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        검색결과 132

        61.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        수생태계에서 외래종의 문제는 국내뿐만 아니라 국제적으로도 많은 문제를 야기하고 있다. 배스의 경우 높은 포식압으로 수생태계 내에서 상당한 교란 요인으로 작용하고 있으며, 환경부에서 위해종으로 선정되어 관리 받고 있다. 본 연구에서는 위해종인 배스가 국내토착종인 붕어의 개체군에 미치는 영향을 파악하였다. 조사는 총 7지역의 저수지에서 시행하였으며, 배스의 유무에 따라 붕어의 길이분포와 길이무게 상관관계를 분석하였다. 연구결과 배스가 서식하는 지역의 붕어 개체군은 1년생 이하 치어의 비율이 전반적으로 높지 않았고 오히려 2년생 이상의 큰 개체의 비율이 높게 나타났다. 반면 배스가 서식하지 않는 호소의 붕어 개체군은 1년생 이하의 비율이 높게 나타나 일반적인 성장 패턴을 보였다. 또한 배스의 직접적인 먹이가 되는 1년생 이하의(160 mm 이하) 붕어개체를 대상으로 길이-무게 상관관계 분석 결과 배스가 서식하지 않는 호소에서 매개변수 b값이 2.909, 배스가 서식하는 호소에서는 매개변수 b값이 3.100로 나타나 배스가 존재하는 환경에서 붕어의 무게가 상대적으로 더 빠르게 증가하는 것을 확인할 수 있었다. 따라서 배스의 포식에 직접적으로 영향을 받는 호소내 개체군이 생존을 위해 상대적으로 빠른 성장 전략을 사용한 것으로 사료되었으며, 이와 같은 현상은 붕어뿐만 아니라 국내 토착하는 다른종에서도 유사하게 확인될 것으로 판단된다.
        4,000원
        62.
        2013.09 구독 인증기관·개인회원 무료
        탄산칼슘 형성 미생물은 요소(CO(NH2)2)의 가수분해를 통해 탄산염이온(CO3 2-)을 생성하고, 분해된 탄산 염이온은 칼슘이온(CO3 2+)과 결합하는 탄산칼슘형성작용(Microbially Induced Calcite Precipitation)을 하는 것으로 알려져 있다. Muynck et al.(2008)은 탄산칼슘(CaCO3) 형성 미생물을 콘크리트에 적용하여, 자가 균열보수 및 강도 증진 효과의 가능성을 언급하였다. 이러한 탄산칼슘 형성 미생물을 콘크리트 도로포장에 적용할 경우, 경화 시 발생하는 미세균열을 방지하고, 초기강도 증진효과를 얻을 수 있으며, 장기강도 및 공용성을 증진시킬 수 있을 것으로 예상된다. 따라서 본 연구는 탄산칼슘 형성 미생물을 콘크리트 포장에 적용하기 위한 기초연구로서, Lysobacillus sphaericus종의 탄산칼슘형성 미생물을 적용시킨 시멘트 모르타르에서 탄산칼슘 형성량과 초기강도 발현을 확인하였다. 이를 위해, SEM 촬영 및 EDS 분석을 실시하여 탄산칼슘 형성능력을 비교하였고, 3일, 7일 28일 압축강도 시험을 통해 초기강도를 측정하였다. SEM(Scanning Electron Microscope) 촬영 결과, 미생물에 의해 탄산칼슘이 형성된 공시체의 단면은 그림 1(a)와 같이 탄산칼슘 결정들에 의해 거칠게 나타난 반면, 탄산칼슘 미생물이 주입되지 않은 일반 시멘트 모르타르의 표면은 그림 1(b)와 같이 비교적 매끄러운 것으로 확인되었다. EDS(Energy Dispersive x-ray Spectroscopy) 분석을 실시하여 탄산칼슘 형성량을 비교한 결과, 미생물을 적용한 시멘트모르타르 공시체에서 탄산칼슘 질량이 16.7% 증가함이 확인되었다. 그리고 미생물에 의해 생성된 탄산칼슘이 압축강도에 미치는 영향을 분석한 결과, 탄산칼슘 형성 미생물을 적용시킨 시멘트 모르타르의 경우 일반 시멘트 모르타르에 비해 강도가 48.1% 증가하는 것으로 나타났다.
        63.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this research was to suggest a category and level of national examination for dietitian's license and provide basic data for the development of national examination question by analyzing the current states on the curriculum of national examination for the dietitian's license and correlation with the current states on curriculum and national examination for the dietitian's license. The higher the current states on curriculum, the lower absentee rate and failing rate of the national examination for the dietitian's license. The higher the current states on curriculum, the higher pass rate of the national examination for the dietitian's license. Also, the current states on curriculum were positive relationship with correct answer rates. The higher the educational system, the higher the current states on curriculum. The educational system was negative relationship with the current states on curriculum of ‘public health’, ‘advanced nutrition’, ‘food science’, ‘principles of culinary’, and ‘food sanitary law (p<0.05)’. The correct answers rates of ‘institutional foodservice’ were significantly positive relationship with the current states on curriculum of ‘institutional foodservice (p<0.01)’, ‘foodservice organization (p<0.01)’, ‘food sanitation (p<0.05)’, and ‘practice in foodservice institutions (p<0.01)’. The pass rate was significantly positive relationship with the correct answer rates of ‘institutional foodservice (p<0.01)’, ‘physiology (p<0.01)’, ‘biochemistry (p<0.01)’, ‘food sanitary law (p<0.01)’, ‘food science and preparation (p<0.05)’, ‘nutrition education (p<0.01)’, ‘nutrition (p<0.01)’, and ‘total score (p<0.05)’.
        4,000원
        64.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to develop measures for establishing and enforcing legal nutrition labeling for Takju based on results from consumer awareness surveys, statistical model development, and evaluation of nutrients. The statistical model developed with consumer survey results showed that consumers would like to know the nutrients they intake from drinking Takju, as their awareness about Takju was low. Specifically, consumers would like to see information regarding alcohol content, calories, carbohydrates, and saccharides on the label. Structural equations from the research model showed that consumers who had some knowledge of Takju also had positive thoughts of the nutrition fact labels for Takju. Evaluation of nutrients in Takju showed that the starch sources and other ingredients used in Takju fermentation did not influence nutrient facts, and nutrient concentrations also varied among the different Takju. In addition, this research suggests methods for consumers to make reasonable selections and to inform them of the nutrition fact labeling for Takju. Benners and pop-up were manufactured to promote voluntary participation of companies and to provide nutrition facts from Takju. Eventually, a measure was suggested to establish and enforce nutrition labeling, using results from consumer and nutrient surveys of Takju.
        4,000원
        66.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유채 품종에서 황 공급수준이 황산염 흡수 및 동화에 미치는 영향을 구명하고자 어린 잎과 성엽조직에서 ATP sulfurylase (ATPs), SO42- 흡수, 글루타치온 함량을 분석하였다. 본 실험에서 10가지 유채 품종들 (Mosa, Capitol, Saturnin, Akela, Pollen, Mokpo, Youngsan, Tamra Colosse 그리고 Naehan)은황 공급수준에 따라 몇 가지 황산염 흡수와 동화 능력이 다르게 나타났다. 황 결핍 조건에서 모든 품종의 ATP sulfurylase (ATPs) 활력은 늙은 잎에 비해 어린 잎에서 높게 나타났으며, 글루타치온 함량은황 공급수준이 감소함에 따라 어린 잎에서 많이 증가하였다. 이러한 결과들은 유채 품종별 황 결핍조건에서 황을 이용하는 능력이 다르다는 것을 잘 보여주었다.
        4,000원
        68.
        2011.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Highly textured Ag, Al and Al:Si back reflectors for flexible n-i-p silicon thin-film solar cells were prepared on 100-μm-thick stainless steel substrates by DC magnetron sputtering and the influence of their surface textures on the light-scattering properties were investigated. The surface texture of the metal back reflectors was influenced by the increased grain size and by the bimodal distribution that arose due to the abnormal grain growth at elevated deposition temperatures. This can be explained by the structure zone model (SZM). With an increase in the deposition temperatures from room temperature to 500˚C, the surface roughness of the Al:Si films increased from 11 nm to 95 nm, whereas that of the pure Ag films increased from 6 nm to 47 nm at the same deposition temperature. Although Al:Si back reflectors with larger surface feature dimensions than pure Ag can be fabricated at lower deposition temperatures due to the lower melting point and the Si impurity drag effect, they show poor total and diffuse reflectance, resulting from the low reflectivity and reflection loss on the textured surface. For a further improvement of the light-trapping efficiency in solar cells, a new type of back reflector consisting of Ag/Al:Si bilayer is suggested. The surface morphology and reflectance of this reflector are closely dependent on the Al:Si bottom layer and the Ag top layer. The relationship between the surface topography and the light-scattering properties of the bilayer back reflectors is also reported in this paper.
        4,000원
        69.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        가뭄 스트레스 조건에서 마이코라이자의 접종이 질소의 흡수와 동화에 미치는 영향을 구명하기 위해 마이코라이자를 접종한 처리구와 접종하지 않은 처리구에서 수분처리 7일간 총 , 흡수된 로부터 아미노산과 단백질로 합성된 15N 함량을 각각 분석하였다. 정상 관수구에서는 전 조사항목에서 마이코라이자 접종에 대한 유의적인 효과가 나타나지 않았다. 총 함량은 가뭄 스트레스에 의해 마이코라이자 접종구 및 비접종구에서 각각 13.8%, 28.5% 감소하였다. 함량은
        4,000원
        70.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        화이트 클로버에서 마이코라이자 접종이 가뭄스트레스와 관련된 생리학적 요인들을 조사하기 위하여, 마이코라이자 접종 (AM) 또는 비접종구에서 정상관수 (WW) 또는 가뭄 스트레스 처리 (DS)하여 7일동안 주기적으로 잎 수분포텐셜, 상대수분함량, 건물중, 광합성효율, 증산, 기공전도성, 프롤린 및 암모니아 함량을 각각 측정하였다. 모든 조사항목에서 정상적인 관수조건 (대조구)에서는 전 시험기간 중 변화가 매우 적었으며, 마이코라이자 접종에 의한 변화도 매
        4,000원
        71.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine purchasing behavior and satisfaction for imported processed snacks of mothers with preschool children and to provide nutrition education information for mothers. 81.4% of the respondents often purchased imported processed snacks and the main reason (51.0%) for purchasing imported processed snacks was preference of children. A total of 58.0% of the respondents purchased imported processed snacks at a large-scale discount store. 41.9% of the respondents purchased imported dairy products everyday, and 24.8% of them purchased the products once per week. The percentage of not purchasing at all was very high for imported confectionary, jelly and candy, nuts, and drinks. The food additive checking score was very high when purchasing imported processed snacks. The graduate school group and unemployed mothers checked significantly more often for food additives (p<0.05). The taste satisfaction score was very high, and employed mothers were satisfied with taste significantly more than unemployed mothers. Nutrition education using imported processed food labeling should be performed, and quality management before importing processed food should be carried out.
        4,000원
        72.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from 25˚C to 500˚C, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at 500˚C, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the Jsc values from 9.94 mA/cm2 for the flat Ag back reflector at 25˚C to 13.36 mA/cm2 for the rough one at 500˚C. A conversion efficiency of 7.60% (Voc = 0.93, Jsc = 13.36 mA/cm2, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.
        4,000원
        73.
        2010.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Silicon quantum dots (Si QDs) in a superlattice for high efficiency tandem solar cells were fabricated by magnetron rf sputtering and their characteristics were investigated. SiC/Si1-xCx superlattices were deposited by co-sputtering of Si and C targets and annealed at 1000˚C for 20 minutes in a nitrogen atmosphere. The Si QDs in Si-rich layers were verified by transmission electron microscopy (TEM) and X-ray diffraction. The size of the QDs was observed to be 3-6 nm through high resolution TEM. Some crystal Si and -SiC peaks were clearly observed in the grazing incident X-ray diffractogram. Raman spectroscopy in the annealed sample showed a sharp peak at 516 cm-1 which is an indication of Si QDs. Based on the Raman shift the size of the QD was estimated to be 4-6 nm. The volume fraction of Si crystals was calculated to be about 33%. The change of the FT-IR absorption spectrum from a Gaussian shape to a Lorentzian shape also confirmed the phase transition from an amorphous phase before annealing to a crystalline phase after annealing. The optical absorption coefficient also decreased, but the optical band gap increased from 1.5 eV to 2.1 eV after annealing. Therefore, it is expected that the optical energy gap of the QDs can be controlled with growth and annealing conditions.
        4,000원
        74.
        2010.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper investigates the dependence of a-Si:H/c-Si passivation and heterojunction solar cell performances on various cleaning processes of silicon wafers. It is observed that the passivation quality of a-Si:H thin-films on c-Si wafers depends highly on the initial H-termination properties of the wafer surface. The effective minority carrier lifetime (MCLT) of highly H-terminated wafer is beneficial for obtaining high quality passivation of a-Si:H/c-Si. The wafers passivated by p(n)-doped a-Si:H layers have low MCLT regardless of the initial H-termination quality. On the other hand, the MCLT of wafers incorporating intrinsic (i) a-Si:H as a passivation layer shows sensitive variation with initial cleaning and H-termination schemes. By applying the improved cleaning processes, we can obtain an MCLT of 100μsec after H-termination and above 600μsec after i a-Si:H thin film deposition. By adapting improved cleaning processes and by improving passivation and doped layers, we can fabricate a-Si:H/c-Si heterojunction solar cells with an active area conversion efficiency of 18.42%, which cells have an open circuit voltage of 0.670V, short circuit current of 37.31 mA/cm2 and fill factor of 0.7374. These cells show more than 20% pseudo efficiency measured by Suns-Voc with an elimination of series resistance.
        4,000원
        75.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The ubiquitous, which is developed for human's convenience, uses the concept of situation awareness that communicates with computer and performs a certain work without user's recognition. In order to collect the information of situation, many devices are required. Also, in the condition of ubiquitous middleware, priority is given to effective controls of various devices. There are many devices for collecting the information of situation awareness such as sensor, RFID, etc. Among them, in the use of RFID, the researcher performed the experiment, in which multiple readers were used depending on the necessity of awareness information, and found the problem of intervention between readers occurring when multiple readers are used. The paper handles the problem of intervention causing from using multiple readers and suggests middleware design module using session manager to solve the problem.
        4,000원
        76.
        2008.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This purpose of this study was to develop a functional muffin by adding yam powder in the shape of a muffin as a partial surrogate for wheat flour. The yam has been found to be effective for liver and kidney function, as well as the digestion of protein, since it produces glucuronic acid in the body. Therefore, the purpose of this study was to determine the optimal mixing conditions of yam muffins by adjusting the amounts yam powder, butter, and sugar. The mixing conditions for the yam muffins included 3 categories: yam powder (X1), sugar (X2), and butter (X3) by Central Composite Design (CCD) which was optimized by Response Surface Methodology (RSM). The effects of the three variable additions on muffin quality were examined via physical and chemical experiments, such as the analysis of texture (hardness, cohesiveness, springiness, gumminess), coloration (lightness, redness, yellowness), and height. Lastly, we performed a sensory test, which revealed significant findings for gumminess, color, appearance, flavor, softness (p〈0.05), redness, and overall quality (p〈0.01). Consequently, the optimal mixing rate which best satisfied the sensory items were 34.35g of yam powder, 80.15 g of sugar, and 80.55 g of butter.
        4,000원
        77.
        2008.02 구독 인증기관 무료, 개인회원 유료
        This study is to evaluate control effects of separation wall by surveying water quality and sewer overflows during dry and wet periods in combined sewer and separated sewer systems. Ravine water from the combined Seokgyo outfall with the separation wall was separated about four times larger than sewage flow during dry periods. The water quality of the combined Seokgyo outfall with separation wall during dry periods is flow weighed average T-N 22mg/L, T-P 2.4mg/L, the combined Chenseokgyo outfall without the separation wall is average T-N 21mg/L, T-P 2.6mg/L, and the separated Pyoungsong center outfall is average T-N 12mg/L, T-P 1.0mg/L. The T-N, T-P concentration in separated outfall make form about 44%, 42% of the combined outfall, and this means the separated outfall (i.e. storm sewer) is polluted by inflow of sewage. The overflow load of the separated outfall is ten times higher than the combined outfall and its overflow load per rainfall is three times than combined outfall during the wet periods. Therefore, the control plan of overflow load is required in storm sewer. The control effects of the overflow load increased 100% by setting the separation wall in the combined sewer, and showed 44% increase without the separation wall in separated sewer, but forecasted over than 82% increase of effects with the separation wall.
        5,400원
        79.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Payment and security requirement are playing an increasingly critical role in RFID system, allegedly the core of the ubiquitous, especially in logistics. Therefore, security technology has been playing essential role gradually unlike the past when only the perception of equipment was considered important technology. The current encoding system allows the access only to the user who has the secret key. Many encoding algorithm has been studied to ensure the security of secret key. Security protocol is the most typical way to authorize appropriate user perception by using the data and secret key to proceed the encoding and transmit it to the system in order to confirm the user. However, RFID system which transmits more than dozens of data per second cannot be used if the algorithm and protocol of the existing wired system are used because the performance will degrade as a consequence. Security protocol needs to be designed in consideration of property of RFID and hardware. In this paper, a protocol was designed using SNEP(Sensor Network Encryption Protocol), the security protocol used for the sensor similar to RFID- not the current system used in wired environment- and ECC (Elliptic Curve Cryptography: oval curve encoding), the encoding algorithm.
        4,000원
        80.
        2006.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study had carried out to investigate the usage status of customer, the positive effects and problems, and the most important items of the nutrition labeling at purchasing the food etc. on the current nutrition labeling system in order to establish the customer-centric nutrition labeling system. Survey was carried out by questionnaire method that is targeted on adult female above 20 years old in Seoul and Kyeongnam area from May to June, 2004. For the experience of checking the nutrition label of the processed domestic and imported processed food, 82% and 75.4% of the respondents were replied 'have checked' respectively. For the positive effects due to enforcement of the nutrition labeling system, the respondents agreed highly with 'easy to compare with other products' and 'improve the products quality'. For the problems of the nutrition labeling system, the respondents agreed highly with 'different criteria for each product' and 'incendiary purchasing due to false or exaggerated labeling', and gave the higher scale for the positive effects than the problems relatively. For the necessity of the nutrition labeling system, 96.2% of the respondents were replied 'necessary', and it was indicated a significant difference on age and marital status(p<.01). For the price rising due to enforcement of the nutrition labeling system, 55.2% of respondents agreed, and it was indicated a very significant difference on age and monthly income(p<.001). For the most important nutrition labeling items at purchasing the food, the respondents were replied 'total calorie' on most of the food, and in addition, they checked carefully the lipid, cholesterol, protein, Ca, and Fe.
        4,000원
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