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1.
毛竹材质生成过程中微纤丝角的变化   总被引:1,自引:0,他引:1  
应用X射线衍射法对不同竹龄毛竹材的微纤丝角进行测定分析,探讨毛竹微纤丝角的生长发育规律。结果表明:各竹龄竹材细胞次生壁微纤丝角的径向变异规律呈现波动趋势,平均微纤丝角为9.4°,最大值和最小值分别为12.05°和7.61°,差值小于4.44°,微纤丝角从竹青到竹黄存在显著差异。竹材的微纤丝角从0.5~1.5 a呈增加趋势,而后几年呈下降趋势,到6.5年稍有回升,随后又下降,直至10.5年生竹材微纤丝角值又变得较大,竹龄对微纤丝角影响显著。竹秆的中部和下部平均微纤丝角分别为9.32°、9.39°和9.50°,随竹秆高度增加竹材微纤丝角逐渐减小,差异较显著。  相似文献   

2.
不同竹龄毛竹材表面颜色、润湿性及化学成分分析   总被引:1,自引:0,他引:1  
对不同竹龄毛竹竹材的表面颜色、润湿性及化学成分的变化进行分析。结果表明:随竹龄增加,氙灯照射后毛竹素材表面颜色逐渐变暗加深,颜色变化越来越明显。1年生竹材润湿性最好,2年生竹材润湿性较好,4个月竹材润湿性较弱,4年生竹材润湿性最弱。随竹龄增加,竹材表面半纤维素相对含量增加,木质素相对含量的差异较小;综纤维素含量在4个月至2年生之间逐渐降低,2年生时最低,2年生至10年生之间,变化较小。  相似文献   

3.
毛竹竹冠由秆、枝、叶三部分组成。竹秆分枝部分是竹冠的支柱,竹秆上每一个分枝的节和枝、叶合称为一个枝盘。每一枝上着生主枝、侧枝、小枝,各种枝条按一定规律分布在竹秆四周,构成竹冠的空间支架。每一个叶枝上着生3—5片竹叶,均匀分布在竹冠上形成绿色的叶层,有效地利用太阳光能进行光合作用,生产有机物质。竹冠结构是指竹冠中秆、各种枝条、竹叶的数量及其在各盘枝上的分布。关于毛竹的秆形结构,作者曾作过报道,本文主要论述毛竹竹冠结构的规律性。1979年以来,我们在江苏宜兴县林场,共调查70株标准竹,每株标准竹伐倒后,记录竹龄、胸径、高度、枝下高、总节数、枝下节数、竹冠节数(枝盘数)、竹秆重量以及枝、叶重量等,并按枝盘号调查主枝、侧枝、小枝、叶枝、叶片数等。  相似文献   

4.
不同龄级马尾松对松材线虫病抗性的探讨   总被引:23,自引:6,他引:23  
从松褐天牛(Monochamusalternatus)成虫活体上分离用PDA平板灰葡萄孢(Botrytiscinerea)培养的松村线虫(Bursaphelenchusxylophilus)对不同龄级和不同生长势的马尾松(Pinusmassoniana)的接种试验表明,14年生以下和生长势旺盛的马尾松幼树抗松材线虫病;16年生以上和长势弱的马尾松中龄、成熟和过熟林树对松材线虫病的抗性较弱,并随树龄的增加和长势的减弱抗病能力减弱。对各龄级马尾松的化学内含物萜类和树脂酸的组成分析,长叶烯、α-烯和去氢枞酸的含量随树龄的增加而增加,并与其抗性呈负相关;β-蒎烯、单萜和枞酸型树脂酸的含量随树龄的增加而减少,并与其抗性呈正相关。有相关性的化学内含物加入PDA灰葡萄孢平板培养基培养松材线虫,与接种试验有相同趋势,长叶烯和去氢枞酸加入量的增大有利于线虫繁殖;β-蒎烯、单萜和枞酸型树脂酸则相反,加入量增大(与树内量相近)线虫的繁殖量减少,说明含量高时对线虫的生存和繁殖有抑制作用。  相似文献   

5.
不同刈割期紫花苜蓿产量及营养分析   总被引:1,自引:0,他引:1  
对紫花苜蓿不同刈割期的产量及营养进行了测定。结果表明:不同刈割期紫花苜蓿的产量差异极显著(P〈0.01),第一茬最高为7473.8kg,耐,第三茬3827.9kg/hm^2,第二茬2316.2kg,雠。粗蛋白(CP)含量随刈割时期顺序变化呈下降趋势,第三茬与第一茬、第二茬差异极显著(P〈0.01)。酸性洗绦纤维(ADF)、中性洗涤纤维(NDF)含量随刈割时期顺序变化呈上升趋势,不同刈割期期间差异极显著(P〈0.01)。  相似文献   

6.
不同落羽杉种源木材化学性质的变异   总被引:1,自引:0,他引:1  
对16个落羽杉种源的14年生人工林木材化学性质进行了测定,结果表明:(1)16个落羽杉种源木材纤维素相对结晶度、综纤维素含量、木素含量、NaOH抽出物含量和pH等均存在显著差异;(2)16个落羽杉种源木材纤维素相对结晶度在74.43%~61.52%,总平均值为65.87%,总变异系数为5.27%,树干不同高度处木材纤维素相对结晶度含量存在极显著差异。16个种源木材综纤维素含量、木素含量、NaOH抽出物含量和pH等的变异范围分别为62.64%~71.53%、23.98%~29.53%、3.9%~17.9%和5.32%~5.07%,总变异系数分别为3.9%、6.7%、44.8%、1.53%,NaOH抽出物含量变异系数较高。落羽杉树干不同高度处木材综纤维素含量、木素含量、NaOH抽出物含量和pH差异未达显著水平;(3)16个落羽杉种源整体上综纤维素含量高,NaOH抽出物含量和木素含量低,经过进一步筛选后,部分种源可作为优良的纸浆林造林材料进行推广。  相似文献   

7.
不同竹龄毛竹材纤维饱和点的测定   总被引:1,自引:1,他引:0  
以毛竹为研究对象,采用力学法对不同竹龄毛竹的纤维饱和点计算进行了系统研究。结果表明:通过Boltzmann曲线拟合毛竹材力学性能得到的毛竹纤维饱和点较为合理,利 用4种力学性能指标所测得同一竹龄毛竹材纤维饱和点略有差异。纤维饱和点随竹龄的变化规律相同,即从0.5~1.5年生降幅明显,大于1.5年生后趋于稳定。  相似文献   

8.
湿地松种植密度对纸浆材主要化学成分的影响   总被引:2,自引:0,他引:2  
对湖南省常德市周家店镇实验林场5种种植密度10年生湿地松的主要化学组分含量进行了统计分析,并对最佳种植密度进行了综合评定。结果表明:(1)种植密度间综纤维素含量变化范围为73.78%~75.56%;1%NaOH抽出物含量变化范围为22.64%~23.84%;种植密度对两者影响均不显著;(2)种植密度间苯醇抽出物含量变化范围为1.54%~2.14%;种植密度对苯醇抽出物含量影响显著;但两两种植密度间的差异程度有很大不同;(3)用于纸浆材最佳的种植密度是1.5m×1.5m。  相似文献   

9.
欧美杨和美洲黑杨树叶化学成分的研究   总被引:11,自引:0,他引:11  
分析了欧美杨(PopulusxeuramericanacvⅠ214)和美洲黑杨(P.deltoidescvHarvardexⅠ63/51)树叶在不同生长季节的化学成分。结果表明,在相同的采集季节,二种树叶的化学成分相差不大,都含有较多的蛋白质、氨基酸及丰富的无机元素。但是,各种化学成分均随采集季节的不同而变化。其中,蛋白质、氨基酸的含量随季节变化较大,其他成分变化较小。两种杨树叶蛋白质和氨基酸的含量接近或高于一些农、副产品,可以代替粮食等作为畜、禽饲料。  相似文献   

10.
以硬质合金作为衬底,分别采用了化学涂层(CVD)和物理化学涂层(PCVD)的技术涂复Ti(C,N)-TiN硬质膜,应用X射线光电子谱分析(XPS)技术,研究涂层表面化学成分、元素化学状态、物相组成及其随深度的变化。涂层表面由Ti,N,C,O和Co组成;表面物相包括TiN,TiO_x及CoO.随着深度的增加,Ti:N迅速变为1,而TiO_x和CoO含量急剧减少.  相似文献   

11.
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   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
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  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

20.
Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.  相似文献   

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