• Title/Summary/Keyword: Cold and Heat

Search Result 1,974, Processing Time 0.032 seconds

A Study on Tensile Restraint Crack Critical Stress Characteristcs of Gravity-Wet-Type Underwater Welded Joints (중력식 습식 수중용접부의 인강구속균열 임계응력 특성에 관한 연구)

  • O, Se-Gyu;Gang, Mun-Ho;Han, Sang-Deok
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.61-65
    • /
    • 1987
  • In this study, the characteristics of TRC (tensile restraint crack) critical stress in the gravity type underwater wet welding process and in the in-air welding have been investigated for Y, y and 45$^{\circ}$r grooves using the KR Grade A-3 steel plates and the E4303 covered electrodes. The following results were obtained: (1) In the TRC tests, the initial critical stress of Y groove is higher than those of the 45$^{\circ}$r single bebel grooves in both in-air and underwater weldings, and the cold fracture sensitivity is higher in the underwater welding than in the in-air welding. (2) The hardness of underwater weld metal is the highest in heat affected zone is about Hk 365 in the in-air weld but Hk 670 in the underwater weld which is higher for cooling speed is more rapid, resulting in the lower critical stress by increase of fracture sensitivity. (3) The diffusible hydrogen quantity for 48 hours is about 18cc/100g-weld-metal in the in-air welding but 48cc/100g-weld-metal in the underwater welding. So that, in the case of underwater welding the diffusible hydrogen penetrates about 3 times more than that in the in-air welding.

  • PDF

A Study on Tensile Restraint Crack Critical Stress Characteristcs of Gravity-Wet-Type Underwater Welded Joints (중력식 습식 수중용접부의 인강구속균열 임계응력 특성에 관한 연구)

  • Sae Kyoo Oh;Moon Ho Kang;Sang Deok Han
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.23 no.2
    • /
    • pp.15-15
    • /
    • 1987
  • In this study, the characteristics of TRC (tensile restraint crack) critical stress in the gravity type underwater wet welding process and in the in-air welding have been investigated for Y, y and 45°r grooves using the KR Grade A-3 steel plates and the E4303 covered electrodes. The following results were obtained: (1) In the TRC tests, the initial critical stress of Y groove is higher than those of the 45°r single bebel grooves in both in-air and underwater weldings, and the cold fracture sensitivity is higher in the underwater welding than in the in-air welding. (2) The hardness of underwater weld metal is the highest in heat affected zone is about Hk 365 in the in-air weld but Hk 670 in the underwater weld which is higher for cooling speed is more rapid, resulting in the lower critical stress by increase of fracture sensitivity. (3) The diffusible hydrogen quantity for 48 hours is about 18cc/100g-weld-metal in the in-air welding but 48cc/100g-weld-metal in the underwater welding. So that, in the case of underwater welding the diffusible hydrogen penetrates about 3 times more than that in the in-air welding.

An Improvement in the Properties of MH Electrode of Ni/MH Battery by the Copper Coating (Ni/MH 전지에서 Cu 도금에 의한 음극활물질의 전극 특성 향상)

  • Cho, Jin Hun;Kim, In Jung;Lee, Yun Sung;Nahm, Kee Suk;Kim, Ki Ju;Lee, Hong Ki
    • Applied Chemistry for Engineering
    • /
    • v.8 no.4
    • /
    • pp.568-574
    • /
    • 1997
  • The effect of microencapsulation of maetal hydride (MH) with copper on the electrode performance of a Ni/MH battery has been investigated. The MH electrodes were prepared with a combination of cold press and paste methods. The discharge capacity of the electrode increased with an addition of small amounts if CMC into the electrode, but decreased when heat-treated in an oxygen-free nitrogen flow. The capacity of a Cu-coated $LaNi_5$ electrode was higher than that of LaNi5electrode. The discharge capacity of the electrode prepared with Cu-coated $LaNi_5$ increased with the increase of copper content in the electrode. It is considered that the increase of copper content enhanced the current density on the electrode surface, leading to the increase of the discharge capacity The MH electrode coated by an acidic electroless plating method showed much higher discharge capacity than that using an alkaline electroless plating method. The discharge capacity of the $LaNi_{4.5}Al_{0.5}$ electrode was higher than that of the $LaNi_5$ electrode. Also, the effect of microencapsulation on the deactivation of $LaNi_5$ was studied using an absorption-desorption cycle in CO-containing hydrogen.

  • PDF

The Literature Study on Classification of Cause and the Effect of Acupuncture and Moxibustion Treatment for Dentalgia (치통(齒痛)의 병인병기(病因病機) 및 침구치료(鍼灸治療)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Lee, Seong-no;Lee, Hyun;Lee, Byung-ryul
    • Journal of Haehwa Medicine
    • /
    • v.10 no.1
    • /
    • pp.269-286
    • /
    • 2001
  • Objectives : This Investigation was aimed to find out the Classification of Cause and the Effect of Acupuncture and Moxibustion Treatment for Dentalgia Methods : We surveyed the oriental medical books from $\ll$HungTiNeiChing$\gg$ to recent published books concerning the Acupuncture therapy for Dentalgia Results : 1. Since the time of $\ll$HungTiNeiChing$\gg$ there was called "yateng", "yatong", "chiyaqutong", "kouchitong", "nichi", "chichong", "fengchi", "chongshitong", "chongshiyachi", "chifengzhongtong", "chiyinzhong", "yachuangzhongtong" 2. The Oriental Medical cause of Dentalgia are fire, wind, cold, blood stasis, stomach-heat, phlegm, difficiency of kidney, late snack, insect and wound, and then the Western Medical cause are cacodontia, periodontal disease, trigeminal nerve pain, stress 3. The meridians used for the treatment are large intestine, stomach, triple warmer, gallbladder and small intestine 4. The most frequently used acupuncture point for the treatment are Hapkok(LI3), Naejong(S44), Hyopko(S6), Igan(LI2), Sohae(H3), Yanggok(SI5), Hagan(S7), Taeyong(S5), Samgan(LI3), Kokehi(LI11) 5. The most frequently used moxibustion for the treatment are Sungjang(CV24), Yolgyol(L7), Kyonu(LI15), Taeyon(L9), Hapkok(LI3) 6. In the superior dental pain there commonly used the acupuncture point of stomach meridian, triple warmer meridian, gallbladder meridian in the inferior dental pain there commonly used the acupuncture point of large intestine meridian. 7. The most frequently used acupuncture point for the superior dental pain are Naejong(ST44), Yanggok(SI5), Chongnyong(G17), Kakson(TE20), In the inferior detal pain there are Taeyong(S5), Hapkok(LI3), Igan(LI2), Sangyang(LI1), Samgan(LI3) 8. In the treatment of dental pain The Acupuncture therapy utilized the division of region are the Erzhen therapy(耳針療法), the Touzhen therapy(頭鍼療法), the Shouzhen therapy(手鍼療法), the Zuzhen therapy(足鍼療法), the Bizhen therapy(鼻針療法), the Wanhuaizhen therapy 9. In dental pain the other therapy are the Taozhen therapy(陶鍼療法), the Pifuzhen therapy(皮膚針療法), the Dianzhen therapy(電鍼療法), the Yaozhen therapy(藥針療法).

  • PDF

Identification of the Protein Function and Comparison of the Protein Expression Patterns of Wheat Addition Lines with Wild Rye Chromosomes (야생 호밀 염색체 첨가 밀 계통의 단백질 발현 양상 비교 분석)

  • Lee, Dae Han;Cho, Kun;Woo, Sun Hee;Cho, Seong-Woo
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.64 no.4
    • /
    • pp.373-383
    • /
    • 2019
  • The objectives of this study were to compare the protein expression patterns and degrees and identify the protein function of disomic addition lines (DAs) in Leymus racemosus, in order to improve the quality of wheat. Upon SDS-PAGE, L. racemosus showed two major protein bands whereas Chinese Spring (CS) had four major protein bands of high molecular weight. The DA(s) generally showed a similar protein expression pattern to that of CS, because 42 chromosomes were from CS and two chromosomes were from L. racemosus. However, only the L.r[J] line showed two protein bands of between 15 and 20 kDa, like L. racemosus. Image analysis based on 2-DE revealed that L.r[F] had the most upregulated protein spots, whereas L.r[N] had the least upregulated protein spots. For L.r[I], the frequency of the downregulated protein spots was higher than that of the upregulated ones. Using MALDI-TOF MS, the protein function was identified for each protein spot on the 2-DE polyacrylamide gel. The protein spots were classified into 11 groups according to protein function. Among the 11 groups, most protein spots of the DA(s) were identified as proteins related to metabolism. Additionally, unique protein spots of the DA(s) were related to abiotic stressors such as cold and heat. Those proteins are useful for improving wheat quality with resistance against abiotic stressors.

A Study on Standardization of Test Method for Water Vapour Permeability of Textiles Fabrics (군용 피복류의 투습도 시험방법 표준화 연구)

  • Lee, Min-Hee;Hong, Seong-Don;Chung, Il-Han
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.10
    • /
    • pp.27-33
    • /
    • 2016
  • Military textiles with breathable waterproof materials are expanding as form of winter clothes. Waterproof moisture-permeable clothes are very important for soldiers to survive in cold weather operations because they prevent loss of body heat from the penetration of water into the human body. Korea military uses the water resistance and moisture permeability to test the performance of waterproof moisture-permeable materials. Moisture permeability is measured according to the amount of evaporated water vapor passing through a fabric under specified temperature and humidity by using acetic acid potassium presented in KS K 0594. However, the test procedure for measuring the moisture permeability in the standard is presented only briefly and the preparation procedures for the test in accredited testing institutions are applied differently, leading to significant deviation of the results. This paper compares the procedures of testing institutions and examines the factors that affect moisture permeability. Finally, we propose a procedure to reduce the deviation of results and apply the proposed procedure in testing institutions. Our analysis results with one-way ANOVA under significant level (0.05) confirm that the deviation of results is reduced.

Intraspecific Androgenesis in Mud Loach (Misgurnus mizolepis): II. Diploid Restoration and Viability Assessment (미꾸라지(Misgurnus mizolepis)의 웅성발생성 처녀생식: II. 웅성발생성 이배체 유도 및 생존능력 평가)

  • Nam, Yoon-Kwon;Bang, In-Chul;Noh, Choong-Hwan;Cho, Young-Sun;Kim, Dong-Soo
    • Journal of Aquaculture
    • /
    • v.19 no.4
    • /
    • pp.281-287
    • /
    • 2006
  • Intraspecific diploid androgenesis was achieved in mud loach (Misgurnus mizolepis) by the inhibition of the first mitotic division using combined thermal treatment. A combined thermal treatment (heat shock at $40.5\;^{\circ}C$ for 120 sec followed by cold treatment at $1\;^{\circ}C$ for 45 min) applied to the 1st metaphase of cell division (28 min post insemination at $25\;^{\circ}C$) successfully recovered viable androgenetic diploidy. Mean hatching success of the androgenetic diploid group was 29.6%, and the average yield out of total eggs taken was about 7% assessed at 1 week of age. However, relatively large variations in the yield of diploid androgenesis were observed among different egg batches used as cytoplasmic donors. Successful diploidization was confirmed by flow cytometric analysis, and parthenogenic reproduction in a paternal exclusive manner was verified with transgene dosage. Significant mortality was found in most androgenetic groups especially from hatch to 1 month of age, although such mortality was stabilized later.

Effects of Welding Processes on the Low Temperature Impact Toughness of Structural Steel Welded Joints (용접방법에 따른 구조용강 용접 접합부의 저온 충격인성 특성)

  • Lee, Chin Hyung;Shin, Hyun Seop;Park, Ki Tae
    • Journal of Korean Society of Steel Construction
    • /
    • v.24 no.6
    • /
    • pp.693-700
    • /
    • 2012
  • In this study, the Charpy impact test along with metallurgical observation was conducted to evaluate low temperature impact toughness of structural steel welds with different welding processes to find out the optimal welding process to guarantee the required impact toughness at low temperatures. The welding processes employed are shield metal arc welding (SMAW) and flux cored arc welding(FCAW), which are commonly used welding methods in construction. The Charpy impact test is a commercial quality control test for steels and other alloys used in the construction of metallic structures. The test allows the material properties for service conditions to be determined experimentally in a simple manner with a very low cost. To investigate the impact toughness at low temperatures of the steel welds, specimens were extracted from the weld metal and the heat affected zone. Standard V-notch Charpy specimens were prepared and tested under dynamic loading condition. The low temperature impact performance was evaluated based on the correlation between the absorbed energy and the microstructure. Analysis of the results showed that the optimal welding process to ensure the higher low temperature impact toughness of the HAZ and the weld metal is SMAW process using the welding consumable for steels targeted to low temperature use.

Uncooled Metallic Thin-film Thermopile Infrared Detector (비냉각 금속 박막형 열전퇴 적외선 검지기)

  • Oh, Kwang-Sik;Cho, Hyun-Duk;Kim, Jin-Sup;Lee, Yong-Hyun;Lee, Jong-Hyun;Lee, Jung-Hee;Park, Se-Il
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.37 no.2
    • /
    • pp.5-12
    • /
    • 2000
  • Uncooled metallic thin-film thermopile infrared detectors have been fabricated, and the figures of merit for the detectors were examined. The hot junctions of a thermopile were prepared on a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$-membrane which acts as a thermal isolation layer, the cold junctions on the membrane supported with the silicon rim which functions as a heat sink, and Au-black was used as an infrared absorber. Infrared absorbance of Au-black, which strongly depends on the chamber pressure during Au-evaporation and its mass per area, was found to be about 90 % in the wavelength range from 3${\mu}{\textrm}{m}$ to 14${\mu}{\textrm}{m}$. Voltage responsivity, noise equivalent power, and specific detectivity of Bi-Sb thermopile infrared detector at 5 Hz-chopping frequency were about 10.5V/W, 2.3 nW/Hz$^{1/2}$, 및 $1.9\times10^{7}$ cm.Hz$^{1/2}$/w at room temperature in air, respectively.

  • PDF

A Study on the Structural Performance of Hybrid Studs Subjected to Compression and Torsion (압축과 비틂을 동시에 받는 복합스터드의 구조적 성능에 관한 연구)

  • Jung, Yun Jin;Kwon, Young Bong;Kwak, Myong Keun;Bae, Kyu Woong
    • Journal of Korean Society of Steel Construction
    • /
    • v.18 no.5
    • /
    • pp.543-551
    • /
    • 2006
  • Cold-formed steel studs that are being used as load-bearing members of wall panels for steel houses have a problem with their insulation due to the heat bridging of their web. Some additional thermal insulating materials should be used. To solve this problem, the new-concept hybrid stud, which consists of a galvanized steel sheet (t = 1.0 m - 12.0 m) and a GFRP panel (t = 4.0-6.0 mm), has recently been developed. An investigation on the structural behavior and the strength capacity of this new hybrid stud has been conducted so that it can be used in load-bearing wall panels of residential buildings. This paper describes the axial compression-torsion test results of the hybrid studs under both axial compression and torsion using ATTM. The main factors of the test were the stud length, the magnitude of the initial compressive force, and the loading method of the monotonic or cyclic loading. The torsion was applied increasingly while the initial compression was kept constant to the failure of the hybrid section. The advanced analysis results obtained form the finite element procedure that considered the material properties of the high-strength galvanized steel and the GFRP were compared with the test results for verification.