• Proceedings of the Korean Geotechical Society Conference
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• 2000.09a
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• pp.35-38
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• 2000

Reflection cracks can be occurred in the asphalt layer overlaid on portland cement concrete pavements, because this layer is sensitive to environmental conditions including temperature changes and displacements of the pavement. A result of trial applications using glass fiber grids is introduced in this paper. Glass fiber grids were used between the asphalt layer and the concrete base to reduce the reflection crack of the asphalt layer. No cracks were observed in the glass grid installed area about 2 years later from trial constructions.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.123-129
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• 2000

This study was conducted to analyse the distribution of root-knot nematodes (Meloidogyne spp.) in fruit vegetable production areas in Korea. Soil samples were collected from greenhouses in Sungju (Kyungpook), Yeoju (Kyungki), Haman (Kyungnam), and Chungwon (Choongpook) provinces in 1997-1999. Plant parasitic nematodes were separated for density counting and some of the root-knot nematodes were identified using enzyme phenotypes of malate dehydrogenase (MDH) and esterase (EST). Among the 185 farms in Sungju province, Meloiciogyne spp. were detected from 99 farms (53.5%). Other plant parasitic nematodes detected were; Helic~otylmchuss pp. from 7 farms, Aphelenchus spp. from 43 farms, and Criconematids from 26 farms. Using the female enzyme phenotypes of MDH and EST. the four major root-knot nematodes in Korea, M. incognitc~(M I), M. uretznri~(M~ A), M. huplu (MH), and M. juvunica, could be identified. In the enzyme phenotype identification of 13 populations collected from Sunnam in Sungju province, 6 populations were identified as MA, 5 populations were identified as MI, and 2 populations were mixed with MI and MA. Among the 6 populations from Chojun in Sungju province. 4 populations were MA, one population was MI, and one population showed enzyme phenotypes of unknown species. Among the 14 populations of Yeoju province, l I populations were MH and 3 populations were MA.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.224-233
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• 2016

Embedded Railway Systems (ERS) will be adapted for wireless trams and will be constructed along city roadways. An asphalt layer should be overlaid on top of the concrete slab used as the trackbed structure in order to ensure smoothness and surface levels equal to those of existing road pavement in downtown city areas. However, the characteristics of an asphalt layer when used as overlay pavement for an ERS are complicated and the behavior of this material is not yet well defined and understood. Therefore, in this study, laboratory shear and tensile bond strength tests were conducted to investigate the bonding behavior of an asphalt layer in a multilayered trackbed section of an ERS. For the laboratory tests, a waterproof coating material was selected as a bonding material between the asphalt overlay and a concrete specimen. Valuable design parameters could be obtained based on the tensile and shear bond strength test results, providing information about the serviceability and durability of the overlaid pavements to be constructed alongside the ERS for wireless trams. In addition, a deformation analysis to assess the tensile strain generated due to truck axle loads at the interface between the asphalt layer and the concrete slab was conducted to verify the stability and performance of the asphalt layer.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.19-28
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• 2012

A measuring technique for tire-pavement interaction noise that uses a proposed noble close proximity(NCPX) method, which has been proofed in terms of the reliability and consistency of interaction noise measurement through several researches, equipped with surface microphones has been adopted in order to perform bridge deck pavement noise evaluations on four different pavement surfaces. Through field testing measurement of bridge deck pavement in Seoul inner ring road, the appropriate noise-measuring procedures have been used for evaluating the noise characteristics of four different surfaces. Measuring results show that tire-pavement noise levels vary depending on the surface types and vehicle speeds. Furthermore, the different characteristics of tire-pavement interaction noise can be found before and after the new surface construction of bridge deck pavements in terms of the 1/3 octave band analysis of vehicle speed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.73-82
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• 1989

Various analytical procedures for the structural behavior of concrete pavement system are studied in order to identify a suitable method which will be incorperated in the pavement management system using nondestructive test and mechanistic evaluation. A typical four layered system is adopted and analyzed using 3 dimensional finite elements, plane strain elements, plates with Winkler foundation, and plates with Burmister foundation. Numerical analysis results of various structural analysis procedures are compared and analized based on displacements and stresses. It is concluded, after analysis of merits and demetits of the procedures, that Burmister foundation analysis procedure is the most sui-table procedure for implementation for the analysis of stresses and displacements because of its accuracy and simplicity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.352-356
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• 1997

In order to trace the survival route of weedy rice in Korean farmer's field, occurrence rate and position of weedy rice, number of weedy rice plants per $m^2$, in transplanted and direct seeded field were investigated. The highest occurrence rate of weedy rice in transplanted field was 5.5％. Number of weedy rice plants in direct seeded field was higher than that in transplanted field. In transplanted field, most of the weedy rice were grown within hills of cultivated rice and only a few was grown between hills of the cultivated rice, however in direct seeded field the number of weedy rice occurred between hills or rows of cultivated rice was higher than that occurred within hills or rows. Weedy rice occurrence rate in the field of .non-recommended rice variety was higher than that in the field of recommended variety. The main survival route of weedy rice in transplanted field was supposed to be mixture of weedy rice seeds with cultivated rice, and that in direct seeded field to be natural survival.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.8 no.4
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• pp.101-109
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• 1987

포도나무에 발생하는 병(病)은 현재 19종(1986)이 알려져 있으며, 병 발생의 중요도가 여러 가지 요인의 변화에 따라서 바뀌고 있다. 그 요인을 우선 약제사용면에서 보면 약제종류의 변화, 살포방법의 변화, 살포회수의 변화 및 포장위생의 불철저 등을 들 수 있고 재배적인 면에서 보면 품종의 변천, 재배형의 변화, 시비방법의 변화 등을 들 수 있다. 또 해와 지역에 따라서는 이상저온, 다우다습(多雨多濕), 건조 등 기상 조건이 변함에 따라서도 병의 발생은 크게 달라 진다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.181-181
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• 2011

도로는 국내 물류를 담당하는 중요한 기반시설로 국내 경제성장의 중추적인 역할을 담당하고 있다. 특히, 1970년대 개통된 경부고속도로는 우리나라의 대동맥으로 산업 성장의 파급효과를 가져오는 기반이 되었고, 공학적인 차원에서도 도로 포장재료를 경험 및 과학적으로 분석하여 적용하는 계기로 도로공학발전의 초석이 되었다. 과거에 적용된 도로 포장재료는 기술자의 경험에 의존하여 배합설계가 진행되었으며, 중차량의 비중이 많은 지역은 강성포장을 적용하고, 상대적으로 중차량이 적은 구간은 연성포장을 적용하는 설계를 따랐다. 하지만, 강성포장을 대표하는 시멘트 콘크리트 포장은 시공상의 복잡함과 시멘트 콘크리트 특성상 강도발현을 위해서 일정기간 이상의 양생일수가 필요하므로, 도로건설의 인프라 구축이 시급한 지역에서는 사용의 제약이 따른다. 연성포장을 대표적하는 재료로는 아스팔트 콘크리트 포장을 들 수 있다. 강성포장보다는 상대적으로 시공상의 편리함과 일정기간의 양생이 필요하지 않아 도로 포장재료로서 그 적용성이 우수하다. 과거에는 아스팔트 콘크리트 포장의 종류가 단순화되어 표층, 기층에 대표되는 몇몇 혼합물이 도로 포장재료로 사용되었다. 도로공학의 학문적 발달과 함께 도로포장의 전반적인 기술이 향상되고 있다. 과거의 도로 기능은 국가 경제발전을 위한 산업용 원자재의 운반이 주요 기능을 담당하고 있는 반면, 국민의 경제적 수준이 증대되고 자가용의 보급이 보편화되면서 도로 이용의 주체가 국민 개개인으로 변화되고 있고, 그 요구조건도 다양화되고 있다. 이에 발맞추어 도로공학의 기술적 향상으로 다양한 기능을 발휘할 수 있는 도로포장재료가 개발되고 있으며, 대표적인 제품으로는 배수성 포장, 반강성 포장, 보수성 포장, 탄성 포장, 저소음 포장 등이 있다. 본 연구에서는 기능성 포장의 하나인 저소음 포장의 특성 중 생산성능을 평가하였다. 생산성능이란 저소음포장을 현장 플랜트에서 생산하였을 경우의 특성을 분석하는 과정으로, 실내 실험으로 최적화된 재료의 배합은 이상적인 조건을 적용하여 결정된 것으로 입고된 현장 골재 및 생산 플랜트 조건에 따른 그 배합 및 물성이 변동을 가져올 수 있다. 특히, 저소음 포장은 기존의 아스팔트 포장과 달리 적용되는 골재, 아스팔트의 재료가 고성능을 발휘하기 위하여 특수한 재료를 적용해야 한다. 배합설계에서도 개립도 아스팔트 혼합물에 적용되는 내구성분석 절차를 따라야 하므로, 실내 배합설계 혼합물과 현장 생산 혼합물간의 물리적 특성에 차이를 나타낼 수 있다. 따라서, 본 연구에서는 실내 및 현장 혼합물의 전반적인 물리적 특성의 차이를 분석하여 저소음 포장의 현장 생산성능을 확인하였다. 분석요소로는 혼합물의 기초물성면에서는 밀도, 공극률을 분석하였으며, 실내 내구성면에서는 마샬안정도, 잔류안정도를 분석하여 실내 및 현장 혼합물의 물성차이를 분석하였다. 기초물성을 평가할 수 있는 밀도와 공극률에서는 생산 현장 혼합물이 실내 혼합물 보다 높은 밀도와 낮은 공극률을 나타내고 있으며, 이에 상관하여 강도특성을 분석할 수 있는 마샬안정도도 생산 현장 혼합물이 다소 높은 강도를 발휘하였다. 또한, 수분에 대한 안정성을 평가하는 인자인 잔류 안정도에서는 실내 및 현장 혼합물 모두 우수한 성능을 발휘하였다.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.114-122
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• 2017

N-nitrosamines can be produced in the process of heating, processing, storage and packaging. Migration specifications for N-nitrosamines exist only for rubber baby bottle nipples, which are regulated by the Ministry of Food and Drug Safety (MFDS). There is no regulation for other food contact substances (FCS) and studies on N-nitrosamines migration from FCS are rather limited. A pilot study showed an increase in N-nitrosamines contents when cooking instant noodles. Thus, the migration from the packaging was suspected and it was necessary to monitor the migration of N-nitrosamines from food packaging materials and to examine the change in N-nitrosamines contents when cooking instant foods. Three N-nitrosamines, NDMA (N-nitrosodimethtlamine), NDEA (N-nitrosodiethylamine), NDBA (N-nitrosodibutylamine), were analyzed in migration test solutions from plastics such as polyethylene, polypropylene and polystyrene, papers and aluminium containers. In all test solutions, N-nitrosamines were detected less than method quantitation limits (MQLs). Food samples were also investigated to ensure that there is no effect from food contact substances when cooking instant foods. In retort sauces such as curry, black soybean sauce and tomato sauce, NDMA concentration was ranged from 0.54 to $3.81{\mu}g/kg$, but there were no significant differences between unheated and heated samples. However, the NDMA contents were significantly increased in most of the instant noodle samples tested when cooked (p < 0.05). No effects from the food contact substances or cooking water was observed. Only when the seasoning powder and noodles were cooked together was NDMA detected. Individual components (noodle, seasoning powder or dried vegetable) or other combinations such as noodles and dried vegetables did not generate N-nitrosamines. Therefore, it is speculated that NDMA may be formed from the precursors in noodles and seasoning powders when they are solubilized in a medium of water.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.31-38
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• 2011

As the percentage of permeable ground is reduced due to the increased impermeable roads of major cities, a heat island phenomenon can be dominantly observed, resulting in increased temperature. In addition, rainfall that would have been naturally absorbed and retained by the permeable ground is overflowed due to large volumes of run-off water, resulting in more sewer failures and increased erosion. In terms of permeable pavement system, block paving has been used anywhere as well as provides many years of service. The permeable block paving is an effective alternative to the more traditional asphalt or plain concrete for minor roads; furthermore, it looks a lot better than other pavements. In this study, the functional drainage evaluation of block paving was carried out, considering the usage of experimental sludge and wheel tracking test, in order to simulate the field condition of roads.