分类回归树及其在教师科研工作评估中的应用

为了建立科研评估科学合理的评价指标体系,并能最大程度地反映评价对象的真实水平,对相应评价支术进行了研究.讨论了分类回归树方法,并介绍了它在开发高校科研决策支持系统中的应用.利用分类回归树方法对教师科研工作进行评估,开辟了评估方法的一条新途径.     

无线传感器网络的安全机制

近年来，随着微电子技术和无线通信技术的进步，推动了低功耗、低价格、多功能传感器的快速发展，进而也促进了无线传感器网络的发展．无线传感器网络在军事、医疗、商业等多个领域均有广阔的应用市场．针对无线传感器网络的特点，本文主要阐述它在通信过程中存在的安全威胁、分析它的安全需求和采取的安全机制，确保无线通信的安全．     

Self-assembled silver nanoprisms monolayers at the liquid/liquid interface

A crown ether derivative (4′-aminobenzo-15-crown-5 hydrotetrafluoroborate) can mediate the self-assembly of silver nanoprisms at the liquid/liquid interface in the form of a stable hybrid nanocomposite film. The metallic luster of the interfacial film results from the electronic coupling of Ag nanoprisms, suggesting the formation of closely packed nanoprism thin films. The interfacial film of nanoprisms could be transferred to solid substrates as a Langmuir–Blodgett film. The properties of films were studied by UV–vis spectroscopy and transmission electron microscopy.     

具有未知高频增益的模型参考自适应控制的性能提高

在高频增益kp 未知的假设下, 提出了一种修改的模型参考自适应控制器. 证明了这种修改的模型参考自适应控制方案具有稳定性和鲁棒性 ;同时通过选取的控制律, 其瞬态性能也明显提高.     

矩阵分解的多变量模型参考自适应控制

研究了基于高频增益矩阵分解的多变量模型参考自适应控制 .为此首先基于矩阵分解构造出新的参数化方程 ,选取必然等价自适应控制律 .然后 ,引入规范化信号和类Lyapunov函数 ,获得了规范化自适应律 .并进一步给出了虚拟规范化信号的有用性质 .最后 ,严格地给出了闭环系统的稳定性和收敛性分析     

High temperature scaling of Ni-15Cu-5Al alloy in 1×105 Pa pure oxygen

The oxidation of the ternary alloy Ni-15Cu-5Al in 1×10⁵ Pa pure oxygen at 700 °C and 800 °C was studied. The results show that the behavior of the Ni-rich alloy is similar to that of the binary Ni-Al alloy with the same Al content in the form of an external NiO layer coupled to the internal oxidation of aluminium. The presence of 15% (mole fraction) Cu cannot modify substantially the values of relevant parameters affecting the transition from the internal to the external oxidation of aluminium. The presence of 5% Al reduces the oxidation rate of the corresponding Ni-Cu alloy during the whole oxidation stages, though 5% Al is still insufficient to form protective external alumina scales. Foundation item: Project (50071058; 50271079) supported by the National Natural Science Foundation of China     

Interstitial effects of B addition on the metamagnetic transition and magnetocaloric effect in tetragonal Cu2Sb-type Mn1.95Cu0.05Sb alloys

Mn_1.95Cu_0.05SbB_x (x = 0, 0.06 and 0.1) alloys had been prepared and B interstitial effects on metamagnetic transition were studied. The metamagnetic transition temperature was reduced and thermal hysteresis was widened by higher B concentration. The saturation magnetization and the magnetic entropy change were increased by moderate amount of B addition. However, too high B composition led into the sluggish metamagnetic transition. By relating with crystallographic structure, our results further indicated that the electron density of the atoms at MnⅡ position plays critical role on influencing the metamagnetic transition in tetragonal Cu₂Sb-type Mn_1.95Cu_0.05Sb alloys.     

纳米光催化剂制备及处理印染废水分析

印染行业的快速发展伴随着严重的水污染,为缓解现状就必须采取措施予以妥善处理。而纳米光催化剂无毒无害、经济易得且具有显著的降解能力,适用于印染废水降解。对此,对纳米光催化剂制备及处理印染废水作了分析,以供参考。     

Spin-polarized transport properties of Fe-oligoporphyrin dimer-based molecular device

By applying the density functional theory and the nonequilibrium Green’s function formalism, we investigate the spin-polarized transport properties of a Fe-oligoporphyrin dimer (Fe-P2TA) sandwiched between two armchair single-walled carbon nanotube electrodes. The results show that the system can present high-efficiency magnetoresistance, spin-filtering, and low-bias negative differential resistance effects with the help of magnetic field modulation. The above results are explained by the evolution of the spin-polarized transmission spectra and the molecular projected self-consistent Hamiltonian eigenstates with applied bias. Therefore, the system provides the possibilities for a multifunctional molecular spintronic device design.     

Facile fabrication of a binary NiCo phosphide with hierarchical architecture for efficient hydrogen evolution reactions

Exploring and designing efficient non-noble catalysts formed by element doping and nanostructure modification for the hydrogen evolution reaction (HER) is of critical importance with respect to sustainable resources. Herein, we have prepared a three-dimensional binary NiCo phosphide with hierarchical architecture (HA) composed of NiCoP nanosheets and nanowires grown on carbon cloth (CC) via a facile hydrothermal method followed by oxidation and phosphorization. Due to its unique hierarchical nanostructure, the NiCoP HA/CC electrocatalyst exhibits excellent performance and good working stability for the HER in both acidic and alkaline conditions. The obtained NiCoP HA/CC shows excellent HER activity with a low potential of 74 and 89 mV at 10 mA cm⁻², a small Tafel slope of 77.2 and 99.8 mV dec⁻¹ and long-term stability up to 24 h in acidic and alkaline electrolyte, respectively. NiCoP HA/CC, a non-noble metal material, is a promising electrocatalyst to replace noble metal-based electrocatalysts for the HER.