• Journal of the Korean Chemical Society
• /
• v.37 no.3
• /
• pp.327-333
• /
• 1993

A method was developed for the determination of trace elements in seawater by precipitate flotation preconcentration and subsequent flame atomic absorption detection. In order to quantitatively coprecipitate trace ions such as Cd(II), CuI(II), Fe(III), Mn(II), Pb(II) and Pd(II), 2.0 ml of 1.0M cerium(III) solution was added to 1.0l of seawater and the pH was adjusted to 9.5 with 5.0 M sodium hydroxide solution while stirring with a magnetic stirrer. The precipitate was floated with the aid of surfactant solution (1.0 ml of 0.3% sodium oleate) by bubbling nitrogen gas through a porous (No. 4) fritted glass disk. The floats was collected in a small Erlenmeyer flask by suction. The washed precipitate was dissolved in 8.0 M nitric acid and marked with deionized water in the volumetric flask of 10.0 ml. The analyte was determined by measuring the atomic absorbances in 100-fold concentrated solution. Above all analytes in Kangnung (East Sea) and Kanghwado (West Sea) sea waters were found to be under the detection limit of this method. The recoveries of over 92% for all analytes spiked into seawater samples showed that this method was applicable to the analysis of real seawater.

• Journal of Korean Medicine Rehabilitation
• /
• v.28 no.4
• /
• pp.33-41
• /
• 2018

Objectives The purpose of this study is to analyze the effects of Korean Medicine treatment on lumbar disc herniation (LDH) and predictive factors associated with disc resorption by magnetic resonance imaging (MRI). Methods A retrospective study was carried out in 79 lumbar disc herniation patients who had visited Haeundae Jaseng Hospital of Korean Medicine. Patients' diagnosis was based on MRI. MRI was performed on two or more occasions and patients were received Korean Medicine treatment within the period. The volume of each herniated disc was measured three-dimensionally and patient characteristics, interval between MRIs, herniated disc level, disc herniation type, disc migration, intactness of posterior longitudinal ligament (PLL), initial volume of herniated disc, modic change, disc resorption rate were statistically analyzed. Results The mean volumes of herniated discs before Korean Medicine treatment and after Korean Medicine treatment were $1,547.81{\pm}598.15mm^3$ and $947.06{\pm}335.28mm^3$, respectively. The mean resorption rate was $35.7{\pm}16.3%$. Disc extent, intactness of PLL and initial volume of herniated discs were significantly correlated with resorption rate (p=0.003, p=0.001 and p=0.024, respectively). Conclusions Korean Medicine treatment is an effective conservative treatment for lumbar disc herniation. Factors such as disc migration, intactness of PLL, initial volume of herniated disc have a significant association with disc resorption rate.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.592-592
• /
• 2016

국내에는 17,500여개의 농업용 저수지가 전국적으로 분포하고 있다. 국내 농업용 저수지는 대부분이 소규모이며, 연중 수량 변동이 심하고, 유역배율이 작아 태생적으로 수질오염에 취약한 구조로 되어 있다. 특히 농업용 저수지는 도시 근교나 농촌지역에 많이 위치하고 있어 유역 내 축산 농가나 미처리 생활하수에서 유래된 유기물 및 영양염류 유입에 의한 수질오염도가 높다. 저수지에 고농도로 유입되는 유기물, TN, TP를 처리하기 위하여 농어촌연구원과 수생태복원(주)에서는 공동으로 친환경 수처리시설인 생태융합형 접촉산화시스템을 개발하였다. 생태융합 접촉산화수로는 상부 식생과 수로 내의 섬유상 끈상 미생물 접촉재를 이용하여 오염수가 수로를 흐르면서 침전, 여과, 흡착, 산화, 흡수 등 물리학적, 화학적, 생물학적 원리를 이용하여 고농도의 유기물과 질소, 인을 제거하는 물리적, 생물학적 공정을 융복합 기술이다. 본 연구에서는 경기도 시흥시에 소재하고 있는 M 저수지에 현장 Test-bed를 구축하여 수질정화효율을 평가하였다. M 저수지는 유효저수지량이 약 23만톤에 해당하는 소규모 저수지로, 1941년도 준공된 아주 노후화된 저수지로 평균 수심이 2m 이하이고 연중 수질오염도가 높은 저수지이다. 매화저수지 수변에 설치된 생태융합형 접촉산화수로의 전체규모는 길이 8.6m, 폭 2m, 수심 2m에 해당하며, 끈상 미생물 메디아조 3개($2{\times}2{\times}6m^3$), 침전조 1개($2{\times}2{\times}2m^3$)로 구성되어 있다. 기타 부대 장치로는 끈상 메디아조에 산소공급을 위한 Air-mist(마이크로 버블 발생장치), 자동운전계기판, 유입펌프 등이 있다. 생태융합형 접촉산화수로의 처리 공정은 유입수${\rightarrow}$에어미스트${\rightarrow}$고속복합응집장치${\rightarrow}$융복합 산화조(3조)${\rightarrow}$침전조${\rightarrow}$방류로 구성되어 있다. 테스트 베드는 2015년 8월 말경에 구축 완료하였으며, 끈상 미생물 메디아조의 수질정화효율을 평가하기 위하여 9월부터 11월까지 총 7회 걸쳐 유입수와 유출수를 각각 조사하였다. 현장 측정항목인 수온, pH, EC, DO 등은 유입수 및 유출수간 큰 차이가 없었고, COD, SS, Chl-a, TP 등은 수처리시스템 초기 가동시에는 메디아에 미생물 부착율 저조로 유입수 및 유출수 수질농도에 큰 차이가 없었으나, 운영시간의 경과와 함께 메디아의 미생물 충진율이 높아짐에 따라 처리효율이 최대 SS 69.6%, Chl-a 89.3%, TP 89%까지 도달하는 것으로 나타났다. 생태융합 접촉산화수로는 부지 집약적인 컴팩트한 수처리 시설로서 현재 널리 이용되고 있는 인공습지를 대체할 수 있는 경제적인 시설로 판단된다.

• The korean journal of orthodontics
• /
• v.37 no.6
• /
• pp.391-399
• /
• 2007

Three-dimensional approaches for the diagnosis and analysis of the dentofacial area are becoming more popular in accordance with the development of cone-beam CT (CBCT). The purposes of this study were to evaluate the reliability of cephalometric measurements of lateral cephalograms generated from a CBCT image by making comparisons with the traditional digital lateral cephalogram, and to evaluate the possibility of the clinical application of CBCT generated cephalogram images. Methods: Twenty patients whose external auditory meatus could be identified in the CBCT image were selected, and both CBCT and digital cephalograms were taken. Differences between the measurements of both cephalograms were tested by paired t-test. Results: Among the 22 measurements used, only U1-FH, Mx6 to PTV, and maxillomandibular difference showed statistically significant differences between the CBCT generated cephalogram and the digital cephalogram. Conclusions: The results suggest that the CBCT generated cephalogram can be used for some cephalometric measurements not requiring porion, PTV, condylion as a landmark (SNA, SNB, U1 to SN, IMPA, interincisal angle, etc.).

• Progress in Medical Physics
• /
• v.20 no.4
• /
• pp.308-316
• /
• 2009

To achieve the accurate evaluation of given absorbed dose from output dose of linear accelerator photon beam through investigate the characteristics of LiF:Mg,Cu,P TLD powder. This experimental TL phosphor is performed with a commercial LiF:Mg,Cu,P powder (Supplied by PTW) and TL reader (LTM, France). The TLD was exposed to 6 MV X rays of linear accelerator photon beam with range 15 to 800 cGy in blind dose at two hospitals. The dose evaluation of TLD was through the experimental algorithms which were dose dependency, dose rate dependency, fading and powder weight dependency. The glow curve has shown the three peaks which are 110, 183 and 232 degrees of heating temperature and the main dosimetric peak showed highest TL response at 232 high temperature. In this experiments, the LiF:Mg,Cu,P phosphor has shown the 2.5 eV of electron trap energy with a second order. This experiments guided the dose evaluation accuracy is within 1% +2.58% of discrepancy. The TLD powder of LiF:Mg,Cu,P was analyzed to dosimetric characterists of electron captured energy and order by glow shape, and dose-TL response curve guided the accuracy within 1.0+2.58% of output dose discrepancy.

• Archives of design research
• /
• v.17 no.4
• /
• pp.241-250
• /
• 2004

In this research, the copper alloy plates C2200, C5210, C7701, C8113 were selected to make datum and to identify further usage of metal craft experimentation. For its experimentation, the general welding and TIG welding methods were researched; for 2nd experimentation, the Reticulation and Electroforming skill's differences in color and temperature were researched. With these methods 3 different kinds of works are introduced for sample studies. For this research, Dr. Lee, Dong-Woo who works in Poongsan Metal Co, supported 4 kinds of copper alloy metals. Which are Commercial bronze (Cu-Zn), Deoxidiged Copper(Cu-Sn-P), Nickel Silver (Cu-Ni-Zn), and White Bronze (Cu-Ni); they were applied partly and wholly by the method of Laminatin, Reticulation, Fusing, and Electroforming skills. In case of C2200, the brass, the A. C. TIG welding method is better under 2mm slight plate; the D.C. TIG welding is better upper 2mm plate; and 250~300$^{\circ}C$ is recommended for remain heat treatment. In case of C5210, not having Hydrogen in high temperature return period, doesn't need Oxygen in high temperature and hardening in comparative high temperature neither, it is good for welding. It contains Sn 2-9% ad P 0.03-0.4% generally; and in accordance with the growth rate of Sn contain amount, the harden temperature boundary become broad. In case of cold moment after welding, they are recommended that higher speed TIG welding, smaller melting site and less than 200$^{\circ}C$ for pre-heating temperature. In case of C7701, the 10-20% Ni, 15-30% Zn are widely used.. If it is upper 30% Zn, it become (${\alpha}+{\beta}$) system and adhesive power rate become lower, and the productivity become lower in low temperature but the productivity become higher in high temperature. Nickel Silver's resistance of electricity is well; and the heatproof and incorrodibility is good, too. Lastly, in case of C8113, good at persistence in salty and grind; high in strength of high temperature. In case of white brass, contain 10-30% Nickel and hardened in high temperature and become single phrase. For these reason, the crystallization particles easily become large, if the resistance become higher small amount of Pb, P, S separation rate become higher.

• Progress in Medical Physics
• /
• v.26 no.1
• /
• pp.12-17
• /
• 2015

The purpose of the Monte Carlo simulation study was to provide the optimized nozzle design to satisfy the beam conditions for biomedical researches in the Korean heavy-ion accelerator, RAON. The nozzle design was required to produce $C^{12}$ beam satisfying the three conditions; the maximum field size, the dose uniformity and the beam contamination. We employed the GEANT4 toolkit in Monte Carlo simulation to optimize the nozzle design. The beams for biomedical researches were required that the maximum field size should be more than $15{\times}15cm^2$, the dose uniformity was to be less than 3% and the level of beam contamination due to the scattered radiation from collimation systems was less than 5% of total dose. For the field size, we optimized the tilting angle of the circularly rotating beam controlled by a pair of dipole magnets at the most upstream of the user beam line unit and the thickness of the scatter plate located downstream of the dipole magnets. The values of beam scanning angle and the thickness of the scatter plate could be successfully optimized to be $0.5^{\circ}$ and 0.05 cm via this Monte Carlo simulation analysis. For the dose uniformity and the beam contamination, we introduced the new beam configuration technique by the combination of scanning and static beams. With the combination of a central static beam and a circularly rotating beam with the tilting angle of $0.5^{\circ}$ to beam axis, the dose uniformity could be established to be 1.1% in $15{\times}15cm^2$ sized maximum field. For the beam contamination, it was determined by the ratio of the absorbed doses delivered by $C^{12}$ ion and other particles. The level of the beam contamination could be achieved to be less than 2.5% of total dose in the region from 5 cm to 17 cm water equivalent depth in the combined beam configuration. Based on the results, we could establish the optimized nozzle design satisfying the beam conditions which were required for biomedical researches.

• Applied Microscopy
• /
• v.30 no.4
• /
• pp.357-365
• /
• 2000

Paneth cells have been suggested to contribute to the elimination of excess metals into the intestinal lumen. The purpose of this study wat to investigate the changes of the zinc pools in rats subjected to functional loading with zinc salt by mean of both light and electron microscopical autometallography (AMG). Wistar rats 4 were administrated with zinc chloride (20 mg/kg body weight) intraperitoneally dissolved in 1 ml distilled water. The control group received 1 ml saline IP. After further one hour the animals were transcardially perfused with 0.4% sodium sulphide dissolved in 0.1 M PB fellowed by 3% glutaraldehyde solution for 10 minutes. Pieces of ileum were frozen with solid $CO_2$ and sectioned on a cryostat. The sections $(20{\mu}m)$ were autometallographically developed. Sections selected for EM were reembedded on top of a blank Epon block, from which ultrathin sections (100 nm) were cut. The ultrathin sections were double stained with uranyl acetate (30 min) and lead citrate (5 min), then examined under electron microscope. Studies of comparable sections from control and zinc loaded animals with the AMG selenium method gave quite different results. The control animals demonstrated a weakly positive staining in the cytoplasm of the Paneth cells. In the electron microscope the AMG silver grains were found to be located in the cytoplasm, while the electron dense secretary granules and other cell organelles were void of staining. Few AMG grains were located at the apical surface of the Paneth cells. In sections from zinc loaded rats, the AMG grains were seen in abundance in the lumen of the Lieberkuhn crypts at light microscopic levels. At EM levels the zinc revealing silver grains were located in the cytoplasm as in the controls, but much more AMG grains were shifted into the secretary granules. Furthermore, profound AMG grains were found in the lumen of the crypts and surrounding vessels. And a few grains were seen in the endothelium. The AMG technique demonstrated a pattern of AMG grains in the Paneth cells that strongly suggests a transport of zinc ions through these cells.

• The korean journal of orthodontics
• /
• v.25 no.4
• /
• pp.403-414
• /
• 1995

The purpose of this study was to investigate the histologic changes in mandibular periodontium during overbite closure for openbite treatment by continuous arch wires and anterior vertical elastics. Two female monkey(Macaca nemestrina) with permanent dentition were used. Posterior bite block was fixed to each of their maxillae, which made the animal temporary anterior openbite as well as stabilized the whole maxillary anchorage. In each mandible, all the teeth except the second molars which had been extracted, were prepared for cast crowns. 018 inch Standard brackets were welded on these crowns. After cementation, two types of the $016{\times}022$ inch continuous arch wires, the plain ideal arch to the control animal and the MEAW(multiloop edgewise archwire) to the other experimental one were inserted. Then anterior vertical elastics were applied for two weeks. The overbite depth changes in the monkeys and histologic examinations of the mandibular periodontiums suggested the following conclusions. 1. During two weeks of the experimental period, the overbite increased + 0.3 mm in the control and + 1.3 mm in the experimental one. 2. In both the control and the experimental animal, histologic examinations showed that incisors, canines and first premolars were subject to extrusive force and the rest of posteriors were subject to intrusive one. 3. In periodontiums of the extruded incisors of the experimental one, reorientation of the periodontal fiber structures reflected the direction of force and the alveolar bone surfaces including apical and crestal areas which had been subject to tension, were the front of new bone formation. 4. In periodontiums of the extruded incisors of the experimental one, neither excessive hyalinization nor gross root resorption was observed. 5. Alveolar bone remodeling of anteriors and posteriors was more remarkable in the experimental one than the control.

• Economic and Environmental Geology
• /
• v.53 no.1
• /
• pp.45-69
• /
• 2020

In Danyang area, various geological structures as well as various lithology and strata are well developed, which are useful for studying paleo-environment and structural movements, and also typical karst landforms, wethering landforms and river landforms. If geologically and geomorphologically valuable resources are used in terms of geotourim perspective, it is expected that revitalization of regional economy through diversification of attracting factors and employment creation of local people. Danyang has many excellent geological resources for geological field trip, they can greatly contribute to the development of geology such as expanding the base of geology and cultivating successive generations. In this study, we have evaluated newly discovered sites and previously excavated resources based on academical and educational values. By using these geological and geomorphological resources, we suggest three geotrail courses as follows. First, Geo-trail A is mainly focused on geological structures (Route A: Jeong Hwan Route), where we can learn geological deformation and movement through various brittle and ductile deformation structures. Second, Geo-trail B is mainly focused on stratigraphic importance (Route B: Soon-Bok Route), which emphasizes on various rocks, strata and contact relationship. Third, Geo-trail C is mainly focused on geomorphological landforms and landscapes (Route C: Satgat Route), which provide information about different geomorphological landforms and the interaction between different geological agents. In order to operate these geotrail courses efficiently, installation of explanation boards and view points, cultivate local commentators, and visitor centers and experience programs should be properly prepared together.