Gd3Al5O12：Eu^3＋柠檬酸盐硝酸盐燃烧法合成及其发光性能研究

采用柠檬酸盐硝酸盐燃烧法，在较低的温度（900℃）下成功地合成单一晶相Gd3Al5O12：Eu^3＋发光粉体，紫外激发荧光光谱分析表明，粉体615m和593m荧光发射源于Eu^3＋的^5D0-^7F2和^5D0-^7F1跃迁．该方法中各工艺条件（如pH值、柠檬酸／金属离子比、煅烧温度）对Gd3Al5O12：Eu^3＋发光性能均有影响，通过试验得出了获得最佳发光性能荧光粉体的工艺参数．     

固定化啤酒废酵母对Pb^2＋吸附性能的研究

固定化啤酒酵母法是采用啤酒废酵母作为生物吸附剂,研究其在固定化的条件下对Pb^2＋的吸附特性。用2％海藻酸钠与1％明胶混合作为包埋剂固定啤酒废酵母。考察了固定化啤酒废酵母吸附Ph^2＋过程中的影响因素,包括初始Pb^2＋浓度、酵母菌体渡度、吸附时间和初始pH值等。试验结果表明,在初始Pb^2＋质量浓度为100mg／L、pH值为5、菌体酵母投加量为1.44g/L、吸附时间为180min的最佳条件下,固定化啤酒废酵母对Pb^2＋的吸附率为92.69％,吸附量为51.35mg／g,吸附符合Freunollich方程,相关系数R为0.99014。     

用D_2EHPA-煤油溶剂萃取分离L-异亮氨酸

本文研究了从发酵液中用D2EHPA－煤油溶剂萃取分离L－异亮氨酸工艺．考察了萃取时pH值、萃取剂浓度和异亮氨酸浓度对于异亮氨酸和缬氨酸的萃取分配比的影响．在计算机上进行回归，得到以下分配模型：当1≤pH≤3．5时lgDIle＝0．09906pH2＋0．8625pH＋2．2696lgCHR－0．09188lg2CIle＋0．1766lgCIle－1．366lgDrmVal＝－0．0293pH2＋0．550pH＋1．2659lgCHR－0．2420lg2CIle＋0．4549lgCIle－1．696用此模型，应用分馏萃取理论，进行逐级计算，求取了萃取工艺的主要参数，并在φ20mm的多级离心萃取器上对上述结果进行了验证．结果表明：当CHR浓度为1．5mol／L，相比V：L：L’＝2：1：2，N’＝3，N＝6时，异亮氨酸的收率达到90％以上，纯度＞99％．实验取得了较为满意的结果．     

水合霉素的高效液相色谱分析

采用高效液相色谱法分析水合霉素。使用C18反相柱和二极管阵列检测器，以0．1mol／L草酸铵溶液＋二甲基甲酰胺＋0．2mol／L磷酸氢二铵溶液=75＋15＋10（v／v/v）（用氨水调pH值至8．0左右）为流动相，柱温30℃，流速0．8ml／min，检测波长365nm，外标法对水合霉素的有效成分进行定量分析。其标准偏差为0．22，变异系数为0．25％，平均回收率为99．86％，R=0．9999。与生物效价法比较，该方法操作简单快速，定量准确可靠，适用于产品的常规分析和质控研究。     

聚乙烯亚胺辅助超滤法处理含锶含钴废水

研究了聚乙烯亚胺（PEI）辅助超滤处理含重金属离子锶（sr2＋）和钴（Coz＋）的废水。重点考察了PEI与重金属离子的质量浓度比（P／M），溶液pH以及离子强度对sr^2＋和Co“截留率的影响。结果显示PEI去除sr^2＋和Co^2＋的最适pH为5和9，去除两种金属离子的最佳P／M值均为10。在最佳P／M值和最适pH时，对锶和钴的截留率分别为59％和100％。试验结果表明使用PEI辅助可以大大提高超滤膜对重金属废水中Sr^2＋和C0^2＋（尤其是con）的去除效率。     

好氧颗粒污泥吸附重金属Cd(Ⅱ)的研究

以好氧颗粒污泥作为一种新型的生物吸附剂，对水中Cd^2＋进行吸附研究。分析了初始Cd^2＋浓度、初始污泥浓度以及pH值对吸附的影响。试验表明，Langmuir等温方程和Freundlich等温方程都能拟合试验所得吸附数据。当溶液温度维持在25℃时，pH值为6～7时具有较好的吸附效果。在此条件下，当Cd^2＋的质量浓度为5～150mg／L．吸附时间为4h时．颗粒污泥最大吸附容量为69．7mg／g，最大去除率为95．9％。这说明颗粒污泥是一种有效的、经济的处理含Cd^2＋废水的生物吸附剂。     

氯化铝混凝处理含锌镉废水的研究

采用氯化铝对一种同时含Zn^2＋、Cd^2＋的废水进行了实验条件下的混凝处理，讨论了在搅拌速度及反应温度不变的情况下，AlCl3用量、溶液pH值、混凝时间对Zn^2＋、Cd^2＋除去效果的影响，找出了最佳处理条件。结果表明，用AlCl3处理该废水对Zn^2＋有很好的除去效果，对Cd^2＋有较好的除去效果；在室温下混凝处理该废水的最佳条件为：pH值为6或9，AlCl3用量为0.8g·L^-1，反应时间为30-40min。     

D401螯合树脂柱分离富集ICP—OES法测定水中的痕量Cu^2＋、Pb^2＋、Cd^2＋

提出了采用自制的D401螯合树脂柱分离富集一电感耦合等离子体原子发射光谱（ICP—OES）法测定水中痕量Cu^2＋、Pb^2＋、Cd^2＋的分析方法。探讨并确定了分离富集和仪器的最佳条件。试验表明,在优化的试验条件下Cu^2＋、Pb^2＋、Cd^2＋可被D401螯合树脂柱定量吸附,可采用25mLl．5mol／L的HNO,溶液完全洗脱,动态饱和吸附容量分别为101．9、205．3、176．7mg／g,方法测定Cu^2＋、Pb^2＋、Cd^2＋的检出限（3σ）分别为0．00041、0．00083、0．000361xg／mL,相对标准偏差（RSD,n=7）分别为2．3％、2．8％、3．1％,加标回收率在93．0％～104．0％之间,测定结果与电感耦合等离子体质谱法基本一致。     

Fenton法深度处理干法腈纶废水

采用Fenton法深度处理干法腈纶废水,试验中考察了Fe2＋投加量、H2O2投加量、pH、反应时间等l习素对CODcr处理效果的影响,确定了反应过程中的最佳工艺参数,并分析了该法处理废水的作用机理。试验结果表明：影响Fenton氧化的因素从大到小依次为H2O2投加量、初始pH值、反应时间、Fe2＋投加量。最佳试验条件为：e（Fe2＋）为18．0mmol／L,dH2O2）为49．0mmol／L,pH为3．0,反应时间为30min。在此条件下出水COD。可降至47．4mg／L,去除率可达到80．3％。显示该方法对于干法腈纶废水的处理具有巨大的前景和潜力。     

水合物热分解Stefan相变模型解的存在性及Laplace变换求解

天然气水合物热分解Stefan相变模型为二阶抛物线型偏微分方程(组)。开展了水合物热分解Stefan相变模型解的存在性、唯一性论证和Laplace求解方法的探索。演绎了简化的过程、细节的推导：应用微分方程的迭代格式，导出了最大、最小值引理和参数取值范围；通过边界上的交替条件映射对x_n(t)、T_n(x,t)的极限存在性的证明，证实了微分方程解的存在；采用反证法，证明了Stefan微分方程解的唯一性。运用Laplace变换、分离变量和Laplace逆变换法，求得了该Stefan模型的解析解，超越方程的单调性证明了方程解的唯一性。     

Separative Diffusion in the Transient State. III. Diffusion of a Heavy Fluid in a Cone

Abstract

Diffusion of a heavy fluid into a cone is approximately one-dimensional. This process can be calculated by the differential equation of diffusion with chemical reaction. Numerical computation was applied for the study of separative diffusion. Separation factors and output quantities were found for cone angles of +30, +5, and ?5[ddot] and for double barrier thickness. A periodic quasi-steady-state process is proposed which yields a reasonable output with tenfold steady-state separation.     

Adsorption and Diffusion of VO2+ and VO2 + across Cation Membrane for All‐Vanadium Redox Flow Battery

A method based on a selectivity coefficient and the Nernst‐Planck equation is proposed to determine diffusion coefficients of vanadium ions across a cation exchange membrane in VO²⁺/H⁺ and VO₂ ⁺/H⁺ systems. This simplified method can be applied to high concentrations of vanadium ions. Three cation exchange membranes were studied. The logarithmic value of the selectivity coefficient was linearly dependent on the molar fraction of vanadium ions in solution. The diffusion coefficient of vanadium ions decreased with decreasing water content. The membrane with the lowest diffusion coefficient was selected as a battery separator and showed the lowest capacity loss of the studied membranes.     

磷酸盐激光玻璃离子交换动力学研究

对Li2O质量分数不同的磷酸盐激光玻璃进行了离子交换实验,并研究了熔盐中K+及Na+在玻璃中的扩散动力学。使用波分散光谱(WDS)技术分析了K+及Na+在玻璃中的扩散深度,并研究了两种离子在玻璃中的离子扩散系数和扩散活化能。实验结果表明,玻璃中Li2O质量分数较高时,K+及Na+在玻璃中的扩散深度较大;混合碱效应导致离子的扩散系数降低。     

One-dimensional diffusion model in an inhomogeneous region

A one-dimensional model is developed to describe atomic diffusion in a graphite tube atomizer for electrothermal atomic adsorption spectrometry. The underlying idea of the model is the solution of an inhomogeneous one-dimensional diffusion equation, with the diffusion coefficient being a function of temperature over the entire inhomogeneous region. An analytical solution of the problem is obtained in the form of a Green’s function.     

Spatially resolved indiffusion behavior of Cu2+ and Ni2+ in polypropylene

Microplastics and their effects on the environment and food chain have become increasingly important in recent years. These polymer particles, which are only few millimeters in size or smaller, accumulate in the environment and can enter the human food chain via animals that ingest them. Moreover, they can accumulate impurities such as heavy metals. Therefore, this study focuses on the indiffusion behavior of metal ions into semicrystalline polypropylene (PP) applying time-of-flight secondary ion mass spectrometry (ToF-SIMS) at cryo-conditions. Diffusion coefficients of Cu²⁺ and Ni²⁺ in PP are determined by classical SIMS depth profiling in frozen state (T <−130°C) and subsequent data analysis according to Fick's second law of diffusion. The results show that diffusion of Cu²⁺ ions in dry PP (D_PP,Cu = [2.21 ± 0.15]·10⁻¹² cm²/s) is faster compared to Ni²⁺ ion diffusion of dry PP (D_PP,Ni = [4.43 ± 0.55]·10⁻¹³ cm²/s). Interestingly, the diffusion of Cu²⁺ ions in water-saturated PP (D_PP,H2O,Cu = [1.91 ± 0.28]·10⁻¹³ cm²/s) is slower compared to Cu²⁺ ion diffusion in dry PP. Furthermore, high-lateral resolution ToF-SIMS analysis shows that metal ions only diffuse in certain areas of PP, which are most likely amorphous.     

Diffusion coefficient measurements by solvent absorption in concentrated polymer solution

Diffusion coefficient measurements for solvents in concentrated polymer solutions require consideration of both concentration dependence of the diffusion coefficient and surface resistance to mass transport. Solutions to the diffusion equation have been generated where these effects are explored. A method to account for both concentration dependence and surface (absorption) resistance in the experimental determination of diffusion coefficients is given and demonstrated with an example where a multiplying factor of over 300 is required to adjust the apparent diffusion coefficient to the value sought.     

管道泄漏污染物一维迁移的LBM模拟

石油管道泄漏现象时有发生,对环境造成了危害,研究埋地管道石油污染物泄漏尤为关键。在此采用Boltzmann研究方法,通过多尺度技术和局部平衡态分布函数的Chapman-Enskog展开得到运算的平衡态方程,并给出了石油管道污染物泄漏迁移的一维有源扩散方程的格子Boltzmann模型,通过C++软件数值模拟进行运算。最终得出结果与理论解一致,验证了用Boltzmann方法研究污染物泄漏迁移的可行性。     

Transport of Eu3+ through a Bis(2-ethylhexyl)-phosphoric Acid,n-Dodecane Solid Supported Liquid Membrane

Abstract

The coupled transport of Eu³⁺ and H⁺ ions through a solid supported liquid membrane consisting of a porous polypropylene film immobilizing an HDEHP solution in n-dodecane has been studied as a function of the membrane area, stirring speed of the aqueous solutions, membrane composition, and acidity of the feed solution. The experimental results are in agreement with predictions derived from a theoretical permeability coefficient equation which assumes that membrane diffusion and aqueous film diffusion are the only rate-controlling factors.     

Activation Energy for Diffusion of 133 Xe Through MgO-Ni Cermet Compacts

The ¹³³ Xe was produced by irradiation of UO₂ which formed the central or core portion of small disks made from a 66% Ni and 34% MgO cermet material. Diffusion rates through this material were determined in the temperature range 800° to 1100°C. The activation energy for diffusion was determined to be 4.4 e.v. with the diffusion coefficient given by the equation D = 1.85 × 10⁷× sq. cm. per second. The mechanism of diffusion appeared to be of the atom-vacancy interchange type.     

Solids mixing in fluidized beds—a hydrodynamic approach

Solids mixing in fluidized beds has traditionally been treated using empirical transfer or diffusion coefficients. This study presents a new approach. A hyperbolic diffusion equation is derived by linearizing two phase flow equations of motion obtained previously by minimizing the rate of entropy production.Analytical solutions to the hyperbolic diffusion equation for a tracer concentration are obtained using Laplace transforms and the method of images. The solutions compare well with solids mixing experiments. The solutions involve a propagation velocity, which is determined by two phase mass balances, and a diffusion coefficient which is a ratio of kinetic energy to interphase friction or drag, as in Einstein's diffusion coefficient. Least square curve fits of data to the theory produced reasonable values of the drag coefficients.