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971.
972.
973.
针对无监督学习网络模型对于特定的映射空间,期望产生特定的影响具有一定的局限性,提出了有监督的可生长结构的动态结构模型;该模型将动态结构模型与径向基函数网络结构有机结合,采用的是需要时生长的自组织生长算法,通过插入新的神经元、改变竞争层神经元间的连接以及调整层与层的连接权值,达到模型输出的精度要求,有效地解决了在输入特定的网络数据时,能产生期望的输出;该模型应用于两轮平衡机器人的平衡控制,经过仿真实验表明,该动态结构模型能够实现对两轮平衡机器人的平衡控制,且有一定的抗干扰性和实用价值。 相似文献
974.
Hansen JO Huo P Martinez U Lira E Wei YY Streber R Laegsgaard E Hammer B Wendt S Besenbacher F 《Physical review letters》2011,107(13):136102
We have studied the interaction of ethanol with reduced TiO(2)(110)-(1 × 1) by high-resolution scanning tunneling microscopy (STM) measurements and density functional theory calculations. The STM data revealed direct evidence for the coexistence of molecularly and dissociatively adsorbed ethanol species on surface Ti sites. In addition, we found evidence for dissociation of ethanol at bridge-bonded O vacancies. The density functional theory calculations support these findings and rationalize the distinct diffusion behaviors of molecularly and dissociatively adsorbed ethanol species, as revealed in time-lapsed STM images. 相似文献
975.
SiC/W/Ir multilayer-coated grating for enhanced efficiency in 50-100 nm wavelength range in Seya-Namioka mount 总被引:1,自引:0,他引:1
A broadband [SiC/W/Ir](2) multilayer coating was deposited onto a diffraction grating to enhance the grating efficiency in the 50-100 nm wavelength range in a Seya-Namioka mount. The holographic ion-beam etched grating had a laminar profile with 1200 lines/mm. The coating was designed by using the subquarterwave multilayer theory. The measurement results show that the efficiency in the -1st diffraction order is greater than 9.3% throughout the wavelength range of 50-100 nm, which is obviously higher than that of single-layer gratings with SiC, Ir, or Au coatings. 相似文献
976.
We derive a reconstruction algorithm for refraction-contrast computed tomography (CT) using dark-field imaging (DFI) optics, which can extract refraction information by a single shot, from the ray equation in geometrical optics. The proposed algorithm is similar to the convolution reconstruction technique widely used in conventional CT. Thus, this algorithm can be implemented simply while also being fast and stable. To demonstrate its validity, we constructed the imaging system based on DFI optics composed of a transmission Laue-type angular analyzer at the vertical wiggler beamline BL-14C in KEK and performed a preliminary imaging experiment using a physical phantom to successfully obtain the DFI-CT image using the proposed algorithm. 相似文献
977.
978.
Lira E Wendt S Huo P Hansen JØ Streber R Porsgaard S Wei Y Bechstein R Lægsgaard E Besenbacher F 《Journal of the American Chemical Society》2011,133(17):6529-6532
The role of bulk defects in the oxygen chemistry on reduced rutile TiO(2)(110)-(1 × 1) has been studied by means of temperature-programmed desorption spectroscopy and scanning tunneling microscopy measurements. Following O(2) adsorption at 130 K, the amount of O(2) desorbing at ~410 K initially increased with increasing density of surface oxygen vacancies but decreased after further reduction of the TiO(2)(110) crystal. We explain these results by withdrawal of excess charge (Ti(3+)) from the TiO(2)(110) lattice to oxygen species on the surface and by a reaction of Ti interstitials with O adatoms upon heating. Important consequences for the understanding of the O(2)-TiO(2) interaction are discussed. 相似文献
979.
Tang D Zhang W Zhang Y Qiao ZA Liu Y Huo Q 《Journal of colloid and interface science》2011,356(1):262-266
We have synthesized a series of catalysts for epoxidation of styrene by immobilizing salicylaldimine transition metal (copper, manganese, and cobalt) complexes on mesoporous silica nanoparticles (MSNs) with diameters of 120-150 nm. The prepared catalysts are characterized by infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP), CHN elemental analysis, nitrogen adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These catalysts possess excellent catalytic efficiency in epoxidation of styrene when using tert-BuOOH (TBHP) as oxidant. Styrene shows a high conversion (~99%) as well as epoxide selectivity (~80%) over Cu-MSN catalysts, and high conversion (~99%) and moderate epoxide selectivity (~65%) over Mn-MSN and Co-MSN catalysts. The recycling experiment results indicate that these catalysts maintain catalytic activity even after being used for three cycles. Our results indicate that MSNs can serve as better catalyst supports. 相似文献
980.
A simple and sensitive method has been developed for simultaneous analysis of three catecholamines: dopamine (DA), epinephrine (EP) and norepinephrine (NE) in urine by capillary electrophoresis (CE) coupled with in-column fiber-optic light-emitting diode-induced fluorescence detection (ICFO-LED-IFD). Fluorescein isothiocyanate was used as the fluorescence tagged reagent for derivatization of DA, EP and NE. The CE conditions for separation of these catecholamines were systematically investigated. It was found that catecholamines could be more effectively separated by adding β-cyclodextin (β-CD) and acetonitrile (ACN) to a background electrolyte (BGE) of sodium borate. The migration times are 10.61, 10.83 and 11.14 min for DA, EP and NE, respectively and the catecholamines are completely separated within 11.5 min under the optimal condition of a BGE containing 10% v/v ACN, 20 mM β-CD and 20 mM sodium borate (pH 9.5), and an applied voltage of 13 kV. The relative standard deviations of migration time and peak area for these catecholamines are less than 0.16 and 2.0%, respectively. The limit of quantifications (LOQs) for DA, EP and NE are 3.5, 1.0 and 3.1 nM whereas the limit of detections (LODs) for DA, EP and NE are 1.0, 0.3 and 0.9 nM, respectively. Our proposed CE method provides low LOQ and LOD values. This CE-ICFO-LED-IFD methodology has been successfully applied to analyze catecholamines in human urine samples with good accuracy and satisfactory recovery. 相似文献