바이러스 입자를 감지하는 역전사 핵산 연쇄 증폭법 (VC/RT-PCR)은 감염된 식물종들로부터 핵산 추출 없이 식물바이러스들을 검출 할 수 있다. 본 연구는 VC/RT-PCR 분석법을이용하여 고추를 감염시키는 바이러스들을 효과적으로 진단하기 위하여 새로운 즙액 추출 완충액들이 제작하였다.토마토반점위조바이러스 (Tomato spotted wilt virus;TSWV), 고추약한모틀바이러스 (Pepper mild mottle virus;PMMoV) 및 고추모틀바이러스 (Pepper mottle virus;PepMoV) 진단을 위한 가장 최적화된 추출 완충액은 0.5%sodium sulfate를 포함하는 1.0M Tris (pH 8.0) buffer 였다.고추 바이러스들은 담배 즙액 추출 후 7일까지 검출이 되었으며, 마쇄 직후와 검출 감도는 유의한 차이가 없었다. 반면에,3가지 고추 바이러스들은 고추 즙액 추출 후 2일까지만 바이러스들이 검출되었으며, 검출 감도는 크게 감소하였다.국내 고추 재배 농가들에서 수집한 고추 시료들에서 TSWV,PMMoV, PepMoV의 단독 감염 및 PMMoV와 PepMoV의중복 감염을 선발된 최적 즙액 완충액과 VC/RT-PCR의 조합을 이용하여 동시 진단이 가능하였다.

The knowledge of grain growth of carbide particles is very important for manufacturing micrograined cemented carbides. In the present study, continuous and discontinuous grain growth in WC-Co and WC-VC-Co cemented carbides is investigated using the Monte Carlo computer simulation technique. The Ostwald ripening process (solution/re-precipitation) and the grain boundary migration process are assumed in the simulation as the grain growth mechanism. The effects of liquid phase fraction, grain boundary energy and implanted coarse grain are examined. At higher liquid phase content, mass transfer via solid/liquid interfaces plays a major role in grain growth. Growth rate of the implanted grain was higher than that of the matrix grains through solution/re-precipitation and coalescence with neighboring grains. The results of these simulations qualitatively agree with experimental ones and suggest that distribution of liquid phase and carbide particle/carbide grain boundary energy as well as contamination by coarse grain are important factors controlling discontinuous grain growth in WC-Co and WC-VC-Co cemented carbides. The contamination by coarse grains must by avoided in the manufacturing process of fine grain cemented carbides, especially with low Co.

Anaerobic reductive dehalogenation of perchloroethene (PCE) was studied with lactate as the electron donor in a continuously stirred tank reactor (CSTR) inoculated with a mixed culture previously shown to dehalogenate vinyl chloride (VC). cis-1,2- dichloroethene (cDCE) was the dominant intermediate at relatively long cell retention times (〉56 days) and the electron acceptor to electron donor molar ratio (PCE:lactate) of 1:2. cDCE was transformed to VC completely at the PCE to lactate molar ratio of 1:4, and the final products of PCE dehalogenation were VC (80%) and ethene (20%). VC dehalogenation was inhibited by cDCE dehalogenation. Propionate produced from the fermentation of lactate might be used as electron donor for the dehalogenation. Batch experiments were performed to evaluate the effects of increased hydrogen, VC, and trichloroethene (TCE) on VC dehalogenation which is the rate-limiting step in PCE dehalogenation The addition of TCE increased the VC dehalogenaiton rate more than an increase in the H2 concentration, which suggests that the introduction of TCE induces the production of an enzyme that can comtabolize VC.

WC-10Co-0.8VC nanocrystalline powders were sintered by spark plasma sintering (SPS) and hot press sintering (HPS), and the microstructure and properties were compared. Results show that dense WC-10Co-0.8VC can be obtained by SPS in several minutes when the sintering temperature is >1200℃. Sintered at a temperature of 1300℃, the sample prepared by SPS for 3 minutes has higher density, finer grains and better properties than that prepared by HPS for 60 minutes. SPS can be used to prepare nanocrystalline WC-10Co-0.8VC with improved properties when suitable sintering parametesr are chosen.

WC/WC interface in VC mono-doped WC-10mass%Co submicro-grained hardmetals of was investigated together with WC/Co interface by using HRTEM and XMA. The thickness of V-rich layer and the analytical value of V at WC/WC interface were almost the same as those at WC/Co interfaces. These results, etc., suggested that the V-rich layers at both interfaces were not generated by an equilibrium segregation mechanism in the sintering stage, but generated by a preferential precipitation mechanism during the solidification of Co liquid phase in the cooling stage. Based on this suggestion, we succeeded in developing a nano-grained hardmetal with 100 nm .

One append way of liquid state inhibitor was investigated, which putting V, Cr into W-Co composite solutions in the form of ionization. After spray drying and being calcined, W-Co composite oxides could come into being. Then taking fluidization techniques, well-proportioned W-Co composite powder compounded with inhibitor could be produced in the end.

In this study, the WC-10 wt.%Co nanopowders doped by grain growth inhibiter were produced by three different methods based on the spray conversion process. Agglomerated powders with homeogenous distribution of alloying elements and with internal particles of about 100-200 nm in diameter were synthesized. The microstructural changes and sintering behavior of hardmetal compacts were compared with doping method and sintering conditions. The microstructure of hardmetals was very sensitive to doping methods of inhibitor. Nanostructured WC-Co hardmetal powder compacts containing TaC/VC doped by chemical method instead of ball-milling shown superior sintering densification, and the microstructure maintained ultrafine scale with rounded WC particles.

Cobalt and VC powders were ball milled with M2 grade high speed steel powders under various ball to powder ratios. The powders milled under higher ball to powder ratio become finer, more irregular and have a broader size distribution, and thus possess a lower compressibility and a better sinterability regarding densification. Increasing the ball to powder ratio lowered the sintering temperature to obtain the density level necessary to isolate all the pores. Lowering the sintering temperature is very critical to maintain fine microstructure since grain and carbide coarsening are accelerated by higher sintering temperature due to more liquid phase formation. The powders obtained by ball milling at 20 to 1 ratio has the lowest compressibility but has the best sinterability, almost compatible to unmilled pure M2 powders. A sintered body over 97% theoretical density with fine microstructures having average grain size of ~10 microns was obtained from the powder by sintering at 1260 for 1 hour in vacuum. XRD results indicate that two types of carbides are mainly present in the sintered structure, MC and type. The MC type carbides are more or less round shaped and mainly located at the grain boundaries whereas the type are angular shaped and mainly located inside the grains.