• 제목/요약/키워드: Maximum Cutting Temperature

검색결과 45건 처리시간 0.034초

후판용접부의 잔류응력과 횡균열의 상관관계 (The relationship between residual stresses and transverse weld cracks in the plate)

  • 이해우;강성원;박종진
    • 대한용접접합학회:학술대회논문집
    • /
    • 대한용접접합학회 2003년도 춘계학술발표대회 개요집
    • /
    • pp.263-265
    • /
    • 2003
  • The transverse crack, a type of cold crack, occurs perpendicular to the axis of the weld interface, longitudinal residual stresses ($\sigma$k direction) are more important in transverse crack occurrence from my own experience. Specimens were fabricated and welded under actual construction conditions, and then residual stresses of longitudinal stresses were measured for different welding conditions with SAW and FCAW process. The residual stress values for the specimen welded Interpass temperature below 30$^{\circ}C$ was higher than the specimen welded interpass temperature of 100~120$^{\circ}C$. And also the residual stress values for a specimen measured at weld surface, as welded condition, was higher than that of longitudinal residual stresses that was measured from a small test piece, due to the residual stress was relieved in the process of the cutting and machining. Transverse weld cracks were detected in the area of the maximum residual stresses both SAW and FCAW process.

  • PDF

콩의 취반속도에 미치는 온도의 영향 (Effect of Temperature on Cooking Rate of Soybean)

  • 김성곤;조광호;김종군
    • 한국식품과학회지
    • /
    • 제18권5호
    • /
    • pp.372-375
    • /
    • 1986
  • 콩을 $106^{\circ}{\sim}121^{\circ}C$의 가압조건에서 일정시간 조리하면서 최대 절단력을 측정하고 이로부터 조리속도를 계산하였다. 콩의 조리속도는 1 차반응의 속도로 표시될 수 있었으며 반응속도상 수는 조리온도가 4 또는 $5^{\circ}C$ 상승함에 따라 약 2배 정도 증가하였다. 동일한 조리도를 나타내는 온도-시간과의 관계로부터 계산한 콩의 연화에 따른 Z-값은 $13.3^{\circ}C$ 이었다.

  • PDF

Italian ryegrass의 추계예취시기가 목초의 재생 , 탄수화물축적 및 건물수량에 미치는 영향 (Effect of the Autumnal Cutting Times on the Regrowth , Accumulation of Carbohydrate and Dry Matter Yield of Italian ryegrass ( Loium multiflorum ))

  • 안계수
    • 한국초지조사료학회지
    • /
    • 제5권1호
    • /
    • pp.13-21
    • /
    • 1985
  • 본(本) 시험(試驗)은 추파(秋播) 이탈리안라이그라스의 추계예취시취(秋季刈取時取)가 목초(牧草)의 재생(再生), 탄수화물축적(炭水化物蓄積) 및 건물수량(乾物收量)에 미치는 영향을 구명(究明)하기 위(爲)하여 포장시험(圃場試驗)을 수행(遂行)하였으며 결과(結果)를 요약(要約)하면 다음과 같다. 1. 건물수량(乾物收量)은 예취시기(刈取時期)가 빠른 구(區)일수록 높았고(P<0.05), 예취시기(刈取時期)가 제일 늦은 구(區)는 무예취구(無刈取區) 보다도 수량(收量)이 낮았다. 2. 건물중(乾物中) 전수용성탄수화물(全水溶性炭水化物)(TSC)의 함량(含量)은 일번예취직후(一番刈取直後)에 약간(若干) 떨어졌다가 재생장(再生長)에 따라 점점(漸漸) 높아졌으며 이번초(二番草) 예취기(刈取期)에 가까울수록 다시 떨어졌다. 기온(氣溫)이 영하(零下)로 하강(下降)하기 1주일전(週日前)의 TSC 함량수준(含量水準)은 그루터기, 줄기, 잎 별(別)로 모두 예취시기(刈取時期)간 빠른 구(區)일수록 고수준(高水準)이었으며 (P<0.01), 이번초(二番草)와 건물수량(乾物收量)과의 사이에 상관(相關)이 성립(成立)되었다(P<0.05) 3. 개체군(個體群) 생장속도(生長速度)(CGR)는 평균기온(平均氣溫)이 $8^{\circ}C$에서 하강(下降)할수록 떨어졌으며 상승(上昇)할수록 높았다. 상대엽면적생장율(相對葉面積生長率)(RLGR)과 순동화율(純同化率)(NAR)은 각구(各區) 모두 재생(再生)30일간(日間)이 가장 높았으며 재생후기(再生後期)에는 저하(低下)되었다. 엽면적지수(葉面積指數)(LAI)의 증대(增大)는 각구(各區) 모두 예취후(刈取後) 50일(日)까지는 빨랐으며 그 후(後)에는 완만하였고 최대치(最大値)의 범위(範圍)는 $3.4{\sim}5.8$이었다. 또한 예취후(刈取後) 70일(日)까지의 LAI가 큰 구(區)일수록 이번초(二番草)의 건물수량(乾物收量)이 높았다. 4. 생장(生長)이 억제(抑制)되는 저온기(低溫期)의 TSC, LAI ,CGR, NAR 및 LWR와 이번초건물수량(二番草乾物收量)과의 사이에 상관(相關)이 인정(認定)되엇으며, 그 공헌도(貢獻度)는 LWR>LAI>TSC>NAR>CGR의 순(順)이었다.

  • PDF

치과용 지르코니아 블록의 소결온도가 기계적 특성과 미세구조에 미치는 영향 (The Effects of Sintering Temperature Influence on the Mechanical Property and Microstructure of Dental Zirconia Block)

  • 조준호;서정일;배원태
    • 대한치과기공학회지
    • /
    • 제36권1호
    • /
    • pp.9-15
    • /
    • 2014
  • Purpose: Generally dental technicians clinically decide the sintering temperature of zirconia artificial teeth to match the color of the teeth. However, the sintering temperature influence the microstructure and mechanical strength of ceramic body. In this study, to evaluate the free choice of sintering temperature which leads to color the problems in zirconia false teeth, the variation of microstructure, mechanical strength, and colortone of zirconia ceramics according to the change of sintering temperature was investigated. Methods: Bar type specimens were prepared from commercial zirconia blocks by cutting and polishing into $0.8cm(L){\times}1.0cm(W){\times}4.8cm(H)$. Specimens were fired from 1,400 to $1,700^{\circ}C$ at $50^{\circ}C$ intervals and held for 1hour at highest temperature. Apparent porosity, water absorption, firing shrinkage, bulk density, bend strength, whiteness were tested. Microstructures were observed by SEM. Results: When fired above $1450^{\circ}C$, all specimens showed 0% apparent porosity and water absorption, 20% firing shrinkage, and $6.1g/cm^3$ bulk density regardless of firing temperatures. SEM photomicrographs showed grain growth of zirconia occurred above $1,600^{\circ}C$. Whiteness was also largely changed above this temperature. Maximum bend strength of 1,05MPa was obtained at $1,550^{\circ}C$. Bend strength lowered slightly above this temperature and showed $950{\ss}\acute{A}$ at $1,700^{\circ}C$. Conclusion: In order to fit the colortone of zirconia artificial teeth, arbitrary choice of firing temperature higher than $1,500^{\circ}C$, up to $1,700^{\circ}C$ did not influence the mechanical strength.

하드터닝에서 CBN 공구홀더의 열변형이 가공정밀도에 미치는 영향 (Analysis of Thermal Displacement of PCBN Tool Holder for Machining Accuracy in Hard Turning)

  • 노승국;이찬홍;하재용
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2003년도 춘계학술대회 논문집
    • /
    • pp.363-366
    • /
    • 2003
  • The hard turning is a turning operation performed in high strength alloy steels (HRC>30) in order to reach surface roughness close to those obtained in grinding. This is possible because of availability of improved tool materials (polycrystalline cubic boron nitride. PCBN), ad more rigid machine tools. According to many previous work of hard turning mechanism, the maximum temperature of cutting can be raised up to 100$0^{\circ}C$. As the heat generation rate is very high, the thermal displacement of tool holder cannot be negligible. Therefore, the aim of this paper is to analyze effects of high heat generation at CBN tool tip to the thermal displacement of a tool holder in hard turning and finally geometric accuracy. The thermal behavior of a CBN tool holder is investigated by numerical simulation and experiment, and the result shows thermal elongation of microns order is possible during hard turning process.

  • PDF

우리나라 콩의 조리 성질 (Cooking Properties of Some Korean Soybeans)

  • 김성곤;김종군
    • 한국식품과학회지
    • /
    • 제20권5호
    • /
    • pp.699-703
    • /
    • 1988
  • 우리나라 콩중 장려품종(봉의)과 재래종(KW-12와 KLS-77005-1)을 $106^{\circ}C{\sim}121^{\circ}C$의 가압조건에서 조리하면서 최대 전단력을 측정하고 이로부터 조리속도를 분석 비교하였다. 시료콩 모두 $106^{\circ}C$에서는 150분, $121^{\circ}C$에서는 14분 후에 조리가 완료 되었으며 조리속도 상수는 서로 비슷하였다. 일정한 조리도를 나타내는 온도-시간과의 관계로부터 구한 Z-값은 봉의와 KLS-77005-1가 $11.5^{\circ}C$, KW-12가 $13.1^{\circ}C$ 이었다.

  • PDF

잎갈나무조림지의 벌목지와 비벌목지의 토양호흡에 관한 연구 (A Study on the Soil Respiration in Cutting and Uncutting Areas of Larix leptolepis Plantation)

  • 이규진;문형태
    • 생명과학회지
    • /
    • 제20권9호
    • /
    • pp.1353-1357
    • /
    • 2010
  • 공주 근교의 일본잎갈나무 조림지에서 벌목이 이루어지지 않은 비벌목지를 대조구, 벌목이 이루어진 벌목지를 처리구로 설정하여 토양호흡과 호흡에 영향을 주는 토양온도, 토양수분을 2008년 5월부터 12월까지 2주 간격으로 측정하였다. 조사기간 동안 대조구와 처리구의 평균 토양온도는 각각 $23.3{\pm}0.5^{\circ}C$, $25.9{\pm}3.1^{\circ}C$으로 처리구에서 높았으며, 토양수분은 각각 $27.76{\pm}7.12%$, $24.55{\pm}5.12%$으로 처리구에서 낮게 나타났다. 토양호흡량은 봄부터 하절기로 이행함에 따라 증가한 후 동절기에 이르기까지 감소하는 경향을 보였으며, 토양호흡과 토양온도와는 높은 상관관계($R^2$=0.8747)가 있었으나, 토양수분과는 유의성이 높지 않았다($R^2$=0.4437). 토양호흡량은 대조구와 처리구에서 모두 8월에 가장 높았으며, 이때 대조구와 처리구의 평균 토양호흡량은 각각 $0.82{\pm}0.13$, $1.32{\pm}0.10$ $CO_2g{\cdot}m^{-2}{\cdot}hr^{-1}$으로 나타났다. 대조구와 처리구에서 5월부터 12월까지 측정된 전체 호흡량은 각각 2,419.2, 3,610.8 $CO_2g{\cdot}m^{-2}$으로 대조구에 비해 처리구에서 49.3% 높은 것으로 나타났다. 본 연구의 결과 인위적인 삼림의 벌목은 토양 호흡량을 증가시켜 대기 중의 이산화탄소를 증가시킬 것으로 판단된다.

제주한란의 자생환경 특성 및 분포에 관한 연구 (Habitat Characteristics and Distribution of Cymbidium kanran Native to Jejudo, Korea)

  • 이종석
    • 한국환경복원기술학회지
    • /
    • 제7권1호
    • /
    • pp.40-49
    • /
    • 2004
  • This work carried out to define the characteristic of Cymbidium kanran habitat at Mt. Halla in Jejudo, Korea from the ecological point of view including geological and topographical features, air and soil temperature, relative humidity, fluctuations of light intensity, habitat vegetation, distribution altitude, area limit, and etc. And another goal of this study consider the conservation counterplan of the cymbidium habitat. Natural distribution areas of the cymbidium were observed more abundantly on the well drained south and east-facing slopes. Soil acidity was ranged from pH 4.1 to 5.3, and electric conductivity was ranged from 176.4 to 299.9 us/cm (average 215.3 us/cm). Base-saturation percentage of the habitat soil was below 50%, bulk density 0.42g/$cm^2$, particle density 2.05g/$cm^2$, humus content 26%, total nitrogen 0.82%, available phosphate 4.2 mg/kg, exchangeable potassium 0.63 Cmol/kg, calcium 0.44 Cmol/kg and magnesium 0.67 Cmol/kg. Annual mean air temperature was $15.4^{\circ}C$, however, air temperature was ranged $11.7{\sim}18.2^{\circ}C$ in spring, $21.2{\sim}23.8^{\circ}C$ in summer, $12.8{\sim}22.0^{\circ}C$ in fall and $5.5{\sim}7.8^{\circ}C$ in winter season. Annual mean soil temperature at depth of 10cm was $13.2^{\circ}C$ And minimum value was recorded $4.7^{\circ}C$ on January, and maximum value $22.5^{\circ}C$ on August. Relative humidity was ranged 90.8~94.7% in summer, 80.8~91.5% in fall and 77.6~84.2% in winter season. Minimum value was 56.5% on December, and maximum value was 100% on July and August. Light intensities were ranged from 400 to 1,800 lux at the greater part of Cymbidium kanran sites in Jejudo. Summer regarded as an lower light intensities was recorded to be range of 500~600 lux; however, autumn and winter were shown higher light regimes ranged from 3,500 to 3,800 lux. Therefore, one must be suprised that the cymbidium grow at the light condition of 6 lux (minimum) or 10,000 lux (maximum). Tree species keeping higher frequency rate and density were Eurya japonica, Camellia japonica, Castanopsis cuspidata, Carpinus laxiflora and Pinus densiflora. Number of trees growing in a 5${\times}$5m quardrat was 35 as an average, and proportion of evergreen versus deciduous was 5:1. Distribution altitude of the orchid habitat was ranged from 120m (low) to 840m (high) from sea level on the south facing slope of Mt. Halla, and was ranged eastern borderline of Gujwaup, Bukjejugun to western boundaries of Jungmundong, Seogwipo city. For the stable conservation of Cymbidium kanran habitat, sunlight regimes must be increased more by means of cutting trees or twigs in the site.

초고경도 Ti-Al-Si-N 나노복합체 코팅막의 미세구조 및 트라이볼로지 거동에 관한 연구 (A Study on Microstructure and Tribological Behavior of Superhard Ti-Al-Si-N Nanocomposite Coatings)

  • 허성보;김왕렬
    • 한국표면공학회지
    • /
    • 제54권5호
    • /
    • pp.230-237
    • /
    • 2021
  • In this study, the influence of silicon contents on the microstructure, mechanical and tribological properties of Ti-Al-Si-N coatings were systematically investigated for application of cutting tools. The composition of the Ti-Al-Si-N coatings were controlled by different combinations of TiAl2 and Ti4Si composite target powers using an arc ion plating technique in a reactive gas mixture of high purity Ar and N2 during depositions. Ti-Al-Si-N films were nanocomposite consisting of nanosized (Ti,Al,Si)N crystallites embedded in an amorphous Si3N4/SiO2 matrix. The instrumental analyses revealed that the synthesized Ti-Al-Si-N film with Si content of 5.63 at.% was a nanocomposites consisting of nano-sized crystallites (5-7 nm in dia.) and a three dimensional thin layer of amorphous Si3N4 phase. The hardness of the Ti-Al-Si-N coatings also exhibited the maximum hardness value of about 47 GPa at a silicon content of ~5.63 at.% due to the microstructural change to a nanocomposite as well as the solid-solution hardening. The coating has a low friction coefficient of 0.55 at room temperature against an Inconel alloy ball. These excellent mechanical and tribological properties of the Ti-Al-Si-N coatings could help to improve the performance of machining and cutting tool applications.

감압증류장치를 이용한 Oilsands Bitumen의 물리화학적 특성 연구 (Physical and Chemical Characteristics of Oilsands Bitumen Using Vacuum Distillation)

  • 김경훈;전상구;노남선;김광호;신대현;박효남;한명완
    • 에너지공학
    • /
    • 제17권1호
    • /
    • pp.15-22
    • /
    • 2008
  • 본 연구는 감압증류장치(Vacuum Distillation Unit)를 이용하여 캐나다산 아사바스카 오일샌드 역청 (Athabasca Oilsands Bitumen)의 증류액(Distillates)및 잔사유(Residue)에 대한 물리화학적 특성변화를 살펴보기 위하여 수행되었다. 감압증류장치를 이용하여 생성된 증류액 및 잔사유의 원소분석, SARA 분석, 비점분포 분석, 분자량 측정, API 비중 등을 측정하였으며, 감압증류실험장치는 6 l 용량의 Vessel, 충진컬럼, 응축기, 리플럭스, 증류액 포집플라스크, 온도제어장치 등으로 구성되었다. 증류액의 구분 조건은 최대 감압 및 최대 $320^{\circ}C$의 승온조건 하에 총 4단계로 수행되었다. 분석 결과 오일샌드 역청에 비해 증류액의 황분 및 평균분자량은 현저히 감소하였다. 증류액의 온도가 고온으로 갈수록 증류액의 수소함량은 감소하고, 황 함량 및 평균분자량은 증가하는 경향을 보였다.