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排序方式: 共有78条查询结果,搜索用时 15 毫秒
1.
实现了一种可重构振荡器与双频率滤波器的协同设计模块。振荡器通过开关二极管的通断来实现频率的可重构,工作频率分别为1.1 GHz和2.0 GHz。与双频滤波器协同设计后,振荡器在两个频率上频偏1 MHz的相位噪声分别从-109.1 dBc/Hz和-112.9 dBc/Hz改善为-125.6 dBc/Hz和-127.9 dBc/Hz,二次谐波抑制分别由协同设计之前的-25 dB和-10 dB改善为-44 dB和-55 dB。 相似文献
2.
Benoit Igne Jean-Michel Roger Sylvie Roussel Vronique Bellon-Maurel Charles R. Hurburgh 《Chemometrics and Intelligent Laboratory Systems》2009,99(1):57-65
Eight calibration transfer methods based on the removal of orthogonal signal were compared for the standardization of whole soybean protein and oil models. Dynamic orthogonal projection (DOP), transfer by orthogonal projection (TOP), error removal by orthogonal subtraction (EROS), orthogonal signal correction (OSC), and orthogonal projections to latent structures (O-PLS) as well as the modification and extension of some of these methods were compared in the transfer of models in intra and inter-brand situations using two Foss Infratecs and two Bruins OmegAnalyzerGs. For each brand, a master was designated and its models transferred onto the second unit of its network and the two units of the second brand. Calibration models were transferable from brand to brand with similar or better precision than when each instrument was calibrated on its own calibration set (for Infratec 1229, the relative predictive determinant (RPD) increased in intra and inter-brand calibration transfer situations from 10.42 to 11.45 and 10.57, with DOP and EROS respectively). Performance of each method was different across parameters, instruments, and validation sets. DOP modifications on the determination of the difference matrix showed promising results while TOP and EROS extensions to include variability specifically present in certain crop years did not bring any beneficial effects. 相似文献
3.
CeO2-ZrO2-MnOx mixed oxide series were prepared by sol-gel method. CO pulse and CO-O2 cycle measurements were carried out to examine the oxygen storage complete capacity (OSCC) and dynamic oxygen storage capacity (OSC) of the samples. The doping method brought about strong interactions between manganese oxide and ceria, both in the bulk and on the surface. Only a small part of Mn cations are incorporated into the ceria lattice to form solid solutions and the remaining are left on the surface as finely dispersed Mn3O4. The OSC behaviors of the materials are influenced by the doping amount of Mn and the solubility of Mn in the CeO2 lattice. The OSC is more easily affected by available contents of oxygen storage components when the measurement frequency is low. Comparatively, the concentration of lattice defects, which affects the mobility of bulk oxygen, is the determining factor under high frequency. 相似文献
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《中国稀土学报(英文版)》2020,38(3):274-280
Cerium zirconium-based(CZ) oxygen storage materials(OSMs) play a crucial role in three-way catalysts(TWCs),while CZ needs to be modified to satisfy more rigorous emission standard.In this study,transition metal(TMs=Mn,Cr,Fe,Cu) oxides modified CZ were prepared by incipient wetness impregnation method to improve the oxygen storage capacity of CZ-based materials.To clearly illustrate the influence of TM oxides,N_2 adsorption-desorption,X-ray diffraction(XRD),oxygen storage capacity(OSC),temperature programmed reduction by H_2(H_2-TPR) and X-ray photoelectron spectroscopy(XPS) were used to characterize the physical and chemical properties of samples.It is found that,all modified CZ have higher OSC,lower reduction temperatures than those of pristine CZ.Interaction between TMOs and CZ take precedence over specific surface to influence OSC.Notably,FeO_x/CZ has the highest OSC,which is about 1.9 times that of CZ and it could be attributed to synergistic effect between FeO_x and CZ;CuO_x/CZ has the lowest reduction temperature which is 168℃lower than that of CZ,and it can be explained by hydrogen spillover effect. 相似文献
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Two thermal stable phases, Ce0.75Zr0.25O2 and Ce0.16Zr0.84O2, with different surface area were prepared by coprecipitation. The oxygen storage capacity (OSC) measurements were carried
out at 500 °C under both transient (CO–O2 cycle at 0.05, 0.1 and 0.25 Hz) and stationary reaction conditions (CO pulse). In the oxygen storage/release process, the
rate-determine step is surface reactions when the specific surface area is lower than 60 m2/g. When the surface area increases further, the influence of surface area is less important. The increased surface area favors
diesel soot catalytic combustion via providing more redox sites to activate adsorbed oxygen. Nevertheless, this effect is
less important when the specific surface area is larger than 40 m2/g, especially under loose contact condition. 相似文献
10.
催化转换器在线诊断功能标定 总被引:2,自引:0,他引:2
针对国家标准GB 18352.3-2005的要求,在传统的利用三元催化转换器储氧能力进行OBD诊断方法的基础上,开发出一种新的三元催化转换器OBD诊断数值算法。使用此数值算法对捷达1.6轿车进行车载诊断OBD系统标定。试验结果表明,三元催化转换器的诊断结果完全满足国家标准要求,对排放结果没有影响。 相似文献