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Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

Science China Chemistry 2025年

作者： Shuai Zhang Pei-Zhi Liu Yan-Bo Li Qi Zhang Jun-Zhao Xiao Yi-fan wang Tian-Yu Wei Jia-Wei Jiang Ye wang Qian Peng Liang Yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

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Catalytic reduction of NO_x by biomass-derived activated carbon supported metals

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Chinese Journal of Chemical Engineering 2018年第10期26卷 2077-2083页

作者： Yun Shu fan Zhang fan wang Hongmei wang Research Center of Air Pollution Control Technology Chinese Research Academy of Environmental Sciences

In this study,to prepare a series of activated carbon-supported metals for the catalytic reduction of NO_x to N_2 in excess O_2,activated carbons derived from lignocellulosic and herbaceous biomasses were selected as the reducing agents,and alkali and transition metals were used as the catalytic active *** effects of the type of biomass,carbonization temperature and catalyst composition on NO_x reduction efficiency were analyzed in a fixed-bed flow *** results showed that two temperature regimes are present for the NO_x-carbon reaction:at temperatures below 250°C,the NO_x adsorption process on the carbon surface was predominant,whereas true NO_x reduction by carbon occurred at temperatures above 250°C,producing N_2,CO_2 and *** influence of the carbonization temperature on carbon reactivity depended on the effect of the carbonization temperature on the carbon surface area and the reduction of the metal species on *** studied metals catalyzed both NO_xand O_2reduction by carbon,and potassium could strongly enhance the C-NO_x reaction without substantial carbon consumption by O_***,the potassium supported by sawdust-derived activated carbon exhibited higher selectivity and capacity towards NO_x reduction than did its previously reported coal-derived *** properties were ascribed to the high dispersion of the active potassium species on the carbon surface,as observed through the comparison of X-ray photoelectron spectroscopy and powder X-ray diffraction results for the carbons made from biomass and coal-based precursors.

关键词： Biomass NOx reduction Activated carbon Selectivity

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Robust adaptive control of hypersonic vehicle considering inlet unstart

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Journal of Systems Engineering and Electronics 2022年第1期33卷 188-196页

作者： wang fan fan Pengfei fan Yonghua XU Bin YAN Jie College of Astronautics Northwestern Polytechnical UniversityXi’an 710072China College of Automation Northwestern Polytechnical UniversityXi’an 710072China

In this paper,a model reference adaptive control(MRAC)augmentation method of a linear controller is proposed for air-breathing hypersonic vehicle(AHV)during inlet *** the development of hypersonic flight technology,hypersonic vehicles have been gradually moving to the stage of *** the maneuvers,changes of attitude,Mach number and the back pressure can cause the inlet unstart phenomenon of *** unstart causes significant changes in the aerodynamics of AHV,which may lead to deterioration of the tracking performance or instability of the control ***,we firstly establish the model of hypersonic vehicle considering inlet unstart,in which the changes of aerodynamics caused by inlet unstart is described as nonlinear ***,an MRAC augmentation method of a linear controller is proposed and the radial basis function(RBF)neural network is used to schedule the adaptive parameters of ***,the Lyapunov function is constructed to prove the stability of the proposed ***,numerical simulations show that compared with the linear control method,the proposed method can stabilize the attitude of the hypersonic vehicle more quickly after the inlet unstart,which provides favorable conditions for inlet restart,thus verifying the effectiveness of the augmentation method proposed in the paper.

关键词： air-breathing hypersonic vehicle(AHV) inlet unstart model reference adaptive control augmentation(MRAC) radial basis function(RBF)neural network

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Stratified sampling for data mining on the deep web

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Frontiers of Computer Science 2012年第2期6卷 179-196页

作者： TantanLIU fan、wang GaganAGRAWAL DepartmentofComputerScienceandEngineering TheOhioStateUniversityColumbusOH43210USA

In recent years, the deep web has become ex- tremely popular. Like any other data source, data mining on the deep web can produce important insights or summaries of results. However, data mining on the deep web is chal- lenging because the databases cannot be accessed directly, and therefore, data mining must be performed by sampling the datasets. The samples, in turn, can only be obtained by querying deep web databases with specific inputs. In this pa- per, we target two related data mining problems, association mining and differential rule mining. These are proposed to ex- tract high-level summaries of the differences in data provided by different deep web data sources in the same domain. We develop stratified sampling methods to perform these min- ing tasks on a deep web source. Our contributions include a novel greedy stratification approach, which recursively pro- cesses the query space of a deep web data source, and con- siders both the estimation error and the sampling costs. We have also developed an optimized sample allocation method that integrates estimation error and sampling costs. Our ex- perimental results show that our algorithms effectively and consistently reduce sampling costs, compared with a strat- ified sampling method that only considers estimation error. In addition, compared with simple random sampling, our al- gorithm has higher sampling accuracy and lower sampling costs.

关键词： deep web associate rule mining stratified sam-piing

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Vascular protection by high-density lipoprotein-associated sphingosine-1- phosphate

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Journal of Geriatric Cardiology 2017年第11期14卷 696-702页

作者： Xi wang fan wang Department of Geriatric Cardiology Chinese PLA General Hospital Beijing 100853 China

Epidemiological studies and animal experiments have consistently demonstrated cardiovascular protection by high-density lipoprotein （HDL）. Findings from a growing number of studies further indicate that sphingosine-l-phosphate （S1P） mediates many of the beneficial effects of HDL on the cardiovascular system, including vasodilatation, angiogenesis, maintenance of endothelial barrier function, and protec- tion against atherosclerosis and ischemiaJreperfusion injury. In this review, we summarize the most recent literature investigating the effects of HDL-S 1 P on cardiovascular health and highlight potential opportunities for clinical translation of these findings.

关键词： ApoM HDL-associated S1P Vascular function

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自我效能感对医学生自我污名的影响:专业心理求助态度的中介效应

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卫生职业教育 2025年第2期43卷 139-143页

作者：王帆杨夏丽宁夏医科大学护理学院宁夏银川750004

目的探讨专业心理求助态度在医学生寻求专业心理帮助的自我污名及自我效能感之间的中介效应。方法采用便利抽样法,于2023年1—11月选取某医学院校的1445名大学生,使用专业心理求助态度量表(ATSPPH)、一般自我效能感量表(GSES)、寻求专... 详细信息

目的探讨专业心理求助态度在医学生寻求专业心理帮助的自我污名及自我效能感之间的中介效应。方法采用便利抽样法,于2023年1—11月选取某医学院校的1445名大学生,使用专业心理求助态度量表(ATSPPH)、一般自我效能感量表(GSES)、寻求专业心理帮助的自我污名量表(SSOSH)进行问卷调查。结果ATSPPH总分为(68.77±6.13)分、GSES总分(26.63±8.31)分、SSOSH总分(20.19±9.53)分。ATSPPH与SSOSH呈负相关(r=-0.525,P<0.01)、与GSES呈正相关(r=0.189,P<0.01),GSES和SSOSH呈负相关(r=-0.412,P<0.01)。中介模型显示,ATSPPH在GSES与SSOSH中起部分中介作用,总效应为-0.412,直接效应为-0.293,间接效应为-0.118,中介效应占总效应的28.64%。结论医学生的GSES处于中等偏低水平,SSOSH、ATSPPH处于偏低水平。ATSPPH、GSES均可直接影响医学生的SSOSH水平,GSES也可通过ATSPPH间接影响医学生的SSOSH。医学生应积极采取策略对抗污名,增强自我效能感,提高求助态度水平,从而降低污名水平。

关键词：专业心理求助态度自我污名自我效能感医学生

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Effects of Ce on catalytic combustion of methane over Pd-Pt/Al_2O_3 catalyst

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Journal of Environmental Sciences 2012年第3期24卷 507-511页

作者： Xing fan fan wang Tianle Zhu Hong He School of Chemistry and Environment Beihang UniversityBeijing 100191China College of Environmental and Energy Engineering Beijing University of TechnologyBeifing 100124China

Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.

关键词： catalytic combustion methane Pd-Pt/Ce/Al2O3 catalyst stability metal dispersion

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Nonlinear stability of sensor elastic element--corrugated shallow spherical shell in coupled multi-field

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 877-888页

作者： Yongan ZHU fan wang Renhuai LIU Institute of Applied Mechanics Jinan University Guangzhou 510632 China Key Laboratory of Disaster Forecast and Control in Engineering of Ministry of Education Jinan University Guangzhou 510632 China

Nonlinear stability of sensor elastic element- corrugated shallow spherical shell in coupled multi-field is studied. With the equivalent orthotropic parameter obtairled by the author, the corrugated shallow spherical shell is considered as an orthotropic shallow spherical shell, and geometrical nonlinearity and transverse shear deformation are taken into account. Nonlinear governing equations are obtained. The critical load is obtained using a modified iteration method. The effect of temperature variation and shear rigidity variation on stability is analyzed.

关键词： modified iteration method corrugated shallow spherical shell multi-field,stability critical load temperature variation

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Thermohaline intrusions in the thermocline of the western tropical Pacific Ocean

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Acta Oceanologica Sinica 2013年第7期32卷 47-56页

作者： LI Yuanlong wang fan Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences Graduate University of Chinese Academy of Science

The existing high-resolution hydrographic data in the western tropical Pacilit; Ocean are used to explore the spatial distribution and primary characteristics of thermohaline intrusions in the thermocline. Statistics show that the vertical scales of intrusions are 20-40 m in the upper thermocline （22.0-26.0δ0） and 40-80 m in the lower thermocline （26.0-27.2δ0）. In the upper thermocline, the most intensive intrusions exist at the equatorial front （EF） where north/sonth Pacilic water masses converge, anti Ihe westward spreading of the north Pacilic tropical waler （NPTW） in the Philippines Sea also produces patches of intrusions surrounding its high-salinity tongue. In the lower thermocline, intrusions are also strong at the tropical front （TF） which is the boundary between the north Pacilic subtropical/tropical waters. At the bottom of the thermocline （at about 27.0δ0）, intrusions mainly exist near the western boundary, which are produced by intermediate water convergence through the advection of subthermocline western boundary Ilows. Most strikingly a ＂C＂-shape distribution of intrusions at around 26.4δ0 is revealed, covering the vicinity of the EF the TE and the Mindanao Current （MC）, i.e., tile western boundary pathway ol the norlh Pacilic subtrnpical cell （STC）. Synoptic section analysis reveals that intrusions are more prominent on the warm/sally flank ot the fronts, implying more cross-front tongues of cold/fresh water. Among the intrusions, those at the EF are of best lateral coherence which implies a unique driving mechanism involving near-inertial velocity perturbations near the equator.

关键词： thermohaline intrusions thermocline water mass western tropical Pacilic

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L_(2,1)-norm robust regularized extreme learning machine for regression using CCCP method

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The Journal of China Universities of Posts and Telecommunications 2023年第2期30卷 61-72页

作者： Wu Qing wang fan fan Jiulun Hou Jing School of Automation Xi'an University of Posts and TelecommunicationsXi'an 710121China School of Telecommunication and Information Engineering&School of Artificial Intelligence Xi'an University of Posts and TelecommunicationsXi'an 710121China School of Humanities and Foreign Languages Xi'an University of Posts and TelecommunicationsXi'an 710121China

As a way of training a single hidden layer feedforward network(SLFN),extreme learning machine(ELM)is rapidly becoming popular due to its ***,ELM tends to overfitting,which makes the model sensitive to noise and *** solve this problem,L_(2,1)-norm is introduced to ELM and an L_(2,1)-norm robust regularized ELM(L_(2,1)-RRELM)was proposed.L_(2,1)-RRELM gives constant penalties to outliers to reduce their adverse effects by replacing least square loss function with a non-convex loss *** light of the non-convex feature of L_(2,1)-RRELM,the concave-convex procedure(CCCP)is applied to solve its *** convergence of L_(2,1)-RRELM is also given to show its *** order to further verify the effectiveness of L_(2,1)-RRELM,it is compared with the three popular extreme learning algorithms based on the artificial dataset and University of California Irvine(UCI)*** each algorithm in different noise environments is tested with two evaluation criterions root mean square error(RMSE)and *** results of the simulation indicate that L_(2,1)-RRELM has smaller RMSE and greater fitness under different noise *** analysis shows that L_(2,1)-RRELM has better generalization performance,stronger robustness,and higher anti-noise ability and fitness.

关键词： extreme learning machine(ELM) non-convex loss L_(2,1)-norm concave-convex procedure(CCCP)

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