基于人工神经网络的沥青路面水膜厚度预测（英文）

为了研究多因素影响下沥青路面水膜厚度的变化,结合基于水动力学理论的二维浅水方程,提出一种利用人工神经网络(ANN)预测沥青路面水膜厚度的方法.多因素包括降雨强度、路面宽度、路面横坡、路面纵坡和路面粗糙系数.二维水动力仿真模型经过实测数据验证并根据沈山高速公路工程设计方案仿真得到有限数量的训练数据用于沥青路面水膜厚度的预测,进而分析了多因素对水膜厚度在路面分布的影响.经过18组数据的验证,人工神经网络模型预测精度可达0.991.预测结果表明:水膜厚度从中央分隔带向道路边缘逐渐增加,降雨强度对水膜厚度的变化有明显影响.在路面宽度20 m,降雨强度30 mm/h的条件下,路面内侧车道内的水膜厚度低于10 mm,外侧车道的水膜厚度为20 mm.受训练样本数量的影响,预测结果存在一定的波动,但与现行规范和理论计算值相比,人工神经网络模型能够更好地描述沥青路面水膜的宏观分布特性.     

两相质子交换膜燃料电池工作性能优化

该文建立了质子交换膜燃料电池二维稳态等温多相模型，在多孔介质中，利用MaxwellStefan多组分扩散方程与相变方程进行数值计算，探讨了阴极多孔电极与质子膜中的水分布，分析了操作条件和结构对燃料电池输出性能的影响.数值结果表明，液态水含量具有明显的空间分布，受结构和操作条件的影响明显，适当降低阴极进气湿度、提升进气压力和使用疏水性材料有利于电池性能达到最优.基于气液两相模型的燃料电池的极化曲线与实验数据具有很好的一致性，表明了模型的有效性，采用优化的1 mm宽流道可以有效改善阴极催化层中水和氧气浓度分布的均匀性，从而提高电池性能.     

基于全面质量管理的研究生教育质量管理

基于全面质量管理理念,建立了研究生教育质量管理体系模型,从管理职责、资源管理、产品实现和测量分析改进四个方面对研究生教育质量管理体系模型的构成内涵进行了分析.     

纤维长度与水膜厚度对玄武岩纤维增强砂浆新拌性能的影响研究（英文）

目的:纤维增强水泥基材料新拌性能的关键影响因素仍有待探明。本文以玄武岩纤维增强砂浆为研究对象,旨在研究纤维长度与水膜厚度对砂浆新拌性能的综合影响,进而推动水泥基材料流变学"膜厚度与纤维因子理论"的发展。创新点:1.通过试验分析,发现水膜厚度与纤维长度是砂浆新拌性能的重要影响因素;2.通过回归分析,建立玄武岩纤维增强砂浆新拌性能的预测模型。方法:1.通过调整纤维长度和水灰比,制备20组试验砂浆,并对其进行各项新拌性能试验(表4);2.采用堆积密实度湿测法,对砂浆固体组分的堆积密实度进行测定(图3),并计算水膜厚度(图4);3.通过回归分析方法,系统分析水膜厚度和纤维长度对砂浆各项新拌性能的综合影响,并建立玄武岩纤维增强砂浆新拌性能的预测模型(图5～9)。结论:1.水膜厚度是影响玄武岩纤维增强砂浆新拌性能的主要因素;2.纤维长度也对各项新拌性能有重要影响:纤维长度的增加,会降低砂浆的堆积密实度与水膜厚度,降低流动性和粘附性,但会提升粘聚性;3.通过回归分析,建立了基于纤维长度和水膜厚度的玄武岩纤维增强砂浆新拌性能预测模型。     

除尘器安装调试技术对除尘器性能的影响

除尘器的安装调试技术是影响其收尘性能的重要因素.本文从气流均布装置安装质量、异极间距、阴阳极振打装置、壳体密封和保温、及高压供电装置等五个方面对除尘器性能的影响进行分析,以求实现静电除尘器的长效运行.     

钢筋混凝土在使用中与外部环境发生化学作用及其防护

主要从化学的角度对钢筋混凝土在使用过程中与外部环境发生作用等情况进行了分析 ,结果发现 :水、酸 (酸性液体 )、阴阳极作用等均可导致钢筋混凝土侵蚀而破损 ,从而探讨提高钢筋混凝土的抗蚀性 ,延长其使用寿命的措施     

水热处理对热塑性豆类淀粉结构和性能的影响

用流延法制备了甘油含量一定不同温度水热处理的热塑性豆类淀粉膜材料,采用粘度、X衍射分析（XRD）、差示扫描量热分析（DSC）、扫描电镜（SEM）和力学测试研究了不同温度水热处理对豆类淀粉热塑性材料的结构和性能的影响。粘度测试显示水热处理后豆类淀粉溶液的粘度增大;X衍射分析（XRD）、差示扫描量热分析（DSC）和扫描电镜（SEM）显示,豆类淀粉经过水热处理后,结构发生了很大变化;力学性能测试表明,110℃水热处理过的淀粉膜（甘油含量为30%）的拉伸强度为11．78MPa,断裂伸长率为27．24％,与相同甘油含量非水热处理的豆类淀粉膜相比．其拉伸强度提高了5．75MPa,断裂伸长率提高了3．32％。     

浑水膜缝入渗规律试验研究

利用大田入渗试验资料，分析了清水情况下膜缝宽度与膜缝入渗水量之间的关系，建立了清水的膜缝入渗模型；同时对不同含沙率的浑水对膜缝入渗水量的影响进行分析，建立了浑水膜缝入渗的入渗模型。     

本体理论视角下高职网络课程知识管理模型的构建

本文分析了当前高职精品网络课程在知识管理中存在的问题,提出了在本体理论视角下构建课程知识管理模型的设计思想和建模步骤,并以《C程序设计》课程为案例,建立了基于本体的知识管理模型,同时分析了课程知识语义检索机制的实现方法。     

中空纤维膜脱氧过程中Dean涡强化传质研究（英文）

目的:在螺旋中空纤维膜脱氧过程中引入了Dean涡,与线型中空纤维膜脱氧过程相比传质速率显著提升。本文旨在建立新的螺旋中空纤维膜脱氧过程传质模型,探讨管程流体雷诺数、中空纤维膜结构参数、壳程真空度和操作温度对Dean涡强化传质效果的影响,并优化螺旋中空纤维膜脱氧过程操作参数。创新点:1.建立新的螺旋中空纤维膜脱氧过程传质模型;2.该传质模型可以应用于任何螺旋中空纤维膜气-液过程的传质行为描述。方法:1.实验研究管程流体雷诺数、中空纤维膜结构参数、壳程真空度和操作温度对Dean涡强化传质效果的影响,并与线型中空纤维膜传质进行对比。2.利用螺旋坐标系下的质量连续性方程以及Dean涡的摄动解描述管程溶质的传质行为;利用改进的尘气模型描述膜孔道内多组份气体的扩散行为;耦合建立新的螺旋中空纤维膜脱氧过程传质模型,并与实验结果进行比较。3.模拟脱氧过程的氧、氮、水三种组分的浓度分布,优化螺旋中空纤维膜脱氧过程的膜结构参数和操作参数。结论:1.实验和模拟结果均证实Dean涡可以有效提升脱氧传质速率,最大传质增强因子为2.2。2. Dean涡主要受到管程雷诺数和中空纤维膜曲率的影响;当管程雷诺数较大时,中空纤维膜即使存在很小的曲率,传质的速率也有显著的提升。     

Dynamic modeling and simulation test of a 60 kW PEMFC generation system

In this paper, a 60 kW proton exchange membrane fuel cell (PEMFC) generation system is modeled in order to design the system parameters and investigate the static and dynamic characteristics for control purposes. To achieve an overall system model, the system is divided into five modules: the PEMFC stack (anode and cathode flows, membrane hydration, and stack voltage and power), cathode air supply (air compressor, supply manifold, cooler, and humidifier), anode fuel supply (hydrogen valve and humidifier), cathode exhaust exit (exit manifold and water return), and power conditioning (DC/DC and DC/AC) modules. Using a combination of empirical and physical modeling techniques, the model is developed to set the operation conditions of current, temperature, and cathode and anode gas flows and pressures, which have major impacts on system performance. The current model is based on a 60 kW PEMFC power plant designed for residential applications and takes account of the electrochemical and thermal aspects of chemical reactions within the stack as well as flows of reactants across the system. The simulation tests show that the system model can represent the static and dynamic characteristics of a 60 kW PEMFC generation system, which is mathematically simple for system parameters and control designs.     

Control design of 60 kW PEMFC generation system for residential applications

This paper presented a control design methodology for a proton exchange membrane fuel cell （PEMFC） generation system for residential applications. The dynamic behavior of the generation system is complex in such applications. A compre- hensive control design is very important for achieving a steady system operation and efficiency. The control strategy for a 60 kW generation system was proposed and tested based on the system dynamic model. A two-variable single neuron proportional-integral （PI） decoupling controller was developed for anode pressure and humidity by adjusting the hydrogen flow and water injection. A similar controller was developed for cathode pressure and humidity by adjusting the exhaust flow and water injection. The desired oxygen excess ratio was kept by a feedback controller based on the load current. An optimal seeking con- troller was used to trace the unique optimal power point. Two negative feedback controllers were used to provide AC power and a suitable voltage for residential loads by a power conditioning unit. Control simulation tests showed that 60 kW PEMFC generation system responded well for computer-simulated step changes in the load power demand. This control methodology for a 60 kW PEMFC generation system would be a competitive solution for system level designs such as parameter design, performance analysis, and online optimization.     

Hybrid intelligent PID control design for PEMFC anode system

Control design is important for proton exchange membrane fuel cell （PEMFC） generator. This work researched the anode system ofa 60-kW PEMFC generator. Both anode pressure and humidity must be maintained at ideal levels during steady operation. In view of characteristics and requirements of the system, a hybrid intelligent PID controller is designed specifically based on dynamic simulation. A single neuron PI controller is used for anode humidity by adjusting the water injection to the hydrogen cell. Another incremental PID controller, based on the diagonal recurrent neural network （DRNN） dynamic identification, is used to control anode pressure to be more stable and exact by adjusting the hydrogen flow rate. This control strategy can avoid the coupling problem of the PEMFC and achieve a more adaptive ability. Simulation results showed that the control strategy can maintain both anode humidity and pressure at ideal levels regardless of variable load, nonlinear dynamic and coupling characteristics of the system. This work will give some guides for further control design and applications of the total PEMFC generator.     

PEMFC分散发电系统的压力控制研究

NomenclatureA-area ( m2)Dw-membrane water diffusivity ( m2/s)F-=96 487I-current (A)M-molecule mass (kg/mol)T-temperature (K)W-mass flowrate (kg/s)cw-water concentration in membrane ( mol/m3)m-mass (kg)n-cell numbernd-electro-osmotic drag coefficientp-pres…     

Modelling and control PEMFC using fuzzy neural networks

INTRODUCTION With worldwide increase of air pollution and the environmental consciousness of governments,people have to look for new resources to mitigate the energy crisis and improve the present environmental status(Baschuk and Li,2000;Rowe and Li,2001).Fuel cells are highly efficient and environmentally clean electricity generators(Berning et al.,2002)that convert the chemical energy of a gaseous fuel directly into electrical energy and play an important role in solving the energy pro…     

New hybrid model of proton exchange membrane fuel cell

Model and simulation are good tools for design optimization of fuel cell systems. This paper proposes a new hybrid model of proton exchange membrane fuel cell (PEMFC). The hybrid model includes physical component and black-box com-ponent. The physical component represents the well-known part of PEMFC, while artificial neural network (ANN) component estimates the poorly known part of PEMFC. The ANN model can compensate the performance of the physical model. This hybrid model is implemented on Matlab/Simulink software. The hybrid model shows better accuracy than that of the physical model and ANN model. Simulation results suggest that the hybrid model can be used as a suitable and accurate model for PEMFC.     

Nonlinear modeling of PEMFC based on neural networks identification

INTRODUCTION With worldwide increase of air pollution and the environmental consciousness of governments, people have to look for new resources to mitigate the energy crisis and improve the present environmental status (Ferng et al., 2004; Rowe and Li, 2001). Fuel cells are highly efficient and environmentally clean electrical generators (Mann et al., 2000) that convert the chemical energy of a gaseous fuel directly into elec-tricity energy and play an important role in solving the prob…     

Adaptive inverse control of air supply flow for proton exchange membrane fuel cell systems

To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control (AIC) strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell (PEMFC) system in this paper.The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network (RFNN) is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.     

基于BP神经网络的PEMFC电堆的静态热系统建模

质子交换膜燃料电池(PEMFC)电堆的温度是影响燃料电池性能的关键因素之一,建立电堆的热系统模型是准确控制电堆温度的基础。文章中利用反向传播(BP)神经网络对质子交换膜燃料电池的静态热系统进行建模。仿真结果表明,神经网络建模方法能够较好地拟合数据。     

Operation Characteristics of Treating Surface Water with Polyvinylchloride Hollow Fiber Ultrafiltration Membrane

Ultrafiltration (UF) technique is prospective asalternative for conventional processes such as coagula-tion, flocculation, sedimentation and/or flotation,rapid and slowsand filtration[1]. Recentdevelopmentsin reducing energy consumption by (semi) dead-endfiltration and prevention of membrane fouling by back-washing (combined with chemicals), make UF moreand more an interestingoption forthe treatmentof sur-face water on a large scale[2]. At present, UF full-scale applications are evenlyspread…