Surface morphology and optical properties such as transmittance and haze effect of glass etched by physical and chemical etching processes were investigated. The physical etching process was carried out by pen type sandblasting process with 15~20 μm dia. of Al2O3 media; the chemical etching process was conducted using HF-based mixed etchant. Sandblasting was performed in terms of variables such as the distance of 8 cm between the gun nozzle and the glass substrate, the fixed air pressure of 0.5bar, and the constant speed control of the specimen stage. The chemical etching process was conducted with mixed etching solution prepared by combination of BHF (Buffered Hydrofluoric Acid), HCl, and distilled water. The morphology of the glass surface after sandblasting process displayed sharp collision vestiges with nonuniform shapes that could initiate fractures. The haze values of the sandblasted glass were quantitatively acceptable. However, based on visual observation, the desirable Anti-Glare effect was not achieved. On the other hand, irregularly shaped and sharp vestiges transformed into enlarged and smooth micro-spherical craters with the subsequent chemical etching process. The curvature of the spherical crater increased distinctly by 60 minutes and decreased gradually with increasing etching time. Further, the spherical craters with reduced curvature were uniformly distributed over the etched glass surface. The haze value increased sharply up to 55 % and the transmittance decreased by 90 % at 60 minutes of etching time. The ideal haze value range of 3~7 % and transmittance value range of above 90 % were achieved in the period of 240 to 720 minutes of etching time for the selected concentration of the chemical etchant.

Oxide layers were formed by an environmentally friendly plasma electrolytic oxidation (PEO) process on AZ91 Mg alloy. PEO treatment also resulted in strong adhesion between the oxide layer and the substrate. The influence of the KF electrolytic solution and the structure, composition, microstructure, and micro-hardness properties of the oxide layer were investigated. It was found that the addition of KF instead of KOH to the Na2SiO3 electrolytic solution increased the electrical conductivity. The oxide layers were mainly composed of MgO and Mg2SiO4 phases. The oxide layers exhibited solidification particles and pancake-shaped oxide melting. The pore size and surface roughness of the oxide layer decreased considerably with an increase in the concentration of KF, while densification of the oxide layers increased. It is shown that the addition of KF to the basis electrolyte resulted in fabricating of an oxide layer with higher surface hardness and smoother surface roughness on Mg alloys by the PEO process. The uniform thickness of the oxide layer formed on the Mg alloy substrates was largely determined by the electrolytic solution with KF, which suggests that the composition of the electrolytic solution is one of the key factors controlling the uniform thickness of the oxide layer.

ZnS powder was synthesized using a relatively facile and convenient glycothermal method at various reaction temperatures. ZnS was successfully synthesized at temperatures as low as 125 oC using zinc acetate and thiourea as raw materials, and diethylene glycol as the solvent. No mineralizers or precipitation processes were used in the fabrication, which suggests that the spherical ZnS powders were directly prepared in the glycothermal method. The phase composition, morphology, and optical properties of the prepared ZnS powders were characterized using XRD, FE-SEM, and UV-vis measurements. The prepared ZnS powders had a zinc blende structure and showed average primary particles with diameters of approximately 20~30 nm, calculated from the XRD peak width. All of the powders consisted of aggregated secondary powders with spherical morphology and a size of approximately 0.1~0.5 μm; these powders contained many small primary nanopowders. The as-prepared ZnS exhibited strong photo absorption in the UV region, and a red-shift in the optical absorption spectra due to the improvement in powder size and crystallinity with increasing reaction temperature. The effects of the reaction temperature on the photocatalytic properties of the ZnS powders were investigated. The photocatalytic properties of the assynthesized ZnS powders were evaluated according to the removal degree of methyl orange (MO) under UV irradiation (λ = 365 nm). It was found that the ZnS powder prepared at above 175 oC exhibited the highest photocatalytic degradation, with nearly 95 % of MO decomposed through the mediation of photo-generated hydroxyl radicals after irradiation for 60 min. These results suggest that the ZnS powders could potentially be applicable as photocatalysts for the efficient degradation of organic pollutants.

In the present study, domain evolution processes of a near-morphotropic PZT ceramic during poling was studied using vertical piezoresponse force microscopy (PFM). To perform macroscopic poling in bulk polycrystalline PZT, poling was carried out in a stepwise fashion, and PFM scan was performed after unloading the electric field. To identify the crystallographic orientation and planes for the observed non-180o domain walls in the PFM images, compatibility theory and electron backscatter diffraction (EBSD) were used in conjunction with PFM. Accurate registration between PFM and the EBSD image quality map was carried out by mapping several grains on the sample surface. A herringbone-like domain pattern consisting of two sets of lamellae was observed; this structure evolved into a single set of lamellae during the stepwise poling process. The mechanism underlying the observed domain evolution process was interpreted as showing that the growth of lamellae is determined by the potential energy associated with polarization and an externally applied electric field.

This present study deals with the microstructure and tensile properties of 600 MPa-grade high strength and seismic resistant reinforcing steels. The high strength reinforcing steel (SD 600) was fabricated by Tempcore processing, while the seismic resistant reinforcing steel (SD 600S) was air-cooled after hot-rolling treatment. The microstructure analysis results showed that the SD 600 steel specimen consisted of a tempered martensite and ferrite-pearlite structure after Tempcore processing, while the SD 600S steel specimen had a fully ferrite-pearlite structure. The room-temperature tensile test results indicate that, because of the enhanced solid solution and precipitation strengthening caused by relatively higher contents of C, Mn, Si and V in the SD 600S steel specimen, this specimen, with fully ferrite-pearlite structure, had yield and tensile strengths higher than those of the SD 600 specimen. On the other hand, the hardness of the SD 600 and SD 600S steel specimens changed in different ways according to location, dependent on the microstructure, ferrite grain size, and volume fraction.

In order to improve the high temperature oxidation resistance and lifespan of mat type porous carbon insulation, SiC was coated on carbon insulation by solution coating using polycarbosilane solution, curing in an oxidizing atmosphere at 200 oC, and pyrolysis at temperatures up to 1200 oC. The SiOC phase formed during the pyrolysis process was converted into SiC crystals as the heat treatment temperature increased, and a SiC coating with a thickness of 10-15 nm was formed at 1600 oC. The SiC coated specimen showed a weight reduction of 8.6 % when it was kept in an atmospheric environment of 700 oC for 1 hour. On the other hand, the thermal conductivity was 0.17W/mK, and no difference between states before and after coating was observed at all.

With the matters of climate change, energy security and resource depletion, a growing pressure exists to search for replacements for fossil fuels. Among various sustainable energy sources, hydrogen is thought of as a clean energy, and thus efficient hydrogen storage is a major issue. In order to realize efficient and safe hydrogen storage, various porous materials are being explored as solid-states materials for hydrogen storage. For those purposes, it is a prerequisite to characterize a material’s textural properties to evaluate its hydrogen storage performance. In general, the textural properties of porous materials are analyzed by the Brunauer-Emmett-Teller (BET) measurement using nitrogen gas as a probe molecule. However, nitrogen BET analysis is sometimes not suitable for materials possessing small pores and surfaces with high curvatures like MOFs because the nitrogen molecule may sometimes be too large to reach the entire porous framework, resulting in an erroneous value. Hence, a smaller probe molecule for BET measurements (such as hydrogen) may be required. In this study, we describe a cost-effective novel cryostat for BET measurement that can reach temperatures below the liquefaction of hydrogen gas. Temperature and cold volume of the cryostat are corrected, and all measurements are validated using a commercial device. In this way, direct observation of the hydrogen adsorption properties is possible, which can translate directly into the determination of textural properties.

Nano-sized Zinc selenide (ZnSe) powder was successfully synthesized using Zn and Se precursors in a hydrothermal process. Temperature for the synthesis was varied from 95 oC to 180 oC to evaluate its influence on the microstructural properties of the synthetic particles. ZnSe powder thus fabricated was characterized using various analytical tools such as SEM, XRD, TEM and UV-Vis methods. Two types of ZnSe particles, that is, the precipitated particle and the colloidal particles, were identified in the analysis. The precipitated particles were around 100 nm in average size, whereas the average size of the colloidal particles was around 20 nm. The precipitated particles made at 150 oC and 180 oC were found to be a single phase of ZnSe; however, an inhomogeneous phase was obtained at the lower synthesis temperature of 95 oC, suggesting that the temperature for the synthesis should be over 100 oC. The precipitated particles were inactive in the UV-Vis absorption investigation, whereas the colloidal particles showed that absorptions occurred at 380 nm in the UV-Vis spectrum.

To gather information on the indoor air quality of the greenhouses used for edible oakwood mushroom cultivation, temperature, humidity, and bacterial concentration and species were investigated in 2015 and 2016 in 21 mushroom greenhouses located in ten different regions in Korea. Temperature and humidity of all the mushroom greenhouses ranged from 16.2 to 30.8°C and from 28.2 to 85.6%, respectively. Bacterial concentration exceeded the Korean indoor air quality standard value (800 cfu/m3) in 15 of the 21 mushroom greenhouses. A total of 33 genera and 76 species were identified in the indoor air of the mushroom greenhouses investigated. Of the identified bacteria, 10 genera and 15 species including Acidovorax oryzae, Bacillus infantis, B. licheniformis, Cellulosimicrobium funkei, Ewingella Americana, Exiguobacterium sibiricum, Leclercia adecarboxylata, Lysinibacillus sphaericus, Pseudomonas fulva, Raoultella terrigena, Staphylococcus cohnii, S. haemolyticus, S. saprophyticus, S. sciuri, and Streptomyces sindenensis are among those known to have a harmful effect on human health. These bacteria have been reported to cause sepsis, skin infection, bloodstream infection, bacteremia, spondylitis, peritonitis, acute meningitis, endocarditis and urinary tract infection. The results of this study indicate that continuous hygiene management of indoor air is necessary in the greenhouses used for oakwood mushroom cultivation.

The objectives of this study were to investigate the effects of PM10 and O3 concentration on the symptoms of allergic diseases. The questionnaire was used to determine whether or not symptoms of allergic diseases were present from September to October 2012. The air pollution concentration data used was the corresponding point CEM (continuous emission monitoring) data. The average concentration of PM10 was 56.09 μg/m3 in the control area, and the concentration in the exposed area was 40.44 μg/m3. In the two areas, concentration of O3 was 28.73 ppb and 28.74 ppb, respectively. The total average concentrations of PM10 and O3 were 45.66 μg/m3 and 28.73 ppb in the Gwangyang area. The rate of asthma diagnosis was higher in the control area (9.6%) than in the exposed area (4.1%), but the rate of allergy eye disease was higher in the exposed area (23.9%) than in the control area (16.5%). There was a significant difference in the symptoms of some allergic diseases when the relative concentration of PM10 and O3 were high and low.

During the decay process of food waste, odor and leachate are generally produced because food is easily decomposed due to its high organic and moisture contents. In this study, various food waste samples, including samples artificially prepared and collected from actual waste containers, were tested to determine odor and leachate production as the samples were decomposed at a constant temperature of 35°C. In the air phase, total volatile organic compounds (TVOCs), acetaldehyde (AA), methyl mercaptan (MM), hydrogen sulfide (H2S), and dimethyl sulfide (DMS) were measured as a function of the decay period for four days. The results of the experiment showed that TVOC and AA were produced at higher concentrations in the actual food waste than in all artificial wastes. The AA concentration accounted for about 90% of the TVOC in all of the waste samples except for the food waste containing meat and fish only. The concentrations of volatile sulfur compounds (VSCs) were generally lower than 100 μg/kg, and the concentration of DMS was the highest among the VSCs. In the waste sample containing meat and fish only; however, the concentration of VSCs increased up to 1,700 μg/kg, and mostly consisted of MM and DMS. Complex odor concentrations were found to be the highest after a decay period of 12-48 hours. In addition, the complex odor was mostly related to VSCs with low odor thresholds rather than the TVOC. The pH values mostly decreased from 5 to 3.5 as the waste samples were in the decomposition periods, while the pH value increased to 6 in the food waste containing meat and fish only. Consequently, odor intensity and leachate production were the highest in the 12-48 hour range as the decomposition started, and thus an appropriate control strategy needs to be implemented based on the waste composition and the decay period.

The aim of this study was to examine indoor fungal concentration and fungal volatile organic compounds(VOCs) in single-person households. A total of 22 houses occupied by one person were investigated in this study. 19 VOCs detected in the field were estimated as fungi-derived VOCs through a review of the literature, and 11 VOCs were confirmed as fungal VOCs by laboratory experiments. Exposure to fungal VOCs in the indoor environment has been confirmed to be highly influenced by airborne fungal concentration and indoor humidity. 3-octanone was characterized by a clear generation profile in Aspergilus versiocolor, and n-decane in Pencillum chrysogenum. ntetradecane emitted by Stachybotrys chartarum exhibited a tendency to occur consistently. The observations made in this study demonstrated that single-person households can easily be exposed to fungi, and MVOCs can be used as an indicator of fungal exposure in indoor environments.

The most effective microbial strains with the best ability to reduce complex odor were isolated from earthworm and activated sludge and identified using a 16S rDNA method. The isolated strains, Staphylococcus cohnii HYC-3 and S. carnosus JYC-4, were inoculated into the odor vials that had been left for 48 hours in water containing sesame dregs, and after 3 days, the ammonia was reduced to 5 ppm and 3 ppm from the initial 25 ppm, respectively. Complex odor was reduced to 2.5 and 2.2, respectively, while the control group maintained an odor of 5. The isolates were grown in the order of 30°C > 40°C > 20°C > 10°C. For HYC-3 and JYC-4, the optimum pH was 7 and 10, respectively, and the strains grew well at neutral pH ranges. To monitor the amount of microorganisms remaining in the environment by using the strain as a preparation for odor reduction, a probe for real-time PCR was designed. Through the quantitative and sensitivity tests on the developed strains, it was found that they showed excellent sensitivity.

Despite increasing public concern following mass media coverage regarding the risk of radon to human health and the need to control it, there remains a lack of infrastructure for measuring and mitigating radon. Against this backdrop, this paper is part of an effort to formulate an environment-management framework that can help resolve environmental issues relating to radon, ease fears regarding the associated risks, and provide radon-specific quality services. This study aimed to suggest locally applicable measures for training experts specializing in the fields of measuring and mitigating radon mainly based on US cases in which radon measurement and mitigation certification programs have been systematically run and supervised. Given the lack of both awareness on radon and experts in Korean circumstances, it is necessary to come up with a scheme to develop a radon-specific education program and a framework for expert accreditation. Thus, as groundwork for their introduction considering local circumstances, top-down measures led by the relevant department of government-led organizations, which will act as the control tower, should first be implemented to best utilize the insufficient human resources in this area. In addition, more systematic and detailed educational programs and an expert certification system need to be developed in accordance with the established foundations, and to support their consistent operation, a relevant administrative system should be constructed.

Exposure to the indoor air pollutants could be associated with the risk of developing atopic dermatitis, including allergic symptoms and exacerbations. A total of Fifty homes who had a past or current symptoms of atopic dermatitis were enrolled in the study. To rate the levels of environmental factor, we measured concentrations of PM2.5, PM10, Heavy metals XRF (X-Ray Fluorescene), Bacteria (CFU/m3), mold (CFU/m3) in dust of the children’s houses. The prevalence of atopic dermatitis in children is increasing especially in Urban areas. Exposure to levels of indoor environmental factor and air pollutants has been related to atopic dermatitis development. The house dust were higher for the results of atopy, asthma patients analyzed fungi and bacteria, resulting XRF measurements Cr (chromium), As (arsenic), Br (bromine), Cd (cadmium), Hg (mercury), Pb (lead) etc. this has a significant relationship. Recent studies have shown that indoor air pollutants control is beneficial in reducing atopic dermatitis prevalence and development. Urban areas children are exposed to kinds of indoor environmental factor and air pollutants that may lead to atopic dermatitis development.

In this study, the behavior of dominant microbial communities was investigated in the treatment of porcine carcasses using an anaerobic high temperature burial composting method. The correlation between odor emission and bacterial community structure was analyzed through principal component analysis and extended local similarity analysis. In the burial layer of porcine carcass, the dominant bacteria were Bacillaceae (46%), Thermoactinomycetaceae (15%) and Lactobacillaceae (4%) in the early stage and Bacillaceae (46%), Thermoactinomycetaceae (15%), Lactobacillaceae (4%) in the end. Clostridiaceae (CH3SH), Bacillacea ((CH3)2S2), Clostridium ((CH3)2S2), Clostridial (H2S), Oceanobacillus (H2S), and Thermoanaerobacteraceae (H2S) were closely related to the sulfurous odorants, which are the highest odor contributions. The emission of sulfurous odor substances such as H2S, CH3SH, (CH3)2S, and (CH3)2S2 showed a positive correlation with each other, but showed a negative correlation with nitrogenous odorants (NH3 and TMA), aldehydes, organic acids, and VOCs. The results of this correlation analysis can provide useful information that enables us to understand the characteristics of microbial communities and odor generation during the degradation of carcasses and to manage odors and burial sites in the treatment of carcass.

이 논문은 통신비밀보호법상 통신사실확인자료와 전기통신사업법상 통 신자료의 제공을 포괄하는 이른바 “통신비밀자료”의 제공과 관련하여 미 국, 영국, 독일, 일본 등 주요외국의 법제와 우리의 개인정보보호법을 비 교법적 관점에서 검토하여 관련법령의 개선방향을 제시한다. 주요외국의 통신비밀자료에 대한 활용 및 보호의 정도가 모두 일치하는 것은 아니지 만 그 대체적인 추세와 비교하더라도 우리의 통신비밀보호법제의 현저하 게 드러나는 문제점은 발견되지 않았다. 다만, 전기통신사업법상의 통신 자료가 개인정보에 해당하기 때문에 개인정보보호법과의 관계에서 시 정·개선되어야 할 부분이 많다는 시사를 받을 수 있었다. 통신비밀보호법상의 도‧감청은 현저히 감소하고 있는 반면에 동법 및 전기통신사업법이 규정하고 있는 통신비밀자료의 제공은 크게 증가하고 있다. 이러한 환경의 변화는 개인의 프라이버시와 통신비밀이라는 기존 의 논의를 더욱 확장시켜 개인정보자기결정권과 개인정보의 보호라는 정 보화 사회의 담론과 연결된다. 이에 최근의 통신비밀의 보호에 관한 법 령들간의 정합성 문제를 개인정보보호법의 법리에 부합하는 방향으로의 조화적 해석과 법제적 정비방향을 제시함으로써 해결하고자 하였다. 먼 저, 전기통신사업법상 통신자료의 제공은 동법상의 문언해석으로는 통신 사업자의 재량이 허용되어 있는 것으로 보이지만, 개인정보보호법의 법 리에 따라 영장주의가 적용되고 통신사업자의 고지의무를 강화하는 해석 이 타당하다고 본다. 다음으로 통신비밀보호법상 통신사실확인자료의 경 우에는 비록 영장주의에 준하는 사법적 통제가 규정되어 있지만 개인정 보보호법 제18조 제2항 제2호, 제7호에서 제9호까지의 중복적용이라는 법률정합성의 문제가 발생한다. 이에 대해서는 개인정보보호법에서 규율 하지 않는 영장주의를 명시적으로 개별‧특별법에 규정하고 있는 것이므로 통신비밀보호법이 개인정보보호법보다 우선 적용되는 것이 타당하다는 조화적 해석론을 모색하였다.

The objective of this study was to investigate ELF-MF exposure levels of the elderly groups in their living environments using 24-hour personal measurement. In addition, EMF risk perception was investigated. Through evaluations of ELF-MF exposure levels in the proximity of the participants of 58 elderly groups, it was found that TWAam was 1.31 mG (TWAgm: 0.84). ELF-MF exposure levels of the elderly group that live in the proximity of a non-visible power line was high, but there were no statistically significant differences between the non-visible power line elderly group and visible power line elderly group. Moreover, there were no statistically significant differences in ELF-MF exposure according to gender, age, city classification, incomes, residence type, and size. The results showed that the perception of the ELF-MF was very low, as indicated by more than roughly 58.6% of the elderly surveyed saying that they did not know what ELF-MF was. In addition, there was no awareness among the group of how to avoid behavior of EMF from some electric equipment and facilities. Thus, these results will provide useful data for the determination of ELF-MF management and risk communication methods in the living environment for elderly people.

Senior citizens are reported to be highly sensitive to environmental pollutants, including fine particulate matter. The purpose of this study is to investigate the distributions of fine particulate matter concentrations in town halls and senior citizens’ halls, where senior citizens typically spend a lot of time. The results of this investigation will serve as fundamental data for conducting indoor air quality studies and establishing a regional environmental health policy governing senior citizens’ facilities in Yeongwol county in the future. From January 4 to February 1, 2017, PM10 and PM2.5 concentrations in 170 seniors’ facilities located in Yeongwol county were measured. The average concentrations of PM10 and PM2.5 that were measured from each seniors’ facility chosen from Yeongwol county were 25.1 ± 18.9 μg/m3and 12.5 ± 9.3 μg/m3 respectively. Average concentrations and the average of maximum concentrations were lower than the living space standard of 100 μg/m3 for PM10 and the atmospheric environment standard of 50 μg/m3 for PM2.5, which were set by the Ministry of Environment for populations vulnerable to environmental pollution. As a result of analyzing the sources in seniors’ facilities in Yeongwol county during the winter months, it was found that indoor sources of air pollution such as cooking is main sources rather than outdoor sources of air pollution.

초국가적 조직범죄와 마약밀매는 라틴 아메리카에서 가장 주요한 폭력의 원인 이다. 중앙아메리카의 역할은 남아메리카와 멕시코의 역할과 다른데, 중앙아메리 카는 미국으로의 마약 운송을 위한 가교 역할을 한다. 중앙아메리카를 통한 많 은 양의 마약 운송에도 불구하고, 니카라과는 다른 나라들에 비해 상대적으로 낮은 폭력과 낮은 조직범죄집단의 활동이 있는 나라다. 이 연구는 한국의 국가 안보 정책과 마약 거래에 관한 세계적 관심에 대해서 새로운 의견과 전망을 제 시하는 것을 그 목적으로 하였다. 이 연구에서는 중앙아메리카의 다른 국가들과 니카라과 역할 사이의 차이점을 조사하여 조직범죄를 관리하는 특별한 방법을 조사했다. 또한 마약 밀매에 대한 니카라과의 대응이 국제관계, 거버넌스 및 환 경 보호에 미치는 영향이 포함되어 탐색되었다. 마지막으로 연구자들은 정책적 함의와 연구의 한계점에 대해서 논의하였으며, 그리고 이 주제와 관련해서 보다 신뢰할 수 있는 데이터를 수집하기 위한 향후 연구에 대해서 제언하였다.