Family symmetries and alignment in multi-Higgs doublet models

The exact alignment of the Yukawa structures on multi-Higgs doublet models provides cancellation of tree-level flavour changing couplings of neutral scalar fields. We show that family symmetries can provide a suitable justification for the Yukawa alignment.     

Possible candidate nuclei for chirality-parity quartet bands

The potential energy surfaces of the even-even~(68-92)Se,~(112-150)Ba,and~(208-230)Ra isotopes are calculated using the macroscopic-microscopic method in a multidimensional space{α_(λ,μ)}including quadrupole(λ=2,μ=0,2)and octupole(λ=3,μ=0,1,2,3)degrees of freedom.The calculated results show that the even-even isotopes~(92)Se,~(112,114,144-150)Ba and~(220-228)Ra can exhibit the coexistence of triaxial and octupole deformations,thereby leading to simultaneous chiral and reflected symmetry breaking.Therefore,chirality-parity quartet bands are expected in these and their neighboring odd-A/odd-odd nuclei.     

固体发动机尾焰近红外高光谱计算与仿真

首先介绍固体发动机尾焰中钾原子的来源及其在尾焰中的辐射机理,并基于原子谱线理论对尾焰钾共振双线的光谱线型特征进行分析。然后,采用理想模型及半经验公式法对尾焰流场分布进行数值模拟,通过尾焰的流场参数使用C-G近似法数值计算尾焰钾共振双线的辐射特性。最后,利用大气辐射传输模型计算尾焰中钾共振双线辐射信号经过大气传输后到达探测系统的光谱特征。结果表明,该方法能有效地仿真计算尾焰近红外钾线高光谱精细结构。仿真结果亦表明钾共振双线光谱信号能有效通过大气传输,可作为尾焰探测识别的依据。     

Photonic generation of ultrawideband signals by exploiting gain saturation of dark pump pulse with double undershoots in a highly nonlinear fiber

We have proposed and theoretically demonstrated an alternative photonic scheme to generate ultrawideband (UWB) doublet pulses based on gain saturation effect in one piece of highly nonlinear fiber (HNLF). A flexible format swap between UWB doublet and monocycle pulses can be successfully realized by properly tuning the optical tunable delay line (ODL). Moreover, the key parameters for UWB pulse, including the center frequency (Fc), 10 dB bandwidth (BW_10dB), and fractional bandwidth (FBW), are also investigated with Fc being Einstein shift when the doublet pulse transforms into the monocycle pulse. Finally, our proposed scheme exhibits good performance that the obtained UWB pulse can have a FBW of > 100% at the Fc of ~ 7 GHz and UWB-over-fiber technology is also implemented without dispersion management.     

UV resonance Raman study of TrpZip2 and related peptides: π‐π interactions of tryptophan

Aromatic interactions are important stabilizing forces in proteins but are difficult to detect in the absence of high‐resolution structures. Ultraviolet resonance Raman spectroscopy is used to probe the vibrational signatures of aromatic interactions in TrpZip2, a synthetic β‐hairpin peptide that is stabilized by edge‐to‐face and face‐to‐face tryptophan π‐π interactions. The vibrational markers of isolated edge‐to‐face π‐π interactions are investigated in the related β‐hairpin peptide W2W11. The bands that comprise the Fermi doublet exhibit systematic shifts in position and intensity for TrpZip2 and W2W11 relative to the model peptide, W2W9, which does not form aromatic interactions. Additionally, hypochromism of the B_b absorption band of tryptophan in TrpZip2 leads to a decrease in the relative Raman cross‐sections of B_b‐coupled Raman bands. These results reveal spectral markers for stabilizing tryptophan π‐π interactions and indicate that ultraviolet resonance Raman may be an important tool for the characterization of these biological forces. Copyright © 2012 John Wiley & Sons, Ltd.     

Radiative Decay Bc→ Ds*γ in the Technicolor with a Massless Scalar Doublet Model

Applying perturbative QCD, we study the process B_c→D_s^*γ in the technicolor with a massless scalar doublet model (TCMLSM). There are mainly two mechanisms contributing to the B_c→ D_s^*γ process. One proceeds through the short distance b→sγ transition and the other through weak annihilation accompanied by a photon emission. We find that, compared with the standard model, the modification of B_c→ D_s^*γ from π_p (the physical pions in the TCMLSM) is so small that can be neglected for the allowed mass of π_p. The weak-annihilation contribution is found to be about one order larger than that of the electromagnetic penguin diagrams.