This study analyzed data from the DEMETER satellite,collected 10 days before the Wenchuan M_(s)8.0 earthquake on May 12,2008.The time-frequency power spectrum of the data indicated a narrow-band radiative destabilizat...This study analyzed data from the DEMETER satellite,collected 10 days before the Wenchuan M_(s)8.0 earthquake on May 12,2008.The time-frequency power spectrum of the data indicated a narrow-band radiative destabilization(below the cut-off frequency)6 days prior to the earthquake.A signifi cant anomaly in the Ez component was observed 3 days before the event.However,similar phenomena were found over aseismic regions,suggesting a link between ionospheric changes and the earthquake generation process.展开更多
本研究基于2016年对南海三省区的14个沿海主要渔港的连续4个季节抽样调查(共计5256航次,抽样总功率达到89.2×10^4 kW),以kg·kW^-1·d^-1作为CPUE(Catch per unit effort,单位捕捞努力量渔获量)标准化后的单位,对南海9种...本研究基于2016年对南海三省区的14个沿海主要渔港的连续4个季节抽样调查(共计5256航次,抽样总功率达到89.2×10^4 kW),以kg·kW^-1·d^-1作为CPUE(Catch per unit effort,单位捕捞努力量渔获量)标准化后的单位,对南海9种捕捞作业类型渔船的CPUE进行了比较分析。结果显示,CPUE围网>CPUE双拖>CPUE刺网>CPUE罩网>CPUE张网>CPUE单拖>CPUE虾拖>CPUE笼壶>CPUE钓具。不同捕捞作业类型CPUE随渔船功率段的变化而不同,CPUE峰值数及其所对应的最优功率段(渔获率最高的功率段)也有差异,单拖和虾拖渔船的CPUE随渔船功率的变化具有1个CPUE峰值点,最优功率段分别为(200~250)kW(CPUE=8.6 kg·kW^-1·d^-1)和(150~200)kW(CPUE=5.0 kg·kW^-1·d^-1);围网、双拖、钓具和刺网渔船的CPUE随渔船功率的变化有2个CPUE峰值点,对应的最优功率段分别为(200~250)kW(CPUE=47.7 kg·kW^-1·d^-1)、(350~400)kW(CPUE=16.8kg·kW^-1·d^-1)、(50~100)(CPUE=2.9kg·kW^-1·d^-1)和(0~50)kW(CPUE=6.9 kg·kW^-1·d^-1)。罩网渔船CPUE随功率段变化有3个峰值点,最优功率段为(0~50)kW(CPUE=7.0kg·kW^-1·d^-1)。不同捕捞作业类型CPUE季节变化表现:围网CPUE均值在春季最高,单拖、双拖、罩网、钓具和笼壶在夏季最高,张网在秋季最高,刺网和虾拖在冬季最高。展开更多
作为中国挖掘机行业动力主要供应商,洋马发动机在bauma China 2014中是不折不扣的明星,其展品不但有满足当前排放法规的Tier2产品以及即将到来的Tier3产品,更是包括多款能够满足Tier4的发动机。III阶段排放标准实施在即,洋马准备好了吗...作为中国挖掘机行业动力主要供应商,洋马发动机在bauma China 2014中是不折不扣的明星,其展品不但有满足当前排放法规的Tier2产品以及即将到来的Tier3产品,更是包括多款能够满足Tier4的发动机。III阶段排放标准实施在即,洋马准备好了吗？挖掘机厂家准备好了吗？如何应对？发展趋势如何？带着这些问题,本刊记者采访了洋马发动机（上海）有限公司小型陆用柴油机部部长德留尚之先生。展开更多
The performance of a microwave monolithic integrated circuit .（MMIC） amplifier with high output power in the Ka-band is presented. Using 75mm 0.25μm GaAs PHEMT technology provided by the Hebei Semiconductor Researc...The performance of a microwave monolithic integrated circuit .（MMIC） amplifier with high output power in the Ka-band is presented. Using 75mm 0.25μm GaAs PHEMT technology provided by the Hebei Semiconductor Research Institute, this three-stage power amplifier, with a chip size of 19.25mm^2 （3.5mm × 5.5mm）, on 100μm GaAs substrate achieves a linear gain of more than 16dB in the 32.5-35.5GHz frequency range,with an average output power at 1dB gain compression of P1dB = 29. 8dBm and a maximum saturated output power of Psat = 31dBm.展开更多
基金National Natural Science Foundation of China(No.41274079,No.42304080)Seismic Safety and Health Monitoring of Major Construction Projects-Bridge and Reservoir Seismic Monitoring(No.DZ2024083000001)State Key Research and Development Plan under Grant(No.2018YFE0208300,No.2018YFC0603500).
文摘This study analyzed data from the DEMETER satellite,collected 10 days before the Wenchuan M_(s)8.0 earthquake on May 12,2008.The time-frequency power spectrum of the data indicated a narrow-band radiative destabilization(below the cut-off frequency)6 days prior to the earthquake.A signifi cant anomaly in the Ez component was observed 3 days before the event.However,similar phenomena were found over aseismic regions,suggesting a link between ionospheric changes and the earthquake generation process.
文摘本研究基于2016年对南海三省区的14个沿海主要渔港的连续4个季节抽样调查(共计5256航次,抽样总功率达到89.2×10^4 kW),以kg·kW^-1·d^-1作为CPUE(Catch per unit effort,单位捕捞努力量渔获量)标准化后的单位,对南海9种捕捞作业类型渔船的CPUE进行了比较分析。结果显示,CPUE围网>CPUE双拖>CPUE刺网>CPUE罩网>CPUE张网>CPUE单拖>CPUE虾拖>CPUE笼壶>CPUE钓具。不同捕捞作业类型CPUE随渔船功率段的变化而不同,CPUE峰值数及其所对应的最优功率段(渔获率最高的功率段)也有差异,单拖和虾拖渔船的CPUE随渔船功率的变化具有1个CPUE峰值点,最优功率段分别为(200~250)kW(CPUE=8.6 kg·kW^-1·d^-1)和(150~200)kW(CPUE=5.0 kg·kW^-1·d^-1);围网、双拖、钓具和刺网渔船的CPUE随渔船功率的变化有2个CPUE峰值点,对应的最优功率段分别为(200~250)kW(CPUE=47.7 kg·kW^-1·d^-1)、(350~400)kW(CPUE=16.8kg·kW^-1·d^-1)、(50~100)(CPUE=2.9kg·kW^-1·d^-1)和(0~50)kW(CPUE=6.9 kg·kW^-1·d^-1)。罩网渔船CPUE随功率段变化有3个峰值点,最优功率段为(0~50)kW(CPUE=7.0kg·kW^-1·d^-1)。不同捕捞作业类型CPUE季节变化表现:围网CPUE均值在春季最高,单拖、双拖、罩网、钓具和笼壶在夏季最高,张网在秋季最高,刺网和虾拖在冬季最高。
文摘作为中国挖掘机行业动力主要供应商,洋马发动机在bauma China 2014中是不折不扣的明星,其展品不但有满足当前排放法规的Tier2产品以及即将到来的Tier3产品,更是包括多款能够满足Tier4的发动机。III阶段排放标准实施在即,洋马准备好了吗？挖掘机厂家准备好了吗？如何应对？发展趋势如何？带着这些问题,本刊记者采访了洋马发动机（上海）有限公司小型陆用柴油机部部长德留尚之先生。
文摘The performance of a microwave monolithic integrated circuit .（MMIC） amplifier with high output power in the Ka-band is presented. Using 75mm 0.25μm GaAs PHEMT technology provided by the Hebei Semiconductor Research Institute, this three-stage power amplifier, with a chip size of 19.25mm^2 （3.5mm × 5.5mm）, on 100μm GaAs substrate achieves a linear gain of more than 16dB in the 32.5-35.5GHz frequency range,with an average output power at 1dB gain compression of P1dB = 29. 8dBm and a maximum saturated output power of Psat = 31dBm.
