Optical corrosion meter

In a previous study, a mathematical model relating surface and bulk behaviours of metals in aqueous solution has been developed. The model was established based on principles of holographic interferometry for measuring microsurface dissolution, i.e. mass loss, and on those of electrochemistry for measuring the bulk electronic current, i.e. corrosion current. In the present work, an optical corrosion meter was built based on the above model. The corrosion meter consists of an electrochemical cell in which the sample is immersed in aqueous solution. Furthermore, the corrosion meter has a holographic camera with a thermoplastic film for in situ processing of holograms in order to obtain real-time holographic interferoms of the sample in the electrochemical cell. Results of the present work indicate that optical holography is a very useful technique for measuring the corrosion current density of different alloys in aqueous solutions. As a result, the corrosion current density of aluminium, stainless steel, and low-carbon steel in 1 M KCl, 1 M NaCl, and 1 M NaOH solutions were obtained. A comparison between the corrosion data of samples showed that the corrosion current density of the stainless steel in 1 M NaCl is nearly three-folds higher than that of the aluminium in 1 M KCl and the low-carbon steel in 1 M NaOH.     

Optical absorption by rare-gas atoms in alkali-metal rare-gas alloys

We present results of a Cluster-Bethe Lattice Method calculation of the optical absorption due to rare-gasses in alkali-metal rare-gas alloys. A specific application to the Cs-Xe alloy reveals that the main features of the absorption for the whole concentration range can be understood in terms of a single-quasiparticle model. The effects of short-range order are investigated.     

Electric field gradients in cubic alloys

The theoretical investigations of electric field gradient (EFG) and asymmetry parameter (ν) for cubic dilute alloys are reviewed. The valence and size EFG's and the Sternheimer antishielding factor are discussed in detail. The calculations of EFG and ν for simple and transition metal (TM) dilute alloys of aluminium and copper, TM dilute alloys of vanadium and trinary dilute alloys of noble metals are summarized. It is emphasized that the size EFG is as important as the valence EFG to calculate the total EFG and ν, which are compared with the experimental values. An epilogue for further investigations is added.     

Optical properties of iron alloys with heavy rare-earth elements

Spectral-ellipsometric measurements by the Beatty method were made in the region from 1 eV to 4 eV at temperatures of 100, 293, and 700 K to determine the relation between the distinctive features of the optical absorption spectrum and the principal parameters of the electron energy spectrum in iron alloys with rare-earth elements. The fundamental bands of interband optical absorption of Fe₂-R alloys (R=Gd, Ho, Er) in the region 2.8–3.1 eV are formed by indirect transitions from d-like states, which are genetically bound to 3d–5d electrons of the transition metal and the rare-earth metal, in a state above the Fermi level.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 64–67, December, 1988.We thank our senior research colleague V. A. Domyshev for supplying the samples and carrying out the x-ray structure analysis.     

半微观质子光学势

基于原子核壳模型单体密度矩阵的折叠模型计算光学势的实部,配以唯象光学势虚部,构造半微观光学势.通过拟合质子弹性散射实验数据,得到适用于质量数28~90,能量到200 MeV的半微观质子光学势.该光学势用于质子弹性散射计算分析,在参数大为减少的情况下,计算得到的角分布和分析本领与实验数据的符合程度,总体上好于Koning-Delaroche普适光学势的计算结果.     

Optical dilution and feedback cooling of a gram-scale oscillator to 6.9 mK

We report on the use of a radiation pressure induced restoring force, the optical spring effect, to optically dilute the mechanical damping of a 1 g suspended mirror, which is then cooled by active feedback (cold damping). Optical dilution relaxes the limit on cooling imposed by mechanical losses, allowing the oscillator mode to reach a minimum temperature of 6.9 mK, a factor of approximately 40 000 below the environmental temperature. A further advantage of the optical spring effect is that it can increase the number of oscillations before decoherence by several orders of magnitude. In the present experiment we infer an increase in the dynamical lifetime of the state by a factor of approximately 200.     

The magnetoresistivity of dilute AlMn alloys

A set of accurate measurements of the low temperature magnetoresistivity of dilute AlMn alloys is presented. By using an AlV alloys as a baseline, the resulting negative magnetoresistivity is obtained and compared with theoretical calculations.     

Anisotropic electron-phonon scattering in metals

A previously published general theory for the effects of electron-phonon scattering in metals involves all relevant anisotropies and permits a virtually exact solution of the Boltzmann equation. The electron-phonon interaction is represented by a few Wannier matrix elements that are adjusted to experimental data. Calculations of the electron lifetime and the mass enhancement in copper show good average agreement with the experiments. For reproducing the exact anisotropies further non-diagonal elements have to be considered. The calculated temperature dependence of the Hall effect agrees qualitatively with the observations and reveals the local maximum found for both pure copper and dilute alloys.     

Anisotropic electron-phonon scattering in metals

A previously published general theory for the effects of electron-phonon scattering in metals involves all relevant anisotropies and permits a virtually exact solution of the Boltzmann equation. The electron-phonon interaction is represented by a few Wannier matrix elements that are adjusted to experimental data. Calculations of the electron lifetime and the mass enhancement in copper show good average agreement with the experiments. For reproducing the exact anisotropies further non-diagonal elements have to be considered. The calculated temperature dependence of the Hall effect agrees qualitatively with the observations and reveals the local maximum found for both pure copper and dilute alloys.     

Effect of Laser and Thermal Annealing on Optical and Structural Properties of Amorphous Metal Alloys

The results of ellipsometric measurements of rough and annealed amorphous alloys of 3d-transition metals (Fe, Ni, and Co) with metalloids are presented. Composition of alloys, directions of steady-state bonds between their compounds, and frequencies of the Auger electron transitions are determined by the methods of Auger spectroscopy and from the Raman spectra. Frequencies of metal-metalloid oscillations are determined and strains arising in nanoregions of the crystalline phase are obtained. Different characters of thermal and laser actions on the optical properties of alloys are established, and changes in the optical properties caused by these actions are compared.     

Optical properties and the magnetoimpedance effect in amorphous Co-Ni-B metal alloys

A magnetoimpedance effect is observed in Co_80–xNi_xB20 (x = 4, 6, 8, 10, 12) amorphous metal alloy ribbons when an alternating current at frequencies ranging from 1–3000 kHz is passed through samples in an external magnetic field. Spectra of the permittivity and optical conductivity of the surface of ribbons of these alloys are obtained for incident photon energies of 1.0–5.0 eV. The relationships between the magnitude of the magnetoimpedance effect, and the magnetic properties, electronic structure parameters, and optical characteristics of the amorphous alloy samples are determined.     

不同形态MEH-PPV的构象及其光学特性

通过对在固溶体、稀溶液、薄膜和纳米孔中MEH—PPV的PL和PLE谱的测量分析,研究不同形态下MEH-PPV分子链的构象及其对电子能带和光学性质的影响。在THF稀溶液中,MEH—PPV分子链基本上皆为分立态;在MEH—PPV薄膜中,分子链基本上皆为聚集态;在MEH-PPV／PS固溶体中,MEH—PPV分子链为聚集态和分立态两构象并存,聚集态的比例随MEH-PPV浓度的增加而升高;在多孔氧化铝模板纳米孔中,MEH—PPV分子链形成链束。分立态、聚集态和链束这三种不同构象的分子链具有不同的电子能带结构和光学性质。     

Narrow band gap group III-nitride alloys

Recent results on the properties of narrow gap group III-nitrides and their alloys are reviewed. It is shown that InN with the energy gap of 0.7 eV exhibits classical characteristics of a narrow gap semiconductor with strongly nonparabolic conduction band and an energy dependent electron effective mass. With the new discovery, the direct band gaps of the group III-nitride alloys span an extremely wide energy range from near infrared in InN to deep ultraviolet in AlN offering possibilities for new device applications of these materials. We also discuss properties of dilute group III-N–V alloys in which incorporation of a small amount of nitrogen results in a dramatic band gap reduction. All the unusual properties of the alloys are well described by a band anticrossing model that considers an interaction between localized nitrogen states and the extended states of the conduction band.     

光学胶粘剂

本文介绍了GGJ型光学光敏胶粘剂的主要材料、配比和主要性能。并与其他一些光学胶作了对比,结果表明,该胶可广泛地应用于各种光学仪器,尤其对大批量照相机生产更为适用。该胶毒性小,操作方便,效率高,可提高工效5倍以上。     

Pressure as a parameter in the study of dilute magnetic alloys

A large body of data is reviewed, which illustrates how the high pressure technique can be used to gain information about the magnetic and electronic state of dilute magnetic alloys. Values for the pressure dependence of the elementary effective exchange interaction between a magnetic impurity spin and the conduction electron sea are extracted from the data and tabulated for a number of extremely dilute alloys containing both transition metal and rare earth impurities. Results of experiments on host alloy series employing ‘lattice pressure’ are compared to the present ‘external pressure’ results and critically analysed; it is shown how such a comparison can be used to give information about the extent of the electronic screening around an impurity potential. The effect of pressure on impurity-impurity interactions in spin glasses is also examined; a comparison of the pressure studies on extremely dilute alloys to those on spin glasses allows an estimate of the nature of the interaction mechanisms important in the latter case. Evidence for a pressure-induced spin glass to Kondo transition in LaCe is also presented. It is suggested that the present results fit into a larger picture that magnetism, when present, tends to be weakened when high pressure is applied.     

Optical properties of metallic glasses

Optical reflection spectra of metallic glasses (Pd₈₁Si₁₉ and Pd₈₄Si₁₆) were measured in the spectral range 0.03 to 12 eV and the optical constants were determined by Kramers-Kronig analysis. The experimental reflectivity spectra of glassy Pd₁₈Si₁₉ are similar to the one obtained for Au₈₁Si₁₉ prepared by getter sputtering in argon. However, the energy ranges where intra- and interband optical transitions occur are quite different for the two alloys.     

On the behavior of localized magnetic moments in liquid Cu-Al(Fe) alloys

The magnetic properties of dilute Cu-Al alloys with 5 at.% Fe were measured in the solid and liquid states. The results are compared to the Scalapino formula for the susceptibility of dilute alloys. The transition from the magnetic to the non-magnetic state was observed at 41.5 at.% Al.     

铜铁稀磁合金中铁磁杂质之间相互作用对低温热电势的影响

本文提出在铜铁稀磁合金中高浓度铁磁杂质之间的相互作用对低温热电势的影响巨大, 基于耦合杂质理论, 得出了高浓度铜铁稀磁合金的热电势在4-100 K的温度范围内随温度变化的理论曲线. 理论曲线与铁杂质浓度含量为0.1%(at) Fe, 0.13%(at) Fe和0.15%(at) Fe原子百分比的铜铁合金热电势实验值符合, 为推动低温铜铁稀磁热电偶的应用提供了理论分析基础.     

The ferromagnetic transition temperature of dilute Pd-Co,Pd-Fe and Pd-Mn alloys

Results of resistivity measurements on dilute Pd-Mn alloys with concentrations from 0.15 at .% to 0.7 at .% are discussed. A calculation of the transition temperature of Pd-Co, Pd-Fe and Pd-Mn alloys with concentrations between 0.05 at .% and 3 at .% is presented and compared with the available experimental data.