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941.
In the present work we investigated a novel triplet ground-state germylenoid HB=GeLiF as well as its insertion reactions with RH(R = F,OH and NH2) using the DFT B3LYP and QCISD methods for the first time.Geometry optimization calculations show that the triplet HB=GeLiF has three equilibrium structures,in which the four-membered ring structure is the most stable with the lowest energy.All mechanisms of the three insertion reactions of germylenoid HB=GeLiF with RH(R = F,OH,and NH2) are identical to each other.Based on the calculated results,it is concluded that under the same conditions the insertion reactions should occur easily in the order of H-F > H-OH > H-NH2.In THF solvent the insertion reactions get more difficult than in the gas phase.  相似文献   
942.
For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D‐printing‐manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram‐positive or gram‐negative bacterial species. Zinc atoms as outermost layer (ZnO?Zn) showed a more pronounced antibacterial effect towards gram‐negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO?O) showed a stronger antibacterial activity against gram‐positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn2+ concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species.  相似文献   
943.
944.
A series of imidacloprid derivatives containing an azopyridine motif as a photoswitchable functional group were designed and synthesized. The new version of photoresponsive imidacloprid analogues showed improved solubility in comparison with their azobenzene analogues. 1.2 to 2-fold activity difference was observed for these azopyridine-imidacloprids against house fly (Musca domestica) and cowpea aphid (Aphis craccivora) upon irradiation.  相似文献   
945.
946.
Tin oxide nanoparticles (SnO2 NPs) have been encapsulated in situ in a three‐dimensional ordered space structure. Within this composite, ordered mesoporous carbon (OMC) acts as a carbon framework showing a desirable ordered mesoporous structure with an average pore size (≈6 nm) and a high surface area (470.3 m2 g?1), and the SnO2 NPs (≈10 nm) are highly loaded (up to 80 wt %) and homogeneously distributed within the OMC matrix. As an anode material for lithium‐ion batteries, a SnO2@OMC composite material can deliver an initial charge capacity of 943 mAh g?1 and retain 68.9 % of the initial capacity after 50 cycles at a current density of 50 mA g?1, even exhibit a capacity of 503 mA h g?1 after 100 cycles at 160 mA g?1. In situ encapsulation of the SnO2 NPs within an OMC framework contributes to a higher capacity and a better cycling stability and rate capability in comparison with bare OMC and OMC ex situ loaded with SnO2 particles (SnO2/OMC). The significantly improved electrochemical performance of the SnO2@OMC composite can be attributed to the multifunctional OMC matrix, which can facilitate electrolyte infiltration, accelerate charge transfer, and lithium‐ion diffusion, and act as a favorable buffer to release reaction strains for lithiation/delithiation of the SnO2 NPs.  相似文献   
947.
Activated carbon is very effective for simultaneous removal of multiple pollutants. The adsorption of SO2 and chlorobenzene modeling of VOCs on activated carbon was investigated in a fixed-bed reactor by four kinds of activated carbon. The results show that the SO2 adsorption is affected by the BET surface and basic functional groups as C=O and π–π* groups of the carbon, while the chlorobenzene adsorption is strongly affected by the carbon pore structure, with the micropore volume deciding the adsorption amount and larger pores increasing the adsorption rate. The chlorobenzene adsorption is little affected by the chemical properties of activated carbon as the O/C ratio detected by XPS. The effect of SO2 on the chlorobenzene adsorption was investigated, with the results showing the SO2 seriously restricts the individual chlorobenzene adsorption and this effect becomes smaller in the presence of O2. The adsorption products were analyzed by TPD-MS and the initial decomposition temperatures are 380 K for chlorobenzene and 500 K for SO2, showing that SO2 is much more stable adsorbed than chlorobenzene. The changes of the carbon functional groups that the CO2 desorption peak emerges at 700 K and decreases at 1000 K with the chlorobenzene adsorption, were observed by TPD-MS, indicating that the lactone and quinone groups on the carbon are likely to combine with the chlorobenzene and form weakly chemisorbed chlorobenzene.  相似文献   
948.
Xue  Xiaofeng  Chen  Lanzhen  Zhou  Jinhui  Wu  Liming  Li  Yi  Chen  Fang  Zhang  Jinzhen  Zhao  Jing 《Chromatographia》2012,75(3-4):165-168

Determination of the levels of 1-octacosanol is important in food stuff for the study of its pharmacological activities and health benefits. In this study, a novel, simple and fast internal standard method for the non-derivatization ultra-performance liquid chromatographic determination of 1-octacosanol in raw materials and health products was developed and validated based on evaporative light scattering detection. The linearity (r 2 > 0.998), recovery (99.1–100.2%, RSD <2.7%), intra- and inter-day precision (RSD <3.8%), limit of detection (1.0 mg/L), limit of quantification (2.2 mg/L) of the 1-octacosanol were determined. The method was successfully applied to nine real 1-octacosanol products. The results of analyses had close agreement with the labeled claims of 1-octacosanol content in these products. Compared with the classical gas chromatography method, the developed method was simpler, faster and more environmentally friendly due to avoiding any derivatization step. This protocol represents a rapid and feasible method for quality control of 1-octacosanol products.

  相似文献   
949.
基于Goetschel-Voxman所定义的序关系(Goetschel Jr R,Voxman W.Elementaryfuzzy calculus.Fuzzy Sets and Systems,1986,18:31-43),讨论了模糊数值函数的可微性,并利用梯度讨论了定义在n-维空间上的无约束条件模糊规划的最优性条件以及有约束条件的模糊规划取得最优解的必要条件—Kuhn-Tucker条件.同时,对于凸模糊规划问题,给出了其取得最优解的充分条件和算例.  相似文献   
950.
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