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排序方式: 共有1090条查询结果,搜索用时 31 毫秒
111.
Y Abe S Umemura K Sugimoto N Hirawa Y Kato N Yokoyama T Yokoyama J Iwai M Ishii 《Canadian Metallurgical Quarterly》1995,8(1):74-79
A method of reducing the amount of data required to reconstruct an image is described. In this scheme, fully sampled low spatial frequency data are acquired up to a given cutoff frequency and above this point, only alternate lines are sampled. Two images are produced, one of low definition and one of high definition but aliased. The proposed algorithm unwraps the aliased data, which are then used to enhance the low pass image, yielding a best estimate of the true image. The reduced sampling technique is shown to afford biological images that are almost indistinguishable from those obtained from a complete data set. 相似文献
112.
The characteristics of control system design using a universal learning network (ULN) are such that both the controlled systems
and their controller are represented in a unified framework, and that the learning stage of the ULN can be executed by using
not only first-order derivatives (gradient) but also the higher order derivatives of the criterion function with respect to
parameters. ULNs have the same generalization ability as neural networks. So the ULN controller is able to control the system
in a favorable way under an environment which is little different from the environment of the control system at the learning
stage. However, stability cannot be sufficiently realized. In this paper, we propose a robust control method using a ULN and
second-order derivatives of that ULN. Robust control, as considered here, is defined as follows. Even though the initial values
of the node outputs are very different from those at the learning stage, the control system is able to reduce its influence
to other node outputs and can control the system as in the case of no variation. In order to realize such robust control,
a new term concerning the variation is added to the usual criterion function, and the parameters are adjusted so as to minimize
the above-mentioned criterion function using second-order derivatives of the criterion function with respect to the parameters.
Finally, it is shown that the ULN controller constructed by the proposed method works effectively in a simulation study of
a non-linear crane system.
This work was presented, in part, at the International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20,
1996 相似文献
113.
This paper demonstrates the low-voltage and low-power operation of a MOS sample-and-hold circuit while preserving speed and accuracy, aiming at the realization of a pipelined low-voltage and low-power analog-to-digital converter on a system large-scale integrated circuit. It was fabricated by utilizing 0.35-/spl mu/m CMOS technology. The main feature of this circuit is that all the input, signals, and output are in the current form. The circuit consists of simple current mirrors. In order to eliminate the signal-dependent current transfer ratio error, voltages at the drain terminals of mirror transistors are fixed as constant. A source degeneration resistor, which is a transistor in the triode operational region, is connected to a mirror transistor in order to alleviate the influence of the threshold and transconductance parameter variations. Control signals are boosted in voltage and applied to the gate of switch NMOS transistors in the signal path in order to reduce the on-resistance of analog switches. A differential configuration is adopted throughout the entire circuit and effectively cancels switch feedthrough errors. As a result, a 30-MS/s operation with a signal-to-noise ratio (SNR) of 56 dB from a 1-V supply has been achieved, when the input current is /spl plusmn/200 /spl mu/A. The chip even operated down to 0.85 V with a 20-MHz clock. The SNR was measured as 50 dB with an input current of /spl plusmn/100 /spl mu/A. 相似文献
114.
Effective acid sites for the dehydration of 2-propanol and isomerization of 1-butene were found to be generated by glass formation of calcium metaphosphate. The number of these sites with strong acidity remarkably decreased by the crystallization of the glass, where the condensation of hydroxyl groups were significant. Thus, the sites must be the monohydrogen phosphate protons. 相似文献
115.
The inhibitory effects of a potent nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), on 2-deoxy-D-glucose (2-DG)-induced hyperglycemia were investigated in rats. L-NAME significantly inhibited 2-DG-induced hyperglycemia, although N(G)-nitro-D-arginine methyl ester (D-NAME) did not affect it. A similar NO synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), also inhibited 2-DG-induced hyperglycemia. The antagonistic effects of L-NAME are unrelated to the cholinergic system, since the muscarinic receptor antagonist scopolamine did not affect 2-DG-induced hyperglycemia. The neuronal NO synthase inhibitor 7-nitroindazole (7-NI) did not reduce 2-DG-induced hyperglycemia, but rather enhanced it. Our results suggest that NO may be involved in glucose homeostasis and that the inhibitory effects of L-NAME on 2-DG-induced hyperglycemia are not related to muscarinic receptors or neuronal NO synthase. 相似文献
116.
Resistivity measurements on the hydrogenation disproportionation desorption recombination (HDDR) phenomena in near stoichiometric Nd---Fe---B alloys were carried out in the temperature range of T=740–900 °C in order to investigate the effect of additional elements such as Co, Ga and Zr. These studies were combined with detailed temperature-pressure-analysis to relate the observed changes in resistivity with the solubility of hydrogen in the rare-earth metal. Higher relative resistivity changes can be observed when lower disproportionation temperatures are applied. This tendency depends on the amount of hydrogen absorbed in the disproportionated mixture. The addition of Co leads to a longer completion time of the disproportionation reaction. In particular, the alloy with both Co and Ga additions exhibits the longest completion time. These observations suggest that Co stabilises the 2-14-1 phase and Ga addition enhances this effect. These additional elements decrease the number of hydrogen atoms absorbed per formula unit and also increase the onset hydrogen pressure of the disproportionation and recombination reactions. On desorption, Co and Ga additions decrease the activation energy of the recombination reaction and lead to a higher reaction rate of these alloys compared to that of the ternary alloy, which is especially pronounced during the initial stages of recombination and which may be relevant for the development of anisotropic features in the recombined state. 相似文献
117.
Tsugaru K. Sugimoto Y. Noda M. Ito T. Suwa Y. 《Solid-State Circuits, IEEE Journal of》1990,25(3):653-659
A +5-V single-power-supply 10-b video BiCMOS sample-and-hold IC is described. Video speed, low power, and 10-b accuracy sample-and-hold operation have been achieved using a complementary connected buffer format sample switch. A high-speed p-n-p transistor used in the sample switch is formed by a combination of n-p-n and PMOS transistors. The sample-and-hold operation is accomplished by feeding back the hold capacitor voltage to the sample switch inputs, so that the inputs transfer symmetrically for the hold capacitor voltage at any input level. The sample-and-hold IC has been implemented in 1.2-μm BiCMOS technology and evaluated. The following results have been obtained: 185-MHz 3-dB bandwidth at 22-pF hold capacitor, 63-dB signal-to-noise ratio at 8-MHz full-scale input, 20-ns acquisition time at 1-V step input, 15-ns switch setting time, and 0.1% linearity error. Power dissipation is 150 mW 相似文献
118.
Solar Cells: High Efficiency Cu2ZnSn(S,Se)4 Solar Cells by Applying a Double In2S3/CdS Emitter (Adv. Mater. 44/2014) 下载免费PDF全文
119.
Cassidy R. Sugimoto 《Scientometrics》2011,86(2):449-461
Disciplines vary in the types of communicative genres they use to disseminate knowledge and citing patterns used within these genres. However, citation analyses have predominately relied on the references and citations of one type of communicative genre. It is argued that this is particularly problematic for studies of interdisciplinarity, where analyses bias the disciplines that communicate using the genre under investigation. This may lead to inaccurate or incomplete results in terms of fully understanding the interrelationships between disciplines. This study analyzes a set of 15,870 references from 97 LIS dissertations, in order to demonstrate the difference in discipline and author rankings, based on the genre under investigation. This work encourages future work that takes into account multiple citing and cited works, especially where indicators of interdisciplinarity are used for the allocation of resources or ranking of scholars. 相似文献
120.
Ozasa K Shimizu Y Sakata R Sugiyama H Grant EJ Soda M Kasagi F Suyama A 《Radiation protection dosimetry》2011,146(1-3):272-275
Late health effects of exposure to atomic bomb radiation have been evaluated in survivors. A cohort of 120 321 people has been followed since 1950 for mortality, including the cause of death using the Japanese population registry system (Life Span Study), and for cancer incidence using population-based cancer registries. Findings have included a markedly increased risk of leukaemia several years after the exposure, increased risk of various malignant tumours several decades after the exposure and, more recently, findings of increased rates of non-cancer diseases such as cardiovascular diseases. 相似文献