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Synthesis of Axially Chiral Anilides Enabled by a Palladium/Ming-Phos-Catalyzed Desymmetric Sonogashira Reaction

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Chinese Journal of Chemistry 2022年第3期40卷 317-322页

作者： Bin yang junfeng yang Junliang Zhang Deportment of Chemistry Fudon University2005 Songhu RoadShanghai 200438China

Atropisomeric anilides are one of important C-N axially chiral *** with the A/-terminal functionalization to prepare such compounds,C-terminal functionalization strategies have been rarely *** describe herein an efficient synthesis of axially chiral anilides enabled by Pd-catalyzed desymmetric Sonogashira cross-coupling reactions with the use of a newly identified *** to high yields with high enantioselectivities(up to 98%ee)were obtained.

关键词： Atropisomerism Axially chiral anilides SadPhos Desymmetrization Sonogashira cross-coupling Kinetic resolution

Applications of gauge duality in robust principal component analysis and semidefinite programming

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Science China Mathematics 2016年第8期59卷 1579-1592页

作者： MA ShiQian yang junfeng Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Department of Mathematics Nanjing University

Gauge duality theory was originated by Preund （1987）, and was recently further investigated by Friedlander et al. （2014）. When solving some matrix optimization problems via gauge dual, one is usually able to avoid full matrix decompositions such as singular value and/or eigenvalue decompositions. In such an approach, a gauge dual problem is solved in the first stage, and then an optimal solution to the primal problem can be recovered from the dual optimal solution obtained in the first stage. Recently, this theory has been applied to a class of semidefinite programming （SDP） problems with promising numerical results by Friedlander and Mac^to （2016）. We establish some theoretical results on applying the gauge duality theory to robust principal component analysis （PCA） and general SDP. For each problem, we present its gauge dual problem, characterize the optimality conditions for the primal-dual gauge pair, and validate a way to recover a primal optimal solution from a dual one. These results are extensions of Friedlander and Macedo （2016） from nuclear norm regularization to robust PCA and from a special class of SDP which requires the coefficient matrix in the linear objective to be positive definite to SDP problems without this restriction. Our results provide further understanding in the potential advantages and disadvantages of the gauge duality theory.

关键词： gauge optimization gauge duality polar function antipolar set singular value decomposition robust principal component analysis semidefinite programming

Solution set on the natural satellite formation orbits under first-order earth's non-spherical perturbation

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Acta Mechanica Sinica 2005年第5期21卷 503-510页

作者： Humei Wang Wei yang junfeng Li School of Aerospace Tsinghua University Beijing100084 China

Using the reference orbital element approach, the precise governing equations for the relative motion of formation flight are formulated. A number of ideal formations with respect to an elliptic orbit can be designed based on the relative motion analysis from the equations. The features of the oscillating reference orbital elements are studied by using the perturbation theory. The changes in the relative orbit under perturbation are divided into three categories, termed scale enlargement, drift and distortion respectively. By properly choosing the initial mean orbital elements for the leader and follower satellites, the deviations from originally regular formation orbit caused by the perturbation can be suppressed. Thereby the natural formation is set up. It behaves either like non-disturbed or need little control to maintain. The presented reference orbital element approach highlights the kinematics properties of the relative motion and is convenient to incorporate the results of perturbation analysis on orbital elements. This method of formation design has advantages over other methods in seeking natural formation and in initializing formation.

关键词： Orbital mechanics . Satellite formation flight .Orbital elements . Reference orbital elements . Perturbation

Effect of Mixed Dispersants on Suppression of the Gel Effect during Aqueous Adiabatic Terpolymerization of AM,NaAA,and DMC

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China Petroleum Processing & Petrochemical Technology 2023年第3期25卷 83-91页

作者： yang junfeng Zhou Manli Wang Meng Qingyuan Yakoo Chemical Co. LtdQingyuan 510640China Department of Polymer Science and Engineering South China University of TechnologyGuangzhou 510640China

Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleate (Span80) and polyoxyethylene sorbitan monooleate (Tween 80) were introduced to the terpolymerization system in an attemptto mitigate the gel effect. This enabled the preparation of high-performance amphoteric polyacrylamides, which werecharacterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The influences of the dispersanttype and content as well as the hydrophilic-lipophilic balance (HLB) on the gel effect were examined, and the mechanismunderlying the suppression of the gel effect was considered. The obtained results indicated that the gel effect can beeffectively mitigated using an aqueous adiabatic terpolymerization system containing mixed Span 80/Tween 80 dispersantsat various contents. In particular, mixed dispersant contents of 0.6%–0.8% with HLB values of 5.0–6.0 afforded the optimalperformance (e.g., high viscosity, fast aqueous dissolution time, and the like).

关键词： gel effect dispersants amphoteric polyacrylamide terpolymerization

A COMPARISON OF DIFFERENT CONTRACTION METHODS FOR MONOTONE VARIATIONAL INEQUALITIES

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Journal of Computational Mathematics 2009年第4期27卷 459-473页

作者： Bingsheng He Xiang Wang junfeng yang Department of Mathematics Nanjing University Nanjing 210093 China

It is interesting to compare the efficiency of two methods when their computational loads in each iteration are equal. In this paper, two classes of contraction methods for monotone variational inequalities are studied in a unified framework. The methods of both classes can be viewed as prediction-correction methods, which generate the same test vector in the prediction step and adopt the same step-size rule in the correction step. The only difference is that they use different search directions. The computational loads of each iteration of the different classes are equal. Our analysis explains theoretically why one class of the contraction methods usually outperforms the other class. It is demonstrated that many known methods belong to these two classes of methods. Finally, the presented numerical results demonstrate the validity of our analysis.

关键词： Monotone variational inequalities Prediction-correction Contraction methods.

Responses of zonal wind at -40°N to stratospheric sudden warming events in the stratosphere, mesosphere and lower thermosphere

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Science China(Technological Sciences) 2017年第6期60卷 935-945页

作者： yang junfeng XIAO CunYing HU Xiong XU QingChen National Space Science Center Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

Based on the data at^40°N at different longitudes during different stratospheric sudden warming(SSW)events,the responses of zonal winds in the stratosphere,mesosphere and lower thermosphere to SSWs are studied in this *** variations of zonal wind over Langfang,China(39.4°N,116.7°E)by MF radar and the modern era retrospective-analysis for research and applications(MERRA)wind data during 2010 and 2013 SSW and over Fort Collins,USA(41°N,105°W)by lidar and MERRA wind data during 2009 SSW are *** show that the zonal wind at^40°N indeed respond to the SSWs while different specifics are found in different SSW events or at different *** zonal wind has significant anomalies during the *** Langfang,before the onset of 2010 and 2013 SSW,the zonal wind reverses from eastward to westward below about 60–70 km and accelerates above this region,while westward wind prevails from 30 to 100 km after the onset of2010 SSW,and westward wind prevails in 30–60 and 85–100 km and eastward wind prevails in 60–85 km after the onset of2013 *** Fort Collins during 2009 SSW,eastward wind reverses to westward in 20–30 km before the onset while westward wind prevails in 20–30 and 60–97 km and eastward wind prevails in 30–60 and in 97–100 km after the ***,simulations by the specified dynamics version of the whole atmosphere community climate model(SD-WACCM)are taken to explain different responding specifics of zonal wind to SSW *** is found that the modulation of planetary wave(PW)plays the main *** phases of PWs would lead to the different zonal wind along with longitudes and the different amplitudes and phases in different SSW events can lead to the different zonal wind responses.

关键词： stratospheric sudden warming(SSW) MF radar WACCM planetary waves

湖南柑橘产区镉污染状况及镉对柑橘发育影响分析

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园艺学报 2025年第1期52卷 200-212页

作者：杨金磊吕壁纹陈岳文金燕杨俊枫周铁唐俊常媛媛杨长耀卢晓鹏湖南农业大学园艺学院/国家柑橘改良中心长沙分中心长沙410128 湖南省农业科学院园艺研究所长沙410125 邵阳市农业科学研究院湖南邵阳422001

通过调查湖南柑橘产区受镉污染的情况,结合盆栽处理研究土壤镉污染对柑橘树体生长发育的影响,以期为镉污染防治提供理论依据。分析了湖南省柑橘主产区及长沙—株洲—湘潭(长株潭)地区果园土壤pH、有机质、镉含量,并评价‘橘湘早’温州... 详细信息

通过调查湖南柑橘产区受镉污染的情况,结合盆栽处理研究土壤镉污染对柑橘树体生长发育的影响,以期为镉污染防治提供理论依据。分析了湖南省柑橘主产区及长沙—株洲—湘潭(长株潭)地区果园土壤pH、有机质、镉含量,并评价‘橘湘早’温州蜜柑、‘纽荷尔’脐橙果实镉含量;以1.0、1.5、3.0和10.0 mg·kg^(-1)的CdCl_(2)·2H_(2)O用量处理3年生盆栽‘橘湘早’和‘纽荷尔’植株,测定生理生化指标的变化;以柑橘常用砧木枳和卡里佐枳橙水培实生苗为材料,用50 mg·L^(-1)的CdCl_(2)·2H_(2)O溶液进行镉胁迫,观察其对镉的耐受情况。共采集湖南省不同地区柑橘果园土壤样品278份(柑橘主产区201份,长株潭地区77份),测定结果显示,70.5%果园土壤样品的pH茎、叶>果肉;长期镉胁迫后树体受伤害明显,镉胁迫处理180 d叶片丙二醛、脯氨酸含量和过氧化物酶活性大幅升高。镉胁迫处理(50 mg·L^(-1) CdCl_(2)·2H_(2)O)砧木实生苗20 d后,枳叶片发红、脱落,而枳橙与对照无明显差异。综上,湖南省内柑橘主产区绝大多数果园土壤未受到镉污染,长株潭地区果园土壤镉污染严重(土壤镉含量0.30~7.46 mg·kg^(-1)),但该地区栽培的柑橘果实镉含量符合食品安全国家标准;柑橘树体的根部是累积镉元素的主要器官,镉向地上部分茎叶和果实的转运效率逐级减弱;砧木卡里佐枳橙较枳表现出较强的镉胁迫耐受性。

关键词：柑橘土壤重金属镉发育

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A real time transmission system of long distance for nuclear logging

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Nuclear Science and Techniques 2011年第6期22卷 366-371页

作者： CAO Ping SONG Kezhu yang junfeng State Key Laboratory of Particle Detection and Electronics Anhui Key Laboratory of Physical Electronics Department of Modern Physics University of Science and Technology of China Hefei 230026 China

Some specified chips in traditional Manchester-Ⅱencoding/decoding designs are used to guarantee strictly the stability of the input wave,otherwise the capacity of anti-interference and resilience are degraded *** this paper,a new Manchester-Ⅱencoding/ decoding system is used for nuclear logging by a 7 000 m armoring cable.A thorough hardware wave tracking decoding algorithm is proposed and realized in a FPGA hardware *** on-site measurements show that this transmission system can decode correctly in real time,with a bit error rate of better than 10^(-10).

关键词：传输系统长距离核测井编码/解码曼彻斯特抗干扰能力抗灾能力解码系统

Nickel-Catalyzed Regio-and Stereoselective Defluorinative Arylation of gem-Difluorinated Cyclopropanes

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Chinese Journal of Chemistry 2024年第8期42卷 823-828页

作者： Shutao Qi Yunkai Hua Liangkai Pan junfeng yang Junliang Zhang Department of Chemistry Fudan University2005 Songhu RoadShanghai200438 China Fudan Zhangjiang Institute Shanghai201203 China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan 453007China

Comprehensive Summary,Herein,we report nickel-catalyzed cross-coupling of gem-difluorinated cyclopropanes with boronic acids,providing the corresponding arylated 2-fluoroallylic *** approach used commercially available phosphine ligand Xantphos to obtain monofluorinated alkenes with high regioselectivity and *** studies proposed a Ni(II)-fluoroallyl pathway and excluded the radical pathway.

关键词： Nickel Monofluoroolefin Cyclopropane Regioselectivity Stereoselectivity C-C coupling Cross-coupling Synthetic methods