The particle reinforced composite fabricated by a powder-in sheath rolling (PSR) method was severely. deformed by the accumulative roll-bonding (ARB) process. The ARB process was performed up to 8 cycles at ambient temperature without lubricant. The ARBed composite exhibited an ulbricant. grained structure similar to the other ARBed bulky materials. Tensile strength of the composite increased gradually with the number of ARB cycles, but from the 6th cycle it rather decreased slightly. These characteristics of the composite were somewhat different from those of Al powder compact fabricated by the same procedures. The difference in microstructure and mechanical properties between Al powder compact and the composite was discussed

The alumina dispersion-strengthened (DS) C15715 Cu alloy fabricated by a powder metallurgy route was annealed at temperatures ranging from in the air and in vacuum. The effect of the annealing on microstructural stability and room-temperature mechanical properties of the alloy was investigated. The microstructure of the cold rolled OS alloy remained stable until the annealing at in the air and in vacuum. No recrystallization of original grains occurred, but the dislocation density decreased and newly formed subgrains were observed. The alloy annealed at in the air experienced recrystallization and grain growth took place, however annealing in vacuum at did not cause the microstructural change. The mechanical property of the alloy was changed slightly with the annealing if the microstructure remained stable. However, the strength of the specimen that was recrystallized decreased drastically.

We plan to install the polarimetric optics in the AGU(acqusition and guiding unit) of the 1.8 m telescope at the BOAO(Bohyunsan Optical Astronomy Observatory). With this, the spectropolarimetric observations with the resolution of 45,000 and 60,000 in 4,000 to 8,000＼AA ange could be done by the BOES(BOao Echelle Spectrograph). If we use the precision radial velocity measurement capability of the BOES, the accuracy of the magnetic field intensity measurements with this new BOES stokesmeter will be much increased. We present here the design concept of the BOES stokesmeter. Some details on the optics, mechanical parts, fiber parts and the lab test procedures of this stokesmeter are explained.

We present a high resolution spectrum of PU Vul observed at Bohyunsan Optical Astronomy Observatory (BOAO) on April 9, 2004. Permitted emission and nebular lines of PU Vul had been significantly changed compared to all spectra observed since its eruption in 1979. Therefore all new lines should be re-identified and were done so. We do-convoluted a Hβ line into several emission components with Gaussian functions. Then we carefully discussed the geometrical feature of PU Vul in April 2004.

Single PPM Quality Innovation Movement is originally developed quality program in Korea for supplier's quality level-up since 1995. The quality target is below the 10ppm(parts per million) in outgoing quality and delivered goods plus field claim. Recently

In-situ processing route was adopted to disperse carbon nanotubes (CNTs) into powders homogeneously. The composite powders with homogeneous dispersion of CNTs could be synthesized by a catalytic route for in-situ formation of CNTs on nano-sized Fe dispersed powders. CNTs/Fe/ nanopowders were densified by spark plasma sintering (SPS). The hardness and bending strength as well as electrical conductivity increased with increasing sintering temperature. However, the electrical conductivity of the composites sintered at above showed decreased value with increasing sintering temperature due to the oxidation of CNTs

This paper considers a job shop environment where machines are shared by several sub-production systems. The local objective of a sub-production system is the minimization of total completion time. In a centralized environment, a single decision maker has complete information of processing time, job routing and local objectives. In this case, the problem is a traditional job shop scheduling problem to minimize the total completion time which is well-known NP-hard problem. Meanwhile, it is assumed that no sub-production system has a complete view of the entire system in a distributed environment. This paper proposes a distributed scheduling methodology that maintains autonomy of each sub-production system while pursuing system-wide performance in job shop environment. The proposed method is compared to the performance of centralized solutions.

This paper considers a single machine scheduling problem where the machine is shared by multiple sub-production systems. Each sub-production systems has heterogeneous local objectives (e.g., minimization of total completion time, maximum tardiness and makespan). In a distributed manufacturing environment, no sub-production system has complete information (e.g., processing time, due date) of the entire system. This paper provides a distributed scheduling method to find close-to-optimal coordination on the shared machine using minimum local information sharing among sub-production systems. The proposed method is compared to pareto solution that can be found in a centralized environment.

This research has been conducted in order to assess the effects on quality management factor of the construction sites. 30 companies abiding by the 'construction industry law' and 32 companies abiding by the 'housing construction promotion law' have been researched in areas of quality-management environment, quality-management understanding, quality-management education on construction field, quality-system and quality-improvement. This construction quality factors are to realized the anticipated results not only quality level's increasing, but also company's confidence, competitiveness. We were able to obtain participations of 62 questionnaire, and derived statistics by means of SPSS/PC version 10.0. In this study, we find the bottleneck factor for promotion and upgrade quality management factor of the construction sites and suggest a way out of difficulties.

Ultra-fine copper powders with particle size about 150 nm were synthesized from copper hydroxide slurry by wet method using hydrazine as reduction agent and several sur factants at below . The particle size distribution and dispersion of synthesized powders as function of temperature, feeding rate of reduction and especially, sur factants were character ized by XRD, BET, PSA and SEM by this process.