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Laser-assisted Stark deceleration of CaF in its rovibronic ground (high-field-seeking) state
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作者 顾跃凤 陈凯 +1 位作者 黄云霞 杨晓华 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第4期170-176,共7页
A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely... A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely owing to the optical Stark effect. Simulations suggest that the present scheme is superior to previous Stark decelerators. Under typical experimental conditions, when the assisting laser frequency is red-detuned to the molecular transition(λ~606.3 nm) by5.0 GHz and the laser power is about 5.6 W, the proposed decelerator can achieve a total number at the order of 104 CaF molecules with a number density at the order of 10^8 cm^-3. The equivalent temperature of the obtained cold CaF molecules is 2.3 mK. Additionally, the desired assisting laser power can be as low as about 1.2 W if keeping the red-detuning value to be 1.0 GHz, which further suggests its experimental feasibility. 展开更多
关键词 STARK DECELERATION polar MOLECULE optical STARK effect high-field-seeking STATE
The c-axis complex permittivity and electrical impedance in BaFe2As2:Experimental examination on transformation validity
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作者 李永强 杜新哲 +8 位作者 龚冬良 杨綦睿 张汶良 谢涛 冯波 陈恺 罗会仟 刘俊明 朱劲松 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期323-326,共4页
Complex permittivity and electrical impedance have been measured along the c-axis in single crystals BaFe2As2,which are the conductors known as the parent compound of 122-type iron superconductor.The resultant relativ... Complex permittivity and electrical impedance have been measured along the c-axis in single crystals BaFe2As2,which are the conductors known as the parent compound of 122-type iron superconductor.The resultant relative errors defined in the study indicate the existence of the transformation between complex permittivity and electrical impedance in the conductors,and these two physics quantities possibly reveal different aspects of the consistent superconductivityrelevant physics picture. 展开更多
关键词 complex PERMITTIVITY electrical IMPEDANCE BaFe2As2 TRANSFORMATION validity
基于深度卷积网络与尺度不变特征变换的行人跟踪框架 被引量:1
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作者 陈凯 宋晓 刘敬 《中国科学:信息科学》 CSCD 北大核心 2018年第7期841-855,共15页
在计算机视觉领域已经提出了很多物体跟踪算法和多人跟踪算法,但是遮挡一直是跟踪领域一个具有较大挑战性的问题.为了实现在多种遮挡情况下的行人跟踪,本文提出了一种基于深度学习的行人跟踪框架:根据物体检测算法Faster R-CNN训练了... 在计算机视觉领域已经提出了很多物体跟踪算法和多人跟踪算法,但是遮挡一直是跟踪领域一个具有较大挑战性的问题.为了实现在多种遮挡情况下的行人跟踪,本文提出了一种基于深度学习的行人跟踪框架:根据物体检测算法Faster R-CNN训练了一个行人检测算法作为行人跟踪的搜索机制,相比于梯度下降算法这个机制在缩小搜索范围的同时提高了准确度;利用颜色直方图和尺度不变特征相结合作为目标的表示方式,在目标匹配的过程中,基于FCN图像语义分割算法训练了一个针对行人全卷积网络来提取目标模型中的行人信息以便于去除背景的噪声影响.在数据库OTB上与其他跟踪方法进行了比较,结果显示所提出方法比其他跟踪器在有遮挡的情况下提高了跟踪的准确率和成功率. 展开更多
关键词 FASTER R-CNN SIFT FCN 图像语义分割算法 颜色直方图
极性分子HC2n+1(n=2,3,4)强场搜寻态减速 预览
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作者 陈凯 黄云霞 杨晓华 《化学物理学报》 SCIE CAS CSCD 2017年第4期418-422,I0001共6页
激光辅助Stark减速方案可用于减速强场搜寻态的基态ICI分子,然而,1.0×10^10W/cm^2的激光强度在实验中难以实现.三维Monte—Carlo模拟时间飞行信号表明减速HC2n+1(n=2,3,4)这类分子在实验上更加可行,因为辅助激光强度仅... 激光辅助Stark减速方案可用于减速强场搜寻态的基态ICI分子,然而,1.0×10^10W/cm^2的激光强度在实验中难以实现.三维Monte—Carlo模拟时间飞行信号表明减速HC2n+1(n=2,3,4)这类分子在实验上更加可行,因为辅助激光强度仅为激光辅助Stark方案的1/10. 展开更多
关键词 Stark减速 光学Stark效应 分子减速
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Zeeman Effect of the Rovibronic Ground State of I35Cl at Hyperfine Level
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作者 陈凯 胡正 +1 位作者 王庆辉 杨晓华 《中国物理快报:英文版》 SCIE CAS CSCD 2017年第10期31-33,共3页
Zeeman effect at the hyperfine level of the rovibronic ground state of I~(35) Cl are determined on the basis of|I_1 JF_1 I_2 FM_F) via an effective Hamiltonian matrix diagonalization method. Perturbations of the Zeema... Zeeman effect at the hyperfine level of the rovibronic ground state of I~(35) Cl are determined on the basis of|I_1 JF_1 I_2 FM_F) via an effective Hamiltonian matrix diagonalization method. Perturbations of the Zeeman sublevels are observed and the perturbation selection rules are summarized as well. Several potential applications of such Zeeman effect are suggested. 展开更多
关键词 超精细能级 塞曼效应 基态 对角化方法 哈密顿矩阵 选择规则 扰动
The Ellipsoidal Invariant Set of Fractional Order Systems Subject to Actuator Saturation:The Convex Combination Form 预览
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作者 Kai Chen Junguo Lu Chuang Li 《自动化学报:英文版》 EI 2016年第3期311-319,共9页
The domain of attraction of a class of fractional order systems subject to saturating actuators is investigated in this paper. We show the domain of attraction is the convex hull of a set of ellipsoids. In this paper,... The domain of attraction of a class of fractional order systems subject to saturating actuators is investigated in this paper. We show the domain of attraction is the convex hull of a set of ellipsoids. In this paper, the Lyapunov direct approach and fractional order inequality are applied to estimating the domain of attraction for fractional order systems subject to actuator saturation. We demonstrate that the convex hull of ellipsoids can be made invariant for saturating actuators if each ellipsoid with a bounded control of the saturating actuators is invariant. The estimation on the contractively invariant ellipsoid and construction of the continuous feedback law are derived in terms of linear matrix inequalities(LMIs). Two numerical examples illustrate the effectiveness of the developed method. 展开更多
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NEW ERA SOFTWARE DEFINED NETWORK 预览
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作者 Bi Jun Seungwon Shin Kai Chen 《中国通信:英文版》 SCIE CSCD 2016年第3期I0002-I0003,共2页
<正>Software-Defined Networking(SDN)is now considered as one of the promising future networking technologies,and this trend can be clearly verified by observing activities of both industry and academia.In indust... <正>Software-Defined Networking(SDN)is now considered as one of the promising future networking technologies,and this trend can be clearly verified by observing activities of both industry and academia.In industry,we can easily notice that many major network 展开更多
关键词 网络公司 软件定义 SDN 工业界 学术界 思科
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QTL underlying iron and zinc toxicity tolerances at seedling stage revealed by two sets of reciprocal introgression populations of rice(Oryza sativa L.) 预览
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作者 Huan Liu Aijaz Soomro +6 位作者 Yajun Zhu Xianjin Qiu Kai Chen Tianqing Zheng Longwei Yang Danying Xing Jianlong Xu 《作物学报:英文版》 CAS CSCD 2016年第4期280-289,共10页
Iron and zinc are two trace elements that are essential for rice. But they are toxic at higher concentrations, leading to severe rice yield losses especially in acid soils and inland valleys. In this study, two recipr... Iron and zinc are two trace elements that are essential for rice. But they are toxic at higher concentrations, leading to severe rice yield losses especially in acid soils and inland valleys. In this study, two reciprocal introgression line(IL) populations sharing the same parents were used with high-density SNP bin markers to identify QTL tolerant to iron and zinc toxicities. The results indicated that the japonica variety 02,428 had stronger tolerance to iron and zinc toxicities than the indica variety Minghui 63. Nine and ten QTL contributing to iron and zinc toxicity tolerances,respectively, were identified in the two IL populations. The favorable alleles of most QTL came from 02,428. Among them, q FRRDW2, q ZRRDW3, and q FRSDW11 appeared to be independent of genetic background. The region C11S49–C11S60 on chromosome 11 harbored QTL affecting multiple iron and zinc toxicity tolerance-related traits, indicating partial genetic overlap between the two toxicity tolerances. Our results provide essential information and materials for developing excellent rice cultivars with iron and/or zinc tolerance by marker-assisted selection(MAS). 展开更多
关键词 RICE Reciprocal INTROGRESSION lines IRON TOLERANCE Zinc TOLERANCE Quantitative trait locus/loci(QTL)
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CRISPR/Cas9:A powerful tool for crop genome editing 预览
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作者 Gaoyuan Song Meiling Jia +5 位作者 Kai Chen Xingchen Kong Bushra Khattak Chuanxiao Xie Aili Li Long Mao 《作物学报:英文版》 CAS CSCD 2016年第2期75-82,共8页
The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modificatio... The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA(usually about 20nucleotides) that is complementary to a target gene or locus and is anchored by a protospaceradjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks(DSBs), which are subsequently repaired by non-homologous end joining(NHEJ) or homology-directed repair(HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions,whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement. 展开更多
关键词 CRISPR/Cas9 Double-strand BREAK GENOME EDITING TALENs ZFNs
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基于FFMPEG的跨平台视频编解码研究 预览 被引量:2
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作者 陈天喜 刘黎明 陈凯 《工业技术创新》 2016年第4期805-808,共4页
视频监控系统在生产、生活及社会安全中发挥着越来越重要的作用,各行各业对其需求也越来越高。本文介绍了企业中视频监控系统可用于监管全企业的运行状态,也可应用传感器等实现生产线状态监控、反馈和调整;阐述了视频解编码技术对视频... 视频监控系统在生产、生活及社会安全中发挥着越来越重要的作用,各行各业对其需求也越来越高。本文介绍了企业中视频监控系统可用于监管全企业的运行状态,也可应用传感器等实现生产线状态监控、反馈和调整;阐述了视频解编码技术对视频文件的编码解码,实现视频存储、调用、分析处理及终端播放等功能;最后针对FFMPEG多媒体跨平台的视频编解码技术进行了详细的阐述。本文的思想可供同行参考借鉴。 展开更多
关键词 FFMPEG 视频编解码 跨平台 监控系统
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多杀菌素生物合成的研究进展 被引量:1
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作者 盛志 陈凯 李旭 《微生物学报》 CAS CSCD 北大核心 2016年第3期397-405,共9页
多杀菌素是在刺糖多胞菌发酵液中提取的一种大环内酯类生物杀虫剂,它对靶标昆虫具有独特的快速触杀和摄食毒性,兼具化学农药的速效性和生物农药的安全性,具有低残留、快速降解等优点。本文介绍了多杀菌素的生物合成途径和体外合成方法,... 多杀菌素是在刺糖多胞菌发酵液中提取的一种大环内酯类生物杀虫剂,它对靶标昆虫具有独特的快速触杀和摄食毒性,兼具化学农药的速效性和生物农药的安全性,具有低残留、快速降解等优点。本文介绍了多杀菌素的生物合成途径和体外合成方法,对随机诱变、代谢工程定向改造等刺糖多孢菌工业菌株育种方法进行了介绍,对多杀菌素在异源宿主中的合成进行了讨论。 展开更多
关键词 多杀菌素 刺糖多孢菌 生物农药 生物合成
CA 199水平在2型糖尿病患者人群中对于血糖控制的评估价值 预览
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作者 陈凯 徐海燕 何银辉 《世界华人消化杂志》 CAS 2016年第19期3064-3067,共4页
目的:分析2型糖尿病患者血清糖链抗原199(carbohydrate antigen 199,CA199)水平与血糖控制的相关性.方法:测定77例住院2型糖尿病患者血清CA199水平,分别根据糖化血红蛋白、空腹血糖、餐后2h血糖水平将糖尿病患者分为低糖化组、高糖... 目的:分析2型糖尿病患者血清糖链抗原199(carbohydrate antigen 199,CA199)水平与血糖控制的相关性.方法:测定77例住院2型糖尿病患者血清CA199水平,分别根据糖化血红蛋白、空腹血糖、餐后2h血糖水平将糖尿病患者分为低糖化组、高糖化组、空腹血糖达标组、高空腹血糖组、餐后血糖达标组及餐后高血糖组.比较各组CA199水平;分别计算糖化血红蛋白、空腹血糖、餐后2 h时血糖、年龄、病程、体质量指数、总胆固醇、甘油三酯、高密度脂蛋白胆固醇,低密度脂蛋白胆固醇与CA199的相关性并进行多元Logistic回归分析,比较各变量与CA199的相关程度.结果:高Hb A1c患者的CA199水平为15.77U/m L(10.15-26.34 U/m L)显著高于低Hb A1c的10.23 U/m L(6.34-15.34 U/m L)(Z=-3.455,P〈0.05),高空腹血糖组血清CA199水平14.34U/m L(9.35-26.38 U/m L)也高于正常空腹血糖组的13.17 U/m L(9.38-24.58 U/m L)(Z=-2.348,P〈0.05).高餐后血糖组血清和正常餐后血糖组血清CA199水平比较无统计学差异(Z=-0.183,P〉0.05).Spearman相关分析显示,CA199与糖化血红蛋白(r=0.234,P=0.001)、空腹血糖(r=0.245,P〈0.001)呈正相关(r=0.534,P=0.001),与餐后2 h血糖、胰岛素抵抗及胰岛B细胞功能无相关性.结论:2型糖尿病患者血清CA199水平与糖化血红蛋白及空腹血糖成正相关,与餐后2小时血糖无明显相关性. 展开更多
关键词 2型糖尿病 糖链抗原199 血糖
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Closed-loop correction and ocular wavefronts compensation of a 62-element silicon unimorph deformable mirror
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作者 马剑强 陈凯 +2 位作者 陈俊杰 李保庆 褚家如 《中国光学快报:英文版》 SCIE EI CAS CSCD 2015年第4期76-79,共4页
Adaptive optics(AO) systems greatly improve the resolution of retinal imaging instruments by actively correcting ocular aberrations. In this Letter, closed-loop correction as well as ocular aberration compensation of ... Adaptive optics(AO) systems greatly improve the resolution of retinal imaging instruments by actively correcting ocular aberrations. In this Letter, closed-loop correction as well as ocular aberration compensation of a 62-element silicon unimorph deformable mirror(DM) driven by only positive voltage is performed. The experimental results show that the root-mean square(RMS) wavefront of the initial mirror surface is reduced to0.011 μm in a closed-loop AO system. The DM reproduces Zernike shapes from the third to 35 th mode accurately. The simulated compensation of 200 ocular wavefronts shows that the average RMS value after correction is reduced to 0.017 μm. 展开更多
关键词 闭环校正 像差补偿 硅单晶片 自适应光学系统 波阵面 变形镜 RMS值 变形反射镜
氧化苦参碱对TGF-β1刺激的胰腺星状细胞Smad通路相关因子表达的影响 预览 被引量:8
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作者 陈凯 荣亚梅 +2 位作者 曹卫丽 宗林飞 冀润利 《世界华人消化杂志》 CAS 2015年第12期1883-1889,共7页
目的:观察氧化苦参碱(oxymatrine,OM)对转化生长因子β1(transforming growth factor-β1,TGF-β1)刺激的胰腺星状细胞株LTC-14细胞株Smad通路信号分子Smad2/3/4/7的影响.方法:取大鼠胰腺星状细胞株LTC-14细胞,分别分为对照组、T... 目的:观察氧化苦参碱(oxymatrine,OM)对转化生长因子β1(transforming growth factor-β1,TGF-β1)刺激的胰腺星状细胞株LTC-14细胞株Smad通路信号分子Smad2/3/4/7的影响.方法:取大鼠胰腺星状细胞株LTC-14细胞,分别分为对照组、TGF-β1刺激组、OM干预组[TGF-β1+OM(1 mg/m L)]组.12 h后提取细胞RNA及蛋白,应用实时定量PCR及Western blot检测基因及蛋白表达量的变化情况.结果:OM干预组与TGF-β1刺激组相比,OM干预组均可降低Smad2/3/4基因及蛋白表达,结果有统计学意义(OM干预组vs TGF-β1刺激组,P〈0.05).OM干预组与TGF-β1刺激组相比,OM干预组使Smad7基因表达降低(OM干预组vs TGF-β1刺激组,P〈0.05),Smad7蛋白表达升高(OM干预组vs TGF-β1刺激组,P〈0.05).结论:体外实验中OM可以干预TG F-β1/Smad通路相关信号因子的基因蛋白表达;可能对TGF-β1介导的胰腺星状细胞为核心的胰腺纤维化过程存在治疗作用. 展开更多
关键词 氧化苦参碱 胰腺形状细胞 转化生长因子Β1 SMAD
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氧化苦参碱对胰腺星状细胞中脂多糖诱导的NF-κB表达的影响 预览 被引量:4
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作者 荣亚梅 夏时海 +2 位作者 向晓辉 陈凯 张志广 《世界华人消化杂志》 CAS 2015年第5期761-766,共6页
目的:观察氧化苦参碱(oxymatrine,OM)对脂多糖(lipopolysaccharide,LPS)诱导胰腺星状细胞(LTC-14细胞株)中核因子-κB(nuclear factorκB,NF-κB)表达和核易位的影响.方法:体外培养LTC-14细胞,分别用相应浓度的LPS和/或OM刺激... 目的:观察氧化苦参碱(oxymatrine,OM)对脂多糖(lipopolysaccharide,LPS)诱导胰腺星状细胞(LTC-14细胞株)中核因子-κB(nuclear factorκB,NF-κB)表达和核易位的影响.方法:体外培养LTC-14细胞,分别用相应浓度的LPS和/或OM刺激后,检测NF-κB的表达.用MTT法检测细胞增殖活性,免疫细胞化学技术检测LTC-14细胞胞浆和胞核内NF-κB的表达,实时荧光定量PCR检测细胞内NF-κB mRNA的表达,Western blot法检测NF-κB蛋白含量.结果:OM呈时间-剂量依赖性地抑制LTC-14细胞增殖,LPS(10μg/mL)刺激LTC-14细胞引起NF-κB mRNA及其蛋白表达量增高,NF-κB核内易位量明显增加,OM干预后可以下调NF-κB mRNA和蛋白表达,抑制NF-κB核内易位.结论:对LPS诱导的LTC-14细胞NF-κB mRNA、蛋白表达及NF-κB向核内易位抑制作用可能是OM治疗胰腺纤维化的机制之一. 展开更多
关键词 氧化苦参碱 胰腺星状细胞 NF-ΚB 慢性胰腺炎
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Potential role of NADPH oxidase in pathogenesis of pancreatitis 预览 被引量:1
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作者 Wei-Li Cao Xiao-Hui Xiang +2 位作者 Kai Chen Wei Xu Shi-Hai Xia 《世界胃肠病理生理学杂志:英文版(电子版)》 2014年第3期169-177,共9页
Studies have demonstrated that reactive oxygen species(ROS) are closely related to inflammatory disorders. Nicotinamide adenine dinucleotide phosphate oxidase(NOX), originally found in phagocytes, is the main source ... Studies have demonstrated that reactive oxygen species(ROS) are closely related to inflammatory disorders. Nicotinamide adenine dinucleotide phosphate oxidase(NOX), originally found in phagocytes, is the main source of ROS in nonphagocytic cells. Besides directly producing the detrimental highly reactive ROS to act on biomolecules(lipids, proteins, and nucleic acids), NOX can also activate multiple signal transduction pathways, which regulate cell growth, proliferation, differentiation and apoptosis by producing ROS. Recently, research on pancreatic NOX is no longer limited to inflammatory cells, but extends to the aspect of pancreatic acinar cells and pancreatic stellate cells, which are considered to be potentially associated with pancreatitis. In this review, we summarize the literature on NOX protein structure, activation, function and its role in the pathogenesis of pancreatitis. 展开更多
关键词 NICOTINAMIDE ADENINE DINUCLEOTIDE phosphate oxidase Reactive oxygen species PANCREATITIS PANCREATIC acinar CELLS PANCREATIC stellate CELLS
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miR-31对人皮肤鳞状细胞癌生长的影响及作用机制的研究 预览 被引量:5
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作者 陈凯 常东方 +1 位作者 段绍坤 李渝凉 《中国肿瘤临床》 CAS CSCD 北大核心 2014年第9期555-559,共5页
目的:探讨miR-31对皮肤鳞状细胞癌(鳞癌)生长的影响及作用机制。方法:在鳞癌细胞中转染miR-31的2&#39;-羟基甲基化的反义寡核苷酸(antisense oligonueleotide,ASO),运用平板克隆形成和体外成瘤实验检测miR-31对鳞癌生长的影响... 目的:探讨miR-31对皮肤鳞状细胞癌(鳞癌)生长的影响及作用机制。方法:在鳞癌细胞中转染miR-31的2&#39;-羟基甲基化的反义寡核苷酸(antisense oligonueleotide,ASO),运用平板克隆形成和体外成瘤实验检测miR-31对鳞癌生长的影响。运用Western blot印迹及GFP报告基因实验验证miR-31的靶基因。在鳞癌细胞中转染靶基因的siRNA,检测其对细胞生长的影响。最后,运用实时定量PCR以及免疫组织化学检测miR-31和靶基因在鳞癌组织中的水平。结果:转染miR-31反义寡核苷酸(miR-31 ASO)可以抑制克隆数目及体内裸鼠肿瘤体积(P〈0.05)。LATS2(large tumor suppressor homolog 2)是miR-31的直接靶基因。抑制LATS2表达后,鳞癌细胞克隆数目增加(P〈0.05)。miR-31在鳞癌中高表达,与LATS2的表达呈负相关。免疫组织化学结果也显示LATS2在鳞癌组织中低表达。结论:miR-31通过负调控LATS2抑制鳞癌的生长。因此,miR-31具有作为鳞癌分子治疗靶标的潜能。 展开更多
关键词 鳞状细胞癌
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The investigation on computational grids in wind turbine positioning optimization using greedy algorithm
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作者 Kai Chen Mengxuan Song Xing Zhang 《中国科学通报:英文版》 SCIE CAS 2014年第26期3304-3313,共10页
在这份报纸,放优化的风汽轮机上的计算格子的效果被学习。线性醒来流动模型被用来计算汽轮机醒来流动。幂定律被用来为风汽轮机的力量曲线建模。有重复调整的贪婪算法被介绍解决放问题的风汽轮机,与最大化风农场的全部的力量产量的目... 在这份报纸,放优化的风汽轮机上的计算格子的效果被学习。线性醒来流动模型被用来计算汽轮机醒来流动。幂定律被用来为风汽轮机的力量曲线建模。有重复调整的贪婪算法被介绍解决放问题的风汽轮机,与最大化风农场的全部的力量产量的目标。有各种各样的取向的方形的格子和三角格子习惯于 discretize 风的区域农场。三个数字盒子被介绍在优化结果上学习计算格子的效果。结果证明优化力量产量能通过选择适当格子取向被改进。为单个方向风大小写和多方向风大小写的建议格子取向被给。 展开更多
关键词 风力涡轮机 计算网格 定位问题 优化 贪心算法 格调 尾流模型 功率输出
Research on the Limit Value of Shape Coefficient of Rural Residences in Severe Cold Regions 预览
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作者 Hong Jin Kai Chen Teng Shao 《哈尔滨工业大学学报:英文版》 EI CAS 2014年第4期43-46,共4页
Shape coefficient is a significant factor accounting for building energy consumption. In order to decrease the building energy consumption of rural residence in severe cold regions,this paper from the perspective of r... Shape coefficient is a significant factor accounting for building energy consumption. In order to decrease the building energy consumption of rural residence in severe cold regions,this paper from the perspective of regulating the shape coefficient limit value,applies the field survey method to statistic and analyze the shape,width and depth of rural residence in severe cold regions and concludes the distribution characteristics and scope of building area. On this basis,though calculating and analyzing the relations between shape coefficient and length-width ratio under different building areas,meanwhile comprehensive considering the building function,farmers’ living mode and requirements etc,it put forward that the shape coefficient of rural residence in severe cold regions should below 0. 8. It has important significance for guiding the rural energy-saving house design and construction of severe cold regions. 展开更多
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基于OPERA/QUENCH的MRI超导对称与非对称磁体失超特性对比
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作者 张冉 杨立欣 +2 位作者 陈凯 孔德平 朱贵友 《低温物理学报》 CAS CSCD 北大核心 2014年第5期359-368,共10页
在MRI磁体的设计过程中,失超现象的研究对于超导磁体的安全运行具有重要的意义.本文采用三维有限元软件OPERA分别对1T对称磁体和非对称磁体的失超特性进行了仿真分析.详细介绍了仿真的建模过程和求解算法.NbTi超导材料的临界电流密度通... 在MRI磁体的设计过程中,失超现象的研究对于超导磁体的安全运行具有重要的意义.本文采用三维有限元软件OPERA分别对1T对称磁体和非对称磁体的失超特性进行了仿真分析.详细介绍了仿真的建模过程和求解算法.NbTi超导材料的临界电流密度通过软件预设的查表变量实现设置.通过仿真分析,得到了两种磁体结构在失超过程中重要的物理量如超导线圈的电流、电阻的变化规律.三维仿真图形更有利于观察失超在不同方向的传播速度.通过比较得出结论,虽然对非称磁体的DSV比对称磁体要大,但在失超过程中,非对称磁体受到的破坏也比对称磁体要严重. 展开更多
关键词 MRI超导磁体 失超特性 对称磁体 非对称磁体
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