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The Physical Chemistry for the Self-assembly of Peptide Hydrogels

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Chinese Journal of Polymer Science 2018年第3期36卷 366-378页

作者： ying Li yi cao Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and EngineeringJiangsu Engineering Technology Research Centre of Environmental Cleaning MaterialsJiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution ControlJiangsu Joint Laboratory of Atmaspheric Pollution ControlNanjing University of Information Science&TechnologyNanjing 210044China Collaborative Innovation Center of Advanced Microstrucures National Laboratony of Solid State MicrostrucureDepartment of PhysicsNanjing UniversityNanjing 210093China

Peptide hydrogels have been widely used for diverse biomedical applications. However, our current understanding of the physical principles underlying the self-assembly process is still limited. In this review, we summarize our current understanding on the physical chemistry principles from the basic interactions that drive the self-assembly process to the energy landscapes that dictate the thermodynamics and kinetics of the process. We discuss the effect of different factors that affect the kinetics of the self-assembly of peptide fibrils and how this is related to the macroscopic gelation process. We provide our understanding on the molecular origin of the complex and rugged energy landscape for the self-assembly of peptide hydrogels. The hierarchical self-assembled structures and the diverse self-assembling mechanism make it difficult and challenging to rationally design the physical and chemical properties of peptide hydrogels at the molecular revel. We also give our personal perspective to the potential future directions in this field.

关键词： Hydrogel Peptide Self-assembly Kinetics Thermodynamics

Competitive precipitation behavior of hybrid reinforcements in copper matrix composites fabricated by powder metallurgy

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International Journal of Minerals,Metallurgy and Materials 2021年第6期28卷 1090-1096页

作者： Tao Lan yi-hui Jiang Xiao-jun Zhang Fei cao Shu-hua Liang Shaanxi Province Key Laboratory for Electrical Materials and Infiltration Technology Xi’an University of TechnologyXi’an 710048China

Copper matrix composites reinforced by in situ-formed hybrid titanium boride whiskers(TiB_(w))and titanium diboride particles(TiB_(2p))were fabricated by powder *** observations showed competitive precipitation behavior between TiB_(w) and TiB_(2p),where the relative contents of the two reinforcements varied with sintering *** on thermodynamic and kinetic assessments,the precipitation mechanisms of the hybrid reinforcements were discussed,and the formation of both TiB_(w) and TiB_(2p) from the local melting zone was thermodynamically *** precipitation kinetics were mainly controlled by a solid-state diffusion of B *** forming a compact compound layer,in situ reactions were divided into two stages,where Zener growth and Dybkov growth prevailed,***,the competitive precipitation behavior was attributed to the transition of the growth model during the reaction process.

关键词： metal matrix composite hybrid reinforcement in situ reaction growth kinetics

Environmental pollution and DNA methylation： carcinogenesis, clinical significance, and practical applications

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Frontiers of Medicine 2015年第3期9卷 261-274页

作者： yi cao Laboratory of Molecular and Experimental Pathology Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China

Environmental pollution is one of the main causes of human cancer. Exposures to environmental carcinogens result in genetic and epigenetic alterations which induce cell transformation. Epigenetic changes caused by environmental pollution play important roles in the development and progression of environmental pollution-related cancers. Studies on DNA methylation are among the earliest and most conducted epigenetic research linked to cancer. In this review, the roles of DNA methylation in carcinogenesis and their significance in clinical medicine were summarized, and the effects of environmental pollutants, particularly air pollutants, on DNA methylation were introduced. Furthermore, prospective applications of DNA methylation to environmental pollution detection and cancer prevention were discussed.

关键词： environmental pollution DNA methylation cancer biomarker diagnosis therapy prevention

Precipitation evolution and properties of Cu-15Ni-8Sn alloys via Al microalloying during ageing

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Rare Metals 2024年第10期43卷 5216-5228页

作者： Wei Luo Li-jun Peng Xu-jun Mi Hao-Feng Xie yi-Cheng cao Shu-Hui Huang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China School of Materials Science and Engineering South China University of TechnologyGuangzhou 510640China

Studies have shown that microalloying Cu-Ni-Sn alloys using Al inhibits discontinuous precipitation reactions;however,the mechanism has not been investigated ***,this study explored the properties and precipitation evolution of Cu-15Ni-8Sn alloys without and with 1 wt%Al(Cu-15Ni-8Sn-1Al)during ageing at 500℃ through X-ray diffraction(XRD),scanning electron microscopy and high-angle annular dark-field scanning transmission electron *** results revealed that in Cu-15Ni-8Sn alloy,DO_(22)ordering first occurred after spinodal decomposition,subsequently transitioning to an L1_(2)ordering phase,during which the discontinuous precipitates gradually nucleated at the grain boundaries and formed *** alloy hardness increased sharply with ordering and then decreased rapidly after reaching its peak value,due to the dominance of the discontinuous precipitation ***,the DO_(22)ordered phase did not appear during the ageing of Cu-15Ni-8Sn-1Al alloy,and a Ni_(3)(Al_(x),Sn_(1-x))intermetallic compound with L1_(2)structure was formed,consuming Ni and Sn atoms,thereby significantly suppressing the discontinuous precipitation reaction and improving the stability during prolonged *** tensile strength(yield strength)of Cu-15Ni-8Sn and Cu-15Ni-8Sn-1Al alloys at peak hardness were 855(755)and 936 MPa(892 MPa),respectively,and their main strengthening mechanisms were solid solution strengthening and precipitation *** addition of 1 wt%Al effectively improved the precipitation strengthening effect of Cu-Ni-Sn alloys but severely decreased the ductility.

关键词： Cu-15Ni-8Sn Al addition Precipitation sequence Strengthening mechanism

Equivalent circuit model for the insulated core transformer

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Nuclear Science and Techniques 2016年第3期27卷 132-137页

作者： Bo Yang Lei cao jun Yang Sheng-Chi Yan yi-Bin Tao China Electric Power Research Institute Nanjing 210003China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074China

The design of the insulated core transformer(ICT)needs to consider the flux leakage *** equivalent linear circuit model is proposed based on the principle of *** is composed by two types of leakage inductances:conventional leakage between windings and special leakage introduced mainly by the insulation *** values of leakage inductances depend on the dimensions of the core,gaps,or windings and the property of magnetic *** circuit allows for quantitatively evaluating influences of ICT internal parameters on its output *** winding self- and mutual inductance matrix is mathematically converted to derive the inductance *** an example,the leakage parameters of a sixstage two-dimensional(2D) ICT are calculated and analyzed.

关键词：等效电路模型变压器绝缘性能影响电感计算对偶原理等效线性磁性材料

Microstructural refinement and performance improvement of Cu-36 wt%Zn alloy by Al_(2)O_(3)nanoparticles coupling electromagnetic stirring

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Rare Metals 2022年第10期41卷 3560-3565页

作者： Ya-Bo Fu yi-Ping Lu Zhi-jun Wang Zhi-Qiang cao Ai-Jiao Xu School of Physics and Electronic Engineering Taizhou UniversityTaizhou318000China School of Materials Science and Engineering Dalian University of TechnologyDalian116024China School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an710048China

Cu-36 wt%Zn alloy is widely used in valves of water and heating and auto parts,***,the structure is still coarse,and performances are much *** structure and performances of Cu-36 wt%Zn alloy were investigated by adding Al_(2)O_(3)nanoparticles and *** indicate that by Al_(2)O_(3)nanoparticles coupling electromagnetic stirring,the Cu-36 wt%Zn alloy with refined microstructure was successfully *** average grain size is refined by 99%compared with that without nanoparticles and *** tensile strength(R_m)and percentage elongation after fracture(A11.3)increase by 20.58%and 19.40%,respectively,compared with that without nanoparticles and *** increase heterogeneous nucleation rate by 50%compared with that without *** depth of dezincification layer decreases by 78.71%compared with that without nanoparticles and stirring,as protective layer(Cu-Al_(2)O_(3)-Zn)is completely formed around the grain boundaries.

关键词： Microstructural refinement Rotating electromagnetic field Mechanical performance Al_(2)O_(3)nanoparticles

Double layered,one-pot hydrothermal synthesis of M-TiO_2(M=Fe^(3+),Ni^(2+),Cu^(2+)and Co^(2+)) and their application in photocatalysis

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Science China Chemistry 2013年第12期56卷 1783-1789页

作者： CHEN yingying XIE YongBing YANG jun cao HongBin LIU Hui ZHANG yi National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences

A double layered, one-pot hydrothermal method was adopted in this work to prepare transition metal ions （Fe3＋, Ni2＋, Cu2＋ and Co2＋） doped TiO〉 The morphology and chemical properties of TiO2 and the status of metal ions were characterized with XRD, TEM, BET, UV-Vis and XPS analysis. TEM images show that the obtained TiO2 was very uniform with an average particle size of 10.4 nm. XPS, TEM and XRD results show that transitional metals were doped onto TiO2 in the form of ions. Photocatalytic decomposition of oxalic acid under UV illumination and methylene blue degradation under visible light on these materials were conducted, respectively. The results reveal that Cu2＋-TiO2 and C02＋-TiO2 showed a highest activity under UV and visible light illumination, respectively, and they were both more active than commercial P25 TiO2. With this special design of double layers, the hydrolysis of titanium precursor in the system with water can be easily controlled and metal ions are simply doped. This strategy can be further applied to synthesize metal ion doped TiO2 using various metal precursors with controllable amounts, and thus lead to better optimization of highly active photocatalyst.

关键词： double layered hydrothermal synthesis metal ions doped Ti02 photocatalysis

Absorption Complex between Porphyrin and Phenothiazine in Reverse Micelles

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Chinese Chemical Letters 2002年第10期13卷 1007-1010页

作者： jun Hua YU Xue Song WANG Bao Wen ZHANG yi cao Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100101

The interaction between amphiphilic porphyrin and phenothiazine in AOT/isooctane/water reverse micelle was investigated by UV-Vis spectra. A new absorption complex between the two species is formed in such circumstances, which is ascribed to the enrichment of the components by the reverse micelle. The fluorescence quenching of CHTTP by PTH becomes more efficient after the formation of the absorption complex.

关键词： Porphyrin phenothiazine absorption complex reverse micelle.

A semi-analytical pressure and rate transient analysis model for inner boundary and propped fractures exhibiting dynamic behavior under long-term production conditions

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Petroleum Science 2024年第4期21卷 2520-2535页

作者： Lin-Song Cheng Chong cao Quan-Yu Pan Pin Jia Ren-yi cao Zhi-Kai Wang jun-Jie Shi College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China Sinopec Petroleum Exploration and Production Research Institute Beijing100083China CNOOC Research Institute Beijing100028China State Key Laboratory of Water Resources Protection and Utilization in Coal Mining Beijing112211China

The loss of hydrocarbon production caused by the dynamic behavior of the inner boundary and propped fractures under long-term production conditions has been widely reported in recent ***,the quantitative relationships for the variations of the inner boundary and propped fractures have not been determined and incorporated in the semi-analytical models for the pressure and rate transient *** work focuses on describing the variations of the inner boundary and propped fractures and capturing the typical characteristics from the pressure transient curves.A generalized semi-analytical model was developed to characterize the dynamic behavior of the inner boundary and propped fractures under long-term production *** pressure-dependent length shrinkage coefficients,which quantify the length changes of the inner zone and propped fractures,are modified and incorporated into this multi-zone semi-analytical *** simultaneous numerical iterations and numerical inversions in Laplace and real-time space,the transient solutions to pressure and rate behavior are determined in just a few *** dynamic behavior of the inner boundary and propped fractures on transient pressure curves is divided into five periods:fracture bilinear flow(FR1),dynamic PFs flow(FR2),inner-area linear flow(FR3),dynamic inner boundary flow(FR4),and outer-area dominated linear flow(FR5).The early hump during FR2 period and a positive upward shift during FR4period are captured on the log-log pressure transient curves,reflecting the dynamic behavior of the inner boundary and propped fractures during the long-term production *** transient pressure behavior will exhibit greater positive upward trend and the flow rate will be lower with the shrinkage of the inner *** pressure derivative curve will be upward earlier as the inner boundary shrinks more *** lower permeability caused by the closure of un-propped fractures in the inner zone results in gr

关键词： Semi-analytical model Length shrinkage Dynamic behavior Boundary changes Transient behavior