Structural characteristics of oxide nanosphere supported metal nanoparticles

Structural characterization by transmission electron microscopy of metal nanoparticle coatings on oxide nanospheres has been employed to point out the potential of such materials for use as porous support model catalysts. On silica and titania nanospheres of various origins surface-mediated metal deposition at mild temperature conditions has been utilized to fabricate Pt, Pd, Ag, and Au nanoparticle coatings on the oxide supports. Promising coating characteristics have been achieved for Ag and Au nanoparticles by direct reduction on terminating hydroxyl-rich St?ber silica. A high-resolution electron microscopy analysis directed to surface stress, lattice contraction and planar lattice defects of the latter particles revealed no strong metal-support interaction.     

宽带功率放大器PGSC建模方法及预失真研究

针对宽带功率放大器的强记忆效应特性,提出一种功放建模和数字预失真方法——PGSC模型。利用广义记忆多项式(GMP)、特定交叉项(SCT)及记忆时刻信号交叉项(CIMT)3个基函数来构造功放行为模型及数字预失真器,并搭建实际测试平台对模型的精度及线性化效果进行验证。测试结果表明,与PMEC方法相比,PGSC方法建模时的归一化均方误差减少了2.1 dB,数字预失真时输出信号的三阶邻信道功率比降低了4.94/2.03 dB;与GMP方法相比,PGSC方法仅利用73%的系数即可得到更高的模型精度和更好的线性化效果。     

Oxidative coupling of methane over LaCoO3−δ-based mixed oxides

The catalytic activity of LaCoO_3–-based mixed oxides for the oxidative coupling of methane has been tested by TPR and cyclic reaction. Characterization has been done by XRD, TGA and Mössbauer spectrometry. It is likely that the perovskite-crystal structure containing hypervalent metal ions has an important role and that unique structural oxygen species in the perovskite contribute to the partial oxidation of methane.     

锚索格构梁受力分布的现场模型试验研究

通过开展锚索格构与碎石土滑坡相互作用的现场模型试验,研究了格构梁在滑坡推力作用下的受力分布规律。得到以下结论:在锚索约束力的作用下,格构梁的横梁、竖梁受力特征基本相似,节点处受力最大,靠近梁中部受力逐渐减小;在滑坡推力作用下,格构横梁最上排的变形最剧烈,受力最大,中间的一排次之,最下排受力最小,格构横梁从上往下的荷载分担比为70%~85%;在同一滑坡推力作用下,格构横梁和竖梁弯矩分布特征基本相同,节点处正弯矩最大,格构梁中部负弯矩最大,最大正弯矩是最大负弯矩的1.6~2.0倍。另外,还讨论了试验中土压力测试值误差较大的原因。     

基于物元分析法的水资源管理现代化评价

为科学合理地评价区域水资源管理现代化水平,从水资源保障、用水效率、水资源保护、水资源公共管理能力、水资源支撑能力5个方面构建评价指标体系,将模糊层次分析法(FAHP)和熵权法耦合,确定评价指标综合权重,基于物元理论建立水资源管理现代化评价模型。以南京市高淳区为例进行评价,结果表明,南京市高淳区水资源现代化管理水平处于初等现代化阶段,与实际情况相符,验证了所构建评价模型的可行性和有效性。     

熵权-云模型在土石坝安全综合评价中的应用

提出了一种基于熵权-云模型的方法,借鉴云模型的特点,在构建评价层次结构模型时,采用改进层次分析法结合信息熵确定各评价指标权重,以克服运用模糊层次综合分析法时权重受人为主观判断影响较大和模糊概念会丢失部分不确定性等问题,改进隶属函数对土石坝进行综合评价,并以某均质土石坝为例评价了大坝安全状态,分析表明该方法具有可行性。     

HEGM: A hierarchical elastic graph matching for hand gesture recognition

A hierarchical scheme for elastic graph matching applied to hand gesture recognition is proposed. The proposed algorithm exploits the relative discriminatory capabilities of visual features scattered on the images, assigning the corresponding weights to each feature. A boosting algorithm is used to determine the structure of the hierarchy of a given graph. The graph is expressed by annotating the nodes of interest over the target object to form a bunch graph. Three annotation techniques, manual, semi-automatic, and automatic annotation are used to determine the position of the nodes. The scheme and the annotation approaches are applied to explore the hand gesture recognition performance. A number of filter banks are applied to hand gestures images to investigate the effect of using different feature representation approaches. Experimental results show that the hierarchical elastic graph matching (HEGM) approach classified the hand posture with a gesture recognition accuracy of 99.85% when visual features were extracted by utilizing the Histogram of Oriented Gradient (HOG) representation. The results also provide the performance measures from the aspect of recognition accuracy to matching benefits, node positions correlation and consistency on three annotation approaches, showing that the semi-automatic annotation method is more efficient and accurate than the other two methods.     

Runtime home mapping for effective memory resource usage

In tiled Chip Multiprocessors (CMPs) last-level cache (LLC) banks are usually shared but distributed among the tiles. A static mapping of cache blocks to the LLC banks leads to poor efficiency since a block may be mapped away from the tiles actually accessing it. Dynamic policies either rely on the static mapping of blocks to a set of banks (D-NUCA) or rely on the OS to dynamically load pages to statically mapped addresses (first-touch).     

Electrochromic WO3−x films with reduced lattice deformation stress and fast response time

Electrochromic properties of electrochemically deposited and etched (EDE) WO_3−x films have been investigated using voltammetry and nanogravimetry to elucidate the amount of residual stress associated with lattice polarization and deformation in WO_3−x nanoparticles. The cathodic WO_3−x deposition from pertungstic acid solution and unusual properties of the cathodic electroetching of the oxide in tetraethyl ammonium chloride solution are reported and elucidated on the basis of Electrochemical Quartz Crystal Nanogravimetry (EQCN) measurements. The stress enhanced resonant frequency shift was observed upon WO_3−x film coloration. However, the stress enhancement appeared to be much lower (up to 4-6 times) than that measured for films synthesized by other methods. The stress reduction in WO_3−x films under study has been attributed to the stress relaxing propensity of EDE film to suppress the compressive stress wave. A considerable isotopic effect has been observed in nanogravimetry of the H⁺ and D⁺ ion intercalation into WO_3−x films. We have found that the isotopic effect is primarily due to the true mass loading difference between hydrogen and deuterium ions, for the same concentration of color centers (2.65 × 10²¹ cm⁻³), since EQCN frequency shifts associated with stress in the film for H⁺ and D⁺ are very close to each other.