检索结果-南通市图书馆

A Linear Perturbed Palais-Smale Condition for Lower Semicontinuous Functions on Banach Spaces

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2008年第11期24卷 1853-1860页

作者： Li xing cheng Xiao Yan LIU Mai Fang ZUO Department of Mathematics Xiamen University Xiamen 361005 P. R. China

This paper introduces a notion of linear perturbed Palais-Smale condition for real-valued functions on Banach spaces. In terms of strongly exposed points, it presents a characterization which guarantees linear perturbed Palais-Smale condition holds for lower semicontinuous functions with bounded effective domains defined on a Banach space with the Radon-Nikody＇m property; and gives an example showing that linear perturbed P-S condition is strictly weaker than the P-S condition.

关键词： Palais-Smale condition variational question perturbed optimization Radon-Nikody'm property Banach space

Computational study of fluid-borne noise in vertical inline pump

在线全文

学校读者我要写书评

暂无评论

排灌机械工程学报 2019年第2期37卷 93-99页

作者： CHRISTOPHER Stephen YUAN Shouqi PEI Ji cheng xing Department of Mechanical Engineering Vel Tech Rangarajan Dr.Sagunthala R & D Institute of Science and Technology National Research Center of Pumps Jiangsu University

The objective of present work is to find out the sources of fluid-borne noise in vertical inline pump for various flow rates. The three-dimensional unsteady Reynolds Average Navier Stokes equation was solved using computational fluid dynamics code to predict the acoustic distribution. The pump chosen for study was of low specific speed and the experimental performance characteristic was very well matched with computational head developed. PROUDMAN sound power contour analysis showed the critical zone of noise in inlet pipe,impeller,and volute. Based on this,the variations of acoustic power were depicted over the cross section of inlet pipe,along the mean streamline of inlet pipe,as well along the volute circumference. The result concludes that the predominant flow noise is at tongue region and followed by noise generated due to turbulence in inlet pipe which occurs by the sudden variation in flow passage as well it depends on the operating condition of pump. The frequency analysis gives a glimpse of understanding about the broadband noise distribution due to flow phenomenon over a frequency range.

关键词： vertical inline pump fluid-borne noise return flow inlet pipe PROUDMAN

Microstructure and mechanical properties of WC-Co-based cemented carbide with bimodal WC grain size distribution

在线全文

学校读者我要写书评

暂无评论

稀有金属:英文版 2023年第8期42卷 2809-2815页

作者： Rui-Jun Cao Chen-Guang Lin xing-cheng Xie Zhong-Kun Lin Powder Metallurgy and Special Materials Department General Research Institute for Nonferrous MetalsBeijing 100088China

In order to improve the wear resistance of coarse-grained WC-Co cemented carbides,the fine WC powder were used to reinforce the metallic *** WC-Co-based cemented carbides having bimodal WC grain size distributions were synthesized by liquid phase *** comparison,the cemented carbides having unimodal WC grain size distributions were *** microstructure,hardness,fracture toughness and wear resistance of these cemented carbides were *** results show that adding fine WC powder is an effective method to improve the wear resistance of coarsegrained WC-Co cemented *** WC size,mean free path and fracture toughness decrease with the addition of fine WC powder,while the hardness exhibits an opposite *** impact-wear coefficient of bimodal distribution cemented carbides is noticeably lower than that of the unimodal one with the same hardness,which means that the cemented carbides with bimodal grain structure have better combination of hardness and impact-abrasive wear *** impact-abrasive wear mechanism of the bimodal cemented carbides is that the fine WC grains prevent abrasive wear and the coarse WC grains prevent impact wear.

关键词： WC-Co cemented carbide Impact wearing Bimodal distribution Hardness Mean free path

Study on the Relationship Between Sex Differentiation and Ethylene in Ramie

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2009年第4期8卷 418-423页

作者： xing Hu-cheng SHE Wei LUO Zhong-qin QIN Zhan-jun JIE Yu-cheng Ramie Research Institute Hunan Agricultural University Changsha 410128 P.R.China Institute of Bast Fiber Crops Chinese Academy of Agricultural Sciences Changsha 410205 P.R. China

To explore the role of ethylene in sexual determination in ramie, the ethylene release rates in ramie stem apex of different sex, bud of the same node in female and hermaphrodite ramie in the second crop, and single inflorescence of different sex in hermaphrodite ramie were measured by gas chromatography. Effects of two ethylene inhibitors on sex expression in ramie were investigated. The ethylene release rate of stem apex was higher in the second crop or female ramie than that in the third crop or hermaphrodite ramie during growth. Although ethylene release rates between lower nodes and higher nodes were little different, it was lower in the middle nodes in hermaphrodite ramie. The ethylene release rates were higher in the higher nodes of female ramie at the second crop. At the third crop, the ethylene release rates were higher in lower nodes, lower in middle nodes and then highest in higher nodes in female ramie. However, an opposite ethylene release pattern was observed in hermaphrodite ramie. The ethylene release rate was higher in female flower than male flower and mixed inflorescence in hermaphrodite ramie. The male flower could be distinctly induced by AVG （aminooethoxyvinylglycine）. The node of the first male flower, percentage of female flowers and ratio of female flowers to male in ramie were evidently depressed by AVG in contrast to water. The percentage of mixed male and female flowers was also increased and the percentage of female flower decreased by spraying AgNO3. There was a close relationship between sexual differentiation and ethylene release rate in ramie. The female ramie could be induced by high ethylene release rate. The female flower could be inhibited by AVG and AgNO3. AVG at a concentration of 300 mg L^-1 was most effective.

关键词： ramie [Boehmeria nivea (L.) Gaud] sex ethylene

前庭康复训练结合抗焦虑治疗对良性阵发性位置性眩晕患者复发情况及前庭功能和焦虑抑郁状态的影响

在线全文

学校读者我要写书评

暂无评论

医药论坛杂志 2024年第3期45卷 297-300页

作者：徐静陈广理李兴程郑州大学第一附属医院耳科郑州450052

目的研究良性阵发性位置性眩晕(benign paroxysmal positional vertigo, BPPV)患者联合采用前庭康复训练和抗焦虑治疗的临床效果。方法通过双盲法分组标准对郑州大学第一附属医院耳科2021年11月—2023年3月72例BPPV患者进行分组,分为... 详细信息

目的研究良性阵发性位置性眩晕(benign paroxysmal positional vertigo, BPPV)患者联合采用前庭康复训练和抗焦虑治疗的临床效果。方法通过双盲法分组标准对郑州大学第一附属医院耳科2021年11月—2023年3月72例BPPV患者进行分组,分为常规组和治疗组,每组各36例。常规组予常规前庭康复训练治疗,治疗组予前庭康复训练配合抗焦虑治疗。对两组临床效果、焦虑与抑郁状态进行对比,并评估前庭功能,调查复发情况。结果治疗组总有效率97.22%,高于常规组的80.56%,差异有统计学意义(P<0.05);治疗组治疗后焦虑评定量表(SAS)及抑郁评定量表(SDS)评分为(48.67±1.21)分和(51.37±1.08)分,均低于治疗前和常规组,差异均有统计学意义(P<0.05);治疗组治疗后前庭症状指数(VSI)及日常活动前庭功能障碍等级量表(VADL)评分为(16.49±2.16)分和(30.93±3.36)分,均低于治疗前和常规组,BBS评分高于治疗前和常规组,差异均有统计学意义(P<0.05);治疗组复发率(2.78%)低于常规组(16.67%),差异有统计学意义(P<0.05)。结论对BPPV患者采用前庭康复训练配合抗焦虑治疗效果确切,能改善心理状态与前庭功能,控制复发率,适合进一步推广。

关键词：抗焦虑治疗良性阵发性位置性眩晕前庭功能前庭康复训练

Distillation of GHZ State from Multiple Copies of Arbitrary W-Class State

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第6期49卷 1502-1504页

作者： WU Chun-Wang CHEN Ping-xing LI cheng-Zu Department of Applied Physics National University of Defense Technology Changsha 410073 China

W. Dur et al. have shown that it is impossible to obtain a GHZ state from one copy of arbitrary W-class state via local operations and classical communication （LOCC） [W. Dur, G. Vidal, and J.I. Cirac, Phys. Rev. A 62 （2000） 062314]. In our paper, the more general case is carefully investigated. We first show that, with a supply of two copies of arbitrary W-class state, we can always construct an explicit procedure to distill a GHZ state with a nonzero probability. Then based on this result, a simple procedure for distilling GHZ state from n copies of arbitrary W-class state is presented. Finally, we briefly discuss the applications.

关键词： distillation GHZ state W-class state

Simple Procedure for Entanglement Transformation of Bipartite Pure States

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第3期49卷 652-654页

作者： WU Chun-Wang CHEN Ping-xing LI cheng-Zu Department of Applied Physics National University of Defense Technology Changsha 410073 China

An explicit procedure for transforming one bipartite entangled state into another via local operations and classical communication （LOCC） is presented. Our procedure is much simper than the previous ones in the sense that, it only involves two steps and the explicit expression of local general measurement used in the procedure can be obtained by solving a set of linear equations. Furthermore, this procedure is still applicable in high dimensional case.

关键词： procedure entanglement transformation bipartite pure states linear equations

Microscopic characterization of semi-solid aluminium alloys

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第3期17卷 290-296页

作者： Ya-lin Lu Miao-quan Li xing-cheng Li Xiao-ping Li School of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072 China School of Materials Engineering Jiangsu Teachers University of Technology Changzhou 213000 China

The microstructural evolution and element distribution of the Al-4Cu-Mg alloy during semi-solid compression were investigated, and the precipitate behavior and dislocation morphology were discussed. The experimental results show that the microstructure, the number of CuAl2 （θ phase） precipitates, and the dislocation density of the Al-4Cu-Mg alloy depend apparently on the process parameters. More segregation of Cu at the grain boundary happens with an increase of deformatinn temperature and a decrease of strain rate, leading to an increase in the number of θ phase. With an increase of height reduction, Cu segregation at the grain boundary decreases gradually. Moreover, unique dislocation morphologies including helical dislocations and dislocation loops appear at different process parameters and evolve to reduce the stored energy.

关键词： aluminum alloys semi-solid state microstructural evolution dislocation

Large eddy simulation of cloud cavitation and wake vortex cavitation around a trailing-truncated hydrofoil

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2022年第5期34卷 893-903页

作者： Ting-yun Yin Giorgio Pavesi Ji Pei Shou-qi Yuan xing-cheng Gan National Research Center of Pumps Jiangsu UniversityZhenjiang212013China Department of Industrial Engineering University of PaduaPaduaItaly Turbomachinery and Energy Systems Group University of PaduaPaduaItaly

The cavitation has received considerable attention for decades because of its negative influence on the performance and the safety of the hydraulic *** this study,a large eddy simulation is carried out to numerically investigate the unsteady cavitating flow around a trailing-truncated NACA 0009 hydrofoil for determining the underlying physical *** types of cavitation morphologies are identified:The large-scale bubble cluster and the von Kármán vortex cavity,named as the cloud cavitation and the wake vortex cavitation,*** is shown that the velocity profiles obtained over the hydrofoil suction surface are in good agreement with the experimental data,indicating the accuracy of the current *** dynamic evolution of the sheet/cloud cavity is also well reproduced,covering the sheet cavity breakup,the sheet/cloud transformation,and the collapse of the cloudy bubble *** wake-vortex cavitation is caused by the blunt geometry at the hydrofoil trailing edge,where pairs of vortex cavities are *** the cloud and vortex cavities significantly affect the lift oscillation,which makes it difficult to decompose the *** fundamental shedding mechanisms of the wake vortex cavitation are discussed based on the finite-time Lyapunov exponent ***,the suction-side bubble grows and squeezes the giant pressure bubble away from the trailing *** the pressure bubble detaches,a new counterclockwise vortex or a new bubble appears at the pressure side,thus lifting the ridge towards the suction trailing edge and generating a strong vortex eye that pinches off the trailing portion of the suction-side bubble.

关键词： Cloud cavitation wake vortex cavitation trailing-truncated hydrofoil large eddy simulation