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1.
Magnetic and magnetocaloric properties of the amorphous Fe92−xZr8Bx ribbons were studied in this work. Fully amorphous Fe89Zr8B3, Fe88Zr8B4, and Fe87Zr8B5 ribbons were fabricated. The Curie temperature (Tc), saturation magnetization (Ms), and the maximum entropy change with the variation of a magnetic field (−ΔSmpeak) of the glassy ribbons were significantly improved by the boron addition. The mechanism for the enhanced Tc and −ΔSmpeak by boron addition was studied. 相似文献
2.
Yixuan He Yuhao Wu Fan Bu Yiyuan Zhang Yifan Zhang Bo Hei Jianbao Zhang Haifeng Wang 《Materials》2022,15(4)
The undercooling (∆T) dependencies of the solidification pathways, microstructural evolution, and recalescence behaviors of undercooled Co-18.5at.%B eutectic alloys were systematically explored. Up to four possible solidification pathways were identified: (1) A lamellar eutectic structure consisting of the FCC–Co and Co3B phase forms, with extremely low ΔT; (2) The FCC–Co phase primarily forms, followed by the eutectic growth of the FCC–Co and Co2B phases when ΔT < 100 K; (3) As the ΔT increases further, the FCC–Co phase primarily forms, followed by the metastable Co23B6 phase with the trace of an FCC–Co and Co23B6 eutectic; (4) When the ΔT increases to 277 K, the FCC–Co phase primarily forms, followed by an FCC–Co and Co3B eutectic, which is similar in composition to the microstructure formed with low ΔT. The mechanisms of the microstructural evolution and the phase selection are interpreted on the basis of the composition segregation, the skewed coupled zone, the strain-induced transformation, and the solute trapping. Moreover, the prenucleation of the primary FCC–Co phase was also detected from an analysis of the different recalescence behaviors. The present work not only enriches our knowledge about the phase selection behavior in the undercooled Co–B system, but also provides us with guidance for controlling the microstructures and properties practically. 相似文献
3.
Anatoliy Popovich Pavel Novikov Qingsheng Wang Konstantin Pushnitsa Daniil Aleksandrov 《Materials》2021,14(24)
Li3FeN2 material was synthesized by the two-step solid-state method from Li3N (adiabatic camera) and FeN2 (tube furnace) powders. Phase investigation of Li3N, FeN2, and Li3FeN2 was carried out. The discharge capacity of Li3FeN2 is 343 mAh g−1, which is about 44.7% of the theoretic capacity. The ternary nitride Li3FeN2 molar heat capacity is calculated using the formula Cp,m = 77.831 + 0.130 × T − 6289 × T−2, (T is absolute temperature, temperature range is 298–900 K, pressure is constant). The thermodynamic characteristics of Li3FeN2 have the following values: entropy S0298 = 116.2 J mol−1 K−1, molar enthalpy of dissolution ΔdHLFN = −206.537 ± 2.8 kJ mol−1, the standard enthalpy of formation ΔfH0 = −291.331 ± 5.7 kJ mol−1, entropy S0298 = 113.2 J mol−1 K−1 (Neumann–Kopp rule) and 116.2 J mol−1 K−1 (W. Herz rule), the standard Gibbs free energy of formation ΔfG0298 = −276.7 kJ mol−1. 相似文献
4.
Solid-state reaction was used for Li7La3Zr2O12 material synthesis from Li2CO3, La2O3 and ZrO2 powders. Phase investigation of Li7La3Zr2O12 was carried out by x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) methods. The thermodynamic characteristics were investigated by calorimetry measurements. The molar heat capacity (Cp,m), the standard enthalpy of formation from binary compounds (ΔoxHLLZO) and from elements (ΔfHLLZO), entropy (S0298), the Gibbs free energy of the Li7La3Zr2O12 formation (∆f G0298) and the Gibbs free energy of the LLZO reaction with metallic Li (∆rGLLZO/Li) were determined. The corresponding values are Cp,m = 518.135 + 0.599 × T − 8.339 × T−2, (temperature range is 298–800 K), ΔoxHLLZO = −186.4 kJ·mol−1, ΔfHLLZO = −9327.65 ± 7.9 kJ·mol−1, S0298 = 362.3 J·mol−1·K−1, ∆f G0298 = −9435.6 kJ·mol−1, and ∆rGLLZO/Li = 8.2 kJ·mol−1, respectively. Thermodynamic performance shows the possibility of Li7La3Zr2O12 usage in lithium-ion batteries. 相似文献
5.
This study focuses on the phenol biodegradation kinetics by Stenotrophomonas maltophilia KB2 in a nickel-contaminated medium. Initial tests proved that a nickel concentration of 33.3 mg·L−1 caused a cessation of bacterial growth. The experiments were conducted in a batch bioreactor in several series: without nickel, at constant nickel concentration and at varying metal concentrations (1.67–13.33 g·m−3). For a constant Ni2+ concentration (1.67 or 3.33 g·m−3), a comparable bacterial growth rate was obtained regardless of the initial phenol concentration (50–300 g·m−3). The dependence µ = f (S0) at constant Ni2+ concentration was very well described by the Monod equations. The created varying nickel concentrations experimental database was used to estimate the parameters of selected mathematical models, and the analysis included different methods of determining metal inhibition constant KIM. Each model showed a very good fit with the experimental data (R2 values were higher than 0.9). The best agreement (R2 = 0.995) was achieved using a modified Andrews equation, which considers the metal influence and substrate inhibition. Therefore, kinetic equation parameters were estimated: µmax = 1.584 h−1, KS = 185.367 g·m−3, KIS = 106.137 g·m−3, KIM = 1.249 g·m−3 and n = 1.0706. 相似文献
6.
Kenya Nakajima Marc Leparoux Hiroki Kurita Briac Lanfant Di Cui Masahito Watanabe Takenobu Sato Fumio Narita 《Materials》2022,15(3)
Fe–Co alloys are attracting attention as magnetostrictive materials for energy harvesting and sensor applications. This work investigated the magnetostriction characteristics and crystal structure of additive-manufactured Fe–Co alloys using directed energy deposition. The additive-manufactured Fe–Co parts tended to exhibit better magnetostrictive performance than the hot-rolled Fe–Co alloy. The anisotropy energy ΔK1 for the Fe–Co bulk, prepared under a power of 300 W (referred to as bulk−300 W), was larger than for the rolled sample. For the bulk−300 W sample in a particular plane, the piezomagnetic constant d was large, irrespective of the direction of the magnetic field. Elongated voids that formed during additive manufacturing changed the magnetostrictive behavior in a direction perpendicular to these voids. Magnetic property measurements showed that the coercivity decreased. Since sensors should be highly responsive, Fe–Co three-dimensional parts produced via additive manufacturing can be applied as force sensors. 相似文献
7.
Incorporating with inhomogeneous phases with high electroluminescence (EL) intensity to prepare smart meta-superconductors (SMSCs) is an effective method for increasing the superconducting transition temperature (Tc) and has been confirmed in both MgB2 and Bi(Pb)SrCaCuO systems. However, the increase of ΔTc (ΔTc = Tc ‒ Tcpure) has been quite small because of the low optimal concentrations of inhomogeneous phases. In this work, three kinds of MgB2 raw materials, namely, aMgB2, bMgB2, and cMgB2, were prepared with particle sizes decreasing in order. Inhomogeneous phases, Y2O3:Eu3+ and Y2O3:Eu3+/Ag, were also prepared and doped into MgB2 to study the influence of doping concentration on the ΔTc of MgB2 with different particle sizes. Results show that reducing the MgB2 particle size increases the optimal doping concentration of inhomogeneous phases, thereby increasing ΔTc. The optimal doping concentrations for aMgB2, bMgB2, and cMgB2 are 0.5%, 0.8%, and 1.2%, respectively. The corresponding ΔTc values are 0.4, 0.9, and 1.2 K, respectively. This work open a new approach to reinforcing increase of ΔTc in MgB2 SMSCs. 相似文献
8.
The thermal history of melts leads to three liquid states above the melting temperatures Tm containing clusters—bound colloids with two opposite values of enthalpy +Δεlg × ΔHm and −Δεlg × ΔHm and zero. All colloid bonds disconnect at Tn+ > Tm and give rise in congruent materials, through a first-order transition at TLL = Tn+, forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (Tn+) and (TLL) are separated, Tn+ being the temperature of a second order and TLL the temperature of a first-order phase transition. (Tn+) and (TLL) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at TLL gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at Tn+ or from Tn+ to Tg. These liquid enthalpies reveal the natural presence of colloid–colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states. 相似文献
9.
Sanbo Qin Huan-Xiang Zhou 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(17):6974-6979
Restrictocin belongs to a family of site-specific ribonucleases that kill cells by inactivating the ribosome. The restrictocin–ribosome binding rate constant was observed to exceed 1010 M−1 s−1. We have developed a transient-complex theory to model the binding rates of protein–protein and protein–RNA complexes. The theory predicts the rate constant as ka = ka0 exp(−ΔGel*/kBT), where ka0 is the basal rate constant for reaching the transient complex, located at the outer boundary of the bound state, by random diffusion, and ΔGel* is the average electrostatic interaction free energy of the transient complex. Here, we applied the transient-complex theory to dissect the high restrictocin–ribosome binding rate constant. We found that the binding rate of restrictocin to the isolated sarcin/ricin loop is electrostatically enhanced by ≈300-fold, similar to results found in other protein–protein and protein–RNA complexes. The ribosome provides an additional 10,000-fold rate enhancement because of two synergistic mechanisms afforded by the distal regions of the ribosome. First, they provide additional electrostatic attraction with restrictocin. Second, they reposition the transient complex into a region where local electrostatic interactions of restrictocin with the sarcin/ricin loop are particularly favorable. Our calculations rationalize a host of experimental observations and identify a strategy for designing proteins that bind their targets with high speed. 相似文献
10.
Processing of Waste from Enrichment with the Production of Cement Clinker and the Extraction of Zinc
Alexandr Kolesnikov Roman Fediuk Olga Kolesnikova Nurgali Zhanikulov Bibol Zhakipbayev Rasim Kuraev Elmira Akhmetova Aizhan Shal 《Materials》2022,15(1)
This paper presents studies on the processing of enrichment tailings as a component of a raw mixture in order to obtain cement clinker, with simultaneous distillation of zinc. Thermodynamic studies were carried out in the temperature range of 600–1600 °C using the software application “HSC Chemistry 6” developed by the metallurgical company Outokumpu (Finland). As a result of the conducted studies, we found that zinc contributes to the intensification of mineral formation of cement clinker. In particular, it was found that the formation of belite is possible in the temperature range from 990.7 to 1500 °C with Gibbs energy values of −0.01 and −323.8 kJ (which is better than the standard process by −11.4 kJ), respectively; the formation of alite is possible in the temperature range from 982.9 to 1500 °C with Gibbs energy values of −0.05 and −402.1 kJ (better than the standard process by −11.4 kJ), respectively; the formation of tricalcium aluminate is thermodynamically possible in the temperature range from 600 °C at ΔGTo = −893.8 kJ to 1500 °C at ΔGTo = −1899.3 kJ (better than the standard process by −1570.1 kJ), respectively; and the formation of four calcium aluminoferrite is possible in the temperature range from 600 °C at ΔGTo = −898.9 kJ to 1500 °C at ΔGTo = −1959.3 kJ (better than the standard process by −1570.2 kJ), respectively, with simultaneous distillation of zinc into a gaseous state for its further capture. 相似文献
11.
Petr Tome? Matthias Trottmann Clemens Suter Myriam Heidi Aguirre Aldo Steinfeld Philipp Haueter Anke Weidenkaff 《Materials》2010,3(4):2801-2814
The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM). These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La1.98Sr0.02CuO4) and two n-type (CaMn0.98Nb0.02O3) thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS) which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al2O3 substrate compared to the uncoated surface on ΔT, Pmax and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm-2 and the dependence of η on the leg length was investigated. 相似文献
12.
Kingshuk Ghosh Ken A. Dill 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(26):10649-10654
New amino acid sequences of proteins are being learned at a rapid rate, thanks to modern genomics. The native structures and functions of those proteins can often be inferred using bioinformatics methods. We show here that it is also possible to infer the stabilities and thermal folding properties of proteins, given only simple genomics information: the chain length and the numbers of charged side chains. In particular, our model predicts ΔH(T), ΔS(T), ΔCp, and ΔF(T) —the folding enthalpy, entropy, heat capacity, and free energy—as functions of temperature T; the denaturant m values in guanidine and urea; the pH-temperature-salt phase diagrams, and the energy of confinement F(s) of the protein inside a cavity of radius s. All combinations of these phase equilibria can also then be computed from that information. As one illustration, we compute the pH and salt conditions that would denature a protein inside a small confined cavity. Because the model is analytical, it is computationally efficient enough that it could be used to automatically annotate whole proteomes with protein stability information. 相似文献
13.
Ern Kuzmann Israel Felner Laura Szirki Sndor Stichleutner Zoltn Homonnay Mahmoud R. El-Sharif Colin U. Chisholm 《Materials》2022,15(9)
Sn-Fe-Ni-Co quaternary alloys, in the composition range of 37–44 at% Sn, 35–39 at% Fe, 6–8 at% Ni and 13–17 at% Co, were prepared by direct current (DC) and pulse plating (PP) electrodeposition. The alloy deposits were characterized by XRD, 57Fe and 119Sn conversion electron Mössbauer spectroscopy, SEM-EDX and magnetization measurements. XRD revealed the amorphous character of the quaternary alloy deposits. The dominant ferromagnetic character of the deposits was shown by magnetization and Mössbauer spectroscopy measurements. Room temperature Mössbauer spectra showed minor paramagnetic phases, where their occurrences (~3–20%) are correlated to the electrodeposition parameters (Jdep from −16 to −23 mA/cm2 for DC, Jpulse from −40 to −75 mA/cm2 for PP), the composition and the saturation magnetization (~52–73 emu/g). A considerable difference was found in the magnetization curves applying parallel or perpendicular orientation of the applied fields, indicating magnetic anisotropy both in DC and pulse plated alloy coatings. 相似文献
14.
The arc-melting method was adopted to prepare the compound La0.5Pr0.5(Fe1−xCox)11.4Si1.6 (x = 0, 0.02, 0.04, 0.06, 0.08), and the magnetocaloric effect of the compound was investigated. As indicated by the powder X-ray diffraction (XRD) results, after receiving 7-day high temperature annealing at 1373 K, all the compounds formed a single-phase cubic NaZn13 crystal structure. As indicated by the magnetic measurement, the most significant magnetic entropy change |∆SM(T)| of the sample decreased from 28.92 J/kg·K to 4.22 J/kg·K with the increase of the Co content under the 0–1.5 T magnetic field, while the Curie temperature TC increased from 185 K to the room temperature 296 K, which indicated that this series of alloys are the room temperature magnetic refrigerant material with practical value. By using the ferromagnetic Curie temperature theory and analyzing the effect of Co doping on the exchange integral of these alloys, the mechanism that the Curie temperature of La0.5Pr0.5(Fe1−xCox)11.4Si1.6 and La0.8Ce0.2(Fe1−xCox)11.4Si1.6 increased with the increase in the Co content was reasonably explained. Accordingly, this paper can provide a theoretical reference for subsequent studies. 相似文献
15.
xPb(In1/2Nb1/2)O3-(1−x−y)Pb(Mg1/3Nb2/3)O3−yPbTiO3 (PIN–PMN–PT) bulks possess excellent electromechanical coupling and dielectric properties, but the corresponding epitaxial PIN–PMN–PT thin films have not yet been explored. This paper adopts a nonlinear thermodynamics analysis to investigate the influences of misfit strains on the phase structures, electromechanical properties, and electrocaloric responses in epitaxial PIN–PMN–PT thin films. The misfit strain–temperature phase diagram was constructed. The results reveal that the PIN–PMN–PT thin films may exist in tetragonal c-, orthorhombic aa-, monoclinic M-, and paraelectric PE phases. It is also found that the c-M and aa-PE phase boundaries exhibit a superior dielectric constant which reached 1.979 × 106 with um = −0.494%, as well as the c-M phase boundary showing a large piezoelectric response d15 which reached 1.64 × 105 pm/V. In comparison, the c-PE and M-aa phase boundaries exhibit a superior dielectric constant ε33 over 1 × 105 around um = 0.316% and the piezoelectric response d33 reached 7235 pm/V. The large electrocaloric responses appear near the paraelectric- ferroelectric phase boundary. These insights offer a guidance for experiments in epitaxial PIN–PMN–PT thin films. 相似文献
16.
Marc Behl Karl Kratz Ulrich Noechel Tilman Sauter Andreas Lendlein 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(31):12555-12559
Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to erasing this memory effect. Here temperature-memory polymer actuators (TMPAs) based on cross-linked copolymer networks exhibiting a broad melting temperature range (ΔTm) are presented, which are capable of a long-term temperature-memory enabling more than 250 cyclic thermally controlled actuations with almost constant performance. The characteristic actuation temperatures Tacts of TMPAs can be adjusted by a purely physical process, guiding a directed crystallization in a temperature range of up to 40 °C by variation of the parameter Tsep in a nearly linear correlation. The temperature Tsep divides ΔTm into an upper Tm range (T > Tsep) forming a reshapeable actuation geometry that determines the skeleton and a lower Tm range (T < Tsep) that enables the temperature-controlled bidirectional actuation by crystallization-induced elongation and melting-induced contraction. The macroscopic bidirectional shape changes in TMPAs could be correlated with changes in the nanostructure of the crystallizable domains as a result of in situ X-ray investigations. Potential applications of TMPAs include heat engines with adjustable rotation rate and active building facades with self-regulating sun protectors. 相似文献
17.
VO2, as a promising material for smart windows, has attracted much attention, and researchers have been continuously striving to optimize the performance of VO2-based materials. Herein, nitrogen-incorporated VO2 (M1) thin films, using a polyvinylpyrrolidone (PVP)-assisted sol–gel method followed by heat treatment in NH3 atmosphere, were synthesized, which exhibited a good solar modulation efficiency (ΔTsol) of 4.99% and modulation efficiency of 37.6% at 2000 nm (ΔT2000 nm), while their visible integrated transmittance (Tlum) ranged from 52.19% to 56.79% after the phase transition. The crystallization, microstructure, and thickness of the film could be regulated by varying PVP concentrations. XPS results showed that, in addition to the NH3 atmosphere-N doped into VO2 lattice, the pyrrolidone-N introduced N-containing groups with N–N, N–O, or N–H bonds into the vicinity of the surface or void of the film in the form of molecular adsorption or atom (N, O, and H) filling. According to the Tauc plot, the estimated bandgap of N-incorporated VO2 thin films related to metal-to-insulator transition (Eg1) was 0.16–0.26 eV, while that associated with the visible transparency (Eg2) was 1.31–1.45 eV. The calculated Eg1 and Eg2 from the first-principles theory were 0.1–0.5 eV and 1.4–1.6 eV, respectively. The Tauc plot estimation and theoretical calculations suggested that the combined effect of N-doping and N-adsorption with the extra atom (H, N, and O) decreased the critical temperature (τc) due to the reduction in Eg1. 相似文献
18.
19.
Chao Zhou Kaili Li Yuanliang Chen Zhiyong Dai Yu Wang Liqun Wang Yoshitaka Matsushita Yin Zhang Wenliang Zuo Fanghua Tian Adil Murtaza Sen Yang 《Materials》2022,15(11)
The magnetic morphotropic phase boundary (MPB) was first discovered in Laves-phase magnetoelastic system Tb–Dy–Co alloys (PRL 104, 197201 (2010)). However, the composition-dependent and temperature-dependent magnetostrictive behavior for this system, which is crucial to both practical application and the understanding of transitions across the MPB, is still lacking. In this work, the composition-dependence and temperature-dependence of magnetostriction for Tb1−xDyxCo1.95 (x = 0.3~0.8) are presented. In a ferrimagnetic state (as selected 100 K in the present work), the near-MPB compositions x = 0.6 and 0.7, exhibit the largest saturation magnetization MS and the lowest coercive field HC; by contrast, the off-MPB composition x = 0.5, exhibits the largest magnetostriction, the lowest MS, and the largest HC. Besides, a sign change of magnetostriction is observed, which occurs with the magnetic transition across the MPB. Our results suggest the combining effect from the lattice strain induced from structure phase transition, and the influence of the MPB on magnetocrystalline anisotropy. This work may stimulate the research interests on the transition behavior around the MPB and its relationship with physical properties, and also provide guidance in designing high-performance magnetostrictive materials for practical applications. 相似文献
20.
Tymon Warski Adrian Radon Przemyslaw Zackiewicz Patryk Wlodarczyk Marcin Polak Anna Wojcik Wojciech Maziarz Aleksandra Kolano-Burian Lukasz Hawelek 《Materials》2021,14(4)
The effect of substitution of Fe by Cu on the crystal structure and magnetic properties of Fe72−xNi8Nb4CuxSi2B14 alloys (x = 0.6, 1.1, 1.6 at.%) in the form of ribbons was investigated. The chemical composition of the materials was established on the basis of the calculated minima of thermodynamic parameters: Gibbs free energy of amorphous phase formation ΔGamorph (minimum at 0.6 at.% of Cu) and Gibbs free energy of mixing ΔGmix (minimum at 1.6 at.% of Cu). The characteristic crystallization temperatures Tx1onset and Tx1 of the alpha-iron phase together with the activation energy Ea for the as-spun samples were determined by differential scanning calorimetry (DSC) with a heating rate of 10–100 °C/min. In order to determine the optimal soft magnetic properties, the wound cores were subjected to a controlled isothermal annealing process in the temperature range of 340–640 °C for 20 min. Coercivity Hc, saturation induction Bs and core power losses at B = 1 T and frequency f = 50 Hz P10/50 were determined for all samples. Moreover, for the samples with the lowest Hc and P10/50, the magnetic losses were determined in a wider frequency range 50 Hz–400 kHz. The real and imaginary parts of the magnetic permeability µ′, µ″ along with the cut-off frequency were determined for the samples annealed at 360, 460, and 560 °C. The best soft magnetic properties (i.e., the lowest value of Hc and P10/50) were observed for samples annealed at 460 °C, with Hc = 4.88–5.69 A/m, Bs = 1.18–1.24 T, P10/50 = 0.072–0.084 W/kg, µ′ = 8350–10,630 and cutoff frequency at 8–9.3 × 104 Hz. The structural study of as-spun and annealed ribbons was carried out using X-ray diffraction (XRD) and a transmission electron microscope (TEM). 相似文献