激光陀螺用压电陶瓷材料的制备与研究

通过文献调研设计了压电陶瓷配方,使用传统固相法制备目标压电陶瓷以达到大应变要求,以应用于激光陀螺激光稳频器中,通过r(Zr)/r(Ti)系列实验可得r(Zr)/r(Ti)=46/54组成在1 180℃烧结时获得最佳的压电介电性能,即压电常数d33≈640pC/N,弹性刚度系数cE11=60.61GPa,相对介电常数εT33/ε0≈3 300,介电损耗tanδ≈1.85%,机电耦合系数kp=0.655,居里温度TC=272℃。X线衍射(XRD)分析确认相界组成为r(Zr)/r(Ti)=46/54,扫描电镜(SEM)表明烧结温度对陶瓷晶粒尺寸有显著影响,在1 180~1 200℃之间晶粒尺寸显著增大。     

半导体量子点在白光LED中涂覆厚度的确定

在蓝光LED上涂覆黄光量子点是合成白光LED的重要方法之一,确定量子点的涂覆厚度是合成白光的一个关键步骤。引入厚度系数来模拟厚度,证明了一定厚度范围内,厚度系数与厚度的线性关系。根据光谱的线性叠加以及能量守恒定律,建立数学模型,编程计算,结合实验,确定量子点厚度。按照模拟计算得到的厚度涂覆LED芯片,即可获得白光LED。本方法可以为实际生产提供指导,提高生产效率。     

两种主要高强度套管的耐磨性能试验

套管磨损是深井、超深气井钻井过程中困扰作业人员的突出问题,摸清P110和V140这两种主要钢级的高强度套管的耐磨性能对于钻井设计选用套管具有重要意义。为此,采用美国摩尔技术公司的全尺寸套管磨损试验机,模拟油气田现场的钻井作业参数以及钻井液配方,开展了钻杆接头与套管内壁间低、中、高3种典型的侧向力对P110和V140钢级套管的全尺寸实物磨损试验研究,检测并对比分析了磨损套管试样在不同磨损时间段的磨损沟槽深度、沟槽宽度、磨损系数、摩擦系数以及磨损体积等参数,并对套管摩擦表面进行了扫描电镜分析,进而探讨了不同工况条件下的套管摩擦机理。结果认为:在低侧向力的情况下,两种套管的磨损情况基本相当;在中等侧向力的情况下,V140套管的磨损比P110套管严重;在高侧向力的情况下,P110套管的磨损明显要大于V140套管;随着钻杆接头与套管内壁之间接触侧向力的增加,摩擦副之间的摩擦系数增大且处于黏着磨损状态。该研究成果对于在套管柱设计中根据不同井眼曲率考虑套管的耐磨性能选用套管具有参考价值。     

平坦地面条件下装备间天线电磁耦合度分析

分析了地表面反射系数以及地面土壤介质的介电特性,研究了车体结构对天线辐射特性的影响,仿真得到了车体模型、地面介质、距离等因素对天线间耦合度的影响,建立了平坦地面条件下,通信车的收发天线间电磁耦合度的精确的仿真模型.经与实测数据对比分析,仿真结果与实测数据变化规律一致,最大误差16.54 dB,均方差4.21 dB.     

基于反射式太赫兹时域谱的水太赫兹光学参数测量与误差分析

利用垂直反射式太赫兹时域光谱(THz-TDS)技术 测量了水的THz光学参数并对测 量误差进行了分析。测量过程中,把高阻Si片的空气-Si表面作为参考信号,Si-水表面最 为样 品信号,通过两者之比的传输函数计算得到了水的THz折射率和吸收率,然后应用误差传 播理论分析这些光学参数的误差。结果发现,折射率和吸收率误差中,由多次测量引入的随 机 误差在0.1~1.1THz范围内基本不变,而在接近0.1THz和1.1THz处误差变大,即呈现U型 分布。这表明,在接近0.1THz和1.1THz时, THz-TDS仪器的测量灵敏度下降;由高阻Si片厚 度和Si折射率误差引入的误差比THz-TDS多次测量引入的随机误差大得多,在 0.1~1.1THz 范围对应的水折射率误差分布较均匀,而对应水的吸收率误差随着频率的增加而增大。本文 的方法同样适用于类似的垂直反射式THz-TDS系统提取其它材料的THz光学参数及其误差 分析。     

Wind Force Coefficients for Designing Porous Canopy Roofs

Wind force coefficients for designing porous canopy roofs have been investigated based on a series of wind tunnel experiments. Gable, troughed and mono-sloped roofs were tested. The roof models were made of 0.5 mm thick perforated duralumin plates, the porosity of which was changed from 0 to about 0.4. Overall aerodynamic forces and moments acting on the roof model were measured in a turbulent boundary layer with a six-component force balance for various wind directions. The results indicate that the wind loads on canopy roofs generally decrease with an increase in porosity of the roof. Assuming that the roof is rigid and supported by the four corner columns with no walls, the axial forces induced in the columns are regarded as the most important load effect for discussing the design wind loads. Two loading patterns causing the maximum tension and compression in the columns are considered. Based on a combination of the lift and moment coefficients, the design wind force coefficients on the windward and leeward halves of the roof are presented for the two loading patterns as a function of the roof pitch and porosity. The effect of porosity is taken into account as a reduction factor of the wind loads.     

暖边间隔条对幕墙热工性能的影响

随着节能环保日益成为社会的共识,拥有更好隔热效果的新型玻璃在玻璃幕墙中被不断应用,暖边隔热条作为新型玻璃的主要技术手段使用也越来越广泛。本文主要对玻璃的暖边隔热条在不同幕墙体系中的实际使用效果进行了分析并得出相应结论,避免人们在建筑中盲目追求暖边隔热条造成不必要的浪费。     

反渗透膜元件透过系数的试验与数学求解

明确了反渗透膜元件两透过系数求解所需的函数形式、幂项数、试验组数、试验点位、变量归一、回归分析及回归效果检验等一系列试验与数学过程,并给出了某支膜元件两透过系数求解的试验数据及其计算实例。     

Efficient calculation of daylight coefficients for rooms with dissimilar complex fenestration systems

The daylight coefficient (DC) method is a powerful and efficient method to perform annual daylight illuminance simulation. A set of coefficients are calculated for a given room space and static fenestration systems prior to simulation start. Time series of indoor daylight illuminances are obtained by only knowing the sky luminance. However, for rooms with dissimilar dynamic complex fenestration systems (such as windows with movable shadings) whose optical behaviour (transmission, reflection and scattering) may change during simulation, the efficiency of the DC method may be compromised as another whole set of coefficients must be re-calculated. This study presents the development of a new methodology to compute the DC set for rooms with dissimilar complex fenestration components only once prior to simulation start. A validation study is carried out, in which the daylight illuminances in an office space equipped with a clear window and internal Venetian blinds are compared using predictions from the present model, the Radiance program, as a benchmark model employing detailed optical model of Venetian blinds, and the Daysim program employing a simple engineering blinds model. Findings from the validation study show that the present model yields overall accurate results when compared with the benchmark model for any window orientation, although some local illuminance differences are observed in areas under direct sunlight exposure.