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991.
Zeng Q Li T Cash B Li S Xie F Wang Q 《Chemical communications (Cambridge, England)》2007,(14):1453-1455
Horse spleen apoferritin, the hollow protein shell derived from ferritin, a special biological nanoparticle, can be chemoselectively modified at the lysine residues, which affords a robust scaffold for further chemical reactions including Cu(i)-catalyzed azide-alkyne cycloaddition reaction and atom transfer radical polymerization reaction. 相似文献
992.
993.
Large-eddy-simulation of 3-dimensional Rayleigh-Taylor instability in incompressible fluids 总被引:1,自引:0,他引:1
The 3-dimensional incompressible Rayleigh-Taylor instability is numerically studied through the large-eddy-simulation ( LES)
approach based on the passive scalar transport model. Both the instantaneous velocity and the passive scalar fields excited
by sinusoidal perturbation and random perturbation are simulated. A full treatment of the whole evolution process of the instability
is addressed. To verify the reliability of the LES code, the averaged turbulent energy as well as the flux of passive scalar
are calculated at both the resolved scale and the subgrid scale. Our results show good agreement with the experimental and
other numerical work. The LES method has proved to be an effective approach to the Rayleigh-Taylor instability. 相似文献
994.
本文通过无水三氯化希土与等摩尔的甲基环戊二烯基钠(Cp′Na)在四氢呋喃(THF)中反应,合成了八个新的中性甲基环戊二烯基希土二氯化合物Cp′LnCl2·3THF[Ln=Sm(1), Eu(2), Gd(3), Tb(4), Dy(5), Ho(6), Er(7), Y(8)],并研究了茂环上甲基取代基对一茂二氯希土配合物分子结构及稳定性的影响。元素分析、红外光谱和质谱鉴定结果表明这八个化合物都是溶剂化的单体结构,其中配合物7的结构还用单晶X射线分析确证。 相似文献
995.
The critical micelle concentration (CMC) has been determined for the gemini surfactant trimethylene-1,3-bis(dodecyldimethyl ammonium bromide)12-s-12,2Br?1 by means of electricity conductivity measurements. For the same number of carbon atoms in the hydrophobic chain per hydrophilic head group, geminis have CMC values well below those of conventional single-chain cationic surfactants. The CMC of 12-3-12 reduces with the addition of n-alcohol except ethanol and with the increase of n-alcohol chain length as well as increase of concentration of n-butanol and sodium chloride. Steady-state fluorescence quenching technology has been employed to study the aggregation number of micelle, which increases with increase in the length of n-alcohol. The Kraft temperature measurements also indicate that the stability of solid surfactant hydrate decreases along with the improvement of concentration of n-butanol and sodium chloride. 相似文献
996.
Measurements of NO2 mixing ratios with topographic target light scattering-differential optical absorption spectroscopy system and comparisons to point monitoring technique 下载免费PDF全文
A topographic target light scattering-differential optical absorption spectroscopy(ToTaL-DOAS) system is developed for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases.The telescope of the ToTaL-DOAS system points to targets which are located at known distances from the measurement device and illuminated by sunlight.Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets.A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011.The measurement data are compared with concentrations measured by the point monitoring technique at the same site.The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path. 相似文献
997.
998.
A new collectively fixed point theorem for a family of set-valued mappings defined on product spaces of non-compact topological spaces without linear structure is proved and some special cases are also discussed. As applications, some non-empty intersection theorems of sets with convex sections and equilibrium existence theorem of abstract economies are obtained under much weaker assumptions. Our results includes a number of known results as many special cases. 相似文献
999.
Yunrui Huang Qingxiang Zhou Junping Xiao Guohong Xie 《Journal of separation science》2010,33(14):2184-2190
This article described a new method for the sensitive determination of organophosphorus pesticides in water samples using SPE in combination with GC‐flame photometric detection. In the procedure of method development, TiO2 nanotubes were used as SPE adsorbents for the enrichment of organophosphorus pesticides from water samples. Several factors, such as eluent and its volume, sample pH, sample volume, sample flow rate, and concentration of humic acid, were optimized. Under the optimal conditions, the proposed method had good linear ranges as 0.1–40 μg/L for each of them, LOD of 0.11, 0.014, and 0.0025 μg/L, and LOQs of 0.37, 0.047, and 0.0083 μg/L for chlorpyrifos, phorate, and methyl parathion, respectively. The proposed method was validated with real environmental water samples and the spiked recoveries were over the range of 86.5–115.1%. All these results indicated that TiO2 nanotubes, as a new SPE adsorbent, would be used widespread for the preconcentraiton and determination of environmental pollutants in the future. 相似文献
1000.
Development of a magnetic solid‐phase extraction coupled with high‐performance liquid chromatography method for the analysis of polyaromatic hydrocarbons 下载免费PDF全文
Yan Ma Jiawen Xie Jing Jin Wei Wang Zhijian Yao Qing Zhou Aimin Li Ying Liang 《Journal of separation science》2015,38(14):2517-2525
A novel magnetic solid phase extraction coupled with high‐performance liquid chromatography method was established to analyze polyaromatic hydrocarbons in environmental water samples. The extraction conditions, including the amount of extraction agent, extraction time, pH and the surface structure of the magnetic extraction agent, were optimized. The results showed that the amount of extraction agent and extraction time significantly influenced the extraction performance. The increase in the specific surface area, the enlargement of pore size, and the reduction of particle size could enhance the extraction performance of the magnetic microsphere. The optimized magnetic extraction agent possessed a high surface area of 1311 m2/g, a large pore size of 6–9 nm, and a small particle size of 6–9 μm. The limit of detection for phenanthrene and benzo[g,h,i]perylene in the developed analysis method was 3.2 and 10.5 ng/L, respectively. When applied to river water samples, the spiked recovery of phenanthrene and benzo[g,h,i]perylene ranged from 89.5–98.6% and 82.9–89.1%, respectively. Phenanthrene was detected over a concentration range of 89–117 ng/L in three water samples withdrawn from the midstream of the Huai River, and benzo[g,h,i]perylene was below the detection limit. 相似文献