蚯蚓对土壤中杀虫剂的回避行为——一种用于土壤健康质量快速诊断的装置和方法

通过设计一套试验装置,研究了蚯蚓对土壤中杀虫剂的回避行为。结果显示,蚯蚓对某些杀虫剂非常敏感,土壤中杀虫剂含量达到其半致死浓度(LC50)的1/5～1/25时,即出现明显的逃逸或迁移行为。

WEPP模型的最新研究进展

WEPP(Water Soil Loss Equation)作为新一代水蚀预报模型,是指导水土保持措施优化配置、水土资源保护与持续利用的有效工具。近年来,遥感和GIS技术为WEPP快速获取所需资料、处理数据、图像编辑和输出等提供可靠的技术支撑;同时,区域化、尺度概念的引入,为WEPP应用于大尺度提供技术保障。为借鉴WEPP模型的优点,促进我国水蚀预报模型的发展,对WEPP模型的最新发展进行了详尽的介绍,并对WEPP应用到我国时可能存在的问题进行了初步分析。

施氮对大豆根系形态和氮素吸收积累的影响

采用框栽试验方法研究了不同施氮水平对大豆根系形态和氮素吸收积累的影响,结果表明:不同施氮水平对大豆植株生物量、氮素吸收积累量及根系形态有显著影响,随施氮量增加,植株干重、氮素积累量、单株产量等均呈先增加后降低趋势,其中以N100[100kg(N)·hm-2]处理效果最佳,总体表现为N100>N200>N50>N25>N0。无N(N0)和适量偏低的氮(N25、N50)增加了大豆的根冠比,但过多的氮(N200)反而降低了大豆的根冠比,说明低氮胁迫促进了大豆根系的生长。大豆根长、根表面积和根体积随施氮量的增加表现为先降后增而后又降低的规律,不施氮(N0)情况下,根长、根表面积和根体积均高于低氮处理(N25、N50),之后随施氮量增加而增加,当超过一定施氮量(N200)时又呈降低趋势。不同生育时期植株生物量、氮素积累、根长、根表面积和根体积等表现为花期>苗期>鼓粒期。因此施用一定量氮肥对大豆植株生物量、氮素积累以及根系形态等产生显著影响,进而影响大豆氮素转运量和转运效率,最终影响大豆籽粒产量和品质。

新疆三工河流域尾闾绿洲地下水变化与土壤积盐的响应

研究地下水动态和土壤积盐过程有助于了解地下水抬升对土壤积盐的作用规律,合理利用水资源,防止土壤盐渍化。根据1985年、2000年和2005年的地下水等值线图资料,结合研究区1983~2005年水资源利用和0~20cm土壤层总盐数据以及土地利用数据,利用GIS技术和地统计学方法,分析了近23a来地下水动态,以及地下水抬升与地表积盐的关系。结果表明:区域输水灌溉是地下水水位抬升的直接动因。年均地下水水位抬升0.09m,地下水位每抬升1m,造成区域地表积盐区增加144.45hm2,地下水位的抬升对区域灌溉景观的积盐面积的扩张作用要强于非灌溉景观,在灌溉景观中耕地积盐速率最快,达0.43t.hm-.2a-1,23a间,单位面积的积盐量增加了40.04%,在非灌溉景观中,盐碱地的积盐作用较强,积盐速率达0.68.thm-.2a-1。

气象要素空间化方法精度的比较研究:以平均气温为例

以国家气象局1971年~2000年30年整编资料中的东北、华中地区1978年、1984年、1990年、1996年4年的1月份、7月份及年平均气温数据为数据源,采用直接插值法(反距离权重法和普通克里格法)、趋势面模拟+残差内插法、空间化气候值+年际距平空间插值方法、空间化气候值+年际距平趋势面模拟+残差内插等4种方法,进行了空间化精度的比较研究。通过平均绝对误差(MAE)、平均相对误差(MRE)以及交叉验证等几种评估标准的比较,认定在具有30年月平均气温栅格数据库作为背景的前提下,采用空间化气候值+年际距平

Constructing porous frameworks from one-dimensional cobalt-oxygen clusters and pyridinedicarboxylate ligands adopting two rare coordination modes

A porous material with cobalt-oxygen cluster framework has been synthesized hydrothermally, which possesses large and rigid channels and manifests strong antiferromagnetic interactions, and the pyridinedicarboxylate ligand exhibits two types of rare coordination modes.

Ethylene polymerization, and the copolymerizations of ethylene with hexene or norbornene with highly active mono(beta-enaminoketonato) vanadium(III) catalysts

Five novel vanadium(III) complexes [PhN = C(R-2)CHC(R-1)O]VCl2(THF)(2) (4a: R-1 = Ph, R-2 = CF3; 4b: R-1 =t-Bu, R-2 = CF3; 4c: R-1 = CF3, R-2 = CH3; 4d: R-1 = Ph, R-2 = CH3; 4e: R-1 = Ph, R-2 = H) have been synthesized and characterized. On activation with Et2AlCl, all the complexes, in the presence of ethyl trichloroacetate (ETA) as a promoter, are highly active precatalysts for ethylene polymerization, and produce high molecular weight and linear polymers. Catalyst activities more than 16.8 kg PE/mmolv h bar and weight-average molecular weights higher than 173 kg/ mol were observed under mild conditions.

Diarylmethylene-bridged 4,4 '-(bis(9-carbazolyl))biphenyl: morphological stable host material for highly efficient electrophosphorescence

novel compound (BCBP) based on the modification of a well-known host material 4,4'-(bis(9-carbazolyl))biphenyl (CBP) through arylmethylene bridge linkage was synthesized, and fully characterized. Its thermal, electrochemical, electronic absorption and photoluminescent properties were studied. A high glass transition temperature (T-g) of 173 degrees C is observed for BCBP due to the introduction of the bridged structure, remarkably contrasting with a low T-g of 62 degrees C for CBP. Furthermore, the bridged structure enhances the conjugation and raises the HOMO energy, thus facilitating hole-injection and leading to a low turn-on voltage in an electroluminescent device. With the device structure of ITO/MoO3/NPB/Ir complex: BCBP/BCP/Alq(3)/LiF/Al, maximum power efficiencies of 41.3 lm/W and 6.3 lm/W for green- and blue-emitting OLED were achieved, respectively.

水基导电聚苯胺/二氧化硅杂化材料的防腐性能研究

利用羧基同导电聚苯胺(cPANI)主链上的氮原子的相互作用,制备了静电作用型水基导电聚苯胺/二氧化硅杂化材料,研究了杂化材料涂层对冷轧钢板的防腐性能.在3.5%NaCl中,含11 wt%cPANI的杂化材料涂层的腐蚀电位比纯二氧化硅涂层正移了200 mV,腐蚀电流从13.4μA降到2.4μA,下降了5倍,表明含cPANI的静电作用型杂化涂料使冷轧钢板表面变得更惰性.阻抗分析结果表明,cPANI含量为11 wt%的静电作用型杂化材料的阻抗比纯无机二氧化硅涂层大一个数量级,而且在碱性介质中浸泡10天后,杂化材料涂层的阻抗仍然保持稳定,而纯无机二氧化硅涂层的阻抗比初始值下降了一个数量级.杂化材料的形态分析结果表明,cPANI在静电作用型cPANI/二氧化硅杂化材料中的分布比在普通cPANI/二氧化硅杂化材料中更加均匀一致,从而使得它比普通的cPANI/二氧化硅杂化材料具有更好的防腐效果.

Folate-Conjugated Micelles and Their Folate-Receptor-Mediated Endocytosis

A folate-conjugated copolymer PEG-PLA-PLL/folate was synthesized and mixed with pure PEG-PLA-PLL and a fluorescent model drug mFITC to prepare folate-conjugated micelles. The distribution of micelles was studied on cancer-cell-bearing mice via frozen slicing. The results show that mFITC is successfully encapsulated into folate(+) and folate(-)micelles; PEG-PLA-PLL micelles the latter can be internalized by both HeLa and CHO cells without selectivity due to their cationic surface charges, while folate(+)micelles exhibit more preferential endocytosis by HeLa cells than by CHO cells. The folate(-)micelles showed retention in both organs and tumors. The folate(+)micelles are a promising active targeting drug delivery system for FR over-expressing cells and they accumulate in tumor beds.

Synthesis, structure and optical properties of new organic-inorganic haloplumbates complexes (C5H10N3)PbX4 (X = Br, Cl), (C2H2N4)PbBr3

Layered organic-inorganic composite materials (C5H10N3)PbX4 (X = Br 1, Cl 2) containing histaminium dications were grown via a solution-cooling process, and their structure and optical properties were determined. The organic ligand-histaminium introduced into the corner-sharing octahedra of the 'PbX4- layer' contains both primary ammonium and imidazolium different from the traditionally primary amine found in this system. As comparison, another analogous amine of 3-amino-1,2,4-triazol was used as ligand to coordinate with PbBr2 in acid solution. A novel complex (C2H2N4)PbBr3 (3) was obtained with zigzag PbBr2 chains different from the PbX4 layer in compound as 1 and 2. The hybrid (C5H10N3)PbX4 show exciton absorption at 339 nm for X = Cl and 419 nm for X = Br with the corresponding emission at 360 and 436 nm, respectively. The different PbBr2 chain structure of compound 3 does not show photo luminescence.

Surface-modified Nafion (R) membrane by casting proton-conducting polyelectrolyte complexes for direct methanol fuel cells

Surface-modified Nafion (R) membrane was prepared by casting proton-conducting polyelectrolyte complexes on the surface of Nafion (R). The casting layer is homogeneous and its thickness is about 900 nm. The proton conductivity of modified Nafion (R) is slightly lower than that of plain Nafion (R); however, its methanol permeability is 41% lower than that of plain Nafion (R). The single cells with modified Nafion (R) exhibit higher open circuit voltage (OCV = 0.73 V) and maximal power density (P-max = 58 mW cm(-2)) than the single cells with plain Nafion (R) (OCV = 0.67 V, P x = 49 mW cm-2). It is a simple, efficient, cost-effective approach to modifying Nafion (R) by casting proton-conducting materials on the surface of Nafion (R).

Structural determination of a new phase of monoclinic BaTb2Mn2O7

A new phase of monoclinic BaTb2Mn2O7 with extra superlattice lines in addition to the usual orthorhombic X-ray diffraction patterns was prepared and a Rietveld refinement was applied to analyze the crystal structure using X-ray powder diffraction data at room temperature. The refined lattice parameters were a = 0.54918(8) nm, b = 2.0149(5) nm, c = 0.54922(9) nm, and beta = 90.62degrees with the space group A2/m (no. 12). The MnO6 oxygen octahedron has distortion and tilts around a-axis by about 7degrees each other in the reverse direction.