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自然化合型进化论需要解决的难题 被引量:1
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作者 黎群武 《医学与哲学(A)》 CSSCI 北大核心 2009年第5期18-19,共2页
无生源论认为生命是自然化合而来的。要使这一假设成立,需要解决以下悬而未决的难题:一是由无机物和简单有机物合成生命小分子存在的问题;二是由生命小分子合成生命大分子存在的问题;三是由生命大分子聚集合成原始生命存在的问题;四是... 无生源论认为生命是自然化合而来的。要使这一假设成立,需要解决以下悬而未决的难题:一是由无机物和简单有机物合成生命小分子存在的问题;二是由生命小分子合成生命大分子存在的问题;三是由生命大分子聚集合成原始生命存在的问题;四是由原始生命进化成细胞存在的问题。 展开更多
关键词 无生源论 自然化合 进化 难题
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Calculation of Environmental Capacity of Petroleum Hydrocarbon in Jiaozhou Bay 被引量:1
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作者 李克强 王修林 +4 位作者 邓宁宁 石晓勇 祝陈坚 韩秀荣 胡海燕 《Marine Science Bulletin》 CAS 2004年第1期53-59,共7页
The method has been established to calculate the environmental capacity (ECO), surplus environment capacity (SECO) of water with respect to marine petroleum hydrocarbons associated with oil (PHAOs) and the self-purifi... The method has been established to calculate the environmental capacity (ECO), surplus environment capacity (SECO) of water with respect to marine petroleum hydrocarbons associated with oil (PHAOs) and the self-purification capacity (SPCO) of main self-purification process to PHAOs in the Jiaozhou Bay, China, according to the dynamic model for distribution of marine PHAOs among multiphase environments. The variation of concentration of PHAOs in the Jiaozhou Bay is well simulated by the dynamic model. Based on the model, the ECo, SECo of water with respect to PHAOs in the Jiaozhou Bay were calculated during the last 10 years under the first-class and second-class quality standard requirement, according to SPCO of main self-purification process to PHAOs. The results show that about 200 tons of PHAOs could be discharged into the Jiaozhou Bay for maintaining the first class seawater quality standard, and about 600 tons of PHAOs for the second class seawater quality standard later. 展开更多
关键词 petroleum-hydrocarbon Jiaozhou Bay environmental capacity self-purification capacity kinetic model
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Natural Ageing Tests to Study In-service Different Facade Solutions--ETICS and Premixed One-Coat Rendered Walls
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作者 Luis Silva Ines Flores-Colen +1 位作者 Nuno Vieira Ana Barros Timmons 《Journal of Civil Engineering and Architecture》 2016年第6期667-674,共8页
In situ testing provides accurate characterization of existing degradation mechanisms of materials and building systems which helps reducing the subjectivity of visual inspections especially when ageing under natural ... In situ testing provides accurate characterization of existing degradation mechanisms of materials and building systems which helps reducing the subjectivity of visual inspections especially when ageing under natural ageing conditions is carried out over significant periods of time. In this work, data collected from field experimental campaigns over 10 years after construction using several premixed one-coat rendered walls and over 4 and 6 years after construction in the case of ETICS (external thermal insulation composite systems) are presented and discussed. The influence of hydrophobic agents on the performance of both types of facades in terms of surface condition and water penetration was assessed by visual inspections, Karsten test and capillary tests. Additionally, adhesion tests and subsequent evaluation of porosity were also carried out for premixed one-coat mortars. The results obtained have shown that ageing of the rendering solutions, especially after 5 or 6 years in-service, results from the loss of resistance to liquid water penetration, especially at the surface. Yet, additional mechanisms such as leaching of hydrophobic agents and photochemical degradation are thought to be involved, too. Moreover, the results obtained using the Karsten test proved to be the most reliable method to determine the loss of water penetration resistance and predict the ageing of facade solutions. The information collected and the correlations established can help developing solutions to prevent early ageing and implement appropriate maintenance plans to delay their effect. 展开更多
关键词 Natural ageing tests faqade solutions water resistance hydrophobic agents adhesion.
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Study on the prediction of visible absorption maxima of azobenzene compounds
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作者 刘军娜 陈志荣 袁慎峰 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE EI CAS CSCD 2005年第6期584-589,共6页
The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respecti... The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=?8.1537+6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules’ orbital geometry indicates that their visible ab- sorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital). 展开更多
关键词 Azobenzene compound Nature bond orbital (NBO) Visible absorption maxima
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Laboratory Obtaining of Ferroalloy after Reduction of Oxides from Waste Product and Natural Resource
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作者 Petar Petrov Maksim Marinov Rositsa Paunova 《Journal of Environmental Science and Engineering(B)》 2013年第1期15-19,共5页
The Obrochishte deposit located in the Republic of Bulgaria has considerable reserves of relatively poor carbonate manganese ore. At the same time, in the country there are operative outputs for the production of sulp... The Obrochishte deposit located in the Republic of Bulgaria has considerable reserves of relatively poor carbonate manganese ore. At the same time, in the country there are operative outputs for the production of sulphuric acid where vanadium catalyst is deactivated and discharged, polluting the environment. The utilization of these materials requires their consolidation to proper sizes with regard to the next processing, as the most suitable method for joint consolidation is agglomeration. The present work explores the preliminary calculations for obtaining agglomerate and obtaining an alloy with high and low carbon content, through carbothermic and aluminothermic agglomerate reduction. 展开更多
关键词 Manganese ore vanadium catalyst AGGLOMERATION complex alloy.
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How to Apply Color to the Landscape Design
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作者 Chunyan Yu 《International English Education Research》 2014年第7期20-21,共2页
In nature, garden plants are colorful with obvious seasonal changes. Using plant colors for landscape design, one must first understand the composition and function performance of various colors. Only following the ba... In nature, garden plants are colorful with obvious seasonal changes. Using plant colors for landscape design, one must first understand the composition and function performance of various colors. Only following the basic art principle can we achieve the ideal color combination effect to create all kinds of beautiful landscape. This paper analyzes the color connotation and meaning first, and then elaborates the color applications in landscape design. 展开更多
关键词 LANDSCAPE COLOR CONTRAST harmony.
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Estimation of Some Plant Secondary Products in Urtica dioica L., Viola odorata L. and Melissa officinalis L. Naturally Grown in Hawraman-Kurdistan Region of Iraq
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作者 Abdulsalam Abdulrahman Rasool Kadhm Abdullah Muhammad 《Journal of Agricultural Science and Technology(B)》 2013年第7期480-486,共7页
The plant aerial parts of three species, Urtica dioica L., Viola odorata L. and Melissa officinalis L. were collected at randomly-different locations, according to altitudes in May 2010. The aerial parts of Urtica wer... The plant aerial parts of three species, Urtica dioica L., Viola odorata L. and Melissa officinalis L. were collected at randomly-different locations, according to altitudes in May 2010. The aerial parts of Urtica were collected within three replications from different locations: Biare 1,090 masl (meters above sea level), Tawile 1,450 masl and Awiser 1,680 masl. The aerial parts of Viola and Melissa were collected randomly within three replications at different locations: Biare 1,090 masl, Degashikhan 1,250 masl and Tawile 1,450 masl. The extracts of the aerial parts of these species were purified by filtrations for several times in preparation for HPLC analyses. The chromatograms of Urtica indicated the presence of five major important alkaloid components (fragrine, benzylisoquinoline, scopoletin, glucoquinone and dotriacotaine) and ten major important phenolic compounds (formic acid, tannin, chlorogenic acid, caffeoylmalic acid, anthocyanine, quercetin, zeaxanthin, luetin epoxide, coumarine and vanillin). All the concentrations of alkaloid and phenolic compounds were increased significantly due to higher altitudes, except that of alkaloid dotriacotaine. The chromatograms of Viola indicated the presence of four major important alkaloid components (violine, isoquinoline, cycloviolacin and luteolin-3-glucoronide) and ten major important phenolic compounds (formic acid, tannin, chlorogenic acid, caffeoylmalic acid, anthocyanine, quercetin, zeaxanthin, luetin epoxide, coumarine and vanillin). The results of the influence of altitudes showed that the concentrations of all alkaloids and phenolic compounds were increased significantly due to higher altitudes, except that of the alkaloid luteolin-3-glucoronide and the phenolic compounds zeaxanthin and luetin epoxide. The chromatograms of Melissa indicated the presence of five major essential oils (pinene, linalool, citronellol, geraniol and rosmarinic acid). Their quantitative evaluations were influenced by altitudes indicating that the concentrations of all oils were increased significantly due to the higher altitude, except that of the pinene. 展开更多
关键词 Urtica dioica L. Viola odorata L. Melissa officinalis L. ALTITUDES secondary products medicinal plants
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Patterns of reproductive isolation in the Drosophila subquinaria complex: can reinforced premating isolation cascade to other species? 被引量:2
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作者 Devon P. HUMPHREYS Howard D. RUNDLE Kelly A. DYER 《Current Zoology》 SCIE CAS CSCD 2016年第2期183-191,共9页
The reinforcement of premating barriers due to reduced hybrid fitness in sympatry may cause secondary sexual isolation within a species as a by-product. Consistent with this, in the fly Drosophila subquinaria, females... The reinforcement of premating barriers due to reduced hybrid fitness in sympatry may cause secondary sexual isolation within a species as a by-product. Consistent with this, in the fly Drosophila subquinaria, females that are sympatric with D. recens mate at very low rates not only with D. recens, but also with conspecific D. subquinaria males from allopatry. Here, we ask if these effects of re- inforcement cascade more broadly to affect sexual isolation with other closely related species. We assay reproductive isolation of these species with D. transversa and find that choosy D. subquinaria females from the region sympatric with D. recens discriminate strongly against male D. transversa, whereas D. subquinaria from the allopatric region do not. This increased sexual isolation cannot be explained by natural selection to avoid mating with this species, as they are allopatric in geographic range and we do not identify any intrinsic postzygotic isolation between D. subquinaria and D. transversa. Variation in epicuticular hydrocarbons, which are used as mating signals in D. subquinaria, follow patterns of premating isolation: D. transversa and allopatric D. subquinaria are most similar to each other and differ from sympatric D. subquinaria, and those of D. recens are distinct from the other two species. We suggest that the secondary effects of reinforcement may cascade to strengthen reproductive isolation with other species that were not a target of selection. These effects may enhance the divergence that occurs in allopatry to help explain why some species are already sexually isolated upon secondary contact. 展开更多
关键词 epicuticular hydrocarbons hybrid sterility mate choice REINFORCEMENT SPECIATION WOLBACHIA
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