The effect of intermediate stress(in situ tunnel axial)on a strainburst is studied with a threedimensional(3D)bonded block distinct element method(DEM).A series of simulations of strainbursts under true triaxial in si...The effect of intermediate stress(in situ tunnel axial)on a strainburst is studied with a threedimensional(3D)bonded block distinct element method(DEM).A series of simulations of strainbursts under true triaxial in situ stress conditions(i.e.high tangential stress,moderate intermediate stress and low radial stress)of near-boundary rock masses are performed.Compared with the experimental results,the DEM model is able to capture the stress-strain response,failure pattern and energy balance of strainbursts.The fracturing processes of strainbursts are also numerically reproduced.Numerical results show that,as the intermediate stress increases:(1)The peak strain of strainbursts increases,the yield stress increases,the rock strength increases linearly,and the ratio of yield stress to rock strength decreases,indicating that the precursory information on strainbursts is enhanced;(2)Tensile and shear cracks increase significantly,and slabbing and bending of rock plates are more pronounced;and(3)The stored elastic strain energy and dissipated energy increase linearly,whereas the kinetic energy of the ejected rock fragments increases approximately exponentially,implying an increase in strainburst intensity.By comparing the experimental and numerical results,the effect of intermediate stress on the rock strength of strainbursts is discussed in order to address three key issues.Then,the Mogi criterion is applied to construct new strength criteria for strainbursts by converting the one-face free true triaxial stress state of a strainburst to its equivalent true triaxial stress state.In summary,the effect of intermediate stress on strainbursts is a double-edged sword that can enhance the rock strength and the precursory information of a strainburst,but also increase its intensity.展开更多
Strainbursts induced by cyclic disturbance with low frequency(termed as cyclicinduced strainbursts)are major dynamic disasters during deep excavation and mining.There is currently no quantitative criterion available f...Strainbursts induced by cyclic disturbance with low frequency(termed as cyclicinduced strainbursts)are major dynamic disasters during deep excavation and mining.There is currently no quantitative criterion available for the prediction of such disastrous events.In this study,based on true triaxial experiments,we analyzed the deformation characteristics,established two novel strain criteria for the cyclic-induced strainbursts,and explained the physical meaning of these criteria.Characteristic strains for the cyclic-induced strainbursts were defined,including the control strain ε_(ctr),the strain caused by the combined dynamic and static loading ε_(sd),and the ultimate strain ε_(u) after strainbursts.As indicated by the results,the deformation evolution of the cyclic-induced strainbursts shows remarkable fatigue characteristics,which resemble that of rock subjected to cyclic loading and unloading.In other words,there are three stages during deformation evolution,namely,initial rapid growth,uniform velocity growth after several periods of disturbance,and sudden sharp growth preceding the burst.The ultimate strain ε_(u) is insensitive to the tangential static stress and disturbance amplitude,but it changes nonlinearly with disturbance frequency.From the perspective of deformation,the occurrence of a cyclic-induced strainburst is controlled by the control strainε_(ctr).Thus,a control strain criterion is proposed;that is,when the stain ε_(sd) is larger than the control strain ε_(ctr),a strainburst will be induced by cyclic disturbance.Moreover,based on the statistical results,a strain ratio criterion is proposed;that is,when the strain ratio ε_(sd)/ε_(u) is greater than 30%,a cyclic-induced strainburst will be induced.展开更多
An effective approach is proposed for 3D urban scene reconstruction in the form of point cloud with semantic labeling. Starting from high resolution oblique aerial images,our approach proceeds through three main stage...An effective approach is proposed for 3D urban scene reconstruction in the form of point cloud with semantic labeling. Starting from high resolution oblique aerial images,our approach proceeds through three main stages: geographic reconstruction, geometrical reconstruction and semantic reconstruction. The absolute position and orientation of all the cameras relative to the real world are recovered in the geographic reconstruction stage. Then, in the geometrical reconstruction stage,an improved multi-view stereo matching method is employed to produce 3D dense points with color and normal information by taking into account the prior knowledge of aerial imagery.Finally the point cloud is classified into three classes(building,vegetation, and ground) by a rule-based hierarchical approach in the semantic reconstruction step. Experiments on complex urban scene show that our proposed 3-stage approach could generate reasonable reconstruction result robustly and efficiently.By comparing our final semantic reconstruction result with the manually labeled ground truth, classification accuracies from86.75% to 93.02% are obtained.展开更多
A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electr...A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.展开更多
Populus euphratica and Populuspruinosa, sister species in the Turanga Section (Salicaceae), growing in semi-arid saline areas are known for their high salinity tolerance. In this study, by combining growth level wit...Populus euphratica and Populuspruinosa, sister species in the Turanga Section (Salicaceae), growing in semi-arid saline areas are known for their high salinity tolerance. In this study, by combining growth level with Na+ and K+ contents, the expression level of vacuolar Na+/H+ antiporters was investigated for NaCl-induced changes in P. euphratica and t3. pru- inosa calli. Compared to R euphratica, P. pruinosa calli grew well in 200 mM NaC1 stress from 14. to 21 days. Increasing the stressed time caused an increase in Na+ content concomitant with a decrease in K+ content in P. euphratica calli, whereas, with the presence of 200 mM NaCI, K+ content has a less increase in 14 and 21 days than in 7 days which was detected in R pruinosa calli. The transcript levels of six genes coding for NHX-type Na+/H+ antiporters suggest that vacuolar NHX1-NHX6 antiporters play important roles in responding to salt stress in R pruinosa. Our data suggest that there exists a higher salt tolerance for P. pruinosa than P. euphratica at the cellular level, Na+ avoidance or accumulation is observed in cellular compartments, and that expression of NHX antiporters is linked to the accumulator phenotype.展开更多
This paper introduces the establishment of deep underground infrastructure for science and engineering research.First,the representative deep underground research laboratories and facilities in the world and their fun...This paper introduces the establishment of deep underground infrastructure for science and engineering research.First,the representative deep underground research laboratories and facilities in the world and their functions were summarized and reviewed.Then,the plan and service target of China Yulong Lake Laboratory were proposed for the storage of resources and energy,as well as the sealing of hazardous waste in deep underground space.On this basis,this paper reveals how the facility addresses its key scientific issue on“The law of fluid matter migration in deep underground space”and engineering significance.Finally,the construction progress of the facility components was demonstrated in details.As is hoped,this paper would provide useful reference to the deep underground research community;meanwhile,international collaboration on deep underground research is highly welcome.展开更多
Insertion sequences(ISs)exist widely in bacterial genomes,but their roles in the evolution of bacterial antiphage defense remain to be clarified.Here,we report that,under the pressure of phage infection,the IS1o96 tra...Insertion sequences(ISs)exist widely in bacterial genomes,but their roles in the evolution of bacterial antiphage defense remain to be clarified.Here,we report that,under the pressure of phage infection,the IS1o96 transposition of Mycobacterium smegmatis into the Isr2 gene can occur at high frequencies,which endows the mutant mycobacterium with a broad-spectrum antiphage ability.Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related genes.The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium,thus defending against phage infection.Strikingly,a phage that has evolved mutations in two tail-filament genes can re-escape from the Isr2 inactivation-triggered host defense.This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by Is transposition and provided insight into the natural evolution of bacterial antiphage defense.展开更多
Computer assisted movement tracking was used to characterize the motility of two marine microalgae, lsochrysis galbana and Tetraselmis chui, and to investigate the toxicity of Cu, Pb, and Cd on motile percentage, curv...Computer assisted movement tracking was used to characterize the motility of two marine microalgae, lsochrysis galbana and Tetraselmis chui, and to investigate the toxicity of Cu, Pb, and Cd on motile percentage, curvilinear velocity, average path velocity, straight line velocity, linearity, straightness, and wobble. Except for motile percentage, all other motility parameters differed significantly between L galbana and T. chui. Based on relative motile percentage data, the median effective concentration (ECs0) of Cu on the motility of L galbana and T. chui was 31.4 and 1.3 gmol/L, respectively, while for Pb it was 37.8 and 10.9 ~tmol/L and for Cd it was 12 1.6 and 37.8 ~tmol/L, respectively. Compared to L galbana, T. chui was more sensitive to all tested metals. The toxic effect of the heavy metals on motility exhibited the following decreasing order for both species: Cu 〉 Pb 〉 Cd. Our results indicate that L galbana and T. chui motility is sensitive to heavy metals and can be used as an indicator for toxicology bioassays.展开更多
Protein phosphorylation is one of the most important post-translational modifications.It is an active research area to study phosphoproteomics for discovery of disease biomarkers and druggable targets.Here we report t...Protein phosphorylation is one of the most important post-translational modifications.It is an active research area to study phosphoproteomics for discovery of disease biomarkers and druggable targets.Here we report the development of superparamagnetic Fe_(3)O_(4)@mZrO_(2) core-shell microspheres with mesoporous structures for highly efficient enrichment of phosphopeptides.We have demonstrated that the mesoporous ZrO_(2) layer dramatically improves the selective enrichment of phosphopeptides.Our approach allows for in-situ elution and sensitive identification of both mono-phosphorylated and multiphosphorylated peptides in MALDI-TOF mass spectrometry,with the detection limit of down to the femtomole range.The target phosphopeptides can reliably be enriched for MS analysis from various complex samples including the spiked protein digests and tumor cell lysates.The Fe_(3)O_(4)@mZrO_(2) coreshell microspheres promise a useful tool for phosphoproteomics by allowing for highly efficient and selective enrichment of the crucial signaling regulators in a low abundance.展开更多
基金We acknowledge the funding support from the National Natural Science Foundation of China(Grant Nos.52009016 and 52179118)the Fundamental Research Funds for the Central Universities(Grant No.2022QN1032).
文摘The effect of intermediate stress(in situ tunnel axial)on a strainburst is studied with a threedimensional(3D)bonded block distinct element method(DEM).A series of simulations of strainbursts under true triaxial in situ stress conditions(i.e.high tangential stress,moderate intermediate stress and low radial stress)of near-boundary rock masses are performed.Compared with the experimental results,the DEM model is able to capture the stress-strain response,failure pattern and energy balance of strainbursts.The fracturing processes of strainbursts are also numerically reproduced.Numerical results show that,as the intermediate stress increases:(1)The peak strain of strainbursts increases,the yield stress increases,the rock strength increases linearly,and the ratio of yield stress to rock strength decreases,indicating that the precursory information on strainbursts is enhanced;(2)Tensile and shear cracks increase significantly,and slabbing and bending of rock plates are more pronounced;and(3)The stored elastic strain energy and dissipated energy increase linearly,whereas the kinetic energy of the ejected rock fragments increases approximately exponentially,implying an increase in strainburst intensity.By comparing the experimental and numerical results,the effect of intermediate stress on the rock strength of strainbursts is discussed in order to address three key issues.Then,the Mogi criterion is applied to construct new strength criteria for strainbursts by converting the one-face free true triaxial stress state of a strainburst to its equivalent true triaxial stress state.In summary,the effect of intermediate stress on strainbursts is a double-edged sword that can enhance the rock strength and the precursory information of a strainburst,but also increase its intensity.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:2022QN1032。
文摘Strainbursts induced by cyclic disturbance with low frequency(termed as cyclicinduced strainbursts)are major dynamic disasters during deep excavation and mining.There is currently no quantitative criterion available for the prediction of such disastrous events.In this study,based on true triaxial experiments,we analyzed the deformation characteristics,established two novel strain criteria for the cyclic-induced strainbursts,and explained the physical meaning of these criteria.Characteristic strains for the cyclic-induced strainbursts were defined,including the control strain ε_(ctr),the strain caused by the combined dynamic and static loading ε_(sd),and the ultimate strain ε_(u) after strainbursts.As indicated by the results,the deformation evolution of the cyclic-induced strainbursts shows remarkable fatigue characteristics,which resemble that of rock subjected to cyclic loading and unloading.In other words,there are three stages during deformation evolution,namely,initial rapid growth,uniform velocity growth after several periods of disturbance,and sudden sharp growth preceding the burst.The ultimate strain ε_(u) is insensitive to the tangential static stress and disturbance amplitude,but it changes nonlinearly with disturbance frequency.From the perspective of deformation,the occurrence of a cyclic-induced strainburst is controlled by the control strainε_(ctr).Thus,a control strain criterion is proposed;that is,when the stain ε_(sd) is larger than the control strain ε_(ctr),a strainburst will be induced by cyclic disturbance.Moreover,based on the statistical results,a strain ratio criterion is proposed;that is,when the strain ratio ε_(sd)/ε_(u) is greater than 30%,a cyclic-induced strainburst will be induced.
基金supported in part by the National Natural Science Foundation of China (61421004,61402316,61333015,61632003)Doctoral Research Fund of Taiyuan University of Science and Technology under grant (20162009)National Key Technologies R&D Program(2016YFB0502002)
文摘An effective approach is proposed for 3D urban scene reconstruction in the form of point cloud with semantic labeling. Starting from high resolution oblique aerial images,our approach proceeds through three main stages: geographic reconstruction, geometrical reconstruction and semantic reconstruction. The absolute position and orientation of all the cameras relative to the real world are recovered in the geographic reconstruction stage. Then, in the geometrical reconstruction stage,an improved multi-view stereo matching method is employed to produce 3D dense points with color and normal information by taking into account the prior knowledge of aerial imagery.Finally the point cloud is classified into three classes(building,vegetation, and ground) by a rule-based hierarchical approach in the semantic reconstruction step. Experiments on complex urban scene show that our proposed 3-stage approach could generate reasonable reconstruction result robustly and efficiently.By comparing our final semantic reconstruction result with the manually labeled ground truth, classification accuracies from86.75% to 93.02% are obtained.
基金This work was supported by the National Science and Technology Major Project of China(Grant No.2016ZX05028–004)the Fundamental Research Funds for the Central Universities(Grant No.FRF-IC-18–007).
文摘A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.
基金Financial support for this research was provided by the Program for New Century Excellent Talents in the Ministry of Education in China(NCET-09-0446),NSFC(31370396,30800865) and lzujbky-2012-k22 to YuXia Wu
文摘Populus euphratica and Populuspruinosa, sister species in the Turanga Section (Salicaceae), growing in semi-arid saline areas are known for their high salinity tolerance. In this study, by combining growth level with Na+ and K+ contents, the expression level of vacuolar Na+/H+ antiporters was investigated for NaCl-induced changes in P. euphratica and t3. pru- inosa calli. Compared to R euphratica, P. pruinosa calli grew well in 200 mM NaC1 stress from 14. to 21 days. Increasing the stressed time caused an increase in Na+ content concomitant with a decrease in K+ content in P. euphratica calli, whereas, with the presence of 200 mM NaCI, K+ content has a less increase in 14 and 21 days than in 7 days which was detected in R pruinosa calli. The transcript levels of six genes coding for NHX-type Na+/H+ antiporters suggest that vacuolar NHX1-NHX6 antiporters play important roles in responding to salt stress in R pruinosa. Our data suggest that there exists a higher salt tolerance for P. pruinosa than P. euphratica at the cellular level, Na+ avoidance or accumulation is observed in cellular compartments, and that expression of NHX antiporters is linked to the accumulator phenotype.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:2022QN1032。
文摘This paper introduces the establishment of deep underground infrastructure for science and engineering research.First,the representative deep underground research laboratories and facilities in the world and their functions were summarized and reviewed.Then,the plan and service target of China Yulong Lake Laboratory were proposed for the storage of resources and energy,as well as the sealing of hazardous waste in deep underground space.On this basis,this paper reveals how the facility addresses its key scientific issue on“The law of fluid matter migration in deep underground space”and engineering significance.Finally,the construction progress of the facility components was demonstrated in details.As is hoped,this paper would provide useful reference to the deep underground research community;meanwhile,international collaboration on deep underground research is highly welcome.
基金supported by the National Natural Science Foundation of China(32230002)the National Key R&D Program of China(2020YFA0907200),and the Ba-Gui Scholar Program of Guangxi(To Z.G.H).
文摘Insertion sequences(ISs)exist widely in bacterial genomes,but their roles in the evolution of bacterial antiphage defense remain to be clarified.Here,we report that,under the pressure of phage infection,the IS1o96 transposition of Mycobacterium smegmatis into the Isr2 gene can occur at high frequencies,which endows the mutant mycobacterium with a broad-spectrum antiphage ability.Lsr2 functions as a negative regulator and directly silences expression of a gene island composed of 11 lipid metabolism-related genes.The complete or partial loss of the gene island leads to a significant decrease of bacteriophage adsorption to the mycobacterium,thus defending against phage infection.Strikingly,a phage that has evolved mutations in two tail-filament genes can re-escape from the Isr2 inactivation-triggered host defense.This study uncovered a new signaling pathway for activating antimycobacteriophage immunity by Is transposition and provided insight into the natural evolution of bacterial antiphage defense.
基金supported by the National Department Public Benefit Research Foundation(No. nyhyzx07-047)the Research Project of Zhejiang Education Department(No. Y200909301)and the Open Fund of Zhejiang Key Laboratory of Exploitation and Preservation of Costal Bioresources(No. J2010002)
文摘Computer assisted movement tracking was used to characterize the motility of two marine microalgae, lsochrysis galbana and Tetraselmis chui, and to investigate the toxicity of Cu, Pb, and Cd on motile percentage, curvilinear velocity, average path velocity, straight line velocity, linearity, straightness, and wobble. Except for motile percentage, all other motility parameters differed significantly between L galbana and T. chui. Based on relative motile percentage data, the median effective concentration (ECs0) of Cu on the motility of L galbana and T. chui was 31.4 and 1.3 gmol/L, respectively, while for Pb it was 37.8 and 10.9 ~tmol/L and for Cd it was 12 1.6 and 37.8 ~tmol/L, respectively. Compared to L galbana, T. chui was more sensitive to all tested metals. The toxic effect of the heavy metals on motility exhibited the following decreasing order for both species: Cu 〉 Pb 〉 Cd. Our results indicate that L galbana and T. chui motility is sensitive to heavy metals and can be used as an indicator for toxicology bioassays.
基金supported by the National Key Research and Development Program of China(2017YFE0131700)and the National Natural Science Foundation of China(21874096)+3 种基金a project supported by Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 ProjectJoint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Protein phosphorylation is one of the most important post-translational modifications.It is an active research area to study phosphoproteomics for discovery of disease biomarkers and druggable targets.Here we report the development of superparamagnetic Fe_(3)O_(4)@mZrO_(2) core-shell microspheres with mesoporous structures for highly efficient enrichment of phosphopeptides.We have demonstrated that the mesoporous ZrO_(2) layer dramatically improves the selective enrichment of phosphopeptides.Our approach allows for in-situ elution and sensitive identification of both mono-phosphorylated and multiphosphorylated peptides in MALDI-TOF mass spectrometry,with the detection limit of down to the femtomole range.The target phosphopeptides can reliably be enriched for MS analysis from various complex samples including the spiked protein digests and tumor cell lysates.The Fe_(3)O_(4)@mZrO_(2) coreshell microspheres promise a useful tool for phosphoproteomics by allowing for highly efficient and selective enrichment of the crucial signaling regulators in a low abundance.