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        검색결과 379

        82.
        2018.04 구독 인증기관·개인회원 무료
        Purpose:Conventional pre-saturation pulse for suppressing venous signals cannot be applied to time-of-flight magnetic resonance angiography(TOF-MRA) at 7 Tesla MRI due to specific absorption rate(SAR) limitation. The SAR could be attenuated with using low saturation flip angle, but a few repetitions are needed to reach signals below the steady-state signal of the brain tissues. The purpose of this study was to suppress venous system with clinically acceptable acquisition time by using 90 degree flip angle. Methods:The standard slab-selective radio-frequency and gradient waveform were modified to new-shaped models by minimum-time variable-rate selective excitation(Min-VERSE) algorithm. Excitation slice profile was measured and evaluated by a phantom scan. In volunteer measurement, the vessel-tissue contrast ratio of the sinuses(VTCR_S) and middle cerebral artery(VTCR_MCA) were assessed in correlation to surrounding tissue and compared to the values measured by the conventional TOF(cTOF) pulse sequence. Results:The experimentally-measured profiles showed that there was good agreement between conventional and modified pulse. The total scan time was 5 min 55 sec(Min-VERSE 90 FA, TR 28 ms) and 8 min 50 sec(90 FA, TR 42 ms). The quantitative results of ROI analysis were nearly similar, except the venous signal and VTCR_S at Min-VERSE 90 FA. Conclusions:We have presented that the use of Min-VERSE with high flip angle was useful. The total acquisition time was faster about 3 minutes and the signal analysis was hardly different to the values acquired by the values of 90 FA at cTOF. Since 7T MRI has been suitable for ultra-high resolution imaging, our protocol would be used by default for diagnosing various intracranial vascular pathologies.
        83.
        2018.04 구독 인증기관 무료, 개인회원 유료
        In this paper, the result of application of this simple method of vibration analysis developed by the author, to the special orthotropic plates with variable cross-section, and with a pair of opposite edges simple supported and the other pair of opposite edges free is presented. This problem represents the simple-supported single span bridge system without effective longitudinal edge beams. The effect of concentrated point mass/masses is also studied.
        3,000원
        84.
        2018.04 구독 인증기관·개인회원 무료
        We carried out a dynamic instability assessment of carbon nanotube reinforced composite (CNTRC) and carbon nanotubes/fiber/polymer composite (CNTFPC) skew plates based on the high-order shear deformation plate theory (HSDT). The multiscale interactions between carbon nanotube (CNT) ratios and skew angles on the dynamic instability for various length-thickness ratios are studied using a two-dimensional finite element model developed for this study. The results were verified by those reported in the literature show the interactions between the CNT reinforcement and skew angles in the skew laminate. Numerical examples show the importance of CNT reinforcement when assessing the dynamic instability of CNTRC and CNTFPC skew plates.
        85.
        2018.04 구독 인증기관·개인회원 무료
        The spined soldier bug, Podisus maculiventris (Hemiptera: Pentatomidae), can feed on more than 70 species of insects including immature stages of Lepidoptera and Coleoptera. P. maculiventris is native to North America and there was an attempt and failure to import P. maculiventris to South Korea in 1970s. Recently, P. maculiventris was successfully re-introduced to South Korea and is being contained and reared in a quarantined facility at the National Institute of Agricultural Sciences, Rural Development Administration, South Korea. In this presentation, we will introduce this new biological control agent targeting major lepidopteran and coleopteran pests in agriculture and forest. In addition, current research on mass rearing and aerial release of P. maculiventris using drones will be presented.
        86.
        2018.04 구독 인증기관 무료, 개인회원 유료
        This study aims to provide a real-time information to the driver by effectively operating the advanced safety device attached to the freight vehicle, thereby minimizing insecure behavior of the driver such as speeding, rapid acceleration, sudden braking, And improve driving habits to prevent accidents and save energy. Advanced safety equipment is a device that warns the driver that the vehicle leaves the driving lane regardless of the intention of the driver and reduces the risk of traffic accidents by mitigating or avoiding collision by detecting a frontal collision during driving.The main contents of this report are as follows: In case of installing a warning device on a lane departing vehicle (excluding a light vehicle) and a lorry or special vehicle with a total weight exceeding 3.5 tonnes, the driver must continue to operate unless the driver releases the function.In addition, when the automatic emergency braking system is installed, the structure should be such that the braking device is operated automatically after warning the driver when the risk of collision with the running or stopped vehicle in the same direction is detected in front of the driving lane.
        4,000원
        87.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 막결합생물반응조(MBR)공법을 비롯한 하수고도처리공법에서 유입하수량의 변화에 따른 슬러지 특성 변화를 파악하고자 하였다. 일 1.5톤을 처리하는 모형실험시설에서 설계유량 대비 유입하수량을 100, 70, 40, 10%로 변 화시켜가며 이에 따른 비탈질속도(specific denitrification rate)와 비질산화속도(specific ammonia oxidation rate)의 변화를 측 정하였다. 각 공법의 폭기조에서 채취한 슬러지의 비질산화속도는 유입하수량 100% 조건에서 세 가지 공법 모두 유사한 값 (0.10 gNH4/gMLVSS/day)으로 측정되었다. 유입하수량이 70%에서 40%로 감소함에 따라 비질산화속도가 크게 감소하는 경향을 나타냈다. 비탈질속도 역시 유입하수량이 감소함에 따라 최대 50%가량 감소하였다. 유입하수량이 감소할수록 비탈질속 도와 비질산화속도가 감소하는 경향을 나타냈으나 원수의 총질소 농도와 반응조 내 미생물 농도를 고려하면 질소제거율에 영향을 미칠 정도는 아니었다. 따라서 유입하수량이 감소하는 경우에도 반응조 내 미생물 농도를 높게 유지할 수 있다면 안정적인 질소 제거가 가능할 것으로 판단된다.
        4,000원
        88.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: The Berg Balance Scale (BBS) and the Fullerton Advanced Balance (FAB) scale have been used to assess balance function in patients with chronic stroke. These clinical balance scales provide information about potential risk factors for falls. Objects: The purpose of this study was to investigate the incidence of and risk factors of falls and compare the predictive values of the BBS and FAB scale relative to fall risk in patients with stroke through receiver operating characteristic analysis. Methods: Sixty-three patients with stroke (faller=34, non-faller=29) who could walk independently for 10 meters participated in this study. The BBS and FAB scale were administered. Then, we verified the cut-off score, sensitivity, specificity, and the area of under the curve. Results: In this study, the BBS and FAB scale did not predict fall risk in patients with stroke in the receiver operator characteristic curve analysis. A cut-off score of 37.5 points provided sensitivity of .47 and specificity of .35 on the BBS, and a cut-off score of 20.5 points provided sensitivity of .44 and specificity of .45 on the FAB scale. Conclusion: The BBS and FAB scale were not useful screening tools for predicting fall risk in patients with stroke in this study, but tho
        4,000원
        89.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study aims to analyze how the installation of advanced warning devices affects individual drivers’driving behaviors with operating record data collected from 100 vehicles. METHODS: With collected data, the changes in individual drivers’driving behaviors, such as Forward Collision Warning (FCW) and Lane Departure Warning (LDW), were investigated with respect to the cumulative distance traveled and driving time. For the analysis, operating record data collected from 100 vehicles for seven months were used. RESULTS: The results showed that individual drivers’driving behaviors could be categorized into six different types. In addition, most of the drivers showed unstable warning patterns in the initial stage after installation of an advanced warning device. Approximately 40% of vehicles equipped with advanced warning systems were found to have positive effects, indicating that the frequencies of both FCW and LDW had been continuously decreasing after installation of the system. CONCLUSIONS : The warning device might be helpful for making drivers’driving behaviors safer. Driving behaviors during the initial stage of the system installation, which might be regarded as an adaptation phase, were found to be very unstable compared with normal situations, indicating that adequate education and training should be provided to all the drivers to prevent operator disruption at the initial installation of the system.
        4,000원
        90.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The safety management of feeds has become a very important factor for food safety and legislation and system improvement are being implemented to prevent the hazardous factors from livestock products. The range of heavy metals in feed hazardous factors was similar among countries, but the As maximum limit was strengthened in Korea compared to China. Regulation of residual pesticide and radioactivity was only controlled in Korea. The range and maximum limit of mycotoxin were strictly controlled in China compared to Korea. In order to enhance the feed safety in Korea, it is necessary to improve the policy, strengthen the range of the feed hazard and the maximum limit and carry out the research related to the feed safety.
        4,000원
        91.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A centrifugal cyclone dust collecting apparatus includes a hydro cyclone dust collecting apparatus for separating solid or liquid using liquid or suspension as a medium. In this study, the formation mechanism and improvement of air core and inner air layer were confirmed through Particle Image Velocimetry. These results showed that the modified experimental model was designed in the conventional method suitable for the separation of juvenile fish and eggs. The inlet speed of the multi-stage hydrocyclone dust collector, which can increase the inlet velocity and minimize floatage in the turbulence chamber, was increased from 0.15 to 0.30 m/s. As a result, the air core was stably formed, the inner air layer was increased with increasing speed. In addition, the dust collecting efficiency of egg and juvenile fish was 97.8% on average, It can infer that this system confirmed the ability to efficiently collect particles of 40 μm or more.
        4,000원
        93.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Rasch analysis has the advantage of placing both the items and the person along a single ratio scale and calibrates person ability and item difficulty onto an interval scale by logits. Therefore, Rasch analysis has been recommended as a better method for evaluating functional outcome questionnaires than traditional analyses. Objects: The aim of current study was to investigate item fit, item difficulty, rating scale, and separation index of the Korean version of the Fullerton Advanced Balance (KFAB) scale using Rasch analysis. Methods: In total, 93 patients with stroke (male=58, female=35) participated in this study. To investigate the item fit, difficulty, rating scale, and separation index of the KFAB scale, Rasch analysis was completed by the Winsteps software program. Results: In this study, all items of the KFAB scale were included in the Rasch model. The most difficult item was ‘standing with feet together and eyes closed’, and the easiest item was ‘two-footed jump’. The rating scale was a 4-point scale instead of the original 5-point scale. Person and item separation indices showed high values that can identify a person with a wide range of balance ability. Conclusion: The KFAB scale appears to be a reliable and valid tool to assess balance function in patients with stroke. Furthermore, the scale was found to discriminate among stroke patients of varying balance abilities.
        4,000원
        96.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO micro/nanocrystals with different morphologies were synthesized by thermal evaporation of various zinc source materials in an air atmosphere. Zinc acetate, zinc carbonate and zinc iodide were used as the source materials. No catalysts or substrates were used in the synthesis of the ZnO crystals. The scanning electron microscope(SEM) image showed that the morphology of ZnO crystals was strongly dependent on the source materials, which suggests that source material is one of the key factors in controlling the morphology of the obtained ZnO crystals. Tetrapods, nanogranular shaped crystals, spherical particles and crayon-shaped crystals were obtained using different source materials. The X-ray diffraction(XRD) pattern revealed that the all the ZnO crystals had hexagonal wurtzite crystalline structures. An ultraviolet emission was observed in the cathodoluminescence spectrum of the ZnO crystals prepared via thermal evaporation of Zn powder. However, a strong green emission centered at around 500 nm was observed in the cathodoluminescence spectra of the ZnO crystals prepared using zinc salts as the source materials.
        3,000원
        97.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        하⋅폐수 처리 기술은 종래 단순 오염물질 처리에서 에너지 및 자원 절약형의 고도처리 기술로 발전되고 있으며, 공공 수역으로의 오염 물질과 유독 물질 배출을 최소화하고 설치⋅운영의 효율성을 높이기 위해 IT 및 BT와 같은 다양한 기 술을 접목한 융합형 기술로 진화하고 있다. 국내 하⋅폐수 처리기술의 발전 추이를 살펴보기 위해 등록된 특허기술을 수집⋅ 조사하여 연도별⋅부문별로 분류하여 분석하였다. 본고에서 2010년~2017년 5월 간의 관련된 특허 등록 내용을 생물학적⋅ 물리화학적 처리공정, 장치 및 기기, 소재⋅제재, 슬러지처리, 분리막, 공정제어기술 등 10개 분야의 42개 세부 영역으로 나누 어 추세를 분석했다. 총 3,356건의 특허가 등록되었으며 2013년에 638건으로 최고치를 기록한 이후 다소 감소하여 연간 3~400여 건을 유지하고 있다. 등록된 특허 총 건수는 아직 다른 국가에 비해 적지는 않으나 공정 제어 및 기기 분야, 신개념 처리 기술과 같이 세계 시장을 선도할 수 있는 첨단 기술의 특허는 타 분야에 비해 미흡한 것으로 나타났다.
        4,600원
        98.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        식후 소화불량 및 복통을 주소로 내원한 54세 여자 환자가 영상 검사 및 간조직검사를 통해 절제 불가능한 국소 진행성 간내담관암으로 진단을 받았다. 환자는 진단 이후 총 40주기 의 gemcitabine 및 cisplatin 병합 항암화학요법 이후 수술적 절 제가 가능하다고 판단되어 확대 간우엽절제술 및 간문맥 구역 절제술을 시행 받은 뒤 병리학적 완전 관해로 판정되어 추가적 치료 없이 경과를 관찰하며 6년 이상 장기생존 중이다. 본 증례를 통해 절제가 불가능한 국소 진행성 간내담관암 또한 적극적인 항암화학요법을 통해 병리학적 완전 관해에 이르러 장기생존을 도모할 수 있음을 알게 되었으며, 향후 이와 비슷한 환자의 치료에 있어 최근 연구되고 있는 다양한 방법 들을 이용한 적극적인 치료가 필요하다고 생각된다.
        4,000원
        99.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a model was developed to predict for Disinfection By-Products (DBPs) generated in water supply networks and consumer premises, before and after the introduction of advanced water purification facilities. Based on two-way ANOVA, which was carried out to statistically verify the water quality difference in the water supply network according to introduce the advanced water treatment process. The water quality before and after advanced water purification was shown to have a statistically significant difference. A multiple regression model was developed to predict the concentration of DBPs in consumer premises before and after the introduction of advanced water purification facilities. The prediction model developed for the concentration of DBPs accurately simulated the actual measurements, as its coefficients of correlation with the actual measurements were all 0.88 or higher. In addition, the prediction for the period not used in the model development to verify the developed model also showed coefficients of correlation with the actual measurements of 0.96 or higher. As the prediction model developed in this study has an advantage in that the variables that compose the model are relatively simple when compared with those of models developed in previous studies, it is considered highly usable for further study and field application. The methodology proposed in this study and the study findings can be used to meet the level of consumer requirement related to DBPs and to analyze and set the service level when establishing a master plan for development of water supply, and a water supply facility asset management plan.
        4,000원
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