查询词典 reagent

PTFE slurry in HNO〓 was used as fluorinating reagent to convert the silica matrix into high-volatile fluoride, which was subsequently evaporated by selective vaporization prior to the atomization of analytes.

首次报道了以PTFE为氟化剂，通过高温氟化反应和选择性蒸发原位分离基体硅的新方法。

Chiral nonracemic fluoro-organic molecules with a fluorine atom on a stereogenic center are readily prepared via chiral electrophilic fluorinating reagent-mediated enantioselective fluorinations, substrate-controlled enantioselective electrophilic fluorinations, chiral metal complexes and asymmetric catalyst—directed catalytic enantioselective fluorinations.

高光学活性的手性氟化物可通过手性亲电氟化试剂诱导的立体选择性氟化反应，基于底物的手性氟化反应以及手性催化剂诱导的不对称催化氟化反应等来制备。

X-ray fluorescence spectrometry ; multi-element determination ; mixed flux ; glassing reagent ; copper concentrate

X射线荧光光谱法；多元素测定；混合熔剂；玻璃化试剂；铜精矿

According to the Box-Benhnken design principle,the method of response surface method with 3 factors and 3 levels was used. The factors influencing the technological parameters were determined by means of regression analysis. Response surfaces were finally graphed with the yield as the response value. The synthesis conditions were optimized as follows:reaction reagent was NBS,stoichiometric proportion between NBS and anhydrovinblastine was 1.07; the dosage of TFA was 22 mL/L; reaction temperature was －68 ℃ and duration was 90 min.

在单因素实验基础上，根据Box-Benhnken实验设计原理，采用三因素三水平的响应面分析法，研究了各个因素及其交互作用后，得到了合成7′-Br-脱水长春碱的最佳工艺条件：以二氯甲烷为溶剂，采用NBS为溴代剂，其用量与底物的物质的量比为1.07∶1，TFA的加入量22 mL/L，在－68 ℃下反应90 min，终止反应后，得到卤代产物。

Recent progress of dimethyl carbonate which acted as methylating reagent in methylation reaction s that took place on carbon, oxygen, nitrogen and sulfur atoms was reviewed.

综述了碳酸二甲酯作甲基化试剂在碳、氧、氮和硫原子上进行甲基化反应的研究进展，提出了今后研究工作的发展方向。

Dimethyl carbonate was used as the methylating reagent, o-vanillin as the material and K2CO3 as the catalyzer to synthesize oV. The effect of material ratio, reaction time, reaction temperature and catalyzer dosage on its synthesis reaction was investigated.

方法］采用碳酸二甲酯作为甲基化试剂，以邻位香兰素为原料，无水碳酸钾为催化剂，合成邻藜芦醛，研究物料配比、反应时间、反应温度和催化剂量对反应的影响。

In cases where more than one transfection reagent can be used, we highlight the reagents we recommend for most robust performance.

在能够使用一种以上转染试剂的情况中，我们对能显示强健性能的试剂进行标记。

Research in three aspects is studied in this thesis:(1) Through many experiments,the effects of mixed acid nitratiny reagent and its constitute and the proportion of reactant,as well as the reaction temperature and time ,on the nitrating reaction were studied.

本课题主要做了三个方面的研究：(1)硝化工艺采用硫酸硝酸组成的混酸硝化，通过实验来确定适宜的物料配比、混酸的组成、温度和反应时间以及分析这些因素对反应的影响。

The total reaction could be explained by two steps.The first was a fast pre-equilibrium,activation nitrating reagent transferred to the catalyst.

反应共分两部进行：第一步是快速的预平衡步骤，活性硝化剂转移至催化剂上；第二步是缓慢的速率控制步骤，粘结在催化剂上的活性硝化进攻试剂与底物反应生成目标产物。

To determinate the concentration of TiO_2 in functional fiber for labeling purpose,the sample was nitrified with burning and dissolved in mix acid as pretreatment and then its concentration of TiO_2 was determined by spectrophotometric method with ascorbic acid as shelter reagent of Fe~(3+) and Cu~(2+) and diantipyryl methane as developer at wavelength λ=390 nm.

针对功能纤维中添加TiO2的含量测定问题，对功能纤维样品采用高温消化、混酸溶解的前处理方式，以抗坏血酸作Fe3+、Cu2+的掩蔽剂，二安替比林甲烷作为显色剂，用分光光度法在λ=390 nm波长处测定功能纤维中纳米TiO2的含量。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。