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121.
采用四个不同偏振方向的线偏振和圆偏振态飞秒激光扫描处理金属铁表面来制备不同的彩色铁。从不同角度观察被处理区域时,线偏振扫描处理的彩色区域呈现不同的色彩,而圆偏振扫描处理的区域没有明显的颜色变化。扫描电子显微镜图片显示,线偏振激光扫描处理金属铁表面形成了nm量级的激光诱导周期表面结构,其方向始终与激光偏振方向垂直;圆偏振激光扫描处理金属铁表面形成的条纹结构不明显且有大量的纳米颗粒结构。  相似文献   
122.
The multidimensional phoneme identification model is applied to consonant confusion matrices obtained from 28 postlingually deafened cochlear implant users. This model predicts consonant matrices based on these subjects' ability to discriminate a set of postulated spectral, temporal, and amplitude speech cues as presented to them by their device. The model produced confusion matrices that matched many aspects of individual subjects' consonant matrices, including information transfer for the voicing, manner, and place features, despite individual differences in age at implantation, implant experience, device and stimulation strategy used, as well as overall consonant identification level. The model was able to match the general pattern of errors between consonants, but not the full complexity of all consonant errors made by each individual. The present study represents an important first step in developing a model that can be used to test specific hypotheses about the mechanisms cochlear implant users employ to understand speech.  相似文献   
123.
杨红龙  李磊  杨溯  卢超  陈星登  刘爱明 《光子学报》2014,41(12):1427-1434
气溶胶是影响气候变化和空气污染的重要因子.在深圳地区展开气溶胶观测实验,可以获得可靠的光学物理特征,进而有助于准确评估气溶胶在新型超极城市区域的气像和环境效应.本文利用2010年12月至2011年8月太阳光度计、黑碳和浊度计等气溶胶观测资料,分析了新型超级城市深圳地区的气溶胶物理光学特性.深圳地区气溶胶呈明显季节变化,冬、春季由于城市污染性气溶胶的影响,气溶胶光学厚度和Angstrom波长指数都较大,夏季受海盐气溶胶的影响,光学厚度较小,Angstrom波长指数也较小.光学厚度与Angstrom 波长指数对比表明城市综合性污染是引起深圳气溶胶高光学厚度的主要原因.深圳地区气溶胶的散射系数、吸收系数的平均值(标准偏差)分别为178.7×10-6 m-1(126.6×10-6 m-1)和32.5×10-6 m-1(18.1×10-6 m-1),均低于珠三角腹地多年观测平均值的二分之一和国内其他大型城市观测值.而单次散射反照率为0.81,与珠三角其他地区得到的结果接近.此外,气溶胶吸收、散射和单次散射反照率呈明显日变化,可能主要受大气边界层变化的影响.  相似文献   
124.
In this study, the effect of ultraviolet treatment on the band bending at the poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate)/indium tin oxide (PEDOT:PSS/ITO) interfaces were researched. The authors suggested that ultraviolet treatment could lead to a reduction in the band bending at the PEDOT:PSS/ITO interface, owing to the removal of carbon contamination at the ITO surfaces and a decrease in the number of the trap-states at the PEDOT:PSS/ITO interface.  相似文献   
125.
In this paper, the temperature dependence of magnetic properties and specific heat are systematically investigated for perovskite ErCrO3 chromites. The results show that there exists a strong temperature dependence of magnetic ordering and phase coexistence in the region of low temperature. Specifically, ErCrO3 possesses the long-range antiferromagnetic ordering and the appearance of weak ferromagnetism, occurring at T N =133 K. In the range of higher temperature, above 133.0 K, the reciprocal of magnetic susceptibility χ −1 behaves linearly, indicating a typical Curie–Weiss behavior fitted. The effective magnetic moment μ eff=10.57μ B and asymptotic paramagnetic Curie temperature T cw=−30 K, which suggests the predominance of antiferromagnetic interactions in ErCrO3 chromites. Around T SR≈22 K, ErCrO3 undergoes a spin reorientation from \varGamma 4(Gx,Ay,Fz;FRz)\varGamma _{4}(G_{x},A_{y},F_{z};F^{R}_{z}) to \varGamma 1(Ax,Gy,Cz;CRz)\varGamma _{1}(A_{x},G_{y},C_{z};C^{R}_{z}) or Γ 1(0). Also, the stability of the ferromagnetic Γ 4 phase increases with increasing applied field. Furthermore, the ac susceptibilities exhibit frequency-independent anomalies near 133 K and the coexistence of the magnetic configuration \varGamma 2(Fx,Gy,Cz;FRx,CRy)\varGamma _{2}(F_{x},G_{y},C_{z};F^{R}_{x},C^{R}_{y}) and Γ 4. Combining the magnetic properties and the specific-heat measurements, this current magnetization can be interpreted from the interaction between C r3+–Cr3+, Cr3+–Er3+ and Er3+–Er3+.  相似文献   
126.
A synchrotron‐radiation‐based circular‐dichroism end‐station has been implemented at beamline BL04B at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan for biological research. The design and performance of this compact end‐station for measuring circular‐dichroism spectra in the vacuum‐ultraviolet region are described. The linearly polarized light from the beamline is converted to modulated circularly polarized light with a LiF photoelastic modulator to provide a usable wavelength region of 130–330 nm. The light spot at the sample position is 5 mm × 5 mm at a slit width of 300 µm and provides a flux greater than 1 × 1011 photons s?1 (0.1% bandwidth)?1. A vacuum‐compatible cell made of two CaF2 windows has a variable path length from 1.3 µm to 1 mm and a temperature range of 253–363 K. Measured CD spectra of (1S)‐(+)‐10‐camphorsulfonic acid and proteins demonstrated the ability of this system to extend the wavelength down to 172 nm in aqueous solution and 153 nm in hexafluoro‐2‐propanol.  相似文献   
127.
超导技术在飞轮储能系统中的应用及前景   总被引:1,自引:0,他引:1  
阐述了飞轮储能装置原理和超导磁悬浮理论,并设计了超导飞轮储能系统的基本结构。采用超导磁悬浮轴承技术可以解决普通的飞轮储能系统由于有机械轴承摩擦产生的能量损耗,克服普通飞轮储能的低效、储能时间短等问题。最后简要介绍了超导飞轮储能技术的发展前景。  相似文献   
128.
Ultraviolet and visible upconversion emissions in Tb3+/Yb3+ co-doped YF3–BaF2–Ba(PO3)2 glasses were observed under 980-nm laser diode excitation. The dependence of the emission intensities of Tb3+ on the pump power reveals that two-photon processes account for blue cooperative emission of Yb3+ at 476 nm and green upconversion emission of Tb3+ at 543 nm, and three-photon processes for ultraviolet emission of Tb3+ in the wavelength range of 379–435 nm. The effects of Tb3+ concentration on the emission intensity and the lifetime of Tb3+ and Yb3+ are investigated in detail. It is found that the cooperative energy transfer from a pair of excited Yb3+ ions to a ground Tb3+ ion is responsible for the appearance of blue and green upconversion emissions due to the 5D47F J (J=6,5,4,3) transitions of Tb3+, and the resonance energy transfer from Yb3+ to Tb3+ accounts for the population on the 5D3,5G6 level and ultraviolet upconversion emission.  相似文献   
129.
The influence of the extra classical noises in seed beams on the entanglement between the signal and the idler modes of the output fields generated by a non-degenerate optical parametric amplifier operating at deamplification is investigated theoretically and experimentally.With the increase of the extra classical noises in the seed beams,the correlation degree of the output entangled optical fields,which is scaled by the quantum noise limit,decreases rapidly.The experimental results are in good agreement with the theoretical calculations.  相似文献   
130.
Polarization-dependent linear absorption, second-harmonic generation (SHG) and 3rd-order nonlinearities of wellaligned ZnO nanorod arrays have been investigated with ps pulses. The depressed spectral width and the enhanced intensity of reflective SHG along the long axis of ZnO nanorods were observed by using p-polarized pulses, which is explained by the optical confinements. The nonlinear absorption coefficient measured with s-polarization reached the maximum 4.0×10^4cm/GW at the wavelength -750nm, which revealed a large two-photon resonance absorption attributed to the quantum confined exciton when the polarization is vertical to the long axis of ZnO nanorod.  相似文献   
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