• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.12
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• pp.1749-1755
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• 2002

본연구의 목적은DP가공에 의한 가교화를 통해 텐셀의 피브릴화를 조절할 때 DP가공 방법 및 NaOH전처리 효과를 물성, 표면형태, 역학적 성질 및 태의 변화의 관점에서 고찰하는데 있다. SEM 분석결과DP가공에 의해 피브릴 발생 정도는 감소하였다. DP가공 방법에 있어 서 WF법과 PDC법에 따른 물성의 차이는 나타나지 않았다. 역학적특성의 경우 DP가공은 DP가공 방법에 상관없이 효소처리한 직물의 인장선형성에는 큰 영 향을 주지 않았으나 인장에 너지, 굽힘 강성, 압축선형성, 압축 레질리언스, 기하학적 거칠기는 감소시켰고 인장 레질리언스, 굽힘이력, 압축에너지는 증가시켰다. 전단특성은 WF법에서는 증가한 반면, PDC법에서는 감소하여 DP가공 방법에 따른 차이를 나타내었다. WF법이 PDC법보다 더 높은 Koshi, Numeri, Fukurami 값을 보였으며, 종합태 값은 비슷하게 나타났다. NaOH 전처 리에 의해 수지부착량은 감소하였으나 감량률은 증가하였으며, DP성/물성은 더 낮게 나타났다. NaOH 전처리에 의해 인장선형성, 인장에너지, 압축 레질리언스, 전단 및 굽힘특성은 증가하였으나 인장레질리언스와 압축선형성, 압축에너지, 표면특성은 감소하였다. NaOH 전처리한 경우 Koshi는 증가하였고, Numrei와 Fukuramil는 감소하였으며, 종합태 값은 가장 낮았다. 처리한 시료들은 각각 다른 감성과 촉감을 나타냈다.

• Journal of Digital Contents Society
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• v.6 no.3
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• pp.175-178
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• 2005

Wirtual reality(VR) is both one of the high-technology and main paradime in leading next genaration of 21th century. It`s application spectrum is various and lead to numorous revolotion as well as transtion in technical aspect. These change is a good procept of it`s comes to receive at real-time tracking using Web-Cam. The method research which is the possibility of doing location tracking which is accurate.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.396-404
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• 2009

With developing the next generation high speed railway, there need to be plans to make sure of running safety though researchs on the crack and break of rail by rolling contact fatigue. Therefore, this study performed the parametric analysis effecting on the fatigue life of rail using simplified equations. It analyzed the internal stress of rail according to the track quality, train velocity, wheel radius, track stiffness, sleeper space, wheel load. For the more, via the finite element method, it analyzed shear force on the rail head which could be changed by the early length of crack, angle of crack and temperature. As a result, this study continued the main parameter effecting on the fatigue life of rail.

• Computational Structural Engineering
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• v.11 no.1
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• pp.171-178
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• 1998

The added viscoelastic dampers increase damping and stiffness of buildings and results in so called non-classical or non-proportional damping problem. In this system the eigenvectors of the undamped system may not diagonalize the damping matrix, and the system is generally analyzed by converting the equation of motion into a 2n first order state-space form. As this approach is complex and time-consuming compared to the classically damped problem, the system is often analyzed by neglecting the off-diagonal terms in the damping matrix. In this paper the theoretical background of the approximate approach is studied, and the vibration characteristics of a three-story shear building with a viscoelastic damper are investigated using the exact and approximate method. It is found that the approximate method may produce good result when the additional damping is small, but as the damping increases the error also increase.

• Geotechnical Engineering
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• v.11 no.2
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• pp.5-18
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• 1995

A Compaction-induced lateral earth pressure was measured for a reversed-T type retaining wall of 4m high for three months. As a result of in-situ measurements, the lateral earth pressure fluctuated sharply with time after backfill, which was closely dependent upon the displacement of the retaining wall. The measured results showed big discrepancy with theoretical predictions made by existing theories, which are applicable to rigid wall. However, the in -situ data twas compared relatively well with those obtained by the finite element method. Analysis showed that the discrepancy may be caused by the displacement of the retaining wall during the compaction of the backfill.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.129-135
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• 1996

The area of gear vibration and noise, has recently been the focus of many studies. The proper kinematic and geometric design of gears, the mathematical modeling of gear system are essential for a good design. This work present a gear disign for reducing noise, and practical approaches used for machinery noise reduction slong with the summary of methods available for predicting gear noise in terms of the transmis- sion error, and show a comparative study with other methods. A new tooth profile modification is proposed for reducing vibration and noise of involute gears. The method is based on the use of cubic spline curves. The tooth profile is constrained to assume an involute shape during the loaded operation. Thus the new gear profile assures conjugate motion at all points along the line of action. The new profile is found to result in a more uniform static transmission error compared to not only standard involute profile but also modificated profile therby contributing to the improvement of vibration and noise characteristics of the gear.

• Horticultural Science & Technology
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• v.18 no.2
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• pp.93-97
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• 2000

This study was conducted to determine the appropriate osmotic priming chemicals and their concentrations to improve germination of carrot, lettuce, onion, and Welsh onion seeds. Each chemical, including $KNO_3$, $KH_2PO_4$, $K_3PO_4$, NaOH, $Ca(NO_3)_2$, and PEG 8000, was tested at three to four concentrations. Percent germination, number of days to attain 50% of the final germination percentage (T50), and mean number of days to germination (MDG) of primed seeds were compared with those of water-imbibed or nonprimed seeds. With the exception of 100 or 200 mM NaOH, other priming chemicals did not affect percent germination of carrot and lettuce seeds. However, the chemical priming did reduce T50 and MDG, especially with -0.5 MPa PEG 8000 for carrot and with 50 mM $K_3PO_4$ or 200 mM $KH_2PO_4$ for lettuce. Among the chemicals with no influence on percent germination did 200 mM $KH_2PO_4$ significantly reduced both T50 and MDG of onion seeds. No chemicals improved percent germination of Welsh onion seeds. Reduction in T50 and MDG was significant only with $KH_2PO_4$ and $Ca(NO_3)_2$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.31-43
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• 2009

In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations of motion. The coupled equations of motion for the vehicle-bridge interaction are solved by the Newmark ${\beta}$ of a direct integration method, and by composing the effective stiffness matrix and the effective force vector according to a analysis step, those can be solved with the same manner of the solving procedure of equilibrium equations in static analysis. Also, the effective stiffness matrix is reconstructed by the Skyline method for increasing the analysis effectiveness. The Cholesky's matrix decomposition scheme is applied to the analysis procedure for minimizing the numerical errors that can be generated in directly calculating the inverse matrix. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 16 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by the PSD functions of the Federal Railroad Administration (FRA). The results of the vehicle-bridge interaction analysis are verified by the experimental results for the railway plate girder bridges of a span length with 12 m, 18 m, and the experimental and analytical data are applied to the low pass filtering scheme, and the basis frequency of the filtering is a 2 times of the 1st fundamental frequency of a bridge bending.

• Food Science and Preservation
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• v.9 no.1
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• pp.42-45
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• 2002

Variations of cyanogenic glucoside was investigated on varieties, picking date, each part and processed flood of Ume. First, variation of amygdalin contents was determined by HPLC during ripening. As a result in case of peels, Oshuku showed most highest content(20.2 mg%) in all varieties. In case of seeds, Native species showed most highest content(562 mg%), and seeds contented more than peels. And then, variation of prunasin contents was determined by HPLC. As a results in case of peels, native species contented most lowest prunasin in all varieties, and its contents slightly decreased with increased storage periods. Other hand, in case of seeds, native species contented most highest prunasin(177 mg%). Contents of amygdalin and prunasin of extracts was determined by HPLC during six month ripening. As a result, in case of freezing storages contents of those not changed hardly during ripening. But, in case of native storage, contents of amygdalin was decreased and prunasin was increased with increased aging periods. Profile of Ume tea was similar to extracts of it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.570-576
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• 2007

In this study, the characteristics of metal-ferroelectric-semiconductor FET (MFSFET) device is investigated using field-dependent polarization and square-law FET models. From drain current with the gate voltage variation, when coercive voltages of ferroelectric thin film are 0.5 and 1V, the memory windows are 1 and 2V, respectively. When the gate voltages are 0, 0.1, 0.2 and 0.3V, the difference of saturation drain currents of the MFSFET device at two threshold voltages in ID-VD curve are 1.5, 2.7, 4.0, and 5.7mA, respectively. As a result of the analysis for drain currents after tine lapse, which is based on the simulation for hysteresis loop and the fitting of retention properties of ferroelectric thin films such as PLZT(10/30/70), PLT(10) and PZT(30/70) thin film shows excellent reliability that the decrease of saturation current is about 18% after 10 years.