红外光谱和拉曼光谱在热处理海蓝宝石鉴定中的应用

在适当的热处理条件下,黄绿色绿柱石能够转变为理想颜色的海蓝宝石。天然海蓝宝石与热处理海蓝宝石的价格差异较大,因此探索热处理海蓝宝石的诊断性鉴定特征就显得十分必要。对不同温度下热处理海蓝宝石进行傅里叶变换红外光谱和激光拉曼光谱的测试分析,结果发现,当热处理温度超过400℃后,随着加热温度的升高,在红外光谱中由[Fe2（OH）4]2＋伸缩振动gI起的3233cm叫处吸收谱峰明显减弱,直至消失。5268cm叫附近由水伸缩和弯曲振动}I起合频区的吸收带由尖峰变得宽缓;8700,6818cm叫两处水吸收峰的相对强度也随着加热温度升高而减弱。热处理海蓝宝石Si-0-Si伸缩振动产生的在682,3604cm叫处的拉曼光谱谱峰强度随着加热温度升高逐渐减弱,1070cm“处的拉曼峰强度明显降低。经700℃加热后,拉曼光谱基线明显向上方漂移。这些光谱特征变化对热处理海蓝宝石的鉴定有重要意义。     

Observations of cyanoacetylene sources

Thirty-four Galactic star-forming regions have been observed in the J=4?3 line of cyanoacetylene (HC₃N) at 36.4 GHz. Emission was detected toward 17 sources. The HC₃N column density was determined in the detected sources, and in eight of them (NGC 2264, L379, W51E1/E2, DR 21 West, DR 21 (OH), DR 21, S140, and Cep A), the relative cyanoacetylene abundance was estimated. The HC₃N abundance in these objects is about 1–70×10^?10.     

双出口旋流取样器在RC钻探试验中的应用

反循环取样（RC）钻探是钻探技术的又一次技术革命,以其高效率、低成本、高适应性在西方国家得到了广泛应用。近年来,RC钻探在我国也越来越得到重视,应用越来越多。采样工艺是RC钻探的重要组成部分,国外在这方面比较先进,而我国采样工艺相对简单落后。双出口旋流取样器是对单出口旋流取样器的改进,在单出口的基础上增加了一个出口及阀门,阀门为两个出口共用,开启一个的同时关闭另一个。通过阀门的开关实现两个出口轮流接样,避免了连续进尺情况下的样品遗漏,减少了取样过程中粉尘外溢造成的污染。通过在卡拉塔格整装勘查区RC钻探试验中的应用,证明了它在防止样品遗漏、减少环境污染及便利取样操作方面有很大优越性。     

A study of radio sources using interplanetary scintillations at 111 MHz. Core-dominated sources

A complete sample of core-dominated radio sources has been studied using the interplanetary-scintillation method. In total, 72 sources were observed, with scintillations detected in 28 of them. The remaining sources have upper limits on their flux densities. Integrated flux densities are estimated for 24 sources. Cut-offs have been observed in the spectra of many sources. The thermal-electron densities have been estimated, assuming that these cut-offs are due to free-free absorption of the synchrotron radio emission.     

应用傅里叶变换红外光谱与紫外可见吸收光谱鉴别两类海水养殖灰色珍珠

Akoya珍珠属生物矿化有机宝玉石,该类珍珠的矿物组成与微结构分析、定性与其颜色形成属性的鉴定方法尚为缺乏。本文通过光学显微镜、紫外可见吸收光谱、傅里叶变换红外光谱、能量色散X射线荧光光谱对具有白色或灰色珠核的两类Akoya灰色珍珠的珍珠层与珠核的结构特征及显色机制、紫外吸收光谱、微量金属元素赋存特征进行了对比研究。结果表明:①灰色珍珠的珠核有白色与灰色两类,两类珍珠的直径主要分布在5～9mm,珍珠层厚度约300～500μm;②两类珍珠的珍珠层和珠核的主体矿物组成均为生物文石,且两者的珍珠层中均富Sr贫Mn。③灰色的珠核具有明显的富Mn特征,且由于辐照使得Mn元素的价态升高并使得珠核致灰色,并导致整个珍珠呈现灰色;④紫外可见吸收光谱检测中,一般而言具有白色珠核的灰色珍珠在300～400nm波段可见明显的反射带,而具有灰色珠核的灰色珍珠在400～500nm波段可见明显的反射带。两类灰色珍珠皆为海水养殖珍珠,研究表明这两类珍珠的紫外吸收光谱的差异可作为初步评判灰色系珍珠是否经辐照改色的依据之一。     

A Calculation Model for Corrosion Cracking in RC Structures

A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of the rust layer is established. By deducing the radial displacement expression of concrete, the formula for corrosion depth and corrosion pressure before cracking is proposed. The crack depth of cover in accordance with the maximum corrosion pressure is deduced; furthermore, the corrosion depth and corrosion pressure at the cracking time are obtained. Finally, the theoretical model is validated by several experiments, and the calculated values agree well with the experiment results.     

Studies of weak compact radio sources

Approximately 20% of weak sources in a scintillation survey at 102 MHz were not identified in other, more sensitive, low-frequency surveys. These sources had very high compactness and steep spectra. Since, as shown earlier, these sources are probably quasars, the epoch of the radio birth of quasars should correspond to flux densities of ～0.01 Jy.     

Studies of bright steep-spectrum radio sources

Results of studies of bright radio sources in the constellation Cetus are presented. More than 50% of the sources have radio spectral indices steeper than 0.9. Optical identifications have been determined for 35 sources. A large fraction of the radio sources are identified with weak blue galaxies. Given their spectral indices, it is likely that these objects have redshifts z=0.4–1.0. More than 20% of the steep-spectrum sources do not have optical identifications and appear to be weak galaxies with z>2.     

上房沟钼矿辉钼矿俄歇能谱分析

通过扫描电镜分析和俄歇能谱分析对上房沟钼矿原矿、浮选精矿和浮选尾矿以及三道庄钼矿(易选矿)中辉钼矿进行了表面元素组成和微形貌研究。结果显示上房沟钼矿中辉钼矿表面呈陡峭阶梯状,且氧化强烈,而三道庄钼矿中辉钼矿表面平整,氧化较弱。综合分析认为上房沟钼矿中辉钼矿陡峭阶梯状表面会增加其表面极性面的比重;表面氧化会增加辉钼矿表面非极性面的表面能,改变其表面疏水性。两者都会降低辉钼矿的可浮性。因此上房沟钼矿中辉钼矿表面氧化程度高、表面不平整是影响其浮选效果的主要因素之一。     

Spectroscopy of red dravite from northern Tanzania

Low-Fe dravite with a formula of Na_0.66Ca_0.16Mg_2.62Fe_0.33Mn_0.02Ti_0.02Al_5.95B₃Si_6.04O₂₇(OH)₄ is described from Engusero Sambu, northern Tanzania (On maps, Engusero Sambu may be found to be marked as belonging to Kenya, but in reality, it is located near the border in northern Tanzania). The sample has an unusual red color that is distinctly different from the red dravite from the Osarara, Narok district, in Kenya that was formerly studied by Mattson and Rossman (Phys Chem Miner 14:225–234, 1984) and Taran and Rossman (Am Mineral 87:1148–1153, 2002). This unique sample has been characterized by optical and Mössbauer spectral measurements to investigate underlying cause of the intense bands in absorption spectra that give rise to the red color. These features are shown to be caused by exchange-coupled Fe³⁺–Fe³⁺ interactions. Thermal annealing of the samples causes an increase in Fe³⁺ contents due to oxidation of ^[Y]Fe²⁺. However, heat treatment does not change the high-energy absorption edge, which is probably caused by intense ligand-to-Fe³⁺ charge-transfer UV bands. In fact, Mössbauer results show that high-temperature annealing initiates breakdown of the tourmaline into an Fe oxide and causes accompanying redistribution of Fe³⁺ within the structure. Because of the popularity of tourmaline as a gemstone, this work has implications for understanding the causes of color in tourmaline, facilitating recognition of the distinctions between naturally occurring and treated tourmalines in the gem industry and enabling heat treatments for color enhancement.     

红外光谱-显微共焦激光拉曼光谱研究天然红宝石和蓝宝石中含水矿物包裹体特征

天然红宝石和蓝宝石的包裹体中常见典型的含水矿物包裹体,这些含水矿物包裹体容易受外界环境升温而发生改变。微量含水矿物包裹体变化会对红宝石和蓝宝石的物理和化学性质产生明显影响,该性质为宝石热处理的鉴定提供了检测思路。本文采集了天然红宝石和蓝宝石样品,用显微镜放大观察包裹体特征,结合红外光谱与显微共焦激光拉曼光谱测试研究了含水矿物包裹体的特征。结果表明:天然红宝石和蓝宝石样品中含水矿物包裹体的外观轮廓清晰,晶形完整;红外光谱在2000～3700cm~(-1)附近显示出2105～2110cm~(-1)和1977～1985cm~(-1)硬水铝石和3619cm~(-1)和3696cm~(-1)高岭石等水(H_2O或—OH等)的特征吸收峰;拉曼光谱中可见角闪石、云母、磷灰石和长石等结晶度较好的典型含水矿物包裹体的特征拉曼位移。该系列特征揭示了红宝石和蓝宝石样品中含有水的特征,可作为红宝石和蓝宝石天然成因且未经过热处理的鉴定依据。     

Study of compact radio sources using interplanetary scintillations at 111 MHz. Strong gigahertz-peaked spectrum sources

Observations of a sample of gigahertz-peaked spectrum sources have been carried out using the interplanetary-scintillation method. Scintillations were recorded in six of 53 observed sources; upper estimates for the flux density of the compact emission were obtained for the remaining sources. The contribution of a halo to the integrated flux at low frequencies is considered. Three sources with spectral indices close to ?2.5 below the spectral cutoff have been found. The synchrotron self-absorption of emission in the studied sources is discussed.     

红外光谱-拉曼光谱无损检测技术对透闪石和阳起石鉴定特征的研究

透闪石属于角闪石族矿物,与阳起石构成完全类质同象,有关透闪石和阳起石的红外光谱和拉曼光谱的特征差异还未见有报道。本文以外观特征相似的5件广西大化黑青色阳起石样品和2件新疆塔县青玉样品为研究对象,在前期矿物成分测试的基础下,采用红外光谱和拉曼光谱进行测试和对比分析。结果表明,阳起石的红外光谱和拉曼光谱都表现为闪石类矿物的特征峰,与透闪石的特征峰存在细微差异,漫反射红外光谱的差异特征是鉴别两者最准确、快速、无损的依据,并且适用于任意形状的样品,符合珠宝玉石饰品实验室检测领域的要求,可为和田玉的分类分级和产地鉴别等提供科学依据。按照GB/T 16552-2017与GB/T 16553-2017规定,广西大化黑青色阳起石可定名为和田玉。     

Seismic response of a four-storey RC school building with masonry-infilled walls

This paper focuses on the evaluation of the effect of masonry-infilled walls on the seismic response of a four-storey RC school building. Numerical simulation is presented with respect to the building with and without masonry-infilled walls. The simulation employed force-based fibre elements for beams and columns, and a single equivalent diagonal strut to represent the masonry infill. The numerical model was verified through comparison with shake table test results. It was found that the presence of masonry-infilled walls has significant influence on the global response of the structure. Although the displacement of the structure with infilled wall is reduced in the in-plane direction, it was increased in both in-plane and out-of-plane directions when the infilled walls experienced loss in serviceability.     

Ground-Water pollution and its sources

Everybody wants clean water for drinking, bathing and other domestic uses, but not everybody appreciates the fact that our own actions are often the worst enemy in achieving that goal. Ground water is one of the most misused and misunderstood resources. Because ground water and its movement, and consequently also its pollution, is hidden from view beneath the land surface, the seriousness of ground-water pollution problems has not been recognized until recently. The sources of ground-water pollution are many and varied because in addition to natural processes practically every type of facility or structure installed by man and each and every one of his activities may eventually contribute to ground-water quality problems. The quality of ground water is most commonly affected by waste disposal. Other major sources result from agricultural activities and ground-water development. In addition to these three major categories, there are other potential sources of pollution, such as mining, spills, leakage from underground pipes and tanks, and road salting. All of these activities can generate pollutants which eventually may enter the ground-water systems and slowly begin to move through the subsurface environment. Once under the ground, the pollutants are hidden from view and the existence of ground-water pollution becomes evident only if they reemerge on the surface or in water wells. When this occurs, it is almost too late to do anything about it. The effects of pollution may remain in the aquifers for years, decades, or centuries, because the residence time (turnover) of ground water is very slow. Ground-water pollution may even result in aquifers or parts of quifers being damaged beyond repair.     

Energy sources for mantle plumes

Mantle plumes are the consequence of a focussed transfer of mass from mantle to core and are agents of outgassing from the mantle. The energy of propagation is derived from released energy of their formation, decreases in density, and partial fluidization. This energy is dissipated during distension and rupture of the overlying crust.

---

Zusammenfassung Mantelplumes haben ihren Ursprung in einer gezielten Massenverfrachtung vom Mantel zum Kern und führen zur Mantelentgasung. Die Fortpflanzungsenergie entsteht aus frei werdender Bildungsenergie, Dichteverminderung und teilweiser Verflüssigung. Die Energie verflüchtigt sich bei Ausdehnung und Rißbildung der überlagernden Kruste.

---

Résumé Plumes en le manteau sont derivées d'un transfert de masse dès le manteau au noyau. Elles sont agents de la dégassification du manteau. L'énergie de la propagation est derivée de l'énergie de la formation liberée, des décroissements de la densité, et de la fluidification partielle. Cette énergie est dissipée pendant la dilatation et la rupture de la croûte s'étendante là-dessus.

---

Plumes , . : , . .

     

Dipole sources of the main geomagnetic field

The parameters of 15 arbitrary dipoles that, in aggregate, represent the main geomagnetic field (MGF) are estimated to obtain information on the distribution of MGF sources within the Earth in the form of dipoles with an arbitrary position and value of the magnetic moment vector. For an adequate estimation of the results, the method of obtaining the data is described, including: the eccentric dipole model and the derivation of the basic formulas for the magnetic field components of an arbitrary dipole; the method of estimating the parameters of these dipoles, including the computational scheme and optimization method; necessary constraints on the dipoles parameters and a justification of the choice of the initial values in the optimization fitting of the parameters. The results are presented as a map of the location of the centers of the dipoles and their northern axial poles for the epochs 1955 and 2005 and plots of changes in all six parameters of 15 dipoles for 50 years. Most of the dipole centers are located in the lower mantle. The results suggest the existence of current systems in the lower mantle that produce dipole magnetic fields. These currents are provided by the high conductivity of wustite, an important component of the mantle, which, at a depth of 1000-2200 km, transforms to the low-spin state of iron with increased density and electrical conductivity.     

Intraday variability of three flat-spectrum radio sources

Searches for intraday variability in the flat-spectrum radio sources J0527+0331, J0721+0406, and J1728+0427 have been carried out at 3.5 cm using the 32-m radio telescope of the Zelenchuk Observatory of the Kvazar-KVO complex of the Institute of Applied Astronomy of the Russian Academy of Sciences (located near the Zelenchuk Village, Karachaevo-Cherkesskaya Republic). Intraday variabiility with characteristic time scales from one to five hours was detected in all three sources.     

Optical identifications and spectra of radio sources

We present classifications, optical identifications, and radio spectra for eight radio sources from three flux-density-complete samples in the following declination ranges: 4°–6° (B1950), S _3.9 > 200 mJy; 10°–12°30′ (J2000), S _4.85 > 200 mJy; 74°?75° (J2000), S _4.85 > 100 mJy. For all these samples, the right ascensions are 0^h–24^h and the Galactic latitudes, |b| > 15°. Our optical observations at 4000–7500 ° were made with the 6-m telescope of the Special Astrophysical Observatory; we also observed at 0.97–21.7 GHz with the RATAN-600 radio telescope of the Special Astrophysical Observatory. We classify four of the objects as quasars and four as galaxies. Five of the radio sources have power-law spectra at 0.97–21.7 GHz, while two objects have flat spectra. The quasar J2358+0430 virtually did not vary during 23 years.     

The evolutionary status of ultraluminous X-ray sources

We analyze models for quasi-stationary, ultraluminous X-ray sources (ULXs) with luminosities 10³⁸–10⁴⁰ erg/s exceeding the Eddington limit for a ～1.4M_⊙ neutron star. With the exception of relatively rare stationary ULXs that are associated with supernova remnants or background quasars, most ULXs are close binary systems containing a massive stellar black hole (BH) that accretes matter donated by a stellar companion. To explain the observed luminosities of ～10⁴⁰ erg/s, the mass of the BH must be ～40M_⊙ if the accreted matter is helium and ～60M_⊙ if the accreted matter has the solar chemical composition. We consider donors in the form of main-sequence stars, red giants, red supergiants, degenerate helium dwarfs, heavy disks that are the remnants of disrupted degenerate dwarfs, helium nondegenerate stars, and Wolf-Rayet stars. The most common ULXs in galaxies with active star formation are BHs with Roche-lobe-filling main-sequence companions with masses ～7M_⊙ or close Wolf-Rayet companions, which support the required mass-exchange rate via their strong stellar winds. The most probable candidate ULXs in old galaxies are BHs surrounded by massive disks and close binaries containing a BH and degenerate helium-dwarf, red-giant, or red-supergiant donor.