纖維强化 Plastics의 切削加工에 관한 硏究

金元鎰,李允景,姜渭民 慶南大學校 附設 工業技術硏究所 1991 硏究論文集 Vol.9 No.-

本 硏究에서는 유리纖維 强化樹脂의 旋消時 각 切削 條件에 따른 超音波 振動切削과 常用切削時 나타나는 加工特性을 考察하기 위하여 眞圓度, 表面粗度을 中心으로 比較, 檢討한 結果 다음과 같은 結論을 얻을 수 있었다. 1. 眞圓度의 값은 切削條件 및 振幅에는 많은 影響을 받지 않고, 纖維角이 60˚인 경우 V=60m/min, f=0.08mm/rev, t=0.05mm일때 眞圓度 값이 10㎛로 가장 良好하였고, 纖維角이 90˚인 경우에는 振動切削에서는 19㎛, 常用切削에서는 37㎛로 가장 높은 값이 나타났으며, 振動切削이 常用切削 보다 약 2배 改善되었다. 2. 表面眺度는 纖維角이 60˚인 경우가 가장 良好하고, V=20m/min에서는 振動切削과 常用切削의 값은 거의 變化가 없으며 V=30m/min이상에서는 振動切削이 顯著하게 改善되었다. 3. 工具傾斜角은 眞圓度에는 많은 影響을 미치지 않지만 表面粗度는 0˚보다 6˚가 약간 改善됨을 알 수 있다. 4. 振動切削은 硏削에서 얻을 수 있는 加工精度를 旋削에서도 쉽게 얻을 수 있어 精密度와 生産性을 向上시키는 加工法이라 할 수 있다. In this paper, under different cutting condition on G.F.R.P, ultrasonic vibration cutting and the characteristics in conventional cutting have been studied. So the following conclusion centered on comparison, examination of roundess, surface roughness has been reached. 1. The value of surface roundess doesn't get much effect from amplitude as well as cutting conditions. With 60˚of fiber angle, v=60m/min, f=0.08mm/rev, t=0.05mm, the value of surface roundess, 10㎛, was the best. In case of 90˚, the highest value was 19㎛ in vibration cutting and 37㎛ in conventional cutting vibration cutting has improved about twice as high as conventional cutting. 2. In case the fiber angle was 60˚, surface roundess was little difference between vibeation and conventional cutting. Under v=30m/min and above, vibration cutting has remarkably improved. 3. Even if the tool rake angle doesn't affect the roundess, surface roughness has improved a little more at 6˚than at 0˚. 4. Vibration cutting helps to gain as lathe turing working precision as in grinding, Consequently, it's considered a good working method to improve precision and productivity.

超硬 切斷工具 刃先의 應力分布 解析에 관한 硏究 (I)

李允景,金元鎰 慶南大學校 附設 工業技術硏究所 1987 硏究論文集 Vol.5 No.-

旋削에 의한 超硬 切斷工具의 傾斜面 應力 變形率 分布에 대한 靜剛性 解析을 한 結果 다음과 같은 結論을 얻었다. 切斷加工에서 切削깊이 方向의 切削速度 變化는 切削力에 큰 영향을 주지 않으며, 切削條件에 의한 應力, 變形率 變化는 移送이 클수록 크고 接觸길이 0.3㎜ 정도에서 應力 값이 크게 減少하므로 칩핑 가능성이 높다. 應力 및 變形率의 變化幅이 큰 것은 切削에 있어서 摩擦의 狀態가 칩 傾斜面 接觸길이 部分에서 一定하지 않는다는 것을 알았다. In the turning, Analyses of the static deformation relating to the destributions of stress and strain on a rake face of cemented carbide parting tool have obtained results which are as follows, 1. In the parting work, the change of cutting speed relating to cutting depth and direction has been greatly uneffected cutting force. 2. As feed grows larger, the change of stress and strain under cutting conditions grows larger, and the value of stress decreases greatly in the near contect length of 0.3㎜. therefore, It is highly possible thet chipping occurs. 3. In the cutting, the changed value of strain and stress which is large have been not uniformed the state of friction in the near contect length of Chip-rake face.

오스테나이트系 스테인레스鋼의 熔接 入熱이 殘留應力과 收縮.變形量에 미치는 影響에 관한 硏究

李允景,金治遠 慶南大學校 附設 工業技術硏究所 1992 硏究論文集 Vol.10 No.-

오스테나이트系 스테인레스鋼(STS 304)은 여러가지 長點으로 인해 高級 製品의 素材로 각광을 받고 있는 반면에 또한 一般炭素鋼에 비해 낮은 熱傳導率과 큰 熱膨脹係數 때문에 鎔接施工時에 鎔接入熱에 의해 殘留應力 및 收縮, 變形量의 影響이 크게 나타난다. 이런 鎔接 施工上의 애로를 最少化하기 위해 鎔接入熱에 의해 殘留應力과 收縮 및 變形量에 대해서 검토하였다. Recently, the use of Austenite Stainless Steel has been increasing in wide applications, such as pressure vessels, heat excahngers for chemical plants, and especially component material of nuclear power plants, due to the good characteristics of high anti-corrosion, beautiful external appearance. richful dutility and high heat-resistance. etc. However, many difficulties have been encountered in the field welding and fabrication, because of the large residual stresses and shrinkage-deformations due to the heat-input during welding caused by the very low heattransfer compared with that of general carbon steel. In order to assist for the reduction of these quality problems, this study demonstrates the relationship between residual stresses and shrinkage-deformations caused by the heat-input of several typical welding processes and types of joint for Austenite Stainless Steel(STS304). And, for improving quality and satisfactory welding during field fabrication, the results of this experimental study for minimizing the residual stresses and shrinkage-deformations due to weld heat-input.

원통 연삭에서 가공 능률 향상을 위한 연삭 저항의 측정에 관한 연구

김원일,이진,이윤경,왕덕현,이상복,이관철,문원길 경남대학교 공업기술연구소 2000 硏究論文集 Vol.18 No.-

본 연구에서는 원통 연삭 가공에서 가공 능률 향상을 위한 연삭 저항을 측정하고자 연삭 가공 중에 발생하는 연삭 저항의 추이를 확인하였고 다음과 같은 결과를 얻었다. 숫돌과 공작물간의 연삭 강성은 공작 속도의 증가에 따라 지지계의 강성이 높은 경우 증가하였고 절삭 깊이와 연삭 숫돌의 속도에는 연삭 강성이 감소하는 경향을 보였다. 또한 총합 강성은 공작 속도, 절삭 깊이 및 연삭 숫돌의 속도 증가에 따라 지지계의 강성이 높을 수록 증가하였다. 연삭기의 강성 변형과 가공 능률에 영향을 주는 값으로 연삭 강성비는 지지계의 강성이 높을 수록 감소하였다. In this study, the measurement of grinding resistance to improve grinding efficiency in cylindrical grinding was studied and the following conclusions could be obtained. Relation grinding wheel and workpiece, grinding stiffness increases according to increase of work speed for high machine stiffness and decreases depth of cut and grinding wheel speed. Also, resultant stiffness increases high machine stiffness according to increase work speed, depth of cut and grinding wheel speed. The values of the effect stiffness deflection in grinding machine, grinding stiffness ratio decrease according to high machine stiffness.

논토양중 카드뮴 유효도와 수도의 흡수이행에 미치는 석회 및 Humic acid 사용효과

김민경,김원일,정구복,박광래,윤순강,엄기철 한국환경농학회 2004 한국환경농학회지 Vol.23 No.1

토양중 중금속이 식물에 흡수 및 이행되는 것을 경감시켜 여기에서 생산된 농산물의 안전성 향상을 위한 기초자료를 확보하고 논토양의 카드뮴 유효도와 흡수이행에 미치는 석회와 humic acid 처리 효과를 구명하기 위하여 실내경험과 포트실험을 수행하였다. 실내실험에서 공시토양에 2.5와 5.0 ton/ha의 석회와 1%와 2% humic acid를 처리한 후 토양중 가용성 카드뮴 함량 변화를 조사한 결과, 두 처리 모두 14일까지는 담수상태에서 처리효과로 인하여 가용성 카드뮴 함량이 감소하다가 그 이후에는 토양의 완충능에 의해 다시 증가하는 경향이었다. 이때, 토양의 가용성 카드뮴 함량은 토양 pH 및 양이온치환용량과 부의 상관이 있었다. 2.5 ton/ha의 석회와 1% 의 humic acid를 처리한 후 담수시켜 안정화된 다음 벼를 재배하여 조사한 결과, 석회와 humic acid 처리에 비해 분얼기와 수확기의 치화태 및 수용태 카드뮴 함량이 낮아졌으나, 분얼기에 비해 수확기에 토양중 이동이 어려운 산화물 및 탄산염태와 황화물 및 잔류태의 함량이 증가하였다. 식물에 흡수가 용이한 형태로 알려진 치환태와 수용태는 모두 토양 pH와 고도의 부의 상관이 있었다. 수확기의 줄기, 잎 및 현미 건물중은 석회 및 humic acide 처리구에서 대조구에 비해 모두 높았고, 특히 석회 처리구의 건물중이 현저하게 높았다. 석회 처리구에서 줄기와 잎의 카드뮴 함량은 각각 1.01과 0.37㎎/㎏으로 대조구와 비슷하였으나, 뿌리나 현미의 카드뮴 ?량은 각각 2.11과 0.09㎎/㎏으로 대조구에 비해 낮았다. 지상부와 뿌리의 카드뮴 함량은 humic acid 처리에 의해 현저히 낮아졌으며, 특히 현미로의 카드뮴 이행도 월등히 낮게 나타난다. This study was conducted to know the effect of lime and humic acid on cadmium availability and its uptake by plant grown in contaminated paddy soils with heavy metal. The treatment levels of lime were 2.5 and 5.0 ton/ha and that of humic acid were 1 and 2%. The contents of 0.1 N HCl extractable Cd were reduced with lime and humic acid and were negatively correlated with CEC as well as soil pH. The sequential extraction procedure was used to fractionate the heavy metals in soil into the designated from exchangeable (0.5 M KNO₃), water soluble (H₂O), organically bound (0.5 M NaOH), carbonate (0.05 M Na₂-EDTA) and sulfide/residual (4 M HNO₃). In soil amended with 2.5 ton/ha lime and 1% humic acid, chemical forms of Cd at tillering stage were predominant exchangeable+water soluble extractable Cd, whereas that at harvesting stage were predominant carbonate+sulfide/residual extractable Cd. The exchangeable forms of Cd in soil with lime and humic acid were negatively correlated with soil pH during the harvesting period. Total absorbed Cd of paddy rice tended to occur in the order of root > stem > leaf > brown rice. Cd con- tents of brown rice with lime and humic acid treatment were 0.09 and 0.08 mg/kg, respectively. That were lower than control, 0.20 ㎎/㎏. It could be that treatment of lime and humic acid in polluted soil by heavy metals would reduce the uptake of heavy metals by plants and be a temporary method of reclamation at the highly heavy metal contaminated soils.

斷續切削時 超硬工具의 缺損에 관한 硏究

李允景,金元鎰 경남대학교 신소재연구소 1991 論文集 Vol.1 No.-

본 연구의 목적은 기계적 충격에 의한 절단희수의 실험치를 F.W.Taylor의 공구수명방정식을 근거로 하여 절단희수에 대한 확장된 공국수명식을 유도하여 구한 이론치와 비교 하였다. 또한, 공구형상에 대하여 주축회전속도, 이송을 변화시켜 절삭저항 및 절단희수와의 관계를 실험적으로 검토하였으며 결손형태를 공구현미경으로 관찰, 확인하여 최적 가공 조건을 찾고자 함에 있다. 단속절삭의 절단가공식 절단회수를 가장 많이 할 수 있는 최적 절삭조건은 흠이 2개월 경우 510 rpm, 이송 0.052mm/rev, 공구의 최적 형상은 KTP 43-3type(경사각 6°)이었고, 흠이 4개일 경우 396 rpm, 이송 0.052 mm/rev, 공구의 최적 형상은 KTP 43-4type (경사각 6°)이었다. The purpose of this study is investigates the breakage of carbide tools cause to mechanical impact in the intermittent cutting. For this purpose, the cutting speed and the feed rate was took variable for the type of cutting-off tool. First, delieve the tool life equation for flank wear and compared to the theoretical value, and Second, investigates the tool breakage according to the number of impact of the tool, and then find the tool type and the best condition of cutting procedure. Form the experiments, we know that the breakage of cutting tool was increases excessivly with increases of feed rates. Therefore, we know that the excessiv mechnaical impact would avoided when the intermittent cutting to non-machinabiltiy cutting object like carbon steel and choose the tool width, spindle rpm and feed rates well. Form the conclusions, tool breackage occurrence tiny when cut-off turning, and the optimum cutting conditions for the maximum number of pass are N=500rpm, f=0.157mm/rev, the optium geometry of the tool is KTP 43-3 type (rake angle 6°) with two grooves, and N=395rpm, f=0.052mm/rev, the optimum geometry of the tool is KTP 43-4 type (rake angle 6°)with four grooves.

전자기식 센서의 용접선 검출 특성에 관한 연구

김원일,이윤경,우성문,최상봉 경남대학교 신소재연구소 1997 論文集 Vol.8 No.-

본 논문은 전자기식 센서의 용접선 검출 특성에 관한 연구이다. 센서의 검출 성능에 영향을 미치는 설계 인자를 실험을 통하여 결정하고 센서를 제작하였다. 제작된 와전류식 전자기 센서를 용접선에 가로지르는 방향으로 주사하여 센서의 용접선 검출능력을 확인하였다. 그리고, 냉간 압연강판 및 스테인레스 스틸, 알루미늄, 구리와 같은 다양한 재료에 대해 용접선 검출 능력을 확인한 결과 냉간 압연강판에서의 검출 능력은 가장 양호하게 나타났고 고합금강 및 비철금속에 대해서도 용접선 검출 가능성을 확인하였다. 또한, 높이 방향 제어용 센서로써의 가능성도 확인하였다. This study is a work on weld line detecting characteristriic of electromagnetic sensor arc welding. Design parameters which effect on sensor performance were determined by experiments. Then a proper electromagenetic sensor of eddy current type was made by using the determined design parameters. Detecting ability of weld line on butt joint in sheet metal was confirmed by scanning the sensor across the weld line. Experiments were also performed on a variety of materials as cold rolled steel, stainless steel, aluminum, and copper and the detecting abilities were compared with each other. Experimental results have shown that the detecting ability on butt joint of sheet metal is good and the sensor can also be used for height control.

뇌졸중 위험인자를 가진 어지럼 환자에서의 확산강조 자기공명영상

강형구,윤유상,이진희,박인철,이경룡,정상원,구홍두,김승호 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: The management of vertiginous patients is a great challenge to emergency physicians. We evaluated the diagnostic value of a diffusion-weighted image(DWI) in differentiating central vertigo from the peripheral vertigo in patients who presented no neurological symptoms other than risk factors for stroke. Methods: From March 2000 to February 2001, we retrospectively analyzed the cases of 68 patients who visited the emergency department with symptoms of isolated vertigo and who had risk factors for stroke. DWIs, computed tomograms(CT), and medical records were reviewed, and the final diagnose, the DWIs and the CT readings, the risk factors for stroke, and the time it took waiting for a DWI or CT scan were analyzed. Results: Of the 68 patients, 21(30.8%) had central vertigo: 15 vertebrobasilar transient ischemic attacks(VB-TIA), 4 brain stem infarctions, 1 cerebellar infarction, and 1 cerebellopeduncular infarction. The DWI showed a 28.6% sensitivity, a 97.9% specificity, and an 85.7% positive predictive value in diagnosing central vertigo. It also had a 100% sensitivity in detecting infarctions. Conclusion: A DWI had a comparable sensitivity to MRI in detecting central vertigo and small, but potentially, lethal infarctions in our patient population. We recommend clinical application of DWI in the emergency department evaluation of isolated vertigo patients with risk factors for stroke.

Behcet 환자에 합병된 우측 쇄골하동맥 가성동맥류에서의 경피적 Stent-Graft 삽입술 1례 : 증례보고

김대경,윤영섭,최승혁,이동일,이도연,장병철,심원흠 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.11

扶餘 九龍川流域의 生態學的 特性에 對하여

任良宰,尹敬源 中央大學校 自然科學硏究所 1987 自然科學硏究所 論文集 Vol.1 No.-

The terrestrial and aquatic ecosystem of Guryong stream basin, the tributary of Geum-river, was investigated from July 1984 through September 1985. The basin(167.85㎢) is characterized by the land use with cultivated area(54.57%), secondery forest(20.24%), plantation(19.59%) and others, and by the topography with the 49.90%) lowland (0-50m in altitude), of whole area. The climate of the basin was evaluated with the warmth index(WI) of 78.65〈WI〈99.20℃·month and the mositure index(Im) of 100〉Im〉20. The annual total run-off was estimated as 20.42×??, 12.30×?? and 8.14×?? tons, respectively, by the Thornthwaite's water balanec sheet application. By the Z-M method five plant communities and three plantations were recognized as follows : Quercus serrata-Carpinus laxiflora, Quercus acutissima, pinus densiflora-Prunus sargentii-Styrax japomica, Ponica densiflora and Quercus dentata community and Pinus rigidda, Larix leptolepis and Castanea crenata plantation. The soil conditions such as the water content, PH, organic matter content and C/N ratio of soils showed some characteristics influenced by different vegetation types. The water qualities of, the stream such sa water temperature, pH, DO,BOD, NH₃,K, Mg and Na content, especially, the water acidity of the stream was remarkably influenced. by the soil acidity of land area and the disolved oxygen of the stream by the amount of run-off. It is clear that the environmental changes of the basin is largely enforced by the transformation of topography in lowland, a marsh area to rice field, human activities of the human population of 42,576 persons ranging 10 persons/㎢(in 300-350m elevation) to 297. 61 persons/㎢(in 0-50m) and the agricultural chemicals practice of Ca. 69.719㎏/ yr in cutivated area.