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A Jacobi-collocation method for solving second kind Fredholm integral equations with weakly singular kernels

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Science China Mathematics 2014年第10期57卷 2163-2178页

作者： cai Hao tao School of Mathematics and Quantitative Economics Shandong University of Finance and Economics

In this work,we propose a Jacobi-collocation method to solve the second kind linear Fredholm integral equations with weakly singular ***,we consider the case when the underlying solutions are sufficiently *** this case,the proposed method leads to a fully discrete linear *** show that the fully discrete integral operator is stable in both infinite and weighted square ***,we establish that the approximate solution arrives at an optimal convergence order under the two ***,we give some numerical examples,which confirm the theoretical prediction of the exponential rate of convergence.

关键词： second kind Fredholm integral equations with weakly singular kernels Jacobi-collocation methods stability analysis convergence analysis

Tailoring sulfur-doped and nitrogen-defective carbon nitride nanosheets for efficient photo-controlled radical polymerizations

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Science China Chemistry 2024年第7期67卷 2325-2334页

作者： Xue Li Meng Kai Xu Yuan Huang tao cai Key Laboratory of Biomedical Polymers of Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518057China

Despite the challenges that remain,the synergistic adjustment of various microstructures and photochemical parameters of graphitic carbon nitride(g-C_(3)N_(4))in photocatalytic reactions holds promises for improving catalytic efficiency and reducing energy ***,sulfur-doped and nitrogen-defective g-C_(3)N_(4)(n-SC_(3)N_(x))nanosheets were designed and elaborately *** resultant n-SC_(3)N_(x)possessed a precisely defined 2D layer structure with extensive porosity and incremental specific surface *** photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization of vinyl monomers with low dispersity,excellent temporal control and high chain-end fidelity was achieved under mild blue light irradiation in a nondegassed *** to their ultrathin nanostructures with nitrogen defects and sulfur dopants,n-SC_(3)N_(x)was capable of catalyzing RAFT polymerization in aqueous solutions at significantly accelerated rates,which were nearly 8 times faster compared to bulk g-C_(3)N_(4).The ease of separation and efficient reusability in subsequent polymerizations was enabled by the heterogeneous nature of n-SC_(3)N_(x).The appeal of this approach was illustrated by the fact that utilizing a reusable and metal-free photocatalyst in aqueous environments allowed for the synthesis of polymers with molecular weight up to 300 kg mol^(-1) and a dispersity of 1.32.

关键词： graphitic carbon nitride nitrogen defects sulfur dopants PET-RAFT polymerization recyclability

Non-normal Hasemann Boundary Value Problem

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Wuhan University Journal of Natural Sciences 2001年第3期6卷 649-651页

作者： cai Hao-tao Du Jin-yuan Coll. of Mathematics and Statistics Wuhan University Wuhan 430072 China

We will discuss the non-normal Hasemann boundary value problem: we may find these results are coincided with those of normal Hasemann boundary value problem and non-normal Riemann boundary value problem.

关键词： non-normal positive transformation canonical function

Novel radiation pattern reconfigurable antenna with six beam choices

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The Journal of China Universities of Posts and Telecommunications 2012年第2期19卷 123-128页

作者： cai Xiao-tao WANG An-guo MA Ning LENG Wen School of Electronic Information Engineering Tianjin UniversityTrianjin 300072China

This article presents a novel radiation pattern reconfigurable antenna with six beam choices, which works in 5.2 GHz wireless local area network （WLAN） frequency band. The designed antenna has good impedance matching at the resonant frequency. The beam can be reconfigured to six different directions, and each main lobe of six azimuth patterns has a half power beam width （HPBW） of about 60°. The antenna can cover all directions in the azimuth plane （XY-plane） by controlling the states （ON or OFF） of six switches. Simulation and measurement have been carried out to validate the design and experimental results demonstrate that the proposed antenna has the capacity to provide the pattern reconfigurability.

关键词： antenna pattern reconfigurability parasitic patch WLAN

Visualisation and Heat Transfer Performance of Mini-Channel Flat Heat Pipe with a Binary Mixture

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Journal of Thermal Science 2024年第5期33卷 1712-1725页

作者： FAN Gaoting TANG Aikun cai tao SHAN Chunxian PAN Jun JIN Yi School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China Jiangsu Jinhe Energy Technology Co.Ltd Zhenjiang 212400China

To unravel the intricacies of two-phase gas-liquid flow characteristics and heat transfer behavior,an array mini-channel gravity plate heat pipe(AMGPHP)is proposed in this work,which allows for observing the internal changes in the state of the working *** flow patterns such as pool flow,columnar flow,and slug flow,are experimentally explored and analyzed in *** is found that the optimal volume fill ratio is 20%by utilizing start-up time and thermal resistance as performance evaluation *** this fill ratio,a medium optimization strategy by blending ethanol within R141b is proposed and *** comparison to pure working fluids,the heat transfer performance of AMGFHP in the binary fluid has been significantly augmented due to temperature and concentration shifts resulting from disparate boiling *** the 10%volume fraction ethanol blending condition,the equivalent thermal conductivity of the heat pipe is dramatically elevated,with a value of 3110 W/(m·℃),along with the reduction of the minimum start-up power to 4 *** general,applying such a medium to heat pipes has considerable potential in practical applications.

关键词： flat heat pipe mini-channel visualisation two-phase flow binary mixtures thermal performance

MBRidge: an accurate and cost-effective method for profiling DNA methylome at single-base resolution

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Journal of Molecular Cell Biology 2015年第4期7卷 299-313页

作者： Wanshi cai Fengbiao Mao Huajing Teng tao cai Fangqing Zhao Jinyu Wu Zhong Sheng Sun Beijing Institutes of Life Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute of Zoology Chinese Academy of SciencesBeijing 100101China Experimental Medicine Section NIDCRNational Institutes of HealthBethesdaMD 20892USA Institute of Genomic Medicine Wenzhou Medical UniversityWenzhou 325035China

Organisms and cells,in response to environmental influences or during development,undergo considerable changes in DNA methylation on a genome-wide scale,which are linked to a variety of biological *** MethylC-seq to decipher DNA methylome at single-base resolution is prohibitively *** this study,we develop a novel approach,named MBRidge,to detect the methylation levels of repertoire CpGs,by innovatively introducing C-hydroxylmethylated adapters and bisulfate treatment into the MeDIP-seq protocol and employing ridge regression in data analysis.A systematic evaluation of DNA methylome in a human ovarian cell line T29 showed that MBRidge achieved high correlation(R>0.90)with much less cost(∼10%)in comparison with *** further applied MBRidge to profiling DNA methylome in T29H,an oncogenic counterpart of T29’*** comparing methylomes of T29H and T29,we identified 131790 differential methylation regions(DMRs),which are mainly enriched in carcinogenesis-related *** are substantially different from7567 DMRs that were obtained by RRBS and related with cell development or *** integrated analysis ofDMRsin the promoterand expression of DMR-corresponding genes revealed thatDNAmethylation enforced reverse regulation of gene expression,depending on the distance fromthe proximalDMRto transcription starting sites in both mRNA and *** together,our results demonstrate that MBRidge is an efficient and cost-effective method that can be widely applied to profiling DNA methylomes.

关键词： DNA methylome MB-seq ridge regression single-base resolution

Synthesis and Characterization of a HydrophilicHydrophobic IPN Composed of Poly(vinyl alcohol)and Polystyrene

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Chinese Chemical Letters 2005年第12期16卷 1597-1599页

作者： Yi Zhen TAN Man cai XU Hai tao LI College of Chemistry and Chemical Engineering Hunan Normal University Changsha 410081

A hydrophilic/hydrophobic interpenetrating polymer network （IPN） of poly （vinyl alcohol） / polystyrene was prepared by conversion of the IPN of poly （vinyl acetate）/polystyrene. The hydrophilic/hydrophobic IPN w... 详细信息

关键词： Hydrophilic/hydrophobic interpenetrating polymer network poly(vinyl alcohol) polystyrene

Subnanometric bimetallic Pt-Pd clusters in zeolites for efficient hydrogen production and selective tandem hydrogenation of nitroarenes

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Science China Chemistry 2024年第9期67卷 2911-2917页

作者： Jiafu Li tao cai Yanran Feng Xia Liu Ning Wang Qiming Sun Institute of Sustainable Energy and Resources College of Chemistry and Chemical EngineeringKey Laboratory of Shandong Provincial Universities for Functional Molecules and MaterialsQingdao UniversityQingdao 266071China Innovation Center for Chemical Sciences College of ChemistryChemical Engineering and Materials ScienceJiangsu Key Laboratory of Advanced Negative Carbon TechnologiesSoochow UniversitySuzhou 215123China

The solvolysis of ammonia borane(AB)and the hydrogenation of nitroarenes represent significant reactions for hydrogen generation and value-added chemical *** strategic engineering of the catalysts is imperative for surmounting obstacles associated with their stability and catalytic *** this work,subnanometric bimetallic Pt–Pd clusters were encapsulated within silicalite-1(S-1)zeolites through a ligand-protected in-situ hydrothermal synthesis *** synergetic effect of bimetallic composition and zeolite confinement markedly enhances the catalytic performance of representative Pt_(0.5)Pd_(0.5)@S-1-H catalyst,affording exceptional turnover frequency(TOF)values of 1,043 and 573 mol_(H_(2))mol_(metal)^(-1)min^(-1)for AB hydrolysis and methanolysis at ambient conditions,respectively,surpassing most of the state-of-the-art Pt-based *** and isotopic experiments reveal that the bimetallic catalytic system remarkably boosts the O-H cleavage of water,thereby facilitating the H_(2) production from AB ***,a conspicuous synergistic effect is demonstrated in the shape-selective tandem hydrogenation of nitroarenes,with the bimetallic catalyst facilitating both AB hydrolysis and nitroarene hydrogenation,giving a high TOF value of 1,260 h^(-1)under atmospheric *** study not only demonstrates the effectiveness of bimetallic nanocatalysts encapsulated in zeolites for hydrogen production from chemical hydrogen storage materials,but also paves the way for the design of catalysts with multifunctional active sites capable of synergistically promoting tandem catalytic processes.

关键词： subnanometer bimetallic cluster zeolite synergistic effect ammonia borane solvolysis selective tandem hydrogenation

基于反应气混合物的ICP-MS/MS测定原油中的钒和镍

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光谱学与光谱分析 2025年第1期45卷 101-106页

作者：蔡松韬黄莹秀袁亮代宇宣莫垚坤黄建华湖南工学院材料科学与工程学院湖南衡阳421002 湖南省中医药研究院中药研究所湖南长沙410013

原油中金属元素钒和镍(V和Ni)的含量和比值可为深入了解原油的沉积环境特征和有机质类型发挥重要作用。在原油炼制过程中,V和Ni作为原油催化裂化过程中的有害金属元素,会降低催化剂的活性,严重时会导致催化剂中毒,会严重腐蚀设备,在精... 详细信息

原油中金属元素钒和镍(V和Ni)的含量和比值可为深入了解原油的沉积环境特征和有机质类型发挥重要作用。在原油炼制过程中,V和Ni作为原油催化裂化过程中的有害金属元素,会降低催化剂的活性,严重时会导致催化剂中毒,会严重腐蚀设备,在精炼之前必须对原油中的V和Ni进行脱除处理。V和Ni具有致突变性和致癌性,识别或监测原油中V和Ni进入环境的潜在危险变得越来越重要,对原油中V和Ni的含量进行高灵敏精准测定具有重要意义。采用电感耦合等离子体串联质谱(ICP-MS/MS)测定原油中V和Ni的新策略。原油样品经航空煤油简单稀释后直接采用ICP-MS/MS进行分析,针对V和Ni受到的质谱干扰,在MS/MS模式下,采用由NH_(3)/He(He为缓冲气)和H_(2)组成的反应气混合物(NH_(3)/He/H_(2))作为反应气,基于V^(+)与NH_(3)/He/H_(2)不发生反应,而V^(+)的干扰离子与NH_(3)/He/H_(2)发生反应,采用原位质量法消除干扰,选择V^(+)进行测定;基于Ni^(+)与NH_(3)/He/H_(2)发生反应,采用质量转移法消除干扰,选择无干扰团簇离子Ni(NH_(3))_(3)^(+)进行测定。通过与NH_(3)/He反应模式进行对比研究发现,对于V的测定,加入H_(2)为反应气能快速去除氩基离子的干扰,并能协同NH_(3)消除氧化物离子的干扰;对于Ni的测定,加入H_(2)为反应气能促进全氢加合物(-NH_(3))的形成,从而提高生成Ni(NH_(3))_(3)^(+)的产率。在NH_(3)/He/H_(2)反应模式下,V和Ni的背景等效浓度(BEC)更低,Ni的灵敏度更高,V和Ni的检出限(LOD)分别低至0.83和3.76 ng·kg^(-1),定量限(LOQ)分别为2.77和12.5 ng·kg^(-1)。通过分析标准参考物质NIST SRM 1634c并进行加标回收实验评价方法的准确度和精密度,结果显示,方法的测定结果与标准参考物质的认证值基本一致,V和Ni的加标回收率分别为97.7%和103%,相对标准偏差(RSD)分别为1.8%和1.9%。所建立的分析方法避免了繁琐的样品预处理过程,具有操作简单快速、灵敏度高、准确度和精密度好的特点,适用于原油中V和Ni的检测,能为原油深加工中V和Ni的脱除提供理论依据。

关键词：原油电感耦合等离子体串联质谱钒(V) 镍(Ni) 氨气/氦气/氢气(NH_(3)/He/H_(2))