油橄榄叶中裂环烯醚萜类化合物的研究进展

裂环烯醚萜作为油橄榄叶中的主要成分,具有重要的药用价值及其它实际应用价值．本文对目前国内外油橄榄叶中裂环烯醚萜类化合物的提取分离、化学成分、含量测定及药理作用进行了综述,以期为我国丰富的油橄榄叶资源的开发利用提供借鉴和依据．     

干旱胁迫对三裂叶豚草种子萌发及幼根生长的影响

研究三裂叶豚草种子萌发及幼根生长对干旱胁迫的响应,旨在为科学防控提供依据.以三裂叶豚草种子为材料,用不同质量分数聚乙二醇(PEG)溶液处理,以蒸馏水处理为对照(CK),设置5%、10%、15%、20%、25%5个质量分数梯度代表轻度、中度、重度、极度、极重度干旱,测定日相对发芽率、发芽率、发芽势、发芽指数和活力指数,分析三裂叶豚草种子萌发情况;测定根表面积、投影面积、体积、根长、根尖数及根分叉数,分析幼苗根生长情况;统计种子恢复萌发情况.结果表明：无干旱胁迫的三裂叶豚草种子各萌发指标最高,干旱胁迫强度增加,种子各萌发指标减小,干旱胁迫强度极大时,种子不发芽.与CK相比,轻度干旱胁迫和重度干旱胁迫对三裂叶豚草根长影响不显著,但会促进侧根与不定根生长;中度干旱胁迫会使根长显著变短,并且会抑制侧根与不定根数量的增加.三裂叶豚草种子在PEG质量分数为24.69%的干旱时不发芽.种子在极重度干旱下不萌发,个别种子在极度干旱下不萌发,但当水分充足时,种子依然具有萌发能力.建议在三裂叶豚草种子尚未成熟前,人工拔除植株,或在入侵地种植耐旱强、生长快、根系发达、竞争性强的植物,以控制三裂叶豚草的生长发育...     

利用污水处理厂废弃污泥种植裂叶喜林芋的可行性初步研究

污水处理厂废弃污泥已经成为了一种新的污染源.为了实现其资源化利用、减少处置成本,节约土地资源,研究了高附加值观赏植物裂叶喜林芋在不同浓度污泥中的生长情况.结果表明,添加一定比例的废弃污泥不但适合裂叶喜林芋的种植,还能促进其生长.综合考虑植物生长速度、体内叶绿素、Fe及主要重金属含量后,认为添加50%的污泥较为适合裂叶喜林芋种植.     

上海佘山地区外来入侵物种三裂叶豚草群落的新分布(简报)

2004年,在对上海佘山地区的植被调查中发现外来入侵物种三裂叶豚草（Ambrosia trifida）,当时该物种未形成群落,只为个体的零星分布.但在2006年的追踪调查中,三裂叶豚草已于林缘、路边等形成面积达数十平方米的群落,并完成生长、开花、结实整个生活史,同时有继续蔓延、扩张的趋势,这也是首次在上海发现三裂叶豚草成群落分布.被称作世界性公害植物之一的三裂叶豚草是菊科一年生草本植物,原产于北美加拿大,在世界各国造成了严重的危害,降低农业产量,并威胁到人类的健康.本文通过对三裂叶豚草群落特征的调查,分析其群落组成结构以及生境条件等特征,并对其发展动态变化进行预测,旨在引起相关部门的重视,采取适时措施,对该物种实施监控.     

上海佘山地区外来入侵物种三裂叶豚草群落的新分布

2004年,在对上海佘山地区的植被调查中发现外来入侵物种三裂叶豚草(Ambrosia trifida),当时该物种未形成群落,只为个体的零星分布.但在2006年的追踪调查中,三裂叶豚草已于林缘、路边等形成面积达数十平方米的群落,并完成生长、开花、结实整个生活史,同时有继续蔓延、扩张的趋势,这也是首次在上海发现三裂叶豚草成群落分布.被称作世界性公害植物之一的三裂叶豚草是菊科一年生草本植物,原产于北美加拿大,在世界各国造成了严重的危害,降低农业产量,并威胁到人类的健康.本文通过对三裂叶豚草群落特征的调查,分析其群落组成结构以及生境条件等特征,并对其发展动态变化进行预测,旨在引起相关部门的重视,采取适时措施,对该物种实施监控.     

聚丙烯膜裂纤维自密实混凝土力学参数及其相关关系

通过试验研究了聚丙烯(PP)膜裂纤维体积率和长度对自密实混凝土力学性能(强度、弹性模量和断裂韧性)的影响,结合扫描电镜微观结构分析、Binham流变理论以及断裂力学基本原理分析了纤维对自密实混凝土的工作性和力学性能的影响机理.当PP膜裂纤维的体积率在0.05%—0.15%之间变化,长度在12—15mm时,结果表明,PP膜裂纤维自密实混凝土抗压强度随纤维体积率增加变化不明显,弯拉强度、劈拉强度、弯拉弹性和断裂韧性随纤维体积率增加而逐步增加,抗压弹性模量随纤维体积率增加而减少;PP膜裂纤维自密实混凝土的轴心抗压强度、弯拉强度以及劈拉强度与立方体抗压强度之比分别在0.70—0.73、0.14—0.17和0.08—0.09范围内,轴心抗压强度与立方体抗压强度比值较普通自密实混凝土对比组略有降低,但弯拉强度、劈拉强度与立方体抗压强度之比分别提高17%—42%和14%—29%.当PP膜裂纤维体积率超过0.15%或长度超过15mm,PP膜裂纤维自密实混凝土的强度、弯拉弹性模量及断裂韧性随纤维体积率增加开始出现不同程度的降低.     

合金热裂的凝固力学判据

对当前已提出的有关热裂判据进行了分析，基于实验结果及力学强度理论揭示了传统热裂应变理论的不足，提出了热裂为本质塑性断裂及热裂势的概念，并建立了其凝固力学判据。     

钢纤维间距理论在混凝土轴拉初裂强度计算中的应用

通过对钢纤维混凝土轴拉试验结果的分析 ,研究了钢纤维体积率、混凝土强度等级对钢纤维混凝土轴拉初裂强度的影响。结果表明 :混凝土轴拉初裂强度分别随钢纤维体积率的增大和混凝土强度等级的提高而增大。最后 ,按照断裂力学理论建立了钢纤维混凝土轴拉初裂强度的计算模型 ,提出了钢纤维混凝土轴拉初裂强度的计算公式 ,供修订我国的《钢纤维混凝土设计与施工规程》以及工程设计与施工参考     

整体加筋翼梁结构止裂性能研究

利用ANSYS软件,研究了整体加筋翼梁结构止裂筋位置和截面不同时的应力强度因子和裂纹扩展特性,为了便于比较,并对无止裂筋梁进行了分析。给出了不同止裂筋位置和截面宽厚比下的应力强度因子曲线,分析了止裂筋断裂后对整体加筋翼梁的影响。最后,在给定止裂筋重量条件下讨论了最优止裂性能筋条的宽厚比。     

入侵植物三裂叶蟛蜞菊叶片叶绿素荧光对温度的响应

选取入侵植物三裂叶蟛蜞菊（Wedelia trilobata）及其本地近缘种蟛蜞菊（Wedelia chinensis）为实验材料,以叶绿素荧光影像仪研究整株植物在零上低温（10℃）和室温（25℃）条件下,强光（1700μmo1·m^-2·s^-1）诱导叶片的叶绿素荧光的特性,探讨入侵种三裂叶蟛蜞菊对强光及温度的响应特性和生态适应性．结果表明,室温强光处理5h后三裂叶蟛蜞菊PSⅡ最大光能转化效率（■／R）、PSⅡ实际光化学量子产量（趾埘）、表观光合电子传递速率（ETR）的下降幅度均显著小于本地种蟛蜞菊,而在低温强光处理5h后三裂叶蟛蜞菊的Fv／Fm、Yield、ETR降低幅度显著高于本地种蟛蜞菊．研究结果初步表明,三裂叶蟛蜞菊对室温强光适应性强,而对低温强光则较敏感．这一结果暗示外来入侵种三裂叶蟛蜞菊可能较适应我国南方热带亚热带地区的高温强光气候,而向北方地区进一步扩散有可能受到低温等环境因子的限制．     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the