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Comprehensive Parameter for Analyzing Condensation in Pneumatic System

Chinese Journal of Mechanical Engineering 2010年第5期23卷 641-646页

作者： JIN yingzi LI yi WANG Yanping WANG Jie ZHU Zuchao Zhejiang Province Key Laboratory of Textile Machinery Zhejiang Sci- Tech University Hangzhou 310018 China The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The condensation in pneumatic system is a complex physical phenomenon dependant upon status variation and phase transitions,which are related to the parameters of the compressed air,atmospheric conditions and the dimensions of the pneumatic *** to now,general research method for this problem is to calculate the status variation and movement quantity by numerical simulation and experiment *** comprehensive parameters composed of several different effect factors are rarely used to study the *** composed components and the working conditions of each cylinder are different,a large number of experiments and complex calculations are necessary to determine the ***,the transferability of the determined results is *** this paper,the charging and discharging systems of serials cylinder with different structure parameters are *** condensation of the systems is observed and the effects of the structure parameters on condensation are *** changing trends of relative humidity,natural frequency and average speed against the structural parameters of the components during discharge of the pneumatic systems are *** comprehensive parameters used to analyze and determine condensation composed by structure parameters of components are proposed,namely,the ratio of the effective area of the discharge tube and the container volume,the square root of the effective area of the discharge tube divided by the product of the container volume and the length of the discharge tube,and the discharge dimensionless *** experimental results show that these comprehensive parameters can be used to quantitatively determine whether internal,external or zero condensation occurs in a pneumatic system,and can be also used to quantitatively analyze the experimental data of condensation in pneumatic systems *** the same time,the effect factors are too much and the effect relationships are very complex,which

关键词： pneumatic system condensation comprehensive parameter structure parameter

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Synthesis and Crystal Structure of 4-Nitro-2-[(2-diethylaminoethylimino)methyl]phenol

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1179-1182页

作者： WANG Feng-Wu WEI yi-Jun ZHU Qi-Yong Department of Chemistry Huainan Normal College Huainan 232001 China

The title Schiff base compound C13H19N3O3 synthesized by the condensation of equimolar 5-nitrosalicylaldehyde and N,N-diethylethane-1,2-diamine consists of two independent molecules. The compound was characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a = 13.151 （3）, b = 20.609（4）, c = 20.991 （4） °A, Z = 16, V = 5689（2） °A^3, Dc = 1.239 g/cm^3, Mr = 265.31, λ（MoKa） = 0.71073 °A, μ= 0.089 mm^-1, F（000） = 2272, R = 0.0732 and wR = 0.1454. A total of 5264 unique reflections were collected, of which 2023 with I 〉 2σ（I） were observed. As expected, the molecule adopts trans configuration about the C=N double bond. The molecules in the crystal are linked through intermolecular hydrogen bonds and π-π interactions, forming a 3-D network.

关键词： Schiff base crystal structure hydrogen bonds π-π interactions

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Molecular simulations of host-guest interactions between zeolite framework STW and its organic structure-directing agents

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Chinese Chemical Letters 2020年第7期31卷 1951-1955页

作者： Chao Shi Lin Li Lixia Yang yi Li State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China International Center of Future Science.Jilin University Changchun 130012China

Zeolites have been widely applied in many chemical processes owing to their featured microporous framework *** structure-directing agents(OSDAs) play an important role during of the formation of zeolite frameworks via non-bonding host-guest *** these interactions is crucial to the design of OSDAs and the synthesis of target ***,we report a molecular simulation study in the host-guest interactions between zeolite framework STW and 21 alkylated imidazolium and pyrazolium cations that have been used as the OSDAs for the synthesis of STW-type *** find that OSDAs that have successfully directed the formation of STW exhibit stronger host-guest interactions than unsuccessful ***,we find all successful OSDAs possess relatively more negative atomic charges on nitrogen atoms and smaller dipole *** to this finding,we have designed seven new alkylated imidazolium and pyrazolium cations that may be suitable for zeolite STW,and verified their structure-directing capability by molecular simulation calculations.

关键词： Zeolite STW Organic structure-directing agent Molecular simulation Host-guest interaction Rational synthesis

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Quantum Heat Engine and Negative Boltzmann Temperature

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Communications in Theoretical Physics 2017年第9期67卷 347-356页

作者： Jing-yi Xi Hai-Tao Quan Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China School of Physics Peking University Beijing 100871 China Collaborative Innovation Center of Quantum Matter Beijing 100871 China

To clarify the ambiguity on negative Boltzmann temperature in literature, we study the Carnot and the Otto cycle with one of the heat reservoirs at the negative Boltzmann temperature based on a canonical ensemble description. The work extraction, entropy production and the efficiency of these cycles are explored. Conditions for constructing and properties of these thermodynamic cycles are elucidated. We find that the apparent "violation" of the second law of thermodynamics in these cycles are due to the fact that the traditional definition of thermodynamic efficiency is inappropriate in this situation. When properly understanding the efficiency and the adiabatic processes, in which the system crosses over "absolute ZERO" in a limit sense, the Carnot cycle with one of the heat reservoirs at a negative Boltzmann temperature can be understood straightforwardly, and it contradicts neither the second nor the third law of thermodynamics. Hence, negative Boltzmann temperature is a consistent concept in thermodynamics. We use a two-level system and an Ising spin system to illustrate our central results.

关键词： quantum heat engines negative Boltzman temperature thermodynamics laws

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Effect of the microstructure parameters on the corrosion characteristics of Mg-Zn-Ca alloy with columnar structure

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Journal of Magnesium and Alloys 2023年第5期11卷 1709-1720页

作者： yi Zhang Xiaohui Feng Qiuyan Huang yingju Li Yuansheng Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shandong Key Laboratory for High Strength Lightweight Metallic Materials Ji’nan 250014China

Magnesium alloys with homogeneous degradation and controlled degradation rate are desirable for biodegradable *** the present work,Mg-3 wt.%Zn-0.2 wt.%Ca alloys with different columnar structures were fabricated and the degradation in 0.9 wt.%NaCl were *** the increase of the growth rate for the directional solidification,the microstructure of the directionally solidified(DSed)alloy evolved from cellular to dendritic coupled with the change of the spacing of the primary trunks(λ_(1))and the volume fraction(fv)of Ca_(2)Mg_(6)Zn_(3) *** results of the corrosion test suggested that the alloy with cellular structure experienced homogeneous corrosion and exhibited the lowest corrosion *** good corrosion resistance of the alloy with cellular structure was attributed to the protective corrosion products film(CPF),which was closely related to the fv of Ca_(2)Mg_(6)Zn_(3) phase andλ_(1).To evaluate the corrosion rates(CR)of the DSed Mg-Zn-Ca alloys with different microstructures,a parameterαwas proposed in this work,which was calculated byλ_(1) and the fv of Ca_(2)Mg_(6)Zn_(3) *** fitting result showed that there was a linear relationship between CR andα,which was CR=4.1899+0.00432α.This means that the CR of the DSed Mg-Zn-Ca alloy can be evaluated if the microstructure had been characterized.

关键词： Mg-Zn-Ca alloy Directional solidification Microstructure Corrosion characterizations Corrosion rate

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A new integration algorithm for finite deformation of thermo-elasto-viscoplastic single crystals

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Acta Mechanica Sinica 2013年第5期29卷 709-717页

作者： Dan Zhao yi-Guo Zhu Ping Hu Wan-Xi Zhang State Key Laboratory of Structural Analysis for Industrial Equipment Faculty of Vehicle Engineering and MechanicsDalian University of Technology

An algorithm for integrating the constitutive equations in thermal framework is presented, in which the plastic deformation gradient is chosen as the integration variable. Compared with the classic algorithm, a key feature of this new approach is that it can describe the finite deformation of crystals under thermal conditions. The obtained plastic deformation gradient contains not only plastic defor- mation but also thermal effects. The governing equation for the plastic deformation gradient is obtained based on ther- mal multiplicative decomposition of the total deformation gradient. An implicit method is used to integrate this evo- lution equation to ensure stability. Single crystal 1 100 aluminum is investigated to demonstrate practical applications of the model. The effects of anisotropic properties, time step, strain rate and temperature are calculated using this integration model.

关键词： Integration algorithm - Thermal effect Anisotropic elasticity Single crystal Finite deformation

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Influence of the axial magnetic field on sheath development after current zero in a vacuum circuit breaker

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Plasma Science and Technology 2017年第6期19卷 20-25页

作者： yi CHEN Fei YANG Hao SUN yi WU Chunping NIU Mingzhe RONG State Key Laboratory of Electrical Insulation and Power Equipment Xi＇an Jiaotong University Xi＇an 710049 People＇s Republic of China

After current zero,which is the moment when the vacuum circuit breaker interrupts a vacuum arc,sheath development is the first process in the dielectric recovery *** axial magnetic field（AMF） is widely used in the vacuum circuit breaker when the high-current vacuum arc is ***,it is very important to study the influence of different AMF amplitudes on the sheath *** objective of this paper is to study the influence of different AMF amplitudes on the sheath development from a micro ***,the particle in cell-Monte Carlo collisions（PIC-MCC） method was adopted to develop the sheath development *** compared the simulation results with the experimental results and then validated the *** also obtained the speed of the sheath development and the energy density of the ions under different AMF *** results showed mat the larger the AMF amplitudes are,the faster the sheath develops and the lower the ion energy density is,meaning the breakdown is correspondingly more difficult.

关键词： vacuum arc sheath PIC-MCC axial magnetic field vacuum circuit breakers

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Application of bedside HINTS,ABCD2 score and truncal ataxia to differentiate cerebellar-brainstem stroke from vestibular neuritis in the emergency room

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Stroke & Vascular Neurology 2024年第6期9卷 685-692页

作者： Xinmin Liu Zhaoxia Li yi Ju Xingquan Zhao Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina China National Clinical Research Center for Neurological Diseases BeijingChina Clinical Center for Vertigo and Balance Disturbance Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Research Unit of Artificial Intelligence in Cerebrovascular Disease Chinese Academy of Medical SciencesBeijingChina Beijing Institute of Brain Disorders Collaborative Innovation Center for Brain DisordersCapital Medical UniversityBeijingChina

Background and purpose Acute vestibular syndrome(AVS)typically manifests as isolated dizziness or vertigo with no apparent neurological ***,distinguishing life-threatening stroke from innocuous peripheral vestibular lesions in the emergency room(ER)remains *** study aimed to explore the ability of the head impulse-nystagmus-test of skew(HINTS)combined with truncal ataxia or ABCD2 score to differentiate stroke from peripheral vestibular disease in patients with AVS in the *** We prospectively recruited 121 patients with AVS from December 2022 to June 2023,69 of whom presented with vestibular neuritis(VN)and the remaining with posterior circulation stroke(PCS).We analysed the HINTS results,truncal ataxia and ABCD2 score and compared the sensitivity and specificity among HINTS,truncal ataxia,ABCD2 score and their combinations using the McNemar test for paired *** HINTS combined with grade 2-3 truncal ataxia achieved significantly higher sensitivity than that of isolated HINTS in differentiating PCS from VN(100%vs 88.5%,p=0.031).The specificity of HINTS plus grade 2-3 truncal ataxia did not significantly differ from that of isolated HINTS(p=0.125);however,the combination of ABCD2 score and HINTS did not improve the diagnostic *** sensitivity of ABCD2 score≥4 plus grade 2-3 truncal ataxia was significantly higher than those of isolated ABCD2 score≥4 or isolated grade 2-3 truncal ataxia(p=0.016 and p<0.001,respectively)and not significantly lower than that of isolated HINTS(p=0.508).Conclusion Compared with the ABCD2 score,the truncal ataxia is of more valuable assistance to HINTS in differentiating *** the combination of ABCD2 score and truncal ataxia has a significant implication,it is not a replacement for HINTS.

关键词： ABCD2 vestibular specificity

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Nonexistence and Longtime Behaviors of Solutions to a Class of Nonlinear Degenerate Parabolic Equations Not in Divergence Form

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 327-332页

作者： Yu-dong SUN yi-min SHI MIN WU School of Science Guizhou Minzu University Department of Applied Mathematics Northwestern Polytechnical University

In this paper, we study the nonexistence and longtime behavior of weak solution for the degenerate parabolic equation σtun=umdiv（｜▽um｜p-2▽um）＋γ｜▽um｜p＋βun with zero boundary condition. Blow-up time is der... 详细信息

关键词： nonexistence nonlinear degenerate parabolic equations weak solution blow-up

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Maintenance of the activity of mono-dispersed Au and Ag nano-particles embedded in agar gel for ion-sensing and antimicrobial applications

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Science China Chemistry 2015年第4期58卷 666-672页

作者： yijuan Long yi Wang Yue Liu Qiaoling Zeng Yuanfang Li Key Laboratory on Luminescence and Real-Time Analysis Ministry of Education College of Chemistry and Chemical Engineering Southwest University College of Pharmaceutical Sciences Southwest University

Composite materials were synthesized by encapsulating Au and Ag nanoparticles in an agar gel matrix. These metallic nano-particles were found to be separately stored, so their optical, catalytic, and antibacterial properties were retained both in the composite gel and a composite membrane. The composite gels were stable under hard external conditions. Based on this, a sensor for the detection of Hg2+ was developed using the Au nanoparticle/agar composite gel. Antibacterial materials were achieved using the Ag nanoparticle/agar composite gel and composite membrane. These two Ag nanoparticle-based materials showed good antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.

关键词： nanoparticles composite materials optical sensors

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