检索结果-南通市图书馆

Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMS maglev train

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(Technological Sciences) 2024年第6期67卷 1957-1973页

作者： GAO Han SHI TingNa GAO XinMai LEI yanXiao yan Dong GUO Liyan yan yan College of Electrical Engineering Zhejiang UniversityHangzhou310027China Zhejiang University Advanced Electrical Equipment Innovation Center Hangzhou311107China State Key Laboratory of High-speed Maglev Transportation Technology Qingdao266100China CRRC Qingdao Sifang Co.Ltd. Qingdao266111China

The operating speed of the commercial electromagnetic suspension(EMS)maglev train has been over 430 km/h,making it the fastest means of land *** the increasing demands of people traveling,it is necessary to further improve the operating speed of maglev *** to examine whether the existing EMS system can meet the requirements of ultra-highspeed operation(more than 600 km/h),the electromagnetic characteristics of an EMS linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this ***,an electromagnetic field model of the EMS system under the square-wave voltage supply is established to investigate its electromagnetic performance,e.g.,the characteristics of phase current,the magnetic flux density,and the electromagnetic ***,the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated using the two-dimensional fast Fourier transform(2D-FFT)to reveal the mechanism of electromagnetic force ***,to address the issues of excessive armature current density and significant electromagnetic force ripple,the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic ***,the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric ***,the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA)based co-simulation.

关键词： ultra-high-speed maglev transportation electromagnetic suspension(EMS) linear motor electromagnetic force ripple suppression

Biomechanical behavior of grass roots at different gauge lengths

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第9期21卷 3201-3214页

作者： FU Jiangtao ZHOU Zhe GUO Hong ZHAO Jimei YU dongmei WU Jie HU Xiasong School of Civil Engineering and Architecture Shaanxi University of TechnologyHanzhong 723000China Crop Science postdoctoral research station Qinghai UniversityXining 810016China School of Geological Engineering Qinghai UniversityXining 810016China Qinghai institute of Salt Lakes Chinese Academy of SciencesXining 810008China Department of Geographical Science Shaanxi University of TechnologyHanzhong 723000China

Gauge length influences the biomechanical properties of herbaceous roots such as tensile resistance,tensile strength and Young’s ***,the extent to which and how these biomechanical properties of herbaceous roots are influenced remain *** better understand the behavior of roots in tension under different conditions and to illustrate these behaviors,uniaxial tensile tests were conducted on the Poa araratica roots as the gauge length increased from 20 mm to 80 ***,ANOVA was used to test the impact of the significant influences of gauge length on the biomechanical properties,nonlinear regression was applied to establish the variation in the biomechanical properties with gauge length to answer the question of the extent to which the biomechanical properties are influenced,and Weibull models were subsequently introduced to illustrate how the biomechanical properties are influenced by gauge *** results reveal that(1)the variation in biomechanical properties with root diameter depends on both the gauge length and the properties themselves;(2)the gauge length significantly impacts most of the biomechanical properties;(3)the tensile resistance,tensile strength,and tensile strain at cracks decrease as the gauge length increases,with values decreasing by 20%-300%,while Young’s modulus exhibits the opposite trend,with a corresponding increase of 30%;and(4)the Weibull distribution is suitable for describing the probability distribution of these biomechanical properties;the Weibull modulus for both tensile resistance and tensile strain at cracks linearly decrease with gauge length,whereas those for tensile strength and Young’s modulus exhibit the opposite *** tensile resistance,tensile strength,and tensile strain at the cracks linearly decrease with increasing gauge length,while the tensile strength and Young’s modulus linearly increase with increasing gauge length.

关键词： Biomechanical properties of roots Weibull distribution ANOVA Uniaxial tensile test Linear regression

Analysis of the Application Effect and Value of Dydrogesterone in The Treatment of Preeclampsia for Fetal Preservation

在线全文

学校读者我要写书评

暂无评论

Journal of Clinical and Nursing Research 2024年第4期8卷 143-148页

作者： dongmei Shen The People’s Hospital of Junan Linyi 276600Shandong ProvinceChina

Objective: To analyze the application effect and value of dydrogesterone in the fertility preservation treatment of preeclampsia. Methods: Forty cases of patients with preeclampsia admitted to our hospital between January 2023 and January 2024 were divided randomly into a control group and an observation group of 20 cases each. The control group applied progesterone to preserve the fetus, and the observation group applied dydrogesterone. The symptom relief time, hormone levels before and after treatment, as well as adverse drug reactions, and the effect of fetal preservation between the two groups were compared. Results: The time to relieve vaginal bleeding, abdominal pain. and lumbago in the observation group was shorter than that in the control group (P < 0.05). After treatment, the progesterone levels and incidence of adverse drug reactions in the observation group were lower than those in the control group (P < 0.05). The success rate of fertility preservation in the observation group was higher than that in the control group (P < 0.05). Conclusion: In the treatment of fetal preservation of preeclampsia, the application of dydrogesterone positively alleviated vaginal bleeding, abdominal pain, and lumbago, with mild adverse reactions and a good effect on fetal preservation.

关键词： Preeclampsia Fertility preservation treatment Dydrogesterone Application effect

Food odors alter behavioral responses and olfactory receptors expression in grass carp(Ctenopharyngodon idellus)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aquaculture and Fisheries 2024年第5期9卷 825-832页

作者： Ning Liu Xin Huang dongmei Zhu Suhua Guan Weimin Wang Han Liu College of Fisheries Key Lab of Agricultural Animal GeneticsBreeding and Reproduction of Ministry of EducationKey Laboratory of Freshwater Animal BreedingMinistry of Agriculture and Rural AffairsHuazhong Agricultural UniversityWuhan430070China Hubei Hongshan Laboratory Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic BeltMinistry of EducationWuhan430070China

Olfaction,the sense of smell,is crucial for animal survival,especially in localizing prey or ***,little is known about the fish behavioral responses to specific food odors and which olfactory receptor might be activated by the food ***,we examined the evolutionary relationships and classified the subfamilies of olfactory receptors(ORs),and conducted behavioral and gene expression analysis in grass carp(Ctenopharyngodon idellus).We identified 196 intact ORs in the grass carp genome and classified them into 8 subfamilies:β,δ,ε,η,γ,κ,θ,andζ.12 representative ORs(4β,4δ,and 4ε)were highly expressed in the olfactory epithelium(OE)of 24-month-old grass *** exploration found that grass carp showed different behaviors to different food odors at a series of ***,0.01μmol/L amino acid mixtures and 0.005×Hydrilla verticillata extracts strongly changed the preference index and swimming trajectories in 6-month-old grass *** addition,the two food odors stimulation differentially induced ORs expression in three tissues,especially strong in the olfactory bulb and ***,our results suggest that olfaction plays an important role in the regulation of fish feeding behavior and provide a basis for further studies on the function and specific recognition of olfactory receptors in fish.

关键词： Grass carp Olfactory receptors Behavioral responses Food odors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

艾滋病病人的病耻感现状调查

中国艾滋病性病 2016年第9期22卷 740-742页

作者：阎冬梅张秀军唐山市传染病医院河北唐山063000 迁安市疾病预防控制中心河北迁安064400

目的了解艾滋病(AIDS)病人的病耻感状况,为临床开展艾滋病的心理疏导,提高AIDS病人的生活质量以及采取合理的社会支持提供理论依据。方法采用社会影响量表,对来自唐山市传染病医院、唐山市和迁安市疾病预防控制中心的98名AIDS病人进行... 详细信息

目的了解艾滋病(AIDS)病人的病耻感状况,为临床开展艾滋病的心理疏导,提高AIDS病人的生活质量以及采取合理的社会支持提供理论依据。方法采用社会影响量表,对来自唐山市传染病医院、唐山市和迁安市疾病预防控制中心的98名AIDS病人进行问卷调查。结果 AIDS病人在社会排斥(t=3.232,P<0.01)和社会隔离(t=5.501,P<0.01)方面的得分明显高于国外常模,而在经济无保障(t=-3.176,P<0.01)方面的得分低于国外常模。不同性别、有无并发症和不同年龄的AIDS病人之间在病耻感上差异无统计学意义;不同婚姻状况的AIDS病人之间在内心羞辱(t=2.511,P<0.05)和社会隔离(t=2.329,P<0.05)方面差异有统计学意义。结论 AIDS病人存在较严重的病耻感,并且受婚姻状况影响。

关键词：艾滋病病人病耻感社会影响量表社会隔离

Thermal and mechanical behavior of casting copper alloy wheel during wheel and belt continuous casting process

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第1期21卷 82-90页

作者： Kun Gao yan Peng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

To investigate the thermal and mechanical behavior of casting wheel,a two-dimensional thermoelastic-plastic finite element model was used to predict the temperature,stress and distortion distribution of the casting wheel during the wheel and belt continuous casting *** effects of grinding thickness and casting speed on the thermal and mechanical behaviors of the center of the hot face of the casting wheel were discussed in *** each rotation,the casting wheel passes through four different spray *** results show that the temperature distribution of the casting wheel in different spray zones is similar,the temperature of the hot face is the highest and the temperature reaches the peak in the spray zoneⅢ.The stress and distortion depend on the temperature distribution,and the maximum stress and distortion of the hot face are 358.2 MPa and 1.82 mm,*** temperature at the center of the hot face decreases with increasing grinding thickness and increases with increasing casting speed.

关键词： casting wheel finite element model grinding thickness casting speed hot face spray zones

Numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第5期31卷 1117-1126页

作者： Kun Gao yan Peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated using the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

Topology Optimization of Two Fluid Heat Transfer Problems for Heat Exchanger Design

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第8期140卷 1949-1974页

作者： Kun yan Yunyu Wang Jun yan School of Chemical Engineering Dalian University of TechnologyDalian116024China Jianghuai Advanced Technology Center Hefei230000China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian116024China

Topology optimization of thermal-fluid coupling problems has received widespread *** article proposes a novel topology optimization method for laminar two-fluid heat exchanger *** proposed method utilizes an artificial density field to create two permeability interpolation functions that exhibit opposing trends,ensuring separation between the two fluid ***,a Gaussian function is employed to construct an interpolation function for the thermal conductivity ***,a computational program has been developed on the OpenFOAM platform for the topology optimization of two-fluid heat *** program leverages parallel computing,significantly reducing the time required for the topology optimization *** enhance computational speed and reduce the number of constraint conditions,we replaced the conventional pressure drop constraint condition in the optimization problem with a pressure inlet/outlet boundary *** 3D optimization results demonstrate the characteristic features of a surface structure,providing valuable guidance for designing heat exchangers that achieve high heat exchange efficiency while minimizing excessive pressure *** the same time,a new structure appears in large-scale topology optimization,which proves the effectiveness and stability of the topology optimization program written in this paper in large-scale calculation.

关键词： Topology optimization two fluid heat exchanger OpenFOAM large scale

Research on Modeling and Parameter Identification of Comprehensive Load Model of Distribution Network in Industrial Park

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 Electronics 2024年第1期33卷 264-273页

作者： Tingling WANG Xiaohe yan School of Electric Engineering North China University of Water Resources and Electric Power Wenzhou Polytechnic

With the rapid development of industrial parks, its load model research has become a hot spot. In order to study the load of power system in industrial park, based on the characteristics of the industrial park load, a comprehensive load admittance static model with full voltage range adaptability is considered, and a comprehensive load model of distribution network of the industrial park is established. A complete parameter identification of the model is carried out through chaos particle swarm optimization. The simulation results show that the model can effectively describe the load characteristics of the distribution network in industrial parks.

关键词： Chaos Adaptation models Analytical models Parameter estimation Induction motors Simulation Distribution networks