Piezoelectric and dielectric properties of PZN-BT-PZT solid solutions

Pb(Zn_1/3Nb_2/3)O₃ ceramics with the perovskite structure can be stabilized by substituting 6–7 mol % BaTiO₃ (BT). Piezoelectric and dielectric properties of the pseudo-binary system (1–x)(0.94PZN-0.06BT) -xPb(Zr_(1–y)Ti_y)O₃ were studied, and the effects of Zr/Ti ratios and thermal annealing process on the piezoelectric and dielectric properties were also discussed. The results show that the piezoelectric properties of this ceramic system are very good when x is about 0.50 and y is about 0.47 with K_p = 70%, d₃₃=560 pC/N, _m #x2248;23,000. These ceramics are favorable to piezoelectric actuators.     

PS-b-PNIPAAm嵌段共聚物多孔薄膜的制备及形貌研究

将两亲性PS-b-PNIPAAm嵌段共聚物(BCP)溶解在四氢呋喃中配制成浓度为2%(质量分数)的溶液,旋涂后得到初生嵌段共聚物薄膜,以乙醇为退火溶剂退火后,探讨了退火时间对薄膜微孔结构的影响,结果表明,随着退火时间的延长,膜表面的微相分离越明显,微孔结构的分布更均匀。进一步将在乙醇中退火预处理的薄膜分别在乙醇或去离子水中进行溶胀处理,通过选择性溶胀成孔法制备PS-bPNIPAAm纳米多孔膜。研究了溶胀时间、温度及溶剂类型对薄膜形貌的影响,结果发现升高溶胀温度和延长溶胀时间均有助于膜表面微孔结构的形成,且该过程中乙醇的成孔作用比水的作用更为明显。     

染料敏化太阳能电池对电极的研究进展

简要说明了染料敏化太阳能电池中对电极的作用,指出对电极是染料敏化太阳能电池的重要研究方向。详细介绍了各类对电极的特点和制备工艺,通过对比发现,铂对电极性能最好,但高成本限制了它的应用;价格低廉、性能较高的碳和聚合物对电极的发展前景广阔。最后论述了对电极的发展方向和国内外的研究现状。     

DH型离心空压机旋转失速故障诊断及治理

旋转失速是压缩机的常见故障 ,但诊断该故障时易和其他故障相混淆。本文从旋转失速的振动机理出发 ,归纳了旋转失速的故障识别特征。旋转失速的特征频率是成对出现的 ,随流量的减少而降低。该故障特征在现场诊断时得到验证 ,并成功应用于现场诊断     

一种新型的激光—等离子体辅助化学气相沉积装置的研究

为探索用激光离子体共同辅助化学气相沉积过程以实现室温沉积的可能性，设计并制造了一种新型的ＣＶＤ装置，实际了ＳｉＨ４－ＮＨ３－Ｎ２体系制取Ｓｉ３Ｎ４膜的试验。结果表明，激光和等离子体是可以相互促进，共同辅助ＣＶＤ过程的，且两者均处于较代的能量水平。     

中厚板矫直过程中中性层偏移动态研究

研究中性层偏移对矫直力的影响,以提高矫直力精度。通过对矫直件三维弹塑性变形进行分析,提出中性层偏移理论,利用数值模拟和实验讨论中性层偏移的动态变化规律,说明中性层偏移是影响矫直力精度的重要因素之一,并验证了理论推导公式与数值计算结果之间的误差,为建立更为准确的矫直力模型提供理论基础和数据。     

Binuclear aluminum complex as an efficient orange emitter in single-layer electroluminescent devices

A binuclear aluminum complex with a chelating anilido-imine conjugated Schiff base ligand, 1,4-{o-C₆H₄[N(2,6-ⁱPr₂C₆H₃)][CH  N]Al(CH₃)₂}₂C₆H₄ (3), was synthesized from the alkane elimination reaction of trimethylaluminum with the free ligand, 1,4-{o-C₆H₄[NH(2,6-ⁱPr₂C₆H₃)][CH  N]}₂C₆H₄ (2), at room temperature. The photophysical properties of complex 3 were briefly examined and it was found that complex 3 displays bright orange luminescence in solution and in solid state. Electroluminescent devices were fabricated by doping complex 3 in polymer blend host of poly(vinylcarbazole) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazol using simple solution spin-coating technique. Efficient orange light emission was obtained from the fabricated single-layer organic light-emitting devices with a maximum current efficiency of 3.2 cd/A.     

Maximum-likelihood mixture factor analysis model and its application for process monitoring

In the present paper, a mixture form of the factor analysis model is developed under the maximum-likelihood framework. In this new model structure, different noise levels of process variables have been considered. Afterward, the developed mixture factor analysis model is utilized for process monitoring. To enhance the monitoring performance, a soft combination strategy is then proposed to integrate different local monitoring results into a single monitoring chart, which is based on the Bayesian inference method. To test the modeling and monitoring performance of the proposed mixture factor analysis method, a numerical example and the Tennessee Eastman (TE) benchmark case studies are provided.     

动载滑动轴承瞬态油膜的全景实验研究

在搭建的滑动轴承实验台上,对大扰动工况下油膜全景空穴分布图像及油膜压力进行瞬态同步采集,并对图像进行后处理,以便于观察并与基于质量守恒边界条件的理论仿真结果对比,并对同一旋转周期内油膜空穴分布和不同工况下油膜压力进行对比分析。结果表明：油膜全景图像经过后处理转化为油膜原形展开图像后,图像直观,且更易于对比分析;在大扰动工况下,油膜空穴区域随最大动偏心位置迁移而迁移。