• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.4 s.19
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• pp.36-43
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• 2004

In 1909 Hiram P. Maxim invented one of the first metal silencers for reducing sound levels in firearms. Silenced me have been mainly applied in the hunting and military operation. In particular special force make use of silenced rifle because it is low sound level. This paper considers experimental analysis for the characteristics of shock wave caused by shooting of a silenced me. Experimental results Indicate that the sound level of K-7 silenced rifle was lower than the sound level of MP5 silenced rifle. And, Sound Power Level of K-7 silenced rifle at a distance more than 75m or loom have nearly the constant value. This results that suggested the characteristics data about K-7 rifle's impulse noise will be apply to design the silencer of a small arms.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.89-93
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• 2003

The failure of rock slopes were influenced by weathering, which causes change in the shear strength. The weathering is also directly related to slaking and swelling characteristics. In the paper, the core of diameter loom was obtained by digging on rock slope of Kong-ju in Korea and then EDX(Energy Dispersive X-ray spectrometer) analysis was carried out to verified element of chief rock-forming minerals. Uniaxial compression tests, slaking tests, and point load test are performed to study engineering characteristics of conglomerate and red shale. As a results of slaking test, slaking index of conglomerate indicate range of 85.11-99.58 and shale indicate 58.37-99.23. Therefore, it is recognized that the resistance of shale to weathering decreases in shallow depth and it greatly influences the strength of rock. The result of uniaxial compression test and Point load test show that the strength of sedimentary such as conglomerate and red shale has an influence on both weathering and saturation.

• Journal of Biosystems Engineering
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• v.21 no.3
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• pp.343-356
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• 1996

The plot geometry of the paddy land is directly related to the performance of machines, especially those having a large size and high speed. The study was to investigate the optimum plot geometry from the standpoint of mechanization. A simulator, Field-Plot-Structure-Evaluation-System(FPSES) was developed for evaluation of the field performance of machines according to the plot geometry. The efficiency and capacity of different sizes of machinery used for rice farming functions were analyzed for a various combination of plot geometry, which could be used as reference for the land reclamation planning and mechanization programming. It is shown that the plot size of about two hectares having a length of 200m and width of loom may be optimum, considering the efficiency and capacity of large sized machinery available currently and in near future.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.285-290
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• 2002

The double composite box girder is a structural system filled with concrete at the bottom of the steel box in the negative moment region increasing the flexural strengths. Flexural strengths of the double composite steel box girders are investigated through a series of the experimental tests and the numerical analysis. The experimental tests are performed on the three kinds of steel box girders with the different concrete depths including loom, 15cm, and 20cm. Moment-curvature relations are calculated based on the sectional analysis method describing the nonlinear natures of concrete and steel. In the finite element analysis the nonlinear nature of concrete is described based on the three dimensional four-parameter constitutive model recently developed and that of steel is described based on von Mises failure criterion. The ultimate flexural capacities of the box girders predicted using sectional analysis and finite element analysis show good agreement with those of the experiments.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.259-267
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• 1995

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated slut비e and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floe. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floe. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0mg/$\ell$ to 258 mg/$\ell$. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about loom in this study.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.213-216
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• 2001

A micro hole punching system was developed and micro holes of 100m in diameter were successfully made on brass sheets of loom in thickness. A micro punch made of tungsten carbide was designed to withstand the punch load, considering the buckling and the bending moment due to possible misalignment error. The punch was fabricated by the grinding process with diamond wheel. The die was designed considering the punch load and fabricated by micro electrodischarge machining process. In this system the stripper is designed to guide punch tip to minimize the possible misalignment. The punch was installed on a vertical stepper and the die was mounted on an X-Y translation unit. The precision motion controller controlled all motions of the micro hole punching system. In this study technical difficulties and solutions in the micro hole punching process were also discussed.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.77-82
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• 2007

In this paper, we described a design and implementation of a sensor node for environmental monitoring. The main focus of design for sensor nodes is to isolate MCU for treating sensors from the RF module for considering various communication environment. The second is to make the interface between MCU and varity of sensor. In addition, we choose a narrow band communication module, cc1020, for the admittance of Korea government comminication law. We also use a uC/OS-II as an operating system which is famous for 8bit MCUs. We showed that the communication performance is sufficient to use the communication module in a out-door environment through several experiments in that it is possible to transmit between loom distance through experiments in a mountain.

• Journal of Environmental Science International
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• v.7 no.3
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• pp.281-290
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• 1998

Thirty-eight sediment samples collected from the Youngsan River channel were analysed for Fe, Mn, Co, Cr, Cu, Nl, Zn and Pb to recognize the extent of contamination. Results showed that a wide range of contents was apparent far every metal over the study area. These differences have been mainly related to the textural variability of sediments. Exceptions to this were fecund in the contents of Cu, Zn, Pb and possibly Mn. The contents of Cu, Zn, Pb and Mn were particularly higher in the sediments loom the confluence of tributaries. Downstream profile of metal/Al ratios indicates that pollutant inputs from the Kwangju tributary are mainly responsible for enrichment of these metals in bed sediments of the Young-san River.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.535-539
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• 2001

In these days. the finite element method(FEM) is a very common method for not only a simple vibration analysis but also the optimization of structures. Since the finite element model may contain thousands of degree of freedom, the eigensolutions require extreme computing power, which will result in a serious time-consuming problem. Thus, many researchers have challenged to find more improved modeling techniques and calculating methods to overcome such problems. The Guyan reduction method and the substructure synthesis method are typical examples of such methods. Of the substructure synthesis method, the component mode synthesis method (CMS) is widely used for dynamic analysis of structure. In this study. for the efficient analysis of jet loom structure. Component Mode Synthesis was carried out. The results of the finite element program developed are compared with those of the commercial package program ANSYS for the validation of the program. The results obtained by the program showed a good agreement with those of ANSYS. The program will be further refined and verified by test to yield more accurate results.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.422-425
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• 2003

This study was carried out to apprehend the variation of quality of mine drainage in the abandoned Samtan coal mine. After closure of coal mine, although still pumping, water level in underground was raised to loom and the concentration of some elements such as Fe and Mn was elevated. At present, the worst pollution source in this area is too the acidic leachate drained from uncovered mine waste impoundment. The flow rate of mine drainage from the adit is ave. about 20,000t/d. If water were flooded and deteriorated due to stopping pumping, the impact of the mine drainage on the stream around the abandoned mine would be more severe. Therefore, It is considered that the prediction of water quality of mine drainage from the adit after stopping pumping will be very important with a view to establishing countermeasures.