The orientations of ancient tombs have attracted increasing scholarly attention,as they offer valuable insights into early social structures,cultural traditions,and the relationship between humans and their environmen...The orientations of ancient tombs have attracted increasing scholarly attention,as they offer valuable insights into early social structures,cultural traditions,and the relationship between humans and their environment.However,the application of machine learning algorithms to the study of tomb orientation remains relatively underexplored.In this study,we employed a Gaussian mixture model to conduct a systematic analysis of the spatial and temporal evolution of Neolithic tomb orientations in Central China.We also examined the relationship between tomb orientation and both environmental factors and sociocultural dynamics.The findings suggest a deliberate and methodical approach to the planning and alignment of tombs during the Neolithic Age.Tomb orientations in each chronological phase displayed clear clustering patterns,reflecting a developmental trajectory from uniformity to diversity,and ultimately toward integration.While early angular measurement techniques appear to have emerged,they do not show evidence of sustained technical progression.Instead,different periods seem to have achieved similar levels of directional accuracy.The predominance of westward-facing tombs may be closely tied to both topographic features and the symbolic association with sunset.At the same time,cultural evolution and interregional exchange played essential roles in shaping the distinctive patterns of prehistoric tomb orientation.This research contributes not only to the understanding of ancient funerary practices but also demonstrates the potential of machine learning and artificial intelligence technologies in advancing archaeological analysis.展开更多
Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(F...Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(FMSs)derived from earthquake data and formation micro-imager(FMI)data from well logs.However,these techniques can be costly,depth-inaccurate,and may lack spatial coverage.To address this issue,we introduce the use of three-dimensional(3D)seismic data(active sources)as a lateral constraint to approximate the 3D stress orientation field.Recognizing that both stress and fracture patterns are closely related to seismic velocity anisotropy,we derive the orientation of azimuthal anisotropy from multi-azimuth 3D seismic data to compensate for the lack of spatial stress orientation information.We apply our proposed workflow to a case study in the Weiyuan area of the Sichuan Basin,China,a region targeted for shale gas production.By integrating diverse datasets,including 3D seismic,earthquakes,and well logs,we develop a comprehensive 3D model of in-situ stress(orientations and magnitudes).Our results demonstrate that the estimated anisotropy orientations from 3D seismic data are consistent with the direction of maximum horizontal principal stress(SHmax)obtained from FMIs.We analyzed 12 earthquakes(magnitude>3)recorded between 2016 and 2020 for their FMSs and compressional axis(P-axis)orientations.The derived SHmax direction from our 3D stress model is 110°ES(East-South),which shows excellent agreement with the FMSs(within 3.96°).This close alignment validates the reliability and precision of our integrated method for predicting 3D SHmax orientations.展开更多
The origin of the misorientations after fcc(face-centered cubic)to hcp(hexagonal close-packed)transformation in pure cobalt was elucidated by utilizing the electron backscatter diffraction(EBSD)technique and transform...The origin of the misorientations after fcc(face-centered cubic)to hcp(hexagonal close-packed)transformation in pure cobalt was elucidated by utilizing the electron backscatter diffraction(EBSD)technique and transformation crystallographic models.It is found the Shoji−Nishiyama orientation relationship during fcc→hcp transformation leads to four hcp variants,characterized by a common misorientation angle of 70.5°with respect to the<1120>direction,which is the predominant misorientation observed.Other statistically significant misorientation angles between hcp grains,including 32°,36°,38°,60°,71°and 86°−91°,are also identified.These newly observed misorientation angles are linked to the microstructure of the fcc matrix at elevated temperatures,with twin structures in the fcc matrix being the primary cause.Furthermore,a novel method is proposed for estimating the fraction of twins in the fcc grains based on misorientation angles between hcp variants,which is found to be consistent with experimental observations.In-situ EBSD observations validate the possible origin of fcc twins from the hcp→fcc transformation.展开更多
This paper presents a deep learning Convolutional Neural Network(CNN)for predicting grain orientations from electron backscatter diffraction(EBSD)patterns.The proposed model consists of multiple neural network layers ...This paper presents a deep learning Convolutional Neural Network(CNN)for predicting grain orientations from electron backscatter diffraction(EBSD)patterns.The proposed model consists of multiple neural network layers and has been trained on a dataset of EBSD patterns obtained from stainless steel 316(SS316).Grain orientation changes when considering the effects of temperature and strain rate on material deformation.The deep learning CNN predicts material orientation using the EBSD method to address this challenge.The accuracy of this approach is evaluated by comparing the predicted crystal orientation with the actual orientation under different conditions,using the Root-Mean-Square Error(RMSE)as the measure.Results show that changing the temperature causes different grain orientations to form,meeting the requirements.Further investigations were conducted to validate the results.展开更多
The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving ...The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving seismic design to mitigate earthquake-induced damages and enhance structural performance. In this study, a specific reinforced concrete (RC) frame structure at Kyungpook National University, designed for educational purposes, is analyzed as a representative case. Utilizing SAP 2000, the research conducts a nonlinear time history analysis to assess the structural performance under seismic conditions. The primary objective is to evaluate the influence of different column section designs, while maintaining identical column section areas, on structural behavior. The study employs two distinct seismic waves from Abeno (ABN) and Takatori (TKT) for the analysis, comparing the structural performance under varying seismic conditions. Key aspects examined include displacement, base shear force, base moment, joint radians, and layer displacement angle. This research is anticipated to serve as a valuable reference for seismic restraint reinforcement work on RC buildings, enriching the methods used for evaluating structures through nonlinear time history analysis based on the synthetic seismic wave approach.展开更多
Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of ...Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.展开更多
Based on learning motivation theory and metacognitive theory, the present study reports questionnaire surveys on correlation between motivation orientations and listening metacognitive strategies among 117 English maj...Based on learning motivation theory and metacognitive theory, the present study reports questionnaire surveys on correlation between motivation orientations and listening metacognitive strategies among 117 English majors. Findings suggest that: 1) English majors are mainly stimulated by instrumental motivation and show bias towards planning and evaluation strategy in listening comprehension; 2) there is a significant positive correlation between instrumental motivation and strategy of planning and evaluation; 3) significant difference between high motive group and low motive group only exists in planning and evaluation strategy. Therefore, teachers are encouraged to help students strengthen the training of listening metacognitive strategies form long-lasting motivation and promote listening proficiency as well as self-learning ability.展开更多
Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations o...Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations of these stresses for grains in various crystallographic orientations have been made for seven BCC transition metals Cr, Fe, Mo, Nb, Ta, V and W. Neglecting W, which is isotropic and the stresses are equiaxial and without grain orientation （hkl） dependence, the BCC metals may be grouped into two classes. In the first class （Cr, Mo, Nb and V）, the （100）-oriented grains have the largest stresses, while the stresses σ1 and σ2 in other （hkl）-oriented grains decrease linearly with the increase of the angle between （hkl） and （100）, and with σ1 〈 σ2 except in （100）- and （lll）-oriented grains. In the second class （Fe and Ta）, on the contrary, the （100）-oriented grains have the lowest stresses, and the stresses σ1 and σ2 in other （hkl）-oriented grains increase linearly with the increase of the angle between （hkl） and （100）, and with σ1 〉 σ2 except in （100）- and （111）-oriented grains.展开更多
This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be ...This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube＇s diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure.展开更多
Perovskite film quality is a decisive factor governing the performance and long-term stability of perovskite solar cells(PSCs). To passivate defects for high-quality perovskite films, various additives have been explo...Perovskite film quality is a decisive factor governing the performance and long-term stability of perovskite solar cells(PSCs). To passivate defects for high-quality perovskite films, various additives have been explored in perovskite precursor with notable achievements in the development of highperformance PSCs. Herein, tartaric acid(TA) was applied as additive in perovskite precursor solution to modulate the crystal growth leading to high quality thin films with enhanced multiple preferential orientations favoring efficient charge transport along multiple directions. It is also noticed that TA can improve the energy level alignment in PSCs, which effectively accelerates both carrier extraction and transportation with non-radiative recombination suppressed at the perovskite interfaces. Based on the present perovskite films, the fabricated PSCs achieved an excellent champion power conversion efficiency(PCE) of 21.82% from that of 19.70% for the control device without TA additive. In addition, a PSC with TA additive was shown to exhibit impressive operational stability by retaining 92% of its initial PCE after~1200 h of aging at room temperature in ambient air with a relative humidity of about 10%–25%. In summary, the present work demonstrates a facile and versatile approach by using TA as additive in perovskite precursor to fabricate high quality perovskite films with enhanced multiple preferential orientations for high-efficiency stable PSCs.展开更多
The understanding of the influence of electrode characteristics on charge transport is essential in the field of molecular electronics.In this work,we investigate the electronic transport properties of molecular junct...The understanding of the influence of electrode characteristics on charge transport is essential in the field of molecular electronics.In this work,we investigate the electronic transport properties of molecular junctions comprising methylthiolterminated permethyloligosilanes and face-centered crystal Au/Ag electrodes with crystallographic orientations of(111)and(100),based on the ab initio quantum transport simulations.The calculations reveal that the molecular junction conductance is dominated by the electronic coupling between two interfacial metal–S bonding states,which can be tuned by varying the molecular length,metal material of the electrodes,and crystallographic orientation.As the permethyloligosilane backbone elongates,although theσconjugation increases,the decreasing of coupling induced by the increasing number of central Si atoms reduces the junction conductance.The molecular junction conductance of methylthiol-terminated permethyloligosilanes with Au electrodes is higher than that with Ag electrodes with a crystallographic orientation of(111).However,the conductance trend is reversed when the electrode crystallographic orientation varies from(111)to(100),which can be ascribed to the reversal of interfacial coupling between two metal–S interfacial states.These findings are conducive to elucidating the mechanism of molecular junctions and improving the transport properties of molecular devices by adjusting the electrode characteristics.展开更多
Molecular packing patterns are crucial factors determining electron/energy transfer processes that are critical for the optoelectronic properties of organic thin film devices.Herein,the polarization-selective ultravio...Molecular packing patterns are crucial factors determining electron/energy transfer processes that are critical for the optoelectronic properties of organic thin film devices.Herein,the polarization-selective ultraviolet/infrared(UV/IR)mixed frequency ultrafast spectroscopy is applied to investigate the relative molecular orientations in two organic thin films of 7-(diethylamino)coumarin-3-carboxylic acid(DEAC)and perylene.The signal anisotropy changes caused by intermolecular energy/electron transfers are utilized to calculate the cross angles between the electronic transition dipole moment of the donor and the vibrational transition dipole moments of the acceptor,yielding the relative orientation between two adjacent molecules.Using this method,the relative orientation angle in DEAC film is determined to be 53.4°,close to 60°of its single crystalline structure,and that of the perylene film is determined to be 6.2°,also close to-0.2°of its single crystalline structure.Besides experimental uncertainties,the small difference between the angles determined by this method and those of single crystals also results from the fact that the thin film samples are polycrystalline where some of the molecules are amorphous.展开更多
Ancient Egyptians change the orientation of their temples from True East （during the old kingdom） to the Winter Solstice （during the new kingdom）, because of the cultic change from a rather pure solar to a mixed s...Ancient Egyptians change the orientation of their temples from True East （during the old kingdom） to the Winter Solstice （during the new kingdom）, because of the cultic change from a rather pure solar to a mixed solar religion （R^a to Amfin-R^a）. The traditional methods for measuring the orientations and alignment, the axis of ancient Egyptian constructions like field survey are usually time consuming and costly. Remote sensing techniques are becoming powerful tools for archaeologists in their discovery and exploration ancient sites. Many researchers have considered very high resolution sensors, especially IKONOS with 1.0 m resolution, QuickBird with 0.61 m resolution and Geoeye-1 with 0.50 m resolutions as possible substitutes of the classical aerial photos used for multi purposes such as cartographic at large scales. Research objectives is to establish a practical methodology for calculation the orientation of the main axis of the ancient Egyptian temple based on very high resolution QuickBird images as alternative for traditional methods. Five sites have been selected to perform our research lies in Luxor city, Egypt： Luxor, Karnak, Hatshepsut, Ramesseum temples and Madinat Habu. Analysis of the obtained results has been done to explain the type of orientation of Luxor temples. Previous archaeologist＇s studies classified the orientation of ancient Egyptians constructions into astronomical orientation （solar, moon and stars） or topographical orientation （Nile direction and hills） or both. A comparative study has been done between the results obtained from traditional methods （field survey and Google Earth images） and from very high resolution QuickBird satellite images. From the obtained results, error in the main axis azimuth of Luxor, Karnak, Madinat Habu, Hatshepsut and Ramesseum temples range about minutes of are. One can concluded that using VHR （Very High Resolution） QuickBird satellite images in calculation the azimuth of ancient sites is the accurate method.展开更多
Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is c...Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets.展开更多
As a key predictor of learners’language achievement,motivation has long been an active research area in second language acquisition.Among assorted theories,Gardner’s perspective is one of the foundations of L2 motiv...As a key predictor of learners’language achievement,motivation has long been an active research area in second language acquisition.Among assorted theories,Gardner’s perspective is one of the foundations of L2 motivation research and thus has dominated this field for a long time.Do?rnye later put forward the L2 Motivational Self System to reconceptualise Gardner’s notions.The current essay attempts to reflect on the concepts of integrative and instrumental motivational orientations discussed in both Gardner’s and Do?rnyei’s theoretical frameworks in order to gain a subtler understanding of the role of these two notions in L2 motivation.展开更多
The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersio...The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) 1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Alplane in the form of corrosion bands.展开更多
The static recrystallization process of a cold-rolled Mg-Zn-Gd alloy was tracked by a quasi-in-situ electron backscatter diffraction method to investigate the orientations of nuclei.The results show that orientation d...The static recrystallization process of a cold-rolled Mg-Zn-Gd alloy was tracked by a quasi-in-situ electron backscatter diffraction method to investigate the orientations of nuclei.The results show that orientation distribution of nuclei is associated with nucleation mechanism.The continuous static recrystallization nuclei display similar orientations to the parent grains with TD orientation.Differently,discontinuous static recrystallization nuclei formed within the parent grains(TD-45~0 orientation) show random orientations and a variety of misorientation angles but preferred axes <5273> or <5270>.Interestingly,a special oriented nucleation is found.Discontinuous static recrystallization nuclei originated from boundaries of the parent grain(TD-70° orientation) show concentrated TD orientations in another side due to the preferred misorientation relationship 70°<1120>(∑18 b).It is speculated that these two special misorientation relationships are related to the dislocation type.展开更多
The adsorption and molecular orientation of Dy@Cs2 isomer I on Au（111） has been investigated using ultrahigh-vacuum scanning tunneling microscopy at 80 K. At low coverages, the Dy@Cs2 molecules tend to grow along th...The adsorption and molecular orientation of Dy@Cs2 isomer I on Au（111） has been investigated using ultrahigh-vacuum scanning tunneling microscopy at 80 K. At low coverages, the Dy@Cs2 molecules tend to grow along the step edges of Au（111）, forming small clusters and molecular chains. Adsorption of Dy@Cs2 on the edges is dominated by the fullerene-substrate interaction and presents various molecular orientations. At higher coverages, the Dy@Cs2 is found to form ordered islands consisting of small domains of equally oriented molecules. The Dy@Cs2 molecules in the islands prefer the adsorption configurations with the major C2 axis being approximately parallel to the surface of the substrate. Three preferable orientations of the Dy@Cs2 molecules are found in a two-dimensional hexagonal close packed overlayer. These observations are attributed to the interplay of the fullerene-substrate interaction and dipole-dipole interaction between the metallofullerenes.展开更多
Strain-induced martensites in high manganese TRIP/TWIP steels were investigated in the presence of thermal martensites and under the influence of austenitic grain orientation by X-ray diffraction （XRD）, scanning ele...Strain-induced martensites in high manganese TRIP/TWIP steels were investigated in the presence of thermal martensites and under the influence of austenitic grain orientation by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electron backscattered diffraction （EBSD）. Before deformation, the morphology of α＇- M depended mainly on the number of variants and growing period. Regardless of martensite morphologies and deformation, the Kurdjumov-Sachs （K-S） orientation relationships always maintained. The 6 α＇-M variants formed from a plate of ε-M were of 3 pairs of twins with a common axis 〈110〉α＇ parallel to the normal of {112}γ habit plane to minimize transformation strain. When α＇-M could be formed only by deformation, it nucleated at the intersection of ε-M variants and grew mainly in thick ε-M plates. Thick ε plates promoted significantly the α＇-M and weakened the influence of grain orientations. During tension, the transformation in 〈100〉-oriented grains was observed to be slower than that in 〈121〉-oriented grains. Deformation twins promoted ε-M formation slightly and had no apparent effect on α＇-M. Deformation increased the number of ε-M variants, but reduced that of α＇-M variants.展开更多
On the basis of research method in FTIR imaging, we made a heterogeneous thin film of isotactic polypropylene （iPP） that contains a few large spherulites （-150 μm） which are surrounded by small spherulites （-15 ...On the basis of research method in FTIR imaging, we made a heterogeneous thin film of isotactic polypropylene （iPP） that contains a few large spherulites （-150 μm） which are surrounded by small spherulites （-15 μm） for tensile testing. The evolution processes of crystalline and amorphous orientations of iPP are monitored with its characteristic peaks at 998 and 973 cm^-1, respectively. By introducing the correlation images, the analysis demonstrates the relationships between the orientation evolutions of crystalline and amorphous phases in a space of 250 μm × 250 μm detecting area. During the plastic deformation, crystalline orientation is higher than amorphous orientation outside the large spherulite, while that is opposite inside the region. In addition, the evolutions of crystalline and amorphous orientations almost keep a positive correlation.展开更多
基金The Basic Scientific Research of Henan Academy of Sciences,No.20250601010National Natural Science Foundation of China,No.41971016+2 种基金The Innovation Team Project of Henan Academy of Sciences,No.20230103Science and Technology Innovation Platform Cultivation and Promotion Project of Henan Academy of Sciences,No.241001037The Soft Science Project of Henan Province,No.252400410524。
文摘The orientations of ancient tombs have attracted increasing scholarly attention,as they offer valuable insights into early social structures,cultural traditions,and the relationship between humans and their environment.However,the application of machine learning algorithms to the study of tomb orientation remains relatively underexplored.In this study,we employed a Gaussian mixture model to conduct a systematic analysis of the spatial and temporal evolution of Neolithic tomb orientations in Central China.We also examined the relationship between tomb orientation and both environmental factors and sociocultural dynamics.The findings suggest a deliberate and methodical approach to the planning and alignment of tombs during the Neolithic Age.Tomb orientations in each chronological phase displayed clear clustering patterns,reflecting a developmental trajectory from uniformity to diversity,and ultimately toward integration.While early angular measurement techniques appear to have emerged,they do not show evidence of sustained technical progression.Instead,different periods seem to have achieved similar levels of directional accuracy.The predominance of westward-facing tombs may be closely tied to both topographic features and the symbolic association with sunset.At the same time,cultural evolution and interregional exchange played essential roles in shaping the distinctive patterns of prehistoric tomb orientation.This research contributes not only to the understanding of ancient funerary practices but also demonstrates the potential of machine learning and artificial intelligence technologies in advancing archaeological analysis.
基金supported by the National Key R&D Program of China(Grant No.2020YFA0710604)NSFC(Grant No.42374064).
文摘Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(FMSs)derived from earthquake data and formation micro-imager(FMI)data from well logs.However,these techniques can be costly,depth-inaccurate,and may lack spatial coverage.To address this issue,we introduce the use of three-dimensional(3D)seismic data(active sources)as a lateral constraint to approximate the 3D stress orientation field.Recognizing that both stress and fracture patterns are closely related to seismic velocity anisotropy,we derive the orientation of azimuthal anisotropy from multi-azimuth 3D seismic data to compensate for the lack of spatial stress orientation information.We apply our proposed workflow to a case study in the Weiyuan area of the Sichuan Basin,China,a region targeted for shale gas production.By integrating diverse datasets,including 3D seismic,earthquakes,and well logs,we develop a comprehensive 3D model of in-situ stress(orientations and magnitudes).Our results demonstrate that the estimated anisotropy orientations from 3D seismic data are consistent with the direction of maximum horizontal principal stress(SHmax)obtained from FMIs.We analyzed 12 earthquakes(magnitude>3)recorded between 2016 and 2020 for their FMSs and compressional axis(P-axis)orientations.The derived SHmax direction from our 3D stress model is 110°ES(East-South),which shows excellent agreement with the FMSs(within 3.96°).This close alignment validates the reliability and precision of our integrated method for predicting 3D SHmax orientations.
基金supported by the National Key R&D Program of China(No.2022YFB3504403).
文摘The origin of the misorientations after fcc(face-centered cubic)to hcp(hexagonal close-packed)transformation in pure cobalt was elucidated by utilizing the electron backscatter diffraction(EBSD)technique and transformation crystallographic models.It is found the Shoji−Nishiyama orientation relationship during fcc→hcp transformation leads to four hcp variants,characterized by a common misorientation angle of 70.5°with respect to the<1120>direction,which is the predominant misorientation observed.Other statistically significant misorientation angles between hcp grains,including 32°,36°,38°,60°,71°and 86°−91°,are also identified.These newly observed misorientation angles are linked to the microstructure of the fcc matrix at elevated temperatures,with twin structures in the fcc matrix being the primary cause.Furthermore,a novel method is proposed for estimating the fraction of twins in the fcc grains based on misorientation angles between hcp variants,which is found to be consistent with experimental observations.In-situ EBSD observations validate the possible origin of fcc twins from the hcp→fcc transformation.
文摘This paper presents a deep learning Convolutional Neural Network(CNN)for predicting grain orientations from electron backscatter diffraction(EBSD)patterns.The proposed model consists of multiple neural network layers and has been trained on a dataset of EBSD patterns obtained from stainless steel 316(SS316).Grain orientation changes when considering the effects of temperature and strain rate on material deformation.The deep learning CNN predicts material orientation using the EBSD method to address this challenge.The accuracy of this approach is evaluated by comparing the predicted crystal orientation with the actual orientation under different conditions,using the Root-Mean-Square Error(RMSE)as the measure.Results show that changing the temperature causes different grain orientations to form,meeting the requirements.Further investigations were conducted to validate the results.
文摘The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving seismic design to mitigate earthquake-induced damages and enhance structural performance. In this study, a specific reinforced concrete (RC) frame structure at Kyungpook National University, designed for educational purposes, is analyzed as a representative case. Utilizing SAP 2000, the research conducts a nonlinear time history analysis to assess the structural performance under seismic conditions. The primary objective is to evaluate the influence of different column section designs, while maintaining identical column section areas, on structural behavior. The study employs two distinct seismic waves from Abeno (ABN) and Takatori (TKT) for the analysis, comparing the structural performance under varying seismic conditions. Key aspects examined include displacement, base shear force, base moment, joint radians, and layer displacement angle. This research is anticipated to serve as a valuable reference for seismic restraint reinforcement work on RC buildings, enriching the methods used for evaluating structures through nonlinear time history analysis based on the synthetic seismic wave approach.
文摘Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.
文摘Based on learning motivation theory and metacognitive theory, the present study reports questionnaire surveys on correlation between motivation orientations and listening metacognitive strategies among 117 English majors. Findings suggest that: 1) English majors are mainly stimulated by instrumental motivation and show bias towards planning and evaluation strategy in listening comprehension; 2) there is a significant positive correlation between instrumental motivation and strategy of planning and evaluation; 3) significant difference between high motive group and low motive group only exists in planning and evaluation strategy. Therefore, teachers are encouraged to help students strengthen the training of listening metacognitive strategies form long-lasting motivation and promote listening proficiency as well as self-learning ability.
基金Project supported by the State Key Development Programme for Basic Research of China （Grant No 2004CB619302）, and the National Natural Science Foundation of China （Grant No 50271038）.
文摘Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations of these stresses for grains in various crystallographic orientations have been made for seven BCC transition metals Cr, Fe, Mo, Nb, Ta, V and W. Neglecting W, which is isotropic and the stresses are equiaxial and without grain orientation （hkl） dependence, the BCC metals may be grouped into two classes. In the first class （Cr, Mo, Nb and V）, the （100）-oriented grains have the largest stresses, while the stresses σ1 and σ2 in other （hkl）-oriented grains decrease linearly with the increase of the angle between （hkl） and （100）, and with σ1 〈 σ2 except in （100）- and （lll）-oriented grains. In the second class （Fe and Ta）, on the contrary, the （100）-oriented grains have the lowest stresses, and the stresses σ1 and σ2 in other （hkl）-oriented grains increase linearly with the increase of the angle between （hkl） and （100）, and with σ1 〉 σ2 except in （100）- and （111）-oriented grains.
基金Supported by the National Basic Research Program of China under Grant No 2011CB808200the National Natural Science Foundation of China under Grant Nos 11504150,11304020 and 51320105007the Cheung Kong Scholars Programme of China
文摘This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube＇s diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure.
基金supported by the National Key Research and Development Program of China 2017YFA0403403 and 2017YFB0701901the Natural Science Foundation of China 12075303, 11675252 and U1632265。
文摘Perovskite film quality is a decisive factor governing the performance and long-term stability of perovskite solar cells(PSCs). To passivate defects for high-quality perovskite films, various additives have been explored in perovskite precursor with notable achievements in the development of highperformance PSCs. Herein, tartaric acid(TA) was applied as additive in perovskite precursor solution to modulate the crystal growth leading to high quality thin films with enhanced multiple preferential orientations favoring efficient charge transport along multiple directions. It is also noticed that TA can improve the energy level alignment in PSCs, which effectively accelerates both carrier extraction and transportation with non-radiative recombination suppressed at the perovskite interfaces. Based on the present perovskite films, the fabricated PSCs achieved an excellent champion power conversion efficiency(PCE) of 21.82% from that of 19.70% for the control device without TA additive. In addition, a PSC with TA additive was shown to exhibit impressive operational stability by retaining 92% of its initial PCE after~1200 h of aging at room temperature in ambient air with a relative humidity of about 10%–25%. In summary, the present work demonstrates a facile and versatile approach by using TA as additive in perovskite precursor to fabricate high quality perovskite films with enhanced multiple preferential orientations for high-efficiency stable PSCs.
基金the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2019PA022)the National Natural Science Foundation of China(Grant No.21933002)。
文摘The understanding of the influence of electrode characteristics on charge transport is essential in the field of molecular electronics.In this work,we investigate the electronic transport properties of molecular junctions comprising methylthiolterminated permethyloligosilanes and face-centered crystal Au/Ag electrodes with crystallographic orientations of(111)and(100),based on the ab initio quantum transport simulations.The calculations reveal that the molecular junction conductance is dominated by the electronic coupling between two interfacial metal–S bonding states,which can be tuned by varying the molecular length,metal material of the electrodes,and crystallographic orientation.As the permethyloligosilane backbone elongates,although theσconjugation increases,the decreasing of coupling induced by the increasing number of central Si atoms reduces the junction conductance.The molecular junction conductance of methylthiol-terminated permethyloligosilanes with Au electrodes is higher than that with Ag electrodes with a crystallographic orientation of(111).However,the conductance trend is reversed when the electrode crystallographic orientation varies from(111)to(100),which can be ascribed to the reversal of interfacial coupling between two metal–S interfacial states.These findings are conducive to elucidating the mechanism of molecular junctions and improving the transport properties of molecular devices by adjusting the electrode characteristics.
基金supported by Ministry of Science and Technology of China(No.2017YFA0204702)the National Natural Science Foundation of China(No.21627805,No.21673004,No.21804004,and No.21821004)。
文摘Molecular packing patterns are crucial factors determining electron/energy transfer processes that are critical for the optoelectronic properties of organic thin film devices.Herein,the polarization-selective ultraviolet/infrared(UV/IR)mixed frequency ultrafast spectroscopy is applied to investigate the relative molecular orientations in two organic thin films of 7-(diethylamino)coumarin-3-carboxylic acid(DEAC)and perylene.The signal anisotropy changes caused by intermolecular energy/electron transfers are utilized to calculate the cross angles between the electronic transition dipole moment of the donor and the vibrational transition dipole moments of the acceptor,yielding the relative orientation between two adjacent molecules.Using this method,the relative orientation angle in DEAC film is determined to be 53.4°,close to 60°of its single crystalline structure,and that of the perylene film is determined to be 6.2°,also close to-0.2°of its single crystalline structure.Besides experimental uncertainties,the small difference between the angles determined by this method and those of single crystals also results from the fact that the thin film samples are polycrystalline where some of the molecules are amorphous.
文摘Ancient Egyptians change the orientation of their temples from True East （during the old kingdom） to the Winter Solstice （during the new kingdom）, because of the cultic change from a rather pure solar to a mixed solar religion （R^a to Amfin-R^a）. The traditional methods for measuring the orientations and alignment, the axis of ancient Egyptian constructions like field survey are usually time consuming and costly. Remote sensing techniques are becoming powerful tools for archaeologists in their discovery and exploration ancient sites. Many researchers have considered very high resolution sensors, especially IKONOS with 1.0 m resolution, QuickBird with 0.61 m resolution and Geoeye-1 with 0.50 m resolutions as possible substitutes of the classical aerial photos used for multi purposes such as cartographic at large scales. Research objectives is to establish a practical methodology for calculation the orientation of the main axis of the ancient Egyptian temple based on very high resolution QuickBird images as alternative for traditional methods. Five sites have been selected to perform our research lies in Luxor city, Egypt： Luxor, Karnak, Hatshepsut, Ramesseum temples and Madinat Habu. Analysis of the obtained results has been done to explain the type of orientation of Luxor temples. Previous archaeologist＇s studies classified the orientation of ancient Egyptians constructions into astronomical orientation （solar, moon and stars） or topographical orientation （Nile direction and hills） or both. A comparative study has been done between the results obtained from traditional methods （field survey and Google Earth images） and from very high resolution QuickBird satellite images. From the obtained results, error in the main axis azimuth of Luxor, Karnak, Madinat Habu, Hatshepsut and Ramesseum temples range about minutes of are. One can concluded that using VHR （Very High Resolution） QuickBird satellite images in calculation the azimuth of ancient sites is the accurate method.
文摘Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets.
文摘As a key predictor of learners’language achievement,motivation has long been an active research area in second language acquisition.Among assorted theories,Gardner’s perspective is one of the foundations of L2 motivation research and thus has dominated this field for a long time.Do?rnye later put forward the L2 Motivational Self System to reconceptualise Gardner’s notions.The current essay attempts to reflect on the concepts of integrative and instrumental motivational orientations discussed in both Gardner’s and Do?rnyei’s theoretical frameworks in order to gain a subtler understanding of the role of these two notions in L2 motivation.
基金the financial support from the National Natural Science Foundation of China (No. 51961013)the Natural Science Foundation of Jiangxi Province, China (No. 20202ACBL214002)+2 种基金the China Postdoctoral Science Foundation (Nos. 2019M660159 and 2020T130093)the Postdoctoral Science Foundation of Jiangxi Province, China (No. 2019KY25)the Program of Qingjiang Excellent Young Talents of Jiangxi University of Science and Technology, China (No. JXUSTQJYX2020022)。
文摘The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) 1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Alplane in the form of corrosion bands.
基金the financial supports from the National Natural Science Foundation of China(NSFC,No.51601193)State Key Program of National Natural Science of China(No.51531002)+1 种基金National Key Research and Development Program of China(No.2016YFB0301104)National Basic Research Program of China(973 Program,No.2013CB632202)。
文摘The static recrystallization process of a cold-rolled Mg-Zn-Gd alloy was tracked by a quasi-in-situ electron backscatter diffraction method to investigate the orientations of nuclei.The results show that orientation distribution of nuclei is associated with nucleation mechanism.The continuous static recrystallization nuclei display similar orientations to the parent grains with TD orientation.Differently,discontinuous static recrystallization nuclei formed within the parent grains(TD-45~0 orientation) show random orientations and a variety of misorientation angles but preferred axes <5273> or <5270>.Interestingly,a special oriented nucleation is found.Discontinuous static recrystallization nuclei originated from boundaries of the parent grain(TD-70° orientation) show concentrated TD orientations in another side due to the preferred misorientation relationship 70°<1120>(∑18 b).It is speculated that these two special misorientation relationships are related to the dislocation type.
基金V. ACKNOWLEDGMENTS We thank Professor Shi-he Yang from the Hong Kong University of Science and Technology for supplying Dy@Cs2. This work is supported by the National Natural Science Foundation of China （No.10825415）.
文摘The adsorption and molecular orientation of Dy@Cs2 isomer I on Au（111） has been investigated using ultrahigh-vacuum scanning tunneling microscopy at 80 K. At low coverages, the Dy@Cs2 molecules tend to grow along the step edges of Au（111）, forming small clusters and molecular chains. Adsorption of Dy@Cs2 on the edges is dominated by the fullerene-substrate interaction and presents various molecular orientations. At higher coverages, the Dy@Cs2 is found to form ordered islands consisting of small domains of equally oriented molecules. The Dy@Cs2 molecules in the islands prefer the adsorption configurations with the major C2 axis being approximately parallel to the surface of the substrate. Three preferable orientations of the Dy@Cs2 molecules are found in a two-dimensional hexagonal close packed overlayer. These observations are attributed to the interplay of the fullerene-substrate interaction and dipole-dipole interaction between the metallofullerenes.
基金funded by the National Natural Science Foundation of China (No. 50771019)Specialized Research Fund for the Doctoral Program of Higher Education (No. 20090006110013)
文摘Strain-induced martensites in high manganese TRIP/TWIP steels were investigated in the presence of thermal martensites and under the influence of austenitic grain orientation by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electron backscattered diffraction （EBSD）. Before deformation, the morphology of α＇- M depended mainly on the number of variants and growing period. Regardless of martensite morphologies and deformation, the Kurdjumov-Sachs （K-S） orientation relationships always maintained. The 6 α＇-M variants formed from a plate of ε-M were of 3 pairs of twins with a common axis 〈110〉α＇ parallel to the normal of {112}γ habit plane to minimize transformation strain. When α＇-M could be formed only by deformation, it nucleated at the intersection of ε-M variants and grew mainly in thick ε-M plates. Thick ε plates promoted significantly the α＇-M and weakened the influence of grain orientations. During tension, the transformation in 〈100〉-oriented grains was observed to be slower than that in 〈121〉-oriented grains. Deformation twins promoted ε-M formation slightly and had no apparent effect on α＇-M. Deformation increased the number of ε-M variants, but reduced that of α＇-M variants.
基金financially supported by the China Postdoctoral Science Foundation(No.2012M521233)the Fundamental Research Funds for the Central Universities(No.WK2310000031)+1 种基金the National Natural Science Funds for Distinguished Young Scholar(No.51325301)973 program of MOST(No.2010CB934504)
文摘On the basis of research method in FTIR imaging, we made a heterogeneous thin film of isotactic polypropylene （iPP） that contains a few large spherulites （-150 μm） which are surrounded by small spherulites （-15 μm） for tensile testing. The evolution processes of crystalline and amorphous orientations of iPP are monitored with its characteristic peaks at 998 and 973 cm^-1, respectively. By introducing the correlation images, the analysis demonstrates the relationships between the orientation evolutions of crystalline and amorphous phases in a space of 250 μm × 250 μm detecting area. During the plastic deformation, crystalline orientation is higher than amorphous orientation outside the large spherulite, while that is opposite inside the region. In addition, the evolutions of crystalline and amorphous orientations almost keep a positive correlation.
