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Influence of Steric Hindrance Between Hydrogen Atoms of Linkage Groups and Adjacent Phenyls on Properties of Polyimide

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Chemical Research in Chinese Universities 2012年第5期28卷 926-930页

作者： PANG Yu-wei luo long-bo CHEN Yi ZHANG Peng WANG Xu PENG Chao-rong LIU Xiang-yang State key Laboratory of Polymer Material and Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu 610065P.R.China Sichuan Institute of Atomic Energy Chengdu 610066P.R.China

A diamine monomer 4,4′-methylenedianiline（MDA） was introduced to modify the polyimide of pyromellitic dianhydride（PMDA） and 4,4′-oxydianiline（ODA） by polycondensation. A series of polyamic acids was synthesized from MDA and ODA of different molar ratios with PMDA of sum mole of moles of MDA and ODA, and polyimide films were obtained by thermal imidization. Polyimide（PI） films were characterized by tensile testing, dynamic mechanical analysis（DMA）, thermal gravimetry analysis（TGA）, Fourier transform infrared spectroscopy （FTIR）, wide X-ray diffraction（WAXD） and molecular simulation. With the increase of MDA content, the tensile strength and thermal decomposition temperature remained generally stable compared with those of PMDA/ODA polyimide. Unexpectedly, the glass transition temperature（Tg） and Young＇s modulus increased from 388.7 °C and 2.37 GPa to 408.3 °C and 5.74 GPa, respectively. The results of WAXD and molecular simulation indicate the steric hindrance among hydrogen atoms of the linkage groups and adjacent phenyls enhanced the properties of the polyimide modified with MDA.

关键词： Polyimide Modification Glass transition temperature Steric hindrance

Black hole evaporation and its remnants with the generalized uncertainty principle including a linear term

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Communications in Theoretical Physics 2024年第2期76卷 125-136页

作者： bo Yu Zheng-wen long College of Physics Guizhou UniversityGuiyang550025China

In recent years,researchers have investigated the evaporation of Schwarzschild black holes using various forms of the generalized uncertainty principle(GUP),metric quantum correction,and noncommutative geometry,***,there are differences between the GUP correction and the other two methods in terms of describing the later stages of black hole ***,some studies argue that the GUP with a negative parameter cannot effectively correct black hole evaporation,while others contend that the positivity or negativity of the GUP parameters should not affect the correction *** the above into consideration,we reconsider black hole evaporation with the generalized uncertainty principle including a linear term(LGUP),and examine the case of negative *** results indicate that the evaporation behavior of both Schwarzschild black holes and Reissner–Nordstr?m black holes,under LGUP correction,is consistent with the results of metric quantum correction and non-commutative ***,the negative parameter LGUP can also effectively correct for black hole evaporation.

关键词： black hole evaporation generalized uncertainty principle negative parameter

Almost Periodic Type Group Actions on Compact Quantum Metric Spaces

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Acta Mathematica Sinica,English Series 2024年第2期40卷 568-594页

作者： bo Tao long Wei WU College of Mathematics MIIT Key Laboratory of Mathematical Modelling and High Performance Computing of Air VehiclesNanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200241P.R.China

A compact quantum metric space is a complete order unit space A endowed with a Lipnorm *** give some characterizations of almost periodic type group actions on a compact quantum metric space(A,L)by means of several kinds of subsets of A,its induced equicontinuous actions on several important subsets of the dual Banach space A*,and the Lip-norm L with its induced metric space structures on the state space S(A)of A.

关键词： Lip-norm compact quantum metric space Lipschitz isomorphism almost periodicity Arzela-Ascoli theorem metric set

Highly efficient photo-thermal synergistic catalysis of CO_(2)methanation over La_(1-x)Ce_(x)NiO_(3)perovskite-catalyst

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Nano Research 2024年第9期17卷 7945-7956页

作者： Ting Li Zhen-Yu Zhang De-Cun luo bo-Yu Xu Rong-Jiang Zhang Ji-long Yao Dan Li Tao Xie Institute of Industrial Catalysis School of Chemical Engineering and TechnologyXi’an Jiaotong UniversityXi’an 710049China

Solar-driven photo-thermal catalytic CO_(2)methanation reaction is a promising technology to alleviate the problems posed by greenhouse gases ***,designing advanced photo-thermal catalysts remains a research challenge for CO_(2)methanation *** this work,a series of Abo3(A=lanthanide,B=transition metal)perovskite catalysts with Ce-substituted LaNiO3(La_(1-x)Ce_(x)NiO_(3),x=0,0.2,0.5,0.8,1)were synthesized for CO_(2)*** La_(0.2)Ce_(0.8)NiO_(3) exhibited the highest CH_(4) formation rate of 258.9 mmol·g^(-1)·hcat-1,CO_(2)conversion of 55.4%and 97.2%CH_(4) selectivity at 300℃with the light intensity of 2.9 W·cm^(-2).Then the catalysts were thoroughly analyzed by physicochemical structure and optical properties *** partial substitution of the A-site provided more active sites for the adsorption and activation of CO_(2)/H_(2).The sources of the active sites were considered to be the oxygen vacancies(O_(v))created by lattice distortions due to different species of ions(La^(3+),Ce^(4+),Ce^(3+))and exsolved Ni0 by H_(2)*** catalysts have excellent light absorption absorbance and low electron-hole(e^(-)/h^(+))recombination rate,which greatly contribute to the excellent performance in photo-thermal synergistic catalysis(PTC)CO_(2)*** results of in situ irradiated electron paramagnetic resonance spectrometer(ISI-EPR)and ISI-X-ray photoelectron spectroscopy(XPS)indicated that the aggregation of unpaired electrons near the defects and Ni metal(from La and Ce ions to Ov and Ni0)accelerated adsorption and activation of CO_(2)/H_(2).At last,the catalyst properties and structure were correlated with the proposed reaction mechanism from the in situ diffuse reflection infrared Fourier transform spectrum(DRIFTS)*** in situ precipitation of the B-site enhanced the dispersion of Ni,while its enriched photoelectrons upon illumination further promote hydrogen *** H^(*)spillover accelerated t

关键词： photo-thermal catalysis CO_(2)methanation perovskite A-site substitution in situ diffuse reflection infrared Fourier transform spectrum(DRIFTS)

Fabrication of a 3D bioprinting model for posterior capsule opacification using GelMA and PLMA hydrogel-coated resin

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Regenerative Biomaterials 2024年第4期3卷 52-65页

作者： Xin Liu Jiale Li Shuyu Liu Yan long Ching Kang Chen Zhao Ling Wei Shaoqi Huang Yi luo bo Dai Xiangjia Zhu Cataract and Lens Refractive Surgery Group Department of OphthalmologyEye&ENT Hospital of Fudan UniversityShanghai 200031People’s Republic of China NHC Key Laboratory of Myopia Key Laboratory of MyopiaChinese Academy of Medical SciencesFudan UniversityShanghai 200031People’s Republic of China Shanghai Key Laboratory of Visual Impairment and Restoration Shanghai 200031People’s Republic of China Engineering Research Center of Optical Instrument and System the Ministry of EducationShanghai Key Laboratory of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai 200093China

Posterior capsule opacification(PCO)remains the predominant complication following cataract surgery,significantly impairing visual function *** this study,we developed a PCO model that closely mimics the anatomical structure of the crystalline lens capsule *** model incorporated a threaded structure for accurate positioning and observation,allowing for opening and *** 3D printing technology,a stable external support system was created using resin material consisting of a rigid,hollow base and *** replicate the lens capsule structure,a thin hydrogel coating was applied to the resin *** biocompatibility and impact on cellular functionality of various hydrogel compositions were assessed through an array of staining techniques,including calcein-AM/PI staining,rhodamine staining,boDIPY-C11 staining and EdU staining in conjunction with transwell ***,the PCO model was utilized to investigate the effects of eight drugs with anti-inflammatory and anti-proliferative properties,including 5-aminoimidazole-4-carboxamide ribonucleotide(AICAR),THZ1,sorbinil,4-octyl itaconate(4-OI),xanthohumol,zebularine,rapamycin and caffeic acid phenethyl ester,on human lens epithelial cells(HLECs).Confocal microscopy facilitated comprehensive imaging of the PCO *** results demonstrated that the GelMA 605%þPLMA 2%composite hydrogel exhibited superior biocompatibility and minimal lipid peroxidation levels among the tested ***,compared to using hydrogel as the material for 3D printing the entire model,applying surface hydrogel spin coating with parameters of 2000 rpm�2 on the resin-based 3D printed base yielded a more uniform cell distribution and reduced ***,rapamycin,4-OI and AICAR demonstrated potent antiproliferative effects in the drug intervention *** microscopy imaging revealed a uniform distribution of HLECs along the anatomical structure of the crystalline lens capsule with

关键词： posterior capsule opacification(PCO) human lens epithelial cells(HLECs) 3D bioprinting hydrogel resin

Structure engineering of cathode host materials for Li-S batteries

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Rare Metals 2024年第4期43卷 1370-1389页

作者： Jia-Jun long Hua Yu Wen-bo Liu School of New Energy and Materials Southwest Petroleum UniversityChengdu610500China School of Mechanical Engineering Sichuan UniversityChengdu610065China

Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its *** challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode *** the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned *** this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and ***,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in ***,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.

关键词： Lithium-sulfur batteries Structure engineering Cathode Host materials

A Novel 3D Gait Model for Subject Identification Robust against Carrying and Dressing Variations

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Computers, Materials & Continua 2024年第7期80卷 235-261页

作者： Jian luo bo Xu Tardi Tjahjadi Jian Yi College of Information Science and Engineering Hunan Normal UniversityChangsha410000China School of Engineering University of WarwickCoventryCV47ALUK

Subject identification via the subject’s gait is challenging due to variations in the subject’s carrying and dressing conditions in real-life *** paper proposes a novel targeted 3-dimensional(3D)gait model(3DGait)represented by a set of interpretable 3DGait descriptors based on a 3D parametric body *** 3DGait descriptors are utilised as invariant gait features in the 3DGait recognition method to address object carrying and *** 3DGait recognitionmethod involves 2-dimensional(2D)to 3DGaitdata learningbasedon3Dvirtual samples,a semantic gait parameter estimation long Short Time Memory(LSTM)network(3D-SGPE-LSTM),a feature fusion deep model based on a multi-set canonical correlation analysis,and SoftMax recognition ***,a sensory experiment based on 3D body shape and pose deformation with 3D virtual dressing is used to fit 3DGait onto the given 2D gait images.3Dinterpretable semantic parameters control the 3D morphing and dressing *** degree measurement determines the semantic descriptors of 2D gait images of subjects with various shapes,poses and ***,using the 2D gait images as input and the subjects’corresponding 3D semantic descriptors as output,an end-to-end 3D-SGPE-LSTM is constructed and ***,body shape,pose and external gait factors(3D-eFactors)are estimated using the 3D-SGPE-LSTM model to create a set of interpretable gait descriptors to represent the 3DGait Model,i.e.,3D intrinsic semantic shape descriptor(3DShape);3D skeleton-based gait pose descriptor(3D-Pose)and 3D dressing with other ***,the 3D-Shape and 3D-Pose descriptors are coupled to a unified pattern space by learning prior knowledge from the *** research on CASIA B,CMU Mobo,TUM GAID and GPJATK databases shows that 3DGait is robust against object carrying and dressing variations,especially under multi-cross variations.

关键词： Gait recognition human identification three-dimensional gait canonical correlation analysis

Consistent and Accurate TDOA Localization in Dynamic NLOS Environments via Prior Information Independent Estimation

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China Communications 2024年第9期21卷 198-210页

作者： luo Mei long Yu Xiong Youzhi Qin Shuang Key Laboratory of Wireless Sensor Network in University of Sichuan Province College of Physics and Electronic EngineeringSichuan Normal UniversityChengdu 610101China

In the time-difference-of-arrival(TDOA)localization,robust least squares(LS)problems solved by mathematical programming were proven to be superior in mitigating the effects of non-line-of-sight(NLOS)***,the existing algorithms still suffer from two disadvantages:1)The algorithms strongly depend on prior information;2)The approaches do not satisfy the mean square error(MSE)optimal criterion of the measurement *** tackle the troubles,we first formulate an MSE minimization model for measurement noise by taking the source and the NLOS biases as *** obtain stable solutions,we introduce a penalty function to avoid abnormal *** further tackle the nonconvex locating problem with semidefinite relaxation ***,we incorporate mixed constraints and variable information to improve the estimation *** and experiments show that the proposed method achieves consistent performance and good accuracy in dynamic NLOS environments.

关键词： mathematical programming NLOS mitigation robust least squares TDOA

Unimolecular Reactions of E-Glycolaldehyde Oxide and Its Reactions with One and Two Water Molecules

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Research 2024年第1期2023卷 809-824页

作者： Yan Sun bo long Donald G.Truhlar Department of Physics Guizhou UniversityGuiyang 550025China College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China Department of Chemistry Chemical Theory Centerand Supercomputing InstituteUniversity of MinnesotaMinneapolisMN 55455-0431USA

The kinetics of Criegee intermediates are important for atmospheric ***,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy ***,we calculate rate constants for the unimolecular reaction of E-glycolaldehyde oxide[E-hydroxyethanal oxide,E-(CH_(2)OH)CHOO],for its reactions with H_(2)O and(H_(2)O)_(2),and for the reaction of the E-(CH_(2)OH)CHOO…H_(2)O complex with H_(2)*** the highest level of electronic structure,we use W3X-L//CCSD(T)-F12a/cc-pVDZ-F12 for the unimolecular reaction and the reaction with water and W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ for the reaction with 2 water *** the dynamics,we use a dual-level strategy that combines conventional transition state theory with the highest level of electronic structure and multistructural canonical variational transition state theory with small-curvature tunneling with a validated density functional for the electronic structure.

关键词： structure kinetics molecular