Number albedo measurements from stratified layers of iron,concrete and aluminium

A layer of stratified combination composed of selected radiation shielding materials acquires better shielding property. Albedo is used in such measurements as an integral measure ofγ-ray scattering. The stratified slabs of alternating heterogeneous layers have been found to have a virtual homogeneous property with a definite effective atomic number. The angular distribution of back-scattered photons as well as the total number albedo values for iron, aluminium and concrete in stratified combination for 662 keV and 1250 keV photons are reported.     

Remarks on beyond leading order

In recent years a two-scale expansion was established to study reactions of the type NN→NNπ within chiral perturbation theory. Then the diagrams of some subclasses that are invariant under the choice of the pion field no longer appear at the same chiral order. In this Letter we show that the proposed expansion still leads to well defined results. We also discuss the appropriate choice of the heavy baryon propagator.     

Macroscopic non-equilibrium thermodynamics in dynamic calorimetry

What is really measured in dynamic calorimetric experiments is still an open question. This paper is devoted to this question, which can be usefully envisaged by means of macroscopic non-equilibrium thermodynamics. From the pioneer work of De Donder on chemical reactions and with other authors along the 20th century, the question is tackled under an historical point of view. A special attention is paid about the notions of frequency dependent complex heat capacity and entropy production due to irreversible processes occurring during an experiment. This phenomenological approach based on thermodynamics, not widely spread in the literature of calorimetry, could open significant perspectives on the study of macro-systems undergoing physico-chemical transformations probed by dynamic calorimetry.     

在ILC上用γγ→Z过程检验非对易时空标度

讨论关于在ILC用γγ到Z过程检验非对易时空能标(原文发在hep-ph/0604115). 在通常时空量子场论中, 由杨氏定理可知一个自旋为1的粒子不可能衰变为两个光子. 但在非对易时空中此过程是允许的. 因此这个过程能作为检验非对易时空的工具. ILC的光子对撞模式能实现这个过程. 如果总亮度能达到500fb^－1, 我们证明对Gamma (Z to gamma gamma)宽度的测量精度将比现有限制(<5.2×10^－5GeV)好3—4个数量级. 对非对易时空能标的检测可高达几个TeV.     

再论生产函数的统计学问题——与余斌、程立茹先生商榷

生产函数有着相应的经济理论背景,是以科学的数据为样本,反复拟合、检验、修正后得到的,揭示产出量与生产要素资本和劳动之间内在的必然的统计相关关系,是科学的结论。本文就此与余斌、程立茹先生进行探讨和商榷。     

Kerr介质中级联三能级原子与压缩相干态相互作用的光子统计演化

本文研究了存在Kerr介质的高Q腔中压缩相干态与级联三能级原子相互作用的光子统计演化规律,讨论了光场参数、Kerr介质及相干振幅对平均光子数的影响.     

Minimum concave cost production system: A further generalization of multi-echelon model

We will consider a concave minimization problem associated with a series production system in which raw material is processed inm consecutive facilities. The products at some facility are either sent to the next facility or stocked in the warehouse. The amount of demand for the final products during periodi, i = 1,,n, are known in advance. Our problem is to minimize the sum of processing, holding and backlogging cost, all of which are assumed to be concave.The origin of this model is the classical economic lot size problem of Wagner and Whitin and was extensively studied by Zangwill. This model is very important from the theoretical as well as practical point of view and this is one of the very rare instances in which polynomial time algorithm has been constructed for concave minimization problems.The purpose of this paper is to extend the model further to the situation in which time lag is associated with processing at each facility. We will propose an efficient O(n ⁴ m) algorithm for this class of problems.     

CoOx改性TiO2光催化剂的制备、优化及其光催化分解水析氢性能研究

利用热分解法制备了不同掺杂量的CoO_x-TiO₂系列光催化剂, 并优化了制备方法。在用XRD、TEM和XPS等技术对催化剂表征的基础上，探讨了乙醇作为电子给体时CoO_x改性对P25-TiO₂光催化分解水析氢性能的影响。本文还利用连续瞬态电流-时间响应和循环伏安法等电化学方法，考察了CoO_x-TiO₂改性系列光催化剂光照条件下电流响应强度、起始光电响应特性差别及光催化析氢电位变化等光电化学性能。光催化性能实验结果表明，适当掺杂CoO_x(110～400 ℃焙烧时最佳掺杂量约为0.4wt% Co，500 ℃焙烧时最佳掺杂量约为0.6～0.8wt% Co)能够显著地提高TiO₂析氢光催化性能，产氢速率提高2个数量级。另外在适当温度下的热处理，能够改善催化剂光催化性能(最佳处理温度为300～400 ℃)。光电化学性能评价结果表明，适当掺杂CoO_x和适当温度下焙烧能在催化剂表面形成较多的析氢活性物种——含钴复合物，能有效增强催化剂光电流响应强度，并使得析氢光还原电位向有利于析氢方向位移。高含量掺杂CoO_x会在催化剂表面形成某种碳化物物种，大量含钴复合物活性中心的出现会降低光吸收效率，增加TiO₂表面光生电子-空穴复合率而使催化剂失去析氢光催化性能。     

Fe-Ni-B-O纳米合金的合成及其催化制氢性能的研究

Preparation and catalytic performance of Fe-Ni-B-O nano-alloy having crystal-palpus structure has been studied. Black powder was synthesized by reducing mixture solution of Fe²⁺, Ni²⁺ with KBH₄ as reducing agent and polyethylene glycol as dispersant. Fe-Ni-B-O nano-alloy of crystal-palpus structure was obtained after hydrogen reduction of black powder. TEM shows that crystal-palpus length is 200～400 nm, diameter is 2～4 nm. The analytic results indicate that the total content of Fe and Ni is 86.6%, B is 5.08%. The alloy exhibits excellent catalytic performance. Hydrogen generation rate can approach 100% especially when pH is 8.