共查询到19条相似文献,搜索用时 62 毫秒
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穆斯堡尔谱学的发展,希望能获得更理想的穆斯堡尔源。本文报道了为穆斯堡尔实验制作这种源的程序:首先生产出纯度高的~(57)Co,配成电镀液,待~(57)Co沉积在源基体上后,经热扩散后测试所作源的各个参量。 相似文献
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~(119m)Sn穆斯堡尔诺学从六十年代末期以来有了很大发展,它已深入到各个学科领域,在化学方面的应用尤为突出。1976年,我们首次利用~(119m)Sn穆斯堡尔谱研究新型高级脱氢Pt-Sn体系催化剂和性能优良的稀土钻永磁合金。本文扼要介绍了~(119m)Sn穆氏谱基本原理,重点讨论了应用于上述两个领域的研究成果和前景。 在新型铂-锡脱氢催化剂研究中,~(119m)Sn穆斯堡尔谱的研究不仅表明,铂存在促进了锡还原,(SnO_2)氧化 Pt→PtOx (sn)还原,而且在一定程度上证明非络合浸渍法催化剂中铂与锡的相互作用不及络合法中的强, 相似文献
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穆斯堡尔同质异能移的基本物理概念已经被知道很长时间了。然而具体的理论表示却一直是人们关心的课题。由于这种超精细相互作用始终涉及核因子和电子因子(或称固体因子)的乘积,给解释这些数据带来困难。近年来,随着大型计算机的使用,人们可以较好地计算核内电子浓度,再利用测量的同质异能移,找出定标常量α来代替核因子,从而大大推动了这方面的研究工作。但是目前关于电子浓度的理论计算,大部分是以自由原子模型为基础的,而当原子被携带在一起形成固体时,这种自由原子是根本不存在的。 相似文献
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从回旋加速器上照过的镍靶中分离~(57)Co 总被引:1,自引:0,他引:1
制作穆斯堡尔源~(57)Co的纯度要求很高,杂质含量应小于0.12μg/mCi~(57)Co。稳定性钴含量的增加,使源的线宽加宽甚至发生劈裂现象。降低稳定性钴含量的办法,即可在照射前对靶材料进行纯化,也可在照射后利用核衰变特性和放化分离法相结合,进行钴的同位素分离。本文报导了采用α-粒子轰击镍试制~(57)Co的实验结果。 1.照射靶的制作 天然镍有五种同位素,其中~(58)Ni的丰度最高(67.88%)。α轰击天然镍除得到~(57)Co外,还可生成十多种其 相似文献
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1 Introduction It is well known that DLC (diamond-like carbon)prepared by physical vapor deposition, plasma en-hanced chemical vapor deposition (PECVD) and otherplasma processing is an amorphous carbon materialcontaining sp2 and sp3 bonded carbon atoms. DLCfilm possesses some interesting properties, such ashigh hardness and Young's modulus, chemical inert-ness and low friction coefficient. The property andstructure of DLC film can be modified by addingsome metals. Ion implantation… 相似文献
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G. Mattei C. de Julin Fernndez G. Battaglin C. Maurizio P. Mazzoldi C. Scian 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2006,250(1-2):225-228
Sequential ion implantation of Au and Fe ions has been performed in silica. Despite the fact that the two species are not miscible in the bulk, structural characterizations show that the nanoparticles produced are a Au–Fe alloy. The crystalline structure of the nanoparticles is fcc with a lattice parameter of 0.395 nm. The nanocomposite is ferromagnetic at 3 K, with a magnetic moment per Fe atom equal to 1.4μB and it shows a hysteresis loop with a coercive field of 24 mTorr. Due to alloying, the optical absorption spectrum does not exhibit the typical surface plasmon resonance of gold nanoparticles. The sample exhibits a change of its optical and structural properties when is annealed at 600 °C. 相似文献
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A. Tóth M. VeresK. Kereszturi M. MohaiI. Bertóti J. Szépvölgyi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(16):1855-1858
The surface modification of poly(ethylene terephthalate) (PET) by helium plasma based ion implantation (He PBII) was studied. The effect of the main process parameters (acceleration voltage, fluence and fluence rate) on the alterations of the surface chemical composition and structure were investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.According to SRIM calculations, at ion energies above 2 keV the stopping power of PET for He+ ions is dominated by the electronic component and the contribution of the nuclear component is relatively small. Degradation of the ester group and carbonisation were observed by XPS due to elimination of O-rich fragments. The total C-content of the modified layer increased with the increase of fluence rate and acceleration voltage of particles, enabling the purposeful alteration of the surface composition. A strong broadening was detected in the Raman spectrum between 1000 and 1700 cm−1, testifying to the intense formation of amorphous carbon. The area ratio of the D (∼1410 cm−1) to G (∼1570 cm−1) band increased with the increase of particle fluence and the increase of acceleration voltage, offering the possibility of tailoring the chemical structure of the amorphous carbon layer created by the He PBII treatment. 相似文献
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质谱检测用同位素15N标记样品的处理方法 总被引:1,自引:0,他引:1
采用质谱法分析稳定同位素15N标记化合物的15N丰度,进样形式为氮气时,具有记忆效应小、不发生同位素分馏的优点,因此,待测样品处理方法非常关键。选用具有代表性的15N无机标记化合物和15N有机标记化合物进行了次溴酸盐氧化还原法、半微量的消化 氧化还原联用法和微量的高温燃烧法等样品处理方法的条件试验,消除了样品转化处理过程中的同位素分馏效应和记忆效应的影响,样品的检测结果准确度和精确度令人满意,误差小于±0.05%。研究得到了具有可行性的样品转化条件和操作方法。采用数理统计方法对得到的质谱检测数据进行检验,获得了满意的结果。 相似文献
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M. Ueda A.R. Silva Jr.Carina B. Mello G. Silva H. ReutherV.S. Oliveira 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(24):3246-3250
In this work, we investigated the effects of the contaminants present in the vacuum chamber of the PI3 system, in particular, the residual oxygen, which results in the formation of the oxide compounds on the surface and hence is responsible for the high implantation energies required to achieve reasonably thick treated layers. We used a mass spectrometer (RGA) with a quadruple filter to verify the composition of the residual vacuum and pressure of the elements present in the chamber. Initially we found a high proportion of residual oxygen in a vacuum with a pressure of 1 × 10−3 Pa. Minimizing the residual oxygen percentage in about 80%, by efficient cleaning of the chamber walls and by improving the gas feeding process, we mitigated the formation of oxides during the PI3 process. Therefore we achieved a highly efficient PI3 processing obtaining implanted layers reaching about 50 nm, even in cases such as an aluminum alloy, where is very difficult to nitrogen implant at low energies. We performed nitrogen PI3 treatment of SS304 and Al7075 using pulses of only 3 kV and 15 × 10−6 s at 1 kHz with an operating pressure of 1 Pa. 相似文献