• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.112-112
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• 1999

고분자 표면에 MeV급 이온을 주입하게 되면 화학적, 광학적, 물리적, 전기적 특성 등 기존의 재래식 공정으로는 불가능한 다양한 특성변화가 일어나게 된다. 본 실험에서는 이온 조사에 따른 micro-hardness의 변화에 중점을 두어 관찰하였다. 수 MeV로 가속시킨 Cl과 C 이온을 Kapton, Teflon, PMMA에 조사량을 바꾸어가며 조사하였다. 이때 조사 전후 고분자 시료의 표면 경도는 depth-sensing nanoindentation technique (Nano Indenter II, USA)을 이용하여 측정하였다. 측정깊이는 극표면 효과와 기측효과의 영향을 무시할 수 없는 100nm로 결정하였다. 또한 이와 같은 경도변화를 규명하기 위하여 각각의 시료에 대해 FTIR, Raman, UV-VIS, RBS, XPS 스펙트럼을 측정하였으며, 조사중에 발생되는 가스상 분자들을 RGA를 이용하여 측정하였다. 1 MeV Cl 이온을 Kato에 4x1015ions/cm2 조사하면 경도가 0.35 GPa에서 7.1GPa로 약 20배 정도 증가하게 되며, 이 경도는 stainless steel 경도 2~3 GPa, martensite steel 8~12와 비교하여 보면 상당히 높은 수준임을 알 수 있다. Teflon과 PMMA 시료의 경우 1MeV Cl 이온 4X1015ions/cm2를 조사시키면 각각 경도가 0.31GPa에서 4.1a, 0.30 GPa에서 3.9GPa로 변화하였으며 Kapton에 비하여 상대적으로 경도의 변화가 적음을 알 수 있었다. 이온 주입된 Kapton의 경우 FT-IR측정에 의하여 이온 조사량이 증가함에 따라 C=O 진동, 이미드그룹의 CONH, tertiary amine의 C-N 흡수 피크가 감소되며, 1X1014ions/cm2 이상의 양이 조사되어야 개질변화가 일어남을 알 수 있었다. XPS 측정 결과 Kapton에 조사되는 이온양이 증가할수록 C=O, C-O 및 C-N의 탄소는 감소하고 페닐고리 탄소가 증가함을 알 수 있었다. 또한 이온 조사 중 측정한 RGA에서도 CO 가스가 대량 방출되는 현상을 관찰하였으며 FTIR 및 XPS에서의 C=O 결합의 감소와도 일치하였다. RBS에 의한 CNO 원소의 변화에서도 다른 원소보다 O의 감소가 현저하게 나타남을 확인하였다. UV-VIS 측정을 통해 조사 이온량에 따라 에너지 준위가 변동하여 흡수스펙트럼이 장파장으로 확대됨을 알 수 있었으며, 이는 공액 2중 결합의 형성에 의한 $\pi$-전자 및 기타 결함에 기인한다. PMMA 및 Teflon의 경우 FTIR 측정에 의하여 이온 조사됨에 따라 function group 들의 peak가 세기가 감소되면서 완만해지는 경향을 보이며 원래의 구조를 상실하게 된다. PMMA와 Teflon은 이온 조사가 되면 가교형서보다는 사슬절단이 주로 일어나므로 가교형성이 잘 일어나는 Kapton보다는 상대적으로 경도의 증가가 적음을 알 수 있었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.47-53
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• 2015

Storage root yield of sweetpotato was decreasing owing to continuous sweetpotato cropping, debasement of soil physical properties, increasing incidence of pest and disease. This study was conducted to evaluate the changes in physicochemical properties of the soil owing to subsoiling (subsoiling to 50 cm depth), and the effect on growth and yield of sweetpotato. The subsoiling treatments included subsoiling treated every year for two years, subsoiling in the first year, and no subsoiling control. The soil physical properties measured were bulk density, hardness, porosity, three phase. Bulk density, porosity, soild (%) of three phase were improved by subsoiling in topsoil and subsoil. Main vine length and vine yield in subsoiling soil were higher than those in no subsoiling soil, but those were not significantly different. Yield of marketable storage root in subsoiling soils treated every year for two years and treated in the first year was more increased 17% and 20% than no subsoiling soil, respectively. The number of marketable storage root per plant was also higher in subsoiling soils than no subsoiling soil, but it was not significantly different. Soluble solid contents and total free sugar contents of storage root of sweetpotato were not significantly different among the treatments. These results show that improving soil physical properties by subsoiling could promote high yield of marketable storage root in continuous sweetpotato cropping field.

• Journal of the Korean association of regional geographers
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• v.2 no.1
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• pp.39-49
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• 1996

There is a limestone basin surrounded by the mountains consisted of Paleozoic sedimentary and metamorphic rocks in the Masung, Munkyung city, Kyungsangpook do. The purpose of this paper is to elucidate the geomorphic processes of the gentle hillslopes in the marginal piedmont of Masung basin. To do so, I analyzed deposits over hillslopes and the relation ship between the distance from the divide and the height(above sea level) at the longitudinal profile of the hillslope, and considered interrelation between the distributions of the gentle hillslopes(less than 230m) and lithology. Geomorphic processes of Masung basin are as follow: (1) The depth of deposits over hillslope increases toward downstream of the hillslope. Most gravels within deposits, whose lithology is limestone, are those eroded at the boundary(overthrust fault zone) between the back-mountain and the hillslope. Deposits at the outward margin of hillslope is well sorted. and moderately imbricated. (2) Hillslope at the margin of the basin(160-230m asl) is formed by the action of 'the flow with channel'. At the boundary between the soft rock(limestone; basin floor) and hard rock(sedimentary and metamorphic rock; back-mountain), the relatively weak limestone is eroded to fresh bedrock by the subsequent action of the overland flow, and therefore discontinuity in slope appeared. (3) After hills lopes were formed, sediments(boulders and fine material) produced during dissection in back-mountain buried deposits over hillslope. In conclusion, geomorphic processes of Masung basin is 'differential erosion due to differentiation of lithological hardness' having suggested as geomorphic processes of granitic basin. However it is not 'removal of weathering material due to sheetflow' but 'erosion due to the overland flow with channel'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.497-502
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• 1997

A seed pelleting technique was developed for easy handling of small sesame seeds (Chinbaeckkae) and for direct seeding in field. The mixture of pelleting material, binder(sodium alginate) and seeds were dropped in 100mM CaCl$_2$ solution. Charcoal was appeared as a best material among all to make pellets with the characters of hardness, breakdown, destruction rate and germination percentage. Zeolite formed the hardest pellet seeds among the materials and 1~3 seeds contained in a pellet on the treatment of 87g of sesame seeds mixed in 1$\ell$ CaCl$_2$ solution was estimated optimum rate of seed mixure with few appearance of seedless pellet. The moisture absorption rate was greater in the order of peat＋charcoal > peat > charcoal > zeolite. Germination percentage of pelleted seeds with charcoal was the best and similar to that of common non-treated seeds. Germination percentage of pelleted seeds by sowing depth of exposing a quarter of pellet seeds on the surface of vermiculite germination test box and were 92％ in charcoal treatment and was the best among all released materials.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.752-757
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• 2017

Analysis has been performed for the penetration of a long-rod into MMC/Ceramic layered armour system with several shot test and a series of simulations. Two types of MMC plate have been fabricated by a liquid pressing method; A356/45%vol.%SiCp with a uniform distribution of SiC particle and Al7075/45%vol.B4Cp with B4C particle. The mechanical properties were measured with the high-speed split Hopkins bar test, hardness test and compression test. The popular Simplified Johnson-Cook model was adopted to represent the material characteristics for FEM simulations. The performance of the MMC applied armour system has been made by comparing with the semi-infinite mild steel target using the depth of penetration(DOP). The results show that placing ceramic front layer provides a certain gain in protection, and that placing another ductile front layer provides a further gain. The application of MMC is found to be attractive.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.61-69
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• 2004

Building stones are used mainly as a material for making decoration and sculpture, and consequently they must have predominant physical properties extensively. Among various physical properties, the coefficient of pore dominates the usefulness of building stones, so the plans were made for establishing the quality classification of building stones with respect to the nature of pore. For this study, bore-hole core samples according to the depth of the biotite granites and the granitic gneiss were applicated. From the related chart between porosity and absorption ratio, Mungyeong granitic gneiss($Gn_1$) shows the widest phase of distribution in the range of measurement values, and the values decrease in the order of Pocheon granite($Gr_2$) and Mungyeong granite($Gr_1$) in the range. The strength of each rock mass varies with the degree of alteration. Also in correlation between compressive strength and tensile strength, the range of measurement values decrease in the order of $Gn_1$, $Gr_2$and $Gr_1$. Porosity is adopted as a representative physical property for establishing the quality classification of building stones, and then relative evaluation was made with regard to various physical properties. From the related chart between porosity(n)-specific gravity(G), absorption ratio(Ab), compressive strength(${\sigma}_{c}$), tensile strength(${\sigma}_{t}$), shore hardness(Hs) and Young's modulus($E_{t}$), standard of each grade is established.

• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.456-460
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• 2011

Recently, the size of currently-researched components and devices reduces nano-scale. Thus, it is important and emphasizes the analyses of physical properties in nano scale. Especially, the mechanical properties are not over micro-scale components but nano-scale components with different characteristics that has been reported. However, most analytical methods for currently studying in nano-scale are related to spectroscopy and electronics, affected the limitation of viewing size that these methods give only average information. In this research, the representative nanotribology analyses, nano-indenter study the physical and mechanical properties of W-N thin film for nano region and nano depth within nano-scale that the thickness of W-N diffusion barrier has less than tens of nanometers. The Scanning probe microscopy (SPM) study the surface image. From these results, the hardness of W-N thin film underneath the nano-surface decreased from 57.67 GPa to 9.1 GPa according to the increase of nitrogen gas flow. The elastic modulus of W-N thin film underneath the nano-surface also decreased from 575.53 GPa to 178.1 GPa.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.971-978
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• 2012

Vacuum carburizing is supposed to be the superior process to the gas carburizing. However, the vacuum carburizing has the stage in which hydrocarbon gas is supplied into the furnace to be pyrolysis, and consequently the stable heat treatment is hard to achieve due to the soot from the hydrocarbon pyrolysis. Recently, many studies have been made which utilize acetylene gas to overcome this defects. In this paper, the carburizing and the diffusion periods have been selected based on the Harris experimental formula, and the mechanical properties of the vacuum carburized specimen have been compared with those of the gas carburized SCM415H specimen to identify the feasibility of the $CO_2$ free vacuum carburizing process. The result showed that the vacuum carburized materials used have no oxidization of the grain boundaries, and show the 29.8% higher effective hardness depth and the acceptable tensile strength.

• Journal of muscle and joint health
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• v.3 no.1
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• pp.50-62
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• 1996

The purpose of this study was to identify and construct a substantive theory about the experience of fatigue among the female elderly with osteoarthritis. The interviewees were 6 female elderly with osteoarthritis. Of them 3 were admitted General hospital, the remaining 3 didn't admitted hospital. The data were collected through in-depth interviews by the investigators from May 20th, 1995 to June 19th, 1995. The collected data were coded into concepts and categories according to Strauss & Corbin's grounded method. The data thus collected were analyzed immediatly after interviews and fed into next round of interviews until the data collection reaches the saturation point where no additional concepts emerge. The 35 concepts were from analyzing the grounded data. The results of this study were as follows : 'change of the health condition','change of the life pattern', 'physiologic change', 'change of the coping pattern', 'performance of homework', 'activity daily living', 'tireness', 'ache', 'change of general apperance', 'sleep disturbance', 'powerlessness'. 'Physiologic unbalance', 'change of the family dynamics', 'physical imbalance', 'loss of the control', aviodance', 'conversion', 'leaving', 'indifference', 'hesitation', 'the pursue of information and trial', 'the western therapy', 'heat therapy', 'the oriental therapy','exercise', 'weight control', 'support', 'solution', 'being as before', 'adding more'. Six categories emerged from the analysis of ground data. They were as follows : 'stimuli', 'fatigue', 'passive coping', 'active coping', 'disolution', 'remains'. 13 hypothesis were derived from the integration of categories as follows : 1. The stronger the stimulus as perceived by the subjects, the more the fatigue will exrerience. 2. The more severe the fatigue, the more severe the tireness. 3. The more severe the fatigue, the more the hardness. 4. The more severe the fatigue, the more the variability of appear will experience. 5. The more severe the fatigue, the more the pain will experience. 6. The more severe the fatigue, the more the insomnia will experience. 7. The more severe the fatigue, the more the powerless will experience. 8 The more severe the fatigue, the more the psychological unbalance will experience. 9. The more severe the fatigue, the more variability of the family dynamics will experience. 10. The more severe the fatigue, the more the physical unbalance will experience. 11. The more severe the fatigue, the more loss of control will experience. 12. The subjects who experienced the fatigue will be to show passive coping and active coping mechanism.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.109-113
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• 2007

In order to establish the fertilization and soil management method in Gyehwa reclaimed tidal land, we investigated soil property and actual farming condition. Soil properties of 100 field paddy soil and farming surveys of 177 farm households were conducted. Average of effective soil depth was 17.8 cm, which was very smaller than the optimum level 50 cm. The hardness and bulk density of subsoil were $12.40kg\;cm^{-2}$ and $1.59g\;cm^{-3}$, respectively. These results showed that soil physical condition of Gyehwa reclaimed tidal land was very poor. Soil salinity ranged from 0.03 to 0.12%, and average of pH was 6.0, which implied that desalinization of Gyehwa reclaimed tidal land was progressed. However, soil nutrients in Gyehwa reclaimed tidal land were very unbalanced conditions as following, available phosphate $58mg\;kg^{-1}$, available silicate $85mg\;kg^{-1}$, cation exchangeable capacity $7.4cmolc\;kg^{-1}$ and organic matter $8.6g\;kg^{-1}$. On the farm household in Gyehwa reclaimed tidal land, fertilization amounts were $200-54-61(N-P_2O_5-K_2O)kg\;ha^{-1}$ They mainly practiced spring tillage(84%) rather than autumn tillage(16%), and only 14% of them applied rice straw annually in the paddy soil.