水的热膨胀的特点演示的探讨

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     

气体的压强与体积的关系的实验设计

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...     

水的表面张力的演示

1.仪器装置取直径为0.5毫米的铜丝做成一个直径为8厘米的圆环,环的直径两端接两根铜丝,铜丝的另一端拧在一起插入软木塞里。再取一只底部尖一点的试管,并且准备一些沙粒和一只盛水缸。 2.操作首先在试管里放些沙粒,用带有     

核物质的物态方程的研究

在相对论σ–ω模型的单圈图近似下,详细推导了核物质的能量密度和压强密度表达式,数值计算了核物质的结合能和压强随核密度的变化,并分别在热力学和流体力学的理论框架下,计算了核物质的压强密度,结果表明这两种方法得到的压强密度相同.     

氧的超导性的发现

氧是生物体和生命过程中的一种重要化学元素,也是大气的重要组成部分．氧的化学式为Ｏ２．从较早的科学研究中已经知道［１］,氧具有很强的顺磁性,随着温度的降低,不但氧的顺磁性增强,而且在一定的低温度下会从气态氧转变为液态氧,在一定的低温和压力条件下,还会从...     

水的热膨胀的演示

利用某些物质溶解时的吸热现象来代替冰——例如按每克分子溶于水时NaNO_3吸热5.03大卡,K_2SO_4吸热6.38大卡,NH_4Cl吸热3.88大卡,只要将其中任何一种溶质溶解于水时,都能使温度降至0℃以下。我们掌握这一点,采用了工业常用的寒剂NH_4NO_3和NaNO_3分别做了实验,实验结果都成功。(一)实验步骤: ①用100c.c.的烧瓶装满纯净的冷水(蒸馏水),将橡皮塞穿两孔,分别插入温度计及内径很小长约15厘米的玻璃管(我们利用内径较大     

光的干涉的教学

光的干涉是关系到光的本性。它是证明光具有波动性质的明显实例,它又是直接关系到光的衍射和偏振的讲授,所以它是物理光学的重要部分。它对于工业生产亦很重要。在工业技术上应用它的亦很多,例如用它来精确地检查滚珠轴承合不合规格,用它来检验量度仪器够不够标准。     

气体的压强跟体积的关系的演示

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     

铝的激发光谱的测量

用１２０ｋｅＶ的Ａｌ＋离子与１０μｇ／ｃｍ２的碳箔相互作用，研究ＡｌⅠ、ＡｌⅡ和ＡｌⅢ的激发光谱，其结果与其它实验进行了比较。     

光的干涉的应用

在科学和技术領域中,人們不断地利用着光的干涉原理解决了許多复杂的实际問題。例如在技术中对于光学表面磨光的检驗,光学部件质量的精密检定,长度微小改变的精密測定(干涉膨胀仪),增透光薄膜的制作,干涉滤光片的制作,軸承滾珠的分类和检驗等等。此外,对于光譜譜线精細結构的研究,物貭折射率的精密测定等也都逐渐轉入利用光的干涉方法来进行。由于光的干涉的应用是如此之广,因而对光干涉应用的各个方面作一全盘介紹显然是很难作到的,故仅就几个重要应用方面作一初步介紹。一、利用光的干涉检定螺旋測微器(千分尺) 在測微器的待量度的平面之間夹入一已知其厚度     

EELS analysis of cation valence states and oxygen vacancies in magnetic oxides

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.     

Chemical effects on Al and Cu Auger electron spectra for the intermetallic compound CuAl2

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.     

Initial stage of oxidation of titanium

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.     

AES analysis of copper growth on MnO

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.     

Surface segregation and surface electronic interactions in PtCu

Photoemission and Auger electron spectroscopy on Pt_0.98Cu_0.02 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.     

脉冲激光沉积的金属原子团簇的电子状态及生长的研究

 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Cu₂p_3/2 X射线光电子谱峰和Cu L₃M_4,5M_4,5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。     

胺化葡萄糖及其铜配合物的光谱特性

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δ_NH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。     

A comparison of the electronic properties of CO adsorbed on a thick copper film,and on a copper monolayer deposited on Ru(0001), as determined by metastable quenching spectroscopy

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.     

不同价态稀土元素Yb掺杂ZnO的电子结构和光学性质

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     

DNA介导复合膜中[Ru(bpy)3]2+与Cu(Ⅱ)间光诱导电子转移

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(λ_em=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。