期刊文献+
共找到84,874篇文章
< 1 2 250 >
每页显示 20 50 100
A method improving historical accuracy regarding notable figures focused on the biography of Emily Stowe
1
作者 Carol Nash 《History and Philosophy of Medicine》 2026年第1期1-21,共21页
Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented... Background:A significant challenge regarding notable historical figures is determining the accuracy of the words and actions attributed to them with the limited available evidence,when their biographers have presented a biased life assessment.Lauded as a founding suffragette,the first female school principal,and the first white female practicing physician in Canada,Dr.Emily Stowe did not help historians.She destroyed her records,leaving her life story to be told by her daughter,who portrayed her as a heroine–a view that has persisted since the start of the 20th century.To improve the accuracy of assessing the life of Emily Stowe,as much information as possible about Stowe must be collected and interpreted.Methods:Presented is a narrative research method for analyzing historical figures that examines 22 life-changing events in the life of Stowe by answering six types of questions about each event:when,where,who,what,how,and why.Results:This narrative research,representing a psychoanalytic research process,finds that much of the repeated story of Stowe is either exaggerated or likely false.Conclusion:Following the example of Emily Stowe,this unique method is applicable for improving the historical accuracy in assessing the lives of other notable figures.It represents a method extendable to those currently alive,outside the public eye,searching to develop their own narrative. 展开更多
关键词 historical figures Emily Stowe suffragettes female physicians Canada narrative research psychoanalytic research
在线阅读 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
2
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
在线阅读 下载PDF
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
3
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
在线阅读 下载PDF
Chinese Liandong(Serial Verb) Constructions from the Perspective of Figure-Ground Relation
4
作者 刘鹏 《海外英语》 2011年第1X期253-254,256,共3页
Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty cat... Empty categories,which lack phonological form and hence are not visible in the phonetic representation of the sentence,have both syntactic and semantic properties.Null subjects PRO and pro are base-generated empty categories.This thesis,based on Chomsky's theory about empty categories and research achievements made by Chinese scholars,attempts to analyze the liandong(Serial Verb) construction from Figure and Ground perspective. 展开更多
关键词 PRO Liandong(Serial) VERB construction figure-ground
在线阅读 下载PDF
Mild Cognitive Impairment Detection from Rey-Osterrieth Complex Figure Copy Drawings Using a Contrastive Loss Siamese Neural Network
5
作者 Juan Guerrero-Martín Eladio Estella-Nonay +1 位作者 Margarita Bachiller-Mayoral Mariano Rincón 《Computers, Materials & Continua》 2025年第12期4729-4752,共24页
Neuropsychological tests,such as the Rey-Osterrieth complex figure(ROCF)test,help detect mild cognitive impairment(MCI)in adults by assessing cognitive abilities such as planning,organization,and memory.Furthermore,th... Neuropsychological tests,such as the Rey-Osterrieth complex figure(ROCF)test,help detect mild cognitive impairment(MCI)in adults by assessing cognitive abilities such as planning,organization,and memory.Furthermore,they are inexpensive and minimally invasive,making them excellent tools for early screening.In this paper,we propose the use of image analysis models to characterize the relationship between an individual’s ROCF drawing and their cognitive state.This task is usually framed as a classification problem and is solved using deep learning models,due to their success in the last decade.In order to achieve good performance,these models need to be trained with a large number of examples.Given that our data availability is limited,we alternatively treat our task as a similarity learning problem,performing pairwise ROCF drawing comparisons to define groups that represent different cognitive states.This way of working could lead to better data utilization and improved model performance.To solve the similarity learning problem,we propose a siamese neural network(SNN)that exploits the distances of arbitrary ROCF drawings to the ideal representation of the ROCF.Our proposal is compared against various deep learning models designed for classification using a public dataset of 528 ROCF copy drawings,which are associated with either healthy individuals or those with MCI.Quantitative results are derived from a scheme involving multiple rounds of evaluation,employing both a dedicated test set and 14-fold cross-validation.Our SNN proposal demonstrates superiority in validation performance,and test results comparable to those of the classification-based deep learning models. 展开更多
关键词 Mild cognitive impairment detection Rey-Osterrieth complex figure deep learning siamese neural network
在线阅读 下载PDF
Analysis of English Complex Sentences based on Figure-Ground Theory
6
作者 侯皓 《疯狂英语(教师版)》 2015年第4期149-153,共5页
English is a language featuring its complex sentences composed of main and subordinate clauses. The subordinate clause conveys the unfinished messages in main clause and it becomes quite complicated. English complex s... English is a language featuring its complex sentences composed of main and subordinate clauses. The subordinate clause conveys the unfinished messages in main clause and it becomes quite complicated. English complex sentence is a fair important sentence type and also of importance in English teaching. Analyzing complex sentence based on Figure-Ground Theory, especially the Adverbial Clause, is helpful to learn English and translate it. The Figure-Ground Theory originated in psychology studies and it was introduced in cognitive linguistics to explain some language phenomena. From Figure-Ground perspective, the essay studies attributive clause,adverbial clause and nominal clause and some critical sentence types have been analyzed carefully and the major finding is Figure-Ground Theory is dynamic not static. 展开更多
关键词 figure-ground Theory attributive clause nominal clause adverbial clause
在线阅读 下载PDF
Time-dependent ground stability of inclined backfilled stope characterized by creep behavior
7
作者 Ruofan Wang Yujie Zhu +3 位作者 Lang Liu Mengbo Zhu Baoxu Yan Hao Cui 《International Journal of Minerals,Metallurgy and Materials》 2026年第2期479-491,共13页
Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional... Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope. 展开更多
关键词 inclined backfilled stope ground stability time-dependency creep CONSOLIDATION
在线阅读 下载PDF
HS-APF-RRT*: An Off-Road Path-Planning Algorithm for Unmanned Ground Vehicles Based on Hierarchical Sampling and an Enhanced Artificial Potential Field
8
作者 Zhenpeng Jiang Qingquan Liu Ende Wang 《Computers, Materials & Continua》 2026年第1期1218-1235,共18页
Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees l... Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees lead to slow convergence and force an unfavorable trade-off between path quality and traversal safety.To address these challenges,we introduce HS-APF-RRT*,a novel algorithm that fuses layered sampling,an enhanced Artificial Potential Field(APF),and a dynamic neighborhood-expansion mechanism.First,the workspace is hierarchically partitioned into macro,meso,and micro sampling layers,progressively biasing random samples toward safer,lower-energy regions.Second,we augment the traditional APF by incorporating a slope-dependent repulsive term,enabling stronger avoidance of steep obstacles.Third,a dynamic expansion strategy adaptively switches between 8 and 16 connected neighborhoods based on local obstacle density,striking an effective balance between search efficiency and collision-avoidance precision.In simulated off-road scenarios,HS-APF-RRT*is benchmarked against RRT*,GoalBiased RRT*,and APF-RRT*,and demonstrates significantly faster convergence,lower path-energy consumption,and enhanced safety margins. 展开更多
关键词 RRT* APF path planning OFF-ROAD Unmanned ground Vehicle(UGV)
在线阅读 下载PDF
HCL Net: Deep Learning for Accurate Classification of Honeycombing Lung and Ground Glass Opacity in CT Images
9
作者 Hairul Aysa Abdul Halim Sithiq Liyana Shuib +1 位作者 Muneer Ahmad Chermaine Deepa Antony 《Computers, Materials & Continua》 2026年第1期999-1023,共25页
Honeycombing Lung(HCL)is a chronic lung condition marked by advanced fibrosis,resulting in enlarged air spaces with thick fibrotic walls,which are visible on Computed Tomography(CT)scans.Differentiating between normal... Honeycombing Lung(HCL)is a chronic lung condition marked by advanced fibrosis,resulting in enlarged air spaces with thick fibrotic walls,which are visible on Computed Tomography(CT)scans.Differentiating between normal lung tissue,honeycombing lungs,and Ground Glass Opacity(GGO)in CT images is often challenging for radiologists and may lead to misinterpretations.Although earlier studies have proposed models to detect and classify HCL,many faced limitations such as high computational demands,lower accuracy,and difficulty distinguishing between HCL and GGO.CT images are highly effective for lung classification due to their high resolution,3D visualization,and sensitivity to tissue density variations.This study introduces Honeycombing Lungs Network(HCL Net),a novel classification algorithm inspired by ResNet50V2 and enhanced to overcome the shortcomings of previous approaches.HCL Net incorporates additional residual blocks,refined preprocessing techniques,and selective parameter tuning to improve classification performance.The dataset,sourced from the University Malaya Medical Centre(UMMC)and verified by expert radiologists,consists of CT images of normal,honeycombing,and GGO lungs.Experimental evaluations across five assessments demonstrated that HCL Net achieved an outstanding classification accuracy of approximately 99.97%.It also recorded strong performance in other metrics,achieving 93%precision,100%sensitivity,89%specificity,and an AUC-ROC score of 97%.Comparative analysis with baseline feature engineering methods confirmed the superior efficacy of HCL Net.The model significantly reduces misclassification,particularly between honeycombing and GGO lungs,enhancing diagnostic precision and reliability in lung image analysis. 展开更多
关键词 Deep learning honeycombing lung ground glass opacity Resnet50v2 multiclass classification
在线阅读 下载PDF
Amplification of thickness and stratigraphy of loess deposit on seismic ground motion in the Yellow River Basin
10
作者 Huijuan Wang Jinghua Zhang Ping Wang 《Earthquake Science》 2026年第1期32-50,共19页
The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion p... The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion parameters,directly influencing the regional seismic hazard risk level.This study methodically conducted on-site studies and observations of building collapses and damages resulting from seismic amplification effects,using the Wenchuan M_(S)8.0 earthquake as a case study.Comprehensive experimental and numerical simulation studies were carried out.A large-scale shaking table test was performed,and numerical models for 14 different loess sites types were established.Various types of seismic waves were incorporated into these models for systematic numerical simulation calculations.The research reveals the mechanisms by which loess deposit thickness and stratigraphic structure in the Yellow River Basin affect seismic ground motion amplification.The results indicate that as the epicentral distance increases,the peak ground motion shows a marked attenuation trend,with the horizontal component attenuating substantially faster than the vertical component.As the overlying loess layer thickness increases from 50 to 100 m,the seismic intensity may escalate by 3−4 degrees,and the peak acceleration may amplify by 1.5−2.2 times.With the augmentation of loess deposit thickness and the proliferation of soil layers,both the peak acceleration response spectrum and the characteristic period demonstrate an upward tendency,exhibiting slight fluctuations contingent upon the seismic wave type. 展开更多
关键词 Yellow River Basin loess deposits stratigraphic structure seismic ground motion amplification shaking table test
在线阅读 下载PDF
Experimental and theoretical investigation of face failure and ground collapse during slurry pressure-balanced shield tunneling in saturated sand
11
作者 Mengzhe Huo Weizhong Chen +3 位作者 Jingqiang Yuan Yunfa Li Yubiao Liu Qun Sui 《Journal of Rock Mechanics and Geotechnical Engineering》 2026年第2期1320-1336,共17页
Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoret... Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis. 展开更多
关键词 Slurry shield model test Saturated sand ground collapse Tunnel face stability Rotational failure mechanism
在线阅读 下载PDF
Analysis of Chinese/English Codeswitching on Network Language by Figure/ground Theory
12
作者 马玉波 《中国校外教育》 2011年第6期42-42,122,共2页
With the rapid development of network language,more and more phenomena of Chinese/English Codeswitching appear in our daily communications.Codeswitching research of the network language is a new aspect in the linguist... With the rapid development of network language,more and more phenomena of Chinese/English Codeswitching appear in our daily communications.Codeswitching research of the network language is a new aspect in the linguistic field.The paper starts from cognitive perspective to discuss the process of Chinese/English Codeswitching by Figure/ground theory. 展开更多
关键词 网络语言 言语交际 语码转换 汉语 英语
在线阅读 下载PDF
Ground motion,liquefaction and hazard analysis at the Palu site during the 2018 Indonesian great earthquake(M_(w)7.5)
13
作者 Lindung Zalbuin Mase Weeradetch Tanapalungkorn +2 位作者 Suched Likitlersuang Kyohei Ueda Tetsuo Tobita 《China Geology》 2026年第1期152-174,共23页
The research findings on the ground motion and liquefaction potential analyses during the 2018 Great Indonesia Earthquake(M_(w)7.5)are significant and crucial.The earthquake triggered soil-structure damage due to liqu... The research findings on the ground motion and liquefaction potential analyses during the 2018 Great Indonesia Earthquake(M_(w)7.5)are significant and crucial.The earthquake triggered soil-structure damage due to liquefaction.This study,which thoroughly investigated four sites at Palu,was conducted by performing a comprehensive ground motion parameter analysis.The ground motion characteristics were presented and justified,particularly for the most impacted direction.Ground motion predictions were analysed to define the spectral accelerations,and matching spectral accelerations were conducted to produce ground motions for each site.Non-linear seismic ground response analysis based on the hyperbolic model of pressure pressure-dependent was performed to investigate cyclic soil behaviour.The results revealed that ground motion is crucial in significant soil damage,and the earthquake energy could trigger deep liquefaction.As the most significant ground motion,the vertical ground motion is essential in determining deep liquefaction.The discussion on the impact of liquefaction based on the results of the numerical analysis is presented.Significant ground motion with a longer duration could have a substantial impact on deep liquefaction in the study area.These findings depict how the 2018 Indonesia Earthquake(M_(w)7.5)triggered a mega-liquefaction in Palu City.The results could enhance the understanding of the importance of seismic hazard assessment.It is recommended that site investigation and soil improvement should be planned to counteract liquefaction damage before construction.This study also suggests conducting seismic hazard assessments for city development to minimise the potential disaster impact in the study area. 展开更多
关键词 Shallow earthquake(Mw 7.5) ground motion LIQUEFACTION Spectral matching method Seismic Hazard Assessment Structure damage
在线阅读 下载PDF
Cognitive Stylistic Study on Cummings's Love Lyrics——Based on Figure-Ground Theory
14
作者 方圆圆 《海外英语》 2017年第8期161-163,共3页
The style of Cummings' s poems is unique and special among the 20 th century poets. In this thesis, his love lyrics are analyzedfrom cognitive stylistics perspective and this analysis is based on the figure-ground... The style of Cummings' s poems is unique and special among the 20 th century poets. In this thesis, his love lyrics are analyzedfrom cognitive stylistics perspective and this analysis is based on the figure-ground theory. According to Talmy's classification of lan-guage events, Cummings' s love lyrics are divided into space events and time events. Then figure and ground in different poems are de-termined on the basis of features and principles of figure and ground in two kinds of events. The analysis makes it possible for readers tobuild an interest in Cummings' s love lyrics and identify the hidden emotions and contents. What's more, connotation as well as aesthet-ic values of poems can also be explored. Theory in the cognitive stylistics is applied to the appreciation of poems in this paper, whichmay help readers imagine the scene and better understand the connotation. This method provides a new perspective for poem study.Meanwhile, it offers a new pedagogical method in poem teaching in the future. 展开更多
关键词 figure-ground theory cognitive stylistics E CUMMINGS love lyrics
在线阅读 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
15
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
在线阅读 下载PDF
Breath Figure法制备聚碳酸酯(PC)蜂窝状多孔膜 被引量:3
16
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
在线阅读 下载PDF
Relationship Between Noise Figure and Equivalent Input Noise Current Spectral Density for Optical Receiver Design 被引量:1
17
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
在线阅读 下载PDF
Lichtenberg Figures 技术的新应用 被引量:2
18
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
在线阅读 下载PDF
利用Breath Figures法制备具有蜂窝状结构的PMMA/TBT复合膜
19
作者 申延明 刘东斌 +1 位作者 刘丹 刘雅祺 《高分子学报》 SCIE CAS CSCD 北大核心 2011年第3期261-266,共6页
以聚甲基丙烯酸甲酯(PMMA)和钛酸四丁酯(TBT)的氯仿溶液为铸膜溶液,采用Breath Figures法制备了蜂窝状结构的PMMA/TBT多孔阵列薄膜,采用SEM、IR、XRD对制备的多孔膜进行了表征,探讨了聚合物浓度、PMMA/TBT配比以及水解抑制剂对膜蜂窝状... 以聚甲基丙烯酸甲酯(PMMA)和钛酸四丁酯(TBT)的氯仿溶液为铸膜溶液,采用Breath Figures法制备了蜂窝状结构的PMMA/TBT多孔阵列薄膜,采用SEM、IR、XRD对制备的多孔膜进行了表征,探讨了聚合物浓度、PMMA/TBT配比以及水解抑制剂对膜蜂窝状结构的影响.实验结果表明,起始溶液浓度为20~30mg/mL,PMMA/TBT配比大于3时可以得到结构完好的蜂窝状结构.在起始铸膜溶液中添加异丙醇可以提高成膜的效果,减小蜂窝状结构的孔径.IR、XRD分析结果表明,成膜过程中TBT发生了部分水解,形成了氢化氧化钛水合物. 展开更多
关键词 BREATH figures 有序多孔膜 蜂窝状结构 有机/无机复合膜
原文传递
Figure-9腔锁模全保偏掺铒光纤飞秒激光器 被引量:1
20
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
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部