The Possibility of Wax Formation in Gas Fields： a Case Study

Natural gas production from a gas reservoir(Reservoir A)located in the south of Iran,presents solids deposition during processing because the condensate contains suspended and dissolved solids.Solids deposition occurs not only in the transportation lines from the wells to the separators but also in the various operating units of gas streams and condensate stream.In this study,the multisolid-phase model has been used to predict the wax precipitation from gas and gas condensate fluids.The properties of gas and liquid phases are described using the Soave-Redlich-Kwong(SRK)equation of state.The model is then used to predict the possibility of the wax formation in Reservoir A gas facilities,located at the south of Iran.Solid deposition which occurred in the various streams of that facility confirmed the calculated results.Finally,the wax appearance temperature(WAT),the weight percent of wax formation and the effects of pressure and temperature on the wax formation were also predicted.     

Factors influencing level of hydrogen peroxide in exhaled breath condensate

Hydrogen peroxide (H₂O₂) in exhaled breath condensate (EBC) has been proposed as a marker for oxidative stress in the airways. The aim of the present study was to evaluate the measurement of H₂O₂ in EBC with or without use of a nose clip, and the influence of mouth rinsing, sampling time and storage.An elevated H₂O₂ level was seen during nasal breathing compared to mouth breathing with nose clip (3.4 pmol/s vs. 2.1 pmol/s, p = 0.02). Breathing through the mouth, using a nose clip, was therefore practiced in all experiments. The H₂O₂ levels were increased when mouth rinsing was performed using an acid buffer (1.4 pmol/s vs. 1.9 pmol/s, p = 0.03). 15 min sampling time decreased the H₂O₂ output by almost 50% compared with 2 min sampling time (1.2 vs. 0.6 pmol/s, p = 0.03). When samples were left unattended for 15 min no change in H₂O₂ concentration in the EBC was seen.We found no significant differences in H₂O₂ levels between samples stored for 4 weeks at − 80 °C and samples analysed directly; however, a significant decrease in the levels was seen for samples stored for 4 weeks at − 20 °C.In conclusion, the method of EBC collection and storage plays an important role in reducing variability within and between individuals.     

Electromagnetically Induced Transparency in an Atom-Molecule Bose-Einstein Condensate

We propose a new measurement scheme for the atom-molecule dark state by using electromagnetically induced transparency (EIT) technique. Based on a density-matrix formalism, we calculate the absorption coefficient numerically. The appearance of the EIT dip in the spectra profile gives clear evidence for the creation of the dark state in the atom-molecule Bose-Einstein condensate.     

Quantum Phase Transition in Two Species of Cold Bosonic Atoms

In this letter,the superfluid-Mott-insulator phase transition of two-species cold bosonic atoms in an optical lattices is studied.The Hamiltonian of this model is diagonalized by means of Bogliubov transformations and by the inversion symmetry of the optical lattice,the energy spectrum of this system is obtained.From the energy gap of the excitation spectrum,the quantum phase transition condition is obtained and it is determined by the competition between the interatomic repulsions and the tunnel coupling.It is found that there exists an ordinary fluid phase when taking the zero wave-vector limit.     

原子间相互作用对光场和原子激光压缩性质的影响

对文献中给出的光场与二能级原子玻色-爱因斯坦凝聚体(BEC)相互作用系统的哈密顿量进行分析，表明文献中对原子间相互作用部分的处理有不合理之处，文献中的处理过高估计了原子间相互作用的贡献，从而对该哈密顿量作出了改进.用改进的哈密顿量解析地求解了非旋波近似下光子和原子算符的运动方程，并结合BEC的有关实验条件对哈密顿量中的有关参数作出了估计，研究了光场与原子玻色-爱因斯坦凝聚体相互作用系统中，光场和耦合输出相干原子束的压缩性质.结果表明：光场两正交分量的涨落均随时间按余弦规律周期性地变化，原子激光的两正交分量 关键词： 玻色-爱因斯坦凝聚 压缩相干态 光场的正交压缩 压缩原子激光     

Production and measurement of Bose-Einstein condensate of 87Rb atomic gas

The research platform for Bose-Einstein condensate in ⁸⁷Rb atomic gas, which is composed of a double MOT configuration and a QUIC trap, was reported. The properties of the condensate were measured both in time-of-flight and in tight confinement by the absorption imaging method. The measurements agreed with the criterions of Bose-Einstein condensation phase transition. About 2×10⁵ atoms were pure condensed. Supported by the National Natural Science Foundation of China (Grant No. 10334050) and the National Basic Research Program of China (Grant Nos. 2001CB309307 and 2006CB921202)     

Negative asymptotic topological dimension, a new condensate, and their relation to the quantized Zipf law

We introduce the notion of weight for the asymptotic topological dimension. Planck’s formula for black-body radiation is refined. We introduce the notion of negative asymptotic topological dimension (of hole dimension). The condensate in the hole dimension is applied to the quantized Zipf law for frequency dictionaries (obtained earlier by the author).     

缩酮胺合锌催化二氧化碳和氧化环己烯共聚

二氧化碳作为单体与环氧化物的共聚反应近年来越来越受到重视 .该反应不经过高耗能的还原过程 ,二氧化碳利用率高 ,所得到的产物聚碳酸酯在塑料、弹性体、涂料、胶粘剂、食品包装材料和生物降解材料等方面有广泛的应用 .二氧化碳与氧化环己烯的交替共聚物聚碳酸亚环己酯玻璃化转变温度较高 (Ｔｇ 为 1 2 0℃ ) ,热分解温度达 2 1 0℃以上[1] ,是一种性能优良的高分子材料 .Ｃｈｅｎｇ等于 1 998年首次报道了一种缩酮胺合锌催化剂[2 ] .它是由 β 二酮 (乙酰丙酮 )与 2 ,6 二异丙基苯胺为原料合成的 ,具有西佛碱结构 ,用于二氧化碳与氧化环己…     

Compression of bright bound soliton trains in the Bose-Einstein condensates with exponentially time-dependent atomic scattering length in an expulsive parabolic potential

Three types of two bright bound solitons with increasing coherence are investigated in the Bose-Einstein condensates (BECs) with the exponentially time-dependent interparticle interaction in an expulsive parabolic potential. Two methods are provided with symbolic computation to improve the number of matter density peaks within the given temporal range before the collapse of the solitons under the one-dimensional approximation: (i) enhancing the axial harmonic oscillator frequency; (ii) increasing the initial coherence of the bound solitons. Compression of the three- and four-bright-bound-soliton trains is presented. Estimation of the net binding forces among the bound solitons gives an explanation for the interaction patterns if the coherence of the bound state is limited. Our investigation theoretically reveals the existence of the bright bound solitons in the BECs and analyzes their complex interactions.     

两维有限深势阱中BEC的稳定性分析

研究两维轴对称有限深势阱中BEC的稳定性,利用变分法分别讨论了系统的基态和激发态特性。研究表明系统存在塌缩态、束缚态和扩散态三种状态,并计算出系统状态发生变化的耦合常数的两个临界值,发现势阱的形状与系统的稳定性紧密相关。同时在激发态下进一步讨论了原子间相互作用发生周期性调制的BEC的动力学特性,分析发现有限深势阱中BEC的塌缩可以通过周期性调制散射长度来控制。本文最后讨论了涡旋态下BEC的稳定性,发现系统的塌缩点由于涡旋态的存在而降低。