排序方式: 共有38条查询结果,搜索用时 296 毫秒
1.
Dong Il Han Hoe Jin Hah Hong-Woo Park Sang Man Koo 《Journal of Sol-Gel Science and Technology》2004,32(1-3):47-51
Composite silica particles were synthesized by a two-step (acid-base) process in an aqueous solution with a mixture of organoalkoxysilane monomers. The two-step process separates the hydrolysis and condensation procedures to easily control condensation rate. In this study, the silane monomers used were phenyltrimethoxysilane (PTMS), vinyltrimethoxysilane (VTMS), methyltrimethoxysilane (MTMS), and tetraethyl-orthosilicate (TEOS). The physical properties of the resultant composite particles were investigated with the change in the molar ratio of monomers. The size of the particles increased with increasing the molar ratio of RaSi(OR)3/RbSi(OR)3 or RaSi(OR)3/TEOS (Ra: phenyl; Rb: vinyl, methyl). 相似文献
2.
Preparation of Silver Nanoparticles through Alcohol Reduction with Organoalkoxysilanes 总被引:1,自引:0,他引:1
Hoe Jin Hah Sang Man Koo Sang Hoon Lee 《Journal of Sol-Gel Science and Technology》2003,26(1-3):467-471
Silver nanoparticles of narrow size distribution were prepared through the chemical reduction in an alcohol solution with several organoalkoxysilanes. In this system, organoalkoxysilanes served as a stabilizer, protecting silver nanoparticles from aggregation. The changes in size and morphology of colloidal silver nanoparticles were investigated with the addition of organoalkoxysilanes such as 3-aminopropyltriethoxysilane (APS), methyltriethoxysilane (MTS), phenyltrimethoxysilane (PTS), vinyltriethoxysilane (VTS), and 3-glycidoxypropyltrimethoxysilane (GPS) as stabilizers. The organic functional groups of organoalkoxysilanes interact with silver ions and clusters, which stabilize silver nanoparticles in the system. The silver nanoparticles obtained were characterized with transmission electron microscopy (TEM), UV-vis spectroscopy, etc. 相似文献
3.
一维光子晶体缺陷模激光器的放大特性 总被引:10,自引:0,他引:10
光子晶体中引入缺陷后将形成缺陷模,这些缺陷模在增益介质中将被放大形成激光。基于麦克斯韦方程和速率方程相结合的模型,用时域有限差分法(FDTD)计算和分析了一维单缺陷光子晶体激光器中缺陷模的空间分布和频谱特性,以及这些缺陷模的放大特性,主要研究了缺陷层的厚度、晶体层数对缺陷模放大特性的影响。模拟结果显示,类似于传统激光腔的腔模,这些缺陷模能够被放大,形成激光。调整缺陷层的厚度、晶体层数等结构参量,将改变缺陷模的谐振,激射频率以及空间分布,这将直接影响激射阈值和饱和特性。增加晶体的层数,激光器的阈值将降低,饱和值将增加,但晶体层数增加到一定限度时,这种增减趋势变弱。模拟结果证明了有效层数的存在。 相似文献
4.
Chan?Yoon?Jung Hoe?Jin?Hah Seung?Hoon?Han Hong-Woo?Park Sang?Man?KooEmail author 《Journal of Sol-Gel Science and Technology》2005,33(1):81-85
Tin oxide-doped hybrid particles were prepared by a wet chemical process with organic-inorganic (phenyl/silica) hybrid particles in an alcoholic solution. The phenyl/silica hybrid particles, with a diameter of ca. 790 nm were used as a new support material for tin oxide (SnO2) particles from tin(IV) chloride. The surface of the particles was modified via nitration of aromatic groups in the particles, to promote formation of the tin oxide coating on the particles. The thickness and surface morphology of the tin oxide layer coated on the nitrated-phenyl/silica hybrid particles could be controlled by varying the tin(IV) chloride concentration and reaction time. The size and morphology of the resultant particles were investigated with field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The particles obtained were also characterised by infrared (FTIR) and solid-state 13C magic angle spinning nuclear magnetic resonance (13C-CP/MAS NMR) spectroscopy. The effect of processing parameters on the crystallinity and structure of the doped hybrids were confirmed by X-ray diffraction (XRD) patterns. 相似文献
5.
Jae Yoon Chung Hwan Won Chung Seung Joo Cho Jung-Mi Hah Art E. Cho 《Journal of computer-aided molecular design》2010,24(5):385-397
Three dimensional (3D) quantitative structure-activity relationship studies of 37 B-Raf inhibitors, pyrazole-based derivatives,
were performed. Based on the co-crystallized compound (PDB ID: 3D4Q), several alignment methods were utilized to derive reliable
comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) models. Receptor-guided
alignment with quantum mechanics/molecular mechanics (QM/MM) minimization led to the best CoMFA model (q
2 = 0.624, r
2 = 0.959). With the same alignment, a statistically reliable CoMSIA model with steric, H-bond acceptor, and hydrophobic fields
was also derived (q
2 = 0.590, r
2 = 0.922). Both models were validated with an external test set, which gave satisfactory predictive r
2 values of 0.926 and 0.878, respectively. Contour maps from CoMFA and CoMSIA models revealed important structural features
responsible for increasing biological activity within the active site and explained the correlation between biological activity
and receptor-ligand interactions. New fragments were identified as building blocks which can replace R1-3 groups through combinatorial
screening methods. By combining these fragments a compound with a high bioactivity level prediction was found. These results
can offer useful information for the design of new B-Raf inhibitors. 相似文献
6.
Yong Hah Lee 《manuscripta mathematica》1999,99(3):311-328
We prove that the dimension of harmonic functions with finite Dirichlet integral is invariant under rough isometries between
Riemannian manifolds satisfying the local conditions, expounded below. This result directly generalizes those of Kanai, of
Grigor'yan, and of Holopainen. We also prove that the dimension of harmonic functions with finite Dirichlet integral is preserved
under rough isometries between a Riemannian manifold satisfying the same local conditions and a graph of bounded degree; and
between graphs of bounded degree. These results generalize those of Holopainen and Soardi, and of Soardi, respectively.
Received: 23 July 1998 / Revised version: 10 February 1999 相似文献
7.
De Novo Design and Synthesis of a γ‐Turn Peptidomimetic Scaffold and Its Application as JNK3 Allosteric Ligand
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As a way to develop a neuroprotective agent for the JNK3‐JIP1‐binding site, peptidomimetics of JIP‐1 as JNK3 allosteric regulators have been examined. The study consisted of in silico scaffold hopping, molecular docking, solution and solid‐phase peptide syntheses, and Kd measurements using surface plasmon resonance. As a peptidomimetic of JIP1, heptamer mimetic 16 (Kd=2.72 μm ) displayed a higher affinity than decamer JIP1 (Kd=23.6 μm ). The high affinity of 16 implies that the characteristic γ‐turn mimetic structure, “”Φ‐X‐Φ“ hydrophobic motif in 16 , increased its affinity toward the JIP‐site of JNK3. 相似文献
8.
Yong Hah Lee 《Proceedings of the American Mathematical Society》2005,133(11):3411-3420
We pose and solve the asymptotic Dirichlet problem for the Schrödinger operator via rough isometries on a certain class of Riemannian manifolds. With suitable potentials, we give the solvability of the problem for a naturally defined class of data functions.
9.
Light-activatable ("caged") proteins have been used to correlate, with exquisite temporal and spatial control, intracellular biochemical action with global cellular behavior. However, the chemical or genetic construction of caged proteins is nontrivial, with subsequent laborious introduction into living cells, potentially problematic competition with natural endogenous counterparts, and challenging intracellular incorporation at levels equivalent to the natural enzymes. We describe the design, synthesis, and characterization of small molecular equivalents of a caged Src kinase. These compounds are easy to prepare and function by inhibiting the action of the natural unmodified enzyme. 相似文献
10.
C(60)-functionalized gold nanoparticle films were self-assembled on the reactive surface of glass slides functionalized with 3-aminopropyltrimethoxysilane. The functionalized glass slides were alternately soaked in the solutions containing unmodified C(60) and 4-aminothiophenoxide/hexane thiolate-protected gold nanoparticles. Organic reaction (amination) facilitated the layer-by-layer multilayer film assembly. C(60)-functionalized gold nanoparticle films have grown up to several layers (upto 5 layers were examined) depending on the immersion time. The assembled nanoparticle films were characterized using UV-vis spectroscopy. The chemical stability of C(60)-gold nanoparticle films was studied by monitoring the changes in absorbance after the immersion of the films in acidic solutions. The ultrasonic stability of these nanoparticle films was studied by exposing them to ultrasonic irradiated surrounding, which results in the aggregation of nanoparticles on solid surfaces. 相似文献