检索结果-南通市图书馆

EXPERIMENTAL INVESTIGATION OF ROTATING STALL FOR A LOW-SPEED CENTRIFUGAL COMPRESSOR

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2008年第3期21卷 76-83页

作者： zhu xiaocheng guo qiang du zhaohui CHEN Hua ZHAO Yan School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China Honeywell Corporation Shanghai 200030 China

Unsteady flows and rotating stall of a low-speed centrifugal compressor are investigated by measuring vaneless diffuser wall static pressure fluctuation and internal flow fields at different small flow fluxes. during the experiment, firstly the real time static pressure fluctuations on the vaneless diffuser shroud at different circumferential and radial position were acquired by high-frequency dynamic pressure transducers. Discrete Fourier transformation analysis and cross-correlation analysis were applied to the experimental results to ascertain the rotating stall beginning operation conditions and stall cells numbers and rotating speed. Secondly, the vaneless diffuser inlet flow angle distribution along diffuser width direction was acquired by single hotwire, which was compared with SENOO＇s analysis results. At last, the internal flow fields of the centrifugal compressor were investigated with a particle image velocimetry （PIV） system at different small flow fluxes. The flow field development of vaneless diffuser and blade flow passage are given at rotating stall conditions. The experiments enrich the understanding of rotating stall flow phenomenon of the low-speed centrifugal compressor and provide full experiment data for designing high performance centrifugal compressor.

关键词： Rotating stall Centrifugal compressor Vaneless diffuser Particle image velocimetry (PIV)

Quantum Dynamics of Bound Entangled 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2期49卷 343-346页

作者： zhu guo-qiang WANG Xiao-Guang Zhejiang Institute of Modern Physics Zhejiang University Hangzhou 310027 China Department of Physics and Institute of Theoretical Physics The Chinese University of Hong Kong Hong Kong China

By using the partial transpose and realignment method, we study the time evolution of the bound entanglement under the bilinear-biquadratie Hamiltonian. For the initial Horodecki＇s bound entangled state, it keeps bound entangled for some time, while for the initial bound entangled states constructed from the unextendable product basis, they become free once the time evolution begins. The time evolution provides a new way to construct bound entangled states, and also gives a method to free bound entanglement.

关键词： entanglement quantum dynamics

在线全文

学校读者我要写书评

暂无评论

高速离心压缩机旋转失速的全流场数值模拟

机械工程学报 2009年第6期45卷 284-289页

作者：郭强竺晓程杜朝辉陈华赵岩上海交通大学机械与动力工程学院上海200030 美国Honeywell公司上海200030

使用商业计算流体动力学(Computational fluid dynamics,CFD)计算软件CFX求解三维雷诺平均的Navier-Stokes方程组,结合出口气腔模型对某带无叶扩压器的离心压缩机的旋转失速现象进行数值模拟。为了准确地模拟小流量下的失速流动现象,在... 详细信息

使用商业计算流体动力学(Computational fluid dynamics,CFD)计算软件CFX求解三维雷诺平均的Navier-Stokes方程组,结合出口气腔模型对某带无叶扩压器的离心压缩机的旋转失速现象进行数值模拟。为了准确地模拟小流量下的失速流动现象,在CFD计算中采用包括蜗壳在内的全场网格。首先使用定常计算得到该离心压缩机的稳态性能曲线,并和试验测量值进行比较。然后引入出口气腔模型,模拟离心压缩机内的旋转失速流动。在小流量下模拟得到离心压缩机内部流场的非定常流动现象。分析气腔模型不同参数对失速流动的影响,气腔体积越大,计算得到的失速频率越低。

关键词：离心压缩机旋转失速气腔模型

Recent progress in optoelectronic neuromorphic devices

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第7期29卷 15-27页

作者： Yan-Bo guo Li-qiang zhu School of Physical Science and Technology Ningbo UniversityNingbo 315211China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China School of Materials Science&Engineering Shanghai UniversityShanghai 200444China

Rapid developments in artificial intelligence trigger demands for perception and learning of external environments through visual perception *** devices and integrated system with photosensing and response functions can be constructed to mimic complex biological visual sensing ***,recent progresses on optoelectronic neuromorphic memristors and optoelectronic neuromorphic transistors are briefly reviewed.A variety of visual synaptic functions stimulated on optoelectronic neuromorphic devices are discussed,including light-triggered short-term plasticities,long-term plasticities,and neural *** optoelectronic neuromorphic devices can also mimic human visual perception,information processing,and *** optoelectronic neuromorphic devices that simulate biological visual perception functions will have potential application prospects in areas such as bionic neurological optoelectronic systems and intelligent robots.

关键词： artificial synapses optoelectronic devices neuromorphic devices visual perception systems

Coercivity enhancement of nanocrystalline hot-deformed Nd-Fe-B magnets by low-melting eutectic MM-Cu(MM=La,Ce,Pr,Nd) alloys addition

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2020年第6期38卷 594-599页

作者： Zheng Jing zhaohui guo Younian He Meiling Zhang Xin Wang Minggang zhu Wei Li Division of Functional Materials Central Iron&Steel Research InstituteBeijing 100081China

MM85Cu15(MM = La,Ce,Pr,Nd) eutectic alloys were added into the hot-deformed Nd-Fe-B magnets to enhance the *** is found that three endothermic peaks occur on the differential scanning calorimetry curve of the MM-Cu melt-spun ribbons at 432.2,451.1 and 516.5℃.The peaks substantially correspond to three types of MM-Cu low-melting eutectic *** coercivity of magnets increases when the MM-Cu content is lower than 4 wt%,and then keeps almost no change with the content further increasing to 5 wt%.The coercivity of the hot-deformed magnets with 4 wt% and without MM-Cu addition is 948 and 683 kA/m,*** all the platelet-shaped grains are isolated by the thickened intergranular phase after MM-Cu ***,the average grain size of the magnets with MM-Cu addition decreases compared with that of the magnet without MM-Cu *** electron microscopy images show that the areal fraction of the RE-rich grain boundary phase increases from 8.6% to 15.1% after MM-Cu *** La,Ce together with Cu and Ga aggregate at the grain boundary regions separating neighboring grains and smoothing the grain ***,both the thickened grain boundary and decreased mean grain size result in the enhancement of coercivity after MM-Cu eutectic alloy addition.

关键词： Hot deformation Nd-Fe-B Coercivity MM-Cu eutectic alloy Rare earths

Effect of microstructure and passive film on corrosion resistance of 2507 super duplex stainless steel prepared by different cooling methods in simulated marine environment

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1100-1114页

作者： Min zhu qiang Zhang Yong-feng Yuan Shao-yi guo School of Mechanical Engineering&Automation Zhejiang Sci-Tech UniversityHangzhou 310018China National and Local Joint Engineering Research Center of Reliability Analysis and Testing for Mechanical and Electrical Products Zhejiang Sci-Tech UniversityHangzhou 310018China

The effect of microstructure and passive film on the corrosion resistance of 2507 super duplex stainless steel(SDSS)in simulated marine environment was investigated by electrochemical measurements,periodic wet–dry cyclic corrosion test,scanning Kelvin probe force microscopy,atomic force microscopy,and X-ray photoelectron *** results show that the occupation ratio ofγphase increases with the decrease in cooling rate,whereas the content ofαphase reduces *** addition,theσprecipitated phase only emerges in the annealed *** pitting sensitivity and corrosion rate of 2507 SDSS reduce first and then increase as the cooling rate ***σprecipitated phase drastically reduces the protective ability of the passive film and facilitates micro-galvanic corrosion of the annealed *** various microstructures,the pits are preferentially distributed within theσandγ*** corrosion resistance of 2507 SDSS prepared by different cooling methods is closely related to the microstructure and structure(stability and homogeneity)of the passive *** steel shows an optimal corrosion resistance,followed by the quenched and annealed steels.

关键词： stainless steel microstructure corrosion resistance passive film

Modulating the Helicity of Sugar-Substituted Perylene Diimide Self-assemblies by Solvent Polarilities

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2015年第1期33卷 95-100页

作者： qiang guo Junchao Wang Lingyun zhu Zhixiang Wei National Center for Nanoscience and Technology Beijing 10190China University of Chinese Academy of Sciences Beijing 100049China

Modulating the helicity of self-assemblies of conjugated molecules is important for their application in chiral *** this communication,solvent effect has been investigated on how to modulate the helicity of supramolecular assemblies of sugar-substituted perylenediimide(PTCDI-BAG)by using UV-Vis,circular dichroism spectroscopy and transmission electron ***-handed helical nanowires are obtained in the mixed solvent system of both N,N-dimethylformamide/ethanol(DMF/ethanol)and N,N-dimethylacetamide/ethanol(DMAC/ethanol).As changing the solvents into dimethyl sulfoxide/ethanol(DMSO/ethanol),ethylene glycol/ethanol(EG/ethanol),or N-methyl-2-pyrrolidone/ethanol(NMP/ethanol),only right-handed heical nanowires are *** chirality of supramolecular structures can be tuned by the controlling of the polarity of the solvents.A theoretical calculation is carried out to explain the chiral optical inversion phenomena of PTCDI-BAG aggregates in different solvents,which reveals that reversed CD spectra is due to the difference of clockwise and anticlockwise rotation of the dimer.

关键词： self-assembly solvent effect helicity conjugated molecules nanowire

Dynamic Alignment of D2 Enhanced by Two Few-cycle Pulses

维普期刊数据库评论

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 Chemical Physics 2008年第5期21卷 421-426页

作者： Zeng-qiang Yang Zhi-rong guo Bao-xiang Yin Mao-zhu Sun Key Laboratory of Ecophysics and Department of Physics Normal College Shihezi University Shihezi832003 China

Dynamic alignment of D2 induced by two few-cycle pulses was investigated by solving the time-dependent Schr6dinger equation numerically based on a rigid rotor model. The results show that alignment of D2 can be enhanced by two few-cycle pulses compared with the level achievable by a single few-cycle pulse as long as the time delay between two pulses is chosen properly, and the pulse duration of two lasers plays an important role in the aligning process of D2 molecules.

关键词： Dynamic alignment Few-cycle pulses Pulse duration

Induced pluripotent stem cells as a potential therapeutic source for corneal epithelial stem cells

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2018年第12期11卷 2004-2010页

作者： Jie zhu Mark Slevin Bao-qiang guo Shou-Rong zhu Queen Mary School Medical College of Nanchang UniversityNanchang 330006Jiangxi ProvinceChina chool of Healthcare Science Faculty of Science and EngineeringManchester Metropolitan UniversityChester StreetManchester M15GDUnited Kingdom Research Institute of Brain Vascular Disease Weifang Medical UniversityWeifang 261000Shandong ProvinceChina Department of Ophthalmology Affiliated Hospital of Weifang Medical UniversityWeifang 261000Shandong Province China

Corneal blindness caused by limbal stem cell deficiency(LSCD) is one of the most common debilitating eye disorders. Thus far, the most effective treatment for LSCD is corneal transplantation, which is often hindered by the shortage of donors. Pluripotent stem cell technology including embryonic stem cells(ESCs) and induced pluripotent stem cells(iPSCs) have opened new avenues for treating this disease. iPSCs-derived corneal epithelial cells provide an autologous and unlimited source of cells for the treatment of LSCD. On the other hand, iPSCs of LSCD patients can be used for iPSCs-corneal disease model and new drug discovery. However, prior to clinical trial, the efficacy and safety of these cells in patients with LSCD should be proved. Here we focused on the current status of iPSCs-derived corneal epithelial cells used for cell therapy as well as for corneal disease modeling. The challenges and potential of iPSCs-derived corneal epithelial cells as a choice for clinical treatment in corneal disease were also discussed.

关键词： induced pluripotent stem cells corneal epithelial cells limbal stem cell deficiency disease modeling