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31.
In this paper we study the robustness of strong stability of a discrete semigroup on a Hilbert space under bounded perturbations. As the main result we present classes of perturbations preserving the strong stability of the semigroup. 相似文献
32.
大容积无缝钢瓶、管柬式集装箱和长管拖车作为专用气体储运装备在我国使用和制造已有10年时间,在检验检测和安全监管方面已基本形成相应的安全规范,但设计制造缺乏标准支撑。本文对管柬式集装箱的设计制造资质、组装工艺和型式试验要求进行简要介绍,包括大容积无缝钢瓶和长管拖车的相应要求。 相似文献
33.
F.J. Pérez-Alonso C. AdánS. Rojas M.A. PeñaJ.L.G. Fierro 《International Journal of Hydrogen Energy》2014
A series of Ni/Fe electrodes have been prepared by electrodeposition of metal salt precursors on different substrates. The surface morphology, chemical composition and electrochemical characteristics of these electrodes were studied by various physico-chemical techniques such as X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The electrochemical properties of the electrodes were examined by steady-state polarization curves. First, the influence of features such as Ni/Fe composition and type of substrate for the oxygen evolution reaction (OER) were determined by electrochemical techniques in a conventional 3-electrodes cell. The overpotential for the OER is lower for the electrodes with the higher concentrations of Ni. The electrodes with a Ni/Fe composition of 75/25 wt.% electrodeposited on steel mesh and/or 75/25 and 50/50 wt.% on nickel foam result in the most active configurations for the OER. These electrodes were further tested as anodes for alkaline water electrolysis during at least 70 h. In order to understand their activity and stability, the used electrodes were also characterized by SEM and compared to the fresh electrodes. Among the compositions and substrates examined, the Ni50Fe50-Nf electrode exhibited the lowest overpotential (2.1 V) for the OER and the higher stability as anode in an alkaline water electrolysis cell. 相似文献
34.
We present the design of a formal low-level multithreaded language with advanced region-based memory management and thread synchronization primitives, where well-typed programs are memory safe and race free. In our language, regions and locks are combined in a single hierarchy and are subject to uniform ownership constraints imposed by this hierarchical structure: deallocating a region causes its sub-regions to be deallocated. Similarly, when a region is read/write-protected, then its sub-regions inherit the same access rights. We discuss aspects of the integration and implementation of the formal language within Cyclone and evaluate the performance of code produced by the modified Cyclone compiler against highly optimized C programs using pthreads. Our results show that the performance overhead for guaranteed race freedom and memory safety is in most cases acceptable. 相似文献
35.
Roman A. Sidorov Vasily P. Pchelkin Anatoly V. Zhukov Andrei G. Vereshchagin Vladimir D. Tsydendambaev 《Journal of the American Oil Chemists' Society》2014,91(12):2053-2063
Positional‐species composition (PSC) of 1,2,3‐triacyl‐sn‐glycerols (TAG) from the arils of mature fruits of 13 species of Euonymus L. genus was established. The residues of six major fatty acids (FA), palmitic, stearic, hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic, were present in the TAG. PSC of TAG was determined by their partial lipase hydrolysis. By using hierarchical cluster and principal component analyses, it was definitely demonstrated that separate taxonomic units forming this genus were significantly distinguished as regards PSC of TAG. In particular, the Euonymus subgenus greatly exceeded the Kalonymus subgenus in both total content of L in TAG and in the rate of its incorporation into their mid‐position, while TAG of Kalonymus were marked by a prevalence of O‐TAG and sn‐2‐O isomers. Thus, these subgenera were significantly distinct in the rate of incorporation of O and L residues in the sn‐2 position of TAG molecules. Meanwhile, the TAG from the Euonymus section species were marked by an enhanced concentration of H and the incorporation of H in UUU TAG was much more active than in other TAG types. As for positional‐type composition of TAG, saturated FA were always virtually absent in the sn‐2 position of Euonymus aril TAG. 相似文献
36.
我国曾长期是一个农业社会,农
村是整个社会的主体,尽管现在仍处在向
城市时代过渡的高峰期,但乡村规划及其建
设依然具有重要意义。综合各种情况,接续
型乡村规划应成为当代中国乡村规划的主流
模式。这种兼顾继承与创新的规划,具有
延续文脉、有机更新、成本低廉等优势。在
运用该种规划模式时,要尊重乡村的内在空
间肌理及历史沿革,突出与彰显人文特征,
使用与乡村规模相适宜的小尺度,关注乡村
社会经济的当代转型等。 相似文献
37.
孔庆良 《自动化与仪器仪表》2012,(5):92-94
西门子高级编程指令为实现复杂的控制功能提供了保证.本文以ANY参数类型为主,结合PROFIBUS-DP主从通讯的案例,讲解了如何构造ANY类型的参数变量,最终实现模块化编程. 相似文献
38.
《国际计算机数学杂志》2012,89(4):709-713
Let S be a semigroup. We consider the relation γ and its transitive closure γ*. The relation γ is the smallest equivalence relation on S so that S/γ* is a commutative semigroup. Based on the relation γ, we define a neighbourhood system for each element of S, and we present a general framework of the study of approximations in semigroups. The connections between semigroups and operators are examined. 相似文献
39.
Most patients with severe Type II diabetes mellitus, characterised by both insulin resistance and β‐cell failure, eventually require insulin therapy. According to the nonlinear dynamics of homeostasis of blood glucose, proportional‐integral (PI) controller, modified by penalising the feedback error using a fuzzy inference system has been developed to maintain normoglycaemia in a simulated patient using a closed‐loop insulin infusion pump. The simulation employs a compartment model proposed by Vahidi et al. [Vahidi et al., Biochem. Eng. J. 2011, 55(1), 7–16]. The results demonstrate that the fuzzy‐based PI controller is superior to a conventional PI controller for the regulation of blood glucose by insulin infusion for Type II diabetic patients. © 2012 Canadian Society for Chemical Engineering 相似文献
40.
文章由中国传统轴对称院落的布局要旨出发.建构了相应的院落分类基本框架.为更为深入细致地研究传统建筑提供合理的基础。 相似文献