위암 환자에서 세포성 면역 기능에 관한 연구

이재익,윤일국,이종선,김종완,장준,안정기,송민호,정현용,이헌영,김삼용,김영건 충남대학교 암연구소 1991 癌共同硏究所 硏究誌 Vol.1 No.1

We performed a variety of lymphocyte stimulation tests, delayed hypersensitivity skin tests, and enumeration of several lymphocyte subpopulations in 21 patients with gastric cancer who did not receive any form of anticancer therapy, and in 20 healthy controls. The gastric cancer patients had significantly decreased number and total score of positive reactions in delayed hypersensitivity skin tests compared with the healthy controls. The percent of CD_(4) positive lymphocytes in the gastric cancer patients was significantly decreased compared to the normal control subjects, but it had no correlation with the total score of delayed cutaneous hypersensitivity reactions. The ratio of helper to suppressor cells was lower in the cancer group. The uptake of 3H-thymidine was markedly depressed in cancer patients when stimulated with various mitogens. There was little correlation between any of the stimulation tests and any of the lymphocyte subpopulation proportions to delayed hypersensitivity cutaneous reactions. Optimal proliferative response was found in lymphocytes stimulated with 10 micrograms of concanavalin-A and 10 microgram of phytohemagglutinin. Advanced stage patients had greatly depressed delayed hypersensitivity skin reactions and proliferative responses to mitogens compared with localized diseases. These results suggest that gastric cancer patients have depressed cellular immune functions, which mainly result from the decreased helper cells and defects in functional proliferative response to mitogens. Interleukin-2 and interferon-gamma restored the in vitro proliferative response of lymphocyte in patients with gastric cancer.

Rapid Consolidation of WC‑ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

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.

Characterization and Property Evaluation of Ti‑Based Target Materials and Their Nitride Nano‑composites Coating Layers

Jeong‑Han Lee,Hyun‑Kuk Park,장준호,Ik‑Hyun Oh 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed andrefined. The TiAlSi and TiAlSiW coating targets were fabricated using a pulse current activated sintering process in a shorttime with the optimal sintering conditions. The optimized sintering condition was obtained by controlling process parameterssuch as temperature, pressure, heating rate and pulse ratio (on/off). The coating targets were successfully deposited onthe WC substrate to form the TiAlSiN and TiAlSiWN nitride nano-composite structures by an arc ion plating process andalso, their coating layers were compared according to the addition of W element. The microstructures of the nitride nanocompositecoating layer were analyzed, focusing on the distribution of the crystalline phases, amorphous phases (Si3N4),and growth orientation of the columnar crystal depending on the addition of W element. The mechanical properties of thecoating layers were exhibited a hardness of approximately 3000 kg/mm2 and adhesion of about 117.77 N in the TiAlSiN. Inparticular, the TiAlSiWN showed excellent properties with a hardness of more than 4300 kg/mm2 and an adhesion of about181.47 N, respectively.

위암 환자에게 세포성 면역 기능에 관한 연구

이재익,윤일국,이종선,김종완,장준,안정기,송민호,정현용,이헌영,김상용,김영건 忠南大學校 癌共同硏究所 1991 癌共同硏究所 硏究誌 Vol.1991 No.-

Effect of Mechanical Alloying on the Microstructural Evolution of Al60Cr30Si10 Alloys Processed by Spark Plasma Sintering

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.

Influence of Phase Composition in TiAlSiN Hard Coatings on the Evolution of Structure and Mechanical Properties

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.

구내 절개법에 의한 악하선 적출

이국엽,진우정,백진아 大韓顎顔面成形再建外科學會 1994 Maxillofacial Plastic Reconstructive Surgery Vol.16 No.4

Surgical removal of the submandibular gland via intraoral approach was performed. The surgical procedure to be used for removal of submandibular gland had been performed via extraoral approach for many centuries. Disadvantages of extraoral technique are the esthetic distress due to an external scar, residual inflammation in Wharton's duct, and neurological complications. Indications of intraoral approach are unlimited in surgical cases of submandibular gland. Advantages of intraoral approach are esthetic satisfaction due to no remaining scars, preservation of adjacent anatomical structures and preservation of lower facial contour. This paper describes the surgical technique of the submandibular gland excision through an intraoral approach and variable incision lines tried. In 7 cases, excellentresults were obtained after removal of the submandibular gland through an intraoral approach.

CORBA기반의 미들웨어를 이용한 DBMS 통합 시스템의 설계 및 구현

이정훈,김영국 충남대학교 기초과학연구소 2001 忠南科學硏究誌 Vol.28 No.2

Database management systems(DBMS) are widely used in most of business information systems, but have various hardware and software platforms. It means that there are difficulties of developing applications which require to access existing multiple heterogeneous DBMS. Developers have to write different applications for each system environments and rebuild all applications whenever the system environment has changed. In this paper, we propose 3-tier system model based on the CORBA distributed object framework in order to solve the above problem and enhance the usability of existing codes. We demonstrate the usefulness of the proposal model by developing an integrated catalog-searching module in on-line shopping mall system and evaluated the system performance.

3채널법에 의한 1차원 진동인텐시티 측정수법에 관한 연구

이채봉,조형국,김정국,홍창희 東亞大學校 附設 情報通信硏究所 1994 情報通信硏究所論文誌 Vol.2 No.1

1차원 진동인텐시티의 측정은 원리적으로 4개의 센서를 이용하므로서 가능하다. 그러나, 4개의 센서를 이용하므로서 발생하는 오차의 영향을 무시할 수 없다. 만일 센서의 수를 줄일 수만 있다면 상대적으로 오차를 줄일 수 있다. 본 연구는 진동 field 를 半 near-field 라고 가정하였을 경우, 3階 미분항을 2階 미분항으로 나타낼 수 있음을 보였다. 2階 미분항으로 나타내었을 경우 3개의 센서로 측정하는 것이 가능하다. 3개의 센서로 진동인텐시티를 측정하였을 경우와 4채널법, 2채널법으로 각각 시뮬레이션을 하여 비교 검토하였다.

삼각측량 시스템을 이용한 물체의 3-D 정보추출 관한 연구

이호영,김국세,문정환,이철승,방극인,박영옥 조선대학교 전자정보통신연구소 2002 電子情報通信硏究所論文誌 Vol.5 No.2

The 3-D shape use to effect of movie, animation, industrial design, medical treatment service, education, engineering etc... But it is not easy to make 3-D shape from the information of 2-D image. There are two methods in restoring 3-D video image through 2-D image; First the method of using a laser; Second, the method of acquiring 3-D image through stereo vision. Instead of doing two methods with many difficulties, I study the method of simple 3-D image in this research paper. We present here a simple and efficient method, called direct calibration, which does not require any equations at all. The direct calibration procedure builds a lookup table(LUT) linking image and 3-D coordinates by a real 3-D triangulation system. The LUT is built by measuring the image coordinates of a grid of known 3-D points, and recording both image and world coordinates for each point; the depth values of all other visible points are obtained by interpolation.