Strength-ductility trade-off is a common issue in Mg alloys. This work proposed that a synergistic enhancement of strength and ductility could be achieved through tuning interlayer dwell time(IDT) in the wire and arc ...Strength-ductility trade-off is a common issue in Mg alloys. This work proposed that a synergistic enhancement of strength and ductility could be achieved through tuning interlayer dwell time(IDT) in the wire and arc additive manufacturing(WAAM) process of Mg alloy.The thermal couples were used to monitor the thermal history during the WAAM process. Additionally, the effect of different IDTs on the microstructure characteristics and resultant mechanical properties of WAAM-processed Mg alloy thin-wall were investigated. The results showed that the stable temperature of the thin-wall component could reach 290 ℃ at IDT=0s, indicating that the thermal accumulation effect was remarkable. Consequently, unimodal coarse grains with an average size of 39.6 μm were generated, and the resultant room-temperature tensile property was poor. With the IDT extended to 60s, the thermal input and thermal dissipation reached a balance, and the stable temperature was only 170 ℃, closing to the initial temperature of the substrate. A refined grain structure with bimodal size distribution was obtained. The remelting zone had fine grains with the size of 15.2 μm, while the arc zone owned coarse grains with the size of 24.5 μm.The alternatively distributed coarse and fine grains lead to the elimination of strength-ductility trade-off. The ultimate tensile strength and elongation of the samples at IDT=60s are increased by 20.6 and 75.0% of those samples at IDT=0s, respectively. The findings will facilitate the development of additive manufacturing processes for advanced Mg alloys.展开更多
Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading...Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy.Here,the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities.Compared to the coarse-grain and heterogeneous-grain structured alloys,the GHG structured one exhibits dramatical enhancement in strength,ductility,and strain hardening capability.To the best of our knowledge,its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility.These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects.In summary,our study provides a feasible way to develop new Mg alloys with high strength and good ductility.展开更多
BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradua...BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradually regained consciousness after surgery.HBOT was administered 22 d after surgery due to speech impairment.Paradoxical herniation appeared on the second day after treatment,and the patient’s condition worsened after receiving mannitol treatment at the rehabilitation hospital.After timely skull repair,the paradoxical herniation was resolved,and the patient regained consciousness and had a good recovery as observed at the follow-up visit.CONCLUSION Paradoxical herniation is rare and may be caused by HBOT.However,the underlying mechanism is unknown,and the understanding of this phenomenon is insufficient.The use of mannitol may worsen this condition.Timely skull repair can treat paradoxical herniation and prevent serious complications.展开更多
In the realm of Artificial Intelligence (AI), there exists a complex landscape where promises of efficiency and innovation clash with unforeseen disruptions across Information Technology (IT) and broader societal real...In the realm of Artificial Intelligence (AI), there exists a complex landscape where promises of efficiency and innovation clash with unforeseen disruptions across Information Technology (IT) and broader societal realms. This paper sets out on a journey to explore the intricate paradoxes inherent in AI, focusing on the unintended consequences that ripple through IT and beyond. Through a thorough examination of literature and analysis of related works, this study aims to shed light on the complexities surrounding the AI paradox. It delves into how this paradox appears in various domains, such as algorithmic biases, job displacement, ethical dilemmas, and privacy concerns. By mapping out these unintended disruptions, this research seeks to offer a nuanced understanding of the challenges brought forth by AI-driven transformations. Ultimately, its goal is to pave the way for the responsible development and deployment of AI, fostering a harmonious integration of technological progress with societal values and priorities.展开更多
Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used ...Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used to partially explain this paradox, while introducing new problems. Hereby, we propose a better theory, named Sun Matters Theory, to explain this paradox. Moreover, this unique theory supports and extended the Einstein’s static universe model proposed by Albert Einstein in 1917. Further, we proposed our new universe model, “Sun Model of Universe”. Based on the new model and novel theory, we generated innovative field equation by upgrading Einstein’s Field Equation through adding back the cosmological constant, introducing a new variable and modifying the gravitationally-related concepts. According to the Sun Model of Universe, the dark matter and dark energy comprise the so-called “Sun Matters”. The observed phenomenon like the red shift is explained as due to the interaction of ordinary light with Sun Matters leading to its energy and frequency decrease. In Sun Model, our big universe consists of many universes with ordinary matter at the core mixed and surrounded with the Sun Matters. In those universes, the laws of physics may be completely or partially different from that of our ordinary universe with parallel civilizations. The darkness of night can be easily explained as resulting from the interaction of light with the Sun Matters leading to the sharp decrease in the light intensity. Sun Matters also scatter the light from a star, which makes it shining as observed by Hubble. Further, there is a kind of Sun Matters named “Sun Waters”, surrounding every starts. When lights pass by the sun, the Sun Waters deflect the lights to bend the light path. According to the Sun Model, it is the light bent not the space bent that was proposed in the theory of relativities.展开更多
BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent for...BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent foramen ovale(PFO).CASE SUMMARY Here,we report a case of simultaneous coronary and lower limb artery embolism in a PFO patient carrier of a CVC.The patient presented to the hospital with acute chest pain and lower limb fatigue.Doppler ultrasound showed a large thrombus in the right internal jugular vein,precisely at the tip of the CVC.Transthoracic and transesophageal echocardiography confirmed the existence of a PFO,with inducible right-to-left shunting by the Valsalva maneuver.The patient was administered an extended course of anticoagulation therapy,and then the CVC was successfully removed.Percutaneous PFO closure was not undertaken.There was no recurrence during follow-up.CONCLUSION Thus,CVC-associated thrombosis is a potential source for multiple PDE in PFO patients.展开更多
The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality para...The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality paradox is also evident when comparing Nigeria,a heavily populated,poorly vaccinated and weakly mandated country to Israel,a small,highly vaccinated and strictly mandated country.Nigeria has almost 4 times lower COVID mortality than Israel.In this Field of Vision perspective,I explain how this paradox has evolved drawing upon my academic,clinical and social experience.Since April 2020,I’ve developed and been using the Egyptian immune-modulatory Kelleni’s protocol to manage COVID-19 patients including pediatric,geriatric,pregnant,immune-compromised and other individuals suffering from multiple comorbidities.It’s unfortunate that severe acute respiratory syndrome coronavirus 2 is still evolving accompanied by more deaths.However in Africa,we’ve been able to live without anxiety or mandates throughout the pandemic because we trust science and adopted early treatment using safe,and effective repurposed drugs that have saved the majority of COVID-19 patients.This article represents an African and Egyptian tale of honor.展开更多
Professors Mohazzbi and Luo [1] published “Despite several attempts have been made to explain the twin paradox … none of the explanations … resolved the paradox. If the paradox can be ever resolved, it requires a m...Professors Mohazzbi and Luo [1] published “Despite several attempts have been made to explain the twin paradox … none of the explanations … resolved the paradox. If the paradox can be ever resolved, it requires a much deeper understanding … of the theory of relativity”. The deeper understanding of resolving the paradox is by applying more explicit definitions of proper time interval, Lorentz transform, time dilation, and aging time.展开更多
Developing low-cost rolled Mg alloys with both high strength and ductility is desirable,while the improved strength is generally accompanied with decreased ductility.Here,by using rotated hard-plate rolling(RHPR)with ...Developing low-cost rolled Mg alloys with both high strength and ductility is desirable,while the improved strength is generally accompanied with decreased ductility.Here,by using rotated hard-plate rolling(RHPR)with a total thickness reduction of~85%,we obtained a Mg-8Al-0.5Zn-0.8Ce(wt.%,AZ80-0.8Ce)alloy with a high strength-ductility synergy,i.e.,the yield strength(YS),ultimate tensile strength(UTS)and elongation-to-failure(EF)are~308 MPa,~360 MPa and~13.8%,respectively.It reveals that the high YS is mainly originated from grain boundary strengthening(~212 MPa),followed by dislocation strengthening(~43 MPa)and precipitation hardening(~25 MPa).It is found that a relatively homogeneous fine grain structure containing a large fraction(~62%)of low angle boundaries(LABs)is achieved in the RHPRed alloy,which is benefit for the high tensile EF value.It demonstrates that LABs have important contributions to strengthening and homogenizing tensile deformation process,leading to the simultaneous high strength and high EF.Our work provides a new insight for fabrication of low-cost high performance Mg alloys with an excellent strength-ductility synergy.展开更多
Different from the common delayed synchronization(DS)in which response appears after stimulation,anticipated synchronization(AS)in unidirectionally coupled neurons denotes a counterintuitive phenomenon in which respon...Different from the common delayed synchronization(DS)in which response appears after stimulation,anticipated synchronization(AS)in unidirectionally coupled neurons denotes a counterintuitive phenomenon in which response of the receiver neuron appears before stimulation of the sender neuron,showing an interesting function of brain to anticipate the future.The dynamical mechanism for the AS remains unclear due to complex dynamics of inhibitory and excitatory modulations.In this article,the paradoxical roles of excitatory synapse and inhibitory autapse in the formation of AS are acquired.Firstly,in addition to the common roles such that inhibitory modulation delays and excitatory modulation advances spike,paradoxical roles of excitatory stimulation to delay spike via type-II phase response and of inhibitory autapse to advance spike are obtained in suitable parameter regions,extending the dynamics and functions of the excitatory and inhibitory modulations.Secondly,AS is related to the paradoxical roles of the excitatory and inhibitory modulations,presenting deep understandings to the AS.Inhibitory autapse induces spike of the receiver neuron advanced to appear before that of the sender neuron at first,and then excitatory synapse plays a delay role to prevent the spike further advanced,resulting in the AS as the advance and delay effects realize a dynamic balance.Lastly,inhibitory autapse with strong advance,middle advance,and weak advance and delay effects induce phase drift(spike of the receiver neuron advances continuously),AS,and DS,respectively,presenting comprehensive relationships between AS and other behaviors.The results present potential measures to modulate AS related to brain function.展开更多
BACKGROUND Functional vocal cord disorders can be a differential diagnosis for postoperative upper airway obstruction requiring urgent intervention.However,this may be unfamiliar to anesthesiologists who would favor i...BACKGROUND Functional vocal cord disorders can be a differential diagnosis for postoperative upper airway obstruction requiring urgent intervention.However,this may be unfamiliar to anesthesiologists who would favor inappropriate airway intervention and increased morbidity.CASE SUMMARY A 61-year-old woman underwent cervical laminectomy,followed by laparoscopic cholecystectomy 10 mo later.Despite adequate reversal of neuromuscular blockade,the patient experienced repetitive respiratory difficulty with inspiratory stridor after extubation.After the second operation,the patient was diagnosed with paradoxical vocal fold motion(PVFM)by an otolaryngologist based on the clinical features and fiberoptic bronchoscopy results,and the patient was successfully treated.CONCLUSION PVFM should be considered a differential diagnosis if a patient presents with stridor after general anesthesia.展开更多
In renewal theory, the Inspection Paradox refers to the fact that an interarrival period in a renewal process which contains a fixed inspection time tends to be longer than one for the corresponding uninspected proces...In renewal theory, the Inspection Paradox refers to the fact that an interarrival period in a renewal process which contains a fixed inspection time tends to be longer than one for the corresponding uninspected process. We focus on the paradox for Bernoulli trials. Probability distributions and moments for the lengths of the interarrival periods are derived for the inspected process, and we compare them to those for the uninspected case.展开更多
The Inspection Paradox refers to the fact that in a Renewal Process, the length of the interarrival period which contains a fixed time is stochastically larger than the length of a typical interarrival period. To prov...The Inspection Paradox refers to the fact that in a Renewal Process, the length of the interarrival period which contains a fixed time is stochastically larger than the length of a typical interarrival period. To provide a more complete understanding of this phenomenon, conditioning arguments are used to obtain the distributions and moments of the lengths of the interarrival periods other than the one containing this fixed time for the case of the time-homogeneous Poisson Process. Distributions of the waiting times for events that occur both before and after this fixed time are derived. This provides a fairly complete probabilistic analysis of the Inspection Paradox.展开更多
It has been 50 years since Hawking described the black hole (BH) information paradox. The combination of BH radiation and subsequent BH evaporation was found to take trapped information into oblivion contrary to the l...It has been 50 years since Hawking described the black hole (BH) information paradox. The combination of BH radiation and subsequent BH evaporation was found to take trapped information into oblivion contrary to the law of conservation of quantum information. Numerous attempts have been made since to resolve this paradox. A brief review herein documents how all these attempts have significant shortcomings, meaning the paradox is still unresolved. A relatively new cosmological theory offers a resolution despite not being developed for that purpose. The theory, entitled the probabilistic spacetime theory (PST), starts with an alteration in one basic assumption compared to all current cosmological theories. Spacetime, instead of being seen as a void or container of other entities, is viewed as the most fundamental entity in the universe, composed of energy fragments, and (in keeping with the conservation principle) impermeable to destruction. The potential contribution of the PST in resolving the information paradox is delineated, with the finding that the single change in the conceptualization of spacetime results in the disappearance of the paradox and not information.展开更多
Relying on euthanasia’s definitionally derived set of propositions to provide its purpose,claims,and benefit,we obtain the core concept.Nonetheless,given its core concept,euthanasia is demonstrated to provide no bene...Relying on euthanasia’s definitionally derived set of propositions to provide its purpose,claims,and benefit,we obtain the core concept.Nonetheless,given its core concept,euthanasia is demonstrated to provide no benefit to the animal to justify its use.Euthanasia 1)cannot possibly,and therefore does not,end unbearable suffering,2)it fails to hasten death,and 3)it,therefore,provides no perceptible relief to the patient.These findings are significant because the argument’s validity does not permit euthanasia to satisfy its definitionally derived purpose,claims,or benefit on logical grounds.In other words,the argument is that as a form of legalized assisted suicide,euthanasia is wrong but not in the way principled arguments would suggest.Additionally,irrespective of euthanasia actually doing what it claims,if it is allowed to be provisioned,then euthanasia will affect vulnerable populations exactly like nonprincipled arguments claim.Therefore,despite sharing aspects with each type of argument in the extant literature,my argument against euthanasia can be categorized as neither principled nor nonprincipled,which makes it significant because it may be the first of a new category of argument against the concept and practice to enter the discourse on euthanasia.As a corollary,since we prove that unbearable suffering logically entails death,when it is authentic signifying that death is imminent,because euthanasia’s only purpose is to end unbearable suffering by inducing death,euthanasia is completely obviated.展开更多
基金the support from Projects of Major Innovation Platforms for Scientific and Technological and Local Transformation of Scientific and Technological Achievements of Xi’an (No.20GXSF0003)the Higher Education Institution Discipline Innovation and Intelligence Base of Shaanxi Provincial (No.S2021-ZC-GXYZ0011)National Natural Science Foundation of China (Grants No.51801154)。
文摘Strength-ductility trade-off is a common issue in Mg alloys. This work proposed that a synergistic enhancement of strength and ductility could be achieved through tuning interlayer dwell time(IDT) in the wire and arc additive manufacturing(WAAM) process of Mg alloy.The thermal couples were used to monitor the thermal history during the WAAM process. Additionally, the effect of different IDTs on the microstructure characteristics and resultant mechanical properties of WAAM-processed Mg alloy thin-wall were investigated. The results showed that the stable temperature of the thin-wall component could reach 290 ℃ at IDT=0s, indicating that the thermal accumulation effect was remarkable. Consequently, unimodal coarse grains with an average size of 39.6 μm were generated, and the resultant room-temperature tensile property was poor. With the IDT extended to 60s, the thermal input and thermal dissipation reached a balance, and the stable temperature was only 170 ℃, closing to the initial temperature of the substrate. A refined grain structure with bimodal size distribution was obtained. The remelting zone had fine grains with the size of 15.2 μm, while the arc zone owned coarse grains with the size of 24.5 μm.The alternatively distributed coarse and fine grains lead to the elimination of strength-ductility trade-off. The ultimate tensile strength and elongation of the samples at IDT=60s are increased by 20.6 and 75.0% of those samples at IDT=0s, respectively. The findings will facilitate the development of additive manufacturing processes for advanced Mg alloys.
基金the financial support of the National Natural Science Foundation of China(Grant No.51971088,No.U1910212)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy.Here,the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities.Compared to the coarse-grain and heterogeneous-grain structured alloys,the GHG structured one exhibits dramatical enhancement in strength,ductility,and strain hardening capability.To the best of our knowledge,its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility.These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects.In summary,our study provides a feasible way to develop new Mg alloys with high strength and good ductility.
文摘BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradually regained consciousness after surgery.HBOT was administered 22 d after surgery due to speech impairment.Paradoxical herniation appeared on the second day after treatment,and the patient’s condition worsened after receiving mannitol treatment at the rehabilitation hospital.After timely skull repair,the paradoxical herniation was resolved,and the patient regained consciousness and had a good recovery as observed at the follow-up visit.CONCLUSION Paradoxical herniation is rare and may be caused by HBOT.However,the underlying mechanism is unknown,and the understanding of this phenomenon is insufficient.The use of mannitol may worsen this condition.Timely skull repair can treat paradoxical herniation and prevent serious complications.
文摘In the realm of Artificial Intelligence (AI), there exists a complex landscape where promises of efficiency and innovation clash with unforeseen disruptions across Information Technology (IT) and broader societal realms. This paper sets out on a journey to explore the intricate paradoxes inherent in AI, focusing on the unintended consequences that ripple through IT and beyond. Through a thorough examination of literature and analysis of related works, this study aims to shed light on the complexities surrounding the AI paradox. It delves into how this paradox appears in various domains, such as algorithmic biases, job displacement, ethical dilemmas, and privacy concerns. By mapping out these unintended disruptions, this research seeks to offer a nuanced understanding of the challenges brought forth by AI-driven transformations. Ultimately, its goal is to pave the way for the responsible development and deployment of AI, fostering a harmonious integration of technological progress with societal values and priorities.
文摘Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used to partially explain this paradox, while introducing new problems. Hereby, we propose a better theory, named Sun Matters Theory, to explain this paradox. Moreover, this unique theory supports and extended the Einstein’s static universe model proposed by Albert Einstein in 1917. Further, we proposed our new universe model, “Sun Model of Universe”. Based on the new model and novel theory, we generated innovative field equation by upgrading Einstein’s Field Equation through adding back the cosmological constant, introducing a new variable and modifying the gravitationally-related concepts. According to the Sun Model of Universe, the dark matter and dark energy comprise the so-called “Sun Matters”. The observed phenomenon like the red shift is explained as due to the interaction of ordinary light with Sun Matters leading to its energy and frequency decrease. In Sun Model, our big universe consists of many universes with ordinary matter at the core mixed and surrounded with the Sun Matters. In those universes, the laws of physics may be completely or partially different from that of our ordinary universe with parallel civilizations. The darkness of night can be easily explained as resulting from the interaction of light with the Sun Matters leading to the sharp decrease in the light intensity. Sun Matters also scatter the light from a star, which makes it shining as observed by Hubble. Further, there is a kind of Sun Matters named “Sun Waters”, surrounding every starts. When lights pass by the sun, the Sun Waters deflect the lights to bend the light path. According to the Sun Model, it is the light bent not the space bent that was proposed in the theory of relativities.
基金Supported by Natural Science Foundation of Guangdong Province,No.2021A1515011267and Guangzhou Municipal Science and Technology Bureau,No.2023A03J0984.
文摘BACKGROUND To date,this is the first case of a paradoxical embolism(PDE)that concurrently manifested in the coronary and lower limb arteries and was secondary to a central venous catheter(CVC)thrombus via a patent foramen ovale(PFO).CASE SUMMARY Here,we report a case of simultaneous coronary and lower limb artery embolism in a PFO patient carrier of a CVC.The patient presented to the hospital with acute chest pain and lower limb fatigue.Doppler ultrasound showed a large thrombus in the right internal jugular vein,precisely at the tip of the CVC.Transthoracic and transesophageal echocardiography confirmed the existence of a PFO,with inducible right-to-left shunting by the Valsalva maneuver.The patient was administered an extended course of anticoagulation therapy,and then the CVC was successfully removed.Percutaneous PFO closure was not undertaken.There was no recurrence during follow-up.CONCLUSION Thus,CVC-associated thrombosis is a potential source for multiple PDE in PFO patients.
文摘The coronavirus disease 2019(COVID-19)mortality rate in 55 African countries is almost 4.5 times lower than in the coronavirus disease 2019(COVID-19)despite Africa having over 4.2 times more people.This mortality paradox is also evident when comparing Nigeria,a heavily populated,poorly vaccinated and weakly mandated country to Israel,a small,highly vaccinated and strictly mandated country.Nigeria has almost 4 times lower COVID mortality than Israel.In this Field of Vision perspective,I explain how this paradox has evolved drawing upon my academic,clinical and social experience.Since April 2020,I’ve developed and been using the Egyptian immune-modulatory Kelleni’s protocol to manage COVID-19 patients including pediatric,geriatric,pregnant,immune-compromised and other individuals suffering from multiple comorbidities.It’s unfortunate that severe acute respiratory syndrome coronavirus 2 is still evolving accompanied by more deaths.However in Africa,we’ve been able to live without anxiety or mandates throughout the pandemic because we trust science and adopted early treatment using safe,and effective repurposed drugs that have saved the majority of COVID-19 patients.This article represents an African and Egyptian tale of honor.
文摘Professors Mohazzbi and Luo [1] published “Despite several attempts have been made to explain the twin paradox … none of the explanations … resolved the paradox. If the paradox can be ever resolved, it requires a much deeper understanding … of the theory of relativity”. The deeper understanding of resolving the paradox is by applying more explicit definitions of proper time interval, Lorentz transform, time dilation, and aging time.
基金primarily supported by The Natural Science Foundation of China under Grant Nos.51922048,51871108 and 52001133the Fundamental Research Funds for the Central Universities,JLU,Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)The Science and Technology Development Program of Jilin Province(Nos.20200201193JC and 20210201115GX)。
文摘Developing low-cost rolled Mg alloys with both high strength and ductility is desirable,while the improved strength is generally accompanied with decreased ductility.Here,by using rotated hard-plate rolling(RHPR)with a total thickness reduction of~85%,we obtained a Mg-8Al-0.5Zn-0.8Ce(wt.%,AZ80-0.8Ce)alloy with a high strength-ductility synergy,i.e.,the yield strength(YS),ultimate tensile strength(UTS)and elongation-to-failure(EF)are~308 MPa,~360 MPa and~13.8%,respectively.It reveals that the high YS is mainly originated from grain boundary strengthening(~212 MPa),followed by dislocation strengthening(~43 MPa)and precipitation hardening(~25 MPa).It is found that a relatively homogeneous fine grain structure containing a large fraction(~62%)of low angle boundaries(LABs)is achieved in the RHPRed alloy,which is benefit for the high tensile EF value.It demonstrates that LABs have important contributions to strengthening and homogenizing tensile deformation process,leading to the simultaneous high strength and high EF.Our work provides a new insight for fabrication of low-cost high performance Mg alloys with an excellent strength-ductility synergy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12072236,12162002,and11802086)the Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(Grant No.NJYT-20-A09)the Program for Excellent Young Talents in Colleges and Universities of Anhui Province of China(Grant No.gxyq ZD2020077)。
文摘Different from the common delayed synchronization(DS)in which response appears after stimulation,anticipated synchronization(AS)in unidirectionally coupled neurons denotes a counterintuitive phenomenon in which response of the receiver neuron appears before stimulation of the sender neuron,showing an interesting function of brain to anticipate the future.The dynamical mechanism for the AS remains unclear due to complex dynamics of inhibitory and excitatory modulations.In this article,the paradoxical roles of excitatory synapse and inhibitory autapse in the formation of AS are acquired.Firstly,in addition to the common roles such that inhibitory modulation delays and excitatory modulation advances spike,paradoxical roles of excitatory stimulation to delay spike via type-II phase response and of inhibitory autapse to advance spike are obtained in suitable parameter regions,extending the dynamics and functions of the excitatory and inhibitory modulations.Secondly,AS is related to the paradoxical roles of the excitatory and inhibitory modulations,presenting deep understandings to the AS.Inhibitory autapse induces spike of the receiver neuron advanced to appear before that of the sender neuron at first,and then excitatory synapse plays a delay role to prevent the spike further advanced,resulting in the AS as the advance and delay effects realize a dynamic balance.Lastly,inhibitory autapse with strong advance,middle advance,and weak advance and delay effects induce phase drift(spike of the receiver neuron advances continuously),AS,and DS,respectively,presenting comprehensive relationships between AS and other behaviors.The results present potential measures to modulate AS related to brain function.
文摘BACKGROUND Functional vocal cord disorders can be a differential diagnosis for postoperative upper airway obstruction requiring urgent intervention.However,this may be unfamiliar to anesthesiologists who would favor inappropriate airway intervention and increased morbidity.CASE SUMMARY A 61-year-old woman underwent cervical laminectomy,followed by laparoscopic cholecystectomy 10 mo later.Despite adequate reversal of neuromuscular blockade,the patient experienced repetitive respiratory difficulty with inspiratory stridor after extubation.After the second operation,the patient was diagnosed with paradoxical vocal fold motion(PVFM)by an otolaryngologist based on the clinical features and fiberoptic bronchoscopy results,and the patient was successfully treated.CONCLUSION PVFM should be considered a differential diagnosis if a patient presents with stridor after general anesthesia.
文摘In renewal theory, the Inspection Paradox refers to the fact that an interarrival period in a renewal process which contains a fixed inspection time tends to be longer than one for the corresponding uninspected process. We focus on the paradox for Bernoulli trials. Probability distributions and moments for the lengths of the interarrival periods are derived for the inspected process, and we compare them to those for the uninspected case.
文摘The Inspection Paradox refers to the fact that in a Renewal Process, the length of the interarrival period which contains a fixed time is stochastically larger than the length of a typical interarrival period. To provide a more complete understanding of this phenomenon, conditioning arguments are used to obtain the distributions and moments of the lengths of the interarrival periods other than the one containing this fixed time for the case of the time-homogeneous Poisson Process. Distributions of the waiting times for events that occur both before and after this fixed time are derived. This provides a fairly complete probabilistic analysis of the Inspection Paradox.
文摘It has been 50 years since Hawking described the black hole (BH) information paradox. The combination of BH radiation and subsequent BH evaporation was found to take trapped information into oblivion contrary to the law of conservation of quantum information. Numerous attempts have been made since to resolve this paradox. A brief review herein documents how all these attempts have significant shortcomings, meaning the paradox is still unresolved. A relatively new cosmological theory offers a resolution despite not being developed for that purpose. The theory, entitled the probabilistic spacetime theory (PST), starts with an alteration in one basic assumption compared to all current cosmological theories. Spacetime, instead of being seen as a void or container of other entities, is viewed as the most fundamental entity in the universe, composed of energy fragments, and (in keeping with the conservation principle) impermeable to destruction. The potential contribution of the PST in resolving the information paradox is delineated, with the finding that the single change in the conceptualization of spacetime results in the disappearance of the paradox and not information.
文摘Relying on euthanasia’s definitionally derived set of propositions to provide its purpose,claims,and benefit,we obtain the core concept.Nonetheless,given its core concept,euthanasia is demonstrated to provide no benefit to the animal to justify its use.Euthanasia 1)cannot possibly,and therefore does not,end unbearable suffering,2)it fails to hasten death,and 3)it,therefore,provides no perceptible relief to the patient.These findings are significant because the argument’s validity does not permit euthanasia to satisfy its definitionally derived purpose,claims,or benefit on logical grounds.In other words,the argument is that as a form of legalized assisted suicide,euthanasia is wrong but not in the way principled arguments would suggest.Additionally,irrespective of euthanasia actually doing what it claims,if it is allowed to be provisioned,then euthanasia will affect vulnerable populations exactly like nonprincipled arguments claim.Therefore,despite sharing aspects with each type of argument in the extant literature,my argument against euthanasia can be categorized as neither principled nor nonprincipled,which makes it significant because it may be the first of a new category of argument against the concept and practice to enter the discourse on euthanasia.As a corollary,since we prove that unbearable suffering logically entails death,when it is authentic signifying that death is imminent,because euthanasia’s only purpose is to end unbearable suffering by inducing death,euthanasia is completely obviated.