Arson presents a challenging crime scene for fire investigators worldwide. Key to the investigation of suspected arson cases is the analysis of fire debris for the presence of accelerants or ignitable liquids. This st...Arson presents a challenging crime scene for fire investigators worldwide. Key to the investigation of suspected arson cases is the analysis of fire debris for the presence of accelerants or ignitable liquids. This study has investigated the application and method development of vapor phase mid-Infrared (mid-IR) spectroscopy using a field portable quantum cascade laser (QCL) based system for the detection and identification of accelerant residues such as gasoline, diesel, and ethanol in fire debris. A searchable spectral library of various ignitable fluids and fuel components measured in the vapor phase was constructed that allowed for real-time identification of accelerants present in samples using software developed in-house. Measurement of vapors collected from paper material that had been doused with an accelerant followed by controlled burning and then extinguished with water showed that positive identification could be achieved for gasoline, diesel, and ethanol. This vapor phase mid-IR QCL method is rapid, easy to use, and has the sensitivity and discrimination capability that make it well suited for non-destructive crime scene sample analysis. Sampling and measurement can be performed in minutes with this 7.5 kg instrument. This vibrational spectroscopic method required no time-consuming sample pretreatment or complicated solvent extraction procedure. The results of this initial feasibility study demonstrate that this portable fire debris analyzer would greatly benefit arson investigators performing analysis on-site.展开更多
Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a ...Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a self-supporting copper-silver(CuAg)catalyst.The gust of Ag atoms with larger atomic sizes caused a tensile strain in the Cu matrix.Meanwhile,the chemical-potential difference induced electron transfer from Cu to Ag,and the two factors jointly led to the upshift of Cu d-band and improved the catalytic activity.Consequently,the CuAg electrode exhibited a high turnover frequency(12 times that of pure Cu),a low overpotential at high current density(superior to platinum foil),and high durability(1.57%decay over 180 h).Our work demonstrates that FSP is a powerful method for preparing self-supporting catalysts of immiscible alloys with high catalytic performance.展开更多
Humins are common undesirable sideproducts during many acid-catalyzed reactions in renewable biomass platform conversion. However, few studies have been reported to the efficient utilization of humins.For the first ti...Humins are common undesirable sideproducts during many acid-catalyzed reactions in renewable biomass platform conversion. However, few studies have been reported to the efficient utilization of humins.For the first time, the selective catalytic conversion of biomass-derived humins into cyclic hydrocarbons with high conversion rate and selectivity is presented using a home-made Ru/W-P-Si-O bifunctional catalyst. The multistage polymerization structure of humins was studied through controlled experiments.Results show that the CAC bond network can be efficiently depolymerized at a mild reaction temperature of 340–380 °C, catalyzed by the cooperative catalysis of nano-Ru particles and porous strong Lewis solid acid. Particularly, 95.4% conversion of humins was achieved under the optimal condition with up to 88.3%yield of cyclic hydrocarbons. The detailed composition after liquefaction was also analyzed. This study paves the way for the efficient production of cyclic and aromatic hydrocarbons from furan-derived humin polymer through Lewis acid-catalyzed Diels–Alder reactions between furan rings.展开更多
Objective: To investigate the incidence of retinopathy of prematurity (ROP), analyze the risk factors of ROP, and put forward effective screening strategies, to reduce its incidence. Background: Retinopathy of prematu...Objective: To investigate the incidence of retinopathy of prematurity (ROP), analyze the risk factors of ROP, and put forward effective screening strategies, to reduce its incidence. Background: Retinopathy of prematurity (ROP) is an eye disease that can happen in new born premature (born early) babies or have weigh less than 3 pounds at birth. ROP happens when abnormal blood vessels grow in the retina. There are multiple risk factors, which are causing the ROP. In our study we will analyses the risk factors of ROP. Methods: From February 2016 to August 2021, 190 premature infants in the neonatal intensive care unit (NICU) who received inpatient care and ophthalmic screening was selected as study subjects. ROP group (n = 32) and non-ROP group (n = 158) were selected, and the clinical data of the two groups were compared. Including oxygen concentration, mechanical ventilation, broncho pulmonic dysplasia, delivery mode (cesarean section, vaginal delivery), blood transfusion, anemia, gestational diabetes, gestational hypertension, fetal distress, preterm birth weight, gestation age, etc. Women were divided into two groups according to whether they had gestational diabetes mellitus (GDM) or not: gestational diabetic (n = 38) and non-gestational diabetics (n = 152). Age, pregnancy times, birth times, oxygen inhalation, birth weight, and gestational age were compared between the two groups. The X<sup>2</sup> test for counting data and the t-test for measuring data are then conducted according to the distribution characteristics of the data, The correlation analysis between ROP and a single risk factor was performed by chi-square test, and the analysis of the correlation between many risk factors and ROP was conducted by Logistic regression analysis. Results: 1) The incidence of ROP in the GDM group was higher than that in the non-GDM group (P P > 0.05). 3) Univariate analysis showed that oxygen use, birth weight, gestational age, bronchopulmonary dysplasia, pregnancy-induced hypertension, and fetal distress in the ROP group and non-ROP group were statistically significant (P P > 0.05). 4) Logistic multivariate analysis showed that oxygen use, gestational hypertension, diabetes mellitus during pregnancy, fetal distress, bronchopulmonary dysplasia, birth weight, and gestational age were the main risk factors for ROP. Conclusion: 1) Gestational diabetes mellitus is a high-risk factor for ROP. 2) Oxygen inhalation, birth weight, and gestational age are related to the occurrence and development of ROP. 3) In determining the initial screening time for ROP.展开更多
Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet excit...Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet exciton transition processes.Five host molecules with different functional units were selected,thus providing dif-ferent intermolecular interactions in the host/guest systems.Therefore,the delayed emissions were regulated from 536 to 624 nm via the tuning of the triplet exciton transition processes of OTC in different hosts.Experimental data and theoretical calculations revealed that the varied triplet transition behaviors resulted from the competition between the intersystem crossing(ISC)process of OTC-monomer and the reverse intersystem crossing(RISC)process of OTC-aggregates.This work proves the superior structure of buckybowl-based luminophore for controlling triplet exciton transition processes and supplies a new perspective for persistent afterglow luminophore design.展开更多
Oil and gas currently still hold a leading role in the global energy mix.The recent drastic increase in unconventional oil and gas production contributes significantly to strike a balance between the global demand and...Oil and gas currently still hold a leading role in the global energy mix.The recent drastic increase in unconventional oil and gas production contributes significantly to strike a balance between the global demand and supply of oil and gas.However,a range of important fundamental questions about the unconventional oil and gas resources have not been adequately answered.Little is known about the distribution and accumulation patterns,as well as the exploration and development characteristics of unconventional oil and gas.The current status of global oil and gas exploration was reviewed and four key theoretical issues regarding the unconventional oil and gas geology were identified:(1)the traditional concept and definition of“petroleum system”needs to be revisited.The concept of a“holistic-process accumulation”model of a“total petroleum system”in petroliferous basins was proposed to analyze the unconventional hydrocarbon accumulation mechanisms from four key aspects of quantitative studies on hydrocarbon generation-expulsion-migration-accumulation processes.(2)The second issue is related to fine-grained sedimentary system and sedimentary facies of tight reservoirs.Through analyzing the relationship between fine-grained sediments and unconventional hydrocarbon accumulation,three research integration areas were put forward.(3)The third issue is on the micro-nano pore system and fluid phase behavior in shales and tight reservoirs.Five aspects of micro-nano pore system were identified to focus on unconventional hydrocarbon research,and the characteristics of micro-nano pore development and fluid phase behavior in micro-nanopores were elucidated.(4)The fourth issue is related to unconventional hydrocarbon accumulation patterns and resource evaluation.Based on the characteristics of unconventional hydrocarbon accumulation,an evaluation system for unconventional hydrocarbon resources was established and optimized.展开更多
Developing novel long-lived room-temperature polymer phosphorescence(RTPP)materials could significantly expand their application scope.Herein,a series of RTPP materials based on eight simple vanilla derivatives for se...Developing novel long-lived room-temperature polymer phosphorescence(RTPP)materials could significantly expand their application scope.Herein,a series of RTPP materials based on eight simple vanilla derivatives for security ink application are reported.Attributed to strong mutual hydrogen bonding with polyvinyl alcohol(PVA)matrix,vanilla-doped PVA films exhibit ultralong phosphorescence emission under ambient conditions observed by naked eyes,where methyl vanillate shows the longest emission time up to 7 s.Impressively,when vanilla-doped PVA materials are utilized as invisible security inks,and the inks not only present excellent luminescent emission stability under ambient conditions but also maintain perfect reversibility between room temperature and 65℃ for multiple cycles.Owing to the unique RTPP performance,an advanced anticounterfeiting data encoding/reading strategy based on handwriting technology and complex pattern steganography is developed.展开更多
Dispersed fringe sensors are a promising approach for sensing the large-scale physical step between adjacent segments with acceptable accuracy.However,the nature of dispersion in a dispersed fringe sensor leads to the...Dispersed fringe sensors are a promising approach for sensing the large-scale physical step between adjacent segments with acceptable accuracy.However,the nature of dispersion in a dispersed fringe sensor leads to the ideal dispersed fringe pattern becoming vulnerable to noise,particularly at low light levels.A reliable merit-functionbased algorithm with an active actuation is introduced here.The feasibility of our algorithm is numerically demonstrated,and Monte Carlo experiments for different signal-to-noise ratios are conducted to assess its robustness.The results show that the method is valid even when the signal-to-noise ratio is as low as 1.展开更多
Next basket prediction attempts to provide sequential recommendations to users based on a sequence of the user's previous purchases. Ideally, a good prediction model should be able to explore the personalized pref...Next basket prediction attempts to provide sequential recommendations to users based on a sequence of the user's previous purchases. Ideally, a good prediction model should be able to explore the personalized preference of the users, as well as the sequential relations of the items. This goal of modeling becomes even more challenging when both factors are time-dependent. However, existing methods either take these two aspects as static, or only consider temporal dynamics for one of the two aspects. In this work, we propose the dynamic representation learning approach for time-dependent next basket recommendation, which jointly models the dynamic nature of user preferences and item relations. To do so, we explicitly model the transaction timestamps, as well as the dynamic representations of both users and items, so as to capture the personalized user preference on each individual item dynamically. Experiments on three real-world retail datasets show that our method significantly outperforms several state-of-the-art methods for next basket recommendation.展开更多
Twin formation energy is an intrinsic quantity for bulk crystals.At the nanoscale,the twin formation energy of covalent SiC nanowires goes up with decreasing dimension.In contrast,this article reports that the twin fo...Twin formation energy is an intrinsic quantity for bulk crystals.At the nanoscale,the twin formation energy of covalent SiC nanowires goes up with decreasing dimension.In contrast,this article reports that the twin formation energy of metallic nanowires goes down with decreasing dimension.This result is based on classical molecular statics simulations of four representative metals.Cu and Al represent face-centered cubic(FCC)metals of low and high twin formation energies.Ta represents a body-centered cubic(BCC)metal,and Mg represents a hexagonal close-packed(HCP)metal.For all the four metals,the dependence of twin formation energy on size correlates with lower twin formation energy near surfaces,according to atomic-level analysis.Based on this atomic-level insight,the authors propose a core–shell model that reveals the twin formation energy as inversely proportional to the diameter of nanowires.This dependence is in agreement with the results of molecular statics simulations.展开更多
文摘Arson presents a challenging crime scene for fire investigators worldwide. Key to the investigation of suspected arson cases is the analysis of fire debris for the presence of accelerants or ignitable liquids. This study has investigated the application and method development of vapor phase mid-Infrared (mid-IR) spectroscopy using a field portable quantum cascade laser (QCL) based system for the detection and identification of accelerant residues such as gasoline, diesel, and ethanol in fire debris. A searchable spectral library of various ignitable fluids and fuel components measured in the vapor phase was constructed that allowed for real-time identification of accelerants present in samples using software developed in-house. Measurement of vapors collected from paper material that had been doused with an accelerant followed by controlled burning and then extinguished with water showed that positive identification could be achieved for gasoline, diesel, and ethanol. This vapor phase mid-IR QCL method is rapid, easy to use, and has the sensitivity and discrimination capability that make it well suited for non-destructive crime scene sample analysis. Sampling and measurement can be performed in minutes with this 7.5 kg instrument. This vibrational spectroscopic method required no time-consuming sample pretreatment or complicated solvent extraction procedure. The results of this initial feasibility study demonstrate that this portable fire debris analyzer would greatly benefit arson investigators performing analysis on-site.
基金supported by the National Natural Science Foundation of China (Nos.51871160 and 52101266)the Natural Science Foundation of Hefei Grant (No.2022046)。
文摘Commercial hydrogen production involves the development of efficient hydrogen evolution reaction catalysts.Herein,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a self-supporting copper-silver(CuAg)catalyst.The gust of Ag atoms with larger atomic sizes caused a tensile strain in the Cu matrix.Meanwhile,the chemical-potential difference induced electron transfer from Cu to Ag,and the two factors jointly led to the upshift of Cu d-band and improved the catalytic activity.Consequently,the CuAg electrode exhibited a high turnover frequency(12 times that of pure Cu),a low overpotential at high current density(superior to platinum foil),and high durability(1.57%decay over 180 h).Our work demonstrates that FSP is a powerful method for preparing self-supporting catalysts of immiscible alloys with high catalytic performance.
基金supported financially by the National Natural Science Foundation of China (No. 21972056)Natural Science Foundation of Inner Mongolia, China (Nos. 2018LH02009 and 2019BS02012)+1 种基金Science Foundation of High Education Institutes of Inner Mongolia, China (No. NJZY20071)Science Foundation Inner Mongolia University of Technology (No. ZZ201804)。
文摘Humins are common undesirable sideproducts during many acid-catalyzed reactions in renewable biomass platform conversion. However, few studies have been reported to the efficient utilization of humins.For the first time, the selective catalytic conversion of biomass-derived humins into cyclic hydrocarbons with high conversion rate and selectivity is presented using a home-made Ru/W-P-Si-O bifunctional catalyst. The multistage polymerization structure of humins was studied through controlled experiments.Results show that the CAC bond network can be efficiently depolymerized at a mild reaction temperature of 340–380 °C, catalyzed by the cooperative catalysis of nano-Ru particles and porous strong Lewis solid acid. Particularly, 95.4% conversion of humins was achieved under the optimal condition with up to 88.3%yield of cyclic hydrocarbons. The detailed composition after liquefaction was also analyzed. This study paves the way for the efficient production of cyclic and aromatic hydrocarbons from furan-derived humin polymer through Lewis acid-catalyzed Diels–Alder reactions between furan rings.
文摘Objective: To investigate the incidence of retinopathy of prematurity (ROP), analyze the risk factors of ROP, and put forward effective screening strategies, to reduce its incidence. Background: Retinopathy of prematurity (ROP) is an eye disease that can happen in new born premature (born early) babies or have weigh less than 3 pounds at birth. ROP happens when abnormal blood vessels grow in the retina. There are multiple risk factors, which are causing the ROP. In our study we will analyses the risk factors of ROP. Methods: From February 2016 to August 2021, 190 premature infants in the neonatal intensive care unit (NICU) who received inpatient care and ophthalmic screening was selected as study subjects. ROP group (n = 32) and non-ROP group (n = 158) were selected, and the clinical data of the two groups were compared. Including oxygen concentration, mechanical ventilation, broncho pulmonic dysplasia, delivery mode (cesarean section, vaginal delivery), blood transfusion, anemia, gestational diabetes, gestational hypertension, fetal distress, preterm birth weight, gestation age, etc. Women were divided into two groups according to whether they had gestational diabetes mellitus (GDM) or not: gestational diabetic (n = 38) and non-gestational diabetics (n = 152). Age, pregnancy times, birth times, oxygen inhalation, birth weight, and gestational age were compared between the two groups. The X<sup>2</sup> test for counting data and the t-test for measuring data are then conducted according to the distribution characteristics of the data, The correlation analysis between ROP and a single risk factor was performed by chi-square test, and the analysis of the correlation between many risk factors and ROP was conducted by Logistic regression analysis. Results: 1) The incidence of ROP in the GDM group was higher than that in the non-GDM group (P P > 0.05). 3) Univariate analysis showed that oxygen use, birth weight, gestational age, bronchopulmonary dysplasia, pregnancy-induced hypertension, and fetal distress in the ROP group and non-ROP group were statistically significant (P P > 0.05). 4) Logistic multivariate analysis showed that oxygen use, gestational hypertension, diabetes mellitus during pregnancy, fetal distress, bronchopulmonary dysplasia, birth weight, and gestational age were the main risk factors for ROP. Conclusion: 1) Gestational diabetes mellitus is a high-risk factor for ROP. 2) Oxygen inhalation, birth weight, and gestational age are related to the occurrence and development of ROP. 3) In determining the initial screening time for ROP.
基金National Natural Scientific Foundation of China,Grant/Award Numbers:21975021,21975020,21875019,21871119,22105019,22175023Beijing National Laboratory for Molecular Sciences,Grant/Award Number:BNLMS192007BIT Research and Innovation Promoting Project,Grant/Award Number:2022YCXZ035。
文摘Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet exciton transition processes.Five host molecules with different functional units were selected,thus providing dif-ferent intermolecular interactions in the host/guest systems.Therefore,the delayed emissions were regulated from 536 to 624 nm via the tuning of the triplet exciton transition processes of OTC in different hosts.Experimental data and theoretical calculations revealed that the varied triplet transition behaviors resulted from the competition between the intersystem crossing(ISC)process of OTC-monomer and the reverse intersystem crossing(RISC)process of OTC-aggregates.This work proves the superior structure of buckybowl-based luminophore for controlling triplet exciton transition processes and supplies a new perspective for persistent afterglow luminophore design.
基金This study was financially supported by the Beijing Social Science Foundation （No. 17JDYJB010） and the Special Fund for Joint Development Program of Beijing Municipal Commission of Education.
基金This work was funded by National Science and Technology Major Project(2011ZX05043)CNPC Major Science and Technology Project(2013E0502)Innovation Project of PetroChina Research Institute of Exploration and Development(2012Y006).
文摘Oil and gas currently still hold a leading role in the global energy mix.The recent drastic increase in unconventional oil and gas production contributes significantly to strike a balance between the global demand and supply of oil and gas.However,a range of important fundamental questions about the unconventional oil and gas resources have not been adequately answered.Little is known about the distribution and accumulation patterns,as well as the exploration and development characteristics of unconventional oil and gas.The current status of global oil and gas exploration was reviewed and four key theoretical issues regarding the unconventional oil and gas geology were identified:(1)the traditional concept and definition of“petroleum system”needs to be revisited.The concept of a“holistic-process accumulation”model of a“total petroleum system”in petroliferous basins was proposed to analyze the unconventional hydrocarbon accumulation mechanisms from four key aspects of quantitative studies on hydrocarbon generation-expulsion-migration-accumulation processes.(2)The second issue is related to fine-grained sedimentary system and sedimentary facies of tight reservoirs.Through analyzing the relationship between fine-grained sediments and unconventional hydrocarbon accumulation,three research integration areas were put forward.(3)The third issue is on the micro-nano pore system and fluid phase behavior in shales and tight reservoirs.Five aspects of micro-nano pore system were identified to focus on unconventional hydrocarbon research,and the characteristics of micro-nano pore development and fluid phase behavior in micro-nanopores were elucidated.(4)The fourth issue is related to unconventional hydrocarbon accumulation patterns and resource evaluation.Based on the characteristics of unconventional hydrocarbon accumulation,an evaluation system for unconventional hydrocarbon resources was established and optimized.
基金supported by the National Natural Science Foundation of China(21875025)the Special Program of Chongqing Science and Technology Commission(cstc2018jcyjAX0296 and cstc2017zdcyzdyfX0007)+4 种基金Innovation Research Group at Institutions of Higher Education in Chongqing(CXQT19027)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-K201801101)the Postgraduate Tutor Team Project of Polymer Materials Engineering of Chongqing Education CommissionThe research was also supported by the Singapore Agency for Science,TechnologyResearch(A∗STAR)AME IRG grant(A1883c0005).
文摘Developing novel long-lived room-temperature polymer phosphorescence(RTPP)materials could significantly expand their application scope.Herein,a series of RTPP materials based on eight simple vanilla derivatives for security ink application are reported.Attributed to strong mutual hydrogen bonding with polyvinyl alcohol(PVA)matrix,vanilla-doped PVA films exhibit ultralong phosphorescence emission under ambient conditions observed by naked eyes,where methyl vanillate shows the longest emission time up to 7 s.Impressively,when vanilla-doped PVA materials are utilized as invisible security inks,and the inks not only present excellent luminescent emission stability under ambient conditions but also maintain perfect reversibility between room temperature and 65℃ for multiple cycles.Owing to the unique RTPP performance,an advanced anticounterfeiting data encoding/reading strategy based on handwriting technology and complex pattern steganography is developed.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11873008 and61008038)the Innovation Fund of Key Laboratory of Chinese Academy of Sciences(No.CXJJ-17S053)the National Key Research and Development Program of China(No.2016YFB0501100)
文摘Dispersed fringe sensors are a promising approach for sensing the large-scale physical step between adjacent segments with acceptable accuracy.However,the nature of dispersion in a dispersed fringe sensor leads to the ideal dispersed fringe pattern becoming vulnerable to noise,particularly at low light levels.A reliable merit-functionbased algorithm with an active actuation is introduced here.The feasibility of our algorithm is numerically demonstrated,and Monte Carlo experiments for different signal-to-noise ratios are conducted to assess its robustness.The results show that the method is valid even when the signal-to-noise ratio is as low as 1.
基金financially supported by the National Natural Science Foundation of China(21875025)the Special Program of Chongqing Science and Technology Commission(cstc2018jcyjAX0296)+3 种基金the Innovation Research Group at the Institutions of Higher Education in Chongqing(CXQT19027)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-K201801101)Chongqing Talent Program,the Science and Technology Project of Banan District,and the Innovation Support Plan for the Returned Overseas of Chongqing(cx2020052)supported by Singapore Academic Research Fund(RT12/19 and MOE-MOET2EP10120-0003)。
基金This research work was supported by the National Natural Science Foundation of China under Grant Nos.61802029,and 61602451the Fundamental Research for the Central Universities of China under Grant No.500419741.
文摘Next basket prediction attempts to provide sequential recommendations to users based on a sequence of the user's previous purchases. Ideally, a good prediction model should be able to explore the personalized preference of the users, as well as the sequential relations of the items. This goal of modeling becomes even more challenging when both factors are time-dependent. However, existing methods either take these two aspects as static, or only consider temporal dynamics for one of the two aspects. In this work, we propose the dynamic representation learning approach for time-dependent next basket recommendation, which jointly models the dynamic nature of user preferences and item relations. To do so, we explicitly model the transaction timestamps, as well as the dynamic representations of both users and items, so as to capture the personalized user preference on each individual item dynamically. Experiments on three real-world retail datasets show that our method significantly outperforms several state-of-the-art methods for next basket recommendation.
基金The authors acknowledge the financial support of Defense Threat Reduction Agency(HDTRA1-09-1-0027)H.H.also acknowledges the financial support of National Science Foundation(DMR0906349 and CMMI-0856426).
文摘Twin formation energy is an intrinsic quantity for bulk crystals.At the nanoscale,the twin formation energy of covalent SiC nanowires goes up with decreasing dimension.In contrast,this article reports that the twin formation energy of metallic nanowires goes down with decreasing dimension.This result is based on classical molecular statics simulations of four representative metals.Cu and Al represent face-centered cubic(FCC)metals of low and high twin formation energies.Ta represents a body-centered cubic(BCC)metal,and Mg represents a hexagonal close-packed(HCP)metal.For all the four metals,the dependence of twin formation energy on size correlates with lower twin formation energy near surfaces,according to atomic-level analysis.Based on this atomic-level insight,the authors propose a core–shell model that reveals the twin formation energy as inversely proportional to the diameter of nanowires.This dependence is in agreement with the results of molecular statics simulations.
