• 환경영향평가
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• 제17권1호
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• pp.1-9
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• 2008

Non-point pollution is caused by many diffusive sources, unlike a point pollution derived from industrial wastewater treatment plants or sewage treatment plants. Runoff of non-point pollutants is originated from rainfall or thawing in short period of time moving over and through the a ground surface. They cause ill effect on the quality of neighboring aquatic environment. To prevent effectively the wash off from non-point pollutant, it should be immediately reduced at the source or be treated after gathering of runoff water. This study has been carried out for the best width of riparian buffer zone. So we implemented the experiment in terms of its depth, width and kind of vegetations and calculated the reduction of pollutants loading. The experimental zone encompasses the watershed of Namhan River (Kyunggido Yangpyunggun Byungsanri). The region was divided into 5 land cover sectors : grass, reed, pussy willow, mixed(grass+pussy willow) and natural zone to compare effectiveness of vegetation. Water samples from four points have been collected in different depths. And the pollutant removal efficiency by sectors with different plant species was yielded through influent with one of each sample. And we obtained the correlation between the width of riparian buffer zone and the removal efficiency of pollutants. Using correlation result, the width of riparian buffer zones which needs to improve the water quality of river could be derived.

• 한국물환경학회지
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• 제20권6호
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• pp.555-562
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• 2004

This paper presents the development and application of a riparian buffer zone design model(RBZDM). The model was developed as a decision-making tool for watershed management, by integrating geographic information system(GIS) and analytical hierarchy process(AHP) theory. Several factors for watershed management, such as pollution removal capacity, land aquisition cost, distribution of point and non-point pollution sources, and possibility of new pollution source location, were analyzed based on AHP theory. The vegetated buffer zone width was designed using GIS-based riparian buffer analysis. The developed model was applied to the Kyoungan Stream watershed, which is an important part of Paldang lake catchment area. The Kyoungan stream watershed was divided into sixteen subbasins. Six of them belong to the main stem, where the model was applied. Ten alternatives of buffer zone width and five hierarchial levels were designed. The relative importance and the relative preference were computed by pair-wise comparison of evaluation criteria given in hierarchial levels. The buffer zone width was determined by linear function of the given alternatives and relative preferences. From this study, it was determined that the six buffer zone widths of Kyoungan main stems would be 1,594, 1,744, 1,856, 1,782, 1,338, 1,780 meter, from upstream to downstream.

• Current Research on Agriculture and Life Sciences
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• 제27권
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• pp.69-75
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• 2009

This research regard it as most meaningful to realize the importance of the hedgerow in cultivated areas functioning as a residual landscape element in rural landscape and set improvement guidelines through landscape character and value analysis to cope with landscape malfunction. The results of summary are as follows. 1) First of all, as a result of landscape character analysis of edge stripe in cultivated land in total of 7 case areas, for example, the edge stripe in cultivated land in case area 4 and 8 maintain the width of 10m and are assessed satisfactory in terms of vegetation development condition, appearance of living species, connectivity, buffer capacity and so on. Also, as a result of structural character of correlation analysis among items, the correlation coefficient between width and appearance of living species showed 0.941, the highest. Following are connectivity and appearance of living species and width and buffer capacity respectively: 0.841 and 0.740. 2) As a result of landscape character analysis of uncultivated stripe in total of 6 case areas, it is analyzed that case area 4 maintains the widest width as almost 4.5m average width and considered valuable as I degree in vegetation development condition, filtering, and connectivity. 3) As a result of problem analysis of uncultivated stripe, for example, case 3, 9, and 10 was analyzed that the width was below 1.25m which is too small to carry out the function of buffer and habitat for living creature, so minimum standard width was set between 4~5m through comprehensive analysis of character of each case area. Based on the result above landscape character, value and problem analysis, main improvement guidelines are set in terms of width, connectivity, filtering, and vegetation development, restrictive practices and so on.

• 한국방재학회 논문집
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• 제8권4호
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• pp.111-118
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• 2008

수변완충지대는 토지로부터 나오는 오염물질의 하천으로 직접유입을 차단하고 저감하는 역할을 한다. 하지만 현재까지 수변완충지대 설정에 따른 유역에서의 저감효과를 분석하는 사례는 부족한 실정이다. 본 연구에서는 SWAT모형을 이용하여 Arcview GIS상에 병성천 유역 모형을 구축하고 SWAT모형에서의 filter strip기능을 이용하여 수변완충지대 설정에 따른 토사 유출량의 변화를 살펴보았다. 모의결과 저감효과가 큰 곳을 살펴보면 대체적으로 토사유출량 관측지점인 유역 출구지점과 가까운 소유역에서 저감효과가 큰 것으로 보였다. 또한 수변완충지대의 폭을 달리하여 시나리오 분석을 수행한 결과 5-10 m의 수변완충지대 폭이 그 저감효율이 가장 큰 것으로 보였다.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.439-444
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• 2005

We investigated the structural and electrical properties of BLT films grown on Si covered with $ZrO_{2}$ buffer layer. The BLT thin film and $ZrO_{2}$ buffer layer were fabricated using a metalorganic decomposition method. The electrical properties of the MFIS structure were investigated by varying thickness of the $ZrO_{2}$ layer. AES and TEM show no interdiffusion and reaction that suppressed using the $ZrO_{2}$ film as a buffer layer The width of the memory window in the C-V curves for the MFIS structure decreased with increasing thickness of the $ZrO_{2}$ layer. It is considered that the memory window width of MFIS is not affected by remanent polarization. Leakage current density decreased by about four orders of magnitude after using $ZrO_{2}$ buffer layer. The results show that the $ZrO_{2}$ buffer layers are prospective candidates for applications in MFIS-FET memory devices.

• 한국통신학회논문지
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• 제29권5A호
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• pp.514-520
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• 2004

WDM 네트워크에서 WDM 버퍼는 전광 패킷 스위칭 시스템을 구현하기 위한 핵심적인 요소 기술이다. 본 논문에서는 단일 루프형 전광 WDM 버퍼 구조를 제안하였으며, 이를 실험적으로 확인하였다. 제안된 구조는 NOLM과 피드백 루프로 구성되며, 제어 광 신호 (1553nm, 펄스 폭： 30㎱)에 의해 버퍼로부터 출력되기까지 단일 입력 펄스 (1550nm, 펄스 폭： 20㎱)를 약 40회 이상 버퍼링 (20${\mu}\textrm{s}$ 이상)할 수 있었다.

• 대한전자공학회논문지
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• 제25권5호
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• pp.509-521
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• 1988

In the designs of integrated circuits, the buffer circuits used for driving a large capacitive load from minimum-structured logic circuit outputs have important effects upon system throughputs. Therefore it is important to optimize the buffer circuits. In this paper, the principle of designing CMOS buffer circuits which have the minimum delay and drive the given capacitive load is discussed. That is, the effects of load capacitance upon rise time, fall time, and delay of the CMOS inverter and the effects of parasitic capacitances are finely analysed to calculate the requested minimum-delay CMOS buffer condition. This is different from the method by C.A. Mead et. al.[2.3.4.]which deals with passive-load-nMOS buffers. Large channel width MOS transistor stages are necessary to drive a large capacitive load. The effects of polysilicon gate resistances of such large stages upon delay are also analysed.And, the area of buffer circuits designed by the proposed method is smaller than that of buffer circuits designed by C.A. Mead's method.

• 한국물환경학회지
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• 제26권6호
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• pp.910-918
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• 2010

In recent years, riparian buffer system has been known as one of the effective best management practices. However, establishment of riparian buffer system in aspect of plant species and its position in the riparian buffer zone has not been investigated due to lack of efficient evaluation method for the analysis of water quality improvement with established riparian buffer system. To solve this problem, the SWAT-REMM prototype was developed by the researchers in Canada. But, SWAT-REMM model can not consider the $NO_3-N$ load into riparian buffer system through subsurface flow. Thus to solved this problem, Fortran code of SWAT-REMM model was modified. This modified SWAT-REMM system was applied to the Bonggok watershed. Three riparian buffer scenarios, 15 m, 10 m, 5 m width for tree and grass, were made to evaluate the effects of riparian buffer system on water quality improvement. Reduction efficiency of T-N by riparian buffer system of 15 m wide was the greatest (6 ~ 37%, depending on subwatershed characteristics) among 3 scenarios. It indicates that the reduction efficiency of T-N load has increasing-tendency, as buffer width increasing. The results obtained from the analysis showed that wide buffer zones are found to be more effective in reducing non-point pollutant than narrow buffer zones in the riparian buffer zone system. Hence, the SWAT-REMM model could be efficiently used for evaluation and design the most effective riparian buffer systems to reduce pollutant loads to the watershed although many limitations still exist in SWAT-REMM model.

• 동력기계공학회지
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• 제11권4호
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• pp.38-43
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• 2007

Pulsation is an inherent phenomenon in reciprocating compressors. It interacts with piping to cause vibrations and performance problems. Indiscriminately connecting to a compressor can be dangerous and cost money in the form of broken equipment and piping, poor performance, inaccurate metering, unwanted vibration, and sometimes noise. Piping connected to a compressor can materially affect the performance and response. To minimize these detrimental effects, reciprocating compressor system should be equipped by pulsation suppression system. The system usually comprises bottle volume, called snubber. Snubber is one of the most important parts in hydrogen compressing system. It has installed reciprocating hydrogen compressor. One of these components is snubber which has function to reduce pulsation waveform and to remove the impurities in the hydrogen gas. A snubber has an inclined plate as a buffer, which is installed inside snubber. When the pressure loss and the pulsation of pressure within a snubber is minimized, the snubber could get more applicability. Therefore, a study to find an optimum geometric size on a several snubbers which have different buffer width, has been conducted using a numerical analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.240-242
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• 1993

A novel structure, which can suppress latch-up phenomena, is proposed and verified by the PISCESIIB simulation. It is shown that this structure employing the selective N+ buffer layer increases latch-up current density due to suppression of the current flowing through the p-body. The width of the N+ buffer layer is optimized considering the trade-off between the latch-up current density and the forward voltage drop. The selective buffer layer results in an improved trade-off relationship compared with the uniform buffer layer.