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991.
Hyun Seung Lee 《Tetrahedron letters》2007,48(23):4119-4122
We synthesized poly-substituted pyrrole derivatives 4a-e, 7a-c and 10a-d from the reaction of phenacyl bromide and the aza-Baylis-Hillman adducts 1a-d or their rearranged derivatives 5a-e. The pyrroles were synthesized via the successive N-alkylation, Michael addition, elimination of p-toluenesulfinic acid and oxidative aromatization processes. 相似文献
992.
993.
This paper describes a novel technology-an electric field isolator (EFI)-that can be used for achieving isolated and electrophoretic manipulation of charged biomolecules inside a selected microscopic location. The EFI is a ground ring-shaped electrode (RE) surrounding a centre electrode (CE), which is comprised of a functional unit. When the CE is powered, the ground RE can inhibit the electric field from spreading to the neighbouring functional units. Therefore, the electrophoretic movement of the charged molecules in an electric field, which is based on the principle similar to that of electrophoresis, can be isolated inside a selected location. The ground RE causing this phenomenon is referred to as the EFI. In this paper, we clearly show the functionality of the EFI with mathematical and experimental studies. 相似文献
994.
A reduced third order Markov model is presented to model the kinetics of ethylene‐norbornene copolymerization over rac‐Et(1‐indenyl)2ZrCl2/methylaluminoxane catalyst in solution. In our previous work, we developed a penultimate model (second order Markov model) to describe the copolymerization rate behavior and the copolymer composition. Although the penultimate model provides better predictions of the polymerization kinetics than a simple terminal model, it tends to give underestimated norbornene incorporation rates at high norbornene/ethylene mole ratios in the bulk liquid phase. In this work, we propose a modified third order Markov model to improve the model's capability of calculating norbornene incorporation rate and comonomer sequence distribution. The model parameters have been estimated using a parameter optimization technique. The model simulation results indicate that the rate constant for norbornene insertion into a growing chain depends upon the norbornene microblock length at the propagating center.
995.
Kim JS Lee SJ Jung JH Hwang IC Singh NJ Kim SK Lee SH Kim HJ Keum CS Lee JW Kim KS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(11):3082-3088
The Hinsberg test to recognize the type of amine (1 degrees -3 degrees amines), which has been established for more than 100 years and well documented in textbooks, is not possible without conducting complicated organic reactions. We report for the first time unique chemosensors that are capable of showing selective color changes toward 1 degrees -3 degrees amines as a color version of the Hinsberg test. This simple and straightforward qualitative analysis, using the synthesized novel compounds herein, can be considered a new innovative tool for discriminating 1 degrees -3 degrees amines as an alternative to the historical Hinsberg test. 相似文献
996.
A dense layer of amorphous carbon nanofibers was fabricated by pyrolyzing a thin film of polyimide using a monolayer of gold nanoparticles as a catalyst. 相似文献
997.
A practical procedure for producing silver nanocoated fabric and its antibacterial evaluation for biomedical applications 总被引:4,自引:0,他引:4
Lee HY Park HK Lee YM Kim K Park SB 《Chemical communications (Cambridge, England)》2007,(28):2959-2961
A novel and universal procedure has been developed for producing nanosized stable silver particles on cotton fabrics in a simple and cost-effective manner with complete control of the silver loading level on the fabrics; the antibacterial effect of Ag-nanocoated fabrics on various bacteria was evaluated by growth inhibition; for biomedical applications, skin irritation tests on guinea pigs were performed and no side effects were observed. 相似文献
998.
A practical solid-phase strategy for the synthesis of Delta(5)-2-oxopiperazines via N-acyliminium ion cyclization has been developed. A key step in the library synthesis is tandem acidolytic cleavage with subsequent in situ iminium formation, followed by stable enamide transformation. This approach is exemplified by the preparation of a 192-member pilot library using bromoacetal resins without further purification. 相似文献
999.
Lee JY Kwon J Park CS Lee JE Sim W Kim JS Seo J Yoon I Jung JH Lee SS 《Organic letters》2007,9(3):493-496
[reaction: see text] Calix[4]thiacrowns with hetero-L(1) and a homodonor set (L(2)) were synthesized and characterized by X-ray analysis. From the reaction of L(2) with AgPF(6), disilver complex [Ag(2)(L(2))](PF(6))(2) (1) was isolated. By comparing 1,3-alternate conformations of L(2) and 1, we found a considerable decrease of dihedral angles of two opposite aromatic rings upon complexation. This finding can be explained in terms of the "chopsticks process", which illustrates how Ag(+)-arene pi-coordination occurs. Heterobinuclear complexation of L(1) in solution was also observed. 相似文献
1000.
Cho YS Yi GR Chung YS Park SB Yang SM 《Langmuir : the ACS journal of surfaces and colloids》2007,23(24):12079-12085
In this Article, we report on a packing scheme of monodisperse colloidal nanospheres by aerosol-assisted clustering. When an aqueous suspension of colloidal nanospheres was sprayed into aerosol droplets by an ultrasonic nebulizer, the nanospheres were encapsulated in the aerosol droplets and the evaporation of water from the droplets at high temperatures led to the packings of nanospheres. The configurations of the colloidal nanospheres minimized the interparticle potential energy or the second moment of mass distribution depending on the number of the constituting nanospheres. Other types of nonspherical microparticles or hollow microclusters were also produced by self-organizing organic-inorganic binary colloids of different sizes in an aerosol spray pyrolysis reactor. The aerosol-assisted fabrication of colloidal clusters was very effective as compared to the method based on oil-in-water or water-in-oil emulsions, in which the removal of residual oil was not easy and time-consuming. 相似文献