A Zeolitic rho-type Chiral Metal-organic Framework Based on L-alanine

One new chiral zeolitic rho-type metal-organic framework [Cd(L-ala)2]n(1) has been successfully synthesized based on L-alanine chiral ligand, which demonstrates the feasibility of fabricating MOF that integrates the 4-connected zeotype topology by the employment of L-alanine. To the best of knowledge, it's the first report that metal-organic framework based on amino acid features the chiral zeolitic rho-type structure. Compound 1 was characterized by X-ray powder diffraction, elemental analysis and single-crystal X-ray diffraction. Crystal data: C_6 H_9 CdN_2 O_4, Mr = 285.55, cubic system, space group I432, a = 24.0795(6), V = 13961.9(10) ?~3, Z = 48, Dc = 1.630 Mg/m~3, F(000) = 6672, μ(Mo Kα) = 1.865 mm~(-1), S = 1.058, R = 0.0271 and wR = 0.0312 for 1870 observed reflections with I 2σ(I). The circular dichroism(CD) property of compound 1 was also investigated.     

水杯式光纤Bragg光栅沉降仪的研究

沉降仪是测量路基、桥梁、隧道、边坡等结构物沉降的重要仪器。利用上、下容器相连通结构,研制了一种水杯式光纤Bragg光栅沉降仪。当沉降发生时,在压差的作用下,膜片产生的挠度推动传压杆使等强度悬臂梁的自由端产生同样大小的挠度变化,使粘贴于等强度悬臂梁表面的光纤Bragg光栅发生拉伸,进而导致中心波长发生移位,实验通过检测波长移位可获得沉降量。分析结果显示,光纤Bragg光栅波长移位对沉降量呈现良好的线性关系,沉降仪的灵敏度可达15.4pm/cm,线性度为1.73%FS,迟滞为0.984%FS,重复性误差为3.61%FS。     

隧道二次衬砌监测的非线性回归分析研究

隧道二次衬砌性能劣化是影响隧道健康运营的主要病害,利用光纤通信技术对二次衬砌进行结构安全性分析,是保证隧道工程健康运营的重要手段。以埋入式光纤Bragg光栅应变传感器对田心隧道二次衬砌监测的实际数据为依据,选择最佳的典型函数模型对隧道的监测数据进行非线性回归分析,得出能够反映应变发展变化趋势的回归曲线,预测支护结构(监测点)的应变趋势,判断支护效果,对隧道支护结构当前的和最终的稳定性进行分析,从而实现对隧道结构部的稳定性判断。     

轴对称环状静电模的漂移波湍流参量激发理论研究

本文所论述的轴对称环状静电模是指环形磁约束等离子体(如托卡马克)中环向模数为零的近理想静电流体模,它包含有测地声模和基频率与之较低的声模;也含有所谓的‘近零频带状流’.本文根据冷离子流体模型在圆形磁面构成的准环坐标系中的表示,对涉及以上三种模式的漂移波湍流参量激发理论,在一级环形效应近似下,进行了系统讨论,并证明了带状流的四个新命题.利用对漂移波能谱的参数化描写,注意到由漂移波能谱径向有限宽度所引发的特性,如波能传播量的双Landau奇点,揭示了有限宽度对径向δ谱所得结果的重要修正:如,对近零频带状流和测地声模的参量激发条件带来的严格限制.此外,还讨论了密度带状流在高q条件下被激发的可能性.本文选用合理的物理参数.采用图示方法详细地讨论了有关的数值结果.分析表明,测地声模和近零频带状流的参量激发不可能发生在同一小半径处;如果测地声模被参量激发,也应能观察到密度带状流.     

高频红外碳硫分析仪测定土壤、粘土中的硫

应用高频红外碳硫分析仪测定土壤、粘土中的硫含量,对助熔剂的选择、分析时间、吹氧流量及称样量等分析条件进行优化后对标准样品中的硫含量进行测定,测定结果均在标准值范围内。土壤样品测定结果的相对标准偏差为5.10%(n=8),粘土样品测定结果的相对标准偏差为5.51%(n=8)。该方法对实际样品的测定结果与硫酸钡重量法测定结果相吻合。     

磁固相萃取技术应用于主流烟气中烟草特有N-亚硝胺的测定

合成了甲基丙烯酸改性的Fe3O4磁性纳米颗粒(Fe3O4@Si O2@MAA),建立了磁固相萃取技术与高效液相色谱-串联质谱联用检测主流烟气中烟草特有N-亚硝胺(TSNAs)的方法。该方法通过加入磁性纳米颗粒对萃取液中TSNAs进行富集,洗脱液在HPLC-MS/MS多反应监测模式下进行检测,可满足低焦油和新型烟草制品等低含量TSNAs的检测要求。结果表明:Fe3O4@Si O2@MAA纳米颗粒粒径均一,分散性好,具有超顺磁性,其表面的羧基可吸附溶液中的TSNAs,实现分离富集;该前处理方法操作快速简便,适用于大批量样品分析;4种烟草特有N-亚硝胺的定量下限为0.10~0.48μg/L,加标回收率为88.3%~112.8%,该方法满足复杂烟气背景下痕量TSNAs的检测要求。     

PET共混改性研究

综述了国内外PET共混改性的研究现状 ,并介绍了近年来PET共混研究的新发展     

The intermittent excitation of geodesic acoustic mode by resonant Instanton of electron drift wave envelope in L-mode discharge near tokamak edge

There are two distinct phases in the evolution of drift wave envelope in the presence of zonal flow. A long-lived standing wave phase, which we call the Caviton, and a short-lived traveling wave phase (in radial direction) we call the Instanton. Several abrupt phenomena observed in tokamaks, such as intermittent excitation of geodesic acoustic mode (GAM) shown in this paper, could be attributed to the sudden and fast radial motion of Instanton. The composite drift wave—zonal flow system evolves at the two well-separate scales:the micro-scale and the meso-scale. The eigenmode equation of the model defines the zero-order (micro-scale) variation; it is solved by making use of the two-dimensional (2D) weakly asymmetric ballooning theory (WABT), a theory suitable for modes localized to rational surface like drift waves, and then refined by shifted inverse power method, an iterative finite difference method. The next order is the equation of electron drift wave (EDW) envelope (containing group velocity of EDW) which is modulated by the zonal flow generated by Reynolds stress of EDW. This equation is coupled to the zonal flow equation, and numerically solved in spatiotemporal representation; the results are displayed in self-explanatory graphs. One observes a strong correlation between the Caviton-Instanton transition and the zero-crossing of radial group velocity of EDW. The calculation brings out the defining characteristics of the Instanton:it begins as a linear traveling wave right after the transition. Then, it evolves to a nonlinear stage with increasing frequency all the way to 20 kHz. The modulation to Reynolds stress in zonal flow equation brought in by the nonlinear Instanton will cause resonant excitation to GAM. The intermittency is shown due to the random phase mixing between multiple central rational surfaces in the reaction region.     

两个幂等矩阵的组合的群逆

本文研究了当P与Q是两个复数域上的n阶幂等矩阵且满足PQP=PQ时,组合aP+bQ+cP Q+dQP+eQP Q的群逆问题,利用矩阵的分块及群逆的性质,证明了它是群逆阵,并且给出了其群逆的表达式,其中ab=0,a,b,c,d,e为复数.     

直接测汞仪测定土壤中的总汞

建立了直接测汞仪快速测定土壤中总汞的方法。通过实验对干燥温度、干燥时间、分解温度、分解时间等条件进行了优化,并进行了线性关系、精密度等实验。结果表明,本法线性范围0—500ng,相关系数≥0.9995,检出限为0.0032ng,相对标准偏差为0.56%。方法灵敏度高,简便、快速、准确,适用于对土壤中的总汞的测定。