贝塞尔-高斯脉冲光束在色散介质中的时间和光谱特性

 对等衍射长度贝塞尔-高斯脉冲光束在色散介质中的时间和光谱特性作了研究，结果表明，通过选择适当的空间参数，贝塞尔-高斯脉冲光束沿轴上传输时，脉冲宽度不变。传输距离小于无衍射长度时，随衍射角增加，功率谱形状未变，脉冲波形保持不变；传输距离大于无衍射长度时，随衍射角增加，光谱由蓝移变为红移，脉冲展宽。     

正项等差数列的不等式

由正项等差数列构成的不等式 ,叫做正项等差数列的不等式 .本文研究这样的一类不等式 .为了叙述简便 ,本文规定 {ａｎ}是公差为ｄ(ｄ >0 )的正项等差数列 ,Ｓｎ 是它的前ｎ项和 ,ｍ ,ｎ ,ｋ都是正整数 .定理 1　 1+ ｍｄｋａ11+ ｍｄｋａ2 ·…· 1+ ｍｄｋａｎ ≥ａｍ + 1ａｍ + 2 ·…·ａｍ +ｎａ1ａ2 ·…·ａｎ1ｋ.(当且仅当ｋ =1时等号成立 )证　由二项式定理得1+ ｍｄｋａｉｋ=1+Ｃ1ｋｍｄｋａｉ +Ｃ2 ｋｍｄｋａｉ2 +… +Ｃｋｋｍｄｋａｉｋ ≥ 1+Ｃ1ｋｍｄｋａｉ =1+ ｍｄａｉ=ａｉ+ｍｄａｉ=ａｍ +ｉａｉ,(当且仅当ｋ =1时取等号 …     

AAS测定纸巾中的铅和镉

本文采用原子吸收光谱法测定纸巾中铅、镉的含量。结果表明，不同纸巾中的污染元素铅、镉的含量不同。同时还对一种纸巾的铅、镉元素进行了回收实验，回收率在92％-104％之间。     

Structural and Electrical Characteristics of Pb（Zr0.53,Ti0.47）O3 Thin Films Deposited on Si （100） Substrates

Pb(Zr0.53, Ti0.47)O3 (PZT) films were directly deposited on Si substrates without a buffer layer by pulsed laser deposition. Only(110)-oriented PZT peaks (other than Si substrate peaks) were observed from the XRD data. The electrical properties of the PZT/Si capacitor were characterized in terms of both the capacitance versus voltage (C-V) and current versus voltage (I-V) measurements. The clockwise trace of the C-V curve shows ferroelectric polarization switching, as is expected. From the I-V curves, the Schottky emission and spacecharge-limited-current behaviour are found to be the mainly leakage current mechanism in a certain electric field range in the negative and positive bias, respectively.     

类铍离子低激发态等电子系列的能量、精细结构和超精细结构

采用多组态相互作用方法及Rayleigh-Ritz 变分方法，并考虑相对论修正和质量极化效应，获得了类铍离子等电子系列（Z=4-10）低激发态1s²2p2p ¹D^e和1s²2p3p ³P^e的相对论能量。同时还计算了精细结构和超精细结构。计算结果与其他理论和实验符合的很好。     

非晶金刚石膜的性能及其应用

非品金刚石薄膜具有超高硬度等一系列优异的特殊性能，为工程界孜孜追求的材料表面镀膜。用百纳科技公司研发制造的过滤阴极真空电弧离子镀膜机镀制的非晶金刚石薄膜，SP^3金刚石结构量≥80％，硬度高，膜／基结合力高，摩擦系数小，耐磨损，耐腐蚀，透光率高，在电子，机械，光学，生物医学上有广泛应用前景。我们已在视窗玻璃，丝锥，模具，硬质合金刀头等产品上成功应用。     

Quasielastic Scattering of the Halo Nucleus ^6He at 25 MeV／u from a ^9Be Target

The differential cross sections of quasielastic scattering of a 25 MeV/u ^6He from ^9Be target have been measured.The double-folding model approach is applied to generate the real part of the optical potential. The imaginary potential parameters as well as some of the real potential parameters are studied in comparison with the experimental data. The effect of the unstable nucleus is discussed.     

Dissociation and Coulomb Explosion of H2^4＋ in S^q＋ ＋H2 Collisions

We have investigated fragment emission from molecularions in H2^r collisions between S^q and H2 with incident energies of 12.5, 15.625, 18.75, 21.875, 25, 28.125, 31.25, 34.375, 37.5, 40.625, and 43.75 keV/u, respectively. The energy distributions of the fragments are measured by time-of-flight techniques. The experimental results show evidences for molecular Coulomb explosion and dissociation. A program[1] is estab-lished based on the Monte Carlo technique to simulate the time-of-flight spectrum of fragment ions with different initialkinetic energy in ion-Molecule collisions. Simulations are done for S^2 H2 collisions and compared with experimental results.     

两角和差三角函数在高考中的新特点

两角和差的三角函数是历年高考必考的内容之一 ,试题的形式有“选择、填空、解答” ,试题的难易程度均属中等水平 ,试题考查的知识点较多 ,从近几年试题来看 ,通过一个题目考查多个知识点的题目呈上升趋势 ,同时又呈现出下面新的特点 :①结合图象考查函数的性质 ;②试题的综合性有所加强 ;③试题的考点有所拓宽 ;④试题注重运用探究性思维 ;⑤试题更注重三角的工具性作用 .下面笔者就近几年的高考试题 ,例谈这些新特点 ,供参考 .一、结合图象考查函数的性质与图象结合考查函数性质在其它函数中考查较为常见 ,但出现在三角函数中较少 ,可在近…