查询词典 chemical method

The preparation of Fe3O4 nanoparticle with chemical co-precipitation method, and surface modification by sodium oleate were introduced.

采用共沉淀法制备纳米Fe3O4胶体溶液，并用油酸钠对其进行包覆改性。

Several transient compounds were synthesized by the homo- and heterogeneous reactions of reactive halogen compounds, In-situ ultraviolet photoelectron spectroscopy and photoionization mass spectroscopy as well as theoretical calculations were used to study their molecular structures, stability and molecular orbital properties, their electronic structures and geometric structures were obtained for the first time; Simultaneously, the electronic structure and thermal dissociation of acetyl peroxynitrate and trifluoroacetyl peroxynitrate which have great importance in the atmospheric chemistry were studied; The substituent effects of series of halopyridines and halothiophenes were studied by the ultraviolet photoelectron spectroscopy method for the first time. The atmospheric chemical reaction between peroxyacetyl radicals with IO radicals as well as the dissociation of the most stable isomer of CH3COIO3 were calculated by density functional theory, it was found that the CH3COOIO2 isomer may be act as a new reservoir of inorganic iodine in the stratosphere.

通过活性卤素的系列均相与非均相化学反应合成了几种瞬态物种，采用原位紫外光电子能谱和光电离质谱结合量子化学理论计算对化合物的分子结构、稳定性以及分子轨道特性进行了研究，首次获得了这些物种的电子结构和几何结构的信息；同时研究了大气中有重要作用的乙酰过氧硝酸酯和三氟乙酰过氧硝酸酯的电子结构性质及热解过程；采用紫外光电子能谱手段首次研究了系列卤代吡啶和噻吩的取代基效应；通过量子化学理论计算研究了乙酰基过氧自由基与IO自由基的大气化学反应及其最稳定异构体CH3COOIO2的解离，发现该物种可能是无机碘化合物在平流层中的储库物种。

A method is proposed in order to accelerate the convergence of artifcial neural network modeling of chemical process,in which the principal components analysis is applied in the data processing in training sets.

文摘：达到提出应用主成分分析法对样本进行预处理，减少网络的输入因子数，消除输入因子间的相关性并简化网络结构，达到提高网络学习速率的目的，得到的人工神经网络模型能达到所要求的精度。

When data are insufficient,chemical analysis of REE can be used to rebuilt the lithofacies paleogeography of sequence. This method is favourable for the analyses of source,reservoir and cap rocks in the sequence framework.

在缺乏其它资料的情况下，应用稀土元素地球化学分析方法可恢复地层层序的岩相古地理，指导层序地层框架内油气生、储、盖条件的研究。

The method of modeling and parametric estimation is an efficient technique for obtaining chemical information on material systems.It is one of the branches of the new frontier science—chemometrics.

模型建立和参数估计方法是获得物质系统化学信息的一种有效技术；是兴新的边缘学科——化学计量学研究的一个重要部分。

This rapid escalation danger is one of the key reasons why the Chemical Weapons Convention prohibits the use of even tear gas or pepper spray as a method of warfare.

CWC 的基本精神将土崩瓦解。世界将陷入新一轮的化学武器军备竞赛！尽管冷战已经早已停止。

The methods of mechanical compression, chemical extraction, soxhlet extraction and supercritical CO2 extraction were taken to extract the oil in perilla seed. With oil yielding rate of perilla seed after extraction as investigation index, the suitable extraction method for oil in perilla seed was screened.

方法］采用机械压榨法、化学萃取法、索氏提取法和超临界CO2萃取法提取紫苏子油，以紫苏子萃取后的出油率为考察指标，筛选适宜的紫苏子油的提取方法。

The method inducing periodontitis animal model contains biological,physical,chemical,and various kinds of environment factors.

建立牙周病动物模型的方法，主要是用生物的、物理的、化学的和各种环境因子作用于实验动物。

The structure and chemical bonds of 1 phenyl silatrane have been studies by ab initio method.

本文用量子化学从头计算方法研究了1－苯基杂氮硅三环的电子结构和化学键。

Good knowledge of the chemical and physical property and the test method.

掌握良好的化学和物理性能知识及测试方法？

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％。