The English writing is a fundamental and critical skill for English learners who they perform disatisfactorily in both classrooms and national writing tests. Culture Mode is hereby proposed The mode proposed is consis...The English writing is a fundamental and critical skill for English learners who they perform disatisfactorily in both classrooms and national writing tests. Culture Mode is hereby proposed The mode proposed is consisted of two parts: the compilation of reading materials and the reform of teaching process. An action research is conducted and interview is held to explore the efficacy of it to stimulate the students' interests in writing by reading crossculturally, to develop their writing skills by recording their daily life or their observation of the society, to cultivate their critical thinking by writing responses after each session of practice.展开更多
Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensiona...Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing disasters.Therefore,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is proposed.True triaxial static compression and intermittent disturbance tests are carried out on monzogabbro.The effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture mechanism.Rapid increases in microseismic parameters during rock loading can be precursors for intermittent rock disturbance.Based on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental results.The sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are predicted.This study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.展开更多
Years go by and seasons flow.At this moment of waving goodbye to the unforgettable year of 2022 and welcoming the Spring Festival of the Year 2023,the Year of the Rabbit,we would like to send our sincere thanks and be...Years go by and seasons flow.At this moment of waving goodbye to the unforgettable year of 2022 and welcoming the Spring Festival of the Year 2023,the Year of the Rabbit,we would like to send our sincere thanks and best wishes for the new year to experts,authors,readers of our Journal and friends from all fields!展开更多
Given that speaking plays a fundamental role in writing, this paper reports on a one-year program of the training of student writers. This training program consists of three parts: a pre-training investigation over l...Given that speaking plays a fundamental role in writing, this paper reports on a one-year program of the training of student writers. This training program consists of three parts: a pre-training investigation over learners' needs and expectations, various forms of the pre-writing discussions over different stages of the program, and a post-training investigation to get the feedback from the learners.展开更多
Writer identity in academic writing has long been ignored by developing L2 writers.Moreover,research has much focused on the reader in shaping writing,and treated the role of the writer as unproblematic.In this essay,...Writer identity in academic writing has long been ignored by developing L2 writers.Moreover,research has much focused on the reader in shaping writing,and treated the role of the writer as unproblematic.In this essay,the construction of writer identity in developing writers’academic writing practice will be explored through a review of some relevant literature research and gain insights for the development of writer apprentices and writing instruction.展开更多
Academic writing is social interaction between writer and reader,during which writers can employ discursive and non-discursive features to construct their identities.However,many student writers who are users of Engli...Academic writing is social interaction between writer and reader,during which writers can employ discursive and non-discursive features to construct their identities.However,many student writers who are users of English as an additional language(EAL)may find it challenging to construct their identities in academic writing.Properly constructed identity in academic writing can help EAL student writers develop a stronger sense of self,exercise their agency,and negotiate the academic discourse.Therefore,this paper reviews empirical studies on EAL student writers'identity construction when they write in English to investigate the features of identities that EAL student writers construct in texts and the factors that influence their identity construction.The findings show that,compared with expert writers and native-English-speaking(NES)counterparts,EAL student writers tend to present a weak authorial identity.Furthermore,EAL student writers tend to be more engaged with texts than with readers and lack commitment to their claims.The identities that EAL student writers construct in academic writing are also interwoven with EAL students'English proficiency levels,educational experience,disciplinary conventions,genre affordances,and audience awareness.The findings of this literature review can help teachers and educators raise EAL students’identity awareness and facilitate students in strategically constructing writer identities in academic writing.展开更多
Large Language Models(LLMs),exemplified by ChatGPT,have significantly reshaped text generation,particularly in the realm of writing assistance.While ethical considerations underscore the importance of transparently ac...Large Language Models(LLMs),exemplified by ChatGPT,have significantly reshaped text generation,particularly in the realm of writing assistance.While ethical considerations underscore the importance of transparently acknowledging LLM use,especially in scientific communication,genuine acknowledgment remains infrequent.A potential avenue to encourage accurate acknowledging of LLM-assisted writing involves employing automated detectors.Our evaluation of four cutting-edge LLM-generated text detectors reveals their suboptimal performance compared to a simple ad-hoc detector designed to identify abrupt writing style changes around the time of LLM proliferation.We contend that the development of specialized detectors exclusively dedicated to LLM-assisted writing detection is necessary.Such detectors could play a crucial role in fostering more authentic recognition of LLM involvement in scientific communication,addressing the current challenges in acknowledgment practices.展开更多
Writer/reader(W/R) visibility is regarded as an important indicator of personal involvement. Previous studies concluded that EFL learners tend to contains more personal involvement than native speakers in their writin...Writer/reader(W/R) visibility is regarded as an important indicator of personal involvement. Previous studies concluded that EFL learners tend to contains more personal involvement than native speakers in their writing, making it resemble spoken language as a result. Therefore, this paper examines the degree of W/R visibility in English writing by university-level Chinese learners to verify the applicability of the previous findings on Chinese learners. Based on the data collected in the corpora CLEC,WECCL and LOCNESS, the results show that Chinese EFL learners have the tendency to employ more features of W/R visibility than native speakers, for example the high use of first or second person reference and words that represent mental process. Besides, the paper also reveals little distinction on W/R visibility between English and non-English majors, suggesting the inefficiency of the writing ability of today's English majors.展开更多
Revision is a complex,yet important phase in writing to improve the quality of a text.Some revision models are created to explain its components and the ways these components work.However,analysis of available models ...Revision is a complex,yet important phase in writing to improve the quality of a text.Some revision models are created to explain its components and the ways these components work.However,analysis of available models shows that they are proposed mainly for expert writers,who can complete the complex revision process individually,without the need of support or feedback.Most of the available revision models also do not include audience as a component.Therefore,the purpose of this paper is to introduce an alternative revision model for novice writers at or higher than highschool level with a focus on audience and feedback.First,the definition of revision is made,which is followed by summaries of the importance of audience and feedback in writing.Second,available revision models in literature that serves as the basis of the alternative model are reviewed.Finally,the alternative revision model is introduced with its components and the way these components work is explained.The revision model presented in this paper will contribute to literature on writing by filling the gap in revision models by proposing a model for novice writers and highlighting the importance of audience and feedback.展开更多
The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the...The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the mechanical properties and damage/fracture evolution mechanisms of deep rock induced by microdynamic disturbance under three-dimensional stress states are unclear.Therefore,a true triaxial multilevel disturbance test method is proposed,which can completely simulate natural geostress,excavation stress redistribution(such as stress unloading,concentration and rotation),and subsequently the microdynamic disturbance triggering damaged rock failure.Based on a dynamic true triaxial test platform,true triaxial microdynamic disturbance tests under different frequency and amplitudes were carried out on monzogabbro.The results show that increasing amplitude or decreasing frequency diminishes the failure strength of monzogabbro.Deformation modulus gradually decreases during disturbance failure.As frequency and amplitude increase,the degradation rate of deformation modulus decreases slightly,disturbance dissipated energy increases significantly,and disturbance deformation anisotropy strengthens obviously.A damage model has been proposed to quantitatively characterize the disturbance-induced damage evolution at different frequency and amplitude under true triaxial stress.Before disturbance failure,the micro-tensile crack mechanism is dominant,and the micro-shear crack mechanism increases significantly at failure.With the increase of amplitude and frequency,the micro-shear crack mechanism increases.When approaching disturbance failure,the acoustic emission fractal dimension changes from a stable value to local large oscillation,and finally increases sharply to a high value at failure.Finally,the disturbance-induced failure mechanism of surrounding rock in deep engineering is clearly elucidated.展开更多
Aspan of twenty-five years,for a company,constitutes a engthy and eventful journey.Twenty-five years ago,a group of oil professionals from the Bureau of Geophysical Prospecting INC (hereinafter referred to as BGP),set...Aspan of twenty-five years,for a company,constitutes a engthy and eventful journey.Twenty-five years ago,a group of oil professionals from the Bureau of Geophysical Prospecting INC (hereinafter referred to as BGP),set foot on the land of Nigeria and embarked on a legendary journey.This is a narrative of resilience,commitment,and heartfelt passion,an inspiring saga that touches the soul.展开更多
For all its different forms,democracy is expected to promote people’s well-being,instead of being weaponized to justify hegemony,as democracy is also a principle of global governance.
High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic ...High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.展开更多
The anisotropic mechanical behavior of rocks under high-stress and high-temperature coupled conditions is crucial for analyzing the stability of surrounding rocks in deep underground engineering.This paper is devoted ...The anisotropic mechanical behavior of rocks under high-stress and high-temperature coupled conditions is crucial for analyzing the stability of surrounding rocks in deep underground engineering.This paper is devoted to studying the anisotropic strength,deformation and failure behavior of gneiss granite from the deep boreholes of a railway tunnel that suffers from high tectonic stress and ground temperature in the eastern tectonic knot in the Tibet Plateau.High-temperature true triaxial compression tests are performed on the samples using a self-developed testing device with five different loading directions and three temperature values that are representative of the geological conditions of the deep underground tunnels in the region.Effect of temperature and loading direction on the strength,elastic modulus,Poisson’s ratio,and failure mode are analyzed.The method for quantitative identification of anisotropic failure is also proposed.The anisotropic mechanical behaviors of the gneiss granite are very sensitive to the changes in loading direction and temperature under true triaxial compression,and the high temperature seems to weaken the inherent anisotropy and stress-induced deformation anisotropy.The strength and deformation show obvious thermal degradation at 200℃due to the weakening of friction between failure surfaces and the transition of the failure pattern in rock grains.In the range of 25℃ 200℃,the failure is mainly governed by the loading direction due to the inherent anisotropy.This study is helpful to the in-depth understanding of the thermal-mechanical behavior of anisotropic rocks in deep underground projects.展开更多
China and Malaysia established diplomatic ties fifty years ago.Over the past half-century,the bilateral relationship has made great progress in various fields,delivering tangible benefits to the people of the two coun...China and Malaysia established diplomatic ties fifty years ago.Over the past half-century,the bilateral relationship has made great progress in various fields,delivering tangible benefits to the people of the two countries and making positive contributions to the peace,stability,and prosperity of the region.展开更多
It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this s...It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this study,we demonstrate that using high-numerical-aperture 800 nm femtosecond laser direct writing with controlled pulse energy and scanning speed in the near-damage-threshold regime,polarization-dependent deep-subwavelength single grooves with linewidths of~180 nm can be controllably prepared on Si.Generally,the single-groove linewidth increases slightly with increase in the pulse energy and decrease in the scanning speed,whereas the single-groove depth significantly increases from~300 nm to~600 nm with decrease in the scanning speed,or even to over 1μm with multi-processing,indicating the characteristics of transverse clamping and longitudinal growth of such deep-subwavelength single grooves.Energy dispersive spectroscopy composition analysis of the near-groove region confirms that single-groove formation tends to be an ultrafast,non-thermal ablation process,and the oxidized deposits near the grooves are easy to clean up.Furthermore,the results,showing both the strong dependence of groove orientation on laser polarization and the occurrence of double-groove structures due to the interference of pre-formed orthogonal grooves,indicate that the extraordinary field enhancement of strong polarization sensitivity in the deep-subwavelength groove plays an important role in single-groove growth with high stability and collimation.展开更多
文摘The English writing is a fundamental and critical skill for English learners who they perform disatisfactorily in both classrooms and national writing tests. Culture Mode is hereby proposed The mode proposed is consisted of two parts: the compilation of reading materials and the reform of teaching process. An action research is conducted and interview is held to explore the efficacy of it to stimulate the students' interests in writing by reading crossculturally, to develop their writing skills by recording their daily life or their observation of the society, to cultivate their critical thinking by writing responses after each session of practice.
基金the financial support from the National Natural Science Foundation of China(No.52109119)the Guangxi Natural Science Foundation(No.2021GXNSFBA075030)+2 种基金the Guangxi Science and Technology Project(No.Guike AD20325002)the Chinese Postdoctoral Science Fund Project(No.2022 M723408)the Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(China Institute of Water Resources and Hydropower Research)(No.IWHR-SKL-202202).
文摘Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing disasters.Therefore,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is proposed.True triaxial static compression and intermittent disturbance tests are carried out on monzogabbro.The effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture mechanism.Rapid increases in microseismic parameters during rock loading can be precursors for intermittent rock disturbance.Based on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental results.The sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are predicted.This study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.
文摘Years go by and seasons flow.At this moment of waving goodbye to the unforgettable year of 2022 and welcoming the Spring Festival of the Year 2023,the Year of the Rabbit,we would like to send our sincere thanks and best wishes for the new year to experts,authors,readers of our Journal and friends from all fields!
文摘Given that speaking plays a fundamental role in writing, this paper reports on a one-year program of the training of student writers. This training program consists of three parts: a pre-training investigation over learners' needs and expectations, various forms of the pre-writing discussions over different stages of the program, and a post-training investigation to get the feedback from the learners.
文摘Writer identity in academic writing has long been ignored by developing L2 writers.Moreover,research has much focused on the reader in shaping writing,and treated the role of the writer as unproblematic.In this essay,the construction of writer identity in developing writers’academic writing practice will be explored through a review of some relevant literature research and gain insights for the development of writer apprentices and writing instruction.
文摘Academic writing is social interaction between writer and reader,during which writers can employ discursive and non-discursive features to construct their identities.However,many student writers who are users of English as an additional language(EAL)may find it challenging to construct their identities in academic writing.Properly constructed identity in academic writing can help EAL student writers develop a stronger sense of self,exercise their agency,and negotiate the academic discourse.Therefore,this paper reviews empirical studies on EAL student writers'identity construction when they write in English to investigate the features of identities that EAL student writers construct in texts and the factors that influence their identity construction.The findings show that,compared with expert writers and native-English-speaking(NES)counterparts,EAL student writers tend to present a weak authorial identity.Furthermore,EAL student writers tend to be more engaged with texts than with readers and lack commitment to their claims.The identities that EAL student writers construct in academic writing are also interwoven with EAL students'English proficiency levels,educational experience,disciplinary conventions,genre affordances,and audience awareness.The findings of this literature review can help teachers and educators raise EAL students’identity awareness and facilitate students in strategically constructing writer identities in academic writing.
文摘Large Language Models(LLMs),exemplified by ChatGPT,have significantly reshaped text generation,particularly in the realm of writing assistance.While ethical considerations underscore the importance of transparently acknowledging LLM use,especially in scientific communication,genuine acknowledgment remains infrequent.A potential avenue to encourage accurate acknowledging of LLM-assisted writing involves employing automated detectors.Our evaluation of four cutting-edge LLM-generated text detectors reveals their suboptimal performance compared to a simple ad-hoc detector designed to identify abrupt writing style changes around the time of LLM proliferation.We contend that the development of specialized detectors exclusively dedicated to LLM-assisted writing detection is necessary.Such detectors could play a crucial role in fostering more authentic recognition of LLM involvement in scientific communication,addressing the current challenges in acknowledgment practices.
文摘Writer/reader(W/R) visibility is regarded as an important indicator of personal involvement. Previous studies concluded that EFL learners tend to contains more personal involvement than native speakers in their writing, making it resemble spoken language as a result. Therefore, this paper examines the degree of W/R visibility in English writing by university-level Chinese learners to verify the applicability of the previous findings on Chinese learners. Based on the data collected in the corpora CLEC,WECCL and LOCNESS, the results show that Chinese EFL learners have the tendency to employ more features of W/R visibility than native speakers, for example the high use of first or second person reference and words that represent mental process. Besides, the paper also reveals little distinction on W/R visibility between English and non-English majors, suggesting the inefficiency of the writing ability of today's English majors.
文摘Revision is a complex,yet important phase in writing to improve the quality of a text.Some revision models are created to explain its components and the ways these components work.However,analysis of available models shows that they are proposed mainly for expert writers,who can complete the complex revision process individually,without the need of support or feedback.Most of the available revision models also do not include audience as a component.Therefore,the purpose of this paper is to introduce an alternative revision model for novice writers at or higher than highschool level with a focus on audience and feedback.First,the definition of revision is made,which is followed by summaries of the importance of audience and feedback in writing.Second,available revision models in literature that serves as the basis of the alternative model are reviewed.Finally,the alternative revision model is introduced with its components and the way these components work is explained.The revision model presented in this paper will contribute to literature on writing by filling the gap in revision models by proposing a model for novice writers and highlighting the importance of audience and feedback.
基金the financial support from the National Natural Science Foundation of China(No.52109119)the Guangxi Natural Science Foundation(No.2021GXNSFBA075030)+2 种基金the Guangxi Science and Technology Project(No.Guike AD20325002)the Chinese Postdoctoral Science Fund Project(No.2022M723408)the Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(China Institute of Water Resources and Hydropower Research)(No.IWHR-SKL-202202)。
文摘The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the mechanical properties and damage/fracture evolution mechanisms of deep rock induced by microdynamic disturbance under three-dimensional stress states are unclear.Therefore,a true triaxial multilevel disturbance test method is proposed,which can completely simulate natural geostress,excavation stress redistribution(such as stress unloading,concentration and rotation),and subsequently the microdynamic disturbance triggering damaged rock failure.Based on a dynamic true triaxial test platform,true triaxial microdynamic disturbance tests under different frequency and amplitudes were carried out on monzogabbro.The results show that increasing amplitude or decreasing frequency diminishes the failure strength of monzogabbro.Deformation modulus gradually decreases during disturbance failure.As frequency and amplitude increase,the degradation rate of deformation modulus decreases slightly,disturbance dissipated energy increases significantly,and disturbance deformation anisotropy strengthens obviously.A damage model has been proposed to quantitatively characterize the disturbance-induced damage evolution at different frequency and amplitude under true triaxial stress.Before disturbance failure,the micro-tensile crack mechanism is dominant,and the micro-shear crack mechanism increases significantly at failure.With the increase of amplitude and frequency,the micro-shear crack mechanism increases.When approaching disturbance failure,the acoustic emission fractal dimension changes from a stable value to local large oscillation,and finally increases sharply to a high value at failure.Finally,the disturbance-induced failure mechanism of surrounding rock in deep engineering is clearly elucidated.
文摘Aspan of twenty-five years,for a company,constitutes a engthy and eventful journey.Twenty-five years ago,a group of oil professionals from the Bureau of Geophysical Prospecting INC (hereinafter referred to as BGP),set foot on the land of Nigeria and embarked on a legendary journey.This is a narrative of resilience,commitment,and heartfelt passion,an inspiring saga that touches the soul.
文摘For all its different forms,democracy is expected to promote people’s well-being,instead of being weaponized to justify hegemony,as democracy is also a principle of global governance.
基金supported by the National Natural Science Foundation of China(Nos.51839009 and 52027814)the Natural Science Foundation of Hubei Province(No.2023AFB589).
文摘High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.
基金This work was supported by Natural Science Foundation of China(Grant No.52278333)the Fundamental Research Funds for the Central Universities(Grant No.N2101021)The work is under the framework of the 111 Project(Grant No.B17009)and Sino-Franco Joint Research Laboratory on Multiphysics and Multiscale Rock Mechanics.
文摘The anisotropic mechanical behavior of rocks under high-stress and high-temperature coupled conditions is crucial for analyzing the stability of surrounding rocks in deep underground engineering.This paper is devoted to studying the anisotropic strength,deformation and failure behavior of gneiss granite from the deep boreholes of a railway tunnel that suffers from high tectonic stress and ground temperature in the eastern tectonic knot in the Tibet Plateau.High-temperature true triaxial compression tests are performed on the samples using a self-developed testing device with five different loading directions and three temperature values that are representative of the geological conditions of the deep underground tunnels in the region.Effect of temperature and loading direction on the strength,elastic modulus,Poisson’s ratio,and failure mode are analyzed.The method for quantitative identification of anisotropic failure is also proposed.The anisotropic mechanical behaviors of the gneiss granite are very sensitive to the changes in loading direction and temperature under true triaxial compression,and the high temperature seems to weaken the inherent anisotropy and stress-induced deformation anisotropy.The strength and deformation show obvious thermal degradation at 200℃due to the weakening of friction between failure surfaces and the transition of the failure pattern in rock grains.In the range of 25℃ 200℃,the failure is mainly governed by the loading direction due to the inherent anisotropy.This study is helpful to the in-depth understanding of the thermal-mechanical behavior of anisotropic rocks in deep underground projects.
文摘China and Malaysia established diplomatic ties fifty years ago.Over the past half-century,the bilateral relationship has made great progress in various fields,delivering tangible benefits to the people of the two countries and making positive contributions to the peace,stability,and prosperity of the region.
基金Project supported by the Natural Science Foundation of Guangdong Province (Grant No.2021A1515012335)the National Natural Science Foundation of China (Grant No.11274400)+2 种基金Pearl River S&T Nova Program of Guangzhou (Grant No.201506010059)State Key Laboratory of High Field Laser Physics (Shanghai Institute of Optics and Fine Mechanics)State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University)。
文摘It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent semiconductors.Nevertheless,in this study,we demonstrate that using high-numerical-aperture 800 nm femtosecond laser direct writing with controlled pulse energy and scanning speed in the near-damage-threshold regime,polarization-dependent deep-subwavelength single grooves with linewidths of~180 nm can be controllably prepared on Si.Generally,the single-groove linewidth increases slightly with increase in the pulse energy and decrease in the scanning speed,whereas the single-groove depth significantly increases from~300 nm to~600 nm with decrease in the scanning speed,or even to over 1μm with multi-processing,indicating the characteristics of transverse clamping and longitudinal growth of such deep-subwavelength single grooves.Energy dispersive spectroscopy composition analysis of the near-groove region confirms that single-groove formation tends to be an ultrafast,non-thermal ablation process,and the oxidized deposits near the grooves are easy to clean up.Furthermore,the results,showing both the strong dependence of groove orientation on laser polarization and the occurrence of double-groove structures due to the interference of pre-formed orthogonal grooves,indicate that the extraordinary field enhancement of strong polarization sensitivity in the deep-subwavelength groove plays an important role in single-groove growth with high stability and collimation.