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Allozyme Diversity and Population Genetic Structure of Three Medicinal Epimedium Species from Hubei 被引量:4
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作者 徐艳琴 李作洲 +1 位作者 王瑛 黄宏文 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第1期56-71,共16页
Three Epimedium species, E. pubescens Maxim., E. sagittatum (Sieb. & Zucc.) Maxim., and E. wushanense T. S. Ying, which are sympatrically distributed in the western Hubei Province, have been used in traditional Chi... Three Epimedium species, E. pubescens Maxim., E. sagittatum (Sieb. & Zucc.) Maxim., and E. wushanense T. S. Ying, which are sympatrically distributed in the western Hubei Province, have been used in traditional Chinese medicine (TCM) for about 2,000 years. Genetic variability and population genetic structure of 11 natural populations of these Epimedium species were investigated using isoelectric focusing in thin-layer polyacrylamide slab gels. Of the 22 enzyme systems prescreened, six coding for 13 loci and 45 alleles were resolved, which were used for analyzing genetic diversity and population structure at both intraspecific and interspecific levels. The results showed that: l) high levels of genetic diversity were observed in all three species (A = 2.6-3.2, P = 69.2%-84.6%, Ho= 0.274-0.377, HE= 0.282-0.369), which were higher than that of other herbaceous and aulmal-pollinated species with similar life-history characteristics; 2) there was significant deviation from Hardy-Weinberg Equilibrium, with one half of the loci showing heterozygote excess and the other homozygote excess, in all populations, suggesting the complicated breeding system of Epimedium species; 3) the low level of intraspecific and interspecific genetic differentiation (GST= 0.0246-0.0409 and 0.0495-0.1213, respectively) indicated a high level of gene flow among populations and close genetic relationship among the three species; and 4) UPGMA cluster analysis further showed that E. pubescens was more closely related to E. sagittatum than to E. wushanense, which was in good agreement with the morphological characters and the recent phylogenetic analysis of these species. On the basis of these results, it was concluded that the mixed breeding system, long-lived perennial life form, ancient evolutionary history, and seed dispersal by ants in Epimedium are responsible for the genetic variation and population structure of these species. 展开更多
关键词 Epimedium pubescens Maxim. E. sagittatum (Sieb. Zucc.) Maxim. E. wushanense T. S. Ying ALLOZYME genetic diversity population structure
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Microstructure and mechanical properties of TiAl-based alloy prepared by double mechanical milling and spark plasma sintering 被引量:3
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作者 肖树龙 徐丽娟 +1 位作者 陈玉勇 于宏宝 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第5期1086-1091,共6页
A fine-grained TiAl alloy with a composition of Ti-45Al-2Cr-2Nb-1B-0.5Ta-0.225Y (mole fraction, %) was prepared by double mechanical milling(DMM) and spark plasma sintering(SPS). The relationship among sintering... A fine-grained TiAl alloy with a composition of Ti-45Al-2Cr-2Nb-1B-0.5Ta-0.225Y (mole fraction, %) was prepared by double mechanical milling(DMM) and spark plasma sintering(SPS). The relationship among sintering temperature, microstructure and mechanical properties was studied. The results show that the morphology of double mechanical milled powder is regular with size in the range of 20-40 μm and mainly composed of TiAl and Ti3Al phases. The main phase TiAl and few phases Ti3Al, Ti2Al and TiB2 were observed in the SPSed alloys. For samples sintered at 900 ℃ the equiaxed crystal grain microstructure is achieved with size in the range of 100-200 nm. With increasing the SPS temperature from 900 ℃to 1000 ℃ the size of equiaxed crystal grain obviously increases, the microhardness decreases from HV658 to HV616, and the bending strength decreases from 781 MPa to 652 MPa. In the meantime, the compression fracture strength also decreases from 2769 MPa to 2669 MPa, and the strain to fracture in compression increases from 11.69% to 17.76%. On the base of analysis of fractographies, it shows that the compression fracture transform of the SPSed alloys is intergranular rupture. 展开更多
关键词 TiAl-based alloys mechanical alloying spark plasma sintering MICROSTRUCTURE mechanical properties
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河南省第三产业发展的制约因素
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《市场研究》 2001年第4期4-5,共2页
河南第三产业发展中存在的总量不足,比重偏低,对经济增长推动乏力,以及所有制结构、行业结构、城乡结构、地区分布等结构性偏差,原因是多方面的,既有体制、政策方面的因素,也和河南经济发展的整体状况密切相关。
关键词 第三产业发展 第三产业部门 河南经济 产业政策 制约因素 河南省 第三产业增加值 第二产业 行业结构 等结构性
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Design and Realization of CPW Circuits Using EC-ANN Models for CPW Discontinuities
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作者 胡江 孙玲玲 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第12期2320-2329,共10页
Novel accurate and efficient equivalent circuit trained artificial neural-network (EC-ANN) models,which inherit and improve upon EC model and EM-ANN models' advantages,are developed for coplanar waveguide (CPW) d... Novel accurate and efficient equivalent circuit trained artificial neural-network (EC-ANN) models,which inherit and improve upon EC model and EM-ANN models' advantages,are developed for coplanar waveguide (CPW) discontinuities. Modeled discontinuities include : CPW step, interdigital capacitor, symmetric cross junction, and spiral inductor, for which validation tests are performed. These models allow for circuit design, simulation, and optimization within a CAD simulator. Design and realization of a coplanar lumped element band pass filter on GaAs using the developed CPW EC-ANN models are demonstrated. 展开更多
关键词 CPW DISCONTINUITIES MODELS equivalent circuit artificial neural-network band pass filter
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Effect of high-voltage discharge non-thermal plasma on g-C_3N_4 in a plasma-photocatalyst system 被引量:3
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作者 Xiaoping Wang Yixia Chen +2 位作者 Min Fu Zihan Chen Qiulin Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第10期1672-1682,共11页
The synergistic effect of high voltage discharge non‐thermal plasma(NTP)and photocatalysts on contaminant removal has repeatedly confirmed by plenty of researches.Most previous plasma‐photocatalyst synergistic syste... The synergistic effect of high voltage discharge non‐thermal plasma(NTP)and photocatalysts on contaminant removal has repeatedly confirmed by plenty of researches.Most previous plasma‐photocatalyst synergistic systems focused on the utilization of the ultraviolet light but ignored the visible light generated by high voltage discharge.Graphitic carbon nitride(g‐C3N4),a metal‐free semiconductor that exhibits high chemical stability,can utilize both the ultraviolet and visible light from high voltage discharge.However,the synergistic system of NTP and g‐C3N4 has been researched little.In this paper,the effect of NTP generated by dielectric barrier discharge(DBD)on g‐C3N4 is studied by comparing the photocatalytic activities,the surface physical structure and the surface chemical characteristics of pristine and plasma treated g‐C3N4.Experimental results indicate that the DBD plasma can change the physical structure and the chemical characteristics and to further affect the photocatalytic activity of g‐C3N4.The effect of NTP on g‐C3N4 is associated with the discharge intensity and the discharge time.For a long time scale,the effect of NTP on g‐C3N4 photocatalysts presents a periodic change trend. 展开更多
关键词 g‐C3N4 Non‐thermal plasma Photocatalytic activity Physical structure Chemical characteristic
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Enhanced stability of highly-dispersed copper catalyst supported by hierarchically porous carbon for long term selective hydrogenation 被引量:2
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作者 Nian Hu Xiao-Yun Li +7 位作者 Si-Ming Liu Zhao Wang Xiao-Ke He Yue-Xin Hou Yu-Xiang Wang Zhao Deng Li-Hua Chen Bao-Lian Su 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1081-1090,共10页
Copper based catalysts have high potential for the substituent of noble-metal based catalysts as their high selectivity and moderate activity for selective hydrogenation reaction;however,achieving further high catalyt... Copper based catalysts have high potential for the substituent of noble-metal based catalysts as their high selectivity and moderate activity for selective hydrogenation reaction;however,achieving further high catalytic stability is very difficult.In this work,the carbonization process of Cu-based organic frameworks was explored for the synthesis of highly-dispersed Cu supported by hierarchically porous carbon with high catalytic performance for selective hydrogenation of 1,3-butadiene.The porous hierarchy of carbon support and the dispersion of copper nanoparticles can be precisely tuned by controlling the carbonization process.The resultant catalyst carbonized at 600°C exhibits a rather low reaction temperature at 75°C for 100%butadiene conversion with 100%selectivity to butenes,due to its reasonable porous hierarchy and highly-dispersed copper sites.More importantly,unprecedentedly stability of the corresponding Cu catalyst was firstly observed for selective 1,3-butadiene hydrogenation,with both 100%butadiene conversion and 100%butenes selectivity over 120 h of reaction at 75°C.This study verifies that a simply control the carbonization process of metal organic frameworks can be an effective way to obtain Cu-based catalysts with superior catalytic performance for selective hydrogenation reaction. 展开更多
关键词 Hierarchically porous structure CATALYST Cu/C Selective hydrogenation Metal organic frameworks
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Effect of Particle's Size on the Structural and Dynamical Properties in 2D Dusty Plasma 被引量:1
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作者 KONG Wei WANG Xin +2 位作者 LIU Song-Fen HU Bei-Lai WANG Long 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期569-572,共4页
In a two-dimensional (219) dusty plasma system, the size of particles is considered under two different interparticle potentials (Yukawa potential and Dressed potential). The structural and dynamical characters a... In a two-dimensional (219) dusty plasma system, the size of particles is considered under two different interparticle potentials (Yukawa potential and Dressed potential). The structural and dynamical characters are investigated by molecular dynamics simulation respectively. The results show that the 2D systems via Yukawa and Dressed potentials have a different critical coupling constant F corresponding to the systems beginning to coagulate and exhibit different crystal configurations. Also we find that the size of particles has little influence on the 2D system's structure characters. 展开更多
关键词 2D dusty plasma Yukawa potential dressed potential
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Equivalent Bar Conceptions for Computer Analysis of Pantographic Foldable Structures
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作者 陈务军 付功义 +1 位作者 何艳丽 董石麟 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第1期80-84,共5页
An equivalent bar conception is firstly developed for the computer analysis of pantographic foldable structures. The uniplet of two three node beam elements is assumed as a six bar assembly with respect to least norm ... An equivalent bar conception is firstly developed for the computer analysis of pantographic foldable structures. The uniplet of two three node beam elements is assumed as a six bar assembly with respect to least norm least square solution for the elastic strain energy equality. The equilibrium equation is developed for the equivalent models, and the internal forces formulated sequently for backup calculation. This procedure is proved practical for some engineering, and some interesting concepts proposed. Finally, three numerical tests are presented. 展开更多
关键词 pantographic structure equivalent bar conception stiffness matrix
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Vector and Spinor Decomposition of SU(2) Gauge Potential, Their Equivalence, and Knot Structure in SU(2) Chern-Simons Theory
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作者 DUAN Yi-Shi REN Ji-Rong LI Ran 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5期875-878,共4页
In this paper, spinor and vector decompositions of SU(2) gauge potential are presented and their equivalence is constructed using a simply proposal. We also obtain the action of Faddeev nonlinear 0(3) sigma model ... In this paper, spinor and vector decompositions of SU(2) gauge potential are presented and their equivalence is constructed using a simply proposal. We also obtain the action of Faddeev nonlinear 0(3) sigma model from the SU(2) mass/ve gauge field theory, which is proposed according to the gauge invariant principle. At last, the knot structure in SU(2) Chern-Simons filed theory is discussed in terms of the Φ-mapping topological current theory, The topological charge of the knot is characterized by the Hopf indices and the Brouwer degrees of Φ-mapping. 展开更多
关键词 SU(2) gauge potential decomposition massive gauge theory CHERN-SIMONS KNOT
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Structure of Macro- and Trace Elements Status Observed in Residents of Magadan Town
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作者 Lugovaya Elena Stepanova Evgenia 《Journal of Life Sciences》 2014年第9期794-797,共4页
The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age (21-35) residing in Magadan town to assess the content of 25 trace elements in hair samples ... The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age (21-35) residing in Magadan town to assess the content of 25 trace elements in hair samples on individual and population levels by atom-emission spectrometry with inductively-bonded argon plasma. It turned out that the majority of surveyed subjects were characterized by deformation of element status demonstrated by excess and deficit of the basic essential elements of different degrees of manifestation. Deficit of Co (68% of surveyed people), Mg (67%), Ca (64%), Cu (47%), K (46%), Zn (44%), I (41%), Na (33%), P (27%) and Se (24%) was typical for female subjects as well as excess of Si (28%), Zn (22%) and P (20%). Male residents were characterized by deficit of Co (81%), Ca (66%), Mg (65%), I (50%), Cu (37%), K and Na (27%) and excess of Zn (41%). In individual cases it was noted excess concentration of nominally essential and toxic elements in both examined groups. They were: A1, As, Cd, Li, Ni, Pb, Sn, V and B. While analyzing of medians of chemical concentration it was stated reliable sex-related differences (P 〈 0.05): content of Ca, Mg and Mn was higher in hair samples of women, and content of As, B, Cd, Cr, K, Li, Na, P, Pb and V, on the contrary, was higher in male samples. 展开更多
关键词 Macro- and trace elements misbalance the North MEN women.
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Supply-Side Structural Reform in the Service Industry and Escaping the Middle Income Trap 被引量:1
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作者 Zhang Jianhua Cheng Wen Gong Huayan 《Social Sciences in China》 2021年第1期77-96,共20页
The internal consumption and production structure of the service industry that now dominates the Chinese economy needs to be optimized.Introducing supply-side structural reform to improve the in-depth integration of a... The internal consumption and production structure of the service industry that now dominates the Chinese economy needs to be optimized.Introducing supply-side structural reform to improve the in-depth integration of advanced manufacturing and the modern service industry and promoting a strong domestic market is the key to escaping the middle income trap.We use 1950-2010 data from 45 non-oil-exporting economies representing the structural evolution of the service industry worldwide to compare Asian economies that have passed through the middle income trap with Latin American counterparts that remain stuck in the trap,and thence proceed to construct a matched model that covers the consumption and production service industries and their supply of human capital,with the aim of identifying the formative mechanisms and conditions for escaping the middle income trap through upgrading the structure of the service industry.Substantially developing the production service sector,raising the supply of public services so as to cultivate the quantity and quality of human capital,and matching senior-level human capital with knowledge-intensive serviceindustries will propel the upgrading and transformation of China’s economic structure toward high-quality development. 展开更多
关键词 production service industries consumption service industries middle income trap supply-side structural reform
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Equivalent Stochastic Linearization for Nonlinear Uncertain Structure Under Stationary Gaussian Stochastic Excitation
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作者 刘勇 陈炉云 易宏 《Journal of Shanghai Jiaotong university(Science)》 EI 2014年第1期123-128,共6页
Equivalent stochastic linearization (ESL) for nonlinear uncertain structure under stationary stochastic excitation is presented. There are two parts of difference between the original system and equivalent system: ... Equivalent stochastic linearization (ESL) for nonlinear uncertain structure under stationary stochastic excitation is presented. There are two parts of difference between the original system and equivalent system: one is caused by the difference between the means of original and equivalent stochastic structure; and another is caused by the difference between the original and equivalent stochastic structure which has the relation with stochastic variables. Statistical characteristics of equivalent stochastic structure can be obtained in accordance with mean square criterion, so nonlinear stochastic structure is transformed into linear stochastic structure. In order to attain that objective, the compound response spectrum of linear stochastic structure under stationary random excitation which is used in the solution is derived in the case of the mutual independence between stochastic excitation and stochastic structure. Finally, the example shows the accuracy and validity of the proposed method. 展开更多
关键词 equivalent stochastic linearization nonlinear stochastic structure pseudo excitation method
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ON A KIND OF GENERALIZED QUASI-VARIATIONAL INEQUALITIES AND FAN's MINIMAX INEQUALITY WITHOUT CONVEXITY
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作者 SHENZIFEI WUXIAN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2001年第3期337-342,共6页
This Paper gives a Fan’s type minimax theorem, a nearest point theorem and two existence theorems of solutions for a kind of generalized quasi-variational inequalities in H-spaces without any linear structure.
关键词 Locally convex H-space H-convex set Acyclic set Almost upper semi- continuous multivalued mapping
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Nonlinear Structures in an Ion-Beam Plasmas Including Dust Impurities with Nonthermal Nonextensive Electrons
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作者 Debjit Dutta Biswajit Sahu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第7期117-124,共8页
The properties of dust ion acoustic waves are investigated in an unmagnetized multicomponent plasma system consisting of ion beam, charged positive and negative ions, electrons obeying nonthermal-Tsallis distribution ... The properties of dust ion acoustic waves are investigated in an unmagnetized multicomponent plasma system consisting of ion beam, charged positive and negative ions, electrons obeying nonthermal-Tsallis distribution and stationary negatively charged dust grains by the conventional Sagdeev pseudopotential method, through which the condition for existence of several nonlinear structures is analyzed theoretically. The dispersion relation for electrostatic waves is derived and analyzed and an expression of the energy integral equation is obtaJned. It is reported here that our plasma model supports solitions, double layers and supersoliton solutions for certain range of parameters. Finally, the effects of different physical plasma parameters on these nonlinear structures are studied numerically. The present theory should be helpful in understanding the salient features of the electrostatic waves in space and in laboratory plasmas where two distinct groups of ions and non-Maxwellian distributed electrons are present. 展开更多
关键词 multicomponent plasma dust ion acoustic waves solitons and supersolitons
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Nonlinear Structures of Lower Hybrid Wave in Collision Plasmas
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作者 黄凤 严飞 +2 位作者 王影 徐金荣 陈含爽 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第1期83-86,共4页
Nonlinear structures of lower hybrid wave in collision plasmas are studied using the two-fluid theory.The oscillatory shock wave is observed due to the effects of the electron-neutral collision and the density inhomog... Nonlinear structures of lower hybrid wave in collision plasmas are studied using the two-fluid theory.The oscillatory shock wave is observed due to the effects of the electron-neutral collision and the density inhomogeneity.In the cold electron limit,the oscillatory shock wave becomes the ordinary shock wave.In the collisionless limit,the dominated equation becomes Kd V equation and the lower hybrid solitons arise.The amplitude of the nonlinear structure is depressed by the plasma inhomogeneity,but is hardly affected by the electron-neutral collision. 展开更多
关键词 lower hybrid wave shock wave SOLITON collision plasmas
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Extreme Ultraviolet Sources Generation by Using the Two-Color Multi-Cycle Weak Inhomogeneous Field
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作者 冯立强 李文亮 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第1期86-90,共5页
An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicin... An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicinity of metallic nanostructures. The results show that by properly choosing the inhomogeneity of the two-color multi-cycle(20 fs) weak pulse(1013W/cm2), not only the harmonic cutoff has been extended, resulting in a broadband XUV continuum, but also the single short quantum path has been selected to contribute to the harmonic. As a result, two isolated XUV pulses with durations of 68 as and 66 as can be obtained. 展开更多
关键词 high-order harmonic generation attosecond pulse multi-cycle pulse plasmonic field enhancement
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Nonlinear dynamic characteristics of magneto-rheological visco-elastomers 被引量:4
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作者 YING ZuGuang NI YiQing SAJJADI Masoud 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第4期878-883,共6页
The smart magneto-rheological visco-elastomer (MRVE) has a promising application to vibration control.Its dynamic characteristics are described by complex moduli which are applicable to linear dynamics.However,experim... The smart magneto-rheological visco-elastomer (MRVE) has a promising application to vibration control.Its dynamic characteristics are described by complex moduli which are applicable to linear dynamics.However,experimental results show remarkable nonlinear relations between force and deformation for certain large deformations,and the nonlinear dynamic modeling needs to be developed.The present study focuses on the nonlinear dynamic characteristics of MRVE.The MRVE was fabricated and specimens were tested to show nonlinear mechanical properties and dynamic behaviors.The nonlinear effect induced by applied magnetic fields was investigated.A phenomenological model for the dynamic behaviors of MRVE was proposed to describe the nonlinear elasticity,linear damping and hysteretic effect,and the corresponding equivalent linear model in the frequency domain was also given for small deformations.The proposed model is applicable to the dynamics and control analysis of composite structures with MRVE. 展开更多
关键词 nonlinear hysteresis dynamic modeling magneto-rheological visco-elastomer complex stiffness
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Physical characteristics with SPP in the metallic nanowires structure
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作者 ZHU Jun LI ZhiQuan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第10期1776-1780,共5页
In this work, the terahertz (THz) electromotive force (EMF) of the surface plasmon (SP) electric field and field strength was investigated in its propagation direction. Based on the nanowires structure, we intro... In this work, the terahertz (THz) electromotive force (EMF) of the surface plasmon (SP) electric field and field strength was investigated in its propagation direction. Based on the nanowires structure, we introduced physical models which were light wave energy of surface plasmon polariton (SPP) pulse and the variation of EMF changes in the active condition. Results of theory and verification showed SPP generated EMF with 10-2-10 V among wire radii of 5-30 nm; the electric field was up to 10^5-1066V/cm in the radius of 5 nm; the electric field intensity induced localization at λ=850 nm, and at the same time light intensity amplified 40 times. The characteristics which are femtosecond SPP pulse response and force-field amplifier in this work are significant for nonlinear spectroscopy research. 展开更多
关键词 nonlinear optical surface plasmon polariton (SPP) THz frequency energy amplification
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