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461.
462.
为了实现结构色涂层在纸张表面的快速制备,研究不同组装条件对SiO2结构色涂层呈色效果的影响,采用快速涂布的方法,在纸张表面制备出了大面积且具有随角异色特性的结构色涂层。探讨SiO2微球粒径、分散液浓度及涂布次数等因素对结构色涂层光学特性的影响,通过优化自组装条件和分析周期性结构构筑类型,阐明快速涂布法构建的SiO2微球在激光打标纸上的自组装过程及结构色呈色机理。应用数码相机、3D激光共聚焦形貌测量显微镜等仪器对样品的颜色外观和微观结构进行测量,表征样品的呈色性能及表面结构。使用X-Rite MA68Ⅱ多角度分光光度仪及光纤光谱仪测量反射光谱,进而用CIEL*a*b*色度值对制备的结构色涂层的光学性能进行分析。结果表明,通过快速涂布自组装法制备所得的结构色涂层,SiO2微球粒径尺度对样品色调影响显著,随着微球粒径的增加,反射光谱中心波长发生红移,且该涂层有角度依赖特性,当固定入射角度为45°时,随着探测方向与镜面反射方向夹角的增大,中心波长发生红移;微球溶液的浓度可以调控结构色涂层反射光谱曲线的半高宽及反射率峰值,进而影响样品的亮度和彩度,而对于光子带隙的位置无明显影响。微球浓度为4%时,样品表面呈现出基材本身的黑色,微球浓度为8%时,200,220和250 nm粒径的样品表面分别可以呈现彩度较低的蓝色、绿色、黄色,微球浓度增加到10%时,纸张表面的结构色涂层彩度提高,色调不变;随着涂布次数的增加,反射光谱曲线的半高宽变窄,且反射峰位发生蓝移,涂布次数达到3次时,反射峰位最接近于根据布拉格定律计算出的理论值,但涂布次数的增加也使得结构色涂层表面产生白色的不均匀现象。 相似文献
463.
研究四君子汤在2型糖尿病大鼠体内的药代动力学。 将四君子汤水提物以18 g/kg给正常大鼠和2型糖尿病大鼠灌胃,分别在不同时间点取尿液和粪便,检测其成分及代谢产物的含量;比较正常大鼠和2型糖尿病大鼠的药代动力学参数。 采用快速高分辨液相色谱-质谱联用技术对人参皂苷Rc、甘草甜素及其脱糖代谢物进行表征。 结果表明,四君子汤中人参皂苷Rc和甘草甜素在2型糖尿病大鼠体内的累计排泄率均高于正常大鼠,大部分人参皂苷通过尿液排出体外、粪便代谢为稀有人参皂苷;大部分甘草甜素在尿液和粪便中转化为甘草次酸,2型糖尿病大鼠与正常大鼠人参皂苷Rc和甘草甜素的药代动力学参数存在明显差异。 初步总结了四君子汤在体内的药代动力学机制和代谢途径。本分析方法具有高度自动化,灵敏性和准确性,这将有助于四君子汤的临床研究的不断发展。 相似文献
464.
Tomoya Yoshinari Hiroyuki Ohashi Ryoji Abe Rena Kaigome Hideo Ohkawa Yoshiko Sugita-Konishi 《Analytica chimica acta》2015
Quenchbody (Q-body) is a novel fluorescent biosensor based on the antigen-dependent removal of a quenching effect on a fluorophore attached to antibody domains. In order to develop a method using Q-body for the quantitative determination of deoxynivalenol (DON), a trichothecene mycotoxin produced by some Fusarium species, anti-DON Q-body was synthesized from the sequence information of a monoclonal antibody specific to DON. When the purified anti-DON Q-body was mixed with DON, a dose-dependent increase in the fluorescence intensity was observed and the detection range was between 0.0003 and 3 mg L−1. The coefficients of variation were 7.9% at 0.003 mg L−1, 5.0% at 0.03 mg L−1 and 13.7% at 0.3 mg L−1, respectively. The limit of detection was 0.006 mg L−1 for DON in wheat. The Q-body showed an antigen-dependent fluorescence enhancement even in the presence of wheat extracts. To validate the analytical method using Q-body, a spike-and-recovery experiment was performed using four spiked wheat samples. The recoveries were in the range of 94.9–100.2%. The concentrations of DON in twenty-one naturally contaminated wheat samples were quantitated by the Q-body method, LC-MS/MS and an immunochromatographic assay kit. The LC-MS/MS analysis showed that the levels of DON contamination in the samples were between 0.001 and 2.68 mg kg−1. The concentrations of DON quantitated by LC-MS/MS were more strongly correlated with those using the Q-body method (R2 = 0.9760) than the immunochromatographic assay kit (R2 = 0.8824). These data indicate that the Q-body system for the determination of DON in wheat samples was successfully developed and Q-body is expected to have a range of applications in the field of food safety. 相似文献
465.
Rapid extraction and analysis method for the simultaneous determination of 21 bioflavonoids in Siegesbeckia pubescens Makino
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Yaqi Yao Xiao Liang Xiaoqi Sun Lina Yin Hai He Xingjie Guo Zhen Jiang 《Journal of separation science》2015,38(7):1130-1136
A novel and rapid microwave extraction and ultra high performance liquid chromatography coupled with a triple quadrupole‐linear ion trap mass spectrometry method was developed and validated for the determination of 21 bioflavonoids in Siegesbeckia pubescens Makino. The optimal conditions for the extraction of flavonoids from Siegesbeckia pubescens Makino involved the use of methanol as the extraction solvent, a microwave temperature of 70°C, an extraction time of 11 min, and a solvent‐to‐solid ratio of 40 mL/g. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C18 column(100 × 2.1 mm, 1.7 μm) with a gradient mobile phase (A: 0.3% v/v aqueous formic acid and B: acetonitrile) at a flow rate of 0.25 mL/min. All calibration curves showed good linearity (r > 0.999) within the test ranges. The method developed was validated with acceptable sensitivity, intra‐ and interday precision, reproducibility, and extraction recoveries. The validated method was successfully applied to determine the contents of 21 bioflavonoids in Siegesbeckia pubescens Makino from different sources. 相似文献
466.
Compacts of 7075 aluminum have been produced from rapidly solidified powders by optimizing spark sintering parameters, such as pulse discharge time, fixed maximum temperature, holding time at this temperature, and method of cooling to room temperature after the sintering. High-grade compacts can be obtained by a short process (40-50 s) consisting of heating to 773 or 873 K at a heating rate of 9.6 K/s and holding this temperature for 10 s. The rapidly cooled compacts show the same supersaturated state at room temperature as the received as-atomized powder. Compacts quenched in water just after spark sintering at 873 K for 1.2 ks show the same age-hardening behavior as solution-heat treated compacts. Compacts that are quenched in water and aged after sintering at 873 K for 1.2 ks show the same elongation and flow stress as compacts aged after solution heat treatment. Elongation data suggest that compacts produced with longer holding time at a higher temperature and rapid cooling show a large amount of main alloying elements in solid solution and sufficient promotion of sintering. 相似文献
467.
468.
利用液相色谱-质谱联用法对小儿肺炎( Childhood pneumonia, CP)患者和健康儿童( Healthy control)的尿液进行分析,发现小儿肺炎患者尿液中的潜在标记物,为其发病机制及早期筛查提供科学依据。筛选10例小儿肺炎患者(age 47.72±2.35 months)及10例健康儿童(age 46.65±1.97 months)尿液样本,采用快速高分辨液相色谱四极杆-飞行时间质谱联用( RRLC-Q TOF/MS)技术对其尿液代谢物进行分析,通过主成分分析方法( PCA)对两组代谢物进行分类,并发现潜在生物标记物。 RRLC-Q TOF/MS检测表明,CP组和Healthy Control组尿液代谢物图谱能得到很好的区分,并鉴定了5种生物标记物,提示嘌呤代谢、氨基酸代谢可能在小儿肺炎发生发展中有重要作用。 相似文献
469.
介绍了一种车载大功率DC/DC电源变换器(以下简称DC/DC)的测试方法,运用V模式理念并结合半实物仿真验证测试方法对DC/DC的技术方案进行了全数字仿真验证测试、对DC/DC的控制电路部分进行了快速控制原型仿真验证测试、对DC/DC的功率电路部分进行了硬件在环仿真验证测试、对集成功率及控制电路的DC/DC进行了功率硬件在环验证测试,并根据测试结果又进行了迭代验证测试。通过半实物验证测试,对DC/DC各项设计参数的正确性及性能指标符合性进行验证测试,保证DC/DC技术方案的合理可行。 相似文献
470.
刘伟 《理化检验(化学分册)》2008,44(2):134-136
采用对样品进行液氮淬火及溴化处理的制样方法,以期达到消除分子晶体场及分子链烯类端基对分析谱带的影响和干扰,结果表明:(1) 1 378 cm-1甲基对称变形振动谱带强而尖锐,和1 368 cm-1亚甲基面外摇摆振动谱带清晰分开,表明分子链上只存在一种单一的支链;(2)890 cm-1附近不存在表征长支链的甲基面内摇摆振动峰,只有772 cm-1附近存在表征乙基支链的亚甲基面内摇摆振动峰.成功地鉴定了以1-丁烯为共聚单体的线型低密度聚乙烯,方法简便、快速,为鉴定其他类的以烯烃为共聚单体的线型低密度聚乙烯(LLDPE)提供了重要思路. 相似文献