Luminescent salt

In this contribution, we report on the f-f and d-f luminescence of Ce³⁺, Pr³⁺ and Nd³⁺ in NaCl. The samples were prepared by rapid quenching of a NaCl-melt doped with lanthanides. It is shown that both f-f and d-f emission from lanthanide ions can be observed. Excitation and emission spectra are discussed. In addition to being interesting from a fundamental point of view, it will be argued how the simple alkali halides doped with trivalent lanthanides may be promising as hosts for new scintillator materials.     

Electroluminescence of rock salt

The basic experimental results found in studies of the emission of thin single-crystal layers of rock salt in superhigh electric fields are classified and analyzed. The emission is shown to come from the salt layer and to be due to electronic processes in this dielectric. The basic characteristics of the emission are analyzed, and it is shown to be electroluminescence. The estimated concentration of luminescence centers, data from chemical analysis, and the independence of the spectral characteristics from the “past history” of the samples indicate that the luminescence centers are due to defects in the crystal matrix.     

Thermodynamics of molten salt mixtures

The first two terms of the high energy expansion of the relative density of states for two hard spheres (needed for the computation of the second virial coefficient at high temperature) are obtained directly from the analytic expression for the phase shifts. This is enough to give the classical second virial and the first quantum correction.     

Thermal conductivity of Rochelle salt

The temperature dependence of the anisotropic thermal conductivity of a Rochelle salt single crystal was investigated in different crystallographic directions in the range from −35 to +40°C. No anomalous behaviour was found near the Curie points.     

Steady state investigation on neutronics of a molten salt reactor considering the flow effect of fuel salt

The Molten Salt Reactor (MSR),one of the‘Generation Ⅳ'concepts,is a liquid-fuel reactor,which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt.The study on its neutronice considering the fuel salt flow,which is the base of the thermal-hydraulic calculation and safety analysis,must be done.In this paper,the theoretical model on neutronics under steady condition for a single-liquid-fueled MSR is conducted and calculated by numerical method.The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes,and balance equations for six-group delayed neutron precursors considering the flow effect of fuel salt. The spatial discretization of the above models is based on the finite volume method,and the discretization equations are computed by the source iteration method.The distributions of neutron fluxes and the distributions of the delayed neutron precursors in the core are obtained.The numerical calculated results show that,the fuel salt flow has little effect on the distribution of fast and thermal neutron fluxes and the effective multiplication factor;however,it affects the distribution of the delayed neutron precursors significantly,especially the long-lived one.In addition,it could be found that the delayed neutron precursors influence the nentronics slightly under the steady condition.     

Proton dynamics in Rochelle salt

The investigation of the frequency spectra of Rochelle salt was performed by inelastic incoherent scattering of thermal neutrons using beryllium detector method. The neutron spectra were measured above the upper ferroelectric transition temperature at 307 K and in the polarized phase at 291 K, in the energy range 17–83 meV. Tentative conclusions concerning proton dynamics are drawn from the analysis of the spectra.     

含能离子盐的太赫兹光谱研究

在传统硝基含能材料研究的基础上,进一步探索含能离子盐类物质的太赫兹波谱特性,拓宽太赫兹波技术在安全检测领域的应用研究范围,对新型含能离子盐(5-ATN,BMDATHBT)进行了太赫兹时域光谱和傅里叶变换红外光谱的实验测量,得到样品在0.5～8.0 THz范围内的吸收频谱.基于密度泛函理论,采用Gaussian 03及M...     

Dielectric properties of deuterated ammonium Rochelle salt

The dielectric constant of deuterated ammonium Rochelle salt along the three crystallographic axes as well as the pyroelectric charge density developed on the crystal surface perpendicularly to the b-axis have been measured with a high temperature resolution. The para- to ferroelectric transition at T_c = ?159°C shows a thermal hysteresis of ΔT = 0.15°C. This and the discontinuities in the dielectric constant along all three axes show that the phase transition is of the first-order. No phase intermediate between the para- and the ferroelectric phases could be detected.     

Stability of iodine content in iodized salt

lodization of consumed salts is mandatory in many countries fighting against to iodine deficiency. In salts iodine stability is affected by storage conditions. In this study, stabilization of iodine in salt has been determined by using Isotope Dilution Analysis. Heating, heating with oxidizing agent, incubation by time were the parameters which have been determined. Iodine loss was 41.16% by heating at 200 degrees C up to 24 hours. When the iodized salt heated with oxidized agent iodine loss rose up to 58.46% in 24 hours. Iodine loss mechanism seems similar in both cases. However iodine loss is greater in the presence of H202. After the salt was stored at room temperature with a relative humidity of 30%-45% and in sealed paper bags for three years, 58.5% of iodine content lost in approximately 3.5 years.     

Sizes of solvated ion-clusters in salt solutions

Sizes of solvated ion-clusters were estimated in the approximation of oriented association of polarized solvent molecules around ions and in the approximation of the existence of a self-consistent field in the solution volume. It was shown that the salt concentration in the solution controls the applicability of this or that approximation. The cluster size strongly depends on the concentration at its high values. An increase in the concentration causes an increase in the frequency of the maximum manifestation of the effect of electroinduced selective drift of solvated ions.     

Lead salt quantum well diode lasers

Lead-salt diode lasers are useful for spectroscopic applications in the 2.5–30 μm wavelength range. These devices have previously required cryogenic cooling <100 K) for CW operation. The use of quantum well, large optical cavity structures has improved the operating temperatures to 174 K CW (at 4.39 μm) and to 270 K pulsed (at 3.88 μm). These diodes have a single PbTe quantum well with lattice-matched Pb_1?xEu_xSeyTe_1?y confinement layers grown by molecular beam epitaxy. The emission energy shifts have been calculated using a finite square well with nonparabolicity effects included. Initial work has also been done on multiple quantum well lasers. The maximum operating temperatures were comparable to those of single quantum well lasers, with leakage current and possibly Auger recombination limiting device performance.     

Polarization relaxation in Rochelle salt crystals

The relaxation behavior of the domain structure of a Rochelle salt crystal during its repolarization by a static electric field was studied over a wide temperature range (from ?18 to +24°C). The field and temperature dependences of the relaxation time are found. It is shown that the difference between the activation energies determined far from and near the lower and upper phase transition points is due to the different mechanisms of interaction between domain boundaries and defects.     

Multibubble sonoluminescence in aqueous salt solutions

The sonoluminescence from aqueous solutions containing various salts in the concentration range of 0 to 7 M has been examined using 3.5 ms pulses of 515 kHz ultrasound. In almost all cases the sonoluminescence intensity recorded increased with increasing salt level until a critical concentration (in the range of 1-2 M) was reached. At salt levels above the critical concentration the signal intensity decreased sharply with increasing salt concentration. It is not possible to satisfactorily account for the trends in terms of changes in solution viscosity, rate of bubble coalescence, water vapour pressure, air/water interfacial tension or ionic strength. However, a good correlation of the increase in the signal with the extent of gas solubilisation in the solutions with changing salt concentration was observed. Possible reasons for the signal increase with the addition of salts and the marked decrease at high salt concentrations are discussed.     

Onsager-Manning-Oosawa condensation phenomenon and the effect of salt

Making use of results pertaining to Painlevé III type equations, we revisit the celebrated Onsager-Manning-Oosawa condensation phenomenon for charged stiff linear polymers, in the mean-field approximation with salt. We obtain analytically the associated critical line charge density and show that it is severely affected by finite salt effects, whereas previous results focused on the no salt limit. In addition, we obtain explicit expressions for the condensate thickness and the electric potential. The case of asymmetric electrolytes is also briefly addressed.     

Optimization of salt concentration in PEG-based crystallization solutions

Although polyethylene glycol (PEG) is the most widely used precipitant in protein crystallization, the concentration of co-existing salt in the solution has not been well discussed. To determine the optimum salt concentration range, several kinds of protein were crystallized in a 30% PEG 4000 solution at various NaCl concentrations with various pH levels. It was found that, if crystallization occurred, the lowest effective salt concentration depended on the pH of the protein solution and the pI of the protein molecule; that is, higher salt concentrations were required for crystal growth if the difference between pH and pI was increasing. The linear relationship between the charge density of the protein and the ionic strength of the crystallization solution was further verified. These results suggested that the lowest effective concentration of salt in a crystallization solution can be predicted before performing a crystallization experiment. Our results can be a tip for tuning crystallization conditions by the vapor-diffusion method.     

Effect of salt precursor on laser-assisted copper deposition

Continuous copper structures were precipitated on microscope cover glasses by the laser-induced chemical liquid phase deposition (LCLD) method. The deposition of copper was realized from both CuSO₄- and CuCl₂-based electrolyte solutions. The surface morphology and the chemical composition of the deposits were analyzed with a scanning electron microscope and energy dispersive X-ray spectrometer (EDX). The dependence of the characteristics (width and resistance) of the copper deposits on the laser power, temperature and the salt precursor was examined. The observed strong influence of the solution temperature and the salt precursor on the deposits characteristics was explained by the specific chemical features of the Cu(II)→Cu(0) reduction process. PACS 42.62.-b