A light source device for endoscopes includes a light source; a condenser lens unit for collecting light beams from the light source; a light guide for receiving the light beams collected through the condenser lens unit into its entrance end face to transmit them to its exit end face; and a reflecting mirror located on the opposite side of the condenser lens unit with respect to the light source. The light source device is designed so that a position where the light beams emitted from the light source are collected directly through the condenser lens unit does not coincide with a position where the light beams emitted from the light source and reflected back to the light source by the reflecting mirror are collected through the condenser lens unit.

1. Field of the Invention
This invention relates to a light source device for endoscopes which is compact in design, keeps a loss of the amount of light to a minimum, and affords low cost and small power consumption, and in particular, to a light source device for endoscopes which is used in an endoscope observation system and, even with use in an endoscope having a plurality of light guides of different numerical apertures, is capable of changing the numerical aperture of an incident light beam in accordance with the numerical apertures of the light guides.
2. Description of Related Art
Endoscopes at present are widely used in which the internal organs are observed by inserting an elongation of the endoscope in the human body, and a treatment tool inserted in a channel therefor is used when necessary, to make various treatments.
Endoscopes are roughly divided into two classes: "fiberscopes" in which visual observation is made and "electronic scopes" in which a solid-state image sensor, such as a CCD (charge coupled device), is used as image pick-up means. In particular, the latter endoscopes have been frequently used in recent years.
The illumination means of the endoscope is generally constructed with a light source device; a light guide for transmitting light supplied from the light source device to the distal end of the endoscope; and an illumination lens incorporated in the distal end of the endoscope, for spreading the light emerging from the light guide to radiate toward an object.
FIG. 1 shows an optical arrangement of a conventional light source device for endoscopes. This light source device includes a light source 1 emitting white light; filters 2 for selectively blocking rays having particular wavelengths of infrared and ultraviolet rays, of white light emitted from the light source 1 (namely, total infrared blocking filters for removing infrared rays); a condenser lens system 3 for collecting beams of light transmitted through the filters 2; and a light guide 4 for receiving the light beams collected by the condenser lens system 3 into its entrance end to transmit them to its exit end. The optical system of this light source device is designed so that the image of the bright spot of a source lamp 1a is projected on the entrance end face of the light guide 4.
In general, a xenon lamp is frequently used for the light source 1 of the light source device for endoscopes of this type, and the source lamp 1a is constructed integral with a reflecting mirror 1b. The bright spot of the source lamp 1a is condensed at the position of the focal point of the reflecting mirror 1b so that reflected light by the reflecting mirror 1b becomes nearly parallel beams.
Illumination beams transmitted through the filters 2 are collected by the condenser lens system 3, and recently, for the purpose of compactly constructing the entire light source device for the purpose of reducing the manufacturing cost, a single lens in which at least one of its lens surfaces is configured to be aspherical has been chiefly used for the condenser lens system 3. It is for this reason that, in order to efficiently condense the illumination beams from the source lamp 1a through the condenser lens system 3 on the entrance end face of the light guide 4, an aspherical lens needs to be used to correct spherical aberration and coma. In this case, the aspherical lens has a convex surface of such a shape the curvature is large in the vicinity of the optical axis of the lens and reduces progressively in separating from the optical axis.
For the illumination light source of the light source device for endoscopes, a halogen lamp, in addition to the xenon lamp, is used, and it is a common practice that the halogen lamp is constructed to be integral with an elliptical mirror. FIG. 2 shows the arrangement of such a light source device. Beams of light emitted from a halogen lamp 5a are condensed on the entrance end face of the light guide 4 by an elliptical mirror 5b, and thus the condenser lens system is dispensed with.
The xenon lamp of high luminance, however, is expensive in itself, and in general requires power consumption as high as 300 W, which is economically disadvantageous. Furthermore, a power supply for turning on the xenon lamp and a cooler are bulky. Hence, where the xenon lamp is used, the light source device for endoscopes also becomes large-sized and expensive.
On the other hand, because of the improvement of endoscope technology and the variety of application of the endoscope in recent years, the endoscope itself tends to a reduction in diameter. In keeping with this, the entrance end on the light source side of the light guide 4 also exhibits a tendency toward the reduction of diameter. In order to meet this situation, one lens surface of the condenser lens system 3 is provided with a high power to diminish the focal length as far as possible and a beam diameter on the condensing face is reduced so that a sufficient amount of light can be supplied to the light guide of reduced diameter.
However, with the developments of an endoscope apparatus and its manipulation, the following desires have recently been increased.
(1) When a 300 W xenon lamp of high luminance, which is high in cost and large in power consumption as stated above, is used in the light source device for endoscopes, it is very disadvantageous for the cost and power consumption of the device, and the device becomes large in size. Thus, a light source device for endoscopes is required which holds the brightness of illumination light usable even for the manipulation, affords low cost and small power consumption, and is compact in design. In order to fulfil these requirements, it is necessary to use an illumination lamp of low cost and small power consumption, such as a halogen lamp or a metal halide lamp.
(2) Recently, there is a growing tendency that the diameter of the insertion of the endoscope becomes small, and a light guide used in such an endoscope requires the diameter to be made smaller without decreasing the amount of transmission light. In order to satisfy this requirement, it becomes necessary to increase the numerical aperture of the light guide to improve the transmission capacity of light.
For point (1) mentioned above, however, the luminance of the halogen lamp is considerably lower than with that of the xenon lamp, and thus it is difficult for the halogen lamp to bring about illumination light of brightness required for the manipulation. Moreover, in the halogen lamp, the efficiency of conversion of an input power into visible light is as low as 10%. Hence, a sufficient amount of light cannot be obtained. Further, since the remaining 90% is converted into heat, a large-sized, expensive cooler is required. In the case of the metal halide lamp, on the other hand, since the efficiency of conversion of the input power into visible light is high, a lamp of low rated power consumption is satisfactory and does not produce heat so copiously as to cause trouble. As such, a small-sized, inexpensive cooler is used. However, the metal halide lamp is lower in luminance than the xenon lamp and is difficult to secure a fair amount of light.
As means for increasing the amount of light, it is considered that a lamp of high rated power consumption is used. In this case, however, the amount of emitted light is increased because the light emitting section of the lamp is enlarged, but that alone will not improve the luminance of the light emitting section. Thus, in the case where light is made incident from such a lamp on the light guide of small diameter, when a power supplied exceeds a certain value, little brightness is improved even though the power is made higher. In this way, an increase in rated power consumption of the lamp causes useless oversizing of the light source device and the cooler, which is unfavorable.
Consequently, in order to bring about the light source device for endoscopes which affords low cost and small power consumption and is compact in design, it is necessary that a lamp of small power consumption and low cost be used and light emitted from this lamp be made effectively incident on the light guide.
As for point (2), where the light guide of small numerical aperture which has been used in the past is used in the device in which the focal length of a condensing optical system is set so as to correspond to the light guide of larger numerical aperture, the amount of light incident on the light guide suffers a great loss.
In order to solve this problem, as set forth in Japanese Patent Preliminary Publication No. Hei 3-118509, it is known that the numerical aperture of emitted light of the condensing optical system can be changed in accordance with that of the light guide. However, that the optical system is constructed with a zoom system as the above means results in serious complication of the optical system, and causes an increase in the number of lenses and a loss of the amount of light as well. Furthermore, the entire length of the optical system is increased, and oversizing of the light source device itself is brought about.
The conventional device, as shown in FIG. 3, has met the problem in such a way that, in order to secure incident light of the numerical aperture most suitable for light guides of small and large numerical apertures, two light sources 1 are used to form separate optical paths, in which condenser lenses 3 and 3' are arranged. In this case, the use of two lamps causes oversizing of the entire light source and increases power consumption, resulting in false economy. Additionally, since the production of heat in the entire light source is increased, a large-sized cooler is required. As a consequence of this, the light source device is enlarged and becomes costly.


A drill fitted to an adapter is used to drill a hole in a workpiece fixed on a table of a machining center. When the hole drilling is finished, the drill is removed from the adapter, and a workpiece holding jig is fitted to the adapter. Then, the adapter is lowered, and the workpiece holding jig takes the workpiece for which the hole drilling operation has been finished. Following this, the adapter is raised, and the workpiece is temporarily held in the machining center. Then, in this state, the next workpiece is mounted on the table of the machining center. Accordingly, by temporarily holding the workpiece, for which the hole drilling operation has been finished, in the machining center, mounting of the next workpiece is simplified.

1. Field of the Invention
The invention relates to a machining apparatus for machining a workpiece, to a general-purpose apparatus, e.g., a "machining center", that performs a variety of different types of machining operations by switching between various machining tools, and to a production line provided with a plurality of machining apparatuses.
2. Description of the Related Art
Conventionally, a production line for automatic transmissions (hereinafter referred to as "A/T" or "A/Ts") includes a machining line with plural machines for machining various types of workpieces, namely, components of the A/T. This machining line includes a plurality of machining centers (hereinafter referred to as "M/C" or "M/Cs") that are arranged in a line and a robot that mounts and removes the workpieces to/from the table of each M/C. Further, the same type of machining line is also utilized in production lines for devices and machines other than A/Ts.
An example of a machining line provided with a plurality of M/Cs and a robot is described in Japanese Patent Laid-Open Publication No. 2001-255922 as having three M/Cs positioned in a straight line and a single robot that travels along the line of M/Cs for mounting and removing respective workpieces to/from the tables of the M/Cs.
In the machining line disclosed in Japanese Patent Laid-Open Publication No. 2001-255922, the robot removes an unmachined workpiece from a workpiece carrying device, and following mounting of the unmachined workpiece on a table of a first M/C, the first M/C machines the workpiece. Next, the robot removes the workpiece (the machining of which has been finished at the first M/C) from the table of the first M/C, and carries it to a second M/C that performs the next machining step. The workpiece is then mounted on the table of the second M/C where it is further machined by the second M/C. Then, the robot removes the workpiece (the machining of which has been finished by the second M/C) from the table of the second M/C, and carries it to an nth M/C that performs the next machining step. The workpiece is then mounted on the table of the nth M/C, and the nth M/C performs another machining step. Lastly, the robot removes the workpiece (after completion of machining by the nth M/C) from the table of the nth M/C, and then another workpiece carrying device carries the workpiece away. In this way, the machining processes of the first to nth M/Cs are performed in sequence on the workpiece.
However, with the above-described machining line disclosed in Japanese Patent Laid-Open Publication No. 2001-255922, the robot does not return to the first workpiece carrying device (carrying-in device) until the machining of a given workpiece has been finished by the nth M/C. Accordingly, while a given workpiece for which machining has been completed by the first M/C is being processed by the second M/C, it is not possible to mount another workpiece in the first M/C. As a result, machining of the next workpiece cannot be performed by the first M/C. In addition, similarly, while a given workpiece that has been finished by the second M/C is being further machined by the nth M/C, it is not possible to mount successive workpieces in the first and second M/Cs. Accordingly, machining of the successive workpieces cannot be performed by the first and second M/Cs. Thus, there is substantial wasted time in the operation of this machining line, and the machining operations are not performed efficiently. Thus, a long time is required for the completion of machining of a given number of workpieces.
In order to address these problems, it would be possible to modify the machining operation of the machining line disclosed in Japanese Patent Laid-Open Publication No. 2001-255922 such that, following transfer of a given workpiece that has been finished at the first M/C to the second M/C, the robot moves back to the carrying-in device and removes an unmachined workpiece therefrom, mounts it on the table of the first M/C, and then carries the workpiece, for which machining has been finished at the second M/C, to the nth M/C, and mounts it therein. Following carrying to the nth M/C in the above mentioned manner, the robot could be made to travel back to the first M/C so as to remove the workpiece for which machining has been finished, to carry the workpiece to the table of the second M/C, and to mount it thereon. The robot could then be made to travel back to the carrying-in device and remove another unmachined workpiece therefrom, and to mount this workpiece on the table of the first M/C. In addition, similar robot operational control could be executed when a given workpiece finished at the nth M/C is carried to the carrying-out device by the robot. However, if robot operation control were to be executed in this manner, the robot would be subjected to repeated forward-and-backward movements between the carrying-in device, the first, second and nth M/Cs, and the machined workpiece carrying-out device. Accordingly, there would still be substantial wasted time in the machining operation.
Moreover, the process requires the robot to execute mounting and removal of the given workpieces for each M/C, as a result of which the workpiece mounting and removal operations are complicated. In addition, the robot is required to execute a sequence of operations, namely, mounting the workpiece, removing the workpiece and movement along the M/C line. Accordingly, the robot operation control becomes complicated and cumbersome.
FIG. 7 illustrates a machining line 1 including a predetermined number n (n≧2) of M/Cs arranged in a line, and temporary workpiece stations respectively located between the M/Cs. More specifically, the machining line 1, includes a first M/C 2, a second M/C 3, an nth M/C 4, an unmachined workpiece placement station (hereinafter referred to as "workpiece station") 6, a first M/C post-machining temporary workpiece station 7, a second M/C pre-machining temporary workpiece station 8, a second M/C post-machining temporary workpiece station 9, an nth M/C pre-machining temporary workpiece station 10, a completed workpiece station 11, a robot 13, and a guide rail 14.
The robot 13 is, for example, a conventional articulated arm robot. As shown in FIG. 7, the robot 13 is provided with a main body 13a and a first arm 13b connected to the main body 13a for horizontal rotation and raising and lowering relative to the main body 13a. A second arm 13d at one end carries a workpiece holder and is telescopically connected to the first arm 13b for retraction and extension relative thereto. Similar to the structure shown in FIG. 4(a) (described hereinafter), the workpiece holder is connected to the second arm 13d so as to allow relative rotation around an axis that is perpendicular to the view in FIG. 7.
Accordingly, the workpiece holder 13c is capable of movement upward and downward, left and right, and forward and backward, within ranges of movement of the first and the second arms 13b and 13d. Further, the workpiece holder 13c is maintained in a substantially horizontal position with movement of the first and second arms 13b and 13d, through use of a conventional mechanism. Of course, the robot 13 is not limited to the above described configuration, and any robot that can be utilized in the machining line 1 and which is capable of mounting and removing the workpiece 5 to/from the respective M/Cs 2, 3 and 4, may be used. The robot 13 is mounted for movement along the guide rail 14 along which each of the M/Cs 2, 3 and 4 is positioned.
Next, the operation of the machining line 1 shown in FIG. 7 will be explained. First, the workpiece 5, is carried to the workpiece station 6 in the vicinity of the first M/C 2 and placed thereon. Then, the main body 13a of the robot 13 is moved to a predetermined position that corresponds with the first M/C 2, and the first and second arms 13b and 13d are moved to retracted positions. Then, the robot 13 is activated and the first arm 13b is appropriately rotated in a horizontal plane and appropriately vertically positioned. Moreover, the second arm 13d is appropriately extended-retracted relative to the first arm 13b. As a result, the workpiece holder 13c is positioned, as shown by the dot-dash line, at the workpiece station 6.
The workpiece holder 13c holds the workpiece 5 at the workpiece station 6, and then the first and second arms 13b and 13d operate to move the workpiece holder 13c to the position indicated by the solid line. At this time, the workpiece 5 held in the workpiece holder 13c is moved to a fixing point 2k on top of a table of the first M/C 2 where it is fixed to the table. Following this, the first and second arms 13b and 13d are retracted back to their original positions.
The workpiece 5 on top of the table of the first M/C 2 is fixed thereto by a clamping device (not shown), and the first M/C 2 is operated to perform a first machining operation on the workpiece 5. When the first machining of the workpiece 5 is finished, the clamping device releases the workpiece 5. Then, both arms 13b and 13d of the robot 13 are operated to grasp the workpiece 5 with the workpiece holder 13c, to remove the workpiece 5 from the table of the first M/C 2, and to then temporarily place the workpiece at the first M/C post-machining temporary workpiece station 7 as indicated by the dot-dash line in FIG. 7. Next, both arms 13b and 13d of the robot 13 are moved back towards the workpiece station 6, and once the workpiece holder portion 13c has grasped the next workpiece 5 at the workpiece station 6, in a similar manner as before, and places it on top of the table of the first M/C 2. Then, the next workpiece 5 is fixed to the table of the N/C 2, and the first machining operation is again executed.
Next, the robot 13 grasps the workpiece 5, for which the first machining has been completed and which has been temporarily placed at the first M/C post-machining temporary workpiece station 7. Then, the main body 13a of the robot 13 moves toward the second M/C 3 while guided by the guide rail 14, and the workpiece 5, for which the first machining has been completed, is temporarily placed on the second M/C pre-machining temporary workpiece station 8, as shown by the dot-dash line. The robot 13 then stops at a predetermined position that corresponds with the second M/C 3 (the position indicated by the solid line in the middle of FIG. 7). Next, in a similar manner as before, the robot 13 grasps the workpiece 5, for which the first machining has been finished and which is at the second M/C pre-machining temporary workpiece station 8, and places the workpiece 5 on the table of the second M/C 3.
As before, the workpiece 5, for which the first machining has been finished is fixed to the table of the second M/C 2, and then a second machining is performed. When the second machining is finished by the second M/C 3, the robot 13 takes the workpiece 5 and temporarily places it on the second M/C post-machining temporary workpiece station 9. Then, the robot 13 moves again to the predetermined position (the solid line shown to the left-hand side of FIG. 7) corresponding to the first M/C 2. Then, as before, the next workpiece 5 for which the first machining has been finished is taken and temporarily placed on the first M/C post-machining temporary workpiece station 7, and yet another workpiece 5 is taken from the workpiece station 6 and placed on the table of the first M/C 2. Following this, the robot 13 moves and takes the workpiece 5, for which the second machining has been finished and which is on the second M/C post-machining temporary workpiece station 9, and temporarily places it on the nth M/C pre-machining temporary workpiece station 10.
Following this, in the manner described above, the robot 13 continues to execute the transport, mounting and removal operations with respect to each of the M/Cs 2, 3 and 4, and the M/Cs 2, 3 and 4 repeatedly perform their respective machining operations. When the nth machining by the nth M/C 4 is finished, the robot 13 takes the workpiece 5 from the nth M/C 4, and places it on the completed workpiece station 11, as a machined part 12. This machined part 12 is then carried to the next work station by a suitable device. It should be noted that it is possible to integrate the respective neighboring M/C post-machining temporary workpiece stations and the M/C pre-machining temporary workpiece stations (for example, those indicated by reference numerals 7 and 8) into a single common workpiece temporary placement point.
In the mounting and removal operations for of the workpiece 5 executed by each M/C, it is sufficient for the robot 13 to control operation of the arms 13b and 13d, and there is no need for the robot 13 to control movement of its main body 13a. Accordingly, the robot control is made correspondingly simpler.
However, even with the machining line 1 shown in FIG. 7, mounting and removal of the workpiece 5 by the robot 13 must be executed for each M/C, and thus the mounting and removal operations of the workpiece 5 are complicated.
Moreover, when the machining of the workpiece 5 by one M/C is finished, the robot 13 takes the workpiece 5 and temporarily places it at a temporary placement station. Following this, the robot 13 moves it to the neighboring M/C which is next in line in the upstream direction, and when the machining of this M/C is finished, temporarily places the workpiece 5 at the respective temporary placement station. The robot 13 progressively moves in sequence, in the processing flow upstream direction, while executing similar operations. However, after a new workpiece 5 is mounted in the first M/C 2, the robot 13 must travel to the M/C of the machining line 1 at which the workpiece 5 that has progressed furthest in the machining is located, i.e., where the far-end workpiece 5 is located. When this far-end workpiece 5 has been machined by the nth M/C 4, the robot 13 must travel to the nth M/C 4. Accordingly, the robot 13 must repeatedly move forward and backward and, thus as with the conventional apparatus, there is substantial wasted time in the machining operation, making the machining operation less efficient.
Further, because it is necessary to provide the temporary placement points for the workpiece 5 between each M/C, these temporary placement points must be taken into account in design of the machining line 1, unavoidably making it larger.

Machining apparatus and machining line provided with same


Provided is a fiber grating laser for optical communication which can be used as a light source regardless of the occurrence of mode hopping. The laser module comprises a semiconductor optical amplifier device, an optical waveguide such as an optical fiber, and a diffraction grating such as a fiber grating. The semiconductor optical amplifier device has first and second end surfaces. The optical waveguide is optically coupled to the semiconductor optical amplifier device. The diffraction grating is optically coupled to the optical waveguide. The semiconductor optical amplifier device and the diffraction grating constitute an external cavity. An optical cavity length of the external cavity is in a range of 13 millimeters or more but 27 millimeters or less.

1. Field of the Invention
The present invention relates to a laser module for optical communication.
2. Related Background of the Invention
A fiber grating laser is described in the following literature, which discloses the related art in this field: "Technical Report of IEICE, EMD2002-24, CPM2002-66, OPE2002-46, LQE2002-101 (2002-08), The Institute of Electronics, Information and Communication Engineers." This fiber grating laser does not include a peltier element and is therefore a non-temperature controlled type device. The fiber grating laser exhibits temperature dependency of a wavelength and electric-current dependency thereof which are superior to those of a distributed feedback (DFB) semiconductor laser. An oscillation wavelength of the fiber grating laser is defined by a correlation between a longitudinal mode of an external optical cavity, which is constituted by a semiconductor optical amplifier device and a fiber grating, and a reflection characteristic-of the fiber grating. As shown in FIG. 2 of the literature, the fiber grating laser is configured to include at least one longitudinal-mode line within a reflection bandwidth of the fiber grating. Moreover, as shown in FIG. 4 of the literature, the fiber grating laser is small in size.


A device for taking samples from containers includes: a receiving body for at least one container; a container bar code reader positioned in the receiving body for containers; a support for a test tube with the ability to move; a bar code reader positioned in the support; and a fluid communication component between the container and the test tube. The support for test tubes includes at least a test tube loading position and a sample-taking position. The device also includes a controller configured to control position of the support for test tube. The controller can also include at least one sensor of the position of the support for test tube and a blocking component configured to block a position of said support for test tube.

The present disclosure relates to a device for taking samples, in particular, the present disclosure relates to a device for sampling collection containers (e.g. bottles of plasma) by means of test tubes for vacuum-extraction of samples.
At present, various devices exist for taking samples, including some completely automatic systems such as the device disclosed in European patent EP 2209007, for example. This device comprises a housing for containers, an input housing for multiple test tubes and the device is loaded automatically by taking each of the tubes, labelling them, taking the samples and placing the sealed, labelled test tube containing the sample at one of the outputs thereof.
These devices are technically complex with a wide variety of position sensors, cameras, image recognition systems and other peripheral devices that are required to ensure correct transfer of the fluids from the container to the test tube. This technical complexity and the need for coordination between the various peripheral devices result in this device being of considerable size and, in addition, requiring staff who specialise in robotic equipment to maintain them properly as well as providing technical support for the user personnel.

Device for taking samples from containers


In an example, a thermal extraction apparatus includes: a housing having a gas inlet and a gas outlet to receive a gas flow through the housing from the gas inlet to the gas outlet, and a side opening to receive a sample collector, having a sample collector adsorbent containing a vapor sample, into a sample collector location; a pump to generate the gas flow; a heater to heat the sample collector adsorbent of the sample collector to a temperature sufficient to release the vapor sample; a thermal desorption (TD) tube connected with the gas outlet of the housing to receive the gas flow downstream of the sample collector and collect the vapor sample released from the sample collector adsorbent of the sample collector; and a cooling member in heat exchange with the TD tube to cool the TD tube.

Sampling devices, specifically those used to screen large number of people or items, have been used for some time. These devices can be found almost anywhere, including government-run office buildings and airports. For example, airports use body scanners, utilizing machines that allow security officers an unobstructed view of a person's body to determine the presence of weapons. Other methods test for less visible items or substances, such as explosive residue or narcotics. Specifically, much focus has been put towards detection methods for these less visible substances as terrorism has risen, inasmuch as explosives, biochemical weapons, and the like threaten the security of the United States.
Liquid preparations have been used in detection methodologies. For example, a liquid is first applied to a surface to solvate or otherwise place into liquid phase the substance of interest which may be residing on the surface. Then, that mixture is tested. While such sampling devices are reliable, they suffer from many disadvantages, one of which is efficiency. Generally, in high volume situations it would take too much time to prepare liquid samples for every surface requiring testing.
Some detection systems require encapsulating the entire object, the surfaces of which require sampling. These systems involve large chambers, and therefore require a large footprint in which to operate. Handheld sampling wands also exist. However, many of these wands are tethered to stationary detection units, thereby hindering an operator's movement when climbing over parcels and crates. Other detection systems include vapor deposition systems whereby adsorbents sequester vapors containing target moieties. Such systems often do not allow for simultaneous extraction and sequestration of solid phase and/or liquid phase samples.
U.S. Pat. No. 8,578,796 to Cho discloses a device for sampling surfaces for the presence of compounds, including a housing having a proximal end adapted to receive a negative pressure gradient and a distal end adapted to contact the surfaces; a heating element spaced from the distal end; a primary filter spaced from the heating element; and a secondary filter spaced from the primary filter, the secondary filter removably received by the housing. A method for sampling a surface for the presence of compounds includes contacting the surface to dislodge the compounds from the surface; capturing first fractions of the compounds with a primary filter while allowing second fractions of the compounds to pass through the primary filter; heating the primary filter to volatilize the first fractions; capturing the volatized first fractions and the second fractions with a secondary filter; and analyzing the secondary filter to identify the compounds. The detection system is portable or stationary, light weight, and low cost. It utilizes off the shelf componentry, is capable of simultaneous sequestration of multi-phases of target compounds, and allows continued sequestration of target compounds in the field by facilitating in situ replacement of full sample carriers with empty ones.

Thermal extraction apparatus with high volume sampling trap

The Government of the United States of America, as represented by the Secretary of Homeland Security


A variable capacitor includes a first metal layer. The variable capacitor further includes a deoxyribonucleic acid-based (DNA-based) biopolymer layer including an organic component and a surfactant. The DNA-based biopolymer layer is adjacent the first metal layer. The variable capacitor further includes a conjugated polymer layer adjacent the DNA-based biopolymer layer and a second metal layer adjacent the conjugated polymer layer.

Varactors, or variable capacitors, are very useful for radio frequency (RF) applications by creating a device whose capacitance can be varied. Thus, the device may be used for tuning and impedance matching, increasing the efficiency and performance in RF systems. These devices can be made with a variety of materials and have many different topologies, but usually have a change in capacitance due to an applied DC voltage. In making RF varactors, a common topology allowed for relatively easy fabrication, testing, and integration with other RF components, and could be used with a variety of materials. The materials that were used traditionally included a single one component, such as barium titanate, poly methyl methacrylate (PMMA), or deoxyribonucleic acid hexacetyltrimethyl-ammonium chloride (DNA-CTMA).
However, prior art varactors are often limited to implementation on rigid substrates. Additionally, prior art varactors may have a somewhat limited range of optical and electrical design ranges.
Therefore, there exists a need for flexible varactor materials that may be configured for use on substrates such as plastic or other resilient planes. Further, there exists a need for varactor materials that may be synthesized to have desired optical and electrical properties.

The United States of America as represented by the Secretary of the Air Force


A positioning control system for performing recording/reproducing operations by irradiating an optical beam to a predetermined position on an optical recording medium, e.g., magneto-optical disk. The control system includes a photo-detector constituted by at least two-divisional units, and a servo-error signal generating circuit which can generate at least one servo-error signal in accordance with a difference between the detection currents. Preferably, the servo-error signal generating circuit includes at least one division circuit that has two pairs of transistors, two emitters in each pair of transistors being connected together into a common emitter, bias voltages of a direct current type being applied to the respective bases of transistors on one side, and the respective collectors of the transistors on one side being connected to a common connecting portion via resistors. The common connecting portion is connected to a power supply, and the respective bases of transistors on the other side are connected together into a common base. An integrating capacitor which integrates a difference between the current flowing through the common connecting portion and the reference current, is connected to the common base of the transistors on the other side.

1. Field of the Invention
The present invention relates to a positioning control system, which includes a tracking servo contro l and a focusing servo control utilizing an optical beam in a magneto-optical disk device, an optical disk device, an optical card, or the like, and which enables a desired track position, etc., to be accurately determined.
More specifically, the present invention relates to a positioning control system including a servo-error signal generating circuit, which can generate servo-error signal in accordance with a detection current output from at least one photo-detector for detecting the return optical beam reflected from a magneto-optical disk device, etc., so as to accurately irradiate a given optical beam to the desired track position(just focus position), etc., for recording/reproducing operations.
2. Description of the Related Art
In general, in a magneto-optical disk device, an optical disk device(sometimes including a magneto-optical disk device), or the like, recording/reproducing operations corresponding to write/read operations can be easily performed by utilizing an optical beam without necessity for complex mechanical elements such as a magnetic head, unlike a magnetic disk drive, a magnetic tape apparatus, or the like. Therefore, the former magneto-optical disk device, etc., can have a larger storage capacity than the latter magnetic disk device, etc. However, the magneto-optical disk device, etc., is likely to have difficulty in positioning a given optical beam to the desired track position, etc.
In regard to the positioning control system of such an optical beam, two kinds of control operations are performed: one is a tracking servo control which enables the track following operations on an optically recording medium such as a magneto-optical disk to be performed; and the other is a focusing servo control which enables a focusing position of the optical beam on the optically recording medium to be determined.
These control operations are executed in the following sequences:
First, the return optical beam, which is reflected from the optically recording medium, is detected by a plurality of photo-detectors in two-divisional configurations or in four-divisional configurations; and
Second, a tracking servo-error signal used for tracking servo control and a focusing servo-error signal used for focusing servo control are simultaneously taken out by utilizing the respective photo-detectors.
In this case, to assure the servo control operations in the magneto-optical disk device, etc., by utilizing an optical beam only, it is necessary to provide a servo-error signal generating circuit which generates each of the above-mentioned servo-error signals adjusted to have a constant amplitude. Such an adjustment of each of the servo-error signals is usually achieved by executing an automatic gain control(AGC) for the servo-error signals on the basis of the detection current output from each of the photo-detectors. Such a servo-error signal generating circuit including AGC circuit portion is generally constituted by a lot of electronic components, such as transistors and resistors. Therefore, a positioning control system having the servo-error signal generating circuit in a magneto-optical disk device, is likely to be large in size and expensive. To avoid this disadvantage, these electronic components are desired to be incorporated into an integrated circuit (IC), which can provide a desired circuit with a small size and in relatively low cost for fabrication.
Here, to enable a problem regarding a conventional positioning control system utilizing an optical beam to be understood more clearly, a concrete configuration of a positioning control system according to a prior art will be described with reference to the related drawings of FIGS. 1(A), 1(B), 1(C), 2 and 3. In this case, a positioning control system in a magneto-optical disk device will be illustrated representatively.
FIGS. 1(A), 1(B) and 1(C) are diagrams for explaining servo control operations for positioning control in a magneto-optical disk device. To be more specific, FIG. 1(A) is a perspective view schematically showing the whole construction of a magneto-optical disk device; FIG. 1(B) is a front view of each of photo-detectors of two-divisional type; and FIG. 1(C) is a front view of a photo-detector of four-divisional type.
In FIG. 1(A), 10 denotes a magneto-optical disk 10 which functions as an optically recording medium and which is rotated by a spindle motor(not shown). Further, 2 denotes an optical head 2 which irradiates an optical beam to the predetermined position on the magneto-optical disk 10 for recording/reproducing operations. The optical head 2 is adapted to be driven by another motor(not shown) so as to move with respect to the radial direction of the magneto-optical disk 10, and to perform a seek operation for the predetermined track position.
In regard to the configuration on the surface of the magneto-optical disk 10, a plurality of tracks for recording information are formed between adjoining guide grooves. Further, both a tracking position-error and a focusing position-error are obtained by utilizing the reflected optical beam, which is reflected from the magneto-optical disk 10 and goes back to an optical head 2 when an optical beam of the optical head 2 is irradiated to the magneto-optical disk 10.
To be more specific, a tracking position-error signal TES is generated on the basis of the reflected optical beam, and the tracking position-error of the optical beam corresponding to such a tracking servo-error signal TES is output. Further, taking into consideration the tracking position-error, a track control circuit(not shown) is adapted to control the optical head 2 to accurately irradiate the predetermined track for recording/reproducing operations.
In a similar manner, a focusing servo-error signal FES is generated on the basis of the reflected optical beam, and the focusing position-error of the optical beam corresponding to such a focusing servo-error signal FES is output. Further, taking into consideration the focusing position-error, a focusing control circuit(not shown) is adapted to control the optical head 2 so that a focus of the optical beam can accurately conform to the desired track position.
Further, in the optical head 2, the beam emitted from a semiconductor laser 20 is collected by a collimator lens 21. Then, the collected beam is reflected by a reflection mirror 23, through a beam-splitting prism 22 for splitting the beam into a polarized beam, and collected by an objective(also referred to as an actuator) 24, and irradiated to the surface of the magneto-optical disk 10,.
At this time, the magnetizing force is given to the irradiated track of the magneto-optical disk 10 by a magnet 30 which is arranged confronting with the magneto-optical disk 10, and write/read/erase operations on the predetermined track of the magneto-optical disk 10 can be performed.
Further, the reflected optical beam from the magneto-optical disk 10 is collected by the objective 24, and reflected by the beam-splitting prism 22, through the reflection mirror 23. Further, the reflected optical beam from the prism 22 is collected by another collimator lens 26, through a half-wavelength plate 25, and irradiated to both of a tracking photo-detector 29 of two-divisional type and focusing photo-detector 28 of two-divisional type, through another beam-splitting prism 22.
The tracking photo-detector 29 of two-divisional type are constituted by two divided portions so that the moving amount of the optical beam (the hatched portion in FIG. 1(B)) with respect to the radial direction of the track on the surface of the magneto-optical disk 10 can be detected, as shown in FIG. 1(B). Further, in FIGS. 1(A) and 1(B), the respective output terminals of the two divided portions of the tracking photo-detector 29 are connected to a tracking servo-error signal generating circuit 4a. Further, the tracking servo-error signal generating circuit 4a calculates the value of difference between the respective detection levels A, B of the two output terminals of the tracking photo-detector 29, and consequently outputs the tracking servo-error signal TES corresponding to this calculated value of difference.
Further, as shown in FIG. 1(B), the focusing photo-detector 28 of two-divisional type are also constituted by two divided portions. The respective output terminals of the two divided portions of the focusing tracking photo-detector 28 are connected to a focusing servo-error signal generating circuit 4b. Further, the focusing servo-error signal generating circuit 4b calculates the value of difference between the respective detection levels C, D of the two output terminals of the focusing photo-detector 29, and consequently outputs the focusing servo-error signal FES corresponding to this calculated value of difference.
As described above, in the example of FIG. 1(B), two kinds of photo-detectors 28, 29 of two-divisional type are utilized for detecting the tracking position-error and the focusing position-error.
However, as shown in FIG. 1(C), it is also possible for one photo-detector of four-divisional type to be utilized, in place of the two photo-detectors of two-divisional type as in FIG. 1(B). In this case, by means of only one photo-detector of four-divisional type, the tracking servo-error signal TES can be obtained by calculating (A+C)-(B+D), and also the focusing servo-error signal FES is obtained by calculating (A+B)-(C+D).
In such servo-error signal generating circuits as represented by the above-mentioned tracking servo-error signal generating circuit 4a and focusing servo-error signal generating circuit 4b, the respective optical powers of the optical beams utilized in write operations, read operations and erase operations for the magneto-optical disk 10 are usually different from each other. Accordingly, the different photo-current, i.e., different detection current, flows in each of the photo-detectors 28, 29 at every write/read/erase operation, in accordance with the the corresponding optical power of the optical beam. Furthermore, the medium reflection factors of the individual tracks on the magneto-optical disk 10 are also different from each other. Therefore, to obtain assuredly the above-mentioned servo-error signals each adjusted to have a constant amplitude, it is necessary for AGC for the servo-error signals to be executed in the servo-error signal generating circuit.
To perform such an AGC assuredly, the following AGC operation must be usually executed for the detection currents detected by the photo-detectors.
First, two kinds of detection currents from each of the photo-detectors are added together, and then a sum signal is obtained.
Second, one kind of the detection current from each of the photo-detectors is subtracted from another kind of the detection current therefrom, and then a difference signal is obtained.
Third, the above-mentioned sum signal is divided by the above-mentioned difference signal.
Consequently, both of the tracking servo-error signal and focusing servo-error signal, each having a constant amplitude, can be always obtained.
FIG. 2 is a circuit diagram showing a servo-error signal generating circuit of the prior art in the case where a photo-detector of two-divisional type is utilized. In this case, either one of the tracking servo-error signal generating circuit and focusing servo-error signal generating circuit will be illustrated representatively.
In FIG. 2, resistors R1, R2 are connected to the respectively corresponding photo-detector units P1, P2 in the photo-detector of two-divisional type. Further, each detection current is converted to the corresponding voltage(detection voltage), and the thus converted voltage is input to each base of two transistors T5, T6. Further, these voltages are added together by an operational amplifier 11, and a level-shift operation for a sum of these voltages is performed by an operational amplifier 13. Further, the sum of the voltages is input to the common base of two transistors T2, T3 in a multiplier circuit of Gilbert type.
In this multiplier circuit, the other two transistors T1, T4 are provided, the respective bases of which bias voltages of direct current type(also referred to as d.c. bias voltages) VR are applied to, and the respective collectors of which are connected to a power supply of the voltage Vcc, via resistors R5, R6. Further, the respective collectors of the transistors T2, T3 are coupled together and directly connected to the power supply of the voltage Vcc as the common collector. An emitter of the transistor T2 is connected to an emitter of the transistor T1 as the common emitter, while an emitter of the transistor T3 is connected to an emitter of the transistor T4 as the common emitter. Further, the respective emitters of drive transistors T5, T6 are connected to the corresponding constant current source 5a, 5b, via resistors R7, R8.
Between a node of the resistor R7 and the constant current source 5a and another node of the resistor R8 and the constant current source 5b, a resistor R9 is connected. This resistor R9 is adapted to convert the differential voltage X-Y as mentioned below to the corresponding differential current which flows through the drive transistors T5, T6.
In this case, when the detection voltages of the two photo-detector units P1, P2, is respectively X, Y, corresponding to the detection levels A, B, the voltage of the collector of the transistor T1 becomes {(X+Y)-X}/(X+Y), i.e., Y/(X+Y). On the other hand, the voltage of the collector of the transistor T4 becomes {(X+Y)-Y}/(X+Y), i.e., X/(X+Y). Therefore, the difference between the respective collectors of the transistors T1, T4 becomes (X-Y)/(X+Y); Namely, the difference signal corresponding to the value of X-Y is divided by the sum signal corresponding to the value of X+Y. Further, if the difference (X-Y)/(X+Y) is input to an operational amplifier 12 to accurately calculate the difference between the respective collectors of the transistors T1, T4, the servo-error signal(TES or FES), in which the AGC operation as described before has been performed, can be finally obtained.
Here, Ic1 and VBE1 are assumed to be the collector current of the transistor T1 and the voltage between the base and the emitter thereof, respectively. Further, Ic2 and VBE2 are assumed to be the collector current of the transistor T2 and the voltage between the base and the emitter thereof, respectively. Further, Ic5 is assumed to be the collector current of the transistor T5. By these assumptions, the following equations are obtained. EQU Ic1=Is.times.{exp(q*VBE1/kT)-1} EQU Ic2=Is.times.{exp(q*VBE2/kT)-1} EQU Ic5=Ic1+Ic2
Where, q denotes an electric charge of an electron, T denotes an absolute temperature, k denotes a Boltzmann constant, and Is denotes a saturation current of a collector in the reverse direction.
Further, in the case where the condition represented by exp(q*VBE1/kT)>>1 and exp(q*VBE1/kT)>>1 is satisfied, the following equation is obtained. EQU Ic1.apprxeq.Ic5/1+exp{q(VBE2-VBE1)/kT}!
Further, the respective currents detected by the photo-detectors P1, P2 are logarithmically converted by the operational amplifier 11, and then supplied to the common base of the transistors T2, T3 as the base voltage thereof. Therefore, the following equation is further obtained. EQU Ic1=Ic5/{1+K*(X+Y)}
Where, K denotes a proportional constant.
Further, in the case where the voltage VR is selected so that the condition represented by K*(X+Y)>>1 can be satisfied, the following equations are simultaneously obtained. EQU Ic1.apprxeq.Ic5/K*(X+Y) EQU Ic4.apprxeq.Ic6/K*(X+Y)
Where, Ic6 denotes the collector current of the transistor T6.
In this case, since Ic5 and Ic6 correspond to the respective output currents of a differential amplifier having the transistors T5, T6, it is apparent from the above-mentioned equations that Ic1-Ic4 is proportional to (X-Y)/(X+Y).
Further, the collector currents Ic5, Ic6 are converted to the corresponding voltages by the resistors R5, R6, respectively. Thereafter, these voltages are input to the operational amplifier 12. Finally, the differential signal taken out from the operational amplifier 12 can be the tracking servo-error signal TES or the focusing servo-error signal FES, which has a constant amplitude independent of the change of the amount of optical beam.
FIG. 3 is a circuit diagram showing a servo-error signal generating circuit of the prior art in the case where a photo-detector of four-divisional type is utilized. In this case, only the focusing servo-error signal generating circuit will be illustrated as the representative of the servo-error signal generating circuits. Hereinafter, any component that is the same as that mentioned before will be referred to using the same reference number.
In FIG. 3, resistors R41, R42, R43 and R44 are connected to the respectively corresponding photo-detector units P41, P42, P43 and P44 in the photo-detector of four-divisional type. Further, the detection currents of the respective photo-detector units P41, P42, P43 and P44 are respectively converted to the detection voltages A4, B4, C4 and D4, corresponding to the detection levels A, B, C and D illustrated in FIG. 1(C).
The two detection voltages A4, B4 are added together by an operational amplifier 14 including the predetermined external resistors r1, r2 and r3. On the other hand, the remaining two detection voltages C4, D4 are also added together by an operational amplifier 15 including the predetermined external resistors r4, r5 and r6. Two kinds of sums A4+B4 and C4+D4 respectively taken out from the amplifiers 15, 16 are input to the corresponding bases of two transistors T5, T6 in a multiplier circuit having the same circuit configuration as in FIG. 2. Further, the four detection voltages A4, B4, C4 and D4 are added together by an operational amplifier 11 including the predetermined external resistors r7, r8, r9, r10 and r11, and a level-shift operation for a sum A4+B4+C4+D4 of all these voltages is performed by an operational amplifier 13 including the predetermined external resistors r12, r13, r14 and r15. Further, the sum A4+B4+C4+D4 is input to the common base of two transistors T2, T3 in the above-mentioned multiplier circuit.
Further, in a similar manner to the case of FIG. 2, the voltage of the collector of the transistor T1 becomes {(A4+B4+C4+D4)-(A4+B4)}/(A4+B4+C4+D4), i.e., (C4+D4)/(A4+B4+C4+D4). On the other hand, the voltage of the collector of the transistor T4 becomes {(A4+B4+C4+D4)-(C4+D4)}/(A4+B4+C4+D4), i.e., (A4+B4)/(A4+B4+C4+D4). Therefore, the difference between the respective collectors of the transistors T1, T4 becomes {(A4+B4)-(C4+D4)}/(A4+B4+C4+D4); Namely, the difference signal corresponding to the value of (A4+B4)-(C4+D4) is divided by the sum signal corresponding to the value of (A4+B4+C4+D4). Further, if the difference {(A4+B4)-(C4+D4)}/(A4+B4+C4+D4) is input to an operational amplifier 12 to accurately calculate the difference between the respective collectors of the transistors T1, T4, the focusing servo-error signal FES, in which the AGC operation as described before has been performed, can be finally obtained.
Further, if other operational amplifiers and another multiplier circuit, respectively having the same configuration as the above-mentioned amplifiers 12, 14 and 15 and the above-mentioned multiplier circuit of Gilbert type, are provided, it becomes also possible for the tracking servo-error signal TES to be obtained.
However, in the positioning control system including the servo-error signal generating circuit according to the prior art as illustrated in FIG. 2 or FIG. 3, the following problems have occurred.
First, such a servo-error signal generating circuit is mainly constituted by an AGC circuit of the voltage-operation type, in which the detection currents in the photo-detectors have to be converted to the voltage utilized as the servo-error signal. Therefore, it becomes necessary for the circuit to have a lot of resistors and a lot of operational amplifiers in converting the detection currents to the useful voltages. Consequently, the circuit per se is likely to have the complicated configuration, and to be easily affected by external noises.
Second, the circuit has a lot of transistors connected in multi-stage configuration. Therefore, it becomes difficult for the levels of all the transistors to be normally distributed, and also it becomes difficult for the operating points of all the transistors to be accurately determined. Consequently, all the transistors can not be driven by a single power supply.
Third, it is difficult for the circuit including such operational amplifiers and the related resistors to be realized by an IC, which can provide the desired circuit with a small size and in relatively low cost for fabrication.

Positioning control system which generates a servo-error signal in accordance with a difference between detection currents

Fujitsu Limited & Texas Instruments Japan


There is disclosed a two-way valve which includes dual valve plates to be sitioned between first and second chambers having varying pressure therein, to relieve excess pressure in either chamber by permitting fluid flow from one chamber to the other. The valve includes a body portion having disposed therein dual valve plates. In the equilibrium state, the first valve plate is spring biased against the valve body in the direction of the first chamber to seal off any flow through the valve. The second valve plate is separately spring biased against the first valve plate in the direction of the second chamber, sealing off flow between the valve plates. When the pressure of the first chamber is greater than the pressure of the second chamber by a predetermined amount, the first and second valve plates move away from the valve body permitting fluid flow from the first chamber to the second chamber. When the pressure of the second chamber exerted on the second valve plate through apertures in the first valve plate is greater than the pressure of the first chamber by a predetermined amount, the second valve plate moves away from the face of the first valve plate permitting fluid flow from the second chamber to the first chamber.

(1) Field of the Invention
The invention relates to relief valves and more particularly to a two-way relief valve, positioned between first and second chambers having varying pressure therein, in order to relieve excess pressure in the first chamber and permit the pressurized medium to exit the first chamber and enter the second chamber, and vice-versa, through a common passageway.
(2) Description of the Prior Art
Pressure relief valves are used to substantially equalize pressure between a chamber and the atmosphere or between two chambers. Typically, the two chambers are adapted to contain dissimilar fluids, such as fuel and air. Such chambers may be disposed in a device for operating in an underwater environment calling for adjacent storage of fluids under pressure. In an underwater environment, the device and chambers may be subject to high underwater pressures as well as high differential pressures. Under such pressures, fluid in one chamber may cause distortion and rupture of the chamber and permit the fluid to enter an adjacent chamber or to escape from the device itself, causing failure of the device. Expected pressure fluctuations within each chamber may also require distinct pressure relief set points for each chamber.
A pair of one way relief valves can function to provide separate relief settings for each chamber, but space available in the device may not permit the use of two valves.
The prior art two-way relief valves are of two types. The first, as illustrated by U.S. Pat. No. 4,773,444, provides one pressure relief set point for the two chambers through a single biasing means common to both chambers. Such valves normally react to total dynamic pressure of the two chambers and are not suited to sensing the differential static pressure between chambers and cannot provide separate pressure relief set points.
The second type, as illustrated by U.S. Pat. No. 4,317,467, consists of a single seat valve utilizing a flexible diaphragm between the two chambers. The diaphragm has a central opening, the edges of which seal against a ball element. Excess pressure on the diaphragm side of the valve forces the diaphragm to flex and move with the ball element in a direction away from the excess pressure until the diaphragm encounters stops. The ball element continues to move, away from the diaphragm, allowing flow through the central opening in the diaphragm. Excess pressure on the ball side of the valve forces the diaphragm to flex in a direction away from the excess pressure. The ball element and diaphragm move together until the ball element encounters a stop. The diaphragm continues to flex away from the ball element allowing flow through the diaphragm opening. While this valve can provide separate pressure relief set points for each chamber and senses differential static pressure, the flexible diaphragm is not suited for use in high pressure applications. The high pressure differentials possible in an underwater environment can cause distortion of the flexible diaphragm leading to leakage between the chambers under normal working conditions. Also the single valve seat arrangement of such devices restricts flow through a single opening in the diaphragm. Under the anticipated high pressures in an underwater environment, such flow restriction can lead to rupture of the diaphragm or of the chamber and device containing the chamber.

Dual valve plate two-way pressure relief valve

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


S,S'-ethylidene dithioacetate is used as a flavoring ingredient for giving the edible products in which it is incorporated not only a sulphurous but also a green, fruity, rich and even meaty quality. It has been particularly successfully used in grapefruit and other fruit flavorings. It can also be used in the preparation of perfuming compostions.

S,S'-ethylidene dithioacetate or 1,1-bis(acetylthio)ethane is a compound of known structure. It was, for example, described by L. Sternson in J. Org. Chem. 1978, 43, 4532, in connection with a study of the behavior of thio acids in basic solutions. We have found no mention of the organoleptic properties of this compound in the prior art, however, nor have we found even a suggestion that it might be useful as a perfuming or flavoring ingredient.
Yet we have now found that this compound has very advantageous flavoring properties and that, in very dilute form, it develops tangs which are very useful for flavoring foods and beverages as well as other products for human consumption which are traditionally flavored.

Use of S,S'-ethylidene dithioacetate as a perfuming and flavoring ingredient


Angular and current distributions for an elliptical birdcage resonator are realized in a design that achieves constant electrical phase between adjacent legs of the coil. Equal peak currents in the driven legs of the orthogonal modes yields exact quadrature operation.

The application of rf excitation to a sample and the pick up of resulting resonant signal is accomplished in a structure surrounding the sample which may be a helical coil, saddle coil, resonant cavity, or a bird cage resonator. The latter structure is the object of the present work, wherein it is desired to couple to a sample which is substantially ellptical in cross section. A bird cage coil is a ladder circuit which closes on itself wherein the current flow around the coil is distributed sinusoidally. As a tuned rf circuit, it is employed in nuclear magnetic resonance apparatus for either or both of the functions of rf excitation and signal detection.
The bird cage coil differs in essential matter from saddle coils, helices and likegeometries by its discrete structure. For the bird cage coil, it is required that the phase shift be discretely distributed around the circumference of the coil from zero to 2.pi. (or 2.pi.k where k is an integer). The phase shift of each element is quite frequency dependent and as a consequence, the bird cage coil is tuned at a discrete frequency to achieve the desired phase shift constraint.
The bird cage coil is particularly well suited to large volume samples as are routinely encountered with apparatus for medical imaging and in vivo analytic spectroscopy. Prior art birdcage coils are discussed by Hayes et al, J. Mag. Res., vol. 63, pp. 622-628 (1985).
The bird cage structure may be regarded as a periodic structure which closes on itself. Periodic elements of the structure produce phase shifts which must aggregate to some multiple of 2.pi. when summed over the closed loop. Geometrically, the resonator has cylindrical symmetry and it is desired that the rf current in the axial direction along the periphery of the structure be proportional to sin k.theta. and/or cos k.theta. where .theta. is the azimuthal angle about the cylindrical axis. The mode k=1 produces the most uniform transverse magnetic fields, such as are commonly used in analytic NMR applications.
The imperfect coupling component between an object studied and the NMR transmitter/receiver limits the performance of the measurement in several ways. First, there is the limitation in the sensitivity of instrumental performance as the weak resonance signals are not coupled in to the receiver in degree sufficient to exceed the inherent noise. There is the limitation on signal to noise ratio which is a consequence of a non-optimum filling factor, e.g., where the object occupies less than the entire sensitive volume. There is also a loss in precision due to the inhomogeneity with which the rf magnetic field is distributed throughout the sensitive volume.
The coupling component takes the form of an inductive structure surrounding the object under study. Typically this may assume the form of a cavity (for extreme frequencies), or more commonly, solenoidal, saddle or birdcage geometry. The birdcage geometry is the subject of the present work wherein it is desired to utilize a birdcage geometry in elliptical cross section to better match the cross section of the human body for medical imaging purposes.
RF coils of elliptic birdcage cross section are known for use in medical imaging of the human head and body. See reported work by Binson, Martin, Griffiths and Edwards, Proc. SMRM, p.272 (1992); Li and Smith, Proc. SMRM, 1342 (1993); Kurczewski, Pavlovich, Stiedly and Rollins, Proc. SMRM, p. 4025 (1992); Li, et al, Proc. ISMRM, p.1411 (1996).
The Binson, et al work taught an arrangement of leg elements such that segments formed by the coil elements and the central axis of the elliptical cylinder (in the cross section thereof) comprise equal areas, the current being distributed among the several legs sinusoidally about the end rings of the coil.
Li and Smith studied the B.sub.1 field obtainable from an elliptical coil having 16 elements (legs) equally spaced in perimeter distance increments on the periphery. For an ellipse of semi-major axis A and semi-minor axis B their approximate formula for the current density on the surface of the ellipse is given as EQU J.sub.c (.theta.)=J.sub.0 cos(.theta.)/(B.sup.2 cos.sup.2 (.theta.)+A.sup.2 sin.sup.2)
to produce a magnetic field substantially parallel to the minor axis.
Kurczewski, et al constructed an elliptic birdcage coil with legs spaced at equal angular increments.
The starting point for the present work is to obtain the continuous surface current distribution K.sub.z (.theta.) on the surface of an elliptical cylinder, which current distribution will produce uniform and orthogonal magnetic fields for quadrature operation in the interior of the ellipsoid. The well known technique of conformal mapping can be employed to transform to the simpler case of cylindrical geometry. Next, a discrete current distribution is obtained, which yields the equivalent field distribution as for the continuous current case. The discrete currents are preferably supported on 4M legs (M, an integer) in order to effectuate quadrature operation. The discrete case is further constrained to the situation of equal peak amplitudes driving the orthogonal modes in order that passive quadrature hybrid combiners may be employed to produce equal power splitting between ports. By reciprocity, the analysis for excitation of the birdcage coil from an rf current source is essentially duplicated for the reception of signals induced on the coil from a sample within the coil. Throughout this work, the sample excitation function for the coil is understood to describe the parallel signal reception function.
In the present work, discrete legs are spaced unequally in the geometric sense on the elliptical perimeter and at equal angular intervals of electrical phase.

Quadrature elliptical birdcage coil for NMR


A multiple fuel tank purge system and method includes providing a pair of fuel tanks, including a main fuel tank for containing impure fuel and a separate, auxiliary fuel tank that contains commercial canned fuel. The engine runs on the impure fuel from the main fuel tank while the engine is in normal use, and then employs a shutdown cycle that switches to the commercial canned fuel from the auxiliary fuel tank for some pre-set time period. This arrangement allows the engine to be purged of the impure fuel (by burning the impure fuel during the shutdown cycle) and replaced by the commercial pre-mixed fuel before the engine is finally shut down. The system may further include a novel fuel cap with a fuel line, a tank within a tank fuel container, and/or an electronically actuated shutdown cycle mechanism.

In recent years, as a result of government mandates, ethanol has become a significant component of gasoline in the United States. Additionally, for various reasons, the quality of gasoline sold across the country has been in decline, which has caused countless problems in combustion engines, including automobile engines, boat motors, lawn mowers and yard equipment, and the like. Further, even if these combustion engines initially run well on gasoline from the pump, various problems surface when the engine is left to sit for extended periods of time. Gasoline having ethanol or other impurities (sometimes including water or sludge and collectively referred to herein as 'impure gasoline' 'impure fuel' or 'impure gas') causes issues with fuel lines, spark plugs, carburetors, and other components, which prevents the engine from running well, or from running at all.
As a result of these problems caused by impure gasoline left in a combustible engine over long periods of non-use, some companies are selling canned gasoline or canned pre-mixed gasoline that contains oil at a specific ratio, such as 50:1 gasoline to oil, or 40:1 gasoline to oil, and contains a fuel stabilizer, but does not contain ethanol or other impurities (referred to herein collectively as 'commercial canned gasoline' or 'commercial canned fuel'). For example, Husqvarna sells commercial pre-mixed gasoline in specific ratios for use with 2-stroke engines that are commonly used in small engines for lawn equipment such as weed trimmers, chainsaws, lawnmowers and the like. This commercial pre-mixed gasoline is significantly more expensive than impure gas from a convenience station pump, but is recommended by many dealers as a preventive measure to guard against the constant repairs and maintenance that results from using impure gasoline in their equipment.
For larger equipment, such as commercial grade lawn mowers, it may be economically infeasible to use the commercial canned gasoline constantly, due to the high cost of that fuel coupled with the high volume of fuel required for such equipment. Therefore, it would be desirable to provide a system that allows a combustion engine to use impure fuel for a particular job, and to purge the impure fuel from the engine, fuel lines and systems prior to shutting the engine down. Such a system would allow the impure fuel to be purged from the engine and replaced with commercial canned gasoline prior to engine shutdown, so that if the engine sits without running for an extended period of time, the engine and its components are not exposed to impure gasoline during that extended period.
The system and method disclosed herein, in one embodiment, utilizes a pair of fuel tanks, each of which provides fuel to the engine. The main fuel tank contains impure fuel, and the auxiliary tank contains commercial canned fuel. Many different engines have been developed to run on multiple fuel sources. Typically, these engines are designed to run on either gasoline or diesel fuel, and may also operate on liquid natural gas, propane, or some other pressurized fuel. The following references show various examples of such multi-fuel engines and systems, and each of these references are hereby incorporated herein, in their entireties:
U.S. Pat. No. 4,305,350 Dual Fuel System
A dual fuel system is disclosed which, when retrofitted to a standard gasoline engine of an automobile, permits the automobile to run on one of two fuels. The dual fuel system comprises two fuel tanks; two carburetors, each connected to a fuel tank and powered by a separate fuel pump; a venturi housing communicating with the carburetors and forming two venturi throats, each throat in registry with an outlet of a carburetor; an adapter forming a single passage therethrough and including an end adapted to be mounted on an intake manifold such that the passage is in registry with an intake opening in the intake manifold; a valve, located in between the venturi housing and the adapter means, for alternately opening and closing a pathway from a preselected venturi throat to the single passage of the adapter so that only one venturi throat communicates with the single passage at a time; a single throttle linkage connected to the throttles of the carburetors such that the throttles of the carburetors operate in unison; a valve linkage which allows remote control of the valve; and a slave linkage extending between the valve linkage and a distributor which is driven by the valve linkage and automatically adjusts the distributor to a predetermined setting by advancing or retarding the timing. The venturi housing may further include an exhaust gas heated helical duct for preheating the air-fuel mixture passing therethrough.
U.S. Pat. No. 4,403,589 Spare Tank System for Motor Vehicle
A spare tank system for a motor vehicle is provided which may conveniently be coupled into the normal fuel line of the vehicle, and which comprises a conduit in which a valve and a fitting are mounted. During normal operation of the motor vehicle, the valve is in a first operating position, and the fuel from the normal fuel system flows through the fuel line and through the conduit to the engine without being impeded in any way. One or more closed cylinders, or other pressurized containers of fuel, such as gasoline, are also provided which may normally be carried in the trunk of the vehicle. Should the vehicle run out of gas, the valve is set to a second operating position, and the nozzle of the container is inserted into the fitting, so that fuel from the container may now flow through the conduit to the engine, with the normal fuel system being shut off.
U.S. Pat. No. 4,437,448 Dual Fuel Supply System
Disclosed herein is a fuel supply system comprising a carburetor including an air/fuel induction passage including a main supply jet and a secondary orifice, a first float bowl having an auxiliary outlet and communicating with the main jet, and a first float controlled valve communicable with a source of a first fuel and operable to control supply of the first fuel to the first float bowl, a combined auxiliary float bowl and primer comprising a housing including a second float bowl, a cavity, a duct extending between the cavity and the second float bowl, a second float controlled valve communicable with a source of a second fuel and operable to control supply of the second fuel to the second float bowl, a movable wall located in the cavity and defining a primer fuel chamber which can be varied in volume and which communicates with the duct, a handle connected to the movable wall for displacing the movable wall to vary the volume of the primer fuel chamber, a check valve in the duct permitting flow from the second float bowl and preventing return flow to the second float bowl, and an outlet communicating with the duct between the primer fuel chamber and the check valve, and a control valve connected to the secondary orifice, to the auxiliary outlet of the first float bowl, and to the outlet of the combined auxiliary float bowl and primer and including a valve member movable between a first position communicating the secondary orifice with the outlet and disconnecting the secondary orifice from the auxiliary outlet and a second position communicating the secondary orifice with the auxiliary outlet and disconnecting the secondary orifice from the outlet.
U.S. Pat. No. 4,462,346 Dual Fuel System for Internal Combustion Engine
Disclosed herein is an internal combustion engine comprising a crankcase, a cylinder extending from the crankcase and having an inlet port, a piston located in the cylinder, a transfer passage located between the crankcase and the cylinder inlet port, a fuel pump adapted to communicate with a source of fuel for normal operation, a carburetor having an air induction passage communicating with the crankcase and including a venturi, which carburetor also includes a float bowl communicating with the fuel pump and a high speed nozzle communicating between the float bowl and the venturi, a low speed fuel nozzle communicating with the transfer passage adjacent the inlet port, and a fuel line communicating between the float bowl and the low speed nozzle and including therein check valve means preventing flow from the transfer passage to the float bowl and permitting flow from the float bowl to the transfer passage, which fuel line also includes fuel flow metering means.
U.S. Pat. No. 4,594,201 Multi-Fuel System for Internal Combustion Engines
A multi-fuel system which will operate the usual factory-manufactured gasoline powered internal combustion engine efficiently on any one of a number of different fuels without modifying or changing the engine. The system involves a non-venturi type of carburetor having a metered inlet and means for controlling the pressure of each fuel delivered to the inlet in accordance with the stoichiometric ratio of that fuel which assures that the proper fuel/air ratio is delivered to the mixing chamber of the carburetor without requiring any change in either the carburetor or engine when a different fuel is used. Additionally, the fuel delivered to the fuel inlet is then directed into the fuel/air mixing chamber without subjecting the fuel to the suction in the intake manifold of the engine.
U.S. Pat. No. 4,640,234 Method of Running an Internal Combustion Engine with Alternative Fuels
A method of operating an internal combustion engine with alternative preheated fuels, or mixtures thereof, at the same compression ratio and supplied with an additional medium for the operation comprises
detecting the flow of air drawn into the engine through the air intake,
proportioning and distributing the fuel to each cylinder in response to at least detected flow,
heating the fuel fed to each cylinder to a temperature between its flame temperature and above its evaporation temperature, but below its auto ignition temperature, and
injecting the heated fuel and the additional medium in a controlled amount into each cylinder through separate feed means at different angles with respect to the wall of the respective cylinder.
U.S. Pat. No. 5,092,305 Apparatus and Method for Providing an Alternative Fuel System for Engines
An alternative fuel system that operates in conjunction with the primary fuel system to utilize the output from the existing or original equipment manufacturer's control module from the primary system, modifies that signal and controls a fuel supply valve for the alternative fuel so that the proper quantity of alternative fuel is supplied to the engine.
U.S. Pat. No. 5,181,488 Two Different Fuel Feeder
A fuel supply system for an outboard motor having a main fuel supply for supplying fuel to the engine and an enrichment fuel supply for supplying a different fuel for starting and cold running. The enrichment fuel supply supplies fuel to the engine through a common enrichment control housing assembly that includes an enrichment pump and an enrichment fuel flow control which are both operated simultaneously. In addition, the enrichment fuel source has a vent system including a vent valve that is operated simultaneously with the enrichment fuel valve and the enrichment pump
U.S. Pat. No. 5,951,050 Integral Reservoir for Tank
The present invention is a system for storing and supplying a maximum amount of fuel from a fuel tank while maintaining a simple structure which is easy to gain access to and repair. The fuel tank structure includes a main fuel tank with an integral internal reservoir tank, a fuel pump, and primary and secondary fuel filters. The reservoir is permanently secured within the fuel tank and provides access, through a removable cover, to the fuel pump allowing efficient and cost effective maintenance to be performed whenever necessary. The system can be manufactured from a wide range of materials and is in compliance with the standards of the industry.
U.S. Pat. No. 6,135,426 Priming System for Internal Combustion Engines
The priming system for a dual feed internal combustion engine provides a lighter, starting fuel to the venturi, the fuel nozzle, or to the carburetor bowl for engine starting. In a first embodiment, the starting or secondary fuel is mixed with the primary fuel in the fuel bowl, and the pure secondary fuel is provided to the fuel nozzle by actuation of a manually-operable primer. In a second embodiment, the secondary fuel is mixed with the primary fuel in the carburetor fuel bowl, and a shot of pure secondary fuel is provided directly to the carburetor venturi by the actuation of a manually-operable primer. In a third embodiment, a primer is manually operated before engine starting to remove primary fuel from the carburetor bowl and return it to the primary fuel tank. Thereafter, pure secondary fuel is provided directly to the carburetor bowl for engine starting through a changeover valve. After the engine has started, the changeover valve is positioned to permit primary fuel to be gravity fed to the carburetor bowl.
U.S. Pat. No. 7,228,841 Fuel Switching for Dual Fuel Engine
An internal combustion engine combusts a first fuel or a second fuel. A method for controlling the engine comprises supplying first fuel to at least one combustion chambers of the internal combustion engine, stopping the supply of the first fuel to the combustion chamber in response to an engine operating condition, and fueling with the second fuel to the at least one combustion chamber after a predetermined period, so as to maintain an engine speed within a predetermined range.
U.S. Pat. No. 7,627,416 Method and Apparatus for Operating a Dual Fuel Internal Combustion Engine
In an internal combustion engine that can burn two fuels, the main fuel may become unavailable, either temporarily or until the main fuel is replenished. The present apparatus determines when to fuel an engine with main fuel and secondary fuel, or secondary fuel alone. The apparatus includes a main-fuel supply system comprising a main-fuel injection valve that introduces main fuel into an engine combustion chamber; a secondary-fuel injection system comprising a secondary-fuel injection valve that introduces secondary fuel directly into the combustion chamber; a pressure sensor associated with the main-fuel supply system for determining injection pressure inside the main-fuel injection valve; and an electronic controller in communication with the pressure sensor and programmable to separately command actuation of the secondary-fuel and the main-fuel injection valve when injection pressure is greater than a predetermined threshold, and to otherwise command actuation of the secondary-fuel injection valve and not the main-fuel injection valve.
U.S. Pat. No. 9,695,764 Multi-Fuel Marine Engine Control System
A marine drive system includes an engine, a fuel system that provides at least two different fuels to the engine, and a fuel selection means for selecting a fuel type. A control unit accesses a set of fuel-specific operating parameters based on the selected fuel type and controls the engine based on the set of fuel-specific operating parameters.
U.S. Application No. 20050072471 Spare Fuel Tank in a Fuel Tank of a Vehicle
A spare fuel tank, installed inside a main fuel tank, having a reasonable volumetric capacity, of small box shape, and having a spare fuel suction pipe there from to the fuel injection pipe. The spare tank of this invention is manufactured at the same time with the main tank, therefore, does not need separate fuel supplying or specific piping connection with the main fuel tank owing to its place. Releasing of the fuel from inside the spare tank is activated by power on the switch connected to a solenoid valve blocking the spare fuel suction pipe.
U.S. Application No. 20080000916 Fuel Supply System for Use in Heavy Construction/Forest Equipment and Secondary Fuel Tanks Thereof
A fuel supply system for supplying a fuel to an engine mounted on an upper frame of heavy construction/forest equipment is provided. The fuel supply system includes a junction tank unit for interflowing a fuel supply line which is connected to a lower end of a primary fuel tank and a fuel supply line which is connected to a lower end of a secondary fuel tank, the fuel supply lines being connected in parallel to each other, a water separator connected to the junction tank unit via a fuel supply line, a fuel supply line for supplying the fuel to an engine from the water separator, and a fuel recovery line for recovering a remaining fuel from the engine to the primary fuel tank.
U.S. Application No. 20090076705 Power Modulated, Dual Fuel, Small Displacement Engine Control System
An engine capitalizes on the advantages of alternative fuels such as ethanol, E-85, and other alcohols, with a small displacement engine, two cylinders or more, and at least a divided fuel tank or alternatively two tanks. An electronic engine control module selects the fuel for operating conditions and delivers the fuel through separate injection systems. The module selects unleaded gasoline for starting, light load and light cruising conditions. Upon greater demands for engine power, the module adds or switches entirely to a secondary fuel such as alcohol, ethanol, E-85 or other ethanol/gasoline blends and reduces or eliminates the introduction of gasoline fuel. The secondary fuel provides more power than unleaded gasoline, thus reducing the engine displacement required for operating a vehicle under a variety of loads. The present invention seeks a substantial engine power increase, reduction in engine detonation, improved cold starting, re-evaluation of turbochargers, a decrease in gasoline consumption, and gasoline as the default fuel. The engine control system allows a small and efficient engine to deliver increased power upon demand over conventional automotive engines. The system modulates boost pressure when using a secondary fuel for operations at an increased power level. The power level increase occurs from the combination of lower stoichiometric, or higher octane, fuel and increased dynamic intake pressures. The system maintains engine power as low, with little or no intake boost pressure, and the gasoline, 85 octane minimum, is delivered through injectors. When higher power is demanded, the system increases boost pressure, at intake, while a secondary power fuel (ethanol, E-85, alcohol and the like), is injected.
However, none of these references addresses the issue of purging impure fuel from an engine before an extended period of non-use.

Multiple fuel tank purge system and method


A method of forming a MOSFET device is provided including: providing an SOI wafer; forming a dummy gate oxide and dummy gates on portions of the SOI layer that serve as channel regions of the device; forming spacers and doped source/drain regions in the SOI layer on opposite sides of the dummy gates; depositing a gap fill dielectric; removing the dummy gates/gate oxide; recessing areas of the SOI layer exposed by removal of the dummy gates forming one or more u-shaped grooves that extend part-way through the SOI layer such that a thickness of the SOI layer remaining in the channel regions is less than a thickness of the SOI layer in the doped source/drain regions under the spacers; and forming u-shaped replacement gate stacks in the u-shaped grooves such that u-shaped channels are formed in fully depleted regions of the SOI layer adjacent to the u-shaped replacement gate stacks.

Short channel effects in bulk metal-oxide semiconductor field-effect transistor (MOSFET) devices occur when the channel length is on the same order of magnitude as the combined depletion widths of the source and drain. Short channel effects can undesirably impact device characteristics, such as shifting the threshold voltage.
In the interest of MOSFET device scaling, smaller channel lengths are needed. With smaller channel lengths, short channel effects however become a greater concern.
Thus, techniques for MOSFET fabrication that permit device scaling while minimizing the impact of short channel effects would be desirable.

Fully-depleted SOI MOSFET with U-shaped channel

International Business Machines Corporation