检索结果-内蒙古大学图书馆

Journal of Advanced Manufacturing and Processing 2019年第1-2期1卷

作者： Xu, Ji Liu, Xingchi Hu, Shanwei Ge, Wei State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing China School of Chemistry and Chemical Engineering University of Chinese Academy of Sciences Beijing China Tianjin 300072 China

The combination of (quasi-)real-time simulation on industrial processes and virtual reality technologies may lead to a new paradigm of research and development in chemical engineering, that is, virtual process engineering (VPE). However, as the main engines of VPE, accurate and efficient simulation methods are still in urgent demand. In this paper, with substantial improvements to a discrete particle method (DPM), namely, energy-minimization multiscale (EMMS)-DPM, such an engine was established for a typical multiphase system, the circulating fluid beds (CFBs). To improve the accuracy, the coupling of particle and fluid flow solvers was updated to be more sensitive to local flow structures, and different drag laws were used for different flow regimes. To speed up the computation, heterogeneous central processing unit (CPU)-graphics processing unit (GPU) computing is developed for solving the fluids and particles. A two-layer domain decomposition method is developed to improve the load balance for real applications with complex geometries. Thus, a computer virtual experiment on a three-dimensional (3D) full-loop CFB has been achieved by simulating 1.27 × 1011 real particles with 1.27 × 108 coarse-grained particles at the speed of 1.5 × 107 particle updates per GPU per second on 135 NVIDA K80 GPUs. To our knowledge, this is the largest-scale and highest-performance DPM simulation of a 3D full-loop CFB in terms of the computational particles used. It is a strong indication that VPE can be realized for industrial systems in the near future. © 2019 American Institute of Chemical Engineers

关键词： Program processors

来源：评论

学校读者我要写书评

暂无评论

A mixed discontinuous galerkin method for linear elasticity with strongly imposed symmetry

arXiv

引用

arXiv 2019年

作者： Wang, Fei Wu, Shuonan Xu, Jinchao School of Mathematics and Statistics and State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi710049 China School of Mathematical Sciences Peking University Beijing100871 China Department of Mathematics Pennsylvania State University University ParkPA16802 United States

In this paper, we study a mixed discontinuous Galerkin (MDG) method to solve linear elasticity problem with arbitrary order discontinuous finite element spaces in d-dimension (d = 2, 3). This method uses polynomials of degree k + 1 for the stress and of degree k for the displacement (k > 0). The mixed DG scheme is proved to be well-posed under proper norms. Specifically, we prove that, for any k > 0, the H(div)-like error estimate for the stress and L2 error estimate for the displacement are optimal. We further establish the optimal L2 error estimate for the stress provided that the Pk+2 - P-1 k+1 Stokes pair is stable and k > d. We also provide numerical results of MDG showing that the orders of convergence are actually sharp.65N30, 65M60 Copyright © 2019, The Authors. All rights reserved.

关键词： Galerkin methods

来源：评论

学校读者我要写书评

暂无评论

Exploration over combined impacts of modified piston bowl geometry and tert -butyl hydroquinone additive-included biodiesel/diesel blend on diesel engine behaviors

引用

Fuel 2022年 322卷

作者： Krupakaran Radhakrishnan Lawrence Zuohua Huang Xuan Phuong Nguyen Dhinesh Balasubramanian Vidyasagar Reddy Gangula Raghurami Reddy Doddipalli Van Vang Le Sachuthananthan Bharathy Anh Tuan Hoang Department of Mechanical Engineering Sree Vidyanikethan Engineering College Tirupati Andhra Pradesh India State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an 710049 China PATET Research Group Ho Chi Minh City University of Transport Ho Chi Minh City Viet Nam Department of Mechanical Engineering Mepco Schlenk Engineering College Sivakasi India Mechanical Engineering Faculty of Engineering Khon Kaen University Khon Kaen Thailand Center for Alternative Energy Research and Development Khon Kaen University Khon Kaen Thailand Institute of Maritime Ho Chi Minh City University of Transport Ho Chi Minh City Viet Nam Institute of Engineering HUTECH University Ho Chi Minh City Viet Nam

Nowadays, the use of biodiesel for diesel engines has been attracting researchers aiming to improve engine characteristics although the engine performance could be decreased while utilizing biodiesel. In this aspect, optimizing the piston bowl geometry is one of the useful approaches to enhance the efficiency of the biodiesel-powered diesel engine. In this study, the standard piston of an existing diesel engine was modified into two different combustion bowls, namely Symmetrical Stepped Curved-V (SSCV) and Symmetrical Spline-V (SSV), to evaluate the CI engine performance powered with mixtures of sesame-originated biodiesel, diesel fuel, and tert -butyl hydroquinone (TBHQ) additive through two-stage experiment. In the first phase, experiments were carried out on two modified piston bowls powered by diesel and S20 (20% sesame biodiesel + 80% diesel fuel). Resultantly, SSV piston revealed superior engine characteristics to SSCV piston and standard piston due to enhanced air–fuel mixing and more complete combustion of SSV piston-based engine. Indeed, SSV piston operation exhibited an 8.68% of increased brake thermal efficiency (BTE), 6.54% of curtailed brake-specific fuel consumption (BSFC), 4.76% of lowered carbon monoxide (CO), 4.84% of decreased unburnt hydrocarbon (HC), and 2.22% of lowered smoke opacity but with increased nitrogen oxide (NOx) by 14.14% in comparison to diesel. In the 2nd phase, to control the NOx emission effectively, a TBHQ additive was added to the S20 sample at different proportions (500 mg and 1000 mg) to analyze the test engine behaviors with modified piston shapes. As a result, S20 + 500 mg TBHQ at 100% load improved BTE by 5.79% and reduced BSFC by 4.36% in the case of SSV piston. Moreover, it curtailed emissions of CO, HC, NOx, and smoke opacity by 13.33%, 15.49%, 12.09%, and 9.44%, respectively, when equated with diesel. Overall, S20 + 500 mg TBHQ could be thought of as a possible alternative fuel on SSV piston as it resulted in superior p

关键词：

来源：评论

学校读者我要写书评

暂无评论

Modulating the Electronic Metal-Support Interactions in Single-Atom Pt1−CuO Catalyst for Boosting Acetone Oxidation

引用

Angewandte Chemie 2022年第28期134卷

作者： Dr. Zeyu Jiang Dr. Mingjiao Tian Dr. Meizan Jing Prof. Shouning Chai Dr. Yanfei Jian Dr. Changwei Chen Prof. Mark Douthwaite Dr. Lirong Zheng Dr. Mudi Ma Prof. Weiyu Song Prof. Jian Liu Prof. Jiaguo Yu Prof. Chi He State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi P. R. China Department of Chemistry National University of Singapore Singapore 117543 Singapore Laboratory of Solar Fuel Faculty of Materials Science and Chemistry China University of Geosciences Wuhan 430074 P. R. China State Key Laboratory of Heavy Oil Processing China University of Petroleum Beijing 102249 P. R. China Max Planck-Cardiff Centre on the Fundamentals of Heterogeneous Catalysis School of Chemistry Cardiff University Cardiff CF10 3AT UK Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 P. R. China National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing 101408 P. R. China

The development of highly active single-atom catalysts (SACs) and identifying their intrinsic active sites in oxidizing industrial hazardous hydrocarbons are challenging prospects. Tuning the electronic metal-support interactions (EMSIs) is valid for modulating the catalytic performance of SACs. We propose that the modulation of the EMSIs in a Pt 1 −CuO SAC significantly promotes the activity of the catalyst in acetone oxidation. The EMSIs promote charge redistribution through the unified Pt−O−Cu moieties, which modulates the d -band structure of atomic Pt sites, and strengthens the adsorption and activation of reactants. The positively charged Pt atoms are superior for activating acetone at low temperatures, and the stretched Cu−O bonds facilitate the activation of lattice oxygen atoms to participate in subsequent oxidation. We believe that this work will guide researchers to engineer efficient SACs for application in hydrocarbon oxidation reactions.

关键词： Acetone Oxidation Electronic Metal-Support Interactions Intrinsic Mechanism Single-Atom Catalysts

来源：评论

学校读者我要写书评

暂无评论

Chargeable photoconductivity in Van der Waals heterojunctions

arXiv

引用

arXiv 2020年

作者： Jiang, Yucheng He, Anpeng Chen, Yu Liu, Guozhen Lu, Hao Zhao, Run Long, Mingshen Gao, Ju Wu, Quanying Ge, Xiaotian Ning, Jiqiang Hu, Weida Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Mathematics and Physics Suzhou University of Science and Technology Suzhou Jiangsu215009 China State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences 500 Yu Tian Road Shanghai200083 China School for Optoelectronic Engineering Zaozhuang University Shandong277160 China Suzhou Jiangsu215009 China

Van der Waals (vdW) heterojunctions, based on two-dimensional (2D) materials, show great potential for the development of eco-friendly and high-efficiency nanodevices. Considerable research has been performed and has reported valuable applications of photovoltaic cells, photodetectors, etc. However, simultaneous energy conversion and storage in a single device has not been achieved. Here, we demonstrate a simple strategy to construct a vdW p-n junction between a WSe2 layer and quasi-2D electron gas. After once optical illumination, the device stores the light-generated electrons and holes for up to seven days, and then releases a very large photocurrent of 2.9 mA with bias voltage applied in darkness;this is referred to as chargeable photoconductivity (CPC), which completely differs from any previously observed photoelectric phenomenon. In normal photoconductivity, the recombination of electron-hole pairs takes place at the end of their lifetime, causing a release of heat;in contrast, infinite-lifetime photocarriers can be generated in CPC devices without a thermal loss. The photoelectric conversion and storage are completely self-excited during the charging process. The ratio between currents in full- and empty-energy states below the critical temperature reaches as high as 109, with an external quantum efficiency of 4410000% during optical charging. A theoretical model developed to explain the mechanism of this effect is in good agreement with the experimental data. This work paves a path towards storage-type photoconductors and high-efficiency entropy-decreasing devices. Copyright © 2020, The Authors. All rights reserved.

关键词： Van der Waals forces

来源：评论

学校读者我要写书评

暂无评论

Cobalt oxide and carbon modified hematite nanorod arrays for improved photoelectrochemical water splitting

引用

Chinese Chemical Letters 2017年第12期28卷 2207-2211页

作者： Miao Wang Meng Wang Yanming Fu Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an fiaotong UniversityXi'on 710049China

Given the proper band gap, low cost and good stability, hematite （α-Fe2O3） has been considered as a promising candidate for photoelectrochemical （PEC） water splitting, however suffers from the sluggish surface water oxidation reaction kinetics. In this study, a simple dip-coating process was used to modify the surface of α-Fe2O3 nanorod arrays with cobalt oxide （COOx） and carbon （C） for the improved PEC performance, with a photocurrent density at 1.6V （vs. reversible hydrogen electrode, RHE） increased from 0.10 mA/cm2 for the pristine α-Fe2O3 to 0.37 mA/cm2 for the CoOx/C modified α-Fe2O3 nanorods. As revealed by electrochemical analysis, thanks to the synergistic effect of CoOx and C, the PEC enhancement could be attributed to the enhanced charge transfer ability, decreased surface charge recombination, and accelerated water oxidation reaction kinetics. This study serves as a good example for improving PEC water splitting performance via a simple method.

关键词： Hematite nanorodsSurface modificationPhotoelectrochemical water splittingWater oxidationElectrochemical impedance spectroscopy

来源：评论

学校读者我要写书评

暂无评论

Preparation and characterization of high softening point and homogeneous isotropic pitches produced from distilled ethylene tar by a novel bromination method

引用

新型炭材料 2018年第1期33卷 97-100页

作者： Chuan-zhang Ge Zhen-long Sun Hai-xiao Yang Dong-hui Long Wen-ming Qiao Li-cheng Ling State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Multiphase Materials Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar (ET-HR) by a two-step method of bromination and subsequent dehydrobromination/polycondensation. The ET-HR was first brominated at 30 or 200 ^oC, and then heat-treated at 350 ^oC to enable the dehydrobromination/polycondensation reactions. GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3- to 6-ring aromatic species with a considerable aliphatic chain content. Compared with thermal condensation alone, such a two-step method increased the softening point of the pitches from 152 to 264 ^oC with a yield in the range of 62 wt. %−67 wt.% and a coking value in the range of 57 wt. %−77 wt.%, depending on the bromination temperature and the bromine content. Structural characterization of the as-prepared pitches by elemental analysis, ¹H NMR, FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobromination/polycondensation. All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800 °C.

关键词： high softening point and homogeneous isotropic pitches produced from distilled ethylene tar romination method

来源：评论

学校读者我要写书评

暂无评论

New technology of ionic liquid-based NH3/CO2 separation from melamine tail gas

引用

Green Chemical engineering 2020年第1期1卷 5-5页

作者： Shaojuan Zeng Haifeng Dong Yinge Bai Xiangping Zhang Suojiang Zhang CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing100190China

Melamine is an important industrial raw material,and widely used in the production of thermal insulation materials,adhesives,fiber materials and so ***,every 1 ton of melamine produced through decomposition and condensation reaction using urea generates about 2.2 tons of tail gas containing about 70%NH_(3)and 29%CO_(2).According to the phase diagram of NH_(3)–CO_(2)-AM(ammonium carbamate),NH_(3)and CO_(2)are easy to react and form AM solid under 63C at ambient pressure,which make it difficult to selective recovery of NH_(3).Water scrubbing is the mostly used technology in industries,but this method demands high energy consumption and discharges a large amount of NH_(3)-containg wastewater,which seriously restricts the sustainable development of industries.

关键词： insulation ambient restrict

来源：评论

学校读者我要写书评

暂无评论

Cover Feature: Hollow Carbon Sphere-Modified Graphitic Carbon Nitride for Efficient Photocatalytic H2Production (Chem. Eur. J. 68/2021)

引用

Chemistry – A European Journal 2021年第68期27卷

作者： Dr. Jinghua Li Dr. Lunqiao Xiong Dr. Bing Luo Prof. Dengwei Jing Dr. Jiamei Cao Prof. Junwang Tang International Research Center for Renewable Energy & State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 P. R. China Department of Chemical Engineering University College London London WC1E 7JE UK School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an Shaanxi 710049 P. R. China

来源：评论

学校读者我要写书评

暂无评论

A mixed discontinuous Galerkin method with symmetric stress for Brinkman problem based on the velocity-pseudostress formulation

arXiv

引用

arXiv 2019年

作者： Qian, Yanxia Wu, Shuonan Wang, Fei Wang, Fei School of Mathematics and Statistics Xi'An Jiaotong University Xi'an Shaanxi710049 China School of Mathematical Sciences Peking University Beijing100871 China School of Mathematics and Statistics State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an Shaanxi710049 China

The Brinkman equations can be regarded as a combination of the Stokes and Darcy equations which model transitions between the fast flow in channels (governed by Stokes equations) and the slow flow in porous media (governed by Darcy?fs law). The numerical challenge for this model is the designing of a numerical scheme which is stable for both the Stokes-dominated (high permeability) and the Darcy-dominated (low permeability) equations. In this paper, we solve the Brinkman model in n dimensions (n = 2, 3) by using the mixed discontinuous Galerkin (MDG) method, which meets this challenge. This MDG method is based on the pseudostress-velocity formulation and uses a discontinuous piecewise polynomial pair PSk+1-Pk(k ≥ 0), where the stress field is symmetric. The main unknowns are the pseudostress and the velocity, whereas the pressure is easily recovered through a simple postprocessing. A key step in the analysis is to establish the parameter-robust inf-sup stability through specific parameter-dependent norms at both continuous and discrete levels. Therefore, the stability results presented here are uniform with respect to the permeability. Thanks to the parameter-robust stability analysis, we obtain optimal error estimates for the stress in broken H(div)-norm and velocity in L2-norm. Furthermore, the optimal L2 error estimate for pseudostress is derived under certain conditions. Finally, numerical experiments are provided to support the theoretical results and to show the robustness, accuracy, and flexibility of the MDG method. Copyright © 2019, The Authors. All rights reserved.

关键词： Stability

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：