• Korean journal of applied entomology
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• v.54 no.4
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• pp.369-374
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• 2015

Grapholita molesta (GM) has been considered as a major problem to apple and peach orchards. Mating disrupters have been applied to control the pest over the world as an Integrated Pest Management [IPM] tool. Various types of dispensers releasing mating disrupters have been developed with different formulation of wax, polyethylene tube and aerosol. In this study, the dispensers that were composed of ester waxes and polypropylene (PP) film were used as dispenser materials to analyze release pattern of GM pheromone compared with paraffin wax and polyethylene (PE) film. The release pattern in PP film group was consistent with time while PE film group irregular. Based on these results, Japan wax_PP film dispenser (Japan_PP) was manufactured and showed the mating disruption effect of 98% during 5months in peach orchard.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.173-177
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• 1998

Under indoor environment, in case that wireless optical LAN does not obtain the line-of-sight between transmitter and receiver, hemi-spherical lens or reflector must be adopted to get broader beam width. The beam tilt and the fluctuations in amplitude and phase of optical signal through indoor-space occur due to the turbulene. This fading often results in unacceptably large bit error probabilities and thus performance degradation of wireless optical communications. In this paper, when the spherical filter at the front-end of transmitter and receiver is used for wireless optical channel not satisfying line-of-sight, the signal-to-noise ratio as to zenithal angle and the effect from the turbulence due to indoor temperature are investigated.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.361-374
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• 2015

Endocirne disruptors (EDs) can cause fertility decrease, developmental disorder, and even cancer in animals. Until 90's, EDs were used in various synthetic products including paints, coatings, detergents, plastics, and plasticizers. Currently, in several countries, the production, trade and use of EDs or EDs-suspected chemicals have been regulated while activity to screen the alternatives for EDs including bisphenol-A, phthalate and nonylphenol is active. Although various toxicity test method was developed and applied for screening of alternatives, however, the safety of alternatives has been not fully demonstrated. Some alternatives have high structural similarity with existing EDs, raising the possible risk of endocrine disruption by alternatives. In an effort to develop the safe alternatives, we reviewed the effects of EDs such as bisphenol-A, phthalates, nonylphenol and their substituents. In addition, in-silico analysis for endocrine disrupting activities of some alternatives was presented.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.133-152
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• 1999

The cyclic triaxial test was carried out to research liquefaction characteristics and sample disturbance effects of silty sand soils at the west coast in Korea. First, liquefaction in silty sand was generated when axial strain approached to $\pm10%$ of strain and behavior of pore pressure was similar to the formula suggested by Seed, Martin, and Lysmer(1975). Also, it was found that dilatancy was generated at failure. Secondly, the liquefaction evaluation methods suggested by many researchers were carried out and the results were compared. In these methods the weak depth in liquefaction was similar and the method carried out by cyclic triaxial test on remolded sample showed the least safety factor. Thirdly the stress ratio by cyclic triaxial test was compared with that obtained from SPT N-value as a kind of empirical methods. It was found that the effect of sample disturbance was relatively small when SPT N-value was less than 20, but there were large differences in safety factor and resistance of liquefaction in soil by the effects of disturbance and remolding when SPT N-value was more than 20.

• Geotechnical Engineering
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• v.13 no.5
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• pp.45-58
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• 1997

In this paper the factors developing ground disturbance with the penetration of PDB mandrels are analysed by using field reconnaissance and laboratory test. In the laboratory tests, the amount of smear zones around the PDB mandrels is compared with respect to the shape and the size of mandrels by penetrating model mandrels of various shapes into the reconstituted clay. The shapes of mandrels selected are circular, oval and rectangular. It was recognized from the field reconnaissance that the size and shape, driving techniques of mandrels, as well as the size and shape of anchor shoe could develop ground disturbance. The mandrels that would reduce the smear effect of clay is oval and rectangular shapes rat her than circular one. It was found that the smear effect becomes smaller as the ratio of the long and short edge of the rectangular shape mandrel becomes larger.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.538-545
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• 2012

This study addressed soil disturbances following harvesting as well as soil physical and hydrological properties within three first-order headwater catchments characterized by ephemeral-intermittent streams. Four treatments representing a range of potential Best Management Practices(BMPs) for ephemeral-intermittent streams were used; BMP1, BMP2, clearcut and reference. This study includes 1 year of pre- and post-harvest observations. Results showed that post-harvest disturbances were closely related with harvesting intensity and generally tended to reflect changes in soil physical and hydrological properties following harvest with the except of bulk density and porosity. Forest clearcutting decreased macroporosity and saturated hydraulic conductivity, and increased soil resistence as a result of severe soil disturbances thereby increasing soil erosion. These impacts were reduced by implementing two BMP treatments during harvesting activities. The finding support the use of either BMP treatments for ephemeral-intermittent streams, however, the additional measure of leaving logging debris in BMP2 did not cover enough soil surface to reduce erosion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.944-951
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• 2011

This paper reports results of a joint experimental and numerical investigation of the causes of near-transducer errors due to the combined effect of acoustic and ADCP-induced flow disturbance near the ADCP transducer. The laboratory study focused on an isolated ADCP (deployment without boat). Measurements of the flow disturbance produced by the ADCP in vertical and horizontal planes were obtained acquiring measurements with an Acoustic Doppler Velocimeter (ADV). Concurrent measurements with ADCP and ADV were made to infer additional near-transducer effects in the ADCP measurements. The numerical investigation was designed to extend the inquiry on the near-transducer potential errors when the ADCP is deployed from a boat. Large Eddy Simulation (LES) was conducted to obtain the extent and magnitude of the disturbances induced by the drag acting on a boat-mounted ADCP and by the blockage effect of the instrument and boat. It is found the velocities measured by the ADCP are biased low and differ substantially from the undisturbed channel flow solution within a limited layer beneath the instrument.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.508-508
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• 2016

하천은 지형학적으로 청?장년기에 상 중 하류부가 구별되고 유량과 하상경사의 곱으로 표현되는 유수력(stream power)에 따른 반응으로서 구간별 수리 및 하도특성이 형성된다. 산지가 국토면적의 약 70%를 차지하고 노년기 지형인 유역을 기반으로 하며, 장마 및 태풍 내습시 집중호우에 따른 홍수발생으로 말미암아 대부분 국내의 하천은 상류는 산지, 중류는 곡저평야, 하류는 충적평야를 유하함으로서 구간별로 수리 및 하도 특성이 뚜렷이 구별된다. 홍수 예방을 위한 제방 축조와 용수공급을 위한 보 등 하천 구조물이 설치되어 있으며, 하천 주변에는 배산임수의 취락형성에 따라 주거지 및 대규모 도시가 발달하면서 많은 하천교란이 유발되고 있다. 우리나라 하도 및 수리적 특성인 여울과 소 등의 미지형과 하상매몰도 등 서식환경의 특성 및 하안에 적용되고 있는 다양한 형태의 하천횡단 형상과 하도개수 등 교란 특성을 중점적으로 고려하여 하천의 물리적 특성을 정량적으로 평가할 수 있는 평가체계를 개발하였다. 하도의 물리적 특성은 유량과 하상경사를 매개변수로 하는 유수력에 의하여 변화하므로 하천 유형을 하상경사에 따라 세그먼트 분류법을 적용하여 세그먼트 M, 세그먼트 1 및 세그먼트 2,3으로 구분하고 세그먼트별 하도 및 수리 특성, 하안 및 하천교란 영역에 대한 총 10개의 정량적 평가지표를 개발하였다. 각 지표는 5등급으로 설정되어 있으며, 평가지표의 근거는 미국(EPA) 및 독일(LAWA)의 평가지표를 바탕으로 우리나라 실정에 맞게 수정하였다. 본 연구에서는 하천분류체계에 의한 하천유형의 차이를 고려할 수 있도록 개발된 하천 물리적 평가체계를 남강, 내성천, 갑천, 유등천에 적용하여 검증하고, 적용성을 평가하였다. 우리나라 하천환경의 고유한 특성을 고려한 물리적 하천환경 평가체계는 하천사업을 위한 현재의 하천환경의 진단 및 하천사업의 효과 및 분석 등에 활용할 수 있으며, 하천관리를 위한 지구지정의 정량적 기준 및 관리목표 설정 등 하천계획 설계의 실무과정에서 매우 유용하게 적용될 수 있을 것으로 판단된다.

• Proceedings of the KGS Conference
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• 2003.11a
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• pp.95-99
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• 2003

20세기의 경제사회는 대량생산, 대량소비, 대량폐기의 일방통행(one-way)이 기본이었다. 그러나 이러한 시스템에서 많은 양의 폐열과 폐기물이 발생함으로서 유해물질, 온실효과에 의한 생태계의 교란을 가져와 인간의 생명활동에 위협을 주게 되었다. 이에 따라 인간사회에서 발생하는 폐열과 폐기물을 가능한 한 적게 발생시키고 자원이나 에너지를 자연에서 얻어 인간사회에 제공하되 가능한 한 적게 사용하는 사회로의 전환이 추구되어야 한다. (중략)

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.170-173
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• 1997