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Search Results: 1 - 10 of 44114 matches for " 关亚彬 "
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东北地区植被多样性的研究ⅰ.寒温带针叶林区域垂直植被多样性分析
,陈铁,,周以良
应用生态学报 , 1997,
Abstract: 用renyi及hill多样性指数簇相结合的方法,对中国寒温带针叶林区域垂直植被的区系多样性、生活型多样性及叶级多样性进行了分析,将亚高山矮曲林带(ⅰ)、寒温性针叶疏林带(ⅱ)、山地上部寒温性针叶林亚带(ⅲ1)、山地中部寒温性针叶林亚带(ⅲ2)和山地下部寒温性针叶林亚带(ⅲ3),划分为生物多样性的特殊性植被带(ⅰ)、过渡性植被带(ⅱ)及生物多样性的交汇性植被亚带(ⅲ1)、稀疏性植被亚带(ⅲ2)和富集性植被亚带(ⅲ1).对ⅰ、ⅱ带及ⅲ1亚带的植被宜采取保护性经营对策,对ⅲ2、ⅲ3亚带,采取恢复和提高其生物多样性,促进植被进展演替的经营对策.
区域生态安全格局:概念与理论基础
马克明?,傅伯杰?,黎晓,
生态学报 , 2004,
Abstract: 提出区域生态安全格局概念的提出,适应了生态系统恢复和生物多样性保护的发展需求。针对区域生态环境问题,通过干扰排除以及空间格局规划和管理,能够保护和恢复生物多样性,维持生态系统结构、功能和过程的完整性,实现对区域生态环境问题的有效控制和持续改善。区域生态安全格局的研究对象具有针对性、研究尺度具有区域性、研究问题具有系统性、研究手段具有主动性。它强调区域尺度的生物多样性保护、退化生态系统恢复及其空间合理配置、生态系统健康的维持、景观生态格局的优化、以及对社会经济发展需求的满足。它更加强调格局与过程安全及其整体集成,将生态系统管理对策落实到具体的空间地域上,实现管理效果的直观可视。相关理论,景观生态学、干扰生态学、保护生物学、恢复生态学、生态经济学、生态伦理学、和复合生态系统理论等为其提供了坚实的理论基础。区域生态安全格局不存在一个固定标准,人类对生态系统服务功能需求的不断变化是生态系统管理的根本原因。实现区域生态安全不但要以社会、经济、文化、道德、法律、和法规为手段,更要以其不断发展对生态系统服务功能的新需求为目标逐步进行。区域生态安全格局研究对于解决区域生态环境问题具有不可替代的作用,具有广阔应用前景。
采用NSGA-Ⅱ算法的面齿轮副小轮 拓扑修形多目标优化
NSGA-Ⅱ Based Multi??Objective Optimization on Topologically Modified Pinions for Face Gear Pairs

付学中,方宗德,,李建华
- , 2017, DOI: 10.7652/xjtuxb201707015
Abstract: 为合理确定面齿轮副小轮的修形参数,设计了均由2段抛物线与1段直线组成的直齿小轮齿廓和齿向修形曲线,将由三次B样条拟合得到的修形曲面与理论齿面相叠加来构造拓扑修形齿面。采用带精英策略的快速非支配排序遗传算法(NSGA-Ⅱ),结合面齿轮副的几何接触分析(TCA)和承载接触分析(LTCA)技术,提出了以修形曲线参数为优化变量,使抛物线几何传动误差曲线两端对称、接触印痕限制在齿宽中部、承载传动误差波动幅值最小的小轮拓扑修形多目标优化设计方法,并编制了相应的Matlab程序。算例表明:优化修形参数后得到了对称的抛物线几何传动误差和位于大轮齿宽中部的接触印痕,并大幅度减小了承载传动误差波动,从而可有效降低安装误差敏感性和齿轮副的振动、噪声。
To reasonably determine the technical parameters in profile modification of face gear pairs, a tooth profile and an axial modification curve both composed of two sections of parabola and a straight line on a spur pinion are created. A topologically modified tooth surface can be represented as a superposition of theoretical tooth surface and the deviation surface obtained by cubic B??splines fitting on the tooth surface grid. Based on the tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA) of the face gear pairs, taking the parabolic transmission error curve being symmetrical in geometry, the contact path being limited in the central tooth width, and the minimum wave amplitude of loaded transmission errors as the three optimization objectives, a multi??objective optimization model is established, and the corresponding programs are developed by software Matlab. The fast elitist non??dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) is selected as the multi??objective optimization algorithm. An optimization example shows that the present method obtains symmetric parabola geometry transmission error and the contact path in the middle of gear tooth width, which greatly reduces the wave amplitude of loaded transmission errors, hence effectively reduces installation error sensitivity, vibration and noise
The regional pattern for ecological security (RPES): the concept and theoretical basis
区域生态安全格局:概念与理论基础

MA Keming,FU Bojie,LI Xiaoya,GUAN Wenbin,
马克明
,傅伯杰,黎晓,

生态学报 , 2004,
Abstract: The concept of the Regional Pattern for Ecological Security (RPES) was proposed. Aimed at regional ecological and environmental problems, a spatial pattern can be designed and managed to conserve and restore biodiversity, to maintain ecosystem integrity of structures, functions and processes, and to realize the effective control and continuing improvement of the specific problems on the basis of disturbance removal. Which was accordant with the developments of ecological restoration and biological conservation. The RPES study directly pointed to the ecological problems and focused on the ecological restoration and biological conservation at regional scale, the study was systematic, and the approach was active. It emphasized on the restoration and configuration of degraded ecosystems, the maintenance of ecosystem health, the optimization of landscape pattern, and the spatial pattern adjustment adapted to the developments of the society and economics at regional scale. The spatial pattern visualized the strategies of ecosystem management, and ensured the security of ecological pattern and process as well as their integration at regional scale. The relevant theories, landscape ecology, disturbance ecology, conservation biology, restoration ecology, ecological economics, ecological ethics, and the integrated ecosystem theory, supplied solid theoretical supports to the concept. The RPES has not a fixed standard, but the varied human requirement to ecosystem services is the root reason for implementing the ecosystem management. Therefore, it should be realized not only by the means of social, economic, cultural, moral, law, and regularity methods, but also need to be consistent to the developing demands of human society to ecosystem services. The RPES study will play a key role in dealing with regional ecological and environmental problems, therefore has a brighter future in ecological restoration and biological conservation.
气相色谱法测定饮用水源水中六氯丁二烯方法研究
陈丽华, 袁雪芬, 杨润, 汪小丰,, 景武, 王永
中国公共卫生 , 1999,
Abstract: ?以高纯氮为流动相,以ApiezonL为固定相,利用电子捕获检测器对饮用水源水中六氯丁二烯进行气相色谱测定,同时研究测定过程中各种影响因素,选择了最佳实验条件。分析结果表明,此法具有简单快速、准确和灵敏等特点。
The Analysis of Lubricating Oils by On Line Coupled Packed Capillary Liquid Chromatography and High Temperature Capillary Gas Chromatography
填充毛细管液相色谱-高温毛细管气相色谱在线联用分析润滑油

江涛,
色谱 , 1998,
Abstract: 建立了一套填充毛细人相色谱-高温毛细管气相色谱在线联用装置,并应用于润滑油的全组分分析,用正相填充毛细管柱液相色谱法进行样品族分离,将润滑油分成烷烃、单环芳烃、双环芳烃、三环芳烃及胶质(多环芳烃和极性物);特殊设计的多储存位接口可完成一次LC进样,对样品所有族组成的在线切割、贮存并无损失转入GC分析,保证了复杂样品全组分分析的准确性和定量,缩短了分析时间。GC分析结果给出各族组分的相对含量和碳数分
The Key Problems in Miniaturization of Gas Chromatograph and Liquid Chromatograph
气相色谱和液相色谱微型化中的关键问题


色谱 , 2003,
Abstract: 目前分析仪器微型化的浪潮汹涌澎湃,人们以极大的热情投入到这个浪潮中。从世界各地的实验室里出现的原理型样机看上去是如此的微小、简洁和令人惊诧,有如此多的加工工艺可以应用在微型器件的加工和组合上从非常昂贵的、在超净房间才能使用的精密仪器设备和工艺到土法上马、在普通房间就能操作的加工手段。它的前景是那样的诱人,引无数英雄一试身手。  从1986年我第一次听说微型气相色谱仪并看到相关文章,就认定它是色谱发展的未来。1987年底我在荷兰第一次看到它时,就下决心今生一定研究微型色谱,因为它从观念上、认识上打开了分析仪…
大孔树脂吸附骨碎补总黄酮特性的研究
陈顺,
中国中药杂志 , 2007,
Abstract: 骨碎补为水龙骨科多年生附生蕨类植物槲蕨Drynariafortunei(Kunze)J.Sm的根茎。传统中医认为骨碎补性味苦温归肾肝经,具有补肾强骨、续伤止痛功效,用于肾虚腰痛、耳鸣耳聋、牙齿松动,跌扑闪挫,筋骨折伤;有报道称骨碎补总黄酮有刺激骨生长[1]、预防骨质疏松[2]和抗炎作用[3]。大孔树脂对于黄酮类化合物是较理想的吸附剂,但应用于骨碎补总黄酮的研究还不多见。作者比较了7种不同型号的大孔树脂对骨碎补总黄酮吸附性质,对其中效果....
纵向数据下广义线性模型的稳健二次推断函数估计
晓妮,
- , 2018, DOI: 10.13543/j.bhxbzr.2018.02.017
Abstract: 针对纵向数据下的广义线性模型,为了有效控制离群点对估计的影响以及进一步提高估计的效率,利用二次推断函数(QIF)改进加权的指数得分函数,得到了模型参数有效且稳健的二次推断函数估计(ERQIF),并证明了在一定条件下所得估计的相合性和渐近正态性。数值计算结果进一步表明,当离群点存在或工作相关矩阵被错误指定时,所得估计有稳健的模拟结果。
Abstract:This paper presents an efficient and robust estimation method for generalized linear models with longitudinal data. By using a quadratic inferential function (QIF) to improve the weighted exponential score function, we can obtain an effective and robust quadratic inferential function(ERQIF). Under some regularity conditions, the resulting estimators are consistent and asymptotically normal distributed. Finally, simulation studies show that the proposed estimators have robust and efficient numerical results, even when many outliers are included and the working correlation matrix is misspecified.
Ecological studies on the relationship between the process of desertization and vegetation dynamics in the west of northeast china:community diversity and desertization process
中国东北西部地区沙质荒漠化过程与植被动态关系的生态学研究——群落多样性与沙质荒漠化过程

GUAN Wen Bin,

生态学报 , 2000,
Abstract: 依据东北西部沙质荒漠化地区植被的分类与排序,分析了不同演替梯度上植被群落多样性指数与DCA排序坐标值的相关关系,利用其探讨群落多样性与沙质荒漠化过程的关系;科尔沁沙地、呼伦贝尔沙地,1)植物群落的生态优势度λ、Renyi的均匀度E1与群落分布的地下水位有显著的相关关系;2)植物群落Hill的多样性指数H0,H1、Hill的均匀度Eh、Hill指数的均匀度E′1与海拔、湿润系数、Thornthwaite指数、降水量、地下水位、放牧干扰等有显著的相关关系;3)植物群落Renyi的多样性指数N0,N1、Heip修正的均匀度Ep、Alatalo修正的均匀度E′h与经度、温暖指数、冷暖指数、Thornthwaite指数、土壤有机质、地下水位、放牧等干扰有显著的相关关系。4)呼伦贝尔沙地的完工-海拉尔沙带,樟子松林、贝加尔针茅羊草草甸草原;科尔沁沙地的油松林、羊草草甸草原、丛生禾草草原具有较高的多样性,各群落类型随着沙质荒漠化过程的逐渐加剧,物种丰富度逐渐降低,其递减趋势分为旱生沙化系列、湿生沙化系列、盐水至水生系列。按各群落类型的物种丰富度递减顺序可分为6个级别,6个级别所含的群落类型分别对应着稳定沙地(A、B),固定沙丘(C),半固定沙丘(D),半流动沙丘(E),流动沙丘(F)。
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