Titanium Isotope Analysis of Igneous Reference Materials using a Double-spike MC-ICP-MS Method

Ti separation was achieved by ion-exchange chromatography using Bio-Rad AG 1-X8 anion-exchange and DGA resins. For high-Fe/Ti and high-Mg/Ti igneous samples, a three-column procedure was required, whereas a two-column procedure was used for low-Fe/Ti and low-Mg/Ti igneous samples. The Ti isotopes were analysed by MC-ICP-MS, and instrumental mass bias was corrected using a 47Ti-49Ti double-spike technique. The 47Ti-49Ti double-spike and SRM 3162a were calibrated using SRM 979-Cr, certificated value 53Cr/52Crtrue = 0.11339. Isobaric interference was evaluated by analysing Alfa-Ti doped with Na, Mg, Ca, and Mo, and results indicate that high concentrations of Na and Mg have no significant effect on Ti isotope analyses; however, Ca and Mo interferences lead to erroneous δ49/47Ti values when Ca/Ti and Mo/Ti ratios exceed 0.01 and 0.1, respectively. Titanium isotopic compositions were determined for 12 igneous reference materials, BCR-2, BHVO-2, GBW07105, AGV-1, AGV-2, W-2, GBW07123, GBW07126, GBW07127, GBW07101, JP-1, and DTS-2b. Samples yield δ49/47Ti (‰) of ?0.035 ± 0.022, ?0.038 ± 0.031, 0.031 ± 0.022, 0.059 ± 0.038, 0.044 ± 0.037, 0.000 ± 0.015, 0.154 ± 0.044, ?0.044 ± 0.018, 0.010 ± 0.022, 0.064 ± 0.043, 0.169 ± 0.034, and ?0.047 ± 0.025 (relative to OL-Ti, ±2SD), respectively; of which isotopic compositions of DTS-2b, JP-1, GBW07101, GBW07105, GBW07123, GBW07126, and GBW07127 are reported for the first time. Standard Alfa-Ti was analysed repeatedly over a ten-month period, indicating a reproducibility of ±0.047 (2SD) for δ49/47Ti, similar to the precisions obtained for geochemical reference materials.     

强震作用下冰水域桥墩动力响应研究分析

地震作用下冰水域桥墩受到动水压力与动冰荷载的的双重影响。基于Morison动水理论和Croteau动冰力模型,提出一种适用于冰水域桥墩动力时程反应分析的简便计算模型,通过振动台试验验证了其有效性,并分析了海冰质量和水深对冰海域桥墩动力响应的影响。结果表明,强震作用下有冰时墩底最大曲率比无冰时最大增加8.93倍,桥墩被自由冰包围时,墩底截面出现最大曲率时对应的海冰质量随着水深的增加而变大;随着冰质量的持续增大,墩身最大位移易超越极限位移,造成桥梁垮塌,在桥梁设计中应重点考虑。     

水中氯代烃单体碳同位素分析中预富集方法进展

高精度准确测定氯代烃单体碳同位素对示踪污染物来源,了解污染物的生物降解过程具有重要意义。在环境转化过程中,有机污染物的同位素组成可能是稳定不变的,也有可能发生改变。若污染物的同位素组成在迁移转化过程中不变,根据其同位素组成可以示踪污染物的来源;若同位素组成变化,根据同位素分馏结果,可以评价环境中有机污染物降解发生的可能性和程度。本文综述了固相微萃取、静态顶空进样、吹扫-捕集、多级串联技术等前处理方法与气相色谱-燃烧-同位素比值质谱仪(GC-C-IRMS)联用分析水中氯代烃单体碳同位素的研究进展,比较了分析方法的优缺点。液-液萃取较少用于水中氯代烃的单体同位素分析。静态顶空进样、固相微萃取、吹扫-捕集都是无溶剂富集技术,与GC-C-IRMS联用分析水中氯代烃单体同位素过程中不存在或存在小且恒定的可校正的同位素分馏,分析精度一般优于1‰,没有二次污染,降低了杂质干扰,提高了GC-C-IRMS的分辨率和分析精度,降低了检测限。从静态顶空进样、固相微萃取、吹扫-捕集,到多级串联等技术与GC-C-IRMS联用分析水中氯代烃单体同位素比值,检测限逐渐降低。目前,吹扫-捕集-GC-C-IRMS在分析水中氯代烃中应用最广泛,重现性好、检测限低。针内微萃取、管内微萃取、搅动棒吸附萃取和顶空进样吸附萃取等前处理方法与GC-C-IRMS仪联用具有一定的应用前景。     

岩体结构统计均质区的划分

本文介绍由Ｍｉｌｌｅｒ提出的基本概率统计理论的关联表分析，结合施密特投影图研究岩体统计均质区的划分方法。对该法进行了适当的修改，编写了相应的计算机程序。并对三峡永久船闸地区的岩体结构，进行了岩体结构统计均质区的划分，获得了良好的效果。     

西藏申扎县索尔碎屑岩岩石学特征及其成因

索尔碎屑岩出露于西藏中部索尔—戈昂错一带,角度不整合覆盖于果芒错蛇绿混杂岩中的地幔橄榄岩之上,粗碎屑岩层和细碎屑岩层互层产出,并见有角砾状灰岩夹层。索尔碎屑岩中粗碎屑岩主要由灰黑色碎屑和土黄色基质所组成;细碎屑岩呈灰黑色,块状构造。碎屑的主体成分为蛇纹岩,并含有少量的尖晶石和斜长石,基质为泥晶结构碳酸盐。碎屑主要呈棱角状—次圆状,边界平直,可能是构造破碎后快速堆积而形成的。在蛇纹岩碎屑边部普遍可见垂直边界生长的板状或粒状方解石,部分碎屑之中方解石呈逐步向内部生长的趋势,而在少量的岩石中已形成了交代残余结构,反映索尔碎屑岩中的碎屑受到了碳酸盐不同程度的交代作用。通过与Gebel Mohagara蛇绿质碳酸盐岩和West Magnitogorsk古岛弧中出露的蛇绿质碳酸盐岩对比研究,初步认为索尔碎屑岩是地幔橄榄岩发生破碎后受到碳酸盐热液流体的交代所形成的。     

Vertical structures of PM10 and PM 2.5 and their dynamical character in low atmosphere in Beijing urban areas

The vertical structures and their dynamical character of PM2.5 and PM10 over Beijing urban areas are revealed using the 1 min mean continuous mass concentration data of PM2.5 and PM10 at 8, 100, and 320 m heights of the meteorological observation tower of 325 m at Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP CAS tower hereafter) on 10―26 August, 2003, as well as the daily mean mass concentration data of PM2.5 and PM10 and the continuous data of CO and NO2 at 8, 100 (low layer), 200 (middle layer), and 320 m (high layer) heights, in combination with the same period meteorological field observation data of the meteorological tower. The vertical distributions of aerosols observed on IAP CAS tower in Beijing can be roughly divided into two patterns: gradually and rapidly decreasing patterns, I.e. The vertical distribution of aerosols in calm weather or on pollution day belongs to the gradually decreasing pattern, while one on clean day or weak cold air day belongs to the rapidly decreasing pattern. The vertical distributive characters of aerosols were closely related with the dynamical/thermal structure and turbulence character of the atmosphere boundary layer. On the clean day, the low layer PM2.5 and PM10 concentrations were close to those at 8 m height, while the concentrations rapidly decreased at the high layer, and their values were only one half of those at 8 m, especially, the concentration of PM2.5 dropped even more. On the clean day, there existed stronger turbulence below 150 m, aerosols were well mixed, but blocked by the more stronger inversion layer aloft, and meanwhile, at various heights, especially in the high layer, the horizontal wind speed was larger, resulting in the rapid decrease of aerosol concentration, I.e. Resulting in the obvious vertical difference of aerosol concentrations between the low and high layers. On the pollution day, the concentrations of PM2.5 and PM10 at the low, middle, and high layers dropped successively by, on average, about 10% for each layer in comparison with those at 8 m height. On pollution days, in company with the low wind speed, there existed two shallow inversion layers in the boundary layer, but aerosols might be, to some extent, mixed below the inversion layer, therefore, on the pollution day the concentrations of PM2.5 and PM10 dropped with height slowly; and the observational results also show that the concentrations at 320 m height were obviously high under SW and SE winds, but at other heights, the concentrations were not correlated with wind directions. The computational results of footprint analysis suggest that this was due to the fact that the 320 m height was impacted by the pollutants transfer of southerly flow from the southern peripheral heavier polluted areas, such as Baoding, and Shijiazhuang of Hebei Province, Tianjin, and Shandong Province, etc., while the low layer was only affected by Beijing's local pollution source. The computational results of power spectra and periods preliminarily reveal that under the condition of calm weather, the periods of PM10 concentration at various heights of the tower were on the order of minutes, while in cases of larger wind speed, the concentrations of PM2.5 and PM10 at 320 m height not only had the short periods of minute-order, but also the longer periods of hour order. Consistent with the conclusion previously drawn by Ding et al., that air pollutants at different heights and at different sites in Beijing had the character of "in-phase" variation, was also observed for the diurnal variation and mean diurnal variation of PM2.5 and PM10 at various heights of the tower in this experiment, again confirming the "in-phase" temporal/spatial distributive character of air pollutants in the urban canopy of Beijing. The gentle double-peak character of the mean diurnal variation of PM2.5 and PM10 was closely related with the evident/similar diurnal variation of turbulent momentum fluxes, sensible heat fluxes, and turbulent kinetic energy at various heights in the urban canopy. Besides, under the condition of calm weather, the concentration of PM2.5 and PM10 declined with height slowly, it was 90% of 8 m concentration at the low layer, a little lesser than 90% at the middle layer, and 80% at the high layer, respectively. Under the condition of weak cold air weather, the concentration remarkably dropped with height, it was 70% of 8 m concentration at the low layer, and 20%―30% at the middle and high layers, especially the concentration of PM2.5 was even lower.     

混合沉积和混积岩的讨论

混合沉积物是指陆源碎屑与碳酸盐(包括异化粒等)在沉积上的混合。混合沉积可分为狭义的和广义的,狭义的是指陆源碎屑与碳酸盐组份的混合(在同一岩层内),而广义的混合则包括了狭义的和陆源碎屑与碳酸盐层构成交替互层或夹层的混合。混合沉积很早就引起了人们的注意,尽管碎屑岩和碳酸盐岩的研究与应用已很成熟,但对混积岩的研究多被忽视了。对狭义的混合沉积物有必要起一成因名称——混积岩。当人们接触到混合沉积时,除了分析研究它们的组分和结构特征外,还必须去思考,它们为什么能经常频繁地交互出观,或是直接混合在一起?倒底是：①陆源碎屑跑到碳酸盐的沉积背景里?②碳酸盐跑到陆源碎屑的沉积背景里?③二分别从各自的源地跑到第三种沉积背景里?还是④二本来就在同一沉积背景里?接下来就要思考是什么动力条件使它(们)能从这个沉积背景(环境)“跑”到另一个沉积背景(环境)里去?是水?是风?是自身?还是别的什么力量?那么,又是怎样的水动力或风动力条件呢?是正常条件,还是突发事件?很明显,要分析研究混合沉积和混积岩。这些问题就不得不细细加以考虑,深入进行研究。     

湖南香花岭复式碱长花岗岩体侵入期次关系的识别

香花岭碱长花岗岩为一复式岩体。不同期次侵入体之间的接触关系、白色和绿色含铍条纹岩以及磁铁矿条纹岩与不同期次侵入体之间的对应关系、通天庙、塘官铺、太平和新风不同矿化组合与不同期次侵入体之间的成因联系以及遥感图像中的环形构造特点和差异明显的Rb-Sr同位素等时年龄表明该岩体是两期四次碱长花岗质岩浆侵入作用的产物,燕山早期的三次岩浆侵入与本区矿化关系密切;而燕山晚期的一次岩浆侵入与矿化无关。上述认识可对矿区的某些地质问题作出合理的解释。     

气团分类及其与贵州气候灾害的关系

通过对贵州3站点历年逐日地面气象要素进行统计分类，分析影响贵州的气团活动规律，并对贵州气候灾害与各类气团活动频数作相关分析。结果表明：贵州气候受多种气团活动的影响，各型气团对应特定的天气特征及一定的环流背景。另外，气候灾害与某些气团活动变化具有很好的相关性，这对进一步研究贵州气候变化及气候灾害成因具有一定的现实意义。     

PLS法与隧道围岩稳定性分类

围岩稳定性是隧道工程支护设计的基本参数,采用偏最小二乘回归法,综合考虑多因变量影响因素,对隧道围岩稳定性分类进行回归建模,并取得较好效果.