不同岩蔷薇浸膏挥发性致香成分的SED-GC-MS分析研究

岩蔷薇(cistusladaniferusL.)又名赖百当(labdanum),属半日花科。利用其树脂分泌物及枝叶,通过蒸馏、浸提和萃取等方法,可制得岩蔷薇精油、浸膏、净油、油树脂等各种香原料品种。岩蔷薇的香原料制品是膏香类的极重要品种,主要应用于日化和食品行业,在烟草行业也多有应用。因香料烟香味的主要来源是类赖百当化合物的降解,故被归为烟草的五大类香味物质之一:赖百当类、双萜烯及其降解产物类。这类物质在香料烟中的含量较高,对形成香料烟的特殊香味风格具有重要意义,且在烟草中赖百当仅存在于香料烟中,烤烟、自肋烟中均不存在。赖百当类化合物是香料烟中特有的香气物质,主要成分是冷杉醇、赖百当烯二醇,经调制和醇化转化为多种降赖百当类化合物,其中降龙涎香醚、龙涎香内酯、脱氢龙涎香内酯等都具有强烈的龙涎香香气,对增进卷烟香气和吃味有很好作用。     

On relative stability of linear stationary feedback control systems with time delay

A method is presented whereby the absolute and relative stabilityof linear control systems containing transport lag can be determined.As a result feedback systems with variable time delay and loopgain, may be investigated in straightforward manner.     

Local solutions to high-frequency 2D scattering problems

We consider the solution of high-frequency scattering problems in two dimensions, modeled by an integral equation on the boundary of a smooth scattering object. We devise a numerical method to obtain solutions on only parts of the boundary with little computational effort. The method incorporates asymptotic properties of the solution and can therefore attain particularly good results for high frequencies. We show that the integral equation in this approach reduces to an ordinary differential equation.     

Modelling and control of natural convection in canned foods

In this paper we study mathematically an industrial problemrelated to sterilization processes involving heat transfer bynatural convection. We give results of existence and regularityfor the solution of this problem. We recast the whole problemas an optimal control problem with pointwise constraints onthe state and the control in order to ensure the reduction ofmicroorganism concentration and the retention of nutrients,and to save energy. Finally, we give results on existence ofthe optimal solution and optimality conditions for its characterization.     

Majority voting leads to unanimity

We consider a situation where society decides, through majority voting in a secret ballot, between the alternatives of ‘reform’ and ‘status quo’. Reform is assumed to create a minority of winners, while being efficient in the Kaldor–Hicks sense. We explore the consequences of allowing binding transfers between voters conditional on the chosen alternative. In particular, we establish conditions under which the winners wish to compensate all losers, thus leading to unanimity for reform, rather than compensating some losers to form a non-maximal majority. The analysis employs concepts from cooperative game theory.      

On some nonself mappings

Let X be a Banach space, let K be a non–empty closed subset of X and let T : K → X be a non–self mapping. The main result of this paper is that if T satisfies the contractive–type condition (1.1) below and maps ?K (?K the boundary of K) into K then T has a unique fixed point in K.