Z′ mediated flavor changing neutral currents in B meson decays

We study the effects of an extra U(1)′ gauge boson with flavor changing couplings with fermion mass eigenstates on certain B meson decays that are sensitive to such new physics contributions. In particular, we examine to what extent the current data on B_d→φK and B_d→η′K decays may be explained in such models, concentrating on the example in which the flavor changing couplings are left-chiral. We find that within reasonable ranges of parameters, the Z′ contribution can readily account for the anomaly in S_φKS but is not sufficient to explain large branching ratio of B_d→η′K with the same parameter value. S_φKS and S_η′KS are seen to be the dominant observables that constrain the extra weak phase in the model.     

一种微穿孔板消声器

本文根据马大猷教授提出的“微穿孔板吸声体精确理论”，在对微穿孔板消声器结构参数与吸声特性之间的相互影响进行了分析的基础上，设计了微穿孔板消声器并将其应用在新舟60飞机APU(辅助动力装置)降噪的实际工程中，并通过编写的噪音数据采集分析程序，对降噪效果进行了测试和分析，验证出微穿孔板消声器对消除飞机的APU的排气噪声具有良好的消声效果，平均降噪7．16dB。     

Smoothing estimation of rate function for recurrent event data with informative censoring

This paper proposes kernel estimation of the occurrence rate function for recurrent event data with informative censoring. An informative censoring model is considered with assumptions made on the joint distribution of the recurrent event process and the censoring time without modeling the censoring distribution. Under the validity of the informative censoring model, we also show that an estimator based on the assumption of independent censoring becomes inappropriate and is generally asymptotically biased. To investigate the asymptotic properties of the proposed estimator, the explicit form of its asymptotic mean squared risk and the asymptotic normality are derived. Meanwhile, the empirical consistent smoothing estimator for the variance function of the estimator is suggested. The performance of the estimators are also studied through Monte Carlo simulations. An epidemiological example of intravenous drug user data is used to show the influence of informative censoring in the estimation of the occurrence rate functions for inpatient cares over time.     

Constituents of Antrodia Cinnamomea

We describe identification of seven components from Antrodia cinnamomea. Their structures were determined on the basis of spectral analysis and comparison with authentic samples. These compounds include two steroids (1, 2) (β-sitosterol and eburicol), two new steroids (3, 4) [methyl-4α-methylergost-8,24(28)-dien-3,7,11-trion-26-oate and methyl-4α-methylergost-8,24(28)-dien-3,11-dion-26-oate], two lignans (5, 6) [(+)-sesamin and 4-hydroxysesamin], and one long chain methyl ester (7) (methyl oleate). Among them, compounds 3 and 4 are first isolated from nature.     

Theoretical Study of the Molecular Electrostatic Potential of C_(50)

1 INTRODUCTION All fullerenes made so far obey the isolated pentagon (IPR)[1], which governs the stability of fullerenes comprising hexagons and exact 12 pen- tagons. Smaller fullerenes, which violate the IPR, are predicted to have high instability and especially difficult isolation due to their condensed pentagons and increased strain. The production of smaller fullerene C36 has been reported[2]. However, the definite characterization of a C36-based solid is in doubt. Moreover, variou…     

Analysis of Corrugated Long-Period Gratings in Planar Waveguides and Their Polarization Dependence

We present a theoretical analysis of corrugated long-period gratings in planar waveguides. In particular, we calculate the transmission spectra for both the TE and TM polarizations and highlight the polarization-independence conditions.     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

Study of ferromagnetism–superconductivity interactions in Co/Nb multilayers

We investigate Co/Nb multilayers to explore the spontaneous π-phase shift between the superconducting (SC) layers, which is attributed for causing the non-monotonic change of the SC transition temperature (T_c) with the ferromagnetic (FM) layer thickness (t_FM) in several FM/SC multilayered systems. The issue of interfacial roughness is also explored by growing Co/Nb multilayers at various sputtering pressures. Transport measurements show a non-monotonic dependence of T_c on t_FM, and this dependence is insensitive to the structural variation present in the samples, as measured by X-ray scattering.