Preparation and characterization of transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency

Transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency were reported in this paper. First, zinc oxide (ZnO) precursor was synthesized via the homogeneous precipitation method and ZnO nanoparticles were then made by calcination of the precursor at different temperature. The structural properties of the as-prepared ZnO nanoparticles were studied in detail using thermogravimetry (TGA), differential thermal analysis (DTA), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM), respectively. Transparent ZnO/epoxy nanocomposites were subsequently prepared from transparent epoxy (EP-400) and as-prepared ZnO nanoparticles via in situ polymerization. Optical properties of ZnO/epoxy nanocomposites, namely visible light transparency and UV light shielding efficiency, were studied using an ultraviolet-visible (UV-vis) spectrophotometer. The optical properties of the as-obtained nanocomposites were shown to depend on ZnO particle size and content. The nanocomposite containing a very low content (0.07% in weight) of ZnO nanoparticles with an average particle size of 26.7 nm after calcination at 350 °C possessed the most optimal optical properties, namely high-visible light transparency and high-UV light shielding efficiency, that are desirable for many important applications.     

基于区域极点约束的鲁棒H2控制

考虑了在区域极点约束下状态反馈的鲁棒H2控制问题.分别对含多面体不确定性的连 续和离散系统进行了讨论.基于LMI,给出了存在参数相关的Lyapunov矩阵的充分条件.利用 LMI凸优化方法的解,所得静态反馈控制器,不仅保证闭环系统的极点在-给定区域内,而且还 使性能指标H2的一上界达到最小.     

Power Supply Noise Aware Task Scheduling on Homogeneous 3D MPSoCs Considering the Thermal Constraint

Thanks to the emerging 3D integration technology, The multiprocessor system on chips (MPSoCs) can now integrate more IP cores on chip with improved energy efficiency. However, several severe challenges also rise up for 3D ICs due to the die-stacking architecture. Among them, power supply noise becomes a big concern. In the paper, we investigate power supply noise (PSN) interactions among different cores and tiers and show that PSN variations largely depend on task assignments. On the other hand, high integration density incurs a severe thermal issue on 3D ICs. In the paper, we propose a novel task scheduling framework considering both the PSN and the thermal issue. It mainly consists of three parts. First, we extract current stimuli of running tasks by analyzing their power traces derived from architecture level simulations. Second, we develop an efficient power delivery network (PDN) solver to evaluate PSN magnitudes efficiently. Third, we propose a heuristic algorithm to solve the formulated task scheduling problem. Compared with the state-of-the-art task assignment algorithm, the proposed method can reduce PSN by 12% on a 2 × 2 × 2 3D MPSoCs and by 14% on a 3 × 3 × 3 3D MPSoCs. The end-to-end task execution time also improves as much as 5.5% and 7.8% respectively due to the suppressed PSN.     

Active detumbling technology for high dynamic non-cooperative space targets

Multibody System Dynamics - High dynamic non-cooperative space targets generally perform complex motions with large angular velocities, so capturing these targets directly may cause fracture damage...     

Asymptotical Synchronization of Chaotic Lur’e Systems Under Time-Varying Sampling

This paper investigates the problem of sampled-data synchronization of chaotic Lur’e systems with time-varying sampling. A novel Lyapunov functional, which is continuous in time and makes full use of the available information about the sampling pattern, is constructed to synchronize the chaotic Lur’e systems. By using a free-weighting matrix approach and solving a set of linear matrix inequalities (LMIs), a sampled-data controller is obtained. The effectiveness and the validity of the proposed theoretical result are illustrated by two numerical examples.     

Window Detection in Facades Using Heatmap Fusion

Journal of Computer Science and Technology - Window detection is a key component in many graphics and vision applications related to 3D city modeling and scene visualization. We present a novel...     

Facile synthesis of antimony-doped tin oxide nanoparticles by a polymer-pyrolysis method

In this article, antimony-doped tin oxide (ATO) nanoparticles was synthesized by a facile polymer-pyrolysis method. The pyrolysis behaviors of the polymer precursors prepared via in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry (TG-DSC). The structural and morphological characteristics of the products were studied by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). The results reveal that the ATO nanoparticles calcined at 600 °C show good crystallinity with the cassiterite structure and cubic-spherical like morphology. The average particle size of ATO decreases from 200 to 15 nm as the Sb doping content increases from 5 mol% to 15 mol%. Electrical resistivity measurement shows that the resistivity for the 10-13 mol% Sb-doped SnO₂ nanoparticles is reduced by more than three orders compared with the pure SnO₂ nanoparticles. In addition, due to its versatility this polymer-pyrolysis method can be extended to facile synthesis of other doped n-type semiconductor, such as In, Ga, Al doped ZnO, Sn doped In₂O₃.     

Transpiration cooling of a nose cone by various foreign gases

The transpiration cooling mechanisms used for thermal protection of a nose cone was investigated experimentally and numerically for various cooling gases. The effects of injection rates, model geometry, inlet temperature and Reynolds number of the main stream were studied for air, nitrogen, argon, carbon dioxide and helium. The experiments used a hot gas wind tunnel with T_∞ = 375 K and 425 K and Re_∞ = 4630–10,000. The experimental results indicated that even a small amount of coolant injection drastically reduced the heat transfer from the hot gases with the cooling effectiveness increasing with increasing injection rate, although the increases became smaller as the gas injection rate was further increased. The temperature and cooling effectiveness distribution along the transpiration surface of the nose cone model exhibited similar tendencies for all the coolants employed in present experimental research. The temperature decreased from the stagnation point towards the downstream region, then increased because of the non-uniform mass flow distribution of the coolant and thermal conduction from the metal backplane, whereas the cooling effectiveness variation was the reverse. The local cooling effectivenesses and thermal capacities were found to depend on the coolant thermophysical properties. Two-dimensional numerical simulations using the RNG κ?ε turbulence model for the main stream flow and the Darcy–Brinkman–Forchheimer momentum equations and thermal equilibrium model for the porous zone compared well with the general features in the experiments.     

磁化焙烧对鲕状赤铁矿可磨性的影响

研究了磁化焙烧条件对鄂西铁矿磨矿性能的影响,通过粒度测定、可磨度测定,对比了不同焙烧条件下矿石可磨性之间的差异。结果显示：经焙烧处理后,矿石粒度组成中粗颗粒会增多,细颗粒会减少;焙烧产品的可磨度因焙烧条件不同而不同,按照焙烧温度、保温时间、配煤量的顺序对可磨度的影响依次减弱,最利于磨矿的焙烧条件为：焙烧温度900 ℃,焙烧时间2 h,配煤量5%。