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排序方式: 共有1371条查询结果,搜索用时 15 毫秒
951.
Yoshinori Kawase Naoki Omori Masanari Tsujimura 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,61(1):49-55
Mixing time, circulation time and downcomer linear liquid velocity were measured in two sizes of external-loop airlift bioreactors with Newtonian and non-Newtonian fluids. The mixing time increased as a result of an increase of non-Newtonian characteristics. However, the liquid circulation time was affected only slightly by non-Newtonian flow behaviour. A semi-empirical correlation for circulation time in external-loop airlift bioreactors was proposed. The proposed correlation was compared with the present experimental results and those in the literature. Reasonable agreement was obtained between the predicted and experimental values of circulation times. The downcomer liquid velocity was almost independent of the downcomer-to-rise cross-sectional area ratio. The correlation based on the concept of an eddy diffusivity predicted downcomer liquid velocities in Newtonian and non-Newtonian fluids. 相似文献
952.
Information of life is stored in a genome sequence and four nucleotides can be regarded as coding elements and their sequence
as a certain code of life. We study what kinds of code structure the sequences of HIV-1 genes may have. 相似文献
953.
An analytical model is developed to predict the nocturnal thermal performance of a forced-convection type nonselective radiator: its validity is examined by comparison of the predictions with the results of several outdoor experiments. In the experiments, the Reynolds number of a working fluid, which is water in the present study, is varied, while the inlet fluid temperature is kept constant. The presented model predicts time variations in the exit fluid temperature of the radiator accurately. 相似文献
954.
Leptolstatin, a product from Streptomyces sp. SAM1595, is a gap phase-specific inhibitor of the mammalian cell cycle. Physico-chemical properties and spectrometric analyses showed that the structure of leptolstatin is (2Z,6E,8Z,12E,14E,22E)-19,24-dihydro xy-8,10,14,16,18,20,22-heptamethyl-17-oxo-2 , 6,8,12,14,22-tetracosahexaen-5-olide. 相似文献
955.
Nakagawa S.-I. Terane H. Matsumura T. Segawa H. Yoshimoto M. Shinohara H. Kato S.-I. Hatanaka M. Ohira H. Kato Y. Iwatsuki M. Tabuchi K. Horiba Y. 《Solid-State Circuits, IEEE Journal of》1990,25(6):1484-1493
A 50-ns digital image signal processor (DISP)-an image/video application-specific VLSI chip-is discussed. This chip integrates 538 K transistors and dissipates 1.4 W at a 40-MHz clock. It is based on a 24-b fixed-point architecture with a five-stage pipeline. The DISP features a real-time processing capability realized by an enhanced parallel architecture, video-oriented data processing functions, and an instruction cycle time that is typically 35 ns, and 50 ns at worst. This 50-ns cycle time allows the DISP to execute mor than 60-million operations per second (MOPS). High-density 1.0-μm CMOS technology allows numerous on-chip features, including specified resources optimized for image processing. This allows a flexible hardware implementation of various algorithms for picture coding. Several circuit design techniques that are intended to attain a fast instruction cycle are reviewed, including distributed instruction decoding and a hierarchical clocking circuit. The LSI has been designed by the extensive use of a cell-based design method. The processor incorporates a sophisticated testing function compatible with a cell-based design environment 相似文献
956.
Naoki Abe 《New Generation Computing》1997,15(1):3-25
In computational learning theory continuous efforts are made to formulate models of machine learning that are more realistic than previously available models. Two of the most popular models that have been recently proposed, Valiant’s PAC learning model and Angluin’s query learning model, can be thought of as refinements of preceding models such as Gold’s classic paradigm of identification in the limit, in which the question ofhow fast the learning can take place is emphasized. A considerable amount of results have been obtained within these two frameworks, resolving the learnability questions of many important classes of functions and languages. These two particular learning models are by no means comprehensive, and many important aspects of learning are not directly addressed in these models. Aiming towards more realistic theories of learning, many new models and extensions of existing learning models that attempt to formalize such aspects have been developed recently. In this paper, we will review some of these new extensions and models in computational learning theory, concentrating in particular on those proposed and studied by researchers at Theory NEC Laboratory RWCP, and their colleagues at other institutions. 相似文献
957.
N Horiba 《Canadian Metallurgical Quarterly》1997,55(11):2979-2984
Among various diseases of the adrenals, major disorders that cause sexual and gonadal disturbances are congenital adrenal hyperplasia(CAH) and Cushing's syndrome, and the others include virilizing or feminizing adrenocortical tumors. CAH was reviewed based on the recent advances in molecular genetics. The most striking discovery was steroidogenic acute regulatory protein, mutations of which produce lipoid adrenal hyperplasia that was previously attributed to P-450scc deficiency. Reversible amenorrhea or impotence is found in patients with Cushing's syndrome. Low plasma estrogen and testosterone levels are associated with female and male patients, respectively. Elevated adrenal androgen accounts for mild virilization in female patients with ACTH-dependent subtypes. The sites of action at which hypercortisolemia suppresses the hypothalamic-pituitary-gonadal axis were discussed. 相似文献
958.
On the Computational Complexity of Approximating Distributions by Probabilistic Automata 总被引:2,自引:2,他引:0
Machine Learning - We introduce a rigorous performance criterion for training algorithms for probabilistic automata (PAs) and hidden Markov models (HMMs), used extensively for speech recognition,... 相似文献
959.
960.
Takafumi Kanazawa Takao Umegaki Naoki Uchiyama 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1982,32(2):399-406
Dehydration and thermal change in amorphous calcium phosphate (ACP) have been studied by thermogravimetry, differential thermal analysis and X-ray diffractometry. ACP retained water up to about 773 K. Immediately after the dehydration, a high-temperature form of calcium phosphate, α —Ca3(PO4)2 (α -TCP), was obtained by ignition of ACP precipitated from the solution with a high degree of supersaturation. The kinetics of thermal crystallisation of α-TCP from ACP were also studied. 相似文献