Quantitative prediction of reservoir properties(e.g., gas saturation, porosity, and shale content) of tight reservoirs is of great significance for resource evaluation and well placements. However, the complex pore st...Quantitative prediction of reservoir properties(e.g., gas saturation, porosity, and shale content) of tight reservoirs is of great significance for resource evaluation and well placements. However, the complex pore structures, poor pore connectivity, and uneven fluid distribution of tight sandstone reservoirs make the correlation between reservoir parameters and elastic properties more complicated and thus pose a major challenge in seismic reservoir characterization. We have developed a partially connected double porosity model to calculate elastic properties by considering the pore structure and connectivity, and to analyze these factors' influences on the elastic behaviors of tight sandstone reservoirs. The modeling results suggest that the bulk modulus is likely to be affected by the pore connectivity coefficient, while the shear modulus is sensitive to the volumetric fraction of stiff pores. By comparing the model predictions with the acoustic measurements of the dry and saturated quartz sandstone samples, the volumetric fraction of stiff pores and the pore connectivity coefficient can be determined. Based on the calibrated model, we have constructed a 3D rock physics template that accounts for the reservoir properties' impacts on the P-wave impedance, S-wave impedance, and density. The template combined with Bayesian inverse theory is used to quantify gas saturation, porosity, clay content, and their corresponding uncertainties from elastic parameters. The application of well-log and seismic data demonstrates that our 3D rock physics template-based probabilistic inversion approach performs well in predicting the spatial distribution of high-quality tight sandstone reservoirs in southwestern China.展开更多
Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to comp...Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.展开更多
This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) ...This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) during storage. The APC values were tested and images of the fish surface were taken when fish were stored at room temperature. Then, images</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">’</span></span></span><span><span><span><span> color-space conversion among RGB, HSV, and L*a*b* color spaces was carried out and analyzed. The results revealed that a* and b* values from the UV-light image decreased linearly during storage. A further regression analysis of these two parameters with APC value demonstrated a good exponential relationship between the a* value and the APC value (R</span><sup><span>2</span></sup><span> = 0.97), followed by the b* (R</span><sup><span>2</span></sup><span> = 0.85). Therefore, our results suggest that the change in color of the fish surface under UV light can be used to assess fish freshness during storage.展开更多
Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainab...Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainable construction of smart first aid. Methods: A total of 105 patients with severe neurological diseases in Zhuji people’s Hospital and cooperative units were selected, and 52 cases in the research group and 53 cases in the control group were divided according to the single and double number visiting time: In this paper, through reading the literature, the development of Internet + wisdom first aid treatment of patients with severe neurological diseases was investigated, and the common problems were analyzed and summarized, and the research group used the PDCA circulation method to sort out the existing problems, analyze the causes of the problems and improve them. The difference in treatment time between the two groups was compared, and the patient’s satisfaction was evaluated for the time of being transferred to the hospital emergency room by 120 ambulances, the time from emergency admission to surgery (Cath lab), and the satisfaction of the patient. Results: The time from emergency treatment to the operation room (catheter room) in the study group was significantly shortened, and patient satisfaction was significantly improved compared with that in the control group, with a statistically significant difference (P Conclusion: Through the application of PDCA circulation method in the Internet + smart emergency treatment of neurologically severe preoperative patients, the Internet + smart emergency mode can be continuously improved, the treatment process can be significantly optimized, the first aid time can be shortened, and the treatment efficiency of neurocritical ill patients can be improved. Therefore, it has been expected to improve the success rate of treatment and improve the success rate of neurological patients.展开更多
Objective: Severe traumatic brain injury (sTBI) is one of the common acute and critical diseases in neurosurgery. So we aim to explore the clinical effectiveness of an intelligent emergency care model in patients with...Objective: Severe traumatic brain injury (sTBI) is one of the common acute and critical diseases in neurosurgery. So we aim to explore the clinical effectiveness of an intelligent emergency care model in patients with severe traumatic brain injury. Methods: Eighty patients with severe traumatic brain injury (sTBI) who were treated in Zhuji People’s Hospital of Zhejiang Province from January 2019 to December 2021 were selected as the study subjects. The patients were divided into an observation group and a control group with 40 patients in each group according to the random number table method. Patients in the control group received conventional first-aid nursing mode intervention, and the intelligent emergency nursing mode was used for the observation group based on the control group. Comparisons were conducted between the two groups on the time of arrival to the emergency room, the time from the emergency room to the operating room, Glasgow Coma Scale (GCS) score before surgery, GCS score when leaving the Intensive Care Unit (ICU), the average length of ICU stay, the average length of hospital stay, the total hospital costs. Results: The time of arrival to the emergency room, the time from the emergency room to the operating room, the average length of ICU stay, the average length of hospital stay, and the total hospital costs in the observation group were significantly lower than those in the control group, and the differences were statistically significant (All P Conclusion: Intelligent emergency nursing mode can shorten the time of sTBI rescue, the length of ICU stay, and the average length of hospital stay, reduce the total hospitalization cost, improve the prognosis, with good efficacy, reduce the total cost of hospitalization, and improve the prognosis with better efficacy.展开更多
The hydrogen evolution reaction(HER) is a half-cell reaction in water electrolysis for producing hydrogen gas. In industrial water electrolysis, the HER is often conducted in alkaline media to achieve higher stability...The hydrogen evolution reaction(HER) is a half-cell reaction in water electrolysis for producing hydrogen gas. In industrial water electrolysis, the HER is often conducted in alkaline media to achieve higher stability of the electrode materials. However, the kinetics of the HER in alkaline medium is slow relative to that in acid because of the low concentration of protons in the former.Under the latter conditions, the entire HER process will require additional effort to obtain protons by water dissociation near or on the catalyst surface. Heterostructured catalysts, with fascinating synergistic effects derived from their heterogeneous interfaces, can provide multiple functional sites for the overall reaction process. At present, the activity of the most active known heterostructured catalysts surpasses(platinum-based heterostructures) or approaches (noble-metal-free heterostructures) that of the commercial Pt/C catalyst under alkaline conditions, demonstrating an infusive potential to break through the bottlenecks. This review summarizes the most representative and recent heterostructured HER catalysts for alkaline medium. The basics and principles of the HER under alkaline conditions are first introduced, followed by a discussion of the latest advances in heterostructured catalysts with/without noblemetal-based heterostructures. Special focus is placed on approaches for enhancing the reaction rate by accelerating the Volmer step. This review aims to provide an overview of the current developments in alkaline HER catalysts, as well as the design principles for the future development of heterostructured nano-or micro-sized electrocatalysts.展开更多
AIM: To investigate the ocular surface microbiome profile of patients with fungal keratitis(FK) through bacterial 16 S r DNA sequencing. METHODS: The swab samples were collected from 8 patients with FK(Group 1 from th...AIM: To investigate the ocular surface microbiome profile of patients with fungal keratitis(FK) through bacterial 16 S r DNA sequencing. METHODS: The swab samples were collected from 8 patients with FK(Group 1 from the corneal ulcer, Group 2 from the conjunctival sac of the infected eyes, and Group 3 from the conjunctival sac of the fellow eyes) and 10 healthy eyes(Group 4 from the conjunctival sac). Bacterial 16 S rDNA V4-V5 region sequencing was performed to characterize the bacterial communities on the ocular surfaces of the patients with FK. RESULTS: Our metagenomic data showed that 97% of the sequence reads were categorized into 245 distinct bacterial genera, with 67.75±7.79 genera detected in Group 1, 73.80±13.44 in Group 2, 74.57±14.14 in Group 3, and 89.60±27.49 in Group 4. Compared with the healthy eyes(Group 4), both infected(Groups 1 and 2) and fellow eyes(Group 3) of the patients with FK showed reduced bacterial diversity and altered ocular surface microbiota compositions, with lower abundance of Corynebacterium and Staphylo coccus and higher abundances of Pseudomonas, Achromobacter, Caulobacter and Psychrobacter. CONCLUSION: Our report depicts the altered ocular surface bacterial community structures both in the affected and fellow eyes of patients with FK. These changes may contribute to the pathogenesis of FK or the increased risk for FK.展开更多
Additive manufacturing(AM)is an emerging customized three-dimensional(3D)functional product fabrication technology.It provides a higher degree of design freedom,reduces manufacturing steps,cost and production cycles.H...Additive manufacturing(AM)is an emerging customized three-dimensional(3D)functional product fabrication technology.It provides a higher degree of design freedom,reduces manufacturing steps,cost and production cycles.However,existing metallic component 3D printing techniques are mainly for the manufacture of single material components.With the increasing commercial applications of AM technologies,the need for 3D printing of more than one type of dissimilar materials in a single component increases.Therefore,investigations on multi-material AM(MMAM)emerge over the past decade.Lasers are currently widely used for the AM of metallic components where high temperatures are involved.Here we report the progress and trend in laser-based macro-and micro-scale AM of multiple metallic components.The methods covered in this paper include laser powder bed fusion,laser powder directed energy deposition,and laser-induced forward transfer for MMAM applications.The principles and process/material characteristics are described.Potential applications and challenges are discussed.Finally,future research directions and prospects are proposed.展开更多
Tungsten(W)and stainless steel(SS)are well known for the high melting point and good corrosion resistance respectively.Bimetallic W-SS structures would offer potential applications in extreme environments.In this stud...Tungsten(W)and stainless steel(SS)are well known for the high melting point and good corrosion resistance respectively.Bimetallic W-SS structures would offer potential applications in extreme environments.In this study,a SS→W→SS sandwich structure is fabricated via a special laser powder bed fusion(LPBF)method based on an ultrasonic-assisted powder deposition mechanism.Material characterization of the SS→W interface and W→SS interface was conducted,including microstructure,element distribution,phase distribution,and nano-hardness.A coupled modelling method,combining computational fluid dynamics modelling with discrete element method,simulated the melt pool dynamics and solidification at the material interfaces.The study shows that the interface bonding of SS→W(SS printed on W)is the combined effect of solid-state diffusion with different elemental diffusion rates and grain boundary diffusion.The keyhole mode of the melt pool at the W→SS(W printed on SS)interface makes the pre-printed SS layers repeatedly remelted,causing the liquid W to flow into the sub-surface of the pre-printed SS through the keyhole cavities realizing the bonding of the W→SS interface.The above interfacial bonding behaviours are significantly different from the previously reported bonding mechanism based on the melt pool convection during multiple material LPBF.The abnormal material interfacial bonding behaviours are reported for the first time.展开更多
Human–machine interactions using deep-learning methods are important in the research of virtual reality,augmented reality,and metaverse.Such research remains challenging as current interactive sensing interfaces for ...Human–machine interactions using deep-learning methods are important in the research of virtual reality,augmented reality,and metaverse.Such research remains challenging as current interactive sensing interfaces for single-point or multipoint touch input are trapped by massive crossover electrodes,signal crosstalk,propagation delay,and demanding configuration requirements.Here,an all-inone multipoint touch sensor(AIOM touch sensor)with only two electrodes is reported.The AIOM touch sensor is efficiently constructed by gradient resistance elements,which can highly adapt to diverse application-dependent configurations.Combined with deep learning method,the AIOM touch sensor can be utilized to recognize,learn,and memorize human–machine interactions.A biometric verification system is built based on the AIOM touch sensor,which achieves a high identification accuracy of over 98%and offers a promising hybrid cyber security against password leaking.Diversiform human–machine interactions,including freely playing piano music and programmatically controlling a drone,demonstrate the high stability,rapid response time,and excellent spatiotemporally dynamic resolution of the AIOM touch sensor,which will promote significant development of interactive sensing interfaces between fingertips and virtual objects.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 52071278, 51827801)the National Key Research and Development Program of China (No. 2018YFA0703603)。
基金supported by the National Natural Science Foundation of China (42104121)the Scientific Research and Technology Development Project of the CNPC (2021DJ0606)。
文摘Quantitative prediction of reservoir properties(e.g., gas saturation, porosity, and shale content) of tight reservoirs is of great significance for resource evaluation and well placements. However, the complex pore structures, poor pore connectivity, and uneven fluid distribution of tight sandstone reservoirs make the correlation between reservoir parameters and elastic properties more complicated and thus pose a major challenge in seismic reservoir characterization. We have developed a partially connected double porosity model to calculate elastic properties by considering the pore structure and connectivity, and to analyze these factors' influences on the elastic behaviors of tight sandstone reservoirs. The modeling results suggest that the bulk modulus is likely to be affected by the pore connectivity coefficient, while the shear modulus is sensitive to the volumetric fraction of stiff pores. By comparing the model predictions with the acoustic measurements of the dry and saturated quartz sandstone samples, the volumetric fraction of stiff pores and the pore connectivity coefficient can be determined. Based on the calibrated model, we have constructed a 3D rock physics template that accounts for the reservoir properties' impacts on the P-wave impedance, S-wave impedance, and density. The template combined with Bayesian inverse theory is used to quantify gas saturation, porosity, clay content, and their corresponding uncertainties from elastic parameters. The application of well-log and seismic data demonstrates that our 3D rock physics template-based probabilistic inversion approach performs well in predicting the spatial distribution of high-quality tight sandstone reservoirs in southwestern China.
基金the financial support from the Natural Science Foundation of China (Nos.52179118,52209151 and 42307238)the Science and Technology Project of Jiangsu Provincial Department of Science and Technology-Carbon Emissions Peak and Carbon Neutrality Science and Technology Innovation Specia Fund Project (No.BK20220025)+3 种基金the Excellent Postdoctoral Program of Jiangsu Province (No.2023ZB602)the China Postdoctora Science Foundation (Nos.2023M733773 and 2023M733772)Xuzhou City Science and Technology Innovation Special Basic Research Plan (KC23045)State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,China University of Mining&Technology (No SKLGDUEK1916)。
文摘Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar power.Therefore,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage processes.This study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock caverns.Gas thermodynamic responses are validated using additional simulations and the field test data.Temperature and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation modes.Hydrogen reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and pressure.Unlike steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing layer.In CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same areas.Our present research can provide references for the selection of energy storage methods.
文摘This study assessed the feasibility of developing a machine vision system equipped with ultraviolet (UV) light, using changes in fish-surface color to predict aerobic plate count (APC, a standard freshness indicator) during storage. The APC values were tested and images of the fish surface were taken when fish were stored at room temperature. Then, images</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">’</span></span></span><span><span><span><span> color-space conversion among RGB, HSV, and L*a*b* color spaces was carried out and analyzed. The results revealed that a* and b* values from the UV-light image decreased linearly during storage. A further regression analysis of these two parameters with APC value demonstrated a good exponential relationship between the a* value and the APC value (R</span><sup><span>2</span></sup><span> = 0.97), followed by the b* (R</span><sup><span>2</span></sup><span> = 0.85). Therefore, our results suggest that the change in color of the fish surface under UV light can be used to assess fish freshness during storage.
文摘Objective: To investigate the application and feasibility of PDCA circulation method in the treatment of patients with severe neurological diseases in Internet + smart first aid, with a view to promoting the sustainable construction of smart first aid. Methods: A total of 105 patients with severe neurological diseases in Zhuji people’s Hospital and cooperative units were selected, and 52 cases in the research group and 53 cases in the control group were divided according to the single and double number visiting time: In this paper, through reading the literature, the development of Internet + wisdom first aid treatment of patients with severe neurological diseases was investigated, and the common problems were analyzed and summarized, and the research group used the PDCA circulation method to sort out the existing problems, analyze the causes of the problems and improve them. The difference in treatment time between the two groups was compared, and the patient’s satisfaction was evaluated for the time of being transferred to the hospital emergency room by 120 ambulances, the time from emergency admission to surgery (Cath lab), and the satisfaction of the patient. Results: The time from emergency treatment to the operation room (catheter room) in the study group was significantly shortened, and patient satisfaction was significantly improved compared with that in the control group, with a statistically significant difference (P Conclusion: Through the application of PDCA circulation method in the Internet + smart emergency treatment of neurologically severe preoperative patients, the Internet + smart emergency mode can be continuously improved, the treatment process can be significantly optimized, the first aid time can be shortened, and the treatment efficiency of neurocritical ill patients can be improved. Therefore, it has been expected to improve the success rate of treatment and improve the success rate of neurological patients.
文摘Objective: Severe traumatic brain injury (sTBI) is one of the common acute and critical diseases in neurosurgery. So we aim to explore the clinical effectiveness of an intelligent emergency care model in patients with severe traumatic brain injury. Methods: Eighty patients with severe traumatic brain injury (sTBI) who were treated in Zhuji People’s Hospital of Zhejiang Province from January 2019 to December 2021 were selected as the study subjects. The patients were divided into an observation group and a control group with 40 patients in each group according to the random number table method. Patients in the control group received conventional first-aid nursing mode intervention, and the intelligent emergency nursing mode was used for the observation group based on the control group. Comparisons were conducted between the two groups on the time of arrival to the emergency room, the time from the emergency room to the operating room, Glasgow Coma Scale (GCS) score before surgery, GCS score when leaving the Intensive Care Unit (ICU), the average length of ICU stay, the average length of hospital stay, the total hospital costs. Results: The time of arrival to the emergency room, the time from the emergency room to the operating room, the average length of ICU stay, the average length of hospital stay, and the total hospital costs in the observation group were significantly lower than those in the control group, and the differences were statistically significant (All P Conclusion: Intelligent emergency nursing mode can shorten the time of sTBI rescue, the length of ICU stay, and the average length of hospital stay, reduce the total hospitalization cost, improve the prognosis, with good efficacy, reduce the total cost of hospitalization, and improve the prognosis with better efficacy.
基金financial support provided by National Natural Science Foundation of China (Nos.61301026 and 51802073)the supports from the Talent Introduction Foundation (No.ZRC2014448)+1 种基金the Key Discipline Foundation (No.AKZDXK2015A01) of Anhui Science and Technology Universitythe financial support by the Singapore National Research Foundation under its Campus for Research Excellence And Technological Enterprise (CREATE) program through the Cambridge Center for Carbon Reduction in Chemical Technology (C4T) and eCO2EP programs
文摘The hydrogen evolution reaction(HER) is a half-cell reaction in water electrolysis for producing hydrogen gas. In industrial water electrolysis, the HER is often conducted in alkaline media to achieve higher stability of the electrode materials. However, the kinetics of the HER in alkaline medium is slow relative to that in acid because of the low concentration of protons in the former.Under the latter conditions, the entire HER process will require additional effort to obtain protons by water dissociation near or on the catalyst surface. Heterostructured catalysts, with fascinating synergistic effects derived from their heterogeneous interfaces, can provide multiple functional sites for the overall reaction process. At present, the activity of the most active known heterostructured catalysts surpasses(platinum-based heterostructures) or approaches (noble-metal-free heterostructures) that of the commercial Pt/C catalyst under alkaline conditions, demonstrating an infusive potential to break through the bottlenecks. This review summarizes the most representative and recent heterostructured HER catalysts for alkaline medium. The basics and principles of the HER under alkaline conditions are first introduced, followed by a discussion of the latest advances in heterostructured catalysts with/without noblemetal-based heterostructures. Special focus is placed on approaches for enhancing the reaction rate by accelerating the Volmer step. This review aims to provide an overview of the current developments in alkaline HER catalysts, as well as the design principles for the future development of heterostructured nano-or micro-sized electrocatalysts.
基金Supported by the National Natural Science Foundation of China(No.81670839)the Key Research and Development Plan of Shandong Province(No.2018CXGC1205)
文摘AIM: To investigate the ocular surface microbiome profile of patients with fungal keratitis(FK) through bacterial 16 S r DNA sequencing. METHODS: The swab samples were collected from 8 patients with FK(Group 1 from the corneal ulcer, Group 2 from the conjunctival sac of the infected eyes, and Group 3 from the conjunctival sac of the fellow eyes) and 10 healthy eyes(Group 4 from the conjunctival sac). Bacterial 16 S rDNA V4-V5 region sequencing was performed to characterize the bacterial communities on the ocular surfaces of the patients with FK. RESULTS: Our metagenomic data showed that 97% of the sequence reads were categorized into 245 distinct bacterial genera, with 67.75±7.79 genera detected in Group 1, 73.80±13.44 in Group 2, 74.57±14.14 in Group 3, and 89.60±27.49 in Group 4. Compared with the healthy eyes(Group 4), both infected(Groups 1 and 2) and fellow eyes(Group 3) of the patients with FK showed reduced bacterial diversity and altered ocular surface microbiota compositions, with lower abundance of Corynebacterium and Staphylo coccus and higher abundances of Pseudomonas, Achromobacter, Caulobacter and Psychrobacter. CONCLUSION: Our report depicts the altered ocular surface bacterial community structures both in the affected and fellow eyes of patients with FK. These changes may contribute to the pathogenesis of FK or the increased risk for FK.
文摘Additive manufacturing(AM)is an emerging customized three-dimensional(3D)functional product fabrication technology.It provides a higher degree of design freedom,reduces manufacturing steps,cost and production cycles.However,existing metallic component 3D printing techniques are mainly for the manufacture of single material components.With the increasing commercial applications of AM technologies,the need for 3D printing of more than one type of dissimilar materials in a single component increases.Therefore,investigations on multi-material AM(MMAM)emerge over the past decade.Lasers are currently widely used for the AM of metallic components where high temperatures are involved.Here we report the progress and trend in laser-based macro-and micro-scale AM of multiple metallic components.The methods covered in this paper include laser powder bed fusion,laser powder directed energy deposition,and laser-induced forward transfer for MMAM applications.The principles and process/material characteristics are described.Potential applications and challenges are discussed.Finally,future research directions and prospects are proposed.
基金funded by the Engineering and Physical Science Research Council(EPSRC),UK(Grant Nos.EP/P027563/1 and EP/M028267/1)the Science and Technology Facilities Council(STFC)(Grant No.ST/R006105/1)the Bridging for Innovators Programme of Department for Business,Energy and Industrial Strategy(BEIS),UK.
文摘Tungsten(W)and stainless steel(SS)are well known for the high melting point and good corrosion resistance respectively.Bimetallic W-SS structures would offer potential applications in extreme environments.In this study,a SS→W→SS sandwich structure is fabricated via a special laser powder bed fusion(LPBF)method based on an ultrasonic-assisted powder deposition mechanism.Material characterization of the SS→W interface and W→SS interface was conducted,including microstructure,element distribution,phase distribution,and nano-hardness.A coupled modelling method,combining computational fluid dynamics modelling with discrete element method,simulated the melt pool dynamics and solidification at the material interfaces.The study shows that the interface bonding of SS→W(SS printed on W)is the combined effect of solid-state diffusion with different elemental diffusion rates and grain boundary diffusion.The keyhole mode of the melt pool at the W→SS(W printed on SS)interface makes the pre-printed SS layers repeatedly remelted,causing the liquid W to flow into the sub-surface of the pre-printed SS through the keyhole cavities realizing the bonding of the W→SS interface.The above interfacial bonding behaviours are significantly different from the previously reported bonding mechanism based on the melt pool convection during multiple material LPBF.The abnormal material interfacial bonding behaviours are reported for the first time.
基金supported by National Natural Science Foundation of China under Grants (U1805261 and 22161142024)A~*STAR SERC AME Programmatic Fund (A18A7b0058)
文摘Human–machine interactions using deep-learning methods are important in the research of virtual reality,augmented reality,and metaverse.Such research remains challenging as current interactive sensing interfaces for single-point or multipoint touch input are trapped by massive crossover electrodes,signal crosstalk,propagation delay,and demanding configuration requirements.Here,an all-inone multipoint touch sensor(AIOM touch sensor)with only two electrodes is reported.The AIOM touch sensor is efficiently constructed by gradient resistance elements,which can highly adapt to diverse application-dependent configurations.Combined with deep learning method,the AIOM touch sensor can be utilized to recognize,learn,and memorize human–machine interactions.A biometric verification system is built based on the AIOM touch sensor,which achieves a high identification accuracy of over 98%and offers a promising hybrid cyber security against password leaking.Diversiform human–machine interactions,including freely playing piano music and programmatically controlling a drone,demonstrate the high stability,rapid response time,and excellent spatiotemporally dynamic resolution of the AIOM touch sensor,which will promote significant development of interactive sensing interfaces between fingertips and virtual objects.
