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991.
A theoretical model for surface bone remodeling under electromagnetic loads is proposed in this paper. In the model, surface
bone remodeling is assumed to be related to growth factors. Growth factors in latent form in osteocytes are released to the
bone fluid after the osteocytes are absorbed by osteoclasts, and then regulate the bone formation process. At the same time,
environmental loadings can influence the generation of growth factors. This paper shows how surface bone remodeling is triggered
under the influence of growth factors. Based on this hypothesis, a computational model is established that simulates the bone
coupling remodeling process, including internal and surface bone remodeling. The effects of various loadings, including electrical
and magnetic loadings, are simulated and compared. The interactions between internal and surface bone remodeling are investigated
via the numerical method. The results indicate that an electromagnetic field can strongly influence the bone remodeling process
and that the remodeling process will be altered after surface bone remodeling is triggered, compared to the sole effect of
the internal remodeling process. 相似文献
992.
多孔有限大弹性薄板弯曲应力集中问题 总被引:3,自引:0,他引:3
应用弹性力学的复变函数理论,采用多保角变换的方法,推出了含有任意多孔有限大弹性薄板弯曲的多复变量应力函数的表达式.在内边界上进行复Fourier级数展开,在外边界采用配点法来确定应力函数的未知系数,从而计算有限大弹性薄板的应力场.本文以外边界为矩形,内边界为任意多椭圆孔的有限薄板为例,编制了相应的计算程序,进行了算例分析.结果表明本方法对处理多孔有限大弹性平面问题是简单且行之有效的. 相似文献
993.
建立了动物饲料中竹桃霉素、红霉素、吉他霉素、交沙霉素、罗红霉素、泰乐菌素6种大环内酯和林可霉素、克林霉素2种林可胺抗生素的超高效液相色谱-电喷雾串联质谱(UPLC-ESI-MS/MS)检测方法。饲料样品采用甲醇提取,Oasis HLB固相萃取柱富集净化,Waters Acquity UPLC BEH C18色谱柱分离,以0.1%甲酸和乙腈为流动相进行梯度洗脱,流速为0.3 mL/min,正离子模式扫描,多反应监测模式检测,外标法定量。实验结果表明,8种药物在1~100 μg/L范围内具有良好的线性关系。在空白饲料样品中分别添加1、10和100 μg/kg 3个加标水平的8种药物,其平均回收率为68.6%~95.2%,相对标准偏差(RSD)为4.9%~11.8%,定量限均为1 μg/kg。结果表明,该方法简便快速、灵敏度高,适用于动物饲料中大环内酯类和林可胺类抗生素的同时检测。 相似文献
994.
Bin-ping Zhuang Fa-chun Lai Li-mei Lin Ming-bao Lin Yan Qu Zhi-gao Huang 《化学物理学报(中文版)》2010,23(1):79-83
ZnO nanobelts, hollow microspheres, and urchins have been prepared on copper foil via a simply low temperature evaporation route. The microstructure, morphologies, and photolu-minescence of the ZnO nanostructures were studied with X-ray diffraction, Raman spectra, scanning electron microscopy and photoluminescence spectra. The width of the nanobelts was about 500 nm and the length was longer than 10μm. The diameter of the hollow microspheres was between 5 and 10μm. A possible growth mechanism of the nanobelts, microspheres and urchins was proposed. The photoluminescence spectrum exhibited strong deep level energy emissions and a weak near band edge emission. These ZnO nanostructures on a copper substrate have the advantages of naturally good adhesion and electrical connection between the ZnO nanostructures and the conductive substrate. 相似文献
995.
Yunxiaing You Tianqun Hu Hao Xu Yongliu Fang Zhong Yu Zhongmin Shi Yan Qu Yue Xiao 《力学学报》2010,42(3):400
对密度分层流体中内波与半潜平台的相互作用问题
进行了模型试验研究. 采用摇板方法进行了内波造波试验,对内波波长、周期和波高进行了
测量分析,获得了内波波高和波长与周期之间的相关关系. 利用激光和倾角仪方法对半潜平
台的纵荡和纵摇运动响应进行了测量分析,获得了平台纵荡运动及纵摇角幅值与内波周期之
间的相关关系. 结果表明,在半潜平台的设计与应用中,内波对其运动响应的影响是不可忽
视的. 特别地,发现了在内波周期的某个范围内, 半潜平台的纵荡和纵摇都会出现
倍频周期运动响应的现象. 相似文献
996.
In this paper, a chaos system and proportional
differential control are both used to detect the frequency of an
unknown signal. In traditional methods the useful signal is obtained
through the Duffing equation or other chaotic oscillators. But these
methods are too complex because of using a lot of chaos oscillators.
In this paper a new method is presented that uses the R?ssler
equation and proportional differential control to detect a weak
signal frequency. Substituting the detected signal frequency into
the R?ssler equation leads the R?ssler phase state to be
considerably changed. The chaos state can be controlled through the
proportional differential method. Through its phase diagram and
spectrum analysis, the unknown frequency is obtained. The simulation
results verify that the presented method is feasible and that the
detection accuracy is higher than those of other methods. 相似文献
997.
Effect of noise on erosion of safe basin in power system 总被引:1,自引:0,他引:1
We study the effect of Gaussian white noise on erosion of safe basin in a simple model of power system whose safe basin is
integral in the absence of noise. The stochastic Melnikov method is first applied to predict the onset of basin erosion when
the noise excitation is present in system. And then the eroded basins are simulated according to the necessary restrictions
for the system’s parameters. It is found that for the noisy power system when the noise intensity σ is greater than a threshold, basin erosion occurs and as σ is further increased basin erosion is aggravated. These studies imply that random noise excitation can induce and enhance
the basin erosion in the power system. 相似文献
998.
用一种基激复合物荧光探针系统来签别碱基错配的CYP2C9*3基因,该系统选择两个分开的与靶点碱基相对应的12碱基荧光标记的寡核苷酸作为探针,分别对24碱基、47碱基、质粒(3165bp)的靶点CYP2C9基因和CYP2C9*3基因进行杂交配对,结果该基激复合物荧光探针系统能有效签别各种长度的CYP2C9基因和CYP2C9*3基因,背景干扰很低,灵敏度高,可尝试用于其他基因型的遗传多态性的签别。 相似文献
999.
1000.
Fanyao Qu N. O. Dantas P. C. Morais 《Physica E: Low-dimensional Systems and Nanostructures》2001,9(4):709
The investigation of the evolution of the photoluminescence spectra, in single asymmetric quantum wells (SAQWs), from a typical emission spectrum to a Fermi-edge singularity, is carried out as a function of both the optical excitation intensity and the temperature. The three samples used here are n-doped, low carrier density (below 5×1011 cm−2), GaAs/Al0.35Ga0.65As SAQWs grown by molecular beam epitaxy. The strong collective recombination of electrons with different k states up to the Fermi wave vector as well as the optical signature of the Fermi-edge singularity is observed in two samples containing residual acceptors inside the GaAs SAQW. In contrast, a third sample containing no experimental evidence of residual acceptors in the GaAs SAQW shows no optical signature of the Fermi-edge singularity. 相似文献