Fluorescent Lyman α emission from gas near a QSO at redshift 4.28

We use integral field spectroscopy with the Gemini North Telescope to detect probable fluorescent Lyman α (Lyα) emission from gas lying close to the luminous QSO PSS 2155+1358 at redshift 4.28. The emission is most likely coming not from primordial gas, but from a multiphase, chemically enriched cloud of gas lying about 50 kpc from the QSO. It appears to be associated with a highly ionized associated absorber seen in the QSO spectrum. With the exception of this gas cloud, the environment of the QSO is remarkably free of neutral hydrogen. We also marginally detect Lyα emission from a foreground subdamped Lyα absorption-line system.     

原子吸收分光光度法测定肉类样品中微量的铜铅锌镉

采用原子吸收法对肉类样品微量铜铅锌镉进行测定，重点对样品的前处理进行实验，拟订测试操作规程和仪器测量最佳条件，实验证明本法操作简便，准确快速，结果满意。     

制作包括吸收和波散效应的VSP合成记录

在地球物理勘探中,岩性勘探已成为很受重视的研究课题。Q值测井是确定地下岩性的一种方法,而制做包括吸收和波散效应的VSP合成记录是利用VSP资料做Q值测井的一个重要方面。本文详细地介绍了包括吸收和波散效应的VSP合成记录的具体制作过程,附有程序框图。本文还对震源不在地表时如何修正进行了分析,在此基础上把震源在地表和震源在任意深度两种情况统一起来,用同一公式表达。     

Determining Rayleigh damping parameters of soils for finite element analysis

Soil damping ratio is an important parameter for modelling the dynamic behaviour of soil embankment structures, especially for the micro‐vibration analysis of hospitals and high‐tech industries, which have a very severe construction requirement for vibration. This paper explores using a least‐squares method to evaluate the Rayleigh damping parameters for the finite element analysis of wave propagation in soils. The least‐squares method was first used in Bornitz's equation to calculate the absorption coefficients of soils. Afterward, the best‐fit Rayleigh damping parameters were obtained using those coefficients in the least‐squares scheme again. Both three‐dimensional finite element analyses and field experiments were performed to validate the accuracy of this method. The comparison between experimental and finite element results demonstrates that the accuracy of this least‐squares method is acceptable. Copyright © 2007 John Wiley & Sons, Ltd.     

粘弹性介质单程波法非零偏移距地震数值模拟与偏移

地震资料分辨率降低,得不到深层介质的精确信息实际上是由于大地吸收效应的影响.同时与双程波动方程相比单程波动方程避免了多次波的干扰并且计算效率高、占用内存少.本文首先基于开尔芬粘弹性介质模型将品质因子与单程波分步傅立叶法波场延拓算子相结合,实现了粘弹性介质波场延拓,从而将单程波弹性介质波场延拓推广到了粘弹性介质.然后在定位原理,数学检波器原理以及等时叠加原理的基础之上实现了粘弹性介质非零偏移距叠前正演模拟.最后将数值模拟得到的正演记录进行弹性偏移和粘弹性偏移并进行对比分析.通过数值算例可以看出,粘弹性介质叠前正演深层的反射波能量减弱,同相轴变粗,频带变窄,主频减小,分辨率降低;粘弹性偏移不但实现了振幅的恢复,而且同时偏移剖面的垂向空间分辨率也得到了提高.