• Title/Summary/Keyword: 부착판

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Nuclear SSU and Plastid rbcL Genes and Ultrastructure of Mallomonas caudata (Synurophyceae) from Korea (한국산 Mallomonas caudata (Synurophyceae)의 미세구조, 핵 SSU 그리고 색소체 rbcL 유전자)

  • Kim, Han-Soon;Shin, Woong-Ghi;Boo, Sung-Min
    • Korean Journal of Ecology and Environment
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    • v.40 no.3
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    • pp.387-394
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    • 2007
  • Despite geographic barriers such as oceans, many freshwater algal species inhabit different continents of the world. A unicellular freshwater alga, Mallomonas caudeata, commonly occurring in Asia, Europe, and America of the northern Hemisphere, is closely related to human life such as monitoring blooms and defecting changes in climates. In order to demonstrate its occurrence in Korea and to infer its phylogeny, we sequenced nuclear SSU and plastid rbcL genes from isolates collected in six different reservoirs. We have also investigated transmission electron microscopy of the Korean isolates. SSU sequences of the species from Korea and USA were almost identical, having pair-wise divergences of 0.06% in SSU and 0.45% in rbcL. Both gene trees revealed that the species was clearly separated from other species of the genus, while the genus was not monophyletic. Rhizoplasts are composed of microfibrils organised in striated rootlets attached to the multilayered plate of basal bodies and arranged on the surface of the nucleus at their distal ends. The rhizoplast constitutes a basal body-nucleus connector similar to that of typical Synurophyceas. The results that Mallomonas was not supported by both SSU and rbeL data sets require a further study with additional taxon sampling.

Manufacture of Daily Check Device and Efficiency Evaluation for Daily Q.A (일일 정도관리를 위한 Daily Check Device의 제작 및 효율성 평가)

  • Kim Chan-Yong;Jae Young-Wan;Park Heung-Deuk;Lee Jae-Hee
    • The Journal of Korean Society for Radiation Therapy
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    • v.17 no.2
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    • pp.105-111
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    • 2005
  • Purpose : Daily Q.A is the important step which must be preceded in a radiation treatment. Specially, radiation output measurement and laser alignment, SSD indicator related to a patient set-up recurrence must be confirmed for a reasonable radiation treatment. Daily Q.A proceeds correctness and a prompt way, and needs an objective measurement basis. Manufacture of the device which can facilitate confirmation of output measurement and appliances check at one time was requested. Materials and Methods : Produced the phantom formal daily check device which can confirm a lot of appliances check (output measurement and laser alignment. field size, SSD indicator) with one time of set up at a time, and measurement observed a linear accelerator (4 machine) for four months and evaluated efficiency. Results : We were able to confirm an laser alignment, field size, SSD indicator check at the same time, and out put measurement was possible with the same set up, so daily Q.A time was reduced, and we were able to confirm an objective basis about each item measurement. As a result of having measured for four months, output measurement within ${\pm}2%$, and measured laser alignment, field size, SSD indicator in range within ${\pm}1mm$. Conclusion : We can enforce output measurement and appliances check conveniently, and time was reduced and was able to raise efficiency of business. We were able to bring a cost reduction by substitution expensive commercialized equipment. Further It is necessary to makes a product as strong and slight materials, and improve convenience of use.

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Dose Characteristics of Total-Skin Electron-Beam Irradiation with Six-Dual Electron Fields (Six-Dual 전자선 조사면에 의한 전신 피부 조사의 선량 특성)

  • Choi, Tae-Jin;Kim, Jin-Hee;Kim, Ok-Bae
    • Radiation Oncology Journal
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    • v.16 no.3
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    • pp.337-345
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    • 1998
  • Purpose : To obtain the uniform dose at limited depth to entire surface of the body, the dose characteristics of degraded electron beam of the large target-skin distance and the dose distribution of the six-dual electron fields were investigated Materials and Method : The experimental dose distributions included the depth dose curve, spatial dose and attenuated electron beam were determined with 300 cm of target-skin distance (TSD) and full collimator size (35*35 $cm^2$ on TSD 100 cm) in 4 MeV electron beam energy. Actual collimated field size of 105 cm * 105 cm at the distance of 300 cm could include entire hemibody. A patient was standing on step board with hands up and holding the pole to stabilize his/her positions for the six-dual fields technique. As a scatter-degrader, 0.5 cm of acrylic plate was inserted at 20 cm from the body surface on the electron beam path to induce ray scattering and to increase the skin dose. Results : The full width at half maximum(FWHM) of dose profile was 130 cm in large field of 105*105 $cm^2$ The width of $100\pm10\%$ of the resultant dose from two adjacent fields which were separated at 25 cm from field edge for obtaining the dose unifomity was extended to 186 cm. The depth of maximum dose lies at 5 mm and the 80$\%$ depth dose lies between 7 and 8 mm for the degraded electron beam by using the 0.5 cm thickness of acrylic absorber. Total skin electron beam irradiation (TSEBI) was carried out using the six dual fields has been developed at Stanford University. The dose distribution in TSEBI showed relatively uniform around the flat region of skin except the protruding and deeply curvatured portion of the body, which showed excess of dose at the former and less dose at the latter. Conclusion : The percent depth dose, profile curves and superimposed dose distribution were investigated using the degraded electron beam through the beam absorber. The dose distribution obtained by experiments of TSEBI showed within$\pm10\%$ difference except the protruding area of skin which needs a shield and deeply curvatured region of skin which needs boosting dose.

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Development and Experimental Performance Evaluation of Steel Composite Girder by Turn Over Process (단면회전방법을 적용한 강합성 소수주거더 개발 및 실험적 성능 평가)

  • Kim, Sung Jae;Yi, Na Hyun;Kim, Sung Bae;Kim, Jang-Ho Jay
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.5A
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    • pp.407-415
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    • 2010
  • In Korea, more than 90% of the total number of steel bridges built for 40~70 m span length is a steel box-girder bridge type. A steel box-girder bridge is suitable for long span or curved bridges with outstanding flexural and torsional rigidity as well as good constructability and safety. However, a steel box-girder bridge is uneconomical, requiring many secondary members and workmanship such as stiffeners and ribs requiring welding attachments to flanges or webs. Therefore, in US and Japan, a plate girder bridge, which is relatively cheap and easy to construct is generally used. One type of the plate girder bridge is the two- or three-main girder plate bridge, which is a composite plate girder bridge that minimizes the number of required main girders by increasing the distance between the adjacent girders. Also, for the simplification of girder section, the stiffener which requires attachment to the web is not required. The two-main steel girder plate bridge is a representative type of plate girder bridges, which is suitable for bridges with 10 m effective width and has been developed in the early 1960s in France. To ensure greater safety of two- or three-main girder plate bridges, a larger steel section is used in the bridge domestically than in Europe or Japan. Also, the total number of two- or three-main girder plate bridge constructed in Korea is significantly less than the steel box girder bridge due to a lack of designers' familiarity with more complex design detailing of the bridge compare to that of a steel box girder bridge design. In this study, a new construction method called Turn Over method is proposed to minimize the steel section size used in a two- or three-main girder plate bridge by applying prestressing force to the member using confining concrete section's weight to reduce construction cost. Also, a full scale 20 m Turn Over girder specimen and a Turn Over girder bridge specimen were tested to evaluate constructability and structural safety of the members constructed using Turn Over process.

The Evaluation of Radiation Dose to Embryo/Fetus and the Design of Shielding in the Treatment of Brain Tumors (임산부의 전뇌 방사선 치료에 있어서의 태아의 방사선량 측정 및 차폐 구조의 설계)

  • Cho, Woong;Huh, Soon-Nyung;Chie, Eui-Kyu;Ha, Sung-Whan;Park, Yang-Gyun;Park, Jong-Min;Park, Suk-Won
    • Journal of Radiation Protection and Research
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    • v.31 no.4
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    • pp.203-210
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    • 2006
  • Purpose : To estimate the dose to the embryo/fetus of a pregnant patient with brain tumors, and to design an shielding device to keep the embryo/fetus dose under acceptable levels Materials and Methods : A shielding wall with the dimension of 1.55 m height, 0.9 m width, and 30 m thickness is fabricated with 4 trolleys under the wall. It is placed between a Patient and the treatment head of a linear accelerator to attenuate the leakage radiation effectively from the treatment head, and is placed 1 cm below the lower margin of the treatment field in order to minimize the dose to a patient from the treatment head. An anti-patient scattering neck supporters with 2 cm thick Cerrobend metal is designed to minimize the scattered radiation from the treatment fields, and it is divided into 2 section. They are installed around the patient neck by attach from right and left sides. A shielding bridge for anti-room scattered radiation is utilized to place 2 sheets of 3 mm lead plates above the abdomen to setup three detectors under the lead sheets. Humanoid phantom is irradiated with the same treatment parameters, and with and without shielding devices using TLD, and ionization chambers with and without a build-up cap. Results : The dose to the embryo/fetus without shielding was 3.20, 3.21, 1.44, 0.90 cGy at off-field distances of 30, 40, 50, and 60 cm. With shielding, the dose to embryo/fetus was reduced to 0.88, 0.60, 0.35, 0.25 cGy, and the ratio of the shielding effect varied from 70% to 80%. TLD results were 1.8, 1.2, 0.8, 1.2, and 0.8 cGy. The dose measured by the survey meter was 10.9 mR/h at the patient's surface of abdomen. The dose to the embryo/fetus was estimated to be about 1 cGy during the entire treatment. Conclusion : According to the AAPM Report No 50 regarding the dose limit of the embryo/fetus during the pregnancy, the dose to the embryo/fetus with little risk is less than 5 cGy. Our measurements satisfy the recommended values. Our shielding technique was proven to be acceptable.

A Study on Optimal Packing Volume of Media in Swirl Flow Biological Fluidized Bed (선회류 생물학적 유동상의 최적 메디아 충전량에 관한 연구)

  • Choi, Doo-Hyoung;Kim, Hwan-Gi
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.2
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    • pp.331-340
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    • 2000
  • The existing two-phase biological fluidized bed has some problems such as limit of oxygen transfer and blockade of fluidized distributor. In this study, three-phase swirl flow biological fluidized bed has designed to solve the problems and to investigate its running characteristics. TOC of influent synthetic wastewater was approximately $70mg/{\ell}$. HRT of reactor was 1.6 hours. Mean particle size of sand, as packing media, was 0.397mm and packing volume was varied from $200m{\ell}/{\ell}$ to $600m{\ell}/{\ell}$ by stages in the bed. The amount of biomass and effluent water quality was throughly investigated in the bed. Showing experiment results from the above conditions, it was possible to solve the problems of existing fluidized bed and to keep DO of $3mg/{\ell}$ or more. And it was also TOC removal rate of 91 to 94 %, MLVSS of 2,360 to $3,860mg/{\ell}$, MLVSS per g-media of 8.4 to 17.3 mg/g, F/M ratio of 0.59 to $1.04kg-TOC/kg-MLVSS{\cdot}day$, biofilm thickness of $35{\sim}71{\mu}m$ and sludge productivity of 1.03 to $2.35kg-SS/m^3{\cdot}day$. Optimal conditions in this experimental were as follows.; those were biofilm thickness of approximately $54{\mu}m$. MLVSS per g-media of 13 mg and media packing volume of 350 to $400m{\ell}/{\ell}$ when F/M ratio was low, treatment efficiency was high and sludge productivity was low. Showing the media with optics microscope in this optimal condition, attached microbes such as Epistylis sp. were observed. From SEM photographs, it showed that Coccus adhere to and grow on the media surface.

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AN EXPERIMENTAL STUDY ON THE FATIGUE CHARACTERISTICS OF ORTHODONTIC BRACKETS BONDED TO ENAMEL (교정용 브라켓 접착부의 피로특성에 관한 실험적 연구)

  • Choi, Hae-Woon;Kim, Jeong-Gee
    • The korean journal of orthodontics
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    • v.25 no.1 s.48
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    • pp.55-72
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    • 1995
  • The purpose of this study is to evaluate the effects of mechanical and thermal fatigue on the shear bond strength(SBS) in orthodontic brackets bonded to human premolars with chemically cured adhesive(Mono-$Lok^2$, Rocky Mountain Orthodontics). Two types of metal brackets (Ormesh, Microloc) and three types of ceramic brackets (Fascination, Starfire, Transcend 2000) were used in this study. The $10^6$ loadcycles of $|7.4{\times}10{^2}sin2{\pi}ft|g{\cdot}cm$ and the 1,000 thermocycles of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ baths were acturated as mechanical and thermal fatigue stress, and SBS were measured after each fatigue test. The fracture sites were examined by stereoscope and scanning electron microscope. The results obtained were summarized as follows, 1. In static shear bond test, Fascination brackets showed the maximum SBS($20.78\pm3.45$ MPa) and Microloc brackets showed the minimum SBS($14.88\pm3.10$ MPa). Fascination and Starfire brackets showed significantly greater SBS than Microloc brackets(P<0.05). 2. In mechanical fatigue test, Fascination brackets showed the maximum SBS ($20.19\pm3.45$ MPa) and Starfire brackets showed the minimum SBS($9.10\pm8.33$ MPa). The SBS or Transcend 2000 brackets(P<0.01) and Starfire brackets(P<0.05) significantly decreased after $10^6$ loadcycles. 3. In thermocycling test, Ormesh brackets showed the maximum SBS ($19.36\pm2.76$ MPa) and Starfire brackets showed the minimum SBS($11.94\pm6.86$ MPa). The SBS of Transcend 2000(P<0.01), Microloc and Starfire brackets(P<0.05) significantly decreased after $10^3$ thermocycles. 4. Failure sites of thermocycling groups were similar to those of static groups but after mechanical fatigue test, Ormesh and Transcend 2000 brackets failed at the bracket/resin interface and Microloc brackets failed within adhesive. Facination brackets failed at the enamel/resin interface irrespective of experimental condition.

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Development of Manual Multi-Leaf Collimator for Proton Therapy in National Cancer Center (국립암센터의 양성자 치료를 위한 수동형 다엽 콜리메이터 개발)

  • Lee, Nuri;Kim, Tae Yoon;Kang, Dong Yun;Choi, Jae Hyock;Jeong, Jong Hwi;Shin, Dongho;Lim, Young Kyung;Park, Jeonghoon;Kim, Tae Hyun;Lee, Se Byeong
    • Progress in Medical Physics
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    • v.26 no.4
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    • pp.250-257
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    • 2015
  • Multi-leaf collimator (MLC) systems are frequently used to deliver photon-based radiation, and allow conformal shaping of treatment beams. Many proton beam centers currently make use of aperture and snout systems, which involve use of a snout to shape and focus the proton beam, a brass aperture to modify field shape, and an acrylic compensator to modulate depth. However, it needs a lot of time and cost of preparing treatment, therefore, we developed the manual MLC for solving this problem. This study was carried out with the intent of designing an MLC system as an alternative to an aperture block system. Radio-activation and dose due to primary proton beam leakage and the presence of secondary neutrons were taken into account during these iterations. Analytical calculations were used to study the effects of leaf material on activation. We have fabricated tray model for adoption with a wobbling snout ($30{\times}40cm^2$) system which used uniform scanning beam. We designed the manual MLC and tray and can reduce the cost and time for treatment. After leakage test of new tray, we upgrade the tray with brass and made the safety tool. First, we have tested the radio-activation with usually brass and new brass for new manual MLC. It shows similar behavior and decay trend. In addition, we have measured the leakage test of a gantry with new tray and MLC tray, while we exposed the high energy with full modulation process on film dosimetry. The radiation leakage is less than 1%. From these results, we have developed the design of the tray and upgrade for safety. Through the radio-activation behavior, we figure out the proton beam leakage level of safety, where there detects the secondary particle, including neutron. After developing new design of the tray, it will be able to reduce the time and cost of proton treatment. Finally, we have applied in clinic test with original brass aperture and manual MLC and calculated the gamma index, 99.74% between them.

Deterioration Diagnosis and Source Area of Rock Properties at the West Stone Pagoda, Gameunsaji Temple Site, Korea (감은사지 서탑의 풍화훼손도 진단 및 석재의 산지추정)

  • Lee Chan Hee;Lee Myeong Seong;Suh Mancheol;Choi Seok-Won;Kim Man Gap
    • Economic and Environmental Geology
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    • v.37 no.5
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    • pp.569-583
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    • 2004
  • The rock properties of the West pagoda in the Gameunsaji temple site are composed mainly of dark grey porphyritic granodiorite with medium grained equigranular texture and developed with small numerous dioritic xenoliths. These xenoliths occurred with small holes due to different weathering processes. As a weathering results, the rock properties of this pagoda occur wholly softened to physical hardness because of a complex result of petrological, meteorological and biological causes. Southeastern part of the pagoda deteriorated seriously that the surface of rock blocks showed partially exfoliations, fractures, open cavities in course of granular decomposition of minerals, sea water spray and crystallization of salt from the eastern coast. The Joint between blocks has small or large fracture cross each other, contaminated and corrupted for inserting with concrete, cement mortar, rock fragments and iron plates, and partially accelerated coloration and fractures. There are serious contamination materials of algae, fungus, lichen and bryophytes on the margin and the surface on the roof stone of the pagoda, so it'll require conservation treatment biochemically for releasing vegetation inhabiting on the surface and the discontinuous plane of the blocks because of adding the weathering activity of stones and growing weeds naturally by soil processing on the fissure zone. Consisting rock for the conservation and restoration of the pagoda would be careful choice of new rock properties and epoxy to reinforce for the deterioration surfaces. For the attenuation of secondary contamination and surface humidity, the possible conservation treatments are needed.

Analysis of the Inter- and Intra-treatment Isocenter Deviations in Pelvic Radiotherapy With Small Bowel Displacement System (Small Bowel Displacement System을 이용한 골반부 방사선조사에서 치료간 및 치료중 중심점 위치변동에 관한 분석)

  • Kim Moon Kyung;Kim Dae Yong;Ahn Yong Chan;Huh Seung Jae;Lim Do Hun;Shin Kyung Hwan;Lee Kyu Chan
    • Radiation Oncology Journal
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    • v.18 no.2
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    • pp.114-119
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    • 2000
  • Purpose : To evaluate the e지ent and frequency of the inter- and intra-treatment isocenter deviations of the whole pelvis radiation field in using small bowel displacement system (SBDS). Methods and Materials : Using electronic portal imaging device (EPID), 302 postero-anterior 232 lateral portal images were prospectively collected from 11 patients who received pelvic radiation therapy (7 with cervix cancer and 4 with rectal cancer). All patients were treated in prone position with SBDS under the lower abdomen. Five metallic fiducial markers were placed on the image detection unit for the recognition of the isocenter and magnification. After aligning the bony landmarks of the EPID images on those of the reference image, the deviations of the isocenter were measured in right-left (RL), cranio-caudal (CC), and PA directions. Results : The mean inter-treatment deviation of the isocenter in each RL, CC, and PA direction was 1.2 mm ($\pm$ 1.6 mm), 1.0 mm ($\pm$3.0 mm), and 0.9 mm ($\pm$4.4 mm), respectively. Inter-treatment isocenter deviations over 5 mm and 10 mm in RL, CC, and PA direction were 2, 12, 24$\%$, and 0, 0, 5$\%$, respectively. Maximal deviation was detected in PA direction, and was 11.5 mm. The mean intratreatment deviation of the isocenter in RL, CC, and PA direction was 0 mm ($\pm$0.9 mm), 0.1 mm ($\pm$ 1.9mm), and 0 mm ($\pm$1.6 mm), respectively. All intra-treatment isocenter deviations over 5 mm in each direction were 0, 1, 1$\pm$, respectively. Conclusions : As the greatest and the most frequent inter-treatment deviation of the isocenter was along the PA direction, it is recommended to put more generous safety margin toward the PA direction on the lateral fields if clinically acceptable in pelvic radiotherapy with SBDD.

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