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991.
Wenbo Huang Liqiao Shi Manli Liu Zhigang Zhang Fang Liu Tong Long Shaohua Wen Daye Huang Kaimei Wang Ronghua Zhou Wei Fang Hongtao Hu Shaoyong Ke 《Molecules (Basel, Switzerland)》2022,27(5)
Primary arylsulfonamide functional groups feature prominently in diverse pharmaceuticals. However, natural arylsulfonamides are relatively infrequent. In this work, two novel arylsulfonamide natural products were first synthesized, and then a series of novel molecules derived from natural arylsulfonamides were designed and synthesized, and their in vitro cytotoxic activities against A875, HepG2, and MARC145 cell lines were systematically evaluated. The results indicate that some of these arylsulfonamide derivatives exhibit significantly good cytotoxic activity against the tested cell lines compared with the control 5-fluorouracil (5-FU), such as compounds 10l, 10p, 10q, and 10r. In particular, the potential molecule 10q, containing a carbazole moiety, exhibited the highest inhibitory activity against all tested cell lines, with IC50 values of 4.19 ± 0.78, 3.55 ± 0.63, and 2.95 ± 0.78 μg/mL, respectively. This will offer the potential to discover novel drug-like compounds from the sparsely populated area of natural products that can lead to effective anticancer agents. 相似文献
992.
应用sol-gel浸渍与热处理工艺相结合,在活性炭表面包覆Sb掺杂的SnO2薄膜对电极进行修饰,构成AC-SnO2/KOH/AC-SnO2双电层电容器,测试结果表明,400 mA/g电流密度条件下,修饰后的双电层电容器在0.001~1.5 V相对较高电压区间的放电容量,比AC/KOH/AC双电层电容器在0.001~1.0 V电压区间高36%,但AC-SnO2的单电极比电容仅为AC单电极比电容的91.9%;当电流密度大于400 mA/g,两种电极的大电流性能相当。 相似文献
993.
该文提出了一种Gabor小波域的概率子空间人脸识别方法,简称GPSA方法。考虑到Gabor小波在人脸识别中的优势,首先给出了一种改进的人脸图像Gabor特征描述方法,在此基础上建立基于Gabor特征的概率子空间模型,人脸识别按照概率匹配方式进行,从而有机集成了Gabor特征描述和基于类内、类间变化的概率子空间分析两者所提供的鉴别信息,增强了人脸识别系统的鲁棒性。在包括190人的人脸数据库上的实验结果表明,所提出方法的识别性能较现有的概率子空间分析方法有了较明显的改善。 相似文献
994.
995.
Shi Shuangning Shang Yong Liang Qinglin Liang Bin 《电子科学学刊(英文版)》2007,24(6):812-814
The real Direction Of Arrival (DOA) varies with time in mobile communication system. In such situation, the performance of conventional beamformers will be degraded obviously. Quantum Signal Processing (QSP) beamformer is insensitive to DOA errors, thus it can achieve stable output performance in such circumstance. This letter verified the effectiveness and feasibility of the QSP beamformer by simulation results. 相似文献
996.
长拖尾K分布杂波下雷达目标散射中心参数的稳健估计 总被引:1,自引:0,他引:1
实际条件下,在对基于衰减指数(DE)和模型的雷达目标散射中心参数估计和特征提取时,其噪声背景往往是非高斯的,分布密度函数表现出长拖尾性质。利用基于高斯假设条件下的估计方法进行参数估计时,往往不能得到较好的结果。针对这种情况,该文利用M估计方法来实现对长拖尾杂波下DE模型参数的稳健估计。首先分析了基于PRONY模型的M估计实现方法存在的不足,其次提出了两种较为有效的DE模型散射中心参数M估计的实现方法,并对这两种方法进行了分析和比较。仿真实验结果表明,在一类长拖尾K分布杂波条件下,与ESPRIT方法以及扩展PRONY估计方法相比,该文所提的两种方法均能得到较好的估计结果。 相似文献
997.
建立了高温液相色谱系统,在高温条件下,采用甲醇-水作为流动相,在Polymerx RP-1聚合物(PSDVB)色谱柱上考察了6种酚类样品的色谱行为.实验条件:温度40~160 ℃,流速0.2~5.5 mL/min,流动相中甲醇浓度范围40%~80%.考察了温度、流速和流动相组成对酚类样品的保留、分辨、柱效和系统压力的影响,探讨了酚类样品在聚合物柱上的热力学行为.温度升高2.35℃大约相当于流动相中甲醇浓度增加1%,可以通过改变色谱柱温度调节样品保留和改变选择性.柱温升高,降低了流动相的粘度,允许在高温条件下使用较高的流速实现快速分离.在160℃、V(甲醇):V(水)=40:60,为流动相和3 mL/min流速条件下,可于2.5 min内实现6种酚类的完全分离. 相似文献
998.
Diffraction efficiency of grating plays an important role in output power of incoherent fiber laser beam combination. Through theoretic analysis and numerical simulations it has been proved that the diffraction efficiency would increase with the decrease of grating frequency and wavelength bandwidth. On the condition that the width of a fiber array is fixed at W=10 cm, an optimum grating frequency were numerically simulated as f=230 mm-1. Also an unequal interval method was proposed to improve the system efficiency of diffraction into 0.4293, which is higher than 0.3824 under the equal interval condition. 相似文献
999.
Yibo Li Lingxiao Zhao Laiquan Shi Lingshang Lin Qinghe Cao Cunxu Wei 《Molecules (Basel, Switzerland)》2022,27(6)
Sweet potato is a root tuber crop and an important starch source. There are hundreds of sweet potato varieties planted widely in the world. Starches from varieties with different genotype types and originating from different countries have not been compared for their physicochemical properties. In the research, starches from 44 sweet potato varieties originating from 15 countries but planted in the same growing conditions were investigated for their physicochemical properties to reveal the similarities and differences in varieties. The results showed that the 44 starches had granule size (D[4,3]) from 8.01 to 15.30 μm. Starches had different iodine absorption properties with OD680 from 0.259 to 0.382 and OD620/550 from 1.142 to 1.237. The 44 starches had apparent amylose content from 19.2% to 29.2% and true amylose content from 14.2% to 20.2%. The starches exhibited A-, CA-, CC-, or CB-type X-ray diffraction patterns. The thermograms of 44 starches exhibited one-, two-, or three-peak curves, leading to a significantly different gelatinization temperature range from 13.1 to 29.2 °C. The significantly different starch properties divide the 44 sweet potato varieties into different groups due to their different genotype backgrounds. The research offers references for the utilization of sweet potato germplasm. 相似文献
1000.
用于显示的透射型法布里-珀罗光调制器 总被引:2,自引:2,他引:0
提出了一种用于显示的,基于透射型法布里-珀罗干涉的微机电系统(MEMS)光学调制器。基于多光束干涉原理分析了调制器的光学特性,推导出了调制器结构的特征参量。分析表明,当调制器的腔长为cλ/4时,透射光可以实现暗态显示;当调制器的腔长取为零或cλ/2时,透射光可以实现亮态显示。通过控制法布里-珀罗腔长,就可实现调制器的明暗调制。理论上证明了该调制器用于显示的可行性。设计了一种基于微机电系统的透射型法布里-珀罗光学调制器结构,该调制器的理论衬比度达到150。仿真结果表明,该调制器具有2.4 V的低电压静电驱动性能。 相似文献