共查询到20条相似文献,搜索用时 62 毫秒
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采用磷化铝粮面施药,利用大气湿度自然潮解、环流熏蒸,不仅经济、安全、有效,解决了环流熏蒸施药时间长,投药量少的问题,而且浓度均匀,杀虫效果好. 相似文献
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通过对5-u聚乳酸载药微球接PEI进行表面胺解、接枝靶向基团Folate以及荧光物质FITC,制备了靶向5-u聚乳酸微球,并研究了微球的缓释性能、荧光效应和主动靶向性.结果表明,靶向5-u聚乳酸微球具有良好的缓释性能,缓释时间可达到105h;未改性的载药微球对Hela细胞的抑制作用有限,无主动靶向性:改性的载药微球具有明显的荧光效应和良好的主动靶向性. 相似文献
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硼酸盐具有抑菌和抑藻性能, 研究采用高温熔融法合成了以硼为抑菌因子的B2O3-SiO2-Na2O缓释抑菌剂。运用X射线衍射分析(XRD)、扫描电镜(SEM)及红外光谱(FTIR)表征抑菌剂的理化性能, 采用电感耦合等离子体发射光谱仪(ICP-AES)测定缓释液中硼元素的浓度并分析抑菌剂的缓释特性, 分别以大肠杆菌和金黄色葡萄球菌为受试细菌, 以抑菌圈和抑菌率为指标评价药剂的抑菌效果。结果表明, 抑菌剂均呈无定形非晶形态, 内部[BO3]和[BO4]基团的含量不只与B2O3有关, 也受SiO2的影响; 随着B2O3含量的降低, 抑菌剂表面结构逐渐致密, 缓释速率降低。随着缓释液中硼浓度的升高, 抑菌剂的抑菌作用增强, 且对金黄色葡萄球菌的抑制效果优于大肠杆菌。其中B2O3含量为55wt%的B2O3-SiO2-Na2O缓释抑菌剂的抑菌效果最佳, 这为硼系缓释抑菌剂的继续研究及工业化应用提供了参考依据。 相似文献
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采用球状活性炭作为硝苯地平药物载体,借助N2吸附仪表征了球状活性炭的比表面积和孔结构,利用SEM表征了球状活性炭的表面形貌,通过考察球状活性炭比表面积、孔隙结构与吸附性能和体外释放性能的关系,研究了球状活性炭对硝苯地平的吸附及缓释行为。结果表明:比表面积大、孔隙结构发达、孔径分布集中在2nm~5nm之间的中孔型活性炭,对硝苯地平的吸附能力较强,吸附量可达19.5mg/g;所制缓释微丸缓释效果良好,在接近人体胃液介质中累计释放率达到19.2%;球状活性炭对硝苯地平的释放动力学符合Higuchi模型,药物基本以恒定速率主动释放。 相似文献
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A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling. 相似文献
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An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a
rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate
agreement is demonstrated between the derived relations and experimental data. 相似文献
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Liebert A Wabnitz H Grosenick D Möller M Macdonald R Rinneberg H 《Applied optics》2003,42(28):5785-5792
A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue. 相似文献
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水三相点是开尔文热力学温度的唯一基准点,也是ITS-90国际温标重要的定义固定点。因此,水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来,中国计量科学研究院研制出一系列高质量的水三相点容器,加强了水三相点的研究,为不确定度的分析提供了更为可靠的实验依据。同时,不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此,根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明,其扩展不确定度为0.16mK(k=2.69,P=0.99)。 相似文献
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