退火处理对新型无镁Y0.7La0.3Ni3.25Al0.1Mn0.15储氢合金结构和电化学性能的影响

通过电弧熔炼制备了无镁La-Y-Ni系A₂B₇型Y_0.7La_0.3Ni_3.25Al_0.1Mn_0.15合金, 并在高纯0.2 MPa Ar气氛下分别对合金进行850~1050 ℃真空24 h退火热处理. 通过X射线衍射(XRD)、 中子衍射(ND)、 扫描电子显微镜/能量分散谱(SEM/EDS)和电化学测试方法研究了退火温度对合金结构和性能的影响. 结构分析表明, 铸态合金由CaCu₅, Ce₅Co₁₉, Gd₂Co₇, Ce₂Ni₇多相构成, 随着退火温度升高, CaCu₅, Ce₅Co₁₉, Gd₂Co₇相逐步减少直至消失, Ce₂Ni₇主相相丰度逐步增加. 900~950 ℃退火时, 合金为单相Ce₂Ni₇结构. 退火温度继续升高, 合金中出现少量PuNi₃相. 合金电极的最大放电容量随着退火温度的升高先增加后降低. 从铸态的307.6 mA·h/g增加到900 ℃退火时的最大值393.1 mA·h/g, 后又降到1050 ℃退火时的366.4 mA·h/g. 合金电极的电化学循环稳定性随退火温度的升高而升高, 循环100次后电化学容量保持率(S₁₀₀)从铸态的66%上升到1050 ℃退火后的88.5%, 900~950 ℃退火时, 合金电极具有较好的综合电化学性能.     

Progressive refinement for robust image registration

A new image registration algorithm with robust cost function and progressive refinement estimation is developed on the basis of direct method (DM). The robustness lies in M-estimation to avert larger local noise and outliers.     

Effect of polymerically‐modified clay structure on the morphology and properties of UV‐cured polyurethane acrylate/clay nanocomposites

Polyurethane acrylate (PUA)/clay nanocomposites were prepared by UV‐curing from a series of styrene‐based polymerically‐modified clays and PUA resin. Effect of the chemical structure of the polymeric surfactants on the morphology and tensile properties of nanocomposites has been explored. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) experimental results indicated that surfactants having hydroxyl or amino groups show better dispersion and some of the clay platelets were fully exfoliated. However, the composites formed from pristine clay and other polymerically‐modified clays without hydroxyl or amino groups typically contained both tactoids and intercalated structure. The mechanical properties of PUA composites were greatly improved where the organoclays dispersed well. Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) were carried out to examine the thermal properties of the composites. The results showed that the loading of polymerically‐modified clays do not effect the thermal stability, but increased the Tgs of PUA/clay composites. Copyright © 2010 John Wiley & Sons, Ltd.     

基于SOM算法和免疫神经网络的飞机燃油系统故障诊断

针对传统的飞机燃油系统故障诊断方法如硬件冗余方法和系统模型检测方法存在的飞机重量限制和难以建立精确数学模型的问题,设计了一种基于SOM算法和BP神经网络的故障诊断模型;首先,建立了系统故障诊断模型并对诊断原理进行了描述,然后,对故障征兆数据进行预处理,即先采用SOM算法进行连续属性离散化处理,再通过粗糙集互信息方法进行属性降维,以减少数据量和提高诊断效率;最后,建立了基于BP神经网络的故障诊断模型,为了进一步提高故障诊断精度,在采用免疫优化算法对BP神经网络故障诊断模型中的各参数即权值和阈值等进行优化的基础上,进一步采用BP反向传播算法进行参数调整,从而得到最终的故障诊断模型。通过飞机燃油系统故障诊断实例仿真实验证明了文中方法能较为精确地实现故障诊断,且与其它方法相比,具有较高的诊断精度和诊断效率,具有较大的优越性。     

A ruthenium(II) complex with a methylated polypyridine ligand: synthesis,DNA binding,and antiproliferation activity

Transition Metal Chemistry - A ruthenium polypyridine complex, [Ru(mptpy)(Mmptpy)Cl][PF6]2 (Ru1, mptpy?=?4-(4-methylphenyl)-2,2′,6′,2″-mptpyridine,...     

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB12 ceramics from first-principles calculations

Although ZrB₁₂ is a promising advanced material because of the boron cuboctahedron cages, the hardness of ZrB₁₂ remains controversy. Here, we apply first-principles calculations to study the influence of transition metals (4d- and 5d-) on the hardness and thermodynamic properties of ZrB₁₂. The calculated hardness of ZrB₁₂ is 32.9 GPa, which is in good agreement with the previous theoretical result. Importantly, the calculated hardness of Re-doped ZrB₁₂ is up to 40.0 GPa, which is a potential superhard material. The essential reason is that the alloying element of Re enhances the localized hybridization of B B and Zr B atoms, and then forms the strong B B covalent bond and Zr B bond. The result is well demonstrated by the chemical bonding and lattice parameter. Here, our work shows that the alloying elements of Nb, Mo, and Re enhance the thermodynamic properties of ZrB₁₂. The Debye temperature of Re-doped ZrB₁₂ is 1225.2 K, which is larger than that of the parent ZrB₁₂ (1213.5 K).     

干式生化膜片的制备及其应用

建立了一种快速检测血液中二氧化碳结合力(CO₂-CP)、葡萄糖(GLU)、尿酸(UA)含量的干式生化分析方法。筛选出合适的膜材料作为干片载体, 制备干片, 用干式生化分析仪检测干片, 建立了测定血液中CO₂-CP、GLU、UA含量的标准曲线, 对所建立的方法进行加标回收实验、稳定性实验、批间、批内重复性实验、方法学比较。 此法制备的干片颜色梯度明显、显色均匀, 测定CO₂-CP、GLU、UA的线性范围较宽;批间与批内变异系数均小于5%, 重复性良好;与临床湿化学检测相比具有良好的相关性, 相关系数大于0.99, 可应用于临床检测。     

Preparation and electrochemical properties of Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript>/Ti<Subscript>4</Subscript>O<Subscript>7</Subscript> composite for lithium-ion batteries

In order to improve the rate capability of Li₄Ti₅O₁₂, Ti₄O₇ powder was successfully fabricated by improved hydrogen reduction method, then a dual-phase composite Li₄Ti₅O₁₂/Ti₄O₇ has been synthesized as anode material for lithium-ion batteries. It is found that the Li₄Ti₅O₁₂/Ti₄O₇ composite shows higher reversible capacity and better rate capability compared to Li₄Ti₅O₁₂. According to the charge-discharge tests, the Li₄Ti₅O₁₂/Ti₄O₇ composite exhibits excellent rate capability of 172.3 mAh g^?1 at 0.2 C, which is close to the theoretical value of the spinel Li₄Ti₅O₁₂. More impressively, the reversible capacity of Li₄Ti₅O₁₂/Ti₄O₇ composite is 103.1 mAh g^?1 at the current density of 20 C after 100th cycles, and it maintains 84.8% of the initial discharge capacity, whereas that of the bare spinel Li₄Ti₅O₁₂ is only 22.3 mAh g^?1 with a capacity retention of 31.1%. The results indicate that Li₄Ti₅O₁₂/Ti₄O₇ composite could be a promising anode material with relative high capacity and good rate capability for lithium-ion batteries.     

电化学发光生物传感技术在快速检测心肌梗死标志物中的研究进展

设计和发展简便、高灵敏、高选择性的分析手段以检测低浓度急性心肌梗死生物标志物是目前临床诊断迫切的需求。 电化学发光分析法由于具有稳定性好、灵敏度高、线性范围宽及可控性强等优点,能有效地进行低浓度样品检测。 该方法与生物传感技术相结合,有利于实现生物体液等复杂样品中极低含量急性心肌梗死生物标志物的快速检测。 本文综述了电化学发光生物传感技术在快速检测心肌梗死标志物中近5年的进展,介绍了电化学发光探针和共反应物,以及多组分生物传感检测技术等,并对其在心肌梗死标志物分析中的应用进行了总结。     

Giant dielectric permittivity observed in Li and Ti doped NiO

A giant low-frequency dielectric constant ( epsilon 0 approximately 10(5)) near room temperature was observed in Li,Ti co-doped NiO ceramics. Unlike currently best-known high epsilon 0 ferroelectric-related materials, the doped oxide is a nonperovskite, lead-free, and nonferroelectric material. It is suggested that the giant dielectric constant response of the doped NiO could be enhanced by a grain boundary-layer mechanism as found in boundary-layer capacitors. In addition, there is about a one-hundred-fold drop in the dielectric constant at low temperature. This anomaly is attributed to a thermally excited relaxation process rather than a thermally driven phase transition, as for that yielding ferroelectrics.