侵蚀泥沙、有机质和全氮富集规律研究

在自然降雨下 ,研究降雨、坡度、耕作和施肥对侵蚀泥沙、有机质和全N富集率的影响 ,分析土壤和泥沙颗粒组成、富集与泥沙有机质和全N富集的关系 ,揭示土壤有机质和全N在泥沙中的富集规律 .结果表明 ,泥沙粘粒的富集导致有机质和全N的富集 ,泥沙粘粒、有机质和全N富集率分别平均为 1.77、2 .0 9和 1.61.土壤侵蚀模数与泥沙有机质和全N富集率呈显著的负相关关系 ,降雨、坡度、施肥和耕作措施对泥沙有机质富集作用的影响是通过减少土壤侵蚀模数来实现的 ,减少土壤侵蚀的措施可增加泥沙有机质和全N的富集 .

土壤中Frankia菌RNA提取

土壤中Ｆｒａｎｋｉａ菌ＲＮＡ提取王育英，林建群，郭秀荣，李彤，张忠泽（中国科学院沈阳应用生态研究所，１１００１５）Ｆｒａｎｋｉａ非亚科共生固氮是一类重要的固氮资源。对Ｆｒａｎｋｉａ共生生物学、生态学等特性曾进行过广泛的研究。８ｔ０年代末，Ｆｒａｎｋｉ...

微量添食对柞蚕蚁蚕抗逆性的影响

通过卵面微量添食葡萄糖、有益微生物 (EM)及CaCl2 3种物质 ,以半数致死时间 (LT50 )为指标 ,研究添食不同物质对柞蚕初孵蚁蚕抗逆性的影响。结果表明 ,卵面添食这 3种物质均能增强蚁蚕的抗低温能力 ,延长其在低温条件下的半数致死时间 (LT50 )。添食葡萄糖能显著延长蚁蚕对饥饿的LT50 ;添食EM能极显著延长蚁蚕对饥饿的LT50 ;添食CaCl2 对蚁蚕耐饥饿能力的影响不显著。各种添食物质对蚁蚕抗逆性的影响均存在浓度效应

植物与其它有机体的化学作用—潜在的有害生物控制途径

植物与其它有机体种间存在着通过次生物质为媒介的化学作用,这些化学作用在农业生态系统中则表现为植物对有害生物的化学防御。面对动物取食、微生物侵染和其它植物竞争,植物能合成释放特定的次生物质抵御侵害。而且,植物这种对有害生物的化学防御机制常常是在侵害条件下诱导产生的。当前的研究显示,作物/害虫/天敌三营养食物链也有自然的种间化学作用关系操纵,作物和杂草种间除了有相互抑制的化感作用外,还存在着通过次生物质进行的信息传递关系。揭示并充分利用植物这种内在的化学防御机制不仅能拓宽认识植物与其它有机体种间关系的视野,而且能开拓植物保护的新途径。

土地利用动态与风力侵蚀动态对比研究:以内蒙古自治区为例

内蒙古是我国土壤风力侵蚀较为严重的地区之一,同时也是我国土地利用方式剧烈变化的地区之一。依据两期土地利用数据以及相应年代的土壤风力侵蚀数据,研究了20世纪90年代末期内蒙古自治区土地利用和风力侵蚀的静、动态格局。根据土地利用和风力侵蚀的空间分布及动态变化特点,设计了内蒙古土地利用—风力侵蚀动态区划,基于该区划详细讨论了内蒙古不同地区占主导地位的土地利用动态与风力侵蚀动态,由此揭示了两者之间存在的驱动——被驱动关系。研究发现,在20世纪90年代末期,内蒙古土地利用和风力侵蚀的基本格局没有太大变化,但风力侵蚀强度在总体上增强了;土地利用的变化主要反映为草地的退化和耕地的扩张。土地利用动态与风力侵蚀动态有着良好的时空对应关系:草地的退化与耕地的扩张导致了显著的风力侵蚀增强,而草地的改善以及耕地的收缩对风力侵蚀的影响不如前者明显,这表明了土地利用动态对风力侵蚀动态正、反向驱动的不平衡性。

内蒙古呼伦贝尔市饮茶型氟铝联合中毒研究

目的探讨饮茶型氟中毒是否为砖茶型氟铝联合中毒。方法对饮茶型氟中毒病区进行饮水、砖茶、奶茶、主食、副食及牧民发、血、尿氟铝水平检测,对饮茶型氟中毒病区儿童和成人进行临床检查和拍摄X线片,同时对成人进行血液生物化学检查,以饮水型病区及非病区居民为对照组。结果呼伦贝尔市饮茶型病区饮水、主食、副食氟铝水平均在正常范围,砖茶氟铝水平分别为(541.3±48.8)、(4351±724)mg/kg,奶茶氟铝水平分别为(3.83±0.73)、(4.28±1.56)mg/L。饮水型病区饮水氟铝水平分别为(3.68±1.05)、(0.45±0.25)mg/L。饮茶型病区牧民氟总摄入量96.15%、铝总摄入量89.60%来源于砖茶。儿童氟斑牙检出率饮茶型病区为25.24%,饮水型病区为63.17%,饮茶型病区非常显著低于饮水型病区(P<0.01);成人氟中毒检出率饮茶型病区为42.61%,饮水型病区为28.83%,饮茶型病区显著高于饮水型病区(P<0.01)。结论呼伦贝尔市饮茶型氟中毒发病机理较为复杂,可能是砖茶型氟铝联合中毒。

Identification of Phenylethanoid Glycosides in Plant Extract of Plantago asiatica L. by Liquid Chromatography-Electrospray Ionization Mass Spectrometry

The present work describes a liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for rapid identification of phenylethanoid glycosides in plant extract from Plantago asiatica L. By using a binary mobile phase system consisting of 0.2% acetic acid and acetonitrile under gradient conditions, a good separation was achieved on a reversed-phase C-18 column. The [M-H](-) ions, the molecular weights, and the fragment ions of phenylethanoid glycosides were obtained in the negative ion mode using LC-ESI-MS. The identification of the phenylethanoid glycosides (peaks 1-3) in the extract of P. asiatica L. was based on matching their retention time, the detection of molecular ions, and the fragment ions obtained by collision-induced dissociation (CID) experiments with those of the authentic standards and data reported in the literature.

In Situ Preparation and Luminescent Properties of CeF3 and CeF3:Tb3+ Nanoparticles and Transparent CeF3:Tb3+/PMMA Nanocomposites in the Visible Spectral Range

CeF3 and CeF3:Tb3+ nanoparticles were prepared by reverse microemulsion with a functional monomer, methyl methacrylate (MMA), as the oil phase, and CeF3:Tb3+/poly (methyl methacrylate) (PMMA) nanocomposites were obtained via polymerization of the MMA monomer. The nanoparticles and nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), low- and high-resolution transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetric analysis (TGA), UV/vis transmission spectra, photoluminescence excitation, and emission spectra and luminescence decays. The well-crystallized CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 15 nm. They show the characteristic emission of Ce3+ 5d-4f (313 nm, D-2-F-2(5/2); 323 nm, D-2-F-2(7/2)) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 541 nm as the strongest one) transitions, respectively.

Synthesis, crystal structure, and thermal property of a novel supramolecular assembly: (NH42810424)(CHNO) O-[H(V)O(]2H)4(10)28(2), constructed from decavanadate and caffeine

A novel 3D supramolecular assembly constructed from decavanadate and caffeine building blocks, (NH4)(2)(C8H10N4O2)(4)[H4V10O28].2H(2)O (1), has been synthesized in aqueous solution and characterized by elemental analysis, IR, H-1 NMR, V-51 NMR, TG-DTA, and single crystal X-Ray diffraction. The compound 1 crystallizes in monoclinic system, space group P2(1)/n, a = 15.801(1) Angstrom, b = 12.914(1) Angstrom, c = 15.913(2) Angstrom, beta = 113.55degrees, V = 2976.4 (5) Angstrom(3), Z = 2, R = 0.0498 with 6818 reflections. Water molecules, ammonium ions, and caffeine act as "cement" linking the polyanions into 1D chain along the c-axis by hydrogen bonding. In compound 1, extensive hydrogen-bond contacts and strong pi-pi interactions lead to an ordered 3D supramolecular framework. TG-DTA curves indicate that the weight loss of the complex can be divided into three stages.

Synthesis of a new aryl ether ketone polymer

The synthesis of a new aryl ether ketone polymer with an advantageous ratio of glass transition temperature to melting temperature is reported.

Manipulation of electroosmotic flow in capillary electrophoresis for iodide and iodate

Manipulation of electroosmotic flow in capillary electrophoresis is an important step for separation of inorganic anions. The type. and concentration of electroosmotic flow modifier (OFM) exert a tremendous influence on the electroosmotic mobility. In the presence of CTAB as buffer solutions' pH values increase, the electroosmotic mobility becomes lower. At the same ionic strength, the buffer type affects the electroosmotic velocity and the migration order for iodide and iodate.