A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,in...A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ.展开更多
This study endeavors to formulate a comprehensive methodology for establishing a Geological Knowledge Base(GKB)tailored to fracture-cavity reservoir outcrops within the North Tarim Basin.The acquisition of quantitativ...This study endeavors to formulate a comprehensive methodology for establishing a Geological Knowledge Base(GKB)tailored to fracture-cavity reservoir outcrops within the North Tarim Basin.The acquisition of quantitative geological parameters was accomplished through diverse means such as outcrop observations,thin section studies,unmanned aerial vehicle scanning,and high-resolution cameras.Subsequently,a three-dimensional digital outcrop model was generated,and the parameters were standardized.An assessment of traditional geological knowledge was conducted to delineate the knowledge framework,content,and system of the GKB.The basic parameter knowledge was extracted using multiscale fine characterization techniques,including core statistics,field observations,and microscopic thin section analysis.Key mechanism knowledge was identified by integrating trace elements from filling,isotope geochemical tests,and water-rock simulation experiments.Significant representational knowledge was then extracted by employing various methods such as multiple linear regression,neural network technology,and discriminant classification.Subsequently,an analogy study was performed on the karst fracture-cavity system(KFCS)in both outcrop and underground reservoir settings.The results underscored several key findings:(1)Utilization of a diverse range of techniques,including outcrop observations,core statistics,unmanned aerial vehicle scanning,high-resolution cameras,thin section analysis,and electron scanning imaging,enabled the acquisition and standardization of data.This facilitated effective management and integration of geological parameter data from multiple sources and scales.(2)The GKB for fracture-cavity reservoir outcrops,encompassing basic parameter knowledge,key mechanism knowledge,and significant representational knowledge,provides robust data support and systematic geological insights for the intricate and in-depth examination of the genetic mechanisms of fracture-cavity reservoirs.(3)The developmental characteristics of fracturecavities in karst outcrops offer effective,efficient,and accurate guidance for fracture-cavity research in underground karst reservoirs.The outlined construction method of the outcrop geological knowledge base is applicable to various fracture-cavity reservoirs in different layers and regions worldwide.展开更多
Patients with age-related hearing loss face hearing difficulties in daily life.The causes of age-related hearing loss are complex and include changes in peripheral hearing,central processing,and cognitive-related abil...Patients with age-related hearing loss face hearing difficulties in daily life.The causes of age-related hearing loss are complex and include changes in peripheral hearing,central processing,and cognitive-related abilities.Furthermore,the factors by which aging relates to hearing loss via changes in audito ry processing ability are still unclear.In this cross-sectional study,we evaluated 27 older adults(over 60 years old) with age-related hearing loss,21 older adults(over 60years old) with normal hearing,and 30 younger subjects(18-30 years old) with normal hearing.We used the outcome of the uppe r-threshold test,including the time-compressed thres h old and the speech recognition threshold in noisy conditions,as a behavioral indicator of auditory processing ability.We also used electroencephalogra p hy to identify presbycusis-related abnormalities in the brain while the participants were in a spontaneous resting state.The timecompressed threshold and speech recognition threshold data indicated significant diffe rences among the groups.In patients with age-related hearing loss,information masking(babble noise) had a greater effect than energy masking(speech-shaped noise) on processing difficulties.In terms of resting-state electroencephalography signals,we observed enhanced fro ntal lobe(Brodmann’s area,BA11) activation in the older adults with normal hearing compared with the younger participants with normal hearing,and greater activation in the parietal(BA7) and occipital(BA19) lobes in the individuals with age-related hearing loss compared with the younger adults.Our functional connection analysis suggested that compared with younger people,the older adults with normal hearing exhibited enhanced connections among networks,including the default mode network,sensorimotor network,cingulo-opercular network,occipital network,and frontoparietal network.These results suggest that both normal aging and the development of age-related hearing loss have a negative effect on advanced audito ry processing capabilities and that hearing loss accele rates the decline in speech comprehension,especially in speech competition situations.Older adults with normal hearing may have increased compensatory attentional resource recruitment represented by the to p-down active listening mechanism,while those with age-related hearing loss exhibit decompensation of network connections involving multisensory integration.展开更多
Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to sol...Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.展开更多
BACKGROUND Atherosclerosis is one of the main causes of coronary artery ostial lesions seen clinically.Secondary coronary artery ostial lesions are rare,and cases reported previously were associated with syphilitic va...BACKGROUND Atherosclerosis is one of the main causes of coronary artery ostial lesions seen clinically.Secondary coronary artery ostial lesions are rare,and cases reported previously were associated with syphilitic vasculitis and aortic dissection.Here,we report three rare cases of secondary coronary ostial lesions.Due to their rareness,these lesions can easily be neglected,which may lead to misdiagnosis and missed diagnosis.CASE SUMMARY We present three patients with acute myocardial infarction and unstable angina caused by secondary coronary artery ostial lesions.In Case 1,coronary angiography(CAG)revealed 90%stenosis of the left main coronary ostium.Chest contrast computed tomography(CT)suggested thymic carcinoma invading the left main coronary ostium.Coronary artery bypass grafting and tumor resection were performed.In Case 2,echocardiography revealed a sinus of Valsalva aneurysm(SVA)-like dilatation.CAG showed a right coronary sinus giant aneurysm and complete obstruction of the right coronary artery(RCA)ostium.Aortic contrast CT confirmed these findings.The Bentall procedure was performed.In Case 3,CT CAG identified an anomalous origin of the right coronary artery(AORCA)from the left sinus of Valsalva coursing between the aorta and pulmonary trunk,causing severe RCA ostium stenosis by compression.Surgical correction of the AORCA was performed.CONCLUSION The cases reported here suggest that we should consider other causes of coronary ostial lesions other than atherosclerosis.展开更多
Melt spinning （MS） and ball milling （BM） were employed to fabricate YMg11Ni alloy, and their structures and hydrogen storage performances were examined. The results reveal that the as-spun and as-milled alloys bot...Melt spinning （MS） and ball milling （BM） were employed to fabricate YMg11Ni alloy, and their structures and hydrogen storage performances were examined. The results reveal that the as-spun and as-milled alloys both exhibit the nanocrystalline and amorphous structure. The as-milled alloy shows a larger hydrogen absorption capacity as compared with the as-spun alloy. More than that, the as-milled alloy exhibits lower onset hydrogen desorption temperature than the as-spun one, which are 549.8 and 560.9 K, respectively. Additionally, the as-milled alloy shows a superior hydrogen desorption property to the as-spun one. On the basis of the time needed by desorbing hydrogen of 3 wt% H2, for the as- milled alloy, it needs 1106, 456, 343, and 180 s corresponding to hydrogen desorption temperatures of 593, 613, 633, and 653 K. However, for the as-spun alloy, the time needed is greater than 2928, 842, 356, and 197 s corresponding to the same temperatures. Hydrogen desorption activation energies of as-milled and as-spun alloys are 98.01 and 105.49 kJ/mol, respectively, which is responsible for that the as-milled alloy possesses a much faster dehydriding rate. By means of the measurement of pressure-composition-temperature （P-C-T） curves, the dehydrogenation enthalpy change of the alloys prepared by MS （△Hoe（MS）） and BM （△Hdc（BM）） is 81.84 and 79.46 kJ/mol, respectively, viz. △Hde（MS） 〉 △Hoc（BM）.展开更多
To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase st...To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase structures and morphology of the experimental alloys were in vestigated by X-ray diffraction and transmission electron microscopy. The results show that increasing milling time and Ni content accelerate the formation of nanocrystalline and amorphous structure. The gaseous hydrogen storage properties of the experimental alloys were determined by differential scanning calorimetry （DSC） and Sievert apparatus. In addition, increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy, respectively. The enthalpy change （ △H ）, entropy change （△S） and the dehydrogenation activation energy （Exde） markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.展开更多
LaMg11Ni+x wt.%Ni(x=100,200)alloys were prepared by ball milling and researched by various methods to study their structure and electrochemical hydrogen storage property.The outcomes reveal that increasing Ni content ...LaMg11Ni+x wt.%Ni(x=100,200)alloys were prepared by ball milling and researched by various methods to study their structure and electrochemical hydrogen storage property.The outcomes reveal that increasing Ni content contributes to improving its electrochemical performance.Particularly,the discharge capacity of as-milled(40 h)alloy will be increased from 157.3 to 1053.5 mAh/g through enhancing Ni percentage from 100 to 200 wt.%when discharging at 60 mAh/g.Ball milling obviously affects the electrochemical performanee of alloys.With milling duration prolonging,the discharge capacity of x=100 alloy keeps increasing,while that of the x=200 alloy has a maximum value.Milling time also affects the cycle stability of experimental alloys.Extendi ng milli ng duration clearly decreases the cycle stability of x=100 alloy but weakens that of the x=200 alloy at first and strengthens it later.In addition,prolonging milling time makes the milling prepared x=100 and 200 alloys get the maximal values of high rate discharge ability of 81.60%and 84.52%,respectively.展开更多
To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences...To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences of millingduration and Ni content on the electrochemical and gascous dynamics of the samples were studied in detail.Dehydrogena-tion activation cnergies of samples were calculated by using Kissinger and Arrhenius methods.The conclusions show thatthe dynamic properties of samples are significantly enhanced with the increase in Ni content.With the change of the miling duration,the gaseous hydrogenation rate and high rate discharging capability reach the maximal values.However,thedehydrogenation dynamics of sample alloys are always enhanced with the prolonging of milling duration.More concretely,prolonging milling duration from 5 to 60 h improves the dehydrogenation ratio of NdMgNi+100 wt.%Ni alloy from58.03%to 64.81%and that of NdMgNi+200 wt.%Ni alloy from 62.20%to 71.59%.Besides,the enhancement of gaseoushydrogen storage dynamics of the samples is believed to be the result of the declined dehydrogenation activation energyresulted from the increase in milling duration and Ni content.展开更多
基金This research was supported by the Major Scientific and Technological Projects of CNPC under grant ZD2019-183-006the National Natural Science Foundation of China(42072234).The authors would like to appreciate all the people,who supported the data,testing,and analyses.Many thanks to the anonymous reviewers,whose comments improve the quality of our manuscript.
文摘A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ.
基金supported by the Major Scientific and Technological Projects of CNPC under grant ZD2019-183-006the National Science and Technology Major Project of China (2016ZX05014002-006)the National Natural Science Foundation of China (42072234,42272180)。
文摘This study endeavors to formulate a comprehensive methodology for establishing a Geological Knowledge Base(GKB)tailored to fracture-cavity reservoir outcrops within the North Tarim Basin.The acquisition of quantitative geological parameters was accomplished through diverse means such as outcrop observations,thin section studies,unmanned aerial vehicle scanning,and high-resolution cameras.Subsequently,a three-dimensional digital outcrop model was generated,and the parameters were standardized.An assessment of traditional geological knowledge was conducted to delineate the knowledge framework,content,and system of the GKB.The basic parameter knowledge was extracted using multiscale fine characterization techniques,including core statistics,field observations,and microscopic thin section analysis.Key mechanism knowledge was identified by integrating trace elements from filling,isotope geochemical tests,and water-rock simulation experiments.Significant representational knowledge was then extracted by employing various methods such as multiple linear regression,neural network technology,and discriminant classification.Subsequently,an analogy study was performed on the karst fracture-cavity system(KFCS)in both outcrop and underground reservoir settings.The results underscored several key findings:(1)Utilization of a diverse range of techniques,including outcrop observations,core statistics,unmanned aerial vehicle scanning,high-resolution cameras,thin section analysis,and electron scanning imaging,enabled the acquisition and standardization of data.This facilitated effective management and integration of geological parameter data from multiple sources and scales.(2)The GKB for fracture-cavity reservoir outcrops,encompassing basic parameter knowledge,key mechanism knowledge,and significant representational knowledge,provides robust data support and systematic geological insights for the intricate and in-depth examination of the genetic mechanisms of fracture-cavity reservoirs.(3)The developmental characteristics of fracturecavities in karst outcrops offer effective,efficient,and accurate guidance for fracture-cavity research in underground karst reservoirs.The outlined construction method of the outcrop geological knowledge base is applicable to various fracture-cavity reservoirs in different layers and regions worldwide.
基金supported by the National Natural Science Foundation of China,Nos.82171138 (to YQZ),82071 062 (to YXC)the Natural Science Foundation of Guangdong Province,No.2021A1515012038 (to YXC)+1 种基金the Fundamental Research Funds for the Central Universities,No.20ykpy91 (to YXC)the Sun Yat-Sen Clinical Research Cultivating Program,No.SYS-Q-201903 (to YXC)。
文摘Patients with age-related hearing loss face hearing difficulties in daily life.The causes of age-related hearing loss are complex and include changes in peripheral hearing,central processing,and cognitive-related abilities.Furthermore,the factors by which aging relates to hearing loss via changes in audito ry processing ability are still unclear.In this cross-sectional study,we evaluated 27 older adults(over 60 years old) with age-related hearing loss,21 older adults(over 60years old) with normal hearing,and 30 younger subjects(18-30 years old) with normal hearing.We used the outcome of the uppe r-threshold test,including the time-compressed thres h old and the speech recognition threshold in noisy conditions,as a behavioral indicator of auditory processing ability.We also used electroencephalogra p hy to identify presbycusis-related abnormalities in the brain while the participants were in a spontaneous resting state.The timecompressed threshold and speech recognition threshold data indicated significant diffe rences among the groups.In patients with age-related hearing loss,information masking(babble noise) had a greater effect than energy masking(speech-shaped noise) on processing difficulties.In terms of resting-state electroencephalography signals,we observed enhanced fro ntal lobe(Brodmann’s area,BA11) activation in the older adults with normal hearing compared with the younger participants with normal hearing,and greater activation in the parietal(BA7) and occipital(BA19) lobes in the individuals with age-related hearing loss compared with the younger adults.Our functional connection analysis suggested that compared with younger people,the older adults with normal hearing exhibited enhanced connections among networks,including the default mode network,sensorimotor network,cingulo-opercular network,occipital network,and frontoparietal network.These results suggest that both normal aging and the development of age-related hearing loss have a negative effect on advanced audito ry processing capabilities and that hearing loss accele rates the decline in speech comprehension,especially in speech competition situations.Older adults with normal hearing may have increased compensatory attentional resource recruitment represented by the to p-down active listening mechanism,while those with age-related hearing loss exhibit decompensation of network connections involving multisensory integration.
基金the Natural Science Key Foundation of Heilongjiang Province of China (No. ZJG0503) China-UK Sci-ence Network from Royal Society UK
文摘Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.
文摘BACKGROUND Atherosclerosis is one of the main causes of coronary artery ostial lesions seen clinically.Secondary coronary artery ostial lesions are rare,and cases reported previously were associated with syphilitic vasculitis and aortic dissection.Here,we report three rare cases of secondary coronary ostial lesions.Due to their rareness,these lesions can easily be neglected,which may lead to misdiagnosis and missed diagnosis.CASE SUMMARY We present three patients with acute myocardial infarction and unstable angina caused by secondary coronary artery ostial lesions.In Case 1,coronary angiography(CAG)revealed 90%stenosis of the left main coronary ostium.Chest contrast computed tomography(CT)suggested thymic carcinoma invading the left main coronary ostium.Coronary artery bypass grafting and tumor resection were performed.In Case 2,echocardiography revealed a sinus of Valsalva aneurysm(SVA)-like dilatation.CAG showed a right coronary sinus giant aneurysm and complete obstruction of the right coronary artery(RCA)ostium.Aortic contrast CT confirmed these findings.The Bentall procedure was performed.In Case 3,CT CAG identified an anomalous origin of the right coronary artery(AORCA)from the left sinus of Valsalva coursing between the aorta and pulmonary trunk,causing severe RCA ostium stenosis by compression.Surgical correction of the AORCA was performed.CONCLUSION The cases reported here suggest that we should consider other causes of coronary ostial lesions other than atherosclerosis.
基金financially supported by the National Natural Science Foundations of China(Nos.51371094 and 51471054)the Natural Science Foundation of Inner Mongolia,China(No.2015MS0558)
文摘Melt spinning （MS） and ball milling （BM） were employed to fabricate YMg11Ni alloy, and their structures and hydrogen storage performances were examined. The results reveal that the as-spun and as-milled alloys both exhibit the nanocrystalline and amorphous structure. The as-milled alloy shows a larger hydrogen absorption capacity as compared with the as-spun alloy. More than that, the as-milled alloy exhibits lower onset hydrogen desorption temperature than the as-spun one, which are 549.8 and 560.9 K, respectively. Additionally, the as-milled alloy shows a superior hydrogen desorption property to the as-spun one. On the basis of the time needed by desorbing hydrogen of 3 wt% H2, for the as- milled alloy, it needs 1106, 456, 343, and 180 s corresponding to hydrogen desorption temperatures of 593, 613, 633, and 653 K. However, for the as-spun alloy, the time needed is greater than 2928, 842, 356, and 197 s corresponding to the same temperatures. Hydrogen desorption activation energies of as-milled and as-spun alloys are 98.01 and 105.49 kJ/mol, respectively, which is responsible for that the as-milled alloy possesses a much faster dehydriding rate. By means of the measurement of pressure-composition-temperature （P-C-T） curves, the dehydrogenation enthalpy change of the alloys prepared by MS （△Hoe（MS）） and BM （△Hdc（BM）） is 81.84 and 79.46 kJ/mol, respectively, viz. △Hde（MS） 〉 △Hoc（BM）.
基金financially sponsored by National Natural Science Foundation of China (51471054)
文摘To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase structures and morphology of the experimental alloys were in vestigated by X-ray diffraction and transmission electron microscopy. The results show that increasing milling time and Ni content accelerate the formation of nanocrystalline and amorphous structure. The gaseous hydrogen storage properties of the experimental alloys were determined by differential scanning calorimetry （DSC） and Sievert apparatus. In addition, increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy, respectively. The enthalpy change （ △H ）, entropy change （△S） and the dehydrogenation activation energy （Exde） markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.
基金the National Natural Science Foundations of China(51161015 and 51371094).
文摘LaMg11Ni+x wt.%Ni(x=100,200)alloys were prepared by ball milling and researched by various methods to study their structure and electrochemical hydrogen storage property.The outcomes reveal that increasing Ni content contributes to improving its electrochemical performance.Particularly,the discharge capacity of as-milled(40 h)alloy will be increased from 157.3 to 1053.5 mAh/g through enhancing Ni percentage from 100 to 200 wt.%when discharging at 60 mAh/g.Ball milling obviously affects the electrochemical performanee of alloys.With milling duration prolonging,the discharge capacity of x=100 alloy keeps increasing,while that of the x=200 alloy has a maximum value.Milling time also affects the cycle stability of experimental alloys.Extendi ng milli ng duration clearly decreases the cycle stability of x=100 alloy but weakens that of the x=200 alloy at first and strengthens it later.In addition,prolonging milling time makes the milling prepared x=100 and 200 alloys get the maximal values of high rate discharge ability of 81.60%and 84.52%,respectively.
基金It is sincere thanks to the National Natural Science Foundation of China(Nos.51871125 and 51761032)the MajorScience and Technology Innovation Projects in Shandong Province(2019JZZYO10320)for the financial support of this work.
文摘To improve the hydrogenation and dehydrogenation dynamics of NdMg12-type alloy,we replaced part of Mg with Ni in thesamples and used the ball milling method to prepare NdMg11Ni+x wt.%Ni(x=100,200)samples.The infuences of millingduration and Ni content on the electrochemical and gascous dynamics of the samples were studied in detail.Dehydrogena-tion activation cnergies of samples were calculated by using Kissinger and Arrhenius methods.The conclusions show thatthe dynamic properties of samples are significantly enhanced with the increase in Ni content.With the change of the miling duration,the gaseous hydrogenation rate and high rate discharging capability reach the maximal values.However,thedehydrogenation dynamics of sample alloys are always enhanced with the prolonging of milling duration.More concretely,prolonging milling duration from 5 to 60 h improves the dehydrogenation ratio of NdMgNi+100 wt.%Ni alloy from58.03%to 64.81%and that of NdMgNi+200 wt.%Ni alloy from 62.20%to 71.59%.Besides,the enhancement of gaseoushydrogen storage dynamics of the samples is believed to be the result of the declined dehydrogenation activation energyresulted from the increase in milling duration and Ni content.
