Numerical Simulations of Oscillation Modes of the Solar Convection Zone

The ACIS front-illuminated CCDs on board the Chandra X-Ray Observatory were damaged in the extreme environment of the Earth's radiation belts, resulting in enhanced charge transfer inefficiency (CTI). This produces a row dependence in gain, event grade, and energy resolution. We model the CTI as a function of input photon energy, including the effects of detrapping (charge trailing), shielding within an event (charge in the leading pixels of the 3x3 event island protects the rest of the island by filling traps), and nonuniform spatial distribution of traps. This technique cannot fully recover the degraded energy resolution, but it reduces the position dependence of gain and grade distributions. By correcting the grade distributions as well as the event amplitudes, we can improve the instrument's quantum efficiency. We outline our model for CTI correction and discuss how the corrector can improve astrophysical results derived from ACIS data.     

川滇菱形块体顺时针转动的构造学与古地磁学证据

川滇菱形块体内部受NE向丽江 -小金河断裂的切割 ,可进一步划分为川西北次级块体和滇中次级块体等南北 2个部分 ;各次级块体东边界断裂有规律地左旋滑动、西边界断裂的右旋滑动及其滑动速率值的差异 ,反映出新生代时期各次级块体作向SE的水平滑移叠加绕垂直轴顺时针转动的复合运动。其中 ,川西北次级块体SE向的水平滑移速率 5mm/a ,顺时针转动角速度 1 4°/Ma ;滇中次级块体SE向的水平滑移速率 3 5mm/a ,顺时针转动角速度约 1 5°/Ma。在滇中次级块体内部姚安、大姚、永仁、昆明北马街等地采集到约 90个古新世地层的定向样品 ,通过交变退磁和热退磁获得了它们各自的剩磁矢量 (实验磁偏角和磁倾角 ) ,由实测磁偏角与期望磁偏角相比可知川滇地区滇中次级块体中新世早期以来的顺时针转动累积量可达 30°～ 4 8°。次级块体的整体转动与块边活动断裂的左旋滑动符合左旋走滑断裂作用区块体作顺时针转动的运动学模式     

华北、扬子、塔里木地块显生宙古地磁数据

华北、扬子、塔里木地块显生宙古地磁数据程国良，孙宇航，孙青格，王立红（国家地震局地质研究所，北京１０００２９）继林金录（１９８７，１９８９）、翟永建等（１９８９）发表华北、扬子、塔里木和青藏等中国４大地质构造单元显生宙古地磁数据表之后，近几年来，又取     

新疆塔里木地台晚古生代古地磁极移曲线及其地质构造含义

用热退磁辅以交变退磁方法对采自塔里木盆地阿克苏地区四石厂剖面47个采样点518块标本进行了逐步磁清洗和测试。由本征剩磁方向统计得到塔里木地台晚古生代的古地磁极位置(晚泥盆世φ=10.5°S、λ=151.2°E;晚石炭世φ=52.2°N、λ=179.5°E;早二叠世φ=56.5°N,λ=190.1°E)。古地磁结果表明:塔里木地台在晚古生代是北方大陆的块体之一。从晚石炭世至早二叠世塔里木地台已和北方的哈萨克斯坦板块、西伯利亚地台、俄罗斯地台等连成一片,并且从中生代以来它们之间的相对位置没有发生过大规模的变动     

Titan's 5 micrometers spectral window: carbon monoxide and the albedo of the surface

We have measured the spectrum of Titan near 5 micrometers and have found it to be dominated by absorption from the carbon monoxide 1-0 vibration-rotation band. The position of the band edge allows us to constrain the abundance of CO in the atmosphere and/or the location of the reflecting layer in the atmosphere. In the most likely case, 5 micrometers radiation is reflected from the surface and the mole fraction of CO in the atmosphere is qCO=10(+10/-5) ppm, significantly lower than previous estimates for tropospheric CO. The albedo of the reflecting layer is approximately 0.07(+0.02/-0.01) in the 5 micrometers continuum outside the CO band. The 5 micrometers albedo is consistent with a surface of mixed ice and silicates similar to the icy Galilean satellites. Organic solids formed in simulated Titan conditions can also produce similar albedos at 5 micrometers.     

Growth of estuarine fish is associated with the combined concentration of sediment contaminants and shows no adaptation or acclimation to past conditions

We tested whether the growth rates of small benthic fish (Gillichthys mirabilis) in three southern California estuaries corresponded with the local concentrations of contaminants. Fish originating from each estuary were transplanted to cages in each estuary in two reciprocal transplant experiments. The growth rates of caged fish, and the size-distribution of natural populations, showed the same pattern of difference among estuaries. Twelve metals and organic contaminants occurred in bulk sediments at concentrations close to their individual ERL values, and a simple index of their combined concentration (the mean ERL quotient) was inversely correlated to the growth of caged fish. Metals in the water column occurred at lower concentrations, relative to toxicity thresholds, than those in sediments and were unrelated to fish growth. Fish used in the field caging experiments, and other fish held in the laboratory under constant conditions, showed no difference in growth according to their estuary of origin. Fish originating from different estuaries also showed no consistent differences in their tissue burden of organic contaminants. Our results thus suggested no genetic adaptation or physiological acclimation to the past contaminant regime, but revealed a possible association between fish growth rates and the combined concentration of multiple sediment contaminants.     

近两千年来的地磁极章动

地磁极章动是一个与地磁场起源和古地磁学中的轴向地心偶极子假说直接有关的问题。对于这一问题的研究,存在着各种不同的观点。本文采用了与上述研究者不同的方法,求出了近两千年来地磁极的章动轨迹。 一、方法 按一般的做法,只有在某个地点的磁倾角和磁偏角皆为已知的情况下才能求出当时的地磁极位置。但是,由于可供测量偏角的标本远比可供测量倾角的标本为罕见,因此,目前得     

“元谋人”的年代和松山早期事件的商榷

我们伟大的祖国幅员辽阔,资源丰富。我们伟大的人民勤劳勇敢,历史悠久。我国是世界上发现古人类化石最早、最丰富的国家之一。     

太阳罗盘在古地磁研究中的应用

引言 在强磁性岩石(如玄武岩)出露地区采集定向样品,使用太阳罗盘十分必要,因为这些岩石具有较强的剩磁,其附近显著的附加剩磁,使磁罗盘的指针与当地的地磁等偏线不一致,从而导致用磁罗盘测得的标志面倾向(或走向)与真实值出现差别。使用太阳罗盘则弥补了磁罗盘的不足。K.H.Creer等(1967)和李普等(1984)都曾对太阳罗盘的应用进行过理论分析,但他们对一些参数符号的选择和太阳方位角的确定过于繁琐,因此,使其广泛应用受到一定的限制,本文从满足古地磁工作需要出发,对理论推导过程做了简化,从而易于理解,另外,附录了一套计算程序,只需输入采样点的经、纬度、测量时间等5个参数,计算机即可