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	The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition 期刊论文 OAI收割 Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 494, 页码: 1865-1870 作者: HXMT \| 收藏 \| 浏览/下载：57/0 \| 提交时间：2022/02/08 stars: magnetic field stars: neutron pulsars: general Astrophysics - High Energy Astrophysical Phenomena Abstract: In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540-69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540-69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.
	Study on sub-pixel techniques for accurate image measurement of displacement (EI CONFERENCE) 会议论文 OAI收割 2011 2nd International Conference on Advanced Measurement and Test, AMT 2011, June 24, 2011 - June 26, 2011, Nanchang, China 作者: Zhang X.; Zhang X.; Zhang X. 收藏 \| 浏览/下载：17/0 \| 提交时间：2013/03/25 The high resolving power camera was often used to improve the precision of measuring system although its price is high because the accuracy of image measure was limited by the pixel resolving ability of camera. A method of one dimension gray level quadrature sub-pixel to detect edge was presented. This method was applied to measure the displacement of measuring head on 3-coordinate measuring machine. The data of test was shown that this system can distinguish displacement 0.001mm. it is higher accuracy than pixel level. So this method is convenient and fast fit to track and measure the moving object. It is obvious that this method can save the cost of hardware.
	Study on CCD image compression and mass storage (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China 作者: Liu H.; Liu H.; Liu H. 收藏 \| 浏览/下载：30/0 \| 提交时间：2013/03/25 When CCD camera photographs massive images in the air it is very important to compress and save CCD image timely and validly. This paper designs the CCD image compression and mass storage system. The one part is image compression: this paper introduces a reduced memory still image compression algorithm based on Listless Zerotree Coding (LZC). Compared with SPIHT the approach significantly reduced memory requirement and no reducing the quality of the reconstructed image. The other part is image mass storage: this system uses a kind of special hard disk storage devices that can realize faster data transmission to SCSI (Small Computer System Interface) devices even if it separates oneself from PCs. In the faster data acquisition and storage system data storage is a key technology. Normal approach is saving the data to mass memories and then processing and saving the data after complete acquisition. The continuous acquisition time is restricted with the storage capacity in the normal method so that it can't receive the requirement of CCD image storage on many occasions. While its price will be geminate increasing when we increase the storage capacity. So the approach in this paper is better one to use fast disks on data direct mass storage considering the storage capacity read/write speed and unit cost. The result of the experiment shows that the system has compressed and saved CCD image validly so it reached the anticipative purpose.
	Identifying the inter-market relationships of forest products in the Pacific Northwest with cointegration and causality tests SCI/SSCI论文 OAI收割 2003 Yin R. S.; Xu J. T. 收藏 \| 浏览/下载：23/0 \| 提交时间：2012/06/08 inter-market relationship cointegration causality weak exogeneity price forecasting united-states one price softwood lumber law imports