• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.129-138
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• 2006

Helicopter-borne aeromagnetic surveys at two different times separated by three years were conducted to better understand the shallow subsurface structure of the Vulcano and Lipari volcanic complex, Aeolian Islands, southern Italy, and also to monitor the volcanic activity of the area. As there was no meaningful difference between the two magnetic datasets to imply an apparent change of the volcanic activity, the datasets were merged to produce an aeromagnetic map with wider coverage than was given by a single dataset. Apparent magnetisation intensity mapping was applied to terrain-corrected magnetic anomalies, and showed local magnetisation highs in and around Fossa Cone, suggesting heterogeneity of the cone. Magnetic modelling was conducted for three of those magnetisation highs. Each model implied the presence of concealed volcanic products overlain by pyroclastic rocks from the Fossa crater. The model for the Fossa crater area suggests a buried trachytic lava flow on the southern edge of the present crater. The magnetic model at Forgia Vecchia suggests that phreatic cones can be interpreted as resulting from a concealed eruptive centre, with thick latitic lavas that fill up Fossa Caldera. However, the distribution of lavas seems to be limited to a smaller area than was expected from drilling results. This can be explained partly by alteration of the lavas by intense hydrothermal activity, as seen at geothermal areas close to Porto Levante. The magnetic model at the north-eastern Fossa Cone implies that thick lavas accumulated as another eruption centre in the early stage of the activity of Fossa. Recent geoelectric surveys showed high-resistivity zones in the areas of the last two magnetic models.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.86-94
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• 2014

Survey was carried out in paddy fields to investigate the dominance of weed species and weed occurrence on 200 fields of southern Gyeonggi region in Korea during the year 2013. We observed 3 species of grass, 5 species of sedge, and 11 species of broadleaf and other weeds. The most dominant weed species was Eleocharis kuroguwai, followed by Echinochloa crus-galli, Sagittaria trifolia, Monochoria vaginalis, Scirpus juncoides and Bidens tripartita. The dominance value of E. kuroguwai and B. tripartita decreased compared to the survey results performed in 2005 but that of M. vaginalis, S. juncoides, S. trifolia and E. crus-galli increased. Weed occurrence increased from 2.83 g in 2005 to 3.51 g in 2013 based on weed dry weight per $m^2$. Occurrence ratio of annual weeds to perennial weeds changed from 45.2% : 54.8% in 2005 to 45.8% : 54.2% in 2013. If we analyze dominance of weed species based on the rice transplanting timing, E. kuroguwai and E. crus-galli were the most dominant weed species at mid-May transplanting, and M. vaginalis and S. juncoides were the most dominant weed species at late- May transplanting, and M. vaginalis and E. kuroguwai were the most dominant weed species at early-June transplanting. Since paddy weeds resistant to sulfonylurea herbicides are expected to be continuously increased, the regular monitoring of their occurrence and efficient control methods should be considered in future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.105-117
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• 1972

This experiment has been made to study the relationship between several characters affecting the field lodging and to establish some useful standards for selection of lodging resistant varieties and to classify the degree of lodging resistance in wheat and barley varieties of different sources. The experiment was carried at the Crop Experiment Station, Suwon in 1968. The results obtained are summarized as followings. a. The lodging index modified with bending moment of culm at breaking seemed to be the most useful character in checking the lodging resistance. Highly significant positive correlation (Barley; r=0.40-0.67, Wheat; r=0.46-0.68) was obtained between the lodging index and actual field lodging. b. Between two essential components expressing bending stiffness of the culm, the bending moment at breaking and secondary moment of inertia, a highly significant positive correlation (Barley; r=0.59, wheat; r=0.46-0.53) was observed. c. The bending stiffness of culm got stronger as the dry weight per unit culm, which express the quantity of accumulated dry matters in culm, increased. The correlation coefficient between those two factors was 0.35 to 0.40 in barley and 0.33 to 0.76 in wheat respectively. d. In both wheat and barley, highly significant negative correlation between lodging index and the other factors such as dry weight per unit culm (Barley; r=-0. 51 to -0.70, Wheat; r=-0.65 to -0.83) and bending moment of culm at breaking (Barley; r=-0.29 to -0.69, Wheat: r=-0.54 to -0.89) were observed. Particulary, weight of culm at breaking, secondary moment of inertia and section modulus showed significant negative correlation with lodging index in wheat. e. Outside diameter of culm expressed more intimate relationship with physical characteristics of culm than inside diameter and also showed highly significant correlation with weight of culm at breaking (Barley; r=0.42-0.56, Wheat; r=0.39-0.44) and with bending moment of culm at breaking (Barley; r=0.40-0.41, Wheat; r=0.38-0.49) and with secondary moment of inertia (Barley; r=0.56-0.57, Wheat; r=0.28-0.98) and with section modulus (Wheat; r=0.22-0.96). Between the thickness of culm and physical characteristics of culm also showed the positive correlation. f. There was positive correlation between the culm length and actual field lodging in several groups of variety among the varieties tested. But the culm length seemed to undesirable as a selection measure for the selection of the lodging resistant variety considering the stiffness of culm. g. In classification of lodging resistance for the varieties tested, many Korean barley varieties expressed excellent lodging resistant than wheat, but most of the wheat and barley varieties from Japan considered quite resistant to lodging. h. In selection of lodging resistant varieties, lodging index lower than 1.67 in barley and 1. 76 in wheat considered highly resistant to actual field lodging.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.70-83
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• 2004

The safety diagnosis of cultural assets is Primarily focused on its non-destructiveness. Research on the nondestructive diagnosis and conservation of masonry cultural heritage is the key which is considered by technologic kernel. Geophyscial Prospecting as nondestructive diagnostic technology plays an important role in the characterization of the foundation of stone pagodas. It is natural that understanding of shallow subsurface condition beneath them is essential for their structural safety diagnosis. As an example, the nondestructive geophysical methods were applied to two three-story stone pagodas, Seokgatap (height 10.8 m, width 4.4 m, weight 82.3 ton) and Dabotap (height 10.4 m, width 7.4 m, weight 123.2 ton) which were built in 791 at Bulkuksa temple. An earlier archaeological investigation shows that stone pagodas have experienced severe weathering process and are slightly leaning, which will threaten their stability At the base part of Dabotap, an offset of the stone alignment is also observed. Direct measurements of ultrasonic velocities was introduced for the mechanical properties of the stone The velocity ranges of ultrasonic waves for Dabotap and Seokgatap are 1217${\~}$4403 m/s and 584${\~}$5845 m/s, respectively, and the estimated averages of the uniaxial compressive strength are 463 kg/$cm^2$ and 409 kg/$cm^2$, respectively. Site characteristics, around the pagodas are determined by the measurement of multiple properties such as seismic velocity, resistivity, image of ground-penetrating radar, On the basis of the higher velocity structure, the site of Seokgatap appears to have solider stability than the Seokgatap site. Near the pagodas, higher(up to 2200 $\Omega$m) resistivity is present whereas their outskirts have as low as 200 $\Omega$m. By the combined results of each geophyscial methods, the subsurface boundaries of two stone pagodas are revealed. The Dabotap site is in the form of an octagon having 6-m-long side with the depth of ${\~}$4 m, whereas the Seokgatap site is the 8 ${\times}$ 10 m rectangle with the depth of 3 m. These subsurface structures appear to reflect the original foundations constructed against the stone load of ${\~}8 ton/m^2$. At the subsurface beneath the northeast of each pagoda, low seismic velocity as well as low resistivity is prominent. It is interpreted to represent the weak underground condition which Is the possible cause of the slightly leaning pagodas toward the NNW.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.699-708
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• 2009

Recently as the interest in the development of domestic ore deposits has increased, we can easily find some studies on exploration geophysics-based ore-deposit survey in literature. Based on the fact that mineralized zone are generally more conductive than surrounding media, electrical resistivity survey among several geophysical surveys has been applied to investigate metallic ore deposits. Most of them are grounded on 2-D survey. However, 2-D inversion may lead to some misinterpretation for 3-D geological structures. In this study, we investigate the feasibility of the 3-D electrical resistivity survey to 3-D vein-type ore deposits. We first simulate 2-D dipole-dipole survey data for survey lines normal to the strike and 3-D pole-pole survey data, and then perform 3-D inversion. For 3-D ore-body structures, we assume a width-varying dyke, a wedge-shaped, and a fault model. The 3-D inversion results are compared to 2-D inversion results. By comparing 3-D inversion results for 2-D dipole-dipole survey data to 3-D inversion results for 3-D pole-pole survey data, we could note that the 2-D dipole-dipole survey data yield better inversion results than the 3-D pole-pole data, which is due to the main characteristic of the pole-pole array. From these results, we are convinced that if we have certain information on the direction of the strike, it would be desirable to apply 2-D dipole-diple survey for the survey lines normal to the strike. However, in most cases, we do not have any information on the direction of the strike, because we already developed the ore deposit with the outcrops and the remaining ore deposits are buried under the surface. In that case, performing 3-D pole-pole electrical resistivity survey would be a reasonable choice to obtain more accurate interpretation on ore body structure in spite of low resolution of pole-pole array.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.99-108
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• 2008

To extend our detailed knowledge for the Hwasan caldera, we carried out magnetotelluric (MT) survey, which is pretty sensitive to electrical property variation in both horizontal and vertical direction of subsurface, across the Hwasan caldera with the direction of EW. The 2-D inversion results of observed MT data lead to following conclusions. Firstly, the depth of the basin basement inferred by the MT inversion results matches well with that suggested by previous potential studies, but the basement resistivity seems fairly low when compared to that of general case. This feature might be related with the large-scaled, highly conductive layer beneath the Euisung Sub-basin suggested by the previous MT study. Secondly, the high resistivity zones reaching to 4000 $\Omega{\cdot}m$ are imaged around two external ring fault boundaries. These zones are thought of as the response of the rhyolitic dykes intruding along the ring fault, and in the previous gravity data correspond to relatively high density anomalies. Thirdly, low resistivity zone reaching to 200 $\Omega{\cdot}m$ is detected around a depth of 1km beneath the central part of the caldera, which has not been yet reported in korean geophysical literatures. If we take account of the evolution model of the Hwasan caldera, this zone is regarded as the past sedimentary layer that subsided during the period of forming external ring fault system. In addition, the relatively low density anomaly observed in the central part of the caldera may be attributed to this sedimentary layer.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.429-436
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• 2005

As Sclerotinia sclerotiorum causing cucumber sclerotinia rot was the fastest in the mycelial growth at $25^{\circ}C$, its pathogenicity was strong at the same temperature among several temperatures. All the isolates of Sclerotinia sclerotiorum showed a strong pathogenicity against cucumber fruits, which was confirmed by a disk assay and a wound assay. A wound assay was superior to a disk assay to develop the assay system for assessing the fungicidal activity of several fungicides against Sclerotinia sclerotiorum. In a disk assay, it was very difficult to assess the fungicidal activity, because the pathogenicity of isolates used in the experiment was very strong. At 500 and $3.0{\mu}g/mL$, the activity of dichloflouanid and the mixture of carbendazim and diethofencarb against cucumber sclerotinia rot was 14.3 and 42.3%, respectively, by using a disk assay. However, at same concentration two fungicides showed the high controlling activity as 100 and 92.5%, through a wound assay in a laboratory. Also, the activity of two fungicides was good against cucumber sclerotinia rot in the greenhouse where cucumber plants were cultivated in the field, showing the control value as 91.1 and 82.9% at 100 and $825{\mu}g/mL$, respectively. All the isolates of Sclerotinia sclerotiorum from cucumber fruits sampled in the polyvinyl house were subjected to monitoring for the resistance to 7 fungicides. The $EC_{50}$ value of 7 fungicides was as follows: fenhexamid; $0.13{\mu}g/mL$, procymidon and iprodione; 0.18 and $0.24{\mu}g/mL$, carbendazim and the mixture of carbendazim and diethofencarb; 0.13과 $0.05{\mu}g/mL$, iminoctadine and dichlofluanid; 1.94 and $8.95{\mu}g/mL$. Ultimately it was not found that resistant isolates of Sclerotinia sclerotiorum were appeared in the field.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.217-229
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• 2000

Adsorption equilibrium experiments for the phenol on granular activated carbon(16~25 mesh) and powder activated carbon(325 mesh) were carried out at $25{\pm}1^{\circ}C$ and the results were expressed with Freundlich isotherm. Adsorption rate experiments were executed in batch adsorption system under the condition that can be neglecting mass transfer resistance at the external surface of the particle. The results were analysed with the Miller's method to evaluate the linear driving force(LDF) adsorption rate constant. Fixed bed adsorption experiments were performed by adopting different flow rates in the activated carbon-phenol system at $25{\pm}1^{\circ}C$. The theoretical breakthrough curves were estimated with the simple constant pattern solution. The adsorption rate constant of LDF model was not a fixed value but variable with adsorption amount. The experimental results were better agreed with the estimation of breakthrough curve using the variable adsorption rate constant than the results estimated using the average fixed adsorption rate constant.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.437-448
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• 2013

Hemipteran bugs, which were previously considered as secondary pests, have currently become important pests of numerous crops. Among them, Riptortus pedestris (Fabricius) is a major species that occurs in Korea, Japan, China, and South Asian countries. Riptortus pedestris infests leguminous crops like soybean, vetches, and red clover; fruit trees like persimmon and yuju; and grains like barley, foxtail millet, broomcorn, and sorghum. Riptortus pedestris causes the greatest damage to soybean, as it is the most suitable host for the bug. Feeding damage during pod formation significantly reduces the yield of soybean. Currently, 17 insecticides, including diazinon and etofenprox, are registered for the control of hemipteran bugs in Korea, and growers apply insecticides two to three times on a regular basis. Aggregation pheromone traps are widely used as a monitoring tool and partial control measure. The aggregation pheromone of R. pedestris attracts conspecific adults and nymphs and is used for food exploitation rather than sexual attraction. In addition, the pheromone serves as a kairomone for egg parasitoids such as Gryon japonicum (Ashmead) and Ooencyrtus nezarae Ishii. As a new method of pest management, nonviable host eggs were included in the pheromone trap to catch R. pedestris and propagate parasitoids. As a part of cultural practices, resistant soybean varieties with specific color and size of pod and control of flowering time through the alteration of planting date can be used. For the effective management of R. pedestris in the near future, development of cultural practices that can support natural control factors and the use of multiple control tactics are needed.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.125-132
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• 2006

Recently, surface finishing and protection materials were developed to restore performance of the deteriorated concrete and inhibiting corrosion of the reinforcing-bar. For this purpose, surface protection agent as well as coatings are used. Coatings have the advantage of low Permeability of $CO_2,\;SO_2$ and water. However, for coatings such as epoxy, urethane and acryl, long-term adhesive strength is reduced and the formed membrane of those is blistered by various causes. Also when organic coatings are applied to the wet surface of concrete, those have a problem with adhesion. On the other hand, surface protection agent penetrates into pore structure in concrete through capillary and cm make a dense micro structure in concrete as a result of filling effect. Furthermore, the chemical reaction between silicate from surface protection agent and cement hydrates can also make a additional hydration product which is ideally compatible with concrete body. The aim of this study is to examine the effect of penetrative surface protection agent(SPA) by evaluating several concrete durability characteristics. The results show that the concrete penetrated surface protection agent exhibited higher durability characteristics for instance, carbonation velocity coefficient, resistance to chemical attack and chloride ion penetration than the plain concrete. These results due to formation of a discontinuous macro-pore system which inhibits deterioration factors of concrete by changed the pore structure(porosity and pore size distributions) of the concrete penetrated surface protection agent.