In the present work,seven Mg-Zn-Ag alloys with the nominal composition of Mg_(96-x)Zn_(x)Ag_(4)(x=17,20,23,26,29,32,35 in at.%)were prepared by induction melting and single-roller melt-spinning.The X-ray diffraction(X...In the present work,seven Mg-Zn-Ag alloys with the nominal composition of Mg_(96-x)Zn_(x)Ag_(4)(x=17,20,23,26,29,32,35 in at.%)were prepared by induction melting and single-roller melt-spinning.The X-ray diffraction(XRD)analyses indicate the metallic glasses with three composition of Mg_(73)Zn_(23)Ag_(4),Mg_(70)Zn_(26)Ag_(4),and Mg_(67)Zn_(29)Ag_(4)were obtained successfully.The differential scanning calorimetry(DSC)measurement was used to obtain the characteristic temperature of Mg-Zn-Ag metallic glasses for the glass-forming ability analysis.The maximum glass transition temperature(Trg)was found to be 0.525 with a composition close to Mg_(67)Zn_(29)Ag_(4),which results in the best glass-forming ability.Moreover,the immersion test in simulated body fluid(SBF)demonstrate the relative homogeneous corrosion behavior of the Mg-Zn-Ag metallic glasses.The corrosion rate of Mg-Zn-Ag metallic glasses in SBF solution decreases with the increase of Zn content.The sample Mg_(67)Zn_(29)Ag_(4)has the lowest corrosion rate of 0.19mm/yr,which could meet the clinical application requirement well.The in vitro cell experiments show that the Madin-Darby canine kidney(MDCK)cells cultured in sample Mg_(67)Zn_(29)Ag_(4)and its extraction medium have higher activity.However,the Mg-Zn-Ag metallic glasses exhibit obvious inhibitory effect on human rhabdomyosarcoma(RD)tumor cells.The present investigations on the glass-forming ability,corrosion behavior,cytocompatibility and tumor inhibition function of the Mg-Zn-Ag based metallic glass could reveal their biomedical application possibility.展开更多
The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progres...The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conic-approximation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.展开更多
Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability...Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.展开更多
The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were...The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were studied for size distribution, texture, and elemental geochemistry to establish chronostratigraphic markers for regional and global Quaternary correlation. The textural features of fine-grained(silty) volcanic glasses suggest the distal source of these tephra deposits. Major element composition with elevated SiO_(2) contents ranging between75%–76% and dominance of K_(2)O(> 4.5%) over CaO(< 0.9%) suggest ashes have originated from siliceous rhyolitic melts, similar to the petrographic composition of tephra from the Toba volcano. The bulk trace element compositions of the same glass shards were comparable with those reported in the youngest Toba tephra reported elsewhere. Likewise, the LREE-dominated chondrite normalized REE profiles of tephra from the Mahanadi basin closely resemble the characteristic REE patterns in Toba ash from other parts of the Indian Ocean and thus confirmed the contribution of the youngest Toba super-eruption for this ash layers.展开更多
A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical properties....A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical properties.The nonlinear evolution of glass transition temperature(T_(g))with the addition of ZnO is ascribed to the competition of two converse factors,i e,the T_(g)depression as one of the colligative properties for a solution,on the one hand,and the enhancement of T_(g)due to the higher field strength of zinc cations compared to that of alkali ions.However,the nonlinear evolution of elastic moduli and coefficients of thermal expansion with r is attributed to the variance of intermediate-range clusters,which is confirmed by infrared and Raman scattering spectra.These findings are very helpful in tailoring the performance of borosilicate glasses.展开更多
Elastoplastic constitutive equation of glass is proposed in this article,which is formulated based on the subloading surface model which possesses the various distinguished advantages for the description of the plasti...Elastoplastic constitutive equation of glass is proposed in this article,which is formulated based on the subloading surface model which possesses the various distinguished advantages for the description of the plastic deformation,i.e.,the smooth elastic-plastic transition,the continuous variation of the tangent stiff-ness modulus tensor,the automatic controlling function to attract the stress to the yield surface during the plastic deformation process,etc.It would be the firstly proposed three-dimensional elastoplastic con-stitutive equation of glass,which is furnished with the basic properties,e.g.the ellipsoidal yield surface with the dependence of the third deviatoric stress invariant,undergoing the flattering to the deviatoric direction with the plastic compression and the plastic volumetric hardening with the associated flow rule.The validity of the description of the deformation behavior of glass will be verified by comparisons with some test data for silica glass specimens.展开更多
Amorphous solids exhibit scale-free avalanches,even under small external loading,and thus can work as suitable systems to study critical behavior and universality classes.The abundance of scale-free avalanches in the ...Amorphous solids exhibit scale-free avalanches,even under small external loading,and thus can work as suitable systems to study critical behavior and universality classes.The abundance of scale-free avalanches in the entire elastic tension regime of bulk metallic glass(BMG)samples has been experimentally observed using acoustic emission(AE)measurements.In this work,we compare the statistics of avalanches with those of earthquakes,and find that they both follow the Gutenberg–Richter law in the statistics of energies and Omori’s law of aftershock rates,and share the same characteristics in the distribution of recurrence times.These resemblances encourage us to propose the term“glass-quake”to describe avalanches in elastically loaded BMGs.Furthermore,our work echoes the potential universality of critical behavior in disordered physical systems from atomic to planetary scales,and motivates the use of elastic loaded BMGs as valuable laboratory simulators of seismic dynamics.展开更多
Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sedi...Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass shards.Relative to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related origin.The colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(<1%),low Sr/Y(<15)and high Ba/Th ratios(>100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial affinity.In contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite magma.Brown glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol Arc.Establishing the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.展开更多
In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calcula...In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants.展开更多
Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin re...Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin responsible for the variation of properties remains poorly understood.In the present work,we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins.Specifically,we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl(Tl is the liquidus temperature)to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating.We found that glass transition temperature,Tg,increases by as much as 36 K,and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl.The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys.The incorporated oxygen and silicon can both enhance the interactions between atoms,which renders the cooperative rearrangements of atoms difficult,and thus enhances the kinetic stability of the MGs.展开更多
The alteration in surface color of metallic glasses(MGs)holds great significance in the context of microstructuredesign and commercial utility.It is essential to accurately describe the structures that are formed duri...The alteration in surface color of metallic glasses(MGs)holds great significance in the context of microstructuredesign and commercial utility.It is essential to accurately describe the structures that are formed during the laser and colorseparation processes in order to develop practical laser coloring applications.Due to the high oxidation sensitivity of Labasedmetallic glass,it can broaden the color range but make it more complex.Structure coloring by laser processing on thesurface of La-based metallic glass can be conducted after thermoplastic forming.It is particularly important to clarify therole of structure and composition in the surface coloring process.The aim is to study the relationship between amorphoussurface structural color,surface geometry,and oxide formation by laser processing in metallic glasses.The findings revealedthat the periodic structure primarily determines the surface color at laser energy densities below 1.0 J/mm^(2).In contrast,thesurface color predominantly depends on the proportion of oxides that are formed when energy densities exceed 1.0 J/mm^(2).Consequently,this study provides a novel concept for the fundamental investigation of laser coloring and establishes a newavenue for practical application.展开更多
In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)...In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)O_(3)/SiO_(2) ratio,the simple structural units Q_(1) and Q_(2) transformed into highly aggregated structural units Q_(3) and Q_(4),indicating the increase of polymerization degree of glass network.Meanwhile,the coefficient of thermal expansion decreased from 9.23×10^(-6)℃^(-1) to 8.88×10^(-6)℃^(-1).The characteristic temperatures such as melting,forming,softening and glass transition temperatures increased with the increase of Al_(2)O_(3)/SiO_(2) ratio,while the glasses working temperature range became narrow.The increasing Al_(2)O_(3)/SiO_(2) ratio and prolonging ion-exchange time enhanced the surface compressive stress(CS)and depth of stress layer(DOL).However,the increase of ion exchange temperature increased the DOL and decreased the CS affected by stress relaxation.There was a good linear relationship between stress relaxation and surface compressive stress.Chemical strengthening significantly improved the hardness of glasses,which reached the maximum value of(622.1±10)MPa for sample with Al_(2)O_(3)/SiO_(2) ratio of 0.27 after heat treated at 410℃for 2 h.展开更多
The reconstruction of paleo-elevation serves a dual purpose to enhance our comprehension of geodynamic processes affecting terrestrial landforms and to contribute significantly to the interpretation of atmospheric cir...The reconstruction of paleo-elevation serves a dual purpose to enhance our comprehension of geodynamic processes affecting terrestrial landforms and to contribute significantly to the interpretation of atmospheric circulation and biodiversity.The oxygen(δ~(18)O_w)and deuterium(δD_w)isotopes in atmospheric precipitation are systematically depleted with the increase of altitude,which are typical and widely applicated paleo-altimeters.The utilization of hydrogen isotope of hydrous silicate minerals within the shear zone system,volcanic glass,and plant leaf wax alkanes offers valuable insights for addressing evaporation and diagenesis.In this paper,we review the principle,application conditions,and influencing factors of the hydrogen isotope paleo-altimeter.In addition,we discuss the feasibility of utilizing this technique for quantitatively estimating the paleo-elevation of the southeastern Tibetan Plateau,where multiple shear zones extend over hundred kilometers parallel to the topographic gradient.展开更多
Solid waste recycling is an economically sound strategy for preserving the environment,safeguarding natural resources,and diminishing the reliance on raw material consumption.Geopolymer technology offers a significant...Solid waste recycling is an economically sound strategy for preserving the environment,safeguarding natural resources,and diminishing the reliance on raw material consumption.Geopolymer technology offers a significant advantage by enabling the reuse and recycling of diverse materials.This research assesses how including silica fume and glass powder enhances the impact resistance of ultra-high-performance geopolymer concrete(UHPGC).In total,18 distinct mixtures were formulated by substituting ground granulated blast furnace slag with varying proportions of silica fume and glass powder,ranging from 10%to 40%.Similarly,for each of the mixtures above,steel fibre was added at a dosage of 1.5%to address the inherent brittleness of UHPGC.The mixtures were activated by combining sodium hydroxide and sodium silicate solution to generate geopolymer binders.The specimens were subjected to drop-weight impact testing,wherein an examination was carried out to evaluate various parameters,including flowability,density at fresh and hardened state,compressive strength,impact numbers indicative of cracking and failure occurrences,ductility index,and analysis of failure modes.Additionally,the variations in the impact test outcomes were analyzed using the Weibull distribution,and the findings corresponding to survival probability were offered.Furthermore,the microstructure of UHPGC was scrutinized through scanning electron microscopy.Findings reveal that the specimens incorporating glass powder exhibited lower cracking impact number values than those utilizing silica fume,with reductions ranging from 18.63%to 34.31%.Similarly,failure impact number values decreased from 8.26%to 28.46%across glass powder contents.The maximum compressive and impact strength was recorded in UHPGC,comprising 10%silica fume with fibres.展开更多
The calcium aluminosilicate-based glasses(CaO-Al_(2)O_(3)-SiO_(2),CAS)with different Fe_(2)O_(3)content(0.10wt%,0.50wt%,0.90wt%,and 1.30wt%)were prepared by traditional melt-quenching method.The glass network structur...The calcium aluminosilicate-based glasses(CaO-Al_(2)O_(3)-SiO_(2),CAS)with different Fe_(2)O_(3)content(0.10wt%,0.50wt%,0.90wt%,and 1.30wt%)were prepared by traditional melt-quenching method.The glass network structure,thermal and mechanical properties,and crystallization behavior changes were investigated by nuclear magnetic resonance spectrometer,Fourier-transform infrared spectro-photometer,X-ray diffractometer,differential scanning calorimetry and field emission scanning electron microscope measurements.The change of Q^(n)in glass structures reveals the glass network connectivity decreases due to the increasing content of Fe_(2)O_(3)addition,resulting in the increasing of non-bridging number in glass structure.The glass densities slightly rise from 2.644 to 2.681 g/cm^(3),while Vickers’s hardness increases at first,from 6.469 to 6.901 GPa,then slightly drops to 6.745 GPa,with Fe_(2)O_(3)content increase.There is almost no thermal expansion coefficient change from different Fe_(2)O_(3)content.The glass transmittance in visible range gradually decreases with higher Fe_(2)O_(3)content,resulting from the strong absorption of Fe^(2+)and Fe^(3+)ions.The calculated activation energy from thermal analysis results first decreases from 282.70 to 231.18 kJ/mol,and then increases to 244.02 kJ/mol,with the Fe_(2)O_(3)content increasing from 0.10wt%to 1.30wt%.Meanwhile,the maximum Avrami constant of 2.33 means the CAS glasses exhibit two-dimensional crystallization.All of the CAS glass-ceramics samples contain main crystal phase of anorthite,the microstructure appears lamellar and columnar crystals.展开更多
Kinetically constrained spin systems are toy models of supercooled liquids and amorphous solids. In this perspective,we revisit the prototypical Fredrickson–Andersen(FA) kinetically constrained model from the viewpoi...Kinetically constrained spin systems are toy models of supercooled liquids and amorphous solids. In this perspective,we revisit the prototypical Fredrickson–Andersen(FA) kinetically constrained model from the viewpoint of K-core combinatorial optimization. Each kinetic cluster of the FA system, containing all the mutually visitable microscopic occupation configurations, is exactly the solution space of a specific instance of the K-core attack problem. The whole set of different jammed occupation patterns of the FA system is the configuration space of an equilibrium K-core problem. Based on recent theoretical results achieved on the K-core attack and equilibrium K-core problems, we discuss the thermodynamic spin glass phase transitions and the maximum occupation density of the fully unfrozen FA kinetic cluster, and the minimum occupation density and extreme vulnerability of the partially frozen(jammed) kinetic clusters. The equivalence between K-core attack and the fully unfrozen FA kinetic cluster also implies a new way of sampling K-core attack solutions.展开更多
Lead-free low melting glasses,ZnO-CuO-Bi_(2)O_(3)-B_(2)O_(3)-SiO_(2)system,with fixed contents of 15 mol%CuO and 20 mol%Bi_(2)O_(3),were prepared by using melt cooling method.Structure and thermal properties of the gl...Lead-free low melting glasses,ZnO-CuO-Bi_(2)O_(3)-B_(2)O_(3)-SiO_(2)system,with fixed contents of 15 mol%CuO and 20 mol%Bi_(2)O_(3),were prepared by using melt cooling method.Structure and thermal properties of the glasses were studied by using X-ray diffractometer(XRD),infrared spectrometer(FIT-IR),thermal dilatometer and differential thermal analyzer(DTA).Chemical durability of the glasses was studied by using dissolution rate method.Wettability of glasses on substrate was tested by using button sintering experiment.It is found that alkaline resistance of the glass solders is lower than that of plate glass and the water resistance is comparable with that of plate glass.The sealing temperatures are Ts=445-490℃,while the average thermal expansion coefficient from room temperature to 300℃is in the range of(65-82)×10^(−7)℃^(−1).At sealing temperature,the glass solders have good wettability on plate glass or alumina substrate.They are not crystallized even sintered at the sealing temperature for 30 min.The solder glasses are suitable for sealing plate glass,alumina and other inorganic non-metallic materials.展开更多
Cu^(+)-doped alkali borosilicate glasses with different Na_(2)O contents were prepared by the melting method,and the effects of different R values(R=Na_(2)O/B_(2)O_(3))on the structure,ion presence state and luminesce...Cu^(+)-doped alkali borosilicate glasses with different Na_(2)O contents were prepared by the melting method,and the effects of different R values(R=Na_(2)O/B_(2)O_(3))on the structure,ion presence state and luminescence properties of Cu^(+)-doped alkali borosilicate glasses were investigated.The analysis by FT-IR and Raman spectroscopy shows that,with the increase of R value of the glass,the[BO_(3)]in the structure of Cu^(+)-doped alkali borosilicate glass transforms into[BO_(4)]and the number of non-bridging oxygen in the glass network appears to be slightly increased.The absorption spectra and EPR analysis reveal that the Cu^(+)content in the glass gradually decreases and the Cu^(2+)content gradually increases as the R value of the glass increases.XPS and PL tests further indicate that the transformation of the octahedral coordination structure of Cu^(+)to the octahedral coordination structure of Cu^(2+)and the cubic coordination structure of Cu^(+)occurs in the glass as the R value of the glass increases.This transformation can effectively reduce the concentration quenching phenomenon of Cu^(+)and improve the fluorescence luminescence intensity of the glass samples.Meanwhile,the samples were found to have luminescence tunability as well as good thermal stability.展开更多
One hallmark of glasses is the existence of excess vibrational modes at low frequenciesωbeyond Debye’s prediction.Numerous studies suggest that understanding low-frequency excess vibrations could help gain insight i...One hallmark of glasses is the existence of excess vibrational modes at low frequenciesωbeyond Debye’s prediction.Numerous studies suggest that understanding low-frequency excess vibrations could help gain insight into the anomalous mechanical and thermodynamic properties of glasses.However,there is still intensive debate as to the frequency dependence of the population of low-frequency excess vibrations.In particular,excess modes could hybridize with phonon-like modes and the density of hybridized excess modes has been reported to follow D_(exc)(ω)~ω^(2)in 2D glasses with an inverse power law potential.Yet,the universality of the quadratic scaling remains unknown,since recent work suggested that interaction potentials could influence the scaling of the vibrational spectrum.Here,we extend the universality of the quadratic scaling for hybridized excess modes in 2D to glasses with potentials ranging from the purely repulsive soft-core interaction to the hard-core one with both repulsion and attraction as well as to glasses with significant differences in density or interparticle repulsion.Moreover,we observe that the number of hybridized excess modes exhibits a decrease in glasses with higher density or steeper interparticle repulsion,which is accompanied by a suppression of the strength of the sound attenuation.Our results indicate that the density bears some resemblance to the repulsive steepness of the interaction in influencing low-frequency properties.展开更多
Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law s...Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies.展开更多
基金National Key Research and Development Program of China(2018YFC1106702)Guangdong Basic and Applied Basic Research Foundation(2020A1515011301,2019A1515110067 and 2020A1515110055)+1 种基金Shenzhen Basic Research Project(JCYJ20210324120001003,JCYJ20200109144608205 and JCYJ20200109144604020)IER Foundation(HT-JDCXY-201902 and HT-JD-CXY-201907)for financial support.
文摘In the present work,seven Mg-Zn-Ag alloys with the nominal composition of Mg_(96-x)Zn_(x)Ag_(4)(x=17,20,23,26,29,32,35 in at.%)were prepared by induction melting and single-roller melt-spinning.The X-ray diffraction(XRD)analyses indicate the metallic glasses with three composition of Mg_(73)Zn_(23)Ag_(4),Mg_(70)Zn_(26)Ag_(4),and Mg_(67)Zn_(29)Ag_(4)were obtained successfully.The differential scanning calorimetry(DSC)measurement was used to obtain the characteristic temperature of Mg-Zn-Ag metallic glasses for the glass-forming ability analysis.The maximum glass transition temperature(Trg)was found to be 0.525 with a composition close to Mg_(67)Zn_(29)Ag_(4),which results in the best glass-forming ability.Moreover,the immersion test in simulated body fluid(SBF)demonstrate the relative homogeneous corrosion behavior of the Mg-Zn-Ag metallic glasses.The corrosion rate of Mg-Zn-Ag metallic glasses in SBF solution decreases with the increase of Zn content.The sample Mg_(67)Zn_(29)Ag_(4)has the lowest corrosion rate of 0.19mm/yr,which could meet the clinical application requirement well.The in vitro cell experiments show that the Madin-Darby canine kidney(MDCK)cells cultured in sample Mg_(67)Zn_(29)Ag_(4)and its extraction medium have higher activity.However,the Mg-Zn-Ag metallic glasses exhibit obvious inhibitory effect on human rhabdomyosarcoma(RD)tumor cells.The present investigations on the glass-forming ability,corrosion behavior,cytocompatibility and tumor inhibition function of the Mg-Zn-Ag based metallic glass could reveal their biomedical application possibility.
基金supported by National Key R&D Program of China (2022YFF0709101)China National Space Administration (D050104)National Natural Science Foundation of China (62105244 and U2030111)。
文摘The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conic-approximation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.
基金supported by the Sichuan Science and Technology Program (Grant Nos.2023NSFSC0004,2023NSFSC0790)the National Natural Science Foundation of China (Grant Nos.51827901,52304033)the Sichuan University Postdoctoral Fund (Grant No.2024SCU12093)。
文摘Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.
基金We thank the Directors of CSIR-NIO and CSIR-NGRI,for supporting this studyThis work is a part of a multidisciplinary program under the aegis of the National Gas Hydrate Program(NGHP),India,on gas hydrate exploration in the Eastern continental margin of India.The incharge of IPEV operations is thanked for providing onboard technical support and facilities.This research was funded by MoES,Govt.of India.Mr.Girish Prabhu and Mr.Vijay Khedekar are thanked for XRD and SEM analyses,respectively.This is NIO contribution no.7047.
文摘The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were studied for size distribution, texture, and elemental geochemistry to establish chronostratigraphic markers for regional and global Quaternary correlation. The textural features of fine-grained(silty) volcanic glasses suggest the distal source of these tephra deposits. Major element composition with elevated SiO_(2) contents ranging between75%–76% and dominance of K_(2)O(> 4.5%) over CaO(< 0.9%) suggest ashes have originated from siliceous rhyolitic melts, similar to the petrographic composition of tephra from the Toba volcano. The bulk trace element compositions of the same glass shards were comparable with those reported in the youngest Toba tephra reported elsewhere. Likewise, the LREE-dominated chondrite normalized REE profiles of tephra from the Mahanadi basin closely resemble the characteristic REE patterns in Toba ash from other parts of the Indian Ocean and thus confirmed the contribution of the youngest Toba super-eruption for this ash layers.
基金Funded by National Natural Science Foundation of China(No.52172007)the Ph D Program Fund of Non-Metallic Excellence and Innovation Center for Building Materials(No.2022SFP6-2)+1 种基金the Key Technology Innovation Project of Hubei Province(No.2022BAA025)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010312)。
文摘A series of mixed alkali-zinc borosilicate glasses with various r values(r=molar ratio of[ZnO]/([R^(2)O]+[ZnO]))from 0.00 to 1.00 were fabricated to probe the mixed alkali-zinc effects on thermo-mechanical properties.The nonlinear evolution of glass transition temperature(T_(g))with the addition of ZnO is ascribed to the competition of two converse factors,i e,the T_(g)depression as one of the colligative properties for a solution,on the one hand,and the enhancement of T_(g)due to the higher field strength of zinc cations compared to that of alkali ions.However,the nonlinear evolution of elastic moduli and coefficients of thermal expansion with r is attributed to the variance of intermediate-range clusters,which is confirmed by infrared and Raman scattering spectra.These findings are very helpful in tailoring the performance of borosilicate glasses.
文摘Elastoplastic constitutive equation of glass is proposed in this article,which is formulated based on the subloading surface model which possesses the various distinguished advantages for the description of the plastic deformation,i.e.,the smooth elastic-plastic transition,the continuous variation of the tangent stiff-ness modulus tensor,the automatic controlling function to attract the stress to the yield surface during the plastic deformation process,etc.It would be the firstly proposed three-dimensional elastoplastic con-stitutive equation of glass,which is furnished with the basic properties,e.g.the ellipsoidal yield surface with the dependence of the third deviatoric stress invariant,undergoing the flattering to the deviatoric direction with the plastic compression and the plastic volumetric hardening with the associated flow rule.The validity of the description of the deformation behavior of glass will be verified by comparisons with some test data for silica glass specimens.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51801122 and 52071210)the Science Challenge Project(Grant No.TZ2018001)the Science and Technology Commission of Shanghai(Grant No.21ZR1430800).
文摘Amorphous solids exhibit scale-free avalanches,even under small external loading,and thus can work as suitable systems to study critical behavior and universality classes.The abundance of scale-free avalanches in the entire elastic tension regime of bulk metallic glass(BMG)samples has been experimentally observed using acoustic emission(AE)measurements.In this work,we compare the statistics of avalanches with those of earthquakes,and find that they both follow the Gutenberg–Richter law in the statistics of energies and Omori’s law of aftershock rates,and share the same characteristics in the distribution of recurrence times.These resemblances encourage us to propose the term“glass-quake”to describe avalanches in elastically loaded BMGs.Furthermore,our work echoes the potential universality of critical behavior in disordered physical systems from atomic to planetary scales,and motivates the use of elastic loaded BMGs as valuable laboratory simulators of seismic dynamics.
基金Supported by the National Natural Science Foundation of China(Nos.42076049,42376050)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)the Laoshan Laboratory(No.LSKJ202204201)。
文摘Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass shards.Relative to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related origin.The colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(<1%),low Sr/Y(<15)and high Ba/Th ratios(>100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial affinity.In contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite magma.Brown glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol Arc.Establishing the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.
基金the financial supports from the Shenzhen Basic Research Project,China(No.JCYJ20170815153210359)the National Natural Science Foundation of China(No.12174210)。
文摘In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants.
基金The work was financially supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0703600,2021YFA0716302,and 2021YFA0718703)the National Natural Science Foundation of China(Grant Nos.51825104 and 52192602)China Postdoctoral Science Foundation(Grant No.2022T150691).
文摘Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin responsible for the variation of properties remains poorly understood.In the present work,we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins.Specifically,we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl(Tl is the liquidus temperature)to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating.We found that glass transition temperature,Tg,increases by as much as 36 K,and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl.The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys.The incorporated oxygen and silicon can both enhance the interactions between atoms,which renders the cooperative rearrangements of atoms difficult,and thus enhances the kinetic stability of the MGs.
基金supported by the National Natural Science Foundation of China(Grant Nos.52071222 and 52471180)Guangdong Major Project of Basic and Applied Basic Research,China(Grant No.2019B030302010)+2 种基金Guangdong Basic and Applied Basic Research,China(Grant No.2020B1515130007)the National Key Research and Development Program of China(Grant No.2021YFA0716302)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000).
文摘The alteration in surface color of metallic glasses(MGs)holds great significance in the context of microstructuredesign and commercial utility.It is essential to accurately describe the structures that are formed during the laser and colorseparation processes in order to develop practical laser coloring applications.Due to the high oxidation sensitivity of Labasedmetallic glass,it can broaden the color range but make it more complex.Structure coloring by laser processing on thesurface of La-based metallic glass can be conducted after thermoplastic forming.It is particularly important to clarify therole of structure and composition in the surface coloring process.The aim is to study the relationship between amorphoussurface structural color,surface geometry,and oxide formation by laser processing in metallic glasses.The findings revealedthat the periodic structure primarily determines the surface color at laser energy densities below 1.0 J/mm^(2).In contrast,thesurface color predominantly depends on the proportion of oxides that are formed when energy densities exceed 1.0 J/mm^(2).Consequently,this study provides a novel concept for the fundamental investigation of laser coloring and establishes a newavenue for practical application.
基金Funded by National Natural Science Foundation of China(Nos.52172019 and 52072148)Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022K1100)。
文摘In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)O_(3)/SiO_(2) ratio,the simple structural units Q_(1) and Q_(2) transformed into highly aggregated structural units Q_(3) and Q_(4),indicating the increase of polymerization degree of glass network.Meanwhile,the coefficient of thermal expansion decreased from 9.23×10^(-6)℃^(-1) to 8.88×10^(-6)℃^(-1).The characteristic temperatures such as melting,forming,softening and glass transition temperatures increased with the increase of Al_(2)O_(3)/SiO_(2) ratio,while the glasses working temperature range became narrow.The increasing Al_(2)O_(3)/SiO_(2) ratio and prolonging ion-exchange time enhanced the surface compressive stress(CS)and depth of stress layer(DOL).However,the increase of ion exchange temperature increased the DOL and decreased the CS affected by stress relaxation.There was a good linear relationship between stress relaxation and surface compressive stress.Chemical strengthening significantly improved the hardness of glasses,which reached the maximum value of(622.1±10)MPa for sample with Al_(2)O_(3)/SiO_(2) ratio of 0.27 after heat treated at 410℃for 2 h.
基金supported by the National Key Research and Development program of China(Grant No.2021YFC3000604)National Natural Science Foundation of China(Grant Nos.42030305,42272257)sponsored by State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration(Grant No.LED2022B04)。
文摘The reconstruction of paleo-elevation serves a dual purpose to enhance our comprehension of geodynamic processes affecting terrestrial landforms and to contribute significantly to the interpretation of atmospheric circulation and biodiversity.The oxygen(δ~(18)O_w)and deuterium(δD_w)isotopes in atmospheric precipitation are systematically depleted with the increase of altitude,which are typical and widely applicated paleo-altimeters.The utilization of hydrogen isotope of hydrous silicate minerals within the shear zone system,volcanic glass,and plant leaf wax alkanes offers valuable insights for addressing evaporation and diagenesis.In this paper,we review the principle,application conditions,and influencing factors of the hydrogen isotope paleo-altimeter.In addition,we discuss the feasibility of utilizing this technique for quantitatively estimating the paleo-elevation of the southeastern Tibetan Plateau,where multiple shear zones extend over hundred kilometers parallel to the topographic gradient.
基金SASTRA Deemed University,India for its generous research support。
文摘Solid waste recycling is an economically sound strategy for preserving the environment,safeguarding natural resources,and diminishing the reliance on raw material consumption.Geopolymer technology offers a significant advantage by enabling the reuse and recycling of diverse materials.This research assesses how including silica fume and glass powder enhances the impact resistance of ultra-high-performance geopolymer concrete(UHPGC).In total,18 distinct mixtures were formulated by substituting ground granulated blast furnace slag with varying proportions of silica fume and glass powder,ranging from 10%to 40%.Similarly,for each of the mixtures above,steel fibre was added at a dosage of 1.5%to address the inherent brittleness of UHPGC.The mixtures were activated by combining sodium hydroxide and sodium silicate solution to generate geopolymer binders.The specimens were subjected to drop-weight impact testing,wherein an examination was carried out to evaluate various parameters,including flowability,density at fresh and hardened state,compressive strength,impact numbers indicative of cracking and failure occurrences,ductility index,and analysis of failure modes.Additionally,the variations in the impact test outcomes were analyzed using the Weibull distribution,and the findings corresponding to survival probability were offered.Furthermore,the microstructure of UHPGC was scrutinized through scanning electron microscopy.Findings reveal that the specimens incorporating glass powder exhibited lower cracking impact number values than those utilizing silica fume,with reductions ranging from 18.63%to 34.31%.Similarly,failure impact number values decreased from 8.26%to 28.46%across glass powder contents.The maximum compressive and impact strength was recorded in UHPGC,comprising 10%silica fume with fibres.
基金Funded by the Key Research and Development Program of Han Nan province(No.ZDYF2021GXJS027)the Project of Sanya Yazhou Bay Science and Technology City(No.SCKJJYRC-2022-44)the Shenzhen Virtual University Park(SZVUP)Free Exploration Basic Research Project(No.2021Szvup107)。
文摘The calcium aluminosilicate-based glasses(CaO-Al_(2)O_(3)-SiO_(2),CAS)with different Fe_(2)O_(3)content(0.10wt%,0.50wt%,0.90wt%,and 1.30wt%)were prepared by traditional melt-quenching method.The glass network structure,thermal and mechanical properties,and crystallization behavior changes were investigated by nuclear magnetic resonance spectrometer,Fourier-transform infrared spectro-photometer,X-ray diffractometer,differential scanning calorimetry and field emission scanning electron microscope measurements.The change of Q^(n)in glass structures reveals the glass network connectivity decreases due to the increasing content of Fe_(2)O_(3)addition,resulting in the increasing of non-bridging number in glass structure.The glass densities slightly rise from 2.644 to 2.681 g/cm^(3),while Vickers’s hardness increases at first,from 6.469 to 6.901 GPa,then slightly drops to 6.745 GPa,with Fe_(2)O_(3)content increase.There is almost no thermal expansion coefficient change from different Fe_(2)O_(3)content.The glass transmittance in visible range gradually decreases with higher Fe_(2)O_(3)content,resulting from the strong absorption of Fe^(2+)and Fe^(3+)ions.The calculated activation energy from thermal analysis results first decreases from 282.70 to 231.18 kJ/mol,and then increases to 244.02 kJ/mol,with the Fe_(2)O_(3)content increasing from 0.10wt%to 1.30wt%.Meanwhile,the maximum Avrami constant of 2.33 means the CAS glasses exhibit two-dimensional crystallization.All of the CAS glass-ceramics samples contain main crystal phase of anorthite,the microstructure appears lamellar and columnar crystals.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12247104 and 12047503)。
文摘Kinetically constrained spin systems are toy models of supercooled liquids and amorphous solids. In this perspective,we revisit the prototypical Fredrickson–Andersen(FA) kinetically constrained model from the viewpoint of K-core combinatorial optimization. Each kinetic cluster of the FA system, containing all the mutually visitable microscopic occupation configurations, is exactly the solution space of a specific instance of the K-core attack problem. The whole set of different jammed occupation patterns of the FA system is the configuration space of an equilibrium K-core problem. Based on recent theoretical results achieved on the K-core attack and equilibrium K-core problems, we discuss the thermodynamic spin glass phase transitions and the maximum occupation density of the fully unfrozen FA kinetic cluster, and the minimum occupation density and extreme vulnerability of the partially frozen(jammed) kinetic clusters. The equivalence between K-core attack and the fully unfrozen FA kinetic cluster also implies a new way of sampling K-core attack solutions.
基金National Natural Science Foundation of China(52172070)Jiangxi Provincial Natural Science Foundation(20242BAB25222)Jiangxi Provincial Graduate Innovation Special Fund Project(YC2022-S882 and YC2023-S808).
文摘Lead-free low melting glasses,ZnO-CuO-Bi_(2)O_(3)-B_(2)O_(3)-SiO_(2)system,with fixed contents of 15 mol%CuO and 20 mol%Bi_(2)O_(3),were prepared by using melt cooling method.Structure and thermal properties of the glasses were studied by using X-ray diffractometer(XRD),infrared spectrometer(FIT-IR),thermal dilatometer and differential thermal analyzer(DTA).Chemical durability of the glasses was studied by using dissolution rate method.Wettability of glasses on substrate was tested by using button sintering experiment.It is found that alkaline resistance of the glass solders is lower than that of plate glass and the water resistance is comparable with that of plate glass.The sealing temperatures are Ts=445-490℃,while the average thermal expansion coefficient from room temperature to 300℃is in the range of(65-82)×10^(−7)℃^(−1).At sealing temperature,the glass solders have good wettability on plate glass or alumina substrate.They are not crystallized even sintered at the sealing temperature for 30 min.The solder glasses are suitable for sealing plate glass,alumina and other inorganic non-metallic materials.
基金Funded by the Key R&D Projects in Hubei Province of China(No:2020BAB061)。
文摘Cu^(+)-doped alkali borosilicate glasses with different Na_(2)O contents were prepared by the melting method,and the effects of different R values(R=Na_(2)O/B_(2)O_(3))on the structure,ion presence state and luminescence properties of Cu^(+)-doped alkali borosilicate glasses were investigated.The analysis by FT-IR and Raman spectroscopy shows that,with the increase of R value of the glass,the[BO_(3)]in the structure of Cu^(+)-doped alkali borosilicate glass transforms into[BO_(4)]and the number of non-bridging oxygen in the glass network appears to be slightly increased.The absorption spectra and EPR analysis reveal that the Cu^(+)content in the glass gradually decreases and the Cu^(2+)content gradually increases as the R value of the glass increases.XPS and PL tests further indicate that the transformation of the octahedral coordination structure of Cu^(+)to the octahedral coordination structure of Cu^(2+)and the cubic coordination structure of Cu^(+)occurs in the glass as the R value of the glass increases.This transformation can effectively reduce the concentration quenching phenomenon of Cu^(+)and improve the fluorescence luminescence intensity of the glass samples.Meanwhile,the samples were found to have luminescence tunability as well as good thermal stability.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12374202 and 12004001)Anhui Projects(Grant Nos.2022AH020009,S020218016,and Z010118169)+1 种基金Hefei City(Grant No.Z020132009)Anhui University(start-up fund)。
文摘One hallmark of glasses is the existence of excess vibrational modes at low frequenciesωbeyond Debye’s prediction.Numerous studies suggest that understanding low-frequency excess vibrations could help gain insight into the anomalous mechanical and thermodynamic properties of glasses.However,there is still intensive debate as to the frequency dependence of the population of low-frequency excess vibrations.In particular,excess modes could hybridize with phonon-like modes and the density of hybridized excess modes has been reported to follow D_(exc)(ω)~ω^(2)in 2D glasses with an inverse power law potential.Yet,the universality of the quadratic scaling remains unknown,since recent work suggested that interaction potentials could influence the scaling of the vibrational spectrum.Here,we extend the universality of the quadratic scaling for hybridized excess modes in 2D to glasses with potentials ranging from the purely repulsive soft-core interaction to the hard-core one with both repulsion and attraction as well as to glasses with significant differences in density or interparticle repulsion.Moreover,we observe that the number of hybridized excess modes exhibits a decrease in glasses with higher density or steeper interparticle repulsion,which is accompanied by a suppression of the strength of the sound attenuation.Our results indicate that the density bears some resemblance to the repulsive steepness of the interaction in influencing low-frequency properties.
基金the support from the National Natural Science Foundation of China(Grant Nos.12374202 and 12004001)Anhui Projects(Grant Nos.2022AH020009,S020218016,and Z010118169)Hefei City(Grant No.Z020132009)。
文摘Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies.