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Ruthenium-Catalysed Asymmetric Intramolecular Isomerization/Esterification Reaction: Direct Synthesis of Chiral Dihydrocoumarins

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Chinese Journal of Chemistry 2024年第16期42卷 1828-1832页

作者： Lingzi Zhao Xuchao Wang Qing Qiang Xingwei Zhao feipeng liu Shenci Lu Zi-Qiang Rong Frontiers Science Center for Flexible Electronics(FSCFE) Shaanxi Institute of Flexible Electronics(SiFE)&Shaanxi Institute of Biomedical Materials and Engineering(SIBME)Northwestern Polytechnical University(NPU)127 West Youyi RoadXianShaanxi 710072China Honors College Northwestern Polytechnical University(NPU)127 West Youyi RoadXi'anShaanxi 710072China

An asymmetric isomerization/intramolecular coupling reaction of allylic alcohols to synthesize chiral dihydrocoumarins was successfully accomplished through ruthenium *** method demonstrates a wide substrate applicability,excellent tolerance for various functional groups,and good enantioselectivities(up to 90%ee).It provides a convenient pathway to produce a diverse range ofstructurallydistinct chiral dihydrocoumarins ingoodefficiency.

关键词： Ruthenium catalysis Asymmetric isomerization Tandem reaction Chiral dihydrocoumarins Enantioselectivity

Transition metal-catalyzed conversion of aldehydes to ketones

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Chinese Chemical Letters 2022年第3期33卷 1207-1226页

作者： Zijuan Yan Pan-Lin Shao Qing Qiang feipeng liu Xuchao Wang Yongjie Li Zi-Qiang Rong Frontiers Science Center for Flexible Electronics(FSCFE) Shaanxi Institute of Flexible Electronics(SIFE)&Shaanxi Institute of Biomedical Materials and Engineering(SIBME)Northwestern Polytechnical University(NPU)Xi'an 710072China College of Innovation and Entrepreneurship Southern University of Science and TechnologyShenzhen 518055China

Ketones are one of the most important classes of organic compounds, and widely present in various pharmacological compounds, biologically active molecules and functional materials. Over the past few decades, transition metal-catalyzed conversion of aldehydes has been found to be a powerful *** the continuous development in recent years, it has become an efficient and uncomplicated strategy for constructing ketones. There are four major mechanisms for transition metal-catalyzed ketone synthesis from aldehyde:(1) carbonyl-Heck reaction, that is 1,2-insertion of organometal species to aldehydic C=O double bond,(2) direct insertion of transition metal catalysts to aldehydic C-H bond,(3) aldehyde as acyl radical,(4) aldehyde as carbon radical acceptor. This article summarizes related reports on the transformations of aldehydes to generate corresponding ketones under different reaction conditions.

关键词： Homogeneous catalysis Transition metal catalysis Direct conversion Ketone synthesis C-H bond functionalization

A Machine-Learning Approach for the Prediction of Fly-Ash Concrete Strength

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Fluid Dynamics & Materials Processing 2023年第12期19卷 3007-3019页

作者： Shanqing Shao Aimin Gong Ran Wang Xiaoshuang Chen Jing Xu Fulai Wang feipeng liu College of Water Conservancy Yunnan Agricultural UniversityKunming650201China Institute of International Rivers and Eco-Security Yunnan UniversityKunming650500China Southwest Survey and Planning Institute of National Forestry and Grassland Administration Kunming650031China

The composite exciter and the CaO to Na_(2)SO_(4) dosing ratios are known to have a strong impact on the mechanical strength offly-ash *** the present study a hybrid approach relying on experiments and a machine-learn-ing technique has been used to tackle this *** tests have shown that the optimal admixture of CaO and Na_(2)SO_(4) alone is 8%.The best 3D mechanical strength offly-ash concrete is achieved at 8%of the compound activator;If the 28-day mechanical strength is considered,then,the best performances are obtained at 4%of the compound ***,the 3D mechanical strength offly-ash concrete is better when the dosing ratio of CaO to Na_(2)SO_(4) in the compound activator is 1:1;the maximum strength offly-ash concrete at 28-day can be achieved for a 1:1 ratio of CaO to Na_(2)SO_(4) by considering a 4%compound *** this case,the compressive andflexural strengths are 260 MPa and 53.6 MPa,respectively;the mechanical strength offly-ash concrete at 28-day can be improved by a 4:1 ratio of CaO to Na_(2)SO_(4) by considering 8%and 12%compound *** is shown that the predictions based on the aforementioned machine-learning approach are accurate and reliable.

关键词： Fly ash compound activator machine-learning approach

Microscopic Analysis of Cementitious Sand and Gravel Damming Materia

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Fluid Dynamics & Materials Processing 2024年第4期20卷 749-769页

作者： Ran Wang Aimin Gong Shanqing Shao Baoli Qu Jing Xu Fulai Wang feipeng liu College of Water Conservancy Yunnan Agricultural UniversityKunming650201China Tianqi Engineering Consulting Co. Ltd.Kunming650000China Institute of International Rivers and Ecological Security Yunnan UniversityKunming650500China

The mechanical properties of cementitious sand and gravel damming material have been experimentally determined by means of microscopic SEM(Scanning Electron Microscopy)image *** results show that the combination of fly ash and water can fill the voids in cemented sand and gravel test blocks because of the presence of hydrated calcium silicate and other substances;thereby,the compactness and mechanical properties of these materials can be greatly *** every 10 kg/m^(3) increase in the amount of cementitious material,the density increases by about 2%,and the water content decreases by 0.2%.The amount of cementitious material used in the sand and gravel in these tests was 80-110 kg/m^(3),the water-binder ratio was ***,the splitting tensile strength was 1/10 of the compressive strength,and the maximum strength was 7.42 MPa at 90 *** optimal mix ratio has been found to be 50 kg of cement,60 kg of fly ash and 120 kg of water(C50F60W120).The related dry density was 2.6 g/cm^(3),the water content was 6%,and the water-binder ratio was 1.09.

关键词： Cementitious sand gravel material scanning electron microscopy optimal mix ratio maximum strength

应对高杂散电感的三电平ANPC拓扑改进调制策略

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高电压技术 2021年第2期47卷 637-644页

作者：段立扬刘飞鹏许烈郭有贵湘潭大学信息工程学院湘潭411105 清华大学先进电能变换与电气化交通研究中心北京100084

针对高频大功率三电平有源钳位型(active neutral point clamped,ANPC)电路运行时的四象限换流回路进行了分析,考虑高杂散电感下不同换流回路对ANPC运行的影响,分别得出小换流回路与大换流回路的电压应力情况。对比了ANPC三电平正弦脉... 详细信息

针对高频大功率三电平有源钳位型(active neutral point clamped,ANPC)电路运行时的四象限换流回路进行了分析,考虑高杂散电感下不同换流回路对ANPC运行的影响,分别得出小换流回路与大换流回路的电压应力情况。对比了ANPC三电平正弦脉宽调制(sinusoidal pulse width modulation,SPWM)中的两种调制策略载波层叠(phase disposition pulse width modulation,PDPWM)与载波移相(phase shift pulse width modulation,PSPWM),为尽量避免大换流回路应采用PDPWM调制策略。在高杂散电感的情况下,加入吸收电容会后产生谐振,通过对其换流回路进行详细分析,总结出谐振产生的原因,提出了改进的PDPWM的调制策略。仿真与实验结果验证了理论分析的正确性,谐振得到有效的抑制。

关键词： ANPC PSPWM PDPWM 杂散电感换流回路谐振

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毛细管气相色谱法分离2-苯基羧酸酯对映体

色谱 2016年第1期34卷 85-88页

作者：史雪岩刘飞鹏边庆花中国农业大学农学与生物技术学院北京100193 中国农业大学理学院北京100193

手性2-芳基羧酸酯是制备手性非甾体抗炎药物2-芳基羧酸的重要的中间体,为了建立可用于2-苯基羧酸酯对映体分离的手性毛细管气相色谱法(CGC),分别使用2,6-二-O-戊基-3-O-丁酰基-β-环糊精及2,6-二-O-苄基-3-O-庚酰基-β-环糊精作毛细管... 详细信息

手性2-芳基羧酸酯是制备手性非甾体抗炎药物2-芳基羧酸的重要的中间体,为了建立可用于2-苯基羧酸酯对映体分离的手性毛细管气相色谱法(CGC),分别使用2,6-二-O-戊基-3-O-丁酰基-β-环糊精及2,6-二-O-苄基-3-O-庚酰基-β-环糊精作毛细管气相色谱手性固定相,研究了其对2-苯基丁酸甲酯、2-苯基丁酸乙酯、2-苯基丁酸异丙酯、2-苯基丙酸甲酯及2-苯基丙酸环戊酯等5种2-苯基羧酸酯对映体的分离能力。结果表明,用2,6-二-O-戊基-3-O-丁酰基-β-环糊精及2,6-二-O-苄基-3-O-庚酰基-β-环糊精作手性固定相的毛细管气相色谱法可以分离2-苯基丁酸甲酯、2-苯基丙酸甲酯和2-苯基丙酸环戊酯对映体。2,6-二-O-戊基-3-O-丁酰基-β-环糊精对3种2-苯基羧酸酯对映体的分离能力超过了2,6-二-O-苄基-3-O-庚酰基-β-环糊精。

关键词：毛细管气相色谱 β-环糊精衍生物手性固定相 2-苯基羧酸酯对映体分离

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图像处理技术在车牌号识别领域中的算法改进

电视技术 2016年第12期40卷 28-33页

作者：刘飞鹏沈希忠上海应用技术大学电气与电子工程学院上海201418

针对图像处理技术在车牌号识别领域中的运用,结合目前常用识别方法(模板匹配法、神经网络法和支持向量机识别法)和主要特征提取方式(统计特征提取和结构特征提取)各自的优点,设计出一种多层分支结构的车牌号识别系统,该系统根据不同待... 详细信息

针对图像处理技术在车牌号识别领域中的运用,结合目前常用识别方法(模板匹配法、神经网络法和支持向量机识别法)和主要特征提取方式(统计特征提取和结构特征提取)各自的优点,设计出一种多层分支结构的车牌号识别系统,该系统根据不同待识别字符的特征进行分类,然后匹配上对该类特征识别较有优势的特征提取方法和字符识别算法,并提出一种对折识别算法运用其中,通过对字符的分层识别和分支识别,从而达到精确、高效识别的目的,最后通过试验测试和统计分析,证明了该方法在车牌号识别中的优越性。

关键词：车牌号识别图像处理易混字识别

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消费型无人机在复杂区域三维重建精度验证

北京测绘 2023年第2期37卷 185-189页

作者：刘飞鹏江西核工业测绘院集团有限公司江西南昌330199

针对消费型无人机在复杂区域三维(3D)重建精度难以保证问题,本文借助消费型无人机飞马D2000完成复杂地形的实景三维数据生成。首先,通过参数畸变与格网畸变结合的方式对多视影像数据进行畸变处理,消除多视影像畸变误差;然后,利用带有相... 详细信息

针对消费型无人机在复杂区域三维(3D)重建精度难以保证问题,本文借助消费型无人机飞马D2000完成复杂地形的实景三维数据生成。首先,通过参数畸变与格网畸变结合的方式对多视影像数据进行畸变处理,消除多视影像畸变误差;然后,利用带有相对姿态参数的多视影像光束法区域网平差的数学模型进行平差处理,避免平差解算参数过多导致解算参数不稳定问题;最后,通过工程实例验证本文方法可行性,为相关工程提供参考。

关键词：复杂区域影像畸变改正多视影像平差三维(3D)重建精度验证

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消费型无人机在河道精细化三维构建中的应用

测绘与空间地理信息 2024年第3期47卷 29-31,35页

作者：刘飞鹏江西核工业测绘院集团有限公司江西南昌330199

针对消费型无人机倾斜摄影测量技术获取河道大区域复杂地形多视影像存在一定局限性,导致河道实景三维模型存在空洞与缺失问题,提出消费型无人机在河道精细化三维构建中的应用方法。通过不同航拍方式获取目标区域详细的多视影像数据,结... 详细信息

针对消费型无人机倾斜摄影测量技术获取河道大区域复杂地形多视影像存在一定局限性,导致河道实景三维模型存在空洞与缺失问题,提出消费型无人机在河道精细化三维构建中的应用方法。通过不同航拍方式获取目标区域详细的多视影像数据,结合多种成熟软件进行河道区域精细化建模,有效地解决三维模型存在空洞与缺失问题,获取了高精度、精细化实景三维模型,为大区域、复杂情况的河道精细化建模提供一种思路。

关键词：消费型无人机河道精细化三维构建精度验证