• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.302-307
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• 2017

Draft ice in polar regions is formed due to sea level changes and various environmental factors cause damage due to collision with offshore plants and ships for resource development. Drift ice in polar regions is a potential source of accidents for offshore plants that perform long-term operations in one place, as well as on the ship. To prevent accidents with drift ice, offshore plants and ships in polar regions use satellite image information and detection radar to detect drift ice. However, the inability to use visible satellite images at night significantly lowers the detection probability by radar for small drift ice. In this study, we used a thermal imaging system which can be operated day and night for the detection of drift ice, and carried out an experimental study on the detection characteristics of drift ice. To examine the night operation of the thermal imaging system, the experimental condition was set and the thermal image was measured according to the measurement angle change. Under this condition, the correlation was analyzed by theoretical calculating the radiant energy of the drift ice and the sea water.

• Journal of Environmental Science International
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• v.22 no.8
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• pp.1053-1062
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• 2013

The shortwave aerosol direct radiative forcing (SWARF) was analyzed using the Clouds and Earth's Radiant Energy System (CERES) data in the East Asian region from 2001 to 2010. In the Yellow Sea and the Korean Peninsula, located in the leeward side of China, significantly negative high SWARF at the top of atmosphere (TOA) occurs due to the long-range transport of anthropogenic (e.g. sulphate) and natural aerosols (e.g. mineral dust) from the East Asian continent. Conversely, eastern China has much higher levels of SWARF at the surface (SFC) due to anthropogenically emitted aerosol than in the Yellow Sea and the Korean Peninsula. Since the radiative forcing of aerosols in the atmosphere are different in type, aerosol types were classified into sea salt+sulphate, smoke, sulphate and dust by using satellite data. The analysis on the SWARF by the classified aerosol types indicated that sulphate occupies a predominant portion of the atmosphere in the Yellow Sea and the Korean Peninsula in the summer. In particular, the annual averages of the summer TOA SWARF increased in the Yellow Sea and the Korean Peninsula from 2001 to 2010.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1557-1566
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• 2004

A flame extinction phenomenon is a typical unsteady process in combustion. Flame extinction is characterized by various physical phenomena, such as convection, diffusion, and the production of heat and mass. Flame extinction can be achieved by either increasing the strain rate or curvature, by diluting an inert gas or inhibitor, or by increasing the thermal or radiant energy loss. Though the extinction is an inherently transient process, steady and quasi-steady approaches have been used as useful tools for understanding the flame extinction phenomenon. Recently, unsteady characteristics of flames have been studied by many researchers, and various attempts have been made to understand unsteady flame behavior, by using various extinction processes. Representative parameters for describing flame, such as flame temperature, important species related to reactions, and chemi-luminescence of the flame have been used as criterions of flame extinction. In these works, verification of each parameter and establishing the proper criterions of the extinction has been very important. In this study, a time-dependent flame temperature and an OH radical concentration were measured using optical methods, and the instantaneous change of the flame luminosity was also measured using a high-speed ICCD (HICCD) camera. We compare the unsteady extinction points obtained by three different methods, and we discuss transient characteristics of maximum flame temperature and OH radical distribution near the extinction limit.

• Journal of Biosystems Engineering
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• v.31 no.3 s.116
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• pp.168-174
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• 2006

The purpose of this study is to develop the cold chain system by developing optimal phase change materials (PCM). There are some benefits from developing this system such as keeping freshness of agriculture products, saving energy, etc. The major results are as follows. To decide a latent heat material, the characteristics of water, sodium, polyacrylate, ethanol and N-tetradecane are analysed. Also, an insulating material is made by mixing water, nucleating agent and latent heat material, using cementing method. In addition, the sensitivity analysis for developed latent heat material($K_l,\;K_2,\;K_3$) is conducted. For $K_l,\;K_2,\;K_3$ which cans keep latent heat temperature, ranging from $0\;to\;5^{\circ}C,\;5\;to\;10^{\circ}C,\;10\;to\;15^{\circ}C$. it can keeps latent heat temperature at radiant heat (5, 12, $17^{\circ}C$) and transportation latent heat container both melting temperature and amount of latent heat of Kl are $-1.6{\pm}1.0^{\circ}C$, 326.51 J/g, respectively and freezing temperature and latent heat are $-7.98{\pm}1.5^{\circ}C$ and 174.18 J/g. and $K_2$ are $7.41{\pm}1.5^{\circ}C$, 89.80 J/g, respectively and freezing temperature and latent heat are $-2.14{\pm}1.5^{\circ}C$ and 83.90 J/g. and $K_3$ are $9.54{\pm}1.0^{\circ}C$, 145.42 J/g, respectively and freezing temperature and latent heat are $0.21{\pm}1.0^{\circ}C$ and 152.48 J/g.

• 보존과학연구
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• s.17
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• pp.123-160
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• 1996

There have been many studies and experiments regarding exhibition lighting. Many experiments on photochemical damaging effect and visibility resulted in a practice limited to assigning light levels and adjusting annual exposure time. The three damaging factors to the artifacts are intrinsicsusceptibility to absorb radiant energy, spectral distribution of light source and intensity of illumination and time of exposure. Dividing all the artfacts into three categories to suggest a recommended illuminance level causes some problems. Blue wool, for example, used as the reference material for susceptibility, is not a standard material representing museum artifacts. In the most light sensitive category, ISO class I or anything below have been excluded. The exposure time of one soure can be three times more than another sourece. The spectral distribution of the light source and the relative spectral responsibility of the artifact are not considered in the practice. So in case of very light sensitive material, the recommended illuminance is only the referring value and it is indispensable to check the characteristic of susceptibility of each artifacts. Daylighting is prevailing method to solve the psychological need of the visitors. However, it sould transparent, and should not diffused, and the green-house effect must be considered. llluminance uniformity should based on the maximum illuminance to handle the limitation of exposure for the conservation of a large sensitive object such as a painting. Damage index is not absolute reference for selecting the lighting source because it is experimented from the paper of low grade then calculated. Visibility should be increased by reducing the visual noiseand by planning of appropriate luminance contrast. This paper reviews the problems with the previous studies and experiment sand the current exhibition lighting design practice. The plan for museum showcase lighting is to check the susceptibility and to raise the visibility simultaneously.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.28.4-29
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• 2009

The 'Amon-Ra' instrument of the proposed 'EARTHSHINE' satellite is a dual (i.e. imaging and energy) channel instrument for monitoring the total solar irradiance (TSI) and the Earth's irradiance at around the L1 halo orbit. Earlier studies for this instrument include, but not limited to, design and construction of breadboard Amon-Ra imaging channel, stray light suppression and system performance computation using Integrated Ray Tracing (IRT) technique. The Amon-Ra instrument is required to produce 0.3% in uncertainty for both Sunlight and Earthlight measurement. In this study, we report accurate estimation of the output electric signal derived from the orbital variation of radiant exitance from the Sun and the Earth arriving at the aperture and detector plane of the Amon-Ra. For this, orbital irradiance are computed analytically first and then confirmed by simulation using Integrated Ray Tracing (IRT) model. Specially, the results show the arriving power at the bolometer detector surface is $1.24{\mu}W$ for the Sunlight and $1.28{\mu}W$ for the Earthlight, producing the output signal pulses of 34.31 mV and 35.47 mV respectively. These results demonstrate successfully that the arriving radiative power is well within the bolometer detector dynamic range and, therefore, the proposed detector can be used for the in-orbit measurement sequence. We discuss the computational details and implications as well as the simulation results.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.6 no.1
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• pp.179-213
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• 1984

The history of recording and conserving for maintenance the human's memory from ancient times to modern's has brought about a lot of changing process of the recorded information media with developing in culture, and each society has made important recorded materials in his library as essentially the social apparatus. But most of them that were damaged by factors of the natural disaster, humidity, temperature, light, fungi and insects in the library, and were resulted in deterioration and losing the numerous materials. For removing the inevitable phases repeated, there are studying for counterplan of the fundamental environment factors about preservation, restoration and chemical research of materials in advanced countries, but I get a few researches about protecting the cultural properties. Therefore I research the survey of the actual conditions on 72 university libraries centering around them, and then I have researched the collection rate 81 percent, 58 university libraries. (local : 35, in seoul : 23) As the result of this research, I propose the model of the environment factors of conserving the library materials. 1) To apply the equipment of processing the radiant energy to the new construction and buildings. 2) To remove factors that occur fungi and insects by facilities being controlled relative humility, temperature, and to equip the ventilation arrangement in the library. 3) To shelve all acquired and bound materials after proceeding the vacuum fumigator. 4) Those who want to enter into the library stack were surely taken in sterilzing their hands and shoes, and must put on the gown. 5) To use the vacuum dusting thing (machine) for removing the dust without spreading out the floor of the library at any time. 6) To set up the gas automatic fire extinguisher worked by smoke sensor. 7) To assist the research into the preservation, natures and environment of recorded materials, and to supply financial funds for librarian. 8) To hold regularly the workshop be able to educate the methods of preservation materials by the constant system. (Library Association) 9) To add to responsibilities on certification of preservation materials for librarian. 10) To hold the constant committee system in each library. 11) To keep up with the ideal environment (humidity, temperature, light, ventilation, etc.) of preservation materials in the arrangement room, and to put on the gown.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.414-421
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• 2023

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanate-based glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb₂O₃ were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb₂O₃ was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 ℃, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1275-1288
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• 2015

A microscale weather analysis module (about 1km or less) is a microscale numerical weather prediction model designed for operational forecasting and atmospheric research needs such as radiant energy, thermal energy, and humidity. The accuracy of the module is directly related to the usefulness and quality of real-time microscale weather information service in the metropolitan area. This paper suggests an object based verification method useful for spatio-temporal evaluation of the accuracy of the microscale weather analysis module. The method is a graphical method comprised of three steps that constructs a lattice field of evaluation statistics, merges and identifies objects, and evaluates the accuracy of the module. We develop lattice fields using various evaluation spatio-temporal statistics as well as an efficient object identification algorithm that conducts convolution, masking, and merging operations to the lattice fields. A real data application demonstrates the utility of the verification method.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.94-101
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• 2009

This study which is the fundamental work to investigate the property of urban climate compared the property of thermal environment in the downtown location and the outskirt site based on the field observation in the summer. We analysed thermal environment in the downtown location mainly by distributional characteristics during day and night with changes and correlation analysis of the air temperature, the globe temperature and the surface temperature through the simultaneous observation of the property of thermal environment at two places in real time. The summary of finding in this study is as follows. (1)It is observed on the day chosen by sample that diurnal air temperature range in the downtown location is $22.3{\sim}34.9^{\circ}C$, and diurnal air temperature range in the Outskirt site is $20.0{\sim}34.3^{\circ}C$, so, we found that the diurnal air temperature range in the outskirt site is $1.7^{\circ}C$ higher than in the downtown location. (2)In comparison of the globe temperature after sunset, we found the change of more sudden temperature drops in the outskirt site than in the downtown location. (3)It is observed on the days chosen by sample that the average of globe temperature range is $1.1^{\circ}C$, the average of surface temperature range is $1.0^{\circ}C$, and air temperature range is $2.0^{\circ}C$, thus, the we found that the average of air temperature is $1.0^{\circ}C$ higher than globe temperature and the surface temperature. (4)After the consideration of air temperature and globe temperature distribution, the highest temperature reaching time of globe temperature is one hour earlier than air temperature in the downtown location, on the other hand, although the highest temperature reaching time of globe temperature in the outskirt sites is one hour later than in the downtown location, the timelag found in the downtown location was not found in the outskirt site.