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51.
APS单反相机在1997年问世,APS表现出优良的画面质量,使得消费者在对它冷落一段时间之后不得不进行重新评价。另外,提出了APS在中国所遇到问题,如缺少冲扩店,胶卷价格贵等。 相似文献
52.
He N Wang T Jiang L Wang D Hu Y Zhang L 《Journal of nanoscience and nanotechnology》2010,10(8):5320-5323
In this study we prepared nanocarrier of erythropoietin (EPO) and the curative effect of the EPO-containing nanoparticles for periventricular leukomalacia (PVL) model was validated. It was demonstrated that EPO-containing nanoparticles can ameliorate drug-induced liquefaction caused by hypoxia. EPO-containing nanomedicine may open new therapeutic strategies in hypoxia cure. 相似文献
53.
Background The accelerator-driven subcritical transmuta-tion system(ADS)is an advanced technology for the harmless disposal of nuclear waste.A theoretical analy... 相似文献
54.
Based on the simplified planar quadruped model with a passive spine joint, this paper focuses on studying the effect of the spine joint on the dynamic performance and the stability of the rotary galloping gait. The stable, periodic, and symmetric rotary galloping gait is achieved by the particle swarm optimization method without any parameter symmetry for leg motion and without any limitation for spine motion. By analyzing the symmetric pattern of the rotary galloping gait, the stability criterion is derived: the closer to zero is the pitching angle at peak time of the center of mass, the better is the stability of the galloping gait. Then, we study the effect of rear leg touchdown angle and spine stiffness on the stability. Moreover, the unstable rotary galloping gait can be stabilized by adjusting one or more of the touchdown angle, spine stiffness, and leg stiffness. Furthermore, the effect of the spine stiffness on the key kinematic and kinetic properties is also studied for different initial values and mechanical parameters. The presented stability criterion and the achieved dynamic performance analysis results will be instructive for the design and control of the quadruped robot. 相似文献
55.
Zedong Zhao Minqiang Sun Tianqi Wu Jiajia Zhang Peng Wang Long Zhang Chongyang Yang Chengxin Peng Hongbin Lu 《纳微快报(英文)》2021,(8):40-55
Lithium- and manganese-rich (LMR) layered cath-ode materials hold the great promise in designing the next-genera-tion high energy density lithium ion batteries.... 相似文献
56.
通过对印度“丝绸标志”和中国“高档丝绸标志”在组织形式、推广内容、方式、方法等方面的比较研究,提出了改进我国“高档丝绸标志”推介的建议,强调为了提高我国“高档丝绸标志”在国际丝绸市场上的公信度,必须加强在“高档丝绸标志”推广工作中经费、人才等方面的投入,加强丝绸界与蚕桑界的合作,共同促进“高档丝绸标志”的使用。 相似文献
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Automatic detection and validity of the sea-ice edge: an application of enhanced-resolution QuikScat/SeaWinds data 总被引:1,自引:0,他引:1
Haarpaintner J. Tonboe R.T. Long D.G. Van Woert M.L. 《Geoscience and Remote Sensing, IEEE Transactions on》2004,42(7):1433-1443
Sea-ice edge detection is an essential task at the different national ice services to secure navigation in ice-covered seas. Comparison between the Remund and Long ice mask image from enhanced-resolution QuikScat/SeaWinds (QS) products and the analyzed ice edge from high-resolution RADARSAT synthetic aperture radar has shown that the automatically determined QS ice mask underestimates the Arctic ice extent. QS data was statistically analyzed by colocating the data with ice charts around Greenland and with the National Aeronautics and Space Administration Team's Special Sensor Microwave/Imager (SSM/I) ice concentration algorithm over the whole Arctic region. All variables, i.e., the backscatter in vertical and horizontal polarization, the active polarization ratio (APR) and the daily standard deviation, are sensitive to ice types and are strongly correlated with ice concentration when the relationship is expressed in exponential form. Our study showed that the APR is especially suitable for ice-ocean separation, and a threshold of -0.02 was determined. An ice edge algorithm based on this APR threshold was developed using the other variables with conservative season-dependent thresholds to eliminate additional ocean noise. Also, the history of the ice cover is considered in order to detect single ice fields that are separated from the main Arctic pack ice. Validation with RADARSAT 1 and with the Advanced Very High Resolution Radiometer showed that the new algorithm successfully detects very low ice concentrations of about 10% during the entire year. The validity of the detected ice edge for near-real-time issues is also discussed in relation to the ice motion in the Marginal Ice Zone and the integration time necessary to produce the enhanced-resolution images. The new algorithm improves the automatic global ice edge resolution by a factor of two when compared to SSM/I products and could be used in both model initialization and data assimilation. 相似文献