溶剂法提取香薷黄酮化合物的研究

采用溶剂法提取香薷中黄酮化合物,并进行单因素工艺考察,筛选出最佳的提取条件.在单因素基础上,利用响应面分析法考察乙醇浓度、提取温度及物料比对提取香薷总黄酮的影响,并在各影响因素合理值内修正最佳工艺条件.结果表明,香薷总黄酮最佳提取工艺条件为提取时间1h,乙醇体积分数70％,提取温度70℃.     

美伐他汀提取工艺研究

研究从发酵液中提取美伐他汀的工艺条件。通过单因素实验确定了从美伐他汀发酵液中提取美伐他汀的最佳工艺条件。结果表明,醋酸丁酯作为提取溶剂时,其最佳工艺条件如下:提取温度为50℃,物料比(醋酸丁酯体积(mL):菌丝质量(g))为8:1,提取时间为3 h,闭环温度为70℃,闭环时间为6 h。本工艺简便,收率高,适用于工业化生产。     

消肝脂颗粒乙醇提取工艺的研究

目的优选消肝脂颗粒乙醇提取部分工艺条件。方法采用正交试验法,以姜黄素提取率和浸膏收率为考察指标,优选乙醇回流提取部分的工艺条件。结果本方乙醇提取最佳工艺条件为：加6倍量80％乙醇,回流提取2次,每次1h。结论该工艺为确保有效成分的浸出提供了实验依据．     

酸性离子液体[Emim]HSO4催化合成丁二酸二乙酯

采用两步法合成并表征了酸性离子液体[Emim]HSO4,并用于催化合成丁二酸二乙酯,考察了醇酸物质的量比、反应时间、反应温度、催化剂用量对酯收率的影响。其最佳工艺条件如下:n(乙醇)∶n(丁二酸)=3∶1、反应温度为70℃、反应时间为4h、催化剂用量为总质量的5%。在此最佳反应条件下酯收率可达75.02%。考察了酸性离子液体重复使用性能,离子液体重复使用7次后,催化活性基本不变。     

星点设计-响应面法优化知母总皂苷提取工艺

目的 :采用星点设计-响应面法优化知母总皂苷提取工艺。方法 :以知母皂苷元为指标,选取乙醇作为提取溶剂,以乙醇浓度、固液比、提取时间、提取次数为自变量,知母总皂苷提取效率为因变量,采用星点设计-响应面法对知母总皂苷提取工艺参数进行优化。结果 :确定了知母总皂苷提取最佳条件:乙醇浓度70%、固液比1:6、提取时间75分钟、2次提取为最优条件。结论 :该工艺可用于知母总皂苷提取,工艺流程简单,预测性好。     

甲醇电氧化制备甲醛的研究

介绍了一种用电化学法合成甲醛的新方法,研究了甲醇和盐酸混合体系中各种工艺条件对甲醛收率的影响,得到最佳电解条件如下:电极电流密度为20 mA/cm2,电解温度为40℃,电解时间为6 h,甲醇初始浓度为0.5 mol/L,盐酸初始浓度为1 mol/L。在此条件下电解甲醇,甲醛收率达19.1%,电流效率为28.8%。     

3,3,17,17-亚乙二氧基-7-羰基-雄烯二酮的合成研究

以雄烯二酮为原料,经3,17位亚乙二氧基化,7位烯丙位氧化合成了目标化合物3,3,17,17-亚乙二氧基-7-羰基-雄烯二酮,总收率为45.2%。目标化合物和中间体的结构经IR,1 H NMR和MS确证。3,3,17,17-亚乙二氧基-7-羰基-雄烯二酮烯丙位氧化的最佳合成条件如下:n(PDC)∶n(t-BuOOH)∶n(3,3,17,17-亚乙二氧基-雄烯二酮)=4∶4∶1,反应温度为25℃,反应时间为5h。此合成方法反应原料易得,反应条件温和且产率高。     

重齿鳞毛蕨中总黄酮的含量测定

黄酮类化合物具有抗癌、抗氧化、抗炎、保肝护肝、调节免疫等药理作用,一直受到国内外研究人员的高度重视。研究采用分光光度法测定了重齿鳞毛蕨(Dryopteris juxtaposita)中总黄酮的含量,并研究了提取试剂种类、试剂浓度、料液比、提取时间对总黄酮提取率的影响。结果表明采用体积分数75%乙醇加热回流180min,料液比为1g∶12mL时提取液中总黄酮提取率最高,其平均提取率为1.056%。由于此含量测定方法准确度高,操作简单,因此可作为一种高效便捷测定重齿鳞毛蕨中总黄酮含量的方法。     

重齿鳞毛蕨中总黄酮的含量测定

黄酮类化合物具有抗癌、抗氧化、抗炎、保肝护肝、调节免疫等药理作用,一直受到国内外研究人员的高度重视。研究采用分光光度法测定了重齿鳞毛蕨(Dryopteris juxtaposita)中总黄酮的含量,并研究了提取试剂种类、试剂浓度、料液比、提取时间对总黄酮提取率的影响。结果表明采用体积分数75%乙醇加热回流180min,料液比为1g∶12mL时提取液中总黄酮提取率最高,其平均提取率为1.056%。由于此含量测定方法准确度高,操作简单,因此可作为一种高效便捷测定重齿鳞毛蕨中总黄酮含量的方法。     

辛伐他仃的合成工艺改进探讨

目的：对辛伐他汀的合成工艺进行探讨,不断改进新型还原酶抑制剂辛伐他汀的合成工艺。方法：以洛伐他汀作为原始材料,经过酰胺化、选择性酯化、甲基化、水解等反应,合成辛伐他汀。结果：目标化合物辛伐他汀经过核磁共振进行确证,其总收率70%以上。
　　结论：本方法进行辛伐他汀的合成,缩短了药物反应的时间,简化了合成的步骤,因此应该在药物生产中积极推广。     

两种有色植物染色的尝试

柑橘皮和黑莓都是天然植物染料,橘皮染色的性质相对于黑莓染色稳定,橘皮和黑莓等植物类染色原料染色是环保的染色方式,能减少环境污染,节省能源,相对合成染料非常廉价。可能有些种类容易褪色,但是值得推广的染色方式。     

基于正交试验设计对柚皮果胶提取工艺的优化

基于四因素三水平的正交试验设计,确定提取柚皮果胶的较佳工艺条件:在95℃、pH值1.5的条件下,使水与干柚皮以15∶1比例混合,浸提60min。通过进一步的单因素优化试验,发现:1)微波加热辅助萃取可大大缩短浸提时间,以6min为佳;2)乳酸更有利于果胶的溶解,其得率可达17%;3)在果胶制备过程中,建议使用干柚皮为原料,但不必使用活性炭脱色。     

Estimating switching costs involved in changing mobile phone carriers in Japan: Evaluation of lock-in factors related to Japan’s SIM card locks

This paper employs a web-based conjoint-type questionnaire to examine empirically user preference for a hypothetical Subscriber Identity Module (SIM) unlock situation in Japan’s mobile phone market. This paper also analyzes carriers’ other marketing strategies to lock in consumers. The empirical analysis in this study reveals the following: over 80% of survey respondents evaluate a highly compatible platform with the SIM unlocked. Approximately 70% of consumers find that the value of discounts on initial payments exceeds the discounts on one-year monthly payments. In addition, conditions set by continuing agreements for mobile carriers and mobile handsets reduce consumer benefit by 35% at the median in the case of SIM unlocking with compatible platforms.     

蒽醌废酸生产碱式氯化铝的研究

以苯酐法生产蒽醌时所产生的含氯化铝的废盐酸为原料 ,采用中和法制备碱式氯化铝。通过最优化实验确定了生产的最佳工艺条件为 p H=2 .3～ 2 .5,反应温度 60～ 70℃ ,反应时间 90 min,熟化时间 4～ 6d,反应收率可达 61 % ,产品符合化工部标准 ( HB/T2 677-95) ,可进行工业化生产 ,同时对企业的废物再利用提供了新途径。     

Consumer willingness to pay for redundant food labels

Previous studies, as well as market sales data, show some consumers are willing to pay a premium for redundant or superfluous food labels that carry no additional information for the informed consumer. Some advocacy groups have argued that the use of such redundant labels is misleading or unethical. To determine whether premiums for redundant labels stem from misunderstanding or other factors, this study seeks to determine whether greater knowledge of the claims - in the form of expertise in food production and scientific literacy - decreases willingness to pay for redundant labels. We also explore whether de-biasing information influences consumers’ valuations of redundant labels. An online survey of 1122 U.S. consumers elicited preferences for three redundantly labeled products: non-GMO sea salt, gluten-free orange juice, and no-hormone-added chicken breast. Respondents with farm experience report lower premiums for non-GMO salt and no-hormone-added chicken. Those with higher scientific literacy state lower premiums for gluten-free orange juice. However, after providing information about the redundancy of the claims, less than half of respondents who were initially willing to pay extra for the label are convinced otherwise. Over 30% of respondents counter-intuitively increase their premiums, behavior that is associated with less a priori scientific knowledge. The likelihood of “overpricing” redundant labels is associated with willingness-to-pay premiums for organic food, suggesting at least some of the premium for organic is a result of misinformation.     

成品油销售综合经营指标三级预警机制探索--中国石油陕西销售公司的经营实践

2018年以来,中国石油陕西销售公司采用"红橙黄"经营指标三级预警机制,把复杂的量价关系、促销经营和费用成本管控,通过指标量化。一是以经营活动分析为基础,围绕业务指标、财务指标及支撑体系,建立了综合经营指标长效预警机制。二是通过大数据平台,形成业务运行数据每日监控,实现对月度指标的跟踪预警。中国石油陕西销售公司以"红橙黄"经营指标三级预警为抓手,将综合指标评价理念贯穿到经营全过程中,为生产经营活动提供了直观的决策依据,实现了提质增效的目标。     

Dream or reality: providing universal access to basic telecommunications in Nigeria?

Nigeria has publicly announced its intentions to make basic telecommunications, specifically telephones, affordable and universally available to its people. However, several issues make this proposition especially difficult for countries such as Nigeria. For instance, Nigeria's population is large at 110 million with less than 1% presently able to access telephones. Furthermore, over 70% of Nigerians, the majority of them poor, live in rural areas where telephone lines do not presently exist. This paper studies the universal service proposition viz a viz these conditions by analyzing Nigeria's attempts to provide telephone service since the country's independence in 1960. The paper notes impending problems with Nigeria's attempts to achieve critical mass, which is essential for universal access. Ultimately, it suggests various strategies that the country should use to stimulate critical mass and achieve universal access.