Results 11 to 20 of about 850,130 (216)
He jishu国际原子能机构（International Atomic Energy Agency，IAEA）与美国医学物理学家协会（American Association of Physicists in Medicine，AAPM）联合制定的外照射光子束小野静态射野剂量学操作规程（TRS-483）中提供的小野射野输出修正因子（kQclin,Qreffclin,fref）未考虑均整模式（Flattening Filter，FF）、非均整模式（Flattening Filter Free，FFF）束流间差异 ...
张 国龙 +8 more
doaj +1 more source
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Decomposition is the transformation of dead organic matter into its inorganic constituents. In most biomes, decomposition rates can be accurately predicted with simple mathematical models, but these models have long under‐predicted decomposition in globally extensive ...
Heather L. Throop +8 more
wiley +1 more source
Jixie chuandong, 2015 针对现有测量方法存在的问题,基于测量状态与加工状态一致的检测原理,设计了环面蜗杆精度测量原理。通过设置自动标定程序和高精密时栅转台使系统自动建立三维空间的测量坐标系,并利用坐标旋转法测得测头的回转半径。采用随动控制方式来测量环面蜗杆各齿面的点在测量坐标系中的坐标值,从而得到环面蜗杆的精度。系统采用金字塔式的结构使系统更稳定、可靠性强。通过实验,验证了本方案的可行性,测得环面蜗杆螺旋线的误差为±4μm。对系统进行等精度重复性实验,系统的极差为0.9μm,方差分析说明各测量点的误差值无显著差异。
陈锡侯 +3 more
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Shuitu Baochi Xuebao, 2021 为减小染色法测量坡面水流流速的误差，提高染色法测量准确度，根据染色示踪剂在水中扩散引起颜色发生变化的特性，结合漫反射型模拟量光电颜色传感器和数据采集卡采集信号，通过小波变换对信号进行去噪，研发一种基于光电传感技术的薄层水流流速测量系统。以流量法为参照，确定该系统传感器最优数据采集距离为0.6~0.8 m；传感器数据采集距离为0.7 m时，该系统测量数据最小相对误差仅为0.48 ...
白凯强 +7 more
doaj
Inferring alternative ecosystem states with field survey data
Methods in Ecology and Evolution, EarlyView.Abstract Many ecosystems potentially exhibit alternative stable states, where distinct states can coexist under identical environmental conditions. While simulation models have generated key hypotheses in alternative stable states theory, they often rely on scale‐free parameters disconnected from real ecosystems.
Ning Chen +10 more
wiley +1 more source
智能城市应用随着科技的不断发展，激光雷达测量系统在水库安全检测中的应用逐渐成为研究和实践的焦点，基于其高精度、高效率的特点，为水库工程的安全性评估和监测提供了重要的技术支持，有望成为水利工程领域的一项创新技术。文章通过对激光雷达测量系统的概述和优势进行阐述，深入探讨了其在水库安全检测中的具体应用。
绍青 周 +3 more
semanticscholar +1 more source
Comprehensive framework for assessing and optimizing existing research networks
Conservation Biology, EarlyView.Abstract Conservation, monitoring, and research networks, or collections of ecological research sites unified under a common mission of data collection or a research mission, are essential infrastructure for understanding large landscapes. However, most networks developed opportunistically over decades rather than through systematic design, creating ...
Alyson East +2 more
wiley +1 more source
Conservation Biology, EarlyView.Abstract The design of experiments to investigate the combined effects of multiple stressors requires exposing target organisms to multiple combinations of stressor doses. Concurrent manipulation of stressors is often infeasible with wildlife, but long‐lasting health effects allow individual health to be used as an integrator of prior stressor exposure.
Enrico Pirotta +24 more
wiley +1 more source
Assessing differences among elasmobranch nurseries to aid conservation based on a genomics framework
Conservation Biology, EarlyView.Abstract Elasmobranch nurseries often differ in environmental conditions, demographics, and use patterns. These differences affect the distribution of genetic variation among nurseries. However, conservation and management strategies often fail to account for such differences because they are difficult to characterize.
Dominic G. Swift +8 more
wiley +1 more source
, 2013 本实用新型涉及一种测量波像差的系统，包括干涉仪以及与干涉仪处于同一光路上的平面反射系统；待测光学系统置于干涉仪和平面反射系统之间；平面反射系统是液体反射镜；干涉仪、待测光学系统以及液体反射镜自上而下依次设置在同一光路上。本实用新型提供了一种不仅可用来检测小口径光学系统波像差 ...
康福增, 赵卫, 张周锋, 谢永军
core +1 more source