The packaging sector is an important global industry, representing about 2% of the Gross National Product (GNP) of the developed countries. The value of the packaging industry is about 345 million euros worldwide, of which Europe represents a third. Fifty per cent of this market is packaging for food. Forecasts suggest that the sector will continue to grow in size and importance Many cooking and preservation processes still largely depend on effective packaging, for example canning, aseptic, sous vide and baking processes. Processes such as drying and freezing would be lost without protective packaging after processing to control product exposure to the effects of oxygen light, water vapour, bacterial and other contaminants. However, modern food packaging no longer has just a passive role in protecting and marketing the product. It increasingly has an active role in processing, preservation

SOLUTIONS TO TEXT PROBLEMS 6.1 Catalytic hydrogenation converts an alkene to an alkane having the same carbon skeleton. Since 2-methylbutane is the product of hydrogenation, all three alkenes must have a four-carbon chain with a one-carbon branch. The three alkenes are therefore:

itrogen-containing compounds are essential to life. Their ultimate source is atmo- spheric nitrogen which, by a process known as nitroge. nitrogen fixation, is reduce ced to ammonia, then converted to organic nitrogen compounds. This chapter describes the chemistry of amines, organic derivatives of ammonia. Alkylamines have their nitro- gen attached to sp'-hybridized carbon; arylamines have their nitrogen attached to an sp2-hybridized carbon of a benzene or benzene-like ring

SOLUTIONS TO TEXT PROBLEMS 8.1 Identify the nucleophilic anion in each reactant. The nucleophilic anion replaces bromine as a sub- stituent on carbon. (b) Potassium ethoxide serves as a source of the nucleophilic anion CH,CH,. CH,CH,: CH, Br: CH3CH2OCH3 + Br: Ethoxide ion Methyl bromide Ethyl methyl ether Bromide ion

一、最佳选择题:在五个备选项中选择一个最合适的选项,并将相应序号A、B、C、D或E填入答题纸上;每题2分,共20分。 1.思想道德修养课程的教学目的主要在于解决()问题 A.世界观、人生观和价值观 B.目标意识和理想观 C.金钱观、苦乐观和幸福观 D.成才观和人生价值观 E.爱情观和友谊观

一、单项选择题(本大题共10小题,每小题2分,共20分) 在每小题列出的四个备选项中只有一个是符合题目要求的,请将其代码填写在题后的括 号内。错选、多选或未选均无分。 1.对任意n阶方阵A、B总有() A.AB-BA

1 The physical construction of three pairs of coupled coils is shown in Fig. 10-16. Show two different possible locations for the two dots on each pair of coils. 2 For the circuit illustrated in Fig. 10-17 (a) find I and VB; (b) repeat if a 62 resistor is connected between the terminals at the right

一、单项选择题 1、操作系统是一种(B)。 A.应用软件B.系统软件C.通用软件D.工具软件 2、操作系统是一组(C)。 A.文件管理程序B.中断处理程序 C.资源管理程序D.设备管理程序

The Normal Distribution: the distribution of a continuous r.v. whose value depends on a number of factors, yet no single factor dominates the other. 1. Properties of the normal distribution: 1)The normal distribution curve is symmetrical around its mean valueu. 2)The PDF of the distribution is the highest at its mean value but tails off at its extremities

1-1截面为16a号槽钢的简支梁,跨长1=4.2m,受集度为q=2kN/m的均布荷载作 用,梁放在=20°的斜面上。试确定梁危险截面上A点和B点处的弯曲正应力