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Power spectral properties of the soft spectral states in four black hole transients

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Research in Astronomy and Astrophysics 2021年第7期21卷 143-154页

作者： Dong-ming mao Wen-Fei Yu Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China

The X-ray variability in the soft X-ray spectral state of black hole binaries is primarily characterized by a power-law noise(PLN), which is thought to originate from the propagation of the modulation in the mass accretion rate of a standard accretion disk flow. Such a PLN has also been revealed in the disk spectral component in the hard and the intermediate states in several black hole binaries. Here we present an investigation of the Rossi X-ray Timing Explorer(RXTE) observations of four black hole transients in which soft spectral states were observed twenty times or more. We show that in the soft spectral state, the PLN index varied in a large range between –1.64 and –0.62, and the fractional rms variability calculated in the 0.01 – 20 Hz frequency range reached as large as 7.67% and as low as 0.83%. Remarkably,we have found evidence of an inclination dependence of the maximal fractional rms variability, the averaged fractional rms variability and the fractional rms variability of the median in the sample based on current knowledge of inclination of black hole binaries. An inclination dependence has only been predicted in early magnetohydrodynamic simulations of isothermal disks limited to a high-frequency regime. In theory,the noise index is related to the physics of inward propagation of disk fluctuations, while the fractional rms amplitude reflects the intrinsic properties of the magnetohydrodynamic nature of the accretion *** results therefore suggest that X-ray variability in the soft state can be used to put constraints on the properties of the accretion flow as well as the inclination of the accretion disk.

关键词： X-rays:general X-rays:binaries X-rays:individual:4U 1630-47 H 1743-322 XTE J1817-330 XTE J1859+226

Projective Lag Synchronization and Parameter Identification of a New Hyperchaotic System

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International Journal of Automation and computing 2013年第3期10卷 256-259页

作者： Wan-Li Guo ming-Zhi mao School of Mathematics and Physics China University of Geosciences

This work was supported by National Basic Research Program of China （973 program）（No. 2011CB710605）, TianYuan Special Funds of National Natural Science Foundation of China （No. 11226134）, National Natural Scien... 详细信息

关键词： Projective lag synchronization hyperchaotic system parameter identification Lyapunov stability theory LaSalle"s in-variance principle.

Preparation Process and Characteristics Analysis of Ni-Al System Intermetallic Compound Coatings

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材料热处理学报 2004年第05B期25卷 970-973页

作者： SUNHong-fei WANGCan-ming WANDian-mao JINTao SONGQiang MaterialResearchInstituteofShandongUniversityofScienceandTechnology TaianChina

Ni-Al system intermetallic compound coatings were acquired on the substrates of Nickel base superalloy by thermal spray accompanied with metallurgy and diffusion process. The main phases in the coatings are NiAl and Ni3Al and the microstructure oi" the coatings are dense. The coatings bond well with the substrates and show excellent characteristics of oxidation-resistance at temperature as high as 1300 °C. The coatings have been applied successfully in industry.

关键词：金属互化物高温扩散 Ni-Al合金预处理特征分析

Theoretical Analysis on Deflection and Bearing Capacity of Prestressed Bamboo-Steel Composite Beams

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Journal of Renewable Materials 2024年第1期12卷 149-166页

作者： Qifeng Shan ming mao Yushun Li School of Civil Engineering Zhejiang Industry Polytechnic CollegeShaoxing312000China School of Civil&Environmental Engineering and Geography Science Ningbo UniversityNingbo315211China College of Civil Engineering and Architecture Qingdao Agricultural UniversityQingdao266109China

A theoretical analysis of upward deflection and midspan deflection of prestressed bamboo-steel composite beams is presented in this *** deflection analysis considers the influences of interface slippage and shear ***,the calculation model for flexural capacity is proposed considering the two stages of *** theoretical results are verified with 8 specimens considering different prestressed load levels,load schemes,and prestress *** results indicate that the proposed theoretical analysis provides a feasible prediction of the deflection and bearing capacity of bamboo-steel composite *** deflection analysis,the method considering the slippage and shear deformation provides better *** theoretical method for bearing capacity matches well with the test results,and the relative errors in the serviceability limit state and ultimate limit state are 4.95%and 5.85%,respectively,which meet the accuracy requirements of the engineered application.

关键词： Bamboo scrimber composite beam prestress deflection bearing capacity

Polycarbonate/Polypropylene/Fibrillar Silicate Ternary Nanocomposites: Morphology and Mechanical Properties

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Journal of Materials Science & Technology 2006年第1期22卷 87-92页

作者： Xiang GAO Lixin mao ming TIAN Liqun ZHANG Riguang JIN College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

Polycarbonate （pc）/polypropylene （pp）/silicate attapulgite （AT） ternary nanocomposites were first prepared via the two-step melt blending process. Phase structure of the ternary composites was characterized by transmission electron microscopy （TEM） and dynamic mechanical analysis （DMA）, in which the morphology of encapsulation of AT by PP in the PC matrix were observed. The mechanical properties of the ternary composites were investigated using the tensile tester and Izod impact tester. The results show that encapsulation of AT by PP in PC enhances the toughness of the matrix effectively and give the best tensile and impact strength.

关键词： Polycarbonate Polypropylene Attapulgite Morphology Property

Chemical composition and structural identification of primary carbides in as-cast H13 steel

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International Journal of Minerals,Metallurgy and Materials 2019年第7期26卷 839-848页

作者： ming-tao mao Han-jie Guo Fei Wang Xiao-lin Sun School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing 100083 China Central Iron & Steel Research Institute Beijing 100081 China

The aim of this study was to characterize the primary carbides formed in as-cast H13 steel. The composition, morphology, type, and size of primary carbides in as-cast H13 steel were investigated by optical microscope (OM), field emission scanning electron microscopy (FE-SEM), electron back-scattered diffraction (EBSD), and X-ray diffraction (XRD) analysis. The number of primary carbides was investigated by ASPEX automated inclusion analysis system. The results indicated that primary carbides in as-cast H13 steel are mainly composed of Cr, Mo, V, and Ti, and there exist four kinds of primary carbides in the interdendritic zones of H13 steel, which are stripy Mo–Cr-rich M2C, eutectic Mo–Cr-rich M2C, V-rich MC, and V-rich MC with Ti and N. Thermodynamic calculation indicated that M2C precipitates in liquid phase at solid fractions larger than 0.99, while MC precipitates in liquid phase at solid fractions larger than 0.96. Statistical results indicated that the number of M2C is much greater than the number of other kinds of primary carbides. Most primary carbides are blocky, with lengths of no more than 10 μm and a length/width ratio of no more than 3. The large primary carbides in as-cast H13 steel are mainly M2C.

关键词： primary carbide phase identification H13 steel precipitation thermodynamic

Design, Synthesis and Structure-activity of N-Glycosyl-l-pyridyl-lH-pyrazole-5-carboxamide as Inhibitors of Calcium Channels

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Chemical Research in Chinese Universities 2013年第2期29卷 249-255页

作者： ZHOU Yun-yun LI Yu-xin LI Yi-ming YANG Xiao-ping mao ming-zhen LI Zheng-ming State Key Laboratory of Elemento-Organic Chemistry Institute of Elemento-Organic Chemistry Nankai University Tianjin 300071 P. R. China School of Pharmacy University of Wyoming Laramie WY 82071 USA

Carbohydrates, with broad-spectrum structures and biological functions, are key organic compounds in nature, along with nucleic acids and proteins. As part of our ongoing efforts to develop a new class of pesticides with novel mechanism of action, a series of novel N-glycosyl-l-pyridyl-lH-pyrazole-5-carboxamide was designed and synthesized via the reactions of glycosyl methanamides and pyridyl-pyrazole acid. The compounds were characte- rized by IH NMR and 13C NMR. The bioassay results indicate that some of these compounds exhibit moderate insec- ticidal activities and assessed as potential inhibitors of calcium channels. The modulation of voltage-gated calcium channels by compounds 4a and 5a in the central neurons isolated from the third instar larvae of Spodoptera exigua was studied by whole-cell patch-clamp technique. In addition, compound 5a inhibits the recorded calcium currents reversible on washout. Experimental results also indicate that compound 5a did not release stored calcium from the Endoplasmic Reticulum. The present work demonstrates that N-glycosyl-l-pyridyl-lH-pyrazole-5-carboxamides cannot be used as possible inhibitors of calcium channels for developing novel pesticides.

关键词： N-Glycosyl Pyridyl Pyrazole Insecticidal activity Calcium channel

Machine learning method to predict dynamic compressive response of concrete-like material at high strain rates

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Defence Technology（防务技术） 2023年第5期23卷 100-111页

作者： Xu Long ming-hui mao Tian-xiong Su Yu-tai Su Meng-ke Tian School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'anChina School of Civil Engineering Liaoning Petrochemical UniversityFushunChina Beijing Microelectronics Technology Institute BeijingChina

Machine learning(ML)methods with good applicability to complex and highly nonlinear sequences have been attracting much attention in recent years for predictions of complicated mechanical properties of various *** one of the widely known ML methods,back-propagation(BP)neural networks with and without optimization by genetic algorithm(GA)are also established for comparisons of time cost and prediction *** the aim to further increase the prediction accuracy and efficiency,this paper proposes a long short-term memory(LSTM)networks model to predict the dynamic compressive performance of concrete-like materials at high strain *** explicit analysis is performed in the finite element(FE)software ABAQUS to simulate various waveforms in the split Hopkinson pressure bar(SHPB)experiments by applying different stress waves in the incident *** FE simulation accuracy is validated against SHPB experimental results from the viewpoint of dynamic increase *** order to cover more extensive loading scenarios,60 sets of FE simulations are conducted in this paper to generate three kinds of waveforms in the incident and transmission bars of SHPB *** training the proposed three networks,the nonlinear mapping relations can be reasonably established between incident,reflect,and transmission *** measures are used to quantify the network prediction accuracy,confirming that the predicted stress-strain curves of concrete-like materials at high strain rates by the proposed networks agree sufficiently with those by FE *** is found that compared with BP network,the GA-BP network can effectively stabilize the network structure,indicating that the GA optimization improves the prediction accuracy of the SHPB dynamic responses by performing the crossover and mutation operations of weights and thresholds in the original BP *** eliminating the long-time dependencies,the proposed LSTM network achieves better results than the BP

关键词： Deep learning LSTM network GA-BP network Dynamic behaviour Concrete-like materials

Fe Kα line profile in AGNs: average shape and redshift dependence

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Research in Astronomy and Astrophysics 2010年第9期10卷 905-914页

作者： Wei-ming mao Chen Hu Jian-Min Wang Gang Zhao Shu Zhang Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

We collect a sample of 381 （271 type Ⅰ） active galactic nuclei （AGNs） with XMM-Newton observations for an analysis of the dependence of Fe Kα profiles on redshifts to test the potential cosmological evolution of spins of supermassive black holes （SMBHs）. The sample spans a redshift range of z = 0.0008 - 4.76, which allows us to rebin the sample into 7 redshift groups. Phenomenological analysis of the Fe profile suggested that the line width （δ） of the narrow or broad Fe line does not show significant changes in redshift range z 〈 0.3. Using a physical model, we significantly detect a narrow Fe Kα line at 6.4 keV with an average equivalent width （EW） = 160 eV except for the two largest redshift bins. The EW of the Fe line does not show significant changes. We also find a relativistic broad line in three redshift bins （z 〈 0.116, 0.056 〈 z 〈 0.12 and 0.12 〈 z 〈 0.3）with an average EW = 522eV.

关键词： galaxies active -- X-rays general -- methods data analysis