The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical *** studies have demonst...
详细信息
The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical *** studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the *** this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%*** results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc *** ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.
The performances of magnesium alloys remain insufficient to further enhance the application potential of ultralight magnesium *** this work,a Mg-8Li-3Y-2Zn alloy was prepared through vacuum melting and subsequent heat ...
详细信息
The performances of magnesium alloys remain insufficient to further enhance the application potential of ultralight magnesium *** this work,a Mg-8Li-3Y-2Zn alloy was prepared through vacuum melting and subsequent heat treatment at 300,450,and 500°*** material properties of the resulting samples were assessed through microstructural observation,tensile testing,electrical conductivity measurements,and electromagnetic shielding effectiveness(EMI-SE)*** influence of the Mg-8Li-3Y-2Zn alloy microstructure on its mechanical and electromagnetic shielding properties in different states was *** was found that the as-cast alloy containsα-Mg,β-Li,Mg_(3)Zn_(3)Y_(2),and Mg_(12)ZnY *** heat treatment at 500℃(HT500),the blockα-Mg phase transformedfine needle-shapes,its tensile strength increased to 263.7 MPa,and its elongation reached 45.3%.The mechanical properties of the alloy were significantly improved by the synergistic effects imparted by the needle-shapedα-Mg phase,solid solution strengthening,and precipitation *** addition of Y and Zn improved the EMI-SE of Mg-8Li-1Zn alloy,wherein the HT500 sample exhibits the highest SE,maintaining a value of 106.7–76.9 dB in the frequency range of 30–4500 MHz;this performance has rarely been reported for electromagnetically shielded *** effect was mainly attributed to the multiple reflections of electromagnetic waves caused by the severe impedance mismatch of the abundant phase boundaries,which were in turn provided by the dual-phase(α/β)and secondary ***,the presence of nano-precipitation was also believed to enhance the absorption of electromagnetic waves.
The Internet of Vehicles(IoVs)has seen rapid development due to advances in advanced communication *** 5-th Generation(5G)systems will be integrated into next-generation vehicles,enabling them to operate more efficien...
详细信息
The Internet of Vehicles(IoVs)has seen rapid development due to advances in advanced communication *** 5-th Generation(5G)systems will be integrated into next-generation vehicles,enabling them to operate more efficiently by cooperating with the *** millimeter Wave(mmWave)technology is projected to provide a large bandwidth to meet future needs for more effective data rate communications.A viable approach for transferring raw sensor data among autonomous vehicles would be to use mmWave *** paper attracts various research interests in academic,indoor,and outdoor mmWave *** paper presents mmWave propagation measurements for indoor and outdoor at 66 GHz frequency for IoVs *** proposed model examines the equivalent path loss using Free-Space Path Loss(FSPL)based on the transmitter and receiver distances for indoor and outdoor communications of the *** the indoor scenario,path loss propagation has the lowest penetration loss,but it is ineffective in the outdoor scenario because distance increases as free space path loss *** probability of error is increased,concerning the transmitter and receiver distances due to propagation effect,packet collisions,busy receiver,and sensing *** proposed methodology shows a higher packet delivery ratio and average throughput with less delay in the connection during transmission.
In order to comprehend the applicability of microwave irradiation for recovering coalbed methane,it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of *** this work,...
详细信息
In order to comprehend the applicability of microwave irradiation for recovering coalbed methane,it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of *** this work,the carbon molecular sieve combined with KMnO_(4)oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees,which can serve as model substances toward ***,the microwave irradiation dependences of pores,functional groups,and highpressure methane adsorption characteristics of model substances were *** results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups,which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve;meanwhile,naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 *** alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%,suggesting that microwave irradiation could promote methane ***,the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH4 *** summary,the oxidized carbon molecular sieve can act as model substances toward coals with different ***,microwave irradiation is a promising technology to enhance coalbed methane recovery.
In this work,a novel microwave absorbing material(MAM)made of a pseudo-binary of Sr_(2)TiMoO_(6)-Al_(2)O_(3)(STM)is proposed *** MAMs labeled as STM X(X=60,70,80 and 100,respectively),in which X is the initial weight ...
详细信息
In this work,a novel microwave absorbing material(MAM)made of a pseudo-binary of Sr_(2)TiMoO_(6)-Al_(2)O_(3)(STM)is proposed *** MAMs labeled as STM X(X=60,70,80 and 100,respectively),in which X is the initial weight percent of Sr_(2)TiMoO_(6),were synthesized using the solid-state reaction *** with STM100,some equilibrium phases,including SrTiO_(3),Mo,Sr_(8)(Al1_(2)O_(24))(MoO_(4))_(2)and a few undefined ones,are presented in the composites as evidenced by X-ray diffraction results and scanning electron microscopy due to the chemical reaction between Sr_(2)TiMoO_(6)and Al_(2)O_(3)*** conductance loss,heterogeneous interfaces between various equilibrium phases introduce interfacial polarization,which causes an enhancement of dissipation for the incident electromagnetic *** the synthesized samples,STM80 presents the best microwave absorbing *** has a minimum reflection loss(RLmin)of-26 dB and an effective absorbing bandwidth up to 2.7 GHz when the thickness is only 1 *** indicates that STM80 is a new type of microwave absorbing material with strong absorption and ultrathin thickness.
A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction(SSI)on high-rise *** addition,the difference between the seismic performance of ...
详细信息
A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction(SSI)on high-rise *** addition,the difference between the seismic performance of using twisting towers over regular ones is *** twisting tower is a simulation of the Evolution Tower(Moscow).The towers’skeletons consist of RC elements and rest on a reinforced concrete piled-raft *** soil model is considered as multi-layered with the same soil properties as the zone chosen for the analysis(New Mansoura City,Egypt).The only difference between both towers is their shape in *** whole system is modelled and analyzed in a single step as one full 3D model,which is known as the direct approach in *** analyses are carried out using finite-element software(Midas GTS NX).Dynamic output responses due to three records of seismic loads are proposed and presented in some *** on the results,it is concluded that SSI has a considerable effect on the dynamic response of tall buildings mainly because of the foundation flexibility,as it leads to lengthening the vibration period,increasing the story drift and the base shear for both cases.
In this study,non-thermal plasma(NTP)was employed to modify the Cu/TiO_(2)adsorbent to efficiently purify H_(2)S in low-temperature and micro-oxygen *** effects of Cu loading amounts and atmospheres of NTP treatment o...
详细信息
In this study,non-thermal plasma(NTP)was employed to modify the Cu/TiO_(2)adsorbent to efficiently purify H_(2)S in low-temperature and micro-oxygen *** effects of Cu loading amounts and atmospheres of NTP treatment on the adsorption-oxidation performance of the adsorbents were *** NTP modification successfully boosted the H_(2)S removal capacity to varying degrees,and the optimized adsorbent treated by air plasma(Cu/TiO_(2)-Air)attained the best H_(2)S breakthrough capacity of 113.29 mg H_(2)S/gadsorbent,which was almost 5 times higher than that of the adsorbent without NTP *** studies demonstrated that the superior performance of Cu/TiO_(2)-Air was attributed to increased mesoporous volume,more exposure of active sites(CuO)and functional groups(amino groups and hydroxyl groups),enhanced Ti-O-Cu interaction,and the favorable ratio of active oxygen ***,the X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)results indicated the main reason for the deactivationwas the consumption of the active components(CuO)and the agglomeration of reaction products(CuS and SO_(4)^(2−))occupying the active sites on the surface and the inner pores of the adsorbents.
We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide *** the real-space Hamiltonian,analytical expressions are ...
详细信息
We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide *** the real-space Hamiltonian,analytical expressions are derived for the transport spectra scattered by these two giant atoms with four azimuthal ***-like resonance can be exhibited in the scattering spectra by adjusting the azimuthal angle *** concurrence of the entangled state for two atoms can be implemented in a wide angle-difference range,and the entanglement of the atomic states can be switched on/off by modulating the additional azimuthal angle differences from the giant *** suggests a novel handle to effectively control the single-photon scattering and quantum entanglement.
Organocatalysis has shown special potency for simplifying the construction of complex polymer *** are reporting here a one-pot synthetic pathway using amine as a selectivity-switching agent in the two-component cataly...
详细信息
Organocatalysis has shown special potency for simplifying the construction of complex polymer *** are reporting here a one-pot synthetic pathway using amine as a selectivity-switching agent in the two-component catalytic system consisting of triethylborane(Et_(3)B)and a phosphazene *** first modelled the interactions of a variety of amines with Et_(3)B by density functional theory *** results indicate that the aliphatic diamines comprising both primary and tertiary amino groups,capable of forming stable intramolecular hydrogen bonds,undergo the strongest complexation with Et_(3)***,experimental results demonstrate that the addition of such amines promptly actuates the in situ selectivity switch from Lewis pair-catalyzed ring-opening polymerization(ROP)of epoxide(propylene oxide,n-butylglycidyl ether,or glycidyl phenyl ether)to organobase-catalyzed ROP ofδ-valerolactone,allowing one-pot continuous synthesis of ether-ester type block *** thus exploited the noncovalent interaction between amine and Et_(3)B to refine the catalyst switch strategy by exempting it from loading of extra catalyst.
Surface wave inversion is a key step in the application of surface waves to soil velocity ***,a common practice for the process of inversion is that the number of soil layers is assumed to be known before using heuris...
详细信息
Surface wave inversion is a key step in the application of surface waves to soil velocity ***,a common practice for the process of inversion is that the number of soil layers is assumed to be known before using heuristic search algorithms to compute the shear wave velocity profile or the number of soil layers is considered as an optimization ***,an improper selection of the number of layers may lead to an incorrect shear wave velocity *** this study,a deep learning and genetic algorithm hybrid learning procedure is proposed to perform the surface wave inversion without the need to assume the number of soil ***,a deep neural network is adapted to learn from a large number of synthetic dispersion curves for inferring the layer ***,the shear-wave velocity profile is determined by a genetic algorithm with the known layer *** applying this procedure to both simulated and real-world cases,the results indicate that the proposed method is reliable and efficient for surface wave inversion.
暂无评论