电感耦合等离子体原子发射光谱法测定水中7种微量元素

利用电感耦合等离子体原子发射光谱法测定了矿泉水及饮用水中的铝、铬、锰、汞、镉、铅、镁等7种元素的含量。结果表明:标准曲线的线性关系良好,检出限为0.000 9⁰.075 9μg/mL,精密度为0.530.075 9μg/mL,精密度为0.53².42,加标回收率在101.2%2.42,加标回收率在101.2%¹06.5%之间。     

柴胡疏肝散复方前后微量元素溶出量变化分析

采用硝酸∶高氯酸为4∶1的混酸消解,用火焰原子吸收法柴胡疏肝散复方前后提取液中的三种人体必需的微量元素Cu、Mn、Fe的溶出量。结果表明,单煎液中铜、铁的含量高于合煎液中铜、铁的含量,而单煎液中锰的含量低于合煎液中锰的含量。     

ICP-OES测定钛铁矿中11种杂质元素

研究建立了用HNO3-HF-HClO4-HCl分解钛铁矿试样,利用电感耦合等离子体发射光谱仪(ICP-OES)同时测定钛铁矿中V、Cu、Mn、Pb等11种杂质元素的测定方法。确定了仪器测定最佳工作条件及分析谱线,采用Y内标元素消除钛、铁基体效应。方法的线性相关系数>0.999,相对标准偏差为0.60%～3.73%,加标回收率为94%～108%。结果表明:本法精密度和准确度较好,方法快速、简便。     

DRYING KINETICS OF APRICOTS

The kinetics of apricot dehydration was examined using a factorial experimental design in order to evalute the effect of air temperature, air velocity and pretreatment of the sample on the drying time and the transport coefficients of apricots. A finite element method was used to solve the differential equations describing the transfer of moisture in the irregular shape of the apricot. The two transport coefficients of the system were estimated using non-linear regression analysis. It was found that the moisture transfer is entirely controlled by the external resistance to mass transfer for the air velocities examined. A new method is proposed for the evaluation of the relative significance of the external and the internal mass transfer during, which should repiace the well known Biot number criterion.     

稀土元素对油脂加氢催化剂性能的影响

采用共沉淀法制备镍基油脂加氢催化剂,制备过程中加入稀土元素镧、铈的硝酸盐对拟薄水铝石进行改性。采用棕榈油加氢实验评价催化剂的活性,通过物理吸附、扫描电镜、X射线衍射和激光粒度等对催化剂进行表征。结果表明,该催化剂的活性和物理性能随镧、铈配比的不同而变化。镧铈质量比为1∶4时,催化剂的加氢活性最高。加入稀土元素后该催化剂的比表面积略有提高,孔容略有降低;催化剂粒度减小;活性组分分散度有所提高;晶粒大小和晶形均未发生明显变化。     

Numerical and experimental analyses of a fracture mechanics test for adhesively bonded joints

The use of a fracture mechanics test to evaluate the joint strength through the determination of the strain energy release rate G is nowadays well established. The joint strength for fluorinated polymer (PVDF) sheets bonded with an epoxy adhesive was studied using a double cantilever beam (DCB). In order to obtain small-scale yielding, the adhesive joint of the polymer specimens was strengthened by steel sheets. Pre-cracks were initiated at the center of the bond thickness separating the two PVDF surfaces, with nominal lengths ranging from 5 to 27.5 mm. We did not measure the evolution of the crack length, which is generally very difficult to obtain with good precision. The measurement of the load-point displacement was used instead. The opening load versus this load-point displacement was recorded. The slope of the first part of this curve gives the value of the initial stiffness of the joint specimen. The stiffness of the various specimens enables us to access the real experimental initial crack length, which was smaller than the nominal value, by comparison of the experimental values with the numerical ones. From the second part of the curve, the strain energy release rate values for the crack propagation in the initial step (G_l) and in the steady step (G_c) are deduced. They were calculated from a least-squares linear fit obtained from the load-point displacement versus the inverse square of the load curve. The experimental results are discussed in light of an analytical analysis using the thin beams approach, improved with an elastic foundation model developed by Maugis, describing the deformation of materials behind the crack tip, and of a numerical approach based on a finite element analysis. In this numerical model, an elastic-plastic behavior of the materials has been assumed. Analytical and numerical approaches are compared and their validity and limitations are discussed.     

Sphere packing with a geometric based compression algorithm

An efficient algorithm for the random packing of spheres can significantly save the cost of the preparation of an initial configuration often required in discrete element simulations. It is not trivial to generate such random packing at a large scale, particularly when spheres of various sizes and geometric domains of different shapes are present. Motivated by the idea of compression complemented by an efficient physical process to increase packing density, shaking, a new approach, termed compression algorithm, is proposed in this work to randomly fill any arbitrary polyhedral or cylindrical domains with spheres of various sizes. The algorithm features both simplicity and high efficiency. Tests show that it takes 181 s on a 1.4-GHz PC to complete the filling of a cylindrical domain with a total number of 26,787 spheres, achieving a packing density of 52.89%.     

浙江省主要类型土壤中元素的环境背景值

本文首次提供了浙江省主要类型土壤及其不同发生层次中的A_a、C_d、C_o、C_r、C_u、F、H_g、Mn、P_b、S_e、V和Z_n等13个微量元素的环境背景值系统数据,并研究了它们在土壤中的地球化学行为,从而为浙江省土壤环境质量评价、国土整治、环境污染监测等工作提供了重要的基础资料和依据。     

基于平衡理论的模拟移动床工艺参数鲁棒寻优

在模拟移动床的实际工作过程中,由于进料浓度和温度变化以及色谱柱填充不一致等因素影响,初始工艺参数作业下的分离性能可能会出现下降。首先对模拟移动床的机理模型进行了分析;然后在色谱分离平衡理论的基础上,使用有限元正交配置法求解模型得到新的工艺参数点;最后以果葡糖浆组分分离为对象,使用所提方法求解有扰动作用时的优化工艺参数,结果显示果糖纯度的合格率从81%提高到99%,证明其具有良好的鲁棒性。     

电感耦合等离子体串联质谱法测定高纯氧化钆中20种痕量元素含量

建立了电感耦合等离子体串联质谱法(ICP-MS/MS)直接测定高纯氧化钆中20种痕量元素含量的分析方法.在优化的实验条件下,分别采用He碰撞模式和NH3原位质量模式消除了Fe、As、Yb、Lu受到的质谱干扰,考察了基体效应以及不同内标元素的校正效果,方法定量限在0.003～0.63μg/g之间,RSD(n=7)≤5％,...