994 resultados para 179


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IEECAS SKLLQG

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从实验数据衡量了粗糙理论、TDA和QRPA三种计算半衰期的理论 ,结果表明 ,QRPA理论最好

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利用加速器提供的非全裸重离子束 (q=1 - 4)轰击氦、氖和氩原子 ,研究了由非全裸离子引起原子多重电离的有效电荷效应和电荷交换效应 .提出用一个有效电荷来等价描述非全裸入射离子对靶原子的作用 ,将描述全裸离子 -原子碰撞过程的物理模型推广到处理非全裸离子 -原子碰撞过程 ,采用轨道贯穿模型对有效电荷的内在物理机制进行了解释 ,提出一种新的理论方法将多重电离中俄歇过程的贡献予以扣除 .通过研究发现 ,扣除俄歇过程贡献后 ,多重电离截面随入射离子q/ v的变化与多步过程的预言相符

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The gamma rays following the beta(+)/EC decay of Ir-176,Ir-178 nuclei have been investigated using in-beam gamma-ray experiment. In addition, with the aid of a helium-jet recoil fast tape transport system, the beta(+)/EC decay of Ir-176 was further studied, the new gamma rays were proved and a low-spin isomer was proposed in Ir-176. The isomeric state was analysized according to the systematics in neighboring nuclei.

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辽宁省现执行的地表水环境功能区划存在着环境功能与实际情况的差别,对水功能区目标期望值过高,难以适应当前环境管理需要。在GIS技术支持下,对辽宁省地表水环境功能进行了调整、核定和重新划分。建议将辽宁省地表水主要水系共划分781个水环境功能区,其中源头水域15个,自然保护区7个,饮用水源保护区204个,渔业用水区287个,景观娱乐用水区54个,工业用水区35个,农业用水区179个;采用基于组件的GIS开发技术,设计实现了辽宁省地表水环境功能区划信息系统,从而为辽宁省水环境功能区划信息管理、水资源保护及科学制定水环境管理方案提供决策支持。

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We have analyzed the propagation rate of the chemical waves observed during the course of CO oxidation on a Ag/Pt(I 10) composite surface that were reported in our previous papers [Surf Interface Anal. 2001, 32, 179; J. Phys. Chem. B 2002, 106, 5645]. In all cases, the propagation rate v can be adequately fitted as v = v(0) + D-0/d, in which v(0) and D-0 are constants, and d is the distance between the reaction front of the chemical wave and the boundary from which the chemical wave originates. We propose that the surface species responsible for the formation of the chemical wave comes from two paths: the adsorption of molecules in the gas phase on the surface and the migration from the adjacent surface with different catalytic activity. v(0) corresponds to the contribution from the surface species due to the adsorption, and D-0/d to that of the surface species that migrates from the adjacent surface. The rate equation clearly suggests that the observed chemical wave results from the coupling between adjacent surfaces with different catalytic activities during the course of heterogeneous catalysis. These results, together with our previous reports, provide a good fundamental understanding of spillover, an important phenomenon in heterogeneous catalysis.

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长白山地区共有苔藓植物65科179属437种,32个变种和亚种。其中,石生和岩面薄土生种类(saxicolous bryophyte)最丰富,其次为腐木生种类(saprophytic bryophyte)和树生种类(epiphytic bryophyte),再次为土生种类(soil and humus bryophyte)。沼泽地、水体等生境中的种类(peat, marsh and water bryophyte) 相对较少。地面生苔藓植物的物种丰富度以暗针叶林(dark conifer forest)最高,而多样性以落叶松-沼泽地(Larix olgensis-bogs)和暗针叶林为最高;腐木生苔藓植物的物种丰富度和多样性均以暗针叶林为最高,树附生苔藓植物的物种丰富度和多样性以暗针叶林以及红松阔叶混交林(Pinus koraiensis broad_leaved mixed forest) 与暗针叶林间的过渡林为最高。定性分析表明,海拔高度、林冠层郁闭度和林内湿度、土壤酸度、含水量、林下倒木的丰富程度等可能是影响本地区苔藓植物多样性的重要环境因子。

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Seeds of Halophila engelmannii Aschers., that were collected in Redfish Bay, Texas, at weekly intervals from mid-May to mid-June 1986, began to germinate 3–4 weeks after collection. Most of the collections subsequently showed an increase in the rate of germination under increased light intensity and all had a stoppage of germination after transfer to darkness, indicating a light requirement to break endogenous seed dormancy. During the 5 weeks after seeds germinated, seedlings in soil culture produced a rosette of six leaves before the appearance of a rhizome bud in the axil of the third leaf. The first node of the rhizome produced a root and an upright shoot with a pseudowhorl of three to five leaves.

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现代压力探针主要分为高等植物细胞压力探针、根压力探针、木质部压力探针和取样压力探针4个变种,并形成了相关的理论体系,广泛应用于植物生理学及其相关领域的研究中。现代压力探针技术不仅可用于高等植物细胞和组织水平水分关系、水和溶质的相互作用关系的研究,还可进行根木质部负压的测定及高等植物活体单细胞内含物的取样研究等。未来更可借助取样压力探针与微量分析技术的结合,将高等植物单细胞内的水分关系和代谢过程定量联系起来;或可试图拓宽木质部压力探针测定的压力范围,进一步研究和验证内聚力-张力学说的理论和机制。