检索结果-南通市图书馆

Evolution of downsized crescent-shaped dune in wind tunnel experiment

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第1期57卷 143-151页

作者： ZHANG Yang wang yuan JIA Pan Department of Fluid Machinery and Engineering Xi’an Jiaotong University

The migration of a downsized crescent-shaped dune was investigated in a wind tunnel *** upwind influx and vertical oscillation of the sand bed were introduced to modulate the saturation level of the sand flux above the dune surface to affect dune *** evolution was recorded by top-view photography and then abstracted as the evolution of self-defined characteristic quantities using a digital image processing *** results showed that,in contrast to the case for spanwise quantities,the evolution of streamwise quantities corresponds to a linear increase in the modulation magnitude more positively and in a monotonic and convergent *** contrast with quantities on the windward face,the changes in quantities with respect to the horns were nonmonotonic with time and almost uncorrelated with the variation in modulation strength,which reveals the distinctiveness of leeside evolution.

关键词： crescent-shaped dune wind tunnel experiment saturation level of sand flux digital image processing dune evolution

Impacts of inter-sectoral trade on carbon emissions --a case of China in 2007

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2012年第3期6卷 387-402页

作者： Xiuqi FANG Benyong WEI yuan wang School of Geography Beijing Normal UniversityBeijing 100875China Institute of Geology China Earthquake AdministrationBeijing 100029China School of Environment Science and Technology Tianjin UniversityTianjin 300072China

With the increase in international trade, more attention has been given to quantifying the impacts of international trade on energy use and carbon emissions. Input-output analysis is a suitable tool for assessing resources or pollutants embodied in trade and it has become a critical tool for performing such analysis. This study estimated the national and sectoral carbon emissions embodied in Chinese international trade using the latest available China input-output table of 2007. The results showed that a significant exporting behavior of embodied carbon emissions existed in China＇s trade. Over 1/3 of the emissions in Chinese domestic production processes were generated for exports in 2007. The net balance of emissions embodied in exports and imports accounted for nearly 30% of China＇s domestic emissions, which means that any policy made to increase the exports would result in a significant growth of China＇s domestic emissions. Since over half of China＇s export trade is processing trade, the re-exported emissions could not be overlooked; otherwise, it would hard to capture the actual emissions generated abroad to obtain China＇s domestic consumption. The enlargement of export scale is a primary driven factor to the rapid growth of China＇s exported emissions. It is necessary for China to adjust its economic and industrial structure to reduce the dependence of economic growth on the export trade. However, when adjusting industry structures or making policies on carbon emission reduction, it will be more reasonable to consider the relationship between production and consumption, rather than just focus on the emission values of sectors＇ direct production, as a large part of carbon emissions emitted by the principal direct polluters were generated to obtain the products which were required by other sectors.

关键词： international trade carbon emissions input-output analysis China

shinySRT: shareable and interactive visualization of spatially resolveddata

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

Journal of Genetics and Genomics 2024年第10期51卷 1147-1150页

作者： Zhenzhong Pan Ran Zhou yuan wang Department of Neurosurgery and State Key Laboratory of Biotherapy and Cancer Center West China HospitalSichuan UniversityChengduSichuan 610041China

A plethora of spatially resolved transcriptomics(SRT)technologies have emerged recently,with the objective of uncovering molecular variations in disease pathology(Ren et al.,2023),tissue homeostasis,and developmental ... 详细信息

关键词： homeostasis spatially

Medicinal plant activity on Helicobacter pylori related diseases

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第30期20卷 10368-10382页

作者： yuan-Chuen wang Department of Food Science and Biotechnology National Chung Hsing University

More than 50% of the world population is infected with Helicobacter pylori (H. pylori). The bacterium highly links to peptic ulcer diseases and duodenal ulcer, which was classified as a group I carcinogen in 1994 by the WHO. The pathogenesis of H. pylori is contributed by its virulence factors including urease, flagella, vacuolating cytotoxin A (VacA), cytotoxin-associated gene antigen (Cag A), and others. Of those virulence factors, VacA and CagA play the key roles. Infection with H. pylori vacA-positive strains can lead to vacuolation and apoptosis, whereas infection with cagA-positive strains might result in severe gastric inflammation and gastric cancer. Numerous medicinal plants have been reported for their anti-H. pylori activity, and the relevant active compounds including polyphenols, flavonoids, quinones, coumarins, terpenoids, and alkaloids have been studied. The anti-H. pylori action mechanisms, including inhibition of enzymatic (urease, DNA gyrase, dihydrofolate reductase, N-acetyltransferase, and myeloperoxidase) and adhesive activities, high redox potential, and hydrophilic/hydrophobic natures of compounds, have also been discussed in detail. H. pylori-induced gastric inflammation may progress to superficial gastritis, atrophic gastritis, and finally gastric cancer. Many natural products have anti-H. pylori-induced inflammation activity and the relevant mechanisms include suppression of nuclear factor-κB and mitogen-activated protein kinase pathway activation and inhibition of oxidative stress. Anti-H. pylori induced gastric inflammatory effects of plant products, including quercetin, apigenin, carotenoids-rich algae, tea product, garlic extract, apple peel polyphenol, and finger-root extract, have been documented. In conclusion, many medicinal plant products possess anti-H. pylori activity as well as an anti-H. pylori-induced gastric inflammatory effect. Those plant products have showed great potential as pharmaceutical candida

关键词： Helicobacter pylori Virulence factor Medicinal plant Active compound Mechanism Inflammation Gastric cancer nuclear factor-kappa B pathway

Conodont Biostratigraphic Constraint on the Lower Taiyuan Formation in Southern North China and Its Paleogeographic Implications

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

Journal of Earth Science 2022年第6期33卷 1480-1493页

作者： yuan wang Jianghai Yang Dong-Xun yuan Jia Liu Rui Ma School of Earth Sciences China University of GeosciencesWuhan430074China State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan430074China School of Resources and Geosciences China University of Mining and TechnologyXuzhou221116China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing210008China

The Late Paleozoic Taiyuan Formation in North China is mainly composed of a mixed shallow-marine carbonate and terrigenous clastic *** basal limestones have been constrained in the late Pennsylvanian to Early *** further constrain the age of the lowest Taiyuan Formation,we obtained two genera and 16 species of conodonts from the bottom limestones of the Taiyuan Formation in two sections in Henan Province,southern North *** fauna includes Idiognathodus hebeiensis,Streptognathodus isolatus,***,***,***,***,***,***,***,***,***,***,***,***,***,and ***.A genus of Streptognathodus dominated conodont assemblage with some Idiognathodus *** indicates a late Gzhelian(latest Pennsylvanian)age for the lowest Taiyuan Formation in southern North *** is consistent with recently published high-precision zircon U-Pb ages from ash *** on conodont biostratigraphy,the basal limestones of the Taiyuan Formation in Henan Province(southern North China)can be correlated with the upper part of Miaogou limestones of the Taiyuan Formation in Shanxi Province(northern North China).This correlation might reflect a significant sea-level rise in North China,possibly corresponding to a deglaciation event at the Permo-Carboniferous transition.

关键词： Taiyuan Formation conodonts Gzhelian southern North China biostratigraphy

Dynamic event-triggered finite-time control for multiple Euler-Lagrange systems using integral terminal sliding mode

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第11期66卷 3164-3173页

作者： wang Yan LI Xiao-Meng yuan wang YAO DeYin LI HongYi Information Technology Research Institute Shenzhen Institute of Information TechnologyShenzhen 518172China School of Automation Guangdong University of TechnologyGuangzhou 510006China

The tracking control for multiple Euler-Lagrange systems with external disturbances in finite time under undirected topology is investigated in this paper.A dynamic model is established for the multi-EL systems to accurately describe the general mechanical ***,an integral terminal sliding mode surface is devised to converge the tracking errors of the system state to a neighborhood of zero within finite time,and the designed finite-time controller ensures fast convergence and high steady-state *** reduce the controller update frequency and network transmission communication load,a dynamic event-triggered mechanism is introduced between the sensor and controller,and no Zeno behavior was ***,the Lyapunov stability theory and finite-time stability criterion prove that all signals in the closed-loop system are uniformly ultimately bounded in finite ***,the simulation results verified the effectiveness of the proposed control method.

关键词： dynamic event-triggered mechanism external disturbances finite-time control integral terminal sliding mode control multiple Euler–Lagrange systems

Automated Testing of Web Applications Using Combinatorial Strategies

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2017年第1期32卷 199-210页

作者： Xiao-Fang Qi Zi-yuan wang Jun-Qiang Mao Peng wang School of Computer Science and Engineering Southeast University Nanjing 211189 China Key Laboratory of Computer Network and Information Integration Ministry of Education Nanjing 211189 China School of Computer Science and Technology Nanjing University of Posts and Telecommunications Nanjing 210023 China

Recently, testing techniques based on dynamic exploration, which try to automatically exercise every possible user interface element, have been extensively used to facilitate fully testing web applications. Most of such testing tools are however not effective in reaching dynamic pages induced by form interactions due to their emphasis on handling client-side scripting. In this paper, we present a combinatorial strategy to achieve a full form test and build an automated test model. We propose an algorithm called pairwise testing with constraints （PTC） to iraplement the strategy. Our PTC algorithm uses pairwise coverage and handles the issues of semantic constraints and illegal values. We have implemented a prototype tool ComjaxTest and conducted an empirical study on five web applications. Experimental results indicate that our PTC algorithm generates less form test cases while achieving a higher coverage of dynamic pages than the general pairwise testing algorithm. Additionally, our ComjaxTest generates a relatively complete test model and then detects more faults in a reasonable amount of time, as compared with other existing tools based on dynamic exploration.

关键词： automated testing combinatorial testing web application

Cyclotron dynamics of a Bose—Einstein condensate in a quadruple-well potential with synthetic gauge fields

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

Frontiers of physics 2021年第5期16卷 11-19页

作者： Wen-yuan wang Ji Lin Jie Liu Beijing Computational Science Research Center Beijing100193China Key Laboratory of Atomic and Molecular Physics&Functional Materials of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou730070China Department of Physics Zhejiang Normal UniversityJinhua321004China Graduate School of China Academy of Engineering Physics Beijing100193China HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking UniversityBeijing100871China

We investigate the cyclotron dynamics of Bose-Einstein condensate(BEC)in a quadruple-well potential with synthetic gauge *** use laser-assisted tunneling to generate large tunable effective magnetic fields for *** mean position of BEC follows an orbit that simulated the cyclotron orbits of charged particles in a magnetic *** the absence of atomic interaction,atom dynamics may exhibit periodic or quasi-periodic cyclotron *** the presence of atomic interaction,the system may exhibit self-trapping,which depends on synthetic gauge fields and atomic interaction *** particular,the competition between synthetic gauge fields and atomic interaction leads to the generation of several discontinuous parameter windows for the transition to self-trapping,which is obviously different from that without synthetic gauge fields.

关键词： cyclotron dynamics Bose-Einstein condensate quadruple-well potential synthetic gauge fields

3D FEM Analyses on Flow Field Characteristics of the Valveless Piezoelectric Pump

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2016年第4期29卷 825-831页

作者： HUANG Jun ZHANG Jianhui SHI Weidong wang yuan National Research Center of Pumps Jiangsu University School of Mechanical and Electric Engineering Guangzhou University State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics College of Communication Engineering PLA University of Science and Technology

Due to the special transportation and heat transfer characteristics,the fractal-like Y-shape branching tube is used in valveless piezoelectric pumps as a no-moving-part ***,there have been little analyses on the flow resistance of the valveless piezoelectric pump,which is critical to the performance of the valveless piezoelectric pump with fractal-like Y-shape branching *** field of the piezoelectric pump is analyzed by the finite element method,and the pattern of the velocity streamlines is revealed,which can well explain the difference of total flow resistances of the piezoelectric ***,simplified numerical method is employed to calculate the export flow rate of piezoelectric pump,and the flow field of the piezoelectric pump is *** FEM computation shows that the maximum flow rate is 16.4 m L/*** with experimental result,the difference between them is just 55.5%,which verifies the FEM *** reasons of the difference between dividing and merging flow resistance of the valveless piezoelectric pump with fractal-like Y-shape branching tubes are also investigated in this *** proposed research provides the instruction to design of novel piezoelectric pump and a rapid method to analyse the pump flow rate.

关键词： piezoelectric pump valveless fractal-like Y-shape branching tube FEM