共查询到20条相似文献,搜索用时 31 毫秒
1.
为了减轻机场跑道除胶工作人员的劳动强度,提高除胶工作效率,文章提出了一种基于机器视觉的胶痕自动查找和识别方法,设计了基于ARM单片机控制的图像无线采集和基于PC机控制的图像接收、图像预处理和图像识别系统。文章通过分析预处理后的数据特点,确定了基于细胞神经网络算法的胶痕识别算法,然后在MATLAB仿真环境下确定了该算法的最优模型和参数,最后在Visual C++ 6.0环境下完成了该算法的程序编译,调试并完成了对胶痕的自动识别过程。理论仿真和程序测试的结果证明了文章提出的方法在胶痕自动识别系统中的可行性,也为机场特种设备的无人化和智能化提供了参考。 相似文献
2.
用高温熔融法合成了Ca和Ce复合填充的单相p型CamCenFexCo4-xSb12化合物,探索了两种原子复合填充对其热电性能的影 响规律.研究结果表明,填充分数相同时,Ca和Ce两种原子复合填充的p型CamCe nFexCo4-xSb12化合物的载流子浓度和电 导率介于Ca或Ce一种原子单独填充的化合物之间,且随两种原子填充分数m+n的增加而降低 ;赛贝克系数随两种原子填充总量,尤其是Ce填充分数m的增加以及温度的上升而增加;在 相同填充分数时,两种原子复合填充的p型CamCenFexC o4-xSb12化合物的晶格热导率较Ca或Ce一种原子单独填充的化合物 的晶格热导率低,当总填充分数m+n为0.3左右,且Ca和Ce的填充量大致相等时,化合物的晶 格热导率最低.p型Ca0.18Ce0.12Fe1.45Co2.55 sub>Sb12.21化合物的最大热电性能指数ZT值在750K时达到1.17.
关键词:
skutterudite化合物
双原子复合填充
合成
热电性能 相似文献
3.
4.
本文中研究了C-15结构V2Hf1-xNbx,V2Zr1-xNbx和V2Hf0.5Zr0.5-xNbx系列的超导转变温度Tc与Nb合量x的关系,发现V2Zr,V2Hf加Nb后与V2Hf0.5Zr0.5加Nb后性能显著不同。测定了V2Zr,V2Hf和V2Hf0.5Zr0.5的X射线光电子能谱。结果表明,当Hf原子和Zr原子共存于AB2化合物的A位上时,发生了一种增强原子间相互作用的新的电荷转移。这个事实支持由角动量分波表象能带论方法分析电声耦合超导原理的结果对四元V2(HfZrNb)系列的超导行为提出的一种可能解释:4d-5d原子配位可能有助于提高4d导带的杂化程度,从而有利于提高超导Tc。
关键词: 相似文献
5.
A.L. Vasiliev E.A. Stepantsov Z.G. Ivanov E. Olsson K. Verbist G. Van Tendeloo 《Interface Science》1997,5(4):223-230
The structure of the artificial grain boundaries in Al2O3 bicrystals withY3Al5O12 and Y-stabilizedZrO2 (Y-ZrO2) intermediate layers was studiedwith high resolution electron microscopy, electron diffraction and energydispersive X-ray analysis. TheY3Al5O12 intermediate layer wasfound to be polycrystalline with three different orientation relationshipsbetween the 2O3 and theY3Al5O12. The structure of theY3Al5O12/2O3 interfaces is described.Also2O3 bicrystals with an Y-ZrO2/2O3/Y-ZrO2/2O3/Y-ZrO2intermediate layer, prepared at two different temperatures, werestudied.Recry stallization of the intermediate layers occurred during thesolid phase intergrowth of the 2O3 bicrystalsparts and only an Y-ZrO2 layer was found as intermediatelayer. The misorientation between the consecutive Y-ZrO2grains was less than 1.5°. Misfit dislocations and atomic height stepsdecorate the Y-ZrO2/2O3interface. 相似文献
6.
C.D. Spencer P.A. Smith R.P. Stillwell 《Journal of Physics and Chemistry of Solids》1978,39(2):103-106
The Mössbauer determined cation distributions of FeV2O4, FeCr2O4, FeMn2O4, Fe3O4, FeCo2O4, CoV2O4, CoCr2O4, CoMn2O4, CoFe2O4 and Co3O4 are compared with the quantitative d-orbital stablization energies of McClure and of Dunitz and Orgel. They are also compared with the qualitative ligand field stabilization energies of Cotton. These theories do not account for observation in the cases of FeMn2O4, FeCo2O4 and CoFe2O4. 相似文献
7.
Photocatalytic activity of Nb2O5/SrNb2O6 heterojunction on the degradation of methyl orange 总被引:1,自引:0,他引:1
Jingcheng Xing Zhichao Shan Jianjiang Bian Wendeng Wang 《Journal of Physics and Chemistry of Solids》2008,69(1):23-28
The pure SrNb2O6 powders were prepared at 1400 °C by a conventional solid-state method and characterized by X-ray powder diffraction and UV-vis diffuse reflection spectrum. The powders of Nb2O5 and SrNb2O6 were ball-milled together and annealed to form the Nb2O5/SrNb2O6 composite. Photocatalytic activities of the composites were investigated on the degradation of methyl orange. The results show that the proportion of Nb2O5 to SrNb2O6 and the annealing temperature greatly influence the photocatalytic activities of the composites. The best photocatalytic activity occurs when the weight proportion of Nb2O5 to SrNb2O6 is 30% and the annealing temperature is 600 °C. The tremendously enhanced photocatalytic activity of the Nb2O5/SrNb2O6 composite compared to Nb2O5 or SrNb2O6 is ascribed to the heterojunction effect taking place at the interface between particles of Nb2O5 and SrNb2O6. The powders also show a higher photocatalytic activity than commercial anatase TiO2. 相似文献
8.
This work is devoted to the study of and Rb2UO2F4.H2O and Cs2UO2F4. H2O IR-spectra with the aim of obtaining a set of vibration frequencies characterising M2U02F4.H2O complexe elucidating the role and nature of water bonds in the structures of the above-mentioned compounds; and receiving preliminary information on the structure of M2UO2F4.H2O. The investigated compounds were synthesized in accord with our previous paper1. M2UO2D2O and M2UO2F4.HDO were obtained by recrystallizing M2UO2F4.H2O from D2O and HDO respectively 相似文献
9.
Yu. E. Kalinin M. A. Kashirin V. A. Makagonov S. Yu. Pankov A. V. Sitnikov 《Physics of the Solid State》2017,59(1):21-27
This work considers the effect of vacuum annealing on the thermoelectric properties of Sb0.9Bi1.1Te2.9Se0.1 thin film and Sb0.9Bi1.1Te2.9Se0.1–C composites with various carbon contents produced by ion-beam deposition in an argon atmosphere. The electrical resistivity and the thermopower of Sb0.9Bi1.1Te2.9Se0.1–C nanocomposites are found to be dependent on not only the carbon concentration but also the type and the concentration of intrinsic point defects of the Sb0.9Bi1.1Te2.9Se0.1 solid solution, which determine the type of conductivity of Sb0.9Bi1.1Te2.9Se0.1 granules. The power factors are estimated for films of Sb0.9Bi1.1Te2.9Se0.1 solid solution and films of Sb0.9Bi1.1Te2.9Se0.1–C composites and found to have values comparable with the values for nanostructured materials on the basis of (Bi,Sb)2(Te,Se)3 solid solutions. 相似文献
10.
In this article, the isomerisation mechanisms of HN(NO2)2 to O2NNN(O)OH without and with catalyst X (X = H2O, (H2O)2, (H2O)3, HCOOH, H2SO4, CH3CH2COOH and HN(NO2)2) have been investigated theoretically at the CBS-QB3 level of theory. Our results show that the catalyst X (X = H2O, (H2O)2, (H2O)3, HCOOH, H2SO4 and CH3CH2COOH) shows different positive catalytic effects on reducing the apparent activation energy of the isomerisation reaction processes. Such different catalytic effects are mainly related to the number of hydrogen bonds and the size of the ring structure in X (X = H2O, (H2O)2 and (H2O)3)-assisted transition states, as well as different values of pKa for H2SO4, HCOOH and CH3CH2COOH. Very interesting is also the fact that H2SO4-assisted reaction is the most favourable for the hydrogen transfer from HN(NO2)2 to O2NNN(O)OH, due to the smallest pKa (?3.0) value of H2SO4 than H2O, HCOOH, H2SO4 and CH3CH2COOH, and also because of the largest ∠X???H???Y (the angle between the hydrogen bond donor and acceptor) involved in H2SO4-assisted transition state. Compared to the self-catalysis of the isomerisation mechanisms of HN(NO2)2 to O2NNN(O)OH, the apparent activation energy of H2SO4-assisted channel also reduces by 9.6 kcal?mol?1, indicating that H2SO4 can affect the isomerisation of HN(NO2)2 to O2NNN(O)OH, most obvious among all the catalysts H2O, (H2O)2, (H2O)3, HCOOH, H2SO4, CH3CH2COOH and HN(NO2)2. 相似文献
11.
Shanhua Chen Shihu Han Yanhui Chen Dengpan Xue Xiaodong Zhu 《Composite Interfaces》2018,25(11):1019-1038
The Mg2B2O5 whiskers (Mg2B2O5w) were modified by boric acid ester (BE) coupling agent and used to prepare polycarbonate (PC) composites. Surface wettability test and evaluation of dispersibility of BE-modified Mg2B2O5w (BE-Mg2B2O5w) in n-heptane were carried out by water contact angle measurement and polarizing microscopy, respectively. The surface chemical characteristics of BE-Mg2B2O5w and estimation of the amount of tightly bonded organic modifier were examined by Fourier transform infrared spectrometry (FT-IR) and thermogravimetric analysis (TGA), respectively. The influence of BE-Mg2B2O5w on the mechanical property, morphology and thermostability of PC composites was investigated by using universal testing machine, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and TGA, respectively. It was found that BE was successfully grafted to the surface of Mg2B2O5w, and the hydrophobic BE-Mg2B2O5w leads to high ratio of adhesion work to interfacial tension between PC and BE-Mg2B2O5w, and its better dispersibility in n-heptane. Furthermore, the incorporation of BE-Mg2B2O5w into PC matrix resulted in higher tensile properties of PC/BE-Mg2B2O5w than that of PC/Mg2B2O5w composites and lower maximum weight loss rate than that of PC. The storage modulus of the PC/Mg2B2O5w composites increased obviously as a function of whisker content, especially for the composites with BE-Mg2B2O5w, but the Tg value changed little. 相似文献
12.
The Raman spectroscopy technique was used to characterize the microstructure and the crystallization properties of the as‐cast and heat‐treated binary TeO2 WO3, TeO2 CdF2 and ternary TeO2 CdF2 WO3 glasses and glass ceramics. The results were compared with those obtained by using the X‐ray diffraction technique. The effect of the WO3 and CdF2 contents on the TeO2 glass network and the intensity ratios of the deconvoluted Raman peaks were determined. The shifts in the Raman band wavenumbers and the intensity values for each band were investigated. The Raman results indicated that the glasses were mainly formed by the [TeO4] and [TeO3] units. The [TeO4] units convert to [TeO3] units with the addition of WO3 and CdF2 into tellurite glasses. All the crystalline phases such as α‐TeO2, δ‐TeO2 and γ‐TeO2 existing in the TeO2 WO3, TeO2 CdF2 and TeO2‐ WO3 CdF2 glasses were determined. The transformation of the metastable γ‐TeO2 phase into stable α‐TeO2 was observed for the (1 − x)TeO2 xWO3 (where x = 0.15, 0.20, 0.25), 0.90Te2 0.10CdF2, the 0.85TeO2 0.10CdF2 0.05WO3 and 0.80TeO2 0.10CdF2 0.10WO3 glasses, and the transformation of the metastable δ‐TeO2 phase into the stable α‐TeO2 was also observed for the TeO2 CdF2 WO3 glass system. In addition, an unidentified phase formation, labeled ε, was determined. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
13.
包钴型γ-Fe2O3磁粉分为包钴γ-Fe2O3(简记为Co-γ-Fe2O3)和包钴包亚铁γ-Fe2O3(简记为CoFe-γ-Fe2O3)两种,它们的矫顽力可比γ-Fe2O3磁粉的提高100至400Oe左右,本工作对这两种磁粉矫顽力增大的原因作了探讨,认为它们矫顽力增大的机制不同:CO-γ-Fe2O3矫顽力增大是由于表面包覆一层Co(OH)2使表面各向异性增大,而CoFe-γ-Fe2O3则是由于表面包覆的是钴铁氧体,γ-Fe2O3与钴铁氧体之间发生耦合作用,使矫顽力增大。 相似文献
14.
A detailed Mössbauer investigation of 1 : 1 SrO : Fe2O3 has shown that a single phase with the SrFe2O4 composition does not exist in the SrO-Fe2O3 system when SrCo3 and Fe2O3 are reacted in air. A multiphase assemblage of SrFe12O19, Sr4Fe6O13, and SrFeO3-x is observed in the material with an overall composition of “SrFe2O4”. By means of novel analyses of the complex Mössbauer spectra of the 1 : 1 SrO : Fe2O3 composition, all of the Fe containing phases have been identified and their respective mole percentages determined. The relative amounts of the phases present depend on the final firing temperature. The published X-ray powder data for “SrFe2O4” can be interpreted satisfactorilly in terms of the Mössbauer results, i.e., as a multiphase assemblage, and corresponds to a low temperature assemblage of SrFe12O19, Sr4Fe6O13 and SrFeO3-x for the overall composition of “SrFe2O4”. 相似文献
15.
Yumin Liu Aili Wang Dongzhi Zhang Chunyan Liu Jun Chen Hui Feng Hengping Yao Tingshun Jiang 《Applied Surface Science》2008,254(9):2809-2819
SiO2-coated TiO2 powders were prepared by the chemical deposition method starting from rutile TiO2 and Na2SiO3. The SiO2-coated TiO2 powders were characterized by X-ray photoelectron spectroscopy, Zeta-potential analysis, Fourier transform infrared spectroscopy, and transmission electron microscopy. The evolution of island-like and uniform coating layers was found to depend upon the ratio of Na2SiO3 to TiO2, reaction temperature, and pH. The whiteness and brightness of the SiO2-coated TiO2 powders increased in response to an increase in the SiO2 loading, but there was a maximum value among the light scattering indexes. The SiO2-coated TiO2 powders possessed more negative Zeta potentials than the naked TiO2. The dispersibility of the SiO2-coated TiO2 powders with the continuous and uniform SiO2 coating layers was higher than that of the naked TiO2 and the SiO2-coated TiO2 powders with the island-like SiO2 coating layers. 相似文献
16.
The effect of Fe on the phase and magnetocaloric property of LaFe11.6*xSi1.4B0.1 alloys with x = 1.0–1.4 have been studied. The results show that the excess of Fe will make the α-Fe phases increase, but the easy corrosion LaFeSi phase reduces in LaFe11.6*xSi1.4B0.1 alloys. All LaFe11.6*xSi1.4B0.1 alloys keep the first-order magnetic phase transition. The saturation magnetizations of LaFe11.6*xSi1.4B0.1 alloys with x > 1 are much higher than LaFe11.6Si1.4B0.1 alloy under 2T magnetic field. This results in the maximum isothermal magnetic entropy changes, and the relative cooling power of LaFe11.6*xSi1.4B0.1 alloys is bigger than for LaFe11.6Si1.4B0.1 alloys. 相似文献
17.
18.
Interfacial reactions and oxidation behavior of Al2O3 and Al2O3/Al coatings on an orthorhombic Ti2AlNb alloy 总被引:1,自引:0,他引:1
The uniform and dense Al2O3 and Al2O3/Al coatings were deposited on an orthorhombic Ti2AlNb alloy by filtered arc ion plating. The interfacial reactions of the Al2O3/Ti2AlNb and Al2O3/Al/Ti2AlNb specimens after vacuum annealing at 750 °C were studied. In the Al2O3/Ti2AlNb specimens, the Al2O3 coating decomposed significantly due to reaction between the Al2O3 coating and the O-Ti2AlNb substrate. In the Al2O3/Al/Ti2AlNb specimens, a γ-TiAl layer and an Nb-rich zone came into being by interdiffusion between the Al layer and the O-Ti2AlNb substrate. The γ-TiAl layer is chemically compatible with Al2O3, with no decomposition of Al2O3 being detected. No internal oxidation or oxygen and nitrogen dissolution zone was observed in the O-Ti2AlNb alloy. The Al2O3/Al/Ti2AlNb specimens exhibited excellent oxidation resistance at 750 °C. 相似文献
19.
The electronic structures of the closo-carboranes 1,5-C2B3H5, 1,2-C2B4H6, 1,6-C2B4H6 and 2,4-C2B5H7 are discussed using the results of ab initio calculations in both minimal and extended bases of contracted gaussian type functions fitted to Slater type orbitals. A comparison is made with the results from semi-empirical INDO calculations, and the bonding in 1,7-C2B6H8, 1,6-C2B7H9, 5,9-C2B7H13, 1,6-C2B8H10 and the 1,2-, 1,7- and 1,12-isomers of C2B10H12 studied using the latter method. The delocalized molecular orbitals from both the ab initio and semi-empirical calculations are transformed to localized orbitals to provide an analysis of the multi-centre bonding in these electron-deficient molecules, which requires no prior assumptions about the nature of the bonding. 相似文献
20.
Hybrid organic-inorganic perovskite materials have obtained considerable attention due to their exotic optoelectronic properties and extraordinarily high performance in photovoltaic devices. Herein, we successively converted the ultrathin PbI2/MoS2 into the CH3NH3PbI3/MoS2 heterostructures via CH3NH3I vapor processing. Atomic force microscopy (AFM)、Scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS) measurements prove the high-quality of the converted CH3NH3PbI3/MoS2. Both MoS2 and CH3NH3PbI3 related photoluminescence (PL) intensity quenching in CH3NH3PbI3/MoS2 implies a Type-II energy level alignment at the interface. Temperature-dependent PL measurements show that the emission peak position shifting trend of CH3NH3PbI3 is opposite to that of MoS2 (traditional semiconductors) due to the thermal expansion and electron-phonon coupling effects. The CH3NH3PbI3/TMDC heterostructures are useful in fabricating innovative devices for wider optoelectronic applications. 相似文献