• Journal of Periodontal and Implant Science
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• 제42권6호
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• pp.196-203
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• 2012

Purpose: The aim of this study was to evaluate the clinical efficiency of the subepithelial connective tissue graft (SCTG) with and without plasma rich in growth factor (PRGF) in the treatment of gingival recessions. Methods: Twenty bilateral buccal gingival Miller's Class I and II recessions were selected. Ten of the recessions were treated with SCTG and PRGF (test group). The rest ten of the recessions were treated with SCTG (control group). The clinical parameters including recession depth (RD), percentage of root coverage (RC), mucogingival junction (MGJ) position, clinical attachment level (CAL), and probing depth (PD) were measured at the baseline, and 1 and 3 months later. The data were analyzed using the Wilcoxon signed rank and Mann-Whitney U tests. Results: After 3 months, both groups showed a significant improvement in all of the mentioned criteria except PD. Although the amount of improvement was better in the SCTG+PRGF group than the SCTG only group, this difference was not statistically significant. The mean RC was $70.85{\pm}12.57$ in the test group and $75.83{\pm}24.68$ in the control group. Conclusions: Both SCTG+PRGF and SCTG only result in favorable clinical outcomes, but the added benefit of PRGF is not evident.

• 공업화학
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• 제28권2호
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• pp.206-213
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• 2017

활성탄을 사용하여 수용액으로부터 crystal violet 염료의 흡착에 대해 조사하였으며, 흡착제의 양, 초기농도와 접촉시간 및 온도를 흡착변수로 사용하여 수행하였다. 흡착평형관계는 Langmuir 등온식에 잘 맞았다. 평가된 Langmuir 분리 계수($R_L=0.02{\sim}0.106$)를 바탕으로 이 흡착공정이 효과적인 처리(0 < $R_L$ < 1)가 가능하다는 것을 알았다. 흡착동력학 데이터는 유사 2차 반응속도식에 잘 맞는 것으로 나타났다. Gibbs 자유에너지(-1.61~-11.66 kJ/mol)와 엔탈피(147.209 kJ/mol)는 흡착공정이 자발적이고 흡열반응으로 진행된다는 것을 나타냈다. 등량흡착열은 표면덮임이 증가됨에 따라 흡착제-흡착질의 상호작용이 제한되어 표면부하량이 증가할수록 작아졌다.

• 공업화학
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• 제21권5호
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• pp.575-580
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• 2010

우리나라는 전국토의 70%가 산림지역으로 1990년대 중반 이후 산불발생 건수가 지속적으로 증가하고 있고, 그 규모 또한 대형화되는 추세이다. 산림 내에 퇴적된 낙엽, 초본류, 침엽수 및 활엽수 등이 산불발생 시 매개체가 되며, 이들 수종별 연소 및 열분해 특성에 대한 연구는 미미한 실정이다. 본 발표에서는 국내 산림의 대표적 활엽수인 굴참나무 잎을 대상으로 TGA를 이용해 열분해반응 및 연소 특성에 대한 연구를 수행하였다. 굴참나무 잎은 $239^{\circ}C$ 부근에서 발화가 시작되며 열분해는 $250^{\circ}C$에서부터 시작되었다. TGA 분석으로부터 얻은 실험데이터는 미분법을 적용하여 전화율 변화에 따라 활성화에너지와 전지수인자를 계산하였다. 열분해반응에서 활성화에너지는 전화율 증가에 따라 증가하였으나, 연소과정에서의 활성화에너지는 감소하는 경향을 나타냈다.

• 보건행정학회지
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• 제24권2호
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• pp.109-119
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• 2014

In accordance with the government's plan to expand the national health insurance (NHI) coverage for severe diseases such as cancer, heart disease, cerebrovascular disease, and rare and incurable disease, the diagnostic ultrasound services have been covered by NHI from October 1, 2013. The quality is very important factor in providing diagnostic services because they influence on the diagnosis, treatment, and outcome of diseases. In particular, equipments and health care providers plays an important role in providing qualitative services. The purpose of this paper is to examine the major feature of ultrasound services covered by health security system and to review quality assurance policies in other countries such as Australia, Japan, the USA, and Canada. In addition, we assessed the implication of those policies. We especially put emphasis on the types and qualifications of healthcare professionals and measures to manage equipments. All countries have reviewed on policies to promote the quality such as educational requirements of professionals or restrictions on the duration of equipment usage. Various measures should be implemented to assure the qualitative ultrasound service.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.557-565
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• 2014

We report the effect of basal-plane stacking faults (BSFs) on X-ray diffraction (XRD) of non-polar (11$\underline{2}$0) a-plane GaN films with different $SiN_x$ interlayers. Complete $SiN_x$ coverage and increased three-dimensional (3D) to two-dimensional (2D) transition stages substantially reduce BSF density. It was revealed that the Si-doping profile in the Si-doped GaN layer was unaffected by the introduction of a $SiN_x$ interlayer. The smallest in-plane anisotropy of the (11$\underline{2}$0) XRD ${\omega}$-scan widths was found in the sample with multiple $SiN_x$ layers, and this finding can be attributed to the relatively isotropic GaN mosaic resulting from the increase in the 3D-2D growth step. Williamson-Hall (WH) analysis of the (h0$\underline{h}$0) series of diffractions was employed to determine the c-axis lateral coherence length (LCL) and to estimate the mosaic tilt. The c-axis LCLs obtained from WH analyses of the present study's representative a-plane GaN samples were well correlated with the BSF-related results from both the off-axis XRD ${\omega}$-scan and transmission electron microscopy (TEM). Based on WH and TEM analyses, the trends in BSF densities were very similar, even though the BSF densities extracted from LCLs indicated that the values were reduced by a factor of about twenty.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.556-559
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• 2007

The Urban Environmental Quality (UEQ) indicates a complex and various parameters resulting from both human and natural factors in an urban area. Vegetation, climate, air quality, and the urban infrastructure may interact to produce effects in an urban area. There are relationships among air pollution, vegetation, and degrading environmental the urban heat island (UHI) effect. This study investigates the application of multi-spectral remote sensing data from the Landsat ETM and TM sensors for the mapping of air quality and UHI intensity in Seoul from 2000 to 2006 in fine resolution (30m) using the emissivity-fusion method. The Haze Optimized Transform (HOT) correction approach has been adopted for atmospheric correction on all bands except thermal band. The general UHI values (${\Delta}(T_{urban}-T_{rural})$) are 8.45 (2000), 9.14 (2001), 8.61 (2002), and $8.41^{\circ}C$ (2006), respectively. Although the UHI values are similar during these years, the spatial coverage of "hot" surface temperature (>$24^{\circ}C$) significantly increased from 2000 to 2006 due to the rapid urban development. Furthermore, high correlations between vegetation index and land surface temperature were achieved with a correlation coefficients of 0.85 (2000), 0.81 (2001), 0.84(2002), and 0.89 (2006), respectively. Air quality is shown to be an important factor in the spatial variation of UEQ. Based on the quantifiable fine resolution satellite image parameters, UEQ can promote the understanding of the complex and dynamic factors controlling urban environment.

• 한국산림과학회지
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• 제90권6호
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• pp.683-691
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• 2001

산림의 수원함양기능 지표로서 표층토양에서의 조공극률(組孔隙率)(pF2.7)에 영향하는 인자를 밝히기 위해 1995년 3월부터 10월까지 전국의 활엽수림 표본조사구를 대상으로 입지, 토양, 임분환경인자 등 총 24종에 대하여 spss/pc+를 이용하여 상관 분석하였다. 표층토양에서의 조공극률에 영향을 미치는 인자는 B층 토양에서의 조공극률, 하층식생 피복도, 표층 토양의 유기물함량비, F층 두께 등 4개 인자가 유의한 정(正)의 상관관계를, 표층토양의 견밀도, 10cm 깊이의 토양견밀도가 각각 5%, 1% 수준에서 유의한 부(負)의 상관관계를 나타내었다. Stepwise를 이용한 다중회귀분석결과 산림의 수원함양기능 증대에 영향하는 표층토양에서의 조공극률에 영향하는 인자는 B층 토양에서의 조공극률, 유기물함량비 등 2개 인자이었다.

• 한국도로학회논문집
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• 제20권1호
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• pp.47-58
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• 2018

PURPOSES : The purpose of this study is to evaluate the mechanical properties of a cold-recycling asphalt mixture used as a base layer and to determine the optimum emulsified-asphalt content for ensuring the mixture's performance. METHODS : The physical properties (storage stability, mixability, and workability) of three types of asphalt emulsion (CMS-1h, CSS-1h, and CSS-1hp) were evaluated using the rotational viscosity test. Asphalt emulsion residues, prepared according to the ASTM D 7497-09 standard, were evaluated for their rheological properties, including the $G*/sin{\delta}$and the dynamic shear modulus (${\mid}G*{\mid}$). In addition, the Marshall stability, indirect tensile strength, and tensile-strength ratio (TSR) were evaluated for the cold-recycling asphalt mixtures fabricated according to the type and contents of the emulsified asphalt. RESULTS : The CSS-1hp was found to be superior to the other two types in terms of storage stability, mixability, and workability, and its $G*/sin{\delta}$ value at high temperatures was higher than that of the other two types. From the dynamic shear modulus test, the CSS-1hp was also found to be superior to the other two types, with respect to low-temperature cracking and rutting resistance. The mixture test indicated that the indirect tensile strength and TSR increased with the increasing emulsified-asphalt content. However, the mixtures with one-percent emulsified-asphalt content did not meet the national specification in terms of the aggregate coverage (over 50%) and the indirect tensile strength (more than 0.4 MPa). CONCLUSIONS : The emulsified-asphalt performance varied greatly, depending on the type of base material and modifying additives; therefore, it is considered that this will have a great effect on the performance of the cold-recycling asphalt pavement. As the emulsified-asphalt content increased, the strength change was significant. Therefore, it is desirable to apply the strength properties as a factor for determining the optimum emulsified-asphalt content in the mix design. The 1% emulsified-asphalt content did not satisfy the strength and aggregate coverage criteria suggested by national standards. Therefore, the minimum emulsified-asphalt content should be specified to secure the performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1638-1654
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• 2018

The heterogeneous network (HetNet) has been one of the key technologies in Long Term Evolution-Advanced (LTE-A) with growing capacity and coverage demands. However, the introduction of femtocells has brought serious co-layer interference and cross-layer interference, which has been a major factor affecting system throughput. It is generally acknowledged that the resource allocation has significant impact on suppressing interference and improving the system performance. In this paper, we propose a hybrid-clustering algorithm based on the $Mat{\acute{e}}rn$ hard-core process (MHP) to restrain two kinds of co-channel interference in the HetNet. As the impracticality of the hexagonal grid model and the homogeneous Poisson point process model whose points distribute completely randomly to establish the system model. The HetNet model based on the MHP is adopted to satisfy the negative correlation distribution of base stations in this paper. Base on the system model, the spectrum sharing problem with restricted spectrum resources is further analyzed. On the basis of location information and the interference relation of base stations, a hybrid clustering method, which takes into accounts the fairness of two types of base stations is firstly proposed. Then, auction mechanism is discussed to achieve the spectrum sharing inside each cluster, avoiding the spectrum resource waste. Through combining the clustering theory and auction mechanism, the proposed novel algorithm can be applied to restrain the cross-layer interference and co-layer interference of HetNet, which has a high density of base stations. Simulation results show that spectral efficiency and system throughput increase to a certain degree.

• Journal of Ecology and Environment
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• 제33권4호
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• pp.377-389
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• 2010

Understanding the factors relevant to endangerment and the patterns of habitat locations in relation to protected areas is critically important for the conservation of rare species. Although 64 plant species have recently been listed as endangered species in Korea, this information has, until now, not been available, making appropriate management and conservation strategies impossible to devise. Thus, we collected information on potentially threatening factors, as well as information on the locations in which these species were observed. The potentially threatening factors were classified into seven categories. National parks, provincial parks, ecosystem conservation areas, and wetland conservation areas were defined as protected conservation areas. Korean digital elevation model data, along with the maps of all protected areas were combined with the maps of endangered plant species, and analyzed via Geographic Information Systems (GIS). Excluding the category of "small population", endangered plant species in Korea were associated more frequently with extrinsic factors than intrinsic factors. Considering land surface only, all conservation areas in Korea totaled 4.9% of the land, far lower than International Union for Conservation of Nature and Natural Resources (IUCN)'s 10% coverage target. At the species level, 69% of the endangered plant species were detected in conservation areas, mostly in national parks. However, this result demonstrates that 31% of endangered species inhabit areas outside the conservation zones. Furthermore, at the habitat level, a large proportion of endangered species were found to reside in unprotected areas, revealing "gaps" in protected land. In the face of rapid environmental changes such as population increases, urbanization, and climate changes, converting these gap areas to endangered species' habitats, or at least including them in habitat networks, will help to perpetuate the existence of endangered species.