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排序方式: 共有1365条查询结果,搜索用时 15 毫秒
991.
Tsutomu Nakai Takeo Yamashita Tadahiro Ohmi Tadashi Shibata 《Analog Integrated Circuits and Signal Processing》1999,21(2):173-191
Circuit architecture for parallel data processing directly carried out on the hardware have been developed based on a high-functionality transistor, neuron MOSFET (neuMOS or MOS for short). In the MOS data sorting circuit, multiple analog input data are numbered in binary codes according to the order of their magnitudes after a single ramp voltage scan. A MOS motion-vector detector has been developed for on-chip moving image processing based on x- and y-projection data. The circuit can find the movement of an image in two successive frames within a few 100 nsec. The projection-data-based motion detection algorithm has been tested by computer simulation. Test circuits were fabricated by a double-polysilicon CMOS process and basic operation of the circuits has been demonstrated. 相似文献
992.
S Tajima WZ Zhuang MV Kato K Okada Y Ikawa Y Aida 《Canadian Metallurgical Quarterly》1998,243(1):735-746
The mutations of the p53 gene previously represented one of several genetic changes involved in the development of bovine leukemia virus (BLV)-induced lymphosarcoma, while the effects of these mutations on the function of p53 are unknown. We identified four mutations of p53 gene in BLV-infected cattle with lymphosarcoma and demonstrated clearly the existence of two functionally distinct groups of mutants: (i) the mutant forms with substitutions at codons 241 and 242, which were mapped within an evolutionally conserved region and corresponded to the human "hot-spot" mutations, had completely lost the capacities for transactivation and growth suppression and gained transdominant repression activity in p53-null SAOS-2 cells; and (ii) the mutations at codons 206 and 207 were located outside the evolutionally conserved regions. These mutants partially retained the capacity for transactivation and growth suppression and failed to inhibit the transactivation activity of coexpressed wild-type p53, instead showing an enhancement of this activity. In addition, protein analysis using an antibody specific for the mutant form revealed that the mutations at codons 206 and 242 induced a "mutant" conformation of the bovine p53 proteins. Collectively, these results show that mutations of p53 gene in BLV-infected cattle with lymphosarcoma can potentially alter its physiological function and may play an important role in BLV-induced leukemogenesis. 相似文献
993.
This paper describes improvement of the machining characteristics of dry electrical discharge machining (dry EDM) by controlling the discharge gap distance using a piezoelectric actuator. Dry EDM is a new process characterized by small tool electrode wear, negligible damage generated on the machined surface, and significantly high material removal rate especially when oxygen gas is used. However, the narrow discharge gap length compared with conventional EDM using oil as the dielectric working fluid results in frequent occurrence of short circuiting which lowers material removal rate. A piezoelectric actuator with high frequency response was thus introduced to help control gap length of the EDM machine. To elucidate the effects of the piezoelectric actuator, an EDM performance simulator was newly developed to evaluate the machining stability and material removal rate of dry EDM. 相似文献
994.
Photoreduced Graphene Oxide as a Conductive Binder to Improve the Water Splitting Activity of Photocatalyst Sheets
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Zhenhua Pan Takashi Hisatomi Qian Wang Shanshan Chen Akihide Iwase Mamiko Nakabayashi Naoya Shibata Tsuyoshi Takata Masao Katayama Tsutomu Minegishi Akihiko Kudo Kazunari Domen 《Advanced functional materials》2016,26(38):7011-7019
Photocatalyst sheets consisting of H2 evolution photocatalyst (HEP) and O2 evolution photocatalyst (OEP) particles applied to an underlying conductive layer show promise with regard to promoting efficient and scalable water splitting. One of the most important challenges in enhancing the performance of such systems is establishing efficient charge transfer between photocatalyst particles that are often thickly stacked on the conductive layer. In this study, reduced graphene oxide (RGO) is investigated as an additional solid mediator to the conductive layer to bridge particulate photocatalysts and thus ensure effective charge transfer. Photocatalyst sheets made of RhCrOx/LaMg1/3Ta2/3O2N as the HEP and BiVO4:Mo as the OEP are applied to an Au layer together with RGO. The activity of this system is 3.5 times greater following the incorporation of the RGO. Charaterization analyses reveal that RhCrOx/LaMg1/3Ta2/3O2N particles tens of nanometers in size are fixed on larger, micrometer‐sized, BiVO4:Mo particles by RGO photoreduced from GO in situ. The RGO facilitates charge transfer between particles that are distant from the underlying Au layer and thus involves more photocatalyst particles in the water splitting reaction. It is concluded that the incorporation of conductive materials into the photocatalyst particle layer can effectively enhance the water splitting activity of photocatalyst sheets. 相似文献
995.
The paradox of pancytopenia despite cellular bone marrows (BM) was investigated in 120 patients with myelodysplastic syndromes (MDS). Detailed cell cycle kinetics were examined following in vivo infusions of iodo--and/or bromodeoxyuridine (IUdR/BrdU), while the incidence of apoptosis was measured by in situ end labeling (ISEL) of fragmented DNA. Results showed that MDS are highly proliferative disorders with an equally high incidence of apoptotic intramedullary cell death accounting for the paradox of cellularity/cytopenia. By double-labeling BM biopsy sections for ISEL/BrdU we found the peculiar situation of "signal antonymy" where S-phase cells were frequently apoptotic, a phenomenon so far only seen in MDS biopsies. The cause-effect relationship of this excessive proliferation/apoptosis is discussed at length. 相似文献
996.
Amirhossain Chambari Seyed Habib A. Rahmati Amir Abbas Najafi Aida karimi 《Computers & Industrial Engineering》2012
Reliability problems are an important type of optimization problems that are motivated by different needs of real-world applications such as telecommunication systems, transformation systems, and electrical systems, so on. This paper studies a special type of these problems which is called redundancy allocation problem (RAP) and develops a bi-objective RAP (BORAP). The model includes non-repairable series–parallel systems in which the redundancy strategy is considered as a decision variable for individual subsystems. The objective functions of the model are (1) maximizing system reliability and (2) minimizing the system cost. Meanwhile, subject to system-level constraint, the best redundancy strategy among active or cold-standby, component type, and the redundancy level for each subsystem should be determined. To have a more practical model, we have also considered non-constant component hazard functions and imperfect switching of cold-standby redundant component. To solve the model, since RAP belong to the NP-hard class of the optimization problems, two effective multi-objective metaheuristic algorithms named non-dominated sorting genetic algorithms (NSGA-II) and multi-objective particle swarm optimization (MOPSO) are proposed. Finally, the performance of the algorithms is analyzed on a typical case and conclusions are demonstrated. 相似文献
997.
云爆弹是内装高能燃料的高效毁伤弹药,需在特定的高度引爆,才能发挥最大杀伤效能,为此提出了一种适用于低速投放高着速的云爆弹定高引信;该引信系统以FPGA作为主控制器,通过判定GPS提供的高度信息,控制配电器使弹丸在特定高度执行相应的动作,并通过无线传输模块与外部进行通信,接收配置命令或将定高过程产生的数据发送给上位机;针对GPS定位数据更新速率低导致弹丸实际动作高度与目标高度相差大的问题,特提出了一种高度补偿算法,该算法通过在GPS连续两次测定的高度之间插入10个高度判定点,在提高高度信息采样率的同时提升了定高精度;最后用卫星导航信号模拟器对该系统进行了试验测试,结果表明该引信系统定高精度误差不超过1%,系统功耗约为1.5 W,满足实际应用需求。 相似文献
998.
A sample of Citation Classics in three scientific fields was studied to uncover citing motivations. The classics were classified into basic research, methods and reviews. Number of citations received per classic, number of authors, and age of classic per category and scientific field were the parameters studied. Journals and countries accounting for the highest incidence of classics were examined. A striking parallelism was found in the parameters applied to the categories in the scientific fields studied. This parallelism suggests similar citing habits of scientists in the fields studied which should be reflected in the structures of science obtained through citation grounded bibliometric models. 相似文献
999.
Effects of Olive Trees Age on the Minor Components of Oueslati Virgin Olive Oils Produced from Olives Harvested at Different Ripening Degrees
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Fatma Chtourou Enrico Valli Alessandra Bendini Aida Lazzez Tullia Gallina Toschi Mohamed Bouaziz 《Journal of the American Oil Chemists' Society》2017,94(3):435-447
Phenolics, volatiles, squalene, tocopherols, and fatty acids of virgin olive oils (VOO) from adult and young olive trees of the Oueslati variety, typically cultivated in the Center of Tunisia, were analyzed at three different harvesting periods. Significant differences in contents of saturated fatty acids (p < 0.05), squalene (p < 0.05), alpha-tocopherol and total tocopherol (p < 0.02) and oxidized form of decarboxymethyl oleuropein aglycon (p < 0.05) were seen between VOO from adult and young trees during maturation. Moreover, the volatile profiles of VOO from adult and young trees showed significant differences in the amounts of hexanal, 1-penten-3-ol (p < 0.05), (Z)-3-hexenal and (Z)-2-penten-1-ol (p < 0.01). Principal component analysis showed that olives from adult trees should be harvested at the cherry stage of maturation to obtain a satisfactory level of oil quality, while olives from young trees should be harvested at the black maturation stage. 相似文献
1000.
Study on the morphology,static and dynamic mechanical properties of (styrene butadiene rubber/ethylene propylene diene monomer/organoclay) nanocomposites vulcanized by the gamma radiation
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Blends of styrene‐butadiene rubber/ethylene–propylene‐diene monomer (SBR/EPDM) with and without organoclay (OC) were prepared by melt mixing method. Then the samples were vulcanized by gamma radiation in comparison to conventional sulfur curing system. Characterization by X‐ray diffraction analysis, atomic force microscopy, and Field emission scanning electron microscopy revealed the intercalation structure and good dispersion of the OC in prepared nanocomposites. In addition to this, by increasing the absorbed dose of radiation and using OC, reduction in solvent uptake, increase in crosslink density and improvement of mechanical and dynamic–mechanical properties were observed. Comparison of the tensile strength of irradiated nanocomposite with the sulfur cured one's displayed the synergistic effect of the OC and gamma radiation on tensile properties of SBR/EPDM blend. Mooney–Rivlin plot confirmed the increase in crosslink density and interaction between rubbers due to presence of OC and increasing absorbed dose. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43581. 相似文献