中国科学院机构知识库网格系统: 检索

Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2020, 卷号: 27, 页码: 51-52
作者: HXMT

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Astrophysics - High Energy Astrophysical Phenomena Abstract: Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in X-rays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. This allows, in particular, to observe bright sources like X-ray binaries (XRBs) in their bright/outburst states with high cadence and high statistics at hard and soft X-rays at once. It was then expected that the Insight-HXMT mission will bring us new insights regarding the characteristics of several source classes. Examples include characterizing High-Mass X-ray Binaries (HMXBs) and the outburst evolution of Low-Mass X-ray Binaries (LMXBs). For instance, in HMXB systems, the region around their Alfven radius that is responsible to determine whether accretion or propeller occurs, or the region around the NS magnetic pole where the intense X-rays are supposed to be produced are specially appealing targets of study. For the LMXBs, the evolution the outburst and the properties of the compact objects themselves are obvious priority targets for Insight-HXMT. Due to the broad coverage in energy, Insight-HXMT is specially well suited to study the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environment.

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

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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.

Effect of Zn doping on the hydrogenolysis of glycerol over ZnNiAl catalyst 期刊论文 OAI收割
journal of molecular catalysis a-chemical, 2014, 卷号: 395, 页码: 1-6
Li, Xiaoru; Zhang, Chao; Cheng, Haiyang; He,Limin; Lin,Weiwei; Yu,Yancun; Zhao,Fengyu

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Nickel based catalyst is of interest in the industrial catalytic processes and it is always modified by doping a second element to improve its catalytic properties. Understanding the role of dopant is extremely helpful in tailoring the active centers. In this work Zn could induce a significant improvement of the catalytic performance of NiAl for the hydrogenolysis of glycerol. The Zn doped ZnNiAl catalysts exhibited high activity and the improved selectivity to 1 2-propanediol it was about 2 times higher than the original ones. The ZnNi alloy formed in ZnNiAl was responsible for the noticeable catalytic performance. They preferred to coordinate with the end hydroxyl group of glycerol promoted the cleavage of C-O bond in glycerol and resulted in the dominant formation of 1 2-propanediol. The findings described here will provide a useful knowledge for rational design of nickel-based catalysts as well as reveal a new reaction model for the hydrogenolysis of glycerol. (C) 2014 Elsevier B.V. All rights reserved.

Effect of design parameters on the reduction of top piston ring friction (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Computer-Aided Design, Manufacturing, Modeling and Simulation, CDMMS 2012, September 21, 2012 - September 23, 2012, Chongqing, China
作者: Wang P.

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In order to reduce ring-liner interface friction power loss this paper focuses on the structure parameters of the top ring and investigates how the value of those parameters will influence top ring-liner friction power loss and the minimum thickness of oil film at top ring-liner interface. A mixed lubrication model is developed to simulate the effect of varying design parameters on ring-liner friction. Case study shows that ring-liner friction power loss will be reduced with decreased axial ring height and barrel height. This study provides a theoretical basis for design the top ring with reduced friction power loss at ring-liner interface. (2013) Trans Tech Publications Switzerland.

STEP Mission: Search for Terrestrial Exo-Planets 会议论文 OAI收割
European Planetary Science Congress 2013,, London, UK, 2013
Chen D.; Wu; J.; Li B.

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Search for Terrestrial Exo-Planest (hereafter STEP) mission is a latest advanced research project in Chinese Strategic Pioneer Program (SPP) on Space Science. STEP aims at the nearby earth-alike planets detection comprehensive research on the planetary system and some astrometry research with 0.5 uas precision in the space which will get the fruitful achievements in the exo-planetary and astrometry research fields. STEP will take the Space Astrometry technique in the optical band. The FOV is 0.44 degree based on 1.2m primary and focus length is 50m. The special metrology technique will be taken to reach 0.5 uas astrometry precision which will be idea for terrestrial exo-planets detection. The mission will take the L2 orbit.

Macroeconomic impacts of Chinese currency appreciation on China and the Rest of World: A global CGE analysis SCI/SSCI论文 OAI收割
2013
作者: Yang J.

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Exchange rate Economic impacts General equilibrium model exchange-rate renminbi undervaluation policy model will

Research on load-bearing characteristics of precision air-bearing rotary stage (EI CONFERENCE) 会议论文 OAI收割
3rd international Conference on Manufacturing Science and Engineering, ICMSE 2012, March 27, 2012 - March 29, 2012, Xiamen, China
作者: Wang L.; Wang L.; Wang L.; Lin J.

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Air-bearing is a core component of air-bearing rotary stage. The weakness that the air-bearing has the low load capacity and stiffness has been concerned about by domestic and foreign scholars. So how to improve the load capacity and stiffness has become a serious problem. In order to improve the load capacity and stiffness of the air-bearing rotary stage in this paper we improved structure of Zhang Wenjie and others' high-precision direct-drive air-bearing rotary stage. The gas film of air-bearing has been meshed by GAMBIT software and we use FLUENT software to obtain the carrying capacity features of the gas film. Finally the structural static force of the precision air-bearing rotary stage will be analyzed by ANSYS software. The analysis results show that: the structural design of the precision air-bearing rotary stage is reasonable and this structure can provide a larger range of loads. Even in heavy load conditions a larger deformation will not occur any more. It has a good practical value and also can be widely used in high precision equipments. (2012) Trans Tech Publications.

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

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The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

Correction of baseline drifts due to the pressure changes between attenuated total reflection prism and human skin for noninvasive blood glucose sensing with Fourier Transform infrared spectroscopy (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Smart Materials and Nanotechnology in Engineering, SMNE 2011, September 17, 2011 - September 18, 2011, Wuhan, China
作者: Wang D.

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For noninvasive blood sensing with attenuated total reflection (ATR)-Fourier Transform infrared spectroscopy(FTIR) the baseline of spectra human skin will drift because of the exitence of pressure changes between ATR prism and human skin. To correct the baseline drifts In the paper the fingertips spectra in mid-infrared were recorded under the special conditions. A line equation was calculated using the last 14 spectra coupled with the linear regression analysis between the absorbance spectra at the 1035cm-1 and the 950cm-1. And the corrected absorption intensities after the removal of the baseline drifts can be applied for the quantification of glucose concentrations in blood easily with the given method in the paper. (2012) Trans Tech Publications Switzerland.

A new low-bandwidth and wireless transmission scheme for CCd image (EI CONFERENCE) 会议论文 OAI收割
2012 International Symposium on Photonics and Optoelectronics, SOPO 2012, May 21, 2012 - May 23, 2012, Shanghai, China
作者: Zhang Y.

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The CCD (Charge-coupled Device) image sensor with its high resolution is capable of providing high definition image. However transmission requires high bandwidth which makes it very difficult to process and transmit in a long distance. The purpose of this paper is to propose a new method to process and transmit CCD image which can guarantee a low-bandwidth and long-distance data transmission. The innovation is that the transmission content of CCD image data can be flexibly selected and compressed firstly which will reduce the transmission data. Then it is processed on the base of communication protocol so that it can be fit for wireless transmission. At last it is transformed into wireless signal and transmitted using 3G technology. As a result the paper presents a wireless transmission scheme with the rate of 1.5Mbps for CCD image. 2012 IEEE.