低氯甜菜碱的制备(英文)

本文报道了一种低氯甜菜碱的制备方法。通过将甜菜碱粗品分别与无机酸如硫酸、盐酸和磷酸成盐后再加碱精制甜菜碱,经离子色谱测定,磷酸盐甜菜碱精制所得甜菜碱氯离子含量由市售的2%降低到0.02%左右,产品质量可很好满足化妆品行业的要求。     

Effect of initial-state target polarization on the single ionization of helium by l-keV electron impact

We report new results of triple differential cross sections for the single ionization of helium by 1-KeV electron impact at the ejection energy of 10 eV. Investigations have been made for both the perpendicular plane and the plane perpendicular to the momentum transfer geometries. The present calculation is based on the threewCoulomb wave function. Here we have also incorporated the effect of target polarization in the initial state. A comparison is made between the present calculation with the results of other theoretical methods and a recent experiment [Diirr M, Dimopoulou C, Najjari B, Dorn A, Bartschat K, Bray I, Fursa D V, Chen Z, Madison D H and Ullrich J 2008 Phys. Rev. A 77 032717]. At an impact energy of 1 KeV, the target polarization is found to induce a substantial change of the cross section for the ionization process. We observe that the effect of target polarization plays a dominant role in deciding the shape of triple differential cross sections.     

Surface Changes of Ochrobactrum Anthropi in Cr（Ⅵ） Treatment for 1 Hour

Bioremediation has been a considerable method for treating Cr（VI） contamination. Bacterial surface changes of Ochrobactrum anthropi during Cr biosorption was investigated in this study. We found that Cr adsorption capacity increased with the increase of initial Cr（Ⅵ） concentration. Atomic force microscope （AFM） morphologic analysis combined with surface roughness analysis indicated that the bacterial surfaces became rougher during Cr uptake process. X-ray photoelectron spectroscopy （XPS） showed that Cr（Ⅲ） was adsorbed on the bacterial surfaces. Fourier transform infrared （FT-IR） analysis showed that surface functional groups including C-O and C-N might be involved in the Cr biosorption process.     

莫西沙星及其杂质的合成研究进展

莫西沙星是第四代喹诺酮类抗菌药物,具有抗菌谱广、抗菌活性强、低毒等特点,因此在临床上得到了广泛的应用。莫西沙星在生产、储存过程中容易产生杂质,为了确保临床用药安全有效,莫西沙星的杂质需要进行控制。本文主要对莫西沙星及其杂质的合成研究进展进行综述。     

氧氮共掺杂石墨烯光催化降解高浓度亚甲基蓝性能研究

本文采用原位合成法及混酸氧化法制备氧氮共掺杂石墨烯(ONG).通过透射电子显微镜分析(TEM)、X射线能谱分析(XPS)、紫外可见光漫反射(UV-vis DRS)、光致发光光谱(PL)等测试方法对所制得催化剂进行了表征,并以亚甲基蓝为目标降解物探究了材料的光催化活性及降解机理.结果表明:混酸氧化法制备的氧氮共掺杂石墨烯...     

Single- and Double-Electron Capture Processes in Low-Energy Collisions of N~(4+) Ions with He

We investigate the electron capture processes of N⁴⁺(1s²2s) colliding with He(1s²) in the energy range of 10-1700 eV/amu using the quantum-mechanical molecular-orbital close-coupling(QMOCC) method.Total and stateselective single-electron capture and double-electron capture(SEC and DEC) cross sections are obtained and compared with other available studies.The results agree better with the experimental data in both trend and magnitude when the electron translation ...     

Electron excitation processes in low energy collisions of hydrogen-helium atoms

The electron excitation processes of $\rm H(1s) + He(1s^{2}) \to H(2s/2p) + He(1s^{2})$ are studied in impact energy range of 20—2000 eV/u by using the quantum-mechanical molecular orbital close-coupling (QMOCC) method. Total and state-selective cross sections have been obtained and compared with the available theoretical and experimental results. The results agree well with available measurements in the overlapping energy regions overall. The comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of channels. The datasets presented in this paper, including the excitation cross sections, are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00083.     

负载金属催化剂Ir(γ-Al2O3)对阿维菌素选择加氢反应研究

分别采用氢气、NaBH₄、醇水混合溶剂还原, PVP(聚乙烯吡咯烷酮)保护和微乳液法制备了γ-Al₂O₃负载的Ir金属催化剂, 通过XPS、XRD、TEM对催化剂的结构进行了表征, 考察了催化剂对阿维菌素选择加氢制备伊维菌素的性能, 探讨了催化剂制备方法对催化剂活性和选择性的影响. 实验结果表明, 在不同金属催化剂Ru/γ-Al₂O₃、Pd/γ-Al₂O₃、Pt/γ-Al₂O₃、Ir/γ-Al₂O₃中, Ir/γ-Al₂O₃的活性和选择性最好. 用PVP保护的Ir/γ-Al₂O₃, 其催化活性和选择性比没有PVP保护的催化剂有显著提高; 采用微乳液法制备的Ir/γ-Al₂O₃催化剂显示出最好的活性, 但反应选择性比PVP保护的催化剂差.     

基于金纳米颗粒的比色传感体系用于前列腺特异性膜抗原的检测

发展了一种基于金纳米颗粒的比色传感体系用于检测前列腺特异性膜抗原的新方法.实验中合成了带有正电荷的金纳米颗粒,并设计了一段带有负电荷的前列腺特异性膜抗原的底物肽段.该方法基于金纳米颗粒聚集状态不同导致颜色变化的性质以及酶与底物的特异性识别作用,达到前列腺特异性膜抗原的检测.带正电荷的金纳米颗粒与带负电的肽段产生静电相互作用,引起金纳米颗粒的聚集;当体系中加入前列腺特异性膜抗原后,由于前列腺特异性膜抗原与肽段的特异性识别作用,带负电的肽段水解为谷氨酸碎片分子,导致金纳米颗粒的分散,反应体系颜色变化快速、明显.该方法简单、灵敏,线性范围为2～10 nmol/L,检测限为0.5 nmol/L.此外,该方法可用于标准加入法测定尿液中的PSMA.     

近红外光谱技术在天然草地植被管理中的应用

植被是监测草地健康和生产力的主要依据,其变化是草地生态系统退化和恢复状况的最直接体现。及时掌握草地植被的变化信息是防止草地退化、实现草地生态系统可持续发展的首要条件。近红外光谱技术以其简便、快捷等优越性广泛应用于不同领域,在草地资源管理中有巨大的应用潜力和前景。文章介绍了近红外光谱技术的原理、特点及其在草地植被物种组成、草地植物茎叶比、凋落物及牧草品质测定等方面的应用特点,综合阐述了近红外光谱技术在草地植被管理中的应用现状,并对其应用前景进行了展望。