The Effect of the Chain Length on MMA Free Radicl Polymerization

It has been known that the propagation rate coefficient (kp) will change with monomer conversion, Friss, Hamielec et al.1-5 have proposed many formulas about kp to fit this change. In order to obtain the relation between Arrhenius parameters and monomer conversion, a group of kp values at the same monomer conversion must be measured. We adopted a new method through analysis of kp values measured by usual experimental techniques for this purpose. Firstly, we chose a value of monomer convers…     

Métriques de révolution d'un disque et invariance par rotation de la longueur des géodésiques

We give a geometrical proof of a Muhometov type inequality, for a single Riemannian metric defined on a closed disc in the plane. We mainly study the case of equality which is achieved if and only if the distance between points on the boundary is invariant under rotation along the boundary. We show that this implies that the metric itself must be invariant under rotation, at least when the metric is analytic or of nonpositive curvature.     

12种蔬菜作物对铅,铜,镉抗性的研究

通过对12种常见蔬菜作物幼苗在Hoagland营养液中进行水培处理,对其在3种重金属(Pb2 ,Cu2 ,Cd2 )胁迫下的抗性进行了比较研究.结果表明:在12.00 mg/L Pb2 胁迫下,抗性最强的为苋菜,抗性最弱的为大白菜或小白菜;在0.50 mg/L Cu2 胁迫下,抗性最强的为空心菜,抗性最弱的为小白菜;在1.00 mg/L Cd2 胁迫下,抗性最强的为空心菜,抗性最弱的为大白菜.     

On the Helly Number for Line Transversals to Parallel Triangles

We prove two results about the problem of finding the Helly number for line transversals to a family of parallel triangles in the plane: (1) If each three triangles of a family of parallel right triangles are intersected by an ascending (or a descending) line, then there is an ascending (or a descending) line that intersects all     

Application of the Singularity-Separating Method to American Exotic Option Pricing

This paper is devoted to numerical methods for American barrier and lookback options, which are important examples of American exotic options. Since the singularity-separating method is adopted, accurate numerical results can be obtained very fast.     

早期复极综合征与锌的关系：附20例分析

分析了２０例早期复极综合征患者血锌，发现比正常值偏低。早期复极综合征可能与植物神经功能系统的微量元素平衡障碍有关。     

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．     

蒽酮高分子复合物发光体的光老化研究

通过５５５ｎｍ单色光照射下的２小时人工老化和露天中２６个月自然老化。研究了蒽酮高分子复合物发光体的光老化性质，经过２６个月的自然老化发光峰值强度下降了４８％，树脂的光透过度下降了４０％，表明光老化的原因主要是树脂老化引起的。