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991.
Wenjing Li Caihong Li Kang Sun Chenglin Chi Zongchao Li Lixiao Xu Yan Zhao Rongxia Liu 《Journal of separation science》2022,45(14):2734-2745
Comprehensive ingredient research is of great significance for understanding the effective material basis of herbal medicines, but due to the diversity and complexity of their phytochemicals, such research is challenging. Here, a multifaceted strategy was proposed to analyze and identify the composition of HuangLian JieDu Decoction based on offline two-dimensional liquid chromatography combined with ultraviolet detection and high-resolution mass spectrometry. Multiple components were separated by two-dimensional liquid chromatography, which consisted of hydrophilic interaction chromatography and reversed-phase liquid chromatography, and then further characterized by high-resolution mass spectrometry with a full mass spectrometry/precursor ion list/data-dependent secondary scan data acquisition method. For data processing, database screening and molecular networking were used to identify the components in HuangLian JieDu Decoction. The offline two-dimensional liquid chromatography combined with ultraviolet detection and a high-resolution mass spectrometry system showed good orthogonality of 76.35% and a high peak capacity of 5175, effectively separating multiple components. Finally, 527 compounds, including 164 alkaloids, 133 terpenoids, 88 flavonoids, 60 phenylpropanoids, 38 organic acids, and 44 other compounds, were characterized. This integrated approach is suitable for the comprehensive characterization of herbal medicines and other complex chemical systems. 相似文献
992.
Fabrication of Mesoporous CoS2 Nanotube Arrays as the Counter Electrodes of Dye‐Sensitized Solar Cells 下载免费PDF全文
Mesoporous cobalt sulfide nanotube arrays on FTO‐coated glass were synthesized by combining three simple technologies: the selective etching of ZnO sacrificial templates, mesoporous Co3O4 formation from cobalt‐chelated chitosan, and ion‐exchange reaction (IER). The mesoporous Co3O4 nanotubes composed of the Co3O4 nanoparticles possess a high surface area and are taken advantage for further removal of templates and IER. The morphologies and crystal structures of the CoS2 nanotube arrays were characterized by SEM, TEM, and XRD analyses. Their electrocatalytic properties were determined by electrochemical analyses including cyclic voltammetry measurements and Tafel polarization. The DSSCs assembled with a CoS2 counter electrode achieved a power conversion efficiency of 6.13 %, which was comparable to that of the DSSC with the Pt counter electrode (6.04 %). This indicates that the mesoporous CoS2 nanotube array can be a low‐cost and efficient alternative for the reduction of electrolytes in DSSCs. 相似文献
993.
994.
测试转台温控箱的计算机控制 总被引:1,自引:0,他引:1
本文针对测试转台温控箱系统的大滞后特性,设计了一种带Smith预估器的PI校正器,并采用了基于8098单片机的计算机控制实现。仿真和实验均表明,文中的控制算法能够有效克服纯大滞后对控制系统稳定性的影响,具有良好的鲁棒性及控制性能,而且实现简单,可靠性好。 相似文献
995.
W. L. Li Y. Zhao W. D. Fei Q. G. Chi W. T. Song 《Journal of Sol-Gel Science and Technology》2010,54(3):335-339
Co-doped ZnO films were successfully fabricated on Si substrates by sol–gel process. The effects of Co concentration and preheating
temperature on the structure and magnetic properties of the Zn1−x
Co
x
O films were systematically studied. The results revealed that the films were highly c-axis oriented and contained no impurity phase. With preheating temperature increasing, the orientation degree of the films
decreased. When the Co concentration and oxygen vacancy of the films are almost changeless, the enhancement of ferromagnetism
in films originates from the orientation degree of the films increasing. 相似文献
996.
Mina Guli Xiaotian Li Kan Zhang Yue Chi 《Journal of Sol-Gel Science and Technology》2010,54(3):329-334
Large, flawless and transparent silica monoliths were prepared at room temperature by solvent evaporation method and loaded
with dye. The composites containing dye molecules were characterized by X-ray diffraction, transmission electron microscopy,
Uv–vis and photoluminescence spectra. A red-shift in photoluminescence spectrum was observed from the composite monolith compared
with that of laser dye in C2H5OH solution. The property of laser narrowing has been shown when the composites are pumped at p = 355 nm by nitrogen laser. 相似文献
997.
Ping Wang Chung‐Hang Leung Dr. Dik‐Lung Ma Dr. Siu‐Cheong Yan Dr. Chi‐Ming Che Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(23):6900-6911
A series of platinum(II) complexes with tridentate ligands was synthesized and their interactions with G‐quadruplex DNA within the c‐myc gene promoter were evaluated. Complex 1 , which has a flat planar 2,6‐bis(benzimidazol‐2‐yl)pyridine (bzimpy) scaffold, was found to stabilize the c‐myc G‐quadruplex structure in a cell‐free system. An in silico G‐quadruplex DNA model has been constructed for structure‐based virtual screening to develop new PtII‐based complexes with superior inhibitory activities. By using complex 1 as the initial structure for hit‐to‐lead optimization, bzimpy and related 2,6‐bis(pyrazol‐3‐yl)pyridine (dPzPy) scaffolds containing amine side‐chains emerge as the top candidates. Six of the top‐scoring complexes were synthesized and their interactions with c‐myc G‐quadruplex DNA have been investigated. The results revealed that all of the complexes have the ability to stabilize the c‐myc G‐quadruplex. Complex 3 a ([PtII L2R ] + ; L2 =2,6‐bis[1‐(3‐piperidinepropyl)‐1H‐enzo[d]imidazol‐2‐yl]pyridine, R =Cl) displayed the strongest inhibition in a cell‐free system (IC50=2.2 μM ) and was 3.3‐fold more potent than that of 1 . Complexes 3 a and 4 a ([PtII L3R ]+; L3 =2,6‐bis[1‐(3‐morpholinopropyl)‐1H‐pyrazol‐3‐yl]pyridine, R =Cl) were found to effectively inhibit c‐myc gene expression in human hepatocarcinoma cells with IC50 values of ≈17 μM , whereas initial hit 1 displayed no significant effect on gene expression at concentrations up to 50 μM . Complexes 3 a and 4 a have a strong preference for G‐quadruplex DNA over duplex DNA, as revealed by competition dialysis experiments and absorption titration; 3 a and 4 a bind G‐quadruplex DNA with binding constants (K) of approximately 106–107 dm3 mol?1, which are at least an order of magnitude higher than the K values for duplex DNA. NMR spectroscopic titration experiments and molecular modeling showed that 4 a binds c‐myc G‐quadruplex DNA through an external end‐stacking mode at the 3′‐terminal face of the G‐quadruplex. Intriguingly, binding of c‐myc G‐quadruplex DNA by 3 b is accompanied by an increase of up to 38‐fold in photoluminescence intensity at λmax=622 nm. 相似文献
998.
Jiefeng Rong Yuwu Chi Yuanjin Zhang Lichan Chen Guonan Chen 《Electrochemistry communications》2010,12(2):270-273
A hydrophobic thiol-functionalized ionic liquid (IL) was synthesized and immobilized tightly on a gold electrode surface via Au–S bond to construct a stable Au–IL|water interface. At the Au–IL|water interface, the electrochemiluminescence (ECL) of luminol-O2 system was investigated. The ECL intensity of luminol-O2 system at the Au–IL|water interface was much larger and more stable than that at Au|water interface. The enhanced ECL mechanism at the Au–IL|water interface was studied and discussed in details. 相似文献
999.
1000.
Porous Si3N4 ceramics with photoluminescence properties were prepared by pressureless sintering using α-Si3N4 powder as raw material and Eu2O3 as sintering additive. Chemical composition, phase formation, microstructure and photoluminescence properties of porous Si3N4 ceramics were studied by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence measurements (PL/PLE). The results show that single Eu2O3 additive promotes α→β transformation but not significant densification. A broad band emission center at 570 nm assigned to Eu2+ is observed, Eu3+ in Eu2O3 is (partially) converted to Eu2+ by reaction with Si3N4, which results in a lower β aspect ratio and β-content compared to the other Ln (Ln=lanthanide) oxide additives. 相似文献