Reactive Atmospheric Plasma Spraying of AlN Coatings: Influence of Aluminum Feedstock Particle Size

Feedstock powder characteristics (size distribution, morphology, shape, specific mass, and injection rate) are considered to be one of the key factors in controlling plasma-sprayed coatings microstructure and properties. The influence of feedstock powder characteristics to control the reaction and coatings microstructure in reactive plasma spraying process (RPS) is still unclear. This study, investigated the influence of feedstock particle size in RPS of aluminum nitride (AlN) coatings, through plasma nitriding of aluminum (Al) feedstock powders. It was possible to fabricate AlN-based coatings through plasma nitriding of all kinds of Al powders in atmospheric plasma spray (APS) process. The nitriding ratio was improved with decreasing the particle size of feedstock powder, due to improving the nitriding reaction during flight. However, decreasing the particle size of feedstock powder suppressed the coatings thickness. Due to the loss of the powder during the injection, the excessive vaporization of fine Al particles and the completing nitriding reaction of some fine Al particles during flight. The feedstock particle size directly affects on the nitriding, melting, flowability, and the vaporization behaviors of Al powders during spraying. It concluded that using smaller particle size powders is useful for improving the nitriding ratio and not suitable for fabrication thick AlN coatings in reactive plasma spray process. To fabricate thick AlN coatings through RPS, enhancing the nitriding reaction of Al powders with large particle size during spraying is required.     

Static joint strength of friction welded joint between aluminium alloys and stainless steel

Arc welding robots have rapidly come into widespread use. However, because of the special characteristics of aluminium such as softness, good conductivity and a liability to form an oxide film on the material surfaces, welding itself is inherently difficult and its robotisation has lagged behind other materials. Our company has considered robots and welding equipment together as welding systems and produced aluminium welding robots which are easy to handle and of high reliability.

In addition, in our company off‐line teaching is considered to be a more flexible approach to a multiplicity of small quantity production tasks compared with the play back principle which is generally used in present welding robots.     

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS XXXIX. SYNTHESIS OF TITANIUM(IV) ANTIMONATES AND THEIR ION EXCHANGE PROPERTIES FOR ALKALI AND ALKALINE EARTH METAL IONS

ABSTRACT

Titanium antimonate (TiSbA) cation exchanger, prepared under different molar ratios of titanium and antimony, has been characterized by X-ray diffraction, thermal analysis, infrared spectra, and pH-titration. The pH-titration curves showed apparently monobasic acid type. The uptakes of alkali metal ions increased with increasing pH of the solution and with decreasing the molar ratio (Ti/Sb) in the exchanger. An unusual selectivity sequence of the order Na < K < Rb < Cs was found for microamounts of alkali metal ions on TiSbA, while the regular selectivity sequence Mg < Sr < Ba was found for alkaline earth metal ions in nitric acid media. The maximum separation factors, ∝^Li _Na(=55) and ∝(=186) were found on the TiSbA with Ti/Sb molar ratio of 1.56, respectively. The effective separations of Li from Na and K, Mg from Ca and Sr have been achieved by using a relatively small column (2 cm × 0.5 cm i.d. ) containing TiSbA of Ti/Sb ratio 1.56.     

Flow visualization and numerical analysis of a new mixing equipment with vibratory fins

The mixing performance of a new type of mixing equipment which has several fin oscillators on a pair of shafts with a vibrating motor was investigated. This mixing equipment, which is mainly used for industrial plating processes, was usually operated at a vibrating frequency of about 40 Hz with the amplitude 1 mm. The flow visualization in this equipment showed that the flow in the vessel at laminar flow region was vertically divided into two distinct symmetric regions. The numerical simulation of the flow and the mixing patterns agreed well with the visualization result at laminar flow region.     

Anti-Ro/SSA-associated annular erythema in childhood

We report four children with anti-Ro/SSA positive who presented with an annular erythema as a manifestation of Sj?gren's syndrome. One patient had an aseptic meningoencephalitis as well as cutaneous lesions. Children with annular erythema should be carefully followed for features of Sj?gren's syndrome, which is believed to be a rare condition in children.     

Manufacturing pressurized creep tubes from highly purified V-4Cr-4Ti alloys, NIFS-Heat2

A fabrication process for pressurized creep tubes (PCTs) for a highly purified V-4Cr-4Ti alloy, NIFS-heat2 was established. No increase in impurity contents in PCTs was detected during the tube manufacturing process. In a preliminary thermal creep test, homogeneous deformation was observed over entire tube length, which verifies reliability of creep measurement by using the present PCTs.     

High-Speed Facsimile Recording with Laser Light Sources

This paper describes improvements in facsimile receivers for newspaper transmission made by replacing conventional crater tube light sources with He-Ne laser lights. This replacement allows the system to operate at wider frequency bandwidth and provides stronger writing light intensity and longer system durability. The light intensity of the writing source is modulated by a Teglass acoustooptic modulator developed at the present laboratory and is operated under Raman-Nath mode of diffraction. Instabilities in the system have been corrected by a feedback loop using one of the two first-order diffracted lights as an intensity watcher. Experiments show that a filmed image with a transmission density of 3.9 and density rising time of 1μs can be obtained by using an acoustooptic modulator operated at a driving frequency of 40 MHz, an RF power of 300 mW, and an incident light beam diameter of 1 mm.     

Immunohistochemical characterization of transplantable rat squamous cell carcinoma (FF-6) in skin and thymus

FF-6 is a transplantable squamous cell carcinoma which originally arose in the facial skin of a DA rat. It was established after maintaining the tumor in the subcutaneous tissue or peritoneal cavity of DA rats conventionally for over 30 generations. When the soybean-sized original FF-6 tumor was transplanted subcutaneously, it became an oval, hard, whitish, solitary and thumb-head-sized nodule within one month. After intraperitoneal transplantation of FF-6, it formed many nodules ranging from miliary to thumb-head size, which adhered and/or metastasized to many abdominal organs. When FF-6, cut into small pieces, was injected into the lower lip, the tumor grew bigger in situ, and metastasized to regional lymph nodes. Histologically, FF-6 was characterized as a well-differentiated squamous cell carcinoma, showing positive staining with anti-keratin, anti-laminin, anti-collagen type IV, anti-fibronectin and UB-14 antibodies. This transplantable tumor may be useful for analyzing the mechanisms of proliferation and metastasis of squamous cell carcinoma in vivo, and the host defence mechanism in rats, as well as being a suitable model of human squamous cell carcinoma.     

High-performance 0.10-μm CMOS devices operating at roomtemperature

The authors have fabricated 0.10-μm gate-length CMOS devices that operate with high speed at room temperature. Electron-beam lithography was used to define 0.10-μm polysilicon gate patterns. Surface-channel type p- and n-channel MOSFETs were fabricated using an LDD structure combined with a self-aligned TiSi₂ process. Channel doping was optimized so as to suppress punchthrough as well as to realize high transconductance and low drain junction capacitance. The fabricated 0.10-μm CMOS devices have exhibited high transconductance as well as a well-suppressed band-to-band tunneling current, although the short-channel effect occurred somewhat. The operation of a 0.10-μm gate-length CMOS ring oscillator has been demonstrated. The operation speed was 27.7 ps/gate for 2.5 V at room temperature, which is the fastest CMOS switching ever reported