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81.
Spin gapless semiconductor like Ti2MnAl film as a new candidate for spintronics application 下载免费PDF全文
Wuwei Feng Xiao Fu Caihua Wan Zhonghui Yuan Xiufeng Han Nguyen Van Quang Sunglae Cho 《固体物理学:研究快报》2015,9(11):641-645
A novel Heusler ferrimagnet Ti2MnAl film has been grown on Si(001) substrate using magnetron sputtering. Characteristics of its magnetic and transport properties reveal the spin‐gapless‐semiconductor (SGS) nature of the stoichiometric Ti2MnAl, in agreement with theoretical prediction. The as‐grown SGS‐like Ti2MnAl film demonstrated high Curie temperature, nearly compensated ferrimagnetic properties with small coercivity and low magnetization. It also showed semiconductor‐like behavior at room temperature allowing good compatibility with commercial Si‐based semiconductor. In this regards, Ti2MnAl film is a potential candidate material for spintronics application, especially for the minimization of energy consumption of device. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
82.
Bright-field transmission electron microscopy (TEM) images, high-resolution TEM (HRTEM) images, and fast-Fourier transformed electron-diffraction patterns showed that n-butyl terminated Si nanoparticles were aggregated. The formation of Si1−xCx nanocomposites was mixed with Si nanoparticles and C atoms embedded in a SiO2 layer due to the diffusion of C atoms from n-butyl termination shells into aggregated Si nanoparticles. Atomic force microscopy (AFM) images showed that the Si1−xCx nanocomposites mixed with Si nanoparticles and C atoms existed in almost all regions of the SiO2 layer. The formation mechanism of Si nanoparticles and the transformation mechanism of n-butyl terminated Si nanoparticles embedded into Si1−xCx nanocomposites mixed with Si nanoparticles and C atoms are described on the basis of the TEM, HRTEM, and AFM results. These results can help to improve the understanding of the formation mechanism of Si nanoparticles. 相似文献
83.
84.
Seong Cho Dana Jones Wilburn E. Reddick Robert J. Ogg R.Grant Steen 《Magnetic resonance imaging》1997,15(10):1133-1143
The goal of this study was to determine the expected normal range of variation in spin-lattice relaxation time (T1) of brain tissue in vivo, as a function of age. A previously validated precise and accurate inversion recovery method was used to map T1 transversely, at the level of the basal ganglia, in a study population of 115 healthy subjects (ages 4 to 72; 57 male and 58 female). Least-squares regression analysis shows that T1 varied as a function of age in pulvinar nucleus (R2 = 56%), anterior thalamus (R2 = 51%), caudate (R2 = 50%), frontal white matter (R2 = 47%), optic radiation (R2 = 39%), putamen (R2 = 36%), genu (R2 = 22%), occipital white matter (R2 = 20%) (all p < 0.0001), and cortical gray matter (R2 = 53%) (p < 0.001). There were no significant differences in T1 between men and women. T1 declines throughout adolescence and early adulthood, to achieve a minimum value in the fourth to sixth decade of life, then T1 begins to increase. Quantitative magnetic resonance imaging provides evidence that brain tissue continues to change throughout the lifespan among healthy subjects with no neurologic deficits. Age-related changes follow a strikingly different schedule in different brain tissues; white matter tracts tend to reach a minimum T1 value, and to increase again, sooner than do gray matter tracts. Such normative data may prove useful for the early detection of brain pathology in patients. 相似文献
85.
S.-H. Cho H. Kumagai K. Midorikawa 《Applied Physics A: Materials Science & Processing》2003,76(5):755-761
The time-resolved dynamics of plasma self-channeling and refractive index bulk modification in silica glasses were first observed
in situ using a high-intensity femtosecond (110 fs) Ti:sapphire laser (λp=790 nm). Plasma channeling is induced in silica glass at an irradiation higher than an input intensity of 1.5×1012 W/cm2 and photoinduces either the refractive-index modification or optical crack modification. In the domain of refractive-index
modification, the lifetime of induced plasma self-channeling was 20 ps and the structural transition time for forming the
refractive-index change was 10 ps. In the domain of optical cracks, however, the lifetime of induced plasma formation was
30 ps and the structural transition time for forming the optical cracks was 40 ps. According to electron spin resonance spectroscopic
(ESP) measurement, it was found that the defect concentration of the SiE′ center increased significantly in the refractive index modification region. A maximum value of the refractive-index change
Δn was measured to be 1.6×10-2. The intensity profile of the output beam transmitted through the refractive-index modification showed that the bulk modification
produced a permanent optical waveguide.
Received: 8 April 2002 / Accepted: 12 April 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +81-48/462-4682, E-mail: shcho@riken.go.jp 相似文献
86.
简单介绍了近年来在超重核研究方面所取得的成就和理论方面所面临的挑战.着重介绍推广的液滴模型和准分子形状机制,它们的优点是考虑了精确的核半经、质量和电荷的不对称性、形变、亲和力和温度等.推广的液滴模型和准分子形状机制能很好地描述重核和超重核的裂变、衰变及完全熔合反应.The progress and challenge on studies of superheavy elements both experiments and theories has been briefly introduced. It is emphasis to introduce a generalized liquid drop model, including the proximity effects, the asymmetry, an accurate nuclear radius, and quasi molecular shapes. The α decay half lives of 373 nuclei and superheavy elements have been calculated in the generalized liquid drop model and compared with the available experimental data. The deformed energies have also been obtained ... 相似文献
87.
Fluorine substituted Li1.27Cr0.2Mn0.53O2 electrode, prepared by sol–gel method, was investigated in the present work. Thermal analysis was done on this cathode material
and found to be thermally stable with a loss of weight near 300 °C. Influence of fluorine substitution on the structural and
electrochemical properties of the Li1.27Cr0.2Mn0.53O2 electrode was studied by X-ray diffraction (XRD) and field emission scanning electron microscope. XRD pattern of the fluorine-doped
Li1.27Cr0.2Mn0.53O2 cathode material quenched at 900 °C indicates a phase pure material. The charge–discharge profile of the prepared cathode
material showed that the fluorine substitution for oxygen in the cathode material resulted in improved capacity retention.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, December 7–9,
2006. 相似文献
88.
S.I. Jung J.J. Yoon H.J. Park Y.M. Park M.H. Jeon J.Y. Leem C.M. Lee E.T. Cho J.I. Lee J.S. Kim J.S. Son J.S. Kim D.Y. Lee I.K. Han 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):100
We investigate the effects of a thin AlAs layer with different position and thickness on the optical properties of InAs quantum dots (QDs) by using transmission electron microscopy and photoluminescence (PL). The energy level shift of InAs QD samples is observed by introducing the thin AlAs layer without any significant loss of the QD qualities. The emission peak from InAs QDs directly grown on the 4 monolayer (ML) AlAs layer is blueshifted from that of reference sample by 219 meV with a little increase in FWHM from 42–47 meV for ground state. In contrast, InAs QDs grown under the 4 ML AlAs layer have PL peak a little redshifted to lower energy by 17 meV. This result is related to the interdiffusion of Al atom at the InAs QDs caused by the annealing effect during growing of InAs QDs on AlAs layer. 相似文献
89.
Quality-guided algorithm is a widely used method in phase unwrapping. This paper shows an accurate quality map based on fringe contrast for 3D shape measurement. Phase-shifted fringe patterns are projected onto an object surface by a programmable liquid crystal projector and recorded by a CCD camera. A wrapped phase map and a fringe contrast map are extracted from the deformed fringe patterns by the phase-shifting technique. Guided by the contrast map, the quality-guided unwrapping algorithm minimizes unwanted shadow and non-uniform surface reflectance effects and is able to retrieve a correct surface profile. Validity of the proposed method is tested on a fish model and a cutting tool specimen. 相似文献
90.