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排序方式: 共有336条查询结果,搜索用时 15 毫秒
21.
Masanori Katagiri Shigeyuki Izumi Jun’ya Hori Yoshiko Fujii Keisaku Hatanaka 《Journal of Low Temperature Physics》2007,148(3-4):127-132
The heat transfer properties of 3He bubbles in the nucleate boiling state have been investigated in liquid 3He below 1.0 K by using the shadowgraph method. The temperature difference between the copper surface and liquid 3He temperature was also measured as a function of heat flux in steady state. The size and number of bubbles departing from
the surface in a specific time were compared using photograph recorded by a high-speed video camera at various heat flux and
liquid 3He temperature of 0.5, 0.7 and 1.0 K. 相似文献
22.
A multi-spectral non-local (MSN) method is developed for advanced retrieval of boundary layer cloud properties from remote sensing data, as an alternative to the independent pixel approximation (IPA) method. The non-local method uses data at both the target pixel and neighboring pixels to retrieve cloud properties such as pixel-averaged cloud optical thickness and effective droplet radius. Radiance data to be observed from space were simulated by a three-dimensional (3D) radiation model and a stochastic boundary layer cloud model with two-dimensional (horizontal and vertical) variability in cloud liquid water and effective radius. An adiabatic assumption is used for each cloud column to model the geometrical thickness and vertical profiles of cloud liquid water content and effective droplet radius, neglecting drizzle and cloud brokenness for simplicity. The dependence of radiative smoothing and roughening on horizontal scale, optical thickness and single scattering albedo are investigated. Then, retrieval methods using 250-m horizontal resolution data onboard new generation satellites are discussed. The regression model for the MSN method was trained based on datasets from numerical simulations. The training was performed with respect to various domain averages of optical thickness and effective radius, because smoothing and roughening effects are strongly dependent on the two variables. Retrieval accuracy is discussed here with datasets independent of those used in the training, towards assessing the generality of the technique. It is demonstrated that retrieval accuracy of cloud optical thickness, which is often retrieved from single-spectral visible-wavelength data, is improved the most using neighboring pixel data and secondly using multi-spectral data, and ideally with both. When the IPA retrieval method is applied to optical thickness and effective radius, the root-mean-square relative errors can be 15-90%, depending on solar and view directions. In contrast, the MSN method has errors of 4-10%, which is smaller than IPA by a factor of 2-10. It is also suggested that the accuracy of the MSN method is insensitive to some assumptions in the inhomogeneous cloud input data used to train the regression model. 相似文献
23.
This paper considers time-varying uncertain constrained systems, and develops a method for computing a probabilistic output admissible (POA) set. This set consists of the initial states probabilistically assured to satisfy the constraint. The time-invariant counterpart has already been investigated in Hatanaka and Takaba [Computations of probabilistic output admissible set for uncertain constrained systems, Automatica 44 (2) (2008), to appear]. We first define the POA set for time-varying uncertainties with finite dimensional probability space. Then, we show that an algorithm similar to Hatanaka and Takaba [Computations of probabilistic output admissible set for uncertain constrained systems, Automatica 44 (2) (2008), to appear] provides the POA set also in the time-varying case, as long as an upper bound of a what we call future output admissibility (FOA) index is available. We moreover present two methods for computing the upper bound of the FOA index: probabilistic and deterministic methods. A numerical simulation demonstrates the effectiveness of our algorithm. 相似文献
24.
Arima J Uesugi Y Iwabuchi M Hatanaka T 《Protein engineering, design & selection : PEDS》2008,21(1):45-53
We purified and characterized the aminopeptidase P from Streptomyces costaricanus TH-4 (thAPP). This enzyme has a tetramer structure, a metal-ion preference toward Zn, broad substrate specificity and a narrow pH dependency for activity. The primary structure of thAPP, respectively, exhibits 91% and 65% identity with those of two other APPs-APP I and APP II-from Streptomyces lividans (slAPP I and slAPP II). We next overexpressed the genes encoding thAPP and slAPP II in Escherichia coli and characterized them. Two differences were apparent in their properties: slAPP II formed a dimer, whereas thAPP formed a tetramer; also, the alkaline side pKa for the catalytic action of slAPP II is higher than that of thAPP. Investigation using chimeras of both enzymes revealed that the N-terminal domain is associated with the determination of pKa values for catalytic action and quaternary structure. 相似文献
25.
Ohba A. Ohbayashi S. Shiomi T. Takano S. Anami K. Honda H. Ishigaki Y. Hatanaka M. Nagao S. Kayano S. 《Solid-State Circuits, IEEE Journal of》1991,26(4):507-512
A 7-Mb BiCMOS ECL (emitter coupled logic) SRAM was fabricated in a 0.8 μm BiCMOS process. An improved buffer with a high-level output of nearly V CC is adopted to eliminate the DC current in the level converter circuit, and the PMOS transistor has a wide operating margin in the level converter. The configurable bit organization is realized by using a sense-amplifier switch circuit with no access degradation. A wired-OR demultiplexer for the ×1 output, having the same critical path as the ×4 output circuit, allows for the same access time between the two modes. The ×1 or ×4 mode is electrically selected by the external signal. A simplified programming redundancy technology, shift redundancy, is utilized. Address programming is performed by cutting only one fuse in the shift redundancy. The RAM operates at the ECL-10K level with an access time of 7 ns. and the power dissipation at 50 MHz is 600 mW for the × mode 相似文献
26.
Hiroyuki Hamada Hiroyuki Kato Naoto Ito Yoshihiko Takase Hironobu Nanbu Shoko Mishima Hiromu Sakaki Kiyotaka Sato 《European Journal of Lipid Science and Technology》2010,112(12):1323-1330
Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures. 相似文献
27.
M.A. Dar S.G. Ansari Z.A. Ansari Hironobu Umemoto Young-Soon Kim Hyung-Kee Seo Gil-Sung Kim Eun-Kyung Suh Hyung-Shik Shin 《International Journal of Refractory Metals and Hard Materials》2006,24(6):418-426
Diamond thin films have been deposited using hot filament chemical vapour deposition technique on manually scratched p-Si(1 0 0) substrate, with and without magnesium interlayer. In spite of magnesium melting point being lower (Tm = 649 °C) than the growth temperature of the substrate (Ts 750 °C) used in these experiments, it was found that high quality diamond films could be grown on Mg covered substrate. A liquid substrate is probably generated during the diamond film growth. Raman spectroscopy analysis exhibited only the triply degenerate, zone centre optical phonon peak at 1333 cm−1 indicating that nearly stress free crystallites were present. Broadening of the Raman peak (11.76 cm−1) indicates that some small crystallites also are present. Scanning electron and atomic force microscopy accompanied by X-ray diffraction analysis where used to compare the details of diamond film growth directly on scratched Si(1 0 0) and Mg interlayered scratched Si(1 0 0) substrates. 相似文献
28.
The future prospect of remote Cat-CVD, in which the decomposition and the deposition chambers are separated, is discussed on the basis of the absolute density measurements of H atoms. It is now well recognized that uniform deposition is possible on a large area without plasma damages by Cat-CVD. However, we may not overlook the demerits in Cat-CVD. One of the demerits is the poisoning of the catalyzer surfaces by the material gases, both temporary and permanent. One technique to overcome this problem is remote Cat-CVD. The question is how to separate the decomposition and deposition areas. If the separation is not enough, there should be back diffusion of the material gases, which will poison the catalyzers. If the separation is too tight, radicals may not effuse out from the decomposition chamber. These problems are discussed and it is shown that SiO2 coating to reduce the radical recombination rates on walls is promising. The possibility of the polytetrafluoroethene coating by Cat-CVD is also discussed. 相似文献
29.
Shigemitsu Hatanaka Eisuke Sakamoto Naoki Mishima Akio Muramatsu 《Materials and Structures》2008,41(7):1235-1249
The strength and hardness of concrete slab surface is considered significantly affected by bleeding of concrete. It has been
reported that dewatering by vacuum processing is quite effective to obtain high density of concrete. The method, however,
has not been successfully used for the concrete work in the field of building construction, compared with that of civil engineering
works in Japan. In the present study, firstly the state of the art concerning vacuum dewatering method is reviewed and the
newly improved vacuum dewatering method is introduced. Then the effect of the proposed method on concrete properties of slab
is examined by a series of experiments in order to find more reasonable and effective way in the application of the proposed
method. 相似文献
30.
In this study, a condensation heat transfer experiment on vertical continuous and dispersed finned surfaces using FC5312 was carried out. Experimental parameters were the pitch and height of the fin, and the dispersed fin length. In the results, the phenomena of condensate retention were observed in the bottom of each row of the dispersed fin. The condensate flow from the upper row was concentrated into the valley of the fin and then flowed down into the valley of the next fin. Moreover, it was found from the experiment that the heat transfer coefficient on the dispersed finned surface was lower than the one on the continuous finned surface as the fin pitch was smaller, but was larger than that of the continued finned surface for a larger fin pitch. Furthermore, the heat transfer enhancing effect became more significant for the higher fin with the larger fin pitch, and the heat transfer reducing effect became more significant for the lower fin with the smaller fin pitch. These special characteristics of condensation mentioned above were caused by the phenomena of condensate retention in each row of the fin and the flow pattern of the condensate between two adjacent fins on the dispersed finned surface based on experimental observations. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20221 相似文献