重庆城口地区早前寒武系黑色岩系研究:(1)铂族元素成矿潜力评估

重庆城口地区从震旦统到下寒武统发育有丰富的黑色岩系,20世纪末期在该地区黑色岩系中开展了大量的铂族元素(PGE)的找矿工作,但是由于种种原因,关于该地区是否存在PGE矿化异常,还没有得到最终的结论.本次研究在PGE分析方法论证的基础上,进行了大量样品的PGE分析和微量元素分析.主要结论如下①区域上上震旦统槽区和断块区两套黑色岩系在原始的沉积环境和物源供给上有较大的差异,虽然槽区上震旦统的黑色岩系具有和下寒武统黑色岩系相似但强度较低的V-Cu-Y-Mo-U异常,但基本上不具有明显的PGE-Au-Ag异常.②断块区水井沱组黑色岩系和平剖面西段新发现的U-V-Mo-PGE异常可能是今后工作的重点,Pt＋Pd最高达248.9×10-9,局部U-V都达到了工业品位.③槽区巴山组硅质岩四个剖面都揭示了在硅质岩中广泛存在连续的PGE异常,87个碳质硅质岩平均含Pt＋Pd 57.2×10-9,有10个样品Pt Pd》100×10-9,最高达196.5×10-9;大部分碳质硅质岩都具有不同程度的V-Cu-Y-Mo-Tl-U组合异常,V都达到了独立矿床的品位要求,其中猪草河、燕子河等剖面还存在厚度较大的富矿地段,特别是燕子河剖面,局部还存在REE＋Y的高异常,值得深入研究.④城巴地区下寒武统黑色岩系存在广泛的PGE异常,但没有达到PGE的矿化要求,建议加强该地区的钒矿和铀矿勘探研究,PGE可以综合评价.     

A two-zone model for the broad iron line emission in MCG–6-30-15

We reanalyse the ASCA and BeppoSAX data of MCG–6-30-15, using a double-zone model for the iron line profile. In this model, the X-ray source is located around ≈10 Schwarzschild radii and the regions interior and exterior to the X-ray source produce the line emission. We find that this model fits the data with a similar reduced χ ² to the standard single-zone model. Thus we show that the presence of a broad iron line feature does not necessarily require that the X-ray source be located close to the last stable orbit or in the disc rotation axis.
Within the framework of this model, the best-fitting inclination angle of the source     for the intermediate-intensity ASCA data set is compatible with that determined by earlier modelling of optical lines. The observed variability of the line profile with intensity can be explained as variations of the X-ray source size. That several active galactic nuclei with broad lines have the peak centroid near 6.4 keV can be explained under certain conditions.
We also show that the simultaneous broad-band observations of this source by BeppoSAX rule out the Comptonization model which was an alternative to the standard inner-disc one. We thereby strengthen the case that line broadening occurs as a result of the strong gravitational influence of a black hole.     

用硫酸镁和造纸草浆黑液制备吸附剂及其对活性黄ST-4RFN吸附研究

利用硫酸镁和造纸草浆黑液制备含镁氧化合物的吸附剂,通过化学分析、表面性质分析、X射线衍射和红外光谱等对吸附剂进行了表征.考察了吸附剂焙烧温度、投加量、吸附时间以及pH值等因素对活性黄ST-4RFN吸附性能的影响,吸附过程可用Freundlich模型来描述.     

季节冻土区黑土耕层土壤冻融过程及水分变化

利用黑龙江省水利科学研究院水利试验研究中心综合实验观测场2011年11月-2012年4月整个冻结融化期的实测野外黑土耕层土壤温度和水分数据, 对中-深季节冻土区黑土耕层土壤冻融过程中冻结和融化特征分阴、阳坡进行了分析, 研究了冻融过程中不同深度土壤水分的变化情况, 并探讨了降水对不同深度耕层土壤含水量变化的影响. 结果表明:黑土耕层土壤冻结融化过程分为5个阶段, 历时164 d, 约5.5个月. 阶段I, 秋末冬初黑土耕层土壤开始步入冻结期; 阶段II, 黑土耕层土壤整日处于冻结状态, 阴坡比同样深度的阳坡土壤温度低; 阶段III为黑土耕层土壤稳定冻结期; 阶段IV, 黑土耕层土壤步入昼融夜冻的日循环交替状态, 冻融循环的土层逐渐向深部发展, 阳坡比阴坡融化得更深、更早, 阴坡比阳坡经历冻融循环次数更多; 阶段V为稳定融化期, 在融化过程不存在冻融交替的现象, 直到整个冻层内的土壤全部消融. 各深度位置阴坡土壤温度的最高值出现时间比阳坡晚约0.5 h. 经过整个冻结融化期后, 阴、阳坡各层土壤含水量均大于冻结前, 阴坡土壤含水量比阳坡整体偏低. 在整个冻结融化期, 阳坡地下1 cm、5 cm、10 cm 及15 cm处含水量最大值出现在地下5 cm; 阴坡的含水量整体趋于平稳且在融化期受降水影响明显.     

高碳黑色页岩型铂族元素矿床性探讨

简析了高碳黑色页岩型铂族元素矿床（PGED）的研究现状，并根据矿床的特征初步将该类矿床划分为中层状黑色页岩，薄层状黑色页岩和高碳构造岩型3类；并从形成环境，成因等方面对PGED形成进行了剖析，强调了源区供给，有机迁移和热液叠加作用的差异是导臻形成不同类型黑色含碳页岩型铂族元素矿床的根源，指出了我国贵州－湖南高碳黑色页岩型铂族元素成矿性较差与层薄和叠加温度低有关。     

A simple mass estimate for central black holes in cuspy galaxies

We argue that the temperature of the stellar phase is likely a monotically decreasing function of radius in the central regions of elliptical galaxies with cusps. We show that it requires the presence of a central mass concentration. An estimate of its minimum mass based on few parameters is given. This lower bound is consistent with current mass values of the central objects in galaxies derived from detailed models. This revised version was published online in July 2006 with corrections to the Cover Date.     

Are Q-stars a serious threat for stellar-mass black hole candidates?

We examine the status of the threat posed to stellar-mass black hole candidates by the possible existence of Q-stars (compact objects with an exotic equation of state that might have masses well above the normally accepted maximum for standard neutron stars). We point out that Q-stars could be extremely compact (with radii less than 1.5 times the corresponding Schwarzschild radius) making it difficult to determine observationally that a given object is a black hole rather than a Q-star, unless there is direct evidence for the absence of a material surface. On the other hand, in order for a Q-star to have a mass as high as that inferred for the widely favoured black hole candidate V404 Cygni, it would be necessary for the Q-matter equation of state to apply already at densities an order of magnitude below that of nuclear matter and this might well be considered implausible on physical grounds. We also describe how rotation affects the situation and discuss the prospects for determining observationally that black hole candidates are not Q-stars.     

Non-axisymmetric relativistic Bondi–Hoyle accretion on to a Schwarzschild black hole

We present the results of an exhaustive numerical study of fully relativistic non-axisymmetric Bondi–Hoyle accretion on to a moving Schwarzschild black hole. We have solved the equations of general relativistic hydrodynamics with a high-resolution shock-capturing numerical scheme based on a linearized Riemann solver. The numerical code was previously used to study axisymmetric flow configurations past a Schwarzschild black hole. We have analysed and discussed the flow morphology for a sample of asymptotically high Mach number models. The results of this work reveal that initially asymptotic uniform flows always accrete on to the hole in a stationary way, which closely resembles the previous axisymmetric patterns. This is in contrast with some Newtonian numerical studies where violent flip-flop instabilities were found. As discussed in the text, the reason can be found in the initial conditions used in the relativistic regime, as they cannot exactly duplicate the previous Newtonian setups where the instability appeared. The dependence of the final solution on the inner boundary condition as well as on the grid resolution has also been studied. Finally, we have computed the accretion rates of mass and linear and angular momentum.     

Resonant tidal disruption in galactic nuclei

It has recently been shown by Rauch 38 Tremaine that the rate of angular momentum relaxation in nearly Keplerian star clusters is greatly increased by a process termed 'resonant relaxation'; it was also argued, via a series of scaling arguments, that tidal disruption of stars in galactic nuclei containing massive black holes could be noticeably enhanced by this process. We describe here the results of numerical simulations of resonant tidal disruption which quantitatively test the predictions made by Rauch 38 Tremaine. The simulation method is based on an N -body routine incorporating cloning of stars near the loss cone and a semirelativistic symplectic integration scheme. Normalized disruption rates for resonant and non-resonant nuclei are derived at orbital energies both above and below the critical energy, and the corresponding angular momentum distribution functions are found. The black hole mass above which resonant tidal disruption is quenched by relativistic precession is determined. We also briefly describe the discovery of chaos in the Wisdom–Holman symplectic integrator applied to highly eccentric orbits and propose a modified integration scheme that remains robust under these conditions. We find that resonant disruption rates exceed their non-resonant counterparts by an amount consistent with the predictions; in particular, we estimate the net tidal disruption rate for a fully resonant cluster to be about twice that of its non-resonant counterpart. No significant enhancement in rates is observed outside the critical radius. Relativistic quenching of the effect is found to occur for hole masses M  >  M _Q  = (8 ± 3) × 10⁷  M . The numerical results combined with the observed properties of galactic nuclei indicate that for most galaxies the resonant enhancement to tidal disruption rates will be very small.