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Highly Soluble Polyimides Containing Di-tert-butylbenzene and Dimethyl Groups with Good Gas Separation Properties and Optical Transparency

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Chinese Journal of Polymer Science 2020年第7期38卷 759-768,I0007页

作者： Chen-Yi Wang Cai-Rong Jiang Bin Yu Xiao-Yan Zhao Zhao-Liang Cui Jian Li Qiang Ren jiangsu Collaborative innovation Center of Photovoltaic Science and Engineering Jiangsu Key Laboratory of Environmentally Friendly Polymeric MaterialsSchool of Materials Science and EngineeringChangzhou UniversityChangzhou 213164China State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 210009China

A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups,3,3'-dimethyl-4,4'-diaminophenyl-3",5"-di-tert-butyltoluene,was successfully synthesized by a simple coupling reaction using 3,5-di-tert-butylbenzaldehyde and o-toluidine as starting materials.A series of novel polyimides(PI 3a-3c)with large pendant groups were prepared with the obtained diamine monomer and three different commercial aromatic dianhydrides(3,3',4,4'-biphenyltetracarboxylic dianhydride,4,4'-oxydiphthalic anhydride,and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride)by one-step high temperature *** prepared polyimides exhibited high solubility and good membrane forming ability:they could be dissolved not only in some high boiling solvents such as DMF,NMP,DMAc,and m-Cresol at room temperature,but also in some low boiling solvents such as CHCl3,CH2Cl2,and *** solubility in most solvents could exceed 10 wt%,and the flexible membranes could be obtained by casting their *** prepared membranes exhibited good gas separation *** permeability coefficients of PI 3c for CO2 and O2 were up to 124.6 and 42.8 barrer,respectively,and the selectivity coefficients for CO2/CH4 and O2/N2 were 14.7 and 3.3,*** membranes had light color and good optical *** optical transmittance at 450 nm wavelength was in the range of 67%-79%,and the cutoff wavelength was in the range of 310-348 *** also had good thermal properties with glass transition temperature(Tg)values in the range of 264-302℃.In addition,these membranes possessed good mechanical properties with tensile strength ranging between 77.8-87.4 MPa,initial modulus ranging between 1.69-1.82 GPa,and elongation at break ranging between 4.8%-6.1%.

关键词： Polyimides Di-tert-butyltoluene Gas separation performance Optical transparency

CFD studies of scraper built in SPA clarifying tank based on mixture solid-liquid two-phase flow model

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排灌机械工程学报 2018年第7期36卷 553-559,586页

作者： CHEN Yu ZHOU Jianxu ZHANG Zhengyang College of Water Conservancy and Hydropower Engineering Hohai University China Water Resources Beifang Investigation Design and Research Co.Ltd.

In the industrial process of producing the strong phosphoric acid(SPA),clarification of the solution is essential to the ultimate ***,the large viscosity of sediment and the induced interface interaction result in difficulties when the SPA is *** numerical methodology was applied to simulate internal flow field and performance of the low speed scraper based on Mixture solidliquid two-phase flow *** deposition was generated by loading solid particles at the bottom of clarifying *** moving mesh and RNG k-εmodel were used to simulate the rotational turbulent flow in clarifying *** studied,amongst others,were the scraper rotation speed and the mounting height,which could affect the solid suspension *** of flow field and solid volume fraction distribution in computational domain were presented and *** numerical reports of the scraper torque and velocities of inlet and outlet filed were *** seems the torque value of rotatio-nal axis and particle suspending height augment with an increasing rotating ***,a high revolving speed is good for the deposition *** particle fraction distribution in meridional surface and horizontal surface at fixed rotation speed were analyzed to determine the corresponding optimal installation *** simulating results reflect the flow field is marginally stirred by the scraper and proper working parameters are obtained,in which case the comprehensive properties of the scraper and the clarifying tank are superior.

关键词： strong phosphoric acid clarifying tank scraper mixture two-phase model granular suspension computational fluid dynamics

Mean-square exponential stability for stochastic time-varying delay systems with Markovian jumping parameters:a delay decomposition approach

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Journal of Systems Engineering and Electronics 2011年第5期22卷 816-824页

作者： Li Ma Feipeng Da Key Laboratory of Measurement and Control for Complex Systems of Engineering Ministry of Education Research Institute of Automation Southeast University Nanjing 210096 E R. China College of Electronic and Information Engineering Jiangsu University Zhenjiang 212013 P. R. China

The mean-square exponential stability problem is investigated for a class of stochastic time-varying delay systems with Markovian jumping parameters. By decomposing the delay interval into multiple equidistant subintervals, a new delay-dependent and decay-rate-dependent criterion is presented based on constructing a novel Lyapunov functional and employing stochastic analysis technique. Besides, the decay rate has no conventional constraint and can be selected according to different practical conditions. Finally, two numerical examples are provided to show that the obtained result has less conservatism than some existing ones in the literature.

关键词： stochastic systems time-varying delay Markov chain linear matrix inequality (LMI).

Two novel phase transition materials based on 1-isopropyl-1,4-diazabicyclo[2.2.2]octan-1-ium

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Chinese Chemical Letters 2017年第2期28卷 400-406页

作者： Li-Zhuang Chen Xing-Xing Cao School of Biology and Chemical Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

Two novel phase transition materials,[C9H20N2][Na（BF4）3]（1） and[C9H20N2][（PF6）2]（2）,were synthesized based on 1-isopropyl-1,4-diazabicyclo[2.2.2]octan-1-ium with sodium tetrafluoroborate and hexafluorophosphoric acid,*** scanning calorimetry measurements detected that 1 and 2 underwent reversible phase transitions,which were confirmed by dielectric *** crystal X-ray diffraction data suggested that compound 1 changed from a high temperature phase with a space group of P6_3 to a low temperature one with a space group of P21/c,and that compound 2transformed from the space group of Pbca at room temperature to P21/c at low *** of hydrogen bonds and distortion of l,4-diazabicyclo[2.2.2]octane rings may drive the transitions.

关键词： X-ray diffraction Phase transition Dielectric Differential scanning calorimetry

Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression

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International Journal of Mining Science and Technology 2016年第4期26卷 729-738页

作者： Yang Xuxu Jing Hongwen Chen Kunfu Rock Mass Modeling and Computational Rock Mechanics Laboratories University of Arizona State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology

Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground *** present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical ***,the micro parameters of the PFC^(3D) model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock ***,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint *** low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following *** small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure ***,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency.

关键词： Underground opening Failure behavior Non-persistent joints Rock mass PFC^3D

A novel ferroelectric based on quinuclidine derivatives

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Chinese Chemical Letters 2020年第6期31卷 1686-1689页

作者： Siyu Deng Junyi Li Xiang Chen Yunlong Hou Lizhuang Chen School of Environmental and Chemical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

The compound[(CH3)2 CH-C3 H17 N][CoBr4](1)based on quinuclidine derivatives was achieved by the solution synthetic method and characterized by elemental analysis,infrared spectroscopy,single-crystal X-ray structural analysis and dielectric measurement,***-temperature single-crystal X-ray diffraction suggested that the compound unde rwent the phase transition from the space group C2/c to *** polarization curve was measured using the Sawyer-Tower *** structural phase transitions of 1 was ascribed to the distortion of a[(CH3)2 CH-C3 H17N]2+cation from this inorganicorganic hybrid material[(CH3)2 CH-C3 H17N][CoBr4].The strong change in dielectric anomalies makes compound 1 a suitable candidate for promising switchable dielectric *** work represents a feasible strategy thought for the targeted harvesting of low temperature ferroelectrics.

关键词： Ferroelectric Quinuclidine Phase transition Polarization Dielectric

Theoretical analysis on the deformation characteristics of coal wall in a longwall top coal caving face

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International Journal of Mining Science and Technology 2015年第2期25卷 199-204页

作者： Bai Qingsheng Tu Shihao Li Zhaoxin Tu Hongsheng School of Mines Key Laboratory of Deep Coal ResourceMinistry of EducationChina University of Mining & Technology

Against the background of analyzing coal wall stability in 14101 fully mechanized longwall top coal caving face in Majialiang coal mine,based on the torque equilibrium of the coal wall,shield support and the roof strata,an elastic mechanics model was established to calculate the stress applied on the coal *** displacement method was used to obtain the stress and deformation distributions of the coal *** study also researched the influence of support resistance,protective pressure to the coal wall,fracture position of the main roof and mining height on the coal wall *** following conclusions are drawn:(1) The shorter the distance from the longwall face,the greater the vertical compressive stress and horizontal tensile stress borne by the coal *** coal wall is prone to failure in the form of compressive-shear and tension;(2) With increasing support resistance,the revolution angle of the main roof decreases *** the support resistance and protective force supplied by the face guard increases,the maximum deformation of the coal wall decreases linearly;(3) As the face approaches the fracture position of the main roof,coal wall horizontal deformation increases significantly,and the coal wall is prone to instability;and(4) The best mining height of 14101 longwall face is 3.0 m.

关键词： Longwall top coal caving face Coal wall deformation Torque equilibrium Displacement method Parametric analysis

Experimental and simulated characterization of creep behavior of P92 steel with prior cyclic loading damage

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Journal of Materials Science & Technology 2017年第12期33卷 1540-1548页

作者： Wei Zhang Xiaowei Wang Jianming Gong Yong Jiang Xin Huang School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment Nanjing 211816China Department of Material Textiles and Chemical EngineeringFaculty of Engineering and ArchitectureGhent University.Zwijnaarde B-9052Belgium

The effect of prior cyclic loading on creep behavior of P92 steel was investigated. Creep tests on prior cyclic loading exposure specimens were performed at 650？C and 130 MPa. In order to clarify the influence of prior cyclic loading on creep behavior, optical microscope, scanning electron microscope and transmission electron microscope were used. Experimental results indicate that the prior cyclic loading degrades the creep strength significantly. However, the degradation tends to be saturated with further increase in prior cyclic loading. From the view of microstructural evolution, the recovery of martensite laths takes place during prior cyclic loading exposure. This facilitates the dislocation movement during the following creep process. Therefore, premature rupture of creep test occurs. Additionally, saturated behavior of degradation can be attributed to the near completed recovery of martensite laths. Based on the effect of prior cyclic loading, a newly modified Hayhurst creep damage model was proposed to consider the prior cyclic loading damage. The main advantage of the proposed model lies in its ability to directly predict creep behavior with different levels of prior cyclic loading damage. Comparison of the predicted and experimental results shows that the proposed model can give a reasonable prediction for creep behavior of P92 steel with different level of prior cyclic loading damage.

关键词： Prior cyclic loading Creep behavior Martensite morphology Life prediction

Novel berberine derivatives:Design,synthesis,antimicrobial effects,and molecular docking studies

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Chinese Journal of Natural Medicines 2018年第10期16卷 774-781页

作者： YAO Ling WU Ling-Ling LI Qian HU Qin-Mei ZHANG Shu-Yuan LIU Kang JIANG Jian-Qin School of Traditional Chinese Pharmacy China Pharmaceutical University

A series of berberine derivatives were synthesized by introducing substituted benzyl groups at *** these synthesized compounds（4a–4m）were screened for their in vitro antibacterial activity against four Gram-positive bacteria and four Gram-negative bacteria and evaluated for their antifungal activity against three pathogenic fungal *** these compounds displayed good antibacterial and antifungal activities,compared to reference drugs including Ciprofloxacin and Fluconazole;Compounds 4f,4g,and 4l showed the highest antibacterial and antifungal ***,all the synthesized compounds were docked into topoisomerase Ⅱ-DNA complex,which is a crucial drug target for the treatment of microbial *** results showed that H-bond,π-πstacked,π-cationic,andπ-anionic interactions were responsible for the strong binding of the compounds with the target protein-DNA complex.

关键词： Antimicrobial drugs Berberine derivatives Molecular docking Topoisomerase Ⅱ DNA gyrase SAR