• Journal of the Korean Wood Science and Technology
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• v.48 no.1
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• pp.32-40
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• 2020

While the utilization of wood as a raw material in related industries has been increasing with the population increasing, the availability of wood from natural forests has continued to decline. An alternative to this situation is the manufacture of particleboard from non-wood lignocellulose materials through the modification of sandwich particleboard (SPb) using bamboo strands as reinforcement. In this study, strandsof belangke bamboo (Gigantochloa pruriens W) and tali bamboo (Gigantochloa apus) were utilized. The non-wood particles included sugar palm fibers, cornstalk, and sugarcane bagasse. The board was made in a three-layer composition of the face, back, and core in a ratio of 1: 2: 1. The binder used was 8% isocyanate resin. The sheet was pressed at a temperature of 160℃ for 5 min under a pressure of 3.0 N/㎟. Testing included physical and mechanical properties based on the JIS A 5908 (2003) standard, while acoustic testing was based on ISO 11654 (1997) standards. The results showed that using bamboo strands as reinforcement has an effect on the mechanical and physical properties of SPb. Almost all the types of boards met the JIS A 5908 (2003) standards, with the exception of thickness swelling (TS) and internal bond (IB) parameters. Based on the thickness swelling parameter, the C-type board exhibited the best properties. Overall, the B-type board thatused a belangke bamboo strand for the surface and sugarcane bagasse as the core underwent the best treatment. Based on the acoustical parameter, boards using a tali bamboo strand for the surface and sugar palm fiber as the core (E-type board) exhibited good sound absorption properties.

• The Journal of Fisheries Business Administration
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• v.52 no.1
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• pp.1-22
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• 2021

This study aims to face common threats from the depletion of fish resources, the decline of production and employment as well as the increase of life risk in East Sea Rim countries, North Korea, South Korea, Japan and Russia due to the Chinese fishing fleets entering East Sea. The recent competition in fishing among fishing vessels and fleets of national origin operating in the East Sea has induced a significant change in the ecological landscape of the fishing fleets cluster while having influenced production and employment in the fishing industries of South Korea and Japan as well as life threat on the fishermen in North Korea. It seems that the population organizational ecological theory can be applied to this change. It can be seen as the isomorphism of the selection process over the exclusive economic zone (EEZ) to avoid the environment in which these North Korean fishing vessels are pushed against the Chinese fleet in the North Korean part of the East Sea. To resolve the fishery disputes or conflict in the common waters in East Sea, first of all, Chinese fishing fleets will be required to put international pressure so as to solve the unfairness of the illegal fishing and overfishing by the International Fishery Organization or the UN violations of the sanctions against North Korea selling fishing rights to China. Although it is not easy for South Korea to cooperate with North Korea in the short term, South Korea will be able to support the fishery infrastructure in North Korea in the mid- to the long-term to prevent the loss of innocent lives for their fishermen and to raise their incomes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.4
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• pp.561-571
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• 2019

Drilling and charging of the blast holes during NATM tunneling works take more than 30% of construction time among the whole tunneling work process. Prediction of ground condition ahead of tunnel face has been studied by several researchers by correlating percussion pressure and drilling speed during tunneling work with the ground condition and/or RMR values. However, most of the previous researches were conducted in the granite rock condition which is the most representative igneous rock in the Korean peninsula. In this study, drilling speeds in igneous rocks were analyzed and compared with those in sedimentary rocks (most dominantly composed of conglomerates, sandstones, and shales) under the similar RMR ranges; it was identified that the drilling speed is pretty much affected by rock types even in a similar RMR range. Under the similar RMR values, the drilling speed was faster in sedimentary rocks compared with that in igneous rock. Moreover, while the drilling speed was not much affected by change of the RMR values in igneous rocks, it became faster in sedimentary rocks as the RMR values got lower.

• Geomechanics and Engineering
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• v.17 no.4
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• pp.375-383
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• 2019

In underground retreating longwall coal mining, hard roof collapse is one of the most challenging safety problems for mined-out areas. Identifying precursors for hard roof collapse is of great importance for the development of warning systems related to collapse geohazards and ground control. In this case study, the Xinhe mine was chosen because it is a standard mine and the minable coal seam usually lies beneath hard strata. Real-time monitoring of hard roof collapse was performed in longwall face 5301 of the Xinhe mine using support resistance and microseismic (MS) monitoring; five hard roof collapse cases were identified. To reveal the characteristics of MS activity during hard roof collapse development and to identify its precursors, the change in MS parameters, such as MS event rate, energy release, bursting strain energy, b value and the relationships with hard roof collapse, were studied. This research indicates that some MS parameters showed irregularity before hard roof collapse. For the Xinhe coalmine, a substantial decrease in b value and a rapid increase in MS event rate were reliable hard roof collapse precursors. It is suggested that the b value has the highest predictive sensitivity, and the MS event rate has the second highest.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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• pp.100-103
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• 2019

The change in vanadium amount according to the growth direction of vanadium-doped semi-insulated (SI) SiC single crystals using high-purity SiC powder was investigated. High-purity SiC powder and a porous graphite (PG) inner crucible were placed on opposite sides of SiC seed crystals. SI SiC crystals were grown on 2 inch 6H-SiC Si-face seeds at a temperature of $2,300^{\circ}C$ and growth pressure of 10~30 mbar of argon atmosphere, using the physical vapor transport (PVT) method. The sliced SiC single crystals were polished using diamond slurry. We analyzed the polytype and quality of the SiC crystals using high-resolution X-ray diffraction (XRD) and Raman spectroscopy. The resistivity of the SI SiC crystals was analyzed using contactless resistivity mapping (COREMA) measurements.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.1
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• pp.61-69
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• 2021

Background: Inferior alveolar nerve block (IANB) using lidocaine 2% is commonly used for anesthetizing primary mandibular molars; however, this technique has the highest level of patient discomfort compared to other local anesthesia techniques. Therefore, alternative anesthesia techniques are necessary. The aim of this study was to evaluate the efficacy of a single buccal infiltration of 4% articaine with IANB using 2% lidocaine, for the bilateral extraction of primary mandibular molars. Methods: The present study was conducted on 30 patients aged between 6 and 9 years, who required the extraction of bilateral primary mandibular molars. The patients were randomly divided into two groups as follows: In the first session, Group A received IANB with lidocaine 2% and group B received infiltration with articaine 4%. In the second session, another injection method was performed on the opposite side. The Wong-Baker Facial Pain scale (WBFPS), Face Leg Activity Cry, and Consolability (FLACC), and physiologic parameters were used to assess pain perception. Results: The independent t-test showed no statistically significant difference in blood pressure and heart rate before and after extraction (P > 0.05). The mean FLACC index in the lidocaine and articaine groups was 0.89 and 1.36, respectively; there was no statistically significant difference between them (P > 0.05). According to the results of the chi-square test, there was no statistically significant difference between the groups for WBFPS (P > 0.05). Conclusion: The articaine infiltration technique may be an alternative to the IANB for the extraction of primary mandibular molars.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.53-59
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• 2022

Static seals are used to seal high temperature gas and cryogenic fluid under high pressure, at interfaces between liquid rocket engine components such as combustion chamber, turbopump, gas generator, valves, etc. As thermal expansion and contraction at assembly interfaces cause undesirable leakage under cryogenic and high temperature environments, static seals applied for sealing of joint interfaces without relative motion should be designed properly. The additional function of rotation at the sealing face is also required for static seals, when the spherical flange is used for improvement of assembly at misalignment interfaces. In this study, structural analysis and leak tightness test of simulating test rig for several important interfaces are performed, to verify structural integrity of static seals.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.728-731
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• 2010

현대 사회에서 운동 부족의 원인은 바로 빠른 삶을 추구하는 우리나라 사람들의 성향에 있다고 볼 수 있다. 이런 현대사회에서 빠른 삶을 추구할수록 사람들은 단기간에 많은 효과를 보려고 무리한 운동을 한다. 갑작스러운 운동은 우리 몸에 이로운 것이 아니라 스트레스를 쌓이게 하고 이렇게 쌓인 스트레스는 고혈압, 심근경색, 뇌졸중 등 심혈관계 질환에 영향을 미치는 중요한 위험요인이다. 혈압은 정서적 긴장이나 주위 환경 및 활동에 따라서 변동하기 때문에 갑작스런 운동은 혈압에 좋지 않은 영향을 줄 수 있다. 이에 본 논문에서는 갑작스런 운동량에 따른 혈압 변화와 얼굴색과의 상관성을 알아보기 위해 운동량에 따른 혈압 변화와 얼굴 영역 추출 후 얼굴영역에 나타나는 색상 변화를 Lab 값 중 a값의 변화를 비교, 분석하였다.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1028-1035
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• 2005

Traditional Industries were planning the major role for Taiwan's economy. However, we need to face the competition from developing countries. Moving manufacturing department to other low salary countries, such as China, can only temporarily release some limited pressure. The final and complete solutions are to equip on R&D, refine techniques, improve management capabilities, upgrade business, and reform physique. Currently there are some ERP systems on the market; however, they are designed for common purpose and difficult to introduce into industry. The expensive price is another factor to make them be popular. In this research we will Object Oriented, Visual Modeling, ER Model and Windows Environment to develop an Integrated Management System for Sports Requisites Industries (IMSSRI). We will integrate all information from all departments such as development, business, material administration, manufacture, shipping, and financial. When development people construct the all modules, components, cutting molds, materials and accessories, IMSSRI will calculate all needed materials and cost for each product. This cost will be used for quotation to report to our customers. When customers confirm the order, system will transfer all necessary materials into Material Administration System. IMSSRI can generate manufacturing forms and material raw lists for manufacture department. All related information such as stocking, returning goods, material requesting, and material returning can be integrated so we can control all details of the whole enterprise. Through the help of this system, we hope we can save man-power, reduce human mistakes, raise management capabilities for tradition manufacturing industries and create another possibility of eternal operating for Taiwan's Industries.

• Journal of Oral Medicine and Pain
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• v.47 no.4
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• pp.189-197
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• 2022

Purpose: Pain perception is affected by a wide range of contributing factors, including biological, psychological, and social factors. Although the provision of visual information could have a modulatory effect on pain perception, it is unclear whether such a visual effect might vary depending on the anatomical site and stimulation type. This study aimed to analyze the modulatory effect of visual information on the perception of sharp and dull pain in the face and hand and to assess the influence of individual fear levels on modulatory visual information. Methods: A total of 68 healthy male and female volunteers were recruited for this study. Pressure and pricking pain with and without visual information were induced on the masseter and thenar muscles, and alterations in pain threshold were evaluated. The survey was conducted using the Geop-Pain Questionnaire (GPQ). Results: The pricking pain threshold of the hand was significantly elevated when viewing the stimulated hand. This result indicated that the provision of visual information could decrease sensitivity to sharp pain in the hand. However, when correlating the GPQ score with the alteration in thresholds induced by visual information, no significant correlation was observed between the GPQ score and the threshold difference induced by visual information. This finding showed that the visual effect was not significantly affected by the fear level. Conclusions: This study showed that the effect of visual information on the pain threshold could vary according to the anatomical site and stimulation type. A better understanding of such a modulatory effect on pain perception might be useful for clinicians during painful therapeutic procedures.