The anomalous properties of Markarian 1460

We present and discuss optical, near-infrared and H  i measurements of the galaxy Markarian 1460 at a distance of 19 Mpc in the Ursa Major Cluster. This low-luminosity ( M _B =−14) galaxy is unusual because (i) it is blue ( B − R =0.8) and has the spectrum of an H  ii galaxy, (ii) it has a light profile that is smooth and well fitted by an r ^1/4 and not an exponential function at all radii larger than the seeing, and (iii) it has an observed central brightness of about μ _B =20 mag arcsec⁻² , intermediate between those of elliptical galaxies (on the bright μ _B side) and normal low-luminosity dwarf irregular (on the low μ _B side) galaxies. No other known galaxy exhibits all these properties in conjunction. On morphological grounds this galaxy looks like a normal distant luminous elliptical galaxy, since the Fundamental Plane tells us that higher luminosity normal elliptical galaxies tend to have lower surface-brightnesses. Markarian 1460 has 2×10⁷ M_⊙ of H  i and a ratio M (H  i )/ L _B of 0.2, which is low compared to the typical values for star-forming dwarf galaxies. From the high surface-brightness and r ^1/4 profile, we infer that the baryonic component of Markarian 1460 has become self-gravitating through dissipative processes. From the colours, radio continuum, H  i and optical emission line properties, and yet smooth texture, we infer that Markarian 1460 has had significant star formation as recently as ∼1 Gyr ago but not today.     

GMRT detection of HI 21 cm-line absorption from the peculiar galaxy in Abell 2125

Using the recently completed Giant Meterwave Radio Telescope, we have detected the HI 21 cm-line absorption from the peculiar galaxy C153 in the galaxy cluster Abell 2125. The HI absorption is at a redshift of 0.2533, with a peak optical depth of 0.36. The full width at half minimum of the absorption line is 100 km s⁻¹. The estimated column density of atomic Hydrogen is 0.7×10²²(T _s /100) cm⁻². The HI absorption is redshifted by ∼400km s⁻¹ compared to the [OIII] emission line from this system. We attribute this to an infalling cold gas or to an out-flowing ionised gas, or to a combination of both as a consequence of tidal interactions of C153 with either a cluster galaxy or the cluster potential.     

铅电解原料工业硅氟酸中硫酸根的快速测定

用硝酸钾溶液沉淀硅氟酸根离子，分离大量的基体，滤液与氯化钡在保护剂的作用下，形成硫酸钡悬浊液，用分光光度计于波长440nm处测定其吸光度。方法的表观摩尔吸光系数为1.7×10^5L·mol^-1·cm^-1，测定范围为0、04～0．48g／L。应用于铅电解原料工业硅氟酸中硫酸根的测定，结果与重量法基本一致，7次测定的相对标准偏差小于7％，加标回收率为97．5％～101．7％。     

甘肃省产业转型及其生态环境效应研究

产业转型在促进区域社会经济繁荣的同时,也对生态环境产生重要影响.分析了甘肃省产业发展轨迹以及不同产业发展对生态环境的影响,利用不同产业的生态环境影响指数计算了1980年以来该省产业转型的生态环境效应.得出以下结论:1980年以来,甘肃省产业结构发生了较大变动,经历了2次产业转型;产业结构生态环境影响属于中等,1980年以来出现2次大的波动,存在降低后又反弹现象;产业转型轨迹与产业转型引起的生态环境效应轨迹在变化趋势上存在着一致性,都呈明显的 "波浪形";产业转型对生态环境的影响滞后于产业转型;基于生态环境保护的产业转型任务相当艰巨,亟需实施基于生态环境保护的长效产业政策.     

福建省产业结构地区差异聚类分析

选取1995-2004年数据，对福建省各地区经济增长情况进行偏离-份额分析，以此为依据对福建省9个地级市进行聚类分析，将其产业结构的特点分成产业结构贡献率与竞争力贡献率都大于零、产业结构贡献率小于零而竞争力贡献率大于零、产业结构贡献率和竞争力贡献率都小于零三类，说明福建省产业结构地区差异明显，并对不同地区产业结构对经济增长的贡献情况进行分析，以期为福建省各地区产业结构调整和优化提供一定的参考价值。     

Chandra X-ray observations of the 3C 295 cluster core

We examine the properties of the X-ray gas in the central regions of the distant ( z =0.46) , X-ray luminous cluster of galaxies surrounding the powerful radio source 3C 295, using observations made with the Chandra Observatory . Between radii of 50 and 500 kpc, the cluster gas is approximately isothermal with an emission-weighted temperature, kT ∼5 keV . Within the central 50-kpc radius this value drops to kT ∼3.7 keV . The spectral and imaging Chandra data indicate the presence of a cooling flow within the central 50-kpc radius of the cluster, with a mass deposition rate of approximately 280 M_⊙ yr⁻¹. We estimate an age for the cooling flow of 1–2 Gyr , which is approximately 1000 times older than the central radio source. We find no evidence in the X-ray spectra or images for significant heating of the X-ray gas by the radio source. We report the detection of an edge-like absorption feature in the spectrum for the central 50-kpc region, which may be caused by oxygen-enriched dust grains. The implied mass in metals seen in absorption could have been accumulated by the cooling flow over its lifetime. Combining the results on the X-ray gas density profile with radio measurements of the Faraday rotation measure in 3C 295, we estimate the magnetic field strength in the region of the cluster core to be B ∼12 μG .     

Direct N-body modelling of stellar populations: blue stragglers in M67

We present a state-of-the-art N -body code which includes a detailed treatment of stellar and binary evolution as well as the cluster dynamics. This code is ideal for investigating all aspects relating to the evolution of star clusters and their stellar populations. It is applicable to open and globular clusters of any age. We use the N -body code to model the blue straggler population of the old open cluster M67. Preliminary calculations with our binary population synthesis code show that binary evolution alone cannot explain the observed numbers or properties of the blue stragglers. On the other hand, our N -body model of M67 generates the required number of blue stragglers and provides formation paths for all the various types found in M67. This demonstrates the effectiveness of the cluster environment in modifying the nature of the stars it contains, and highlights the importance of combining dynamics with stellar evolution. We also perform a series of N =10 000 simulations in order to quantify the rate of escape of stars from a cluster subject to the Galactic tidal field.