Study of residual stresses in tailor rolled blanked Al5J32-T4 sheets

Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization.Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the disadvantages of a welding process which was used in joining panel components.TRB offers better structural design capabilities due to the seamless transitions on the panels with different thicknesses.In spite of the advantages of the process, TRB leaves internal stresses in the panel.This residual stresses lower the formability of Tailor Rolled Blanked (TRBed) parts and cause cracks near severe curvature during subsequent forming processes.In this research, the residual stresses of TRBed Al5J32-T4 sheets were studied by X-ray stress analysis, and also microstructure was observed along the rolling direction.In addition, heat treatment was done after TRB process in order to compare the residual stresses to that of the TRBed sheets before the heat treatment.     

Al-C-Ni组分的变化对Al-C-Ni与ITO层接触电阻的影响

为克服大尺寸显示面板中反应时间的延迟问题,采用低阻栅线是十分有益的,同样在小尺寸面板上也存在这种相互匹配的过程。然而,由于Al较高的氧化速度,铝合金和ITO材料接触性能并不太好。文章介绍了在室温ITO沉积过程中,通过增加ACX(Al-C-Ni)中Ni含量来减少ACX-ITO接触电阻。经室温ITO沉积后,接触电阻成功地减少到300Ω,而且没有ACX引起的问题出现。     

A new type of ordering in Ba(Zn1/3 Ta2/3)O3 ceramics

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

微波辐射辅助柠檬酸络合法制备的Ho3+/Tm3+/Yb3+共掺杂CaWO4的白光性能（英文）

采用微波辐射辅助柠檬酸络合法制备Ho3+/Tm3+/Yb3+共掺杂CaWO4纳米晶升频转换荧光粉。将柠檬酸络合物前驱体在300~700°C热处理3 h。Ho3+/Tm3+/Yb3+共掺杂CaWO4C在400°C时开始结晶,在600°C时结晶完成。经600°C热处理的Ho3+/Tm3+/Yb3+共掺杂CaWO4主要呈球形,且形态均匀。在980 nm的激光激发下,Ho3+/Tm3+/Yb3+共掺杂CaWO4纳米晶出现肉眼可见的明亮的白色升频转换发射,这种现象来自Tm3+的475 nm蓝光发射以及Ho3+的543 nm绿光和651 nm红光发射。通过调整Tm3+和Ho3+的浓度可以控制Ho3+/Tm3+/Yb3+共掺杂CaWO4的CIE色度图从冷到暖白色之间变化。讨论了Tm3+和Ho3+浓度对升频转换光性能的影响以及与激光泵功率相关的影响机制。     

固体氧化物燃料电池离子- 电子混合传导性Ni/ScSZ 燃料极的制备以及性能分析

在薄膜固体氧化物燃料电池中,为增加发生电化学反应的三相界面面积,燃料极和空气极通常制备成离子-电子混合传导性质的多孔形态。该研究将燃料极电化学反应(氢氧化反应)的催化剂——镍(Ni)和氧离子传导性好的氧化钪稳定的氧化锆(ScSZ)混合制备成离子-电子混合传导燃料极。实验结果显示,与纯 Ni 燃料极相比,所制备的 Ni/ScSZ 燃料极因其三相界面面积的增加,可显著降低极化电阻,但同时欧姆电阻也显著增加,从而最终导致燃料电池单池性能总体下降。     

Limit load analyses of helical coiled steam generator tubes with a volumetric flaw

Maintaining structural integrity of piping has always been an important effort in the nuclear power industry. To resolve piping issues such as unanticipated failures caused by diverse planar and volumetric flaws, several guidelines were developed and used especially for assessment of steam generator tubes. However, because the major components of new reactors have dissimilar geometric features and loading conditions compared with those of conventional operating reactors, most of existing assessment methods are not expected to be applicable; therefore, new alternative assessment guidelines are required. In this paper, a systematic structural integrity assessment of helical coiled steam generator tubes for a small and medium modular reactor, which is currently being designed, is introduced. Three‐dimensional detailed finite element (FE) limit analyses have been carried out to simulate the behaviours of the tube containing a volumetric flaw such as elliptical wear‐type, rectangular wear‐type and tapered wear‐type defects subjected to external pressure. Failure pressures were calculated from the FE analyses by changing defect depth, defect length and defect angle affecting the load‐carrying capacity of the tube. Thereby, engineering equations were developed as a function of these key parameters to predict structural failures and system reliability to enable more reasonable design and manufacturing decisions.     

Texture Weakening Effects in Ce-Containing Mg Alloys

The purpose of the present study is to elucidate the cause of a texture transition observed in hot-rolled Mg-Ce alloys, with increasing Ce content. More dilute compositions show a predominance of basal 〈a〉 dislocations, while the more concentrated alloys are shown to contain significant populations of 〈c+a〉 and non-basal 〈a〉 dislocations in the as-rolled and the recovery-annealed conditions. Like Mg-Nd, the grain size in Mg-Ce decreases with increasing Ce. Unlike Mg-Nd, the second-phase particles observed are of the equilibrium phase, and the equilibrium solid solubility at the hot working temperature corresponds to the composition above which weak textures form. The significances of both non-basal slip and Zener pinning as contributors to texture randomization are discussed.     

低功耗TFT-LCD驱动方法

为了降低薄膜晶体管液晶显示器(TFT-LCD)的功耗,提出了一种新的双栅之型反转驱动方法。研究了双栅之型反转驱动技术的节能原理,完成了相关结构设计、电路设计,制作了35.6cm(14in)WXGA(1 366RGB×768)样品,测试并分析了节能效果。结果表明,该技术可以有效降低TFT-LCD的功耗,在显示彩条画面的情况下,液晶屏模拟电源功耗降低了70%(191mW)。分析了出现的莫尔条纹问题,并提出了解决方案。该研究为降低TFT-LCD及其他显示设备的功耗提供了一种驱动方法及设计参考。     

Test Results for Leakage and Rotordynamic Coefficients of Floating Ring Seals in a High-Pressure,High-Speed Turbopump

Test results are presented for short floating ring seals (D = 53.0 mm, L/D = 0.15) using a smooth surface and a round-hole pattern defined as a damper floating ring seal (h/C_r = 3, γ = 0.34: the ratio of hole area to surface area) for supplied pressures of 3.0, 5.0, and 7.0 MPa, respectively, with the shaft operating speed up to 24,800 rpm. The measured data includes leakage, attitude angle, eccentricity ratio, and rotordynamic coefficients such as stiffness, damping, and inertia. When the floating ring seals are locked up, the eccentricity ratio of the smooth surface floating ring seal is lower than that of the damper floating ring seal. The attitude angle increases linearly with the operating speeds. The damping coefficients of the damper floating ring seal are higher than those of the floating ring seal. Whirl frequency ratios of the floating ring seal are lower than the damper floating ring seal with high eccentricity ratio at low operating speed range. The design parameters determined from these test results will be used for high-pressure and high-speed turbopump seals in a liquid rocket engine system.     

C型炭纤维阳极氧化处理及其增强ABS复合材料的研究

以NH4NO3为电解质,对C型通用级沥青基炭纤维在不同条件下进行阳极氧化表面处理,并通过SEM、力学性能测试等方法考察了纤维及其复合材料的性能,发现经氧化处理后,炭纤维表面粗糙度和含氧官能团如C-O、C=O、COOH等数目明显增大,CF/ABS复合材料的界面粘结性得到有效地改善;复合材料的拉伸强度、弯曲强度及模量有所提高,断裂形式由纤维拔出转变为纤维断裂。