Sintering and optical properties of transparent ZnS ceramics by pre-heating treatment temperature

The main objective of our work is to increase transmittance in the mid infrared region by removing impurities through the pre-heating treatment of zinc sulfide (ZnS) produced by hydrothermal synthesis. The pre-heating treatment proceeded at 450 to 600 °C for 2 h under vacuum atmosphere (10^?2 Torr). It was confirmed that the particle size increased as the pre-heating temperature increased. Additionally, all ZnS nano powders had a sphalerite (cubic) structure unaffected by pre-heating treatment. The ZnS nano powders were sintered by hot-press sintering method. As the pre-heating temperature increased, transmittance was improved due to the decreasing of porosity, increase of particle size, and the removal of impurities (carbon and sulfate). However, when the pre-heating treatment temperature was 600 °C, the transmittance slightly decreased due to the formation of a hexagonal phase. The ZnS ceramic with pre-heating treatment at 550 °C showed the highest transmittance (71.6%) and density (99.9%).     

A framework for modern manufacturing economics

Modern manufacturing economics is an interdisciplinary research subject which deals with the cycles of performance measurement, cost estimation, and decision analysis that are enmeshed with quantification of ill-structured benefits of advanced manufacturing technologies (AMT). This paper proposes a framework of modern manufacturing economics by examining recent research trends of AMT economics. It underscores integrated, quantitative, global, and strategic studies of AMT economics.     

Dry etching characteristics of HfAlO3 thin films in BCl3/Ar plasma using inductively coupled plasma system

In this study, we monitored the HfAlO₃ etch rate and selectivity to SiO₂ as a function of the etch parameters (gas mixing ratio, RF power, DC-bias voltage, and process pressure). A maximum etch rate of 52.6 nm/min was achieved in the 30% BCl₃/(BCl₃ + Ar) plasma. The etch selectivity of HfAlO₃ to SiO₂ reached 1.4. As the RF power and the DC-bias voltage increased, the etch rate of the HfAlO₃ thin film increased. As the process pressure decreased, the etch rate of the HfAlO₃ thin films increased. The chemical state of the etched surfaces was investigated by X-ray Photoelectron Spectroscopy (XPS). According to the results, the etching of HfAlO₃ thin films follows the ion-assisted chemical etching mechanism.     

核磁共振测井仪刻度系统机械结构设计

核磁共振测井仪刻度系统是把探头放在一个特殊的水套里进行测井,从而获得测量的输出数据与被测地层的固有物理参数的标准量值之间的转换关系。对核磁共振测井仪刻度系统的总体布局、刻度筒、刻度筒支架、岩心调节机构、循环系统等主要机械结构进行了优化设计,不仅可以完成仪器的刻度任务,而且可作为核磁共振测井技术的研究试验平台。     

Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds

Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials.     

ANSYS在腕力传感器结构设计中的应用

腕力传感器是一类重要的机器人传感器,腕力传感器的弹性体结构设计好坏直接影响到传感器的各项指标.由于腕力传感器结构复杂,各输出通道之间往往存在着干扰,通常采用实验的方法来进行标定,但标定的结果往往不够精确.利用所研制的一种新型机器人多维腕力传感器的结构,提出了一种利用有限元分析软件ANSYS对其维间干扰作定量分析的方法,分析结果证实了该传感器弹性体结构设计的合理性.     

液压挤压对复合铸造Al3003/Al4004包覆材料显微组织的影响(英文)

研究液压对混合复合铸造Al 3003/Al 4004包覆材料微观组织变化的影响。复合铸造Al 3003/Al 4004包覆材料试样为圆形,由Al 3003(外部)和Al 4004(内部)材料组成。采用液压设备,在温度423 K、挤压比5的条件下制造试样。在挤压之前,Al 4004材料的直径为80 mm,Al 3003材料的厚度为35 mm,在挤压后,2种材料的直径和厚度分别为30 mm和5 mm。研究了2个试样的微观组织和硬度。在挤压之前,复合铸造Al 3003/Al 4004包覆材料横截面的硬度以抛物线的形式向中心增大。然而,在挤压后,Al 4004材料的硬度几乎没有变化。在挤压之前,Al 3003和Al 4004材料的界面存在大量直径超过1 mm的大空洞,这些大空洞随着液压过程的进行而消失。     

FABRICATION AND ELECTRICAL PROPERTIES OF PZT-PVDF 0–3 TYPE COMPOSITE FILM

ABSTRACT

A film speaker was fabricated with 0–3 type piezoelectric composite. The 0–3 type composite was developed to incorporate the advantages of both ceramic and polymer. The pastes of PZT-PVDF composite were made with various mixing ratio. The paste was printed by conventional screen-printing method on ITO (Indium Tin Oxide) bottom electrode which was deposited on PET (polyethylene terephthalate) polymer film. The prepared composite film was about 80 μm in thickness. After printing the top-electrode of silver-paste, 4 kV/mm of DC field was applied at 120°C for an hour to align the electric dipole in the 0–3 composite film. The piezoelectric charge constant of d₃₃ was increased with increasing the PZT weight percent. The maximum value was 24 pC/N at 70 wt% of PZT. But the piezoelectric voltage constant of g₃₃ had the maximum value about 32 mV · m/N at 65 wt% of PZT. The SPL (Sound Pressure Level) of the speaker fabricated with the 65:35 composite film was tested at various driving voltages of 1 ～ 100V_rms. The SPL was saturated at the driving voltage of 70V_rms and the value was about 68 dB at 1 kHz.