超声波提取-火焰原子吸收光谱法测定金银花中的Fe、Cu和Pb

建立了湿法和超声波提取处理样品,火焰原子吸收光谱法测定金银花湿法消解液及超声波提取液中Fe,Cu和Pb元素含量的方法.金银花中3种元素的含量Fe＞Cu＞Pb,硝酸作为提取剂,提取元素的溶出率的大小:Cu＞Pb＞Fe,回收率为85％-107％,RSD为0.6-1.0％.结果表明,超声波提取能较好地提取金银花中微量元素,元...     

常见饮料中咖啡因的拉曼光谱定性检测

利用激光拉曼光谱仪在微弱光信号检测方面的优点,用测试范围200nm-800nm,测试精度0．1nm的激光拉曼光谱仪对几种常见饮料进行测试,将265nm处咖啡因特征峰作为判断依据,定性检出饮料中含有咖啡因。     

主振荡功率放大装置中的放大自发辐射效应和能量提取效率

 建立了放大自发辐射(ASE)和相干激光能流耦合的模型,使用迭代算法,计算了长方体形状放大级中的ASE能流和相干激光能流的分布以及放大级出口0.5 m处的ASE分布,并讨论了入射光强、饱和光强对输出功率及能量提取效率的影响。对于增益区呈长方体、增益系数沿流场方向呈抛物线分布的放大级的计算结果表明：输入光的存在不仅会降低放大级中ASE光强的大小,而且将改变ASE的分布,使放大级中ASE能流的极大值向入口处移动;在饱和光强一定的情况下,输出功率和能量提取效率将随着入射功率的增大而增大;在入射光强一定的情况下,输出功率将随着饱和光强的增大而增大,而能量提取效率将随着饱和光强的增大而减小。     

珙桐叶总黄酮提取工艺及体外抗氧化性

运用正交试验设计探讨了绵竹白云山珙桐叶黄酮的微波辅助提取工艺条件,并对提取液的抗氧化性能进行了研究。结果表明,珙桐叶总黄酮提取的最佳工艺参数：微波功率700W,料液比（g/mL）1∶40,乙醇质量分数浓度为70%,提取时间为2min,测得每克干叶中总黄酮含量为71.03mg。对提取液的抗氧化性研究表明,珙桐叶总黄酮对超氧阴离子自由基、羟基自由基的清除率较好,在实验所选浓度范围内,总还原能力随浓度增加而增强。     

动态光谱的单拍提取

为了提高动态光谱(dynamic spectrum,DS)数据处理方法的效率与精度,采用单拍提取技术,即对所采集全部波长对应的光电容积脉搏波(photoelectric plethysmography,PPG)叠加平均所得到的全波段PPG,以单个脉搏为周期,提取其上升沿作为模板;用该模板校正各个波长PPG的上升沿,再以...     

透镜检测中复合自动对焦技术的研究及应用

针对光学透镜参数测量系统中的对焦问题,设计了一种粗精结合的复合自动对焦方案.在粗对焦过程中,选用全局图像的方差函数作为清晰度评价函数,用均值比较的爬山法实现焦面搜索,并用三点法判断初始对焦方向.在精对焦过程中,利用基于数学形态学的条件膨胀算法和形状因子提取目标图像,并以日标图像区域内的Brenner函数作为清晰度评价函...     

Simulation of ion beam extraction and focusing system

The characteristics of ion beam extraction and focused to a volume as small as possible were investigated with the aid of computer code SIMION 3D version 7. This has been used to evaluate the extraction characteristics (accel-decel system) to generate an ion beam with low beam emittance and high brightness. The simulation process can provide a good study for optimizing the extraction and focusing system of the ion beam without any losses and transported to the required target. Also, a study of a simulation model for the extraction system of the ion source was used to describe the possible plasma boundary curvatures during the ion extraction that may be affected by the change in an extraction potential with a constant plasma density meniscus.     

Study of the THGEM detector with a reflective CsI photocathode

The THGEM detector without and with a CsI has been tested successfully. The optimal parameters of THGEM have been determined from eight samples. The UV photoelectric effect of the CsI photocathode is observed. The changing tendency related to the extraction efficiency (ε_extr) versus the extraction electric field is measured, and several electric fields influencing the anode current are adjusted to adapt to the THGEM detector with a reflective CsI photocathode.     

A fast and efficient mesh segmentation method based on improved region growing

Mesh segmentation is one of the important issues in digital geometry processing. Region growing method has been proven to be a efficient method for 3D mesh segmentation. However, in mesh segmentation, feature line extraction algorithm is computationally costly, and the over-segmentation problem still exists during region merging processing. In order to tackle these problems, a fast and efficient mesh segmentation method based on improved region growing is proposed in this paper. Firstly, the dihedral angle of each non-boundary edge is defined and computed simply, then the sharp edges are detected and feature lines are extracted. After region growing process is finished, an improved region merging method will be performed in two steps by considering some geometric criteria. The experiment results show the feature line extraction algorithm can obtain the same geometric information fast with less computational costs and the improved region merging method can solve over-segmentation well.     

Isolation of Hemicellulose from Wood Chips via Extraction with Kraft Green Liquor

<正>The present paper covers the extraction of hemicelluloses from woods,i.e.,Eucalyptus Globulus,white fir and Douglas fir via green liquor pretreatment and alkali post-treatment with sodium hydroxide.The effects of such extraction conditions as extraction time,temperature on the yields of hemicellulose and the degree of deliginification were investigated.Sugar analyses using Dionex indicate that xylose,glucose and mannose are the main sugar types present in the hemicellulose from Eucalyptus.Other sugar components such as arabinose and galactose were also found in Dogulas fir hemicellulose.The highest yield of hemicellulose was 8.4%for Eucalyptus extracted with green liquor at 130℃for 3.5 h.Further sodium hydroxide extraction for 5 h gave a hemicellulose yield of about 20%.The use of green liquor for the extraction of wood hemicellulose is believed to be the first attempt.