• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.53-66
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• 2023

In this study, the results of the elasto-plastic beam analysis, finite element analysis and optimization design of the steel pipe sheet pile applied as an earth retaining wall under the deep excavation were presented. Through this study, it was found that the high-strength and sea resistant steel pipe has high allowable stress, excellent structural properties, favorable corrosion, and high utilization as an earth retaining wall, and the C-Y type joint has significantly improved the tensile strength and stiffness compared to the traditional P-P type. In addition, it was investigated that even if the leak or defect of the wall occurs during construction, it has the advantage of being able to be repaired reliably through welding and overlapping. In the case of steel pipe wall, they were evaluated as the best in views of the deep excavation due to the large allowable bending stress and deformation flexibility for the same horizontal displacement than CIP or slurry wall. Elasto-plastic and finite element analysis were conducted in consideration of ground excavation under large-scale earth pressure (uneven pressure), and the results were compared with each other. Quantitative maximum value were found to be similar between the two methods for each item, such as excavation behavior, wall displacement, or member force, and both analysis method were found to be applicable in design for steel pipe sheet pile wall. Finally, it was found that economical design was possible when determining the thinnest filling method with concrete rather than the thickest hollow shape in the same diameter, and the depth (the embedded length through normality evaluation) without rapidly change in displacement and member force.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.429-436
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• 2023

Traditional Chinese music has a deep indigenous color and has its own unique way of thinking and characteristics. A consensus has already been formed that linear thinking is a major feature of traditional Chinese music, and it has been implemented in both traditional multi-tone and single-tone music. It is mainly expressed in the form of single-tone music or single-tone music. This linear thought of traditional Chinese music is formed by influencing factors in various fields. For example, it is related to national culture, geographical and natural environment, religious and philosophical background, traditional Chinese notation, individual characteristics of traditional musical instruments, Yulje, composition, and transmission methods. This thinking is different from Western classical music that pursues three-dimensional thinking, and Western music emphasizes the harmony of harmony, harmony of tone and texture, logic and identity of structure, and emphasizes the aspect of space. However, traditional Chinese music emphasizes the horizontal development of melody, the fluency of ancestors, and the continuity of structure. We aims to analyze the causes of linear thinking of traditional Chinese music so that it can be more useful in educational aspects and promote the succession and development of traditional music by transferring knowledge of ethnic music.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.294-302
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• 2023

Ni-Mn-Zn ferrite, Ni_0.5-xMn_xZn_0.5Fe₂O₄ (0 ≤ x ≤ 0.5), was synthesized using the sol-gel method to investigate the crystal structure, microstructure, magnetic properties, high-frequency characteristics, and electromagnetic (EM) wave absorption characteristics as a function of Mn substitution. As the Mn content increased, a continuous decrease in saturation magnetization (M_S) was observed with little change in coercivity (H_C). Samples for each composition (x) exhibited strong EM wave absorption performance with first and second strong EM wave absorption regions satisfying minimum reflection loss, RL_min < -40 dB in the 1.5~2.5, 6~11 GHz range, respectively. The EM wave absorption in Ni-Mn-Zn ferrite depends on magnetic loss, and adjusting µ' and µ'' spectra by Mn substitution or H field allows control of the EM wave absorption frequency.

• Journal of the Korean GEO-environmental Society
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• v.25 no.3
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• pp.5-11
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• 2024

Promising geological structures for carbon dioxide capture and subsurface storage include aquifers, depleted reservoirs, and gas fields. Among these, aquifers are gaining attention due to their potential for storing significant amounts of carbon dioxide compared to other geological structures. Therefore, there is a growing interest in enhancing carbon dioxide storage efficiency by understanding the characteristics of aquifers and developing technologies tailored to their properties. In this study, the storage efficiency of carbon dioxide injection following surfactant pre-injection into porous micro-models was evaluated. The results indicate that as the concentration of the surfactant solution injected prior to carbon dioxide injection increases, storage efficiency improves. Conversely, lower concentrations require more surfactant injection to enhance storage efficiency. Furthermore, under identical surfactant concentration conditions, the storage efficiency from surfactant pre-injection prior to supercritical carbon dioxide injection is approximately 30% lower compared to surfactant-co-solvent substitution as observed in previous studies. However, under the maximum concentration conditions investigated in this study, similar storage efficiencies to those of previous studies were achieved. These findings are expected to guide concentration determinations for surfactant application aimed at enhancing carbon dioxide storage efficiency in aquifers in future studies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.10-18
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• 2024

Vehicle loading is one of the main causes of bridge deterioration. Although WiM (Weigh in Motion) can be used to measure vehicle loading on a bridge, it has disadvantage of high installation and maintenance cost due to its contactness. In this study, a non-contact method is proposed to estimate the vehicle loading history of bridges using deep learning and CCTV images. The proposed method recognizes the vehicle type using an object detection deep learning model and estimates the vehicle loading based on the load-based vehicle type classification table developed using the weights of empty vehicles of major domestic vehicle models. Faster R-CNN, an object detection deep learning model, was trained using vehicle images classified by the classification table. The performance of the model is verified using images of CCTVs on actual bridges. Finally, the vehicle loading history of an actual bridge was obtained for a specific time by continuously estimating the vehicle loadings on the bridge using the proposed method.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.9-15
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• 1997

The study area is located in the Central Bransfield Basin, Antarctica. To analyze the morphology of seafloor, structure of basement, and seismic stratigraphy of the sedimentary layers, we have acquired, processed, and interpreted the multi-channel seismic data. The northwest-southeastern back-arc extension dramatically changes seafloor morphology, volcanic and fault distribution, and basin structure along the spreading ridges. The northern continental shelf shows a narrow, steep topography. In contrast, the continental shelf or slope in the south, which is connected to the Antarctic Peninsula, has a gentle gradient. Volcanic activities resulted in the formation of large volcanos and basement highs near the spreading center, and small-scale volcanic diapirs on the shelf. A very long, continuous normal fault characterizes the northern shelf, whereas several basinward synthetic faults probably detach into the master fault in the south. Four transfer faults, the northwest-southeastern deep-parallel structures, controlled the complex distributions of the volcanos, normal faults, depocenters, and possibly hydrocarbon provinces in the study area. They have also deformed the basement structure and depositional pattern. Even though the Bransfield Basin was believed to be formed in the Late Cenozoic (about 4 Ma), the hydrocarbon potential may be very high due to thick sediment accumulation, high organic contents, high heat flow resulted from the active tectonics, and adequate traps.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1288-1298
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• 2002

To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.45-47
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• 2002

반도체 소자의 고집적화 및 고속화가 요구됨에 따라 MOSFET 구조의 게이트 절연막으로 사용되고 있는 SiO₂ 박막의 두께를 감소시키려는 노력이 이루어지고 있다. 0.1㎛ 이하의 소자를 위해서는 15Å 이하의 두께를 갖는 SiO₂가 요구된다. 하지만 두께감소는 절연체의 두께와 지수적인 관계가 있는 누설전류를 증가시킨다[1-3]. 따라서 같은 게이트 개패시턴스를 유지하면서 누설전류를 감소시키기 위해서는 높은 유전상수를 갖는 두꺼운 박막이 요구되는 것이다. 그러므로 약 25정도의 높은 유전상수를 갖고 5.2～7.8 eV 정도의 비교적 높은 bandgap을 갖으며, 실리콘과 열역학적으로 안정한 물질로 알려진 HfO2[4-5]가 최근 큰 관심을 끌고 있다. 본 연구에서는 HfO₂ 박막을 실제 소자에 적용하기 위하여 전극 및 열처리에 따른 HfO₂ 박막의 미세구조 및 전기적 특성에 관한 연구를 수행하였다. 이를 위해, HfO₂ 박막을 reactive DC magnetron sputtering 방법으로 증착하고, XRD, TEM, XPS를 사용하여 ZrO₂ 박막의 미세구조를 관찰하였으며, MOS 캐패시터 구조의 C-V 및 I-V 특성을 측정하여 HfO₂ 박막의 전기적 특성을 관찰하였다. HfO₂ 타겟을 스퍼터링하면 Ar 스퍼터링에 의해 에너지를 가진 산소가 기판에 스퍼터링되어 Si 기판과 반응하기 때문에 HfO₂ 박막 형성과 더불어 Si 기판이 산화된다[6]. 그래서 HfO₂같은 금속 산화물 타겟 대신에 순수 금속인 Hf 타겟을 사용하고 반응성 기체로 O₂를 유입시켜 타겟이나 시편위에서 high-k 산화물을 만들면 SiO/sub X/ 계면층을 제어할 수 있다. 이때 저유전율을 갖는 계면층은 증착과 열처리 과정에서 형성되고 특히 500℃ 이상에서 high-k/Si를 열처리하면 계면 SiO₂층은 증가하는 데, 이것은 산소가 HfO₂의 high-k 박막층을 뚫고 확산하여 Si 기판을 급속히 산화시키기 때문이다. 본 방법은 증착에 앞서 Si 표면을 희석된 HF를 이용해 자연 산화막과 오염원을 제거한 후 Hf 금속층과 HfO₂ 박막을 직류 스퍼터링으로 증착하였다. 우선 Hf 긍속층이 Ar 가스 만의 분위기에서 증착되고 난 후 공기중에 노출되지 않고 연속으로 Ar/O₂ 가스 혼합 분위기에서 반응 스퍼터링 방법으로 HfO₂를 형성하였다. 일반적으로 Si 기판의 표면 위에 자연적으로 생기는 비정질 자연 산화막의 두께는 10～15Å이다. 그러나 Hf을 증착한 후 단면 TEM으로 HfO₂/Si 계면을 관찰하면 자연 산화막이 Hf 환원으로 제거되기 때문에 비정질 SiO₂ 층은 관찰되지 않았다. 본 실험에서는 HfO2의 두께를 고정하고 Hf층의 두께를 변수로 한 게이트 stack의 물리적 특성을 살펴보았다. 선증착되는 Hf 금속층을 0, 10, 25Å의 두께 (TEM 기준으로 한 실제 물리적 두께) 로 증착시키고 미세구조를 관찰하였다. Fig. 1(a)에서 볼 수 있듯이 Hf 금속층의 두께가 0Å일때 13Å의 HfO₂를 반응성 스퍼터링 방법으로 증착하면 HfO₂와 Si 기판 사이에는 25Å의 계면층이 생기며, 이것은 Ar/O₂의 혼합 분위기에서의 스퍼터링으로 인한 Si-rich 산화막 또는 SiO₂ 박막일 것이다. Hf 금속층의 두께를 증가시키면 계면층의 성장은 억제되는데 25Å의 Hf 금속을 증착시키면 HfO₂ 계면층은 10Å미만으로 관찰된다. 그러므로 Hf 금속층이 충분히 얇으면 플라즈마내 산소 라디칼, 이온, 그리고 분자가 HfO₂ 층을 뚫고 Si 기판으로 확산되어 SiO₂의 계면층을 성장시키고 Hf 금속층이 두꺼우면 SiO/sub X/ 계면층을 환원시키면서 Si 기판으로의 산소의 확산은 막기 때문에 계면층의 성장은 억제된다. 따라서 HfO₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의 두께보다 높은 CET값을 보이고 Hf 금속층의 두께를 증가시키면 CET는 급격하게 감소한다. 그러므로 HfO₂/Hf 박막의 유효 유전율은 단순 반응성 스퍼터링에 의해 형성된 HfO₂ 박막의 유전율보다 크다. Fig. 2에서 볼 수 있듯이 Hf 금속층이 너무 얇으면 계면층의 두께가 두꺼워 지고 Hf 금속층이 두꺼우면 HfO₂층의 물리적 두께가 두꺼워지므로 CET나 EOT 곡선은 U자 형태를 그린다. Fig. 3에서 Hf 10초 (THf=25Å) 에서 정전 용량이 최대가 되고 CET가 20Å 이상일 때는 high-k 두께를 제어해야 하지만 20Å 미만의 두께를 유지하려면 계면층의 두께를 제어해야 한다.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.87-106
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• 2005

In order to evaluate the mechanism of transmission as well as processing of sensory information originating from low-threshold mechanoreceptor in oral and maxillofacial region at primary synaptic region of trigeminal nervous system, vibrissa afferent fibers of adult cat were labeled with intra-axonal HRP injection. Serial sections containing labeled boutons were obtained from the piece of trigeminal interpolar nucleus. Under electron microscope, total 30 labeled boutons were observed, and ultrastructural characteristics, frequency of occurence, synaptic organizations of vibrissa afferent terminals were analysed. The results were as follows: 1. Labeled boutons contained clear, spherical synaptic vesicles with diameter of 45$\sim$55nm. They formed asymmetrical synapse with dendrites showing definite postsynaptic density, larger synaptic cleft, multiple synaptic structures at various regions. With unlabeled axon terminals(p-ending) containing polymorphic synaptic vesicles, they formed symmetrical synapse showing indefinite postsynaptic density and narrower synaptic area. 2. Each labeled bouton formed 1 to 15 synapses, the average of 4.77$\pm$3.37 contacts per labeled bouton, with adjacent neuronal profiles. Relatively complex synaptic organization, which formed synapses with more than 5 neuronal profiles, was observed in a large number(46.7%, n=14) of labeled boutons. 3. Axo-somatic synapse was not observed. The number of axo-dendritic synapse was 1.83$\pm$1.37 per labeled bouton. Majority(85.0%) of axo-dendritic synapses were formed with dendritic shafts, nonprimary dendrites(n=47, 1.57$\pm$1.38/1 bouton), however, synapses formed with primary dendrites(n=6, 0.20$\pm$0.41/1 bouton) or dendritic spines(n=2, 0.07$\pm$0.25/1 bouton) were rare. 4. 76.7%(n=23) of labeled boutons formed axo-axonic synapse (2.93$\pm$2.36/1 bouton) with p-endings containing pleomorphic vesicles. Synaptic triad, in which p-endings formed synapses with labeled boutons and dendrites adjacent to the labeled boutons simultaneoulsy, were also observed in 60.0%(n=18) of labeled boutons. From the above results, vibrissa afferent terminals of adult cat showed distinctive synaptic organization in the trigeminal interpolar nucleus, thus, suggests their correlation with the function of the trigeminal interpolaris nucleus, which participates in processing of complex sensory information such as two-point discrimination and motivational-affective action. Further studies on physiologic functions such as quantitative analysis on ultrastructures of afferent terminals and nerve transmitters participating in presynaptic inhibition are required.