Letter to the editor A strange cloud in the Arctic summer stratosphere 1998 above Esrange (68°N), Sweden

When the University of Bonn lidar on the Esrange (68°N, 21°E), Sweden, was switched on in the evening of July 18, 1998, a geometrically and optically thin cloud layer was present near 14 km altitude or 400 K potential temperature, where it persisted for two hours. The tropopause altitude was 4 km below the cloud altitude. The cloud particles depolarized the lidar returns, thus must they have been aspherical and hence solid. Atmospheric temperatures near 230 K were approximately 40 K too high to support ice particles at stratospheric water vapour pressures of a few ppmv. The isentropic back trajectory on 400 K showed the air parcels to have stayed clear of active major rocket launch sites. The air parcels at 400 K had travelled from the Aleutians across Canada and the Atlantic Ocean arriving above central Europe and then turned northward to pass over above the lidar station. Parcels at levels at ±25 K from 400 K had come from the pole and joined the 400 K trajectory path above eastern Canada. Apparently the cloud existed in a filament of air with an origin different from those filaments both above and below. Possibly the 400 K level air parcels had carried soot particles from forest wild fires in northern Canada or volcanic ash from the eruption of the Korovin Volcano in the Aleutian Islands.     

天水地震区深源岩石在1000MPa高压下的状态参数特征

本文重点介绍了天水地震区产出的深源岩石在１０００ＭＰａ高压下，测得的岩石的密度、纵横波速度和计算的波阻抗随压力的变化。发现不同时期产出的不同种类的深源岩石，它们的高压状态参数值变化范围很窄。压力上升到４００ＭＰａ以后，岩石的密度、纵横波速度的变化很小，几乎观测不到其变化。本文简单地讨论了岩石在４００ＭＰａ以上高压状态下，上述参数值变化不大的原因，并对４００ＭＰａ压力下取得的高压状态参数值做了实用误差分析，结果表明：在不考虑温度情况下，该压力下获得的状态参数值在实际应用中完全可以代替更高压力状态下（４００ＭＰａ－２０００ＭＰａ）的测量值。因此４００ＭＰａ特征压力下取得的岩石状态参数值对人工地震测深解释和重力解释仍是有参考意义的。     

高温高压下石英方解石断层带的摩擦滑动性状

在不同的温度、压力条件下进行了含石英和方解石断层泥标本的摩擦实验。结果表明,石英断层带的摩擦强度对压力的响应直到400℃都很明显,对温度的响应在高温(高于400℃)时才明显;方解石断层带的摩擦强度对温度很敏感,对围压的响应只在低温(200℃)时才明显;随温度升高,石英和方解石断层带均由粘滑转变为稳滑,但前者的转换界限在400℃到500℃之间,而后者在200℃到300℃之间。显微观察表明,上述差异归因于其具体变形机制的差别。      

Variations of Strength,Resistivity and Thermal Parameters of Clay after High Temperature Treatment

This paper reports the variations of strength, resistivity and thermal parameters of clay after high-temperature heating. Experiments were carried out to test the physical properties of clay heated at temperatures ranging from room temperature to 800°C in a furnace. The experiment results show that below 400°C the uniaxial compressive strength and resistivity change very little. However, above 400°C, both increase rapidly. At a temperature under 400°C, the thermal conductivity and specific heat capacity decrease significantly. The thermogravimetric analysis (TG) and differential scanning calorimeter (DSC) test indicate that a series of changes occur in kaolinite at temperatures from 400 to 600°C, which is considered the primary cause of the variation of physical and mechanical properties of clay under high temperatures.     

Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides

The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400 mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400 mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400 mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300 mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.     

Ground penetrating radar antennae frequencies and transmitter powers compared for penetration depth,resolution and reflection continuity1

Twelve ground penetrating radar (GPR) experiments were conducted on the modern, wave-influenced William River delta, on the Southern shore of Lake Athabasca in northern Saskatchewan, Canada. The delta is a well-sorted, quartzoserich, clean, sand-dominated, water-saturated geomorphic feature which provided an ideal site to test GPR. Penetration depths, resolution and continuity of reflections were compared for different antennae frequencies (25, 50, 100, 200 MHz) and transmitter powers (pulser voltage: 400 V, 1000 V). The data show significant variations in vertical resolution from 0.15 m to 0.76 m (200-25 MHz), depth of penetration from 14 m-28 m (200-25 MHz), and continuity of reflections. Increasing the transmitter power from 400 V to 1000 V increases the depth of penetration by 5 to 14% and improves the continuity of reflections with little effect on the resolution.     

Seismic evidence for a metastable olivine wedge in the subducting Pacific slab under Japan Sea

We apply a forward-modeling approach to high-quality arrival time data from 23 deep earthquakes greater than 400 km depth to investigate the detailed structure of the subducting Pacific slab beneath the Japan Sea. Our results show that a finger-like anomaly exists within the subducting Pacific slab below 400 km depth, which has a P-wave velocity 5% lower than the surrounding slab velocity (or 3% lower than that of the normal mantle), suggesting the existence of a metastable olivine wedge (MOW) in the slab. The MOW top and bottom depths are 400 and 560 km, respectively. The MOW is estimated to be about 50 km wide at 400 km depth and close to the slab upper boundary. At 560 km depth the MOW is located at about 25 km below the slab upper boundary. Most of the deep earthquakes are located in the MOW. Our results favor transformational faulting as the mechanism for deep earthquakes.     

Development of Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Trace Lead in Water

A new method for determining lead (Pb) content was developed by dispersive liquid–liquid microextraction based on the solidification of floating organic droplets followed by flame atomic absorption spectrometry. Under optimum conditions, the calibration graph was linear within the Pb content range of 8.43–400 µg L^?1 with a detection limit of 2.53 µg L^?1. The relative standard deviation for 10 replicate measurements of 20 and 400 µg L^?1 of Pb were 3.41 and 2.78%, respectively. The proposed method was assessed through the analysis of certified reference water and recovery experiments.     

有机质对纳米级磁铁矿热稳定性的影响

单畴磁铁矿颗粒是地质样品中最重要的磁性载体,其稳定性一直备受关注.为了认识有机质对纳米级磁铁矿颗粒热稳定性的影响,本文对比研究了趋磁细菌AMB-1合成的单畴磁铁矿分别在全细胞中和经去胞提纯后的纯化磁小体中的热磁性质,以及热处理后样品的磁滞参数和低温磁性的变化.发现仅有磁小体膜包裹的纯化磁小体中单畴磁铁矿热稳定性极强,而全细胞中的单畴磁铁矿加热过程中发生了显著的热变化:磁铁矿在约270℃即开始转化,400℃以前几乎完全被有机质还原为顺磁性物质;同时在400℃以前,有机质的还原作用与有机质热分解引起磁小体链的坍塌,共同导致了样品矫顽力(B_c)、剩磁矫顽力(B_cr)和剩磁比(M_rs/M_s)的减小,以及矫顽力比(B_cr/B_c)的增加. 我们的实验结果清楚地表明,当地质样品中含有较多有机质组分并受热事件影响时,其中的单畴磁铁矿难以得到保存.     

Broadband Registration of High-Frequency Seismic Noise for Studying Tidal Effects

The possibility of registering high-frequency seismic noise in a broadband frequency range (f = 5–400 Hz) has been considered. The use of an accelerometer on based on the S mode of bending vibrations increases the sensitivity and expanses the frequency range. The operating principle of the accelerometer and its main technical characteristics have been described. Pilot registration of seismic noise was organized at Nachiki seismic station in Kamchatka. The comparative results of tidal effects in seismic noise have been presented according to the data of the broadband accelerometer (f = 5–400 Hz) and resonance sensor (f₀ = 30 Hz) during long-term registration on a common base.     

Influence of solar activity on variations in the density of the Earth’s upper atmosphere

This article studies long-period variations in the Earth’s upper atmosphere density over several solar activity cycles, using long-term data on the evolution of motion of three artificial satellites (Intercosmos-19, Meteor-1-2, and Cosmos-1154) in orbits at heights of 400–1000 km. The time interval when the satellites were in the orbits covered three solar activity cycles (partly the 21st, completely the 22nd, and partly the 23rd). It is found that the variations in the average density of the upper atmosphere at heights of 400–600 km in the 1980–2000 period were governed by the changes in the solar activity level.     

亚稳态橄榄石对俯冲带负浮力的影响及其动力学意义

利用有限元方法,计算了不同俯冲速度及热传导系数俯冲岩石层的负浮力.在h-lt;400km和h-gt;740km的深度范围,低温高密俯冲带的负浮力随深度单调增加.因为尖晶石相到后尖晶石相的相变有负的克兰帕龙斜率,俯冲带冷的物质在660km间断面以下不到100km的深度范围内仍以低密度的低压物质相存在.所以在该深度范围,俯冲带受到了周围地幔阻止其插入下地幔的浮力作用.在400km-lt;h-lt;660km深度范围,由于受橄榄石相变的影响,不同计算模型负浮力随深度的变化有明显的不同.对于可能的相变动力学模型,亚稳态橄榄石的存在使负浮力随深度的增加值减小.其作用是不利于俯冲带直接穿透660km间断面,并引起该深度范围俯冲带沿俯冲方向压应力分布的变化.     

Effects of polychlorinated biphenyls on liver function and sexual characteristics in Japanese medaka (Oryzias latipes)

The effects of polychlorinated biphenyls (PCBs) on liver function and their differences between sexes were analyzed in Japanese medaka (Oryzias latipes) exposed to PCB126 or Kanechlor-400 (KC-400) using microarray. PCB exposure induced vitellogenin 1 expression in female medaka while suppressing choriogenin genes, which suggests that the effects of PCBs on estrogen-responsive genes do not occur directly through an estrogen receptor-mediated pathway. Reduction of androgen receptor alpha expression was also observed, and the gene expression pattern in PCB-exposed males changed to become more similar to that of females. Furthermore, changes in glycolysis-related genes indicate that PCB exposure might enhance glucose production via gluconeogenesis in the liver of medaka. Taken together, our results suggest that PCBs disrupt the endocrine system, especially androgen function, and may have the potential to cause demasculinizing effects. Additionally, induction of gluconeogenesis might be a response to maintain glucose levels consumed as a result of PCB exposures.     

Effects of polychlorinated biphenyls on liver function and sexual characteristics in Japanese medaka (Oryzias latipes)

The effects of polychlorinated biphenyls (PCBs) on liver function and their differences between sexes were analyzed in Japanese medaka (Oryzias latipes) exposed to PCB126 or Kanechlor-400 (KC-400) using microarray. PCB exposure induced vitellogenin 1 expression in female medaka while suppressing choriogenin genes, which suggests that the effects of PCBs on estrogen-responsive genes do not occur directly through an estrogen receptor-mediated pathway. Reduction of androgen receptor alpha expression was also observed, and the gene expression pattern in PCB-exposed males changed to become more similar to that of females. Furthermore, changes in glycolysis-related genes indicate that PCB exposure might enhance glucose production via gluconeogenesis in the liver of medaka. Taken together, our results suggest that PCBs disrupt the endocrine system, especially androgen function, and may have the potential to cause demasculinizing effects. Additionally, induction of gluconeogenesis might be a response to maintain glucose levels consumed as a result of PCB exposures.     

应用经验正交函数估算顶部电离层电子密度剖面

本文基于IRI模型、地面数字测高仪和GNSS TEC数据,提出了一种利用经验正交函数(Empirical Orthogonal Function,简称EOF)估算顶部电离层电子密度剖面的方法,并将其应用于美国Millstone Hill测高仪和GNSS数据以估算顶部电离层电子密度剖面.通过将估算的临界频率、峰值高度、400km以上电子密度分别与测高仪实测临界频率、测高仪实测峰值高度以及非相干散射雷达实测400km以上电子密度作对比以对方法的有效性进行验证.统计结果显示估算临界频率、峰值高度与测高仪实测数据基本一致,400km以上估算电子密度相较于非相干散射雷达实测的绝对误差平均值仅是测高仪推算400km以上电子密度绝对误差平均值的一半左右.所以本文提出的方法可以更加精确地估算顶部电离层电子密度.     

Elastic Parameters of West Bohemian Granites under Hydrostatic Pressure

—The West Bohemian seismoactive region is situated near the contact of the Moldanu bian, Bohemian and Saxothuringian units in which a large volume is occupied by granitoid massifs. The spatial distribution of P-wave velocities and the rock fabric of five representative samples from these massifs were studied. The P-wave velocities were measured on spherical samples in 132 independent directions under hydrostatic pressure up to 400 MPa, using the pulse-transmission method. The pressure of 400 MPa corresponds to a depth of about 15 km in the area under study. The changes of P-wave velocity were correlated with the preferred orientations of the main rock fabric elements, i.e., rock forming minerals and microcracks. The values of the P-wave velocity from laboratory measurements on granite samples fit the velocity model used by seismologists in the West Bohemian seismoactive region.     

开发信息新价值及其新领域—记第47届国际文献与信息联合会大会

第４７届国际文献与信息联合会大会于１９９４年１０月２－９日在日本大宫市召开，来自世界各国的代表４００余人参加了会议。本文从五个方面反映了这次大会的概况。     

宁波台DD－1记录近震震相分析

以宁波地震台ＤＤ－１短周期仪器记录到的震中距４００ｋｍ左右的地震为例，讨论了该范围近震的震相分析问题。认为在地壳平均厚度约３０ｋｍ的地区的台站，当震中距在４００ｋｍ左右时Ｐ与Ｐｎ、与Ｌｇ差不多同时到达，使震相分析复杂化。指出可以用分析体波或面波的方法来加以确定地震的各项参数。     

Coccolith chemistry reveals secular variations in the global ocean carbon cycle?

The mismatch between the 100 and 400 k.y. components of Pleistocene climate and the relative power of those terms from the eccentricity of the Earth's orbit remains a challenge to the Milankovitch hypothesis. Coccolithophores have the potential to respond to parameters of orbital forcing other than insolation, and, as a critical component of the ocean carbon cycle, can act to modify the climate response. The first direct comparison of coccolith fraction Sr/Ca, alkenone abundance and automated coccolithophore counts, shows that CF Sr/Ca is largely driven by changing production of bloom species, with unusually high Sr/Ca ratios. The periods of high CF Sr/Ca and high bloom production mark periods of high global coccolithophore production, which correlate inversely with the low amplitude 100 and higher amplitude 400 k.y. eccentricity orbital frequency. ∼ 400 k.y. cycles of coccolithophore bloom production correspond to periods of enhanced carbonate accumulation in some parts of the ocean, deep ocean dissolution in others, positive shifts in global ocean δ¹³C, and acmes of Gephyrocapsa caribbeanica and Emiliania huxleyi. The link between production of coccolithophore blooms and eccentricity may be due to orbital control of silica leakage from the Southern Ocean, to the orbitally defined inverse correlation between insolation and growing season length and the asymptotic growth response to these parameters, or to changes in nutrient input from weathering. During the Pleistocene, the eccentricity induced coccolithophore acmes have no apparent influence on atmospheric carbon dioxide (pCO₂) due to the shift towards small bloom coccolithophores, or to coupling with increased diatom productivity, or the ballast effect of the calcium carbonate rain, such that Pleistocene climate has no significant variance at the largest amplitude eccentricity forcing of 400 k.y. Coccolithophores and their influence on the carbon cycle may act as a filter between the incident orbital forcing and resultant climate.     

长江中游湖泊CDOM光学特性及其空间分布对比

根据2007年秋季洪湖、东湖和梁子湖的调查结果,分析了长江中游3个典型湖泊CDOM光学特性及其空间分布差异.结果表明:(1)CDOM吸收系数在洪湖最高,梁子湖最低;(2)在洪湖,CDOM吸收系数受陆源影响较大,与悬浮泥沙浓度呈现较好正相关关系,而在梁子湖,CDOM吸收系数主要受到浮游植物降解贡献,与叶绿素浓度具有显著的正相关关系;(3)洪湖与东湖指数函数斜率S值变化不大;梁子湖CDOM吸收系数空间分布差异较大,指数函数斜率S值与400nm波段CDOM吸收系数ag(400)显著负相关.在建立梁子湖CDOM遥感反演模型时,应引入上述指数甬数斜率S值与400nm波段CDOM吸收系数之间的线性函数,对CDOM吸收系数的指数模型进行优化.