994 resultados para 197-1205A


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许多提取核反应过程中熵产生的方法只适用于高能核反应过程 ,而约化d的产额方法可以用于较低能量的重离子核反应中 .对于 3 5MeV/u40 Ar+ 197Au的核反应过程 ,利用这种方法所得的熵和约化带电粒子多重性提取的熵结果一致 .对于后角热核发射体系 ,实验提取的核温度为 ( 4.7± 1 .2 )MeV ,熵为S/A =2 .5± 0 .5,根据实验提取的熵和核温度可以确定其碎裂密度小于 0 .1 ρ0

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根据量子统计模型 (QSM )的计算分析 ,找到了一个提取核反应过程中熵产生的新的可观测量 .核反应过程中约化d的产额d/ (d +t+3 He+4 He)和熵有单调的函数关系 ,并且和体系的碎裂密度 (ρ/ ρ0 )及体系的N/Z都无关 ,可以作为提取核反应过程中熵产生的一个观测量 .和目前已经有的其他方法相比 ,约化d产额这一提取熵方法可以用于较低能量的重离子核反应中 ,并且数据处理分析简单 .对于 35MeV/u4 0 Ar +197Au的核反应过程所提取的熵和利用约化带电粒子多重性提取的熵结果一致 .结合后角类靶热核发射体系实验提取的同位素核温度为 4 7±1 2MeV及S/A =2 5± 0 5 ,根据熵和核温度的关联关系 ,可以确定其Breakup密度接近但小于 0 1(ρ/ ρ0 )

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利用硅半导体+CsI(T1)闪烁体望远镜测量35MeV/u40Ar+197Au中发射的轻带电粒子,用能谱斜率方法和双同位素产额比方法提取了核温度参量.研究了热核发射过程中的统计发射规律.

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用能量密度公式及小液滴模型给出的费米密度分布,并引入中子皮及中子分布弥散度随中子过剩自由度增加而增加这一因素,计算了重离子反应在相互作用势及熔合位垒。熔合位垒的计算值和实验值符合很好,特别是在中重核区域,改善了以前的计算结果。详细研究了亲近势标度,发现用中子皮及中子分布弥散度的变化能较好地解释中子过剩自由度对新近势标度偏离的影响。本工作对奇异核结构与核反应性质的研究无疑是有用的。我们利用HIRFL提供的46.7MeV/u ~(12)C束轰击~(58)Ni、~(115)In、~(197)Au研究了反应中发射的α粒子角分布和能谱。从速度表象中洛仑兹不变截面等高图中明显看到发射α粒子的三个源。用这三个源的运动模型成功拟合了α粒子能谱,所提取的参数符合费米气体模型计算结果,并讨论了能谱及拟合参数对靶的依赖关系。认为快速源实质上来自弹核碎裂或类弹核碎裂

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本论文的工作:利用两体裂变角关联技术,辅之以飞行时间测量,测定了47MeV/u的~(12)C轰击~(197)Au和~(209)Bi靶中心碰撞对应的线性动量转移(LMT),得到了关联裂片出射的共面歧离分布,同时还发现了关联角很小且共面歧离很大的裂变事件,并得到了其相对速度分布。从测到的LMT分布中,得到中心碰撞对应的最可几线性动量转移约占入射动量的65%,相应于单核子线性动量转移约为192MeV/c.A,进而还估算出了所形成热核的激发能上限。在对关联裂片出射的共面歧离效应研究中,发现了共面歧离宽度是热核激发能的较好量度之一。并给出了共面歧离宽度跟热核单核子激发能的经验关系;还用简化的裂片级联蒸发模型估算了蒸发中子、质子和α粒子的平均多重性

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通过对中能区Ar+Au/Tb/Ag反应中高激发核的发射时标、发射次序、发射机制、核温度、集体运动等衰变特性的研究,提取了轻粒子和中等质量碎片(IMF)的发射时间,IMF发射时间随束流能的升高而变短,发射机制逐渐由相继衰变过渡至多重碎裂。研究了轻粒子和碎片间的发射次序,对高能粒子和碎片,轻粒子先于碎片发射,而低能时,则为碎片先于轻粒子发射。IMF发射成分与角度和碰撞参数有关,前角区来自于弹核碎裂,后角区来自于类靶热核的蒸发。在平面和出平面研究表明,中速粒子和碎片为在平面发射占主导,即存在类转动效应;对轻粒子,转动效应随粒子质量增加而增加;对中速产物均观测到该效应随碰撞参数饿增大而增大。采用几种不同的方法提取了热核的核温度,研究了不同方法之间的区别。

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14 fotografías a color y en tono de grises.

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Servicios registrales

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On 2 June 2005, the Australian Government announced a proposal to amend s. 197 of the Corporations Act. This is to overturn the decision in Hanel v. O'Neill ("Hanel") where the South Australian Supreme Court has expanded the circumstances in which directors of trustee companies can be held personally liable for the debts under the current section 197(1) of the Corporations Act 2001 (Cth). The multiple interpretations presented in Hanel highlighted the uncertainty of s. 197 and this uncertainty is heightened in at least two subsequent cases. The article provides a detailed analysis of how the decision in Hanel is affecting the directors' freedom of management and suggests some precautionary measures that the directors could take as protection against creditor's actions under s. 197. The author welcomes the proposed amendment because the new section will create certainty for directors as to. the scope of their potential personal liability, but contends that the substance of the proposed s. 197 is not acceptable as there is potential for abuse by directors of certain trustee companies.

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The majority decided in Hanel v O’Neill that directors of trustee companies
could be held personally liable to discharge the debts incurred by a
company pursuant to s 197(1) of the Corporations Act 2001 (Cth). On
18 November 2005, legislation was passed to amend s 197(1); this was to
overturn the decision. This article evaluates other relevant cases and
argues that the recent amendment to s 197 is unsatisfactory as it leaves
potential for abuse by directors of certain trustee companies. The article
suggests further reform to the section and to this end, suggests ways for
s 197 to reconcile with other parts of corporate law, such as insolvent
trading and directors’ duties.