e+e－→W+W－→h's过程中的色重组

用色等效哈密顿研究了e⁺e^－→W⁺W^－→h＇s过程中部分子阶段的色重组几率,并与Gustafson和Sjostrand等人的结果作了分析比较,发现色重组几率不能被忽略,并指出研究色重组对发展强子化模型提出了新的要求.     

综合题新编选登

题173已知△ABC的三边长是a,b,c,非负实数m,p满足等式:aa m bb m=cc p,试比较m,p的大小,并求m,p中较大者的最小值.解[方法1]由条件:aa m bb m=cc p求解p,c pc=m2 (a b)m ab(a b)m 2ab p=c(m2-ab)(a b)m 2ab(1)作差比较:m-p=m-c(m2-ab)(a b)m 2ab=(a b-c)m2 2abm abc(a b)m 2ab.因为a,b,c是△ABC的三边长,∴a b>c,∴a b-c>0.又m≥0故有上式大于零,即m-p>0,所以m>p.又由于p≥0,由(1)得:m2-ab≥0,m≥ab,∴max{m,p}=m的最小值为ab,此时p=0.[方法2]∵aa m bb m>aa b m ba b m=a ba b m=11 ma b>11 mc=cc m,∴cc p>cc m m>p.求m的最小值同上.[…     

生长条件和退火对金刚石薄膜光学性质的影响

提出一种分析微波等离子体化学气相沉积工艺条件对金刚石薄膜的组成和光学性质影响的方法。采用红外椭圆偏振光谱仪来分析Si衬底上金刚石薄膜的组成和光学性质，研究微波等离子体化学气相沉积法生长条件和退火工艺对金刚石薄膜的消光系数和折射率的影响。实验表明金刚石薄膜中存在C—H、C=C、O—H和C=O键，生长条件对薄膜中C—H和C=C键的含量及薄膜的折射率影响较大；薄膜经过退火后薄膜的光学性质得到明显改善。     

Isospin Momentum-Dependent Interaction and Its Role on the Isospin Fractionation Ratio in Intermediate Energy Heavy Ion Collisions

We investigate the role of isospin momentum-dependent interaction on the isospin fractionation ratio and its dynamical mechanism in the intermediate energy heavy ion collisions, by inserting an isospin degree of freedom into the momentum-dependent interaction to obtain an isospin momentum-dependent interaction given in a form practically usable in the isospin-dependent quantum molecular dynamics model. It is found that the isospin momentum-dependent interaction brings an important isospin effect into the isospin fractionation ratio. In particular, the isospin momentum-dependent interaction reduces obviously the reduction of isospin fractionation ratio. Thus the isospin dependence of momentum-dependent interaction is thus important for studying accurately the equation of state of isospin asymmetry nuclear matter.     

试题研讨(22)

试题　 ( 2 0 0 4届第五次大联考试题 )已知平面上一定点 C( - 1 ,0 )和一定直线 l:x=-4,P为该平面上一动点 ,作 PQ⊥l,垂足为 Q,( PQ 2 PC)· ( PQ- 2 PC) =0 .( 1 )问点 P在什么曲线上 ?并求出该曲线方程 ;( 2 )点 O是坐标原点 ,A、B两点在点 P的轨迹上 ,若OA λ OB=( 1 λ) OC,求 λ的取值范围 .命题思想　向量与解几结合编题 ,能够很好地考查学生的综合水平 .在 2 0 0 3年高考中出现了此类题型 ,它是近期综合测试的一个热点内容 .原题解答　 ( 1 )由( PQ 2 PC)· ( PQ- 2 PC) =0得 PQ2 - 4PC2 =0 .设 P( x,y) ,则 (…     

The effect of SRS on pilot-tone detection technique in DWDM system

A math model that can describe the effect of stimulated Raman scattering (SRS) on pilot-tone detection technique is proposed.Through numerical simulation,it is shown that the effect of SRS could produce ghost-tones.The power of ghost-tones was larger for the channels separated further from the real-tone. The power ratio between real-tone and ghost-tones increases linearly with the increase of transmission length when propagation distance longer than 300 km.     

聚酰亚胺树脂粉在金刚石抛光片中的应用

本文介绍了聚酰亚胺树脂粉在金刚石抛光片中的应用。由于聚酰亚胺树脂耐热温度高和耐磨性好，由它制作的金刚石微粉抛光片具有使用寿命长、磨削效率高和被加工工件的表面粗糙度低等优点。ＴＧ－ＤＳＣ分析表明：聚酰亚胺树脂粉在３６０℃之前的热稳定性较好，固化温度选择在２３０℃。ＳＥＭ分析表明：在抛光过程中起磨削作用的主要是金刚石颗粒。如果树脂的耐磨性能差与耐热温度不高，金刚石颗粒过早地脱落是引起抛光片寿命不长与加工工件表面粗糙度高的主要原因。     

Novel photonic packet WDM ring networks with tunable transmitters and fixed receivers using multi-token protocol

In the past few years, the bandwidth requirement ofmodern telecommunication networks has an enormous in-crease. It is mainly due to the massive and ever increas-ing popularity of the internet and its related multime-dia applications. Dense wavelength division multiplexing(DWDM) technique has undoubtedly become the solu-tion to increase the capacity of long-haul wide area net-works and metropolitan area networks. The bottleneckof network transfers from links to nodes. The wavelengthrouter can…     

火炮扰动引起光电跟踪仪瞄准线抖动的原因及解决办法

本文对安装在火炮托架上光电跟踪仪瞄准线产生抖动的原因从两个方面进行了初步分析。并给出了光电跟踪仪内外方位抗火炮扰动力矩和转动隔离度传递函数。     

Newton方程周期解存在性的构造性证明

本文在条件n2≤α（t）≤gx（t，x）≤b（t）≤（n＋1）2下，构造性地证明了Newton方程x″（t）十g（t，x（t））＝0的2π－周期解的存在唯一性，证明过程同时提供了一种数值计算周期解的方法．