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Cyano migration-mediated radical-polar crossover cyclopropanation

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Science China Chemistry 2025年第01期 241-248页

作者： Ziqiang Wang Yasu Chen Jie Li Chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials ScienceSoochow University Frontiers Science Center for Transformative Molecules Zhangjiang Institute for Advanced Study and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Shanghai Jiao Tong University

We report a novel cyano migration-mediated radical-polar crossover process, whereby both the sulfonylcyanation of aliphatic alkenes and the formation of cyclopropanes are concurrently achieved. This transformation yields a diverse array of multisubstituted cyclopropanes under mild photocatalytic conditions. Mechanistic studies elucidate that the reaction proceeds via intramolecular nucleophilic substitution, leading to the formation of the cyclopropane derivatives.

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Iron-Catalyzed Amide Bond Formation from Carboxylic Acids and Isocyanates

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Chinese Journal of Chemistry 2023年第23期41卷 3268-3274页

作者： Lingjian Zi Jing Zhang The institute for advanced studies Wuhan UniversityWuhanHubei430072 China

We describe an iron-catalyzed amide bond formation from readily available carboxylic acids and *** method utilizes an abundant and biocompatible iron catalyst and easily accessible starting materials,generates CO_(2) as the only byproduct,and features broad substrate scopes with good functional group ***,it provides a cost-effective and practical protocol to access a diverse variety of amides.

关键词： Iroen Carboxylic acids Amides C—N bond formation Rearrangement

Modification of mechanical properties by TiO_2 nano-particle for biodegradable materials made from palm oil sludge and activated sludge cake

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中国有色金属学会会刊：英文版 2012年第S3期22卷 697-701页

作者： Panithi YUTHAVISUTHI Lerpong JARUPAN Chiravoot PECHYEN Department of Packaging and Materials Technology Faculty of Agro-IndustryKasetsart University Center for advanced studies in Agriculture and Food (CASAF) KU Institute for Advanced Studies Kasetsart University

Titanium dioxide (TiO2) nano-particle is widely used in composite materials to its improved mechanical ***2 nano-particle was used in the composite material that consists of palm oil sludge from the palm oil production and activated sludge cake from a papermaking ***2 was synthesized by a hydrolysis of titanium *** parameter was investigated by the mole ratio of reactant to different solvents (isopropanol and isobutanol).The solution was prepared by adjusting pH to acid solution,resulting in different sizes and distributions of precipitate which was heated at different *** obtained samples were then morphologically and structurally characterized using X-ray diffraction (XRD) and particle size distribution (PSD).The experimental results show that the TiO2 sample from isopropanol solvent with heated temperature of 600 °C exhibits the best ***,different mass fractions of TiO2 (0,0.5%,1.0%,2.0%,4.0% and 8.0%) were used for specimens that were made from palm oil sludge mixed with activated sludge *** samples were later characterized by 3-point bending test and compression *** results indicate that the adding 0.5% and 1.0% TiO2 particles to the composite material outperforms the other fractions in terms of enhancing mechanical ***,mechanical properties tends to decrease when adding 2.0% TiO2.

关键词： titanium dioxide palm oil sludge active sludge cake composite mechanical properties

Climate change and its consequences for water and wastewater management

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Frontiers of Environmental Science & Engineering 2009年第1期3卷 2-11页

作者： Peter A.WILDERER institute of advanced studies on Sustainability Amalienstr7580799 MunichGermany

Life,in combination with solar radiation and abiotic processes,is most probably the reason why liquid water has existed on Earth for over billions of years,and the global mean temperature has remained in a lifeenabling *** to limit or even reverse global warming must be derived from the knowledge of the Earth’s complex life-support *** this context,the balance between liquid and gaseous water plays a crucial role,and water management becomes an important field of innovation and action,globally,on the scale of watersheds but also on the very local *** use,reuse,and temporary storage of water in urban settings must be considered to limit over-extraction of water from natural resources,and to maintain the life supporting function of *** the same time,public health requirements,cost efficiency,and reliability demands are to be met.

关键词： ecosystem management tools self-regulation urbanization water-climate relationship water reuse

Synergistic Pd/Cu-catalyzed regio-and stereoselective cascade Heck cyclization/borylation/cross-coupling

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Chinese Chemical Letters 2023年第12期34卷 166-171页

作者： Yifan Wang Yuanyuan Ping Wangqing Kong The institute for advanced studies(IAS) Wuhan University.Wuhan 430072China

A cooperative Pd/Cu-catalyzed three-component cross-coupling reaction of alkynes,B_(2)Pin_(2) and alkene-tethered aryl halides is *** reaction proceeds under mild conditions and shows broad sub-strate scope,providing a variety of heterocycles containing tetrasubstituted alkenylboronate moieties in synthetically useful yields with excellent chemoselectivity and *** transformation fea-tures the catalytic generation ofβ-borylalkenylcopper intermediates and their use in Pd-catalyzed Heck cyclization/*** enantioselective cascade cyclization/cross-coupling process has also been developed for the synthesis of enantiomerically enriched oxindole bearing a tetrasubstituted alkenyl-boronate moiety.

关键词： Palladium/copper catalysis Heck cyclization Alkene difunctionalization Cross-coupling Borylation

Synthesis of gem-Difluoroalkenes via Ni-Catalyzed Three-Component Defluorinative Reductive Cross-Coupling of Organohalides,Alkenes and Trifluoromethyl Alkenes

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Chinese Journal of Chemistry 2022年第18期40卷 2212-2218页

作者： Teng Ma Xiao Li Yuanyuan Ping Wangqing Kong The institute for advanced studies(IAS) Wuhan UniversityWuhanHubei430072 China

gem-Difluoroalkenes are considered ideal isosteres for metabolically susceptible carbonyl groups in modern drug discovery and medicinal *** addition,gem-difluoroalkenes are used as versatile precursors for the synthesis of difluoroalkylated compounds and ***,a great deal of effort has been devoted to developing efficient methods for their *** catalytic defluorinative functionalization of trifluoromethyl alkenes represents a useful strategy for the preparation of chiral ***,most of these catalytic processes are still essentially limited to two-component defluorinative cross-couplings to form single C—C *** to the challenge of controlling chemoselectivity in the carbon-carbon bond forming events,three-component defluorinative cross-coupling involving multiple C—C bond formations has rarely been *** report a nickel-catalyzed three-component defluorinative reductive cross-coupling of organohalides,alkenes and trifluoromethyl alkenes.A variety of electron-rich and electron-deficient alkenes,as well as aryl and alkyl halides can efficiently participate in the formation of three-component cross-coupling *** reaction proceeds under mild conditions and exhibits excellent functional group compatibility without requiring a pendant chelating group,providing a variety of functionalized gem-difluoroalkenes in good yields with excellent chemoselectivity.

关键词： Nickel C-C coupling Multicomponent reactions gem-Difluoroalkenes Defluorinative coupling Reductive cross-coupling

DTA-HOC:Online HTTPS Traffic Service Identification Using DNS in Large-Scale Networks

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Tsinghua Science and Technology 2020年第2期25卷 239-254页

作者： Xuemei Zeng Xingshu Chen Guolin Shao Tao He Lina Wang cybersecurity Research institute Sichuan UniversityChengdu 610065China College of cybersecurity Sichuan UniversityChengdu 610065China College of Computer Science Sichuan UniversityChengdu 610065China

An increasing number of websites are making use of HTTPS encryption to enhance security and privacy for their ***,HTTPS encryption makes it very difficult to identify the service over HTTPS flows,which poses challenges to network security *** this paper we present DTA-HOC,a novel DNS-based two-level association HTTPS traffic online service identification method for large-scale networks,which correlates HTTPS flows with DNS flows using big data stream processing and association technologies to label the service in an HTTPS flow with a specific associated domain ***-HOC has been specifically designed to address three practical challenges in the service identification process:domain name ambiguity,domain name query invisibility,and data association time window size *** experiments on datasets collected from a 10-Gbps campus network are conducted alongside offline and online *** show that DTA-HOC can achieve an average online association rate on HTTPS traffic of 83%and a generic accuracy of 86.16%.Its processing time for one minute of data is less than 20 *** results indicate that DTA-HOC is an efficient method for online identification of services in HTTPS flows for large-scale ***,our proposed method can contribute to the identification of other applications which make a Domain Name System(DNS)communication before establishing a connection.

关键词： HTTPS Domain Name System(DNS) service identification big data flow association

A New Revocable and Re-Delegable Proxy Signature and Its Application

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Journal of Computer Science & Technology 2018年第2期33卷 380-399页

作者： Shengmin Xu Guomin Yang Yi Mu institute of cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Wollongong 2500 Australia

With the popularity of cloud computing and mobile Apps, on-demand services such as on-line music or audio streaming and vehicle booking are widely available nowadays. In order to allow efficient delivery and management of the services, for large-scale on-demand systems, there is usually a hierarchy where the service provider can delegate its service to a top-tier （e.g., countrywide） proxy who can then further delegate the service to lower level （e.g., region-wide） proxies. Secure （re-）delegation and revocation are among the most crucial factors for such systems. In this paper, we investigate the practical solutions for achieving re-delegation and revocation utilizing proxy signature. Although proxy signature has been extensively studied in the literature, no previous solution can achieve both properties. To fill the gap, we introduce the notion of revocable and re-delegable proxy signature that supports efficient revocation and allows a proxy signer to re-delegate its signing right to other proxy signers without the interaction with the original signer. We define the formal security models for this new primitive and present an efficient scheme that can achieve all the security properties. We also present a secure on-line revocable and re-delegate vehicle ordering system （RRVOS） as one of the applications of our proposed scheme.

关键词： revocation (re)delegation proxy signature

Voltammetric determination of stability constants of lead complexes with diallyl disulfide, dimethyl disulfide, and diallyl sulfide

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Chinese Chemical Letters 2016年第1期27卷 71-76页

作者： Mohammad Ali Kamyabi Fatemeh Soleymani-Bonoti Saeed Zakavi Department of Chemistry University of Zanjan Department of Chemistry Institute for Advanced Studies in Basic Sciences

The complexation of Pb^（2＋）by diallyl disulfide（DADS）, dimethyl disulfide（DMDS） and diallyl sulfide（DAS）has been studied by differential pulse voltammetry. Stability constants,（log b）, of the 1：1（PbL） and 1：2（PbL_2） complexes, where L = ligand, were found to be in the range of ca. 3.8-4.2 and 9.4-10.2,respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of the Pb2＋/Pb half-wave potential to a higher one upon the addition of the sulfur containing ligands（L）. The formation of 1：1 and 1：2 complexes, i.e., PbL^（2＋）and PbL_2^（2＋）was observed in the case of the three ligands. The consecutive formation constants of labile lead complexes with DADS, DMDS, and DAS were determined at 298 K by the method of De Ford and Hume. Apparently due to the large size of the lead ion,steric hindrance caused by the greater steric bulk of DADS compared to that of DMDS have little or no effects on the formation constants, so that very similar values were obtained in the case of the two ligands. Also, the possible participation of C=C double bonds in coordination with the metal center in the case of DADS appears to compensate for the steric effects caused by the larger size of this ligand. In agreement with the Jorgensen principle of symbiosis, the second formation constants were found to be approximately six orders of magnitude greater than the first ones.

关键词： Garlic oil Organic sulfur compounds Pb^(2+)-DADS,DMDS,and DAS complexes Stability constant