A 220-MHz pipelined 16-Mb BiCMOS SRAM with PLL proportionalself-timing generator

This 512 Kw×8 b×3 way synchronous BiCMOS SRAM uses a 2-stage wave-pipeline scheme, a PLL self-timing generator and a 0.4-μm BiCMOS process to achieve 220 MHz fully-random read/write operations with a GTL I/O interface. Newly developed circuit technologies include: 1) a zig-zag double word-line scheme, 2) a centered bit-line load layout scheme, and 3) a phase-locked-loop (PLL) with a multistage-tapped ring oscillator which generates a clock cycle proportional pulse (CCPP) and a clock edge lookahead pulse (CELP)     

66/77-kV C-GIS using composite insulation in SF6 gas

A second-generation model of cubicletype gas-insulated switchgear (C-GIS) with composite insulation incorporating SF₆ gas has been developed. The design does not require a gas process in field assembly; it has high reliability and its installation is more rapid; and a further reduction in size is achieved. The design principles are described in detail.     

Development of cable fault location method using fiber optic distributed temperature sensor

When ground-fault problems occur on a cable line, immediate fault location and restoration are required. Therefore, various new methods to locate the fault point instantaneously have been investigated to replace such conventional methods as the Murray loop method and the pulse radar method [1]. These methods require a long time to locate the fault point. One possible fault location method is to sense the temperature rise following a ground fault using a fiber optic distributed temperature sensor. Application of this method was found feasible through sensing the temperature rise at a ground-fault test using a thermocouple as a temperature sensor with test cables [4]. A power/optical composite cable was prepared experimentally and after verifying its thermal mechanical performance, the temperature rise at an incidence of a fault was determined and the anticipated performance was demonstrated in a ground-fault test. This article describes the outline of the test.     

Decoder Initializing Technique for Improving Frame-Erasure Resilience of a CELP Speech Codec

The authors present and evaluate a technique for synchronizing the internal states of a code-excited-linear-prediction (CELP) encoder and decoder after the occurrence of frame erasure. The designed technique, called ldquoduplicated transmission (DT),rdquo uses some redundant information for realizing synchronization. The encoder performs encoding processes twice and sends two codes for each frame. One code is encoded by an encoder that is initialized. The code is used in cases where the previous frame is erased. An onset detector is combined with the DT technique to select the frames to which the DT should be applied. Subjective test results suggest that, by introducing DT selectively, the number of DT frames is reducible by about 80% without degrading the subjective quality. Results demonstrate that synchronization of the internal states is effective in cases of erasure of onset. The DT technique requires no additional algorithmic delay. For that reason, it would a better choice for particular applications for which the delay has a significant impact.     

Effect of 8 MeV electron irradiation on electrical properties of CuInSe2 thin films

Radiation damages due to 8 MeV electron irradiation in electrical properties of CuInSe₂ thin films have been investigated. The n-type CuInSe₂ films in which the carrier concentration was about 3×10¹⁶ cm⁻³, were epitaxially grown on a GaAs(0 0 1) substrate by RF diode sputtering. No significant change in the electrical properties was observed under the electron fluence <3×10¹⁶ e cm⁻². As the electron fluence exceeded 10¹⁷ e cm⁻², both the carrier concentration and Hall mobility slightly decreased. The carrier removal rate was estimated to be about 0.8 cm⁻¹, which is slightly lower than that of III–V compound materials.     

Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (10^{9.3 ± 0.2} colony-forming units mL⁻¹) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10^8.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10^6.8 TBT molecules is adsorbed by a single cell.     

Suppression of photo-induced dilation in cyanide treated hydrogenated amorphous silicon films

Effects of cyanide (CN) treatment with hydrogenated amorphous silicon (a-Si:H) films have been investigated. The decrease of ΔV/V was observed in cyanide treated a-Si:H films and the successive thermal annealing at 200°C after CN treatment induced the further reduction of the ΔV/V. XPS spectra show the indirect evidence that the cyanide species is present within 10 nm from the hydrogenated amorphous silicon surface. The results of CN treatment with a-Si:H solar cells are demonstrated.     

New approach to aortic dissection: development of an insertable aortic prosthesis

We have developed a new aortic prosthesis with which we can replace or reinforce the aorta using a simple percutaneous technique. We have named the new prosthesis the shape-memory aortic prosthesis (SAP); it consists of a spiral-shaped nitinol stent and polyurethane tube. It can be compressed inside a 14F catheter at a low temperature and regain its original shape at above 30 degrees C. As a preliminary study, SAP sutureless grafting into the descending aorta was performed on 10 mongrel dogs. We found that when the proper diameter of SAP was applied, it functioned satisfactorily for 3 months or more. A percutaneous placement technique pertinent to the SAP also was developed and tried on 4 animals. Our procedure was applied to Stanford type B dissection models to close the entry point successfully. This newly developed SAP has potential to be applied to emergency cases of human aortic dissections.