Box-Behnken响应面法优化徐长卿配方颗粒挥发油-β-CD包合物制备工艺

为了解决徐长卿挥发油加油难及加入后的稳定性问题,采用Box-Behnken响应面法,优选出徐长卿配方颗粒挥发油-β-CD包合物的制备工艺。在单因素试验的基础上,采用3因素3水平Box-Behnken设计对徐长卿配方颗粒挥发油-β-CD包合工艺进行优选,以挥发油包合率及包合物收率为考察指标,考察挥发油与β-CD比例、包合温度、包合时间对结果的影响。结果表明:优选的包合工艺条件为挥发油与β-CD质量比为1∶8.34,包合温度为50.2℃,包合时间为2.17 h。在此条件下,挥发油包合率为72.19%,包合物收率为75.06%,综合评分为96.41,RSD值为1.1%。优选的包合工艺包合率高,工艺稳定可行,可为配方颗粒挥发油的工业化生产提供数据支持。     

蓝莓花色苷提取工艺的优化研究

以体积分数为0.1%的盐酸乙醇溶液为提取液,探讨蓝莓果实花色苷的最佳提取工艺。采用单因素和正交设计来考察乙醇体积分数(A)、料液比(B)、温度(C)、时间(D)、火力(E)在水浴法、微波法和超声波法3种提取方法中的作用。通过光谱扫描确定了蓝莓花色苷的最大吸收峰在535nm处,水浴法、超声波法和微波法提取蓝莓果实花色苷的最佳工艺分别为A3B3C2D3,A3B2C1D3和A2B2C2E3。品种间花色苷的最适宜提取方法亦有所不同:超声波法最优,适于北陆和乔治2个品种;微波法次之,适于伯克利品种;水浴法提取效果最差。     

青风藤配方颗粒的制备及与传统汤剂的比较

为了研究青风藤配方颗粒制备工艺以及对青风藤配方颗粒与传统汤剂进行定性定量比较,运用正交试验方法,采用干法制粒,以出膏率、青藤碱含量为指标,优选青风藤配方颗粒制备工艺;采用薄层色谱法进行定性比较;以青藤碱为对照品,采用高效液相色谱法进行定量比较。青风藤配方颗粒最佳制备工艺如下:提取2次,加水量18倍(第1次加水量为10倍,第2次加水量为8倍),各煎煮1.0h。TLC结果显示,配方颗粒与传统汤剂化学成分的类型无明显差异。5批青风藤配方颗粒青藤碱含量分别为1.56%,1.58%,1.31%,1.20%和1.78%;5批青风藤传统汤剂青藤碱含量分别为0.94%,0.96%,0.85%,0.82%和1.02%。青风藤配方颗粒与传统汤剂中化学成分的类型基本相同,但青藤碱含量差异较大。     

超声水提秦艽中龙胆苦苷的工艺优选

优选出秦艽中龙胆苦苷的提取最佳工艺,采用正交试验法,以龙胆苦苷的质量分数为指标,考察了溶剂用量、提取时间、提取次数及提取温度对秦艽中龙胆苦苷提取率的影响,优选出合理的提取工艺。结果得知,蒸馏水用量为15 mL、提取时间为40 min、提取次数为2次、提取温度为40℃为最佳工艺条件,经验证性实验证明所优选条件可靠,适合秦艽中龙胆苦苷的提取。     

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．     

正交试验法优选超临界CO2流体萃取丹参中丹参酮工艺的研究

研究了超临界CO2流体萃取法萃取丹参中丹参酮的最佳工艺条件,以丹参酮ⅡA含量为指标,用高效液相色谱法测定,采用L9(34)正交试验法对丹参中丹参酮的提取工艺进行优选。结果表明,萃取压力对萃取结果影响最为显著,最佳萃取压力为25 MPa,萃取温度为40℃,无水乙醇用量为30%(质量分数),萃取时间为2 h。     

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。     

Y/β(Na)改性及对模拟汽油吸附脱硫的研究

以Ce-Y/β(Na)、Ba-Y/β(Na)和Y/β(Na)为吸附剂,对以噻吩为溶质、正己烷为溶剂的模拟汽油进行吸附脱硫,分别考察吸附时间、吸附剂与模拟油质量比和吸附温度对脱硫效果的影响。结果表明,以Ce-Y/β(Na)为吸附剂具有较高的吸附活性,在剂油质量比为1:20、吸附时间为4h、吸附温度为80℃时,脱硫率可达90以上。     

微波辅助水蒸汽蒸馏提取沙姜挥发油的研究

微波辅助提取技术源于上世纪80年代,它具有所需溶剂量少、溶解时间短等特点,这项技术被广泛应用在食品和农业等领域.微波辅助提取精油技术已经有多种形式,从最开始的微波辅助提取技术发展到微波辅助水蒸汽蒸馏等技术,而本文正是基于对微波辅助水蒸汽蒸馏技术的研究.通过将微波辅助水蒸汽蒸馏和传统蒸馏方法相结合,并用质谱色谱法进行鉴定,再用GC-MS离子流峰面积归一法对挥发油进行定量分析.由此得出实验结论:微波辅助水蒸汽蒸馏法和传统蒸馏方法得到挥发油成分大都相同,但是微波辅助水蒸汽蒸馏法比传统蒸馏方法收率较高.微波辅助水蒸汽蒸馏法是无污染、高收率的提取香料植物油的一种方法.     

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。     

基于Fluent的波节管内流体流动与传热特性研究

为了深入研究影响波节管传热效果的主要因素,应用CFD软件Fluent对波节管内流体的流动和传热特性进行数值模拟,分别研究了不同入口流速v(0.3,0.5,0.7和0.9 m/s)、波峰直径D_1(28,30,32,34和36 mm)、弧形段长S_1(34,23,17,13和10 mm)下波节管内流体的流动与传热特性。结果表明,不同型号波节管的努塞尔数(Nu)、流体压力损失以及综合性能随着入口流速的增加而增加;随着波峰直径D_1(弧形段长S_1)的增大,波节管的Nu先增大后减小,最后趋于一个相对稳定的值。当波节管的波峰直径D_1=34 mm时,波节管的传热性能最好,流体压力损失最大,综合性能最好;弧形段长S_1=23 mm时,波节管的换热性能最佳,流体压力损失最大,综合性能最好。通过参数正交分析可知,影响波节管传热效果的因素由强到弱依次为入口流速v、波峰直径D_1、弧形段长S_1。研究成果可为工程实际中提高波节管传热性能提供理论指导。     

成型磨齿机磨削烧伤的分析和防止措施

就如何减少大型重载齿轮的磨削烧伤,结合生产实际,分析了成型磨削原理、磨削烧伤的成因和检测方法,并就影响磨削烧伤的机床磨削方法、表面渗碳浓度、渗层显微组织、砂轮和修整轮、对中过程、切削参数、冷却液和辅助工艺进行了探讨,提出了相应的措施.     

Evaluating the impact of Tax-for-Fee reform (Fei Gai Shui) on water resources and agriculture production in the Zhanghe Irrigation System, China

This article questions the effectiveness and viability of rural Tax-for-Fee reform (Fei Gai Shui) on water resources and agriculture production, taking the Zhanghe Irrigation System of China as a case study example. The Fei Gai Shui reform has been heralded as a possible solution for reducing the excessive fiscal burden on peasants. While the reform may achieve in relieving peasant burdens significantly, the initial impact of Fei Gai Shui on water resources and agricultural production indicate least satisfactory trends. The policy shows significant impact on rice yield and area. It might also have profound impact on cropping pattern but it has yet to be seen. Dependence on local water resources such as ponds show significant increase after Fei Gai Shui as it discouraged farmers to rely on regional water sources. Although the lower regional water use under Fei Gai Shui reduced the water charges paid by farmers, the savings were mostly offset by increasing pumping costs in accessing water from local ponds. Without any adjustments, the Fei Gai Shui is likely to cause serious predicament in agricultural sector. It is visioned that local water resources such as water ponds will continue to play an important role in sustaining agricultural production.     

Time compression (dis)economies: An empirical analysis

Research Summary: To investigate time compression diseconomies (TCD), this study estimated time–cost elasticities using 459 oil and gas global investment projects (1997–2010). Results show that the average cost of accelerating investments is negative: a firm could cut $6.3 million in costs of a single project by accumulating asset stocks 1 month faster. About 88% of the projects exhibit negative time–cost elasticities with over 39% of unrealized economies of time compression. Only 12% of the projects are subject to TCD. These time inefficiencies or frictions do not negate the existence of TCD, but suggest they are less prevalent than assumed in the literature. Management experience, R&D investment, firm size, economic development, and political stability are shown to be associated with greater time compression efficiency. Managerial Summary: How fast should firms invest? The conventional view is that acceleration increases market revenues but also inflates costs. However, there is no recent empirical evidence of this tradeoff. Our article systematically investigates the costs of compressing time in investment projects. Results show that most firms in the oil and gas industry are significantly time inefficient in their operations. Specifically, by accelerating investments, firms would also substantially decrease costs. We estimate the magnitude of these time inefficiencies for specific oil and gas industries and firms and study which strategies might mitigate this problem. This fine‐grained analysis should help firms assess their financial incentives to accelerate projects and prove informative to stock market analysts’ valuations of firm investment timing.     

山楂多糖分散片的制备及质量控制

为优化山楂多糖分散片的制备工艺,对其进行了质量控制。在单因素试验的基础上,以崩解时间为评价指标,选用压片压力、崩解剂用量、乙醇溶液浓度为因素,利用正交试验对山楂多糖分散片的制备工艺进行优化;按照《中华人民共和国药典》的方法,对主药含量、崩解时间、分散均匀性、溶出度等指标进行测定,以期对山楂多糖分散片的质量进行控制。得到山楂多糖分散片的最优制备工艺如下:采用交联聚乙烯基吡咯烷酮(PVPP)为崩解剂,碳酸钙为填充剂,体积分数为65%的乙醇溶液为黏合剂,滑石粉为润滑剂,压片的压力为6kg。研究表明,该分散片每片含山楂多糖40mg,崩解时间为65s,分散均匀性良好,15min溶出度为标示量的75.40%。     

基于流管法的面积波及效率计算方法研究

中国已开发的大多数油田,经过多年的加密调整和注水开发,目前已处于高含水或高采出程度阶段,开采和稳产难度越来越大。因此,对注水开发油田进行水驱面积波及系数的研究意义重大。根据注水油田的基本特点,基于流管法建模基本原理,建立了五点法流管模型,利用BeckleyLeverett方程,结合单元分析法和流线积分法,对注水油田五点法井网面积波及效率的计算公式进行了详细推导,绘制并分析了面积波及系数和采出程度随时间的变化曲线。结果表明:当无流管突破时,注水油田的面积波及系数随时间的增加而线性增大;当主流管突破见水后,波及系数增大程度越来越慢,最后趋于平缓。当油田被注入水完全波及后,继续利用注水提高采收效果的作用很小,水驱效率明显降低。研究结果对于注水油田面积波及系数的求解及水驱动态开发规律的研究具有借鉴意义。     

Economic design of an chart for short-run production

The aim of this paper is to present an economical design of an X chart for a short-run production. The process mean starts equal to μ₀ (in-control, State I) and in a random time it shifts to μ₁>μ₀ (out-of-control, State II). The monitoring procedure consists of inspecting a single item at every m produced ones. If the measurement of the quality characteristic does not meet the control limits, the process is stopped, adjusted, and additional (r-1) items are inspected retrospectively. The probabilistic model was developed considering only shifts in the process mean. A direct search technique is applied to find the optimum parameters which minimizes the expected cost function. Numerical examples illustrate the proposed procedure.     

滏阳河邯郸段CODCr降解系数研究

降解系数的确定是水环境容量核算的关键因素。通过现场水团追踪实验,采用一维稳态水质模型进行参数率定;同时进行了室内模拟研究,运用最小二乘法进行回归计算,综合考虑2种方法测定结果,得到滏阳河邯郸段枯水期CODCr降解系数为0.152~0.270d-1;平水期CODCr降解系数为0.209~0.384d-1;丰水期CODCr降解系数为0.215~0.437d-1。     

Scale matters: The scale of environmental issues in corporate collective actions

Research Summary: Much of the research on corporate collective action to manage common pool resources is focused on coordinated actions, such as voluntary programs, rather than collaborative actions, such as technology sharing. In this article, we examine inductively the collective actions taken by a consortium of 12 oil sands companies to address three environmental issues of different scale. We identified a set of organizing rules that determined whether the relationship among industry members would be collaborative or competitive, and found that the organizing rules for collaborative collective action were more effective for smaller scale issues (i.e., tailings ponds and water) than the larger scale issue (i.e., greenhouse gas emissions). Our findings contribute to research on the competitive dynamics of collaborating with competitors and on industry self‐regulation. Managerial Summary: Many environmental issues, such as climate change, water quality, and contaminated land, are caused by the overexploitation of commonly shared natural resources. Firms will often overuse resources because their cost of use is less than the benefit that accrues. In Alberta’s oil sands, 12 of the major oil sands operators, all competitors, have agreed to collaborate by sharing technology, which goes against the received wisdom of competition. This multiparty collaboration among competitors, while still relatively rare, is becoming increasingly commonplace. In this article, we outline the rules that allow this collaboration to flourish. Our most important finding is that the rules are shaped by the scale of the issue being managed, not the size of the collaboration.     

Johnson's algorithm: A key to solve optimally or approximately flow shop scheduling problems with unavailability periods

Johnson's algorithm (JA) is perhaps the most classical algorithm in the scheduling area. JA gives the optimal solution to the two machine flow shop to minimize the makespan in polynomial time. Researchers have tried to extend this notorious result to obtain polynomial time algorithms for more general cases. Such importance motivated us to devote this paper to JA applied to three flow shop problems with unavailability periods to minimize the makespan. First we focus on the optimality condition of JA. Then we propose a modification of JA. After we calculate new performances of JA as a heuristic. Last we deal with an extension of JA.