A molecule of water consists of two atoms of hydrogen and one atom of oxygen

水分子含有两个氢原子和一个氧原子

属类：综合句库--

As the nearly unreactive diatomic molecule N2, it is useful as an inert atmosphere or to dilute other gases. Nitrogen is commercially produced by distillation of liquefied air. Nitrogen fixation, achieved naturally by soil microbes and industrially by the Haber-Bosch process, converts it to water-soluble compounds (including ammonia and nitrates).

它是最稳定的双原子分子N2,可用来产生惰性的气体氛围,或用于稀释气体。商业上通过液化空气的蒸馏来生产氮气。自然界通过土壤里的微生物可达成固定氮作用,而在工业上则利用哈伯-博施法将它转化成可溶于水的化合物(包括氨和硝酸盐)。

属类：化学及生命科学-化学-

Any of a large group of enzymes that catalyze the hydrolysis of peptide bonds in the interior of a polypeptide chain or protein molecule .

肽链内切酶在多肽链或蛋白分子内部加速肽键水解的任何较大的酶群

属类：综合句库--

In general, any molecule that is attracted to water molecules is said to be hydrophilic (water-loving)

通常,任何被水分子吸引的分子都称为亲水的(喜水的)。

属类：综合句库--

We did work in thermonuclear energy, laser beam refraction, hydrogen molecule development, and heavy-water computer data

我们从事过热核能、激光束折射,氛分子发展和电脑重水数据的研究工作。

属类：综合句库--

At any rate, two oxygen atoms form, saturated and happy, a molecule

无论如何,两个氧原子形成一个饱和的适宜的分子。

属类：综合句库--

Any of a class of monosaccharides having five carbon atoms per molecule and including ribose and several other sugars.

戊糖分子中含有五个炭原子的一种单糖,包括核糖及其它几种单糖

属类：综合句库--

The law of conservation of matter requires that every atom on the left appear on the right (the equation must balance); only their arrangements and combinations change. For example, one oxygen molecule combining with two hydrogen molecules to form two water molecules is written 2H2 + O2 ? 2H2O. The dissociation of salt into sodium and chloride ions is written NaCl ? Na+ + Cl-.

物质的守恒定律要求左侧的每个原子都要出现右侧(方程式必须平衡),只有排列与组合方式改变。例如一个氧分子和两个氢分子结合,形成两个水分子,写成2H2+O2→2H2O。食盐游离成钠和氯离子,写成NaCl→Na++Cl-。

属类：化学及生命科学-化学-

The term usually refers to synthetic substances and excludes soaps. The characteristic features of a molecule of any detergent are a hydrophilic (water-attracting)end and a hydrophobic (oil-attracting)end. In ionic detergents, the hydrophilic property is conferred by the ionized part of the molecule. In nonionic detergents, hydrophilicity is based on the presence of multiple hydroxyl groups or other hydrophilic groups.

洗涤剂也往往用作乳化剂。洗涤剂通常不是指油脂皂化而得的肥皂,而是指一种合成物质。在水中洗涤剂的主要用途是洗杯、碟和衣服。任何一种洗涤剂都具有一个亲水端和一个疏水端。在离子洗涤剂中,亲水性是由分子的离子化部分而来。在非离子洗涤剂中,亲水性是基于多羟群和其它亲水残余物的存在而产生。

属类：化学及生命科学-化学-

In a molecule as complex as benzene a very considerable number of normal vibrational modes are possible

象苯这样复杂的分子,可能存在很多简正震动形式。

属类：综合句库--

The number of components of an antigen molecule to which an antibody molecule can bind.

效价能和抗体分子结合的抗原分子的组成成分的数目

属类：综合句库--

Many biologically important organic compounds (sugars and amino acids)possess at least one asymmetric carbon atom and therefore occur in two isomeric forms for the amino acid molecule .

许多对生物重要的有机化合物(糖和氨基酸)存在着至少一种非对称碳原子,并因此使这个氨基酸分子产生了两个同分异构体。

属类：工程技术-食品工程-

Many have characteristic odours. Oxidation of aldehydes yields acids; reduction produces alcohols. They participate in many chemical reactions and readily undergo polymerization into chains containing tens of thousands of the monomer molecule .

许多醛有特殊的、悦人的气味。它们很容易氧化成酸或还原成醇。醛类也可以发生化学反应或聚合反应,简单的醛可以很容易地连接在一起成为含有数万个分子的链。

属类：化学及生命科学-化学-

The haemoglobin molecule contains only four atoms of iron.

血红蛋白分子只含有四个铁原子。

属类：综合句库--

It is the particular sequence of the nucleotide blocks along the molecule that encodes the genetic information

沿着分子核苷酸的特定序列为遗传信息编码。

属类：综合句库--

Oxygen: Gaseous chemical element, chemical symbol O, atomic number 8. It constitutes 21% (by volume)of air and more than 46% (by weight)of Earth's crust, where it is the most plentiful element. It is a colourless, odourless, tasteless gas, occurring as the diatomic molecule O2.

氧:周期表VIa族非金属化学元素。化学符号O,原子序数8。无色、无臭、无味的气体,为地壳中含量最多的元素,它的最重要的化合物是水。氧在大气中占21%,在地壳中占46.6%。地面和下层大气的氧气,几乎都由双原子分子O2组成。

属类：化学及生命科学-化学-

One molecule may transform several million reactant molecules a minute. Catalysts may be gaseous, liquid, or solid; they may be inorganic compounds, organic compounds, or complex combinations.

一个催化剂分子可在一分钟内转化成好几百万个反应物分子。气态、液态和固态的催化剂可能是无机化合物、有机化合物,或是复杂的化合物。

属类：化学及生命科学-化学-

A molecule whose Stokes' radius approaches or exceeds the pore radius does not enter the gel and is said to be excluded

一个分子,它的Stokes半经接近或超过网眼半经,不进入凝胶内,称为被排阻。

属类：综合句库--

A molecule is a thousand times bigger than an atom of hydrogen.

一个分子比一个氢原子大一千倍。

属类：综合句库--

The absorption of infrared ray by a molecule causes all sorts of subtle changes in the vibrational or rotational energy of the molecule

一个分子能吸收红外光引起分子中振动能量和旋转能量的各种各样的微小变化。

属类：综合句库--

A polymer-forming reaction involving elimination of a small molecule such as water or alcohol between monomer units is described as condensation polymerization.

一个涉及在两个单体单元之间消除一个小分子(例如水或醇)形成聚合物的反应被称为缩聚反应。

属类：化学及生命科学-化学-

A major class of tautomeric reactions involves exchange of a hydrogen atom between two other atoms in the same molecule , in both cases forming a covalent bond. For example, in keto-enol tautomerism, the hydrogen atom bonded to the carbon atom in a carbonyl (keto)group (-CH-C=O; see functional group)moves to the oxygen atom, making it an enol group (-C=C-OH).

一类主要的互变异构反应是氢原子在两个其它原子间交换,与任何一方都生成共价键。例如,在酮基-烯醇基互变异构中,与羰(酮)基(-CH-C=O;参阅functional group)中的碳原子键合的氢原子移到了氧原子上,使它变成了烯醇基(-C=COH)。

属类：化学及生命科学-化学-

A colourless, odourless, tasteless, flammable gas, it occurs as the diatomic molecule H2. Its atom consists of one proton (the nucleus)and one electron; the isotopes deuterium and tritium have an additional one and two nuclear neutrons, respectively.

一种无色、无臭、无味的可燃性气体物质,氢原子很活泼,可以彼此结合成对,形成分子式为H2的双原子氢分子。其原子含有一个质子和一个电子;其同位素氘和氚分别多出一和二个中子。

属类：化学及生命科学-化学-

The small molecule causing the conformational change is an allosteric effector

引起结构变化的小分子叫做变构效应场。

属类：综合句库--

Invented by Kary Mullis, PCR requires a DNA template (as little as one molecule )to copy, nucleotides to build the copies, and the enzyme DNA polymerase to catalyze the formation of bonds between the nucleotide monomers.

由马利斯发明,该反应需要有一用于复制的DNA模板(大小如同一个分子),进入复制品的引物,另外还要有一些DNA聚合来促成核单体团的形成。

属类：化学及生命科学-化学-

Each consists of a molecule of a five-carbon sugar (ribose in RNA, deoxyribose in DNA)and a nitrogen-containing base, either a purine or a pyrimidine.

由一分子五碳糖(核糖核酸中的核糖、去氧核糖核酸中的去氧核糖)与一含氮的嘌呤或嘧啶相连而成。

属类：化学及生命科学-化学-

An active protein molecule has three important levels of structure: primary (the amino acid sequence), determined by the genes; secondary (the geometric shape, often a helix), determined by the angles of the covalent bonds between and within amino acids; and tertiary (the looped and folded overall shape), determined largely by attraction between oppositely charged groups (and repulsion between like charged groups)on amino-acid side chains and especially by hydrogen bonding.

有效的蛋白质具有三层重要结构:一级结构(氨基酸序列)由基因决定;二级结构(几何形状,通常是螺旋)由氨基酸之间或内部共价键的角度来决定;三级结构(环状或折叠的整体形状)由氢键与氨基酸侧链来决定。

属类：化学及生命科学-化学-

Evidence shows these films to be generally one molecule thick, and such surface films are called spread monolayers

有证据表明,这些膜一般都是一分子厚。这样的表面膜叫做分散单分子层。

属类：综合句库--

The larger the number of heteroatoms, the more highly oxidized the molecule

杂原子数越多,分子被氧化的程度越高。

属类：综合句库--

The maximum amount of nitrogen chemisorbed at 450°C, which is about 2.75 mmol/g, corresponds to one molecule for every six framework silicon tetrahedron.

在450℃,氮气的最大化学吸附量大约是2.75mmol/g,相当于每六个框架的硅四面体吸附1分子氮气。

属类：化学及生命科学-化学-