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椰子是热带地区的主要木本油料作物,具有重要的经济价值。种植椰子投资小,管理粗放,风险少、生产周期长、用途广。当今,不仅椰子的肉、水等食用饮用部分被继续用于生产传统食品,同时,新的食品也在不断的研发生产,且椰子的其他部分还有广泛的用途。最近,还有科学家研究指出椰子汁具有预防心脏病、关节炎、癌症及强健肌肤、滋润止咳之功效。此外,在能源日益短缺的今天,国外早已将椰子油作为一种生物质能源来考虑。因此,在国外,不论是主要椰子生产国还是一些非椰子生产国的研究机构都十分重视对椰子的各种栽培管理技术及产品加工工艺进行研究和开发,从早生、高产、抗性强的椰子选育种、丰产栽培技术、主要病虫害防治技术到椰子产品加工各个领域已开展了广泛的研究,并已取得了令人欣喜的成绩。反观我国,这些年来,虽然椰果年均达两亿多个,但还不到我国食品工业每年对椰子的测算需求量的10%。我国不论是椰子单产、总产还是椰子产品加工方面与世界主要产椰国都存在很大差距,我们应努力提高我国椰子产量、发展我国椰子生产。 相似文献
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研究发现椰一but-甲[Brontispa longissima(Gestro)]各项生育指标与椰子[Cocos nucifera(Linnaeus)]叶片的生长阶段关系密切.统计表明:从幼虫到成虫整个阶段的存活率心叶较成熟叶片高,分别为81%和77%,椰心叶甲完成一个世代在心叶上需要58.54d,在成熟叶片上需要52.92d.叶片生长阶段对虫质量和蛹质量的影响表现为取食心叶较重,且大部分龄期的幼虫质量和蛹质量的差异均显著.椰子心叶和成熟叶片上的成虫的性比分别为n(雌):n(雄)=1.27:1和n(雌):n(雄)=1.17:1,平均产卵量为143.3粒和161.93粒,成虫寿命分别为189.14d和172.36d,椰子心叶和成熟叶上的实验种群趋势指数分别为56.55和56.45. 相似文献
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椰子的生态特性与生产基地的选择 总被引:2,自引:0,他引:2
在深入调查研究的基础上 ,论述了椰子的生态特性与椰子种植地的划分及科学选择 ,并提出了今后发展椰子种植的新布局 ,旨在为大面积种植椰子提供科学依据 . 相似文献
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通过半定量评价法,再次对河南省境内引种的棕榈科近30个属的54种植物的适应能力及它们对土壤生态因子的适应性进行了研究。结果表明,在适应性评价中:优秀的占(1.8%),良好的占(42.4%),较好的占(27.9%),一般的占(18.2%),不良的占(9.7%)。其中,棕榈、蒲葵、大王椰子、袖珍椰子、三药槟榔、红槟榔、假槟榔、董棕及针葵属植物长势良好,保持了原有的观赏价值;鱼尾葵、散尾葵、棕竹、细棕竹、三角椰子、棍棒椰子、狐尾椰子长势较好,但叶面干燥,个别植物叶梢干枯;椰子、槟榔长势较差,白菜棕、香棕、刺棕成活率极低,现存植株观赏效果极差。从上述证据中我们得出了棕榈科植物在河南的适应性条件。 相似文献
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Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
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Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
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There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying. 相似文献
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Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well. 相似文献
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The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation. 相似文献
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QING Hai-ruo 《成都理工大学学报(自然科学版)》2004,31(6)
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction. 相似文献
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In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time. 相似文献
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理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
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As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
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1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1]. 相似文献
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1]. 相似文献