中心波长为28.5nm多层膜镜反射率测量

在“星光-Ⅱ”装置上以类Ne铬x射线激光作为标定源，以平场光栅谱仪为分光元件进行了285nm的Mo/Si多层膜反射镜效率测量.介绍了实验方法，给出了实验结果，本次研制的两块多层膜镜反射率分别为31%和9.6%. 关键词： x射线多层膜反射镜 反射率测量 x射线激光     

光网络中基于预定组播业务的资源优化

文章利用遗传算法安排光网络中预定组播业务的计算顺序,提出了优化业务顺序的分层图算法和点着色算法,并与按时间顺序安排业务的算法进行了比较.仿真表明,优化排序后,资源优化效果明显.在波长数的优化上,分层图算法比点着色算法性能更好.在分层图算法中,业务放置顺序的优化对组播树总链路数的减少也有一定帮助.     

FT-IR and 2D-IR spectroscopic studies on the effect of ions on the phase separation behavior of PVME aqueous solution.

Thermosensitive phase transition behavior of poly(vinyl methyl ether) (PVME) in an aqueous solution and the effect of inorganic ions on the coil-globule transition have been investigated by Fourier transform infrared (FT-IR) spectroscopy with attenuated total reflection (ATR) accessory. ATR-IR spectra of PVME aqueous solution indicate that in water-PVME-inorganic salts system, the phase separation temperature of PVME aqueous solution decreased with the increase of ion concentration and the increase of anion electronegativity. Meanwhile, two-dimensional infrared (2D-IR) measurements have been made to clarify the microcosmic conformational changes of PVME during the coil-globule transition. Results show that the conformation changes of main chains occur earlier than those of ether groups during heating. Furthermore, the 2D correlation spectroscopy of PVME aqueous solution during heating and the increase of concentration of potassium chloride have been studied. The features of 2D-IR spectra during heating did not change compared to the features of PVME aqueous solution during the increase of concentration of potassium chloride. This result implies that, although the addition of inorganic ions shifts the phase separation temperature, it does not alter the internal mechanism of the coil-globule transition of PVME.     

Radiolocation in CDMA Cellular System Based on Joint Angle and Delay Estimation

This paper considers the problem of wireless location in code-divisionmultiple-access (CDMA)cellular system. Through the method of jointly estimating angle of arrival(AOA) and time ofarrival (TOA), a novel scheme is proposed for radiolocation in multipathenvironment, especiallywhen line-of-sight (LOS) path is not available to every base station involvedin location servicefor a mobile subscriber. The Cramer-Rao bound (CRB) is derived for the jointestimator. Based onsimulation results, the accuracy of the proposed wireless location scheme inCDMA system is assessed.     

Resolution of overlapping echoes and constrained matched filter

An algorithm for the resolution of overlapping echoes is proposed based on the constrained matched filters (CMF) that maximize the signal to noise ratio (SNR) for a desired signal-and cancel out other unwanted signals. The CMP is equivalent to the maximum likelihood detection and asymptotically identical to the optimum detector of signal from interference. The resolution capability of the algorithm breaks the classical resolution limit in the time domain     

群众决策的ακ-较多规则

对于群体决策问题,本文给出一个新的带参数的ακ-较多规则,并且讨论了在此规则下个体选优解和群体选优解的关系。此外,还论证了相应的ακ-较多规则满足Arrow公理的情况。     

安全防火墙的设计

文章主要讨论了防火墙设计的安全策略以及国外产品的最新性能比较。     

实验与探索

现代科技发展要求学生具有独立探索知识的能力,因此,教师必须帮助学生养成自主探究的习惯.实验教学不仅仅是为了验证某个定律,更重要的是如何利用实验教学生学会探索,学会研究,进行创造性学习.1 利用演示实验让学生感受探究的乐趣 布鲁诺指出:“学习的最好刺激乃是对科学材料的兴趣.”杨振宁教授也曾指出:     

Isolated-utterance speech recognition using hidden Markov modelswith bounded state durations

Hidden Markov models (HMMs) with bounded state durations (HMM/BSD) are proposed to explicitly model the state durations of HMMs and more accurately consider the temporal structures existing in speech signals in a simple, direct, but effective way. A series of experiments have been conducted for speaker dependent applications using 408 highly confusing first-tone Mandarin syllables as the example vocabulary. It was found that in the discrete case the recognition rate of HMM/BSD (78.5%) is 9.0%, 6.3%, and 1.9% higher than the conventional HMMs and HMMs with Poisson and gamma distribution state durations, respectively. In the continuous case (partitioned Gaussian mixture modeling), the recognition rates of HMM/BSD (88.3% with 1 mixture, 88.8% with 3 mixtures, and 89.4% with 5 mixtures) are 6.3%, 5.0%, and 5.5% higher than those of the conventional HMMs, and 5.9% (with 1 mixture), 3.9% (with 3 mixtures) and 3.1% (with 1 mixture), 1.8% (with 3 mixtures) higher than HMMs with Poisson and gamma distributed state durations, respectively