Gallium Nitride Room Temperature α Particle Detectors

Gallium Nitride （GaN） room temperature α particle detectors are fabricated and characterized, whose device structure is Schottky diode. The current-voltage （I- V） measurements reveal that the reverse breakdown voltage of the detectors is more than 200 V owing to the consummate fabrication processes, and that the Schottky barrier and ideal factor of the detectors are 0.64 eV and 1.02, respectively, calculated from the thermionic transmission model. ^241Am α particles pulse height spectra from the GaN detectors biased at -8 V is obviously one Gauss peak located at channel 44 with the full width at half maximum （FWHM） of 15.87 in channel. One of the main reasons for the relatively wider FWHM is that the air between the detectors and isotope could widen the spectrum.     

Topological Aspects in an Interacting Mixture of a Charged and a Neutral Superfluid in Neutron Stars

By making use of the decomposition of U（1） gauge potential theory and the C-mapping method we discuss a mixture of interacting neutral and charged Bose condensates, which is supposed to be realized in the interior of neutron stars in the form of a coexistent neutron superfluid and protonie superconductor. We propose that this system possesses vortex line knotted solitons and the topological charges of vortex lines are characterized by the winding numbers of the C-mapping. Furthermore the spatial bifurcation of vortices is also discussed.     

硅在cBN单晶合成中的行为

 实验制备了复合氮化物Li₈SiN₄，并对合成温度、合成时间、气流量等因素的影响以及产物的稳定性进行了讨论。研究了Li₈SiN₄作为触媒添加剂时硅在cBN单晶合成中的作用。结果表明：cBN晶体多为截角八面体，晶面致密光滑；硅参与cBN的合成反应，并以SiO₂的形式沉积在cBN表面。     

Structural and Optical Properties of Zinc Nitride Films Prepared by Pulsed Filtered Cathodic Vacuum Arc Deposition

Polycrystalline zinc nitride films are deposited on Coming 7059 glass substrates by pulsed filtered cathodic vacuum arc deposition （PFCVAD）. The crystallographic structure is studied by means of x-ray diffraction. These measurements show that all the films are crystallized in the cubic structure, in a preferred orientation along the （332） and （631） directions. Weak XRD signal shows small crystallites distributed in an amorphous tissue. A small improvement of crystallinity is observed with annealing. Optical parameters such as absorption, energy band gap, Urbach tail, extinction coefficients have been determined. The Urbach tail energy is decreased with annealing at 500℃ for one hour. Energy band gap values are found to be increased by annealing.     

B0d→φK*0极化反常和Bd→φKs CP不对称的研究

在模型Ⅲ下,仅考虑来自于中性规范玻色子H0,H0和A0产生的树图阶味改变中性流的贡献,并利用QCD因子化方法,对B0d→φK(≠)0衰变过程的极化反常和Bd→φKs衰变过程的CP不对称进行了研究,经过计算发现,在147＜|λbsλss|＜165的参数范围内,这两个过程中存在的反常现象能够同时给予解释.     

最小Higgs模型在ILC上可能的味改变物理迹象

在最小Higgs(LH)模型中, 由于引进了类矢量顶夸克T, 对弱作用流产生了新的影响. CKM矩阵从3×3变为4×3, 在树图下出现味改变中性流(FCNC). 本文研究了在国际高能直线对撞机(ILC)上能否通过e⁺e^－→tc+tc和e⁺e^－→WWν_eν_e→(tc+tc) ν_eν_e过程探测到LH模型所预言的FCNC信号.     

用振幅比值方法预言中性粲介子衰变到CP本征态的CP不对称性

用振幅比之方法计算了中性粲介子衰变到CP本征态的CP不对称性. 计算了时间相关和时间积分的CP不对称性. 结果表明, 时间积分的CP不对称参数约为千分之一的量级. 还讨论了在BESⅢ和B工厂上实验检验的可能性.     

Energy of a Polaron in a Wurtzite Nitride Finite Parabolic Quantum Well

The effects of electron-phonon interaction on energy levels of a polaron in a wurtzite nitride finite parabolic quantum well （PQW） are studied by using a modified Lee-Low-Pines variational method. The ground state, first excited state, and transition energy of the polaron in the GaN/Al0.3Ga0.7N wurtzite PQW are calculated by taking account of the influence of confined LO（TO）-like phonon modes and the half-spaee LO（TO）-like phonon modes and considering the anisotropy of all kinds of phonon modes. The numerical results are given and discussed. The results show that the electron-phonon interaction strongly affects the energy levels of the polaron, and the contributions from phonons to the energy of a polaron in a wurtzite nitride PQW are greater than that in an A1GaAs PQW. This indicates that ehe electron-phonon interaction in a wurtzite nitride PQW is not negligible.