For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation inde...For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation independent of the vector field is constructed explicitly, which can reduce not only dimesion of the vector field by one, but also make the reduced vector field preserve the corresponding ( n - 1)-form. In partic ular, while n = 3, an important result can be directly got which is given by Me,ie and Wiggins in 1994.展开更多
目的构建m asp in/pEFIRES-N表达载体,为深入研究m asp in基因抑制肝癌生长、转移、浸润作用和机制奠定基础。方法PCR扩增m asp in基因全长,将表达载体pEFIRES-N用EcoRⅠ+XbaⅠ进行双酶切后,T4DNA连接酶连接成重组质粒,稳定转染到肝癌...目的构建m asp in/pEFIRES-N表达载体,为深入研究m asp in基因抑制肝癌生长、转移、浸润作用和机制奠定基础。方法PCR扩增m asp in基因全长,将表达载体pEFIRES-N用EcoRⅠ+XbaⅠ进行双酶切后,T4DNA连接酶连接成重组质粒,稳定转染到肝癌高转移细胞株mHCC-97中进行表达,检测稳定转染前后m asp in表达的变化。结果重组质粒在大肠杆菌株JM109内扩增。提纯、纯化后用EcoRⅠ、XbaⅠ酶切鉴定及测序鉴定证明m asp in基因已完整、正确的插入到pEFIRES-N表达载体,并在肝癌MHCC-97细胞中上调了m asp in基因mRNA和蛋白水平表达,抑制了肝癌MHCC-97细胞增殖及浸润。结论成功构建了m asp in/pEFIRES-N表达载体,能在真核细胞中表达。展开更多
随着信息技术的不断发展,各种SQL注入攻击工具层出不穷,攻击类型多变万化,SQL注入问题一直是网络安全的主要问题。因此,针对SQL注入攻击提出一种基于N-Gram和TFIDF(term frequency inverse document frequency)的入侵检测方法。其核心...随着信息技术的不断发展,各种SQL注入攻击工具层出不穷,攻击类型多变万化,SQL注入问题一直是网络安全的主要问题。因此,针对SQL注入攻击提出一种基于N-Gram和TFIDF(term frequency inverse document frequency)的入侵检测方法。其核心思想是:首先在预处理阶段使用N-Gram技术选取特征词,再利用TFIDF技术进行SQL语句文本向量化处理,然后在此数据集基础上训练SVM分类器,最后通过与现有研究进行对比来检测分类效果。实验结果表明,与直接使用预先定义好的特征向量相比,此方法在保证召回率的基础上,准确率有所提高。展开更多
文摘For a n-dimensional vector fields preserving some n-form, the following conclusion is reached by the method of Lie group. That is, if it admits an one-parameter, n-form preserving symmetry group, a transformation independent of the vector field is constructed explicitly, which can reduce not only dimesion of the vector field by one, but also make the reduced vector field preserve the corresponding ( n - 1)-form. In partic ular, while n = 3, an important result can be directly got which is given by Me,ie and Wiggins in 1994.
文摘目的构建m asp in/pEFIRES-N表达载体,为深入研究m asp in基因抑制肝癌生长、转移、浸润作用和机制奠定基础。方法PCR扩增m asp in基因全长,将表达载体pEFIRES-N用EcoRⅠ+XbaⅠ进行双酶切后,T4DNA连接酶连接成重组质粒,稳定转染到肝癌高转移细胞株mHCC-97中进行表达,检测稳定转染前后m asp in表达的变化。结果重组质粒在大肠杆菌株JM109内扩增。提纯、纯化后用EcoRⅠ、XbaⅠ酶切鉴定及测序鉴定证明m asp in基因已完整、正确的插入到pEFIRES-N表达载体,并在肝癌MHCC-97细胞中上调了m asp in基因mRNA和蛋白水平表达,抑制了肝癌MHCC-97细胞增殖及浸润。结论成功构建了m asp in/pEFIRES-N表达载体,能在真核细胞中表达。
文摘随着信息技术的不断发展,各种SQL注入攻击工具层出不穷,攻击类型多变万化,SQL注入问题一直是网络安全的主要问题。因此,针对SQL注入攻击提出一种基于N-Gram和TFIDF(term frequency inverse document frequency)的入侵检测方法。其核心思想是:首先在预处理阶段使用N-Gram技术选取特征词,再利用TFIDF技术进行SQL语句文本向量化处理,然后在此数据集基础上训练SVM分类器,最后通过与现有研究进行对比来检测分类效果。实验结果表明,与直接使用预先定义好的特征向量相比,此方法在保证召回率的基础上,准确率有所提高。
