• 한국식품과학회지
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• 제38권1호
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• pp.35-41
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• 2006

Fresh-cut 사과의 미생물학적 품질 보존성 향상을 위해 미생물 생육억제 효과가 크다고 알려진 다양한 hurdle 인자를 개별 평가하고 이들의 병용처리 효과를 검토하여 적용 가능성을 확인하고자 하였다. Chitooligosaccharide와 GSE(grapefruit seed extrat)를 처리한 fresh-cut 사과는 저장 후반으로 혹은 농도가 높을수록 무처리구에 비해 총균수가 증가하는 현상이 나타나 미생물 증식억제를 위한 hurdle로써의 적용이 어렵다고 판단되었다. Citric acid의 경우 malic acid와 유사한 결과를 보였으나 0.75% 이상의 citric acid 처리구에서는 malic acid 처리구와 달리 $18^{\circ}C$ 저장 4일을 전후해 총균수가 증가하는 현상을 보였다. 이에 미생물 증식억제의 주요 hurdle로 malic acid를 선정하였고, 부가적인 hurdle로는 미생물 생육억제 효과를 나타내면서 갈변 및 조직연화를 지연시켜 주는 ascorbic acid와 calcium chloride로 선정하였다. 이들의 최적 dipping solution의 구성 및 함량은 미생물 저해 및 갈변 방지측면을 모두 고려하여 최소 0.25% malic acid: 0.5% ascorbic acid: 0.25% calcium chloride, 최대 0.75% malic acid: 1.0% ascorbic acid: 0.75% calcium chloride로 결정하였다.

• 가족자원경영과 정책
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• 제8권1호
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• pp.79-100
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• 2004

This study attempted to examine the employment instability on consumer's use of credit as a financing medium. The purpose of this study was 1) to examine the effect of employment related factors on consumers' use of credit; 2) to compare the results between the two different economic situations. A conceptual framework was developed based on the permanent income hypothesis, family stress theory, and the previous empirical studies. Using data on working households ih the 1992 and 1998 Survey of Consumer Finances (SCF), double-hurdle analyses were conducted. The results suggested that employment related factors that measured employment stability were significantly related to the likelihood of having an outstanding balance on their credit account but were not the influential factors in determining the amount of the outstanding balance. Among other factors, resources factor played the most significant role in determining both the likelihood of having an outstanding balance and the amount of the balance. Although the 1992 and 1998 data represent economic downturn and economic prosperous period, the effects of the factors including employment instability factors were similar between the two periods. This imply that employment instability has increased even in the economic prosperous period. From the findings, several implications for policy makers, credit industry, and financial educators were suggested.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.149-155
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• 2001

Recently, it is required to design higher stage pressure ratio compressor while maintaining equal adiabatic efficiency. To increase the stage pressure ratio, blade rotational speed or diffusion factor should be increased. In the case of increasing rotational speed, relative speed of flow at blade leading edge is well supersonic. In supersonic blade, total pressure loss is mainly due to shock wave and blade leading edge thickness should be very thin to minimize the shock wave loss. As a result, the blade is like to be week in terms of mechanical strength and the manufacturing cost is very high because NC machining is necessary. It is also one of big hurdle to overcome to make small compressor. In this paper, the effects of blade leading edge to the performance of supersonic blade In terms of total pressure loss. The efficiency of already known method to make thin blade leading edge from the casted blade with rather thick leading edge thickness is also assessed.

• 가족자원경영과 정책
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• 제6권1호
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• pp.73-85
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• 2002

This study examined which factors influence the parental borrowing for children's college education in the U.S. A double-hurdle model was applied to analyze both the parents’decision to borrow and the amount of borrowing. Parents’income and total costs of college attendance had significant positive effects on both the decision to borrow and the amount borrowed. Students’income, parents’cash and savings had significant negative impacts on the amount borrowed, while home equity and the students’expected future income were significant positive factors. Greater amounts of grants significantly increased the probability of borrowing, but reduced the loan amount. Parents with smaller household size, and those who were college graduates were more likely to borrow. White parents borrowed greater amounts than did their non-White counterparts. The age of the student was a significant negative factor in the probability, as well as the level, of borrowing.

• Current Photovoltaic Research
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• 제11권3호
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• pp.87-95
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• 2023

As the demand for the Internet of Things grows, research into indoor photovoltaics for wireless power is becoming important. In particular, perovskite has attracted considerable attention due to its superior performance compared to other candidates. However, various surface defects present in perovskite are a limiting factor for high performance. In particular, deep-level surface defects caused by uncoordinated Pb²⁺ ions directly limit charge transport. In low light environments, this appears to be a more significant hurdle. In this study, ethylenediamine, which can provide covalent bonding to uncoordinated Pb²⁺ ions through nitrogen, was used as a surface treatment material for indoor photovoltaics. X-ray photoelectron spectroscopy confirmed that the uncoordinated Pb²⁺ ions were effectively passivated by the terminal nitrogen of ethylenediamine. As a consequence, a V_OC of 0.998 V, a JSC of 0.139 mA cm^-2 and a fill factor of 83.03% were achieved, resulting in an indoor photoelectric conversion efficiency of 38.02%.

• Journal of Microbiology and Biotechnology
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• 제23권8호
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• pp.1176-1184
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• 2013

Anti-hepatocyte growth factor (anti-HGF) monoclonal antibodies (mAbs) are potential therapeutics against various cancers. Screening for high-producer clones is a time-consuming and complex process and is a major hurdle in the development of therapeutic mAbs. Here, we describe an efficient approach that allows the selection of high-producer Chinese hamster ovary (CHO) cell lines producing the novel anti-HGF mAb SFN68, which was generated previously by immunizing HGF bound to its receptor c-Met. We selected an SFN68-producing parental cell line via transfection of the dihydrofolate reductase-deficient CHO cell line DG44, which was preadapted to serum-free suspension culture, with an SFN68-expression vector. Subsequent gene amplification via multiple passages of the parental cell line in a methotrexate-containing medium over 4 weeks, followed by clonal isolation, enabled us to isolate two cell lines, 2F7 and 2H4, with 3-fold higher specific productivity. We also screened 72 different media formulated with diverse feed and basal media to develop a suboptimized medium. In the established suboptimized medium, the highest anti-HGF mAb yields of the 2F7 and 2H4 clones were 842 and 861 mg/l, respectively, which were about 10.5-fold higher than that of the parental cell line in a non-optimized basal medium. The selected CHO cell lines secreting high titers of SFN68 would be useful for the production of sufficient amounts of antibodies for efficacy evaluation in preclinical and early clinical studies.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1279-1284
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• 2014

The binding of TATA-binding protein (TBP) to the TATA-box containing promoter region is aided by many other transcriptional factors including TFIIA and TFIIB. The mechanistic insight into the assembly of RNA polymerase II preinitation complex (PIC) has been gained by either directly altering a function of target protein or perturbing molecular interactions using drugs, RNAi, or aptamers. Aptamers have been found particularly useful for studying a role of a subset of PIC on transcription for their ability to inhibit specific molecular interactions. One major hurdle to the wide use of aptamers as specific inhibitors arises from the difficulty with traditional assays to validate and determine specificity, affinity, and binding epitopes for aptamers against targets. Here, using a technique called the bio-layer interferometry (BLI) designed for a label-free, real-time, and multiplexed detection of molecular interactions, we studied the assembly of a subset of PIC, TBP binding to TATA DNA, and two distinct classes of aptamers against TPB in regard to their ability to inhibit TBP binding to TFIIA or TATA DNA. Using BLI, we measured not only equilibrium binding constants ($K_D$), which were overall in close agreement with those obtained by electrophoretic mobility shift assay, but also kinetic constants of binding ($k_{on}$ and $k_{off}$), differentiating aptamers of comparable KDs by their difference in binding kinetics. The assay developed in this study can readily be adopted for high throughput validation of candidate aptamers for specificity, affinity, and epitopes, providing both equilibrium and kinetic information for aptamer interaction with targets.

• 대한환경공학회지
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• 제22권2호
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• pp.323-329
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• 2000

막결합형 활성슬러지 공정은 막오염으로 인한 플럭스 감소 때문에 시스템의 경제성과 효율성이 떨어지는 문제점을 지니고 있어 막오염에 대한 체계적인 연구가 요구되고 있다. 따라서 본 연구에서는 한외여과막과 결합된 활성슬러지 시스템을 운영하면서 막오염 유발 인자를 규명하고자 하였다. 활성슬러지 공정의 운전 초기에 급격한 플록 크기 감소와 동시에 급격한 플럭스 감소가 관찰되었다. 초기 플럭스 감소현상은 활성슬러지 플록의 입자 크기 감소로 인한 케이크 저항의 증가가 주요 원인이었다. 이것은 운전시간에 따른 각 여과 저항값을 측정하여 확인하였다. 또한, 플록 해체로 인하여 EPS 양이 운전 전보다 약 150 % 가량 증가한 것을 볼 때 EPS 양의 증가가 케이크 저항 증가의 또 다른 원인이 될 수 있음을 제시하였다.

• 무역상무연구
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• 제40권
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• pp.3-30
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• 2008

This article attempts to describe and analyze the rules on the buyer's remedies for lack of conformity under PELS. It shows that such remedies under the PELS operate in a two-tier remedial scheme which is alien to both domestic and international legal systems. That is, repair and replacement take the position of primary remedy, whereas termination, price reduction and damages are secondary remedies which are available only where the primary remedies cannot be invoked. Notwithstanding its superiority, the PELS have some drawbacks in several aspects. First, the PELS seems to place its focus on the factor of cost except the other factors, for instance, the significance of the lack of conformity, when one decides whether the first tier remedies cause the seller unreasonable effort or expense. It is argued that the factors can be considered by referring to art. 1:302 PECL. Second, the PELS does not expressively provide any exclusion of the seller's right to choose between repair or replacement on the basis of unreasonable uncertainty in reimbursing the expenses advanced by the buyer. It argues that if there is such uncertainty, it should be regarded as causing the buyer an unreasonable inconvenience under art. 4:204(1). Third, the PELS does not seem to properly reflect the consumer's interests in that most consumers prefer to have the absolute right of termination as against the commercial sellers who have a relatively stronger bargaining position. The reasons for that is that there is a big hurdle, i.e., a hierarchy of remedies, to be overcome by the consumer to battle with the commercial seller, and that unavoidable vagueness in defining a minor lack of conformity has been often used against the consumer, but in favour of the commercial seller with a strong bargaining position.

• 교육시설 논문지
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• 제21권3호
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• pp.3-10
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• 2014

A study of facility securement and space utilization at national universities in Korea was conducted in order to help develop an efficient model for space management at national universities going forward. For the study, 36 national universities were asked to submit answers to a questionnaire on usage of campus facilities in 2013. We then analyzed the results of space management for the 27 universities that participated in the questionnaire in each of the past three years (2011-2013). Lastly, we conducted an awareness test on the space utilization policies and space management for these universities. The results are as follows. First, the aggregate average score for space utilization over the past three years is 74.06. The annual average score increased year-over-year and then decreased; it was 69.44 in 2011, 80.68 in 2012, and 72.05 in 2013. A decline in the sense of responsibility of universities to effectively manage space appears to be a factor in the decrease. Second, with 53% of respondents in agreement, treatment of campus area as private space appears to be the biggest hurdle for efficient space management. As such, a plan to foster a more communal view of campus facility area is required. Third, resistance from constituents to existing guidelines for space allocation on campuses appears to be limited (78.1% of respondents answered the guidelines currently in place were average, satisfactory, or very satisfactory). We believe this result points to a mutual understanding forming amongst constituents regarding guidelines on space allocation on campus.results of satisfaction research: the users are generally satisfied with education and student.