A new method for separation of 2D incident and reflected waves by the Morlet wavelet transform

A new method based on the Morlet wavelet transform for separating a 2D wave field into incident and reflected waves is proposed in this paper. The principle of this method, first, is derived for constant depths. Then, using the linear shoaling theory, the method is extended to an arbitrary sloping bathymetry. Owing to the time-frequency characteristic of wavelet transform, the present method can separate waves in the real time domain and is not confined by the stationary assumption of waves. The efficiency and accuracy of this method are demonstrated using numerical simulated data.     

Flow around a partly buried cylinder in a steady current

The flow around a cylinder, surface mounted or partly buried has been examined at Reynolds number of 1.3×10⁴ and 2.6×10⁴ by using the flow visualization method in the case of steady current. The lengths of the upstream and downstream separation regions were determined and the characteristics of the flow area were discussed for the cylinder having different burial depth to the diameter ratio (G/D). For comparsion, some numerical results obtained from the application of the FLUENT, computational fluid dynamics (CFD) software package have also been presented. Both experimental and numerical results indicated that the lengths of the separation regions near the upstream and downstream of the cylinder decreased with the increasing burial ratio (G/D=0, 0.20, 0.50). The results have significant implications both for the illustration of the potential for using CFD software and highlighting the need for data of two dimensional flow around the buried cylinder.     

Bildungsbedingungen von Zinkferriten im Hinblick auf die Entfernung von Schwermetallen aus Abwässern durch Magnetseparation

Conditions of the Formation of Zinc-bearing Ferrites in Regard of Heavy Metal Removal from Wastewater by Magnetic Separation Magnetic separation techniques can be applied for heavy metal removal from wastewater if it is reached to link together the heavy metals with a substance which is sufficiently influenced by a magnetic field. Such a substance is the ferrimagnetic magnetite which can be prepared under special conditions – by oxidation of ferrous hydroxide – in wastewater. In this paper, zinc was chosen as an example for technically relevant, diamagnetic heavy metals. The investigations deal with the influence of zinc onto the structure and the magnetic properties of the reaction products produced by oxidation of zink-bearing ferrous hydroxide in aqueous solutions at room temperature. The oxidation was caused by synthetic air passing through the suspension. During the reaction, the parameters pH value, redox potential, and concentration of dissolved oxygen were observed continuously. The plots of these parameters versus time yield typical courses which can be used as measurement for the progress of the reaction. The results show that magnet ite can only be prepared if the molar ferrous concentration at the beginning is four times higher than the concentration of the dissolved oxygen. Furthermore, the oxidation rate must be slow, a condition which could be achieved by mass transfer controlled kinetics. The products of the oxidation of zinc-bearing ferrous hydroxide show a colour between black and brown. They consist of magnetite, zinc-bearing ferrite and amorphous iron hydroxide. It can be observed that with increasing initial zinc concentrations, increasing amounts of zinc-bearing ferrite but also of amorphous iron hydroxide are produced. Therefore, it seems that the impact of zinc on the reaction is in such a way that more amorphous compounds instead of the thermodynamically stabile ferrite are formed; The magnetic properties show also a dependence on the initial zinc concentration: The saturation magnetization decreases with an increase of the zinc concentration. The reaction product which results from the experiment with an initial mole ratio of Zn:Fe = 1:1 points out only paramagnetic behaviour.     

硼特效树脂离子交换法分离硼的研究

本文对AmberliteIRA743硼特效树脂交换分离础的特性及其影响因素进行了研究.它适用于各种地质作品中硼的分离提取，特别是在硼同位素地球化学研究时。必须进行础纯化的场合。     

Diffraction of oblique waves by thick rectangular barriers

A complete analytical solution is presented for the linear diffraction of oblique waves by horizontal rectangular cylinders either fixed at the free surface or mounted on the sea bed in a finite-depth of water. Helmholtz equation is employed as the governing differential equation obtained by reducing the 3-D oblique wave scattering problem to a 2-D case. According to the method proposed, the fluid region is divided into three sub-regions in which the governing differential equation is solved by the separation of variables. The solutions for each region are then matched on the common boundaries of sub-regions to determine the unknowns of the eigen series expansions and Fourier series. Thus transmitted and reflected waves are obtained in the far-field, and forces and moments acting on the rectangular cylinder fixed at the free surface are also given. Comparisons are made in order to check the accuracy of the method.     

Chromatographic Separation and Analytic Procedure for Priority Organic Pollutants in Urban Air

A separation procedure was developed for analysis of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in urban air, while simultaneously eliminating the interfering compounds. This was carried out by optimization of a column chromatograph with regard to the eluent type (n‐hexane and n‐pentane), volume of eluent, type of sorbent material (silica gel and florisil) and activation level of the sorbent material. The determination of the level of PCBs and PAHs was carried out using gas chromatography (GC) equipped with a mass selective detector (MSD), while determination of the OCPs was carried out by GC equipped with an electron capture detector (μ‐ECD). The use of a silica gel column (10 g, 5% deactivated with H₂O) with 70 mL of n‐hexane gave satisfactory separation of PCBs from PAHs and OCPs. After collecting the PCBs with 70 mL of n‐hexane, 3·20 mL of n‐hexane:ethyl acetate, (1:1, v:v) was adequate for elution of the PAHs and OCPs from the column. The primary aim of this study was to develop a multimethod for analyses of PCBs, PAHs, and OCPs in urban air as well as reducing solvent and sorbent consumption and analysis time during the clean‐up procedure compared to the US EPA standard methods (EPA methods TO‐13A for PAHs and TO‐4A for both PCBs and OCPs).     

Banded structure of drifting macroalgae

A massive bloom of macroalgae occurred in the western Yellow Sea at the end of May, 2008, and lasted for nearly 2 months. The surface-drifting macroalgae was observed to accumulate in a pattern dominated by linear bands. The maximum length of individual algal bands exceeded 10 km and the distance between neighboring bands ranged from hundreds of meters to 6 km. Seven satellite images were analyzed to determine the distances between neighboring bands. Proportions of about 24%, 38%, and 22% are responsible for the separation distances smaller than 1 km, between 1 and 2 km, and between 2 and 3 km, respectively. The separation of about five percent of the bands exceeds 4 km. The probability distribution of the separation distance is quite close to log-normal which is that found in Langmuir circulation. However, the observed algal band separation greatly exceeds the distances between convergence lines reported in Langmuir circulation.     

龙游灵山多金属黄铁矿选矿研究与开发利用分析

本文从选矿试验的结果出发，总结矿石的选矿规律，剖析产生的地质资源原因，并在此基础上提出灵山矿区分步建设，即先形成采矿能力，后建选矿厂。     

Quantitative Separation of As(III) and As(V) from a Synthetic Water Solution Using Ion Exchange Columns in the Presence of Fe and Mn Ions

The quantitative separation of As(III) from a water sample containing As(III) and As(V) in the presence of Fe and Mn in an ion exchange resin (AG1 X8) column for the speciation of arsenic is described. Individual and combined effects of Fe and Mn on the separation of As(III) from the solution have been studied separately. In absence of Fe and Mn, the ratio between the As(T) concentration in the eluent and the As(III) concentration in the original sample has been found to be 0.9717 under optimum process conditions. The presence of Fe(II) in the water sample increased the As(T) concentration in the eluent whereas Mn(II) decreased it. Combined effects of Fe and Mn on the percentage increment in the eluent arsenic concentration have been expressed by additive and interactive models. The interactive model has been developed by a statistical software with a 95 % confidence level. In most of the cases the error on the determination of the As(III) concentration had a minimum when using the interactive model.     

三元体系CaCl2-SrCl2-H2O相平衡在高钙锶比卤水体系中分离提取氯化锶的应用

采用等温溶解平衡法测定了三元体系CaCl₂-SrCl₂-H₂O温度在353.15 K时共饱和点的溶解度。基于实验结果和文献已有报道的该体系多温下的相平衡数据,模拟了南翼山油田卤水中氯化钙和氯化锶在温度323.15 K下的分离实验。模拟钙锶分离实验结果表明,物质的量比为25.41∶1的CaCl₂和SrCl₂的混合溶液在323.15 K下蒸发结晶提纯后的固相中钙锶物质的量比降低为1.73∶1,SrCl₂的回收率为52.47%,将所得一次固相产品在323.15 K下溶解并再次蒸发后,钙和锶的物质的量比从1.73∶1降至1.1∶1,SrCl₂的回收率为78.67%,SrCl₂的总回收率为41.28%。