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1.
珍稀植物银鹊树木材解剖学观察Ⅰ   总被引:3,自引:0,他引:3  
通过对银鹊树(Tapisicia sinensis Oliv.)的木材解剖学研究,结果表明其木材解剖学特点的结构类型为非叠生型,导管类型有螺纹、梯纹、孔纹,穿孔板类型为梯状穿孔板,射线呈单列异型射线、多列异型射线。  相似文献   

2.
Rhododendrondanricum是Ericaceae,Rhododendron植物,对其木材进行解剖发现其为散孔材,射线为异Ⅱ型,在离析材料可见维管管胞和纤维管胞,导管穿孔为梯状穿孔板。  相似文献   

3.
同种植物木质部的演化结构研究   总被引:1,自引:0,他引:1  
利用光学显微技术,对刺五加Eleutherococcus senticosus Maxim。根和茎的次生木质部进行解剖学研究,发现根的导管长度、导管口径、纤维长度、穿孔板形态及射线等特征均比茎的演化水平高,因此,验证了Bailey的植物演化理论,符合根与茎在演化上的没步理论,即:根在植物系统演系后天的产物,同时以刺五加为代表植物,充分研究了次生木质部的演化问题。  相似文献   

4.
用离析法观察比较了4种木贼属(Equisetum)植物根状茎和气生茎中木质部的管状分子类型,结果发现:这4个种植物的初生木质部中均具导管;在节与节间部的导管分子的形态存在显著差异:节部的导管分子主要是梯纹导管,粗短,常多个聚集成团束(fascicle),末端壁几乎与侧壁平行,穿孔板为梯状、网状和单穿孔板,同时,还发现有网状侧壁穿孔板;节间部的导管分子主要是环纹或螺纹导管,细长,末端壁倾斜或平齐,具梯状、网状和单穿孔板.  相似文献   

5.
用光镜和扫描电镜比较了桃金娘科(Myrtaceae)9属21种木材的解剖结构。结果表明:多数种木材生长轮不明显,几乎都为散孔材,木材分子非叠生,导管分子单穿孔板,管间纹孔具附物,胞间道和管状分子壁螺纹加厚壁缺如,少数种有分膈纤维。2亚科间木材结构有明显差异,桃金娘亚科(Myrtoideae)木材结构较细籽亚科(Lep-tospermoideae)原始。  相似文献   

6.
中国产金缕梅科木材的比较解剖   总被引:3,自引:1,他引:2  
本文根据金缕梅科4个亚科9属10种木材的比较解剖,探讨了金缕梅科的系统发育趋势,并考虑到枫香亚科的木材解剖学、形态学及花粉类型等特征,认为须将枫香亚科从金缕梅科中分出,作为一个独立的科——阿丁枫科.  相似文献   

7.
白蜡条木材解剖性质及其变异的研究   总被引:1,自引:0,他引:1  
通过建立标准地,选择标准木进行树干解析,以及白蜡条木材离析试验,借助电子显微镜和计算机显微图像分析系统,应用定量解剖学方法,从微观角度对白蜡条木材解剖性质及其径向和纵向的变异规律进行了测定和分析。结果表明:白蜡条木材属于环孔材,早材管孔为圆形、椭圆形,轴向薄壁组织量较多,木射线纺锤形、多为同型木射线;白蜡条纤维长度、宽度、胞腔直径、壁厚、壁腔比分别为500~1 428 μm、10~24 μm、7~20 μm、1.4~4.6 μm、0.25~0.58。不同年轮间和树高间,纤维长度、宽度、壁厚、长宽比和壁腔比具有变异性。  相似文献   

8.
榉树木材的发育解剖学研究   总被引:4,自引:0,他引:4  
应用多种制片方法对榉树木材的发育解剖学进行了研究。结果表明:榉树木材为环孔材,年轮明显;早材部分管孔由1~2列导管分子呈环状排列,而晚材部分则由多个螺纹维管管胞和小导管分子组成管孔团,木纤维径向整齐排列,其含量在边材部分较少,而在心材部分较多,这表明榉树在不同生长期形成层分化的各种类型细胞的比例不同;木射线异形多列,由横卧细胞构成主体,而由方形细胞或直立细胞构成射线的边缘部分,形成多列射线的单列尾端;轴向薄壁细胞傍管型环管状。小导管分子和维管管胞具螺纹加厚,导管在心材中为侵填体填充而增加了木材的耐腐性。  相似文献   

9.
为解决微穿孔板消声结构声学仿真计算过程中,微孔给有限元网格划分带来的困难,采用两种不同的简化方法模拟微穿孔板.其一将经典微穿孔板吸声结构理论与传递导纳法相结合,通过在穿孔板内外表面定义一组传递导纳系数表示微穿孔板;其二则计及板材料性能对吸声特性的影响,将微穿孔板转化为等价的多孔材料模型.分别运用这两种微穿孔板简化仿真方法对某高频双层串联微穿孔板消声器的传声损失进行仿真计算,并与阻抗管实验测试结果进行对比.结果表明,两种微穿孔板简化仿真方法均适用于双层微穿孔结构,且能准确有效地预测其声学性能.   相似文献   

10.
提出一个在双层板内插入微穿孔板的隔音结构,微穿孔板与双层板平行,把双层板间的腔体一分为二.对结构建立全耦合的数值模型,微穿孔板与双层板均为有限大板,考虑边界条件,计算得到结构的声传播损失.通过实验对所建立的全耦合数值模型进行验证,计算结果与实验结果符合较好.对微穿孔板的位置、穿孔率、板厚以及微孔孔径进行数值计算研究.计算结果表明:相对传统的双层板或者无微穿孔板的三层板结构,内插了微穿孔板的双层板结构在低频的声传播损失效率有所提高;通过适当的微穿孔板参数设置,该结构可以在低频达到较好的隔声效果.  相似文献   

11.
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   

12.
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   

13.
何延凌 《科技信息》2008,(4):258-258
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
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   

18.
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。  相似文献   

19.
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   

20.
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