CCD photometry of five X-ray selected BL Lacertae objects

We present the results of the monitoring of a sample of 5 HBLs in the B, V and R bands during 2003–2008. All sources in our monitoring project show significant rapid optical variations, except 1ES 1959+650, however; for 1ES 1959+650, the gamma-ray variability on a timescale of ～7 hours has been observed by Holder et al. (Astrophys. J. 583:L9, 2003). Using these variability timescales, we estimate the black hole masses for each source with the Kerr black hole theory.     

Solar Intranetwork Magnetic Elements: Evolution and Lifetime

Based on Hinode SOT/NFI observations with greatly improved spatial and temporal resolution and polarization sensitivity, the lifestory of the intranetwork (IN) magnetic elements are explored in a solar quiet region. A total of 2282 IN elements are followed from their appearance to disappearance and their fluxes measured. By tracing individual IN elements their lifetimes are obtained, which fall in the range from 1 to 20 min. The average lifetime is 2.9±2.0 min. The observed lifetime distribution is well represented by an exponential function. Therefore, the e-fold characteristic lifetime is determined by a least-square fitting to the observations, which is 2.1±0.3 min. The lifetime of IN elements is correlated closely with their flux. The evolution of IN elements is described according to the forms of their birth and disappearance. Based on the lifetime and flux obtained from the new observations, it is estimated that the IN elements have the capacity of heating the corona with a power of 2.1×10²⁸ erg s⁻¹ for the whole Sun.     

Observed winds,turbulence, and dispersion in built-up downtown areas of Oklahoma City and Manhattan

Wind and tracer data from the Oklahoma City Joint Urban 2003 (JU2003) and the Manhattan Madison Square Garden 2005 (MSG05) urban field experiments are being analyzed to aid in understanding air flow and dispersion near street-level in built-up downtown areas. The mean winds are separately calculated for groups of anemometers having similar exposures such as “near street level” and “on building top”. Several general results are found, such as the scalar wind speed at street level is about 1/3 of that at building top. Turbulent standard deviations of wind speed components and temperature, and vertical fluxes of momentum and sensible heat, are calculated from sonic anemometers near street level at 20 locations in JU2003 and five locations in MSG05, and from two rooftop locations in MSG05. The turbulence observations are consistent with observations in the literature at other cities, although the JU2003 and MSG05 data are unique in that many data are available near street level. For example, it is found that the local (i.e., at the measuring height) averages about 1.5 and the local averages about 0.25 in the two cities, where is the standard deviation of vertical velocity fluctuations, is the friction velocity, and u is the wind speed. The ratio of temperature fluctuations to temperature scale, , averages about −3 in both cities, consistent with similarity theory for slightly unstable conditions, where is the standard deviation of temperature fluctuations, and is the temperature scale. The calculated Obukhov length, L, is also consistent with slightly unstable conditions near street level, even at night during JU2003. The SF₆ tracer concentration observations from JU2003 are analyzed. Values of for the continuous releases are calculated for each release and arc distance, where is the 30-min average arc maximum concentration, Q is the continuous source emission rate, and u is the spatial-averaged wind speed in the downtown area. The basic characteristics of the JU2003 plot of averaged agree reasonably well with similar plots for other urban experiments in Salt Lake City and London (i.e., at . A is found to be about 3 during the day and about 10 during the night.     

High-pressure granulite from Western Kunlun,northwestern China: Its metamorphic evolution,zircon SHRIMP U-Pb ages and tectonic implication

High-pressure mafic granulites occurring as lenticular bodies within garnet-amphibolites in Kangxiwar Fault have been first reported in this paper. The P-T conditions of two metamorphic stages were ob-tained using calibrated geothermal barometers and ThermoCalc Program. The peak metamorphic con-dition of these high-pressure granulites is about 760―820℃,1.0―1.2 GPa and the retrograde meta-morphic condition is about 620―720℃,0.7―0.8 GPa. The petrological studies show that they have a near-isobaric cooling P-T...     

Quantitative assessment of the spatial distribution of 239+240Pu inventory derived from global fallout in soils from Asia and Europe

Journal of Geographical Sciences - Due to the atmospheric nuclear weapon tests carried out, terrestrial environments have been extensively contaminated by global fallout of plutonium (Pu)...     

Source apportionment and distribution of atmospheric mercury in urban Beijing,China

The concentration of gaseous elemental mercury (GEM) in the atmosphere of urban Beijing was measured from October 2003 to September 2004 to investigate the origins and spatial-temporal variations of atmospheric Hg. The mean value of Hg concentration is 17.1 ng·m-3 (n=653). The atmospheric Hg data showed spatial-temporal variations throughout the duration of our observation. The maximum GEM concentration (53.7 ng·m-3) was observed at Gucheng in the western area of urban Beijing. The GEM concentrations increased from the north to the south of the studied area, and were higher in winter than in summer. The highest and lowest monthly averages of GEM concentrations were measured to be 23.3 and 4.1 ng·m-3 in January and July, respectively. In addition, GEM concentrations are higher in the daytime than at night in Autumn and from 14 March to 15 April, but daily GEM variation showed an inverse pattern from 22 April to 22 May. In winter, two peak values of GEM concentrations occurred at 13:30 and 21:30. Daily variation of GEM concentrations in summer was the lowest in the four seasons. Mercury from coal combustion was estimated to be the main source of anthropogenic emissions in Beijing from October 2003 to September 2004. Additionally, Hg emission from natural gas burning was estimated to be another dominant source of atmospheric Hg in Beijing.     

Fractal kinetic characteristics for dissolving and leaching processes of strontium residue

The pore structural characteristics of strontium residue were studied with the N₂ adsorption method (ASAP2010). The kinetic properties concerning dissolving and leaching strontium waste were described by determining the concentrations of Sr²⁺, Ba²⁺ and soluble sulphides in solutions. The results showed that the specific surface area and pore volume increased with decreasing granule diameter, and the micropore surface of the residue was fractal. In the dissolving and leaching processes of strontium residue, soluble ion concentrations increased with decreasing granule diameter of the residue, and the reaction dimension was lower than the fractal dimension of pore surface. Sr²⁺ and soluble sulphide concentrations significantly exceeded the defined standard values, while Ba²⁺ concentrations did not, either in the dissolving or leaching solutions. In addition, dissolving and leaching reactions selectively occurred on the micropore surface of strontium residue.     

松辽盆地徐家围子三维构造应力场数值模拟研究

本文采用有限元数值模拟的方法,以徐家围子断陷深层的重点勘探区域为研究对象,对深部构造应力场进行仿真。结果表明:研究区在断陷期的应力场以张性为主,局部表现为挤压性质;挤压比较强烈的区域多位于现今的构造高位置,徐西斜坡、丰乐低隆起和宋站凸起等地方相对明显;营城组沉积期间不一定发生过区域性的挤压运动,在左旋的张性环境下也可以形成挤压构造。     

龙感湖近百年来沉积物磷的时空分布特征及其人类活动影响

湖泊沉积物蓄积的磷在湖泊环境发生变化(如pH值、Eh改变)时,往往能释放到水体,形成湖泊内源释放,造成湖泊富营养化.因此了解湖泊沉积物磷的蓄积特征,对于湖泊环境的治理和保护有重要意义.通过长江中游龙感湖不同部位钻孔的210Pb、沉积物磷和其他环境指标分析表明,近百年来东部湖区沉积速率明显大于西部湖区,北部湖区略大于南部湖区,人类活动在20世纪50年代后期主要通过修建水库和闸坝,改变龙感湖水系结构,也改变了龙感湖的物源供给,因而西部湖区沉积速率略有放缓,东部湖区变化不明显.龙感湖沉积物磷的浓度空间上表现为东部高于西部,这与不同物源磷的背景值相关,时间序列上近百年来呈上升趋势,上世纪50年代以来上升趋势更为明显.在确定沉积物磷背景值的基础上,由于人类活动导致的磷的增加量表明,20世纪50年代开始人类活动导致沉积物磷的增加量持续上升,20世纪70年代末开始增加幅度更大,这一特征与人类活动的方式有关.     

云南武定荒箐铁铜多金属矿矿床成因

矿床产于断层破碎带中,受断层和地层层位控制,与迤纳厂矿床具有一定的相似性。铁矿为中低温热液裂隙充填型脉状矿床,而铜矿床应为沉积——变质型。