太阳物理研究进展

简要地介绍了太阳物理学研究的内容、方法和目标，着重评述了近年太阳物理学的研究进展，包括中国太阳物理研究的现状和成就，指出未解决的主要科学问题和进一步工作的方向．     

西藏日食太阳辐射观测研究

日食现象会对地球太阳辐射、大气气象以及人类活动等造成相应的影响。2020年6月21日（夏至）在西藏发生了一次日食现象,西藏阿里日环食最大食分达到了0.995,拉萨地区日偏食食分也高达0.953。两地日食均发生在当地正午前后。本研究利用罕见的日食出现机会,对西藏阿里和拉萨日食过程中的太阳光谱、太阳总辐射和太阳紫外线变化特征进行了同步观测研究。观测表明阿里日环食在当地正午（北京时间14:41分）前后持续了约3小时27分钟;拉萨日食出现时间比阿里滞后约26 min,持续时间比阿里短3分28秒。实地观测表明在日食期间,阿里光谱观测中最强单色（476.6 nm）光峰值从初亏（13:01分）时刻的1 669.234 mW·m-2·nm-1陡然衰减到食甚（14:44分）时刻的61.936 mW·m-2·nm-1,损失约96.0%;相应时刻太阳总辐射强度从1 221.217 W·m-2衰减到56.086 W·m-2,也损失约95.4%。拉萨日食期间最强单色（476.6 nm）光峰值从初亏（13:27分）时刻的1 563.876 mW·m-2·nm-1亏损到食甚（15:13分）时刻的26.391 mW·m-2·nm-1,亏损约98.3%;相应时刻太阳总辐射强度从1 605.663 W·m-2衰减到28.169 W·m-2,也亏损约98.2%。观测研究发现拉萨太阳紫外线B剂量率从初亏的60.8 W·m-2减弱到食甚的0.9 W·m-2值,减弱了98.5%。该次日食对西藏地面各种太阳辐射强度造成95%以上能量损失。     

天然矿物合成“中国紫”过程中的变温XRD分析

以天然矿物为原料,结合中国紫的分子式及多数考古样品的分析结果进行配料(如或多或少都含有铅),对配制并加工好的试样进行热重-差热及变温XRD分析,以探讨古代烧制中国紫颜料时的原料选用及烧制条件等问题,为揭示诸如中国紫产生在中国的原因等问题提供依据。结果表明利用毒重石(BaCO3)配料,能够较容易地烧制出中国紫,这意味着中国紫的出现可能与这种独特的含钡矿物资源有关。     

Long term variations of solar radius

Total and annular eclipses allow us to measure the angular solar diameter at unit distance up to an accuracy of some hundredths of arcsecond. Data of lunar limb features from Japanese mission Kaguya will be useful to detect also the solar oblateness signal, relevant from a General Relativistic point of view. Useful eclipse data are available for 1567, 1715, 1869, 1925 and from 1966 to 2009 with uneven sampling: only these data can allow a study of solar diameter evolution with significant resolution on secular basis.     

Guidelines for measuring solar radius with Baily beads analysis

By inspection of central eclipses videorecords, data of Baily beads timings are retrievable. Knowing the lunar limb profile at the moment of the eclipse we evaluate the excess or defect of solar limb when the Sun is assumed at its standard radius. Two procedures of data analysis are here presented: one based on limb heights and the other on times. While these methods are based upon Occult 4 software, they can be used with other ephemerides and new lunar profiles. The example of 2006 total eclipse data, with its remarkably negative value of ΔR= − 0.41“± 0.04”, is presented.     

Effect of solar eclipses on neutron flux variations at the Earth’s surface

The results of the investigation of the neutron flux variations at the Tien Shan high-altitude scientific station during solar eclipses on September 23, 1987; August 11, 1999; and March 29, 2006 are reported. It is established that, during these periods, the dynamics of neutron intensity variations in the frequency range 10^?5–10^?3 Hz is due to geophysical sources of disturbances. An increase in the thermal neutron flux from the Earth’s Crust is observed.     

Amazonia Introduced to General Relativity: The May 29, 1919, Solar Eclipse from a North-Brazilian Point of View

In 1919, A. C. D. Crommelin and C. R. Davidson, British astronomers from the Greenwich Observatory in England, passed by Amazonia on their Brazilian journey aiming to measure the bending of stars' light rays during the total solar eclipse of May 29, 1919, and thereby put the theory of general relativity to the test. In the context of Crommelin’s and Davidson’s visit, we discuss how Amazonia was introduced to Einstein’s theory of gravitation, and also the observations and repercussions of the May 29, 1919, solar eclipse in Belém, capital city of the North-Brazilian Pará state.     

Pulsar NP-0532-A “Spectroscopic” Binary?

In November, 1967, the first pulsar was discovered by Antony Hewish of Cambridge University. Within a year a dozen more were discovered. They may be described as radio sources within the Milky Way Galaxy that emit pulsed radio signals. Very little else is known about them with certainty, although most astronomers believe they are probably neutron stars. The mechanism by which they emit radio signals is unknown.     

Weighing Photons,I

For over fifty years astronomers sought inconclusively to confirm Albert Einstein's prediction of a "gravitational red shift" by studies of solar and stellar spectra. Although it was expected by the 1950s that the combination of atomic clocks with vehicles sent into space would finally enable a conclusive test, the development of precise examples of the resonant absorption of gamma rays between nuclei bound in solids, discovered by Rudolf Mössbauer in 1958, provided a basis for an experiment within an earthbound laboratory. I describe the trials and tribulations of making the necessary extension of the phenomenon, including the discovery of the unanticipated effect of temperature as causing relativistic time dilation, that led to a successful confirmation in March of 1960 of a shift amounting to only 2.5 2 10^⪣ to less than a 10% uncertainty.     

Chemical Analyses of Potash–Lime Silicate Glass Artifacts from the Warring States Period in China

Potash–lime silicate (K₂O–CaO–SiO₂) glass dated to the Warring States Periods is one of the earliest glass types that have been found in China, but scientific research about this type of glass is scarce at home and abroad. In the present study, a total of 23 potash–lime silicate glass samples of the Warring States Period, excavated from different areas of China, were analyzed noninvasively using a portable X-ray fluorescence spectrometer (pXRF). The chemical composition of these K₂O–CaO–SiO₂ glasses was analyzed and compared with that of the potash silicate (K₂O-SiO₂) glasses of the Han Dynasties. The possible raw materials used to make the ancient K₂O–CaO–SiO₂ glasses were discussed. It appears that the ancient K₂O–CaO–SiO₂ glasses were produced in China and the potash glasses were of versatile origins. This research provides useful clues to trace the technical development of ancient Chinese glass.     

3D Modeling of the solar corona in different stages of the solar magnetic cycle over the period 1870 to 1991

Three-dimensional (3D) modeling of the solar corona has been carried out on the basis of the magnetic field distribution on H-alpha charts for the epochs of solar eclipses that occur near the epoch of the polar magnetic field reversal. Analysis of the 3D modeling shows that:

1. Besides the global neutral sheet, two high-latitude coronal neutral sheets are also observed during the epoch of the polar magnetic field reversal.
2. The observed structure of the coronal streamers is due to a projection of the folds of corrugated neutral sheets on the picture plane rather than due to the peculiar configuration of the magnetic field lines.

     

水热制备中国紫BaCuSi2O6的条件探索及各条件产物分析研究

中国紫BaCuSi₂O₆是中国古代人工颜料硅酸铜钡的一种，是中国古代科技史中独树一帜的文明成果，代表了当时中国的科技水平和科技成就。水热合成法通过高温高压的水蒸气使那些在大气条件下不溶或难溶的物质溶解，并且重结晶来进行无机合成与材料处理，是近年来比较新兴的方法。参考前人研究，采用水热合成法，选择BaCl₂·2H₂O，CuO，Na₂SiO₃·9H₂O为原料，按照目标产物化学计量比称取，调控溶液pH、合成温度和保温时间等影响因素，制备出高纯度的中国紫。产物的物相与纯度使用XRD表征。实验结果表明，当10≤pH≤12时可生成纯度较高的中国紫，160 ℃时生成的中国紫纯度较180 ℃更高，且随着水热时间的延长，中国紫的纯度提高。考虑到绿色安全、能耗低、操作简便等因素，最终得出水热制备中国紫的最佳制备条件是pH 12，温度为160 ℃，保温时间48 h。中间产物BaSi₂O₅和Ba₄Si₆O₁₆的发现，表明在硅酸铜钡晶体的生长过程中Ba与Si先与O以不同形式结合，Cu最后参与构筑硅酸铜钡晶体。该工作提供了一种新方法用于合成纯净中国紫，可用来做文物保护修复材料；同时在中国紫的合成机理研究方面提供依据和线索，对中国古代科技史研究具有促进作用。     

Scientific analysis of some glazed pottery unearthed from Warring States Chu tombs in Jiangling,Hubei Province: Indication for the origin of the low-fired glazed pottery in China

A portable energy dispersive X-ray fluorescence spectrometer and a micro-Raman spectrometer are used for the nondestructive analysis of a batch of glazed pottery ornaments unearthed from Warring States Chu (楚) tombs (B.C.475–B.C.221) in Jiangling, Hubei Province, China. According to the chemical compositions obtained, all of the glazes belong to the lead–barium–silicate (PbO–BaO–SiO₂) system and contain certain levels of copper. The man-made barium copper silicate pigment crystals, such as Chinese blue (BaCuSi₄O₁₀) and Chinese purple (BaCuSi₂O₆), are identified from several samples by micro-Raman spectrometer. Besides, gypsum and hematite are found in the white and brown regions of two eye beads. Combined with other glazed pottery and the related silicate artifacts (e.g., lead–barium glass and faience, potash–lime glass and glazed pottery, high-lead glazed pottery, etc.), the origin, development, and affected factors of ancient Chinese low-fired glazed pottery have been discussed preliminarily. The present study provides principal evidences for the technological provenance, raw material recipes, and the relationship between low-fired glazed pottery and related vitreous materials of ancient China. It also provides some significant clues for the origin and the development of ancient Chinese lead–barium glass.     

河南宝丰和新郑出土硅酸盐制品的无损分析研究

无损分析是文物样品研究的重要内容,研究中采用便携式能量色散型X射线荧光光谱仪(pXRF)和激光拉曼光谱仪(LRS),对河南宝丰和新郑出土的21件战国晚期到汉代的硅酸盐制品进行了化学成分分析和微区物相分析。依据化学成分分析结果,将样品划分为铅钡硅酸盐玻璃、钾硅酸盐玻璃、釉砂和铅钡釉砂四类分别进行讨论,并对样品的着色机理进行了初步探讨;利用激光拉曼光谱在部分蜻蜓眼和圆环珠蓝色颜料中检测到了中国蓝(BaCuSi₄O₁₀)、中国紫(BaCuSi₂O₆)和中国深蓝(BaCu₂Si₂O₇),同时成功确定了部分样品中存在石英、方解石、碳酸铅、煅棕土、绿土等多种物相;结合考古研究资料,对这些样品的来源进行了简要讨论,其中本实验铅钡硅酸盐玻璃、钾硅酸盐玻璃耳珰和铅钡釉砂为我国自制,而另外1件釉砂可能属于舶来品,反映了我国古代中原各地区间,以及中原与西域间有着广泛的文化技术交流。便携式能量色散型X射线荧光光谱仪和激光拉曼光谱仪的相互结合,能够提供硅酸盐制品的有效化学成分和结构信息,在文物科学分析中显示出特有的优势,为其考古研究提供有益的信息。     

Spectral analysis of two solar twins and the colors of the Sun

High resolution (R~40,000) and high signal-to-noise ratio (150) spectra of two solar twins, HD146233 and HD195034, are obtained with the Coude Echelle Spectrograph at the 2.16 m telescope of the National Astronomical Observatories of Chinese Academy of Sciences (Xinglong, China). Based on the detailed spectrum match, comparisons of chemical composition and chromospheric activity, HD146233 and HD195034 are confirmed that they are similar to the Sun except for lithium abundance, which is higher than the solar value. Moreover, among nine solar twin candidates (including HD146233 and HD195034) found in the previous works, we have picked out six good solar twin candidates based on newly-derived homogenous parameters, and collected their colors in the Johnson/Cousins, Tycho, 2MASS and Strmgren system from the literature. The average color are (B-V)⊙=0.644 mag, (V-Ic)⊙=0.707 mag, (BT-VT)⊙=0.725 mag, (J-H)⊙=0.288 mag, (H-K)⊙=0.066 mag, (v-y)⊙=1.028 mag, (v-b)⊙=0.619 mag, (u-v)⊙=0.954 mag and (b-y)⊙=0.409 mag, which represent the solar colors with higher precision than previous works.     

Atmospheric aerosol limb scanning based on the lunar eclipses photometry

The work is devoted to the analysis of the surface photometric observations of two total lunar eclipses in 2004. The lunar surface relative brightness distribution inside the umbra was used to retrieve the vertical distribution of aerosol extinction of the solar radiation expanding by a tangent path and its dependence on the location at the limb of the Earth. The upper altitude of troposphere aerosol layer was estimated for different latitude zones. The correlation between additional aerosol extinction in the upper troposphere and cyclones was investigated.     

浙江古城墙传统灰浆材料的分析研究

灰浆材料一直是古代建筑类文化遗产研究的重要对象,文保工程中使用传统灰浆的诸多优点已广为人知,在认识传统灰浆的基础上开发新的石灰基粘结保护材料已然成为国际研究热点。随着中国的经济发展,很多古建筑的保护也开始提上日程,然而关于中国传统灰浆材料的研究颇为薄弱。实地调查浙江地区多座古代城墙遗址,采集灰浆样品,利用多功能密度仪、粉末X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)、热重-差热分析仪(TG-DSC)和湿化学分析技术,对浙江地区7处古城墙灰浆样品进行了分析检测和研究。结果表明：这些古城墙使用的胶结材料是纯“白灰灰浆”,主要成分是碳酸钙,含量在75%～90%之间,其原料主要是钙质生石灰,个别来自镁质生石灰;其中有4座城墙灰浆添加有糯米成分,说明该地区在明代向灰浆里添加糯米等有机材料是建筑城墙十分普遍的工艺技术;检测发现这些建筑灰浆的密度较低,且数值相差较大,在1.2～1.9 g·cm-3之间,应是环境长期侵蚀的结果。同时,也分析了这些砌筑灰浆的其他物化特征,为下一步古城墙本体保护和保护材料的研发,以及传统灰浆全国范围内的比较研究提供了科学依据。     

Enhanced photon harvesting in silicon multicrystalline solar cells by new lanthanide complexes as light concentrators

Four europium complexes with enhanced luminescent properties have been synthesized. Thin transparent films of the complexes were prepared on glass panes and then were examined as efficient luminescent solar concentrators for full spectrum utilization in crystalline silicon photovoltaic cells. The complexes could behave as efficient solar concentrators since they absorb UV light, where the spectral response of the crystalline silicon solar cells is low and they emit at 615 nm where the spectral response is maximum. The glass panes covered with europium complexes act as planar waveguides of the emitted light that is collected by the solar cells, which are attached to the edges of the solar concentrators. The europium complexes as solar concentrators were examined in terms of the optimum concentrations and the number of coatings, which were determined in order to evaluate the maximum performance of the solar cells. The case of multiple glass panes with europium complexes was also examined while a 28% maximum increase in the photocurrent was finally established.     

马家塬M21出土一件料珠的成分和风化层的研究

为研究古代人造料珠的成分和风化状况,对马家塬M21墓地内出土的一件料珠进行超景深显微观察,扫描电镜能谱分析（SEM-EDS）与拉曼光谱分析（Raman）,观察了样品表面形态、获得了样品元素组成和物相组成。结果揭示料珠主要组成成分为混合BaSO₄,PbCO₃,Pb₅Si₄O₈(OH)₁₀和Cu₂Pb₅(SO₄)₃(CO₃)(OH)₆等杂质的中国蓝,呈现为浅蓝色颗粒,由固相烧结法制作,外部黄色结壳成分为Pb₈O₅(OH)₂Cl₄。研究阐述了中国蓝工艺的发展及风化生成碱性铅化合物的原因,该料珠的元素分析显示Si含量最高,Cu和Ba的含量大略相等,而Pb的含量较低,可能代表当时硅酸铜钡料珠烧制已经开始有意控制原料的比例;碱性铅化合物应是在埋藏过程中形成的,高温烧结制备料珠时产生的氧化物未反应完全,随后被埋入地下,与碱性土壤水水合形成碱性铅化合物。该研究为古代费昂斯制品和硅酸铜钡类制品的研究提供参考,对中国古代科技史研究具有重要意义。     

The cavendish laboratory—aristocrat's playground to people's workshop

Positional astronomers require a reference frame to which they can refer their observations, and which can be related, at any instant, to an inertial reference frame through dynamical theory. The exect definition of the celestial pole is of considerable practical importance, in order that proper allowance can be made for short period oscillations of observatory coordinates, and to avoid discontinuity in the reference frame as theories of the Earth's rotation are improved.

In this article the principles underlying the measurement of celestial coordinates are described, from the point of view of optical astrometry, and various complexities affecting the optimum definition of the ‘ephemeris reference frame’ are discussed.