JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Shijie Xu,Huimin Zhang,Bige Qiao,Yanfei Wang
Currently, how the solvents and temperature affect the solution species and rate-determining step in the nucleation process, thus altering the nucleation behavior remains elusive. In this contribution, by employing metastable zone width (MSZW) experiments, the modified Sangwal’s theory and the molecular dynamic simulations, we explore nucleation behavior of benzoic acid (BA) in polar and non-polar solvents. We find that in methanol, the solid–liquid interfacial tension γ decreases with increasing the saturation temperature, in contrast, the value of γ increases with increasing the saturation temperature in chloroform. Furthermore, in the classical nucleation framework, we conclude that the critical nuclei size and critical Gibbs free energy monotonous decline as the driving force increases in methanol, which implies that the interfacial tension is independent of the driving force. On the contrary, the relationship between critical nucleation parameters and driving force indicates that the interfacial tension changes with the driving force in chloroform. By employing FTIR, we find that dimerization of BA is restricted in methanol, and BA always exists as the monomer even near the nucleation point, which implies that desolvation is the rate-determining step in the nucleation process. While in chloroform, we demonstrate that the form of monomers and dimers coexist in solution. As the saturation temperature increases, the equilibrium is broken and moves toward the monomer. It implies that the rate-determining step of the nucleation process of BA may change from molecular rearrangement to desolvation with increasing the saturation temperature in chloroform.
研究领域:
物理化学
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材料科学
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DOI
高影响因子
IEEE Transactions on Components Packaging and Manufacturing Technology
·
2024
·Vol. 14
·期 1
·10-17
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IF 2.3
Bowen Zhang,Xinyan Lu,Haoxiang Ma,Di Wang,Yun-Hui Mei
The spontaneous aggregation and weak stability of nanosilver particles largely overshadowed the application of nanosilver paste as die-attach materials in wide bandgap (WBG) devices. Taking advantage of the self-decomposition of silver-ammonia complexes to form silver particles, a novel particle-free silver paste was successfully developed to achieve higher sintering driving force as well as bonding quality. The proposed silver paste not only promotes the decomposition of silver complex but also reduces the oxygen requirement during the decomposition process, which significantly increases the shear strength from 23.8 to 59.4 MPa. The crystallization behavior and microstructure evolution confirm that the temperature required for the formation of silver particles in the proposed silver paste was reduced to 150 °C. At the same time, the necking growth also occurred at the low temperature of 150 °C, which is much lower than previous research and successfully confirms the higher sintering driving force of the proposed silver paste. More importantly, the proposed sintered silver paste exhibited high thermal stability, and the overall shear strength degradation was only 29.5% after 1000 cycles of thermal shock test (TST). The high sintering driving force combined with the high thermal reliability of the proposed silver-complex paste enables the development of high-performance WBG semiconductors with superior mechanical and electrical properties.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2023
·Vol. 54
·期 4
·1675-1686
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IF 3
Fu Yingzheng,Zhang Zhimin,Lu Xuchen,Yan Yan,Pan Binfeng
To increase the reaction driving force and prepare Mg–Nd master alloys, the synergistic interaction between NdCl 3 and NdF 3 was used in the magnesiothermic reduction process in NdCl 3 –NdF 3 -containing molten salt. Thermomechanical analysis was used to investigate the possibility of the synergistic interaction in molten salt. Then the verification of synergistic interaction was conducted by analyzing the composition of the molten salt and the alloys obtained in the magnesiothermic reduction process. After that, the factors affecting synergistic interaction were investigated. At last, the mechanism of the synergistic interaction between NdCl 3 and NdF 3 in molten salt was proposed and discussed. The coupling reaction formed in the magnesiothermic reduction process and the existence of three reaction mechanisms increased the reaction driving force. Mg–RE master alloys with the content of Nd being 25 to 30 wt pct were prepared under the optimum conditions and the conversion rate of NdF 3 was greater than 70.94 pct. The content of Nd and the content of various impurities in the alloys obtained both met the requirements of the commercial Mg–Nd master alloys.
研究领域:
材料科学
·
冶金学
·
化学工程
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DOI
高影响因子
ACS Nano
·
2023
·
IF 17.1
Ying Lu,Yiwei Huang,Zihan Xu,Kaichuang Yang,Weichao Bao,Qiyang Lu
Metal nanoparticles exsolved and anchored at the parent perovskite oxide surfaces can greatly enhance the activity and antisintering stability for high-temperature (electro-) chemical catalytic reactions. While exsolution of nanoparticles triggered by using conventional high-temperature thermal reduction suffers from slow kinetics, using an electrochemical driving force can promote the exsolution rate. However, a quantitative correlation between the applied electrochemical driving force and the spatial density of exsolved nanoparticles remains unknown. In this work, we use a specially designed electrochemical device to induce a spatially graded voltage in a La0.43Ca0.37Ti0.94Ni0.06O3−δ electrode, in order to systematically investigate the effect of electrochemical switching on exsolution. With increasing driving force, which leads to decreasing oxygen chemical potential, the density of nanoparticles was observed to increase dramatically, while the average particle size remained roughly constant. We further identified oxygen vacancy pairs or clusters as the preferential nucleation sites for exsolution. Our work provided a high-throughput platform for the systematic study of exsolution of perovskite oxides targeted for fuel electrode materials with improved electrocatalytic performance and stability.
研究领域:
材料科学
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电化学
·
催化
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
·
IF 10.53
Zhan Gao,Xia Gu,Caini Liu,Zilai Zhang,Huaiqi Shao,Qingbo Zhang,Mingce Long,Xiaoyan Guo
The inefficient separation of water-in-oil emulsions through conventional techniques and the troublesome membrane fouling of membrane technology call for alternative efficient and antifouling membrane separation approaches to meet the increasing demands for global environmental protection and energy recovery. Here, we demonstrate an internal electrostatic force-driven superoleophilic membrane-magnetic particles coupling system enabling water-in-oil emulsions super-efficiently separated. Specifically, as-prepared magnetic nanoparticles significantly facilitate the separation of water-in-oil emulsions due to their superoleophilic behaviors and electrostatic repulsion forces between the magnetic nanoparticles-encapsulated Pickering emulsions . Furthermore, the magnetic nanoparticles incorporate into the membrane to increase the roughness and superoleophilic ability, distinctly leading to superefficient separation capacity for water-in-oil emulsions. Meanwhile, their separation performances are so stable that remarkably outperform other membrane systems during 10-cycle operation owing to the enhanced antifouling efficacy, under the support of electrostatic repulsion forces caused by the magnetic nanoparticles-modified composite membrane and magnetic nanoparticles-encapsulated Pickering emulsions. Hence, the combination of the electrostatic repulsion forces and interfacial forces render the as-constructed superoleophilic membrane-magnetic nanoparticles coupling system dramatically exhibit a remarkably high separation flux of 8.76 × 10 4 L m −2 h −1 bar −1 for the water-in-toluene emulsion under the conditions of pH of 10 and sodium dodecyl sulfate surfactant , considerably higher than the existing reports of the state-of-the-art membranes. This study will open up new avenues for superefficient and stable separation of water-in-oil emulsions in actual situations, and this concept will be promising for extending to other oil-in-water emulsions and oily waste water treatment.
研究领域:
环境工程
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材料科学
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化学工程
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纳米技术
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Bo-liang Wu,Yu-chen Peng,Hong-qun Tang,Yong-zhong Zhan,Feng-lin Zhang
Nanodiamond (ND) has been recently considered to be an excellent reinforcement for strengthening metal matrix composites . However, most of the previous studies focused on manufacturing process, final structure, and mechanical properties . Systematic exploration of the microstructural evolution , which is critical to understand the effect mechanism of ND particles, still lacks. Herein, we seek to understand the effect of ND particles on microstructural evolution via comparative investigation of microstructures in different test points on extrusion remnant specimens of pure aluminum , 0.5 wt% and 1.0 wt% ND-reinforced aluminum composites prepared by powder metallurgy and hot extrusion. Finite element simulations were used to analyze the relative stress–strain states and deformation modes in different test points. Electron backscatter diffraction and transmission electron microscopy studies reveal that the mean grain size of ND-reinforced aluminum composite declined rapidly after entering the extrusion deformation zone. Microstructures in simple shear, tensile pure shear, and compressive pure shear deformation modes were quite different. The dispersed ND particles effectively promoted grain refinement and improved dislocation driving force with the increase in plastic strain. The large localized high-content ND clusters were broken into small ones, and small ones acted as non-deformable particles to stimulate nucleation and recrystallization under high dislocation driving force. Test results show that the hardness of 0.5 wt% and 1.0 wt% ND-reinforced aluminum composites was 1.9 and 2.1 times that of pure aluminum, respectively. The 0.5 wt% ND-reinforced aluminum composites exhibited optimal comprehensive mechanical properties with a tensile strength of 205 MPa and elongation of 18%, which were 115% and 91% of pure aluminum, respectively.
研究领域:
材料科学
·
机械工程
·
冶金学
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产品关联
DOI
高影响因子
CELLULOSE
·
2023
·
IF 5.7
Yang Junjie,Wang Siyong,Yao Jintong,Jiang Zhen,Fang Mingjian,Yu Tao,Wei Kang
This study focuses on investigating a novel category of paper actuators, aiming to attain a favorable equilibrium between substantial electrically actuated force and extended service lifetime ( T s ) for the soft electric-responsive artificial muscle. Consequently, the present research has developed an Electro-responsive Biomass Paper Actuator (ERBPA) utilizing calcium alginate hydrogel, employing absolute ethanol (CH 3 CH 2 OH) as the slow-release agent, through a straightforward and viable preparation procedure. Moreover, a comprehensive investigation was carried out on the electro-mechano-chemical behaviors and strengthening mechanism of the ERBPA with varying volume fractions of CH 3 CH 2 OH, under the electrical actuation of 4 V DC voltage. The experimental findings revealed a gradual decrease in the density of electrically actuated force, elastic modulus, and yield strength with the increasing volume fraction of CH 3 CH 2 OH. Specifically, at a volume fraction of 30%, these properties reached their respective minimum values of approximately 15.152 mN/g, 6.5 MPa, and 0.0999 MPa. In contrast to the internal resistance ( R g ) of the ERBPA, the specific capacitance ( C p ) and the T s exhibited an initial improvement followed by a reduction, while the rise time ( T r ) demonstrated a positive correlation with the volume fraction of CH 3 CH 2 OH but a negative correlation with the reaction velocity ( V f ). Specifically, at a volume fraction of 25%, C p , T s and T r reached their maximum values of 96.2 mF/g, 1287 s, and 170 s, respectively, whereas R g and V f attained their minimum values of 2.39 Ω and 0.044 mN/g·s, respectively. The slow-release effect of CH 3 CH 2 OH inherently contributed to the protection of certain free Ca 2+ ions, thereby causing a gradual and consistent coordination process with sodium alginate molecules. This, in turn, greatly enhanced the internal structure of ERBPA, resulting in exceptional T s stability and operational performance.
研究领域:
材料科学
·
电化学
·
机械工程
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2024
·
IF 10.7
Riting Huang,Furui He,Shujuan Yang,Keyang Mai,Shuntian Huang,Haifang Liu,Yuhong Feng,Gaobo Yu,Jiacheng Li
High quantum yield polysaccharide-based materials are significative for the dynamic anti-counterfeiting, while that are limited by weak fluorescence. However, natural polysaccharides with weak fluorescence are not suitable for anti-counterfeiting. Herein, alginate derivatives (SA-PBA) exhibiting aggregation-induced emission with high-quantum yields were synthesized by grafting phenylboronic acid (PBA) onto a sodium alginate (SA) chain. As the concentration increases, polymer assembly can be induced to form more compact soft colloidal aggregates, which enhances the fluorescence properties of alginate derivatives by introducing B ← N coordination bonds in the hydrophobic microregions. Interestingly, the clustered aggregates of SA-PBA can be dynamically controlled by pH, realizing the reversible adjustment of fluorescence. The corresponding mechanism is revealed by the combination of coarse-grained simulations and experiments. It is found that SA-PBA uses a hydrophobic driving force and hydrogen bond interaction to self-assemble in an aqueous solution and promote fluorescence emission. Moreover, the fluorescence quantum yield of SA-PBA can reach 14.4 % and can be reversibly altered by tuning soft colloidal microstructures. Therefore, a reversible information encryption system of SA-PBA is developed for anti-counterfeiting. This work shed some light on how to design novel anti-counterfeit materials based on natural polysaccharides and optimize the dynamic fluorescence conditions.
研究领域:
材料科学
·
化学
·
纳米技术
·
防伪技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）