Delays caused by motorized vehicles unable to clear intersections in China： Graphical analysis

In many Chinese cities,motorized vehicles （M-vehicles） move slowly at intersections due to the interference of a large number of non-motorized vehicles （NM-vehicles）.The slow movement makes a part of M-vehicles fail to leave intersections timely after the traffic signal tums red,and thereby conflicts between vehicles from two directions occur.The phenomenon was analyzed graphically by using the cumulative vehicle curve.Delays in three cases were modeled and compared：NM-vehicle priorities and M-vehicle priorities with all-red intervals unable to release all vehicles,and longer all-red intervals ensuring release all vehicles.Marginal delays caused by two illegal behaviors that occasionally happened in mixed traffic intersections were also investigated.It is concluded that increasing the speed of M-vehicles leaving intersections and postponing the entering of NM-vehicles are the keys in mathematics,although they are uneasy in disordered mixed traffic intersections due to a dilemma between efficiency and orders in reality.The results could provide implications for the traffic management in the cities maintaining a large number of M-and NM-vehicles.     

一类高阶非线性时滞系统的周期解

研究了一类高阶非线性时滞系统的周期解问题，利用不动点定理给出了系统存在唯一一个周期解的几个充分条件及周期解所在的范围，推广和加强了文献［１］的结果。     

判定乳化剂乳化类型的方法研究

介绍一种判定乳化类型的新方法－－体积平衡（VB）值法。VB值是乳化剂的亲水基与亲油基体积比。VB值来源于原子结构的基本常数－鲍林半径,并且可用公式表达、定性分析及定量计算。试验结果表明,VB值大于1即为水包油型乳化剂,VB值小于1则为油包水型乳化剂,VB值具有加和性。     

硫化机群的集散控制系统应用

叙述了两种取代轮胎硫化机三针记录仪的控制方案及对硫化机群进行集散控制的具体方法。     

硬质聚氨酯泡沫在城市集中供热管道上的应用

介绍了城市集中供热管道用硬质聚氨酯泡沫的笥能和组合原料的工艺参数,并对保温管道的3种生产工艺如手工浇注法,一步法连续生产及二步法生产工艺进行了介绍了比较,给出了直埋供热管道保温层厚度的理论计算公式。     

煤基活性炭制备工艺及表面性质的研究进展

煤是制备活性炭或活性炭复合物的重要原料。综述了活化条件和原料组成对煤基活炭的孔结构和表面性质的影响,并对煤基活性炭的研究发展方向进行了展望。     

功能性表面活性剂开发现状及发展趋势

简要论述了功能性表面活性剂在新产品、新材料、新能源的开发生产中的广泛应用,功能性表面活性剂的研究开发现状及发展趋势。     

γ-氯丙基三乙氧基硅烷的合成研制

用三氯氢硅和氯丙烯在氯铂酸催化下合成的γ -氯丙基三氯硅烷 (γ1 ) ,再与无水乙醇反应制得γ -氯丙基三乙氧基硅烷 (γ2 ) ,收率达 90 %以上 ;它可做为各种卤代橡胶的偶联剂 ,也是制备其他硅烷偶联剂的重要原料。     

环Zn上椭圆曲线的群法则及其在Paillier系统中的应用

本文研究了定义在环Zn上椭圆曲线E的有理点集E(Zn)的群的定义法则,以及这类椭圆曲线在密码学上的应用.我们给出了环Zn上椭圆曲线明确的点加公式,使得E(Zn)形成一个交换群,从理论上清晰地解决了以往在该类曲线上某些点相加不能定义的问题.为了在密码学上方便地应用这类椭圆曲线,还给出了在该加法法则下的E(Zn)的群结构....     

Preparation of acrylic/acrylate copolymeric surfactants by emulsion polymerization used in pesticide oil‐in‐water emulsions

In this work, acrylic/acrylate copolymeric surfactants, which can be used in the preparation of pesticide oil‐in‐water emulsions (EW), were synthesized by emulsion polymerization, using potassium persulfate (K₂S₂O₈) as an initiator, dodecyl mercaptan (DDM) as a chain transfer agent at the temperature range of 82–85°C. When the weight ratio of monomers was m(butyl acrylate) : m(methyl methacrylate) : m(acrylic acid) = 4 : 4 : 1.6 and the dosage of DDM was 2% (percentage of monomer mass), the prepared acrylic/acrylate copolymeric surfactants had a number‐average molecular weight of 2.5 × 10⁴ and exhibited good stability for pesticide EW. The carboxylic group distribution studies show that only the surface carboxylic groups make dispersed pesticide oil droplets more stable. The acrylic/acrylate copolymeric surfactants prepared by shot‐monomer had the most surface carboxylic group distribution (46.6%). To obtain greater surface carboxylic group distribution, maleic anhydride (MA) was used to modify the polymer system. Adding 2% MA (percentage of monomer mass) to the polymerization system, the surface carboxylic groups were increased 12% over unmodified acrylic/acrylate copolymeric surfactants. Compared with traditional pesticide EW, the avermectin EW prepared with acrylic/acrylate polymeric surfactant had much better stability. Meanwhile, its pesticide effect was similar to that of a control (1.8% abamectin emulsifiable solution). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012