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Promoting Ethylene (co)Polymerization in Aliphatic Hydrocarbon Solvents Using tert-Butyl Substituted Nickel Catalysts

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Chinese Journal of Chemistry 2022年第2期40卷 215-222页

作者： ao chen Daohong Liao Changle chen Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Soft Matter ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China

In the past few decades,the development of high-performance catalysts has been a key driving force and a center of research efforts in the field of olefin ***,a major discrepa ncy exists between in dustrial researches which utilize aliphatic hydrocarb on solventsz and academic researches which predominantly focus the catalytic properties in aromatic *** this con-tribution,a novel diaryl-methyl aniline bearing eight tert-butyl groups was prepared and subsequently transformed to four different kinds of imine-type *** corresponding nickel complexes as well as their counterparts derived from diphenyl-methyl aniline without the tert-butyl groups were prepared and investigated in ethylene polymerization.

关键词： Ethylene polymerization Polyethylene Nickel Solvent effects Steric hindranee

Quantum Algorithm for Boolean Equation Solving and Quantum Algebraic Attack on Cryptosystems

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Journal of Systems Science & Complexity 2022年第1期35卷 373-412页

作者： chen Yu-ao Gao x.ao-Shan Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

This paper presents a quantum algorithm to decide whether a Boolean equation system F has a solution and to compute one if F does have solutions with any given success *** runtime complexity of the algorithm is polynomial in the size of F and the condition number of certain Macaulay matrix associated with *** a consequence,the authors give a polynomial-time quantum algorithm for solving Boolean equation systems if their condition numbers are polynomial in the size of *** authors apply the proposed quantum algorithm to the cryptanalysis of several important cryptosystems:The stream cipher Trivum,the block cipher AES,the hash function SHA-3/Keccak,the multivariate public key cryptosystems,and show that they are secure under quantum algebraic attack only if the corresponding condition numbers are *** leads to a new criterion for designing such cryptosystems which are safe against the attack of quantum computers:The corresponding condition number.

关键词： Block cipher AES Boolean equation solving condition number hash function SHA3/Keccak HHL algorithm MPKC polynomial system solving quantum algorithm stream cipher Trivum

副干酪乳酪杆菌HNU502和粪菌移植缓解抗生素副作用的机制

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食品科学 2025年第3期46卷 1-10页

作者：陈琳李敖黎嘉和张增张家超海南大学食品科学与工程学院海南海口570228

抗生素能够有效治疗细菌感染,但是会使肠道菌群紊乱,从而引起腹泻、胀气和消化不良等副作用。益生菌和粪菌移植(fecal microbiota transplantation,FMT)因具有恢复肠道菌群平衡并缓解各种病症的功能引起广泛关注。本实验以常见的抗生素... 详细信息

抗生素能够有效治疗细菌感染,但是会使肠道菌群紊乱,从而引起腹泻、胀气和消化不良等副作用。益生菌和粪菌移植(fecal microbiota transplantation,FMT)因具有恢复肠道菌群平衡并缓解各种病症的功能引起广泛关注。本实验以常见的抗生素头孢噻肟为代表,结合宏基因组学、病理学分析和气相色谱技术开展FMT和益生菌副干酪乳酪杆菌(Lacticaseibacillus paracasei HNU502)缓解抗生素副作用的机制研究。结果表明,FMT通过恢复紊乱的肠道菌群缓解抗生素副作用,而HNU502通过重建肠道菌群平衡发挥作用。FMT和益生菌补充不同程度地改善了肠道菌群组成,并能够防止杯状细胞缺失,增加黏蛋白2和紧密连接蛋白1含量,从而帮助肠道黏膜恢复。这两种手段也能改善短链脂肪酸代谢紊乱,抑制促炎细胞因子白细胞介素(interleukin,IL)-1β、IL-6、肿瘤坏死因子-α和血清尿素氮分泌,有效减少毒力因子的富集。本研究有助于更好地理解人体健康与肠道菌群之间的联系,可为缓解抗生素副作用提供新的治疗方案,对于改善患者健康状况和生活质量具有现实意义。

关键词：抗生素粪菌移植副干酪乳酪杆菌HNU502 肠道菌群

Mitigating quantum errors via truncated Neumann series

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Science China(Information Sciences) 2023年第8期66卷 92-102页

作者： Kun WANG Yu-ao chen xin WANG Institute for Quantum Computing Baidu Research

Quantum gates and measurements on quantum hardware are inevitably subject to hardware imperfections that lead to quantum errors. Mitigating such unavoidable errors is crucial to explore the power of quantum hardware better. In this paper, we propose a unified framework that can mitigate quantum gate and measurement errors in computing quantum expectation values utilizing the truncated Neumann *** essential idea is to cancel the effect of quantum error by approximating its inverse via linearly combining quantum errors of different orders produced by sequential applications of the quantum devices with carefully chosen coefficients. Remarkably, the estimation error decays exponentially in the truncated order, and the incurred error mitigation overhead is independent of the system size, as long as the noise resistance of the quantum device is moderate. We numerically test this framework for different quantum errors and find that the computation accuracy is substantially improved. Our framework possesses several vital advantages: it mitigates quantum gate and measurement errors in a unified manner, it neither assumes any error structure nor requires the tomography procedure to completely characterize the quantum errors, and most importantly,it is scalable. These advantages empower our quantum error mitigation framework to be efficient and practical and extend the ability of near-term quantum devices to deliver quantum applications.

关键词： near-term quantum devices quantum error mitigation quantum computing

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Microscopic dynamic observation of adhesion hysteresis friction and exploration of the influence of different pressures on friction transmission

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Friction 2021年第4期9卷 758-773页

作者： Cun-ao FENG De-kun ZHANG Kai chen School of Mechatronic Engineering China University of Mining and TechnologyXuzhou 221116China Department of Mechanical Engineering University of British Columbia Vancouver V6T1Z4Canada School of Materials Science and Engineering China University of Mining and Technology Xuzhou 221116China

The mechanism of adhesive friction between viscoelastic materials is a key *** this study,the friction process of the adhesive interface between a friction lining and a wire rope is dynamically observed in real time to analyze the adhesion hysteresis friction intuitively and *** adhesion is determined by the state of motion,while the relative displacement of the wire rope and lining is used to find the magnitude of the adhesive *** hysteresis friction is reflected by the internal deformation of the *** magnitude of the hysteresis friction is determined by the displacement difference(Ax)in the sliding direction of two marked points at different distances from the contact *** results show that the adhesion friction is proportional to the loss modulus and the hysteresis friction is proportional to the ratio of the loss modulus to the square of the storage modulus(E"/(E'^(2))).The frictional vibration first decreases and then increases with the increase in *** K25 lining has the highest adhesion hysteresis friction and minimal frictional *** result provides a simple and intuitive method for research into the friction transmission and vibration of viscoelastic materials.

关键词： adhesion hysteresis friction viscoelasticity frictional vibration dynamic monitoring

Polyolefin vitrimers bearing acetoacetate functionality

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Science China Chemistry 2024年第11期67卷 3861-3867页

作者： Zihao Wang Yue Liu Wenmin Pang ao chen Min chen Chinese Academy of Sciences(CAS)Key Laboratory of Soft Matter Chemistry Department 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 UniversityHefei 230601China

Polyolefin vitrimers are polymer networks bearing reversible covalent crosslinking points, enabling them to be reprocessed and recycled. In this contribution, a series of polyolefin vitrimers were designed based on the acetoacetate-functionalized polyolefin copolymers, which were produced through the direct copolymerization of ethylene with polar comonomers using a phosphinesulfonate palladium catalyst. The pendant acetoacetate group could mediate several characteristic reactions, such as the Michael addition reaction, ketone-amine condensation and metal coordination reaction. As such, structurally adjustable polyolefin vitrimers can be accessed by introducing various dynamic crosslinking bonds, including disulfide exchange, transamination of vinylogous urethane and labile metal coordination bond. The utilization of different crosslinking reactions and the mole ratio of crosslinkers significantly impact the material properties of the resultant polymers. Specifically, the generated polyolefin vitrimers demonstrated excellent reprocessability and closed-loop recycling properties. The study in this work provides an efficient strategy to access various polyolefin vitrimers.

关键词： polyolefin vitrimers acetoacetate group polar monomer olefin copolymerization

Anchorage properties at the interface between soil and roots with branches

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Journal of Forestry Research 2017年第1期28卷 83-93页

作者： x.aodong Ji Lihua chen ao Zhang Key Laboratory of Soil and Water Conservation and Desertification Combating Ministry of Education of ChinaBeijing Forestry University100083 BeijingChina

Roots play an important role in stabilizing and strengthening soil. This article aims to study the mechanical properties of the interface between soil and roots with branches, using the pullout test method in the laboratory. The mechanical properties of the soil-root with branches interface is determined through the pullout-force and root-slippage curve （F-S curve）. The results of investigating 24 Pinus tabulaeformis single roots and 55 P. tabulaeformis roots with branches demonstrated three kinds of pullout test failures： breakage failure on branching root, breakage failure on branching node, and pullout failure. The branch angle had a remarkable effect on the failure mode of the roots with branches： the maximum pullout force increased with the sum of the branch diameters and the branch angle. The peak slippage and the initial force had a positive correlation with the sum of the branch diameter. The sig- nificance test of correlation between branch angle and the initial force, however, showed they had no correlation. Branch angle and branch root diameter affect the anchorage properties between root system and soil. Therefore, it is important to investigate the anchorage mechanics of the roots with branches to understand the mechanism of root reinforcement and anchorage.

关键词： Root-soil interface mechanics Pullout test method Root branches Branch angle

A Fast Product of Conditional Reduction Method for System Failure Probability Sensitivity Evaluation

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Computer Modeling in Engineering & Sciences 2020年第12期125卷 1159-1171页

作者： Jie Yang Changping chen ao Ma School of Marine and Civil Engineering Dalian Ocean UniversityDalian116023China Liaoning Provincial Key Laboratory of Coastal Engineering Dalian Ocean UniversityDalian116023China

Systemreliability sensitivity analysis becomes difficult due to involving the issues of the correlation between failure modes whether using analytic method or numerical simulation methods.A fast conditional reduction method based on conditional probability theory is proposed to solve the sensitivity analysis based on the approximate analytic *** relevant concepts are introduced to characterize the correlation between failure modes by the reliability index and correlation coefficient,and conditional normal fractile the for the multi-dimensional conditional failure analysis is proposed based on the two-dimensional normal distribution *** the calculation of system failure probability can be represented as a summation of conditional probability terms,which is convenient to be computed by iterative solving *** the system sensitivity solution is transformed into the derivation process of the failure probability correlation coefficient of each failure *** examples results show that it is feasible to apply the idea of failure mode relevancy to failure probability sensitivity analysis,and it can avoid multi-dimension integral calculation and reduce complexity and *** with the product of conditional marginalmethod,a wider value range of correlation coefficient for reliability analysis is confirmed and an acceptable accuracy can be obtained with less computational cost.

关键词： Probability of failure sensitivity approximate analytical method correlation coefficient conditional marginal method

Positional Electronic Effects in Iminopyridine-N-oxide Nickel Catalyzed Ethylene Polymerization

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Chinese Journal of Chemistry 2021年第6期39卷 1683-1689页

作者： Mingjun Chi ao chen Wenmin Pang chen Tan Changle chen CAS 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 ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefeiAnhui 230026China

A series of dibenzhydryl-based iminopyridine-N-oxide ligands bearing a range of electron-donating or-withdrawing substituents(OMe,H;and NO_(2))and corresponding nickel pre-catalysts are prepared and *** substituents are installed at different positions on the ligand structure,including 4-position of the pyridine-N-oxide moiety(position x)and 4-position of the aniline moiety(position Y).These nickel pre-catalysts are highly active in ethylene polymerization with the addition of very little amount of aluminum cocatalysts,leading to the formation of polyethylenes with molecular weights of well above one ***-donating substituents make the catalysts sensitive to polymerization *** contrast,the catalysts bearing electron-withdrawing NO_(2) substituents show relatively steady performances at different *** importantly,we demonstrate that different substituents and different positions both play important roles in determining the properties of nickel *** provides an alternative strategy for the future design of high-performance polymerization catalyst.

关键词： Ethylene Polymerization Nickel lminopyridine-N-oxide Substituent effects