Results 31 to 40 of about 997,974 (152)
Gaoya dianqi, 1999 设计制作了用于研究臭氧合成的小型高频电源,能产生多种频率的高频高压,幅值从0至10kV可调.对沿面放电电极结构初步研究了高频电压下臭氧的合成.
丁卫东 +3 more
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World Water Policy, Volume 12, Issue 4, November 2026.ABSTRACT Biochemical oxygen demand (BOD) remains a core indicator of organic pollution in freshwater monitoring, but its role in water policy and practice is changing as water‐quality assessment moves toward predictive, integrative, and decision‐support approaches.
Isadora Favero Roque Cenci +5 more
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, 2016 本文以高强钢GCr15为例,通过不同的热处理工艺得到拉伸强度分别为2214MPa和1588 MPa的试样,研究加载频率对超高周疲劳行为的影响。通过旋转弯曲疲劳试验机、高频疲劳试验机和超声疲劳试验机分别对试样施加52.5 Hz、130 Hz和20 k Hz的加载频率。两种试样在三种加载频率下的S-N曲线呈现出不同的频率效应。对于1588 MPa试样,20 kHz下的疲劳强度和寿命明显高于52.5 Hz和130Hz的疲劳强度和寿命(I型频率效应);对于2214 MPa试样,20 k ...
胡远培, 洪友士
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Gaoya dianqi, 2005 研制了宽带和窄带两种超高频外置天线传感器,两种传感器增益均大于1,驻波比在其有效带宽范围内均小于2,均能用于GIS局部放电超高频检测。设计了高性能放大器和半分布参数超高频滤波器,工作频带为300～1000MHz,完全覆盖了两种传感器的工作频带。性能测试表明,传感器和滤波放大器性能优良,频率匹配,能满足超高频信号检测预处理的要求。通过对绝缘子表面金属污染缺陷产生的局部放电信号进行检测研究表明,超高频检测系统能够检测到超高频段微弱的局部放电信号,并能抑制低频段干扰,为后续模式识别的研究打下了基础。
唐炬 +4 more
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Dianci bileiqi, 2021 为准确获取不同温度条件下胶浸纸套管绝缘性能变化规律,在高低温试验箱中开展了±100 kV穿墙套管在不同温度下的频域介电谱测试,获得了被测试套管的绝缘电阻、工频介损、工频电容量等绝缘特征参数。研究结果表明:胶浸纸套管各绝缘性能参量对温度变化的反应较为敏感,工频介损因数随温度的上升呈现先减小后逐渐增加的趋势;绝缘电阻随温度的升高逐渐减小,且减小幅度较大;在低频区域,胶浸纸套管的介损随温度的升高逐渐增大,高频区域相反,介损频域谱随温度的升高整体向高频方向移动;胶浸纸套管的复电容实部在高频段基本保持不变,C ...
张寒 +5 more
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Predictive evolutionary genomics: principles, validation, and practice
New Phytologist, Volume 252, Issue 1, Page 36-48, October 2026.Summary Climate change and habitat loss are driving rapid evolutionary responses in populations world‐wide, which creates an urgent need for evolutionary forecasting in conservation and agriculture. Such forecasting can be categorized into three time scales: trait‐based models that use multivariate quantitative genetic equations to project correlated ...
Daniel Ortiz‐Barrientos +5 more
wiley +1 more source
四川大学学报. 自然科学版, 2015 为了解决低分辨率遥感图像超分辨重建的问题,本文提出了一种基于双重字典及联合特征的遥感图像超分辨率算法.超分辨率重建技术目的就是根据低分辨率图像重建出原始高分辨率图像的高频信息.本文将图像的高频信息分解成为主高频信息和残差高频信息两个部分,然后针对主高频信息和残差高频信息,分别训练主高频字典和残差高频字典,并结合稀疏表示方法对图像进行重构.同时,为了建立更能反映图像内部结构信息的字典,本文联合图像的不同的结构特征,建立统一的字典.本文算法对图像取得较好的复原效果,复原出的高分辨率图像更接近于真实图像 ...
杨晓敏, 吴炜, 严斌宇, 张莹莹
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Neutral interactions among non‐native plants are common
New Phytologist, Volume 252, Issue 1, Page 292-309, October 2026.Global distribution of studies and overall effect of co‐invasion for all metrics of non‐native plant performance combined. Summary Globalization has accelerated the establishment of non‐native plant species, increasing the prevalence of multispecies co‐invasions; yet interactions among co‐invaders remain poorly understood.
Feng He +7 more
wiley +1 more source
Functional Ecology, Volume 40, Issue 9, Page 2843-2860, September 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Drylands are mainly structured by both vascular plants and biological soil crusts (biocrusts), the latter often regarded as a self‐organizing component of these ecosystems.
Haoran Luo +13 more
wiley +1 more source
Dianci bileiqi, 2023 为研究温度对环氧胶浸纸绝缘套管频域介电响应特性的影响，开展了环氧胶浸纸绝缘样片在高低温(10℃～120℃)循环下的频域介电谱测试，绘制了不同循环次数下环氧胶浸纸绝缘样片的频域介电响应特性曲线。结果表明：随着高低温循环次数的增加，在120℃时介质损耗因数、复合电容实部和虚部频谱曲线整体向上和高频方向移动，在10℃时在高频区域下介质损耗因数和复合电容虚部的频谱曲线整体向上移动，而复合电容实部的频谱曲线基本保持不变。10℃和120 ...
翟春雨 +6 more
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