土壤中重金属形态变化的试验研究

日本神通川流域因镉污染而发生的骨病病引起了各国的重视.据统计,我国目前受此污染的农田面积约20万亩,当地居民和家畜受到不同程度的危害.有的专家认为,在我国镉污染比其它重金属污染更为严重,因此有必要对其进行深入研究,为治理污染土壤提供依据

农村水塘系统对非点源水污染的调控作用研究

以辽阳市沙岭镇大闯屯村为例,对北方平原地区农村水塘系统污染现状、非点源污染物的迁移途径、控制方法进行了初步研究,研究结果表明,农田径流与村落生活污水的排放方式对农村地表水环境质量具有重要影响,进行合理的生态设计,充分利用自然净化单元,对改善地表水环境质量将会起到积极的作用。

日本阿波罗山国有林地降雨引起的滑坡研究

经对日本福冈县阿波罗山国有林地降雨引起的 31处滑坡的统计分析表明 ,每处滑坡的平均面积 91m2 ,平均泥沙量 98m3;就坡面坡度和形状比而言 ,滑坡发生的相对累积频率呈正态分布 ;就滑坡的面积和泥沙沉积量而言 ,滑坡发生的相对累积频率呈对数正态分布 ;93 5 %的滑坡发生在修建道路时形成的人工挖方或填方坡段 ,挖方坡比填方坡更易发生滑坡。 4 2 %的滑坡发生在凹坡 ,32 %发生在直坡 ,2 6 %发生在凸坡。径流流经地表裂隙两次以上的地点 ,引发滑坡危险性更大 ,发生频率达 4 5 2 %。

沙丁胺醇在家兔体内的时间药代动力学

沙丁胺醇（Ｓａｌ）抗哮喘作用的昼夜节律，可能与其在体内的药代动力学的昼夜差别有关。为此本文给家兔灌胃２ｍｇ·ｋｇ－１Ｓａｌ，用ＨＰＬＣ荧光检测１０：００ｈ和２２：００ｈ两个时间动物体内血药浓度。结果表明，Ｓａｌ的药动学参数存在明显的昼夜差别。Ｔｐ白天为（２．２８±０．２０）ｈ，夜间为（１．２５±０．３０）ｈ（Ｐ＜０．０５）；ＡＵＣ白天为（０．４１±０．０９）ｍｍｏｌ／Ｌ·ｈ，夜间为（０．３０±０．０５）ｍｍｏｌ／Ｌ·ｈ（Ｐ＜０．０５）；Ｔ１／２白天是（２．７２±０．２２）ｈ，夜间为（１．８６±０．１３）ｈ（Ｐ＜０．０５）；Ｃｍａｘ昼夜无差别。

远紫外辐射对紫杉幼苗针叶膜脂过氧化及内源保护系统的影响

实验室条件下用远紫外线 (UV BC)光源照射紫杉幼苗 ,随照射时间延长 ,针叶的离子渗出率、膜脂过氧化水平、组织自动氧化速率及H2 O2 含量显著增加 ,可溶性蛋白、抗坏血酸、类胡萝卜素和叶绿素含量下降 ,叶绿体光系统II电子传递活性显著下降 ,外源活性氧清除剂苯甲酸钠和抗坏血酸对针叶膜脂过氧化有抑制作用 ;甲基紫精和DDC对针叶膜脂过氧化有促进效果 ,远紫外线引起的紫杉伤害可能和针叶树的越冬光氧化伤害有类似之处 .紫杉苗对紫外辐射的抗性远高于一般农作物 .

Synthesis and Luminescent Properties of LaAlO3:RE3+ (RE = Tm, Tb) Nanocrystalline Phosphors via a Sol-Gel Process

LaAlO3:Tm3+ and LaAlO3:Tb3+ phosphors were prepared through a Pechini-type sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence, and cathodoluminescence (CL) spectra were utilized to characterize the synthesized phosphors. The XRD results reveal that the fully crystalline pure LaAlO3 Phase can be obtained at 800 degrees C. The FE-SEM image indicates that the phosphor samples are composed of aggregated spherical particles with sizes ranging from 40 to 80 nm. Under the excitation of ultraviolet light (230 nm) and low-voltage electron beams (1-3 kV), the LaAlO3:Tm3+ and LaAlO3:Tb3+ phosphors show the characteristic emissions of Tb3+ (D-1(2)-> H-3(6,4),F-3(4) transitions) and Tm3+ (D-5(3,4)-> F-7(6,5,4,3) transitions) respectively. The CL of the LaAlO3:Tm3+ phosphors have high color purity and comparable intensity to the Y2SiO5:Ce3+ commercial product, and the CL colors of Tb3+-doped LaAlO3 phosphors can be tuned from blue to green by changing the doping concentration of Tb3+ to some extent.

Phase transformation and photoluminescence properties of nanocrystalline ZrO2 powders prepared via the Pechini-type sol-gel process

Nanocrystalline ZrO2 fine powders were prepared via the Pechini-type sol-gel process followed by annealing from 500 to 1000 degrees C. The obtained ZrO2 samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), and photoluminescence spectra (PL), respectively. The phase transition process from tetragonal (T) to monoclinic (M) was observed for the nanocrystalline ZrO2 powders in the annealing process, accompanied by the change of their photoluminescence properties. The 500 degrees C annealed ZrO2, powder with tetragonal structure shows an intense whitish blue emission (lambda(max) = 425 nm) with a wide range of excitation (230-400 nm). This emission decreased in intensity after being annealed at 600 degrees C (T + M-ZrO2) and disappeared at 700 (T + M-ZrO2), 800 (T + M-ZrO2), and 900 degrees C (M-ZrO2). After further annealing at 1000 degrees C (M-ZrO2), a strong blue-green emission appeared again (lambda(max) = 470 nm).

Synthesis and chain-length dependent properties of monodisperse oligo(9,9-di-n-octylfluorene-2,7-vinylene)s

A series of monodisperse oligo(9,9-di-n-octylfluorene-2,7-vinylene)s (OFVs) with fluorene units up to 11 has been synthesized following a divergent approach. Chain length was found to affect not only photophysical properties but also thermal properties. Absorption and photoluminescence spectra are red-shifted with increasing chain length. The effective conjugated length has been extrapolated to be as long as 19 fluorene vinylene units, indicative of a well-conjugated system. With the number of fluorene units > 5, the oligomers exhibit nematic mesomorphism. Glass transition temperature (T-g) and clearing point temperature (T-c) increase with increasing molecular length and with those of OFV11 up to 71 and 230 degrees C, respectively. The oligomers can form uniform films by solution casting for fabrication of light-emitting diodes. With a device structure of ITO/ PEDOT:PSS/OFV11/Ca/Al, a current efficiency of 0.8 cd.A(-1) at a brightness of 1300 cd.m(-2) along with a maximum brightness of 2690 cd.m(-2) have been realized. This performance is notably superior to that of the corresponding polymer.

Synthesis, properties, and gas permeation performance of cardo poly(arylene ether sulfone)s containing phthalimide side groups

Novel bisphenol monomers (1a-d) containing phthalimide groups were synthesized by the reaction of phenolphthalein with ammonia, methylamine, aniline, and 4-tert-butylanilne, respectively. A series of cardo poly (arylene ether sulfone)s was synthesized via aromatic nucleophilic substitution of 1a-d with dichlorodiphenylsulfone, and characterized in terms of thermal, mechanical and gas transport properties to H-2, O-2, N-2, and CO2. The polymers showed high glass transition temperature in the range 230-296 degrees C, good solubility in polar solvents as well as excellent thermal stability with 5% weight loss above 410 degrees C. The most permeable membrane studied showed permeability coefficients of 1.78 barrers to O-2 and 13.80 barrers to CO2, with ideal selectivity. factors of 4.24 for O-2/N-2 pair and 28.75 for CO2/CH4 pair. Furthermore, the structure-property relationship among these cardo poly(arylene ether sulfone)s had been discussed on solubility, thermal stability, mechanical, and gas permeation properties. The results indicated that introducing 4-tert-butylphenyl group improved the gas permeability of polymers evidently.

均苯三甲酸铕发光配合物的合成与表征

在乙醇和水的混合溶剂中,合成了铕(Ⅲ) 均苯三甲酸(H3L)发光配合物。通过元素分析、化学分析、热分析和红外光谱确定其化学组成为[EuL(H2O)5]·H2O。X射线衍射分析结果表明配合物为晶体物质,由扫描电镜照片可以看出配合物为棒状物质,晶粒大小10～20μm,荧光光谱分析结果表明配合物在紫外光激发下发出红色的荧光。

Annealing effects on the surface morphologies of thin PS/PMMA blend films with different film thickness

The surface morphology evolution of three thin polystyrene (PS)/polymethyl methacrylate (PMMA) blend films (<70 nm) on SiOx substrates upon annealing were investigated by atomic force microscopy (AFM) and some interesting phenomena were observed. All the spin-coated PS/PMMA blend films were not in thermodynamic equilibrium. For the 67.1 and the 27.2 nm PS/PMMA blend films, owing to the low mobility of the PMMA-rich phase layer at substrate surfaces and interfacial stabilization caused by long-range van der Waals forces of the substrates, the long-lived metastable surface morphologies (the foam-like and the bicontinuous morphologies) were first observed. For the two-dimensional ultrathin PS/PMMA blend film (16.3 nm), the discrete domains of the PS-rich phases upon the PMMA-rich phase layer formed and the secondary phase separation occurred after a longer annealing time.