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861.
一种基于算法融合的红外目标跟踪方法   总被引:8,自引:3,他引:5  
视频目标跟踪的难点在于快速、准确地在帧与帧之间匹配目标.由于红外图像目标与背景的反差低,图像的边缘模糊并且灰度级动态范围小,使红外目标跟踪难度比可见光更大.本文提出一种针对红外日标跟踪的融合算法,该方法融合直方图和不变矩的特点.首先利用目标的直方图计算简单快速的特点,由均值平移算法快速找到局部最优解,但由于该局部最优解仪为直方图匹配的最优解,缺少目标形状特征,与实际目标位置存在一定的偏差;其次,利用边缘小变矩作为修正特征修正误差,避免跟踪误差逐渐累计而最终导致跟踪失败,以提高跟踪的稳定性和精度.实验结果表明,该算法能够消除跟踪过程中的漂移现象,提高跟踪精度.  相似文献   
862.
863.
建立了X射线荧光光谱法测定绿泥石中镁、铝、硅、磷、钾、钙、钛、铁元素含量的快速分析方法。以标准物质及标准物质与基准试剂氧化镁、氧化钙人工混合配制标样的方法建立标准工作曲线,重点讨论了熔剂和脱模剂的选取。最佳熔样条件:采用8.0g四硼酸锂和偏硼酸锂混合熔剂(质量比67: 33)+0.8g样品并添加溴化锂作为脱模剂,熔样温度1100℃,熔样时间10min。该方法相对标准偏差(n=12)均小于5.57%,绿泥石样品测定结果与化学法一致,硅酸盐标准物质测定结果均满足不确定度要求。  相似文献   
864.
Polyphenolic acids are the widely occurring natural products in almost each herbal plant, among which rosmarinic acid (RA, C18H16O8) is well-known, and is present in over 160 species belonging to many families, especially the Lamiaceae. Aside from this herbal ingredient, dozens of its natural derivatives have also been isolated and characterized from many natural plants. In recent years, with the increasing focus on the natural products as alternative treatments, a large number of pharmacological studies have been carried out to demonstrate the various biological activities of RA such as anti-inflammation, anti-oxidation, anti-diabetes, anti-virus, anti-tumor, neuroprotection, hepatoprotection, etc. In addition, investigations concerning its biosynthesis, extraction, analysis, clinical applications, and pharmacokinetics have also been performed. Although many achievements have been made in various research aspects, there still exist some problems or issues to be answered, especially its toxicity and bioavailability. Thus, we hope that in the case of natural products, the present review can not only provide a comprehensive understanding on RA covering its miscellaneous research fields, but also highlight some of the present issues and future perspectives worth investigating later, in order to help us utilize this polyphenolic acid more efficiently, widely, and safely.  相似文献   
865.
Microgels are extremely interfacially active and are widely used to stabilize emulsions. However, they are commonly used to stabilize oil-in-water emulsions due to their intrinsic hydrophilicity and initially dispersed in water. In addition, there have been no attempts to control microgel structural layers that are formed at the interface and as a result it limits applications of microgel in advanced materials. Here, we show that by introducing octanol into poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-MAA) microgels, octanol-swollen microgels can rapidly diffuse from the initially dispersed oil phase onto the water droplet surface. This facilitates the formation of microgel-laden interfacial layers with strong elastic responses and also generates stable inverse water-in-oil Pickering emulsions. These emulsions can be used as templates to produce microgel colloidosomes, herein termed ‘microgelsomes’, with shells that can be fine-tuned from a particle monolayer to a well-defined bilayer. The microgelsomes can then be used to encapsulate and/or anchor nanoparticles, proteins, vitamin C, bio-based nanocrystals or enzymes. Moreover, the programmed release of these substances can be achieved by using ethanol as a trigger to mediate shell permeability. Thus, these reconfigurable microgelsomes with a microgel-bilayer shell can respond to external stimuli and demonstrate tailored properties, which offers novel insights into microgels and promise wider application of Pickering emulsions stabilized by soft colloids.

Inverse W/O Pickering emulsions and reconfigurable microgelsomes with a well-defined bilayer structure are prepared from octanol-swollen PNIPAM-co-MAA microgels and the combination of binary microgels, which promise wider application of soft colloids.  相似文献   
866.
太空育种射干的X射线荧光及X射线衍射分析和表征   总被引:8,自引:3,他引:5  
联用X射线荧光光谱(XRF)和粉末X射线衍射(PXRD)方法,对我国独创的第4代太空诱变育种射干中多种元素种类和含量及晶态物质进行了研究。结果表明:太空组射干K元素含量比地面组、对照品分别提高了1.03和0.31倍,Mg元素分别提高了1.44和0.06倍,Ca,Mn和Fe元素含量比地面组分别提高了0.95,0.30和0.29倍,Al元素比地面组、对照组分别降低了38.5%和85.5%,并在射干中鉴别出一水草酸钙(CaC2O4.H2O)晶体,晶体含量是地面组<太空组<对照品。从而可得出结论:太空射干中人体必需的矿质元素比地面组都更接近或优于对照品。文章研究结果和方法对筛选品质优良的太空药材籽种和推广种植太空药材以及建立中药材质量评价标准,有积极的作用和重要意义。  相似文献   
867.
Semen descurainiae oil (SDO) is an important traditional Chinese medicine that was recently discovered to have the function of reducing blood lipids. Metabolomics analyses of plasma, liver and kidney in rats were performed using 1H‐NMR and LC–MS to illuminate the lower blood lipid concentration effect of SDO, and niacin was considered as the active control. The measure of total cholesterol (TC) and low‐density‐lipoprotein cholesterol (LDL‐C) in plasma showed that SDO treatment decreased significantly the content of TC and LDL‐C. An orthogonal partial least squares–discriminant analysis approach was applied to identify the different metabolic profiles of plasma, liver and kidney in rats and to detect related potential biomarkers. The results suggested that the metabolic profiles of the control group and hyperlipidemia group showed significant difference and the SDO and niacin group had effective anti‐hyperlipidemia function. The biomarkers primarily concern lipid metabolism, amino acid metabolism and glycometabolism, and the change in biomarkers indicated that hyperlipidemia could cause the unbalance of these metabolic pathways in vivo. SDO reduced blood lipids by repairing amino acid and lipid metabolism.  相似文献   
868.
Recently, the high-concentration phosphorus-containing wastewater has been caused lots of negative influences on aquatic environment and thus driven people to develop some effective methods to remove excess of phosphate in water. In order to solve these environmental problem, in this work, a tetraethylenepentamine (TEPA) modified 4A zeolite has been prepared and used for removing phosphate. Removal of phosphate by precipitation of 4A zeolite and electrostatic action of TEPA with phosphate were determined by scanning electron microscopy, X-ray powder diffraction and Fourier infrared spectrum, and morphology and characteristic peak of TEPA-4A zeolite before and after adsorption changed significantly. In addition, the results of batch adsorption studies showed that the pH of the solution have a significant influence on the adsorption of TEPA-4A and the biggest adsorption capacity was 23 mg/g at pH = 2.3 ± 0.2. Adsorption isotherms results showed that the process was consistent with Langmuir model and the maximum adsorption capacity could reach to 28 mg/g at 25 °C. TEPA-4A adsorption processes were spontaneous endothermic reaction, and elevated temperatures were conducive to the adsorption process through kinetics and thermodynamics results. The research of TEPA modified 4A zeolite and raw 4A zeolite provides technical support for the development of 4A zeolite instead of sodium tripolyphosphate as a new type of detergent ingredient.  相似文献   
869.
870.
Plasma free metanephrines (PFMs) have high sensitivity for detecting pheochromocytoma (PCC). Herein, we developed a simple and reliable liquid chromatography tandem mass spectrometry assay for PFMs determination in Chinese population. PFMs were enriched by SPE without requiring extract evaporation or the use of buffers containing nonvolatile salts. The analytes were analyzed in multiple reaction monitoring mode. Inter‐ and intra‐assay precisions were ≤4.3% and ≤ 6.3%. The lower limits of quantification were 0.07 nmol/L for metanephrine and 0.06 nmol/L for normetanephrine. Recoveries of PFMs were in the range of 89.3–113%. The method was free from significant matrix effect, carryover and interference. Owing to its fast analysis time, more than 150 samples/day could be easily performed by a single operator. With the established reference intervals of PFMs in the Chinese population, this simple and robust LC–MS/MS method could be valuable for use in routine clinical laboratories. It is noted that the combined tests of PFMs with urinary catecholamines or urinary vanillylmandelic acid could improve specificity.  相似文献   
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