• 한국정밀공학회지
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• 제18권3호
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• pp.182-188
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• 2001

An experiment is carried out to investigate the characteristics of blanking for copper alloy C194 (t=0.254mm), a kind of IC lead frame material. By varying clearance between die and punch, the shapes of shear profile are examined. Finite element analysis with element deletion algorithm for ductile fracture mode is also carried out to study the effect of clearance theoretically and to compare with experimental results. The rectangular shape specimen with four different corner radius is used to study the characteristics of blanking for straight side and corner region simultaneously. As the result, the ratios measured from the experiment of roll over, burnish, and fracture zone based on intial blank thickness are compared with those of FE analysis. Both experiment and FE analysis show that the amount of roll over and fracture is increased as the clearance increases. It has been found that larger clearance is required than that of straight region when the radius of corner is less than thickness of blank, in order to maintain same quality of shear profile at the corner region.

• 한국대기환경학회지
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• 제13권5호
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• pp.361-369
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• 1997

In order to investigate the abundance and transboundary fluxes of air pollutants over the Yellow Sea, airborne measurements were made aboard the SF-600 aircraft (Pan-Asia Engineering) in March, 1996. The data presented in this paper are preliminary results and airborne experiment will be carried out until 1999. The vertical profile of relevant meteorological parameters such as temperature, water vapor, wind direction and wind speed were also observed at Taean. Mixing layer height was about 1000~1100m during the flights. The SO$_2$ and NO$_{x}$ concentrations were 3~6 ppb and 5~7 ppb below 1000 m, within 1 ppb and 3~5 ppb at 1000~2000m, respectively. Backward trajectory analyses were also carried out. A mathematical method by Lelieveld et al.(1989) was used to estimate the flux of air pollutants through the planetary boundary layer of Yellow Sea area. Transboundary fluxes were calculated using the measurement results with respect to the pollutants concentration, depth of the planetary boundary layer, wind speed and wind direction. The estimated transboundary flux of SO$_2$through the western boundary of Korea was about 39~42 tons/hour.r.

• 한국물환경학회지
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• 제31권3호
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• pp.262-271
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• 2015

Laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fiber media under a high filtration rate (over 1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analyzed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used (PAC in this study) greatly affected the performance of this particular fiber filter. Long term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Finally, a comparison was carried out with other high rate filter systems which are either being tested for use in experimental studies, or are already commercially available.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.329-334
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• 2002

Preflex beam is a method of construction to hold the Pre-compressive stresses over the concrete pier by the Preflexion load. During the fabrication of the girder, welding causes the welding residual stresses. The welding residual stresses must be relieved to generate the accurate compressive pre-stresses that is designed. On this study, to find out the thermal distribution characteristics on the girder by welding, both the three-dimensional finite element analysis and the two-dimensional finite element analysis in a quasi-steady state is carried out. After comparing with each result between the three-dimensional analysis and the two-dimensional analysis, finite element analysis is carried out against the actual girder and analyze welding thermal distribution characteristic over the preflex beam and obtain the input data for the analysis of the welding residual stresses.

• PNF and Movement
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• 제9권1호
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• pp.1-9
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• 2011

Purpose : The purpose of this study is to analyze the effect of closed-chain exercise on weight supporting rate change within hemiplegic side and static dynamic balance ability in stroke patients. Methods : The subjects of the study were 13 hemiplegic patients who carried out closed-kinematic chain exercise program over 6 weeks. The exercises of the program are stand to sit with stall bar, stair-up & down by a hemiplegic leg and bridging exercise crossing the non-hemiplegic leg onto the hemiplegic leg. Each exercise was carried out over 3 sets of 10reps. Results : The results of this study were summarized as follows: 1. After intervention, there was a statistically significant change in the weight supporting rate within hemiplegic and non-hemiplegic side(P<0.05). 2. After intervention, there was a statistically significant change in the static balance(FICSIT-4) ability(P<0.05). 3. After intervention, there was a statistically significant change in the dynamic balance(FSST, TUG, FRT) ability(P<0.05). Conclusion : The results of the study suggests that closed-chain exercise program in stroke patients improves their weight supporting rate and enhance the static dynamic balance.

• 제어로봇시스템학회논문지
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• 제20권10호
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• pp.1057-1062
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• 2014

This paper proposes a tip-over detection method for a mobile robot using a support inscribed circle defined as an inscribed circle of a support polygon. A support polygon defined by the contact points between the robot and the terrain is often used to analyze the tip-over. For a robot moving on uneven terrain, if the intersection between the extended line of gravity from the robot's COG and the terrain is inside the support polygon, tip-over will not occur. On the contrary, if the intersection is outside, tip-over will occur. The terrain is detected by using an RGB-D sensor. The terrain is locally modeled as a plane, and thus the normal vector can be obtained at each point on the terrain. The support polygon and the terrain's normal vector are used to detect tip-over. However, tip-over cannot be detected in advance since the support polygon is determined depending on the orientation of the robot. Thus, the support polygon is approximated as its inscribed circle to detect the tip-over regardless of the robot's orientation. To verify the effectiveness of the proposed method, the experiments are carried out using a 4-wheeled robot, ERP-42, with the Xtion RGB-D sensor.

• 아시안잔디학회지
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• 제15권2호
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• pp.87-104
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• 2001

This Study was carried out to investigate on the environmental effects of golf courses and to find a solution to the negative effects in Korea. The results were ai follows. 1. There were 152 golf courses opened in December 2000. 113 golf courses were member-ship and 39 golf courses were public. Users (golfer) were over 12,000,000 in 2000. 2. Total area of golf courses was 0.8% as compared with total area of farmland in 1999. Total amount of agricultural chemicals used in golf courses was 0.3% of total amount of agricultural chemicals used in Korea. The remaining amount of agricultural chemicals in golf courses tested were almost below the permitted limits. 3. Recently, total amount of fertilizers in green decreased 5~7g/$m^2$/year as compared with the recommended. 4. The control by antagonistic microorganisms and the fertilizing of the organic matter or the organic fertilizer were effective to decrease the amount of agricultural chemicals used. To success the control of microorganisms, active antagonistic microorganisms had to be applied over the recommended dose eve교day. Though fertilizing of organic fertilizer, slow release fertilizer, was effective to suppress dollar spot, necrotic ring spot. fungicides were required as a supplementary means when disease symptom was very heavy. 5. Zoysiagrass was fertilized intensively from May to August. Cool-season grasses were fertilized intensively from March to May and September to October. The fall fertilizing of Zoysiagrass was carried out to the begining of October. The fall fertilizing of cool-season grasses were carried out to the end of November or the begining of December. The fertilizing amount of Zoysiagrass was 10g/$m^2$/year. The fertilizing amount of bentgrass was 25~27g/$m^2$/year.

• 대한치과보철학회지
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• 제38권1호
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• pp.12-25
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• 2000

To demonstrate possible influences of general bone density on the mandible, histomorphometric analysis was carried out in mandibles and iliac bones and the correlation of the two bone densities was tested. Comparison of bony density in women and men over 60 years in the mandible was carried out too. Quantitative computed tomography(QCT) was taken in cross-section of mandibles at the same site where histomorphometric analysis was peformed to evaluate the reliability of QCT. The analysis included 40 cadavers with no known diseases affecting the bones. The subjects consisted of 15 females and 25 males with a mean age of 60.3 years. Spearman correlation analysis and Wilcoxon rank sum test was performed. The results were as follows. 1. There was statistically no correlation between the mandible and iliac bone in the values of corrected cortical width(CCW), cortical porosity(POR) in cortex, and total bone volume(TBV), mean trabecular plate thickness(MTPT), mean trabecular plate density(MTPD), and mean trabecular plate separation(MTPS) in trabecular bone. 2. Comparison of women and men over 60 years, men had statistically higher bone density than women except fir POR of buccal and lingual cortex, and WTPD of alveolar trabeculae in mandible. 3. There was statistically significant correlation between TBV of trabecular bone and CT No., but not between POR and CT No. in mandible. According to the results above, there was no correlation between mandible and iliac bone density and between mandibular bony density and age. Further studies are required to support the results. A more noninvasive method to be able to measure the bone density of mandible should be developed and it is necessary to accumulate data on the normal values of bone density of mandible according to age and sex. Further study should be carried out about QCT to measure mandibular bony density using QCT.

• 공업화학
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• 제23권1호
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• pp.28-34
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• 2012

본 연구에서는 UASB 반응조를 이용하여 음폐수 탈리액을 원료로 하여 중온소화($35{\pm}0.5^{\circ}C$)와 고온소화($55{\pm}0.5^{\circ}C$)법을 통한 운전을 실시하였다. 20일 동안은 중온소화로 운전을 하면서 5일 간격으로 유출수 재순환 비를 단계적으로 변화시켰다. 고온소화 역시 중온소화와 마찬가지 조건으로 운전을 실시하였다. 실험결과 중온소화 시 유기물제거율은 90% 이상, 메탄수율은 약 66~70%로 나타났다. 고온소화 시 유기물제거율은 80% 이상, 메탄수율은 약 62~68%로 나타났다. 또한, 유출수 반송을 3Q 이상으로 반송하여 운전할 경우 경제적이며 안정적인 운전을 할 수 있었다.

• 기술사
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• 제16권3호
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• pp.5-23
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• 1983

On the Seoul Metropolitan Subway Construction of No. 3, 4 Line, the total length is 57 Km and it is now undergoing almost 55％ progress. The working method is classified into Open Cut of 70% and the rest of 30% tunnelling method in the 48 job site. Above tunnelling method is execute by American Steel Support System and the rest of 10 job site carried out by New Austria Tunnelling Method. This paper describes Blasting Standardizations works on the above Tunnelling ' Open Cut Method under big slogan, first safety, second execution. As a superintendent, I strived standardization of works with Better powder, Better Drills ' Better Pattern. Geological structure of Seoul area is composed by Jurassic Granite and also the above rockgroup are over burden by Alluviums as a Unconformity. First of all, I carried out the standard amount of powder and burden through experimental standard blasting by each powder as following Blasting works in the subway construction is surrounding shop Building, under pass the city river and also under pass highest building basement floor. I made allowable Blasting Vibration Value by West-Germany Vornorm DIN 4150, Teil 3 and should measure each blasting works as fellows all of powder is used basically Low-Gravity and Low Velocity such as Slurry, Ammonium Nitrate ' Finex I, II. for Smooth Blasting Instead of Gelatin Dynamite. Electric Detonation Cap is used basically M/S Delay Cup instead of Electric delay ' Simultaneous cap. I applied following formula V=KW3/4 $D^{-2}$ V=Particle Velocity (Cm/sec) K=Ginh Huh's Value W=Delay Charge (Kg) D=Distance(m) In the Open Cut, within 1m distance from H-pile I made to use the Concrete breaker, as following V=7W/$^{0.5}$V/$^{-1.75}$ On the Concentrate Building area, I advise to use Light class drill ø36m Bit and advance 1.1m per round blasting the three boom jumbo drill over ø45mm used only suburb of city.e Light class drill ø36m Bit and advance 1.1m per round blasting the three boom jumbo drill over ø45mm used only suburb of city.