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Effects of growth temperature on μc-Si:H films prepared by plasma assistant magnetron sputtering

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Rare Metals 2012年第2期31卷 193-197页

作者： Su, yuanjun dond, Chuang Zhu, Ming Xu, Jun Fan, Penghui Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology Dalian 116024 China Nissin Electric-dalian University of Technology Joint R&d Center Dalian University of Technology Dalian 116024 China

Hydrogenated microcrystalline silicon thin films (μc-Si:H) were deposited by plasma assistant magnetron sputtering in Ar-H 2 gas mixture. The effects of growth temperature from 150 to 450 C on properties of deposited Si films were investigated at two different hydrogen diluted gases with [H 2 ]/([Ar]+[H 2 ]) of 10% and 50% at 3 Pa. The crystallinity of Si films examined by Raman scattering exhibited higher degrada- tion by lowering growth temperature from 250 to 150 C in low hydrogen diluted gas of 10% than that in high hydrogen diluted gas of 50%. The IR absorption band around 845 and 890 cm 1 as well as calculated concentration of bonded hydrogen showed more obvious decrease of samples deposited in low hydrogen diluted gas of 10% than that in high hydrogen diluted gas of 50%. The optical band gasps of both groups of samples measured by ultraviolet-visible optical absorption were decreased with increasing temperature in both gas conditions.

关键词： microcrystalline silicon Raman scattering hydrogen-silicon bond.ng optical band gap

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Geometric effects of fuel regression rate in hybrid rocket motors

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Science China(Technological Sciences) 2016年第5期59卷 807-813页

作者： CAI GuoBiao ZHAng yuanjun WAng PengFei HUI Tian ZHAO Sheng YU NanJia School of Astronautics Beihang University Beijing 100191 China Beijing Institute of Aerospace Systems Engineering Beijing 100076 China

The geometric configuration of the solid fuel is a key parameter affecting the fuel regression rate in hybrid rocket motors. In this paper, a semi-empirical regression rate model is developed to investigate the geometric effect on the fuel regression rate by incorporating the hydraulic diameter into the classical model. The semi-empirical model indicates that the fuel regression rate decreases with increasing hydraulic diameter and is proportional to dh?0.2 when convective heat transfer is dominant. Then a numerical model considering turbulence, combustion, solid fuel pyrolysis, and a solid–gas coupling model is established to further investigate the geometric effect. Eight motors with different solid fuel grains are simulated, and four methods of scaling the regression rate between different solid fuel grains are compared. The results indicate that the solid fuel regression rates are approximate the same when the hydraulic diameters are equal. The numerical results verify the accuracy of the semi-empirical model.

关键词： geometric effect regression rate hydraulic diameter hybrid rocket motor

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Model maturity towards modeling and simulation:Concepts,index system framework and evaluation method

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第3期11卷 1-21页

作者： Lin Zhang Ying Liu yuanjun Laili Weicun Zhang School of Automation Science and Electrical Engineering Beihang University(BUAA) Engineering Research Center of Complex Product Advanced Manufacturing Systems Ministry of EducationBeijing Advanced Innovation Center for Big Data-Based Precision Medicine Beijing 100191P.R.China School of Automation and Electrical Engineering University of Science and Technology Beijing Beijing 100083 P.R.China

Simulation has become an essential way and sometimes the only way to study complex systems(e.g.,system of systems,SoS).Simulation is the model-based *** to build a high-quality model is the first consideration in *** and credibility are the two mostly used metrics to evaluate the quality of a ***,the definitions and evaluation methods of fidelity and credibility vary from one research to another and it’s hard to evaluate the metrics *** importantly,the evolution process of a model in use cannot be directly reflected by the two ***,this paper introduces the model maturity to track the status of a model during its life cycle,especially in the use and management phases,which will be an important supplement to the quality evaluation system of *** concept of model maturity is given and a framework of index system for model maturity evaluation is ***,a hierarchical evaluation method based on qualitative and quantitative analysis(HEQQ)for model maturity is ***,a case study is used to validate the feasibility and effectiveness of the proposed method.

关键词： Modeling and simulation(M&S) model maturity index system evaluation method

Symbolism in James Joyce's Short Stories

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Symbolism in James Joyce's Short Stories

作者： Qi yuanjun 西安外国语大学

学位级别：硕士

本研究题目的选择是基于象征主义手法在乔伊斯早期文学创作中的重要性。《都柏林人》是乔伊斯早期文学创作的代表作。除了《死者》，剩下的三篇短篇故事－《会议室的常青藤日》、《母亲》和《圣恩》都被国内学者研究的较少。本文主要从... 详细信息

本研究题目的选择是基于象征主义手法在乔伊斯早期文学创作中的重要性。《都柏林人》是乔伊斯早期文学创作的代表作。除了《死者》，剩下的三篇短篇故事－《会议室的常青藤日》、《母亲》和《圣恩》都被国内学者研究的较少。本文主要从物品象征、背景象征和人物象征三方面分析研究以上四篇短篇故事。大多数的物品都是老旧的。几乎所有的背景设定都是阴暗的。许多人物要不就是老去的，要不就是已经去世的。这些人物的生活方式也都是堕落的。研究结果表明，通过象征主义的运用，乔伊斯成功的强化了《都柏林人》的主题－堕落。乔伊斯匠心独运的选择了小件的物品、设定了阴郁的背景、并且描绘了都柏林人腐败的生活方式来体现都柏林的堕落。

关键词：乔伊斯象征主义短篇小说《都柏林人》

XdEVS: A hybrid system modeling framework

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第2期13卷 233-249页

作者： Kunyu Xie Lin Zhang yuanjun Laili Xiaohan Wang School of Automation Science and Electrical Engineering Engineering Research Center of Complex Product Advanced Manufacturing Systems Ministry of Education Beihang University No.37Xueyuan RoadBeijingChina

When discrete Event System Specification(dEVS)is used as a modeling tool,there is a semantic gap between a dEVS model and the mathematical representation,which may result in understand.ng *** provide a more intuitive form of modeling,XdEVS expands the concept of states in *** continuous state is introduced in XdEVS,which enhances the ability to model hybrid *** on the dEVS simulation framework,a simulation engine is developed to drive the XdEVS model safely and efficiently and avoid the wrong location of state events during the simulation of the continuous model.A hybrid model is constructed and simulated using XdEVS.A comparison between the XdEVS model and models described by dEV&dESS and GdEVS shows that XdEVS can clearly express the structure of the model and reduce the burden on modelers.

关键词： dEVS XdEVS hybrid model modeling framework

Full sexual maturity-cycle exposure to environmentally relevant concentrations of 17β-estradiol decreases reproductive capacity of zebrafish

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Journal of Environmental Sciences 2024年第3期137卷 580-592页

作者： Yongkang Zhang yuanjun Jiang Qian Sun Meng Li Sheng Chen Jingyu Liang Chunsheng Liu College of Fisheries Huazhong Agricultural UniversityWuhan 430070China School of Environmental Studies China University of GeosciencesWuhan 430074China

17β-Estradiol(E2)has been widely detected in natural water and treatment with E2 induces potential endocrine disrupting effects in ***,effects on fish fecundity and steroid system after treatment with environmentally relevant concentrations of E2 for the full sexual maturation cycle remain *** this study,zebrafish were treatment with 0,10 or100 ng/L E2 from embryo to adult stage,and effects on gonadal development and differentiation,steroid hormone levels,transcription of genes associated with the hypothalamic-pituitary-gonadal-liver(HPG)axis in adults and fertilization rate of offspring were *** results showed that treatment with E2 lead to increased number of feminization in *** females,E2 decreased cumulative amount of spawning and inhibited the maturation of *** males,E2 inhibited the maturation and motility of sperm,as well as decreased the movement speed of *** adverse effects on sperm might be responsible for the reduced fertilization observed in *** addition,treatment with E2 changed the levels of steroid hormones in zebrafish gonad and altered the transcriptional levels of genes associated with HPG axis,which is responsible for the regulation of germ cells maturation and gonadal development in ***,these results suggested that treatment with environmentally relevant concentrations of E2 for the full sexual maturity cycle resulted in adverse effects on reproduction in zebrafish.

关键词： Environmental estrogen Zebrafish Fecundity Gonadal development Endocrine disruption

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Environmental consequences of an ultra-low emission retrofit in coal-fired power plants from a life cycle perspective

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Waste disposal and Sustainable Energy 2021年第4期3卷 309-323页

作者： Jun d.ng yuanjun Tang Aizhong Ruan Jie Chen Xiaoqing Lin Shengyong Lu Xiang Gao State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China Zhejiang Energy R&d Institute Co. Ltd.Hangzhou 311121China Key Laboratory of Energy Conservation and Pollutant Control Technology for Thermal Power of Zhejiang Province Hangzhou 311121China department of Energy and Environment System Engineering Zhejiang University of Science and TechnologyHangzhou 310023China Zhejiang Shengyuan Environmental Testing Technology Co. Ltd.Shaoxing 311899China

To make coal-fired power generation more environmentally friendly,China has initiated a series of ultra-low emission ret-rofits to the air pollution control(APC)system of the existing power *** this study,a life cycle assessment(LCA)is conducted to analyze the environmental net benefits for the typical ultra-low emission retrofit of a 1000 MW power *** key processes,substances,and APC devices are verified and *** results confirm that the retrofit effectively decreases the environmental stress of acidification potential(AP),eutrophication potential(EP),and photochemical ozone creation potential(POCP)by 69%-79%,which can be attributed to significantly reduced emissions at the ***,the retrofit has also increased other impact categories by 24%-79%,primarily due to the consumption of additional elec-tricity and *** retrofit of selective catalytic reduction,electrostatic precipitator(ESP),and wet limestone flue gas desulfurization devices has a dominant effect on the impacts of EP,human toxicity potential(HTP),and AP.A newly installed wet ESP shows some environmental benefits(only for AP),but causes considerable burdens,in particular for the investigated impact categories global warming potential(GWP),marine aquatic ecotoxicity(MAETP),and abiotic depletion fossil(AdP fossil).The obtained results indicate that the hidden environmental consequences,which are associated with the production of energy and materials,need to be examined more comprehensively to inform the development of ultra-low emission technologies and strategies effectively.

关键词： Ultra-low emission retrofit Life cycle assessment Air pollution control system Coal-fired power plants Environmental impacts

Zephyranthes-like Co2NiSe4 arrays grown on 3d porous carbon frame-work as electrodes for advanced supercapacitors and sodium-ion batteries

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Nano Research 2021年第10期14卷 3598-3607页

作者： Yanchun Xue Xingmei Guo Mengrong Wu Jiale Chen Mengting duan Jing Shi Junhao Zhang Fu Cao yuanjun Liu Qinghong Kong School of Environmental and Chemical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of the Environment and Safety Engineering Jiangsu UniversityZhenjiang 212013China

developing suitable electrode materials for electrochemical energy storage devices by biomorph assisted design has become a fascinating topic due to the fantastic properties derived from ***,zephyranthes-like Co_(2)NiSe_(4)arrays grown on butterfly wings derived three-dimensional(3d)carbon framework(Z-Co_(2)NiSe_(4)/BWC)is fabricated via hydrothermal assembly and further conversion *** from its unique structure and multi-components,the obtained Z-Co_(2)NiSe_(4)/BWC electrode for supercapacitor delivers an excellent specific capacitance of 2,280 F·g^(-1)at 1 A·g^(-1).Impressively,the constructed asymmetric supercapacitor using Co_(2)NiSe_(4)/BWC as positive electrode and activated butterfly wings carbon as negative electrode acquires a high energy density of 42.9 Wh·kg^(-1)at a power density of 800 W·kg^(-1)with robust stability of 94.6%capacitance retention at 10 A·g^(-1)after 5,000 ***,the Z-Co_(2)NiSe_(4)/BWC as anode for sodium-ion batteries exhibits a high specific capacity of 568 mAh·g^(-1)at 0.1 A·g^(-1)and high cycling stability(maintaining 80.1%of the second cycle after 100 cycles).The outstand.ng electrochemical performances are ascribed to that the synergistic effect of bimetallic selenides and N-doped carbon improves electrochemical activities and ***-dimensional(1d)nanoneedles grown on 3d porous framework increase the exposure of redox-active sites,endow adequate transmission channels of electrons/ions,and guarantee stability of the electrode during charge/discharge *** study will shed light on the avenue towards extend.ng such nanohybrids to excellent energy storage applications.

关键词： Co_(2)NiSe_(4) three-dimensional(3d)carbon framework synergistic effect supercapacitors sodium-ion batteries

The relationship between the oil shale density and the structural features of correspond.ng kerogens

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Carbon Resources Conversion 2022年第1期5卷 84-91页

作者： Qian Wang Congfei Yao Yuanyuan Zhou yuanjun Che Hongchen Liu Xiaosheng Zhao Yumeng Zhang Xi’an Key Laboratory of Textile Chemical Engineering Auxiliaries School of Environmental and Chemical EngineeringXi’an Polytechnic UniversityXi’an 710000China Institute of Bismuth Science School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China College of Chemistry and Chemical Engineering Cangzhou Normal UniversityCangzhou 061001China

Based on the difference in the density and content of kerogen and inorganic minerals, oil shale can be separatedinto different density fractions. The structural features of kerogens in Beipiao oil shale (a kind of typical lowgrade oil shale resources) with densities of 1.8–1.9, 1.9–2.0 and 2.0–2.1 g/cm3 were studied. Combined withour previous study on the structural features of Longkou and Huadian oil shales (two kinds of high-grade oil shaleresources) with different densities, the relationship between the oil shale density and the structural features ofcorrespond.ng kerogens was revealed from aromatic, aliphatic structures and heteroatom species. The resultsshow that with increasing the density, the content of minerals increases, whereas that of kerogen decreases. Withincreasing the density, the aliphaticity, average methylene chain length and average number of attachments oneach aromatic ring increase. Whereas, the aromaticity and average size of aromatic cluster are inversely proportional to the oil shale density. For Longkou, Huadian and Beipiao oil shales with different densities, thechange rules of aromatic and aliphatic structures with the density are similar, indicating that these change rulesare independent of the grade and origin of oil shale. The change rules of heteroatom species in Beipiao oil shaleare different from that of Longkou and Huadian oil shales.

关键词： Oil shale density Kerogens Structural features