• Industry Promotion Research
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• v.9 no.2
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• pp.45-58
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• 2024

This study modelled the social network structure characteristics between Innopolis Start-ups located in Daejeon and Innopolis Start-ups' customers scattered across the country as a tendency of regional clustering among homogeneous technologies, and the observed values were included within the 95% confidence interval of the ERGM(Exponential Random Graph Model) analysis model. If both the research institute and the customer company are located in Yuseong-gu, Daejeon, the probability of being connected is about 13 times higher than if they are located in other administrative districts, and there is a strong tendency of connection between firms with the same technology with a negative value of assortment and homogeneity (0.1904), especially among the six technology sectors, with a P value of 0.035. There was a negative value (-0.0035) among firms not located in Yuseong-gu, with less clustering tendency. This confirms that Yuseong-gu, Daejeon, where the Daedeok Innopolis is located, is forming the centre of an innovation cluster.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.175-181
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• 2017

The purpose of this study is evaluating the characteristics of tensile strength of UHPC and examining tensile performance of notched specimens by direct tensile test. For test variables, 120, 150, and 180MPa of target design standard strength were aimed at. With general water curing and $90^{\circ}C$ high temperature steam as curing conditions, the properties were reviewed. Overall, it was represented that the specimens of notch-type direct tensile strength concrete was effective in inducing central cracks compared with existing direct tension specimens. Through this, it was judged that data construction with high reliability was possible. Above all, in a graph of direct tensile strength and strain, in the case of steam curing at high temperature, there was great difference of initial tensile strength compared with water curing. As passing of ages, an aspect that the difference gradually decreased was shown. Maximum tensile strength was found to increase steadily with increasing age for all target design strengths in water curing, in the case of steam curing, the tendency to increase significantly due to the initial strength development effect at 7 days of age. The initial crack strength increases with age in case of underwater curing, in the case of steam curing, it was higher than that of water curing in 7 days, while the strength of 28 days was lowered. In this part, it is considered necessary to examine the arrangement condition of the steel fiber.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.44-50
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• 2006

To characterize thermo-chemical feature of su gar conversion of woody biomass poplar wood (Populus alba${\times}$glandulosa ) by sub- and supercritical water was treated for 60s under subcritical (23 MPa, 325 and $350^{\circ}C$) and supercritical (23 MPa, 380, 400, and $425^{\circ}C$) conditions, respectively. Among degradation products undegraded poplar wood solids existed in aqueous products. As the treatment temperature increased, the degradation of poplar wood was enhanced and reached up to 83.1% at $425^{\circ}C$. The monomeric sugars derived from fibers of poplar wood by sub- and supercritical treatment were analyzed by high performance anionic exchange chromatography (HPAEC). Under the subcritical temperature ranges, xylan, main hemicellulose component in poplar wood, was preferentially degraded to xylose, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical condition. The highest yield of monomeric sugars amounts to ca. 7.3% based on air dried wood weight (MC 10%) at $425^{\circ}C$.

• Food Science and Preservation
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• v.18 no.1
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• pp.33-38
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• 2011

We investigated the quality characteristics of cookies prepared after addition of various concentrations of used coffee grounds (0%, 1%, 3%, and 5%, all w/w) as a substitute for flour. As coffee grounds concentration rose, decrease in the pH of cookie dough was evident. In terms the water-holding capacity of dough, cookies prepared 3% (w/w) coffee grounds yielded the highest value. With an increase in coffee grounds concentration, the color a value rose, but the L and b values fell. The gelatinization temperature became higher, but both peak viscosity and 15 min-height values declined. The spread and loss ratios decreased but the leavening rate rose significantly with elevation of coffee grounds concentration. The hardness of cookies rose but slightly, as coffee grounds concentration rose. Upon sensory evaluation of all of appearance, flavor, and overall preference, cookies prepared with addition of used coffee grounds were superior to those without grounds, whereas those prepared using 1%-3%(w/w) coffee grounds showed the highest overall acceptability. Thus cookies made using coffee grounds can be economically competitive. In addition, the ingredients of coffee powder and used coffee grounds were shown to be very similar, except that coffee grounds contain 15-fold less caffeine than dose coffee powder. As health concerns are popular today, the use of coffee grounds to manufacture processed food may be acceptable.

• Culinary science and hospitality research
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• v.22 no.7
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• pp.173-186
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• 2016

This study was conducted to investigate quality characteristics of white pan bread with Cudrania tricuspidata leaf powder having functional components. Mixograph, pH, TPA, volume, specific volume, moisture, CrumbScan, color value, sensory evaluation and shelf-life test were performed on the white pan bread with Cudrania tricuspidata leaf powder. The obtained results are as follows. Mixogram analysis results showed that the dough with Cudrania tricuspidata leaf powder was suitable for baking quality. The more Cudrania tricuspidata leaf powder was added in the dough, the higher dough pH was and the lower pH values after fermentation and of the final productwere. TPA analysis results showed that higher amounts of Cudrania tricuspidata leaf powder resulted in increased hardness, chewiness, and gumminess of the white pan bread. Volume and specific volume of white pan bread were decreased with increased amounts of Cudrania tricuspidata leaf powder. CrumbScan images showed that fineness of grain, crust thickness, and volume of the bread were significantly different depending on the amount of Cudrania tricuspidata leaf powder. While color value analysis showed that increasing the amount of Cudrania tricuspidata leaf powder resulted in low L and a values. The results of the acceptance test showed that CLP3 had better scores in the appearance and texture characteristics than the control, while taste and overall acceptance were higher in the CLP2 compared with the control. According to the results of the shelf-life test, the white pan bread with 1~2% of Cudrania tricuspidata leaf powder had a significantly lower hardness when compared with the control. It was judged that a lower amount of Cudrania tricuspidata leaf powder could help in maintaining the softness of bread crumbs. Moisture content in the white pan bread decreased with the increased amounts of Cudrania tricuspidata leaf powder, but there were no significant differences among specimens.

• Journal of Environmental Policy
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• v.11 no.3
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• pp.49-65
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• 2012

Road traffic noise is closely related to road traffic environment, including traffic volumes by type and travel speed. In this study, we stated some issues and analyzed the relationships between road traffic noise and traffic flow characteristics. First, in attempt to find the answer to the question "When does the loudest traffic noise occur?" we reviewed the issue in the terms of traffic flow. As a result of analyzing level of service through Korea Highway Traffic Noise model, the actual maximum noise occurred in level of service D rather than level of service E, on the capacity state. It shows that maximum noise would be most likely to occur right before and after the peak hours. Second, this paper was looking for the method of a more easy and accurate traffic speed estimation to predict traffic noise. This paper proposed sketch planning techniques of speed-volume curve by level of service on Korea Highway Capacity Manual. As a result of trend line modeling, it was judged that quadratic form is a suitable function, and coefficient of determination ($R^2$) was higher than 0.96, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.244-245
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• 2010

최근 광전자 분야에서는 미래 에너지 자원에 대한 관심과 함께 GaN 기반 발광다이오드 및 태양전지 연구가 활발히 진행되고 있다. GaN는 높은 전자 이동도와 높은 포화 속도 등의 광전자 소자에 유리한 특성을 가지고 있으나, 고 인듐 함유량과 막질의 우수한 특성을 동시에 구현하는 것은 매우 어렵다. 이를 극복하기 위한 방법으로써 선택 영역 박막 성장법(Selective Area Growth)은 마스크 패터닝을 통해 제한된 영역에서만 박막을 성장하는 방법으로써 GaN의 막질을 향상 시킬 수 있는 방법으로 주목받고 있다. 본 논문에서는 대면적 기판에서 GaN의 막질 향상뿐만 아니라 고인듐 InGaN 박막 성장을 위하여 서브마이크로미터 주기와 크기를 갖는 홀 패턴을 포토리소그라피 공정 최적화를 통해 구현할 수 있는 방법에 대해 논의한다. 그림. 1은 사파이어 기판 위에 선택 영역 박막 성장법을 이용하여 성장한 n-GaN/활성층/p-GaN의 구조를 나타낸 그림이다. 이를 통하여 서브마이크로미터 스케일의 반극성 InGaN면 위에 높은 인듐 함유량을 가지면서도 우수한 특성을 갖는 박막을 얻을 수 있다. 본 실험을 위하여 사파이어 기판 위에 SiO2를 증착한 후 포토레지스트(AZ5206)을 도포하고 포토리소그라피 공정을 진행하여 2um 크기 및 간격을 갖는 패턴을 형성했다. 그림. 2는 AZ5206에 UV를 조사(5초)하고 현상(23초)한 패턴을 윗면(그림. 2(a))과 $45^{\circ}$ 기울인 면(그림. 2(b)) 에서 본 SEM(Scanning Electron Microscope) 사진이다. 이를 통해 약 2.2um의 홀 패턴이 선명하게 형성 됨을 볼 수 있다. 그 후 수백나노 직경의 홀을 만들기 위해서 리플로우 공정을 수행한다. 그림. 3은 리플로우 온도에 따른 패턴의 홀 모양을 AFM(Atomic Force Microscope)을 이용하여 측정한 표면의 사진이다. 이를 통해 2차원 평면에서 리플로우 온도 및 시간에 따른 변화를 볼 수 있다. 그림.3의 (a)는 리플로우 공정을 진행하기 전 패턴이고, (b)는 $150^{\circ}C$에서 2분, (c)는 $160^{\circ}C$에서 2분 (d)는 $170^{\circ}C$에서 2분 동안 리플로우 공정을 진행한 패턴이다. $150^{\circ}C$와 $160^{\circ}C$에서는 직경에 큰 변화가 없었고, $160^{\circ}C$에서는 시료별 현상 시간 오차에 따라 홀의 크기가 커지는 경향이 나타났다. 그러나 $170^{\circ}C$에서 2분간 리플로우 한 시료 (그림. 3(d))의 경우는 홀의 직경이 ~970nm 정도로 줄어든 것을 볼 수 있다. 홀의 크기를 보다 명확히 표현하기 위해 그림.3에 대응시켜 단면을 스캔한 그래프가 그림.4에 나타나 있다. 그림.4의 (a) 및 (b)의 경우 포토레지스트의 높이 및 간격이 일정하므로, 리플로우에 의한 영향은 거의 없었다. 그림. 4(c)의 경우 포토레지스트의 높이가 그림.4(a)에 비해 ~25nm 정도 낮은 것으로 볼 때, 과도 현상 및 약간의 리플로우가 나타났을 가능성이 크다. 그림. 4(d)에서는 ~970nm의 홀 크기가 나타나서 본 연구에서 목표로 하는 나노 홀 크기에 가장 가까워짐을 확인할 수 있었다. 따라서, $170^{\circ}C$ 이상의 온도와 2분 이상의 리플로우 시간 조건에서 선택 영역 성장을 위한 나노 홀 마스크의 크기를 제어할 수 있음을 확인하였다.

• Korean journal of food and cookery science
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• v.7 no.4
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• pp.15-22
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• 1991

Changes in cooking properties of kidney beans A (reddish purple), B (mosaic), and C (pale yellow) during storage at $4^{\circ}$, $20^{\circ}$ and $30^{\circ}C$ for 5 months were examined. The weight and volume gains of raw beans during soaking at $30^{\circ}C$ were the greatest in kidney bean A followed by B and C, which were decreased from 3 months storage at $30^{\circ}C$. The weight gain, solid loss and hardness of cooked beans at $100^{\circ}C$ for 40 min decreased from 3 months of storage at $30^{\circ}C$ in all samples. The amylograms of whole kidney bean flours showed no peak and continuous increase of viscosity during heating. The kidney bean A showed the higher values in all reference points than kidney beans B and C which had similar amylogram patterns.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.580-586
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• 1996

Gelatinization behavior and morphology of epichlorohydrin-crosslinked potato starches (XPs) were investigated. Native potato starch showed a very steep single stage swlling pattern, but crosslinked starches showed various patterns with the degree of crosslinking. Swelling power, solubility and light transmittance were reduced drastically as the degree of crosslinking increased. Brabender initial pasting temperature and peak temperature of crosslinked starches increased because the crosslinking reinforces the intermolecular net work of the starches. Although the swelling of the potato starch granule was inhibited by crosslinking as compared to that of the native one, Brabender peak viscosities (6.5% w/v, db) were on the order of 2,500 units for the native potato starch, 3,700 for the XP with 2.300 anhydroglucose units per crosslinking (AGU/CL) and 3,400 for the XP with 2,100 AGU/CL, due to the decreased breakdown of the swollen granule resulting from the resistance to heat and shear. The XP with 1,900 AGU/CL, however, did not show the peak viscosity and the viscosity was on the order of 500 units because of the excessive unhibition of the swelling. Unlike the native potato starch, 6.5%(m/v, db) pastes of the crosslinked potato starches could form gels, which could be predicted from the Brabender setback and consistency index. When the degree of crosslinking is low, random contraction and radial swelling of the granule was possible. As the degree of crosslinking increased, morphological change became similar to the single dimensional tangential swelling observed from the lenticular wheat starch. These morphological change during heating in excess water explained the gelatinization behaviors of crosslinked starches tested.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.538-542
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• 2015

The transverse moment of inertia is an indispensable factor in analyzing the roll motion characteristics of ships and the calculating method needs to be based on the more reasonable theories when deciding the value as the results and reliability of analysis could be much affected by the correctness. However, the mass distribution and shape of hulls are quite complicated and give much difficulties in case of calculating the value directly from the ship design data, furthermore even acquiring the detailed design data for calculation is almost impossible. Therefore some simpler ways are practically adopted in the assumption that the gyradius of roll moment can be decided by a given ratio and hull width. It is well known that the responses of the free roll decay are varied according to the value of roll moment in view of roll period and amplitude decay ratio, so that the general formula to get the moment value can be derived also from the observation of roll decay responses. This study presents how the roll period and decay ratio are interrelated each other from the roll motion characteristics with suggesting a general formula to be able to calculate roll moment from it. Finally, the obtained general formula has been applied to a ship data to check the resultant characteristics through analyzing graphs and showed that the roll moment becomes more accurate when rolling period and decay ratio are considered together in calculation.