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“Conserved charges” of the Bondi-Metzner-Sachs algebra in the Brans-Dicke theory

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Chinese Physics C 2021年第2期45卷 377-393页

作者： Shaoqi Hou Zong-hong Zhu School of Physics and Technology Wuhan UniversityWuhan 430072China department of Astronomy Beijing Normal UniversityBeijing 100875China

The asymptotic symmetries in the Brans-Dicke theory are analyzed using Penrose's conformal completion method,which is independent of the coordinate system *** symmetries,indeed,include supertranslations and Lorentz transformations for an asymptotically flat *** the Wald-Zoupas formalism,“conserved charges”and fluxes of the Bondi-Metzner-Sachs algebra are *** scalar degree of freedom contributes only to the Lorentz boost charge,even though it plays a role in various *** flux-balance laws are further applied to constrain the displacement memory,spin memory,and center-of-mass memory effects.

关键词： Bondi-Metzner-Sachs symmetry conserved charges Brans-Dicke theory gravitational waves memory effects

Variational inequalities for the commutators of rough operators with BMO functions

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Science china mathematics 2021年第11期64卷 2437-2460页

作者： Yanping Chen Yong Ding Guixiang hong honghai Liu department of Applied mathematics School of Mathematics and PhysicsUniversity of Science and Technology BeijingBeijing 100083China School of Mathematical Sciences Beijing Normal UniversityLaboratory of Mathematics and Complex Systems(BNU)Ministry of EducationBeijing 100875China School of mathematics.and Statistics Wuhan UniversityWuhan 430072China School of mathematics.and Information Science Henan Polytechnic UniversityJiaozuo 454003China

Starting with the relatively simple observation that the variational estimates of the commutators of the standard Calderón-Zygmund operators with the bounded mean oscillation(BMO)functions can be obtained from their weighted variational estimates,we establish the similar variational estimates for the commutators of the BMO functions with rough singular integrals,which do not admit any weighted variational *** proof involves several Littlewood-Paley-type inequalities with the commutators as well as Bony decomposition and related para-product estimates.

关键词： commutator variational inequality singular integral averaging operator rough kernel

Strongly Lensed Transient Sources:A Review

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Chinese Physics Letters 2022年第11期39卷 72-91页

作者： Kai Liao Marek Biesiada Zong-hong Zhu School of Physics and Technology Wuhan UniversityWuhan 430072China National Centre for Nuclear Research Pasteura 702-093 WarsawPoland department of Astronomy Beijing Normal UniversityBeijing 100875China

The past decades have witnessed a lot of progress in gravitational lensing with two main targets:stars and galaxies(with active galactic nuclei).The success is partially attributed to the continuous luminescence of these sources making the detection and monitoring relatively *** the running of ongoing and upcoming large facilities/surveys in various electromagnetic and gravitational-wave bands,the era of time-domain surveys would guarantee constant detection of strongly lensed explosive transient events,for example,supernovae in all types,gamma ray bursts with afterglows in all bands,fast radio bursts,and even gravitational *** transients have many advantages over the traditional targets in studying the Universe,and magnification effect helps to understand the transients themselves at high *** this review article,on base of the recent achievements in literature,we summarize the methods of searching for different kinds of lensed transient signals,the latest results on detection and their applications in fundamental physics,astrophysics,and *** the same time,we give supplementary comments as well as prospects of this emerging research direction that may help readers who are interested in entering this field.

关键词： gravitational galaxies stars

Asymmetry in Negative Refraction of Nonlinear Waves

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Communications in Theoretical Physics 2009年第7期52卷 128-132页

作者： HUANG Xiao-Qing CUI Xiao-Hua CAO Zhou-Jian LIAO Xu-hong ZHANG hong HU Gang department of Physics Beijing Normal University Beijing 100875 China Institute of Applied mathematics Academy of Mathematics and System Science Chinese Academy of Sciences Beijing 100080 China Zhejiang Institute of Modern Physics and department of Physics Zhejiang University Hangzhou 310027 China

Recently, inwardly propagating waves （called antiwaves, AWs） in nonlinear oscillatory systems have attracted much attention. An interesting negative refraction phenomenon has been observed in a bidomain system where one medium supports forwardly propagating waves （normal waves, NWs） and the other AWs. In this paper we find that negative refraction （NR） in nonlinear media has an asymmetric property, i.e., NR can be observed only by applying wave source with proper frequency to one medium, but not the other. Moreover, NR appears always when the incident waves are dense and the refractional waves are sparse. This asymmetry is a particular feature for nonlinear NR, which can neither be observed in linear refraction processes （both positive and negative refractions） nor in nonlinear positive refraction. The mechanism underlying the asymmetry of nonlinear NR are fully understood based on the competition of nonlinear waves.

关键词： nonlinear waves negative refraction asymmetry

Do anogenital gland secretionsof giant panda code for their sexual ability?

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Chinese Science Bulletin 2006年第16期51卷 1986-1995页

作者： LIU Dingzhen YUAN hong TIAN hong WEI Rongping ZHANG Guiquan SUN Lixing WANG Liwen SUN Ruyong Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineer Institute of Ecology Beijing Normal University Beijing 100875 China china Research and Conservation Center for the Giant Panda Wolong Nature Reserve Wolong 623006 China department of Biological Sciences Central Washington University EUensburg Washington WA 98926-7537 USA department of Chemistry Beijing Normal University Beijing 100875 China

To test the hypothesis of whether ano- genital gland secretions (AGS) of giant panda code for their sexual ability, we collected AGS samples of 11 male (5 adult and 6 subadult) and 14 female (7 adult and 7 subadult) captive giant pandas (Ailuro- poda melanoleuca) from china Research and Con- servation Center for the Giant Panda at Wolong, Si- chuan, china from 1994 to 2002. The samples were analyzed by GC and GC-MS. The GC results showed that male and female pandas shared 20 constituents with equal capacity factors in the AGS. Further GC-MS analyses showed that there were a total of 95 compounds in the AGS. Nine constituents for the males and three for the females differed significantly in relative abundances between sexually active and inactive individuals, but no clear division between sexually active and inactive pandas by hierarchical cluster analyses on the relative abundances of a subset of 56 compounds. However, we were able to separate different age groups of male pandas by the constituents of AGS. 14 compounds were found sig- nificantly and negatively, and 8 compounds positively, correlated with pandas’ age by year. Our results suggest that the information contained in the AGS of panda might not code for pandas’ sexual ability but might for their age. These results will be valuable for captive breeding and conservation in the wild.

关键词： AGS GC-MS 光谱分析大熊猫性能力

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西北高等教育全面振兴的“特区模式”研究

高等理科教育 2024年第1期 57-64页

作者：买雪燕洪成文王钰金青海师范大学教育学院青海西宁810016 北京师范大学教育学部北京100875

振兴西北高等教育是贯彻落实党的二十大报告关于教育、科技、人才三位一体建设的重要内容。文章以“粤港澳大湾区”高等教育集群式发展为借鉴,提出建立西北高等教育“特区模式”的必要性和可行性,对其面临的区域性国家政策支持和地方政... 详细信息

振兴西北高等教育是贯彻落实党的二十大报告关于教育、科技、人才三位一体建设的重要内容。文章以“粤港澳大湾区”高等教育集群式发展为借鉴,提出建立西北高等教育“特区模式”的必要性和可行性,对其面临的区域性国家政策支持和地方政府投入有限、区域内学科建设与产业发展耦合度不高、外部环境对西部高校人才建设的冲击等不利因素进行了回应与分析,提出优化顶层政策设计和加大高等教育投入,增强产业升级贡献度和构建人才共享机制等对策,以期为振兴西北高等教育,促进区域经济社会高质量发展,推动西北地区共同富裕提供“靶向治疗”的重要依据。

关键词：西北高等教育 “特区模式” 学科建设

Wave Instability and Spatiotemporal Chaos in Reaction-Diffusion System with Oscillatory Dynamics

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Communications in Theoretical Physics 2006年第1期45卷 180-188页

作者： XIE Fa-Gen YANG Jun-Zhong LI hong-Gang Research department Kaiser Permanente 100 S. Los Robles Ave Pasadena CA 91101 USA School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China department of Systems Science Beijing Normal University Beijing 100875 China

We investigate the Turing-like wave instability of the uniform oscillator in oscillatory mediums using theoretical and flumerical methods. A propagating wave pattern originated at the corner of the system emerges when the uniform oscillator becomes unstable via Thring-like wave instability. Bifurcations from periodically propagated wave patterns to quasi-periodically propagated wave patterns, then to spatiotemporal chaos occur, as the system size increases from the instability threshold of the uniform oscillator.

关键词： wave instability oscillator reaction-diffusion chaos

Double-temperature ratchet model and current reversal of coupled Brownian motors

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Frontiers of physics 2017年第6期12卷 43-52页

作者： Chen-Pu Li hong-Bin Chen Zhi-Gang Zheng department of Physics Beijing Normal University Beijing 100875 China College of Science Hebei University of ArchitectureZhangjiakou 075000 China Institute of Systems Science (ISS) Huaqiao University Xiamen 361021 China College of Information Science and Engineering Huaqiao University Xiamen 361021 China

On the basis of the transport features and experimental phenomena observed in studies of molecular motors, we propose a double-temperature ratchet model of coupled motors to reveal tile dynamical mechanism of cooperative transport of motors with two heads, where the interactions and asynchrony between two motor heads are taken into account. We investigate the collective unidirectional trans- port of coupled system and find that the direction of motion can be reversed under certain conditions. Reverse motion can be achieved by modulating the coupling strength, coupling free length, and asym- metric coefficient of the periodic potential, which is understood in terms of the effective potential theory. The dependence of the directed current on various parameters is studied systematically. Di- rected transport of coupled Brownian motors can be manipulated and optimized by adjusting the pulsation period or the phase shift of the pulsation temperature.

关键词： coupled Brownian motors ratchet model effective potential noise

Determining H0 using a model-independent method

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Frontiers of physics 2017年第1期12卷 133-140页

作者： Pu-Xun Wu Zheng-Xiang Li hong-Wei Yu Center for Nonlinear Science and department of Physics Ningbo University Ningbo 315211 China Center for High Energy Physics Peking University Beijing 100080 China department of Astronomy Beijing Normal University Beijing 100875 China

By using type Ia supernovae （SNIa） to provide the luminosity distance （LD） directly, which depends on the value of the Hubble constant H0 = 100h km·s^-1· Mpc^-1, and the angular diameter distance from galaxy clusters or baryon acoustic oscillations （BAOs） to give the derived LD according to the distance duality relation, we propose a model-independent method to determine h from the fact that different observations should give the same LD at a given redshift. Combining the Sloan Digital Sky Survey II （SDSS-II） SNIa from the MLCS2k2 light curve fit and galaxy cluster data, we find that at the 1σ confidence level （CL）, h = 0.5867±0.0303 for the sample of the elliptical β model for galaxy clusters, and h = 0.6199± 0.0293 for that of the spherical β model. The former is smaller than the values from other observations, whereas the latter is consistent with the Planck result at the 2σ CL and agrees very well with the value reconstructed directly from the H（z） data. With the SDSS-II SNIa and BAO measurements, a tighter constraint, h = 0.6683 ± 0.0221, is obtained. For comparison, we also consider the Union 2.1 SNIa from the SALT2 light curve fitting. The results from the Union 2.1 SNIa are slightly larger than those from the SDSS-II SNIa, and the Union 2.1 SNIa ＋ BAOs give the tightest value. We find that the values from SNIa ＋ BAOs are quite consistent with those from the Planck and the BAOs, as well as the local measurement from Cepheids and very-low-redshift SNIa.

关键词： Hubble constant luminosity distance angular diameter distance