空气中可吸入颗粒物的两种测定方法的比较

本文对测定空气中可吸入颗粒物的两种仪器TEOM系列1400A微量振荡天平法可吸入颗粒物监测仪与MP101M β射线法可吸入颗粒物监测仪进行了对比,并且给出了对比结果β射线法与微量振荡天平法测量结果具有较强相关性,两种方法都是可取的.     

空气中可吸入颗粒物的两种测定方法的比较

本文对测定空气中可吸入颗粒物的两种仪器;TEOM系列1400A微量振荡天平法可吸入颗粒物监测仪与MP101Mβ射线法可吸入颗粒物监测仪进行了对比,并且给出了对比结果：β射线法与微量振荡天平法测量结果具有较强相关性,两种方法都是可取的。     

HPLC及分光光度法测定胡椒碱含量方法在检测工作中的运用分析

本文结合笔者多年的工作经验,对HPLC及分光光度法测定胡椒碱含量方法及相关标准在检测工作中的运用进行了探讨分析,可供同行参考。     

两种残余应力测定方法的研究和比较

先用X射线衍射法再用盲孔法测定了同一试样的残余应力,对测试结果进行了分析比较。结果表明：对于残余应力分布不随深度改变的情况,两者结果一致;但对于其他情况,两种方法得到的结果不一致。通过测试残余应力沿试样深度的分布和从原理上比较两种测试方法的不同,得出盲孔法的测试结果受深层残余应力分布影响,而X射线衍射法的测试结果不受其影响。     

两种车用乙醇汽油调合组分油中MTBE测定方法的比较

采用气相色谱法和红外光谱法分析测定了同一批车用乙醇汽油调合组分油中的甲基叔丁基醚含量。结果表明,两种方法都能满足实际检测的需要,且无明显差异;但在重复性方面,红外光谱法一致性程度更好;在回收率实验中,气相色谱法更为稳定。     

两种测定三叶草中水分含量的方法比较

采用烘箱法和红外法两种不同的方法测定三叶草中水分含量,通过设置不同温度、不同时间和不同称样量测定三叶草水分含量,比较两种方法的精密度。结果表明：烘箱法测定三叶草含水率的最佳条件是称样量1g、温度110℃、时间6h,含水率为86.23±0.12%;红外法测定的最佳条件是称样量为1g、温度110℃、时间9min,含水率为81.34±0.62%。烘箱法的精密度高于红外法,应用中需准确测定水分含量时可优先考虑烘箱法。     

两种小麦粉中过氧化苯甲酰测定方法的对比分析

通过对现行两种小麦粉中过氧化苯甲酰的测定方法：GB/T 18415-2001和GB/T 22325-2008的测试比较,发现二者的差异与各自优势,为现实产品检测提供参考。     

超声波探伤中两种缺陷测长方法的比较

以钢板中规则缺陷以及平板对接焊缝缺陷为研究对象,按照JB/T4730.3-2005标准,利用横波探头对钢板中规则缺陷以及焊缝中已知缺陷用不同的测长方法测长,通过一系列的试验工作获取钢板及平板对接焊缝中缺陷长度的超声检测数据,并与缺陷的实际尺寸进行比较,为实际工作中选取恰当的缺陷测长方法提供有价值的参考。     

国内外几种微量水分测定方法和仪器的比较

工业生产中对净化气体的质量要求越来越高,其中对微量氧和微量水的监测越来越重要了。湿度的测定相对来说是较为困难的,尤其是低湿度的测量就更困难,尤其是低湿度的测量就更困难,本文就几种微量水分测定方法和仪器进行了优缺点对比分析。     

甘草酸的不同提取方法比较

目的比较水酸法和氨水法提取甘草酸含量的变化。方法利用正交试验4因素3水平选择最佳提取条件（包括加水量、提取次数、煮沸时间、粉碎时间、溶剂量、振荡时间、氨水浓度），用紫外分光光度法在252nm波长处测定甘草酸含量。结果每lOOg甘草粗粉用水酸法提取的最佳条件为：每次加水量2000mL，提取2次，煮沸5min，粉碎20s，氨水法最佳条件为：每次加0．4%氨水2000mL，振荡2h，提取2次。最终氨水法提取率为32％，水酸法提取率为26％。结论在最佳条件下，氨水法提取的甘草酸纯度和提取率明显高于水酸法。     

Enhanced solubility of piperine using hydrophilic carrier-based potent solid dispersion systems

Context: Piperine alkaloid, an important constituent of black pepper, exhibits numerous therapeutic properties, whereas its usage as a drug is limited due to its poor solubility in aqueous medium, which leads to poor bioavailability.

Objective: Herein, a new method has been developed to improve the solubility of this drug based on the development of solid dispersions with improved dissolution rate using hydrophilic carriers such as sorbitol (Sor), polyethylene glycol (PEG) and polyvinyl pyrrolidone K30 (PVP) by solvent method. Physical mixtures of piperine and carriers were also prepared for comparison.

Methods: The physicochemical properties of the prepared solid dispersions were examined using SEM, TEM, DSC, XRD and FT-IR. In vitro dissolution profile of the solid dispersions was recorded and compared with that of the pure piperine and physical mixtures. The effect of these carriers on the aqueous solubility of piperine has been investigated.

Results: The solid dispersions of piperine with Sor, PEG and PVP exhibited superior performance for the dissolution of piperine with a drug release of 70%, 76% and 89%, respectively after 2?h compared to physical mixtures and pure piperine, which could be due to its transformation from crystalline to amorphous form as well as the attachment of hydrophilic carriers to the surface of poorly water-soluble piperine.

Conclusion: Results suggest that the piperine solid dispersions prepared with improved in vitro release exhibit potential advantage in delivering poorly water-soluble piperine as an oral supplement.     

两种测量电压有效值方法的比较

为准确测量不同频率的交变电压有效值,介绍两种常用的测量方法——热等效法和公式计算法,并分析各自的特点。分别利用这两种方法搭建测量电路,对不同频率正弦波有效值进行测量。对测量数据进行分析,客观比较两测量电路的精度和频率响应。分析结果表明:热等效法适合测量高频信号的电压有效值,而公式计算法适合测量低频信号的有效值,该结论为不同场合测量有效值的各种应用做出参考。     

三维机织碳纤维/环氧树脂复合材料在两种测量方法下的热响应机制对比

采用瞬态热线法和闪光法分别测量了多种结构参数的三维机织碳纤维/环氧树脂复合材料的导热系数。通过对3D正交机织碳纤维/环氧树脂复合材料的有限元模拟可以看出,3D正交机织碳纤维/环氧树脂复合材料内经纱、纬纱和Z向纱的导热作用在不同的受热形式下会发生变化。采用瞬态热线法测量时,2.5D机织碳纤维/环氧树脂复合材料的导热系数低于2.5D经向增强结构,同时高于3D正交结构,而采用闪光法测量时,2.5D经向增强和3D正交碳纤维/环氧树脂复合材料的导热系数均小于2.5D机织结构。这是由于在使用不同的测量方法时,三维机织碳纤维/环氧树脂复合材料内部相同的纱线系统在导热过程中所起的作用并不相同。随着纤维体积含量的提高,瞬态热线法和闪光法测得的2.5D机织碳纤维/环氧树脂复合材料的导热系数都在不断提高。由于经纱的屈曲,采用闪光法测量时,导热性能提升更加明显。研究结果表明,三维机织碳纤维/环氧树脂复合材料在不同受热形式下具有不同的热响应机制。     

液闪测量3H活度TDCR与ESCR法的比较

基于TDCR与ESCR两种不同的液体闪烁测量方法,使用两台液体闪烁计数器分别测量3H系列猝灭源,探测效率均随着猝灭程度的增加而降低,TDCR方法具有较高的探测效率,且测量值的偏差总体较小;采用ESCR方法测量猝灭指数较大的3H样品时,宜提前基于所用闪烁液的体积对3H的优值因子进行调试,并使用多组低测量效率的猝灭标准源来拟合猝灭曲线。     

Bioanalytical method development and its application to pharmacokinetics studies on Simvastatin in the presence of piperine and two of its synthetic derivatives

Piperine has been widely used as a bioenhancer. Simvastatin belongs to a group of medicines known as statins. It acts by inhibiting HMG CoA reductase and acts primarily as a hypolipidemic agent. In this study some derivatives of Piperine were synthesized. They were studied for their bioenhencing effect (10?mg kg^?1) and this effect was compared with that of Piperine. The pharmacokinectic profile of Simvastatin alone and in combination with Piperine and Piperine derivatives were investigated by validated HPLC method as per USFDA guidelines. It was seen that the two synthesized derivatives of Piperine significantly improved the bioavailability of Simvastatin in Wistar rats. The 5-(benzo) [1,3]dioxol-5-yl)-N-(pyridin-4-yl)penta-2,4-dienamide was better amongst the synthesized in increasing the bioavailability of Simvastatin in Wistar rat.     

Industrial computed tomography image size measurement

As one of the most useful modern detection technologies, Industrial Computed Tomography (ICT) image size measurement can correctly non-destructively measure the size of workpieces’ inner construction, and it is considered as the standard for quality assurance and reverse engineering. In view of the advantages and disadvantages compared to conventional methods, this paper improves the precision of image size measurement with a new algorithm that uses an approximate function to describe edge degradation. First, this algorithm constructs the approximate function and determines the optimal point of edge detection, based on image intensity and inflexions. Then, in order to accurately extract the image edge, this algorithm is used to revise the primary image, completing construction of the CT image.Excellent results are obtained from simulations and experiments. The experimental results indicate that the relative error is 2% for the CT image when the step evolution of the image edge is pooled. The relative error of this method is decreased by as much as 1.5% compared to wavelet transformation and ridgelet transformation. Therefore, this new algorithm demonstrates increased effectiveness in extracting an accurate measurement of the CT image edge.     

Comparison of two high-precision nondestructive measurement methods for evaluating thermal expansion differences in the 8.3-m ultralow-expansion Subaru primary mirror blank

The building blocks for fabricating the 8.3-m Subaru primary mirror blank are ultralow-expansin solid hexagonal units that were subjected to rigorous ultrasonic examination to establish thermal expansion characterization as reported by Hagy [Appl. Opt. 12, 1440 (1973)]. Following assembly of the mirror by fusion and fine annealing, photoelastic analyses at hex-to-hex seals were used to calculate thermal expansion differences. These differences are found to be in excellent agreement with the ultrasonically established differences.     

Modeling breakage and motion of black pepper seeds in cryogenic mill

The present investigation aims to represent three-dimensional motion and breakage phenomena of black pepper seeds in the cryogenic mill (hammer mill) using discrete element method (DEM). In DEM modeling, bonded particle model was coupled with Hertz-Mindlin contact model. Calibration method was used to select appropriate model (bond) parameters. The calibrated set of bond parameters includes 3.12?×?10¹¹?Pa?m^?1 normal stiffness; 1.56?×?10¹¹?Pa?m^?1 shear stiffness; 3.88?×?10⁸?Pa critical normal stiffness; 1.94?×?10⁸?Pa critical shear stiffness. Besides, the validity of calibrated parameters was tested in the hammer mill. The observed qualitative and quantitative results (breakage and flow pattern) of numerical and experimental approaches were in good agreement. Based on these results, a few prefatory suggestions were provided to improve the design aspects of the mill. Overall, DEM modeling offered a better understanding of particle breakage and flow pattern in the mill.     

Comparison of two post-calibration correction methods for complex permittivity measurement of biological tissues up to 50 GHz

Two correction methods are discussed in this paper to remove residual errors due to the lack of repeatability of coaxial-to-microstrip launchers as part of the TRL calibration procedure. These methods are applied for accurate insertion loss measurement of biological tissues embedded in a two-port microstrip test fixture, from which the tissues' complex permittivity values are extracted for frequencies between 15 and 50 GHz. In the first method, distilled water is used as a calibration standard as part of a two-port calibration procedure. The second method identifies an error transfer function using the difference between simulated and measured insertion loss for distilled water, and then applies it as a correction factor to the measurement results for biological tissues. Both methods are compared in terms of extracting the accurate complex permittivity of brain matter.