查询词典 atom

Multicomponent reactions have been widely studied because very high atom economy is achieved in the synthesis of complex molecules.

多元反应已被广泛研究，因为原子经济建设取得很高的复杂分子的合成。

The absorption maxima and emission maxima didnt change obviously between the five-membered compounds when N-methyl as the bridge atom. The value of extinction coefficient was increased obviusly compared naphthalimide with naphthalic anhydride.

甲基化氮为桥原子的五元化合物之间最大吸收和发射波长相差不大，萘酰亚胺的消光系数比萘酐增加明显，loge最大相差可达0.45，荧光强度也略有增加，相差0.1左右。

In the same time, the intra-molecular photoinduced electron transfer process between naphthyl group and nitrogen atom of tertiary amine group at the tip of molecule was found and this process strongly depends on the acidity of solution.

通过对该类化合物在溶液中的光物理行为以及酸度影响的比较研究，观察到以叔胺为骨架的三足化合物存在分子内光诱导电子转移，且这一过程强烈地依赖于介质的pH值；叔胺基的氮原子质子化将会减弱这一PET过程。

In the depth surpasses in 10 meter deep well nitrogenation oven technique of manufacture, applied the multi-link graduation to enter the ammonia active nitrogen atom weaken compensation method, caused the nitrided uniformity distinct enhancement.

在深度超过10米的深井氮化炉制造技术中，应用了多环分级进氨气活性氮原子衰减补偿法，使氮化均匀性明显提高。

How can we solve this problem? First, we must find a way to let the oxygen activated; secondly, let the H atom cleavage from the methyl, and turn to carbanions; finally, the activated dioxygen react with carbanions, so the problem of oxidizate nitrotoluene is sloved in the end.

因此，在较温和的条件下高选择性氧化硝基甲苯制备硝基苯甲酸是一个具有重要理论意义和实用价值的研究课题。

Can induce the reaction of cleavage H atom from methyl on the ring of deactivated toluenes,such as nitrotoluene. The carbanions caused by base are the very important reaction intermediums, which determined the reaction rate and reaction effect.

该反应体系中，NaOH的加入对此催化反应起着相当关键的作用，研究表明强碱也能像温度一样促进苯环卜甲基的摘氢速度，使底物形成相应的硝基苯甲基阴离子，稳定的硝基苯甲基阴离子是氧化反应进行的重要中间体。

The two major categories are aliphatic, with the carbon atom s in straight or branched chains or in nonaromatic rings, and aromatic

烃主要的两种类型是脂肪类和芳香类。。脂肪烃中的碳原子排成直线或分支的链，或者结成非芳香族的环。

Only when the outer electrons forming dangling bonds absorb noncontiguous specific energy and transit into relative free status, can they bond with each other, that is, only when C atom in 3DB status takes in enough energy and conquers potential barrier can it realize reconstruction.

构成悬挂键的外层电子只有吸收非连续的特定能量跃迁成相对自由状态才可能彼此成键，即处于3DB状态的C原子吸收足够能量克服势垒才能实现重构。

Wear model and characteristics of the second cutting deformation zone,that is,between the rake face of cutter and chips were investigated by carrying out diamond PCD cutter ultraprecision machining test of SiC noncontinuous reinforced aluminum composites,and measuring analysis with atom force microscope and scan electronic microscope.

通过金刚石PCD刀具对非连续S iC增强铝基复合材料的超精密车削加工试验，考察了刀具第二切削变形区的摩擦磨损性能，并提出了相应的模型；采用爆炸式快速落刀装置制备出切屑根并分析了积屑瘤的影响因素；采用原子力显微镜对PCD刀具的刃口磨损形貌进行观察，并分析其磨损机理。

A scheme is presented to generate the entangled squeezed coherent states via the nonresonant interaction of a two-level atom with a two-mode cavity field.

提出一种利用一个二能级原子与一两模腔场的非共振相互作用制备纠缠压缩相干态的方案。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。