The accelerator pedal of a KLTV was applied in the form of a carryover utilizing the products of a civilian vehicle. There was case in which it was damaged because it did not reflect the military's specificity, Therefore the material and shape of the accelerator pedal were improved to confirm the strength improvement effect of about 86%, It can prevent accidents and contribute to securing mobility by presenting and applying fracture strength standards suitable for the military operation environment.
The center bearing of the propeller shaft in the KM-Sam mounted vehicle is a component that requires high durability due to high-speed rotation and it must exhibit strong resistance to vibration and strees. However some Republic of Korea Air Force (ROKAF) units have experienced failures where the center bearing bracket breaks, leading th the detachment of the propeller shaft assembly. This issue has only occurred with domestically developed center bearings, A root cause analysis confirmed excessive second-order components and stress, Therefore improved results were derived through comparative testing with imported parts, and the effectivenss was verified by applying them to actual vehicles.
This study deeply discusses the development status of e-learning in basic music education in China, and summarizes the characteristics and development of music education course content, resources, evaluation and certification in the three countries through comparative analysis with e-learning platforms in South Korea and the United States, revealing the development trends and differences of global online music teaching. In the strategic analysis part, it is pointed out that, firstly, the development of basic music online teaching needs to be combined with online and offline hybrid teaching to promote the development of music education. Secondly, while learning from the advanced experience of e-learning in other countries, we should pay attention to innovative education methods、 expand the subject content. Finally, we should pay attention to the cultivation of students' learning ability to facilitate the establishment of an efficient learning model. The innovation of this paper lies in the comprehensive and in-depth research and comparison of the characteristics and case analysis of e-learning in music education in China, and at the same time, combined with the experience of South Korea and the United States, the implementation conditions and strategies for the situation in China are proposed, which provides strong theoretical support and practical guidance for the development of e-learning in music education in China based on the practical experience of different countries, and provides specific suggestions for further optimizing the practice of online music teaching.
Combat vehicles were developed in two types depending on the purpose of operation. The body of the vehicle is relatively large welded structure, and there is a quality problem in that welding deformation occurs in a certain area. Welding deformation is a problem that is inevitably generated during the welding process, and additional corrective work is performed. However, due to the structural characteristics of the welded structure of combat vehicl, there are many limitations in the correction method, which lowered the productivity. To improve this problem, we intend to establish improvement measures through analysis of the areas where welding deformation occurs and apply corrective measures suitable for welding structures of combat vehicles. For the design improvement plans, the finite element analysis were used and the correction method were applied to simulated structure to confirm the possibility. Finally, the improvement effect was confirmed by manufacturing the actual welded structure. Based on the results of this study, it is expected that the productivity of related similar welding structures as well as structures of wheeled armored vehicles, can be improved.
The purpose of this study is to improve the durability by solving the crack problem of the steering gearbox bracket welded to the frame assembly. For the exact and effective analysis, we use charac- teristic(fishbone) diagram from the viewpoint of 4M1E. Through this analysis it was identified two kinds of problems, and develop improvement plan for it. Verification tests must be performed to confirm the improvement. So, the test method for steering gearbox bracket improvement was newly established by referring to similar case. As a result of the tests for verification, the stresses at crack point are decreased and the durability was improved about 2.6 times compared with product before improvement.
Si3N4 is a ceramic material attracting attention in many fields because of its excellent abrasion resistance. In addition, Ti and TiAl alloys are metals used in a variety of high temperature environments, and have attracted much attention because of their high strength and high melting points. Therefore, study of the interface reaction between Si3N4 / Ti and Si3N4 / TiAl can be a useful practice to identify phase selection and diffusion control. In this study, Si3N4 / Ti5Si3 + TiN / TiN / Ti diffusing pairs were formed in the Si3N4 / Ti interfacial reaction and Si3N4 / TiN(Al) / Ti3Al / TiAl diffusion pathway was identified in the Si3N4 / TiAl interfacial reaction. The diffusion layers of the interface reactions were identified and, to investigate the kinetics of the diffusion layer, the integrated diffusion coefficients were estimated.
Fatigue crack growth rate tests were conducted as a function of temperature, dissolved hydrogen (DH) level, and frequency in a simulated PWR environment. Fatigue crack growth rates increased slightly with increasing temperature in air. However, the fatigue crack growth rate did not change with increasing temperature in PWR water conditions. The DH levels did not affect the measured crack growth rate under the given test conditions. At 316 oC, oxides were observed on the fatigue crack surface, where the size of the oxide particles was about 0.2 μm at 5 ppb. Fatigue crack growth rate increased slightly with decreasing frequency within the frequency range of 0.1 Hz and 10 Hz in PWR water conditions; however, crack growth rate increased considerably at 0.01 Hz. The decrease of the fatigue crack growth rate in PWR water condition is attributed to crack closure resulting from the formation of oxides near the crack tips at a rather fast loading frequency of 10 Hz.
In this study, BaTiO3 thin films were grown by RF-magnetron sputtering, and the effects of the thin film thickness on the structural characteristics of BaTiO3 thin films were systematically investigated. Instead of the oxide substrates generally used for the growth of BaTiO3 thin films, p-Si substrates which are widely used in the current semiconductor processing, were used in this study in order to pursue high efficiency in device integration processing. For the crystallization of the grown thin films, annealing was carried out in air, and the annealing temperature was varied from 700˚C. The changed thickness was within 200 nm~1200 nm. The XRD results showed that the best crystal quality was obtained for ample thicknesses 700 nm~1200 nm. The SEM analysis revealed that Si/BaTiO3 are good quality interface characteristics within 300 nm when observed thickness. And surface roughness observed of BaTiO3 thin films from AFM measurement are good quality surface characteristics within 300 nm. Depth-profiling analysis through GDS (glow discharge spectrometer) showed that the stoichiometric composition could be maintained. The results obtained in this study clearly revealed BaTiO3 thin films grown on a p-Si substrate such as thin film thickness. The optimum thickness was 300 nm, the thin film was found to have the characteristics of thin film with good electrical properties.
Although the sparganosis involving soft tissues, i.e, tongue, cheek, etc., has been frequently reported, the mandibular involvement of sparganosis is not reported up to date. We present a case of intraosseous sparganosis involving whole mandible, which was clinically diagnosed as chronic osteomyelitis. After surgical operation of saucerization for the treatment of chronic osteomyelitis the removed specimens were pathologically examined and finally turned out intraosseous sparganosis. Radiological findings showed irregular multiple radiolucencies in round to ovoid shape throughout both mandibular body areas, of which peripheral rarefying radiopacity was less remarkable compared to the ordinary osteomyelitis. However, the radiolucencies of periapical granuloma, #34-36, were closely associated with the osteolytic lesions of mandibular body. Pathological examination showed a tunnel like space for the passage of sparganum larva, and heavy infiltration of eosinophilicleukocytes. And more, the parasitic tegument materials were found admixed with eggs in the granulomatous lesion, which were gradually degraded and resolved. Taken together, we presumed that the mandibular inflammatory lesion was primarily involved with sparganosis and secondarily aggravated by the periapical infection of #34-36.
Catch of garden thrips, Frankliniella intonsa, on sticky traps was assessed by color and height in commercial plastic vinyl house strawberry crops grown on 40-㎝-high trellises. Yellow, blue and white sticky cards were tested for color attractiveness, and upper (50 ㎝), lower (10 ㎝ above the floor) and ground were for height. At each height, trapped thrips on yellow, blue and white were significantly different. Blue sticky cards were significantly greater than traps on yellow and white. The trapped thrips were also significantly greatest at 50 ㎝ above the floor, less at lower and ground. However, there is no significantly different the population of garden thrips on the flower in each tested site.