Delay-dependent robust stability for neutral systems with mixed discrete-and-neutral delays

This paper focuses on the problem of delay-dependent robust stability of neutral systems with different discrete-and neutral delays and time-varying structured uncertainties. Some new criteria are presented, in which some flee weighting matrices are used to express the relatiomhips between the terms in the Leibniz-Newton formula. The criteria include the information on the size of both neutral-and-discrete delays. It is shown that the present results also include the results for identical discrete-and-neutral delays as special cases.A numerical example illustrates the improvement of the proposed methods over the previous methods and the influences between the discrete and neutral delays.     

铱金属及其氧化物薄膜的制备与应用研究进展

铱及其氧化铱薄膜具有优良的耐腐蚀、抗氧化特性，同时也具有极好的电化学特性，这使它在电学、抗氧化涂层、催化领域都有广泛的应用。综述了近年来有关金属铱及其氧化铱薄膜的合成与制备技术的一些最新进展。总的来看，制备方法可分为物理法和化学法。其中物理法包括溅射法、激光熔蒸法；化学法包括金属有机化学沉积法、热分解法、电化学沉积法、溶胶凝胶法等，对各种制备方法进行了评述，同时对铱及其氧化铱薄膜的应用领域进行了综述，并对今后铱及其氧化铱薄膜的制备发展趋势进行了预测。     

Morphologies and Properties of Micro-Arc Oxidation on Plate and Cylinder 2024 Al Alloy

Samples with two different shapes of 2024 aluminum alloy were treated with micro-arc oxidation (MAO), and the formation process and mechanism of oxidation film was analyzed. The results show that different geometrical curvature of the material has an influence upon the uniformity of films and the corrosion-resistance.     

Influence of Si on Interfacial Combination of SiCp/Al-Mg-Si Composite

The scanning electron microscopy (SEM) analysis results of Si distribution in the interface between SiC reinforcements and aluminum matrix of a stir casting SiCp/Al-Mg-Si composite were presented. Results show that there is Si precipitation deposit on the interface of the composite and Si connects with SiC reinforcements in one side and connects with aluminum matrix in the other side. Si phase plays as a connecting bridge, which contributes to the interfacial combination of SiCp/Al composite.     

使用MCNP程序调整和优化启明星实验装置设计方案

用蒙特卡罗程序(MCNP)对验证ADS系统的启明星实验装置的设计方案进行了有效增殖因数(Keff)计算,并对与Keff密切相关的热区燃料元件栅距和热区厚度进行了最优参数的计算。结果表明,启明星实验装置的Keff能够达到设计的目标。     

基于提升小波和Context模型的图象无失真编码方案

文章讨论了提升小波变换的基本原理。并根据提升小波系数的特点,结合基于Context模型的熵编码,提出了一种新的无失真图象编码方案。该方案中,将提升小波系数的编码分为三部分考虑,即反映非零系数位置的SignificanceMap、反映非零系数幅值大小的MostSignificanceBits(MSB)符号流和去除了MSB的剩余二进制符号流。因为Signifi-canceMap和MSB符号流中存在较强相关性,提出了简单有效的Context模型对它们进行熵编码。而对去除了MSB的剩余二进制符号流,由于其相关性较弱,直接使用自适应算术编码。经过实验对比证明了该方案在无失真图象编码中的有效性。     

Construction and in vitro/in vivo evaluation of 17-allylamino-17-demethoxygeldanamycin (17AAG)-loaded PEGylated nanostructured lipid carriers

In this study, the PEGylated nanostructured lipid carriers (PEG-NLC) were constructed for the intravenous delivery of 17-allylamino-17-demethoxygeldanamycin (17AAG). 17AAG-PEG-NLC was successfully prepared by the method of emulsion evaporation at a high temperature and solidification at a low temperature using a mixture of glycerol monostearate and PEG₂₀₀₀-stearate as solid lipids, and medium-chain triglyceride as the liquid lipid. The results revealed that the morphology of the NLC was spheroidal. The particle size, zeta potential and entrapment efficiency for 17AAG-PEG-NLC were observed as 189.4?nm, ?20.2 mV and 83.42%, respectively. X-ray diffraction analysis revealed that 17AAG existed as amorphous structures in the nanoparticles. In the in vitro release study, the 17AAG from 17AAG-PEG-NLC exhibited a biphasic release pattern with burst release initially and sustained release afterwards. In addition, 17AAG-PEG-NLC showed a significantly higher in vitro antitumor efficacy and longer retention time in vivo than 17AAG solution. These results indicated that 17AAG-PEG-NLC may offer a promising alternative to the current 17AAG formulations for the treatment of solid tumors.     

Synthesis and curing of liquid crystalline epoxy resin based on asymmetric mesogen

A novel liquid crystalline epoxy resin (LCER) derived from asymmetric mesogen unit was synthesized. Its structure and liquid crystalline behavior were characterized by hydrogen nuclear magnetic resonance (H‐NMR), differential scanning calorimetry (DSC), polarized optical microscopy (POM). The results indicated that the LCER converted to a nematic phase at 85°C during heating and finally became isotropic at 145°C. The curing behavior and phase behavior of the LCER with 4,4′‐diaminodiphenyl methane and methyl hexahydrophthalic anhydride were also studied by DSC and POM, respectively. Their apparent activation energy (E_a) was evaluated according to the Ozawa's isoconversional method. The results suggested that autocatalytic reaction had occurred in these two systems. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of high hydrogen enrichment on the outer-shear-layer flame of confined lean premixed CH4/H2/air swirl flames

In this study, we investigated the H₂-induced transition of confined swirl flames from the “V” to “M” shape. H₂-enriched lean premixed CH₄/H₂/air flames with H₂ fractions up to 80% were conducted. The flame structure was obtained with Planar Laser-Induced Fluorescence (PLIF) of the OH radical. Flow fields were measured with Particle Image Velocimetry (PIV). It was observed that the flame tip in the outer shear layer gradually propagated upstream and finally anchored to the injector with the hydrogen fractions increase, yielding the transition from the “V” to “M” flame. We examined the flame structures and the flame flow dynamics during the transition. The shape transition was directly related to the evolution of the corner flame along the outer shear layer. With H₂ addition, the outer recirculation zone first appeared downstream where the corner flame started to propagate upstream; then, the recirculation zone expanded upward to form a stable “M” flame gradually. The flow straining was observed to influence the stabilization of the outer shear layer flame significantly. This study can be useful for the understanding of recirculation-stabilized swirling flames with strong confinement. The flame structure and the flow characteristics of flames with a high H₂ content are also valuable for model validation.