• International Journal of Automotive Technology
• /
• v.6 no.5
• /
• pp.445-451
• /
• 2005

Most of the pollutants from passenger cars are emitted during the cold-transient phase of the FTP-75 test. In order to reduce the exhaust emissions during the cold-transient period, it is essential to warm up the catalyst as fast as possible after the engine starts, and the Unburned Exhaust Gas Ignition (UEGI) technology was developed through our previous studies to help close-coupled catalytic converters (CCC) reach the light-off temperature within a few seconds after cold-start. The UEGI system operates by igniting the unburned exhaust mixture by glow plugs installed upstream of the catalyst. The flame generates a high amount of heat, and if the heat is concentrated on a specific area of monolith surface, then thermal crack or failure of the monolith could occur. Therefore, it is very important to monitor the temperature distribution in the CCC during the UEGI operation, so the local temperatures in the monolith were measured using thermocouples. Experimental results showed that the temperature of CCC rises faster with the UEGI technology, and the CCC reaches the light-off temperature earlier than the baseline case. Under the conditions tested, the light-off time of the baseline case was 62 seconds, compared with 33 seconds for the UEGI case. The peak temperature is well under the thermal melting condition, and temperature distribution is not so severe as to consider thermal stress. It is noted that the UEGI technology is an effective method to warm up the catalyst with a small amount of thermal stress during the cold start period.

• Korean Journal of Metals and Materials
• /
• v.47 no.8
• /
• pp.482-487
• /
• 2009

In order to investigate the effects of intermediate heat treatment between cold rolling passes on the hardness and corrosion properties of a Zr alloy incorporating Nb (Zr-1.49Nb-0.38Sn-0.20Fe-0.11Cr) strip, three different intermediate heat treatment processes ($580^{\circ}C{\times}4hrs$, $600^{\circ}C{\times}2hrs$ and $620^{\circ}{\times}1hrs$) were designed based on a recrystallization map and an accumulated annealing parameter. Test samples from the different processes were investigated by a hardness test, corrosion test, and microstructure analysis and appropriate heat-treatment conditions were thereupon proposed. The sample subjected to an intermediate heat treatment of $580^{\circ}C{\times}4hrs$ was harder than that undergoing $600^{\circ}C{\times}2hrs$ and $620^{\circ}C{\times}1hr$ while the corrosion resistance of the sample that received an intermediate heat treatment of $580^{\circ}C{\times}4hrs$ was superior to that of the other specimens. Considering the trade-off of hardness and corrosion resistance, an intermediate heat treatment process of $600^{\circ}C{\times}2hrs$ is proposed to improve the manufacturing process of the alloy strip.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.59 no.6
• /
• pp.127-135
• /
• 2017

In this study, a cold well and a warm one with the distance of 100 m were installed in the alluvial aquifer. Groundwater used as the heat and the cold source of heat pump was designed to flow into the warm and the cold well with a diameter of 200 mm. In order to increase the heat and cold storage in aquifer, six auxiliary wells with the diameter of 50 mm and the depth of 30 m were installed at an interval of 5 m from the main well. Also, heat pump 50 RT, the thermal tank $40m^3$, and a remote control and monitoring system were installed in three single-span greenhouses ($2,100m^2$) for growing tomato in Buyeo, Chungcheongnam-do. According to the aquifer heat storage test which had been conducted from Aug. 31 to Sep. 22, 2016, warm water of $850m^3$ was found to flow into warm well. The temperature of the injected water was $30^{\circ}C$ (intake temperature : $15^{\circ}C$), and the heat of 12.8 Gcal was stored. The greenhouse heating test in winter had been conducted from Nov. 21, 2016 to Apr. 30, 2017. On Nov. 21, 2016 when heating greenhouse started, the aquifer temperature of the warm well was $18.5^{\circ}C$. The COP for heating with water source at $18.5^{\circ}C$ was 3.8. The intake water temperature of warm well was gradually lowered to the temperature of $15^{\circ}C$ on Jan. 2, 2017 and the heat pump COP was measured to be 3.2 at that time. As a result, the heat pump COP was improved by 18 %. and retrieval heat was 8 Gcal, the retrieval rate of heat stored in aquifer was estimated at 63 %.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.2
• /
• pp.190-195
• /
• 2004

The effect of heat treatment on torsion characteristics of high nitrogen steel wire has been studied by torsion test, tensile test, specific resistivity, X-ray diffraction and scanning electron microscopy. After heat treatment at 600∼$700^{\circ}C$, torsion cycle was increased with increasing temperature. Especially, in case of high nitrogen steel wire heat teated at $650^{\circ}C$, torsion cycle was sharply increased. It is estimated that cold worked high nitrogen steel wire started to recrystallize and phase transform at 64$0^{\circ}C$ in air atmosphere.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.27 no.8
• /
• pp.426-431
• /
• 2015

The advantages of a printed circuit heat exchanger (PCHE) are the compactness and efficiency derived from its heat-transfer characteristics; furthermore, a PCHE for which a diffusion bonding method was used during production can be applied to extreme environments such as a cryogenic condition. In this study, a micro-channel PCHE fabricated by diffusion bonding was investigated in a cryogenic environment regarding its thermal performance and the pressure drop. The test rig consists of an LN2 storage tank, vaporizers, heaters, and a cold box, whereby the vaporized cryogenic nitrogen flows in hot and cold streams. The overall heat-transfer coefficients were evaluated and compared with traditional correlations. Lastly, we suggested the modified heat-transfer correlations for a PCHE in a cryogenic condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.102-102
• /
• 2009

The piezoelectric transformer have attracted a lot of interest in recent years because of their potential applications in electronic devices. However, their reliability in practical applications has not been systematically studied. For many piezoelectric materials, the temperature reliability are among the biggest concerns. This paper presents an experimental study of the piezoelectric transformers with the focus on its reliability under varying temperature conditions.

• Journal of Sasang Constitutional Medicine
• /
• v.23 no.2
• /
• pp.240-253
• /
• 2011

1. Objectives: The purpose of this study was to survey the Original symptoms(素證) of Soyangin's and to compare the tendency of their symptoms between Soyangin Heat-related diarrhea accompanied by headache(身熱頭痛亡陰證) and Soyangin Cold-related diarrhea accompanied by abdominal pain(身寒腹痛亡陰證). 2. Methods: We recruited 56 Soyangin subjects in the Korean Medicine clinic and researched their original symptoms. Subjects were diagnosed by the Sasang Constitutional specialists and Sasang Constitutional Medication. Subjects were two groups, confirmed to Soyangin Heat-related diarrhea accompanied by headache and Soyangin Cold-related diarrhea accompanied by abdominal pain. All subjects answered the questionnaire about their Original symptoms. We found the differences between 2 groups using the Independent-Samples T-test. Analysis was conducted using SPSS 12.0 for Korean. 3. Results and Conclusions: In Original symptoms, Tendency of overeating(p=0.01), Condition of digestion(p=0.04), Perspiration after exercise (p=0.02), Usual perspiration(p=0.00), Tiredness after perspiration(p=0.05) Cold intolerance on extremities(p=0.04), General edema(p=0.01) etc. are different between 2 groups. We found the differences of heat and cold in symptoms between two Soyangin syndromes.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.30 no.4
• /
• pp.45-58
• /
• 2017

Objectives: The aim of this trial is to investigate the effect of Ginseng and Wild Cultivated Ginseng to Heat pattern subject. Methods: Eighty-nine Subjects were diagnosed as heat pattern by Cold-Heat Patternization and divided into Ginseng group (n=30), Wild Cultivated Ginseng group (n=31) and Placebo group (n=28) in their 1 st visit. In each visit, The researchers measured the subject's facial temperature using the infrared thermometer (Testo 835-T1). After that, The subjects were asked to mark the current score of flushing on the Visual Analogue Scale (VAS) and to complete the Chalder-Fatigue Scale (CFS) in each visit. The subjects took the test drug for one week and returned the remaining drug on the 2nd visit. The trial result was analyzed with one-way ANOVA using SPSS for Windows version 18. Results: 1. Systolic blood pressure was significantly lower in the Ginseng group and Wild Cultivated Ginseng group than in the control group (p=0.021). 2. There was no significant difference in facial temperature between each groups. 3. The current score of flushing showed the greatest decrease in the Ginseng group compared to the other groups but there was no significant difference (p=0.205). 4. The score of Chalder-Fatigue Scale was decreased in all groups but not statistically significant (p=0.180). Conclusions: This study showed that taking Ginseng extract and Wild Cultivated Ginseng extract do not affect to heat-rising reaction to the subjects diagnosed as heat pattern.

• Journal of Korean Medicine for Obesity Research
• /
• v.11 no.1
• /
• pp.25-34
• /
• 2011

Objectives The purpose of this study was to examine the characteristics of diagnostic pattern questionnaire associated with Body Mass Index in premenopausal women. Methods We studied 41 patients visiting Gangdong Kyung Hee University Hospital from 1st April 2011 to 25th May 2011. The subjects were categorized in two groups, overweight & obesity group (n=12) and low weight & normal group (n=29). We studied the difference of diagnostic pattern questionnaire scores between two groups by Independent samples T-test and correlation between diagnostic pattern questionnaire scores of overweight & obesity group by Pearson's correlation coefficient test using SPSS for windows (version 13.0). Results Blood stasis, retention of undigested food, cold pattern scores of overweight & obesity group were non-significantly higher than low weight & normal group. Heat pattern score of overweight & obesity group was significantly higher than low weight & normal group. Cold-heat, phlegm-cold, blood stasis-cold, phlegm-blood stasis, phlegm-retention of undigested food significantly showed positive correlation coefficient in overweight & obesity group. Conclusions The results suggest that obese women tend to show heat pattern. It seems to be that multiple factors such as phlegm, blood stasis, retention of undigested food are causative of obesity.

• Journal of Applied Reliability
• /
• v.9 no.2
• /
• pp.81-91
• /
• 2009

This paper presents the comparison of climatic environmental tests of IEC Pub. 60068 and MIL-STD-810. Cold, dry heat, change of temperature, and heat-humidity cyclic tests are compared in terms of the types of tests and test severities. This study shows the difference between the standards, which will provide the useful information to the industries and be helpful in applying the standards.