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Syntheses and properties of associative acrylamide copolymers containing short hydrophobic chains used in a friction reducer for slick-water fracturing

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Petroleum Science 2024年第3期21卷 1889-1901页

作者： Ya-Xing Dai xian-li zhang Si-Yuan liu Feng-Run-Ze zhang Yi-Xi zhang Yu-Tong Sang Jing-Xi Zheng Zhao-Sheng liu Peng zhang College of Chemistry and Chemical Engineering Chongqing University of Science and TechnologyChongqing401331China College of Ecology and Environment Chongqing Resources and Environmental Protection of UniversityChongqing401331China China China Property Project Department of Dezhou Mining Property Service CenterShengli Oilfield Company of SinopecDezhou253000ShandongChina

Two allyldimethylalkyl quaternary ammonium salt(AQAS)monomers,N,N-dimethylallylphenylpropylammonium bromide(AQAS1)and N,N-dimethylallylnonylammonium bromide(AQAS2),were synthesized and used to prepare modified polyacrylamide *** new drag reducers were synthesized from acrylamide(AM),sodium acrylate(Na AA)and a cationic modified monomer(AQAS1 or AQAS2)via aqueous solution polymerization,and the copolymers were named P(AM/Na AA/AQAS1)and P(AM/Na AA/AQAS2),*** structures of the drag reduction agents were confirmed by IR and1H NMR *** molecular weight(Mw)of P(AM/Na AA/AQAS1)was 1.79×10^(6)g/*** the copolymer concentration was 1000 mg/L and the flow rate was 45 L/min,in fresh water the highest drag reduction rate was 75.8%,in 10,000 mg/L Na Cl solution the drag reduction rate decreased to 72.9%.The molecular weight of P(AM/Na AA/AQAS2)was 3.17×10^(6)g/*** the copolymer concentration was500 mg/L and the flow rate was 45 L/min,the drag reduction rate reached 75.2%,and in 10,000 mg/L Na Cl solution the drag reduction rate was 73.3%,decreased by approximately 1.9%.The drag reduction rate for partially hydrolyzed polyacrylamide(HPAM)was also investigated,and the results showed that the drag reduction rates for 500 and 1000 mg/L HPAM solutions were merely 43.2%and 49.0%in brine,*** with HPAM,both of the above copolymers presented better drag reduction capacities.

关键词： Shale gas Slick water Drag reducer Modified monomer Copolymerization

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Expert consensus on the diagnosis, treatment, and prevention of respiratory syncytial virus infections in children

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World Journal of Pediatrics 2024年第1期20卷 11-25页

作者： xian-li zhang Xi zhang Wang Hua Zheng-De Xie Han-Min liu Hai-lin zhang Bi-Quan Chen Yuan Chen Xin Sun Yi Xu Sai-Nan Shu Shun-Ying Zhao Yun-Xiao Shang ling Cao Yan-Hui Jia Luo-Na lin Jiong li Chuang-li Hao Xiao-Yan Dong Dao-Jiong lin Hong-Mei Xu De-Yu Zhao Mei Zeng Zhi-Min Chen li-Su Huang Department of Infectious Disease Children's HospitalZhejiang University School of Medicine3333 Binsheng RoadBinjiang DistrictHangzhou 310052China Clinical Research Unit Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina Beijing Pediatric Research Institute Beijing Children's HospitalCapital Medical UniversityBeijingChina Department of Pediatric Pulmonology West China Second University HospitalSichuan UniversityChengduChina Department of Pediatric Pulmonology the Second Affiliated Hospital&Yuying Children's HospitalWenzhou Medical UniversityWenzhouChina Department of Infectious Disease Anhui Provincial Children's HospitalHefeiChina Department of Pediatrics the Second Hospital of Hebei Medical UniversityShijiazhuangChina Department of Pediatrics Xijing Hospitalthe Fourth Military Medical UniversityXi'anChina Department of Infectious Disease Guangzhou Women and Children's Medicine CenterGuangzhou Medicine UniversityGuangzhouChina Department of Pediatrics Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina Department of Respiratory Disease Beijing Children's HospitalCapital Medical UniversityBeijingChina Department of Pediatric Respiratory Shengjing Hospital of China Medical UniversityShenyangChina Respiratory Department Children's Hospital Affiliated to Capital Institute of PediatricsBeijingChina Department of Clinical Epidemiology Aarhus UniversityAarhusDenmark Department of Respirology Children's Hospital of Soochow UniversitySuzhouChina Department of Respiratory Children's Hospital of ShanghaiChildren's Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina Department of Infectious Disease Hainan Women and Children's Medical CenterHaikouChina Department of Infectious Disease Children's Hospital of Chongqing Medical UniversityChongqingChina Department of Respiratory Children's Hospital of Nanjing Medical UniversityNanjingChina Department of Infectious Di

Background Respiratory syncytial virus(RSV)is the leading global cause of respiratory infections and is responsible for about 3 million hospitalizations and more than 100,000 deaths annually in children younger than 5 years,representing a major global healthcare *** is a great unmet need for new agents and universal strategies to prevent RSV infections in early life.A multidisciplinary consensus development group comprising experts in epidemiology,infectious diseases,respiratory medicine,and methodology aims to develop the current consensus to address clinical issues of RSV infections in *** sources The evidence searches and reviews were conducted using electronic databases,including PubMed,Embase,Web of Science,and the Cochrane library,using variations in terms for"respiratory syncytial virus","RSV","lower respiratory tract infection","bronchiolitis","acute","viral pneumonia","neonatal","infant""children",and"pediatric".Results Evidence-based recommendations regarding diagnosis,treatment,and prevention were proposed with a high degree of *** supportive care remains the cornerstone for the management of RSV infections,new monoclonal antibodies,vaccines,drug therapies,and viral surveillance techniques are being rolled *** This consensus,based on international and national scientific evidence,reinforces the current recommendations and integrates the recent advances for optimal care and prevention of RSV *** improvements in the management of RSV infections will require generating the highest quality of evidence through rigorously designed studies that possess little bias and sufficient capacity to identify clinically meaningful end points.

关键词： Consensus prevention Respiratory syncytial virus Treatment

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Parametrization of the Quadratic Function Fields Whose Divisor Class Numbers are Divisible by Three

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Acta Mathematica Sinica,English Series 2009年第4期25卷 593-596页

作者： Wei li xian Ke zhang Department of Mathematical Sciences Tsinghua University Beijing 100084 P. R. China

A parametrization of quadratic function fields whose divisor class numbers are divisible by 3 is obtained by using free parameters when the characteristics of the fields are not 3.

关键词： quadratic function fields divisor class numbers

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Fluent-based numerical simulation of flow centrifugal fan

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Journal of Coal Science & Engineering(China) 2011年第2期17卷 198-200页

作者： li xian-zhang Xuangang Coal-electricity Co. Ltd Datong Coal Mine Group Yuanpin 034114 China

Testing centrifugal fan flow field by physical laboratory is difficult because the testing system is complex and the workload is heavy, and the results observed by naked-eye deviates far from the actual value. To address this problem, the computational fluid dynamics software FLUENT was applied to establish three-dimensional model of the centrifugal fan. The numeral model was verified by comparing simulation data to experimental data. The pressure centrifugal fan and the speed changes in distribution in centrifugal fan was simulated by computational fluid dynamics soft-ware FLUENT. The simulation results show that the gas flow velocity in the impeller increases with impeller radius increase. Static pressure gradually increases when gas from the fan access is imported through fan impeller leaving fans.

关键词： centrifugal fan numerical simulation flow field FLUENT software

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A Novel Real-time Fluorescence Mutant-allele-specific Amplification Method for Rapid Single Nucleotide Polymorphism Analysis

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Chinese Chemical Letters 2006年第4期17卷 499-501页

作者： De Bin ZHU Da XING xian li Lan zhang MOE Key Laboratory of Laser life Science and Institute of Laser life Science South China Normal University Guangzhou 510631

Current methods for single nucleotide polymorphism （SNP） analysis are timeconsuming and complicated. We aimed at development of one-step real-time fluorescence mutant-allele-specific amplification （MASA） method for rapid SNP analysis. The method is a marriage of two technologies： MASA primers for target DNA and a double-stranded DNA-selective fluorescent dye, SYBR Green I. Genotypes are separated according to the different threshold cycles of the wild-type and mutant primers. K-ras oncogene was used as a target to validate the feasibility of the method. The experimental results showed that the different genotypes can be clearly discriminated by the assay. The real-time fluorescence MASA method will have an enormous potential for fast and reliable SNP analysis due to its simplicity and low cost.

关键词： Mutant-allele-specific amplification single nucleotide polymorphism analysis SYBR Green I K-ras oncogene.

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limit Theorems for Critical Galton-Watson Processes with Immigration Stopped at Zero

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Acta Mathematica Sinica,English Series 2024年第2期40卷 435-450页

作者： Dou Dou li Mei zhang xian Yu zhang College of Statistics and Data Science Faculty of ScienceBeijing University of TechnologyBeijing 100124P.R.China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875P.R.China

In this paper,we consider a critical Galton-Watson branching process with immigration stopped at zero *** precise estimation on the probability generating function of the n-th population are obtained,and the tail prob... 详细信息

关键词： Branching immigration critical life period limit theorems

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Ribosomal Protein Genes S23 and L35 from Amphioxus Branchiostoma belcheri tsingtauense:Identification and Copy Number

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Acta Biochimica et Biophysica Sinica 2005年第8期37卷 573-579页

作者： xian li Shi-Cui zhang~* Zhen-Hui liU Hong-Yan li Department of Marine Biology,Ocean University of China,Qingdao 266003,China Department of Marine Biology Ocean University of ChinaQingdao 266003 China

The complete cDNA and deduced amino acid sequences of the ribosomal proteins S23(AmphiS23)and L35(AmphiL35)from amphioxus Branchiostoma belcheri tsingtauense were identified inthis ***23 cDNA is 546 bp long and encodes a protein of 143 amino *** has a predictedmolecular mass of 15,851 Da and a pI of ***35 cDNA comprises 473 bp,and codes for a proteinof 123 amino acids with a predicted molecular mass of 14,543 Da and a pI of ***23 shares morethan 83% identity with its homologues in the vertebrates and more than 84% identity with those in ***35 is more than 63% identical to its counterparts in the vertebrates and more than52% identical to those in the *** blot analysis demonstrated the existence of 1-2 copiesof the S23 gene and 2-3 copies of the L35 gene in the genome of amphioxus *** *** in sharp contrast to the presence of 6-13 copies of the S23 gene and 15-17 copies of the L35 gene in therat *** is clear that the housekeeping genes like S23 and L35 underwent a large-scale duplication inthe vertebrate lineage,reinforcing the gene/genome duplication hypothesis.

关键词： amphioxus ribosomal protein S23 L35 copy number

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Hybrid vibration isolation optimization of a flexible manipulator based on neural network agent model

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Chinese Journal of Aeronautics 2024年第5期37卷 482-505页

作者： Yongxin zhang liang li Dingguo zhang Wei-Hsin liAO xian GUO School of Science Nanjing University of Science and TechnologyNanjing 210094China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

Segmented Active Constrained Layer Damping(SACLD)is an intelligent vibration-damping structure,which could be applied to the sectors of aviation,aerospace,and transportation engineering to reduce the vibration of flexible ***,machine learning technology is widely used in the engineering field because of its efficient multi-objective *** dynamic simulation of a rotational segmental flexible manipulator system is presented,in which enhanced active constrained layer damping is carried out,and the neural network model of Genetic Algorithm-Back Propagation(GA-BP)algorithm is *** suppression and structural optimization of the SACLD manipulator model are studied based on vibration mode and damping *** modal responses of the SACLD manipulator model at rest and rotation are *** addition,the four model indices are optimized using the GA-BP neural network:axial incision size,axial incision position,circumferential incision size,and circumferential incision ***,the best model for vibration suppression is obtained.

关键词： Machine learning Vibration suppression Flexible manipulator Segmented active constrained layer damping Structural optimization

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One Dimensional Iron Molybdophosphate Anionic Chains with Different Structural Arrangements Reflecting a Flexibility Character

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Chemical Research in Chinese Universities 2013年第4期29卷 621-626页

作者： ZHOU Yun-shan HASSAN ul Sadaf li xian-qi zhang li-juan AHMAD Waqar SHI Zong-hai State Key Laboratory of Chemical Resource Engineering Institute of Science Beij'ing University of Chemical Technology Beijing 100029 P. R. China

Structural comparison of a new compound [（bpp）3H6]Fe2ⅢFe2ⅡMo24Ⅴ（H2PO4）8（HPO4）4（PO4）4O48（OH）12·（H2O）4·2H2O（1）[bpp=1,3-di（4-pyridyl）propane] with our previously reported two compounds [（bpy）3FeⅡ]3·Fe2ⅢFe2ⅡMo24Ⅴ（H2PO4）8（HPO4）4（PO4）4O48（OH）12（H2O）4·12H2O（2） and [（bpy）3FeⅡ]2FeⅡFeⅢMo12Ⅴ（H2PO4）2（H2-xPO4）.（H1＋xPO4）（HPO4）2（PO4）2O24（OH）6（H2O）2·9H2O（x=0-1）（3）（bpy=2,2＇-bipyridine）,which all exhibit one-dimensional mixed-valence iron molybdophosphate anionic chains constructed by alternating connection of FeⅢ ions and magic [FeⅡ（Mo6P4O31）2] units,reveals that the non-hydrogen atomic ratios of Mo∶Fe∶P∶O within the polymeric anionic chains are the same for all the three compounds,while the polymeric anionic chains of the different compounds bear different numbers of negative *** therefore there exist different numbers of counter cations per {Fe2Ⅲ[Fe2Ⅱ（P16Mo24ⅤO124）]} unit found in the titled *** discloses that not only are the spatial assembling of counter cations and polymeric inorganic chains of three compounds quite different,but also the O-FeⅢ-O bond angles and FeⅢ-O bond lengths of the three different inorganic chains exhibit small *** is more important is that such small changes in bond length and bond angle in the assemblage of FeⅢ-O bonds lead to the considerable fluctuations of inorganic chains in their structural conformation within the three compounds,reflecting an interesting phenomenon of＂flexibility＂ in the pure inorganic one dimensional mixed-valence iron molybdophosphate chains.

关键词： Flexibility Conformation Crystal structure Inorganic chain Iron molybdophosphate

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Database Construction for Two-Dimensional Material-Substrate Interfaces

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Chinese Physics Letters 2021年第6期38卷 54-60页

作者： xian-li zhang Jinbo Pan Xin Jin Yan-Fang zhang Jia-Tao Sun Yu-Yang zhang Shixuan Du Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physics University of Chinese Academy of SciencesBeijing 100049China School of Information and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of TechnologyBeijing 100081China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

Interfacial structures and interactions of two-dimensional(2D)materials on solid substrates are of fundamental importance for fabrications and applications of 2D ***,selection of a suitable solid substrate to grow a 2D material,determination and control of 2D material-substrate interface remain a big challenge due to the large diversity of possible ***,we propose a computational framework to select an appropriate substrate for epitaxial growth of 2D material and to predict possible 2D material-substrate interface structures and orientations using density functional theory calculations performed for all non-equivalent atomic structures satisfying the symmetry *** approach is validated by the correct prediction of three experimentally reported 2D material-substrate interface systems with only the given information of two parent *** possible interface configurations are also proposed based on this *** therefore construct a database that contains these interface systems and has been continuously *** database serves as preliminary guidance for epitaxial growth and stabilization of new materials in experiments.

关键词： interface stabilization configuration

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