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Investigation of the thermal conductivities across metal-insulator transition in polycrystalline VO_2

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Chinese Science Bulletin 2012年第26期57卷 3393-3396页

作者： CHEN JiKun liu XinLing YUAN Xun ZHANG YuLiang GAO YanFeng ZHOU YanFei liu ruiheng CHEN LiDong CHEN NuoFu School of Renewable Energy North China Electric Power UniversityBeijing 102206China CAS Key laboratory of Materlals for Energy Converszon Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China

Previous reports about the thermal conductivities of VO2 showed various temperature dependences across metal-insulator transition (MIT) temperature. In this work, polycrystalline VO2 samples were fabricated by spark plasma sintering of VO2 powder. Temperature dependences of their thermal conductivities were investigated using laser flash technique, and the thermal conductivity showed a significant decrease trend from metal-phase to insulator phase. Electrical transport properties were investigated to confirm both carrier and lattice contribution to the thermal conductivity. It is found that the lattice thermal conductivity decreased significantly across MIT point, which may be caused by soft phonon mode in metal phase of VO2 .

关键词：晶格热导率 VO2 金属相绝缘体多晶放电等离子烧结温度依赖性转变温度

Superior performance and high service stability for Ge Te-based thermoelectric compounds

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National Science Review 2019年第5期6卷 944-954页

作者： Tong Xing Qingfeng Song Pengfei Qiu Qihao Zhang Xugui Xia Jincheng Liao ruiheng liu Hui Huang Jiong Yang Shengqiang Bai Dudi Ren Xun Shi Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Materials Genome Institute Shanghai University

GeTe-based compounds have been intensively studied recently due to their superior thermoelectric performance, but their real applications are still limited so far due to the drastic volume variation that occurs during the rhombohedral–cubic phase transition, which may break the material or the material/electrode interface during ***, superior performance and high service stability for GeTe-based thermoelectric compounds are achieved by co-doping Mg and Sb into *** linear coefficient of thermal expansion before phase transition is greatly improved to match that after phase transition, yielding smooth volume variation around the phase transition ***, co-doping(Mg, Sb) in GeTe successfully tunes the carrier concentration to the optimal range and effectively suppresses the lattice thermal conductivity.A peak z T of 1.84 at 800 K and an average z T of 1.2 in 300–800 K have been achieved in ***, a Ni/Ti/Ge0.85Mg0.05Sb0.1Te thermoelectric uni-leg is fabricated and tested, showing quite good service stability even after 450 thermal cycles between 473 K and 800 *** study will accelerate the application of GeTe-based compounds for power generation in the mid-temperature range.

关键词： thermoelectrics phase transition thermal expansion service stability power generation application

An engineered Cas12i nuclease that is an efficient genome editing tool in animals and plants

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The Innovation 2024年第2期5卷 61-69页

作者： Zhiqiang Duan Yafeng Liang Jialei Sun Hongjin Zheng Tong Lin Pengyu Luo Mengge Wang ruiheng liu Ying Chen Shuhua Guo Nannan Jia Hongtao Xie Meili Zhou Minghui Xia Kaijun Zhao Shuhui Wang Na liu Yongling Jia Wei Si Qitong Chen Yechun Hong Ruilin Tian Jian-Kang Zhu Institute of Advanced Biotechnology and School of Medicine Southern University of Science and TechnologyShenzhen 518055China Bellagen Biotechnology Jinan 250000China Department of Medical Neuroscience School of MedicineKey University Laboratory of Metabolism and Health of GuangdongSouthern University of Science and TechnologyShenzhenGuangdong Province 518055China

The type V-I CRISPR-Cas system is becoming increasingly more attractive for genome ***,natural nucleases of this system often exhibit low efficiency,limiting their ***,we used structure-guided rational design and protein engineering to optimize an uncharacterized Cas12i nuclease,*** a result,we developed Cas-SF01,a Cas12i3 variant that exhibits significantly improved gene editing activity in mammalian ***-SF01 shows comparable or superior editing performance compared to SpCas9 and other Cas12 *** to natural Cas12i3,Cas-SF01 has an expanded PAM range and effectively recognizes NTTN and noncanonical NATN and TTVN *** addition,we identified an amino acid substitution,D876R,that markedly reduced the off-target effect while maintaining high on-target activity,leading to the development of CasSF01^(HiFi)(high-fidelity Cas-SF01).Finally,we show that Cas-SF01 has high gene editing activities in mice and *** results suggest that CasSF01 can serve as a robust gene editing platform with high efficiency and specificity for genome editing applications in various organisms.

关键词： system attractive rational

Copper chalcogenide thermoelectric materials

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Science China Materials 2019年第1期62卷 8-24页

作者： Tian-Ran Wei Yuting Qin Tingting Deng Qingfeng Song Binbin Jiang ruiheng liu Pengfei Qiu Xun Shi Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences University of Chinese Academy of Sciences

Cu-based chalcogenides have received increasing attention as promising thermoelectric materials due to their high efficiency,tunable transport properties,high elemental abundance and low *** this review,we summarize the recent research progress on this large family compounds covering diamond-like chalcogenides and liquid-like Cu2X (X=S,Se,Te)binary compounds as well as their multinary *** materials have the general features of two sublattices to decouple electron and phonon transport *** the one hand,the complex crystal structure and the disordered or even liquid-like sublattice bring about an intrinsically low lattice thermal *** the other hand, the rigid sublattice constitutes the charge-transport network, maintaining a decent electrical *** specific material systems,we demonstrate their unique structural features and outline the structure-performance correlation. Various design strategies including doping,alloying,band engineering and nanostructure architecture,covering nearly all the material scale,are also ***,the potential of the application of Cu-based chalcogenides as high-performance thermoelectric materials is briefly discussed from material design to device development.

关键词： thermoelectric Cu-based chalcogenides sublattice transport properties

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大规模地形渲染技术的研究与实现

西北工业大学学报 2010年第6期28卷 936-940页

作者：邓正宏张婷婷刘瑞恒张怡西北工业大学自动化学院陕西西安710072

文章针对大规模地形渲染中显示质量和显示速度之间的矛盾问题,采用基于四叉树的LOD技术,在地形简化的评价系统中考虑距离标准与地形粗糙度基础上,增加考虑运动矢量与观察矢量以完成大规模地形的网格构造,同时结合雷达视锥体剔除法,提高... 详细信息

文章针对大规模地形渲染中显示质量和显示速度之间的矛盾问题,采用基于四叉树的LOD技术,在地形简化的评价系统中考虑距离标准与地形粗糙度基础上,增加考虑运动矢量与观察矢量以完成大规模地形的网格构造,同时结合雷达视锥体剔除法,提高渲染速率,并综合受约束的四叉树消除裂缝,实现大规模地形实时渲染。实验结果表明该系统在基本保证场景的真实性前提下,较快地实现大规模地形的渲染,取得较好的渲染效果。

关键词：大规模地形渲染四叉树细节层次评价系统裂缝消除

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基于语言模型的预训练技术研究综述

中文信息学报 2021年第9期35卷 15-29页

作者：岳增营叶霞刘睿珩火箭军工程大学作战保障学院陕西西安710025

预训练技术当前在自然语言处理领域占有举足轻重的位置。尤其近两年提出的ELMo、GTP、BERT、XLNet、T5、GTP-3等预训练模型的成功,进一步将预训练技术推向了研究高潮。该文从语言模型、特征抽取器、上下文表征、词表征四个方面对现存的... 详细信息

预训练技术当前在自然语言处理领域占有举足轻重的位置。尤其近两年提出的ELMo、GTP、BERT、XLNet、T5、GTP-3等预训练模型的成功,进一步将预训练技术推向了研究高潮。该文从语言模型、特征抽取器、上下文表征、词表征四个方面对现存的主要预训练技术进行了分析和分类,并分析了当前自然语言处理中的预训练技术面临的主要问题和发展趋势。

关键词：自然语言处理预训练语言模型

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面向自然语言处理任务的预训练模型综述

计算机应用 2021年第5期41卷 1236-1246页

作者：刘睿珩叶霞岳增营火箭军工程大学作战保障学院西安710025

近年来,深度学习技术得到了快速发展。在自然语言处理(NLP)任务中,随着文本表征技术从词级上升到了文档级,利用大规模语料库进行无监督预训练的方式已被证明能够有效提高模型在下游任务中的性能。首先,根据文本特征提取技术的发展,从词... 详细信息

近年来,深度学习技术得到了快速发展。在自然语言处理(NLP)任务中,随着文本表征技术从词级上升到了文档级,利用大规模语料库进行无监督预训练的方式已被证明能够有效提高模型在下游任务中的性能。首先,根据文本特征提取技术的发展,从词级和文档级对典型的模型进行了分析;其次,从预训练目标任务和下游应用两个阶段,分析了当前预训练模型的研究现状,并对代表性的模型特点进行了梳理和归纳;最后,总结了当前预训练模型发展所面临的主要挑战并提出了对未来的展望。

关键词：自然语言处理预训练模型深度学习无监督学习神经网络

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井下刮板转载机的优化改造

机械管理开发 2019年第3期34卷 267-268,275页

作者：刘瑞恒山西平舒煤业有限公司山西晋中045413

在煤矿井下的现场应用中,刮板转载机由于其存在结构上的缺陷和维修技术上的问题,往往会发生故障,这严重影响了煤炭的正常输送,为解决这一问题,提高煤矿企业的经济效益,对刮板转载机进行了相应的优化改造,针对转载机的挡煤板、中部槽、... 详细信息

在煤矿井下的现场应用中,刮板转载机由于其存在结构上的缺陷和维修技术上的问题,往往会发生故障,这严重影响了煤炭的正常输送,为解决这一问题,提高煤矿企业的经济效益,对刮板转载机进行了相应的优化改造,针对转载机的挡煤板、中部槽、电缆架、抬升装置以及维修技术等进行改进设计。经过上述优化改造后的刮板转载机,不仅提高了运行效率,还实现了煤矿井下的安全高效生产。

关键词：刮板转载机结构改进挡煤板抬升装置

外源花青素对干旱胁迫下烤烟幼苗生长及其生理特性的影响

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干旱地区农业研究 2022年第6期40卷 63-71页

作者：庄晔刘瑞恒付国占王小东河南科技大学农学院/河南省旱地农业工程技术研究中心河南洛阳471023

以烤烟品种‘秦烟96’和‘云烟116’等2个烤烟品种为试验材料,通过开展盆栽试验,设置正常供水和中度干旱等2个水分梯度,外源花青素设置6个浓度,研究外源花青素对干旱胁迫下烤烟幼苗农艺性状、单株干重、光合气体参数、叶绿素荧光参数及... 详细信息

以烤烟品种‘秦烟96’和‘云烟116’等2个烤烟品种为试验材料,通过开展盆栽试验,设置正常供水和中度干旱等2个水分梯度,外源花青素设置6个浓度,研究外源花青素对干旱胁迫下烤烟幼苗农艺性状、单株干重、光合气体参数、叶绿素荧光参数及活性氧代谢系统的影响。结果表明:干旱胁迫下,两个烤烟品种生长受到抑制且生理性能下降;干旱胁迫下喷施外源花青素可显著增加烤烟幼苗的株高、茎围、最大叶长、最大叶宽、最大叶面积、单株干重、净光合速率、气孔导度、蒸腾速率PSⅡ最大光化学效率、PSⅡ实际光化学效率和光化学猝灭系数,降低叶片中胞间CO_(2)浓度和非光化学猝灭系数,降低超氧阴离子自由基产生速率和丙二醛含量,提高叶片中超氧化物歧化酶、过氧化物酶和过氧化氢酶活性,增强烤烟幼苗对干旱胁迫的耐受性,有效缓解干旱胁迫对烤烟幼苗生长及其生理功能的损害;其中‘秦烟96’以叶面喷施3 mg·L^(-1)花青素对考烟幼苗生长的促进效果最佳,‘云烟116’以叶面喷施4 mg·L^(-1)花青素效果最佳。

关键词：烤烟干旱胁迫花青素农艺性状生理特性