To address the current issues of inaccurate segmentation and the limited applicability of segmentation methods for building facades in point clouds, we propose a facade segmentation algorithm based on optimal dual-sca...To address the current issues of inaccurate segmentation and the limited applicability of segmentation methods for building facades in point clouds, we propose a facade segmentation algorithm based on optimal dual-scale feature descriptors. First, we select the optimal dual-scale descriptors from a range of feature descriptors. Next, we segment the facade according to the threshold value of the chosen optimal dual-scale descriptors. Finally, we use RANSAC (Random Sample Consensus) to fit the segmented surface and optimize the fitting result. Experimental results show that, compared to commonly used facade segmentation algorithms, the proposed method yields more accurate segmentation results, providing a robust data foundation for subsequent 3D model reconstruction of buildings.展开更多
Federated Learning(FL),as an emergent paradigm in privacy-preserving machine learning,has garnered significant interest from scholars and engineers across both academic and industrial spheres.Despite its innovative ap...Federated Learning(FL),as an emergent paradigm in privacy-preserving machine learning,has garnered significant interest from scholars and engineers across both academic and industrial spheres.Despite its innovative approach to model training across distributed networks,FL has its vulnerabilities;the centralized server-client architecture introduces risks of single-point failures.Moreover,the integrity of the global model—a cornerstone of FL—is susceptible to compromise through poisoning attacks by malicious actors.Such attacks and the potential for privacy leakage via inference starkly undermine FL’s foundational privacy and security goals.For these reasons,some participants unwilling use their private data to train a model,which is a bottleneck in the development and industrialization of federated learning.Blockchain technology,characterized by its decentralized ledger system,offers a compelling solution to these issues.It inherently prevents single-point failures and,through its incentive mechanisms,motivates participants to contribute computing power.Thus,blockchain-based FL(BCFL)emerges as a natural progression to address FL’s challenges.This study begins with concise introductions to federated learning and blockchain technologies,followed by a formal analysis of the specific problems that FL encounters.It discusses the challenges of combining the two technologies and presents an overview of the latest cryptographic solutions that prevent privacy leakage during communication and incentives in BCFL.In addition,this research examines the use of BCFL in various fields,such as the Internet of Things and the Internet of Vehicles.Finally,it assesses the effectiveness of these solutions.展开更多
Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B ...Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B by examining both its temporal and spectral consistency with the predictions of the model.As one of the recently confirmed GRBs observed by our GRID CubeSat mission,GRB 220408B is noteworthy as it exhibits three apparently similar emission episodes.Furthermore,the similarities are reinforced by their strong temporal correlations and similar features in terms of spectral evolution and spectral lags.Our analysis demonstrates that these features can be well explained by the modulated emission of a Fast-Rise-Exponential-Decay(FRED)shape light curve intrinsically produced by a precessing jet with a precession period of 18.4_(-0.2)~(+0.2)s,a nutation period of11.1_(-0.2)~(+0.2)s and viewed off-axis.This study provides a straightforward explanation for the complex yet similar multiepisode GRB light curves.展开更多
With the emphasis on energy and environmental protection,energy-conservation and emission-reduction become vital issues for industrial development.Moreover,with the development of legislation on marine environment,the...With the emphasis on energy and environmental protection,energy-conservation and emission-reduction become vital issues for industrial development.Moreover,with the development of legislation on marine environment,the marine diesel engine has become focusing on energy saving and emission reduction for ships.For low-speed diesel engines under high load,waste heat from exhaust gas can be recovered by the compact and efficient gas turbine.In this paper,the matching design research between low speed diesel engine and gas turbine is carried out.To balance efficiency and compactness,the impeller was adjusted and generated by ANSYS BLADEGEN,based on 1D thermodynamic design.And the 1D calculation is similar to the ANSYS CFX simulation result:the total-static efficiency is 73.8%compared to 76.7%.Moreover,the flow separation happened at the impeller suction side and created vortex due to the high incidence angle.The off-design operating point simulation of the turbine shows though the pressure ratio increase will cause the efficiency to decline a little,the total shaft power rises.In sum,this paper worked out a power turbine suitable for a low-speed diesel engine according to the turbine character matching design and simulation,which provides foundation to the construction of a steady operation of waste heat recovery system for marine diesel engine.展开更多
Objective:To illustrate the effect of geniposide (GP) and panax notoginseng saponins (PNS) on estrogen receptors (ER) including ERα and ERβ within the cytoplasm and nucleus of SH-SY5Y cells.Methods:Immunofluorescenc...Objective:To illustrate the effect of geniposide (GP) and panax notoginseng saponins (PNS) on estrogen receptors (ER) including ERα and ERβ within the cytoplasm and nucleus of SH-SY5Y cells.Methods:Immunofluorescence was used to observe the distribution of ERα and ERβ in cytoplasm and nucleus,but Western blot was only for ERβ detection.q-PCR was applied to detect NR3C1,S100A6 and LGALS1downstream mRNA gene expression levels of ER.Results:Through analyzing fluorescence intensity under the administration of GP and PNS in SHSY5Y cells,we found that the distribution of ERα has not been affected.We also discovered that GP and/or PNS significantly stimulated the transportation of ERβ into the nucleus in a timedependent manner (all P <.001).When SH-SY5Y cells were treated with supplements of GP,PNS,GP + PNS at 15 minutes,30 minutes and 45 minutes,the distribution of ERβ in the nucleus significantly increased compared with that in control group (all P <.001).Evidently,treatment with GP,PNS,GP + PNS was able to significantly increase the levels of ERβ protein within the nucleus compared with control group at both 30 minutes and 45 minutes intervals (all P <.001).Furthermore,GP and PNS showed signs of activating to NR3C1 and LGALS1,two genes downstream of ER.It is possible that the 5100A6 gene mainly encoded the downstream gene in ERα's signaling pathway,which was not affected after the treatment of GP and/or PNS.Conclusion:The distribution and expression of ERβ has been modulated under the administration of GP + PNS within the SH-SY5Y cells,whereas ERα has not.GP and PNS in combination may play an estrogenic-like effect with selectivity on ERβ modulation.展开更多
Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–sil...Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate(CMAS)melt corrosion at high service temperatures,which impedes their practical application.In this work,we developed a series of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40%relative to that of RE_(2)Zr_(2)O_(7)but also exhibited improved resistance to CMAS corrosion.The increase in toughness arises from multiple mechanisms,such as ferroelastic toughening,fine-grain strengthening,and residual stress toughening,all of which trigger more crack defects and energy consumption.Additionally,the CMAS penetration depth of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites is approximately 36%lower than that of RE_(2)Zr_(2)O_(7).Al–O constituents in composites can capture CaO,SiO_(2),and MgO in CMAS melts and increase their viscosity,resulting in enhanced CMAS corrosion resistance.The thermophysical properties of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites were also investigated,and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt%Y_(2)O_(3)partially stabilized ZrO2(YSZ),indicating their potential as TBC materials.展开更多
To the Editor:As society continues to advance,individuals are increasingly exposed to various stressors in their personal and professional lives.The World Health Organization claims that nearly 1 billion people worldw...To the Editor:As society continues to advance,individuals are increasingly exposed to various stressors in their personal and professional lives.The World Health Organization claims that nearly 1 billion people worldwide suffer from mental disorders in 2019,including 14%of the world’s adolescents.[1]Depression among Chinese adults is a serious public health challenge that requires urgent attention.Due to the combined inuence of various life stresses and unhealthy lifestyles,individuals face a signicantly increased risk of developing depression.[2]Depression is often misdiagnosed because its symptoms overlap with those of other mental health conditions.A misdiagnosis of depression can have a signicant impact on all aspects of an individual’s life.In children,a misdiagnosis can lead to inappropriate academic interventions or unnecessary treatments that can adversely affect their school life and overall well-being.For adults,a misdiagnosis can strain relationships.展开更多
Meningitis is one of the major threats to prenatal and newborn babies,causing more than 300,000 infant deaths worldwide annually.Survivors often suffer from long-term neuron-developmental disorders caused by the infec...Meningitis is one of the major threats to prenatal and newborn babies,causing more than 300,000 infant deaths worldwide annually.Survivors often suffer from long-term neuron-developmental disorders caused by the infection[1–3].Bacterial meningitis,a prevalent form of this condition,remains a major global public health challenge,despite significant progress in combating specific pathogens[4].In infants,where systemic adaptive immunity is not fully developed,brain macrophage plays a crucial role in defensing pathogen infection in this vital organ[5,6].However,our understanding of the precise markers that reflect the distinct contributions of various macrophage populations in the neonatal brain remains incomplete.展开更多
Photodynamic Therapy(PDT)holds a great promise for cancer patients,however,due to the hypoxic characteristics of most solid tumors and the limited penetration depth of light in tissues,the extensive clinical applicati...Photodynamic Therapy(PDT)holds a great promise for cancer patients,however,due to the hypoxic characteristics of most solid tumors and the limited penetration depth of light in tissues,the extensive clinical application of PDT is limited.Herein,we report microwave induced copper-cysteamine(Cu-Cy)nanoparticles-based PDT as a promising cancer treatment to overcome cancer resistance in combination with ferroptosis.The treatment efficiency of Cu-Cy-mediated microwave dynamic therapy(MWDT)tested on HCT15 colorectal cancer(CRC)cells via cell titer-blue cell viability assay and live/dead assay reveal that Cu-Cy upon MW irradiation can effectively destroy HCT15 CRC cells with average IC-50 values of 20μg/mL.The cytotoxicity of Cu-Cy to tumor cells after MW stimulation can be alleviated by ferroptosis inhibitor.Furthermore,Cu-Cy mediated MWDT could deplete glutathione peroxide 4(GPX4)and enhance lipid peroxides(LPO)and malondialdehyde(MDA).Our findings demonstrate that MW-activated Cu-Cy killed CRC cells by inducing ferroptosis.The superior in vivo antitumor efficacy of the Cu-Cy was corroborated by a HCT15 tumor-bearing mice model.Immunohistochemical experiments showed that the GPX4 expression level in Cu-Cy+MW group was significantly lower than that in other groups.Overall,these findings demonstrate that Cu-Cy nanoparticles have a safe and promising clinical application prospect in MWDT for deep-seated tumors and effectively inhibit tumor cell proliferation by inducing ferroptosis,which provides a potential solution for cancer resistance.展开更多
Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low pow...Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low power consumption,RISs are expected to greatly enlarge signal coverage,improve system capacity,andincrease energy efficiency.In this article,we systematically overview the emerging RIS technology with the focuson its key basics,nine fundamental issues,and one critical problem.Specifically,we first explain the RIS basics,including its working principles,hardware structures,and potential benefits for communications.Based on thesebasics,nine fundamental issues of RISs,such as“What’s the differences between RISs and massive MIMO?”and“Is RIS really intelligent?”,are explicitly addressed to elaborate its technical features,distinguish it from existingtechnologies,and clarify some misunderstandings in the literature.Then,one critical problem of RISs is revealedthat,due to the“multiplicative fading”effect,existing passive RISs can hardly achieve visible performance gains inmany communication scenarios with strong direct links.To address this critical problem,a potential solution calledactive RISs is introduced,and its effectiveness is demonstrated by numerical simulations.展开更多
The collaboration of multiple Reconfigurable Intelligent Surfaces(RISs)and Access Points(APs)enjoys advantages of capacity enhancement,power saving,etc.,making the RIS-assisted cell-free network an important architect...The collaboration of multiple Reconfigurable Intelligent Surfaces(RISs)and Access Points(APs)enjoys advantages of capacity enhancement,power saving,etc.,making the RIS-assisted cell-free network an important architecture for future communications.Similar to most existing works on RIS-assisted communications,the multi-hop link among RISs,i.e.,the reflecting link including more than one RISs,is usually ignored in RIS-assisted cell-free networks.In these scenarios,however,since multiple RISs are closely deployed,we find that the multi-hop channels should not be simply ignored due to their potential for capacity improvement.Unfortunately,to the best of our knowledge,there is no work exploring the multi-hop transmission of RIS-assisted cell-free networks.To fill in this blank,we investigate the multi-hop transmission of RIS-assisted cell-free networks,including the multi-hop channel model and the corresponding beamforming design.Specifically,we propose a general multi-hop transmission model,which takes the direct links,single-reflecting links,and multi-hop links into account.Based on this model,we formulate a beamforming design problem in an RIS-assisted cell-free network,which allows us to maximize the multi-user sum-rate with considering the impact of multi-hop channels.To address the non-convexity of the formulated problem,a joint active and passive beamforming scheme is proposed to solve the problem.Particularly,by utilizing fractional programming,we decouple the coupled beamforming parameters in the problem,and then these parameters are alternately optimized until the convergence of the sum-rate.Simulation results verify that the consideration for multi-hop links is necessary,and the capacity performance of the proposed scheme is 20%higher than those of the existing schemes.展开更多
To the Editor:Major depressive disorder(MDD)is a common mood disorder that contributes considerably to disability worldwide.Abnormalities in either structural connectivity or functional connectivity in the brains of p...To the Editor:Major depressive disorder(MDD)is a common mood disorder that contributes considerably to disability worldwide.Abnormalities in either structural connectivity or functional connectivity in the brains of patients with MDD have been widely reported,which greatly extends our knowledge of the pathophysiology of MDD.展开更多
Hypersonic airbreathing propulsion is one of the top techniques for future aerospace flight, but there are still no practical engines after seventy years’ development. Two critical issues are identified to be the bar...Hypersonic airbreathing propulsion is one of the top techniques for future aerospace flight, but there are still no practical engines after seventy years’ development. Two critical issues are identified to be the barriers for the ramjet-based engine that has been taken as the most potential concept of the hypersonic propulsion for decades. One issue is the upstream-traveling shock wave that develops from spontaneous waves resulting from continuous heat releases in combustors and can induce unsteady combustion that may lead to engine surging during scramjet engine operation.The other is the scramjet combustion mode that cannot satisfy thrust needs of hypersonic vehicles since its thermos-efficiency decreases as the flight Mach number increases. The two criteria are proposed for the ramjet-based hypersonic propulsion to identify combustion modes and avoid thermal choking. A standing oblique detonation ramjet(Sodramjet) engine concept is proposed based on the criteria by replacing diffusive combustion with an oblique detonation that is a unique pressure-gain phenomenon in nature. The Sodramjet engine model is developed with several flow control techniques, and tested successfully with the hypersonic flight-duplicated shock tunnel.The experimental data show that the Sodramjet engine model works steadily, and an oblique detonation can be made stationary in the engine combustor and is controllable. This research demonstrates the Sodramjet engine is a promising concept and can be operated stably with high thermal efficiency at hypersonic flow conditions.展开更多
Modular Solar-Powered Aircraft(M-SPA)is a kind of High-Altitude Long-Endurance(HALE)aircraft which exploits the mission advantage of swarm UAV and the HALE advantage of large aspect-ratio SPA.M-SPA’s separated mode a...Modular Solar-Powered Aircraft(M-SPA)is a kind of High-Altitude Long-Endurance(HALE)aircraft which exploits the mission advantage of swarm UAV and the HALE advantage of large aspect-ratio SPA.M-SPA’s separated mode and combined mode give it the potential to maximize the mission efficiency with limited solar energy.In this paper,firstly,oriented by the mission of maximizing the cruise area,the overall design of the M-SPA is modeled,including the energy model,the aerodynamic model and the flight environment settings.Secondly,by analyzing the energy consumption of the flight modes,we design a multi-phase flight mission strategy.Then,a 24-hour three-dimensional(3D)flight profile of the M-SPA is optimized,including the sub-SPA cooperative path planning in the separation mode.Finally,inspired by the Traveling Salesman Problem(TSP),an improved Ant Colony Algorithm(ACA)is exploited to find the optimal path for each sub-SPA,which is further developed into a dynamic separation and combination scheme for the M-SPA.The simulation results show that the mission performance of the M-SPA outperforms that of the conventional SPA,and explicitly,the mission coverage of the M-SPA is slightly less than a linear increase under comparable simulation conditions.展开更多
The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure.Consider a primary beam in the wing of large aspect ratio,where 100 lithium batteries are assembled.In ...The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure.Consider a primary beam in the wing of large aspect ratio,where 100 lithium batteries are assembled.In the proposed integrated optimization,the batteries are considered here as parts of the load-carrying structure.The corresponding mechanical behaviors are simulated in the structural design and described with super-elements.The batteries layout and the structural topology are then introduced as mixed design variables and optimized simultaneously to achieve an accordant load-carrying path.Geometrical nonlinearity is considered due to the large deformation.Different periodic structural configurations are tested in the optimization in order to meet the structural manufacturing and assembly convenience.The optimized designs are rebuilt and tested in different load cases.Maintaining the same structural weight,the global mechanical performances are improved greatly compared with the initial design.展开更多
High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-cent...High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-centered cubic(bcc)structured Mo_(0.5)Nb Ti VCr_(0.25)and Mo_(0.5)Nb Ti V_(0.5)Zr_(0.25)HEAs were fabricated.Helium-ion irradiation was performed on the two HEAs to simulate neutron irradiation,and the crystal structure,hardness,and microstructure evolution were investigated.The crystal structure of the Mo_(0.5)NbTiVCr_(0.25)HEA remained stable at low fluences,while amorphization may occur at high fluences in the two HEAs.The irradiation hardening value of the Mo_(0.5)NbTiVCr_(0.25)was 0.77 GPa at fluences of 1×10^(17)ions/cm^(2)and 1.49 GPa at fluences of 5×10^(17)ions/cm^(2),while the hardening value of the Mo_(0.5)NbTiV_(0.5)Zr_(0.25)was 1.36 GPa at ion fluences of 5×10^(17)ions/cm^(2).In comparison with most of the conventional alloys,the two HEAs showed slight irradiation hardening.The helium bubbles and dislocation loops with small size were observed in the two HEAs after irradiation.This is the first time to report the formation of a dislocation loop in bcc-structure HEAs after irradiation.However,voids and precipitates were not observed in the two HEAs which could be ascribed to the high lattice distortion and compositional complexity of HEAs.This research revealed that the two HEAs show outstanding irradiation resistance,which may be promising accident-tolerant fuel cladding materials.展开更多
In this study,a theoretical method is proposed to solve shock relations coupled with chemical equilibrium.Not only shock waves in dissociated flows but also detonation waves in combustive mixtures can be solved.The gl...In this study,a theoretical method is proposed to solve shock relations coupled with chemical equilibrium.Not only shock waves in dissociated flows but also detonation waves in combustive mixtures can be solved.The global iterative solving process is specially designed to mimic the physical and chemical process in reactive shock waves to ensure good stability and fast convergence in the proposed method.Within each global step,the single-variable equations of normal and oblique shock relations are derived and solved with the Newton iteration method to reduce the complexity of the problems,and the minimization of free energy method of NASA(National Aeronautics and Space Administration)is adopted to solve equilibrium compositions.It is demonstrated that the convergent process is stable and very close to the real chemical-kinetic process,and high accuracy is achieved in the solutions of normal and oblique reactive shock waves.Moreover,the proposed theoretical method has also been applied to many problems associated with reactive shocks,including the stability of oblique detonation wave,bow detonation over a sphere,and shock reflection in dissociated air.The great importance of using chemical equilibrium to theoretically predict the theoretical range of the wedge angle for a standing oblique detonation wave(the standing window of the oblique detonation wave),the stand-off distance of bow detonation wave and the transition criterion of shock reflection in dissociated air with high accuracy have been addressed.展开更多
文摘To address the current issues of inaccurate segmentation and the limited applicability of segmentation methods for building facades in point clouds, we propose a facade segmentation algorithm based on optimal dual-scale feature descriptors. First, we select the optimal dual-scale descriptors from a range of feature descriptors. Next, we segment the facade according to the threshold value of the chosen optimal dual-scale descriptors. Finally, we use RANSAC (Random Sample Consensus) to fit the segmented surface and optimize the fitting result. Experimental results show that, compared to commonly used facade segmentation algorithms, the proposed method yields more accurate segmentation results, providing a robust data foundation for subsequent 3D model reconstruction of buildings.
基金supported by High-performance Reliable Multi-Party Secure Computing Technology and Product Project for Industrial Internet No.TC220H056.
文摘Federated Learning(FL),as an emergent paradigm in privacy-preserving machine learning,has garnered significant interest from scholars and engineers across both academic and industrial spheres.Despite its innovative approach to model training across distributed networks,FL has its vulnerabilities;the centralized server-client architecture introduces risks of single-point failures.Moreover,the integrity of the global model—a cornerstone of FL—is susceptible to compromise through poisoning attacks by malicious actors.Such attacks and the potential for privacy leakage via inference starkly undermine FL’s foundational privacy and security goals.For these reasons,some participants unwilling use their private data to train a model,which is a bottleneck in the development and industrialization of federated learning.Blockchain technology,characterized by its decentralized ledger system,offers a compelling solution to these issues.It inherently prevents single-point failures and,through its incentive mechanisms,motivates participants to contribute computing power.Thus,blockchain-based FL(BCFL)emerges as a natural progression to address FL’s challenges.This study begins with concise introductions to federated learning and blockchain technologies,followed by a formal analysis of the specific problems that FL encounters.It discusses the challenges of combining the two technologies and presents an overview of the latest cryptographic solutions that prevent privacy leakage during communication and incentives in BCFL.In addition,this research examines the use of BCFL in various fields,such as the Internet of Things and the Internet of Vehicles.Finally,it assesses the effectiveness of these solutions.
基金support by the National Key Research and Development Programs of China(2022YFF0711404,2022SKA0130102)the National SKA Program of China(2022SKA0130100)+4 种基金the National Natural Science Foundation of China(grant Nos.11833003,U2038105,U1831135,12121003)the science research grants from the China Manned Space Project with NO.CMS-CSST-2021-B11the Fundamental Research Funds for the Central Universitiesthe Program for Innovative Talents and Entrepreneur in Jiangsusupported by the National Postdoctoral Program for Innovative Talents(grant No.BX20200164)。
文摘Jet precession has previously been proposed to explain the apparently repeating features in the light curves of a few gamma-ray bursts(GRBs).In this paper,we further apply the precession model to a bright GRB 220408B by examining both its temporal and spectral consistency with the predictions of the model.As one of the recently confirmed GRBs observed by our GRID CubeSat mission,GRB 220408B is noteworthy as it exhibits three apparently similar emission episodes.Furthermore,the similarities are reinforced by their strong temporal correlations and similar features in terms of spectral evolution and spectral lags.Our analysis demonstrates that these features can be well explained by the modulated emission of a Fast-Rise-Exponential-Decay(FRED)shape light curve intrinsically produced by a precessing jet with a precession period of 18.4_(-0.2)~(+0.2)s,a nutation period of11.1_(-0.2)~(+0.2)s and viewed off-axis.This study provides a straightforward explanation for the complex yet similar multiepisode GRB light curves.
文摘With the emphasis on energy and environmental protection,energy-conservation and emission-reduction become vital issues for industrial development.Moreover,with the development of legislation on marine environment,the marine diesel engine has become focusing on energy saving and emission reduction for ships.For low-speed diesel engines under high load,waste heat from exhaust gas can be recovered by the compact and efficient gas turbine.In this paper,the matching design research between low speed diesel engine and gas turbine is carried out.To balance efficiency and compactness,the impeller was adjusted and generated by ANSYS BLADEGEN,based on 1D thermodynamic design.And the 1D calculation is similar to the ANSYS CFX simulation result:the total-static efficiency is 73.8%compared to 76.7%.Moreover,the flow separation happened at the impeller suction side and created vortex due to the high incidence angle.The off-design operating point simulation of the turbine shows though the pressure ratio increase will cause the efficiency to decline a little,the total shaft power rises.In sum,this paper worked out a power turbine suitable for a low-speed diesel engine according to the turbine character matching design and simulation,which provides foundation to the construction of a steady operation of waste heat recovery system for marine diesel engine.
基金This study has been financially supported by the National Natural Science Foundation of China(81473546)International Collaborative Base,Ministry of Science and Technology of the People's Republic of China(2015B01022)+1 种基金Regional Collaborative Innovation Center of Tibetan Medicine(2017XTCX012)the Fundamental Research Funds for the Central Universities(2018-JYBZZ-XJSJJ011).
文摘Objective:To illustrate the effect of geniposide (GP) and panax notoginseng saponins (PNS) on estrogen receptors (ER) including ERα and ERβ within the cytoplasm and nucleus of SH-SY5Y cells.Methods:Immunofluorescence was used to observe the distribution of ERα and ERβ in cytoplasm and nucleus,but Western blot was only for ERβ detection.q-PCR was applied to detect NR3C1,S100A6 and LGALS1downstream mRNA gene expression levels of ER.Results:Through analyzing fluorescence intensity under the administration of GP and PNS in SHSY5Y cells,we found that the distribution of ERα has not been affected.We also discovered that GP and/or PNS significantly stimulated the transportation of ERβ into the nucleus in a timedependent manner (all P <.001).When SH-SY5Y cells were treated with supplements of GP,PNS,GP + PNS at 15 minutes,30 minutes and 45 minutes,the distribution of ERβ in the nucleus significantly increased compared with that in control group (all P <.001).Evidently,treatment with GP,PNS,GP + PNS was able to significantly increase the levels of ERβ protein within the nucleus compared with control group at both 30 minutes and 45 minutes intervals (all P <.001).Furthermore,GP and PNS showed signs of activating to NR3C1 and LGALS1,two genes downstream of ER.It is possible that the 5100A6 gene mainly encoded the downstream gene in ERα's signaling pathway,which was not affected after the treatment of GP and/or PNS.Conclusion:The distribution and expression of ERβ has been modulated under the administration of GP + PNS within the SH-SY5Y cells,whereas ERα has not.GP and PNS in combination may play an estrogenic-like effect with selectivity on ERβ modulation.
基金supported by the National Key R&D Program of China(No.2021YFB3702300)the National Natural Science Foundation of China(No.52022042)+2 种基金the Project of the Science Center for Gas Turbine(No.HT-P2022-DB-Ⅳ-002-001)the National Science and Technology Major Project(No.J2019-Ⅶ−0008-0148)the Research on the Development and Preparation of Thermal Barrier Coating Materials on New Generation of Heavy-duty Gas Turbines(No.UGTC-HT-WXKT-2022-032).
文摘Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate(CMAS)melt corrosion at high service temperatures,which impedes their practical application.In this work,we developed a series of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40%relative to that of RE_(2)Zr_(2)O_(7)but also exhibited improved resistance to CMAS corrosion.The increase in toughness arises from multiple mechanisms,such as ferroelastic toughening,fine-grain strengthening,and residual stress toughening,all of which trigger more crack defects and energy consumption.Additionally,the CMAS penetration depth of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites is approximately 36%lower than that of RE_(2)Zr_(2)O_(7).Al–O constituents in composites can capture CaO,SiO_(2),and MgO in CMAS melts and increase their viscosity,resulting in enhanced CMAS corrosion resistance.The thermophysical properties of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites were also investigated,and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt%Y_(2)O_(3)partially stabilized ZrO2(YSZ),indicating their potential as TBC materials.
基金The Project of Natural Science Foundation of Hunan Province(No.CX20221185)and the Science Foundation of Hunan Province(Nos.2022JJ70072 and 2021JJ70151)supported this work.
文摘To the Editor:As society continues to advance,individuals are increasingly exposed to various stressors in their personal and professional lives.The World Health Organization claims that nearly 1 billion people worldwide suffer from mental disorders in 2019,including 14%of the world’s adolescents.[1]Depression among Chinese adults is a serious public health challenge that requires urgent attention.Due to the combined inuence of various life stresses and unhealthy lifestyles,individuals face a signicantly increased risk of developing depression.[2]Depression is often misdiagnosed because its symptoms overlap with those of other mental health conditions.A misdiagnosis of depression can have a signicant impact on all aspects of an individual’s life.In children,a misdiagnosis can lead to inappropriate academic interventions or unnecessary treatments that can adversely affect their school life and overall well-being.For adults,a misdiagnosis can strain relationships.
基金supported by grants from the National Key Research and Development Program of China(2019YFA0802900)National Natural Science Foundation of China(32122035,32000669,32070942)a Jiangsu Provincial Science and Technology Plan Special Fund(BK20232018).
文摘Meningitis is one of the major threats to prenatal and newborn babies,causing more than 300,000 infant deaths worldwide annually.Survivors often suffer from long-term neuron-developmental disorders caused by the infection[1–3].Bacterial meningitis,a prevalent form of this condition,remains a major global public health challenge,despite significant progress in combating specific pathogens[4].In infants,where systemic adaptive immunity is not fully developed,brain macrophage plays a crucial role in defensing pathogen infection in this vital organ[5,6].However,our understanding of the precise markers that reflect the distinct contributions of various macrophage populations in the neonatal brain remains incomplete.
基金the support by the Natural Science Foundation of China(81773293,81873640,81970569,82000756)Natural Science Foundation of Hunan Province,No.2022JJ40700+2 种基金the Key Project of Science and Technology Program of Hunan Provincial Science and Technology Department(2015GK3117,2017WK2063)the supports from Guangxi Jialouyuan Medical Inc.,Solgrothe distinguished award from UT Arlington as well as ROSFORCURE Inc.
文摘Photodynamic Therapy(PDT)holds a great promise for cancer patients,however,due to the hypoxic characteristics of most solid tumors and the limited penetration depth of light in tissues,the extensive clinical application of PDT is limited.Herein,we report microwave induced copper-cysteamine(Cu-Cy)nanoparticles-based PDT as a promising cancer treatment to overcome cancer resistance in combination with ferroptosis.The treatment efficiency of Cu-Cy-mediated microwave dynamic therapy(MWDT)tested on HCT15 colorectal cancer(CRC)cells via cell titer-blue cell viability assay and live/dead assay reveal that Cu-Cy upon MW irradiation can effectively destroy HCT15 CRC cells with average IC-50 values of 20μg/mL.The cytotoxicity of Cu-Cy to tumor cells after MW stimulation can be alleviated by ferroptosis inhibitor.Furthermore,Cu-Cy mediated MWDT could deplete glutathione peroxide 4(GPX4)and enhance lipid peroxides(LPO)and malondialdehyde(MDA).Our findings demonstrate that MW-activated Cu-Cy killed CRC cells by inducing ferroptosis.The superior in vivo antitumor efficacy of the Cu-Cy was corroborated by a HCT15 tumor-bearing mice model.Immunohistochemical experiments showed that the GPX4 expression level in Cu-Cy+MW group was significantly lower than that in other groups.Overall,these findings demonstrate that Cu-Cy nanoparticles have a safe and promising clinical application prospect in MWDT for deep-seated tumors and effectively inhibit tumor cell proliferation by inducing ferroptosis,which provides a potential solution for cancer resistance.
基金supported by the National Key Research and Development Program of China(No.2020YFB1805005)the National Natural Science Foundation of China(No.62031019)the European Commission through the H2020-MSCA-ITN META WIRELESS Research Project(No.956256)。
文摘Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low power consumption,RISs are expected to greatly enlarge signal coverage,improve system capacity,andincrease energy efficiency.In this article,we systematically overview the emerging RIS technology with the focuson its key basics,nine fundamental issues,and one critical problem.Specifically,we first explain the RIS basics,including its working principles,hardware structures,and potential benefits for communications.Based on thesebasics,nine fundamental issues of RISs,such as“What’s the differences between RISs and massive MIMO?”and“Is RIS really intelligent?”,are explicitly addressed to elaborate its technical features,distinguish it from existingtechnologies,and clarify some misunderstandings in the literature.Then,one critical problem of RISs is revealedthat,due to the“multiplicative fading”effect,existing passive RISs can hardly achieve visible performance gains inmany communication scenarios with strong direct links.To address this critical problem,a potential solution calledactive RISs is introduced,and its effectiveness is demonstrated by numerical simulations.
基金This work was supported by the National Key Research and Development Program of China(No.2020YB1807201)the National Natural Science Foundation of China(No.62031019)the European Commission through the H2020-MSCA-ITN META WIRELESS Research Project(No.956256).
文摘The collaboration of multiple Reconfigurable Intelligent Surfaces(RISs)and Access Points(APs)enjoys advantages of capacity enhancement,power saving,etc.,making the RIS-assisted cell-free network an important architecture for future communications.Similar to most existing works on RIS-assisted communications,the multi-hop link among RISs,i.e.,the reflecting link including more than one RISs,is usually ignored in RIS-assisted cell-free networks.In these scenarios,however,since multiple RISs are closely deployed,we find that the multi-hop channels should not be simply ignored due to their potential for capacity improvement.Unfortunately,to the best of our knowledge,there is no work exploring the multi-hop transmission of RIS-assisted cell-free networks.To fill in this blank,we investigate the multi-hop transmission of RIS-assisted cell-free networks,including the multi-hop channel model and the corresponding beamforming design.Specifically,we propose a general multi-hop transmission model,which takes the direct links,single-reflecting links,and multi-hop links into account.Based on this model,we formulate a beamforming design problem in an RIS-assisted cell-free network,which allows us to maximize the multi-user sum-rate with considering the impact of multi-hop channels.To address the non-convexity of the formulated problem,a joint active and passive beamforming scheme is proposed to solve the problem.Particularly,by utilizing fractional programming,we decouple the coupled beamforming parameters in the problem,and then these parameters are alternately optimized until the convergence of the sum-rate.Simulation results verify that the consideration for multi-hop links is necessary,and the capacity performance of the proposed scheme is 20%higher than those of the existing schemes.
基金Key Research and Development Program of Science and Technology Department of Sichuan Province(Nos.22ZDYF1531 and 22ZDYF1696)Program of Chengdu Science and Technology(No.2021-YF05-00272-SN)+3 种基金National Natural Science Foundation of China(No.82001432)China Postdoctoral Science Foundation(Nos.2020TQ0213 and 2020M683319)Open Project Program of the National Laboratory of Pattern Recognition(No.202000034)West China Hospital Postdoctoral Science Foundation(No.2020HXBH104)
文摘To the Editor:Major depressive disorder(MDD)is a common mood disorder that contributes considerably to disability worldwide.Abnormalities in either structural connectivity or functional connectivity in the brains of patients with MDD have been widely reported,which greatly extends our knowledge of the pathophysiology of MDD.
基金supported by the National Natural Science Foundation of China (No. 11532014)。
文摘Hypersonic airbreathing propulsion is one of the top techniques for future aerospace flight, but there are still no practical engines after seventy years’ development. Two critical issues are identified to be the barriers for the ramjet-based engine that has been taken as the most potential concept of the hypersonic propulsion for decades. One issue is the upstream-traveling shock wave that develops from spontaneous waves resulting from continuous heat releases in combustors and can induce unsteady combustion that may lead to engine surging during scramjet engine operation.The other is the scramjet combustion mode that cannot satisfy thrust needs of hypersonic vehicles since its thermos-efficiency decreases as the flight Mach number increases. The two criteria are proposed for the ramjet-based hypersonic propulsion to identify combustion modes and avoid thermal choking. A standing oblique detonation ramjet(Sodramjet) engine concept is proposed based on the criteria by replacing diffusive combustion with an oblique detonation that is a unique pressure-gain phenomenon in nature. The Sodramjet engine model is developed with several flow control techniques, and tested successfully with the hypersonic flight-duplicated shock tunnel.The experimental data show that the Sodramjet engine model works steadily, and an oblique detonation can be made stationary in the engine combustor and is controllable. This research demonstrates the Sodramjet engine is a promising concept and can be operated stably with high thermal efficiency at hypersonic flow conditions.
基金supported by the National Natural Science Foundation of China(Nos.61901448,61871401,12002340).
文摘Modular Solar-Powered Aircraft(M-SPA)is a kind of High-Altitude Long-Endurance(HALE)aircraft which exploits the mission advantage of swarm UAV and the HALE advantage of large aspect-ratio SPA.M-SPA’s separated mode and combined mode give it the potential to maximize the mission efficiency with limited solar energy.In this paper,firstly,oriented by the mission of maximizing the cruise area,the overall design of the M-SPA is modeled,including the energy model,the aerodynamic model and the flight environment settings.Secondly,by analyzing the energy consumption of the flight modes,we design a multi-phase flight mission strategy.Then,a 24-hour three-dimensional(3D)flight profile of the M-SPA is optimized,including the sub-SPA cooperative path planning in the separation mode.Finally,inspired by the Traveling Salesman Problem(TSP),an improved Ant Colony Algorithm(ACA)is exploited to find the optimal path for each sub-SPA,which is further developed into a dynamic separation and combination scheme for the M-SPA.The simulation results show that the mission performance of the M-SPA outperforms that of the conventional SPA,and explicitly,the mission coverage of the M-SPA is slightly less than a linear increase under comparable simulation conditions.
基金This work is supported by Key Project of Natural Science Foundation of China(Nos.51790171,51761145111,51735005)Natural Science Foundation of China for Excellent Young Scholars(No.11722219).
文摘The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure.Consider a primary beam in the wing of large aspect ratio,where 100 lithium batteries are assembled.In the proposed integrated optimization,the batteries are considered here as parts of the load-carrying structure.The corresponding mechanical behaviors are simulated in the structural design and described with super-elements.The batteries layout and the structural topology are then introduced as mixed design variables and optimized simultaneously to achieve an accordant load-carrying path.Geometrical nonlinearity is considered due to the large deformation.Different periodic structural configurations are tested in the optimization in order to meet the structural manufacturing and assembly convenience.The optimized designs are rebuilt and tested in different load cases.Maintaining the same structural weight,the global mechanical performances are improved greatly compared with the initial design.
基金supported by the Key Program of the Chinese Academy of Sciences(No.ZDRW-CN-2017-1)。
文摘High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-centered cubic(bcc)structured Mo_(0.5)Nb Ti VCr_(0.25)and Mo_(0.5)Nb Ti V_(0.5)Zr_(0.25)HEAs were fabricated.Helium-ion irradiation was performed on the two HEAs to simulate neutron irradiation,and the crystal structure,hardness,and microstructure evolution were investigated.The crystal structure of the Mo_(0.5)NbTiVCr_(0.25)HEA remained stable at low fluences,while amorphization may occur at high fluences in the two HEAs.The irradiation hardening value of the Mo_(0.5)NbTiVCr_(0.25)was 0.77 GPa at fluences of 1×10^(17)ions/cm^(2)and 1.49 GPa at fluences of 5×10^(17)ions/cm^(2),while the hardening value of the Mo_(0.5)NbTiV_(0.5)Zr_(0.25)was 1.36 GPa at ion fluences of 5×10^(17)ions/cm^(2).In comparison with most of the conventional alloys,the two HEAs showed slight irradiation hardening.The helium bubbles and dislocation loops with small size were observed in the two HEAs after irradiation.This is the first time to report the formation of a dislocation loop in bcc-structure HEAs after irradiation.However,voids and precipitates were not observed in the two HEAs which could be ascribed to the high lattice distortion and compositional complexity of HEAs.This research revealed that the two HEAs show outstanding irradiation resistance,which may be promising accident-tolerant fuel cladding materials.
基金co-supported by the National Natural Science Foundation of China (Nos. 11672312, 11772284 and 11532014)the Research Grants Council, Hong Kong, China (No. 152151/16E)the Department of Mechanical Engineering, The Hong Kong Polytechnic University, China (No. G-YBYJ)
文摘In this study,a theoretical method is proposed to solve shock relations coupled with chemical equilibrium.Not only shock waves in dissociated flows but also detonation waves in combustive mixtures can be solved.The global iterative solving process is specially designed to mimic the physical and chemical process in reactive shock waves to ensure good stability and fast convergence in the proposed method.Within each global step,the single-variable equations of normal and oblique shock relations are derived and solved with the Newton iteration method to reduce the complexity of the problems,and the minimization of free energy method of NASA(National Aeronautics and Space Administration)is adopted to solve equilibrium compositions.It is demonstrated that the convergent process is stable and very close to the real chemical-kinetic process,and high accuracy is achieved in the solutions of normal and oblique reactive shock waves.Moreover,the proposed theoretical method has also been applied to many problems associated with reactive shocks,including the stability of oblique detonation wave,bow detonation over a sphere,and shock reflection in dissociated air.The great importance of using chemical equilibrium to theoretically predict the theoretical range of the wedge angle for a standing oblique detonation wave(the standing window of the oblique detonation wave),the stand-off distance of bow detonation wave and the transition criterion of shock reflection in dissociated air with high accuracy have been addressed.
