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Strengthening effect of Cu-rich phase precipitation in 18Cr9Ni3CuNbN austenitic heat-resisting steel

Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 141-147页

作者： Chengyu chi Hongyao YU Jianxin DONG Xishan XIE Zhengqiang CUI Xiaofang CHEN Fusheng lin High Temperature Materials Research Laboratories School of Materials Science and EngineeringUniversity of Science and Technology Beijing Beijing 100083 China Shanghai Power Equipment Research Institute Shanghai 200240 China

The Cu-containing austenitic heat-resistant steel 18Cr9Ni3CuNbN, which is being used as superheater and reheater tube material for modern ultra-super-critical （USC） power plants all over the world, has been investigated at 650 ℃ long time aging till 10 000 h. SEM, TEM and 3DAP （three dimensional atom probe） have been used to follow microstructural changes with mechanical property variations. Experimental results show that Cu-rich phase and MX precipitate in the grains as well as M 23 C 6 precipitates at grain boundaries are the main precipitation strengthening phases in this steel. Among them Cu-rich phase is the most important strengthening phase. Homogeneous distribution of very fine nano-size Cu-rich phase has been formed at very early stage of 650 ℃ aging （less than 1 h）. Cu atoms gradually concentrate to Cu-rich particles and the other elements （such as Fe, Cr, Ni etc） diffuse away from Curich particles to γ-matrix with the increasing of aging time at 650 ？ C. The growth rate of Cu-rich phase at 650 ℃ long time aging is very slow and the average diameters of Cu-rich phase have been determined by TEM method. Cu-rich phase keeps in about 30 nm till 650 ℃ aging for 10 000 h. It shows that nano-size Cu-rich phase precipitation strengthening can be kept for long time aging at 650 ℃ because of its excellent stability at high temperatures. According to structure stability study and mechanical properties determination results the Cu-rich phase precipitation sequence and its strengthening mechanism model have been suggested and discussed.

关键词： Austenitic heat-resistant steel Precipitation strengthening Cu-rich phase MX M 23 C 6

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Comparative investigation of coal-and oil-fired boilers based on emission factors,ozone and secondary organic aerosol formation potentials of VOCs

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Journal of Environmental Sciences 2020年第6期32卷 245-255页

作者： Hsi-Hsien Yang Sunil Kumar Gupta Narayan Babu Dhital lin-chi Wang Suresh Pandian Elumalai Department of Environmental Engineering and Management Chaoyang University of TechnologyTaichungChinese Taipei Department of Applied Chemistry Chaoyang University of TechnologyTaichungChinese Taipei Department of Environmental Science Patan Multiple CampusTribhuvan UniversityLalitpurNepal Department of Environmental Engineering Chung Yuan Christian UniversityTaoyuanChinese Taipei Department of Environmental Science and Engineering Indian Institute of Technology(Indian School of Mines)DhanbadIndia

Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate *** this study,VOC emission factors,O3 and SOA formation potentials were estimated for two types of industrial boilers:coal-fired boilers(n=3)and oil-fired boilers(n=3).Results showed that EVOCs concentrations were more than nine times higher for oil-fire d boilers compared to those for coal-fired *** factors ofΣVOCs were found to be higher for oil-fired boilers(9.26-32.83 mg-VOC/kg)than for coal-fired boilers(1.57-4.13 mg-VOC/kg).Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers,while oxygenated organics and aromatics were the most contributing groups in oil-fired ***,n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions,whereas toluene was the most abundant VOC species emitted from oil-fired boilers.O3 and SOA formation potentials were found 12 and 18 times,respectively,higher for oil-fired than for coal-fired *** OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired *** oil-fired boilers,total OFP ranged from 36.16 to 131.93 mg-O3/***,total secondary organic aerosol potential(SOAP)ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers,respectively.

关键词： Coal-and oil-fired boilers Volatile organic compounds Emission factor Ozone formation potential Secondary organic aerosol potential

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Tsinghua Science and Technology 2020年第5期25卷 604-613页

作者： Jinchang Hu Jinfu Chen lin Zhang Yisong Liu Qihao Bao Hilary Ackah-Arthur chi Zhang the School of Computer Science and Communication Engineering Jiangsu UniversityZhenjiang 212013China

Developing secure software systems is a major challenge in the software industry due to errors or weaknesses that bring vulnerabilities to the software *** address this challenge,researchers often use the source code features of vulnerabilities to improve vulnerability *** the success achieved by these techniques,the existing studies mainly focus on the conceptual description without an accurate definition of vulnerability *** this study,we introduce a novel and efficient Memory-Related Vulnerability Detection Approach using Vulnerability Features (MRVDAVF).Our framework uses three distinct strategies to improve vulnerability *** the first stage,we introduce an improved Control Flow Graph (CFG) and Pointer-related Control Flow Graph (PCFG) to describe the features of some common vulnerabilities,including memory leak,doublefree,and ***,two algorithms,namely Vulnerability Judging algorithm based on Vulnerability Feature (VJVF) and Feature Judging (FJ) algorithm,are employed to detect memory-related ***,the proposed model is validated using three test cases obtained from Juliet Test *** experimental results show that the proposed approach is feasible and effective.

关键词： vulnerability feature Control Flow Graph(CFG) Memory Leak(ML) Double-Free(DF) Use-After-Free(UAF)

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Environmental risk assessment of selected organic chemicals based on TOC test and QSAR estimation models

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Journal of Environmental Sciences 2018年第2期30卷 23-31页

作者： Yulang chi Huanteng Zhang Qiansheng Huang Yi lin Guozhu Ye Huimin Zhu Sijun Dong Key Lab of Urban Environment and Health Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China College of Resources and Environment University of Chinese Academy of Sciences Beijing 100049 China

Environmental risks of organic chemicals have been greatly determined by their persistence,bioaccumulation, and toxicity（PBT） and physicochemical properties. Major regulations in different countries and regions identify chemicals according to their bioconcentration factor（BCF） and octanol–water partition coefficient（Kow）, which frequently displays a substantial correlation with the sediment sorption coefficient（Koc）. Half-life or degradability is crucial for the persistence evaluation of chemicals. Quantitative structure activity relationship（QSAR） estimation models are indispensable for predicting environmental fate and health effects in the absence of field-or laboratory-based data. In this study, 39 chemicals of high concern were chosen for half-life testing based on total organic carbon（TOC） degradation,and two widely accepted and highly used QSAR estimation models（i.e., EPI Suite and PBT Profiler） were adopted for environmental risk evaluation. The experimental results and estimated data, as well as the two model-based results were compared, based on the water solubility, Kow, Koc, BCF and half-life. Environmental risk assessment of the selected compounds was achieved by combining experimental data and estimation models. It was concluded that both EPI Suite and PBT Profiler were fairly accurate in measuring the physicochemical properties and degradation half-lives for water, soil, and ***, the half-lives between the experimental and the estimated results were still not absolutely consistent. This suggests deficiencies of the prediction models in some ways, and the necessity to combine the experimental data and predicted results for the evaluation of environmental fate and risks of pollutants.

关键词： QSAR Risk assessment Predictive toxicology TOC Physicochemical property

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A conserved inverted repeat from rice plastome functions as an intrinsic transcription terminator

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chinese Science Bulletin 2005年第15期50卷 1669-1672页

作者： lin chi-Hui LIANG Yu-din CHEN Liang-Jwu Institute of Molecular Biology National Chung-Hsing UniversityTaichung 402 Taiwan China Institute of Chemistry Academia Sinica Taipei 115 Taiwan China

Results from a previous rice transcription mapping and the GeSTer algorithm analysis used in this in-vestigation for rice plastid genome suggest that an inverted repeat, IRs18, in 3′ region of the plastid rps18 gene may serve as a transcription terminator. The in vitro transcription assay showed that the transcript ending at the IRs18 was not proc-essed by ribonucleases but terminated intrinsically in an rNTP substrate-dependent manner as demonstrated for the first time in plant gene regulation. For the poly-T tract (TTCTTTTTT) 3′-proximal to the IRs18, the C base conver-sion to T resulting in a perfect 9 Ts can dramatically increase termination efficiency, which is a common feature of bacte-rial intrinsic termination. This study is the first case to indi-cate that a conserved inverted repeat with a poly-T tract from higher plant chloroplast contributes to transcription termination of the translation-associated rps18 gene in a manner with the intrinsic termination, probably resulting from a heritage of endosymbiosis.

关键词：水稻叶绿体转录基因反向重复质体基因组

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Bandgap prediction by deep learning in configurationally hybridized graphene and boron nitride

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npj Computational Materials 2019年第1期5卷 915-922页

作者： Yuan Dong Chuhan Wu chi Zhang Yingda Liu Jianlin Cheng Jian lin Department of Mechanical&Aerospace Engineering University of MissouriColumbiaMO 65211USA Department of Electrical Engineering&Computer Science University of MissouriColumbiaMO 65211USA

It is well-known that the atomic-scale and nano-scale configuration of dopants can play a crucial role in determining the electronic properties of ***,predicting such effects is challenging due to the large range of atomic configurations that are ***,we present a case study of how deep learning algorithms can enable bandgap prediction in hybridized boron–nitrogen graphene with arbitrary supercell configurations.A material descriptor that enables correlation of structure and bandgap was developed for convolutional neural *** calculated by ab initio calculations,and corresponding structures,were used as training *** trained networks were then used to predict bandgaps of systems with various *** 4×4 and 5×5 supercells they accurately predict bandgaps,with a R^(2) of >90% and root-mean-square error of~0.1 *** transfer learning was performed by leveraging data generated from small supercells to improve the prediction accuracy for 6×6 *** work will pave a route to future investigation of configurationally hybridized graphene and other 2D ***,given the ubiquitous existence of configurations in materials,this work may stimulate interest in applying deep learning algorithms for the configurational design of materials across different length scales.

关键词： materials configuration boron

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Thermoacoustic tomography of in vivo rat brain

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Journal of Innovative Optical Health Sciences 2017年第4期10卷 84-90页

作者： Yuan Zhao Zihui chi lin Huang Zhu Zheng Jinge Yang Huabei Jiang School of Physical Electronics University of Electronic Science and Technology of china No.2006 Xiyuan AveWest Hi-Tech Zone ChengduSichuan 611731P.R.China Department of Medical Engineering University of South Florida Tampa FL 33620USA Center for Information in Medicine University of Electronic Science and Technology of china No.2006 Xiyuan AveWest Hi-Tech Zone ChengduSichuan 611731P.R.China

We present for the¯rst time in vivo imaging of rat brain using microwave-induced thermoacoustic tomography(TAT).The in vivo imaging of rat brain was realized through an unconventional delivery of microwave energy from the front of rat brain(while the transducer was scanned along coronal plane of the animal brain),which maximized the microwave penetration into the *** addition,we found that the imaging contrast was highly dependent on the direction of the electric¯eld polarization(EFP)and that more tissue structures/compositions could be revealed when both X-and Y-EFPs were used for *** in vivo TAT images of rat brain obtained were compared with the 3.0 T MRI images and histological photographs,and numerous important brain anatomical structures were identi¯*** example of our TAT approach for imaging a foreign object embedded in a rat brain was also *** study suggests that TAT has a great potential to be used in neuroscience studies and in noninvasive imaging of brain disorders.

关键词： Thermoacoustic imaging tomography rat brain

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SINGULAR PERTURBATION OF BOUNDARY VALUE PROBLEM OF SYSTEMS FOR QUASIlinEAR ORDINARY DIFFERENTIAL EQUAT1ONS

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Applied Mathematics and Mechanics(English Edition) 1990年第11期11卷 1035-1042页

作者： lin Zong-chi lin Su-rong Fujian Normal liniversils Fuzhou Fijian Broadcasting TV University Fuzhou

In this paper,we study the singular perturbation of boundary value problem of systems for quasilinear ordinary differential equations:x'=j(i,x,y,ε),εy'=g(t,x,y,ε)y'+h(t,x,y,ε),y(0,ε)=A(ε),y(0,ε)=B(ε),y(1,ε)=C(ε)where xf.y,h,A,B and C belong to Rn and a is a diagonal *** the appropriate assumptions,using the technique of diagonalization and the theory of differential inequalities we obtain the existence of solution and its componentwise uniformly valid asymptotic estimation.

关键词： Quasilinear systems Singularly perturbed boundary value problem,Diagonalization and differential inequality Asymptotic expansion.

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An Adaptive Bandwidth Allocation for Energy Efficient Wireless Communication Systems

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Journal of Electronic Science and Technology 2015年第1期13卷 27-32页

作者： Yung-Fa Huang Che-Hao Li Chuan-Bi lin chia-chi Chang Department of Information and Communication Engineering Chaoyang University of Technology

In this paper, an energy efficient bandwidth allocation scheme is proposed for wireless communication systems. An optimal bandwidth expansion（OBE） scheme is proposed to assign the available system bandwidth for users. When the system bandwidth does not reach the full load, the remaining bandwidth can be energy-efficiently assigned to the other users. Simulation results show that the energy efficiency of the proposed OBE scheme outperforms the traditional same bandwidth expansion（SBE） scheme. Thus, the proposed OBE can effectively assign the system bandwidth and improve energy efficiency.

关键词： Bandwidth resource allocation energy efficiency optimal bandwidth expansion same bandwidth expansion

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Bank Reforms, Competition and Efficiency in china's Banking System: Are Small City Bank Entrants More Efficient?

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china & World Economy 2009年第5期17卷 69-87页

作者： Hui-lin lin chia-chi Tsao chih-Hai Yang Department of Economics National Taiwan University Department of Economics National Central University

This paper analyzes technical efficiency in china＇s banking system by large banks and small city banks as well as the pre-WTO and post-WTO accession periods＇. Using an unbalanced panel dataset for 63 banks over 1997-2006 and employing the stochastic frontier function approach, the empirical results reveal that the new entrants, small city banks, experienced a slightly higher efficiency score than incumbent large banks, on average. Compared with the pre- WTO accession period, the efficiency score is found to have improved significantly after entry into the WTO as a result of the competition effect. This competition effect is particularly relevant for small city banks. Finally, determinants of X-inefficiency are examined

关键词： bank reform competition efficiency small bank

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