南平安曹下杉木林植被分析

通过 2 4 0 0m2 标准地调查 ,研究福建南平溪后安曹下 76年生杉木丰产林的山坡和山洼 2个地段的植物分布 ,结果表明 :老龄杉木林下蕨类植物的比例较天然林大 ,总共有 71科、119属、16 8种维管束植物 ,山坡地段的物种丰富度大大高于山洼地段 ,2个地段的科、属、种共有率分别为 6 3 38%、4 7 90 %、4 2 2 6 % ,说明老龄杉木林都是以热带成分为主 ,其中山洼地段的热带成分比例略高     

对青海省新时期农机化发展的思考

通过分析青海省农机化的现状和存在问题，提出了围绕农牧业结构调整，重点发展牧业机械化的发展思路和措施建议。     

杉木幼林抚育技术的综合评价和决策

本文在全面分析不同抚育技术对杉木生长、群体结构、林地植被物种多样性、生物量、水土流失和抚育成本的影响基础上，运用灰色局势决策理论对不同抚育技术进行多目标决策，结果表明：块状抚育和全垦抚育可提高杉木的保存率，并促进杉木幼林的生长；抚育技术对杉木群体树高和地径结构有一定的影响，尤其是对地径结构；全垦抚育的成本最大，不抚育最小，块状抚育居中；块状抚育有利于形成多层次的林分结构和林地植被物种多样性的提高。综合评价结果表明块状抚育是南方林区较好的杉木幼林抚育方式，它既能有效地减少林地植被对杉木的竞争，保持杉木的正常生长，又能降低抚育成本和保持地力及物种多样性。这对今后指导杉木幼林抚育具有重要的实践意义。     

Bark beetle community structure under four ponderosa pine forest stand conditions in northern Arizona

We studied the bark beetle guild (Coleoptera: Scolytidae) in the ponderosa pine forests of northern Arizona to explore if the species assemblages and relative abundance differ between managed and unmanaged stands. Four stand conditions were assessed: (1) unmanaged stands with high tree density, (2) thinned stands, (3) thinned and burned (with prescribed fire) stands and (4) stands that had been burned by stand replacing wildfires. The study was conducted in the ponderosa pine forests of the Coconino Plateau, northern Arizona. For several decades this area has been relatively free of bark beetle outbreaks despite the current overstocked condition of many stands. We found that a similar species assemblage composed of Dendroctonus frontalis, D. brevicomis, D. valens, D. approximatus, D. ponderosae, and Ips pini occurred across all four stand conditions over 3 years of study. The population levels of all these species were endemic across all stand conditions. The non-aggressive D. approximatus and D. valens were indicator species for thinned and unmanaged stands, respectively, but this was not consistent among years. The ambrosia beetle Gnathotrichus sp. and the bark beetle predator Enoclerus sp. consistently indicated stands burned by wildfire. In addition to our field experiment, we analyzed the historical pattern of attacks of bark beetles in our area of study. Our findings suggest that the pattern of attack of D. brevicomis (the only Dendroctonus species for which attacks have been reported) and Ips spp. has been through scattered small infestations in groups of 1–10 trees. Whereas small infestations by Ips spp. are increasing, those for D. brevicomis are decreasing. Although we agree that the high density stands in northern Arizona are in an “unhealthy” condition, our results do not show that they were supporting large bark beetle outbreaks. Our results challenge the theoretical assumptions about the relationship between stand structure, tree resistance and bark beetle performance.     

我国天然植物色素研究与开发初探

就天然植物色素的性质特点，种类及化学结构，提取与纯化，色素资源开发与重点开发对象和存在问题作了简述，为中国天然植物色素研究，开发，利用提供参考。     

利率市场化之真实含义

随着中国正式加入世贸组织，利率市场化改革已势在必行。之前，央行已制定出了利率市场化的大体框架并分步实施。当前流行于各类刊物的一些观点对利率市场化含义的理解尚不够准确。流行观点依据新老自由主义理论，强调市场“均衡利率”水平的重要性，忽略了利率结构问题。所谓的“均衡利率”实际上是不存在的，利率市场化改革的真实含义应当是：由中央银行决定基准利率水平，由市场决定利率结构。在银行业引入竞争机制是必要的前提。参9     

准噶尔南缘扇缘带种植业结构分析

通过对准噶尔南缘扇缘带种植业生产的分析及试验研究，提出了适合本地带农田的经粮结构、草经粮结构、林经草结构和专业化生产４种种植业结构类型。根据经济效益、生态效益和社会效益综合评定，认为采用草粮或林经草种植业结构类型，同时贯彻以牧为主、农牧结合的方针是本地带开发利用的最佳途径     

Pattern of Kirtland's warbler occurrence in relation to the landscape structure of its summer habitat in northern Lower Michigan

Studies of the endangered Kirtland's warbler in relation to landscape ecosystems were conducted from 1986–1988 on a large wildfire-burn surrounding Mack Lake in southeastern Oscoda County, Michigan. A landscape ecosystem approach was used to distinguish low- and high-elevation segments of the landscape, as well as 11 local ecosystem types. The ecosystems were distinguished by physiography, microclimate, soil, and vegetation. The early occurrence of the warblers was strongly related to landscape structure, i.e., to the broad low- and high-elevation areas and the local ecosystem types within them. Territories of male warblers were observed in 5 of the 11 ecosystems. The five ecosystem types where warblers were observed were characterized by (1) a physiography of level or rolling terrain; (2) soil series of Grayling, Graycalm, Montcalm, or Rubicon; (3) uplands with relatively warm temperature during the breeding season; (4) vegetation dominated by low sweet blueberry, bearberry, wintergreen, northern pin oak, blue stem grasses, and hair cap moss; and (5) canopy of relatively tall, dense, and patchy jack pine and oak. Landscape structure appears to be an important factor affecting the occurrence of the warbler in its summer habitat in northern Lower Michigan.     

不同日龄鸡睾丸发育及组织结构研究

本实验对不同日龄鸡的睾丸发育及组织结构进行了详细的研究。结果表明：不同日龄鸡左侧睾丸的重量和体积均略大于相应的右侧睾丸：１０５－１５０日龄段是鸡睾丸迅速发育的时期５，６０，１０５和１５０日龄时，精细管管径分别为４７．６２±３．０８，４９．０６±５．１８。５４．９０±９．３９和２２６．０９±４７．０７μｍ。精原细胞分Ａ，Ｂ两型，初级精弱细胞体积较大，核呈或椭圆形；次级精母细胞体积较小，数量较少；精子     

框筒结构楼板的温度裂缝分析

针对框筒结构楼板开裂现象，采用理想化模型对结构在内外温差作用下楼板的应力和变形进行参数计算，根据计算结果阐述了楼板角部穿透性斜裂缝的开展机理。分析了一批高层住宅楼的楼板开裂原因，提出了设计建议和施工中应重视的问题。