河网非恒定流隐式方程组的汊点分组解法

本文在现有研究成果的基础上，提出了一种汊点分组解法其特点是能够根据实际问题的需要，灵活方便地将河网中的汊点划分为任意多组，使汊点方程组的系数矩阵压缩到与分组后每组中的汊点数相同的阶数不仅极大地压缩了系数矩阵的贮存量，而且计算量大幅度减少，计算精度也得到了保证     

Bistable C1 ferroelectric liquid crystal device for e-paper application

Recent progress in both low pretilt and high pretilt defect-free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices for e-paper application is reviewed. First, by using numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, we found it is possible to achieve a zigzag-free C1 state by low azimuthal anchoring alignment with a low pretilt angle. The critical azimuthal anchoring coefficient for defect-free C1 state is calculated. Its relationship with elastic constants, chevron angle, and surface topography effect are also discussed. Second, by using 5° oblique SiO deposition alignment, a defect-free, large memory angle, high contrast ratio, and bistable C1 SSFLC display, which has potential for electronic paper applications has also been developed. The electro-optical properties and bistability of this device have been investigated. Various aspects of defect control are also discussed.     

燃料油在隧道窑上的应用探讨

隧道窑由于燃用重油造成生产成本升高，为此探讨采用煤焦油沥青配制的燃料油替代重油燃烧。通过调节燃料油的温度和加入蒽油的比例解决了其粘度过大造成燃烧不完全的问题；同时改进烧嘴结构，使雾化效果更好，燃烧更加完全。试验证明，隧道窑燃用燃料油经济可行。     

Measurement of the Dielectric Parameters of a Ferroelectric Material by a Controlled Discharge Method

It is proposed to determine the dielectric parameters of a ferroelectric material from the form of the voltage after a short discharge of a charged sample.     

考虑随机风影响的隧道通风量计算

现有隧道内通风量计算偏保守,往往需开启更多风机,导致能源浪费严重。本文提出一种考虑随机自然风影响下的隧道内通风量计算方法。将风频引入隧道通风量计算中,指出隧道内风频的两种表示方法,离散型风频分布和韦布尔风频分布,通过最小误差逼近算法计算韦布尔风频分布中的尺度系数A和形状系数K。通过算例可得,进口处考虑随机风比不考虑随机风的通风量多37.8%,说明考虑随机风影响可明显降低风机开启数量。     

3D imaging application in the studies of micro air vehicles

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft's flexible aerodynamic surface. The aircraft models with deformable aerodynamic shape were designed and tested in a purpose-built wind tunnel experimental environment. After calculation of SIFT feature points and subdivision of triangular meshes, deformable surface of the aircraft's aerodynamic shape was represented. The aircraft's 3D visualization was used for analyzing unsteady deformation in the aerodynamic shape under external airflow disturbances. The results, together with aerodynamic forces measured in the experiment, will be useful to improve the flight performance and disturbance resistance ability of micro air vehicles.     

近化学计量比LiNbO3晶体电畴结构观察和机理探讨

采用双坩埚提拉法(DCCZ)生长了各种不同成分的近化学计量比LiNbO₃晶体, 并用腐蚀法观察了其电畴结构. 结果表明, 化学成分对未经极化处理晶体的电畴结构起决定性作用, 当Li₂O 含量处于49.4mol%附近时, 晶体z面电畴呈现特殊的三次对称反畴; 当晶体中Li₂O含量为49.7mol%时, 晶体为完全单畴. 本文对其形成机理进行了探讨, 认为在由顺电相向铁电相转变 时, 局部铁电畴的极性方向与该处沿z轴方向的温度梯度正负密切相关, z轴生长晶体时, 由于相变发生所处位置离生长界面的距离受LiNbO₃晶体计量比影响, 所处温场固有温梯也 随之不同, 在此基础上解释了不同成分晶体的电畴结构形成原因. 最后讨论了控制铁电畴结构的工艺措施.     

Stochastic aspects of bridge deck aeroelasticity under turbulent flow

Returning to an earlier frequency-domain analysis of the problem of long-span bridge response to ambient winds, the paper emphasizes the indispensable experimental information necessary to bring results into conformity with full-scale prototype action. Focus is placed upon the use of a sectional wind tunnel model under simulated turbulent flow as the prime source of this information, which consists principally of the flutter derivatives and the spectra of the wind forces, both obtained under turbulent flow. The effect of three-dimensional turbulence upon the flutter derivatives is observed to influence structural stability in a manner consistent with that observed in full-bridge wind tunnel models.     

多孔PZT95/5铁电陶瓷的机械性能和铁电性能研究

采用添加造孔剂的方法制备多孔锆钛酸铅(PZT95/5)铁电陶瓷, 研究了孔结构包括孔隙率、孔径及孔形状对多孔PZT95/5陶瓷机械性能和电性能的影响及机理, 并揭示多孔PZT95/5陶瓷微观结构、机械性能和铁电性能的内在联系。研究表明: 孔隙率的增加降低了多孔PZT95/5陶瓷的声阻抗, 改善了陶瓷与封装材料的声阻抗匹配. 孔隙率增加, 多孔PZT95/5陶瓷的屈服应力和剩余极化强度降低, 矫顽场强增大。孔结构对多孔PZT95/5陶瓷屈服应力的影响可由应力集中理论解释; 多孔PZT95/5陶瓷剩余极化强度随孔结构的变化可用内应力结合空间电荷理论加以解释。