JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2024
·
IF 2.5
Chunwei Leng,G. Yang,Quanmin Xie,Yidi Li,Jun Yang,E. Ranjith Kumar
In this work, a highly-dense cementite (Fe 3 C) was synthesized via ultra-high pressure method (UHPM). Different raw batches were prepared under identical synthetic conditions (1000 °C and 4.0 GPa for 10 min). Large amounts of Fe 3 C were produced from the raw material consisting of ∼ 6 µm iron powder with ∼ 1.5 µm graphite, illustrating that the particle size and carbon source are critical for synthesizing Fe 3 C via UHPM. The crystal size of the synthesized Fe 3 C was estimated to be approximately 19 nm by peak broadening of the X-ray diffraction pattern. Additionally, the synthesis of Fe 3 C was confirmed by electron probe microanalysis analyzer (EPMA) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) images showed clearly shaped grain boundaries. The excellent mechanical properties of the prepared Fe 3 C were confirmed based on an ultrasonic pulse reflecting method. According to the magnetic-hysteresis loop of the Fe 3 C, it displayed soft ferromagnetic properties.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2024
·
IF 24.4
Zhanxiang Yin,He Zhang,Yaqiang Wang,Yi Wu,Youbo Xing,Xue Wang,Xufei Fang,Yuan Yu,Xin Guo
Dislocations as line defects in crystalline solids play a crucial role in controlling the mechanical and functional properties of materials. Yet, for functional ceramic oxides, it is very difficult to introduce dense dislocations because of the strong chemical bonds. In this work, the introduction of high-density dislocations is demonstrated by ultrahigh-pressure sintering into a typical ceramic oxide, BiCuSeO, for thermoelectric applications. The ultrahigh-pressure induces shear stresses that surpass the critical strength for dislocation nucleation, followed by dislocation glide and profuse multiplication, leading to a high dislocation density of ≈9.1 × 10 16 m −2 in Bi 0.96 Pb 0.04 CuSeO ceramic. These dislocations greatly suppress the phonon transport to reduce the lattice thermal conductivity, reaching 0.13 Wm −1 K −1 at 767 K and resulting in a record-high zT of 1.69 in this oxide thermoelectric ceramic. This study demonstrates the feasibility of generating dense dislocations in ceramic oxides via ultrahigh-pressure sintering for tuning functional properties.
研究领域:
材料科学
·
物理学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Fangming Liu,Jiawei Zhang,Pingping Liu,Qihuang Deng,Duanwei He
High pressure obviously decreased the sintering temperature of high melting point ceramics and produced bulks with excellent mechanical and thermal properties. In this study, the effect of pressure alone on the densification process of alumina ceramics was demonstrated. The translucent alumina bulks with unexpected hardness were obtained by compressing α-Al 2 O 3 powder under ultra-high pressure at room temperature. Through analyzing microstructure and hardness of cold compressed samples, the results reveal that ultra-high pressure could crush alumina grains under appropriate pressure, and initiate plastic deformation of grains when the applied pressure exceeds the yield strength of alumina. Thus to enhance the hardness of the samples by grain boundary strengthening and plastic deformation at higher pressure.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Mingjing Zheng,Xin Tian,Zhipeng Li,Tao Hong,Yanbing Zhu,Yuanfan Yang,Qingbiao Li,Hui Ni,Zedong Jiang
Porphyra haitanensis polysaccharides (PHP) has potential antioxidant and hypolipidemic activities, but still needs improvement. Therefore, ultra-high pressure (UHP) assisted extraction was applied to modify the structure, antioxidant, and hypolipidemic activities of PHP. UHP assisted extraction increased the total sugar, uronic acid, and 3,6-anhydro-ʟ-galactose contents of PHP, which increased by 15.85%–16.12%, 18.95%–24.32%, 20.54%–23.66% with 500–600 MPa UHP, respectively. Meanwhile, UHP modified PHP became more rough and porous than native PHP. Besides, UHP assisted extracted PHP showed better in vitro antioxidant and hypolipidemic abilities. Especially, 500–600 MPa UHP increased 72.43%–86.42% 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacities, 12.32%–12.82% pancreatic lipase inhibitory ability, and 14.93%–15.23% glycocholate binding abilities of PHP ( p < 0.05). Moreover, UHP assisted extracted PHP greatly decreased the lipid droplet and triglyceride contents of 3T3-L1 adipocytes ( p < 0.05). Our findings can provide the theoretical basis for the high value utilization of Porphyra haitanensis and its polysaccharides with UHP modification.
研究领域:
食品科学
·
药理学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
3 Biotech
·
2018
·Vol. 8
·期 4
·1-9
·
IF 1.497
Gao Jing,Zheng Caiju,Tan Tingru,Liu Shucheng,Ji Hongwu
Energy efficiency ratio is significant in completely estimating lignocellulosic biomass pretreatment. In this work, rice straw (RS) was pretreated by ultra-high pressure (UHP), ionic liquid microemulsion (ILM), and a combination of UHP and ILM (ILM + UHP) at mild temperature. The chemical composition, crystalline structure, surface morphology, and enzymatic hydrolysis of untreated and pretreated RS samples were compared. After ILM pretreatment ([Emim]Ac/cyclohexane/Triton X-100/ n -butanol = 0.25/0.15/0.45/0.15) at 500 MPa, 50 °C for 4 h, the cellulose content of the regenerated RS increased by 62.5, 66.2% of the lignin was removed, 37.3% of crystallinity index decreased, and the reducing sugar yield of 89.6% was achieved. All results show that the ILM + UHP pretreatments were more effective than sole UHP or ILM treatment at low temperature.
研究领域:
生物能源
·
植物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Jia Hongsheng,Li Jiaqi,Niu Rui,Ye Chaochao,Ru Hongqiang,Liu Baochang,E. Yuanlong,Li Haibo
In this work, the Silicon nitride composite ceramics (β-Si 3 N 4 ) by ultra-high pressure sintering were investigated. And the effect of sintering temperature , hold time and α-Si 3 N 4 powders on the sintering process had been analyzed in detail. These experimental results showed the larger particle size and lower porosity had an obvious effect on the thermal conductivity . Meanwhile, the addition of α-Si 3 N 4 powder could be also attributed to thermal conductivity. We had been calculated the porosity of β-Si 3 N 4 composite ceramics that the sample D (0.26%) was lower than the others samples. For a comparison, the thermal conductivity of sample D was up to 64.6 W/m K that was also attributed to its higher diffusion rate and small grain size.
研究领域:
材料科学
·
热传导工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Yang-Chao Zhang,Xing Fan,Fei Wang,Chu-Fan Wang,Guo-Sheng Li,Yang-Yang Xu,Wen-Long Mo,Xian-Yong Wei,Feng-Yun Ma
Two coal samples with different coalification degrees were extracted by ultrasonic extraction (UE), thermal dissolution (TD) at 300 °C, and ultra-high pressure extraction (UHPE) at 300 MPa using three solvents, methanol, toluene and acetone. Orbitrap mass spectrometry (MS) was used to analyze coal extracts and molecular characteristics were further elucidated by in-source collision activated dissociation, a tandems MS method. UHPE exhibited an excellent extraction yield, which is related to the acquirement of compounds with long-chain structures. Unlike UE and TD, more compounds containing 3 to 4 oxygen atoms per molecule were extracted by UHPE method. Oxygen distribution index indicates most oxygen atoms in UHPE extract exist on the side chains of aromatic structures. Therefore, advanced separation method reveals that multiple oxygen-containing functional groups (3 and 4 oxygen atoms) on side chains should be the major structure of organic oxygenates in low-rank coals, which is a new knowledge of coal chemistry.
研究领域:
煤化学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2021
·Vol. 329
·期 3
·1407-1415
·
IF 1.371
Wang Yinghui,Zhao Meng,Zhang Lili,Chen Yuantao
The radioactive iodine in nuclear waste is increasingly polluting the environment, and the careful handling of radioactive iodine is crucial to the sustainable development of nuclear energy. In this paper, a imine-based Covalent organic polymer (COP) is prepared by aldimine condensation. The COP material is stable under 500 MPa ultra-high pressure with an average particle size of 100 μm. The adsorption process is in line with the Langmuir isotherm adsorption model control, and the maximum adsorption capacity is 3082.14 mg/g. The adsorption is a spontaneous endothermic process of increased entropy and raising the temperature is conducive to the adsorption process. The electron donor and iodine electron acceptor in the ligand form an electron transfer compound to achieve iodine adsorption.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Open Ceramics
·
2024
·
IF 2.9
Mengting Lin,Zhangtian Wu,Ji Zou,Weimin Wang,Wei Ji,Zhengyi Fu
In this work, nanocrystalline high-entropy ceramics (HECs) were prepared by the combination of combustion synthesis and ultra-high pressure sintering. The prepared high-entropy (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 ) 2 Zr 2 O 7 ceramic powder had the average grain size of 11 nm and displayed the disordered defective fluorite structure. The HECs sintered under ultra-high pressure showed the defective fluorite structure, whereas the control samples fabricated by pressureless sintering showed the ordered pyrochlore structure. The HECs sintered under pressure of 10 GPa possessed much smaller grain size than that obtained by pressureless sintering. In particular, the grain size of ceramics sintered under 10 GPa at 600 °C was not significantly larger than that of raw powder and its Vickers hardness was 11.9 GPa. Ultra-high pressure sintering could remarkably increase the density of ceramics and restrain the growth of grains. The plastic deformation under ultra-high pressure was believed as the main densification mechanism for the grain refinement and performance improvement.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2021
·
IF 4.556
Tang Liqin,Liu Haocheng,Wen Jing,Xu Yujuan,Tian Wenni,Li Lu,Yu Yuanshan,Lin Xian,Fu Manqin
The acquisition of yellow extract (YE) from gardenia ( Gardenia jasminoides ) fruit can promote the application of natural pigment. This study aims to establish an effective method for extracting YE from gardenia fruit and to evaluate the properties of YE. First, the seven compounds in YE obtained by ultrahigh-pressure extraction (UPE) were identified by LC-TOF-MS/MS. The effects of traditional extraction (TE), ultrasonic extraction (UE), and UPE methods on the yield of YE were then investigated. The results showed that the extraction yield of UPE was 7.73 ± 0.89 mg/g DW under the optimized conditions (47.78% ethanol concentration, 114.95 s time, and 18.08 mL/g liquid–solid ratio), which was higher than those of UE (4.81 ± 0.23 mg/g DW) and TE (3.55 ± 0.21 mg/g DW). Finally, the YE stability of UPE was studied. The results showed that the YE stability of UPE was similar to that of the TE group, and both of which were greatly affected by higher temperature (60–100 °C), ultraviolet radiation, alkalinity , and Fe 3+ . Meanwhile, YE of UPE had better stability under ultraviolet radiation and alkalinity in comparison with the TE group. Therefore, UPE is a potential method for YE extraction from gardenia fruit.
研究领域:
食品科学
·
植物化学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2024
·
IF 9
Ya-Peng Du,Xin-Yu Tian,Xiao-Ping Zheng,Yu Chai,Yu-Cang Zhang,Yan-Zhen Zheng
In this study, an innovative method for the high-efficiency production of 5-hydroxymethylfurfural (5-HMF) from cellulose were developed, overcoming the inherent recalcitrant physicochemical properties of cellulose. The method initiated with the ultra-high-pressure homogenization (UHPH) of a cellulose and formic acid mixture. This pre-treatment could highly enhance the 5-HMF yield compared with the reported pretreatment method. Following this, a catalytic system comprising a metal-based ionic liquid , 1-butyl-3-methylimidazole chloroaluminate ([BMIM][AlCl 4 ]) and acetic acid, was utilized to transform the pre-treated cellulose into 5-HMF. Reaction parameters such as temperature, duration, DMSO concentration, cellulose substrate amount, and the balance of ILs and organic acids were optimized to obtain the highest yield of 5-HMF. Besides, a combination of experimental characterization methods with quantum chemical calculations, aiming to elucidate the pre-treatment mechanisms was conducted. The integration of formyl groups into the cellulose structure and the intense shear forces applied during UHPH were observed. These factors contributed to disrupting the cellulose's chemical stability, reducing particle size, and shifting cellulose's structure towards a blend of crystalline cellulose and amorphous forms with decreasing crystallinity. These changes collectively heightened the reactivity of cellulose for subsequent catalytic transformations, fostering more effective interactions between the catalyst and substrate and thereby elevating the efficiency of cellulose conversion to 5-HMF.
研究领域:
生物化学
·
可再生能源
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 16
·11084-11095
·
IF 3.442
Wang Bing,Wang Yuan,Zhou Yun,Qi Fugang,Ding Qiujie,Li Junyu,OuYang Xiaoping,Liu Lixin
To well preserve the fine structure of MWCNTs in the fabrication of ceramic matrix composites, an ultra-high-pressure sintering method is employed here. The effects of the MWCNTs on the microstructure and properties of the composites are investigated. The B 4 C-MWCNTs composites are prepared under the pressure of 4.5 GPa at a low sintering temperature of 1300 °C for 10 min. The results indicate that the densification method is beneficial to protect MWCNTs from destruction and create a good interfacial combination between the MWCNTs and the matrix. The indentation crack length of the B 4 C-MWCNTs composites decreases and the electrical conductivity increases continuously with the increase of MWCNTs additive amount, reaching the optimum values at 5 vol% MWCNTs addition. The microstructural observations indicate that the reinforcement mechanism of the composites is mainly the crack branching, crack deflection, bridging, and pullout of MWCNTs. This finding provides a promising approach for producing more robust ceramics with CNTs reinforcing.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）