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        검색결과 18,172

        5661.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to establish the basic data for the active use of the LED light source in the aquaculture industry, the experiment about the behavior of rockfish (Sebastes inermis) corresponding to the LED light was conducted by image analysis. LED lights for the experiment were one red light (wave length: 622 nm; light power: 811 mW) and two green lights (wave length: 518 nm; light power: 648 mW, wave length: 518 nm; light power: 810 mW). Behavior of the rockfish was analyzed using a moving distance (MD5) for 5 minutes where MD5s during the period of feeding were 20.0 m, 19.6 m, 16.3 m and 20.5 m in the ch1, ch2, ch3 and ch4. At the sunrise, mean MD5 of the entire channel about right before and right after were 6.3 m and 8.2 m. At the sunrise, mean MD5s of the entire channel about right before and right after were 13.6 m and 12.0 m. In the ch1, ch2 and ch3, mean MD5s during the period of 24 hours were 13.2 m, 9.6 m and 6.8 m at experiment 1and 5.2 m, 3.8 m and 2.9 m in the experiment 2.
        4,000원
        5662.
        2016.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Appropriate thermo-mechanical properties of nickel-based superalloys are achieved by heat treatment, which induces precipitation and solid solution hardening; thus, information on the temperature ranges of precipitation and dissolution of the precipitates is essential for the determination of the heat treatment condition. In this study, thermal analyses of nickelbased superalloys were performed by differential scanning calorimetry method under conditions of various heating rates of 5, 10, 20, or 40K/min in a temperature range of 298~1573K. Precipitation and dissolution temperatures were determined by measuring peak temperatures, constructing trend lines, and extrapolating those lines to the zero heating rate to find the exact temperature under isothermal condition. Determined temperatures for the precipitation reactions were 813, 952, and 1062K. Determined onset, peak, and offset temperatures of the first dissolution reaction were 1302, 1388, and 1406K, respectively, and those values of the second dissolution reaction were 1405, 1414, and 1462K. Determined solvus temperature was 1462K. The study showed that it was possible to use a simple method to obtain accurate phase transition temperatures under isothermal condition.
        4,000원
        5663.
        2016.05 구독 인증기관 무료, 개인회원 유료
        In this study, natural frequency characteristics of road mower head system are investigated through experiment and numerical analysis. ANSYS workbench 14.5 is used to calculate the frequency analysis in the mower system. Compared the natural frequency using the modal test and computerized analysis. When compared with the experimental results, a 5% error rate has occurred. Simulation results showed that vibration mode shape has directional characteristics, especially to the right and left. These results will be helpful in optimal design for road mower head systems.
        3,000원
        5664.
        2016.05 구독 인증기관 무료, 개인회원 유료
        Since the expectations and demand for higher ride comfort of the customers (driver and passengers) have been dramatically increased, new vehicle model launched on the market have not only better performance and design-wise appealing, but also ride comfort has to be increasingly better than its predecessor. Automotive manufactures have focused on the increasing human thermal comfort. To achieve a high thermal comfort, most manufacturers provide a system for their cars to ensure ventilation, heating and cooling air in the passenger compartment. As results, the influence of the seats and situations in the thermal human comfort are considered. And, the temperature distribution pattern on the human face is acquired at natural condition, both warm condition on which seat is managed around 30℃ and hot condition on which seat is managed around 50℃.
        3,000원
        5665.
        2016.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: It is necessary to find and develop the effective way of intervention for patients with neck pain, since the neck pain is becoming increasingly common throughout the world. To identify the altered motor control in patient with neck pain would be informative to find and develop the effective way of intervention. Objects: The aim of this study was to review literature regarding the altered motor control in patients with neck pain, measured by using surface electromyography (sEMG), ultrasonography, and functional magnetic resonance imaging (fMRI), and to suggest prospective research work on neck pain. Methods: Case-control (neck pain/healthy) studies published between 2004 and 2015 that investigated neck muscle activation, thickness, cross-sectional area, and fat infiltrate were searched in Scopus, PubMed, and ScienceDirect. Twenty-eight articles were included in this study. Results: sEMG, ultrasonography, and fMRI were used complementarily to investigate the altered superficial and deep neck muscle activation, thickness, cross-sectional area, and fat infiltrate in patients with neck pain. They showed the following altered motor control when compared retrospectively with healthy subjects or during specific functional tasks: (1) increased superficial muscle activation, (2) lesser deep muscle thickness, (3) smaller cross-sectional area of the deep muscle, and (4) greater fat infiltrate in deep muscles. In particular, among the women, the office workers showed higher muscle activation of superficial neck muscles during functional tasks, although they did not have neck pain, than those who were not office workers. Conclusion: Studies revealed that patients with neck pain showed an altered motor control when compared with healthy subjects by using various assessment modalities. Understanding this phenomenon would help researchers design an effective intervention for alleviating neck pain or to evaluate the effectiveness of the intervention. In addition, we recommend that female office workers take measures to care for their necks before developing neck pain.
        4,800원
        5666.
        2016.05 구독 인증기관·개인회원 무료
        역삼투 해수담수화 공정에서 막 오염은 생산수량 감소 및 공정의 에너지 소비량 증가를 야기한다. 막간 차압 증가, 생산수량 감소 외에 막 저항 값의 증가는 막 오염 정도를 판단하는 수치로 사용이 가능하다. 특히 막 저항 값 기반의 세정은 막 오염 제어를 통해 역삼투 해수담수화 공정에서 막의 성능 유지 시 사용 가능하다. 이에 본 연구에서는 해수 수질 인자 및 공정 운전 인자에 기반하여 막 저항 값을 예측하는 알고리즘을 제안한다. 알고리즘은 해수담수화 플랜트의 운전 데이터에 기반하여 인자들과 막 저항 값 사이의 관계를 학습하고 검증과정을 거쳐 막 오염 발생 시점을 사전에 예측하는 방식으로 개발되었다. 예측 정확도를 분석하고 개발된 알고리즘의 수정을 통해 예측 정확도 향상을 위한 연구를 진행하였다.
        5667.
        2016.05 구독 인증기관·개인회원 무료
        제조나노물질의 발전으로 이를 이용한 제품들이 늘어남에 따라 상수 내 나노 물질에 대한 잠재 위해성 논란이 제기되어 왔다. 응집과 같은 기존 나노물질 처리 방법에 비해 막 분리법은 2차 오염물이 없고 재사용이 가능하기 때문에 각광받고 있다. 하지만 수계환경 변화로 인한 나노물질의 특성변화에 따른 막 기 반 공정 내 나노물질 거동에 대한 연구는 미미한 실정이다. 따라서 본 연구에서 는 국내에서 사용되고 있는 대표 제조나노물질인 Ag, ZnO, TiO2의 수계 내 유 기물 존재여부에 따른 특성을 분석하고 막기반 상수처리 공정에서의 거동을 평가하고자 하였다. SR-NOM을 대표 자연유기물로 평가하였으며 상수 내 SR-NOM의 유/무에 따른 나노물질들의 응집성 등의 변화가 막기반 공정 결과에 영향을 주었음을 확인하였다.
        5668.
        2016.05 구독 인증기관·개인회원 무료
        역삼투막은 해수의 담수화, 하수 및 폐수 재이용, 산업용수등의 다양한 용도로 널리 사용되고 있다. 하지만 미생물, 콜로이드물질, 스케일, 유기물 등 막의 오염으로 인해 전력비 및 교체비등 운영비가 증가되는 문제를 야기시킨다. 산업 용수 플랜트에서는 역삼투막의 주요 오염 중 하나인 바이오파울링을 저감시키기 위하여 일반적으로 사용하는 염소, 오존 등의 산화성살균제외 CMIT, DBNPA 등 비산화성 살균제도 사용하게 되는데 높은 약품비용로 운영비 증가의 원인이 되기도 한다. 본 연구는 파일럿플랜트를 이용하여 BWRO공정의 자외선 소독 전 처리의 효과검증을 약 1년간 실시하였다. 테스트결과 시기별로 차이가 발생하였 지만 역삼투막의 차압 증가속도를 감소시켜 향후 플랜트 적용 시 운영비 절감에 기여할 것으로 판단된다.
        5669.
        2016.05 구독 인증기관·개인회원 무료
        Novel sulfonated poly(arylene ether) membranes with triazole introduced monomer (SPAE-TM) were synthesized via conventional aromatic condensation reaction. The TM was prepared through “click reaction” with high yield and used as proton transfer moiety to increase proton conductivity of polymer electrolyte membranes (PEMs). To compare chemical, mechanical and thermal stabilities of non crosslinked polymer electrolyte membranes (SPAE-TM10, SPAE-TM20), crosslinked membranes were prepared by thermal crosslinking method (cSPAE-TM10, cSPAE-TM20). The SPAE-TM membranes exhibited excellent thermal stability (Tg = ca. 250°C). The proton conductivities of all membranes were sufficiently high in a wide range of temperatures. The water uptake and swelling ratio of SPAE-TM membranes were successfully suppressed in comparison with SPAE-TM0 membrane.
        5670.
        2016.05 구독 인증기관·개인회원 무료
        제올라이트 분리막은 미세기공이 결정구조에서 비롯되기 때문에 매우 좁고 균일한 미세기공 구조를 갖는 것으로 알려져 있다. 따라서 다공성 지지체 표면에 결함이 없는 균일한 제올라이트 분리층을 안정적으로 형성하기 위한 연구는 매우 중요한 부분이다. 본 연구에서는 다공성 알루미나 지지체 표면에 물/알코올 분리성능이 우수한 투과증발용 NaA, CHA 제올라이트 분리막을 형성시키기 위하여 50-100 nm 크기의 종결정을 도입한 후 수열합성법으로 이차성장시켜 분리막을 제조하였다. 그리고 분리층에 존재하는 비 제올라이트 기공구조(non-zeolitic pore structure)를 상세하게 분석하기 위하여 H2,N2,SF6 등의 단일 가스 투과 거동을 분석함으로써 비제올라이트 기공의 크기를 예측하고자 하였다.
        5671.
        2016.05 구독 인증기관·개인회원 무료
        본 연구에서는 MF/UF/RO/MD와 같은 다양한 종류의 막여과 공정에 대하여 에너지 사용량을 분석하기 위한 기법을 개발하기 위하여 수행되었다. 에너지 흐름 분석을 위하여 공정모사 모델을 개발하였으며 이를 이용하여 각 단계별 유효에너지와 에너지 손실을 계산하였다.
        5672.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although recombinant human Bone Morphogenetic Proteins-2 (rhBMP-2) is clinically useful for bone regeneration, induction of new bone formation requires a large amount of rhBMP-2 in humans. Many investigators have been concentrated efforts on searching materials which enhance the effect of rhBMP-2, and then heparin was found as a potentiating material to rhBMP-2. The purpose of this study were histomorphometrically to analyze the enhancing effect of heparin to rhBMP-2 and to study the mode of actions of heparin to rhBMP-2. Stem cells obtained from rabbit adipose tissue were divided into 4 groups according to heparin concentrations(0, 0.25, 2.5, and 25 μg/ml) with a constant rhBMP-2 concentration(150 ng/ml) and cultured for 2, 4, and 8 days. Naphtol AS phosphate-fast blue BB staining for alkaline phosphatase content and Alizarin red staining for calcium content were performed as time schedules and the morphology and osteoblastic activity were observed closely. 5 μg/ml rhBMP-2 was mixed with the following doses of heparin: 0, 0.25, 2.5, and 25 μg/ml. Each mixture was blotted into 0.5 g of multiporous anorganic bovine bone and was inserted into the critical sized calvarial defects(diameter of 0.8-mm) of rabbits. After 1, 3, and 6 weeks, the harvested tissues were processed and stained using H&E and Masson’s trichrome methods. And the areas of newly formed bone in the grafted material were measured and statistically analyzed. During culture experiment of adipose stem cells with rhBMP-2 and heparin, the degree of osteoblastic differentiation was increased with increasing heparin concentration, but the cellular degeneration was accelerated at higher concentration of heparin as time passed. Consequently the osteoblastic differentiation of progenitor cells were accelerated as the concentration of heparin increased. In addition, the progenitor cells exhibited full differentiations early showing fast degeneration. The higher the concentration of heparin, larger newly formed bone in grafted materials was obtained in initial period. However, the increased amount of the newly formed bone in grafted materials was progressively decreased at the higher concentration of heparin as time passed. In conclusion, the heparin has influence on the osteoinductive effect of rhBMP-2 in the initial stage of bone formation. The use of heparin with rhBMP-2 could offer cheaper, safer, and improve clinical results in grafting procedures.
        4,800원
        5673.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The maxillofacial region is susceptible to damage because facial bone is prominent. The aim of this study is to evaluate the incidence, etiology, seasonal distribution, and patterns of maxillofacial injuries and investigate the percentage of bone fractures on CT scans by patient’s gender and age. Electronic medical records of 1,483 patients who had maxillofacial injuries and visited the Emergency Medical Center of Chonnam National Hospital were evaluated. Age, gender, etiology, seasonal occurrence, frequency of fracture, and the pattern of bone fracture were analyzed by using IBM SPSS Statistics 21 (SPSS Inc., Chicago, IL, USA). Male to female ratio was 2.82:1. The most common causes of injury were falls or collisions (male 40.09%, female 48.2%), followed by traffic accidents and violence. The number of injuries related to sporting accidents, assult, and industrial accidents was higher in male patients than that of female patients. With regard to the seasonal occurrence, 434 cases (29.26%) occurred in the summer, while 306 cases (20.63%) occurred in the winter. In this study, 946 patients (63.79%) were identified to have facture and 537 patients (36.21%) were found to be without fracture on CT scans. The orbital bone (41.38%) was the most commonly fractured in the mid facial structures. The most common fracture site in the mandible was the body of the mandible (23.13%). The patterns of maxillofacial injuries were various based on gender, age, cause of injury, and season.
        4,000원
        5675.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nutritional compositions and physicochemical properties of two aronia varieties (Viking and Nero) cultivated in Chungbuk were investigated. The proximate compositions of Nero and Viking powder were:13% moisture, 0.58% and 0.6% ash, 0.73% and 0.33% crude lipid, 5.47% and 6.51% crude protein, 15.65% and 16.15% crude dietary fiber, and 64.36 and 64.43% crude carbohydrate, respectively. The proximate contents of the aronia samples were not significantly different. Among the physicochemical properties, there was also no significant change in total anthocyanin and antioxidant activity. However, Viking had higher total polyphenol contents and α-glucosidase inhibition activity than Nero. The mineral contents of Al, Fe, Mn, Mg, Ca, Na, K, Cu and Zn in the two aronias were determined. Cu and Zn were not detected in both varieties. With regard to Al, Na and K, Nero was higher than Viking, while Ca was higher in Viking than Nero. From the results, Viking could be suggested to be beneficial for food processing.
        4,000원
        5676.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 숲에서 치유를 경험한 사람들의 체험수기 115편을 질적 분석하여, 숲 치유로 나타나는 핵심 심리현상과 치유의 과정을 추적하기 위하여 수행되었다. 숲 치유 과정에서 경험하는 핵심 심리현상은 <행복감> <편안함> <깨달음> 의 순이었으며, 숲 치유의 과정은 <정서적 변화>를 먼저 경험한 후에 <인지적 변화>와 <행동의 변화>로 이끌어지는 경향을 나타내었다. 숲에서의 치유단계는 시간의 흐름에 따라 <자극단계> <수용단계> <정화단계> <통찰단계> <채움 단계> <변화단계>의 6단계 과정을 거쳤으며, 이러한 과정은 <자연과의 교감> <자신과의 교감> <세상과의 소통>이라 는 기제를 통해 치유가 진전되는 것으로 확인되었다. 기존의 연구는 주로 집단프로그램에 의한 비교 연구와 체험 후의 일시적 상태의 측정으로 결과를 도출하여 효과의 지속성이나 심리적 변화 과정을 검증할 수 없는 한계가 존재하였 다. 본 연구는 기존의 양적 연구의 한계를 보완하여 개인적 심리현상과 치유과정 등을 통합적으로 이해할 수 있는 방법을 제안하였으며, 연구 결과가 산림치유의 메커니즘을 밝히고 산림치유 프로그램 개발이나 실행에 기초자료로 활용될 수 있을 것으로 기대한다.
        4,000원
        5677.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        숲 공간의 영향에 대한 많은 연구들이 있는 반면 시간요인에 대한 연구들은 부족하다. 공간과 시간은 동시적으로 상호간에 영향을 미치기 때문에 공간요인에 의한 영향들은 시간에 의해 변화할 수 있다. 본 연구는 숲에서 보낸 시간의 4가지 요인들(체험, 몰입, 건강지각과 심리내적 인식)에 대한 영향에 초점을 두었으며, 2014년 4월부터 10월까지 설문을 통해 이루어졌다. 설문지는 체험 (LE), 몰입(FL), 건강지각(HP)과 심리내적인식(IPP)으로 구성되었다. 대상자들은 충청남도 이북지역에서 살고 있으며 생태 숲해설 과정이나 생태교육과정에 있는 사람들로 40-70세였다. 이들은 또한 1년에서 20년에 이르는 숲관련 경력을 가지거나 일을 하고 있는 사람들이었다. 체험, 몰입, 건강지각과 심리내적 과같은 요인들은 숲에서 보낸 시간의 영향을 받는 것으로 나타났으며, 이 요인들은 통계적으로 유의한 수준에서 숲에서 보낸 시간에 따라 증가하는 것으로 밝혀졌다. 이 연구는 산림치유프로그램을 기획하는 사람들뿐만 아니라 산림치유를 공부하는 사람들에게도 유용할 것이다. 숲에서 보낸 시간이 체험, 몰입, 건강지각과 심리내적 인식에 영향을 주기 때문에 이 점을 산림치유프로그램에서 고려해야 한다.
        4,000원
        5678.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, car pump market is positively growing in emerging countries as well as advanced countries. A increasing attention is recently drawn to electric vehicle but, still commercialization is expected to take a long time. This research is to study on the performance analysis for change in number of teeth of internal gear oil pump with three different numbers of teeth in the inner gear. After measuring real design features, modeling, velocity distribution and pressure distribution are conducted numerically. Pressure changes and volumetric efficiencies are compared with three different cases in order to analyze the performance for inner gears. Finally, optimum volumetric efficiency is determined with the sequence of case 1, case 2, and case 3.
        4,000원
        5679.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the optimum conditions of solvent extraction type and solvent concentration (60, 70, 80%, v/v), extraction time (30, 80, 130 mins) and extraction temperature (10, 15, 20℃) in order to increase the antioxidant activity of the chia seed. The total polyphenol content and DPPH radical scavenging activity was measured by using response surface methodology (RSM) to establish the optimal conditions. Using ethanol and methanol extractions at extraction concentrations of 60%, and time and temperature of 130 mins and 20℃, the maximum total polyphenol content was 871.00 mg% (R2=0.9507) and 557.70 mg% (R2=0.9784) for ethanol and methanol extraction respectively. Using the same extraction conditions, the maximum level of DPPH radical scavenging activity was 72.14% (R2=0.9675) and 52.79% (R2=0.9524) for ethanol and methanol extraction respectively. The results indicate that ethanol extracts showed a higher antioxidant activity than methanol extracts. The ethanol extraction conditions of response surface analysis (RSA) were affected more by ethanol concentration than by extraction time or temperature. In contrast, the methanol extraction conditions of response surface analysis (RSA) were affected more by extraction time. Based on the RSM, the optimum ethanol extraction conditions were the following: extraction concentration, 63%: time, 100 mins: and temperature, 18℃. The optimum methanol extraction conditions were the following: extraction concentration, 65%; time, 120 mins; and temperature, 16℃.
        4,000원
        5680.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 논문은 비모수적 자료포락분석 기법을 이용하여 감귤농가의 경영효율성을 추정하였다. 추가적으로 커널밀도함수를 이용하여 경영효율성의 분포가 지난 13년간 어떻게 바뀌었는지도 도식화하였다. 연구를 위해 농촌진흥청에서 조사 발표하는 자료를 사용하였다. 분석결과를 보면, 지난 13년간 경영효율성은 시설 감귤농가와 노지 감귤농가 모두에서 상승하는 것으로 나타났다. 이것은 수입농산물이 증가하는 상 황 하에서 감귤농가의 경영효율성이 개선되고 있음을 의미한다. 경영효율성을 순수기술적 효율성과 규 모 효율성으로 분해한 결과, 순수기술적 효율성은 점차 개선되는 반면에 규모 효율성은 악화되는 것으 로 분석되었다. 하지만 여전히 효율성 개선의 여지는 순수기술적 효율성 측면에 있는 것으로 분석되었 다. 순수기술적 효율성은 꾸준히 계속 향상시키되 적정규모를 찾아가는 노력도 병행해야 할 것으로 보 인다.
        4,800원