检索结果-南通市图书馆

Fully Decoupled Branch Energy Balancing Control Method for Modular Multilevel Matrix Converter Based on Sequence Circulating Components

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第1期10卷 235-247页

作者： Zexin Zhao Weijiang Chen Zhichang Yang guoliang Zhao Bin Han Yunfei xu Nianwen Xiang Shulai Wang China Electric Power Research Institute Beijing 100192China State Grid Corporation of China Beijing 100031China State Grid Smart Grid Research Institute Beijing 102209China State Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research InstituteBeijing 102211China Hefei University of Technology Hefei 230009China

The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.

关键词： Branch energy balancing control decoupled control low-frequency AC transmission modular multilevel matrix converter(M3C) sequence circulating components

IKIP downregulates THBS1/FAK signaling to suppress migration and invasion by glioblastoma cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Oncology Research 2024年第7期32卷 1173-1184页

作者： ZHAOYING ZHU YANJIA HU FENG YE HAIBO TENG guoliang YOU YUNHUI ZENG MENG TIAN JIANGUO xu JIN LI ZHIYONG LIU HAO LIU NIANDONG ZHENG Department of Neurosurgery The Affiliated Hospital of Southwestern Medical UniversityLuzhouChina Department of Neurosurgery Sichuan University West China HospitalChengduChina

Background:Inhibitor of NF-κB kinase-interacting protein(IKIP)is known to promote proliferation of glioblastoma(GBM)cells,but how it affects migration and invasion by those cells is unclear.Methods:We compared levels of IKIP between glioma tissues and normal brain tissue in clinical samples and public databases.We examined the effects of IKIP overexpression and knockdown on the migration and invasion of GBM using transwell and wound healing assays,and we compared the transcriptomes under these different conditions to identify the molecular mechanisms involved.Results:Based on data from our clinical samples and from public databases,IKIP was overexpressed in GBM tumors,and its expression level correlated inversely with survival.IKIP overexpression in GBM cells inhibited migration and invasion in transwell and wound healing assays,whereas IKIP knockdown exerted the opposite effects.IKIP overexpression in GBM cells that were injected into mouse brain promoted tumor growth but inhibited tumor invasion of surrounding tissue.The effects of IKIP were associated with downregulation of THBS1 mRNA and concomitant inhibition of THBS1/FAK signaling.Conclusions:IKIP inhibits THBS1/FAK signaling to suppress migration and invasion of GBM cells.

关键词： Inhibitor of NF-κB kinase-interacting protein(IKIP) Glioblastoma(GBM) Migration Thrombospondin 1(THBS1) FAK signaling

Binary-ternary transition metal chalcogenides interlayer coupling in van der Waals type-II heterostructure for visible-infrared photodetector with efficient suppression dark currents

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第3期15卷 2689-2696页

作者： guoliang xu Danmin Liu Songyu Li Yi Wu Zhenlu Zhang Shaobo Wang Zikun Huang Yongzhe Zhang Key Laboratory of Advanced Functional Materials Ministry of EducationFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China School of Physics and Nuclear Energy Engineering Beihang UniversityBeijing 100083China School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Optoelectronics Technology Ministry of EducationFaculty of Information TechnologyBeijing University of TechnologyBeijing 100124China

Ternary two-dimentional(2D)materials exhibit diverse physical properties depending on their composition,structure,and thickness.Through forming heterostructures with other binary materials that show similar structure,there can be numerous potential applications of these ternary 2D materials.In this work,we reported the structure of few-layer CrPS_(4)by X-ray diffraction,transmission electron microscope,and electron-density distribution calculation.We also demonstrated a new application of the CrPS_(4)/MoS_(2)heterobilayer:visible-infrared photodetectors with type-II staggered band alignment at room temperature.The response of the heterostructure to infrared light results from a strong interlayer coupling that reduces the energy interval in the junction area.Since the intrinsic bandgap of individual components determines wavelengths,the decrease in energy interval allows better detection of light that has a longer wavelength.We used photoluminescence(PL)spectroscopy,Kelvin probe force microscopy(KPFM)under illumination,and electrical transport measurements to verify the photoinduced charge separation between the CrPS_(4)/MoS_(2)heterostructures.At forward bias,the device functioned as a highly sensitive photodetector,as the wavelength-dependent photocurrent measurement achieved the observation of optical excitation from 532 to 1,450 nm wavelength.Moreover,the photocurrent caused by interlayer exciton reached around 1.2 nA at 1,095 nm wavelength.Our demonstration of the strong interlayer coupling in the CrPS_(4)/MoS_(2)heterostructure may further the understanding of the essential physics behind binary-ternary transition metal chalcogenides heterostructure and pave a way for their potential applications in visible-infrared devices.

关键词： heterostructure MoS_(2) CrPS_(4) interlayer transition visible-infrared photodetector type-II band alignment

Effects of acid deposition on the avoidance behavior of Folsomia candida (Collembola, Isotomidae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Soil Ecology Letters 2022年第2期4卷 164-170页

作者： Xiaofeng Luo Linglong Zhu guoliang xu Jiaen Zhang Jianlong xu Shiqin Yu Xiaohua Chen School of Geographical Science and Remote Sensing Guangzhou UniversityGuangzhou 510006China Guangdong Province Rural Water Environment Non-point Source Pollution Comprehensive Treatment Engineering Technology Research Center Guangzhou 510006China Guangdong Provincial Key Laboratory of Eco-circular Agriculture South China Agricultural UniversityGuangzhou 510642China

Excessive acid deposition causes soil acidification,and changes the soil microhabitat,thus affecting the survival and reproduction of soil organisms.Folsomia candida(Collembola,Isotomidae),as a model organism,is widely used to assess the chemical toxicity in soil,and its avoidance response can indicate the environmental changes.In this study,we used Folsomia candida to assess the risks of acid deposition on soil ecosystems.Different pH(3.0,3.5,4.0,4.5,5.0,and 5.5)treatments were set up in petri dish experiments,and the avoidance behavior of Folsomia candida was measured after 12,24,and 48 h exposure to the pH conditions.The results indicated that(1)both the exposure duration and pH level influenced avoidance behavior of collembolan.(2)After 12 h exposure,most of the individuals showed avoidance behavior but without significant differences among the treatments.(3)After 24 h exposure,significant avoidance behavior was observed at pH 3.0,3.5,and 4.0.(4)After 48 h exposure,avoidance behavior was found in all treatment conditions except for pH 5.5.This study clarified the direct responses of soil fauna to acid deposition,and indicated that both pH and length of exposure influenced the avoidance behavior of Folsomia candida.During the experimental period,the collembolan reacted negatively and showed consistent avoidance behavior at pH 3.0,3.5,and 4.0.Reversed avoidance behavior was apparent between pH 4.5 and 5.0 and not observed at pH 5.5,indicating that the latter was the preferred pH environment.

关键词： Collembolan Acid rain Behavioral avoidance

维普期刊数据库

CONSTRUCTION OF GEOMETRIC PARTIAL DIFFERENTIAL EQUATIONS FOR LEVEL SETS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2010年第1期28卷 105-121页

作者： Chong Chen guoliang xu LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Beijing 100190 China LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Geometric partial differential equations of level-set form are usually constructed by a variational method using either Dirac delta function or co-area formula in the energy functional to be minimized. However, the equations derived by these two approaches are not consistent. In this paper, we present a third approach for constructing the level-set form equations. By representing various differential geometry quantities and differential geometry operators in terms of the implicit surface, we are able to reformulate three classes of parametric geometric partial differential equations （second-order, fourth-order and sixth- order） into the level-set forms. The reformulation of the equations is generic and simple, and the resulting equations are consistent with their parametric form counterparts. We further prove that the equations derived using co-area formula are also consistent with the parametric forms. However, these equations are of much complicated forms than these given by the equations we derived.

关键词： Geometric partial differential equations Level set Differential geometry operators.

维普期刊数据库

Delayed detached eddy simulations of fighter aircraft at high angle of attack

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2016年第4期32卷 588-603页

作者： guoliang xu Xiong Jiang Gang Liu China Aerodynamics Research and Development Center

The massively separated flows over a realistic aircraft configuration at 40？, 50？, and 60？angles of attack are studied using the delayed detached eddy simulation（DDES）.The calculations are carried out at experimental conditions corresponding to a mean aerodynamic chord-based Reynolds number of 8.93 × 10~5 and Mach number of 0.088. The influence of the grid size is investigated using two grids, 20.0×10~6cells and 31.0 × 10~6 cells. At the selected conditions, the lift,drag, and pitching moment from DDES predictions agree with the experimental data better than that from the Reynoldsaveraged Navier–Stokes. The effect of angle of attack on the flow structure over the general aircraft is also studied, and it is found that the dominated frequency associated with the vortex shedding process decreases with increasing angle of attack.

关键词： aircraft turbulent Reynolds vortex turbulence averaged Navier unsteady realistic chord

维普期刊数据库

习近平文化思想视域下中华优秀传统文化国际传播的四重维度

在线全文

学校读者我要写书评

暂无评论

浙江工商大学学报 2024年第3期 36-46页

作者：徐国亮薛伟山东大学马克思主义学院山东济南250100

习近平文化思想为中华优秀传统文化国际传播指明了方向。中华优秀传统文化国际传播,在价值之维上,有助于推动理论发展、扩大文化影响、加强文化认同、促进文化发展;在内容之维上,其传播内容包括天人合一的宇宙观、协和万邦的天下观、和... 详细信息

习近平文化思想为中华优秀传统文化国际传播指明了方向。中华优秀传统文化国际传播,在价值之维上,有助于推动理论发展、扩大文化影响、加强文化认同、促进文化发展;在内容之维上,其传播内容包括天人合一的宇宙观、协和万邦的天下观、和而不同的社会观、人心和善的道德观等;在条件之维上,其传播条件包括国家实力增强、国际地位上升、数媒技术成熟、文化发展需要;在实践之维上,其传播路径包括强化传播主体、明晰传播对象、创新传播话语、优化传播媒介、用好传播平台。四重维度是系统的整体,价值之维明晰了国际传播意义,内容之维规定了国际传播要义,条件之维确定了国际传播基础,实践之维是价值之维、内容之维及条件之维在现实中的展开。

关键词：习近平文化思想中华优秀传统文化国际传播国际话语权

维普期刊数据库博看期刊

A Four-Equation Eddy-Viscosity Approach for Modeling Bypass Transition

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2014年第4期6卷 523-538页

作者： guoliang xu Song Fu China Aerodynamics Research and Development Center Mianyang 621000China School of Aerospace Tsinghua UniversityBeijing 100084China

It is very important to predict the bypass transition in the simulation of flows through turbomachinery.This paper presents a four-equation eddy-viscosity turbulence transition model for prediction of bypass transition.It is based on the SST turbulence model and the laminar kinetic energy concept.A transport equation for the non-turbulent viscosity is proposed to predict the development of the laminar kinetic energy in the pre-transitional boundary layer flow which has been observed in experiments.The turbulence breakdown process is then captured with an intermittency transport equation in the transitional region.The performance of this new transition model is validated through the experimental cases of T3AM,T3A and T3B.Results in this paper show that the new transition model can reach good agreement in predicting bypass transition,and is compatible with modern CFD software by using local variables.

关键词： Bypass transition non-turbulent viscosity free stream turbulence turbulence model

Bird community comparisons of four plantations and conservation concerns in South China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2014年第1期9卷 97-106页

作者： Fasheng ZOU Qiongfang YANG Yongbiao LIN guoliang xu Russell GREENBERG Guangdong Entomological Institute GuangzhouChina South China Institute of Endangered Animals GuangzhouChina South China Botanical Garden Chinese Academy of SciencesGuangzhouChina Smithsonian Migratory Bird Centre National Zoological ParkWashingtonDCUSA

Plantations of non-native,fast-growing trees are increasing in the tropics and subtropics,perhaps with negative consequences for the native avifauna.We studied bird diversity in 4 types of plantations in South China to deter-mine which plantation types are especially detrimental,and compared our findings with studies in nearby natu-ral forests to assess the magnitude of the negative impact.A total of 57 species was recorded.The mean capture rate of understory birds was 1.7 individuals 100-net-h-1.Bird richness and capture rate were lower in plantations than in nearby natural forests.Babblers(Timaliidae),primarily forest-dependent species in South China,were particularly under-represented in plantations.Species richness,composition and bird density,particularly of un-derstory birds,differed between plantation types.Plantations of Schima,which is native to South China,had the highest species richness according to point count data.Plantations of Acacia(non-native)supported the highest understory species richness and produced the highest capture rate of understory birds,probably because of their complex structure and high arthropod abundance.If bird diversity is to be considered,we strongly recommend that future re-afforestation projects in South China should,as far as possible,use mixed native tree species,and especially Schima,ahead of the other species.

关键词： babbler conservation bird community changing planting ways plantations tree species selection