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        검색결과 239

        81.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the study was two-fold: to investigate the effects of a group-based book reading plus self-efficacy and outcome expectancy intervention on reading amount, perceived reading ability, reading behavior, and social cognitions and to examine influencing factors of book reading behaviors. Sixty-three sixth graders completed a ten-week book reading intervention in two experimental conditions: one with book-reading activities only and the other with a book-reading plus social cognition intervention. The control group (n=32) studied English in their regular English classes. Questionnaires were administered three times to assess the participants' social cognition, reading behavior, and perceptions of reading English books: right before and right after the intervention, and at eight weeks post intervention. The results showed positive effects of the intervention on reading amount, perceived reading ability, and reading behavior. Of the two experimental groups, the group that had received the book-reading plus social cognition intervention showed more positive results. At eight weeks post intervention, intervention effects on goal efficacy, reading behavior, and attitude toward reading were maintained. Social cognition was found to affect reading amount and behavior for the experimental groups. Research and practical implications are suggested.
        6,600원
        82.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ethylene Tetrafluoroethylene (ETFE) has been widely used in long-span buildings because of its light weight and high transparency. This paper studies the short and long term creep behaviour of ETFE foil. A series of short-term creep and recovery tests were performed, in which the residual strain was observed. A long-term creep test of the ETFE foil was also performed over 110 days. A viscoelastic-plastic model was then established to describe the short-term creep and recovery behaviour. The model contains a traditional multi-Kelvin part and an added steady-flow component to represent the viscoelastic and viscoplastic behaviour, respectively. The model successfully fit the data for three stresses and six temperatures. Additionally, time-temperature equivalency was adopted to predict the long-term creep behaviour of ETFE foil. Horizontal shifting factors were determined from the process of shifting creep-curves at six temperatures. The long-term creep behaviours at three temperatures were predicted. Finally, the long-term creep test showed that the short-term creep test at identical temperatures insufficiently predicted additional creep behaviour, and the long-term test verified the horizontal shifting factors derived from the time-temperature equivalency.
        4,000원
        83.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to suggest the methodology for improving the equity of flow distribution in open channel with multiple outlet, CFD simulations were carried out for actual scale distribution channel being operated in domestic G_WTP(Water Treatment Plant). Also, before and after installing the longitudinal multi hole(diameter=250 mm, 116 holes) baffle suggested by this research, turbidity measurements data were collected for evaluating the effects of hydraulic modification for inlet flow equity. From the both results, total turbidity of settled water was lowered by 30 % and equity of flow distribution was improved about 60 % compared with before hydraulic structure modification.
        4,000원
        84.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A high temperature dilatometer attached to a graphite furnace is built and used to study the sintering behaviorof B4C. Pristine and carbon doped B4C compacts are sintered at various soaking temperatures and their shrinkage pro-files are detected simultaneously using the dilatometer. Carbon additions enhance the sinterability of B4C with sinteringto more than 97% of the theoretical density, while pristine B4C compacts could not be sintered above 91% due to par-ticle coarsening. The shrinkage profiles of B4C reveal that the effect of carbon on the sinterability of B4C can be seenmostly below 1950°C. The high temperature dilatometer delivers very useful information which is impossible to obtainwith conventional furnaces.
        4,000원
        85.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the densification behavior of rhenium alloys including W-25 wt.%Re and Re-2W-1Ta (pure Re) during sintering. The dilatometry experiments were carried out to obtain the in-situ shrinkage in H2 atmo-sphere. The measured data was analyzed through shrinkage, strain rate and relative density, and then symmetricallytreated to construct the linearized form of master sintering curve (MSC) and MSC as a well-known and straightforwardapproach to describe the densification behavior during sintering. The densification behaviors for each material were ana-lyzed in many respects including apparent activation energy, densification parameter, and densification ratio. MSC witha minimal set of preliminary experiments can make the densification behavior to be characterized and predicted as wellas provide guideline to sinter cycle design. Considering the results of linearized form and MSC, it was confirmed thatthe W-25 wt.%Re compared to Pure Re is more easily densified at the relatively low temperature.
        4,000원
        86.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetostrictive actuator is fabricated with epoxy bonding method instead of sputtering method in this study. Fabrication process and experimental measurement method for magneto-mechanical characteristics is proposed. For the design of highly flexible magnetostrictive actuator, TbDyFe epoxy bonding with SU-8 substrate is adopted. The fabrication process for SU-8 substrate and the epoxy bonding is suggested and magnetostrictive behavior is investigated. Variable magnetic field is applied to measure the various magnetostrictive characteristics and magnetostriction is measured with different waves and different magnitude of magnetic field.
        4,000원
        87.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to analyze the accuracy of estrus detection of heat detector and analysis of estrus behavior (mounting and mounted), and the evaluation of conditions required for improving reproductive efficiency in Holstein dairy cows fitted with a estrous detector. The heat detection system consists of estrous detector based on wireless sensor and an electric bulletin board displayed estrus behavior data. When cow mounting other cows, the accuracy of estrus behavior displayed an electric bulletin board were 87.5% (mounting other cows only), 100% (mounting other cows but not standing), 80.0% (mounting other cows with standing for 1∼4 seconds), 90.0% (mounting other cows but not standing for 1∼4 seconds), 80% (mounting other cows with standing for more than 5 seconds) and 90.0% (mounting other cows but not standing for more than 5 seconds). When cow mounted other cows, the accuracy of estrus behavior displayed an electric bulletin board were 100% (mounted other cows but not standing), 100% (mounted other cows with standing for 1∼4 seconds), 100% (mounted other cows but not standing for 1∼4 seconds) and 100% (mounted other cows with standing for more than 5 seconds). Circadian distribution of first observed in estrus were 59.1% (am 8∼pm 6) and 40.9% (pm 6∼am 8). Distribution for the number of estrus behavior were 40.9% (less than 3 times), 36.4% (4∼6 times) and 22.7% (more than 4 times). The conception rates relative to interval from first estrus behavior to insemination for estrus periods were 23.1% (less than 11 hours) and 55.6% (12∼20 hours).
        4,000원
        88.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The objective of this study is to analyze and evaluate the behavior of orthotropic steel bridge deck pavement using three-dimensional finite element analysis and full-scale wheel load testing. METHODS: Since the layer thickness and material properties used in the bridge deck pavement are different from its condition, it is very difficult to measure and access the behavior of bridge deck pavement in the field. To solve this problem, the full-scale wheel load testing was conducted on the PSMA/Mastic bridge deck pavement and the deflection of bridge deck and horizontal tensile strain on top of pavement were measured under the loading condition. Three-dimensional finite element analysis was conducted to predict the behavior of bridge deck pavement and the predicted deflection and tensile strain values are compared with measured values from the wheel loading testing. RESULTS: Test results showed that the predicted deflections are 10% lower than measured ones and the error between predicted and measured horizontal tensile strain values is less than 2% in the critical location. CONCLUSIONS: The fact indicates that the proposed the analysis is found to be accurate for estimating the behavior of bridge deck pavements.
        4,000원
        89.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The researches related to active control systems utilizing superelastic shape memory alloys (SMA) have been recently conducted to reduce critical damage due to lateral deformation after severe earthquakes. Although Superelastic SMAs undergo considerable inelastic deformation, they can return to original conditions without heat treatment only after stress removal. We can expect the mitigation of residual deformation owing to inherent recentering characteristics when these smart materials are installed at the part where large deformation is likely to occur. Therefore, the primary purpose of this research is to develop concentrically braced frames (CBFs) with superelastic SMA bracing systems and to evaluate the seismic performance of such frame structures. In order to investigate the inter-story drift response of CBF structures, 3- and 6-story buildings were design according to current design specifications, and then nonlinear time-history analyses were performed on numerical 2D frame models. Based on the numerical analysis results, it can be comparatively verified that the CBFs with superelastic SMA bracing systems have more structural advantages in terms of energy dissipation and recentering behavior than those with conventional steel bracing systems.
        4,300원
        90.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 수목장에 대한 국민의 관심증대와 수목장 확산을 위한 정부 관계기관의 노력에도 불구하고 수목장 선택 비율은 여전히 저조한 실정이다. 따라서 어떠한 요인이 수목장 선택행동에 영향을 미치는 지를 이해하는 것이 필요하다. 본 연구에서는 Ajzen의 계획행동이론(Theory of Planned Behavior: TPB)을 적용하여 태도(Attitude: ATT), 주관적 규범(Subjective Norm: SN), 지각된 행동통제(Perceived Behavioral Control: PBC) 및 관습(Custom: CUST)과 수목장 선택 의도(Intention: INT)와의 관계를 조사하였다. 2011년 9월중 광주광역시 시민을 대상으로 행정구역별로(동구, 서구, 남구, 북구, 광산구) 비례층화추출법을 이용하여 표본을 선정하였으며 총 412명의 응답이 본 연구를 위해 이용되었다. 구조방정식 모델링 결과, 4개 변수(ATT, SN, PBC, CUST) 모두 수목장 선택의도에 영향을 미치는 것으로 나타났다. 그 영향력은 SN(β=0.459), ATT(β=0.247), PBC(β=0.152), CUST(β=0.102) 순으로 크게 조사되었으며 이들 4개 변수는 수목장 선택의도의 53.0%를 설명하였다. 연구결과에 대한 토의와 수목장 참여의도 및 행동 증진을 위한 몇 가지 방안을 제시하였다.
        4,800원
        91.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수중 이 취미를 유발시키는 대표적인 미량오염물질인 2-methylisoborneal (MIB)과 geosmin(지오스민)의 배제율을 소수성 polyethersulfone (PES) 나노분리막(분획분자량 : 400 Da)을 적용하여 다양한 용액조성에서 관찰하였다. 실험결과 적용된 모든 조건에서 지오스민이 2-MIB보다 다소 높은 배제율을 나타내었다. 용액의 pH 효과를 관찰한 결과 pH가 증가할수록 2-MIB와 지오스민 양쪽 모두 배제율이 증가하는 경향을 나타내었다. 한편, 수중 자연유기물질의 존재는 두 미량유기물질의 배제율을 크게 증가시켰으며 이와 같은 현상은 높은 pH일수록 더욱 뚜렷하게 나타났다. 소수성 분리막을 친수성 TiO2 입자로 표면코팅 시킨 후 배제율을 관찰한 결과 분리막의 표면을 친수화한 후 소수성인 2-MIB와 지오스민의 배제율은 증가하는 경향을 나타내었다. 따라서 소수성 상호작용은 미량유기물질 나노여과 배제율의 중요한 기작 중 하나임을 확인할 수 있었다.
        4,000원
        92.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This purposes of this study were to explain consumer attitudes and purchasing behaviors towards agricultural products using a social network service and to determine the influencing factors such as experience, technology ability, innovation, self-efficacy, perception of usefulness, perception of trust, attitude, purpose of purchase and individual characteristics on them. We analyzed the survey data set, using the ‘logit model’, ‘simultaneous equation model’, and ‘LISREL-Type model’ In this study, the results obtained are summarized as follows. The result for the comprehensive statement of “Trust” was the biggest influence on the purchase agricultural products using the social network service. Therefore, in order to expand agricultural e-commerce using SNS, trust should be to the fore of marketing and publicity campaigns, in order to promote and stabilize the market.
        4,000원
        93.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate the eating habit, body image, and weight control behavior by BMI in Korean female high school students. Data on the 16, 574 subjects was obtained from the sixth Korea Youth Risk Behavior Web-based Survey (2010). Only 52.2% of the subjects had regular breakfast. The rate of skipping breakfast was higher in the underweight group than in the obese group, but the rate of skipping dinner was on the contrary to this. Underweight students had a higher intake frequency of fruits, fast food, instant noodle, and snacks than the obese groups. 3.5% of underweight students considered themselves to be overweight or obese. 53.4% of obese students considered themselves to be overweight. The experience of weight control increased according to BMI, but underweight students considered weight control as an effort to be slimmer. Meal restriction was used more frequently to control weight. The perceived stress level was higher in obese student, especially due to appearance. Therefore, an appropriate, integrated and personalized high school nutrition program should be established for proper body image perception and to develop the self-esteem of female high school students.
        4,200원
        95.
        2012.05 구독 인증기관·개인회원 무료
        Three rice planthoppers, the brown planthopper (Nilaparvata lugens), the white back planthopper (Sogatella furcifera), and the small brown planthopper (Laodelphax striatellus) and the green rice leafhopper (Nephotettix cincticeps) are major homopteran sap-sucking rice pests in Korea. These insect pests commonly have highly modified mouthparts, the stylet bundle, for piercing and sucking. Two pairs of mandibular and maxillary stylets consist of the stylet bundle by interlocking each stylet, which forms the two canals, larger one for food canal and smaller one for salivary canal. Destructive damages result from direct feeding effects (hopperburing) with heavy infestation and/or transmitting virus diseases (Rice stripe virus and Rice black-streaked dwarf virus by L. striatellus and Rice dwarf virus by N. cincticeps). Damage level is closely related to the feeding behavior of sap-sucking insects, so generally honeydew excretion amount on the resistant rice variety is smaller than that on the susceptible. Therefore, the method to measure the honeydew excretion amount has been primarily used as an indirect way to compare the feeding amount between the susceptible and the resistant. On the other hand, the electrical penetration graph (EPG) technique was firstly developed by McLean and Kinsey (1964) to measure voltage changes during piercing and sucking of insect on the plant. Since specific voltage waveforms were identified and it was known that each waveform is commonly related to salivary and feeding behavior of insect stylets in the plant tissue, EPG technique has been used to real-timely and quantitatively measure feeding behavior of piercing and sucking insects on susceptible and resistant rice variety. However, identifying each different waveform distinctly and understanding biological function of each waveform are certainly necessary to analyze feeding behavior in the plant tissue such as phloem sap ingestion. In this study, the stylet penetration behavior of N. lugens, S. furcifera, L. striatellus, and N. cincticeps on rice plants (Oryza sativa) was evaluated through the use of a direct current based electrical penetration graph (DC-EPG). To accomplish this, we classified the EPG waveforms of planthopper group into seven different patterns, np, N1, N2, N3, N4-a, N4-b, and N5, according to their shapes, voltage amplitudes, voltage levels, and frequencies. The N4-b pattern was always preceded by N3 and N4-a, in that order. Continuous honeydew excretion only occurred during the N4-b period, and the honeydew deposited on a filter paper containing ninhydrin reagent during the N4-b period were stained into violet. Based on the location of the stylets in the cross-section of rice tissue and honeydew excretion, the EPG waveforms for the stylet penetration behaviors of the three rice planthoppers were assigned to the following groups; np: non-penetration of stylets, N1: penetration initiation, N2: salivation and stylet movement, N3: an extracellular activity near the phloem region, N4-a: an intracellular activity in phloem region, N4-b: phloem sap ingestion, and N5: activity in the xylem region. Futhermore, we classified the EPG waveforms of the green rice leafhopper, N. cincticeps into seven different patterns, Nc1, Nc2, Nc3, Nc4, Nc5, Nc6, and Nc7 according to their shapes, voltage amplitudes, voltage levels, and frequencies. The Nc6 pattern was always preceded by Nc5 pattern. The Nc6 pattern of the leafhopper was carefully considered as a phloem sap feeding behavior based on regular honeydew excretion. On the other hand, the planthopper group and the leafhopper hardly showed the phloem sap feeding pattern on resistant rice varieties during an EPG-recording. In addition, the duration of the phloem sap feeding patterns was highly decreased on resistant rice varieties relative to susceptible ones. From these results, it is suggested that the phloem sap feeding related patterns are an important parameter to determine resistance of rice plant.
        96.
        2012.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사용후 핵연료내 우라늄 및 초우란원소를 회수하는 파이로프로세싱 공정에서 배출되는 금속염화물계 방사성 폐기물은 높은 휘발특성과 붕규산계 유리와의 낮은 상용성으로 인해 고화처리가 쉽지 않은 폐기 물이다. 이를 위해, 본 연구에서는 고화처리의 한 방법으로 탈염화 반응을 통한 고화체제조 개념을 채택 하였다. 솔젤법을 이용하여 탈염화물질, SiO2-Al2O3-P2O5 (SAP)을 합성하였으며 이를 이용하여 탈염화 반 응거동 반응생성물의 고형화 특성을 조사하였다. LiCl계 폐기물과 달리, LiCl-KCl폐기물의 반응은 두 개 의 온도범위에서 반응이 진행되며, 400℃의 경우에는 LiCl이, 약 700℃에서는 KCl이 주로 반응하는 것으 로 확인되었다. 여러 가지 반응실험을 통하여 LiCl-KCl의 탈염화 반응에 가장 적합한 물질은 SAP 1071 (Si/Al/P=1/0.75/1 in molar)인 것으로 확인되었다. 4가지 종류의 고형화 실험을 통하여 고화체의 bulk shape과 densification은 SAP/Salt의 비에 영향 받는 것을 확인하였다. 제조된 고형화 시료는 Product Consistency Test-A법을 이용하여 기본적인 내구성을 평가하였다. 본 연구는 SiO2, Al2O3, P2O5 로 이루 어진 탈염화 물질을 이용하여 반응특성과 고형화 특성에 대한 기본적인 정보를 제공하였으며, 이와 같은 실험을 통하여, 본 연구에서 제안된 탈염화 고화처리방법이 휘발특성이 높고 기존 유리매질과 상용성이 낮은 금속염화물계 폐기물에 적용이 가능함을 확인하였다.
        4,000원
        97.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        운전자의 인적요인분석을 위한 기초자료를 제공하는 디지털 운행기록계에서는 GPS 속도, 방위각, RPM정보 등 극히 제한된 운행정보만을 기록하여 실제 운전자의 운전행태를 분석하는 데는 많은 한계가 있다. 또한, 현재 상업화가 활발히 이루어지고 있는 차량용 블랙박스는 운전자의 운전행동보다는 차량에 대한 위험사항을 기록하고 있는 방식으로서 운전자의 실제 운전행태를 분석하기에는 많은 문제점을 보이고 있다. 따라서 기존의 교통안전관련 연구들을 살펴보면 인적요인분석에 필요한 운전자의 위험운전분석이 극히 제한적으로 이루어져 있는 현실이다. 이에 본 연구에서는 사업용자동차의 위험운전유형과 각 운전유형을 결정하는 임계치를 이용하여 버스운전자의 운전행태를 분석하였다. 또한, 버스운전자에게 위험운전에 대해 단말기를 통해 실시간으로 경고정보를 자동 제공하여 실시간경고정보에 따른 효과분석을 실시하였다. 운전자들의 행태분석에 대한 해석은 차량의 가속도 센서와 회전 각속도 센서의 종방향 가속도(Ax), 횡방향 가속도(Ay), 회전 각속도(Yaw rate) 등에 대한 분석을 통해 이루어졌다.
        4,000원
        98.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purposes of this study were to identify point makeup purchasing and using behavior according to the personal color awareness. Most women considered their favorite color first when purchasing lipsticks and skin color when purchasing cheek powder or foundation. They considered makeup concept first when applying lipsticks, eye shadows, and cheek powder but skin color applying foundations and manicures. Factors of personal color awareness were preferences & utilization awareness, other’s advice, and direct awareness, and were segmented into PC intermediate group, high PC group, and PC retard group. PC intermediate group were in the late 20’s and the early 30’s, average incomes with high education, and patronized discount stores for point makeups, used fashion color as a criterion when selecting lipsticks, foundations, and manicures, apparel color when applying eye shadows, skin color when applying cheek creams, and preferred imported lipsticks and manicures. High PC group were among unmarried women in the early 20’s, university students, high income households with medium level of pocket money, spent more for point makeup, and patronized department stores and internet shopping mall, used skin color or fashion color as criteria when selecting point makeup, referenced makeup concept when applying point makeup, preferred imported point makeup. PC retard group were among married women in the late 30’s with low education and low income, spent less for point makeup and pocket money, and selected domestic point makeup, used their favorite color as a criterion when selecting point makeups and apparel color when applying lipsticks and cheek creams.
        4,600원
        99.
        2011.10 구독 인증기관·개인회원 무료
        Aphids feed on host plants by penetrating the stems or leaves with stylets. The feeding behavior of aphids consists of probing, penetration, salivation, and sap ingestion. To assess the effects of sound on feeding behavior, we monitored the stylet activity of the green peach aphid, Myzus persicae (Sulzer), using electrical penetration graph (EPG). The use of EPG was critical for determining the stage, frequency, and duration of feeding in aphids. We played back four acoustic stimuli of sine waves with frequencies of 100, 500, 1000, and 5000 Hz to adult aphids. When the sound was treated, the frequencies of probing, penetration, and salivation increased, whereas the duration of sap ingestion decreased. The 100 Hz and 500 Hz was significantly effective to disturb ingestion of phloem sap. The results of EPG revealed that the acoustic stimuli may restrict aphid feeding by disturbing sap ingestion.
        100.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        주각부는 상부의 강구조와 철근콘크리트조 기초의 접합부로써 매우 중요한 부분이다. 현재 국내외 강구조 골조 공사에서 사용되는 주각부의 형식은 크게 구분하여 노출형 주각부 근권형 주각부, 매입형 주각부라고 할 수 있다. 이 중에서 부재의 재사용 및 재활용을 최우선으로 고려한다면 노출형 주각부가 가장 유리하다. 본 연구에서는 이러한 노출형 주각부의 시공 성능 및 역학적 성능을 획기적으로 개선할 수 있는 형태의 강구조 선형상 노출형 주각부를 개발하고, 구조 성능 평가를 위한 탄소성 재하실험을 수행하였다. 그 결과 개발된 신형상 노출형 주각부는 수평 방향과 수직 방향의 시공 오차를 현장에서 간단히 흡수하여 기존 노출형 주각부의 시공 불량을 사전에 방지함으로써 구조 성능을 발휘한다. 또한 에너지 흡수형 고력볼트를 사용함으로써 변형 성능이 증가함을 알 수 있었다.
        4,000원
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