A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetrae...A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.展开更多
The precipitation of secondary Laves phases and its effect on notch sensitivity are systematically studied in Thermo-Span alloy. The results show that the precipitation peak temperature of secondary Laves phases is 9...The precipitation of secondary Laves phases and its effect on notch sensitivity are systematically studied in Thermo-Span alloy. The results show that the precipitation peak temperature of secondary Laves phases is 925 ℃. Below 925 ℃, the volume fraction of secondary Laves phases increases with the rise of the temperature, and its morphology changes from granular to thin-film;above 925 ℃, the volume fraction of secondary Laves phases shows an opposite trend to temperature, and its morphology changes from thin-film to granular. A detailed explanation through linear density (ρ) is provided that the influence of secondary Laves phases at the grain boundaries (GBs) on notch sensitivity depends on the coupling competition effect of their size, quantity, and morphology. Notably, the granular Laves phases are more beneficial to improving the notch sensitivity of the alloy compared with thin-film Laves phases. Granular secondary Laves phases can promote the formation of γ′ phases depletion zone to improve the ability of GBs to accommodate high strain localization, and effectively inhibit the crack initiation and propagation.展开更多
Elemental modulation and heat treatment optimization have emerged as pivotal strategies for enhancing the soft magnetic properties of alloys.We thoroughly examine the impact of microalloyed Co on the amorphous formati...Elemental modulation and heat treatment optimization have emerged as pivotal strategies for enhancing the soft magnetic properties of alloys.We thoroughly examine the impact of microalloyed Co on the amorphous formation ability,thermal stability,and soft magnetic properties of Fe_(80)Co_(x)Si_(7-x)B_(8)P_(4)Cu1(x=0,0.5,1,1.5,2)alloys.The influence of different annealing processes on these properties is analyzed through detailed insights into the evolution of nanocrystalline microstructure and magnetic domain behavior.Our findings indicate that Co addition facilitates the nucleation and growth of the a-Fe(Si,Co)phase while broadening the thermal processing window,thereby significantly improving the alloy’s soft magnetic properties.Notably,the alloy with x=1 undergoes a pre-annealing and reheating process to yield a finer,denser,and more uniform nanocrystalline structure(average grain size D=20.29 nm,grain density Nd=1.5×10^(23)m^(-3)).This refinement enables the formation of broad magnetic domains characterized by 180°domain walls,culminating in exceptional soft magnetic properties,including a high magnetic flux density(B_(s)=1.81 T),high effective permeability(μ_(e)=18,014),and low coercivity(H_(c)=5.57 A m^(-1)).Further,the pinning fields(Hp)for the x=1 alloy are notably low,ranging from15 to 20 A m^(-1),while the maximum effective permeability reaches 69,300.These exceptional properties are directly linked to the alloy’s minimized total free energy(E)and its highly homogeneous microstructure,which collectively suppress magnetic pinning effects.Such characteristics position the x=1 alloy as an exceptional candidate for high-sensitivity applications,particularly in sensor device systems functioning under mild magnetic fields and necessitating swift reaction.展开更多
Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycl...Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycling stability and reaction kinetics.To address these challenges,we designed a core–shell heterostructure(VONC-T,T represents temperature)composed of a VN core and a porous carbon shell.This structure was synthesized via in-situ construction,involving optimized ratio of coating a zinc-based zeolitic imidazolate framework(ZIF-8)onto a vanadium-based metal-organic framework(MIL-47(V)),followed by a thermal treatment.This process ensures a high degree of interfacial stability between the core and shell,effectively mitigating the structural variation of VN during irreversible phase transitions and enhancing the overall structural stability.During thermal driving,the volatilization of zinc within the shell layer created a porous channel effect,which facilitating Zn^(2+)diffusion.The enhancement of Zn²⁺diffusion strengthens the efficient conversion of VN to amorphous VOx,labeled as VONC-T-a,which provides more active sites and consequently results in a high specific capacity.The optimized heterostructure of VONC-900-a presented high reversible capacity of 387.2 mAh g^(−1)at 0.2 A g^(−1)and demonstrated excellent rate performance,achieving 274.5 mAh g^(−1)at 20 A g^(−1),while maintaining a capacity retention rate of 93.3%after 5000 cycles at 10 A g^(−1).Density functional theory calculations confirmed improved reaction kinetics in the core–shell structure.This study not only highlights the potential of amorphous vanadium oxide core–shell heterostructure for AZIBs but also provides new insights into the conversion mechanisms of VN.展开更多
Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were...Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were designed and prepared.Close bomb tests and semi-confined bomb experiments were used to investigate the burning and erosion properties of the propellants.The mechanism of erosion-reducing of titanium dioxide(titania,TiO_(2)),talc,and octaphenylsilsesquioxane(OPS)on the propellant was comparatively analyzed.The results show that OPS has the lowest burning rate and the longest burning time,and a minimized loss of fire force,with the best effect of explosion heat reduction.The erosion reduction efficiency of OPS is twice that of TiO_(2) and talc.The mechanism analysis shows that the decomposition and heat absorption of OPS can effectively reduce the thermal erosion effect and carbon erosion,and the gas produced can reduce the loss of chamber pressure and form a uniformly distributed nano-SiO_(2) protective layer.This solid-state high-efficiency organosilicon erosion inhibitor is an important guide for designing high-energy low-erosion gun propellants.展开更多
A dynamic model of a flexible rotor supported by ball bearings with rubber damping rings was proposed by combining the finite element and the mass-centralized method.In the proposed model,the rotor was built with the ...A dynamic model of a flexible rotor supported by ball bearings with rubber damping rings was proposed by combining the finite element and the mass-centralized method.In the proposed model,the rotor was built with the Timoshenko beam element,while the supports and bearing outer rings were modelled by the mass-centralized method.Meanwhile,the influences of the rotor’s gravity,unbalanced force and nonlinear bearing force were considered.The governing equations were solved by precise integration and the Runge-Kutta hybrid numerical algorithm.To verify the correctness of the modelling method,theoretical and experimental analysis is carried out by a rotor-bearing test platform,where the error rate between the theoretical and experimental studies is less than 10%.Besides that,the influence of the rubber damping ring on the dynamic properties of the rotor-bearing coupling system is also analyzed.The conclusions obtained are in agreement with the real-world deployment.On this basis,the bifurcation and chaos behaviors of the coupling system were carried out with rotational speed and rubber damping ring’s stiffness.The results reveal that as rotational speed increases,the system enters into chaos by routes of crisis,quasi-periodic and intermittent bifurcation.However,the paths of crisis,quasi-periodic bifurcation,and Hopf bifurcation to chaos were detected under the parameter of rubber damping ring’s stiffness.Additionally,the bearing gap affects the rotor system’s dynamic characteristics.Moreover,the excessive bearing gap will make the system’s periodic motion change into chaos,and the rubber damping ring’s stiffness has a substantial impact on the system motion.展开更多
With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical...With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.展开更多
Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topogra...Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales. In this research, periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability. This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers, including polyvinyl chloride(PVC), polyethylene 1000(PE1000), polypropylene copolymer(PP) and polytetrafluoroethylene(PFTE), which cannot be processed by conventional semiconductor-based manufacturing processes. Materials exhibiting common wettability properties(θ≈ 90°) changed to exhibit "superhydrophobic" behavior(θ > 150°). Compared with the size of the structures, the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability.展开更多
Six new transition metal complexes, [Zn（HBTC）（PYTPY）]n·n PYTPY（1）, [Cu（HBTC）（PYTPY）]n·n PYTPY（2）, [Co（HBTC）（PYTPY）]n·n DMF（3）, [Mn（HBTC）（PYTPY）]n·n DMF（4）, [Cd（HBTC）（PYTP...Six new transition metal complexes, [Zn（HBTC）（PYTPY）]n·n PYTPY（1）, [Cu（HBTC）（PYTPY）]n·n PYTPY（2）, [Co（HBTC）（PYTPY）]n·n DMF（3）, [Mn（HBTC）（PYTPY）]n·n DMF（4）, [Cd（HBTC）（PYTPY）（H2O）]n·2nH2O（5）, and [Co（HBTC）（PYTPY）（H2O）2]（6）,（H3BTC = 1,3,5-benzenetricarboxylic acid, PYTPY = 4＇-（4-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, DMF = N,N？-dimethylformamide）, have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complexes 1~5 all feature one-dimensional chain structures, and complex 6 exhibits a zero-dimensional structure. Complexes 1~5 present three-dimensional（3D） supramolecular frameworks via π-π stacking interactions, whenas 6 has also a 3D supramolecular structure assembled by hydrogen bonding. Meanwhile, complexes 1 ~ 6 exhibit the thermal stabilities and photoluminescent properties.展开更多
While the rechargeable aqueous zinc-ion batteries(AZIBs)have been recognized as one of the most viable batteries for scale-up application,the instability on Zn anode–electrolyte interface bottleneck the further devel...While the rechargeable aqueous zinc-ion batteries(AZIBs)have been recognized as one of the most viable batteries for scale-up application,the instability on Zn anode–electrolyte interface bottleneck the further development dramatically.Herein,we utilize the amino acid glycine(Gly)as an electrolyte additive to stabilize the Zn anode–electrolyte interface.The unique interfacial chemistry is facilitated by the synergistic“anchor-capture”effect of polar groups in Gly molecule,manifested by simultaneously coupling the amino to anchor on the surface of Zn anode and the carboxyl to capture Zn^(2+)in the local region.As such,this robust anode–electrolyte interface inhibits the disordered migration of Zn^(2+),and effectively suppresses both side reactions and dendrite growth.The reversibility of Zn anode achieves a significant improvement with an average Coulombic efficiency of 99.22%at 1 mA cm^(−2)and 0.5 mAh cm^(−2)over 500 cycles.Even at a high Zn utilization rate(depth of discharge,DODZn)of 68%,a steady cycle life up to 200 h is obtained for ultrathin Zn foils(20μm).The superior rate capability and long-term cycle stability of Zn–MnO_(2)full cells further prove the effectiveness of Gly in stabilizing Zn anode.This work sheds light on additive designing from the specific roles of polar groups for AZIBs.展开更多
To control the power hierarchy design of lithium-ion battery(LIB)builtup sets for electric vehicles(EVs),we offer intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulate...To control the power hierarchy design of lithium-ion battery(LIB)builtup sets for electric vehicles(EVs),we offer intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulated in full-scale LIB built-up models.As primary structural tectonics,heterogeneous composite superstructures of full-cell-LIB(anode//cathode)electrodes were designed in closely packed flower agave rosettes TiO2@C(FRTO@C anode)and vertical-star-tower LiFePO4@C(VST@C cathode)building blocks to regulate the electron/ion movement in the three-dimensional axes and orientation pathways.The superpower hierarchy surfaces and multi-directional orientation components may create isosurface potential electrodes with mobile electron movements,in-to-out interplay electron dominances,and electron/charge cloud distributions.This study is the first to evaluate the hotkeys of choice anode/cathode architectonics to assemble different LIB-electrode platforms with high-mobility electron/ion flows and high-performance capacity functionalities.Density functional theory calculation revealed that the FRTO@C anode and VST-(i)@C cathode architectonics are a superior choice for the configuration of full-scale LIB built-up models.The integrated FRTO@C//VST-(i)@C full-scale LIB retains a huge discharge capacity(~94.2%),an average Coulombic efficiency of 99.85%after 2000 cycles at 1 C,and a high energy density of 127 Wh kg?1,thereby satisfying scale-up commercial EV requirements.展开更多
AIM:To assess the biosafety of a poly(acrylamide-cosodium acrylate)hydrogel(PAH)as a 3D-printed intraocular lens(IOL)material.METHODS:The biosafety of PAH was first evaluated in vitro using human lens epithelial cells...AIM:To assess the biosafety of a poly(acrylamide-cosodium acrylate)hydrogel(PAH)as a 3D-printed intraocular lens(IOL)material.METHODS:The biosafety of PAH was first evaluated in vitro using human lens epithelial cells(LECs)and the ARPE19 cell line,and a cell counting kit-8(CCK-8)assay was performed to investigate alterations in cell proliferation.A thin film of PAH and a conventional IOL were intraocularly implanted into the eyes of New Zealand white rabbits respectively,and a sham surgery served as control group.The anterior segment photographs,intraocular pressure(IOP),blood parameters and electroretinograms(ERG)were recorded.Inflammatory cytokines in the aqueous humor,such as TNFαand IL-8,were examined by ELISA.Cell apoptosis of the retina was investigated by TUNEL assay,and macro PAHge activation was detected by immunostaining.RESULTS:PAH did not slow cell proliferation when cocultured with human LECs or ARPE19 cells.The implantation of a thin film of a 3 D-printed IOL composed of PAH did not affect the IOP,blood parameters,ERG or optical structure in any of the three experimental groups(n=3 for each).Both TNFαand IL-8 in the aqueous humor of PAH group were transiently elevated 1 wk post-operation and recovered to normal levels at 1 and 3 mo post-operation.Iba1+macroPAHges in the anterior chamber angle in PAH group were increased markedly compared to those of the control group;however,there was no significant difference compared to those in the IOL group.CONCLUSION:PAH is a safe material for 3D printing of personal IOLs that hold great potential for future clinical applications.展开更多
In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasi...In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasing interest.In this work,a kind of core-shell structured microcapsule was synthesized by an in-situ polymerization,where paraffin was used as the core,while methanol was applied to mod-ify the melamine-formaldehyde shell to reduce toxicity and improve thermal stability.Moreover,three different types of heat conductive fillers with the same content of 10 wt.%,i.e.,nano-Al_(2)O_(3),nano-ZnO and carbon nanotubes were added,generating composites.The microcapsules were uniform,and were not affected by the thermal fillers,which were evenly dispersed around.The composite sample with carbon nanotubes(10 wt.%)showed the highest thermal conductivity of 0.50 W/(m K)and latent heat of 139.64 J/g.Furthermore,according to the leakage testing and battery charge/discharge experiments,compared with Al_(2)O_(3)and ZnO,the addition of carbon nanotubes remarkably enhances the heat storage ability as latent heat from 126.98 J/g for the prepared sample with Al_(2)O_(3)and 125.86 J/g for the one with ZnO,then to 139.64 J/g,as well as dissipation performance as a cooling effect by decreasing the sur-face temperature of battery from 2%to 12%of microcapsule,composite sample with carbon nanotubes presents a broad application prospect in battery thermal management system and energy storage field.展开更多
Calcium(Ca)and neodymium(Nd)were introduced in the AZ61 alloy as alloying elements.The microstructure,corrosion behavior,and discharge properties of AZ61-1Nd-xCa(x=0,0.5 wt.%,1 wt.%,2 wt.%)alloys as anodes for Mg-air ...Calcium(Ca)and neodymium(Nd)were introduced in the AZ61 alloy as alloying elements.The microstructure,corrosion behavior,and discharge properties of AZ61-1Nd-xCa(x=0,0.5 wt.%,1 wt.%,2 wt.%)alloys as anodes for Mg-air batteries were systematically investigated.The results indicated that the AZ61-1Nd-1Ca alloy exhibits the best corrosion resistance during electrochemical experiments and hydrogen evolution tests.Discharge performance tests showed that the AZ61-1Nd-1Ca alloy exhibits the best specific capacity(1193.6 mAh g^(-1)),energy density(1893.7 mWh g^(-1)),anode efficiency(60.3%),and cell voltage(1.246 V)at higher current densities.This is mainly attributed to the addition of Ca element,which refines the grain size of the alloy and increases the grain boundary area.In addition,Al_(2)Nd and Al_(2)Ca phases have similar corrosion mechanisms in the cross-section of the extruded alloy.The precipitated granular Al_(2)Ca phase is uniformly dispersed on the substrate and acts as a physical barrier.This not only enhances the corrosion resistance of the alloy but also improves the anode efficiency of the alloy during discharge.展开更多
Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found ap...Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found applications in numerous fields. The stiff and fragile structure of monolithic polymers leads to the innate cracks to cause fracture and therefore the engineering applications of monolithic polymers, requiring robust damage tolerance and high fracture toughness, are not ubiquitous. In addition, when “many-parts” cling together to form polymers, a labyrinth of molecules results, which does not offer to electrons and phonons a smooth and continuous passageway. Therefore, the monolithic polymers are bad conductors of heat and electricity. However, it is well established that when polymers are embedded with suitable entities especially nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials, their performance is propitiously improved. Among various additives, graphene has recently been employed as nano-filler to enhance mechanical, thermal, electrical, and functional properties of polymers. In this review, advances in the modeling and simulation of grapheme based polymer nanocomposites will be discussed in terms of graphene structure, topographical features, interfacial interactions, dispersion state, aspect ratio, weight fraction, and trade-off between variables and overall performance.展开更多
Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones suc...Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.展开更多
Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully...Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.展开更多
The environmental stress cracking resistance of halloysite nanoclay-polyester nanocomposites was investigated using fracture mechanics approach. The incorporation of halloysite nanoclay was found to improve the enviro...The environmental stress cracking resistance of halloysite nanoclay-polyester nanocomposites was investigated using fracture mechanics approach. The incorporation of halloysite nanoclay was found to improve the environmental stress cracking resistance of the nano-composites. The storage modulus of nano-composites measured by dynamic mechanical analysis increased remarkably as a function of halloysite nanoclay content. At 0.7 wt% nanoclay, the Tg improved from 72°C to 76°C. The fracture toughness increased up to 33% and time to failure improved 155% with the addition of 0.7 wt% of halloysite nanoclay. The maximum microhardness was found 119% higher for the same nano-filler concentration compared to monolithic polyester. The reinforcement with 1 wt% showed lower fracture toughness due to agglomerations of nanoclay which act as flaws. The presence of agglomerates weakened the bond between nano-particles and matrix hence reduces the environmental stress cracking resistance by halloysite nanoclay reinforcement.展开更多
Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub&g...Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub><sub>)</sub>, and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). The Rz of as-cast monolithic epoxy samples was 13.93 μm. By treating with velvet cloth, the R<sub>z</sub> value significantly decreased to 2.28 μm. The R<sub>z</sub> value of monolithic epoxy sample treated with abrasive paper 1200P was 4.85 μm which was also lower than that of as-cast monolithic epoxy samples. However, Rz values significantly increased by treating with abrasive papers 320P and 60P and became 20.32 μm and 39.32 μm, respectively. It was interesting to note that although R<sub>a</sub>, W<sub>a</sub>, and R<sub>q</sub>, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, R<sub>z</sub> decreased by abrasive paper 1200P. A weight loss of up to 17% was observed in monolithic epoxy samples after the treatment with the abrasive papers. Both V-shaped and U-shaped notches were produced on the surfaces of the samples. The mechanical properties were significantly degraded due to surface notches mainly because of the associated stress concentration effect. The topographical features also influenced the dynamic mechanical properties and fracture mode.展开更多
With the continuous development of electronic devices and the information industry towards miniaturization,integration,and high-power consumption,the using of electronic devices will inevitably generate and accumulate...With the continuous development of electronic devices and the information industry towards miniaturization,integration,and high-power consumption,the using of electronic devices will inevitably generate and accumulate heat,which will cause local high temperatures and will seriously reduce their performance,reliability,and lifetime.Therefore,having efficient heat-conducting functional materials is crucial to the normal and stable operation of electrical equipment and microelectronic products.In view of the excellent comprehensive performance of polymer-based thermally conductive materials(including intrinsic polymers and filler-filled polymer-based composites),it has shown great advantages in thermal management applications.In this review,the research status of preparing polymer-based thermally conductive composites and effective strategies to improve their thermal conductivity(TC)are reviewed.Compared with the higher cost and technical support with adjusting the molecular chain structure and cross-linking mode to improve the intrinsic TC of the polymer,introducing suitable fillers into the polymer to build a thermally conductive network or oriented structure can simply and efficiently improve the overall TC.Typical applications of polymer-based composites were discussed with detailed examples in the field of electronic packaging.Challenges and possible solutions to solve the issues are discussed together with the perspectives.This study provides guidance for the future development of polymer-based thermally conductive composites.展开更多
基金the China Scholarship Council(2021)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-249-03”.
文摘A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.
文摘The precipitation of secondary Laves phases and its effect on notch sensitivity are systematically studied in Thermo-Span alloy. The results show that the precipitation peak temperature of secondary Laves phases is 925 ℃. Below 925 ℃, the volume fraction of secondary Laves phases increases with the rise of the temperature, and its morphology changes from granular to thin-film;above 925 ℃, the volume fraction of secondary Laves phases shows an opposite trend to temperature, and its morphology changes from thin-film to granular. A detailed explanation through linear density (ρ) is provided that the influence of secondary Laves phases at the grain boundaries (GBs) on notch sensitivity depends on the coupling competition effect of their size, quantity, and morphology. Notably, the granular Laves phases are more beneficial to improving the notch sensitivity of the alloy compared with thin-film Laves phases. Granular secondary Laves phases can promote the formation of γ′ phases depletion zone to improve the ability of GBs to accommodate high strain localization, and effectively inhibit the crack initiation and propagation.
基金financially supported by the National Natural Science Foundation of China(Nos.52275567 and 52401242)Shanxi province key research and development program(No.202102050201006)+3 种基金the Funds for Local Scientific and Technological Development guided by the Central Government(No.YDZJSX2022A054)the Special Fund for Science and Technology Innovation Teams of Shanxi Province(No.202304051001036)Shanxi Province Basic Research Project(No.202403021221147)the Graduate Education Innovation Program Project of Taiyuan University of Science and Technology(No.BY2023001)
文摘Elemental modulation and heat treatment optimization have emerged as pivotal strategies for enhancing the soft magnetic properties of alloys.We thoroughly examine the impact of microalloyed Co on the amorphous formation ability,thermal stability,and soft magnetic properties of Fe_(80)Co_(x)Si_(7-x)B_(8)P_(4)Cu1(x=0,0.5,1,1.5,2)alloys.The influence of different annealing processes on these properties is analyzed through detailed insights into the evolution of nanocrystalline microstructure and magnetic domain behavior.Our findings indicate that Co addition facilitates the nucleation and growth of the a-Fe(Si,Co)phase while broadening the thermal processing window,thereby significantly improving the alloy’s soft magnetic properties.Notably,the alloy with x=1 undergoes a pre-annealing and reheating process to yield a finer,denser,and more uniform nanocrystalline structure(average grain size D=20.29 nm,grain density Nd=1.5×10^(23)m^(-3)).This refinement enables the formation of broad magnetic domains characterized by 180°domain walls,culminating in exceptional soft magnetic properties,including a high magnetic flux density(B_(s)=1.81 T),high effective permeability(μ_(e)=18,014),and low coercivity(H_(c)=5.57 A m^(-1)).Further,the pinning fields(Hp)for the x=1 alloy are notably low,ranging from15 to 20 A m^(-1),while the maximum effective permeability reaches 69,300.These exceptional properties are directly linked to the alloy’s minimized total free energy(E)and its highly homogeneous microstructure,which collectively suppress magnetic pinning effects.Such characteristics position the x=1 alloy as an exceptional candidate for high-sensitivity applications,particularly in sensor device systems functioning under mild magnetic fields and necessitating swift reaction.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB4003801)the National Natural Science Foundation of China(No.52076091)We appreciate the analysis and characterization assistance of FESEM,XRD,and Raman from the Analytical and Testing Center at Huazhong University of Science&Technology.The author acknowledges the tubular furnace from Anhui Chem-n Instrument Co.,Ltd.
文摘Vanadium nitride(VN),a promising cathode material for aqueous zinc ion batteries(AZIBs),undergoes irreversible phase transitions accompanied by structural variation and sustained vanadium dissolution,which impair cycling stability and reaction kinetics.To address these challenges,we designed a core–shell heterostructure(VONC-T,T represents temperature)composed of a VN core and a porous carbon shell.This structure was synthesized via in-situ construction,involving optimized ratio of coating a zinc-based zeolitic imidazolate framework(ZIF-8)onto a vanadium-based metal-organic framework(MIL-47(V)),followed by a thermal treatment.This process ensures a high degree of interfacial stability between the core and shell,effectively mitigating the structural variation of VN during irreversible phase transitions and enhancing the overall structural stability.During thermal driving,the volatilization of zinc within the shell layer created a porous channel effect,which facilitating Zn^(2+)diffusion.The enhancement of Zn²⁺diffusion strengthens the efficient conversion of VN to amorphous VOx,labeled as VONC-T-a,which provides more active sites and consequently results in a high specific capacity.The optimized heterostructure of VONC-900-a presented high reversible capacity of 387.2 mAh g^(−1)at 0.2 A g^(−1)and demonstrated excellent rate performance,achieving 274.5 mAh g^(−1)at 20 A g^(−1),while maintaining a capacity retention rate of 93.3%after 5000 cycles at 10 A g^(−1).Density functional theory calculations confirmed improved reaction kinetics in the core–shell structure.This study not only highlights the potential of amorphous vanadium oxide core–shell heterostructure for AZIBs but also provides new insights into the conversion mechanisms of VN.
基金supported by the China Postdoc-toral Science Foundation(No.2023M732495)the Shanxi Provincial Basic Research Program(Nos.202103021223180 and 202203021221120)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1261-02”.
文摘Low erosion high-energy propellant is one of the research directions to extend the weapon’s life and improve the weapon’s capability.In this study,energetic propellants containing different corrosion inhibitors were designed and prepared.Close bomb tests and semi-confined bomb experiments were used to investigate the burning and erosion properties of the propellants.The mechanism of erosion-reducing of titanium dioxide(titania,TiO_(2)),talc,and octaphenylsilsesquioxane(OPS)on the propellant was comparatively analyzed.The results show that OPS has the lowest burning rate and the longest burning time,and a minimized loss of fire force,with the best effect of explosion heat reduction.The erosion reduction efficiency of OPS is twice that of TiO_(2) and talc.The mechanism analysis shows that the decomposition and heat absorption of OPS can effectively reduce the thermal erosion effect and carbon erosion,and the gas produced can reduce the loss of chamber pressure and form a uniformly distributed nano-SiO_(2) protective layer.This solid-state high-efficiency organosilicon erosion inhibitor is an important guide for designing high-energy low-erosion gun propellants.
基金Projects(51775277,51775265)supported by the National Natural Science Foundation of ChinaProject(190624DF01)supported by Nanjing University of Aeronautics and Astronautics Short Visiting Program,China。
文摘A dynamic model of a flexible rotor supported by ball bearings with rubber damping rings was proposed by combining the finite element and the mass-centralized method.In the proposed model,the rotor was built with the Timoshenko beam element,while the supports and bearing outer rings were modelled by the mass-centralized method.Meanwhile,the influences of the rotor’s gravity,unbalanced force and nonlinear bearing force were considered.The governing equations were solved by precise integration and the Runge-Kutta hybrid numerical algorithm.To verify the correctness of the modelling method,theoretical and experimental analysis is carried out by a rotor-bearing test platform,where the error rate between the theoretical and experimental studies is less than 10%.Besides that,the influence of the rubber damping ring on the dynamic properties of the rotor-bearing coupling system is also analyzed.The conclusions obtained are in agreement with the real-world deployment.On this basis,the bifurcation and chaos behaviors of the coupling system were carried out with rotational speed and rubber damping ring’s stiffness.The results reveal that as rotational speed increases,the system enters into chaos by routes of crisis,quasi-periodic and intermittent bifurcation.However,the paths of crisis,quasi-periodic bifurcation,and Hopf bifurcation to chaos were detected under the parameter of rubber damping ring’s stiffness.Additionally,the bearing gap affects the rotor system’s dynamic characteristics.Moreover,the excessive bearing gap will make the system’s periodic motion change into chaos,and the rubber damping ring’s stiffness has a substantial impact on the system motion.
基金financial support from National Natural Science Foundation of China(21704096,51703217)the China Postdoctoral Science Foundation(Grant No.2019M662526)financial support from Taif University Researchers Supporting Project Number(TURSP-2020/135),Taif University,Taif,Saudi Arabia。
文摘With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.
基金financial support from Heriot-Watt University (Edinburgh)the Engineering and Physical Sciences Research Council (EP/K018345/1) for this study
文摘Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales. In this research, periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability. This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers, including polyvinyl chloride(PVC), polyethylene 1000(PE1000), polypropylene copolymer(PP) and polytetrafluoroethylene(PFTE), which cannot be processed by conventional semiconductor-based manufacturing processes. Materials exhibiting common wettability properties(θ≈ 90°) changed to exhibit "superhydrophobic" behavior(θ > 150°). Compared with the size of the structures, the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability.
基金Supported by the National Natural Science Foundation of China(No.21576112)Natural Science Foundation of Jilin Province(20150623024TC-19,20170520147JH)the Science and Technology Development Plan of Siping City(2015049)
文摘Six new transition metal complexes, [Zn（HBTC）（PYTPY）]n·n PYTPY（1）, [Cu（HBTC）（PYTPY）]n·n PYTPY（2）, [Co（HBTC）（PYTPY）]n·n DMF（3）, [Mn（HBTC）（PYTPY）]n·n DMF（4）, [Cd（HBTC）（PYTPY）（H2O）]n·2nH2O（5）, and [Co（HBTC）（PYTPY）（H2O）2]（6）,（H3BTC = 1,3,5-benzenetricarboxylic acid, PYTPY = 4＇-（4-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, DMF = N,N？-dimethylformamide）, have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complexes 1~5 all feature one-dimensional chain structures, and complex 6 exhibits a zero-dimensional structure. Complexes 1~5 present three-dimensional（3D） supramolecular frameworks via π-π stacking interactions, whenas 6 has also a 3D supramolecular structure assembled by hydrogen bonding. Meanwhile, complexes 1 ~ 6 exhibit the thermal stabilities and photoluminescent properties.
基金supported by National Key R&D Program(2022YFB2502000)Zhejiang Provincial Natural Science Foundation of China(LZ23B030003)+1 种基金the Fundamental Research Funds for the Central Universities(2021FZZX001-09)the National Natural Science Foundation of China(52175551).
文摘While the rechargeable aqueous zinc-ion batteries(AZIBs)have been recognized as one of the most viable batteries for scale-up application,the instability on Zn anode–electrolyte interface bottleneck the further development dramatically.Herein,we utilize the amino acid glycine(Gly)as an electrolyte additive to stabilize the Zn anode–electrolyte interface.The unique interfacial chemistry is facilitated by the synergistic“anchor-capture”effect of polar groups in Gly molecule,manifested by simultaneously coupling the amino to anchor on the surface of Zn anode and the carboxyl to capture Zn^(2+)in the local region.As such,this robust anode–electrolyte interface inhibits the disordered migration of Zn^(2+),and effectively suppresses both side reactions and dendrite growth.The reversibility of Zn anode achieves a significant improvement with an average Coulombic efficiency of 99.22%at 1 mA cm^(−2)and 0.5 mAh cm^(−2)over 500 cycles.Even at a high Zn utilization rate(depth of discharge,DODZn)of 68%,a steady cycle life up to 200 h is obtained for ultrathin Zn foils(20μm).The superior rate capability and long-term cycle stability of Zn–MnO_(2)full cells further prove the effectiveness of Gly in stabilizing Zn anode.This work sheds light on additive designing from the specific roles of polar groups for AZIBs.
文摘To control the power hierarchy design of lithium-ion battery(LIB)builtup sets for electric vehicles(EVs),we offer intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulated in full-scale LIB built-up models.As primary structural tectonics,heterogeneous composite superstructures of full-cell-LIB(anode//cathode)electrodes were designed in closely packed flower agave rosettes TiO2@C(FRTO@C anode)and vertical-star-tower LiFePO4@C(VST@C cathode)building blocks to regulate the electron/ion movement in the three-dimensional axes and orientation pathways.The superpower hierarchy surfaces and multi-directional orientation components may create isosurface potential electrodes with mobile electron movements,in-to-out interplay electron dominances,and electron/charge cloud distributions.This study is the first to evaluate the hotkeys of choice anode/cathode architectonics to assemble different LIB-electrode platforms with high-mobility electron/ion flows and high-performance capacity functionalities.Density functional theory calculation revealed that the FRTO@C anode and VST-(i)@C cathode architectonics are a superior choice for the configuration of full-scale LIB built-up models.The integrated FRTO@C//VST-(i)@C full-scale LIB retains a huge discharge capacity(~94.2%),an average Coulombic efficiency of 99.85%after 2000 cycles at 1 C,and a high energy density of 127 Wh kg?1,thereby satisfying scale-up commercial EV requirements.
基金Supported by the Military Medical Science and Technology Innovation Plan(No.SWH2016LHYS-07)Cultivation Plan of Military Medical Youth Sci-tech(No.18QNP001)。
文摘AIM:To assess the biosafety of a poly(acrylamide-cosodium acrylate)hydrogel(PAH)as a 3D-printed intraocular lens(IOL)material.METHODS:The biosafety of PAH was first evaluated in vitro using human lens epithelial cells(LECs)and the ARPE19 cell line,and a cell counting kit-8(CCK-8)assay was performed to investigate alterations in cell proliferation.A thin film of PAH and a conventional IOL were intraocularly implanted into the eyes of New Zealand white rabbits respectively,and a sham surgery served as control group.The anterior segment photographs,intraocular pressure(IOP),blood parameters and electroretinograms(ERG)were recorded.Inflammatory cytokines in the aqueous humor,such as TNFαand IL-8,were examined by ELISA.Cell apoptosis of the retina was investigated by TUNEL assay,and macro PAHge activation was detected by immunostaining.RESULTS:PAH did not slow cell proliferation when cocultured with human LECs or ARPE19 cells.The implantation of a thin film of a 3 D-printed IOL composed of PAH did not affect the IOP,blood parameters,ERG or optical structure in any of the three experimental groups(n=3 for each).Both TNFαand IL-8 in the aqueous humor of PAH group were transiently elevated 1 wk post-operation and recovered to normal levels at 1 and 3 mo post-operation.Iba1+macroPAHges in the anterior chamber angle in PAH group were increased markedly compared to those of the control group;however,there was no significant difference compared to those in the IOL group.CONCLUSION:PAH is a safe material for 3D printing of personal IOLs that hold great potential for future clinical applications.
基金supported by the National Natural Science Foundation of China(Nos.12202410 and 51906238)the China Postdoctoral Science Foundation(No.2023M733935)+4 种基金the Natural Science Foundation of Hunan Province(No.2023JJ40726)the Research Project Supported by the Shanxi Scholarship Council of China(No.2022-139)the Natural Science Foundation of Shanxi Province(Nos.20210302123017 and 2023recipient Changcheng Liu)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(No.20220012)the Changsha Municipal Natural Science Foundation(No.kq2208277).
文摘In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasing interest.In this work,a kind of core-shell structured microcapsule was synthesized by an in-situ polymerization,where paraffin was used as the core,while methanol was applied to mod-ify the melamine-formaldehyde shell to reduce toxicity and improve thermal stability.Moreover,three different types of heat conductive fillers with the same content of 10 wt.%,i.e.,nano-Al_(2)O_(3),nano-ZnO and carbon nanotubes were added,generating composites.The microcapsules were uniform,and were not affected by the thermal fillers,which were evenly dispersed around.The composite sample with carbon nanotubes(10 wt.%)showed the highest thermal conductivity of 0.50 W/(m K)and latent heat of 139.64 J/g.Furthermore,according to the leakage testing and battery charge/discharge experiments,compared with Al_(2)O_(3)and ZnO,the addition of carbon nanotubes remarkably enhances the heat storage ability as latent heat from 126.98 J/g for the prepared sample with Al_(2)O_(3)and 125.86 J/g for the one with ZnO,then to 139.64 J/g,as well as dissipation performance as a cooling effect by decreasing the sur-face temperature of battery from 2%to 12%of microcapsule,composite sample with carbon nanotubes presents a broad application prospect in battery thermal management system and energy storage field.
基金supported by the Key Scientific Re-search Project in Shanxi Province(Grant No.202102050201003)the Central Guiding Science and Technology Development of Local Fund(grant No.YDZJSK20231A046),+1 种基金the National Natural Sci-ence Foundation of China(Grant Nos.52071227,and 52275356)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research through project No.NBU-FPEJ-2024-249-01.
文摘Calcium(Ca)and neodymium(Nd)were introduced in the AZ61 alloy as alloying elements.The microstructure,corrosion behavior,and discharge properties of AZ61-1Nd-xCa(x=0,0.5 wt.%,1 wt.%,2 wt.%)alloys as anodes for Mg-air batteries were systematically investigated.The results indicated that the AZ61-1Nd-1Ca alloy exhibits the best corrosion resistance during electrochemical experiments and hydrogen evolution tests.Discharge performance tests showed that the AZ61-1Nd-1Ca alloy exhibits the best specific capacity(1193.6 mAh g^(-1)),energy density(1893.7 mWh g^(-1)),anode efficiency(60.3%),and cell voltage(1.246 V)at higher current densities.This is mainly attributed to the addition of Ca element,which refines the grain size of the alloy and increases the grain boundary area.In addition,Al_(2)Nd and Al_(2)Ca phases have similar corrosion mechanisms in the cross-section of the extruded alloy.The precipitated granular Al_(2)Ca phase is uniformly dispersed on the substrate and acts as a physical barrier.This not only enhances the corrosion resistance of the alloy but also improves the anode efficiency of the alloy during discharge.
文摘Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found applications in numerous fields. The stiff and fragile structure of monolithic polymers leads to the innate cracks to cause fracture and therefore the engineering applications of monolithic polymers, requiring robust damage tolerance and high fracture toughness, are not ubiquitous. In addition, when “many-parts” cling together to form polymers, a labyrinth of molecules results, which does not offer to electrons and phonons a smooth and continuous passageway. Therefore, the monolithic polymers are bad conductors of heat and electricity. However, it is well established that when polymers are embedded with suitable entities especially nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials, their performance is propitiously improved. Among various additives, graphene has recently been employed as nano-filler to enhance mechanical, thermal, electrical, and functional properties of polymers. In this review, advances in the modeling and simulation of grapheme based polymer nanocomposites will be discussed in terms of graphene structure, topographical features, interfacial interactions, dispersion state, aspect ratio, weight fraction, and trade-off between variables and overall performance.
基金supported by the Engineering and Physical Sciences Research Council(EPSRC)of the U.K.(Grant No.EP/P018998/1)the Acoustofluidics Special Interest Group of the UK Fluids Network(Grant No.EP/N032861/1)the EPSRC Centre for Doctoral Training in Renewable Energy Northeast Universities(ReNU)(Grant No.EP/S023836/1).
文摘Ice nucleation and accretion on structural surfaces are sources of major safety and operational concerns in many industries including aviation and renewable energy.Common methods for tackling these are active ones such as heating,ultrasound,and chemicals or passive ones such as surface coatings.In this study,we explored the ice adhesion properties of slippery coated substrates by measuring the shear forces required to remove a glaze ice block on the coated substrates.Among the studied nanostructured and nanoscale surfaces[i.e.,a superhydrophobic coating,a fluoropolymer coating,and a polydimethylsiloxane(PDMS)chain coating],the slippery omniphobic covalently attached liquid(SOCAL)surface with its flexible polymer brushes and liquid-like structure significantly reduced the ice adhesion on both glass and silicon surfaces.Further studies of the SOCAL coating on roughened substrates also demonstrated its low ice adhesion.The reduction in ice adhesion is attributed to the flexible nature of the brush-like structures of PDMS chains,allowing ice to detach easily.
基金This work was financially sup-ported by the National Natural Science Foundation of China(NSFC Nos:22171212,21771140,51771138,51979194)International Corporation Project of Shanghai Committee of Science and Technology by China(No.21160710300)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.
文摘The environmental stress cracking resistance of halloysite nanoclay-polyester nanocomposites was investigated using fracture mechanics approach. The incorporation of halloysite nanoclay was found to improve the environmental stress cracking resistance of the nano-composites. The storage modulus of nano-composites measured by dynamic mechanical analysis increased remarkably as a function of halloysite nanoclay content. At 0.7 wt% nanoclay, the Tg improved from 72°C to 76°C. The fracture toughness increased up to 33% and time to failure improved 155% with the addition of 0.7 wt% of halloysite nanoclay. The maximum microhardness was found 119% higher for the same nano-filler concentration compared to monolithic polyester. The reinforcement with 1 wt% showed lower fracture toughness due to agglomerations of nanoclay which act as flaws. The presence of agglomerates weakened the bond between nano-particles and matrix hence reduces the environmental stress cracking resistance by halloysite nanoclay reinforcement.
文摘Influence of topographical features on mechanical properties of monolithic epoxy samples has been studied. The topographical features studied include waviness (W<sub>a</sub>), roughness average (R<sub>a</sub>), root mean square value (R<sub>q</sub><sub>)</sub>, and maximum roughness height (R<sub>max</sub> or R<sub>z</sub>). The Rz of as-cast monolithic epoxy samples was 13.93 μm. By treating with velvet cloth, the R<sub>z</sub> value significantly decreased to 2.28 μm. The R<sub>z</sub> value of monolithic epoxy sample treated with abrasive paper 1200P was 4.85 μm which was also lower than that of as-cast monolithic epoxy samples. However, Rz values significantly increased by treating with abrasive papers 320P and 60P and became 20.32 μm and 39.32 μm, respectively. It was interesting to note that although R<sub>a</sub>, W<sub>a</sub>, and R<sub>q</sub>, all increased by treating the monolithic epoxy samples with abrasive paper 1200P, however, R<sub>z</sub> decreased by abrasive paper 1200P. A weight loss of up to 17% was observed in monolithic epoxy samples after the treatment with the abrasive papers. Both V-shaped and U-shaped notches were produced on the surfaces of the samples. The mechanical properties were significantly degraded due to surface notches mainly because of the associated stress concentration effect. The topographical features also influenced the dynamic mechanical properties and fracture mode.
基金We acknowledge the Henan Young Backbone Teachers Foundation(No.2021GGJS135)。
文摘With the continuous development of electronic devices and the information industry towards miniaturization,integration,and high-power consumption,the using of electronic devices will inevitably generate and accumulate heat,which will cause local high temperatures and will seriously reduce their performance,reliability,and lifetime.Therefore,having efficient heat-conducting functional materials is crucial to the normal and stable operation of electrical equipment and microelectronic products.In view of the excellent comprehensive performance of polymer-based thermally conductive materials(including intrinsic polymers and filler-filled polymer-based composites),it has shown great advantages in thermal management applications.In this review,the research status of preparing polymer-based thermally conductive composites and effective strategies to improve their thermal conductivity(TC)are reviewed.Compared with the higher cost and technical support with adjusting the molecular chain structure and cross-linking mode to improve the intrinsic TC of the polymer,introducing suitable fillers into the polymer to build a thermally conductive network or oriented structure can simply and efficiently improve the overall TC.Typical applications of polymer-based composites were discussed with detailed examples in the field of electronic packaging.Challenges and possible solutions to solve the issues are discussed together with the perspectives.This study provides guidance for the future development of polymer-based thermally conductive composites.
