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A Model of Modified Newtonian Gravity Alternative to MOND, Consistent with the Properties of Spiral Galaxies and Compatible with Extragalactic Dark Matter
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作者 Maciej Rybicki 《Journal of Modern Physics》 CAS 2023年第1期72-87,共16页
A new model of the modified Newtonian gravity called Compacted & Collapsing Gravity (CCG) is proposed. Similar to the Milgrom’s MOND, it allows explaining the flattening of rotation curve in spiral galaxies, thus... A new model of the modified Newtonian gravity called Compacted & Collapsing Gravity (CCG) is proposed. Similar to the Milgrom’s MOND, it allows explaining the flattening of rotation curve in spiral galaxies, thus eliminates the need for dark matter at this level. However, in contrast to MOND, it puts a distinct limit on effective gravity;thereby constraints the sizes of single galaxies in connection to their masses, which complies with observations. In the bigger than single galaxies structures such as galaxy clusters, CCG rather complements than replaces interpretations of the observational data based on dark matter. Besides, the new model provides a plausible explanation to the hierarchical structure of the universe. 展开更多
关键词 Spiral Galaxies Flattening of Rotation Curve Gravitational Lensing Dark Matter (DM) Modified Newtonian Dynamics (MOND)
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Shift-share Analysis on International Tourism Competitiveness——A Case of Jiangsu Province 被引量:9
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作者 SHI Chunyun ZHANG Jie +1 位作者 YANG Yang ZHOU Zhang 《Chinese Geographical Science》 SCIE CSCD 2007年第2期173-178,共6页
Shift-share analysis has been confirmed a useful approach in the study of regional economics and many kinds of extended shift-share models have been advanced and put into practice in economic studies, but few have hit... Shift-share analysis has been confirmed a useful approach in the study of regional economics and many kinds of extended shift-share models have been advanced and put into practice in economic studies, but few have hitherto been introduced and applied to the tourism research in China. Moreover understanding the spatially competitive relationship is of paramount importance for marketers, developers, and planners involved in tourism strategy development. Based on international tourism receipts from 1995 to 2004, this study aims at probing into the spatial competitiveness of interna- tional tourism in Jiangsu Province in comparison with its neighbors by applying a spatially extended shift-share model and a modified dynamic shift-share model. The empirical results illustrate that exceptional years may exist in the ap- plication of dynamic shift-share models. To solve this issue, modifications to dynamic shift-share model are put forward. The analytical results are not only presented but also explained by the comparison of background conditions of tourism development between Jiangsu and its key competitors. The conclusions can be drawn that the growth of international tourism receipts in Jiangsu mainly attributes to the national component and the competitive component and Zhejiang is the most important rival to Jiangsu during the period of 1995-2004. In order to upgrade the tourism competitiveness, it is indispensable for Jiangsu to take proper positioning, promoting and marketing strategies and to cooperate and integrate with its main rivals. 展开更多
关键词 international tourism competitiveness spatially extended shift-share analysis model comparative static shift-share analysis modified dynamic shift-share analysis Jiangsu Province
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Debye Entropic Force and Modified Newtonian Dynamics 被引量:1
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作者 李昕 常哲 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第4期733-736,共4页
Verlinde has suggested that the gravity has an entropic origin, and a gravitational system could be regarded as a thermodynarnical system. It is well-known that the equipartition law of energy is invalid at very low t... Verlinde has suggested that the gravity has an entropic origin, and a gravitational system could be regarded as a thermodynarnical system. It is well-known that the equipartition law of energy is invalid at very low temperature. Therefore, entropic force should be modified while the temperature of the holographic screen is very low. It is shown that the modified entropic force is proportional to the square of the acceleration, while the temperature of the holographic screen is much lower than the Debye temperature TD. The modified entropic force returns to the Newton's law of gravitation while the temperature of the holographic screen is much higher than the Debye temperature. The modified entropic force is connected with modified Newtonian dynamics (MOND). The constant ao involved in MOND is linear in the Debye frequency WD, which can be regarded as the largest frequency of the bits in screen. We find that there do have a strong connection between MOND and cosmology in the framework of Verlinde's entropic force, if the holographic screen is taken to be bound of the Universe. The Debye frequency is linear in the Hubble constant Ho. 展开更多
关键词 entropic force modified Newtonian dynamics
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Triethylamine or diethylenetriamine as dynamic modifier for suppressing basic protein adsorption in capillary electrophoresis
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作者 Ying Hua QIU Al Jin HUANG Yi Liang SUN(Department of Chemistry. Peking University. Beijing 100871) 《Chinese Chemical Letters》 SCIE CAS CSCD 1999年第3期227-230,共4页
Either triethylamine or diethylenetriamine can be conveniently used as a dynamic modifier to suppress the adsorption of basic proteins in capillary zone electrophoresis. Sufficiently high column efficiencies (> 2x1... Either triethylamine or diethylenetriamine can be conveniently used as a dynamic modifier to suppress the adsorption of basic proteins in capillary zone electrophoresis. Sufficiently high column efficiencies (> 2x10(5) plates/m for cytochrome C) were obtained with either of them along with the improvement of the peak shapes and repeatability of migration time. The relationship between the adsorption suppression effect of the modifier and its structure was discussed. 展开更多
关键词 capillary zone electrophoresis basic proteins dynamic modifier triethylamne DIETHYLENETRIAMINE
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Modal interactions in primary and subharmonic resonant dynamics of imperfect microplates with geometric nonlinearities
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作者 Hamed Farokhi Mergen H.Ghayesh 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第3期469-480,共12页
This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-... This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff's hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are analysed.Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms. 展开更多
关键词 Modal interactions Microplate Sizedependent dynamics Modified couple stress theory Stability
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MOUND: An Alternative to Milgrom’s MOND
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作者 Patrick G. Tonin 《International Journal of Astronomy and Astrophysics》 2021年第1期87-94,共8页
We test and explore a Modified Universe Dynamics (MOUND) formula recently proposed by the author. We show that, similarly to Milgrom’s Modified Newtonian Dynamics (MOND), it is successful in accounting for the mass d... We test and explore a Modified Universe Dynamics (MOUND) formula recently proposed by the author. We show that, similarly to Milgrom’s Modified Newtonian Dynamics (MOND), it is successful in accounting for the mass discrepancy in spiral galaxies, and it predicts the Baryonic Tully-Fisher Relation (BTFR) and the Radial Acceleration Relation (RAR). Contrary to Milgrom’s MOND, MOUND also explains the dynamics of galaxy clusters and does not rely on an empirical interpolating function or an ad hoc acceleration parameter. 展开更多
关键词 Cosmological Models Dark Matter Modified Newtonian Dynamics
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Variable Speed of Light with Time and General Relativity
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作者 Giuseppe Pipino 《Journal of High Energy Physics, Gravitation and Cosmology》 2021年第2期742-760,共19页
In a previous article entitled: “Evidences for varying speed of light with time” [1], a series of observational evidence was presented in favor of the hypothesis that the speed of light varies with time according to... In a previous article entitled: “Evidences for varying speed of light with time” [1], a series of observational evidence was presented in favor of the hypothesis that the speed of light varies with time according to the relationship d<i>c</i>/d<i>t</i> = -<i>Hc</i>, where <i>H</i> is the Hubble constant which is considered a universal constant. In this paper we propose to elaborate on the observational evidence supporting the hypothesis, and to probe the consequences of this relationship on General Relativity. Also we will provide a theoretical justification of the previous relationship and we will show how from it we can deduce galactic velocity curves. We can deduce the important empirical Tully-Fisher relation linking these curves to the baryonic mass of the galaxy and we can justify the apparent accelerated expansion of the universe without intervening elusive entities such as dark matter and dark energy. 展开更多
关键词 Abnormal Acceleration Modified Newtonian Dynamic Tully-Fisher Relation REDSHIFT Hubble’s Law Dark Matter Dilation of Light Curves of Supernovae Ia Acceleration of Expansion of Universe General Relativity
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Modified multi-scale symbolic dynamic entropy and fuzzy broad learning-based fast fault diagnosis of railway point machines
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作者 Junqi Liu Tao Wen +1 位作者 Guo Xie Yuan Cao 《Transportation Safety and Environment》 EI 2023年第4期1-7,共7页
Railway point machine(RPM)condition monitoring has attracted engineers’attention for safe train operation and accident prevention.To realize the fast and accurate fault diagnosis of RPMs,this paper proposes a method ... Railway point machine(RPM)condition monitoring has attracted engineers’attention for safe train operation and accident prevention.To realize the fast and accurate fault diagnosis of RPMs,this paper proposes a method based on entropy measurement and broad learning system(BLS).Firstly,the modified multi-scale symbolic dynamic entropy(MMSDE)module extracts dynamic characteristics from the collected acoustic signals as entropy features.Then,the fuzzy BLS takes the above entropy features as input to complete model training.Fuzzy BLS introduces the Takagi-Sug eno fuzzy system into BLS,which improves the model’s classification performance while considering computational speed.Experimental results indicate that the proposed method significantly reduces the running time while maintaining high accuracy. 展开更多
关键词 railway point machine(RPM) fault diagnosis modified multi-scale symbolic dynamic entropy(MMSDE) fuzzy board learning system(BLS)
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Gravitational Field as a Pressure Force from Logarithmic Lagrangians and Non-Standard Hamiltonians:The Case of Stellar Halo of Milky Way 被引量:3
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作者 Rami Ahmad El-Nabulsi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第3期233-240,共8页
Recently,the notion of non-standard Lagrangians was discussed widely in literature in an attempt to explore the inverse variational problem of nonlinear differential equations.Different forms of non-standard Lagrangia... Recently,the notion of non-standard Lagrangians was discussed widely in literature in an attempt to explore the inverse variational problem of nonlinear differential equations.Different forms of non-standard Lagrangians were introduced in literature and have revealed nice mathematical and physical properties.One interesting form related to the inverse variational problem is the logarithmic Lagrangian,which has a number of motivating features related to the Li′enard-type and Emden nonlinear differential equations.Such types of Lagrangians lead to nonlinear dynamics based on non-standard Hamiltonians.In this communication,we show that some new dynamical properties are obtained in stellar dynamics if standard Lagrangians are replaced by Logarithmic Lagrangians and their corresponding non-standard Hamiltonians.One interesting consequence concerns the emergence of an extra pressure term,which is related to the gravitational field suggesting that gravitation may act as a pressure in a strong gravitational field.The case of the stellar halo of the Milky Way is considered. 展开更多
关键词 logarithmic Lagrangian non-standard Hamiltonians modified Boltzmann equation stellar dynamics Milky way
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Constitutive analysis and optimization on hot working parameters of as-cast high Cr ultra-super-critical rotor steel with columnar grains 被引量:1
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作者 Zong-ye Ding Di Zhang +2 位作者 Qiao-dan Hu Long Zeng Jian-guo Li 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第9期916-924,共9页
Isothermal hot compression tests on the as-cast high-Cr ultra-super-critical rotor steel with columnar grains were carried out in the temperature range from 1223 to 1523Kand at strain rates from 0.001 to 1s^(-1).The... Isothermal hot compression tests on the as-cast high-Cr ultra-super-critical rotor steel with columnar grains were carried out in the temperature range from 1223 to 1523Kand at strain rates from 0.001 to 1s^(-1).The compression direction was parallel to the longitudinal direction of columnar grains.The constitutive equation based on Arrhenius model was presented,and the processing maps based on the dynamic material model were developed,correlating with microstructure observation.The main softening mechanism was dynamic recovery at 1223 Kunder strain rates from 0.1to 1s^(-1),whereas it was dynamic recrystallization under other deformation conditions.The constitutive equation modified by strain compensation reasonably predicted the flow stresses.The processing maps and microstructure evolution mechanism schematic indicated that the optimum hot working parameters lay in the zone defined by the temperature range from 1423 to 1473Kand the strain rate range from 0.001 to 1s^(-1). 展开更多
关键词 As-cast ultra-super-critical rotor steel Columnar grain Dynamic recrystallization Modified constitutive equation Processing map
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Numerical analysis of residence time distribution of solids in a bubbling fluidized bed based on the modified structure-based drag model 被引量:4
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作者 Zheng Zou Yunlong Zhao +4 位作者 Hu Zhao Hongzhong Li Qingshan Zhu Zhaohui Xie Yingbo Li 《Particuology》 SCIE EI CAS CSCD 2017年第3期30-38,共9页
The residence time distribution (RTD) of solids and the fluidized structure of a bubbling fluidized bed were investigated numerically using computational fluid dynamics simulations coupled with the modified structur... The residence time distribution (RTD) of solids and the fluidized structure of a bubbling fluidized bed were investigated numerically using computational fluid dynamics simulations coupled with the modified structure-based drag model. A general comparison of the simulated results with theoretical values shows reasonable agreement. As the mean residence time is increased, the RTD initial peak intensity decreases and the RTD curve tail extends farther. Numerous small peaks on the RTD curve are induced by the back- mixing and aggregation of particles, which attests to the non-uniform flow structure of the bubbling fluidized bed. The low value of t50 results in poor contact between phases, and the complete exit age of the overflow particles is much longer for back-mixed solids and those caught in dead regions. The formation of a gulf-stream flow and back-mixing for solids induces an even wider spread of RTD. 展开更多
关键词 FluidizationResidence time distribution Bubbling fiuidized bed Modified structure-based drag mode Computational fluid dynamics CFD
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Probing the universality of acceleration scale in modified Newtonian dynamics with SPARC galaxies
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作者 Xin Li Su-Ping Zhao +1 位作者 Hai-Nan Lin Yong Zhou 《Chinese Physics C》 SCIE CAS CSCD 2021年第2期598-605,共8页
We probe the universality of acceleration scale a_(0) in Milgrom's modified Newtonian dynamics(MOND)using the recently released rotation curve data from SPARC galaxies.We divide the SPARC data into different subsa... We probe the universality of acceleration scale a_(0) in Milgrom's modified Newtonian dynamics(MOND)using the recently released rotation curve data from SPARC galaxies.We divide the SPARC data into different subsamples according to the morphological types of galaxies,and fit the rotation curve data of each subsample with the theoretical prediction of MOND.MOND involves an arbitrary interpolation function which connects the Newtonian region and the MOND region.Here we consider five different interpolation functions that are widely discussed in the literature.It is shown that the best-fitting a_(0) significantly depends on the interpolation functions.For a specific interpolation function, a_(0) also depends on the morphological types of galaxies,implying that a_(0) may be not a universal constant.Introducing a dipole correction to a_(0) can significantly improve the fits.The dipole directions for four of the five interpolation functions point towards an approximately consistent direction,but a_(0) still varies for different interpolation functions. 展开更多
关键词 kinematics and dynamics dark matter modified Newtonian dynamics
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