objective to analyze the spectrum features of nasalized vowels after the obturator application and to assess its value.

studies on the spectrum features of nasalized vowels

腭裂儿童鼻化元音的频谱特点研究

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by testing the first parameter to a static stringutils method, you avoid the trap of trying to write a string method that ( nonsensically) compares this to null.

通过在StringUtils的静态方法中判断第一个参数，您可以避免在编写String方法的代码时必须加入诸如判断this是否为null这种无意义的代码。

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there are lodging houses in this locality, but he did not even enter one, finding nothing which suited him.

这一带原有一些供人租用的房舍，但是他甚至进都不进去，因为他没有找到合适的。

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see through the trick of pettifogging "fu hui"

识破诡辩的“附会”把戏

provided by jukuu

and while she hesitated, from the room above came the soft, racking, petitionary music of a violin.

就在爱伦犹豫不决的时侯，楼上传来了温柔、凄婉、肯切的小提琴声。

provided by jukuu

the utility model belongs to the article packing belt technical field, in particular to a poly-rib belt with a plurality of thick ridges.

本实用新型属于一种物品的包裹带技术领域，特别涉及一种带多根粗棱线的包裹用多棱带。

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discussion on reasons of burning loss, unfixing and drop, wreckage caused by connection between graphite electrode and nipple and suitable solutions

从机械加工角度探讨石墨电极与接头连接烧损、松脱、折断的原因及解决方法

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a wing nut is a nut with wings.

蝶形螺母是一种翼状物的螺母。

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the solid dimethyl dially ammonium chloride was synthesized with dimethyl amine and allyl chloride as raw materials by the method of double liquid phases and two steps.

以甲苯为有机相溶剂，二甲胺（水溶液）和烯丙基氯为原料，采用双液相二步法合成了固体二甲基二烯丙基氯化铵。

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study on synthesis of carbamate by carbonylation of dimethyl carbonate and organic amine

碳酸二甲酯与有机胺羰基化合成氨基甲酸酯的研究

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long chain monoalkyl dimethyl tertiary amine, as an important material of surfactant, is widely used in textile industry, petroleum, cosmetic, and other daily chemicals and etc., and cannot be substituted by other chemicals.

长链单烷基二甲基叔胺，是表面活性剂的重要原料，它在纺织、石油、化妆品、日化等行业有着广泛的用途，具有其它化学品不可替代的地位和作用。

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the synthetic technological conditions of dodecyl dimethyl tertiary amine oxide were studied by orthogonal experiments. the optimum synthesis conditions were obtained in the presence of catalyst.

采用正交试验法对十二烷基二甲基氧化胺的合成工艺条件进行了研究，获得了在催化剂存在下的最优合成条件。

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catalyst is one of key issues in the process of amination of fatty alcohol with dimethylamine for preparation of long chain alkyl dimethyl tertiary amine.

脂肪醇在催化剂作用下直接胺化催化反应是目前生产长链烷基二甲基叔胺的主要工艺。该工艺的技术关键之一在于其催化剂。

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long chain monoalkyl dimethyl tertiary amine, with content of 98.5%, can fully satisfy requirements of various customers.

工业化生产的长链单烷基二甲基叔胺产品含量均在98.5%以上，完全可以满足各种不同用户的需求。

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study on the synthesis and application of dodecyl dimethyl tertiary amine oxide

十二烷基二甲基氧化胺的合成及应用研究

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the newly developed catalyst dl-03 for industrial use is able to satisfy the aliphatic alcohol one-step synthesis of dialkyl methyl amine and alkyl dimethyl amine. the scaling-up in a 500 t/ a unit has been successfully done in one time.

开发的DL&03工业催化剂满足了醇一步法制单、双长链烷基叔胺反应，并在500t/a装置上进行放大，一次获得成功。

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in this paper, an easy synthesis method of novel 12-3-12 gemini cationic surfactant were introduced from dodecyl dimethyl amine and epichlorohydrin in the lab. the structures of the product were characterized by the methods of ir and elemental analyzer.

以十二叔胺与环氧氯丙烷为主要原料，在实验室合成12-3-12型Gemini阳离子表面活性剂，终产物用傅立叶红外变换仪和元素分析仪进行定性分析，并对表面活性剂的性能进行了详细讨论。

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finally, gemini cationic surfactants were prepared by reaction of hexadecyl amide propyl dimethyl amine and bis ( 2-hydroxy-3-chloropropyl) alkylamines.

最后以十六酰胺丙基二甲基叔胺和二（2-羟基-3-氯丙基）烷基胺为原料反应制备Gemini阳离子表面活性剂。

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a new method of spectrophotometric determination of trace amount of chromium(ⅵ) with high sensitivity-tetrakis ( 4 dimethyl amine ammonium phenyl) porphyrin

超高灵敏度测定水中痕量铬（Ⅵ）的新方法&四（4-二甲胺苯基）卟啉分光光度法

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comparison between loop reactor and agitating reactor in producing dodecyl dimethyl amine

环路反应装置与搅拌釜装置生产十二烷基二甲基叔胺的比较

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