Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels....Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels. However, one research problem is still calling for solutions, how to identify the fishing vessel type based on only VMS trajectories. This problem is important because it requires the fishing vessel type as a preliminary to recognize fishing activities from VMS trajectories. This paper proposes fishing vessel type identification scheme(FVID) based only on VMS trajectories. FVID exploits feature engineering and machine learning schemes of XGBoost as its two key blocks and classifies fishing vessels into nine types. The dataset contains all the fishing vessel trajectories in the East China Sea in March 2017, including 10031 pre-registered fishing vessels and 1350 unregistered vessels of unknown types. In order to verify type identification accuracy, we first conduct a 4-fold cross-validation on the trajectories of registered fishing vessels. The classification accuracy is 95.42%. We then apply FVID to the unregistered fishing vessels to identify their types. After classifying the unregistered fishing vessel types, their fishing activities are further recognized based upon their types. At last, we calculate and compare the fishing density distribution in the East China Sea before and after applying the unregistered fishing vessels, confirming the importance of type identification of unregistered fishing vessels.展开更多
With the rapid increase of the number and influence of floating population in China,it is urgently needed to understand the regional types of China＇s floating population and their spatial characteristics. After revie...With the rapid increase of the number and influence of floating population in China,it is urgently needed to understand the regional types of China＇s floating population and their spatial characteristics. After reviewing the current methods for identifying regional types of floating population,this paper puts forward a new composite-index identification method and its modification version which is consisted of two indexes of the net migration rate and gross migration rate. Then,the traditional single-index and the new composite-index identification methods are empirically tested to explore their spatial patterns and characteristics by using China＇s 2000 census data at county level. The results show：（1） The composite-index identification method is much better than traditional single-index method because it can measure the migration direction and scale of floating simultaneously,and in particular it can identify the unique regional types of floating population with large scale of immigration and emigration. （2） The modified composite-index identification method,by using the share of a region＇s certain type of floating population to the total in China as weights,can effectively correct the over-or under-estimated errors due to the rather large or small total population of a region. （3） The spatial patterns of different regional types of China＇s floating population are closely related to the regional differentiation of their natural environment,population density and socio-economic development level. The three active regional types of floating population are mainly located in the eastern part of China with lower elevation,more than 800 mm precipitation,rather higher population densities and economic development levels.展开更多
[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determinati...[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determination of growth curve and correlation curve between OD 600 values and viable counts,drug susceptibility tests,pathogenicity analysis,and histopathological observations were carried out.[Results]The Streptococcus strain isolated from infected pigs was identified as Streptococcus suis type 2,which was named TA01 strain.TA01 strain reached the growth peak at 6-8 h post-incubation,and viable counts gradually declined after 8 h of incubation.The correlation equation between OD 600 values and viable counts is y=24.659 x-1.076 1,R^2=0.996 7.TA01 strain was sensitive to penicillin,erythromycin,florfenicol and oxacillin,and resistant to ciprofloxacin,polymyxin B and clindamycin.According to the results of pathogenicity analysis,all the mice in 3.6×10^9 cfu/mouse group died within 48,and these dead mice exhibited acute pyaemia septica.Based on the Reed-Muench formula,it was calculated that LD 50 of TA01 strain was 1.137×10^8 cfu/mouse.Pathological examination showed obvious blue-stained bacteria clusters,accompanied by neutrophil infiltration.[Conclusions]TA01 strain was a virulent strain of Streptococcus suis type 2.Compared with Streptococcus strains which were isolated and reported in China,TA01 strain exhibited strong virulence and rapid proliferation.展开更多
The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino...The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino acid sequence shows strong homology to eukaryotic DNA Top 2. However, some distortions were found, such as six insertions in the ATPase domain and the central domain, a -100 aa longer central domain; a ~200 aa shorter C-terminal domain containing rich charged residues. These features revealed by comparing with Top 2 of the host, human, might be helpful in exploiting drug selectivity for antigiardial therapy. Phylogenetic analysis of eukaryotic enzymes showed that kinetoplastids, plants, fungi, and animals were monophyletic groups, and the animal and fungi lineages shared a more recent common ancestor than either did with the plant lineage; microsporidia grouped with fungi. However, unlike many previous phylogenetic analyses, the ''amitochondriate'' G. lamblia was not the earliest branch but diverged after mitochondriate kinetoplastids in our trees. Both the finding of typical eukaryotic type IIA topoisomerase and the phylogenetic analysis suggest G, lamblia is not possibly as primitive as was regarded before and might diverge after the acquisition of mitochondria. This is consistent with the recent discovery of mitochondrial remnant organelles in G. lamblia.展开更多
[ Objective] In order to make out differences between drug resistance spectrum types of different animal sources of Salmonella. [ Meth- otis] Selenite cystine broth, Salmonella- Shigella genus agar medium, CHROMagar S...[ Objective] In order to make out differences between drug resistance spectrum types of different animal sources of Salmonella. [ Meth- otis] Selenite cystine broth, Salmonella- Shigella genus agar medium, CHROMagar Salmonella chromogenic culture, Reveal Salmonella detection kit and molecular biology methods were used for isolation and identification of Salmonella from different animal feces samples. Antibacterialantimi- crobial susceptibility tests of 17 kinds of drugs such as enrofloxacin, apramycin and florfenicol were done on isolated strains with broth microdilution method, and test data was analysed with WHOnet 5.4 software. [ Results ] 699 feces samples from different animals were separated, and 53 strains of Salmonella were achieved with separation rate of 7.58%, among which those of yak, poultry, and pet sources were respectively 4.33%, 9.06% and 8.37%. [ Condusions] Separation rates and drug resistance spectrum types of different animal origin Salmonella varied greatly, among which separation rates and drug resistance spectrum types of yak source Salmonella were the lowest, there was little difference between separation rates of poultry and dog source Salmonella, however there were large differences on drug resistance spectrum types.展开更多
Identification of reservoir types in deep carbonates has always been a great challenge due to complex logging responses caused by the heterogeneous scale and distribution of storage spaces.Traditional cross-plot analy...Identification of reservoir types in deep carbonates has always been a great challenge due to complex logging responses caused by the heterogeneous scale and distribution of storage spaces.Traditional cross-plot analysis and empirical formula methods for identifying reservoir types using geophysical logging data have high uncertainty and low efficiency,which cannot accurately reflect the nonlinear relationship between reservoir types and logging data.Recently,the kernel Fisher discriminant analysis(KFD),a kernel-based machine learning technique,attracts attention in many fields because of its strong nonlinear processing ability.However,the overall performance of KFD model may be limited as a single kernel function cannot simultaneously extrapolate and interpolate well,especially for highly complex data cases.To address this issue,in this study,a mixed kernel Fisher discriminant analysis(MKFD)model was established and applied to identify reservoir types of the deep Sinian carbonates in central Sichuan Basin,China.The MKFD model was trained and tested with 453 datasets from 7 coring wells,utilizing GR,CAL,DEN,AC,CNL and RT logs as input variables.The particle swarm optimization(PSO)was adopted for hyper-parameter optimization of MKFD model.To evaluate the model performance,prediction results of MKFD were compared with those of basic-kernel based KFD,RF and SVM models.Subsequently,the built MKFD model was applied in a blind well test,and a variable importance analysis was conducted.The comparison and blind test results demonstrated that MKFD outperformed traditional KFD,RF and SVM in the identification of reservoir types,which provided higher accuracy and stronger generalization.The MKFD can therefore be a reliable method for identifying reservoir types of deep carbonates.展开更多
In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome （PMWS） broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and gr...In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome （PMWS） broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and grinded into tissue suspension. The suspension was subjected to PCR detection, and the positive product was sequenced. The suspension of positive samples was filtered with 0.22 μm filter membrane, and the filtrate was inoculated onto PK15 cells. After five generations of blind passages, the cell viral liquid was collected and extracted for DNA, which was subjected to PCR detection and indirect immunofluorescence. The results showed that the isolate was porcine circovirus type 2 （PCV2） and designated as TAIZ110926. The target sequence was committed to NCBI with a serial number： KF039888.展开更多
The results of geological research show that those phenomena such as surface geology,geomorphology,deep geophysical field,and time-space distribution of seismicities can be usedas the main seismogeological indicators ...The results of geological research show that those phenomena such as surface geology,geomorphology,deep geophysical field,and time-space distribution of seismicities can be usedas the main seismogeological indicators to identify the newly-generated seismic rupture zone(NSRZ).According to their formation and evolution process,the NSRZs can be divided intothree types:pre-rupture-isolated,quasi-rupture-discontinuous and major-rupture-connected.In a pre-rupture-isolated NSRZ,the seismicity is dominated by medium-small earthquakes.In a quasi-rupture-discontinuous NSRZ,the frequency and intensity of strong earthquakesincrease and there may even be the largest earthquake to occur.A major-rupture-connectedNSRZ is the segment where rupture has entered the mature stage;in such a zone,theintensity and duration of seismic activity depend on the constitutive condition and regionalstress field in the zone.展开更多
The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing rati...The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing ratio of source-mixed gas. Besides, this research quantitatively investigated the natural gas generated by different types of organic matter. The results show that different ratios of source-mixed gas exist in the 6 oil-gas fields at the northern margin of Qaidam Basin. Among them, Mabei has the highest mixing ratio of coal-type gas, followed by Nanbaxian, Mahai, Lenghu-4, Lenghu-3 and Lenghu-5, with the ratios of coal-type gas 91%, 87%, 83%, 66%, 55% and 36%, respectively. Lenghu-3 and Lenghu-4 oil-gas fields were mainly filled by coal-type gas earlier. For Lenghu-3, the gas was mainly generated from low matured source rocks in lower Jurassic Series of Lengxi sub-sag. For Lenghu-4, the gas was mainly generated from humus-mature source rocks in lower Jurassic Series of the northern slope of Kunteyi sub-sag. Gas in Lenghu-5 was mainly later filled oil-type gas, which was generated from high matured sapropelics in lower Jurassic Series of Kunteyi sub-sag. Earlier filled coal-type gas was the main part of Mahai, Nanbaxian and Mabei oil-gas fields. Gas source of Mahai was mainly generated from high mature humics in lower Jurassic Series of Yibei sub-sag; for Nanbaxian, the gas was mainly generated from high matured humics in middle-lower Jurassic Series of Saishiteng sub-sag; for Mabei, the gas was mainly generated from humus-mature source rocks in middle Jurassic Series of Yuqia sub-sag.展开更多
Dynamic stress adjustment in deep-buried high geostress hard rock tunnels frequently triggers catastrophic failures such as rockbursts and collapses.While a comprehensive understanding of this process is critical for ...Dynamic stress adjustment in deep-buried high geostress hard rock tunnels frequently triggers catastrophic failures such as rockbursts and collapses.While a comprehensive understanding of this process is critical for evaluating surrounding rock stability,its dynamic evolution are often overlooked in engineering practice.This study systematically summarizes a novel classification framework for stress adjustment types—stabilizing(two-zoned),shallow failure(three-zoned),and deep failure(four-zoned)—characterized by distinct stress adjustment stages.A dynamic interpretation technology system is developed based on microseismic monitoring,integrating key microseismic parameters(energy index EI,apparent stressσa,microseismic activity S),seismic source parameter space clustering,and microseismic paths.This approach enables precise identification of evolutionary stages,stress adjustment types,and failure precursors,thereby elucidating the intrinsic linkage between geomechanical processes(stress redistribution)and failure risks.The study establishes criteria and procedures for identifying stress adjustment types and their associated failure risks,which were successfully applied in the Grand Canyon Tunnel of the E-han Highway to detect 50 instances of disaster risks.The findings offer invaluable insights into understanding the evolution process of stress adjustment and pinpointing the disaster risks linked to hard rock in comparable high geostress tunnels.展开更多
基金partially supported by National Key R&D Program (No. 2016YFC 1401900)the National Natural Science Foundation of China (Nos. 61379127, 61379128, 61572448)+1 种基金the Fundamental Research Funds for the Central Universities (No. 201713016)Qingdao National Laboratory for Marine Science and Technology Open Research Project (No. QNLM2016ORP 0405)
文摘Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels. However, one research problem is still calling for solutions, how to identify the fishing vessel type based on only VMS trajectories. This problem is important because it requires the fishing vessel type as a preliminary to recognize fishing activities from VMS trajectories. This paper proposes fishing vessel type identification scheme(FVID) based only on VMS trajectories. FVID exploits feature engineering and machine learning schemes of XGBoost as its two key blocks and classifies fishing vessels into nine types. The dataset contains all the fishing vessel trajectories in the East China Sea in March 2017, including 10031 pre-registered fishing vessels and 1350 unregistered vessels of unknown types. In order to verify type identification accuracy, we first conduct a 4-fold cross-validation on the trajectories of registered fishing vessels. The classification accuracy is 95.42%. We then apply FVID to the unregistered fishing vessels to identify their types. After classifying the unregistered fishing vessel types, their fishing activities are further recognized based upon their types. At last, we calculate and compare the fishing density distribution in the East China Sea before and after applying the unregistered fishing vessels, confirming the importance of type identification of unregistered fishing vessels.
基金Foundation： Knowledge Innovation Program of the Chinese Academy of Sciences, No.KZCX2-YW-322, National Natural Science Foundation of China, No.40971102 The National Science and Technology Support Plan, No.2006BAJ11B02-04
文摘With the rapid increase of the number and influence of floating population in China,it is urgently needed to understand the regional types of China＇s floating population and their spatial characteristics. After reviewing the current methods for identifying regional types of floating population,this paper puts forward a new composite-index identification method and its modification version which is consisted of two indexes of the net migration rate and gross migration rate. Then,the traditional single-index and the new composite-index identification methods are empirically tested to explore their spatial patterns and characteristics by using China＇s 2000 census data at county level. The results show：（1） The composite-index identification method is much better than traditional single-index method because it can measure the migration direction and scale of floating simultaneously,and in particular it can identify the unique regional types of floating population with large scale of immigration and emigration. （2） The modified composite-index identification method,by using the share of a region＇s certain type of floating population to the total in China as weights,can effectively correct the over-or under-estimated errors due to the rather large or small total population of a region. （3） The spatial patterns of different regional types of China＇s floating population are closely related to the regional differentiation of their natural environment,population density and socio-economic development level. The three active regional types of floating population are mainly located in the eastern part of China with lower elevation,more than 800 mm precipitation,rather higher population densities and economic development levels.
基金Supported by National Key Basic Research Program of China(973 Program)(2017YFD0500605)
文摘[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determination of growth curve and correlation curve between OD 600 values and viable counts,drug susceptibility tests,pathogenicity analysis,and histopathological observations were carried out.[Results]The Streptococcus strain isolated from infected pigs was identified as Streptococcus suis type 2,which was named TA01 strain.TA01 strain reached the growth peak at 6-8 h post-incubation,and viable counts gradually declined after 8 h of incubation.The correlation equation between OD 600 values and viable counts is y=24.659 x-1.076 1,R^2=0.996 7.TA01 strain was sensitive to penicillin,erythromycin,florfenicol and oxacillin,and resistant to ciprofloxacin,polymyxin B and clindamycin.According to the results of pathogenicity analysis,all the mice in 3.6×10^9 cfu/mouse group died within 48,and these dead mice exhibited acute pyaemia septica.Based on the Reed-Muench formula,it was calculated that LD 50 of TA01 strain was 1.137×10^8 cfu/mouse.Pathological examination showed obvious blue-stained bacteria clusters,accompanied by neutrophil infiltration.[Conclusions]TA01 strain was a virulent strain of Streptococcus suis type 2.Compared with Streptococcus strains which were isolated and reported in China,TA01 strain exhibited strong virulence and rapid proliferation.
基金supported by Grants (30070362, 30170135,30021004) the National Natural Science Foundationof China and Grants (KSCX2-SW-101C, STZ-00-23)the Chinese Academy of Sciences.
文摘The genes encoding type II DNA topoisomerases were investigated in Giardia lamblia genome, and a type IIA gene,GlTop 2 was identified. It is a single copy gene with a 4476 bp long ORF without intron. The deduced amino acid sequence shows strong homology to eukaryotic DNA Top 2. However, some distortions were found, such as six insertions in the ATPase domain and the central domain, a -100 aa longer central domain; a ~200 aa shorter C-terminal domain containing rich charged residues. These features revealed by comparing with Top 2 of the host, human, might be helpful in exploiting drug selectivity for antigiardial therapy. Phylogenetic analysis of eukaryotic enzymes showed that kinetoplastids, plants, fungi, and animals were monophyletic groups, and the animal and fungi lineages shared a more recent common ancestor than either did with the plant lineage; microsporidia grouped with fungi. However, unlike many previous phylogenetic analyses, the ''amitochondriate'' G. lamblia was not the earliest branch but diverged after mitochondriate kinetoplastids in our trees. Both the finding of typical eukaryotic type IIA topoisomerase and the phylogenetic analysis suggest G, lamblia is not possibly as primitive as was regarded before and might diverge after the acquisition of mitochondria. This is consistent with the recent discovery of mitochondrial remnant organelles in G. lamblia.
基金funded by 12th Five-Year Technology Support Program-key pastoral areas production of ecological life protection technology integration and demonstration topics-comprehensive prevention and control technology integration,innovation and application of cattle and sheep key epidemic disease(2012BAD13B06)Veterinary Medicine Discipline Program of Southwest University for Nationalities(2011XWD-S0906)
文摘[ Objective] In order to make out differences between drug resistance spectrum types of different animal sources of Salmonella. [ Meth- otis] Selenite cystine broth, Salmonella- Shigella genus agar medium, CHROMagar Salmonella chromogenic culture, Reveal Salmonella detection kit and molecular biology methods were used for isolation and identification of Salmonella from different animal feces samples. Antibacterialantimi- crobial susceptibility tests of 17 kinds of drugs such as enrofloxacin, apramycin and florfenicol were done on isolated strains with broth microdilution method, and test data was analysed with WHOnet 5.4 software. [ Results ] 699 feces samples from different animals were separated, and 53 strains of Salmonella were achieved with separation rate of 7.58%, among which those of yak, poultry, and pet sources were respectively 4.33%, 9.06% and 8.37%. [ Condusions] Separation rates and drug resistance spectrum types of different animal origin Salmonella varied greatly, among which separation rates and drug resistance spectrum types of yak source Salmonella were the lowest, there was little difference between separation rates of poultry and dog source Salmonella, however there were large differences on drug resistance spectrum types.
基金supported by the National Natural Science Foundation of China(No.U21B2062)the Natural Science Foundation of Hubei Province(No.2023AFB307)。
文摘Identification of reservoir types in deep carbonates has always been a great challenge due to complex logging responses caused by the heterogeneous scale and distribution of storage spaces.Traditional cross-plot analysis and empirical formula methods for identifying reservoir types using geophysical logging data have high uncertainty and low efficiency,which cannot accurately reflect the nonlinear relationship between reservoir types and logging data.Recently,the kernel Fisher discriminant analysis(KFD),a kernel-based machine learning technique,attracts attention in many fields because of its strong nonlinear processing ability.However,the overall performance of KFD model may be limited as a single kernel function cannot simultaneously extrapolate and interpolate well,especially for highly complex data cases.To address this issue,in this study,a mixed kernel Fisher discriminant analysis(MKFD)model was established and applied to identify reservoir types of the deep Sinian carbonates in central Sichuan Basin,China.The MKFD model was trained and tested with 453 datasets from 7 coring wells,utilizing GR,CAL,DEN,AC,CNL and RT logs as input variables.The particle swarm optimization(PSO)was adopted for hyper-parameter optimization of MKFD model.To evaluate the model performance,prediction results of MKFD were compared with those of basic-kernel based KFD,RF and SVM models.Subsequently,the built MKFD model was applied in a blind well test,and a variable importance analysis was conducted.The comparison and blind test results demonstrated that MKFD outperformed traditional KFD,RF and SVM in the identification of reservoir types,which provided higher accuracy and stronger generalization.The MKFD can therefore be a reliable method for identifying reservoir types of deep carbonates.
基金Supported by Key Project of Jiangsu Agri-animal Husbandry Vocational College(ZD201104)College Students'Innovation and Enterpreneurship Training Program of Jiangsu Province(201312806014Y)Special Fund for Fenghuang talents in Jiangsu Agri-animal Husbandry Vocational College
文摘In September 2011, an infectious disease suspected to be postweaning multisystemic wasting syndrome （PMWS） broke out in some pig farm in Taizhou. The inguinal lymph node, liver and lung tissues were collected and grinded into tissue suspension. The suspension was subjected to PCR detection, and the positive product was sequenced. The suspension of positive samples was filtered with 0.22 μm filter membrane, and the filtrate was inoculated onto PK15 cells. After five generations of blind passages, the cell viral liquid was collected and extracted for DNA, which was subjected to PCR detection and indirect immunofluorescence. The results showed that the isolate was porcine circovirus type 2 （PCV2） and designated as TAIZ110926. The target sequence was committed to NCBI with a serial number： KF039888.
基金This project was sponsored by the Nationnal Science Foundation(496742149),China.
文摘The results of geological research show that those phenomena such as surface geology,geomorphology,deep geophysical field,and time-space distribution of seismicities can be usedas the main seismogeological indicators to identify the newly-generated seismic rupture zone(NSRZ).According to their formation and evolution process,the NSRZs can be divided intothree types:pre-rupture-isolated,quasi-rupture-discontinuous and major-rupture-connected.In a pre-rupture-isolated NSRZ,the seismicity is dominated by medium-small earthquakes.In a quasi-rupture-discontinuous NSRZ,the frequency and intensity of strong earthquakesincrease and there may even be the largest earthquake to occur.A major-rupture-connectedNSRZ is the segment where rupture has entered the mature stage;in such a zone,theintensity and duration of seismic activity depend on the constitutive condition and regionalstress field in the zone.
基金Financial support from the National Natural Science Foundation of China (No. 40730422)the Priority Academic Program Development of Jiangsu Higher Education Institutions of Chinadata provided by Jurassic Project Department in Research Institute of Petroleum Exploration and Development of China are gratefully acknowledged
文摘The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing ratio of source-mixed gas. Besides, this research quantitatively investigated the natural gas generated by different types of organic matter. The results show that different ratios of source-mixed gas exist in the 6 oil-gas fields at the northern margin of Qaidam Basin. Among them, Mabei has the highest mixing ratio of coal-type gas, followed by Nanbaxian, Mahai, Lenghu-4, Lenghu-3 and Lenghu-5, with the ratios of coal-type gas 91%, 87%, 83%, 66%, 55% and 36%, respectively. Lenghu-3 and Lenghu-4 oil-gas fields were mainly filled by coal-type gas earlier. For Lenghu-3, the gas was mainly generated from low matured source rocks in lower Jurassic Series of Lengxi sub-sag. For Lenghu-4, the gas was mainly generated from humus-mature source rocks in lower Jurassic Series of the northern slope of Kunteyi sub-sag. Gas in Lenghu-5 was mainly later filled oil-type gas, which was generated from high matured sapropelics in lower Jurassic Series of Kunteyi sub-sag. Earlier filled coal-type gas was the main part of Mahai, Nanbaxian and Mabei oil-gas fields. Gas source of Mahai was mainly generated from high mature humics in lower Jurassic Series of Yibei sub-sag; for Nanbaxian, the gas was mainly generated from high matured humics in middle-lower Jurassic Series of Saishiteng sub-sag; for Mabei, the gas was mainly generated from humus-mature source rocks in middle Jurassic Series of Yuqia sub-sag.
基金supported by the National Natural Science Foundation of China(Nos.42177173,U23A20651 and 42130719)and the Outstanding Youth Science Fund Project of Sichuan Provincial Natural Science Foundation(No.2025NSFJQ0003)。
文摘Dynamic stress adjustment in deep-buried high geostress hard rock tunnels frequently triggers catastrophic failures such as rockbursts and collapses.While a comprehensive understanding of this process is critical for evaluating surrounding rock stability,its dynamic evolution are often overlooked in engineering practice.This study systematically summarizes a novel classification framework for stress adjustment types—stabilizing(two-zoned),shallow failure(three-zoned),and deep failure(four-zoned)—characterized by distinct stress adjustment stages.A dynamic interpretation technology system is developed based on microseismic monitoring,integrating key microseismic parameters(energy index EI,apparent stressσa,microseismic activity S),seismic source parameter space clustering,and microseismic paths.This approach enables precise identification of evolutionary stages,stress adjustment types,and failure precursors,thereby elucidating the intrinsic linkage between geomechanical processes(stress redistribution)and failure risks.The study establishes criteria and procedures for identifying stress adjustment types and their associated failure risks,which were successfully applied in the Grand Canyon Tunnel of the E-han Highway to detect 50 instances of disaster risks.The findings offer invaluable insights into understanding the evolution process of stress adjustment and pinpointing the disaster risks linked to hard rock in comparable high geostress tunnels.
