Tech Briefs

Rotating Desk for Collaboration by Two Computer Programmers

Two programmers can work together or alternately with minimal stress. A special-purpose desk has been designed to facilitate collaboration by two computer programmers sharing one desktop computer or computer terminal. The impetus for the design is a trend toward what is known in the software industry as extreme programming — an approach intended to ensure high quality without sacrificing the quantity of computer code produced. Programmers working in pairs is a major feature of extreme programming.

Posted in: Mechanical Components, Briefs

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Ex Vivo Growth of Bioengineered Ligaments and Other Tissues

Lifelike mechanical loads cause cell cultures to grow into lifelike structures.A method of growing bioengineered tissues for use in surgical replacement of damaged anterior cruciate ligaments has been invented. An anterior cruciate ligament is one of two ligaments (the other being the posterior cruciate ligament) that cross in the middle of a knee joint and act to prevent the bones in the knee from sliding forward and backward relative to each other. Anterior cruciate ligaments are frequently torn in sports injuries and traffic accidents, resulting in pain and severe limitations on mobility. By making it possible to grow replacement anterior cruciate ligaments that structurally and functionally resemble natural ones more closely than do totally synthetic replacements, the method could create new opportunities for full or nearly full restoration of functionality in injured knees. The method is also adaptable to the growth of bioengineered replacements for other ligaments (e.g., other knee ligaments as well as those in the hands, wrists, and elbows) and to the production of tissues other than ligaments, including cartilage, bones, muscles, and blood vessels.

Posted in: Medical, Briefs

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Variable-Pressure Washer

Clamping force would be applied in a specified nonuniform pattern. The variable-pressure washer (VPW) is a proposed device that is so named because (1) it would play the role similar to that played by an ordinary washer, except that (2) the clamping pressure applied by it would vary with either circumferential or radial position. In a typical contemplated application, the radially varying clamping pressure would be used to obtain more nearly uniform compression on a pair of concentric seals (e.g., an O-ring or a gasket) in an assembly that experiences larger deformations normal to the sealing surface for locations around the outer diameter of the attachment flange when compared to locations around the inner diameter.

Posted in: Mechanical Components, Briefs

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Apparatus for Precise Indium-Bump Bonding of Microchips

Bonding force is distributed more nearly evenly and controlled more precisely. An improved apparatus has been designed and built for use in precise positioning and pressing of a microchip onto a substrate (which could, optionally, be another microchip) for the purpose of indium-bump bonding. The apparatus (see figure) includes the following:  

Posted in: Semiconductors & ICs, Briefs, TSP

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Multiple Embedded Processors for Fault-Tolerant Computing

Outputs of processors would be compared to detect and correct bit errors.A fault-tolerant computer architecture has been conceived in an effort to reduce vulnerability to single-event upsets (spurious bit flips caused by impingement of energetic ionizing particles or photons). As in some prior fault-tolerant architectures, the redundancy needed for fault tolerance is obtained by use of multiple processors in one computer. Unlike prior architectures, the multiple processors are embedded in a single field-programmable gate array (FPGA). What makes this new approach practical is the recent commercial availability of FPGAs that are capable of having multiple embedded processors.

Posted in: Semiconductors & ICs, Briefs, TSP

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Flexible, Carbon-Based Ohmic Contacts for Organic Transistors

These contacts are printed using an inexpensive, low temperature process. A low-temperature process for fabricating flexible, ohmic contacts for use in organic thin-film transistors (OTFTs) has been developed. Typical drainsource contact materials used previously for OTFTs include (1) vacuum deposited noble metal contacts and (2) solution deposited intrinsically conducting molecular or polymeric contacts. Both of these approaches, however, have serious drawbacks.

Posted in: Semiconductors & ICs, Briefs, TSP

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N-Type d Doping of High-Purity Silicon Imaging Arrays

Success depends on details of a low-temperature MBE process. A process for n-type (electron-donor) delta (d) doping has shown promise as a means of modifying back-illuminated image detectors made from n-doped high-purity silicon to enable them to detect high-energy photons (ultraviolet and x-rays) and low-energy charged particles (electrons and ions). This process is applicable to imaging detectors of several types, including charge-coupled devices, hybrid devices, and complementary metal oxide/semiconductor detector arrays.

Posted in: Semiconductors & ICs, Briefs, TSP

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