广州市住宅室内外大气羰基化合物的监测分析

选择代表性住宅,在其室内、外同步开展大气羰基化合物的监测分析,准确评价大气羰基化合物的污染状况,揭示其来源。用涂覆2,4-硝基苯肼(DNPH)的硅胶采样管收集羰基化合物,借助高效液相色谱完成样品分析,共检测了13种羰基化合物,其中甲醛、乙醛两种物质的平均浓度最高,占被测物质总浓度的30%~67%。甲醛、乙醛的浓度,夏季室内平均为53.47μg/m3、17.81μg/m3,室外平均为15.00μg/m3、10.97μg/m3;冬季室内平均为37.97μg/m3、11.49μg/m3,室外平均为10.44μg/m3、8.15μg/m3。大气羰基化合物呈现夏季高于冬季、室内大于室外的浓度变化规律。甲醛/乙醛和乙醛/丙醛比值结果反映城市大气羰基化合物的人为污染。     

Periodic solutions of Wick-type stochastic Korteweg–de Vries equations

Nonlinear stochastic partial differential equations have a wide range of applications in science and engineering. Finding exact solutions of the Wick-type stochastic equation will be helpful in the theories and numerical studies of such equations. In this paper, Kudrayshov method together with Hermite transform is implemented to obtain exact solutions of Wick-type stochastic Korteweg–de Vries equation. Further, graphical illustrations in two- and three-dimensional plots of the obtained solutions depending on time and space are also given with white noise functionals.     

有机小分子发光材料与聚合物发光材料在大气存放条件下的稳定性对比研究

分别采用紫外光电子能谱（UPS）、X光电子能谱（XPS）、原子力显微镜（AFM）、以及光致发光光谱（PL）等方法对在大气存放条件下的8－羟基喹啉铝（Alq)薄膜和聚（9,9－二辛烷基芴）（PFO）薄膜的电子结构、表面形 及发光特性进行了对比。研究结果表明,PFO的电子结构、表面形貌以及发光特性受外界气氛影响极小,是一种非常稳定的聚合物发光材料。这为聚合物发光器件的稳定性提供了有利的条件。     

Prolongation Approach to the Liouville Equation and Its Algebraic Structures

The Riccati type equation, the Biicklund transformation and the Lax pair of the Liouville equation are obtained by using the prolongation theory. It is shown that the prolongation structures generate the SL(2,R) Lie algebra.     

The Properties of Surface Polaron in the Semi-Infinite Polar Crystal

The effective Hamiltonian and the renormalized mass of surface polaron, where the electron is strongly coupled with the surface optical (SO) phonons but weakly or intermediately coupled with the bulk longit udinal-optical (LO) phonons, were first reviewed. The self-energy and the renormalized mass of the polaron for the polar crystals of potassium iodide, silver chloride and silver bromide are evaluated as a function of the depth Gom the crystal surface. Results of our calculation indicate that the effect of the electron-SO phonon interaction is dominant only within a very small layer from the crystal surface. Its justification awaits further experimental results.     

Regioselective Formation of Enediynes via Intramolecular Trapping of Allylic Cations

Enediynes are a novel class of naturally occurring antitumor antibiotics capable of causing DNA strand cleavage by hydrogen atom abstraction from the deoxyribose backbone. During the past decade, numerous synthetic methods have been developed to synthesize the naturally occurring and the "designed" enediynes for biomedical studies. Recently, we have succeeded in assembling the cis-enediynes 2 by a novel and high-yielding allylic rearrangement under mild reaction conditions (Eq 1).^1-3 This methodology has been used to synthesize a 10-membered ring enediyne³ which exhibits DNA cleavage activity.     

Preliminary Study on Destruction of Freon 12 by Inductively Coupled Plasma——Development of ICP Technology for Waste Destruction

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Quercetin enhances vitamin D2 stability and mitigate the degradation influenced by elevated temperature and pH value

Vitamin D₂ (vit. D₂) is a nutraceutical essentially needed for good health. However, it is susceptible to oxygen and high temperature. The use of natural products such as bioflavonoids possessing anti-degradative effect of vit. D₂ degradation has not been described before. A combinational effect of vit. D₂ with quercetin showed a positive effect and inhibited vit. D₂ degradation when exposed to high temperature (50 ℃ and 75 ℃) at different time points. The results obtained revealed vit. D₂ degradation was drastically increased with longer incubation under thermal treatment. However, quercetin and vit. D₂ groups were able to significantly inhibit the degradation of vit. D₂ and stabilize it, evaluated through the retention percentage. We also exposed vit. D₂ at solutions with different pH values (1, 4, 5, 7, 10). Quercetin exerted vit. D₂ anti-degradation at different pH values as well as under thermal pressure at different time points. Conclusively, quercetin can be an effective way to reduce temperature and pH induced degradation of vit. D₂.     

Enhanced Survivin siRNA Delivery Using Cationic Liposome Incorporating Fatty Acid-modified Polyethylenimine

We described a novel approach for survivin siRNA cellular delivery via a cationic liposome incorporating fatty acid-modified polyethylenimine. A linoleic acid derivative of branched polyethylenimine(PEI, M_w=25 kDa), PEI-LA, was synthesized and incorporated into the liposome. The properties of the liposome, cytotoxicity, cellular uptake of cancer cells for survivin siRNA, survivin protein downregulation levels were investigated. PEI-modified liposome showed a lower cytotoxicity and delivered survivin siRNA into HeLa cells and A549 cells efficiently compared with PEI-25kDa.     

锗酸锌锰荧光体发光学与荧光瞬态衰减研究

制备一系列锗酸锌锰荧光体,并探讨其发光特性、瞬态荧光衰减与色度值与所掺杂锰离子含量之间的相互关系.本系列荧光体锰离子发射峰波长,随Mn²⁺含量由0增加0.05,由527nm红移至534nm.实验表明这可能与Mn²⁺所占据的四面体格位,遭扭曲而导致晶场强度变弱有关.本系列荧光体的CIE色度坐标值,则随所掺杂Mn²⁺含量,仅有微小改变.锗酸锌锰荧光体瞬态荧光衰减的研究结果表明:锗酸锌基质的衰减生命期在纳秒范围;随Mn²⁺掺杂量增加,在毫秒范围的锰离子荧光衰减生命期逐渐缩短.此现象可能与Mn²⁺-Mn²⁺离子对中,Mn²⁺的自旋交换相互作用有密切关系.