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Extremal P_(8)-Free/P_(9)-Free Planar Graphs

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Journal of the Operations Research Society of China 2023年第3期11卷 451-457页

作者： Yong-Xin Lan Yong-tang shi School of Science Hebei University of TechnologyTianjin300401China Center for Combinatorics and LPMC Nankai UniversityTianjin300071China

An H-free graph is a graph not containing the given graph H as a *** is well known that the Turán number ex(n,H)is the maximum number of edges in an H-free graph on n *** on this definition,we define ex_(P)(n,H)to restrict the graph classes to planar graphs,that is,ex_(P)(n,H)=max{|E(G)|:G∈G,where G is a family of all H-free planar graphs on n ***,we have ex_(P)(n,H)=3n−6 if the graph H is not a planar *** study is initiated by Dowden(J Graph Theory 83:213–230,2016),who obtained some results when H is considered as C_(4)or C_(5).In this paper,we determine the values of ex_(P)(n,Pk)with k∈{8,9},where Pk is a path with k vertices.

关键词： Turán number Extremal graph Planar graph

NUMERICAL ANALYSIS FOR CIRCULATION DISTRIBUTION OF PROPELLER BLADE

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Journal of Hydrodynamics 2010年第4期22卷 488-493页

作者： HONG Fang-wen DONG shi-tang China ship Scientific Research Center Wuxi 214082 China

A process for numerical analysis of radial circulation distribution of propeller blade is proposed and *** is based on the results of numerical simulation of the velocity field around propeller blades and in the *** well-known traditional method using tangential velocity data in the wake and applying Stockes＇s theorem was also examined in the *** results from two approaches are compared with each *** is found that if the traditional way is utilized,in many cases an unexpected ＂hump＂ appears in the circulation distribution at certain outer *** authors calculated the circulations directly around blade sections,and it is referred as direct *** unexpected hump of the circulation distribution disappears in the results of direct *** article also discusses the reasons of the appearance of the unexpected hump in traditional *** direct method is proposed to have a potential in analyzing or verifying the radial road distribution for designed propeller and the numerical analysis instead of experimental validation for circulation distribution can be as a tool in the propeller design process.

关键词： propeller blade circulation distribution load distribution

Hopf bifurcation control of a Pan-like chaotic system

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Chinese Physics B 2018年第9期27卷 374-379页

作者： Liang Zhang Jia-shi tang Qin Han College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China College of Mechanical Engineering Wuchang Institute of TechnologyWuhan 430065China

This paper is concerned with the Hopf bifurcation control of a modified Pan-like chaotic system. Based on the Routh-Hurwtiz theory and high-dimensional Hopf bifurcation theory, the existence and stability of the Hopf bifurcation depending on selected values of the system parameters are studied. The region of the stability for the Hopf bifurcation is *** the hybrid control method, a nonlinear controller is designed for changing the Hopf bifurcation point and expanding the range of the stability. Discussions show that with the change of parameters of the controller, the Hopf bifurcation emerges at an expected location with predicted properties and the range of the Hopf bifurcation stability is expanded. Finally,numerical simulation is provided to confirm the analytic results.

关键词： Hopf bifurcation control Pan-like chaotic system Routh-Hurwtiz hybrid control method stability control high-dimensional Hopf bifurcation

Hypergraph Turan Numbers of Vertex Disjoint Cycles

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Acta Mathematicae Applicatae Sinica 2022年第1期38卷 229-234页

作者： Ran GU Xue-liang LI Yong-tang shi Center for Combinatorics and LPMC Nankai UniversityTianjin 300071China

The Turan number of a k-uniform hypergraph H,denoted by exk(n;H),is the maximum number of edges in any k-uniform hypergraph F on n vertices which does not contain H as a *** Cl(k)denote the family of all k-uniform minimal cycles of length l;S(l1,…,lr)denote the family of hypergraphs consisting of unions of r vertex disjoint minimal cycles of lengthl1,…lr,respectively,and Cl(k)denote a k-uniform linear cycle of length *** determine precisely exk(n;S(l1,…,lr)and exk(n;Cl1(k),…,Cl1(k)for sufficiently large *** results extend recent results of Füredi and Jiang who determined the Turan numbers for single k-uniform minimal cycles and linear cycles.

关键词： Turan number cycles extremal hypergraphs

Differentiation of retinal ganglion cells from induced pluripotent stem cells: a review

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International Journal of Ophthalmology(English edition) 2019年第1期12卷 152-160页

作者： Shang-Li Ji shi-Bo tang Aier Eye Institute Aier School of Ophthalmology Central South University

Glaucoma is a common optic neuropathy that is characterized by the progressive degeneration of axons and the loss of retinal ganglion cells(RGCs). Glaucoma is one of the leading causes of irreversible blindness worldwide. Current glaucoma treatments only slow the progression of RGCs loss. Induced pluripotent stem cells(iPSCs) are capable of differentiating into all three germ layer cell lineages. iPSCs can be patient-specific,making iPSC-derived RGCs a promising candidate for cell replacement. In this review, we focus on discussing the detailed approaches used to differentiate iPSCs into RGCs.

关键词： glaucoma retinal ganglion cells induced pluripotent stem cells differentiation

Analysis on Composition Rules of Chinese Patent Drugs Treating Pain-Related Diseases Based on Data Mining Method

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Chinese Journal of Integrative Medicine 2019年第11期25卷 861-866页

作者： tang shi-huan SHEN Dan YANG Hong-jun Institute of Chinese Materia Medica China Academy of Chinese Medical Sciences

Objective: To analyze the composition rules of oral prescriptions in the treatment of headache, stomachache and dysmenorrhea recorded in National Standard for Chinese Patent Drugs(NSCPD) enacted by Ministry of Public Health of China and then make comparison between them to better understand pain treatment in different regions of human body. Methods: Constructed NSCPD database had been constructed in 2014. Prescriptions treating the three pain-related diseases were searched and screened from the database. Then data mining method such as association rules analysis and complex system entropy method integrated in the data mining software Traditional Chinese Medicine Inheritance Support System(TCMISS) were applied to process the data. Results: Top 25 drugs with high frequency in the treatment of each disease were selected, and 51, 33 and 22 core combinations treating headache, stomachache and dysmenorrhea respectively were mined out as well. Conclusions: The composition rules of the oral prescriptions for treating headache, stomachache and dysmenorrhea recorded in NSCPD has been summarized. Although there were similarities between them, formula varied according to different locations of pain. It can serve as an evidence and reference for clinical treatment and new drug development.

关键词： Chinese patent drug headache stomachache dysmenorrhea pain Traditional Chinese Medicine Inheritance Support System formulating principle

TDC-GPX-based synchronization scheme for QKD system

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Nuclear Science and Techniques 2016年第1期27卷 88-92页

作者： Lian-Jun Jiang shi-Biao tang Ze-Jie Yin State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Department of Modern Physics University of Science and Technology of China

To meet the needs of signal alignment between the transmitter and receiver in a quantum key distribution(QKD) system, we put forward a TDC-GPX-based synchronization scheme, which is based on high-precision time measurement. We send a low-frequency repeat optical pulse synchronized with associated quantum signals on the receiver's side by using a time-to-digital converter(TDC)module, the time intervals between quantum signals, and synchronization signals measured and converted to corresponding temporal orders to complete the *** state the principle of the synchronization scheme in detail and then verify it in an actual QKD test bed. The test results show that our TDC-GPX-based synchronization can obtain a time resolution better than 100 ps, and the proposed scheme shows full feasibility for an actual QKD system.

关键词： TDC QKD GPX 同步系统量子密钥分配时间数字转换器信号调整

Synthesis and applications of thiosulfonates and selenosulfonates as free-radical reagents

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Chinese Chemical Letters 2023年第4期34卷 53-66页

作者： Xin Wang Jianping Meng Dongyang Zhao shi tang Kai Sun College of Chemistry and Chemical Engineering Yantai UniversityYantai 264005China College of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China

Chalcogenative sulfones(thiosulfonates and selenosulfonates), as reactants for organic transformations,are widely used and interesting because of their potential to react with nucleophiles, electrophiles, and free radicals. As stable radical reagents, the synthesis and applications of chalcogenative sulfones have opened up a novel pathway to synthesize many kinds of compounds containing sulfur or selenium motifs. However, despite the numerous recent works on the synthesis and applications of thiosulfonates and selenosulfonates as radical reagents, no review has yet provided a summary of the literature. In this paper, we aim to review the synthesis and applications strategies of chalcogenative sulfones as radical reagents reported over the past several decades. Different types of catalysis are discussed in this review:(i) metal catalysis;(ii) visible-light catalysis;(iii) synergistic catalysis;and(iiii) other types. Concurrently,in visible-light catalysis and metallaphotoredox catalysis sections, we highlight that developing relatively environmentally friendly synthetic methods in this area is always a great challenge, but also a persistent pursuit. Finally, the scopes, limitations, mechanisms, and existing problems of some reactions are described briefly.

关键词： Chalcogenative sulfones Radical Synthesis Applications Mechanisms

Stereoselective C(sp^3)-C(sp^2) Negishi coupling of (2-amido-1-phenylpropyl)zinc compounds through the steric control of β-amido group

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Science China Chemistry 2013年第9期56卷 1293-1300页

作者： tang shi LI ShuHua ZHOU Dong ZENG HuiQiong WANG NaiXing College of Chemistry and Chemical Engineering Jishou University Technical Institute of Physics and chemistry Chinese Academy of Sciences

A controllable diastereoselective C(sp2)-C(sp3) Negishi coupling reaction of secondary benzylic zinc reagents with aryl bromides has been demonstrated for the first time, forming medicinally important 1-arylphenylethylamines. In the presence of Pd(OAc) 2 and S-phos, open-chain (2-amido-1-phenylethyl)zinc reagents bearing a -NHAc or NHCHO group underwent cross-coupling reaction to give syn 1-arylphenylethylamine as the major products, whereas the zinc reagents bearing a sterically hindered-NHCOC(CH3)2 OTBS group specifically yielded anti 1-arylphenylethylamines.

关键词： stereoselective Negishi coupling benzylic zinc 1-arylphenylethylamine aryl bromide