查询词典 acetaldehyde

In four flavor models, isoamyl alcohol model and ethyl acetate model have good capacity for simulation and prediction, whereas acetaldehyde model and diacetyl model do not.

在建立的4个风味物质模型中，异戊醇和乙酸乙酯模型的仿真能力和预测能力都比较强，双乙酰和乙醛模型的仿真能力和预测能力都比较差，需要进一步研究。

The glyoxal and glyoxalic acid contents in the solution of oxidation of acetaldehyde to glyoxal by nitric acid were determined by this method, the repeatabilities of analysis results were excellent and the relative error compared to chemical analysis of glyoxal was 1.77%.

用HPLC测定乙醛硝酸氧化法制乙二醛反应液中乙二醛和乙醛酸的含量，结果的重复性好；对乙二醛的测定结果与应用化学分析法测定结果的平均相对误差为1.77%；对反应液中乙二醛、乙醛酸含量的测定有着较高的加标回收率，分别为99.6%～103.3%和98.1%～102.4%。

The major causes of off-flavour of the cooked rice was due the intractions among rice proteins, lipids and carbohydrates, which result in the production of carbonyl compounds,the increase of caproaldehyde,and the decrease of acetaldehyde and mercapto group as well as the changes in the cell wall structures.

本文结合近几年研究工作及国内外对大米陈化研究的新进展，综合阐述了随大米存放时间的延长，其化学组织特别是大米蛋白质、类脂与淀粉的共同作用，促使羰基化合物的生成、乙醛减少、己醛增加、SH基减少，以及胞壁改变，是造成大米陈化、米饭&陈米臭&的主因。

Metaldehyde, a solid tetramer of acetaldehyde with low toxicity, has been widely available in commercial molluscicide preparations.

聚乙酸是种低毒性的乙酸之四聚或六聚化合物，目前在台湾被广泛地使用於诱杀蜗牛上。

Secondly, the silver based catalysts modified by phosphorus, zirconium, zinc, potassium and so on using molecular sieve as carrier, which were produced by ion-exchange method, had also good catalytic performance for 1,2-propane glycol oxidation to methylglyoxal. The conversion of 1,2-propane glycol and the selectivity of methylglyoxal were both high, and the impurity such as formaldehyde and acetaldehyde in the product is little. At the condition of the temperature 300 ℃, the molar ratio of oxygen to 1,2-propane glycol 1.7:1, the space velocity 6000h~(-1), and the concentration of 1,2-propane glycol 70wt%, the conversion of 1,2-propane glycol is 90% and the selectivity of methylglyoxal is 45% on the Ag-P catalyst.

其次对采用离子交换法制备的负载在分子筛上的银系催化剂进行了研究，发现此催化剂在助催化剂磷、锆、锌、钾等的作用下对丙二醇的低温氧化脱氢具有很高的活性，可以得到较好的丙酮醛的收率，并且产物中的甲醛、乙醛副产物的量比较低；经过对Ag-P催化剂上反应条件的考察，发现当温度为300℃、氧醇比1.7：1、空速6000h~(-1)、丙二醇浓度为70wt%时，丙二醇的转化率为90%，丙酮醛的选择性为45%。

The regularities of the influence of various factors includingreaction temperature,reaction time,the ratio of formaldehyde to acetaldehyde,the quantity of alkali and the concentration of formaldehyde on the yieldsof pentaerythritol and dipentaerythritol were studied.

通过单因素实验，考察了反应温度、反应时间、甲醛与乙醛的配比等因素对单、双季戊四醇收率的影响。

In order to understand the changes in physiology and the storability of blueberry fruits introduced to southern part of China, and to provide scientific basis for suitable packaging materials, changes of total soluble solid content, vitamin C content, acetaldehyde content, ethanol content, protopectin content and anthocyanin content, respiration rate, polygalacturonase and pectinesterase activities, weight loss and rotted rate of blueberry fruit warn investigated. Different packaging films were used, and the storage temperature was under 2℃.

为了解引种到我国南方栽培的蓝浆果鲜果低温贮藏期间的生理变化状况，并为保鲜贮藏选择适宜的包装材料提供科学依据，研究了在2℃条件下，不同薄膜包装处理对蓝浆果果实贮藏期间可溶性固形物、维生素C、乙醛、乙醇、原果胶和花色苷的含量，以及呼吸强度、多聚半乳糖醛酸酶和果胶甲酯酶活性、失重率、腐烂率变化的影响。

The 2002 edition of "Hygienic Standard for Cosmetics" in the provisions of banned cosmetics has 496 kinds of chemical substances, while the 2007 version by the new and change, a total of 1286 kinds of banned chemicals, including chlorine acetaldehyde, chlorinated methane, trichloro toluene.

在&2002年版卫生标准的化妆品禁止在化妆品的规定&的496种化学物质，而新的变化，但一千二百八十六种禁止化学品，包括氯乙醛，氯化甲烷，三氯共2007版甲苯。

The optimum conditions of synthesis were determined as follows:molar ratio of 2,4-di-t-amylphenol and anhydrous trimeric acetaldehyde 2∶1.2,amount of water 180 g,amount of emulsifier 0.5 g,and amount of catalyst 11.0 g at reacting temperature 80～83℃ for 5 h.

以2 ，4-二叔戊基苯酚、无水三聚乙醛为反应原料，采用含有表面活性剂、酸性催化剂的水作为反应溶剂，缩合反应合成2，2′-亚乙基双(4，6-二叔戊基苯酚)。

HCHO drops spirally along with the time,and but with transitory rises in summer,acetone and acetaldehyde decreases wavily.

空气中甲醛随使用时间的延长呈现伴夏季升高的螺旋样下降趋势；丙酮和乙醛呈波浪样下降；VOCs的污染水平使用初期最高，但下降较快，1个月后至初始的1/10～1/20。

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。