the data bus, and/or other pins such as control pins. For example, if a given memory device requires a certain number of pins, and a PoP configuration will make available fewer pins than necessary for that memory device, then a PoP configuration may not be used for that memory device. Therefore, with current technology, a given memory device may have limited packaging options, and therefore be used in limited computing applications.
Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein.


A method, and resultant structure, is described for fabricating a DRAM trench capacitor with a single pillar recessed below the level of the top surface of the silicon substrate in which it is formed. First and second insulating layers are formed over the silicon substrate, and patterned to form an opening to the silicon substrate. A portion of the silicon substrate is removed in the region defined by the opening, whereby a first trench is formed. Sidewall spacers are formed along the sides of the first trench from a third insulating layer. A first pillar is formed after depositing a first conductive layer between the sidewall spacers and over the trench and removing the first conductive layer except within the first trench. The sidewall spacers are removed. A portion of the silicon substrate in the first trench is removed that is not vertically masked by the pillar, and simultaneously a portion top of the pillar is removed, whereby a second trench and second pillar are formed at a greater depth in the silicon substrate. The remainder of the second insulating layer is also removed. A capacitor dielectric is formed in the second trench over the second pillar. A second conducting layer is formed over the dielectric layer and removed in the region outside of the trench to form the top capacitor electrode.

(1) Field of the Invention
This invention relates to a method of making and the resultant structure for a capacitor for use with a DRAM (Dynamic Random Access Memory) device, and more particularly to a method for producing a DRAM trench capacitor with a recessed pillar.
(2) Description of the Related Art
A typical DRAM cell consists of a single transistor and a storage capacitor. Digital information is stored in the capacitor and accessed through the transistor, by way of addressing the desired memory cell, which is connected with other such cells through an array of bit lines and word lines. In order to construct high density DRAMs in a reasonably sized chip area, both the transistor and capacitor elements must occupy a minimum of lateral space in each memory cell. As DRAMs are scaled down in dimensions, there is a continuous challenge to maintain a sufficiently high stored charge per capacitor unit area. Efforts to increase capacitance without increasing the planar area of the capacitor have been concentrated on building three dimensional capacitor structures, which increase the capacitor surface area. Thus cell structures have to change from the conventional planar-type capacitors to either trench capacitors or stack capacitors, in particular at densities above 4 Mbit.
When the stacked capacitor approach is used to fabricate 16 Mbit DRAMs and beyond, very complicated stacked structures are needed, such as fin structures, crown structures, and so forth. These typically are difficult to manufacture, and make it more difficult to form subsequent layers due to topological problems.
The trench capacitor is typically built in an opening in the substrate and thus does not effect the topology. When fabricating trench capacitors for DRAMs with densities of 16 Mbit and beyond, however, the trench needs to be very deep. There are technology and even theoretical physical limitations to processing the deep trenches that would be needed. Prior art single trenches must be 10 to 15 micrometers deep with a diameter of 0.5 micrometers. A further problem with deep trenches is that the wafer may become mechanically unstable with so many deep trenches, for in a 64 Mbit memory, for example, 64 million trenches (at one capacitor per cell) are needed.
Workers in the art are aware of these problems, and have attempted to resolve them. For example, in U.S. Pat. No. 5,204,280 (Dhong et al) a method is shown for forming multiple recessed pillars in a shallow trench in a silicon substrate. Hemispherical grain polysilicon is used as an etch mask to form the pillars. In U.S. Pat. No. 5,256,588, Witek et al describe the formation of a pillar in a trench capacitor over which the DRAM transistor is subsequently formed.

Method for fabricating a DRAM trench capacitor with recessed pillar

Industrial Technology Research Institute


A motor driving system includes a power supply unit, a voltage-stabilizing unit, a signal-generating unit, a comparing unit, and a control unit. The power supply unit provides an input supply voltage to each other unit in the system. The voltage-stabilizing unit includes a voltage-stabilizing element and produces a constant voltage. The signal-generating unit generates an input signal, which varies with high and low levels of the input supply voltage. The comparing unit compares the constant voltage with the input signal to generate a comparison signal. The control unit controls a motor's rotating speed according to the comparison signal generated by the comparing unit. When the input supply voltage is low, a lowest rotating speed is set for the control unit to control the rotating of the motor.

According to the characteristics of driving elements of the currently available fan motors, when an input supply voltage thereof is high, the fan is driven to rotate at full speed to increase a cooling efficiency thereof, and when the input supply voltage thereof is low, the fan is driven to rotate at a lowest possible speed. That is, the fan speed is adjusted according to a linear change in the high and low level of the input supply voltage. In this manner, the lowest rotating speed of the fan at the low input supply voltage is a fixed value that could not be varied. Therefore, the fan has limited applications and could not always meet consumers' needs.
It is therefore tried by the inventor to develop an improved motor driving system to eliminate drawbacks existed in the conventional fan motors.


A liquid crystal display device includes (a) a first substrate including a first area in which an incident light is reflected and a second area through which a light passes, and further including a pixel electrode covering the first and second areas therewith, (b) a second substrate including at least an opposing electrode, (c) a liquid crystal layer sandwiched between the first and second substrates and including liquid crystal molecules each having a major axis aligned perpendicularly to the first and second substrates when no electric field is applied thereto, and (d) a first alignment-controller for controlling alignment of the liquid crystal molecules, the first alignment-controller being arranged at a boundary of the first and second areas or in the vicinity of the boundary.

1. Field of the Invention
The invention relates to a liquid crystal display device, and more particularly to a half-transmission type liquid crystal display device having functions of a light-transmission type liquid crystal display device and a light-reflection type liquid crystal display device.
2. Description of the Related Art
A liquid crystal display device is generally comprised of two substrates and liquid crystal sandwiched between the two substrates, in which an intensity of electric field to be applied to the liquid crystal is controlled to thereby control a degree at which backlight passes through the liquid crystal.
A vertical-alignment type liquid crystal display device can completely shut out a light when no electric field is applied thereto. Namely, since a luminance in off-condition in a normally black mode is quite low, a vertical-alignment type liquid crystal display device can present a high contrast ratio in comparison with a conventional twisted nematic type liquid crystal display device.
In general, backlight consumes 50% or more among power consumed in a liquid crystal display device. Hence, a portable communication device is often designed to include a light-reflection type liquid crystal display device which includes a light-reflector in place of a backlight source for displaying images only by incident lights.
However, a light-reflection type liquid crystal display device is accompanied with a problem that displayed images cannot be seen when it is dark around the device.
As a solution to the problem, there has been suggested a half-transmission type liquid crystal display device including a light-reflection area and a light-transmission area, as a liquid crystal display device having advantages of both of a light-reflection type liquid crystal display device and a light-transmission type liquid crystal display device. For instance, Japanese Patent No. 2955277 has suggested such a half-transmission type liquid crystal display device.
FIG. 1 is a cross-sectional view of a first example of a conventional half-transmission type liquid crystal display device.
A half-transmission type liquid crystal display device 100 illustrated in FIG. 1 is comprised of a first substrate 101, a second substrate 102, and a liquid crystal layer 103 sandwiched between the first and second substrates 101 and 102.
The second substrate 102 is comprised of a second electrically insulating transparent substrate 104, an opposing electrode 105 composed of ITO (indium tin oxide) formed on the second transparent substrate 104 in facing relation to the liquid crystal layer 103, an alignment film 106 formed on the opposing electrode 105, an optical compensator 107 formed on the second transparent substrate 104 in opposite side with respect to the liquid crystal layer 103, and a polarizer 108 formed on the optic compensator 107.
The half-transmission type liquid crystal display device 100 is designed to have a first area 120 in which a light is reflected and a second area 121 through which a light passes. A structure of the first substrate 101 in the first area 120 is different from a structure of the first substrate 101 in the second area 121.
In the first area 120, the first substrate 101 is comprised of a first electrically insulating transparent substrate 109, a passivation film 110 formed on the first transparent film 109 in facing relation to the liquid crystal layer 103, a pixel electrode 111 composed of ITO and formed on the passivation film 110, a dielectric layer 112 formed on the pixel electrode 111 and having a wavy surface, a pixel electrode 113 covering the dielectric layer 112 therewith in wavy configuration and composed of aluminum, an alignment film 114 covering the pixel electrode 113 therewith, an optical compensator 115 formed on the first transparent substrate 109 in opposite side with respect to the liquid crystal layer 103, and a polarizer 116 formed on the optic compensator 115.
In the second area 121, the first substrate 101 is comprised of a first electrically insulating transparent substrate 109, a passivation film 110 formed on the first transparent film 109 in facing relation to the liquid crystal layer 103, a pixel electrode 111 composed of ITO and formed on the passivation film 110, an alignment film 114 formed on the pixel electrode 111, an optical compensator 115 formed on the first transparent substrate 109 in opposite side with respect to the liquid crystal layer 103, and a polarizer 116 formed on the optic compensator 115.
In the half-transmission type liquid crystal display device 100, liquid crystal molecules constituting the liquid crystal layer 103 are aligned so that major axes of them are perpendicular to the first and second substrates 101 and 102 when no electric field is applied to the liquid crystal display device 100. The liquid crystal molecules have negative dielectric anisotropy.
FIG. 2 is a cross-sectional view of a second example of a conventional half-transmission type liquid crystal display device.
A half-transmission type liquid crystal display device 150 illustrated in FIG. 2 is different from the half-transmission type liquid crystal display device 100 illustrated in FIG. 1 in a structure of the first substrate 101 in the first area 120.
That is, in the half-transmission type liquid crystal display device 150, the pixel electrode 113 composed of aluminum is covered with the pixel electrode 111 composed of ITO, and the alignment film 114 is formed on the pixel electrode 111. Except this difference, the half transmission type liquid crystal display device 150 is identical in structure to the half-transmission type liquid crystal display device 100.
The half-transmission type liquid crystal display device 100 illustrated in FIG. 1 displays images as follows.
In the first area 120, an external light enters the half-transmission type liquid crystal display device 100, and is reflected at the pixel electrode 113 acting as a reflector. Then, the reflected light passes through the liquid crystal layer 103 and the second substrate 102, and reaches a viewer.
In the second area 121, a backlight emitted from a backlight source (not illustrated) arranged below the first transparent substrate 109 passes through the first substrate 101, the liquid crystal layer 103 and the second substrate 102, and reaches a viewer.
As mentioned above, whereas an incident light reciprocates the liquid crystal layer 103 in the first area 120, an incident light passes through the liquid crystal layer 103 only in one-way in the second area 121, resulting in an optical path difference in the liquid crystal layer 103. In order to avoid such an optical path difference, a cell gap Dr of liquid crystal in the first area 120 is designed to be about half of a cell gap Df of liquid crystal in the second area 121, thereby optimizing an intensity of an output light caused by a difference in retardation between the first and second areas 120 and 121.
For instance, the cell gaps Dr and Df are designed equal to 2 μm and 4 μm, respectively.
The half-transmission type liquid crystal display device 150 illustrated in FIG. 2 displays images in the same way as the half-transmission type liquid crystal display device 100.
In order to make use of advantages provided by the above-mentioned half-transmission type liquid crystal display device and vertical-alignment type liquid crystal display device, Japanese Patent Application Publications Nos. 2000-29010 and 2000-35570 suggest a liquid crystal display device having function of both of half-transmission type and vertical-alignment type liquid crystal display devices.
A half transmission type liquid crystal display device having the first and second areas unavoidably has the cell gaps Dr and Df different from each other, in order to avoid the above-mentioned optical path difference in the liquid crystal layer 103.
However, the cell gaps Dr and Df different from each other cause a problem that liquid crystal molecules are inclined in non-uniform directions at a boundary between the first and second areas and in the vicinity of the boundary when electric field is applied to the liquid crystal layer, resulting in deterioration in visibility and reduction in a response speed.
Japanese Patent No. 2565639, based on U.S. patent application Ser. No. 879,256 filed on Apr. 30, 1992, has suggested a liquid crystal display device including a common electrode formed on a substrate. The common electrode is formed in alignment with a display area with a patterned opening for dividing the display area into a plurality of liquid crystal domains, and covers the substrate therewith in an area other than the opening.
Japanese Patent Application Publication No. 2000-250056 has suggested a liquid crystal display device including a pixel electrode formed with an opening in the form of a slit and in parallel with an orientation of alignment of liquid crystal molecules.
Japanese Patent Application Publication No. 2002-107724 has suggested a liquid crystal display device including a λ/4 double-refraction layer arranged between a light-reflection layer and a liquid crystal layer to thereby equalize a thickness of the liquid crystal layer in a light-reflection area to a thickness of the liquid crystal layer in a light-transmission area.
Japanese Patent Application Publication No. 2002-98951 has suggested a half-transmission type liquid crystal display device including a reflection electrode having a patterned opening having a side which is not in parallel with any sides of an effective frame of a liquid crystal display panel and any sides of a pixel pattern.


Compounds, compositions and methods for altering insulin secretion, particularly in the context of treatment of subjects having, or suspected of being at risk for having, diabetes mellitus. The compounds have the following structure (I): including stereoisomers, prodrugs and pharmaceutically acceptable salts thereof, wherein W1, W2, X, R1, R2, R3, R4, m and n are defined herein.

Type 2 diabetes mellitus, or "late onset" diabetes, is a common, degenerative disease affecting 5 to 10 percent of the population in developed countries. The propensity for developing type 2 diabetes mellitus ("type 2 DM") is reportedly maternally inherited, suggesting a mitochondrial genetic involvement. (Alcolado, J. C. and Alcolado, R., Br. Med. J. 302:1178-1180 (1991); Reny, S. L., International J. Epidem. 23:886-890 (1994)). Diabetes is a heterogeneous disorder with a strong genetic component; monozygotic twins are highly concordant and there is a high incidence of the disease among first degree relatives of affected individuals.
At the cellular level, the pathologic phenotype that may be characteristic of the presence of, or risk for predisposition to, late onset diabetes mellitus includes the presence of one or more indicators of altered mitochondrial respiratory function, for example impaired insulin secretion, decreased ATP synthesis and increased levels of reactive oxygen species. Studies have shown that type 2 DM may be preceded by or associated with certain related disorders. For example, it is estimated that forty million individuals in the U.S. suffer from impaired glucose tolerance (IGT). Following a glucose load, circulating glucose concentrations in IGT patients rise to higher levels, and return to baseline levels more slowly, than in unaffected individuals. A small percentage of IGT individuals (5-10%) progress to non-insulin dependent diabetes (NIDDM) each year. This form of diabetes mellitus, type 2 DM, is associated with decreased release of insulin by pancreatic beta cells and a decreased end-organ response to insulin. Other symptoms of diabetes mellitus and conditions that precede or are associated with diabetes mellitus include obesity, vascular pathologies, peripheral and sensory neuropathies and blindness.
Glucose-mediated insulin secretion from the pancreatic beta cell is triggered by a complex sequence of intracellular events. Glucose is taken up by the beta cell via GLUT-2 glucose transporters; it is subsequently phosphorylated by glucokinase to glucose-6-phosphate, which enters the glycolytic pathway. The reducing equivalents (NADH) and substrate (pyruvate) produced through glycolysis enter the mitochondria and fuel increased respiration and oxidative phosphorylation. The consequent rise in cellular ATP levels triggers closure of the K+-ATP channels at the plasma membrane, depolarizing the membrane and permitting influx of calcium. Calcium appears to have two main roles: stimulating release of insulin from the cells (e.g., Kennedy et al., 1996 J. Clin. Invest. 98:2524; Maechler et al., 1997 EMBO J. 16:3833), and acting as a "feed-forward" regulator of mitochondrial ATP production (e.g., Cox and Matlib, 1993 Trends Pharmacol. Sci. 14:408). The latter is accomplished by mitochondrial uptake of calcium through the mitochondrial calcium uniporter (e.g., Newgard et al., 1995 Ann. Rev. Biochem. 64:689; Magnus et al., 1998 Am. J. Physiol. 274:C1174-C1184). The rise in mitochondrial calcium stimulates respiration and oxidative phosphorylation through stimulation of calcium-sensitive dehydrogenase (Rutter et al., 1988 Biochem. J. 252:181; Rutter et al., 1993 J. Biol. Chem. 268:22385). However, the rise in mitochondrial calcium is transient, since calcium returns to the cytoplasm through regulated calcium efflux channels, for instance a mitochondrial calcium antiporter such as the mitochondrial calcium/sodium antiporter (MCA) also known as the mitochondrial sodium/calcium exchanger (mNCE; see, e.g., Newgard 1995; Magnus 1998; for a general review of mitochondrial membrane transporters, see, e.g., Zonatti et al., 1994 J. Bioenergetics Biomembr. 26:543 and references cited therein). The use of MCA inhibitors has been contemplated for their potential effects on cardiac function (e.g., Cox and Matlib, 1993 Trends Pharmacol. Sci. 14:408-413), but such use has not been suggested for certain other indications such as diabetes. Thus, for example, while elevated intramitochondrial calcium concentration has been correlated with insulin secretion and oxidative ATP synthesis, as noted above (e.g., Kennedy et al., 1996 J. Clin. Invest. 98:2524; Maechler et al., 1997 EMBO J. 16:3833; Cox and Matlib, 1993 Trends Pharmacol. Sci. 14:408), no inducer-effector relationship between oxidative ATP synthesis and insulin secretion has been universally accepted (see, e.g., Newgard, 1995 Ann. Rev. Biochem. 64:689). Moreover, currently available inhibitors of the MCA are regarded as either not specific for the MCA, or useful only at extremely high concentrations, precluding their apparent suitability for pharmaceutical compositions (Cox and Matlib, 1993 Trends Pharmacol. Sci. 14:408-413).
Current pharmacological therapies for type 2 DM include injected insulin, and oral agents that are designed to lower blood glucose levels. Currently available oral agents include: (i) the sulfonylureas, which act by enhancing the sensitivity of the pancreatic beta cell to glucose, thereby increasing insulin secretion in response to a given glucose load; (ii) the biguamides, which improve glucose disposal rates and inhibit hepatic glucose output; (iii) the thiazolidinediones, which improve peripheral insulin sensitivity through interaction with nuclear peroxisome proliferator-activated receptors (PPAR, see, e.g., Spiegelman, 1998 Diabetes 47:507-514; Schoonjans et al., 1997 Curr Opin. Lipidol. 8:159-166; Staels et al., 1997 Biochimie 79:95-99); (iv) repaglinide, which enhances insulin secretion through interaction with ATP-dependent potassium channels; and (v) acarbose, which decreases intestinal absorption of carbohydrates. Although currently available drugs for treating type 2 diabetes, such as the sulfonylureas, improve insulin secretion, both basal and insulin stimulated insulin secretion are enhanced by such compounds. Consequently, undesirable chronic hyperinsulinemia, hypoglycemia and/or excessive weight gain may result following treatment with such drugs (Cobb et al., 1998 Ann. Rep. Med. Chem. 33:213-222; Krentz et al., 1994 Drug Safety 11:223-241).
None of the current pharmacological therapies corrects the underlying biochemical defect in type 2 DM. Neither do any of these currently available treatments improve all of the physiological abnormalities in type 2 DM such as impaired insulin secretion, insulin resistance and/or excessive hepatic glucose output. In addition, treatment failures are common with these agents, such that multi-drug therapy is frequently necessary.
Mitochondria are organelles that are the main energy source in cells of higher organisms. These organelles provide direct and indirect biochemical regulation of a wide array of cellular respiratory, oxidative and metabolic processes, including metabolic energy production, aerobic respiration and intracellular calcium regulation. For example, mitochondria are the site of electron transport chain (ETC) activity, which drives oxidative phosphorylation to produce metabolic energy in the form of adenosine triphosphate (ATP), and which also underlies a central mitochondrial role in intracellular calcium homeostasis. These processes require the maintenance of a mitochondrial membrane electrochemical potential, and defects in such membrane potential can result in a variety of disorders.
Mitochondria contain an outer mitochondrial membrane that serves as an interface between the organelle and the cytosol, a highly folded inner mitochondrial membrane that appears to form attachments to the outer membrane at multiple sites, and an intermembrane space between the two mitochondrial membranes. The subcompartment within the inner mitochondrial membrane is commonly referred to as the mitochondrial matrix (for review, see, e.g., Ermster et al., J. Cell Biol. 91:227s, 1981). While the outer membrane is freely permeable to ionic and non-ionic solutes having molecular weights less than about ten kilodaltons, the inner mitochondrial membrane exhibits selective and regulated permeability for many small molecules, including certain cations, and is impermeable to large (greater than about 10 kD) molecules.
Four of the five multisubunit protein complexes (Complexes I, III, IV and V) that mediate ETC activity are localized to the inner mitochondrial membrane. The remaining ETC complex (Complex II) is situated in the matrix. In at least three distinct chemical reactions known to take place within the ETC, protons are moved from the mitochondrial matrix, across the inner membrane, to the intermembrane space. This disequilibrium of charged species creates an electrochemical membrane potential of approximately 220 mV referred to as the "proton motive force" (PMF). The PMF, which is often represented by the notation Δp, corresponds to the sum of the electric potential (ΔΨm) and the pH differential (ΔpH) across the inner membrane according to the equationΔp=ΔΨm−ZΔpHwherein Z stands for −2.303 RT/F. The value of Z is −59 at 25° C. when Δp and ΔΨm are expressed in mV and ΔpH is expressed in pH units (see, e.g., Emster et al., J. Cell Biol. 91:227s, 1981, and references cited therein).
ΔΨm provides the energy for phosphorylation of adenosine diphosphate (ADP) to yield ATP by ETC Complex V, a process that is coupled stoichiometrically with transport of a proton into the matrix. ΔΨm is also the driving force for the influx of cytosolic Ca2+ into the mitochondrion. Normal alterations of intramitochondrial Ca2+ are associated with normal metabolic regulation (Dykens, 1998 in Mitochondria & Free Radicals in Neurodegenerative Diseases, Beal, Howell and Bodis-Wollner, Eds., Wiley-Liss, New York, pp. 29-55; Radi et al., 1998 in Mitochondria & Free Radicals in Neurodegenerative Diseases, Beal, Howell and Bodis-Wollner, Eds., Wiley-Liss, New York, pp. 57-89; Gunter and Pfeiffer, 1991, Am. J. Physiol. 27: C755; Gunter et al., Am. J. Physiol. 267:313, 1994). For example, fluctuating levels of mitochondrial free Ca2+ may be responsible for regulating oxidative metabolism in response to increased ATP utilization, via allosteric regulation of enzymes (reviewed by Crompton and Andreeva, Basic Res. Cardiol. 88:513-523, 1993), and the glycerophosphate shuttle (Gunter and Gunter, J. Bioenerg. Biomembr. 26:471, 1994).
Normal mitochondrial function includes regulation of cytosolic free calcium levels by sequestration of excess Ca2+ within the mitochondrial matrix, including transiently elevated cytosolic free calcium that results from physiologic biological signal transduction. Depending on cell type, cytosolic Ca2+ concentration is typically 50-100 nM. In normally functioning cells, when Ca2+ levels reach 200-300 nM, mitochondria begin to accumulate Ca2+ as a function of the equilibrium between influx via a Ca2+ uniporter in the inner mitochondrial membrane and Ca2+ efflux via both Na+ dependent and Na+ independent calcium carriers, including notably the MCA. The low affinity of this rapid uniporter mechanism suggests that the primary uniporter function may be to lower cytosolic Ca2+ in response to elevation of cytosolic free calcium levels, which may result from calcium influx across the plasma membrane that occurs as part of a biological signal transduction mechanism (Gunter and Gunter, J. Bioenerg. Biomembr. 26:471, 1994; Gunter et al., Am. J. Physiol. 267:313, 1994). In certain instances, for example in pancreatic beta cells, physiologic rises in cytoplasmic calcium occur in response to glucose (or other secretagogues) and lead to calcium uptake by mitochondria, stimulating increased ATP synthesis. Similarly, the primary calcium antiporter (e.g., MCA) function may be to lower mitochondrial Ca2+ concentrations in response to mitochondrial Ca2+ influxes, such as may result from glucose stimulation of a glucose-sensitive cell, and which produce transient increases in oxidative ATP synthesis. Thus, mitochdndrially regulated calcium cycling between, inter alia, cytosolic and mitochondrial compartments may provide an opportunity for manipulation of intracellular ATP levels (e.g., Cox and Matlib, 1993 Trends Pharmacol. Sci. 14:408-413; Matlib et al., 1983 Eur. J. Pharmacol. 89:327; Matlib 1985 J. Pharmacol. Exp. Therap. 233:376; Matlib et al. 1983 Life Sci. 32:2837).
In view of the significance of mitochondrial regulation of intracellular calcium and the relationship of this mitochondrial activity to diabetes, which includes any of a wide range of disease states characterized by inappropriate and sustained hyperglycemia, there is clearly a need for agents to control mitochondrial calcium homeostasis. To provide improved therapies for diabetes, agents that alter mitochondrial calcium cycling between intramitochondrial and extramitochondrial subcellular compartments would be beneficial. Further, there is a need for improved therapeutics that are targeted to correct biochemical and/or metabolic defects responsible for, or associated with, type 2 DM, regardless of whether such a defect underlying altered mitochondrial function may have mitochondrial or extramitochondrial origins.
Accordingly, there is a need in the art agents that modulate mitochondrial calcium/sodium antiporter function and are thus useful for treating diabetes, type 2 DM, by enhancing insulin secretion. There is also a need for pharmaceutical compositions containing such agents, as well as for methods relating to use thereof. The present invention fulfills these needs, and provides further related advantages.

Compounds for inhibiting insulin secretion and methods related thereto


A gas bearing part is provided, having gas supply means which open out into a recessed working surface which can be placed opposite a carrier plate to permit formation of a gas bearing relative to the carrier plate.. To obtain a friction-free movement, also with application of higher gas pressures the roughness of the working surface is less than 10 ru, preferably less than 4 ru. The working surface is further essentially conically recessed, whereby the tip of the conical recess is essentially in the centre of the surface.

The invention relates to a gas bearing part provided with gas supply means which open out into a recessed working surface of said gas bearing part which can be placed opposite a carrier plate to permit formation of a gas bearing relative to the carrier plate.
Such a gas bearing part is generally known, and the above-mentioned recesses can be in many different forms.
Although this known gas bearing part permits friction-free movement between gas bearing part and carrier plate, while the flow of the gas is low, so that the gas bearing requires only a small quantity of gas for its functioning, it has been found that the resistance of the bearing to changing loads, i.e. the pressure which the gas bearing withstands under load without coming into contact with the carrier, calls for very high gas pressures.
However, higher gas pressures soon lead to instability of the gas bearing, which is accompanied by the occurrence of vibrations.
Of course, this is not permissible where such gas bearing parts are being used for movements requiring very great precision.

Gas bearing part, and device provided with such a gas bearing part


Selenium exists in oil refinery stripped sour water as selenocyanate and can be effectively removed using an acrylic, strong base, anion exchange column or stannous chloride. The acrylic, strong base, anion exchange column can also be employed to remove arsenic, iron, and vanadium from an aqueous fluid.

This invention relates to (a) processes for removing selenocyanate, arsenic, iron, and vanadium from an aqueous fluid and, in particular, to a method for reducing the concentration of these materials in an oil refinery effluent, and (b) an apparatus for removing selenate and selenite from an aqueous fluid.
Several parts of the San Francisco Bay Estuary, including Suisun Bay, San Pablo Bay, and the Carduinez Straits, have been classified by the U.S. Environmental Protection Agency (EPA) under Section 304(1) of the Clean Water Act as impaired due to the impact of selenium on waterfowl. As a result of this classification, in 1991 the San Francisco Regional Water Quality Control Board (Board) amended the National Pollution Discharge Elimination System (NPDES) permits for the six refineries discharging into the estuary to include specific permit limits on total selenium, with a compliance deadline of Dec. 12, 1993. Each refinery was given a mass discharge limit for total selenium. This limit was based on either previous performance, or an effluent concentration of 50 parts per billion (ppb), whichever resulted in the lower limit.
Even before the establishment of the limit on total selenium by the Board, the various refineries had been working to develop control strategies, including treatment options, to meet the 50 ppb limit on total selenium. Nevertheless, despite studying over 50 treatment technology variations, no treatment option was found or developed to achieve this limit which did not have serious negative environmental consequences, such as generation of large amounts of hazardous sludge or increased levels of copper in the effluent.
Among the numerous technologies tested was an ion exchange process described in U.S. Pat. No. 4,915,928 and several acidification techniques. However, since no new control option could be developed in time to meet the December, 1993 compliance deadline for the 50 ppb limit, the refineries requested an extension of the compliance period in a proposal to the San Francisco Regional Water Quality Control Board entitled Removal of Selenium from Refinery Discharges ("Extension Proposal"). In the Extension Proposal, the ion exchange process is summarized as follows:
Chevron Ion Exchange Process
Chevron developed an ion exchange process using a Type 1 gel resin. The process concentrates selenium from dilute solutions and produces a stable selenium product. The process was tested at the pilot scale and achieved greater than 90% removal for two SSW {stripped sour water} streams, but only poor removal for two other SSW streams which contained the majority of selenium {citing Chevron. Control strategy for selenium. Mar. 31, 1989. Report submitted to Regional Water Quality Control Board ("Chevron Report")}. Even with the stream on which the ion exchange was effective, the process was vulnerable to upset conditions in the sour water strippers {citing Chevron Report}.
Furthermore, the Extension Proposal (Table 3, page 11) notes that the Chevron ion exchange technology is "not feasible despite observed effectiveness." In addition, the Chevron Report at page 21 states:
The Chevron Ion Exchange Process for removing selenium from Richmond Refinery stripped sour waters is not practicable because:
* Costs, roughly $11,000/lb removed, are orders of magnitude above what EPA reports in its cost-effectiveness guidance; PA1 * Receiving water selenium concentrations are orders of magnitude below the level the SWRCB {sic; State Regional Water Quality Control Board} recommends as below harmful effects. PA1 Acidification/Degassing PA1 Selenium is present in sour water as the selenide (Se.sup.2-) or biselenide (HSe.sup.-) anion as would be expected if selenium behaves similarly to sulfur, stripping of the sample at reduced pH should remove selenium. Exxon tested this method on samples of (unstripped) sour water and found that a significant fraction of the selenium could be removed by heating samples of sour water at low pH {citation omitted}. This is consistent with their finding that selenium is stripped along with sulfur in the sour water strippers. However, Exxon also found that a maximum of about 60% selenium removal could be achieved at a pH of 1. Such a low pH is impractical to operate at, and 60% removal from sour water would not be nearly sufficient to meet a 50 ppb limit. Acidification/degassing on sour water stripper bottoms (stripped sour water--SSW) was tested by Exxon, Shell, and Unocal {citations omitted}. Only poor removal (<30%) could be obtained when either air or nitrogen sparging at pH <2 was used. Acidification followed by aeration may also remove soluble selenium by oxidizing selenide to elemental selenium which is then allowed to precipitate. Chevron found that a maximum of 47% removal could be achieved in this manner, and the results were not very reproducible.
The Extension Proposal comments on the acidification procedures as follows:

Method for reducing the selenium concentration in an oil refinery effluent


AB-polybenzoxazole monomer, such as 3-amino-4-hydroxybenzoic acid, can be synthesized in high yields from a hydroxy-benzoic acid or related compound in a three-step process of (1) nitration, (2) hydrolysis of the ester, and (3) reduction of the nitro moiety. The monomer is conveniently recovered as a phosphate salt in high purity by precipitating and recrystallizing from a phosphoric acid solution.

The present invention relates to AB-polybenzoxazole (AB-PBO) monomers and processes for synthesizing them.
AB-polybenzoxazole monomers comprise:
(1) an aromatic group; PA0 (2) an o-amino-hydroxy moiety bonded to said aromatic group, which consists of a primary amine group bonded to said aromatic group and a hydroxy group bonded to said aromatic group in a position ortho to said primary amine group: and PA0 (3) an electron-deficient carbon group linked to said aromatic group. PA0 (1) an aromatic group: and PA0 (2) an oxazole ring fused to said aromatic group and linked at the 2-carbon to an aromatic group in an adjacent mer unit. PA0 (1) contacting a hydroxy-ester compound comprising: PA0 (2) converting the nitrated hydroxy-ester of step (1) to a water-soluble nitrated hydroxy-benzoate salt and dissolving said water-soluble salt in an aqueous solvent: and PA0 (3) contacting the water-soluble salt product of step (2) with a hydrogenating agent in the presence of a transition-metal-containing hydrogenation catalyst in an aqueous solution under conditions such that the nitrate group of said water-soluble salt is hydrogenated to form an amine group.
AB-polybenzoxazole monomers preferably conform with formula I: ##STR1## wherein Q is an electron-deficient carbon group: Ar is an aromatic group: and the amine and hydroxy groups are in ortho position with respect to each other.
The monomer is polymerized by polycondensation in a non-oxidizing solvent acid, such as methanesulfonic acid or polyphosphoric acid, at elevated temperatures, as described in Sybert et al., Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,772,678 (Sept. 20, 1988): Wolfe et al., Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,703,103 (Oct. 27, 1987): Wolfe et al., Liquid Crystalline Polymer Compositions, Process and Products, U.S Pat. No. 4,533,692 (Aug. 6, 1985): Wolfe et al., Liquid Crystalline Poly(2,6-Benzothiazole) Compositions, Process and Products, U.S. Pat. No. 4,533,724 (Aug. 6, 1985); Wolfe, Liquid Crystalline Polymer Compositions, Process and Products, U.S. Pat. No. 4,533,693 (Aug. 6, 1985): Evers, Thermoxidatively Stable Articulated p-Benzobisoxazole and p-Benzobisthiazole Polymers, U.S. Pat. No. 4,359,567 (Nov. 16, 1982); Tsai et al., Method for Making Heterocyclic Block Copolymer, U.S. Pat. No. 4,578,432 (Mar. 25, 1986) and 11 Ency. Poly. Sci. & Eng., Polybenzothiazoles and Polybenzoxazoles, 601 (J. Wiley & Sons 1988).
The resulting polymers comprise a plurality of mer units which each contain:
The polymers preferably comprise a moiety which conforms to formula II ##STR2## wherein n is a number of repeating units in excess of one.
The o-amino-hydroxy moiety of the AB-PBO monomer is extremely sensitive to air oxidation as a free base, so the monomer is ordinarily stored as an acid salt of hydrogen chloride. The release of hydrogen chloride gas during polymerization causes foaming of the polymerization mixture which can interfere with the reaction. Typically, the monomer is dehydrohalogenated at moderate temperatures and, optionally, reduced pressure, in a solution of polyphosphoric acid having low viscosity, and then phosphorus pentoxide is added to the solution before polymerizing to high molecular weight, as described in U.S. Pat. No. 4,533,693 which is previously incorporated by reference. The dehydrohalogenation step requires time and requires that equipment be made of materials which are inert with respect to hydrogen halide gases. What is needed is a monomer which does not require a dehydrohalogenation step.
The condensation of AB-PBO is a polycondensation reaction. In such a reaction, the purity of the resulting monomer is critical, because impurities containing only one reactive group act as chain-terminating agents which hold down the molecular weight of the resulting polymer. What is needed is a high yield process to synthesize AB-PBO monomer having a high purity.

Process to synthesize AB-PBO monomer and phosphate salts thereof


A traffic cone rack adapted to be mounted on a bumper, a floor or side panel of a vehicle. The device includes an elongated body portion adapted for securing to a portion of a vehicle. A cone support bail projects outward from the body for receiving traffic cones. A cone locking bail is tiltably secured to the body and moves over a fulcrum point for locking the traffic cones on the bail in a carrying position. An adjunct to the device is a warning buzzer which sounds when the locking bail is in the open position and the ignition switch of the vehicle is on.

1. Field of the Invention
This invention pertains to a carrying rack for mounting on a vehicle to which is removably secured traffic cones for transporting from location to location. This invention generally comprises a traffic cone rack which may be secured to the bumper, floor or body panel of the vehicle for convenience in receiving and retaining rubber or plastic traffic cones.
2. Prior Art
Traffic cones are usually transported in a nesting position stacked and loaded into the cargo space of a vehicle or nestled in boxes or loading compartments. An improvement over the prior art accomplished by the device of this invention is the neat and orderly configuration and appearance not cluttering the vehicle. The device possesses an additional advantage of warning the driver of the vehicle when the ignition switch is activated and the cone locking bail is not in the secured or closed position.

Traffic cone rack for mounting on a vehicle


A control device for an axial piston machine in which the rocker controlling the angular orientation of the cylinder drum is shifted by a differential-action setting piston having a pin which engages in the rocker. The opposite end of this pin bears via a pressure body on one arm of a bell crank lever which can have a curved camming surface, the pressure body including a roller and being urged by a first spring against the bell crank lever. The other arm of the bell crank lever is engaged on one side by a control piston subjected to the pump pressure while the valve member which controls the pressure to the large-diameter side of the setting piston engages the opposite side of the bell crank lever and is urged against this opposite side by a second spring.

As can be seen from the aforementioned copending applications, the literature cited below and the references in the aforementioned copending applications, it is known to provide a control device for the setting (adjustment of displacement) of an axial piston pump which includes a setting piston constituted as a differential piston. The latter has a small effective surface which can be subjected to the output pressure of the pump directly and a large-diameter effective surface which can be subjected to this pump pressure under the control of a further element such as a valve member. Between the valve member and the setting piston, there can be provided a force-transmitting system which can include a bell crank lever.
The axial piston pump or pumps with which the system of the present invention can be used can be any of those described in the aforementioned copending applications or in the literature set forth below. In such an axial piston pump, the cylinder drum usually rides along a rocker or swingable slide which can be shifted to one side or another of an angular orientation in which the plane of the surface against which the cylinder drum reacts lies perpendicular to the axis of the drive shaft.
The axially displaceable pistons of this drum can react against the surface coupled with the drive shaft so that, depending upon the side to which the drum is swung from its neutral position in which its axis of rotation coincides with the axis of the drive shaft, one or the other port will serve as the outlet port and the angle to which the drum is swung from the neutral position will determine the displacement per revolution of the pump.
With conventional control device of the aforedescribed type, which are generally designed to maintain a constant output product of the pump for a given setting thereof, i.e. a constant product of the discharge pressure and displacement volume per revolution, the fulcrum of the bell crank lever is not fixed but is determined by the position of a pressure-measuring piston.
More particularly, the bell crank lever is fulcrumed on the pressure-measuring piston and is provided with a slit in which a pin for an element connected to the setting piston is slideable (see German open application--Offenlegungsschrift--DT-OS No. 1 653 385).
This construction has been found to be particularly unreliable and weak, especially when the machine is subjected to vibration, since the control mechanism is readily degenerated. The friction forces result in erroneous corrections of the position of the setting element and the lateral forces upon the pressure-measuring piston (control piston) give rise to an excessive wear so that increased leakage and power losses result. A further disadvantage of this system is that for given controller dimensions, the hyperbolic law of force transmission between the controlled and controlling elements can only be adjusted as to one parameter so that an optimum setting of the controller is not always possible.
In addition, the aforedescribed prior-art configuration of a control device is not suitable for setting or control systems in which the setting piston must be afforded a large piston stroke. This is especially the case in pumps in which the displaceable member is a swingable slide. In this case, difficulties are encountered because a spring sufficient to accommodate the desired stroke of the setting piston must be of large volume and hence occupy considerable space. It is also expensive to provide means for avoiding the buckling of the spring.
In yet another conventional system for the control of axial piston machines (see German open application--Offenlegungsschrift--DT-OS No. 2 003 774) at least approximately parallel to the setting piston there is provided a lever such that one end of the lever is articulated with the setting piston and between the other end of the lever and the setting piston, a spring is provided under prestress. The lever presses with its lateral face against the control slide. In this embodiment as well, the articulation or fulcrum of the lever has a changeable location and there is a disadvantage in the fact that the lever shifts the setting piston which applies lateral forces upon the control slide.
In German open application--Offenlegungsschrift--DT-OS No. 2 017 656, moreover, there is described a control device for the adjustment of an axial piston pump which includes a setting body and a setting piston connected with this setting body and formed as a differential piston. It is such a system that the present invention intends to improve upon as noted below. The differential piston has a small effective surface which is subjected directly to the output pressure of the pump and a large effective surface which is pressurized with the output pressure of the pump via a control element such as a valve member. A control slide is used in this system as well and a bell crank lever is provided whose fulcrum is fixed on the housing and a force-transmitting member is connected with the setting piston and has a pressure body which lies perpendicular to the axis of the setting piston and bears against one shank or arm of the bell crank lever. In this system as well disadvantages are encountered since the provision of the control piston in the setting piston is extremely expensive and the arrangement subjects the control piston and the setting piston to lateral forces which are extremely disadvantageous.
Still another arrangement using a lever system provides for the transmission of force by the lever system with variable transmission ratio. In this case, the setting piston is connected with a slide block which rests against the setting part on the one hand and against a lever on the other, whereby an end of the lever is supported by a piston subjected to the pump pressure. The second end bears against a spring-supported control slide (German printed application--Auslegeschrift--DT-AS No. 1 044 620). In this case as well, the fulcrum of the arm lever is movable.
In a kinematic reversal to the foregoing (see German open application--Offenlegungsschrift--DT-OS No. 2 003 774) the lever has one end fixedly hinged while the opposite end bears against a spring fixed in the housing. The control valve is provided in the piston rod of a piston which is shiftable approximately parallel to the lever. In this case disadvantages are also encountered which appear to result from the need to accommodate the control piston in the piston rod. A discussion of this point can be found in German Offenlegungsschrift DT-OS No. 2 017 656. See also the following German open applications--Offenlegungsschrifts--DT-OS No. 1 498 288 and No. 1 267 092.
Reference may also be had to German open applications--Offenlegungsschrifts--DT-OS No. 1 400 630 and DT-OS No. 1 425 756 which describe other control devices in which a lever system with a variable transmission ratio is employed. These systems are provided, in a manner not unlike that of the German printed application--Auslegeschrift--DT-AS No. 1 044 620, with a lever whose fulcrum is shiftable and having one end at which a spring acts. Here, however, the prestress and hence the reaction force of the spring is dependent upon the position of the setting piston and varies therewith. In this system all of the aforedescribed disadvantages of lever fulcrums which vary as to location (nonfixed lever fulcra) are encountered.

Control device for an axial piston machine


A grain dryer having a column with an interior wall, an exterior wall, an inlet and an outlet. The column has an upper heated pressurized plenum and a lower, low pressure, suction plenum. Attached to the interior wall within the column is a narrowing divider that increases the path of the heated air at the pressure gradient.

This invention is directed to a narrowing column divider and more particularly to a column narrowing divider for a continuous-flow grain dryer.
Continuous-flow grain dryers are well-known in the art for dryers 10 having a column 12 with a split plenum, as shown in FIG. 1, a lower suction plenum 24 pulls a portion of the upper heated air P from an upper heated pressurized plenum 22 which reduces the capacity and the amount of cooling of the dryer. Presently, in current dryers, there is no restriction to the pressure gradient within the grain column to reduce the waste of heated air. Therefore, a need exists in the art for a device that addresses these deficiencies.
An objective of the present invention is to provide a grain dryer that improves the efficiency of drying grain.
Another objective of the present invention is to provide a grain dryer that restricts airflow from wrapping around the plenum divider 25 within a column from a high pressure to a low pressure plenum.
A still further objective of the present invention is to provide a grain dryer that better utilizes heated air.
These and other objectives will be apparent to those of ordinary skill in the art based upon the following written description, drawings, and claims.

Column narrowing divider for a grain dryer


A new and improved dental floss having a relatively large diameter to provide an increased surface area, and comprised of a multitude of fibers overlaid upon each other such that a number of the fiber ends extend beyond the main body of the dental floss and are somewhat self-supporting. The dental floss has improved cleaning ability and increased shock absorbency which lessens discomfort to the user.

1. Field of the invention
Dental floss is a well-known toilet article used to promote dental hygiene by polishing the surface areas of the teeth and removing unwanted matter from the interproximal areas between the teeth. Typically, in use, a segment of dental floss is passed between the crowns of two adjacent teeth in order to dispose the dental floss in the interproximal space. When the teeth are spaced closely together, the user of dental floss must apply to the ends of the dental floss segment a significant amount of pressure in the direction of the gum. As the dental floss initially passes between the crowns of two closely-spaced teeth, the movement of the dental floss toward the gum is restricted by the two crowns, but as the user continues to work the dental floss past the adjacent crowns, a point is reached at which the teeth are not so closely spaced, and so the movement of the floss toward the gum is suddenly accelerated. When this point is reached, the typical user, and particularly an inexperienced user, is unable to react quickly enough, by releasing the pressure he is exerting, to slow the further movement of the dental floss toward the gum. The result is a sudden movement of the floss, with consequent sudden and forceful contact of the dental floss against the gum, which causes discomfort to the user and often bleeding from the gum. Actual gingival gum injury can result from this forceful action where the tautly stretched, smooth, narrow floss acts in a manner similar to a scalpel. When gingival gum tissue becomes inflamed in an unhealthy state, it swells, turns soft and spongey, and bleeds easily, thus offering less resistance to injury from this cutting effect. Gum disease is at epidemic proportions, and most users of dental floss, whether waxed or unwaxed, smooth or treated, are awkward in its use until they develop the necessary dexterity to prevent this sudden acceleration toward the gum tissue in the interproximal space between the teeth.
2. Description of the prior art
Heretofore, dental floss has been composed of such materials or in such a fashion that the effect of the sudden and forceful contact upon the user's gum has been a problem. The shock-absorbency of prior art dental floss has been insufficient, either due to failure to construct the floss of a shock-absorbing material or due to covering of a potentially shock-absorbing material with a hardened or waxy surface coating.
In addition, many flosses used today are relatively small in diameter, thereby increasing the effect of the forceful striking on a small area of the gum and correspondingly increasing the risk of more intense trauma to that particular area. Of the remaining flosses that have relatively large diameters, the effect of the striking contact is not significantly mitigated, either because alternate portions of the floss have small diameters or because the diameter of the floss is decreased when distended.
In addition to the discomfort caused by heretofore manufactured dental flosses, another disadvantage has been the insufficiency of cleaning capacity caused, at least in part, by the small diameter and the smooth surface of the dental floss. One attempted solution to improve these characteristics has been to manufacture dental floss of a wide, flat ribbon, but such solution has been inadequate due to the difficulty in adequately providing such floss with the preferred textured surface and due to inability to provide such floss with sufficient shock-absorbency. A second attempted solution has been to provide a fibrous floss that possesses an expanded surface area when the floss is not distended, but such solution is likewise inadequate because certain surface areas of the teeth are encrusted with hardened plaque that requires greater floss tension for removal, and when such tension is supplied, this floss becomes distended and its surface area is reduced.


A vehicle body structure includes a floor panel, a door frame, a cross-member, and a load transmittal bracket. The door frame and the cross-member are fixed relative to the floor panel. The door frame defines a door opening. The load transmittal bracket is disposed between the door opening and the cross-member. The load transmittal bracket includes a second segment welded to a first segment and to the floor panel. During a side impact of the vehicle, the load transmittal bracket transfers impact force from the door frame to the cross-member to dissipate the impact force and reduce deformation of the floor.

Vehicles, such as automobiles, include body structures to absorb energy during a vehicle impact, for example, a vehicle-to-vehicle impact. During the vehicle impact, components of the vehicle may deform to absorb energy. For example, the vehicle may include exterior panels, e.g., doors, fenders, etc., a body structure supporting the exterior panels, and a floor disposed below a passenger compartment of the vehicle. In the case of a side impact to the vehicle, the exterior panels may deform and impact the body structure. If the impact is of sufficient magnitude, the body structure may be forced into the floor and may cause the floor to deform.
The design of components of the vehicle body structure is subject to several constraints, such as packaging constraints, manufacturing constraints, vehicle assembly constraints, cost constraints, etc. There remains an opportunity to design a vehicle body structure that effectively absorbs and transfers energy in a manner that accommodates these design considerations.

Energy absorbing load transmittal bracket with weld accessibility


A radar based sensor detection system comprises a microwave source operative to provide a continuous wave signal at an output. A pulse-former is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator is coupled to the output of the pulse-former for providing a modulated pulse signal. A transmit receive switch coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel coupled to the transmit receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit receive switch receives the modulator signal when the switch is operated in the receive position. First and second voltage multipliers each have a local oscillator input for receiving the modulator signal in the receive position, and each have an input signal port, and an output port. A receiver channel receives a reflected transmitted signal from an output and applies the received signal to the receive signal input ports of the voltage multipliers. An autocorrelator coupled to the output ports of the voltage multipliers correlates the received signal to produce an output signal indicating the detection and position of the object.

This invention relates to a short-range pulse-compression radar system particularly suitable for fabrication as an integrated circuit.
A need exists for a short-range radar system, which, for example, is suitable for automotive and other commercial applications. Such a system would be enabled to sense the proximity of other vehicles and objects, moving or stationary, within a range radius of about 0.15 meters to 30 meters or beyond. Radar systems having automotive application have been proposed in the prior art, including systems utilizing radar for automatic braking, as well as warning the operator of the vehicle of an impending danger or obstruction such as an animal or person in the roadway.
In addition to object range detection, it is also useful to be able to distinguish or resolve the distance between two objects in very close proximity (e.g. when they are approximately 15 centimeters apart). An intelligent radar detection system comprises a number (one or more) of sensors that operate as a transceiver for electromagnetic energy. The sensors typically transmit and receive electromagnetic energy of a defined frequency and power via an antenna over a defined spatial area. In turn, the system receives echo signals from partial reflections of any illuminated objects in that area. The ability of the sensor to resolve two or more objects closely situated in the illuminated area leads to the descriptive name of high-resolution radar (HRR).
The prior art also refers to high range resolution mono-pulse radar systems which are designated (HRRM). See, for example, a text entitled, xe2x80x9cRadar Handbookxe2x80x9d, Second Edition, by Merrill Skolnik, published by McGraw Hill, Inc. (1990). This text gives descriptions of radar systems, including high-resolution systems. As one can ascertain, there is a large potential market for automotive radars as well as for other commercial applications. Such applications include, but are not limited to, automatic door openers, sanitary facilities, electronic boundary detectors or fences, electronic camera focusing, navigation devices, parking aid sensors, and a host of other potential uses. However, in order to create a system for such markets, a technical solution must be provided that is not only capable of operating with the required degree of performance, but also offers a potential route to lower cost sensors. The price reduction should be able to take advantage of economies of scale and other established high volume manufacturing techniques. In addition, the sensor architecture should be sufficiently flexible to offer multiple operating modes to enable varying application and custom requirements depending upon the intended end use.
The prior art was cognizant of the need for low cost, high-resolution radars. Reference is made to U.S. Pat. No. 6,067,040 entitled, xe2x80x9cLow Cost High Resolution Radar for Commercial and Industrial Applicationsxe2x80x9d, issued on May 23, 2000 to K. V. Puglia. The patent describes a low cost, high-resolution radar based detection system, which has a pulse repetition frequency generator connected to first and second narrow pulse modulators. The system employs a transmit channel which is connected to the first narrow pulse modulator and emits pulse modulator carrier based transmit signals having a prescribed frequency and a prescribed duration. The receive channel is connected to the second narrow pulse modulator. There is a time delay circuit which delays the output of the second pulse modulator to the receive channel and a mixer which mixes a portion of one of the pulse modulated carrier based transmit signals reflected from an object with the output of the second narrow pulse modulator.
PCT application entitled, xe2x80x9cSensor for Measuring a Distance from an Objectxe2x80x9d No. WO 00/43801 having a priority date of Jan. 20, 1999 and filed for Martin Reiche describes a sensor for measuring the distance from an object. The apparatus includes an oscillator which generates a carrier signal. A first modulation switch modulates pulses on a carrier signal and generates a first pulse signal. The first pulse signal is emitted in the direction of the object. The first pulse signal is reflected by the object and delayed by a propagation time. A power divider positioned between the oscillator and the first modulation switch transmits the carrier signal to a second modulation switch. The second modulation switch modulates the pulses on to the carrier signal and generates a second pulse signal that is delayed by a variable delay. One compares the delay of the second pulse signal with the propagation time of the first pulse signal to detect the propagation time and determine the distance to the object.
An aspect of the invention is to increase the pass-band transmission loss of the modulation switches by providing for a third modulation switch which is positioned between the oscillator and the power divider. As one can see from the above-noted techniques, the typical operating scenario presented in the above systems are based on a combination of discrete circuit components combined with distributed transmission line elements on a soft substrate. These prior art approaches can lead to a combination of manufacturing tolerance issues and operating scenarios that compromise the performance of the sensor. It is understood that the design and assembly of the sensor based on discrete components leads to a relatively large device. The functional operation of the sensors is restricted for both size and cross constraints as each additional circuit block is relatively expensive to add. The use of distributed transmission line circuitry is a common technique for the design of high frequency microwave and millimeter circuits, but is based on the fundamental assumption that standing waves are present in the circuit. This assumption no longer holds true under short pulse conditions, and can lead to transient and short-term circuit effects that reduce the operating margin and compromise sensor performance. Lastly, the mid- to long-range operation of the short pulse sensor is not optimum due to two issues. The energy received by the sensor from partial reflection of the detected objects varies as an inversely proportional function of the fourth power of the object""s range. As the range increases, the ability of the sensor to detect objects rapidly decreases as a function of the greatly reduced energy incident upon, and reflected from objects. Conventionally, there are two limitations that restrict the amount of energy (power) that may be transmitted by the sensor: the ability to discriminate between two targets (range discrimination) is a function of the pulse-length in pulsed-radar systems, and the chirp or frequency modulation bandwidth in a CW radar system. A longer pulse length increases the amount of energy transmitted by the sensor with a consequent reduction in the ability of the sensor to discriminate between closely located objects. Also, the interval between pulses (or pulse repetition frequency (p.r.f)) may not be reduced indiscriminately to increase the transmitted energy for the need to maintain an unambiguous range measurement. In addition, the sensor is susceptible to in-band interference sources that produce and transmit electromagnetic energy in the same portion of the electromagnetic spectrum as that of the sensor. The forms of the interfering sources include CW or pulsed transmission by other systems, mutual interference from a second sensor or sensor system operating with the same or similar purpose, self-jamming through imperfect isolation between the transmit and receive port antennae, and wide-band thermal noise.
Thus, one can readily understand that these problems increase with such sensor devices that are used in, for example, the automotive industry. For example, hundreds of cars on a single highway may all be generating and receiving signals operative in the same radar range or at similar frequency bands.
In accordance with an aspect of the present invention; a variable length pulse is introduced that increases the transmitted energy of a sensor at longer ranges. The superimposition of a short duration phase coding on the expanded transmitted pulse is used to maintain the required range resolution of the sensor for the instances of longer pulse duration. The phase coding is also useful in increasing sensor immunity to interference from other sources. In addition, by making the specific phase-code variable as a function of range, the p.r.f. of the sensor can be increased without compromising range ambiguity. Other circuit functions that supplement and enhance this process include varying the pulse repetition frequency of the transmit sequencexe2x80x94both over time and as a function of the range-gate under observation, adding frequency modulation to the local oscillator within the sensor and a variable gain amplifier used to control and vary the amount of energy transmitted at any instance by the sensor. The receiver of the sensor includes a two step pre-detection integration process to ensure that the reflected energy captured by the sensor is as large as possible at a given instant to maximize the likelihood of a correct detection decision.
The increased functionality of the sensor according to the present invention can be addressed while simultaneously considering the issue of manufacturability and cost. A system embodying an aspect of the present invention incorporates circuit functions into either a single transceiver integrated circuit (IC) or a dual IC chipset comprising a separate transmitter and receiver IC, or a combination thereof. The high integration capability of integrated circuit processes allows several circuit functions to be located in close proximity on a single chip. In addition, the reduced circuit size and interconnect distance between components allows circuits to be designed using conventional analog and lumped circuit theory. This technique eliminates the need for distributed circuit design that is not ideal for short pulse transient conditions. The circuit is preferentially designed using balanced circuit configurations to maximize common-mode noise rejection, although single-ended circuit designs are also possible. The integrated circuit process that is preferred for accomplishing enhanced operation and increased circuit density is a Silicon Germanium (SiGe) process that includes both bipolar transistors and CMOS transistors as part of the same circuit (BiCMOS). Other suitable technologies that are also considered useful are SiGe bipolar only processes; and III-V processes such as GaAs or InP based MESFETs, pHEMTs, or HBT devices. It is understood that such integrated circuit techniques can be employed because of the system architecture and because of the way the system is implemented using a variable pulse length that basically increases the transmitted energy of the sensor at longer ranges.
An improved short-range radar system suitable for automotive and other short-range commercial applications for sensing the proximity of vehicles or objects within a radius ranging from about 0.1 meters to about 30 meters and beyond.
An aspect of the present invention is embodied in a system architecture for a short-range radar system which is capable of being implemented utilizing conventional integrated circuit techniques.
A further aspect of the present invention is the use of variable length phase codes whose code length may be varied as a function of range to provide increased immunity to interference sources; the ability to transmit longer pulses with a short-phase code to maintain short-range discrimination, and the ability to use the variable length code as a means of maintaining a relatively high p.r.f. compared to conventional radar sensors while still maintaining a high unambiguous range.