期刊文献+
共找到11,272篇文章
< 1 2 250 >
每页显示 20 50 100
Figure-9腔锁模全保偏掺铒光纤飞秒激光器 被引量:1
1
作者 杨小亮 韦佳天 +2 位作者 吕宏伟 陈峰 刘志强 《光通信技术》 2023年第5期58-62,共5页
针对特殊应用领域对高可靠性、轻量化、输出功率大于100 mW、重频大于50 MHz的飞秒激光器的需求,设计了一种Figure-9腔锁模全保偏掺铒光纤飞秒激光器,通过在腔锁模振荡器中引入π/2相移偏置,降低了振荡器的自启动锁模阈值。实验结果表明... 针对特殊应用领域对高可靠性、轻量化、输出功率大于100 mW、重频大于50 MHz的飞秒激光器的需求,设计了一种Figure-9腔锁模全保偏掺铒光纤飞秒激光器,通过在腔锁模振荡器中引入π/2相移偏置,降低了振荡器的自启动锁模阈值。实验结果表明:当泵浦功率为130 mW时,振荡器可获得平均功率为12 mW、重频为85.89 MHz、脉冲宽度为249 fs的稳定锁模脉冲序列输出;采用一级正色后向泵浦散掺铒增益光纤放大器进行放大后,最终可获得平均功率为113 mW、脉冲宽度为107 fs的飞秒脉冲序列输出。 展开更多
关键词 保偏 figure-9腔 激光器 锁模 非线性放大光纤环
下载PDF
Perspectives in human brain plasticity sparked by glioma invasion:from intraoperative(re)mappings to neural reconfigurations
2
作者 Sam Ng Hugues Duffau Guillaume Herbet 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第5期947-948,共2页
Exploring the aptitude of the human brain to compensate functional consequences of a lesion damaging its structural architecture is a key challenge to improve patient care in various neurological diseases,to optimize ... Exploring the aptitude of the human brain to compensate functional consequences of a lesion damaging its structural architecture is a key challenge to improve patient care in various neurological diseases,to optimize neuroscientifically-informed strategies of postlesional rehabilitation,and ultimately to develop innovative neuro-regenerative therapies.The term‘plasticity’,initially referring to the intrinsic propensity of neurons to modulate their synaptic transmission in a learning situation,was progressively transposed to brain injury research and clinical neurosciences.Indeed,in the event of brain damage,adaptive mechanisms of compensation allow a partial reshaping of the structure and activities of the central nervous system,thus permitting to some extent the maintenance of brain functions. 展开更多
关键词 PLASTICITY figuration consequences
下载PDF
利用Breath Figure法制备具有Honeycomb结构的有机/无机复合膜 被引量:6
3
作者 申延明 吴静 +4 位作者 卢欣 唐杨军 刘丹 李长龙 李天舒 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2009年第7期1464-1468,共5页
以聚苯乙烯和正硅酸乙酯的有机溶液为铸膜溶液,利用Breath Figure法制备了PS/SiO2 Honeycomb结构复合膜.采用SEM对复合膜进行了形貌分析,探讨了聚合物浓度、PS/TEOS配比、聚合物的结构、溶剂等对膜Honeycomb结构的影响.研究结果表明,聚... 以聚苯乙烯和正硅酸乙酯的有机溶液为铸膜溶液,利用Breath Figure法制备了PS/SiO2 Honeycomb结构复合膜.采用SEM对复合膜进行了形貌分析,探讨了聚合物浓度、PS/TEOS配比、聚合物的结构、溶剂等对膜Honeycomb结构的影响.研究结果表明,聚合物浓度在20~50mg/mL,PS/TEOS质量比大于2∶1的条件下可以制备结构完整的多孔膜,且制备的Honeycomb结构在0.8cm2内无缺陷;采用双羧基封端的聚苯乙烯成膜效果好于单羧基封端的成膜效果;以氯仿和苯作为溶剂均可以制备完全Honeycomb结构的复合膜,但以苯为溶剂制备的多孔膜孔径较大.成膜中TEOS水解不完全,复合膜中混杂着未完全水解的TEOS以及SiO2.EDS面扫描分析表明,Si和O均匀地分散在复合膜中. 展开更多
关键词 BREATH figure 水辅助法 有序多孔膜 Honeycomb结构 有机/无机复合膜
下载PDF
Breath Figure法制备聚碳酸酯(PC)蜂窝状多孔膜 被引量:3
4
作者 刘瑞来 刘俊劭 刘海清 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2013年第3期133-136,共4页
以单组分聚碳酸酯(PC)为膜材质,在一定的湿度环境下,利用Breath Figure法在玻璃基板上成功制备了蜂窝状孔结构的聚碳酸酯多孔膜。研究了溶剂、溶液浓度和湿度对所成多孔膜结构和形貌的影响。实验结果表明,采用二氯甲烷为溶剂所制得的孔... 以单组分聚碳酸酯(PC)为膜材质,在一定的湿度环境下,利用Breath Figure法在玻璃基板上成功制备了蜂窝状孔结构的聚碳酸酯多孔膜。研究了溶剂、溶液浓度和湿度对所成多孔膜结构和形貌的影响。实验结果表明,采用二氯甲烷为溶剂所制得的孔结构规整,排列均匀紧密,孔径大小为(3.30±0.19)μm,而以三氯甲烷为溶剂只能得到孔径大小不均且无紧密排列的孔。环境湿度从43%增加到91%,孔径大小由(2.28±0.63)μm增加到(9.07±1.42)μm,且湿度与孔大小基本上呈现一阶线性关系,通过理论推导得出直线斜率为0.15μm/%,即在此体系中湿度每增加1%,所形成的孔大小增加0.15μm。 展开更多
关键词 聚碳酸酯 BREATH figure 蜂窝孔
下载PDF
Lichtenberg Figures 技术的新应用 被引量:2
5
作者 徐伟军 翁明 郑德修 《电工电能新技术》 CSCD 1999年第1期36-39,共4页
本文叙述了LichtenbergFigures(李庭博图)技术的新应用,即KirlianPho-tography(电晕放电成像)技术的基本原理。提出了影响成像清晰度的关键问题是外部电脉冲的宽度,并用纳秒脉冲放电技术获... 本文叙述了LichtenbergFigures(李庭博图)技术的新应用,即KirlianPho-tography(电晕放电成像)技术的基本原理。提出了影响成像清晰度的关键问题是外部电脉冲的宽度,并用纳秒脉冲放电技术获得了清晰的电晕像。同时就KirlianPho-tography的应用提出了一些看法。 展开更多
关键词 李庭博图 电晕放电 纳秒脉冲 放电 脉冲放电
下载PDF
Relationship Between Noise Figure and Equivalent Input Noise Current Spectral Density for Optical Receiver Design
6
作者 孙玲 王志功 +1 位作者 景为平 高建军 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第12期2085-2088,共4页
Based on the equivalent circuit model of a two-port optical receiver front-end,the relationship between the equivalent input noise current spectral density and the noise figure is analyzed. The derived relationship ha... Based on the equivalent circuit model of a two-port optical receiver front-end,the relationship between the equivalent input noise current spectral density and the noise figure is analyzed. The derived relationship has universal validity for determining the equivalent input noise current spectral density for optical receiver designs, as verified by measuring a 155Mb/s high-impedance optical receiver front.end. Good agreement between calculated and simulated results has been achieved. 展开更多
关键词 optical receiver noise figure equivalent input noise current
下载PDF
汉语名词短语及存现句语序的“Ground-to-Figure”假说 被引量:1
7
作者 郑晓行 《现代语文(下旬.语言研究)》 2015年第8期57-62,共6页
20世纪以来的汉语语序研究虽然取得了不少成果,但仍需要全面、系统和深入的研究。从"以运用为基础"的认知语言学研究范式来看,汉语句法结构通过概念隐喻在汉语使用者的日常空间思维的基础上生成,因此,汉语名词短语:"……... 20世纪以来的汉语语序研究虽然取得了不少成果,但仍需要全面、系统和深入的研究。从"以运用为基础"的认知语言学研究范式来看,汉语句法结构通过概念隐喻在汉语使用者的日常空间思维的基础上生成,因此,汉语名词短语:"……>名词整体(背景)>名词部分(图形)>……""……>名词大(背景)>名词小(图形)>……""……>名词空间/时间(背景)>名词对象(图形)>……"和存现句"……(NPloc/time)……(V)……(NP)……"等语序在汉语使用者的"Ground-to-Figure"的认知过程的基础上生成。在此基础上提出的汉语名词短语及存现句的"Ground-to-Figure"假说是一条汉语语序生成的重要机制,但不是唯一机制。 展开更多
关键词 汉语名词短语 存现句 语序 Ground—to—figure
下载PDF
The figures of speech in Song of Solomon
8
作者 张伟 《神州》 2014年第17期29-29,共1页
The Song of Solomon is a series of love poems which contain 6 pieces of love poems and most part in the form of songs addressed by a man to a woman, and by the woman to the man, in order to express the love between th... The Song of Solomon is a series of love poems which contain 6 pieces of love poems and most part in the form of songs addressed by a man to a woman, and by the woman to the man, in order to express the love between them.Figures of speech are ways of making our language figurative. They can be divided into three parts, they are syntactical, semantic and phonetic rhetorical devices. These rhetorical devices can help us to heighten effect and to make the writing figuratively and vividly.These figures of speech used in the Song of Solomon make great contribution to the success description of these long songs.This essay will center on the figures of speech in the Song of Solomon. 展开更多
关键词 SOLOMON RHETORICAL figureS PHONETIC SENTENCE semantic writing pieces PARALLELISM beauty
下载PDF
Breath Figures法制备漆酚铜聚合物多孔膜 被引量:1
9
作者 罗震 徐艳莲 林金火 《功能材料》 EI CAS CSCD 北大核心 2012年第1期69-72,共4页
以漆酚铜聚合物(UCP)有机溶液为铸膜液,采用Breath Figures法制备漆酚铜聚合物多孔膜,探讨了溶剂、环境相对湿度和潮湿气体流速等因素对多孔膜形貌的影响,并使用红外光谱和扫描电镜等进行表征。结果表明,以二硫化碳为溶剂,在静态(潮湿... 以漆酚铜聚合物(UCP)有机溶液为铸膜液,采用Breath Figures法制备漆酚铜聚合物多孔膜,探讨了溶剂、环境相对湿度和潮湿气体流速等因素对多孔膜形貌的影响,并使用红外光谱和扫描电镜等进行表征。结果表明,以二硫化碳为溶剂,在静态(潮湿气体流速为0mL/min,湿度为95%)或动态(潮湿气体流速为400mL/min,湿度为85%)时,均可制得孔分布均匀、孔型规整、优良耐热性和耐酸碱性的疏水性UCP多孔膜,其平均孔径分别为1.5和0.85μm。 展开更多
关键词 漆酚铜聚合物 多孔膜 BREATH figures法
下载PDF
Two-dimensional precise figuring of 500 mm-long X-ray mirror using one-dimensional ion beam system
10
作者 Qiu-Shi Huang Han-Dan Huang +3 位作者 Qiao-Yu Wu Jun Yu Zhong Zhang Zhan-Shan Wang 《Advances in Manufacturing》 SCIE EI CAS CSCD 2024年第1期177-184,共8页
In this study,a new method was developed to realize two-dimensional(2D)figure correction of grazing-incidence X-ray mirrors using a one-dimensional(1D)ion-beam figuring system.A mask of holes was specifically designed... In this study,a new method was developed to realize two-dimensional(2D)figure correction of grazing-incidence X-ray mirrors using a one-dimensional(1D)ion-beam figuring system.A mask of holes was specifically designed to generate removal functions at different widths and extend the figuring capability over a wide area.Accordingly,a long mirror could be manufactured.Using this method,the surface height root-mean-square(RMS)error of the center area of 484 mm×16 mm was reduced from 11.49 nm to 2.01 nm,and the 1D meridional RMS error reached 1.0 nm.The proposed method exhibits high precision and cost effectiveness for production of long X-ray mirrors. 展开更多
关键词 Long-size mirrors Ion beam figuring two-dimensional figure correction MASK
原文传递
汉语名词短语左递归现象的“Ground-to-Figure”假说——兼论Hauser,Chomsky&Fitch的FLN假说
11
作者 郑晓行 曹杰旺 《淮南师范学院学报》 2016年第1期81-87,共7页
Hauser,Chomsky&Fitch(2002)把"语言器官"区分为FLB和FLN,并假设FLN只包含递归性,(递归性)是人类语言器官独有且唯一的构成要素,它使人类语言可以对"有限的手段进行无限运用"。按照他们的观点,类似汉语名词短... Hauser,Chomsky&Fitch(2002)把"语言器官"区分为FLB和FLN,并假设FLN只包含递归性,(递归性)是人类语言器官独有且唯一的构成要素,它使人类语言可以对"有限的手段进行无限运用"。按照他们的观点,类似汉语名词短语左递归现象均由FLN的递归性生成,这种观点明显不符合汉语实际,也不符合汉语使用者的认知过程。从完形心理学的图形-背景认知原则来说,汉语使用者在认知过程中遵循从背景到图形的顺序,不断切换关注中心,而语言表达也遵循从背景到图形的顺序与之对应,形成了语言使用者对外部事物的完形认知与语言完形表达的异质同构,这就是汉语名词左递归现象的"Ground-to-Figure"假说。汉语名词左递归现象植根于汉语使用者的空间认知,这种语言思维与空间思维之间的同一性关系也得到Lakoff(1987)提出的形式空间化假设的有力的支持,而形式空间化假设又被神经生理学和生物学的研究成果的证实:人类空间思维与语言思维在人类大脑神经系统中由同类结构生成。诸如汉语名词左递归现象的语言递归现象并不是由所谓的FLN的递归性生成,递归性也不是区域限定性的而是区域通用性的,不为FLN独有。从这个意义上说,Hauser,Chomsky&Fitch(2002)的FLN假说是错误的。 展开更多
关键词 汉语名词短语左递归现象 'Ground-to-figure'假说 递归性 FLB FLN
下载PDF
Breath Figure法制备漆酚铁聚合物微米图案的研究 被引量:1
12
作者 金遥 彭嬖琛 +2 位作者 冯丽霞 罗震 徐艳莲 《中国生漆》 2012年第1期6-8,50,共4页
以漆酚铁聚合物(UFP)为基材,采用BreathFigure法制备UFP多孔膜和UFP微球。用扫描电镜观察其形貌,并研究(1)静态和动态的高湿环境下,浓度对UFP多孔膜形貌的影响;(2)聚合物浓度和温度等对UFP微球形貌的影响。结果表明,当环境湿度为85%、... 以漆酚铁聚合物(UFP)为基材,采用BreathFigure法制备UFP多孔膜和UFP微球。用扫描电镜观察其形貌,并研究(1)静态和动态的高湿环境下,浓度对UFP多孔膜形貌的影响;(2)聚合物浓度和温度等对UFP微球形貌的影响。结果表明,当环境湿度为85%、潮湿气体流速为400mL/min、聚合物浓度为50.0mg/mL,多孔膜的孔呈圆形且分布均匀。当UFP/二氯甲烷浓度为50.0mg/mL、气氛为甲醇及进样量为10.0μL时,所得的微球的形貌较好。在实验范围内,UFP溶液浓度越大,所制得的UFP多孔膜和微球的形貌越规整。 展开更多
关键词 漆酚铁聚合物 BREATH figure 多孔膜 微球
下载PDF
Symbolic Images of Figures in The Red Badge of Courage
13
作者 王晓俊 《海外英语》 2014年第3X期5-7,9,共4页
Crane’s most well-known work,The Red Badge of Courage,is commonly believed to be the first great novel of the American Civil War,largely because of its vivid and detailed description of the experience of warfare.This... Crane’s most well-known work,The Red Badge of Courage,is commonly believed to be the first great novel of the American Civil War,largely because of its vivid and detailed description of the experience of warfare.This paper conveys figure images symbolize that human life is insignificant in an indifferent universe in the novel,which are perfect symbolic images distinguish Crane as a forerunner of modernistic writers. 展开更多
关键词 CRANE The Red BADGE of COURAGE SYMBOLIC images FIG
下载PDF
A high figure of merit localized surface plasmon sensor based on a gold nanograting on the top of a gold planar film 被引量:1
14
作者 张祖银 王立娜 +3 位作者 胡海峰 李康文 马勋鹏 宋国峰 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期345-348,共4页
We investigate the sensitivity and figure of merit (FOM) of a localized surface plasmon (LSP) sensor with gold nanograting on the top of planar metallic film. The sensitivity of the localized surface plasmon senso... We investigate the sensitivity and figure of merit (FOM) of a localized surface plasmon (LSP) sensor with gold nanograting on the top of planar metallic film. The sensitivity of the localized surface plasmon sensor is 317 nm/RIU, and the FOM is predicted to be above 8, which is very high for a localized surface plasmon sensor. By employing the rigorous coupled-wave analysis (RCWA) method, we analyze the distribution of the magnetic field and find that the sensing property of our proposed system is attributed to the interactions between the localized surface plasmon around the gold nanostrips and the surface plasmon polarition on the surface of the gold planar metallic film. These findings are important for developing high FOM localized surface plasmon sensors. 展开更多
关键词 localized surface plasmon biosensor figure of merit nanogratings gold film
下载PDF
Two-Dimensional Euler Adaptive Mesh Method on Detonation 被引量:1
15
作者 郝鹏程 冯其京 姚雯 《Journal of Beijing Institute of Technology》 EI CAS 2009年第2期141-145,共5页
The adaptive mesh refinement (AMR) method is applied in the 2-D Euler multi-component elasticplastic hydrodynamics code (MEPH2Y). It is applied on detonation. Firstly, the AMR method is described, including a cons... The adaptive mesh refinement (AMR) method is applied in the 2-D Euler multi-component elasticplastic hydrodynamics code (MEPH2Y). It is applied on detonation. Firstly, the AMR method is described, including a conservative spatial interpolation, the time integration methodology with the adapitve time increment and an adaptive computational region method. The advantage of AMR technique is exhibited by numerical examples, including the 1-D C-J detonation and the 2-D implosion ignited from a single point. Results show that AMR can promote the computational efficiency, keeping the accuracy in interesting regions. 展开更多
关键词 adaptive mesh refinement (AMR) DETONATION two-dimension EULER numerical simulation
下载PDF
The Synthesis and Structural Characterization of Two-dimensional Coordination Polymer {[Ni(phen)H_2O](μ_4-C_( 10)H_2O_8)_(1/2)}_n 被引量:1
16
作者 YE Ling PAN Cheng-ling +3 位作者 CHU De-qing WANG Li-min MU Zhong-cheng XU Ji-qing 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2002年第4期474-477,共4页
关键词 two-dimension Hydrothermal synthesis Inorganic-organic hybrid material Crystal structure
下载PDF
COMPACTLY SUPPORTED NON-TENSOR PRODUCT FORM TWO-DIMENSION WAVELET FINITE ELEMENT 被引量:1
17
作者 金坚明 薛鹏翔 +1 位作者 徐应祥 朱亚莉 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第12期1673-1686,共14页
Some theorems of compactly supported non-tensor product form two-dimension Daubechies wavelet were analysed carefully. Compactly supported non-tensor product form two-dimension wavelet was constructed, then non-tensor... Some theorems of compactly supported non-tensor product form two-dimension Daubechies wavelet were analysed carefully. Compactly supported non-tensor product form two-dimension wavelet was constructed, then non-tensor product form two dimension wavelet finite element was used to solve the deflection problem of elastic thin plate. The error order was researched. A numerical example was given at last. 展开更多
关键词 compactly supported non-tensor product two-dimension wavelet interpolation function elastic thin plate DEFLECTION finite element
下载PDF
Female Figures in Tragedy—The Comparison of Female Figures in Shakespeare's Macbeth and Polanski's Film Version of Macbeth 被引量:1
18
作者 李珊珊 《英语广场(学术研究)》 2011年第Z4期29-30,36,共3页
莎士比亚的戏剧作品自问世以来就一直受到人们的极大追捧,《麦克白》作为四大悲剧之一,更是被不断地被演绎、研究。波兰斯基的电影《麦克白》重新展现了莎翁的名作,他在保留原作精华的同时,将自己对《麦克白》中女性人物的理解更深刻地... 莎士比亚的戏剧作品自问世以来就一直受到人们的极大追捧,《麦克白》作为四大悲剧之一,更是被不断地被演绎、研究。波兰斯基的电影《麦克白》重新展现了莎翁的名作,他在保留原作精华的同时,将自己对《麦克白》中女性人物的理解更深刻地表现出来了。本文拟通过麦克白夫人和女巫,来分析莎士比亚对剧本中女性人物的刻画,再将波兰斯基的影片与之对比,并结合波兰斯基生平,对其创作意图试做猜想。 展开更多
关键词 莎士比亚 波兰斯基 麦克白 女性人物
下载PDF
Different Frequency Synchronization Theory and Its Frequency Measurement Practice Teaching Innovation Based on Lissajous Figure Method 被引量:1
19
作者 Xin Geng Songlin Li +2 位作者 Guangming Huang Baoqiang Du Jianhua Chen 《Journal of Beijing Institute of Technology》 EI CAS 2018年第2期198-205,共8页
According to the requirement of multi-parameter time and frequency measurement without frequency normalization,a different frequency synchronization theory is proposed based on Lissajous figure method and the variatio... According to the requirement of multi-parameter time and frequency measurement without frequency normalization,a different frequency synchronization theory is proposed based on Lissajous figure method and the variation lawof Lissajous figure which are used in practice teaching of frequency measurement. The theory can achieve high-precision transmission and comparison of time and frequency and precise locking and tracking of phase and frequency,improve the level of scientific research on time and frequency for postgraduate,and promote practice teaching innovation of time frequency measurement for undergraduate. Utilizing the ratio of horizontal and vertical inflection point of the Lissajous figure,the nominal frequency of the measured signal is precisely calculated.The frequency deviation between the measured frequency and its nominal frequency can be obtained by combining the turning cycle of the Lissajous figure. By observing the phase relationship between the frequency standard signal and the measured signal,the accurate measurement of the frequency is implemented. Experimental results showthat the direct measurement and comparison better than the 10-11 order of magnitude with common frequency source can be finished between any signal frequencies.The frequency measurement method based on the theory has the advantage of simple operation,quick measurement speed,small error,lownoise and high measurement precision. It plays an important role in time synchronization,communications,metrology,scientific research,educational technology practice and equipment and other fields. 展开更多
关键词 Lissajous figure different frequency synchronization frequency measurement
下载PDF
Figure of Merit Analysis of a Hybrid Solar-geothermal Power Plant 被引量:1
20
作者 Cheng Zhou Elham Doroodchi Behdad Moghtaderi 《Engineering(科研)》 2013年第1期26-31,共6页
Figure of merit analysis is a general methodology used to evaluate whether a hybrid power plant could produce more power than two stand-alone power plants. In this paper, the assessment methodology using figure of mer... Figure of merit analysis is a general methodology used to evaluate whether a hybrid power plant could produce more power than two stand-alone power plants. In this paper, the assessment methodology using figure of merit analysis was re-examined for a hybrid solar-geothermal power plant. A new definition of the figure of merit was introduced specifically for a solar boosted geothermal plant to include both the technical and economic factors. The new definition was then applied in a case study of a hypothetical demonstration hybrid solar-geothermal power plant in Australia. The power plant was considered to have a typical net power output of 2.2 MW with a solar energy fraction of 27%. The analysis was performed to compare the power output and capital cost of the hybrid plant with the state-of-the-art (SoA) and existing stand-alone solar and geothermal plants. Based on the new definition, the hybrid plant was found to generally outperform the two existing stand-alone plants. Moreover, at an ambient temperature of 5 °C, the hybrid plant was found to outperform the SoA stand-alone plants when the geothermal temperature was greater than 150 °C. For geothermal temperature of 180 °C on the other hand, the hybrid plant outperformed the SoA stand-alone plants at ambient temperatures lower than 33 °C. 展开更多
关键词 figure of MERIT HYBRID RENEWABLE energy system SOLAR GEOTHERMAL Power generation
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部