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Sonic velocity in holographic fluids and its applications
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作者 胡亚鹏 田雨 +2 位作者 吴小宁 李怀繁 张宏升 《中国物理C:英文版》 SCIE CAS CSCD 2019年第1期65-74,共10页
Gravity/fluid correspondence acts as an important tool in investigating the strongly correlated fluids. We carefully investigate the holographic fluids at the finite cutoff surface by considering different boundary co... Gravity/fluid correspondence acts as an important tool in investigating the strongly correlated fluids. We carefully investigate the holographic fluids at the finite cutoff surface by considering different boundary conditions in the scenario of gravity/fluid correspondence. We find that the sonic velocity of the boundary fluids at the finite cutoff surface is critical in clarifying the superficial similarity between the bulk viscosity and perturbation of the pressure for the holographic fluid, where we set a special boundary condition at the finite cutoff surface to explicitly express this superficial similarity. Moreover, we further take the sonic velocity into account to investigate a case with a more general boundary condition. In this more genaral case, although two parameters in the first order stress tensor of holographic fluid cannot be fixed, one can still extract the information about the transport coefficients by considering the sonic velocity seriously. 展开更多
关键词 gravity/fluid CORRESPONDENCE boundary condition BULK VISCOSITY sonic velocity
Energy calibration of a CR-39 nuclear-track detector irradiated by charged particles 预览
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作者 Yue Zhang Hong-Wei Wang +5 位作者 Yu-Gang Ma Long-Xiang Liu Xi-Guang Cao Gong-Tao Fan Guo-Qiang Zhang De-Qing Fang 《核技术:英文版》 SCIE CAS CSCD 2019年第6期1-9,共9页
Charged particle diagnosis is an important aspect of laser–plasma experiments conducted at super-intense laser facilities. In recent years, Columbia Resin #39 (CR- 39) detectors have been widely employed for detectin... Charged particle diagnosis is an important aspect of laser–plasma experiments conducted at super-intense laser facilities. In recent years, Columbia Resin #39 (CR- 39) detectors have been widely employed for detecting charged particles in laser–plasma experiments. This is because the CR-39 polymer does not respond to electromagnetic pulses or X-rays. This study presents a method for calibrating the relationship between particle energy and track diameter in a CR-39 detector (TasTrak■) using 3-8 MeV protons, 6-30 MeV carbon ions, and 1–5 MeV alpha particles. The particle tracks were compared under the manufacturer’s recommended etching conditions of 6.25 mol/l NaOH at 98℃ and under the widely adopted experimental conditions of 6.25 mol/l NaOH at 70℃. The results show that if the NaOH solution concentration is 6.25 mol/l, then the temperature of 70℃is more suitable for etching proton tracks than 98℃ and employing a temperature of 98 ℃ to etch alpha-particle and carbon-ion tracks can significantly reduce the etching time. Moreover, this result implies that C3+ ion or alpha-particle tracks can be distinguished from proton tracks with energy above 3 MeV by controlling the etching time. This calibration method for the CR-39 detector can be applied to the diagnosis of reaction products in laser–plasma experiments. 展开更多
关键词 CR-39 DETECTOR Energy calibration BULK ETCH rate ETCHING temperature
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Call for Papers Special Issue on “Single-cell Omics Analysis”
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《基因组蛋白质组与生物信息学报:英文版》 CAS CSCD 2019年第2期222-223,共2页
The cell has been primarily studied as a part of its bulk population for decades until recent breakthroughs in single-cell omics technologies. The study of the seemingly isogenic cellular populations often buries dive... The cell has been primarily studied as a part of its bulk population for decades until recent breakthroughs in single-cell omics technologies. The study of the seemingly isogenic cellular populations often buries diverse cellular characteristics. Even in cells with the same cellular history,heterogeneity inherently arises due to the stochastic fluctuation of gene expression during transcription and translation or noises in signaling pathways. These hidden cell-to-cell variations can be paramount in the diagnosis and treatment of disease. For instance,the heterogeneity in tumor cells is crucial in understanding tumor initiation,progression,metastasis,and therapeutic response. A very small subpopulation of cells that may confer the most resistance in a preclinical drug test could be responsible for tumor relapse in patients after treatment. Thus,as medicine becomes more and more personalized,there is a greater desire to more accurately represent and understand single cells and the distinct subpopulations. 展开更多
关键词 PAPERS Special ISSUE SINGLE-CELL OMICS ANALYSIS a part of its BULK population
Distribution and Sources of Organic Matter in Surface Sediments of the Northern Bering and Chukchi Seas by Using Bulk and Tetraether Proxies 预览
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作者 JI Zhongqiang JIN Haiyan +5 位作者 STEIN Ruediger LI Zhongqiao BAI Youcheng LI Hongliang ZHANG Yang CHEN Jianfang 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期563-572,共10页
The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic ca... The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic carbon (OC) in the surface sedi-ments of the northern Bering and Chukchi Seas remain limited. Here a multiproxy approach based on bulk OM parameters and the branched vs. isoprenoid tetraether (BIT) index was used to investigate the distribution and sources of OM in the surface sediments of the northern Bering and Chukchi Seas. Binary and ternary mixing models were applied to trace the contribution of different OC sources to the total OC in the study area. The δ13C values of the sediments provided by the binary model showed that the proportion of terrestrial OC fell in the range of 27.4%–79.8% (46.2% on average). The BIT index returned the lowest fraction (4.8%–27.3%, 12.0% on average). The ternary mixing model was employed to determine the plant-, soil-, and marine-derived fractions of the total OM. The ternary model showed that 11.5%±6.3%, 31.4%±9.5%, and 57.1%±12.4% of OM in the sediment of the study area was derived from soil, plants, and marine sources, respectively. The differences in OM composition between the west and east sides of the Chukchi Sea were controlled by OM inputs from key water masses (i.e., Anadyr Water and Alaska Coastal Water), river discharge, and the nutrient supply from the Pacific inflow that supports marine productivity. 展开更多
关键词 northern BERING SEA CHUKCHI SEA organic matter GDGTs BULK parameters
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Dependency of well-contact density on MCUs in 65-nm bulk CMOS SRAM
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作者 Cheng XIE Yueyue CHEN +1 位作者 Jianjun CHEN Jizuo ZHANG 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第6期171-173,共3页
Dear editor,In custom static random access memory (SRAM)cell, radiation-induced single bit upsets (SBUs)are considered as the main cause of soft error [1].Advanced technologies and scaling down of feature sizes have m... Dear editor,In custom static random access memory (SRAM)cell, radiation-induced single bit upsets (SBUs)are considered as the main cause of soft error [1].Advanced technologies and scaling down of feature sizes have made single-event multiple cell upsets (MCUs) as the vital source of soft error. 展开更多
关键词 DEPENDENCY of well-contact DENSITY on MCUs in 65-nm BULK CMOS SRAM MCU
Exploring alkylthiol additives in PBDB-T:ITIC blended active layers for solar cell applications
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作者 李想 何志群 +6 位作者 孙盟杰 张慧敏 郭泽邦 许亚军 李瀚 梁春军 荆西平 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第8期425-432,共8页
Bulk heterojunction,non-fullerene PBDB-T:ITIC blend polymer solar cells have been fabricated.The active layers consisting of PBDB-T as a donor and ITIC as an acceptor are optimized using a series of alkylthiol additiv... Bulk heterojunction,non-fullerene PBDB-T:ITIC blend polymer solar cells have been fabricated.The active layers consisting of PBDB-T as a donor and ITIC as an acceptor are optimized using a series of alkylthiol additives(1,3-propanedithiol,1,4-butanedithiol,and 1,8-octanedithiol).It is found that the donor and acceptor are phase separated with different crystalline domains.The additives effectively re-organize the morphology and extend the molecule ordering in lamellar structure with increased correlation length in ITIC domain,benefiting the generation and dissociation of exciton and reducing charge recombination.A substantial improvement in power conversion efficiency of the devices from 8.13%to 9.44%is observed.This study shows that the application of alkylthiol additives is a simple and effective approach to improve the device performance in solar cells based on polymer/non-fullerene blend system. 展开更多
关键词 bulk heterojunction(BHJ)polymer/non-fullerene solar cells solvent ADDITIVE morphology CRYSTALLIZATION
Optimal bulk-heterojunction morphology enabled by fibril network strategy for high-performance organic solar cells
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作者 Tian Xia Yunhao Cai +1 位作者 Huiting Fu Yanming Sun 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第6期662-668,共7页
A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction(BHJ) organic solar cells(OSCs). Many donor-acceptor(D-A) type conjugated polymers can self-assemble into po... A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction(BHJ) organic solar cells(OSCs). Many donor-acceptor(D-A) type conjugated polymers can self-assemble into polymer fibrils in the solid state and such fibril-assembly can construct the morphological framework by forming a network structure, inducing the formation of ideal BHJ morphology. Our recent works have revealed that the fibril network strategy(FNS) can control the blend morphology in fullerene, non-fullerene and ternary OSCs. It has been shown that the formation of fibril network can optimize phase separation scale and ensure efficient exciton dissociation and charge carriers transport, thus leading to impressive power conversion efficiencies(PCEs) and high fill factor(FF) values. We believe that FNS will provide a promising approach for the optimization of active layer morphology and the improvement of photovoltaic performance, and further promote the commercialization of OSCs. 展开更多
关键词 organic solar cells BULK HETEROJUNCTION polymer FIBRIL FIBRIL network strategy MORPHOLOGY
本体光交联对热塑性淀粉塑料性能的影响 预览
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作者 周文 陈春昊 +3 位作者 缪中美 席梦华 郭斌 曹绪芝 《中国塑料》 CAS CSCD 北大核心 2019年第6期44-49,共6页
将光引发剂二苯甲酮直接与淀粉和甘油共混,并通过挤出注塑工艺制备了热塑性淀粉(TPS)塑料,研究了不同紫外光照时长对其力学、动态热力学、热稳定和耐水性能的影响。结果表明,当紫外光照时长为15min时,TPS可形成最佳的交联网络结构,显著... 将光引发剂二苯甲酮直接与淀粉和甘油共混,并通过挤出注塑工艺制备了热塑性淀粉(TPS)塑料,研究了不同紫外光照时长对其力学、动态热力学、热稳定和耐水性能的影响。结果表明,当紫外光照时长为15min时,TPS可形成最佳的交联网络结构,显著提高其性能,拉伸强度,弯曲强度,冲击强度分别可达4.57MPa、7.1MPa及69.39kJ/m2;储能模量有所提高,玻璃化转变温度达到最高,Tβ和Tα分别为-35.63℃和53.96℃;最大分解速率对应的峰值温度(Tp)由TPS的317.81℃提高到330.48℃;表面接触角由纯TPS的42.3°增加至77.2°,显著提高了耐水性能。 展开更多
关键词 热塑性淀粉 本体 紫外交联 力学性能 耐水性能
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海岛环境下大体量场平降方施工技术探讨 预览
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作者 陈庆飞 张仁强 +2 位作者 赵冬 陈春超 赵俊 《电力系统装备》 2019年第7期42-43,共2页
海岛环境下大体量场平降方施工具有工程体量大、技术难度高、交通困难、气候恶劣等特点。为了解决上述难点,本文借鉴过往工程资料,结合镇海-舟山500kV 线路工程(镇舟线副跨)的实际情况,对施工测量、边坡控制、挖方施工、高边坡开挖和填... 海岛环境下大体量场平降方施工具有工程体量大、技术难度高、交通困难、气候恶劣等特点。为了解决上述难点,本文借鉴过往工程资料,结合镇海-舟山500kV 线路工程(镇舟线副跨)的实际情况,对施工测量、边坡控制、挖方施工、高边坡开挖和填方施工等关键技术进行深入探讨,并制定了切实可行的技术方案,可以为今后类似工程提供了一定的参考和借鉴。 展开更多
关键词 海岛 输电铁塔 场平降方 大体量
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基于Excel VBA的批量数据提取工具开发 预览 被引量:1
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作者 刘欢 彭书强 《电脑知识与技术:学术版》 2019年第2Z期196-198,共3页
为了批量提取管道力学计算软件PipeStress输出的结果文件中的数据,需要使用计算机从结果文件中提取支架的反力及反力方向矢量等数据。基于VBA简单易学易用的特点,提出使用Excel电子表格读取结果文件,并使用VBA语言编程进行数据处理的方... 为了批量提取管道力学计算软件PipeStress输出的结果文件中的数据,需要使用计算机从结果文件中提取支架的反力及反力方向矢量等数据。基于VBA简单易学易用的特点,提出使用Excel电子表格读取结果文件,并使用VBA语言编程进行数据处理的方法。经过实际应用表明,该工具能满足实际需求,大大提高了工作效率,节省了大量的人力和时间,使用、维护简便,可靠性高。 展开更多
关键词 批量 数据提取 EXCEL VBA
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Effect of initial material bulk density and easily-degraded organic matter content on temperature changes during composting of cucumber stalk
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作者 Ruixue Chang Qiuyue Guo +3 位作者 Qing Chen Maria Pilar Bernal Qian Wang Yanming Li 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第6期306-315,共10页
To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures(> 70°C) should be maintained during the composting without having an inhibitory effec... To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures(> 70°C) should be maintained during the composting without having an inhibitory effect on maturity. This study investigated the influence of bulk density(part 1) and easily-degraded organic matter content(EDOMC, part 2) on temperature evolution during vegetable waste composting: Part 1: corn straw with different particle sizes was used to achieve different bulk densities in the composting material(BD1–BD3);Part 2: partial or total substitution of the corn straw by corn starch was carried out to obtain different EDOMC(ED1–ED4). The composting experiments were conducted in a labscale reactor(1.75 kg material) and lasted for 30 d. Temperature and CO2 emission were recorded daily, and the organic matter, lignocellulose, microbial activity, germination index(GI) and C/N of the samples were measured at different stages. The highest temperature(65.7°C) in part 1 occurred in the treatment with the bulk density of 0.35 g/cm3, which also had the longest thermophilic phase. Bulk density was found to seriously influence the utilization efficiency of O2 and heat transfer through materials, rather than heat production from organic matter degradation. In experiment part 2, the highest temperature was obtained with EDOMC of 45%(71.4°C). Therefore, adjusting the bulk density to 0.35 g/cm3 and the easily-degraded organic matter content of the initial material to 45% was the best combination for reaching temperatures above 70°C during composting, with no inhibitory effect on the maturity of the compost product. 展开更多
关键词 COMPOST 70℃ Vegetable waste Bulk density Easily-degraded organic matter con TENT CUCUMBER STALK
Highly efficient and flexible preparation of water-dispersed Fe3O4 nanoclusters using a micromixer
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作者 Xiaojing Liu Yangcheng Lu 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第4期42-48,共7页
Solvent exchange is widely used to synthesize magnetic nanoclusters (MNCs).However,it remains a challenge to increase the production and decrease the addition ofsurfactants,both of which are important for the applicat... Solvent exchange is widely used to synthesize magnetic nanoclusters (MNCs).However,it remains a challenge to increase the production and decrease the addition ofsurfactants,both of which are important for the application and functionalization of MNCs.Herein,we use a rapid and tunable mixing method to control the assembly of Fe3O4 nanoparticles.This method involves shear-mixing in a channel of a Tjunction micromixer.Smaller and more monodisperse MNCs were synthesized with less surfactant,when compared with conventional bulk synthesis.Varying the mixing rate and the formula of the magnetic suspension allowed for the flexible adjustment of the nanocluster size while maintaining a uniformly sized MNCs.The flow synthesis and ease of scale-up make this method potentially suitable for broad industrial application. 展开更多
关键词 FE3O4 MAGNETIC nanoparticle MAGNETIC NANOCLUSTER Micromixer-assisted continuous SYNTHESIS Bulk SYNTHESIS
大比例竹浆抄造轻型纸
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作者 蒙衍强 覃健红 石灵高 《纸和造纸》 2019年第4期1-3,共3页
以书刊胶版印刷纸基本生产工艺为基础,通过调整浆料配比、填料用量,并改变打浆工艺、抄造工艺,研究大比例竹浆抄造轻型纸的可行性,并讨论了生产过程中影响轻型纸松厚度、不透明度、表面强度等的各种因素。结果表明:以全漂白化竹浆和化... 以书刊胶版印刷纸基本生产工艺为基础,通过调整浆料配比、填料用量,并改变打浆工艺、抄造工艺,研究大比例竹浆抄造轻型纸的可行性,并讨论了生产过程中影响轻型纸松厚度、不透明度、表面强度等的各种因素。结果表明:以全漂白化竹浆和化机浆按(55~60):(45~40)浆料比,添加适量的辅料,在合适的打浆工艺和抄造工艺技术条件下,可生产出合格的轻型纸。 展开更多
关键词 轻型纸 松厚度 不透明度
What is the mass of loess in the Loess Plateau of China?
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作者 Yuanjun Zhu Xiaoxu Jia +1 位作者 Jiangbo Qiao Ming’an Shao 《科学通报:英文版》 SCIE EI CSCD 2019年第8期534-539,共6页
The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining th... The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining the regional soil and water resource capacity. We used loess thickness data, a pedotransfer function for bulk density(BD), and the clay content data observed in 242 sites across the LP to derive the BD of loess and then estimate the loess mass and its distribution across the LP. The results indicated that the average BD of loess between the surface and bedrock is 1.58 g cm-3, varying from 1.18 to 1.87 g cm-3.The total loess mass is approximately 5.45 ? 1013 t, and the average loess mass over an area of 1 m2 is 169 t, ranging from 1.36 to 585 t. The greatest mass of loess is in the south-central of the LP while the lowest mass of loess is in the northwest and river valley areas. Our estimate of loess mass provides key data for calculating water, carbon, and nutrient storages in the LP, which improves our understanding of soil-water processes and ecohydrological systems in this landscape. 展开更多
关键词 The LOESS PLATEAU LOESS MASS Pedotransfer function Soil EROSION BULK density
Neutral excitation and bulk gap of fractional quantum Hall liquids in disk geometry
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作者 杨武庆 李骐 +1 位作者 杨林鹏 胡自翔 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期20-26,共7页
For the numerical simulation of the fractional quantum Hall(FQH) effects on a finite disk, the rotational symmetry is the only symmetry that is used in diagonalizing the Hamiltonian. In this work, we propose a method ... For the numerical simulation of the fractional quantum Hall(FQH) effects on a finite disk, the rotational symmetry is the only symmetry that is used in diagonalizing the Hamiltonian. In this work, we propose a method of using the weak translational symmetry for the center of mass of the many-body system. With this approach, the bulk properties, such as the energy gap and the magneto-roton excitation are consistent with those in the closed manifolds like the sphere and torus. As an application, we consider the FQH phase and its phase transition in the fast rotated dipolar fermions. We thus demonstrate the disk geometry having versatility in analyzing the bulk properties beside the usual edge physics. 展开更多
关键词 FRACTIONAL quantum Hall BULK STATES edge STATES magneto-roton dipolar–dipolar interaction
Novel Crystallization Behaviors of Zr-Based Metallic Glass Under Thermo-Mechanical Coupled Fatigue Loading Condition
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作者 Zhi-Chao Ma Xiao-Xi Ma +3 位作者 Hong-Wei Zhao Fu Zhang Li-Ming Zhou Lu-Quan Ren 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第7期797-802,共6页
Novel crystallization behaviors of Zr55Cu30Al10Ni5 bulk metallic glass are investigated. On the one hand, mixed oxides, including CuO, CuAlO2, CuA12O4 and ZrO2, show sequential oxidation process determined by coupling... Novel crystallization behaviors of Zr55Cu30Al10Ni5 bulk metallic glass are investigated. On the one hand, mixed oxides, including CuO, CuAlO2, CuA12O4 and ZrO2, show sequential oxidation process determined by coupling effects of specific cyclic load and temperature. On the other hand, at a temperature (100℃) by far lower than Tg of 412 ℃, under cyclic loading condition, non-oxidized binary alloy CuZr2 is precipitated;the thermo-mechanical coupled effects of temperature below Tg, and fatigue accumulation on the non-oxidized crystallization behaviors are revealed. Meanwhile, at a constant temperature of 400 ℃, by comparing among the XRD patterns, respectively, obtained from tensile, creep and fatigue fractures, the dominating effect of cyclic load on the generation of non-oxidized CuZr2 is verified. Furthermore, the crystallization behavior of amorphous phases under cyclic loading condition is observed through TEM micrograph and diffraction pattern at 100℃. 展开更多
关键词 BULK metallic glass FATIGUE THERMO-MECHANICAL coupling CRYSTALLIZATION
DEM parameter calibration of cohesive bulk materials using a simple angle of repose test
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作者 Thomas Roessler Andre Katterfeld 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第4期105-115,共11页
The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test ... The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test has become a standard test for the calibration of DEM parameters of cohesionless bulk materials and is extensively discussed in the literature. One of the most used test methods is the pull-up test of a hollow cylinder filled with bulk material. This paper presents how this basic pull-up test can also be used for the calibration of DEM parameters of cohesive materials by changing the analysis criteria. In contrast to analysing the static angle of repose, the focus lies on the macroscopic flow behaviour during the lifting of the cylinder. Reproducible phases of flow are identified in experiments: the build-up of a stable bulk material column, the convex bending of the column, and the beginning of collapse of the column. Furthermore, the phases are independent of the size and lifting velocity. The convex bending of the bulk-material column combined with the moment of first collapse are introduced as new measurable calibration criteria. These experimental results of wet sand are used for the calibration of related DEM parameters using a simplified JKR cohesion model. The DEM calibration including an analysis algorithm that fits the experimental flow behaviour and the final selection of the relevant parameters (i.e., sliding friction coefficient, rolling friction coefficient, and cohesion energy density) is presented in detail. 展开更多
关键词 DISCRETE ELEMENT method ANGLE of repose COHESIVE BULK material Calibration
Dual-Wavelength Laser Flash Raman Spectroscopy Method for In-Situ Measurements of the Thermal Diffusivity: Principle and Experimental Verification
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作者 FAN Aoran HU Yudong +2 位作者 MA Weigang WANG Haidong ZHANG Xing 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期159-168,共10页
This paper presents an in-situ, non-contact, non-destructive 'dual-wavelength laser flash Raman spectroscopy method' for measuring the thermal diffusivity. In this method, a heating pulse is used to heat the s... This paper presents an in-situ, non-contact, non-destructive 'dual-wavelength laser flash Raman spectroscopy method' for measuring the thermal diffusivity. In this method, a heating pulse is used to heat the sample and another pulsed laser with a different wavelength and negligible heating effect is used as a probe to measure the sample temperature changes during the heating and cooling periods from the Raman peak shifts. The sample temperature rise and fall curves are measured by changing the delay between the heating pulse and the probing pulse with the thermal diffusivity then characterized by fitting the temperature curves. The time delay between the heating and probing pulses can be precisely controlled with a minimum step of 100 ps. Hence, the temperature variation can be scanned with an ultra-high temporal resolution of up to 100 ps, which significantly improves the measurement accuracy of transient thermal parameters. The measurement accuracy of this method has been verified using a bulk material model and experiments. The measured thermal diffusivity of a silicon sample has been obtained to be 8.8×10-5 m2/s with a 3% difference between the measured value and the average result for bulk silicon in the literature which verifies the reliability and accuracy of this method. 展开更多
关键词 DUAL-WAVELENGTH laser flash RAMAN SPECTROSCOPY METHOD thermal DIFFUSIVITY RAMAN SPECTROSCOPY nanomaterials bulk materials
Size effect of lead-free halide double perovskite on luminescence property
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作者 Peigeng Han Xue Zhang +8 位作者 Xin Mao Bin Yang Songqiu Yang Zha Zhochi Feng Donghui Wei Weiqiao Deng Tonu Pullerits Keli Han 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第10期1405-1413,共9页
Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.He... Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs2AgBi1-xInxCl6(0<x<1).The Cs2AgBi0.125In0.875Cl6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs2AgBi0.125In0.875Cl6nanocrystals and Cs2AgBi0.125In0.875Cl6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs2AgBi0.125In0.875Cl6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting. 展开更多
关键词 double perovskite bulk crystals warm white size effect STABILITY
Effects of various donor:acceptor blend ratios on photophysical properties in non-fullerene organic bulk heterojunctions
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作者 Zhenchuan Wen Xuejian Ma +5 位作者 Xiaoyu Yang Pengqing Bi Mengsi Niu Kangning Zhang Lin Feng Xiaotao Hao 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第5期995-999,共5页
The composition ratio of donor and acceptor materials in organic bulk heterojunction (BHJ) is one of the key parameters to govern the performance in organic solar cells (OSCs). Therefore, high-performance non-fulleren... The composition ratio of donor and acceptor materials in organic bulk heterojunction (BHJ) is one of the key parameters to govern the performance in organic solar cells (OSCs). Therefore, high-performance non-fullerene organic bulk heterojunction consisting of poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b' ]dithiophene))-co-(1,3-di(5-thiophene-2-yl)–5,7-bis(2-ethylhexyl) benzo[1,2-c:4,5-c']dithiophene-4,8-dione)] (PBDB-T) and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))–5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2' ,3'-d' ]-s-indaceno[1,2-b:5,6-b' ]-dithio-phene (ITIC) are used to investigate the correlation among various donor: acceptor (D:A) ratios, photophysical properties and photovoltaic performance. Interestingly, the function of short-circuit current (Jsc) and D:A ratios demonstrates an axisymmetric trend. When the blending ratio of D:A deviates from the optimal ratio, the symmetrically decreased Jsc is derived from a reduction in the D:A interface or amorphous region. Research on the steady-state photoluminescence (PL), the time-resolved fluorescence spectroscopy measurements, atomic force microscopic (AFM) and grazing-incidence small angle X-rays scattering (GIWAXS) indicates no significant variation in energy loss in the process of changing D:A ratios in BHJs. With high donor or acceptor content, the domain size improves significantly, but the distance of π-π stacking corresponding to molecular packing has not changed significantly, and the bi-continuous percolation pathways were not obviously influenced. 展开更多
关键词 Photophysical properties Non-fullerene Bulk HETEROJUNCTIONS VARIOUS blend ratios ORGANIC solar cells
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