Simulation and measurement of 3D shear-driven thin liquid film flow in a duct

Three-dimensional flow behavior of thin liquid film that is shear-driven by turbulent air flow in a duct is measured and simulated. Its film thickness and width are reported as a function of air velocity, liquid flow rate, surface tension coefficient, and wall contact angle. The numerical component of this study is aimed at exploring and assessing the suitability of utilizing the FLUENT-CFD code and its existing components, i.e. Volume of Fluid model (VOF) along with selected turbulence model, for simulating the behavior of 3D shear-driven liquid film flow, through a comparison with measured results. The thickness and width of the shear-driven liquid film are measured using an interferometric technique that makes use of the phase shift between the reflections of incident light from the top and bottom surfaces of the thin liquid film. Such measurements are quite challenging due to the dynamic interfacial instabilities that develop in this flow. The results reveal that higher air flow velocity decreases the liquid film thickness but increases its width, while higher liquid flow rate increases both its thickness and width. Simulated results provide good estimates of the measured values, and reveal the need for considering a dynamic rather than a static wall contact angle in the model for improving the comparison with measured values.     

CeO_2缓冲层热处理对Tl-2212薄膜超导特性的影响

本文采用原子力显微镜(AFM)和XRD研究了生长在蓝宝石(11-02)基片上的CeO_2缓冲层在不同的退火温度和退火时间下表面形貌和相结构的变化,以及对Tl-2212薄膜超导特性的影响.AFM和XRD研究表明,CeO_2薄膜在流动氧环境中退火,表面形貌发生显著的变化;CeO_2薄膜在最佳条件下退火后,可获得原子级光滑表面,结晶质量明显提高.实验结果表明,缓冲层的结晶质量和表面粗糙度与Tl-2212薄膜的超导特性密切相关.在经过最佳条件退火后的CeO_2缓冲层上制备了厚度为500 nm无裂纹的Tl-2212超导薄膜,其临界转变温度(T_c)达到107 K,液氮温度下临界电流密度(J_c)为3.9 MA/cm~2(77 K,0 T),微波表面电阻(R_s)约为281 μΩ(77 K,10 GHz).     

Pt/Hg3In2Te6接触的温度特性研究

运用直流平面磁控溅射技术在Hg3In2Te6单晶表面制备Pt金属电极,形成Pt/Hg3In2Te6接触,采用I-V测试仪在120~260 K温度范围内对其I-V特性进行测量.根据热电子发射模型,计算得到了Pt/Hg3In2Te6的肖特基势垒高度.结果表明:Pt/Hg3In2Te6形成具有整流特性的肖特基接触,肖特基势垒高度为0.46 eV.在120~260 K温度范围内,理想因子随温度增大逐渐从2.93减小至1.42.将Hg3In2Te6单晶制成红外探测器,发现了响应光谱在波长1.55 μm处峰值达到最大,在室温下峰值探测率D* 达到了1011 cm·Hz1/2·W-1.     

八元瓜环与氧氟沙星、氟罗沙星、加替沙星及司帕沙星相互作用的光谱法研究

用荧光光谱和紫外吸收光谱研究了八元瓜环与氧氟沙星、氟罗沙星、加替沙星及司帕沙星的相互作用体系的性质,考察了溶液酸度对作用体系的影响。在pH小于8.0的范围内,八元瓜环分别与氧氟沙星、氟罗沙星、加替沙星形成1∶1、与司帕沙星形成2∶1的稳定的主客体化合物;测定了不同pH时主客体相互作用的稳定常数均在103～104 L·mol-1(司帕沙星体系为1011 L2·mol-2)范围;同时测定了各作用体系的荧光发射和紫外吸收分析性能参数,药物客体的浓度线性范围达2～3个数量级,检测限为10-9～10-8 mol·L-1。     

一种蛋白同化激素新药的成分分析及其尿样监控

利用红外光谱、核磁共振氢谱、紫外光谱以及质谱等表征手段对一种新型蛋白同化激素(AAS)口服药物的主成分进行了研究和鉴定,推定主成分为甲基-1-睾酮(methyl-1-testosterone, M1T, 17β-hydroxy-17α-methyl-5α-androst-1-en-3-one)。在此基础上,建立了M1T的气相色谱-质谱联用检测方法。方法的检出限（信噪比（S/N)为3)为2 ng/mL,定量限（S/N=10）为10 ng/mL;7次平行测定前处理后的加内标尿样的相对标准偏差为9.8%。用该方法测定了该药物在尿样中的排泄曲线。该方法的建立为AAS新药的发现、检测和监控做了很有意义的基础研究工作。     

基于一种新型有机聚合物整体柱的毛细管电色谱技术用于利尿剂的分离与检测

采用自制的新型有机聚1-十六碳烯-三羟甲基丙烷三甲基丙烯酸酯［poly(1-hexadecene-co-TMPTMA)］整体柱,建立了一种同时分离检测6种利尿剂(氯噻酮、氢氯噻嗪、美托拉宗、吲哒帕胺、坎利酮和螺内酯)的毛细管电色谱(CEC)新方法,并成功应用于志愿者实际尿样的分析测定。在最佳实验条件下,6种利尿剂包含2种中性物质(坎利酮和螺内酯)和2种同分异构体(美托拉宗和吲哒帕胺)在11.0 min内得到基线分离,柱效分别达到218000、176000、143000、121000、108000、103000 塔板/m。6种利尿剂在1.15～86.0 μg/mL范围内呈良好的线性关系,相关系数R2 ≥0.990 8,检出限(LOD)在0.35～0.65 μg/mL范围内,回收率为81.9%~105%,相对标准偏差(RSD)小于4.7%。结果表明,实验所建立的基于poly(1-hexadecene-co-TMPTMA)整体柱的CEC方法,具有良好的重复性和稳定性,能够实现对多种利尿剂的同时分离检测。该方法已成功应用于来自志愿者实际尿样的分析,该方法可以用于利尿剂类药物的初筛。     

基于N-十二酰基-l-脯氨酸为载体的对映异构PVC膜选择性电极的研制

合成了手性物质N-十二酰基-l-脯氨酸(N-DDO-l-Pro)(脯氨酸, Pro), 作为PVC膜电极的载体, 在PVC膜表面与被测试液中Cu(II)与脯氨酸形成的配合物[Cu(II)(l-Pro)₂]或[Cu(II)(d-Pro)₂]进行配体交换, 形成[(l-Pro)Cu(II) (N-DDO-l-Pro)]或[(d-Pro)Cu(II)(N-DDO-l-Pro)]配合物. 由于生成的配合物热力学稳定性不同, 电极能优先响应l-Pro, 线性范围10^－4～10^―1 mol•L^－1, 斜率57 mV•dec^－1, 检测限3.89×10^－5 mol•L^－1. 电极能够对脯氨酸进行手性检测, 其对映选择性系数lg为－3.19.     

功能梯度材料瞬态热传导问题的降维精细积分法

针对功能梯度材料(FGMs)的二维瞬态热传导问题,提出了一种有效的降维精细积分法。通过空间坐标的分步离散,将原二维问题的精细积分转化为一系列一维问题的精细积分,解决了直接精细积分算法所面临的传递矩阵 规模过大的问题,从而大幅度降低了计算量和存储量。算例表明了本文方法的有效性。     

Dispersion characteristics of two-dimensional unmagnetized dielectric plasma photonic crystal

This paper studies dispersion characteristics of the transverse magnetic (TM) mode for two-dimensional unmagnetized dielectric plasma photonic crystal by a modified plane wave method. First, the cutoff behaviour is made clear by using the Maxwell--Garnett effective medium theory, and the influences of dielectric filling factor and dielectric constant on effective plasma frequency are analysed. Moreover, the occurence of large gaps in dielectric plasma photonic crystal is demonstrated by comparing the skin depth with the lattice constant, and the influence of plasma frequency on the first three gaps is also studied. Finally, by using the particle-in-cell simulation method, a transmission curve in the \Gamma -X direction is obtained in dielectric plasma photonic crystal, which is in accordance with the dispersion curves calculated by the modified plane wave method, and the large gap between the transmission points of 27~GHz and 47~GHz is explained by comparing the electric field patterns in particle-in-cell simulation.     

Integration of B-spline geometry and ANCF finite element analysis

The goal of this investigation is to introduce a new computer procedure for the integration of B-spline geometry and the absolute nodal coordinate formulation (ANCF) finite element analysis. The procedure is based on developing a linear transformation that can be used to transform systematically the B-spline representation to an ANCF finite element mesh preserving the same geometry and the same degree of continuity. Such a linear transformation that relates the B-spline control points and the finite element position and gradient coordinates will facilitate the integration of computer aided design and analysis (ICADA). While ANCF finite elements automatically ensure the continuity of the position and gradient vectors at the nodal points, the B-spline representation allows for imposing a higher degree of continuity by decreasing the knot multiplicity. As shown in this investigation, a higher degree of continuity can be systematically achieved using ANCF finite elements by imposing linear algebraic constraint equations that can be used to eliminate nodal variables. The analysis presented in this study shows that continuity of the curvature vector and its derivative which corresponds in the cubic B-spline representation to zero knot multiplicity can be systematically achieved using ANCF finite elements. In this special case, as the knot multiplicity reduces to zero, the recurrence B-spline formula causes two segments to automatically blend together forming one cubic segment defined on a larger domain. Similarly in this special case, the algebraic constraint equations required for the C ³ continuity convert two ANCF cubic finite elements to one finite element, demonstrating the strong relationship between the B-spline representation and the ANCF finite element representation. For the same order of interpolation, higher degree of continuity at the finite element interface can lead to a coarser mesh and to a lower dimensional model. Using the B-spline/ANCF finite element transformation developed in this paper, the equations of motion of a finite element mesh that represents exactly the B-spline geometry can be developed. Because of the linearity of the transformation developed in this investigation, all the ANCF finite element desirable features are preserved; including the constant mass matrix that can be used to develop an optimum sparse matrix structure of the nonlinear multibody system dynamic equations.