含有非水相液体(苯)的土壤气相抽提体系传质实验研究

选取砂土作为实验室一维土柱通风实验的研究对象,考察了不同含水量(0%、21.9%、36.6%及51.2%)条件下,苯在气-水-油-固4相共存的土壤气相抽提体系(Soil vapor extraction,SVE)体系中的相间传质过程。并用局部相平衡模型及非平衡动力学模型预测结果与实验结果进行了比较。干燥情况下,局部相平衡模型可以描述通风过程,随着含水量的增加实验结果严重偏离平衡模型。含水量为21.9%、36.6%及51.2%时,非平衡动力学模型与实验结果较为符合。结果表明,土壤含水量影响气-液(Non-aqueousphase liquid,NAPL)间的传质,干燥土壤中相平衡模型可以描述SVE修复过程。随含水量的增加修复进程偏离相平衡模型较严重,此时需要用非平衡动力学模型来描述。     

离子扩散与交换的一级动力学方程中平衡吸附量的讨论与确定

在应用一级动力方程来拟合土壤离子吸附动力学数据时，其关键是确定准确的平衡吸附量Ｎ∞的值，错误的或不符合方程本身在数学上要求的Ｎ∞的值，均会使拟合结果得出错误的结论。本文从理论上对化学机制与扩散机制的一级动力学方程进行了分析，提出了确定Ｎ∞值的方法，并在离子扩散与交换的动力学实验是得到了验证。     

木塑层合板的制备工艺及抗弯性能

为了弥补常规木塑复合材料的力学性能较低的不足,满足木塑复合材料在结构领域中的应用要求,试验以国产速生杨木为研究对象,以聚乙烯和聚丙烯塑料合金为粘结剂,采用平压法制备了结构用木塑层合板。通过研究热压温度、木材塑料质量比和马来酸酐添加量等3个因素对木塑层合板胶合性能的影响,以优化其制备工艺;在此基础上,进一步研究和分析了木塑层合板抗弯性能的影响因素及其作用机理。结果表明,拉伸剪切荷载作用下,偶联剂的介入,木塑层合板的破坏模式由空白试件的界面分层剥离转变为木材拉伸断裂;试验范围内,温度为180℃、木材塑料质量比为3/2、马来酸酐添加量为4%时木塑层合板的胶合性能较优,胶合强度达到0.98MPa,与未添加偶联剂的空白试件相比,胶合强度提高16.7%;采用层积法制备工艺,木塑层合板的抗弯性能能够达到结构用材的要求;密度0.6和0.8 g/cm3时,木塑层合板随着板材密度和木材塑料质量比的提高,静曲强度增大、抗弯弹性模量降低,木材单层板形态完整;密度为1.0 g/cm3时,随着木材塑料质量比的提高,木塑层合板静曲强度降低、抗弯弹性模量提高,当木材塑料质量比为3∶3时,木塑层合板中木材横纹出现大量不连续裂纹,木材的形态完整性下降;热压温度190℃、木材塑料质量比3/2和3/3、马来酸酐添加量为4%、板材密度为0.8 g/cm3时,制备的木塑层合板抗弯性能较优,能够达到100E等级的要求;结果可为木塑层合板在结构领域中的应用提供参考。     

菲在不同性质黑炭上的吸附动力学和等温线研究

在300、500和700℃3种条件下加热木屑制备得到3种黑炭,并对其结构和组成进行了表征。通过吸附动力学实验和平衡吸附实验,研究了菲在这些黑炭样品上的吸附动力学和平衡吸附,分别应用拟一阶、拟二阶和叶洛维奇3种动力学模型及Freundlich吸附等温方程对实验数据进行了拟合。结果表明,菲在黑炭样品上的吸附可以分为极快吸附、快吸附和慢吸附3个阶段,拟一阶动力学和叶洛维奇动力学方程仅能对菲在黑炭上吸附动力学的某个阶段拟合较好,而拟二阶动力学模型可较好地拟合菲的整体吸附动力学过程。说明菲在黑炭上的吸附由多个过程控制,水膜扩散、吸附剂颗粒表面扩散和吸附剂内部微孔扩散等多个过程导致了其吸附动力学的复杂性。在快吸附阶段,菲在各个黑炭上吸附动力学的差异,主要受黑炭疏水性影响。Freundlich模型对吸附等温数据的拟合结果进一步证实,多环芳烃菲在黑炭样品上的吸附受多种机制影响。     

水田平地机刚柔耦合多体动力学建模及验证

针对将水田平地机视为纯刚体多体结构不能反映其实际动力学特性,且机械系统动力学计算机仿真结果难以有效验证手段.该文提出刚柔耦合的平地机多体动力学模型及一种基于高速相机的模型运动学参数验证方法.其特点是结构与力学分析来对物理对体系统进行动力学建模,再通过计算机软件实现仿真,及非接触式的刚体质心与其姿态角的动态确定方法.从水田平地机机械结构、工作原理与实践结果出发,将平地机作业时变形较大杆件平行连杆作为柔性体,建立其多体机械系统的刚柔部件与运动副约束,即确定其动力学模型,以调平系统动力学部分为例借助多体动力学建模软件MapleSim对模型进行仿真,得到典型动态激励作用下的平地铲质心位置点的三维坐标与平地铲的姿态角;然后在实际激励信号作用下利用高速相机及其图像分析软件TEMA测得平地铲表面不在同一直线上的3个目标点的三维坐标,基于这些点的坐标求解平地铲质心位置与姿态角度作为测量结果,与仿真结果对比实现模型验证.验证结果表明:平地铲仿真结果与实际测量结果运动规律基本一致,平地铲质心位置误差最大误差约为10 cm.验证平地机建模方法可行性,该文提出的结构与理论分析建模-计算机仿真-基于图像分析的运动参数测量实现模型验证的机械系统设计方法对农机作业机械动力学建模与验证具有普遍适用性.     

坚果壳类生物质慢速热解动力学分析

为研究坚果壳生物质的慢速热解动力学过程，对两类坚果壳类生物质(花生壳和葵花瓜子壳)进行了低升温速率下惰性气氛的热重分析实验。采用竞争型热解反应动力学模型描述它们的热解过程。在原有动力学机理函数的基础上，提出了一种新的经验动力学机理函数。利用现代优化技术——模式搜索法，对实验数据进行了动力学分析，结果表明：新动力学机理函数能有效描述坚果壳类生物质的慢速热解动力学过程。     

溶液初始pH值及裂解温度对玉米秸秆基生物炭吸附Cr（遇）的影响

以玉米秸秆为原料,在300、450益和600益下裂解得到3种生物炭,通过批处理实验讨论了溶液初始pH值和裂解温度对玉米秸秆及其生物炭吸附Cr（遇）的影响,并用吸附动力学模型和等温吸附模型对实验结果进行拟合。结果表明：对于同种吸附材料而言,溶液初始pH值越低,玉米秸秆及其生物炭对Cr（遇）的吸附量越大;当溶液初始pH值为3或5时,对Cr（遇）的吸附性能大小顺序为：玉米秸秆>生物炭300益>生物炭450益>生物炭600益;当溶液初始pH=1时,对Cr（遇）的吸附性能大小顺序为：生物炭300益>玉米秸秆>生物炭450益>生物炭600益,且生物炭300益对Cr（遇）的最大吸附量约为141.24 mg·g-1。可见,溶液初始pH值越低,生物炭的裂解温度越低,越有利于生物炭对Cr（遇）的吸附。     

城市河流淤泥中重金属释放规律的研究

研究了哈尔滨何家沟淤泥中Cu、Pb、Zn、Cd释放的动力学过程及其影响因素,并用二级反应动力学等方程对其进行描述。结果表明,二级反应动力学方程拟合效果最好(r>0.9,n=17,p=0.001),释放速率为Cd>Zn>Cu>Pb,最大释放量为Zn>Cu>Cd>Pb,释放程度为Cu>Zn>Cd>Pb。影响因素实验结果显示,pH值对重金属的释放影响最大,而温度、盐度、泥水比的影响相对较小,且随着温度、盐度、泥水比的升高,淤泥中重金属的释放量呈增加趋势。     

炭化苹果枝皮和木材对水中硝态氮和铵态氮的差异吸附

将苹果枝条的皮层和木材部分开后在450℃下低氧加热制得炭化枝皮和炭化木材,分析其超微结构及对铵态氮和硝态氮的吸附。结果表明,苹果枝皮比其木材部分的纤维素含量高,有更多的微观孔洞和沟壑,炭化后纵向沟壑和孔隙更发达。炭化枝皮对NH4+—N和NO3-—N的饱和吸附量分别为24.11,12.93mg/g,炭化木材的相应参数分别为22.24,11.99mg/g,炭化枝皮对NH4+—N和NO3-—N的吸附能力均比炭化木材的更强。两者对NH4+—N的吸附量比对NO3-—N的更大,吸附过程均能采用Freundlich和Langmuir等温吸附模型、准二级动力学模型和Elovich模型拟合。炭化枝皮的吸附能力比炭化木材更强,与其原料纤维素含量高及微观沟壑发达有关。     

广西木兰科木材识别、材性与用途

通过对木兰科5个属15种木材进行宏观与微观构造的观察,用对比、分析方法研究,以及经过木材各项物理力学试验的测定及计算结果,分别编制木材宏观和微观识别检索表。木材多数属于高质量系数,弦径干缩比多数为中的一级,本科木材结构细致、均匀、不重不硬、切削性能好、用途广泛,是我国南方常绿阔叶树林的重要树种。     

Differential scanning calorimetry evidence of the enhancement of beta-sitosterol absorption across biological membranes mediated by beta-cyclodextrins

beta-Sitosterol is a plant sterol that has received much attention because of its effectiveness in reducing the absorption of dietary cholesterol, as well as in offering protection from cardiovascular diseases and cancer development. Thus, the knowledge of the interaction of beta-sitosterol with biological membranes can help in understanding its mechanism of action. In the present paper, the differential scanning calorimetry technique has been used to study the interaction of beta-sitosterol with a biomembrane model constituted by dimyristoylphosphatidylcholine multilamellar vesicles. Furthermore, kinetic experiments have been carried out to follow the uptake of beta-sitosterol by biomembranes and the effect of beta-cyclodextrins on such a process. Our results indicate that opportune concentrations of beta-cyclodextrins improve the uptake of beta-sitosterol by phospholipid membranes.     

应用多级反应动力学模型研究土壤甲氨基酚吸附

Metolachlor retention on a Sharkey clay soil was quantified using a kinetic batch method for different initial solution concentrations.Time-dependent adsorption was carried out by monitoring solution concentration at different reaction times.Adsorption was kinetic multireaction model which includes reverible and irreversible retention processes of the equilibrium and kinetic types,The predictive capability of the model for the dexcription of experimental results for metolachlor retention was examined and proved to be adequate。     

Wine distillery wastewater degradation. 2. Improvement of aerobic biodegradation by means of an integrated chemical (Ozone)-biological treatment.

Biological degradation of vinasses, generated during alcohol production from wines and pressed grapes, has been studied in four digesters operating in fill and draw mode. Digesters 1 and 2 were fed with nonozonated and ozonated mixtures of vinasses and domestic sewage (1:10 by volume), respectively. Digesters 3 and 4 operated with pure vinasses at acid and neutral pH values, respectively. The effects of pH, temperature, and ozone dose conditions were studied. Preozonation removed inhibitory compounds and improved the growth of nitrifiers. Ozone dose is the key variable to treat a vinasse-domestic sewage effluent effectively with a combined chemical-biological system. Contois's kinetic model has been applied to experimental results, and kinetic parameters related to the maximum specific growth rate of microorganisms, mu(max), and inhibitory effects, alpha, were calculated and compared for nonozonated and ozonated wastewaters.     

A new splash cup to measure the kinetic energy of rainfall

Splash cups have long been successfully used for both the quantification of kinetic energy of rainfall and the detachability of soil particles by rainfall impact, the so‐called “splash erosion”. Measurements of kinetic energy, however, have been difficult to operate in the field especially in remote areas, on steep slopes, and in forests since boundary conditions need to be controlled precisely. This paper introduces a new splash cup based on Ellison's archetype that reliably and accurately measures kinetic energy as a function of sand loss under a large variety of conditions. The Tübingen splash cup (T splash cup) is relatively easy to operate under harsh field conditions, and it can be used in experimental designs with a large number of plots and replications at reasonably low costs. The cup is constructed from plastic laboratory flasks and plastic pipes from water‐supply equipments. The unit sand is held by a removable carrier system that can easily be replaced in the field. The splash cups have been calibrated in combination with a laser distrometer using a linear regression function with r² = 0.98. They measure kinetic energy over a wide range of rainfall intensities from 0.6 to 40 L m^–2 h^–1. Kinetic energy per area varies between 10 and 250 J m^–2. Two years of field test measurements in a subtropical forest ecosystem in China proved the reliability, durability, and usability of our new splash cups and allowed detecting differences in kinetic energy between different tree species and biodiversity levels.     

平面运动刚体的动能基点

本文对作平面运动的刚体若任选其上一点Ａ为基点，在其平面运动被看成随Ａ点的平动和绕Ａ点的转动的同时，其动能可否表示为这一问题，提出了动能基点的概念。文中就动能基点的存在及其分布规律进行了讨论，并给出确定动能基点位置的方法及其应用实例。     

Fenton Reagent Advanced Oxidation of Polynuclear Aromatic Hydrocarbons in Water

Aqueous oxidation of three polynuclear aromatic hydrocarbons, fluorene, phenanthrene and acenaphthene with the combination of hydrogen peroxide and ferrous ion, Fenton reagent, has been studied. The effect of variables such as concentration of both reactants, pH and presence of bicarbonate ion and humic substances has been investigated. Products resulting from oxidation have also been identified. From experimental results and kinetic data determined the process is confirmed as an advanced oxidation involving the generation of hydroxyl radicals. Oxidation rates are even higher than those from other advanced oxidation systems involving ozone, UV radiation and hydrogen peroxide. Reactivity is in the following decreasing order: Phenanthrene > Fluorene > Acenaphthene.     

Kinetics Characteristics of Biofilm Reactors

A numerical model of biofilm reactors was tested using Monod typebiological kinetics in terms of the properties of feed solutionand dispersion. The model is based on computer techniques andthe numerical evaluation of the normalized biofilm mathematicalmodel. The effect of inlet parameters including concentration,flow rate, mass transfer coefficient and biofilm thickness wereinvestigated using the computer program developed. The numericalmodel was also applied to experimental data to demonstrate itsvalidity. In thin biofilms kinetic coefficients and otherparameters such as molecular diffusivity can be determinedbased upon experimental results. In thick biofilms, however, anadditional kinetic parameter or any other quantity related tomass transfer is a prerequisite in the evaluation ofexperimental data.     

积分方法改进的生物质热解反应速率模型构建

针对经典Arrhenius方程中温度积分项不可积的问题,通过设定热解过程中生物质转化率同时为时间(和温度r的函数,使温度积分项可积分,有效避免积分法动力学分析中因简化而导致的计算误差。基于此热动力学方程(Ⅱ类热动力学方程)采用等转化率线性积分法求解反应活化能E,并结合模型拟合法选取最优反应机理函数,将选取的机理函数重新代入Ⅱ类热动力学方程积分式解得指前因子A的值。基于等转化率线性积分法分别采用Ⅰ类及Ⅱ类热动力学方程对玉米芯等5种生物质热解过程进行动力学分析,结果显示2类热动力学方程求得生物质活化能E的决定系数均高于0.95。Ⅱ类动力学方程求解的动力学参数计算的动力学分析值与试验值的吻合度高于Ⅰ类动力学方程。根据热解反应的活化能E与lnA具有高度线性拟合性,且转化率0.05～0.85间活化能波动不大这一特点,采用最大热解速率处转化率对应的热解动力学参数简化热解过程的动力学参数,可减小数值模拟的计算成本,为工程上热解反应的数值模拟提供一定的基础。     

Evaluation of the sorption process for imidacloprid and diuron in eight agricultural soils from southern Europe using various kinetic models

Kinetic studies are of great concern for understanding the processes and parameters involved in the sorption of pollutants by soils. Sorption kinetics of imidacloprid and diuron in eight soils of different characteristics, with very low organic carbon content were investigated. Pseudosecond-order kinetic reactions closely correlate with the experimental kinetic (R(2) > 0.98) in all soils. The sorbed amount of diuron was higher than that for imidacloprid. The low OC content of these soils correlated neither with the sorbed amount nor with the kinetic parameters for both pesticides. Imidacloprid sorption was correlated with silt and sand content and cation exchange capacity (CEC); meanwhile for diuron, no correlation was found. Thus, sorption kinetics take place throughout different mechanisms related mainly to the chemical character of the pesticides. Sorption kinetic parameters determined using three of the four models selected (pseudosecond-order kinetic reactions, Elovich equation, and Weber-Morris models) have been shown to be worthy to distinguish the process controlling the sorption kinetic of both pesticides.