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On the formation of Basu’s Type Ⅲ(peeled orange) gunshot residues 预览
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作者 Felice Nunziata Matteo Donghi 《Defence Technology(防务技术)》 CAS CSCD 2019年第1期23-26,共4页
In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by... In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by an outer lead leaflet.In this class of GSR particles the surface may show nodular structures of lead.Basu proposed an explanation in terms of a nucleus of antimony and barium that captures lead vapours produced after the explosion of a cartridge into a firearm:as solidification points of antimony and barium are close one another,both higher than solidification point of lead,he stated that lead occurs as a layer around the core in peeled orange GSR particles.In this paper we study the thermodynamic of the barium/antimony alloy and we hypothesize a formation process in terms of colloidal metal growth,charged particles and electrostatic attraction.We propose an updated model of formation for peeled orange GSR particles that explains the existence of outer lead leaflet and nodules in terms of electrostatic attraction of lead nanoparticles and instability of lead droplets. 展开更多
关键词 Peeled ORANGE PARTICLES GSR CDR CHARGED PARTICLES Electrostatic ATTRACTION Rayleigh DROPLET stability
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Tribo-charging of binary mixtures composed of coarse and fine particles in gas-solid pipe flow
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作者 Haifeng Wang Farzam Fotovat +1 位作者 Xiaotao T. Bi John R. Grace 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第2期101-109,共9页
Experiments were conducted to investigate the effect of adding fines on the tribo-charging of coarse glass beads. Four types of fines, i.e., copper, stainless steel, uncoated and silver-coated fine glass beads, mixed ... Experiments were conducted to investigate the effect of adding fines on the tribo-charging of coarse glass beads. Four types of fines, i.e., copper, stainless steel, uncoated and silver-coated fine glass beads, mixed w让h 240-830 μm glass beads were conveyed by air through a stainless-steel spiral pipe acting as a tribo-charger. Regardless of the type or electrical conductivity of the fine particles tested, adding small amounts of fines (up to 10wt%) to coarse glass beads resulted in a sharp increase in the mass and surface charge densities of the particles. In gen eral, the profiles of the mass and surface charge den sides of the fine-coarse particle mixtures as a function of the mixture composition were determined by the relative magnitude of contact potential differences and the total surface areas of all the comp on ents. The domi nant particle tri bo-electrification mecha nism switched from coarse particle-wall con tacts to fine particle-wall contacts when the fines weight percentage in the mixture exceeded 10%. A model was developed to predict the mass charge density of bi nary mixtures as a function of the mixture composition. 展开更多
关键词 Tribo-charging ELECTROSTATICS FINE particles BINARY MIXTURE GAS-SOLID flow
Localizing and Characterizing Colloidal Particles Scattering Using Lens-free Holographic Microscopy
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作者 华夏 杨程 +2 位作者 黄烨 闫锋 曹汛 《中国物理快报:英文版》 SCIE CAS CSCD 2019年第1期28-31,共4页
Lens-free holographic microscopy could achieve both improved resolution and field of view (FOV),which has huge potential applications in biomedicine,fluid mechanics and soft matter physics.Unfortunately,due to the lim... Lens-free holographic microscopy could achieve both improved resolution and field of view (FOV),which has huge potential applications in biomedicine,fluid mechanics and soft matter physics.Unfortunately,due to the limited sensor pixel size,target objects could not be located to a satisfactory level.Recent studies have shown that electromagnetic scattering can be fitted to digital holograms to obtain the 3D positions of isolated colloidal spheres with nanometer precision and millisecond temporal resolution.Here,we describe a lens-free holographic imaging technique that fits multi-sphere superposition scattering to digital holograms to obtain in situ particle position and model parameters:size and refractive index of colloidal spheres.We show that the proposed method can be utilized to analyze the location and character of colloidal particles under large FOV with high density. 展开更多
关键词 Lensless HOLOGRAPHIC MICROSCOPE COLLOIDAL particles BIOMEDICAL
Plasmonic resonant nonlinearity and synthetic optical properties in gold nanorod suspensions
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作者 HUIZHONG XU PEPITO ALVARO +4 位作者 YINXIAO XIANG TREVOR S.KELLY YU-XUAN REN CHENSONG ZHANG ZHIGANG CHEN 《光子学研究:英文版》 CSCD 2019年第1期28-35,共8页
We experimentally demonstrate self-trapping of light, as a result of plasmonic resonant optical nonlinearity,in both aqueous and organic(toluene) suspensions of gold nanorods. The threshold power for soliton formation... We experimentally demonstrate self-trapping of light, as a result of plasmonic resonant optical nonlinearity,in both aqueous and organic(toluene) suspensions of gold nanorods. The threshold power for soliton formation is greatly reduced in toluene as opposed to aqueous suspensions. It is well known that the optical gradient forces are optimized at off-resonance wavelengths at which suspended particles typically exhibit a strong positive(or negative) polarizability. However, surprisingly, as we tune the wavelength of the optical beam from a continuous-wave(CW) laser, we find that the threshold power is reduced by more than threefold at the plasmonic resonance frequency. By analyzing the optical forces and torque acting on the nanorods, we show theoretically that it is possible to align the nanorods inside a soliton waveguide channel into orthogonal orientations by using merely two different laser wavelengths. We perform a series of experiments to examine the transmission of the soliton-forming beam itself, as well as the polarization transmission spectrum of a low-power probe beam guided along the soliton channel. It is found that the expected synthetic anisotropic properties are too subtle to be clearly observed, in large part due to Brownian motion of the solvent molecules and a limited ordering region where the optical field from the self-trapped beam is strong enough to overcome thermodynamic fluctuations. The ability to achieve tunable nonlinearity and nanorod orientations in colloidal nanosuspensions with low-power CW laser beams may lead to interesting applications in all-optical switching and transparent display technologies. 展开更多
关键词 experimentally demonstrate greatly REDUCED suspended particles
Chemotherapy drugs derived nanoparticles encapsulating mRNA encoding tumor suppressor proteins to treat triple-negative breast cancer
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作者 Chengxiang Zhang Xinfu Zhang +9 位作者 Weiyu Zhao Chunxi Zeng Wenqing Li Bin Li Xiao Luo Junan Li Justin Jiang Binbin Deng David W. McComb Yizhou Dong 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第4期855-861,共7页
Triple-negative breast cancer(TNBC)is one type of the most aggressive breast can cers with poor prog no sis.It is of great urgency to develop new therapeutics for treati ng TNBC.Based on curre nt treatment guideline a... Triple-negative breast cancer(TNBC)is one type of the most aggressive breast can cers with poor prog no sis.It is of great urgency to develop new therapeutics for treati ng TNBC.Based on curre nt treatment guideline and genetic informatio n of TNBC,a combi nation al therapy platform in tegrati ng chemotherapy drugs and mRNA encoding tumor suppressor proteins may become an efficacious strategy.In this study,we developed paclitaxel amino lipid(PAL)derived nanoparticles(NPs)to incorporate both chemotherapy drugs and P53 mRNA.The PAL P53 mRNA NPs showed superior properties compared to Abraxane? and Lipusu? used in the clinic including high paclitaxel loading capacity(24 wt.%,calculated by paclitaxel in PAL),PAL encapsulation efficiency(94.7%±6.8%)and mRNA encapsulation efficiency(88.7%±0.7%).Meanwhile,these NPs displayed synergetic cytotoxicity of paclitaxel and P53 mRNA in cultured TNBC cells.More importantly,we demonstrated in vivo anti-tumor efficacy of PAL P53 mRNA NPs in an orthotopic TNBC mouse model.Overall,these chemotherapy drugs derived mRNA NPs provide a new platform to integrate chemotherapy and personalized medicine using tumor genetic information,and therefore represent a promising approach for TNBC treatment. 展开更多
关键词 clitaxel amino lipid DERIVED nano particles MRNA THERAPEUTICS combi NATION therapy triple- negative BREAST cancer
Astrophysical constraints on the proton-to-electron mass ratio with FAST
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作者 Xi Chen Simon P.Ellingsen Ying Mei 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2019年第2期15-24,共10页
That the laws of physics are the same at all times and places throughout the Universe is one of the basic assumptions of physics. Astronomical observations provide the only means to test this basic assumption on cosmo... That the laws of physics are the same at all times and places throughout the Universe is one of the basic assumptions of physics. Astronomical observations provide the only means to test this basic assumption on cosmological time and distance scales. The possibility of variations in the dimensionless physical constant μ-the proton-to-electron mass ratio, can be tested by comparing astronomical measurements of the rest frequency of certain spectral lines at radio wavelengths with laboratory determinations. Different types of molecular transitions have different dependencies on μ and so observations of two or more spectral lines towards the same astronomical source can be used to test whether there is any evidence for either temporal or spatial changes in the physical fundamental constants. μ will change if the relative strength of the strong nuclear force compared to the electromagnetic force varies. Theoretical studies have shown that the rotational transitions of some molecules which have transitions in the frequency range that will be covered by FAST(e.g., CH3 OH, OH and CH) are sensitive to changes in μ. A number of studies looking for possible variations in μ have been undertaken with existing telescopes, however, the greater sensitivity of FAST means it will open new opportunities to significantly improve upon measurements made to date.In this paper, we discuss which molecular transitions and sources(both in the Galaxy and external galaxies)are likely targets for providing improved constraints on μ with FAST. 展开更多
关键词 ISM:molecules radio lines:ISM techniques:radial VELOCITIES ELEMENTARY particles
3DPMD-Arc-based additive manufacturing with titanium powder as raw material 预览
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作者 Hoefer Kevin Mayr Peter 《中国焊接:英文版》 EI CAS 2019年第1期11-15,共5页
The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components with and without reinforcing particles in layer-by-layer design. Various demonstrators are prepared and analyzed. Th... The study aims to demonstrate the suitability of the 3DPMD for the production of titanium components with and without reinforcing particles in layer-by-layer design. Various demonstrators are prepared and analyzed. The microstructure, the porosity and the hardness values of the different structures are compared with each other through metallographic cross-sections. The uniform distribution of the carbides and the interaction with the matrix was analyzed by SEM and EDX.The miller-test method (ASTM G75-07) was used to determine data for the relative abrasivity of the structures. In summary, 3DPMD offers the possibility to produce titanium structures with and without reinforced particles. Using automated routines, it is possible to generate metal structures using welding robots directly from the CAD drawings. Microstructures and properties are directly related to the process and therefore material-process-property relationships are discussed within this work. 展开更多
关键词 ADDITIVE MANUFACTURING PLASMA TITANIUM 3D PLASMA metal DEPOSITION reinforced PARTICLES
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Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process
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作者 Meng Li Yangbo Tan +2 位作者 Jianglong Sun De Xie Zeng Liu 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期247-256,共10页
To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floati... To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds(Njd) of floating particles in transformative Kanbara Reactor(KR) are measured in one and four baffled stirred tanks experimentally. Then numerical simulations with standard k-ε model coupled with volume of fluid model(VOF) and discrete phase model(DPM) are conducted to analyze the flow field at the just drawdown speed Njd. The torques on the impeller obtained from experiments and simulations agree well with each other, which indicates the validity of our numerical simulations. Based on the simulations, three main drawdown mechanisms for floating particles, the axial circulation, turbulent fluctuation and largescale eddies, are analyzed. It’s found that the axial circulation dominates the drawdown process at small submergence(S = 1/4 T and 1/3 T) and the large-scale eddies play a major role at large submergence(S= 2/3 T and 3/4 T). Besides, the turbulent fluctuation affects the drawdown process significantly for up pumping mode at small submergence(S = 1/4 T and 1/3 T) and for down pumping mode at large submergence(S= 2/3 T and 3/4 T). This paper helps to provide a more comprehensive understanding of the KR desulphurizer drawdown process in the baffled stirred tank. 展开更多
关键词 LIGHT PARTICLES DRAWDOWN MECHANISM Baffled stirred tank SUBMERGENCE Numerical simulations KR impeller
颗粒间距及相对运动对轴承油膜压力的影响 预览
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作者 韩海燕 李娜娜 尚雪梅 《机械与电子》 2019年第3期27-29,共3页
针对滑动轴承润滑中润滑油含有固体颗粒的情况,将格子-波兹曼方法(LBM)应用到润滑问题的求解中,得到润滑油中含有固体颗粒时的油膜压力分布。并通过分析计算得出了颗粒间距及颗粒相对运动对轴承润滑的影响规律,使得轴承润滑分析更符合... 针对滑动轴承润滑中润滑油含有固体颗粒的情况,将格子-波兹曼方法(LBM)应用到润滑问题的求解中,得到润滑油中含有固体颗粒时的油膜压力分布。并通过分析计算得出了颗粒间距及颗粒相对运动对轴承润滑的影响规律,使得轴承润滑分析更符合实际工况。 展开更多
关键词 颗粒 格子波兹曼 润滑 轴承
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城市道路交叉口处颗粒物空间分布规律 预览
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作者 于泉 梁锐 +1 位作者 郭增增 朱小飞 《北京工业大学学报》 CAS CSCD 北大核心 2019年第5期485-492,共8页
为了在宏观上掌握交叉口处颗粒物的分布规律,通过采集北京市多个交叉口处的颗粒物质量浓度,并进一步分析颗粒物质量浓度与交通特性之间的相关关系以及数据之间的拟合估计,建立交叉口处颗粒物的空间扩散模型,最终得出颗粒物在城市道路交... 为了在宏观上掌握交叉口处颗粒物的分布规律,通过采集北京市多个交叉口处的颗粒物质量浓度,并进一步分析颗粒物质量浓度与交通特性之间的相关关系以及数据之间的拟合估计,建立交叉口处颗粒物的空间扩散模型,最终得出颗粒物在城市道路交叉口处的分布规律,即:颗粒物质量浓度在交叉口处横向断面上的分布基本呈现中央较高,随后向两侧递减的趋势;颗粒物在交叉口处50m范围内纵断面上的扩散规律为越靠近交叉口停车线的点位颗粒物质量浓度越高,波动越大,且人行道上的纵向分布波动性高于机动车道的波动性;颗粒物PM2.5与颗粒物PM10规律一致. 展开更多
关键词 交叉口 颗粒物 空间分布 扩散模型
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Improved thermal conductivity and dielectric properties of flexible PMIA composites with modified micro-and nano-sized hexagonal boron nitride
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作者 Cuangyu DUAN Yan WANG +2 位作者 Junrong YU Jing ZHU Zuming HU 《材料科学前沿:英文版》 SCIE CSCD 2019年第1期64-76,共13页
A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting tec... A series of flexible poly(m-phenylene isophthalamide)(PMIA)-based composites with different sizes and mass fractions of hexagonal boron nitride(hBN)were successfully manufactured for the first time via the casting technique.The effects of modified hBN particles on microstructure,mechanical properties,dielectric properties and thermal conductivities of fabricated composites were investigated.The results indicate that modified hBN particles manifest good compatibility with the PMIA matrix.The Young's modulus and Theat-resistance index of PMIA-based composites are increased with increasing the mass fraction of hBN particles.Due to additional thermal conductive paths and networks formed by nano-sized hBN particles,the K-m/n-hBN-30 composite displays the thermal conductivity of 0.94 W·m^-1·K^-1 higher than that of the K-m-hBN-30 composite(0.86 W·m^-1·K^-1),and more than 4 times higher than that of neat PMIA.Moreover,the obtained PMIA-based composites also show low dielectric constant and ideal dielectric loss.Owing to the excellent comprehensive performance,hBN/PMIA composites present potential applications in the broad field of electronic materials. 展开更多
关键词 poly(m-phenylene isophthalamide)(PMIA) thermal CONDUCTIVITY hBN PARTICLES DIELECTRIC property
超临界二氧化碳粒子射流破岩性能分析 预览
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作者 杜玉昆 陈晓红 +5 位作者 王瑞和 岳伟民 杜强 白殿刚 郝国亮 周艳 《中国石油大学学报:自然科学版》 EI CAS CSCD 北大核心 2019年第2期85-90,共6页
由于页岩和致密砂岩等非常规储层岩石的破岩门限压力大,为充分发挥超临界二氧化碳在开发非常规资源方面的技术优势,提出引入粒子后形成超临界二氧化碳粒子射流,提高射流的破岩效率。在优化超临界二氧化碳射流破岩实验流程的基础上,研制... 由于页岩和致密砂岩等非常规储层岩石的破岩门限压力大,为充分发挥超临界二氧化碳在开发非常规资源方面的技术优势,提出引入粒子后形成超临界二氧化碳粒子射流,提高射流的破岩效率。在优化超临界二氧化碳射流破岩实验流程的基础上,研制超临界二氧化碳粒子射流破岩实验装置,分析超临界二氧化碳粒子射流的破岩性能。结果表明:相对于纯超临界二氧化碳射流,加入石英砂30 s后超临界二氧化碳粒子射流的破岩性能得到大幅度增强,破岩体积提高了66.67%;超临界二氧化碳粒子射流的破岩性能随着喷嘴直径和喷距的增大先增强后减弱;本试验条件下最优喷嘴直径为3 mm、喷距为6 mm,粒径为0.3~0.5 mm;压力和温度越高,射流的破岩性能越强,但增强的趋势逐渐变缓。 展开更多
关键词 超临界二氧化碳 粒子 射流 破岩
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New Progress in Helicopter Rotor Wake Research 预览
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作者 XU Guohua SHI Yongjie ZHAO Qijun 《南京航空航天大学学报:英文版》 EI CSCD 2019年第1期36-56,共21页
Rotor wake analysis,a fundamental research of helicopter technology,has been widely applied for rotor aerodynamic analysis. This paper summarizes the research of different rotor wake models at home and abroad and revi... Rotor wake analysis,a fundamental research of helicopter technology,has been widely applied for rotor aerodynamic analysis. This paper summarizes the research of different rotor wake models at home and abroad and reviews the development process of rotor wake methods as well as the research achievement obtained in each stage. Then,the new progress of helicopter rotor wake methods is described in detail. It includes constant circulation contours modeling method of rotor wake,pseudo-implicit relaxation iteration and time-accurate solution method, research on aerodynamic interaction characteristics of helicopter rotor/fuselage by wake method,research on the rotor blade -vortex interaction noise and interaction of coaxial rigid rotor aerodynamics by viscous vortex particle method, and application of free wake method to helicopter flight dynamics modeling. In the end,some prospects for the research of helicopter rotor wake method are put forward,which clarifies the ideas for the future development of rotor wake method. 展开更多
关键词 HELICOPTER ROTOR free WAKE VISCOUS VORTEX particles aerodynamic characteristics FLIGHT dynamics WAKE progress
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Numerical simulation of particle formation and evolution in a vehicle exhaust plume using the bimodal Taylor expansion method of moments
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作者 Shuyuan Liu Tat Leung Chan Huijie Liu 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第2期46-55,共10页
The bimodal Taylor expa nsion method of moments (B-TEMOM) model scheme was developed to simulate the formation and evolution of vehicle exhaust particles. Two independent types of log-normal particle size distribution... The bimodal Taylor expa nsion method of moments (B-TEMOM) model scheme was developed to simulate the formation and evolution of vehicle exhaust particles. Two independent types of log-normal particle size distributions were selected in the B-TEMOM model scheme, comprising large and small particles to represent background (i.e., the surrounding environment) and vehicle exhaust particles, respectively. Concentration distributions of exhaust and background particles derived using this model scheme were verified against results from a moving secti onal method and the bimodal quadrature method of moments, showing excellent agreement. The effects of vehicle tailpipe ex 让 cond 让 ions (e.g., exhaust particle concentrations and velocity), sulfurcontent, and relative humidity on the evoluti on of particles were investigated numerically. Both two-dimensional and three-dimensional numerical simulations showed that tailpipe exit velocity and relative humid让y did not greatly affect the steady-state concentrations or the diameters of particles in urban atmospheres. Although an increase in sulfur content had little effect on the particle concentration, it led to background particles with larger geometric average diameter entering the environment. This coupled CFD-B-TEMOM numerical model provides a simple but accurate and efficient method for studying bimodal aerosol dynamics. 展开更多
关键词 VEHICLE exhaust particles BIMODAL Taylor expansi on method of MOMENTS Homogeneous NUCLEATION COAGULATION Tailpipe EXIT velocity Sulfur content and ambient relative humidity
Investigation of the performance of a pilot-scale barrel atmospheric plasma system for plasma activation of polymer particles 预览
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作者 Hisham M.Abourayana Peter J.Dobbyn +1 位作者 Pat Whyte Denis P.Dowling 《纳米技术与精密工程(英文)》 CAS CSCD 2019年第1期1-7,共7页
This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles.The polymer particles treated included acrylon... This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles.The polymer particles treated included acrylonitrile butadiene styrene(ABS)and polypropylene(PP).These particles had diameters in the range of 3–5mm.The initial studies were carried out using a laboratory-scale barrel reactor designed to treat polymer particle batch sizes of 20 g.A pilot-scale reactor that could treat 500 g particle batch sizes was then developed to facilitate pre-industrial-scale treatments.The effect of operating pulse density modulation(PDM)in the range 10%– 100%and plasma treatment time on the level of activation of the treated polymers were then investigated.ABS revealed a larger decrease inwater contact angle compared with PP after plasma treatment under the same conditions.The optimal treatment time of ABS(400 g of polymer particles)in the pilot-scale reactorwas 15 min.The plasma-activated polymer particles were used to fabricate dog-bone polymer parts through injection molding.Mechanical testing of the resulting dog-bone polymer parts revealed a 10.5%increase in tensile strength compared with those fabricated using non-activated polymer particles. 展开更多
关键词 Atmospheric pressure PLASMA BARREL PLASMA REACTOR Polymer particles Water contact angle X-ray PHOTOELECTRON spectroscopy Injection MOULDING
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CFD-DEM simulation of a pseudo-two-dimensional spouted bed comprising coarse particles
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作者 B. Mahmoodi S.H. Hosseini G. Ahmadi 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第2期171-180,共10页
In the present study, computational fluid dynamics (CFD) and the discrete element method (DEM) are used in conjunction with the Eulerian-Lagrangian method to simulate a pseudo-two-dimensional spouted bed comprising co... In the present study, computational fluid dynamics (CFD) and the discrete element method (DEM) are used in conjunction with the Eulerian-Lagrangian method to simulate a pseudo-two-dimensional spouted bed comprising coarse 6-mm particles. The open-source OpenFOAM code is used to solve the governing equations. The predicted vertical particle velocity along the bed axis, particle velocity profiles in the radial directi on, power spectral den sity, time-averaged particle velocity vectors, bed pressure drop, and solid flow pattern are evaluated and compared with existing experimental data. Good agreement is found between the CFD-DEM results and the measured data. It is also shown that the present CFD-DEM model accurately predicts the particle flow pattern throughout the bed. It is found that the drag force, solid stresses, and gravity play important roles in the CFD-DEM simulation of a spouted bed comprising coarse particles. 展开更多
关键词 CFD-DEM Pseudo-2D spouted BED HYDRODYNAMICS Coarse PARTICLES
微波法制备铜锌锡硫的研究进展 预览
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作者 沈韬 柴鲜花 +1 位作者 孙淑红 朱艳 《材料导报》 EI CAS CSCD 北大核心 2019年第13期2159-2166,共8页
尽管以铜铟镓硒(CIGS)和碲化镉(CdTe)为代表的第二代薄膜太阳能电池已成功实现商业化,截至目前,以CIGS为吸收层的电池的效率已经突破23%,但由于In元素稀缺,Cd元素有剧毒,限制了该电池的大规模生产。铜锌锡硫(Cu 2ZnSnS 4,CZTS)是一种直... 尽管以铜铟镓硒(CIGS)和碲化镉(CdTe)为代表的第二代薄膜太阳能电池已成功实现商业化,截至目前,以CIGS为吸收层的电池的效率已经突破23%,但由于In元素稀缺,Cd元素有剧毒,限制了该电池的大规模生产。铜锌锡硫(Cu 2ZnSnS 4,CZTS)是一种直接带隙半导体,因具有禁带宽度合适、光吸收系数高、组分无毒和储量丰富等优点,而成为目前太阳能电池中最具有潜力的吸收层材料之一。目前以CZTS为吸收层的太阳能电池的效率已突破12%,已接近于商业化的多晶硅太阳能电池的效率。目前,CZTS粉体的制备方法主要为以溶剂热法、一锅法和热注入法为代表的溶液法。由于这些方法需要昂贵的仪器设备、复杂的操作顺序、较长的反应时间,且易产生杂相,严重制约着生产效率的提高。微波法也是一种溶液化学反应法,由于具有反应速度快、操作简单、效率高、加热均匀、能够减小热梯度等优势,近年在太阳能电池材料制备领域引起了广泛关注。微波法制备CZTS薄膜通常有一步成膜和两步成膜两种途径。两步成膜法先通过微波合成CTZS的粉体,再将粉体分散之后通过旋涂等方法获得CZTS的薄膜。采用这种方法得到的薄膜更加均匀、致密、稳定。然而,CZTS属于四元化合物,化学计量比的少量偏离就很容易产生其他杂相,因此如何减少和控制杂相的生成,制备纯相、形貌可控的CZTS纳米晶体并将其应用于薄膜太阳能电池显得至关重要。最近几年,除了研究CZTS对器件性能的影响外,研究者们主要从选择合适的有机溶剂、原料配比、反应时间、反应温度及表面活性剂等制备工艺方面不断尝试,并取得了丰硕的成果,在充分发挥微波法反应速度快、操作简单、效率高、加热均匀优势的同时大幅提升了器件效率。目前,以微波法合成的CZTS为吸收层材料制备的太阳能电池的转换效率已从最初的0.25%� 展开更多
关键词 微波 Cu2ZnSnS4 粉体 薄膜
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钛柱撑蒙脱石颗粒的制备及其对镉离子的吸附 预览
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作者 宋祥 庹必阳 +2 位作者 赵徐霞 陈兵兵 龙文江 《功能材料》 EI CAS CSCD 北大核心 2019年第5期5099-5105,共7页
为脱除废水中镉离子,以钠基蒙脱石作基质材料,钛酸四丁酯为钛源,制备了钛柱撑蒙脱石。然后将聚乙烯醇、海藻酸钠、钛柱撑蒙脱石以一定的质量比制备钛柱撑蒙脱石颗粒,并进行颗粒的散失实验及镉离子的吸附实验,同时进行吸附等温线及吸附... 为脱除废水中镉离子,以钠基蒙脱石作基质材料,钛酸四丁酯为钛源,制备了钛柱撑蒙脱石。然后将聚乙烯醇、海藻酸钠、钛柱撑蒙脱石以一定的质量比制备钛柱撑蒙脱石颗粒,并进行颗粒的散失实验及镉离子的吸附实验,同时进行吸附等温线及吸附动力学研究。结果表明,Ti-MMT具有较大的晶面间距(d001=3.43nm)。当m(聚乙烯醇)∶m(海藻酸钠)∶m(钛柱撑蒙脱石)=0.6∶1.0∶20.0时,投加0.25g颗粒于pH值=6的100mg/L的镉离子废水中,在40℃下,吸附120min,颗粒对Cd^2+的吸附量达到7.89mg/g,去除率达到98.63%,且颗粒对Cd2+的吸附符合Langmuir等温线模型,吸附动力学符合拟二级动力学方程。 展开更多
关键词 钛柱撑蒙脱石 颗粒 吸附 镉离子
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Drying of pasty and granular materials in mechanically and conventional spouted beds
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作者 Robson C. Sousa Maria C. Ferreira +2 位作者 Haritz Altzibar Fábio B. Freire José T. Freire 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第1期176-183,共8页
A contactor vessel was built to operate as either a mechanically or a conventional spouted bed for the purpose of analyzing the drying of pasty and granular materials under comparable conditions in both configurations... A contactor vessel was built to operate as either a mechanically or a conventional spouted bed for the purpose of analyzing the drying of pasty and granular materials under comparable conditions in both configurations. A classical conical–cylindrical spouted bed with a 60° conical base and an air inlet central orifice was modified to enable the switch by introducing in the vessel’s center an open helicoidal conveyor screw placed above the air inlet orifice. This screw is removable and conveniently returns the bed to its conventional spouted configuration. Experiments on drying solutions (calcium carbonate suspensions and skimmed milk) and granular materials (porous alumina particles) were performed for various bed parameter settings. The spouting pressure drop, outlet air temperature, and relative humidity were measured over time under different conditions. Mechanical agitation is proved effective in drying diluted carbonate calcium liquid suspensions and coarse porous alumina particles at an air velocity approximately 50% lower in comparison to drying in a conventional spouted bed. The conventional spouted bed performed better at drying liquid skimmed milk as the mechanical agitation combined with the axial inlet air flow is not effective in mitigating sticking and powder agglomeration in the bed when handling pastes of complex composition. Introducing mechanical agitation in the designed setup broadens the operating range of a conventional spouted bed with axial air flow in the inlet. 展开更多
关键词 Characteristic curve DRYING KINETIC Spouted-bed dynamics Mechanical AGITATION ALUMINA particles PASTE DRYING
Production of composites with high relative permittivity using the spouted bed technique
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作者 E. Eichner P.-K. Fischer +1 位作者 S. Heinrich GA Schneider 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第1期184-189,共6页
This contribution presents a new application of the spouted bed technique. The developed production process involves coating fine copper particles with a polymer in a spouted bed plant and then hot pressing the produc... This contribution presents a new application of the spouted bed technique. The developed production process involves coating fine copper particles with a polymer in a spouted bed plant and then hot pressing the produced granules to form a compact consisting of a copper–polymer composite with a high filling degree. The fabricated composites possess high relative permittivity, which is advantageous for the production of effective capacitors. With increasing filling degree of copper, the relative permittivity of the composites increased, with a maximum relative permittivity of 214 obtained for the composite containing 78.1 vol% copper. Such a high filling degree can be achieved with conductive particles without obtaining a conductive composite by using the spouted bed technology in the production process. The high relative permittivity results from the high filling degree of particles isolated by a polymer coating. 展开更多
关键词 Spouted BED HIGH RELATIVE PERMITTIVITY FINE PARTICLES Coating Metal-polymer composite
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