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Effect of C-Tetramethyl Calix[4]resorcinarene Acrylate on Curing Behavior and Film Properties of Thiol-acrylate Coating System

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Chemical Research in Chinese Universities 2009年第5期25卷 760-766页

作者： FU qi shi Wen-fang Joint Laboratory of Polymer Thin Films and Solution Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 P. R. China

An octa-functional acrylate of C-tetramethyl calix[4]resorcinarene（CMC-4-RA） was facilely synthesized and characterized with ^1H NMR, ^13C NMR and FTIR spectroscopy. The CMC-4-RA was added to a thiol-acrylate system with different mass ratios, and exposed to a middle pressure mercury lamp. The maximum photopolymerization rate and final vinyl group conversion in the cured film increased greatly along with CMC-4-RA addition that was monitored with Photo-DSC. The tensile strength and pendulum hardness were improved significantly after the addition of CMC-4-RA. With increasing the content of CMC-4-RA to 60%（mass fraction）, the glass transition temperature increased from 34.2 ℃ to 84.1 ℃; the cross-link density was calculated to be increased from 23.83 mmol/cm^3 to 82.40 mmol/cm^3 according to dynamic mechanical thermal analysis; the thermostability was greatly improved.

关键词： Calixresorcinarene Acrylate UV curing Film

Synthesis and Crystal Structure of 3,5-Diphenyl-1,2-di(4-chlorophenyl)pyrrole

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Chinese Journal of Structural Chemistry 2005年第11期24卷 1314-1317页

作者： shi Da-qing shi Chun-Ling ZHUANG qi-Ya Department of Chemistry Xuzhou Normal University Xuzhou Jiangsu 221116 China Key Laboratory of Biotechnology on MedicalPlants of Jiangsu Province Xuzhou 221116 China

The title compound （C28H19Cl2N） has been synthesized by the reaction of dibenzoylmethane and N-（4-chlorobenzylidene）-4-chlorobenzenamine promoted by low-valent titanium reagent, and characterized by elemental analysis, IR, ^1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P2 1/C with a = 9.952（2）, b = 9.863（2）, c = 23.460（6） A, β = 99.62（2）°, V = 2270.4（9） A^3, Mr = 440.34, Z = 4, Dc = 1.288 g/cm^3, μ（MoKa） = 0.301 mm^-1, F（000） = 912, the final R = 0.0387 and wR = 0.0793. X-ray analysis reveals that the four phenyl rings in the pyrrole ring are not coplanar.

关键词： pyrrole low-valent titanium reagent crystal structure

Evaluating the impacts of converting grain to vegetable fields on nitrate transport in the deep vadose zone of the North China Plain

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Journal of Geographical Sciences 2025年第1期 189-212页

作者： LIU Meiying min Leilei WU Lin ZHANG Yucui qi Yongqing WANG shiqin LIU Binbin GENG Di SHEN Yanjun Hebei Key Laboratory of Water-Saving Agriculture Key Laboratory of Agricultural Water ResourcesCenter for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyCAS School of Advanced Agricultural Sciences University of Chinese Academy of Sciences

Nitrate （NO3-） accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO3-content in intensive agricultural *** land-use change （ALUC）,typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing *** study evaluated the changes in NO3-accumulation and transport in the deep vadose zone （DVZ,below the root zone）,and the groundwater NO3-content associated with ALUC from grain to vegetable fields in the North China Plain （NCP）.The ALUC from grain to vegetable resulted in nitrate–nitrogen （NO3--N） accumulation in DVZ increased by 235.5 kg ha-1m-1（163.2%） in the piedmont plain and 224.9 kg ha-1m-1（102.7%） in the central plain,*** change accelerated downward transport velocity in the DVZ (from 0.81±0.47 to 0.89±0.55 m yr-1in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr-1in the central plain) and increased NO3-leaching *** transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont *** impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.

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Considerations on the concept, definition, and diagnosis of amyotrophic lateral sclerosis

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Neural Regeneration Research 2021年第9期16卷 1723-1729页

作者： Ren-shi Xu min Yuan Department of Neurology Jiangxi provincial People’s HospitalAffiliated People’s Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina

The concept, definition, and diagnosis of amyotrophic lateral sclerosis(ALS) currently present some problems. This article systematically reviews the literature on the history, current concepts, definition, and diagnosis of ALS, and discloses the present problems based on the retrieved literature and the authors' clinical experience. The current concepts and definitions of ALS have not yet been unified or standardized in clinical practice, and are sometimes vague or inaccurate, which can cause difficulties for neurologists in the clinical treatment of ALS. The concept and definition of ALS need to be further ascertained, and the current diagnostic criteria for ALS require further development. The identification of effective and objective biomarkers may be a feasible method for the early and accurate diagnosis of ALS. Therefore, future research should focus on the identification of reliable biomarkers—especially neuroimaging biomarkers—through autopsy. Standardizing the concept and definition of ALS and formulating clear diagnostic criteria will largely avoid many uncertainties in the future clinical research and treatment of ALS, which will greatly benefit patients.

关键词： amyotrophic lateral sclerosis clinical symptoms concept definition diagnosis familial amyotrophic lateral sclerosis motor neuron disease muscle atrophy

Buckling optimization of curvilinear fiber-reinforced composite structures using a parametric level set method

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Frontiers of Mechanical Engineering 2024年第1期19卷 149-160页

作者： Ye TIAN Tielin shi qi XIA State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and *** addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the *** study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite *** the proposed method,the contours of the level set function are used to represent fiber *** a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each ***,the fiber angle at an arbitrary point is the tangent orientation of the contour through this *** the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element *** study considers the parallelism constraint for fiber *** the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design *** numerical examples under different boundary conditions are given to validate the proposed *** show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or ***,the buckling resistance of the final design is significantly improved.

关键词： buckling optimization curvilinear fiber composite structure level set method manufacturing constraint

Predicting Supermassive Black Hole Mass with Machine Learning Methods

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Research in Astronomy and Astrophysics 2022年第8期22卷 182-190页

作者： Yi He qi Guo shi Shao Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

It is crucial to measure the mass of supermassive black holes(SMBHs)in understanding the co-evolution between the SMBHs and their host *** methods usually require spectral data which are expensive to *** use the AGN catalog from the Sloan Digital Sky Survey project Data Release 7(DR7)to investigate the correlations between SMBH mass and their host galaxy *** apply the machine learning algorithms,such as Lasso regression,to establish the correlation between the SMBH mass and various photometric properties of their host *** find an empirical formula that can predict the SMBH mass according to galaxy luminosity,colors,surface brightness,and *** root-mean-square error is 0.5 dex,comparable to the intrinsic scatter in SMBH mass *** 1σscatter in the relation between the SMBH mass and the combined galaxy properties relation is 0.48 dex,smaller than the scatter in the SMBH mass versus galaxy stellar mass *** relation could be used to study the SMBH mass function and the AGN duty cycles in the future.

关键词： (galaxies:)quasars:supermassive black holes galaxies:evolution methods:data analysis

Grant-Free Random Access in Pilot-Reused Multicell Massive MIMO Systems with Backoff Mechanisms

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China Communications 2023年第9期20卷 185-195页

作者： qi Zhang Jun Zhang shi Jin Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China

Grant-free random access(RA)is attractive for future network due to the minimized access *** this paper,we investigate the grantfree RA in multicell massive multiple-input multipleoutput(MIMO)systems with pilot *** backoff mechanism,user equipments(UEs)in each cell are randomly activated,and active UEs randomly select orthogonal pilots from a predefined pilot pool,which results in a random pilot contamination among *** the help of indicators that capture the uncertainties of UE activation and pilot selection,we derive a closed-form approximation of the spectral efficiency per cell after averaging over the channel fading as well as UEs’random *** on the analysis,the optimal backoff parameter and pilot length that maximize the spectral efficiency can be *** find that the backoff mechanism is necessary for the system with large number of UEs,as it can bring significant gains on the spectral ***,as UE number grows,more backoff time is needed.

关键词： backoff mechanism grant-free RA multicell massive MIMO

Evaluating refractive index and birefringence of nonlinear optical crystals:Classical methods and new developments

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Chinese Journal of Structural Chemistry 2023年第1期42卷 46-63页

作者： qi shi Lingyun Dong Ying Wang College of Chemistry and Materials Science Hebei UniversityBaoding071002China College of Biochemistry and Environmental Engineering Baoding UniversityBaoding071002China

Nonlinear optical(NLO)materials play an increasingly important role in laser *** is one of the most important parameters for NLO materials to realize angle phase-matching *** comparison with other desirable optical properties,the availability of birefringence and refractive index dispersion is especially problematic owing to the strict requirements for single *** this review,we described how to obtain the refractive index and birefringence of NLO materials from crystals sub-millimeters to centimeters in ***-cially,recently developed methods including the minimum deflection angle method,auto-collimation method,prism coupling method,oil immersion technique,interference color method,and theoretical calculation(DFT)for rapid assessment of birefringence are summarized,the contents of which are mainly focused on the principles and typical applications,together with the advantages and *** addition,representative examples of bire-fringent measurements were *** purpose of this work is to provide a useful perspective on the characterization of birefringence for NLO *** is hoped that this review can give a clear description of the birefringence measurements and accelerate the discovery of new NLO crystals.

关键词： Nonlinear optical crystals Refractive index Birefringence DFT calculation Phase-matching

Statistical inference for dependence competing risks model under middle censoring

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Journal of Systems Engineering and Electronics 2019年第1期30卷 209-222页

作者： WANG Yan shi Yimin WU min Department of Applied Mathematics Northwestern Polytechnical University School of Science Xi'an Polytechnic University School of Economics & Management Shanghai Maritime University

Middle censoring is an important censoring scheme,in which the actual failure data of an observation becomes unobservable if it falls into a random interval. This paper considers the statistical analysis of the dependent competing risks model by using the Marshall-Olkin bivariate Weibull(MOBW) *** maximum likelihood estimations(MLEs), midpoint approximation(MPA) estimations and approximate confidence intervals(ACIs) of the unknown parameters are obtained. In addition, the Bayes approach is also considered based on the Gamma-Dirichlet prior of the scale parameters, with the given shape *** acceptance-rejection sampling method is used to obtain the Bayes estimations and construct credible intervals(CIs). Finally,two numerical examples are used to show the performance of the proposed methods.

关键词： middle censoring dependent competing risks model Marshall-Olkin bivariate Weibull (MOBW) distribution acceptancerejection sampling.