Radiation damage of bipolar SST due to γ rays of Co

In order to investigate radiation hardness of the bipolar SST transistors, transistor samples were exposed to gamma rays from an intense ⁶⁰Co source. The transistor samples were hard up to a total dose of the order of 10⁴ Gy.     

A Multipitch Analyzer Based on Harmonic Temporal Structured Clustering

This paper proposes a multipitch analyzer called the harmonic temporal structured clustering (HTC) method, that jointly estimates pitch, intensity, onset, duration, etc., of each underlying source in a multipitch audio signal. HTC decomposes the energy patterns diffused in time-frequency space, i.e., the power spectrum time series, into distinct clusters such that each has originated from a single source. The problem is equivalent to approximating the observed power spectrum time series by superimposed HTC source models, whose parameters are associated with the acoustic features that we wish to extract. The update equations of the HTC are explicitly derived by formulating the HTC source model with a Gaussian kernel representation. We verified through experiments the potential of the HTC method     

Intelligential industrial management

In this paper, we propose the intelligential industrial management which is the new concept in the industrial management. In the intelligential industrial management, the know-how and experience in the production process are divided into the fact, relation, and action in whit many criteria are used. The rule is constructed from the relation and action. And the inference process shows the sequence of the action and rule by using the inference symbol proposed.     

Intentional side etching to achieve low-noise GaAs f.e.t.

A very-low-noise 0.5 ?m-gate GaAs f.e.t. is realised by using intentional side etching of an Au/Ti double layer as the Schottky-gate metal. At 12 GHz, the minimum noise figure is 2.1 dB, with 7.6 dB associated gain at a bias of VD = 4 V, ID= 10 mA. Maximum stable gain is 14 dB at VD = 4 V, ID = 30 mA.     

Generating material strength standards of aluminum alloys for research reactors I. Yield strength values Sy and tensile strength values Su

Aluminum alloys are frequently used as structural materials for research reactors. The material strength standards, however, such as the yield strength values (S_y), the tensile strength values (S_u) and the design fatigue curve—which are needed to use aluminum alloys as structural materials in “design by analysis”—for those materials have not been determined yet. Hence, a series of material tests was performed and the results were statistically analyzed with the aim of generating these material strength standards. This paper, the first in a series on material strength standards of aluminum alloys, describes the aspects of the tensile properties of the standards. The draft standards were compared with MITI no. 501 as well as with the ASME codes, and the trend of the available data also was examined. It was revealed that the draft proposal could be adopted as the material strength standards, and that the values of the draft standards at and above 150°C for A6061-T6 and A6063-T6 could be applied only to the reactor operating conditions III and IV. Also the draft standards have already been adopted in the Science and Technology Agency regulatory guide (standards for structural design of nuclear research plants).     

Fluctuation phenomena below the superconducting transition

The fluctuation propagator for the superconducting order parameter belowT _c is derived for a gapless superconductor. The fluctuation of the order parameter consists of two distinct modes: the fluctuations of the phase and the modulus of the order parameter. The former fluctuation obeys a phononlike dispersion, while the latter fluctuation is described by a damping diffusion type equation. The present theory gives an account of the fluctuation-induced Josephson effect belowT _c observed recently by Carlson and Goldman.     

Surface passivation of the thin‐film LAPS with perhydropolysilazane‐derived silica treated by O2 plasma

Here, we describe a novel method for surface passivation of the thin‐film light addressable potentiometric sensor (LAPS). To form a uniform passivation layer, perhydropolysilazane (PHPS) was utilized as a spin‐coatable precursor of silica. After transformation of PHPS into silica by baking, we introduced an O₂ plasma treatment aiming for enhancement of the water resistance of the PHPS‐derived silica (PDS) film by completing the PHPS‐to‐silica conversion. To confirm the effect of the O₂ plasma treatment, the PDS film was deposited on a thin‐film LAPS electrode and tested by immersion in a cell culturing medium. The immersion test demonstrated that the plasma‐treated PDS film could keep the electrode stable longer than the untreated could. With the treated PSD film of 600 nm in thickness, a lifetime of the thin‐film LAPS was estimated at over 2 weeks, which is sufficient for cell culturing experiments. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Cost reduction of polycrystalline diamond compact bits through improved durability

This work reports the results of laboratory drilling tests conducted in order to measure improvements due to design and cutter modifications on PDC bits intended for use in geothermal well drilling. These tests, using 142.88 mm-dia. PDC full face bits, concentrated on improvements in bit life and cost performance. The tests were performed using granite drilling samples and a laboratory drilling machine at atmospheric conditions. The results from changes in bit and cutter shape are reported in the work.