Effect of fine crystalline structure on coercive force of e lectrodeposite d iron films

Iron films 1000 Å thick deposited on sheet copper at pH = 5 at current densities of 0.1–4 A /dm² were investigated. There is a symbatic relationship between H_c and the microstresses.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 14–18, December, 1971.     

Effect of hydrogen on the magnetic characteristics of nanocrystalline iron

This paper reports the results of a complex investigation into the properties of nanocrystalline iron prepared through mechanical dispersion in a hydrogen atmosphere. Magnetic measurements reveal changes in the magnetic characteristics of iron samples obtained for different times of milling (i.e., samples with different grain sizes). The structural transformations responsible for these changes are studied by x-ray diffraction, Mössbauer spectroscopy, and thermogravimetry. It is found that incorporation of hydrogen into the boundary region between single-domain particles of consolidated nanocrystalline iron leads to an increase in the coercive force. Magnetic anisotropy induced by strains is observed. It is established that the strain-induced magnetic anisotropy affects the field dependence of the saturation magnetization of nanocrystalline iron.     

Stark broadening of hydrogen spectral lines with fine structure effects

Formalism and numerical code have been elaborated for calculation of hydrogen line profiles in conditions of plasma in which Stark broadening and fine energy splitting are comparable and it is not possible to neglect either of them. It corresponds to the range of electron densities . Lamb shift and spontaneous emission effects have also been included. Computer simulation method was applied in the calculations. Final results have been compared with experimental and theoretical findings by other authors.Received: 12 September 2003, Published online: 21 October 2003PACS: 32.70.Jz Line shapes, widths, and shifts - 52.20.-j Elementary processes in plasmas     

Effect of hydrogen on the structure of ultradisperse diamond

The paper reports on a study of the effect of annealing in hydrogen on the structural phase transition in clusters of ultradisperse diamond (UDD) obtained by the detonation method. The samples studied were of two types, namely, prepared by the “dry” and “wet” techniques, which differ in the cooling rate of the detonation products and, accordingly, in the structure of the diamond nanocluster shell. It is shown that, irrespective of the type of synthesis, the relative content of the diamond (sp3) phase increases within the anneal temperature range of 450 to 750°C, the increase being more pronounced in the samples prepared by “dry” synthesis. A model accounting for the observed structural transformation processes is discussed. A hypothesis of the possibility of compacting UDD clusters into bulk single crystals is put forward.     

热处理条件对PVA薄膜阻氢性能的影响

 采用XRD测定了PVA薄膜在不同热处理条件下的结晶度，并用自行设计的渗氢系数测量系统研究了在不同热处理条件下的PVA薄膜阻氢性能的变化规律。结果表明，PVA薄膜的热处理温度越高，其结晶度越高，越有利于提高PVA薄膜的阻氢性能，但热处理温度宜选择在180℃以下，以防止PVA薄膜热降解，另一方面，在PVA的玻璃化转变温度以下进行热处理同样能够提高PVA薄膜的阻氢性能，而醇解度较低的PVA薄膜在玻璃化转变温度以下经热处理后的阻氢性能提高的幅度较大。     

热处理条件对PVA薄膜阻氢性能的影响

采用XRD测定了PVA薄膜在不同热处理条件下的结晶度,并用自行设计的渗氢系数测量系统研究了在不同热处理条件下的PVA薄膜阻氢性能的变化规律。结果表明,PVA薄膜的热处理温度越高,其结晶度越高,越有利于提高PVA薄膜的阻氢性能,但热处理温度宜选择在180℃以下,以防止PVA薄膜热降解,另一方面,在PVA的玻璃化转变温度以下进行热处理同样能够提高PVA薄膜的阻氢性能,而醇解度较低的PVA薄膜在玻璃化转变温度以下经热处理后的阻氢性能提高的幅度较大。     

Extended X-Ray absorption fine structure from hydrogen atoms in water

We report the first quantitative measurement of extended x-ray absorption fine structure (EXAFS) from hydrogen atoms. A single oscillation is observed from gaseous water consistent with the location of the covalently bonded hydrogen in H 2O. The experimental phase and amplitude of the oscillation are in excellent agreement with curved wave multiple scattering calculations for isolated water molecules. With this determination of the O-H scattering phase shift we have quantified the covalent hydrogen bond distance (0.95+/-0.03 A) in liquid water, thus demonstrating that hydrogen EXAFS can become a valuable complement to existing structural methods in chemistry and biology.     

Anomalous shifts of hydrogen balmer-α fine structure lines in helium

Resolved H_α fine and hyperfine structure lines are investigated by polarization and double-quantum saturation spectroscopy in a HeH₂ (1%) dc discharge. Anomalous negative density shifts are observed which are correctly predicted by a van der Waals interaction theory. For the pressures below 0.1 Torr a positive shift due to hfs decoupling occurs. Consequences of a comparison with the unresolved H_α line and the alkali D lines are discussed.     

Effect of AlN coating on hydrogen permeability and surface structure of VT6 alloy by vacuum arc ion plating

We study the absorption of hydrogen of metal by the permeability method. With the help of the gas reaction controller(GRC), the absorptive capacity of hydrogen, which is a function of time, temperature and pressure, can be recorded. The effect of the performance of the hydrogen permeability of AlN coating on the titanium alloy surface structure is studied.In the research, the AlN is selected to be added to the titanium alloy sample VT6, and the properties of the titanium alloy are investigated, and the hydrogen absorption rate of the coating is calculated by performing the hydrogen saturation of the test sample. The results show that under 600℃ the AlN film reduces the hydrogen absorption rate of titanium alloy and improves the surface properties of VT6 alloy.     

Effect of hydrogen dimers on the electronic structure of graphene

We investigate the effect of hydrogen dimers on the electronic structure of graphene. Using Greenʼs function and the T-matrix approach, we calculate the local density of states of graphene with single hydrogen dimer, as well as the quasiparticle spectral function of graphene with a finite concentration of randomly distributed hydrogen dimers. Our results show that the effect of dimer adsorption is dramatically different from that of monomer adsorption previously studied, and strongly depends on the configuration of the dimer. The features of the plotted spectral function of graphene are relevant to the band gap opening and the metal–insulator transition.     

Measurement of the fine structure of the n = 4 state of hydrogen

A time-resolved spectroscopy technique has been used to measure the fine structure of the n = 4 state of hydrogen. The excited hydrogen atoms were formed by the use of an electron beam to dissociate molecular hydrogen. The resonance transitions were observed by keeping the radio frequency field fixed and sweeping the magnetic field. Measurements on deuterium were used to study the effects of pressure and motional electric fields. The ²S_1/2 → ²P_1/2 Lamb shift transition , the ²P_3/2 → ²S_1/2 fine structure interval ΔE − L, and the ambient electric field in the measurement volume were determined by using measurements on three separate transitions made at fixed magnetic field. The measurements gave and     

Measurement of neutrino and antineutrino structure functions in hydrogen and iron

The CDHS neutrino detector has been used to measure events originating in a tank of liquid hydrogen and in the iron of the detector. Total cross-sections, differential cross-sections, and structure functions are given for hydrogen and compared with those in iron. The measurements are in agreement with the expectations of the quark parton model. No significant differences indicative of nuclear binding effects in corresponding structure functions of protons and iron are observed. This may be of special interest in the case of the sea structure functions, since large differences are expected in some models.     

Effect of nonuniform mechanical stresses on the domain structure of iron borate

A magnetooptic method is used to study the effect of nonuniform radial mechanical stresses on the domain structure, magnetic susceptibility, and magnetic hysteresis loops of a FeBO₃ single crystal. When a magnetic field is applied in the basal plane of FeBO₃ along the stress vector, a system of tapered domains appears in the crystal during magnetization. These domains exist in a certain temperature-dependent field range H₀ ≤ H ≤ H _c . The appearance of a system of tapered domains is found to substantially affect the technical magnetization of a stressed crystal. The results obtained are discussed within the thermodynamic theory of a domain structure. A theoretical model used is shown to adequately describe the experimental temperature and field dependences of the ratio \({D \mathord{\left/ {\vphantom {D {\sqrt L }}} \right. \kern-\nulldelimiterspace} {\sqrt L }}\) (where D and L are the average width and length of a tapered domain, respectively). The calculated value of D is approximately 1.3 times smaller than the experimentally observed domain width.     

界面氢键对受限水结构和动态特性的影响

应用反应力场分子动力学方法, 模拟了水限制在全羟基化二氧化硅晶体表面间的弛豫过程, 研究了基底表面与水形成的界面氢键, 及其对受限水结构和动态特性行为的影响. 当基底表面硅醇固定时, 靠近基底表面水分子中的氧原子与基底表面的氢原子形成强氢键, 这使得靠近表面水分子中的氧原子比对应的氢原子更靠近基底表面, 从而水分子的偶极矩远离表面. 当基底表面硅醇可动时, 靠近基底表面水分子与基底表面原子形成两种强氢键, 一种是水分子中的氧原子与表面的氢原子形成的强氢键, 数量较少, 另一种是水分子中的氢原子与表面的氧原子形成的强氢键, 数量较多, 这使得靠近表面水分子中的氢原子比对应的氧原子更靠近表面, 从而水分子的偶极矩指向表面. 在相同几何间距下, 当基底表面硅醇可动时, 表面的活动性使得几何限制作用减弱, 导致了受限水分层现象没有固定表面限制下的明显. 此外, 固定表面比可动表面与水形成的界面氢键作用较强, 数量较多, 导致了可动表面限制下水的运动更为剧烈.     

On the fine structure constant

In the framework of a particle model based on a classical minimum action principle a number α′ is derived which is shown to be the analogue of the fine structure constant $\text{α = e}{}^2\text{/}\text{h}\text{?}\text{c}$. To compute α′, a pair of coupled partial differential equations of the second order must be solved. No exact result has been obtained as yet, but it is likely that α′ ? 1. The analogy between α′ and α opens a clear insight into the meaning of the fine structure constant.     

Effect of ion implantation on the fine structure of NiAl-based coatings formed by magnetron deposition

The phase composition and fine structure of intermetallic coatings are investigated by electron microscopy and X-ray analysis. It is shown that intermetallic Ni₃Al is the main phase of the coating for all samples under study. Ion implantation of coatings with aluminum and boron ions leads to changes in the lattice parameter and the parameters of long-range order, internal elastic stress, grain size, and dislocation structure.