• Economic and Environmental Geology
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• v.56 no.2
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• pp.115-123
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• 2023

We introduce a new 'image-mapping' in-situ U-Pb dating method using LA-ICP-MS, proposed by Drost et al. (2018), and show the characteristics and usability of this method through several examples of absolute age results determined by first applying it to samples from the Joseon Supergroup of the Early Paleozoic Era in Korea. Unlike the previous in-situ spot analysis, this in-situ U-Pb dating method for carbonate minerals can determine the absolute age with high reliability by applying the 'image-mapping' method of micro-sized domains based on micro-textural observation, as well as determine the absolute age of multiple geological 'events' that occurred after deposition. This was confirmed in the case of determining the syn-depositional age and the multiple post-depositional ages from carbonate minerals of the Makgol and the Daegi Formations. Therefore, if the 'image-mapping' in-situ U-Pb dating method is applied to determine the absolute age of various types of carbonate minerals that exist in various geological environments throughout the geologic era, it will be possible to secure new geological age information.

• International Journal of Concrete Structures and Materials
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• v.3 no.1
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• pp.63-69
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• 2009

This paper provides the engineer with a simple design method dealing with situations arise where in-situ reinforced concrete joints are cast between hollow core units. Using finite element method, hollow core slabs with wide in-situ RC joints under point load and line loads are analysed. In addition, some important behavioural characteristics of the floor slab subjected to line and point loads are investigated. In-situ reinforced concrete joint causes reduction of load distribution for remote units because distance to the remote units from the point of load is increased, while the portion of load distribution carried by loaded unit increases. Also, it was turned out load distribution factors for point load and line loads are almost same. Finally, we suggest a simple analytical method, which can determine load distribution factors using normalized deflections by regression analysis for design purposes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.73-83
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• 2017

This study was conducted to evaluate the chemical composition, digestibility, and energy value of 15 non-conventional feeds produced in South Korea as ruminant feeds. Three Hanwoo steers (body weight, $520{\pm}20.20kg$) fitted with a permanent rumen cannula and duodenal cannula were housed individually in tie-stall barns, followed by a 14-day adaptation period and 3-day experimental period. Chemical composition analysis, in situ nylon bag, and mobile bag technique were used as experiments. As a result of the chemical composition analysis offeeds, crude protein (CP) contentsofmalt meal, perilla meal, soy sauce cake, and soymilk residue were greater than 30%. As a result of the degradability characteristics analysis of feeds using an in situ nylon bag, rumen undegraded protein (RUP) contents of beet pulp, brewer's grain, coffee meal, malt meal, milo bran, perilla meal, ramen residue, and soymilk residue were greater than 50%. Analysis of total digestible nutrient (TDN) values of feeds using an in situ mobile bag showed that TDN values of beet pulp, brewer's grain, makgeolli residue, milo bran, perilla meal, ramen residue, rice bran, soy sauce cake, soybean curd cake, soymilk residue, and wheat bran weregreater than 50%. In summary, these non-conventional feeds have high potential value as good feed resources to replace formulated feeds or roughage. Therefore, the chemical composition, digestibility, and energy value of non-conventional feeds obtained from this study can be used as base data for the manufacture of ruminant total mixed ration (TMR) with improved feed efficiency, reduced feed costs, and reduction of environmental pollution.

• Korean Journal of Materials Research
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• v.28 no.6
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• pp.330-336
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• 2018

In this study, a membrane electrode assembly(MEA) composed of three electrodes(anode, cathode, and reference electrode) is designed to investigate the effects of methanol concentration on the overpotentials of anode and cathode in direct methanol fuel cells(DMFCs). Using the three-electrode cell, in-situ analyses of the overpotentials are carried out during direct methanol fuel cell operation. It is demonstrated that the three-electrode cell can work effectively in transient state operating condition as well as in steady-state condition, and the anode and cathode exhibit different overpotential curves depending on the concentration of methanol used as fuel. Therefore, from the real-time separation of the anode and cathode overpotentials, it is possible to more clearly prove the methanol crossover effect, and it is expected that in-situ analysis using the three-electrode cell will provide an opportunity to obtain more diverse results in the area of fuel cell research.

• Geomechanics and Engineering
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• v.9 no.1
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• pp.101-113
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• 2015

Saturated soil hydraulic conductivity is a very important soil parameter in numerous practical engineering applications, especially rainfall infiltration and slope stability problems. This parameter is difficult to measure since it is very highly sensitive to various soil conditions. There have been many analytical and empirical formulas to predict saturated soil hydraulic conductivity based on experimental data. However, there have been few studies to investigate in-situ hydraulic conductivity of weathered granite soils, which constitute the majority of soil slopes in Korea. This paper introduces an estimation method to derive saturated hydraulic conductivity of Korean weathered granite soils using in-situ experimental data which were obtained from a variety of slope areas of South Korea. A robust regression analysis was performed using different physical soil properties and an empirical solution with an $R^2$ value of 0.9193 was suggested. Besides that this research validated the proposed model by conducting in-situ saturated soil hydraulic conductivity tests in two slope areas.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.552-554
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• 2003

The development of high performance single nanoparticle ion trap (SNIT) apparatus for studying in-situ dynamics of single nanoparticles in controlled environments is described. The performance of SNIT apparatus has been evaluated for 500 nm SiO₂particles. The mass resolution of ~100 ppm and the capability of varying the charge states independently have been demonstrated.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.133-137
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• 1987

Polysiloxane SE-54 liquid phase was immobilized on the support surface as coated in thin film via in-situ cross-linking. The cross-linking between liquid molecules was initiated by dicumylperoxide. Among the supports investigated, only Chromosorb W provided the cross-linkable surface. The optimal in-situ cross-linking was achieved when Chromosorb W was coated with 5% (w/w) SE-54 and cross-linked with 1% (w/w) dicumylperoxide. The cross-linked support was useful for the trace analysis as well as for the trace enrichment.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.111-116
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• 2008

Since the hydraulic fracturing field testing method was introduced first to Korean geotechnical engineers in 1994, there have been lots of progresses in a hardware system as well as an interpretation tool. The hydrofracturing system of first generation was the pipe-line type, and it has been developed to a wire-line system at their second generation. The current up-to-date system is more compact and is able to be operated by all-in-one system. With a progress in a hardware system, the software for analyzing in-situ stress regime has also been progressed. The shut-in pressure, which is the most ambiguous parameter to be obtained from hydrofracturing pressure curves, can now be acquired automatically from the various methods. While the hardware and software for hydrofracturing tests are being developed during the last decade, the author could accumulate the field test results which can cover the almost whole area of South Korea. Currently these field data are used widely in a feasibility study or a preliminary design step for tunnel construction in Korea. Regarding the difficulties in a site selection and a test performance for the in-situ stress measurement at an off-shore area, the in-situ stress regime obtained from the field experiences in the land area can be used indirectly for the design of a sub-sea tunnel. From the hydrofracturing stress measurements, the trend of magnitude and direction of in-situ stress field was shown identically with the geological information in Korea.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.186-188
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• 2005

Because forest fire changes the direction according to the environmental elements, it is difficult to predict the direction of it. Currently, though some researchers have been studied to which predict the forest fire occurrence and the direction of it, using the remote detection technique, it is not enough and efficient. And recently because of the development of the sensor technique, a lot of In-Situ sensors are being developed. These kinds of In-Situ sensor data are used to collect the environmental elements such as temperature, humidity, and the velocity of the wind. Accordingly we need the prediction technique about the environmental elements analysis and the direction of the forest fire, using the In-Situ sensor data. In this paper, as a technique for predicting the direction of the forest fire, we propose the correlation analysis technique about In-Situ sensor data such as temperature, humidity, the velocity of the wind. The proposed technique is based on the clustering method and clusters the In-Situ sensor data. And then it analyzes the correlation of the multivariate correlations among clusters. These kinds of prediction information not only helps to predict the direction of the forest fire, but also finds the solution after predicting the environmental elements of the forest fire. Accordingly, this technique is expected to reduce the damage by the forest fire which occurs frequently these days.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.153-153
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• 2012

Endpoint detection with plasma impedance monitoring and self-plasma optical emission spectroscopy is demonstrated for dielectric layers etching processes. For in-situ detecting endpoint, optical-emission spectroscopy (OES) is used for in-situ endpoint detection for plasma etching. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. To overcome these problems, the endpoint was determined by impedance signal variation from I-V monitoring (VI probe) and self-plasma optical emission spectroscopy. In addition, modified principal component analysis was applied to enhance sensitivity for small area etching. As a result, the sensitivity of this method is increased about twice better than that of OES. From plasma impedance monitoring and self-plasma optical emission spectroscopy, properties of plasma and chamber are analyzed, and real-time endpoint detection is achieved.