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含铍含氟硫化铋精矿氯化浸出液中铋、铍、铁物种研究 被引量:2
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作者 郑国渠 唐谟堂 赵天从 《中南工业大学学报》 CSCD 北大核心 1997年第6期543-546,共4页
柿竹园含铍含氟铋精矿成分十分复杂,其氯化浸出液中铋、铍、铁等分别与配位体Cl-,F-,SO2-4形成配合物,物种多达40余种.因此,弄清这些物种的分配和行为,对于该精矿的冶金过程机理及工艺研究都具有重要意义.本文根据... 柿竹园含铍含氟铋精矿成分十分复杂,其氯化浸出液中铋、铍、铁等分别与配位体Cl-,F-,SO2-4形成配合物,物种多达40余种.因此,弄清这些物种的分配和行为,对于该精矿的冶金过程机理及工艺研究都具有重要意义.本文根据同时平衡原理和电中性原理,建立铋、铍、铁及氯浓度平衡和电荷平衡方程,然后用电子计算机联解,求得了各物种分配,并从理论上分析了几种主要元素在干馏过程中的行为,用以指导干馏工艺研究,实验结果与分析结果彼此符合较好.从而使Bi-Be,Bi-Fe分离工艺难题得以解决. 展开更多
关键词 氯化浸出 物种分配 干馏
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Fish community diversity in the middle continental shelf of the East China Sea 被引量:4
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作者 单秀娟 金显仕 +1 位作者 周志鹏 戴芳群 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第6期1199-1208,共10页
The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities (e.g., pollution and overfishing). Thus, the restoration and protection... The status of fishery stocks in the coastal waters of China is far from ideal, mainly due to climate change and the impacts of human activities (e.g., pollution and overfishing). Thus, the restoration and protection of fishery resources have become critical and complex. The stability and balanced structure of the fish community is a basic foundation for the protection of fishery resources. Based on data collected from bottom trawls by the R/V Beidou in continental shelf of the East China Sea in November 2006 and February 2007, changes in the composition and diversity of fish species and functional groups were analyzed. The research area was divided into offshore waters and inshore waters by the two-way indicator species analysis (TWIA). The results showed that the dominant species were different between offshore waters and inshore waters and also varied with the survey time. The most abundant family was Sciaenidae and Teraponidae in November 2006, Sciaenidae, Engraulidae and Triglidae were most abundant in February 2007. The species belonged mainly to mobile piscivores (G6), benthivores/piscivores (G4), benthivores (G3) and planktivores (G1), and the dominant species in November 2006 were commercial species (e.g. Larimichthys polyactis and Trichiurusjaponicus), but small-sized species were dominant in February 2007 (e.g., Harpadon nehereus, Benthosema pterotum, Champsodon capensis, and Acropoma japonieum). The species diversity showed a similar trend as the functional group diversity. Stations with higher diversity were mainly distributed in inshore waters in February 2007, whereas higher diversity was found in offshore waters in November 2006. The highest biomass and species number were found in G6 group, followed by the G4, G5 and GI groups. The distribution of the number of individuals of each functional group showed the opposite trend as that of the biomass distribution. In addition, the size spectra were mainly concentrated around 3-29 cm, and the individual number of fish species gradually decreased with the increase in body size, but the relative biomass showed a moderate fluctuation in each size class. These changes showed that species with faster growth rate and earlier maturity age became dominant in continental shelf of the East China Sea. So the variations in biological characteristics of fish should be fully considered in maintaining sustainable utilization of fishery resource. 展开更多
关键词 fish community DIVERSITY functional group East China Sea
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Mechanisms of species divergence through visual adaptation and sexual selection:Perspectives from a cichlid model system 被引量:3
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作者 Martine E.MAAN Ole SEEHAUSEN 《Current Zoology》 SCIE CAS CSCD 北大核心 2010年第3期285-299,共15页
The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can ... The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process,because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. Whendivergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence.Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selectionagainst intermediate phenotypes that are maladapted to their (sensory) environment. For Lake Victoria cichlids, the visual environmentconstitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigatethe direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours(red and blue) in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extractgeneral principles, and discuss future perspectives [Current Zoology 56 (3): 285-299, 2010]. 展开更多
关键词 CICHLID Sexual selection Species divergence Visual adaptation
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Biomass Allocation Patterns of Alpine Grassland Species and Functional Groups along a Precipitation Gradient on the Northern Tibetan Plateau 被引量:7
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作者 WU Jian-shuang SHEN Zhen-xi +1 位作者 ZHANG Xian-zhou SHI Pei-li 《Journal of Mountain Science》 SCIE CSCD 2013年第6期1097-1108,共12页
Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to ... Variations in the fractions of biomass allocated to functional components are widely considered as plant responses to resource availability for grassland plants. Observations indicated shoots isometrically relates to roots at the community level but allometrically at the species level in Tibetan alpine grasslands. These differences may result from the specific complementarity of functional groups between functional components, such as leaf, root, stem and reproductive organ. To test the component complementary responses to regional moisture variation, we conducted a multi-site transect survey to measure plant individual size and component biomass fractions of common species belonging to the functional groups: forbs, grasses, legumes and sedges on the Northern Tibetan Plateau in peak growing season in 2010. Along the mean annual precipitation (MAP) gradient, we sampled 7o species, in which 2o are in alpine meadows, 20 in alpine steppes, 15 in alpine desert-steppes and 15 in alpine deserts, respectively. Our results showed that the size of alpine plants is small with individual biomass mostly lower than 1.0 g. Plants keep relative conservative component individual responses moisture functional fractions across alpine grasslands at the level. However, the complementary between functional components to variations specifically differ among groups. These results indicate that functional group diversity may be an effective tool for scaling biomass allocation patterns from individual up to community level. Therefore, it is necessary andvaluable to perform intensive and systematic studies on identification and differentiation the influences of compositional changes in functional groups on ecosystem primary services and processes. 展开更多
关键词 Biomass fractions Complementaryresponse Functional components Functional groups Changtang Plateau
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Dry Matter Partitioning, Nodulation and Seed Traits of Medium and Late Maturing Soybean Varieties as Affected by Planting Pattern and Plant Density
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作者 Daniel Markos Udai. R. Pal Elias Uragie 《Journal of Agricultural Science and Technology(B)》 2012年第1期142-150,共9页
An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in ... An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in early and late maturing soybean varieties. Results indicated that Awassa-95 variety produced significantly higher (P 〈 0.05) number of nodules/plant (NDN), nodule dry matter (NDM) and leaf dry matter (LDM at R2 (mid flowering) stage of soybean growth than that of variety Belessa-95). Similarly, variety Awassa-95 (45%) produced significantly higher protein content than variety Belessa-95 (40%). However, variety Belessa-95 accumulated significantly higher (P 〈 0.01) dry matter in straw, grain and total biomass at R7 (physiological maturity) stage of soybean growth than variety Awassa-95. Similarly, oil content of variety Belessa-95 (18.1%) was significantly (P 〈 0.05) higher than that of variety Awassa-95 (15.9%). Equidistant rows produced significantly higher (P 〈 0.05) NDM than either rectangular or paired rows. Moreover, soybean plants grown in both rectangular and equidistant rows produced significantly higher (P 〈 0.01) straw dry matter than those grown in paired rows; but, grain dry matter/plant (GDM) was significantly higher (P 〈 0.01) paired and rectangular rows compared to equidistant rows. Plant density also affected the per plant GDM production as it was significantly higher (P 〈 0.01) in 20 and 30 plants/m2 than higher plant densities (40 and 50 plants/m2). However, dry matter and yield components had strong negative association with protein content. In fact, strong positive correlation (R 〉 0.600) occurred between grain yield and its components with dry matter components at R2 (stem dry matter (SDM), leaf dry matter (LDM) and stem + nodule + leaf dry matter together known as TDM) and straw dry matter at R7 in both varieties. This study depicted that soybean plants that produce higher dry matter components at R2 would probably produce more straw dry matter, greater grain yield components and higher grain yield dry matter at later stages. 展开更多
关键词 Leaf dry matter nodule dry matter protein content oil content plant density planting pattern.
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Above-ground Biomass Allocation in a Planted Forest in a Semi-arid Region of Northern Mongolia
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作者 Sukhbaatar Gerelbaatar Nachin Baatarbileg 《Journal of Agricultural Science and Technology(B)》 2013年第3期216-220,共5页
Investigation of the above-ground biomass allocation patterns on Scots pine plantations is critical for quantifying the productivity and carbon cycle of forest ecosystems. We estimated above-ground biomass and net pri... Investigation of the above-ground biomass allocation patterns on Scots pine plantations is critical for quantifying the productivity and carbon cycle of forest ecosystems. We estimated above-ground biomass and net primary production of a 25-year-old Pinus sylvestris L. (Scots pine) plantation, in a semi-arid region of Mongolia. The above-ground biomass of sample trees was divided into stem wood, stem bark, live branches, dead branches and needles. Total biomass for the stand was only 18.03 Mg ha1, of which 47.6% was found in stem wood, 25.8% in live branches and 14.8% in needles. The growth rate of the Scots pine plantation in the study region was relatively low compared with other regions. In the study area, it was observed that the rate of biomass accumulation in the plantation was very slow; this can be explained by very limited growing conditions and intensive crown closure. The results from this study indicate that it may be necessary to carry out thinning to increase biomass production by reducing competition between trees in the Scotch pine plantation. 展开更多
关键词 Biomass allocation dry biomass Scots pine plantation PRODUCTIVITY forest ecosystems.
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