基于μC/OS-II生物脱氮工艺中多参数实时检测

为实现对生物脱氮工艺中多参数的实时检测,以及解决常规化学检测过程中带来的污染和耗时问题。应用了一种基于电化学和嵌入式系统,可同时对水温、pH值、氨氮3个相关参数进行实时检测,并对理论值和实测值进行数据分析对比。实验结果表明,该系统实时性良好、稳定可靠,且满足了该工艺实时检测要求。     

基于最小均方误差选择参考节点的RSS测距定位算法

无线传感网中的多类应用均需要准确的定位算法.为了降低定位成本,减少能量消耗,常采用基于接收信号强度RSS(Received Signal Strength)测距,并建立相应的方程,再利用线性最小二乘LLS(Linear Least Squares)法求解节点的位置,将此定位算法记为RSS+LLS算法.RSS+LLS算法随机选择参考节点,这有损定位精度,同时,LLS算法并没有考虑每个测距值的误差,这些不足降低算法的定位性能.为此,提出基于RSS+LLS的优化算法,记为RSS+WLS+OPT算法.该算法先通过RSS测距,并基于最小均方误差原则选择参考节点,从而提高定位精度,同时,给每个测距值引入权重系数,采用基于协方差矩阵的加权最小二乘法WLS(Weighted Least Squares)求解节点位置,进而降低了测量误差对定位精度的影响.仿真结果表明,与RSS+ LLS相比,提出的RSS+WLS+OPT算法的定位精度提高了约2米,并没有增加计算时间,降低对测距误差的敏感性.     

自适应阵列抗干扰性能的解析定量分析

自适应阵列抗干扰性能常用输出信干噪比(Signal-to-Interference and Noise Ratio,SINR)损失、抗干扰改善因子(ECCM Improvement Factor,EIF)等来衡量,但目前尚缺乏解析的定量分析.为此,采用归纳法理论推导了均匀线阵条件下输出SINR损失、EIF等指标的解析表达式,定量获取了自适应阵列抗干扰性能.仿真实验验证了理论分析结果的有效性及快拍数对自适应阵列抗干扰性能的影响.     

有理二次Bézier形式共轭双曲线段的几何计算

考虑有理二次Bézier形式的相互共轭的双曲线的控制顶点之间的关系,给定表示一段双曲线的标准型有理二次Bézier曲线,目标是求出它的共轭双曲线上相应段的控制顶点。首先给出共轭双曲线段的自然定义;接着通过参数变换,将有理二次Bézier形式和一般参数形式进行转换,并把这种转换对应到矩阵,以给出所求控制顶点的显式表达;最后,给出表达式的几何意义,即共轭双曲线段的控制顶点可由原双曲线的控制顶点通过两次线性插值得到。     

2A12与2A11铝合金超声波焊接工艺与组织研究

对2A12-T3和2A11-O铝合金进行了超声波焊接,研究了不同超声波焊接工艺参数对焊接界面结合状况的影响.采用扫描电镜、电子背散射衍射和透射电镜研究了焊接界面的组织结构.结果表明,当超声波焊接振幅为30μm,焊接时间为0.2s,焊接界面结合状况较好,焊接界面的线性焊接密度接近100％.氩气保护也会对线性焊接密度产生影响.当焊接振幅为15μm时,氩气保护可提高线性焊接密度;但当焊接振幅为30μm,氩气保护对线性焊接密度无明显影响.超声波焊接过程中,焊接界面上产生波纹和漩涡状塑性流动,发生动态回复和连续动态再结晶,形成由位错缠结、位错胞、亚晶和细小晶粒组成的焊接界面组织.     

Black-box models for fault detection and performance monitoring of buildings

Black-box models such as linear regression have proven to be helpful in ongoing building commissioning in many ways. The aim of this work is to improve linear models with change point for fault detection in buildings. Building simulations revealed poor performance of them (R 2 2. Remark: In the Inverse Modelling Toolkit (IMT) (Kissock et al. 2003) similar models are called CP-MVR or rather 3P-MVR or 4P-MVR. The difference to the CPMLRs used here is that there are different intercept terms for all linear regressions for the CPMLRs instead of one equal intercept term for all linear regression models 3P-MVR. This is introducing discontinuities on continuous independent variables but for the mean daily perspective taken here this is not disadvantageous.  < 0.7) for some low energy buildings. The regression models (RMs) can be considerably improved by introducing the rate of change of the indoor air temperature (ΔT _ind) as an independent variable. Thus, R ² values were raised by up to 0.5 (e.g. from 0.2 to 0.7, example with the lowest R ²). A new training and application process for the RMs revealed further improvements by using a hierarchical agglomerative clustering algorithm to determine different day-types as additional (categorical) variables in the RM. The application of these improved RMs for outlier detection is demonstrated in three buildings.     

非对称双曲面线形离子阱的设计及性能研究

为提升离子阱质量分析器的分析性能,本文提出一种非对称双曲面线形离子阱结构,通过优化离子出射方向上x电极的单向拉伸距离Δr_a,引入合理的非对称射频电场,从而提高离子单向出射效率。利用SIMION和AXSIM模拟软件分析非对称双曲面线形离子阱的内部电场分布、离子运动轨迹及模拟质谱图。结果表明,在性能优化的对称双曲面线形离子阱结构的基础上,其中1个x电极单向拉伸Δr_a=0.8 mm时,通过优化AC频率和扫描速率等参数,非对称双曲面线形离子阱的离子单向出射率可达90%以上,同时m/z 609离子的质量分辨率超过5 100。经优化几何结构后的非对称双曲面线形离子阱可在保证高质量分辨率的情况下,大幅提高离子检测效率,这在小型化质谱仪的开发中具有显著的优势。     

A linear programming model for cash flow management in the Brazilian construction industry

A linear programming model has been developed for optimal cash flow management addressing specific cash flow issues related to the construction industry. These include typical financial transactions, possible delays on payments, use of available credit lines, effect of changing interest rates, and budget constraints that often occur in the construction industry. A small size project from the Brazilian construction industry is provided as a case study, aiming at evaluating the potential benefits from using the model. Different changes to the basic structure of the model allow and establish the consistency of the results. Alternative formulations are suggested to deal with uncertainties, longer planning horizons, and multiple subcontractors and suppliers. In addition to the tangible financial earnings derived from the optimization process, the simple structure of the model, as a network flow and corresponding equations, provides much visual insight concerning the relationships between the external inputs and the variables of the problem. Optimal results have yet to be achieved in a real life situation, but a better view of whole cash flow management is provided when using the model.     

The Ten‐Year Plan for the port of Antwerp (1956–1965): a linear city along the river

The Ten‐Year Plan for the port of Antwerp (1956–1965) funded the expansion of the port’s infrastructure over a 10‐year period. Strictly, a national government‐funded infrastructure programme for the construction of a set of canal docks, the programme laid the basis for a broader urbanization of the north‐eastern Antwerp metropolitan region. The importance of the operation lies primarily in its role as an instrument of urbanization rather than in the improvement of the transport and transshipment capacity of the port because it opened up a large territory to industrial settlement. The linear layout of the project along the Scheldt River led planners to conceive the further urbanization of the adjacent region on a linear city model, with satellite communities attached to the industrial and infrastructural strip. Compared with the contemporary Europoort plan for the port of Rotterdam, where several planning agencies implemented conflicting plans for functionally distinct infrastructures and the construction of a new town, the success of the Antwerp approach resides in the flexible and strategic implementation of the project as a co‐production between various authorities and private parties.     

拱脚水平弹性支承拱的屈曲分析

研究拱脚水平方向弹性支承拱的屈曲,提供弹性支承拱在3种荷载下的线性分析结果,分析拱的对称屈曲和反对称屈曲,得到对称屈曲和反对称屈曲的分界。最后提出临界轴力的计算公式及设计建议。