“低碳经济”理念下的中小城市住宅建设与发展对策研究--以株洲市为例

本文通过对目前中小城市（以株洲市为例）楼市的调查与研究,发现中小城市的楼市趋向大面积户型住宅建设。本文从“低碳经济”的理念出发,提出了应在中小城市中应大力发展中小户型住宅的建议。     

我国可持续社区评估体系优化策略研究*

评估体系的发展对可持续社区的发展有着很重要的意义,是可持续社区进行规划建设的标尺.英国可持续社区评估体系BREEAM Communities在欧洲有较为广泛的应用,本文以该体系和《中国生态住区技术评估手册》作为研究对象,通过对比二者在体系结构、指标内容及评估方法上的异同,抽取出BREEAM Communities评估体系的适用性内容,对我国可持续社区评估体系的评估流程、评估引导原则、评估内容增设、评估指标体系完善等方面提出适宜性优化策略.     

福州港松下港区牛头湾作业区航道平面方案研究

福州港松下港区牛头湾作业区7万吨级1#、2#和3#泊位分别于2007年、2009年及2012年建成投产至今,每年11月至翌年3月期间受风浪影响,大型船舶靠、离码头难度大、系泊码头作业泊稳条件差。为保障船舶靠、离泊和系泊作业安全,业主单位拟建设防波堤二期工程,与已建防波堤一期工程形成环抱式防波堤。本文根据防波堤布置初步方案,对港区进港航道进行平面布置比选,并提出防波堤、航道布置优化方案,节省了工程投资。经波浪数值模拟和潮流数值模拟验证,航道布置方案可满足船舶安全通航要求,优化后防波堤仍能有效减小码头前沿波高,满足码头泊稳条件和实际作业要求。     

多关节测量臂的小生境混沌优化校准

多关节测量臂是一种便携式的坐标测量设备,它由一系列的旋转关节组成。为了提高多关节测量臂的测量精度和可重复性水平,必须对其运动学参数进行校准。首先,利用小生境的混沌优化算法提出了一种新的运动学校准方法以及一种混合目标的运动学校准函数,它考虑了诸如单点测量实验、容积性测量实验等多种性能测量实验的实验结果,然后,采用Levenberg Marquardt(L-M)算法和小生境混沌优化算法应用于运动学参数校准。小生境混沌优化算法显示出了优于L-M算法的性能。实验结果表明:使用NCOA算法校准后,测量误差的标准差始终优于LMA算法,并且校准前后多关节测量臂的测量精度提高了40倍。采用L-M算法和小生境混沌优化算法应用于运动学参数校准。小生境混沌优化算法显示出了优于L-M算法的性能。     

子母弹抛撒参数优化与抛撒/盲区半径误差分析

以抛撒半径和抛撒盲区作为优化目标,以母弹抛撒时的高度、速度、当地弹道倾角、子弹最大抛撒速度和子弹最小抛撒速度等抛撒参数为优化变量,研究了子母弹抛撒参数优化设计方法.以该优化方法计算了一个算例,利用计算得到的偏导数进行了抛撒半径和盲区半径的误差分析.     

多轴越野车辆轴间刚度和阻尼的最优匹配

为提高多轴越野车的行驶平顺性,建立了8×8越野车半车模型的六自由度动力学方程,求解对第一轴路面输入的传递函数.以提高行驶平顺性为目的确立目标函数,应用遗传算法对各轴间的悬架刚度和阻尼进行匹配优化,将优化前后的结果进行对比分析,优化后的悬架刚度和阻尼有效提高了多轴越野车辆的行驶平顺性.     

Feasibility study and performance assessment for the integration of a steam-injected gas turbine and thermal desalination system

This study proposes a systematic approach for retrofitting a steam-injection gas turbine (SIGT) with a multi-effect thermal vapor compression (METVC) desalination system. The retrofitted unit's product cost of the fresh water (RUPC) was used as a performance criterion, which comprises the thermodynamic, economic, and environmental attributes when calculating the total annual cost of the SIGT–METVC system. For the feasibility study of retrofitting the SIGT plant with the METVC desalination system, the effects of two key parameters were analyzed using response surface methodology (RSM) based on a central composite design (CCD): the steam air ratio (SR) and the temperature difference between the effects of the METVC system (?T_METVC) on the fresh water production (Q_freshwater) and the net power generation (W_net) of the SIGT–METVC system. Multi-objective optimization (MOO) which minimizes the modified total annual cost (MTAC) and maximizes the fresh water flow rate was performed to optimize the RUPC of the SIGT–METVC system. The best Pareto optimal solution showed that the SIGT–METVC system with five effects is the best one among the systems with 4–6 effects. This system under optimal operating conditions can save 21.07% and 9.54% of the RUPC, compared to the systems with four and six effects, respectively.     

The Optimization of the Production of Methyl Esters from Corn Oil Using Barium Hydroxide as a Heterogeneous Catalyst

In recent years, vegetable oils, as renewable raw materials, became a promising feedstock for chemicals and biodiesel production. The main products derived from oils are esters of fatty acids, especially methyl esters, obtained by their transesterification with methanol, in presence of acid or alkaline catalysts. The use of such catalysts implies the need for washing operations, which leads to environmental pollution. In the present paper, the response surface methodology based on a central composite design, has been developed to optimize the process of transesterification of corn oil. Ba(OH)₂ in presence of diethyl ether was used as catalyst. A quadratic polynomial equation was obtained. It correlates the reaction parameters [methanol/oil molar ratio (x _r), reaction time (x _t) and catalyst concentration (x _c)] with methyl esters yield. Analysis of variance analysis showed that only methanol/oil molar ratio and catalyst concentration have had the most significant influences on the conversion. The maximum methyl esters yield was obtained using the following optimum parameters: methanol/corn oil ratio of 11.32, reaction time of 118 min and catalyst concentration of 3.6 wt%.     

Using surrogate models for efficient optimization of simulated moving bed chromatography

A new approach of using computationally cheap surrogate models for efficient optimization of simulated moving bed (SMB) chromatography is presented. Two different types of surrogate models are developed to replace the detailed but expensive full-order SMB model for optimization purposes. The first type of surrogate is built through a coarse spatial discretization of the first-principles process model. The second one falls into the category of reduced-order modeling. The proper orthogonal decomposition (POD) method is employed to derive cost-efficient reduced-order models (ROMs) for the SMB process. The trust-region optimization framework is proposed to implement an efficient and reliable management of both types of surrogates. The framework restricts the amount of optimization performed with one surrogate and provides an adaptive model update mechanism during the course of optimization. The convergence to an optimum of the original optimization problem can be guaranteed with the help of this model management method. The potential of the new surrogate-based solution algorithm is evaluated by examining a separation problem characterized by nonlinear bi-Langmuir adsorption isotherms. By addressing the feed throughput maximization problem, the performance of each surrogate is compared to that of the standard full-order model based approach in terms of solution accuracy, CPU time and number of iterations. The quantitative results prove that the proposed scheme not only converges to the optimum obtained with the full-order system, but also provides significant computational advantages.     

基于遗传算法的多级主压阀动态特性优化

多级主调压阀作为自动变速器液压控制系统的关键元件,其动态特性直接影响系统的快速性、稳定性和控制精度。在对阀进行结构参数优化时,先凭借经验对参数逐个调整再通过试验验证的方法,效率低且不能保证阀的性能最优。根据多级主压阀工作原理建立了多级主压阀数学模型;搭建多级主压阀Simulink仿真模型,通过分析多级主调压阀各结构参数对阀入口压力动态响应特性的影响,选取弹簧刚度、弹簧预压缩量和阻尼孔直径作为待优化变量;利用MATLAB优化工具箱中提供的遗传算法与Simulink结合对多级主调压阀的动态性能进行优化,并搭建试验台进行试验验证。仿真和试验结果表明：优化后多级主调压阀静态特性良好,负载流量突增时主压压力降低现象得到了改善,响应时间短,动态性能好。