A strut aligning fixture capable of improving misregistration of struts arranged between two glass plates for a vacuum glass envelope to hold the glass plates spaced from each other at a predetermined interval. An alignment plate is formed of a first alignment plate member of a small thickness and a second alignment plate member of a large thickness by lamination. The first alignment plate member is provided with strut holes, which can be formed with high accuracy because of a reduced thickness of the first alignment plate member. The alignment plate is used as a fixture for arranging the struts in the vacuum glass envelope while minimizing misregistration of the struts.

1. Field of the Invention
This invention relates to a vacuum glass envelope formed of at least two glass substrates and more particularly to an envelope suitable for use for a display device.
2. Discussion of the Background
An envelope for a display device in which an electron emission source and illuminants or luminous elements such as phosphors or the like is generally constructed in the form of a vacuum glass envelope. Conventionally, the vacuum glass envelope is formed of a first glass substrate and a second glass substrate arranged in a manner to be opposite to the first glass substrate and provided therein with illuminants or luminous elements providing a display plane and an electron source for exciting the illuminants for luminescence. The first and second glass substrates are arranged so as to be spaced from each other at a predetermined interval by means of struts interposedly arranged therebetween.
Such construction of the conventional envelope is as shown in FIG. 7, wherein struts 101 are interposedly arranged between a first substrate 102 and a second substrate 103. The struts 101 each are formed into a diameter of about 50 .mu.m and a length of about 200 .mu.m.
Now, an arrangement of the struts 101 between the first substrate 102 and the second substrate 103 will be described hereinafter with reference to FIGS. 6(a) to 6(c).
First, a glass fiber which is, for example, about 50 .mu.m in diameter which is a material for each of the struts 101 is cut into a length of, for example, about 200 .mu.m.
The struts 101 thus cut each are then washed and subject to positioning on the first substrate 102 by means of a fixture 110.
The fixture 110, as shown in FIG. 6(a), is formed into a box-like shape and includes an alignment plate 111 provided with strut holes 114 for receiving the cut struts 101 therein while raising them, a porous section 112 made of a porous material and arranged under the alignment plate 111, and an evacuation section 113 through which the fixture 110 is evacuated.
The strut holes 114 are formed on the alignment plate 111 in a manner to positionally correspond to arrangement of the struts 101 on the first substrate 102.
In the fixture 110 thus constructed, the evacuation section 113 is connected to a pump (not shown) to cause the interior of the fixture 110 to be evacuated therethrough, during which the cut struts 101 are spread on the alignment plate 111 of the fixture 110. This causes gas sucked though the strut holes 114 to be passed through the porous section 112 and evacuated from the evacuation section 113, so that the cut struts 110 each are caused to enter, by suction, the strut hole 114 formed into a diameter somewhat larger than that of the strut 101 while being raised, resulting in being arranged in the strut hole 114 while being kept raised, as shown in FIG. 6(a).
Then, as shown in FIG. 6(b), a glass substrate 120 to which a transfer paste 121 is applied is placed on the fixture 110 while keeping the paste 121 facing the fixture and then contacted with the struts 101 held in the fixture 110, so that the transfer paste 121 may be transferred to an upper or one end surface of each of the struts 101.
Subsequently, as shown in FIG. 6(c), the first substrate 102 is placed on the fixture 110 in which the struts 101 having the transfer paste 121 thus transferred thereto are held while being aligned with the fixture 110, so that the struts 101 are attached at the one end surface thereof to the first substrate 102. Then, the first substrate 102 is subject to calcination at a predetermined temperature to melt the transfer paste 121, to thereby fix the one end surface of each of the struts 101 to the first substrate 102 by welding.
The transfer paste 121 mainly consists of a sealing glass of a low softening point which has lead oxide incorporated therein so as to permit a thermal expansion coefficient of the transfer paste 121 approach to that of the first substrate 102 made of glass and may optionally contain a solvent and the like, resulting in exhibiting stickiness.
Thereafter, the second substrate 103 is arranged in a manner to be opposite to the first substrate 102 to which the struts 101 are fixed in a manner to be spaced from each other at predetermined intervals, resulting in a glass envelope being provided. Then, the glass envelope is evacuated to vacuum, so that a vacuum glass envelope in which the struts 101 are firmly held between the first substrate 102 and the second substrate 103 by an atmospheric pressure is provided as shown in FIG. 7.
Alternatively, the vacuum glass envelope may be prepared in a different way. More particularly, the transfer paste 121 is transferred to the other end surface of the struts 101 and the first and second substrates 102 and 103 are laid on each other while being aligned with each other. Then, the substrates 102 and 103 are placed in an oven, resulting in being sealedly joined to each other. Concurrently, this causes the transfer paste 121 to be melted, to thereby fix the other end surface of the struts 101 to the second substrate 103, so that the glass envelope may be provided in which the struts 101 are arranged between the substrates 102 and 103.
In order to ensure that the first substrate 102 and second substrate 103 are arranged in a manner so as to be opposite to each other at a predetermined interval, side plates of a predetermined height, glass beads, glass fibers or the like are interposed therebetween while being positioned at a periphery thereof. Then, the above-described sealing operation is carried out for providing the glass envelope.
The struts 101 are arranged in the glass envelope in a manner to be spaced from each other at intervals of about 2 to 5 mm.
Arrangement of the struts 101 in the strut holes of the alignment plate 111 which is carried out as described above is shown in FIGS. 8(a) and 8(b). As will be noted from FIG. 8(a) and particularly FIG. 8(b), it is often seen that the struts 101 are each arranged in the strut hole while being inclined or positionally deviated with respect to the strut hole.
One of the reasons is that when the strut hole into which the strut 101 is inserted is formed into a diameter of about 53 .mu.m in order to permit a slight gap which is sufficient to prevent the strut 101 from being caught in the hole to be provided between the strut hole and the strut, the strut 101 and strut hole are caused to have tolerances as large as +3 .mu.m and +5 to 0 .mu.m, respectively.
Another reason is that preparation of the alignment plate 11 with increased accuracy fails to form it into a thickness of about 70 .mu.m or more, to thereby cause the struts 101 to be projected from the alignment plate 111 by a distance as large as about 130 .mu.m.
Thus, the struts 101 are each caused to be positionally deviated or misregistered with respect to the strut hole by a magnitude up to about 20 .mu.m. When the vacuum glass envelope is used for a display device in which a picture cell pitch and a picture cell interval are respectively defined to be 360 .mu.m and 80 .mu.m, such misregistration in an amount as large as about 20 .mu.m causes the strut 101 to interrupt display operation of a display section or leads to short circuit of electric wirings in the display device.
The reason why the conventional vacuum glass envelope fails to form the alignment plate 111 into a thickness of about 70 .mu.m or more is due to the way in which the alignment plate is prepared.
Now, preparation of the alignment plate 111 will be described hereinafter with reference to FIGS. 9(a) to 9(d), as well as FIGS. 10(a) and 10(b).
First, a photoresist 132 is applied to a stainless steel plate 131 as shown in FIG. 9(a) and then a glass dry plate 133 having a mask 134 wholly formed thereon is placed on the photoresist 132, followed by irradiation of light to the glass dry plate 133, to thereby subject the photoresist 132 to exposure, as shown in FIG. 9(b). Then, the photoresist 132 is developed, resulting in only portions 135 of the photoresist exposed to light being left on the stainless steel plate 131, as shown in FIG. 9(c).
Such photoresist portions 135 thus left are formed in large numbers on the stainless steel plate 131 and positions of the photoresist portions 135 left on the plate 131 are determined to be positions at which the struts 101 are to be arranged while being raised.
Then, the stainless steel plate 131 is subject to electroplating while using Ni as a plating material, so that a Ni plate 136 is formed on only the stainless plate 131 as shown in FIG. 9(d).
Thereafter, the photoresist 135 is removed from the stainless steel plate 131, resulting in the Ni plate 136 which is formed with a strut hole 137 being formed on the stainless steel 131, as shown in FIG. 10(b). Then, the Ni plate 136 is peeled off from the stainless steel plate 131, so that the alignment 111 is provided which is formed with a plurality of such strut holes 137 as shown in FIG. 10(b).
The thickness of the alignment plate 111 may be increased by increasing a thickness of the photoresist 132 applied to the stainless plate 131. Unfortunately, such an increase in thickness of the photoresist 132 substantially prevents light irradiated for exposure from reaching the depths of the photoresist 132, leading to a failure to fully expose it to light. Also, the light irradiated is diffracted at a boundary between the mask 134 and the photoresist 132 and scattered in the photoresist 132, therefore, an increase in thickness of the alignment plate 111 causes light to be gradually diffused as it penetrates through the photoresist 132. This causes the photoresist 135 subjected to exposure as shown in FIG. 9(b) to have a configuration like a trapezoid-like shape, so that a variation in dimension of the strut hole 137 formed is increased with an increase in thickness of the alignment plate 111, as shown in FIG. 11.
Such an increase in variation of dimension of the strut hole or formation of the strut hole into a trapezoid-like shape undesired further promotes misregistration of the strut 101 from a center of the strut hole to a degree sufficient to cause the vacuum glass envelope to be unsuitable for use for a display device.
Thus, it will be noted that the prior art fails to increase a thickness of the alignment plate 111 to about 70 .mu.m or more while ensuring formation of the strut holes with satisfactory accuracy.


A query is received that includes two or more facets of a multidimensional inverted index for a collection of documents. Each document is associated with at least one facet. Generation of the multidimensional inverted index includes creating one or more entries. Each entry includes a combination of two or more facets and a posting list of indications for the documents associated with respective facets of each entry. Each indication identifies a document. Generation of the index also includes determining documents associated with respective facets of the combination of each entry. The multidimensional inverted index is searched for an entry having the combination of two or more facets included in the query and a search result is returned. An indication for a document may be included in a posting list if it is determined that the document is associated with each facet of the combination of facets of the entry.

A search engine may be used to locate particular documents in a collection of documents. In addition, a search engine may be used to locate particular keywords or phrases in a document. Search engines may use one or more indices to locate particular documents, keywords, or phrases. In addition, search engines may perform Boolean and other operations in the course of locating particular information. Search engines may require significant time to perform a search. Indices that reduce the time required to perform a search are generally beneficial.

This patent is subject to a terminal disclaimer.

International Business Machines Corporation


A flat type capacitor-use polypropylene film having a Ad(thickness determined by micrometer method—thickness determined by weighing method) of 0.05-0.2 μm and a lengthwise shrinkage dimensional change rate of 3% or less, or a flat type capacitor-use polypropylene film having a Δd of 0.1-0.3 μm and a lengthwise F5 value of 50 MPa or more, and a flat type capacitor using it. A film excellent in handling ability in a capacitor element winding process is obtained, and a small, a large-capacity flat type capacitor excellent in withstand voltage characteristics such as self-recovering property, and used suitably under a high rated voltage, is obtained.

A polypropylene film is broadly applied to electric use because it is more excellent in withstand voltage characteristics and electric properties such as dielectric loss than other plastic films. In particular, increase of demand as a dielectric material in the use of capacitors is remarkable. Recently, as various electric devices are made as a inverter formation, and further, as making a capacitor small-sized and large-capacity is accelerated, making a polypropylene film thinner is further required.
However, since a polypropylene film is a material poor in stiffness among plastic films used for capacitors, as its thickness is decreased, requirement of improvement of its handling ability and processing property has been increased. Therefore, various improvements of the handling ability and processing property have been proposed.
For example, a capacitor-use deposited polypropylene film is proposed, wherein a static friction coefficient at 80° C. between a non-deposited surface of a polypropylene film after metal deposition on the other surface of the film and a metal plate plated with chrome is 0.8 or less, and the content of an additive with a melting point of 130° C. or lower is 4,000 ppm by weight or less, and it is known to improve a property for the deposition by it (for example, JP-A-2-170406).
Further, known is a method for carrying out a surface treatment to a non-deposited surface at a wetting tension of 33 dyne/cm or less and giving the film a high-speed winding ability (for example, JP-A-58-16415). Furthermore, a polyester film is proposed wherein its F5 value is 11.0 kgf/mm2 or more and the content all particles in the film is in a range of 0.25-0.60 wt %, and it is known to improve the winding property and the slitting property (for example, JP-A-2000-204177).
Further, known is a method for suppressing reduction of withstand voltage and number of insulation defects of a film by controlling a difference Δd between a film thickness determined by micrometer method and a film thickness determined by weighing method in a range of 0.01-0.5 μm (for example, JP-A-10-156938). Furthermore, known is a method for controlling a ratio MMV/WMV of a micrometer thickness (MMV) to weight mean thickness (WMV) in a range of 1.2-1.6, thereby improving flowability between layers of insulation oil at the time of winding a film in an overlapping form (for example, JP-A-2001-118430).
However, in the capacitor-use deposited polypropylene film described in JP-A-2-170406, an effect for suppressing shift of winding in a capacitor element winding process is poor and insufficient. Further, in the method described in JP-A-58-16415, an effect for suppressing generation of wrinkles in a capacitor element winding process is insufficient, and in particular, it is remarkable in a thin film having a thickness of 4 μm or less. Furthermore, because the film described in JP-A-2000-204177 is a polyester film, it is difficult to apply the technology to a polypropylene film from the viewpoint such as a difference between polymer properties.
Further, any proposal is insufficient in withstand voltage characteristic which is one of final targets, especially, in a point for keeping an excellent withstand voltage characteristic for a thin polypropylene film with a thickness of 4 μm or less.
Further, in the method described in JP-A-10-156938, wrinkles generate particularly in a flattening press process of a capacitor element of a thin polypropylene film with a thickness of 4 μm or less, and therefore, it is insufficient in withstand voltage characteristics.
Furthermore, in the method described in JP-A-2001-118430, the porosity between film layers becomes too great, and the withstand voltage characteristics are greatly reduced in a capacitor into which insulation oil is not impregnated.
It could therefore be advantageous to provide a flat type capacitor-use polypropylene film which can suppress generation of shift and wrinkles in a capacitor element winding process or a flattening press process thereafter even if the film is a thin polypropylene film with a thickness of 4 μm or less, which is suitable to make a small-sized flat type capacitor with a large capacity of 500 μF or more for example, which keeps withstand voltage characteristics, in particular, self-recovering property that is one of the characteristics of a flat type capacitor, and which is suitable for use of a direct current rated voltage of 700V or higher, and a flat type capacitor using it.

Flat type capacitor-use polypropylene film and flat type capacitor using it


A wart removing tool which comprises a carbide pad mounted at one end of an elongated handle. The carbide pad has an exterior substantially planar surface which is roughened by being knurled/serrated. The carbide pad is to include cobalt with the carbide being from the group consisting of iron carbide, manganese carbide, chromium carbide, molybdenum carbide, vanadium carbide, tantalum carbide, niobium carbide, titanium carbide and tungsten carbide. The tool is to be utilized by the roughened surface being rubbed against a wart at least twice a day with these rubbings occuring several hours apart. This type of application is to occur for period of time between four and ten weeks during which time the wart will diminish in size until gone from the body.

1) Field of the Invention
The field of this invention relates to a medical type of device and more particularly to a device that can be used to effect removal of warts from an animal body, such as a human body.
2) Description of the Prior Art
A wart is defined as a papillomatous growth which occurs on the surface of the skin of an animal body with generally warts being common within humans. Warts are caused by a virus. Warts are deemed to be undesirable by being unattractive. In the past, there have been numerous lotions that have been designed to be appliable to the wart and, after a period of time, the wart is to drop off of the body. However, in the past, these lotions have proved to be rather ineffective and/or painful. Additionally, it is common to remove warts with an electric needle. The disadvantage of such an electric needle is that it destroys the wart by "burning" which produces a rather unslightly appearance until the area heals which was occupied by the wart. This burning also results in the creating of a permanent unsightly scar. Also, at times, this technique results in the wart regrowing not resulting in the elimination of the wart.


A system for drop detection of fluid drops ejected by a printing device includes a drop detector comprising a radiation source and radiation sensor for illuminating a region in which drops are ejected by a print bar and detecting radiation from the radiation source that is reflected by backscattering from the drops to the radiation sensor; and a controller for controlling the drop detector and the print bar, wherein the controller uses a signal output by the drop detector to determine whether nozzles of the print bar are operating properly.

An inkjet printing device is a fluid ejection device that provides drop-on-demand ejection of fluid droplets through printhead nozzles so as to print images onto a print medium, such as a sheet of paper. It is sometimes desirable to detect characteristics of ink drops ejected by an inkjet printing device. Characteristics of the ink drops may be used to assess the proper operation of the printing device. For example, detecting that ink drops are absent where they should be present and detecting the number, size, shape and/or color of ink drops may help determine whether nozzles through which ink drops are ejected are partially or fully clogged.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.

HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.


An electronic device and method receive (for example, from a memory), a grayscale image of a scene of real world captured by a camera of a mobile device. The electronic device and method also receive a color image from which the grayscale image is generated, wherein each color pixel is stored as a tuple of multiple components. The electronic device and method determine a new intensity for at least one grayscale pixel in the grayscale image, based on at least one component of a tuple of a color pixel located in correspondence to the at least one grayscale pixel. The determination may be done conditionally, by checking whether a local variance of intensities is below a predetermined threshold in a subset of grayscale pixels located adjacent to the at least one grayscale pixel, and selecting the component to provide most local variance of intensities.

Identification of text regions in papers that are optically scanned (e.g. by a flatbed scanner of a photocopier) is significantly easier (e.g. due to upright orientation, large size and slow speed) than detecting regions that may contain text in scenes of the real world that may be captured in images (also called "natural images") or in video frames in real time by a handheld device (such as a smartphone) having a built-in digital camera. Specifically, optical character recognition (OCR) methods of the prior art originate in the field of document processing, wherein the document image contains regions that are black or white or several shades of gray.
Document processing techniques, although successfully used on scanned documents created by optical scanners, generate too many false positives and/or negatives so as to be impractical when used on natural images. For example, FIG. 1A illustrates a bill board 100 in a real world scene in India. A user 110 (see FIG. 1A) may use a camera-equipped mobile device 108 (such as a cellular phone) to capture an image 107 (also called "natural image" or "real world image") of the bill board 100. Camera captured image 107 may be displayed on a screen 106 of mobile device 108. Such an image 107 (FIG. 1A) is normally captured in three colors, such as Red (FIG. 1B), Green (FIG. 1C) and Blue (FIG. 1D), and converted into a grayscale image (FIG. 1E).
When a grayscale image (FIG. 1E) is processed in the normal manner, prior art image processing techniques may result in failure to recognize one or more words. This is because many prior art techniques generate too many false positives and/or negatives so as to be impractical when used on images containing natural features (such as branches of a tree) mixed with text (e.g. in various colors) e.g. on bill boards, traffic signs, store fronts, vehicle license plates, etc. due to variations in lighting, color, tilt, focus, font, etc.
For information on techniques used in the prior art, to identify text regions in color images, see the following articles incorporated by reference herein in their entirety as background:    (a) STROUTHOPOULOS et al, "Text extraction in complex color documents", Pattern Recognition 35 (2002) 1743-1758;    (b) CHEN, et al. "Detecting and reading text in natural scenes," IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'04), 2004, pages 1-8;    (c) JAIN, et al. "Automatic text location in images and video frames", Pattern Recognition, 1998, pp. 2055-2076, Vol. 31, No. 12; and    (d) EPSHTEIN, et al. "Detecting text in natural scenes with stroke width transform," Computer Vision and Pattern Recognition (CVPR) 2010, pages 2963-2970, (as downloaded from "http://research.microsoft.com/pubs/149305/1509.pdf").
Image processing techniques of the type described in such prior art articles appear to be developed under an assumption that text regions have adequate contrast relative to background regions in a grayscale image. Accordingly, use of such techniques on images that do not conform to such an assumption can result in false positives and/or negatives, which thereby render such techniques impractical. Hence, there is a need to improve contrast of a natural image or video frame, for use in text extraction and recognition applications as described below.

Method of improving contrast for text extraction and recognition applications


A method of preventing Hot Carrier Injection in input/output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can tolerate. By placing input/output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. A circuit for preventing Hot Carrier Injection in these input/output devices comprises comparing an input voltage to a reference voltage, and if conditions that would produce Hot Carrier Injection are present (e.g. when input voltage is greater than reference voltage), slowing the turn-on of one of the series connected input/output devices, thereby reducing the voltage from the drain-to-source of another series connected input/output device.

1. Field of the Invention
The present invention relates to integrated circuits (ICs), such as interface circuits, that are designed having reduced feature sizes, for example, 0.13 μm. More particularly, the invention relates to ICs that include interfaces (such as input/output (I/O) circuits) that are capable of interfacing with comparatively high-voltage signals from other sources, for example a 3.3 volt IC interfacing with signals from a 5 volt IC, or any other disparate ranges. Moreover, the invention relates to integrated circuits in which the semiconductor devices are biased such that the stress across the gate-oxides and junctions, as well as the leakage currents, are maintained at tolerable levels.
2. Related Art
The trend in CMOS-based processing technology is to produce integrated circuit (IC) cores having a higher density of semiconductor devices, such as transistors, and faster clock rates than their predecessors. I/O circuits, which electrically couple an IC core to external components, are accessed through I/O circuit pads that surround the IC core. The IC core and the I/O circuit pads are generally fabricated from the same processing technology. There is however no requirement that they comprise the same technology and hybrid circuits are known in the art. The inventive concepts herein are applicable to a variety of fabrication technologies.
The performance of the IC cores may generally be improved by shrinking the feature sizes of the semiconductor devices, for example field-effect transistors (FETs). Unfortunately, reducing the IC feature sizes may proportionally decrease the maximum operating voltage that the semiconductor devices within the IC can withstand. For example, an I/O circuit pad, fabricated from a CMOS process having 0.30 micron features, typically withstands a maximum operating voltage of about 3.6 volts. In such a case the maximum operating voltage of the I/O circuit pad is insufficient to drive the external components which have a higher voltage requirement, such as 5 volts. Furthermore, if the IC is interfaced with a greater than the maximum operating voltage, the IC may fail. If high voltages appear across the drain-to-source of NMOS and PMOS devices when they are in a conducting state, there exists the possibility of Hot-Carrier-Injection (HCI). HCI occurs when, as a result of larger fields along the channel direction, a small fraction of the channel carriers have enough energy to enter the insulating layer near the drain. In N-Channel MOSFETs, energetic electrons entering the oxide create interface traps and oxide wear-out, eventually leading to gate-to-drain shorts. Thus, over time, HCI degrades transistor characteristics. Devices in the IC and devices in I/O circuit are equally susceptible to HCI.
One way to attempt to resolve such requirements of circuits with mismatched voltage requirements is to increase the robustness of the fabrication process, for example by increasing the thickness of the gate-oxide layer of the semiconductor devices which comprise the IC circuitry. A thick gate-oxide layer may provide semiconductor devices, such as FETs, with the ability to support a higher voltage requirement. However, this voltage robustness is commonly accompanied by a decreases the performance of the IC, because the thick gate-oxide layer reduces the overall gain of the devices which comprise the IC. Reducing the gain minimizes the benefit that occurs by reducing the feature size.
Other attempts have included increasing the complexity of the CMOS fabrication process so there are multiple sets of devices where each set meets different voltage requirements. Each set of devices requires a different gate-oxide. Each additional gate-oxide requires a separate mask. The resulting hybrid process may significantly increase the manufacturing costs of the IC.
One way to avoid the drawbacks of the aforementioned processing-based solutions is to use a "level-shift" chip as an external component. The IC core and the I/O circuits are fabricated from the same process. The "level-shift chip" may be fabricated from a process that supports the discrete voltage requirement by stepping up the core output signals to support the discrete voltage range and stepping down the external drive signals to support the IC core voltage range. Such a level-shift chip can be a waste of much needed space on a crowded printed circuit board and may degrade performance.
An I/O circuit that transforms voltages between different voltage levels without degrading the overall performance of the integrated circuit and maximizing use of space on the printed circuit board or multi-chip substrate may be beneficial. It would be a further benefit if such an I/O circuit could use voltages presented at the I/O circuit in order to provide such protective biasing. It would be yet another benefit to protect the devices comprising the I/O circuit itself from potentially damaging voltages that occur during transient conditions.
Commonly an I/O power supply may vary +/−10% and may vary significantly more during transient conditions. When the I/O power supply varies, circuits may have higher stress on the gate-oxides of the devices in the I/O circuit; such stresses may not be desirable in many process technologies. It may be desirable to provide bias voltages to various devices in the I/O circuit such that the device gate-oxide is protected from high-voltages under various conditions of operation even when the power-supply voltage varies by a large amount.
Embodiments of the present invention may be optimized, for example, where 5 volt input tolerance is required, even when the power supplies are varying in steady state by +/−10%.
Embodiments of the present invention are illustrated in an optimized form for I/O circuits where a 5 volt +/−10% input tolerance is required for normal operating range. Additionally the inventive concepts herein are described in terms of CMOS (Complimentary Metal Oxide Semiconductor) integrated circuits. Those skilled in the art will readily appreciate the fact that techniques described with respect to CMOS ICs are readily applicable to any circuits having disparate power supply and/or drive signal requirements for different portions of the circuitry. The CMOS example chosen is one likely to be familiar to those skilled in the art. There is, however, no intent to limit the inventive concepts to CMOS ICs, as the techniques are equally applicable to a wide variety of integrated circuit fabrication techniques.

Hot carrier injection suppression circuit


An implantable system (11) for control of and communication with an implant (17) in a body, comprising a command input device (12) and a processing device (13) coupled thereto, the processing device (13) being adapted to generate input to a command generator (16) which is comprised in the system (11) coupled to the processing device (13) and which is adapted to generate and communicate commands to the medical implant (17) in response to input received from the processing device (13), the system (11) further comprising a memory unit (15) connected to at least one of said devices in the system (11) for storing a memory bank of commands. The command input device (12) is adapted to receive commands from a user as voice commands, and the processing device (13) comprises a filter adapted to filter voice commands against high frequency losses and frequency distortion caused by the mammal body (10).

Medical implants as such are previously known, and are often used to replace or assist an organ or a function in a mammal body. Some medical implants which may be mentioned by way of example are artificial hip joints, pacemakers, artificial insulin pumps and the like.
As will be understood, some medical implants require, or may be improved by, the ability to receive input, either from the patient or medical personnel attending to the patient. Various methods are known for giving such input to implanted devices. For example, U.S. Pat. No. 5,569,186, discloses a system for sending input to an implant via telemetry. In the '186 patent, input can be given as voice commands; if a voice command is successfully recognized by the apparatus, a matching command is then sent by telemetry means to an implantable device in a patient's body.

System for voice control of a medical implant


A floor washing apparatus for removing oil, grease and other residue contaminants from a floor surface includes a housing supported on wheels and a spray suction head removably attachable to the housing so that a suction intake mouth is maintained in close spaced relation above the floor surface as the apparatus as moved on the floor. A wash tank within the housing holds a predetermined charge of wash solution and includes a pump therein to discharge a forced flow of the cleaning solution through one or more nozzles in the spray suction head and onto the floor surface, and a vacuum suction motor for creating a negative pressure within the wash tank to draw the wash solution and contaminant residues removed from the floor surface through the suction intake mouth and an interconnecting flexible hose for return to the wash tank. During a recycling process, a valve assembly releases contaminated wash solution from the wash tank into a distillation chamber where the wash solution is heated to produce vapors. A condenser cools the vapors to a liquid state, yielding non-contaminated, pure wash solution which is directed into a holding tank for subsequent transfer and use in the wash tank.

1. Field of the Invention
This invention relates to an apparatus for washing floors, and more particularly, to a floor washing apparatus structured to discharge and pick up a wash solution in order to remove oil, grease and other contaminant residues from a floor surface, and wherein the apparatus includes means for recycling contaminated, dirty wash solution during a recycling process to produce non-contaminated, pure wash solution for subsequent use during floor washing operations.
2. Description of the Related Art
During the normal day to day operations at various industrial and/or commercial facilities, the floor or ground surface usually becomes contaminated with various residues such as oil and grease. For instance, at an automotive repair facility, oil, grease and other contaminants may drip from vehicles and other equipment onto the floor surface below. At the end of the day, there is often a slippery sheen of residue over much of the garage floor surface presenting both a safety and environmental hazard. To prevent slipping and further contamination, garage floor surfaces are, in most instances, washed regularly with a hose or water pressure cleaner to remove the undesirous film of residue. While this is generally effective to improve safety conditions, the run-off from such washing operations results in large volumes of contaminated water which must be directed to an on site separation reservoir to separate some of the oils and other contaminants from the water used to wash the floor surface. Thereafter, the separated contaminants need to be pumped out of the separation reservoir for transport to a remote contaminant disposal facility. This process of separation and removal of contaminants from the wash run-off is both time consuming and costly to the business owner, requiring a private disposal service to regularly clean out the separation reservoir. Further, the process is not entirely effective in removing contaminants from the floor surface or separation reservoir.
Accordingly, there is an urgent need in virtually all industrial/commercial environments, and some households, for an apparatus structured to remove contaminants such as oil and grease from floor surfaces in a highly efficient, cost-effective manner which does not require the use of a contaminant disposal service for transport of contaminants to a remote disposal site.


A programmable digital baseband receiver that processes a large number of signal waveforms and data rates. Programmable elements of the receiver implement coherent signal detection, automatic gain control and decision processing that permits processing of a large number of signal bandwidth efficient QAM and similar signal formats. The receiver comprises a threshold array having a plurality of programmable complex threshold detectors, and selectable decoder tree logic structures embodied in threshold interpreters. Each programmable complex threshold detector is a fully programmable I, Q threshold detector employing programmable I, Q sign threshold detectors that is adapted to the received complex baseband signal constellation.

The present invention relates generally to digital receivers, and more particularly, to programmable digital baseband receivers employing programmable complex threshold detectors and threshold interpreters.
A traditional DSP digital receiver employed to process multiple waveforms typically uses detection methods including sampling, A/D conversion and digital signal processing. The traditional receiver typically includes a low noise amplifier followed by an intermediate frequency (IF) downconverter that is fed by a local oscillator. The IF signal output of the downconverter feeds an AGC amplifier whose output is bandpass filtered. In a DSP receiver, the IF signal is fed to a digital signal processor.
The digital signal processor (DSP) processes the output of the bandpass filter and includes an IF to complex baseband converter, and a complex analog-to digital (A/D) converter. For digital communications, the signal is fed to a baseband equalizer, a symbol decision circuit, and a symbol decoder. For symbol rate processing, a symbol synchronization circuit is coupled to the complex A/D, baseband equalizer, symbol decision circuit, and symbol decoder to synchronize the sequential processing of symbols by these circuits. The traditional DSP, digital signal receiver is thus implemented using programmable and selectable baseband threshold elements and simple logic trees.
The waveform specifications that determine the details of the DSP-specific processes performed in the traditional DSP digital receiver must be programmed and downloaded into the DSP and other receiver elements. Implementing such a DSP receiver at variable data rates up to 10 Gbps is an expensive and complex process, and requires prime power on the order of several hundreds of Watts.
In view of the above, it is advantageous to have a digital receiver that consumes less power than conventional designs and that is programmable to accommodate a large variety of signal waveforms and data rates. It is therefore an objective of the present invention to provide for programmable digital baseband receivers employing programmable complex threshold detectors and threshold interpreters that implement coherent signal detection, automatic gain control and symbol decision processing to permit processing of a large number of bandwidth efficient QAM signal formats, and the like.

Digital receiver having programmable complex threshold detectors and threshold interpreters


An electrical connector assembly (100) in the present invention comprises an insulative housing (100), a plurality contacts (100) received therein, a placement device (100) in shape of hollow case for positioning the chip module (3) onto the housing (2), wherein the placement (1) defines a number of deformable members (42) to engage with the chip module for simplifying the chip module (3) to be inserted therein.

1. Field of the Invention
The present invention relates to an electrical connector assembly, and more particularly to an electrical connector assembly for securing mounting a chip module to an electrical connector.
2. Description of the Prior Art
Land grid array (LGA) electrical connectors are widely used in the connector industry for electrically connecting LGA chips to printed circuit boards (PCBs) in personal computers (PCs). Conventionally, one kind of the LGA connector mainly comprises an insulative housing, a multiplicity of contacts received therein, The housing defines a multiplicity of terminal passageways in a rectangular array, for interferentially receiving corresponding contacts. In assembly, the terminals are inserted into the passageways of the housing. Secondly, the housing is attached on a printed circuit board. Then chip module is mounted onto the housing by manual for getting an electrical connection between conductive pads of the chip module and the terminals received in the housing. Consequently, the housing and the chip module are usually disengaged for manual operating and the conductive pads and the terminals are usually destroyed by the disengagement between the housing and the chip module.
Thus, there is a need to provide a new electrical connector that overcomes the above-mentioned problems.


The present disclosure provides an array substrate and a manufacturing method thereof, a display panel and a display device. The array substrate according to an embodiment of the present disclosure includes: a base substrate, and a plurality of pixel units located on the base substrate; each pixel unit at least includes a driving transistor and a light-emitting device; the array substrate further includes: a shielding layer located between a layer where a gate of a driving transistor in each of the pixel units is located and a layer where a first electrode of the light-emitting device is located.

Organic Light-emitting Diode (OLED) display panels have advantages of low energy consumption, low production cost, self-luminescence, wide viewing angle, and fast response speed, and are already applied to the display fields of mobile phones, tablet computers, digital cameras, and the like. In general, the OLED display panel adopts a pixel driving circuit to drive an OLED to emit light for display.

Array substrate and manufacturing method thereof, display panel and display device


A non-volatile semiconductor memory device comprises a plurality of memory cells each including a semiconductor substrate of a first conductivity type having a main surface region, a control gate portion formed in said main surface region of the semiconductor substrate and consisting of an impurity diffusion region of a second conductivity type opposite to said first conductivity type, a reading transistor portion formed on the main surface region of the substrate and consisting of a MOS type transistor structure, and a floating gate portion formed over the control gate portion and the reading transistor portion. These memory cells differ from each other in an overlapping area ratio Ap/An, where An denotes an area of an over-lapping portion between the floating gate and the impurity diffusion region of the control gate portion, Ap represents an area of an overlapping portion between the floating gate and an active region of the reading transistor portion.

The present invention relates to a semiconductor device. More specifically, the present invention relates to a non-volatile semiconductor memory device.
In a floating gate type non-volatile semiconductor memory device, a current flowing in a cell under predetermined conditions and a current flowing to a reference transistor are compared by a differential amplifier so as to determine cells in an array by "0" and "1". This reference transistor is called reference cell.
Such a reference cell is generally formed to have the same structure as that of an array cell for the purpose of maintaining a similarity with respect to the cell in array, or into a so-called dummy cell type in which the control gate and the floating gate are connected to each other. In short, a reference cell array serves as a miniature version of cell array.
Also, in a reference which determines an output of a logic device, the reference level is generally limited to the threshold value of the transistor used in the logic device.
Recently, in accordance with diversification in the characteristics of devices, it becomes necessary to make determination in terms of "0", "0.5" and "1" as in the case of, for example, a multi-value memory.
With a conventional approach, in reply to such a demand, a plurality of sense amplifiers having different sense ratios are used to deal with the diversification of devices, that is, a multiplicity in value.
However, with this approach, the circuit area is increased, thereby increasing the chip area and the cost.
For verification in which the threshold value of the memory cell after programming or erase is confirmed, the non-volatile semiconductor memory device changes its verifying voltage in accordance with the state to be verified. However, when a verification is carried out in the above-mentioned manner, the voltage supply circuits are inevitably complicated.
A memory cell can be defined as a circuit of a minimum unit, for storing data in a semiconductor memory device. A memory cell consists of a transistor and a capacitor in combination. A normal semiconductor memory device is required to achieve as small distribution of memory data as possible, its memory cell array consists of a plurality of memory cells of the same type and the same size, so as to obtain as uniform characteristics as possible.
In accordance with an increase in the degree of integration of a semiconductor memory device, there is a tendency for a semiconductor memory device to be required to have not only a function as a mere memory medium but also a function of systematic operation coupled with a CPU. Such a tendency is particularly prominent in a non-volatile semiconductor memory device such as an EPROM, EEPROM or flash memory.
In reply to such requirements, it is proposed that a memory cell array of a semiconductor memory device is divided into a plurality of blocks, which are allowed to have different functions from each other, for example, as inn a bootblack mode of Intel Co. In this mode, the blocks have different functions from each other, and therefore the characteristics required from memory cells are different from one block to another. More specifically, a block in which a basic code such as for standing a system is input, involves a less number of times of rewriting of data, and therefore is required to have memory cells of a mask ROM type, whereas a block in which data is frequently rewritten, requires to have memory cells having excellent programming characteristics.
However, in a conventional semiconductor memory device, a memory cell array consists of memory cells which have the same characteristics. Consequently, a variety of requests as mentioned above cannot be satisfied. In the case where memory cells are formed to have the characteristics suitable for one block, these memory cells may cause a trouble in another block. For example, in the case where all the memory cells of a memory cell array is formed to have a large gate couple ratio, so as to improve the programming characteristics, those memory cells which belong to a block used for inputting a basic code are easily exposed to problems such as gate-disturb and soft-write.

Non-volatile semiconductor memory device


A bracket assembly includes a first bracket and a second bracket. The first bracket includes a first support segment, a second support segment, and a third support segment. The first support segment has an upper portion and a lower portion. The second support segment extends in a first direction from the upper portion of the first support segment. The third support segment extends in the first direction from a portion of the first support segment that is adjacent to the lower portion of the first support segment. The first to the third support segments jointly define a support passage. The first bracket is used to support an object. The second bracket is mounted in the support passage of the first bracket.

U.S. Pat. No. 6,230,903 discloses a bracket assembly invented by Ryan Abbott, which includes a first mounting bracket 27 and a second mounting bracket 47 as shown in FIG. 2 accompanying the specification of the patent. The first mounting bracket 27 is provided with a plurality of elongated slots 33, and the second mounting bracket 47 is provided with a plurality of elongated slots 53. A plurality of studs 31 are provided on a slide mechanism 21, extend through the elongated slots respectively, and are connected with a plurality of nuts 29 respectively to allow adjustment of the distance between the first mounting bracket 27 and the second mounting bracket 47 and to enable the two mounting brackets 27 and 47 to carry a chassis via the slide mechanism 21.
The foregoing bracket assembly, however, cannot carry a chassis directly, i.e., without the slide mechanism. This constitutes a limitation on the applicability of the bracket assembly where budget is limited or where the server to be mounted via the bracket assembly has special requirements in terms of mounting specifications.


A retroviral vector comprising a retrovirus with infectivity for birds and/or mammals in which at least part of the genomic RNA sequences carrying information for the production of viral proteins required in trans for retroviral replication have been replaced by one or more sequences carrying information to be introduced in a target cell chromosome, characterized in that the primer binding site (PBS) has been modified to a sequence that does not allow strong base pairing with the 3' end or other priming sequence in any naturally occurring tRNA. The present application is directed to the tRNA-like primer.

Retroviral vectors are gene transfer vehicles for birds and mammals that exploit features of the retrovirus replication cycle such as high infection efficiency and stable co-linear integration of the virally transmitted information in a target cell chromosome. Retroviral vectors are becoming important tools in basic research, biotechnology and gene therapy.
Most retroviral vectors currently in use are derived from Murine Leukemia Viruses (MLVs). MLVs are particularly suitable as vectors due to their well-documented pattern of transcription in diverse cell types and relatively simple modular genetic structure.
1. Retroviral structure Retroviruses belong among the enveloped viruses (FIG. 1). The bilipid envelope is derived from the host cell membrane and modified by the insertion of the viral surface protein (SU) and transmembrane protein (TM). The matrix protein (MA) is situated just under the outer membrane surrounding the inner core. The core consists of capsid protein (CA). Inside the capsid are two copies of the retroviral genome which are attached to each other at the 5' end via hydrogen bonding. The virus core particle also contains the viral enzymes: reverse transcriptase (RT), protease (PR), and integrase (IN), and the nucleocapsid protein (NC) which is bound to the viral genome. Besides these proteins encoded by the virus, the virion also contains a number of tRNA molecules derived from the host cell tRNA population.
Murine leukemia viruses (MLV) belong to the simple retroviruses. Retroviruses have a characteristic genomic map: Two long terminal repeats (LTRs) flanking the three structural genes gag, pol and env (FIG. 2). The LTRs can be subdivided into three regions: The U3 region containing the enhancer and promoter elements recognized by the cellular transcription machinery, the R region which play an important role during reverse transcription and furthermore contains the polyadenylation signal, and the U5 region containing sequences of importance in reverse transcription aid packaging of the retroviral genome. Additionally, the LTRs contain cis elements, the inverted repeats, important during the process of integration (FIG. 3).
The integrated provirus gives rise to two mRNA transcripts, a full-length mRNA encoding the gag-, and the gag-pol poly-proteins, and a spliced mRNA encoding the envelope glycoproteins. The full-length mRNA also serves as the genomic RNA and, besides the already described components of the LTR moieties, contains three important cis elements in the 5' untranslated sequence. The primer binding site (PBS), situated downstream from the U5 region, consists of 18 nucleotides complementary to the 3' end of the primer tRNA molecule. Also located in the 5' untranslated region, between the PBS and the beginning of the gag open reading frame, is the packaging signal (.PSI.). The 5' untranslated region furthermore contains a dimer linkage domain responsible for the dimerization of the two viral genomes in the virion. Immediately upstream from the U3 region is another important cis-element, the polypurine tract (PP), which consists of a stretch of A and G residues. This element serves as a site for priming plus-strand DNA synthesis during reverse transcription.
2. The retroviral lifecycle
The retroviral lifecycle is outlined in FIG. 4. Two different mechanisms have been proposed to explain the entry of the virus particle into the host cytoplasm. Most retroviruses, including MLV, are thought to enter the host cell through receptor-mediated endocytosis, a process in which the whole enveloped virus particle is internalized into an endosomal body. The receptor molecule for the ecotropic murine leukemia viruses has been cloned and identified as a cationic amino acid transporter.
After the viral core particle has entered the cytoplasm of the host cell, all enzymatic functions leading to the integrated double-stranded DNA provirus are managed by viral proteins synthesized in the previous host cell and brought along in the virion. The fate of the viral proteins after entry of the core particle is not clear, but the reverse transcriptase, the integrase and the capsid protein remain with the RNA genome forming the nucleoprotein complex in which reverse transcription occurs. Recently, also the matrix protein has been found in association with the nucleoprotein complex.
Following reverse transcription, the nucleoprotein complex migrates to the host cell nucleus. The mechanism responsible for the nuclear localization is unclear, although evidence from Rous sarcoma virus (RSV) suggests the IN protein to be important since the RSV IN protein, when produced in mammalian cells, is localized in the nucleus. Entry of the nucleoprotein complex into the nucleus requires mitosis, probably because the nucleoprotein complex cannot penetrate the nuclear envelope. Once in the nucleus, integration is mediated by the IN protein. The IN protein recognizes the conserved inverted repeats at the ends of the LTRs and removes 2 bases from the 3' hydroxyl termini of both strands. The IN protein also catalyzes a cleavage in the host DNA and mediates the connections between the proviral DNA and the host DNA. As for the specificity of integration no consensus host DNA target sequence has been found, although a tendency to integrate near DNase I-hypersensitive sites has been reported.
For the simple retroviruses (including MLV) transcription and translation is performed by the host cell machinery. Complex viruses (including HIV and HTLV) encode transactivating proteins involved in transcriptional regulation. The assembly of MLV particles takes place at the host membrane, and the process coincides with the budding process. In mammalian B and C type viruses (MMTV and HTLV, respectively) viral core particles are assembled in the host cell cytoplasm. Encapsidation of the viral genomic RNA is mediated through binding of the cis-acting encapsidation signal and the NC moiety of the Gag- or the Gag-Pol precursor protein.
After budding, the Gag- and Gag-Pol polyproteins are cleaved by viral protease (PR). Maturation of the viral proteins results in an overall change in virion morphology. In addition to proteolytic cleavage of the viral polyproteins following budding, the genomic RNA also undergoes a maturation process resulting in a compact dimeric genome.
3. Reverse transcription
The enzyme reverse transcriptase was discovered in 1970, and the current model of reverse transcription was proposed in 1979 (Gilboa et al. 1979). In addition to a DNA polymerase that can copy either RNA or DNA templates, reverse transcriptase contains an RNase H which selectively degrades RNA in RNA/DNA hybrids.
Retroviruses utilize a cellular tRNA molecule as a primer during reverse transcription. Different retroviruses utilize different tRNA species as primers in reverse transcription. Murine leukemia viruses (MLVs) and human T-cell leukemia virus (HTLV) use a proline-tRNA primer, human immunodeficiency virus (HIV) and mouse mammary tumor virus (MMTV) utilize a lysine-tRNA primer, whereas avian leukosis sarcoma virus (ALSV) use a tryptophan-tRNA molecule as a primer for reverse transcription. However, within a given group of retroviruses, the sequence of the primer binding site is highly conserved during retroviral replication, where the 3' 18 nucleotides of the tRNA molecule are copied during plus-strand synthesis. Furthermore, during the viral life cycle the tRNA primer is likely to specifically interact with viral proteins and the viral genome during the processes of packaging, annealing, and reverse transcription. Specific interactions between the tRNA primer and the viral proteins reverse transcriptase and the nucleocapsid protein, as well a secondary interactions between the tRNA and viral genomic RNA have been demonstrated in several viruses.
In a recent article (Lund et al. 1993) the present inventors have altered the MLV wild-type PBS matching a proline-tRNA to sequences matching either a glutamine- or a lysine-tRNA. The effect of the altered PBS sequences was studied by single cycle replication of a retroviral vector, enabling them to quantify the effect of the introduced mutations. The structure of the transduced PBSs was analyzed by amplification of proviral vectors followed by direct sequencing of the PBS and surrounding DNA. They found that MLV can replicate by using various tRNA molecules as primers and concluded that primer binding site-tRNA primer interactions are of major importance for tRNA primer selection, but that efficient primer selection does not require perfect Watson-Crick base pairing at all 18 positions of the primer binding site. Later they have proved that MLV can also replicate by using the methionine (initiator)-tRNA as the primer.
The tRNA primer is packaged in the virion during virus assembly, and originates therefore from the previous host cell. The tRNA primer molecule interacts through base pairing with a region of the genomic RNA (the primer binding site) situated downstream from the U5 region at the 5' end of the genome (FIG. 5). In murine leukemia viruses 18 bases from the aminoacceptor stem and the T.PSI.C loop of the tRNA are annealed to the PBS and the reverse transcription of the retroviral genome is initiated from the 3' end of the tRNA molecule. From here reverse transcriptase synthesizes the first DNA, the minus-strand strong stop DNA. The 3' end of the minus-strand strong stop DNA contains a copy of the R region complementary to the 3' R region of the genomic RNA. The newly synthesized DNA is thought to relocate to this region (first jump) from where minus-strand DNA synthesis can proceed. As the growing minus-strand is synthesized, RNase H continues to degrade the viral RNA. A fragment of the viral RNA, situated at the polypurine tract (PP), is left and acts as the primer for plus-strand DNA synthesis. Plus-strand DNA synthesis proceeds through U3, R and U5 and copies the bases of the tRNA molecule that are complementary to the PBS. At position 57 in the tRNA molecule the reverse transcriptase encounters a modified nucleotide (m.sup.1 A), which it presumably cannot use as a template, and synthesis of the plus-strand terminates. RNase H removes the overhanging part of the tRNA molecule. The remaining part of the plus-strand, leading to the complete double-stranded DNA provirus, is primed by the first part after a relocation event where the two complementary copies of the PBS interact through base pairing. Resulting from this complex reaction is a double-stranded DNA provirus, which is longer than the RNA template due to the copying of repetitive sequences U3 and U5.
4. Retroviral vector systems
A central element in this invention is a retroviral vector propagation system in which infectious, recombinant virus particles can be produced without contamination with replication competent wild type virus. The main advantage of retroviral vectors is the utilization of the efficient infection and integration processes developed in the viruses through evolution.
The proviral genome of MLV can be divided into sequences that are required in cis or in trans for viral replication (FIG. 6). The cis-acting elements are located at the ends of the proviral genome and encompass the U3, R and U5 regions, the inverted repeats in U3 and U5, the PBS, the polypurine tract and she packaging signal. These sequences contain all the elements needed for correct reverse transcription and integration and make up the minimal requirements for a retroviral vector. The space needed for the insertion of foreign DNA is created by deleting the sequences encompassing the open reading frames gag, pol and env.
For most applications it is essential that the retroviral vectors used for gene transfer are unable to generate new virus progeny in the target cell. This requires that the vector constructs are replication defective, the components required to complete the life cycle being supplied from loci outside the vector construct in the virus producing cell.
If these components are not present in the target cell, further virus generation is not possible. However, replication competent viruses may arise as a result of recombination. Such virus may eventually have pathological consequences including the malignant transformation of the infected target cell.
Retroviral vectors are normally propagated by the use of specialized packaging cell lines. In such packaging cell lines all trans-acting virus-encoded components are produced from loci outside the vector construct.
The first packaging cell line was constructed by Mann et al. (1983). This cell line (.psi.-2), containing a Moloney-MLV proviral genome with a 350 bp deletion overlapping the packaging signal, produces all the viral proteins needed in trans for virion production (FIG. 7A). After transfection into this cell line, retroviral vectors carrying the necessary cis-signals will be packaged into infectious virions (FIG. 7B). Although the early packaging cell lines .psi.-2 (Mann et al. 1983) and .psi.-AM.sup.1 (Cone & Mulligan 1984) have been used successfully in a large number of studies, they suffer from important deficiencies. Despite the deletion of the packaging signal replication competent viruses may arise, presumably as a result of recombination between the packaging construct and introduced vector sequences or viruses endogenous to the genome of the packaging cell (Miller 1990). Recombination occurs at high frequency in retroviral replication. The rate of homologous recombination between two heterologous genomes packaged in the same virion has been estimated to range as high as 10 to 30% for each round of replication. A number of studies have reported recombination between introduced viruses or vectors and homologous sequences endogenous to the host cell. Further evidence that deletion of the packaging signal is not sufficient to prevent packaging, comes from a study of a retroviral vector without a packaging signal where packaging and transfer of this vector was easily detected, even though the transduction rate was 3000 fold lower than that of a vector containing the packaging signal. Obviously, the 350 bp deletion in the 5' untranslated region does not inhibit packaging, a fact supported by reports indicating that sequences within the gag open reading frame and within the U5 region also may play a role in the encapsidation process. Furthermore, retroviral particles also package non-viral RNA, indicating that both specific recognition and a more general affinity for RNA is involved in the encapsidation process. Moreover, only a single recombination event is needed to restore the packaging signal and regenerate replication competent viruses. There are several reports of helper virus regeneration resulting from homologous recombination between the packaging construct and either introduced vectors or endogenous viral sequences. FNT .sup.1 The .psi.-AM packaging construct resembles .psi.-2 but expresses another env gene giving rise to recombinant viruses with an amphotropic host range.
To further reduce the risk of generation of complete viruses by recombination in the packaging cells, second generation packaging cell lines have been constructed. The main advantage of these new packaging cell lines is that the packaging construct has been divided into two separate constructs; one encoding the gag-pol polyprotein and one carrying the env gene (FIG. 8). By splitting the packaging construct the risk of recombination is greatly reduced (Miller 1990). By reducing the sequence homology of the packaging construct to the introduced vectors and endogenous MLV-like sequences the risk of homologous recombination can be further reduced.
However, not only the engineered parts of the packaging cells but also endogenous retroviral sequences in the DNA of the packaging cell as well as in the target cell may have to be considered in safety assessments. The risk of a contribution from endogenous retroviruses may be reduced by use of packaging cells based upon cell lines from other species where the endogenous retroviral elements may be more divergent. The current packaging cell technology has recently been reviewed (D. Valerio 1992).
A recent publication (Chapman et al. 1992) describes that the yeast retrotransposon Tyl uses tRNA.sub.i.sup.Met as a primer for Ty1 reverse transcription, and that mutations in the Ty1 element that alter 5 of the 10 nucleotides that are complementary to the tRNA.sub.i.sup.Met abolish Ty1 transposition. When a yeast strain is constructed which lacks wild-type tRNA.sub.i.sup.Met and is dependent on a mutant derivative of tRNA.sub.i.sup.Met that has an altered acceptor stem sequence, engineered to restore homology with the Ty1-PBS mutant, the compensatory mutations made in the tRNA.sub.i.sup.Met alleviate the transposition defect of the Ty1-PBS mutant. The mutant and wild-type tRNA.sub.i.sup.met are enriched within Ty1 virus-like particles irrespective of complementarity to the Ty1-PBS, and from this the authors conclude that complementarity between the Ty1-PBS and tRNA.sub.i.sup.met is essential for transposition, but is not necessary for packaging of the tRNA inside virus-like particles.

Retroviral vector, a replication system for said vector and avian or mammalian cells transfected with said vector


An integrated suspension assembly including interconnect is used to provide an electrical and mechanical connection between an actuation system and a slider. The suspension assembly includes a multi-layer laminate substrate having a base layer, an insulator layer and a conductor layer. The laminate substrate further includes an attachment region for attaching the suspension assembly to an actuator arm, a load beam region, a flexure region for supporting the slider, and an interconnect path. The interconnect path extends along the flexure region, the load beam region and the attachment region wherein the path terminates at the attachment region at a connection point to provide an electro-mechanical attachment to the actuator arm.

The present invention relates to a low cost suspension assembly. In particular, the present invention relates to a one-piece integrated suspension assembly to provide mechanical and electrical connection between an actuator arm and a slider supporting a read/write head for a disc drive actuation assembly.
Generally, a magnetic disc drive includes a magnetic disc and a magnetic read/write head. When the disc rotates, the read/write head reads and writes magnetic signals on circular tracks of the disc. The read/write head is typically mounted on a slider, which is supported by a flexure or head gimbal assembly. The flexure is mounted to a suspension or load beam, which biases the slider toward the surface of the rotating disc. This biasing is sometimes referred to as "pre-loading". The load beam is attached to an actuator arm of an actuator at an attachment plate, or base plate. The actuator arm moves the read/write head over the spinning disc during operation.
A typical prior art suspension assembly is comprised of four components, an attachment plate, a load beam, a flexure and an interconnect, including a flex circuit material and metal trace. One end of the load beam is attached to the actuator arm at the attachment place, oftentimes by swaging. A flexure is attached to an opposite end of the load beam, oftentimes with an adhesive and/or welding, and the slider is mounted to a bottom surface of the flexure. The interconnect is attached to bottom surfaces of the flexure, the load beam and the attachment plate to form an electrical connection path from the slider to the actuator arm. First, a flex circuit material is deposited upon the bottom surface of the suspension assembly, either the entire surface or a portion defining the interconnect path. Second, a metal trace is deposited upon the flex circuit material to provide the electrical connection between the slider and the actuator arm. The flex circuit material insulates the metal trace from the suspension assembly. Alternatively, a pre-fabricated interconnect is attached to the bottom surfaces of the suspension assembly.
Other prior art suspension assemblies include integrated components to improve performance by decreasing the number of suspension components, however, none include a low cost, one-piece, or single component, suspension assembly. For example, some suspension assemblies include an integrated load beam and flexure, an integrated flexure and interconnect, an integrated load beam, flexure and interconnect, or an integrated attachment plate, load beam and flexure. These suspension assemblies require extra assembly processes to complete the suspension assembly prior to attaching the assembly to the actuator arm or mounting the slider. Examples of extra assembly processes include, attaching the attachment plate to the load beam for connection to the actuator arm, attaching the load beam to the flexure and/or attaching the interconnect to the suspension assembly.
As the disc drive industry advances technologically, each element of the disc drive assembly is becoming increasingly integrated, and space and assembly costs are at a premium. It is desirable to integrate the components of the suspension assembly into a single piece to provide mechanical and electrical connections between the slider and the actuator arm and a simpler, less expensive suspension assembly.

One-piece suspension assembly including interconnect


Optically clear stretch releasing pressure sensitive adhesive films containing a silicone pressure sensitive adhesive composition and a tacky tab are provided. The pressure sensitive adhesive compositions are formed from elastomeric silicone polymer selected from the group consisting of urea-based silicone copolymers, oxamide-based silicone copolymers, amide-based silicone copolymers, urethane-based silicone copolymers, polydiorganosiloxane polymers, or mixtures of these copolymers. The pressure sensitive adhesive compositions may also contain an MQ tackifying resin. The pressure sensitive adhesive compositions may be used to form adhesive articles.

Stretch releasing adhesive tapes are often used to bond to a substrate and then release from the substrate upon stretching. Stretch releasing adhesive tapes are useful in a variety of applications including, e.g., assembling, joining, attaching and mounting applications. The stretch releasing tape can be removed from the substrate by stretching the tape at an angle to the surface of the substrate to which it is bonded.
Many stretch releasing adhesive tapes, once bonded to a substrate, e.g., wallboard, are cleanly removable from the substrate such that there is no visible residue remaining on the substrate and no visible damage to the substrate.

Stretch releasing optically clear pressure sensitive adhesive


A silicone rubber composition comprising (A) an organopolysiloxane, (B) an inorganic filler, typically fumed silica, and (C) a specific halogen-free organic peroxide, typically 1,6-bis(p-toluoylperoxycarbonyloxy)hexane or 1,6-bis(benzoylperoxycarbonyloxy)hexane is safe and lends itself to atmospheric hot air vulcanization so that it can be extrusion vulcanized into silicone rubber having satisfactory physical properties without voids or surface tack. The silicone rubber composition is extrusion molded around an electrical wire, constructing a covered wire.

This invention relates to a silicone rubber composition of the organic peroxide curing type, especially such a silicone rubber composition suited for wire coating, a silicone rubber sponge composition, and a silicone rubber-covered wire.
In the prior art, silicone rubber compositions of the organic peroxide curing type use organic peroxides such as bis(2,4-dichlorobenzoyl)peroxide, 2,5-di(t-butylperoxy)hexane and dicumyl peroxide as the curing agent. An appropriate type and amount of curing agent is selected and used depending on the molding technique of a silicone rubber composition as well as molding temperature and other conditions, and the type of silicone rubber.
Of these organic peroxide curing agents, bis(2,4-dichlorobenzoyl)peroxide is a superior curing agent and widely used in the industry. This is because bis(2,4-dichlorobenzoyl)peroxide is stable at room temperature, achieves the fastest vulcanization as compared with other curing agents and offers high productivity. As the significant feature, this curing agent is most effective under atmospheric hot air vulcanization (HAV) conditions.
However, bis(2,4-dichlorobenzoyl)peroxide produces chlorine by-products when thermally decomposed. The molding time is undesirably prolonged because long-term heat treatment is needed to remove the chlorine by-products. It is believed from the environmental standpoint that the use of peroxide curing agents which will form such chlorine by-products becomes difficult or inhibited.
From such a standpoint, there is a need for a peroxide curing agent substitute for bis(2,4-dichlorobenzoyl)peroxide. JP-A 62-185750 discloses bis(p-methylbenzoyl)peroxide as the halogen-free peroxide curing agent. JP-A 63-130663 discloses 1,3-bis(t-butylperoxy-carbonyloxy)-2,2-dimethylpropane as a halogen-free peroxide curing agent. These peroxide curing agents have high decomposition temperatures and suffer from the drawbacks of a slow vulcanization rate and poor productivity.
For the vulcanization of wire coating silicone rubber compositions, various techniques are used depending on the type of silicone rubber composition and the physical properties required for the cured rubber. In general, heat treatment in the presence of organic peroxides is widely used. Such organic peroxides include benzoyl peroxide, bis(p-chlorobenzoyl)peroxide, bis(2,4-dichlorobenzoyl)peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl perbenzoate, and t-butyl cumyl peroxide. As the vulcanizing agents which ensure that cost effective silicone rubber-covered wires having good properties are manufactured through extrusion hot air vulcanization, bis(2,4-dichlorobenzoyl)peroxide and other halogen-containing peroxides are customary. However, when halogen-containing organic peroxides are used, decomposed products thereof are left in molded parts after curing, which will bleed out on the surface with the lapse of time. Because of their own poisoning effect, long-term post-curing is necessary.
To solve these problems, for example, JP-A 59-18758 proposes the use of bis(o-methylbenzoyl)peroxide as the curing agent in silicone rubber compositions. The use of bis(p-methylbenzoyl)peroxide is also proposed as the curing agent in silicone rubber compositions. These curing agents in the form of methyl-substituted benzoyl peroxide have a high decomposition temperature and a low vulcanization rate so that silicone rubber compositions using such curing agents tend to generate voids upon curing. As a consequence, silicone rubber molded parts often have varying physical properties, and coated wires undergo a lowering of breakdown voltage such as spark-over.
Meanwhile, silicone rubber sponge has physical properties inherent to silicone rubber as well as excellent properties including heat resistance, freeze resistance, electrical insulation, flame retardance and compression set. Basically, silicone rubber sponge is manufactured by combining a heat-curable silicone rubber composition with a curing agent and a blowing agent, and heating the composition for blowing and curing, thereby forming a sponge. In this process, a blowing ability, a uniform fine cell structure, and a skin layer having a smooth tack-free surface are important, and the physical properties inherent to silicone rubber must be retained.
With respect to the molding method, the compositions are cured and expanded in atmospheric hot air so that continuous molding is possible. Organic peroxides enabling atmospheric hot air vulcanization are generally halogen-containing peroxides such as bis(2,4-dichlorobenzoyl)-peroxide. When halogen-containing organic peroxides are used, there arise the problems that decomposed products left in molded parts after curing will bleed out on the surface with the lapse of time, and long-term post-curing is necessary because of the decomposed products"" own poisoning effect as previously mentioned.
Halogen-free benzoyl peroxide allows for atmospheric hot air vulcanization, but fails to provide satisfactory sponge properties with respect to expansion and cell structure.
Then JP-A 10-182972 proposes the use of alkyl-substituted benzoyl peroxides as a halogen-free curing agent. These peroxides have a high decomposition temperature and a low vulcanization rate, leading to low productivity, and fail to provide satisfactory sponge properties with respect to expansion and cell structure.
Therefore, an object of the invention is to provide a silicone rubber composition, especially for electrical wire coating, which has a high vulcanization rate and hygienic safety, and can be extrusion vulcanized in a continuous atmospheric hot air vulcanization manner into a silicone rubber part without voids or surface tack. Another object is to provide a silicone rubber-covered wire using the silicone rubber composition and having improved withstand voltage properties.
A further object of the invention is to provide a silicone rubber sponge composition which can be cured with halogen-free organic peroxides without detracting from working efficiency and has a reduced post-cure time, as compared with halogen-containing organic peroxides, and which is effectively expandable into a silicone rubber sponge having a uniform fine cell structure and a skin layer with a smooth, tack-free surface.
It has been found that when organic peroxides of the following structural formula (2), which are halogen free, are used as the curing agent in silicone rubber compositions, these organic peroxides create no environmental problem, have a high vulcanization rate satisfactory for productivity, and function well under atmospheric hot air vulcanization conditions. These organic peroxides are thus effective for producing silicone rubber or silicone rubber sponge with satisfactory physical properties. When wires are covered with the silicone rubber compositions, extrusion vulcanization can be effected without giving rise to such problems as voids and surface tackiness, and the resulting silicone rubber coating has improved withstand voltage properties. The invention is predicated on these findings.
According to the invention, there is provided a silicone rubber composition comprising (A) an organopolysiloxane of the average compositional formula (1), (B) an inorganic filler, and (C) an organic peroxide of the structural formula (2).
R1aSiO(4xe2x88x92a)/2xe2x80x83xe2x80x83(1)
Herein R1 is a substituted or unsubstituted monovalent hydrocarbon group and xe2x80x9caxe2x80x9d is a positive number of 1.8 to 2.3.
Herein R2 is independently hydrogen or alkyl, R3 is alkylene, and n is an integer of 1 to 3.
Also provided herein is a silicone rubber-covered wire comprising a wire around which the silicone rubber composition has been extrusion molded.
The invention also provides a silicone rubber sponge composition further comprising (E) an organic blowing agent in addition to the above components.
Component (A) of the silicone rubber composition according to the invention is an organopolysiloxane of the average compositional formula (1).
R1aSiO(4xe2x88x92a)/2xe2x80x83xe2x80x83(1)
In formula (1), R1 which may be the same or different is a substituted or unsubstituted monovalent hydrocarbon group, preferably of 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, for example, alkyl groups such as methyl, ethyl, propyl and butyl, cycloalkyl groups such as cyclohexyl, alkenyl groups such as vinyl, allyl, butenyl and hexenyl, aryl groups such as phenyl and tolyl, aralkyl groups such as benzyl and xcex2-phenylpropyl, and substituted ones of the foregoing groups in which some or all of the hydrogen atoms attached to carbon atoms are replaced by halogen atoms, cyano groups or the like, such as chloromethyl, trifluoropropyl and cyanoethyl. The letter xe2x80x9caxe2x80x9d is a positive number of 1.8 to 2.3, preferably 1.95 to 2.05. The organopolysiloxane should preferably have at least two alkenyl groups attached to silicon atoms in a molecule. The content of alkenyl groups is preferably 0.001 to 5 mol %, especially 0.01 to 0.5 mol % based on the R1 groups. With respect to the molecular structure, the organopolysiloxane is generally of straight chain although it may have in part branched siloxane skeletons. The degree of polymerization is in the range which is known in the art as the range of organopolysiloxane gum, and typically in the range of about 3,000 to 20,000, especially about 5,000 to 10,000. The organopolysiloxane is preferably end-capped with a triorganosilyl group such as vinyldimethylsilyl, divinylmethylsilyl or trivinylsilyl.
Component (B) is an inorganic filler which may be selected from conventional fillers used in silicone rubber. Useful fillers include finely divided silica, quartz flour, magnesium oxide, diatomaceous earth, calcium carbonate, and carbon black, with the finely divided silica being preferred. Silica powder has a specific surface area as measured by the BET method of at least 50 m2/g, especially 100 to 400 m2/g. Wet silica and fumed silica (dry silica) are especially preferred. For wire coating compositions and sponge compositions, fumed silica is preferred among others. Reinforcing silica which can be used herein is commercially available under the trade name of Aerosil 130, 200, 300 and 380 from Nippon Aerosil K.K., Cab-O-Sil MS-5, MS-7, HS-5 and HS-7 from Cabot Corp., Santocel FRC and CS from Monsanto Co., and Nipsil VN-3 from Nippon Silica Industry K.K. These fillers may be used with or without surface treatment with organopolysiloxanes, organopolysilazanes, chlorosilanes or alkoxysilanes. The amount of the filler used herein is not critical and preferably ranges from about 5 to 200 parts by weight per 100 parts by weight of the organopolysiloxane (A). An appropriate amount of finely divided silica is about 5 to 100 parts, more preferably about 10 to 90 parts, and especially about 30 to 80 parts by weight per 100 parts by weight of the organopolysiloxane (A).
Component (C) is an organic peroxide of the structural formula (2).
In formula (2), R2 which may be the same or different is independently selected from hydrogen and alkyl groups, preferably of 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, such as methyl, ethyl, propyl and butyl. R3 is selected from alkylene groups, preferably of 1 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, such as methylene, ethylene, propylene, butylene and hexylene. The letter n is an integer of 1 to 3.
Specifically the organic peroxides of structural formula (2) include 1,6-bis(p-toluoylperoxycarbonyloxy)-hexane of the following structural formula (3), 1,6-bis(benzoylperoxycarbonyloxy)hexane of the following structural formula (4), 1,6-bis(p-toluoylperoxycarbonyloxy)butane, and 1,6-bis(2,4-dimethylbenzoylperoxy-carbonyloxy)hexane.
In order that the organic peroxide of formula (2) be admixed with a compound comprised of the organopolysiloxane (A) and the filler (B) in a safe manner, the organic peroxide may take the form of a paste in an inert carrier, preferably a diorganopolysiloxane compatible with the compound such as polydimethylsiloxane, prior to use. An appropriate amount of the organic peroxide of formula (2) is about 0.1 to 10 parts, and especially about 0.2 to 5 parts by weight per 100 parts by weight of the organopolysiloxane (A).
By blending (E) an organic blowing agent, the silicone rubber composition of the invention can be formulated as a silicone rubber sponge composition.
Examples of the organic blowing agent (E) include organic azo compounds such as azobisisobutyronitrile, 2,2xe2x80x2-azobis-2-methylbutyronitrile, 2,2xe2x80x2-azobis-2,4-dimethylvaleronitrile, 1,1xe2x80x2-azobis(1-acetoxy-1-phenylethane), and azodicarbonamide; nitroso compounds such as dinitropentamethylene tetramine; and hydrazine derivatives such as 4,4xe2x80x2-oxybis(benzenesulfonylhydrazide) and p-toluenesulfonyl hydrazine. Of these, the azo compounds are preferred, with azobisisobutyronitrile being especially preferred.
An appropriate amount of the blowing agent (E) blended is about 0.01 to 50 parts, and especially about 0.5 to 10 parts by weight per 100 parts by weight of the organopolysiloxane (A). Less than 0.01 part by weight of the blowing agent is ineffective for the blowing purpose whereas more than 50 parts by weight of the blowing agent may create large and uneven cells and fail to form a skin layer.
Another organic peroxide (D) may be blended herein insofar as the advantages of the invention are not impaired. Examples of the other organic peroxide are dialkyl organic peroxides and peroxy ester organic peroxides.
Especially in the silicone rubber sponge composition, a dialkyl peroxide and/or peroxy ester is preferably used in combination for the purposes of increasing a blowing magnification and creating more uniform cells. Examples include dicumyl peroxide, 2,5-dimethyl-bis(t-butylperoxyhexane), 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne, t-butylperoxy benzoate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane.
An appropriate amount of the dialkyl peroxide and peroxy ester blended is about 0.1 to 10 parts, and especially about 0.2 to 5 parts by weight per 100 parts by weight of the organopolysiloxane (A).
In the silicone rubber sponge composition, an addition type crosslinking agent may be additionally used for the purposes of creating more uniform cells and improving the compression set of the sponge. Well-known addition type crosslinking agents are useful, and combinations of platinum group catalysts with organohydrogenpolysiloxane having at least two SiH groups in a molecule are often used.
The platinum group catalyst may be any of well-known addition reaction catalysts, for example, metal elements of the platinum group and compounds thereof. Examples include microparticulate platinum metal adsorbed on supports such as silica, alumina and silica gel, platinic chloride, chloroplatinic acid, complexes of chloroplatinic acid hexahydrate with olefins or divinyldimethylpolysiloxane, alcohol solutions of chloroplatinic acid hexahydrate, palladium catalysts, and rhodium catalysts. The catalyst is used in a catalytic amount, and typically in an amount of about 1 to 2,000 ppm, preferably about 10 to 500 ppm of platinum group metal. Less than 1 ppm fail to fully promote crosslinking reaction and result in undercure whereas more than 2,000 ppm affects reactivity little further and is uneconomical.
The organohydrogenpolysiloxane having at least two SiH groups in a molecule may be straight, cyclic or branched. There may be used any of organohydrogenpolysiloxanes well known as the curing agent in addition reaction curing type silicone rubber compositions although an organohydrogenpolysiloxane of the following average compositional formula (5) is often useful.
R4xHySiO(4xe2x88x92xxe2x88x92y)/2xe2x80x83xe2x80x83(5)
Herein R4 is a substituted or unsubstituted monovalent hydrocarbon group as defined for R1, preferably of 1 to 12 carbon atoms, especially 1 to 8 carbon atoms, for example, alkyl, alkenyl, aryl and aralkyl groups, and halogen- and cyano-substituted groups thereof. The letter x is a positive number of from 1 to 2.2, y is a positive number of from 0.002 to 1, and the sum of x+y is from 1.002 to 3. The organohydrogenpolysiloxane has in a molecule at least two, preferably at least three SiH groups, which may be positioned at ends or midway of the molecular chain. Its viscosity is preferably less than about 300 centistokes at 25xc2x0 C. An appropriate amount of organohydrogenpolysiloxane blended is about 0.01 to 10 parts by weight per 100 parts by weight of the organopolysiloxane (A). More preferably the organohydrogenpolysiloxane is added in such amounts that the ratio of silicon atom-bonded hydrogen atoms to alkenyl groups in component (A) may be from 0.5 to 10, especially from 1 to 4. A hydrogen/alkenyl ratio of less than 0.5 may lead to insufficient crosslinking and insufficient mechanical strength whereas a hydrogen/alkenyl ratio of more than 10 may cause deterioration of cured physical properties and especially, substantial losses of heat resistance and compression set.
In the silicone rubber composition and silicone rubber sponge composition according to the invention, flame retardants, fire resistance modifiers, heat resistance modifiers, and coloring agents may be blended, if necessary, as well as dispersants such as alkoxysilanes, carbon functional silanes, and silanol group-bearing low molecular weight siloxanes.
Where the silicone rubber composition is used for the coating of an electrically insulated wire, an adhesion inhibitor and/or heat resistance modifier is preferably blended therein. These additives are customarily used in conventional wire-coating silicone rubber compositions and effective for the purposes of preventing close adhesion to the conductor such as a copper conductor or tin-plated copper conductor and improving the heat resistance, respectively.
Examples of the adhesion inhibitor include paraffins and hydrocarbon resins such as paraffin wax and microcrystalline wax; fatty acids and metal salts thereof such as stearic acid, zinc stearate and calcium stearate; fatty acid amides such as stearamide and methylenebis-stearamide; fatty acid esters such as n-butyl stearate; and ester waxes. Desirably, the adhesion inhibitor is added in an amount of about 0.001 to 5 parts, especially about 0.05 to 1 part by weight per 100 parts by weight of the organopolysiloxane (A). Less than 0.001 part of the adhesion inhibitor may allow the composition to closely bond to the conductor and be ineffective for its purpose. More than 5 parts may sometimes adversely affect the physical properties of rubber.
Examples of the heat resistance modifier include metal oxides such as iron oxide, cerium oxide, zinc oxide, and titanium oxide; cerium silanolate and cerium fatty acid salts. Desirably, the heat resistance modifier is added in an amount of about 0.01 to 5 parts, especially about 0.2 to 3 parts by weight per 100 parts by weight of the organopolysiloxane (A). Less than 0.01 part of the heat resistance modifier may be ineffective for its purpose whereas more than 5 parts may achieve no further improvement in heat resistance.
The composition of the invention may be prepared by uniformly mixing the above essential and optional components in a rubber mixer such as a twin-roll mill, Banbury mixer or dough mixer (kneader), followed by optional heat treatment.
With respect to the molding and vulcanization of the composition, any desired vulcanizing method may be used as long as it can apply a sufficient amount of heat to decompose the curing agent. Suitable molding methods include continuous atmospheric hot air vulcanization in line with extrusion molding, press vulcanization, and injection vulcanization and are not limited thereto. In the practice of the invention, atmospheric hot air vulcanization is advantageously employed. Appropriate conditions therefor include a temperature of about 100 to 500xc2x0 C., especially about 150 to 400xc2x0 C. and a time of about several seconds to 1 hour, especially about 10 seconds to 30 minutes. If necessary, this is followed by secondary vulcanization at about 150 to 250xc2x0 C. for about 1 to 10 hours.
A silicone rubber-covered wire is manufactured by continuously feeding the composition around a wire, typically a copper wire or tin-plated copper wire through an extruder, followed by atmospheric hot air vulcanization in a hot air furnace. If the vulcanization temperature is below 200xc2x0 C., there is a possibility that vulcanization be retarded and micro-voids form. A vulcanization temperature above 550xc2x0 C. may cause over-vulcanization and hence, surface cracks. For this reason, the temperature of the heating furnace is preferably set in the range of about 200 to 550xc2x0 C., especially about 250 to 500xc2x0 C., and the residence time within the furnace is preferably set in the range of about 1 to 300 seconds, especially about 5 to 50 seconds. The hot air vulcanization furnace may be combined with a radiation heating furnace such as a UHF vulcanization furnace or electron beam vulcanization furnace.
There has been described a silicone rubber composition which has a high vulcanization rate and hygienic safety, and can be extrusion vulcanized in a continuous atmospheric hot air vulcanization manner into a cured silicone rubber having satisfactory physical properties without generating voids or surface tack. When the composition is applied to a wire to construct a silicone rubber-covered wire, the coating has improved withstand voltage properties because of the absence of micro-voids and requires no dusting powder because of the eliminated surface tack. The coating allows for smooth cut/stripping required on the processing of wire terminal ends.
Since halogen-free organic peroxides are used, the silicone rubber sponge composition is safe and effectively expandable and can be cured, without a need for a long term of post curing, into a silicone rubber sponge having uniform fine cells and a skin layer with a smooth, tack-free surface.

Silicone rubber composition, silicone rubber sponge composition, and silicone rubber-covered wire