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探讨了生产某些合成染料、药品和农药所需的中间体1,3-二甲基-吡唑啉酮〔5〕的合成方法。采用甲基肼为原料合成了产物,并研究了反应温度、物料的滴加速度和馏水量对产物收率的影响。 相似文献
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2-已酮糖有四种同分异构体,分别是山梨糖、塔格糖、阿罗酮糖和果糖.酮糖被还原时理论上生成一对等量的差向异构体糖醇.果糖是人们最了解的典型的也是自然界中存在最普遍的2-已酮糖.本文从解析果糖的一些特性为切人点介绍2-已酮糖的一些共同的还原特性. 相似文献
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主要研究了以N-甲基二乙醇胺(MDEA)在CuO/Cr2O3/Al2O3催化剂催化下脱氢制备4-甲基-2-吗啉酮(MMO),采用FT-IR、1H-NMR、GC-MS对MMO进行了表征,实验成功制备了MMO;考察催化剂的组分和比例对脱氢制备MMO的影响,结果表明当催化剂nCu:nCr:nAl=2:2:1时,CuO/Cr2O3/Al2O3催化剂的脱氢效果最为理想;研究反应条件对MMO的产率、转化率,确认最佳反应条件是反应温度为260°C-320°C,氢醇比为5.2-6.2,MDEA转化率达到100%,同时MMO产率最高达99.8%。 相似文献
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建立了气相色谱-质谱法同时测定UV油墨中紫外光引发剂二苯甲酮和4-甲基二苯甲酮含量的分析方法,并对提取溶剂、提取方式和提取时间进行了讨论。结果表明:两种目标物在0.5-10mg/L范围内线性关系良好(r均为0.9999),在高、中、低3个添加水平下,平均回收率为80.0%-97.8%,相对标准偏差(n=6)为0.8%-6.1%。本方法具有操作简单、快速等特点,能够满足对UV油墨中二苯甲酮和4-甲基二苯甲酮两种紫外光引发剂的分析要求。 相似文献
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本研究以新疆口岸进境的哈萨克斯坦产棕皮亚麻籽及未经化学改性的压榨亚麻籽毛油为试验样品,采用顶空固相微萃取技术萃取挥发性成分,气相色谱-质谱联用技术分析鉴定亚麻籽油中的挥发性成分,鉴定出冷榨亚麻籽油中挥发性组分:醇类>醛类>酸类>烷烯类>酮类>杂环类>酯类,主要挥发性成分有正己醇、正戊醇、正己醛、E,E-3,5-辛二烯-2-酮、正己酸、2-戊基呋喃等;鉴定出经150℃烤籽的亚麻籽油中挥发性组分:杂环类>醇类>醛类>酮类>烷烯类>酸类>酯类,主要挥发性成分有2,5-二甲基吡嗪、2-甲基吡嗪、2-乙基-5-甲基吡嗪、吡咯、Z-6-辛烯-2-酮、E,E-2,4-庚二烯醛等,应用建立的方法对未经化学改性的哈萨克斯坦产压榨亚麻籽毛油挥发性成分进行分析鉴定比对。研究发现,哈萨克斯坦亚麻籽油采用两种工艺(冷榨工艺和低于120℃炒籽压榨工艺)获得,保留了亚麻籽油的天然风味,更有益于人体健康。研究结果可为哈萨克斯坦亚麻籽油品质鉴定、归类化验及溯源提供技术支持。 相似文献
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老年人心理健康影响因素的调查研究——从人格特征与应对方式二因素分析 总被引:10,自引:0,他引:10
人格特征和应对方式对老年人心理健康具有重要影响。采用艾森克人格问卷(EPQ)、应对方式问卷和心理健康症状自评量表(SCL-90),对老年人人格特征、应对方式和心理健康作了问卷调查。人格特征对老年人心理健康具有直接的影响作用。外向型性格有利于老年人心理健康,神经质性格不利于老年人心理健康;人格特征还通过应对方式对老年人心理健康具有间接的影响作用。外向型性格老年人常用求助的应对方式,它更有利于心理健康,神经质性格老年人常用自责的应对方式,它更不利于心理健康。 相似文献
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基于灰色关联模型的计量分析,发现地区商贸流通业发展与公路交通基础设施水平具有较强的关联性:在公路里程、公路客运量、公路货运量和民用汽车拥有量中,民用汽车拥有量是最重要的影响因素,公路货运量次之;在社会消费品零售总额、市的零售额、县的零售额、县以下的零售额、批发和零售业零售额、住宿和餐饮业零售额中,公路交通基础设施对县以下的零售额的影响程度最大,对批发和零售业零售额的影响程度次之。 相似文献
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This study elucidates the causal relationships between service recovery, perceived justice, perceived risk, and customer value. Data were collected by questionnaires validated for reliability and validity. The findings were as follows: perceived justice is positively affected by service recovery, whereas perceived risk is negatively affected by perceived justice. Furthermore, perceived risk is directly and negatively affected by service recovery; perceived risk is also indirectly influenced by service recovery through perceived justice. Finally, customer value is affected by perceived risk. However, customer value is not directly related to perceived justice; customer value was found to be indirectly affected by perceived justice through perceived risk. Therefore, the path of this casual relationship is ‘service recovery, perceived justice, perceived risk then customer value’. Future studies may explore the influence of internal factors or dimensions of the forgoing variables on perceptions of customer value. In practice, hotel managers can refine the relevant service recovery approach and optimize financial investment to increase customer value. 相似文献
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Hong-Sheng Chang 《The Service Industries Journal》2013,33(1):73-84
The purpose of this paper is to elucidate how service quality cues and customer value are related, and explores the internal composition of this relationship. Samples were collected using a questionnaire, which had assessed the quality of the researcher's measurement efforts by investigating reliability and validity. Functional value is found to be affected mainly by reliable cues and accuracy of service quality, whereas conditional value is influenced by responsiveness of service quality. Furthermore, emotional value is found to be affected mainly by empathy of service quality, whereas social value is influenced by tangible cues of service quality. Finally, epistemic value is affected by responsiveness service quality. For future research, other external cues may influence perception of customer value with extrinsic information should be discussed. In practice, hotel managers can hone the relevant cues and optimise investments to raise service quality. Finally, this study provides a new shape of ‘structural’ relationships among five service quality cues and five types of customer value. 相似文献
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2-噻吩乙胺合成技术进展 总被引:5,自引:0,他引:5
2-噻吩乙胺是重要的医药中间体,本文主要介绍了2-噻吩乙胺的三条合成路线技术进展,一是噻吩经过甲酰化后与硝基甲烷缩合经乙硼烷还原得到噻吩乙胺;二是以噻吩为原料经过Vilsmeier反应后,与氯乙酸异丙酯进行Darzens反应,然后对产物2-噻吩乙醛进行还原得到2-噻吩乙胺;三是以噻吩为原料,与甲醛和氯化氢反应得到2-氯甲基噻吩,在经过取代和LiA1H4还原得到。 相似文献
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钢铁行业盐酸酸洗的环境影响评价 总被引:2,自引:0,他引:2
钢铁行业大量使用盐酸酸洗工艺。盐酸酸洗产生氯化氢废气、漂洗酸性废水、废盐酸。通过氯化氢的物料平衡,估算污染排放源强。国家鼓励的废酸处理技术是废酸焙烧再生回收技术。酸性废水的处理要通过曝气处理,避免出水返黄。氯化氢废气经密闭收集罩收集后采用洗涤塔处理。在环境影响评价中要重视对环保治理措施的论证,重视物料平衡分析和清洁生产分析。 相似文献