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Spherules isolated from deep sea sediments were analyzed for chemical compositions. Three types of internal texture are observed in Ni-bearing I-type spherules: Ni free Fe oxide mantle with Fe-Ni metallic core, Fe-Ni oxide mantle with Fe-Ni metallic core and Fe-Ni oxide spherules without metallic core. Numerical simulation was performed in order to estimate variation of temperatures and radii of I-type spherules, and the force of inertia exerted on them entering the atmosphere. From the result of the simulation, it is figured out that spherules lose more than 90 percent of their original mass by ablation over 1,900 C and that the force of inertia is maximum at last stage of evaporation. Based on the observations of I-type spherules and the numerical simulation of their formation, we propose a model of the formation process of I-type spherules: during ablation, metallic core is off-centered, then surface of the core is exposed to the air due to the strong force of inertia and oxidation reaction might proceed from the exposed core surface., 資料番号: AA0063352045

With the decrease of device scale and the increase of signal frequency, IR-drop effect becomes a severe problem and influences the measurement circuit performance of MEMS-based micro sensors. IR-drop effect causes the voltage to drop and increases the disturbing noise so as to degrade the SNR and sensitivity of the micro sensor, especially for the capacitive micro sensor. In this paper, the influence of IR-drop effect is analyzed. A new RLC model of classical dual T diode measurement circuit will be presented to describe the wire's parasitism. Experiments based on the silicon capacitive sensor will be demonstrated to support the RLC model and the noise model.

This paper presents a more efficient leading-zeros anticipatory (LZA) for high-performance floating-point computation. The leading zeros anticipation is a critical process to anticipate the number of leading zeros of the addition result in parallel with floating-point addition. However, a potential error by one bit exists in the previous anticipation schemes. In those schemes, some logic was proposed to correct the error after the addition and its leading zeros anticipation, but extra latency was introduced and hence the hardware complexity increased. In our approach, based on a set of production rules, the leading zeros are anticipated exactly, and no correction step is necessary anymore. The production rules are very simple and easy to realize. The latency and logic complexity of the proposed production rules are discussed. Both speed and area advantages are presented.

A logarithmic complexity implementation for the integer comparator is presented. The relation between unsigned integers to be compared and their comparison result is analyzed, and then a logarithmic complexity algorithm is inferred, which takes the advantage of both speed and area. The algorithm is also extended for comparing two signed integers in two's complement. The complexities of the basic algorithm in terms of time and hardware are given. The experimental results of several concrete schemes are also discussed.

A logarithmic complexity implementation for the leading zeros detector is presented. The relation between the leading zeros detection result and the input string to be detected is analyzed, and then the logarithmic complexity algorithm is inferred, which takes the advantage of both speed and area. The complexities of the algorithm in terms of time and hardware are given. The experimental results of several concrete schemes based on the logarithmic complexity algorithm are also discussed.