Medium-size polarized basis sets for high-level-correlated calculations of molecular electric properties

Summary The first-order polarized basis sets for the use in high-level-correlated investigations of molecular electric properties have been generated for Pb, Bi, Po, and At. The performance of the standard [10.17.14.5/13.11.8.2] and extended [20.17.14.9/13.11.8.4] basis sets has been examined in nonrelativistic and quasirelativistic calculations for atoms and simple closed-shell hydrides. The relativistic contributions to electric dipole properties of those systems have been evaluated by using the recently developed quasirelativistic scheme. The predicted dipole polarizability of At is in good agreement with the results of other relativistic calculations. The calculated quasirelativistic dipole moments of BiH₃ (–0.499 a.u.), PoH₂ (–0.207 a.u.), and AtH (+0.036 a.u.) involve a significant relativistic contribution which amounts to —0.230 a.u., –0.177 a.u., and –0.097 a.u., respectively. The basis set details append this paper. They are also available as a part of the basis set library of the MOLCAS system.     

14C dating of ancient rock art: A new application of plasma chemistry

We have developed a new statically operated oxygen plasma method that allows direct¹⁴C dates to be obtained from ancient rock paintings. The method is applicable even to paintings on limestone (CaCO₃) walls. A sample of a pictograph which had naturally spalled offa shelter wall in the Lower Pecos region of Texas was subjected to a low temperature ( 150°C) oxygen plasma to selectively remove the organic carbon-containing material used in the paint as CO₂, without contamination from the limestone substrate. The Zürich EHT accelerator mass spectrometer was then used to determine the radiocarbon age of this prehistoric rock painting. It was successfully dated at 3865 ± 100 years BP, in good accord with the archaeological context which has set the onset of this Pecos River style of pictograph between 4100 and 3200 years BP. The method appears feasible and is applicable to rock art in which organic materials were used in the paint.     

Thermal Decomposition of Bi(III), Cd(II), Pb(II) and Cu(II) Thiocyanates

Thermal decomposition of Bi(SCN)₃, Cd(SCN)₂, Pb(SCN)₂ and Cu(SCN)₂ has been studied. The thermal analysis curves and the diffraction patterns of the solid intermediate and final products of the pyrolysis are presented. The gaseous products of the decomposition (SO₂ and CO₂) were detected and quantitatively determined. Thermal, X-ray and chemical analyses have been used to establish the nature of the reactions occurring at each stage in the decomposition.This revised version was published online in November 2005 with corrections to the Cover Date.     

Adsorption Characteristics of Pb(II) and Cr(III) onto C‐4‐Methoxyphenylcalix[4]Resorcinarene in Batch and Fixed Bed Column Systems

A study on the adsorption characteristics of Pb(II) and Cr(III) cations onto C‐4‐methoxyphenylcalix‐[4]resorcinarene (CMPCR) in batch and fixed bed column systems has been conducted. CMPCR was produced by one step synthesis from resorcinol, 4‐methoxybenzaldehyde, and HCl. The synthesis was carried out at 78 °C for 24 hours and afforded the adsorbent in 85.7% as a 3:2 mixture of C_4ν:C_2ν isomer. Most parameters in batch and fixed bed column systems confirm that CMPCR is a good adsorbent for Pb(II) and Cr(III), though Pb(II) adsorption was more favorable than that of Cr(III). The adsorption kinetic of Pb(II) and Cr(III) adsorptions in batch and fixed bed column systems followed a pseudo 2ⁿ order kinetics model. The rate constant of Pb(II) was higher than that of Cr(III) in the batch system, but this result was contrary to the result obtained in a fixed bed column system. Desorption studies to recover the adsorbed Pb(II) and Cr(III) were performed sequentially with distilled water and HCl, and the results showed that the adsorption was dominated by chemisorption.     

释光测年在应用研究方面的新进展

根据释光测年是地质学研究和考古学研究领域重要的研究手段和断代方法，总结出了在近十多年来应用该方法在以下几个方面所取得的成果及进展：（1）主要包括激发光源、晒退光源、辐射源以及操作软件等技术设备方面的巨大进展，以及由于释光测年技术设备精度的提高而由此极大地降低了释光测年的系统误差；（2）以单片再生测年技术和线性调整技术为代表的多种测年方法的快速发展，使得不同类型样品等效剂量的测定更加准确，而且测年流程更加简单易于操作；（3）测年材料不仅包括经受热过（主要是陶瓦）和经充足曝光的物质，同时对未经充足曝光的物质（如水积物和崩积物等）和其他经受热过的物质（如断层泥等）等也进行了大量的测年研究，从而极大地拓展了释光测年的应用领域；（4）各种年剂量测定方法的相互补充降低了在年剂量测定方面的不确定性．     

Pb isotopic geochemical study on the crustal structure of Tongbaishan

Pb isotopic composition of the Tongbai complex, distributed in the Tongbaishan to the west of the Dabieshan, ranges between the Dabie core complex and the Dabie ultral-high pressure (UHP) metamorphic complex, the latter having more radiogenic Pb isotopic composition than the former. Granites from the Jigongshan pluton, which intruded mainly into the Tongbai complex, are distinct from the Tongbai complex but similar to the Dabie core complex in Pb isotopic composition, showing that the magma of the Jigongshan granites was derived from the partial melting of the Dabie core complex. According to Pb isotopic compositional variation model in the vertical crustal section and magma source from the Jigongshan pluton, it is suggested that the Tongbai complex was an upper rock serial of the Dabie core complex, which is beneath the Dabie UHP metamorphic complex in the crustal structure of the Tongbai-Dabie orogenic belt. The Tongbai complex was not well preserved in the Dabie area due to the high exhumed crustal section. However, the crustal section in the Tongbai area was exhumed less than that in the Dabie area, and the deep crust in the Tongbai area still contains the basement composition similar to the Dabie core complex. Therefore, the crustal basements from the Dabie to Tongbai areas are united. The present distribution of the basement blocks in different locations of the Tongbai-Dabie orogenic belt reflects different exposure of the crustal section.     

浙江天台大岭口银(金)铅锌矿床的成矿物质来源

浙江天台大岭口银（金）铅锌矿床是产于浙东中生代陆相火山岩中最具代表性的热液脉状矿床。文章根据区域矿床地质特征和成矿的物理化学条件，运用矿床稳定同位素和主要指示元素的地球化学，论证了成矿热液中介质水和金属元素的来源。     

汉诺坝非橄榄岩类包体的化学和同位素特征

汉诺坝非橄榄岩包体主要是指辉石岩、辉长岩和麻粒岩，其主要元素、微量元素有较大和系统的变化，Ｎｄ、Ｓｒ、Ｐｂ同位素从非常亏损的ＤＭＭ源特征变至具ＥＭＩ和ＥＭＩ源趋势的富化特征．它们与寄主玄武岩及共生的橄榄岩包体无直接成因联系，有不同的形成时代并在不同的空间位置居留     

Determination on ^87Sr/^86Sr ratio and stratigraphic dating of single-grain foraminifera

Information on palaeoocean and palaeoclimate can be recorded in foraminifera, and formation ages of the fo- raminifera are nevertheless essential for such study of pa- laeoenvironment. The growth rate of seamount ferroman- ganese crusts is normally very l…     

SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications

The Jinniu Basin in southeast Hubei,located at the westernmost part of middle-lower val-ley of the Yangtze River,is one of the important vol-canic basins in East China. Volcanic rocks in the Jin-niu Basin are distributed mainly in the Majiashan Formation,the Lingxiang Formation and the Dasi Formation,consisting of rhyolite,basalt and basaltic andesite,(trachy)-basalt and basaltic trachy-andesite and (trachy)-andesite and (trachy)-dacite and rhyolite respectively,in which the Dasi volcanism is volumet-rically dominant and widespread. The Dasi volcanic rocks were selected for SHRIMP zircon U-Pb dating to confirm the timing of volcanism. The results indi-cate that there exist a large amount of magmatic zir-cons characterized by high U and Th contents in the volcanic rocks. The concordia ages for 13 points are 128 ± 1Ma (MSWD = 3.0). On account of the shape of zircons and Th/U ratios,this age is considered to represent the crystallization time of the Dasi volcan-ism. The volcanic rocks in the Dasi,Majiashan and Lingxiang Formations share similar trace elementand REE partition patterns as well as Sr-Nd isotopic compositions. In combination with the regional geol-ogy,it is proposed that the southeast Hubei volcanic rocks were formed mainly during the Early Creta-ceous,just like other volcanic basins in middle-lower Yangtze valley. A lithospheric extension is also sug-gested for tectonic regime in this region in the Cre-taceous Period.