电子碰撞诱导原子从低激态向高激态弛豫

本文根据空心阴极放电中电子能量分布的物理图象,分析了原子从低激态向高激态弛豫的可能途径。建立高低激态集居数密度增量的关系。讨论高激态集居数密度增量获得可观量的条件。根据此条件分别选取钠原子的基态3s~2S_(1/2)和铜原子的亚稳态4s~2D_(3/2)为与激光共振的下能级,并激发具有较大自发发射几率的3s~2S_(1/2)→3p~2P°_(1/2)(和3p~2P°_(3/2))和4s~2D_(3/2)→4p~2P°_(1/2)跃迁,在远离上能级的高激态上观测到敏化荧光,并精确测得这些态的自发发射系数比值,而在更高激态上没有观测到敏化荧光,表明讨论中提出的条件是合理的。     

红外光谱法研究含CeSt3的LDPE膜紫外光氧降解

报道了硬脂酸铈（ＣｅＳｔ_３）、及其在各种浓度、或不同温度、或延长贮放时间下含ＣｅＳｔ_３的低密度聚乙烯（ＬＤＰＥ）膜紫外光氧化降解过程的红外光谱。结果表明，只要在ＬＤＰＥ膜中加入０．１ｗｔ＋％～０．３ｗｔ＋％ＣｅＳｔ_３光敏剂，即可控光降解ＬＤＰＥ膜的寿命。     

The effect of UV light on the thermooxidative stability of linear low density polyethylene films crosslinked by ionizing radiation

The effect of ultraviolet (UV) light on the thermooxidative stability of Linear Low Density Polyethylene(LLDPE) films was studied. LLDPE was stabilized with phenolic type antioxidant known as Irganox 1010, hindered amine light stabilizer known as Chimmasorb 944 and phenolic type gamma stabilizer. The influence of these additives on the thermooxidative stability of gamma and UV irradiated LLDPE were investigated by isothermal Differential Scanning Calorimeter (DSC). The oxidation induction time (OIT) experiments indicate that antirad free LLDPE films which contains antioxidant and UV stabilizer are more sensitive to gamma and UV radiation. On the other hand, films which contain antirad and irradiated to different doses of γ-radiation demonstrated improved thermooxidative stability.     

Convergence of interval-type algorithms for generalized fractional programming

The purpose of this paper is to analyze the convergence of interval-type algorithms for solving the generalized fractional program. They are characterized by an interval [LB _k , UB _k ] including*, and the length of the interval is reduced at each iteration. A closer analysis of the bounds LB _k and UB _k allows to modify slightly the best known interval-type algorithm NEWMODM accordingly to prove its convergence and derive convergence rates similar to those for a Dinkelbach-type algorithm MAXMODM under the same conditions. Numerical results in the linear case indicate that the modifications to get convergence results are not obtained at the expense of the numerical efficiency since the modified version BFII is as efficient as NEWMODM and more efficient than MAXMODM.This research was supported by NSERC (Grant A8312) and FCAR (Grant 0899).     

大鼠肾组织的超低温快速冷冻固定和冷冻置换研究

超低温快速冷冻固定以极高的冷冻速率（１００００Ｋ／ｓ）对生物组织进行物理固定，可使生物组织结构、组织内可溶性离子及游离性物质得到保存，使被固定后的生物组织保持最接近于原自然状态，这种样品制备方法大大优于化学制备法，因而在Ｘ－射线微分析及免疫细胞化学中得到广泛应用。生物样品超低温快速冷冻后，利用冷冻置换法，在低温下将生物组织内的结晶水缓慢置换出来，而后常规包埋切片，可获得理想的组织结构及组织内待分析成分。本文应用超低温快速冷冻固定技术及冷冻置换法对大鼠肾皮质部的快速冷冻固定及损伤进行探讨。     

双功能催化剂体系作用下乙烯二聚和共聚合的研究

用乙烯为原料在双功能催化剂体系的作用下通过二聚和共聚合反应，直接合成线性低密度聚乙烯（ＬＬＤＰＥ）．所用二聚反应催化剂为钛酸正丁酯（Ｔｉ（ＯＢｕ）_４），共聚催化剂为ＴｉＣｌ_４／ＭｇＣｌ_２（ＺＭ－１催化剂）．研究了二聚反应动力学行为及影响双功能催化剂体系动力学过程的一些因素．结果表明利用这两种催化剂组成双功能催化剂体系能够很方便地制得密度范围在０．９０－０．９３，Ｅｔ／１０００Ｃ在１０－４０的ＬＬＤＰＥ．     

K~+-FREE INDUCED EARLY AFTERDEPOL-ARIZATION IN CARDIAC VENTRICULAR FIBERS OF GUINEA PIG AFTER COLD TREATMENT

The genesis and elimination of early afterdepolarizations (EADs) have been investigated in guinea pig cardiac ventricular fibers after a short period of cooling (5h, 2—4℃). After rewarming them to 37℃, EADs could be induced by K~+-free superfusion at an appropriate driving stimulation (0.2 Hz) in all preparations. A high level plateau, which linearly increases its duration with time, appears ahead of EADs. The critical point of the plateau occurred steadily at the level of -47±4 mV. Two types of triggered activity, all of which are the rhythmic activities in low level of membrane potential (-50 to -60 mV), appear on the platcau. There is no significant change after overdriving. Agonists of the Na-K pump (K~+ and Tl~+) could stop the rhythmic activity immediately and turn the low level of membrane potential to high one. The results showed that high level plateau is the basis of genesis of EADs, and the activation of Na-K pump plays an important part in stopping triggered rhythms arising from EADs.     

单分散纳米InVO4(正交相)的低温合成

InVO₄ is a new developed visible light responding photocatalyst for water decomposition, which is obtained by a solid-state reaction at high temperature traditionally. In this paper, pure InVO₄ nano-crystalline powder has been prepared by a hydrothermal process at low temperature and was characterized by TEM, IR, and X-ray diffraction. Many factors such as pH value, reaction time and temperature have been investigated. It is found that the optimal conditions for the preparation is: n_InCl3∶n_NaVO3=1∶2; temperature : 150 ℃; Reaction time: 4～8 h; pH=7.9～8.0. And the experimental result shows that it is a convenient way to get single dispersing InVO₄ nano-crystalline powder by flux in alkyl alcohol.     

Investigation of glow discharge plasma for surface modification of polypropylene

Material surface properties of polymers, plastics, ceramics and textiles can be modified by atmospheric or low‐pressure glow discharge plasma. The aim of the present work is to study the surface modification of biaxially oriented polypropylene (BOPP) film in order to improve its hydrophilic and wetting properties. In this article we used low‐pressure, low‐temperature oxygen plasma for the surface treatment of BOPP. Scanning electron microscopy indicates that plasma treatment causes mainly physical changes by creating microcraters and roughness on the surface and increasing surface friction. Attenuated total reflectance infrared spectra show oxygen‐containing groups such as ? OH at 3513 cm^?1 and C?O at 1695 cm^?1. Microscopic investigations of water droplets on BOPP (treated, untreated) show that the interfacial adhesion of treated surfaces is increased. Copyright © 2003 John Wiley & Sons, Ltd.