Geological anomalies,including faults,fractured zones,and collapse pillars,pose serious threats to mining safety by increasing the risk of water inrush and roof collapse.To enable accurate ahead-of-face detection,this...Geological anomalies,including faults,fractured zones,and collapse pillars,pose serious threats to mining safety by increasing the risk of water inrush and roof collapse.To enable accurate ahead-of-face detection,this paper presents the development and practical application of a single-borehole impulse radar(BHR)system specifically designed for underground coal mine environments.The system incorporates a compact,explosion-proof probe constructed from fiberglass,with a diameter of 40 mm,making it suitable for deployment in confined boreholes.By leveraging wideband impulse signals,the BHR achieves high-resolution subsurface imaging while maintaining low power consumption and rapid data acquisition rates.The system’s detection performance was first verified through controlled ground experiments in a railway tunnel,where it accurately identified karst structures—a finding later confirmed by subsequent excavation.Field applications at Wangzhuang and Madaotou coal mines demonstrated its effectiveness in identifying fracture zones,water-rich strata,and fault systems.Repeated measurements across multiple boreholes demonstrated high detection stability and strong consistency with actual exposed geological conditions.Although operational challenges such as signal transmission in narrow spaces and high sampling rate requirements persist,the proposed system successfully balances imaging resolution,operational portability,and real-time processing capability.The results affirm the significant potential of impulse borehole radar for enhancing geological forecasting and improving safety in underground coal mining operations.展开更多
The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the ang...The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the angle-dependent beampattern to an angle-time-range-dependent three-dimensional function by modulating the frequencies/time delays/phases across different transmit antenna elements.In this respect,extra Degrees-of-Freedom(DOFs)in the range domain are achieved,which opens up an innovative way to fulfil the tasks with enhanced system performance by jointly using the angle and range information.This paper summaries the developments of waveform diverse radars,including the Frequency Diverse Array(FDA),the Space-Time-CirculatingArray(STCA),and the Element-Pulse-Coding(EPC)frameworks,with emphasis on the analysis of the range-dependent beampattern from the basic properties upon how it is controlled.Moreover,the most recent advances of utilizing such a range-dependent beampattern in target detection,parameter estimation and identifiability,clutter suppression,jammer suppression and Synthetic Aperture Radar(SAR)imaging are discussed.展开更多
RadA is highly conserved in bacteria and belongs to the RecA/RadA/Rad51 protein su-perfamily found in bacteria,archaea and eukarya. In Archaea,it plays a critical role in homologous re-combination process due to its R...RadA is highly conserved in bacteria and belongs to the RecA/RadA/Rad51 protein su-perfamily found in bacteria,archaea and eukarya. In Archaea,it plays a critical role in homologous re-combination process due to its RecA-like function. In Escherichia coli,it takes part in conjugational recom-bination and DNA repair but is not as important as that of archaea. Using PSI-BLAST searches,we found that Deinococcus radiodurans RadA had a higher similarity to that of bacteria than archaea and eukarya. Disruption of radA gene in D. radiodurans resulted in a modestly decreased resistance to gamma radiation and ultraviolet,but had no effect on the resistance to hydrogen peroxide. Complementa-tion of the radA disruptant by both E. coli radA and D. radiodurans radA could fully restore its resistance to gamma radiation and ultraviolet irradiation. Further domain function analyses of D. radiodurans RadA showed that the absence of the zinc finger domain resulted in a slightly more sensitive phenotype to gamma and UV radiation than that of the radA mutant,while the absence of the Lon protease domain exhib-ited a slightly increased resistance to gamma and UV radiation. These data suggest that D. radiodurans RadA does play an important role in the DNA damage repair processes and its three different domains have different functions.展开更多
Rad51/RadA paralogs found in eukaryotes and euryarchaea play important roles during recombination and repair,and mutations in one of the human Rad51 paralogs,Rad51C,are associated with breast and ovarian cancers.The h...Rad51/RadA paralogs found in eukaryotes and euryarchaea play important roles during recombination and repair,and mutations in one of the human Rad51 paralogs,Rad51C,are associated with breast and ovarian cancers.The hyperthermophilic crenarchaeon Sulfolobus tokodaii encodes four putative RadA paralogs and studies on these proteins may assist in understanding the functions of human Rad51 paralogs.Here,we report the biochemical characterization of stRadC2,a S.tokodaii RadA paralog.Pull-down assays revealed that the protein was able to interact with the recombinase,RadA,and the Holliday junction endonuclease,Hjc.stRadC2 inhibited the strand exchange activity of RadA and facilitated Hjc-mediated Holliday junction DNA cleavage in vitro.RT-PCR analysis revealed that stRadC2 transcription was immediately reduced after UV irradiation,but was restored to normal levels at the late stages of DNA repair.Our results suggest that stRadC2 may act as an anti-recombination factor in DNA recombinational repair in S.tokodaii.展开更多
基金supported by CHN Shenhua Energy Co.Ltd.Shendong Coal Branch(Grant Nos.E210100720).
文摘Geological anomalies,including faults,fractured zones,and collapse pillars,pose serious threats to mining safety by increasing the risk of water inrush and roof collapse.To enable accurate ahead-of-face detection,this paper presents the development and practical application of a single-borehole impulse radar(BHR)system specifically designed for underground coal mine environments.The system incorporates a compact,explosion-proof probe constructed from fiberglass,with a diameter of 40 mm,making it suitable for deployment in confined boreholes.By leveraging wideband impulse signals,the BHR achieves high-resolution subsurface imaging while maintaining low power consumption and rapid data acquisition rates.The system’s detection performance was first verified through controlled ground experiments in a railway tunnel,where it accurately identified karst structures—a finding later confirmed by subsequent excavation.Field applications at Wangzhuang and Madaotou coal mines demonstrated its effectiveness in identifying fracture zones,water-rich strata,and fault systems.Repeated measurements across multiple boreholes demonstrated high detection stability and strong consistency with actual exposed geological conditions.Although operational challenges such as signal transmission in narrow spaces and high sampling rate requirements persist,the proposed system successfully balances imaging resolution,operational portability,and real-time processing capability.The results affirm the significant potential of impulse borehole radar for enhancing geological forecasting and improving safety in underground coal mining operations.
基金supported in part by the National Nature Science Foundation of China(Nos.62101402,61931016,62071344)China Postdoctoral Science Foundation(Nos.2021TQ0261,2021M702547)Young Elite Scientists Sponsorship Program by CAST(2021QNRC001).
文摘The transmit antenna beampattern of the phased array radar is only a function of angle,limiting its ability to discriminate the targets from the same direction.Recently,the waveform diverse array radars expand the angle-dependent beampattern to an angle-time-range-dependent three-dimensional function by modulating the frequencies/time delays/phases across different transmit antenna elements.In this respect,extra Degrees-of-Freedom(DOFs)in the range domain are achieved,which opens up an innovative way to fulfil the tasks with enhanced system performance by jointly using the angle and range information.This paper summaries the developments of waveform diverse radars,including the Frequency Diverse Array(FDA),the Space-Time-CirculatingArray(STCA),and the Element-Pulse-Coding(EPC)frameworks,with emphasis on the analysis of the range-dependent beampattern from the basic properties upon how it is controlled.Moreover,the most recent advances of utilizing such a range-dependent beampattern in target detection,parameter estimation and identifiability,clutter suppression,jammer suppression and Synthetic Aperture Radar(SAR)imaging are discussed.
基金Acknowledgements The authors would like to thank Prof. Fu Junjie （Radiation Center of Zhejiang University） for his help in irradiation treatment. This work was supported by the National Basic Research Program of China （Grant No. 2004CB19604）, a grant for Distinguished Young Scientist of China （Grant No. 30425038） and the National Natural Science Foundation of China （Grant No. 30330020）.
文摘RadA is highly conserved in bacteria and belongs to the RecA/RadA/Rad51 protein su-perfamily found in bacteria,archaea and eukarya. In Archaea,it plays a critical role in homologous re-combination process due to its RecA-like function. In Escherichia coli,it takes part in conjugational recom-bination and DNA repair but is not as important as that of archaea. Using PSI-BLAST searches,we found that Deinococcus radiodurans RadA had a higher similarity to that of bacteria than archaea and eukarya. Disruption of radA gene in D. radiodurans resulted in a modestly decreased resistance to gamma radiation and ultraviolet,but had no effect on the resistance to hydrogen peroxide. Complementa-tion of the radA disruptant by both E. coli radA and D. radiodurans radA could fully restore its resistance to gamma radiation and ultraviolet irradiation. Further domain function analyses of D. radiodurans RadA showed that the absence of the zinc finger domain resulted in a slightly more sensitive phenotype to gamma and UV radiation than that of the radA mutant,while the absence of the Lon protease domain exhib-ited a slightly increased resistance to gamma and UV radiation. These data suggest that D. radiodurans RadA does play an important role in the DNA damage repair processes and its three different domains have different functions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 3093002 and 30870046 to Shen YuLong,and 30700011 to Sheng DuoHong)the Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province (Grant No. BS2010SW014 to Sheng DuoHong)
文摘Rad51/RadA paralogs found in eukaryotes and euryarchaea play important roles during recombination and repair,and mutations in one of the human Rad51 paralogs,Rad51C,are associated with breast and ovarian cancers.The hyperthermophilic crenarchaeon Sulfolobus tokodaii encodes four putative RadA paralogs and studies on these proteins may assist in understanding the functions of human Rad51 paralogs.Here,we report the biochemical characterization of stRadC2,a S.tokodaii RadA paralog.Pull-down assays revealed that the protein was able to interact with the recombinase,RadA,and the Holliday junction endonuclease,Hjc.stRadC2 inhibited the strand exchange activity of RadA and facilitated Hjc-mediated Holliday junction DNA cleavage in vitro.RT-PCR analysis revealed that stRadC2 transcription was immediately reduced after UV irradiation,but was restored to normal levels at the late stages of DNA repair.Our results suggest that stRadC2 may act as an anti-recombination factor in DNA recombinational repair in S.tokodaii.
