• Analytical Science and Technology
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• v.22 no.5
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• pp.386-394
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• 2009

Formaldehyde is used in lether manufacture, a dry plate and an explosive. It is by-product of ozonizing process in filtration plant. The effects of exposure are eye pruritus, tickle, runing nose, blocking nasal passages and headache. It also makes a dried throat and causes inflammation. It is classified as B1 group for inhalation by US. EPA, which can cause cancer in human. For analysis of formaldehyde, formaldehydes-DNPH derivative was extracted with solid cartridge and was analyzed by High Performance Liquid Chromatography/Diode Array Detector (HPLC/DAD). The detection limit was $3{\mu}g/L$ and the recoveries were 72.3~109.1% (RSD 2.9~11.5%). Water samples were collected in four Korean rivers, four times per year seasonally for 10 years from 1998 to 2007. The monitoring results were 48.8% (630/1291), $5.15{\sim}101.9{\mu}g/L$ in purified water. Because of non-carcinogen in drinking water, hazard index is calculated with RfD. Results of excess cnacer risk was below 1 and was considered as safe value.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.103-109
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• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.57-65
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• 2019

Purpose: The purpose is to clarify the effect of additional scattering ratio on the edge of the block according to the increasing block thickness with low melting point lead alloy and pure lead in electron beam therapy. Methods and materials: $10{\times}10cm^2$ Shielding blocks made of low melting point lead alloy and pure lead were fabricated to shield mold frame half of applicator. Block thickness was 3, 5, 10, 15, 20 (mm) for each material. The common irradiation conditions were set at 6 MeV energy, 300 MU / Min dose rate, gantry angle of $0^{\circ}$, and dose of 100 MU. The relative scattering ratio with increasing block thickness was measured with a parallel plate type ion chamber(Exradin P11) and phantom(RW3) by varying the position of the shielding block(cone and on the phantom), the position of the measuring point(surface ans depth of $D_{max}$), and the block material(lead alloy and pure lead). Results : When (depth of measurement / block position / block material) was (surface / applicator / pure lead), the relative value(scattering ratio) was 15.33 nC(+0.33 %), 15.28 nC(0 %), 15.08 nC(-1.31 %), 15.05 nC(-1.51 %), 15.07 nC(-1.37 %) as the block thickness increased in order of 3, 5, 10, 15, 20 (mm) respectively. When it was (surface / applicator / alloy lead), the relative value(scattering ratio) was 15.19 nC(-0.59 %), 15.25 nC(-0.20 %), 15.15 nC(-0.85 %), 14.96 nC(-2.09 %), 15.15 nC(-0.85 %) respectively. When it was (surface / phantom / pure lead), the relative value(scattering ratio) was 15.62 nC(+2.23 %), 15.59 nC(+2.03 %), 15.53 nC(+1.67 %), 15.48 nC(+1.31 %), 15.34 nC(+0.39 %) respectively. When it was (surface / phantom / alloy lead), the relative value(scattering ratio) was 15.56 nC(+1.83 %), 15.55 nC(+1.77 %), 15.51 nC(+1.51 %), 15.42 nC(+0.92 %), 15.39 nC(+0.72 %) respectively. When it was (depth of $D_{max}$ / applicator / pure lead), the relative value(scattering ratio) was 16.70 nC(-10.87 %), 16.84 nC(-10.12 %), 16.72 nC(-10.78 %), 16.88 nC(-9.93 %), 16.90 nC(-9.82 %) respectively. When it was (depth of $D_{max}$ / applicator / alloy lead), the relative value(scattering ratio) was 16.83 nC(-10.19 %), 17.12 nC(-8.64 %), 16.89 nC(-9.87 %), 16.77 nC(-10.51 %), 16.52 nC(-11.85 %) respectively. When it was (depth of $D_{max}$ / phantom / pure lead), the relative value(scattering ratio) was 17.41 nC(-7.10 %), 17.45 nC(-6.88 %), 17.34 nC(-7.47 %), 17.42 nC(-7.04 %), 17.25 nC(-7.95 %) respectively. When it was (depth of $D_{max}$ / phantom / alloy lead), the relative value(scattering ratio) was 17.45 nC(-6.88 %), 17.44 nC(-6.94 %), 17.47 nC(-6.78 %), 17.43 nC(-6.99 %), 17.35 nC(-7.42 %) respectively. Conclusions: When performing electron therapy using a shielding block, the block position should be inserted applicator rather than the patient's body surface. The block thickness should be made to the minimum appropriate shielding thickness of each corresponding using energy. Also it is useful that the treatment should be performed considering the influence of scattering dose varying with distance from the edge of block.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.41-48
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• 2019

Soil compaction is one of the most important activities in the area of civil works, including road construction, airport construction, port construction and backfilling construction of structures. Soil compaction, particularly in road construction, can be categorized into subgrade compaction and roadbed compaction, and is significant work that when done poorly can serve as a factor causing poor construction due to a lack of compaction. Currently, there are many different types of compaction tests, and the plate bearing test and the unit weight of soil test based on the sand cone method are commonly used to measure the degree of compaction, but many other methods are under development as it is difficult to secure economic efficiency. For the purpose of this research, a portable penetration meter called the Free-Fall Penetration Test (FFPT) was developed and manufactured. In this study, a homogeneous sample was obtained from the construction site and soil was classified through a sieve analysis test in order to perform grain size analysis and a specific gravity test for an indoor test. The principle of FFPT is that the penetration needle installed at the tip of an object put into free fall using gravity is used to measure the depth of penetration into the road surface after subgrade or roadbed compaction has been completed; the degree of compaction is obtained through the unit weight of soil test according to the sand cone method and the relationship between the degree of compaction and the depth of the penetration needle is verified. The maximum allowable grain size of soil is 2.36 mm. For $A_1$ compaction, a trend line was developed using the result of the test performed from a drop height of 10 cm, and coefficient of determination of the trend line was $R^2=0.8677$, while for $D_2$ compaction, coefficient of determination of the trend line was $R^2=0.9815$ when testing at a drop height of 20 cm. Free fall test was carried out with the drop height adjusted from 10 cm to 50 cm at increments of 10 cm. This study intends to compare and analyze the correlation between the degree of compaction obtained from the unit weight of soil test based on the sand cone method and the depth of penetration of the penetration needle obtained from the FFPT meter. As such, it is expected that a portable penetration tester will make it easy to test the degree of compaction at many construction sites, and will lead to a reduction in time, equipment, and manpower which are the disadvantages of the current degree of compaction test, ultimately contributing to accurate and simple measurements of the degree of compaction as well as greater economic feasibility.

• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.7-21
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• 1979

This investigation was to analyse normal protrusive and lateral condylar pantographic records written on the sagittal plane and to study components of Fisher's angle and their interrelations. The purpose of this study was limited to (1) discussing the significance of sagittal pantographic record in diagnosis of occlusal disease and(2) basing for reasoning validity of measuring Fisher's angle which has been reported so far. As a result followings were concluded. 1. In each protrusive and lateral condylar movement path, five complicate factors such as initial straightness, distributed simple sigmoid type, simple curvature, initial tiny protruding convexity and tiny repeated sigmoid patterns were noted. Generally each condylar movement path was composed of two to three of these factors. 2. The distribution of positional interrelations of protrusive and lateral condylar paths could be divided into five categories; (a) protrusive-upper, (b) completely coinciding, (c) partially initial coinciding, (d) partially inverted crossing, and (e) completely inverting. Among these, protrusive path-upper positioned condyles were prevailed (79.2%). 3. The distribution of interrelations of protrusive and lateral condylar paths could be devided into five categories according to their distances in the course of movement. Among these, opening (95.8%) and paralleling (66.7%) were prevailing. 4. The involved number of characteristic heterogenous patterns of five categories in protrusive and lateral condylar movement recording relations at one simultaneous recordings was limited to three. However, in case of homogeneous patterns were repeated, usually three to four were included. 5. The maximum distance between protrusive and lateral condylar paths was 1.45mm at the location of 4mm advanced position from centric relation point and 3.90mm at the location of protrusive movement terminal. 6. It seemed to be that ,pantographic records should be consulted other clinical symptoms in order to make certain occlusion diagnosis. 7. At the present moment of investigation, expressing Fisher's angle as a degree revealed a lack due to inherent complexity of protrusive and lateral condylar movement paths. 8. The typical pattern of protrusive and lateral condylar paths written on a pantographic sagittal plate might be described as follows; (a) protrusive condylar path should be positioned upwardly, (b) both mainly be simple curvature, (c) interrelations mainly be opening or paralleling. 9. The mean amounts of separation between protrusive and lateral condylar movement path were $0.75{\pm}0.46$ at 4mm advanced location from centric relation and $1.74{\pm}0.64mm$ at the location of protrusive path terminal.

• Journal of fish pathology
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• v.10 no.2
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• pp.75-86
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• 1997

Solid phase enzyme linked immunosorbent assay (ELISA) was developed to detect the whole cells of Edwardsiella tarda from infected tissues of flounder. Cross-reaction test was performed by ELISA against fish pathogens such as A. hydrophila ATCC7966. V. anguillarum HYUFP5001, Y, ruckeri 11-4, E. ictaluri and Streptococcus sp. NG8206. Rabbit anti-E, tarda Edk-2 sera highly cross-reacted with A. hydrophila ATCC7966 and V. anguillarum HUFP5001. However, the cross-reaction was removed by using the anti-serum pre-adsorbed with A, hydrophila ATCC7966 FKC. The intra-species cross-reaction among E. tarda isolates was very high. ELISA with the whole cell antigens present in tissue homogenate appeared with highly decreased sensitivity, presumably by the co-coating of lipid or proteins in tissues. Thus, it would be necessary to use the infected tissue homogenates diluted more than 100 times with PBS for diagnosis. Interestingly, compared with the using of FKC antigen, the direct detection of viable cells in tissue homogenate showed more sensitive results with detection limit of $1{\times}10^3$ cells/ml in buffer or diluted tissue homogenate. Consequently, the ELISA method developed in this study was specific, rapid and sensitive for diagnosing edwardsiellosis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.263-270
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• 1982

In an attempt to evaluate the nutritional quality of seaweed protein, the effects of heat treatment on the in vitro digestibility and trypsin inhibitor content in seaweed were determined. In this study, the nitrogen-to-protein conversion factors were also calculated on the basis of quantitative amino acid data. The results are as follows : 1. The in vitro protein digestbilty of red seaweeds (P. teoera anc P. suborbiculata) were ranged from 78.5 to 82.2, and green seawerd (E. linza) and brown seaweeds showed value under 80 in vitro digestibility. In general, trypsin inhibitor contents in brown seaweed were higher (0.33-0.54 mg/g) than those of red seaweeds (0.26-0.39 mg/g). And it is noted that the lowest trypsin inhibitor content was shown in green seaweed (E. linza) in spite of lowest in spite digestibility (78.5). 2. The in vitro protein digestibility of sun dried laver (P. tenera) was increased with cooling time (microwave heating), but it was not significant. Hot plate cooking raised the in vitro digestibility from 81. 1 to 84.5. The influence pot cooking time on trypsin inhibitor content was inversely proportional to in vitro digestibility. 3. Computed nitrogen factor, based on amino acid content (Factor method) and Kjeldahl nitrogen content (Kjeldahl mettled), were 5.83 (H. fusiforme)- 6.52 (P. tencra) as Factor method and 5.40 (U. pinnatifida)-6.29 (P. tenera) as Kjeldahl method. Individual value for each nitrogen conversion factor differed by species, especially in brown seaweeds. The best estimate of the protein content of seaweed can be calculated, from multiplying the summed amino acid content by conversion factor (Factor method).

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.81.2-81.2
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• 2012

To fabricate a metal mold for injection molding, hot-embossing and imprinting process, mechanical machining, electro discharge machining (EDM), electrochemical machining (ECM), laser process and wet etching ($FeCl_3$ process) have been widely used. However it is hard to get precise structure with these processes. Electrochemical etching has been also employed to fabricate a micro structure in metal mold. A through mask electrochemical micro machining (TMEMM) is one of the electrochemical etching processes which can obtain finely precise structure. In this process, many parameters such as current density, process time, temperature of electrolyte and distance between electrodes should be controlled. Therefore, it is difficult to predict the result because it has low reliability and reproducibility. To improve it, we investigated this process numerically and experimentally. To search the relation between processing parameters and the results, we used finite element simulation and the commercial finite element method (FEM) software ANSYS was used to analyze the electric field. In this study, it was supposed that the anodic dissolution process is predicted depending on the current density which is one of major parameters with finite element method. In experiment, we used stainless steel (SS304) substrate with various sized square and circular array patterns as an anode and copper (Cu) plate as a cathode. A mixture of $H_2SO_4$, $H_3PO_4$ and DIW was used as an electrolyte. After electrochemical etching process, we compared the results of experiment and simulation. As a result, we got the current distribution in the electrolyte and line profile of current density of the patterns from simulation. And etching profile and surface morphologies were characterized by 3D-profiler(${\mu}$-surf, Nanofocus, Germany) and FE-SEM(S-4800, Hitachi, Japan) measurement. From comparison of these data, it was confirmed that current distribution and line profile of the patterns from simulation are similar to surface morphology and etching profile of the sample from the process, respectively. Then we concluded that current density is more concentrated at the edge of pattern and the depth of etched area is proportional to current density.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.2
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• pp.84-96
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• 2007

The purpose of this study was to select herbaceous plants that can be used for presenting various views and biodiversity on the extensive rooftop greening. Experiment plots were constructed in July 2005 on the rooftop of the Administration Building in the Seoul Women's University. For this experiment, planters were used to design rooftop greening. The size of a planter is 500mm${\times}$500mm${\times}$100mm and each planter has the water storage plate in the lower part of it. The soil was constructed by mixing pearlite, vermiculite, cocopeat, and leaf mold in the ratio of 6 : 2 : 1 : 1. The plot was divided into the watered plot and the dry plot. Since each plot was constructed 2 times, finally 4 planters were constructed in total. One hundred species were used for the experiment and 9 plants per species were planted in each planter. Plants were organized according to types of plants and the experiment used 86 native herbaceous plants, 6 herbs, and 8 foreign plants. The plots were monitored once a month, from July to November 2005. The length and width of plants were tape-measured and covering rate was calculated by CAD program. "SPSS 10.1" was used for a statistical analysis. The result showed no significant difference between the watered plots and the dry plots. In cases of some plants, there were statistically significant differences between the watered planter and dry planter such as follows : Astilbe chinensis and Polygonatum odoratum which are shade plants were measured as the highest value on the watered pots, and Aquilegia buergeriana, Chrysanthemum zawadskii, Calendula arvensis and Gypsophila cerastioides D.Don which are sunny plants were measured as the highest value on the dry plots. According to the final analysis of the data collected and observed for growth condition during the first year of the research, 51 species including Prunella vulgaris var. lilacina and Veronica linaiaefolia in native herbaceous plant, 5 species with Lavandula angustifolia in herbs, and 3 species with Lantana camara and Muscari armeniacum in foreign plants showed the highest growth condition. In conclusion, it is suggested that various plants including sedums could be effectively used for extensive rooftop greening to improve landscape(a view) of the rooftop and increase ecological values.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.46-46
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• 2019

The experiments were performed in the Jinan (elevation: 300 meters above sea level), Jeollabuk-do. Seedlings (n = 63 per $3.3m^2$) of ginseng cultivar (Cheonpung, Yeonpung) were planted on April 10, 2015. Shading material of plastic film house was blue-white film. Before the Planting seedling, silicate (3 kg/10 a) or chitosan (40 kg/10 a) was fertilized and foliar sprayed on the leaves 1000 times dilution solution once a month from May to September every year. The growth results of 5-year old ginseng surveyed in 2018 are as follows. The average air temperature in the plastic film house was the highest at $26.6^{\circ}C$ and $26.5^{\circ}C$ in July and August, respectively, and the highest temperature was $40.5^{\circ}C$ in July. The maximum daily temperature of $35^{\circ}C$ or more was 30 days, with the average soil temperature being $24.9^{\circ}C$ in August. The chemical properties of the test soil are as follows. pH was 6.4~6.9 level and EC was 0.35~0.46 dS/m. The organic matter content was 33.5~41.4 g/kg, and available-P content was 251.9~306.8 mg/kg. Exchangeable cations contents, such as K, Ca and Mg were all the appropriate ranges. The soil microbial density surveyed by the dilution plate method was 10~50 times higher than that of control (Non-treatment) and actinomycete density was 3~6 times higher. Pathogens of the genus Fusarium by Metagenome analysis decreased 91.3% and 68.2% respectively in the foliar sprayed of chitosan and soluble-silicate. The light intensity (PAR) in the blue-white film plastic film house gradually increased until July and then decereased, with the average of light intensity in March-October was $120.3umol/m^2/s$. The growth of aerial parts such as plant height and stem length was better than non-sprayed group in silicate or chitosan treatments and Yeonpung cultivar was superior to the Cheonpung cultivar. The SPAD value was higher in Yeonpung cultivar foliar sprayed with soluble-silicate. The growth of underground parts such as root length and taproot length were better in chitosan and soluble-silicate treatment than control, especially in Yeonpung cultivar foliar sprayed with chitosan was good in taproot length and taproot diameter, and fresh weight of root was 60.1 g. Ginsenoside contents were 24.9 mg/g and 22.4 mg/g, in the Cheonpung cultivar foliar sprayed with soluble-silicate or chitosan respectively, 28% and 15% higher than control (19.5 mg/g). The incidence of disease by Alteraria panax and Botrytis cinerea was 3~9% and 4~9%, respectively. High temperature damage rate was 3~5%.