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951.
952.
Chia‐Fen Lee Hung‐Hsin Tsai Lee‐Yih Wang Chia‐Fu Chen Wen‐Yen Chiu 《Journal of polymer science. Part A, Polymer chemistry》2005,43(2):342-354
In this study, silica/polystyrene/polyaniline (SiO2/PS/PANI) conductive composite particles were synthesized by four sequential reactions. The nanosized SiO2 particles were synthesized from tetraethoxysilane (TEOS) by a sol–gel process with water as the solvent medium, followed by a surface modification with triethoxyvinylsilane; then the surface modified SiO2 particles were used as seeds to synthesize SiO2/PS composite particles with soapless seeded emulsion polymerization. Finally, the SiO2/PS particles were used as seeds to synthesize the SiO2/PS/PANI conductive composite particles. The sol–gel process of SiO2, the effect of surface modification, and several other factors that influenced polymerization of styrene in the soapless seeded emulsion polymerization will be discussed. Either potassium persulfate (KPS) or 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as the initiator to synthesize the uniform SiO2/PS particles successfully, and the cross‐section morphology of the SiO2/PS particles was found to be of a core–shell structure, with SiO2 as the core, and PS as the shell. The SiO2/PS particles were well dispersed in many organic solvents. In the following step to synthesize SiO2/PS/PANI conductive composite particles, sodium dodecyl sulfate (SDS) played an important role, specifically, to absorb aniline onto the surfaces of the SiO2/PS particles to carry out the polymerization of aniline over the entire surface of the particles. The conductivity of the SiO2/PS/PANI composite particles approached that of semiconductive materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 342–354, 2005 相似文献
953.
Let the R2 space be divided into unit squares where a polyomino is a finite, connected set of unit squares. In this paper, we give a necessary and sufficient condition on tessellating polyominos by observing an unexpected relation between such tessellations and systems of arithmetic progressions. 相似文献
954.
An interesting two-step passivation (with ledge structure and sulphide based chemical treatment) on base surface, for the first time, is demonstrated to study the temperature-dependent DC characteristics and noise performance of an InGaP/GaAs heterojunction bipolar transistor (HBT). Improved transistor behaviors on maximum current gain βmax, offset voltage ΔVCE, and emitter size effect are obtained by using the two-step passivation. Moreover, the device with the two-step passivation exhibits relatively temperature-independent and improved thermal stable performances as the temperature is increased. Therefore, the two-step passivationed device can be used for high-temperature and low-power electronics applications. 相似文献
955.
Hsin‐Jou Fang Ping‐Shan Lai Jia‐Yun Chen Sodio C. N. Hsu Wei‐De Peng Siou‐Wei Ou Yi‐Chun Lai Yen‐Jen Chen Hsuan Chung Yun Chen Ta‐Chou Huang Bo‐Sheng Wu Hsuan‐Ying Chen 《Journal of polymer science. Part A, Polymer chemistry》2012,50(13):2697-2704
This study investigated the synthesis of the biocatalyst, magnesium 2,6‐di‐tert‐butyl‐4‐methylphenoxide (Mg(BHT)2) complex, and the ring‐opening polymerization (ROP) of ε‐caprolactone (CL). The complex demonstrates high catalytic activity and controllable of molecular weight for the ROP of CL in tetrahydrofuran at room temperature, even when polymerization was performed under air. Before this study, the polymerization of CL had never been performed using a magnesium catalyst under air at room temperature. Various forms of alcohols with different purposes were also used as initiators with Mg(BHT)2. The results show that the magnesium complex acts as a perfect catalyst because of its high catalytic activity and control ability without any cytotoxicity in the polymerization of CL, making it suitable for biomedical applications. In addition, nanoparticle formation, cytotoxicity, and phototoxicity of tri‐2‐hydroxyethyl ester [Ce6‐(CH2CH2OPCL)3] were also studied in this article and Ce6‐(CH2CH2OPCL)3 formed nanoparticle can act as a nanophotosensitizer for photodynamic therapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
956.
We describe a generating tree approach to the enumeration and exhaustive generation of k-nonnesting set partitions and permutations. Unlike previous work in the literature which uses the connections of these objects to Young tableaux and restricted lattice walks, our approach deals directly with partition and permutation diagrams. We provide explicit functional equations for the generating functions, with k as a parameter. Key to the solution is a superset of diagrams that permit semi-arcs. Many of the resulting counting sequences also count other well-known objects, such as Baxter permutations, and Young tableaux of bounded height. 相似文献
957.
A Family of Multiply Bonded Dimolybdenum Boraamidinates with the Formal Mo−Mo Bond Orders of 3, 4, 4.5, and 5 下载免费PDF全文
Dr. Duan‐Yen Lu Ting‐Shen Kuo Prof. Dr. Yi‐Chou Tsai 《Angewandte Chemie (International ed. in English)》2016,55(38):11614-11618
A boraamidinato ligand [PhB(N‐2,6‐iPr2C6H3)2]2? was employed to stabilize a new family of multiply bonded dimolybdenum complexes [MoCl(μ‐κ2‐PhB(N‐2,6‐iPr2C6H3)2)]2 ( 4 ) and [Mo(μ‐κ2‐PhB(N‐2,6‐iPr2C6H3)2)]2n? (n=0 ( 5 ), 1 ( 6 ), 2 ( 7 )), with the respective formal Mo?Mo bond orders of 3, 4, 4.5, and 5. Each metal center in 5 – 7 is two‐coordinate with respect to the ligands. Of particular interest is the quadruply bonded dimolybdenum complex 5 , featuring an unprecedented angular conformation. The bent Mo2N4 core of 5 distorts toward planarity upon reduction. As a result, compound 7 features a planar Mo2N4 core, while that of 6 is still bent but less significantly than that of 5 . Additionally, the Mo?Mo bond lengths of 4 – 7 systematically decrease as the valency of the central Mo2 units decreases. Complex 7 features the shortest Mo?Mo bond length (2.0106(5) Å) yet reported. 相似文献
958.
Shasha Sun Xuhui Ning Greg Zhang Yen‐Chung Wang Chuanqi Peng Prof. Dr. Jie Zheng 《Angewandte Chemie (International ed. in English)》2016,55(7):2421-2424
Synergistic effects arising from the conjugation of organic dyes onto non‐luminescent metal nanoparticles (NPs) have greatly broadened their applications in both imaging and sensing. Herein, we report that conjugation of a well‐known pH‐insensitive dye, tetramethyl‐rhodamine (TAMRA), to pH‐insensitive luminescent gold nanoparticles (AuNPs) can lead to an ultrasmall nanoindicator that can fluorescently report local pH in a ratiometric way. Such synergy originated from the dimerization of TAMRA on AuNPs, of which geometry was very sensitive to surface charges of the AuNPs and can be reversely modulated through protonation of surrounding glutathione ligands. Not limited to pH‐insensitive dyes, this pH‐dependent dimerization can also enhance the pH sensitivity of fluorescein, a well‐known pH‐sensitive dye, within a larger pH range, opening up a new pathway to design ultrasmall fluorescent ratiometric nanoindicators with tunable wavelengths and pH response ranges. 相似文献
959.
A Rhizavidin Monomer with Nearly Multimeric Avidin‐Like Binding Stability Against Biotin Conjugates 下载免费PDF全文
Dr. Jeong Min Lee Jung A. Kim Tzu‐Chi Yen Dr. In Hwan Lee Byungjun Ahn Prof. Younghoon Lee Dr. Chia‐Lung Hsieh Prof. Ho Min Kim Prof. Yongwon Jung 《Angewandte Chemie (International ed. in English)》2016,55(10):3393-3397
Developing a monomeric form of an avidin‐like protein with highly stable biotin binding properties has been a major challenge in biotin‐avidin linking technology. Here we report a monomeric avidin‐like protein—enhanced monoavidin—with off‐rates almost comparable to those of multimeric avidin proteins against various biotin conjugates. Enhanced monoavidin (eMA) was developed from naturally dimeric rhizavidin by optimally maintaining protein rigidity during monomerization and additionally shielding the bound biotin by diverse engineering of the surface residues. eMA allowed the monovalent and nonperturbing labeling of head‐group‐biotinylated lipids in bilayer membranes. In addition, we fabricated an unprecedented 24‐meric avidin probe by fusing eMA to a multimeric cage protein. The 24‐meric avidin and eMA were utilized to demonstrate how artificial clustering of cell‐surface proteins greatly enhances the internalization rates of assembled proteins on live cells. 相似文献
960.
Hu J Zhuang X Huang L Le L Chen X Wei Y Jing X 《Langmuir : the ACS journal of surfaces and colloids》2008,24(23):13376-13382
A simple triblock copolymer, mPEG750-aniline pentamer-mPEG750, was prepared by condensation polymerization. The solubility of aniline pentamer in this kind of copolymer was improved in common solvents especially in aqueous solution, and the electroactivity of this copolymer was confirmed by UV-vis and CV in aqueous solution. When aniline pentamer was in its emeraldine state, the copolymer spontaneously self-assembled into large spheres (with diameters up to 1000 nm) in acidic aqueous solution (pH < 3), and into microspheres (with diameters of about 300 nm) in alkali aqueous solution, while the size of the aggregates decreased with the increase of pH. For reversible transition between the large spheres and microspheres under the change of the pH and potential, which changed the doping state and the oxidation state, respectively, the copolymer has potential applications in sensors, controlled drug release, and so forth. 相似文献