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Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3
The aim of this study is to investigate the structural evolution and mechanical properties of TiAlSiN coatings when processedby the arc ion plating method. To form a hard coating, Ti, Al, and Si powders were mechanically alloyed by planetary ballmilling; the powders were then densely compacted during a rapid sintering process into a ternary system coating, i.e. TiAlSi. The evolution of the structural phase from a powder to a compact material is dominated considerably by phase states suchas a supersaturated solid solution or intermetallic compounds. In the case of coating layers, the factors that determine thestructural evolution are associated with the phase stability of the nano-crystalline structure that in turn is associated withthe Ti/Al composition ratio. Motivated by this, we performed experiments to investigate the distribution of microstructures;the material’s binding energy, quantitative properties, transformation of crystal structure, and distribution of amorphous/crystalline were all recorded. In particular, the relationship between the physical and chemical properties during the coatingprocess is considered to be the dominant factor controlling the orientation and morphology of that zone (1, T, and 2). TheTiAlSiN coating layer was found to have hardness above 45 GPa and an adhesion above 100 N. In other words, understandingthe evolution and structure of TiAlSin helped us to produce a material with excellent properties that can be used as a hardcoating. Specifically, these properties were induced by a grain refinement of the nano-crystalline structure that correspondsto an increase in the silicon nitride contents.
Jeong‑Han Lee,Ik‑Hyun Oh,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9
Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4was fabricated by spark plasma sintering at 1400 ℃ ata constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried outfor 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. Itwas observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents,and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact wasfound to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical propertiesof the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to thepresence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zirconfrom a transgranular to a ductile component (fcc) where the crack tips could be absorbed.
Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5
In this study, Al, Cr and Si fine powders were alloyed by planetary ball milling to investigate their microstructural evolution,following their mechanical alloying behavior. The formation of Al(Cr) supersaturated solid solution by the Cr grainsembedded in Al-matrix, which contributed substitutional structure is discussed in relation to their structural evolution inaccordance with the distortion of a crystal lattice. The compacts of Al–Cr–Si alloys were prepared by rapid sintering withina short time by dense consolidation above the density of 99.9% as the formation of intermetallics, except in the case of thedistribution of single-phases induced by the Al-melting. The formation behavior of intermetallics was dominated by dependenceon the structures of the milled-powder and subsequent sintering temperature. To estimate the consolidated behaviorsof compacts, various approaches derived from TEM and XRD analysis were taken to obtain microstructural evidences ofthe inter-diffusion, following the presence of thermally stable intermetallics.
제어 시스템 설계를 위한 IEC 1131-3 기반의 제어 로직 생성기의 개발
정구,심주현,이제필,이철수 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-
This paper describes the methodology of an IEC 1131-3-based control logic generator for the control system design and converting algorithm between programmable languages. The proposed control logic generator is generated based on the software model and common element with data type, variables, POUs(program organization unit) and execution control unit commonly used within programmable languages of IEC 1131-3 Standard. The generation method of object file was proposed on five programmable language based on IEC1131-3. The generation method of object file is represented as following; 1) the generation method using conversion algorithm from LD to IL with FBD(function block diagram), 2) the generation method using C code generation algorithm from SFC using the SFC execution sequence with FBD and ST(structured text). The proposed control logic generator was implemented by Visual C++ and MFC on MS-windows NT 4.0
상부소환관협착에 대한 Savary-Gilliard Dilatation의 치료효과와 안전성에 관한 관찰
정현용,육은주,임의혁,김병호,성자원,이기천,허승식,이헌영,김영건 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.2
For the patient with stenosis of upper digestive tract caused by either benign or malignant process, esophageal dilatation is an important therapeutic modality. We reviewed retrospectively 39 cases treated by Savary-Gilliard dilatation for upper digestive tract stenosis, and results were follows : (1) Dysphagia was improved in 95% of the patients. (2) Eight patients(20%) sufferd perforation, five of them were managed with conservative medical measures, others were managed operatively. (3) In the cases with benign stenosis dysphagia was not noticed for 8.8 months, but with malignant stenosis dysphagia was reappeared after 2.8 months despite concomitant chemoradiotherapy. In conclusion, Savary-Gilliard dilatation was an effective measure for symptome due to upper digestive tract stenosis, but more careful attention for perforation should be necessitated. Also another therapeutic modality for treatment of malignant stenosis was inevitable.
鄭宰顯,崔元碩,曺柱鉉 충주대 2004 産業科學論文集 Vol.12 No.-
This research to develop a functional food by using higher fungi from white ginseng, investigated the higher fungi using with ginseng media, the optimal culture conditions of the solid culture and the consistent of solid-product cultured. The results obtained were as follow; 1. Hericium erinaceum, Phellinus linteus and Ganoderma lucidum were observable the growth which is most excellent among 14 strains of the higher fungi using substrate with ginseng residue extract, therefore, it were used for the breed strain. 2. The optimal culture conditions of the solid culture for mycelial growth of Hericium erinaceum, Phellinus linteus and Ganoderma lucidum were added 10%(w/w) of nutrient material as brown rice etc. supplement for maximum mycelial growth. 3. The Ginseng-H. erinaceum (Ginseng-P. linteus, Ginseng-G. lucidum) solid-product cultured under these conditions consisted that were moisture of 3.5%(3.5, 3.6), crude proteins of 7.65%(9.22, 13.57), crude lipid of 8.79%(4.66, 12.02), ash of 9.86%(8.27, 13.38) and carbohydrate of 70.246%(74.33, 57.43).
성견 치은에서 90% Phenol을 이용한 멜라닌 색소의 제거에 관한 연구
정태술,김영준,이영규,정현주 전남대학교 치의학연구소 2001 구강과학 Vol.13 No.4
In this present study, the healing process and the recurrence of pigmentation were evaluated clinically and histologically in accordance with the extent and the range of pigmentation after phenol was applied to remove melanin pigmentation in gingiva. Six mongrel dogs were used. The melanin pigmentation in canine gingiva were classified into slight, moderate, and severe according to the extent of pigmentation and divided into local and diffuse types according to the range. Following general and local anesthesia, 90% phenol was applied to the pigmented gingiva of the subjects with small cotton balls until the surface was etched to be whitish and was neutralized with small cotton balls soaked by 95% alcohol. The contralateral pigmented gingiva to the one treated with phenol, was treated by surgical deepithelialization. At1, 3, and 8 weeks, the treated gingiva was examined clinically and evaluated histologically following H-E stain, and HMB 45 stain for melanocyte after biopsy. In the phenol treated sites, epithelium and connective tissue healed normally and there was no pigmentation at 1 week. At 3 weeks of healing, melanin repigmentation was observed in the severe local type and moderate to severe diffuse type. In the surgically deepithelialized sites, healing was delayed, compared to phenol treated sites and the infiltration of the inflammatory cells and congestion in connective tissue was shown at 1 week. At 3 weeks, healing was completed and there was a partial melanin repigmentation. At 8 weeks of healing, the extent and the range of repigmentation were increased in both group according to the extent or range priot to depigmentation procedure. These results suggest that the removal of melanin pigmentation with 90% phenol application result in normal healing process of gingiva. However, in the severe local type and moderate to severe diffuse type, sites treated with phenol showed repigmentation at 3 week, which was earlier than surgical deepithelialized sites. Therefore it is required to select appropriate method according to initial condition of pigmentation.
성견의 외과적 치근이개부 골결손에 차폐막과 골이식재를 이용한 조직유도재생술시 치유양상
정은희,정현주 전남대학교 치과대학 1996 전남치대논문집 Vol.8 No.1
The present study was to evaluate the healing patterns of guided tissue regeneration(GTR) using resorbable Vicry??(polyglactin 910) mesh and nonresorbable expanded polytetrafluoroethylene(ePTFE) membrane with or without bone grafting using autogeneous bone and demineralized freeze-dried bone allograft(DFDBA) in the grade Ⅱ furcation defects. Mucoperiosteal flaps were reflected buccally in the mandibular 2nd, 3rd and 4th premolar areas and furcation defects were created surgically by removing 5 × 6mm alveolar bone in 4 dogs. Root surfaces were thoroughly debrided of periodontal ligament and cementum, and notches were placed on root sruface at the most apical bone level. In the right and left mandibular quadrant, each tooth was received Vicryl?? mesh(ACE Surgical Supply Co., USA) only, Vicryl?? mesh with DFDBA, Vicryl?? mesh with autogeneous bone grafts, ePTFE membrane(Gore-tex?? membrane, W.L. Gore & Associates Inc., USA) only, ePTFE membrane with DFDBA or ePTFE membrane with autogeneous bone grafts. For the fluorescent microscopic examination, fluorescent agents were injected at 2, 4 and 8 weeks after surgery. Four weeks after surgery, 2 dogs were sacrificed and ePTFE membranes were removed from remaining 2 dogs, which were sacrificed at 12 weeks after surgery. Undecalcified tissues were embedded in cethylmethacrylate and 10㎛ thick sections were cut in a buccolingual direction. These sections were stained with hematoxylin-eosin stain and Masson's trichrome stain, and evaluated by descriptive histology and linear measurements. The results were as follows : 1) Vicryl?? mesh group showed less connective tissue attachment than ePTFE membrane group. 2) The combination of GTR using Vicryl?? mesh and osseous grafts resulted in new attachment and new bone formation more than GTR using Vicryl?? mesh only. 3) GTR using ePTFE membrane, with or without osseous grafts, enhanced periodontal regeneration. 4) Root resorption and dentoalveolar ankylosis were observed in the areas treated with the combination of GTR and DFDBA. It was suggested that the effect of adjunctive bone grafting in GTR procedure depends on the materials and the physical properties of barrier membranes. Vicryl?? mesh performed a barrier function and the use of adjunctive bone grafting may enhance the periodontal regeneration.