It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bit...It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bits with different design features exhibits significant differences in rock breaking effi-ciency and stability.This indicates that studying the compatibility between PDC bit and PDM before conducting drilling process is necessary.TheΦ215.9 mm wellbore condition in Longmaxi formation was taken as an example,the positive rotational speed and positive torque exerted byΦ197mm PDM with different number of lobes and pitch length were calculated,PDC bit with different cutting strategies were designed.Then finite element method(FEM)models considering PDM output parameters were established to study rock breaking process.Required weight on bit(WOB),required mechanical specific energy(MSE),reaction torque on bit(TOB),and vibration characteristics at near-bit position under the designed rate of penetration(ROP)were obtained.Research results showed that:(1)The energy required for PDC bit with certain design features breaking shale is not a constant value,but a value changes with rotational speed and positive torque exerted by different PDM.(2)The ability controlling vibration of PDM tends to stabilize when the number of lobes N and pitch length h exceeds 5 and 140 mm respectively in general conditions,Thus combination design parameters when N=5,h=140 mm were suggested to balance rock breaking efficiency and service life of drill strings.(3)Compared with other cutting strategies,when rock breaking pattern consist of“face to face”interaction and“point to point”interaction,both rock breaking efficiency and stability were higher.While when matched with this cutting strategy,N=8 and h=140/200 mm were recommended for PDM design instead of N=5 and h=140 mm obtained in most cases,which cloud minimize the loss of rock breaking efficiency and improve the axial/circumferential stability by 14.24%–17.23%and 24.93%–35.73%respectively.An integrated selection and design method of PDC bit and PDM was established and implemented,which revealed the rock breaking efficiency and stability patterns of different rock breaking tools combinations,providing theoretical support and suggestions for the integrated selection and design of PDC bits and PDM in Longmaxi formation.展开更多
Aeolian deposits from the deserts in northern China have been used for palaeoenvironmental research to understand aeolian sedimentology and its dynamic connection to past climate conditions. The Tengger Desert in Chin...Aeolian deposits from the deserts in northern China have been used for palaeoenvironmental research to understand aeolian sedimentology and its dynamic connection to past climate conditions. The Tengger Desert in China is sensitive to the waxing and waning of the monsoonal system. In response to past climate change, the southern margin of the Tengger Desert has evolved significantly since the last glacial period. However, previous attempts to date aeolian deposits in this region were mainly based on radiocarbon dating, which has problems when applied to aeolian deposits. Moreover, sedimentary records are limited. Accordingly, past aeolian activity in this desert remains poorly understood. In the present study, we dated sand samples from Gulang county at the southern margin of the Tengger Desert using optically stimulated luminescence (OSL) to understand the history of aeolian activity in this region. Our samples represented well-sorted aeolian sands and sandy loess. Aeolian sands are evidence of dune field buildup and sparse vegetation cover whereas sandy loess is evidence of improved stabilization of sand dunes resulting from ameliorated vegetation cover. Certain samples showed a decline in the equivalent dose (D<sub> e </sub>) values when successive integration intervals were applied, which resulted from unstable OSL signals from non-fast components in the initial part of the decay curve. In order to obtain reliable D<sub> e </sub> estimates, we investigated component-resolved and different background subtraction approaches, and compared the resultant D<sub> e </sub> estimates. We adopted the early background subtraction method to derive D<sub> e </sub> values. Luminescence chronologies and sedimentary records indicated that sand dunes accumulation occurred before 10 ka, and sandy loess developed between 9.5 and 7.6 ka when sand dunes were stabilized as a result of increased effective moisture levels. The transition between sand dune mobilization and stabilization emphasizes the significance of an effective moisture threshold in controlling aeolian activity. Mobilization of sand dunes at ~2.3 ka might be related to an increased aridity during the Late Holocene.展开更多
The first paradigm of plant breeding involves direct selection-based phenotypic observation,followed by predictive breeding using statistical models for quantitative traits constructed based on genetic experimental de...The first paradigm of plant breeding involves direct selection-based phenotypic observation,followed by predictive breeding using statistical models for quantitative traits constructed based on genetic experimental design and,more recently,by incorporation of molecular marker genotypes.However,plant performance or phenotype(P)is determined by the combined effects of genotype(G),envirotype(E),and genotype by environment interaction(GEI).Phenotypes can be predicted more precisely by training a model using data collected from multiple sources,including spatiotemporal omics(genomics,phenomics,and enviromics across time and space).Integration of 3D information profiles(G-P-E),each with multidimensionality,provides predictive breeding with both tremendous opportunities and great challenges.Here,we first review innovative technologies for predictive breeding.We then evaluate multidimensional information profiles that can be integrated with a predictive breeding strategy,particularly envirotypic data,which have largely been neglected in data collection and are nearly untouched in model construction.We propose a smart breeding scheme,integrated genomic-enviromic prediction(iGEP),as an extension of genomic prediction,using integrated multiomics information,big data technology,and artificial intelligence(mainly focused on machine and deep learning).We discuss how to implement iGEP,including spatiotemporal models,environmental indices,factorial and spatiotemporal structure of plant breeding data,and cross-species prediction.A strategy is then proposed for prediction-based crop redesign at both the macro(individual,population,and species)and micro(gene,metabolism,and network)scales.Finally,we provide perspectives on translating smart breeding into genetic gain through integrative breeding platforms and open-source breeding initiatives.We call for coordinated efforts in smart breeding through iGEP,institutional partnerships,and innovative technological support.展开更多
Objective：To assess the efficacy of Chinese medicine（CM） on patients with pancreatic cancer（PC） in a retrospective population-based study.Methods：Between January 1,2013,and August 30,2016,according to whether re...Objective：To assess the efficacy of Chinese medicine（CM） on patients with pancreatic cancer（PC） in a retrospective population-based study.Methods：Between January 1,2013,and August 30,2016,according to whether received Western medicine treatment,the patients were included into either integrative medicine（IM） group or CM group.All enrolled patients were orally administrated with Gexia Zhuyu Decoction（膈下逐瘀汤） or Liujun Ermu Decoction（六君二母汤） by syndrome differentiation,twice a day,last for at least 2 months.The primary end point was overall survival（OS）.Results：A total of 174 patients with PC were enrolled in this study.In stage Ⅰ/Ⅱ,the median OS was 20.5 months in the IM group [95% confidence interval（CI）,12.499 to 28.501] and 11.17 months in the CM group（95% CI,5.160 to 17.180,P=0.015）.The 1-and 2-year survival rates for the two groups were 47.0%,40.0% and 21.0%,21.0%,respectively.In stage Ⅲ/Ⅳ,median OS was 13.53 months（95% CI,8.665 to 18.395） in the IM group versus 6.4 months（95% CI,0.00 to 15.682） in the CM group,respectively（P=0.32）.The 1-and 2-year survival rate for the IM and CM groups were 27.0%,7.0% and 20.0%,2.0%,respectively.Conclusions：Intervention of CM contributes to the different survival benefits for PC in different stages.Multimodality treatment might be a promising strategy for PC patients in early stage.While,in advanced stage,CM might be an alternative candidate for PC patients.展开更多
基金CNPC(China National Petroleum Corporation)-SWPU(South-west Petroleum University)Innovation Consortium Project:Optimization research on drilling method and technology for complex formations in deep wells,Project ID:2020CX040103,2020/01-2025/12Essential Research and Development Plan by Department of Science and Technology in Sichuan Province(International Science and Technology Innovation Cooperation/Hong Kong Macao Taiwan Science and Technology Innovation Cooperation Project):Mechanism and Key Technologies of CO_(2) Accelerating Mineralization and Storage in Basalt Strata,Project ID:2023YFH0005,2023/01-2025/12Essential Research and Development Plan by Department of Science and Technology in Sichuan Province:Research on Geological Storage and Disaster Prevention of CO_(2)in Deep Saline Water Layer,Project ID:2022YFSY0007,2023/01-2025/12.
文摘It has been found that the rock breaking tools combination of positive displacement motors(PDM)with different output parameters(positive rotational speed and positive torque)and polycrystalline diamond compact(PDC)bits with different design features exhibits significant differences in rock breaking effi-ciency and stability.This indicates that studying the compatibility between PDC bit and PDM before conducting drilling process is necessary.TheΦ215.9 mm wellbore condition in Longmaxi formation was taken as an example,the positive rotational speed and positive torque exerted byΦ197mm PDM with different number of lobes and pitch length were calculated,PDC bit with different cutting strategies were designed.Then finite element method(FEM)models considering PDM output parameters were established to study rock breaking process.Required weight on bit(WOB),required mechanical specific energy(MSE),reaction torque on bit(TOB),and vibration characteristics at near-bit position under the designed rate of penetration(ROP)were obtained.Research results showed that:(1)The energy required for PDC bit with certain design features breaking shale is not a constant value,but a value changes with rotational speed and positive torque exerted by different PDM.(2)The ability controlling vibration of PDM tends to stabilize when the number of lobes N and pitch length h exceeds 5 and 140 mm respectively in general conditions,Thus combination design parameters when N=5,h=140 mm were suggested to balance rock breaking efficiency and service life of drill strings.(3)Compared with other cutting strategies,when rock breaking pattern consist of“face to face”interaction and“point to point”interaction,both rock breaking efficiency and stability were higher.While when matched with this cutting strategy,N=8 and h=140/200 mm were recommended for PDM design instead of N=5 and h=140 mm obtained in most cases,which cloud minimize the loss of rock breaking efficiency and improve the axial/circumferential stability by 14.24%–17.23%and 24.93%–35.73%respectively.An integrated selection and design method of PDC bit and PDM was established and implemented,which revealed the rock breaking efficiency and stability patterns of different rock breaking tools combinations,providing theoretical support and suggestions for the integrated selection and design of PDC bits and PDM in Longmaxi formation.
基金funded by the National Basic Research Program of China(2013CB956000,2012CB426501)
文摘Aeolian deposits from the deserts in northern China have been used for palaeoenvironmental research to understand aeolian sedimentology and its dynamic connection to past climate conditions. The Tengger Desert in China is sensitive to the waxing and waning of the monsoonal system. In response to past climate change, the southern margin of the Tengger Desert has evolved significantly since the last glacial period. However, previous attempts to date aeolian deposits in this region were mainly based on radiocarbon dating, which has problems when applied to aeolian deposits. Moreover, sedimentary records are limited. Accordingly, past aeolian activity in this desert remains poorly understood. In the present study, we dated sand samples from Gulang county at the southern margin of the Tengger Desert using optically stimulated luminescence (OSL) to understand the history of aeolian activity in this region. Our samples represented well-sorted aeolian sands and sandy loess. Aeolian sands are evidence of dune field buildup and sparse vegetation cover whereas sandy loess is evidence of improved stabilization of sand dunes resulting from ameliorated vegetation cover. Certain samples showed a decline in the equivalent dose (D<sub> e </sub>) values when successive integration intervals were applied, which resulted from unstable OSL signals from non-fast components in the initial part of the decay curve. In order to obtain reliable D<sub> e </sub> estimates, we investigated component-resolved and different background subtraction approaches, and compared the resultant D<sub> e </sub> estimates. We adopted the early background subtraction method to derive D<sub> e </sub> values. Luminescence chronologies and sedimentary records indicated that sand dunes accumulation occurred before 10 ka, and sandy loess developed between 9.5 and 7.6 ka when sand dunes were stabilized as a result of increased effective moisture levels. The transition between sand dune mobilization and stabilization emphasizes the significance of an effective moisture threshold in controlling aeolian activity. Mobilization of sand dunes at ~2.3 ka might be related to an increased aridity during the Late Holocene.
基金National Key Research and Development Program of China(2016YFD0101803)Central Public-interest Scientific Institution Basal Research Fund(Y2020PT20)+5 种基金Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-XTCX2016009)Shijiazhuang Science and Technology Incubation Program(191540089A)Hebei Innovation Capability Enhancement Project(19962911D)Project of Hainan Yazhou Bay Seed Laboratory(B21HJ0223)Department of Science and Technology of Ninxia Project(NXNYYZ202001)Research activities at CIMMYT were supported by the Bill and Melinda Gates Foundation and the CGIAR Research Program MAIZE.
文摘The first paradigm of plant breeding involves direct selection-based phenotypic observation,followed by predictive breeding using statistical models for quantitative traits constructed based on genetic experimental design and,more recently,by incorporation of molecular marker genotypes.However,plant performance or phenotype(P)is determined by the combined effects of genotype(G),envirotype(E),and genotype by environment interaction(GEI).Phenotypes can be predicted more precisely by training a model using data collected from multiple sources,including spatiotemporal omics(genomics,phenomics,and enviromics across time and space).Integration of 3D information profiles(G-P-E),each with multidimensionality,provides predictive breeding with both tremendous opportunities and great challenges.Here,we first review innovative technologies for predictive breeding.We then evaluate multidimensional information profiles that can be integrated with a predictive breeding strategy,particularly envirotypic data,which have largely been neglected in data collection and are nearly untouched in model construction.We propose a smart breeding scheme,integrated genomic-enviromic prediction(iGEP),as an extension of genomic prediction,using integrated multiomics information,big data technology,and artificial intelligence(mainly focused on machine and deep learning).We discuss how to implement iGEP,including spatiotemporal models,environmental indices,factorial and spatiotemporal structure of plant breeding data,and cross-species prediction.A strategy is then proposed for prediction-based crop redesign at both the macro(individual,population,and species)and micro(gene,metabolism,and network)scales.Finally,we provide perspectives on translating smart breeding into genetic gain through integrative breeding platforms and open-source breeding initiatives.We call for coordinated efforts in smart breeding through iGEP,institutional partnerships,and innovative technological support.
基金Supported by the National Natural Science Foundation of China(No.81673797)
文摘Objective：To assess the efficacy of Chinese medicine（CM） on patients with pancreatic cancer（PC） in a retrospective population-based study.Methods：Between January 1,2013,and August 30,2016,according to whether received Western medicine treatment,the patients were included into either integrative medicine（IM） group or CM group.All enrolled patients were orally administrated with Gexia Zhuyu Decoction（膈下逐瘀汤） or Liujun Ermu Decoction（六君二母汤） by syndrome differentiation,twice a day,last for at least 2 months.The primary end point was overall survival（OS）.Results：A total of 174 patients with PC were enrolled in this study.In stage Ⅰ/Ⅱ,the median OS was 20.5 months in the IM group [95% confidence interval（CI）,12.499 to 28.501] and 11.17 months in the CM group（95% CI,5.160 to 17.180,P=0.015）.The 1-and 2-year survival rates for the two groups were 47.0%,40.0% and 21.0%,21.0%,respectively.In stage Ⅲ/Ⅳ,median OS was 13.53 months（95% CI,8.665 to 18.395） in the IM group versus 6.4 months（95% CI,0.00 to 15.682） in the CM group,respectively（P=0.32）.The 1-and 2-year survival rate for the IM and CM groups were 27.0%,7.0% and 20.0%,2.0%,respectively.Conclusions：Intervention of CM contributes to the different survival benefits for PC in different stages.Multimodality treatment might be a promising strategy for PC patients in early stage.While,in advanced stage,CM might be an alternative candidate for PC patients.
