Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correl...Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correlation with high efficiency. In order to improve the performance of the correlator, this paper proposes a new 1.5 bit quantization method. Theoretical analyses are made from the aspects of complexity and quantization loss, and performance comparison between 1.5 bit quantization correlator and traditional correlators is discussed. The results show that the 1.5 bit quantization algorithm can save about 30 percent complexity under similar quantization loss, reduce more than 0.5 dB signal noise ratio（SNR） loss under similar complexity. It shows great performance improvement for correlators of satellite navigation software receivers.展开更多
设计了一种基于1 bit Sigma-Delta调制技术的数字磁通门磁强计,并利用Matlab Simulink工具对其进行仿真建模与分析,获得了系统在噪声、线性度、动态响应速度以及频率响应等方面的性能参数.在±1000 nT量程范围内,该磁强计系统在1 H...设计了一种基于1 bit Sigma-Delta调制技术的数字磁通门磁强计,并利用Matlab Simulink工具对其进行仿真建模与分析,获得了系统在噪声、线性度、动态响应速度以及频率响应等方面的性能参数.在±1000 nT量程范围内,该磁强计系统在1 Hz处的噪声为0.17 pT·Hz-1/2,最大线性误差为1.04 pT,动态响应速度为1.07×10^(3) nT·s^(-1),频率响应带宽超过30 Hz.仿真结果证实,采用1 bit Sigma-Delta调制技术显著提高了数模转换器(Digital-to-Analog Converter,DAC)的转换精度,有效降低了数字磁强计系统的本底噪声和非线性误差,显著提升了数字磁强计的性能.基于1 bit Sigma-Delta调制技术的数字磁通门磁强计性能指标能够满足高精度磁场探测任务的要求,为空间磁场探测领域提供了一种高精度、高可靠性的探测手段,在深空探测及空间科学领域具有广泛的应用前景.展开更多
Quantization noise caused by analog-to-digital converter(ADC)gives rise to the reliability performance degradation of communication systems.In this paper,a quantized non-Hermitian symmetry(NHS)orthogonal frequency-div...Quantization noise caused by analog-to-digital converter(ADC)gives rise to the reliability performance degradation of communication systems.In this paper,a quantized non-Hermitian symmetry(NHS)orthogonal frequency-division multiplexing-based visible light communication(OFDM-VLC)system is presented.In order to analyze the effect of the resolution of ADC on NHS OFDM-VLC,a quantized mathematical model of NHS OFDM-VLC is established.Based on the proposed quantized model,a closed-form bit error rate(BER)expression is derived.The theoretical analysis and simulation results both confirm the effectiveness of the obtained BER formula in high-resolution ADC.In addition,channel coding is helpful in compensating for the BER performance loss due to the utilization of lower resolution ADC.展开更多
Anoikis is a specialized form of programmed cell death triggered by the detachment of cells from the extracellular matrix(ECM).Tumor cells that develop resistance to anoikis acquire the ability to detach,migrate,and c...Anoikis is a specialized form of programmed cell death triggered by the detachment of cells from the extracellular matrix(ECM).Tumor cells that develop resistance to anoikis acquire the ability to detach,migrate,and colonize distant sites,ultimately leading to the formation of metastatic tumors.Bit1(Bcl-2 inhibitor of transcription 1),a key effector of anoikis,is released into the cytoplasm upon loss of cell attachment and activates a caspase-independent pathway of apoptosis.Newcastle disease virus(NDV),a pathogen that poses a significant threat to the poultry industry,has also emerged as a promising oncolytic virus capable of selectively targeting and killing tumor cells.However,whether NDV can induce the death of anoikis-resistant tumor cells by activating Bit1 remains unclear.In this study,we utilized physical methods to induce cell suspension as a positive control for anoikis and further examined the expression and cellular localization of Bit1 following NDV infection in tumor cells.The results indicated that both viral infection and cell suspension resulted in partial cell death,accompanied by the translocation of Bit1 from the mitochondria to the cytoplasm and a reduction in its protein levels.Notably,Bit1 expression was found not to significantly affect viral replication.These findings suggest that NDV infection promotes tumor cell death by activating Bit1 translocation,mirroring the effects observed during cell suspension-induced anoikis.In addition,in vivo experiments demonstrated that NDV effectively inhibits the metastasis and growth of melanoma in mice,and that overexpression of Bit1 in tumor cells accelerates this process.This study provides novel insights into NDV-induced tumor cell death and identifies potential targets for understanding the mechanisms of oncolytic virus action.展开更多
Using the Faddeev-Jackiw （FJ） quantization method, this paper treats the CP^1nonlinear sigma model with ChernSimons term. The generalized FJ brackets are obtained in the framework of this quantization method, which ...Using the Faddeev-Jackiw （FJ） quantization method, this paper treats the CP^1nonlinear sigma model with ChernSimons term. The generalized FJ brackets are obtained in the framework of this quantization method, which agree with the results obtained by using the Dirac＇s method.展开更多
目的:探讨BIT1(Bcl-2 inhibitor of transcription1)基因在伴淋巴结转移的食管鳞癌组织中的表达及与食管鳞癌侵袭、转移的关系。方法:采用半定量RT-PCR法检测30例食管鳞癌、30例癌旁不典型增生组织及30例正常食管粘膜组织中BIT1基因的...目的:探讨BIT1(Bcl-2 inhibitor of transcription1)基因在伴淋巴结转移的食管鳞癌组织中的表达及与食管鳞癌侵袭、转移的关系。方法:采用半定量RT-PCR法检测30例食管鳞癌、30例癌旁不典型增生组织及30例正常食管粘膜组织中BIT1基因的相对表达量。结果:BIT1基因的表达在癌组织中均高于不典型增生组织及正常食管粘膜组织(P<0.05),而其在不典型增生及正常食管粘膜中无统计学意义(P>0.05)。BIT1基因的表达水平与患者的年龄、性别及肿瘤浸润深度均无明显相关(P>0.05),但其表达水平与淋巴结转移及临床TNM分期有关。BIT1基因在淋巴结转移组中的表达明显高于无淋巴结转移组(P<0.001);BIT1基因在TNMⅢ/Ⅳ期组中的表达明显高于Ⅰ/Ⅱ期组(P<0.05)。结论:BIT1基因高表达可能与食管鳞癌的侵袭、转移有关。展开更多
基金supported by the National Natural Science Foundation of China(61101076413741376147017)
文摘Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correlation with high efficiency. In order to improve the performance of the correlator, this paper proposes a new 1.5 bit quantization method. Theoretical analyses are made from the aspects of complexity and quantization loss, and performance comparison between 1.5 bit quantization correlator and traditional correlators is discussed. The results show that the 1.5 bit quantization algorithm can save about 30 percent complexity under similar quantization loss, reduce more than 0.5 dB signal noise ratio（SNR） loss under similar complexity. It shows great performance improvement for correlators of satellite navigation software receivers.
文摘设计了一种基于1 bit Sigma-Delta调制技术的数字磁通门磁强计,并利用Matlab Simulink工具对其进行仿真建模与分析,获得了系统在噪声、线性度、动态响应速度以及频率响应等方面的性能参数.在±1000 nT量程范围内,该磁强计系统在1 Hz处的噪声为0.17 pT·Hz-1/2,最大线性误差为1.04 pT,动态响应速度为1.07×10^(3) nT·s^(-1),频率响应带宽超过30 Hz.仿真结果证实,采用1 bit Sigma-Delta调制技术显著提高了数模转换器(Digital-to-Analog Converter,DAC)的转换精度,有效降低了数字磁强计系统的本底噪声和非线性误差,显著提升了数字磁强计的性能.基于1 bit Sigma-Delta调制技术的数字磁通门磁强计性能指标能够满足高精度磁场探测任务的要求,为空间磁场探测领域提供了一种高精度、高可靠性的探测手段,在深空探测及空间科学领域具有广泛的应用前景.
基金supported by the National Natural Science Foundation of China(No.62201508)the Zhejiang Provincial Natural Science Foundation of China(Nos.LZ21F010001 and LQ23F010004)the State Key Laboratory of Millimeter Waves of Southeast University,China(No.K202212).
文摘Quantization noise caused by analog-to-digital converter(ADC)gives rise to the reliability performance degradation of communication systems.In this paper,a quantized non-Hermitian symmetry(NHS)orthogonal frequency-division multiplexing-based visible light communication(OFDM-VLC)system is presented.In order to analyze the effect of the resolution of ADC on NHS OFDM-VLC,a quantized mathematical model of NHS OFDM-VLC is established.Based on the proposed quantized model,a closed-form bit error rate(BER)expression is derived.The theoretical analysis and simulation results both confirm the effectiveness of the obtained BER formula in high-resolution ADC.In addition,channel coding is helpful in compensating for the BER performance loss due to the utilization of lower resolution ADC.
基金supported by the National Key Research and Development Program of China(2022YFD1801500)the International Cooperation Project of National Natural Science Foundation of China(32220103012)the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSLPDCP-202402).
文摘Anoikis is a specialized form of programmed cell death triggered by the detachment of cells from the extracellular matrix(ECM).Tumor cells that develop resistance to anoikis acquire the ability to detach,migrate,and colonize distant sites,ultimately leading to the formation of metastatic tumors.Bit1(Bcl-2 inhibitor of transcription 1),a key effector of anoikis,is released into the cytoplasm upon loss of cell attachment and activates a caspase-independent pathway of apoptosis.Newcastle disease virus(NDV),a pathogen that poses a significant threat to the poultry industry,has also emerged as a promising oncolytic virus capable of selectively targeting and killing tumor cells.However,whether NDV can induce the death of anoikis-resistant tumor cells by activating Bit1 remains unclear.In this study,we utilized physical methods to induce cell suspension as a positive control for anoikis and further examined the expression and cellular localization of Bit1 following NDV infection in tumor cells.The results indicated that both viral infection and cell suspension resulted in partial cell death,accompanied by the translocation of Bit1 from the mitochondria to the cytoplasm and a reduction in its protein levels.Notably,Bit1 expression was found not to significantly affect viral replication.These findings suggest that NDV infection promotes tumor cell death by activating Bit1 translocation,mirroring the effects observed during cell suspension-induced anoikis.In addition,in vivo experiments demonstrated that NDV effectively inhibits the metastasis and growth of melanoma in mice,and that overexpression of Bit1 in tumor cells accelerates this process.This study provides novel insights into NDV-induced tumor cell death and identifies potential targets for understanding the mechanisms of oncolytic virus action.
文摘Using the Faddeev-Jackiw （FJ） quantization method, this paper treats the CP^1nonlinear sigma model with ChernSimons term. The generalized FJ brackets are obtained in the framework of this quantization method, which agree with the results obtained by using the Dirac＇s method.
文摘目的:探讨BIT1(Bcl-2 inhibitor of transcription1)基因在伴淋巴结转移的食管鳞癌组织中的表达及与食管鳞癌侵袭、转移的关系。方法:采用半定量RT-PCR法检测30例食管鳞癌、30例癌旁不典型增生组织及30例正常食管粘膜组织中BIT1基因的相对表达量。结果:BIT1基因的表达在癌组织中均高于不典型增生组织及正常食管粘膜组织(P<0.05),而其在不典型增生及正常食管粘膜中无统计学意义(P>0.05)。BIT1基因的表达水平与患者的年龄、性别及肿瘤浸润深度均无明显相关(P>0.05),但其表达水平与淋巴结转移及临床TNM分期有关。BIT1基因在淋巴结转移组中的表达明显高于无淋巴结转移组(P<0.001);BIT1基因在TNMⅢ/Ⅳ期组中的表达明显高于Ⅰ/Ⅱ期组(P<0.05)。结论:BIT1基因高表达可能与食管鳞癌的侵袭、转移有关。
