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        검색결과 206

        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report the effect of plastic deformation on the thermoelectric properties of n-type Bi2Te2.5Se0.5 compounds. N-type Bi2Te2.5Se0.5 powders are synthesized by an oxide-reduction process and consolidated via sparkplasma sintering. To explore the effect of plastic deformation on the thermoelectric properties, the sintered bodies are subjected to uniaxial pressure to induce a controlled amount of compressive strains (-0.2, -0.3, and -0.4). The shaping temperature is set using a thermochemical analyzer, and the plastic deformation effect is assessed without altering the material composition through differential scanning calorimetry. This strategy is crucial because the conventional hotforging process can often lead to alterations in material composition due to the high volatility of chalcogen elements. With increasing compressive strain, the (00l) planes become aligned in the direction perpendicular to the pressure axis. Furthermore, an increase in the carrier concentration is observed upon compressive plastic deformation, i.e., the donorlike effect of the plastic deformation in n-type Bi2Te2.5Se0.5 compounds. Owing to the increased electrical conductivity through the preferred orientation and the donor-like effect, an improved ZT is achieved in n-type Bi2Te2.5Se0.5 through the compressive-forming process.
        4,000원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본고에서는 유형론 연구에 기반하여 가장 전형적인 ‘능격-절대격’ 언어에서 능격동 사가 어떻게 실현되는지 살펴보았고 한·중 능격동사의 판단기준, 유형, 특징을 알아 보았다. 아울러 능격동사와 비슷한 개념인 절대격동사, 비능격동사, 비대격동사들의 정의와 하위분류들을 살펴보고 능격동사와의 차이점을 제시하였다. 그리고 한·중 능 격구문의 실현양상을 제시하고 그 통사적 특징을 분석하였으며 능격구문과 관련된 중간구문, 사동구문, 피동구문의 실현양상, 판단기준, 발전과정을 살펴보았다.
        5,500원
        8.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본고에서는 ‘-더-’와 ‘来着’가 쓰인 용례를 통하여 양자의 범주 소속, 화용적 기능, 통사적 특징, 양태성 등 측면에서 공통점과 차이점을 살펴보았고 또한 하나의 문법 표지가 여러 범주에 걸쳐 나타나는 이유를 문법화의 각도에서 해석하였다. 결론적으 로 ‘-더-’와 ‘来着’는 완료상 표지로써 상이한 서술어와의 결합을 통해 사용 문맥이 확대되고 주관화, 재분석 등 기제로 인하여 인식양태, 증거양태로 문법화 되었다.
        5,500원
        10.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper reports the pH effect of reduced graphene oxide (RGO) colloids on formation of three dimensional (3D) graphene network in nucleate boiling condition, so called boiling method. When nucleated bubbles grow on the hot surface, thin liquid film beneath the bubble is supposed to be dried, in which RGO flakes become close to each other and form a structure. Accordingly, what happened when they are in high particle density would be a key issue for the formation of 3D graphene network. Here, we changed pH and oxidation level of RGO colloids so that their effect was observed on extent of 3D graphene network after boiling method. As pH was lower, i.e. being acid, the RGO colloids become unstable, resulting in 3D structure rather than 2D structure. Similarly, As oxidation level was lower, i.e. being more reduced, it showed a tendency to form 3D structure.
        4,000원
        12.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한국인 학습자에게 적절한 중국어교육문법체계를 설계하기 위한 중간 단계로 중국에서 외국인 학습자를 위해 제정한 『国际大纲(语法:2014)』과 『新HSK大纲(语法:2015)』을 비교분석하여 나타나는 문제점을 찾고, 활용 방안을 모색하여 한국인 학습자를 위한 중국어교육문법체계 설계의 토대 마련에 목적이 있다. 두 요목의 비교분석을 통해서 유사한 문법체계로 상호연계성을 가지고 일부 문법항목의 등급배열, 문법항목의 용어와 기술에서 몇 가지 문제점이 있음을 알 수 있었다. 첫째, 『国际大纲(语法:2014)』과 『新HSK大纲(语法:2015)』의 원칙과 구성 체계는 모두 6등급으로 동일한 문법체계로 연계성을 지녔지만 『新HSK大纲(语法:2015)』이 『国际大纲(语法:2014)』보다 난이도가 높다. 둘째, 한국인 학습자의 특징을 반영하고 등급을 고려하여 비교문, 겸어문, 把자문, 被자문등 누적식순서배열로 배열해야 할 것이다. 셋째, 문법항목의 용어와 기술에서 조동사-능원동사, 존재문-존현문, 被자문-피동문 등 혼용되고, 사용예문도 명확하지 않았다. 이런 문법항목들은 통용성을 지닌 문법항목 용어와 개념이 정확하게 기술할 수 있도록 연구되어야 할 것이다. 이상 『国际大纲(语法:2014)』과 『新HSK大纲(语法:2015)』의 비교분석을 통해 살펴본 문제점과 활용방안을 토대로 한국인 학습자의 중국어교육과 평가가 유기적인 관계를 지닌 교육문법체계가 설계되고 나아가 한국인 학습자를 위한 통용성을 지닌 교육문법요목이 마련되길 기대해 본다.
        6,300원
        13.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study focuses on the fabrication of a WC/Co composite powder from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere for the recycling of WC/Co hardmetal. Mixed powders are manufactured by mechanically milling the oxide powder of WC-13 wt% Co hardmetal scrap and carbon black with varying powder/ball weight ratios. The oxide powder of WC-13 wt% Co hardmetal scrap consists of WO3 and CoWO4. The mixed powder mechanically milled at a lower powder/ball weight ratio (high mechanical milling energy) has a more rapid carbothermal reduction reaction in the formation of WC and Co phases compared with that mechanically milled at a higher powder/ball weight ratio (lower mechanical milling energy). The WC/Co composite powder is fabricated at 900℃ for 6 h from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere. The fabricated WC/Co composite powder has a particle size of approximately 0.25-0.5 μm.
        4,000원
        14.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study explores the space and society of Seorin-bang(瑞麟坊), using the Hanseong-bu family registry from the Gwangmu period to demonstrate the urban organizational units used during the late J oseon dynasty known as Seo(署)-Bang(坊)-Gye(契)-Dong(洞)-Tong(統)-Ho(戶). It seeks to examine how Seorin-bang's space and society changed with time. First, the study offers approximate demarcation for Gye and Dong through spatial verification of Bang-Gye-Dong-Tong-Ho of Seorin-bang in late J oseon Dynasty, whose precise locations were formerly undetermined. Second, it explores the relationships between Bang-Gye-Dong-Tong-Ho which has been widely understood to be hierarchical by previous studies, and classifies the relationship dynamics between Gye and Dong into four types. Third, the study finds that Seorin-bang retained much of its urban structure including roads, plots, and streams and maintained stable population distribution under the Japanese colonial rule, and continuously served as place of residency for many throughout the Gwangmu period. This study has major implications in that it illustrates space and society of Seorin-bang by converting the family registry from the late J oseon Dynasty into spatial data, and observes its changes subsequent to the Japanese colonial rule.
        4,300원
        17.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate the satisfaction with school meal service and the food preference in elementary school students who are in their growth period. A total of 484 students (242 boys) participated and completed a questionnaire survey. The results indicated that the merit of school meals was the highest in ‘balanced diet’. 'Food hygiene' and 'delicious food' were the most important factors in school meals. Most of the students wanted ‘balance between eastern and western foods’ and ‘new dishes’ for the menu of school meals. For the distribution of meals, ‘various kinds of side dishes’ and ‘warmth of dishes’ were mainly required. The main problems of the current environment of school meals were ‘long waiting time’ and ‘noise of the cafeteria’. In satisfaction with the school meal service, the highest satisfactory factor was 'staffs’ cleanliness', following 'arrangement of furniture in cafeteria' and 'nutrition information-providing'; whereas, the lowest factor was 'staffs’ kindness'. In the preference of foods, students preferred ‘white rice’; whereas they did not like ‘bean rice’; and ‘fried rice' was preferred. In side dishes with meat and fish, most of the meats including ‘Tangsuyuk’ and ‘Bulgogi’ were preferred. For fish, ‘fried hairtail’ was preferred; whereas, ‘fried Spanish mackerel’ was not. In case of kimchi, ‘Chinese cabbage kimchi’ and ‘cubed radish kimchi’ were especially preferred. Considering these results, intensive improvement is required to increase school meal satisfaction by understanding the students' needs. An effort to allow the students’ preferences to be reflected in the menu is also needed
        4,000원
        18.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES : Many roadway departure crashes on the freeway interchange are due to the running speed being greater than the design speed. This study aims to ensure a safe and pleasant driving experience for the driver by increasing the superelevation based on the running speed on the highway interchange ramp. METHODS: The mean running speed for each type of ramp is calculated on site survey more than 10 interchanges. Using the mean running speed, we calculated the superelevation and the side friction using the method given in “A Policy on Geometric Design of Highways and Street”(Pages 145-166, 2001). Then, we applied the modified method to the superelevation range. Finally, we ensured safety using the Degree of Safety that is proven by the centrifugal acceleration ratio as suggested by Joseph Craus (1978). RESULTS : The mean running speeds are 50 km/h and 65 km/h when the design speeds are 40 km/h and 50 km/h, respectively. After the application of the new method used in this study, the superelevation will be increased by 9.0% and 10.0% when the mean running speeds are 50 km/h and 65 km/h, respectively. CONCLUSIONS: A higher superelevation can give the driver a more comfortable and safe driving environment. However, the driver needs to be aware of snow and low-temperature conditions.
        4,200원
        19.
        2016.12 KCI 등재 구독 인증기관·개인회원 무료
        목 적 : Fractional Flow Reserve(분획혈류예비력:FFR)은 관상동맥 질환이 있는 환자에서 중간 동맥 협착의 기능적 중요성을 평가하는 방법이다. 이는 관상동맥 협착 부위의 원위부와 근위부 정상혈관의 최대 혈류량의 비율(ΔP)을 말하며 카데터(catheter)가 혈관에 삽입되어 FFR 측정 위치까지 이동되는 방법이 사용된다. 그러나 이 방법은 침습적(invasive)이어서 환자가 불편하고, 신체에 손상을 줄 위험이 있어 비침습적(non-invasive) 방법으로 혈관의 병변(lesions)을 진단 및 평가하는 방법이 주목 받고 있다. 이중 MRI PC-VENC 기법을 이용한 MR-FFR이 그 대안으로 평가되고 있어 MR-FFR 사용에 대한 임상적 유용성을 알아보고자 한다. 대상 및 방법 : 2015년 8월부터 2015년 12월까지 관상동맥의 근위부에 의미 있는 동맥경화반이 관찰되어 FFR측정이 예정된 환자 5명과 건강한 성인 11명에 대해 MR-FFR 검사를 진행하였다. 3.0T MRI 장비를 사용하였고 코일은 phased-array body coil을 사용하였다. CT에서 재구성된 관상동맥 경화반의 범위를 참조하여 coronary LAD MPR(multi planner reconstruction) 영상을 만든 후 혈관의 정상 부위와 동맥 경화반 부위를 포함하여 scan 부위를 결정하여 PC-VENC 영상을 얻는다. 사용된 parameter는 VENC=35-65cm/s in all 3 directions, FA=15˚, cardiac phase=2(70ms/phase), in-plane resolution =0.5-0.6×0.5-0.6mm², slice thickness=3.2mm, scan time은 2-6 min/slice으로 설정하였다. 얻어진 VENC 영상에서 ΔPMR를 구하기위해 MATLAB을 사용하여 각 슬라이스에서 산출된 최대 속도를 적분하여 Navier-Stokes(NS) 공식을 이용하여 data를 산출하였다. 결 과 : Proximal left anterior descending coronary artery(pLAD)에서 stenosis의 area percentage가 증가 할수록 ΔPMR 값을 산출할 수 있는 mmHg 값도 높게 나타났다. 이는 stenosis 정도가 심할수록 분획혈유예비력(FFR) 값이 증가함을 의미하며 기존 FFR을 구하는 방식과 비교했을 때 환자 군(6.40±4.43mmHg), 정상군(0.62±0.49mmHg)에서 유의한 값(p<0.001)으로 나타났다. 기존 FFR 과 MR-FFR 간 결정계수 값은 R2=0.938으로 나타나 MR-FFR 기법과 기존 FFR 측정차가 크게 없음을 알 수 있었다. 결 론 : 현재까지 진행된 연구에서 관상동맥 경화반이 있는 혈관과 정상 혈관 모두에서 기존 FFR 값과 비교했을 때 ΔPMR 분석은 매우 유의한 값을 나타내고 있었다. 이에 따라 다른 종류의 침습적인 방법인 intravascular ultrasound(IVUS), optical coherence tomography (OCT) 등를 이용한 FFR 과 MR-FFR의 비교 연구가 진행되고 있으며 또한 공간적, 시간적 해상도 및 노이즈 감소의 관점에서 기술의 개선과 정확성을 향상시키기 위한 시퀀스 개발도 진행되고 있다. 따라서 비침습적이고 피폭이 없으며 환자에게 유용한 정보가 많은 MR-FFR 측정 방법은 앞으로 임상에서 유용하게 쓰여질 것으로 판단된다.
        20.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the teaching of Chinese as a foreign language, Ba-construction is a difficult grammar items. In the study of Chinese ontology, there are quite a few articles on Ba-construction, and the study of Ba-construction in Chinese as a foreign language teaching has also achieved remarkable results. In recent years, more and more attention has been paid to the teaching of Ba-construction and based on contrastive analysis or language acquisition research. The study of Ba-construction is gradually developed from the background of the cross-linguistic to the background of specific native language . The students' mother tongue has a great influence on Ba-construction learning. Korean is an Altaic language and Chinese is a Sino-Tibetan language. There is a big difference between the two languages. The deep semantic relations of Chinese language are expressed by superficial syntactic relations of Korean language, and The differences between different semantic types and semantic orientations directly affect its correspondence in Korean language. The Ba-construction with different Semantic type have neat corresponding forms in Korean. However, Korean students try to find the similarity between the sentence pattern and native language in the process of Ba-construction acquisition, so make a lot of error sentences. This paper tries to classify Ba-construction into four categories from the perspective of semantic type and the corresponding characteristics of Korean, and discusses the teaching methods of Ba-construction for korean students.
        4,500원
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