辽北农田土壤农药残留特征及其对农产品安全影响

农药对产地环境，特别是对土壤的广泛污染严重威胁农产品安全和人类健康。因此，本文采用建立的除草剂和有机氯农药（OCPs）残留分析方法，开展了辽北地区土壤农药残留特征、阿特拉津和乙草胺田间消解动力学、土壤农药残留对农产品安全影响等方面研究。主要研究结果如下： 1. 分别建立了土壤、大米、蔬菜、玉米中3种除草剂和8种OCPs多残留分析方法。方法检出限介于0.04~1.30 ng•g-1之间；11种农药在0.01 (0.02)~1.0 (2.0) mg•L-1范围内线性良好，相关系数介于0.9963-0.9998之间；平均回收率介于71%-117%之间、相对标准偏差小于14.4%。 2. 阿特拉津和乙草胺在辽北农田土壤普遍残留；丁草胺、六氯苯、狄氏剂和艾氏剂在部分土壤有残留；乙草胺和丁草胺相对其它农药残留较高；阿特拉津、六氯苯、狄氏剂和艾氏剂残留量与相关报道和标准相比较低。除艾氏剂外，检出农药残留量经Box-Cox变换后，均服从正态分布。阿特拉津、乙草胺、丁草胺、六氯苯在不同土壤利用类型之间存在显著差异（P<0.05）。 3. 玉米地土壤中阿特拉津和乙草胺消解动态符合一级反应动力学模式，阿特拉津消解半衰期在12.2~59.8d之间，乙草胺在18.5~54.6d之间。喷施地阿特拉津和乙草胺消解速率约为对照地的2~5倍，且喷施量越大，消解越快。 4. 11种农药在辽北蔬菜、大米、玉米中残留较低，仅阿特拉津、六氯苯、乙草胺和丁草胺在部分农产品中有残留，其在土壤中残留通过蔬菜、大米和玉米给消费者带来的总膳食风险较低。大田试验进一步说明在试验区域喷施4倍最大推荐剂量阿特拉津或乙草胺也不会对玉米安全产生影响。

The Development of a Marine Natural Product-based Antifouling Paint

Problems with tin and copper antifouling compounds have highlighted the need to develop new environmentally friendly antifouling coatings. Bacteria isolated from living surfaces in the marine environment are a promising source of natural antifouling compounds. Four isolates were used to produce extracts that were formulated into ten waterbased paints. All but one of the paints showed activity against a test panel of fouling bacteria. Five of the paints were further tested for their ability to inhibit the settlement of barnacle larvae, Balanus amphitrite, and algal spores of Ulva lactuca, and for their ability to inhibit the growth of U. lactuca. Two paints caused a significant decrease in the number of settled barnacles. One paint containing extract of Pseudomonas sp. strain NUDMB50-11, showed excellent activity in all assays. The antifouling chemicals responsible for the activity of the extract were isolated, using bioassay guided fractionation, and their chemical structures determined.

Nanocrystalline LaGaO3 : Tm3+ as an efficient blue phosphor for field emission displays with high color purity

Nanocrystalline Tm3+-doped LaGaO3 phosphors were prepared through a Pechini-type sol-gel process [M. P. Pechini, U.S. Patent No. 3,330,697 (11 July 1967)]. X-ray diffraction, field emission scanning electron microscopy, photoluminescence, and cathodoluminescence (CL) spectra were utilized to characterize the synthesized phosphors. Under the excitation of ultraviolet light and low voltage electron beams (0.5-3 kV), the Tm3+-doped LaGaO3 phosphors show the characteristic emissions from the LaGaO3 host lattice and the Tm3+ (D-1(2), (1)G(4)-F-3(4), and H-3(6) transitions), respectively. The blue CL of the Tm3+-doped LaGaO3 phosphors, with a dominant wavelength of 458 nm, had better Commission International I'Eclairage chromaticity coordinates (0.1552, 0.0630) and higher emission intensity than the commercial product (Y2SiO5:Ce3+).