The relationships between particulate and soluble alkaline phosphatase activities and the concentration of phosphorus dissolved in the seawater of Toulon Bay (NW Mediterranean)

The activities of particulate and soluble phosphatase were analyzed monthly for 1 year in the coastal ecosystems of the NW Mediterranean Sea. The mean contribution of the particulate activity increased from 56% at an MUF-P concentration of 30 μM to 77% at 0.04 μM. This particulate activity was negatively correlated with the DIP, DOP and TDP concentrations when the activities were related to the seawater volume, chlorophyll a or the protein concentration. The TDP correlations were highly significant (p: 0.001). The DOP correlations were significant (p: 0.04) and became highly significant (p: 0.009) at low DIP concentrations (<0.13 μM). The DIP correlations were significant (p: 0.04) only at low DOP concentrations (<0.18 μM). Thus, the effects of seawater DIP and DOP were found to be linked. The soluble activity exhibited distinct phosphatase fractions with high (0.5–29.5 μM) and low (0.02–2 μM) Km values, but none exhibited significant correlations with phosphorus compounds.     

Improved geological mapping using landsat-5 TM data in Weixi area,Yunnan province China

Different image processing algorithms have been evaluated in the context of geological mapping using Landsat TM data. False color composites, the principal component imagery, and IHS decorrelation stretching method for Landsat-5 TM data have been found useful for delineating the regional geological features, mainly to provide the maximum geological information of the studied area. The study testifies that using which image processing yields best results for geological mapping in arid and semiarid regions by preserving morphological and spectral information. Generally, the studied area can be divided into three main geological units: Basaltic intrusive rocks, Metamorphic with varying intensities and Sedimentary rocks.     

聚合物钻井液防塌机理的试验研究

在试验研究的基础上对比了无机聚合物硅酸盐和有机聚合物——聚乙烯醇（PVA）、部分水解聚丙烯酰胺（PHPA）、非水解聚丙烯酰胺（PAM）和聚丙烯酸钾防塌能力的大小；由试验得出吸附成膜速度的快慢和保护膜的致密程度是决定钻井液体系防塌能力的关键因素；钻井液体系的防塌能力是无机聚合物和有机物质协同作用的结果；部分水解聚丙烯酰胺钻井液体系的防塌能力较非水解聚丙烯酰胺钻井液体系的防塌能力强；Na-CMC和PHP的加入可提高吸附膜的致密性及体系的防塌能力。     

The effects of layering and local stresses in composite volcanoes on dyke emplacement and volcanic hazards

Since most volcanic eruptions are fed by dykes, any assessment of volcanic hazards in an area must include an evaluation of the probability of injected dykes either reaching the surface or becoming arrested. Composite volcanoes are normally composed of alternating stiff (high Young's modulus) and soft (low Young's modulus) layers. Numerical models indicate that during unrest periods with magma-chamber inflation, the local stresses in composite volcanoes commonly prevent dyke-fed eruptions: while the stresses in the stiff layers may favour dyke propagation and seismogenic faulting, the local stresses in the soft layer remain seismically quiet and favour dyke arrest. Geodetic and field studies also indicate that most dykes never reach the surface, and that only a small fraction of the magma volume injected from a chamber erupts at the surface. I propose that for a dyke-fed eruption to occur, all the layers along the potential pathway of the dyke must have local stresses that favour magma-driven extension-fracture propagation. Thus, the stress field along the pathway must be homogenised. To cite this article: A. Gudmundsson, C. R. Geoscience 337 (2005).     

无机抗菌材料及应用

无机抗菌材料是一种新近研制并开始获得应用的功能材料。简要介绍银系抗菌剂和氧化钛光触媒系抗菌剂的性质和抗菌机理、方法，并介绍应用这些无机抗菌剂制得的抗菌布料、抗菌塑料、抗菌卫生陶瓷和抗菌活性炭等各种抗菌产品。     

陶瓷基复合材料及其制造工艺

就陶瓷基复合材料的增韧机理、基体和增强增韧纤维的选择、陶瓷基复合材料的制造工艺,尤其是ＣＶＩ工艺作了较为全面的总结和介绍,并提出了陶瓷基复合材料亟待解决的问题和发展方向。     

Distribution and Fluxes of Calcium Carbonatealong the Continental Margin in the Gulf of Biscay

Compositions of major components in suspended matter,collected by centrifugation, in situ pumping andsediment traps, in the Gulf of Biscay during the OMEXproject were determined and compared. The resultsshow a strong and rapid decrease in the concentrationof biogenic fraction in the upper 200 m of the watercolumn which may be attributed to the preferentialremoval of this component due to the production offaecal pellets and to the formation of marine snow. Concurrent decrease with depth of the organic andinorganic carbon contents demonstrate the importanceof the respiration of organic matter and thedissolution of calcium carbonate in the oceanic carboncycling. Lithogenic and carbonate fluxes across thecontinental slope in the Goban Spur area wereevaluated based on sediment trap records. The rate ofproduction of calcium carbonate in the surface waters(100 g CaCO3 m-2y-1), deduced from theprimary production measurements, is much largercompared to the fluxes of this component observed inthe sediment traps (5–21 g CaCO3 m-2y-1)and to its rate of burial (9–31 gCaCO3 m-2y-1). It strongly suggeststhe occurrence of carbonate dissolution, even inwaters oversaturated with respect to the mineral phaseconsidered. This is likely to be associated with therespiration of organic matter within the faecalpellets, or at the surface of biogenic calcite oraragonite     

Citrate-dithionite-bicarbonate extractable phosphorus (CDB-P) pool in the suspended and surface sediments of the tidal flat area in inner Ariake Bay,Japan

CDB-P (phosphorus extractable by the citrate-dithionite-bicarbonate extraction procedure) was used as the indicator of bio-available inorganic P in the suspended and surface sediments in the inner part of Ariake Bay. The CDB-P pool of suspended and surface sediments in the tidal flat area was estimated to be 10 ton and 90 ton, respectively (total of 100 ton), which corresponds to 1.5 times the average dissolved inorganic phosphorus standing stock. During the summer periods of hypoxia, the CDB-P concentration in the surface sediments decreased with the decline of Eh, losing 43–47% of the CDB-P observed in April. These results suggest that the phosphorus dynamics have been affected by the decrease of resuspended sediment concentrations brought about by the reduction of the tidal currents and phosphate release from the surface sediments during frequently occurring summer hypoxia events.