内孔缝位置对嵌套腔体微波耦合特性的影响

 利用时域有限差分（FDTD）方法计算了不同内孔缝位置情况下微波脉冲与带缝嵌套圆柱形腔体系统的耦合过程；分别分析了内孔缝位置对外部带缝腔体和内部带缝腔体耦合特性的影响。结果表明:除了内孔缝附近区域以外，内孔缝位置对外腔耦合特性的影响很小，可以忽略不计；但内孔缝位置对内腔耦合特性的影响较大，而且内腔的屏蔽性能由外腔内的耦合场分布以及内孔缝的位置共同决定。     

Strongly Correlated Effect in TiS2

The thermoelectric compound TiS2 is studied by using the full-potential linearized augmented plane-wave method on the density functional theory with the generalized gradient approximation （GGA） as well as the on-site Coulomb interaction correction （＋U）. The Seebeck coefficient of TiS2 is calculated based on the electronic structure obtained within the GGA under the consideration of the on-site Coulomb interaction. The calculated Seebeck coefficient at 300K shows that Coulomb interaction U in the range of 4.97-5.42eV is important to reproduce the experimental data. The obtained energy gap Eg around 0.05 eV indicates that TiS2 is an indirect narrow-gap semiconductor.     

Speech enhancement based on multitaper spectrum and psychoacoustical weighting rule

Multitaper spectrum has lower variance than the traditional periodogram. The noise spectrum and the noise to noisy signal spectrum ratio (NNSR) were estimated from the multitaper spectrum of the noisy signal; the pre-enhanced speech for calculating the noise masking threshold was obtained by the spectral amplitude subtraction method, whose gain is a function of NNSR; the final enhanced speech was obtained by suppressing the Fourier spectrum of the noisy speech with the psychoacoustical weighting rule incorporating the noise masking threshold. Because of the low variance feature of the multitaper spectrum, a modified offset formula was proposed to calculate the noise masking threshold, thus the reconstructed speech with this modification has an improvement in MBSD (Modified Bark Spectral Distortion). When a maximum limitation less than one to the psychoacoustical weighting rule is further proposed, the higher the input SNR (> 0 dB) is, the more improvement the segmental SNR and the overall SNR have. The informal listening tests show that there is little speech distortion for the enhanced speech processed by the proposed method, the background noise is reduced much and free of musical noise.     

CO分子d^3Δ—α^3П三重带的塞曼调制磁旋转光谱的研究

采用塞曼调制磁旋转光谱研究ＣＯ分子（ｄ＾３Δ－α＾３П）的（５－０）振动带高灵敏度吸收谱。标识出了十二个子带，观察到了下态α＾３П的Λ双分裂，拟合出了上下态分子常数。     

Bs Semileptonic Decays to Ds and D^＊8 in Bethe-Salpeter Method

Using the relativistic Bethe-Salpeter method, the electron energy spectrum and the semileptonic decay widths of B^0 → Ds^- e＋ve and B^0 → Ds^＊-e＋ve are calculated. We obtain a large branching fraction Br（Bs → Dseve） = （2.85 ± 0.35）% and Br（Bs→ D^＊s eue） = （7.09 ±0.88）%, which can be easily detected in future experiments.     

紧致带边黎曼流形上的Ricci形变

研究n维紧致带边流形的Ricci形变问题，得到在如下拼脐奈件下｜W｜^2＋｜V｜^2≤1/3（n-2）｜U｜^2,则（M，g）在Ricci流下可形变为（M，g∞），使得（M，g∞）具有常正曲率和全测地边界．     

用“找规律”重新认识“辗转相除法”

<正>辗转相除法最早出现于古希腊欧几里得《几何原本》的第Ⅶ章,其主要作用在于给出了求两个正整数最大公因数的一般方法.比如,要求198和252的最大公因数,运用辗转相除法的计算过程为     

具有弱正规幂等元的rpp半群的结构

研究一类特殊的rpp半群，即含弱正规幂等元的rpp半群。作者首先给出了这类半群的若干特征，然后通过右正规带和具有某些相应性质的rpp半群建立了具有弱正规幂等元的rpp半群的结构。把郭小江在富足半群上得到的结果进行了很好的推广和发展。另外，（弱）正规幂等元与目前颇受重视的另一个概念一适当断面（adequatetransversal）有着密切的联系。自然，开展具有弱正规幂等元的各种半群的研究是有意义的。     

用等值宽度法测量fs脉冲宽度

本文提出利用等值宽度测量fs光脉冲持续时间的方法.给出了脉冲形状为sech~2 (t/T)、exp(-2t~2/T~2)和exp(-2|t|/T)的干涉相关曲线上包络与相应二阶强度相关曲线半宽度等值的位置,它们分别是3.984、4.875和4.928.定义了两种相关测量的临界延迟速度.理论分析与实验结果符合得很好.所得结果表明,该测量方法可将常规超短脉冲相关测量的时间分辨率提高几倍至几十倍.