SOLUTIONS TO TEXT PROBLEMS 13.1 The field strength of an NMR spectrometer magnet and the frequency of electromagnetic radia he Ire tion used to observe an NMR spectrum are directly proportional. Thus, the ratio 4.7 T/200 MHz is the same as 1.41/60 MHz. The magnetic field strength of a 60-MHz NMR spectrometer is

Chlorotoluene Benzyl chloride Of this group only benzyl chloride is not an aryl halide; its halogen is not attached to the aromatic ring but to an sp-hybridized carbon. Benzyl chloride has the weakest carbon-halogen bond, its measured carbon-chlorine bond dissociation energy being only 293 kJ/mol (70 kcal/mol). Homolytic cleavage of this bond produces a resonance-stabilized benzyl radical

9-3实系数多项式根的分布 9.3.1复系数多项式的根的绝对值的上界 命题设f(x)=axn+a1xn+…+an∈C[x],其中a≠0而n≥1。令 a=max{ 则对f(x)的任一复根a,有|ak1+A/a 证明如果A=0,则a=0,命题成立。下面设A>0 如果|a1+A/a,那么,因为f(a)=0,故有 la Haa++aa a+…+an ≤A(ar-++1)=a(la--1)/(a-1) 现在|a>1,故从上式立刻得到 la a\ Ala\ /(al-1) 两边消去|a,得|ak1+A/a|,矛盾

Dyspnea is defined as an awareness of difficulty in breathing It is therefore a symptom, usually described by the patient as \shortness of breath,\whether the sensation is due to actual difficulty in breathing or is essentially an awareness of hyperventilation. If the symptom becomes striking, it always companies with dilatation of nares, cyanosis, use of accessory muscles of respiration and abnormalities of respiratory rate, depth or rhythm

Coughing is an essential defense mechanism that it prevents the airways from the foreign substance and clear the excretion of respiratory tract. Coughing is a reflex. permanent and frequent coughing indicates an abnormality

9.2.2Qx]内多项式的因式分解 定义9.12定义Z[x]={axn+a1x+…+∈Z,i=01n}。 假设f(x)∈Z[x],f(x)≠0及±1。如果g(x)h(x)∈[x],使得f(x)=g(x)h(x), 且g(x)≠±1,h(x)≠±1,则称f(x)在Z[x]内可约,否则称f(x)在Z[x]内不可约 定义9.13设 f(x)=ax+axn+…+an∈Z[x], 这里n≥1。如果(aa1an)=1,则称f(x)是一个本原多项式。 命题Q[x]内一个非零多项式f(x)可以表成一个有理数k和一个本原多项式f(x)的

Definition: Dyspnea is defined as an awareness of difficulty in breathing It is therefore a symptom, usually described by the patient as \short of breath,\ whether the sensation is due to actual difficulty in breathing or is essentially an awareness of hyperventilation. If the symptom becomes striking, it always companies with dilatation of nares, cyanosis, use of accessory muscles of respiration and abnormalities of respiratory rate, depth or rhythm

Interactions within a package system refer to the exchange of mass and energy between the packaged food, the packaging material and the external environment. Food-packaging interactions can be defined as an interplay between food, packaging, and the environment, which produces an effect on the food, and/or package (Hotchkiss, 1997). Mass transfer processes in packaging systems are normally referred to as permeation, migration and absorption(fig8.1). Permeation is the process resulting from two basic mechanisms

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

Product development does not occur in isolation as a separate functional activity. It is a company philosophy, a basic company strategy and a multifunctional company activity. In recent years to show this all-encompassing basis, bringing together product, process, marketing and organisational innovations, there has been development of an overall innovation strategy. This innovation strategy is related to the company's overall business aims and strategy, as well as the social, economic and technological environment, and the company's own knowledge and skills. The business strategy also includes a duct strategy outlining the products of the future. The combination of the innovation and product strategies is the basis for the product development strategy, and from this can be developed