• Steel and Composite Structures
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• 제46권4호
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• pp.577-589
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• 2023

In this study, on-site testing was carried out to investigate the vibration performance of a cold-formed thin-walled steel floor system. Ambient vibration, walking excitation (single and double persons), and impulsive excitation (heel-drop and jumping) were considered to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes) and vertical acceleration response. Meanwhile, to discuss the influence of cement fiberboard on structural vibration, the primary vibration parameters were compared between the systems with and without the installation of cement fiberboard. Based on the experimental analysis, the cold-formed thin-walled steel floor possesses high frequency (> 10 Hz) and damping (> 2%); the installed cement fiberboard mainly increases the mass of floor system without effectively increasing the floor stiffness and may reduce the effects of primary vibration parameters on acceleration response; and the human-structure interaction should be considered when analyzing the vibration serviceability. The comparison of the experimental results with those in the AISC Design Guide indicates that the cold-formed thin-walled steel floor exhibits acceptable vibration serviceability. A crest factor 𝛽_rp (ratio of peak to root-mean-square accelerations) is proposed to determine the root-mean-square acceleration for convenience.

• Human Ecology Research
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• 제62권2호
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• pp.317-326
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• 2024

This study evaluated the thermal physiological and psychological responses elicited when wearing cold protective jackets with aerogel fillings in two cold environments, one without air velocities and one with air velocities (2.3 m·s-1), at an air temperature of 10℃. The participants were five healthy young males. Measures were taken of physiological parameters, blood pressure (BP), heart rate (HR), core temperature, oxygen uptake (Vo2), and microclimate (temperature and humidity). The psychological parameters evaluated were thermal and wetness sensation. No differences were observed in systolic blood pressure, heart rate, and oxygen intake between the conditions. At tympanic temperature, a significant difference was observed between the conditions during exercise (p<.05); . A significant difference was observed in the microclimate temperature of the clothing according to the airflow, and temperature changes in the chest and back revealed different patterns. Significant differences were observed in thermal sensation (whole body (p<.05), chest (p<.05), back (p<.01)) between airflow conditions. The results therefore indicate that cold protective jackets with an aerogel filling are suitable for people operating in low-temperature and airflow environments.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.374-380
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• 1996

Sprague-Dawley male rats (150 g) were chronically treated with 5 v/v % ethanol admixed with nutritionally complete liquid diet and fed ad libitum for 3 weeks. One half of each group was exposed to cold stress at 4 ^{\circ}C either for 24 h (for determination of mRNA by in situ hybridization) or for 48 h (for determination of enzyme activity). Chronic ethanol treatment (ethanol) did not affect tyrosine hydroxylase(TH) mRNA level in locus coeruleus(LC) of brain and adrenal medulla(AM) compared to controls. Cold stress showed strong increase of TH mRNA level in LC and AM compared to controls. Pretreated ethanol reduced the increased TH mRNA level by cold stress in LC and AM. Ethanol did not affect TH activity in LC and adenal glands(adrenals). Cold stress increased TH activity in LC but not in adrenals. Pretreated ethanol did not reduce the increased TH activity by cold stress in LC but this result was not shown in adrenals. Phenylethanolamine-N-methyltransferase(PNMT) activity in $C_{1}$$C_{2}$ and adrenals increased only in ethanol treated group. THese results suggest that ethanol does not affect TH mRNA level and activity in LC and adrenals, but increases PNMT activity in $C_{1}$$C_{2}$ and adrenals in normal rat. It is also suggested that pretreated ethanol reduces the magnitude of cold stress response, that is induction of TH mRNA in LC and AM, and does not reduce the protein activation of TH that is also cold stress response in LC.

• 대한기계학회논문집B
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• 제33권2호
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• pp.133-140
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• 2009

A fast-response $CO_2$ analyzer has been developed for measuring the $CO_2$ concentration during transient condition of a SI engine. The analyzer consists of the non-dispersive infrared absorption method, electrical chopping system and water cooling system. The analyzer has good repeatability, linearity and permissible drift characteristic. Besides, it showed 18ms of a response to measure the $CO_2$ concentration. The fast-response $CO_2$ analyzer was applied to a single cylinder SI engine and the $CO_2$ emission was examined during engine start. Simultaneously, the standard exhaust gas analyzer, which has slow response time, was used for confirming the accuracy of the exhaust gas analysis using the fast-response $CO_2$ analyzer. The developed analyzer showed much faster responsive characteristic than that of a standard analyzer and made cycle by cycle exhaust gas analysis possible. The transient engine operating characteristics will be estimated from the $CO_2$ concentration of engine-out emissions and engine operating variables.

• Genomics & Informatics
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• 제19권4호
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• pp.45.1-45.8
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• 2021

Brassica napus is the third most important oilseed crop in the world; however, in Korea, it is greatly affected by cold stress, limiting seed growth and production. Plants have developed specific stress responses that are generally divided into three categories: cold-stress signaling, transcriptional/post-transcriptional regulation, and stress-response mechanisms. Large numbers of functional and regulatory proteins are involved in these processes when triggered by cold stress. Here, our objective was to investigate the different genetic factors involved in the cold-stress responses of B. napus. Consequently, we treated the Korean B. napus cultivar Naehan at the 4-week stage in cold chambers under different conditions, and RNA and cDNA were obtained. An in silico analysis included 80 cold-responsive genes downloaded from the National Center for Biotechnology Information (NCBI) database. Expression levels were assessed by reverse transcription polymerase chain reaction, and 14 cold-triggered genes were identified under cold-stress conditions. The most significant genes encoded zinc-finger proteins (33.7%), followed by MYB transcription factors (7.5%). In the future, we will select genes appropriate for improving the cold tolerance of B. napus.

• 수산해양교육연구
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• 제26권5호
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• pp.979-990
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• 2014

Recently the frequency of coastal disasters caused by global warming is increasing and the damage is becoming greater. Therefore, the Korean government is establishing various policies and measures to minimize damage. For disaster prevention, this study will evaluate the disaster response capacity of each local resident(Eup/Myeun/Dong) in coastal areas through the survey. The purpose of this study is to quantitatively understand the disaster response capacity and analyze spatial autocorrelation between hot spots(vulnerable area) and cold spots. Thus this study was conducted a survey of 311 towns(Eup/Myeun/Dong) about the disaster response capacity of coastal residents. As a result, Namhae has the highest average score(4.9). On the contrary, Hampyeong has the lowest(1.6). Coastal residents in Namhae seem to have better understanding of first aid and preventive maintenance. But coastal residents in Hampyeong seem to not have these characteristics. Afterwards, this study builds a database of disaster response capacity, and analyzes it using the spatial autocorrelation method. Finally, the area of hot spots and cold spots for disaster response capacity was quantitatively detected.

• 해양환경안전학회지
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• 제27권6호
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• pp.701-707
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• 2021

본 연구에서는 강한 한파가 발생했던 2018년과 온난 한파가 발생했던 2019년의 기온에 따른 수온의 반응 및 지연시간과 북풍계열 바람 빈도와의 상관관계를 분석하였다. 사용된 시간 자료는 국립수산과학원에서 제공하는 7개 지점 해역별 수온자료와 수온관측소 인근 7개 지점 AWS 기온자료를 이용하였다. 관측되지 못한 자료는 내삽법으로 근사값을 계산하였고, FIR Filter를 이용하여 자료의 주기성을 파악하였다. 그 결과, 강한 한파가 발생했던 2018년은 북풍계열 바람을 통해 차가운 공기가 남하하면서 기온을 하강시켜 전 해역에 저수온을 유발한 반면 온난 한파가 발생했던 2019년은 평년 수준의 기온으로 하강하였지만 수온은 크게 변화하지 않았다. 강한 한파가 발생했던 2018년 기온 하강에 따른 수온의 지연시간은 평균 14시간으로 0.7 이상의 높은 상관성을 나타냈고 온난 한파가 발생했던 2019년은 평균 지연시간이 20시간으로 0.44-0.67 사이의 상관성을 보였다. 본 연구를 통해 해역별로 기온 하강에 따른 표층수온의 반응을 해석하였고 지연시간을 파악함으로써 양식생물의 피해를 최소화하고 한파 피해의 신속한 대응에 기여할 수 것으로 기대한다.

• Steel and Composite Structures
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• 제6권6호
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• pp.513-529
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• 2006

This paper deals with the dynamic behaviour of cold-formed steel hollow frames with different connection stiffnesses. An analytical model of a semi-rigid frame was developed to study the influence of connection stiffnesses on the fundamental frequency and dynamic response of the frames. The flexibilities of the connections are modeled by rotational springs. Neglect of semi-rigidity leads to an artificial stiffening of frames resulting in shorter fundamental period, which in turn results in a significant error in the evaluation of dynamic loads. In the seismic design of structures, of all the principal modes, the fundamental mode of translational vibration is the most critical. Hence, experiments were conducted to study the influence of the connection stiffnesses on the fundamental mode of translational vibration of the steel hollow frames. From the experimental study it was found that the fundamental frequency of the frames lie in the semi-rigid region. From the theoretical investigation it was found that the flexibly connected frames subjected to lateral loads exhibit larger deflection as compared to rigidly connected frames.

• 대한한방내과학회지
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• 제35권1호
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• pp.50-58
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• 2014

Objectives : The aim of this study was to analyze relationship between post-stroke depression (PSD) and cold, heat, deficiency and excess patterns. Methods : Twenty-eight PSD patients were recruited from STROKE center and measured with questionnaires for cold, heat, deficiency and excess patternvalues and saliva for cortisol awakening response (CAR). Saliva samples were collected immediately, 15, 30 and 45 min after awakening. In addition, Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS) were conducted for PSD severity. We conducted correlation analysis to find the relationship between cold, heat, deficiency and excess patterns and CAR or BDI and HDRS. Results : Deficiency and excess patterns werepositively correlated with area under the curve with respect to the increase (AUCi), but not with area under the curve with respect to the global (AUCg), in CAR. Furthermore, it was negatively correlated with BDI and HDRS, while cold and heat patterns were not correlated with CAR, BDI and HDRS. Conclusions : In terms of deficiency and excess patterns, the higher the PSD severity, the higher the deficiency and the lower the PSD severity, the higher the excess. However, there was not a significant relationship between PSD and cold and heat patterns.

• 대한한방부인과학회지
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• 제18권3호
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• pp.51-66
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• 2005

Purpose : Investigate the effects of Haeganjeon water extract (HGJ) on immobilization-stress or cold-stress in C57BL/6J mice. Methods : Male C57BL/6J 30 mice of weighting 18${\pm}$2g, were divided into sixs groups including the immobilization-stress group(5heads), after immobilization-stress HGJ oral administration(500mg/kg) groups(5heads), cold-stress group(5heads) and after cold-stress HGJ oral administration(500mg/kg) groups(5heads). then we observed changes in the serum histamine and corticosterone level and changes immune system. Results : HGJ decreased the serum level of histamine and corticosterone increased by immobilization-stress or cold-stress. HGJ inhibited the release of histamine from mast cells. In addition, HGJ enhanced the cell viability of thymocytes decreased by immobilization-stress or cold-stress and decreased DNA fragmentation of thymocytes increased by immobilization- stress or cold-stress. Also, HGJ increased the cell viability of splenocytes decreased by cold-stress and decreased DNA fragmentation of splenocytes increased by cold-stress. HGJ decreased the population of thymic CD4+ cells increased by immobolization-stress. HGJ increased the population of B220+ cells decreased by immobilization-stress and decreased the population of Thy1+ cells increased by immobilization-stress. Also, HGJ decreased the population of splenic CD4+ cells increased by immobolization-stress. HGJ enhanced the production of ${\gamma}-interferon$ decreased by immobilization-stress or cold-stress and increased the production of interleukin-4 decreased by immobilization-stress. Furthermore, HGJ enhanced the phagocytic activity decreased by immobilization-stress or cold-stress and enhanced the level of nitric oxide decreased by immobilization-stress or cold-stress. Conclusion : HGJ may be useful for the prevention and treatment of stress via suppression of serum histamine and corticosterone level and enhancement of immune response.