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排序方式: 共有1049条查询结果,搜索用时 93 毫秒
941.
An optical fiber diameter monitor, Type GY-A, was developed especially for fiber drawing. A new method, the pulling force-temperature method, is presented. The fiber drawing stability is improved and the fluctuation of the fiber diameter is 0.3 μm (rms). 相似文献
942.
943.
The linestrengths, self-pressure broadening and shifting coefficients have been measured for P3 (10)- R3 (12) lines in the second overtone band of hydrogen iodide. A dipole moment function in terms of the reduced nuclear displacement x = (R − Re)/Re is obtained using rotationless dipole matrix elements determined by the Herman-Wallis analysis of the (1, 2, 3 ← 0) HI bands: μ (x) = 0.4471(5) − 0.0770(2)x + 0.547(3)x2 − 1.93(2)x3, in a full agreement with the function proposed previously [J. Mol. Spectrosc. 223 (2004) 67]. A close match is demonstrated of the results of most recent relativistic calculations [Phys. Chem. Chem. Phys. 6 (2004) 3779] with the spectroscopically derived electric dipole parameters for HI. Line-mixing in the band head is observed, the self-pressure shifting and broadening coefficients for the (3 ← 0) band lines are determined. 相似文献
944.
Edward Arvalo 《Physics letters. A》2009,373(39):3541-3546
The effect of instability on the propagation of solitary waves along one-dimensional discrete nonlinear Schrödinger equation with cubic nonlinearity is revisited. A self-contained quasicontinuum approximation is developed to derive closed-form expressions for small-amplitude solitary waves. The notion that the existence of nonlinear solitary waves in discrete systems is a signature of the modulation instability is used. With the help of this notion we conjecture that instability effects on moving solitons can be qualitative estimated from the analytical solutions. Results from numerical simulations are presented to support this conjecture. 相似文献
945.
An analytical expression for a single-pulse nuclear echo signal in magnetically ordered materials has been obtained taking
into account inhomogeneous broadening of the spectroscopic transition and non-uniform distribution of the enhancement factor.
The signal has been shown to result from superimposing the nuclear magnetic moment oscillations of the same amplitude and
phase that arise upon termination of a radio-frequency pulse. The cause for the effective suppression of oscillations of nuclear
magnetic moments in the initial phase of the free precession signal has been determined analytically. The single-pulse echo
signal amplitude has been found as a function of the external variable magnetic field strength, the exciting pulse duration,
the inhomogeneous NMR line broadening, and the distribution width of the enhancement factor. The results have been compared
with experimental data observed in a Co2MnSi ferromagnetic polycrystalline sample.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 387–394, May–June, 2009. 相似文献
946.
Ken-Ichi Kitayama 《Fiber and Integrated Optics》2000,19(2):167-186
The architecture of fiber-radio mm-wave wireless access systems critically depends upon the optical mm-wave generation and transport techniques. Four optical mm-wave generation and transport techniques: 1) optical self-heterodyning, 2) external modulation, 3) up- and downconversion, and 4) optical transceiver, will be assessed. From the technical viewpoints, their advantages and disadvantages are discussed. The economical assessment, focusing on the cost of a base station BS ( ), will suggest that the optical transceiver looks the most promising in the long run, but in the near future, however, the external modulation will be cost-effective. The experimental results of 60 GHz testbeds using the external modulation will support the conclusion. 相似文献
947.
The modulation transfer function (MTF) of a pixelated liquid crystal spatial light modulator (LC-SLM) has been derived as a function of the fill factor. Based on the formula, we have investigated the dependence of the MTF on the orientations and spatial frequency of the input patterns. Furthermore, we have proposed and demonstrated a method for improving the MTF of a LC-SLM. 相似文献
948.
Catherine García Reimbert Antonmaria A. Minzoni T.R. Marchant Noel F. Smyth Annette L. Worthy 《Physica D: Nonlinear Phenomena》2008,237(8):1088-1102
The interaction of two symmetric solitary waves, termed nematicons, in a liquid crystal is considered in the limit of nonlocal response of the liquid crystal. This nonlocal limit is the applicable limit for most experimentally available liquid crystals. In this nonlocal limit, two separate cases for the initial separation of the nematicons are considered, these being large and small separation. Both spinning and nonspinning nematicons are considered. It is found that in the case of large initial separation, the nematicons can form a spinning or nonspinning bound state with a finite steady separation, this being called a nematicon dipole, when they are π out of phase. On the other hand, well separated, nonspinning, in-phase nematicons attract and merge, while well separated, spinning, in-phase nematicons can either form a bound state or merge into a single nematicon. In the limit of small initial separation, the nematicons rapidly merge when they are in phase. Modulation equations describing the nematicon interaction are derived via suitable trial functions in an averaged Lagrangian. These modulation equations are further modified to include the effect of the diffractive radiation shed as the nematicons evolve. Finally the modulation equations are approximated in order to investigate the various interaction regimes. Good to excellent agreement is found between their solutions and full numerical solutions of the nematicon equations. 相似文献
949.
高速光纤通信系统中高阶PMD的优化建模 总被引:1,自引:0,他引:1
为了评估随机变化的偏振模色散(PMD)(包括一阶和二阶PMD)使系统信号裂化的程度,降低其对高速光纤通信系统传输速率和传输容量的不利影响,在斯托克斯空间中推导了偏振模色散(PMD)矢量的数学表达式。对PMD效应所导致的脉冲展宽进行了数学分析,给出了差分群时延(DGD)的变化、一阶PMD矢量和二阶PMD矢量方向的变化对脉冲展宽的影响。通过数学推导得出,在大多数情况下,二阶PMD无法完全补偿,需通过控制单元的调整使其对系统的影响达到极小值。通过实验分析,得到了和数学推导中同样的结果,从而证明了模型的正确性。 相似文献
950.