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DIELECTRIC REsPONsE AND IMPEDANCE sPECTROsCOPY OF(Na_(0.5)bi_(0.5))_(0.95)ba0:05Zr_(0.04)Ti_(0.96)O_(3)FERROELECTRIC CERAMIC

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Journal of Advanced Dielectrics 2012年第3期2卷 87-98页

作者： b.TILAK Department of Materials science Addis Ababa University Addis Ababa Ethiopia

A new lead-free ferroelectric relaxor ceramic was prepared by conventional solid-state synthesis by modifying A-site and b.s.te in(Na_(0.5)bi_(0.5))TiO_(3)system,i.e.,(Na_(0.5)bi_(0.5))_(0.95)ba_(0.05)Zr_(0.04)Ti_(0.96)O_(3)(0.05bNbZT).X-ray diiffraction studies reveal a single phase rhombohedral *** size and strain analysis has been done by Debye-scherrer and Williamson-Hall *** tolerance factor is 0.81,indicating a stable Perovskite structure of the *** electron micrograph of the material shows a distribution of grains,average grain size is 1.41μ*** response of(Na_(0.5)bi_(0.5))_(0.95)ba_(0.05)Zr_(0.04)Ti_(0.96)O_(3),ferroelectric ceramic has been studied as a function of frequency over a wide range of *** studied ceramic exhibited maximum frequency dispersion in both real and imaginary part of dielectric susceptibility at and around the dielectric transition temperature(T_(m)).The frequency dependence of transition temperature,T_(m)(temperature of the maximum of dielectric constant)was studied in terms of Vogel-Fulcher *** dielectric relaxation of(Na_(0.5)bi_(0.5))_(0.95)ba_(0.05)Zr_(0.04)Ti_(0.96)O_(3)ceramic was studied at different temperatures using the complex impedance(Z*)and electrical modulus(M*)*** measurements were made on over a wide range of temperatures(300-600℃)and frequencies(45 Hz-5 MHz)which show the presence of both grain and grain boundary effects in the *** Impedance spectroscopy is shown to be an effcient method capable of detecting the contributions of the resistances of grain boundaries(at higher temperature),in addition to granular contribution(at all temperatures),which influences the device properties of a *** electric modulus(M*)formalism used in the analysis enabled us to distinguish and separate the relaxation *** studies in the material obey the Jonscher's power law in frequency(45 Hz-5 MHz)and temperature(30

关键词： Lead-free ferroelectric ceramics relaxor VogelFulcher relationship impedance conductivity

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地震波形非线性反演的替代方法

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世界地震译丛 1994年第1期25卷 15-22页

作者： M. s. sambridge A. Tarantola b. L. N. Kennett 刘瑞文国家地震局地球物理勘探大队

大型非线性反演问题的一个普通例子是地震波形反演,通常解这类问题的方法涉及到求出观测与理论预测值之间某一失配函数的极小值。随着问题规模的增大,需要反演大矩阵的一些方法变得很麻烦,要执行反演并避免稳定性方面的问题就需要相当... 详细信息

大型非线性反演问题的一个普通例子是地震波形反演,通常解这类问题的方法涉及到求出观测与理论预测值之间某一失配函数的极小值。随着问题规模的增大,需要反演大矩阵的一些方法变得很麻烦,要执行反演并避免稳定性方面的问题就需要相当大的储存量和计算工作。因此,不需要任何大型矩阵反演的方法是很受欢迎的。目前,下降型算法正被广泛使用着。通常,在每次迭代时,由失配函数的梯度得出下降方向,并且根据这个方向或者还有以前的下降方向,对现有模型进行修正。几乎所有与地球物理有关的问题的共同特性是,反演中存在可分开的不同类型参数,即不同尺度和特征的未知数。然而,类型参数的这种基本差别在现用的反演算法中并没有反映出来。通常,梯度法或者将参数类型混在一起,因而不大注意个体特征,或者对它们在反演过程中的相对重要性假设了某种先验条件。我们提出了用于多重偏移反射资料的非线性反演的一种新方法。本文是纯理论性的,其目的在于示出已被用于反射波层析成象及三维构造到时反演的方法如何可用在波形反演中。我们特别示出了如何将Tarantola提出的方法扩展以便包含子空间结构。所提出的方法没有涉及到大规模矩阵的反演,但对反演中的不同参数类型给予了特别的注意。我们使用Tarantola的公式将问题表示成最优化问题,并得出了相同的下降矢量。新方法将下降矢量进行分离,使每一部分都取决于不同的类型参数,并在这些单个下降矢量定义的子空间中使失配函数最小。这样就最佳利用了下降矢量的分量,即依据问题在子空间内局部线性化能求出使失配函数产生最大减少的组合。其他梯度法不是这种情况。通过在选择的子空间内解被线性化了的问题,每次迭代时,只需要求一个小的良态矩阵的逆(将整个海赛算子投影到子空间上)。这种方法是梯度法和矩阵反演方法的一种混合方法,所提出的方法与Tarantola的方法一样,要求确定相同的梯度矢量,尽管其主要目的是更好地利用目标函数最小化过程中的那些计算结果。

关键词：地震波波形非线性反演替代法

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Dynamic microstructure evolution and mechanical properties of dilute Mg-Al-Ca-Mn alloy during hot rolling

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Journal of Materials science & Technology 2022年第34期129卷 1-14页

作者： shiwei Xu Congcong Zhu Zhanhong Lin Chen Jin s.Kamado K.Oh-ishi Yun Qin College of Materials science and Engineering Hunan UniversityChangsha 410082China state Key Laboratory of Advanced Design and Manufacturing for Vehicle body Hunan UniversityChangsha 410082China Qinghai salt Lake Teli Magnesium Co.Ltd. Xining 810000China Department of Mechanical Engineering Nagaoka University of TechnologyNagaoka 940-2188Japan Toyota Central R&D Labs. Inc.41-1 YokomichiNagakuteAichi 480-1192Japan Research Institute(R&D Centre) Baowu Steel Group CorporationShanghai 201900China

The dynamic microstructure and texture of dilute Mg-0.50Al-0.71Ca-0.33Mn(wt.%) during hot rolling at two slab temperatures were investigated by electron backscattered diffraction(EbsD) and high resolution transmission electron microscopy(HRTEM). The results show that the development of the rolling microstructures is to first form {10–12} extension twins in the original grains, thereby forming the extension-twinned regions, and then to further form {10–11}-{10–12} double twins and kinks in the extension-twinned regions, and finally to form continuous dynamic recrystallized(continuous DRXed)grains in the double twins and the cross parts of the shear-deformed coarse extension-twinned *** extension twins, double twins and kinks show a decisive effect on the formation of rolling *** number of {10–11}-{10–12} double twins and resultant the continuous DRX process are strongly affected by the rolling slab temperature and the reduction thickness per pass. by optimizing the rolling conditions, texture and microstructures of the multi-pass rolled Mg-Al-Ca-Mn alloy sheets are successfully modified. Although the total alloy content is only 1.5 wt.%, these Mg-Al-Ca-Mn alloy sheets show much higher strength than the commercial Mg-3Al-1 Zn(wt.%)(AZ31b) sheet.

关键词： Mg-Al-Ca-Mn alloy Hot rolling Dynamic recrystallization Texture control Mechanical properties

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High Density Plasma Heating by EC-Waves Injected from the High-Field side for Mode Conversion to Electron bernstein Waves in LHD

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Plasma science and Technology 2013年第2期15卷 93-96页

作者： Y.YOsHIMURA s.KUbO T.sHIMOZUMA H.IGAMI H.TAKAHAsHI M.NIsHIURA s.OGAsAWARA R.MAKINO T.MUTOH H.YAMADA A.KOMORI National Institute for Fusion science 322-6 Oroshi-cho Toki 509-5292 Japan Dept. of Energy science and Technology Nagoya Univ.Nagoya 464-8463 Japan

To realize an excitation of electron bernstein waves （EbW） via mode conversion from X-mode waves injected from the high magnetic field side （HFs）, new inner-vessel mirrors were installed close to a helicM coil in the large helicM device （LHD）. 77 GHz electron cyclotron （EC） wave beams injected from an existing EC-wave injection system toward the new mirror are reflected on the mirror so that the beams are injected to plasmas from HFs. Evident increases in the electron temperature at the plasma core region and the plasma stored energy were observed by the HFs beam injection to the plasmas with the line-average electron density of 7.5~ 1019 m-3, which is slightly higher than the plasma cut-off density of 77 GHz EC-waves, 7.35~ 1019 m-3. The heating efficiency evaluated from the changes in the time derivative of the plasma stored energy reached ,,~70%. Although so far it is not clear which is the main cause of the heating effect, the mode-converted EbW or the X-mode wave itself injected from the HFs, an effective heating of high-density plasma over the plasma cut-off of EC-wave was successfully demonstrated.

关键词： electron bernstein wave EbW slow X-b overdense high density plasmaheating high-field side injection ECH LHD

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synthesis and characterization of lithium niobium borate glasses containing neodymium

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Journal of Rare Earths 2016年第12期34卷 1199-1205页

作者： W.H.A.Kamaruddin M.s.Rohani M.R.sahar LIU Hong sANG Yuanhua AOMRG Lab Physics Department Faculty of Science Universiti Teknologi Malaysia state Key Laboratory of Crystal Materials Shandong University

A series of（90–x）Li2b4O7-10Nb2O5-xNd2O3 glass samples（x=0, 5 mol.%, 10 mol.%, 15 mol.%, 20 mol.% and 25 mol.%） were synthesized using melt quenching technique. X-ray diffraction（XRD）, differential thermal analyzer（DTA）, Fourier transformed infrared（FTIR）, ultraviolet-visible-near-infrared（UV-Vis-NIR） spectrometer and photoluminescence（PL） spectroscopic characterizations were made to examine the influence of Nd3＋ concentration on the physical, structural and optical properties. Various physical properties such as glasses density, molar volume, thermal stability, ion concentration, polar on radius, inter-nuclear distance, field strength, cut-off wavelength, energy band gap and Urbach energy were calculated. The samples were amorphous in nature and confirmed from XRD pattern. The FTIR spectra revealed the presence of bO3 and bO4 functional groups. UV-Vis-NIR spectra exhibited nine prominent bands centered at 353, 430, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to ^4D（3/2）, ^2P（1/2）, ^2G（9/2）, ^4G（7/2）, ^4G（5/2）, ^4F（9/2）, ^4F（7/2）, ^4F（5/2）, ^4F（3/2） excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed three peaks centered at 903 nm（^4F（3/2）→^4I（9/2））, 1059 nm（^4F（3/2）→^4I（11/2）） and 1333 nm（^4F（3/2）→^4I（13/2））, respectively. Fluorescence lifetime was recorded between 53.69 to 28.43 μs. It was found that varying concentration of Nd^（3＋） ions strongly affected the physical, structural and optical properties of the glass samples.

关键词： borate glass neodymium optical properties band gap luminescence rare earths

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砷化镓注入式激光雷达

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红外与激光工程 1973年第4期 47-60页

作者： b.s.Goldstein G.F.Dalrymple

评价了在微弱的和强的背景辐射条件下砷化镓激光雷达对连续目标和角反射器的测距能力。对空间环境作了计算。制作了一部实验砷化镓激光雷达。展示了在大气中用这部雷达对几个漫反射目标和一个角反射器所获得的工作结果。

关键词：激光雷达光雷达角反射器伪装器材光电子散粒噪声散弹噪声暗电流背景辐射视场注入式光电倍增管球面度砷化镓砷化物

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Evolutionary Dynamics of Transposable Elements in soybean

Evolutionary Dynamics of Transposable Elements in Soybean

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第十二届全国植物基因组学大会

作者： Christian s.Hans Howard M.Laten steven b.Cannon scott A.Jackson Randy C.shoemaker Department of Agronomy Purdue UniversityWest Lafayette 47906USA Department of biology Loyola University ChicagoChicagoIl 60660USA

The availability of complete or nearly complete genome sequences from several plant species permits detailed discovery and cross-species comparison of transposable elements(TEs) at the whole genome level. We initially investigated 510 long terminal repeat-retrotransposon(LTR-RT) families comprising 32 370 elements in *** 87%of these elements were located in recombination suppressed pericentromeric *** analysis revealed a significant positive correlation between ratio of solo LTRs to intact elements and LTR sizes,indicating that larger LTRs facilitate solo LTR *** analysis

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无压力室喷油嘴液力研磨对直喷式柴油机混合气形成的影响

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汽车与新动力 1998年第4期 49-59页

作者： Kampmann s Dittus b Mattes P 何庆康

液力研磨(HG)工艺可应用于无压力室喷油嘴(VCO)产品上。当确定VCO喷油嘴液力研磨对增压型高速直喷式柴油机混合气形成的影响,进行了全面的理论计算与试验研究。搞清了液力研磨喷油嘴的喷束特性能满足增压型高速直喷式(HsDI)柴油机混合... 详细信息

液力研磨(HG)工艺可应用于无压力室喷油嘴(VCO)产品上。当确定VCO喷油嘴液力研磨对增压型高速直喷式柴油机混合气形成的影响,进行了全面的理论计算与试验研究。搞清了液力研磨喷油嘴的喷束特性能满足增压型高速直喷式(HsDI)柴油机混合气形成的要求。

关键词：直接喷射柴油机喷油嘴工艺燃烧过程研究

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First-principles study of structural,electronic,and optical properties of cubic InAs_xN_yP_(1-x-y) triangular quaternary alloys

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Chinese Physics b 2017年第1期26卷 425-432页

作者： I Hattabi A Abdiche F soyalp R Moussa R Riane K Hadji s bin-Omran R Khenata Laboratoire synthese et Catalyse Ibn Khaldoun Universite of Tiaret Tiaret 14000 Algeria Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M) Departement de Technologie Universite de Mascara Mascara 29000 Algeria Department of Physics Faculty of Education Yuzuncu Ytl University 65080 Van Turkey science and Technology D6partement Ibn Khaldoun Universite de Tiaret Tiaret 14000 Algeria Department of Physics and Astronomy College of Science King Sand University Riyadh 11451 Saudi Arabia

In this paper, we investigated the structural, electronic and optical properties of InAs, InN and InP binary compounds and their related ternary and quaternary alloys by using the full potential linearized augmented plane wave（FP-LAPW）method b.s.d on density functional theory（DFT）. The total energies, the lattice parameters, and the bulk modulus and its first pressure derivative were calculated using different exchange correlation approximations. The local density approach（LDA） and Tran–blaha modified becke–Johnson（Tb-m bJ） approximations were used to calculate the band *** variations of the lattice parameters, the bulk modulus and the band gap with compositions x and y are ***, the optical properties and the dielectric function, refractive index and loss energy were computed. Our results are in good agreement with the validated experimental and theoretical data found in the literature.

关键词： density functional theory full potential linearized augmented plane wave Tran–blaha modified becke–Johnson approximations InAsxNyP1-x-y

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Is There an Absolute scale for speed?

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Journal of Modern Physics 2022年第8期13卷 1184-1196页

作者： Ricardo b. Ferreira Joã o b. Ferreira Instituto superior de Agronomia University of Lisbon Lisbon Portugal Instituto Português de Oncologia de Lisboa Francisco Gentil Lisbon Portugal

Except for the speed of photons in vacuum, all speeds are relative. Could we develop an absolute scale for speed in which relative values for speed may be arbitrarily positioned and compared in absolute terms? The currently accepted definition for the meter as the distance covered by photons in vacuum during 1/299,792,458 s, and the view that the greater a material particle is accelerated towards c, the greater time dilation and length contraction will be, suggest that anything disturbing one of the four spacetime dimensions may affect the other three as well. One hypothetical experiment, one real experiment performed in the 1970s, and one experiment from a different field of science are discussed to propose that both time and velocity are only partially relative. In the first experiment, person A is standing still on the Earth’s surface, and person b is onboard a train passing by person A at the constant speed of 60 km/h (as measured by person b on the train’s speedometer). Persons A and b define two distinct inertial frames of reference, which correspond to two different spacetime conditions and which are therefore characterized by comparatively different lengths of the meter and durations of the second, as predicted by the Lorentz factor. Therefore, if person b onboard the train measures the train’s speed relative to person A as 60 km/h, a simple calculation will show that person A will perceive the train passing by at 59.99999999999981455834 km/h. If we consider the speed of photons in vacuum (c = 299,792,458 m/s) as a universal reference, and if we consider that the greater a material particle is accelerated towards c, the greater time dilation and length contraction will be, then person C, occupying an independent, distinct inertial frame of reference, will be unable to determine persons A and b.s.absolute speeds, but may infer which one is moving at a speed closer to c by comparing, with his own meter and second, the durations of the second and the lengths of

关键词： spacetime Relativity speed of Light space Time

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