排序方式: 共有20条查询结果,搜索用时 31 毫秒
1.
钾明矾(KAl(SO4)2·12H2O)有较高的潜热和良好的导热性(熔化热232.4kJ/kg,导热系数为0.55W/m·K),熔点为91℃,是中低温相变材料中较有开发价值的一种.但是它的过冷度高达19.8℃,并且由于相变过程伴随着结晶水的蒸发使无机盐的使用寿命大大降低.本文通过冷指法及添加成核剂的方法对硫酸铝钾的过冷现象进行了研究,结果表明成核剂NiSO4·6H2O、MgCl2·6H2O能较好的改善过冷现象,当MgCl2·6H2O的添加量为2;时可使过冷度降为零,且能保持钾明矾的相变温度而不使其降低.利用MgCl2·6H2O具有很强的吸湿性,可以补充相变过程中损失的水分,使相变材料的使用寿命大大提高. 相似文献
2.
Shumin Li 《偏微分方程(英文版)》2002,15(1):46-68
In this paper, we consider Cauchy problem for general first order inho- mogeneous quasilinear strictly hyperbolic systems. Under the matching condition, we first give an estimate on inhomogeneous terms. By this estimate, we obtain the asymptotic behaviour for the life-span of C¹ solutions with “slowly” decaying and small initial data and prove that the formation of singularity is due to the envelope of characteristics of the same family. 相似文献
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4.
李明融 《数学物理学报(B辑英文版)》2007,27(4):703-734
In this article the author works with the ordinary differential equation u" = |u|^p for some p 〉 0 and obtains some interesting phenomena concerning blow-up, blow-up rate, life-span, stability, instability, zeros and critical points of solutions to this equation. 相似文献
5.
Dexing Kong 《偏微分方程(英文版)》1996,9(3):221-236
In this paper, we give a lower bound for the life-span of classical solutions to the Cauchy problem for first order nonlinear hyperbolic systems with small initial data, which is sharp, and give its application to the system of one-dimensional gas dynamics; for the Cauchy problem of the system of one-dimensional gas dynamics with a kind of small oscillatory initial data, we obtain a precise estimate for the life-span of classical solutions. 相似文献
6.
本文利用特征线的方法,得到关于拟线性双曲方程组Cauchy问题经典解的一致先验估计.这样的估计给出了系统经典解存在区间的下界. 相似文献
7.
李明融 《数学物理学报(B辑英文版)》2007,(4)
In this article the author works with the ordinary differential equation u″= |u|~p for some p>0 and obtains some interesting phenomena concerning blow-up,blow-up rate,life-span,stability,instability,zeros and critical points of solutions to this equation. 相似文献
8.
Formation of Singularities for Quasilinear Hyperbolic Systems with Characteristics with Constant Multiplicity 下载免费PDF全文
Libin Wang 《偏微分方程(英文版)》2003,16(3):240-254
In this paper we consider the Cauchy problem for quasilinear hyperbolic systems with characteristics with constant multiplicity. Without restriction on characteristics with constant multiplicity(> 1), under the assumptions that there is a genuinely nonlinear simple characteristic and the initial data possess certain decaying properties, the blow-up result is obtained for the C¹ solution to the Cauchy problem. 相似文献
9.
In this article, we investigate the lower bound of life-span of classical solutions of the hyperbolic geometry flow equations in several space dimensions with “small” initial data. We first present some estimates on solutions of linear wave equations in several space variables. Then, we derive a lower bound of the life-span of the classical solutions to the equations with “small” initial data. 相似文献
10.
Yang Zhifeng 《Central European Journal of Mathematics》2008,6(4):568-575
The initial boundary value problem for a viscoelastic equation with nonlinear damping in a bounded domain is considered. By
modifying the method, which is put forward by Li, Tasi and Vitillaro, we sententiously proved that, under certain conditions,
any solution blows up in finite time. The estimates of the life-span of solutions are also given. We generalize some earlier
results concerning this equation.
相似文献