检索结果-南通市图书馆

Recent Advances in Enantioselective Reactions of Terminal Unactivated Alkenes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第7期42卷 760-776页

作者： Qihang guo Xuzhong Shen zhan Lu Centerof ChemistryforFrontier Technologies Departmentof ChemistryZhejiang UniversityHangzhouZhejiang 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center HangzhouZhejiang 311215China College of Chemistry Zhengzhou UniversityZhengzhouHenan 450001China

α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural *** to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance *** review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.

关键词： Asymmetric catalysis Terminal unactivated alkenes Hydrofunctionalization Difunctionalization Metal-catalyzed

Chirality transfer induced circularly polarized luminescence of achiral dye molecules by plasmonic nanohelicoid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8408-8414页

作者： Han gao ChunLian zhan Tianqi Zhao Jianzhong Zheng College of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China School of Environmental Science and Engineering Nanjing Tech UniversityNanjing 211816China

Optical materials with circularly polarized luminescence(CPL)features have attracted a growing interest due to their crucial role in biological sensing,display,spintronics,information storage,and so ***,CPL emissions in hybrid nanoparticle systems,in particular,chirality transfer induced CPL from chiral plasmonic nanoparticles,have rarely been explored due to a lack of effective bottom-up synthesis ***,we creatively take advantage of the newly introduced chiral plasmonic nanoparticles-gold nanohelicoid(GNH)to excite the CPL of achiral Rhodamine 6G(R6G).The fabricated GNH@R6G-SiO_(2)shows obvious CPL signals with|g_(lum)|up to *** with the single GNH,the photoluminescence(PL)dissymmetry factor of the single GNH@R6G-SiO_(2)is similar,but with 25 folds higher PL intensities under different circular *** research not only offers an effective and feasible method to fabricate single-particle level CPL-active materials,but also provides guidelines on how to regulate the CPL of achiral luminophores from chiral plasmonic nanostructures,thereby enlarging the category and quantity of CPL-active materials that can be applied for photonic technologies and visualization biosensing,especially some intracellular chirality related detection.

关键词： circularly polarized luminescence gold nanohelicoids chiral plasmonic

Exchange of a nuclear corepressor between NF-kB and CREB mediates inhibition of phosphoenolpyruvate carboxykinase transcription by NF-kB

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2010年第2期123卷 221-226页

作者： YAN Jin-hua gao zhan-guo YE Jian-ping WENG Jian-ping Department of Endocrinology Yat-sen University Guangzhou JH and Weng JP) Third Affiliated Hospital Sun Guangdong 510630 China Pennington Biomedical Research Center Louisiana State University System Baton Rouge LA 70808 USA

Background NF-KB p65 was shown to inhibit transcription of phosphoenolpyruvate carboxykinase （PEPCK）, a rate-limiting enzyme in gluconeogenesis in the liver. To understand the mechanism of action of NF-KB p65, we investigated the nuclear receptor corepressor in the regulation of PEPCK transcription. Methods Rat H411E cells, human hepatoma HepG2 cells and human embryo kidney （HEK） 293 cells were used in this study. The transcriptional activity of a rat PEPCK gene promoter （-490/＋100） was analyzed in HepG2 cells, a HepG2 super suppressor IkBa （sslkBa） stable cell line, and HEK 293 cells. The effects of p65 and sslkBa on a rat PEPCK gene promoter were observed using the PEPCK luciferase reporter system. The interaction of the cAMP-response- element-binding （CREB） protein, histone deacetylase 3 （HDAC3） and silencing mediator for retinoic and thyroid hormone receptors （SMRT） with the PEPCK gene promoter were investigated using the chromatin immunoprecipitation （CHIP） assay, p65 cotransfection and RNAi-mediated gene knockdown were used to determine the corepressor involved in the inhibition of PEPCK by NF-KB p65 and the transcriptional regulation of CREB by NF-KB p65. Results NF-KB p65 inhibited PEPCK expression and the inhibition was blocked by sslkBa. The inhibitory effect of p65 was completely blocked in a HepG2 stable cell line in which sslkBa was expressed. HDAC3 or SMRT knockdown led to a significant up-regulation of PEPCK reporter activity in the presence of p65 cotransfection. In the ChIP assay the interaction of HDAC3 and SMRT with the PEPCK gene promoter was induced by p65 activation, but the CREB signal was reduced. Transcriptional activity of CREB was inhibited by NF-kB p65 cotransfection. The inhibitory effect of NF-kB p65 was blocked by HDAC3 RNAi or SMRT RNAi. Conculsions The study showed that the inhibition of PEPCK by NF-kB p65 was dependent on HDAC3 and SMRT, which form a nuclear corepressor complex for transcriptional inhibition. The transcription facto

关键词： phosphoenolpyruvate carboxykinase NF-kappa B nuclear receptor corepressor 1

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao guo Peifeng gao Xingzhe WANG Key Laboratory of Mechanics on Western Disaster and Environment of Ministry of Education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting *** respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic *** numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally ***,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake *** approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic *** then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic *** results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and *** proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

Stabilizing iridium sites via interface and reconstruction regulations for water oxidation in alkaline and acidic media

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第2期89卷 355-363,I0009页

作者： Weibin Chen Yanhui Song Lei Li Junjie guo zhan Lin Guangdong Provincial Key Laboratory of Plant Resources Biorefinery School of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina Key Laboratory of Interface Science and Engineering in AdvancedMaterials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024ShanxiChina

Exploring effective iridium(Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction(OER).Herein,we regulated the incorporation manner of Ir in Co_(3)O_(4)support to stabilize the Ir sites for effective *** anchored on the surface of Co_(3)O_(4)in the form of Ir(OH)_6 species,the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir *** doped into Co_(3)O_(4)lattice,the analyses of X-ray absorption spectroscopy,in-situ Raman,and OER measurements show that the partially replacement of Co in Co_(3)O_(4)by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface,and simultaneously master the reconstruction effect to mitigate Ir dissolution,realizing the improved OER activity and stability in alkaline and acidic *** a result,Ir_(lat)@Co_(3)O_(4)with Ir loading of 3.67 wt%requires 294±4 mV/285±3 mV and 326±2 mV to deliver 10 mA cm^(-2)in alkaline(0.1 M KOH/1.0 M KOH)and acidic(0.5 M H_(2)SO_(4))solution,respectively,with good stability.

关键词： Interface effect Reconstruction Ir dissolution Ir-O-Co Oxygen evolution reaction

Evaluation of the energy budget of thermokarst lake in permafrost regions of the Qinghai-Tibet Plateau

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第4期15卷 636-646页

作者： Ze-Yong gao Fu-Jun NIU Yi-Bo WANG Jing LUO guo-An YIN Yun-Hu SHANG zhan-Ju LIN Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of ScienceLanzhou 730000China College of Earth and Environment Science Lanzhou UniversityLanzhou 73000China

Thermokarst lake formation accelerates permafrost degradation due to climate warming,thereby releasing significant amounts of carbon into the atmosphere,complicating hydrological cycles,and causing environmental ***,the energy transfer mechanism from the surface to the sediment of thermokarst lakes remains largely unexplored,thereby limiting our understanding of the magnitude and duration of biogeochemical processes and hydrological ***,herein,a typical thermokarst lake situated in the center of the Qinghai-Tibet Plateau(QTP)was selected for observation and energy budget *** results showed that the net radiation of the thermokarst lake surface was 95.1,156.9,and 32.3 W m^(-2) for the annual,ice-free,and ice-covered periods,respectively,and was approximately 76%of the net radiation consumed by latent heat *** in heat storage in the thermokarst lake initially increased from January to April,then decreased from April to December,with a maximum change of 48.1 W m^(-2) in *** annual average heat fuxes from lake water to sediments were 1.4 W m^(-2);higher heat fluxes occurred during the ice-free season at a range of 4.9-12.0 W m^(-2).The imbalance between heat absorption and release in the millennium scale caused the underlying permafrost of the thermokarst lake to completely *** present,the ground temperature beneath the lake bottom at a depth of 15 m has reached 2.0℃.The temperatures and vapor-pressure conditions of air and lake surfaces control the energy budget of the thermokarst *** findings indicate that changes in the hydrologic regime shifts and biogeochemical processes are more frequent under climate warming and permafrost degradation.

关键词： Qinghai-Tibet Plateau Thermokarst lake Energy budget Permafrost degradation Hydrological cycle

Revealing the role of calcium ion intercalation of hydrated vanadium oxides for aqueous zinc-ion batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第8期95卷 9-19,I0001页

作者： Tao Zhou Xuan Du guo gao Key Laboratory for Thin Film and Micro Fabrication of the Ministry of Education School of Sensing Science and EngineeringSchool of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Exploring suitable high-capacity V_(2)O_(5)-based cathode materials is essential for the rapid advancement of aqueous zinc ion batteries(ZIBs).However,the typical problem of slow Zn^(2+)diffusion kinetics has severely limited the feasibility of such *** this work,unique hydrated vanadates(CaVO,BaVO)were obtained by intercalation of Ca^(2+)or Ba^(2+)into hydrated vanadium *** the CaVO//Zn and BaVO//Zn batteries systems,the former delivered up to a 489.8 mAh g^(-1)discharge specific capacity at 0.1 A g^(-1).Moreover,the remarkable energy density of 370.07 Wh kg^(-1)and favorable cycling stability yard outperform BaVO,pure V_(2)O_(5),and many reported cathodes of similar ionic intercalation *** addition,pseudocapacitance analysis,galvanostatic intermittent titration(GITT)tests,and Trasatti analysis revealed the high capacitance contribution and Zn^(2+)diffusion coefficient of CaVO,while an in-depth investigation based on EIS elucidated the reasons for the better electrochemical performance of ***,ex-situ XRD,XPS,and TEM tests further demonstrated the Zn^(2+)insertion/extraction and Zn-storage mechanism that occurred during the cycle in the CaVO//Zn battery *** work provides new insights into the intercalation of similar divalent cations in vanadium oxides and offers new solutions for designing cathodes for high-capacity aqueous ZIBs.

关键词： Aqueous zinc ion batteries Cathode materials Ion pre-intercalation Vanadium oxides Energy storage mechanism

Effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on viscosity and structure of slag for pyrometallurgical processing of spent automotive catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第3期31卷 608-621页

作者： Zhe Wang Qi-long Wei Cheng-bin Shi zhan-cheng guo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on the viscosity and structure of the CaO-Al_(2)O_(3)-SiO_(2)-6MgO-1.5ZrO_(2)-1.5CeO_(2) slag was *** results show that with the increase in Al_(2)O_(3)/SiO_(2) mass ratio,the viscous flow units within the slag gradually change from Si-O-Si to Al-O-Al and ***,the substitution of Al_(2)O_(3) for SiO_(2) leads to the transformation of Si-O bonds towards weaker Al-O bonds,which weaken the bond strength of the aluminosilicate networks,thus leading to a decrease in the viscosity of *** increase in CaO content effectively promotes the depolymerization of the aluminosilicate networks,resulting in a significant decrease in the viscosity of the *** slag with Al_(2)O_(3)/SiO_(2) of 0.7-1.5 and CaO of 30 wt.%shows promise as the reference slag system for the Fe-collection smelting of spent automotive catalysts due to its good comprehensive performance.

关键词： Aluminosilicate slag Al_(2)O_(3)/SiO_(2)mass ratio CaO content Viscosity Slag structure

A comprehensive survey of federated transfer learning: challenges, methods and applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第6期18卷 186356-186356页

作者： guo Wei ZHUANG Fuzhen zhan Xiao TONG Yiqi DONG Jin Institute of Artificial Intelligence Beihang University SKLSDE School of Computer Science Beihang University School of Computer Science and Technology Shandong University Beijing Academy of Blockchain and Edge Computing

Federated learning (FL) is a novel distributed machine learning paradigm that enables participants to collaboratively train a centralized model with privacy preservation by eliminating the requirement of data sharing. In practice, FL often involves multiple participants and requires the third party to aggregate global information to guide the update of the target participant. Therefore, many FL methods do not work well due to the training and test data of each participant may not be sampled from the same feature space and the same underlying distribution. Meanwhile, the differences in their local devices (system heterogeneity), the continuous influx of online data (incremental data), and labeled data scarcity may further influence the performance of these methods. To solve this problem, federated transfer learning (FTL), which integrates transfer learning (TL) into FL, has attracted the attention of numerous researchers. However, since FL enables a continuous share of knowledge among participants with each communication round while not allowing local data to be accessed by other participants, FTL faces many unique challenges that are not present in TL. In this survey, we focus on categorizing and reviewing the current progress on federated transfer learning, and outlining corresponding solutions and applications. Furthermore, the common setting of FTL scenarios, available datasets, and significant related research are summarized in this survey.

关键词： federated transfer learning federated learning transfer learning survey