The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is close...The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.展开更多
Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids su er from p...Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids su er from poor tolerance to high temperature and high salinity. Thermoviscosifying polymers(TVP) whose aqueous solution shows viscosity increase upon increasing temperature and salt concentration have received considerable attention recently, which is promising for utilization in fracturing fluids to overcome these problems. In this work, both the salt-induced viscosifying property and mechanism of a TVP solution were investigated and the performance of TVP used as fracturing fluid based on the conditions of the Jianghan inter-salt shale oil reservoir in China was evaluated. It is found that the salt-induced viscosifying property of the TVP solution decreases with temperature and shear rate, but increases with polymer concentration. The number of intermolecular hydrophobic domains increases with the salt concentration contributing to the strengthening of a 3D network structure, which results in an increase in viscosity. In addition, the TVP fracturing fluid formulated with saturated brine exhibits excellent temperature and shear resistance, sand-suspending performance, and gel-breaking performance. Its viscosity remains above50 m Pa s after being sheared for 1 h even at a high temperature of 140 °C and the sand-suspending stability can be maintained for more than 1 week at 100 °C. Furthermore, the fracturing fluid can be easily broken down within 12h using 0.2 wt%–0.3 wt% potassium persulfate without residue.展开更多
In the southwestern margin of the Ordos Basin,uranium mineralization is primarily hosted by predominantly oxidative red clastic formations in the Lower Cretaceous.The main target layers for uranium exploration are the...In the southwestern margin of the Ordos Basin,uranium mineralization is primarily hosted by predominantly oxidative red clastic formations in the Lower Cretaceous.The main target layers for uranium exploration are the Madongshan and Liwaxia formations of the Liupanshan Group,followed by the Jingchuan Formation of the Zhidan Group.The host rocks(medium-fine feldspar quartz sandstone),which are bleached to a light grayish white color,contain a minor organic matter component and pyrite.Uranium mineralization changes from surficial infiltration or phreatic oxidation in the upper part to interlayer oxidation in the lower part.Uranium ore bodies are mostly lenticular or tabular in shape,locally shaped like crescent rolls.Individual ore bodies are typically small and shallow.Uranium predominantly manifests as pitchblende and coffinite.Coffinite is usually short and columnar or granular in habit,whereas pitchblende occurs as an irregular colloidal covering on the surface or in fissures of ferric oxide,silicate,clay or carbonate.Secondary uranium minerals are torbernite,uranophane,and uranopilite.Minerals associated with uranium are mainly pyrite,chalcopyrite and,to a minor extent,arsenopyrite and fluorite.The associated elements are Mo,V,Se,Co,Ni,and Mn,the host sandstone being high in Cu and Ba.Overall,the red clastic formations in the southwestern margin of the Ordos Basin are characterized by’five multiples but one low’which means multiple target layers,multiple stages of mineralization,multiple ore body shapes,multiple kinds of uranium minerals,multiple associated elements,but low organic matter.This implies an overall complex uranium metallogenic environment and mineralization process.It is recommended that future uranium exploration should take into consideration regional metallogenic conditions and mineralization features,with target layers in the wide-smooth synclinal slope being focused on.Most uranium deposits are small to medium in size,and the main type of uranium mineralization can vary by target layer.展开更多
,d,l-a-Tocopherol (vitamin E) isfound to be synthesized by condensingtrimethylhydroquinone with isophytol catalyzed by heteropoly acids (HPA) H3:PW12O40 andH3PMo12O40 at room temperature. These HPA are efficient cata...,d,l-a-Tocopherol (vitamin E) isfound to be synthesized by condensingtrimethylhydroquinone with isophytol catalyzed by heteropoly acids (HPA) H3:PW12O40 andH3PMo12O40 at room temperature. These HPA are efficient catalysts for the synthesis of d l-a-Tocopherol and can easily be separated from the reaction mixture and roused,展开更多
A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics, where fluids are described by a molecular dynamics （MD） in one domain and by the Navier-Stokes （NS） equations in anothe...A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics, where fluids are described by a molecular dynamics （MD） in one domain and by the Navier-Stokes （NS） equations in another domain. In order to ensure the continuity of momentum flux, the continuum and molecular dynamics in the overlap domain are coupled through a constrained particle dynamics. The constrained particle dynamics is constructed with a virtual damping force and a virtual added mass force. The sudden-start Couette flows with either non-slip or slip boundary condition are used to test the hybrid method. It is shown that the results obtained are quantitatively in agreement with the analytical solutions under the non-slip boundary conditions and the full MD simulations under the slip bound- ary conditions.展开更多
Objective Curcumin is extracted from the turmeric plant （Curcuma longa Linn.） and is widely used as a food additive and traditional medicine. The present study investigated the activity of curcumin against staurospo...Objective Curcumin is extracted from the turmeric plant （Curcuma longa Linn.） and is widely used as a food additive and traditional medicine. The present study investigated the activity of curcumin against staurosporine （STS） toxicity in cell culture. Methods Rat hippocampal neurons in primary culture were exposed to STS （20 μmol/L） and treated with curcumin （20 μmol/L）. Cell viability was tested by MTT assay and reactive oxygen species （ROS） were measured using the MitoSOX red mitochondrial superoxide indicator. Western blot was used to assess changes in the levels of caspase-3 （Csp3）, heat shock protein 70 （Hsp70） and Akt. Results The results showed that curcumin protects against STS-induced cytotoxicity in rat hippocampal neurons. Csp3, Hsp70, Akt and ROS activation may be involved in this protection. Conclusion Curcumin could be a potential drug for combination with STS in cancer treatment to reduce the unwanted cytotoxicity of STS.展开更多
Powered by the Internet and the ever-increasing level of informatization, the cyberspace has become increasingly complex and its security situation has become increasingly grim, which requires new adaptive and collabo...Powered by the Internet and the ever-increasing level of informatization, the cyberspace has become increasingly complex and its security situation has become increasingly grim, which requires new adaptive and collaborative defense technologies. In this paper, we introduced an extended interactive multi-agent decision model for decentralized cyber defense. Based on the significant advantages of the cooperative multi-agent decision-making, the decentralized interactive decision model DI-MDPs and the corresponding interaction and retrieval algorithms are proposed. Then, we analyzed the interactive decision by the calculation and update processes of three matrices, the stability and evolutionary equilibrium of the proposed model are also analyzed. Finally, we evaluated the performance of the proposed algorithms based on open data sets and standard test environments, the experimental results shown that the proposed work will be more applicable in cyber defense.展开更多
Theileria is a tick-borne intracellular protozoan that typically parasitizes erythrocytes,lymphocytes,and macrophages and causes acute clinical symptoms in host animals,including high fever,anemia,jaundice,and swellin...Theileria is a tick-borne intracellular protozoan that typically parasitizes erythrocytes,lymphocytes,and macrophages and causes acute clinical symptoms in host animals,including high fever,anemia,jaundice,and swelling of superficial lymph nodes[1].Theileriosis can lead to high mortality rates,and its rising global prevalence has resulted in significant economic losses to livestock husbandry and the national economy[2].展开更多
BACKGROUND The thoracic wall lesions,particularly chest wall tuberculosis,and chest wall tumors and other pyogenic wall and actinomycetes infections,almost always present as a diagnostic challenge.AIM To explore the v...BACKGROUND The thoracic wall lesions,particularly chest wall tuberculosis,and chest wall tumors and other pyogenic wall and actinomycetes infections,almost always present as a diagnostic challenge.AIM To explore the value of ultrasound-guided biopsy combined with the Xpert Mycobacterium tuberculosis/resistance to rifampin(MTB/RIF)assay to diagnose chest wall tuberculosis.METHODS We performed a retrospective study of patients with chest wall lesions from March 2018 to March 2021.All patients received the ultrasound-guided biopsy for pathology examination,acid-fast Bacillus staining,mycobacterial culture,and Xpert MTB/RIF analysis.The sensitivity,specificity,and area under the curve(AUC)were calculated for these diagnostic tests,either individually or combined.Rifampicin resistance results were compared between the mycobacterial culture and the Xpert MTB/RIF assay.RESULTS In 31 patients with the chest wall lesion biopsy,22 patients were diagnosed with chest wall tuberculosis.Of them,3,6,and 21 patients tested positive for mycobacterial culture,acid-fast stain,and Xpert MTB/RIF assay,respectively.The rifampicin resistance results of the 3 culture-positive patients were consistent with their Xpert MTB/RIF assay results.When considering the sensitivity,specificity,and AUC value,the Xpert MTB/RIF assay(95.5%,88.9%,and 0.92,respectively)was a better choice than the acid-fast Bacillus stain(27.3%,100.0%,and 0.64,respectively)and mycobacterial culture(13.6%,100.0%,0.57,respectively).No complications were reported during the procedure.CONCLUSION Ultrasound guided biopsy combined with Xpert MTB/RIF has high value in the diagnosis of chest wall tuberculosis,and can also detect rifampicin resistance.展开更多
基金financiallysupported by the Excellent Young Fund of Sinopec Petroleum Exploration and Production Research Institute(Grant No.YK2024009)the National Natural Science Foundation of China(Grant Nos.U23B6004 and 51925405).
文摘The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.
基金financial support from State Energy Center for Shale Oil Research and Development(Grant No.G5800-17-ZS-KFNY008)
文摘Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids su er from poor tolerance to high temperature and high salinity. Thermoviscosifying polymers(TVP) whose aqueous solution shows viscosity increase upon increasing temperature and salt concentration have received considerable attention recently, which is promising for utilization in fracturing fluids to overcome these problems. In this work, both the salt-induced viscosifying property and mechanism of a TVP solution were investigated and the performance of TVP used as fracturing fluid based on the conditions of the Jianghan inter-salt shale oil reservoir in China was evaluated. It is found that the salt-induced viscosifying property of the TVP solution decreases with temperature and shear rate, but increases with polymer concentration. The number of intermolecular hydrophobic domains increases with the salt concentration contributing to the strengthening of a 3D network structure, which results in an increase in viscosity. In addition, the TVP fracturing fluid formulated with saturated brine exhibits excellent temperature and shear resistance, sand-suspending performance, and gel-breaking performance. Its viscosity remains above50 m Pa s after being sheared for 1 h even at a high temperature of 140 °C and the sand-suspending stability can be maintained for more than 1 week at 100 °C. Furthermore, the fracturing fluid can be easily broken down within 12h using 0.2 wt%–0.3 wt% potassium persulfate without residue.
基金jointly supported by Key Factors Identification and Targets Delineation of Sandstone Type Uranium Deposits in the Southern Ordos Basin(CNNC Integrated R&D Project,Code:Geo LTD1601–3)Scientific Research in Production Project issued by the Bureau of Geology,CNNC(Code:201902-7)the Chinese Geological Survey project(Code:DD201908135)。
文摘In the southwestern margin of the Ordos Basin,uranium mineralization is primarily hosted by predominantly oxidative red clastic formations in the Lower Cretaceous.The main target layers for uranium exploration are the Madongshan and Liwaxia formations of the Liupanshan Group,followed by the Jingchuan Formation of the Zhidan Group.The host rocks(medium-fine feldspar quartz sandstone),which are bleached to a light grayish white color,contain a minor organic matter component and pyrite.Uranium mineralization changes from surficial infiltration or phreatic oxidation in the upper part to interlayer oxidation in the lower part.Uranium ore bodies are mostly lenticular or tabular in shape,locally shaped like crescent rolls.Individual ore bodies are typically small and shallow.Uranium predominantly manifests as pitchblende and coffinite.Coffinite is usually short and columnar or granular in habit,whereas pitchblende occurs as an irregular colloidal covering on the surface or in fissures of ferric oxide,silicate,clay or carbonate.Secondary uranium minerals are torbernite,uranophane,and uranopilite.Minerals associated with uranium are mainly pyrite,chalcopyrite and,to a minor extent,arsenopyrite and fluorite.The associated elements are Mo,V,Se,Co,Ni,and Mn,the host sandstone being high in Cu and Ba.Overall,the red clastic formations in the southwestern margin of the Ordos Basin are characterized by’five multiples but one low’which means multiple target layers,multiple stages of mineralization,multiple ore body shapes,multiple kinds of uranium minerals,multiple associated elements,but low organic matter.This implies an overall complex uranium metallogenic environment and mineralization process.It is recommended that future uranium exploration should take into consideration regional metallogenic conditions and mineralization features,with target layers in the wide-smooth synclinal slope being focused on.Most uranium deposits are small to medium in size,and the main type of uranium mineralization can vary by target layer.
文摘,d,l-a-Tocopherol (vitamin E) isfound to be synthesized by condensingtrimethylhydroquinone with isophytol catalyzed by heteropoly acids (HPA) H3:PW12O40 andH3PMo12O40 at room temperature. These HPA are efficient catalysts for the synthesis of d l-a-Tocopherol and can easily be separated from the reaction mixture and roused,
基金The project supported by Chinese Academy of Sciences under the innovative project "Multi-scale modelling and simulation in complex system" (KJCX-SW-L08)National Natural Science Foundation of China (10325211)
文摘A hybrid method of continuum and particle dynamics is developed for micro- and nano-fluidics, where fluids are described by a molecular dynamics （MD） in one domain and by the Navier-Stokes （NS） equations in another domain. In order to ensure the continuity of momentum flux, the continuum and molecular dynamics in the overlap domain are coupled through a constrained particle dynamics. The constrained particle dynamics is constructed with a virtual damping force and a virtual added mass force. The sudden-start Couette flows with either non-slip or slip boundary condition are used to test the hybrid method. It is shown that the results obtained are quantitatively in agreement with the analytical solutions under the non-slip boundary conditions and the full MD simulations under the slip bound- ary conditions.
基金supported by the National Basic Research Development Program of China(2009CB941301)the National Natural Science Foundation of China (91132718, 30701138)+3 种基金the Peking University President Research Grantthe Ministry of Education Recruiting Research Grantthe Fundamental Research Funds for the Central Universities of China (1112KYZY41)the "985 Project" of Minzu University, China (MUC98504-14)
文摘Objective Curcumin is extracted from the turmeric plant （Curcuma longa Linn.） and is widely used as a food additive and traditional medicine. The present study investigated the activity of curcumin against staurosporine （STS） toxicity in cell culture. Methods Rat hippocampal neurons in primary culture were exposed to STS （20 μmol/L） and treated with curcumin （20 μmol/L）. Cell viability was tested by MTT assay and reactive oxygen species （ROS） were measured using the MitoSOX red mitochondrial superoxide indicator. Western blot was used to assess changes in the levels of caspase-3 （Csp3）, heat shock protein 70 （Hsp70） and Akt. Results The results showed that curcumin protects against STS-induced cytotoxicity in rat hippocampal neurons. Csp3, Hsp70, Akt and ROS activation may be involved in this protection. Conclusion Curcumin could be a potential drug for combination with STS in cancer treatment to reduce the unwanted cytotoxicity of STS.
基金financially supported by the National Natural Science Foundation of China (No. 62106060)in part by the Beijing Natural Science Foundation (No. 4214061)
文摘Powered by the Internet and the ever-increasing level of informatization, the cyberspace has become increasingly complex and its security situation has become increasingly grim, which requires new adaptive and collaborative defense technologies. In this paper, we introduced an extended interactive multi-agent decision model for decentralized cyber defense. Based on the significant advantages of the cooperative multi-agent decision-making, the decentralized interactive decision model DI-MDPs and the corresponding interaction and retrieval algorithms are proposed. Then, we analyzed the interactive decision by the calculation and update processes of three matrices, the stability and evolutionary equilibrium of the proposed model are also analyzed. Finally, we evaluated the performance of the proposed algorithms based on open data sets and standard test environments, the experimental results shown that the proposed work will be more applicable in cyber defense.
基金supported by the Shanxi Province Basic Research Program(Grant Nos.202303021221180,20210302124230,and 20210302124299)the Changzhi Medical College Doctoral Research Fund(BS202121)the Shanxi Province Innovation and Entrepreneurship Plan Project for College Students(20230868)。
文摘Theileria is a tick-borne intracellular protozoan that typically parasitizes erythrocytes,lymphocytes,and macrophages and causes acute clinical symptoms in host animals,including high fever,anemia,jaundice,and swelling of superficial lymph nodes[1].Theileriosis can lead to high mortality rates,and its rising global prevalence has resulted in significant economic losses to livestock husbandry and the national economy[2].
文摘BACKGROUND The thoracic wall lesions,particularly chest wall tuberculosis,and chest wall tumors and other pyogenic wall and actinomycetes infections,almost always present as a diagnostic challenge.AIM To explore the value of ultrasound-guided biopsy combined with the Xpert Mycobacterium tuberculosis/resistance to rifampin(MTB/RIF)assay to diagnose chest wall tuberculosis.METHODS We performed a retrospective study of patients with chest wall lesions from March 2018 to March 2021.All patients received the ultrasound-guided biopsy for pathology examination,acid-fast Bacillus staining,mycobacterial culture,and Xpert MTB/RIF analysis.The sensitivity,specificity,and area under the curve(AUC)were calculated for these diagnostic tests,either individually or combined.Rifampicin resistance results were compared between the mycobacterial culture and the Xpert MTB/RIF assay.RESULTS In 31 patients with the chest wall lesion biopsy,22 patients were diagnosed with chest wall tuberculosis.Of them,3,6,and 21 patients tested positive for mycobacterial culture,acid-fast stain,and Xpert MTB/RIF assay,respectively.The rifampicin resistance results of the 3 culture-positive patients were consistent with their Xpert MTB/RIF assay results.When considering the sensitivity,specificity,and AUC value,the Xpert MTB/RIF assay(95.5%,88.9%,and 0.92,respectively)was a better choice than the acid-fast Bacillus stain(27.3%,100.0%,and 0.64,respectively)and mycobacterial culture(13.6%,100.0%,0.57,respectively).No complications were reported during the procedure.CONCLUSION Ultrasound guided biopsy combined with Xpert MTB/RIF has high value in the diagnosis of chest wall tuberculosis,and can also detect rifampicin resistance.
