丛生竹根系抗拉力学特性

竹林是具有水土保持功能的一种重要植被,其地下根系力学性能好坏是影响竹林固土力学作用的重要因素。为了了解丛生竹林地下根系的抗拉力学特性,利用自制的植物根系抗拉力学特性野外便携实验系统,对料慈竹、绿竹、龙竹、香竹4种丛生竹根系进行了现场拉伸实验,测量这4种丛生竹不同直径根系的抗拉力、应变,并通过计算得到抗拉强度和弹性模量。结果表明,4种丛生竹根系最大抗拉力与根直径的关系呈幂函数正相关增长,抗拉强度与根直径的关系呈幂函数负相关增长。根系平均抗拉力分别为料慈竹(59.47 N)、香竹(58.65 N)、龙竹(43.51 N)、绿竹(40.80 N),平均抗拉强度依次为龙竹(30.24 MPa)、料慈竹(23.14 MPa)、绿竹(22.83 MPa)、香竹(18.14 MPa),平均极限应变较为接近,在14%～18%之间,平均弹性模量值为龙竹(169.86 MPa)、料慈竹(166.37MPa)、绿竹(158.36 MPa)、香竹(135.56 MPa),最高峰值达到350 MPa。4种丛生竹相比,龙竹根系的综合抗拉力学性能最好,其次是料慈竹和绿竹,最后是香竹。与常见造林树种油松、落叶松、白桦相比,丛生竹根系具有较好的抗拉力学性能。     

加快江西省盆景发展的相关对策分析

据相关资料显示,2 0 0 1年世界花卉盆景贸易额达12 2亿美元,行业产值已达2 0 0 0亿美元;2 0 0 2年中国花卉盆景出口创汇总额突破一亿美元,比上年增长2 0 %以上;2 0 0 3年春节深圳花市销售额首次超过亿元,比2 0 0 2年春节多一倍,并反映出两大特点:一是花卉销售中高档盆景位居榜首,二是反季节花卉品种增多。由于受生产成本、环境保护、经济增长速度等因素的影响,发达国家花卉盆景业的发展步子已经放慢,有的甚至出现下降趋势,而一些气候适宜、生产成本低廉的发展中国家,花卉盆景生产正在迅速崛起,成为新的主要花卉盆景生产出口国。全球花卉盆景…     

灵岩寺及千佛殿罗汉的彩塑艺术浅论

灵岩寺坐落在山东省长清县城东南３１．５公里处的万德镇境内的灵岩山阳,是东岳泰山十二支脉之一,在泰山主峰西北麓二十公里处,海拔６８３．７米。灵岩山始名方山,北魏郦道元的《水经注》称其为玉符山。方山、玉符山皆是以山形而得名。因方山峰顶雄伟高大,四面如削,方方正正,很像古代帝王的方印。至于一灵岩”一名,则是和朗公和尚的故事有关。《神僧传》云：“朗公和尚说法泰山北岩下,听者千人,石为之点头,众以告,公曰：此山灵也。”遂名灵岩。金舆谷东天门南侧的峰岭上,有一数丈高的怪石,被称为朗公石,远远望去,酷似一驼背…     

浅论西部边疆五省区的发展

西部大开发战略的实施为西部地区的发展提供了历史性机遇.西部边疆五省区在西部经济发展中扮演着重要的角色,加快其发展对于西部大开发具有重要意义.西部边疆五省区具有显著的资源优势、区位优势和政策优势,经济发展的潜力巨大;同时,它们在人口、经济、生态环境等方面所面临的一系列共同的问题,又严重阻碍了其发展步伐.因此,如何抓住西部大开发的机遇,制订有效的对策和措施,扬长避短、进一步加快其发展,是西部边疆五省区应认真面对的问题.     

昆明市地貌条件与城市发展浅论

本文首先分析了昆明能成为大城市的地貌基础及其平面形态与地貌的关系，进而分析了自然地貌类型对城市发展的影响，最后分区论述了地貌条件与城市发展的适宜性，并对今后城市发展的宏观调控方向提出了建设性意见。     

浅论目前环境下乡镇企业的发展问题(摘要)

推进乡镇企业的“治理、整顿”工作,首先应正确估价和分析乡镇企业存在的诸问题对国民经济结构失调形成的作用程度:乡镇企业对我国农业与工业比例关系的影响具有双重性,即加剧与延缓不协调性;乡镇企业对我国工业结构的不合理性的影响大约为15％。从而表明乡镇企业并非我国目前经济困窘局面产生的主要引致因素,“大砍大压”的思想是错误的;其次,乡镇企业的治理整顿不可毕其功于役,应积极贯彻有保有压,逐步平稳调整的方针;第三,在具体的工作中,一要坚持企业的结构调整,以“并转”为主,“关、停”为辅,二要加强企业的技术改造,三要慎思行政手段,强化宏观     

浅论易滑地层

我国不少滑坡研究者已使用过“易滑地层”一词。本文试图概述一下易滑地层及其某些特性。 实际资料表明,滑坡分布与地层岩性密切相关。这就是说,滑坡集中分布于某些地层出露区,下面先来论述一下地层问题。     

浅论会计职业道德

目前我国正处于计划经济向市场经济的转型时期,出现了多种价值观念的相互撞击与交融。计划经济下的道德标准受到了来自市场经济的强烈冲击,迫使会计人员的职业道德面临着严峻的考验,会计职业道德水准也出现了滑坡,不少人在物质财富中失去方向,贪污舞弊、做假账、滥用职权行为等屡见不鲜。对于当今会计职业道德的严重丧失,重塑会计人员的职业道德形象已成为当务之急。会计职业道德的滑坡严重影响着会计工作。本文就会计职业道德的意义、现状及对策提出了意见     

浅论地质工作的发展趋势

资源、环境是人类生存和发展的最基本条件。在新中国成立后的半个多世纪里,我国以地质勘探为主的地质工作呈现一派繁荣的景象,通过国家统一部署的地质工作, 既深入地了解了中国大陆的基本地质情况,又解决了经济建设所需要的基础矿产原料,为中国经济发展     

Long-term landscape development of the Coloradofjella plateau, central Spitsbergen, Svalbard

The development and age of the present geomorphology and superficial material of the Coloradofjella plateau, Spitsbergen, have been investigated through field surveying and laboratory sediment analyses. The focus was specifically on the role of glacial erosion and periglacial processes. The summit plain is deeply incised with large V-shaped valleys. Extensive networks of ice wedge polygons indicate that the fine-grained regolith is at least a few metres thick. An abundance of coarse-grained gabbroid erratics, clearly derived from sources further to the east, are distributed over parts of the summit plain. A vertical-walled dolerite dyke protruding up to 4 m above the adjacent surface shows no sign of glacial erosion. Our findings confirm that the present bedrock geomorphology and regolith in the summit plain survived at least the Late Weichselian glaciation. This is best explained by the ice sheet having been cold-based throughout its existence on the summit plain. Cold-based conditions imply that permafrost survived the last glacial cover. Based on the geomorphic evidence and estimates of Late Cenozoic erosion, we suggest that the present summit plains roughly represent the remains of a preglacial surface.     

城市人工地貌演变过程及机制的研究——以大连市为例

城市人工地貌是城市中由人类活动作用形成的各种高差起伏的人工建筑体的组合形态;本文以大连市为例,探讨了城市人工地貌的演变过程及机制,大连市城市人工地貌演变过程分为单核心扩散-绕大连湾的马蹄形延展-环形带状更新扩散期-多核心扩散、带状延展期;自然地质条件是演变的基础,城市规划是主导因素,社会经济发展水平是其推动力     

Soil development on stable landforms and implications for landscape studies

Soil development parameters include a wide variety of morphological, chemical, and mineralogical parameters, but some of the best indicators of time and surface stability are derived from field morphology. Over long time-spans, the most common time function for soil development is exponential or logarithmic, in which rates decrease with increasing age. Over shorter time-spans in semi-arid and moister climates, Holocene and Pleistocene soil development functions appear as linear segments, with Holocene rates about 10 to 50 times those of Pleistocene rates. In contrast to significant temporal variation in rates, geographical variation in rates within (a) the southern Great Basin and (b) the east Central Valley of California is on the order of 2 or 3 times. When comparing soil development indices of the semi-arid Great Basin to those of moister central California, Holocene rates are similar, but Pleistocene rates are more than 10 times slower in the Great Basin. In a range of climatic settings, the reasons for declining rates over time are several and are complexly related to erosional history, fluxes in water and dust related to climatic changes, rates of primary mineral dissolution, and intrinsic soil processes.     

Desert pavement development and landscape stability on the Eastern Libyan Plateau, Egypt

Desert pavement surfaces of the eastern Libyan Plateau in central Egypt represent a stable landscape preserving Middle and Upper Paleolithic artifacts. Detailed measurements of pavement clasts indicate significant variability in clast size, density, lithology and orientation between pavements, but no spatial relationship among any of these pavement variables over the study area. Pavement characteristics are unrelated to local geomorphic features including slope gradient and aspect, suggesting a desert pavement surface that has developed without significant influence from transporting mechanisms such as overland flow and slope failure. Meridional vertical cracks in surface clasts implicate thermal stresses due to diurnal solar variation as a mechanical weathering process, whereas the presence of a clast-free silty layer within all soil profiles indicates that these are accretionary pavement surfaces that have grown upward over time. The desert pavement in this region has likely developed in situ through mechanical breakdown of surface clasts and desert pedogenesis, indicating long-term stability for this region and minimal taphonomic effects on artifacts > 2 cm in diameter deposited on this surface over the last ca. 100 ka.     

面向治理的地理学发展刍议

“四个面向”（面向世界科技前沿、面向经济主战场、面向国家重大需求、面向人民生命健康）已成为新时代中国科学发展的指针。治理是一个反映“四个面向”的国际前沿研究领域,也是地理学和其他学科研究的焦点。围绕地理学如何应对治理这一关键问题,基于人地耦合的理念,系统梳理国内外地理学进行治理研究的轨迹与特点,从价值、思想、方法、技术4个维度发掘面向治理的地理学发展路径,紧密联系地理学发展动态及治理现代化的实践,从基础研究、平台建设、人才培育3个方面提出发展策略。提升中国地理学在国际治理研究中的影响力,促进地理学与其他学科的交叉融合,将自然与人文有机结合的理念应用于社会治理,增进居民福祉,并服务国家战略和区域可持续发展。     

On models for landscape connectivity:a case study of the new-born wetland of the Yellow River Delta

The models for landscape connectivity are distinguished into models for line connectivity, vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for vertex connectivity, and for network connectivity have long been studied and have become ripe, the model for patch connectivity is paid special attention in this paper. The patch connectivity is defined as the average movement efficiency (minimizing movement distance) of animal migrants or plant propagules in patches of a region under consideration. According to this definition, a model for landscape connectivity is mathematically deduced to apply to GIS data. The application of model for patch connectivity in the new-born wetland of the Yellow River Delta shows patch connectivity has a negative interrelation with human impact intensity and landscape diversity.     

On models for landscape connectivity: a case study of the new-born wetland of the Yellow River Delta

The models for landscape connectivity are distinguished into models for line connectivity, vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for vertex connectivity, and for network connectivity have long been studied and have become ripe, the model for patch connectivity is paid special attention in this paper. The patch connectivity is defined as the average movement efficiency (minimizing movement distance) of animal migrants or plant propagules in patches of a region under consideration. According to this definition, a model for landscape connectivity is mathematically deduced to apply to GIS data. The application of model for patch connectivity in the new-born wetland of the Yellow River Delta shows patch connectivity has a negative interrelation with human impact intensity and landscape diversity.     

On the modes of urban-rural networking development in China

1 IntroductionFor nearly half a century, in developed countries, the major problem of development has been lying in cities, but in underdeveloped ones, the problem lies in rural areas as well as in cities. Therefore, the development of both urban and rural areas is the theme of development of developing countries. China has the largest rural population in the world. With a high percentage of rural population, China is a developing country in which the rural social and economic activities take…     

我国林木种苗发展对策思考

<正> 一、我国林业发展新形势对林木种苗提出了新要求 从新世纪开始,我国进入了全面建设小康社会加速推进社会主义现代化的历史时期,正在努力开创生产发展、生活富裕和生态良好的文明发展道路。在这个历史进程中,林业肩负着重大的使命,确立了在国民经济和社会