检索结果-南通市图书馆

International Journal of Sediment Research 2022年第4期37卷 469-483页

作者： Kazuyuki Ota takahiro sato Ryosuke Arai Meteorology and Fluid Science Division Central Research Institute of Electric Power Industry

The current study proposes a novel framework for the numerical model for estimating the temporal scour considering unsteady sediment inflow and the sediment sorting process. The framework was applied to local scour upstream of a slit weir. The scour model is based on an ordinary nonlinear differential equation derived from sediment continuity and scour rate equations. A one-dimensional(1-D)Boussinesq-type model coupled with nonequilibrium sediment transport was incorporated in the scour model to consider unsteady sediment inflow. In addition, a mixing layer approach was incorporated to determine temporal variations in particle size in the scour hole. The proposed framework was validated using scour experiments conducted under conditions that include non-uniform sediment, live-bed scour,and unsteady flow rate. The simulation results showed satisfactory agreement with experimental results for the scour upstream of a slit weir. The proposed model appropriately explained the hysteresis process for flow unsteadiness, refilling process for live-bed scour, and armoring process for non-uniform sediments. In addition, the model framework proposed in the current study is applicable to local scour around other hydraulic structures(e.g., bridge piers) upon establishing the scour rate equation. Therefore, the current study provides a novel approach for modeling temporal scour that is required to consider unsteady sediment inflow and sediment sorting.

关键词： Local scour Temporal scour Mixing layer theory Slit weir Non-equilibrium bed load

POLYMER COLLOIDS FORMED BY POLYELECTROLYTE COMPLEXATION OF VINYL POLYMERS AND POLYSACCHARIDES IN AQUEOUS SOLUTION

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2013年第1期31卷 39-49页

作者： Hui-dan Liu takahiro sato Department of Macromolecular Science Osaka University

The polyelectrolyte complex formed from the polyanion and polycation was studied by turbidimetry, static and electrophoretic light scattering, and elementary analysis. Sodium salts of polyacrylate （PA） and heparin （Hep） were chosen as the polyanion, and hydrochloric salts of poly（vinyl amine）（PVA） and chitosan （Chts） as the polycation. Although these vinyl polymers and polysaccharides have remarkably different backbone chemical structures and linear charge densities, all the four combinations PA-PVA, PA-Chts, Hep-PVA, and Hep-Chts provide almost stoichiometric polyelectrolyte complexes which are slightly charged owing to the adsorption of the excess polyelectrolyte component onto the neutral complex. The charges stabilize the complex colloids in aqueous solution of a non-stoichiometric mixture, and the aggregation number of the complex colloids increases with approaching to the stoichiometric mixing ratio. The mixing ratio dependence of the aggregation number for the four complexes is explained by the model proposed in the previous study.

关键词： Polyelectrolyte complex Colloidal dispersion Polyacrylate Poly(vinyl amine) Heparin Chitosan Lightscattering.

Spatially adaptive long-term semi-Lagrangian method for accurate velocity advection

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2018年第3期4卷 223-230页

作者： takahiro sato Christopher Batty Takeo Igarashi Ryoichi Ando The University of Tokyo Tokyo Japan University of Waterloo Waterloo Canada. National Institute of Informatics Japan.

We introduce a new advection scheme for fluid *** main contribution is the use of long-term temporal changes in pressure to extend the commonly used semi-Lagrangian scheme further back along the time *** algorithm starts by tracing sample points along a trajectory following the velocity field backwards in time for many *** this backtracing process,the pressure gradient along the path is integrated to correct the velocity of the current time *** show that our method effectively suppresses numerical diffusion,retains small-scale vorticity,and provides better long-term kinetic energy preservation.

关键词：流体动画平流格式轨迹速度场压力梯度

Experimental investigation on cohesionless sandy bank failure resulting from water level rising

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2018年第1期33卷 47-56页

作者： Ryosuke Arai Kazuyuki Ota takahiro sato Yasushi Toyoda Fluid Dynamics Sector Central Research Institute of Electric Power Industry

In the last decade, sediment replenishment forming cohesionless sandy banks below dams has become an increasingly common practice in Japan to compensate for sediment deficits downstream. The erosion process of the placed cohesionless sediment is a combination of lateral toe-erosion and the following mass failure. To explore cohesionless bank failure mechanisms, a series of experiments was done in a soil tank using a compacted sandy soil mass exposed to an increasing water level. Two types of uniform sand(D50= 0.40 mm and 0.17 mm) and two bank heights（50 cm and 25 cm） were used under the condition of a constant bank slope of 75°. The three dimensional（3D） geometry of the bank after failure was measured using a handheld 3D scanner. The motion of bank failure was captured using the particle image velocimetry（PIV） technique, and the matric suction was measured by tensiometers. The compacted sandy soil was eroded by loss of matric suction accompanying the rise in water level which subsequently caused rotational slide and cantilever toppling failure due to destabilization of the bank. The effect of erosion protection resulting from the slumped blocks after these failures is discussed in the light of different failure mechanisms. Tensile strength is analyzed by inverse calculation of cantilever toppling failure events. The tensile strength had non-linear relation with degree of saturation and showed a *** findings of the study show that it is important to incorporate the non-linear relation of tensile strength into stability analysis of cantilever toppling failure and prediction of tension crack depth within unsaturated cohesionless banks.

关键词： Riverbank erosion Matric suction Cohesionless bank Tensile strength

Irrigation system and land use effect on surface water quality in river, at lake Dianchi, Yunnan, China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第6期25卷 1107-1116页

作者： Takashi Tanaka takahiro sato Kazuo Watanabe Ying Wang Dan Yang Hiromo Inoue Kunzhi Li Tatsuya Inamura Graduate School of Agriculture Kyoto University Biotechnology Research Center Kunming University of Science and Technology Crop and Environmental Sciences Division International Rice Research Institute Center for Southeast Asian Studies Kyoto University

The surface water samples were collected in river Dahe and its tributaries, which flow into severely eutrophic lake Dianchi, Yunnan Province, China, in order to elucidate factors controlling water quality fluctuations. The temporal and spatial distribution of water quality tendency was observed. The water quality of each river is dependent on the hydrology effect such water gate and circulating irrigation system. We must consider the hydrology effect to accurately understand water quality variations of river in this study field. In river without highly circulating irrigation system or water gate effect, the downstream nitrate nitrogen （NO3-N） concentration increase occurred in area dominated by open field cultivation, whereas the NO3-N concentration was constant or decreased in area dominated by greenhouse land use. This result suggests that greenhouse covers the soil from precipitation, and nitrate load of greenhouse could be less than that of open field cultivation while the rainfall event. In the upper reaches of river, where is dominated by open field cultivation, there were no sharp increase dissolved molybdate reactive phosphorus and total phosphorus concentration, but P load was accumulated in the lower reaches of river, whose predominant land use is greenhouse. Although the P sources is unclear in this study, greenhouse area may have potential of P loads due to its high P content in greenhouse soil. Considering hydrology effect is necessary to determine what the major factor is influencing the water quality variation, especially in area with highly complicated irrigation system in this studying site.

关键词： lake Dianchi eutrophication surface water quality land use plastic greenhouse circulating irrigation

Clinical differentiation of acute appendicitis and right colonic diverticulitis: A case-control study

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2019年第12期7卷 1393-1402页

作者： Yosuke Sasaki Fumiya Komatsu Naoyasu Kashima takahiro sato Ikutaka Takemoto Sho Kijima Tadashi Maeda Takamasa Ishii Taito Miyazaki Yoshiko Honda Nagato Shimada Yoshihisa Urita Department of General Medicine and Emergency Care Toho University School of Medicine

BACKGROUND Acute right colonic diverticulitis (ARCD) is an important differential diagnosis of acute appendicitis (AA) in Asian countries because of the unusually high prevalence of right colonic diverticula. Due to qualitative improvement and the high penetration rate of computed tomography (CT) scanning in Japan, differentiation of ARCD and AA mainly depends on this modality. But cost, limited availability, and concern for radiation exposure make CT scanning problematic. Differential findings of ARCD from AA are based on several small studies that used univariate comparisons from Korea and Taiwan. Previous studies on clinical and laboratory differences between AA and ARCD are limited. AIM To determine clinical differences between AA and ARCD for differentiation of these two diagnoses by creating a logistic regression model. METHODS We performed an exploratory single-center retrospective case-control study evaluating 369 Japanese patients (age ≥ 16 years), 236 (64.0%) with AA and 133 (36.0%) with ARCD, who were hospitalized between 2012 and 2016. Diagnoses were confirmed by CT images. We compared age, sex, onset-to-visit interval, epigastric/periumbilical pain, right lower quadrant (RLQ) pain, nausea/vomiting, diarrhea, anorexia, medical history, body temperature, blood pressure, heart rate, RLQ tenderness, peritoneal signs, leukocyte count, and levels of serum creatinine, serum C-reactive protein (CRP), and serum alanine aminotrans-ferase. We subsequently performed logistic regression analysis for differentiating AA from ARCD based on the results of the univariate *** In the AA and ARCD groups, median ages were 35.5 and 41.0 years, respectively (p=0.011);median onset-to-visit intervals were 1 [interquartile range (IQR): 0-1] and 2 (IQR: 1-3) days, respectively (P < 0.001);median leukocyte counts were 12600 and 11500/mm3, respectively (P = 0.002);and median CRP levels were 1.1 (IQR: 0.2-4.1) and 4.9 (IQR: 2.9-8.5) mg/dL, respectively (P < 0.001). In th

关键词： Abdominal pain Acute abdomen Appendicitis Clinical difference Creactive protein Diverticulitis Right lower quadrant pain

Window Effect in the Power Spectrum Analysis of a Galaxy Redshift Survey

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Astronomy and Astrophysics 2013年第3期3卷 243-256页

作者： takahiro sato Gert Hutsi Gen Nakamura Kazuhiro Yamamoto Graduate School of Physical Sciences Hiroshima UniversityHigashi-HiroshimaJapan Tartu Observatory TorevereEstonia

We investigate the effect of the window function on the multipole power spectrum in two different ways. First, we consider the convolved power spectrum including the window effect, which is obtained by following the familiar (FKP) method developed by Feldman, Kaiser and Peacock. We show how the convolved multipole power spectrum is related to the original power spectrum, using the multipole moments of the window function. Second, we investigate the deconvolved power spectrum, which is obtained by using the Fourier deconvolution theorem. In the second approach, we measure the multipole power spectrum deconvolved from the window effect. We demonstrate how to deal with the window effect in these two approaches, applying them to the Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) sample.

关键词： Cosmology Large-Scale Structure of Universe

社会责任对公司治理的影响——美国、日本、德国的比较

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

东北大学学报（社会科学版） 2009年第5期11卷 436-442页

作者：佐藤孝弘北京大学法学院北京100871

公司治理主权的理念可以分为股东主权型和利益相关者主权型两种,前者注重股东利益,后者注重利益相关者或社会利益。除交易成本、股份结构的区别之外,影响公司治理的主要因素是社会对公司的期待和公司对社会承担的社会责任。通过对美国... 详细信息

公司治理主权的理念可以分为股东主权型和利益相关者主权型两种,前者注重股东利益,后者注重利益相关者或社会利益。除交易成本、股份结构的区别之外,影响公司治理的主要因素是社会对公司的期待和公司对社会承担的社会责任。通过对美国、日本和德国的公司治理模式和社会责任的比较分析,对产生不同公司治理模式的原因进行了探讨,并对中国的公司治理模式提出了合理的建议。

关键词：公司治理社会责任制度理论

在线全文

学校读者我要写书评

暂无评论

社会责任对德国公司治理的影响

德国研究 2008年第4期23卷 43-46+79页

作者：佐藤孝弘北京大学法学院

美国公司社会责任的概念拥有浓厚的个人主义或自由主义色彩,而它们社会责任的承担方式与股东权的概念紧密相连。德国公司社会责任的一大特点是在追求公司自身利益的同时保护利益相关者的利益并调整其利益关系。而公司的社会责任也根据... 详细信息

美国公司社会责任的概念拥有浓厚的个人主义或自由主义色彩,而它们社会责任的承担方式与股东权的概念紧密相连。德国公司社会责任的一大特点是在追求公司自身利益的同时保护利益相关者的利益并调整其利益关系。而公司的社会责任也根据社会期待而形成,并进一步形成了德国独特的公司治理模式。

关键词：公司治理社会责任德国

Hemodynamic effects of ambrisentan-tadalafil combination therapy on progressive portopulmonary hypertension

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Hepatology 2014年第11期6卷 825-829页

作者： Yu Yamashita Ichizo Tsujino takahiro sato Asuka Yamada Taku Watanabe Hiroshi Ohira Masaharu Nishimura First Department of Medicine Hokkaido University Hospital

Intravenous epoprostenol is recommended for World Health Organization functional class(WHO-FC) Ⅳ patients with pulmonary arterial hypertension(PAH) in the latest guidelines. However, in portopulmonary hypertension(PoP H) patients, advanced liver dysfunction and/or thrombocytopenia often makes the use of intravenous epoprostenol challenging. Here we report the cases of two WHO-FC Ⅳ PoP H patients who were successfully treated with a combination of two oral vasodilators used to treat PAH: ambrisentan and tadalafil. Oral vasodilator therapy using a combination of ambrisentan and tadalafil may be a safe and effective therapeutic option for WHO-FC Ⅳ PoP H patients and should be considered for selected patients with severe and rapidly progressing PoP H.

关键词： Portopulmonary hypertension Ambrisentan Tadalafil Thrombocytopenia