超声波测距的模糊控制泊车系统模型设计

设计了一种基于超声波测距的自动泊车系统模型。首先对小车运动模型进行分析,结合实际设计垂直、平行、斜行三种泊车模糊控制器,并且在Matlab的Simulink中分别进行仿真验证。采用超声波测距技术、视频采集技术等来获取周围环境数据,按照实际车辆和车库的大小,通过等比例缩放设计小车模型和车库模型,并把验证通过的模糊控制器转换为C代码,嵌入到飞思卡尔K60主控制板中进行自动泊车可行性测试。经测试,当模型车的航向角在-32°~+32°范围内时,实现了模型车在0.92倍标准大小模型车库内的自主泊车。     

γ‐Irradiation effects on the thermal and structural characteristics of modified,grafted polypropylene

The effects of both the degree of grafting and γ irradiation on the thermal stability and structural characteristic of polypropylene‐graft‐polyvinylpyrrolidone and polypropylene‐graft‐polyvinylpyrrolidone modified with α‐cyano‐δ‐(2‐thienyl) crotononitrile were investigated. The employed techniques were thermogravimetric analysis, differential thermogravimetry, and X‐ray diffraction. The thermal stability of various polymeric substrates was investigated through the determination of the degradation temperature and activation energy of degradation. The effects of different parameters on the structural characteristics of different films were investigated through the determination of possible changes in the degree of ordering of the polymeric substrates. The results revealed that the thermal stability of the trunk polymer, grafted polymer, and polymer modified by α‐cyano‐δ‐(2‐thienyl) crotononitrile increased progressively with an increasing degree of grafting. The increase was, however, more pronounced for the sample undergoing the lowest degree of grafting. The activation energy of the thermal degradation process remained almost unchanged, and this indicated that the degradation processes of the different films followed almost the same mechanism. The γ irradiation at a dose of 60 kGy of the sulfur‐treated polymeric films [i.e., the polymeric films treated with α‐cyano‐δ‐(2‐thienyl) crotononitrile] reduced their thermal stability. This conclusion was reached by the consideration of the changes observed in the pre‐exponential factor of the Arrhenius equation due to different chemical and γ‐irradiation treatments. The degree of ordering, evidenced by X‐ray diffraction measurements of the trunk polymer, grafted polymer, and modified polymer, suffered a significant drop. This drop was much more pronounced for the sulfur‐containing polymeric materials. The observed drop in the degree of ordering of the polymeric substrates was taken as a measure of the structure collapse due to a certain treatment (degree of grafting and sulfur inclusion). The γ irradiation of the sulfur‐containing polymeric materials greatly increased their degree of ordering, which reached a value greater than that measured for the trunk polymer. Therefore, it was concluded that the thermal stability increased as the degree of ordering decreased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 506–515, 2006     

185nmUV降解水中4-CP、4-NP和RhB的研究

本文以对氯苯酚（4-cP）、对硝基苯酚（4-NP）和罗丹明B（RhB）为模型有机物（以4-CP和4-NP为小分子模型有机物，以RhB为大分子模型有机物），分别研究了185nmUV对水中这3种模型有机物的降解规律、性能和效果．研究结果表明，185nmUV直接对水中4-CP、4-NP和RhB有很好的降解效果．研究内容包括：185nmUV降解模型有机物的浓度、TOC（Totalorganic carbon）浓度、185nmUV降解模型有机物过程中溶液pH及电导率变化、以及降解模型有机物过程中产生的无机离子等几个方面．     

Preparation and characterization of a proton‐exchange membrane by the radiation grafting of styrene onto polytetrafluoroethylene films

Radiation‐induced simultaneous grafting of styrene onto polytetrafluoroethylene (PTFE) films and the subsequent sulfonation in the chlorosulfonic acid/dichloroethane were investigated. The effects of the main radiation grafting conditions, such as the type of solvents, irradiation dose, dose rate, the styrene concentrations, etc., on the degree of grafting (DOG) were studied. To elucidate the influence of both the grafting and sulfonation conditions on the properties of the PTFE‐g‐polystyrene‐sulfonic acid (PSSA) membranes, the sulfonation conditions, including the sulfonation temperature and the concentration of the ClSO₃H with respect to the DOG, were systematically evaluated. The grafted and sulfonated membranes were characterized by FTIR–ATR spectra, ion‐exchange capacity (IEC), water uptake, thickness measurement, etc. The as‐prepared PTFE‐g‐PSSA membranes in this work showed a good combination of a high IEC (0.85–2.75 meq g^?1), acceptable water uptake (8.86–56.9 wt %), low thickness, and volume expansion and/or contraction. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1415–1428, 2006     

Molecular motions of non-crystalline poly(aryl ether-ether-ketone) PEEK and influence of elecron beam irradiation

The dynamic mechanical relaxation of non-crystalline poly(aryl ether-ether-ketone) PEEK and the one irradiated with electron beam were studied. The three distinct γ, β, α′ relaxation maxima were observed in unirradiated PEEK from low to high temperature. It was revealed from the study on the irradiation effects that three different molecular processes are overlapped in γ relaxation peak, i.e., molecular motion of water bound to main chain (peak temperature; at ?100°C), local motion of main chain (at ?80°C), and local mode of the aligned and/or oriented moiety (at ?40°C). The β relaxation connected with the glass transition occurred at 150°C and it shifted to higher temperature by irradiation. The α′ relaxation which can be attributed to rearrangement of molecular chain due to crystallization was observed in unirradiated PEEK ～ 180°C and its magnitude decreased with the increase in irradiation dose. This effect indicates the formation of structures inhibiting crystallization such as crosslinking and/or short branching during irradiation. A new relaxation, β′, appeared in the temperature range of 40° to 100°C by irradiation and its magnitude increased with dose. This relaxation was attributed to rearrangement of molecular chain from loosened packing around chain ends, which were introduced into the non-crystalline region by chain scission under irradiation, to more rigid molecular packing, From these observations, we proposed that deterioration in mechanical properties of non-crystalline PEEK by high energy electron beam was brought about not only by chain scission but structural changes such as crosslinking and/or branching in the main chain.     

Preparation of rechargeable lithium batteries with poly(methyl methacrylate) based gel polymer electrolyte by <Emphasis Type="Italic">in situ</Emphasis>γ-ray irradiation-induced polymerization

An admixture of commercial liquid electrolyte (LB302, 1 M solution of LiPF₆ in 1:1 EC/DEC) and methyl methacrylate (MMA) was enclosed in CR2032 cells. The assembled cells were then -ray-irradiated using configurations of half cells and full cells. Through this in situ irradiation polymerization process, we obtained rechargeable lithium ion cells with poly(methyl methacrylate) (PMMA) based gel polymer electrolytes (GPE). Galvanostatic cycling, AC impedance spectroscopy, and cyclic voltammetry were employed to investigate the electrochemical properties of the cells and the gel polymer electrolyte. This PMMA-based gel polymer electrolyte was found to exhibit a high ionic conductivity (at least 10^–3 S cm^–1) at room temperature. Due to a significant increase in the charge transfer resistance between the GPE and the cathode, the cell impedance of a PMMA-based lithium ion cell is greater than that of a liquid-electrolyte-based cell. The discharge capacity of a LiNi_0.8Co_0.2O₂/GPE/graphite is approximately 145 mAh g^–1 for the first cycle and decreases to123 mAh g^–1 after 20 cycles. In addition, a large initial cell impedance (LICI) was observed in the irradiated positive half cell. In this paper, we propose a possible mechanism related to the detachment of the PMMA layer from the lithium electrode. This detachment of the PMMA layer from the lithium electrode has not been explicitly discussed previously.     

新型非侵入式超声物位检测方法研究

在石化行业,存在大量装载颗粒物料的反应器和容器,其料位的实时准确检测对于生产过程的控制和优化具有非常重要的作用.本文利用超声辐射阻尼原理,揭示了料仓中物料料位的高低与固体介质表面传播的超声振动吸收的定量关系,建立了颗粒状物料料位高度的关联公式.该公式可以定量地描述物料位高度与超声振动能量的衰减、颗粒物理性质和振动传递介质的关系,具有较高的精度.同时,通过成纵向排列的一系列接收探头所接收到的脉冲超声波能量的峰能量比,可以确定出储罐内液位的高度,其检测精度与接收探头的数量成正比.研究结果表明,无论是颗粒料位还是液体料位,都能利用基于超声辐射阻尼原理研制的浙江大学联合化学反应工程研究所UGAS-05声检测系统实现料位的实时在线检测.     

硫酸盐腐蚀粉煤灰混凝土后强度超声检测评定

为进一步研究混凝土受硫酸盐侵蚀的机理,以粉煤灰混凝土为研究对象,在高浓度硫酸盐溶液中进行加速腐蚀,并结合受硫酸盐腐蚀后混凝土强度变化规律,采用超声平测法对受腐蚀混凝土进行检测．研究结果表明,超声平测声速与损伤度之间有较好的回归关系．在此基础上,建立了腐蚀混凝土强度与声速之间的关系模型．     

Fabricated and friction test anisotropy material of ultrasonic motor

The twisters for composed of anisotropic material were designed and manufactured.And two kinds of directional-composites were made:one was fiber direction vertical with frictional interface and another was parallel with frictional interface and moving direction.By varying the proportions of epoxy resin and fiber and arranging the orientations of fiber,the composites anisotropy along longitudinal and circumferential were got.Using density measurement,the mass fraction of resin and fiber were calculated.According to composite meso-scopic mechanics,the elasticity constants of composite were analyzed and calculated.The composite different thicknesses were sliced,and attach to the rotor,then the load characteristics,no-load speed,stop load of ultrasonic motor(USM)were test.The output properties of USM with 0.6 mm thickness composite were superior.The effect of friction material on ultrasonic motor was analyzed.Elastic modulus,thickness and micro-morphology of material are main factors which affect characteristics of ultrasonic motor.     

EPS颗粒级配对EPS混凝土力学性能的影响

聚苯乙烯泡沫塑料(EPS)混凝土是一种质轻而具有良好力学性能的新型建材.EPS混凝土的力学性能与混凝土基质强度以及EPS颗粒粒径有关.通过试验比较不同EPS颗粒级配,不同EPS粒径大小的EPS混凝土的抗压、抗拉、抗折强度,提出了EPS混凝土抗压强度关系表达式,并用超声检测的方法测试了EPS混凝土的受压破坏过程.研究表明,EPS混凝土的力学性能与颗粒级配及颗粒含量有关,超声检测的方法能反映EPS混凝土的损伤破坏过程.