986 resultados para Ch`oe, Che-u, 1824-1864


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Imprint date from preface: Sungjŏn kiwŏnhu sa Kyŏnin, sŏ.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

本论文共由两部分组成。第一部分描述了多丝正比室的研制过程。第二部分研究了中能区25MeV/u ~(40)Ar + ~(93)Nb反应中轻粒子发射时间的测量。本论文所研制的多丝正比室灵敏面积为5cm * 5cm。阳极丝由10μm的镀金钨丝组成,丝与丝之间的间距为0.5mm。工作气体为正庚烷,采用感应信号重心读出方法。调试了工作气压在25Torr左右、工作电压~1400v条件下多丝室的工作状态,结果表明该工作条件下,多丝正比室并未工作于正比状态下,须适当增加工作电压和工作气压才能得到较好的位置分辨。并且提出进一步的改进建议。第二部分利用小相对角度内的两粒子关联测量,研究了中能区25MeV/u ~(40)Ar + ~(93)Nb反应中高激发核衰变产生的轻粒子的发射时标。轻粒子发射时间随能量的变化很大,从低能粒子的约500fm/c变化至高能粒子的50fm/c,表明高能粒子来自于热核的早期发射,包含有前平衡发射的粒子,而低能粒子来自于平衡热核的发射。随着入射能的升高和激发能的增加,热核的寿命及其发射时标变短。轻粒子时空演化表明,发射源的核物质密度对轻粒子关联函数的影响较大,尤其是对于发射时间较(τ ≤ 100fm/c)的高能粒子的关联函数,这一影响随着粒子能量降低而减弱。在发射时间较长(τ ≤ 200fm/c)时,这种影响几乎消失。另外随着实验室系角度的增加,平衡发射成分增加,相应地提取的轻粒子的发射时间变长。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

针对①中能反应中同位旋自由度是否达到平衡,②同位旋自由度对几中不同方法测量的核温度是否有影响 这两个基本问题,设计了用30和35MeV/u ~(36,40)Ar轰击~(112,124)Sn反应的实验方案。得到如下结果:对于前角5°处的耗散弹核碎裂产物,丰中子同位素与稳定核的产额比随产物出射动能的增加而减小,而丰质子子同位素与稳定核的产额比随动能的增加而增加,呈现明显的剪刀差分布特性。随耗散时间的增大,产物的平均中质比逐渐由弹核的平均中质比向系统的平均中质比过渡。这个结果说明在该反应中,同位旋自由度没有达到完全平衡。而对于20°处的DIC产物,上述剪刀差分布特性变得更不明显,这是同位旋自由度由非平衡向平衡过渡的表现。后角轻粒子的能谱分析表明,初始热核的同位旋会影响斜率核温度的提取,由于丰中子轻粒子~6He在~(40)Ar + ~(112)Sn系统中的蒸发被抑制,相比~(40)Ar + ~(112)Sn而言,其蒸发比较容易发生在衰变链早期,因此提取的温度偏高,同样,丰质子轻粒子~3He的温度在~(40)Ar + ~(112)Sn中略高。但中后角的同位素产额分析表明,反应系统的同位旋对双同位素比核温度几乎没有影响。核温度作为热核的热力学量,是独立于测量方法的,这种不同的方法得出的差异主要来源于同位旋对衰变机制的影响。作为一个尝试,将中高能反应中的熵的提取推广到这个能区,发现两个系统的熵几乎一致。在量子统计模型框架下,考察核温度与熵的关系发现,~(40)Ar + ~(112)Sn反应的挤出时刻密度略高于~(40)Ar + ~(112)Sn。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mode of access: Internet.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

One of the key problems in conducting surveys is convincing people to participate.¦However, it is often difficult or impossible to determine why people refuse. Panel surveys¦provide information from previous waves that can offer valuable clues as to why people¦refuse to participate. If we are able to anticipate the reasons for refusal, then we¦may be able to take appropriate measures to encourage potential respondents to participate¦in the survey. For example, special training could be provided for interviewers¦on how to convince potential participants to participate.¦This study examines different influences, as determined from the previous wave,¦on refusal reasons that were given by the respondents in the subsequent wave of the¦telephone Swiss Household Panel. These influences include socio-demography, social¦inclusion, answer quality, and interviewer assessment of question understanding and¦of future participation. Generally, coefficients are similar across reasons, and¦between-respondents effects rather than within-respondents effects are significant.¦While 'No interest' reasons are easier to predict, the other reasons are more situational. Survey-specific issues are able to distinguish¦different reasons to some extent.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Se analiza la informaci??n con la que los rankings globales ( Arwu, THE y QS, SCIMAGO; CWTS, HEEACT y CHE; U-Multirank y U-Ranking.) elaboran sus indicadores as?? como las puntuaciones y posiciones resultantes obtenidas por las universidades espa??olas. A partir de una solicitud de participaci??n canalizada desde el Ministerio de Educaci??n, Cultura y Deporte a las 72 universidades espa??olas, p??blicas y privadas que presentan datos de investigaci??n en el Observatorio IUNE, se obtienen y analizan los cuestionarios e informes de datos para la participaci??n en los rankings de 2013 de 19 universidades. A continuaci??n, se describen los datos solicitados a las universidades por los tres rankings, que est??n referidos a profesorado, estudiantes, t??tulos y datos econ??micos. Por ??ltimo, se detallan los datos que cada universidad participante en el estudio aporta a los rankings y con los que ??stos obtienen sus indicadores, mostr??ndose los perfiles de cada una de ellas. Tambi??n se muestra el nivel de concordancia entre los datos solicitados y los aportados.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Editors: O.I. Senkovskii , 1934-1857; A.V. Druzhinin, 1858-1860; A.F. Pisemskii , 1861-1862; P.D. Boborykin, 1863-1865.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mode of access: Internet.