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Two new flavonoid diglycosides from Cephalotaxus sinensis

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Chinese Chemical Letters 2007年第7期18卷 837-839页

作者： Wei Li Rong Ji Dai yu hong yu liang Li Wei Wei Meng yu Lin Deng School of Life Science and Technology Beijing Institute of Technology Beijing 100081 China

Two new acetylated flavonoid diglycosides, scutellarein-5-O-[α-L-rhamnopyranosyl-（1 → 4）-β-D-6-O-acetylglucopyranoside]（1）, apigenin-5-O-[α-L-rhamnopyranosyl-（1→ 2）-β-D-3,6-di-O-acetylglucopyranoside] （2）, were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS,^1H-^1H COSY, HSQC and HMBC experiments.

关键词： Cephalotaxus sinensis (Rehd et Wile) Li Flavonoid diglycosides Scutellarein-5-O-[α-L-rhamnopyranosyl-(1→ 4)-β-D-6-O-acetylglucopyranoside] Apigenin-5-O-[α-L-rhamnopyranosyl-(1 → 2)-β-D-3,6-di-O-acetylglucopyranoside]

Spectroscopic Studies on the Interaction of Asiatic Acid with Bovine Serum Albumin

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Chinese Journal of Chemistry 2011年第3期29卷 549-554页

作者： Yao, Di Ni, Shouhai Wen, Maogui Bian, Hedong yu, Qing liang, hong Chen, Zhenfeng Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University) Ministry of Education of China Guilin Guangxi 541004 China

Fluorescence spectroscopy, Fourier transform infrared （FT-IR） spectroscopy, circular dichroism （CD） and FT-Raman spectroscopy were employed to analyze the binding of the asiatic acid （AA） to bovine serum albumin （BSA） under simulative physiological conditions. Fluorescence data revealed that the fluorescence quenching of BSA by AA was the result of the formation of BSA-AA complex. The fluorescence quenching mechanism of BSA by AA was a static quenching procedure. According to the Van＇t Hoff equation, the thermodynamic parameters enthalpy change （△H0） and entropy change （△S0） for the reaction were evaluated to be --12.55 kJ·mol^-1 and 67.08 kJomol 1, respectively, indicating that hydrophobic and electrostatic interactions played a major role in stabilizing the complex. The influence of AA on the conformation of BSA has also been analyzed on the basis of FT-IR, CD and FT-Raman spectra.

关键词： bovine serum albumin asiatic acid secondary structure fluorescence spectroscopy fourier transforminfrared (FT-IR) circular dichroism raman spectroscopy

Wavefront correction of Ti:sapphire terawatt laser with varying precision of phase conjugation between deformable mirror and wavefront sensor

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Chinese Physics B 2012年第1期21卷 192-198页

作者： yu liang-hong liang Xiao-Yan Ren Zhi-Jun Wang Li Xu Yi Lu Xiao-Ming yu Guo-Hao State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Joint Laboratory of High Power Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

The phase conjugation between the deformable mirror and the wavefront sensor in the aberration correction of a terawatt Ti：sapphire laser is studied experimentally and theoretically in this paper. At varying values of phase- conjugation precision, we focus the corresponding beams into spots of the same size of 5.1 μm × 5.3 μm with a f/4 parabola in the 32 TW/36 fs Ti：sapphire laser system. The results show that the precision of conjugation can induce an intensity modulation but does not significantly affect the wavefront correction.

关键词： adaptive optics wave front correction phase conjugation deformable mirror

Efficient Spherical Wavefront Correction near the Focus for the 0.89 PW/29.0 fs Ti:Sapphire Laser Beam

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Chinese Physics Letters 2011年第2期28卷 85-88页

作者： REN Zhi-Jun liang Xiao-Yan yu liang-hong LU Xiao-Ming LENG yu-Xin LI Ru-Xin XU Zhi-Zhan State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800

We demonstrate a new loop system of the spherical wavefront(SW)correction near the beam focus to effectively improve the focusability of 0.89 PW/29.0 fs Ti:sapphire chirped pulse amplification *** wavefront correction,the Strehl ratio is improved to reach 0.91,and the focal spot size using the f/4 off-axis parabola is reduced to 6.34 x 6.94μm^(2)(corresponding to 1.63 x 1.78 times diffraction limitation).With full peak power of 0.89 PW,the peak intensity of 2.59 x 10^(21)W/cm^(2)is *** experimental results show that the SW correction scheme near the beam focus is comparatively simple,economic and high-efficient.

关键词： correction beam spherical

Concerted Steric and Electronic Strategy in Thermostable Salicylaldiminato Nickel Catalysts for Ethylene(Co)polymerization

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Chinese Journal of Polymer Science 2024年第8期42卷 1085-1092页

作者： hong-yu Ji hong-liang Mu Chun-Feng Tang yu-Xing Zhang yue Chi Zhong-Bao Jian Key Laboratory of Advanced Structural Materials Ministry of EducationSchool of Materials Science and EngineeringChangchun University of TechnologyChangchun 130012China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

Olefin polymerization is one of the most im portant chemical reactions in *** work presents a strategy that emphasizes the synergistic meta/poro-steric hindrance of N-aryl groups and electronic effects in newly synthesized neutral salicylaldiminato nickel *** nickel(Ⅱ)catalysts exhibit exceptional thermostability,ranging from 30℃to 130℃,demonstrating enhanced catalytic activities and broadly regulated polyethylene molecular weights(3-341 kg·mol^(-1))and controlled polymer branch density(2-102 brs/1000C).The preferred catalyst Ni3 with concerted steric and electronic effects enables the production of solid-state semi-crystalline polyethylene materials at temperatures below 90℃.Notably,Ni3 exhibits an impressive tolerance of 110℃and can withstand even the challenging polymerization temperature of 130℃,leading to the production of polyethylene wax and ***,functionalized polyethylene is produced.

关键词： Polyolefin Salicylaldiminato ligand Nickel catalyst Oil Wax

The influence of medium on the stability of coordination compounds *** system In(tiron)^--NaClO_4-C_2H_5OH-H_2O

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Chinese Journal of Chemistry 1992年第2期10卷 122-129页

作者： GUO,yu-hong liang,Chun-yu LIU,Qi-Tao Department of Chemistry,Liaoning University,Shenyang 110036 Department of Chemistry Liaoning University Shenyang 110036

The stability constants of complex anion In(tiron)^-in mixed solvents of ethanol-water with weight percentages of ethanol being 0,5,15,25,35 and 50 have been measured spectrophotometrically at 293 K,using NaClO_4 as supporting electrolyte with ionic strength ranging from 0.1 to 3.3mol·dm^(-3). The thermodynamic stability constants of In(tiron)^-in various mixed solvents have been obtained by a polynomial approximation equation based on Pitzer's *** a comparison,the traditional Debye-Hückel equation has also been used to treat the same *** results show that this polynomial approximate method is obviously superior to the old *** was discovered that there is a linear rela- tion between the thermodynamic stability constants of In(tiron)^-and the mole fraction of organic component in mixed solvents or the reciprocal of dielectric constants of mixed *** medium effect and the standard free energy of transfer,ΔG_(tr)~0,for the coordination reaction:In^(3+)+tiron^(4-)= In(tiron)^-,have also been discussed.

关键词： ab NaClO4-C2H5OH-H2O OH

Enhancing cut selection through reinforcement learning

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Science China Mathematics 2024年第6期67卷 1377-1394页

作者： Shengchao Wang liang Chen Lingfeng Niu yu-hong Dai Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing100190China Research Center on Fictitious Economy and Data Science Chinese Academy of SciencesBeijing100190China

With the rapid development of artificial intelligence in recent years,applying various learning techniques to solve mixed-integer linear programming(MILP)problems has emerged as a burgeoning research *** from constructing end-to-end models directly,integrating learning approaches with some modules in the traditional methods for solving MILPs is also a promising *** cutting plane method is one of the fundamental algorithms used in modern MILP solvers,and the selection of appropriate cuts from the candidate cuts subset is crucial for enhancing *** to the reliance on expert knowledge and problem-specific heuristics,classical cut selection methods are not always transferable and often limit the scalability and generalizability of the cutting plane *** provide a more efficient and generalizable strategy,we propose a reinforcement learning(RL)framework to enhance cut selection in the solving process of ***,we design feature vectors to incorporate the inherent properties of MILP and computational information from the solver and represent MILP instances as bipartite ***,we choose the weighted metrics to approximate the proximity of feasible solutions to the convex hull and utilize the learning method to determine the weights assigned to each ***,a graph convolutional neural network is adopted with a self-attention mechanism to predict the value of weighting ***,we transform the cut selection process into a Markov decision process and utilize RL method to train the *** experiments are conducted based on a leading open-source MILP solver *** on both general and specific datasets validate the effectiveness and efficiency of our proposed approach.

关键词： reinforcement learning mixed-integer linear programming cutting plane method cut selection

High-precision X-ray polarimeter based on channel-cut crystals

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Nuclear Science and Techniques 2024年第3期35卷 30-39页

作者： Shang-yu Si Zhong-liang Li Wen-hong Jia Lian Xue hong-Xin Luo Jian-Cai Xu Bai-Fei Shen Lin-Gang Zhang liang-liang Ji yu-Xin Leng Ren-Zhong Tai Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China

We report on using synthetic silicon for a high-precision X-ray polarimeter comprising a polarizer and an analyzer,each based on a monolithic channel-cut crystal used at multiple Brewster reflections with a Bragg angle very close to 45°.Experiments were performed at the BL09B bending magnet beamline of the Shanghai Synchrotron Radiation Facility using a Si(800)crystal at an X-ray energy of 12.914 keV.A polarization purity of 8.4×10^(-9)was *** result is encouraging,as the measured polarization purity is the best-reported value for the bending magnet ***,this is the firstly systematic study on the hard X-ray polarimeter in China,which is crucial for exploring new physics,such as verifying vacuum birefringence.

关键词： X-ray polarimeter Vacuum birefringence Synchrotron radiation Channel-cut crystal

Synthesis, Crystal Structure and Spectroscopic Properties of Cyanide-bridged Complex [RuⅡ（ttpy）（CN）3MnⅢ（salen）]

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Chinese Journal of Structural Chemistry 2019年第5期38卷 745-753,669页

作者： SUN Gui-Fang LI Jia-Qi yu hong-liang yu Meng PENG Pei DING Wen-Wen WANG Yong Hubei Key Laboratory of Drug Synthesis and Optimization Jingchu University of Technology

Tricyanide building block K[Ru(ttpy)(CN)3] and [MnⅢ(salen)](ClO4) have been used to design and synthesize a heterobimetallic one-dimensional(1D) zigzag chain complex 1,[RuⅡ(ttpy)(CN)3 MnⅢ(salen)](ttpy = 4′-(p-tolyl)-2,2′:6′,2″-terpyridine, salen = N,N?-ethylenebis-(salicylideneaminato)dianion). Single-crystal X-ray diffraction analysis shows complex 1 crystallizes in orthorhombic Pbca space group and the asymmetric unit of 1 contains one[-NC-RuⅡ(ttpy)(CN)(m-CN)-Mn Ⅲ-(salen)-] molecule. In the structure of 1, each [Ru Ⅱ(ttpy)(CN)3]-connects two [MnⅢ(salen)]+ with two cyanide groups in a cis-conformation, and in turn each[MnⅢ(salen)]+ unit links two [RuⅡ(ttpy)(CN)3]-building blocks in a trans-conformation, resulting in a 1D [-NC-RuⅡ-CN-MnⅢ-]n chain. Furthermore, the electronic absorption spectra and luminescence spectroscopy of complex 1 have also been studied.

关键词： cyanide-bridged crystal structure Ru(Ⅱ) spectroscopic properties Mn(Ⅲ)