An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.Thi...An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained.展开更多
The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and t...The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes （MWCNTs） synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 10^4 was obtained. The resolution of the acquired images is -10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.展开更多
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest...During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.展开更多
The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate ...The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate compacting the instrument on a single 10 in. flange. Mean- while some correcting elements in the electron optical system are simplified to reduce the complexities of construction and operation. The sample is set close to ground potential, so that all the electrostatic lenses are easily to float at high voltages. The performance of the microscope in typical low energy electron microscopy, low energy electron diffraction and photoemission electron microscopy modes is demonstrated through several experiments. A lateral resolution of 51 nm is estimated for low energy electron microscopy imaging. With femtosecond laser as light source, the consequent nonlinear photoemission makes this micro-scope also suitable for the observation of optical near field phenomena and a lateral resolution of 110 nm is obtained.展开更多
In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly effi...In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.展开更多
Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 ex...Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 exhibitors from more than 30 countries including China to address the future of cleaner and more inclusive energy.展开更多
To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produce...To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produced by the tandem-accelerator in the China Institute of Atomic Energy was utilized.The proton beam was first transmitted through a 60.5μm aluminum foil and then impinged on a natural LiF target to produce neutron beam via^(7)Li(p,n)7Be reaction.The quasi-Gaussian energy distribution of protons in the LiF target resulted in neutron energy spectra that agreed with a Maxwellian energy distribution at kT=(22±2)keV,which was achieved by integrating neutrons detected within an emission angle of 65.0°±2.6°using a ^(6)Li glass detector positioned at 65°relative to the proton beam direction.The narrow angular spread of the Maxwelliandistributed neutron beam enables direct measurement of neutron capture cross-sections for most s-process nuclides,overcoming previous experimental limitations associated with broad angular distributions.展开更多
To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1...To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.展开更多
As oncologic therapies continue to advance,the overall survival of cancer patients has markedly increased.Nevertheless,virtually every anticancer treatment modality is accompanied by some degree of cardiotoxicity.Epid...As oncologic therapies continue to advance,the overall survival of cancer patients has markedly increased.Nevertheless,virtually every anticancer treatment modality is accompanied by some degree of cardiotoxicity.Epidemiological data indicate that approximately 30%of cancer survivors ultimately die from cardiovascular disease.Among the cardiotoxic agents,the anthracycline doxorubicin(DOX)is the most widely used.It effectively suppresses a variety of malignant tumors——including breast cancer,lymphoma,and acute leukemia——but its cardiac toxicity limits further escalation of clinical dosing.Literature reports identify a cumulative dose of≥250 mg/m²as the threshold of high risk,with roughly 25%of patients receiving DOX developing varying degrees of myocardial injury;severe cases progress to heart failure.Even at cumulative doses below the traditional safety limit,some patients exhibit cardiac dysfunction after the first administration,suggesting that cardiotoxicity is not solely a linear function of dose.DOX related cardiotoxicity can be classified as acute(hours to days after administration),sub acute(weeks to months),and chronic/late onset(years later).Most patients initially exhibit only mild reductions in left ventricular ejection fraction(LVEF)or subtle abnormalities in global longitudinal strain(GLS),often without symptoms.Recently,cardiac biomarkers(cTn,NT proBNP)combined with high sensitivity echocardiography(speckle tracking)have been recommended for monitoring high risk individuals,enabling detection of subclinical injury before overt LVEF decline.Currently,several preventive and therapeutic approaches are used in clinical practice,which can be summarized into the following four points.(1)Dose limitation and administration strategies:fractionated low dose regimens,liposomal encapsulation,or continuous infusion lower peak plasma concentrations,thereby reducing cardiac exposure.(2)Pharmacologic prophylaxis:βblockers(e.g.,carvedilol)and ACE inhibitors/ARBs have shown protective effects on LVEF in some randomized trials,though results remain inconsistent and require larger confirmatory studies.(3)Metabolic targeted interventions:animal experiments indicate that activation of PPARαor supplementation with L carnitine restores fatty acid oxidation and improves ATP generation,suggesting metabolic modulators as promising cardioprotective candidates.(4)Lifestyle modifications:regular aerobic exercise up regulates mitochondrial biogenesis genes(PGC-1α)and reduces reactive oxygen species(ROS)production;small clinical studies have demonstrated a potential benefit in attenuating cTnT elevation.However,DOX-induced cardiotoxicity has not been effectively controlled,indicating that the core mechanism underlying DOX‑related cardiac toxicity remains unidentified.Cardiomyocytes are high energy demand cells,and metabolic dysregulation is considered a central component of DOX induced cardiotoxicity.DOX disrupts myocardial metabolic balance through several interrelated pathways.(1)Oxidative stress and mitochondrial damage:DOX generates abundant ROS within cells,leading to mitochondrial membrane potential loss,lipid peroxidation,and iron accumulation,which suppress electron transport chain activity and markedly reduce ATP synthesis efficiency.(2)Autophagy dysregulation:DOX interferes with autophagic flux,preventing the clearance of damaged mitochondria and further aggravating apoptosis and inflammatory responses.(3)Inflammation and cytokine release:oxidative stress activates NF‑κB,up-regulating pro inflammatory cytokines such as TNF‑αand IL-6,creating a chronic inflammatory microenvironment that weakens myocardial contractility.(4)Epigenetic modifications:studies have shown that DOX alters DNA methylation and histone acetylation patterns in cardiomyocytes,affecting the expression of key metabolic genes(e.g.,PGC-1α,CPT-1)and further inhibiting fatty acidβoxidation.These mechanisms collectively lead to suppressed fatty acid oxidation and compensatory up regulation of glycolysis,manifested by an elevated lactate/pyruvate ratio,accumulation of medium chain acyl carnitines,and a pronounced decline in ATP production.The resulting energy deficit precipitates left ventricular contractile dysfunction and,ultimately,heart failure.Despite extensive basic and clinical research on DOX cardiotoxicity,a unified risk assessment model and precise interventions targeting metabolic disturbances remain lacking.This review systematically summarizes recent progress on DOX induced cardiotoxicity and highlights that impairment of myocardial energy metabolism is a central mechanism of injury,thereby deepened our understanding of how impaired myocardial energy metabolism drives DOX induced injury,we can move toward safer chemotherapy protocols that achieve“cure cancer without harming the heart”.展开更多
The ability to control the electrode interfaces in an electrochemical energy storage system is essential for achieving the desired electrochemical performance.However,achieving this ability requires an in-depth unders...The ability to control the electrode interfaces in an electrochemical energy storage system is essential for achieving the desired electrochemical performance.However,achieving this ability requires an in-depth understanding of the detailed interfacial nanostructures of the electrode under electrochemical operating conditions.In-situ transmission electron microscopy(TEM)is one of the most powerful techniques for revealing electrochemical energy storage mechanisms with high spatiotemporal resolution and high sensitivity in complex electrochemical environments.These attributes play a unique role in understanding how ion transport inside electrode nanomaterials and across interfaces under the dynamic conditions within working batteries.This review aims to gain an in-depth insight into the latest developments of in-situ TEM imaging techniques for probing the interfacial nanostructures of electrochemical energy storage systems,including atomic-scale structural imaging,strain field imaging,electron holography,and integrated differential phase contrast imaging.Significant examples will be described to highlight the fundamental understanding of atomic-scale and nanoscale mechanisms from employing state-of-the-art imaging techniques to visualize structural evolution,ionic valence state changes,and strain mapping,ion transport dynamics.The review concludes by providing a perspective discussion of future directions of the development and application of in-situ TEM techniques in the field of electrochemical energy storage systems.展开更多
This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The re...This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The region has substantial untapped potential in solar energy,wind energy,hydropower energy,as well as biomass and bioenergy,positioning it strategically for renewable energy deployment.The result demonstrated that integrating renewable energy can reduce greenhouse gas emissions,improve air quality,enhance energy security,and support rural development.Case studies from Kazakhstan,Uzbekistan,Kyrgyzstan,and Tajikistan showed measurable environmental and economic benefits.However,the large-scale use of renewable energy still faces numerous barriers,including outdated infrastructure,fragmented regulatory frameworks,limited investment,and shortages of technical expertise.Overcoming these obstacles requires institutional reform,stronger regional cooperation,and increasing engagement from international financial institutions and private investors.Modernizing grids,deploying storage systems,and investing in education,research,and innovation are critical for building human capacity in renewable energy sector.Accelerating the renewable energy transition is essential for Central Asia to meet climate goals,enhance environmental resilience,and ensure long-term socioeconomic development through innovation,investment,and regional collaboration.展开更多
In order to address environmental pollution and resource depletion caused by traditional power generation,this paper proposes an adaptive iterative dynamic-balance optimization algorithm that integrates the Improved D...In order to address environmental pollution and resource depletion caused by traditional power generation,this paper proposes an adaptive iterative dynamic-balance optimization algorithm that integrates the Improved Dung Beetle Optimizer(IDBO)with VariationalMode Decomposition(VMD).The IDBO-VMD method is designed to enhance the accuracy and efficiency of wind-speed time-series decomposition and to effectively smooth photovoltaic power fluctuations.This study innovatively improves the traditional variational mode decomposition(VMD)algorithm,and significantly improves the accuracy and adaptive ability of signal decomposition by IDBO selfoptimization of key parameters K and a.On this basis,Fourier transform technology is used to define the boundary point between high frequency and low frequency signals,and a targeted energy distribution strategy is proposed:high frequency fluctuations are allocated to supercapacitors to quickly respond to transient power fluctuations;Lowfrequency components are distributed to lead-carbon batteries,optimizing long-term energy storage and scheduling efficiency.This strategy effectively improves the response speed and stability of the energy storage system.The experimental results demonstrate that the IDBO-VMD algorithm markedly outperforms traditional methods in both decomposition accuracy and computational efficiency.Specifically,it effectively reduces the charge–discharge frequency of the battery,prolongs battery life,and optimizes the operating ranges of the state-of-charge(SOC)for both leadcarbon batteries and supercapacitors.In addition,the energy management strategy based on the algorithm not only improves the overall energy utilization efficiency of the system,but also shows excellent performance in the dynamic management and intelligent scheduling of renewable energy generation.展开更多
To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmenta...To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmental Lining,the inorganic retarder sodium pyrophosphate(TSPP)and three organic retarders were added to the A component:sodium citrate(SC),sodium tartrate(ST)and glycerol(GLY).The effect law and microscopic mechanism of viscosity,bleeding rate,setting time,gelling time,compressive strength,and stone rate were investigated.The results revealed that the addition of retarders could enhance the stability and setting time of the A component and increase the gelling time,stone rate,and compressive strength of two-component grout.Among them,the performance of the grout with an SC dosage of 0.1% was superior.The bleeding rate of this grout was reduced to 3.5%,the stone rate of the two-component grout was more than 99%,and the early compressive strength and late compressive strength of this grout were increased by approximately 35% and 7%,respectively.The initial and final setting time of the A component with a TSPP dosage of 0.3% was the longest,which was prolonged to 17 and 26 h,respectively.Microscopic analysis revealed that the four retarders hindered the hydration process of cement through complexation and adsorption,and inhibited the hydration of C_(3)S and the crystallisation of CH.Moreover,they reduced the defects caused by the rapid reaction of water glass and CH on the solid phase structure,enabled the microstructure of the stone body to be denser,and subsequently,enhanced the compressive strength.展开更多
Hydrogen energy development is transitioning from vision and plan-ning to widespread application.To date,more than 60 countries and regions have announced hydrogen energy development strategies focused on accelerating...Hydrogen energy development is transitioning from vision and plan-ning to widespread application.To date,more than 60 countries and regions have announced hydrogen energy development strategies focused on accelerating demonstration projects and real-world deployment.展开更多
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,...To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.展开更多
The pursuit of high energy density and sustainable energy storage devices has been the target of many researchers.However,safety issues such as the susceptibility of conventional liquid electrolytes to leakage and fla...The pursuit of high energy density and sustainable energy storage devices has been the target of many researchers.However,safety issues such as the susceptibility of conventional liquid electrolytes to leakage and flammability,as well as performance degradation due to uncontrollable dendrite growth in liquid electrolytes,have been limiting the further development of energy storage devices.In this regard,gel polymer electrolytes(GPEs)based on lignocellulosic(cellulose,hemicellulose,lignin)have attracted great interest due to their high thermal stability,excellent electrolyte wettability,and natural abundance.Therefore,in this critical review,a comprehensive overview of the current challenges faced by GPEs is presented,followed by a detailed description of the opportunities and advantages of lignocellulosic materials for the fabrication of GPEs for energy storage devices.Notably,the key properties and corresponding construction strategies of GPEs for energy storage are analyzed and discussed from the perspective of lignocellulose for the first time.Moreover,the future challenges and prospects of lignocellulose-mediated GPEs in energy storage applications are also critically reviewed and discussed.We sincerely hope this review will stimulate further research on lignocellulose-mediated GPEs in energy storage and provide meaningful directions for the strategy of designing advanced GPEs.展开更多
In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of...In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of pure aluminum particles to mitigate agglomeration and enhance the combustion efficiency of solid propellants(Combustion efficiency herein refers to the completeness of metallic fuel oxidation,quantified as the ratio of actual-to-theoretical energy released during combustion)with high Al content and low burning rates.The impact of Al-Li alloy with different Li contents on combustion and agglomeration of solid propellant was investigated using explosion heat,combustion heat,differential thermal analysis(DTA),thermos-gravimetric analysis(TG),dynamic high-pressure combustion test,ignition experiment of small solid rocket motor(SRM)tests,condensation combustion product collection,and X-ray diffraction techniques(XRD).Compared with pure Al,Al-Li alloys exhibit higher combustion heat,which contributes to improved combustion efficiency in Al-Li alloy-containing propellants.DTA and TG analyses demonstrated higher reactivity and lower ignition temperatures for Al-Li alloys.High-pressure combustion experiments at 5 MPa showed that Al-Li alloy fuel significantly decreases combustion agglomeration.The results from theφ75 mm andφ165 mm SRM and XRD tests further support this finding.This study provides novel insights into the combustion and agglomeration behaviors of high-Al,low-burning-rate composite solid propellants and supports the potential application of Al-Li alloys in advanced propellant formulations.展开更多
Electrical and electronic devices face significant challenges in heatmanagement due to their compact size and high heat flux,which negatively impact performance and reliability.Conventional coolingmethods,such as forc...Electrical and electronic devices face significant challenges in heatmanagement due to their compact size and high heat flux,which negatively impact performance and reliability.Conventional coolingmethods,such as forced air cooling,often struggle to transfer heat efficiently.In contrast,thermoelectric coolers(TECs)provide an innovative active cooling solution to meet growing thermal management demands.In this research,a refrigerant based on mono ethylene glycol and distilled water was used instead of using gases,in addition to using thermoelectric cooling units instead of using a compressor in traditional refrigeration systems.This study evaluates the performance of a Peltierbased thermalmanagement systemby analyzing the effects of using two,three,and four Peltiermodules on cooling rates,power consumption,temperature reduction,and system efficiency.Experimental results indicate that increasing the number of Peltier modules significantly enhances cooling performance.The four-module system achieved an optimal balance between cooling speed and energy efficiency,reducing the temperature of a liquidmixture(30% mono ethylene glycol+70% distilled water plus laser dyes)to 8℃ in just 17 min.It demonstrated a cooling rate of 0.794℃/min and a high coefficient of performance(COP)of 1.2 while consuming less energy than the two-and three-module systems.Furthermore,the study revealed that increasing the number of modules led to faster air cooling and improved temperature reduction.These findings highlight the importance of selecting the optimal number of Peltier modules to enhance efficiency and cooling speed whileminimizing energy consumption.This makes TEC technology a sustainable and effective solution for applications requiring rapid and reliable thermal management.展开更多
Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or ...Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.展开更多
文摘An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 60231010, 60471008, and 60571003） and the National Center for Nanoscience and Technology of China.
文摘The low-energy electron point source （LEEPS） microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes （MWCNTs） synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 10^4 was obtained. The resolution of the acquired images is -10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.
基金financially supported by the National Natural Science Foundation of China(Nos.52274315 and 52374320)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-22-011A1 and FRF-DF22-16)。
文摘During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.
文摘The description and function characterization of a flange-on type low energy electron mi- croscope are given. In this microscope a magnetic beam separator with 10° deflection angle is used in order to facilitate compacting the instrument on a single 10 in. flange. Mean- while some correcting elements in the electron optical system are simplified to reduce the complexities of construction and operation. The sample is set close to ground potential, so that all the electrostatic lenses are easily to float at high voltages. The performance of the microscope in typical low energy electron microscopy, low energy electron diffraction and photoemission electron microscopy modes is demonstrated through several experiments. A lateral resolution of 51 nm is estimated for low energy electron microscopy imaging. With femtosecond laser as light source, the consequent nonlinear photoemission makes this micro-scope also suitable for the observation of optical near field phenomena and a lateral resolution of 110 nm is obtained.
基金Supported by Major Project of School-level Teaching Reform and Research of Guangxi University of Chinese Medicine(2022A006)。
文摘In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.
文摘Cameroon’s capital Yaoundécame alive on 16 and 17 July as it hosted a major international gathering for the liquefied natural gas(LNG)sector.The event brought together over 1,000 industry professionals and 50 exhibitors from more than 30 countries including China to address the future of cleaner and more inclusive energy.
基金National Natural Science Foundation of China(12125509,11961141003,12275361,U2267205,12175152,12175121)National Key Research and Development Project(2022YFA1602301)Continuous-support Basic Scientific Research Project。
文摘To generate a neutron beam exhibiting a Maxwellian energy distribution with narrow emission angles for measuring the neutron capture reaction rates of the s-process nuclides,a monoenergetic 3.4 MeV proton beam produced by the tandem-accelerator in the China Institute of Atomic Energy was utilized.The proton beam was first transmitted through a 60.5μm aluminum foil and then impinged on a natural LiF target to produce neutron beam via^(7)Li(p,n)7Be reaction.The quasi-Gaussian energy distribution of protons in the LiF target resulted in neutron energy spectra that agreed with a Maxwellian energy distribution at kT=(22±2)keV,which was achieved by integrating neutrons detected within an emission angle of 65.0°±2.6°using a ^(6)Li glass detector positioned at 65°relative to the proton beam direction.The narrow angular spread of the Maxwelliandistributed neutron beam enables direct measurement of neutron capture cross-sections for most s-process nuclides,overcoming previous experimental limitations associated with broad angular distributions.
基金supported by the National Natural Science Foundation of China(Grant Nos.52274339,52174321,52074186,and 52104337)Natural Science Foundation of Jiangsu Province(Grant No.BK20231317)China Baowu Low-Carbon Metallurgy Innovation Fund(Grant No.BWLCF202108).
文摘To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.
基金supported by grants from the Applied Basic Research Foundation of Yunnan Province(202301AT070095)the Candidate Talents Training Fund of Yunnan Province(H-2024069)。
文摘As oncologic therapies continue to advance,the overall survival of cancer patients has markedly increased.Nevertheless,virtually every anticancer treatment modality is accompanied by some degree of cardiotoxicity.Epidemiological data indicate that approximately 30%of cancer survivors ultimately die from cardiovascular disease.Among the cardiotoxic agents,the anthracycline doxorubicin(DOX)is the most widely used.It effectively suppresses a variety of malignant tumors——including breast cancer,lymphoma,and acute leukemia——but its cardiac toxicity limits further escalation of clinical dosing.Literature reports identify a cumulative dose of≥250 mg/m²as the threshold of high risk,with roughly 25%of patients receiving DOX developing varying degrees of myocardial injury;severe cases progress to heart failure.Even at cumulative doses below the traditional safety limit,some patients exhibit cardiac dysfunction after the first administration,suggesting that cardiotoxicity is not solely a linear function of dose.DOX related cardiotoxicity can be classified as acute(hours to days after administration),sub acute(weeks to months),and chronic/late onset(years later).Most patients initially exhibit only mild reductions in left ventricular ejection fraction(LVEF)or subtle abnormalities in global longitudinal strain(GLS),often without symptoms.Recently,cardiac biomarkers(cTn,NT proBNP)combined with high sensitivity echocardiography(speckle tracking)have been recommended for monitoring high risk individuals,enabling detection of subclinical injury before overt LVEF decline.Currently,several preventive and therapeutic approaches are used in clinical practice,which can be summarized into the following four points.(1)Dose limitation and administration strategies:fractionated low dose regimens,liposomal encapsulation,or continuous infusion lower peak plasma concentrations,thereby reducing cardiac exposure.(2)Pharmacologic prophylaxis:βblockers(e.g.,carvedilol)and ACE inhibitors/ARBs have shown protective effects on LVEF in some randomized trials,though results remain inconsistent and require larger confirmatory studies.(3)Metabolic targeted interventions:animal experiments indicate that activation of PPARαor supplementation with L carnitine restores fatty acid oxidation and improves ATP generation,suggesting metabolic modulators as promising cardioprotective candidates.(4)Lifestyle modifications:regular aerobic exercise up regulates mitochondrial biogenesis genes(PGC-1α)and reduces reactive oxygen species(ROS)production;small clinical studies have demonstrated a potential benefit in attenuating cTnT elevation.However,DOX-induced cardiotoxicity has not been effectively controlled,indicating that the core mechanism underlying DOX‑related cardiac toxicity remains unidentified.Cardiomyocytes are high energy demand cells,and metabolic dysregulation is considered a central component of DOX induced cardiotoxicity.DOX disrupts myocardial metabolic balance through several interrelated pathways.(1)Oxidative stress and mitochondrial damage:DOX generates abundant ROS within cells,leading to mitochondrial membrane potential loss,lipid peroxidation,and iron accumulation,which suppress electron transport chain activity and markedly reduce ATP synthesis efficiency.(2)Autophagy dysregulation:DOX interferes with autophagic flux,preventing the clearance of damaged mitochondria and further aggravating apoptosis and inflammatory responses.(3)Inflammation and cytokine release:oxidative stress activates NF‑κB,up-regulating pro inflammatory cytokines such as TNF‑αand IL-6,creating a chronic inflammatory microenvironment that weakens myocardial contractility.(4)Epigenetic modifications:studies have shown that DOX alters DNA methylation and histone acetylation patterns in cardiomyocytes,affecting the expression of key metabolic genes(e.g.,PGC-1α,CPT-1)and further inhibiting fatty acidβoxidation.These mechanisms collectively lead to suppressed fatty acid oxidation and compensatory up regulation of glycolysis,manifested by an elevated lactate/pyruvate ratio,accumulation of medium chain acyl carnitines,and a pronounced decline in ATP production.The resulting energy deficit precipitates left ventricular contractile dysfunction and,ultimately,heart failure.Despite extensive basic and clinical research on DOX cardiotoxicity,a unified risk assessment model and precise interventions targeting metabolic disturbances remain lacking.This review systematically summarizes recent progress on DOX induced cardiotoxicity and highlights that impairment of myocardial energy metabolism is a central mechanism of injury,thereby deepened our understanding of how impaired myocardial energy metabolism drives DOX induced injury,we can move toward safer chemotherapy protocols that achieve“cure cancer without harming the heart”.
基金supported by the National Key Research Program of China under Grant No.2024YFA1408000the National Natural Science Foundation of China(52231007,12327804,T2321003,22088101)+1 种基金in part by the National Key Research Program of China under Grant 2021YFA1200600the support from the U.S.National Science Foundation(CHE 2102482)。
文摘The ability to control the electrode interfaces in an electrochemical energy storage system is essential for achieving the desired electrochemical performance.However,achieving this ability requires an in-depth understanding of the detailed interfacial nanostructures of the electrode under electrochemical operating conditions.In-situ transmission electron microscopy(TEM)is one of the most powerful techniques for revealing electrochemical energy storage mechanisms with high spatiotemporal resolution and high sensitivity in complex electrochemical environments.These attributes play a unique role in understanding how ion transport inside electrode nanomaterials and across interfaces under the dynamic conditions within working batteries.This review aims to gain an in-depth insight into the latest developments of in-situ TEM imaging techniques for probing the interfacial nanostructures of electrochemical energy storage systems,including atomic-scale structural imaging,strain field imaging,electron holography,and integrated differential phase contrast imaging.Significant examples will be described to highlight the fundamental understanding of atomic-scale and nanoscale mechanisms from employing state-of-the-art imaging techniques to visualize structural evolution,ionic valence state changes,and strain mapping,ion transport dynamics.The review concludes by providing a perspective discussion of future directions of the development and application of in-situ TEM techniques in the field of electrochemical energy storage systems.
文摘This study examined the role of green energy development in mitigating climate change and fostering sustainable development in Central Asia including Kazakhstan,Uzbekistan,Kyrgyzstan,Tajikistan,and Turkmenistan.The region has substantial untapped potential in solar energy,wind energy,hydropower energy,as well as biomass and bioenergy,positioning it strategically for renewable energy deployment.The result demonstrated that integrating renewable energy can reduce greenhouse gas emissions,improve air quality,enhance energy security,and support rural development.Case studies from Kazakhstan,Uzbekistan,Kyrgyzstan,and Tajikistan showed measurable environmental and economic benefits.However,the large-scale use of renewable energy still faces numerous barriers,including outdated infrastructure,fragmented regulatory frameworks,limited investment,and shortages of technical expertise.Overcoming these obstacles requires institutional reform,stronger regional cooperation,and increasing engagement from international financial institutions and private investors.Modernizing grids,deploying storage systems,and investing in education,research,and innovation are critical for building human capacity in renewable energy sector.Accelerating the renewable energy transition is essential for Central Asia to meet climate goals,enhance environmental resilience,and ensure long-term socioeconomic development through innovation,investment,and regional collaboration.
基金funded by the Institute of Smart Energy,Huaiyin Institute of Technology,under Grant No.HIT-ISE-2024-07.
文摘In order to address environmental pollution and resource depletion caused by traditional power generation,this paper proposes an adaptive iterative dynamic-balance optimization algorithm that integrates the Improved Dung Beetle Optimizer(IDBO)with VariationalMode Decomposition(VMD).The IDBO-VMD method is designed to enhance the accuracy and efficiency of wind-speed time-series decomposition and to effectively smooth photovoltaic power fluctuations.This study innovatively improves the traditional variational mode decomposition(VMD)algorithm,and significantly improves the accuracy and adaptive ability of signal decomposition by IDBO selfoptimization of key parameters K and a.On this basis,Fourier transform technology is used to define the boundary point between high frequency and low frequency signals,and a targeted energy distribution strategy is proposed:high frequency fluctuations are allocated to supercapacitors to quickly respond to transient power fluctuations;Lowfrequency components are distributed to lead-carbon batteries,optimizing long-term energy storage and scheduling efficiency.This strategy effectively improves the response speed and stability of the energy storage system.The experimental results demonstrate that the IDBO-VMD algorithm markedly outperforms traditional methods in both decomposition accuracy and computational efficiency.Specifically,it effectively reduces the charge–discharge frequency of the battery,prolongs battery life,and optimizes the operating ranges of the state-of-charge(SOC)for both leadcarbon batteries and supercapacitors.In addition,the energy management strategy based on the algorithm not only improves the overall energy utilization efficiency of the system,but also shows excellent performance in the dynamic management and intelligent scheduling of renewable energy generation.
基金Funded by the National Natural Science Foundation of China(No.52378394)the Fundamental Research Funds for the Central Universities(No.B230201037)。
文摘To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmental Lining,the inorganic retarder sodium pyrophosphate(TSPP)and three organic retarders were added to the A component:sodium citrate(SC),sodium tartrate(ST)and glycerol(GLY).The effect law and microscopic mechanism of viscosity,bleeding rate,setting time,gelling time,compressive strength,and stone rate were investigated.The results revealed that the addition of retarders could enhance the stability and setting time of the A component and increase the gelling time,stone rate,and compressive strength of two-component grout.Among them,the performance of the grout with an SC dosage of 0.1% was superior.The bleeding rate of this grout was reduced to 3.5%,the stone rate of the two-component grout was more than 99%,and the early compressive strength and late compressive strength of this grout were increased by approximately 35% and 7%,respectively.The initial and final setting time of the A component with a TSPP dosage of 0.3% was the longest,which was prolonged to 17 and 26 h,respectively.Microscopic analysis revealed that the four retarders hindered the hydration process of cement through complexation and adsorption,and inhibited the hydration of C_(3)S and the crystallisation of CH.Moreover,they reduced the defects caused by the rapid reaction of water glass and CH on the solid phase structure,enabled the microstructure of the stone body to be denser,and subsequently,enhanced the compressive strength.
文摘Hydrogen energy development is transitioning from vision and plan-ning to widespread application.To date,more than 60 countries and regions have announced hydrogen energy development strategies focused on accelerating demonstration projects and real-world deployment.
基金support from the National Natural Science Foundation of China(Grant Nos.42107193,42077245)supported by the Sichuan Science and Technology Program(2025YFNH0008,2025YFNH0004)+1 种基金the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2023Z006)the Everest Scientific Research Program 2.0:Research on mechanism and control of glacial lake outburst chain catastrophe in Qinghai-Xizang Plateau based on man-earth coordination perspective.
文摘To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.
基金supported by the National Natural Science Foundation of China(32501592,32271814,32301530,32471806)Young Elite Scientist Sponsorship Program by Cast(No.YESS20230242)+3 种基金Natural Science Foundation of Tianjin(23JCZDJC00630,24JCZDJC00630)the China Postdoctoral Science Foundation(2023M740563)Tianjin Enterprise Technology Commissioner Project(25YDTPJC00690)China Scholarship Council(202408120091,202408120105).
文摘The pursuit of high energy density and sustainable energy storage devices has been the target of many researchers.However,safety issues such as the susceptibility of conventional liquid electrolytes to leakage and flammability,as well as performance degradation due to uncontrollable dendrite growth in liquid electrolytes,have been limiting the further development of energy storage devices.In this regard,gel polymer electrolytes(GPEs)based on lignocellulosic(cellulose,hemicellulose,lignin)have attracted great interest due to their high thermal stability,excellent electrolyte wettability,and natural abundance.Therefore,in this critical review,a comprehensive overview of the current challenges faced by GPEs is presented,followed by a detailed description of the opportunities and advantages of lignocellulosic materials for the fabrication of GPEs for energy storage devices.Notably,the key properties and corresponding construction strategies of GPEs for energy storage are analyzed and discussed from the perspective of lignocellulose for the first time.Moreover,the future challenges and prospects of lignocellulose-mediated GPEs in energy storage applications are also critically reviewed and discussed.We sincerely hope this review will stimulate further research on lignocellulose-mediated GPEs in energy storage and provide meaningful directions for the strategy of designing advanced GPEs.
基金the National Natural Science Foundation of China(Grant No.U2441263)for financial support of this work。
文摘In composite solid propellants with high aluminum(Al)content and low burning rate,incomplete combustion of the Al powder may occur.In this study,varying lithium(Li)content in Al-Li alloy powder was utilized instead of pure aluminum particles to mitigate agglomeration and enhance the combustion efficiency of solid propellants(Combustion efficiency herein refers to the completeness of metallic fuel oxidation,quantified as the ratio of actual-to-theoretical energy released during combustion)with high Al content and low burning rates.The impact of Al-Li alloy with different Li contents on combustion and agglomeration of solid propellant was investigated using explosion heat,combustion heat,differential thermal analysis(DTA),thermos-gravimetric analysis(TG),dynamic high-pressure combustion test,ignition experiment of small solid rocket motor(SRM)tests,condensation combustion product collection,and X-ray diffraction techniques(XRD).Compared with pure Al,Al-Li alloys exhibit higher combustion heat,which contributes to improved combustion efficiency in Al-Li alloy-containing propellants.DTA and TG analyses demonstrated higher reactivity and lower ignition temperatures for Al-Li alloys.High-pressure combustion experiments at 5 MPa showed that Al-Li alloy fuel significantly decreases combustion agglomeration.The results from theφ75 mm andφ165 mm SRM and XRD tests further support this finding.This study provides novel insights into the combustion and agglomeration behaviors of high-Al,low-burning-rate composite solid propellants and supports the potential application of Al-Li alloys in advanced propellant formulations.
文摘Electrical and electronic devices face significant challenges in heatmanagement due to their compact size and high heat flux,which negatively impact performance and reliability.Conventional coolingmethods,such as forced air cooling,often struggle to transfer heat efficiently.In contrast,thermoelectric coolers(TECs)provide an innovative active cooling solution to meet growing thermal management demands.In this research,a refrigerant based on mono ethylene glycol and distilled water was used instead of using gases,in addition to using thermoelectric cooling units instead of using a compressor in traditional refrigeration systems.This study evaluates the performance of a Peltierbased thermalmanagement systemby analyzing the effects of using two,three,and four Peltiermodules on cooling rates,power consumption,temperature reduction,and system efficiency.Experimental results indicate that increasing the number of Peltier modules significantly enhances cooling performance.The four-module system achieved an optimal balance between cooling speed and energy efficiency,reducing the temperature of a liquidmixture(30% mono ethylene glycol+70% distilled water plus laser dyes)to 8℃ in just 17 min.It demonstrated a cooling rate of 0.794℃/min and a high coefficient of performance(COP)of 1.2 while consuming less energy than the two-and three-module systems.Furthermore,the study revealed that increasing the number of modules led to faster air cooling and improved temperature reduction.These findings highlight the importance of selecting the optimal number of Peltier modules to enhance efficiency and cooling speed whileminimizing energy consumption.This makes TEC technology a sustainable and effective solution for applications requiring rapid and reliable thermal management.
文摘Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
