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Preliminary Study on Lipase-catalyzed Synthesis of Polyesters Containing L-Malic Acid Units

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Chinese Chemical Letters 2006年第12期17卷 1611-1614页

作者： Da hu YAO guang Ji LI College of Materials Science and Engineer South China University of Technology Guangzhou 510640

Terpolymer of 1, 8-octanediol, adipic acid, and L-malic acid was synthesized via a lipase-catalyzed direct polycondensation. The products were characterized by GPC and 1H NMR. The results indicated that the molecular weight of the prepared polymers decreased with increasing L-malic acid content in the monomer feed ratio, and that change in the L-malic acid content from 0 to 20 mol % did not remarkably influenced on the molecular weight distribution Mw /Ma of the prepared samples. The 1H NMR spectra of the obtained copolymer samples showed that hydroxyl groups of L-malic acid did not take part in the polymerization reaction.

关键词： L-Malic acid polycondensation lipase polyester.

Recycling strategies for vitrimers

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International Journal of Smart and Nano Materials 2022年第3期13卷 367-390页

作者： Haochuan Zhang Jingjing Cui guang hu Biao Zhang Frontiers Science Center for Flexible Electronics(FSCFE) Ningbo Institute of Northwestern Polytechnical UniversityNorthwestern Polytechnical UniversityXi’anShaanxiChina Queen Mary University of London Engineering School Northwestern Polytechnical University(NPU)Xi’anP.R.China

Vitrimer is a new type of material that combine the advantages of thermoplastic and thermoset *** rapid dynamic exchange reactions at high temperature allow the topology of cross-linked networks to change and rearrange while keeping material structures and properties *** concept of vitrimer has emerged to provide a viable strategy for the recycling of highperformance polymer materials,and lots of research works have been carried out for the development of various types of *** addition,the recycling strategies for vitrimers are particularly important to determine the performance and potential applications of the recovered ***,it is an innovative and valu-able perspective to discuss vitrimer materials according to their different recycling *** this review,we start with a brief overview of vitrimers,and then,focus on recycling strategies for ***,we highlight the advantages and disadvan-tages of the two different recycling strategies:physical and chemi-cal recycling methods,and then explore the feasibility of upcycling vitrimers using 3D printing ***,the impact of recy-cling strategies on vitrimer materials and the prospects for max-imizing the use of vitrimer materials are discussed.

关键词： Vitrimers chemical recycling physical recycling 3D printing

Friedmann Cosmology with a Generalized Equation of State and Bulk Viscosity

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Communications in Theoretical Physics 2007年第2期47卷 379-384页

作者： MENG Xin-He REN Jie hu Ming-guang Department of Physics Nankai University Tianjin 300071 China

The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].

关键词： Friedmann cosmology equation of state bulk viscosity dark energy

DLF-YOLOF:an improved YOLOF-based surface defect detection for steel plate

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Journal of Iron and Steel Research International 2024年第2期31卷 442-451页

作者： guang-hu Liu Mao-xiang Chu Rong-fen Gong Ze-hao Zheng School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan114051LiaoningChina

Surface defects can affect the quality of steel *** methods based on computer vision are currently applied to surface defect detection of steel ***,their real-time performance and object detection of small defect are still *** improved object detection network based on You Only Look One-level Feature(YOLOF)is proposed to show excellent performance in surface defect detection of steel plate,called ***,the anchor-free detector is used to reduce the network ***,deformable convolution network and local spatial attention module are introduced into the feature extraction network to increase the contextual information in the feature ***,the soft non-maximum suppression is used to improve detection accuracy ***,data augmentation is performed for small defect objects during training to improve detection *** show the average precision and average precision for small objects are 42.7%and 33.5%at a detection speed of 62 frames per second on a single GPU,*** shows that DLF-YOLOF has excellent performance to meet the needs of industrial real-time detection.

关键词： Steel surface defects detection YOLOF Anchor-free detector Small object detection Real-time detection

human embryos in a dish - modeling early embryonic development with pluripotent stem cells

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Cell Regeneration 2022年第1期11卷 40-43页

作者： Xiukun Wang guang hu Epigenetics and Stem Cell Biology Laboratory National Institute of Environmental Health Sciences Research Triangle ParkDurhamNC 27709USA

Stem cell-based embryo models present new opportunities to study early embryonic *** a recent study,Kagawa et *** an approach to create human pluripotent stem cell-based blastoids that resemble the human *** blastoids efficiently generated analogs of the EPI,TE,PrE lineages with transcriptomes highly similar to those found in ***,the formation of these lineages followed the same sequence and pace of blas-tocyst development,and was also dependent on the same pathways required for lineage ***,the blastoids were capable of attaching to stimulated endometrial cells to mimic the process of *** more comprehensive analysis is needed to confirm its validity and usefulness,this new blastoid system presents the latest development in the attempt to model early human embryogenesis in vitro.

关键词： Pluripotent stem cells Stem cell-based embryo models Blastoid

Torsional deformation-induced gradient hierarchical structure in a 304 stainless steel

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Journal of Iron and Steel Research International 2021年第6期28卷 722-728页

作者： Jia-long Tian guang hu Wei Wang Yi-yin Shan Zhou-hua Jiang School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Institute of Metal Research Chinese Academy of SciencesShenyang 110016LiaoningChina Shenyang RongRong Science and Technology Co. Ltd.Shenyang 110000LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

After applying torsion to cylindrical 304 stainless steel samples,a gradient structure along the radial direction was *** was found that the volume fraction of a0-martensite increased gradually from the center to the surface of *** possibility of deformation-induced martensitic transformation was analyzed theoretically,whose conclusions were consistent with the experimental *** was found that torsional deformation could produce abundant deformation twin and deformation-induced martensite,which could affect the tensile property of steel *** existence of deformation and martensite during torsion could increase the strength but deteriorate the ductility dramatically during the tensile test,which should be attributed to the weakening of work hardening *** a result of severe deformation,both strain-induced and stress-induced martensite have been ***,two types of martensitic transformation mechanisms during torsional deformation were discussed.

关键词： Gradient material Torsional deformation Thermodynamic calculation 304 stainless steel Martensitic transformation

Optimal design of coded aperture used for Z-Pinch driven fusion neutron imaging

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Science China(Technological Sciences) 2015年第7期58卷 1289-1293页

作者： JIA QingGang hu huaSi ZHENG XiangYang ZHANG FengNa WANG DongMing hu guang ZHANG TianKui WU YueLei Institute of Nuclear Science and Technology Xi'an Jiaotong University State Environmental Protection Administration (SEPA) Nuclear and Radiation Safety Centre Research Center of Laser Fusion China Academy of Engineering Physics

Currently,the neutron yield of Z-Pinch is lower than that of laser driven *** the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of the reconstructed fusion core,especially in the condition of low neutron *** this paper,mathematical model is purposed to describe the dependence of aperture parameters on the imaging *** investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread *** to this,a novel non-uniform redundancy penumbra apertures array is *** addition,the imaging performances of this novel coded aperture,penumbra aperture and ring aperture are evaluated and compared by Monte Carlo *** comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low *** encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield.

关键词： Z-pinch driven fusion neutron imaging coded aperture signal to noise ratio low neutron yield

基于弹丸膛内运动参数和压力测试的火炮膛内燃气温度估算方法

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火工品 2025年第1期 51-54页

作者：赵煜华闫光虎肖霞严文荣梁磊西安近代化学研究所陕西西安710065

为了解决火炮膛内测试环境恶劣而导致发射药燃气温度测试难度大的问题,基于微波干涉仪、压力测试系统,结合发射药配方性能计算理论、装药内弹道性能计算模型等理论,建立了一种基于实测参数的火炮膛内燃气温度估算方法,并开展了试验研究... 详细信息

为了解决火炮膛内测试环境恶劣而导致发射药燃气温度测试难度大的问题,基于微波干涉仪、压力测试系统,结合发射药配方性能计算理论、装药内弹道性能计算模型等理论,建立了一种基于实测参数的火炮膛内燃气温度估算方法,并开展了试验研究。结果表明:火炮膛内燃气温度的最高值约为2631.8 K,随着弹丸运动迅速降低,弹丸出炮口时膛内燃气温度降低到约1858.4 K;建立的火炮膛内发射药燃气温度估算方法可以有效地获得火炮整个内弹道过程中火药燃气温度随时间的变化规律,为低烧蚀发射药及装药的研制提供了一种新的研究手段。

关键词：发射药膛内燃气温度估算方法微波干涉仪

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Synthesis of Novel Electron Donors and Their Application to Propylene Polymerization

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Transactions of Tianjin University 2012年第1期18卷 8-14页

作者： GUO Jintang hu guang CHEN Zhikun School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China

A series of electron donors,including 1,1-cyclopentanecarboxylic acid diethyl ester (CPCADEE),1,1cyclopentanedimethanol acetic diester (CPDMAD),1,1-biethoxymethyl pentane (BEMP),2,2-diethyl diethylmalonate (DEDEM)and 2,2-diethyl-1,3-propanediol acetic diester (DEPDADE),were synthesized by diethyl malonate (DEM).The purities and structures of the above products were characterized by gas chromatography (GC) and gas chromatography-mass spectrometer (GC-MS),***,the possible optimal three-dimensional structures of these donors were simulated by means of Gaussian 03 and Chem *** these electron donors were coordinated with tetrachloro titanium (TiCl 4) and chloride magnesium (MgCl 2)to obtain the catalysts for the polymerization of *** catalytic activities and properties of polypropylene are greatly improved by adding external donor(ED) when CPCADEE or DEPDADE is used as internal donor(ID).However,when BEMP was used as ID,the highest catalytic activity is obtained without adding ED,which can reduce production costs and simplify catalytic *** experiments indicate that BEMP has the shortest distance of oxygen atoms and the highest electronegativity.

关键词： electron donor structural simulation propylene polymerization 1,1-biethoxymethyl pentane