检索结果-南通市图书馆

Enhanced optical absorption in semiconductor nano- particles enabled by nearfield dielectric scattering

在线全文

学校读者我要写书评

暂无评论

Nano Research 2017年第4期10卷 1292-1301页

作者： Kowsalya D. Rasamani jonathan j. Foley IV Brittney Beidelman Yugang sun Department of Chemistry Temple University 1901 North 13th Street Philadelphia Pennsylvania 19122 USA Department of Chemistry William Paterson University 300 Pompton Road Wayne New Jersey 07470 USA Department of Physics Bryn Mawr College 101 North Merion Avenue Bryn Mawr Pennsylvania 19010 USA

The optical absorption of semiconducting AgBr nanocubes is significantly increased by up to 5 times in the measured spectral range when they are bonded to the surface of dielectric SiO2 nanospheres through electrostatic interaction. The absorption enhancement factor depends on the wavelength and the size of the SiO2 nanoparticles （NPs）. Finite-difference time-domain calculations provide the nearfield intensity mapping of a heterostructure that is composed of a AgBr nanocube in close contact with a SiO2 nanosphere. The electric-field distributions indicate the field enhancement near the SiO2/AgBr interface due to light scattering and absorption enhancement in the AgBr nanocube, implying that the enhanced scattering nearfield increases the absorption cross section of the AgBr nanocube. The absorption cross-section spectra calculated using Mie theory agree with the experimental observations. This discovery sheds light on the utilization of dielectric spherical particles to increase the absorption in semiconductor NPs, thus improving the light-harvesting efficiency for solar-energy conversion.

关键词： enhanced scattering nearfield dielectric scattering absorption enhancement Mie theory

TWO NORDITERPENOID ALKALOIDS FROM ACONITUM LEUCOSTOMUM

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 Chemical Letters 1996年第8期7卷 725-728页

作者： Yue, jM Xu, j sun, HD Chen, SN Chen, YZ ACAD SINICA KUNMING INST BOTLAB PHYTOCHEMKUNMING 650204PEOPLES R CHINA LANZHOU UNIV DEPT CHEMLANZHOU 730000PEOPLES R CHINA

Two new norditerpenoid alkaloids leucostines A (1) and B (2) have been isolated from the soot of Aconitum leucostomum. Their structures were elucidated on the basis of spectral data and chemical evidence.

关键词：

Five New Compounds from Clerodendrum Indicum

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1997年第2期8卷 129-132页

作者： Tian, j Zhao, QS Zhang, Hj Lin, ZW sun, HD ACAD SINICA KUNMING INST BOTLAB PHYTOCHEMKUNMING 650204PEOPLES R CHINA

From the aerial parts of Clerodendrum indicum, bye new compounds, cleroindicins B-F (1-5) were isolated and their structures identified by spectral method.

关键词： HZ Five New Compounds from Clerodendrum Indicum

FORMATION OF Fe-N COMPOUNDS BY LASER NITRIDATION IN AN ATMOSPHERIC AMBIENT

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2003年第2期16卷 139-144页

作者： Y.L.Yang F.j.sun D.Zhang College of Science Northeastern UniversityShenyang 110004ChinaCollege of ScienceNortheastern UniversityShenyang 110004ChinaCollege of ScienceNortheastern UniversityShenyang 110004China

The formation of Fe-N compounds by laser nitriding in an atmospheric ambient was reported. By CW-CO2 laser irradiation on pure ferrite iron in the atmospheric ambient, Fe-N compounds (including Fe2N, .Fe3AT and Fe4N) are formed as a result of a laser-enhanced and temperature-enhanced reactions. The samples were analyzed with X-ray diffraction. It is found that the laser power density, scanning speed and nitrogen temperature are the main factors influencing the formation of Fe-N compounds. Nitrogen can be activated by pre-heating at some temperature. Nitrogen activation and sample surface melting by CW-CO2 laser greatly enhance the reaction between the sample surface and nitrogen beam. After annealing at 500℃for 3h, some Fe2N and Fe3N converted into more stable Fe4N.

关键词： laser nitriding nitride Fe-N compound

RE-ENGINEERING TRANSFORMER MAINTENANCE PROCESSES TO IMPROVE CUSTOMIZED SERVICE DELIVERY

在线全文

学校读者我要写书评

暂无评论

journal of Systems Science and Systems Engineering 2011年第3期20卷 323-345页

作者： Amy j.C. TRAPPEY Yong sun Charles V. TRAPPEY Lin MA Department of Industrial Engineering and Engineering Management National Tsing Hua University Taiwan China Department of Industrial Engineering and Management National Taipei University of Technology Taiwan China School of Engineering Systems Queensland University of Technology Australia Department of Management Science National Chiao Tung University Taiwan China

The outage of a transformer in a power generation system will generally result in a shutdown of the entire system. Consequentially, large amounts of revenue are lost to the plant owner with a substantial negative impact on the civil community and industrial customers. This paper analyzes the current maintenance practices （i.e., an as-is process model） of a transformer manufacturing company, which provides maintenance services to power generation plants and reports the major weaknesses in current business practices. The maintenance weaknesses include isolated processes and paper based information communication. These inefficient processes result in service delays, cost increases, and inappropriate responses to customers＇ specific requests and complaints. To improve the efficiency and flexibility of the entire transformer maintenance service system, an e-integration approach is implemented with three key tasks. First, the current business processes are re-engineered to provide an improved （to-be） business model. Then, we replace paper based documentation methods with an electronic filing system for efficient and cost-effective information exchange. Afterward, the improved process model is implemented as an Internet based system to enhance the interactions among the transformer manufacturer, end-users, and service contractors for customized maintenance services. The case study demonstrates that implementing the e-integration approach increases the efficiency and effectiveness of the customized maintenance services.

关键词： Business Processes Reengineering (BPR) asset maintenance power industry after-sales services transformers engineering

Rotational and translational domains of beta precipitate in aged binary Mg-Ce alloys

在线全文

学校读者我要写书评

暂无评论

journal of Magnesium and Alloys 2021年第3期9卷 1039-1056页

作者： B.Z.sun H.X.Zhang Y.Dong j.X.Ren Y.Tian G.M.Xie j.Tan Y.H.sun Na Xiao School of Materials Science and Engineering Northeastern UniversityShenyang 110819China State Key Lab Rolling&Automat Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819China Analytical and Testing Center Northeastern UniversityShenyang 110819China

The structural evolution fromβ_(1)(Mg_(3)Ce)toβ(Mg_(12)Ce)precipitates,which takes place at the over-aged stage of binary Mg-Ce alloys,are investigated by high-angle annular dark-field scanning transmission electron *** structural transformation mainly occurs in the{111}_(β1)crystallographic planes,where the newly formedβlattices exhibit two categories of domain structures,namely rotational and translational *** rotational domain is composed of threeβdomains(β_(RA),β_(RB)andβ_(RC)),which are related by a 120°rotation with respect to each other around the 111_(β1)axis of theirβ_(1)parent ***{111}_(β1)crystallographic planes can provide four sets of sublattices with the same orientation for an initial nucleation ofβ*** leads to the formation of four translationalβdomains(β_(TA),β_(TB),β_(TC)andβ_(TD)),among which any two differ by a vector of 1/6112_(β1).We deduce theoretically that there exist twenty-fourβdomains during this ***,considering the interfacial misfit,only one-third of domains can grow up and eventually formsβ***,a majority ofβribbons overlap partiallyβ_(1)plate,which is beneficial to relax interfacial strain amongβ,β_(1)andα-Mg matrix(α/β/β_(1)).The configuration of multipleβdomains can effectively regulate interfacial misfit ofα/βandβ/β_(1),which are responsible for enhancing the hardness and strength of Mg-Ce ***,this study aims to provide some clues to improve the over-aged performance of magnesium alloys by constructingβdomains and optimizing theα/β/β_(1)interface.

关键词： Magnesium alloys HAADF-STEM Rotational domain Translational domain Phase transition Interfacial misfit

An extraordinary-performance gradient nanostructured Hadfield manganese steel containing multi-phase nanocrystalline-amorphous core-shell surface layer by laser surface processing

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2023年第3期134卷 209-222页

作者： Wanting sun jiasi Luo Yim Ying Chan j.H.Luan Xu-Sheng Yang Research Institute for Advanced Manufacturing Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomHong KongChina Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center The Hong Kong Polytechnic UniversityHung HomHong KongChina Department of Materials Science and Engineering City University of Hong KongHong KongChina

Reducing grain size(*** the fraction of grain boundaries)could effectively strengthen nanograined metals but inevitably sacrifices the ductility and possibly causes a strengthening-softening transition below a critical grain *** this work,a facile laser surface remelting-based technique was employed and optimized to fabricate a∼600μm-thick heterogeneous gradient nanostructured layer on an austenitic Hadfield manganese steel,in which the average grain size is gradually decreased from∼200μm in the matrix to only∼8 nm in the nanocrystalline-amorphous core-shell topmost ***-scale microstructural characterizations dissected the gradient refinement processes along the gradient direction,*** from the dislocations activities and twinning in sub-region to three kinds of martensitic transformations,and finally a multi-phase nanocrystalline-amorphous core-shell structural *** tests(***,bulk-specimen tensile,and micro-pillar compression)were conducted along the gradient *** confirms a tensile strength of∼1055 MPa and ductility of∼10.5%in the laser-processed ***,the core-shell structural surface maintains ultra-strong(tensile strength of∼1.6 GPa,micro-pillar compressive strength of∼4 GPa at a strain of∼8%,and nanoindentation hardness of∼7.7 GPa)to overcome the potential strengthening-softening *** significant strengthening effects are ascribed to the strength-ductility synergetic effects-induced extra work hardening ability in gradient nanostructure and the well-maintained dislocation activities inside extremely refined nanograins in the multi-phase nanocrystalline-amorphous core-shell structural surface,which are evidenced by atomic-scale observations and theoretical *** study provides a unique hetero-nanostructure through a facile laser-related technique for extraordinary mechanical performance.

关键词： Laser surface processing Hadfield manganese steel Gradient nanostructure Nanocrystalline-amorphous Martensitic transformation

Perpulmonary Device Closure of Patent Ductus Arteriosus with Minimum Diameter More Than 4 mm in Infants

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Congenital Heart Disease 2022年第4期17卷 437-445页

作者： Shibin sun Geoffrey j.Changwe Zeeshan Farhaj Hongxin Li Yuekun sun Zhongzheng Kong Department of Cardiovascular Surgery Shandong Qianfoshan HospitalCheeloo College of MedicineShandong UniversityJinanChina Department of Cardiovascular and Thoracic Surgery The National Heart HospitalLusakaZambia

Background:Closure of large patent ductus arteriosus(PDA)in older children has been accomplished using surgical and percutaneous techniques with remarkable ***,outcomes amongst infants have been variable with several *** we describe a novel minimally invasive technique,a product of mini-thoracotomy and traditional percutaneous technique skills,accomplished exclusively under echocardiography ***:Symptomatic infants with a significant left-to-right shunt from PDA measuring more than 4 mm were *** symptoms were varying degrees of tachypnea,tachycardia,heart failure,failure to thrive,recurrent respiratory tract infections,or intensive care unit treatment for a longer *** a left parasternal mini-thoracotomy,two parallel purse-string sutures were placed on the pulmonary *** purse-string circle puncture,under exclusively transesophageal echocardiography guidance,a device secured to the safety-suture was implanted on the ascending aorta via pulmonary trunk using a specially designed *** safety-suture prevented device migration in case of *** basic demographics,PDA size,device size and type,intrapulmonary manipulation time,operation time,PDA parameters(length,diameter,type of duct),redeployment of the device,residual shunt,and retention of safety-suture were all recorded and *** follow-up was done with transthoracic echocardiography on the 2^(nd)postoperative day,1,3,6,and 12 months,and yearly ***:Fifty-two infants with a mean age of 8 months±2.8 months(Interquartile range=0)underwent Perpulmonary device closure of *** PDA occlusion was accomplished event-free in all *** mean PDA,mean device,and mean operation time were 5.6 mm±1.4 mm,7.9 mm±1.7 mm,and 61.2 min±12.9 min,*** immediate acceptable residual shunt was noted among 3 subjects and disappeared at a 1-month *** infants had retained safety-suture for added ***

关键词： Patent ductus arteriosus perpulmonary device closure transesophageal echocardiography infant minimally invasive surgery

Automated generation and ensemble-learned matching of X-ray absorption spectra

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2018年第1期4卷 566-574页

作者： Chen Zheng Kiran Mathew Chi Chen Yiming Chen Hanmei Tang Alan Dozier joshua j.Kas Fernando D.Vila john j.Rehr Louis F.j.Piper Kristin A.Persson Shyue Ping ong Department of NanoEngineering University of California San Diego9500 Gilman DriveMail Code 0448La JollaCA 92093-0448USA Department of Materials Science University of California BerkeleyBerkeleyCA 94720USA Division of Applied Research and Technology National Institute for Occupational Safety and HealthCenters for Disease ControlCincinnatiOH 45226USA Department of Physics University of WashingtonSeattleWA 98195USA Department of Physics Applied Physics and AstronomyBinghamton UniversityBinghamtonNY 13902USA Materials Science&Engineering Binghamton UniversityBinghamtonNY 13902USA

X-ray absorption spectroscopy(XAS)is a widely used materials characterization technique to determine oxidation states,coordination environment,and other local atomic structure *** of XAS relies on comparison of measured spectra to reliable reference ***,existing databases of XAS spectra are highly limited both in terms of the number of reference spectra available as well as the breadth of chemistry *** this work,we report the development of XASdb,a large database of computed reference XAS,and an Ensemble-Learned Spectra IdEntification(ELSIE)algorithm for the matching of *** currently hosts more than 800,000 K-edge X-ray absorption near-edge spectra(XANES)for over 40,000 materials from the open-science Materials Project *** discuss a high-throughput automation framework for FEFF calculations,built on robust,rigorously benchmarked *** is a computer program uses a real-space Green’s function approach to calculate X-ray absorption *** will demonstrate that the ELSIE algorithm,which combines 33 weak“learners”comprising a set of preprocessing steps and a similarity metric,can achieve up to 84.2% accuracy in identifying the correct oxidation state and coordination environment of a test set of 19 K-edge XANES spectra encompassing a diverse range of chemistries and crystal *** XASdb with the ELSIE algorithm has been integrated into a web application in the Materials Project,providing an important new public resource for the analysis of XAS to all materials ***,the ELSIE algorithm itself has been made available as part of veidt,an open source machine-learning library for materials science.

关键词： matching XANES ensemble