检索结果-南通市图书馆

SnIP-type atomic-scale inorganic double-helix semiconductors: Synthesis, properties, and applications

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3期17卷 2111-2128页

作者： Mudussar Ali Bowen Zhang Muhammad Khurram Qingfeng Yan engineering research center of Advanced rare earth materials(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084China

Flexible inorganic double helical semiconductors similar to DNA have fueled the demand for efficient materials with innovative structures and excellent properties.The recent discovery of tin phosphide iodide(SnIP),the first carbon-free double helical semiconductor at an atomic level,has opened new avenues of research for semiconducting devices such as thermoelectric and sensor devices,solar cells,and photocatalysis.It has drawn significant academic attention due to its high structural flexibility,band gap in the visible spectrum range,and non-toxic elements.Herein,the recent progress in developing SnIP,including its prestigious structure,versatile and intriguing properties,and synthesis,is summarized.Other analogues of SnIP and SnIP-based hybrid materials and their applications in photocatalysis are also discussed.Finally,the review concludes with a critical summary and future aspects of this new inorganic semiconductor.

关键词： tin phosphide iodide(SnIP) inorganic semiconductor inorganic double helix SnIP-based hybrids photocatalysis flexible material

Effect of grain size on thermal stability and oxygen storage capacity of Ce_(0.17)Zr_(0.73)La_(0.02)Nd_(0.04)Y_(0.04)O_2 solid solutions

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

Journal of rare earths 2019年第2期37卷 178-184页

作者： Yuhui Zhang Meisheng Cui Yongke Hou Xiaowei Huang Yongqi Zhang Qiannan Xue National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced materials Co.Ltd.

Nanostructured CeO_2-ZrO_2 materials are an irreplaceable constituent in catalytic systems for automobile exhaust purification due to their unique oxygen storage capacity(OSC). However, traditional CeO_2-ZrO_2 materials are easy to sinter at high temperature, which causes a sharp decrease of OSC. In this paper,La^(3+) , Nd^(3+) and Y^(3+) are chosen as dopants for CeO_2-ZrO_2 to improve anti-sintering and OSC properties.The Ce_(0.17) Zr_(0.73) La_(0.02) Nd_(0.04) Y_(0.04) O_2 powders(CZLNY) were prepared by co-precipitation method. The effects of grain sizes with different mixed chlorinated solution concentrations on performances were investigated. X-ray diffraction(XRD) and transmission electron micrograph(TEM) were performed to calculate the grain sizes of CZLNY. The specific surfaces, OSC and redox properties were investigated by N_2 adsorption/desorption and temperature programmed reduction(H2-TPR). The results show that introducing La^(3+) , Nd^(3+) and Y^(3+) into CeO_2-ZrO_2 lattice can improve the stability of phase structure and anti-sintering ability. Moreover, low concentration of mixed chlorinated solution remarkably improves structural and textural properties of CZLNY. Relatively large fresh grain exhibits superior thermal stability and OSC under the condition of being calcined at 800℃ for 3 h. The specific surface and OSC are42.37 m^2/g and 333.13 mmol/g after calcining at 1000℃ for 10 h, respectively. This is owing to the low sintered driving force of large grain and long-range migration energy of large pores during the sintering process, which are beneficial to the stability of structure in CZLNY materials.

关键词： Grain size Thermal stability Oxygen storage capacity CeO2-ZrO2 rare earths

White-light emitting single-phase phosphor La_3Si_6N_(11):Dy^(3+),Tb^(3+):Color tunable emission, thermal stability and energy transfer process

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2019年第4期37卷 350-355页

作者： Yuanhong Liu Yuan Xue Ronghui Liu Mingyue Chen Guantong Chen Chunpei Yan Xia Zhang Yu'nan Zhou Wei Gao Xiaole Ma National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced materials Co.Ltd.

A novel white-light emitting single-phase phosphor La_3 Si_6 N_(11):Dy^(3+),exhibiting two emission peaks centering at 475 and 575 nm, was prepared via conventional solid-state reactions. The structure and morphology of La_3 Si_6 N_(11):Dy^(3+)/Tb^(3+) were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The emission colors can be tuned from white to yellow-green through increasing the Tb^(3+) concentration in La_3 Si_6 N_(11):Dy^(3+),Tb^(3+), The mechanism of energy transfer(ET) from Dy^(3+) to Tb^(3+) is confirmed according to the excitation,emission spectra and decay lifetimes curve. The temperaturedependent luminescence measurements of La_(2.83)Si_6 N_(11):0.1 Dy^(3+),0.07 Tb^(3+) were also performed, and a good thermal stability is shown, suggesting superior properties for the application as white lightemitting diodes(w-LEDs) phosphor.

关键词： Single-phase White emission Energy transfer rare earths

Magnetic properties optimization of nanocomposite Nd_9Fe_(85)B_6 magnets by controlling microstructure of as-quenched ribbons

在线全文

学校读者我要写书评

暂无评论

rare Metals 2014年第3期33卷 299-303页

作者： Yu-Chao Liu Hong-Wei Li Kuo-She Li Dun-Bo Yu Jin-Ling Jin Yang Luo Liang Sun Ning-Tao Quan National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals

To optimize the magnetic properties of nanocomposite Nd9Fe85B6 magnets, the as-quenched ribbons with different microstructures were prepared at six wheel velocities from 10 to 30 m s^-1through rapid quenching,followed by a series of annealing treatments at 550-800 °C for 5-10 min. It is found that both the large initial grains at low cooling rate and high content of amorphous phase at high cooling rate cause a-Fe grains coarsening, which leads to a decline in the strength of exchange coupling interaction and the deterioration of magnetic properties. In order to optimize the magnetic properties, the as-quenched ribbons should be chosen with relatively small initial grains as well as a small amount of amorphous phase. For nanocomposite Nd9Fe85B6 materials, the optimized magnetic properties of Hcj= 446 kA m^-1, Br= 0.86 T,（BH）max=80 kJ m^-3are obtained for ribbons prepared at 18 m s-1after annealing at 620 °C for 5 min.

关键词： Nanocomposite Rapid quenching Microstructure Grain sizes

Phase forming law and electrochemical properties of A2B7-type La-Y-Ni-based hydrogen storage alloys with different La/Y ratios

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2023年第2期41卷 268-276页

作者： Jiaxuan Li Xiangyang He Wei Xiong Li Wang Baoquan Li Jin Li Shujuan Zhou Huizhong Yan State Key Laboratory of Baiyunobo rare earth Resource researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030China School of Chemistry and Chemical engineering Inner Mongolia UniversityHohhot 010021China national engineering research center of rare earth Metallurgy and Functional materials Baotou 014030China

The effects of different proportions of La and Y elements in the A-side on the structure and properties of A_(2)B_(7)-type La-Y-Ni hydrogen storage alloys were investigated.The(La,Y)_(2)Ni_(7)hydrogen storage alloys with different La/Y ratios were prepared by sintering the Y_(2)Ni_(4)precursor and different AB_(5)-type precursors at 1298 K for 5 h and subsequently annealed for 20 h at 1248 K.All the alloys only contain Ce_(2)Ni_(7)(2H-type)and Gd_(2)Co_(7)(3R-type)phases with different mass ratios.As the La/Y ratio decreases,the cell volume of the two phases declines and the corresponding plateau pressure gradually increases.As the proportion of Y in the alloy increases,the hydrogen storage capacity increases gradually from 1.309 wt%(La/Y=1/1)to 1.713 wt%(La/Y=1/5)and the high-rate discharge(HRD1500)ability of the alloy electrodes increases gradually from 62.7%(La/Y=1/1)to 88.6%(La/Y=1/5).The hydrogen diffusion rate in the bulk of the alloy is the controlling step of hydriding/dehydriding kinetics.The Y ele ment can effectively inhibit the hydrogen-induced amorphous(HIA)of La-Y-Ni alloys,but the poor stability of the Y element in alkaline KOH aqueous solution leads to a decrease in the electrochemical cyclic stability with increasing Y content.

关键词： La-Y-Ni hydrogen storage alloy A_(2)B_(7)-type structure La/Y ratio Hydrogenation characteristics rare earths

Grain boundary segregation and its influences on ionic conduction properties of scandia doped zirconia electrolytes

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2019年第6期37卷 645-651页

作者： Qiannan Xue Xiaowei Huang Jianxing Zhang He Zhang Zongyu Feng National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced materials Co. Ltd.

Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceria and scandia co-doped zirconia electrolytes sintered from 1300 to 1550 ℃ were chosen as research objects. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were performed to characterize the ceramic samples. The effects of grain size and grain boundary element segregation on the electrical conductivity were focused. Electrochemical impedance spectroscopy was used to calculate the bulk, grain boundary and specific grain boundary conductivity. Results show that the bulk and grain boundary ionic conductivity increases with the increasing grain size.However, the specific grain boundary conductivity decreases with the increasing grain size. This is explained by the fact that Sc^(3+) is segregated at the grain boundary, which leads to higher oxygen vacancy concentration when sintered at lower temperature.

关键词： Electrolytes Co-doped zirconia Grain size Dopant segregation Ionic conductivity rare earths

Effects of precursor moisture and inert N_2 atmosphere calcinations on structure and properties of alumina modified CeZrLaNd mixed oxides

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2019年第6期37卷 609-616页

作者： Meisheng Cui Zhizhe Zhai Hao Wang Yongke Hou Yongqi Zhang Xiaowei Huang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced materials Co. Ltd.

CeO_2-ZrO_2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of cerium zirconium mixed oxides are the key properties for the automotive catalysts so as to meet the strict emission regulations. In this work, alumina modified CeZrLaNd mixed oxides were prepared by a co-precipitation method. The effects of moisture in precursor and inert N2 atmosphere during calcinations on the structure and properties were investigated by Brunauer-Emmett-Teller(BET) surface area measurements, X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), hydrogen temperature-programmed reduction(H_2-TPR), oxygen storage capacity(OSC), Raman spectroscopy, and X-ray photoelectron spectroscopy(XPS). The results show that the moisture in precursor during calcinations increases the crystal grain size of the cerium zirconium mixed oxides, improving the thermal stability. And the aged surface area of sample after being calcined at1000 ℃ for 4 h reaches 68.8 m^2/g(5.7% increase compared with the common sample). The inert N2 atmosphere endows a great pore-enlarging effect, which leads to high fresh surface area of 148.9 m2/g(13.5% increase compared with the common sample) and big pore volume of 0.5705 mL/g. The redox and oxygen storage capacity are also improved by inert N2 atmosphere with high OSC value of 241.06μmolO_2/g(41.3% increase compared with the common calcination), due to the abundant formation of the crystal defects and oxygen vacancies.

关键词： Precursor moisture Inert N2 atmosphere Calcinations Alumina modified CeZrLaNd mixed oxides rare earths

A comparison research on replacements of Ba^(2+)by Lu^(3+)and Ba^(2+)-Si^(4+)by Lu^(3+)-Al^(3+)in BaSi_(2)O_(2)N_(2):Eu phosphors

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2022年第1期40卷 20-28页

作者： Di Wu Lili Liu Huangbin Duan Junrong Wang Wanfang Zou Jiaqing Peng Xinyu Ye Faculty of materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyCanzhou 341000China national engineering research center for Ionic rare earth Ganzhou 341000China Key Laboratory of rare earth Luminescence materials and Devices of Jiangxi Province Ganzhou 341000China Jiangxi rare earth Functional materials Technology Co. Ltd.Ganzhou 341000.China

As a cyan-emitting oxonitridosilicate phosphor,BaSi_(2)O_(2)N_(2):Eu^(2+)can be used as a competent cyan compensator to improve the color rendering index of white light-emitting diodes(WLEDs).However,low luminescence efficiency and poor thermal stability of this type of phosphor seriously suppress its actual application in full-spectrum lighting.The replacements of Ba^(2+)by Lu^(3+)and Ba^(2+)-Si^(4+)by Lu^(3+)-Al^(3+)can greatly increase the luminescence intensity and improve the thermal stability at the same time.With Lu^(3+)doping,the internal quantum efficiencyηIQE Ba_(0.925)Si_(2)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+)is 24.08%higher than that of Ba_(0.97)Si_(2)O_(2)N_(2):0.03 Eu^(2+).After Al^(3+)co-doping,theηIQE is further increased by 10.31%compared to Ba_(0.925)Si_(2)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+).When the temperature rises to 473 K,the luminescence intensity of Ba_(0.925)Si_(2)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+)maintains 62.32%of that at room temperature,which increases by 17.35%in relative to the Ba_(0.97)Si_(2)O_(2)N_(2):0.03 Eu^(2+),while the luminescence intensity of Ba_(0.925)Si_(1.97)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+),0.03 Al^(3+)keeps 73.87%of the initial value,which increases by18.52%compared to Ba_(0.925)Si_(2)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+).The mechanisms for luminescence and thermal stability improvement are proposed.The Ba_(0.925)Si_(1.97)O_(2)N_(2):0.03 Eu^(2+),0.045 Lu^(3+),0.03 Al^(3+)cyan phosphor,Y3 Al5 O12:Ce3+yellow phosphor and CaAlSiN3:Eu^(2+)red phosphor are mixed thoroughly and coated on a blue LED(450 nm)to assemble a WLED.The WLED demonstrates a color rendering index(Ra)of 97.1 at150 mA,and the R1-R15 values are all above 90.The results indicate that as an effective cyan compensator in WLED,the BaSi_(2)O_(2)N_(2):Eu^(2+),Lu^(3+),Al^(3+)phosphor has great application prospect in the field of full-spectrum lighting.

关键词： Full-spectrum lighting BaSi_(2)O_(2)N_(2) Luminescence efficiency Thermal stability rare earths

Luminescent properties of Ce^(3+),Er^(3+) co-doped La_3Si_6N_(11)

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2019年第3期37卷 248-252页

作者： Yuan Xue Ronghui Liu Yuanhong Liu Huibing Xu Guantong Chen Xia Zhang Wei Gao Ze Jiang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced materials Co. Ltd.

In order to obtain near-infrared phosphor pumped by blue chip with high luminous efficiency, a novel near-infrared phosphor Ce^(3+)/Er^(3+) doped La_3Si_6N_(11) was designed and firstly prepared via conventional solid-state reactions. The structure and morphology of Ce^(3+)/Er^(3+) doped La_3Si_6N_(11) were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). Compared with Er^(3+) doped La_3Si_6N_(11),the emission intensity of the Ce^(3+), Er^(3+) co-doped phosphor can be increased more than 5 times.Meanwhile, the mechanism of energy transfer from Ce^(3+) to Er^(3+) is confirmed according to the excitation,emission spectra and decay lifetimes curve. Above results suggest that La_3 Si_6 N_(11):Ce^(3+),Er^(3+) is a promising near-infrared phosphor for blue pumped LEDs(light-emitting diodes).

关键词： Solid state reaction Energy transfer Near-infrared phosphor La3Si6N11:Ce3+ Er3+ rare earths