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Chinese Journal of Polymer Science 2021年第6期39卷 745-755,I0007页

作者： Zhi-Ning Xie Hai-Mu Ye Tong Chen Tian-Ze zheng Jun xu Bao-hua Guo Advanced Materials Laboratory Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Departmentof Materials Science and Engineering College of New Energy and MaterialsChina University of PetroleumBeijing 102249China

The crystallization and melting behavior of polymers is of theoretical *** this work,poly(butylene succinate)(PBS)was selected as an example to study such behavior at low supercooling via introduction of the extended-chain crystal(ECC)of the same polymer as nucleating *** crystallization of PBS with its ECC as nucleating agent in a wide temperature range(90–127°C)and the following melting behavior were *** is revealed that the melting point(Tm',for Tc≥113°C)and the annealing peak temperature(Ta',for Tc=90–100°C)show similar asymptotic *** Tm and Ta approach to a value of ca.3.3°C higher than the corresponding Tc when the crystallization time tc approaches the starting *** is to say,the Hoffman-Weeks plot is parallel to Tm=Tc *** crystallization line became parallel to the melting line when PBS was crystallized at Tc higher than 102°*** on these results,we propose that the parallel relationship and the intrinsic similarity between the Ta and the Tm observed at the two ends of the Tc range could be attributed to the metastable crystals formed at the beginning of crystallization.

关键词： Polymer crystallization Melting temperature Hoffman-Weeks plot Stabilization mechanism Baby crystal

Evaluation of the surface heat budget over the tropical Indian Ocean in two versions of FGOALS

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Atmospheric and Oceanic Science Letters 2016年第5期9卷 343-351页

作者： CAO Ning REN Bao-hua zheng Jian-Qiu xu Di School of Earth and Space Sciences University of Science and Technology of China

Changes of the net ocean surface heat flux（Q_（net）） into the tropical Indian Ocean（TIO） may be an indicator of the climate changes in the Asia and Indian–Pacific Ocean regions with the steadily warming trend in the TIO since the 1950 s. Using two observational ocean surface flux products,this letter evaluates the historical simulations of Q_（net） over the TIO during 1984–2005 in two versions of FGOALS, from CMIP5. The results show that both models present a basin-wide underestimation of net surface heat flux, possibly resulting from the positive latent heat flux biases extending over almost the entire TIO basin. Both models share an Indian Ocean dipole-like bias in the net surface heat flux, consistent with precipitation, SST, and subsurface ocean temperature biases, which can be traced to errors in the South Asian summer monsoon. Area-averaged annual time series analyses of the surface heat budget imply that the FGOALS-s2 bias lies more in radiative imbalance, illustrating the need to improve cloud simulation; while the FGOALS-g2 bias presents ocean surface turbulence flux as the key process, requiring improvement in the simulation of oceanic processes. Neither FGOALS-g2 nor FGOALS-s2 can capture the decreasing tendency of Q_（net） well. All observed and simulated datasets imply surface latent heat flux as the primary contributing component, indicating the simulation biases of models may derive mainly from the biases in simulating latent heat flux. A small latent heat flux increase in models can be considered to be slowed by relaxed wind, increased stability, and surface relative humidity.

关键词： Tropical Indian Ocean heat budget analysis climatology trend FGOALS

Analytical solutions for buckling of size-dependent Timoshenko beams

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Applied Mathematics and Mechanics(English Edition) 2019年第7期40卷 953-976页

作者： Xiaojian xu Mulian zheng Key Laboratory for Special Area Highway Engineering of Ministry of Education School of Highway Chang'an University Xi'an 710064 China Department of Engineering Mechanics Northwestern Polytechnical University Xi'an 710072 China

The inconsistences of the higher-order shear resultant expressed in terms of displacement(s) and the complete boundary value problems of structures modeled by the nonlocal strain gradient theory have not been well addressed. This paper develops a size-dependent Timoshenko beam model that considers both the nonlocal effect and strain gradient effect. The variationally consistent boundary conditions corresponding to the equations of motion of Timoshenko beams are reformulated with the aid of the weighted residual method. The complete boundary value problems of nonlocal strain gradient Timoshenko beams undergoing buckling are solved in closed forms. All the possible higher-order boundary conditions induced by the strain gradient are selectively suggested based on the fact that the buckling loads increase with the increasing aspect ratios of beams from the conventional mechanics point of view. Then, motivated by the expression for beams with simply-supported (SS) boundary conditions, some semiempirical formulae are obtained by curve fitting procedures.

关键词： buckling strain gradient theory boundary condition

Precipitation behavior of P550 steel for non-magnetic drill collars during isothermal aging at 650–900℃

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Journal of Iron and Steel Research International 2022年第4期29卷 636-646页

作者： Li-wei xu huai-bei zheng hua-bing Li Zhou-hua Jiang Shu-cai Zhang Jiang-tao Yu Hao Feng Yue Lin School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114002LiaoningChina

Precipitation behavior of P550 steel for non-magnetic drill collars was investigated by microstructure characterization as well as thermodynamic *** results demonstrate that the main precipitate formed at 650–900℃was cellular Cr_(2)N,and its precipitation depended heavily on the aging *** most sensitive precipitation temperature of cellular Cr_(2)N was 750℃.At 750℃,the cellular Cr_(2)N exhibited fast-slow precipitation kinetics with the aging time *** initial precipitation of cellular Cr_(2)N was governed by the short-range intergranular diffusion of *** long-term aging,its growth was controlled by the long-range bulk diffusion of *** addition,cellular Cr_(2)N induced the precipitation of r phase ahead of the cell after long period of *** the nitrogen content resulted in the increment of both the nucleation site and the driving force for the cellular Cr_(2)N,which jointly promoted its precipitation.

关键词： P550 steel Non-magnetic drill collar Precipitation behavior Cellular Cr_(2)N r Phase Nitrogen

Micro- and nano-mechanics in China： A brief review of recent progress and perspectives

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Science China(Physics,Mechanics & Astronomy) 2018年第7期61卷 18-31页

作者： ZhiPing xu QuanShui zheng Applied Mechanics Laboratory and Center for Nano and Micro Mechanics Department of Engineering Mechanics Tsinghua UniversityBeijing 100084 China

The past three decades have witnessed the explosion of nanoscience and technology, where notable research eftbrts have been made in synthesizing nanomaterials and controlling nanostructures of bulk materials. The uncovered mechanical behaviors of structures and materials with reduced sizes and dimensions pose open questions to the community of mechanicians, which expand the framework of continuum mechanics by advancing the theory, as well as modeling and experimental tools. Researchers in China have been actively involved into this exciting area, making remarkable contributions to the understanding of nanoscale mechanical processes, the development of multi-scale, multi-field modeling and experimental techniques to resolve the processing-microstructures-properties relationship of materials, and the interdisciplinary studies that broaden the subjects of mechanics. This article reviews selected progress made by this community, with the aim to clarify the key concepts, methods and applications of micro- and nano-mechanics, and to outline the perspectives in this fast-evolving field.

关键词： micro- and nano-mechanics multi-scale and multi-field methods nanotechnology nanomaterials nanostructurcs

PREPARATION AND MAGNETIC PROPERTIES OF POLYMERIC COMPLEXES CONTAINING 1,10-PHENANTHROLINE

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Chinese Journal of Polymer Science 2006年第1期24卷 81-86页

作者： hua-jiang Jiang Wei-lin Sun Ren-hua zheng Departrnent of Chemistry and Materials Taizhou Colledge Taizhou 317000 China Department of Polyrner Science and Engineering Zhejiang University Hangzhou 310027 China

A series of polymeric complexes were prepared from Fe^2＋, Co^2＋ or Ni^2＋ and poly（Schiff base）（DAPcIPA）, which was obtained by polycondensation of 5,6-diamino-1,10-phenanthroline （DAP） with isophthalaldehyde （IPA）. The structures of the polymer and the polymeric complexes were characterized by IR, 1^H-NMR and elemental analysis. The magnetic behavior of these complexes was measured as a function of magnetic field strength （0-3.98 ~ 106 A/m） at 5 K and as a function of temperature （5-300 K） at a magnetic field strength of 2.39 × 10^6 A/re. Experimental results show that DAPcIPA-Ni^2＋, DAPcIPA-Co^2＋ are soft ferromagnets while DAPcIPA-Fe^2＋ exhibits features of an antiferromagnet.

关键词： Synthesis Polymer containing phenanthroline Polymeric complexes Organic soft ferromagnets.

Color-tunable circularly polarized electroluminescence from a helical chiral multiple resonance emitter with B–N bonds

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Science China Chemistry 2023年第9期66卷 2612-2620页

作者： Li Yuan Zhen-Long Tu Jun-Wei xu hua-Xiu Ni Zhi-Ping Mao Wen-Ye xu You-xuan zheng State Key Laboratory of Coordination Chemistry Collaborative Innovation Center of Advanced MicrostructuresJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Shenzhen Institute of Information Technology Shenzhen 518172China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China Guangzhou Research&Creativity Biotechnology Co.Ltd. Guangzhou 510700China

Chiral B,N-doped polycyclic aromatic hydrocarbons with circularly polarized luminescence(CPL) and small full-width at halfmaxima(FWHM) are promising multiple resonance(MR) emitters for CP organic light-emitting diodes(CP-OLEDs).This work presents a pair of chiral MR enantiomers,P/M-o[B-N]_(2)N_(2),featuring B–N bonds incorporated within a[7]-helicene *** enantiomers exhibit narrow 0-0 and 0-1 electronic transition bands,whose relative intensity can be fine-tuned by increasing doping concentrations,resulting in redshifts of the emission peak from 542 to 592 *** enantiomers show mirrorsymmetric CPL spectra with an asymmetry factor(|g_(PL)|) of 1.0×10^(-3).The hyperfluorescent CP-OLEDs with double-sensitized emitting layers display a FWHM of 33 nm,an external quantum efficiency of 25.1%,and a|g_(EL)|factor of 7.7×10^(-4).Notably,the CP-OLEDs realize color-tunable CP electroluminescence peak from 553 to 613 nm by regulating the vibrational *** work provides a novel concept for the design of helical CP-MR materials and CP-OLEDs,highlighting their potential for future applications in advanced optoelectronic devices.

关键词： chiral multiple resonance material helical chirality circularly polarized luminescence narrowband emission color-tunable circularly polarized electroluminescence

Crystal Structure and Bovine Serum Albumin Binding Studies of Methyl 4-(2,4-Dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate

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Chinese Journal of Structural Chemistry 2019年第2期38卷 242-250,166页

作者： PENG hua-Nan XIE Jia-Lin CHEN Xi zheng Jie xu He-Tao LIU hua-hua College of Chemistry and Environmental Sciences Shangrao Normal University

The title compound, methyl 4-(2,4-dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate(C_(20) H_(21)Cl_2NO_3, 1) was synthesized and the crystal structure was —determined by single-crystal X-ray diffraction. It crystallizes in tetragonal system, space group P421 c with a = 16.076(3), b = 16.076(3), c = 14.750(2) ?, V = 3811.8(14) ?3, Z = 8, R = 0.0377 and wR = 0.0845. The interactions between compound 1 and bovine serum albumin(BSA) were investigated using fluorescence spectroscopy. The results revealed that compound 1 can effectively quench the intrinsic fluorescence of BSA by static quenching mechanism. The thermodynamic parameters revealed that the action forces between compound 1 and BSA were mainly van der Waals forces and hydrogen bonds. According to F?rster's non-radioactive energy transfer theory, the binding distance between compound 1 and BSA had been determined. Furthermore, the synchronous fluorescence showed that compound 1 has few effects on the microenvironment and conformation of BSA in the binding process.

关键词： 1,4-dihydropyridine crystal structure bovine serum albumin fluorescence quenching

Brain plasticity after peripheral nerve injury treatment with massage therapy based on resting-state functional magnetic resonance imaging

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Neural Regeneration Research 2021年第2期16卷 388-393页

作者： Xiang-Xin Xing Mou-Xiong zheng xu-Yun hua Shu-Jie Ma Zhen-Zhen Ma Jian-Guang xu School of Rehabilitation Science Shanghai University of Traditional Chinese MedicineShanghaiChina Department of Rehabilitation Medicine Yueyang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina Department of Traumatology and Orthopedics Yueyang HospitalShanghai University of Traditional Chinese MedicineShanghaiChina Yangzi Rehabilitation Hospital Tongji UniversityShanghaiChina

Massage therapy is an alternative treatment for chronic pain that is potentially related to brain ***,the underlying mechanism remains *** established a peripheral nerve injury model in rats by unilateral sciatic nerve transection and direct *** experimental rats were treated over the gastrocnemius muscle of the affected hindlimb with a customized massage instrument(0.45 N,120 times/min,10 minutes daily,for 4 successive weeks).Resting-state functional magnetic resonance imaging revealed that compared with control rats,the amplitude of low-frequency fluctuations in the sensorimotor cortex contralateral to the affected limb was significantly lower after sciatic nerve ***,amplitudes were significantly higher in the massage group than in a sham-massage *** findings suggest that massage therapy facilitated adaptive change in the somatosensory cortex that led to the recovery of peripheral nerve injury and *** study was approved by the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine of China(approval No.201701001)on January 12,2017.

关键词： injury massage model neuron peripheral nerve plasticity rat repair

Influence of Interfacial Enantiomeric Grafting on Melt Rheology and Crystallization of Polylactide/Cellulose Nanocrystals Composites

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Chinese Journal of Polymer Science 2022年第1期40卷 93-106页

作者： hua-Gao Fang Kang-Jie Yang Qi-zheng Xie xu Chen Sheng-Li Wu Yun-Sheng Ding Department of Polymer Science and Engineering School of Chemistry and Chemical EngineeringHefei University of TechnologyHefei 230009China Anhui Province Key Laboratory of Advanced Functional Materials and Devices Hefei 230009China Anhui Institute for Food and Drug Control Hefei230051China

Incorporating the surface-grafted cellulose nanocrystals(CNCs)with enantiomeric polylactide(PLLA or PDLA)is an effective and sustainable way to modify PLLA,but their difference in promoting matrix crystallization is still *** this study,the CNCs with identical content and length of PLLA and PDLA(CNC-g-L and CNC-g-D)were prepared and blended with *** rheological properties of PLLA/CNC-gD are greatly improved,indicating that the stereocomplexation can significantly improve the interfacial strength as compared with the conventional van der Waals force in PLLA/***,the matrix crystallizes at a higher rate in PLLA/CNC-g-L than PLLA/***/CNC-g-L15 reaches its half crystallinity in 8.26 min while a longer period of 13.41 min is required for PLLA/*** observation reveals that the superior crystallization behavior in PLLA/CNC-g-L is originated from its higher nucleation efficiency and faster growth *** formation of low content of sc-PLA at the interface can restrict the diffusion of PLLA but contribute less to generate crystalline nuclei,which synergistically leads to the retarded crystallization kinetics in PLLA/*** the mechanism of different interfacial enantiomeric grafting on the melt rheology and crystallization of PLLA is of great significance for the development of high-performance polylactide materials.

关键词： Cellulose nanocrystal Polylactide nanocomposite Interfacial stereocomplexation Crystallization Rheology