Acoustical properties of single crystals of mercurous halides

Velocities of propagation of elastic waves along principal crystallographic directions in Hg₂Br₂ and Hg₂J₂ single crystals were measured using the pulse and phase-pulse techniques. The values obtained were used to calculate the components of the elastic tensors c_ik and s_ik, as well as the phase and group velocities of propagation of longitudinal and transverse waves in the (100) and (001) planes, and the angular deviation of acoustic energy flux from the direction of the corresponding wave normal. Knowledge of the anisotropy of the elastic properties of Hg₂X₂ crystals and of their change with the anion (X = Cl, Br, J) leads to deeper understanding of the character of bonds in the crystal lattice and points the way to a better utilization of technical properties of the crystals. — Minimum velocity of propagation of an elastic wave falls in the case of Hg₂J₂ to a value v [100] [11 10] = 0,25 · 10⁵ cm/s, what is the lowest value known among all crystals. Maximum angular deviation of acoustic energy flux — nearly 50° — is exhibited by the quasi-longitudinal wave in Hg₂J₂ crystals. On substituting the Cl⁻ ions with Br⁻ and J⁻ ions, the anisotropy of elastic moduli C₃₃/C₁₁ increases by nearly 80%. Different mechanisms contribute to vectorial dependence of the elastic properties along different crystallographic directions.     

基于遗传LM算法的涂层目标光谱偏振BRDF建模分析

通过比较测量方法测量得到绿漆涂层木板探测目标在400～720 nm的光谱偏振二向反射分布函数值,从获得的户外试验测量数据入手,分析与探测角、波长之间的关系,通过有限探测条件得到的光谱偏振二向反射分布函数值(BRDF)建立光谱偏振BRDF模型,来描述探测目标的偏振二向反射特性。其中利用基于小面元的模型建立光谱偏振BRDF模型,利用遗传算法和Levenberg-Marquardt(LM)算法相结合的优化算法来获得非线性模型参数。仿真实验结果表明采用的遗传LM优化算法具有较好的性能,能较快较准确得到非线性的模型参数。真实实验数据证明了基于小面元模型的正确性,表明光谱偏振二向反射分布函数建模方法结果的可靠性。最后与绿漆涂层铁板目标的模型反演参数进行比较得出：2种不同材质、相同颜色涂层的目标,具有较为接近的折射率,其较小差别可以理解为由涂层的厚度、均匀程度的不同导致,而非不同的材质所引起。     

Enzymatic Synthesis of a Diastereomer of Neoabyssomicin Derivative Using the Diels-Alderase AbyU

Main observation and conclusion The enzyme AbyU catalyses a Diels-Alder (DA) reaction during abyssomicin C biosynthesis.In this study,AbyU is shown to convert t...     

A proposal for preparation of cluster states with linear optics

Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparation ofcluster state. In this paper, we propose the method of generating the large-scale cluster state, which is a platform formeasurement-based quantum computation. In order to achieve more complex quantum circuits, the preparation protocolof N-photon cluster state will be proposed as a generalization of the preparation of four- and five-photon cluster states.Furthermore, our proposal is experimentally feasible.     

Pt/GdFeCo/Pt多层膜的磁性和反常霍尔效应研究

亚铁磁材料因具有反铁磁排列的子晶格磁矩而表现出诸多丰富的物理性质,在磁信息存储和逻辑领域具有广阔的应用前景.本文采用磁控溅射方法在热氧化的硅基片上制备了Pt/GdFeCo(t)/Pt多层膜,系统研究了亚铁磁GdFeCo厚度对多层膜的表面形貌、结构、磁性以及反常霍尔效应(AHE)的影响.结构测试表明薄膜表面粗糙度较小,且GdFeCo层为非晶态;实验中利用GdFeCo层厚度可有效控制Gd元素含量,从而调控GdFeCo趋近反铁磁态特性的磁矩补偿点;通过重金属强自旋轨道耦合效应(SOC)和非晶态亚铁磁薄膜面内压应力,实现了良好垂直各向异性(PMA);进一步阐明了亚铁磁薄膜中磁性和反常霍尔效应的内在产生机制以及磁矩补偿点与温度的内在关系.这些结果为构建新一代低功耗自旋电子器件奠定基础.     

Validated LC‐MS method for simultaneous quantitation of catalpol and harpagide in rat plasma: application to a comparative pharmacokinetic study in normal and diabetic rats after oral administration of Zeng‐Ye‐Decoction

A simple and efficient liquid chromatography‐mass spectrometry (LC‐MS) method was developed and validated for simultaneous quantitation of catalpol and harpagide in normal and diabetic rat plasma. Protein precipitation extraction with acetonitrile was carried out using salidroside as the internal standard (IS). The LC separation was performed on an Elite C₁₈ column (150 × 4.6 mm, 5 µm) with the mobile phase consisting of acetonitrile and water within a runtime of 12.0 min. The analytes were detected without endogenous interference in the selected ion monitoring mode with positive electrospray ionization. Calibration curves offered satisfactory linearity (r > 0.99) at linear range of 0.05–50.0 µg/mL for catalpol and 0.025–5.0 µg/mL for harpagide with the lower limits of quantitation of 0.05 and 0.025 µg/mL, respectively. Intra‐ and inter‐day precisions (RSD) were <9.4%, and accuracy (RE) was in the ?6.6 to 4.9% range. The extraction efficiencies of catalpol, harpagide and IS were all >76.5% and the matrix effects of the analytes ranged from 86.5 to 106.0%. The method was successfully applied to the pharmacokinetic study of catalpol and harpagide after oral administration of Zeng‐Ye‐Decoction to normal and diabetic rats, respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of limonin in dog plasma by liquid chromatography–tandem mass spectrometry and its application to a pharmacokinetic study

A highly sensitive liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 mm ammonium acetate buffer–methanol (26:74, v/v) on a C₁₈ column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 469.4 → 229.3 and m/z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625–100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter‐ and intra‐day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs. Copyright © 2012 John Wiley & Sons, Ltd.     

Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC‐MS/MS assay for pharmacokinetic study

Six esterase inhibitors, namely EDTA·2Na⁺, NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis‐nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mm ) and BNPP (5 mm ), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q‐Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter‐ and intra‐run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions. Copyright © 2012 John Wiley & Sons, Ltd.     

MODEL SIMULATION OF WATER-IN-OIL XANTHAN FERMENTATION

The W/O xanthan fermentation is simulated by integrating the microbial kinetic behaviors and the multiple-phase process characteristics. Model 1 assumes uniform redistribution of cells, substrates and product by frequent droplet breakup and coalescence. Model 2 simulates the system of viscous aqueous phase with minimal droplet breakup and component redistribution. The real fermentation should proceed within the bounds set by the two models. Effects of various parameters are evaluated. The aqueous-phase xanthan concentration (X_n) and volumetric productivity (Q_P) achieved at 200 h are used as the indicators. X_n and Q_P increase with nitrogen-source concentration (S_NO) initially but plateau (Model 1) or decrease slightly (Model 2) at high S_NO. X_n (at 200 h) decreases with increasing aqueous-phase volume fraction (f). Q_P, however, increases with f reflecting its basing on the total dispersion volume. Increasing agitation and aeration result in higher X_n and Q_P. The higher agitation enhances the G/O interfacial oxygen transfer and reduces the droplet size. Increasing aeration improves the G/O interfacial transfer but increases the droplet size. Its net positive effect implies a rate-limiting step at G/O interface. The W/O fermentation can produce far higher X_n (> 200 kg/m3) and Q_P( > 0.8 kg/m3-h) than the conventional fermentation (X_n ～ 50 kg/m3, Q_P ～ 0.5 kg/m3-h).