• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.53 no.1
• /
• pp.19-40
• /
• 2017

A scientific and objective sound exposure criterion for underwater sound damage on fish has been required since there has been many disputes between an underwater sound maker and a fish damage receiver. The existing criteria are still incomplete scientifically owing to a degree of variability of underwater sounds, diversity of fish hearing sensitivity and damage types, etc. This study reviews existing studies on a hearing mechanism of fish species, manmade underwater sound characteristics and sound exposure assessment parameters, and recent sound exposure criteria. A governing equation for damage coverage estimation and damage coverage dependency on sound source level, ambient noise and transmission loss are also reviewed and interpreted based on sound exposure environments. The foreign and Korean (National Environmental Dispute Medication Commission) criteria are reviewed and compared based on scientific aspects. In addition, the deficit and limit of Korean criteria are presented. The objective of this study is to give a direction for related researches and legislation of sound exposure criteria on fish.

• Journal of Environmental Health Sciences
• /
• v.26 no.4
• /
• pp.58-64
• /
• 2000

Indoor air quality tends to be the dominant contributor to personal exposure, because most people spend over 80% of their time indoors. In this study, indoor and outdoor NO$_2$ concentrations were measured and compared with simultaneously personal exposures of 21 university students in weekday and weekend. House characteristics and activity pattern were used to determine the impacts of these factors on personal exposure. Since university students spent most of their times in indoor, their NO$_2$ exposure was associated with indoor NO$_2$ level rather than outdoor NO$_2$ level both weekday and weekend in spite of different time activity. Using time-weighted average model, NO$_2$ exposures of university students were estimated by NO$_2$ measurements in indoor home, indoor school, and outdoor home levels. Estimated NO$_2$ personal exposures were significantly correlated with measured NO$_2$ personal exposures($r^2$=0.87). However, estimated personal NO$_2$ exposures by time-weighted average model were underestimated, comparing with the measured personal NO$_2$ exposure. Using multiple regression analysis, effect of personal NO$_2$ exposure for transportation was confirmed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.04b
• /
• pp.118-120
• /
• 2002

Electro-optical (EO) characteristics of the ion beam (IB) aligned twisted nematic (TN)-liquid crystal display (LCD) with oblique ion beam exposure on the diamond-like carbon (DLC) thin film surface were studied. An excellent voltage-transmittance (V-T) curve of the ion beam aligned IN-LCD was observed with oblique ion beam exposure on the DLC thin film surface for I min. Also, a faster response time for the ion beam aligned TN-LCD with oblique ion beam exposure on the DLC thin film surface for 1 min can be achieved.

• Korean Journal of Occupational Health Nursing
• /
• v.31 no.2
• /
• pp.95-103
• /
• 2022

Purpose: This study aims to identify general, workplace, and health-related characteristics of outdoor workers exposed to high temperatures, and to compare the risk of disease according to outdoor high temperature exposure. Methods: This secondary analysis study used the 5th Korean Working Conditions Survey (2017) to identify 4,915 outdoor workers exposed to high temperatures. Results: Outdoor workers exposed to high temperatures were mostly male, elderly, less educated, and daily contract workers. Most of them were engaged in agriculture, forestry and fishing, and construction industries. About 40~50% of them complained of musculoskeletal pain and overall fatigue. The results showed that high temperature exposure increased the risk of illness (hearing problem, skin problem, backache, muscular pains in upper and lower limbs, headache/eyestrain, injuries, depression, and overall fatigue) among workers. Conclusion: High temperature exposure might increase the risk of illness among workers. The results of this study demonstrated that the outdoor workers should be protected from high temperatures.

• Anxiety and mood
• /
• v.16 no.1
• /
• pp.1-8
• /
• 2020

Objective : This study aims to examine the association between exposure to suicide events and suicide ideation by analyzing the levels of suicide ideation among the groups with exposure to suicide death, non-suicide death, and no death in their social relationships. Methods : Data were derived from Wave I of the Longitudinal Study of Suicide Survivors' Mental Health. 1,998 adults nationwide selected using a stratified sampling method based on the Korean Census Data, were categorized into 3 groups with exposure to suicidal death, non-suicidal death, and no death. The levels of depression (Brief CES-D), subjective health status, and suicidal ideation (SSI) were measured. To examine the association between exposure to suicide and the level of suicide ideation, multiple regression analysis was used after controlling the socio-demographic and clinical factors including subjective health status and depression. Results : 32% reported their exposure to suicide. Compared to the other groups, the suicide-exposed group's level of depression and suicide ideation were significantly higher but the subjective health status was lower. Multiple regression model revealed that suicide exposure had a statistically significant association with suicidal ideation at p=0.000 even after controlling the clinical characteristics. Conclusion : HThe findings suggest that exposure to suicide is a risk factor for suicidal ideation. In the clinical field, it is necessary to consider patients' experience in exposure to suicide while treating and intervening in suicide-related cases. At the policy level, a mental health system for suicide prevention should consider this risk factor for those exposed to suicide in their family and social relationships.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.34 no.2
• /
• pp.156-165
• /
• 2024

Objectives: This study aims to identify and analyze the exposure status of welding students in specialized high school welding labratories, compare it with the exposure to welding hazards of industrial workers, and seek to improve the educational environment for youth through domestic and international exposure standards. Methods: This study compares the level of exposure to hazardous factors in a welding laboratory of a vocational high school in Jeollanam-do and a welding process in a general industrial site by measuring the work environment. A 10-question survey was conducted to review the effects of welding hazards on the human body, carcinogenicity information, international (US, UK, France) exposure standards, general characteristics between the two groups, and awareness of occupational health. Results: Exposure to hazardous factors in both groups was below the standards set by MOEL. Specialized high school students were exposed to higher levels than workers, and some hazardous factors exceeded the standards when compared to international exposure standards. During the survey, students were less aware of the hazards of welding, safety and health education, and the need for work environment measurement than workers. Conclusions: For the respiratory protection of students in vocational high school welding labs, it is necessary to create a comfortable training environment. Exposure standards for harmful factors should be strictly applied, such as overseas standards, or exposure should be limited by setting a limit on the number of hours of welding practice per week. In addition, it is necessary to conduct safety and health education for welding students to raise their awareness of the importance of measuring the working environment and wearing appropriate protective equipment.

• Korean Journal of Optics and Photonics
• /
• v.9 no.5
• /
• pp.315-320
• /
• 1998

The characteristics and structures of photopolymer are analyzed in this paper, which recently have various applications in optical information processing and optical memory, Especially, Du Pont's photopolymer OmniDex 706 reflection film is used in many experiments of different exposures and incident angles, and analyzed by the diffraction pattern generated by glass plate's reflection beam. With the dark reaction of the monomer in photopolymerization, dynamic parameters are considered due to the variation of exposure time and diffusion time delay after exposure. The performance of diffraction efficiency is improved by 10%, when an exposure time is 6.25 sec, and a diffusion time delay is 2 minute.

• Transactions on Electrical and Electronic Materials
• /
• v.1 no.3
• /
• pp.10-13
• /
• 2000

In this study the new photo-alignment material copoly(PM4Ch-ChMa)(copoly (poly (4-methancryloyloxy)chalcone-cholesteryl methacry late)) was synthesized, Also, the liquid crystal (LC) aligning capabilities and the electro-optical(EO) characteristics for the photo-aligned vertical-aligned(VA)-LC display(LCD) were studied. The monodomain alignment of the NLC for the photo-aligned VA-LCD by linearly polarized UB exposure on the Photo-dimerized copoly(PM4Ch-ChMA) surface was observed,. Excellent Voltage-transmittance characteristics for the VA-LCD photo-aligned by polarized UV exposure on the copoly (PM4Ch-ChMA) surfaces for 1 min was achieved. The response time of the VA-LCD photo-aligned by polarized UV exposure on the copoly (PM4Ch-ChMA) surfaces for 1 min was 39.3 ms, We suggest that the photo-dimerized chacone group increased with increasing UV exposure time, which then contributes to a low response time of the photo-aligned VA-LCD on the copoly (PM4Ch-ChMA) surfaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.04a
• /
• pp.89-90
• /
• 2006

Electro-optical (EO) characteristics of in-plane switching (IPS) cell on the polyimide surface using obliquely ion beam (IB) exposure as new ion beam (IB) type system (DuoPIGatrion ion source). A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the polyimide surface was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned IPS-cell on poly imide surface ; the stable VT curve in the ion-beam-aligned IPS cell on a poly imide (PI) surface with ion beam exposure using new type IB equipment was obtained. and the fast response time in the ion-beam-aligned IPS cell on a polyimide (PI) surface with ion beam exposure using new type IB equipment was obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.432-433
• /
• 2006

Electro-optical (EO) characteristics of twisted nematic (TN) - liquid crystal display (LCD) on the NDLC thin film using obliquely ion beam (IB) exposure as new ion beam (IB) type system (DuoPIGatrion ion source). A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the NDLC thin film was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-cell on polyimide surface ; the stable VT curve in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained. and the fast response time in the ion-beam-aligned TN cell on the NDLC thin film with ion beam exposure using new type IB equipment was obtained.