HONG KONG CELTS.     

C.M.HEANLEY 《地质学报》1928,(Z1)

INTRODUCTION This article has been written as an explanatory note to an exhibit of stone artifacts sent to the meeting of the Society. It is also hoped that for people in South China it will be an introduction to the prehistoric archeology  相似文献   

双星演化与大样本恒星演化     

韩占文  Eggleton P P  Tout C A  Webbink R F 《天文学进展》2001,19(2):242-245

主要介绍了大样本恒星演化所面临的困难，为解决困难所做的努力及对未来的展望。  相似文献   

对美国马萨诸塞州福尔莫斯砂砾岩含水层中铅锌吸附作用地球化学指示剂的研究     

J.A.Coston  C.C.Fuller  J.A.Davis  全仁和 《华东地质学院学报》1993,(2)

本文研究了不同矿物表面对铅、锌吸附作用重要性质。这些矿物(地下物质)是从美国马萨诸塞州福尔莫斯浅层无压含水层中收集的。砂岩主要是石英(95%),还有少量的碱性长石和铁磁矿物。对石英颗粒的统计表明,90%的锌被吸留在250—500μm 的砂岩碎片上.表面分析(SEM—EDAX 和 TOF—SIMS)表明,石英和长石表面被铁、铝覆盖,并高度风化。Pb 和 Zn 的吸附受颗粒大小的影响。被羟胺—HCl 提取的 Fe 和 Al,与在3.5m 长的岩芯内观察到的 Pb 的吸附变化无关.  相似文献   

Effect of solar wind plasma parameters on space weather     

Balveer S.Rathore  Dinesh C.Gupta  Subhash C.Kaushik 《天文和天体物理学研究(英文版)》2015,(1):85-106

Today's challenge for space weather research is to quantitatively predict the dynamics of the magnetosphere from measured solar wind and interplanetary magnetic field(IMF) conditions. Correlative studies between geomagnetic storms(GMSs)and the various interplanetary(IP) field/plasma parameters have been performed to search for the causes of geomagnetic activity and develop models for predicting the occurrence of GMSs, which are important for space weather predictions. We find a possible relation between GMSs and solar wind and IMF parameters in three different situations and also derived the linear relation for all parameters in three situations.On the basis of the present statistical study, we develop an empirical model. With the help of this model, we can predict all categories of GMSs. This model is based on the following fact: the total IMF Btotalcan be used to trigger an alarm for GMSs, when sudden changes in total magnetic field Btotaloccur. This is the first alarm condition for a storm's arrival. It is observed in the present study that the southward Bzcomponent of the IMF is an important factor for describing GMSs. A result of the paper is that the magnitude of Bzis maximum neither during the initial phase(at the instant of the IP shock) nor during the main phase(at the instant of Disturbance storm time(Dst) minimum). It is seen in this study that there is a time delay between the maximum value of southward Bzand the Dst minimum, and this time delay can be used in the prediction of the intensity of a magnetic storm two-three hours before the main phase of a GMS. A linear relation has been derived between the maximum value of the southward component of Bzand the Dst, which is Dst =(-0.06) +(7.65)Bz+ t.Some auxiliary conditions should be fulfilled with this, for example the speed of the solar wind should, on average, be 350 km s-1 to 750 km s-1, plasma β should be low and, most importantly, plasma temperature should be low for intense storms. If the plasma temperature is less than 0.5 × 106 K then the Dst value will be greater than the predicted value of Dst or if temperature is greater than 0.5 × 106 K then the Dst value will be less(some nT).  相似文献   

Tectonomagmatic origin of some volcanic and sub-volcanic rocks from the Lower Benue rift,Nigeria     

Smart C. Obiora  Nirmal S. Charan 《中国地球化学学报》2011,30(4):507-522

Petrological and geochemical studies on some volcanic and sub-volcanic rocks from the Lower Benue rift indicate that they are basalts, basaltic and doleritic sills, trachybasalt and trachyte which generally belong to the alkali basalt series. The alkaline affinity is clearly evident in both their normative and modal mineral compositions, as well as their chemical compositions. The generally high fractionation indices [(La/Yb)N] are 7.06 to 17.65 for the basaltic rocks and 23.59 to 135. 35 for the trachytic rocks, against low values commonly seen in subalkaline (tholeiitic) series, with strong enrichments in the incompatible elements. All this strongly supports their alkaline affinity. The basaltic rocks are generally fine-grained and porphyritic, consisting of phenocrysts of clinopyroxene and olivine in the groundmass of the same minerals together with plagioclase. The clinopyroxene is either diopside or clinoenstatite. The trachyte consists of oligoclase, orthoclase, biotite, quartz and exhibits typical trachytic, flow structure. The basaltic and doleritic sills are commonly altered, with calcite and epidote as common alteration prod-ucts. This alteration, which is reflected in the erratic behaviour of K2O, MnO and P2O5 on Harker variation diagrams, high values of LOI, strong depletions in the more mobile LILE (Rb, K, Ba and Sr) and high Th/Ta ratios, is attributed to the effects of an aqueous fluid phase and crustal contamination. On the whole, the mineralogical, as well as major-, trace-elements and REE data suggest that the rocks are co-genetic and most likely derived from differentiation of an alkali olivine-basalt magma, generating through variable low degrees of partial melting of probably an enriched lithospheric (upper) mantle following an asthenospheric uplift (mantle plume or intumescence) with HIMU signa-tures in a within-plate continental rift tectonic setting. This corroborates earlier results obtained for the intrusive rocks in the region.  相似文献   

Assessment and characterization of heavy metal resistance in Palk Bay sediment bacteria     

Nithya C  Gnanalakshmi B  Pandian SK 《Marine environmental research》2011,71(4):283-294

The present study aimed at characterizing the heavy metal resistance and assessing the resistance pattern to multiple heavy metals (300 mmol L?1) by Palk Bay sediment bacteria. From 46 isolates, 24 isolates showed resistance to more than eight heavy metals. Among the 24 isolates S8-06 (Bacillus arsenicus), S8-10 (Bacillus pumilus), S8-14 (B. arsenicus), S6-01 (Bacillus indicus), S6-04 (Bacillus clausii), SS-06 (Planococcus maritimus) and SS-08 (Staphylococcus pasteuri) exhibited high resistance against arsenic, mercury, cobalt, cadmium, lead and selenium. Plasmid curing confirmed that the heavy metal resistance in S8-10 is chromosomal borne. Upon treatment with the heavy metals, the strain S8-10 showed many morphological and physiological changes as shown by SEM, FTIR and AAS analysis. S8-10 removed 47% of cadmium and 96% of lead from the growth medium. The study suggests that sediment bacteria can be biological indicators of heavy metal contamination.  相似文献   

Sewage pollution in Negril, Jamaica: effects on nutrition and ecology of coral reef macroalgae   总被引：1，自引：0，他引：1  

B. E. LAPOINTE  K. THACKER  C. HANSON  L. GETTEN 《中国海洋湖沼学报》2011,29(4):775-789

Coral reefs in the Negril Marine Park (NMP), Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C:N:P and stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on shallow and deep reefs of the NMP in 1998 showed strong P-limitation and evidence of increasing sewage pollution. In 1999, a sewage collection and treatment project began divertin...  相似文献   

Urban China in transformation: Hybrid economy,juxtaposed space,and new testing ground for geographical enquiries     

George C S LIN 《中国地理科学(英文版)》2011,21(1):1-16

History has brought us into a significant moment when the majority of the human kind has taken up resi-dence in urban settlements. The focus of global urbanization has shifted to the developing world and the center of manufacturing is no longer confined to the Global North. This paper provides a periodical assessment of the current status of China’s urban transformation in the global context of a shifting emphasis of industrialization and urbaniza-tion. China’s phenomenal urban transformation deserves a special attention not only because of its unparalleled scale and speed but also because of its distinct trajectory of growth that does not conform to normal theoretical ex-pectations. The results of assessment revealed an urban economy with remarkable hybridity, a society that is in-creasingly stratified, polarized, and segregated, and a juxtaposed urban space undergoing restless and pervasive transformation. A decentering world should entail a decentering knowledge production. A critical reflection upon the Chinese patterns and processes of urban transformation has identified 4 main issues with great potentials for inno-vative knowledge production, namely: 1) privatization and economic development; 2) state, society, and space; 3) urbanization of capital, labor, and land; and 4) the environment and Chinese political ecology. The paper closes with the remark that a rapidly transforming urban China has presented itself as a fertile and resourceful testing ground for critical and innovative geographic enquiries.  相似文献   

Trophic ecology of the sea urchin Spatangus purpureus elucidated from gonad fatty acids composition analysis     

Barberá C  Fernández-Jover D  López Jiménez JA  González Silvera D  Hinz H  Moranta J 《Marine environmental research》2011,71(4):235-246

Irregular sea urchins such as the spatangoid Spatangus purpureus are important bioturbators that contribute to natural biogenic disturbance and the functioning of biogeochemical cycles in soft sediments. In the coastal waters of the Balearic Islands S. purpureus occurs in soft red algal beds, and can reach high densities. The diet of S. purpureus is unknown and it is particularly difficult to analyze the stomach contents of this group; therefore, we analyzed the fatty acid (FA) composition of the gonads and potential food resources in order to assess the trophic relationships of this species. The FA profiles of the gonads of S. purpureus agree well with the FA composition of the potential trophic resources (algae and sediment) and reveals changes between localities with different available resources. Three polyunsaturated FAs mainly contributes in the composition in the S. purpureus gonads: eicosapentaenoic acid (C20:5n-3) and arachidonic acid (C20:4n-6), both abundant in the macroalgal material, and palmitoleic acid (C16:1n-7), which is characteristic of sediment samples. Trophic markers of bacterial input and carnivorous feeding were significantly more abundant in sea urchins caught on bottoms with less vegetation. The current study demonstrates that the FA content of S. purpureus gonads is a useful marker of diet, as differences in the profiles reflected the variations in detritus composition. The results of this study show that this species has omnivorous feeding behavior; however, viewed in conjunction with available abundance data the results suggest that phytodetritus found within algal beds is an important carbon source for this species.  相似文献   

Organic matter features, degradation and remineralisation at two coastal sites in the Ligurian Sea (NW Mediterranean) differently influenced by anthropogenic forcing     

Misic C  Castellano M  Covazzi Harriague A 《Marine environmental research》2011,72(1-2):67-74

Organic matter (OM) features, degradation and remineralisation were studied in the seawater of a natural coastal site (Marine Protected Area of Portofino) and at an urbanised coastal site (Quarto, Genoa city) of the Ligurian Sea. The accumulation of low trophic value OM and the persistence of phytoplanktonic biomass throughout the year were observed only at the urbanised site. Efficient OM degradation and remineralisation via high-activity (two times higher than at the Portofino site) hydrolytic enzymatic activities (alkaline phosphatase and leucine aminopeptidase) were recorded. This active degradation indicated a generally good resistance of the Quarto system to environmental pressures (coastal inputs and anthropogenic influence). However, the high potential release of recycled inorganic nutrients and the favourable environmental conditions (i.e. higher seawater temperature at the Quarto site and allochthonous inputs), could encourage unpredictable development of the autotrophic fraction, including an already observed dystrophic blooming of toxic microalgae.  相似文献