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811.
基于InGaP/GaAs HBT工艺设计了一款工作频段为2.5~2.7 GHz的高效率低谐波失真的功率放大器.该功放通过在输出匹配网络中引入多个LC谐振网络组合有效抑制了在负载处的高次谐波能量,进而提高了效率.仿真结果表明,该功率放大器在4.5 V的供电电压下,可以在2.5~2.7 GHz工作频率范围内实现37.6 dB的高增益输出,饱和输出功率可达32 dBm以及对应大于36%的功率附加效率(PAE),二次和三次谐波都小于-60 dBc. 相似文献
812.
Anders Smrup Olsen 《Ocean Engineering》2004,31(3-4):401-416
The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use of the potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method. 相似文献
813.
PS剂驱油矿场先导性试验研究 总被引:1,自引:1,他引:1
PS碱木素磺酸盐 (简称 PS剂 )是由造纸废液经浓缩加入酚、醛和硫酸等在高温下复配或反应后提炼出的 1种新型表面活性剂。由于其具有降低原油粘度和油水界面张力的特性[1 -2 ] ,因而可作为提高原油采收率的驱替剂应用到油田开采中。本文通过室内实验和 W31断块的现场驱替试验 ,进一步探讨了 PS剂的驱替机理和驱油效果、探索了注 PS剂驱油的现场经验。 相似文献
814.
815.
816.
none 《The Cartographic journal》2013,50(1):62-67
AbstractThis paper provides a summary of the proceedings and discussion at a conference entitled 'The Future History of Our Landscape', held in October 1992. This meeting explored the issues connected with the changing nature of the Ordnance Survey supply of spatial data, in particular its effect on the Copyright Libraries and their users. Technical and organisational matters concerned with the supply and use of digital data in the archival environment are considered. 相似文献
817.
AEC-Ⅰ型自动排气控制仪(Automatic Exhaust Control)可与真空果配套使用排除水氡观测闪烁室内的残留氡气。该仪器性能稳定、操作简单,能够对闪烁室自动按"排气-抽真空-再排气-再抽真空"顺序循环操作,还可以根据需要调节"排气-抽真空"状态的循环时间,提高排气效率,排气后的闪烁室本底达到《规范》要求,并在面板上实现了排气时间可视化。在该仪器试运行期间,对仪器的稳定性、真空时间和排气时间对排气效果的影响、仪器连续使用时间对排气效果的影响、与手动排气结果对比等方面进行测试分析,结果认为:AEC-I型自动排气控制仪控制精度高,性能稳定,对闪烁室的排气效果达到规范要求,可以作为水氡观测辅助设备用于闪烁室的排气工作。 相似文献
818.
为了正确评价天津宝坻地震台地电阻率的观测效能,调查分析了宝坻地震台地电阻率观测场地和观测系统,统计分析了观测数据的产出和映震效能。结果表明:宝坻地震台地电阻率观测场地、观测系统等基本符合观测规范的要求;观测数据连续、可靠,但精度却有逐年下降的趋势;观测数据对华北北部多个5.0级以上地震和本区及邻近地区多个3.0级以上地震有震前异常反应。宝坻地震台地电阻率观测场地能反映出地震孕育的信息,产出的数据连续、可靠,映震能力较强,但随着城市建设进程的加剧,原良好观测环境有逐渐丧失的可能。 相似文献
819.
This study investigated the effectiveness of a new packing material, namely mixed rice husk silica with dried activated sludge for removing H2S. Dried sewage sludge was collected from Putrajaya sewage treatment plant in Malaysia. Rice husk silica was prepared at temperature of 800°C, after acid leaching and mixed with dried sewage sludge to be utilized in a polyvinyl chloride filter. The system was operated under variable conditions of two parameters, different inlet gas concentration and different inlet flow rate. H2S was passed through the filter with one liter of the packing material. More than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 90–45 s and 300 ppm inlet concentration was observed. However, the RE decreased to 96.87% with the EBRT of 30 s. The maximum elimination capacity (EC) of 52.32 g/m3/h was obtained with the RE of 96.87% and H2S mass loading rate of 54 g/m3/h, while at the RE of 99.96%, maximum EC was 26.99 g/m3/h with the H2S mass‐loading rate of 27 g/m3/h. A strong significant correlation between increasing of H2S mass loading rate and pressure drop was also detected (p < 0.01). Maximum pressure drop was 3.0 mm H2O after 53 days of operating time, the EBRT of 30 s, and 54 g/m3/h of H2S loading rate. These observations suggest that the mixture of rice husk silica with dried activated sludge is a suitable physico‐biological filter for H2S removal. 相似文献
820.
Salem S. Abu Amr Hamidi Abdul Aziz Mohd Nordin Adlan Shuokr Qarani Aziz 《洁净——土壤、空气、水》2013,41(2):148-152
This study investigated the effects of O3 and O3/H2O2/Fe2+ in the advanced oxidation processes (AOPs) on the biodegradable and soluble characteristics of semi‐aerobic stabilized solid waste leachate. The biodegradability (BOD5/chemical oxygen demand, COD) ratio improved from 0.034 to 0.05 and 0.1 following O3 and O3/H2O2/Fe2+, respectively. Fractions of biodegradable COD(bi) (24%), non‐biodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), non‐biodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD(bi) increased to 28 and 36% after applying O3 and O3/AOPs, respectively. COD(S) increased to 59% after O3 and to 72% after O3/AOPs, whereas COD(bsi) increased to 38 and 51% after O3 and O3/AOPs, respectively. The removal efficiency of COD(S) was obtained at 5% after O3 alone and improved to 51% following ozone‐based AOPs, whereas the removal efficiency of PCOD improved from 25% after O3 to 71% after ozone‐based AOPs. 相似文献