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991.
A heavy fourth generation with a mass of the order of 400 GeV or more could trigger dynamical electroweak symmetry breaking by forming condensates through the exchange of a fundamental Higgs scalar doublet. The dynamics leading to these condensates is studied within the framework of the Schwinger–Dyson equation. This scenario leads to the presence of three (two composite and one fundamental) Higgs doublets, with interesting phenomenological implications. In addition, this dynamical phenomenon occurs in the vicinity of the energy scale where the restoration of scale symmetry might happen. 相似文献
992.
Hung AM Konopliv NA Cha JN 《Langmuir : the ACS journal of surfaces and colloids》2011,27(20):12322-12328
We demonstrate a purely solvent-based approach to assembling CdSe nanorods into vertically aligned, hexagonally packed monolayers in solution. Nanorods were dispersed in a mixture of good solvent with high vapor pressure and bad solvent with low vapor pressure, and preferential evaporation of the good solvent led to ordered assembly under conditions of continuously decreasing solvent quality. No applied external bias, extensive control of drying conditions, exceptionally monodisperse nanoparticles, or high concentrations of additives were required. This clean and facile method yielded ordered nanorod sheets of up to 7.5 μm wide with potential use as active materials in unique applications. 相似文献
993.
Lou JL Shiu HW Chang LY Wu CP Soo YL Chen CH 《Langmuir : the ACS journal of surfaces and colloids》2011,27(7):3436-3441
We have grown 1-dodecandthiol (DDT) monolayer on a bare Si(111) surface through ultraviolet-assisted photochemical reaction. The resulting monolayer was investigated by means of water contact angle measurement, synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy, and polarization-dependent near-edge X-ray absorption fine structure spectroscopy. These combined probes for characterization reveal a hydrophobic ambient surface; the DDT was directly attached to Si through a Si-S bond, and the molecules formed an ordered monolayer with an average tilt angle of 57° of the alkyl chains relative to the substrate surface. 相似文献
994.
Hung WY Liu B Shou W Wen TB Shi C Sung HH Williams ID Lin Z Jia G 《Journal of the American Chemical Society》2011,133(45):18350-18360
The electrophilic substitution reactions of metallabenzynes Os(≡CC(R)═C(CH(3))C(R)═CH)Cl(2)(PPh(3))(2) (R = SiMe(3), H) were studied. These metallabenzynes react with electrophilic reagents, including Br(2), NO(2)BF(4), NOBF(4), HCl/H(2)O(2), and AlCl(3)/H(2)O(2) to afford the corresponding bromination, nitration, nitrosation, and chlorination products. The reactions usually occur at the C2 and C4 positions of the metallacycle. These observations support the notion that metallabenzynes exhibit aromatic properties. 相似文献
995.
A liquid phase microextraction method using hollow fiber to support extraction solvent was developed for enrichment of trace level chloroanilines in environmental water samples. Target analytes, 2-chloroaniline, 3-chloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, and 3,5-dichloroaniline were determined using gas chromatography-flame ionization detector after extraction. Experimental conditions that affect extraction efficiency were investigated and optimized. The proposed method showed a wide linear range from lower ??g L?1 to 1,000 ??g L?1, low detection limits (??5.1 ??g L?1), and reasonable relative standard deviations (RSDs < 13%). Feasibility of the method was evaluated by analyzing river water samples collected from the Hudson River and the East River in New York City. 相似文献
996.
997.
Hung P. Tong-Viet 《Monatshefte für Mathematik》2013,172(2):189-206
Let $G$ be a finite group and let ${\mathrm{Irr}}(G)$ denote the set of all complex irreducible characters of $G.$ Let ${\mathrm{cd}}(G)$ be the set of all character degrees of $G.$ For each positive integer $d,$ the multiplicity of $d$ in $G$ is defined to be the number of irreducible characters of $G$ having the same degree $d.$ The multiplicity pattern ${\mathrm{mp}}(G)$ is the vector whose first coordinate is $|G:G^{\prime }|$ and for $i\ge 1,$ the $(i+1)$ th-coordinate of ${\mathrm{mp}}(G)$ is the multiplicity of the $i$ th-smallest nontrivial character degree of $G.$ In this paper, we show that every nonabelian simple group with at most $7$ distinct character degrees is uniquely determined by the multiplicity pattern. 相似文献
998.
999.
Emmanuel A. Gonzalez John Y. Hung Lubomir Dorcak Jan Terpak Ivo Petras 《Central European Journal of Physics》2013,11(6):868-880
The number of studies on the control of fractional-order processes—processes having dynamics described by differential equations of arbitrary order—has been increasing in the past two decades and it is now ubiquitous. Various methods have emerged and have been proven to effectively control such processes—usually resulting in fractional-order controllers similar to their conventional integer-order counterparts, which include, but are not limited to fractional PID and fractional lead-lag controllers. However, such methods require a lot of computational effort and fractional-order controllers could be challenging when it comes to their synthesis and implementation. In this paper, we propose a simple yet effective delay-based controller with the use of the Posicast control methodology in controlling the overshoot of a fractional-order process of the class $\mathcal{P}:\left\{ {P\left( s \right) = {1 \mathord{\left/ {\vphantom {1 {\left( {as^\alpha + b} \right)}}} \right. \kern-0em} {\left( {as^\alpha + b} \right)}}} \right\}$ having orders 1 < α < 2. Such controllers have proven to be easy to implement because they only require delays and summers. In this paper, the Posicast control methodology introduced in the past few years is modified to minimize the overshoot of the processes step response to a level that is acceptable in control engineering and automation practices. Furthermore, proof of the existence of overshoot for such class of processes, as well as the determination of the peak-time of the open-loop response of a fractional-order process of the class P is presented. Validation through numerical simulations for a class of fractional-order processes are presented in this paper. 相似文献
1000.
F. Rösch Tran Kim Hung S. Dittrich R. Ludwig G. V. Buklanov R. Dreyer 《Isotopes in environmental and health studies》2013,49(8):355-363
Ion mobilities of carrier-free 239Np(V) have been measured in aqueous solutions, T = 298.1 (1) K. Ion mobilities of 239NpO2 + and its dependencies on pH of acidic inert electrolytes have been measured. In alkaline solutions the stoichimetric hydrolysis constants of NpO2(OH) as well as NpO2(OH)2 ? have been obtained. Complex formations of 239Np(V) with oxalate, tartrate, sulphate, acetate and citrate ligands have been studied in neutral solutions. 相似文献