检索结果-南通市图书馆

Visualization Investigation on Flowing Condensation in Horizontal Small Channels with Liquid Separator

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 Thermal Science 2018年第1期27卷 48-54页

作者： ZHANG xuan JIA Li dang Chao PENG Qi Institude of Thermal Engineering School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing key laboratory of flow and heat transfer of phase changing in micro and small scale Beijing 100044China

A simultaneous visualization and measurement experiment was carried out to investigate condensation flow pat- terns and condensing heat transfer characteristics of refrigerant R14 lb in parallel horizontal multi-channels with liquid-vapor separator. The hydraulic diameter of each channel was 1.5 mm and the channel length was 100 ram. The refrigerant vapor flowing in the small channels was cooled by cooling water. The parallel horizontal mul- ti-channels were covered with a transparent silica glass for visualization of flow patterns. Experiments were per- formed at different inlet superheat temperatures （ranging from 3~C to 7~C）. Mass velocity was in the range of 82.37 kg mZs1 to 35.56 kg m-2s1. It was found that there were three different flow patterns through the mul- ti-channels with the increase of mass velocity. The flow patterns in each channel pass almost tended to be same and all of them were annular flows.＇ The efficiency of the liquid-vapor separator with U-type was related to vapor mass velocity and the pressure in the small channels. It was also found that the heat transfer coefficient increased with the increase of the mass velocity while the cooling water mass flow rate increased. It increased to a top point and then decreased. It increased with the increase of superheat in the low superheat temperature region.

关键词： condensation visualization multi-channels liquid-vapor separation

Thermal Performance Prediction in the Air Gap of a Rotor-Stator Configuration: Effects of Numerical Models

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2020年第1期29卷 206-218页

作者： dang Dinh-Dong PHAM xuan-Tan NGUYEN Chi-Cong Department of Mechanical Engineering École de technologie supérieureMontrealQCCanada Hydro-Québec’s research institute VarennesQCCanada

This study is dedicated to a numerical investigation of convective heat transfer on the rotor surfaces of a rotor-stator configuration that is typically found in large *** computational fluid dynamics calculations with two turbulence modelling approaches are used to predict the flow structure and heat transfer in the air gap of the rotor-stator *** steady state mixing plane approach is employed at the interface to couple the rotor and stator *** show that the location of mixing plane interface in the air gap plays an important role in the prediction of heat transfer on the pole ***,it is indicated that the prediction of temperature distribution on the pole face is greatly affected by the turbulence models ***,through a comparison between the pure convective and conjugate heat transfer methodologies,it is shown that the inclusion of solid domain into the numerical model significantly improves the thermal prediction of the solid components of the machine.

关键词： hydro-generators electrical cooling mixing plane windage loss conjugate heat transfer

Characterization of random stress fields obtained from polycrystalline aggregate calculations using multi-scale stochastic finite elements

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2015年第2期9卷 121-140页

作者： Bruno SUDRET Hung xuan dang Marc BERVEILLER Asmahana ZEGHADI Thierry YALAMAS Risk Safety and Uncertainty Quantification ETH Zurich Stefano-Franscini-Platz 5 Zurich CH-8093 Switzerland Phimeca Engineering S.A. Centre d'affaires du Zenith 34 rue de Sarlieve Cournon F-63800 France EDF R&D Dept. of Materials and Mechanics of Components Site des Renardieres Moret-sur-Loing Cedex 77250 France

The spatial variability of stress fields resulting from polycrystalline aggregate calculations involving random grain geometry and crystal orientations is investigated. A periodogram-based method is proposed to identify the properties of homogeneous Gaussian random fields (power spectral density and related covariance structure). based on a set of finite element polycrystalline aggregate calculations the properties of the maximal principal stress field are identified. Two cases are considered, using either a fixed or random grain geometry. The stability of the method w.r.t the number of samples and the load level (up to 3.5% macroscopic deformation) is investigated.

关键词： polycrystalline aggregates crystal plasticity random fields spatial variability correlation structure

Role of the ejaculatory bulb in biosynthesis of the male pheromone cis-vaccenyl acetate in Drosophila melanogaster

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 2007年第2期2卷 89-99页

作者： Gaëlle GUIRAUDIE-CAPRAZ dang ba PHO Jean-Marc JALLON UnitéMixte de Recherche Universitéde Paris-Sud et Centre National de la Recherche Scientifique n°8620 University of Paris SudOrsayFrance

In Drosophila melanogaster,the male ejaculatory bulb is the site of synthesis of a male-specific pheromone,cis-vaccenyl acetate,which functions as both an attractant and an *** long monounsaturated acetate is structurally similar to a number of shorter gland-synthesized moth *** cell monolayer that forms the Drosophila male ejaculatory bulb wall is responsible for the production and secretion of cis-vaccenyl acetate into the seminal *** dissected bulbs were incubated with sodium[14-C]-acetate(or deuterated acetate),a labeled acetate ester was *** labeled acetate ester co-migrated with cis-vaccenyl acetate in thin layer *** of the abdomens of males from which the ejaculatory bulbs had been removed,or the abdomens of females,with radiolabeled acetate did not yield any acetate ester,but did yield other lipid products,including *** the isolated labeled acetate ester was hydrolyzed,no radioactive vaccenol was *** strongly suggests that the acetyl group is incorporated via a transacetylation reaction,but that the vaccenyl moiety is not synthetized in the *** transacetylation enzyme activity was localized in the microsomal subfraction of the bulb homogenate,and its affinity for vaccenol was not very different from that reported for monounsaturated alcohol substrates in moths.

关键词： cis-vaccenyl acetate Drosophila melanogaster ejaculatory bulb male pheromone microsomes transacetylation

Spatiotemporal Trend Analysis of Precipitation Extremes in Ho Chi Minh City, Vietnam During 1980–2017

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 Disaster Risk Science 2021年第1期12卷 131-146页

作者： Nguyen Trong Quan Dao Nguyen Khoi Nguyen xuan Hoan Nguyen Ky Phung Thanh Duc dang Faculty of Environmental and Food Engineering Nguyen Tat Thanh UniversityHo Chi Minh City 700000Vietnam Faculty of Environment University of ScienceHo Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Ho Chi Minh City University of Food Industry Ho Chi Minh City 700000Vietnam Institute for Computational Science and Technology Ho Chi Minh City 700000Vietnam Engineering Systems and Design Pillar Singapore University of Technology and DesignTampines 487372Singapore

In this study,the spatiotemporal variability of trends in extreme precipitation events in Ho Chi Minh City during the period 1980–2017 was analyzed based on several core extreme precipitation indices(Rx1 day,Rx5 day,CDD,CWD,R20 mm,R25 mm,R95 p,and SDII).The nonparametric Mann–Kendall and Sen’s slope methods were used to compute the statistical strength,stability,and magnitude of trends in annual rainfall,as well as the extreme precipitation *** found that 64%of the stations had statistically significant upward trends in yearly rainfall,with high magnitudes frequently observed in the northern and southern regions of the *** the extreme precipitation indices,only SDII and R25 mm showed dominantly significant ***,there were increasing trends in the frequency and duration at the southern and central regions of the city during the study ***,El Ni?o-Southern Oscillation and Pacific Decadal Oscillation positively correlated with the duration and negatively correlated with the intensity and frequency of extreme ***,water management plans should be adjusted appropriately to reduce the severe impacts of precipitation extremes on communities and ecosystems.

关键词： Spatiotemporal trend Extreme precipitation Extreme precipitation indices Ho Chi Minh City

A Novel Method for Resolving and Completing Authors' Country Affiliation Data in Bibliographic Records

在线全文

学校读者我要写书评

暂无评论

Journal of Data and Information Science 2020年第3期5卷 97-115页

作者： ba xuan Nguyen Jesse David Dinneen Markus Luczak-Roesch School of Information Management Victoria University of WellingtonWellingtonNew Zealand Posts and Telecommunications Institute of Technology Ho Chi Minh CityVietnam Berlin School of Library and Information Science Humboldt-Universitat zu BerlinBerlinGermany Te Punaha Matatini-The New Zealand Centre of Research Excellence for Complex Systems and Networks New Zealand

Purpose: Our work seeks to overcome data quality issues related to incomplete author affiliation data in bibliographic records in order to support accurate and reliable measurement of international research collaboration(IRC).Design/methodology/approch: We propose, implement, and evaluate a method that leverages the Web-based knowledge graph Wikidata to resolve publication affiliation data to particular countries. The method is tested with general and domain-specific data ***: Our evaluation covers the magnitude of improvement, accuracy, and consistency. Results suggest the method is beneficial, reliable, and consistent, and thus a viable and improved approach to measuring *** limitations: Though our evaluation suggests the method works with both general and domain-specific bibliographic data sets, it may perform differently with data sets not tested here. Further limitations stem from the use of the R programming language and R libraries for country identification as well as imbalanced data coverage and quality in Wikidata that may also change over *** implications: The new method helps to increase the accuracy in IRC studies and provides a basis for further development into a general tool that enriches bibliographic data using the Wikidata knowledge ***: This is the first attempt to enrich bibliographic data using a peer-produced, Webbased knowledge graph like Wikidata.

关键词： International research collaboration measurement Bibliographic data Country identification Knowledge graphs Wikidata Open data

Micro-pore Structure and Gas Accumulation Characteristics of Shale in the Longmaxi Formation, Northwest Guizhou

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2016年第2期1卷 191-204页

作者： Bing Xue Jinchuan Zhang xuan Tang Chao Yang Qian Chen Xiangjie Man Wei dang School of Energy Resources China University of GeosciencesBeijing 100083China Key Laboratory of Shale Gas Exploration and Evaluation Ministry of Land and ResourcesBeijing 100083China CNPC Greatwall Drilling Company Beijing 100101China

For further study on characteristics of micro-pores in the marine shale reservoirs in Northwest Guizhou,shale samples in the Lower Silurian Longmaxi Formation were selected to investigate effect of micro-pores on the characteristics of gas accumulation in shales,through methods of the argon broad ion beam-field emission scanning electron microscope and the nitrogen adsorption/desorption,analysis on the characteristics of micro-pores and related geochemical *** show that there are seven types of pores in the Longmaxi Formation shale,including interparticle pores,intraparticle pores,intercrystalline pores,dissolution pores,fossil pores,organic pores,and microfractures,among which the interparticle pores and organic pores are best *** to the nitrogen adsorption/desorption curves,the pore structures can be classified into three types,including the cylindrical pores with both opening ends,narrow parallel-plate pores and tapered parallel-plate pores with four opening *** of micro-pores ranges from 2 to 64 nm,mainly at 2-6 *** diameter of micro-pores(less than 2 nm)ranges from 0.4 to 1.8 nm,The micro-pores with a diameter of 0.4-1.0 nm contribute most to the pore *** volume is dominated by meso-pores(2-50 nm)with a proportion of 83.1%.The micro-pores and meso-pores make major contribution to the specific surface area of pores with proportions of 20.1%and 79.3%,*** total organic carbon(TOC)is the major factor controlling development of *** pore types have different characteristics of gas occurrence and migration,indicating that nanopores provide favorable conditions for the occurrence and microscopic migration of gas in shales.

关键词： Northwest Guizhou Longmaxi Formation lower Silurian argon broad ion beam-field emission scanning electron microscope nitrogen adsorption/desorption pore structure

Pore-scale mechanisms and characterization of light oil storage in shale nanopores:New method and insights

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2022年第5期13卷 50-58页

作者： Wei dang Haikuan Nie Jinchuan Zhang xuan Tang Shu Jiang Xiaoliang Wei Yang Liu Fengqin Wang Pei Li Zhipeng Chen Shaanxi Key Laboratory of Petroleum Accumulation Geology Xi’an Shiyou UniversityXi’an 710065China School of Earth Sciences and Engineering Xi’an Shiyou UniversityXi’an 710065China Petroleum Exploration and Production Research Institute SINOPECBeijing 100083China School of Energy Resources China University of GeosciencesBeijing 100083China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan 430074China Exploration and Development Institute of Shengli Oil Field Company SINOPECDongying 257000China Key Laboratory of Strategy Evaluation for Shale Gas Ministry of Land and ResourcesChina University of GeosciencesBeijing 100083China

A new method is proposed to analyze the pore-scale mechanisms and characterization of light oil storage in shale nanopores,which is based on the Hydrocarbon Vapor Adsorption(HVA)and Pore Calculation Model(PCM).First,the basic principle of the HVA-PCM method is introduced,and the experimental/mathematical analysis processes are ***,the HVA-PCM method is applied to shale samples to analyze the mechanisms and characterization of light oil storage in shale *** results provide insights into the pore-scale oil storage mechanisms,oil storage structure,oil film thickness,oil distribution within different sized pores,and the oil storage ***,the advantages and limitations of the HVA-PCM method are discussed,and suggestions for further improvement are ***,the HVA-PCM method is a powerful tool for extracting quantitative information on the light oil storage in shale nanopores.

关键词： Shale oil Storage mechanisms Storage characterization Hydrocarbon vapor adsorption

在线全文

学校读者我要写书评

暂无评论

压电陶瓷执行器的神经网络实时自适应逆控制

光学精密工程 2008年第7期16卷 1266-1272页

作者：党选举桂林电子科技大学智能系统与工业控制研究室广西桂林541004

提出了基于内积的压电陶瓷动态神经网络非线性、非光滑迟滞逆模型,采用反馈误差学习方法,快速地在线得到压电陶瓷的逆模型,避免了通过正模型求取压电陶瓷的Jacobian信息。结合PID反馈控制,在dSPACE系统平台上实现了压电陶瓷的神经网络... 详细信息

提出了基于内积的压电陶瓷动态神经网络非线性、非光滑迟滞逆模型,采用反馈误差学习方法,快速地在线得到压电陶瓷的逆模型,避免了通过正模型求取压电陶瓷的Jacobian信息。结合PID反馈控制,在dSPACE系统平台上实现了压电陶瓷的神经网络自适应逆控制。为提高实时性,采用了效率高、速度快的C-MEX S Function编程。实验结果表明:神经网络自适应逆控制的控制精度为0.13μm,而PID控制精度为0.32μm。所提出方法有效地消除了迟滞的影响,控制精度高。

关键词：匪电陶瓷迟滞特性神经网络自适应逆控制 dSPACE系统非光滑迟滞逆模型