• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.47-54
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• 1996

UASB reactor was operated for treating wastewater containing high sulfate to assess their performance, competition between sulfate-reducing bacteria(SRB) and methane-producing bacteria(MPB), and the change in the characteristics of microbial granules according to change of hydraulic retention time(HRT) in the reactor. The reactor was fed with a synthetic moderate strength wastes(glucose, 2000 mgCOD/l) containing high sulfate($2400mgSO_4{^{2-}}/l$). The organic loading rate(OLR) ranged from 1.5 to 3.0 gCOD/l.d as HRT maintained 15 to 30 hrs in the stage I. The COD removal efficiency was between 80 to 92%. During this period, methane yield rapidly decreased from 0.3 to 0.1 1 $CH_4$/gCODremoved. While sulfide concentration in the effluent increased from 80 to 200 mgS/l. This indicates that SRB becomes dominant over MPB at a relatively long HRT in the excess sulfate. When OLR of reactor maintained from 5 to 8 gCOD/l.d in the stage II, methane yield increased from 0.1 to 0.17 1 $CH_4$/gCODremoved regardless of decrease of COD removal efficiency. This indicates that SRB is more sensitive to the change of a short HRT than MPB. In the competition between SRB and MPB, about 30% of the removed COD was utilized by SRB at HRT of 30 hrs during the start-up period, while about 73% was used by SRB at HRT of 15hrs at the final step of second experimental stage. Whereas after shock exposure of OLR about 62% was utilized by SRB at HRT of 5hrs. It indicates that SRB is strongly suppressed by the wash-out of significant dispersed SRB since a large electron flow is distributed to the MPB. In addition, the granulation in the presence of high sulfate is unfavoured at a long HRT because of substrate transport limitations into MPB like Methanothrix spp. which is an important factor in the composition of the granules. Accordingly, granule sizes in the UASB reactor decreased with time due to weak network frame of granules by the decreased activity of MPB.

• Land and Housing Review
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• v.4 no.3
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• pp.287-294
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• 2013

Energy saving strategy for public housing is given a sizable portion in Land and Housing corporation. From this reason, the consumer's characteristics and energy consciousness of public housing dweller was derived from field survey for compare with sale housing residents characteristics. Utilities fees (e.g. gas and electric) for public housing residents was about 50 percent of sales housing dweller, but real energy consumption was accounting for 70% of sales housing residents in electric consumption. Among the respondents for public housing dweller up to 80 percentile of end-user comment that they have less demanding utilities fees. Given the major energy saving strategies, such as install EMS, make a teaching tool for children, sale housing residents is more proactive approach to participant energy saving strategies than public housing residents.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.227-227
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• 2010

동력 전달을 위한 구동 부품에 대한 내마모성 개선을 통한 에너지 효율 및 부품의 수명 향상에 대한 사회적 관심이 급증하고 있다. 특히, 최근에는 자동차용 구동부품에 저마찰 내마모 특성이 우수한 Mo-N-Cu 나노복합체 박막에 대한 연구가 활발하게 진행되고 있다. 본 연구에서는 Mo-N-Cu 나노복합체 박막을 마그네트론 스퍼터링 증착법을 활용하였고, 이때 Mo 및 Cu 타겟을 적용하여 동시에 증착하였다. 진공 챔버의 진공도는 $5{\times}10^{-6}\;Torr$ 이하의 초기 진공도를 확보한 이후, 알곤 및 질소 가스를 주입하여 공정 압력이 5 mTorr 수준이 되도록 하였다. 이때 N2/(Ar+N2) = 0.5를 유지하였다. Mo-N-Cu 박막내에 Cu 함량 변화를 위해 Mo 캐소드는 D.C. 1 kW로 고정하고 Cu 캐소드에 R.F. 파워를 0, 40, 60, 80 W로 변화하였다. 박막의 두께는 증착시간을 변화하면서 $1\;{\mu}m$ 이상이 되도록 하였다. Cu 캐소드에 인가된 파워의 변화에 따라 Mo-N-Cu 박막내 Cu 함유량은 10 at.%까지 변화되는 것을 EDX 분석을 통해 확인하였다. 또한 증착된 Mo-N-Cu 박막의 표면 및 단면에 대한 FE-SEM 분석을 통하여 전형적인 주상구조를 지닌 MoN 박막에서 Cu 함량이 증가할수록 Mo-N-Cu 박막의 결정성을 방해하는 것을 확인하였다. 또한 XRD 분석을 통하여 박막의 결정 구조 분석을 하였고, Nano Indentor를 통하여 30 GPa 수준의 고경도를 지닌 박막이 형성됨을 확인하였다. 박막의 내마모 특성 평가를 위해 ball-on-disk 트라이보미터를 활용하여 마찰계수 평가를 수행하였고, Cu 함유량의 변화에 따라 마찰계수가 MoN 박막의 경우 0.8에서 Cu 함량이 5 at.%에서 0.15로 급격하게 낮아짐을 확인하였다.

• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.97-101
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• 2001

The transport and allocation of photosynthetic assimilate is an important regulatory factor in plant productivity, In order to modify assimilate partitioning in rice, transgenic plants containing a potato sucrose transporter (SuT) gene were developed. Calli derived from rice seeds (Oryza sativa L. cv Dongjin) were cocultured with A. tumefaciens LBA 4404 harboring the SuT gene. Calli were transferred to MS medium supplemented with 50 mg/L hygromycin, 500 mg/L carbenicillin, 2 mg/L kinetin, 0.1 mg/L NAA. After 2 weeks, hygromycin resistant shoots were obtained from the calli on the selection medium. Roots were induced from the putative transgenic shoots on rooting MS medium supplemented with 250 mg/L cabenicillin. Plant regeneration rate from the calli was about 150%. Stable incorporation of the potato SuT gene into rice genomic DNA was confirmed by PCR and Southern blot analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.55-60
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• 2013

Compound bows use levering systems consisting of cables and cam pulleys to bend limbs that are much stiffer than those of recurve bows, thus storing more energy while requiring less force for the archer to hold the bow at a fully drawn position. Many patents have thus far been proposed to improve the efficiency and performance of compound bows through empirical methods, whereas only a few analytical methods have been proposed. In this light, this paper presents a method for the kinematic analysis of levering systems in compound bows so that a designer can easily predict the effects of changes in the cam profiles and limb materials.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.790-793
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• 2005

Recently, the interest in the extension of human life and personal health has been increased. Accordingly, many researchers in a pharmacy and a medical world have been making efforts to improve the sustained drug release property and the stability of drug release property in a body. Many biological researches have demonstrated that chitosan derivatives are effective, safe absorption enhancers that can improve the delivery efficiency of drug and vaccine, and they are suitable for controlled drug release because they have good stability, bio-compatibility, and biodegradability. In this study the experiment was performed in vivo by utilizing chitosan nanoparticles as a biopolymer to control drug delivery rate at an optimal temperature, pH, and concentration. It was observed that nanoparticles containing insulin could effectively control the blood glucose at a low level.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.65-73
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• 2009

IEEE802.11 Wireless LAN(WLAN) is being widely used in public space such as airport, and increases the networking boundary in campus and enterprise, and it has lastly attracted considerable attention for mesh network and converged network with other 3G mobile communication networks. In WLAN, load balancing among Access Points(AP) is an important issue for efficient resource management or supporting the Quality of Service(QoS) of traffic, but most researches focused on the AP selection in network entry or roaming of Stations(STA). In this paper, we propose an AP-Initiated Flow Redirection(FR) for AP load balancing by monitoring AP's availability in the true sense. When the AP's resource becomes almost saturated, that is used more than a specific threshold, the AP queries the roaming possible neighbor APs about their availability and calculates the distribution of traffic load with statistical methods such as entropy or chi-square. Finally, the AP decides flows and new APs for redirection and performs it. Our simulation results show that our FR mechanism increases the performance in the various views.

• Horticultural Science & Technology
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• v.16 no.2
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• pp.229-232
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• 1998

This study was conducted to determine the properties of seedling plate papers currently used in commercial production, then to get basic information for manufacturing new seedling plate paper. Imported seedling plate paper had high wet tensile and burst strengths in its usage circumstances. Wet tensile strength was very high with 38.7% of dry tensile strength. Wet burst strength was also very high with 62.4% of dry burst strength. The seedling plate paper contained about 30% of synthetic fibers. It had 10 Gurley sec. in air permeability indicating effective movement of air. Seedling plate papers were' made in laboratory scale. For sufficient sizing degree, the addition of 0.5% AKD (alkylketene dimer) by weight was good enough. Additional amount of AKD more than 0.5% by weight caused strength loss even though improving sizing effect. The addition of wet strength reagent such as Finex-B 2% by weight resulted in good strength and air permeability.

• Journal of KIISE
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• v.42 no.7
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• pp.834-839
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• 2015

Recently, wellness has become an issue related to improvements in personal health and quality of life. Data that are accumulated daily, such as meals and momentum records, in addition to body measurement information such as body weight, BMI and blood pressure have been used to analyze the personal health data of an individual. Therefore, it has become possible to prevent potential disease and to analyze dietary or exercise patterns. In terms of food and nutrition, analyses are performed to evaluate the health status of an individual using dietary data. However, it is very difficult to process the large amount of dietary data. An analysis of dietary data includes four steps, and each step contains a series of iterative tasks that are executed over a long time. This paper proposes a problem solving environment that automates dietary data analysis, and the proposed framework increases the speed with which an experiment can be conducted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2253-2260
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• 2009

The typical distribution systems have the power flow from distribution substations (sources) to customers (load) only as one direction. However, in the case where new energy power sources are connected to distribution systems, the output variations of new energy sources to distribution systems, which is so called reverse power flow, may cause the bi-directional power flow. So, the reverse power flow has severe impacts on typical power system, for example power quality problems, protection coordination problems, and so on. Therefore, this paper proposes the algorithm for Multi-functional protection devices in distribution systems in the case where new energy sources are interconnected. The proposed algorithm is verified to show the effectiveness by simulating and experimenting the prototype systems.