检索结果-南通市图书馆

Alloyed Pt-Sn nanoparticles on hierarchical nitrogen-doped carbon nanocages for advanced glycerol electrooxidation

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第5期17卷 4055-4061页

作者： Jietao Jiang Liqi Zhou Fengfei Xu Guanghai Chen Xiaoyu Liu zhen shen Lijun Yang Qiang Wu Xizhang Wang zheng Hu Key Laboratory of Mesoscopic Chemistry of MOE Jiangsu Provincial Laboratory for NanotechnologySchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Glycerol is an alternative sustainable fuel for fuel cells,and efficient electrocatalyst is crucial for glycerol oxidation reaction(GOR).The promising Pt catalysts are subject to the inadequate capability of C-C bond cleavage and the susceptibility to poisoning.Herein,Pt-Sn alloyed nanoparticles are immobilized on hierarchical nitrogen-doped carbon nanocages(hNCNCs)by convenient ethylene glycol reduction and subsequent thermal reduction.The optimal Pt_(3)Sn/hNCNC catalyst exhibits excellent GOR performance with a high mass activity(5.9 A·mg_(Pt)^(-1)),which is 2.7 and 5.4 times higher than that of Pt/hNCNC and commercial Pt/C,respectively.Such an enhancement can be mainly ascribed to the increased anti-poisoning and C-C bond cleavage capability due to the Pt_(3)Sn alloying effect and Sn-enriched surface,the high dispersion of Pt_(3)Sn active species due to N-participation,as well as the high accessibility of Pt_(3)Sn active species due to the three-dimensional(3D)hierarchical architecture of hNCNC.This study provides an effective GOR electrocatalyst and convenient approach for catalyst preparation.

关键词： Pt_(3)Sn alloy hierarchical nitrogen-doped carbon nanocages glycerol electrooxidation anti-poisoning C-C bond cleavage

Self-supported NiFe-LDH nanosheets on NiMo-based nanorods as high-performance bifunctional electrocatalysts for overall water splitting at industrial-level current densities

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

Nano Research 2024年第5期17卷 3769-3776页

作者： Yan Zhang Biao Feng MingLei Yan zhen shen Yiqun Chen Jingyi Tian Fengfei Xu Guanghai Chen Xizhang Wang Lijun Yang Qiang Wu zheng Hu Key Laboratory of Mesoscopic Chemistry of Ministry of Education(MOE)and Jiangsu Provincial Lab for Nanotechnology School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China College of Water Conservancy and Hydropower Engineering Sichuan Agricultural UniversityYa’an 625014China

Efficient,durable and economic electrocatalysts are crucial for commercializing water electrolysis technology.Herein,we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-layered double hydroxide(NiFe-LDH)nanosheet arrays on the conductive NiMo-based nanorods deposited on Ni foam to form a three-dimensional(3D)architecture,which exhibits exceptional performances for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).In overall water splitting,only the low operation voltages of 1.45/1.61 V are required to reach the current density of 10/500 mA·cm^(-2),and the continuous water splitting at an industrial-level current density of 500 mA·cm^(-2) shows a negligible degradation(1.8%)of the cell voltage over 1000 h.The outstanding performance is ascribed to the synergism of the HER-active NiMo-based nanorods and the OER-active NiFe-LDH nanosheet arrays of the hybridized 3D architecture.Specifically,the dense NiFe-LDH nanosheet arrays enhance the local pH on cathode by retarding OH-diffusion and enlarge the electrochemically active surface area on anode,while the conductive NiMo-based nanorods on Ni foam much decrease the charge-transfer resistances of both electrodes.This study provides an efficient strategy to explore advanced bifunctional electrocatalysts for overall water splitting by rationally hybridizing HER-and OER-active components.

关键词： alkaline water splitting bifunctional electrocatalysts layered double hydroxides high durability industrial current densities

Atom-referenced and stabilized soliton microcomb

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

Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 2-8页

作者： Rui Niu Shuai Wan Tian-Peng Hua Wei-Qiang Wang zheng-Yu Wang Jin Li Zhu-Bo Wang Ming Li zhen shen Yu Robert Sun Shui-Ming Hu Brent ELittle Sai Tak Chu Wei Zhao Guang-Can Guo Chang-Ling Zou Yun-Feng Xiao Wen-Fu Zhang Chun-Hua Dong State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710119China CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China University of Chinese Academy of Sciences Beijing 100049China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Department of Physics and Materials Science City University of Hong KongHong Kong 999077China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China

For the applications of the frequency comb in microresonators,it is essential to obtain a fully frequency-stabilized microcomb laser source.In this study,we present a system for generating a fully atom-referenced stabilized soliton microcomb.The pump light around 1560.48 nm is locked to an ultra-low-expansion(ULE)cavity.This pump light is then frequency-doubled and referenced to the atomic transition of87Rb.The repetition rate of the soliton microcomb is injection-locked to an atomic-clockstabilized radio frequency(RF)source,leading to mHz stabilization at 1 s.As a result,all comb lines have been frequencystabilized based on the atomic reference and the ULE cavity,achieving a very high precision of approximately 18 Hz at 1 s,corresponding to the frequency stability of 9.5×10^(-14).Our approach provides a fully stabilized microcomb experiment scheme with no requirement of f-2f technique,which could be easily implemented and generalized to various photonic platforms,thus paving the way towards the ultraprecise optical sources for high precision spectroscopy.

关键词： microcavity frequency comb dissipative Kerr solitons fully stabilized microcomb

Research on a Monte Carlo global variance reduction method based on an automatic importance sampling method

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第5期35卷 200-215页

作者： Yi-sheng Hao zhen Wu shen-shen Gao Rui Qiu Hui Zhang Jun-Li Li Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging of Ministry of Education Beijing 100084China Nuctech Company Limited Beijing 100084China

Global variance reduction is a bottleneck in Monte Carlo shielding calculations.The global variance reduction problem requires that the statistical error of the entire space is uniform.This study proposed a grid-AIS method for the global variance reduction problem based on the AIS method,which was implemented in the Monte Carlo program MCShield.The proposed method was validated using the VENUS-Ⅲ international benchmark problem and a self-shielding calculation example.The results from the VENUS-Ⅲ benchmark problem showed that the grid-AIS method achieved a significant reduction in the variance of the statistical errors of the MESH grids,decreasing from 1.08×10^(-2) to 3.84×10^(-3),representing a 64.00% reduction.This demonstrates that the grid-AIS method is effective in addressing global issues.The results of the selfshielding calculation demonstrate that the grid-AIS method produced accurate computational results.Moreover,the grid-AIS method exhibited a computational efficiency approximately one order of magnitude higher than that of the AIS method and approximately two orders of magnitude higher than that of the conventional Monte Carlo method.

关键词： Monte Carlo Global variance reduction Reactor shielding Automatic importance sampling

Injectable chitosan hydrogels loaded with antioxidant agent as first-aid dressings for second-degree burn wounds

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第3期67卷 891-901页

作者： REN Hui ZHANG zhen LU KaiLun shen YuanYuan HE ChaoLiang CHEN XueSi CAS Key Laboratoryof Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Burn wounds are destructive skin traumas typically of irregular shape and large area. Prone to infection, they require frequent dressing replacement, and painless removal of dressings from burn wounds remains a major challenge. This study focuses on the dynamic characteristics and treatment difficulty of burn wounds. Hydrogel dressings based on glycol chitosan and propionaldehyde-or benzaldehyde-terminated 4-arm poly(ethylene glycol) were designed on the basis of Schiff base cross-linking networks. The hydrogels exhibited shape-adaptability, self-healing and fast-degradation properties, which makes these hydrogels suitable for burn wounds. Salvianolic acid B(SaB)-loaded hydrogel exhibited good antioxidant properties in vitro. In a rat model of deep second-degree burn wounds, the SaB-loaded hydrogel could quickly reduce wound temperature, regulate wound oxidant microenvironment, promote angiogenesis, and accelerate wound healing. Thus, the drug-loaded hydrogel shows significant potential as a first-aid dressing for treatment of burn wounds.

关键词： hydrogel dressing fast-degradation shape-adaptability stress relaxation burn wound treatment

Multi-carrier Tb/s silicon photonic coherent receiver

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第1期67卷 284-291页

作者： zhen WANG Xingfeng LI Jingchi LI Jian shen Yong ZHANG Yikai SU State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic EngineeringShanghai Jiao Tong University

We propose a silicon polarization-diversity coherent receiver for wavelength-multiplexing transmission without using the large-footprint arrayed waveguide grating(AWG).We have integrated our proposed coherent receiver on the silicon-on-insulator(SOI) platform for high-capacity transmission.In the proposed coherent receiver,high-frequency photocurrent signals from other wavelengths are suppressed by electrical low-pass filters.Moreover,the signal-signal beat interference(SSBI) generated from each wavelength is eliminated by the balanced detection.These two features lend to the proposed coherent receiver being free of the mm-scale AWG.We have demonstrated our proposed coherent receiver to detect a 1.12-Tb/s wavelength-division-multiplexed and polarization-division-multiplexed 16-ary quadrature amplitude modulation(PDM-16-QAM) signal.The compact footprint of the silicon chip promises small-form-factor receivers for future ultra-high-capacity coherent communication systems that require a high integration level and low fabrication cost.

关键词： silicon photonics optical receivers coherent communication wavelength-division-multiplexing(WDM) polarization-division-multiplexing(PDM)

Insight into vertical piezoelectric characteristics regulated thermal transport in van der Waals two-dimensional materials

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第2期43卷 770-779页

作者： Dong-Hai Wei E Zhou Jin-Yuan Xu Hui-Min Wang Chen shen Hong-Bin Zhang zhen-zhen Qin Guang-Zhao Qin State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082China Hunan Key Laboratory for Micro-Nano Energy Materials and Device and School of Physics and Optoelectronics Xiangtan UniversityXiangtan411105China Institute of Materials Science Technical University of DarmstadtAlarich-Weiss-Str.264287DarmstadtGermany School of Physics and Microelectronics Zhengzhou UniversityZhengzhou450001China

The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key role.Herein,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically undiscovered.The different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study cases.By performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic interactions.Consequently,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%strain.Our research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.

关键词： Thermal conductivity Piezoelectric effect 2D materials Bilayer BN Strain engineering

Research status and perspectives of MXene-based materials for aqueous zinc-ion batteries

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 1867-1885页

作者： Xiao-Yu Wang Qi-Hang Yang Xin-Yan Meng Meng-Meng zhen zhen-Zhong Hu Bo-Xiong shen School of Energy and Environmental Engineering Hebei University of Technology

Aqueous zinc-ion batteries (AZIBs) as green battery systems have attracted widespread attention in large-scale electrochemical energy storage devices,owing to their high safety,abundant Zn materials,high theoretica specific capacity and low redox potential.Nevertheless there are some thorny issues in AZIBs that hinder their practical application,such as low intrinsic electron conductivity,slow ion migration kinetics,zinc dendrites and side reactions.MXene-based materials with superior conductivity,large polar surface and abundant active sites can simultaneously serve as cathode materials,electrolyte additive and protection layer of anode to regulate redox reactions of AZIBs.Although various materials have been used to improve electrochemical performances of AZIBs there is a lack of in-depth discussion on the regulation mechanism of MXene-based materials for AZIBs.In this review,we elaborate the research progress of MXenebased materials in AZIBs,including their application in cathode materials and inhibition of zinc dendrites.Finally the future prospects and development directions of MXenebased materials that may improve performance of AZIBs are prospected.

关键词： MXene Aqueous zinc-ion batteries Composite materials Zinc dendrites

Sequential reactant water management by complementary multisite catalysts for surpassing platinum hydrogen evolution activity

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3期17卷 1232-1241页

作者： Yu Lin Defang Ding Shicheng Zhu Qunlei Wen Huangjingwei Li zhen Li Youwen Liu Yi shen China Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China State Key Laboratory of Materials Processing and Die&Mould Technology and School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Alkaline hydrogen evolution reaction(HER)offers a near-zero-emission approach to advance hydrogen energy.However,the activity limited by the multiple reaction steps involving H_(2)O molecules transfer,absorption,and activation still unqualified the thresholds of economic viability.Herein,we proposed a multisite complementary strategy that incorporates hydrophilic Mo and electrophilic V into Ni-based catalysts to divide the distinct steps on atomically dispersive sites and thus realize sequential regulation of the HER process.The Isotopic labeled in situ Raman spectroscopy describes 4-coordinated hydrogen bonded H_(2)O to be free H_(2)O passing the inner Helmholtz plane in the vicinity of the catalysts under the action of hydrophilic Mo sites.Furthermore,potential-dependent electrochemical impedance spectroscopy(EIS)reveals that electrophilic V sites with abundant 3d empty orbitals could activate the lone-pair electrons in the free H_(2)O molecules to produce more protic hydrogen,and dimerize into H_(2) at the Ni sites.By the sequential management of reactive H_(2)O molecules,NiMoV oxides multisite catalysts surpass Pt/C hydrogen evolution activity(49 mV@10 mA∙cm^(-2) over 140 h).Profoundly,this study provides a tangible model to deepen the comprehension of the catalyst–electrolyte interface and create efficient catalysts for diverse reactions.

关键词： hydrogen evolution activity complementary multisite catalysts sequential reactive water management interfacial water molecules