• Progress in Medical Physics
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• v.15 no.1
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• pp.54-58
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• 2004

The aim of this study was to develop special birdcage resonators for small objects including the human wrist, hand and small animals, using 3T MRI/MRS. Before substantial development, different types of parameters were arranged, based on theoretical analysis, through lumped element transmission line theory. The primary analysis was peformed with a network analyzer (HP 4195A) and the final experimental analysis was carried out with 3T MRI (Medinus, Korea). The manufactured birdcage resonator is typically composed of 12-element structures to which a low-pass filter is fundamentally applied. The diameter and length of each element of the birdcage resonator were as follows: (1) diameter 12 cm, length of element 22 cm, (2) diameter 15 cm, length of element 22 cm, and (2) diameter 17 cm, length of element 25 cm. Copper tape with a width of 1 cm was used for the coils. MRI acquisition parameters were TR=500 ms, TE=17 ms, and Ave=2 for T1-WT images, and TR=4,000 ms, TE=96 ms, and Ave=2 for T2-WT images. The ratio of the samples diameter to the birdcage resonators diameter was approximately 55%, 63% and 70%, respectively, for the three elements. This study determined that the best image quality and S/N ratio were obtained when the ratio of the object's diameter was approximately 50∼80%. A general theoretical analysis of the birdcage coil differs in many respects from the experimental results which were influenced by many factors that were not considering when the general theoretical analysis of the birdcage coil was peformed. The induced resistance may be considered as part of the resistive loss if the quantitative value can be determined using a radiation resistance approach.

• Journal of agricultural medicine and community health
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• v.10 no.1
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• pp.36-41
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• 1985

To evaluate the parasitic infection rates among inhabitants in urban area of Seoul, Korea, a total of 5,275 stool and anal swab specimens was obtained from 2,527 male and Z,748 female living in 24 Dongs of 17 Kus. Cases were sampled randomely to represent 1,000 inhabitants refereed to the census in 1980. The methods employed were formalin ether technique to detect helminth ova and protozoan cysts and scotch tape anal swab technique to detect eggs of Enterobius vermicularis. The results obtained are as follows ; 1) Total positive rate of helminthes was 23.5% among 5,275 (male 22.5% and female 24.5%) specimens. Nine kinds of the helminthes were detected and infection rates of each helminth were; Ascaris lumbricoides 4.1%, Hookworm 0.1%, Trichuris trichiura 11.1%, Trichostrongylus orientalis 0.1%. Clonorchis sinensis 1.2%, Metagonimus yokogawai 0.1%, Taenia spp. 0.2%, Hymenolepis nana 0.3 and Enterobius vermicularis 9.6%. 2) Total positive rate of intestinal protozoa was 1.4%. Four kinds of the protozoan cysts were detected and the infection rates of each protozoa were; Entamoeba histolytica 0.15%, E. coli 0.4%, Endolimax nana 0.04% and Giardia lamblia 0.89%. 3) No significant differences in the parasitic infection rate by sex was noticed although male group showed lower infection rate than female group. However the incidence of C. sinensis, M. yokogawai and Taenia spp. was twice as much in female group as in male group. 4) No difference in the infection rate by age was found although E. vermicularis positive rate was highest in "0~9 years group" by 2.1% and C. sinensis infection rate was higher in over "30~39 years group". The parasitic infection rate of the present study was significantly lower than those of previous reports in Seoul area and other provinces.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.258-263
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• 1995

미래 정보와 시대에서 중추적인 역할을 할 광관련 멀티미디어 장비들은 최근 관련 산업계에서 주목을 받기 시작하고 있고 특히 기존 VTR(Video Tape Recorder) 시장을 대체할 차세대 DVDR(Digital Video Disk Recorder)는 기술전쟁이라고 할 정도로 선진 기업의 연구가 치열해지고 있다. DVDR 시스템에서는 필요한 정보들을 레이저빔을 이용한 광학신호로 바꾸어 광디스크에 기록, 재생하는 광픽업이 절대적으로 필요하게 된다. 그런데 광픽업의 위치추종기구인 Actuator는 정확한 위치추종(.+-.1.$\mu$m 오차이내)을 할 수 있는 성능이 요구되며 서보의 특성상 20KHz 이하에서 불필요한 모우드가 가진되지 않는 정밀부품이어야 하므로 Actuator 각 부품의 동적인 특성을 명확히 규명할 필요가 있다. 따라서 본 연구에서는 우선 Actuator 각 부품과 가동부 전체의 중량 및 진동해석을 통해 동특성을 조사하였다. 그리고 Actuator의 중요한 기본성능중 하나인 구동감도 확보여부를 검토할 필요가 있기 때문에 유한요소법 프로그램인 ANSYS를 이용하여 자기회로 부분에 대한 해석을 구하였다. 또한 가동부와 자기회로 등 하위부품을 조립하는 과정에서 발생하는 조립오차로 인해 불필요한 공진과 회전형상이 야기될 수 있으므로 동특성 및 문제점 파악을 위한 민감도 분석이 필요하다. 따라서 본 연구에서는 가동부의 관성 모멘트 값과 강체에 대한 일반식을 이용한 자체 프로그램을 작성하여 조립공차를 구하였다. 이와같은 과정을 통해 구해진 설계값을 바탕으로 실제 제작된 Actuator에 대해서는 비접촉식 측정방법을 통해 동특성값을 측정하였고 이를 해석값과 상호 비교하였다.동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed

• The Journal of Internal Korean Medicine
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• v.28 no.1
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• pp.106-114
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• 2007

Background : Mahuang (Ephedrae Herba, Ephedra sinica $S_{TAPE}$) has been widely used to treat respiratory disease in Asian over the past thousand years. The main ingredient of Mahuang is ephedrine, whose affects on the autonomic nervous system induce some adverse effects like vasoconstriction, hypertension, tachycardia, miosis, insomnia, dizziness, headache, etc. Although there were lots of reports about adverse effects of Mahuang, there were no clinical studies which evaluated the adverse effects of Mahuang on the autonomic nervous system by objective numerical value in the past decade. Objectives : The purpose of this report was to provide an objective assessment of state-trait anxiety that is caused by Mahuang, and to identify anxiety of Mahuang according to different Sasang constitution classifications. Methods : The study design was a double-blind randomized placebo-controlled trial. The subjects of this study were 79 adults aged between 20 to 40 who agreed to participate. Because 8 adults dropped out, a total of 71 subjects entered the study. They were allocated through randomization to a Mahuang group (N=50) and placebo group (N=21). Each group took three opaque capsules (every opaque capsule containing 2g of Mahuang or none) twice a day. To compare the state and trait anxiety before and after taking Mahuang, we checked the anxiety by using STAI-KYZ. Results : The following results were obtained. Short-term administration of Mahuang significantly increased state-anxiety, but in the placebo group, there were no significant changes in state-anxiety. In the Mahuang group except females, there was more significant increase in state-anxiety of Soeumin than Soyangin and Taeumin in the 2nd measurement. Conclusion : It is suggested that the ingestion of Mahuang can increase sympathetic activity and induce anxiety. There was a significant difference among Sasang constitution classification. Especially, the response is stronger in Soeumin than other constitutions. If we use Mahuang according to the Sasang constitution classification in clinic, we could not only minimize the anxiety but maximize the potential curative value.

• Progress in Superconductivity
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• v.7 no.1
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• pp.97-101
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• 2005

Bi-22l2 tubes for fault current limiter (FCL) were fabricated by centrifugal melting process. $SrSO_4$ ($10\;wt.\;\%$) was added to Bi-2212 powder to lower the melting point of Bi-22l2 and to improve the mechanical properties. The BSCCO powder was completely melted at $1300\;^{\circ}C$ using the RF furnace and then poured into rotating steel mold. The steel mold, preheated at $450\;{\circ}C{\sim}550^{\circ}C$ for 2 hour was rotated at $1020{\sim}2520\;RPM$. The solidified BSCCO tube was cooled down to room temperature in the furnace for 48 hours and separated from the mold between Bi-2212 and the mold. $ZrO_2$ solution was used to separate it easily from the mold and Ag tape was attached in the mold inner wall of the mold to analysis electrical property. Bi-22l2 tube was often cracked when the cooling rate was high. BSCCO tubes with $70{\Phi}{\times}100\;mm,\;50{\Phi}{\times}100\;mm$ and $30{\Phi}{\times}150\;mm$ size were fabricated by centrifugal melting process. The $J_{c}s$ of tubes with $50{\Phi}{\times}100\;mm{\times}4.0\;t$ and $50{\Phi}{\times}100\;mm{\times}4.l\;t$ were 178 and $74.2\;A/cm^2$ at 77K, respectively. The processing condition for Bi-2212 tube fabrication was investigated using XRD and SEM analyses.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.14 no.2
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• pp.57-62
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• 1978

When fisherman use the boat seine net to catch anchovy, a large noise (drum can, small drum and small gong) is used to scare the anchovy school along the wing nets, and into the bag net were they are caught. We want to know how much of an effect these s:mnds have on forceing the anchovy school towards the bag net. The underwater sounds of ancho\'y, drum can, small drum and small gong were analyzed in the labroatory. The behavioral responeses to the playback sounds of anchovy feeding and sounds of artificial instruments were also investigated. The feeding and artificial sounds of the samples were recorded by a tape recorder through a hydrophone in an anechoic aquarium. The sound intensity level was measured by means of a sound level meter in an anechoic chamber. The frequency and intensity of various sounds were analyzed with an analyzing system consisting of a ~-octave filter set, a high speed level recorder, an amplifier and an oscilloscope. The most successful recording was edited into a 9 to 10 second sound track and was repeated in a sequence of 9 to 10 second intervals. The sequence was then reproduced into an anechoic aquarium through the underwater speaker. The results of investigation are as follows; 1. The frequency of the feeding sound was 63~80Hz, and the pressure level produced was less than 32db. 2. The frequencies of the artificial sounds were 315~ 1,OOOHz, and the pressure levels were 88~95 db in the air. 3. When a hydrophone was placed 70cm below the surface with artificial sounds (drum can, small drum and small gong) produced 1 meter above the surface, the pressure level decreased about 30db. 4. The feeding sound was ineffective in attracting the anchovy, because of interference from ambient noise. 5. The artificial sounds had such a small effect on the anchovy's that they could not be used in ocean fisheries.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.11a
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• pp.11-11
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• 2000

이동통신기술의 급격한 발달로 고주파회로의 packaging과 interconnect 기술의 고성능화 와 저가격화에 대한 새로운 도전이 요구되고 있다‘ 대부분 기존의 무선통신 부품은 P PCB(Printed Wiring Board)기술을 활용하고 있으나 이러한 기술이 점차로 고주파화되는 경 향을 만족시킬수 없어 새로운 고주파 부품기술이 요구되고 있는 실정이다 .. RF 회로를 구성 하기 위하여 PCB소재의 환경적, 치수안정성 문제를 극복하기 위하여 L TCC(Low T Temperature Cofired Ceramics)기술이 최근 주목을 받고 있다. 차세대 이동통신 기술은 수십 GHz 이상의 고주파특성이 우수하고, 고성능의 초소형의 부품을 저가격으로 제조할수 있으며, 시장의 변화에 기민하게 대처할수 있는 기술이 요구되 고 있으며, 이러한 기술적 필요성에 부합할수 있도록 LTCC 기술이 제안되었다. 이러한 C Ceramic Interconnect 기술은 높은 신뢰성을 바탕으로 fine patterning 기술과 저가의 m metallizing 기술로 가능하게 되었다. 초고주파 통신부품기술은 미국과 유럽 등을 중심으로 G GHz 대역또는 mm wave 대역의 기술에 대하여 치열한 기술개발 경쟁을 벌이고 있으며, 이 러한 고주파 패키징 기술을 바탕으로 미래의 군사, 항공, 우주 및 이동통신 기술에 지대한 영향을 미칠수 있는 기반기술로 자리잡을 전망이다. L LTCC 기술은 기존의 후막혼성기술에 비하여 공정이 단순하고 대량생산이 가능하고 가 격이 비교적 저렴하다. 또한 다층구조로 제작할수 있고, 수동소자를 내장할수 있어 회로의 소형화와 고밀도화가 가능하다. 특히 무선으로 초고속 정보를 처리하기 위하여 이동통신기 기의 고주파화가 빠르게 진행됨에 따라서 고분자재료에 비하여 고주파특성이 우수할뿐아니 라 환경적, 치수안정성이 우수한 세라믹소재플 사용함으로써 고주파 손실율을 저감할 수 있 다 .. LTCC 기술은 후막회로 기술과 tape dielectric 기술이 결합된 기술이다. 표준화된 소재 와 공정기술을 활용하여 저가격으로 고성능소자플 제작할 수 있으며, 전극재료로서 높은 전 도도를 갖고 있는 Ag, Cu, Au 및 Pd! Ag릎 사용함으로써 고주파 손실을 저감시킬 수 있다. L LTCC 기술이 최종적으로 소형화, 고기능 고주파 부품기술로 지속적으로 발전하기 위하여 무수축(Zero shrinkage) 소성기술, 광식각 후막기술 등이 원천기술로서 확립될 수 있어야 하 며, 특히 국내의 이동통신 기술에 대한 막대한 투자에도 불구하고 차세대 이동통신 부품기 술에 대한 개발은 상대적으로 미흡한 실정이므로 국내에 LTCC 관련 소재공정 및 부품소자 기술에 대한 개발투자가 시급히 이루워져야 할 것으로 판단된다. 본 발표에서는 지금까지 국내외 LTCC 기술의 발전과정을 정리하였고, 현재 이 기술의 응용과 소재와 공정을 중심으로한 개발현황에 대하여 조사하였으며, 앞으로 LTCC가 발전 해야할 방향을 제시하고자 한다.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.7 no.2
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• pp.177-191
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• 2000

The purpose of this study to conform the effect of the aseptic dressing method to prevent infusion phlebitis. One quaxi-experimental, nonequvalent control group post-test design was used to evaluate prevention of phlebitis between a control group and an experimental group. The data for the control group were collected from 100 hospitalized patients from July 1 to November 30, 1999. The data for the experimental group were collected from 100 hospitalized patients from December 1, 1999 to March 5, 2000. The control group used paper tape on the IV site and the experimental group used a sterile gauze dressing which was changed every 24 hours. Two sets of instruments were used for this study. First, instrument developed Weinstein(1993) and modified by the researcher was used for judging phlebitis. The second, instrument developed Park(1996) was used for assessment records concerning the phlebitis which developed. Catheter sites were inspected on a daily basis by unit nurses and development of phlebitis was grade and documented. Data were analyzed using $x^2-test$ and stepwise regression The results are summarized as follows : 1. The incidence of phlebitis according to the duration of catheter insertion decreased in the experimental group($x^2=3.56$, p<.05). 2. The incidence of phlebitis according to the duration of catheter insertion decreased in the experimental group($x^2=28.79$, P<.0001). 3. No significant difference was found between the experimental and control groups in the severity of phlebitis. 4. A statistically significant difference between the two groups was found in the incidence of phlebitis according to the location of the insertion site. 5. No statistically significant difference between two groups was found in the incidence of phlebitis by age 6. A statistically significant difference between two groups was found in the incidence of phlebitis by sex($x^2=3.88$, p<.05) 7. Further study revealed that the duration of catheter and sex were predictors of occurrence of the phlebitis, explaining 38.2%, 14.2% of the total variance respectively. In conclusion, the aseptic dressing method is recommended to be prevent infusion phlebitis.

• Journal of Environmental Policy
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• v.10 no.1
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• pp.129-150
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• 2011

This paper proposes an improvement to differentiate assessment procedure for projects in consideration of their environmental impact as a means to improve efficiency in environmental impact assessment ("EIA") procedure. The targets of analysis were limited to lower impact projects. The current EA system in Korea has already attempted to introduce separate proceedings for certain projects.Tangible results from these efforts, however, have been limited. Other countries have adopted a "screening" system to determine whether EIA is applicable to a particular project, and if so, what procedure will be used therein. Therefore, this study suggests the screening as the process wherein need for EIA is determined with respect to projects which have undergone Prior Environmental Review System(PERS) and which appear to have comparatively negligible environmental impact. In this case, EIA can be omitted and the developer can then draft a mitigation plan instead. This study found that exempting certain projects deemed as having low environmental impact can considerably shorten the duration required for both environmental assessment and consultation, thereby improving efficiency. Other expected effects from the adoption of this screening include reduction in delays in project execution due to environmental assessments and reduced red tape through the provision of increased autonomy to developers and the approving authorities.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.34-38
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• 2013

AC Losses for face to face stacks of four identical coated conductors (CCs) were numerically calculated using the H-formulation combined with the E-J power law and the Kim model. The motive sample was the face to face stack of four 2 mm-wide CC tapes with 2 ${\mu}m$ thick superconducting layer of which the critical current density, $J_c$, was $2.16{\times}10^6A/cm^2$ on IBAD-MgO template, which was suggested for the mitigation of ac loss as a round shaped wire by Korea Electrotechnology Research Institute. For the calculation the cross section of the stack was simply modeled as vertically aligned 4 rectangles of superconducting (SC) layers with $E=E_o(J(x,y,t)/J_c(B))^n$ in x-y plane where $E_o$ was $10^{-6}$ V/cm, $J_c$(B) was the field dependence of current density and n was 21. The field dependence of the critical current of the sample measured in four-probe method was employed for $J_c$(B) in the equation. The model was implemented in the finite element method program by commercial software. The ac loss properties for the stacks were compared with those of single 4 cm-wide SC layers with the same critical current density or the same critical current. The constraint for the simulation was imposed in two different ways that the total current of the stack obtained by integrating J(x,y,t) over the cross sections was the same as that of the applied transport current: one is that one fourth of the external current was enforced to flow through each SC. In this case, the ac loss values for the stacks were lower than those of single wide SC layer. This mitigation of the loss is attributed to the reduction of the normal component of the magnetic field near the SC layers due to the strong expulsion of the magnetic field by the enforced transport current. On the contrary, for the other case of no such enforcement, the ac loss values were greater than those of single 4cm-wide SC layer and. In this case, the phase difference of the current flowing through the inner and the outer SC layers of the stack was observed as the transport current was increased, which was a cause of the abrupt increase of ac loss for higher transport current.