Synthesis,Characterization and Oxide Ionic Conductivity of Binary β‐(Bi2O3)1‐x(Lu2O3)x System

In this research, the effects of doping Lu₂O₃ to α‐Bi₂O₃ in the range of 0.01 < x < 0.10 in a series of different mole fractions (1% < n < 10% mole ratios) was studied. Beside, heat treatment was performed by applying a cascade temperature rise in the range of 700‐800 °C for 72 hours and new phases were obtained in the (Bi₂O₃)_1‐x(Lu₂O₃)_x system. After heat treatment for 72 hours at 800 °C; mixtures, containing 2‐8% mole Lu₂O₃, formed a tetragonal phase. As a result of subjecting mixtures, containing 9% and 10% mole Lu₂O₃, to a quenching process at 825 °C, tetragonal phases were obtained. With the help of XRD, the crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. Thermal measurements were made by using a simultaneous DTA/TG system. The total conductivity (σ_T) in the β‐Bi₂O₃ doped with Lu₂O₃ was measured using the four‐probe DC method.     

Amplitude of spatial density fluctuations in glassy propylene carbonate probed by oxygen diffusion

Oxygen translational mobility is very sensitive to structural heterogeneities in molecular glass formers. The heterogeneities manifest themselves as the regions, within which the oxygen jump rates have either the same or similar values. The length of spatial correlation for the oxygen jump rates in glassy propylene carbonate has been determined to be about 1.5 nm [Syutkin et al., J. Chem. Phys. 133 (2010) 074501]. The heterogeneities detected by oxygen diffusion are likely the static density fluctuations associated with a spatially nonuniform distribution of free volume. In the present paper the isothermal dependence of oxygen diffusion coefficient on glass density was measured in propylene carbonate using the technique of phenanthrene phosphorescence quenching by oxygen molecules. Glasses of different densities were produced by annealing samples to the equilibrium state at various temperatures. The amplitude of spatial density fluctuations was calculated assuming that (i) a heterogeneous diffusion is due to density fluctuations, and (ii) the dependence of jump rates on region density is the same as that of oxygen diffusion coefficient on the average glass density. The value for was found to be 0.008 ± 0.003.     

On the Dissociation Energy of AsP Molecule

For the electronic ground state, X¹∑⁺, of AsP molecule, the true potential energy curve is constructed by the method of Rydberg-Klein-Rees. By curve fitting of the modified form of Lippincott's three-parameter empirical potential function, the dissociation energy is estimated to be 4.46±0.15 eV.     

Quantitative O imaging towards oxygen consumption study in tumor bearing mice at 7 T

¹⁷O magnetic resonance imaging (MRI) using a conventional pulse sequence was explored as a method of quantitative imaging towards regional oxygen consumption rate measurement for tumor evaluation in mice. At 7 T, fast imaging with steady state (FISP) was the best among gradient echo, fast spin echo and FISP for the purpose. The distribution of natural abundance H₂¹⁷O in mice was visualized under spatial resolution of 2.5 × 2.5 mm² by FISP in 10 min. The signal intensity by FISP showed a linear relationship with ¹⁷O quantity both in phantom and mice. Following the injection of 5% ¹⁷O enriched saline, ¹⁷O re-distribution was monitored in temporal resolution down to 5 sec with an image quality sufficient to distinguish each organ. The image of labeled water produced from inhaled ¹⁷O₂ gas was also obtained. The present method provides quantitative ¹⁷O images under sufficient temporal and spatial resolution for the evaluation of oxygen consumption rate in each organ. Experiments using various model compounds of R-OH type clarified that the signal contribution of body constituents other than water in the present in vivo¹⁷O FISP image was negligible.     

术中不同浓度氧对病态肥胖阻塞性睡眠呼吸暂停综合征患者术后早期动脉血氧分压的影响

目的观察术中吸入不同浓度氧对病态肥胖患者术后早期动脉血氧分压的影响。方法选择40例ASAⅢ级、因阻塞性睡眠呼吸暂停综合征（OSAS）拟择期行悬雍垂腭咽成形术的病态肥胖（BMI≥40kg／m^2）患者,采用随机数字表法分成80％氧浓度吸入组（H组）和60％氧浓度吸入组（L组）,各20例,测定术前（T0）、气管拔管后10min（T1）、0．5h（T2）、2h（T3）的动脉血气分析指标并作比较。结果两组患者1Io时动脉血气分析中的SaO2、PaO2、PaCO2、pH值的差异均无统计学意义（均P〉0．05）,在T1、T2、T3各时点L组的SaO2、PaO2值明显高于H组（P〈0．05或0．01）,在T、时点,L组的PaCO2明显低于H组（P〈0．05）。结论相较于80％的吸入氧浓度,病态肥胖的OSAS患者术中吸入60％浓度的氧,术后的氧合更好,有利于术后早期呼吸功能的恢复。     

Gas molecule dissociation effect on rf discharge burning in low pressure ammonia

This Letter outlines the experimental study of molecule dissociation effect on rf capacitive discharge burning. We show that for each ammonia pressure value there exists some threshold rf voltage value below which the dissociation degree does not exceed 3%, but at higher rf voltage it grows to 30%. Increasing NH₃ dissociation degree accelerates the discharge current growth against rf voltage. The rf discharge remains in a weak-current α-mode at low as well as at high dissociation degree because all ammonia dissociation products possess ionization potentials exceeding that for NH₃.     

First-principles study of ferromagnetism in Ti-doped ZnO with oxygen vacancy

Using first-principles density functional calculations, we have investigated the electronic structures of Ti-doped ZnO (Ti is in 4+ oxidation state) with and without oxygen vacancy. The ferromagnetic property is identified in the presence of oxygen vacancy despite Ti being nonmagnetic in its natural phase. The ferromagnetism originates from the charge transferring from donor derived-defect band to unoccupied Ti-3d states and the hybridization between Ti-3d and O-2p band near the Fermi level. On increasing the oxygen vacancy concentration, a transition from a long-ranged magnetic order to a short-ranged interaction is found and the oxygen vacancies prefer to distribute non-uniformly in Ti-doped ZnO.     

用可变阶数的代数方法研究双原子体系的完全振动能谱和离解能

不同双原子分子电子态的势能(或振动能谱)的展开性质可能不同,文章将固定阶数的代数方法(AM)改进为可变阶数的代数方法,使得该方法可以研究各种不同性质(不同能量展开阶数)的双原子分子电子态,也可以解决光谱计算中可能出现的"蝴蝶效应"问题。利用阶数可变的AM方法研究了原来固定阶数的AM方法难以给出正确结果的N2-a′1Σu-,Li2+-2 2Σg+,4 He D+-X1Σ+和39 K85 Rb-(2)3Σ+等不同双核体系的完全振动能谱与离解能,不但得到了与实验数据精确相符的理论结果,还正确地预言了许多由于实验条件与技术原因而未能测得的物理数据。研究表明阶数可变的AM方法能够更广泛地用于研究各类双核电子态体系的完全振动能谱和体系离解能。     

The investigation of room temperature ferromagnetism in (1 0 0) oriented BaNb2O6 PLD films on LaAlO3 (1 0 0) substrate

(1 0 0) oriented BaNb₂O₆ films have been successfully grown on LaAlO₃ (1 0 0) substrate at 750 °C or 450 °C in vacuum by pulsed laser deposition. The deposited BaNb₂O₆ PLD films exhibit room-temperature ferromagnetism. Ab initio calculations demonstrate that stoichiometric BaNb₂O₆ and that with barium vacancy are nonmagnetic, while oxygen and niobium vacancy can induce magnetism due to the spin-polarization of Nb s electrons and O p electrons respectively. Moreover, ferromagnetic coupling is energetically more favorable when two Nb/O vacancies are located third-nearest-neighbored. The observed room temperature ferromagnetism in BaNb₂O₆ films should be mainly induced by oxygen vacancies introduced during vacuum deposition, with certain contribution by Nb vacancies.