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Methane hydrate crystal growth on shell substrate

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Chinese Journal of Chemical Engineering 2022年第3期35卷 50-61页

作者： Xin Jiang Baojiang Sun Zhiyuan Wang Wantian Zhou Jiakai Ji Litao Chen School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China Key Laboratory of Unconventional Oil and Gas Development China University of Petroleum(East China)Qingdao 266580China

Hydrate crystals growth on the surface of methane bubble(hydrate film)in pure water was studied by using a high-pressure visible microscope under the conditions of subcoolingΔT=5.44-13.72 K and methane concentration differenceΔC=2.92-8.19 mol·L^(-1).It was found the hydrate film is porous and the hydrate crystals grow towards the liquid phase on the film *** crystal morphology and growth rate are affected byΔT andΔ***ΔTcrystals,and the axial growth rate of the crystal gradually ***ΔT>8.82 K orΔC>4.12 mol·L^(-1),the hydrate crystals grow in dendritic shape,and the axial growth rate increases first and then *** perimeter and area of the growing hydrate crystals were measured,and the fractal dimension of hydrate crystal under differentΔC andΔT was *** results show that the fractal dimension of columnar hydrate crystal is greater than ***3.87 mol·L^(-1)crystal is greater than 4;The fractal dimension of dendritic hydrate crystal is less than ***ΔC>4.77 mol·L^(-1),ΔTcrystal is less than 2.

关键词： Methane Hydrate crystal growth Morphology Fractal dimension

Control of crystal growth to obtain needle-shaped violet phosphorus with excellent photocatalytic degradation performance

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Nano Research 2023年第2期16卷 3320-3325页

作者： Mengting Jin Yanhao Wang Mengyue Gu Xuewen Zhao Rongzheng Zhao Yuhao Zhang Yonghong Cheng Jinying Zhang School of Electrical Engineering Xi’an Jiaotong UniversityXi’an 710049China

The control of crystal growth is important but challenging for multi-disciplinary *** phosphorus,the most stable phosphorus allotrope,has recently been produced as a unique semiconducting layered *** crystal orientation and morphology bring extra performance due to its unique structure and ***,the layered violet phosphorus has been controlled to grow along the c-axis to give tunable length up to centimeters with the assistance of tin,while the reported flat bulk ones with thickness are limited to *** as-produced needle-shaped violet phosphorus has also been demonstrated to significantly enhance the photocatalytic degradation of methyl orange pollutants due to its special crystallographic *** 98.6%of methyl orange pollutants with a concentration of 50 ppm were degraded within 80 min under visible light conditions by needle-shaped violet phosphorus,which is much more effective than that of amorphous red phosphorus with only 14.1%degradation.

关键词： crystal growth photocatalytic degradation red phosphorus tin violet phosphorus

Single crystal growth and electrochemical studies of garnet-type fast Li-ion conductors

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Tungsten 2022年第4期4卷 263-268页

作者： Yi-Tian Wang Xi Chen Department of Electrical and Computer Engineering University of CaliforniaRiversideCA92521USA

All-solid-state batteries have attracted much attention due to their improved safety and higher energy density as compared to the conventional *** to the excellent chemical stability against lithium metal and relatively high ionic conductivity at room-temperature,garnet-type fast lithium ion conductors with three-dimensional lithium ion transport channels are promising solid electrolytes for all-solid-state *** order to better understand the intrinsic lithium-ion transport mechanisms and prevent lithium dendrite formation,it is desired to investigate single-crystal solid *** this perspective,we review several methods reported to grow single crystals of garnet-type *** and cons of different growth methods are ***,we introduce some case studies on electrochemical properties of garnet-type single *** addition,we provide some perspectives about potential research directions of single-crystal solid electrolytes for all-solid-state batteries.

关键词： Solid electrolyte Single crystal Garnet-type lithium-ion conductor All-solid-state battery crystal growth

crystal growth of CsB_3O_5 from NaF Flux

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Chinese Journal of Structural Chemistry 2007年第9期26卷 1047-1052页

作者：陈国军吴以成傅佩珍 Technical Institute of Physics and Chemistry Beijing Center for Crystal R&D The Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Beijing 100039 China

Nonlinear optical CsB3O5 single crystals have been grown successfully using NaF as a flux. The primary CsB3O5-NaF quasi-binary system has been investigated by X-ray diffraction and differential thermal analysis. There is a single eutectic point, and the eutectic composition corresponds to 40mol% NaF with the temperature of 690.5 ℃ in CsB3O5-NaF system. Volatility of the CsB3O5-NaF system along the liquidus has been measured, and the volatiles of the solution were collected and detected by XRD method. growth of CsB3O5 crystals was carried out by different composition of NaF in CsB3O5-NaF system, and the growth parameters were discussed. Simultaneously, the properties of grown crystals from NaF flux were characterized by transmission spectrum and scanning electron microscopy.

关键词： CsB3O5(CBO) crystal growth CsB3O5-NaF system X-ray diffraction

crystal growth,spectral properties and Judd-Ofelt analysis of Pr:CaF_(2)-YF_(3)

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Chinese Physics B 2021年第10期30卷 624-629页

作者： Jie Tian Xiao Cao Wudi Wang Jian Liu Jianshu Dong Donghua Hu Qingguo Wang Yanyan Xue Xiaodong Xu Jun Xu School of Physics Science and Engineering Institute for Advanced StudyTongji UniversityShanghai 200092China Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronic EngineeringJiangsu Normal UniversityXuzhou 221116China

The 0.6 at.%Pr^(3+)-doped CaF_(2)-YF_(3)crystal was successfully grown by the temperature gradient technique(TGT).X-ray diffraction analysis showed that the grown crystal still had cubic *** absorption spectrum,emission spectrum,Judd-Ofelt analysis and fluorescence decay curve at room temperature were *** fluorescence lifetime of Pr:CaF_(2)-YF_(3)crystal was 45.46µs,and theσem·τof ^(3)P0→^(3)H_(6) and ^(3)P0→^(3)F_(2) transitions were calculated to be 80.92×10^(−20) cm^(2)·µs and 388.7×10^(−20) cm^(2)·µs,*** FWHMs are 20.1 nm and 6.8 nm,which are higher than those of Pr:LiYF_(4),Pr:LiLuF_(4),Pr:LiGdF_(4) and Pr:BaY_(2)F_(8) *** results show that the Pr:CaF_(2)-YF_(3)crystal is expected to achieve 605 nm orange light and 642 nm red light laser operation.

关键词： CaF2-YF3 crystal growth spectral property Judd-Ofelt theory

crystal growth Kinetics of Nanocrystalline ZnS under Surface Adsorption

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Chinese Journal of Structural Chemistry 2007年第10期26卷 1145-1152页

作者：张静蓝尤钊陈达贵任国强 State Key Laboratory of Structural Chemistry and Laboratory of Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterNational Engineering Research Center for Optoelectronic Crystalline MaterialsThe Chinese Academy of Sciences College of Chemistry and Life Sciences Zhejiang Normal University

The crystal growth mechanism, kinetics, and microstructure development play a fundamental role in tailoring the materials with controllable size and morphology. In this study, by introducing the strong surface adsorption of the concentrated NaOH, two-stage crystal growth kinetics of ZnS nanoparficles was observed. In the first stage, the primary particles grow into a size over a hundred times of the original volume and the growth is controlled by the crystallographically specific oriented attachment. The first stage data were fitted by the ＂multistep OA kinetic model＂ built based on the molecular collision and reaction. In the second stage, following the dispersal of nanoparficles, an abrupt transition from asymptotic to parabola growth kinetics occurs, which can be fitted by a standard Ostwald ripening volume diffusion model. The presence of surface adsorption causes the two-stage growth kinetics and permits an almost exclusive OA-based growth to dominate in the first stage.

关键词： nanocrystalline ZnS crystal growth surface adsorption kinetics

crystal growth and spectral characterizations of Ho3+-doped Li3Ba2La3(MoO4)8 crystal

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Journal of Rare Earths 2017年第4期35卷 368-373页

作者：宋明君张娜娜孟庆国王林同李修芝王国富 School of Chemistry and Chemical EngineeringWeifang UniversityWeifang 261061China Fujian Institute of Researeh on the Structure of Matter The Chinese Academy of Sciences Fuzhou 350002China

A large Ho3＋：Li3Ba2La3（MoO4）8 crystal with high optical quality and well-developed appearance was grown by the flux method. The main spectral properties of the crystal, including the absorption spectra, fluorescence spectra and fluorescence decay curves were recorded at room temperature. The Judd-Ofelt （J-O） theory was applied to calculate the oscillator strength parameters Ω2, （t=2, 4, 6）, spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes of Ho3＋ ions undergoing transi- tions from ground state 5I8 to the excited states. The stimulated emission cross-section for the 517→5ls transition was estimated to be 1.32× 10-20 cm2 at 2045 nm by Fuchtbauer-Ladenburg （F-L） equation and the quantum efficiency of the 5I7 level was calculated to be 89%.

关键词： crystal growth optical properties Judd-Ofelt theory rare earths

High quality crystal growth and characterization of ferroelectric Ba_(0.77)Ca_(0.23)TiO_(3) single crystal

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Journal of Advanced Dielectrics 2023年第2期13卷 32-37页

作者： Lei Liu Fangyi Yin Guiyuan Zhao Limei Zheng Xiuwei Fu Zhitai Jia Xutang Tao State Key Laboratory of crystal Materials Shandong University JinanShandong 250100P.R.China School of Physics Shandong UniversityJinanShandong 250100P.R.China Shandong Research Institute of Industrial Technology Jinan Shandong 250100P.R.China

Ba_(0.77)Ca_(0.23)TiO_(3)(BCT)single crystal has been widely studied as a promising lead-free ferroelectric *** this work,high-quality BCT crystal was successfully grown by the Czochralski(CZ)*** as-grown crystal is crack-free and shows black *** possesses a high dielectric stability over a wide temperature range,while the dielectric loss is rather small below 90℃.Furthermore,it possesses excellent ferroelectric properties with residual polarization strength(Pr)and coercive field(Ec)of 17.93μC/cm^(2) and 8.47 kV/cm,***,BCT crystal shows large electromechanical coupling factors,with kt,k31,k33 and k15 of 0.535,0.254,0.714 and 0.721,*** piezoelectric coefficients d31,d33 and d15 are measured to be−36.5,130 and 246 pC/N,respectively.

关键词： Lead-free piezoelectric material oxides crystal growth Czochralski method

crystal growth, structure and properties of bismuth triborate BiB_3O_6 crystal

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Science China(Technological Sciences) 2002年第1期45卷 19-26页

作者：滕冰王继扬王正平江怀东刘宏胡小波董胜明刘跃岗邵宗书 State Key Lab of crystal Materials Shandong University Ji’ nan China

BiB3O6 (BIBO) single crystals with size of 46×23×10 mm3 and weight of 26.0 g have been successfully grown by top-seeded method. Problems encountered in the growth process of this crystal have been discussed in detail, and the methods of growing high-quality large crystals have been put forward. The relationship between their structure and properties is studied. The space group of monoclinic BiB3O6 is C2 and the cell parameters are a=7.1203(7) ?, b=4.9948(7) ?, c=6.5077(7) ?, β=105.586(8)″, and V=222.93(5) ?3. The density of BIBO is 4.8965 g/cm3. The Mohs’s scale of hardness is 5.5–6. There is no cleavage face in the crystal. The transmittance of BIBO is about 80 percent in the range from visible coherent light to near-infrared light. The ultraviolet cutoff wavelength is at 276 nm. BiB3O6 is a biaxial crystal and has two sets of axes, and the relative orientation of (X, Y, Z) with regard to (a, b, c) is: X//b, (Y, c)=47.2°, (Z, a)=31.6°, determined by X-ray analysis combined with polarized microscopy. Second-harmonic-generation (SHG) experiments were carried out for the first time. In type I phase-matching (PM) directions (11.1°, 90°) and (168.9°, 90°), SHG conversion efficiencies of two directions for 1.064 μm light are up to 67.7% and 58%, respectively. We have also obtained the third-harmonic-generation (THG) of 1.064 μm. The comparative experiments between BIBO and KTP were carried out on conversion efficiency, transmittance and hardness. All the above results indicate that BiB3O6 is a kind of excellent nonlinear optical (NLO) crystal.

关键词： BiB3O6 crystal growth crystal structure transmittance SHG