车用增压器涡轮脉冲进气非稳态特性

对某增压器涡轮工作在对应于发动机标定工况下的非稳态特性进行了试验研究,发现涡轮的非稳态特性与稳态特性存在着比较大的偏离,非稳态特性围绕着稳态特性形成了一个"环状"的特性圈.从循环平均的角度分析了脉冲频率、膨胀比和转速对涡轮流量特性和效率特性的影响.根据试验结果进一步分析了"环状"特性圈形成的机理,指出涡轮在脉冲进气条件下非稳态特性与稳态特性的偏离主要是由于涡轮内的"容积效应"引起的.     

全基本电机的通用特性方程

本文首先提出了“全基本电机的通用特性方程”,在此基础上导出了直流电机的通用特性方程、同步电机的通用特性方程和异步电机的通用特性方程;利用这三个通用特性方程,并结合每种基本电机的特性,即可推导出所有基本电机的许多特性方程,这就解决了所有基本电机的非线性定量化问题。     

内燃机特性曲线的数值分析及自动化处理

本文对内燃机性能特性曲线的数值方法进行了分析,提出了适合内燃机性能特性曲线处理的数学模型及其处理方法。采用微机自动处理内燃机特性曲线,实现了内燃机负荷特性曲线、速度特性曲线、万有特性曲线的自动化处理。     

电力负荷特性统计度量新方法研究

电力负荷特性指标是电力负荷变化特征的数量表现,是进行电力负荷特性统计分析的基础。目前负荷特性指标主要是从技术、物理概念出发,统计上采用最大、最小、平均与极差几个统计量来描述,信息不甚充分。在电力规划、设备运行等方面,我们需要从技术与效益双角度,着眼负荷出现的概率进行特性分析,这就需要我们补充新的负荷特性描述、分析方法,进行负荷概率特性的分析。文章从负荷的概率特性、负荷特性指数以及负荷特性的综合评价三个方面研究了度量电力负荷特性的新方法。     

论电力负荷特性指数

基于现存指标体系的局限,提出构造负荷特性指数,完善电力负荷特性的统计度量,并具体讨论了负荷特性互补指数与负荷特性综合评价指数构造问题,前者旨在对联网相关地区负荷特性的互补性作一个科学度量,后者旨在以一个综合指数对负荷特性作一个整体上的描述.     

数控伺服系统间隙特性的仿真与分析

为了探求数控机床的伺服系统间隙特性对加工误差的影响,文中对间隙特性进行了分析,文中提出了其数学表达式,建立了含有间隙特性的两轴联动数控伺服系统的数学模型.以圆弧插补结果作为进给指令,进行了仿真.通过比较和分析伺服系统各个节点响应特性,验证了间隙特性表达式及伺服系统的数学模型.结果表明:间隙特性表达式能准确反映间隙特性规律,能描述在伺服系统含有间隙特性时,圆形加工件的轮廓特征和误差分布的机理,可以作为实际加工中误差预测的理论依据.     

“车适应人”线控汽车理想特性参考模型神经网络建模

针对线控汽车上通过对各个线控系统地集成控制以实现个性化理想汽车动力学特性即"车适应人"问题,进行了线控汽车理想特性参考模型神经网络建模研究。对驾驶员特性进行了初步分类,给出了汽车理想特性控制原理;设计了汽车驾驶模拟器实验,进行了理想特性参考模型神经网络建模;对模型精度、特性反映程度和实时性进行了实验验证。研究表明,所建立的理想特性参考模型精度高、实时性好,能反映不同驾驶特性,建模方法具有可行性。     

管道系统中集中流容时均特性的影响因素

集中流容是管道系统中的重要装置,它的特性对系统正常安全运行至关重要.分析了管道系统中集中流容时均特性的影响因素,并结合实验研究给出了以水箱为代表的集中流容时均特性随管系特性、流容固有特性和工作过程的变化规律,为集中流容时均特性研究提供了一个范例.     

大豆多肽的功能性质及应用前景

大豆多肽是大豆蛋白质的水解产物,具有优良的物理特性、营养特性、加工特性和生理功能,在食品、医药保健品和饲料添加剂中得到了广泛的应用。综述了大豆多肽的物理特性、营养特性、加工特性、生理功能和研究现状,并对大豆多肽在研究和应用中的主要问题进行了阐述。     

企业议价能力的影响因素分析：浙江产品实证

本文将议价能力的影响因素分为三大类：企业特性、市场特性和消费者特性。根据浙江省面向工业企业问卷调查数据,以层次分析和回归分析为定量研究方法,研究这三大影响因素和议价能力之间的关系,主要结论有：企业特性、市场特性和消费者特性对企业议价能力有着显著的正向影响。     

Effect of Pb Substitution on the Microstructure and Ferroelectric Properties of Ba0.7Sr0.3TiO3 Ceramic

Ferroelectric Ba0.7Sr0.3TiO3(BST) and partially Pb2+ substituted for Ba2+ ceramics (Bao.7-xPbx)Sr0.3TiO3 (x=0.1-0.4,BPST) were prepared by using conventional solid-reaction method.XRD analysis shows that the samples microstructure changes from cubic phase to tetragonal one with the Pb2+ content increasing.ESEM analysis shows that the Pb2+ substituted samples have a denser and more uniform surface morphology than that of pure BST.Measured electrical properties suggest that the Pb2+ substitution for Ba2+ in the BST system enhances the ferroelectric performance obviously when x=0.2.In addition,the substitution increases the samples Curie temperature (Tc).(Ba0.5Pb0.2)Sr0.3TiO3 ceramic has good ferroelectric properties measured at a maximal electric field of 30 kV/cm under the condition of room temperature.The corresponding saturated polarization (Ps),remnant polarization (Pr) and coercive field (Ec) is respectively 15.687 μC/cm2,8.100μ C/cm2 and 6.611 kV/cm.The measured Tc of (Ba0.5Pb0.2)Sr0.3TiO3 is 117 ℃.     

(Ba,Pb)TiO_3系高温PTC半导体材料研究

本文研究了含铅高温PTC半导体陶瓷材料的性能和工艺特点。采用快速烧结法获得了性能优良的(Ba,Pb)TiO_3系半导体材料。     

STUDY ON COMPLEX IMPEDANCE SPECTROSCOPY OF CU-IMPLANTED SEMICONDUCTING (BaO.72PbO.28)TiO3 CERAMICS

The ac impedance of Nb-doped semicon-ducting (Bao.72Pbo.28)TiO3 ceramics implanted with copper ions(200keV,6X1015 and 1X1017 ions/cm2) in the temperature range 25-320C and the frequency range 10 Hz -13MHz was measured. According to the change of impedance spectroscopy and the equivalent circuit model of semiconducting(Ba, Pb)TiO3 ceramics, the dependence of resistance of bulk and grain-boundary on temperature was analyzed. The results show that relatively low dose must be used to increase the magnitude of the positive temperature coeffieient of resistance(PTCR)effects in the cermmics. In addition,the effects of Cu ion implantation on the PTCR behavior of the ceramics was studied by raststance-tempera-ture measurement.     

Influence of Excessive SiO2 or TiO2 on the Electric Properties of

The dependence of electrical properties of Ba0.92Ca0.08TiO3 PTCceramics on the SiO2 or TiO2 content was studied. The dependence of room temperature resistivity on the SiO2 content was determined by the variation of the microstructure of Ba0.92Ca0.08TiO3 PTC ceramics. It was shown that a small amount of excessive TiO2 (2mol%) added could increase the dielectric constant of materials, and it results in a reducing of the potential height (e*φ) of grain boundary. Thus, samples with particularly low room temperature resistivity were obtained. The relationship of PTC effect with the TiO2 content was also discussed by using the chemistry defect theory. The inferior PTC effect caused by excessive TiO2 may be concerned with the behavior of oxygen vacancies in the grains of ceramics.     

受主杂质Mn对（Ba,Pb）TiO3系高温PTC热敏陶瓷的影响

本文研究了(Ba,Pb)TiO_3系高温PTC半导体陶瓷中半导化与其烧结工艺、铅空位、钡空位和施、受主杂质等相互之间的关系。着重分析讨论了引入受主杂质Mn对材料的半导化的影响,并采用复合缺陷模型自洽地解释了实验现象。     

Struchre and Electrical Properties of (Na0.5Bi0.5)0.94Ba0.06TiO3 Ceramic with 0.5 wt% of MnO

The structure and electrical properties of(Na0.5Bi0.5)0.94Ba0.06TiO3 ceramic doped with 0.5 wt% of MnO were investigated in comparison with those of(Na0.5Bi0.5)0.94Ba0.06TiO3 ceramic.It was ascertained that the MnO addition did not cause remarkable change in crystal structure and microstructure.The MnO addition mainly displayed a hard effect on the electrical properties,an increase of coercive field(Ec)and mechanical quality factor(Qm)together with a decrease of dielectric constant(?r)and piezoelectric constant(d33).An enhancement of electromechanical coupling factor(kp)with the MnO addition was obtained too.An essential relation between the piezoelectric properties and ferroelectric nature of the ceramics was detected.It was found that the piezoelectric properties of the ceramics highly depended on the corporative contribution of remanent polarization(Pr)and coercive field.     

Preparation and densification of BaTiO3 nanopowder by sol—gel autoigniting synthesis

Autoigniting synthesis of gel from Ba(NO3)2,TiO(NO3)2 and C6H8O7.H2O aqueous solution was investigated at an initial temperature of 600℃ and tetragonal BaTiO3 nanopowder with particle size of 80nm was prepared.It is indicated that the specific surface area of the combustion product before and after calcination is 14.74m^2/g and 12.49m^2/g,respectively.The combustion wave is composed of solid phase reaction zone and gaseous phase flame reaction zone.The combustion flame temperature is 1123K derived from thermo couple measurement.The characteristics and densification behavior of the sol-gel autoigniting synthesized BaTiO3 nanopowder were in vestigated.     

无铅压电陶瓷钛酸铋钠(NBT)的掺杂改性研究

在无铅压电陶瓷（Na0.5Bi0.5)TiO3(NBT)中加入BaTiO3(BT)及微量Sb2O3，对其进行掺杂改性研究。通过研究不同加入量对NBT性能的影响，得到了较佳性能的材料配方为（Na0.5Bi0.5)0.92Ba0.08TiO3 ySb2O3(量分数y=0.0005%)。     

STUDY ON PHOTOCATALYTIC MECHANISM OF SOL-GEL-DERIVED Pb-DOPED TiO_2 THIN FILMS

Pb-doped TiO2 photocatalytic thin films were prepared on a soda-lime glass substrate via sol-gel method using TiO2 sol solution containing lead and characterized by X-ray photoelectron spectroscopy (XPS). The results showed that besides oxides of Ti(IV) there is a certain amount of oxides of To(Ⅲ) and Ti(Ⅱ) and Pb exists in the forms of PbTiO3 and PbO. The photocatalytic activity of the Pb-doped TiO2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange and photocatalytic mechanism mas also analyzed.     

Ba0.6Sr0.4TiO3料浆的稳定性研究

研究了pH值以及PMAA-NH4对Ba0.6Sr0.4TiO3水浆料稳定性的影响。由于Ba2 和Sr2 在较低的pH值条件下的溶出,使得粉体的等电点比较小,其等电点为pH=3.9。PMAA-NH4的加入使得粉体的Zeta电位向更负的方向移动,并且在0.4%时达到最大。在pH值为8—9,PMAA-NH4的加入量为0.4%时浆料的稳定性最好。