检索结果-南通市图书馆

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

引用

Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-qiang Xu Ying-Tong Di Man-cheng Tang Ding-Kang.chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han guo Zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe g, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe g metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词：

来源：

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development features and original altitude of a karst planation surface: Preliminary review

引用

Chinese Science Bulletin 2001年第S1期46卷 33-38页

作者： LI Dewen gui Zhijiu ZHANg qiang MA Baoqi Department of geography Nanjing UniversityNanjing 210093China Department of geography Peking UniversityBeijing 100871China Institute of Crystal Dynamics CSBBeijing 100085China

Traditional theories of geographical cycle and pediplain cannot describe correctly the development of planation surfaces in karst regions. Authors, therefore, put forward conception of karst planation and karst planation surface, suggesting that karst planation is another type of planation process characterized by chemical erosion and transformation. To identify the distinction between evolution features of normal landforms and those of karst landforms developed in the South China, authors suggest karst planation surfaces under similar environmental conditions may reach a lower altitude and gradient ratio, in contrast with normal landform areas. This may be applied to researching on Tibetan Plateau uplift.

关键词： karst planation surface peneplain pediplain Tibet Plateau.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development of a static test apparatus for evaluating the performance of three PM2.5 separators commonly used in China

引用

Journal of Environmental Sciences 2020年第1期32卷 238-249页

作者： Peng Du Jianguo Liu Huaqiao gui Jiaoshi Zhang Tongzhu Yu Jie Wang Yin cheng Yihuai Lu Yawei Yao qiang Fu ChihChieh chen Key Laboratory of Environmental Optics and Technology AnhuiInstitute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy cf SciencesXiamen 361021China China National Environment Monitoring Centre Beijing 100012China Institute of Occupational Medicine and Industrial Hygiene "National"Taituan UniversityChinese TaipeiTaiiuan

PM2.5 separator directly affects the accuracy of PM2.5 *** specification testing and evaluation for PM2.5 separator is particularly important,especially under China’s wide variation of terrain and *** this study,first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM2.5 separators.A uniform mixing chamber was developed to make particles mix *** aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%,and the particle size distribution obeyed logarithmic normal distribution with an R2 of *** flow rate deviation between the measurement and the set point flow rate agreed to within±1.0%in the range of-40 to 50℃.Secondly,the separation,flow and loading characteristics of three cyclone separators(VSCC-A,SCC-A and SCC112)were evaluated using this *** results showed that the 50%cutoff sizes(D50)of the three cyclones were 2.48,2.47 and 2.44μm when worked at the manufacturer’s recommended flow rates,*** geometric standard deviation(gSD)of the capture efficiency of VSCCA was 1.23,showed a slightly sharper than SCC-A(gSD=1.27),while the SCC112 did not meet the relevant indicator(gSD=1.2±0.1)with a gSD=*** flow rate and loading test had a great effect on D50,while the gSD remained almost the same as *** addition,the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test.

关键词： PM2.5 separator Performance assessment Separation characteristics Flow characteristics Loading test

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

High dispersion Pt nanoparticles using mesoporous carbon support for enhancing conversion efficiency of dye-sensitized solar cells

引用

Chinese Chemical Letters 2010年第12期21卷 1513-1516页

作者： gui qiang Wang Jun Feng gu Shu Ping Zhuo School of Chemical Engineering Shandong University of Technology Zibo 255049 China

Mesoporous carbon（MC） with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar ***/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet *** was found that Pt nanoparticles were uniform in size and highly dispersed on MC *** average size of Pt nanoparticles is about 3.4 ***/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide *** overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.

关键词： Mesoporous carbon Pt nanoparticles Counter electrode Dye-sensitized solar cells

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect and mechanism of encapsulation on aging characteristics of quantum-dot light-emitting diodes

引用

Nano Research 2021年第1期14卷 320-327页

作者： Zinan chen qiang Su Zhiyuan Qin Shuming.chen guangdong University Key Lab for Advanced Quantum Dot Displays and Lighting Shenzhen Key Lab for Advanced Quantum Dot Displays and Lightingand Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen 518055China Key Laboratory of Energy Conversion and Storage Technologies(Southern University of Science and Technology) Ministry of EducationShenzhen 518055China

The aging characteristics,e.g.,the evolution of efficiency and luminance of quantum-dot light-emitting diodes(QLEDs)are greatly affected by the *** encapsulated with ultraviolet curable resin,the efficiency is increased over time,a known phenomenon termed as positive aging which remains one of the unsolved *** developing a physical model and an analytical model,we identify that the efficiency improvement is mainly attributed to the suppression of hole leakage current that is resulted from the passivation of ZnMgO *** further encapsulated with desiccant,the positive aging effect *** take the advantage of positive aging,the desiccant is incorporated after the positive aging process is *** the new encapsulation method,the QLED exhibits a high external quantum efficiency of 20.19%and a half lifetime of 1,267 h at an initial luminance of 2,800 cd·m^(-2),which are improved by 1.4 and 6.0 folds,respectively,making it one of the best performing *** work provides an in-depth and systematic understanding of the mechanism of positive aging and offers a practical encapsulation way for realizing efficient and stable QLEDs.

关键词： quantum-dot light-emitting diodes positive aging encapsulation ZnO defects

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Thermodynamics of Cascaded Waste Heat Utilization from Flue gas and Circulating Cooling Water

引用

Journal of Thermal Science 2023年第6期32卷 2166-2178页

作者： LI Yuanyuan chen Xin JIANg Shan LU gui State Key Laboratory of New Energy Power Systems North China Electric Power UniversityBeijing102206China Department of Water Resources China Institute of Water Resources and Hydropower ResearchBeijing100038China School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing102206China

A detailed thermal power plant model was developed to evaluate power plant waste heat usage in terms of the operating parameters,energy consumption,water consumption,and pollutant *** model was used to analyze the bypass flue gas energy cascade utilization design which provides excellent energy savings and emission *** paper then presents a design to use the low-temperature waste heat and to extract water from the flue *** low-grade heat can be recovered from a coal-fired unit using absorption heat pumps to increase the air *** method significantly reduces the turbine steam extraction in the low pressure stages which increases the turbine power and reduces the coal *** design has a small heat transfer temperature difference between the air preheater and the air warmer,resulting in a smaller exergy *** power output of the present design was 1024.28 MW with a coal consumption savings of 3.69 g·(kWh)^(−1).In addition,the present design extracts moisture out of the flue gas to produce 46.48 t·h^(−1)of *** main goal of this work is to provide a theoretical analysis for studying complex thermal power plant systems and various energy conservation and CO_(2)reduction options for conventional power plants.

关键词： integrated thermal power plant model low-grade waste heat energy cascade utilization exergy losses absorption heat pumps

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quasi-MOF-immobilized metal nanoparticles for synergistic catalysis

引用

Science China Chemistry 2020年第11期63卷 1601-1607页

作者： Liyu chen Nobuko Tsumori qiang Xu AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory(ChEM-OIL) National Institute of Advanced Industrial Science and Technology(AIST)YoshidaSakyo-kuKyoto 606-8501Japan Toyama National College of Technology 13 Hongo-machiToyama 939-8630Japan School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

Through partial deligandation of metal-organic frameworks(MOFs),quasi-MOFs with a transition structure between MOFs and metal compounds(such as metal oxides,nitrides,sulfides,and phosphides)can be ***-MOFs can not only retain the porous structure of MOFs to a certain extent,but also expose the inorganic nodes to the guest species(e.g.,metal nanoparticles)to show enhanced metal-support interaction for synergistic *** concept was first demonstrated by our group through calcining Au/MIL-101 at different temperatures under Ar flow to adjust the interface between Au nanoparticles and the inorganic Cr–O *** obtained Au/quasi-MIL-101 showed superior enhanced catalytic activity in the oxidation of carbon *** study has inspired further research interest to fabricate other quasi-MOFs through controlled deligandation of mono-and bimetallic MOFs and their composites for the design of efficient catalysts.

关键词： MOFs metal nanoparticles metal-support interaction quasi-MOFs synergistic catalysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Extracting optimal actionable plans from additive tree models

引用

Frontiers of Computer Science 2017年第1期11卷 160-173页

作者： qiang LU Zhicheng CUI Yixin chen Xiaoping.chen College of Information Engineering Yangzhou University Yangzhou 225127 China Department of Computer Science and Engineering Washington University in St. Louis St. Louis MO 63130 USA School of Computer Science and Technology University of Science and Technology of China Hefei 230026 China

Although amazing progress has been made in ma- chine learning to achieve high generalization accuracy and ef- ficiency, there is still very limited work on deriving meaning- ful decision-making actions from the resulting models. How- ever, in many applications such as advertisement, recommen- dation systems, social networks, customer relationship man- agement, and clinical prediction, the users need not only ac- curate prediction, but also suggestions on actions to achieve a desirable goal （e.g., high ads hit rates） or avert an unde- sirable predicted result （e.g., clinical deterioration）. Existing works for extracting such actionability are few and limited to simple models such as a decision tree. The dilemma is that those models with high accuracy are often more complex and harder to extract actionability from. In this paper, we propose an effective method to extract ac- tionable knowledge from additive tree models （ATMs）, one of the most widely used and best off-the-shelf classifiers. We rigorously formulate the optimal actionable planning （OAP） problem for a given ATM, which is to extract an action- able plan for a given input so that it can achieve a desirable output while maximizing the net profit. Based on a state space graph formulation, we first propose an optimal heuris- tic search method which intends to find an optimal solution. Then, we also present a sub-optimal heuristic search with an admissible and consistent heuristic function which can re- markably improve the efficiency of the algorithm. Our exper- imental results demonstrate the effectiveness and efficiency of the proposed algorithms on several real datasets in the application domain of personal credit and banking.

关键词： actionable knowledge extraction machine learning additive tree models state space search

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Measures of imaginarity and quantum state order

引用

Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 26-35页

作者： Qiang.chen Ting gao Fengli Yan School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024China College of Physics Hebei Key Laboratory of Photophysics Research and ApplicationHebei Normal UniversityShijiazhuang 050024China

Complex numbers are widely used in classical and quantum ***,they play an important role in describing quantum systems and their dynamical ***,we propose several measures of the imaginarity of quantum states based on l1 norm and convex functions in the framework of resource ***,we investigate the quantum state order after a quantum system passes through a real *** proof shows that these proposed measures possess all the desirable properties for a measure of *** connection between the measure of imaginarity based on the l1 norm and the measure of imaginarity based on relative entropy is ***,we demonstrate that the l1 norm-based and the relative entropy-based measures of imaginarity are of the same order for qubit quantum *** we discuss the influences of the bit flip channel,phase damping channel,and amplitude flip channel on single qubit state order.

关键词： measure imaginarity quantum state order

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis of a Novel Blue- light- emitting Polymer Material Bearing Coumarin Pendants

引用

Chinese Chemical Letters 2002年第7期13卷 674-677页

作者： Zhi Yun LU Tong Suo YUAN Yan Lai chen Xiao qiang WEI Wei guo ZHU Ming gui XIE Department of Chemistry Sichuan UniversityChengdu 610064

A novel blue luminescent polymer bearing coumarin pendants was prepared. Its luminescent properties were determined indicating that it had strong blue fluorescent properties and good film formation ability. This nov... 详细信息

关键词： Synthesis coumarin fluorescence polymer blue organic electroluminescent material.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：