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Experimental study of anti-cavitation mechanism of valve lintel natural aeration of high head lock

Journal of Hydrodynamics 2020年第2期32卷 337-344页

作者： Xin Wang Ya-an hu jian-min Zhang Hydraulic Engineering Department Nanjing Hydraulic Research InstituteNanjing210029China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing210029China

To study the serious valve top gap cavitation of Datengxia high head single-lift ship lock,the 1:1 scale slice experiment is carried out,to truly reveal the gap flow characteristics,as well as the valve top gap cavitation characteristics and the anti-cavitation mechanism of natural *** kinds of cavitation,namely,the throat cavitation,the mainstream inner cavitation,and the valve plate cavitation,are determined and they are found to occur step-by-step in the gap section in the development of the *** to the anti-cavitation mechanism of the natural aeration,the pressure of the gap flow through the ventilation is increased,to avoid the mainstream inner cavitation and the valve plate cavitation,and to weaken the throat *** negative pressure zone in the gap section gradually extends with the development of the cavitation until the gap section is filled with a stable−10 m water *** the natural aeration measure is employed,the pressure in the gap section approximately reaches the−2 m water head,and the cavitation *** systematic tests reveal the quadratic polynomial relationship between the pressure in the gap and the ventilation per meter *** pressure,which corresponds to the maximum value of the ventilation at the beginning of the gap,approximately reaches the−2 m water head,and the pressure and the ventilation reach the equilibrium state *** the pressure in the gap increases when the valve is opened,the ventilation gradually decreases until the natural aeration *** gap section length for the high head valves has a great effect on the natural aeration and should be long enough to maintain the stable negative pressure in the gap,whereas the throat width has a minimal *** can be used for the anti-cavitation design of the high head lock valve.

关键词： High head lock valve top gap cavitation natural aeration slice experiment

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Study on dynamic response of multi-degree-of-freedom explosion vessel system under impact load

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Defence Technology（防务技术） 2020年第4期16卷 777-786页

作者： Yun-hao hu Wen-bin Gu jian-qing Liu Jing-lin Xu Xin Liu Yang-ming Han Zhen-xiong Wang College of Field Engineering Army Engineering University of PLANanjing 210007China Unit No.78102 of PLA Chengdu 610031China Unit No.31696 of PLA Jinzhou 121017China Research Institute of Chemical Defense Beijing 102205China

In order to study the dynamic response and calculate the axial dynamic coefficient of the monolayer cylindrical explosion vessel,the wall of vessel is simplified as a multi-degree-of-freedom(MDoF) undamped elastic foundation *** the coupled motion equation and using Duhamel's integrals,the solutions in generalized coordinates of the equations under exponentially decaying loads,square wave loads and triangular wave loads are *** solutions are consistent in form with the solutions of single-degree-of-freedom(SDoF) undamped forced vibration simplified *** on the model,equivalent MDoF design method(also called MDoF dynamic coefficient method) of cylindrical explosion vessel is *** traditional method can only predict the dynamic coefficient of torus portion around the explosion center,but this method can predict that of the vessel wall at any axial n dividing point *** is verified that the prediction accuracy of this model is greatly improved compared with the SDoF model by comparing the results of this model with SDoF model and numerical simulation in different working ***,the prediction accuracy decreases as the scaled distance decreases and approaches the end of the vessel,which is related to the accuracy of the empirical formula of the implosion load,the simplification of the explosion load direction,the boundary conditions,and the loading time difference.

关键词： Explosion vessel Dynamic response Vibration analysis Dynamic coefficient Load feature

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Highly Transparent and Adhesive Poly(vinylidene difluoride)Films for Self-Powered Piezoelectric Touch Sensors

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Chinese Journal of Polymer Science 2022年第7期40卷 726-737页

作者： qing-qing Li Guang-Kuo Wang Zi-Xu Liang Zhi-Jun hu School of Optoelectronic Science and Engineering&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou215006China Center for Soft Condensed Matter Physics and Interdisciplinary Research Soochow UniversitySuzhou215006China Soochow University Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province&Key Lab of Modern Optical Technologies of Education Ministry of ChinaSuzhou215006China

With the rapid development of internet of things,self-powered touch sensors made of piezoelectric fluorinated polymers have attracted significant interest because they can constantly convert mechanical energy into electrical energy without external power ***,it is still challenging to fabricate fluorinated polymer films with good adhesion and high output performance with a large-scale and low-cost method while maintaining high transparency,which are extremely important for simultaneous optical detection and electromechanical *** this work,we demonstrate that the incorporation of a molecular ferroelectric-dabcoHReO_(4)(DH)into poly(vinylidene difluoride)(PVDF)solution enables high-throughput and low-temperature processing of flexible and transparent piezoelectric films by scalable processing *** effects of multiaxial DH are ***,DH can trigger the phase transition of PVDF fromα-toβ-phase and realize the orderly orientation of PVDF,which guarantees higher piezoelectric performance without any additional electrical poling ***,the hydrophilic nature of DH can improve the adhesion properties of PVDF,which in turn improve the stability and durability of the *** optimizing the fabrication processes,the transmittance of the piezoelectric touch sensors based on PVDF films and Ag nanowires coated poly(ethylene terephthalate)electrodes can be higher than 94%.The piezoelectric voltage constant g;of the transparent films can reach to 1.2 V·m·N;,which is at least three times higher than the commercially available PVDF films obtained by *** results indicate that the flexible piezoelectric sensors have potential applications in transparent electronic devices for mechanical sensing and energy harvesting.

关键词： PVDF Transparent Adhesive Large scale Piezoelectric sensor

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Enhanced breakdown strength of BaTiO_(3)-based multilayer ceramic capacitor by structural optimization

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Rare Metals 2023年第8期42卷 2552-2561页

作者： Qian Liu hua Hao qing-hu Guo Zhong-hui Shen jian Wang Ming-He Cao Zhong-hua Yao Han-Xing Liu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Material Science and EngineeringWuhan University of TechnologyWuhan 430070China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan 528220China Sanya Science and Education Innovation Park of Wuhan University of Technology Sanya 572000China International School of Material Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center of Smart Materials and DevicesWuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Material Science and EngineeringWuhan University of TechnologyWuhan 430070China

0.5 wt%Nb_(2)O_(5)doped 0.12BiAlO_(3)-0.88BaTiO_(3)(12BA5N)multilayer ceramic capacitor(MLCC-1)was prepared,which satisfied EIA X7R specification(where X is the minimum temperature,R is the percentage of capacitance variation limit)at 1 *** distribution of internal electric field under breakdown voltage was simulated by finite element method(FEM),indicating that the electric field strength increased significantly at the terminal of internal *** areas may become the headstream of breakdown for MLCC-1 due to the shape *** order to improve the breakdown performance of MLCC-1,it was optimized by 12BA5N+2G green sheets(prepared by 12BA5N ceramic powder with 2 wt%B-Al-Si glass additive),then MLCC-2 was obtained which satisfied EIA X8R *** BDS rose from 20 to29.4 kV·mm^(-1),and the electric field distribution of dielectric layer was also analyzed by ***,it was also found that the grain size and the dielectric constants of"core"and"shell"parts for the 12BA5N+2G dielectric layer both contributed to the enhanced BDS of MLCC-2according to the simulation results from FEM.

关键词： Multilayer ceramic capacitor(MLCC) Breakdown strength(BDS) Simulation Grain size Dielectric constant

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Design,fabrication,and testing of an X-band 9-MeV standing-wave electron linear accelerator

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Nuclear Science and Techniques 2023年第7期34卷 219-230页

作者： jian Gao Hao Zha Jia-Ru Shi Qiang Gao Xian-Cai Lin Fang-Jun hu qing-Zhu Li huai-Bi Chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China

In this study,an X-band standing-wave biperiodic linear accelerator was developed for medical radiotherapy that can accel-erate electrons to 9 MeV using a 2.4-MW *** structure works atπ/2 mode and adopts magnetic coupling between cavities,generating the appropriate adjacent mode separation of 10 *** accelerator is less than 600-mm long and constitutes four bunching cells and 29 normal *** optimizations,full-scale radiofrequency(RF)simulations,and beam dynamics calculations were *** accelerator was fabricated and examined using a low-power RF *** cold test results showed a good agreement with the simulation and actual measurement *** the high-power RF test,the output beam current,energy spectrum,capture ratio,and spot size at the accelerator exit were *** the input power of 2.4 MW,the pulse current was 100 mA,and the output spot root-mean-square radius was approximately 0.5 *** output kinetic energy was 9.04 MeV with the spectral FWHM of 3.5%,demonstrating the good performance of this accelerator.

关键词： Standing-wave accelerating structure RF analysis Thermal DC gun Low-power RF test High-power experiment

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Analysis and optimization of performance parameters of the^(220)Rn chamber in flow-field mode using computational fluid dynamics method

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Nuclear Science and Techniques 2024年第10期35卷 70-85页

作者： Shao-hua hu Yong-Jun Ye Zheng-Zhong He De-Tao Xiao Xiang-Yu Xu jian-Kai Wang qing-Zhi Zhou School of Nuclear Science and Technology University of South ChinaHengyang 421001China School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China

The impact of the radiation dose produced by^(222)Rn/^(220)Rn and its progeny on human health has garnered increasing interest in the nuclear research *** establishment of robust,regulatory,and competent^(220)Rn chambers is crucial for accurately measuring radioactivity ***,studying the uniformity of the^(220)Rn progeny through experimental methods is challenging,because measuring the concentration of^(220)Rn and its progeny in multiple spatial locations simultaneously and in real time using experimental methods is ***,achieving precise control of the concentration of^(220)Rn and its progeny as well as the reliable sampling of the progeny pose significant *** solve this problem,this study uses computational fluid dynamics to obtain the flow-field data of the^(220)Rn chamber under different wind speeds and progenyreplenishment *** analysis of the concentration distribution of the progeny and quantitative analysis of the progeny concentration and uniformity of the progeny concentration are *** research findings indicated that the progeny concentration level is primarily influenced by wind speed and the progeny-complement *** speed also plays a crucial role in determining progeny concentration uniformity,whereas the progeny-complement rate has minimal impact on *** ensure the accuracy of^(220)Rn progeny concentration sampling,we propose a methodology for selecting an appropriate sampling area based on varying progeny *** study holds immense importance for enhancing the regulation and measurement standards of^(220)Rn and its progeny.

关键词： Thoron Progeny Regulatory CFD simulation

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Artificial neural network-based method for discriminating Compton scattering events in high-purity germaniumγ-ray spectrometer

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Nuclear Science and Techniques 2024年第2期35卷 64-84页

作者： Chun-Di Fan Guo-Qiang Zeng Hao-Wen Deng Lei Yan jian Yang Chuan-Hao hu Song qing Yang Hou College of Nuclear Technology and Automation Engineering Chengdu University of TechnologyChengdu 610059China

To detect radioactive substances with low activity levels,an anticoincidence detector and a high-purity germanium(HPGe)detector are typically used simultaneously to suppress Compton scattering background,thereby resulting in an extremely low detection limit and improving the measurement ***,the complex and expensive hardware required does not facilitate the application or promotion of this ***,a method is proposed in this study to discriminate the digital waveform of pulse signals output using an HPGe detector,whereby Compton scattering background is suppressed and a low minimum detectable activity(MDA)is achieved without using an expensive and complex anticoincidence detector and *** electric-field-strength and energy-deposition distributions of the detector are simulated to determine the relationship between pulse shape and energy-deposition location,as well as the characteristics of energy-deposition distributions for fulland partial-energy deposition *** relationship is used to develop a pulse-shape-discrimination algorithm based on an artificial neural network for pulse-feature *** accurately determine the relationship between the deposited energy of gamma(γ)rays in the detector and the deposition location,we extract four shape parameters from the pulse signals output by the *** learning is used to input the four shape parameters into the ***,the pulse signals are identified and classified to discriminate between partial-and full-energy deposition *** partial-energy deposition events are removed to suppress Compton *** proposed method effectively decreases the MDA of an HPGeγ-energy dispersive *** results show that the Compton suppression factors for energy spectra obtained from measurements on ^(152)Eu,^(137)Cs,and ^(60)Co radioactive sources are 1.13(344 keV),1.11(662 keV),and 1.08(1332 keV),respectively,and that the corresponding MDAs are 1.4%,5.

关键词： High-purity germaniumγ-ray spectrometer Pulse-shape discrimination Compton scattering Artificial neural network Minimum detectable activity

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Interface energetics and engineering of organic heterostructures in organic photovoltaic cells

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Science China Chemistry 2016年第4期59卷 422-435页

作者： Yan-qing Li Qian-Kun Wang qing-Dong Ou jian-Xin Tang Institute of Functional Nano & Soft Materials Collaborative Innovation Center of Suzhou Nano Science and TechnologyJiangsu Key Laboratory for Carbon-based Functional Materials & Devices Soochow University

The reliable information about interface energetics of organic materials, especially the energy level alignment at organic heterostructures is of pronounced importance for unraveling the photon harvesting and charge separation process in organic photovoltaic(OPV) cells. This article provides an overview of interface energetics at typical planar and mixed donor-acceptor heterostructures, perovskite/organic hybrid interfaces, and their contact interfaces with charge collection layers. The substrate effect on energy level offsets at organic heterostructures and the processes that control and limit the OPV operation are presented. Recent efforts on interface engineering with electrical doping are also discussed.

关键词： organic photovoltaic cell organic heterostructure energy level alignment substrate effect interface engineering

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A major pathway for carbon and nitrogen losses-Gas emissions during storage of solid pig manure in China

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Journal of Integrative Agriculture 2019年第1期18卷 190-200页

作者： SHAN Nan LI hu LI jian-zheng Ee Ling Ng MA Yan WANG Li-gang CHEN qing College of Resources and Environmental Sciences China Agricultural University Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Faculty of Veterinary and Agricultural Sciences University of Melbourne

This study investigated the carbon(C) and nitrogen(N) gas emissions(N_2O,NH_3,CO_2 and CH_4) from solid pig manure management in *** emissions were quantified from static piles over 60 days during summer in China's Yangtze River Basin,using Drager-Tube and static chamber-gas chromatography *** emissions of NH_3 and N_2 O were observed at the early stage of storage,but high emission of CH_4 occured later during ***,62% of the total C in the original pile was lost; CO_2 and CH_4 emissions accounted for 57 and 0.2% of C lost *** the same time,41% of the total N in the original pile was lost; NH_3 and N_2 O emissions accounted for 15 and 0.3% of N lost *** volatilization of NH_3 during storage in summer was 4.56 g NH_3 per kg dry *** total greenhouse gas(GHG) emissions during storage accounted for 67.93 g CO_2 equivalent per kg dry weight; N_2 O and CH_4 contributed to 46 and 55% of total GHG emissions *** China's major role in pig production,further attention should given to pig manure management to mitigate its contribution to atmospheric pollution.

关键词： storage static pile ammonia nitrogen and carbon emissions greenhouse gas emission pig manure management

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Effect of ultraviolet mutagenesis on heterotrophic strain mutation and bioleaching of low grade copper ore

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Journal of Central South University 2017年第10期24卷 2245-2252页

作者： WU Ai-xiang hu Kai-jian WANG Hong-jiang ZHANG Ai-qing YANG Ying School of Civil and Environmental Engineering University of Science and Technology Beijing School of Resources and Environmental Engineering Jiangxi University of Science and Technology

The effect of ultraviolet mutagenesis on a heterotrophic strain(Providencia JAT-1) mutation was studied and bioleaching of low grade copper ore with mutant bacteria was investigated. The results show that the activity of bacteria was improved after ultraviolet mutagenesis; the best irradiation time was 120 s. Compared to the original bacteria, the cells density of mutant bacteria at stationary phase increased by 26% and ammonia produced by mutant bacteria increased by 12%. Higher activity of bacteria leads to a higher copper extraction rate. The bioleaching performance of Providencia JAT-1 was improved after UV mutagenesis. The copper extraction rate with mutant bacteria increased by 10.6% compared to the original bacteria. The ore surface was corroded and the fine particles were absent after bioleaching. Free copper oxide and copper silicates could be leached out easily by using JAT-1; a small part of the copper sulfide can also be leached out. Bioleaching using JAT-1 is more effective than ammonia leaching and copper extraction rate with mutant bacteria was 21.1% higher than that by ammonia leaching under the same condition.

关键词： ultraviolet mutagenesis bioleaching heterotrophic strain ammonia low grade copper ore

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