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91.
Designing optical-fiber modulators by using magnetic fluids 总被引:1,自引:0,他引:1
To reduce interface loss between optical fibers and devices in telecommunication systems, the development of an optical-fiber-based device that can be fused directly with fibers is important. A novel optical modulator consisting of a bare fiber core surrounded by magnetic fluids instead of by a SiO2 cladding layer is proposed. Applying a magnetic field raises the refractive index of the magnetic fluid. Thus we can control the occurrence of total reflection at the interface between the fiber core and the magnetic fluid when light propagates along the fiber. As a result, the intensity of the outgoing light is modulated by variation in field strength. Details of the design, fabrication, and working properties of such a modulator are presented. 相似文献
92.
Horng Chin Yeh B. E. Eichinger N. H. Andersen 《Journal of polymer science. Part A, Polymer chemistry》1982,20(9):2575-2602
Polymers containing pendant acetylacetonate (acac) groups suitable for crosslinking through metal complex formation are described. Diene-based copolymers, polystyrene, and polydimethylsiloxane, each containing a measurable number of acac groups distributed along the chains, were synthesized. The polymers were studied both for the amount of acac ligand and for their crosslinking reactions with selected transition metals by ultraviolet (UV) second-derivative spectroscopy. The UV analyses of the polymer systems were compared with their monomer analogs, and the results confirm that the crosslinking chelation reactions of polymer compounds are similar to those of model compounds. Homogeneous chelate crosslinking conditions were developed by using transition-metal salts such as Cu(laurate)2, Fe(laurate)3, and Cr(laurate)3 in solvents such as chloroform and benzene. Polymeric ligands containing 1–5% acac in solution at various concentrations were reacted to form both inter- and intramolecular crosslinkages. The kinetic stability of the chelate crosslinks has been studied by a unique ligand exchange–gel solubility relationship. 相似文献
93.
Sheng-Hung Wu Chu-Chin Hsieh Chung-Cheng Chiang Jao-Jia Horng Wei-Ping Pan Chi-Min Shu 《Journal of Thermal Analysis and Calorimetry》2012,109(2):945-950
Volatile organic compounds (VOCs) and greenhouse gases are the main factors involved in pollution control and global warming. Various treatment methods involving incineration, adsorption, etc., have been employed to reduce VOCs and greenhouse gases concentration in the operating environment and atmosphere. Activated carbon, zeolite, silica gel, and alumina have been broadly used to adsorb pollutants in various industrial applications. Based on the promising effect of adsorption, we analyzed and identified the thermal phenomena of home-made zeolite using various instruments. The endothermic reaction under 100?°C of home-made zeolite was identified as steam adsorption, which is an important discovery. The optimal adsorption temperatures of home-made zeolite have been determined at 200?C550?°C. 相似文献
94.
Collagen is an important and widely used biomaterial and therapeutic. The construction of large-scale collagen structures via the self-assembly of small collagen-related peptides has been extensively studied in the past decade. Here, we report a highly effective and simple means to assemble small synthetic collagen-related peptides into various higher-order structures by utilizing metal-histidine coordination. In this work, two short collagen-related peptides in which histidine residues were incorporated as metal binding sites were designed and chemically synthesized: HG(PPG)(9)GH (X9) and HG(PPG)(4)(PHG)(PPG)(4)GH (PHG). Circular dichroism measurements indicated that these two peptides form only marginally stable collagen triple helices but that their stability can be increased upon the addition of metal ions. Dynamic light scattering analyses, turbidity measurements, TEM, and SEM results demonstrated the metal ion-dependent self-assembly of X9 and PHG into supramolecular structures ranging from various nanofibrils to microscale spherical, laminated, and granulated assemblies. The topology and size of these higher-order structures depends both on the metal ion identity and the location of the binding sites. Most intriguingly, the assembled fibrils show similar D-periodicity to that of natural collagen. Our results demonstrate that metal-histidine coordination can serve as an effective force to induce the self-assembly of unstable collagen-related peptides into higher-order structures. 相似文献
95.
Min‐Shiun Chao Horng‐Hwa Lu Ming‐Liao Tsai Tsung‐Hsuan Hsieh Chien‐Min Lin 《中国化学会会志》2009,56(5):916-922
The self‐assembly of Co(II) with two diaminodiamide ligands, 4,7‐diazadecanediamide and 4,8‐diazaundecanediamide, gave two different crystals, [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]Cl2 ( 1 ) [Co(C9H20N4O2)(Cl)(H2O)]·Cl·2H2O ( 2 ). Structures of 1 and 2 were characterized by single‐crystal X‐ray diffraction analysis. Structural data for 1 shows a novel type of binuclear complex with distorted octahederal coordination geometry around the Co atoms through the hydroxo bridges. By using inter‐connector N‐H···N hydrogen bonding interactions as building forces, each cationic moiety [(C8H18N4O2)Co(OH)2Co(C8H18N4O2)]2+ is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chain‐like structure. The chains are further connected into a 2D layer in a (4,4)‐topology via N‐H···Clfree hydrogen‐bonding interactions. Structural data for 2 indicate that the cobalt atom adopts a six‐coordinated N2O4 environment, giving a distorted octahedral geometry, where two N‐ and two O‐donor sets of ligand located at equatorial positions and one water and one chloride occupied at axial positions. Through NH···Cl‐Co and OH···Cl‐Co contacts, each cationic moiety [Co(C9H20N4O2)(Cl)(H2O)]+ in 2 is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to steric strain effect of the diaminodiamide ligand. 相似文献
96.
Wen‐Chi Chang Tzong‐Yi Lee Dray‐Ming Shien Justin Bo‐Kai Hsu Jorng‐Tzong Horng Po‐Chiang Hsu Ting‐Yuan Wang Hsien‐Da Huang Rong‐Long Pan 《Journal of computational chemistry》2009,30(15):2526-2537
Tyrosine sulfation is a post‐translational modification of many secreted and membrane‐bound proteins. It governs protein‐protein interactions that are involved in leukocyte adhesion, hemostasis, and chemokine signaling. However, the intrinsic feature of sulfated protein remains elusive and remains to be delineated. This investigation presents SulfoSite, which is a computational method based on a support vector machine (SVM) for predicting protein sulfotyrosine sites. The approach was developed to consider structural information such as concerning the secondary structure and solvent accessibility of amino acids that surround the sulfotyrosine sites. One hundred sixty‐two experimentally verified tyrosine sulfation sites were identified using UniProtKB/SwissProt release 53.0. The results of a five‐fold cross‐validation evaluation suggest that the accessibility of the solvent around the sulfotyrosine sites contributes substantially to predictive accuracy. The SVM classifier can achieve an accuracy of 94.2% in five‐fold cross validation when sequence positional weighted matrix (PWM) is coupled with values of the accessible surface area (ASA). The proposed method significantly outperforms previous methods for accurately predicting the location of tyrosine sulfation sites. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 相似文献
97.
Horng‐Jyh Harn Yi‐Lin Chen Po‐Cheng Lin Yeung‐Leung Cheng Shin‐Chun Lee Tzyy‐Wen Chiou Hsueh‐Hui Yang 《中国化学会会志》2010,57(2):180-188
To explore the potential tumor markers for lung adenocarcinoma, two‐dimensional gel electrophoresis (2DE) coupled with nano‐LC/MS/MS was used to analyze the differentially expressed proteins in 10 surgical resected lung adenocarcinoma tissues. 16 proteins were significantly different between the cancer tissue and adjacent normal tissue. Galectin‐1, peroxiredoxin II (Prx II), proapolipoprotein, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), aldolase A, enolase 1, neuropolypeptide h3, Prx V, cyclophilin A, vimentin, protein disulfide isomerase (PDI), tropomyosin 3 (TPM 3), glutathione S‐transferase Pi (GST‐Pi), manganese superoxide dismutase (MnSOD), and cofilin 1 were up‐regulated in the cancer tissue. On the other hand, profilin was down‐regulated in the cancer tissue. Among these proteins, six proteins were validated by Western blot analysis. The identified proteins contributing to the spectrum of cancer progression may be used as potential diagnostic biomarkers for lung adenocarcinomas. 相似文献
98.
Yasushi Nishihara Yukiko Doi Seisuke Izawa Horng‐Yi Li Yoshiaki Inoue Masaaki Kojima Jwu‐Ting Chen Kentaro Takagi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):485-491
Doubly fuctionalized polar norbornenes bearing the cyano and ester groups in 2,3‐positions are synthesized and enantiomers are separated by high performance liquid chromatography (HPLC) with a chiral stationary phase. These optically active monomers are polymerized by ruthenium carbene catalysts, and high yields of the polymers were obtained. The chiral monomer bearing ethyl ester gave an optically active polymer of lower, but opposite sign of optical rotation (monomer [α]D = +61.0°, polymer [α]D = ?3.1°). The circular dichroism (CD) of the obtained chiral polymers gave a Cotton effect. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 485–491, 2010 相似文献
99.
Recent investigations on the stability of proteins have demonstrated various structural factors, but few have considered sequence factors such as protein motifs. These motifs represent highly conserved regions and describe critical regions that may only exist on proteins that remain functional at high temperatures. This investigation presents a method for identifying and comparing corresponding mesophilic and thermophilic sequence motifs between protein families. Discriminative motifs that are conserved only in the mesophilic or thermophilic subfamily are identified. Analysis of the results shows that, although the subfamilies of most protein families share similar motifs, some discriminative motifs are present in particular thermophilic/mesophilic subfamilies. The thermophilic discriminative motifs are conserved only in thermophilic organisms, revealing that physiochemical principles support thermostability. 相似文献
100.