超高压对面顶压机与钠长石分解反应实验

变质相系的概念把变质作用的物化条件与地壳演化的某些控制因素联系起来,强调了不同大地构造环境所具的变质作用类型及特征。都城秋穗将变质作用分为低压型、中压型及高压型三种。高压变质作用以硬玉、硬柱石和蓝闪石的出现为特征,特别是与石英共生的硬玉,是公认的高压矿物,并把钠长石分解为硬玉与石英这一变质反应作为确定高压相系的临界反应。     

层状土中的轴向载荷桩

本文运用严密的弹性荷载传播理论，依据有效应力对层状土中轴向载荷桩的性状进行了研究。根据Ｍｕｋｉ和Ｓｔｅｍｂｅｒｇ的方法，将要研究的问题分解为具有层状土弹性性质的扩展土层和其特性由杨氏模量来表示的一根虚拟桩两个系统来进行研究，而虚拟桩的杨氏模量等于真实桩的杨氏模量与相应土层的杨氏模量之差。     

Black Hole Mergers in the Universe

We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-Ray Observatory. These spectra reveal many narrow absorption lines from the H-like and He-like ions of O, Ne, Mg, Si, S, and Ar as well as Fe xvii-Fe xxi L-shell lines. We have also identified several weak emission lines, mainly from O and Ne. The absorption lines are blueshifted by a mean velocity of approximately 440+/-200 km s-1 and are not resolved, indicating a velocity dispersion within the absorbing gas of a few hundred kilometers per second or less. We measure the lines' equivalent widths and compare them with the predictions of photoionization models. The best-fitting model has a microturbulence velocity of 150 km s-1 and a hydrogen column density of 1.3x1022 cm-2. The measured blueshifts and inferred velocity dispersions of the X-ray absorption lines are consistent with those of the strongest UV absorption lines observed in this object. However, simple models that propose to strictly unify the X-ray and UV absorbers have difficulty explaining simultaneously the X-ray and UV absorption-line strengths.     

末次冰川作用期间南极冰盖的千年尺度不稳定性

北大西洋沉积物中的冰筏载事件提供了末次冰川作用期间劳伦泰德冰盖 (ＬＩＳ)千年尺度不稳定性的证据。然而 ,尽管其与自然和人为的气候变化问题有关 ,但还是没有确定南极冰盖 (ＡＩＳ)在这些时间尺度上的状态。大部分西南极冰盖 (ＷＡＩＳ)建立于海平面以下 ,因此可能易受海平面和气候的干扰 ,这种内在的不稳定性也是末次冰川作用期间劳伦泰德冰盖的特征 ,其建立于哈得孙海峡区域的海平面以下。在全冰川环境下 ,西南极冰盖大约比现今西南极冰盖大２／３ ,海平面低约１２０ｍ ,南极洲周围边缘海的搁浅冰架更加广泛。因此 ,更新世南极冰盖历…     

冀东元古界朱杖子群原岩建造特征及其形成条件

河北省青龙县位于秦皇岛市西北约七十公里的燕山山脉东段。本文所涉及的朱杖子群主要是指分布于河北省青龙县城以东的岳家杖子—东汗沟一带,北以大巫岚—大张杖子为界,南至杨台子—老爷庙。面积约200平方公里。 区内变质岩层走向及构造线方向为北东—南西向,倾向北西,倾角多数为50°—60°,局部较陡,可达70°—80°。层理和片理方向基本一致(图1)。原生结构构造比较发育,     

冀东含紫苏辉石的变质岩与变质作用的关系

河北迁安麻粒岩相铁矿区含紫苏辉石的变质岩可分为三大类:A、糜棱岩状含磁铁(黑云母)石英紫苏辉石岩、二辉磁铁石英岩;B、片麻状(块状)紫苏花岗质麻粒岩;C、黑云(角闪)麻粒岩、二辉麻粒岩。 A类岩石主要分布于铁矿区的韧性变形带中心。韧性变形带宽10—50m,其中夹有不同规模的角闪磁铁石英岩透镜体。该类岩石的矿物组合为:Hy+Q±Mt±Bi;Hy+Q+Mt±     

The use of kelp sieve tube sap metal composition to characterize urban runoff in southern California coastal waters

This study introduces an innovative method for biomonitoring using giant kelp (Macrocystis pyrifera) sieve tube sap (STS) metal concentrations as an indication of pollution influence. STS was sampled from fronds collected from 10 southern California locations, including two reference sites on Santa Catalina Island. Using ICP-MS methodology, STS concentrations of 17 different metals were measured (n = 495). Several metals associated with pollution showed the highest STS concentrations and most seasonal variation from populations inside the Port of Los Angeles/Long Beach. Lowest concentrations were measured at less-urbanized areas: Santa Catalina Island and Malibu. Some metals showed a spatial gradient in STS metal concentration with increasing distance from point sources (i.e. Los Angeles River). Cluster analyses indicate that polluted seawater may affect kelp uptake of metals essential for cellular function. Results show that this method can be useful in describing bioavailable metal pollution with implications for accumulation within an important ecosystem.     

Small plastic debris changes water movement and heat transfer through beach sediments

We investigated the physical properties of beaches contaminated with plastic fragments. We compared sediment cores from Hawai‘i Island’s Kamilo Beach, notable for plastic accumulation, to cores from a nearby beach. Compared to the nearby beach, Kamilo sediments contained more plastics (up to 30.2% by weight), were coarser-grained, and were more permeable (t-test, p < 0.0001). 85% of the fragments were polyethylene, and 95% were concentrated in the top 15 cm of the cores. We constructed artificial cores of standardized grain size and varying plastic-to-sediment ratios. Adding plastic significantly increased the permeability (ANOVA, p = 0.002), which was partially attributed to the fragments increasing the mean grain size. Sediments with plastic warmed more slowly (16% maximum decrease in thermal diffusivity), and reached lower maximum temperatures (21% maximum increase in heat capacity). These changes have a variety of potential effects on beach organisms, including those with temperature-dependent sex-determination such as sea turtle eggs.