On a new cluster of H<Subscript>2</Subscript>O maser spots in the source ON2

We present the results of our observations of the H₂O maser emission toward the complex source ON2 associated with an active star-forming region. The observations were performed in a wide range of radial velocities, from ?75 to 90 km s^?1. We have detected an emission with flux densities of 9.2, 4, and 26 Jy at radial velocities of ?33.5, ?24.4, and ?18.8 km s^?1, respectively, at which no emission has been observed previously. The detected emission is most likely associated with a hitherto unknown cluster of maser spots located between the northern (N) and southern (S) components of the source ON2 (closer to the northern one). This cluster may be associated with one of the three CO molecular outflows in the ON2 region. We have also detected an emission at ?22 and ?14.5 km s^?1 in N and at 12.6 km s^?1 in S, which has extended significantly the velocity ranges of the maser emission in these sources and allowed their models to be improved.     

Static pressure of hot gas: Its effect on the gas disks of galaxies

The static pressure of the hot gas that fills clusters and groups of galaxies can affect significantly the volume density and thickness of the gas disks in galaxies. In combination with the dynamic pressure, the static pressure allows several observed peculiarities of spiral galaxies surrounded by a hot medium to be explained.     

Merging time-scales of stellar subclumps in young star-forming regions

Recent observations and hydrodynamical simulations of star formation inside a giant molecular cloud have revealed that, within a star-forming region, stars do not form evenly distributed throughout this region, but rather in small subclumps. It is generally believed that these subclumps merge and form a young star cluster. The time-scale of this merging process is crucial for the evolution and the possible survival of the final star cluster. The key issue is whether this merging process happens faster than the time needed to remove the residual gas of the cloud. A merging time-scale shorter than the gas-removal time would enhance the survival chances of the resulting star cluster. In this paper, we show by means of numerical simulations that the time-scale of the merging is indeed very fast. Depending on the details of the initial subclump distribution, the merging may occur before the gas is expelled from the newly formed cluster via either supernovae or the winds from massive stars. Our simulations further show that the resulting merger objects have a higher effective star formation efficiency than the overall star-forming region and confirm the results that mass-segregated subclumps form mass-segregated merger objects.     

机载激光点云与影像联合测图的技术进展和趋势

本文通过对激光点云与光学影像联合测图所涵盖的关键技术进展进行分析,重点指出目前激光扫描仪进行测绘生产所面临的主要挑战。结合激光扫描技术与光学影像融合后的数据特点与实际行业生产需求,简要探讨了未来激光测图技术发展的趋势及新产品体系构建设想,以期对激光扫描软硬件系统在相关行业应用推广中具有一定参考意义。     

激光加工技术在珠宝首饰业中的应用

激光加工技术在珠宝首饰业中的应用越来越广泛。介绍了该技术的基本特点以及其在珠宝首饰业中的典型应用现状。这些技术涉及激光焊接、激光快速原型技术、激光打标、激光雕刻和激光切磨钻石等领域。激光焊接比传统的焊接技术具有显著的优点;快速原型技术的引入大大缩短了从首饰图样到制出原版的时间;激光打标和激光雕刻的使用丰富了首饰表面处理的手段,可进一步满足首饰个性化需求;激光切磨钻石原石可达到最小的损耗。激光加工技术在珠宝首饰业中发挥着越来越重要的作用。     

激光探针等离子体质谱法（LAM—ICPMS）用于年龄锆石U—Pb定年

利用激光探针等离子体普（ＬＡＭ－ＩＣＰＭＳ）技术对中生代锆石进行了详细的２０６Ｐｂ／＾２３８定年研究。采用线扫描（Ｌｉｎｅ ｓｃａｎ）进样法减小了传统的剥深（Ｄｅｐｔｈ ｐｒｏｆｉｌｅ）进样法所引起的激光熔蚀分异效应;优化仪器参数可三ＩＣＰ－ＭＳ对Ｐｂ和Ｕ的质量歧视效应。测得了精确的＾２０６Ｐｂ／＾２３８Ｕ比值及年龄。研究结果表明,均匀颗粒锆石的＾２０６Ｐｂ／＾２３８Ｕ比值测量精度为２％～１０％,     

Rayleigh Scattering and Laser Spot Elongation Problems at ALFA

This article describes the qualitative effects of LGS spot elongation and Rayleigh scattering on ALFA wavefront sensor images.An analytical model of Rayleigh scattering and a numerical model of laser plume generation at the altitude of the Na-layer were developed. These models, integrated into ageneral AO simulation, provide the sensor sub-apertureimages. It is shown that the centroid measurement accuracyis affected by these phenomena. The simulation was made both for the ALFA system and for the VLT Nasmyth Adaptive Optics System (NAOS).     

Thermal analysis in the laser-heated diamond anvil cell

A new technique actively controls thermal radiation and monitors sample properties during laser-heating in a diamond anvil cell. The technique can be described as a qualitative application of thermal analysis. Discontinuities in temperature, laser power, visible thermal radiation, or in their derivatives as functions of time can be associated with the enthalpy of phase transitions (such as melting) or with changes in maternal properties (such as emissivity).The technique is illustrated with melting experiments on iron-magnesium-silicate perovskite. Temperature corrections associated with these experiments are discussed and the results are briefly reviewed.     

A Comparative Study of Five Reference Materials and the Lombard Meteorite for the Determination of the Platinum‐Group Elements and Gold by LA‐ICP‐MS

A range of independently characterised reference materials (RMs) for LA‐ICP‐MS, used for the determination of the platinum‐group elements (PGE) and Au in a sulfide matrix, were analysed and compared: 8b, PGE‐A, NiS‐3, Po727‐T1, Po724‐T and the Lombard meteorite. The newly developed RM NiS‐3 was used as the RM for the calibration of all LA‐ICP‐MS analyses and the measured concentrations of the other RMs compared against their published concentrations. This data were also used to assess the consistency of concentrations calibrated against the different RMs. It was found that Po727‐T1 and 8b produced results that were comparable, within uncertainty, for all elements. Po727‐T1 also produced consistent results with NiS‐3 for all elements. All other RMs showed differences for some elements, especially Ru in Po724‐T, and Os, Ir and Au in PGE‐A. The homogeneity of the PGE and Au in each RM was assessed, by comparing the precision of multiple LA‐ICP‐MS spot analyses with the average uncertainty of the signal. Po724‐T, Po727‐T1 and the Lombard meteorite were found to be homogeneous for all elements, but 8b, PGE‐A and NiS‐3 were heterogeneous for some elements. This is the first direct comparison between a range of independently characterised PGE and Au LA‐ICP‐MS RMs.