"天问一号"微波着陆雷达是探测器进入、下降与着陆(Entry,descent and landing,EDL)阶段的关键单机,采用了线性调频连续波(Linear frequency modulation continuous wave,LFMCW)体制,如何有效抑制LFMCW雷达接收回波中耦合的..."天问一号"微波着陆雷达是探测器进入、下降与着陆(Entry,descent and landing,EDL)阶段的关键单机,采用了线性调频连续波(Linear frequency modulation continuous wave,LFMCW)体制,如何有效抑制LFMCW雷达接收回波中耦合的直波泄漏信号一直是提高雷达性能的关键问题。本文从雷达系统设计的角度出发,在满足系统轻小型化要求的前提下,提出了高隔离度天线设计、接收机中频输出信号滤波设计以及数字信号处理中泄露信号抑制相结合的方法,有效地解决了LFMCW雷达直波泄露的问题。通过分析外场直升机校飞试验实测数据,证明采用上述方法后,可大幅抑制直波泄露信号,并可将直波泄露信号携带的相位噪声抑制10~15 dB。展开更多
To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, C...To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, China） with vitrinite reflectance of 0.64% to 1.34%. Low-pressure gas adsorption experiments were conducted on the samples before and after extraction. The pore structure parameters were calculated from the gas adsorption data. The results show complex changes to the pore volumes and surface areas after extraction. The pore development of both the initial and extracted samples is strongly controlled by total organic carbon （TOC） content. Micropores developed mainly in organic matter （OM）, while mesopores and macropores predominantly developed in fractions other than OM. The influence of EOM on micropores is stronger than on mesopores and macropores. Organic solvents with a higher boiling point should be used to explore the effect of EOM on pore structure in the future.展开更多
胃癌因其高流行状态已成为我国一大公共卫生问题。环状RNA(circRNA)由于可稳定存在于人类的多种体液中,具备液态活检的先天优势,成为近年来精准治疗领域的研究热点。本文通过检索PubMed、Web of Science、中国知网等数据库文献,基于circ...胃癌因其高流行状态已成为我国一大公共卫生问题。环状RNA(circRNA)由于可稳定存在于人类的多种体液中,具备液态活检的先天优势,成为近年来精准治疗领域的研究热点。本文通过检索PubMed、Web of Science、中国知网等数据库文献,基于circRNA的生物学特征,归纳circRNA在胃癌早期筛查诊断、疗效监测、预后评估等方面的研究进展,论述circRNA作为新兴液体活检标志物的可能性及可靠性,为今后circRNA作为胃癌临床诊疗、评估、预后分子标志物的开发和转化提供思路。展开更多
目的应用宏基因组学二代测序(metagenomics next generation sequencing,mNGS)技术检测重症肺炎真菌感染患者病原体,探讨其诊断重症肺炎真菌感染的临床应用价值。方法重症肺炎真菌感染患者20例,其中经传统病原微生物培养(痰培养、肺泡...目的应用宏基因组学二代测序(metagenomics next generation sequencing,mNGS)技术检测重症肺炎真菌感染患者病原体,探讨其诊断重症肺炎真菌感染的临床应用价值。方法重症肺炎真菌感染患者20例,其中经传统病原微生物培养(痰培养、肺泡灌洗液/胸腔积液培养)明确病原学17例,另3例符合临床诊断标准,但未明确病原学。收集患者肺泡灌洗液标本19例,胸腔积液1例,并采用mNGS进一步检测病原体。结果经传统病原学检测明确病原学17例中,7例肺孢子菌,4例白色念珠菌,3例曲霉菌,1例肺孢子菌混合鲍曼不动杆菌,1例根霉菌,1例隐球菌;另3例符合真菌感染临床诊断者,经mNGS确定病原体1例为肺孢子菌感染合并白色念珠菌,2例为肺孢子菌感染合并鲍曼不动杆菌感染。7例传统培养明确肺孢子菌感染标本中,mNGS检测发现3例同时合并曲霉菌感染。1例mNGS测定未发现真菌,而肺泡灌洗液中培养出霉菌菌丝。20例患者mNGS检测检出肺孢子菌11例,曲霉菌6例,念珠菌5例,根霉菌1例,新型隐球菌感染(胸腔积液标本)1例。曲霉菌核酸序列数分别为3、42、6788、206、46、2条,测序深度为1~1.2,覆盖度为0.004%~11.000%;念珠菌核酸序列数分别为6、152、17、4、96条,测序深度为1~1.4,覆盖度为0.009%~18.000%;肺孢子菌核酸序列数分别为17、56737、40、1050、19153、3419、420、32828、45487、5、87条,测序深度为1~1.3,覆盖度为0.05%~16.00%;新型隐球菌1例,序列数52条;根霉菌1例,序列数11条。结论mNGS可快速检测真菌感染的病原体,提高重症肺炎病原学诊断的敏感性,可作为传统微生物检测手段的有效补充方法。展开更多
文摘"天问一号"微波着陆雷达是探测器进入、下降与着陆(Entry,descent and landing,EDL)阶段的关键单机,采用了线性调频连续波(Linear frequency modulation continuous wave,LFMCW)体制,如何有效抑制LFMCW雷达接收回波中耦合的直波泄漏信号一直是提高雷达性能的关键问题。本文从雷达系统设计的角度出发,在满足系统轻小型化要求的前提下,提出了高隔离度天线设计、接收机中频输出信号滤波设计以及数字信号处理中泄露信号抑制相结合的方法,有效地解决了LFMCW雷达直波泄露的问题。通过分析外场直升机校飞试验实测数据,证明采用上述方法后,可大幅抑制直波泄露信号,并可将直波泄露信号携带的相位噪声抑制10~15 dB。
基金funded by the National Science Foundation of China(41502144,41503034)the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-1612)+2 种基金the Fund of the Education Department of Sichuan Province(16ZA0075)the Youth Scientific Innovation Team of Hydrocarbon Accumulation and Geochemistry,Southwest Petroleum University(2015CXTD02)the Sichuan Province University Scientific Innovation Team Construction Project(USITCP)
文摘To investigate the influence of extractable organic matter （EOM） on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples （Ordos Basin, China） with vitrinite reflectance of 0.64% to 1.34%. Low-pressure gas adsorption experiments were conducted on the samples before and after extraction. The pore structure parameters were calculated from the gas adsorption data. The results show complex changes to the pore volumes and surface areas after extraction. The pore development of both the initial and extracted samples is strongly controlled by total organic carbon （TOC） content. Micropores developed mainly in organic matter （OM）, while mesopores and macropores predominantly developed in fractions other than OM. The influence of EOM on micropores is stronger than on mesopores and macropores. Organic solvents with a higher boiling point should be used to explore the effect of EOM on pore structure in the future.
文摘胃癌因其高流行状态已成为我国一大公共卫生问题。环状RNA(circRNA)由于可稳定存在于人类的多种体液中,具备液态活检的先天优势,成为近年来精准治疗领域的研究热点。本文通过检索PubMed、Web of Science、中国知网等数据库文献,基于circRNA的生物学特征,归纳circRNA在胃癌早期筛查诊断、疗效监测、预后评估等方面的研究进展,论述circRNA作为新兴液体活检标志物的可能性及可靠性,为今后circRNA作为胃癌临床诊疗、评估、预后分子标志物的开发和转化提供思路。
文摘目的应用宏基因组学二代测序(metagenomics next generation sequencing,mNGS)技术检测重症肺炎真菌感染患者病原体,探讨其诊断重症肺炎真菌感染的临床应用价值。方法重症肺炎真菌感染患者20例,其中经传统病原微生物培养(痰培养、肺泡灌洗液/胸腔积液培养)明确病原学17例,另3例符合临床诊断标准,但未明确病原学。收集患者肺泡灌洗液标本19例,胸腔积液1例,并采用mNGS进一步检测病原体。结果经传统病原学检测明确病原学17例中,7例肺孢子菌,4例白色念珠菌,3例曲霉菌,1例肺孢子菌混合鲍曼不动杆菌,1例根霉菌,1例隐球菌;另3例符合真菌感染临床诊断者,经mNGS确定病原体1例为肺孢子菌感染合并白色念珠菌,2例为肺孢子菌感染合并鲍曼不动杆菌感染。7例传统培养明确肺孢子菌感染标本中,mNGS检测发现3例同时合并曲霉菌感染。1例mNGS测定未发现真菌,而肺泡灌洗液中培养出霉菌菌丝。20例患者mNGS检测检出肺孢子菌11例,曲霉菌6例,念珠菌5例,根霉菌1例,新型隐球菌感染(胸腔积液标本)1例。曲霉菌核酸序列数分别为3、42、6788、206、46、2条,测序深度为1~1.2,覆盖度为0.004%~11.000%;念珠菌核酸序列数分别为6、152、17、4、96条,测序深度为1~1.4,覆盖度为0.009%~18.000%;肺孢子菌核酸序列数分别为17、56737、40、1050、19153、3419、420、32828、45487、5、87条,测序深度为1~1.3,覆盖度为0.05%~16.00%;新型隐球菌1例,序列数52条;根霉菌1例,序列数11条。结论mNGS可快速检测真菌感染的病原体,提高重症肺炎病原学诊断的敏感性,可作为传统微生物检测手段的有效补充方法。
