检索结果-南通市图书馆

上海交通大学学报 2004年第z2期38卷 229-234页

作者： Deng qilin zhang Lei Zhou Jinjin Shanghai Jiaotong University Shanghai 200030 China Dalian University of Technology Dalian 116024 China Dalian University of Technology Dalian 116024 China

Filth adhering to metal pipes can be cleaned by shock wave generated by electrical discharge under water. The mechanism of shock wave effect of electrical discharge under water on filth cleaning is analyzed by building a mechanical model. A metal pipe coated with cement to simulate real filth is cleaned by using electrical discharge under water. The experimental results confirm the mechanical analysis and also show the technology of electrical discharge under water is an very effective method for filth cleaning.

关键词： shock wave filth cleaning effect of electrical discharge under water

Cyclic behavior of prefabricated reinforced concrete frame with infill slit shear walls

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 Structural and Civil Engineering 2016年第1期10卷 63-71页

作者： Kui XIAO qilin zhang Bin JIA Department of Building Engineering Tongji University Shanghai 200092 China

A composite structural system consisting of prefabricated reinforced concrete frame with infill slit shear walls （PRCFW）, with good ductility, is a new type of earthquake resistant structure. Pseudo-static tests were performed to evaluate the seismic behavior of the PRCFW system. Two one-bay, two-story PRCFW specimens were both built at one- half scale. Additional computational research is also conducted to enhance the nonlinear analytical capabilities for this system. Combined with the concrete damaged plastic （CDP） model provided by finite element program ABAQUS and the constitutive model of concrete proposed by Chinese code, the damage process of the PRCFW structure under cyclic load is simulated. The simulated results show a good agreement with the test data, the dynamic behavior of the PRCFW system can be simulated sufficiently accurate and efficient to provide useful design information. The experimental and numerical study show that this system has the potential to offer good ductility and energy absorption capacity to dissipate input energy, and stiffness adequate for controlling drift for buildings located in earthquake-prone regions.

关键词： slit shear wall constitutive model cyclic seismic damage

An ultra-thin bolt tension sensor and online monitoring system:For application in hydropower plant unit

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第9期18卷 1388-1400页

作者： Shaoquan zhang Yanke TAN Hanbin GE qilin zhang Department of Civil Engineering Meijo UniversityNagoya 4688502Japan College of Civil Engineering Tongji UniversityShanghai 200092China

The condition of bolted connections significantly affects the structural ***,conventional bolt tension sensors fail to provide precise measurements due to their bulky size or inadequate *** study employs the piezoresistive effect of crystalline silicon material to fabricate an ultrathin *** sensor exhibits a linear relationship between pressure and voltage,an exceptional stability at varying temperatures,and a superior resistance to corrosion,making it adaptable and user-friendly for applications of high-strength bolt tension monitoring.A monitoring system,incorporating the proposed sensor,has also been *** system provides real-time display of bolt tension and enables the assessment of sensor and structural conditions,including bolt loosening or component *** efficacy of the proposed sensor and monitoring system was validated through a project carried out at the Xiluodu Hydropower *** to the results,the sensor and online monitoring system effectively gauged and proficiently conveyed and stored bolt tension *** addition,correlations were created between bolt tensions and essential unit parameters,such as water head,active power,and pressures at vital points,facilitating anomaly detection and early warning.

关键词： ultra-thin sensor high-strength bolt tension online monitoring system anomaly alarm hydro-generator units

Simulated impacts of atmospheric gravity waves on the initiation and optical emissions of sprite halos in the mesosphere

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2019年第4期62卷 631-642页

作者： Jinbo zhang qilin zhang Xiufeng GUO Wenhao HOU Haiyang GAO Key Laboratory of Meteorological Disaster Ministry of Education (KLME) Joint International Research Laboratory of Climate and Environment Change (ILCEC) Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD)Key L aboratory for Aerosol-C loud-Precipitation of China Meteorological Administration Nanjing University of Information Science & Technology Nanjing 210044 China

The correlation between atmospheric gravity waves(GWs) and Transient Luminous Events(TLEs) has been poorly studied using both synchronous observations and numerical simulations. To investigate the modulation effects of GWs on TLEs,a troposphere-mesosphere quasi-electrostatic field model is developed in three-dimensional Cartesian coordinates, and the effects of GW perturbations on the initiation and optical emissions of sprite halos are simulated using the model. Simulation results indicate that the atmospheric density at lower ionosphere altitudes becomes inhomogeneous due to GW perturbations, and sprite halos tend to initiate in the GW troughs due to the lower electric breakdown threshold. GW perturbations cause the deformation of sprite halos, strong luminous regions distribute mainly along the GW troughs while optical intensities along the GW peaks is relatively weak. Larger GW perturbations lead to more pronounced deformation of sprite halos, however, stronger lightning discharges in the troposphere result in less optical perturbations of sprite halos. The observed luminous intensities and optical morphology of sprite halos are also affected by the observing orientations and the lightning polarities.

关键词： Three-dimensional quasi-electrostatic field model Sprite halos Optical emission Gravity waves

Experimental investigation and design of aluminum columns with longitudinal welds

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2011年第3期5卷 366-373页

作者： Yun WU qilin zhang Shanghai University of Electric Power Shanghai 200090China College of Civil Engineering Tongji UniversityShanghai 200092China

This paper presents an experimental investigation of longitudinally welded aluminum alloy I-section columns subjected to pure axial *** specimens were fabricated using 6061-T6 heat-treated aluminum *** test program included 20 column tests which were separated into 2 test series of different types of welding *** test series contained 10 *** the specimens were welded using the Tungsten Inert Gas welding *** length of the specimens ranged from 442 to 2433 mm in order to obtain a column curve for each test *** observed failure mode for the column tests includes mainly flexural buckling around the minor axis and the major axis by applying support except for one column(ZP 1217-1)which buckled in the local zone and some columns which failed in the *** test strengths were compared with the design strengths predicted by the European Code and China Code for aluminum *** purpose of this paper is to present the tests results of two typically longitudinally welded I-section columns,and to check the accuracy of the design rules in the current specifications.

关键词： aluminum alloy longitudinal weld heataffected zone(HAZ) reduced strength zone(RSZ) buckling column experimental study

Factors affecting poplar wetwood characteristics

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 Forestry Research 2023年第5期34卷 1615-1626页

作者： qilin zhang Xingyi Hu Qian Hu Jiawei Yang Tianyu Zhao Kebing Du College of Horticulture and Forestry Sciences/Hubei Engineering Technology Research Center for Forestry Information Huazhong Agricultural UniversityWuhan 430070People’s Republic of China Hubei Academy of Forestry Wuhan 430075People’s Republic of China Xiangyang Academy of Forestry Xiangyang 441052People’s Republic of China

Wet wood is an abnormal phenomenon in growing trees,which adversely affects growth,subsequent wood processing and economic values of wood *** this study,the influences of factors such as clones,afforestation methods,site conditions and climate conditions on the characteristics of poplar wetwood were studied through field investigations in 27 clones from 48 sample plots in 28 *** showed that the incidences of wetwood were almost 100%in all *** of wetwood area among the48 plots differed from 15.1 to 90.2%.Wetwood area ratios,moisture contents and pH differed significantly between the 27 *** area ratios of the clones ranged from18.7 to 62.3%.Ratios of wetwood areas were positively correlated with wet wood moisture content and pH,tree age,and negatively correlated with pH of sap *** repeatability of wet wood area ratios was 0.52,moderately controlled by *** moisture content and pH were highly controlled by genetics,indicated by the repeatability of 0.91 and 0.89,*** were significant differences in wetwood area ratios,moisture content and pH between different site conditions,afforestation methods,and geographical *** land had the lowest wetwood area ratios and moisture content among four types of *** by direct seeding and rooted cuttings had the lowest wetwood area ratios and moisture content,*** the three geographical regions,the Yellow River Basin had the lowest wetwood values of all three factors.

关键词： Poplar Wetwood Clones Site conditions Afforestation methods

Study of Aircraft Icing Warning Algorithm Based on Millimeter Wave Radar

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2017年第6期31卷 1034-1044页

作者： Jinhu WANG Junxiang GE qilin zhang Pan FAN Ming WEI Xiangchao LI Collaborative Innovation Center on Forecast and Evaluation of MeteorologicalDisasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing 210044 Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science&TechnologyNanjing 210044 Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science&TechnologyNanjing 210044 National Demonstration Center for Experimental Atmospheric Science and Environmental Meteorology Education Nanjing University of information Science&TechnologyNanjing 210044

In order to avoid accidents due to aircraft icing, an algorithm for identifying supercooled water was studied. Specifically, a threshold method based on millimeter wave radar, lidar, and radiosonde was used to retrieve the coverage area of supercooled water and a fuzzy logic algorithm was used to classify the observed meteorological targets. The macrophysical characteristics of supercooled water could be accurately identified by combing the threshold method with the fuzzy logic algorithm. In order to acquire microphysical characteristics of supercooled water in a mixed phase, the unimodal spectral distribution of supercooled water was extracted from a bimodal or trimodal spectral distribution of a mixed phase cloud, which was then used to retrieve the effective radius and liquid water content of supercooled water by using an empirical formula. These retrieved macro- and micro-physical characteristics of supercooled water can be used to guide aircrafts during takeoff, flight, and landing to avoid dangerous areas.

关键词： supercooled water aircraft icing millimeter wave radar threshold method fuzzy logic algorithm power spectral density

Artificially triggered lightning and its characteristic discharge parameters in two severe thunderstorms

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2007年第8期50卷 1241-1250页

作者： QIE XiuShu zhang qilin ZHOU YunJun FENG GuiLi zhang TingLong YANG Jing KONG XiangZhen XIAO QingFu WU ShuJun Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

The lightning-induced-damages in the mid-latitude regions are usually caused during severe thunderstorms. But the discharge parameters of natural lightning are difficult to be measured. Five lightning flashes have been artificially triggered with the rocket-wire technique during the passage of two severe thunderstorms. The discharge current and close electric field of return stroke in artificially triggered lightning have been obtained in microsecond time resolution by using current measuring systems and electric field change sensors. The results show that the five triggered lightning flashes include 1 to 10 return strokes, and the average return stroke current is 11.9 kA with a maximum of 21.0 kA and a minimum of 6.6 kA, similar to the subsequent return strokes in natural lightning. The half peak width of the current waveform is 39 us, which is much larger than the usual result. The peak current of stroke I_p(kA) and the neutralized charge Q(C) has a relationship of I_p = 18.5Q^(0.65). The radiation field of return stroke is 5.9 kV ? m^(-1) and 0.39 kV ? m^(-1) at 60 m and 550 m, respectively. The radiation field decreases as r^(-1.119) with increase of horizontal distance r from the discharge channel. Based on the well-accepted transmission line model, the speed of return stroke is estimated to be about 1.4 × 10~8m·s^(-1), with a variation range of (1.1-1.6)×10~8m·s^(-1). Because of the similarities of the triggered lightning and natural lightning, the results in this article can be used in the protection design of natural lightning.

关键词： artificially triggered lightning characteristic discharge parameters current waveform electric field change in close distance severe thunderstorm

Characteristics and mathematical models of the thin-layer drying of paddy rice with low-pressure superheated steam

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2023年第1期16卷 273-282页

作者： Yan Li Gang Che Lin Wan qilin zhang Tianqi Qu Fengzhou Zhao College of Engineering Heilongjiang Bayi Agricultural UniversityDaqing 163319HeilongjiangChina Heilongjiang Key Laboratory of Intelligent Agricultural Machinery Equipment Daqing 163319HeilongjiangChina College of Agriculture Heilongjiang Bayi Agricultural UniversityDaqing 163319HeilongjiangChina

Drying paddy with low-pressure superheated steam(LPSS)can effectively increase theγ-aminobutyric acid content in *** study aimed to investigate the characteristics and mathematical models(MMs)of thin-layer drying of paddy with *** experimentally obtained data wereﬁtted by nonlinear regression with 5 MMs commonly used for thin-layer drying to calculate the goodness of fit of the ***,the thin-layer drying of paddy with LPSS was modeled with two machine learning methods as a Bayesian regularization back propagation(BRBP)neural network and a support vector machine(SVM).The results showed that paddy drying with LPSS is a reduced-rate drying *** drying temperature and operating pressure have a significant impact on the drying *** the same pressure,increasing the drying temperature can accelerate the drying *** the same temperature,increasing the operating pressure can accelerate the drying *** comparison of the model evaluation indexes showed that 5 common empirical MMs(Hederson and Pabis,Page,Midilli,Logarithmic,and Lewis)for thin-layer drying can achieve excellent fitting effects for a single experimental ***,the regression fitting of the indexes by calculating the coefficient(s)of each model showed that the empirical MMs produce poor fitting *** BRBP neural network-based model was slightly better than the SVM-based model,and both were significantly better than the empirical MM(the Henderson and Pabis model),as evidenced by a comparison of the training root mean square error(RMSE),testing RMSE,training mean absolute error(MAE),testing MAE,training R2,and testing R2 of the Henderson and Pabis model,the BRBP neural network model,and the SVM-based *** results indicate that the MMs established by the two machine learning methods can better predict the moisture content changes in the paddy samples dried by LPSS.

关键词： paddy low-pressure superheated steam drying mathematical model characteristic

A Review of Atmospheric Electricity Research in 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

Advances in Atmospheric Sciences 2015年第2期32卷 169-191页

作者： QIE Xiushu zhang Yijun YUAN Tie zhang qilin zhang Tinglong ZHU Baoyou LU Weitao MA Ming YANG Jing ZHOU Yunjun FENG Guili Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of Sciences Laboratory of Lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences College of Atmospheric Science Lanzhou University College of Atmospheric Physics Nanjing University of Information Technology Laboratory for Climate Environment and Disasters of Western China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences School of Earth and Space Sciences University of Science and Technology of China College of Atmospheric Sciences Chengdu University of Information Technology Shandong Research Institute of Meteorology

The importance of atmospheric electricity research has been increasingly recognized in recent decades. Research on atmospheric electricity has been actively conducted since the 1980 s in China. Lightning physics and its effects, as important branches of atmospheric electricity, have received more attention because of their significance both in scientific research and lightning protection applications. This paper reviews atmospheric electricity research based primarily on ground-based field experiments at different regions in China in the last decade. The results described in this review include physics and effects of lightning, rocket-triggered lightning and its physical processes of discharge, thunderstorm electricity on the Tibetan Plateau and its surrounding areas, lightning activity associated with severe convective storms, the effect and response of lightning to climate change, numerical simulation of thunderstorm electrification and lightning discharge, lightning detection and location techniques, and transient luminous events above thunderstorms.

关键词： atmospheric electricity lightning physics rocket-triggered lightning thunderstorm charge structure lightning location techniques