从实验数据看计算半衰期的理论

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

HIRFL辐照终端照射野均匀度与离子通量的关系

采用固体核径迹探测器聚碳酸脂膜,测定了兰州重离子研究装置提供的55MeV/u40Ar和80MeV/u20Ne离子束经辐照终端束流均匀化扫描装置后照射野均匀度与离子通量之间的关系.结果表明:对于40Ar和20Ne离子束,离子通量小于1×106和2×107ions/cm2时,横向照射野均匀度缓Ne离子束照射慢增加;当离子通量分别介于1×106—1×107和2×107—1×108ions/cm2时,40Ar和20野均匀度逐渐增加;离子通量达到1×107和1×108ions/cm2时,40Ar和20Ne离子束照射野均匀度分别约为58%和61%.从而说明,辐照终端束流扫描装置对束流的均匀化程度目前并不能满足辐照生物效应、辐射育种和重离子治癌等研究工作的需要,须对其性能做进一步的提高.

非全裸离子-原子碰撞中的多重电离研究

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

beta(+)/EC decay and systematic analysis of Ir-176,Ir-178

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.

Unified expressions of all integral variational principles

In terms of the quantitative causal principle, this paper obtains a general variational principle, gives unified expressions of the general, Hamilton, Voss, Holder, Maupertuis-Lagrange variational principles of integral style, the invariant quantities of the general, Voss, Holder, Maupertuis-Lagrange variational principles are given, finally the Noether conservation charges of the general, Voss, Holder, Maupertuis-Lagrange variational principles axe deduced, and the intrinsic relations among the invariant quantities and the Noether conservation charges of all the integral variational principles axe achieved.

GIS支持下的辽宁省地表水环境功能区划

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。

包膜与氢醌结合对尿素释放及水解的影响

通过探讨尿素和脲酶抑制剂氢醌被共同包被后二者在土壤中的溶出行为及其对尿素水解的控制,阐明此类肥料减缓尿素水解的机理,为此类肥料的开发和农业应用提供一定的理论依据。采用室内摸拟培养的方法开展:(1)尿素和脲酶抑制剂氢醌被共同包被后二者在土壤中的溶出行为。(2)添加氢醌尿素、包膜型尿素、尿素和脲酶抑制剂氢醌被共同包被后尿素在土壤中的水解特征。尿素和氢醌共包被肥料中尿素和氢醌的溶出高峰期同步,但氢醌从包膜中溶出的速率明显快于尿素;氢醌的添加减缓了尿素的水解进程,包膜型肥料释放到土壤中的尿素没有立即完全水解,而是发生了明显的水解滞后现象,但尿素水解速率的最大值明显高于尿素溶出速率的最大值,与包膜型肥料相比,尿素与氢醌共包被的尿素水解也有明显的滞后现象但其尿素水解速率的高峰值明显低于尿素溶出速率的高峰值;尿素在土壤中的水解速率决定性地影响着土壤pH的变化。包膜与氢醌的结合更加有效地控制了尿素的水解过程,尿素和氢醌的同时缓慢溶出使尿素的水解过程更加平缓,有效避免了尿素水解的激增现象,此种肥料的施用有利于减缓NH3的毒害及NH3的挥发损失。

On the propagation rate of the chemical waves observed during the course of CO oxidation on a Ag/Pt(110) composite surface

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.

长白山主要生态系统苔藓植物的多样性研究

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。

Seed germination and seedling morphology of the seagrass, Halophila engelmannii (Hydrocharitaceae)

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.

压力探针技术原理及其在植物水分关系研究中的应用

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。