关于U－循环环和双循环环

设Ｒ是有单位元的环．我们称Ｒ为循环环，如果加群（Ｒ，＋）是循环群；称Ｒ为Ｕ－循环群，如果Ｒ的全体单位作成的乘群Ｕ（Ｒ）是循环群；称Ｒ为双循环环，如果（Ｒ，＋）和Ｕ（Ｒ）都是循环群．本文利用（Ｒ，＋）与Ｕ（Ｒ）的一些性质讨论环Ｒ的性质和结构，所得主要结果如下：（１）若Ｒ是Ａｒｔｉｎ半单环，则Ｕ（Ｒ）是有限的当且仅当Ｒ是有限的．（２）域Ｆ是Ｕ－循环环当且仅当Ｆ是有限的．（３）若Ｒ是域Ｆ上所有ｎ阶上三角形矩阵作成的环，则Ｒ是Ｕ－循环环当且仅当ｎ＝２和Ｆ≌Ｚ２．（４）若Ｒ是无限环，则Ｒ是双循环环当且仅当Ｒ≌Ｚ．（５）设Ｒ是有限环且｜Ｒ｜＝ｎ＞１，则Ｒ是双循环环当且仅当Ｒ≌Ｚｎ，ｎ为２，４，ｐｋ，２ｐｋ，其中ｐ为任意奇素数，ｋ为任意正整数．

双循环线性滚环扩增检测HBV替诺福韦耐药位点的方法学研究

目的探讨双循环线性滚环扩增(rolling circle amplification,RCA)检测HBV替诺福韦耐药基因突变位点的可行性。方法以HBV替诺福韦耐药基因突变位点为检测靶点,设计该位点的锁式探针以及包括该位点的HBV野生型、突变性模板。锁式探针与野生型模板特异识别并结合,通过E.coli连接酶连接为闭合环形结构,加入引物启动第1轮RCA;扩增产物用HpaⅠ酶切游离出检测模板,重复上述过程进行第2轮RCA,琼脂糖凝胶电泳检测扩增产物;并对该方法的特异性、检测限及连接效率的影响因素进行初步探讨。结果探针与模板的杂交温度为45℃时,探针的环化连接效率最高、特异性最好。通过对不同浓度野生型模板的检测,单循环RCA的检测限为50pmol/L,双循环RCA的检测限为5pmol/L,检测灵敏度提高了10倍。结论初步建立了检测HBV替诺福韦基因耐药位点突变的双循环RCA方法。

关于I-循环环与I-对合环的结构

采用加群Z(R)与单位群I(R)的性质与结构讨论了I-循环环与I-对合环的结构,对他们的特性进行了分析,并给出了它们之间的相互关系定理,从而深刻地刻划了这两种环.

Comparison of Single Loop and Dual Loop PP Reactors and PP Product Development

The present status of PP technology in China is presented. Through a review of single loop and dual loop PP reactor technology as well as development and utilization of PP products it is concluded that import of PP technology should be based on the demand of PP products and market trend with consideration of local conditions. The existing problems and future development of PP technology in China are discussed.

BIFURCATION OF LIMIT CYCLES FROM A DOUBLE HOMOCLINIC LOOP WITH A ROUGH SADDLE

This paper concerns with the bifurcation of limit cycles from a double homoclinic loop under multiple parameter perturbations for general planar systems. The existence conditions of 4 homoclinic bifurcation curves and small and large limit cycles are especially investigated.

A Fault-tolerant Routing Control for Double Loop Networks

This paper divides the vertex set into several disjoined subsets and provides an optimal fault-tolerance routing algorithm based on the vertex set partition. This algorithm is efficient and convergent, in polynomial time, we can get the output if the vertex is given.

Pneumatic Jet-control Valve for Dual Circulating Fluidized Beds

With the rapid development of circulating fluidized bed(CFB)technology in different fields,the disadvantages of conventional non-mechanical valves are becoming more apparent,and they are not suitable to be used in complex CFB systems.In this paper,a novel non-mechanical valve named the jet-control valve is presented which can avoid the fluidization of solid particles.The feasibility and performance characteristics of the new valve are investigated with a cold-model dual CFB.The results show that compared with the conventional non-mechanical valve,the jet-control valve can transfer solid particles steadily over a larger range,prevent artesian flow,and improve the leakage characteristics.The effects of the operating parameters and structural parameters on the minimum aeration velocity,solid flow rate,and maximum solid flow rate are studied.A two-valve model is proposed to explain the transport capacity of the valve for one jet pipe.A semi-theoretical expression is obtained based on the experimental data with a maximum deviation of 30%providing useful guide for scaling-up the design.