Results 71 to 80 of about 64,092 (179)
Scenarios and strategies for future‐proofing ecosystem management under climatic novelty
Conservation Biology, EarlyView.Abstract Climate change is driving unprecedented declines in dominant, habitat‐forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning ...
Lauren T. Toth +14 more
wiley +1 more source
Improvement of chaotic measuring circuits(混沌测量电路的改进)
Zhejiang Daxue xuebao. Lixue ban, 2001 混沌测量是一种全新的测量原理，它能用极不稳定的测量系统实现高精度测量.本文对恒流式混沌测量电路作了进一步的改进.实验结果表明，它能明显提高混沌轨道的线性度和稳定性.
JINWen-guang(金文光) +1 more
doaj +1 more source
Research on stitching measurement technology for large aspheric optics during grinding process [PDF]
, 2016 大口径非球面光学元件能校准像差，提高像质，减小光学系统的体积和重量，并增加光学系统的可靠性，因此其被广泛应用于航空航天、国防等先端科研技术领域。磨削阶段大口径非球面元件的面形检测是制约其推广应用的重要因素。坐标测量技术是实现磨削阶段光学元件面形检测的重要手段，但是该技术在解决大口径、高陡度非球面元件的高精度测量上仍存在一系列技术问题需要解决，比如自主开发的轮廓仪因成本高昂大多难以推广，轮廓仪测头传感器有效测量行程不足，待测工件的大尺寸相比轮廓仪运动量程受限 ...
叶世蔚
core
Structured machine learning modeling to support conservation of deep‐sea benthic biodiversity
Conservation Biology, EarlyView.Abstract Biodiversity monitoring programs need to deliver accurate, timely, and actionable predictions. To establish a predictive monitoring program for deep‐sea benthos of the Santos Basin, Brazil, we developed a two‐stage structured model that allowed comparison of biodiversity predictions obtained from environmental simulations (2M‐Sim).
Gustavo Fonseca +23 more
wiley +1 more source
UPLC测定食用油中的3种香兰素类物质含量Determination of three vanillin compounds in edible oil by UPLC
Zhongguo youzhi为解决现有检测方法存在前处理净化不完全、不彻底的情况，建立了超高效液相色谱（UPLC）测定食用油中香兰素、甲基香兰素和乙基香兰素含量的分析方法。用乙腈提取食用油中目标物，以乙腈饱和的正己烷萃取净化，冷冻分层后，再经Oasis PRiME HLB固相萃取柱净化，采用C18色谱柱分离，以0.5%甲酸水溶液-乙腈为流动相进行UPLC测定，外标法定量。结果表明：3种香兰素类物质在0.1~100.0 mg/L范围内线性关系良好，相关系数大于0.999，检出限均为0.03 mg/kg，定量限均为0.1 mg/kg ...
孟繁磊，张慧，范宏，谭莉，宋志峰 MENG Fanlei, ZHANG Hui, FAN Hong, TAN Li, SONG Zhifeng
doaj +1 more source
Research on Signal Pickup System for the Wireless Passive LC Resonant Pressure Sensor [PDF]
, 2016 在高温、潮湿等恶劣的环境中以及眼内压测量、疤痕治疗等应用场合，不便利用有线有源的传感器进行压力监测，LC谐振式无线压力传感器采用无线无源方式实现对压力信号的提取，拓展了压力传感器的应用范围。目前，LC谐振式无线压力传感器的信号拾取主要使用网络分析仪或阻抗分析仪，不仅成本高，而且携带不便，极大限制了非实验室场合的应用。本文针对LC谐振式无线MEMS压力传感器的信号拾取现状，从理论分析、系统仿真、硬件设计、软件设计和实验验证等方面展开研究，设计了基于阻抗实部测量法的信号拾取系统。 基于电感耦合理论 ...
蔡建法
core
Using customs data to understand overlooked trade in non‐CITES birds between Africa and Asia
Conservation Biology, EarlyView.Abstract The international trade in live birds poses risks to animals, people, and biodiversity. To effectively mitigate these risks, decision‐makers require information on the volume, dynamics, and direction of trade. Despite Africa once being the largest exporter of birds by region, very little data exist on recent trade in live birds not listed on ...
Alisa Davies +4 more
wiley +1 more source
Fushe yanjiu yu fushe gongyi xuebao为探索绿色、高效降解枸杞中农药残留的方法，提高枸杞产品质量，本研究采用高能电子束辐照的方式处理啶虫脒、吡虫啉、毒死蜱、克百威、炔螨特5种农药污染的枸杞干果样品，利用超高效液相色谱质谱联用法检测辐照前后样品中农药残留的含量，同时探究不同含水率对辐照降解农药的影响。结果表明，当吸收剂量逐渐升高时，5种农药各自的最高降解率在12.9%~41.3%范围内，其中，啶虫脒在8 kGy时，降解率最高，达到41.3%，同一吸收剂量下，枸杞干果中啶虫脒含量越低，其降解率越高。吡虫啉、毒死蜱及克百威在4 ...
朱 捷, 田 珅, 姚 晓瑜, 何 微
doaj +1 more source
Calculation of Young's Modulus and Coefficient of Linear Expansion on Several Solid Solution with Cubic Structure [PDF]
, 2015 杨氏模量和线膨胀系数是表征金属材料重要的物理量。但是，目前已有的二元及多元合金固溶体的杨氏模量和线膨胀系数的实验数据十分有限。因此，利用合理的理论模型来实现对杨氏模量和线膨胀系数的计算并建立性能数据库十分重要，能够为材料设计提供必要的基础信息。本课题组在应用相图计算技术建立热力学数据库和指导合金的成分设计方面取得了不错的成效。本研究基于相图计算的研究方法，考虑温度和成分两个变量的影响，开展合金溶体相的杨氏模量和线膨胀系数的计算。其具体研究成果如下： (1)借鉴计算相图(CALPHAD)方法的研究思路 ...
林明娜
core
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