中亚热带优势灌木根系对土壤抗剪切力的影响

在浙江南部的山体滑坡、泥石流易发区,对中亚热带常绿阔叶林中3种优势灌木植物(檵木、麂角杜鹃和香港黄檀)根系进行野外和室内剪切测试,探讨了灌木植物根系增强土壤抗剪切强度的作用。结果表明:须根相对丰富的植物能明显提高表层土壤的抗剪强度;根系抗拉力和抗剪力均与根径呈幂函数正相关关系;檵木和麂角杜鹃根系抗拉强度与根径呈幂函数负相关关系,而香港黄檀根系抗拉强度与根径无明显相关性;细根或比粗根更有利于土壤加固和抗剪强度的提高。     

根系含量对岩质边坡表层抗冲刷性的影响

为研究植被根系含量对岩质边坡表层抗冲刷性的影响,通过根系含量与粘聚力增加值关系建立了根系密度与土壤抗剪强度的关系式,推导了根系分布密度的土壤临界切应力,进而推算客土层滑动面范围内的单位体积含根量。最后,选取实例研究植被根系含量对岩质边坡表层抗冲刷性的影响,为边坡选择最适合的绿化草种和单位面积的播种数量提供有效依据。     

生态护坡中桉树根系的固土效果试验研究

目的研究生态护坡中植物根系在土体中的加固方法和原理。方法通过土样的含水量测定试验、直剪试验和现场抗拉试验,建立了桉树林地土壤含水量与抗剪强度指标以及根系直径与根系最大抗拉强度和最大抗拉力之间的关系。结果土体抗剪强度参数值均随着土壤含水量的增加而减小,根系最大抗拉强度随着根系直径的增加呈现增加的趋势,最大抗拉力随着根系直径的增加呈现出减小的趋势,而植被根系的最大抗拉拔力与根土之间的静摩擦系数、根的直径、埋深和根周围土体的重度有关。结论根系最大抗拉强度与根系直径两者之间符合指数函数关系,最大抗拉力与根系直径两者之间符合正相关关系,植被根系越粗埋深越大,周围土体越密实则其最大抗拉力就越大。     

树根的生长发育分析

1．根和根系的类型及作用 1．1根的类型 树木的根系是由种子的胚根发育而来的，当种子萌芽时、胚根首先突破种皮向地生长，形成主根。主根由胚根直接发育而来。主根经过生长，逐渐产生侧根，称为次生根。侧根上生长着较细的根城为须根。由胚根发育而来的根叫定根，胚根一定会发育成根系。与此相对应的是从茎、枝形成层和维管束组织产生出来的根，称为不定根。实生的树木可以有定根和不定根，营养繁殖的树木只有不定根。定根和不定根均有同样的构造和生理功能，同样可以产生须根。在树木生长过程中，须根上长出许多幼嫩的小根，但粗度略大干须根，这就是生长根。     

控根栽培下桂花根系的动态生长与垂直分布特征

在控根栽培模式下,采用土钻法对6年生桂花嫁接苗的根系分布和季节动态进行研究。结果表明:一年中,随着时间的变化,桂花根系长度、根系体积、根长密度都呈增长趋势;须根萌发明显,细根增多,根系分布层上移,主要集中在0～10 cm土壤深度,说明控根容器对桂花根系构型产生一定影响。     

海堤林带树木根系对堤防安全影响探讨

通过对苏北现有海堤防护林造林树种的根系，土壤抗冲，抗蚀及渗透性能进行了认真调查和试验测定工作。本文认为：（１）树木根系有较强的网络土壤功能，能大大提高土壤的抗冲，抗蚀性能，其抗冲，抗蚀指数随根量（尤其是细根数量）的增加而增加。（２）海堤树木根系分布有其独特性，水平根系主要由２－３根较粗侧根组成，并沿海堤走向水平伸展，而垂直伸向海堤的侧根较少。垂直根系分布深度视树种，年龄而异，一般在０．６－１．０ｍ     

黄土区直根系作物地土壤分离生长季动态*

目的为黄土高原土壤侵蚀控制提供科学依据。方法运用变坡试验水槽的实验方法,研究了黄土高原地区典型直根系作物大豆和马铃薯在生长季土壤分离过程的季节变化及潜在影响因素。结果 1在作物生长季,直根系作物大豆地和马铃薯地的土壤分离能力具有明显的季节变化(P0.05),并表现出了相似的季节变化模式;2两种作物地土壤分离能力的季节变化主要受到农事活动、土壤硬化、水稳性团聚体和作物根系生长的影响;3两种作物地土壤分离能力的季节变化可以用水流剪切力、土壤粘结力和作物根系密度很好地模拟(R20.64,NSE0.63)。结论黄土区直根系作物地土壤分离过程具有明显季节变化,该变化主要是由农事活动、土壤粘结力和作物根系密度季节变化影响所致。     

三峡库区嘉陵江岸生优势须根系植物根系对土壤抗冲性的增强效应研究

对三峡库区嘉陵江江岸植被的12种优势须根系草本植物进行了研究,考察了各种植物根系对土壤抗冲性的增强作用,并利用WinRHIZO根系分析系统对各种植物根系的形态学指标进行了分析.结果表明:12种须根系植物对土壤抗冲性均有显著的增强效应,不同植物种对于土壤抗冲性增强的贡献大小不同,贡献大小与根系特征密切相关.建立了各种植物对土壤抗冲性增强值与根系生物量及形态学指标之间的回归关系,推荐了几种适用于江岸稳定和水土保持控制的具有推广价值的高土壤固持能力的植物物种.     

不同根系方位及径级下草本植物根土复合体抗剪强度试验研究

本文选取中国过渡带北侧山地土壤与莎草科植物(针薹草)开展植物根-土复合体抗剪强度试验研究,分析不同根系方位及径级下草本植物根-土复合体抗剪强度增强作用以及抗剪强度指标变化规律。试验结果表明：相同法向应力下, 根-土复合体试样的抗剪强度随着方位角度的增大而逐渐增加,且当方位角θ=90°时即垂直布根时,根-土复合体试样的抗剪强度达到最大;根-土复合体试样的抗剪强度随着径级的增加而逐渐增大;随着根系方位角的增加,根-土复合体试样的粘聚力逐渐增大;相同方位角时,随着根系径级的增加,根-土复合体试样的粘聚力亦逐渐增大;根-土复合体内摩擦角与根系径级和方位影响不大且规律性不明显。     

金沙江干热河谷乡土草本植物根系固土能力原位测定

研究采用野外原位剪切试验的方法,对金沙江干热河谷分布较广的扭黄茅(Heteropogon contortus)、莎草(Eulaliopsis binata)、芸香草(Cymbopogon distans)、旱茅(Schizachyrium delavayi)等4种乡土草本植物的根系固土能力进行了研究.结果表明:① 草本植物根系能提高土壤的抗剪强度,起到固土作用.在受试的4种草本植物中旱茅根系提高土壤的抗剪能力最强达72.5%,扭黄茅最低为2.8%;② 在特殊情况下,根系会降低土壤的抗剪强度,起到疏松土壤的作用.在研究中,扭黄茅根系第1样方出现了抗剪强度低于裸土样方的情况;③ 植物根系在提高土壤抗剪强度的同时,也提高了土壤的破坏位移.在受试的4种草本植物中,破坏位移最大是莎草、最小是芸香草,分别比裸土样方提高了109.4%、32.7%,草本植物根系提高土壤剪切破坏位移的幅度比提高抗剪强度的幅度大;④ 在受试的4种草本植物中,旱茅固土能力最强,又是优良的牧草,在金沙江干热河谷生态恢复、边坡防护、植物篱等生态工程中可作为优先选用的植物.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to