• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1299-1308
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• 2023

Carya cathayensis is an important economic nut tree that is endemic to eastern China. As such, outbreaks of root rot disease in C. cathayensis result in reduced yields and serious economic losses. Moreover, while soil bacterial communities play a crucial role in plant health and are associated with plant disease outbreaks, their diversity and composition in C. cathayensis are not clearly understood. In this study, Proteobacteria, Acidobacteria, and Actinobacteria were found to be the most dominant bacterial communities (accounting for approximately 80.32% of the total) in the root tissue, rhizosphere soil, and bulk soil of healthy C. cathayensis specimens. Further analysis revealed the abundance of genera belonging to Proteobacteria, namely, Acidibacter, Bradyrhizobium, Paraburkholderia, Sphaerotilus, and Steroidobacter, was higher in the root tissues of healthy C. cathayensis specimens than in those of diseased and dead trees. In addition, the abundance of four genera belonging to Actinobacteria, namely, Actinoallomurus, Actinomadura, Actinocrinis, and Gaiella, was significantly higher in the root tissues of healthy C. cathayensis specimens than in those of diseased and dead trees. Altogether, these results suggest that disruption in the balance of these bacterial communities may be associated with the development of root rot in C. cathayensis, and further, our study provides theoretical guidance for the isolation and control of pathogens and diseases related to this important tree species.

• Earthquakes and Structures
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• v.26 no.5
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• pp.401-416
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• 2024

Long-span structures, such as bridges, can experience different seismic excitations at the supports due to spatially variability of ground motion. Regarding current bridge designing codes, it is just EC 2008 that suggested some regulations to consider it and in the other codes almost ignored while based on some previous studies it is found that the effect of mentioned issue could not be neglected. The current study aimed to perform a comprehensive study about the effect of spatially varying ground motions on the dynamic response of a reinforced concrete bridge under asynchronous input motions considering soil-structure interactions. The correlated ground motions were generated by an introduced method that contains all spatially varying components, and imposed on the supports of the finite element model under different load scenarios. Then the obtained results from uniform and non-uniform excitations were compared to each other. In addition, the effect of soil-structure interactions involved and the corresponding results compared to the previous results. Also, to better understand the seismic response of the bridge, the responses caused by pseudo-static components decompose from the total response. Finally, an incremental dynamic analysis was performed to survey the non-linear behavior of the bridge under assumed load scenarios. The outcomes revealed that the local site condition plays an important role and strongly amplifies the responses. Furthermore, it was found that a combination of wave-passage and strong incoherency severely affected the responses of the structure. Moreover, it has been found that the pseudo-static component's contribution increase with increasing incoherent parameters. In addition, regarding the soil condition was considered for the studied bridge, it was found that a combination of spatially varying ground motions and soil-structure interactions effects could make a very destructive scenarios like, pounding and unseating.

• Journal of Environmental Health Sciences
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• v.43 no.3
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• pp.233-239
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• 2017

Objectives: The pollution status of heavy metals within the soil was investigated with an aim to establishing a sustainable soil environment within parks and amusement facilities installed in urban areas of Gyeonggi-do Province. Methods: As sampling sites, 14 locations were selected from a city with a number of factories near a residential area, a residential area, and a children's park in a city with mixed green areas. Seven kinds of heavy metals, including Cd, Pb, and Hg, and the pH of soil were analyzed three times by inductively coupled plasma optical emission spectroscopy (ICP-OES) and atomic absorption spectrometer (AAS). Results: In this study, the pH of the samples from the residential park and industrial park showed 5.7-6.5 and 5.9-7.0, respectively. The overall mean concentration (mg/kg) of heavy metals was Zn (132.8), Ni (73.0), Cu (47.4), Pb (35.9), As (4.84), Cd (0.39), and Hg (0.07), indicating that these concentrations of heavy metals were lower than those for the area 1 standard of soil pollution concern criteria. In addition, the sampling sites in the residential area and the industrial area also showed the same tendency for concentration distribution. Conclusions: We found that the soil pollution class (SPC) of some spots were over 200, which are third and fourth classes. In order to manage a sustainable soil environment in a city park, it is suggested that local governments, the management bodies for these parks, need to manage, supervise, and investigate soil pollution and quickly replace contaminated soil.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.57-70
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• 2008

The advantage of piezocone penetration test is a guarantee of continuous data, which is a source of reliable interpretation of target soil layer. Many researches have been carried out f3r several decades and several classification charts have been developed to classify in-situ soil from the cone penetration test result. Since most present classification charts or methods were developed based on the data which were compiled over the world except Korea, they should be verified to be feasible for Korean soil. Furthermore, sometimes their charts provide different soil classification results according to the different input parameters. However, unfortunately, revision of those charts is quite difficult or almost impossible. In this research a new soil classification model is proposed by using fuzzy C-mean clustering and neuro-fuzzy theory based on the 5371 CPT results and soil logging results compiled from 17 local sites around Korea. Proposed neuro-fuzzy soil classification model was verified by comparing the classification results f3r new data, which were not used during learning process of neuro-fuzzy model, with real soil log. Efficiency of proposed neuro-fuzzy model was compared with other soft computing classification models and Robertson method for new data.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.6
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• pp.19-28
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• 2004

Segmental Retaining Wall(SRW) has been variously applying in Civil and Architecture construction. Recently, the application of environmental element in all type's structures came to essential requirement, and the construction cases of retaining wall using reinforced soil and block are more increased than the past. But, this trend more widely was spread environmental element as landscape work for the backside of reinforced retaining wall as well as block itself. New environmental block, Greenstone Block, developed to apply of this tendency. The retaining wall system using Greenstone can be environmental constructing at both block itself and backside of retaining wall. The material tests, the axial compressive strength test of block and bending test of fiber-pipe, exercised to design and construction of vertical SRW, which were satisfied NCMA standard. Through this procedure, Rewall (ver 1.0) was developed, which can be automation design of SRW including internal stability, external stability and local stability. And these can be considered setback of retaining wall, as well the examples of vertical retaining wall using block presented to satisfying the follows; strength of reinforced geotextile, height of retaining wall, surcharge, types of backfill and groundwater level etc. Many problems investigated on after or before of construction were due to local failure, insufficiency of bearing capacity and groundwater level. Especially, the local failure was many occurred to during compaction or after construction, and the cases of SRW construction is similar to the results of model test on vertical SRW.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.71-77
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• 2008

Microstructural changes may arise due to the particle vanishing, fluid diffusion, heating, etc. This study focuses on the changes in small-strain shear stiffness in k0 loading produced by local straining in particular system made of sand-salt mixtures. Local strains were induced by dissolution of salt particles. Experiments were carried out in a conventional oedometer cell equipped with bender elements. Axial displacement and shear wave signals are recorded at each loading stage and during saturation process. Experimental data showed that microstructural changes due to particle vanishing were clearly captured by using shear wave measurement. Saturation of sand-salt mixture at a larger axial stress did not always create a more condense soil at the end of loading stage. Sand-salt mixture is useful for laboratory test on controlled artificial specimen.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2381-2384
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• 2008

The heat exchange between the Borehole Heat Exchanger(BHE) and the surrounding ground depends directly on ground thermal conductivity k at the certain site. The k is thus a key parameter in designing BHE and coupled geothermal heat pump systems. Currently, although a thermal hydraulic Response Test(TRT) is mostly used in practice, the thermal hydraulic TRT needs additional power and is generally time-consuming. A new, simple wireless probe for hi-speed k determination was introduced in this paper. This technique using a wireless probe is less time-consuming and requires no external source of energy for measurement and predicts local thermal properties by measuring soil temperatures along the depth. Measured temperature data along the depth was analyzed. As a result, the electronic wireless probe can replace the conventional hydraulic TRT method after carrying out the additional research on a lot of local heat flow, etc.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.268-274
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• 2010

The properties of upland soils are much more dependent upon topography than those of paddy soils, and they give us very useful information to manage the upland fields. Therefore, we investigated the selected physical and chemical properties of upland soils at 84 and 150 topographic sampling sites, respectively. The topographic sites included 34.7% of local valley and fans, 18.7% of hilly and mountains, 20.0% of mountain foot slopes, 14.0% of alluvial plains, 8.0% of diluvium, and 4.6% of fluvio-marine deposits. Based on the investigation, soil textures in Jeonbuk upland fields were mostly sandy loam, sandy clay loam, clay loam, and clay soils, especially sandy clay loam soils were evenly distributed in all of the topographic sites. Soil slopes in the sites ranged from 0 to 15%, which showed an optimal condition for farm land. Soil bulk density and compaction values were from 1.19 to 1.24 g $cm^{-3}$ and from 12.1 to 13.9 mm, respectively. As comparing with the optimal conditions of soil chemical properties for upland soils proposed by National Institute of Agricultural Science and Technology, Korea, 37%, 42.7%, 93.0% of the sites were within optimum levels with soil pH, content of soil organic matter, and electrical conductivity, respectively. However, 64.0%, 47.3%, 48.7%, and 42.7% of the upland soils contained excess levels of exchangeable K, Ca, and Mg, and available phosphorus, respectively. In addition, the contents of heavy metals, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, in the Jeonbuk upland soils were much less than threshold levels.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1829-1836
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• 2010

The district heating system distributes the heat generated from a cogeneration plant to wider locations. In this process, the district heating pipe (DHP) is subjected to internal and external loadings. The internal loadings are generally caused by the operating conditions such as water temperature and internal pressure. Frictional interactions between the pipes and the soil contribute to the external loadings. Thus, investigation of the mechanisms of failure of DHPs will help to guarantee both mechanical stability and heating efficiency. In this study, we investigate the local buckling of DHPs using limit state design (LSD). Two methods are considered: the use of the limit state for the width-thickness ratio and the use of the limit state for the strain. The results are used to confirm that the DHP is stable under local buckling. Finally, we suggest a minimum preheating temperature for avoiding local buckling.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.861-866
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• 2002

This manuscript introduces the Capacity Design Methodology in the Building Standard Law of Japan revised at 2000, June. The Building Standard Law of Japan was revised into the performance-based design format following the trend of international. The structural performance was evaluated for two limiting states; soundness limit state and safety limit state. The design seismic forces were determined on taking into consideration (a)the properties of the planned building, (b)amplification by local surfaces geology, and (c)soil-structure interaction.