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UNSTEADY FLOW ANALYSIS AND EXPERIMENTAL INVESTIGATION OF AXIAL-FLOW PUMP

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Journal of Hydrodynamics 2010年第1期22卷 35-43页

作者： ZHANG De-sheng shi wei-dong CHEN Bin GUAN Xing-fan Technical and Research Center of Fluid Machinery Engineering Jiangsu University Zhenjiang 212013 China

The three-dimensional unsteady turbulent flow in axial-flow pumps was simulated based on Navier-Stoke solver embedded with k - ε RNG turbulence model and SIMPLEC algorithm. Numerical results show that the unsteady prediction results are more accurate than the steady results, and the maximal error of unsteady prediction is only 4.54%. The time-domain spectrums show that the static pressure fluctuation curves at the inlet and outlet of the rotor and the outlet of the stator are periodic, and all have four peaks and four valleys. The pressure fluctuation amplitude increases from the hub to the tip at the inlet and outlet of the rotor, but decreases at the outlet of the stator. The pressure fluctuation amplitude is the greatest at the inlet of the rotor, and the average amplitude decreases sharply from the inlet to the outlet. The frequency spectrums obtained by Fast Fourier Transform （FFT） show that the dominant frequency is approximately equal to the blade passing frequency. The static pressure on the pressure side of hydrofoil on different stream surfaces remains almost consistent, and increases gradually from the blade inlet to the exit on the suction side at different time steps. The axial velocity distribution is periodic and is affected by the stator blade number at the rotor exit. The experimental results show that the flow is almost axial and the pre-rotation is very small at the rotor inlet under the conditions of 0.8 QN -1.2 QN Due to the clearance leakage, the pressure, circulation and meridional velocity at the rotor outlet all decrease near the hub leakage and tip clearance regions.

关键词： axial-flow pump unsteady flow pressure fluctuation high efficiency flow field measurement

Influence of heat treatment on microstructure and mechanical properties of Al/Al-Cu graded materials

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Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 118-124页

作者： Qian CONG Fumin XU Yi TAN Xiaolei shi wei dong Jiayan LI Junshan ZHANG School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

Five-layered Al/Al-Cu functionally graded material （FGM） was prepared by powder metallurgy technology, and the subsequent heat treatment was carried out for the graded material. The microstructures and distribution of Cu element under pressure sintering （F）, solution treatment （T4） and artificial aging treatment （T6） were investigated, and the Vickers hardness and flexural properties of different states were tested. The results showed that sintered compact with dense structure and compositional continuous change was obtained. The second-phase CuAl 2 was dispersively distributed along grain boundary of Al matrix. After solution treatment at 503 C for 3 h, CuAl 2 phase obviously decreased and dissolved into the Al matrix, and the flexural strength was thereupon enhanced to 228.5 MPa. With the subsequent aging treatment at 150 C for 15 h, the majority of flake shaped precipitates θ phases were uniformly distributed in the matrix. And the distribution of Cu element became gradual continuous compared to sintered compact. Meanwhile, the flexural strength increased further, which accompanied with the decline of plasticity.

关键词： Al/Al-Cu graded material Solution treatment Artificial aging Mechanical properties

Vertical Price Transmission in the China's Layer Industry Chain:an Application of FDL Approach

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Agricultural Sciences in China 2011年第11期10卷 1812-1823页

作者： XU shi-wei dong Xiao-xia LI Zhe-min LI Gan-qiong Key Laboratory of Digital Agricultural Early-Warning Technology Ministry of Agriculture~Agricultural Information Institute ChineseAcademy of Agricultural Sciences Beijing 100081 P.R.China

This paper examines the vertical price relationship between upstream and downstream products in China＇s layer industry chain by estimating elasticity coefficients of the price transmission. We use cointegration tests, error correction models and finite distributed lag models to analyze vertical price shifts between corn, layer feed, egg-laying chicken and egg prices. With monthly data from 1994 to 2010, our results show that various prices in China＇s layer industry chain are well integrated. In addition, our results indicate that both long-run and short-run price relationships between upstream and downstream products in layer industry chain exist and the long-run equilibrium, to a certain extent, may eliminate the short-run dynamics price deviation. We also found that the influence of corn and feed prices on egg prices is still more remarkable than egg-laying chicken prices. Our findings imply that governments should pay more attention to corn and layer feed prices in order to stabilize egg prices under the conditions of market integration.

关键词： finite distributed lag model vertical price transmission layer industry chain China

Experimental study of flow field in interference area between impeller and guide vane of axial flow pump

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Journal of Hydrodynamics 2014年第6期26卷 894-901页

作者：张华施卫东陈斌张启华曹卫东 Research Center of Fluid Machinery Engineering and Technology Jiangsu University Research Institute of Chemical Machinery Hefei University of Technology

Axial flow pump is a kind of typical pumps with rotor-stator interaction, thus the measurement of the flow field between impeller and guide vane would facilitate the study of the internal rotor-stator interaction mechanism. Through a structural modification of a traditional axial flow pump, the requirements of particle image velocimetry（PIV） measurement are met. Under the condition of opt.0.8Q, the axial vortex is identified between impeller hub and guide vane hub, which is developed into the main flow and to affect the movement when the relative positions of impeller and guide vane at different flow rates are the same. Besides, the development and the dissipation of the tip leakage and the passage vortex in impeller passages are mainly responsible for the difference of the flow field close to the outer rim. As the flow rate decreases, the distribution of the meridional velocities at the impeller outlet becomes more non-uniform and the radial velocity component keeps increasing. The PIV measurement results under the condition of opt.1.0Q indicate that the flow separation and the trailing vortex at the trailing edge of a blade are likely to result in a velocity sudden change in this area, which would dramatically destroy the continuity of the flow field. Moreover, the radial direction of the flow between impeller and guide vane on the measurement plane does not always point from hub to rim. For a certain position, the direction is just from rim to hub, as is affected by the location of the intersection line of the shooting section and the impeller blade on the impeller as well as the angle between the intersection line and the rotating shaft.

关键词： axial flow pump tip leakage passage vortex radial velocity axial velocity

Preventive and therapeutic effects of penehyclidine hydrochloride on morphine-induced increased bladder pressure, urinary bladder sphincter pressure and histological damage in rabbits

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Chinese Medical Journal 2012年第6期125卷 1141-1146页

作者： shi wei-dong WANG wei-wei CUI Xiao-guang PAN Peng ZHANG Bing LI Wen-zhi Department of Anesthesiology Second Affiliated Hospital of Harbin Medical UniversityAnesthesiology and Critical Medicine Major Laboratory of Heilongjiang ProvinceHarbinHeilongjiang 150081China

Background Morphine has become the preferred drug for analgesia. However, analgesic doses of morphine can result in urinary retention, which is an intractable problem in clinical practice. Though bladder catheterization is one available therapeutic option, data supporting the technique＇s effectiveness are controversial. As a novel anti-cholinergic medicine developed in China, penehyclidine hydrochloride （PHC） exhibits greater selectivity for M3/M1 receptors than M2 receptors. Therefore, this study aimed to determine the efficacy of PHC in treating urinary retention. Methods Thirty-two healthy male New Zealand white rabbits were randomly divided in four groups （n=8 each） as follows： control group （C group）, PHC low-dose group （PL group, 0.01 mg/kg of PHC intramuscularly）, PHC middle-dose group （PM group, 0.02 mg/kg of PHC intramuscularly）, and PHC high-dose group （PH group, 0.05 mg/kg of PHC intramuscularly）. All rabbits were injected intravenously with morphine （1 mg/kg） to induce urinary retention and different doses of PHC were injected intramuscularly in the PL, PM and PH groups. In the C group, 1 ml saline was administered instead of PHC. The bladder pressure and the bladder sphincter pressure were recorded at different time points. The plasma concentration of PHC was measured at different time points with high performance liquid chromatography. Arterial blood pressure and heart rate （HR） were recorded at different time points. Results Bladder pressure and urinary bladder sphincter pressure rose significantly from 30 minutes after morphine administration until the end of the experiment. PHC markedly attenuated the elevations in pressure induced by morphine. Morphometric analysis also revealed histological damage, erythrocytes and ruptures of the microcirculation in regions of the submucosa and smooth muscle. Morphometric damage was ameliorated with PHC but not with saline. Hemodynamic data （mean arterial pressure （MAP） and HR） did not differ between groups over

关键词： penehyclidine hydrochloride urinary retention rabbits

Low-temperature chlorination roasting technology for the simultaneous recovery of valuable metals from spent LiCoO_(2)cathode material

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 80-91页

作者： Junjie shi Changle Hou Jingjing dong dong Chen Jianzhong Li Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China

With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular *** study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode *** activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded *** conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,*** of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and ***,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure *** technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.

关键词： spent lithium-ion battery thermodynamics chlorination roasting kinetics circular economy

Breakdown voltage enhancement in GaN channel and AlGaN channel HEMTs using large gate metal height

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Chinese Physics B 2020年第2期29卷 420-424页

作者： Zhong-Xu Wang Lin Du Jun-wei Liu Ying Wang Yun Jiang Si-wei Ji shi-wei dong wei-wei Chen Xiao-Hong Tan Jin-Long Li Xiao-Jun Li Sheng-Lei Zhao Jin-Cheng Zhang Yue Hao Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi'an 710071China Shanghai Precision Metrology and Testing Research Institute Shanghai 201109China China Academy of Space Technology(Xi'an) Xi'an 710000China Sichuan Institute of Solid-State Circuits CETCChongqing 400060China

A large gate metal height technique is proposed to enhance breakdown voltage in GaN channel and AlGaN channel high-electron-mobility-transistors(HEMTs).For GaN channel HEMTs with gate-drain spacing LGD=2.5μm,the breakdown voltage VBR increases from 518 V to 582 V by increasing gate metal height h from 0.2μm to 0.4μ*** GaN channel HEMTs with LGD=7μm,VBR increases from 953 V to 1310 V by increasing h from 0.8μm to 1.6μ*** breakdown voltage enhancement results from the increase of the gate sidewall capacitance and depletion region *** Al0.4Ga0.6N channel HEMT with LGD=7μm,VBR increases from 1535 V to 1763 V by increasing h from 0.8μm to 1.6μm,resulting in a high average breakdown electric field of 2.51 MV/*** and analysis indicate that the high gate metal height is an effective method to enhance breakdown voltage in GaN-based HEMTs,and this method can be utilized in all the lateral semiconductor devices.

关键词： GaN channel HEMTs AlGaN channel HEMTs breakdown voltage gate metal height

铌酸锰-还原氧化石墨烯复合光催化剂的构建以及可见光下降解亚甲基蓝（英文）

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无机化学学报 2017年第3期33卷 493-500页

作者：顾巍严铭孙林施伟东江苏大学化学化工学院镇江212013 江苏大学材料科学与工程学院镇江212013

通过水热法和光还原方法成功地制备了铌酸锰-还原氧化石墨烯复合光催化剂。这种复合光催化剂可以明显地提高光催化降解亚甲基蓝的光催化活性,降解效率在60 min内达到了78.2%,是单体铌酸锰降解效率的2倍。通过活性物质捕获实验的研究,增... 详细信息

通过水热法和光还原方法成功地制备了铌酸锰-还原氧化石墨烯复合光催化剂。这种复合光催化剂可以明显地提高光催化降解亚甲基蓝的光催化活性,降解效率在60 min内达到了78.2%,是单体铌酸锰降解效率的2倍。通过活性物质捕获实验的研究,增强的光催化性能可以归因于还原氧化石墨烯加速了光生电子-空穴的分离效率,进而解决了低光催化活性的问题。

关键词：铌酸锰-还原氧化石墨烯光催化剂亚甲基蓝可见光

不同压力梯度平面库埃特流中扰动涡动力学特性

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水动力学研究与进展（A辑） 2014年第5期29卷 599-607页

作者：曹卫东施卫东王党雄国家水泵及系统工程技术研究中心江苏大学流体机械工程技术研究中心江苏镇江212013

该文以不同压力梯度的平面库埃特流动为基本流,在壁面上构建一个局部微振荡射流扰动,利用直接数值模拟的方法求解三维不可压缩N-S方程,模拟了扰动涡结构的生成与演化过程。模拟结果表明:由于压力梯度的差异,虽然射流扰动期间的扰动涡幅... 详细信息

该文以不同压力梯度的平面库埃特流动为基本流,在壁面上构建一个局部微振荡射流扰动,利用直接数值模拟的方法求解三维不可压缩N-S方程,模拟了扰动涡结构的生成与演化过程。模拟结果表明:由于压力梯度的差异,虽然射流扰动期间的扰动涡幅值几乎相同,但幅值在不同的平面库埃特基本流中的演化特性表现出明显的差异;在相同时刻,库埃特基本流压力梯度越大,扰动涡的幅值越大,扰动控制方程中的基本流近壁速度梯度与扰动涡法向速度乘积项对幅值的增长起着主要作用;在不断增长的扰动涡中,呈现高速、低速条纹间隔密集的特性,由于扰动涡的存在,流动区域的近壁面平均切应力系数增加,在增长相对迅速的P??1时的库埃特基本流中形成了相对完整的发卡涡形态的涡量分布。

关键词：库埃特流扰动涡结构压力梯度直接数值模拟