检索结果-南通市图书馆

High-Performance Perovskite Quantum Dot Solar Cells Enabled by Incorporation with Dimensionally Engineered Organic Semiconductor

引用

Nano-Micro Letters 2022年第12期14卷 272-285页

作者： Seyeong Lim Dae Hwan Lee Hyuntae choi Yelim choi Dong Geon Lee Sung Beom Cho Seonkyung Ko Jongmin choi Younghoon Kim Taiho Park Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Materials Science and Engineering Hanyang UniversitySeoul 04763Republic of Korea Center of Materials Digitalization Korea Institute of Ceramic Engineering and Technology(KICET)Jinju 52851Republic of Korea Department of Materials Science and Engineering Ajou UniversitySuwon 16499Republic of Korea Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu 42988Republic of Korea Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea

Perovskite quantum dots(PQDs)have been considered promising and effective photovoltaic absorber due to their superior optoelectronic properties and inherent material merits combining perovskites and ***,they exhibit low moisture stability at room humidity(20-30%)owing to many surface defect sites generated by inefficient ligand exchange *** surface traps must be re-passivated to improve both charge transport ability and moisture *** address this issue,PQD-organic semiconductor hybrid solar cells with suitable electrical properties and functional groups might dramatically improve the charge extraction and defect *** organic semiconductors are typically low-dimensional(1D and 2D)and prone to excessive self-aggregation,which limits chemical interaction with *** this work,we designed a new 3D star-shaped semiconducting material(Star-TrCN)to enhance the compatibility with *** robust bonding with Star-TrCN and PQDs is demonstrated by theoretical modeling and experimental *** Star-TrCN-PQD hybrid films show improved cubic-phase stability of CsPbI_(3)-PQDs via reduced surface trap states and suppressed moisture *** a result,the resultant devices not only achieve remarkable device stability over 1000 h at 20-30%relative humidity,but also boost power conversion efficiency up to 16.0%via forming a cascade energy band structure.

关键词： CsPbI3 quantum dots Star-shaped organic semiconductors Hybrid perovskite quantum dots Solar cell stability High-efficiency photovoltaics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Groundwater contamination and natural attenuation capacity at a petroleum spilled facility in Korea

引用

Journal of Environmental Sciences 2011年第10期23卷 1650-1659页

作者： Hyun-Mi choi Jin-Yong Lee Department of Geology Kangwon National University

As a remedial option, the natural attenuation capacity of a petroleum contaminated groundwater at a military facility was examined. Hydrogeological conditions, such as high water level, permeable uppermost layer and frequent heavy rainfall, were favorable to natural attenuation at this site. The changes in the concentrations of electron acceptors and donors, as well as the relevant hydrochemical conditions, indicated the occurrence of aerobic respiration, denitrification, iron reduction, manganese reduction and sulfate reduction. The calculated BTEX expressed biodegradation capacity ranged between 20.52 and 33.67 mg/L, which appeared effective for the reduction of the contaminants levels. The contribution of each electron accepting process to the total biodegradation was in the order： denitrification 〉 iron reduction 〉 sulfate reduction 〉 aerobic respiration 〉 manganese reduction. The BTEX and benzene point attenuation rates were 0.0058-0.0064 and 0.0005-0.0032 day-1, respectively, and the remediation time was 0.7-1.2 and 2.5-30 years, respectively. The BTEX and benzene bulk attenuation rates were 8.69 × 10^-4 and 1.05 × 10^-3 day-l, respectively, and the remediation times for BTEX and benzene were 7.2 and 17.5 years, respectively. However, most of the natural attenuation occurring in this site can be attributed to dilution and dispersion. Consequently, the biodegradation and natural attenuation capacities were good enough to lower the contaminants levels, but their rates appeared to be insufficient to reach the remediation goal within a reasonable time frame. Therefore, some active remedial measures would be required.

关键词： petroleum contaminated site BTEX electron acceptor expressed biodegradation capacity natural attenuation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Shear deformable finite beam elements for composite box beams

引用

Acta Mechanica Sinica 2014年第2期30卷 223-240页

作者： Nam-Il Kim Dong-Ho choi Department of Architectural Engineering Sejong University Department of Civil and Environmental Engineering Hanyang University

The shear deformable thin-walled composite beams with closed cross-sections have been developed for coupled flexural, torsional, and buckling analyses. A theoretical model applicable to the thin-walled laminated composite box beams is presented by taking into account all the structural couplings coming from the material anisotropy and the shear deformation effects. The current composite beam includes the transverse shear and the restrained warping induced shear deformation by using the first-order shear deformation beam theory. Seven governing equations are derived for the coupled axial-flexural-torsional-shearing buckling based on the principle of minimum total potential energy. Based on the present analytical model, three different types of finite composite beam elements, namely, linear, quadratic and cubic elements are developed to analyze the flexural, torsional, and buckling problems. In order to demonstrate the accuracy and superiority of the beam theory and the finite beam elements developed by this study,numerical solutions are presented and compared with the results obtained by other researchers and the detailed threedimensional analysis results using the shell elements of ABAQUS. Especially, the influences of the modulus ratio and the simplified assumptions in stress-strain relations on the deflection, twisting angle, and critical buckling loads of composite box beams are investigated.

关键词： Thin-walled Composite box beam Deflection Twisting angle Buckling load Shear deformation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Temperature Distribution and Thermal Stresses in Various Conditions of Moving Heating Source during Line Heating Process

引用

Journal of Thermal Science 2012年第1期21卷 82-87页

作者： Yoon Hwan choi Yeon Won Lee Kwang choi Deog Hee Doh Kyoung Joon Kim Department of Mechanical and Automotive Engineering Pukyong National University Steel Structure Research Division Research Institute of Industrial Science & Technology Division of Mechanical and information Engineering Korea Maritime University

Line heating method is widely used to manufacture curved surfaces in ship building. The main factors governing the quality of the manufactured products are the moving velocity of the heating source, heating strength, and heating ways. In this study, the temperature distributions of the heated plate were investigated with the condition that the line heating process was automatic. The temperature variations were also investigated with the changes of those three variables. The numerical results showed that the peak temperature decreased as the moving velocity of the heating source increased. It also revealed that the peak temperatures changed linearly with the changes of the heating source.

关键词： Moving heat source Line heating Thermal stress Residual deformation Conductive heat transfer

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development of a Biomimetic Quadruped Robot

引用

Journal of Bionic Engineering 2007年第4期4卷 193-199页

作者： Thanhtam Ho Sunghac choi Sangyoon Lee Department of Mechanical Design and Production Engineering Konkuk University Seoul 143-701 Korea

This paper presents the design and prototype of a small quadruped robot whose walking motion is realized by two piezocomposite actuators. In the design, biomimetic ideas are employed to obtain the agility of motions and sustainability of a heavy load. The design of the robot legs is inspired by the leg configuration of insects, two joints （hip and knee） of the leg enable two basic motions, lifting and stepping. The robot frame is designed to have a slope relative to the horizontal plane, which makes the robot move forward. In addition, the bounding locomotion of quadruped animals is implemented in the robot. Experiments show that the robot can carry an additional load of about 100 g and run with a fairly high velocity. The quadruped prototype can be an important step towards the goal of building an autonomous mobile robot actuated by piezocomposite actuators.

关键词： quadruped robot piezocomposite actuator bounding locomotion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theory of phonon-modulated electron spin relaxation time based on the projection reduction method

引用

Chinese Physics B 2014年第8期23卷 436-443页

作者： Nam Lyong Kang Sang Don choi Department of Applied Nanoscience Pusan National University Department of Physics Kyungpook National University

This paper introduces a new method for a formula for electron spin relaxation time of a system of electrons interacting with phonons through phonon-modulated spin-orbit coupling using the projection-reduction method. The phonon absorption and emission processes as well as the photon absorption and emission processes in all electron transition processes can be explained in an organized manner, and the result can be represented in a diagram that can provide intuition for the quantum dynamics of electrons in a solid. The temperature （T） dependence of electron spin relaxation times （T1） in silicon is T1 ∝ T-1.07 at low temperatures and T1 ∝ T-3.3 at high temperatures for acoustic deformation constant Pad = 1.4 × 10^7 eV and optical deformation constant Pod = 4.0 × 10^17 eV/m. This means that electrons are scattered by the acoustic deformation phonons at low temperatures and optical deformation phonons at high temperatures, respectively. The magnetic field （B） dependence of the relaxation times is T1 ∝ B-2.7 at 100 K and T1 ∝ B-2.3 at 150 K, which nearly agree with the result of Yafet, T1 ∝ B-3.0- B -2.5.

关键词： electron spin resonance spin-orbit coupling projection-reduction method phonon scattering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Activity Recognition Based on RFID Object Usage for Smart Mobile Devices

引用

Journal of Computer Science & Technology 2011年第2期26卷 239-246页

作者： Jaeyoung Yang Joonwhan Lee Joongmin choi Human-Computer Interaction Institute Carnegie Mellon University Neowiz Internet Inc. Department of Computer Science and Engineering Hanyang University

Activity recognition is a core aspect of ubiquitous computing applications. In order to deploy activity recognition systems in the real world, we need simple sensing systems with lightweight computational modules to accurately analyze sensed data. In this paper, we propose a simple method to recognize human activities using simple object information involved in activities. We apply activity theory for representing complex human activities and propose a penalized naive Bayes classifier for performing activity recognition. Our results show that our method reduces computation up to an order of magnitude in both learning and inference without penalizing accuracy, when compared to hidden Markov models and conditional random fields.

关键词： activity recognition activity theory context-awareness RFID

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

DIRECT NUMERICAL SIMULATIONS OF THE DYNAMICS OF PARTICLES WITH ARBITRARY SHAPES IN SHEAR FLOWS

引用

Journal of Hydrodynamics 2010年第4期22卷 456-465页

作者： choi Choeng Ryul KIM Chang Nyung Department of Mechanical Engineering Kyung Hee University College of Engineering Kyung Hee University Industrial Liaison Research Institute Kyung Hee University

A fluid-structure interaction method based on the arbitrary Lagrangian-Eulerian method and a dynamic mesh method was developed to simulate the dynamics of a rigid particle in shear *** the method,the governing equations for the fluid flow and particle motion were sequentially solved in a two-way coupling *** mesh system was deformed or re-meshed by the dynamic mesh *** method was employed to simulate the dynamics of a single particle suspended in a flow channel and the dynamics of the particle were *** simulation results show that the angular velocity is not only a function of the inclination angle,is but also influenced by the aspect ratio yielding a hysteresis,while the angular velocity obtained from the Keller-Scalak model is a function only of the inclination angle and does not show a *** present simulations clearly demonstrate that the Fluid-Structure Interaction（FSI） module is very stable,accurate and robust.

关键词： particle suspension Fluid-Structure Interaction (FSI) fluid-particle interaction particulate flow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Priority-based adaptive transmission algorithm for medical devices in wireless body area networks(WBANs)

引用

Journal of Central South University 2015年第5期22卷 1762-1768页

作者： KIM Jinhyuk SONG Inseong choi Sangbang Department of Electronic Engineering Inha University

A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the difference in feature-point values that indicate biomedical signal characteristics. Furthermore, we propose a priority-adjustment method that enhances quality of service while guaranteeing signal integrity. A large number of simulations were carried out for performance evaluation. We use electrocardiogram and electromyogram signals as reference biomedical signals for performance verification. From the simulation results, we find that the average packet latency of proposed scheme is enhanced by 30% compared to conventional method. The simulation results also demonstrate that the proposed algorithm achieves significant performance improvement in terms of drop rates of high-priority packets around 0.3%-0.9 %.

关键词： wireless body area network channel efficiency quality of service

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Visualization of flow structures inside a conical spouted bed by electrical capacitance volume tomography

引用

Particuology 2019年第1期17卷 15-25页

作者： Hoon Chae Park Hang Seok choi Department of Environmental Engineering Yonsei UniversityWonju 26493Republic of Korea

Electrical capacitance volume tomography (ECVT) was conducted to measure instantaneous gas–solid flow structures in a conical spouted bed. The sensor has 24 electrodes/channels and was used to make three-dimensional measurements of the solid volume fraction. Flow structures in the conical spouted bed were analyzed using quantitative ECVT images. Three-dimensional images of gas–solid flow structures and time-averaged vertical and radial solid volume fraction profiles are presented. Different fluidization regimes in spouted beds were characterized by analyzing pressure fluctuation signals and ECVT images. ECVT was shown to be robust and powerful for the three-dimensional visualization and quantitative measurement of a gas–solid fluidization system.

关键词： Conical spouted bed Electrical capacitance volume tomography Multiphase flow

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：