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Influence of chelate ring size on the properties of phosphine-sulfonate palladium catalysts

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Science China Chemistry 2018年第9期61卷 1175-1178页

作者： chen zou Wenmin Pang Changle chen CAS Key Laboratory of Soft Matter Chemistry i Ch EM (Collaborative Innovation Center of Chemistry for Energy Materials) Department of Polymer Science and Engineering University of Science and Technology of China

Phosphine-sulfonate based palladium is one of the most extensively studied catalyst systems in olefin *** type of catalyst features six-membered chelate ring size,and can enable the copolymerizations of ethylene with a wide variety of polar *** this contribution,we decide to investigate the influence of chelate ring size on the properties of phosphinesulfonate palladium *** such,a series of phosphine-sulfonate ligands and the corresponding seven-membered ring Pd(II)complexes[κ~2-(P,O)-2-(CH_2-PR_1R_2)-4-methylphenyl-sulfonato]Pd(Me)(DMSO)(Pd1,R_1=R_2=Cy,Pd2,R_1=R_2=o-Me O-C_6H_4;Pd3,R_1=Ph,R_2=2-[2,6-(Me O)_2C_6H_3]C_6H_4;DMSO=dimethyl sulfoxide)were designed,prepared and *** palladium complexes are moderately active when they were applied in ethylene polymerization and copolymerizations with methyl acrylate and butyl vinyl ***,their properties are greatly reduced from those of the classic six-membered ring phosphine-sulfonate palladium complex Pd2′.The experimental results indicate that the bigger chelate ring size can increase the ligand flexibility and damage the catalytic properties for the phosphine-sulfonate type palladium catalysts.

关键词： ethylene polymerization polar monomer chelate ring size phosphine-sulfonate palladium catalysts

Styrene-containing Phosphine-sulfonate Ligands for Nickel-and Palladium-catalyzed Ethylene Polymerization

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Chinese Journal of Polymer Science 2021年第4期39卷 447-454,I0006页

作者： Shabnam Behzadi chen zou Bang-Pei Yang chen Tan Chang-Le chen Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei230026China

A series of phosphine-sulfonate ligands bearing 2-,3-and 4-vinylphenyl on the phosphorus atom were designed,synthesized,characterized and investigated in Ni-and Pd-catalyzed ethylene *** structure of the phosphine-sulfonate Pd complex bearing 2-vinylphenyl on the phosphorus atom showed 2,1-insertion for the 2-vinyl *** phosphine-sulfonate Ni complex bearing 2-vinylphenyl resulted in significantly increased thermal stability and polyethylene molecular weights(Mn=3.69×10^(4)g·mol^(-1) at 80℃)versus the counterparts bearing 3-/4-vinyl groups as well as previously reported phosphine-sulfonate Ni complexes bearing bulky biaryl substituents.

关键词： Phosphine-sulfonate Ethylene polymerization Steric effect Palladium Nickel

Early Screening of Ovarian Cancer

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 463-474页

作者： Xiao HAN chen-chen zou Xiang-zhong FANG School of Mathematical Sciences Peking Unviersity School of Mathematics and Statistics Qingdao Unviersity

The mortality of ovarian cancer is higher than any other female genital malignant tumors, while there exists a strong correlation between early-stage detection and cure for it. CA125 and HE4 are two most common and effective serum markers in recent screening research of ovarian cancer. This paper derives a sequential screening strategy for ovarian cancer by jointly modeling the longitudinal profiles of CA125 and HE4. We construct a Bayesian hierarchical mixture model with changepoint, and propose two approaches for diagnosis： the risk of cancer index and the hypothesis test on the true incidence time. We simulated a 7-year sequential screening research and compared with the standard approach based on a fixed cutoff level. Our approach achieves a 15% higher sensitivity for a fixed specificity, indicating that the sequential strategy combining multiple markers is more effective in the early-stage detection of ovarian cancer.

关键词： longitudinal hierarchical MCMC ovarian caner sequential screening

A general cocatalyst strategy for performance enhancement in nickel catalyzed ethylene(co)polymerization

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Chinese Chemical Letters 2022年第9期33卷 4363-4366页

作者： Quan Wang Zhao Zhang chen zou Changle chen CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

The tuning of olefin-polymerization catalyst properties through ligand modifications is efficient but requires complicated and costly *** this contribution,a simple Bu_(2)Mg-based cocatalyst strategy is designed that can simultaneously enhance the catalytic properties(activity,thermal stability,polymer molecular weight,branching density,melting point,etc.)of various nickel catalysts(α-diimine nickel,pyridine imine nickel and iminopyridine-N-oxide nickel)in ethylene polymerization,and enable great product morphology *** example,a simpleα-diimine nickel catalyst can demonstrate polymerization activity of up to 1.29×10^(7)g mol^(−1)h^(−1)and molecular weight of up to 1.90×10^(6)g/mol in the presence of Bu_(2)Mg *** resulting polyethylenes exhibit excellent mechanical properties,with tensile stress of up to 47.4 MPa and strain of up to 1020%.This cocatalyst strategy is generally applicable to different nickel catalysts,and can lead to property enhancement in ethylene copolymerization with a series of polar comonomers such as methyl 10-undecylenate,10-undecylenic acid and 10-undecenol.

关键词： Nickel Cocatalyst Magnesium Ethylene polymerization

TIME ASYMPTOTIC BEHAVIOR OF THE BIPOLAR NAVIER-STOKES-POISSON SYSTEM

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Acta Mathematica Scientia 2009年第6期29卷 1721-1736页

作者： Hai-Liang Li Tong Yang chen zou Department of Mathematics Capital Normal University Beijing 100048 China Department of Mathematics City University of Hong Kong 83 Tat Chee Avenue Kowloon Hong Kong Department of Mechanics and Aerospace Engineering COE Peking University Beijing 100871 China

The bipolar Navier-Stokes-Poisson system （BNSP） has been used to simulate the transport of charged particles （ions and electrons for instance） under the influence of electrostatic force governed by the self-consistent Poisson equation. The optimal L^2 time convergence rate for the global classical solution is obtained for a small initial perturbation of the constant equilibrium state. It is shown that due to the electric field, the difference of the charge densities tend to the equilibrium states at the optimal rate （1 ＋ t）^-3/4 in L^2-norm, while the individual momentum of the charged particles converges at the optimal rate （1 ＋ t）^-1/4 which is slower than the rate （1 ＋ t）^-3/4 for the compressible Navier-Stokes equations （NS）. In addition, a new phenomenon on the charge transport is observed regarding the interplay between the two carriers that almost counteracts the influence of the electric field so that the total density and momentum of the two carriers converges at a faster rate （1 ＋ t）^-3/4＋ε for any small constant ε 〉 0. The above estimates reveal the essential difference between the unipolar and the bipolar Navier-Stokes-Poisson systems.

关键词： bipolar Navier-Stokes-Poisson system optimal time convergence rate spectrum analysis total momentum

Potentially Practical Catalytic Systems for Olefin-Polar Monomer Coordination Copolymerization

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CCS Chemistry 2024年第4期6卷 882-897页

作者： chen Tan Min chen chen zou Changle chen Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Environment-Friendly Polymeric Materials of Anhui ProvinceAnhui UniversityHefeiAnhui 230601 CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026

Studies on transition-metal catalyzed olefin-polar monomer coordination copolymerization and their resulting polar-functionalized polyolefin materials have attracted attention from both academia and *** decades of research,recent developments in a variety of high-performance catalytic systems have shown that this field is on the brink of *** review summarizes representative olefin-polar monomer coordination copolymerization catalyst systems that may be suitable for industrial polyolefin production via homogeneous solution-phase processes or heterogeneous gas-phase/slurry-phase processes.

关键词： olefin copolymerization polar monomer catalyst solution polymerization heterogeneous

Energy-efficient and security-optimized AES hardware design for ubiquitous computing

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Journal of Systems Engineering and Electronics 2008年第4期19卷 652-658页

作者： chen Yicheng zou Xuecheng Liu Zhenglin Han Yu Zheng Zhaoxia Dept. of Electronic Science and Technology Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

Ubiquitous computing must incorporate a certain level of security. For the severely resource constrained applications, the energy-efficient and small size cryptography algorithm implementation is a critical problem. Hardware implementations of the advanced encryption standard （AES） for authentication and encryption are presented. An energy consumption variable is derived to evaluate low-power design strategies for battery-powered devices. It proves that compact AES architectures fail to optimize the AES hardware energy, whereas reducing invalid switching activities and implementing power-optimized sub-modules are the reasonable methods. Implementations of different substitution box （S-Boxes） structures are presented with 0.25μm 1.8 V CMOS （complementary metal oxide semiconductor） standard cell library. The comparisons and trade-offs among area, security, and power are explored. The experimental results show that Galois field composite S-Boxes have smaller size and highest security but consume considerably more power, whereas decoder-switch-encoder S-Boxes have the best power characteristics with disadvantages in terms of size and security. The combination of these two type S-Boxes instead of homogeneous S-Boxes in AES circuit will lead to optimal schemes. The technique of latch-dividing data path is analyzed, and the quantitative simulation results demonstrate that this approach diminishes the glitches effectively at a very low hardware cost.

关键词： encryption and decryption power analysis model inhomogeneous S-Boxes ubiquitous computing advanced encryption standard.

SiO_(2)-Supported Ni(II)and Fe(II)Catalysts Bearing Sodium-Sulfonate Group for Olefin Polymerization

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Chinese Journal of Chemistry 2022年第23期40卷 2773-2779页

作者： Yao Sun Quan Wang Yao Pan Wenmin Pang chen zou Min chen CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Anhui UniversityHefeiAnhui 230601China

Heterogeneous catalysts have been dominant for industrial polyolefin production,offering many distinct advantages,such as controlling the morphology of the polymer and preventing reactor *** this contribution,we designed several types of imine ligands bearing sodium-sulfonate ionic groups and the corresponding nickel/iron *** catalysts could be immobilized on SiO_(2)with strong affinity and high catalyst *** SiO_(2)-supported catalysts behaved better than their homogeneous counterparts during ethylene polymerization with extremely high activity(2.6×10^(4)kg·mol^(−1)·h^(−1))and high thermal *** addition,the supported nickel catalysts generated free-flowing polyethylene with high molecular weight(Mn up to 2.65×10^(3)kg·mol^(–1))and excellent morphology control,indicating no reactor fouling due to the leaching of ***,for copolymerization,immobilized nickel catalysts showed a higher tolerance of polar monomers,and the efficient copolymerization of ethylene with undecylenic acid was achieved with high activity(450 kg·mol^(−1)·h^(−1))and a high incorporation ratio(up to 12.3%).

关键词： Heterogeneous catalysis Nickel iron catalysts Sodium-sulfonate group Polymerization Copolymerization

SYNTHESIS OF CHIRAL CONJUGATED POLYBINAPHTHYLS BY SONOGASHIRA REACTION

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Chinese Journal of Polymer Science 2006年第3期24卷 273-279页

作者：成义祥 Ling-wu chen Xiao-wei zou Jin-feng Song College of Chemistry and Chemical Engineering Nanjing University Nanjing 210093 China

Chiral polymers P-1 and P-2 were synthesized by the polymerization of （R）-3,3＇-diiodo-2,2＇-bisbutoxy-1,1＇- binaphthyl （M- 1 ） with 2,5-di（4-ethynylphenyl）- 1,3,4-oxadiazole （M-3） and （R）-3,3＇-diethylnyl-2,2＇-bisbutoxy- 1,1 ＇-binaphthyl （M-2） with 1,2-di（4-bromophenyl）acetylene （M-4） under Sonogashira reaction, respectively. Both monomers and polymers were analyzed by NMR, MS, FT-IR, UV-Vis spectroscopy, DSC-TGA, fluorescence spectroscopy, GPC and CD spectroscopy. CD spectra of P-1 and P-2 are similar due to the same chiral center units and main chain structure. The long wavelengths CD effect of P-1 and P-2 can be regarded as the more extended conjugated structure and a highly rigid backbone in the polymer chain. Polymers have strong blue fluorescence due to the efficient energy migration from the extended n-electronic structure of the polymers to the chiral binaphthyl core and are expected to provide understanding of the relationship between molecular structure and fluorescent property of the chiral polymers.

关键词： (R)-BINOL Chiral conjugated polymer Sonogashira reaction Fluorescence.