• Title/Summary/Keyword: Attenuation equation

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Exposure Time and X-Ray Absorber thickness in the LIGA Process (LIGA 공정에서의 노광시간과 X선마스크 흡광체의 두께)

  • 길계환;이승섭;염영일
    • Journal of the Korean Vacuum Society
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    • v.8 no.2
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    • pp.102-110
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    • 1999
  • The LIGA X-ray exposure step was modelled into three inequalities, by assuming that the X-ray energy attenuated within a resist is deposited only in the localized range of the resist. From these inequalities, equations for the minimum and maximum exposure times required for a good quality microstructure were obtained. Also, an equation for the thickness of an X-ray mask absorber was obtained from the exposure requirement of threshold dose deposition. The calculation method of the synchrotron radiation power from a synchrotron radiation source was introduced and applied to an X-ray exposure step. A power from a synchrotron radiation source was introduced and applied to an X-ray exposure step/ A power function of photon energy, approximating the attenuation length of the representative LIGA resist, PMMA, and the mean photon energy of the XZ-rays incident upon an X-ray mask absorber were applied to the above mentioned equations. Consequently, the tendencies of the minimum and maximum exposure and with respect to mean photon energy and thick ness of PMMA was obtained. Additionally, the tendencies of the necessary thickness of PMMA and photon energy of the X-ray mask absorber with respect to thickness of PMMA and photon energy of the X-rays incident upon an X-ray mask absorber were examined. The minimum exposure time increases monotonically with increasing mean photon energy for the same total power density and is not a function of the thickness of resist. The minimum exposure time increases with increasing mean photon energy for the same total power density in the case of the general LIGA process, where the thickness of PMMA is thinner than the attenuation length of PMMA. Additionally, the minimum exposure time increases monotonically with increasing thickness of PMMA. The maximally exposable thickness of resist is proportional to the attenuation length of the resist at the mean photon energy with its proportional constant of ln $(Dd_m/D_{dv})$. The necessary thickness of a gold X-ray mask absorber due to absorption edges of gold, increases smoothly with increasing PMMA thickness ratio, and is independent of the total power density itself. The simplicity of the derived equations has made clearly understandable the X-ray exposure phenomenon and the correlation among the exposure times, the attenuation coefficient and the thickness of an X-ray mask absorber, the attenuation coefficient and the thickness of the resist, and the synchrotron radiation power density.

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Ground Motion Evaluation from the Fukuoka Earthquake (후쿠오카 지진('05. 3. 20, M=7.0)의 지진동 감쇠특성 분석)

  • Park Donghee;Yun Kwanhee;Chang Chun-Joong;Choi Weon-Hack;Lee Dae-Soo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.87-92
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    • 2005
  • The ground-motion (GM) attenuation relations available in Korea has required the validation process for large earthquakes since most of them were developed based on small earthquake database, The Fukuoka earthquake (M=7.0) that occurred near the Korean Peninsula provides invaluable data to indirectly evaluate the attenuation characteristics of the strong GM in Korea. The GM levels (PGA, SA) obtained from the KIK-net downhole stations near the epicenter (R<100km) are reasonably predicted by the GM attenuation relation developed by KEPRI in 2003 for the Kori NPP site, the result of which validates the use of KEPRI GM attenuation relation for predicting GM induced by future large earthquakes. Also, the comparison between the Osaki spectra and response spectra of KIK-net downhole data reveals that the amplitude levels of Osaki spectra are higher than the spectra from KIK-net stations which are believed to be installed at the seismic basement.

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Ground Motion Evaluation from the Fukuoka Earthquake (후쿠오카 지진('05. 3. 20, M=7.0)의 지진동 감쇠특성 분석)

  • Park, Dong-Hee;Yun, Kwan-Hee;Chang, Chun-Joong;Choi, Weon-Hack;Lee, Dae-Soo
    • Journal of the Korean Geophysical Society
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    • v.8 no.3
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    • pp.109-113
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    • 2005
  • The ground-motion (GM) attenuation relations available in Korea has required the validation process for large earthquakes since most of them were developed based on small earthquake database. The Fukuoka earthquake (M=7.0) that occurred near the Korean Peninsula provides invaluable data to indirectly evaluate the attenuation characteristics of the strong GM in Korea. The GM levels (PGA, SA) obtained from the KIK-net downhole stations near the epicenter (R<100km) are reasonably predicted by the GM attenuation relation developed by KEPRI in 2003 for the Kori NPP site, the result of which validates the use of KEPRI GM attenuation relation for predicting GM induced by future large earthquakes. Also, the comparison between the Osaki spectra and response spectra of KIK-net downhole data reveals that the amplitude levels of Osaki spectra are higher than the spectra from KIK-net stations which are believed to be installed at the seismic basement.

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Stochastic Prediction of Strong Ground Motions in Southern Korea (추계학적 보사법을 이용한 한반도 남부에서의 강지진동 연구)

  • 조남대;박창업
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.4
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    • pp.17-26
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    • 2001
  • In order to estimate peak ground motions and frequency characteristics of strong ground motions in southern korea, we employed the stochastic simulation method with the moment magnitude(M$_{w}$) and the hypocentral distance(R). We estimated same input parameters that account for specific properties of source and propagation processes, and applied them to the stochastic simulation method. The stress drop($\Delta$$\sigma$) of 100-bar was estimated considering results of research in ENA, China, and southern korea. The attenuation parameter x was calculated by analyzing 57 seismograms recorded from September 1996 to October 1997 and the estimation result of the attenuation parameter x is 0.00112+0.000224 R where R is hypocenter distance. We estimated strong ground motion relations using the stochastic simulation method with suitable input parameters(e.g. $\Delta$$\sigma$, x, and so on). At last, we derived relations between hypocentral distances and ground motions(seismic attenuation equation) using results of the stochastic prediction.esults of the stochastic prediction.n.

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Analysis of Uniform Hazard Spectra for Metropolises in the Korean Peninsula (국내 주요 광역 도시에 대한 등재해도 스펙트럼 분석)

  • Rhee, Hyun-Me;Kim, Min Kyu;Sheen, Dong-Hoon;Choi, In-Kil
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.2
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    • pp.71-77
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    • 2013
  • The uniform hazard spectra for seven major cities in Korea, Seoul, Daejeon, Daegu, Busan, Gwangju, Ulsan, and Inchon are suggested. Probabilistic seismic hazard analyses were performed using the attenuation equations derived from seismology research in Korea since 2000 and the seismotectonic models selected by expert assessment. For the estimation of the uniform hazard spectra, the seismic hazard curves for several frequencies and PGAs were calculated by using the spectral attenuation equations. The seismic hazards (annual exceedance probability) calculated for the 7 metropolises ranged from about $1.4305{\times}0^{-4}/yr$ to $1.7523{\times}10^{-4}/yr$ and averaged out at about $1.5902{\times}10^{-4}/yr$ with a log standard deviation of about 0.085 at 0.2 g. The uniform hazard spectra with recurrence intervals of 500, 1000, and 2500 years estimated by using the calculated mean seismic hazard on the frequencies presented peak values at 10.0 Hz, and the log standard deviations of the difference between metropolises ranged from about 0.013 to 0.209. In view of the insignificant difference between the estimated uniform hazard spectra obtained for the considered metropolises, the mean uniform hazard spectrum was estimated. This mean uniform hazard spectrum is expected to be used as input seismic response spectrum for rock sites in Korea.

Propagation characteristics of blast-induced vibration to fractured zone (파쇄영역에 따른 발파진동 전파특성)

  • Ahn, Jae-Kwang;Park, Duhee;Park, Ki-Chun;Yoon, Ji Nam
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.6
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    • pp.959-972
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    • 2017
  • In evaluation of blast-induced vibration, peak particle velocity (PPV) is generally calculated by using attenuation relation curve. Calculated velocity is compared with the value in legal requirements or the standards to determine the stability. Attenuation relation curve varies depending on frequency of test blasting, geological structure of the site and blasting condition, so it is difficult to predict accurately using such an equation. Since PPV is response value from the ground, direct evaluation of the structure is impractical. Because of such a limit, engineers tend to use the commercial numerical analysis program in evaluating the stability of the structure more accurately. However, when simulate the explosion process using existing numerical analysis program, it's never easy to accurately simulate the complex conditions (fracture, crushing, cracks and plastic deformation) around blasting hole. For simulating such a process, the range for modelling will be limited due to the maximum node count and it requires extended calculation time as well. Thus, this study is intended to simulate the elastic energy after fractured zone only, instead of simulating the complex conditions of the rock that results from the blast, and the analysis of response characteristics of the velocity depending on shape and size of the fractured zone was conducted. As a result, difference in velocity and attenuation character were calculated depending on fractured zone around the blast source appeared. Propagation of vibration tended to spread spherically as it is distanced farther from the blast source.

Application of Boussinesq Equation Model for the Breaking Wave Behavior around Underwater Shoals (수중 천퇴에서의 쇄파거동 예측을 위한 Boussinesq 방정식 모델의 적용)

  • Chun, In-Sik;Kim, Gui-Dong;Sim, Jae-Seol
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.18 no.2
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    • pp.154-165
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    • 2006
  • In the present study, a numerical model using Boussinesq equation is set up to predict the interacted equilibrium between waves and their induced currents in the occurrence of breaking waves over an underwater shoal, and the numerical results are compared with results of existing hydraulic experiments. A sensitivity analysis has been done to find out appropriate values of breaking wave parameters with the result (regular wave case) of Vincent and Briggs (1989)’ experiment. Then the numerical model is applied to the irregular wave cases of the experiment and the hydraulic model test of Ieodo which is a natural undersea shoal. The results show that a strong current forms in the wave direction at the downstream side of the shoals, causing the attenuation of wave heights there. The calculated wave heights generally show a similar pattern with the measured data.

Measurement and Control of Ground Vibrations due to Precast Concrete Pile-driving by Diesel Hammer (디젤해머에 의한 콘크리트말뚝 항타시(抗打時) 발생(發生)되는 지반진동(地盤振動)의 측정(測定) 및 영향평가(影響評價))

  • Park, Yean Soo;Chon, Chun Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.9 no.1
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    • pp.71-78
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    • 1989
  • This Paper measures and analyzes ground vibrations induced during precast concrete pile-driving using diesel hammer at radii varying from 9m to 30m to evaluate effects of such vibrations associated with deep foundation piling operations near the residential of commercial areas. From this study, characteristics for attenuation and frequency of the vibrations casued by pile-driving are established and the empirical equation for predicting peak velocity and acceleration levels are obtained. This equation can be used to predict the peak vibration levels and select the appropriate hammers for future projects where similar soil conditions to this test site are encountered.

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Representation of fundamental solution and vibration of waves in photothermoelastic under MGTE model

  • Rajneesh Kumar;Nidhi Sharma;Supriya Chopra;Anil K. Vashishth
    • Ocean Systems Engineering
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    • v.13 no.2
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    • pp.123-146
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    • 2023
  • In this paper, Moore-Gibson-Thompson theory of thermoelasticity is considered to investigate the fundamental solution and vibration of plane wave in an isotropic photothermoelastic solid. The governing equations are made dimensionless for further investigation. The dimensionless equations are expressed in terms of elementary functions by assuming time harmonic variation of the field variables (displacement, temperature distribution and carrier density distribution). Fundamental solutions are constructed for the system of equations for steady oscillation. Also some preliminary properties of the solution are explored. In the second part, the vibration of plane waves are examined by expressing the governing equation for two dimensional case. It is found that for the non-trivial solution of the equation yield that there exist three longitudinal waves which advance with the distinct speed, and one transverse wave which is free from thermal and carrier density response. The impact of various models (i)Moore-Gibson-Thomson thermoelastic (MGTE)(2019), (ii) Lord and Shulman's (LS)(1967) , (iii) Green and Naghdi type-II(GN-II)(1993) and (iv) Green and Naghdi type-III(GN-III)(1992) on the attributes of waves i.e., phase velocity, attenuation coefficient, specific loss and penetration depth are elaborated by plotting various figures of physical quantities. Various particular cases of interest are also deduced from the present investigations. The results obtained can be used to delineate various semiconductor elements during the coupled thermal, plasma and elastic wave and also find the application in the material and engineering sciences.

Seismic Landslide Hazard Maps in Ul-Ju Ul-san Korea (지진에 대한 사면의 재해위험지도 작성 - 울산시 울주군 지역을 중심으로-)

  • 조성원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.04a
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    • pp.89-96
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    • 2000
  • Landslide damage comprise most part of the damages from the earthquake and it only causes the damage to lives and structures directly but also cease the operation of social system by road or lifeline failure. For these reasons hazard assesment on the landslides has been recognized very important. And hazard maps have been used to visualize the hazard of the landslide. In this study as first step for application of hazard map to domestic cases hazard maps are made for the Ul-Joo Ul-san Korea, Where the Yan-san faults are located. For building hazard maps the degree of hazard are evaluated based on Newmark displacement and the resulting maps are constructed by GIS technique. In hazard assesment maximum ground acceleration obtained from attenuation equation of wave propagation and design earthquake acceleration suggested by Ministry of construction are used for acceleration term. Hazard maps are made by GIS programs Arc/Info and Arc/View based on the digital maps and data from lab tests and elastic wave surveys The maps show the possible landslide regions significantly and the displacements of slide are proportional to the slope angles.

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