The 1/f noise in multiwalled carbon nanotubes

The $1/f$ noise in multiwalled carbon nanotubes bundles has been investigated between the frequency range of 0.1 to 30 Hz. At room temperature the noise spectrum is standard 1/f, and its level is proportional to the square of the bias voltage. With decreasing temperature the noise level also decreases. At 4.2 K the noise level follows a non-monotonic dependence against the bias voltage, showing a peak at a certain bias voltage, meanwhile its frequency dependence also deviates from the 1/f trend. This anomalous behaviour is discussed within the picture of environmental quantum fluctuation of charge transport in the samples.     

热氢原子碰撞导致的CO2(v3)的高振动激发

用时间分辨-傅里叶变换红外发射光谱研究了热的氢原子与C02分子间高效率的平动—振动(T—V)能传递．热的氢原子由ArF激光光解H2S得到，这种氢原子的平动能为223kJ／mo1。实验中观察到了从2130cm^-1到2400cm^-1的红外发射谱带，它归属于高振动激发的CO2分子的非对称伸缩振动(v3)．对这一发射谱带的光谱拟合显示CO2的非对称伸缩振动被激发到了较高的振动态，振动量子数达到了v=7。并且有5580cm^-1的能量经传能过程由氢原子到达了CO2的v3模。实验条件下氢原子与C02的T—V传能效率为0.30。实验结果与Schatz等人的用3D半经典计算预测的碰撞截面符合的很好．     

Preprocessing rules for integer programming solutions to the generalised assignment problem

Several preprocessing rules to reduce integer programming problem size are proposed and examined for the generalised assignment problem. The rules make use of the linear programming relaxation and ranking on the basis of a combined resource/cost metric. Computational experiments with commercial branch and bound solvers have been performed using publicly available problem data from the OR library. Results are promising as the preprocessed problem solves to within 1% of the full problem with significantly less CPU time for most of the test problems examined.     

掺锌LiNbO3晶体的生长及其光学性能

在LiNbO₃中掺进3mol%、5mol%、7mol%ZnO生长Zn:LiNbO₃晶体.测试Zn:LiNbO₃晶体的吸收光谱,研究Zn:LiNbO₃晶体吸收边紫移的机制.测试Zn:LiNbO₃晶体的红外光谱,研究Zn(7mol%):LiNbO₃晶体OH 吸收峰由3484cm^-1移到3530cm^-1的机制.测试Zn:LiNbO₃晶体倍频转换效率和相位匹配温度,研究Zn:LiNbO₃晶体倍频转换效率增强的机制.     

Based algebras and standard bases for quasi-hereditary algebras

Quasi-hereditary algebras can be viewed as a Lie theory approach to the theory of finite dimensional algebras. Motivated by the existence of certain nice bases for representations of semisimple Lie algebras and algebraic groups, we will construct in this paper nice bases for (split) quasi-hereditary algebras and characterize them using these bases. We first introduce the notion of a standardly based algebra, which is a generalized version of a cellular algebra introduced by Graham and Lehrer, and discuss their representation theory. The main result is that an algebra over a commutative local noetherian ring with finite rank is split quasi-hereditary if and only if it is standardly full-based. As an application, we will give an elementary proof of the fact that split symmetric algebras are not quasi-hereditary unless they are semisimple. Finally, some relations between standardly based algebras and cellular algebras are also discussed.     

鱼洗振型浅析

本在普通物理的层次上建立鱼洗的物理模型，应用柱面坐标的波动方程和模拟鱼的简化边界条件解出其自激振荡振型，与应用激光全息手段拍摄的鱼洗振型基本一致亦与锤击实验中测得的鱼洗侧壁位移相符，从而初步揭示了鱼洗的喷水机理。     

Synthesis of Highly Branched Poly（ε-caprolactone） by Self-condensing Atom Transfer Radical Polymerization of Macroinimers

Fréchet et al.1 in 1995 prepared hyperbranched vinyl polymers by the technique named self-condensing vinyl polymerization (SCVP) of initiator-monomers (“inimers”) having the general structure AB*, where A stands for a double bond and B* for an initiati…     

活性炭分离-桑色素荧光法测定天然水中痕量铍

在溴化十四烷基吡啶存在下,铬天菁S与铍生成三元胶束络合物。在pH10.0氨～氯化铵缓冲介质中,活性炭定量吸附此络合物,用热盐酸洗脱铍,可与其他干扰离子分离,用桑色素荧光法进行测定。该法用于测定美国EPA标准水样和天然水中的痕量铍,结果令人满意。     

Dynamics of laser-induced shock wave by optical probe in air

A new simple optical system based on optical beam deflection combining the holophote corner cube was developed in order to study the dynamics of laser-induced shock waves in air. In this method, we adopt a He-Ne laser beam as the detection beam. The He-Ne laser beam, reflected by corner cube, intersects the propagating shock wave at two successive positions. The measurement of the shock wave velocity benefits from the double peak signals induced by the same acting laser pulse, which is calculated from the time interval between the corresponding oscilloscope signals and the distance of the two He-Ne laser beams. By virtue of this setup, we are also able to determine the pressure of the generated shock waves. It is shown that this method is simple with a fairly good precision and is much easier than the conventional methods used for this task.     

Laser induced damage of multi-layer dielectric used in pulse compressor gratings

Laser induced damage threshold (LIDT) of multi-layer dielectric used in pulse compressor gratings (PCG) was investigated. The sample was prepared by e-beam evaporation (EBE). LIDT was detected following ISO standard 11254-1.2. It was found that LIDTs of normal and 51.2°incidence (transverse electric (TE) mode) were 14.14 and 9.31 J/cm2, respectively. A Nomarski microscope was employed to map the damage morphology, and it was found that the damage behavior was pit-concave-plat structure for normal incidence, while it was pit structure for 51.2°incidence with TE mode. The electric field distribution was calculated to illuminate the difference of LIDT between the two incident cases.