50 resultados para Vasari, Giorgio, 1511-1574.
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通过季节性观察 ,系统地研究了长白山阔叶红松林昆虫类群及其多样性 .结果表明 ,长白山阔叶红松林已知的森林昆虫 2 6目 131科 116 2属 196 0种 ,其中森林害虫 11目 10 5科 881种、重要森林害虫6 38种 ;森林昆虫群落中植食性昆虫类群总数所占比重最大 ,天敌昆虫群落中以捕食性类群总数所占比重最大 .植食类群、寄生性类群和捕食类群全年的均匀度指数分别为 0 884、0 830和 0 80 6 .各类群间季节变动系数的大小顺序为捕食类群 >寄生性类群 >植食类群 .
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提出了低价林早期诊断的新思路 ,即根据低价林的形成规律 ,在林分还未表现出低价林状况时就能诊断出其发展趋势 ,以便及时采取相应的经营管理措施 .以辽西油松林为例 ,从生态因子途径开展了低价林的早期诊断研究 ,建立了基于单因素实验和判别分析的生态因子途径早期诊断技术 .研究表明 ,土层厚度X1、有机质含量X2 、土壤全氮含量X3 、土壤含水率X4、土壤微生物总数量X5可选择作为油松低价林早期诊断的敏感指标 ;在综合诊断时引入了判别分析的数量分类方法 ,并根据判别分析的思路建立了油松林生长状况生态因子途径早期诊断方法 ,其步骤 :1)确定判别指标 ;2 )建立判别函数Y =1.5 96X1-0 .5 1X2 - 3.196X3 +1.6 2 2X4+1.898X5;3)通过判别函数和研究对象的各项判别指标值进行早期诊断 .低价林早期诊断的技术与方法尚有待进一步地研究、检验和完善 .
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采用层次分析法和综合指标法对辽宁省生态系统服务重要性进行了定量评价,分析了辽宁省生态系统生物多样性保护、水源涵养、土壤保持、沙漠化控制和营养物质保持重要性及其空间分布特征,在此基础上进行了辽宁省生态系统服务重要性及其区域分异规律的综合评价。结果表明:辽宁省生态系统服务均处于比较重要以上;其中极重要地区比重最大,占全省国土面积的60.66%;中等重要地区比较多,占全省国土面积的37.01%;其它少数地区为比较重要地区,占全省国土面积的2.33%。
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对沈阳市郊区农业景观中的秋菜田斑块的大小、形状及与其它斑块或廊道的邻接情况等基本特征进行了典型调查 ,分析和讨论了菜田斑块在该景观中的镶嵌特征 .在距城区约 5km以内的近郊区 ,许多秋菜田斑块相互邻接 ,并与各类公路相邻接 ;距城区 5~ 10km的中郊区 ,许多秋菜田斑块与玉米田斑块相邻接 ,并与乡村道路相邻接 ;在距城区 10km以上的远郊区 ,多数秋菜田斑块被玉米田斑块所包围 ,并与乡村道路相邻接 .
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通过监测不同培养条件下(灭菌、加选择抑菌剂、未灭菌)土壤中乙草胺残留数量和培养期间微生物标识物磷脂脂肪酸(PLFAs)含量的变化,探讨了以田间推荐量施用乙草胺时,不同微生物群落对乙草胺降解的相对贡献以及乙草胺对黑土微生物群落结构的影响.结果表明:乙草胺易于被微生物降解,其中,细菌对乙草胺的降解作用显著大于真菌,而真菌对乙草胺有更强的耐受能力.施入乙草胺后,各磷脂脂肪酸数量发生了显著变化,C14∶0、C16∶0和C18∶0所指示的土壤微生物量均有所下降;细菌PLFAs数量在培养初期显著降低,而后与对照的差异显著减小,表明细菌活性随着乙草胺的降解有所恢复;在施用乙草胺后的整个培养过程中,土壤真菌PLFAs数量始终低于对照,暗示着乙草胺对真菌的抑制可能是长期而不可逆的.
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Mg-3Al-0.5Mn-0.5Zn-1MM alloy was prepared by metal mould casting method. The as-cast ingot was homogenized and then hot-rolled at 673 K with total thickness reduction of 65%. Microstructure and mechanical properties of the as-cast and hot-rolled samples were investigated. The results showed that the as-cast sample mainly consisted of alpha-Mg, beta-Mg17Al12, Al10Ce2Mn7, and Al11RE3 (RE = La and Ce) phases. The average grain size of the sample homogenized at 673 K was about 240 gm, and it was greatly refined to about 7 mu m by dynamic recrystallization for the hot-rolled sample.
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A novel metal-organic framework with unprecedented interweaving of coaxial single-helical and equal double-helical chains of opposite chirality, which features a super-connective helix simultaneously tangling with eight helices, was reported.
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A new approach for the synthesis of polyaniline nanofibers under pseudo-high dilute conditions in aqueous system has been developed. High yield nanoscale polyaniline fibers with 18-110 nm in diameter are readily prepared by a high aniline concentration 0.4 M oxidation polymerization using ammonium persulfate (APS) as an oxidant in the presence of hydrochloric acid (HCl), perchloric acid (HClO4), (1S)-(+)-10-camphorsulfonic acid (CSA), acidic phosphate PAEG120 (PA120) and sulfuric acid (H2SO4) as the dopants. The novel pathway always produces polyaniline nanofibers of tunable diameters, high conductivity (from 10(0) to 10(1) S/cm) and crystallinity.
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Copolymerizations of ethylene with 5-vinyl-2-norbornene or 5-ethylidene-2-norbornene under the action of various titanium complexes bearing bis(beta-enaminoketonato) chelate ligands of the type, [(RN)-N-1=C(R-2)CH=C(R-3)O](2)TiCl2 (1, R-1=Ph, R-2=CF3, R-3=Ph; 2, R-1=C6H4F-p, R-2=CF3, R-3=Ph; 3, R-1=Ph, R-2=CF3, R-3=t-Bu; 4, R-1=C6H4F-p, R-2=CF3, R-3=t-Bu; 5, R-1=Ph, R-2=CH3, R-3=CF3; 6, R-1=C6H4F-p, R-2=CH3 R-3=CF3), have been shown to occur with the regioselective insertion of the endocyclic double bond of the monomer into the copolymer chain, leaving the exocyclic vinyl double bond as a pendant unsaturation. The ligand modification strongly affects the copolymerization behaviour. High catalytic activities and efficient co-monomer incorporation can be easily obtained by optimizing the catalyst structures and polymerization conditions.
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目的:研究中药羚羊角及其类似品中水溶性蛋白组分差异及鉴定方法,为其药效组分质量评价体系的建立提供科学数据。方法:采用紫外分光光度法(UV)和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)技术,对羚羊角及其类似品山羊角和黄羊角进行水溶性蛋白质含量和组分对比分析。结果:羚羊角中水溶性蛋白的含量高于黄羊角和山羊角,且3种角类中药蛋白组分的组成差异显著。结论:蛋白组分可用于羚羊角的鉴定,采用药效蛋白组分评价角类中药质量具有明显的科学性和实用性。
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A new solid solution series, NdSr(1-x)M(x)NiO(4) (M = Ca: 0.0 less than or equal to x less than or equal to 1.0; M = Ba: 0.0 less than or equal to x less than or equal to 0.6), was synthesized by solid state reaction, and the structures, magnetic and electrical properties and optical spectra of this series have been studied. All the samples crystalized in tetragonal systems, with the exception of NdCaNiO4, which crystallized in the orthohombic system. IR spectra of NdSr1-xCaxNiO4 indicated that the lengths of two Ni-O bonds decrease with increasing Ca content. The electrical conduction changed from metallic-type to semiconductive-type when x greater than or equal to 0.4 (M = Ca, Ba), and the room temperature resistivities of NdSr1-xCaxNiO4 increased with the increase of Ca content. Magnetic susceptibility measurements revealed that Ni+3 ions in all the samplies were in low-spin state over the temperature range 77-300 K.
Cytoglobosins A-G, Cytochalasans from a Marine-Derived Endophytic Fungus, Chaetomium globosum QEN-14
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Financial support from the Ministry of Science and Technology of China (2010CB833802 and 2007AA09Z446) and from the National Science Foundation of China (30910103914) is gratefully acknowledged.