基于一类Daubechies小波自相关函数的研究

讨论了一类Daubechies小波自相关函数的基本性质,着重对Daubechies尺度函数的自相关函数的插值分析做了仔细研究,得出了关于Daubechies小波尺度空间中的若干结果,并将其进一步推广.     

微波自动测量线系统与阻抗参数的CAT

根据手动测量的原理，将传统的微波测量线系统进行智能化、自动化和数字化改造，成为由PC机控制，自动测量，数据采集和处理、结果显示的微波CAT（Computer Aided Test）系统，并在此基础上实现了阻抗参数的CAT。     

Discretization of nonlinear systems with delayed multi-input via Taylor series and scaling and squaring technique

An input time delay always exists in practical systems. Analysis of the delay phenomenon in a continuous-time domain is sophisticated. It is appropriate to obtain its corresponding discrete-time model for implementation via digital computers. In this paper a new scheme for the discretization of nonlinear systems using Taylor series expansion and the zero-order hold assumption is proposed. The mathematical structure of the new discretization method is analyzed. On the basis of this structure the sampled-data representation of nonlinear systems with time-delayed multi-input is presented. The delayed multi-input general equation has been derived. In particular, the effect of the time-discretization method on key properties of nonlinear control systems, such as equilibrium properties and asymptotic stability, is examined. Additionally, hybrid discretization schemes that result from a combination of the scaling and squaring technique (SST) with the Taylor series expansion are also proposed, especially under conditions of very low sampling rates. Practical issues associated with the selection of the method’s parameters to meet CPU time and accuracy requirements, are examined as well. A performance of the proposed method is evaluated using a nonlinear system with time delay: maneuvering an automobile.     

Application of atomic force microscopy and scaling analysis of images to predict the effect of current density, temperature and leveling agent on the morphology of electrolytically produced copper

Atomic force microscopy (AFM) was used to study the morphology of electrodeposited Cu at current densities from 183 to 253 A m⁻². Digital image analysis was employed to parameterize the morphological information encoded in AFM images and to extract information concerning the mechanism of the electrodeposition reaction. It has been shown how the limiting roughness, δ, the critical scaling length, L_c and the aspect ratio, 4δ/L_c, vary as a function of the deposition time and electrodeposition conditions, such as temperature, current density and the amount of organic additives. It has been demonstrated how laboratory experiments of short duration and the scaling analysis of AFM images can be used to predict roughness of the metal sample after 2 weeks of industrial electrorefining.     

油田垢样分析检测方法与应用

以现场垢样为例,提供了一种结垢油井垢样的分析检测方法。即称取一定量的垢样进行干燥、焙烧,以确定该垢样为有机垢样或无机垢样;若该垢样为有机垢样,根据行业标准进行蜡含量、胶质、沥青质含量的测定;若该垢样为无机垢样,进行定性分析后用盐酸溶解,然后根据行业标准进行钙离子、镁离子、铁离子、硫酸根离子以及硅离子含量的检测。该方法对垢样进行快速定性、定量分析,操作简单、快速、误差小。     

一种复合阻垢剂在玉米浆蒸发器上的应用研究

通过对某淀粉厂玉米浆蒸发器上的玉米浆、垢样进行分析,并结合外在控制指标对玉米浆质量的影响,研究了该玉米浆蒸发器的结垢问题。结果表明,该玉米浆蒸发器有明显的碳酸钙、硫酸钙结垢倾向。针对玉米浆蒸发器温度较高、玉米浆中有机质含量高、粘度高的特点,开发出一种适合该环境的复合型阻垢剂。现场应用研究表明,当加药浓度为100 ppm时,成垢离子Ca~(2+)、SO_4~(2-)、CO_3~(2-)的保有率均有明显提高,玉米浆蒸发器的结垢倾向得到了有效控制。     

Quantitative biofouling diagnosis in full scale nanofiltration and reverse osmosis installations

Biofilm accumulation in nanofiltration and reverse osmosis membrane elements results in a relative increase of normalised pressure drop (ΔNPD). However, an increase in ΔNPD is not exclusively linked to biofouling. In order to quantify biofouling, the biomass parameters adenosine triphosphate (ATP), total cell count and heterotrophic plate count in membrane elements were investigated during membrane autopsies and compared with ΔNPD in test rigs and 15 full scale investigations with different types of feed water. The combination of biomass related parameters ATP and total cell count in membrane elements seem to be suitable parameters for diagnosis of biofouling, whereas plate counts were not appropriate to assess biofouling. The applied ΔNPD measurement was too insensitive for early detection of fouling. Measurements of biological parameters in the water were shown to be not appropriate in quantifying biofouling. Evidently, there is a need for a practical tool, sensitive pressure drop data and systematic research.     

Scaling fire whirls

A fire whirl in an open space can cause devastating damage as was experienced in Hifukusho-ato, Tokyo, after the Great Kanto Earthquake in 1921. To understand the generation mechanism of the open-space fire whirls, 1/1000th scale-model experiments were conducted in a large, low-speed open-loop wind tunnel. In analyzing the experiments, there was found to be a critical lateral wind velocity that generated intense fire whirls. A scaling law that predicts the critical wind velocity was developed and validated by various data including scale-model experiments by other researchers and real urban fire whirls. A dimensional analysis is conducted to understand the effect of flow circulation on the increase in flame height. The simple analysis was supported by the results of numerical simulations by other researchers.     

油浆阻垢剂的工业应用

油浆系统是催化分馏系统的核心,其运行好坏直接影响整套催化装置的安、稳、长、优生产。近年来,随着原料油的密度越来越重,导致油浆系统的结垢越发严重,轻者造成装置减产,重者迫使装置停工。文内分析了油浆系统的结垢机理,介绍了洛阳石化总厂在增上阻垢剂之前采取的相应措施,并结合油浆系统的结垢原因阐述了油浆阻垢剂的作用原理。该厂于1996年增上了油浆阻垢剂注入系统,装置经过两个生产周期的运行,油浆循环量始终维持在正常水平,装置未出现因设备或管线堵塞而产生的不良后果,油浆系统可调控自如。并对油浆阻垢剂加注前后,泊浆系统操作参数进行了对比,通过对比看出,管线和设备的结垢问题基本得到了解决。油浆阻垢剂投用3年来,减轻了油浆系统的结垢问题,消除了事故隐患,为催化装置的长周期安全运行提供了保障,每年可增加效益170余万元。     

清洗高压注水管线硬质垢的圆盘清管器

针对油田高压注水管线硬质垢的清洗难题,研制开发了一种加强型圆盘清管器。通过现场试验,确定了清洗工艺流程和参数,同时验证这是一种较理想的机具,除垢率达 ９５％以上,且操作简单成本低廉,值得推广应用。