检索结果-南通市图书馆

Science China Chemistry 2024年第10期67卷 3397-3405页

作者： Yidan Xing Rongrong Yu Mingdong Jiao Ting Wang Xianjie Fang Shanghai Key laboratory for Molecular Engineering of Chiral Drugs School of Chemistry and Chemical EngineeringShanghai Jiao Tong University Key laboratory of Organosilicon Chemistry and material Technology of Ministry of Education Key Laboratory of Organosilicon Material Technology of Zhejiang ProvinceCollege of MaterialChemistry and Chemical EngineeringHangzhou Normal University

The transition-metal-catalyzed migratory functionalization has emerged as a robust protocol for the building of C–C bonds remote from the “initiation” position. However, a similar strategy for the construction of quaternary carbon centers is still underdeveloped and only a limited number of reports exist. Herein, we report a nickel-catalyzed migratory hydrocyanation of unconjugated dienes to construct remote cyano-substituted quaternary carbon centers. This transformation features exceptional regioselectivity, mild reaction conditions, broad substrate scope and high yields. The synthetic utility of this method has been highlighted by a series of product derivatizations, and the potential of this transformation has been extended to synthesize TRPV1 antagonist and the key intermediate in the total synthesis of quebrachamine. Density functional theory(DFT) studies unveiled that the specific catalytic pocket assumed a significant role in the selective formation of cyano-substituted quaternary carbon centers.

关键词： chain-walking regioselectivity remote cyanation quaternary carbon centers unconjugated dienes

Microstructure and Internal Friction Behavior of Laser 3D Printed Fe-Based Amorphous Composites

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 196-204页

作者： Shuilong Huang Qingjun Chen Li Ji Kan Wang Guosheng Huang School of material Science and Engineering Nanchang Hangkong UniversityNanchang330063China State Key laboratory for Marine Corrosion and Protection Luoyang Ship Material Research Institute(LSMRI)Qingdao266237China

Laser 3D printing,also known as laser additive manufacturing(LAM),is favored for its ability to form bulk metallic glass(BMG)and its composite materials(BMGcs)with freeform *** this work,two different kinds of Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2)amorphous coatings(A and B)were prepared by using LAM technology under air-and water-cooled conditions,respectively;meanwhile,to reduce the cracks generated due to the residual thermal stresses,coating C obtained by air-sweep annealing of B with a low energy-density *** morphology and amorphous content and microstructure of the coatings were investigated,the results show many cracks in coating B deposited under water-cooled conditions,and its microstructure shows an amorphous-crystal-nanocrystalline mixed *** was suppressed in coating C,obtained by air-sweep annealing based on coating B,but the amorphous content was reduced from 32.6 to 13.4%.And the hardness and corrosion resistance of the coating will increase with the increase in the amorphous ***,the internal friction behavior of a BMGcs was prepared on the basis of the process of sample C is compared with that of as-cast amorphous *** results show that the low temperature internal friction behavior of BMGcs is affected by the defects produced during printing,and the high temperature internal friction behavior is affected by the precipitated hard phase.

关键词： Laser 3D printing Amorphous coating Microstructure Corrosion resistance Internal friction behavior

Multiporphyrinic architectures:Advances in structural design for photodynamic therapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2024年第1期5卷 67-84页

作者： Yuwei Gao Yan Li Zhengwei Xu Shuangjiang Yu Junqiu Liu Hongcheng Sun College of material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of EducationHangzhou Normal UniversityHangzhouChina

Rationally designed multiporphyrinic architectures for boosting photodynamic therapy(PDT)have attracted significant attentions recently years due to their great potential for light-mediated generation of reactive oxygen ***,there is still a gap between the structure design and their PDT performance for biomedical *** tutorial review provides a historical overview on(i)the basic concept of PDT for deeply understanding the porphyrin-mediated PDT reactions,(ii)developing strategies for constructing porphyrinic architectures,like nanorings,boxes,metal-organic frameworks(MOFs),covalent-organic frameworks(COFs),vesicles,etc.,where we classified into the following three categories:multiporphyrin arrays,porphyrinic frameworks,and others porphyrin assemblies,(iii)the various application scenarios for clinical cancer therapy and antibacterial ***,the existing challenges and future perspectives on the innovation of porphyrinic architectures for clinical PDT applications are mentioned in the end ***,the porphyrinic nanomaterials with atomically precise architectures provide an ideal platform for investigating the relationship between structures and PDT outputs,design of personalized“all-in-one”theranostic agents,and the popularization and application in wider biomedical fields.

关键词： covalent-organic frameworks(COFs) metal-organic frameworks(MOFs) multiporphyrin arrays photodynamic therapy(PDT) porphyrinic architectures

Volume-averaged modeling of multiphase solidification with equiaxed crystal sedimentation in a steel ingot

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第3期21卷 229-238页

作者： Xiao-lei Zhu Shuang Cao Rui Guan Ji Yang Zhe Ning Xin-gang Ai Sheng-li Li Xin-cheng Miao The key laboratory of material Forming and Structure Property Control Anshan 114051LiaoningChina State Key laboratory of Metal material for Marine Equipment and Application Anshan 114009LiaoningChina School of materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

Macrosegregation is a critical factor that limits the mechanical properties of *** impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a *** improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian *** this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered *** sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the ***,noticeable positive macrosegregation occurs in the area of final solidification in the *** improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting *** mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.

关键词： ingot casting multiphase solidification model equiaxed crystal sedimentation microstructure macrosegregation

维普期刊数据库

Rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)} with fast-responsive photochromism and switchable luminescence properties

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第2期42卷 286-292,I0003页

作者： Hong Cui Yanli Yang Xue Bai Xu Han Wensha Zhang Ying Lu Shuxia Liu Key laboratory of Polyoxometalate and Reticular material Chemistry of the Ministry of Education College of ChemistryNortheast Normal UniversityChangchun 130024China

Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution *** analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic ***,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f ***,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μ***,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.

关键词： Inorganic-organic hybrid Keggin-type polyoxometalates Rare earths Photochromism Photoluminescence

维普期刊数据库

Grain boundary-induced drastic sensing performance enhancement of Fe2O3 gas sensors for acetone

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第9期43卷 4412-4424页

作者： Tian-Jun Hu Yi-Fan Li Yu-Zhu Tian Ying Wang Ya-Ru Chen Jun-Ming Zhang Er-Gui Luo Jian-Feng Jia Key laboratory of Magnetic Molecules & Magnetic Information materials Ministry of Education School of Chemical and Material ScienceShanxi Normal University

Exploring the structure-activity relationship between the performance of gas sensors and the structure of semiconductor metal oxide （SMO） nanomaterials is crucial for understanding and designing gas-sensing materials and overcoming the application limitations of SMO-based gas *** of a single SMO microstructure provides a promising solution to address this scientific problem due to its controllable *** this study,we control the grain boundary （GB） density of Fe2O3nanomaterials using a simple solvothermal *** have similar chemical compositions and crystal phases,providing an ideal platform for studying the influence of the GB density on the gas-sensing ***-sensing tests showed that the Fe2O3-1 sensor with medium GB density and the Fe2O3-2 sensor with high GB density had higher sensitivity and selectivity than the Fe2O3-0 sensors with low GB density before reaching the optimal operating ***,when the GB density increased,the response to acetone decreased slightly,whereas the optimal operating temperature *** work highlights the unique performance of the GB density in enhancing the gas sensitivity of a single SMO.

关键词： Charge transfer Gas sensors Grain boundary (GB) density Oxygen adsorption Semiconductor metal oxide (SMO)

Polyoxometalate as the assembly material to self-assembled Ni(OH)_(2) nanosheets with electrocatalytic performance

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7061-7067页

作者： Danyang He Tianyang Li Luozhen Jiang Fei Wang Zihao Xing Nan Wang Zhiyu Jia Guo-Yu Yang Key laboratory of Cluster Science Ministry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China Shanghai Advanced Research Institute Chinese Academy of ScienceShanghai 201210China Key laboratory of Polyoxometalate and Reticular material Chemistry of Ministry of Education Facluty of ChemistryNortheast Normal UniversityChangchun 130024China

Developing non-noble metal-based electrocatalyst with high catalytic activity is essential for advancing hydrogen energy *** study introduces a hydrothermal method for synthesizing order Ni(OH)_(2) nanosheets,with H_(3)O_(40)PW_(12)(denoted as PW_(12))loaded onto reduced graphene oxide(rGO)coated on nickel foam(referred to as PW_(12)-Ni(OH)_(2)/rGO).This method contrasts with the electrodeposition of Ni(OH)_(2),where PW_(12) is added to the synthetic system to direct the assembly and morphology of the Ni(OH)_(2) through a hydrothermal *** this work,the nickel foam acts dual roles as both the substrate and the source of nickel for the formation of Ni(OH)_(2).The PW_(12)-Ni(OH)_(2)/rGO nanosheets,when successfully prepared and loaded onto the nickel foam(NF),exhibited superior electrocatalytic activity for the hydrogen evolution reaction(HER)in an alkaline electrolyte,achieving a current density of 10 mA·cm^(-2) at an overpotential of 69 ***,we endeavored to expand the application of this material towards the oxygen evolution reaction(OER)by preparing PW_(12)-(Fe/Co)Ni(OH)_(2)/rGO through the addition of metal *** nanocomposite displayed outstanding electrocatalytic activity in alkaline electrolytes,with a current density of 10 mA·cm^(-2)at an overpotential of 211 mV,and demonstrated excellent stability over a 50 h period in a 1 M KOH *** results presented in this paper offer an effective strategy for the preparation of polyoxometalate-based inorganic materials with diverse functionalities,applicable to both HER and OER.

关键词： polyoxometalate Ni(OH)_(2) assembly hydrogen evolution reaction oxygen evolution reaction

A soft-contact hybrid electromagnetic–triboelectric nanogenerator for self-powered water splitting towards hydrogen production

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7期17卷 6567-6574页

作者： Fuxue Ma Yingjie Wu Shuge Dai Pei Lin Junlu Sun Lin Dong Key laboratory of material Physics of Ministry of Education and School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450000China

The effective acquisition of hydrogen energy from the ocean offers a promising sustainable solution for increasing global energy ***,a self-powered high-efficient hydrogen generation system is proposed by integrating a triboelectric–electromagnetic hybrid nanogenerator(TEHG),power management circuit(PMC),and an electrolytic *** the wind triggering,as-fabricated TEHG can effectively convert breeze energy into electric energy,which demonstrates a high output current of 20.3 mA at a speed rotation of 700 rpm and the maximal output power of 13.8 mW at a load of 10 MΩ.Remarkably,asdesigned self-powered system can perform a steady and continuous water splitting to produce hydrogen(1.5μL·min^(−1))by adding a matching capacitor between the PMC and electrolytic *** the circuit,the capacitor can not only function as a charge compensation source for water splitting,but also stabilize the working *** other self-powered water splitting systems,the proposed system does not need catalysts or the complex electrical energy storage/release process,thus improving the hydrogen production efficiency and reducing the *** work provides an effective strategy for clean hydrogen energy production and demonstrates the huge potential of the constructed self-powered system toward carbon neutralization.

关键词： wind energy harvester hybrid nanogenerator energy conversion and management hydrogen energy production

Recent progress of cobalt-based electrocatalysts for water splitting: Electron modulation, surface reconstitution, 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

Nano Research 2024年第4期17卷 2234-2269页

作者： Zhijian Liang Di Shen Lei Wang Honggang Fu Key laboratory of Functional Inorganic material Chemistry Ministry of Education of the People’s Republic of ChinaHeilongjiang UniversityHarbin 150080China

Electrocatalytic water splitting is an essential and effective means to produce green hydrogen energy structures,so it is necessary to develop non-precious metal catalysts to replace precious ***-based catalysts present effective alternatives due to the diverse valence states,adjustable electronic structures,and plentiful *** this review,the catalytic mechanisms of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)for electrocatalytic water splitting are ***,the synthesis strategies of various cobalt-based catalysts are systematically summarized,followed by the relationships between the structure and performance ***,the effects of d-band center and spin regulation for cobalt-based catalysts are also ***,the dynamic electronic and structural devolution of cobalt-based catalysts are elucidated by combining a series of in-situ ***,we highlight the challenges and future developed directions of cobalt-based catalysts for electrocatalytic water splitting.

关键词： cobalt-based electrocatalysts water splitting electron modulation surface reconfiguration

Progress and prospect of Pt-based catalysts for electrocatalytic hydrogen oxidation reactions

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3期17卷 960-981页

作者： Xu Zhang Ying Xie Lei Wang Key laboratory of Functional Inorganic material Chemistry Ministry of Education of the People’s Republic of ChinaHeilongjiang UniversityHarbin 150080China

To achieve the goals of the peak carbon dioxide emissions and carbon neutral,the development and utilization of sustainable clean energy are extremely *** fuel cells are an important system for converting hydrogen energy into electrical ***,the slow hydrogen oxidation reaction(HOR)kinetics under alkaline conditions has limited its ***,elucidating the catalytic mechanism of HOR in acidic and alkaline media is of great significance for the construction of highly active and stable *** terms of practicality,Pt is still the primary choice for commercialization of fuel *** the above basis,we first introduced the hydrogen binding energy theory and bifunctional theory used to describe the HOR activity,as well as the pH *** that,the rational design strategies of Pt-based HOR catalysts were systematically classified and summarized from the perspective of activity *** addition,we further emphasized the importance of theoretical simulations and in situ characterization in revealing the HOR mechanism,which is crucial for the rational design of ***,the practical application of Pt-based HOR catalysts in fuel cells was also *** closing,the current challenges and future development directions of HOR catalysts were *** review will provide a deep understanding for exploring the mechanism of highly efficient HOR catalysts and the development of fuel cells.

关键词： Pt-based catalysts hydrogen oxidation reaction(HOR) electrocatalytic mechanism hydrogen binding energy theory bifunctional theory