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991.
992.
采用理论与实验相结合的方法对稀土多金属氧酸盐的发光性质进行探究。首先,通过常规水溶液法合成了一系列稀土多金属氧簇Na9LnW10O36 (Ln3+=Sm3+、Eu3+、Tb3+、Dy3+);其次,利用粉末X射线衍射、红外光谱、拉曼光谱对簇合物的结构进行表征;最后,利用紫外-可见光谱、荧光光谱对簇合物的光学性质进行考查。通过系统性的实验使学生对稀土簇合物的结构表征以及发光性质有全面、深刻的认识。  相似文献   
993.
夏越  杨从  段志欣 《大学化学》2020,35(9):185-193
基于准经典轨线方法和Matlab的GUI技术,我们开发设计了将a+bc三原子基元化学反应的碰撞过程可视化的动力学模拟程序,详细介绍了准经典轨线方法的基本原理、碰撞过程动力学信息的抽取和图形用户界面制作过程,并以典型反应F+HCl→Cl+HF为例展示了程序运行的结果。该程序可以将原子-双原子分子碰撞过程及碰撞的结果直观生动地通过动画的形式展现出来。学生也可以通过图形用户界面进行人机交互,从多个角度实时观察参与碰撞的原子、分子状态随时间的演化过程及结果。这有助于学生理解基元化学反应复杂的反应机理,加深对微观化学反应过程的感性认识。  相似文献   
994.
The synthesis and stimuli-responsiveness of a diphenyl cyclopropenone(DPCP)-centered poly(methyl acrylate)(PMA) are presented.DPCP-centered PMA could release carbon monoxide(CO) upon UV light in a switched on-and-off manner.The CO-releasing process can be reported by the variations in photoluminescence spectra.In addition,DPCP moiety covalently embedded in the crosslinked polyurethane could also release CO under UV light.Of special,DPCP-centered PMA in solution was selectively dissociated at the...  相似文献   
995.
Main observation and conclusion With the rapid development of the wearable electronics,the flexible supercapacitor with high energy density has attracted more a...  相似文献   
996.
提出了一种将结构支撑位置和支撑类型作为设计变量的优化设计方法,就支撑条件改变对结构受力的影响进行了分析,论述了如何在遗传算法中实现结构支撑位置和支撑类型的优化,并通过数值算例说明了结构支撑条件的转变对结构的影响,证明结构支撑条件的优化处理对提高结构性能是有效的.  相似文献   
997.
998.
Safflower has both medicinal and edible values but research on its nutrient composition is still lacking. This study was established for the quantitative determination of 28 nucleosides, nucleobases, and amino acids based on the ultra‐performance liquid chromatography coupled with triple‐quadrupole linear ion‐trap tandem mass spectrometry. Analysis of 30 batches of safflower from different producing areas indicated that the contents of l ‐proline, l ‐asparagine, l (+)‐arginine, l ‐serine, l ‐histidine, uracil, guanosine, and uridine was high in safflower. Principle component analysis and cluster analysis found that samples from different regions could be distinguished well, and samples from the same area could be clustered into one class, different geographical environments may cause the differences of nucleosides, nucleobases, and amino acids in safflower. The analysis of principal component analysis, cluster analysis, and counter propagation artificial neural network show similar results. Then the content of nucleosides, nucleobases, and essential amino acids were compared, and found that the content in safflower from Gansu was higher than those from other regions, and there was a little difference between the samples from Xinjiang, Sichuan, and Yunnan. This research revealed the composition of nucleosides, nucleobases, and amino acids in safflower, and provided a theoretical basis for utilization of safflower.  相似文献   
999.
Prostate-specific membrane antigen (PSMA) is a well-established biological target that is overexpressed on the surface of prostate cancer lesions. Radionuclide-labeled small-molecule PSMA inhibitors have been shown to be promising PSMA-specific agents for the diagnosis and therapy of prostate cancer. In this study, a glutamate-urea-based PSMA-targeted ligand containing an isonitrile (CNGU) was synthesized and labeled with 99mTc to prepare [99mTc]Tc-CNGU with a high radiochemical purity (RCP). The CNGU ligand showed a high affinity toward PSMA (Ki value is 8.79 nM) in LNCaP cells. The [99mTc]Tc-CNGU exhibited a good stability in vitro and hydrophilicity (log P = −1.97 ± 0.03). In biodistribution studies, BALB/c nude mice bearing LNCaP xenografts showed that the complex had a high tumor uptake with 4.86 ± 1.19% ID/g, which decreased to 1.74 ± 0.90% ID/g after a pre-injection of the selective PSMA inhibitor ZJ-43, suggesting that it was a PSMA-specific agent. Micro-SPECT imaging demonstrated that the [99mTc]Tc-CNGU had a tumor uptake and that the uptake was reduced in the image after blocking with ZJ-43, further confirming its PSMA specificity. All of the results in this work indicated that [99mTc]Tc-CNGU is a promising PSMA-specific tracer for the imaging of prostate cancer.  相似文献   
1000.
Atomic regulation of metal catalysts has emerged as an intriguing yet challenging strategy to boost product selectivity. Here, we report a density functional theory-guided atomic design strategy for the fabrication of a NiGa intermetallic catalyst with completely isolated Ni sites to optimize acetylene semi-hydrogenation processes. Such Ni sites show not only preferential acetylene π-adsorption, but also enhanced ethylene desorption. The characteristics of the Ni sites are confirmed by multiple characterization techniques, including aberration-corrected high-resolution scanning transmission electron microscopy and X-ray absorption spectrometry measurements. The superior performance is also confirmed experimentally against a Ni5Ga3 intermetallic catalyst with partially isolated Ni sites and against a Ni catalyst with multi-atomic ensemble Ni sites. Accordingly, the NiGa intermetallic catalyst with the completely isolated Ni sites shows significantly enhanced selectivity to ethylene and suppressed coke formation.  相似文献   
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