998 resultados para Sujet âgé


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Medium-spin states of Ge-70 have been studied via the Ni-60(C-12,2p gamma)Ge-70 reaction at 45 MeV. The ground-state band and the second 0(+) band have been extended to the 12(+) and 8(+) states, respectively. Two negative-parity bands, one of which has a coupled structure and the other has a decoupled structure, have been observed additionally. Although the latter decoupled structure was known up to the (21(-)) state from a previous experiment, the part of the level scheme up to the 15(-) state has been largely modified by the present experiment. Backbendings observed in the positive- and negative-parity yrast bands have been compared with those of the neighboring even Ge isotopes. The experimental level structure has been compared with the shell-model calculations in the model space (2p(3/2), 1f(5/2), 2(p1/2), 1g(9/2)) employing two kinds of effective interactions, one of which is an extended P + QQ interaction with monopole interactions and the other is developed from a renormalized G matrix. Microscopic structures of the observed bands have been discussed with the help of the shell-model calculations.

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采用5台1.5W/4.2KG-M制冷机(日本住友RDK415D)并联研制出了1台方便实验室使用的小型氦液化装置,并为其建立了性能测量实验台。实验结果表明:液氦温度为4.17K(饱和压力为96kPa)时,氦液化率为74L/d;液氦温度为4.42K(饱和压力为121kPa)时,液化率为116L/d,经拟合,在4.2K(饱和压力为100kPa)时液化率为83L/d,并且通过100小时以上的连续运行,说明该氦液化装置自循环性能良好。通过实验发现:实测氦液化率远大于制冷机冷头制冷量对应的计算氦液化率。分析认为:G-M制冷机气缸壁对氦气预冷是提高实际氦液化率的主要因素。

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本论文在 166MeV 的束流能量下,利用重离子熔合蒸发反应 142 Nd(32 S, 1p3nγ )170 Re 布居了 170 Re 的高自旋激发态,用 12 套带 BGO反康普顿抑制的高 纯锗探测器阵列进行了在束 X-γ 和γ γ − 符合测量。在 210MeV 的束流能量下, 利用重离子熔合蒸发反应 146 Nd(35 Cl,5nγ )176 Ir 产生具有 β+ / EC 衰变性质的 核素 176 Ir, 由氦喷嘴快速带传输系统将反应产物送到低本底区,用一台小平面探 测器、一台轴对称型高纯锗探测器和一台 CLOVER 探测器进行了γ γ − 符合和 t γ − 单谱测量。基于这些测量结果,研究了 170 Re 的高自旋态和 176 Ir 的 β+ / EC 衰变性质。 本工作基于γ−γ符合关系及周围邻近核已知信息的综合分析,首次建立了包 括 16 个能级 26 条γ 跃迁的双奇核 170 Re 的转动带能级纲图,并利用推转壳模型、 粒子转子模型等对其进行了分析和讨论。根据实验提取出的准粒子顺排、 Routhian、旋称劈裂等结构信息和邻近双奇核带结构系统学知识的比较分析,指 出该带的两准粒子组态是 11/213/2 hi π ν ⊗ ,并且该带在低自旋出现旋称反转。 基于对 176 Ir 核 β+ / EC衰变实验数据的离线处理分析,对早先发表的 176 Ir 衰 变γ 跃迁进行确认的同时又发现了 4 个新能级和 13 条新的γ 射线,丰富了 176 Os 核的低位激发态能级纲图。根据典型γ 射线的衰变时间谱建议了 176 Ir核的一个长 寿命低自旋同核异能态,同时通过两准粒子耦合的半经验计算建议了其组态。

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细齿缺萼苔 (G .crenulatumGott.exCarr.)的中国记录为错误鉴定 ,标本实为中华缺萼苔(G .sinenseK .Muell.) ,应被移出中国苔藓植物区系。研究发现了多号西藏产中华缺萼苔标本 ,将中华缺萼苔其在中国的分布范围从云南的模式产地扩展到了西藏。对中华缺萼苔进行了形态特征描述和分布分析 ,并提供了特征示意图

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Thrombin-binding aptamer is found to bind hemin to form a catalytic complex whose activity is significantly promoted by the addition of thrombin, which enables the colorimetric detection of thrombin with high specificity and sensitivity in a facile way.

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Two new stepladder conjugated polymers, that is, poly(7,7,15,15-tetraoctyldinaphtho[1,2-a:1',2'-g]-s-indacene) (PONSI) and poly(7,7,15,15-tetra(4-octylphenyl)dinaphtho[1,2-a:1',2'-g]-s-indacene) (PANSI) with alkyl and aryl substituents, respectively, have been synthesized and characterized. In comparison with poly(indenofluorene)s, both polymers have extended conjugation at the direction perpendicular to the polymer backbone because of the introduction of naphthalene moieties. The emission color of the polymers in film state is strongly dependent on the substituents. While PONSI emits at a maximum of 463 nm, PANSI with the same backbone but aryl substituents displays dramatically redshifted emission with a maximum at 494 nm.

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This paper presented a new approach for preparing a new type of slow-release membrane-encapsulated urea fertilizer with starch-g-PLLA as biodegradable carrier materials. By solution-casting and washing rapidly with water the urea was individually encapsulated within the starch matrix modified by L-lactide through in situ graft-copolymerization.