Glacio-isostatic adjustment(GIA)and tectonic activity are important factors in the formation of marine terraces.Late Holocene wave-cut benches in the eastern part of the West Sea of Korea,also called the Yellow Sea,ca...Glacio-isostatic adjustment(GIA)and tectonic activity are important factors in the formation of marine terraces.Late Holocene wave-cut benches in the eastern part of the West Sea of Korea,also called the Yellow Sea,can be divided into two steps:531 cm above sea level(ASL)for the upper bench(T2)and 464-481 cm ASL for the lower bench(T1).Sediments on the benches a re classified into four units,and are interpreted to be beach deposits acco rding to gravel shape,textu re,and seaward inclination.The ove rlying sediment indicates that T2 was formed at approximately 530 cm ASL before 2900 yr BP,and T1 at approximately 460-480 cm ASL before 1520 yr BP.Late Holocene(4000-2000 yr BP)relative sea level(RSL)curves based on GIA models are inconsistent with the wave-cut bench elevations.Comparing T1 and T2 benches to the RSL curves of the West Sea,the upper and the lower benches were uplifted by approximately 5-8 m and 4-7 m,respectively.Although the area is several hundred kilometers away from plate boundaries,the high frequency of earthquakes in the West Sea may have induced the uplift of wave-cut benches during the last 2000 years.These indicate that the west coast of the Korean Peninsula(KP)should no longer be considered an area of subsidence,but be assigned to a regime of uplift during the late Holocene.展开更多
Centroid depth of earthquakes is essential for seismic hazard mitigation. But, various studies provided different solutions for the centroid depth of the damaging 2013 Lushan earthquake, thus hindering further studies...Centroid depth of earthquakes is essential for seismic hazard mitigation. But, various studies provided different solutions for the centroid depth of the damaging 2013 Lushan earthquake, thus hindering further studies of the earthquake processes. To resolve its centroid depth and assess the uncertainties, we apply the teleseismic cut and paste method to invert for centroid depth with teleseismic body waves in the epicentral distance of 300-90~. We performed the inversion for P waves only as well the case of both P and SH waves and found that both cases lead to depth solutions with difference less than 0.5 km. We also investigated the effects on depth inversion from azimuth gap of seismic stations, source duration, and comer fre- quency of filter. These various tests show that even azi- muthal distribution of seismic stations is helpful for accurate depth inversion. It is also found that estimate of centroid depth is sensitive to source duration. Moreover, the depth is biased to larger values when corner frequency of low-pass filter is very low. The uncertainty in the velocity model can also generate some error in the depth estimation （- 1.0 km）.With all the above factors consid- ered, the centroid depth of Lushan earthquake is proposed to be around 12 km, with uncertainty about 2 km.展开更多
Wave approach is used to analyze the longitudinal wave motion in one dimensional non-uniform waveguides.With assumptions of constant wave velocity and no wave conversion,there exist four types of non-uniform rods and ...Wave approach is used to analyze the longitudinal wave motion in one dimensional non-uniform waveguides.With assumptions of constant wave velocity and no wave conversion,there exist four types of non-uniform rods and corresponding traveling wave solutions are investigated.The obtained results indicate that the kinetic energy is preserved as a constant and the wave amplitude is inversely proportional to square root of the cross-sectional area of the rod.Under certain condition,there exists a cut-off frequency for the rod with variation in geometric or material properties,below which waves do not propagate along the non-uniform rod.For the rod with arbitrary variable cross-section, the conclusions are similar if the wave frequency is high enough.And a series solution of the wave motion is presented.展开更多
Surface acoustic wave (SAW) devices play a significant role in signal processing, frequency control and sensing applications. In general, they cannot operate at elevated temperature. The new crystal of langasite provi...Surface acoustic wave (SAW) devices play a significant role in signal processing, frequency control and sensing applications. In general, they cannot operate at elevated temperature. The new crystal of langasite provides possibility for surface acoustic wave devices applied at high temperature. This paper studies the SAW properties of single and doubly rotated cuts of LGS at high temperature. The calculated SAW properties of LGS are analyzed in space with aid of contour plots, and two promising SAW orientation regions at high temperature are presented. For some typical cuts and propagating directions within the two optimal regions, their SAW characteristics vs temperature are discussed. Based on the experimental evidence in some literatures, the reliability of calculated results is verified.展开更多
A multiscale simulation has been performed to determine the effect of the cutting speed on the deformation mechanism and cutting forces in nanometric cutting of single crystal copper. The multiscale simulation model, ...A multiscale simulation has been performed to determine the effect of the cutting speed on the deformation mechanism and cutting forces in nanometric cutting of single crystal copper. The multiscale simulation model, which links the finite element method and the molecular dynamics method, captures the atomistic mechanisms during nanometric cutting from the free surface without the computational cost of full atomistic simulations. Simulation results show the material deformation mechanism of single crystal copper greatly changes when the cutting speed exceeds the material static propagation speed of plastic wave. At such a high cutting speed, the average magnitudes of tangential and normal forces increase rapidly. In addition, the variation of strain energy of work material atoms in different cutting speeds is investigated.展开更多
Results are presented for the 3D numerical simulation of the water impact of a wave energy converter in free fall and subsequent heave motion. The solver, AMAZON-3D, employs a Riemann-based finite volume method on a C...Results are presented for the 3D numerical simulation of the water impact of a wave energy converter in free fall and subsequent heave motion. The solver, AMAZON-3D, employs a Riemann-based finite volume method on a Cartesian cut cell mesh. The computational domain includes both air and water regions with the air/water boundary captured automatically as a discontinuity in the density field thereby admitting break up and recombination of the free surface. Temporal discretisation uses the artificial compressibility method and a dual time stepping strategy. Cartesian cut cells are used to provide a boundary-fitted grid at all times. The code is validated by experimental data including the free fall of a cone and free decay of a single Manchester Bobber component.展开更多
The surface profile behavior of workpieces sawn has been investigated. Six species were sawn under the condi-tion of four different kinds of cutting speed by the band saw. The real surface profile of a sawn workpiecc ...The surface profile behavior of workpieces sawn has been investigated. Six species were sawn under the condi-tion of four different kinds of cutting speed by the band saw. The real surface profile of a sawn workpiecc is composed of twosections, which arc the additivity of the waviness of filtered wave and roughness curve. The roughness of center line avernge aswell as amplitude decrease with the increasing of cutting speed for different kinds of species used in the experiment.展开更多
为探究适用于制作卤煮牛肉的超声频率及牛肉部位,以牛腱、牛霖和牛米龙为原料,分别在0、20、28和50 k Hz条件下进行超声处理,通过测定色泽、蒸煮损失率、质构特性、嫩度及风味物质等指标,结合主成分分析(PCA)与模糊数学感官评价法综合...为探究适用于制作卤煮牛肉的超声频率及牛肉部位,以牛腱、牛霖和牛米龙为原料,分别在0、20、28和50 k Hz条件下进行超声处理,通过测定色泽、蒸煮损失率、质构特性、嫩度及风味物质等指标,结合主成分分析(PCA)与模糊数学感官评价法综合评估卤煮牛肉的品质。结果表明:超声辅助卤煮可显著改善各部位牛肉的色泽、保水性、质构特性及嫩度;GC-MS共鉴定出27种关键风味物质(OAV≥1);PCA分析显示,经20 k Hz超声处理的牛米龙所制得的卤煮牛肉综合品质最佳,该结果与模糊数学感官评价结果一致。研究为卤煮牛肉生产企业提供了科学、客观且具有较高应用价值的理论依据与技术参考,有助于提升产品品质和生产效率。展开更多
基金supported by grant 2017-MOIS31-006 from the Research and Development of Active Faults of Korea Peninsula funded by the Korean Ministry of Public Safety and Security (MPSS)by grant NP2018-017 from the Research on Geologic Hazard Assessment of Large Fault Systems Focusing on the Central Region of the Yangsan from the Basic Research Project of the Korea Institute of Geoscience+1 种基金Mineral Resources (KIGAM) funded by the Korean Ministry of Science and ICT.S.K.appreciate the partialsupport by the NRF-2017R1A6AIA07015374 (Multi-disciplinary study for assessment of large earthquake potentials in the Korean Peninsula)NRF-2019R1A2C1002211 through the National Research Foundation of Korea funded by the Ministry of Science and ICT,Korea
文摘Glacio-isostatic adjustment(GIA)and tectonic activity are important factors in the formation of marine terraces.Late Holocene wave-cut benches in the eastern part of the West Sea of Korea,also called the Yellow Sea,can be divided into two steps:531 cm above sea level(ASL)for the upper bench(T2)and 464-481 cm ASL for the lower bench(T1).Sediments on the benches a re classified into four units,and are interpreted to be beach deposits acco rding to gravel shape,textu re,and seaward inclination.The ove rlying sediment indicates that T2 was formed at approximately 530 cm ASL before 2900 yr BP,and T1 at approximately 460-480 cm ASL before 1520 yr BP.Late Holocene(4000-2000 yr BP)relative sea level(RSL)curves based on GIA models are inconsistent with the wave-cut bench elevations.Comparing T1 and T2 benches to the RSL curves of the West Sea,the upper and the lower benches were uplifted by approximately 5-8 m and 4-7 m,respectively.Although the area is several hundred kilometers away from plate boundaries,the high frequency of earthquakes in the West Sea may have induced the uplift of wave-cut benches during the last 2000 years.These indicate that the west coast of the Korean Peninsula(KP)should no longer be considered an area of subsidence,but be assigned to a regime of uplift during the late Holocene.
文摘Centroid depth of earthquakes is essential for seismic hazard mitigation. But, various studies provided different solutions for the centroid depth of the damaging 2013 Lushan earthquake, thus hindering further studies of the earthquake processes. To resolve its centroid depth and assess the uncertainties, we apply the teleseismic cut and paste method to invert for centroid depth with teleseismic body waves in the epicentral distance of 300-90~. We performed the inversion for P waves only as well the case of both P and SH waves and found that both cases lead to depth solutions with difference less than 0.5 km. We also investigated the effects on depth inversion from azimuth gap of seismic stations, source duration, and comer fre- quency of filter. These various tests show that even azi- muthal distribution of seismic stations is helpful for accurate depth inversion. It is also found that estimate of centroid depth is sensitive to source duration. Moreover, the depth is biased to larger values when corner frequency of low-pass filter is very low. The uncertainty in the velocity model can also generate some error in the depth estimation （- 1.0 km）.With all the above factors consid- ered, the centroid depth of Lushan earthquake is proposed to be around 12 km, with uncertainty about 2 km.
基金supported by the National Natural Science Foundation of China(11072157 and 10932006)
文摘Wave approach is used to analyze the longitudinal wave motion in one dimensional non-uniform waveguides.With assumptions of constant wave velocity and no wave conversion,there exist four types of non-uniform rods and corresponding traveling wave solutions are investigated.The obtained results indicate that the kinetic energy is preserved as a constant and the wave amplitude is inversely proportional to square root of the cross-sectional area of the rod.Under certain condition,there exists a cut-off frequency for the rod with variation in geometric or material properties,below which waves do not propagate along the non-uniform rod.For the rod with arbitrary variable cross-section, the conclusions are similar if the wave frequency is high enough.And a series solution of the wave motion is presented.
基金This work was supported by the National Natural Science Foundation of China under grant No.60274062.
文摘Surface acoustic wave (SAW) devices play a significant role in signal processing, frequency control and sensing applications. In general, they cannot operate at elevated temperature. The new crystal of langasite provides possibility for surface acoustic wave devices applied at high temperature. This paper studies the SAW properties of single and doubly rotated cuts of LGS at high temperature. The calculated SAW properties of LGS are analyzed in space with aid of contour plots, and two promising SAW orientation regions at high temperature are presented. For some typical cuts and propagating directions within the two optimal regions, their SAW characteristics vs temperature are discussed. Based on the experimental evidence in some literatures, the reliability of calculated results is verified.
基金supported by National Natural Science Foundation of China(Nos.50675050 and 50705023)Outstanding Youth Science Foundation of Hei-longjiang Province (No.JC200614)
文摘A multiscale simulation has been performed to determine the effect of the cutting speed on the deformation mechanism and cutting forces in nanometric cutting of single crystal copper. The multiscale simulation model, which links the finite element method and the molecular dynamics method, captures the atomistic mechanisms during nanometric cutting from the free surface without the computational cost of full atomistic simulations. Simulation results show the material deformation mechanism of single crystal copper greatly changes when the cutting speed exceeds the material static propagation speed of plastic wave. At such a high cutting speed, the average magnitudes of tangential and normal forces increase rapidly. In addition, the variation of strain energy of work material atoms in different cutting speeds is investigated.
文摘Results are presented for the 3D numerical simulation of the water impact of a wave energy converter in free fall and subsequent heave motion. The solver, AMAZON-3D, employs a Riemann-based finite volume method on a Cartesian cut cell mesh. The computational domain includes both air and water regions with the air/water boundary captured automatically as a discontinuity in the density field thereby admitting break up and recombination of the free surface. Temporal discretisation uses the artificial compressibility method and a dual time stepping strategy. Cartesian cut cells are used to provide a boundary-fitted grid at all times. The code is validated by experimental data including the free fall of a cone and free decay of a single Manchester Bobber component.
文摘The surface profile behavior of workpieces sawn has been investigated. Six species were sawn under the condi-tion of four different kinds of cutting speed by the band saw. The real surface profile of a sawn workpiecc is composed of twosections, which arc the additivity of the waviness of filtered wave and roughness curve. The roughness of center line avernge aswell as amplitude decrease with the increasing of cutting speed for different kinds of species used in the experiment.
文摘为探究适用于制作卤煮牛肉的超声频率及牛肉部位,以牛腱、牛霖和牛米龙为原料,分别在0、20、28和50 k Hz条件下进行超声处理,通过测定色泽、蒸煮损失率、质构特性、嫩度及风味物质等指标,结合主成分分析(PCA)与模糊数学感官评价法综合评估卤煮牛肉的品质。结果表明:超声辅助卤煮可显著改善各部位牛肉的色泽、保水性、质构特性及嫩度;GC-MS共鉴定出27种关键风味物质(OAV≥1);PCA分析显示,经20 k Hz超声处理的牛米龙所制得的卤煮牛肉综合品质最佳,该结果与模糊数学感官评价结果一致。研究为卤煮牛肉生产企业提供了科学、客观且具有较高应用价值的理论依据与技术参考,有助于提升产品品质和生产效率。
