• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.77-83
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• 2014

The vessel of integral reactor contains its major primary components such as the fuel and core, pumps, steam generators, and a pressurizer, so its size is proportional to the required space for the installation of each component. The steam generators take up the largest volume of internal space of reactor vessel and their volumes is substantial for the overall size of reactor vessel. Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall cost for the components and related facilities. A printed circuit heat exchanger is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. The overall heat transfer area and pressure drops are evaluated for the steam generator based on the concept of the printed circuit heat exchanger in this study. As the printed circuit heat exchanger is known to have much larger heat transfer area density per unit volume, we can expect significantly reduced steam generator compared to former shell and tube type of steam generator. For the introduction of new steam generator, two design requirements are considered: flow area ratio between primary and secondary flow paths, and secondary side parallel channel flow oscillation. The results show that the overall volume of the steam generator can be significantly reduced with printed circuit type of steam generator.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.73-77
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• 2005

Nickel is the one of potent environmental, the occupational pollutants and the classified human carcinogens. It is a serious hazard to human health, when the metal exposure. To prevent human diseases from the heavy metals, it is seemingly important that understanding of how nickel exerts their toxicity and carcinogenic effect at a molecular and a genomic level. The process of nickel absorption has been demonstrated as phagocytosis, iron channel and diffusion. Uptaked nickel has been suggested to induce carcinogenesis via two pathways, a direct DNA damaging pathway and an indirect DNA damaging pathway. The former was originated from the ability of metal to generate Reactive Oxygen Species (ROS) and the reactive intermediates to interact with DNA directly. Ni-generated ROS or Nickel itself, interacts with DNAs and histones to cause DNA damage and chromosomal abnormality. The latter was originated from an indirect DNA damage via inhibition of DNA repair, or condensation and methylation of DNA. Cells have ability to protect from the genotoxic stresses by changing gene expression. Microarray analysis of the cells treated with nickel or nickel compounds, show the specific altered gene expression profile. For example, HIF-I (Hypoxia-Inducible Factor I) and p53 were well known as transcription factors, which are upregulated in response to stress and activated by both soluble and insoluble nickel compounds. The induction of these important transcription factors exert potent selective pressure and leading to cell transformation. Genes of metallothionein and family of heat shock proteins which have been known to play role in protection and damage control, were also induced by nickel treatment. These gene expressions may give us a clue to understand of the carcinogenesis mechanism of nickel. Further discussions on molecular and genomic, are need in order to understand the specific mechanism of nickel toxicity and carcinogenicity.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.27-33
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• 2008

In this paper, we propose a cognitive beamforming scheme for coexistence of CR (Cognitive Radio) and IR (Incumbent Radio) systems. In order to maintain the priority of the IR in spectrum utilization the proposed cognitive beamforming scheme needs to have the CR not cause any interference to the IR systems occupying the same frequency band at the same time. In addition the proposed scheme has to provide maximum channel gain to the CRU (CR User) in a boundary of satisfying the former criterion. For this purpose, the proposed scheme does not cause any interference to the IRU (IR User), while the CRU is served without additional radio resource consumption. From simulation, we confirmed that when using the proposed scheme the CRU does not interfere with the IRU and there is little bit error rate performance degradation of the CRU as compared to that of the ideal beamforming system, which does not consider the IR priority.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.13.1-13.1
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• 2009

Transparent electronics has attracted many interests, for it can open new applications for consumer electronics, transportation, business, and military. Among them, display backplane, thin film transistor (TFT) array would be the most attractive application. Many researchers have been investigating oxide semiconductors for transparent channel material of TFT since the report for transparent amorphous oxide semiconductor (TAOS) TFT by Hosono group and ZnO TFT by Wager group. Especially, oxide TFTs have been intensively investigated during a couple of years since the first demonstration of ZnO-TFT driving AM-OLED. Many papers regarding the fabrication and performance of oxide TFTs, and active matrix display driven by oxide TFTs have been reported. Now lots of people have confidence in the competitiveness of oxide TFTs for the backplane of AM-Display. Especially, high mobility, uniformity, fairly good stability, and low cost process make oxide TFTs applied even to a large size AM-OLED. Last year, Samsung mobile display, former SID, reported 12" AM-OLED driven by IZGO-TFT and it seems that the remained issue for the mass production is the bias temperature stability. Here, we will introduce the application of oxide TFT and important issue for oxide TFT to be used for the direct printing.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.202-216
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• 1999

The deep foundation is frequently used for the infrastructures. Since the quality control of the cast-in-place concrete foundations such as CIP piles and slurry walls is not so easy as that of the ready made PC(prestressed concrete) piles, it is necessary to get the information on the integrity of the concrete of the foundation. The depth estimation of foundations whose depths are unknown is also very important in repair and reinforcement works or in safety inspection and assessment to the big structures. The cross-hole sonic logging(CSL) system and the single channel reflection seismic measurement system were developed to test the integrity of pile. The former is well applied to CIP structures, while the later to all kinds of piles with less accurate result compared to that of CSL. To estimate the depth of the deep foundations, parallel seismics, borehole RADAR, and borehole magnetics can be used.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.55-67
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• 1995

The error rate equations of MPSK and DS/MPSK radio signals transmitted through the m-distributed fading channel in Gaussian noise and tone interference environments have been derived. Using the derived equations, the error rate performance is evaluated and shown as functions of carrier-to-noise ratio, carrier-to-interference ratio, processing gain, fading index and the number of diversity branches. The derivation has been done for two cases. The first case assumes that only the signal is undergoing the influence of fading, and the second case assumes that both signal and interference are undergoing the influence of fading simultaneously. From the obtained results, we have known that the error performance of MPSK signal is improved by using diversity technique and direct sequence spread spectrum technique even in a fading environment. Also comparing the error rate performance of two cases, the latter is worse than the former.

• Asia-Pacific Journal of Business
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• v.11 no.2
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• pp.61-79
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• 2020

Purpose - This article empirically investigated the effects of the socio-political factor of censorship preconditioning, and organizational support, mediating performance expectancy of public sector officials' behavioural intention to utilise social media in a post-communist country, Mongolia. Design/methodology/approach - This study collected 212 survey data from public sector organisations in Mongolia. Using the Partial Least Squire (PLS) method, this study analyzed the proposal model grounded on the UTAUT model. Findings - There are still communist footprints in the form of censorship, which remained as a negative precondition factor, and this has an indirect negative influence, and organisational support mediates to enhance performance expectancy. Effort expectancy and social influence factors have direct positive influence on the use of social media systems in the government domain of Mongolia Research implications or Originality - This study empirically investigated the model of public employees' intention to examine the post-communist countries' cultural, social, economic, and political systems, government organisational environment of the former communist sphere. The cultural factors, censorship and organisational support, to the existing IT adoption UTAUT model were also identified to test the situation of a post-communist country, Mongolia. This study contributes to the new theoretical involvement with social media by testing a new social media-based third-party intercommunication channel, including intent to use in the public service for post-communist countries. This study practically provides the guidelines to promote social media usage for public sector in the post-communist situation.

• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.223-231
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• 2023

An integrated-optical biochemical sensor structure that can perform homogeneous and surface sensing using a 2×2 balanced-bridge Mach-Zehnder interference structure based on the optimized SOI slot optical waveguide was described, and its performance and characteristics were evaluated. Equations for the two output optical powers were derived and examined using the transfer matrices of a 3-dB coupler and phase shifter (channel waveguide). The length of the 3-dB coupler was determined such that the two output optical powers were same using these formulas. In homogeneous sensing, the effect of the refractive index of an analyte in the range of 1.33-1.36 on the two output optical power distributions was numerically derived, and the sensitivity was calculated based on each output and the difference between the two outputs, the former and the latter being 7.5796-19.0305 [au/RIU] and 15.2601-38.1351 [au/RIU], respectively. In the case of surface sensing, the sensitivity range of the refractive index of 1.337 based on each of the two outputs was calculated as -2.2490--3.5854 [au/RIU] and 1.2194-3.8012 [au/RIU], and the sensitivity range of 4.8048-7.0694 [au/RIU] was confirmed based on the difference between the two outputs.

• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.153-177
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• 2013

To get the various data on geological information, distributional ratios and characteristics of constituent rocks with geologic ages and rock types were obtained by ArcGIS 10.1 program, digital geologic and geomorphic maps of 1:250,000 scale in Jeonnam and Gwangju areas. In the Jeonnam area, geologic ages can be largely divided into 7, in which their distribution ratios show decreasing trends in the order of Cretaceous, Precambrian, Jurassic, Quaternary, Age-unknown, Carbonifeorus-Triassic and Triassic, and the former fours make the most prevailing ratios of 94.80%. Rock types in the area can be assorted into 57 ones, in which major 7 ones occupy the dominant ratio of 71.68%. Among them, Kav (acidic volcanics+rhyolite and rhyolitic tuff) show much more distribution ratios than the others. It shows more aspects distributed in north, west, middle, east and south parts, especially in Sinan-Mogpo-Yeongam of west and Haenam of south parts in the area, respectively. On the other hand, geological ages in Gwangju area can be largely divided into 5, in which their distribution ratios show decreasing trends in the order of Jurassic, Quaternary, Cretaceous, Precambrian and Age-unknown, and the former fours occupy almost the whole ratio of 98.95%. Rock types in the area are 12 ones, in which major four ones make up the dominant value of 91.30%. Among them, Jurassic granites of the most dominant value are mostly occupied in the southwest-northeast part of the area. Next dominative Quaternary alluvium is mostly developed along the Yeongsan river, the Hwangryong river and their channel junction. And Yongdu and Donggye plains are well developed around the Yeongsan riverline, and channel junction of the Yeongsan and Hwangryong rivers in the area, respectively.

• The Korean Journal of Quaternary Research
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• v.13 no.1
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• pp.67-78
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• 1999

In present, the terminal area of the Nagdong River Delta consists of micro-depositional landforms with sand barrier islands, sand bars and tidal flats which are arranged parallel to the present shoreline, and have rapidly shifted toward sea during last 100 years due to human activities such as construction of estuary dam, industrial complex and residential area. To clarify the landform changes of the area, the author traced the morphologic change pattern based on interpretation of air-photos, topographic maps and old Korean traditional map, and the results are as follows ; Based on the Daedongyeojido, one of the old Korean map, published in 1861, the area including upper part of the delta was underlying by sea level except two larger sand barriers, which means the Nagdong River Delta was not completely formed as the present outline of morphology by 1860s. According to the topographic map(1 :50,000) of 1916, the delta resembled to the present morphology pattern was exposed in 1916, and at this time the area was mainly composed of one sand barrier island, four sand bars and tidal flats, which had slowly elongated southwards before construction of the Nagdong River Estuary Dam in 1987. But after 1987, the area has been rapidly and drastically shifted southwards in arrange with one chain of sand barrier islands (Elsugdo -Myeonghodo-Sinhodo ) and four chains of sand bars (first chain ; Jinwoodo -Daemadeung-Maenggeummeorideung, second chain : Jangjado-Baeghabdeung, third chain ; Saedeung-Namusitdeung, fourth : Doyodeung-Dadaedeung) parallel to shoreline. This rapid landform change of the area is now occurring, and is seemed to ascribed firstly, to the construction of the Nagdong River Estuary Dam on Elsugdo in 1987, the Sinho Industrial Complex on Sinhodo and Myeongji Residential Area on Myeonghodo in 1992, secondly, to artificial alteration of drainage channel and consequential breakdown of former energy system between riverflow and tidal-and wave-energy. From these facts, it is inferred that the landform change pattern of the area will continue until a new equilibrium between the factor available to this energy system is accomplished.