A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and ...A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar system.However,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space targets.To be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization inevitably.To solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this paper.First,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are analyzed.Then,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space targets.Thereafter,the RCM and DFM are corrected by the compensation function correlated with the estimated motion parameters.Finally,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo signal.Numerical simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection.展开更多
目的从生物信息学角度了解空肠弯曲菌主要外膜蛋白OMP18的跨膜结构、B细胞抗原表位及其抗原性、基因序列保守性等特征,并鉴定空肠弯曲菌主要外膜蛋白优势B细胞抗原表位,为后续抗体检测和疫苗研究提供实验依据。方法使用NCBI/Blast,TMHMM...目的从生物信息学角度了解空肠弯曲菌主要外膜蛋白OMP18的跨膜结构、B细胞抗原表位及其抗原性、基因序列保守性等特征,并鉴定空肠弯曲菌主要外膜蛋白优势B细胞抗原表位,为后续抗体检测和疫苗研究提供实验依据。方法使用NCBI/Blast,TMHMM Server V2.0,DNA Star等生物信息学分析软件对空肠弯曲菌主要外膜蛋白OMP18进行蛋白跨膜结构预测、线性B细胞抗原表位及其抗原性分析、并对不同空肠弯曲菌OMP18蛋白的氨基酸序列同源性进行比较。采用空肠弯曲菌全菌抗体IgG为一抗,基于ELISA技术对优势线性B细胞抗原表位进行筛选鉴定。结果生物信息学预测结果表明外膜蛋白OMP18定位于空肠弯曲菌外膜且不存在跨膜结构。蛋白序列保守存在于各空肠弯曲菌株中,序列同源性达95%以上。同时,我们发现该外膜蛋白中存在3个明显的B细胞线性表位,且具有很强的抗原性。ELISA检测鉴定结果表明3个B细胞抗原表位都能有效识别空肠弯曲菌全菌抗体。结论空肠弯曲菌主要外膜蛋白OMP18保守存在于细菌表面,存在3个重要的B细胞线性抗原表位,可用于后续的抗体检测和疫苗开发研究。展开更多
In this paper,in order to reduce the energy leakage caused by the discretized representation in sparse channel estimation for Orthogonal Frequency Division Multiplexing(OFDM)systems,we systematically have analyzed the...In this paper,in order to reduce the energy leakage caused by the discretized representation in sparse channel estimation for Orthogonal Frequency Division Multiplexing(OFDM)systems,we systematically have analyzed the optimal locations of atoms with discrete delays for each path reconstruction from the perspective of linear fitting theory.Then,we have investigated the adverse effects of the non-ideal inner product function on the iteration in one of the most widely used channel estimation method,Orthogonal Matching Pursuit(OMP).The study shows that the distance between the selected atoms for each path in OMP can be larger than the sampling interval,which prevents OMP-based methods from achieving better performance.To overcome this drawback,the image deblurring-based channel estimation method,in which the channel estimation problem is analogized to one-dimensional image deblurring,was proposed to improve the large compensation distance of traditional OMP.The advantage of the proposed method was validated by the results of numerical simulation and sea trial data decoding.展开更多
目的通过观察苗药头花蓼作用前后的幽门螺杆菌(Helicobacter pylori,H.pylori)外膜蛋白(outer membrane protein,omp)及omp8、omp32基因表达水平的变化,探讨头花蓼抑制H.pylori生长活性的机制。方法应用Western blot及Real time PCR技...目的通过观察苗药头花蓼作用前后的幽门螺杆菌(Helicobacter pylori,H.pylori)外膜蛋白(outer membrane protein,omp)及omp8、omp32基因表达水平的变化,探讨头花蓼抑制H.pylori生长活性的机制。方法应用Western blot及Real time PCR技术检测苗药头花蓼作用前后,H.pylori外膜蛋白及omp8、omp32 mRNA表达量的变化。结果 Western blot结果显示,苗药头花蓼作用后omp较对照组升高,具有统计学差异(P<0.05);Real time PCR结果显示,H.pylori在苗药头花蓼作用后其omp8、omp32 mRNA表达量分别较对照组上调2.339倍和2.597倍,具有统计学意义(P<0.05)。结论苗药头花蓼通过上调H.pylori外膜蛋白及omp8、omp32 mRNA水平,引起外膜通透性改变,从而发挥抗菌作用。展开更多
文摘A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar system.However,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space targets.To be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization inevitably.To solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this paper.First,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are analyzed.Then,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space targets.Thereafter,the RCM and DFM are corrected by the compensation function correlated with the estimated motion parameters.Finally,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo signal.Numerical simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection.
文摘目的从生物信息学角度了解空肠弯曲菌主要外膜蛋白OMP18的跨膜结构、B细胞抗原表位及其抗原性、基因序列保守性等特征,并鉴定空肠弯曲菌主要外膜蛋白优势B细胞抗原表位,为后续抗体检测和疫苗研究提供实验依据。方法使用NCBI/Blast,TMHMM Server V2.0,DNA Star等生物信息学分析软件对空肠弯曲菌主要外膜蛋白OMP18进行蛋白跨膜结构预测、线性B细胞抗原表位及其抗原性分析、并对不同空肠弯曲菌OMP18蛋白的氨基酸序列同源性进行比较。采用空肠弯曲菌全菌抗体IgG为一抗,基于ELISA技术对优势线性B细胞抗原表位进行筛选鉴定。结果生物信息学预测结果表明外膜蛋白OMP18定位于空肠弯曲菌外膜且不存在跨膜结构。蛋白序列保守存在于各空肠弯曲菌株中,序列同源性达95%以上。同时,我们发现该外膜蛋白中存在3个明显的B细胞线性表位,且具有很强的抗原性。ELISA检测鉴定结果表明3个B细胞抗原表位都能有效识别空肠弯曲菌全菌抗体。结论空肠弯曲菌主要外膜蛋白OMP18保守存在于细菌表面,存在3个重要的B细胞线性抗原表位,可用于后续的抗体检测和疫苗开发研究。
基金supported by the Fundamental Research Funds for the Central Universities under Grant 20720200092the National Natural Science Foundation of China under Grant 62171394,U21A20444,61771152,62071402+2 种基金the Sustainable Funding of the Key Laboratory of Underwater Acoustic Technology under Grant JCKYS2022604SSJS001Key Laboratory of Universal Wireless Communications(BUPT)Ministry of Education,P.R.China under Grant KFKT-2022103.
文摘In this paper,in order to reduce the energy leakage caused by the discretized representation in sparse channel estimation for Orthogonal Frequency Division Multiplexing(OFDM)systems,we systematically have analyzed the optimal locations of atoms with discrete delays for each path reconstruction from the perspective of linear fitting theory.Then,we have investigated the adverse effects of the non-ideal inner product function on the iteration in one of the most widely used channel estimation method,Orthogonal Matching Pursuit(OMP).The study shows that the distance between the selected atoms for each path in OMP can be larger than the sampling interval,which prevents OMP-based methods from achieving better performance.To overcome this drawback,the image deblurring-based channel estimation method,in which the channel estimation problem is analogized to one-dimensional image deblurring,was proposed to improve the large compensation distance of traditional OMP.The advantage of the proposed method was validated by the results of numerical simulation and sea trial data decoding.
文摘目的通过观察苗药头花蓼作用前后的幽门螺杆菌(Helicobacter pylori,H.pylori)外膜蛋白(outer membrane protein,omp)及omp8、omp32基因表达水平的变化,探讨头花蓼抑制H.pylori生长活性的机制。方法应用Western blot及Real time PCR技术检测苗药头花蓼作用前后,H.pylori外膜蛋白及omp8、omp32 mRNA表达量的变化。结果 Western blot结果显示,苗药头花蓼作用后omp较对照组升高,具有统计学差异(P<0.05);Real time PCR结果显示,H.pylori在苗药头花蓼作用后其omp8、omp32 mRNA表达量分别较对照组上调2.339倍和2.597倍,具有统计学意义(P<0.05)。结论苗药头花蓼通过上调H.pylori外膜蛋白及omp8、omp32 mRNA水平,引起外膜通透性改变,从而发挥抗菌作用。
