CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Rui Jia Liu,Ling Xu Yang,Ying Wang,Hui Jun Liu,Sheng Long Zhu,Chao Liu Zeng
High-purity ternary layered carbide V 2 AlC powders have been prepared by a two-step modified molten salt method, i.e. by firstly synthesizing V 2 C with V and C powders at 900 °C, followed by preparing V 2 AlC with V 2 C and Al powders as reactants at 900–950 °C in molten (Na,K)Cl. The average particle distribution of V 2 AlC powders was estimated to be ~400 nm. Molten salt as a reaction medium could promote the synthesis of V 2 C and V 2 AlC at lower temperatures. The synthesizing mechanisms of V 2 C and V 2 AlC in molten salts have also been discussed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2024
·
IF 3.1
Hailong Zhou,Jiuyu Chen,Yunlan Sun,Naiqiang Huang,Jiang Liu,Xuan Jiang,Baozhong Zhu
Boron (B) powder has been considered a promising high-energy material due to its high calorific value. Nevertheless, the low combustion efficiency and the difficulty in ignition restrict its application. To solve the problems, in this study, an energetic metal-organic framework (EMOF) was used as a modifier for the nano-sized B powder, and its effect on the ignition and burning performance of B powder was examined. EMOF can significantly increase the heat release of B powder and lower its initial oxidation temperature. The best improvement is achieved with 10% EMOF contents in air, while the highest heat release is obtained with 25% EMOF contents in pure oxygen. Furthermore, EMOF can also reduce the ignition delay of B powder, enhance the flame intensity, and increase the flame propagation rate. This study offers new perspectives on modifying B powder with incorporating EMOF to develop multifunctional energetic particles with improved ignition and combustion characteristics.
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 11
·11126-11139
·
IF 2.914
Li Zhenyuan,Pan Zhidong,Wang Yanmin
A raw illite-smectite mixed-layered clay (RI/S) was ground for preparing nano-sized I/S clay (NI/S) and subsequently amino-functionalized via grafting of 3-aminopropyltrithoxysilane (APTES) (NH 2 -RI/S and NH 2 -NI/S, respectively). The samples were characterized by particle size analysis, specific surface area measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and 29 Si nuclear magnetic resonance ( 29 Si NMR). Compared to RI/S, NI/S has a narrow particle size distribution and appears in a platelet-like morphology due to the disintegration/exfoliation of RI/S after grinding. Based on the 29 Si NMR spectra, the appearances of tri-silicate units indicate the chemically grafting of APTES molecules on NH 2 -RI/S and NH 2 -NI/S, respectively. NH 2 -NI/S can adsorb greater amounts of Pb(II) cations and Cr(VI) anions rather than NH 2 -RI/S since NH 2 -NI/S grafts more amounts of amine groups (-NH 2 ). The isotherm data for adsorption of Pb(II) cations and Cr(VI) anions can be described by the Langmuir model at different temperatures (i.e., 10 °C, 30 °C, and 50 °C), respectively. The maximum adsorption amounts of Pb(II) cations and Cr(VI) anions onto NH 2 -NI/S calculated by the Langmuir isotherm model are 131.23 mg/g and 36.91 mg/g at 50 °C, respectively. The adsorptions of Pb(II) cations and Cr(VI) anions onto NH 2 -NI/S involve in the surface complexation of NI/S and amine groups.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanoscience and Nanotechnology Letters
·
2017
·Vol. 9
·期 2
·123-133
·
IF 1.889
Sha Ruyi,Wu Yuanyuan,Cai Chenggang,Mao Jianwei,Liu Shiwang,Wang Wenxing
Garlic oil has been shown to have many pharmacological and biological activities. However, its poor solubility in water, volatility and instability limit its extensive application in the fields of medicine, cosmetics and food. In this work, nanoscale garlic oil microemulsions were prepared
with canola oil, a canola oil/garlic oil mixture or pure garlic oil as the oil phase, Tween-80 as the surfactant and ultrapure water as the aqueous phase, and the microemulsions were characterized. The influence of the co-surfactant type (glycerol, ethanol and n-butanol) and the mass
ratio of the surfactant to the co-surfactant (K
m) in the oil-in-water (O/W), water-in-oil (W/O), and binary continuous phase (BC) microemulsion regions in pseudoternary phase diagrams were investigated. Moreover, the antioxidant activity of the prepared garlic oil microemulsion
was evaluated. The results showed that when ethanol was used as a co-surfactant, a canola oil monophase microemulsion area of 42.03% can be obtained at a K
m of 2:1 with a particle size of 88.44 nm, and the monophase microemulsion area was approximately 18.55% and 52.54% for
the canola oil/garlic oil mixture as the oil phase at the mass ratios of 10:1 and 5:1, respectively, with a mean particle diameter of 13.33∼14.00 nm. The results also suggested that when using ethanol as the co-surfactant at a K
m of 3:1, the garlic oil monophase microemulsion
area of 52.54% and an O/W microemulsion area of 16.62% could be produced with a size of approximately 15.0 nm. Furthermore, the results showed that a microemulsion of garlic oil/Tween-80/ethanol/water exhibited remarkable antioxidant activity against the superoxide anion, hydroxide radical
and hydrogen peroxide using chemiluminescence methods, with IC50 values of 17.98 mg/mL, 4.17 mg/mL and 8.47 mg/mL, respectively. This study suggested that garlic oil microemulsions may be a promising dispersion for use in food and pharmaceutical products.
研究领域:
食品科学
·
药学
·
生物学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Baiyun Cheng,Qilai Zhou,Shengming Yin,Kaixuan Zhu,Yasuhisa Oya
Lithium ceramics are regarded as potential candidates for tritium breeding in fusion reactors. Lead (Pb) was added to the ceramic to improve the strength and tritium release properties. The Li 2 TiO 3 -0.5Li 4 SiO 4 –Pb ceramic powders with the Pb contents of 5 wt% and 20 wt% were prepared by microwave-induced solution combustion synthesis . It was confirmed that the Pb was in the form of the Li 2 PbO 3 phase in the powders. The Li 2 TiO 3 , Li 4 SiO 4 , and Li 2 PbO 3 crystallites were composited at nanoscale level, which was confirmed by the transmission electron microscopy (TEM). During high-temperature sintering, the Li 2 PbO 3 was transformed into PbO, which facilitated the densification process at low temperatures. The chemical state in the sintered body was characterized by X-ray photoelectron spectroscopy (XPS) with 3 keV Ar + sputtering. The binding energies for Pb were 137.2 and 142.2 eV. There was almost no change in peak position during Ar + sputtering, showing that Pb was firmly adherent with oxygen atoms. Besides, the as-synthesized powders were used for the pebble fabrication. The average crush load of Li 2 TiO 3 -0.5Li 4 SiO 4 –20%Pb pebbles sintered at 1223 K was 124 N, which was much higher than that without Pb addition. It was proved that the crush load increased almost linearly with the increase in the size of the pebbles. Thus, the bending strength of the sintered ceramic body was used to evaluate the mechanical properties. Further, the grain growth kinetics was studied. It was confirmed that the Pb addition reduced the activation energy of grain growth, which realized the densification of the ceramic pebbles at low temperatures.
研究领域:
材料科学
·
核能工程
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2024
·Vol. 11
·期 5
·1596-1606
·
IF 6.1
Dehua Wang,Minghui Mo,Man Xu,Zhijun Xia,Xuebin Zhao,Beibei Gao
Seed-assisted synthesis of nano-SAPOs usually requires a costly nano-sized seed, and the micron-sized seed used should be ball-milled or treated under reflux to broke them into nano-particles. In this study, nano-sized SAPO-34 was prepared using a micron-meter SAPO-34-M seed that was treated facilely with morpholine (MOR) within a Teflon-lined stainless steel autoclave to obtain a seed solution. As MOR was also the template for SAPO-34 synthesis, no extra template was added to the precursor gel. The effects of MOR treatment time on seed properties and the subsequent SAPO-34 fabrication were characterized via XRD, SEM, N2 adsorption–desorption, 29Si NMR and NH3-TPD techniques. The effect of the seed amount on the products was also investigated. There existed optimum seed treatment time and seed addition amount for synthesizing uniform nano-sized SAPO-34 with the characteristics of larger mesopore volume, lower Si contents and acid density and weaker acid strength than conventional SAPO-34. Moreover, heterologous seed-assisted syntheses of SAPO-34 were carried out, and it is found that micron-sized heterologous seeds (AFI, RHO, LEV and AFX) treated with MOR can also deliver nano-sized SAPO-34, although AFI and RHO share no common composite building units (CBUs) with CHA, suggesting that seed selection in this synthesis strategy is not confined to a specific topology. The obtained nano-sized SAPO-34 catalysts exhibited about a 2.7-fold prolonged lifetime and nearly 5% increased selectivity for ethylene and propylene compared to their conventional micron-sized counterparts in methanol-to-olefin (MTO) reactions.
研究领域:
材料科学
·
催化化学
·
能源化学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 10
·期 3
·835-843
·
IF 5.726
Yan Zhang,Shide Wu,Xia Xu,Heqing Jiang
Rapid deactivation by coke deposition is the main obstacle of ethane aromatization over Zn/ZSM-5. In this work, using the prepared nanosized Zn/HZSM-5, an almost threefold product yield and significantly improved stability were achieved in comparison with those of the microsized catalyst. XRD and XPS analyses indicated that a higher percentage of reactive [ZnOZn]2+ species was maintained during ethane aromatization over nano-Zn/HZSM-5 than micro-Zn/HZSM-5. In addition, the evolution of carbon deposits over nanosized and microsized Zn/ZSM-5 was investigated during prolonged ethane aromatization reaction using Raman spectroscopy and thermogravimetry measurements. Compared to the microsized catalyst, the nanosized zeolite facilitated the faster escape of light aromatics and the precursors of carbon deposits from the zeolite pores, thus suppressing the accumulation of coke deposits and improving the catalyst stability. Based on the nanosized Zn/HZSM-5, a protocol of isothermal reaction followed by regeneration was developed by periodically removing carbonaceous deposits, and an ∼25–35% product yield was achieved after 10 reaction–regeneration cycles.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
Advanced Science
·
2023
·Vol. 10
·期 19
·2301170
·
IF 15.1
Yifan Wang,Jiarong Niu,Xin Jin,Xiaoming Qian,Changfa Xiao,Wenyu Wang
Electromagnetic (EM) metamaterial is a composite material with EM stealth properties, which is constructed by artificially reverse engineering metal split resonance rings (SRR). However, the greatest limitation of EM metamaterials is that they can only stealth at a fixed and lower frequency of EM waves, and modern processing techniques still cannot meet the accuracy requirements to fabric nano-size structural unit. Nano-sized and even ultra-small SRR at molecular level are promising arrays to realize the ability of EM stealth function at a higher frequency, although it has proven challenging to synthesize long, straight, connected molecular SRR, and also difficult to arrange those molecular SRR into a strict array. Here, the study overcomes this challenge and demonstrates that the fabric of polypyrrole molecular SRR achieves an ultra-small inner diameter of 2.49 Å and realizes the arrays arrangement at molecular level. Furthermore, the study exploits the EM stealth function and verifies that such arrays of molecular SRR with 2.49 Å have the ability to reach high-performance EM stealth in the range of 10 6 –10 16 Hz. This design concept opens a pathway for developing new metamaterials with broadband EM wave stealth and also serves the wider range of new applications.
研究领域:
材料科学
·
电磁学
·
纳米技术
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Zhiqiang Li,Shiguang Yan,Jiake Xia,Fei Cao,Xuefeng Chen,YunXiong Song,Yonghong Chen,Zhi-Sheng Lin,Genshui Wang
With the increasing demand for the miniaturization, high capacitance and high reliability of the Multilayer Ceramic Capacitor (MLCC), the thickness of single dielectric layer is less than 1 μm and the original partical size of the powder has reached the scale less than 300 nm. In this paper, BaTiO 3 powder of various partical sizes (150–500 nm) was modified with Dy and Ho through a chemical coating method. The dense and uniform ceramics in accordance with EIA X7R-type temperature stability were sintered under low oxygen partial pressure and good dielectric properties of dielectric constant >2000 and dielectric loss <1% were obtained. The grain size effect on the dielectric properties under various dc-bias field were systematically investigated. It is found that the fine-grain ceramic exhibits a lower absolute change of the dielectric constant and a higher dc-bias stability. Furthermore, the modified 150 nm BaTiO 3 powders was made into 1210-type MLCCs, and the dielectric behavior of the MLCCs with different dc-fields and ac-fields were study over −55 °C–125 °C. It is found that the ac electric field had a greater influence on the dielectric properties at room temperature and below, and the dielectric constant variation under a dc-bias field was also greatly advanced for the modified fine-grain MLCCs. The results provide a reference for the design of the next generation of BME-MLCCs.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2021
·
IF 4.837
Man-Yu Qian,Ji-Huan He
A critical hurdle in membrane fabrication is the threshold thickness, beyond which the artificial membrane becomes impossible. In contrast, biological membranes have a nanoscale thickness, enabling their excellent permeability and remarkably perfect selectivity . We address this challenge by designing a novel bubble spinning process that can produce nanoscale members instead of nanofibers from polymer bubbles. The process herein is to enlarge the bubble so that the thickness of the bubble wall is only a few tens of nanometers. The fragments of the broken bubbles are received on a mesh receptor, and an artificial membrane with nanoscale thickness is obtained. This process sheds a bright light on the biomimetic fabrication of nanoscale membranes. Moreover, although our work focuses on the mechanism, we anticipate that the bubble spinning can be used for large-scale fabrication of natural-inspired extremely thin membranes with good permeability and ideal selectivity, and other functions.
研究领域:
材料科学
·
生物仿生学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhubin Yao,Jiekai Xie,Tieqiang Fu,Yunjun Luo,Xiaoqing Yang
Mainstream phase change material (PCM) for the thermal management of battery modules has been suffering from the leakage issue due to the weak capillary condensation from its micron-scaled polymer framework. Therefore, in this work, we design a high-stable and leakage-proof composite PCM (CPCM) by in-situ constructing a nano-scaled resorcinol-furfural polymer framework (RF-PF) in PCM via a one-pot strategy. Compared to classical micron-scaled framework of epoxy resin, the nano-scaled RF-PF stacks into a three-dimensionally mesoporous structure, and thus provides a much more intensive adsorbability towards PCM to prevent leakage. The mass retention rate of the RF-PF-based CPCM (RF-CPCM) during the leakage tests is up to 99.84 wt%. Combining with the suitable thermo-physical properties including a phase change enthalpy of 107.18 J g −1 , phase change temperature region of 40– ∼ 55 °C and thermal conductivity of 1.58 W m −1 K −1 , the RF-CPCM demonstrates effective and stable thermal management performances towards the pouch and cylindrical battery modules. For example, the temperature of the pouch battery module can be controlled below 41.15, 44.16 and 46.82 °C during 0.5-C, 1-C and 2-C discharges, respectively. During the accelerated aging test, the leakage trace appearing on the traditional CPCM module, is effectively overcome in the RF-CPCM module.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2018
·
IF 6.036
Xin Liang,Lei Shen
Grain boundary plays an important role in energy carrier transport. By choosing ZnO as a model system of technological importance, and by measuring the thermal and electrical transport properties of ZnO polycrystals with a wide range of grain boundary spacing, we determine the interfacial thermal (Kapitza) resistance of the ZnO grain boundary R k = 4.0 ± 0.7 × 10 − 9 m 2 K W −1 , which is relatively independent of grain size . The effective electron potential barrier height and the depletion width of the grain boundary generally increase with spacing, but they collapse below ∼100 nm and become almost invariant above ∼1 μm. When the grain boundary is locally modified by nanometer-thick ZnS thin film , the Kapitza resistance increases by more than three times, up to about 12.9 × 10 − 9 m 2 K W −1 , and the depletion region expands more than twice. The charge carrier concentration is influenced by the effective potential barrier height due to the grain boundary energy filtering effect whereas the electron mobility is related to the depletion width. Our investigations demonstrate the significance of grain boundary characteristics for interfacial and effective bulk transport properties. The findings and the approach are broadly important for polycrystalline materials of which the functional performance can be adjusted via grain boundary engineering.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）