• Korean Journal of Acupuncture
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• v.26 no.4
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• pp.23-38
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• 2009

Objectives : The purpose of this study was to identify the effect of the tonification & sedation manipulation for LI4 and KI7 on lacking of sweating in cold environment. Methods: The participants were divided into 3 groups as intact group without acupuncture, acupuncture group inserting and twisting with LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) and acupuncture group inserting and twisting with LI4 sedation and KI7 tonificaton method(LI4-purge KI7-tonify). We obtained baseline data at cold condition with the temperature $14{\pm}1^{\circ}C$. After making the participant staying in cold condition for 10 minute, we measured sweating rate in skin surface, body temperature, oxygen saturation, pulse rate, systolic blood pressure, diastolic blood pressure, deoxy-Hb and oxy-Hb in subcutaneous. Results : After acupuncture in cold environment, the sweating rate in skin surface significantly decreased in KI7-purge LI4-tonify group comparing the intact groups. The body temperature significantly increased in LI4-tonify KI7-purge and LI4-purge KI7-tonify groups comparing the intact group. The oxygen saturation significantly increased in LI4-tonify KI7-purge group comparing the intact group. Conclusions : These findings indicated that LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) could be effective for production of sweating in cold condition.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.622-629
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• 2007

Some worker is occupationally exposed to cold and freezing environment. The cold stimuli in the working environment impose physiological and psychological loads on workers to decrease the task performance. The purpose of this study is to investigate the cold stimuli of cold and freezing stores widely used in Busan can make an effect on human's physiological responses and task performance, experimentally and analytically. In the experiment, 5 workers are selected as subjects, and then their skin temperatures of hand and ear, heart rates, blood pressure, and ring test performances in cold($3^{\circ}C$) and freezing($-22^{\circ}C$) stores were measured for 21 minutes and analyzed by using statistical method. It is observed that a physiological variation and the task performance are significantly influenced by an exposure time as well as a strength of cold stimuli. Also, it is suggested the exposure limiting times for the useful manual work and the performance predict model of the ring tasks. The result of this study will be useful for a fundamental data of which design the standard task time of manual tasks and solve the job placement problem of worker selection and placement in cold environment.

• Journal of Hydrogen and New Energy
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• v.30 no.3
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• pp.276-281
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• 2019

The process of separating oxygen and nitrogen from the air is mainly performed by electric liquefaction, which consumes a lot of electricity, resulting in higher operating costs. On the other hand, when used for cold energy of LNG, electric power can be reduced compared to the electric Linde cycle. Currently, LNG cold energy is used in the cold refrigeration warehouse, separation of air-liquefaction, and LNG cold energy generation in Japan. In this study, the system using LNG cold energy and the Linde cycle process system were simulated by PRO/II simulators, respectively, to cool the elevated air temperature from the compressor to about $-183^{\circ}C$ in the air liquefaction separation process. The required amount of electricity was compared with the latent heat utilization fraction of LNG, the LNG supply pressure, and the LNG cold energy usage. At the air flow rate of $17,600m^3/h$, the power source unit of the Linde cycle system was $0.77kWh/m^3$, compared with $0.3kWh/m^3$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.76-81
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• 2009

A nonlinear pressure controller to actively regulate the thrust of a solid propulsion system is presented. To compensate for the parametric uncertainties with respect to the chamber pressure induced by changing nozzle throat area, Lyapunov-based parameter adaptation method has been applied. In order to verify the effectiveness of the proposed control method, the experiments were carried out using the cold gas test equipment that can simulate the operating environment of variable thrust solid propulsion system. The experiment results show that the nonlinear pressure controller has better performance than conventional P and PI controller.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.127-132
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• 2005

We investigated whether ischemic preconditioning (IPC) protects liver against cold ischemic injury using isolated perfused rat liver. Rat livers were preconditioned by 5 minutes of ischemia and 5 minutes of reperfusion and preserved for 30 hours at $4^{\circ}C$ in University of Wisconsin solution. Livers were then reperfused for 120 minutes. Oxygen uptake and bile flow in ischemic livers markedly decreased during reperfusion. These decreases were prevented by IPC. Portal pressure was elevated in cold ischemic and reperfused livers and this elevation was prevented by IPC. Lactate dehydrogenase and purine nucleoside phosphorylase activities markedly increased during reperfusion. These increases were prevented by IPC. The ratio of reduced glutathione to glutathione disulfide was lower in ischemic livers. This decrease was prevented by IPe. Our findings suggest that IPC protects the liver against the deleterious effect of cold ischemia/reperfusion, and this protection is associated with the reduced oxidative stress.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.233-234
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• 2006

LNG is extremely cold, $-160^{\circ}C$ in its liquid state. When it vaporizes, returning to its natural state (re-vaporization), it cools its surroundings. This is cold energy. The manufacturing of liquid air is the first processes developed as the most effective utilization of LNG cold. In this paper, adopting the LNG cold process for manufacturing liquid air was developed and analysed. The result showed that as the higher air pressure and adapting nitrogen precooling, liquefaction rate and cumulative mass was increased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.384-389
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• 2005

Experimental study of variation of exhaust gas temperature was carried out with the changes of spark timing and exhaust valve timing during the cold start operation of an SI engine. To investigate the effects of these variables on combustion stability, cylinder pressure and exhaust gas temperature were measured and analyzed. Experimental results showed that exhaust gas temperature increased when spark and exhaust valve timings were retarded from the baseline cases. However, combustion stability during cold start deteriorated under the retarded conditions. To increase exhaust gas temperature for fast warmup of catalysts while maintaining combustion stability, an optimal condition for spark and valve timing retard should be appied for the cold start period.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.4
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• pp.101-108
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• 2011

On cold start operation of an SI engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.65-73
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• 2022

The proper estimation of physical and chemical properties of Earth materials and their structures at high pressure and high temperature conditions is key to the full understanding of diverse geological processes in Earth and planetary interiors. Multi-anvil press - high-pressure generating device - provides unique information of Earth materials under compression, mainly relevant to Earth's upper mantle. The quantitative estimation of the relationship between the oil load within press and the actual pressure conditions within the sample needs to be established to infer the planetary processes. Such pressure-load calibration has often been based on the phase transitions of crystalline earth materials with known pressure conditions; however, unlike at high temperature conditions, phase transitions at low (or room) temperatures can be sluggish, making the calibration at such conditions challenging. In this study, we explored the changes in Al coordination environments of permanently densified pyrope glasses upon the cold compression using the high-resolution ²⁷Al MAS and 3QMAS NMR. The fractions of highly coordinated Al in the cold compressed pyrope glasses increase with increasing oil load and thus, the peak pressure condition. Based on known relationship between the peak pressure and the Al coordination environment in the compressed pyrope glasses at room temperature, we established a room temperature pressure-load calibration of the 14/8 HT assembly in 1,100-ton multi-anvil press. The current results highlight the first pressure-load calibration of any high pressure device using high-resolution NMR. Irreversible structural densification upon cold compression observed for the pyrope glasses provides insights into the deformation and densification mechanisms of amorphous earth materials at low temperature and high pressure conditions within the subducting slabs.

• The Korean Journal of Quaternary Research
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• v.33 no.1_2
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• pp.37-48
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• 2021

The cold surge is an important extreme weather in East Asia during winter, and is largely affected by behavior of the Siberian high Arctic Oscillation, which represents undulation of large-scale pressure pattern in the Arctic region. Recent studies also revealed that the synoptic low pressure system developing in the eastern boundary of the Asian continent is sensitive to sea surface temperature (SST) and plays an important role in strengthening the cold advection over the Korean Peninsula during cold surges. In this study, we analyzed the Arctic Oscillation affecting the large-scale background of cold surge in East Asia, and the sea surface temperature in the coast of East Asia is examined focusing on its role on synoptic low-inducing cold advection. For the analysis, the days with the bottom 3% of the average daily temperature, measured at five surface stations in Korean Peninsula during 49 years (1969/70-2017/18), were used for the cold surge cases. During the negative phase of the Arctic Oscillation, a strong trough is observed over East Asia, and the inflow of cold air from the polar region is strengthened, which lead to frequent cold surges. In addition, anomalously high SST in the eastern coast of Asia increases sensible and latent heat release from the ocean, therefore, it enlarges the likelihood of synoptic low-inducing extreme cold surges.