21 research outputs found

    Rapid Quality Control of Licorice in Its GAP Research

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    目的 建立甘草 GAP过程中的快速质量检验方法 ,为甘草药材的快速质量检测提供方法依据。方法 提出甘草中水溶性有效物质群的概念并建立其含量的比色测定方法。以甘草酸作为定量的标准物质 ,采用香草醛 -浓硫酸试剂作显色剂 ,用便携式小型光谱仪于 5 6 0 nm处检测。结果 回归方程为 Y=1.174 7C+0 .0 873,相关系数 r=0 .970 5 (n=3) ,回收率为 92 %~ 99% ,在 0 .0~ 0 .96 mg/m L 范围内仪器读数与甘草酸浓度呈线性关系。结论 该方法简单、快速、廉价 ,能够准确地反映甘草质量的优劣 ,适合在准确度要求相对较低的甘草生产基地推广使用Objective To develop a rapid method for the quality control of licorice in its GAP research.Methods Water-soluble triterpenoid saponins were defined as the active fraction in licorice and a colorimetric method using LED-based portable device has been developed for the first time to measure the content of this active fraction. The method was based on the specific color reaction occurring between triterpenoid saponins and vanillin-sulfuric acid reagent. Visible light absorption of 560 nm was chosen as the detection wavelength.Results The operating calibration curve(Y=1.174 7C +0.087 3 mg/mL) was found to be linear at the range of 0.0~0.96 mg/mL glycyrrhizic acid in water (r=0.970 5). The recovery is 92~99%.Conclusion The method is simple, rapid and low-cost and is recommendable to evaluate the quality of Glycyrrhiza uralensis Fisch. in its GAP research.内蒙梁外甘草 GAP研究与开发;; 国家自然科学基金 2 0 0 3重点项目 ( 2 0 2 3 5 0 2 0

    Development of HPLC fingerprint bar code technique for authentication and quality assessment of Radix Salvia Miltiorrhiza

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    目的 建立丹参水溶性有效成分 HPL C指纹条形码图谱 ,以此图谱鉴别不同来源丹参与其他鼠尾草属丹参伪品并进行质量评价。方法 以不同产地正宗丹参和市场上充作丹参的其他鼠尾草属植物为分析对象 ,选择适宜的水溶性成分萃取方法和 HPL C分析条件 ,构建丹参 HPL C指纹图谱 ,并进行归一化处理 ,将相同条件下的指纹条形码图谱相互进行比较。结果 所建立的构建丹参水溶性成分 HPL C指纹条形码图谱的方法有较好的重现性和稳定性。正品丹参药材有 18个共有指纹峰 ,各峰相对保留时间和峰面积的相对标准偏差分别小于 1.18%和 2 5 %。以原儿茶醛 (保留时间为 33.71min,RSD =1.5 % )为界 ,指纹图谱可分为非指纹区和指纹区两个区 ,非指纹区主要用于有效成分的半定量 ,指纹区则可同时用于鉴别和成分的半定量。其他鼠尾草属植物的指纹图谱与丹参有较大差异。其差异主要表现在指纹区中。结论 指纹条形码图谱技术能对丹参的道地性进行鉴别并对有关成分进行半定量 ,从而能对丹参品质进行全面评定Object To discuss the development of a “bar coded” HPLC chromatographic fingerprint system for the assay of water soluble components in Radix Salvia Miltiorrhiza (RSM) The technique has been used for the species authentication and quality assessment of RSM and other species of Salvia L. originated from different locations.Methods Authentic RSM species originated from different geographic locations were compared with different species of Salvia L. obtained commercially using an analytical protocol involving water extraction, followed by HPLC of the extract, and finally the normalization of all peak intensities in the HPLC chromatogram. The last step resulted in “bar coded” chromatograms which could be used as fingerprints for the qualitative and quantitative comparison of different species of Salvia L Results The HPLC bar code fingerprint was found to be highly stable and reproducible. A total of 18 common peaks were identified in the HPLC chromatogram with their average RSD of relative retention time and peak area less than 1.18% and 25%, respectively. Separated by the protocatechuic aldehyde peak (retention time 33.71 min and RSD of 1.5%), the HPLC chromatogram could be separated into two groups: the early eluting group of peaks in the “non specific” region, and the late eluting group of peaks in the “fingerprinting” region. The former group of peaks could be used for the semi quantification of bioactive components, whereas the later group of peaks could be used for both identification and semi quantification purposes. HPLC chromatograms of other species of Salvia L. showed fingerprints distinctively different from those of authentic species of Salvia L.; and the difference lay mainly in the fingerprinting region of the HPLC chromatograms Conclusion The developed bar coded HPLC chromatographic fingerprints can be used effectively for the authentication of species of Salvia L., and the quality assessment of RSM or its derived products based on the semi quantitative analysis of bioactive components in the samples香港创新科技署创新基金 (UIM/6);; 福建省青年科技人才创新项目(2 0 0 1J0 63

    Study on Optimal Harvest Time of Semi-wild Glycyrrhiza uralensis at Liangwai,Inner Mongolia

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    目的 :研究甘草中甘草酸的积累动态 ,确定内蒙古梁外地区育苗移栽的半野生甘草最佳采收期。方法 :用HPLC法测定不同时间采集的不同株龄的半野生甘草中甘草酸含量。结果 :甘草中甘草酸含量 6~ 7月份最高 ,8月份开始逐渐降低 ,11~ 12月最低 ,翌年 3~ 4月份开始逐渐增加 ,直到 6~ 7月份达最高峰 ;甘草在移栽后的前三年 ,甘草酸含量无明显增加 ,第四年的各个月份的甘草酸含量均远大于头三年。结论 :育苗移栽的半野生甘草的最佳采收期为移栽后的第四年 7~ 8月份Objective: To study the dynamic accumulation of glycyrrhizic acid(GA) in semi wild Glycyrrhiza uralensis Fisch. so as to determine its optimal harvest time Methods: The content of GA in the plant samples was determined by HPLC Results: In the same growth period, the content of GA in the plant reached its highest peak in June or July, decreased gradually from August, and reached the lowest in November or December. Then the content of GA increased gradually from next March, and finally reached the highest in June or July again There was no obvious difference between the content of GA in the one year old and the two year old Glycyrrhiza uralensis But the content of GA in the three year old increased markedly, and its GA content was much higher than that of the one or two year old Conclusion:The optimal harvest time of semi wild Glycyrrhiza uralensis is in July or August after transplanted three years国家自然科学基金 2 0 0 3年重点项目( 2 0 2 3 5 0 2 0

    橡胶轴承黏弹性和振动载荷耦合润滑特性研究

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    基于橡胶材料黏弹性,建立综合时变效应的无限长线接触轴承润滑模型。基于三参量固体蠕变模型,并耦合振动载荷对橡胶轴承进行了弹流润滑分析。计算并分析了3种振动载荷形势下,橡胶轴承润滑膜的最大压力和最小膜厚变化,并与不考虑蠕变影响的情况进行了对比。探讨了相同载荷、不同时刻下,橡胶轴承润滑膜压力和膜厚的变化。压力的求解采用了多重网格法,为了提高收敛精度,其底层采用了牛顿迭代,求解弹性变形采用了多重网格积分法。结果表明,在计入橡胶轴承的黏弹性时,润滑膜压力在随着振动载荷做同等形式振动的同时,在蠕变开始阶段,压力会取得较大的值,且随着运行时间的延长,整体下降并趋于稳定;相反,润滑膜厚度在随载荷做相反形式振动的同时,在开始阶段,膜厚会取得较小的值,且随着运行时间的延长,整体增大并趋于稳定;相同载荷下,随着时间的延长,承载区变大,润滑膜压力减小,膜厚变大

    基于谐响应分析的艉轴承动态特性研究及灵敏度分析

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    为了解决水润滑橡胶艉轴承运转过程中共振、鸣音的问题,基于ANSYS有限元分析平台,对艉轴承进行动态响应分析。首先,运用模态分析得到艉轴承的低阶固有频率及振型;其次,运用谐响应分析得到艉轴承随频率变化的响应规律,从而确定对艉轴承动态特性影响最大的固有频率;最后,对其结构参数进行灵敏度分析,得到振动特性的影响因子排序,为降低实验成本以及艉轴承的动态设计提供了依据

    基于有限长线接触的锥齿轮热弹流润滑分析

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    为了研究锥齿轮的热弹流润滑机理,基于弹性流体动力润滑理论,建立有限长线接触模型,研究了直齿圆锥齿轮热弹流润滑特性。首先,将直齿圆锥齿轮热弹流问题近似等效为两同向圆锥滚子的准稳态热弹流润滑问题,应用多重网格法和逐列扫描法求解了锥齿轮整个接触线上的油膜压力、油膜厚度及固体和油膜中层的温度。结果表明,直齿圆锥齿轮沿齿宽方向上各点的压力、膜厚、温度均不相同。其中,小端的油膜压力略大于大端的油膜压力;小端的油膜厚度小于大端的油膜厚度;沿齿宽方向的温度分布差异较为明显,油膜中层的温度大于两固体表面的温度。该研究为直齿圆锥齿轮的润滑设计提供一定的理论依据

    表面改性对滑动轴承弹流润滑的影响

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    考虑滑移边界条件,建立了极限剪应力模型和线接触弹流润滑模型,推导了润滑剂界面滑移速度,并修正了流体润滑Reynolds方程,针对界面改性后滑动轴承的润滑状态进行了探究。首先,分析了对轴瓦和轴颈界面均进行改性处理后,轴承润滑状态在整个弹流润滑接触区的变化;其次,分别研究了仅对轴瓦或者轴颈做改性处理的影响;最后,探究了界面改性对轴承摩擦因数的影响,并讨论了摩擦因数随载荷、速度的变化。结果表明,在弹流润滑的条件下,同时对轴瓦和轴颈进行表面改性处理时,油膜会在入口区形成凹陷,在出口区形成坍塌;仅对轴颈界面进行改性处理时,油膜会在整个接触区形成凹陷,对应的压力也会随之增加;相反,仅对轴瓦界面进行改性处理时,油膜厚度减小,压力降低;表面改性处理后,摩擦因数降低,并随载荷、速度的增大而减小

    汽车差速器锥齿轮差速工况下的热弹流润滑分析

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    为了研究差速器锥齿轮差速工况下的啮合热特性,基于热弹性流体动力润滑理论,建立了直齿锥齿轮非稳态热弹流润滑模型,分析了行星齿轮在差速下的温度场。首先,研究了行星齿轮与半轴齿轮在非牛顿流体作用下的热特性;其次,研究了差速工况下行星齿轮温度场随模数和齿宽的变化;最后,研究了差速工况下行星齿轮温度场随转速的变化。结果表明,行星齿轮沿齿宽方向的温度分布不同;行星齿轮本体最大温度随着齿宽增大而增大,随模数的增大而减小;差速器行星齿轮与半轴齿轮接触区的温度随转速的增大而增大。该研究为差速器锥齿轮润滑设计提供一定的理论依据

    修形对直齿锥齿轮弹性流体动力润滑的影响

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    为解决直齿圆锥齿轮的端啮问题,通过对直齿圆锥齿轮进行齿廓修形,提高小端的油膜承载能力,使得载荷沿齿宽方向分布均匀。齿廓修形先采用二次抛物曲线,再改变主动轮和从动轮的齿顶修缘高度,确定修形参数后,建立直齿圆锥齿轮无限长线接触弹性流体动力润滑模型,压力和膜厚采用多重网格法求解,弹性变形采用多重网格积分法求解。齿顶修缘后啮入点的油膜压力比原来小,油膜厚度变大;二次抛物曲线修形后,啮入瞬时点和啮出瞬时点的油膜压力在赫兹接触区明显降低,赫兹接触区的油膜厚度明显增大,沿啮合线分布的最大油膜压力降低,最小油膜厚度增大,中心油膜压力降低,中心油膜厚度增大;修形参数的变化影响修形后的油膜压力和油膜厚度;修形改变了齿宽方向的载荷分布,直齿圆锥齿轮的小端和大端的载荷差距减少,齿面载荷由端部向齿宽中部转移。研究结果说明,齿廓修形可以改善齿轮的润滑状况,提高啮合过程的油膜压力,减少齿面的摩擦和磨损,同时也可以避免齿面胶合的产生

    新型复合型艉轴承的流体特性研究

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    为了解决艉轴承在启停阶段造成的磨损和烧焦问题,基于有限元分析软件Fluent,提出了一种螺旋腔与阶梯腔复合形式的新型轴承。首先,运用流场分析对传统型轴承和复合型轴承水膜压力进行了数值仿真;其次将二者水膜压力积分,得到承载力,并分析转速对二者的影响;最后,运用ANSYS Workbench平台对复合型轴承进行流固耦合分析。结果表明,复合型轴承较传统型轴承,承载能力提高20%~30%,且变形主要集中在两端端泄处,为工程实际提供有效理论指导,具有较好的工程前景
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