Differing from the statically precipitated grain boundary α(GBα) that holds Burgers Orientation Relationship(BOR) with adjacent β grains, in this work, it was found that over 97.77 % of the dynamically precipitated...
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Differing from the statically precipitated grain boundary α(GBα) that holds Burgers Orientation Relationship(BOR) with adjacent β grains, in this work, it was found that over 97.77 % of the dynamically precipitated GBαs do not hold BOR with either side of the adjacent β grains in hot-forged Ti-652 titanium alloy. The evolution of GBα orientation was decoupled as dynamic precipitation and annihilation, which was quantitatively distinguished by defining three misorientation angles: the deviation form BOR(ω), the misorientation between adjacent β grains(θ) and the misorientation between non-BOR GBαs(θ'). During the entire hot forging, an adequate dynamic precipitation produces piecewise continuous and slender GBαs with ω <10°typically, manifesting as θ <25°but θ'>45°. Oppositely, a sufficient annihilation leads to the dynamic globularization of GBαs and increase of ω with θ≥25°but mainly θ'≤45°. Dynamic precipitation was driven by the intrinsic BOR preference of GBαs, while annihilation attributed to grain growth and rotation caused by accumulated plastic deformation. Deciphering the dynamic precipitation and annihilation of GBα provides a quantitative criterion to tailor microstructures and mechanical properties in the future.
This paper presents a systematic investigation of the microstructure and magnetocaloric properties of melt-extracted Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)high-entropy *** fabricated wires exhibited an amorphous structur...
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This paper presents a systematic investigation of the microstructure and magnetocaloric properties of melt-extracted Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)high-entropy *** fabricated wires exhibited an amorphous structure,and the temperature interval of the undercooled liquid AT was 45 *** microwires underwent a second-order magnetic transition from a ferromagnetic to a paramagnetic state near the Curie temperature(T_(C)=52 K),The maximum magnetic entropy change(-ΔS_M^(max)),the relative cooling power and the refrigeration capacity reached 6.34 J·kg^(-1)·K^(-1).422.09 J·kg^(-1)and 332.94 J·kg^(-1),respectively,under a magnetic field change of 5 *** addition,the temperature-averaged entropy changes with two temperature lifts(3 and 10 K)were 6.32 and 6.27 J·kg^(-1)·K^(-1),*** good magnetocalorie performance highlights the significant potential for the Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)microwires to be used as magnetic refrigerant materials in low-temperature region *** work will serve as a valuable reference for future investigations on low-temperature high-entropy magnetocaloric materials.
The stacking structure of Nb_(2)CSe_(2),a newly synthesized layered metal carbo-selenide,was elucidated by scanning transmission electron ***,CSe2 features Se-Nb-C-Nb-Se quintuple atomic *** layers are stacked in Bern...
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The stacking structure of Nb_(2)CSe_(2),a newly synthesized layered metal carbo-selenide,was elucidated by scanning transmission electron ***,CSe2 features Se-Nb-C-Nb-Se quintuple atomic *** layers are stacked in Bernal *** this mode,Nb,CSe2 crystallizes in a trigonal symmetry(space group P3m1,No.164),with lattice parameters of a=3.33 A and c=18.20 *** structure calculations indicate that the metal carbo-selenide has Fermi energy crossing the bands where it touches to give a zero gap,indicating that it is an electronic *** evidenced experimentally,the electrical conductivity is as high as 6.6×10^(5) S·m^(-1),outperforming the counterparts in the MXene *** to the layered structure,the bonding in Nb_(2)CSe_(2) with an ionic formula of(Nb^(1.48+)),(C^(1.74-))(Se^(0.61-))_(2) is highly anisotropic,with metallic-covalent-ionic bonding in intralayers and weak bonding between *** layered nature is further evidenced by elastic properties,interlayer energy,and friction coefficient *** characteristics indicate that Nb_(2)CSe_(2) is an analog of molybdenum disulfide(MoS_(2)),which is a typical binary van der Waals(vdW)***,vibrational properties are reported,which may offer an optical identification standardfor new ternary vdW solids in spectroscopic studies,including Raman scatteringand infrared absorption.
High intraocular pressure(IOP) is one of the high-risk pathogenic factors of glaucoma. Existing methods of IOP measurement are based on the direct interaction with the cornea. Commercial ophthalmic tonometers based on...
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High intraocular pressure(IOP) is one of the high-risk pathogenic factors of glaucoma. Existing methods of IOP measurement are based on the direct interaction with the cornea. Commercial ophthalmic tonometers based on snapshot measurements are expensive, bulky, and their operation requires trained *** contact lenses are easy to use, but they may block vision and cause infection. Here, we report a sensory system for IOP assessment that uses a soft indentor with two asymmetrically deployed iontronic flexible pressure sensors to interact with the eyelid-eyeball in an eye-closed situation. Inspired by human fingertip assessment of softness, the sensory system extracts displacement-pressure information for soft evaluation, achieving high accuracy IOP monitoring(>96%). We further design and custom-make a portable and wearable ophthalmic tonometer based on the sensory system and demonstrate its high efficacy in IOP screening. This sensory system paves a way towards cost-effective, robust, and reliable IOP monitoring.
With the further requirements of electronic products and powered vehicles,the development of a new generation with low-voltage and high-capacity anode materials is crucial for lithium-ion batteries(LIBs).Transition me...
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With the further requirements of electronic products and powered vehicles,the development of a new generation with low-voltage and high-capacity anode materials is crucial for lithium-ion batteries(LIBs).Transition metal phosphides,especially cobalt phosphide(CoP)composites,have become a research hotspot for LIBs anode materials in recent years due to their high theoretical specific capacity,low polarization,and suitable voltage *** review first systematically discusses the lithium storage mechanism and preparation methods of CoP in current ***,the applications of CoP anode materials in LIBs are categorically reviewed,including the composites of CoP with various types of carbon materials and ***,the challenges and future development directions of CoP anode materials are summarized to provide guidance for further improving the lithium storage performance of CoP and its practical applications.
As the main component of wearable electronic equipment,flexible pressure sensors have attracted wide attention due to their excellent sensitivity and their promise with respect to applications in health monitoring,ele...
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As the main component of wearable electronic equipment,flexible pressure sensors have attracted wide attention due to their excellent sensitivity and their promise with respect to applications in health monitoring,electronic skin,and human-computer ***,it remains a significant challenge to achieve epidermal sensing over a wide sensing range,with short response/recovery time and featuring seamless conformability to the skin *** is critical since the capture of minute electrophysiological signals is important for health care *** this paper,we report the preparation of a nacre-like MXene/sodium carboxymethyl cellulose(CMC)nanocomposite film with a“brick-and-mortar”interior structure using a vacuum-induced self-assembly *** synergistic behavior of the MXene“brick”and flexible CMC“mortar”contributes to attenuating interlamellar self-stacking and creates numerous variable conductive pathways on the sensing *** resulted in a high sensitivity over a broad pressure range(i.e.,0.03-22.37 kPa:162.13 kPa^(-1);22.37-135.71 kPa:127.88 kPa^(-1);135.71-286.49 kPa:100.58 kPa^(-1)).This sensor also has a low detection limit(0.85 Pa),short response/recovery time(8.58 ms/34.34 ms),and good stability(2000 cycles).Furthermore,we deployed pressure sensors to distinguish among tiny particles,various physiological signals of the human body,space arrays,robot motion monitoring,and other related applications to demonstrate their feasibility for a variety of health and motion monitoring use cases.
Mechanical properties of polymers can be regulated by changing the numbers of hydrogen bonds and entanglement ***,the interplay between hydrogen bond network and entangled network during stretching has not been fully ...
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Mechanical properties of polymers can be regulated by changing the numbers of hydrogen bonds and entanglement ***,the interplay between hydrogen bond network and entangled network during stretching has not been fully *** performed molecular dynamics simulations to investigate the changes of hydrogen bonds and entanglements during *** stretching causes the orientation of local segments,leading to the entanglement sliding and disentanglements at different strain ***,the number of entanglement points keeps constant at first and then decreases with increasing ***,the orientation of local segments can cause the change of chain conformation,which leads to the breakage of hydrogen ***,the number of hydrogen bonds decreases with the increase of *** results also demonstrated that the number of hydrogen bonds decreases faster during stretching in systems containing more *** systems with different hydrogen bond site contents,the initial number of entanglement nodes and its decline range during stretching increase firstly and then decrease with the increase of hydrogen bond site content.
Metal dichalcogenide-based 2D materials,gained considerable attention recently as a hydrogen evolution reaction（HER） *** this work,we synthesized MoSe2-based electrocatalyst via hydrothermal route with varying phase...
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Metal dichalcogenide-based 2D materials,gained considerable attention recently as a hydrogen evolution reaction（HER） *** this work,we synthesized MoSe2-based electrocatalyst via hydrothermal route with varying phase contents（1T/2H） and respective HER performances were evaluated under the acidic media（0.5 M H2SO4）,where best HER performance was obtained from the sample consisting of mixed 1T/2H phases,which was directly grown on a carbon paper(167 mV at10 mA cm-2) Furthermore,HER performance of electrocatalyst was further improved by in-situ electrodeposition of Pt nanoparticles（0.15 wt%） on the MoSe2 surface,which lead to significant enhancement in the HER performances(133 mV at 10 mA cm-2).Finally,we conducted density functional theory calculations to reveal the origin of such enhanced performances when the mixed 1T/2H phases were present,where phase boundary region（1T/2H heterojunction） act as a low energy pathway for H2adsorption and desorption via electron accumulation ***,presence of the Pt nanoparticles tunes the electronic states of the MoSe2based catalyst,resulting in the enhanced HER activity at heterointerface of 1T/2H MoSe2 while facilitating the hydrogen adsorption and desorption process providing a low energy pathway for *** results provide new insight on atomic level understanding of the MoSe2based catalyst for HER application.
Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation proce...
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Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation process for the coating of carbonyl iron powder(CIP) with TiO_(2) was designed. Given the TiO2coating, the Z of the CIP@TiO_(2) composite was adjusted well by decreasing the dielectric constant. Moreover, the interfacial polarization of CIP@TiO_(2) was enhanced. Ultimately, the electromagnetic-wave (EMW) absorption property of the CIP@TiO_(2)composite was improved substantially, the minimum reflection loss reached-46.07 dB, and the effective absorption bandwidth can reach 8 GHz at the composite thickness of 1.5 mm. Moreover, compared with CIP, the oxidation resistance of CIP@TiO_(2)showed remarkable improvement. The results revealed that the oxidation starting temperature of CIP@TiO_(2) as about 400℃,whereas the uncoated CIP had an oxidation starting temperature of approximately 250℃. Moreover, the largest oxidation rate temperature of CIP@TiO_(2) increased to around 550℃. This work opens up a novel strategy for the production of high-performance EMW absorbers via structural design.
Aqueous zinc-sulfur batteries at room temperature hold great potential for next-generation energy storage technology due to their low cost,safety and high energy ***,slow reaction kinetics and high activation energy a...
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Aqueous zinc-sulfur batteries at room temperature hold great potential for next-generation energy storage technology due to their low cost,safety and high energy ***,slow reaction kinetics and high activation energy at the sulfur cathode pose great challenges for the practical ***,biomass-derived carbon with single-atomic cobalt sites(MMPC-Co)is synthesized as the cathode in Zn-S *** catalysis of single-atom Co sites greatly promotes the transform of cathode electrolyte interface(CEI)on the cathode surface,while offering accelerated charge transfer rate for high conversion reversibility and large electrochemical surface area(ECSA)for high electrocatalytic ***,the rich pore structure not only physically limits sulfur loss,but also accelerates the transport of zinc *** addition,the large pore volume of MMPC-Co is able to relieve the stress effect caused by the volume expansion of Zn S during charge/discharge cycles,thereby maintaining the stability of electrode ***,the sulfur cathode maintains a high specific capacity of 729.96 m A h g^(-1)after 500 cycles at4 A g^(-1),which is much better than most cathode materials reported in the *** work provides new insights into the design and development of room-temperature aqueous Zn-S batteries.
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