Electron Capture and Dissociative Excitation in Slow Collisions of Na+ and K+ Ions with Hydrogen and Nitrogen Molecules

Absolute cross sections of electron capture and dissociative excitation for the Na⁺-H₂, N₂ and K⁺-H₂, N₂ pairs are determined. The high intense hydrogen and nitrogen atomic lines HI (121.6 nm) NI (120.0 nm), have been observed. For the Na⁺-H₂ and K⁺-H₂ pairs the qualitative interpretation of experimental results in the framework of quasidiatomic approximation are carried out. This revised version was published online in July 2006 with corrections to the Cover Date.     

顶色辅助的多标度人工色理论对稀有过程e~ e~-→s的单圈效应

讨论了顶色辅助的多标度人工色理论预言的赝标哥尔斯通玻色子（ｔｅｃｈ－ ｎｉｐｉｏｎｓ,ｔｏｐ－ｐｉｏｕｓ）对稀有过程ｅ＋ｅ－→ｂｓ的单圈效应,计算了该过程在ＬＥＰⅡ上 的产生截面,得到较标准模型预言值要大一个数量级的数值结果．并进一步讨 论了在Ｂ介子工厂上探测此稀有过程的可能性．     

The approximate analytical solution for the buckling loads of a thin-walled box column with variable cross-section

1.IntroductionThin-walledboxcolumnswithvariablecross-sectionareextensivelyusedascompressionmembersforhighbridgepiers,waterandtelevisiontowersandothersimilarstructures.Atpresent,however,fewpapersdealingwiththecriticalloadsoftorsional-fie-curalbucklingforthiskindofstructurescanbeseen.Inthispaper,bymeansoftheenergyprincipleandtheGalerkin'smethod,theapproximateexpressionsforcalculatingthecriticalloadsoffie-curalandtorsionalbucklingaredevelopedrespectively.Anapplicablecomputerprogramisworkedout,an…     

Nd:GGG晶体荧光寿命的测试及受激发射截面的计算

介绍了荧光寿命的测试原理.设计了荧光寿命测试系统.利用脉冲取样技术测试了Nd:GGG晶体的荧光寿命,约为250μs.采用英国的荧光光谱仪,在室温条件下,用波长为488nm的Ar离子激光器激发Nd:GGG晶体,获得了Nd:GGG晶体的荧光光谱,计算出的Nd:GGG晶体的受激发射截面σ(λ)为21.57×10-20cm2.     

High frequency doubling efficiency THz GaAs Schottky barrier diode based on inverted trapezoidal epitaxial cross-section structure

A high-performance terahertz Schottky barrier diode (SBD) with an inverted trapezoidal epitaxial cross-sectional structure featuring high varactor characteristics and reverse breakdown characteristics is reported in this paper. Inductively coupled plasma dry etching and dissolution wet etching are used to define the profile of the epitaxial layer, by which the voltage-dependent variation trend of the thickness of the metal-semiconductor contact depletion layer is modified. The simulation of the inverted trapezoidal epitaxial cross-section SBD is also conducted to explain the physical mechanism of the electric field and space charge region area. Compared with the normal structure, the grading coefficient M increases from 0.47 to 0.52, and the capacitance modulation ratio (C_max/C_min) increases from 6.70 to 7.61. The inverted trapezoidal epitaxial cross-section structure is a promising approach to improve the variable-capacity ratio by eliminating the accumulation of charge at the Schottky electrode edge. A 190 GHz frequency doubler based on the inverted trapezoidal epitaxial cross-section SBD also shows a doubling efficiency of 35% compared to that 30% of a normal SBD.