共查询到20条相似文献，搜索用时 296 毫秒
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离合弹簧在自动立木整枝机变速换向过程中起着重要的作用.本文分别从硬件设计和软件设计两方面介绍了基于虚拟仪器技术开发的自动立木整枝机离合弹簧性能测试系统,该测试系统支持不同类型信号的多通道数据采集和处理,能够实现信号的产生、数据实时采集、数据处理、分析、显示及存储等功能,并通过多次测试离合弹簧的实验,验证了该测试系统的实用性和可靠性. 相似文献
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提出并设计了大功率UPS负载试验系统及其数据采集与监视模块，讨论了该系统的原理及硬件结构和软件设计。该系统可测量UPS三相电压、电流、功率、频率和相位等参数，为大功率UPS电源的测试提供了有力的工具和实验手段。实验结果表明，该系统性能稳定、工作可靠。 相似文献
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介绍一种基于虚拟仪器和无线网络的通用数据采集系统,探讨了数据采集卡设置及系统各功能模块的实现方法.实验表明该数据采集系统采集的数据受环境干扰较小,且滤波、分析、存储及回放等功能强大.可适用于复杂环境下的多路多信号数据采集和分析,是一种比较理想的实时无线数据采集系统. 相似文献
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汽车自动变速器试验台的设计 总被引：6，自引：0，他引：6
根据自动变速器性能试验的要求，提出了FR式汽车自动变速器试验台的整体方案，介绍了各部分的结构和工作原理，并给出了整个系统的功能，该台架系统实用性强，具有很高的推广应用价值。 相似文献
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赵志国 《林业机械与木工设备》2006,34(9):32-35
提出了一种基于虚拟仪器测试汽车发动机性能的新方法,建立了基于虚拟仪器的汽车发动机性能远程测试诊断系统。该系统采用PC-DAQ方案,通过多传感器采集和数据融合,配以车载式PC机、数据采集卡和GPRS无线上网卡为主要硬件平台,以LabVIEW为软件开发平台,构成了汽车发动机性能的数据采集控制仪器。本文从硬件构成和软件功能上对整个系统的建立进行了详细介绍。实践表明,该检测系统具有较高的精度。 相似文献
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汽车变速器能量回馈试验系统动态特性仿真 总被引：1，自引：0，他引：1
通过系统设计和分析,建立了汽车变速器能量回收试验系统的数学模型,运用MATLAB/Simulink软件构建了该试验系统的仿真模型,并采用阶跃信号对其动态特性进行了仿真分析.通过仿真分析探讨了系统主要参数容积弹性模量、阻尼和转动惯量对试验系统性能的影响,得出了系统的变化特性曲线及相应的结论. 相似文献
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园林绿地自动喷灌技术是当今国际上较为流行实用的并具有一定先进性的园林绿地灌溉节水技术。目前,在我国部分地区园林绿地自动喷灌工程已经逐步推广和广泛设计应用。东北地区为克服地域差异以及寒冷低温、水源紧张、成本控制等多种因素影响,在松嫩平原某园林绿地内进行自动喷灌系统的设计及应用,包括场地勘察、数据采集、系统组成、设计特点、布管施工、应用效果等多个方面,取得良好的实际应用效果。该项目自动喷灌系统的实际应用打破了人们传统的思想认识——在东北地区地冻天寒的恶劣气候影响下无法进行园林绿地自动喷灌系统的设计和应用,为东北其它地区进行园林绿地自动喷灌系统的规划设计和实际应用提供一定的技术支持和参考依据。 相似文献
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This paper assesses recent lessons in scaling up agroforestry benefits, drawing on three case studies: fodder shrubs in Kenya, improved tree fallows in Zambia and natural vegetative strips coupled with the Landcare Movement in the Philippines. Currently more than 15 000 farmers use each of these innovations. Based on an examination of the main factors facilitating their spread, 10 key elements of scaling up are presented. The key elements contributing to impact were a farmer-centered research and extension approach, a range of technical options developed by farmers and researchers, the building of local institutional capacity, the sharing of knowledge and information, learning from successes and failures, and strategic partnerships and facilitation. Three other elements are critical for scaling up: marketing, germplasm production and distribution systems, and policy options. But the performance of the three case-study projects on these was, at best, mixed. As different as the strategies for scaling up are in the three case studies, they face similar challenges. Facilitators need to develop exit strategies, find ways to maintain bottom-up approaches in scaling up as innovations spread, assess whether and how successful strategies can be adapted to different sites and countries, examine under which circumstances they should scale up innovations and under which circumstances they should scale up processes, and determine how the costs of scaling up may be reduced.
相似文献12.
原木检尺进位方法对木材规格和材积的影响分析 总被引：2，自引：1，他引：2
通过随机抽取 316根原木 ,分别采用国家标准原木检尺方法与南方一些地区实际使用的原木检尺方法进行计算、比较和分析 ,认为不标准的原木检尺进位方法降低了木材规格和材积 ,损害了林农和国家利益 ,干扰了林业资源管理工作 相似文献
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《林业研究》2019,(6)
The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant. The model of West, Brown and Enquist(WBE model) considers that a 3/4 scaling exponent of metabolic rate versus total mass to be optimal for each plant and has been confirmed numerous times. Although leaf area is a better proxy of the metabolic rate than leaf mass, few studies have focused on the scaling exponent of leaf area versus total mass and even fewer have discussed the diversification of this scaling exponent across different conditions. Here, I analyzed the scaling exponent of leaf area versus total mass of sample plots across world plants. I found that as the plant grows, it allocates fewer resources to photosynthetic tissues than expected by the WBE model. The results also empirically show that this scaling exponent varies significantly for different plant leaf habit, taxonomic class and geographic region. Therefore, leaf strategy in response to environmental pressure and constraint clearly plays a significant role. 相似文献
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Rupert Seidl Chris S. Eastaugh Koen Kramer Michael Maroschek Christopher Reyer Jarosław Socha Giorgio Vacchiano Tzvetan Zlatanov Hubert Hasenauer 《European Journal of Forest Research》2013,132(5-6):653-666
Scaling is widely recognized as a central issue in ecology. The associated cross-scale interactions and process transmutations make scaling (i.e. a change in spatial or temporal grain and extent) an important issue in understanding ecosystem structure and functioning. Moreover, current concepts of ecosystem stewardship, such as sustainability and resilience, are inherently scale-dependent. The importance of scale and scaling in the context of forest management is likely to further increase in the future because of the growing relevance of ecosystem services beyond timber production. As a result, a consideration of processes both below (e.g. leaf-level carbon uptake in the context of climate change mitigation) and above (e.g. managing for biodiversity conservation at the landscape scale) the traditional focus on the stand level is required in forest ecosystem management. Furthermore, climate change will affect a variety of ecosystem processes across scales, ranging from photosynthesis (tree organs) to disturbance regimes (landscape scale). Assessing potential climate change impacts on ecosystem services thus requires a multi-scale perspective. However, scaling issues have received comparatively little attention in the forest management community to date. Our objectives here are thus first, to synthesize scaling issues relevant to forest management and second, to elucidate ways of dealing with complex scaling problems by highlighting examples of how they can be addressed with ecosystem models. We have focused on three current management issues of particular importance in European forestry: (1) climate change mitigation through carbon sequestration, (2) multi-functional stand management for biodiversity and non-timber goods and services and (3) improving the resilience to natural disturbances. We conclude that taking into account the full spatiotemporal heterogeneity and dynamics of forest ecosystems in management decision-making is likely to make management more robust to increasing environmental and societal pressures. Models can aid this process through explicitly accounting for system dynamics and changing conditions, operationally addressing the complexity of cross-scale interactions and emerging properties. Our synthesis indicates that increased attention to scaling issues can help forest managers to integrate traditional management objectives with emerging concerns for ecosystem services and therefore deserves more attention in forestry. 相似文献
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对塑木地板进行抗弯性能测试,分别选取25％和75％两种应力水平进行疲劳／蠕变试验。研究了塑木地板在疲劳／蠕变复合作用下的断裂机理。结果表明：随着应力水平的增加,蠕变应变也随之增加,75％应力水平时产生的应变为25％应力水平时的3倍;其疲劳／蠕变曲线与纯蠕变曲线十分相似;在25％的应力水平作用后,材料的剩余抗弯强度为原来的94％～97％。 相似文献
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作为森林生态系统一个重要的呼吸通量,叶片呼吸在森林碳循环中扮演着重要的角色。开展叶片呼吸的机理及其影响因子研究,有助于构建大气和植被之间的呼吸通量模型,预测分析气候变化对森林生态系统生产力和碳源汇功能的影响。通常采用Li - 6400光合测定系统和LAI - 2000树冠分析仪测定森林生态系统叶片呼吸速率。叶片呼吸是一个复杂的生物化学过程,受到大气温度、CO2浓度、土壤水分、叶片寿命、叶龄、比叶面积、叶片氮含量等多种因子的影响。叶片呼吸的日变化通常呈单峰曲线,与温度变化大体一致; 生长季早期和晚期的呼吸速率通常高于中期; 叶片在冠层着生位置影响其呼吸速率,冠层上部叶片的呼吸速率要高于冠层下部叶片。今后叶片呼吸研究应围绕以下4个关键问题:1) 模型构建时需要考虑叶片呼吸的温度驯化;2) 叶片呼吸在昼夜交替时内在调节机制;3) 从叶片呼吸到冠层呼吸的尺度转化;4) 加强和完善叶片呼吸影响因子研究。 相似文献
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林分径阶蓄积量与材种出材量测算的研究 总被引：2，自引：0，他引：2
研究了林分径阶蓄积量与材种出材量的估测模型,其基本原理是应用相对树高曲线法测定林分径阶蓄积量,应用一致性削度方程法计算径阶单木材种出材率;相对树高曲线法与一致性削度方程法是基于胸径和树高两个测树因子的二元立木材积测定系统,通过建立较完善的数学模型改进计算方法,提高估测效果. 相似文献