低功率低损耗网络路由(Routing Protocol for low power and Lossy network,RPL)是无线物联网的典型路由。由于未采用集中安全机制,RPL路由易受女巫攻击。为此,提出基于接收信号强度的防御女巫攻击的RPL路由(RSSI-based against Sybil a...低功率低损耗网络路由(Routing Protocol for low power and Lossy network,RPL)是无线物联网的典型路由。由于未采用集中安全机制,RPL路由易受女巫攻击。为此,提出基于接收信号强度的防御女巫攻击的RPL路由(RSSI-based against Sybil attack RPL,RSPL)。RSPL路由通过统计接收信号的强度值,并结合邻居节点的观察,估算节点可信度,进而检测攻击节点。同时,利用链路的传输期望次数和链路信任值修改RPL路由中的目标函数,进而阻止攻击节点参与路由。性能分析表明,相比同类算法,提出的RSPL路由降低了检测攻击节点的误检率,提高了数据包传递率。展开更多
Conventional two-layered thermal barrier coatings （TBCs） are prepared by electron beam physical vapor deposition （EB-PVD） with ZrO2-8 wt% Y2O3 （8YSZ） as top coat and CoCrAlY as bond coat on disk-shaped Ni based ...Conventional two-layered thermal barrier coatings （TBCs） are prepared by electron beam physical vapor deposition （EB-PVD） with ZrO2-8 wt% Y2O3 （8YSZ） as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its surface roughness and the surface micro-hardness. A thermal cycling test at 1 273 Kx55 rain and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the parabolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide （TGO） responsible mainly for the failure of TBCs.展开更多
基于Backes Andre Ricardo等人提出的“构造伴生动态演化网络”、生成“高维解释向量”的纹理图片分类法,研究了Kylberg纹理图像库的分类问题。通过将数据集图片样本进行二次分割以减少该算法预处理计算量、提出了构建纹理网络时的“网...基于Backes Andre Ricardo等人提出的“构造伴生动态演化网络”、生成“高维解释向量”的纹理图片分类法,研究了Kylberg纹理图像库的分类问题。通过将数据集图片样本进行二次分割以减少该算法预处理计算量、提出了构建纹理网络时的“网络顶点随机化、抽样采集”策略,该思路可进一步减少算法的时间开销。该类纹理图片数据高维几何数字特征的提取流程易于实现,扩展了原算法的适用范围。数值结果表明算法对旋转操作、噪声干扰具有一定的鲁棒性,具备一定潜在应用前景。展开更多
The polycrystalline Ni_(48.2)Mn_(22.4) Ga_(29.4) alloys were prepared by means of melting in argon arc furnace.X-ray diffraction pattern indicates a fcc cubic structure with a lattice parameter of 0.5822nm at room tem...The polycrystalline Ni_(48.2)Mn_(22.4) Ga_(29.4) alloys were prepared by means of melting in argon arc furnace.X-ray diffraction pattern indicates a fcc cubic structure with a lattice parameter of 0.5822nm at room temperature.The phase transformation temperatures were:1℃for martensite start temperature,-11℃for martensite finish temperature,3℃for austenite start temperature and 11℃for austenite start temperature,respectively.The results showed that the effect of magnetic field on the strains increases with the decrease of temperature.A strain of 2.1×10^(-4)was obtained with an applied magnetic field of 5 kOe at-66℃.展开更多
文摘低功率低损耗网络路由(Routing Protocol for low power and Lossy network,RPL)是无线物联网的典型路由。由于未采用集中安全机制,RPL路由易受女巫攻击。为此,提出基于接收信号强度的防御女巫攻击的RPL路由(RSSI-based against Sybil attack RPL,RSPL)。RSPL路由通过统计接收信号的强度值,并结合邻居节点的观察,估算节点可信度,进而检测攻击节点。同时,利用链路的传输期望次数和链路信任值修改RPL路由中的目标函数,进而阻止攻击节点参与路由。性能分析表明,相比同类算法,提出的RSPL路由降低了检测攻击节点的误检率,提高了数据包传递率。
基金National Natural Science Foundation of China (50571005 50420130032)
文摘Conventional two-layered thermal barrier coatings （TBCs） are prepared by electron beam physical vapor deposition （EB-PVD） with ZrO2-8 wt% Y2O3 （8YSZ） as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its surface roughness and the surface micro-hardness. A thermal cycling test at 1 273 Kx55 rain and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the parabolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide （TGO） responsible mainly for the failure of TBCs.
文摘基于Backes Andre Ricardo等人提出的“构造伴生动态演化网络”、生成“高维解释向量”的纹理图片分类法,研究了Kylberg纹理图像库的分类问题。通过将数据集图片样本进行二次分割以减少该算法预处理计算量、提出了构建纹理网络时的“网络顶点随机化、抽样采集”策略,该思路可进一步减少算法的时间开销。该类纹理图片数据高维几何数字特征的提取流程易于实现,扩展了原算法的适用范围。数值结果表明算法对旋转操作、噪声干扰具有一定的鲁棒性,具备一定潜在应用前景。
基金Supported by the National Natural Science Foundation of China under Grant No.59731030.
文摘The polycrystalline Ni_(48.2)Mn_(22.4) Ga_(29.4) alloys were prepared by means of melting in argon arc furnace.X-ray diffraction pattern indicates a fcc cubic structure with a lattice parameter of 0.5822nm at room temperature.The phase transformation temperatures were:1℃for martensite start temperature,-11℃for martensite finish temperature,3℃for austenite start temperature and 11℃for austenite start temperature,respectively.The results showed that the effect of magnetic field on the strains increases with the decrease of temperature.A strain of 2.1×10^(-4)was obtained with an applied magnetic field of 5 kOe at-66℃.
