The practice of measuring and keeping records of temperatures is not new to the food industry, and has been undertaken by certain sectors, e.g. canning, for many years. However, its widespread application in the refrigerated food sector, other han fitting temperature measurement equipment to chill stores, is relatively recent. The prime factor focusing attention on temperature monitoring was the concern about food poisoning and the introduction of new legislation covering

1. Two hydrogels are prepared from two different candidate polymers for controlled release of a protein drug, interleukin-2(IL-2). The gels exhibit the same swelling ratio at equilibrium, but gel A(formed by cross-linked polymer A, repeat unit molecular weight Mo= 100 g/mole)has

Problem 1. An undirected graph G has width w if the vertices can be arranged in a se- quence V1,2,3,…,Vn such that each vertex v; is joined by an edge to at most w preceding vertices. (Vertex vj precedes if i.) Use induction to prove that every graph with width at most w is (w+1)-colorable

Restriction enzymes are extensively used in molecular biology. Below are the recognition sites of two of these enzymes, BamHI and Bcll. a)BamHI, cleaves after the first G: 5'GGATCC 3 3 CCTAGG5 Does cleavage by BamHI result in a 5' or 3 overhang? What is the sequence of this overhang?

5.1 自发变化的共同特征 热力学第二定律 5.2 熵 5.3 熵变的计算 5.5 亥姆霍兹自由能和吉布斯自由能 5.4 热力学第三定律与规定熵 5.6 △G的计算示例

1范围 本方法测铍的检出限,直接显色测定为0.001g/l(=0.010),测定上限为0.028mg/L,经 活性炭富集,方法的检出限可达0.0001mgL(取水样量按500mL计) 不经活性炭分离,在测定条件下,可允许0.mg钙(I)镁(),0.3mg钻(Ⅱ)铅()、铝 (I镉(),0.1mg镍(Ⅱ)、铜()、,(V),6mg氯离子,48mg硫酸根存在;用活性炭吸附 分离,可允许20mg镁(I锌(),15mg钻(II)、()铅(),10mg钙(镉m、钼(V) 5mg铁()银(),3mg铜()、铝(I)(,2mg铬(,V)、1mg(),0.5mg钒(V) 及5mg磷酸根,0.05mg氟离子存在

1范围 本方法适用于铀矿冶炼排放废水中微量铀的测定,取水样100mL,方法的最低检出浓度 为0.0013mg/L(在吸光度A=0.01时所对应的铀浓度),测定上限为1.6mg/L(取水样1mL) 按本方法萃取分离和显色测定lig铀时,硫酸根50mg;抗坏血酸160mg;钾、铝、铁 (I氯、高氯酸根、磷酸根各100mg、钙90g;镁50mg;钠40mg;镉30mg、铜(20mg 锰(I),铋、钴、镍、铅、钼(VI)、锌各10mg:汞(I)砷(V、钨(VI)、锡(I)各5mg硅酸根 4mg;()铼(VI)各2mg;锆(V锶钍、银、镧、锂、锑、硒各1mg;亚硝酸根0.7mg

3.1 What is learning? Are they instances of learning? (1) A young child takes his first steps. (2) An adolescent male feels a strong attraction to certain females. (3) A child feels anxious when he sees the doctor coming with a needle. (4) Long after learning how to multiply, a girl realizes on her own that another way to multiply by 5 is to divided by 2 and multiply by 10(e.g. 428×5 can by figured as follows:428/2=214 ×10=2140)

7-3 7-5 a) R2引入电压并联负反馈 b) R3引入电压串联负反馈 c) R3引入正反馈 d) 级间R6引入交流正反馈；第一级R4引入电流串联负 反馈；第二级R7引入电压串联负反馈 e) R7电压并联负反馈 f) R3,R7,R8电流串联负反馈 g) R3,R4电压串联负反馈 h) RF引入电流并联负反馈

1. 写出分子式为 C5H10O 的醛和酮的结构式，并用普通命名法和 IUPAC 命名法命名。 2. 分别指出苯乙醛和苯乙酮与下列试剂反应后的产物 (1)NaBH4 而后 H3O+；(2)Tollens 试剂；(3)C2H5MgBr 而后 H3O+；(4)2CH3OH/HCl（g） (5)NH2OH；(6)HCN/KCN；(7)H2NNH2