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Impact of forest fires on regional air quality in Southeast Asia

Chinese Journal Of Geochemistry 2006年第B8期25卷 221-222页

作者： Rajasekhar Balasubramanian siao wee see Division of Environmental Science and Engineering Department of Chemical and Biomolecular Engineering

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In Situ TEM Observation of the Gasification and Growth of Carbon Nanotubes Using Iron Catalysts

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Nano Research 2011年第8期4卷 767-779页

作者： Xiaofeng Feng see wee Chee Renu Sharma Kai Liu Xu Xie Qunqing Li Shoushan Fan Kaili Jiang Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center Tsinghua University Beijing 100084 China Leroy Eyring Center for Solid State Science Arizona State University Tempe AZ 85287 USA Present address： Department of Materials Science and Engineering University of California Berkeley CA 94720 USA Present Address： Department of Materials Science and Engineerig Rensselaer Polytechnic Institute Troy NY 12180 USA Present address： National Institute of Science and Technology Gaithersburg MD 20899 USA Present address： Department of Materials Science and Engineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA

We report the in situ transmission electron microscope (TEM) observation of the catalytic gasification and growth of carbon nanotubes (CNTs). It was found that iron catalysts can consume the CNTs when pumping out the precursor gas, acetylene, at the growth temperature, and reinitiate the growth when acetylene is re-introduced. The switching between gasification and growth of CNTs can be repeated many times with the same catalyst. To understand the phenomenon, thermogravimetric analysis (TGA) coupled with mass spectroscopy was used to study the mechanism involved. It was shown that the residual water molecules in the growth chamber of the TEM react with and remove carbon atoms of CNTs as carbon monoxide vapor under the action of the catalyst, when the precursor gas is pumped out. This result contributes to a better understanding of the water-assisted and oxygen-assisted synthesis of CNT arrays, and provides useful clues on how to extend the lifetime and improve the activity of the catalysts.

关键词： Carbon nanotubes gasification growth iron catalyst environmental transmission electron microscopy (ETEM),thermogravimetric analysis (TGA)

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Photovoltaic-powered supercapacitors for driving overall water splitting:A dual-modulated 3D architecture

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Carbon Energy 2022年第6期4卷 1262-1273页

作者： Zixu Sun Lijuan Sun see wee Koh Junyu Ge Jipeng Fei Mengqi Yao Wei Hong Shude Liu Yusuke Yamauchi Hong Li Key Lab for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologyCollaborative Innovation Center of Nano Functional Materials and ApplicationsSchool of Materials Science and EngineeringHenan UniversityKaifengPeople's Republic of China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingaporeSingapore School of Electronic and Information Zhongyuan University of TechnologyZhengzhouPeople's Republic of China JST-ERATO Yamauchi Material Space-Tectonics Project National Institute for Materials Science(NIMS)TsukubaIbarakiJapan Australian Institute for Bioengineering and Nanotechnology(AIBN) The University of QueenslandBrisbaneQueenslandAustralia

Due to the growing demand for clean and renewable hydrogen fuel,there has been a surge of interest in electrocatalytic water-splitting devices driven by renewable energy ***,the feasibility of self-driven water splitting is limited by inefficient connections between functional modules,lack of highly active and stable electrocatalysts,and intermittent and unpredictable renewable energy ***,we construct a dualmodulated three-dimensional(3D)NiCo_(2)O_(4)@NiCo_(2)S_(4)(denoted as NCONCS)heterostructure deposited on nickel foam as a multifunctional electrode for electrocatalytic water splitting driven by photovoltaic-powered *** to a stable 3D architecture configuration,abundant active sites,efficient charge transfer,and tuned interface properties,the NCONCS delivers a high specific capacity and rate performance for supercapacitors.A twoelectrode electrolyzer assembled with the NCONCS as both the anode and the cathode only requires a low cell voltage of 1.47 V to achieve a current density of 10 mA cm^(−2) in alkaline electrolyte,which outperforms the state-of-the-art bifunctional *** calculations suggest that the generated heterointerfaces in NCONCS improve the surface binding capability of reaction intermediates while regulating the local electronic structures,which thus accelerates the reaction kinetics of water *** a proof of concept,an integrated configuration comprising a two-electrode electrolyzer driven by two series-connected supercapacitors charged by a solar cell delivers a high product yield with superior durability.

关键词： hybrid energy systems interface engineering morphology control solar-to-hydrogen trifunctional electrode

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基于NVIDIA Kepler的PIC方法并行

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计算机工程与科学 2013年第11期35卷 100-104页

作者：文敏华林新华 Simon Chong wee see 上海交通大学高性能计算中心上海200240 东京工业大学日本东京152-8550 NVIDIA Corporation 新加坡

PIC方法是计算等离子体物理中广泛使用的一种计算方法。通常情况下需要使用大量的计算粒子以达到高的计算精度,这导致非常庞大的计算量。因而PIC方法的加速研究对于减少其时间成本非常有意义。设计了一个基于NVIDIA Kepler GPU的PIC算法... 详细信息

PIC方法是计算等离子体物理中广泛使用的一种计算方法。通常情况下需要使用大量的计算粒子以达到高的计算精度,这导致非常庞大的计算量。因而PIC方法的加速研究对于减少其时间成本非常有意义。设计了一个基于NVIDIA Kepler GPU的PIC算法,并使用CUDA在GPU上实现了该算法。在PIC方法中最耗时间的两个函数collision和mover被移植到GPU上。在实验中使用了NVIDIA新发布的Kepler K20GPU进行这两个函数的性能测试,相比于Intel Sandy Bridge E5-2650,最高获得了30倍的加速。

关键词： PIC方法 CUDA NVIDIA Kepler

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动态网格的DSMC方法在GPU上的并行

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计算机科学与探索 2013年第5期7卷 472-479页

作者：文敏华林新华 Simon Chong wee see 上海交通大学高性能计算中心上海200240 NVIDIA Corporation 美国加利福尼亚圣克拉拉95051

直接模拟蒙特卡罗方法(direct simulation Monte Carlo,DSMC)是稀薄气体动力学领域的重要工具。然而,DSMC方法有两个比较主要的缺点:一是复杂的网格处理;另一个是庞大的计算量。使用动态网格的DSMC方法可以根据流场信息,动态生成自适应... 详细信息

直接模拟蒙特卡罗方法(direct simulation Monte Carlo,DSMC)是稀薄气体动力学领域的重要工具。然而,DSMC方法有两个比较主要的缺点:一是复杂的网格处理;另一个是庞大的计算量。使用动态网格的DSMC方法可以根据流场信息,动态生成自适应的碰撞网格,能有效解决前一个缺点;针对后一个缺点,使用统一计算架构(compute unified device architecture,CUDA)编写并行程序,将基于动态网格的DSMC方法移植到图形处理器(graphic processing unit,GPU)上以减少计算时间。在并行实现中,GPU负责绝大部分的计算,而CPU只负责初始化、结果输出等少量工作。使用一个二维超音速横掠平板问题作为算例,验证了并行程序的正确性。对于不同规模的算例,在NVIDIA Fermi C2050之上均获得了10倍以上的加速比;对于相同算例,NVIDIA最新发布的Kepler K20上的速度约为FermiC2050上的1.3～1.6倍。

关键词：统一计算架构(CUDA) 图形处理器(GPU) 直接模拟蒙特卡罗方法(DSMC) 动态网格DSMC 并行模拟

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Anomalously enhanced thermal stability of phosphorene via metal adatom doping: An experimental and first-principles study

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Nano Research 2016年第9期9卷 2687-2695页

作者： Xuewei Feng Vadym V.Kulish Ping Wu xinke Liu Kah-wee Ang Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Singapore Entropic Interface Group(EIG) Engineering Product DevelopmentSingapore University of Technology and Design(SUTD)8 Somapah RoadSingapore 487372Singapore College of Materials Science and Engineering Shenzhen Engineering Laboratory for Advanced Technology of CeramicsNanshan District Key Lab for Biopolymer and Safety EvaluationShenzhen University3688 Nanhai AvenueShenzhen 518060China

Atomically thin black phosphorus, also known as phosphorene, is an emerging two-dimensional (2D) material, which has attracted increasing attention due to its unique electronic and optoelectronic properties. However, the reduced thermal stability of phosphorene limits its suitability for high-temperature fabrication processes, which could be detrimental for the performance of phosphorenebased devices. Here, we investigate the impact of doping by Al and Hf transition metal adatoms on the thermal stability of phosphorene. The formation of Al–P covalent bonds was found to significantly improve the thermal coefficients of the Ag1, B2g, and Ag2phonon modes to 0.00044, 0.00081, and 0.00012 cm–1·°C–1, respectively, which are two orders of magnitude lower than those observed for pristine P–P bonds (~0.01 cm–1·°C–1). First-principles calculations within the density functional theory framework reveal that the observed thermal stability enhancement in the Al-doped material reflects a significantly higher Al binding energy, due to the stronger Al–P bonds compared to the weak van der Waals interactions between adjacent P atoms in the undoped material. The present work thus paves the way towards phosphorene materials with improved structural stability, which could be promising candidates for potential nanoelectronic and optoelectronic applications. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： phosphorene black phosphorus adatom doping transition metals thermal stability

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Occurrence of microorganic pollutants in the atmosphere of Singapore during haze and non-haze periods

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Chinese Journal Of Geochemistry 2006年第B8期25卷 183-183页

作者： Rajasekhar Balasubramanian Chanbasha Basheer Kang Lisa siao Wei see Division of Environmental Science and Engineering Department of Chemical and Biomolecular Engineering Department of Chemistry

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关於逼近函数类∧~*的一个漸近公式

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南京大学学报(自然科学版) 1959年第3期 1-6页

作者：郑維行

設f（x）∈C2x.根据***的記号,凡滿足条件 |f（x+h）+f（x-h）-2f（x）|≤M|h|的函数f的全体所成的类用∧*表示,这里M为常数。在逼近論的不少問題中,研究类∧*乃是很自然的。 Vallee Poussin曾考虑用与***奇異积分相似的工具

关键词：常数数学二阶差分渐近式

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