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Acoustic anechoic layers with singly periodic array of scatterers: Computational methods, absorption mechanisms, and optimal design 被引量:7
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作者 杨海滨 李岳 +2 位作者 赵宏刚 温激鸿 温熙森 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期283-291,共9页
The acoustic properties of anechoic layers with a singly periodic array of cylindrical scatterers are investigated. A method combined plane wave expansion and finite element analysis is extended for out-of-plane incid... The acoustic properties of anechoic layers with a singly periodic array of cylindrical scatterers are investigated. A method combined plane wave expansion and finite element analysis is extended for out-of-plane incidence. The reflection characteristics of the anechoic layers with cavities and locally resonant scatterers are discussed. The backing is a steel plate followed by an air half space. Under this approximate zero transmission backing condition, the reflection reduction is induced by the absorption enhancement. The absorption mechanism is explained by the scattering/absorption cross section of the isolated scatterer. Three types of resonant modes which can induce efficient absorption are revealed. Due to the fact that the frequencies of the resonant modes are related to the size of the scatterers, anechoic layers with scatterers of mixed size can broaden the absorption band. A genetic optimization algorithm is adopted to design the anechoic layer with scatterers of mixed size at a desired frequency band from 2 kHz to l0 kHz for normal incidence, and the influence of the incident angle is also discussed. 展开更多
关键词 acoustic anechoic layer resonant scattering resonant absorption singly periodic mixed size
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Low noise,continuous-wave single-frequency 1.5-μm laser generated by a singly resonant optical parametric oscillator 被引量:3
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作者 刘建丽 刘勤 +2 位作者 李宏 李鹏 张宽收 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第11期312-316,共5页
We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was ... We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was pumped by a CW single-frequency Nd:YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit (SNL) at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz. 展开更多
关键词 singly resonant optical parametric oscillator 1.5-μm laser single-frequency operation low noise
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Λ_(c)^(+)→Λh^(+)和Λc+→∑^(0)h^(+)(h=K,π)衰变道CP破坏的寻找和其分支比与衰变不对称参数的测量
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作者 Belle合作组 L.K.Li 《Science Bulletin》 SCIE EI CAS CSCD 2023年第6期583-592,M0004,共11页
本文报告了粲重子Λ_(c)^(+)的四个弱衰变道Λ_(c)^(+)→Λh^(+)和Λ_(c)^(+)→∑^(0)h^(+)(h=K,π)的系列研究.基于在KEKB能量不对称的正负电子对撞机上的Belle探测器收集的980 fb-1数据样本,作者测量了粲重子两体单卡比玻压低(SCS)衰... 本文报告了粲重子Λ_(c)^(+)的四个弱衰变道Λ_(c)^(+)→Λh^(+)和Λ_(c)^(+)→∑^(0)h^(+)(h=K,π)的系列研究.基于在KEKB能量不对称的正负电子对撞机上的Belle探测器收集的980 fb-1数据样本,作者测量了粲重子两体单卡比玻压低(SCS)衰变过程中的直接电荷共轭-宇称(CP)不对称:ACPdir(Λ_(c)^(+)→ΛK^(+))=+0.021±0.026±0.001和ACPdir(Λ_(c)^(+)→∑^(0)K^(+))=+0.025±0.054±0.004;精确测量了衰变不对称参数(α)和其引起的CP不对称度:AC^(α)_(P)(Λ_(c)^(+)→ΛK^(+))=-0.023±0.086±0.071和AC^(α)_(P)(Λ_(c)^(+)→∑^(0)K^(+))=+0.08±0.035±0.14.这是粲重子SCS衰变的第一个AC^(α)_(P)结果;其次,作者在实验上利用粲重子衰变来寻找超子CP破坏,即利用Λ_(c)^(+)→(Λ,∑^(0))π^(+)衰变获得AC^(α)_(P)(Λ→pπ-)=+0.013±0.007±0.011.以上测量均未发现重子CP破坏的证据.此外,该文还报告了Λ_(c)^(+)两个SCS衰变道的分支比测量:B(Λ_(c)^(+)-ΛK^(+))=(6.57±0.17±0.11±0.35)×10^(-4)和B(Λ_(c)^(+)→∑^(0)K^(+))=(3.58±0.19±0.06±0.19)×10^(-4),这些均为目前最精确的结果. 展开更多
关键词 CP violation Charmed baryon singly Cabibbo-suppressed decay Branching fraction Decay asymmetry parameter CP asymmetry
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Heavy flavor baryon spectra via QCD sum rules
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作者 张建荣 黄明球 《Chinese Physics C》 SCIE CAS CSCD 2009年第12期1385-1388,共4页
In this talk, we give a short review of our recent works on studying the singly heavy baryon, doubly heavy baryon, and triply heavy baryon Spectra from QCD sum rules.
关键词 singly heavy baryon doubly heavy baryon triply heavy baryon QCD sum rules
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A tunable yellow emission from three-band emission of singly doped single-phased phosphor BaY_2S_4:Ho^(3+)
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作者 赵君风 陈茜 +2 位作者 荣春英 余丽萍 廉世勋 《Journal of Rare Earths》 SCIE EI CAS CSCD 2011年第5期436-439,共4页
The establishment of an approach to design tunable yellow emission through singly doped single-phased phosphors to obtain white LED-based InGaN chip was reported. BaY2–xS4:xHo3+ phosphors were prepared by the high ... The establishment of an approach to design tunable yellow emission through singly doped single-phased phosphors to obtain white LED-based InGaN chip was reported. BaY2–xS4:xHo3+ phosphors were prepared by the high temperature solid state reaction and characterized by X-ray diffraction and photoluminescence spectra. Under the excitation of 465 nm,the emission spectra of these phosphors exhibited three sharp emission lines peaked at about 492,543 and 661 nm of Ho3+ corresponding to 5F3,5F4 (5S2) and 5F5→5I8 transitions,respectively,with comparable intensities,resulting in a yellow light emission. The luminescence mechanism for Ho3+ in BaY2S4 was explained. 展开更多
关键词 rare earths BaY2S4:Ho3+ yellow emission singly doped single-phased phosphor
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Singly Covered Minimal Elements of Linked Partitions and Cycles of Permutations
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作者 Guo Wen-kui Niu Fei-fei Du Xian-kun 《Communications in Mathematical Research》 CSCD 2019年第1期75-80,共6页
Linked partitions were introduced by Dykema(Dykema K J. Multilinear function series and transforms in free probability theory. Adv. Math., 2005, 208(1):351–407) in the study of the unsymmetrized T-transform in free p... Linked partitions were introduced by Dykema(Dykema K J. Multilinear function series and transforms in free probability theory. Adv. Math., 2005, 208(1):351–407) in the study of the unsymmetrized T-transform in free probability theory.Permutation is one of the most classical combinatorial structures. According to the linear representation of linked partitions, Chen et al.(Chen W Y C, Wu S Y J, Yan C H. Linked partitions and linked cycles. European J. Combin., 2008, 29(6): 1408–1426) de?ned the concept of singly covered minimal elements. Let L(n, k) denote the set of linked partitions of [n] with k singly covered minimal elements and let P(n, k) denote the set of permutations of [n] with k cycles. In this paper, we mainly establish two bijections between L(n, k) and P(n, k). The two bijections from a different perspective show the one-to-one correspondence between the singly covered minimal elements in L(n, k) and the cycles in P(n, k). 展开更多
关键词 singly COVERED MINIMAL element linked PARTITION PERMUTATION cycle
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Generation of self-oscillations from a singly resonant periodically poled potassium titanyl phosphate crystal frequency doubler
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作者 李渊骥 刘勤 +1 位作者 冯晋霞 张宽收 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第6期418-423,共6页
We report on the generation of self-oscillations from a continuously pumped singly resonant frequency doubler based on a periodically poled potassium titanyl phosphate crystal (PPKTP). The sustained square-wave and ... We report on the generation of self-oscillations from a continuously pumped singly resonant frequency doubler based on a periodically poled potassium titanyl phosphate crystal (PPKTP). The sustained square-wave and staircase curve of self-oscillations are obtained when the incident pump powers are below and above the threshold of subharmonic-pumped parametric oscillation (SPO), respectively. The self-oscillations can be explained by the competition between the phase shifts induced by cascading nonlinearity and thermal effect, and the influence of fundamental nonlinear phase shift by the generation of SPO. The simulation results are in good agreement with the experiment data. 展开更多
关键词 SELF-OSCILLATIONS singly resonant frequency doubler phase shift
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Bi-f-harmonic map equations on singly warped product manifolds
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作者 ZHAO Chun-li LU Wei-jun 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2015年第1期111-126,共16页
Bi-f-harmonic maps are the critical points of bi-f-energy functional. This class of maps tends to integrate bi-harmonic maps and f-harmonic maps. In this paper, we show that bi-f-harmonic maps are not only an extensio... Bi-f-harmonic maps are the critical points of bi-f-energy functional. This class of maps tends to integrate bi-harmonic maps and f-harmonic maps. In this paper, we show that bi-f-harmonic maps are not only an extension of f-harmonic maps but also an extension of bi-harmonic maps, and that there should exist many examples of proper bi-f-harmonic maps. In order to find some concrete examples of proper bi-f-harmonic maps, we study the basic properties of bi-f-harmonic maps from two directions which are conformal maps between the same dimensionM manifolds and some special maps from or into a warped product manifold. 展开更多
关键词 f-tension field bi-f-tension field bi-f-harmonic map f-bi-harmonic map singly warped productmanifold.
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Radiative decay from doubly to singly excited states of He via generalization of Laguerre-type orbitals: A non-orthogonal formalism
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作者 熊庄 Bacalis N C 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第2期374-381,共8页
By taking full account of the non-orthogonality of the orbitals between the low-lying doubly excited states ^1po and the singly excited states ^1S^e and ^1D^e of He, the corresponding radiative decay rates have been i... By taking full account of the non-orthogonality of the orbitals between the low-lying doubly excited states ^1po and the singly excited states ^1S^e and ^1D^e of He, the corresponding radiative decay rates have been investigated theoretically via analytic generalized Laguerre-type atomic orbitals at a nearly numerical multi-conflguration self-consistent field accuracy in a general non-orthogonal configuration interaction scheme. From these rates, we calculate the VUV photon emission and metastable atom spectra, and both are found to be in good qualitative agreement with recent excellent measurements. We obtain, successfully, the enhancement of the VUV photon spectrum, experimentally observed at the energy of (2s4p-4s2p)/(2p,3d) ^1po as compared with other nearby lying states. The mechanism proposed by Odling-Smee et al is verified, implying that taking appropriate account of the overlap existing between orbitals of the low-lying doubly excited and singly excited states (especially important for the compact orbitals) can reveal basic physical dominant mechanism and is crucial in understanding these spectra. 展开更多
关键词 doubly excited states singly excited states analytic basis functions non-orthogonality formalism
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Tm^(3+) and Nd^(3+) singly doped LiYF_4 single crystals with 3-5 μm mid-infrared luminescence 被引量:2
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作者 李珊珊 汪沛渊 +4 位作者 夏海平 彭江涛 唐磊 张约品 江浩川 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第2期54-56,共3页
Mid-infrared(MIR) emissions of 2.4 and 3.5 μm from Tm3+:LiYF4 single crystals attributed to3H4 →3H5 and3H5 →3F4 transitions as well as MIR emissions of 4.2,4.3,and 4.5 μm from Nd3+:LiYF4 lasers attributed to... Mid-infrared(MIR) emissions of 2.4 and 3.5 μm from Tm3+:LiYF4 single crystals attributed to3H4 →3H5 and3H5 →3F4 transitions as well as MIR emissions of 4.2,4.3,and 4.5 μm from Nd3+:LiYF4 lasers attributed to4I15/2 →4I13/2,4I13/2 →4I11/2,and4I11/2 →4I9/2 transitions,respectively,are observed.LiYF4 single crystals possess high transmittance of over 85% in the 2.5-6 μm range.The large emission crosssections of Tm-doped crystals at 2.4 μm(1.9×10-20cm2) and Nd-doped crystals at 4.2 μm(0.84×10-20 cm2) as well as the high rare-earth doping concentrations,excellent optical transmission,and chemicalphysical properties of the resultant samples indicate that Nd3+and Tm3+singly doped crystals may be promising materials for application in MIR lasers. 展开更多
关键词 and Nd MIR m mid-infrared luminescence singly doped LiYF4 single crystals with 3-5 TM
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Dynamic plastic response of clamped stiffened plates with large deflection 被引量:1
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作者 彭英 杨平 《Journal of Marine Science and Application》 2008年第2期82-90,共9页
Study on the dynamic response, and especially the nonlinear dynamic response of stiffened plates is complicated by their discontinuity and inhomogeneity. The finite element method (FEM) and the finite strip method are... Study on the dynamic response, and especially the nonlinear dynamic response of stiffened plates is complicated by their discontinuity and inhomogeneity. The finite element method (FEM) and the finite strip method are usually adopted in their analysis. Although many useful conclusions have been obtained, the computational cost is enormous. Based on some assumptions, the dynamic plastic response of clamped stiffened plates with large deflections was theoretically investigated herein by a singly symmetric beam model. Firstly, the deflection conditions that a plastic string must satisfy were obtained by the linearized moment-axial force interaction curve for singly symmetric cross sections and the associated plastic flow rule. Secondly, the possible motion mechanisms of the beam under different load intensity were analysed in detail. For structures with plastic deformations, a simplified method was then given that the arbitrary impact load can be replaced equivalently by a rectangular pulse. Finally, to confirm the validity of the proposed method, the dynamic plastic response of a one-way stiffened plate with four fully clamped edges was calculated. The theoretical results were in good agreement with those of FEM. It indicates that the present calculation model is easy and feasible, and the equivalent substitution of load almost has no influence on the final deflection. 展开更多
关键词 dynamic plastic response stiffened plates large deflection singly symmetric cross section
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Proton-induced Conversion from Non-Aufbau to Aufbau Electronic Structure of an Organic Radical with Turn-on Fluorescence
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作者 CHEN Zhangwu LI Feng 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2022年第3期798-802,共5页
We report a donor-acceptor(D-A)type non-luminescent neutral radical,tris-2,4,6-trichlorophenylmethyl-N,N-dimethyl-9H-carbazol-3-amine(TTM-Cz-DMA).The results of cyclic voltammetry and quantum chemistry calculation con... We report a donor-acceptor(D-A)type non-luminescent neutral radical,tris-2,4,6-trichlorophenylmethyl-N,N-dimethyl-9H-carbazol-3-amine(TTM-Cz-DMA).The results of cyclic voltammetry and quantum chemistry calculation confirm TTM-Cz-DMA has the non-Aufbau electronic structure,which means the singly occupied molecular orbital(SOMO)lies below the highest doubly occupied molecular orbital(HOMO).The non-Aufbau electronic structure changes to the Aufbau electronic structure after protonation and exhibits proton-responsive turn-on fluorescence,which is totally reversible by deprotonation.The dihedral angle between donor and acceptor moieties of TTM-Cz-DMA in excited state reduces from 88°to 62°after protonation,causing the turn-on fluorescence.Our results offer a viewing angle to understand the luminescence of radicals and provide a possible application of proton detection. 展开更多
关键词 Luminescent radical singly occupied molecular orbital(SOMO)-highest doubly occupied molecular orbital(HOMO)conversion Non-Aufbau Turn-on fluorescence
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On f-bi-harmonic maps and bi-f-harmonic maps between Riemannian manifolds
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作者 LU WeiJun 《Science China Mathematics》 SCIE CSCD 2015年第7期1483-1498,共16页
Both bi-harmonic maps and f-harmonic maps have some nice physical motivation and applications.Motivated largely by f-tension field not involving Riemannian curvature tensor, we attempt to formalize some large objects ... Both bi-harmonic maps and f-harmonic maps have some nice physical motivation and applications.Motivated largely by f-tension field not involving Riemannian curvature tensor, we attempt to formalize some large objects so as to broaden the notions of f-tension field and bi-tension field. We introduce a very large generalization of harmonic maps called f-bi-harmonic maps as the critical points of f-bi-energy functional, and then derive the Euler-Lagrange equation of f-bi-energy functional given by the vanishing of f-bi-tension field.Subsequently, we study some properties of f-bi-harmonic maps between the same dimensional manifolds and give a non-trivial example. Furthermore, we also study the basic properties of f-bi-harmonic maps on a warped product manifold so that we could find some interesting and complicated examples. 展开更多
关键词 bi-f-tension field f-bi-tension field bi-f-harmonic map f-bi-harmonic map singly warped prod-uct manifold
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The atomic structure and the properties of Ununbium (Z=112) and Mercury (Z=80)
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作者 S.FRITZSCHE B.FRICKE 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2007年第6期707-715,共9页
A super heavy element Uub (z = 112) has been studied theoretically in conjunction with rela-tivistic effects and the effects of electron correlations.The atomic structure and the oscillator strengths of low-lying leve... A super heavy element Uub (z = 112) has been studied theoretically in conjunction with rela-tivistic effects and the effects of electron correlations.The atomic structure and the oscillator strengths of low-lying levels have been calculated,and the ground states have also been determined for the singly and doubly charged ions. The influence of relativity and correlation effects to the atomic properties of such a super heavy element has been investigated in detail. The results have been compared with the properties of an element Hg. Two energy levels at wave numbers 64470 and 94392 are suggested to be of good candidates for experimental observations. 展开更多
关键词 super heavy element atomic structure relativistic effects electron correlation effects MCDF method
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一个有效的多边形裁剪算法 被引量:74
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作者 刘勇奎 高云 黄有群 《软件学报》 EI CSCD 北大核心 2003年第4期845-856,共12页
多边形裁剪与线剪裁相比具有更广泛的实用意义,因此它是目前裁剪研究的主要课题.提出了一个多边形裁剪多边形的有效算法.其中的多边形都可以是一般多边形,既可以是凹多边形,也可以是有内孔的多边形.该算法不仅可以求多边形的交(多边形裁... 多边形裁剪与线剪裁相比具有更广泛的实用意义,因此它是目前裁剪研究的主要课题.提出了一个多边形裁剪多边形的有效算法.其中的多边形都可以是一般多边形,既可以是凹多边形,也可以是有内孔的多边形.该算法不仅可以求多边形的交(多边形裁剪),而且可以求多边形的并和差.它是以所提出的一系列新方法和新技术为基础而形成的.首先,该算法使用单线性链表数据结构,与其他使用双链表或树结构的算法相比,具有 占用空间少及处理速度快的特点;其次,找到了两个多边形之间进、出点之间的关系.再通过合理的数据结构处理,减少了算法对多边形链表的遍历次数,而且允许多边形既可以按顺时针方向也可以按逆时针方向输入.最后,判断和计算交点是裁剪算法的主要工作.提出了一个具有最少计算量的交点判断和计算方法,进一步加快了算法的运行速度.与其他同类算法进行了比较,结果表明,新算法具有最简单的结构和最快的执行速度. 展开更多
关键词 多边形裁剪算法 计算机图形学 凹多边形 数据结构 图形处理
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刑事审判书面印证的负效应 被引量:19
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作者 林劲松 《浙江大学学报(人文社会科学版)》 CSSCI 北大核心 2009年第6期81-90,共10页
在我国当前案卷审判方式下,刑事印证呈现出明显的书面印证特征。印证方法在实现事实查证功能的同时,也潜藏着错误累加的风险。书面印证违背了先单个证据独立审查,后全案证据相互印证的印证规律,错误累加效应因而难以避免。书面印证还会... 在我国当前案卷审判方式下,刑事印证呈现出明显的书面印证特征。印证方法在实现事实查证功能的同时,也潜藏着错误累加的风险。书面印证违背了先单个证据独立审查,后全案证据相互印证的印证规律,错误累加效应因而难以避免。书面印证还会产生刺激、鼓励侦查机关制造"表面印证"的虚假案卷笔录的反向鼓励效应。在书面印证短期内难以抛弃的现状下,树立法官的单证审查意识,提高法官的单证审查能力,确立疑义出庭作证制度、庭上证言优先原则和审前证据展示制度,可以在一定程度上避免负效应的发生。 展开更多
关键词 案卷审判 书面印证 错误累加效应 反向鼓励效应 单证审查
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超短啁啾脉冲光束空间奇异性的形成与消除 被引量:17
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作者 杨振军 胡巍 +2 位作者 傅喜泉 陆大全 郑一周 《物理学报》 SCIE EI CAS CSCD 北大核心 2003年第8期1920-1924,共5页
研究了超短啁啾脉冲光束在真空中的传输行为以及在传输过程中时空奇异性的形成 .结果表明 ,对于脉冲时间较长 (相对于一个光学周期 )的超短啁啾脉冲光束 ,啁啾导致的脉冲光谱展宽仍然会导致脉冲光束空间奇异性的出现 .脉冲啁啾比脉冲长... 研究了超短啁啾脉冲光束在真空中的传输行为以及在传输过程中时空奇异性的形成 .结果表明 ,对于脉冲时间较长 (相对于一个光学周期 )的超短啁啾脉冲光束 ,啁啾导致的脉冲光谱展宽仍然会导致脉冲光束空间奇异性的出现 .脉冲啁啾比脉冲长度对脉冲光束空间奇异性的出现影响更大 .给出了超短啁啾高斯脉冲光束在不同参数下的数值模拟、空间奇异性出现的条件等 ,并用复解析信号理论消除了空间奇异性的出现 . 展开更多
关键词 超短啁啾脉冲光束 空间奇异性 数值模拟 复解析信号理论 形成 消除 传输过程 激光技术
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纳米ZnO颗粒在阳极Al_2O_3模板中的强光致发光研究 被引量:8
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作者 石刚 牟季美 +1 位作者 蔡维理 张立德 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2001年第1期95-99,共5页
用金属醇盐水解法在阳极Al2 O3模板的有序孔洞中生长了纳米量级的ZnO颗粒 ,并用扫描电子显微镜 (SEM )和高分辨电子显微镜 (HRTEM )对其形貌进行观察。对纳米ZnO/多孔阳极Al2 O3模板组装体的光致发光谱进行测量 ,将组装体中纳米ZnO颗粒... 用金属醇盐水解法在阳极Al2 O3模板的有序孔洞中生长了纳米量级的ZnO颗粒 ,并用扫描电子显微镜 (SEM )和高分辨电子显微镜 (HRTEM )对其形貌进行观察。对纳米ZnO/多孔阳极Al2 O3模板组装体的光致发光谱进行测量 ,将组装体中纳米ZnO颗粒的发光强度与常规方法制备的纳米ZnO颗粒发光强度做了比较 ,就发光强度提高的原因进行了讨论。 展开更多
关键词 纳米颗粒 光致发光 单离子氧空位 金属醇盐 水解法 制备 氧化锌 荧光材料 阳极三氧化铝模板
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院外坚持母乳喂养行为多因素分析 被引量:10
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作者 彭刚艺 《中国妇幼保健》 CAS 1995年第5期275-277,共3页
我们在广州市2所爱婴医院追踪调查221例4个月婴儿的母乳喂养情况,结暴发现:产妇出院后母乳喂养率呈逐月下降趋势。本文在单因素分析的基础上,采用多元回归分析的方法,筛选出影响母乳喂养持续行为的5个因素,根据标准偏回归系数绝对值大小... 我们在广州市2所爱婴医院追踪调查221例4个月婴儿的母乳喂养情况,结暴发现:产妇出院后母乳喂养率呈逐月下降趋势。本文在单因素分析的基础上,采用多元回归分析的方法,筛选出影响母乳喂养持续行为的5个因素,根据标准偏回归系数绝对值大小,各影响因素强度依次为:母乳量,母乳喂养咨询门诊,母亲患病,家庭经济收入及对“母乳喂养完全能满足4个月婴儿全部营养而不必给婴儿添加任何辅食”的看法。 展开更多
关键词 爱婴医院 母乳喂养 多变量分析
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衡阳方言的语气词 被引量:7
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作者 彭兰玉 《方言》 CSSCI 北大核心 2003年第2期171-176,共6页
衡阳方言的语气词比较丰富,大多数是单用的,也有一些可以连用。本文按衡阳方言的音序先描写单用的语气词,最后描写连用的语气词。
关键词 衡阳方言 语气词 音序 单用 连用
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