• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1221-1226
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• 2000

Influence of characters of fly ash on the fluidity of cement paste with polycarboxylic acid type superplasticizer has been investigated in connection with the particle size of distribution, unburned carbon content, specific surface area and shape of fly ash. The fluidity of paste is increased with increasing roundness of fly ash and it is decreased with increasing n-value of Rosin-Rammler distribution function. There is a linear correlation between roundness/n-value and fluidity of fly ash cement paste.

• Journal of the Korean Mathematical Society
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• v.53 no.5
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• pp.1133-1148
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• 2016

In this paper, we first discuss a representation of solutions to the initial value problem and the initial-boundary value problem for discrete evolution equations $${\sum\limits^l_{n=0}}c_n{\partial}^n_tu(x,t)-{\rho}(x){\Delta}_{\omega}u(x,t)=H(x,t)$$, defined on networks, i.e. on weighted graphs. Secondly, we show that the weight of each link of networks can be uniquely identified by using their Dirichlet data and Neumann data on the boundary, under a monotonicity condition on their weights.

• Korean Journal of Community Nutrition
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• v.21 no.6
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• pp.574-579
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• 2016

Objectives: Vitamin C has various functions such as antioxidative effect and supporting absorption of iron (Fe). Aim of this present study was to provide vitamin C nutrition information and to briefly evaluate absorption interaction of vitamin C and Fe content of vitamin C emphasized products. Methods: Vitamin C emphasized foods including beverages, cereal, snacks, chocolate products, other cocoa products, and sugary products were examined by HPLC. Fe contents in samples after dry-ashing were examined by ICP. Results: Vitamin C content ranges in various products tested were the following: beverages (n=11) $20.15{\pm}0.08{\sim}845.41{\pm}6.07mg$, cereal (n=11) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$, snacks (n=1) $50.00{\pm}0.25mg$, chocolate products (n=1) $311.73{\pm}2.44mg$, other cocoa products (n=1) $311.73{\pm}2.44mg$, other sugary products (n=2) $52.50{\pm}0.23{\sim}262.50{\pm}0.07mg$. Vitamin C (n=27) analysis values ranged from 82 to 450% of the labeled value. Vitamin C content in vitamin C emphasized food (n=6) was estimated 7.7 times~56.6 times more than Fe content. Conclusions: Analyzed samples ranged more than 80% of the labeled value in vitamin C emphasized products, which complied with food labeling regulation. But, beverages (n=3), cereal (n=4), chocolate products (n=1) were 2 times more than the labeled value. To provide accurate nutrition information, food manufactures should supervise nutrition labeling and understand the interactions between nutrients. Also, consumer should decide about the adequate amount of nutrient intake by thoroughly checking nutrition labeling.

• Journal of the Korean association of regional geographers
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• v.16 no.2
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• pp.100-109
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• 2010

The study examines two different sites to analyze the difference of stream channel profile between two different landuse areas on Neponset River, Boston, MA. Landuse represents the current status of land in terms of human, agricultural or forest, industry and environmental activity types. According to the previous research, forest and urban area are significantly distinguished in chemical characteristic, shape and bed load of the stream. On the chosen sites, I look at the cross-section profile, the slope, velocity, and roughness of the channels. With the data collected at the site I determined the value for the channel bed material using Manning's equation, and compared with the result of HEC-RAS model with the cross-section profile data I measured. In the forest area, water surface elevation and bed material obtained through Manning's equation are very close to HEC-RAS model result. However, in the resident area the Manning's 'n' value calculated much higher than assumption which was considered as cobble whose 'n' value is 0.03-0.06. The difference could be caused by unusual steep elevation on the site and the dam present down further. With the steep elevation upside of dam, there is critical-depth condition occurs. The difference of Manning's 'n' value reflects the difference of depth. HEC-RAS model was run to analyze the difference and the result shows that depth is 0.36 much less than 0.688 what I computed when the Manning's n value is 0.03(cobble) instead of the result of the study (0.13292). Beside, dam is a major source of fragmentation and degradation of stream, and it's possibly inferred upstream water levels are increased and stream velocity is decreased. This study is meaningful for introduction of HEC-RAS in geography field to analyze different sites with channel bed material, and it is going to be used more actively to manage river and river side.

• Korean journal of food and cookery science
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• v.16 no.6
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• pp.511-520
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• 2000

To investigate the effect of sugar and drying method on quality and storage characteristics of beef jerky, storage, textural and sensory characteristics were examined. Water activity was decreased as storage time was prolonged and the honey and rice syrup-added natural dried samples(N-H, N-R) were recorded the lowest value, 0.71 at five weeks of storage. During the storage period, pH values of all the samples were decreased and honey-added and heated air dried beef jerky(H-H) had the lowest pH value, 5.22. L, a, b values had a tendency to decrease, during the storage period. During the storage period, TBA values of all samples showed increasing tendency. Sugarsyrup-added samples(N-S, H-S, S-S$\^$*/) had the lowest TBA value, and those of honey-added samples(N-H, H-H, S-H$\^$**/) were highest, regardless of drying method. Total plate counts of bacteria and the number of lactic acid bacteria were increased as storage time was prolonged. Sugar syrup-added and heated air dried beef jerky(H-S) had the lowest in total plate counts of bacteria and the number of lactic acid bacteria, at five weeks of storage. Textural properties value of all samples were increased as storage time was longer. Honey-added samples showed the higest springness and cohesiveness value and sugarsyrup-added and natural dried sample showed the highest value in chewiness, gummness and hardness. In the almost sensory score of natural dried beef jerky was decreased asstorage time was prolonged, regardless of packaging method. The sensory score of heated air dried samples were higher than those of natural dried samples, regardless of packaging method. $\^$*/S-S sucrose syrup added smoking dried sample, $\^$**/S-H honey added smoking dried sample

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.45-53
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• 2012

Ground drilling is a common method to conduct site investigation, soil improvement, and pile installation. In the point of construction ground drilling requires electrical energy to drill a hole in ground in which the energy exerts into the motor located on the head of auger and generates rotational power. In this paper it is verified that the exerted electrical energy is closely related to the strength characteristics of ground. Measurement sensors, recording system, and drilling system were developed to obtain exerted motor current and drilling depth and laboratory soil box tests were carried out. The measured motor current and boring depth were applied to predict SPT N-value and the prediction results were compared to SPT N-value of laboratory tests. The test results show that the exerted electrical energy to bore ground be a good index to estimate SPT N-value.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.165-170
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• 2009

Purpose: Nowadays, NM (in vitro lab) and LM (TLA lab) are overlaped in almost all tests. in this case, how can NM develop continually in a keen competition with LM. we studied to find out current situation and problems after comparing NM with LM. Then, to improve our technic. Methods and meterials: We studied from October 2008 to February 2009 at department of nuclear medicine Seoul National University Bundang Hospital visited 108 patients. We assayed TSH, $FT_4$ by Ria-mat{TSH (n=23), $FT_4$ (n=19)} and AFP, CEA, PSA by manual. {AFP (n=24), CEA (n=31), PSA (n=31)}. On the other hand, LM was measured by TLA system. Results: NM was similar to LM (value of AFP), NMLM (value of PSA,TSH), NM$\leqq$LM (value of $FT_4$ in range 0.01~1.00 ng/mL), NM$\geqq$LM (value of $FT_4$ in range 1.00~6.00 ng/mL) Conclusions: There was no test which result showed big difference remarkably, but several tests have some difference totally or partly. It means that there is possibility to judge wrongly (normal patient->abnormal, abnormal->normal). So, we need to consider always when we report the result.

• Korean Journal of Metals and Materials
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• v.46 no.4
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• pp.217-222
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• 2008

Characteristics of etching and induced surface morphology variation by wet-etching of n-face n-type GaN were investigated using KOH solutions. It was observed that hexagonal pyramids were formed on the etched surface regardless of etching conditions. However, the size of the hexagonal pyramids was changed as the etching time and temperature increased, respectively. Initially, as the etching time and concentration of KOH solution increased, the hexagonal pyramid was observed to be dissociated into smaller pyramids. However, as the etching time increased further, the size of the hexagonal pyramids increased again, indicating that the etching of N-face n-type GaN by KOH solutions proceeded through the evolution of hexagonal pyramids, such as formation, dissociation and enlargement of pyramids. Furthermore, it was also observed that there is a correlation between the photoluminescence intensity of the etched surface and the value of root-mean-square roughness. The intensity of PL increased as the roughness value increased due to the enhancement of the extraction efficiency of the generated photons.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.129-139
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• 2012

Given digraph network $D=(N,A),n{\in}N,a=c(u,v){\in}A$ with source s and sink t, the maximum flow from s to t is determined by cut (S, T) that splits N to $s{\in}S$ and $t{\in}T$ disjoint sets with minimum cut value. The Ford-Fulkerson (F-F) algorithm with time complexity $O(NA^2)$ has been well known to this problem. The F-F algorithm finds all possible augmenting paths from s to t with residual capacity arcs and determines bottleneck arc that has a minimum residual capacity among the paths. After completion of algorithm, you should be determine the minimum cut by combination of bottleneck arcs. This paper suggests maximum adjacency merging and compute cut value method is called by MA-merging algorithm. We start the initial value to S={s}, T={t}, Then we select the maximum capacity $_{max}c(u,v)$ in the graph and merge to adjacent set S or T. Finally, we compute cut value of S or T. This algorithm runs n-1 times. We experiment Ford-Fulkerson and MA-merging algorithm for various 8 digraph. As a results, MA-merging algorithm can be finds minimum cut during the n-1 running times with time complexity O(N).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.275-283
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• 2016

In this study, three knee-orthoses (dial lock type, medium size, right side) were used for a quality level test (static bending test and solidity test of the locking system) of the knee-orthosis locking system. In the static bending test, a smaller maximum load was observed in samples A and C compared to the reference standard value (KS P 8408 standard value: 1000 N, sample A: 865 N, sample C: 833 N). In addition, in the solidity test of the locking system, a smaller maximum load was observed in the all samples compared to the referenced standard value (KS P 8411 standard value: 200 N, sample A: 41 N, sample B: 97 N, sample C: 54 N). Korean industrial standards for knee-orthoses and systematic test methods are lacking. Therefore, a systematic management plan for knee-orthoses is required. The result of the current study showed that a systematic management plan for the knee-orthosis locking system is required. In particular, the development of a quantitative and objective test method is needed. The findings of the current study may be useful for monitoring the quality of the knee-orthosis locking system and may provide foundational information for the development of a quantitative and objective test method.