检索结果-南通市图书馆

2 μm mid-infrared optical spectra of Tm3+-doped germanium gallate glasses

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2009年第5期27卷 781-785页

作者： XIA Haiping LIN Qiongfei zhang jianli zhang Qinyuan Laboratory of Photo-electronic Materials Ningbo University Ningbo 315211 China Laboratory of Photo-electronic Materials Ningbo University Ningbo 315211 China Laboratory of Photo-electronic Materials Ningbo University Ningbo 315211 China Key Laboratory of Specially Functional Materials of Ministry of Education and Institute of Optical Communication Materials South China University of Technology Guangzhou 510641 China

Glasses with the composition of 65GeO212Ga2O3-10BaO-8Li2O-5La2O3(molar ratio) doped with 1.526 wt.%, 3.006 wt.%, 5.836 wt.%, 11.028 wt.%, and 15.678 wt.% Tm2O3, respectively, were fabricated by conventional melting method. According to the absorption spectra and the Judd-Ofelt theory, the J-O strength parameters (Ω2,Ω4, Ω6) were calculated, with which the radiative transition probabilities,branching ratios and radiative lifetimes were obtained. The infrared emission spectra (with 808 nm LD excitation) at～1.47 and～1.8 μm of various concentrations of Tm3+-doped glasses were studied. The emission intensity at～1.8 μm reached to the maximum when the Tm2O3-doping concentration was near to be～3.006 wt.% (1.0 mol.%), and then decreased as doping concentration increased further. The mechanism of the fluorescence intensity change was explained with the cross-relaxation effect and the concentration quenching effect of Tm3+. Meanwhile, according to McCumber theory, the absorption and emission cross-sections corresponding to the 3F4→3H6 transitions of Tm3+ at 1.8 μm was obtained. For Tm3+-doped germanate glasses, the maximum emission cross-section reached a value higher than that re-ported for fluorozircoaluminate glasses. It is expected to be a favorable candidate host for～2.0 μm mid-inflated laser because the glass shows favorable optical spectra.

关键词： Tm3+-doped germanium-gallate glasses spectral properties cross relaxation emission cross-section rare earths

Optical spectroscopy and crystal-field strength of Cr^(3+) in various solid matrixes

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第1期25卷 51-57页

作者： XIA Haiping WANG Jinhao WANG Hongyin zhang jianli zhang Yuepin XU Tiefeng The Laboratory of Photo-electronic Materials Ningbo University Ningbo 315211 China

The Cr^3＋：BeAl2O4 crystal, Cr^3＋：LiNbO3 crystal, and ZnO-Al2O3-SiO2 glass-ceramic were obtained by the Czochralski technique, Bridgman method, and melting processing, respectively. The optical absorption and emission spectra of the above Cr^3＋-incorporated solid-state materials were recorded. The technical parameters for growing high-quality Cr^3＋：BeAl2O4 and Cr^3＋：LINbO3 crystals were obtained. The results indicate that the optical absorption and fluorescence spectra of Cr^3＋ show quite a few differences in various matrixes. The sharp line emissions were observed in the Cr^3＋：BeAl2O4 and Cr^3＋：LiNbO3 crystals. The crystal-field parameters （Dq） for Cr^3＋. in different matrixes were calculated from their corresponding spectra. It is indicated that Cr^3＋：BeAl2O4 and Cr^3＋：LiNbO3 belong to the high-field site crystal, while the Cr^3＋ ZnO-Al2O3-SiO2 glass and glass-ceramic belong to the weak-field site crystal.

关键词： special functional inorganic materials optical spectroscopy optical measurement Cr^3+ ion matrix

Photoluminescence properties of Tm^(3+)/Tb^(3+)/Sm^(3+) tri-doped Na_(5)Y_(9)F_(32) single crystal with high thermal stability for white light-emitting diodes

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2021年第5期39卷 512-519页

作者： Yang Qiao Xiong Zhou jianli zhang Haiping Xia Hongwei Song Baojiu Chen Key Laboratory of Photo-electronic Materials Ningbo UniversityNingbo 315211China State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering and College of PhysicsJilin UniversityChangchun 130012China Department of Physics Dalian Maritime UniversityDalian 116026China

A novel Tm^(3+)/Tb^(3+)/Sm^(3+)tri-doped Na_(5)Y_(9)F_(32)single crystal was synthesized by a modified Bridgman method for the propose of white light emitting *** fluorescence spectra of various Sm^(3+)ion concentrations and fixed 0.4 mol%Tm^(3+)and 0.5 mol%Tb^(3+)were measured and studied systematically excited by near-ultraviolet light of 355 *** Sm3+ion concentration takes apparent effect on the relative intensity of peaks in the visible region and the color coordinate combining from these emission bands.A near pure white light emission with color coordinates(0.3295,0.3057)and color temperature(5657 K)can be obtained when the concentrations of Tm^(3+),Tb^(3+)and Sm^(3+)ions are 0.4 mol%,0.5 mol%and 0.8 mol%,***,the practical down-conversion internal quantum yield was measured by integrating spheres at about 14.39%.The tri-doped Na_(5)Y_(9)F_(32)single crystal shows a high thermal stability inferring from the temperature dependent emission in which the integrated emission intensities are reduced only by^3%with the increase of temperature from 280 to 450 *** present results demonstrate that the Tm^(3+)/Tb^(3+)/Sm^(3+)tri-doped Na_(5)Y_(9)F_(32)single crystal may provide a promising candidate for white light-emitting diodes,luminescent materials and fluorescent display devices.

关键词： Na_(5)Y_(9)F_(32)single crystal Tm^(3+)/Tb^(3+)/Sm^(3+) Bridgman method White light emission Rare earths

Sea-level variation/change and thermal contribution in the Bering Sea

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2005年第6期24卷 36-45页

作者： ZUO Juncheng zhang jianli DU Ling LI Peiliang LI Lei College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China College of Physical and Environmental Oceanography Ocean University of China Qingdao 266003 China

The long-term sea-level trend in the Bering Sea is obtained by the analysisof TOPEX/Poseidon altimeter data, including the data of two tide gauges. The averaged sea-level inthe Bering Sea rises at a rate of 2.47 mm/a from 1992 to 2002. The mean sea-level is falling in themost part of the Bering Sea, especially in its central basin, and it is rising in the northeasternpart of the Bering Sea. During the 1998/99 change, the sea-level anomaly differences exhibit asignificant sea-level anomaly fall in the deep basin of the Bering Sea, which is roughly in the sameposition where a prominent SST fall exists. The maximal fall of sea-level is about 10 cm in thesouthwestern part of the Bering Sea, and the maximal fall of about 2℃ in the SST also appeared inthe same region as the sea level did. The steric sea-level change due to temperature variations isdiscussed. The results are compared with the TOPEX/Poseidon altimeter data at the different spatialscales. It is indicated that the seasonal amplitude of the steric height is about 35% of theobserved TOPEX/Poseidon amplitude, which is much smaller than the 83% in the mid-latitudes area. Thesystematic difference between the TOPEX/Poseidon data with the range of about 7.5 cm and thethermal contribution with the range of about 2.5 cm is about 5 cm. This indicates that the thermaleffect on the sea level is not as important as the case in the mid-latitudes area. In the BeringSea, the phase of the steric height leads the observed sea level by about three months.

关键词： sea-level variation steric bering sea

Effect of preparation methods on the structure and catalytic performance of Fe–Zn/K catalysts for CO2 hydrogenation to light olefins

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第4期26卷 761-767页

作者： Xu Wang jianli zhang Jingyu Chen Qingxiang Ma Subing Fan Tiansheng Zhao State Key Laboratory of High-effidency Utilization of Coal and Green Chemical Engineering College of Chemistry & Chemical Engineering Ningxia University Yinchuan 750021 China

Potassium promoted iron–zinc catalysts prepared by co-precipitation method(C–Fe–Zn/K),solvothermal method(S–Fe–Zn/K)and hydrothermal method(H–Fe–Zn/K)could selectively convert CO_2to light olefins,*** physicochemical properties of the obtained catalysts were determined by SEM,N_2physisorption,XRD,H_2-TPR,CO_2-TPD and XPS *** results demonstrated that preparation methods had great influences on the morphology,phase structures,reduction and adsorption behavior,and hence the catalytic performance of the *** samples prepared by hydrothermal and co-precipitation method generated small uniform particles and led to lower specific surface *** contrast,microspheres with larger specific surface area were formed by self-assembly of nanosheets using solvothermal ***_2O_4was the only detectable phase in the fresh C–2Fe–1Zn/K,S–3Fe–1Zn/K and S–2Fe–1Zn/K ***_2O_4and ZnO co-existed with increasing Zncontent in S–1Fe–1Zn/K sample,while ZnO and Fe_2O_3could be observed over H–2Fe–1Zn/K *** the used samples contained Fe_3O_4,ZnO and Fe_5C_*** peak intensity of ZnO was strong in the AR-H–2Fe–1Zn/K sample while it was the lowest in the AR-C–2Fe–1Zn/K sample after *** formation of ZnFe_2O_4increased the interaction between iron and zinc for C–2Fe–1Zn/K and S–Fe–Zn/K samples,causing easier reduction of Fe_2O_3to Fe_3O_*** surface basicity of the sample prepared by co-precipitation method was much more than that of the other two *** CO_2hydrogenation,all the catalysts showed good activity and olefin *** CO selectivity was increased with increasing Zncontent over S–Fe–Zn/K samples.H–2Fe–1Zn/K catalyst preferred to the production of C_5^+***_2conversion of 54.76%and C_2~=–C_4~=contents of 57.38%were obtained on C–2Fe–1Zn/K sample,respectively.

关键词： CO2 hydrogenation Light olefins Preparation methods Iron–zinc catalyst

Fluorescence Properties of Eu^(3+) Doped in Na_5Lu_9F_(32) Single Crystals

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2019年第2期34卷 317-323页

作者：王珲夏海平 SHI Xudong CHENG Guanghai zhang jianli Key Laboratory of Photoelectronic Materials Ningbo University

Eu^(3+) ion doped cubic Na_5Lu_9F_(32) single crystals with high quality were synthesized by a modified Bridgman method by using a high 70-90 ℃/cm temperature gradient for cross solid-liquid interface. The optical spectroscopic investigations of the obtained single crystal were reported for the absorption, excitation and emission. The experimental results show that a strong red emission at 609 nm attributing to the ~5D_0→~7F_2 transition of Eu^(3+) doped Na_5Lu_9F_(32) single crystals can be obtained under the excitation of 394 nm light and reach the maximum when the Eu^(3+) doping concentration is 4 mol% in present research. The local covalent is enhanced and symmetry is reduced with the increase of Eu^(3+) concentrations inferring from the strength parameters Ω_2 and Ω_4 calculated by their measured emission spectra. The CIE chromaticity coordinates of the 4 mol% Eu^(3+) doped Na_5Lu_9F_(32) single crystals are calculated as(x=0.626, y=0.3736), which are close to the NTSC standard values for red(x=0.67, y=0.33). The experimental results reveal that the single crystal can be used as potential red phosphors under near ultraviolet(NUV) light excitation.

关键词： optical materials crystal growth red phosphors rare earth

Effect of annealing atmosphere on magnetic properties of pure ZnO and Na:ZnO films

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2012年第1期31卷 27-30页

作者： Wu, Kai Xu, Xiaoguang Yang, Hailing zhang, jianli Miao, Jun Jiang, Yong State Key Laboratory for Advanced Metals and Materials School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Pure ZnO and Zn0.96Na0.04O films were grown on quartz substrates by sol-gel *** XRD analysis revealed that all thin films had hexagonal wurtzite structure and obvious c-axis preferred *** was precisely measured by an alternating gradient magnetometer (AGM).To explore the nature original ferromagnetism,the effect of annealing atmosphere on magnetic properties of the films was *** with pure ZnO,magnetic hysteresis loops showed that doping Na atoms enhanced saturation *** mag-netism of the films annealed in the air atmosphere was significantly better than that in the O2 *** photoluminescence (PL) spec-trum analysis suggested that the ferromagnetism was due to the defects in the films.

关键词： pure ZnO Na-doped ZnO anneal sol-gel

Prediction of China's Submerged Coastal Areas by Sea Level Rise due to Climate Change

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2013年第3期12卷 327-334页

作者： ZUO Juncheng YANG Yiqiu zhang jianli CHEN Meixiang XU Qing Key Laboratory of Coastal Disaster and Defence Ministry of EducationHohai University National Marine Data and Information Service

Based on the simulation with the Ocean-Atmosphere Coupled Model CCSM and Ocean Model POP under the green- house gas emission scenario of the IPCC SRES A2 （IPCC, 2001）, and on the earth crust subsidence and glacier melting data, the relative sea level change is obtained along the coast of China in the 21 st century. Using the SRTM elevation data the submergence of coastal low land is calculated under the extreme water level with a 100-year retum period. The total flooding areas are 98.3× 10^3 and 104.9× 10^3 km2 for 2050 and 2080, respectively. For the three regions most vulnerable to extreme sea level rise, i.e., the coast of Bohai Bay, the Yangtze River Delta together with neighboring Jiangsu Province and northern Zhejiang Province, and the Pearl River Delta, the flooded areas are 5.0× 10^3, 64.1×10^3 and 15.3 × 10^3 km2 in 2050 and 5.2 × 10^3, 67.8×10^3 and 17.2 × 10^3 km2 in 2080, respectively.

关键词： sea level rise submerged area extreme water level of 100-year recurrence 1985 National Height Datum

Self-swelling derived frameworks with rigidity and flexibility enabling high-reversible silicon anodes

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第8期34卷 387-391页

作者： Peng Liu Bingqing Li jianli zhang Hongfu Jiang Zhong Su Chao Lai School of Chemistry and Materials Science Jiangsu Normal UniversityXuzhou 221116China Jiangsu Xinhua Semiconductor Material Technology Co. Ltd.Xuzhou 221116China

Silicon is recognized as the most advantageous next-generation anode material for LIBs in terms of its extremely high theoretical capacity and appropriate operating ***,the application of Si anode is limited by huge volume expansion emerging with cycling,which in turn induces the collapse of the electrode structure,resulting in rapid capacity ***,we report a strategy using self-swelling artificial laponite to prepare a laponite/MXene/CNT composite framework with both rigidity and flexibility,which can excellently address these challenges of Si *** self-swelling artificial laponite participates in the construction of hierarchical and porous structures,providing sufficient buffer space to mitigate the volume expansion of the LixSi alloying ***,tough and tightly cross-linked silicate nanosheets can improve the mechanical strength of the framework for strong structural *** importantly,the negative charge between the layers of artificial laponite can effectively promote fast Li-ion transport in the *** free-standing silicon anode enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs and a higher reversible capacity of 2381.8 mAh/g at 0.1 C after 50 cycles with an initial coulombic of 85.6%.This work provides a simple and practical fabrication strategy for developing high-performance Si-based batteries,which can speed up their commercialization.

关键词： Self-swelling derived framework High mass loading High areal capacity Si anodes Free-binder