白簕叶总黄酮的提取和纯化及其抑菌试验初探

观察白簕叶中总黄酮的抑菌作用。采用微波辅助法从白簕叶中提取黄酮化合物,经HPD-600型树脂纯化,通过圆形滤纸片法和二倍稀释法分别对黄酮提取液进行了抑菌试验和最小抑菌浓度(MIC)的测定。HPD-600型树脂纯化后的黄酮纯度达到21.3%,对3种供试菌的抑菌作用为大肠杆菌金色葡萄球菌芽孢杆菌,随着总黄酮浓度的增加,其抑菌作用也增强。白簕叶总黄酮对大肠杆菌、金色葡萄球菌、和芽孢杆菌的MIC分别为原液的1/4、1/2倍和1倍。本方法为白簕的药用价值开发开辟了新途径。     

Decreasing the shell ratio of core-shell type nanoparticles with a ceria core and polymer shell by acid treatment

Core-shell type nanoparticles with a ceria core and polymer shell have good dispersibility. Some applications, such as fillers for increasing the refractive index and/or protecting resin films from ultraviolet (UV) light, i.e., UV cutting, require a smaller shell. Previous studies have decreased the shell weight by heat treatment in gas; however, the dispersibility of the treated nanoparticles was poor in water or alcohol. In this study, we investigated the efficacy of acid treatment for decreasing the shell weight and also evaluated the dispersibility of acid-treated nanoparticles. The thus-formed nanoparticles treated by acetic acid and formic acid show not only good dispersibility but also a well decreased shell thickness. The structure of the shell after acetic acid treatment was found to be the same as that of the untreated core-shell nanoparticles; moreover, acetic acid was present in the shell. Furthermore, by using the acetic-acid-treated nanoparticles, a transparent resin film without nanoparticle aggregation could be obtained.     

Ambient Preparation of Benzoxazine-based Phenolic Resins Enables Long-term Sustainable Photosynthesis of Hydrogen Peroxide

Rational design of polymer structures at the molecular level promotes the iteration of high-performance photocatalyst for sustainable photocatalytic hydrogen peroxide (H₂O₂) production from oxygen and water, which also lays the basis for revealing the reaction mechanism. Here we report a benzoxazine-based m-aminophenol-formaldehyde resin (APFac) polymerized at ambient conditions, exhibiting superior H₂O₂ yield and long-term stability to most polymeric photocatalysts. Benzoxazine structure was identified as the crucial photocatalytic active segment in APFac. Favorable adsorption of oxygen/intermediates on benzoxazine structure and commendable product selectivity accelerated the reaction kinetically in stepwise single-electron oxygen reduction reaction. The proposed benzoxazine-based phenolic resin provides the possibility of production in batches and industrial application, and sheds light on the de novo design and analysis of metal-free polymeric photocatalysts.     

A Janus Separator based on Cation Exchange Resin and Fe Nanoparticles-decorated Single-wall Carbon Nanotubes with Triply Synergistic Effects for High-areal Capacity Zn−I2 Batteries

Zn−I₂ batteries stand out in the family of aqueous Zn-metal batteries (AZMBs) due to their low-cost and immanent safety. However, Zn dendrite growth, polyiodide shuttle effect and sluggish I₂ redox kinetics result in dramatically capacity decay of Zn−I₂ batteries. Herein, a Janus separator composed of functional layers on anode/cathode sides is designed to resolve these issues simultaneously. The cathode layer of Fe nanoparticles-decorated single-wall carbon nanotubes can effectively anchor polyiodide and catalyze the redox kinetics of iodine species, while the anode layer of cation exchange resin rich in −SO₃⁻ groups is beneficial to attract Zn²⁺ ions and repel detrimental SO₄²⁻/polyiodide, improving the stability of cathode/anode interfaces synergistically. Consequently, the Janus separator endows outstanding cycling stability of symmetrical cells and high-areal-capacity Zn−I₂ batteries with a lifespan over 2500 h and a high-areal capacity of 3.6 mAh cm⁻².     

红外光谱法原位监测亚微米树脂吸附反应

亚微米树脂吸附反应是一种快速反应,离线取样分析较困难。本文采用红外光谱技术原位监测亚微米树脂吸附庆大霉素反应,找到并验证了脂上吸附庆大霉素的吸收峰位置,并用偏最小二乘法建立定量模,模型的相关系数为０．９７９。在此基础上对不同初始浓度的吸附反应实现了原位监测。     

3种菊花茶中6种微量元素的初级形态及溶出特性研究

按照传统的花茶饮用方法对杭白菊茶、野菊花茶、贡菊茶3种菊花茶中钙、镁、铁、锰、铜、锌6种元素进行浸取;用0.45μm微孔滤膜分离浸取液中的可溶态和悬浮态;采用电感耦合等离子体原子发射光谱法对此3种菊花茶中微量元素的初级形态进行了测定。结果显示：菊花茶中6种元素的提取率在12.4%—80.4%之间,可溶态在水浸液中的比率在74.3%—96.5%之间。     

流动注射双光束光度法测定大黄中黄素含量

用改进的流动注射光度法测定大黄中黄素含量。大黄素在碱性介质中生成稳定红色络合物的特性,最大吸收波长为λ=530nm,一次进样同时产生一正一负两拐点的响应曲线。利用△A（A1—A2）的微分光度值进行定量分析,进样频率为130次·h^-1,线性范围为1.5-350μg·mL^-1,相关系数r=0.9997,相对标准偏差RSD=0.97%（n=9）。方法操作简单,快速可靠,平均回收率为99.6%。     

强碱性阴离子交换树脂分离富集土壤中的钼

研究了以强碱性阴离子交换树脂为固定相的离子交换色谱法分离富集土壤中钼,实现了钼与其他常见金属元素离子的选择性分离,富集在色谱柱上的钼以0.5mol.L^-1NH4NO3＋2mol.L^-1HNO3洗脱并用富氧火焰原子吸收光谱法进行测定,钼的回收率为99%—101.3%。     

基于特征点及优化理论的图像自动拼接方法

提出了一种新的图像拼接方法,首先利用相位一致性(phase congruency)算法进行特征点检测,利用本文提出的匹配点优选策略进行特征点对自动选取,然后用LM(Levenberg-Marquardt)算法进一步优化变换矩阵,最后对拼接结果进行融合处理,获得无缝拼接的图像.该方法把基于特征点和基于优化理论的拼接方法有效相结合,且能充分利用图像重叠部分的信息,在一定程度上克服了噪声及光照不均的影响,较传统方法具有更强的鲁棒性和更高的拼接精确度.试验结果证明了该方法的有效性.     

ICP-AES同时测定水产品中的稀土元素

研究了 P50 7萃淋树脂预富集分离样品 ,试液用 ICP- AES法同时测定水产品中稀土元素 La、Sm、Y、Nd的新方法。在选定的最佳条件下测 La、Sm、Y、Nd的检出限分别为 0 .0 0 5 2、0 .0 0 70、0 .0 0 93、0 .0 16 1μg·m L-1,回收率为 93.4 %— 10 2 .5 % ,RSD为 1.3%— 3.6 %。该法准确、快速、简便 ,应用于水产品的测定 ,结果满意