• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.876-881
• /
• 2001

DLC(Diamond-like carbon) films possess high hardness, low friction coefficient, and good wear resistance. Due to these properties, DLC films have been used extensively in magnetic hard disk industry. The objective of the present study was to investigate the influence of environmental condition on the tribological behavior of DLC coated hard disk. It is found that the tribological characteristics of DLC films are strongly affected by relative humidity and temperature. Specifically, the friction coefficient increases with increase in temperature at relative humidity of 50%. However, at 20% and 85% RH the effect of temperature was not significant. Also, the degree of wear could be observed using an AFM.

• 대한전기학회논문지
• /
• 제45권1호
• /
• pp.93-99
• /
• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• 한국환경복원기술학회지
• /
• 제5권2호
• /
• pp.34-38
• /
• 2002

자생 양치식물중 실내식물로서 개발가치가 높은 가는쇠고사리(Arachniodes aristata )와 석위(Pyrrosia lingua)의 실내 습도조건에 따른 생육 반응을 살펴보고자 수행하였으며, 그 결과는 다음과 같다. 1. 가는고사리와 석위는 상대습도 50%, 90% 보다 25%와 같은 저습도시 식물체내수분함량, 엽록소함량, 관상가치가 저하되었다. 2. 상대습도에 대한 용토별 생육에 있어 고습도인 90%일시 용토별 생육에는 큰 차이가 나타나지 않았으나, 중습도인 50%일 경우 일반 토양이 가장 좋은 것으로 나타났다. 저습도인 25%의 경우 가는쇠고사리는 인공배합토에서, 석위는 일반토양에서 생육이 좋은 것으로 나타났다.

• Journal of Biosystems Engineering
• /
• 제11권1호
• /
• pp.52-63
• /
• 1986

This study was performed to find out drying characteristics and develop drying model for the design of an efficient dryer or drying system of red peper. The basic model which describes drying phenomenon of red pepper was firstly established, and drying tests were conducted at 14-different drying conditions. In this test, the effects of drying air temperature and relative humidity on the rate of drying were undertaken. Finally, a new drying model based on these experimental results was developed to describe the drying characteristics of red pepper. The results from this study may be summarized as follows. 1. Drying constant of the basic model established from Lewis' experimental model and diffusion equation was theoretically deduced as a function of moisture content and inner-temperature of red pepper. 2. From the results of drying tests, drying air temperature was found to have the greatest effect on the rate of drying. However, the effect of temperature was small for the condition of high relative humidity, and for low temperature, the effect of relative humidity was found to be large even though the range of relative humidity was low. 3. Modified Henderson equation was found to be better than Chung equation as the EMC model for the estimation of the equilibrium moisture content of red Pepper. 4. Constant-rate drying period did not exist in the red pepper drying test. And falling-rate drying period was divided into three distinct phases. Drying rate was dependent on the moisture content, the inner-temperature of red pepper and the change of physical property due to drying. 5. Drying constant increased with decrease of free moisture content, but it decreased at the end of the drying period. Also, drying constant was dependent on the drying air temperature and relative humidity. 6. The new drying model developed in this study was found to be most suitable in describing the drying characteristics of red pepper. Therefore, it may be concluded that drying time could be accurately estimated by the new drying model.

• Journal of the Korean Wood Science and Technology
• /
• 제35권5호
• /
• pp.7-15
• /
• 2007

To evaluate the durability of finger-jointed woods according to change of humidity conditions, four types of finger-jointed woods glued with different kinds of adhesives and finger pitches were made with Sitka spruce, and the effect of humidity conditions on creep performances was investigated. The shape of creep curves differed among humidity conditions, and the inclination of creep curves was greatest in 85%RH, and lowest in 65%RH. Their creep curves showed a linear behavior beyond approximately one hour, regardless of humidity conditions. The A values of the creep curves fitted to power law increased with increasing relative humidity, whereas the A' values were in order of 30 > 85 > 65%RH unlike the A values. The initial deformation increased with increasing relative humidity, whereas the creep deformation unlike the initial deformation was in order of 85 > 30 > 65%RH, and it was found that the creep deformation of finger-jointed woods indicated the smaller amount in air-dry moisture content rather than in a low moisture content less than 30%RH. Finger-jointed woods with 6.8 mm (L) pitch had the greater creep amount than in those with 4.4 mm (S) pitch in all humidity conditions. The difference of creep amount between both adhesives in all humidity conditions was small. Relative creep at 240 hr was greatest as 62.2~71.9% in 85%RH, and the values indicated 2.1~2.6 times that of 30%RH and 3.0~3.6 times that of 65%RH and were equal or slightly greater than that of solid spruce.

• Journal of Veterinary Science
• /
• 제25권3호
• /
• pp.24.1-24.9
• /
• 2024

Importance: In veterinary forensic science, accurately determining the postmortem interval (PMI) is crucial for identifying the causes of animal deaths. Autolysis, a significant postmortem process, influences PMI estimation, but its relationship with humidity is not well understood. Objective: This study aimed to improve the accuracy of PMI estimates in veterinary forensic cases by looking into how different humidity levels affect autolysis in different organs of rats. Methods: The study involved 38 male rats, examining histopathological changes in their heart, liver, and pancreas. These organs were subjected to controlled humidity levels (20%, 55%, and 80%) at a constant 22℃. Tissue samples were collected at several intervals (0 h, 12 h, 24 h, 3 days, and 8 days) for comprehensive analysis. Results: Distinct autolytic characteristics in animal organs emerged under varying humidity conditions. The low-humidity environment rapidly activated autolysis more than the high-humidity environment. In addition, it was found that lower humidity caused nuclear pyknosis, cytoplasmic disintegration, and myofiber interruption. The liver, in particular, showed portal triad aggregation and hepatocyte individuation. The pancreas experienced cell fragmentation and an enlarged intracellular space. High humidity also caused the loss of striations in cardiac tissues, and the liver showed vacuolation. Under these conditions, the pancreas changed eosinophilic secretory granules. Conclusions and Relevance: The study successfully established a clear connection between the autolytic process in PMIs and relative humidity. These findings are significant for developing a more accurate and predictable method for PMI estimation in the field of veterinary forensic science.

• 한국환경과학회지
• /
• 제31권4호
• /
• pp.311-318
• /
• 2022

In this study, we analyzed the relationships between weather factors and photosystem II activity (F_v/F_m), as a measure of photochemical efficiency, in three cool-season turfgrasses commonly planted on golf courses in Jeju, South Korea: perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In all three turfgrasses, F_v/F_m was higher during late summer than during early summer. However, in late summer, F_v/F_m was significantly lower in perennial ryegrass than in the other two species. In early summer, F_v/F_m in perennial ryegrass and Kentucky bluegrass was positively correlated with mean low temperature and extreme minimum temperature, whereas, in late summer, this parameter in Kentucky bluegrass and creeping bentgrass was positively correlated with relative humidity, and in creeping bentgrass was negatively correlated with mean high temperature, mean low temperature, and extreme maximum temperature. These results indicate that raising low temperatures is favorable for perennial ryegrass and Kentucky bluegrass in early summer, whereas, in late summer, the lowering of high temperatures proves to be beneficial for creeping bentgrass, and raising relative humidity is conducive to the growth of Kentucky bluegrass and creeping bentgrass. These findings will contribute to improving the selection and management of turfgrasses on golf courses and sports fields.

• 한국입자에어로졸학회지
• /
• 제18권4호
• /
• pp.109-127
• /
• 2022

Recently, low-cost particulate matter (PM) sensors have been widely used in monitoring mass concentration. Maintaining the accuracy of the sensors is important and requires rigorous performance evaluation and calibration. In this study, two commercial low-cost PM sensors(LCS), Plantower PMS3003 and Plantower PMS7003, were evaluated in the laboratory and field with a reference-grade PM monitor (GRIMM 11-D). Laboratory evaluation was conducted with single/mixed particles of PSL (Poly Styrene Latex) in an acrylic chamber at 20℃ and relative humidity of 20%. Field evaluation was conducted inside a building of Yonsei University (Shinchon) from February 12 to March 31, 2022. In both evaluations, LCS measured values became different from reference measured values when the relative humidity was high or the outdoor air PM10/PM2.5 ratio was high. Based on the field evaluation, the LCS measured values were corrected through four different regression analysis models. As a result, the multivariate polynomial regression analysis model showed highest matching with the reference PM monitor (PM2.5 >0.9, PM10 >0.85). In this model, the PM10/PM2.5 ratio and relative humidity were chosen as independent variables.

• 한국식품과학회지
• /
• 제19권2호
• /
• pp.176-180
• /
• 1987

건조마늘 플레이크를 상대습도 11%에서 84%까지 7단계의 상대습도별로$5^{\circ}C$, $20^{\circ}C$ 및 $35^{\circ}C$온도에 저장하면서 건조마늘 플레이크의 갈변 및 흡습특성을 조사하였다. 저장시간에 따른 건조마늘 플레이크의 흡습곡선은 RH 51% 이하에서는 단시간내에 평형에 도달하여 수분함량의 변화가 거의 없었으나, $20^{\circ}C$ 및 $35^{\circ}C$의 RH 67% 이상에서 $5^{\circ}C$의 RH 84%에서 평형수분함량이 급격히 증가하여 갈변현상이 나타났다. 건조마늘 플레이크의 단분자층 수분함량은 온도에 따라서 5.80%(DB)에서 6.20%(DB)로서 온도가 내려감에 따라 다소 증가하는 경향을 나타냈고 수분함량 및 저장온도가 낮으면 낮을수록 흡습력이 크기 때문에 건조마늘 플레이크의 장기저장에 방습포장재가 필요하였다. 상대습도 및 저장온도에 따라서 건조마늘 플레이크의 갈변도를 예측할 수 있는 회귀방정식을 도출하였다.

• 보존과학회지
• /
• 제29권4호
• /
• pp.421-435
• /
• 2013

본 연구는 수중 발굴 도자기에 있어 상대습도 조건에 따른 수용성 염의 표면거동을 조사하여 도자기 보존관리에 적합한 환경기준을 제시하고자 한다. 실험 24주간 전기전도도 누적총량(${\mu}s/cm$)으로 [고습조건(RH70%+RH80%)/저습조건(RH20%+RH40%)]의 상대적 비율 분석결과, 고습조건이 저습조건에 비해 이온용출량이 증가하였고, 특히 청자 시료의 경우 그 증가폭이 두드러졌다. 또한 고습조건 시편들의 전기전도도 누적총량을 시료의 물리적 특성과 비교한 결과, 이온용출량은 시료의 흡수율 및 기공률의 증가에 따라 비례하였다. 수중 발굴 도자기는 매장환경의 특성상 염에 의한 물리 화학적 손상 및 2차오염이 크게 우려된다. 따라서 도자기의 이상적인 보존에는 습도변화에 비교적 안정적인 저습조건의 항온항습 수장고가 권장되며, 수장고 설비에 있어 시료의 재질특성에 따른 사전분류가 선행될 필요가 있다.