The frequency–space（f–x） empirical mode decomposition（EMD） denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function（IMF） results in ...The frequency–space（f–x） empirical mode decomposition（EMD） denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function（IMF） results in signal damage and limited denoising. Second, decomposing the real and imaginary parts of complex data may lead to inconsistent decomposition numbers. Thus, we propose a new method named f–x spatial projection-based complex empirical mode decomposition（CEMD） prediction filtering. The proposed approach directly decomposes complex seismic data into a series of complex IMFs（CIMFs） using the spatial projection-based CEMD algorithm and then applies f–x predictive filtering to the stationary CIMFs to improve the signal-to-noise ratio. Synthetic and real data examples were used to demonstrate the performance of the new method in random noise attenuation and seismic signal preservation.展开更多
Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectros...Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectroscopic techniques.In vitro,compounds 1 and 2 were found to show signifcant cytotoxic activity against selected cancer cells,including P-388,HONE-1 and HT-29.展开更多
KVPO_(4)F(KVPF)has been extensively investigated as the potential cathode material for potassium-ion batteries(PIBs)owing to its high theoretical capacity,superior operating voltage,and three-dimensional Kt conduction...KVPO_(4)F(KVPF)has been extensively investigated as the potential cathode material for potassium-ion batteries(PIBs)owing to its high theoretical capacity,superior operating voltage,and three-dimensional Kt conduction pathway.Nevertheless,the electrochemical behavior of KVPF is limited by the inherent poor electronic conductivity of the phosphate framework and unstable electrode/electrolyte interface.To address the above issues,this work proposes an infiltration-calcination method to confine the in-situ grown KVPF into the mesoporous carbon CMK-3(denoted KVPF@CMK-3).The assembled KVPF@CMK-3 nanocomposite features three-dimensional interconnected carbon channels,which not only offer abundant active sites and significantly accelerate K t/electron transport,but also prevent the growth of KVPF nanoparticle agglomerates,hence stabilizing the structure of the material.Additionally,V–F–C bonds are created at the interface of KVPF and CMK-3,which reduce the loss of F and stabilize the electrode interface.Thus,when tested as a cathode material for PIBs,the KVPF@CMK-3 nanocomposite delivers superior reversible capacitiy(103.2 mAh g^(-1) at 0.2 C),outstanding rate performance(90.1 mAh g^(-1) at 20 C),and steady cycling performance(92.2 mAh g^(-1) at 10 C and with the retention of 88.2%after 500 cycles).Moreover,its potassium storage mechanism is further examined by ex-situ XRD and ex-situ XPS techniques.The above synthetic strategy demonstrates the potential of KVPF@CMK-3 to be applied as the cathode for PIBs.展开更多
为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数...为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数据划分成信号帧和噪声帧,采用3F–C法估计了白噪声和窄带干扰参数。通过仿真实验和实测数据处理,与传统小波包降噪方法的结果进行了对比。数据分析结果表明:无论是针对单一白噪声环境还是存在窄带干扰的混合噪声环境,该能量估计方法的准确性均优于传统小波包降噪方法,且随着信噪比的降低和信号时间窗口长度的增加,该方法表现出更明显的优势。在信噪比为–8 d B的条件下,使用该方法对实测局部放电脉冲信号进行能量估计的相对误差仅为4.07%,而使用小波包降噪方法时相对误差则达到44.12%。展开更多
F–Fe/TiO_2 composite photocatalyst was synthesized by a facile one-step hydrothermal method and then characterized by XRD, XPS and UV–Vis DRS. The catalyst of F–Fe/TiO_2 exhibited the highest photodegradation rate ...F–Fe/TiO_2 composite photocatalyst was synthesized by a facile one-step hydrothermal method and then characterized by XRD, XPS and UV–Vis DRS. The catalyst of F–Fe/TiO_2 exhibited the highest photodegradation rate for phenol as compared with pure TiO_2, F/TiO_2, Fe/TiO_2, F0.38–Fe0.13–TiO_2 and Fe(III)/F-TiO_2 under visible light irradiation. The simulated conditions of industrial phenolic wastewater including initial phenol concentration,visible light intensity, p H and different anions were investigated in the presence of F–Fe/TiO_2 photocatalyst. In addition, as expected, the F–Fe/TiO_2 photocatalyst displayed excellent stability, showing a potential industrial application for the treatment of phenolic wastewater.展开更多
Computations for air gap response of a semisubmersible platform based on a 3D numerical wave tank approach are presented.The developed method is in time domain and can consider nonlinearities associated with incident ...Computations for air gap response of a semisubmersible platform based on a 3D numerical wave tank approach are presented.The developed method is in time domain and can consider nonlinearities associated with incident wave and hydrostatic forces exactly in determining the body response, but the interaction hydrodynamics of radiation and diffraction are based on simplified linearization assumptions. The incident wave can be defined by any suitable wave theory and here defined by a fully nonlinear numerical wave model. After verifying the present computations results in its degenerated linearized version against the usual linear 3D Green function–based frequency-domain results for air gap predictions, systematic comparative studies are undertaken between linear and the approximate nonlinear solutions. It is found that nonlinear computations can yield considerably conservative predictions as compared to fully linear calculations, amounting to a difference of up to 30%–40% in the minimum air gap in steep ambient incident waves at high and moderate frequencies.展开更多
提出一种由不同厚度和不同面积的多层介质板叠加制作多层介质覆盖层,代替传统单层介质覆盖层,提高Fabry-Perot(F–P)谐振腔天线增益和口径效率的设计方法。以工作频点5.8 GHz的F–P谐振腔天线设计为例,采用微带贴片天线作为馈源,由多层...提出一种由不同厚度和不同面积的多层介质板叠加制作多层介质覆盖层,代替传统单层介质覆盖层,提高Fabry-Perot(F–P)谐振腔天线增益和口径效率的设计方法。以工作频点5.8 GHz的F–P谐振腔天线设计为例,采用微带贴片天线作为馈源,由多层厚度分别为1 mm,1 mm和1.5 mm,直径分别为160 mm,130 mm和120 mm,相对介电常数为16的聚四氟乙烯介质板叠加制作该天线覆盖层。天线样品的测试结果与设计仿真结果吻合良好。与传统单层介质覆盖层相比,该多层介质覆盖层将工作频率5.8 GHz处天线增益由18.2 d Bi提高到19.1 d Bi,相应口径效率由70.02%增加到86.14%,天线|S_(11)|<-10 d B阻抗带宽和3 d B增益带宽略有提高,分别达到8.19%和11.90%。展开更多
基金supported financially by the National Natural Science Foundation(No.41174117)the Major National Science and Technology Projects(No.2011ZX05031–001)
文摘The frequency–space（f–x） empirical mode decomposition（EMD） denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function（IMF） results in signal damage and limited denoising. Second, decomposing the real and imaginary parts of complex data may lead to inconsistent decomposition numbers. Thus, we propose a new method named f–x spatial projection-based complex empirical mode decomposition（CEMD） prediction filtering. The proposed approach directly decomposes complex seismic data into a series of complex IMFs（CIMFs） using the spatial projection-based CEMD algorithm and then applies f–x predictive filtering to the stationary CIMFs to improve the signal-to-noise ratio. Synthetic and real data examples were used to demonstrate the performance of the new method in random noise attenuation and seismic signal preservation.
基金financially supported by the Natural Science Foundation of Shandong Province (No. ZR2009CZ004)
文摘Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectroscopic techniques.In vitro,compounds 1 and 2 were found to show signifcant cytotoxic activity against selected cancer cells,including P-388,HONE-1 and HT-29.
基金This work was supported by the National Natural Science Foundation of China(22179063).
文摘KVPO_(4)F(KVPF)has been extensively investigated as the potential cathode material for potassium-ion batteries(PIBs)owing to its high theoretical capacity,superior operating voltage,and three-dimensional Kt conduction pathway.Nevertheless,the electrochemical behavior of KVPF is limited by the inherent poor electronic conductivity of the phosphate framework and unstable electrode/electrolyte interface.To address the above issues,this work proposes an infiltration-calcination method to confine the in-situ grown KVPF into the mesoporous carbon CMK-3(denoted KVPF@CMK-3).The assembled KVPF@CMK-3 nanocomposite features three-dimensional interconnected carbon channels,which not only offer abundant active sites and significantly accelerate K t/electron transport,but also prevent the growth of KVPF nanoparticle agglomerates,hence stabilizing the structure of the material.Additionally,V–F–C bonds are created at the interface of KVPF and CMK-3,which reduce the loss of F and stabilize the electrode interface.Thus,when tested as a cathode material for PIBs,the KVPF@CMK-3 nanocomposite delivers superior reversible capacitiy(103.2 mAh g^(-1) at 0.2 C),outstanding rate performance(90.1 mAh g^(-1) at 20 C),and steady cycling performance(92.2 mAh g^(-1) at 10 C and with the retention of 88.2%after 500 cycles).Moreover,its potassium storage mechanism is further examined by ex-situ XRD and ex-situ XPS techniques.The above synthetic strategy demonstrates the potential of KVPF@CMK-3 to be applied as the cathode for PIBs.
文摘为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数据划分成信号帧和噪声帧,采用3F–C法估计了白噪声和窄带干扰参数。通过仿真实验和实测数据处理,与传统小波包降噪方法的结果进行了对比。数据分析结果表明:无论是针对单一白噪声环境还是存在窄带干扰的混合噪声环境,该能量估计方法的准确性均优于传统小波包降噪方法,且随着信噪比的降低和信号时间窗口长度的增加,该方法表现出更明显的优势。在信噪比为–8 d B的条件下,使用该方法对实测局部放电脉冲信号进行能量估计的相对误差仅为4.07%,而使用小波包降噪方法时相对误差则达到44.12%。
基金Supported by the National Natural Science Foundations of China(Nos.21276125,21476108,20876077)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘F–Fe/TiO_2 composite photocatalyst was synthesized by a facile one-step hydrothermal method and then characterized by XRD, XPS and UV–Vis DRS. The catalyst of F–Fe/TiO_2 exhibited the highest photodegradation rate for phenol as compared with pure TiO_2, F/TiO_2, Fe/TiO_2, F0.38–Fe0.13–TiO_2 and Fe(III)/F-TiO_2 under visible light irradiation. The simulated conditions of industrial phenolic wastewater including initial phenol concentration,visible light intensity, p H and different anions were investigated in the presence of F–Fe/TiO_2 photocatalyst. In addition, as expected, the F–Fe/TiO_2 photocatalyst displayed excellent stability, showing a potential industrial application for the treatment of phenolic wastewater.
文摘Computations for air gap response of a semisubmersible platform based on a 3D numerical wave tank approach are presented.The developed method is in time domain and can consider nonlinearities associated with incident wave and hydrostatic forces exactly in determining the body response, but the interaction hydrodynamics of radiation and diffraction are based on simplified linearization assumptions. The incident wave can be defined by any suitable wave theory and here defined by a fully nonlinear numerical wave model. After verifying the present computations results in its degenerated linearized version against the usual linear 3D Green function–based frequency-domain results for air gap predictions, systematic comparative studies are undertaken between linear and the approximate nonlinear solutions. It is found that nonlinear computations can yield considerably conservative predictions as compared to fully linear calculations, amounting to a difference of up to 30%–40% in the minimum air gap in steep ambient incident waves at high and moderate frequencies.
文摘提出一种由不同厚度和不同面积的多层介质板叠加制作多层介质覆盖层,代替传统单层介质覆盖层,提高Fabry-Perot(F–P)谐振腔天线增益和口径效率的设计方法。以工作频点5.8 GHz的F–P谐振腔天线设计为例,采用微带贴片天线作为馈源,由多层厚度分别为1 mm,1 mm和1.5 mm,直径分别为160 mm,130 mm和120 mm,相对介电常数为16的聚四氟乙烯介质板叠加制作该天线覆盖层。天线样品的测试结果与设计仿真结果吻合良好。与传统单层介质覆盖层相比,该多层介质覆盖层将工作频率5.8 GHz处天线增益由18.2 d Bi提高到19.1 d Bi,相应口径效率由70.02%增加到86.14%,天线|S_(11)|<-10 d B阻抗带宽和3 d B增益带宽略有提高,分别达到8.19%和11.90%。
