Calculation of the structure and transition probabilities of low energy levels of Fe and Fe

We use analytical wave functions in intermediate coupling to make a complete relativistic calculation of the structure and transition probabilities for the n = 1, 2, 3 states of Fe⁺²⁴. Data for Fe⁺²⁵ are also given for comparison. The results have a high accuracy and those relating to the n = 3 state are given in detail for the first time here.     

星载铷原子频率标准的可靠性研究

星载原子频率标准在许多空间系统中担当着重要的角色,其性能和可靠性对这些系统的功能有重要的影响。介绍了广泛使用的星载铷原子频率标准的基本工作原理,分析了影响其可靠性的各种因素,并探讨了提高其可靠性的基本途径。     

山东半岛近岸海带养殖活动对水体光学吸收特性的影响

为了研究近岸海带养殖活动对水体光学特性的影响,本文选取山东半岛黑泥湾海域为典型研究区,利用2021年4月和8月在该区的9站同步观测数据,分析其总悬浮颗粒物、藻类颗粒物、非藻类颗粒物以及有色溶解有机物的吸收特性,并计算各组分对总吸收系数的贡献率,同时采用Quasi-analytical algorithm (QAA)算法借助MODIS影像反演了水体总吸收系数,结合实测数据获得了黑泥湾水体吸收特性的季节变化情况。结果表明,有海带养殖季节表层水体藻类颗粒物、非藻类颗粒物、总颗粒物和有色溶解有机物的吸收系数明显大于无海带养殖季节,且春季海带养殖区水体的总吸收系数大于无海带养殖区;海底表层沉积物的再悬浮造成底层吸收系数较大,而在春季成熟期的海带汇聚较大量的有机物质导致中层藻类颗粒物吸收系数相对较高;参考波长向红波移动,QAA_v5算法能够较好地估算该区表层水体吸收系数,且在海带养殖季节水体组分会影响到更长的波段特征。本研究可为深入了解海带养殖对水体各组分浓度和分布、碳循环以及水生生态系统的结构和功能的影响提供参照,并有助于提高近岸水体组分的遥感反演精度。     

A multi‐technique study of the glacial stratigraphy of Co. Clare and Co. Kerry,southwest Ireland

A multi‐technique approach has been adopted in a study of the lithostratigraphy of glacial deposits in southwestern Ireland, including clast lithological analysis, fine sand geochemistry, low frequency mass specific susceptibility and fine sand calcium carbonate (equivalent) content. A revised lithostratigraphical scheme is suggested for the Quaternary glacial deposits of the region, together with a simple strategy that may be adopted for stratigraphical studies in other regions of southern Ireland. It appears that geochemical determinations via inductively coupled plasma–atomic absorption spectrometry are particularly useful in characterising and discriminating between till units within local stratigraphical studies and may be used to inform the applicability of other utilitarian techniques for use on a regional scale. Copyright © 2002 John Wiley & Sons, Ltd.     

HI absorption observations of two radio sources near the supernova remnant G 127.1 + 0.5

The compact source 0125 + 628 in the centre of the galactic supernova remnant G 127.1 + 0.5 has been re-observed in HI absorption using the Westerbork Synthesis Radio Telescope (WSRT). The outer arm HI absorption atV = -95km s^-1 has been confirmed. The absorption spectrum is similar to that of the nearby extragalactic source 0123 + 633. We discuss the arguments concerning an extragalactic origin of 0125 + 628 and conclude that it is most likely extragalactic and not an SS 433 type object. The National Radio Astronomy Observatory is operated by Associated Universities Inc. under contract with the National Science Foundation.     

A portable remote methane detector using an InGaAsP DFB laser

A portable remote methane detector based on infrared-absorption spectroscopy using an InGaAsP distributed-feedback laser is described. This equipment transmits a laser beam and detects a fraction of the backscatter reflected from the target. From this, the detector thereby measures the integrated methane concentration between the detector and the target. The equipment operator can easily detect methane clouds at a distance by hand-scanning the laser beam. To achieve a high sensitivity of detection, wavelength-modulation spectroscopy is applied to the infrared-absorption measurement for methane. The wavelength of the light source is modulated at a frequency of 10 kHz, and the center wavelength is stabilized at the center of the 2₃ band R(3) line of methane (1.65372 m). When used with typical targets at distances up to 10 m, the detector has a detection limit of less than 5 ppm-m. To the best of the authors knowledge, the detector is the only hand-held product capable of remote methane detection. Recently, this novel equipment was commercially introduced into the Japanese market as a product named the Portable Remote Methane Detector (PRMD). Some PRMD units were in research use for detecting methane emissions from garbage landfills, although the PRMD was mainly developed for remote detection of leaks from natural gas pipelines. The author expects that the PRMD could become the standard equipment for field measurements of methane emissions from land.     

锆石红外光谱在地质研究中的应用

以甘肃白银厂地区的7件锆石同位素年龄样品为例,根据其红外光谱中615cm-1吸收峰的高和半高宽度的比值,将锆石样品的变生程度量化,并将其分为晶质锆石、半变生锆石和变生锆石3类。参考相关资料,利用7件锆石样品的红外光谱特征对其铀钍含量和"红外年龄"做了估测,并将估测年龄与其U Th年龄和全岩Rb Sr年龄进行了比较和分析。