• 한국주거학회논문집
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• 제24권3호
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• pp.45-53
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• 2013

It is important to secure green spaces to solve the urban heat island phenomenon, which is among problems resulted by high-density developments in metropolitan areas. However, it is hard to secure such green spaces in established urban areas so Green Rooftop development approaches have recently been highlighted and introduced as a solution to the situation. The present study conducts a simulation on residential areas in urbanized regions to quantitatively evaluate the effects of green rooftop developments through a comparison of changes in the air temperatures before and after relevant development projects. According to the evaluation results, when the green roof top development is conducted in the available areas, the temperature is reduced by 0.14 degree. The extension of green project to the entire building showed the reduction of the temperature by 0.29 degree. Based on these results, it can be concluded that the green rooftop development is a practically solution for reducing the air temperature of urbanized areas.

• 한국작물학회지
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• 제53권4호
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• pp.413-416
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• 2008

The cultivation of green manure crop is considered as a good management practice by increasing soil organic matter and fertility levels. This experiment was conducted to improve the soil environment under rice-based cropping system at paddy soil (fine loamy, mixed, nonacid, mesic, family of Aeric Fluventic Haplaquepts) in National Institute of Crop Science (NICS), Korea in 2006 to 2007. The variation of soil temperature in green manure plots was lower than without green manure (control) during spring season (April to May). The temperature variation of no tillage plot (broadcast before rice harvest) was the lowest among treatments. After green manure cropping, the soil bulk density and porosity ratio were improved at the top soil. The production of green manure was the highest athairy vetch and barley mixture plot by partial tillage. However, mixture treatment had no improvement on soil organic matter. After rice cropping with green manure application, soil quality was improved such as soil physical properties except mixture treatment. Therefore, we suggest that soil quality should be improved by green manure cultivation under rice-based cropping system.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.565-572
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• 2021

Hydrogen is currently produced from natural gas reforming or industrial process of by-product over than 90%. Additionally, there are green hydrogens based on renewable energy generation, but the import of green hydrogen from other countries is being considered due to the output variability depending on the weather and climate. Due to low density of hydrogen, it is difficult to storage and import hydrogen of large capacity. For improving low density issue of hydrogen, the gaseous hydrogen is liquefied and stored in cryogenic tank. Density of hydrogen increase from 0.081 kg/m³ to 71 kg/m3 when gaseous hydrogen transfer to liquid hydrogen. Density of liquid hydrogen is higher about 800 times than gaseous. However, since density and boiling point of liquid hydrogen is too lower than liquefied natural gas approximately 1/6 and 90 K, to store liquid hydrogen for long-term is very difficult too. To overcome this weakness, this paper introduces storage method of hydrogen based on liquid/solid (slush) and facilities for producing slush hydrogen to improve low density issue of hydrogen. Slush hydrogen is higher density and heat capacity than liquid hydrogen, can be expected to improve these issues.

• 한국세라믹학회지
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• 제26권3호
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• pp.347-360
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• 1989

Spinel, mullite, forsterite and cordierite composition powders were synthesized from Mg(NO3)2.6H2O, Al(NO3)3.9H2O and SiCl4-ethanol solution by spray pyrolysis method and the sinterability of these powders were investigated. The bulk density of spinel and mullite specimens sintered at 1,$700^{\circ}C$ for 1hr was 3.56g/㎤(99.5% relative density) and 3.16g/㎤(99.7% relative density), respectively. (Green compacts were made from powders prepared at 1,00$0^{\circ}C$). The bulk density of forsterite and cordierite specimens sintered at 1,480 and 1,40$0^{\circ}C$ for 2hrs were 3.217 and 2.155g/㎤, respectively. (Green compacts were made from powders prepared at 1,00$0^{\circ}C$). The constituent compositions of spinel and mullite specimens sintered at 1,$700^{\circ}C$ for 1hr were 27.5wt% MgO and 70.5wt% Al2O3, respectively. Vickers microhardness and fracture toughness of spinel sintered at the above condition were 13.7GPa and 2.6MN.m3/2, respectively, and room temperature bending strength, 425MPa, was nearly maintained even at the elevated temperature. In the case ofmullite specimens, those values were 13.5GPa, 2.2MN/m3/2 and 430MPa, respectively.

• 환경영향평가
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• 제32권6호
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• pp.437-449
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• 2023

본 연구는 도로변에 위치한 완충녹지와 근린공원에서 미세먼지 농도와 풍속을 실측하고, 이를 도로 측 측정결과와 비교분석하여 녹지 유형별 미세먼지 농도 저감 효과와 그에 대한 풍속의 영향을 파악하고자 하였다. 분석결과 도로변 녹지 유형에 따라 미세먼지 농도 저감 효과가 달랐고, 풍속의 증가는 미세먼지 농도 감소에 유의한 영향을 주었다. 식재밀도가 높은 완충녹지에서는 풍속이 낮고 내부에 미세먼지가 정체되어 미세먼지 농도가 가장 높았다. 반면 식재밀도가 상대적으로 낮은 근린공원 내 녹지지역은 풍속이 높고 미세먼지 농도가 가장 낮았다. 근린공원 내 비녹지지역은 가장 높은 풍속을 기록하여 미세먼지 확산에 유리하였으나 녹지지역보다 미세먼지 농도가 높았다. 따라서 도로변 녹지 내 미세먼지 농도 감소를 위해서는 바람 흐름이 원활한 녹지를 조성해야 하며, 높은 풍속과 수목의 저감 기능의 복합적인 작용이 미세먼지 농도 감소에 더 유리한 것으로 판단되었다. 녹지는 내부에 미세먼지를 포착·제거하여 외부 미세먼지 농도 감소에 기여한다. 도시 전체 및 도로 미세먼지 관리를 위해서는 완충녹지와 같은 도로변 녹지에서 식재밀도나 엽면적 등을 높여 미세먼지가 녹지 내에서 제거될 수 있도록 유도해야 한다. 그러나 도시민의 이용이 활발한 근린공원과 같은 녹지에서는 내부 미세먼지가 외부로 확산이 잘 될 수 있는 구조의 녹지를 조성하여 미세먼지로 인한 이용자의 피해를 최소화하는 것이 바람직하다.

• 한국토양비료학회지
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• 제43권1호
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• pp.105-112
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• 2010

벼 유기농업은 한국에서 빠르게 확산되고 있다. 유기재배에서 벼 생육은 토양 물리적 특성과 토양 미생물의 기능에 크게 의존한다. 본 연구는 무경운 답에서 유기농업을 위하여 토양 물리성과 미생물 생체량에 미치는 녹비작물의 효과를 검토하였다. 시험구는 무경운, 무경운+볏짚, 무경운+호밀, 무경운+자운영 그리고 경운구를 3반복으로 죽곡통에서 2005년 5월에서 2006년 10월까지 수행하였다. 경운구는 2005년과 2006년 모두 토양 가밀도가 가장 높은 반면 공극률은 가장 낮았다. 무경운+호밀 처리구는 공극률이 가장 높았으며 무경운 처리구의 표토 관입저항은 경운구 보다 낮았다. 담수 전 2005년과 2006년 토양 미생물 생체량 탄소 함량은 무경운+자운영 처리구가 477 mg $kg^{-1}$ 및485 mg $kg^{-1}$으로 가장 높았고 무경운+호밀 처리구는 413 mg $kg^{-1}$ 및 484 mg $kg^{-1}$였으며 경운 처리구는 363 mg $kg^{-1}$ 및 445 mg $kg^{-1}$을 나타냈다. 시기적으로 토양 미생물 생체량 탄소 함량은 유수형성기에 낮아지는 경향이었다. 연구결과 녹비작물을 시용한 무경운 재배기술은 경운에 비해 토양 공극률과 토양 미생물 생체량 탄소 함량을 크게 개선하였다.

• 한국연초학회지
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• 제16권2호
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• pp.113-121
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• 1994

The green peach aphid was relatively the majority(36.9-72.3% ) among all alate aphids collected from tobacco plants. Density of glatae was relatively lower on varieties Tl 1112 and Br 21 than on Va 115 or Y S A among seven varieties tested. However, no considerable difference was observed in general biology of nymphs produced by alatae on the tobacco varieties. About 55% of alate green peach aphid collected from tobacco fields produced progency, and over 80% of the nymphs became adults on cut tobacco leaves in petri dish. Adult longevity of both alate and apteral green peach aphid was shorter, and numbers of nymphs produced by both types were lower in summer than in autumn. Apterae produced more nymphs than alatae, but the longevity of apterae was shorter.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.387-390
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• 2006

The protective layer of AC-PDP was fabricated by laminating an MgO green sheet. The MgO green sheet was made by coating MgO solution composed of solvent, dispersant, binder, and MgO nano-powder. The MgO solution was coated by the die casting method on the base film. We fabricated three kinds of MgO green sheets of which thicknesses were 20, 28, and $40\;{\mu}m$, respectively. The MgO nano-powder showed lower CL intensity and ${\gamma}i$ than the e-beam MgO. The MgO green sheet applied panels showed low luminance and current density. The efficiency was almost same as the conventional e-beam MgO panel.

• 한국전기전자재료학회논문지
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• 제19권12호
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• pp.1112-1117
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• 2006

The properties of LTCC green tape with addition of binder were investigated in order to understand an effects of binder on multilayer processing. A green sheet form was fabricated through tape casting method with the MLS-22 powder. The lamination density increased with increasing amount of binder and lamination pressure. With increasing amount of binder, the elongation of ceramic sheets increased but the tensile stress and air-permeability decreased. The addition of excessive binder is caused defects in the green sheet during via hole punching. The optimum condition of the via hole without defects was observed from amount of the binder 10 wt%.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.731-732
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• 2006

Recently warm compaction techniques are focused on and commercialization of one high-density compaction process in the P/M industry. Another development is a new SEGLESS using a developed lubricant that reduces ejection force at room temperature compaction. It is possible to achieve high-density by reducing lubricant amount. In this paper we confirmed that green density was $7.35g/cm^3$ at 686MPa of compaction pressure when the new SEGLESS was applied to relatively lower temperature warm compaction process, such as $80^{\circ}C$.