Comparison and control of the robustness between quantum entanglement and quantum correlation in an open quantum system

We investigate the influence of environmental decoherence on the dynamics of a coupled qubit system and quantum correlation.We analyse the relationship between concurrence and the degree of initial entanglement or the purity of initial quantum state,and also their relationship with quantum discord.The results show that the decrease of the purity of an initial quantum state can induce the attenuation of concurrence or quantum discord,but the attenuation of quantum discord is obviously slower than the concurrence’s,correspondingly the survival time of quantum discord is longer.Further investigation reveals that the robustness of quantum discord and concurrence relies on the entanglement degree of the initial quantum state.The higher the degree of entanglement,the more robust the quantum discord is than concurrence.And the reverse is equally true.Birth and death happen to quantum discord periodically and a newborn quantum discord comes into being under a certain condition,so does the concurrence.     

Comparative study of adsorption characteristics of Cs on the GaN(0001) and GaN(000) surfaces

The adsorption characteristics of Cs on GaN(0001) and GaN(000) surfaces with a coverage from 1/4 to 1 monolayer have been investigated using the density functional theory with a plane-wave ultrasoft pseudopotential method based on first-principles calculations.The results show that the most stable position of the Cs adatom on the GaN(0001) surface is at the N-bridge site for 1/4 monolayer coverage.As the coverage of Cs atoms at the N-bridge site is increased,the adsorption energy reduces.As the Cs atoms achieve saturation,the adsorption is no longer stable when the coverage is 3/4 monolayer.The work function achieves its minimum value when the Cs adatom coverage is 2/4 monolayer,and then rises with Cs atomic coverage.The most stable position of Cs adatoms on the GaN(000) surface is at H3 site for 1/4 monolayer coverage.As the Cs atomic coverage at H3 site is increased,the adsorption energy reduces,and the adsorption is still stable when the Cs adatom coverage is 1 monolayer.The work function reduces persistently,and does not rise with the increase of Cs coverage.     

Two localized CO₂ laser treatment methods for mitigation of UV damage growth in fused silica

Two methods:high-power,short-time,single-shot irradiation(Method A) and low-power,long-time,multi-shot irradiation(Method B) are investigated to mitigate the UV damage growth in fused silica by using a 10.6-μm CO2 laser.To verify the mitigation effect of the two methods,the laser induced damage thresholds(LIDTs) of the mitigated sites are tested with a 355-nm,6.4-ns Nd:YAG laser,and the light modulation of the mitigation sites are tested with a 351-nm continuous Nd:YLF laser.The mitigated damaged sites treated with the two methods have almost the same LIDTs,which can recover to the level of pristine material.Compared with Method A,Method B produces mitigated sites with low crater depth and weak light modulation.In addition,there is no raised rim or re-deposited debris formed around the crater edge for Method B.Theoretical calculation is utilized to evaluate the central temperature of the CO2 laser beam irradiated zone and the radius of the crater.It is indicated that the calculated results are consistent with the experimental results.     

对磺酰胺基苯基重氮氨基偶氮苯的合成及其与镉显色反应的研究

报道了新显色剂对磺酰胺基苯基重氮氨基偶氮苯的合成及其与镉的显色反应。在非离子表面剂活性剂 OP存在下 ,于 p H11.2 6的 NH4Cl- NH3 · H2 O缓冲溶液中 ,新试剂与镉生成 3∶ 1的稳定络合物 ,最大吸收波长在 5 10 nm处 ,表观摩尔吸光系数 ε=1.2 3× 10 5L·mol-1·cm-1。镉量在 0— 10 .6 7μg/ 2 5 m L范围内遵守比耳定律。本法用于测定工业废水中微量镉 ,结果令人满意     

Urea sensors based on PVC membrane pH electrode

Several procedures of urease immobilization on the surface of the polymeric membrane pH electrode with tri-n-dodecylamine as a neutral carrier were compared. The best results were obtained for the urea sensor with covalently bound urease. The sensor characteristics including the effect of buffer, pH and concentration and the effect of stirring rate are presented. These effects are in good agreement with theoretical expectations.     

Dissociation constants of thymolphthalexone

For the dissociation constants of thymolphthalexone the following values have been found: pK(3) = 7.03 +/- 0.02, pK(4) = 8.05 +/- 0.09 (by potentiometric titration), pK(5) = 10.83 +/- 0.10, pK(6) = 12.99 +/- 0.11 (by spectrophotometry). They were determined at I = 0.4 and at 25 degrees.     

Properties of 4-amino-4'-methyldiphenylamine as a redox indicator

The properties of 4-amino-4'-methyldiphenylamine as a redox indicator have been studied. The compound acts as a reversible, one-colour indicator, the oxidized form being red-violet, with molar absorptivity 6 x 10(3) l.mole(-1).cm(-1) at lambda(max) = 510 nm. The formal potential is described by the equation E = 0.735-0.059 pH. The two dissociation constants are pK(1) = -0.08 +/- 0.09 and pK(2) = 5.09 +/- 0.02. The relative error of titration of iron(II) with vanadium(V) is not larger than 0.2%.     

Optical Properties of Amorphous Films of an a-Si<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Ge<Subscript>x</Subscript>:H Solid Solution with Different Concentrations of Hydrogen

The IR absorption spectra of hydrogenated amorphous films of an a-Si_0.60Ge_0.40:H solid solution that were obtained by plasmachemical deposition at different partial pressures of hydrogen have been investigated. The oscillator strengths Γ that depend substantially on have been determined. It is shown that hydrogen is contained in the films mainly in the GeH and SiH forms. Using integral absorptions I_w, the concentrations of hydrogen were determined. The highest value of is observed at Γ = 0.51, P = 4.16, N_H = 9.7·10²¹ cm⁻³, and C^H = 23.7 at.%. It has been established that the oscillator strengths depend on the hydrogen concentration: they decrease on hydrogen effusion and increase with the hydrogen concentration. It is shown that the hydrogen concentration in the films of the a-Si_0.60Ge_0.40:H solid solution can be controlled by changing its pressure. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 371–376, May–June, 2005.     

Coulometric titration in the study of metal ion-ligand equilibria

The coulometric titration technique is applied to evaluation of stability constants of metal complexes with ligands which have protolytic properties. The validity of the procedure was checked by studying several well-known systems. The proposed method can be used with success when metal ions are not reduced at the working cathode. Constants for calcium and magnesium complexes with components of some biologically important buffers, so-called Good buffers, were evaluated under experimental conditions (ionic strength of 0.16M, 37 degrees ) used in clinical analysis.     

Investigating mesoscopic circuits with entangled state representations

By employing the continuous parameter entangled state representations, we investigate the energy level and the wave function for a capacitively and mutual-inductively coupled LC mesoscopic circuit. It is found that investigating the meso- scopic circuit in such representations can bring us the following conveniences. Firstly, the dynamical equation is naturally transformed into a single-variable differential equation. Secondly, the center-of-mass kinetic energy is included in the energy level of the system. Thus it is instructive to introduce the entangled state representation into the investigation of mesoscopic circuits.