Dynamic behavior of the He Ⅱ -He I phase transition under gravity

The phase transition of superfluid helium (He Ⅱ ) to normal fluid helium (He I ) is studied in this note. The He Ⅱ-He I interface is found to move upwards under finite heat current. The temperature tracks are measured by four high resolution temperature sensors (HRTs). And the shifting of the λ point temperature (phase transition temperature)along the cell is studied experimentally and theoretically.Under gravity, the shifting of the λ point temperature increases with the pressure. The experimental results agree well with the theoretical ones.``     

Characterization of Type p Banach Spaces by the Weak Law of Large Numbers

For weighted sums of the form ∑j＝1anjXnj where {anj, 1≤j≤kn ↑∞,n≥1 } is a real constantarray and {Xnj, 1≤j≤kn ,n≥1 } is a rowwise independent, zero mean, random element array in a real sep-arable Banach space of type p, we establish Lr convergence theorem and.a general weak law of large num-bers respectively, conversely, we characterize Banach spaces of type p in terms of convergence in r-thmean and probability for such weighted sums.     

0行列式的定义

补充定义 0阶行列式的值 ,从而完善行列式的有关理论并简化行列式的计算与证明     

Abnormal overpressure distribution and natural gas accumulation in foreland basins,Western China

Shizitan in Jixian County, Shanxi Province, is a site of transitional period from Paleolithic to Neolithic. The dating and the sporopollen analysis show that the middle reaches of the Yellow River where the site is located had been maintaining a steppe environment during 35.1-9.4 kaBP, in which, 35.1-17 kaBP belonged to the last glacial. With cold and dry climate, this period featured a desert steppe environment. In the late of this period, the area had a cold and half-humid steppe environment. The 17.0-11.9 kaBP belonged to the early- and mid-period of the last deglaciation. Mild and half-arid steppe alternates with mild and half-arid steppe, with a small amount of deciduous broadleaf species. During the period of 11.9-10.5 kaBP, cold and dry glacial climate appeared once more, featuring a desert steppe environment. During 10.5-9.4 kaBP, it is mild and half-arid, and later transited toward warm and half-humid. The early phase of this period featured a steppe environment and the later transited into a steppe environment with fairly more deciduous broadleaf species. Microlith, a mark of a transitional period from Paleolithic to Neolithic, was distributed mainly in 17.0-11.9 kaBP. The relatively warm, half-arid and fluctuating steppe environment in the early and medium period of the last deglaciation made a contribution to the appearance and development of Microlithic culture.     

局部环上的矩阵表为初等阵之积的因子个数

讨论了局部环上的矩阵表为初等阵之积的因子个数问题,并推广了域上的相应结论。     

k-一致超图的Laplacian谱的界

讨论了k-一致超图的Laplacian谱的问题，分别得到了k-一致超图的Laplacian谱的上界和下界，并由此推得k-一致超图的Laplacian矩阵是正定矩阵。     

关于Rn上函数f(x)的极值存在定理

在gj(x)=0和gj(x)≥0　(j=1,2,…,m)的约束条件下分别给出了定义在Rn上的函数f(x)极大值存在的若干定理。     

关于S-W BPRE灭绝概率积分表示的构作举例

利用分式线性概率母函数的特性 ,借助对偶过程及其函数变换 ,在作了一些适当的特殊假设的情况下 ,探讨了随机环境分枝过程 BPRE的灭绝概率的具体表示形式 ;并通过两个举例 ,构作了两类独立同分布随机环境分枝过程灭绝概率的积分表示。从而在特殊情况下 ,可通过简单的积分计算求得随机环境分枝过程的灭绝概率。     

一种多级安全系统模型的隐通道流量分析

利用Markov状态机形式化地描述了一种多级的，基于模式转换的安全系统模型，该模型利用系统可分分性构筑，将一个多级的安全系统划分成多个运行模式，利用该模式可提高所设计系统的灵活性，但该模型存在隐通道问题，利用香农信息论和广义图灵测试模型证明该模型中隐通道流量存在上限并给出定量分析，从而为达到可控的系统安全性和灵活性平衡提供了理论基础，采用该系统模型和隐通道流量分析，通过限制模式转换频率和限制参与转换的资源数目等方法可控制隐通道隐患。     

丙纶非织造布基质人工草坪的开发研究

对非织布基质草坪化的可行性进行技术分析，首次提出丙纶非织造布基质草坪化的整套制造方案并进行一系列的实验，数据显示，非织造布的强力可完全胜任草坪基质的需要，在外加保水剂的情况下，非织造布成功模拟了土壤环境，草坪能顺利移植。对非织造布草坪基质进行的经济成本分析可知此产品在市场推广中具有可行性。