包头地区二次大雪过程的成因分析

文章应用常规资料,从天气环流形势演变、物理量等方面,对2000年1月10—11日包头地区普降大雪过程作了客观的分析,揭示了大雪过程的发生、发展机制,对今后分析大雪过程具有一定指导意义。     

电流对钋青霉菌吸附和固定铅离子的响应机制

重金属铅污染是一种主要的环境污染类型,对生态以及人类健康存在着极大的威胁。如何修复铅污染是目前亟待解决的关键性问题。在众多的铅污染修复方法中,微生物修复法具有独特的优势。本实验中所使用的钋青霉菌是已被验证的对铅具有高耐受度和高吸附率的优秀菌种。在此基础上,本实验的主要研究目的在于进一步提高该菌种对铅的吸附、固定能力。实验采用双室电解池体系,分组设置0.5 V至1.5 V的梯度槽压,以观察不同电压下电流对钋青霉菌生长环境及对铅离子吸附作用的影响。实验结果表明,电流既可能促进也可能抑制钋青霉菌对铅离子的吸附和固定作用,其作用结果与外加电压的大小有关,在1.0~1.25 V的最适电压区间下,电流能增强钋青霉菌对铅离子的吸附和固定能力。     

Purification, characterization and ELISA of metallothionein from red scorponifish, Sebastiscus marmoratus

INTRODUCTIONATislowKWCys-rich(aboutonethird)metal-bindingprotein,lackofaromaticaminoacidresidues.AThasbeenfoundinkidneysandliversofmanymammals,andalsoininvertebrates,microorganismsandplants.ThepresenceofanAT-likeproteinhasbeenfoundinanumberofaquaticorganisms,includingtheplaice(Overnelletal.,1977),rock-fish(Olafsonetal.,1974),goldfish(Marafant,1976),andcrabandshrimp(Olafsonetal.,1979).AThasbecomethesubjectofgreatInterestinrecentyearsduetotheirwideexistenceandmetalaffinity.Scientistsha…     

Comparison of short-term toxicity of 14 common phycotoxins (alone and in combination) to the survival of brine shrimp Artemia salina

Toxic harmful algal blooms(HABs) can cause deleterious effects in marine organisms, threatening the stability of marine ecosystems. It is well known that different strains, natural populations and growth conditions of the same toxic algal species may lead to different amount of phycotoxin production and the ensuing toxicity. To fully assess the ecological risk of toxic HABs, it is of great importance to investigate the toxic effects of phycotoxins in marine organisms. In this study, the short-te...     

JpGraph绘图类库在地震数据展示中的应用

天津市地震局在进行地震观测数据可视化发布工作中,采用PHP语言及JpGraph类库实现了前兆类观测数据在WEB页面中的图形化展示,扩展了PHP语言在行业数据发布与展示系统中的应用,本文主要阐述JpGraph类库的应用及在使用中遇到的问题.     

Frequency-dependent rupture process,stress change,and seismogenic mechanism of the 25 April 2015 Nepal Gorkha <Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> 7.8 earthquake

On 25 April 2015, an M _w 7.8 earthquake occurred on the Main Himalaya Thrust fault with a dip angle of ~ 7° about 77 km northwest of Kathmandu, Nepal. This Nepal Gorkha event is the largest one on the Himalayan thrust belt since 1950. Here we use the compressive sensing method in the frequency domain to track the seismic radiation and rupture process of this event using teleseismic P waves recorded by array stations in North America. We also compute the distribution of static shear stress changes on the fault plane from a coseismic slip model. Our results indicate a dominant east-southeastward unilateral rupture process from the epicenter with an average rupture speed of ~3 km s^?1. Coseismic radiation of this earthquake shows clear frequency-dependent features. The lower frequency (0.05–0.3 Hz) radiation mainly originates from large coseismic slip regions with negative coseismic shear stress changes. In comparison, higher frequency (0.3–0.6 Hz) radiation appears to be from the down-dip part around the margin of large slip areas, which has been loaded and presents positive coseismic shear stress changes. We propose an asperity model to interpret this Nepal earthquake sequence and compare the frequency-dependent coseismic radiation with that in subduction zones. Such frequency-dependent radiation indicates the depth-varying frictional properties on the plate interface of the Nepal section in the main Himalaya thrust system, similar to previous findings in oceanic subduction zones. Our findings provide further evidence of the spatial correlation between changes of static stress status on the fault plane and the observed frequency-dependent coseismic radiation during large earthquakes. Our results show that the frequency-dependent coseismic radiation is not only found for megathrust earthquakes in the oceanic subduction environment, but also holds true for thrust events in the continental collision zone.     

内蒙古索伦山蛇绿岩锆石U-Pb年代学、地球化学特征及其地质意义

为加深对中亚造山带东段晚古生代构造背景的认识,选取内蒙古索伦山蛇绿岩中较新鲜的玄武岩和辉长岩开展岩相学、年代学和地球化学研究。结果表明,玄武岩和辉长岩的LA-ICP-MS锆石U-Pb谐和年龄分别为(276.4±1.4) Ma和(273.9±3.3) Ma,形成于早二叠世。二者均为亚碱性拉斑系列,Mg^#分别变化于41～50和62～65之间,均低于幔源原生岩浆值;主量元素与SiO₂含量之间具有一定的线性关系,反映岩浆演化过程中分离结晶占主要地位。两种岩石的Th/La、Th/Ce和Lu/Yb值均低于大陆地壳的平均值,而与幔源岩浆的比值接近,推测岩浆演化过程中地壳混染的影响不大。稀土元素组成上,玄武岩表现为轻稀土亏损的N-MORB特征,可能起源于尖晶石二辉橄榄岩亏损地幔的5%～10%部分熔融;辉长岩具有轻稀土略亏损、整体平坦的稀土特征,但稀土元素总量明显比N-MORB更亏损,是源区熔融程度更大所致。此外,二者都富集K、Sr、Ba和Pb等大离子亲石元素而亏损Nb、Ta等高场强元素,具有岛弧岩浆特征,指示它们遭受了俯冲板片含水流体或者俯冲沉积物熔体的影响...     

Fe3+纳米胶体颗粒的光吸收边蓝移与溶液中Al/Fe比的关系

合成了n（Al）／n（Fe）和碱化度不同的45个聚合氯化铝铁（PAFC）样品,进行了光谱分析,结果显示光吸收边蓝移或红移以及Fe（Ⅲ）羟基氧化物和Al-Fe共聚体纳米胶体颗粒大小分布与溶液的Al／Fe比和碱化度（B=[OH]／[Al＋Fe]）密切相关。电镜观察和电子衍射分析表明：Al（Ⅲ）的加入使Fe（Ⅲ）羟基氧化物和Al-Fe共聚体纳米胶体颗粒变小、有序度降低是造成PAFE光吸收边蓝移和保持胶体颗粒在亚稳定状态下存在的重要原因。当n（Al）／n（Fe）〉8：2后,PAFC溶液中Fe（Ⅲ）羟基氧化物和Al-Fe共聚体胶体主要以〈10m的纳米颗粒形态存在,对应的光谱能级提高到26000cm^-1以上,且各种曰值下Fe^3＋的光谱能级趋于一致。这表明,在大量Al（Ⅲ）存在条件下,PAFE中Fe3^＋的所处的化学环境相似。点能谱分析显示,n（Al）／n（Fe）=4：6的样品中颗粒物的化学计量比最接近AlOOH,FeOOH,溶液的稳定性最差。     

Carbon and nitrogen isotope,and mineral inclusion studies on the diamonds from the Pozanti–Karsanti chromitite,Turkey

The Pozanti–Karsanti ophiolite (PKO) is one of the largest oceanic remnants in the Tauride belt, Turkey. Micro-diamonds were recovered from the podiform chromitites, and these diamonds were investigated based on morphology, color, cathodoluminescence, nitrogen content, carbon and nitrogen isotopes, internal structure and inclusions. The diamonds recovered from the PKO are mainly mixed-habit diamonds with sectors of different brightness under the cathodoluminescence images. The total δ¹³C range of the PKO diamonds varies between ??18.8 and ??28.4‰, with a principle δ¹³C mode at ??25‰. Nitrogen contents of the diamonds range from 7 to 541 ppm with a mean value of 171 ppm, and the δ¹⁵N values range from ??19.1 to 16.6‰, with a δ¹⁵N mode of ??9‰. Stacking faults and partial dislocations are commonly observed in the Transmission Electron Microscopy foils whereas inclusions are rather rare. Combinations of (Ca_0.81Mn_0.19)SiO₃, NiMnCo-alloy and nano-sized, quenched fluid phases were observed as inclusions in the PKO diamonds. We believe that the ¹³C-depleted carbon signature of the PKO diamonds derived from previously subducted crustal matter. These diamonds may have crystallized from C-saturated fluids in the asthenospheric mantle at depth below 250 km which were subsequently carried rapidly upward by asthenospheric melts.     

MODIS遥感监测滇池蓝藻水华分布

以中分辨率的MODIS数据作为遥感影像源,运用蓝藻水华在蓝波段、红波段和近红外波段的光谱特征,使用假彩色合成法（RGB：6-2-1）和归一化植被指数法对滇池的蓝藻水华进行遥感监测。通过星地同步试验,证明了该两种方法的正确性。其中假彩色合成法通过色彩差异表现蓝藻水华,具有视觉效果较好的优点,归一化植被指数法则以数值大小的方式区别水华浓度,该方法建立反演模型后可用于定量研究。