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991.
We classify all Gorenstein claw-free graphs. Moreover, we provide a new way to construct a Gorenstein graph from another one.
相似文献992.
Wang XJ Chen HY Yu X Wu L Nam KW Bai J Li H Huang X Yang XQ 《Chemical communications (Cambridge, England)》2011,47(25):7170-7172
We report a new synchrotron based in situ X-ray diffraction (XRD) technique to study the chemical delithiation of LiFePO(4). This technique provides a new powerful tool to study chemical reactions with excellent time-resolving power for dynamic studies. 相似文献
993.
Sustainable photochemical NADH regeneration and redox-enzymatic synthesis are accomplished by using CdS nanocrystals grown on the surface of SiO(2) beads. CdS nanocrystals grown on SiO(2) beads worked efficiently as a visible-light absorbing photocatalyst for in situ NADH regeneration with high catalytic activity and minimal loss of activity despite repeated uses. 相似文献
994.
To understand the basic properties of ionic liquids (ILs), we examined the phase behavior and ionic conductivity characteristics using various compositions of different ionic liquids (1-ethyl-3-methylimidazolium hexafluorophosphate [emim] [PF6] and 1-benzyl-3-methylimidazolium hexafluorophosphate [bzmim] [PF6]) in several different alcohols (ethanol, propanol, 1-butanol, 2-butanol, and hexanol). We conducted a systematic study of the impact of different factors on the phase behavior of imidazolium-based ionic liquids in alcohols. Using a new experimental method with a liquid electrolyte system, we observed that the ionic conductivity of the ionic liquid/alcohol was sensitive to the surrounding temperature. We employed Chang et al.’s thermodynamic model [Chang et al. (1997, 1998) [21], [22]] based on the lattice model. The obtained co-ordinated unit parameter from this model was used to describe the phase behavior and ionic conductivities of the given system. Good agreement with experimental data of various alcohol and ILs systems was obtained in the range of interest. 相似文献
995.
Yuhong Oh Donggi Ahn Seunghoon Nam Byungwoo Park 《Journal of Solid State Electrochemistry》2010,14(7):1235-1240
The electrochemical properties of nanoscale Al2O3-coated LiCoO2 thin films were examined as a function of the coating coverage. Al2O3-coated LiCoO2 films showed enhanced cycle-life performance with increasing degree of coating coverage, which was attributed to the suppression
of Co dissolution and F− concentration in the electrolyte. Moreover, an Al2O3-coating layer with partial coverage clearly improved the electrochemical properties, even at 60 °C or with a water-contaminated
electrolyte. Even though metal-oxide coating on LiCoO2 has been actively investigated, the mechanisms of nanoscale coating have yet to be clearly identified. In this article, surface
analysis suggested that the Al2O3-coating layer had transformed to an AlF3
∙3H2O layer during cycling, which inhibited the generation of HF by scavenging H2O molecules present in the electrolyte. 相似文献
996.
Chi‐Ming Ho Dr. Sammi King‐Woon Yau Dr. Chun‐Nam Lok Dr. Man‐Ho So Chi‐Ming Che Prof. 《化学:亚洲杂志》2010,5(2):285-293
The oxidative dissolution of silver nanoparticles (AgNPs) plays an important role in the synthesis of well‐defined nanostructured materials, and may be responsible for their activities in biological systems. In this study, we use stopped‐flow spectrophotometry to investigate the kinetics and mechanism of the oxidative dissolution of AgNPs by H2O2 in quasi‐physiological conditions. Our results show that the reaction is first order with respect to both [Ag0] and [H2O2], and parallel pathways that involve the oxidation of H2O2 and HO2? are proposed. The order of the reaction is independent of the size of the AgNPs (≈5–20 nm). The rate of dissolution increases with increasing pH from 6.0 to 8.5. At 298 K and I=0.1 M , the value of kb is five orders of magnitude higher than that of ka (where ka and kb are the rate constants for the oxidative dissolution of AgNPs by H2O2 and HO2?, respectively). In addition, the effects of surface coating and the presence of halide ions on the dissolution rates are investigated. A possible mechanism for the oxidative dissolution of AgNPs by H2O2 is proposed. We further demonstrate that the toxicities of AgNPs in both bacteria and mammalian cells are enhanced in the presence of H2O2, thereby highlighting the biological relevance of investigating the oxidative dissolution of AgNPs. 相似文献
997.
Isolation of strains degrading poly(Vinyl alcohol) at high temperatures and their biodegradation ability 总被引:2,自引:0,他引:2
Thermophilic strains were isolated for the first time using activated sludge retrieved from waste water treatment plant of a poly(vinyl alcohol) (PVA) producing factory for biodegradation of PVA at relatively high temperatures. The isolated strains were identified to be Geobacillus tepidamans, Brevibacillus brevis and Brevibacillus limnophilus. The former strain degraded PVA for itself, while the latter 2 strains digested PVA symbiotically. PVA degradation activity of the isolated strains was assessed at first by the halo zone size formed around the colonies and finally by the modified Sturm test. The biodegradation rate of PVA was explored also in the presence of different dyes, because most of the waste water from PVA-consuming factories contains waste dyes. 相似文献
998.
We investigated the delamination problem at the metal‐polymer interface and the mechanical buckling of the metal layer at a localized area of the metallic shell under compression between two parallel plates. First, polystyrene (PS) beads were synthesized by dispersion polymerization and then their sulfonation process. After sequential electroless deposition, the average size of multi‐metal coated sulfonated polystyrene (SPS) bead was ca 4.95 µm. Using the electromechanical indentation, the electrical resistance of a single metal‐coated SPS bead decreased with increasing compressive strain without delamination at the metal‐polymer interface, and its electrical resistance showed 5.65 Ω. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
999.
The value-at-risk is an important risk measure that has been used extensively in recent years in portfolio selection and in
risk analysis. This problem, with its known bilevel linear program, is reformulated as a polyhedral DC program with the help
of exact penalty techniques in DC programming and solved by DCA. To check globality of computed solutions, a global method
combining the local algorithm DCA with a well adapted branch-and-bound algorithm is investigated. An illustrative example
and numerical simulations are reported, which show the robustness, the globality and the efficiency of DCA. 相似文献
1000.
Boris S. Mordukhovich Nguyen Mau Nam Bingwu Wang 《Set-Valued and Variational Analysis》2009,17(4):359-387
The primary goal of this paper is to study some notions of normals to nonconvex sets in finite-dimensional and infinite-dimensional spaces and their images under single-valued and set-valued mappings. The main motivation for our study comes from variational analysis and optimization, where the problems under consideration play a crucial role in many important aspects of generalized differential calculus and applications. Our major results provide precise equality formulas (sometimes just efficient upper estimates) allowing us to compute generalized normals in various senses to direct and inverse images of nonconvex sets under single-valued and set-valued mappings between Banach spaces. The main tools of our analysis revolve around variational principles and the fundamental concept of metric regularity properly modified in this paper. 相似文献