共查询到20条相似文献,搜索用时 559 毫秒
1.
初中物理:“水的热膨胀的特点”的演示在我数年的教学中一直没有做过,这主要是因为:当堂演示太费时间又和讲课配合不好,如让学生等着看实验结果,则大部同学感到索然无味,如不等结果而先讲其他内容,则又打乱了课堂的系统性。加以有些学校根本没有水的最大密度演示器,因之过去讲这一节时,往往只用挂图一讲了事。但后来在物理通报上看到一些老师对这个演示采取了各种不同的方法,从而取得了较好的成绩。为了提高教学质量,我把通报上前后所介绍的几种方法都做了几遍,从不断变换着的操作中给了我新的启示,我又用了 相似文献
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气体的压强与体积的关系的实验设计陈银潭(江苏兴化市合塔中学225742)实验目的探索气体的压强与体积的关系.方法一实验器材50ml玻璃注射器一只,彩色橡皮膜一块(或小气球).器材装置(图1)图1实验步骤h用橡皮膜做成直径约Zem的小气球,扎紧口后放人... 相似文献
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初中物理学上册第三章第35节大气压的一个实验是:水由喷嘴向压强较低的玻璃管中喷入(见原书图55)。这个实验如果没有抽气机,就很难做。我 相似文献
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Transition metal oxides are a class of materials that are vitally important for developing new materials with functionality and smartness. The unique properties of these materials are related to the presence of elements with mixed valences of transition elements. Electron energy-loss spectroscopy (EELS) in the transmission electron microscope is a powerful technique for measuring the valences of some transition metal elements of practical importance. This paper reports our current progress in applying EELS for quantitative determination of Mn and Co valences in magnetic oxides, including valence state transition, quantification of oxygen vacancies, refinement of crystal structures, and identification of the structure of nanoparticles. 相似文献
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M.H Frommer 《Surface science》1977,64(1):251-260
This paper describes an experimental study of the intermetallic compound CuAl2 using Auger electron spectroscopy (AES). Chemical effects in the CuAl2 spectrum are observed corresponding to energy shifts of the Cu and Al peaks and the appearance of a new peak for the compound. These results are found to be in good agreement with those obtained using the technique of soft X-ray emission spectroscopy (SXES). The origin of the new peak appears to be a transition from a hybridised s-d band localized at the Cu site in the compound to an Al core state. This gives a band-like contribution to the CuAl2 AES spectrum. 相似文献
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V. G. Nazin M. N. Mikheeva L. L. Lev V. A. Rogalev 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(1):17-20
The electronic structure of titanium with different oxidation levels of the surface was studied by photoelectron spectroscopy
and electron energy loss spectroscopy (EELS). The spectra of the valence band and the core level of Ti3p and EEL spectra were recorded for a titanium surface with oxidation exposures from 0.12 to 900 L at room temperature. In
general, the titanium oxidation process is similar to that for zirconium, which was investigated earlier; however, certain
features of the electronic structure that were not observed earlier were revealed for titanium. Even at high oxidation exposures
of ∼1000 L, both O2p valence band and valence band corresponding to titanium metal states were observed. During consecutive oxidation, one can
see four different positions of the Ti3p peak corresponding to titanium atoms with different valences. It is probable that, at the initial oxidation stage, islands
of complex composition oxide were formed on the surface and grew into the bulk during further oxidation. 相似文献
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《Applied Surface Science》1987,29(2):242-248
The growth of Cu film on MnO substrate at room temperature has been investigated using Auger electron spectroscopy. Analysis of the Auger peak intensity as a function of Cu coverage and comparison of the experimental results with predictions of a layer-by-layer growth model, suggest that, at least in the first 16 Å of coverage, the growth of copper takes place in a layer-by-layer mode, simultaneously with the diffusion of some copper in the MnO substrate. 相似文献
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M.L. Shek P.M. Stefan D.L. Weissman-Wenocur B.B. Pate I. Lindau W.E. Spicer V.S. Sundaram 《Surface science》1982,115(1):L86-L91
Photoemission and Auger electron spectroscopy on Pt0.98Cu0.02 show that the (110) face has over twice as much Cu surface segregation as the (111) face. The Cu 3d-derived surface “density of states” differ strikingly in peak shape and in width (by 0.5 eV). The centroids, compared with bulk Cu d states, are shifted by more than 0.3 eV towards the Fermi level. This is the first experimental correlation between surface segregation and surface bonding. 相似文献
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介绍了采用X射线光电子谱(XPS)等技术研究脉冲激光沉积在Ni、Mo、C、NaCl(100)表面的Cu、Au原子团簇的电子状态;结合Cu2p3/2 X射线光电子谱峰和Cu L3M4,5M4,5俄歇跃迁分离了电子结合能的初态和终态贡献,得出了它们随Cu表面浓度变化的关系,并对之作出了解释。使用XPS、RBS、TEM三项技术研究了Au在NaCl(100)表面的生长过程,通过计算得出了在不同表面浓度下Au原子团簇的平均高度和表面覆盖率。 相似文献
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胺化葡萄糖及其铜配合物的光谱特性 总被引:1,自引:0,他引:1
研究了胺化D-葡萄糖的FTIR,1H-NMR特性及其与Cu(Ⅱ)形成配合物的UV光谱。在FTIR谱中,与D-葡萄糖相比,在1 629~1 608 cm-1出现δNH吸收峰,说明D-葡萄糖与乙二胺发生了反应;在1H-NMR谱中,在δ4.82~4.79的化学位移分别对应于葡萄糖C1上的质子及与C1直接相连的乙二胺的氨基上的质子,表明反应时乙二胺取代了葡萄糖C1上的羟基,形成了胺化葡萄糖;在UV谱中,胺化葡萄糖在紫外光区并没有明显吸收,但与Cu(Ⅱ)形成配合物后,在236 nm附近出现最大吸收峰。在胺化葡萄糖-Cu(Ⅱ)配合物中,Cu2+与胺化葡萄糖的络合比接近于1∶1,该配合物稳定常数6.8×107 L·mol-1。 相似文献
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基于密度泛函理论, 采用第一性原理平面波超软赝势法, 对六方纤锌矿结构的ZnO晶体和Yb2+, Yb3+分别掺杂ZnO晶体进行几何优化, 并在此基础上计算得到了未掺杂ZnO晶体及不同价态Yb元素掺杂ZnO体系的空间结构、 能带、电子态密度及光学性质.结果表明: 掺杂后体系形成能减少, 稳定性增加, 并引入了Yb-4f杂质能级. 掺杂不同价态的Yb元素对能带结构产生了不同的影响, 并且都使体系的光学性质发生了明显变化.与纯ZnO相比, Yb2+, Yb3+ 分别掺杂ZnO体系的介电函数虚部在0.46 eV处均出现新峰, 静态介电函数明显增大, 吸收带边均红移, 并在0.91 eV处出现较强吸收峰, 对产生这一现象的原因给出了定性的讨论.
关键词:
掺杂
ZnO
不同价态
第一性原理 相似文献
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《Surface science》1987,181(3):509-529
We use thermal desorption and metastable quenching spectroscopy to study the properties of CO chemisorbed on Ru(0001); on a Cu monolayer deposited on Ru(0001); and on a Cu film. We find that CO binds more strongly to the Cu monolayer than the Cu film; that the Penning ionization peaks of CO are more prominent on the film; and that addition of CO causes a greater lowering of the work function of the Cu film, than that of the Cu monolayer. We also observe that the 2π1 emission of CO adsorbed on Ru(0001) has a double peak; that the saturation of Ru(0001) with CO seems to lead to CO tilting; and that the Penning spectrum of CO on Cu has two small features which have not been observed for CO adsorbed on other metals. 相似文献
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由于DNA与[Ru(bpy)3]2+(bpy=2,2′-联吡啶)及Cu2+间的静电作用,用自铸膜法在铟锡氧化物(ITO)上制备了橙红色[Ru(bpy)3]2+-DNA-Cu2+复合膜,并应用稳态和暂态荧光光谱、紫外可见光谱、荧光显微镜和扫描电镜对复合膜进行了表征和DNA介导的光诱导电子转移(PET)研究。结果表明,[Ru(bpy)3]2+-DNA-Cu2+复合膜(摩尔比为10∶20∶1)呈现了明显的吸收特征峰(450 nm)和发射峰(λem=595 nm),发光呈单指数衰减,发光寿命为188.6 ns,Cu2+通过DNA介导PET机制猝灭[Ru(bpy)3]2+发光,猝灭常数为6.94×103 L·mol-1,猝灭速率常数为3.80×1010 L·mol-1·s-1;复合膜中Cu2+摩尔比(10倍)的增大使发射峰蓝移了11 nm,吸收和发射强度衰减至消失,Cu2+通过静态猝灭机制削弱[Ru(bpy)3]2+发光。此外,对比于溶液和复合膜中Cu2+对[Ru(bpy)2(tatp)]2+-DNA(tatp=1,4,8,9-四氮三苯)的发光调控,Cu2+仅能因静电作用猝灭复合膜中[Ru(bpy)3]2+的发光。 相似文献