Low temperature full-thickness burn developed after the suction blister epidermal graft

( Ro Woo Lee ),( Han Mi Jung ),( Soo Hyung Kim ),( Sung Hye Eun ),( Hyun Jeong Ju ),( Ji Hae Lee ),( Jung Min Bae ),( Gyong Moon Kim ) 대한피부과학회 2019 대한피부과학회 학술발표대회집 Vol.71 No.1

Suction blister epidermal graft (SBEG) is used for treating vitiligo refractory to conventional treatment including phototherapy. It is done by transplanting blisters from donor site to recipient site. Usually the negative pressure is given to the donor site to form blisters, and heat is applied to reduce the time. Its complications include infection, post-inflammatory hyperpigmentation and scarring. A 23-year-old woman presented with a vitiligo lesion which remained stable despite 1 year of phototherapy. For that lesion, we conducted SBEG. In the process, we applied a infrared heater to accelerate blister formation on the donor site. The heater was placed 70 cm away from the site and kept on for 40 minutes. While applying heat, the patient felt no discomfort except for a little warmth. There was no complication on the donor site immediately after the surgery, but slight oozing, crusts, and granulation tissues were observed a week later. We found there was a full thickness burn on the donor site and diagnosed it as low temperature burn. Recovery for the injury was observed after intensive burn care. A relationship between the temperature and the duration of heat exposure has long been known. At the temperature as low as 44℃, superficial burn can occur in more than 6 hours. As the temperature increases, the time for burn decreases. Like our case, low temperature burn can occur in healthy people without causing pain or heating sensation.

Characteristics of Resistant Lines to High-Temperature Injury in Ginseng (Panax ginseng C. A. Meyer)

Lee, Joon-Soo,Lee, Jang-Ho,Ahn, In-Ok The Korean Society of Ginseng 2010 Journal of Ginseng Research Vol.34 No.4

This experiment was conducted to examine ginseng lines resistant and susceptible to high-temperature injury and to investigate characteristics of the selected lines: leaf burning phenomenon, chlorophyll content, quantum yield, and maximum light interception rate. The leaf burning phenomenon incidence rates of the resistant lines Yunpoong, high-temperature injury resistance (HTIR)1, HTIR2, and HTIR3 were low: 5.8%, 3.6%, 4.0%, and 1.9%, respectively. Resistance of the susceptible lines Chunpoong, high-temperature injury susceptible (HTIS)1, and HTIS2 was high: 58.5%, 23.2%, and 21.7%, respectively. The chlorophyll content (SPAD value) of the resistant lines Yunpoong, HTIR1, HTIR2, and HTIR3, which were exposed to high temperatures and intense light, remained as high at 24.8, 27.9, 24.9, and 30.6, respectively, but that of the susceptible lines Chunpoong, HTIS1, and HTIS2 was low at 21.0, 21.1, and 20.1, respectively. During the summer season, the quantum yield of the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) changed little, but that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) changed dramatically. The maximum light interception rate (Fm/Fv value) for the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) was as high as 0.848, 0.794, 0.805, and 0.813, respectively, while that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) was 0.678, 0.642, and 0.717, respectively. Based on these results, the high-temperature injury-resistant lines seemed to be less susceptible to high light, even at high temperatures. Future studies on red ginseng quality and its active ingredients in resistant ginseng lines and field experimentation will be conducted to verify the potential of the resistant lines.

A comparative study of the ignition and burning characteristics of afterburning aluminum and magnesium particles

임지환,이상협,윤웅섭 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

Ignition and the burning of air-born single aluminum and magnesium particles are experimentally investigated. Particles of 30 to 106 μm-diameters were electrodynamically levitated, ignited, and burnt in atmospheric air. The particle combustion evolution was recorded by high-speed cinematography. Instant temperature and thermal radiation intensity were measured using two-wavelength pyrometry and photomultiplier tube methods. Ignition of the magnesium particle is prompt and substantially advances the aluminum particle by 10 ms. Burning time of the aluminum particles is extended 3 to 5 times longer than the magnesium particles. Exponents of a power-law fit of the burning rates are 1.55 and 1.24 for aluminum and magnesium particles, respectively. Flame temperature is slightly lower than the oxide melting temperature. For the aluminum, dimensionless flame diameter is inert to the initial particle size, but for the magnesium inversely proportional to the initial diameter.

Characteristics of Resistant Lines to High-Temperature Injury in Ginseng(Panax ginseng C. A. Meyer)

Joon-Soo Lee,Jang-Ho Lee,In-Ok Ahn 고려인삼학회 2010 Journal of Ginseng Research Vol.34 No.4

This experiment was conducted to examine ginseng lines resistant and susceptible to high-temperature injury and to investigate characteristics of the selected lines: leaf burning phenomenon, chlorophyll content, quantum yield, and maximum light interception rate. The leaf burning phenomenon incidence rates of the resistant lines Yunpoong, high-temperature injury resistance (HTIR)1, HTIR2, and HTIR3 were low: 5.8%, 3.6%, 4.0%, and 1.9%, respectively. Resistance of the susceptible lines Chunpoong, high-temperature injury susceptible (HTIS)1, and HTIS2 was high: 58.5%, 23.2%, and 21.7%, respectively. The chlorophyll content (SPAD value) of the resistant lines Yunpoong, HTIR1, HTIR2, and HTIR3, which were exposed to high temperatures and intense light, remained as high at 24.8, 27.9, 24.9, and 30.6, respectively, but that of the susceptible lines Chunpoong, HTIS1, and HTIS2 was low at 21.0, 21.1, and 20.1, respectively. During the summer season, the quantum yield of the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) changed little, but that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) changed dramatically. The maximum light interception rate (Fm/Fv value) for the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) was as high as 0.848, 0.794, 0.805, and 0.813, respectively, while that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) was 0.678, 0.642, and 0.717, respectively. Based on these results, the hightemperature injury-resistant lines seemed to be less susceptible to high light, even at high temperatures. Future studies on red ginseng quality and its active ingredients in resistant ginseng lines and field experimentation will be conducted to verify the potential of the resistant lines.

동축류 제트에서 초기 온도 변화에 따른 층류 부상화염

김길남(Kil Nam Kim),원상희(Sang Hee Won),정석호(Suk Ho Chung) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

Characteristics of laminar lifted flames for highly diluted propane with nitrogen have been investigated in various initial temperatures, especially in high temperature. Liftoff height and liftoff velocity are investigated for various fuel mole fraction and initial temperature. The liftoff height decreases as fuel mole fraction and initial temperature increase, and it can be correlated well with laminar burning velocity although the increasing slope of liftoff height is differ from initial temperature and fuel mole fraction. These results show that lifted flames are stabilized based on the balance mechanism regardless of its initial temperature up to 900K. Liftoff phenomenon can be observed for smaller jet velocity than laminar burning velocity in ambient temperature, and it can be attributed to the effect of buoyancy. When the effect of buoyancy diminishes, Ri < 0.1, non-dimensional liftoff velocity, (ReRi)?¹ is correlated well with stoichiometric laminar burning velocity.

Relaxation and Phase-transition Characteristics of Relaxor Ferroelectric Potassium Lithium Niobate

전병옥,정중현,최병춘,황윤화 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.11

The electric modulus relaxations were considered to be coupled phenomena between the polarization fluctuations < P2 > due to local symmetry breaking and ionic hopping through nearest neighbor sites. The Nb-rich potassium lithium niobate (K5.595Li3.125Nb11.28O30) crystals exhibited a ferroelectric diffused phase transition around the dielectric maximum temperature Tmax = 350 C. The electric modulus relaxations were characterized by using the Cole-Davidson distribution of the electric modulus relaxation times at frequencies ranging from 100 Hz to 1 MHz. Although the lattice constants along the a-axes and the c-axes and the tetragonal unit cell volume showed linear expansions with increasing temperature T, the axial ratio c/a decreased with increasing T at temperatures below the Burn’s temperature TB = 550 C. The dielectric relaxation accompanied the high ionic conduction in the temperature range above Tmax = 350 C. The ac conductivity 0(!) was analyzed by using the formulae 0(!)/dc = 1 + (!/!O)n, where !O is the crossover frequency. It was considered that a double-Arrhenius behavior of the dc conductivity dc at temperatures around the Burn’s temperature TB = 550 C was suspected of thermally activated motions in the random distribution of oxygen vacancies and lithium ions. The ac universality could result in a disordered configuration of the mobile ions, i.e., the dc conductivity at temperatures above TB. The slow relaxations of the nano-sized polar regions may contribute to the dc conductivity dc at temperatures below TB. The characteristic relaxation time CD showed a change in activation energy from 1.08 eV to 0.80 eV at temperatures around TB. The scaling factor " ·T/"0 1 increased in proportion to (TB − T) at T < TB, but was almost constant at T > TB, where "0 1 is the high frequency dielectric constant and T is the temperature in Kelvin.

Analysis of heat diffusion considering driving images on 6-inch flexible AMOLED display

Jeon Chang Hoon,Park Ji Woong,Kang Byung Wook,Jang Su Hyuk,Kwon Kyung Joon,Hong Soon Kwang,Ha Yong Min,Jang Jin 한국정보디스플레이학회 2023 Journal of information display Vol.24 No.3

We report the heat diffusion on flexible active-matrix organic light-emitting diode (AMOLED) displays. Two-dimensional heat diffusion is used for the heat conduction and convection analysis, generated on the surface of a flexible AMOLED display. The heat diffusion parameters and the time constant are studied in terms of the driving conditions of a 6-inch flexible AMOLED display. The temperature distribution on the screen is obtained by applying heat diffusion using the finite difference method (FDM) with an FPGA driving board. We can predict temperature more precisely by calculating temperature changes according to the images. The proposed method improves the accuracy of predicting the temperature. The average and standard deviation of the temperature error (TER) are ∼0.5°C and ∼0.5°C for the proposed method, respectively. For the conventional method, the values are ∼4.5°C and ∼0.7°C, respectively, neglecting the increase in temperature based on the images. This method can be used in compensation technology for OLEDs and thin film transistors (TFTs) that require accurate temperature distribution on the screen.

예연소기 개발관련 금속발화 사례연구

문인상(Moon, Insang),문일윤(Moon, Ilyoon),하성업(Ha, Seun-Up) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.5

예연소기의 특성상 연소가 이루어지는 지역은 2600 K이상의 고온이므로 연소구간 후단에 희석구간 혹은 2차 연소구간을 마련하고 여기서 여분의 산소를 혼합하여 전제적인 평균온도를 낮춘다. 그러므로 여분의 산소와 1차 연소구간에서 발생한 연소가스가 잘 섞이지 않는다면 국부적으로 높은 온도 가스가 존재할 것이다. 그리고 이 가스들이 금속과 반응한다면 순간적으로 2차 반응을 이끌어 내어 큰 사고로 이어질 수 있다. 또한 예연소기 개발에 사용되는 각종 센서는 연소가스와 직접 접촉하며 보호대책이 마련하는 것이 매우 어렵기 때문에 설계점과 센서의 특성 등을 고려하여 매우 신중하게 위치와 종류를 선정해야한다. 그럼에도 불구하고 실제로 예연소기 시험 중 센서에서 점화가 일어나 노즐와 배관을 손상시킨 사건이 발생하였으며 향후 이러한 사고를 방지하기 위한 설계변경이 이루어 졌다. The second reaction zone was prepared for mixing between exhaust gas from the first reaction zone and additional oxygen to reduce the final temperature. Therefore it is very important for the two gas to be mixed completely or locally high temperature zone must exist. If this high temperature gas react with metal, it can instantly lead to a big accident. Moreover, all the sensors used for preburner development contact the exhaust gas out of the preburner directly. In addtion, it is very difficult to prepare for a protection from the high temperature oxygen gas. Therefore, the sensors themselves and locations should be carefully decided. However, even though all the efforts, an accident occurred because of an ignition of a thermocouple. Accordingly, design changes were adapted to prevent from the same incident.

Feasibility study of ultra-low NOx Gas turbine combustor using the RML combustion concept

Tien Giap Van,Jeong Jae Hwang,Min Kuk Kim,안국영 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

A new combustion concept, the so called RML, was investigated to validate its application as a gas turbine combustor for combustor outlet temperatures over 1973 K. The feasibility study of the RML combustor was conducted with zero dimensional combustion calculations. The emission characteristics of RQL, LEAN, EGR and RML combustors were compared. The calculation results showed that the RQL combustor has lower NOx emissions than the LEAN at high outlet temperature. NOx emissions of the RML combustor at equivalence ratio of the rich chamber of 2.0 can be reduced by 30 % compared with the EGR combustor, and lower than the RQL combustor at a combustor outlet temperature over 1973 K. However, the CO emissions of the RML combustor were higher than those of the LEAN and EGR combustors. Also, the possibility of applying the RML combustor to gas turbines was discussed considering residence time, equivalence ratio of the rich chamber and recirculation rate. Although further research to design and realize the proposed RML combustor is needed, this study verified that the RML concept can be successfully used in a gas turbine combustor.

A Study on the Performance of an LPG(Liquefied Petroleum Gas) Engins Converted from a Compression Ignition Engine

최경호,김태권,조영래,정연종,Jerald Caton,한성빈 한국에너지학회 2007 에너지공학 Vol.16 No.1

- The purpose of this study was to investigate the reduction of exhaust gas temperature in a LPG engine that had been converted from a diesel engine. A conventional diesel engine was modified to a LPG (Liquefied Petroleum Gas) engine by replacing the diesel fuel injection pump with a LPG fuel system. The research was performed by measuring the exhaust gas temperature upon varying spark ignition timing, air-fuel ratio, compression ratio, and different compositions of butane and propane. Engine power and exhaust temperature were not influenced by various butane/propane fuel compositions. Finally, among the parameters studied in this investigation, spark ignition timing is one of the most important in reducing exhaust gas temperature.