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        검색결과 363

        121.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적 : 3.0T 자기 공명 영상에서 강자성 임플란트로 인해 발생한 자화감수성 인공음영에 대한 시퀀스별 WARP기법의 적정한 VAT(view angle tilting)값을 알아보았다. 대상 및 방법 : 자화감수성 인공음영(susceptibility artifact image)이 head용 워터 팬텀영상의 왜곡정도를 평가하기 위하여 head용 워터 팬텀에 강자성 임플란트(ferromagnetic implant)인 금속 와이어를 부착하여 영상을 획득하였다. 진행하였고(VAT(view angle tilting)) Warp를 사용하였다. 사용된 장비는 3.0T MRI system(MAGNETOM Skyra, Siemens, Munich, Germany)이었으며 20ch head/neck coil을 사용하여 TSE T2, TSE T1, FLAIR, Turbo IR T1 시퀀스에 WARP를 적용하여 VAT를 0~100% 범위내에서 10%씩 변화하여 각각 24개의 axial 영상을 얻었다. TSE T2 영상변수는 TR/TE 4410ms/79ms, Matrix 512×291이었으며, TSE T1 영상변수는 TR/TE 693ms/10ms, Matrix 512×291이었으며, Turbo IR T1 영상변수는 TR/TE 2000ms/9.5ms, Matrix 384×307이었으며, FLAIR 영상변수는 TR/TE 9000ms/96ms, Matrix 384×180이었다. 시퀀스별로 slice thickness 4mm, slice gap 0.4mm, NEX 1, bandwidth는 500Hz 였다. 정량평가는 팬텀영상의 대부분을 ROI로 설정 하여 표준편차를 구하였다. 정성 평가는 팬텀 영상 내에 dark area크기, image blurring 정도를 5점 척도로 하여 영상의 변화가 없는 경우 1점, 영상의 질이 약간 우수한 경우 2점, 보통 3점, 우수한 경우 4점, 매우 우수한 경우 5점으로 숙련된 방사선사 3명이 관찰 후 평가하였다. 결 과 : 정량분석으로 TSE T2와 TSE T1의 표준편차(SD)는 VAT 10%에서 VAT 적용전보다 많은 감소를 보였으며, VAT가 증가 할수록 감소하는 경향을 나타냈다. 그러나 IR 계열의 FLAIR와 Turbo IR T1은 WARP의 적용에 따른 영상차이가 없었다. 변동계수는 모든 시퀀스에서 30%이하였다. 또한 VAT 변화에 따라 영상의 위치변화도 나타났다. 정성분석으로 TSE T2는 VAT가 30~60%일 때 우수한 것으로 나타났고, TSE T1은 VAT가 10~70%일 때 우수한 것으로 나타났다. FLAIR와 Turbo IR T1은 WARP사용에 따른 영상의 변화가 없었다 결 론 : WARP는 TSE T2와 TSE T1의 자화감수성 인공음영을 줄이는데는 매우 효과적인 영상기법이었다. 그러나 WARP는 VAT를 증가시키면 image blurring도 증가함으로 VAT값을 최소화해서 사용 되어져야 할 것으로 사료된다.
        4,000원
        122.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적 : 족관절 염좌 환자의 자기공명영상 검사 시 전하경비인대(AITFL)와 전거비인대(ATFL)를 관찰하기 위한 사방향 관상면(oblique coronal plane) 2D FSE 영상과 Isotropic 3D FSE Cube 영상의 비교를 통하여 그 유용성에 대하여 알아보고자 하였다. 대상 및 방법 : 2013년 10월부터 2013년 12월까지 족관절 염좌를 주 호소로 본 기관을 내원한 환자 15명(남자: 6명, 여자: 9명)을 대상으로, 사방향 관상면 2D FSE 기법과 시상면 3D FSE Cube 영상기법을 이용하여 AITFL과 ATFL의 영상을 획득하였다. 획득한 영상에서 AITFL과 ATFL, 골조직, 배경신호의 SI 및 CNR을 측정하고, Mann-Whitney U-검정으로 두 기법간의 통계적 유의성을 검증하여 정량적 평가를 하였다. 또한 영상의학의 2명이 각각의 영상에서 보여지는 AITFL과 ATFL의 형태 및 연속성, 부분용적에 의한 인공음영, 병변의 묘사정도의 3가지 항목을 4점 척도(0: 진단불가-Non diagnostic, 1: 부족함-Poor, 2: 적합함-Adequate, 3: 좋음-Good)로 평가하고, 평가결과 간의 일치도 검증을 위하여 Kappa-value(SPSS 19) 검정을 통해 통계적 유의성( p<0.05)을 검증하여 정성적 평가를 하였다. 영상획득에 사용된 장비는 3.0T MR 장비와 Extremity RF Coil을 사용하였다. 결 과 : 정량적 평가에서 CNR의 평균값은 AITFL의 경우 사방향 관상면 2D FSE영상에서는 10.72±0.01, 3D FSE Cube 영상에서는 18.66±0.52이었다. ATFL의 경우에는 사방향 관상면 2D FSE 영상에서는 5.62±0.98, 3D FSE Cube 영상에서는 8.15±0.65이었다. AITFL과 ATFL 모두 3D FSE Cube 영상에서 CNR 값이 높았으며, 두 영상기법 간의 CNR 값의 비교는 통계적으로 유의하였다( p<0.05). 정성적 평가에서 관찰자 1에 의한 AITFL의 형태 및 연속성, 부분용적에 의한 인공음영, 병변의 묘사정도의 평가결과는 사방향 관상면 2D FSE 영상의 경우 2.4±0.5, 2.5±0.5, 2.6±0.5의 순으로 값을 나타냈고, 3D FSE Cube 영상에서는 2.8±0.3, 2.9±0.2, 2.9±0.2의 순으로 값을 나타냈다. ATFL의 경우는 사방향 관상면 2D FSE 영상에서 2.5±0.5, 2.3±0.4, 2.5±0.5의 순으로 값을 나타냈고, 3D FSE Cube 영상에서는 2.8±0.4, 2.9±0.2, 2.9±0.2의 값을 나타냈다. 관찰자 2에 의한 AITFL의 형태 및 연속성, 부분용적에 의한 인공음영, 병변의 묘사정도의 평가결과는 사방향 관상면 2D FSE 영상의 경우 2.4±0.5, 2.3±0.8, 2.6±0.4의 순으로 값을 나타냈고, 3D FSE Cube 영상에서는 2.8±0.3, 2.8±0.3, 2.8±0.3의 값을 나타냈다. ATFL의 경우는 사방향 관상면 2D FSE 영상에서 2.8±0.4, 2.4±0.5, 2.8±0.5의 순으로 값을 나타냈고, 3D FSE Cube 영상에서는 2.9±0.2, 2.9±0.2, 2.9±0.2의 순으로 값을 나타냈다. AITFL과 ATFL 모두 3D FSE Cube 영상에서 평가 결과가 높게 나타났으며, 두 관찰자 간 평가결과의 일치도 검정은 통계적으로 유의하였다( p<0.05). 결 론 : 족관절 염좌 환자에서 3D FSE Cube 영상이 사방향 관상면 2D FSE 영상에 비해 AITFL과 ATFL의 손상 감별 및 기타 인대손상의 평가에 매우 유용하다는 것을 알 수 있었다
        4,800원
        123.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 예이츠의 "어부"가 시적 발달의 어디에 위치하는지를 잠간 보고, 어떻게 이 시가 특이하고 흥미롭게 자아의 재창출을 시도하는지 보여주려고 한다. 본인은 시적 자아 자체의 과정을 면밀히 검토하기 위해서, 최초의 시의 초안으로 돌아가서 이 시가 어떻게 순수한 창조의 이미지를 만들고 보존하는지를 보여 주려하는데, 이 과정에서 이미지는 중첩되고 복잡해진다. 1910년대에 보다 개인적이고 구체화된 자아에의 과감한 경향을 보이는 시인은, 반면에, 미리 후기 모더니스트적 면을 보인다. 동시에, 이상화된 고독한 시골의 인물에 대한 애정과 당대의 청중에 대한 회의시은 그가 아직도 낭만주의적 작가인 것을 보여준다. "어부"는 그가 거의 최상의 놀랄만한 재창조적 시인임을 보여준다.
        4,300원
        124.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is aimed to analyze the hydrodynamic characteristics of the cage net in the circulating water channel. It visualized wake flows using a PIV (paricle imaging velocimetry) and analyzed the flow velocity distribution. In addition, the vorticity and turbulence intensity were analyzed from the wake flow distribution and compared changes by flow velocity. Results showed that the average turbulence intensity in the circulating water channel was very stable showing less than 1% in the range between 0.2 and 0.8 m/s. The drag coefficient affecting to the netting was estimated to be 1.35. The flow decreasing rate of the wake in the middle of the netting was 2.1% at the range of 0.2 m/s and it was constant at 6.6―6.9% over the range of 0.4 m/s irrespective of velocity increases. Finally, the change of turbulence intensity by netting and knot mesh could be confirmed. These results can be utilized as a basic information for the future research of flow characteristics by fishing nets and meshes.
        4,000원
        125.
        2014.11 구독 인증기관 무료, 개인회원 유료
        We performed the quantitative analysis using MATLAB for slice thickness, spatial resolution, and low contrast resolution with the 50 received images which have suitable judgement by scanning AAPM phantom using GE, PHILIPS, SIEMENS, and TOSHIBA. Slice thickness and spatial resolution were measured by using full width at half maximum(below FWHM). Spatial resolution was confirmed that FWHM interval more than 1.0 mm size. Low contrast resolution was measured that how close by using Roundness Index(below RI) until 6.4 mm size. The spatial resolution 9 images and low contrast resolution 10 images which have disapproved judgement were also had the quantitative analysis. The statistic analysis was judged to have statistically significant differences when p-value is less than 0.05 through SPSS statistics 19.0 and T-test (paired t-test). For slice thickness 5 mm, the average qualitative evaluation group shows 4.98 mm and quantitative evaluation group shows 5.02. For slice thickness 10 mm, the average qualitative evaluation group shows 9.98 mm and quantitative evaluation group shows 9.86. No significant differences (p=0.07, p=0.06) with 5 mm and 10 mm. It confirmed the interval for all FWHM until 1.75, 1.50, 1.25, 1.00 mm as approved images on spatial resolution ,and the average distance was 0.102 mm and the minimum distance 0.054 mm. For disapproved images, all interval was not showed under 1.00 mm. For low contrast resolution, spproved image’s RI value shows average 0.81 and minimum 0.77. The disapproved image’s RI average shows 0.70. Statiscally significant differences were presented (all p<0.05) following hole size.
        4,500원
        126.
        2014.10 구독 인증기관·개인회원 무료
        127.
        2014.09 구독 인증기관 무료, 개인회원 유료
        Ischemic stroke is the most common type of stroke in humans. The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI) in a canine model of stroke. Ischemic stroke was induced by using prepared autologous thrombus. The dogs were placed in lateral recumbency on the operation table and the cervical area of each dog was sterilized by using alcohol. After making a cervical incision, the common carotid artery and internal carotid artery (a branch of the common carotid artery that supplies an anterior part of the brain) were exposed. A 200 μL injection of the autologous thrombus prepared 24 hr prior to surgery was delivered with a 20 gauge venous catheter through an internal carotid artery. After successful delivery of the autologous thrombus, the venous catheter was removed, and the cervical incision was sutured. Neurologic signs including generalized seizures, tetraparesis, and altered mental status, were observed in all 3 dogs after induction of ischemic stroke and the signs manifested immediately after awakening from anesthesia. T1- and T2-weighted images and fluid-attenuated inversion recovery (FLAIR) images of the brain were acquired 1 day before and 1 day after surgery. On the day following ischemic stroke induction, MRI revealed multifocal lesions in the cerebral cortex and subcortex such as T1 hypointensity, T2 hyperintensity, FLAIR hyperintensity, and diffusion-weighted hyperintensity in all 3 dogs. Upon postmortem examination, ischemic lesions were found to be consistent with the MRI findings and they were unstained with 2% triphenyltetrazolium chloride. Histologic features of the earliest neuronal changes such as cytoplasmic eosinophilia with pyknotic nuclei were identified. Neuropil spongiosis and perivascular cuffing were also prominently observed at the infarcted area. The present study demonstrated the features of MRI and histopathologic findings in canine ischemic stroke models.
        4,000원
        128.
        2014.07 구독 인증기관 무료, 개인회원 유료
        Understanding the buyer decision processes has been one of the core subjects for marketing researchers. Decision-making has been referred as a psychological construct, which could be inferred from the behavior as a commitment to an action. The main scope of this project has been centered at a blended approach between economic and psychological models of decision-making with giving more credit to the possible psychological and physiological counterparts of the buying process. The technological developments and interdisciplinary studies especially in the last decade have paved a valuable path for various research tools that could contribute to the classical models of marketing. The contribution of neuroscientific knowledge and methods has provided a considerable insight for the question what is happening inside the brain. Since neuroscience has targeted at investigating the human brain with respect to internal and external factors, an applied form of neuroscience, neuromarketing, has been useful for the marketing research in general and for modeling the buying processes in specific. Thepresent empirical study could be accepted as one of these initial steps and possible contributions in testing the role of neuroscientific methods in buyers’ decision processes and providing a useful insight in interpreting the prefrontal brain dynamics during their possible buying decisions. Buying decisions have been claimed to be “malleable” (Schwartz, 2004) associated with the available information beneath instead of having well-defined preferences (Bettman, Luce, & Payne 1998). It has been demonstrated that excessive prices have an impact on increasing the insular activity and decreasing the activity in the medial prefrontal cortex, which have been shown to be active during monetary decision-making processes (Knutson et al., 2007). It has also been argued that affect factors and unfair prices have a direct interrelationship (Xia, Monroe, & Cox, 2004). These findings have been in line with the somatic markers hypothesis by Bechara and Damasio (2005) who argue that our brains predict the possible outcomes in a setting depending on our interoceptive emotional signals prior to decision-making. These emotional signals have been considered to have direct guidance during decision-making processes like purchasing. Reward processingmagnitude and valence have been associated with economic transactions by using event-related potentials (Yeung&Sanfey, 2004). Prefrontal cortex has been found to be a critical region that is observed to be active during various cognitive processes including decision-making, executive functions and reasoning. The decision-making processes could generally be divided into two main segments: (1) cognitive and (2) emotional counterparts and prefrontal regions could simply be correlated with the cognitive aspects rather than the emotional side which is mostly considered to be driven by the subcortical regions. The neuroscientific studies in the literature shed light into this dissociation with various empirical findings such that nucleus accumbens activation correlates with reward anticipation, and medial prefrontal cortex (MPFC) activation correlates with gain outcomes (Knutson et al., 2001). Option valuation, probability estimation, reward and cost anticipation and strategy formation have been some of the decision processes that are considered to be executed by the prefrontal cortex. Medial prefrontal cortex has been shown to have a direct role in the calculation of values (or valuation) of options like the statement of the preferences with the presented product and it has been demonstrated that the activation in medial PFC has been in correlation with the subjective product preferences (Paulus & Frank, 2003). The preference judgments between healthy and unhealthy food items have also been shown to activate the medial prefrontal cortex during the valuation of the options (Hare et al., 2011). This valuation of options have been shown to be not restricted to product valuation but rather it is possible to speak of a general valuation system that is also effective in valuation of the monetary rewards (Bastenet al., 2010). Functional near-infrared spectroscopy (fNIRS) method has been utilized to investigate various cognitive faculties. Izzetoglu et al. (2007) used fNIR in a series of experiments to study brain activations during several types of tasks that measure cognitive output. They used a videogame-like task called the Warship Commander Task in which the participants tried to manage varying numbers of airplanes and the amount of cognitive load of the participants was quantified by fNIR. In other experiments, n-back task was used to investigate working memory load on the prefrontal cortex and anagram problems of varying difficulty were used to measure brain activations correlated to problem solving efforts. fNIR was also used in a visual oddball paradigm to assess attention levels of the participants. Across this series of studies, fNIR was shown to be a reliable method for quantification of prefrontal cortex activations. The change in the blood flow has already been shown to illustrate the activation level. Kumagai (2012) investigated personal product preference in fNIR study. Subjects were asked which one of the two products presented they would prefer and then were shown the same products consecutively before making a final decision. Researchers were able to classify product preferences by analyzing blood flow changesvia fNIR.A similar study was conducted by Luu and Chau (2009) to detect product preference via fNIR in a single-trial task. Subjects evaluated two possible products to state their preference and a single-trial task was adequate to analyze fNIR signal for preference detection. We have aimed to observe the neural correlates of buying versus non-buying decisions by using optic neuroimaging method, functional near infrared spectroscopy (fNIR). To the best of our knowledge, no study has directly investigated the fNIR correlates of buying versus non-buying. We have mostly adapted the experimental design of Knutson et al. (2007) that could be accepted as a realistic model for an idealized case of a possible buying decision by which the participants see a product image, then its price (under the product image) and finally the decision screen by which the participant has to respond positively or negatively to the buying decision. There have been four main hypotheses for this empirical study. Firstly, the preferences and buying decisions of the participantsduring the experiment are highly correlated with the consumption rates in their lives.The participants in both experiments are likely to choose the products, which they declare in the subjective reports. Secondly, the reaction times of the purchasing versus not purchasing decisions differ depending on the final decisions of the participants.Thirdly, the preference versus non-preference decisions of the participants causes different brain activation patterns via fNIR. Fourthly, the buying versus non-buying decisions of the participants causes different brain activation patterns via fNIR. The buying decisions would elicit more activation in the prefrontal regions due to the possible involvement of monetary-centered decisions as well as the contribution of working memory in these higher-order processes. This empirical project consists of two experiments. First one has been done without a real purchasing outcome –the participants were choosing to buy the products or not but they were not given the products at the end of the experiment. Whereas in the second experiment, the participants had the chance to buy the products they selected to buy. 78 products were used in the task and the total duration of the experiment was 26 minutes.The products consisted of 3 main groups: food, cleaning and personal care products. There were 39 products in the food group (e.g. milk, cheese, coke), 17 products in the cleaning group (e.g. detergents) and 22 products in the personal care group (e.g. deodorant, shampoo, toothpaste). The prices of the products were taken from the supermarkets around Ankara and Istanbul.28 participants have participated in the first round of the experiment, which has done without actual buying endowment but instead participants have pretended to buy the products that they actually preferred. The participants for this experiment were undergraduate students from the Middle East Technical University and they were paid 10 Turkish Liras for their participation in the experiment. The second experiment was performed with the same experimental design but this time each of the participants were given 10 TL for their participation and 40 TL to purchase the products they prefer during the experiment. 11 participants (6 males and 5 females) have attended to this second experiment. The participants were also told that if they do not purchase any products or they do not spend all of the money, they would be able to get half of the unspent money. Since the products have been presented with their actual market prices, it has been much more likely and advantageous for the participants to spend all of their money.The data of one of the participants was excluded due to handedness, and 2 of them were excluded due to excessive artifacts. After the completion of the task, each participant filled out a survey about their frequency of use (Range;1: Never – 5: Frequently) for each of the 78 products. The data obtained from 16 channels via fNIR at a temporal resolution of 2 Hz consists of 4 main parameters: Oxygenation (oxy), Total Hemoglobin (hbt), Hemoglobin (hb) and Hemoglobin 2 (hb2). Each reading is taken for 4 stages (fixation, picture, price, decision). The main underlying assumption has been to observe an increase in the relative concentrations of oxy and hbt values depending on the higher PFC activation during the product demonstration when compared to the fixation screen (that is presented before each block). Almost all of the channels illustrate a difference on average between buying and non-buying conditions. We have also expected to observe a significant difference in activation levels between purchasing and non-purchasing decisions. The processed data has been statistically analyzed with SPSS 20.0. Repeated Measures (RM) ANOVA has been performed in order to observe if the buying versus non-buying decisions had a statistically significant effect on the fNIR signals that are averaged for each block of product, price and decision screens. The independent variable has been the binary buying decisions of the participants. The results of the RM ANOVA test have demonstrated that the first experiment done with preference of the products do not implicate any significant difference between buying and non-buying decisions. Thus our third hypothesis was based on observing a significant change in prefrontal activations due to participants’ product preferences (versus non-preferences). Thus it is more likely that the non-monetary simulated “buying” decisions, which do not actually end with purchasing products, do not elicit sufficient activation in the prefrontal regions to provide a detectable difference between preferred and non-preferred cases. Whereas the same statistical test performed for the results of the second experiment implicate significant difference for the buying versus non-buying decisions for 2 of 16 voxels: V1, V8. For N=11, significant levels of activation was observed on Voxel 1, F(1.00, 9.00) = 8.35 , p < 0.2 (Greenhouse-Geisser corrected) and Voxel 8, F(1.00, 9.00) = 5.50 , p < .05 (Greenhouse-Geisser corrected). The waveforms averaged over 11 subjects show a significant separation among purchase and no purchase decisions especially in Voxels 1 and 8. This finding has been a support for our fourth hypothesis, which has been a modification of the third one. Our third and fourth hypothesis has hold that the buying decisions versus non-buying decisions elicit higher activation among the prefrontal cortices of the participants when the decisions end with the actual purchasing decision. To sum up, this empirical study could be accepted as a step for the specific research field of buying decision processes and neuromarketing research in general. The obtained results clearly implicate that specific prefrontal regions –both lateral and medial- might be activated differently depending on the final buying decisions via the optic neuroimaging device, fNIR. Beside the technical limitations such as the appropriate presentation time, this study performed with fNIR method could be used as a baseline work for understanding the psychological and physiological dynamics of buying decisions and in the short-term several factors can also be investigated with this method. Therefore, it might also be possible for researchers to adapt this methodology for the sector-specific marketing research especially for pricing in the long-run.
        4,000원
        129.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고추의 수분스트레스 반응을 최적으로 계측할 수 있는 알고리즘을 개발하기 위해 초분광 단파 적외선 영상기술을 적용하였다. 수분스트레스에 노출된 고춧잎의 단파적외선 분광영상을 획득하고 ANOVA 분석을 이용하여 수분스트레스 반응을 가장 잘 반영하는 파장영역을 선정하였다. 고춧잎의 단파적외선 초분광 영상을 이용하여 ANOVA 분석을 수행한 결과 수분스트레스 판별을 위한 최적 파장은 1449nm으로 물분자의 광 흡수 영역대와 거의 일치하였다. 최적 파장에서의 고춧잎 상대반사값을 가우시안 회귀분석을 통해 정상군과 토양흡착수압이 −20kPa과 −50kPa일 때의 스트레스군을 구분할 수 있는 임계값을 계산하고 이 값을 기준으로 단파적외선 영상을 이진화하여 수분스트레스 반응을 판 단할 수 있는 최종영상을 구축하였다. 결과 영상에서 정상군과 스트레스군의 토양흡착수압이 −20kPa인 잎의 경우 스트레스 반응을 보인 픽셀이 72%이었고, −50kPa인 잎에서는 스트레스 반응을 보인 픽셀이 84%로 12%차이 가 났다. 정상군과 스트레스 강도가 다른 시료의 경우 영상의 결과가 명확히 구분되는 것으로 나타나 단파적외선 영상기술이 고춧잎의 수분스트레스 상태를 정량적으로 나타낼 수 있는 기술임을 확인할 수 있었다.
        4,000원
        133.
        2013.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Melamine has been reported to be responsible for kidney stones and renal failure among infants and children. Con-ventional detection methods, High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC), aresensitive enough to detect trace amounts of the contaminant, but they are time consuming, expensive, and labor-intensive. Hyperspectral imaging methods, which combine spectroscopy and imaging, can provide rapid and non-destructive means to assess the quality and safety of agricultural products. In this study, near-infrared hyperspectralreflectance imaging combined with partial least square regression analysis was used to predict melamine particleconcentration in dry milk powder. Melamine particles, with concentration levels ranging from 0.02% to 1% byweight ratio (g/g), were mixed with dry milk powder and used for the experiment. Hyperspectral reflectance imagesin the wavelength range from 992.0nm to 1682.1nm were acquired for the mixtures. Then PLSR models weredeveloped with several preprocessing methods. Optimal wavelength bands were selected from 1454.5nm to 1555.6nm using beta-coefficients from the PLSR model. The best PLSR result for predicting melamine concentration inmilk powder was obtained using a 1st order derivative pretreatment with Rv=0.974, SEP=±0.055%, and F=6.
        4,000원
        135.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 중심파장이 656.3nm에서 반치폭이 약 8nm이고 투과율이 92%인 협대역 H-α imaging 필터를 설계·제작하고, 이 필터의 박막 특성을 연구하고자 한다. 방 법: 전자빔 증착기를 이용하여 Ti3O5/SiO2 다층박막으로 656.3nm 대역투과필터와 Hb600 적외선 차단필터를 만든 후, 분광광도계로 투과율과 대역폭을 확인하였다. SEM사진을 이용하여 적외선차단필터 단면을 관찰하였고, XRD 데이터로부터 박막의 구조를 알 수 있었으며, XPS 분석으로부터 박막 성분을 확인하였다. 결 과: 협대역 H- imaging 필터에서 대역투과필터의 최적조건은 30층, 반사방지막 코팅층은 6층, 적외선차단필터는 32층으로 설계·제작되었다. 제작된 H- imaging 필터의 최대파장피크가 이론치에 비교했을 때 약 0.7nm로 공차가 거의 없는 것을 알 수 있었다. XRD 분석으로 대역투과 필터와 반사방지막 코팅층은 비정질로, 적외선 차단 필터는 결정질으로 코팅되는 것을 확인하였다. SEM 사진에 의해 적외선 차단필터의 코팅 층을 확인하였고, XPS 분석에 의해 대역필터의 가장 바깥층이 SiO2층임을 확인할 수 있었다. 결 론: Ti3O5/SiO2 다층박막을 이용하여 30층의 대역투과 필터와 32층의 적외선차단필터를 제작하여 657nm 중심파장에서 8nm 반치폭을 가지며 투과율은 92%인 협대역 H-α imaging 필터를 제작하였으며, 제작된 필터는 설계치와 거의 비슷한 투과율과 반치폭을 가짐을 알 수 있었다.
        4,000원
        136.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지하 폐광도에 의한 지반침하 지역에서 전기비저항탐사와 시추공영상촬영을 통하여 지하공동의 분포 파악 및 지반 침하의 시간에 따른 변화량 측정을 수행하였다. 전기비저항탐사가 가능했던 연구지역 1에서는 100-150 ohm-meter 정도 낮은 비저항을 가지는 이상대가 관찰되었으며 시추조사와 시추공영상촬영 결과에서 폐갱도를 확인하였다. 연구지역 2는 도로로 피복되어 전기비저항탐사 수행이 불가능하였으나 광맥분포를 고려한 시추조사에서 채굴적 및 폐갱도를 확인하였다. 또한 시추공영상촬영을 43일간 총 6차례에 걸쳐 수행하여 시간에 따른 지하매질의 수직 이동 변위를 측정하였다. 지반침하로 인한 지하매질의 수직이동양상은 하부에서 상부보다 3배 이상 큰 규모로 발생하며 그 지속기간 역시 4배 이상 오랫동안 발생했음을 확인하였다. 효과적인 지하공동 탐지 및 지반침하 작용 모니터링을 위해서는 전기비저항탐사와 시추공영상촬영기법을 활용하는 것이 유용함을 알 수 있었다.
        4,600원
        138.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We demonstrate optical cross-sectional imaging system implemented with high-resolution interferometry and present oral diagnostic imaging results obtained without any physical sectioning. High-resolution interferometry could be performed with utilizing broadband optical source and employment of beam scanning device to high-resolution interferometer constitutes optical imaging system for non-invasive cross-sectional view at real-time. The optical imaging system is implemented with fiber-optic devices for compactness and optical probe head is realized by using single mode optical fiber and miniaturized actuator, which is properly designed for the application to dental imaging. The basic performance of the optical imaging system, for example, such as resolution, imaging depth, and sensitivity is suggested to prove high-resolution optical imaging performance. Feasibility of the developed optical imaging system performance in the application of dental diagnostic is proved with demonstrating non-invasively obtained cross-sectional images. The imaging quality suggested in the images could be applied to assessment of oral diseases and used for alternative imaging modality to X-ray diagnostic method overcoming disadvantage of low-image resolution. The imaging performance enabling real-time image reconstruction also could be exploited as early oral diagnostic apparatus prior to microscopic observation under H&E staining.
        4,300원
        139.
        2013.03 구독 인증기관 무료, 개인회원 유료
        We describe the preparation of superparamagnetic nanoclusters (SNCs) by fine-tuning of the seed Fe3O4 nanoparticle sizes to enhance and their T2 relaxivity can be increased by > 4-fold. Therefore, with 11 nm seed core and PVA coating, SNC-11 exhibit a higher T2 relaxivity than other cluster condition. So fabricating the cluster, seed size is the most important influence the T2 relaxivity. As well as, in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications by targeting affinity. According to the experiments, with 11 nm seed core and PVA coating, SNC-11 exhibited the highest T2 relaxivity of 454 mM-1s-1 due to the strong seed size effect on their magnetic sensitivity, indicating superior magnetic resonance (MR) contrast efficiency. Further in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications.
        4,300원