• Geomechanics and Engineering
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• 제32권6호
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• pp.627-637
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• 2023

Volleyball is an international sport with many fans. This sport has made significant progress in schools and clubs. Volleyball is suitable for all age groups and can be used in different environments. It has many social and physical benefits. During the game provides special physical training for the players and is considered one of the most exciting games. Another type of volleyball is beach volleyball, a beach sport and one of the Olympic sports held on the sand with the same rules as volleyball. This sport is usually played in coastal areas, especially with wide sandy beaches. Because this sport is played in open spaces, the players stay in this space for a long time and are exposed to dangerous ultraviolet radiation. It is a wavelength of light in the range of electromagnetic waves with a wavelength between 10 and 400 nm. This wavelength is shorter than visible light and more protracted than X-ray. Ultraviolet (UV) rays are naturally present in sunlight and include about 10% of all waves emitted from the sun's surface. Prolonged exposure to ultraviolet light causes acute and chronic damage to the skin and vision and even destroys the entire immune system. Different covers of the earth's surface reflect different amounts of UV rays. For example, snow cover, sand, and seawater surface reflect this radiation. Therefore, the health of volleyball players is in danger due to this harmful radiation. This work aims to introduce a type of clothing made of nanoparticles that can repel ultraviolet rays and protect beach volleyball players whose health is at risk from this radiation.

• 한국태양에너지학회 논문집
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• 제28권5호
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• pp.14-20
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• 2008

As the number of buildings that use the transparent permeation materials as the outer wall is on the increase, the coming amount of the light rays is a lot, and thus the increase in the cooling load and the radiant heat of high temperature may cause the residents to discomfort. In order to reduce such influences, this paper analyzed the installation effects of the sunshade BIPV. The inner temperature of the room installed the sunshade BIPV or otherwise was measured, and compared and analyzed the effects of reducing the cooling load by the incoming light rays. The sample space of the third floor of S university installed the sunshade BIPV has two rooms on the same conditions, and for five sunny days selected in August, the researcher measured the air temperature and the temperature of the fittings with closing the windows to minimize the movement of air without operating the coolers. The maximum cooling load measured by the incoming light rays in the room where the sunshade BIPV was not installed was examined as 459.13kcal/h. It can be understood as the effect of reducing the cooling load according to the incoming rays of the room with sunshade BIPV. Even though the effect of cooling load reduction is not so great in a room, the total reduction in cooling room for the 32 rooms installed the sunshade BIPV was estimated to be 40442.27kcal/day, which will be able to bring the maximum reduction effect of 17.1kW in energy and reduce the investment cost owing to the reduction in cooling load when initially designing the building.

• 한국표면공학회지
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• 제56권4호
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• pp.233-242
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• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• 융합정보논문지
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• 제8권1호
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• pp.147-152
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• 2018

자외선 완전차단 및 청색광을 일부 차단하고 광변색성을 가지는 편광안경렌즈를 개발하였다. 심야 운전이나 반사광에 의한 눈부심을 획기적으로 줄이고 자외선이 강한 공간에서는 선글라스 역할을 하며 평상시는 안경렌즈로 사용할 수 있는 기능성 안경렌즈이다. 광변색성은 명반응에서는 0.5초 암반응에서는 3초 정도의 회복시간이 걸렸다. 편광기능은 95% 정도를 얻었다. 자외선은 완전히 차단되었고 청색광은 30%정도의 저감 효과를 얻었다. 광변색성 및 자외선차단기능과 편광기능을 하나로 결합한 렌즈는 국내 시장을 조사한 결과 최초의 시도이다.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.72-80
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• 2017

Gamma-ray has some advantages as a weapon: it has the ability to transmutate matter, high penetrability through materials, and it is very harmful to living things. So it is worth to study the features of gamma-ray weapon in order to utilize it. Such abilities were simulated on the basis of Monte Carlo simulation program GEANT4. For the simulation conceptual design of gamma-ray weapon was conducted. High energy electrons, which were necessary for the high energy gamma-rays, were produced by linear electron accelerator, of which the parameters were derived from the Pohang Light Source(PLS-II). Gamma-rays were get by bremsstrahlung mechanism. The spectra of gamma-rays, that were measured at distances of 500 m, 1000 m, 1500 m and 2000 m, were gained by GEANT4.

• 복식문화학회:학술대회논문집
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• 복식문화학회 2000년도 International Costume Culture Conference (한글판)
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• pp.33-35
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• 2000

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1412-1414
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• 2009

It is suggested that the light extraction efficiency of the display device can be improved by adoption of periodic array of sub-wavelength scale structures. The relief of the total reflection has been investigated using the rigorous coupled wave analysis (RCWA). Various shape of the sub-wavelength scale structure allowed to have non vanishing transmittance for the light rays with the incident angle bigger than the critical angle.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.123-125
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• 2002

Blue light of Cherenkov radiation generated by electrons in transparent substances such as water and acrylic resin is well known generally. If students can easily observe the blue light at school, they may be impressed by the fascinating radiation. Four years ago, management of the Co-60 unit for radiotherapy was transferred to Nagoya University School of Health Sciences from a related hospital. We have examined whether or not the Cherenkov radiation in water from secondary electrons generated by Co-60 gamma-rays can be safely observed by eyes and photographs. First, the Cherenkov radiation in the water tank was led to the corridor outside the irradiation room by a mirror, and observed directly without any effect of the radiation exposure. Second, photographs of the Cherenkov radiation were taken under the conditions consisted of several irradiation fields and pass lengths of gamma-rays in water.

• 천문학회보
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• 제42권2호
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• pp.67.3-68
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• 2017

Bright rays are often observed after coronal mass ejections (CMEs) erupt. These rays are dynamical structures along which plasmas move outward. We investigated the outflows along the post-CME rays observed by the COR2 on board STEREO Behind on 2013 September 21 and 22. We tracked two CMEs, two ray tips, and seven blobs using the NAVE optical flow technique. As a result, we found that the departure times of blobs and ray tips from the optimally chosen starting height of 0.5 $R{\odot}$ coincided with the occurrence times of the corresponding recurrent small flares within 10 minutes. These small flares took place many hours after the major flares. This result supports a magnetic reconnection origin of the outward flows along the post-CME ray and the importance of magnetic islands for understanding the process of magnetic reconnection. The total energy of magnetic reconnection maintaining the outflows for 40 hr is estimated at 1.4' 1030 erg. Further investigations of plasma outflows along post-CME rays will shed much light on the physical properties of magnetic reconnection occurring in the solar corona.

• 한국미생물·생명공학회지
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• 제33권3호
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• pp.222-225
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• 2005

Stimulatory effects of near infra-red (NIR) rays radiation have been studied within the limits of photosynthesis, phototaxis, and photodermatology. While most of these studies have been done by direct NIR radiation, we investigated the effects of the NIR rays-treated materials on microbial growth. NIR in wavelength of 1,400${\~}$1,700 nm was applied for different kind of materials. Under fast growing conditions in rich media, materials treated with the NIR rays or not did not show any differences in growth of microorganisms. However, under slow growing conditions in minimal media, data showed that NIR rays-treated cloths and hygienic bands affect negatively on the growth of bacteria (Salmonella enteritidis) and fungi (Candida albicans). In addition, it was estimated that the effect of NIR rays on bacterial growth is kept going on S. enteritidis.