Physics & Astronomy International Journal最新文献_第4页

On levy-walk model for correlations in spatial galaxy distribution 空间星系分布相关性的levy-walk模型

Physics & Astronomy International Journal Pub Date : 2019-03-29 DOI: 10.15406/paij.2019.03.00162

V. Uchaikin

{"title":"On levy-walk model for correlations in spatial galaxy distribution","authors":"V. Uchaikin","doi":"10.15406/paij.2019.03.00162","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00162","url":null,"abstract":"One of important problems complicating the extraction of information from cosmological surveys, is necessity to supplement observational data subtracted of foreground or for some (i.e. technical) reasons removed from the survey. This particularly affects the extraction of information from the largest observable scales. Maximum-likelihood estimators are not quite applicable for reconstructing the full-sky because of non-Caussian character of observed matter distribution. To solve this problem, many authors modify implementations of such estimators which are robust to the leakage of contaminants from within masked regions. The trouble arises from the need to satisfy the cosmological principle of an arbitrary choice of the reference frame and long-distant correlations in spatial galaxy distribution observed. We are going to discuss here one а such approach and to show some results of its application. The discussion about homogeneity (or inhomogeneity) of the large-scale visible matter distribution in the Universe is attracting the attention of both the astronomers and theoreticians of cosmology.1–4 In recent years the more complete and deeper galaxy surveys become available,5,6 however, this does not eliminate the question about fractality of the large-scale structure. The fractal concept, introduced by Mandelbrot,7 applied to the galaxy distribution means the presence of the overdence regions and voids extending to all scales, at least to those could be reached by now. Mathematically, it formulates as","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114968861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Possible model of forming relativistic jets and disks in astrophysical objects 在天体物理物体中形成相对论性喷流和盘的可能模型

Physics & Astronomy International Journal Pub Date : 2019-03-29 DOI: 10.15406/paij.2019.03.00163

G. Kichigin

{"title":"Possible model of forming relativistic jets and disks in astrophysical objects","authors":"G. Kichigin","doi":"10.15406/paij.2019.03.00163","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00163","url":null,"abstract":"Recently, astrophysicists have paid a special attention to such observational events in space as supernova, gamma-ray bursts (GRB), bursters, processes in active galactic nuclei (AGNs), quasars, etc. They are considered to emerge due to catastrophic processes in space, as a result of which a compact region forms, wherefrom a powerful electro-magnetic radiation emits, and fluxes of various energetic particles eject. We assume that the latter are cosmic rays (CRs). In this paper, I focus on the quasi-spherical region produced at the catastrophe site. This region is a source of relativistic and ultrarelativistic particles. This region existence time is determined by the processes occurring inside that may be either short-, or long-term. For example, to elucidate the formation of pulsing GRB,1 the popular fireball model Piran2 is used. This model presupposes that there forms a compact ball (with the initial size of about 100 km) expanding at a relativistic velocity and comprising the quanta locked in it and electron-positron pairs. At an instant, quanta dramatically leave the ball thus forming a short gamma burst. Further, charged relativistic particles eject. They are accelerated in shocks (inner and outer) produced as a result of the ball shell “bloating” in a plasma medium at a near-light velocity, and of fast motion of substance in the ball.","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114974626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessing site response through ambient noise measurements in a seismic prone area 通过测量地震易发地区的环境噪音来评估现场的反应

Physics & Astronomy International Journal Pub Date : 2019-03-19 DOI: 10.15406/paij.2019.03.00161

R. Biswas, S. Baruah

{"title":"Assessing site response through ambient noise measurements in a seismic prone area","authors":"R. Biswas, S. Baruah","doi":"10.15406/paij.2019.03.00161","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00161","url":null,"abstract":"Northeast Region (NER) of India, bounded by latitude (28-30 0N) and Longitude (89-98 0E), is seismically one of the most active zones in the world where sixteen large (M>7.0) and two great earthquakes of June 12, 1897(M 8.5)1 and August 15, 1950 (M=8.7)2 occurred during the last hundred years. These two great earthquakes have caused extensive destruction killing a total of 3,042 lives and a total loss of $ 30 million.3 Consequently, the NER, India lays in the seismic zone V of India.4 The zone V is the maximum rating zone of India. Shillong Plateau is a part of the Indian Shield, which is separated out from the peninsular shield and moved to the east by about 300 Km along the Dauki Fault.5 The gigantic E-W trending Dauki Fault separates the plateau from the Himalaya to the North. The E-W segment of the river at the northern boundary of the Plateau is named Brahmaputra fault.6 The Shillong City, i.e., the study area is situated in Shillong Plateau. The complex geotectonic setup of Shillong City needs better understanding of site-amplification characteristics. The city in particular has not been covered by any proper estimation of fundamental frequency. It has been observed that the damage associated with the occurrence of earth tremors is not only due to magnitude of the earthquake of earth tremors and its epicentral distance, but also due to local site effects which are essentially frequency dependent caused by the topography and geology of the site.7","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126198900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Dark energy model and its development 暗能量模型及其发展

Physics & Astronomy International Journal Pub Date : 2019-03-14 DOI: 10.15406/PAIJ.2019.03.00160

B. Borah

{"title":"Dark energy model and its development","authors":"B. Borah","doi":"10.15406/PAIJ.2019.03.00160","DOIUrl":"https://doi.org/10.15406/PAIJ.2019.03.00160","url":null,"abstract":"particle physics and we cannot talk about a well-established theory of cosmology, in which one can measure the parameters with high precision. With all this, one can say that cosmology is living nowadays a golden epoch and the observational data, which become more and more precise, keeps cosmologists optimistic about establishing a true Standard Cosmological Theory in the near future. If we try to know the origin of the universe then the most accepted model in this direction is the Big Bang theory. The Big Bang theory is an effort to explain what happened at the very beginning of our universe. Discoveries in astronomy and physics have shown beyond a reasonable doubt that our universe did in fact have a beginning. Prior to that moment there was nothing; during and after that moment there was something: our universe. So simply we can say that the big bang theory is an effort to explain what happened during and after that moment. In the early 1990’s, one thing was fairly certain about the expansion of the Universe. It might have enough energy density to stop its expansion and collapse. It might have so little energy density that it would never stop expanding, but gravity was certain to slow down the expansion as time went on.","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131253277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Formation and characterization of non uniform reversible optical fiber gratings with single and double sided loading 单侧和双侧负载非均匀可逆光纤光栅的形成和特性

Physics & Astronomy International Journal Pub Date : 2019-03-14 DOI: 10.15406/paij.2019.03.00159

S. Ugale

{"title":"Formation and characterization of non uniform reversible optical fiber gratings with single and double sided loading","authors":"S. Ugale","doi":"10.15406/paij.2019.03.00159","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00159","url":null,"abstract":"Long period fiber grating (LPFG) can be realized with permanent modification of fiber such as UV induced refractive index changes and etching or temporary alternation of fiber propagation characteristics. LPFG by UV light exposure with amplitude phase mask are popular, but their spectra can hardly be tuned once they have been fabricated, which may limit applications of LPFG. The temporary or reversible grating can be implemented through the application of acoustic wave to the fiber1,2 or periodical loading onto the fiber.3 Reversible optical fiber gratings need neither a special fiber nor an expensive writing device for fabrication. These gratings also offer advantages of being simple, inexpensive, erasable, reconfigurable, and also give flexible control of transmission spectrum. Depending upon refractive index profile and grating period variation, gratings are of different types. The grating period can be uniform or graded, and either localized or distributed in structure. Uniform optical fiber grating yields highly undesirable side-lobes due to the sharp boundaries of the grating.4 A well-discussed method to reduce these side lobes is to apodize the grating coupling strength along the grating by gradually tapering the refractive index modulation amplitude to zero at both end of the grating. Periodic refractive index perturbations in an optical grating with single sided loading could be primarily stress induced, since the points of stress would be those where the plate presses the fiber against the grooved plate. While in an optical grating with double sided loading refractive index perturbation is due to the periodic microbend.","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122023997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Five snippets of signal analysis 五个片段的信号分析

Physics & Astronomy International Journal Pub Date : 2019-03-12 DOI: 10.15406/paij.2019.03.00158

G. Travaglini

{"title":"Five snippets of signal analysis","authors":"G. Travaglini","doi":"10.15406/paij.2019.03.00158","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00158","url":null,"abstract":"Signal Analysis currently features tests and procedures addressed at verifying certain hypotheses, such as linearity, stationarity, changes of regime, and the kind of information utilized in back/forecasting time series, possibly by calibration. In such context, methodological updates are required, especially when it comes to dealing with series characterized by high irregularities or when unobservable are involved as in the case of Kalman filtering.1,2 Many Regime-Switching techniques, for instance, are affected by strict requirements such as stationarity and single-point shift3,4 which require amelioration or updating. Similarly, time-varying parameters utilized for back/ forecasting purposes are better computed in a Bayesian context, in order to exploit prior pieces of evidence based on their known distribution. Finally, current stationarity tests5,6 in a nonlinear setting with dramatic changes in trend and subsample variances may require substantial corrections. Section 1 is devoted to defining random signals, whereas Section 2 tackles the issue of Regime-Switch testing. Section 3 produces a novel technique in the field of signal smoothing. The following two sections illustrate the steps for implementing Bayesian Monte Carlo simulation and calibration, whereas the final section is addressed at supplying corrected stationarity tests. Section 7 concludes.","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115152648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The lagrangian formalism for the derivation of Vlasov and Liouville equations on the (co)tangent bundles (co)切束上Vlasov方程和Liouville方程推导的拉格朗日形式

Physics & Astronomy International Journal Pub Date : 2019-03-11 DOI: 10.15406/paij.2019.03.00157

N. Fimin

引用次数: 0

Connections of energy, time, matter, space and charge in universe (v4) 宇宙中能量、时间、物质、空间和电荷的联系(v4)

Physics & Astronomy International Journal Pub Date : 2019-02-21 DOI: 10.15406/paij.2019.03.00156

A. Bolonkin

引用次数: 0

A simple theoretical analysis of quantum biomathematical model of DNA and heisenberg spin chain model 对DNA的量子生物数学模型和海森堡自旋链模型进行了简单的理论分析

Physics & Astronomy International Journal Pub Date : 2019-02-05 DOI: 10.15406/paij.2019.03.00155

S. Roy

{"title":"A simple theoretical analysis of quantum biomathematical model of DNA and heisenberg spin chain model","authors":"S. Roy","doi":"10.15406/paij.2019.03.00155","DOIUrl":"https://doi.org/10.15406/paij.2019.03.00155","url":null,"abstract":"It is now well known that DNA can be regarded as a physical elastic object in a viscous environment. Two strands of double helix are anti-parallel and two polynucleotide chains are coiled about the same axis such that B-DNA (Z-DNA) has right-handed (left-handed) helical sense. In earlier studies it has been shown that elongation verses force characteristics of a DNA molecule1 can be described2 by the worm-like-chain (WLC) which essentially depicts a chain by an elastic continuous curve at thermal equilibrium with a single elastic constant, the persistence length A characterizing the bending energy.3 It has been shown that the analytic solution of WLC can be achieved through the mapping to a quantum mechanical problem. In fact its partition function corresponds to Euclidean path integral for a quantum dumbbell when rotations and vibrations are ignored so that it represents a rigid rotator. The generalization of the WLC with twist rigidity was considered by Bouchiat et al.4 and it was shown that a DNA molecule at small super coiling can be described by a thin elastic rod involving the twist rigidity. It is called the rod –like –chain (RLC) model. The partition function can be mapped onto the path integral representation for a quantum charged particle in the field of a magnetic monopole with nonquantized charge.4 The theory is singular in the continuum limit and needs to be regularized at an intermediate length scale. It is found that the model is in good agreement with the experimental data at small super coiling region.","PeriodicalId":137635,"journal":{"name":"Physics & Astronomy International Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122418828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design optimization of non-zero dispersion shifted fiber for latency mitigation in optical fiber network 非零色散移位光纤的设计优化，以降低光纤网络中的延迟

Physics & Astronomy International Journal Pub Date : 2019-01-29 DOI: 10.15406/paij.2019.03.00153

Faramarz E. Seraji, S. Safari, Marzieh Sadat Kiaee

引用次数: 2