为了表现海浪的真实感和实时性仿真,本文以Pierson-Moskowitz模型为基础,采用波的波长和波速建立了海浪波高的初始状态值.通过FBM(Fractal Brown Motion)的菱形网格方式计算海浪曲面片上每个网格点的波高,把每个点画出;再以菱形网格模...为了表现海浪的真实感和实时性仿真,本文以Pierson-Moskowitz模型为基础,采用波的波长和波速建立了海浪波高的初始状态值.通过FBM(Fractal Brown Motion)的菱形网格方式计算海浪曲面片上每个网格点的波高,把每个点画出;再以菱形网格模拟海浪形状,将海浪点的波高描述为随时间和空间变化的多个正弦波叠加近似地表现海浪的运动效果;利用光照模型给海浪添加明暗凹凸效果,增加海浪的真实感;将真实世界中某一海浪的图像作为纹理源,贴到每个网格上,提高仿真的逼真度和运行速度,达到实时仿真的效果.利用Java和JOGL编程模拟,逼真地生成了海浪在不同风向、不同等级情况下的场景.实验表明文中所述方法得当,技术可行.展开更多
The objective of this paper is to introduce an appropriate unidirectional wave spectrum model for the Strait of Hormuz. The research is focused on assessing performance of standard wave spectrum models in the region. ...The objective of this paper is to introduce an appropriate unidirectional wave spectrum model for the Strait of Hormuz. The research is focused on assessing performance of standard wave spectrum models in the region. By evaluating such models based on valuable measurement data recently published, the calibration procedure has been conducted on such standard models to reach a better concordance between a modified standard spectral model and observed field spectra. The calibration is performed initially with respect to four distinct directions related to four available measurement stations. So, it results in four sets of coefficients for a nominated model. Next, it is continued to reach just one model insensitive to directions. Results clearly showed that the International Towing Tank Conference （ITTC） model is more appropriate than Joint North Sea Wave Project （JONSWAP） and Pierson and Moskowitz （PM） models in this area, even without any calibration. However, modifications have been successful on improving the conformity of the model.展开更多
The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials...The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Its δ-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity and δ-ratio (1.5), due to increasing three-dimensional magnetostatic interactions and collapse of magneto-some chains. These observations provide useful insights into applications of the biogenic magnetite (magnetosomes) in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.展开更多
文摘为了表现海浪的真实感和实时性仿真,本文以Pierson-Moskowitz模型为基础,采用波的波长和波速建立了海浪波高的初始状态值.通过FBM(Fractal Brown Motion)的菱形网格方式计算海浪曲面片上每个网格点的波高,把每个点画出;再以菱形网格模拟海浪形状,将海浪点的波高描述为随时间和空间变化的多个正弦波叠加近似地表现海浪的运动效果;利用光照模型给海浪添加明暗凹凸效果,增加海浪的真实感;将真实世界中某一海浪的图像作为纹理源,贴到每个网格上,提高仿真的逼真度和运行速度,达到实时仿真的效果.利用Java和JOGL编程模拟,逼真地生成了海浪在不同风向、不同等级情况下的场景.实验表明文中所述方法得当,技术可行.
文摘The objective of this paper is to introduce an appropriate unidirectional wave spectrum model for the Strait of Hormuz. The research is focused on assessing performance of standard wave spectrum models in the region. By evaluating such models based on valuable measurement data recently published, the calibration procedure has been conducted on such standard models to reach a better concordance between a modified standard spectral model and observed field spectra. The calibration is performed initially with respect to four distinct directions related to four available measurement stations. So, it results in four sets of coefficients for a nominated model. Next, it is continued to reach just one model insensitive to directions. Results clearly showed that the International Towing Tank Conference （ITTC） model is more appropriate than Joint North Sea Wave Project （JONSWAP） and Pierson and Moskowitz （PM） models in this area, even without any calibration. However, modifications have been successful on improving the conformity of the model.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40821091 and 40325011)Hundred Talents Program of the Chi-nese Academy of Sciences and Marie-Curie Fellowship (IIF) Return Phase of (Grant No. MIF1-CT-2005-007555)
文摘The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment, as well as novel nano-biomaterials in biotechnological and biomedical applications. We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes. Results revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental chain. The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction. For the whole cells, the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles. Its δ-ratio is 3.0 and passes the Moskowitz test. In contrast, the isolated magnetosome sample has reduced values of coercivity and δ-ratio (1.5), due to increasing three-dimensional magnetostatic interactions and collapse of magneto-some chains. These observations provide useful insights into applications of the biogenic magnetite (magnetosomes) in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.
