Effect of Antimony Addition on Electrical and Optical Properties of Tin Oxide Film

Antimony-doped tin oxide films were prepared on Corning glass substrate by chemical vapor deposition from a gas mixture of SnCl₄–SbCl₅–H₂O. The electrical conductivity and optical transmission of tin oxide films were studied with antimony doping. The film conductivity increased largely without losing optical transparency with a small addition of antimony. The increase of the conductivity was attributed mainly to more electrons donated by pentavalent Sb ions in the SnO₂ lattice. Large additions of antimony, however, diminished the conductivity, optical transparency, and crystallinity of the film. The diminution was found to be caused by fine Sb₂O₅ phases codeposited with SnO₂.     

排风余热回收型热泵热水器动态性能实验研究

提出了一种新型热泵热水器机组,利用浴室排风余热作为热源,通过热泵循环提高其能源品位后用于加热生活用水,并对其动态性能进行了实验研究.排风余热回收型热泵热水器全套装置全部置于室内,避免了空气源热泵机组在冬季工况下运行时室外换热器的结霜问题及热泵系统一年四季工况变化造成的压缩机压比过大、系统性能系数(COP)降低等问题,可在任何外界气候条件下高效稳定工作,且对浴室环境温度没有影响.实验结果表明,实验热泵热水器样机可在45 min内将85 kg水从18 ℃加热至出水温度50 ℃;当水箱出水温度在33～40 ℃时性能系数达到最大值为3.4,整个加热过程中的平均性能系数为3.15,平均耗功率为800 W.同时,实验发现冷凝盘管制冷剂上进下出布置方式可使水箱中水温产生严重的分层效应,从而产生较大的制冷剂过冷度,对于实验样机最大过冷度可达28 ℃.     

基于模型参考神经网络自适应异步电机无速度传感器矢量控制系统的研究

针对在传统的异步电机矢量控制系统中采用编码器、光电码盘等速度传感器来对转速进行检测给系统带来的一些缺陷,该文将模型参考方法和神经网络相结合,提出了一种模型参考BP神经网络的无速度传感器异步电机矢量控制方案,并设计了速度辨识环节.同时对系统进行了仿真和实验,结果表明:该方法具有较强的抗干扰能力,受电机参数影响小,能较好地估计电机转子的转速.     

Determination of the optimal production run in cases with multiple quality characteristics

This paper deals with the implementation of a multivariate loss function into the research area of optimal control of a deteriorating process with multiple quality characteristics of interest, in which the optimal production run length can be determined. During the production process, the means of the quality characteristics are assumed to drift away from the intended target values, and the drift behaviour of the quality characteristics are characterised by the deterministic trend and integrated moving average IMA(1,1). Numerical examples are provided to illustrate the application and usefulness of the proposed model. Sensitivity analyses are provided to study the impact of the process adjustment cost on the model. It is found that the optimal production run length can be significantly affected by changing this input parameter. Furthermore, some new directions for future research are outlined.     

True stress–strain analysis on weldment of heterogeneous tailor-welded blanks—a novel approach for forming simulation

This paper presents a novel experimental method of analysis to determine the tensile properties of weldment of the heterogeneous tailor-welded blank (TWB) and its base metal. A real-time microscopic recording system was developed to acquire the true stress–strain data of the weldment during tensile testing. Specially designed tensile specimens of the weldment were cut from the prepared stainless steel (AISI 304) TWBs with a thickness combination of 1 mm/1.2 mm. With the aid of a newly developed measurement system, the real-time deformation of laser-marked circular grids on the surface of the tensile specimens was captured. The deformation recorded made possible the determination of the stress and strain values of the weldment based on the assumption of plastic incompressibility. The accurately measured tensile data of the weldment is used to determine the localized necking based on the vertex theory. The localized necking criterion is implemented into a computer program, LS-DYNA, which is critical in the numerical simulation of the TWB forming. The simulation makes it possible accurate determination of the strain distributions in TWBs along the centerline perpendicular to the weldment. The predicted strain distributions were compared with those measured and found to be satisfactory, thus demonstrating the validity of the proposed experimental method to accurately determine the true stress–strain values of the weldment and the parent metals.     

空间微型合作目标捕获装置的研究

针对空间微型合作目标跟踪捕获任务,研制了具有稳定抓握、多感知、高刚度、高精度、大夹持力、大容错误差校正能力的新型捕获装置.其中,三指形手爪是带有手眼视觉的多传感型手爪,驱动链里加入一套高效率质量轻的反转自锁机构,同时手爪与微型目标器配合设计,冗余容错技术的引入及紧急解锁机构的设计保证了手爪的高可靠性.手爪的试验与测试,证明了手爪优越的抓捕性能与可靠性.     

Adaptive robust control design and experimental demonstration for flexible joint manipulators

A control design for flexible joint manipulator in the presence of nonlinearity and mismatched uncertainty is introduced. The control does not need the possible bound of uncertainty a priori. Only the existence of the bound is assumed. A state transformation is introduced via implanted control to tackle a mismatched system. The scheme utilizes the bounding function by combining states and parameters, which is to be estimated. Then an appropriate parameters update laws are designed to guarantee an asymptotic convergency by adopting Lyapunov approach. The control version shows that states converge to zero for the transformed system, and guarantees the uniform stability and boundness. This is also true for the original system in case either the gravitational force is absent or the system is coordinated such that the gravitational force converges to zero as link angles approach zero. The control performance is verified through experiments and shows an enhanced tracking performance for given references.     

Lead-free multilayer piezoelectric transformer

In this article, a multilayer piezoelectric transformer based on lead-free Mn-doped 0.94(Bi(12)Na(12))TiO(3)-0.06BaTiO(3) ceramics is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, is 8.3 mm long, 8.3 mm wide, and 2.3 mm thick. It operates in the second thickness extensional vibration mode. For a temperature rise of 20 degrees C, the transformer has an output power of >0.3 W. With a matching load resistance of 10 Omega, its maximum efficiency approaches 81.5%, and the maximum voltage gain is 0.14. It has potential to be used in low voltage power supply units such as low power adapter and other electronic circuits.     

Effects of defects on the thermal fatigue behavior of detonation-gun sprayed thermal barrier coatings

The effects of coating defects, such as pores and cracks, on the thermal fatigue behavior of zirconia based thermal barrier coatings (TBCs) have been investigated. Duplex TBCs, which are composed of an 8 wt.% Y₂O₃ stabilized ZrO₂ (YSZ) layer on top of a NiCrAlY bond layer were produced by detonation gun spraying. Thermal fatigue tests were conducted on three different TBC specimens, the YSZ layers of which were varied in terms of porosity and crack morphology, and failure analyses were subsequently carried out on the tested specimens. From these results, the roles of the defects on the thermal and mechanical degradation behavior of the TBCs were investigated.     

Ketamine effects on the urogenital system--changes in the urinary bladder and sperm motility

Different doses of ketamine (10 mg/kg, 20 mg/kg, 30 mg/kg, 40 mg/kg, 50 mg/kg, and 60 mg/kg) were injected i.p. (I.P.), respectively, to male ICR mice to determine the optimal dosage for chronic administration. At and above 40 mg/kg I.P. injection, mice had almost no hindlimb movement during swimming test. Subsequently, 30 mg/kg was used as the dose for the study in the toxicity of long-term ketamine administration on urinary bladder and sperm motility. The treatment group were subdivided into two (n = 10 each group); one received daily ketamine treatment i.p. for 3 months and another group for 6 months. Corresponding number of mice in control groups (n = 5 each group) received saline injection instead of ketamine. Terminal dUTP nick and labeling (TUNEL) study and Sirius red staining were carried out on the sectioned slides of the urinary bladders to study the degree of apoptosis in both epithelium and muscular layers of the urinary bladder and the relative thickness of the muscular layers in this organ was also computed. Apoptosis in the bladder epithelium was observed initially in the 3-month ketamine treated mice and the number of apoptotic cells was significantly different (P < 0.05) between the 3-month and 6-month ketamine treated mice and the control. The relative thickness of muscular layers in the bladder wall also decreased significantly (P < 0.05) when the 6-month treated mice and the control were compared. Sirius red staining revealed increase of collagen in the urinary bladder of the treated mice, most evidently 6 months after ketamine treatment. In addition, the sperm motility was studied and there was a statistically significant difference between the control and ketamine treated groups in the percentages of sperms which were motile (P < 0.05). This suggested that the chronic administration of ketamine affected the genital system as well.