检索结果-南通市图书馆

Journal of Rare Earths 2022年第3期40卷 381-389,I0001页

作者： Xin Wang xiangping li Hongquan Yu Sai Xu Jiashi Sun lihong Cheng Xizhen Zhang Jinsu Zhang Yongze Cao Baojiu Chen School of Science Dalian Maritime UniversityDalian 116026China

A series of YNbO_(4):Bi^(3+) and YNbO_(4):Bi^(3+)/Er^(3+) phosphors were prepared by a conventional high temperature solid-state reaction *** results of XRD and Rietveld refinement confirm that monoclinic phase YNbO_(4)samples are *** down-/up-conversion luminescence of Er^(3+) ions was investigated under the excitation of ultraviolet light(327 nm)and near infrared light(980 nm).Under 327 nm excitation,broad visible emission band from Bi^(3+) ions and characteristic green emission peaks from Er^(3+) ions are simultaneously observed,while only strong green emissions from Er^(3+) ions are detected upon excitation of 980 *** emission enhancement is observed in down-/up-conversion luminescence processes by introducing Bi^(3+) ions into Er^(3+)-doped YNbO_(4)*** current versus up-conversion emission intensity study shows that two-photon processes are responsible for both the green and the red up-conversion emissions of Er^(3+)*** the study of the temperature sensing property of Er^(3+) ion,it is affirmed that the temperature sensitivity is sensitive to the doping concentration of Bi^(3+) *** comparing the experimental values of the radiative transition rate ratio of the two green emission levels of Er^(3+) ions and the theoretical values calculated by Judd-Ofelt(J-O)theory,it is concluded that the temperature sensing property of Er^(3+) ions is greatly affected by the energy level splitting.

关键词： YNbO_(4):Bi^(3+)/Er^(3+) Down-conversion luminescence Up-conversion luminescence Temperature sensing Rare earths

THE THREE-DIMENSIONAL STRESS INTENSITY FACTOR UNDER MOVING LOADS ON THE CRACK FACES

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1994年第1期7卷 54-67页

作者： li xiangping liu Chuntu(Institute of Mechanics,Academia Sinica.Beijing,100080,P.R.China) Institute of Mechanics Academia Sinica Beijing 100080 China

The dynamic stress intensity factor history for a half plane crack in an otherwise unbounded elastic body,with the crack faces subjected to a traction distribution consisting of two pairs of combined mode point loads that move in a direction perpendicular to the crack edge is *** analytic expression for the combined mode stress intensity factors as a function of time for any point along the crack edge is *** method of solution is based on the application of integral transform together with the Wiener-Hopf technique and the Cagniard-de Hoop method. Some features of the solution are discussed and graphical results for various point load speeds are presented.

关键词： Moving loads A half plane crack combined mode dynamic stress intensity factor

Band structure engineering in metal halide perovskite nanostructures for optoelectronic applications

在线全文

学校读者我要写书评

暂无评论

Nano Materials Science 2019年第4期1卷 268-287页

作者： Qingdong Ou Xiaozhi Bao Yinan Zhang Huaiyu Shao Guichuan Xing xiangping li liyang Shao Qiaoliang Bao Department of Materials Science and Engineering ARC Centre of Excellence in Future Low-Energy Electronics Technologies(FLEET)Monash UniversityClaytonVictoria3800Australia Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials Engineering(IAPME)University of MacaoMacaoPeople's Republic of China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou510632People's Republic of China Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen518055GuangdongPeople's Republic of China

Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and *** efforts on the controlled synthesis of perovskite nanostructures have been made towards potential device *** engineering of their band structures holds great promise in the rational tuning of the electronic and optical properties of perovskite nanostructures,which is one of the keys to achieving efficient and multifunctional optoelectronic *** this article,we summarize recent advances in band structure engineering of perovskite nanostructures.A survey of bandgap engineering of nanostructured perovskites is firstly presented from the aspects of dimensionality tailoring,compositional substitution,phase segregation and transition,as well as strain and pressure *** strategies of electronic doping are then reviewed,including defect-induced self-doping,inorganic or organic molecules-based chemical doping,and modification by metal ions or *** on the bandgap engineering and electronic doping,discussions on engineering energy band alignments in perovskite nanostructures are provided for building high-performance perovskite p-n junctions and *** last,we provide our perspectives in engineering band structures of perovskite nanostructures towards future low-energy optoelectronics technologies.

关键词： Band structure engineering Perovskite nanostructures Optoelectronic applications Doping Heterostructures

Speciation analysis of metals (Tl,Cd and Pb) in Tl-containing pyrite and its cinder from Yunfu Mine,China,by ICP-MS with sequential extraction

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2010年第1期29卷 113-119页

作者： WANG Chunlin CHEN Yongheng PAN Jianyang ZHANG Ping QI Jianying liU Juan li xiangping WANG Jin State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China School of Environmental Science and Engineering Guangzhou University Guangzhou 510006 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Hangzhou Environmental Monitoring Center Station Hangzhou 310007 China

The speciation of heavy metals such as thallium,cadmium and lead existing in pyrite and pyrite cinder was analyzed by ICP-MS with a sequential extraction *** distribution patterns of these metals including exchangeable,reducible,oxidizable and residual fractions were ***,Cd and Pb in pyrite and pyrite cinder samples from each extraction step were determined by inductively coupled plasma mass spectrometry(ICP-MS).Under the optimized instrumental conditions,detection limits of Tl,Cd and Pb in different matrices were within the range of 0.006-0.07 μg/L,and the relative standard deviations ranged from 0.8% to 1.2%.The accuracy of Tl,Cd and Pb determination was checked by analyzing two certified reference *** results demonstrate that trace Tl,Cd and Pb in the samples can be accurately *** sequential extraction results revealed that the percent contents of Tl,Cd and Pb in exchangeable,reducible and oxidizable fractions in pyrite cinder are different from those in pyrite and in pyrite ***,Cd and Pb mostly are distributed in residual ***,the mobility of metals in pyrite is higher than that in pyrite *** distributions of Tl,Cd and Pb in the non-residual fraction are not dominant in pyrite cinder,the total concentrations of them could not be ***,attention must be paid to the risk of potential pollution by pyrite cinder.

关键词：电感耦合等离子体质谱连续提取形态分析黄铁矿重金属铊镉铅

机械搅拌法制备颗粒增强铝基复合材料组织及性能研究

在线全文

学校读者我要写书评

暂无评论

轨道交通材料 2024年第3期3卷 1-5页

作者：李向平付康习夏少华张剑云龚家林中车戚墅堰机车车辆工艺研究所股份有限公司江苏常州213011

采用机械搅拌铸造法制备SiC_(p)/AlSi7Mg0.3铝基复合材料,通过金相组织观察(OM)、扫描电镜(SEM)、XRD等测试方法对SiC增强颗粒的预处理效果、铝基复合材料的显微组织及其力学性能进行研究。结果表明,高温氧化预处理工艺能够改善增强颗... 详细信息

采用机械搅拌铸造法制备SiC_(p)/AlSi7Mg0.3铝基复合材料,通过金相组织观察(OM)、扫描电镜(SEM)、XRD等测试方法对SiC增强颗粒的预处理效果、铝基复合材料的显微组织及其力学性能进行研究。结果表明,高温氧化预处理工艺能够改善增强颗粒表面属性,促进Al熔体对颗粒的润湿,最佳高温氧化预处理工艺为1200℃、4 h。随着机械搅拌速度和搅拌时间的增加,SiC颗粒在基体合金中的分布越来越均匀,当搅拌速度达到1200 r/min,搅拌时间为40 min时,SiC颗粒在基体中能够完全均匀分散,且被铝基体润湿,周围无孔洞缺陷存在。所制备的铝基复合材料铸态下抗拉强度达到207.7 MPa,屈服强度达到158.7 MPa,断后伸长率达到1.17%,布氏硬度达到119 HBW,其铸态下强度比ZAlSi7Mg合金材料提升了33%。

关键词：机械搅拌 SiC颗粒铝基复合材料预处理铸态

RULE OF DISTRIBUTION OF PHASE POINTS OF POLY-UNIT MOLECULES AND HOMOLOGOUS liNEAR LAW

在线全文

学校读者我要写书评

暂无评论

Science in China,Ser.B 1983年第7期26卷 673-688页

作者：李向平 Beijing Institute of Technology

The chain M-(A)_n-N or ring obtained by bonding n number of A’s with the same chemical structure in the same way is called the poly-unit molecule. Jiang Mingqian has discovered the famous homologous linear law for the poly-unit chain. Xu Guangxian and li Lemin have studied its quantum-chemical basis and put forward the new linear *** order to study further the basic quantum chemistry of the homologous linear law, it is necessary to have first a thorough knowledge of the orbital characteristics of the polyunit molecules. The author studied the orbitals and the energy levels of poly-unit molecules by using difference equations. Based on the past work the concept of phase points of orbital was established, and the rule of distribution of phase points was developed as well. It is found that the phase points of similar orbitals in the molecules of a homologous series appear to condense around a certain point. Based on this fact a theoretical proof of the homologous linear law was made.

关键词： line RULE OF DISTRIBUTION OF PHASE POINTS OF POLY-UNIT MOLECULES AND HOMOLOGOUS liNEAR LAW Poly As

Dual-band polarized upconversion photoluminescence enhanced by resonant dielectric metasurfaces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

elight 2023年第1期3卷 57-65页

作者： Ziwei Feng Tan Shi Guangzhou Geng Junjie li Zi-Lan Deng Yuri Kivshar xiangping li Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 511443China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Nonlinear Physics Centre Research School of PhysicsAustralian National UniversityCanberraACT 2601Australia Qingdao Innovation and Development Center of Harbin Engineering University Qingdao 266000China

Lanthanide-doped upconversion nanoparticles emerged recently as an attractive material platform underpinning a broad range of innovative applications such as optical cryptography,luminescent probes,and ***,the intricate 4f-associated electronic transition in upconversion nanoparticles leads only to a weak photoluminescence intensity and unpolarized emission,hindering many applications that demand ultrabright and polarized light ***,we present an effective strategy for achieving ultrabright and dual-band polarized upconversion *** employ resonant dielectric metasurfaces supporting high-quality resonant modes at dual upconversion bands enabling two-order-of-magnitude amplification of upconversion *** demonstrate that dual-band resonances can be selectively switched on polarization,endowing cross-polarization controlled upconversion luminescence with ultra-high degrees of polarization,reaching approximately 0.86 and 0.91 at dual emission wavelengths of 540 and 660 nm,*** strategy offers an effective approach for enhancing photon upconversion processes paving the way towards efficient low-threshold polarization upconversion lasers.

关键词： polarization polarized resonant

Comparative investigation of three types of ethanol sensor based on NiO-SnO_2 composite nanofibers

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

Chinese Science Bulletin 2012年第17期57卷 2087-2093页

作者： SHEN RenSheng li xiangping XIA XiaoChuan liANG HongWei WU GuoGuang liU Yang CHENG ChuanHui DU GuoTong School of Physics and Optoelectronic Technology Dalian University of Technology Dalian 116024China State Key Laboratory on Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

NiO-SnO2 composite nanofibers were synthesized via electrospinning techniques and characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron *** types of sensor were applied to investigate the sensing properties of these *** A were fabricated by mixing the nanofibers with deionized water,and then grinding and coating them on ceramic tubes to form indirect heated gas *** B(with an area of 600 μm×200 μm) were formed by spinning nanofibers on Si substrates with Pt signal electrodes and Pt *** C were fabricated by spinning nanofibers on plane ceramic substrates(with a large area of 13.4 mm×7 mm) with Ag-Pd signal electrodes *** operating temperatures of sensors A and B were controlled by adjusting heater currents,and the operating temperatures of sensors C were controlled by adjusting an external temperature control *** results show that sensors C possess the highest sensing properties,such as high response values(about 42 to 100 μL/L ethanol),quick response/recovery speeds(the response and recovery times were 4 and 7 s,respectively),and excellent *** phenomena were explained by the retained fiber morphology and suitable sensor *** presented results can provide some useful information for the design and optimization of one-dimensional nanomaterial-based gas sensors.

关键词：复合纳米纤维乙醇传感器 SnO2 类型 NIO 温度控制装置 X射线光电子能谱扫描电子显微镜

微量Sc对高强铸造Al-Zn-Mg-Cu合金组织和力学性能的影响

在线全文

学校读者我要写书评

暂无评论

轨道交通材料 2024年第5期3卷 20-24页

作者：许永祥龚家林张宝尧李向平马俊成中车戚墅堰机车车辆工艺研究所股份有限公司江苏常州213011

为了开发铸造用高强铝合金,通过金相显微镜、扫描电镜的观察以及拉伸试验机、布氏硬度计的检测,研究了微量Sc对Al-Zn-Mg-Cu合金显微组织和力学性能的影响。结果表明,Sc的添加能够显著细化晶粒并提高合金力学性能,铸态合金的抗拉强度由17... 详细信息

为了开发铸造用高强铝合金,通过金相显微镜、扫描电镜的观察以及拉伸试验机、布氏硬度计的检测,研究了微量Sc对Al-Zn-Mg-Cu合金显微组织和力学性能的影响。结果表明,Sc的添加能够显著细化晶粒并提高合金力学性能,铸态合金的抗拉强度由179.3 MPa提高至203 MPa;经热处理后,硬度提升明显,非平衡共晶相消失,且有Al7Cu2Fe相残留;含Sc合金的抗拉强度、屈服强度和伸长率分别为591.7 MPa、516.7 MPa和4.2%,分别提高了22%、14.1%和320%。

关键词：微量Sc 高强铝合金细化晶粒显微组织力学性能

基于量子遗传算法的大规模风光并网发电系统储能优化方法

在线全文

学校读者我要写书评

暂无评论

自动化与仪器仪表 2024年第8期 207-211,218页

作者：张艳宋新甫李香平辛超山张艳来国网新疆电力有限公司乌鲁木齐830063 国网新疆电力有限公司经济技术研究院乌鲁木齐830002 天津天大求实电力新技术股份有限公司天津300392

大规模风光并网发电具有明显的间歇性、随机性,并且风能光能本身的发电特征又存在较大差异,配置储能是解决上述问题的有效方法。将不确定的风光出力场景转化为确定的、具有其典型特征的小规模场景集,基于该场景集为风光联合发电系统配... 详细信息

大规模风光并网发电具有明显的间歇性、随机性,并且风能光能本身的发电特征又存在较大差异,配置储能是解决上述问题的有效方法。将不确定的风光出力场景转化为确定的、具有其典型特征的小规模场景集,基于该场景集为风光联合发电系统配置储能,平抑新能源出力波动,提出一种基于量子遗传算法的大规模风光并网发电系统储能优化方法。在双向DC/DC变换器将储能系统与风光互补发电系统对接下,以蓄电池与对接系统后最充放电次数为目标函数生成稳定场景;以并网发电与储能的输出功率不允许超出最大功率为约束条件;采用量子遗传算法采集蓄电池荷电状态的反馈,通过量子位概率幅值对染色体编码,借助非门变异增加优化参数数量,利用旋转门法更新量子的相位,结合梯度函数、一阶差分找出稳定条件下的蓄电池输入功率,,完成稳定的储能容量调节。实验结果表明:所提方法的功率偏差值小,且能量缺失率也较低,故储能优化效果良好。

关键词：风光并网功率储能容量蓄电池充放电染色体量子遗传算法