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基于改进的极端相对论量子分子动力学(UrQMD) 输运模型,通过细致考察初始化、状态方程及两体碰撞等系统研究了INDRA 能区重离子碰撞后出射的自由核子及轻粒子的集体流和核阻止本领等观测量。研究发现,一个采用带动量依赖的软的状态方程及动量修正的密度依赖的核子核子弹性散射截面的动力学输运过程能够很好描述INDRA 全能域内实验获得的中心快度区的氢同位素的直接流。利用该套输运系统还研究了直接流平衡能对对称势能密度依赖强度因子的敏感性。发现,出射的自由中子平衡能敏感依赖于对称势能的密度依赖,而自由质子却不会。同时还发现,利用两Sn 同位素系列反应出射的自由中子直接流的平衡能与初始中子/质子比的关系可以很好地探测对称能的密度依赖。The terms of initialization, equation of state (EoS), and two-body collision in the updated ultrarelativistic quantum molecular dynamics (UrQMD) model are examined in details so as to systematically study the collective flows and the nuclear stopping of free nucleons and light clusters from heavy-ion collisions at INDRA energies. It is seen that at INDRA energies the dynamic transport with a soft EoS with momentum dependence and with the momentum-modified density-dependent nucleon-nucleon elastic cross sections describes the directed flow exhibited by hydrogen isotopes (Z= 1) emitted at midrapidity fairly well. The sensitivity of the balance energy (Ebal) of the directed flow to the strength parameter of the density dependence of symmetry potential energy is further studied with the same parameter set. It is found that the Ebal of neutrons from HICs is particularly sensitive to the density dependence of the symmetry potential energy, while that of protons is not. And, the initial neutron/proton ratio dependence of the balance energy of neutrons from Sn isotopes can be taken as a useful probe to constrain the stiffness of the nuclear symmetry energy. 相似文献
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In this paper, we first give two equalities in the operation of determinant. Using the expression of group inverse with full-rank factorization Ag = F(GF)^-2G and the Cramer rule of the nonsingular linear system Ax = b, we present a new method to prove the representation of group inverse with arlene combination
Ag=∑(I,J)∈N(A) 1/υ^2det(A)IJ ajd AJI.
A numerical example is given to demonstrate that the formula is efficient. 相似文献
Ag=∑(I,J)∈N(A) 1/υ^2det(A)IJ ajd AJI.
A numerical example is given to demonstrate that the formula is efficient. 相似文献
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本文研究了群逆的存在条件及群逆、Drazin逆的表示与计算.利用行列式表示方法,得到了群逆存在的充要条件,给出了群逆的与原矩阵最大非奇异子阵有关的表达式.并推广到Drazin逆.为群逆和Drazin逆的计算提供了一类新的算法. 相似文献
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利用传输矩阵方法计算了铀同位素链$\alpha$ 衰变的穿透几率,并且与常用于计算势垒穿透几率的Wenzel Kramers Brillouin(WKB)近似方法进行了比较,发现由WKB近似方法得到的穿透几率比精确值小40%左右,而且WKB方法带来的误差与$\alpha$ 衰变的衰变能有很好的抛物线关系。基于结团模型,利用传输矩阵方法得到$\alpha$ 粒子穿透势垒的精确几率,计算了铀同位素链$\alpha$ 衰变的半衰期。还研究了势阱深度$V_0$ 、弥散宽度$a$ 和主量子数$G$ 对半衰期的影响。结果表明,考虑一组同位旋依赖的势阱深度和弥散宽度参数,结团模型能够较好地再现铀同位素链$\alpha$ 衰变的半衰期。 相似文献
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基于产线工艺制备了纳米绒面多晶硅太阳电池,并表征其光电转换性能。研究结果表明:相对传统微米绒坑,纳米绒面能够提升多晶硅太阳电池的短路电流,相应的光电转换效率绝对值提升大于0.4%,产线均值光电转换效率超过了19.1%。结合漫反射光谱和外量子效率测试结果,改进的光电转换的原因归结为纳米绒面能够有效地诱捕短波和长波太阳光子,增强短波和长波太阳光响应。本研究证实纳米绒面多晶硅太阳电池可利用产线工艺制备且具有较高的光电转换效率,能够实现产业化。 相似文献
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长方体水柜边界由一个或两个竖直的平面组成,实验发现边界处的漂浮气泡球心落在边界上。假设气泡自由能主要由表面张力势能组成,数值计算和小量分析验证了气泡气体体积不变下,气泡表面积极小时,气泡球心落在边界上。 相似文献