混合菌固定化及其对土壤中芘和苯并芘的降解

从石油污染土壤中筛选出1株细菌(Bacillus sp.)和1株真菌(Mucor sp.),以12种不同材料为载体对混合菌进行固定化,研究了固定化混合菌的降解特性.结果表明,采用吸附法能有效实现混合菌在改性后蛭石上的固定化.制得的固定化混合菌,传质性能好,对芘(Pyr)和苯并芘(BaP)的降解率42 d分别可达94.96%和74.96%,明显高于游离菌对Pyr和BaP的降解率60.49%和50.09%.采用扫描电子显微镜(SEM)观察了固定化混合菌微观结构,同时探讨了固定化混合菌的传质过程

喀斯特地区景观变化分析——以贵州省普定县后寨河中下游地区为例

基于遥感和地理信息系统,应用景观分析软件,对贵州省普定县后寨河中下游1973～2004年的景观变化进行了研究。结果表明:研究区水田、旱地始终占据优势地位。景观类型面积变化中,有林地面积持续减少,旱地变化较复杂,草地、灌木林地、有林地三者之间双向转化明显,10.0°～17.5°,17.5°～25.0°,25°～35°3个坡度级的裸岩面积增加明显。景观整体呈现出人为的退耕还林还草、毁林毁草开荒与自然的生态系统逆向演替交互作用,处于波动状态。

functional monomers and polymers.CXXXVI.effect of metal ions on the interaction of synthetic nucleic acid analogs

The effect of metal ions on the conformation of thymine-containing poly-D-lysine was studied by CD spectra in aqueous solution. Of the metal ions studied,only copper(Ⅱ)ion affected the conformation of mucleic acid analogs .copper(Ⅱ)ion also affected the specifically interacting system made up of thymine-containing poly-D-lysine and polyadenylic acid.

辽河三角洲湿地区域生态风险评价

生态风险评价区别于生态影响评价的重要特征在于其强调不确定性因素的作用 ,区域生态风险评价相对于一般生态风险评价而言 ,其所涉及的风险源以及评价受体等都在区域内具有空间异质性 ,即具有区域分异现象 ,因而更具复杂性。以辽河三角洲湿地 (盘锦市 )为研究范围进行区域生态风险评价理论和方法的探讨。针对辽河三角洲主要生态风险源洪涝、干旱、风暴潮灾害和油田污染事故的概率进行了分级评价 ;并提出度量生态环境重要性和脆弱性的指标 ,分析了风险源的危害作用 ;运用遥感资料和地理信息系统 ( GIS)技术 ,完成了区域生态风险综合评价。

旱作高产田产量波动性和土壤干燥化

根据旱地作物长期田间试验数据 ,论述了旱作农业生产中作物产量波动性是一个规律性现象 ,并用波动系数加以表述。研究结果表明旱作高产田与低产田相比 ,存在相似的产量波动性 ,区别是它在较高产量水平上波动。高产田作物耗水量较高 ,从而导致土壤相对干燥化。土壤干燥化是高产田产量产生波动性的直接原因 ;而低产田则因作物吸水能力低 ,土壤储水不能充分利用所致

沈阳市东部土地利用格局变化

以沈阳市东部１９７６～１９８９年的历史航空像片为基础，以地理信息系统（ＧＩＳ）技 术为手段，分析土地利用的空间格局及其变化．结果表明，针叶林、水田平均嵌块体大小增 加，旱地、落叶林、灌丛平均嵌块体大小减少；分数维值略有增加．预示嵌块体形状逐步复 杂化；多样性指数、均匀性指数增加．优势度和蔓延度指数由原来的１．６３２７和８９．２０２２分 别减少到１．３２２６和８８．２７４４，说明景观嵌块体的空间分布趋于均匀，嵌块体的聚集分布状 况将随时间的推移逐步分散化．此外．本文对沈阳东部土地利用格局变化的原因进行了剖 析．

水肥耦合条件下春小麦叶片的光合作用

采用312-D最优饱和设计,在辽宁西部半干旱区进行了田间春小麦光合作用试验研究．结果表明:叶片光合速率与籽粒产量正相关．水肥单因子对叶片光合速率影响的大小顺序是,氮>水>磷．交互耦合作用对叶片光合速率影响的大小顺序为:氮与水耦合>氮与磷耦合>磷与水耦合．水肥耦合促进叶片光合速率提高的主要原因是:扩大了叶面积、提高了叶片蒸腾速率、增大了叶片气孔导度、提高了胞内水浓度、降低了胞内二氧化碳浓度．单叶光合速率高于7．5×10-3μmol／s的水肥优化管理方案是:施氮量为323．4-399．9 kg／hm2、施磷量为65．8-105．7 kg／hm2、灌水量为276．1-353．2 mm．

区域创新系统研究的进展及展望

区域发展的传统影响因素的作用正在减弱,区域科技创新对区域经济发展的重要影响正在增强。作为区域发展的重要影响因素,区域创新系统成为重要的研究方向。国内外学术界对区域创新系统的内涵、地位与作用等问题进行了深入研究,提出了一系列重要研究成果。针对目前学术界正在开展的科技创新的区域作用与影响、区域创新系统的发展等方面的研究进展进行归纳综述,并对有关研究工作的发展进行展望。

Preparation and Luminescence Properties of Gd2MoO6:Eu3+ Nanofibers and Nanobelts by Electrospinning

Gd2MoO6:Eu3+ nanofibers and nanobelts have been prepared by a combination method of the sol-gel process and electrospinning. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy, photoluminescence, and low voltage cathodoluminescence as well as kinetic decays were used to characterize the resulting samples. The results of XRD and FTIR indicate that the Gd2MoO6:Eu3+ samples have crystallized at 600 degrees C with the monoclinic (alpha) structure. The SEM and TEM results indicate that the as-formed precursor fibers and belts are uniform and that the as-prepared nanofibers and nanobelts consist of nanoparticles. Gd2MoO6:Eu3+ phosphors show their strong characteristic emission under UV excitation (353 nm) and low voltage electron-beam excitation (3 kV), making the materials have potential applications in fluorescent lamps and field-emission displays.

Synthesis and Spectrum of Novel Pyrazoline Fluorescent Compounds

Pyrazoline derivatives have been used widely in dyeing industry as fluorescent whitening agents due to their excellent capability. According to Schellhammer theory of the relation between chemical structure and fluorescent quality, six new fluorescent compounds were designed and synthesized which contained the benzothiazole group in the I-pyrazoline, the indole group in the 3-pyrazoline and the derivatives of phenyl in the 5-pyrazoline. The structure of target compounds was confirmed by IR, H-1 NMR, MS and elementary analysis. The fluorescence spectra showed that these compounds had good fluorescence. They could absorb ultraviolet light at near 353 nm. The fluorescence maximum emission wavelengths were about 430-443 nm. It was a kind of promising fluorescence compounds. The largest fluorescence emission wavelength and the fluorescence intensity were related to the substituted group of the compounds. When the 6-Br group was introduced into benzothiazole, the fluorescence emission wavelength exhibited a blue shift, and the fluorescence intensity increased.

Syntheses and properties of polyimides derived from diamines containing 2,5-disubstituted pyridine group

A Series of novel homo- and copolyimides containing pyridine units were prepared from the heteroaromatic diamines, 2,5-bis (4-aminophenyl) pyridine and 2-(4aminophenyl)-5-aminopyridine, with pyromelltic dianhydride (PMDA), and 3,3',4,4'-biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two-step thermal imidizaton method. The poly(amic acid) precursors have inherent viscosities of 1.60-9.64 dL/g (c = 0.5 g/dL in DMAC, 30 degrees C) and all of them can be cast and thermally converted into flexible and tough polyimide films. All of the polyimides show excellent thermal stability and mechanical properties. The polyimides have 10% weight loss temperature in the range of 548-598 degrees C in air. The glass transition temperatures of the PMDA-based samples are in the range of 395-438 degrees C, while the BPDA-based polyimides show two glass transition temperatures (T(g)1 and T(g)2), ranging from 268 to 353 degrees C and from 395 to 418 degrees C, respectively. The flexible films possess tensile modulus in the range of 3.42-6.39 GPa, strength in the range of 112-363 MPa and an elongation at break in the range of 1.2-69%. The strong reflection peaks in the wide-angle X-ray diffraction patterns indicate that the polyimides have a high packing density and crystallinity.

Isothermal crystallization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Isothermal crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was investigated by means of differential scanning calorimetry and polarized optical microscopy (POM). The Avrami analysis can be used successfully to describe the isothermal crystallization kinetics of PHBV, which indicates that the Avrami exponent n = 3 is good for all the temperatures investigated. The spherulitic growth rate, G, was determined by POM. The result shows that the G has a maximum value at about 353 K. Using the equilibrium melting temperature (448 K) determined by the Flory equation for melting point depression together with U-* = 1500 cal mol(-1), T-infinity = 30 K and T-g = 278 K, the nucleation parameter K-g was determined, which was found to be 3.14+/-0.07 x 10(5) (K-2), lower than that for pure PHB. The surface-free energy sigma = 2.55 x 10(-2) J m(-2) and sigma(e) = 2.70+/-0.06 x 10-2 J m(-2) were estimated and the work of chain-folding (q = 12.5+/-0.2 kJ mol(-1)) was derived from sigma(e), and found to be lower than that for PHB. This implies that the chains of PHBV are more flexible than that of PHB.