Radar observations of the Lyrid meteor shower at Budrio

Summary Radar meteor observations carried out at Budrio (Italy) during the Lyrid meteor shower period in 1983–1985 are analysed and discussed. Lyrid activity is obtained applying to the observations a range distribution method. The maximum of activity is found at solar longitude 31.3° (epoch 1950), the duration of the shower between quartermaximum points is about 2 days and the overall Lyrid activity approximately 6 days.

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Riassunto Si analizzano e si discutono i risultati delle osservazioni radar di meteore effettuate negli anni 1983–1985 a Budrio (Italia) nel periodo dello sciame delle Liridi. L'attività delle Liridi è ottenuta da un metodo che fa ricorso alla distribuzione delle distanze, dei radioechi. Il massimo dell'attività è identificato alla longitudine solare di 31.3° la durata dello sciame valutata tra punti ad un quarto del massimo è di circa 2 giorni, e l'attività complessiva delle Liridi risulta essere approssimativamente di 6 giorni.

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Резюме Изучаются радиолокационные наблюдения метеорного потока Лирид проведенные в Будрио (Италия) в 1983–1985 гг. Активнссть потока получена методом распределения дальностей радиоэхо. Максимум активности наблюдалось на долготе Солнца 31.3° (равноденствие 1950), длительность повышенной активности между пунктами с 1/4 максимальной численности получилась около 2 дней; Лириды можно выделуть из спорадического фона в течение приблизительно 6 дней.

     

Kavli Institute for Astronomy and Astrophysics at Peking University

The Kavli Institute for Astronomy and Astrophysics at Peking University （KIAA-PKU） was found in 2007. which was jointly supported by Peking University and Kavli Foundation （USA）. KIAA-PKU is dedicated to promoting basic research in China with the highest international standards,     

A new method of discovering new meteor showers from the IMO single-station video meteor database

It has been found that unknown meteor showers could be efficiently discovered from the single station video meteor database of the International Meteor Organization (IMO) by assuming the geocentric velocity and adjusting it within the dynamically permitted range. The mean geocentric velocities of new meteor showers can be obtained, as well as the coordinates of the radiants. The activity period and maximum time can also be obtained if there are sufficient shower meteors. All single station video meteor observations between February 13 and 17 (from 2000 to 2005) in IMO’s database are processed with this method. As a result, two new meteor showers, one near RA=245.10°, Dec=41.82° in Hercules and the other near RA=233.03°, Dec=17.04° in Serpenids, are discovered. Some dynamical characteristics of the new meteor showers are also determined. Considering the random nature on the selection of period in this work, it is expected that there are some more potential new meteor showers in IMO’s video database. Supported by the National Natural Science Foundation of China (Grant No. 10373004)     

邮票上的物理学史(63) --天体物理学:新的观测手段

天体物理学是天文学三大分支中最现代和最活跃的一个分支(另外两个分支是天体测量学和天体力学),也是物理学的一个重要分支,它研究的对象是自然界中尺度最大的客体天体和宇宙,而且它们是处在人类在地球上无法复现的极端物理条件(超高温、超高压、超高密度、超强磁场、超强辐射等)之下.     

On the 1986 Ursids meteor shower observed at Budrio

Summary Outburst in activity of the 1986 Ursids reported from visual observations was observed also by the Budrio meteor radar. The radar maximum consisting mainly of long-duration echoes preceded the visual one by about half an hour. The peak appeared on December 22, 20∶49 UT (solar longitude 270°.202). The mean photographic orbit of the Ursids shower was derived and compared with that of the parent comet Tuttle.     

邮票上的物理学史（64）--天体物理学:新的观测手段(续)

空间技术的发展,使得有可能建造空间观测站,到太空去观测,由此建立了空间天文学.它带来的好处是:①突破大气窗口限制,把观测波段从可见光和射电波扩展到电磁波全波段,包括红外、紫外、X射线和γ射线.我们还记得,天体物理学是伴随着光谱分析而建立起来的,依靠望远镜收集的一点星光,通过测量天体的亮度和分析天体的光谱,就建立了天体物理学,现在将观测扩展到全部电磁波段,得到的信息、发现的现象就更多了.②对地面能观测的波段,也减轻或消除了大气湍动的影响,提高了分辨本领.对光学望远镜成像主要有三个限制:衍射;大气宁静度;望远镜本身的缺陷.事实上,对一些大口径望远镜,大气湍动对成像的破坏作用远远超过了衍射限制.     

原子能院的核天体物理研究和串列升级工程进展(英文)

在北京串列实验室建立了次级束流实验装置 ,用于放射性核束物理和核天体物理研究 .先后开展了7Be(d ,n) 8B ,11C(d ,n) 12 N ,8Li(d ,p) 9Li和6 He(p ,n) 6 Li核天体物理重要反应的研究 .介绍了串列加速器升级工程的进展情况 .该工程在现有串列加速器的基础上 ,将建立 10 0MeV/ 2 0 0 μA的质子回旋加速器、在线同位素分离器和超导加速段 .在此装置上 ,将可以产生质量数最高为 12 0 ,强度最高为 10 9particles/s的放射性束流 . A secondary beam line (GIRAFFE) at the Beijing Tandem accelerator lab was constructed for yielding low energy secondary beams. The current progress on the study of nuclear astrophysics and nuclear structure is presented. Up to now, We have carried out measurement of~(7)Be(d, n)~( 8)B,~(11)C(d, n)~(12)N,~(8)Li(d, p)~(9)Li, and~(6)He(p, n)~(6)Li reactions. The proposed Beijing radioactive nuclear beam facility (BRIF ) and its current R&D progress are briefly introduced. This facility is based on...     

A new interpretation of the Ψ-resonances

Recent experimental discoveries favor speculations that there may be several new “flavors” of tricolored quarks. We interpret the Ψ(3095) and Ψ′(3684) resonances as bound states composed of the two new quark flavors of electric charge 2/3 required by the minimal vectorlike theory of the weak interactions. Implications for e⁺e^?-annihilation and neutrino production are discussed.     

Prospects for new physics observations in diffractive processes at the LHC and Tevatron

We study the double-diffractive production of various heavy systems (e.g. Higgs, dijet, and SUSY particles) at LHC and Tevatron collider energies. In each case we compute the probability that the rapidity gaps, which occur on either side of the produced system, survive the effects of soft rescattering and QCD bremsstrahlung effects. We calculate both the luminosity for different production mechanisms, and a wide variety of subprocess cross sections. The results allow numerical predictions to be readily made for the cross sections of all these processes at the LHC and the Tevatron collider. For example, we predict that the cross section for the exclusive double-diffractive production of a 120 GeV Higgs boson at the LHC is about 3 fb, and that the QCD background in the decay mode is about 4 times smaller than the Higgs signal if the experimental missing-mass resolution is 1 GeV. For completeness we also discuss production via or WW fusion. Received: 7 November 2001 / Revised version: 11 December 2001 / Published online: 25 January 2002     

一类生灭过程及其在核天体物理计算中的应用

研究一类生灭过程,利用矩阵分解技巧求出了生灭过程微分方程的解,并将之应用于核天体物理中太阳系慢中子俘获过程重元丰度计算问题研究,计算结果与天文观测值一致.     

兰州320kV高压平台低能核天体物理实验研究进展(英文)

在低温核天体物理环境下,如静态核稳定燃烧阶段的核反应都发生较低的能区,其伽莫夫窗口内的核反应截面非常小,这就需要加速器提供较强束流才能完成核反应截面的直接测量。最近在中国科学院近代物理的320 kV高压平台上建立了低能核天体物理实验室以及相应的研究平台。驱动该平台的是一个14.5 GHz的永磁铁型ECR离子源,它能够提供非常强的束流离子。对于质子和氦离子,离子源出口的最大流强可以达到100 eμA,在实验终端上可以获得大约30 eμA的流强。基于此强流加速器装置,我们建立了核天体物理实验测量装置,包括靶室以及带电粒子和伽玛射线探测器等设备。利用已知的核反应对探测器性能和实验方法进行了一系列测试。同时,展示了近年来取得的一些主要实验结果。最后,对该平台上开展工作的前景进行了展望,并指出基于该地面装置的低能核反应研究所积累的技术及经验对于我国锦屏深地核天体物理JUNA项目的重要意义。For the hydrostatic stable burning in stars, the Gamow window is well below the Coulomb barriers for the charged-particle-induced nuclear reaction involved. Such nuclear reaction occurs through the quantum-mechanics tunneling effect, and its cross section drops rapidly approaching the Gamow window. An accelerator which can provide intense beam current is thus required to directly measure the reactions at low energies. An experimental setup for low-energy nuclear astrophysics studies has been recently established at a 320 kV high-voltage platform of the Institute of Modern Physics (IMP), Lanzhou, China. The driver machine of this platform is a very strong ECR ion source employing all-permanent magnets, which can typically supply up to about 100 eμA proton, alpha and many other heavy ions, and ultimately about 30 eμA currents can be achieved at the experimental terminal. The experimental setup includes a target chamber, and the charged-particle and γ-ray HPGe detectors. This work describes the setup established, characteristics of detectors, methodologies, and test results of several reactions with known cross sections. Furthermore, some important results published are shown briefly. We believe that the experimental technologies developed and experiences accumulated at this above-ground platform will be extremely helpful for the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project in China.     

Application of the 5-Dimensional Projective Unified Field Theory to Cosmology and Astrophysics

Projective Unified Field Theory of the author leads to a cosmology without big bang. Since details have been published in a series of papers, the aim of this article is to inform about the theoretical and numerical results with respect to cosmology and astrophysics: age of the universe, Hubble factor, deceleration parameter, equation of motion of a testparticle, motion of a body around a gravitative central body, Einstein effects, time dependence of the "effective gravitational constant" etc. Further, this theory predicts heat production by the cosmological expansion in a moving body. Numerical results are presented for orbiting stars, planets, moons, satellites and terrestrial bodies.     

On the initial expansion of meteor trails

The asymptotic solution of the equation governing the number density n(r,t) of evaporated meteoric atons behind a steadily moving meteor is obtained which is suitable to depict the initial expansion of a meteor trail. Some unusual results of meteor observations are elucidated.     

HESS observations of the galactic center region and their possible dark matter interpretation

The detection of gamma rays from the source HESS J1745-290 in the Galactic Center (GC) region with the High Energy Spectroscopic System (HESS) array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse gamma-ray emission from the GC ridge, the source is compatible with a point source with spatial extent less than 1.2;{'}(stat) (95% C.L.). The measured energy spectrum above 160 GeV is compatible with a power law with photon index of 2.25+/-0.04(stat)+/-0.10(syst) and no significant flux variation is detected. It is finally found that the bulk of the very high energy emission must have non-dark-matter origin.     

A new interpretation of Bell's inequalities

Bell's inequalities are always derived assuming that local hidden-variable theories give a set of positive-definite probabilities for detecting a particle with a given spin orientation. The usual claim is that quantum mechanics, by its very nature, cannot produce a set of such probabilities. We show that this is not the case if one allows for generalized (nonpositive-definite) master probability distributions. The master distributions give the usual quantum mechanical violation of Bell's inequalities. Consequences for the interpretation of quantum mechanics are discussed.     

A new interpretation of time reversal

A new interpretation of the time-reversal invariance principle is given. As a result, it is shown that microscopic dynamic reversibility has no basis in physics. The existing contradiction between one-way time and two-way time is reconciled. It is also pointed out that the common notion that clocks run backwards when time is reversed is wrong.     

A new interpretation of Vaidya radiation

If Vaidya radiation is taken to be a combination of an electromagnetic energy flux together with that of a null fluid it is shown that the singularity in the current density along an axis, which arises in the absence of a null field, is removed.     

A new interpretation of the special theory of relativity

Assuming the “Big Bang” theory as well as the usual axioms in the Special Theory of Relativity, the time dilations and length contractions are treated as real physical effects. This becomes possible by relating everything to the hypothetical frame,S _a , at rest relative to the “Big Bang” event. This frame in many senses plays the role of the classical aether frame. A clock's real ryhthm, as opposed to its rhythm observed by restricted methods, is then a function of its velocity relative toS _a (assuming a uniform gravitational field). It is further assumed that gravitational radiation is composed of “electromagnetic-like” waves. Therefore when a clock changes its velocity in a uniform gravitational field it must receive a different total energy due to the average frequency shift (Doppler effect), the time dilations are then caused by the change in energy due to this frequency shift. That is, not wo clocks can be in the “same” gravitational field unless they have no relative velocity, and therefore the Special Theory of Relativity is a special case of the General Theory from this viewpoint. Two feasible experimental tests, using the Mössbauer effect, are described that would decide on these viewpoints. The principle of equivalence and the “twin paradox” are also discussed.