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431.
基于B样条小波变换的矢量地图数据压缩及边界处理 总被引:1,自引:0,他引:1
在离散小波变换的快速Mallat算法基础上,根据小波滤波器的特点,提出了一种基于B样条小波变换的矢量数据压缩的边界处理的方法,该方法经袂现可以保证压缩后的数据能如实的反映原数据的特性和规律性。 相似文献
432.
20 0 0年 1月 1 9日至 2 7日在 70°3 0′E- 75°3 0′E,6 2°S以南的南极普里兹湾近岸陆架区的陆隆向深海区设三条纵断面进行浮游生物现存量、真光层深度和光合作用速率的现场观测。并在冰间湖站 - 1 2进行连续昼夜观测。结果表明 ,观测海区叶绿素 a浓度高值位于近岸海湾、冰间湖和测区中部的陆坡区 ;陆坡中部站 - 6和 - 8,0 - 5 0 m的浅水层为叶绿素 a高值区 (2 .1 6- 5 .0 8μg/dm3 )。各测站平均叶绿素 a浓度 2 5 m次表层 (1 .49± 1 .6 1 μg/dm3 )高于表层 (1 .1 4±1 .1 9μg/dm3 ) ,5 0 m以下更深层的浓度随深度的增加而降低 ,2 0 0 m层叶绿素 a浓度仅 0 .0 3±0 .0 2μg/dm3 。昼夜观测结果表明表层叶绿素 a浓度在南极夏季的午后出现最大值 ,晨间出现最小值 ;2 5 m以浅水层的叶绿素 a浓度明显高于深层水 ,与封冰消融冰藻的释放有关。测区真光层潜在初级生产力为 0 .76 - 1 2 .5 9mg C/(m3· h) ,平均值为 4.0 1± 4.0 7mg C/(m3· h) ;海湾和陆架区现场生产力均超过 1 .5 g C/(m2 · d) ,陆坡、深海区约 0 .5 g C/(m2 · d)。高生产力位于高生物量的近岸海湾、陆架冰间湖区。光合作用同化数在 0 .88- 3 .1 0 mg C/(mg Chla· h)。表层叶绿素a浓度与海水中溶解氧浓度呈紧密相关 (Y=0 .0 5 9X 相似文献
433.
The presence of partially oxidized algal organic matter in oil-prone marine source rocks, is the rule rather than the exception. Partially oxidized, algal kerogen can still act as a significant source of liquid hydrocarbons. However, the corresponding peak of C12 + hydrocarbon generation is shifted to a considerably lower maturity level compared with that of the classical Type II kerogen. The extent of primary alteration-oxidation of marine algal kerogen is monitored by means of solid state microfluorescence spectroscopy. A new parameter, the Primary Alteration Factor (PAF) is established, and the relationships between PAF and H/C, O/C, HI, TOC and between PAF and %0δ13C are determined. The present data show large variations in the bulk chemistry of immature marine algal kerogens, and reveal evidence for gradational dehydrogenation/oxidation of the source organic matter. This contrasts with the recently proposed mechanism for kerogen formation. SEM analysis reveals a relationship between the physical breakdown of algal organic matter and the formation of liptodetrinite. FTIR analysis shows that the incorporation of primary oxygen in the kerogen macromolecules is not in the form of carbonyl or carboxyl functionalities. The presence of highly unreactive, stable oxygen, associated with aromatic structures in partially oxidized algal kerogen, is suggested by resistance of the kerogen to graphitization. The FTIR data also suggest the presence of aryl ether oxygen. The present findings raise fundamental questions regarding the mechanisms of kerogen cracking and kerogen formation, and have important implications for petroleum exploration. 相似文献
434.
原生晕法在长期大量的勘探实践中,已被证明是一种有效推测隐伏矿体,进行找矿预测的地球化学勘探方法.在永新金矿床的勘查基础上,通过采集永新金矿区内见矿效果最好的180号勘探线上的4个钻孔的岩石样品,开展了钻孔原生晕的分析.确定了该矿床前缘晕元素组合为As-Sb-Hg,近矿晕元素组合为Au-Ag-Cu-Pb-Zn,尾矿元素组合为W-Mo-Bi-Co-Ni-Cd.与前人总结的金矿经典分带模型相比,前缘晕出现了尾晕元素,同时尾晕序列中也有前缘晕的元素出现,显示了"反分带"的特征,说明在矿体的头部和尾部均有盲矿存在,而依据矿体发育形态来看,矿体头部继续往南东的盲矿已被剥蚀,而矿体尾部往北西方向是下一步勘查的重点. 相似文献
435.
康定黄金坪金矿床原生晕分带特征及找矿意义 总被引:1,自引:0,他引:1
黄金坪金矿床以自然金(银金矿)—多金属硫化物—碲金银系列矿物—碲化物以及石英、黄铁矿等矿物组合为特征;典型元素组合为Au(Ag)-Te-Cu-Pb-Zn-Ba-As。本文应用数理统计方法研究Ⅰ号矿体的原生晕及其分带特征,结果表明侧向分带(矿体向围岩)趋势As-Zn-Pb-Au-Ag-Te-Cu-Ba,垂向分带(由上至下)为Pb-Ag-Au-Zn-As-Te-Cu-Ba。该分带模式对于深部矿化预测与其它矿化带的远景评价具有现实意义。 相似文献
436.
In remote marine aerosol samples collected from the North Pacific ocean, Enewetak Atoll, American Samoa, and New Zealand, series of mid-chain ketocarboxylic acids in the range of C6-C18 were detected. All the positional isomers, except for the 2-oxo and 3-oxo species, were detected for major ketoacid families (e.g. C9, C11 and C13). Higher ketoacid concentrations (up to 19 ng/m3) were obtained in the northern North Pacific aerosol samples, which generally showed an odd carbon-numbered predominance with 5-oxoundecanoic acid being the major species. By contrast, lower concentrations were obtained in the lower-latitude or subtropical aerosol samples, where even carbon-numbered ketoacids were relatively abundant.The distribution patterns of the odd carbon-numbered ketoacids could not be explained by the primary emissions from source materials including terrestrial higher plants, soil particles, and ocean surfaces. We consider that the isomeric ketocarboxylic acids are produced in the atmosphere by the photochemical oxidation of semi-volatile monocarboxylic acids, which are counterparts of the oxidative degradation of unsaturated fatty acids emitted from seawater surfaces. Atmospheric production of the ketoacids is seemingly enhanced in the northern North Pacific, probably due to an enhanced primary productivity. 相似文献
437.
438.
439.
台风是影响东海最严重的自然灾害之一。本文在现场观测基础上,结合遥感与模型数据,研究了连续两个台风过境对东海北部水环境及初级生产力的影响。研究结果表明:连续两个台风过境情况下,虽然前面台风有助于后续台风对海洋上层进行垂直混合作用,但它对后续台风过后海洋表层温度(SST)的降低以及初级生产力的增加却起到了削弱作用;除了加强垂向混合过程,台风也可以改变海洋上层的平流输运过程,受此影响,部分海区上层温度、盐度以及叶绿素在台风后重新分布;台风对海区次表层叶绿素浓度的改变程度明显高于表层,某些站位次表层叶绿素最大值(SCM)在台风刚过后被破坏,一段时间后SCM又重新出现,而且层内叶绿素浓度远高于台风前水平。 相似文献
440.
Nearshore marine environments are influenced by an array of variables that can either be land-derived or of marine origin, and nearshore phytoplankton communities may differ in their taxonomic composition and biomass in response to such variables. The KwaZulu-Natal Bight (hereafter referred to as ‘the bight’) is an oligo-mesotrophic, nearshore oceanic environment, that is influenced by both terrestrial run-off and upwelling. A microphytoplankton survey of the bight conducted over several stations and depths and two seasons was conducted in order to ascertain species composition, abundance and biomass. Microphytoplankton abundance was generally low (a maximum of 180 000 cells l–1 was recorded) but differed considerably between sites and seasons. A total of 99 taxa of mainly Bacillariophyceae and some Dinophyceae, Prymnesiophyceae and Cyanophyceae were identified in the present study. In the central bight, higher abundance and biomass were measured in February (wet season), which may be a possible consequence of terrestrial nutrient inputs. In the northern and southern bight we measured higher abundance and biomass in August (dry season). Upwelling was not detected during the study, but an influence of terrestrial nutrient sources was detected at the coastal stations. Turbid conditions were specific to the site near the Thukela River mouth and possibly influenced abundance, biomass and species composition at this site. Historic data on microphytoplankton composition are scarce, but comparisons with surveys from the 1960s reveal that around 60% of the common diatoms recorded then also occurred in the present study. Small taxa [20–200 µm] dominated the microphytoplankton community. Community composition was fairly uniform throughout the bight in both seasons, dominated in general by Chaetoceros species, and on occasion co-dominated by Thalassionema nitzschioides and Dactyliosolen fragilissimus. 相似文献