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Constraining the anisotropy of the Universe with the Pantheon supernovae sample

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Chinese Physics C 2019年第12期43卷 180-187页

作者： zhe chang Dong Zhao Yong Zhou Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We test the possible dipole anisotropy of the Finslerian cosmological model and the other three dipolemodulated cosmological models,*** dipole-modulated ACDM,wCDM and Chevallier-Polarski-Linder(CPL)models,by using the recently released Pantheon sample of SNe *** Markov chain Monte Garlo(MGMC)method is used to explore the whole parameter *** find that the dipole anisotropy is very weak in all cosmological models *** the dipole amplitudes of four cosmological models are consistent with zero within the 1σuncertainty,the dipole directions are close to the axial direction of the plane of the SDSS subsample in *** may imply that the weak dipole anisotropy in the Pantheon sample originates from the inhomogeneous distribution of the SDSS subsample.A more homogeneous distribution of SNe la is necessary to constrain the cosmic anisotropy.

关键词： supernovae:general large-scale structure of the Universe cosmology

High Sensitivity Biomolecular Recognition Device Based on Giant Magnetoresistance Effect

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稀有金属材料与工程 2006年第A3期35卷 522-524页

作者： Ming Wang chang-zhe Wu Tao Song Department of Medical Engineering Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100080 China

The structure and microfabrication,the detecting theory and the way of biomolecular recognition device based on giant magnetoresistance(GMR) effect are introduced,also the signal detecting and processing instrumentation are presented. Here the GMR biosensor was fabricated with magnetic tunnel junction(MJT) *** biomolecular recognition device contains an array of MJT sensors,single MJT sensor size is 10μm×20μm,tunneling magnetoresistance ratio(TMR) at room temperature is 52.2%,the typical values of junction resistance-area product Rs is 2.6 kΩμm^2,detecting sensitivity of this system is about 8×10^(-4) A·m^(-1).Bioadaptation layer of this device was fabricated with PDMS the thickness of which is less than 100 nm.

关键词： giant magnetoresistance(GMR) magnetic tunnel junction(MJT) tunneling magnetoresistance ratio(TMR)

Propagation effect of gravitational wave on detector response

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Science China(Physics,Mechanics & Astronomy) 2016年第10期59卷 81-84页

作者： zhe chang Chao-Guang Huang Zhi-Chao Zhao Institute of High Energy Physics and Theoretical Physics Center for Science Facilities Chinese Academy of Sciences

Dear Editors,The detection of gravitational waves（GW）in the event GW150914 by the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory（LIGO）[1]opens a new era for the direct detection of GW[2],searching black hole coalescence[3]and‘heavy’black holes with more than25 solar mass[4],test of general relativity[5],understanding the astrophysical environment of black hole formation[6],*** one words,

关键词：探测器引力波传播效应广义相对论激光干涉直接检测太阳质量物理环境

Note on gauge invariance of second order cosmological perturbations

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Chinese Physics C 2021年第9期45卷 188-210页

作者： zhe chang Sai Wang Qing-Hua Zhu Theoretical Physics Division Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We study the gauge invariant cosmological perturbations up to the second *** demonstrate that there are infinite families of gauge inv ariant variables at both the first and seco nd *** conversion formulae among different families are verified to be described by a finite number of bases that are gauge *** the second order cosmological perturbations induced by the first order scalar perturbations,we explicitly represent their equations of motion in terms of the gauge invariant Newtonian,synchronous and hybrid variables,respectively.

关键词： cosmological perturbation theory physics of the early universe gauge invariance

基于Super-Twisting滑模S面的无人机路径跟踪控制

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火力与指挥控制 2024年第2期49卷 11-17页

作者：张国兵石上瑶李佳成常哲陈鹏云中北大学航空宇航学院太原030051

针对小型固定翼无人机在执行任务时跟踪精度低以及容易受外界风影响的问题,设计基于Super-Twisting滑模S面(STSM S-Plane)的路径跟踪控制器,同时采用内外双环控制模式。外环即速度环采用Super-Twisting滑模控制,内环即姿态环采用S面控... 详细信息

针对小型固定翼无人机在执行任务时跟踪精度低以及容易受外界风影响的问题,设计基于Super-Twisting滑模S面(STSM S-Plane)的路径跟踪控制器,同时采用内外双环控制模式。外环即速度环采用Super-Twisting滑模控制,内环即姿态环采用S面控制。考虑到S面控制求导易导致积分爆炸的问题引入了二阶微分器,并对外界风组成进行建模研究。最后通过空间特殊曲线来验证所设计算法的控制性能。仿真结果表明,所设计的算法可以实现固定翼无人机对期望路径的精确跟踪,并具有良好的鲁棒性和抗干扰性能。

关键词：固定翼无人机 Super-Twisting滑模 S面控制风干扰

Anisotropic power spectrum and the observed low-l power in PLANCK CMB data

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Research in Astronomy and Astrophysics 2018年第3期18卷 47-56页

作者： zhe chang Pranati K.Rath Yu Sang Dong Zhao Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China Theoretical Physics Center for Science Facilities Chinese Academy of Sciences Beijing 100049 China

In this work,we study a direction dependent power spectrum in anisotropic Finsler spacetime. We use this direction dependent power spectrum to address the low-l power observed in WMAP and PLANCK data. The angular power spectrum of the temperature fluctuations has a lower amplitude in comparison to the ΛCDM model in the multipole range l = 2-40. Our theoretical model gives a correction to the isotropic angular power spectrum Cl^TT ldue to the breaking of rotational invariance of the primordial power spectrum. We estimate best-fit model parameters along with the six ΛCDM cosmological parameters using the PLANCK likelihood code in Cosmo MC software. We find that this modified angular power spectrum fits the CMB temperature data in the multipole range l = 2-10 to a good extent but fails for the whole multipole range l = 2-40.

关键词： cosmic background radiation - large-scale structure of universe

经脐单孔3D腔镜下肝总管-空肠改良Warren吻合术治疗儿童胆总管囊肿的效果观察

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罕少疾病杂志 2024年第8期31卷 78-79,85页

作者：常栋喆周良徐科耿宪杰郑州大学附属儿童医院、河南省儿童医院、郑州儿童医院普通外科河南郑州450000

目的探究经脐单孔3D腔镜下肝总管-空肠改良Warren吻合术治疗儿童胆总管囊肿的疗效。方法选取河南省儿童医院2012年8月至2022年8月收治的90例儿童胆总管囊肿患儿,使用随机数字法分为观察组(n=45)和对照组(n=45),观察组实施经脐单孔3D腔... 详细信息

目的探究经脐单孔3D腔镜下肝总管-空肠改良Warren吻合术治疗儿童胆总管囊肿的疗效。方法选取河南省儿童医院2012年8月至2022年8月收治的90例儿童胆总管囊肿患儿,使用随机数字法分为观察组(n=45)和对照组(n=45),观察组实施经脐单孔3D腔镜下肝总管-空肠改良Warren吻合术治疗,对照组行Roux-en-Y胆肠吻合术治疗,对比两组治疗有效率、手术相关指标、肝功能及术后并发症。结果观察组治疗有效率95.56%高于对照组82.22%(P<0.05);观察组手术时间、术中出血量、术后摄食时间及住院时间均低于对照组(P<0.05);观察组肝功能指标和术后并发症发生率均低于对照组(P<0.05)。结论针对儿童胆总管囊肿患儿,采用经脐单孔3D腔镜下肝总管-空肠改良Warren吻合术治疗具有良好的效果,在提升临床疗效,改善相关手术指标和肝功能指标,减少并发症等方面具有积极意义。

关键词：经脐单孔3D腔镜肝总管-空肠吻合改良Warren吻合术胆总管囊肿

Gravitational Collapse of a Spherical Star with Heat Flow as a Possible Energy Mechanism of Gamma-Ray Bursts

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Communications in Theoretical Physics 2008年第7期50卷 271-274页

作者： chang zhe GUAN Cheng-Bo HUANG Chao-Guang LI Xin Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China Department of Physics Weihai Branch of Shandong University Weihai 264209 China

We investigate the gravitational collapse of a spherically symmetric, inhomogeneous star, which is described by a perfect fluid with heat flow and satisfies the equation of state p = p/3 at its center. In the process of the gravitational collapse, the energy of the whole star is emitted into space. And the remaining spacetime is a Minkowski one without a remnant at the end of the process. For a star with a solar mass and solar radius, the total energy emitted is at the order of 10^54 erg, and the time-scale of the process is about 8 s. These are in the typical values for a gamma-ray burst. Thus, we suggest the gravitational collapse of a spherical star with heat flow as a possible energy mechanism of gamma-ray bursts.

关键词： gravitational collapse gamma-ray burst

The prospects of using gravitational waves for constraining the anisotropy of the Universe

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Chinese Physics C 2019年第7期43卷 112-117页

作者： Zhi-Chao Zhao Hai-Nan Lin zhe chang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Physics Chongqing UniversityChongqing 401331China

The observation of GW150914 gave a new independent measurement of the luminosity distance of a gravitational wave event. In this paper, we constrain the anisotropy of the Universe by using gravitational wave *** simulate hundreds of events of binary neutron star merger that may be observed by the Einstein Telescope. Full simulation of the production process of gravitational wave data is employed. We find that 200 binary neutron star merging events with the redshift in (0,1) observed by the Einstein Telescope may constrain the anisotropy with an accuracy comparable to that from the Union2.1 supernovae. This result shows that gravitational waves can be a powerful tool for investigating cosmological anisotropy.

关键词： gravitational wave anisotropic space-time gravitational wave detector