进口附面层厚度对大转角弯叶片损失的影响

进口附面层厚度对大转角弯叶片损失的影响韩万今，吕红卫，芦文才，王仲奇（哈尔滨工业大学哈尔滨１５０００１）关键词：进口附面层，大转角，弯叶片叶片损失来源于两方面：一是进口附面层带来的“原”损失，二是绕流叶栅产生的新损失。二次流引起“原”损失重新分布，并...     

利用象增强器构成光电相关鉴相器面阵的研究

本文介绍了利用阴极可控的微通道板象增强器构成面阵型光电相关鉴相器的原理,采用了方波与正弦波相关的方案,在微通道板象增强器的光电阴极加上方波门控电压,把它作为参考信号,测量具有相位差的同频正弦波光信号,研究了它的一些基本特性,给出了这种面型鉴相器的潜在应用.     

强光场中原子的电离速率

以静态场隧道电离为基础,在准静态近似的条件下,对描述强光场中原子及其各阶离子电离的电离速率进行了较为系统的总结,纠正了早期对隧道电离的电离速率公式进行讨论并且后来的计算中被广泛引用的文献「１０」中公式的错误,地部分稀有气体原子及其各了子在线偏振、圆偏振强光场中的了速度及相应的阈值光强进行了比较。     

Ⅳ-Ⅵ族半导体材料磁场下的红外介电函数

给出了经典极限下多能谷Ⅳ-Ⅵ族化合物半导体在磁场下的红外介电函数的一般解析表达式,并通过与k·P模型的结合给出了红外介电函数的半经典处理途径。通过对典型Ⅳ-Ⅵ族化合物半导体材料PbTe红外介电函数的计算,讨论了能带非抛物性和载流子浓度在多能谷体系中的分布效应对红外介电函数的影响。 关键词：     

Si1-xCex/Si量子阱发光材料制备及特性研究

在si(100)衬底上用分子束外延成功生长了Si_(1-x)Ge_x/si量子阱发光材料,发现在生长过程中背景杂质含量直接影响材料的发光特性,用光致发光(PL)和卢瑟福背散射(RBS)对样品质量进行标定。在PL测量中观察到合金量子阱带边激子分辨峰,并对发光峰能和峰宽作了讨论。 关键词：     

Optical properties and highly efficient laser oscillation of Nd:YAG ceramics

Optical absorption, emission spectra have been measured for polycrystalline Nd-doped Y₃Al₅O₁₂ ceramics. Fluorescence lifetimes of 257.6 μs, 237.6 μs, 184.2 μs and 95.6 μs have been obtained for 0.6%, 1%, 2% and 4% neodymium-doped YAG ceramics, respectively. For the first time, highly efficient laser oscillation at 1064 nm has been obtained with this kind of ceramics. Slope efficiency of 53% has been achieved on a uncoated 4.8-mm thick 1% Nd:YAG ceramics sample. Optical to optical conversion efficiency is 47.6%. Laser oscillation has also been obtained with a 2% Nd:YAG ceramics. The optical properties and laser output results have been compared with that of Nd:YAG single crystal grown by the Czochralski method. Almost identical results have been achieved including laser experiments results. But fabrication of Nd:YAG ceramics is much easier compared to the single-crystal growth method. And also large size (now of about 400 mm diameter×5 mm is available) and high-concentration (>1%) Nd:YAG ceramics can be fabricated. The results show that this kind of Nd:YAG ceramics is a very good alternative to Nd:YAG single crystal. Received: 20 April 2000 / Published online: 16 August 2000     

[Mo3S7]分子簇和聚合簇合物的振动光谱和电子光谱

本文报道了分立簇「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」１及它的四聚物｛「Ｍｏ３ＳＵ（ｄｔｐ）３」４Ｉ｝．｛（ＨｇＩ３）４．Ｋ｝２（ｄｔｐ＝Ｓ２Ｐ（ＯＣ２Ｈ５）＾－２的ＩＲ,Ｒａｍａｎ和ＵＶ－Ｖｉｓ光谱,并讨论分立的「Ｍｏ３Ｓ７（ｄｔｐ）３Ｉ」在四聚后这些光谱的变化。     

一类广义幂零群

This paper considers such a group G which possesses nontrivial proper subgroups H 1 ,H 2 such that any proper subgroup of G not contained in H 1 ∪ H 2 is p-closed and obtains that if G is soluble,then the number of prime divisors contained in ｜G｜ is 2,3 or 4;if not,then it has a form x N where N/Φ（N） is a non-abelian simple group.Then the structure of such a group is determined for p = 2,H 1 = H 2 under some conditions.     

Generalization of Einstein relation for doped organic semiconductors

Under the assumption of Gaussian energy distributions of the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO), analytical expressions of generalized Einstein relation for electron and hole transport in doped organic semiconductor thin films are developed. Numerical calculations show that, although traditional Einstein relation still holds for low carrier concentrations, that is, the diffusion-coefficient-to-mobility ratio in units of k_BT/q, with k_B the Boltzmann’s constant, T the temperature and q the elementary charge, equals 1. But when the electron (hole) concentration is high, the diffusion-coefficient-to-mobility ratio for electrons (holes) changes strongly with the electron (hole) concentration, the doping level, the mean energy of LUMOs (HOMOs) of the dopant E_Ld (E_Hd) and the host E_L (E_H), as well as their variances. Dopants with E_Ld<E_L (E_Hd>E_H) affect the diffusion-coefficient-to-mobility ratio mainly in the range of low and middle carrier concentrations, while those with E_Ld>E_L (E_Hd<E_H) have significant effect only in the range of high carrier concentrations. It was found that there can be a maximum in the dependence of the diffusion-coefficient-to-mobility ratio on the quasi-Fermi energy or carrier concentration exist, for appropriate values of the doping level, the mean energy and variance of LUMO or HOMO states of the dopant. PACS 71.20.Rv; 72.90.+y; 73.50.-h     

ABCD rule for Gaussian beam propagation in the context of quantum optics derived by the IWOP technique

The development of technique of integration within an ordered product (IWOP) of operators extends the Newton-Leibniz integration rule, originally applying to permutable functions, to the non-commutative quantum mechanical operators composed of Dirac’s ket-bra, which enables us to obtain the images of directly mapping symplectic transformation in classical phase space parameterized by [A, B; C, D] into quantum mechanical operator through the coherent state representation, we call them the generalized Fresnel operators (GFO) since they correspond to Fresnel transforms in Fourier optics. Based on GFO we find the ABCD rule for Gaussian beam propagation in the context of quantum optics (both in one-mode and two-mode cases) whose classical correspondence is just the ABCD rule in matrix optics. The entangled state representation is used in discussing the two-mode case.