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石蒜叶片微弱电波动信号的测定 被引量:18
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作者 王兰州 曹文侠 +1 位作者 令利军 程昉 《西北师范大学学报(自然科学版)》 CAS 2000年第2期62-66,共5页
采用金属电极测定了石蒜叶片的微弱电波信号 .石蒜植物叶片微弱低频电波信号的变化区间是 4~ 30 μV ,其低频信号随叶片基部向先端延伸而减弱 ,这种微弱信号随着植物叶片在空间的分布可构成叶片等电势线 .石蒜叶片微弱电波动信号具有... 采用金属电极测定了石蒜叶片的微弱电波信号 .石蒜植物叶片微弱低频电波信号的变化区间是 4~ 30 μV ,其低频信号随叶片基部向先端延伸而减弱 ,这种微弱信号随着植物叶片在空间的分布可构成叶片等电势线 .石蒜叶片微弱电波动信号具有从基部向上的生理向性 . 展开更多
关键词 石蒜 生理向性 叶片 微弱电波动信号 测定
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Acacia mearnsii management in a South African National Parks:SWOT analysis using hot topics in biological invasion as a guide 被引量:1
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作者 Geoffrey MUKWADA Desmond MANATSA 《Journal of Mountain Science》 SCIE CSCD 2017年第1期205-218,共14页
The assessment of the policy framework governing Invasive Alien Species(IAS) control is of critical importance in conservation. The undertaking of a SWOT analysis of such a framework is necessary because it enhances t... The assessment of the policy framework governing Invasive Alien Species(IAS) control is of critical importance in conservation. The undertaking of a SWOT analysis of such a framework is necessary because it enhances the efficacy of IAS control. The aim of this study is to carry out a SWOT analysis of the policy framework guiding the control of the spreading of Acacia mearnsii and other IAS in the Golden Gate Highlands National Park in South Africa,as well as the implementation of restorative measures in the park and adjacent communities in line with the recommendations of the Convention on Biodiversity. A comparative analysis of this framework and the hierarchical framework that was developed during the European Union Conference on Freshwater Invasives- Networking for Strategy in 2013 is undertaken. The results indicate the need to strengthen parkcommunity relations,upgrade existing legislation,and boost the technical capacity of South African national parks to identify,detect,monitor and predict IAS invasions,both within the parks and their surroundings. This knowledge is important for developing future policies on IAS control in South Africa. 展开更多
关键词 Convention on biodiversity Geographic Information Systems Golden Gate Highlands National Park Invasive alien species MalutiDrakensberg Mountains Protected Areas Policy Framework SWOT
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Revealing the Invisible: A New Approach for Enhancing Industrial Safety, Reliability and Remaining Life Assessment
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作者 Isaac Einav Boris Artemiev Sergey Zhukov 《Journal of Chemistry and Chemical Engineering》 2015年第3期191-198,共8页
Today's industry requires more reliable information on the current status of their hard assets; prognosis for continued usability of systems and better predictability of equipment life cycle maintenance. Therefore, a... Today's industry requires more reliable information on the current status of their hard assets; prognosis for continued usability of systems and better predictability of equipment life cycle maintenance. Therefore, an innovative technique for early detection of potential failure and condition monitoring is urgently required by many engineers. This document describes a novel approach to improve industrial equipment safety, reliability and life cycle management. A new field portable instrument called the "IMS (indicator of mechanical stresses)" utilizes magneto-anisotropic ("cross") transducers to measure anisotropy of magnetic properties in ferromagnetic material. Mechanical stresses including residual stresses in Ferro-magnetic parts, are "not visible" to most traditional NDT (non-destructive testing) methods; for example, radiography and ultrasonic inspection. Stress build-up can be the first indicator that something is faulty with a structure. This can be the result of a manufacturing defect; or as assets age and fatigue, stress loads can become unevenly distributed throughout the metal. We outline the evaluation of IMS as a fast screening tool to provide structural condition or deterioration feedback in novel applications for pipelines, petrochemical refinery, cranes, and municipal infrastructure. 展开更多
关键词 IMS mechanical stress concentration mechanical stress gradient stress detection and classification.
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Integral Equation Method for Electromagnetic Wave Propagation in Stratified Anisotropic Dielectric-Magnetic Materials
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作者 舒维星 付娜 +3 位作者 吕小方 罗海陆 文双春 范滇元 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第11期879-885,共7页
We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materialsusing the integral equation method (IEM).Based on the superposition principle, we use Hertz vector formula... We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materialsusing the integral equation method (IEM).Based on the superposition principle, we use Hertz vector formulations ofradiated fields to study the interaction of wave with matter.We derive in a new way the dispersion relation, Snell's lawand reflection/transmission coefficients by self-consistent analyses.Moreover, we find two new forms of the generalizedextinction theorem.Applying the IEM, we investigate the wave propagation through a slab and disclose the underlyingphysics, which are further verified by numerical simulations.The results lead to a unified framework of the IEM for thepropagation of wave incident either from a medium or vacuum in stratified dielectric-magnetic materials. 展开更多
关键词 integral equation stratified dielectric-magnetic materials extinction theorem METAMATERIALS
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