Coding quantized transform coefficients as occur in image compression includes, for a subset of coefficient amplitude values coding by a first method corresponding to each amplitude of the subset, events of a run of zero or more zero-valued coefficients ending in the single non-zero amplitude, coding by a second method events of a run of zero or more zero-valued coefficients ending in any single non-zero amplitude not in the subset, and coding by a third method the amplitude values of the concatenation of the non-zero amplitude not in the subset. The coding methods produce variable length codewords. The method is suitable for series that have scattered non-zero-valued coefficients.

Two-dimensional variable length coding (2D-VLC) includes collecting or assuming the statistics of two-dimensional block transform coefficient events that are each a run of the most likely-to-occur amplitude, e.g., 0, followed by a coefficient of another amplitude. The coding includes assigning variable length codewords, e.g., optimal codes such as Huffman codes or arithmetic codes, to each event. In the description herein, 0 is assumed to be the most likely-to-occur amplitude. The collecting of or assuming statistics includes tracking the quantized non-zero-valued coefficient amplitudes and the number of zero-valued coefficients preceding the non-zero amplitude, i.e., tracking the runlengths of zeros which precedes any non-zero amplitude along a specified path, e.g., a zigzag scan path for a block of coefficients, e.g., an 8 by 8 or a 16 by 16 coefficient block. FIG. 9A shows Table 1 that illustrates the statistics tabulated as a two dimensional table. In the table, Sij is the likelihood expressed, for example, as a relative number of occurrences of an amplitude of i, i=1, 2, . . . occurring after a run of j 0's, j=0, 1, 2, . . .
A variable length codeword such as an optimal code is then assigned to each of the events that have an Sij above, with the most likely-to-occur element—typically S10 for the case of encoding a block of transform coefficients in transform coding—having the shortest number of bits, and the least occurring event coded using the longest number of bits. FIG. 9B shows as Table 2 an exemplary 2D-VLC table. In the table, Cij is the codeword used to encode the event of the combination of j consecutive 0-valued coefficients followed by a single non-zero coefficient of amplitude i, j=0, 1, . . . and i=1, 2, . . .
2D-VLC is used in common transform coding methods such as JPEG, MPEG1, MPEG2, ITU-T-261, etc., as follows. For motion video, an image is divided into blocks, e.g., 8 by 8 or 16 by 16 blocks. Each image is classified as interframe or intraframe. Interframe images are typically post motion compensation. The blocks of the image are transformed and the transform coefficients are quantized. The quantized transform coefficients are then coded along a specified path according to a 2D-VLC table. Typically, interframe and intraframe images have different 2D-VLC tables. The DC component is typically separately encoded. Furthermore, the 2D-VLC table may be truncated so that the least frequently occurring events use an escape code followed by a fixed length code. A special "EOB" end-of-block code is used to indicate the end of a block when all remaining coefficients are zero.
Still images are similarly encoded, e.g., in the same manner as an intraframe image for motion video.
A table lookup may be used to implement a 2D-VLC scheme. Prior to the table look up, the runlength of zero amplitudes preceding any non-zero amplitude and the non-zero amplitude are determined. The table look up uses a 2D table for those likely events encoded using variable length encoding. An escape code together with a fixed length code is used for relatively less likely-to-occur combinations.
As an example, consider the following ordered sequence of quantized transform coefficients:
4 −3 1 0 −2 1 0 0 1 0 0 0 −1 0 0 . . . 0.
The coded bitstream using the 2DVLC method can be represented by concatenating the following codewords:
C40+S++C30+S−+C10+S++C21+S−+C10+S++C12+S++C13+S−+CEOB.
where + denotes concatenation, S+ and S− represent positive and negative signs, respectively, and CEOB represents the end of block code.
The advantage of 2D-VLC is that both the position of each non-zero-valued coefficient as indicated by the runlength of pre-ceding zero-valued coefficients, and the quantized amplitude value are coded simultaneously as a pair using one 2D-VLC table. This may result in shorter codes on the average, i.e., codes that use fewer bits than using separate VLC tables for the position of each non-zero-valued coefficient and for its amplitude.
Because of the widespread use of image coding, many patents have been issued on different forms of VLC. U.S. Pat. No. 4,698,672 issued Oct. 6, 1987 to Wen-hsiung Chen, one of the inventors of the present invention, for example described one form of a two-dimensional variable length coding method.
Extensions and variations to the common 2D-VLC method are known. For example, the ITU H.263 compression standard defines one such variation sometimes called three-dimensional VLC (3D-VLC). See PCT patent publication WO 9318616 published Sep. 16, 1993 titled PICTURE DATA ENCODING METHOD and also the ITU-T H.263 standard. In 3D-VLC, each symbol ("event") is a triplet (LAST, RUN, LEVEL) that includes: LAST, a binary flag that indicates whether or not the current non-zero amplitude-value is the last non-zero coefficient in the block, RUN, the run-length of zero-value coefficients that precede the current non-zero amplitude, i.e., the number of zeroes since the last non-zero coefficient amplitude, and LEVEL, the current non-zero coefficient amplitude value. Thus, there is no need for a separate EOB codeword; whether or not the non-zero coefficient is the last one is incorporated into the event. A table lookup may be used to implement 3D-VLC.
One deficiency of 2D-VLC is that every non-zero-valued coefficient needs to be accompanied by a runlength code to identify its position, in the form of the number of preceding zero-valued coefficients.
Transform compression methods have been evolving over the years from simple intraframe coding to very sophisticated predictive coding including relatively sophisticated motion compensated interframe and intraframe coding. One result of such improvements is that more and more of the quantized transform coefficients have zero-value, and that non-zero values are more and more scattered along the encoding path. While the 2D-VLC generally performs well for a mixture of clustered and scattered coefficients the advantage of the coding starts to diminish as the quantized coefficients become more scattered. This is due to the fact that the code table for the 2D-VLC will need to become sufficiently large to cover the statistics of the diminishing clustered coefficients and, as a result, the length of the codewords in the 2D-VLC table becomes longer. Using longer codewords to code the sparsely distributed (scattered) coefficients is no longer efficient and desirable.
Thus there is a need in the art for improved methods for encoding a sequence of quantized transform coefficients as encountered in image compression, where non-zero-valued coefficients are scattered, and, in particular, sparse.
In block based transform coding, the inventors have observed that there often is a region, e.g., a low frequency region along the ordering in which non-zero-valued coefficients tend to cluster, i.e., there are often a number of consecutive non-zero-valued coefficients along the low frequency region of the pre-determined path. The Extended 2D-VLC Method of above referenced incorporated by reference U.S. patent application Ser. No. 10/342,537 includes encoding repetitions of some non-zero coefficient values. One variant of the Extended 2D-VLC method provides codewords for all the possible amplitude variations of consecutive coefficients that follow a set of zero-valued coefficients. This effectively reduced the runlength to 1 for all cases. The difficulty of this approach is that there are enormous numbers of patterns that can be generated from the amplitudes of consecutive coefficients. For example, with 32 quantization levels as defined in many common video coding standards, there are in the order of 32n patterns that can be generated from n consecutive coefficients. As such, in a practical implementation, only a limited number of the most likely-to-occur non-zero amplitude values, such as 1 and 2, and a limited number of lengths of consecutive non-zero-values, such as 3 or 4 consecutive values, are regrouped for pattern matching.
Furthermore, in coding, while there may be a region where there are clusters of non-zero-valued coefficients, there is also likely to be a high frequency region where any non-zero-valued coefficients are likely to be scattered.
With these observations in mind, the Basic Hybrid VLC Method of above-mentioned incorporated by reference U.S. patent application Ser. No. 10/869,229 to inventors Chen et al. was developed to encode the position and amplitude of quantized transform coefficients separately and takes advantage of the nature of the distribution of the transform coefficients in the low frequency and high frequency regions.
In one embodiment of the above-mentioned Basic Hybrid VLC Method, two independent types of coding schemes are introduced to code the quantized coefficients along the path. A boundary is established along the path to define two regions, e.g., a low frequency region and a high frequency region. The boundary can be made adaptive to the video depending on a number of factors such as intraframe coding or interframe coding, standard definition television (SDTV) or high definition television (HDTV), complex scene or simple scene, high bit rate coding or low bit rate coding, and so forth. In one embodiment, the encoding of the quantized coefficients in the low-frequency region includes coding the positions of consecutive non-zero-valued coefficients and the positions of consecutive zero-valued coefficients using a run-length coding method of a first type and a run-length coding method of a second type. The encoding further includes coding the amplitude values and sign of the non-zero-valued coefficients. In the high-frequency region, in one embodiment, the encoding of coefficients in the high frequency region includes encoding the positions of either no consecutive zero-valued coefficients or runs of one or more consecutive zero-valued coefficients using a run-length coding method of a third type. The encoding further includes coding the amplitude values and sign of the non-zero-valued coefficients.
In one embodiment of the above-mentioned Extended Hybrid VLC Method, a coding method is used in the second region that takes into account that almost all non-zero-valued coefficients in the high frequency region are ±1. No amplitude coding is needed to encode runs of consecutive zeroes that end in a coefficient of amplitude 1. An exception (escape) code is included to encode those rare non-zero-valued coefficients that have values other than ±1.
The Extended Hybrid VLC Method of incorporated-by-reference U.S. patent application Ser. No. 10/898,654 provides an alternative coding method for the high frequency region by taking advantage of the very few amplitude values in the high frequency region, especially, for example, for low bit rate and interframe applications.
There still, however, is a need to improve improved methods for encoding the second region of the sequence of quantized transform coefficients, where non-zero-valued coefficients are scattered in, in particular, sparse.
Thus, there is a need in the art for improved methods for encoding a sequence of quantized transform coefficients as encountered in image compression in regions where non-zero-valued coefficients are scattered and sparse. This may be applicable to the whole sequence, or in different versions of hybrid coding, to only one, e.g., high frequency region.

Variable length coding for sparse coefficients


A ramp 200 has an attaching portion 221 and an arm holding portion 222. The attaching portion is molded with high polymer material so that the attaching portion has a screw hole 25 for fixing the ramp to the housing of an information recording disk apparatus by a screw. The arm holding portion is molded with high polymer material whose fiction coefficient is small, and the arm holding portion has a storing portion 27 to hold the suspension arm retracted from the recording disk and also has a guide portion 28 against which the suspension arm slides so that it is easily moved in and out of the storing portion 27. The attaching portion 221 and the arm holding portion 222 are united in one by subsequently molding the attaching portion and the arm holding portion.

1. Technical Field
The present invention relates to the structure of a ramp, which retracts a suspension arm, which holds magnetic heads for reading or writing information from or to a recording disk of an information recording disk apparatus being rotated at high speeds, from the recording disk when the disk is not operated and then holds the retracted suspension arm.
2. Description of the Related Art
In information recording apparatuses employed in information processors such as computers or the like, the hard disk apparatus is an information recording disk apparatus employing a magnetic recording disk, which rotates at high speeds, as a recording medium. The hard disk apparatus rotates a plurality of magnetic recording disks (hereinafter stated as xe2x80x9crecording disksxe2x80x9d) at high speeds and reads and writes information by magnetic heads provided to correspond to the upper and lower surfaces of each recording disk.
The magnetic head used in the hard disk apparatus is supported by a suspension arm that is driven by an actuator, and moves over the recording disk at high speeds. Unless the magnetic head crashes, it never touches the recording disk, and the high rotational speed of the recording disk creates a thin cushion of air that floats the magnetic head off the disk by a very small amount.
The magnetic head is required not to contact the recording disk even when the disk does not rotate. This is because there is a possibility that the magnetic head will be fixedly attached on the surface of the recording disk, if the magnetic head contacts the disk for a long period of time when the disk is not rotating. If the magnetic head is fixedly attached on the disk surface, the start of rotation of the recording disk will separate the fixedly attached portion from the disk surface and destroy the disk surface.
The magnetic head is also required not to contact the recording disk even for such a short time that the magnetic head is not fixedly attached on the disk surface. For example, in the case where the magnetic head is contacted with the recording disk not being rotated, there is a possibility that the disk surface will be shaved due to friction which occurs when the magnetic head contacts the disk, during the time that the disk starts rotating and reaches a predetermined rotational speed. Generally, in order to float the magnetic head off the recording disk, the disk is required to have reached the predetermined rotational speed.
As described above, it is necessary that the magnetic head remains retracted from the recording disk until the disk reaches the predetermined rotational speed. For this reason, a magnetic-head holding mechanism called a ramp is recently known. The ramp is used to retract the magnetic head and the suspension arm from the recording disk and hold the retracted magnetic head, when the recording disk is less than the predetermined rotational speed.
The hard disk apparatuses in recent years are provided with a ramp that functions as a saving place for holding the magnetic head retracted from the recording disk during the stop of rotation of the disk and during low rotation. Such a hard disk apparatus unloads the magnetic head to the ramp if the rotational speed of the disk is reduced and becomes less than a rotational speed at which the magnetic head cannot float, and loads the magnetic head over the disk if the rotational speed of the disk rises and reaches an enough rotational speed to float the magnetic head. The method of unloading or loading the magnetic head from or to the ramp, as described above, is called a ramp loading method.
The ramp is molded and manufactured from high polymer material. The ramp is screwed to the housing of the hard disk apparatus and subjected to stress in the direction of compression in which it is pushed against the housing by the tightening torque of the screw. Therefore, if a long period of time passes, creep deformation which is plastic deformation will occur in the ramp formed from high polymer material.
In addition, the information recording disk apparatus has incorporated a motor, a driver circuit or the like to rotate the recording disk at high speeds, so it cannot be avoided that the temperature in the inside of the information recording disk apparatus will rise because of heat generated by the components. Therefore, the surrounding temperatures of the ramp also rise during high rotation of the recording disk and decrease and approach normal temperature during the stop of rotation of the recording disk. That is, the ramp is used under the condition that-temperature changes in a cycle. In that case, as also evident in the field of reliability tests that a temperature cycle accelerates time, for example, creep deformation is liable to occur with the passage of time.
FIG. 7 is a plan view showing a conventional magnetic recording disk apparatus employing the ramp. A magnetic recording disk apparatus 10 illustrated in FIG. 7 houses recording disks 17, a rotary actuator assembly 12, a voice coil motor 16, and a ramp 20 in the inside of a housing 11 and forms an airtight space in the inside. Each of the recording disks 17 has magnetic recording layers on the upper and lower surfaces and are stacked and fixedly attached to a spindle shaft 18. Each disk is rotated integrally with the spindle shaft 18 by a spindle motor (not shown). The upper and lower surfaces of each of the recording disks 17 are used as the information recording surfaces, and a dedicated magnetic head (not shown) is employed with respect to each surface. The actuator assembly 12 has suspension arms 14 stacked by the same number as the information recording surfaces and is supported by a pivot shaft 13. A slider 19 is attached to the front end of each suspension arm 14 and provided with magnetic heads that scan the upper and lower information recording surfaces of each disk. Furthermore, a lifting protrusion 15 is attached to the front end of the suspension arm 14.
The actuator assembly 12 is rotated on the pivot shaft 13 by the voice coil motor 16 so that the slider 19 with the magnetic heads is loaded over the surface of the recording disk 17 or unloaded to the ramp 20. The suspension arms 14 are formed from elastic material and urged in the direction in which each slider 19 attached to each suspension arm 14 approaches the corresponding disk surface of the recording disk 17. If the force to float the slider 19, created by rotation of the recording disk 17, is balanced with the elastic force of the suspension arm 14, the slider 19 will be floated a predetermined distance off the surface of the recording disk 17 being rotated. The ramp 20 is fixed to the housing 11 of the magnetic recording disk apparatus 10 by employing a screw 31, at a position where the front ends of the ramp are near the recording disks 17 and alternately extend into between the disks without contacting any disks.
FIG. 8A is a perspective view showing a conventional ramp where all parts have been molded en bloc by employing high polymer material containing polytetrafluoroethylene (PTFE), and FIG. 8B shows another conventional ramp reinforcing a screw hole with a metal sleeve in the ramp of FIG. 8A. Note that FIGS. 8A and 8B show the ramps of the type that holds suspension arms in the case of stacking three double-sided recording disks.
As illustrated in FIG. 8A, the conventional ramp 20 is configured by an attaching portion 21 and an arm holding portion 22. The attaching portion 21 has a screw hole 25 for fixing the ramp 20 to the housing 11 of the information recording disk apparatus 10 by employing a screw 31. The arm holding portion 22 has storing portions 27 and guide portions 28. Each of the storing portions 27 holds the slider 19 retracted from the corresponding recording disk 17, the slider 19 having the magnetic heads for performing read and write operations on the recording disk 17. Each guide portion 28 makes it easy for the suspension arm 14 to move in and out of the storing portion 27 by sliding the lifting protrusion 15. The attaching portion 21 and the arm holding portion 22 are molded en bloc by a single injection molding operation, with high polymer material containing PTFE. The attaching portion 21 is configured by the screw hole 25 and a bracket 23 surrounding the screw hole 25. The arm holding portion 22 is constructed by the storing portions 27 and guide portions 28, which correspond to the upper and lower surfaces of the recording disks 17, and a support portion 24 which supports the storing portions 27 and guide portions 28 so that they are disposed in the direction in which the recording disks 17 are stacked. The storing portions 27 and the guide portions 28 are provided not only on the upper side of each disk of the recording disks 17 shown in FIG. 8A but also on the lower side and are formed symmetrically with respect to a plane X-Y dividing the disk horizontally into two parts. The circumferential edges of the recording disks 17 are partially inserted into openings 26. That is, each disk edge is interposed between the front edges 29 of the corresponding guide portions 28 without contacting any front edges. The ramp 20 is fixed to the housing 11 by the screw 31 so that the aforementioned positional relationship between the disk edges and the guide portions 28 is satisfied. If the actuator assembly 12 is retracted from the recording disk 17, the lifting protrusion 15 attached to the suspension arm 14 is lifted near the front edge 29 of the guide portion 28, slides against the guide portion 28, and is stored in the storing portion 27. On the other hand, if the actuator assembly 12 moves toward the recording disk 17 in the opposite direction, the lifting protrusion 15 moves out of the storing portion 27, slides against the guide portion 28, and moves over the disk surface from the front edge 29 of the guide portion 28.
In the case where the ramp 20 shown in FIG. 8A is fixed to the housing 11 of the information recording disk apparatus 10 by tightening the screw 31, stress will be accumulated near the screw hole 25 of the attaching portion 21. The stress deforms the peripheral portion with the passage of time and causes errors to occur in the dimension of each part of the ramp 20. That is, creep deformation will occur in the ramp 20 when it is fixed with the screw 31.
The portion where creep deformation becomes a problem particularly in the ramp 20 is the screw hole 25 and front edge 29 of the guide portion 28.
Since the tightening stress of the screw 31 is reduced in the screw hole 25 because of creep deformation, there will arise a problem that the ramp 20 in the information recording disk apparatus 10 loosens. In addition, the front edge 29 of the guide portion 28 needs to be installed so that it does not touch the recording disk and is not too away from the disk, in order to smoothly guide the suspension arm 14 (lifting protrusion 15), positioned over the disk being rotated at high speeds, to the storing portion 27 and, conversely, in order to smoothly guide the suspension arm 14 (lifting protrusion 15), stored in the storing portion 27, to the disk being rotated at high speeds. That is, the front edge 29 of the guide portion 28 needs to be positioned within a predetermined distance perpendicularly away from the recording disk. However, if creep deformation occurs near the screw hole 25 of the attaching portion 21, the front edge 29 of the guide portion 28 will be moved out of a predetermined distance perpendicularly away from the recording disk by the influence of creep deformation. As a result, there will arise a drawback that polymer particles occur, because the ramp 20 is easily contacted with the recording disk by external shock.
To eliminate the aforementioned drawbacks found in the ramp 20, a ramp reinforcing the screw hole 25 with a metal sleeve is known.
Illustrated in FIG. 8B is a ramp 20a reinforcing the screw hole 25 of the ramp 20 shown in FIG. 8A, with a metal sleeve 30.
The ramp 20a is molded with the metal sleeve 30 inserted into the screw hole 25. This can alleviate the stress accumulated near the screw hole 25 when tightening the screw. Therefore, the drawback that the ramp 20a in the information recording disk apparatus 10 loosens can be eliminated. In molding the ramp 20a, however, stress (thermal stress) resulting from a temperature difference during molding is accumulated near the metal sleeve 30 of the ramp 20a, because injection molding is performed under the condition that the metal sleeve 30 at normal temperature is placed in a metal mold managed in a predetermined high-temperature state. Particularly, when the temperature of the metal mold during molding rises to 80 to 90xc2x0 C. near the upper limit of the operating temperature of the hard disk apparatus and then returns to room temperature, the thermal stress causes deformation to occur in the front edge 29 of the guide portion 28, as with the tightening stress of the screw. Furthermore, the metal sleeve 30 in the ramp 20a produces metal powder because it slides against the screw 31, when molding is performed with the metal sleeve 30 inserted in the screw hole 25 and when the ramp 20a is screwed to the housing 11. The occurrence of metal powder must be suppressed to the utmost, since there is a possibility that it will have an adverse effect on the magnetic heads, recording disks 17, etc., of the information recording disk apparatus 10. In addition, the great thermal expansion of resin around the metal sleeve 30 has influence on the guide portions 28. Therefore, applying the metal sleeve 30 to the ramp 20a is effective in order to alleviate the tightening stress of the screw, but is. unsuitable from the standpoint of the occurrence of thermal stress and the occurrence of thermal expansion and metal powder.
Next, as to the fact that the front edge 29 of the guide portion 28 is moved out of a predetermined distance perpendicularly away from the recording disk 17, a further description will be described with the drawings.
FIG. 9 illustrates the section of the ramp 20a and suspension arm 14 of FIG. 8B taken along line Axe2x80x94A of FIG. 7 in the direction of arrow Z. In FIG. 9, the ramp 20a has been fixed to the housing 11 of the information recording disk apparatus 10 by the screw 31. Also, three recording disks 17 (A, B, C) have been partially inserted into the ramp 20a without contacting the ramp 20a, and the suspension arms 14 have been retracted from the recording disks 17 to the guide portions 28. Note that in FIG. 9, there are spaces for a clear understanding of components; however, the lower surface of the bracket 23 and the lower surface of the support portion 24 are in intimate contact with the housing 11 and the ramp 20a is supported by the housing 11.
If the front edge 29 of the guide portion 28 is moved out of a predetermined distance perpendicularly away from the recording disk surface, there are cases where the gap distance (L1up) between the upper surface of the recording disk and the slot of the ramp 20a (opening 26) becomes unequal to the gap distance (L1down) between the lower disk surface and the slot. In the case where either L1up or L1down becomes extremely small, the recording disk is easily contacted with the ramp 20a by external shock during operation of the hard disk apparatus and therefore there is a possibility that reading and writing of information will be disturbed. Since the distances L1up and L1down become unequal, a great difference will occur between the loading and unloading positions over the recording disk which load and unload the sliders (magnetic heads) provided over the upper and lower disk surfaces. The recordable area on the recording disk is determined by the magnetic head in which the distance L2 is longer. That is, if the slider (magnetic head) loading and unloading positions over the recording disk are moved in the radially inner direction of the disk, the recordable area on the disk will diminish, and in the case of the same recording density, there will arise a disadvantage that the entire capacity is reduced. In addition, as an extreme example of the hard disk apparatus, there is a possibility that the data stored on the disk cannot be read out because of movement of the front edge 29 of the guide portion 28.
Notice that FIG. 9 illustrates both the lifting protrusion 15 supported by the guide portion 28 and the lifting protrusion 15 positioned over the disk, for a clear understanding of the present invention.
The drawback that the front edge 29 of the guide portion 28 is moved out of a predetermined distance perpendicularly away from the disk surface is prone to arise when the recording disk 17 is rotating at high speeds, i.e., when the inside of the information recording disk apparatus 10 is in a high-temperature state. This is because it is considered that the direction of deformation is changed by the influence of the aforementioned thermal stress or the tightening stress of the screw, when the front edge 29 of the guide portion 28 in the ramp 20a is deformed due to its thermal expansion during high rotation of the recording disk 17, since high polymer material has a thermal expansion coefficient several times ten to twenty times metal material.
The drawback that the front edge 29 of the guide portion 28 is moved out of a predetermined distance perpendicularly away from the disk surface 17 is more easily liable to occur as the number of the recording disks 17 to be stacked within the information recording disk apparatus 10 becomes greater. This is that the dimension of the ramp 20a becomes greater in the direction in which a plurality of recording disks are stacked, if the number of recording disks increases. For example, in the case where six front edges 29 in FIG. 9 are expressed as A1, A2, B1, B2, C1, and C2 in order from the upper side of the magnetic recording disk apparatus 10 to the lower side contacting the housing 11, the degree that the front edges 29 (A1, A2, B1, B2, C1, and C2) of the guide portions 28 are deformed due to their thermal expansion is increased, because the distance L3 between the front edge 29 (C2) of the guide portion 28 corresponding to the lower surface of the lowermost disk 17(C) and the front edge 29 (A1) of the guide portion 28 corresponding to the upper surface of the uppermost disk 17(A) increases.
FIG. 10 shows the degree that the front edge 29 of the guide portion 28 of the conventional ramp shown in FIGS. 8B and 9 is deformed because of temperature.
In FIG. 10, the degrees of deformation of the six front edges 29 (A1, A2, B1, B2, C1, and C2) in FIG. 9 were measured according to surrounding temperature changes.
As shown in FIG. 10, the degree of deformation of the front edge C1 is on the side of +, while the degree of deformation of the front edge B2 is slightly on the side of xe2x88x92. The front edge C1 in this case is deformed upward and the front edge B2 is deformed slightly downward. Therefore, the gap between the front edge C1 and the front edge B2 narrows with a rise in temperature, and it is understandable that the gap between the front edge B1 and the front edge A2 narrows similarly. Since these gaps diminish, in the worst case the adjacent suspension arms 14 between the front edges C1 and B2 or between the front edges B1 and A2 contact each other during movement and metal particles are produced within the hard disk apparatus. The occurrence of metal particles often destroys the data stored on the disk.
In FIG. 10, the gap between the front edge A1 and the front edge C2 is approximately 85 xcexcm (difference xcex94L due to deformation of distance L3 of FIG. 9) in case of 100xc2x0 C. The value of this gap becomes greater if the number of recording disks 17 to be stacked within the information recording disk apparatus 10 is increased, so it becomes a graver problem.
Accordingly, it is an object of the present invention to provide a ramp in which deformation and loosening because of creep deformation do not occur and metal powder does not occur.
Another object of the invention is to provide a ramp which is capable of reducing the degree of deformation of the front edge of the guide portion caused in the direction in which recording disks are stacked.
In a ramp to store suspension arms which correspond to both sides of multiple double-sided recording disks, still another object of the invention is to provide a ramp where mechanical interference does not occur in adjacent suspension arms even when temperature rises, while reducing the degree of deformation of the front edge of the guide portion due to heat by only resin molding without employing a metal component such as a metal sleeve.
To attain the aforementioned objects, there is provided a ramp, which is used in an information recording disk apparatus having a suspension arm to hold a magnetic head for writing or reading information to or from a recording disk, for retracting the suspension arm from the recording disk and holding the suspension arm. The ramp comprises: a plurality of blocks with a connecting surface, each block being formed from a different high polymer material; and locking means in undercut form formed in each of the connecting surfaces. The blocks are connected mechanically and united in one by the locking means.
In the ramp for an information recording disk apparatus according to the present invention, the ramp is constructed by (1)an attaching portion molded with high polymer material, which is slight in creep deformation and small in thermal expansion coefficient, so that it is provided with a screw hole for fixing the ramp to a housing of the information recording disk apparatus by a screw and (2) an arm holding portion molded with high polymer material whose fiction coefficient is small, the arm holding portion having a storing portion to hold the suspension arm retracted from the recording disk and also having a guide portion against which the suspension arm slides so that it is easily moved in and out of the storing portion. The attaching portion and the arm holding portion are united in one by the locking means in undercut form.
In the ramp for an information recording disk apparatus according to the present invention, creep deformation occurs less in the high polymer material that is employed in the attaching portion than in the high polymer material that is employed in the arm holding portion. In addition, the thermal expansion coefficient of the high polymer material which is employed in the attaching portion is smaller than that of the high polymer material which is employed in the arm holding portion.
In the ramp for an information recording disk apparatus according to the present invention, the high polymer material that is employed in the attaching portion is selected from among polyetherimide (PEI), polyimide (PI), polycarbonate (PC), polyethersulphone (PES), polyphenylenesulfide (PPS), and high polymer material mixed with glass fibers or carbon fibers. In the ramp for an information recording disk apparatus according to the present invention, the high polymer material with a small friction coefficient, which is employed in the arm holding portion, is liquid crystal polymer (LCP) or contains polytetrafluoroethylene (PTFE).
In the ramp for an information recording disk apparatus according to the present invention, the high polymer material which is employed in the attaching portion and the high polymer material which is employed in the arm holding portion have the same temperature range in a temperature condition required of a metal mold for molding both materials.
In accordance with the present invention, there is provided a method of manufacturing a ramp that retracts a suspension arm, which holds a magnetic head for writing or reading information to or from a recording disk, from the recording disk and holds the suspension arm. The method comprises the steps of: designing the ramp so that it is constructed by a plurality of blocks; molding the blocks subsequently with different high polymer materials; molding an undercut in a connecting surface of the first molded block which contacts the second molded block; and causing the undercut to function as part of a metal mold in molding the second molded block. According to this manufacturing method, the blocks that are molded with different high polymer materials are united in one.
In the ramp for an information recording disk apparatus according to the present invention, the temperature of the metal mold is higher than 90xc2x0 C. which is higher than the highest temperature that a hard disk apparatus reaches when it is installed or in use. At temperatures less than this, the distortion or stress, stored in the inside of the ramp, is difficult to release. Therefore, ramps molded at temperatures less than 90xc2x0 C. can be easily discriminated, because ramp deformation is conspicuous if the ramps are raised to 90xc2x0 C.
In the ramp manufacturing method according to the present invention, the metal mold for molding a plurality of blocks molds one block at a first molding position, then rotates along with the molded block to a second molding position and molds another block. According to the present invention, there is provided an information recording disk apparatus comprising: a rotary actuator assembly having a suspension arm connected thereto; a plurality of magnetic disks stacked; a ramp, disposed near the magnetic disks, for retracting the suspension arm; and a housing to house the actuator assembly, the magnetic disks, and the ramp. The ramp as set forth in any one of claims 1 to 12 is fixed on the housing by an attaching screw.

Ramp for information recording disk apparatus

International Business Machines Corporation


A linear measuring instrument having a pair of measuring tips mounted on respective jaws moveable relative to one another along an elongated beam particularly adapted for measuring inside dimensions has a digital display unit responsive to display increments of movement of one jaw relative to the beam on which the jaw is slidingly mounted. The pair of measuring tips are spaced from one another, when the jaws are in engagement with one another, a selected calibration distance. The end user of the instrument follows a sequence of steps, including resetting the display unit to read zero and then adjusting and fixing the position of the other jaw to the beam until the selected calibration distance registers on the display unit.

This invention relates to a measuring caliper instrument and more particularly, to such instruments used for measuring inside diameters and the like, such as the internal diameter of cylindrical brake drums.
Periodically it is necessary to check the wear of vehicle brake drums to determine if the drums are within a prescribed tolerance range. This tolerance range, set by the manufacturer, insures that the brake drums are still within a certain internal diameter and secondly, the degree of roundness. If a brake drum's internal diameter does not fall within the prescribed ranges, then the drum may be machined or replaced.
U.S. Pat. No. 4,782,595 shows a device used to measure the internal diameters of brake drums comprising a two-part bracket with a portion of one part slidingly received within the other part and with a dial gauge having a rotating member adapted to rotate as the parts are moved relative to one another. Pins are mounted at opposite ends of the device and are placed within a brake drum with the two-part bracket spread apart until both the pins contact the drum wall with the gauge indicating the distance between the pointers through a rack and pinion arrangement.
The device is calibrated by inserting the pins between two end tabs of a calibration bar so that a pointer of a course scale on the bracket and the dial gauge pointer indicate the known length of the calibration bar.
In order to take a measurement with the device one must add the two numbers thereby increasing the time needed to take a reading than would be required with a single scale as well as increasing the possibility of making an incorrect reading.
Linear measuring devices useful for both outside diameters as well as inside diameters are known in the art having digital display units which facilitate quick and accurate taking of measurements as shown, for example in U.S. Pat. Nos. 4,229,883 and 4,972,603. Both of these devices incorporate an elongated beam member on which is disposed circuit means which cooperate with a caliper member mounting a battery powered digital display unit which has pick-up and counting means responsive to the circuit means on the beam so that the amount of movement on the caliper member is successively digitally displayed. The digital display units are provided with re-setting means so that the display counter can be calibrated by being made zero at a selected position, for example, when inside dimension measuring bill 3 of Pat. No. 4,229,883 passes moveable bill 17 when their measuring surfaces come into alignment or as shown in FIG. 7 of Pat. No. 4,972,603 when measuring jaws 88, 81 pass one another so that their measuring surfaces come into alignment.
However the provision of measuring arms which are configured and mounted in such a manner as to pass one another and still provide accurate, reliable movement, is expensive and relatively complex.
It is an object of the invention to provide an improved linear measuring instrument having digital display means particularly suitable for measuring inside dimensions such as internal diameters.
Another object is the provision of such an instrument which is relatively inexpensive and yet is reliable and is easily used in a consistent manner from one user to another.
Yet another object is the provision of a method for calibrating to a selected standard dimension a measuring instrument particularly suited for measuring inside diameters.
Briefly, in accordance with the invention, calipers adapted for measuring internal diameters and the like having a digital display unit are provided with first and second jaw members slideably mounted on an elongated beam. Each jaw member has an arm mounting a measuring tip extending in a first direction with the arms both lying in the same plane. The first jaw member comprises a frame formed with a beam receiving recess and a groove in communication with the recess. A stop surface is disposed in the groove which interacts with a stop pin mounted on the beam adjacent an end thereof and moveably received within the groove. Set screws are mounted in the frame to selectively fix the frame to the beam and an adjustment screw moveable in the direction of the longitudinal axis of the beam extends from the side of the frame closest to the second jaw member toward the second jaw means. The second jaw member comprises a housing mounting the digital display unit which is provided with a needle receiving resetting aperture.
According to a feature of the invention, one side of the frame is placed flush with one side of the beam and the frame is then fixed to the beam by the set screws. With the two jaw members in engagement with one another, the adjustment screw is rotated until the distance between the measuring tips equals a selected calibration distance at which point the adjustment screw is fixed in place. The caliper instrument is then in condition to provide to an end user.
According to a feature of the invention, an end user calibrates the display unit by loosening the set screws and, with the two jaw members held in engagement with one another, moving the beam to the right as seen in FIG. 4 until the stop pin engages the stop surface. A calibration needle is then inserted into the resetting aperture of the display unit to cause the display to show zeros. The beam is then moved in the opposite direction, i.e. to the left as seen in FIG. 4, until the selected calibration distance is displayed and the set screws are retightened to fix the position of the frame to the beam. The instrument will then remain in its calibrated condition until battery replacement or in the event that the original factory calibration is changed.

Measuring caliper instrument having a digital display and method for calibrating same


In a refrigerating machine, a water cooling device having a cooling tower or an ice heat storage tank is provided as a heat exchanger for cooling refrigerant after heat-exchange in a heat-source side heat exchanger between an outdoor expansion valve and the heat-source side heat exchanger.

1. Field of the Invention
The present invention relates to a heat exchange apparatus having an outdoor unit and a plurality of indoor units in which cooling operation or heating operation can be simultaneously performed in the plural indoor units or both cooling operation and heating operation can be simultaneously performed in a mixing mode in the plural indoor units, and a refrigerating machine having the heat exchange apparatus.
2. Description of the Related Art
There is generally known a refrigerating machine (heat exchange apparatus) in which an outdoor unit and a plurality of indoor units are connected to one another through an inter-unit pipe comprising a high pressure gas pipe, a low pressure gas pipe and a liquid pipe and cooling operation or heating operation can be performed in a plurality of indoor units at the same time, or both cooling operation and heating operation can be performed in a mixing mode in a plurality of indoor units at the same time (see Japanese Patent No. 2804527).
This type of refrigerating machine has a problem that when cooling operation is carried out, the refrigerant temperature at the exit of a heat-source side heat exchanger is increased in connection with increase of the outside air temperature and thus the cooling performance is lowered. Furthermore, it has also a problem that when heating operation is carried out, the refrigerant temperature at the exit of the heat-source side heat exchanger is reduced in connection with decrease of the outside air temperature and thus the heating performance is lowered.

Heat exchange apparatus and refrigerating machine


A mobile communication system in which overlapping location areas are defined by radio base stations on an autonomous distribution basis. In a first embodiment, a mobile station registers the location thereof when moved in a radio zone which is not included in a location area notified by a radio base station and held therein. In a second embodiment, the mobile station registers the location when entered a radio zone in which location area being notified by the radio base station does not include the radio zone where the mobile station registered the location last. In a first and a second embodiment, the mobile station memorizes radio zones which it has passed after location registration as route information and may report the route information to a radio base station in the event of next location registration. The radio base station sequentially includes in the location area the radio zones which frequently appear in the route information. In a third embodiment, in response to a terminating call meant for the mobile station, a mobile switching center sends a calling signal meant for the mobile station to all of the radio base stations. In response, each radio base station effects calling if the own location area where it is situated is coincident with a location area included in the calling signal. In a fourth to a sixth embodiment, each radio base station measures the traffic of registration signals or that of calling signals so as to increase or decrease the number of radio zones included in the own location area in matching relation to the measured traffic.

1. Field of the Invention
The present invention relates to a location registration and paging procedure for mobile stations included in a mobile communication system and, more particularly, to a location registration and paging procedure for mobile stations each being movable in a plurality of radio zones in a mobile communication system which has overlapping location areas.
2. Description of the Prior Art
A conventional car telephone, portable telephone or similar mobile communication system is implemented with a miniature zone scheme in which the entire service area belonging to the system is covered by a plurality of radio zones. The term "radio zone" refers to a range in which each radio base station is communicable with a mobile station mounted on a car, for example, over a radio channel. A single radio base station is situated in each radio zone, and a plurality of mobile stations each is freely movable in the radio zones.
In a mobile communication system of the type using miniature zones as mentioned above, each mobile station has to register the location thereof to inform a radio base station of the current radio zone in which it exists. To avoid an increase in the traffic of exclusive control signals for location registration, it has been customary to divide the entire service area into sets of radio zones which neighbor each other to thereby define a plurality of location areas. A mobile station registers the location every time it is handed over from one location area to another. When a terminating call meant for a certain mobile station arrives, radio base stations situated in the location area where the mobile station has registered the location call the mobile station by broadcasting. Each location area is provided with an adequate size in consideration of the fact that including an excessively great number of radio zones therein would increase the calling traffic and thereby reduce the efficiency.
The way to divide the entire service area into a plurality of location registration areas may generally be classified into two kinds, i.e., one for non-overlapping location registration areas in which a radio zone belongs to a fixed location registration area and the other for overlapping location areas in which a radio zone belongs to a plurality of location registration areas.
Regarding the number, the non-overlapping location areas each has a relation of 1: n (natural number) to the radio zones belonging thereto, i.e., a radio zone is prevented from belonging to a plurality of location areas at the same time. In a mobile communication system, it sometimes occurs that a mobile station positioned in the vicinity of the border between nearby location areas moves across the border repetitively. In such a case, the non-overlapping location areas would result in the increase in the frequency of location registration of the mobile station and thereby cause the control signal traffic for location registration to center on radio base stations situated in the vicinity of the border.
The overlapping location areas eliminate the above problem. Specifically, if the duplication of radio zones in a first and a second location area is admitted, a mobile station does not have to register the location repetitively so long as it moves in the radio zones belonging to both of the first and second location areas. This is successful in preventing the control signal traffic from centering on particular radio base stations. To set up an overlapping location area, a set of a plurality of radio zones neighboring the lastest radio zone where a mobile station has registered the location may be defined as a second location area.
A specific method of setting up overlapping location areas was reported at THE INSTITUTE OF ELECTRONICS, INFORMATION AND COMMUNICATION ENGINEERS, JAPAN, 1989 SPRING NATIONAL CONVENTION, Paper No. B-863. This method sets up a location area on a radio zone basis by using two-dimensional positional coordinates particular to each radio base station.
Specifically, the above-mentioned method is such that when a mobile station has registered the location in a radio base station belonging to a given radio zone, it memorizes positional coordinates being notified by the radio base station. Every time the mobile station is handed over from one radio zone to another, it receives positional coordinates being notified by the radio base station situated in the new radio zone. When the mobile station enters a radio zone whose radio base station is situated at a predetermined distance R from the radio base station in which the mobile station has registered the location previously, it registers the location again.
However, the location area based on the coordinates of the radio base station in which a mobile station has registered the location has fixed topography with no regard to the position of the mobile station. This brings about a problem that even when a mobile station moves only one-dimensionally such as on a straight thruway, a location area including radio zones which the mobile station will not pass is set up.

Location registration and paging procedure for mobile communication


A method of retaining and dispensing a detergent tablet in an automatic washing machine. The method includes the step of providing a dispensing device having a flexible and resilient cage structure which is liquid permeable. Another step is flexibly deforming the cage structure and inserting the detergent tablet in the cage structure such that said detergent tablet is retained therein. Yet another step is placing the dispensing device including the detergent tablet into an automatic washing machine for a washing cycle in which a wash liquor is caused to pass through the cage structure to progressively dissolve and dispense detergent from the detergent tablet.

Detergent compositions formed as non particulate solids such as bars or tablets or briquettes are known in the art. In the following, the term "tablet" will refer to any form of non particulate solids. The tablet provides a number of advantages to both the consumer and the manufacturer. For example, the tablet avoids spillage of the detergent composition. Furthermore, the tablet eliminates the need for the user to estimate the dosage of detergent composition required and ensures that the correct dosage of detergent composition per wash cycle is used by the user.
To further simplify handling and in order to maximize dissolution, thus improving the performance of the detergent tablet, many detergent composition manufacturers provide the consumer with dispensing devices in which to place the detergent tablet prior to being placed in the washing machine. Indeed, dispensing devices in the form of baskets or cradles are often utilized for example in automatic dish washing machines to maximize the performance of the tablet.
An example of a dispensing device for tablets which may be introduced in an automatic dish washing machine is described in co-pending European Patent Application No. 95304115.9. This dipensing device may comprise a fastening means which fastens the dispensing device to the interior of an automatic washing machine such that it can be released therefrom when required. In an automatic dish washing machine the dispensing device is usually attached to the exterior of the cutlery basket or the crockery basket.
Since the detergent composition is already dosed and compacted into tablets, smaller packages can be used for the packaging of the tabletted detergent. Smaller packages mean less space needed for storage and transportation, therefore also logistic and cost improvements of the packaged detergent are achieved. However, part of the logistic and cost improvements may be lost when the dispensing device is included in the packages. Indeed, the volume occupied by the dispensing device has to be further added to the package containing the detergent tablets. Thus, part of the advantage of reducing the space for a package resulting of detergents compacted into tablets is lost when a dispensing device is included in the packages.
Furthermore, the cage-like dispensing device of the co-pending European Patent Application No. 95304115.9 requires quite sophisticated molding techniques. Such a sophisticated molding technique is for example split cavity molding. The use of such sophisticated molding techniques results in high mould costs and correspondingly high cost per piece.
It is therefore an object of the present invention to provide a method for retaining a detergent tablet and dispensing the detergent tablet in a wash liquor in which a dispensing device is supplied occupying less amount of volume in a package and can be produced with a cost efficient process.


A method of evaluating a gravity-type flow conveyance system is disclosed. The method includes the steps of identifying, quantifying and totaling all upstream inflow sources to compute an anticipated flow at a plurality of access points in the system. The actual depth of flow at each access point is then measured and converted to a theoretical flow for each access point. The anticipated flow and the theoretical flow are then compared to determine whether any restrictions on flow might exist in the system and also to prioritize further inspection and repair of the system.

To prevent water pollution and further the goals of the Clean Water Act, regulations and enforcement actions have historically focused on the output of wastewater treatment facilities. However, in recent years, the technology for treating wastewater has largely matured to the point that treatment facilities are decreasingly the source of significant water pollution. To further eliminate potential water pollution, the United States Environmental Protection Agency, municipalities and sanitary sewer system authorities have recently refocused their attention and resources on the network of pipes that transports wastewater to the treatment facility.
These piping networks may be constructed as a combined wastewater and storm water system, or dedicated exclusively to the transport of wastewater. In either case, untreated wastewater can overflow from the system into the environment. For the health of the community and environment, and to remain in compliance with the law, a sanitary sewer system authority must prevent such overflows. To retain a permit to operate a sanitary sewer system, an authority must "take all reasonable steps to minimize or prevent any discharge . . . which has a reasonable likelihood of adversely affecting human health or the environment." 40 CFR 122.41(d).
Sanitary system overflows, or SSO's, can be caused by a number of factors. The primary cause of overflows is restrictions and blockages in the sewer system, most often caused by the accumulation of debris, roots and/or grease in a sewer pipe. Although less common, underground pipes also may settle, rupture or deteriorate, especially in older collection systems. In wet weather conditions, storm water runoff may infiltrate a dedicated sanitary sewer system, or overwhelm the capacity of a combined sanitary sewer and storm water system, and cause the sanitary system to overflow. Because an SSO may result in untreated sewage being released into the environment or backing up into residential basements, municipalities and sanitary sewer system authorities seek technology and methods to identify actual and potential causes for an SSO.
In the past, municipalities and sanitary system authorities have addressed actual and potential sanitary sewer system overflows in a number of ways. Many authorities have simply built additional or redundant capacity into their piping system to prevent overflows. Studies have shown, however, that restrictions and blockages are the primary cause of overflows, not lack of capacity in the system. Thus, simply adding additional capacity leads to piping systems that are underutilized and more expensive than necessary to serve the sanitary needs of the community.
Some larger authorities have employed complex and expensive evaluation methods to identify potential causes of SSO's. These methods often include the use of expensive devices for monitoring flow at different points in the system and the employment of personnel and/or consultants to collect and analyze data from the flow monitoring devices. The data is often analyzed with proprietary software by paid consultants.
These techniques, associated devices and software, however, are often beyond the financial capacity and skill set of small and medium sized sanitary system authorities. Also, because of the cost and complexity of these evaluation methods, a complete review of the entire sanitary system is typically not performed. Thus, although general problem areas in the system may be identified, specific pipe restrictions and blockages may be missed.
In addition, due to the cost of employing data collection personnel and consultants, the review and analysis of most sanitary sewer systems is typically short lived, and usually only performed in response to a specific problem or overflow. Prior art evaluation techniques are typically project-based, specific to a particular problem and not designed for ongoing assessment of the collection network. The resultant data is typically not incorporated into the ongoing operation and maintenance procedures of the authority, and is therefore not helpful in identifying and solving future problems in the system.
In addition, because the evaluation of sanitary sewer systems has historically been project-based and in response to a specific problem or overflow, little attention has been paid to the ongoing maintenance and upkeep of the system. However, sewer system assets that are not regularly maintained will deteriorate faster, leading to higher replacement and emergency response costs. When a sewer system is regularly maintained, its lifetime can be increased and maintenance costs distributed over the lifetime of the system. Thus, a regular evaluation and maintenance program will save money in the long run, avoid unexpected and unplanned for costs and safeguard against the health risks associated with SSO's.
Accordingly, an object of the present invention is to provide an evaluation method for identifying potential causes of sanitary system overflows including restrictions and blockages in the piping system, ruptured or deteriorated pipes and sources of storm water inflow and infiltration into the system.
A further object of the present invention is to provide an evaluation method that specifically identifies problem points in the collection network and avoids the need for building additional or redundant capacity in the system.
Yet another object of the present invention is to provide an evaluation method that is inexpensive to administer and easy to understand.
An additional object of the present invention is to provide an evaluation method that can be used to evaluate the entire sanitary sewer system and that can be easily performed on an ongoing basis.
Finally, an object of the present invention is to provide an evaluation method that can be incorporated as part of an ongoing sewer system maintenance and upkeep program to prolong the life of the system and avoid unexpected and unplanned for costs.

Process for the assessment of gravity-type collection networks


An LCD panel module includes a common boosting converter, an LCD boosting circuit, an LDO control circuit, and constant current circuits for parallel-connected LED elements and series-connected LED elements. The LCD panel module is so configured that a type-switching unit can switch over between Type 1 in which the LED elements are connected in parallel and Type 2 in which the LED elements are connected in series. The common boosting converter preliminarily boosts a battery voltage supplied from a lithium ion battery to a low voltage or a high voltage and supplies the boosted voltage to the parallel-connected LED elements or series-connected LED elements respectively. The LCD boosting circuit boosts the low voltage and supplies it to an LCD panel, while the LDO control circuit steps down the high voltage and supplies it to the LCD panel.

1. Field of the Invention
The present invention relates to a power supply apparatus which supplies device drive voltage by boosting power supply voltage.
2. Description of the Related Art
To drive an LCD (liquid crystal display) panel for battery-driven portable equipment, such as cellular phones or PDAs (personal digital assistants), it is necessary to supply a drive voltage, which is a battery voltage of about 3.6V supplied from a lithium ion battery or the like boosted to a high voltage of about 15 V. In battery-driven portable equipment, LED (light-emitting diode) elements are used for a variety of purposes, which include use as a backlight for an LCD (liquid crystal display), as a flash for an attached CCD (charge coupled device) camera or as an illumination with the LED elements flashing in different emission colors. Driving the LED element requires a large current of about 20-100 mA but a low drive voltage of about 4.5 V. Thus, the LCD panel and the LED element require a very different level of the drive voltage.
Since the drive voltage for the LCD panel is considerably higher than the battery voltage, the battery voltage must be boosted in multiple steps by a charge pump circuit or the like. For instance, a power supply circuit for an LCD is disclosed in Reference (1), which receives an input of power supply voltage from a logic unit in a driver IC for driving an LCD panel and boosts the input voltage in multiple steps by a charge pump circuit that uses a large number of capacitors, and thereby generates a high voltage for driving the LCD panel.
Related Art List
    (1) Japanese Patent Application Laid-Open No. 2001-125062.
To boost the battery voltage by a charge pump circuit, a large number of capacitors are necessary according to the number of boosting steps, and therefore it becomes a big problem on component mounting especially when there arises a need to develop portable equipment smaller and thin-shaped. In addition, if boosting circuits are individually provided for the LCD panel and the LED element, which require different drive voltages, for boosting the battery voltage to the respective drive voltages, a mounting area in a power supply IC expands, and therefore it becomes an obstacle in miniaturizing and lightening the portable equipment.


Ligand reagents are disclosed which consist essentially of recombinant hyperglycosylated cytokines, expressed in yeast, which are purified and conjugated to various functional moieties, for example, biotin groups, via oligosaccharide residues. Methods of using such ligand reagents are also disclosed.

The present invention relates generally to molecular biology, and particularly to a new class of conjugate ligands based on hyperglycosylated cytokines.
Cytokines are soluble proteins which mediate the hormonal regulation of various cells and tissues. Cytokines deliver a signal to target cells by binding to integral membrane proteins or complexes of proteins, known as receptors. Cytokine receptors contain an extracellular ligand binding region and an intracellular region activated by cytokine binding, which delivers a signal to other intracellular components of the cell. The interaction of cytokines with the extracellular regions of cytokine receptors is highly specific.
Lymphokines are cytokines which regulate and coordinate the activites of various cell types in the immune system. Different immune cells express different populations of lymphokine receptors. For example, T cells, which are involved in the cellular immune response, express varying numbers of interleukin-2 (IL-2) receptors on their cell membranes, depending upon their state of activation. By enumerating the number of cells expressing IL-2 receptors in a particular plasma sample and the average number of receptors per cell, a sensitive assessment can be made of the extent of T-cell activation. Other classes of immune cells express other receptors, for example, receptors for IL-4, IL-3 and IL-1. If the appropriate technology were available, analysis of cytokine receptor expression could be employed as a sensitive tool to enumerate, image or isolate cells in various cell populations or tissue samples. This detection technology could form the basis for new avenues of diagnosis and therapy. For example, certain leukemias are characterized by expression of GM-CSF receptors on the leukemic cells. Such leukemias could be diagnosed and typed by flow cytometry if a reagent capable of detecting GM-CSF receptors were available.
Currently, counting and typing of immune and other circulating blood cells can be conducted by flow cytometry, for example, fluorescence-based cell sorting, wherein laser activation of fluorescent labeling dyes is employed to distinguish cells for separation in an electrostatic field. Flow cytometric apparatus and techniques are well developed, and have been reviewed by Parks and Herzenberg, Meth. Enzymol. 108:197 (1984) and Cambier and Monroe, Meth. Enzymol. 103:227 (1983). Cells may be labeled for flow cytometry using specific antibody for particular membrane proteins or receptors. In direct immunofluorescence studies, specific antibody is directly conjugated to a fluorescent dye moiety, for example, fluorescein isothiocyanate. In indirect immunofluorescence methods, an unlabeled specific antibody is detected using a labeled antibody which binds the Fc region of the unlabeled antibody.
The use of flow cytometric techniques to detect cytokine receptors is limited by the lack of specific antibodies for most receptors, which is due to the lack of purified receptor (or cell lines expressing high levels of receptor) for immunization. With a few exceptions, e.g., IL-2 receptor (p55 or Tac antigen), preparations of cytokine receptors sufficient to raise specific antibody are not available, due to the low abundance of many receptors on known cell types. For these reasons, biochemical studies of polypeptide hormone receptors have often been limited to indirect methods such as .sup.125 I-ligand crosslinking, due to the combined problems of low receptor abundance and the lack of specific antibody or other molecular probes.
An alternative approach to cytokine receptor detection by flow cytometry using antireceptor antibodies involves labeling the cytokine itself for use as a fluorescence reagent. For example, Shirakawa et al., J. Immunol. 138:4243 (1987) disclose labeling of human IL-1.alpha.with fluorescein isothiocyanate (FITC) to study the expression of IL-1 receptors on human peripheral T cells. Yamasaki et al., Science 241:825 (1988) describe flow cytometric analysis of cells based upon IL-6 receptor expression, using recombinant IL-6 conjugated to biotin, which was then labeled using FITC-avidin. This technique can also be used to purify receptors, based upon the high affinity (Kd 10.sup.-15 M) binding of biotinylated polypeptides to avidin and streptavidin for receptor affinity chromatography. One difficulty with this approach is the need to produce a biotinylated ligand which retains the ability to bind to its specific cell surface receptor. The most common approach has been to couple the N-hydroxysuccinimide ester of biotin to primary amines on the protein backbone, e.g., as disclosed by Yamasaki et al. However, if primary amino groups are critical to the receptor-binding function of the ligand, this approach is not feasible. One alternative approach to protein biotinylation involves conjugation to oligosaccharide moieties, which has been demonstrated with immunoglobulins. However, recombinant proteins produced in the most common bacterial expression systems (e.g., E. coli) lack glycosylation, and recombinant proteins produced in other systems are glycosylated only to a small extent or to an unpredictably heterogeneous extent.
Another problem in receptor detection by fluorescence-based flow cytometry is low levels of receptor expression. In order to discriminate cells on the basis of receptor expression where receptors are sparsely expressed, for example, at levels of 15-100 receptors per cell, it is necessary to employ a detection reagent which can be labeled with a sufficient number of dye moieties to permit detection of receptor-bearing cells above background levels of fluorescence. To detect receptors which are expressed at levels of 500-1000 receptors per cell requires a reagent with multiple dye residues per ligand. Conventional methods of cytokine labeling, for example, direct FITC-conjugation and FITC-avidin-biotin conjugation, are incapable of providing cytokine reagents with a sufficient number of fluorescein residues to detect many classes of receptors, for example, human GM-CSF and IL-3 receptors. To address these problems, new types of cytokine reagents are needed.
The present invention provides an improved class of cytokine reagents for use in flow cytometry and other receptor-based cell separation techniques in which functional groups, for example, biotin groups, are conjugated to oligosaccharide moieties. The improvement of the present invention resides in the use of recombinant hyperglycosylated cytokines, which are produced in yeast. Yeast are capable of expressing protein having higher levels of O-linked and N-linked mannose (glycosylation) than mammalian cells. The resulting "halo" of polysaccharide on the hyperglycosylated cytokine, which can account for as much as 70% of the weight of the molecule, provides a useful substrate for conjugation of multiple biotin or other linker moieties. Hyperglycosylated cytokines can be labeled to very high specific fluorescence levels without deleteriously affecting the receptor binding characteristics of the conjugate ligand. Hyperglycosylated cytokine conjugates can be employed not only in fluorescence-activated flow cytometry, but also in other analysis, imaging or separation techniques.


This invention provides a process for producing a free hydroxylamine aqueous solution, by letting an alkali react with separated sulfates, for conversion into ammonia and sulfates not containing any nitrogen atom, recovering the valuable ammonia and recycling it in the reaction system for effective use.

The present invention relates to a process for producing a free hydroxylamine aqueous solution, in more detail, a process for producing a free hydroxylamine aqueous solution, in which free hydroxylamine is obtained by the reaction between hydroxylammonium sulfate and ammonia, comprising the steps of mixing a lower alcohol to precipitate and separate the sulfates containing ammonium sulfate produced by the reaction; mixing an alkali with the separated ammonium sulfate, to produce ammonia, and recovering and recycling the produced ammonia.
Hydroxylamine is industrially widely used as a medical and agricultural intermediate raw material or as a metal surface treating agent, etc.
However, since free hydroxylamine is very unstable and is easily decomposed, it is generally converted into a relatively stable hydroxylamine salt (hydroxylammonium salt) for use. The decomposition of free hydroxylamine is especially likely to occur, for example, in the presence of heavy metal ions, at a high concentration, in a strong alkali or at a relatively high temperature.
When hydroxylamine is actually used in the above applications, free hydroxylamine, not a hydroxylammonium salt, is preferably used, and an aqueous solution containing free hydroxylamine at a higher concentration is often required. Such a free hydroxylamine aqueous solution has been obtained by several methods.
As a recent method for obtaining free hydroxylamine, the reaction between a hydroxylammonium salt and an alkali is used. For example, in the case of the reaction between hydroxylammonium sulfate and ammonia, after completion of reaction, the reaction system contains a large amount of ammonium sulfate in addition to the intended free hydroxylamine. So, it is proposed to separate free hydroxylamine from ammonium sulfate, for obtaining a highly pure and highly concentrated free hydroxylamine solution.
In the method described in U.S. Pat. No. 4,956,168, the ammonium sulfate precipitated in the reaction between hydroxylammonium sulfate and ammonia in an alcohol is removed, to obtain a free hydroxylamine alcohol solution. The alcohol solution is then mixed with an acid other than sulfuric acid, to synthesize a hydroxylammonium salt other than hydroxylammonium sulfate.
Furthermore, German Patent Publication No. 1247282 and German Patent Publication No. 3601803 (Japanese Patent Laid-Open (Kokai) No. Sho62-171905, U.S. Pat. No. 4,778,669) describe methods for obtaining a free hydroxylamine alcohol solution by letting hydroxylammonium and ammonia react with each other in an alcohol and removing the precipitated ammonium sulfate.
Furthermore, in German Patent Publication No. 19547758 (U.S. Pat. No. 5,837,107), hydroxylammonium sulfate and an alkali are caused to react with each other in water not containing any alcohol, and the precipitated salt is removed. Then, the reaction solution is supplied into an intermediate stage of a column, and separated into a hydroxylamine aqueous solution not containing any salt discharged from an upper stage and an aqueous solution containing a salt discharged from a lower stage.
In the conventional methods for obtaining free hydroxylamine by the reaction between hydroxylammonium sulfate and ammonia, it is mainly intended to separate the free hydroxylamine and ammonium sulfate produced by the reaction, but what will happen with the separated ammonium sulfate is not discussed.
Especially if the hydroxylammonium sulfate used for the reaction is obtained according to the Raschig""s method, recently a purchased sodium nitrite aqueous solution is often used as a raw material, instead of ammonium nitrite. In this case, the sulfates obtained after completion of reaction contain not only ammonium sulfate but also the sodium sulfate contained in the raw material. When the sulfates are a mixture of them, it is very difficult to separate ammonium sulfate from sodium sulfate, and it is not appropriate to use the mixture as a valuable substance. If the sulfates are dissolved to be dumped as waste water, an environmental problem arises since ammonium sulfate contains nitrogen atoms.
As described above, if hydroxylammonium sulfate is treated by ammonia, a large amount of sulfates containing ammonium sulfate are produced. Hitherto, the sulfates are separated and removed beforehand, to simplify the subsequent operation of obtaining free hydroxylamine. When the ammonium sulfate in the separated sulfates is dumped as waste water, any treatment for environmental conservation is necessary since the waste water contains nitrogen atoms.
An object of the present invention is to provide a process for producing a free hydroxylamine aqueous solution, in which the sulfates separated like this are caused to react with an alkali, to be converted into ammonia and sulfates not containing any nitrogen atom, for recovering valuable ammonia from them, to recycle it in the reaction system for effective use.
Another object of the present invention is to provide a process for producing a free hydroxylamine aqueous solution, which can be effectively used when the sulfates obtained after completion of reaction are a mixture consisting of ammonium sulfate and sodium sulfate difficult to separate.
Other objects of this invention will be clarified in the following description.
This invention which achieves the above objects is a process for producing a free hydroxylamine aqueous solution, in which a free hydroxylamine aqueous solution is obtained by letting an aqueous solution or slurry containing hydroxylammonium sulfate and a gas mainly containing ammonia react with each other, mixing a solution mainly containing a lower alcohol with the produced aqueous solution or slurry, and separating the precipitated sulfates containing ammonium sulfate, comprising the steps of mixing an alkali with the separated sulfates, to produce ammonia gas containing water, and recycling the ammonia in the reaction system.
This invention also includes the following effective modes.
(a) As the aqueous solution or slurry containing hydroxylammonium sulfate, some or all of the hydroxylammonium sulfate containing sodium sulfate obtained according to the Raschig""s method is used.
(b) The alkali is sodium hydroxide or calcium oxide and/or calcium hydroxide.
(c) As sodium hydroxide, a sodium hydroxide aqueous solution is used.
(d) As the calcium oxide and/or calcium hydroxide, a calcium hydroxide slurry is used.
(e) The sulfates containing ammonium sulfate are formed into an aqueous solution, and an alkali is mixed with it.
(f) A solution mainly containing a lower alcohol is mixed with the reaction solution remaining after separating and removing the sulfates containing ammonium sulfate precipitated in the ammonia reaction.
(g) The sulfates obtained by separation and an alkali are mixed, to produce ammonia which is recovered and recycled in the reaction system.
(h) Powdery hydroxylammonium sulfate is added to the reaction solution remaining after separating and removing the sulfates containing ammonium sulfate precipitated in the ammonia reaction, and ammonia is again caused to react.
(i) The operation of the above (h) is repeated plural times.
(j) The reaction solution obtained in any of the above (f) to (i) and a solution mainly containing a lower alcohol are mixed.
(k) The lower alcohol is methanol.
(l) The reaction between hydroxylamine sulfate and ammonia is effected in the presence of a hydroxylamine stabilizer.
(m) The mixing of the sulfates and the alkali is effected at room temperature or higher temperature.
(n) Nitrogen gas or air is blown into the mixed solution consisting of the sulfates and the alkali, and the ammonia produced by the reaction is obtained by degasification.

Process for producing free hydroxylamine aqueous solution

Abstract: This invention is a process for producing a free hydroxylamine aqueous solution, in which a free hydroxylamine aqueous solution is obtained by letting an aqueous solution or slurry containing hydroxylammonium sulfate and a gas mainly containing ammonia react with each other, mixing a solution mainly containing a lower alcohol with the produced aqueous solution or slurry, and separating the precipitated sulfates containing ammonium sulfate, comprising the steps of mixing an alkali with the separated sulfates, to produce ammonia gas, and recycling the ammonia in the reaction system.


An improved process for synthesizing acrylic polymers, which is highly controllable to achieve high molecular weight, high conversion rate, and low polydispersity involves continuously introducing initiator(s), acrylic monomer(s), and optionally other monomers capable of polymerizing with the acrylic monomer(s), into a microchannel of a microreactor having an integral micromixer and an integral heat exchanger.

Hydrogen-bonding group containing materials capable of associating into polymer networks have attracted significant research attention and have been proposed as candidate materials for fiber coating applications due to their good solubility, coating properties and elasticity (Nair, K, P; Victor Breedveld, V.; Weck, M. Macromolecules 2008, 41, 3429-3438). Free radical polymerization of acrylic monomers initiated by AIBN serves as an excellent method for synthesis of such materials (Islamova, R. M., et al., Polymer Science 2006, 48(3); 130; Islamova, R. M., et al. Russian Journal of Applied Chemistry 2006). Radical polymerization is a fast and exothermic reaction which can quickly release large amounts of heat. Processing at a very large scale has to be slowed down due to the limited heat removal capacity of a batch reactor. A new device featuring miniaturization of the polymerization unit and greater heat transfer efficiency with no heat accumulation during polymerization is required. The microreactor technology is considered an attractive solution because microreactor has process miniaturization and micro heat exchanger (Watts, P.; Wiles, C. Chem. Commun., 2007, 443). Recently, polymerizations using microreactor technology have been investigated (Vandenbergh, J.; Junkers, T., Polymer Chemistry 2012, 3(10), 2739). However, up to now, such polymerization processes have been performed using tubular reactors without integral mixing. In 2005, the Yoshida group reported the preparation of poly(butyl acrylate) in a microreactor system which consisted of a T-shaped micromixer and tubular flow paths with a heat-conductive reactor (Iwasaki, T.; Yoshida, J., Macromolecules 2005, 38, 1159). It was found that material with a lower polydispersity index (PDI) of molecular weight than that produced in a batch reactor could be prepared. In this device, the microtube possessed good properties for heat exchange, but didn't play a role in mixing.
Polymerization of butyl acrylate and acrylamide was used as a model reaction to study polymerization in a microreactor. Our results demonstrated that a microfluidic process strategy with simultaneous micromixing and heat transfer for the scale-up of a free radical co-polymerization process is a promising method.

Synthesis of an acrylate polymer in flow reactor


A resistive random access memory (RRAM), a controlling method for the RRAM, and a manufacturing method therefor are provided. The RRAM includes a first electrode layer; a resistance switching layer disposed on the first electrode layer; a diffusion metal layer disposed on the resistance switching layer; and a second electrode layer disposed on the diffusion metal layer, wherein at least one extension electrode is disposed in the resistance switching layer.

Memories are generally classified into volatile memories and non-volatile memories, and RRAM is one of the non-volatile memories which can be driven by electric current or voltage and can switch between the high impedance state and the low impedance state so as to store data. In the structure of RRAM, it is composed of a stacked layer of metal-insulator-metal, and the insulator may have reversible switching characteristics. During operations, a pulse voltage is applied to the RRAM to switch its resistance states to perform "data writing" or "data erasing", and then a small bias is used for capturing current values to determine the impedance state in order to read data.
FIG. 1 is a conventional RRAM 6, which includes two electrode layers 61 spaced apart with each other and made of platinum (Pt) and titanium nitride (TiN), respectively, and a resistance switching layer 62 interposed between the two electrode layers 61 and made of nitroxide silicon oxynitrid (SiON). Then, an endurance experiment is performed on the conventional RRAM 6. That is, an alternate current is applied to the RRAM 6, such that the resistances of the RRAM 6 are continuously switched, and current values in the experiment are recorded and plotted during each switching as shown in FIG. 2. The formation or breaking of a conduction path is occurred in the resistance switching layer 62 during the switching between the high impedance state and the low impedance state; however, because each formation of the conduction path is not fixed, an irregular resistance transition may be occurred. That is, as shown in FIG. 2, the deviations of the solid dots are more obvious, which affects the stability of the RRAM 6.

Resistive random access memory, controlling method and manufacturing method therefor

INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE


A chip package assembly and a method for manufacturing the same are provided. A die is attached to one of pins located around a chip carrier, so that an electronic component such as a diode is packaged in the chip package assembly and is electrically connected in series with other dies inside the package, thereby improving the degree of integration of the chip package assembly, and reducing a volume of the external circuit.

A lead frame that is applied in the conventional Quad Flat No-lead (QFN) package, as shown in FIG. 1, includes a chip carrier 11 located at the center of the lead frame and multiple pins 12 surrounding the chip carrier 11. In the QFN package, multiple dies are generally packaged to improve the integration of the chip package assembly. However, packaged dies are stacked or distributed on the chip carrier which is located at the center of the lead frame. As shown in FIG. 2, a die 21 and a die 22 are stacked on the chip carrier 11. An electrode of the die 22 is electrically connected with the die 21 via a wire 221. Electrodes of the die 21 are connected with a pin 12 via wires 211. Alternatively, as shown in FIG. 3, the die 21 and the die 22 are distributed on the chip carrier 11, and electrodes of the die 21 and electrodes of the die 22 are connected with the pins 12 via the wires 211 and the wires 221 respectively.
In some application, however, an input terminal or an output terminal of a die is required to be connected in series with another die such as a diode, for driving an external circuit or protecting a terminal of an integrated circuit (IC). In such case, a control chip or a metal-oxide-semiconductor (MOS) field-effect transistor cannot be integrated with a diode into one package by using the QFN package shown in FIGS. 2 and 3. Instead, a separate diode is connected in series with an external circuit of a packaged die.

Chip package assembly and method for manufacturing the same

SILERGY SEMICONDUCTOR TECHNOLOGY (HANGZHOU) LTD


A coaxial opto-electronic device used for SFF (Small Form Factor) and SFP (Small Form-Factor pluggable) opto-electronic transceiver module comprises an opto-electronic TO CAN (201) having a cap border (106) at one end, a metal tube (203) disposed around the opto-electronic TO CAN (201), and an isolation ring (202) interposed between the end face of the metal tube (203) and the cap border (106). The coaxial opto-electronic device allows the device's metal case ground to be insulated from the inner data ground, and at the same time, the device outer form is small enough and the size of inner part thereof is enlarged.

1. Field of the Invention
This invention relates to a coaxial opto-electronic device. In particular, the present invention relates to a package structure. For example, the present invention may find particular use in opto-electronic device used in SFF (Small Form Factor) and SFP (Small Form Factor pluggable) opto-electronic transceiver module which is used to interface a host device with an optical communications network.
2. Description of the Related Art
Fiber optics is increasingly used for transmitting voice and data signals. The use of light as a transmission medium presents a number of implementation challenges. In particular, the data carried by light signal must be converted to an electrical format when received by a device. Conversely, when data is transmitted to optical network, it must be converted from an electronic signal to a light signal. A number of protocols such as ANSI Fiber Channel protocol are typically implemented to define the conversion of electronic signals to optical signals and transmission of those optical.
Typically, a transceiver module is electrically interfaced with a host device, such as a host computer, switching hub, network router, switch box, computer I/O and the like via a compatible connection port. Moreover, in some application it is desirable to miniaturize the physical size of the transceiver module to increase the port density and therefore accommodate a higher number of network connections within a given physical space. In addition, in many applications, it is desirable for the module to be inserted and removed from the host system without removing electrical power. To accomplish many of these objectives, international and industry standards have been adopted to define the physical size and shape of optical transceiver modules to ensure compatibility between the optical transceiver modules from different manufacturers. For example, in 1998, a group of optical manufacturers developed a set of standards for optical transceiver modules called the Small Form-Factor Pluggable ("SFP") Transceiver Multi-Source Agreement ("MSA"). This standard defines the details of the electrical interface, the physical size and shape for the SFP transceiver modules and the corresponding host port, so as to ensure interoperability between different manufacturers' products.
While such standards may recommend a limited physical size, the inner opto-electronic devices also demonstrate a smaller physical size. At the same time, the standards require the chassis grounds and external electromagnetic interference shields should not be attached to circuit ground. With the trend of the metallized SFP case, the demand of the case ground of the device in SFP case insulated from the circuit ground has arisen. If the case of the device is insulated from the signal ground, it doesn't matter whether the SFP case is metal or not.
For coaxial devices applied to SFP, the problem to assure as large as possible inner space with insulating structure package has emerged.

Coaxial opto-electronic device having small form factor insulating structure

Wuhan Telecommunications Devices Co., Ltd.


A pivoting bracket for supporting a boat seat at an appropriate position above the deck of a boat, such bracket permitting the seat normally to remain upright, but also to be pivoted, on occasion, into a low center of gravity position adjacent the deck, thus to provide better visibility to the person operating the boat. This bracket comprises a pair of interfitting members, with one of these members being a clevis-shaped first member having spaced-apart portions, and the second member being interposed between the spaced-apart portions. A pivot pin extends through the spaced-apart portions of the first member as well as through the second member, the pivot pin permitting the members to reside in an aligned relationship when the seat is intended to reside in an upright position. The pivot pin also permits the members to reside in an angular attitude when the seat is to be moved out of the upright position. An appropriately placed locking device enables the members to be locked in an aligned relationship, such that a user may sit on the seat without the seat possibly moving into an unusable position. The locking device is preferably a spring biased locking pin that can be moved into any one of a number of possible locking positions, so that the seat may be held in a desired relationship to the deck.

It is well known that fishing boats approximately 17 feet long are often fitted with a rather tall seat, located forward of the location where the boat is steered. Such a seat is usually supported by a relatively long pedestal whose lower end fits into a hole or fitting of suitable size located in the deck of the fishing boat.
The seat typically rests comparatively high above the deck, so in the interests of providing the fisherman with a clear view of the waterway ahead, the seat and its pedestal is ordinarily placed in a substantially flat position on the deck while the boat is underway, but is then placed in the operational, usable position when the fishing grounds are reached. The fisherman almost always finds the seat comfortable as well as advantageous to utilize while fishing, particularly when a long wait may ensue between catches.
When moving from one fishing spot to another, however, there is a temptation to travel with this forwardly-located seat in the upstanding, deployed position, without going to the trouble to remove it from its deck fitting, and laying it flat on the deck. Unfortunately, if the seat is left in the deployed position, it may well jump out of its deck fitting if the wake of another boat is encountered, with the consequence that the seat (and pedestal) will fly rearwardly and strike the driver of the boat, or cause other damage.
It was in a n effort to overcome the danger of a dislodged seat causing damage to a fishing boat or to the occupants thereof that the present invention was evolved.

Fold down seat utilizing pivotally constructed bracket


A novel compound 4H-indeno[4,5-D]-1,3-dioxole, 3A,5,6,7,8,8B-hexahydro-2,2,6,6,7,8,8-heptamethyl is dislosed as well as the use of the compound as a fragrance chemical. The fragrance compound is suitable for use in creating fragrances, and scents in items such as perfumes, colognes and personal care products.

There is an ongoing need in the fragrance industry to provide new chemicals to give perfumers and other persons ability to create new fragrances for perfumes, colognes and personal care products.
U.S. Pat. No. 4,902,840, hereby incorporated by reference, discloses the use of substituted tetrahydroindane derivatives as useful fragrance chemicals. U.S. Pat. No. 6,303,798 hereby incorporated by reference, discloses the use of 4,4a,5,6,7,8,9,9b-octahydro-7,7,8,9,9-pentamethyl-indano[4,5-d]-dioxin as a fragrance chemical.
Despite this disclosure and numerous other patents on fragrance materials, there is a continuing need to provide additional fragrance materials such that perfumers may create new fragrances for various applications.

This patent is subject to a terminal disclaimer.