环境的作用与量子力学的破坏

 量子力学是描写尺度在普朗克常数量级的微观体系的理论,它被我们在广阔范围内的观察所肯定和证实.我们有理由相信量子力学应是讨论微观体系性质的基础.从量子力学扩展到量子场论,正如德布罗意多年前评述的     

常微分方程奇解的讨论

对常微分方程教科书中采用的不同方式来定义奇解进行了讨论，指出了用包络定义奇解的不相容性和用唯一性被破坏定义奇解的合理性。     

光学材料破坏机理

本文综述近三十年来国内外光学材料破坏研究发展状况，详细地阐述了表面破坏，杂质缺陷引起的热破坏，受激布里渊散射激发超声波造成的破坏，雪崩电离击穿和多光子吸收电离破坏，以及自聚焦引起的破坏的机理，及其各自的理论模型。     

τ轻子物理

 粒子物理学中所研究的粒子,如果按照它们自身所具有的相互作用力来划分,可以分为强子和轻子两大类,各种相互作用的性质是十分不同的,具有了某一种相互作用力的粒子就会按照这种相互作用力的性质发生衰变、反应过程,强子具有强相互作用力,电磁相互作用力和弱相互作用力。但是,轻子就只具有电磁相互作用力(如果它带有电荷的话)和弱相互作用力。所以,强子和轻子的各种行为是十分不同的。     

紫外Sc_2O_3薄膜的光学和结构性能表征及其激光作用下的损伤机理

利用电子束蒸发方法,在不同沉积温度(50~350℃)下制备了Sc2O3薄膜。分别用分光光度计,小角掠入射X射线衍射仪和轮廓仪测试了薄膜样品的光谱、微结构和表面粗糙度信息,并用薄膜分析软件Essential Macleod计算了Sc2O3薄膜的折射率和消光系数。结果表明:随着沉积温度升高,Sc2O3薄膜结晶程度增强,晶粒尺寸增大,且较高的沉积温度有利于获得较高的折射率。最后用355 nm,8 ns的三倍频Nd:YAG激光器测试了其激光损伤阈值(LIDT),最大值为2.6 J/cm2,且阈值与薄膜的消光系数、表面粗糙度、光学损耗均呈现相反的变化趋势。用光学显微镜和扫描电子显微镜表征了该薄膜的破坏形貌,详细分析了薄膜在不同激光能量作用下破坏的发展过程,以及Sc2O3薄膜在355 nm紫外激光作用下LIDT与制备工艺的关系,重点分析了355 nm激光作用下薄膜的破坏机理。     

Study of scalar meson a0（980） from B → a0（980）π decays

In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employing the perturbative QCD （pQCD） factorization approach at the leading order. We found that （a） the pQCD predictions for the branching ratios are around （0.4-2.8） × 10^-6, consistent with currently available experimental upper limits; （b） the CP asymmetries of B^0→ a0^0（980）π^0 and B^- → a0^- （980）π^0 decays can be large, about （70-80）% for α= 100°.     

B→（J/ψ,η_c）K decays in the perturbative QCD approach

In this paper,we calculated the B →（J/ψ,ηc） K decays in the perturbative QCD（pQCD） factorization approach with the inclusion of the partial next-to-leading order（NLO） contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors：Br（B0 → J/ψK0） = 5.2-＋32..58×10-4,Br（B＋ → J/ψK＋） = 5.6-＋32..79×10-4,Br（B0 →ηcK0） = 5.5-＋22..30 × 10-4,Br（B＋ →ηcK＋） = 5.9-＋22..51 × 10-4.     

Dynamic Fracture Toughness and Failure Mechanisms of ZnO Whiskers Secondary Reinforced Composites

Quasi-static and dynamic fracture properties and damage mechanism of glass fiber polymer composites embeaaea with different mass percentages of ZnO whiskers are investigated by using an Instron Testing machine and a Split- Hopkinson pressure bar. According to the experimental results and linear fracture mechanics, the quasi-static fracture toughness Kic and the dynamic fracture toughness Kid under various impact velocities of specimens are obtained. Fracture mechanism is investigated by fractography analysis with a scanning electron microscope. The experimental results show that the mass percentage of ZnOw has little influence on the quasi-static fracture toughness, but a little influence on the dynamic fracture toughness and time of initial fracture point of specimens by the reason of various fracture mechanisms.     

CP Violation in ∧b → ∧l^＋l^- Decay in the Four-Generation Standard Model

We present the first study of CP asymmetry in ∧b → ∧l^＋l^- decay when a new weak phase comes through the extension of three-generation standard model to the four-generation standard model. Taking ｜Vt′s^＊Vt′b｜ = 0.01, 0.02, 0.03 with phase {60° - 120°}, which is consistent with the b → sl^＋l^- rate and the Bs mixing parameter △mBs, we find out that CP asymmetry is quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, in particular, to search for the fourth generation quarks （t′, b′） via their indirect manifestations in loop diagrams.