Reversed Capillary Electrochromatography: Investigation of Peak Symmetry for Eluting Curves of Solutes

Summary A clean method without use of organic solvents has been developed for isolation and high-performance liquid chromatographic (HPLC) determination of oxytetracycline (OTC) and sulphadimidine (SDD) in cow's milk. Isolation is rapid and simple—homogenization with an inorganic acid solution by means of a handy ultrasonic homogenizer, which is easy-to-use and portable, followed by centrifugation. Reversed-phase HPLC was performed on a C₄ column, with 1.25 mmol L⁻¹ succinic acid solution as mobile phase, and identification was by means of a photodiode-array detector. Separation of the analytes was achieved in less than 8 min. Significant linearity was established over the concentration range of 0.1–1.0 μg mL⁻¹ for both target compounds (r>0.99,P<0.01). Average recoveries of OTC and SDD (each spiked at 0.1–1.0 μg mL⁻¹) were ≥88.8, and inter- and intra-assay variability was ≤2.8%. The total time required for analysis of one sample was <20 min. The limits of quantitation of the method (μg mL⁻¹ in milk) were 0.044 for OTC and 0.023 for SDD. No organic solvent was used at any stage of the analysis.     

Laser processing of micro-optical components in quartz

Laser induced backside wet etching combined with the diffractive gray tone phase mask has been used for the fabrication of a micro-lens array with a single lens diameter of 1 mm and a micro-prism in quartz. The micro-lens array was tested as beam homogenizer for high power XeCl excimer laser yielding a clear improvement in the quality of the laser beam.The optimum fluence range for fabrication of micro-lenses by laser induced backside wet etching using 1.4 M pyrene in THF solution and 308 nm irradiation wavelength is 1-1.6 J/cm². The etching mechanisms of LIBWE are based on a combination of pressure and temperature jumps at quartz-liquid interface.     

Shear dependence of viscosity for perfluoropolyether fluids

The shear dependence of the bulk viscosities of two structurally different types of perfluoropolyether fluids was determined by two different techniques. The first involved direct measurement in a high shear Couette viscometer, the second utilized the time-temperature superposition principle to establish master curves from viscosity determinations at low shear rates and temperature; the results are comparable. Both fluids begin to show non-Newtonian behavior at shear rates above 10,000 s^–1.     

Off-site calibration of a two-phase pattern recognition flowmeter

A technique is presented for the measurement of individual phase flowrates in two-phase flow without separation. The technique is based on signal analysis and pattern recognition methodologies to extract, classify and identify stochastic features from turbulent pressure waveforms. Experiments in a horizontal air-water loop have shown that a set of features is uniquely related to the individual phase flowrates. It is shown that the “flowmeter” can be isolated from installation effects by means of a homogenizer.     

直线感应加速器中聚束磁场的数值计算方法

为了准确模拟出直线感应加速器中聚束磁场的值,首先利用单积分法计算出理想情况下的聚束磁场的值,再进一步用磁路分析的方法考虑直线感应加速器的加速腔中匀场环对聚束磁场的影响,然后推导出一组偏离角度与磁场分量相关的公式。将最终得到的聚束磁场分量与直线感应加速器模型结合起来,采用粒子模拟的方法来模拟电子束在加速段中的输运过程,并对结果加以分析。     

Study of plasma technology for silicate refractory melts production

Herein the fundamentally new unit for production of silicate refractory melts with the use of high-concentrated heat fluxes is considered. Mathematical model describing temperature fields in skull layer in the process of the plasma flow interaction with the particles of refractory silicate material has been developed. Typical numerical results of temperature distribution in various sections of the skull layer are presented. Numerical and experimental data have been compared, and their fair agreement is obtained. The work was financially supported by RF President (Grant No. MK 1110.2008.8).     

高速剪切乳化机制备纳米氧化锌及形貌控制

提出了应用高速剪切乳化机制备纳米氧化锌材料的新方法,研究了反应时间、pH值、锌盐浓度、乳化机转速和搅拌方式等实验条件对氧化锌纳米材料形貌的影响.与其它方法相比,用该方法制备纳米氧化锌具有方法简单、条件易控、成本低廉、易于量产、纳米结构几何形状均一等优点.     

D4单体细乳液的稳定性探讨

以八甲基环四硅氧烷（D4）作为模型单体,分别使用高速分散机、超声波仪和高压均质机制备了D4细乳液,使用多重光散射稳定性分析仪（MLS）分析比较了不同方法制备的D4细乳液的稳定性,并通过稳定性的分析,研究了均质压力和乳化剂浓度对单体细乳液的稳定性的影响。结果表明,在同样的乳化剂浓度下采用高压均质机制备的细乳液稳定性最好,能够稳定进行细乳液聚合;随着均质压力(10～110 MPa)增大,D4 细乳液的稳定性先增强后减弱,在90 MPa下制备的细乳液稳定性最好,乳液粒径增长速率仅为0.342 nm/min;随着DBSA浓度(0.0092～0.0460 mol/L)增大,在相同均质条件下（90 MPa 下均质4次）制备的单体细乳液稳定性增强,粒径增长速率都小于0.505 nm/min,具有较好的稳定性。     

辊轧成型工艺制备ZrO2／Al2O3复相陶瓷的性能及结构

采用辊轧工艺，制成了素坯密度较高的氧化锆增韧氧化铝复合陶瓷，并对其性能和结构分别进行了研究。利用多种粒径的粉体混合，多种增韧方式来设计复相陶瓷的显微结构，得到了最佳配比和最佳烧结工艺条件下的ＺｒＯ２／ｎｍＡｌ２Ｏ３／μｍＡｌ２Ｏ３复相陶瓷。此陶瓷在１５５０℃下烧结，得到优良的抗弯强度和断裂韧性。     

高剪切均质机转子系统的临界转速分析

利用Rayleigh法推导了高剪切均质机转子系统的临界转速(一阶固有频率)的解析解;并应用有限元法验证了一阶固有频率(临界转速)和振型,所得结果为此类转子的结构参数优化设计提供了依据.