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在索尼推出CDWalkman八年之后,又率先推出以数码方式录音的MiniDisc(以下简称MD),这一革命性的技术再次震动了业界,随后夏普、松下、建伍、JVC等厂商也逐渐加入到这个行业来。MDWalkman采用先进的数码数据压缩技术,只有CD唱片一半大小的64mm直径碟片却可以容纳长达74分钟的录音(现在已有80分钟的MD碟片)。它不仅体积小,而且还具有录放时间长、电脑编辑等功能。经过12年的发展,MD的编码方式已从传统的ATRAC变化到提高压缩率又实现高质量音效的ATRAC3,而LP4技术的开发也增加了MD碟片存储音乐的数量。但在当年所有的制造商都没有… 相似文献
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在此将VHDL语言设计的计数器应用于脉搏测量,精确的计量出脉搏跳动,并通过数码管直观地表示出来。显示出VHDL语言设计数字系统与医学的紧密联系及其在医疗实践中的巨大应用前景。实践证明,将EDA技术与医学相结合,不仅能促进EDA技术的深入发展,而且能够极大地推动医学的进步。 相似文献
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Effect of f-c hybridization on the $\gamma\to \alpha$ phase transition of cerium studied by lanthanum doping 下载免费PDF全文
Yong-Huan Wang 《中国物理 B》2022,31(8):87102-087102
The hybridization between the localized 4f level (f) with conduction (c) electrons in $\gamma $-Ce upon cooling has been previously revealed in single crystalline thin films experimentally and theoretically, whereas its influence on the $\gamma \to \alpha $ phase transition was not explicitly verified, due to the fact that the phase transition happened in the bulk-layer, leaving the surface in the $\gamma $ phase. Here in our work, we circumvent this issue by investigating the effect of alloying addition of La on Ce, by means of crystal structure, electronic transport and angle resolved photoemission spectroscopy measurements, together with a phenomenological periodic Anderson model and a modified Anderson impurity model. Our current researches indicate that the weakening of f-c hybridization is the major factor in the suppression of $\gamma \to \alpha $ phase transition by La doping. The consistency of our results with the effects of other rare earth and actinide alloying additions on the $\gamma \to \alpha $ phase transition of Ce is also discussed. Our work demonstrates the importance of the interaction between f and c electrons in understanding the unconventional phase transition in Ce, which is intuitive for further researches on other rare earth and actinide metals and alloys with similar phase transition behaviors. 相似文献
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Structure phase transformation and equation of state of cerium metal under pressures up to 51 GPa 下载免费PDF全文
This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high energy synchrotron x-ray source. The bulk moduli of high pressure phases of cerium are calculated using the Birch–Murnaghan equation. We discuss and correct several previous controversial conclusions, which are caused by the measurement accuracy or personal explanation. The c/a axial ratio of ε-Ce has a maximum value at about 29 GPa, i.e., c/a ≈ 1.690. 相似文献
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