• 제목/요약/키워드: differential form

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중학생의 영토정체성에 관한 연구 -스케치맵에 나타난 영토, 국경, 이웃한 나라에 대한 인식을 바탕으로- (A Study of Middle School Students' Perception regarding Territorial Identity: Assessing their Freehand Sketch Maps of Territory, National Border, and Neighboring Countries)

  • 전보애
    • 대한지리학회지
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    • 제47권6호
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    • pp.899-920
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    • 2012
  • 본 연구는 탈영토화 시대의 영토교육을 위한 기초자료로써 학생들의 영토 인식을 이해하고 진단하는 데 목적이 있다. 학생들이 그린 스케치맵을 통해 영토의 형태와 국경, 지리적 위치, 그리고 국경을 마주하고 있는 국가들에 대한 인식이 어떻게 나타나는 지 알아 보았다. 또한, 북한과 DMZ, 독도에 대한 인식을 통해 다른 국가나 우리나라에 대한 가치, 태도, 감정이 간접적으로 어떻게 영토지도에 표현되었는지를 분석하였다. 본 연구는 기존의 연구들과 달리 스케치맵과 사후 인터뷰를 통한 정성적인 분석방법을 채택하였다. 스케치맵 방식은 학생들이 영토에 대한 자신의 생각을 자유롭게 표현하도록 함으로써 구조화된 설문지를 이용하는 방식보다 영토정체성에 대한 맥락과 담론을 보다 풍부하게 제공한다. 이를 통해 67개의 코드와 626개의 인용구를 포함한 코드리스트를 추출하였다. 정성적 분석에서 도출한 변인들 간의 상관관계나 학생들의 성적과의 비교 분석을 위해 SPSS를 이용한 정량적인 분석을 실시하였다. 분석 결과를 토대로 지리교육의 영역에서 바람직한 영토교육의 모형과 교수-학습 자료의 개발을 위한 논의를 제시하였다.

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Characterization of aluminized RDX for chemical propulsion

  • Yoh, Jai-ick;Kim, Yoocheon;Kim, Bohoon;Kim, Minsung;Lee, Kyung-Cheol;Park, Jungsu;Yang, Seungho;Park, Honglae
    • International Journal of Aeronautical and Space Sciences
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    • 제16권3호
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    • pp.418-424
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    • 2015
  • The chemical response of energetic materials is analyzed in terms of 1) the thermal decomposition under the thermal stimulus and 2) the reactive flow upon the mechanical impact, both of which give rise to an exothermic thermal runaway or an explosion. The present study aims at building a set of chemical kinetics that can precisely model both thermal and impact initiation of a heavily aluminized cyclotrimethylene-trinitramine (RDX) which contains 35% of aluminum. For a thermal decomposition model, the differential scanning calorimetry (DSC) measurement is used together with the Friedman isoconversional method for defining the frequency factor and activation energy in the form of Arrhenius rate law that are extracted from the evolution of product mass fraction. As for modelling the impact response, a series of unconfined rate stick data are used to construct the size effect curve which represents the relationship between detonation velocity and inverse radius of the sample. For validation of the modeled results, a cook-off test and a pressure chamber test are used to compare the predicted chemical response of the aluminized RDX that is either thermally or mechanically loaded.

심혈관계를 포함한 인공심장의 모델링 및 컴퓨터 시뮬레이션 (Modeling and Simulation of the Total Artificial Heart with Cardiovascular System)

  • 박준우;박성근;최종훈;조영호;최재순;안재목;민병구
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1998년도 추계학술대회
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    • pp.249-250
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    • 1998
  • In this study, we modeled moving-actuator type Total Artificial Heart (TAH) with cardiovascular system as a form of electric circuit. The bronchial circulation, important for the imbalance between the left cardiac output and the right one, was considered and added to the model. In the model, the relations of hemodynamic variables, just as blood pressures, volumes, or flow rates of each part of body, can be expressed as simultaneous first order ordinary differential equations. To solve the equations by the numerical analysis, Runge-Kutta forth order approximation method was adopted. The simulation software (SimTAH), implemented in C++ as a window-based application program, was developed to display the hemodynamic variables and to receive control inputs from users. SimTAH was evaluated by comparison of the simulation results with the results of mock-circulation tests, in vitro.

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Development of a Data Reduction Algorithm for Optical Wide Field Patrol (OWL) II: Improving Measurement of Lengths of Detected Streaks

  • Park, Sun-Youp;Choi, Jin;Roh, Dong-Goo;Park, Maru;Jo, Jung Hyun;Yim, Hong-Suh;Park, Young-Sik;Bae, Young-Ho;Park, Jang-Hyun;Moon, Hong-Kyu;Choi, Young-Jun;Cho, Sungki;Choi, Eun-Jung
    • Journal of Astronomy and Space Sciences
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    • 제33권3호
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    • pp.221-227
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    • 2016
  • As described in the previous paper (Park et al. 2013), the detector subsystem of optical wide-field patrol (OWL) provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time) data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.

스프링클러헤드 감열부의 열적 특성에 관한 연구 (An Investigation on the Thermal Characteristics of Heat-Responsive Element of Sprinkler Head)

  • 유우준;문효준;염문천;유홍선
    • 한국화재소방학회논문지
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    • 제26권3호
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    • pp.79-84
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    • 2012
  • 본 연구에서는 국내외 스프링클러헤드 감도시험 기준에 적용하고 있는 반응시간지수(RTI, Response Time Index)를 사용하여 대류항과 전도항 그리고 시간 변화량을 고려한 감열부의 열전달 현상을 해석적으로 분석하였다. 원형 실린더 형상을 갖는 감열부의 열적 특성을 분석하기 위해서 비제차 2차 편미분 형태의 에너지 방정식을 사용하여 감열부 표면의 온도가 일정하고 대칭(Symmetric)인 경계조건을 적용하여 시간 증가에 대한 감열부의 반지름 방향 온도분포를 구하였다. 그 결과 본 연구의 감열부 열적 특성에 관한 분석 기법은 스프링클러헤드의 감도시험 및 감열부의 설계를 위한 자료의 활용이 가능할 것으로 판단된다.

피부온을 기반으로 한 가전제품의 감성 평가 프로토콜 수립을 위한 문헌 조사 (A Literature Review for an Emotion Evaluation Protocols Based on Skin Temperature for Home Appliances)

  • 전은진;이승훈;김희은;유희천
    • 한국의류산업학회지
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    • 제22권2호
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    • pp.240-249
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    • 2020
  • This study reviews studies that used skin temperature in order to establish an emotion evaluation protocol based on skin temperature for home appliances. A survey of skin temperature evaluation papers was conducted by the following five stages: (1) keyword search, (2) title screening, (3) abstract screening, (4) full paper screening, and (5) relevance evaluation. Selected papers were reviewed for: purpose, recruitment criteria of participants, the number of participants, apparatus, procedure, measures, analysis methods, and major findings. Thermistor sensors and thermography are used for the measurement of skin temperature. Skin temperature sensors are attached to 4 - 10 locations on the body and their mean of skin temperature is calculated by Ramanatan's 4-point or Hardy & Dubois's 7-point method. Semantic differential (SD) method and thermography measuring facial surface temperature have been used for emotion evaluation. The SD method provides a set of adjective pairs related to a product and evaluates changes in emotion from the use of the product. The range of facial surface analyzed is defined in the thermal image and temperature changes before and after the evaluation are analyzed. The evaluation items of home appliances include form, color, material, aesthetics, satisfaction, novelty, convenience, pleasantness, and excellence. Many existing emotion studies using skin temperature do not apply physiological and psychological methods. This study provides basic data to establish a skin temperature and emotion evaluation protocol by examining literature for skin temperature and evaluation of sensitivity.

Hormonal Requirements Induced Different Regeneration Pathways in Alhagi graecorum

  • Hassanein, A.M.
    • Journal of Plant Biotechnology
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    • 제6권3호
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    • pp.171-179
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    • 2004
  • Hormonal requirements inducing different regeneration pathways with particular emphasis on somatic embryo-genesis in Alhagi graecorum were studied. While combination of 0.5 $\mu{M}$ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.5 $\mu{M}$ 6-benzylaminopurine (BAP) and 5 $\mu{M}$ 1-naphthaleneacetic acid (NAA) in MS medium induced callus formation and callus maintenance from internodal explants, each alone or in combination with other induced distinct regeneration pathway. Adventitious bud formation was induced on MS medium supplemented with 2.5 $\mu{M}$ BAP. It was improved when 2.5 $\mu{M}$ BAP was used in combination with 5 $\mu{M}$ NAA. MS medium containing 0.5 $\mu{M}$ 2,4-D or 5 $\mu{M}$ NAA induced the formation of abnormal direct somatic embryos. While increase of 2,4-D concentration (1.125-9) resulted in the formation of viable embryogenic mass, increase of NAA did not change its effect. NAA should be used in combination with 2,4-D even at low concentration (0.5 $\mu{M}$) to form embryogenic mass. In A. gaecorum, the role of 2,4-D as trigger of somatic embryogenesis and BAP as trigger of adventitious bud formation was deduced, but for maximum yield certain auxin-cytokinin ratio should be applied. Embryogenic masses characterized by high water content, low peroxidase activity, and low number of peroxidase and glutamate oxaloacetate transaminase bands in comparison with calli obtained under conditions stimulating adventitious bud formation. The resulted differential gene expression, which could be detected by native-PAGE patterns, could be used as marker for organogenic pathway in A. graecorum.

Studies on the Effect of Silicon Nutrition on Plant Growth, Mineral Contents and Endogenous Bioactive Gibberellins of Three Rice Cultivars

  • Jang, Soo-Won;Hamayun, Muhammad;Sohn, Eun-Young;Shin, Dong-Hyun;Kim, Kil-Ung;Lee, In-Jung
    • Journal of Crop Science and Biotechnology
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    • 제10권1호
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    • pp.45-49
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    • 2007
  • Silicon is one of the key elements for healthy growth and development in rice crops. We analyzed the effect of silicon(Si) on some growth parameters, plant mineral contents, and bioactive gibberellins in three rice cultivars. Silicon was applied at the rates of 0 kg/0.1ha(control), 40 kg/0.1ha, and 80 kg/0.1ha throughout the course of experiment. Plant growth parameters were enhanced by the application of elevated Si, though plant height and culm length were more favorably affected than the respective dry weights. The plant mineral contents analyzed also increased in treatments where Si was applied without potassium, demonstrating that Si application promotes the absorption of these minerals in rice crops. The endogenous gibberellins measured in our study showed that $GA_1$ is the only bioactive GA form present in rice seedlings. The endogenous $GA_1$ and its precursor $GA_{20}$ contents increased after Si application. However, this increase in endogenous $GA_1$ and $GA_{20}$ contents, and plant growth parameters were different according to the rice cultivars. Our results indicate that Si is a beneficial element in rice nutrition and that different cultivars of Oryza sativa show differential responses to Si nutrition in terms of their growth and development.

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다전극 산소 센서를 이용한 고분자 막의 산소 투과도 측정 장치 연구 (A Study on the Apparatus for Measuring Oxygen-Permeability of Membranes with a Multi-Electrode Oxygen Sensor)

  • 정일손;정재칠;김태진
    • 센서학회지
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    • 제21권3호
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    • pp.229-234
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    • 2012
  • The existing permeability measurements based on pressure differential between the polymer membrane that is permeable to measure the amount of oxygen used, but these methods must be kept in a vacuum, and the measurement of the membrane with low permeability in the membrane is too time consuming. In recent years by using electrochemical method polymer membrane currents caused by the amount of oxygen is a measure of how much is used. In this study, apparatus consisting of one anode and six cathodes for multi-oxygen permeability tester used the same number of membranes produced by electrochemical oxygen permeation characteristics. In this study, one silver/silver chloride anode electrochemical method with a hexagonal sensor to put various kinds of polymer membranes with the six oxygen permeability for simultaneous measurement in real-time systems. Six cathodes (Pt), and one of the coil-shaped anode (Ag/AgCl) to form a hexagonal one of the polarographic oxygen sensor in a single measurement system by six sensors. Each sensor for making hexagonal specificity of the sensor to compensate for the conditions obtained in a pure nitrogen gas and pure oxygen gas conditions. With this study, self-developed hexagonal sensor capable of measuring sensors and oxygen permeability tester, for a multi-six different oxygen permeability characteristics of the membrane measured at the same time.

Process Optimization for Preparing High Performance PAN-based Carbon Fibers

  • Yun, Jeong-Hyeon;Kim, Bo-Hye;Yang, Kap-Seung;Bang, Yun-Hyuk;Kim, Sung-Ryong;Woo, Hee-Gweon
    • Bulletin of the Korean Chemical Society
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    • 제30권10호
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    • pp.2253-2258
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    • 2009
  • wet spun polyacrylonitrile (PAN) fiber precursors. The process variables chosen were treatment temperature, applied tension in stabilization process. The temperature profile of the stabilization was set on the basis of exothermic peaks of the differential scanning calorimetry (DSC) result. Both tensile strength and modulus increased with holding at onset temperatures of the exothermic peaks for extended duration, and with a higher heating rate up to the onset temperatures at a given applied tension among the experimental conditions. The increase in load monotonously increased the tensile modulus, on the other hand, the tensile strength was maximum at the load of 15 mg/filament (T15). The load 20 mg/ filament (T20) was considered to be exceeded to form oriented crystalline structure, possibly introducing more defects in the fiber than under load of T15. The sample CP3-T15 O5 H30 showed the best tensile properties among the samples experimented whose tensile properties are compatible with the commercialized grade of general purpose carbon fibers even at low carbonization temperature such as $800\;{^{\circ}C}$ (the carbonization temperature in the commercial process. 1300∼$1500\;{^{\circ}C}$).