Radioactivity concentrations in topsoil samples from the Thrace region of Turkey and assessment of radiological hazard

The activity concentrations of gamma emitting radionuclides were measured in surface soil samples from the Thrace region. ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs activities and physico-chemical parameters of the soil samples were determined in samples collected from 73 sampling stations. Radionuclide concentrations measured were compared with those found in the samples from other locations of Turkey and from different countries. The average activity concentrations of ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were found to be 24.71 ± 8.79, 22.30 ± 7.93, 32.09±12.44, 509.00±160.05, 32.74±29.24 Bq kg^?1, respectively. The mean value of the annual effective dose equivalent from the outdoor terrestrial gamma radiation was calculated as 57.2 μ Sv.     

Charge-dependent three-nucleon potential

The charge-dependent three-nucleon potential due to simultaneous photon and pion exchange was derived. The intermediate state of the three-nucleon system was considered to consist of a Δ (1236) resonance. The contribution of this charge-dependent three-nucleon potential to the charge asymmetric energy of ³He−³H is then evaluated using a reasonable trial wave function for a three-nucleon bound system. This contribution turns out to be small but makes the charge asymmetric energy of ³He−³H slightly larger.     

On using lens-assisted hologram interferometry to investigate semiconductor device behaviour

The paper analyses some of the causes that limit the performance of the hologram interferometry method when used for the study of the behaviour of semiconductors devices. Then some results are shown obtained by the authors using a method of lens-assisted microscope hologram interferometry for studying such structures. The method allows detection of defects and, besides, it renders quantitatively the structure local non-uniformities during the normal operation of the semiconductor devices.     

Rayleigh Scattering of 59.5 keV γ-Rays by Mo and Sn

The differential cross sections for coherent scattering of 59.5 keV γ-rays by Mo and Sn were measured using a high-purity germanium detector. The results were compared with predictions of form factor theories and S-matrix calculations.     

Some electrical and structural properties of Cd/CdS/n–Si/Au–Sb sandwich structure

In view of CdS growth is very impotent for technological importance especially solar applications; synthesis of this material remains a topic of great interest for researchers by means of an economically and technically viable method. In the present paper, Cd/CdS/n–Si/Au–Sb sandwich structure has been grown by Successive Ionic Layer Adsorption and Reaction (SILAR) technique. For investigating the structural properties, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) measurements have been performed and it has been seen that films exhibit polycrystalline behavior. The capacitance–voltage (C–V) and conductance/w-voltage (G/w–V) characteristics of Cd/CdS/n–Si/Au–Sb structure have been investigated by considering series resistance and interface states effects. These measurements have been done in the −4 V, 4 V voltage range and in the frequency range of 10 kHz–3 MHz at room temperature. It is seen that, the series resistance (R_s) and interface state density have been strongly depend on frequency. The barrier height, donor concentration, diffusion potential parameters have been determined from the linear C⁻²–V plot. The barrier height values are obtained between 0.495 and 0.796 eV and doping density values have been ranged from 1.455 × 10¹⁴ to 1.999 × 10¹⁴ cm⁻³respectively. The capacitance–frequency (C–f) and conductance/w-frequency (G/w–f) characteristics of Cd/CdS/n–Si/Au–Sb structures have been measured at the various biases 0.00–0.14 V at room temperature. The energy distribution of the interface states (N_ss) and their relaxation time (τ) have been determined from the forward bias capacitance–frequency characteristics. The N_ss and τ values have ranged from 2.01 × 10¹² cm⁻² eV⁻¹and 9.68 × 10⁻⁴ s in (Ec-0.45) eV–2.86 × 10¹³ cm⁻² eV⁻¹ and 3.81 × 10⁻⁴ s in (Ec-0.75) eV, respectively.     

Reinvestigation of the decay scheme of the short-lived isomeric states in112In

The two short-lived isomeric states in¹¹²In have been reinvestigated by means of the¹¹²Cd(d, 2n) and¹⁰⁹Ag (α, n) reactions. Measurements of delayed X- andγ-ray, lifetime and TDPAD spectra have been performed. A 6.32(3) keVγ-ray has been identified in the isomeric decay and anM1 multipolarity has been assigned to it on the basis of the measured internal conversion coefficients:α _L =196(39) andα _tot=231(35). TheE1+M2(δ =+0.24(4)) andE2 multipolarities have been determined for the 263 and 188 keV transitions deexciting the 8^?(T _1/2=2.82(2) μs) and 7⁺ (T _1/2=0.93(2) μs) isomeric states, respectively. A revised isomeric decay scheme is presented.     

高功率多程激光放大系统的优化设计

 利用光束传输模拟程序对高功率多程激光放大系统进行了优化设计, 所用方法和所得结论对高功率激光放大系统的设计有应用意义。     

基于CA和LS-SVM的TE过程多模型建模

针对TE化工过程高度非线性、复杂性的特点,本文提出了一种基于相关分析和最小二乘支持向量机对TE过程进行多模型建模方法,以提高模型性能。首先对TE过程采用相关分析法划分为3个子系统,对每个子系统分别采用基于C-均值聚类的最小二乘支持向量机建模和基于k均值聚类的最小二乘支持向量机多模型建模。实验表明,基于K-均值聚类的多模型建模能简化计算、提高模型精度、并且能更好的预测模型输出。