从形体到整体——论亚里士多德《论天》Ⅰ.1对自然研究一般方法的实践

《论天》Ⅰ.1将大量篇幅集中在对“体”以及相关概念的分析和讨论。传统解释将这一章中亚里士多德对作为量的“体”或形体的讨论仅理解为他对作为自然研究对象的“体”或物体的阐发,却忽视了这一讨论在《论天》Ⅰ.1中更根本的作用,即它不但能够引导读者设想并逐渐接受一个不易为我们所理解的宇宙整体概念,为他接下来的宇宙论研究奠基,同时也是对他自然研究一般方法的实践。《论天》Ⅰ.1在亚里士多德宇宙论研究中具有落实其自然研究一般方法以及为其宇宙论研究进行概念准备和视野转换的双重意义。

严译《天演论》与叶尔恺、吴汝纶

严复在中国思想文化史上的地位,主要是通过《天演论》翻译,向中国人介绍了进化论思想奠定的。由于知识结构、时代因素,严复的翻译并不是一气呵成,更不是一蹴而就,而是一个缓慢过程。在那知识饥渴的年代,《天演论》自然形成了几个不同的版本。叶尔恺、吴汝纶等对《天演论》传布、定稿,都有不同贡献。

浑天说数理模型的构建尝试与失败——以祖暅《浑天论》为中心

文章重点考证了汉魏以来400年间浑天说数理模型的构建过程。张衡首先对浑天说进行数理描述,但是他的数据缺少测算依据。王蕃基于古代测算原理给出“天高数”和“周天里数”,不失为一次有效的数理探索。祖暅认同王蕃的两个数据和方法,同时补充了冬至、春秋分的相关数据及北极高数等。基于此,笔者尝试复原浑天说数理模型。文章讨论了祖暅应用他的浑天模型解释日月直径关系、四季寒暑成因、测地中之法等的原理,其中不乏个人创造和模型严谨化的趋势。祖暅及其先人的构建尝试与思想实践非常可贵,但是由于其依据“日影千里差一寸”旧制以及王蕃“天高数”遭到一行否定,浑天说数理模型的探索最终以失败而告终。

The correction of diurnal effects on CSTAR photometry

In January, 2008 the Chinese Small Telescope ARray （CSTAR） was suc-cessfully deployed at Dome A, Antarctica. Because CSTAR consists of four static14.5 cm telescopes pointing at the same 4.5° x 4.5° field around the south celestialpole, diurnal motion can be seen in its field of view. The stars are centered at differentpositions in different exposure frames. During four months of continuous observationsduring the polar night of 2008, about 0.3 million/-band images were obtained. In thelatest version of the released photometric catalog, the effects of diurnal motion of thestars on the static CSTAR optical system can be obviously found. In this work, weupdate the CSTAR catalog by carefully analyzing and correcting the systematic errorscaused by diurnal motion of stars on imperfectly flat-fielded frames.

Spacecraft Doppler tracking with possible violations of LLI and LPI: a theoretical modeling

Currently two-way and three-way spacecraft Doppler tracking techniquesare widely used and play important roles in control and navigation of deep space mis-sions. Starting from a one-way Doppler model, we extend the theory to two-way andthree-way Doppler models by making them include possible violations of the localLorentz invariance （LLI） and the local position invariance （LPI） in order to test theEinstein equivalence principle, which is the cornerstone of general relativity and allother metric theories of gravity. After taking the finite speed of light into account,which is the so-called light time solution （LTS）, we make these models depend on thetime of reception of the signal only for practical convenience. We find that possibleviolations of LLI and LPI cannot affect two-way Doppler tracking under a linear ap-proximation of LTS, although this approximation is sufficiently good for most cases inthe solar system. We also show that, in three-way Doppler tracking, possible violationsof LLI and LPI are only associated with two stations, which suggests that it is betterto set the stations at places with significant differences in velocities and gravitationalpotentials to obtain a high level of sensitivity for the tests.

A possible precessing nozzle and the Lense-Thirring effect in blazar 3C 454.3

The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included： superluminal knots R1, R2, R3, R4, A, B, C and D（from Britzen et al. 2013） and C4 （from Pauliny-Toth 1998）. We find that their kine-matics derived from VLBI observations can be consistently interpreted in terms of ajet precession scenario with a period of about 14.5 yr. We discuss the model fits oftheir trajectory, distance from the core and apparent velocity. We show that the bulkLorentz factor （in the range 4 to 15） derived for these components does not have anydependence on the phase of the precession （or position angle for ejection）. The Lense-Thirring effect is assumed to interpret the precession of the jet nozzle. The resultsobtained for blazar 3C 454.3 are only suggestive. They are not unique and have yet tobe tested, but they might be useful for understanding the kinematics of superluminalcomponents in blazars and for disentangling different mechanisms and factors.

Observations of counter-propagating Alfvénic and compressive fluctuations in the chromosphere

Recent observations have found that chromospheric spicules behave likeAlfvenic fluctuations. Low-frequency Alfven waves are predicted to partially reflectin the transition region that has a gradient in the Alfven speed, thereby producinginward Alfven waves, which may interact nonlinearly with outward Alfven wavesto generate Alfv6nic turbulence. However, the signature of Alfvenic turbulence in thechromosphere has not yet been quantitatively analyzed with observations. Here we an-alyze some characteristics related to Alfv6nic turbulence with the observations fromHinode/SOT. We decompose the height-time diagram of the transverse oscillationsto separate the outward and inward propagating Alfvenic-like signals. The counter-propagating waves are found to have similar amplitude, period and phase speed, sug-gesting a state having an approximate balance in bi-directional energy fluxes. Counter-propagation of intensity oscillation with lower propagation speed is also presented,probably indicating the presence of slow mode waves. Moreover, we attempt to esti-mate the Elseisser spectra of the chromospheric turbulence for the first time. The rela-tive fluctuations in the magnetic field may be measured as the local slope of wave-likeshapes in spicules. The resulting low-frequency Elsaisser power spectra look similarto each other without showing a dominant population, which confirms these counter-propagating low-frequency Alfv6nic waves are in a state of balanced flux. These obser-vational results are believed to help us better understand the nature of chromosphericturbulence as well as chromospheric heating.

Reduced transition probabilities for 4He radiative capturereactions at astrophysical energies

The reduced transition probabilities from an electric quadrupole B（E2） andreduced transition probabilities from a magnetic dipole B（M1） between the groundstate and the first excited state have been calculated for the 3He（α,γ）7Be, 8Be（α,γ）12cand 12C（α,γ）160 radiative capture reactions with the M3Y potential. These reactionsare important in stellar evolution. The calculated B（M1） and B（E2） for 7Be nuclei arefound to be 1.082 x 10-3 e2 fm2 and 1.921 e2 fma from transitions 3/2- to 1/2-, re-spectively. The obtained values for reduced transition probabilities B（E2） for the 12Cand 160 nuclei from transitions 0＋ to 2＋ are 12.54 e2 fm4 and 14.18 e2 fm4, respec-tively. The results are in satisfactory agreement with available experimental data.

Comparison of three filters in asteroid-based autonomous navigation

At present, optical autonomous navigation has become a key technologyin deep space exploration programs. Recent studies focus on the problem of orbit de-termination using autonomous navigation, and the choice of filter is one of the mainissues. To prepare for a possible exploration mission to Mars, the primary emphasisof this paper is to evaluate the capability of three filters, the extended Kalman filter（EKF）, unscented Kalman filter （UKF） and weighted least-squares （WLS） algorithm,which have different initial states during the cruise phase. One initial state is assumedto have high accuracy with the support of ground tracking when autonomous navi-gation is operating; for the other state, errors are set to be large without this support.In addition, the method of selecting asteroids that can be used for navigation fromknown lists of asteroids to form a sequence is also presented in this study. The simula-tion results show that WLS and UKF should be the first choice for optical autonomousnavigation during the cruise phase to Mars.

Isospin violation in the d（n,γ）3Hprocess at energies relevant forbig bang nucleosynthesis

The cross section for a neutron-deuteron （nd） radiative capture is calcu-lated using the pionless effective field theory including isospin symmetry breaking（ISB） corrections up to higher order. The triton is studied as a three-body bound stateand one has to take into account various ISB effects, relativistic corrections and ex-ternal electromagnetic currents. The isospin violation in nd radiative capture is im-proved compared to the one at NLO and N2LO. The cross section is determined to beσtot = [0.505 ± 0.003] mb up to N2LO. A satisfactory agreement between theory andexperiment for the calculated cross section has been found by insertion of three-bodyforces and ISB effects.

Formation of cyanoallene(buta-2, 3-dienenitrile) in the interstellar medium: a quantum chemical and spectroscopic study

The interstellar medium, filling the vast space between stars, is a rich reser-voir of molecular material ranging from simple diatomic molecules to more com-plex, astrobiologically important molecules such as vinylcyanide, methylcyanodiac-cetylene, cyanoaUene, etc. Interstellar molecular cyanoallene is one of the most stableisomers of methylcynoacetylene. An attempt has been made to explore the possibilityof forming cyanoallene in interstellar space by radical-radical and radical-moleculeinteraction schemes in the gaseous phase. The formation of cyanoallene starting fromsome simple, neutral interstellar molecules and radicals has been studied using densityfunctional theory. The reaction energies and structures of the reactants and productsshow that the formation of cyanoallene is possible in the gaseous phase. Both of theconsidered reaction paths are totally exothermic and barrierless, thus giving rise to ahigh probability of occurrence. Rate constants for each step in the formation processof cyanoallene in both the reaction paths are estimated. A full vibrational analysishas been attempted for cyanoallene in the harmonic and anharmonic approximations.Anharmonic spectroscopic parameters such as rotational constants, rotation-vibrationcoupling constants and centrifugal distortion constants have been calculated.

Non-thermal emissions from accreting X-ray binary pulsars

We study non-thermal emissions from cascade processes in accreting X-raybinary pulsars. In the framework of the magnetospheric gap model, we consider threephoton fields, which are respectively from the polar cap of a pulsar, its surroundingaccretion disk and a massive companion star with a circumstellar disk, to shield thegap. The gap-accelerated ultra-relativistic electrons emit high-energy photons via cur-vature radiation and an inverse Compton scattering process, in which part of thesehigh-energy photons absorbed by interactions with the surrounding photon fields canfacilitate the following electromagnetic cascades. We first carry out numerical calcula-tions of the cascade processes in order to obtain the predicted emission spectra. As anexample, we subsequently apply this model to reproduce observations of LS I ＋61~303. We find that the results can fit observations ranging from hard X-ray to γ-raybands, In particular, they can explain the spectral cutoff feature at a few GeV. Finally,we suggest that the emissions detected by the Fermi Large Area Telescope from X-raybinary pulsars originate in the magnetosphere region of the pulsar.

Detection of large color variation in the potentially hazardous asteroid(297274) 1996 SK

Low-inclination near-earth asteroid （NEA） （297274） 1996 SK, which isalso classified as a potentially hazardous asteroid, has a highly eccentric orbit. Itwas studied by multi-wavelength photometry within the framework of an NEA colorsurvey at Lulin Observatory. Here, we report the finding of large color variationacross the surface of （297274） 1996 SK within one asteroidal rotation period of4.656 ± 0.122 hours and classify it as an S-type asteroid according to its averagecolors ofB - V = 0.767 ± 0.033, V - R = 0.482 ± 0.021, V - I = 0.801 ± 0.025and the corresponding relative reflectance spectrum. These results might be indica-tive of differential space weathering or compositional inhomogeneity in the surfacematerials.

近10年《素问·上古天真论》相关研究知识图谱分析

目的通过知识图谱方式可视化分析《素问·上古天真论》相关研究的热点和趋势。方法以"上古天真论"为研究对象,检索2006年1月至2017年1月中国知网(CNKI)中国学术期刊数据库中相关研究。分别对纳入数据以作者、机构、关键词为节点进行可视化,并对其出现频次进行统计。结果共纳入数据857条。2006年至2017年发表关于《素问·上古天真论》研究的作者共有72人,作者频次前5名为吴效科(7)、孙广仁(5)、侯丽辉(5)、张新渝(5)、王泓午(4),突现度前5名为吴效科(5.3995)、侯丽辉(3.7747)、王琦(2.8911)、王泓午(2.6971)、孙广仁(2.6701)。发文量前5的研究机构分别为山东中医药大学(29)、北京中医药大学(27)、上海中医药大学(23)、成都中医药大学(18)、广州中医药大学(14)。关键词共现网络图谱共169个节点、318条连线,其中频次前5名为黄帝内经(347)、上古天真论(171)、养生(121)、中医(74)、治未病(66),中心度前5名为上古天真论(0.64)、黄帝内经(0.58)、养生(0.46)、中医(0.18)、生气通天论(0.16)。关键词共现聚类结果可分为9类,各类中频次最高的关键词分别为0:中医,治未病;1:黄帝内经;2:上古天真论;3:肾气盛,天癸;4、6:养生;5、7、8:素问,肾气。结论近10年《上古天真论》研究作者和研究机构合作力量较分散,2014年以来经验传承研究成为新的热点,研究趋势从原文发掘应用趋向于更深层次的理论实践研究。