检索结果-南通市图书馆

Liutex-based analysis of drag force and vortex in two-phase flow past 2-D square obstacle using LBM on GPU

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第5期32卷 820-833页

作者： Peng-xin Cheng Nan Gui Xing-tuan Yang ji-yuan Tu Sheng-yao jiang Hai-jun jia Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China School of Engineering RMIT UniversityMelbourneAustralia

The two-phase flow past a square is a ubiquitous phenomenon widely encountered in industries and engineering,where the interaction of disparate phases coupled with the influence of the solid is rather *** this context,the flow characteristics and the vortex field are investigated to reveal the mechanisms of the two-phase drag and the vortex *** lattice Boltzmann method(LBM)is utilized to study the multi-component two-phase *** computation implemented on the GPU is remarkably accelerated thanks to the natural parallelism of the *** process of the two-phase flow past a square is thoroughly *** drag and lift forces,including the total force and the components caused by the dispersed phase and the continuous phase,respectively,are obtained,and their variation mechanisms are ***,the vortex-identification approaches based on the Liutex as well as the traditional methods are *** relationship between the bubble breakup and coalescence processes and the extremums of different vortex identification variables is analyzed.

关键词： Two-phase flow flow past a square lattice Boltzmann method(LBM) vortex identification Liutex two-phase drag

MMP-2、TIMP-2在食管鳞状细胞癌的表达与临床意义

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

蚌埠医学院学报 2017年第3期42卷 297-301页

作者：袁继宝庞瑶熊海科朱自江薛继军朱小康赵海龙郑凤长甘肃中医学院临床医学院甘肃兰州730000 泰山医学院附属成武医院胸外科甘肃省肿瘤医院胸外科甘肃兰州730050 甘肃省人民医院胸外科甘肃兰州730000

目的:探讨基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶抑制剂-2(TIMP-2)在食管鳞状细胞癌(ESCC)中的表达与术后复发或转移和预后之间的关系。方法:采用组织芯片技术,用免疫组织化学法检测ESCC术后存活5年以上且无复发转移组(A组)和术后在... 详细信息

目的:探讨基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶抑制剂-2(TIMP-2)在食管鳞状细胞癌(ESCC)中的表达与术后复发或转移和预后之间的关系。方法:采用组织芯片技术,用免疫组织化学法检测ESCC术后存活5年以上且无复发转移组(A组)和术后在1年内发生复发转移死亡组(B组)肿瘤组织细胞中的MMP-2、TIMP-2表达情况。结果:MMP-2、TIMP-2在正常食管鳞状上皮中不表达或少量表达,在ESCC组织中有不同程度的表达,但MMP-2和TIMP-2在B组的表达水平均显著高于A组(P<0.01)。MMP-2表达与肿瘤分化程度和有无淋巴结转移均有相关关系(P<0.05和P<0.01);TIMP-2表达与分化程度和有无淋巴结转移率亦均有相关关系(P<0.01和P<0.05)。TIMP-2表达与MMP2表达呈正相关关系(P<0.01)。结论:MMP-2、TIMP-2表达在食管癌组织中高表达,其表达情况与食管癌术后发生复发转移有明显相关性,联合检测MMP-2、TIMP-2表达对预测ESCC术后发生复发转移和预后有重要价值。

关键词：食管肿瘤基质金属蛋白酶-2 基质金属蛋白酶抑制剂-2 复发转移

Tillage force and disturbance characteristics of different geometric-shaped subsoilers via DEM

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2020年第3期8卷 392-404页

作者： jin Tong Xiao-Hu jiang Yue-Ming Wang Yun-Hai Ma jun-Wei Li ji-Yu Sun Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun130022People’s Republic of China College of Biology and Agricultural Engineering Jilin UniversityChangchun130022People’s Republic of China College of Mechanical and Electrical Engineering Shihezi UniversityShihezi832000XinjiangPeople’s Republic of China

With the increased use of agricultural machinery in field operations,soil compaction has become increasingly severe,and the plough pan has become *** is an excellent way to address this ***,it is limited by high energy consumption,which is closely related to tillage *** investigate the effect of the geometric shape of shanks and tines on tillage force and soil disturbance in loam,a layered soil model in accordance with the actual conditions was established and five different subsoilers were simulated via discrete element *** results indicated that the shank impacted soil disturbance and tine impacted tillage *** draft force of curved shank and chisel tine was 8%less than that of the straight shank and sweep *** straight shank and sweep tine produced a larger furrow profile and a higher furrow *** subsoiler with curved shank and chisel tine(C-C)exhibited the lowest specific resistance(12.87,17.52,19.46 and 21.18 kN/m^2 in the 30,35,40 and 45 cm tillage depth,respectively)considering the draft force and soil disturbance ***,these results will facilitate in the selection of a suitable subsoiler and design of new subsoilers with lower energy consumption requirements for loam areas worldwide.

关键词： Subsoiler Discrete element method(DEM) Tillage force Soil disturbance Soil compaction

Nonlinear Out-of-Plane Mechanical Behaviours of Rectangular Woven Composite Flexible Skin Under Uniform Normal Pressure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2023年第5期36卷 672-684页

作者： Di Chen jun-jiang Xiong School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Transportation Science and Engineering Beihang UniversityBeijing 102206China

This paper seeks to investigate nonlinear out-of-plane mechanical behaviours of woven composite flexible skin(WCFS)through experimental and theoretical ***,quasi-static experiments are carried out on rectangular WCFSs with different aspect ratios under uniform normal pressure to measure out-of-plane deformation and failure ***,a new three-parameter geometric model is presented to describe 3D geometry of pressurized WCFS,and thus,a nonlinear mechanical model is deduced for depicting the relationship between pressure and out-of-plane *** application of the aforementioned models for experimental results shows that the new models have adequately and logically depicted deformation geometry and nonlinear mechanical characteristics.

关键词： Woven compositeﬂexible skin Nonlinear performance Uniform normal pressure Geometric model Mechanical model Aspect ratio

New constitutive relation for eddy viscosity models

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

航空动力学报 2016年第10期31卷 2485-2492页

作者： jiang Li-jun GAO Ge Hunan Aviation Powerplant Research Institute Aero Engine Corporation of China School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

A new turbulent constitutive relation was directly derived from Boussinesqs hypothesis and mixing length theory,and then implemented in the standard k-ε *** performance of this constitutive relation was validated in zero pressure gradient flat-plate boundary layer flow,fully-developed turbulent channel flow and separated flow in a plane asymmetric *** investigation demonstrated that,this new constitutive relation gave very accurate results in the former two basic cases and provided significant improvement in prediction of separated and reattachment points in the plane asymmetric *** and reattachment points at x/H =7.5and 29 were calculated accurately in comparison to experimental results,and the static pressure coefficient of 0.82 was very close to large eddy simulation *** results are very encouraging but further verification and extensive application of the new constitutive relation to other two-equation eddy viscosity model are needed.

关键词： constitutive relation turbulence model flat-plate flow channel flow separated flow

A method to Estimate Dynamic Responses of VLFS Based on Multi-Floating-Module Model Connected by Elastic Hinges

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2021年第5期35卷 687-699页

作者： HUANG Heng CHEN Xu-jun LIU jun-yi MIAO Yu-ji ji Song College of Field Engineering Army Engineering University of PLANanjing 210007China China Ship Scientific Research Center Wuxi 214082China

Based on the elastic foundation beam theory and the multi-floating-module hydrodynamic theory,a novel method is proposed to estimate the dynamic responses of VLFS(Very Large Floating Structure).In still water,a VLFS can be simplified as an elastic foundation beam model or a multi-floating-module model connected by elastic *** to equivalent displacement of the two models in static analysis,the problem of rotation stiffness of elastic hinges can be ***,based on the potential flow theory,the dynamic responding analysis of multi-floatingmodule model under wave loads can be computed in ANSYS-AQWA *** assembling the time domain analysis results of each module,the dynamic responses of the VLFS can be *** of the method is conducted through a series of comparison calculations,which mainly includes a continuous structure and a three-part structure connected by hinges in regular *** results of this paper method show a satisfactory agreement with the experiment and calculation data given in relative references.

关键词： Very Large Floating Structure(VLFS) dynamic responses elastic foundation beam multi-floatingmodule model elastic hinge

Revisiting the sex pheromone of the fall armyworm Spodoptera frugiperda,a new invasive pest in South China

在线全文

学校读者我要写书评

暂无评论

Insect Science 2022年第3期29卷 865-878页

作者： Nan-ji jiang Bao-Tong Mo Hao Guo jun Yang Rui Tang Chen-Zhu Wang State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijing100101China CAS Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijing100049China

The fall armyworm Spodoptera frugiperda is a worldwide serious agricultural pest,and recently invaded South *** pheromone can be employed to monitor its population dynamics accurately in the ***,the pheromone components previously reported by testing different geographic populations and strains are not *** the basis of confirming that the *** population from Yunnan Province belonged to the com strain,we analyzed the potential sex pheromone components in the pheromone gland extracts of females using gas chromatography coupled with electroan-tennographic detection(GC-EAD),gas chromatography coupled with mass spectrometry(GC-MS)and electroantennography(EAG).The results show that(Z)-9-tetradecenal acetate(Z9-14:Ac),(Z)-11-hexadecenyl acetate(Z11-16:Ac),(Z)-7-dodecenyl acetate(Z7-12:Ac)or(E)-7-dodecenyl acetate(E7-12:Ac)with a ratio of 100:15.8:3.9 induced EAD responses to varying degrees:Z9-14:Ac elicited a strong EAD response,Z7-12:Ac or E7-12:Ac elicited a small but clear EAD response,while Z11-16:Ac elicited a weak EAD *** single sensillum recording(SSR)showed that Z9-14:Ac and Z7-12:Ac induced dose-dependent activities in two types(A and B)of sensilla in male antennae,respectively,while the sensilla in response to E7-12:Ac and Z11-16:Ac was not ***,wind tunnel tests reveal that Z9-14:Ac and Z7-12:Ac are two principal sex pheromone components of the tested population.

关键词： GC-EAD GC-MS sex pheromone single sensillum recording wind tunnel

Evidence of Evolution in the Dense Cores in Massive Star Forming Regions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2005年第4期5卷 363-370页

作者： jian-jun Zhou Jarken Esimbek ji-Xian Sun Bing-Gang Ju jing-jiang Sun National Astronomical Observatories/Urumqi observatory Chinese Academy of SciencesUrumqi 830011 Graduate School of the Chinese Academy of Science Beijing 100080 Qinghai Station of Purple mountain Observatory Chinese Academy of Science DelinghaQinghai 817000

The excitation of H2O masers usually needs very high density gas,hence it can serve as a marker of dense gas in HⅡ region. We selected a sample of H2O maser sources from Plume et al. （four with, and four without detected CS（J = 7 - 6） emission）, and observed them in ^13CO（J=1-0） and C^18O （J=1-0）. C^18O （J=1-0） emission was detected only in three of the sources with detected CS（J=7-6） emission. An analysis combined with some data in the literature suggests that these dense cores may be located at different evolutionary stages. Multi-line observation study may provide us clues on the evolution of massive star forming regions and the massive stars themselves.

关键词： ISM: molecules - masers - radio lines: ISM-stars: formation

Fractal Prediction Model of Thermal Contact Conductance of Rough Surfaces

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2013年第1期26卷 128-136页

作者： ji Cuicui ZHU Hua jiang Wei School of Mechanical and Electrical Engineering China University of Mining and Technology School of Mechanical Engineering University of Leeds

The thermal contact conductance problem is an important issue in studying the heat transfer of engineering surfaces, which has been widely studied since last few decades, and for predicting which many theoretical models have been established. However, the models which have been existed are lack of objectivity due to that they are mostly studied based on the statistical methodology characterization for rough surfaces and simple partition for the deformation formats of contact asperity. In this paper, a fractal prediction model is developed for the thermal contact conductance between two rough surfaces based on the rough surface being described by three-dimensional Weierstrass and Mandelbrot fractal function and assuming that there are three kinds of asperity deformation modes： elastic, elastoplastic and fully plastic. Influences of contact load and contact area as well as fractal parameters and material properties on the thermal contact conductance are investigated by using the presented model. The investigation results show that the thermal contact conductance increases with the increasing of the contact load and contact area. The larger the fractal dimension, or the smaller the fractal roughness, the larger the thermal contact conductance is. The thermal contact conductance increases with decreasing the ratio of Young＇s elastic modulus to the microhardness. The results obtained indicate that the proposed model can effectively predict the thermal contact conductance at the interface, which provide certain reference to the further study on the issue of heat transfer between contact surfaces.

关键词： rough surface fractal thermal contact conductance prediction model