地气测量在内蒙老羊壕金矿区的某些试验成果   总被引：3，自引：0，他引：3  

史长义  张金华  刘应汉  黄笑梅  黄增芳 《物探与化探》1997,(4)

以内蒙老羊壕金矿区为试验基地 ,引进抽气法地气测量 ,探讨了地气测量在内蒙干旱荒漠区寻找浅覆盖区隐伏金矿床的有效性。并以试验资料为依据 ,初步探讨了抽气法地气测量中的若干问题 ,指出了抽气法地气测量中存在微尘颗粒干扰。对寻找隐伏金矿床的多元素地气测量 ,采用经 0 .2 2 μm微孔滤膜过滤泡沫塑料吸附为好。已有资料显示可能有超微粒 (接近纳米级 )物质自深部矿体迁移上来  相似文献   

Hg~(2+)对水鳖(Hydrocharis dubia)叶片生理生化及超微结构的毒害效应     

郝怀庆  施国新  杜开和  徐勤松 《湖泊科学》2001,(2)

研究了不同浓度Hg2 +对水鳖叶片光合放氧速率、呼吸速率、细胞膜透性、硝酸还原酶活性以及超微结构的毒害影响 .结果表明 ,随着Hg2 +浓度的增加 ,水鳖叶片的光合放氧速率逐渐下降 ,呼吸速率、硝酸还原酶活性先升后降 ,而细胞膜透性则逐渐上升 .电镜观察发现 ,水鳖叶细胞遭受Hg2 +毒害初期 ,染色质凝集 ,叶绿体中类囊体片层以及线粒体嵴突膨胀 .随着叶细胞遭受毒害程度的加深 ,核膜破裂 ,染色质与核质消失 ,叶绿体膨胀解体 ,线粒体空泡化  相似文献   

Lysosomal Membrane Stability and Metallothioneins in Digestive Gland of Mussels (Mytilus galloprovincialis Lam.) as Biomarkers in a Field Study     

S. Petrovi&#x;  B. Ozreti&#x;  M. Krajnovi&#x;-Ozreti&#x;  D. Bobinac 《Marine pollution bulletin》2001,42(12)

The lysosomal membrane destabilization and the metallothionein content in the digestive gland cells of mussels (Mytilus galloprovincialis Lam.), collected along the east coast of the North Adriatic (Istrian and Kvarnerine coast, Croatia), were examined over a period of four years (1996–1999). The lysosomal membrane stability, as a biomarker of general stress, showed that the membrane labilization period in mussels from polluted, urban- and industrial-related areas was significantly decreased (p<0.05) when compared to mussels from control, clean sea water sites. In the harbour of Rijeka, the most contaminated site, the lysosomal membrane stability was reduced by more than 70% compared to the control. This method also proved to be a useful biomarker for detection of additional stress caused by short-term hypoxia that occurred once during this study inside the polluted and periodically quite eutrophic Pula Harbour. The concentration of metallothioneins in the mussel digestive gland, as a specific biomarker of exposure to heavy metals, did not reveal significant differences (p<0.05) between sites covered by this study.  相似文献   

From surface electrical properties to spontaneous potentials in porous media   总被引：1，自引：0，他引：1  

A. Revil  M. Darot  P. A. Pezard 《Surveys in Geophysics》1996,17(3):331-346

This paper deals with the electrical double layer and the related properties of porous media. In particular, the electrical conductivity, the streaming potential, and the membrane potential are described in a self-consistent set of equations. All these properties are shown to be governed by fluid-matrix interface properties, as well as four geometrical parameters.  相似文献   

Strain segmentation and lateral membrane deformation rate of the subducted Ryukyu slab     

LingYun  Chiao 《Island Arc》1993,2(2):94-103

Abstract Focal mechanisms of intermediate-depth earthquakes within the subducted Ryukyu slab indicate a systematic pattern of down-dip extension in the northern part under Kyushu. These mechanisms switch rapidly around the Tokara channel to down-dip compression in the southern part toward Taiwan. This intriguing pattern of strain segmentation, together with the differences between the slab geometry of the northern and southern parts, has raised the question of whether stress segmentation, as defined possibly by a tear fault, might exist in the slab. However the Ryukyu trench has a concave oceanward shape in the northern segment while it is convex in the southern oceanward part toward Taiwan. The inflection zone is located around the Tokara channel. The concept of Gaussian curvature of a curved surface suggests that the along-arc variation of the geometric configuration of a subducted slab is related to the shape of the trench. This is in order to accommodate the lateral membrane deformation of the slab as the oceanic lithosphere subducts from a spherical shell to the geometry delineated by the Wadati-Benioff zone. The membrane deformation regime of the subducted Ryukyu slab and its relation with the trench geometry was examined by assuming that the subduction be modelled by the flow field of a thin viscous sheet. A projection operator was utilized to compute the membrane strain-rate tensor of an arbitrary non-Euclidean surface. Numerical experiments indicated that the northern segment of the slab was dominated by lateral compression and down-dip extension and the southern part by lateral extension and down-dip compression. This transition is sharply located near the Tokara channel. These patterns were compatible with what had been observed from studies of focal mechanisms, suggesting that the strain segmentation might be controlled, at least in part, by the lateral membrane deformation within the slab due to the trench shape in this subduction zone. The slab geometry was predicted by minimizing the integrated total dissipation power; this revealed distinct features that were consistent with observations. This implies that the slab geometry may also be affected by the membrane deformation in a systematic fashion.  相似文献   

聚四氟乙烯平板型气态膜回收淡盐水中氯气          下载免费PDF全文

于伯杉 《盐湖研究》1993,1(4):75-79

本文以离子膜电解氯化钾制取碳酸钾工艺产生的淡盐水为原料,系统地研究了聚四氟乙烯平板型气态膜回收氯过程中膜性能和次氯酸钠水溶液的制备。初步研究表明,次氯酸钠含量大于100g/L,氢氧化钠有效利用率为90％;聚四氟乙烯膜有传质快、对离子截留性能好、使用寿命长等优点,在工业上有较好的应用前景。  相似文献   

Reply to Sandgren and Smol: further discussion on chrysophyte cyst taxonomy     

Heikki Simola 《Journal of Paleolimnology》1993,9(1):63-68

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SEM Observation of the Wing Membrane of Beipiaopterus chenianus (Pterosauria)     

KOBAYASHI Yoshitsugu 《《地质学报》英文版》2005,79(6):766-769

The cross-section and surface structures of wing membranes from the ctenochasmatid pterosaur Beipiaopterus chenianus were observed through a scanning electron microscope （SEM）. The results show that the wing membrane contains a high density of blood vessels, implying strong thermoregulatory function, similar to that of a bat wing membrane. This is the first comparison of the microstmctures of pterosaur wing membranes with those of the modem bat. It is inferred that a bat-like physiology exists, at least in relatively small pterosaurs suggesting that these pterosaurs were warm-blooded, active fliers.  相似文献   

块状地质体的多面体表示及交互编辑   总被引：2，自引：0，他引：2  

陈少强  李琦 《地球学报》2005,26(2):191-194

针对固体矿产的地质建模问题,中国科技工作者提出了用于人机交互构造块状地质模型的“橡皮膜技术”并在此基础上完成了人机交互计算机辅助勘查系统PandaCAEX。“橡皮膜技术”可以快速地构造出任意形状的块状地质模型,为地质模型的构造提供了极大的方便。但“橡皮膜技术”本身存在着模型表达过于复杂和一些功能上的缺陷。本文针对这些问题提出直接使用多面体模型对块状地质体进行表达,同时给出了模型的交互编辑方法。与“橡皮膜技术”相比,这种技术在保留“橡皮膜技术”优点的同时,使块状地质模型的表达大大简化、功能更加完善。该模型已经成为新的改进系统的核心,证明了模型的实用性。  相似文献   

外源污染物对硬骨鱼甲状腺干扰作用机制的研究进展          下载免费PDF全文

田华  霸婉玉 《海洋通报》2021,(5)

甲状腺激素在鱼类生长发育、变态、生殖、渗透调节以及摄食和营养代谢中发挥着重要作用,外源化合物对硬骨鱼的甲状腺干扰作用会导致发育和孵化延迟、运动性降低。本文首先对鱼类甲状腺激素的中枢调控、合成、转运、代谢和发挥作用的相关过程进行简要介绍,随后从核受体介导途径、非受体介导途径两个方面综述了外源污染物对硬骨鱼甲状腺的干扰作用机制,最后从物种特异性、检测指标、膜受体介导途径三个方面提出了目前研究的不足之处以及解决方法,以期为今后探究外源污染物对鱼类甲状腺系统干扰作用机制的研究提供更多的参考。  相似文献