近红外光谱法快速检测赤芍配方颗粒 芍药苷和浸出物含量

为了直接、快速地测定赤芍配方颗粒中芍药苷和浸出物的含量,解决回流烘干法测定耗时长、操作繁琐等问题,利用近红外漫反射技术,结合偏最小二乘法(PLS),建立了测定芍药苷和浸出物含量的近红外光谱测定方法。选用积分球系统测定样品的近红外光谱,定量模型的预处理方法采用多元散射校正和一阶导数进行处理,光谱范围分别为5 492～5 103cm-1,7 428～7 201cm-1,6 942～5 322cm-1。结果表明,定量模型中芍药苷含量和浸出物含量的最佳主因子数分别为7和6,内部交叉验证均方差分别为0.082 6和0.226 0,决定系数(R2)分别为0.981 7和0.982 4,系统精密度RSD值分别为1.1%和0.9%,方法精密度RSD值分别为2.1%和1.6%,外部验证预测均方差分别为0.363和0.282。采用建立的近红外预测模型对赤芍配方颗粒进行快速测定,方法可行,分析快速、简便,结果准确,为赤芍配方颗粒的测定提供了高效方法。     

HPLC-DAD测定仙鹤草配方颗粒中3种成分

为了建立同时测定仙鹤草配方颗粒中芦丁、槲皮苷、木犀草素含量的有效方法,通过对流动相、检测波长、提取溶剂及提取方式等因素进行考察,最终确定了采用HPLC-DAD法同时测定仙鹤草配方颗粒中的3种成分,采用InertSustain AQ-C18色谱柱(4.6mm×250mm,5μm),以乙腈-0.5%醋酸为流动相,流速为0.8mL/min,检测波长为360nm,柱温为35℃。结果表明,芦丁、槲皮苷、木犀草素分别在0.216~5.410,0.185~4.635,0.147~3.680μg范围内呈现良好的线性关系,R2分别为0.999 5,0.999 6和0.999 7,平均回收率(n=6)分别为101.5%,100.1%和99.5%。该方法快速准确,专属性强,可用于仙鹤草配方颗粒的质量控制。     

基于UPLC特征图谱与主成分分析的白芷配方颗粒质量评价

为了评价不同厂家白芷配方颗粒的产品质量,建立了白芷配方颗粒的特征图谱与主成分分析方法。采用Waters Uplc Class H超高效液相色谱仪与Agilent Zorbax Eclipse Plus C18(2.1mm×100mm,1.7μm)色谱柱,以乙腈-水为流动相,柱温为25℃,流速为0.2mL/min,检测波长为254nm,利用指纹图谱相似度评价软件提取白芷配方颗粒特征图谱中的特征成分,使用参照物标定5个特征峰的成分;采用SPSS 19.0软件进行主成分分析,给出了不同厂家白芷配方颗粒在2个主成分上的分布图,并对不同厂家白芷配方颗粒进行了综合评分。结果表明:10批白芷配方颗粒特征图谱确定的13个特征峰中,指认出了花椒毒酚、水合氧化前胡素、欧前胡素、蛇床子素、异欧前胡素5种成分;以回归得到的3个主成分的矩阵回归系数与方差贡献值的乘积之和作为10批样品的综合评分,排名第一的综合评分为1.77。基于UPLC特征图谱与主成分分析法能够快速、有效地检测和评价白芷配方颗粒。     

液压传动系统的故障分析与排除（十一）

第十讲故障分析实例(2) YT32-500型万能液压机,适用于塑性材料的压制。也可用于校正、压装、砂轮成型、粉末制品、冷挤压金属零件成型及塑料制品压制成型工艺等。一、YT32-500型万能液压机液压传动系统该液压机的液压传动系统(见图),主液压缸能完成滑动横梁快速下行、慢速压制、保压、回程和悬空停止动作;顶出液压缸实观顶出、回程和任意位置静止等动作。1.主缸运动(1) 主缸活塞快速下行按下起动按钮,电磁     

红外诊断技术与应用（四）——第三讲 红外仪器（续）

第三讲　红外仪器 (续 )　　四、红外热像仪1 光机扫描红外热像仪光机扫描红外热像仪基本构成见图 8,其基本原理是 :被测物体表面的温度分布借助于红外辐射到光学系统 ,又被光机扫描机构扫描成像在探测器上 ,再由红外探测器转换成视频电信号 ,经过放大后送到终端显示出被测物体的热图像。图 8　光机扫描热像仪基本构成原理框图2 焦平面热像仪焦平面热像仪革除了繁杂的光机扫描装置 ,它的红外探测器呈二维平面形状 ,被测目标的红外辐射只需通过物镜聚焦成像在红外探测器的阵列平面上 ,即可实现红外光电转换和信号处理。焦平面热像仪成像机理…     

HPLC法同时测定薄荷配方颗粒中6种成分的含量

为了提高薄荷配方颗粒的质量标准,建立其多指标定量评价体系,采用HPLC法同时测定薄荷配方颗粒中咖啡酸、橙皮苷、迷迭香酸、香叶木苷、香蜂草苷和蒙花苷6种成分的含量。采用Poroshell 120 EC-C_(18)(4.6 mm×250 mm, 5μm)色谱柱,以甲醇(A)-乙腈(B)-5%冰乙酸(C)为流动相,梯度洗脱,流速为0.6 mL/min,柱温为35℃,咖啡酸、迷迭香酸、蒙花苷的检测波长为330 nm,橙皮苷、香蜂草苷的检测波长为284 nm,香叶木苷的检测波长为380 nm。结果表明,薄荷配方颗粒中6种待测成分的线性关系、分离度、重复性均符合要求,各成分的平均回收率分别为99.19%,98.06%,100.45%,98.90%,100.17%,99.78%。不同厂家的薄荷配方颗粒中6种化学成分的含量存在一定差异。建立的HPLC分析方法简便、快速、准确,可以为薄荷配方颗粒的质量控制提供方法参考。     

佛手标准汤剂中两种成分的测定方法研究

为提高佛手配方颗粒的质量评价标准,利用佛手标准汤剂控制佛手配方颗粒的内在质量。以15批不同产地的佛手饮片为原料,制备佛手标准汤剂,建立含量测定方法,以柚皮苷、橙皮苷为指标成分,测定了15批佛手标准汤剂的相关含量。结果表明:柚皮苷、橙皮苷分别在0.025 1～0.125 5,0.160 5～0.802 3μg范围内线性关系良好(r=0.999 9),平均加样回收率分别为102.27%和101.48%,重复性考察RSD值分别为0.78%和0.89%,12 h稳定性考察RSD值分别为0.59%和1.46%。所提出的方法能同时测定柚皮苷和橙波苷两种成分,节约了分析时间,提高了佛手产品的质量标准。     

浮小麦配方颗粒特征图谱及4种核苷类成分定量研究

为了实现浮小麦配方颗粒的质量控制和评价,采用高效液相色谱法,以Waters XSelect^? HSS T3(4.6 mm×250 mm, 5μm)为色谱柱,在甲醇-水为流动相、梯度洗脱、柱温为30℃、流速为1.0 mL/min、检测波长为260 nm的条件下,建立了浮小麦配方颗粒的特征图谱及4种核苷类成分的含量测定方法。共确定了13批浮小麦配方颗粒特征图谱中的8个共有峰,并全部获得指认,分别为尿嘧啶、胞苷、次黄嘌呤、尿苷、腺嘌呤、鸟苷、色氨酸、腺苷,各共有峰相对保留时间的RSD均小于2.0%。尿嘧啶、尿苷、鸟苷、腺苷分别在0.001 9～0.047 3 mg/mL、0.003 9～0.098 2 mg/mL、0.002 8～0.070 1 mg/mL、0.002 9～0.073 0 mg/mL范围内线性关系良好(r=1.000 0),平均加样回收率分别为99.0%、100.7%、101.2%、101.8%。所建立的核苷类成分含量测定方法准确、高效、重复性好,可用于浮小麦配方颗粒的质量控制。     

碳纳米管增强水泥基复合材料的 二维代表单元研究

为了从细微观尺度上研究碳纳米管-水泥基复合材料的损伤破坏过程和破坏机理,从碳纳米管-水泥基复合材料中选取尺寸为100μm×100μm的代表单元,建立二维代表单元的细微观层次的数值模型。以势能原理的基面力元法为理论基础,对代表单元进行数值模拟,探究在单轴受压状态下碳纳米管-水泥基复合材料的力学性能变化,并绘制破坏裂纹的发展过程图和最大主应力分布变化过程图。结果表明,该代表单元模型能够较真实地模拟复合材料在单轴压缩状态下的损伤破坏过程,通过数值模拟不同含量的复合材料代表单元模型,发现增强体的含量影响着复合材料的强度及韧性,选择合适的含量范围有利于提升材料的力学性能。通过数值模拟的方法分析碳纳米管增强水泥基复合材料的作用机理,拓展了基面力元法的应用范围,节约了计算资源,其结果丰富了碳纳米管-水泥基复合材料力学性能的研究,可为相关工程应用及基础研究提供参考。     

参桂前列爽胶囊质量标准研究

目的：制定参桂前列爽胶囊质量标准 方法：采用薄层色谱法对制剂中的桂枝、人参、甘草等进行TLC鉴别,采用HPLC对制剂中人参皂苷含量进行测定。结果：人参、桂枝、甘草供试品与对照品及对照药材色谱相应的位置上显相同颜色的斑点,阴性对照没有干扰。人参皂苷Rg1,Rc,Rb1在0.5-5μg范围内的线性良好（r〉0.999）,平均回收率分别为100.2％、99.7％、100.3％。RSD分别为：2.13％、2.10％。结论：以上方法可以作为参桂前列爽胶囊的质量控制。     

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。     

On the Intricacies of the Chinese Guanxi: A Process Model of Guanxi Development

Guanxi (personal connection) has been identified as a necessary condition to do business successfully in China. In this paper, we seek a clear conceptual understanding of this prevalent construct and propose a three-stage model of guanxi development so as to stimulate systematic research in this area. Our conceptual and theoretical discussion of guanxi bases,guanxi objectives, and the operating principles at different stages of guanxi development will also help practitioners to use guanxi more effectively.     

Firm Growth Under Sample Selection: Conditional <Emphasis>σ</Emphasis>-Convergence in Firm Size?

This paper tests the second, widely neglected implication of Gibrat’s law stating that the variance of firm size distribution increases over time. In contrast, learning models imply conditional σ-convergence in firm size. A unique data set of Austrian firms especially suited to account for sample selection effects is used to analyze the growth/size nexus of firms. The estimation results suggest that the predicted variance in firm size decreases only for firms of age 30 or below. For older age cohorts the hypothesis of a constant variance either cannot be rejected or increasing variances are found.     

The uniform distribution as a first practical approach to new product inventory management

It is common sense that the premises usually considered in inventory models have little applicability to new product inventory management. This paper develops a first practical approach to deal with this issue: the solution to the (Q, r) inventory model for uniform demand forecasts and lead-times. Based on the fact that the uniform distribution is defined by two parameters that are easy to estimate—maximum and minimum—this paper shows that such a premise may comprise a helpful and accurate decision support tool for managers until they begin to learn about the distribution characteristics of the demand during the lead-time.     

Getting consumers to eat more whole-grains: The role of policy, information, and food manufacturers

The 2005 Dietary Guidelines were unique because they offered quantitative recommendations for consumption of whole-grains. This case study examines the hypothesis that the changed recommendations were responsible for the recent increase in retail sales and consumption of whole-grain food products. We find that release of the Dietary Guidelines and related media attention did increase availability and sales of whole-grain foods. A large impact on consumption occurred through reformulation of existing products, induced by competition among food suppliers. This study reveals the key role product reformulation plays in inter-firm competition and in realization of dietary changes recommended by public policy.     

甘草SRAP-PCR正交试验设计优化及引物筛选

为了建立甘草SRAP技术,采用四因素(Taq酶,Mg~(2+),dNTP,引物)四水平的正交试验设计[L16(44)]对甘草进行SRAP-PCR试验,电泳结果采用软件SPSS分析,退火温度和引物筛选采用单因子试验。结果发现,4种因素对甘草SRAP-PCR的影响依次为dNTPTaq酶Mg~(2+)引物;优化后的甘草SRAP-PCR体系(20μL)为1×PCR缓冲液,引物0.6μmol/L,Mg~(2+)2.5mmol/L,Taq酶1.5U,dNTP 0.3mmol/L,模板DNA 40ng;最佳的退火温度为50℃;81对引物中有22对扩增出明亮、清晰的谱带。该优化的SRAP-PCR反应体系为进行甘草资源遗传分析提供了技术支持。     

Gibrat's Law: Are the Services Different?

Several noted surveys on intra-industry dynamics have reached the conclusion from a large body of evidence that Gibrat's Law does not hold. However, almost all of these studies have been based on manufacturing or large scale services such as banking and insurance industries. There are compelling reasons to doubt whether these findings hold for small scale services such as the hospitality industries. In this paper we examine whether the basic tenet underlying Gibrat's Law– that growth rates are independent of firm size – can be rejected for the services as it has been for manufacturing. Based on a large sample of Dutch firms in the hospitality industries the evidence suggests that in most cases growth rates are independent of firm size. Validation of Gibrat's Law in some sub-sectors of the small scale services suggests that the dynamics of industrial organization for services may not simply mirror that for manufacturing. The present paper includes a survey of nearly 60 empirical studies on firm growth rates.     

Knowledge and Values in Technology Education

This paper addresses two closely interrelated issues in Technology Education: knowledge and values. The starting point for the discussion is analysis of the nature of knowledge in technology education. Approaches for theorising knowledge will be analysed in this paper as well as problems associated with them. Three major types of problems are identified: problems with finding an appropriate approach for the analysis of technological knowledge; problems with a technocratic interpretation of technological knowledge for the purpose of its classification; and problems with establishing a consistent approach to distinguish common features of technological knowledge. A model that represents knowledge in technology education and the place of values in it is presented as a way of overcoming the problems specified. The claim is made that understanding of knowledge/values relationships can improve theoretical understanding of how technology education can be constructed.     

瓜蒌配方颗粒指纹图谱研究

为了全面反映瓜蒌配方颗粒所含多种组分,明确瓜蒌配方颗粒HPLC指纹图谱的测定方法,对10批瓜蒌配方颗粒进行了HPLC指纹图谱测定及相似度评价。采用HPLC方法,色谱柱为GL Sciences公司InertSustain AQ-C_(18)柱(4.6 nm×250 nm,5μm),以甲醇-0.1%甲酸水溶液为流动相,梯度洗脱,检测波长为260 nm,流速为0.8 mL/min,柱温为25℃,对瓜蒌配方颗粒指纹图谱测定结果进行了相似度评价。结果表明,10批瓜蒌配方颗粒指纹图谱中呈现16个共有峰,相似度均大于0.960,表明瓜蒌配方颗粒具有良好的一致性;此外,在16个共有峰中指认出腺嘌呤、尿苷2个化学成分。瓜蒌配方颗粒指纹图谱反映了瓜蒌配方颗粒的多组分面貌,可为瓜蒌配方颗粒的多组分质量控制提供参考依据。