Particle pollution in air, also sometimes known as fine dust contamination, may cause electric contact failure. Recent research further proved that the fine particle is becoming a major disruption of the electronic co...Particle pollution in air, also sometimes known as fine dust contamination, may cause electric contact failure. Recent research further proved that the fine particle is becoming a major disruption of the electronic connectors in signal transmission system. This paper specifies the connector contact in mobile phone application. To study the contact failure of mobile phone, a series of inspections and analytical research methods are introduced. Special features that cause the contact failure are summarized. Particle accumulation is the main problem; organic material such as lactates from sweat of the human body may act as adhesives to stick the separate particles together and make them adhere on the contact surface; chemical properties of dust cause serious local corrosion. The corrosion products may trap the particles and firmly attach on the contact surface; micro motion frequently occurs at the contact interface. Hard particle can be embedded into the surface, and soft particle could be squeezed and inserted into the contact; silicon compounds in dust play the most important role in forming high resistance regions that lead to failure; deposition of particles depends on the amount of materials, static electricity attracting force and gravity force applied on the particles. Current dust test can hardly reflect the serious contact failure. It is difficult to simulate the complexity of contact failure caused by particle contamination. Thus alternative ways of simulation experiment and improvement of contact reliability are proposed.展开更多
The laser-damage performance of optics is known to be negatively affected by microscale particle contamination induced by the operational environment.This work investigates the properties of particles accumulating in ...The laser-damage performance of optics is known to be negatively affected by microscale particle contamination induced by the operational environment.This work investigates the properties of particles accumulating in various locations near critical optics inside the OMEGA EP grating compressor chamber during quarterly operational periods over a 2-year duration.The particles found were characterized using optical microscopy,scanning electron microscopy and energy dispersive X-ray spectroscopy.The analysis indicates significant concentrations of micrometer-to nanometerscale particles inside the vacuum chamber,with higher values observed near the port leading to the OMEGA EP target chamber.The distribution of the chemical composition of these particles varies between collection periods.Although understanding of the mechanisms of particle generation and transport remains uncertain,the hypothesis is that this particle load represents a risk for contaminating the surfaces of high-value optics located inside the chamber,including the compression gratings and deformable mirrors,and therefore affecting their laser-damage resistance and overall operational lifetime.展开更多
The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation d...The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics（CFD） method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves（EHSVs）, throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process.展开更多
The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary dam...The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary damage probability for optical components. To study the general design basis for a final optics assembly to decrease the risk of filamentary damage, different-sized contamination particles deposited on a component surface are simulated to modulate a 351-nm laser beam based on the optical transmission theory, and the corresponding simulation results are analyzed statistically in terms of the propagation characteristic and the light field intensity distribution of the modulated laser beam. The statistical results show that component thickness and distance between components can to some extent be optimized to reduce the appearance of local high light intensity, and the general design basis of component thickness and arrangement are given for different control levels of particle sizes. Moreover, the statistical results can also predict the laser beam quality approximately under the existing optics design and environmental cleanliness. The optimized design for final optics assembly based on environmental cleanliness level is useful to prolong the lifetime of optics and enhance the output power of high-power laser facilities.展开更多
Human uptake of microplastic particles(MPs)is causing increasing health concerns,and there is mounting pressure to evaluate the associated risks.While MPs can be ingested,breathed in,or drank in,a very direct entrance...Human uptake of microplastic particles(MPs)is causing increasing health concerns,and there is mounting pressure to evaluate the associated risks.While MPs can be ingested,breathed in,or drank in,a very direct entrance channel is available through ingress into the bloodstream.Intravenous infusion usually proceeds from plastic bottles.Many are made of polypropylene(PP),and filtering is applied to limit particle contamination.In this study,we examined the MPs’content of filtrates using a combination of surface-enhanced Raman spectroscopy and scanning electron microscopy.We find that the number of PP particles is significant(∼7500 particles/L).The MP sizes range from 1 to 62μm,with a median of∼8.5μm.About 90%of particles ranged between 1 and 20μm in size,with∼60%in the range 1 to 10μm.We then discuss the potential number of such particles injected and the consequences of their presence in the bloodstream.We highlight the organs for potential deposition,and we discuss possible clinical effects.Our quantitative data are important to help evaluate the toxicity risks associated with MPs and to accurately balance those risks versus the benefits of using intravenous injections.展开更多
Lithium-ion batteries are currently the most widely used energy storage devices due to their superior energy density,long lifespan,and high efficiency.However,the manufacturing defects,caused by production flaws and r...Lithium-ion batteries are currently the most widely used energy storage devices due to their superior energy density,long lifespan,and high efficiency.However,the manufacturing defects,caused by production flaws and raw material impurities can accelerate battery degradation.In extreme cases,these defects may result in severe safety incidents,such as thermal runaway.Metal foreign matter is one of the main types of manufacturing defects,frequently causing internal short circuits in lithium-ion batteries.Among these,copper particles are the most common contaminants.This paper addresses the safety risks posed by manufacturing defects in lithium-ion batteries,analyzes their classification and associated hazards,and reviews the research on metal foreign matter defects,with a focus on copper particle contamination.Furthermore,we summarize the detection methods to identify defective batteries and propose future research directions to address metal foreign matter defects.展开更多
基金Project (No. 50277002) supported by the National Natural ScienceFoundation of China
文摘Particle pollution in air, also sometimes known as fine dust contamination, may cause electric contact failure. Recent research further proved that the fine particle is becoming a major disruption of the electronic connectors in signal transmission system. This paper specifies the connector contact in mobile phone application. To study the contact failure of mobile phone, a series of inspections and analytical research methods are introduced. Special features that cause the contact failure are summarized. Particle accumulation is the main problem; organic material such as lactates from sweat of the human body may act as adhesives to stick the separate particles together and make them adhere on the contact surface; chemical properties of dust cause serious local corrosion. The corrosion products may trap the particles and firmly attach on the contact surface; micro motion frequently occurs at the contact interface. Hard particle can be embedded into the surface, and soft particle could be squeezed and inserted into the contact; silicon compounds in dust play the most important role in forming high resistance regions that lead to failure; deposition of particles depends on the amount of materials, static electricity attracting force and gravity force applied on the particles. Current dust test can hardly reflect the serious contact failure. It is difficult to simulate the complexity of contact failure caused by particle contamination. Thus alternative ways of simulation experiment and improvement of contact reliability are proposed.
基金supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856the University of Rochester+1 种基金the New York State Energy Research and Development Authoritysponsored by an agency of the U.S
文摘The laser-damage performance of optics is known to be negatively affected by microscale particle contamination induced by the operational environment.This work investigates the properties of particles accumulating in various locations near critical optics inside the OMEGA EP grating compressor chamber during quarterly operational periods over a 2-year duration.The particles found were characterized using optical microscopy,scanning electron microscopy and energy dispersive X-ray spectroscopy.The analysis indicates significant concentrations of micrometer-to nanometerscale particles inside the vacuum chamber,with higher values observed near the port leading to the OMEGA EP target chamber.The distribution of the chemical composition of these particles varies between collection periods.Although understanding of the mechanisms of particle generation and transport remains uncertain,the hypothesis is that this particle load represents a risk for contaminating the surfaces of high-value optics located inside the chamber,including the compression gratings and deformable mirrors,and therefore affecting their laser-damage resistance and overall operational lifetime.
基金supported by the National Natural Science Foundation of China(Nos.51620105010,51675019,51575019)the National Basic Research Program of China(No.2014CB046402)the Program 111 of China
文摘The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator（LEHA）. Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics（CFD） method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves（EHSVs）, throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process.
基金supported by the National Natural Science Foundation of China(Grant No.60707019)
文摘The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary damage probability for optical components. To study the general design basis for a final optics assembly to decrease the risk of filamentary damage, different-sized contamination particles deposited on a component surface are simulated to modulate a 351-nm laser beam based on the optical transmission theory, and the corresponding simulation results are analyzed statistically in terms of the propagation characteristic and the light field intensity distribution of the modulated laser beam. The statistical results show that component thickness and distance between components can to some extent be optimized to reduce the appearance of local high light intensity, and the general design basis of component thickness and arrangement are given for different control levels of particle sizes. Moreover, the statistical results can also predict the laser beam quality approximately under the existing optics design and environmental cleanliness. The optimized design for final optics assembly based on environmental cleanliness level is useful to prolong the lifetime of optics and enhance the output power of high-power laser facilities.
基金support from the National Natural Science Foundation of China(22376028,22176036,21976030,and 22006020).
文摘Human uptake of microplastic particles(MPs)is causing increasing health concerns,and there is mounting pressure to evaluate the associated risks.While MPs can be ingested,breathed in,or drank in,a very direct entrance channel is available through ingress into the bloodstream.Intravenous infusion usually proceeds from plastic bottles.Many are made of polypropylene(PP),and filtering is applied to limit particle contamination.In this study,we examined the MPs’content of filtrates using a combination of surface-enhanced Raman spectroscopy and scanning electron microscopy.We find that the number of PP particles is significant(∼7500 particles/L).The MP sizes range from 1 to 62μm,with a median of∼8.5μm.About 90%of particles ranged between 1 and 20μm in size,with∼60%in the range 1 to 10μm.We then discuss the potential number of such particles injected and the consequences of their presence in the bloodstream.We highlight the organs for potential deposition,and we discuss possible clinical effects.Our quantitative data are important to help evaluate the toxicity risks associated with MPs and to accurately balance those risks versus the benefits of using intravenous injections.
基金supported by the National Key R&D Program of China(2021YFB2402002)Beijing Natural Science Foundation(Grant No.L223013).
文摘Lithium-ion batteries are currently the most widely used energy storage devices due to their superior energy density,long lifespan,and high efficiency.However,the manufacturing defects,caused by production flaws and raw material impurities can accelerate battery degradation.In extreme cases,these defects may result in severe safety incidents,such as thermal runaway.Metal foreign matter is one of the main types of manufacturing defects,frequently causing internal short circuits in lithium-ion batteries.Among these,copper particles are the most common contaminants.This paper addresses the safety risks posed by manufacturing defects in lithium-ion batteries,analyzes their classification and associated hazards,and reviews the research on metal foreign matter defects,with a focus on copper particle contamination.Furthermore,we summarize the detection methods to identify defective batteries and propose future research directions to address metal foreign matter defects.
