DIAMOND AND RELATED MATERIALS
·
2023
·
IF 4.1
Lin Chai,Yequn Liu,Wenjun Yan,Na Teng,Hongyan Li,Yongqin Qi,Haoliang Huang,Xiaojing Cui,Xianglin Hou,Tiansheng Deng
It is of fundamental and industrial interest to develop a facile method to modify the graphene sheets with heteroatoms such as oxygen (O) and nitrogen (N). Herein, the O and N atoms were discovered to be grafted onto the edges of graphene sheets during the simple grinding process with solvent in air or N 2 atmosphere. By combining X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscope (HRTEM), energy dispersive X-ray spectrometer (EDS), electron spin resonance spectroscopy (ESR) and H 2 O 2 experiments, we show where the O and N atoms were grafted and how the modification of graphene with O and N atoms occurred. The results showed that the O atoms of air and N atoms of solvent molecules could be bonded to the edges of graphene sheets during the grinding process, which followed the radical reaction mechanism.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2022
·
IF 8.047
Yuxin Chen,Shuairen Qian,Kai Feng,Zhengwen Li,Binhang Yan,Yi Cheng
The original phase-pure M1 MoVNbTeO x catalyst was mechanically treated with stirring water for several days under ambient conditions to obtain particles with different sizes. The catalytic performance was significantly improved and stabilized after about 7 days of treatment. Among all the catalysts, the sample treated in water for 7 days can obtain 57.6 % ethane conversion and 0.79 kg C2H4 /kg cat /h ethylene productivity while the original phase-pure M1 catalyst was only 19.2 % and 0.27 kg C2H4 /kg cat /h at reaction temperature of 400 °C and contact time of 18.5 g cat ·h/mol C2H6 . Meanwhile, the catalyst was systematically characterized and the results showed that there was essentially no difference in microstructure between the original and treated catalysts. TEM and SEM morphological characterizations presented that the particle size and aspect ratio of the catalysts changed significantly, in which the particle size of the catalyst become smaller and the proportion of basal surface was enhanced. The activity and selectivity of the catalysts exhibited a correlation with the amount and proportion of basal surface. It can be deducted that the basal surface is the most active and selective surface during oxidative dehydrogenation of ethane (ODHE) process, and the intrinsic activity based on the basal (0 0 1) plane of the catalyst remains stable after the mechanical treatment. Samples treated in water for 7 days showed excellent long-term stability in a 200 h stability test at reaction temperature of 440 °C and contact time of 9.3 g cat ·h/mol C2H6 . The present work demonstrated that the differences in the catalytic properties of different M1 samples depend mainly on the amount and proportion of exposed basal surface, and the possibility of enhancing the activity of orthorhombic M1 phase by fragmentation method.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
·
2020
·Vol. 58
·期 3
·1061-1071
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IF 1.946
Zhang Bin,Zheng Zhenjia,Liu Nan,Liu Pengli,Qiu Zhichang,Qiao Xuguang
The aim of this study was to investigate the effects of the sequence of different thermal and mechanical treatments on the physicochemical parameters and microstructure of garlic paste, in order to improve the quality of the product. The total organosulfur compounds (OSCs) decreased steadily in blended-heated garlic, whereas OSCs decreased sharply after 2 min at 75 °C or 5 min at 85 and 95 °C in heated-blended garlic. After blanching for 5 min, allicin could maintain over 4.0 mg/g only at 75 °C; and OSCs of heated-blended garlic paste were found to drop by 29.56%, 90.63% and 94.79% at 75, 85 and 95 °C, respectively. In blended-heated garlic, the color values of L * (lightness) and a * (redness) decreased ( P < 0.05), while the b * (yellowness) and C * (chroma) increased ( P < 0.05), obtaining green discoloration garlic paste. The total color differences of blended-heated samples were greater than 12.08, which were 2–6 folds higher compared with heated-blended garlic. Total phenolic content and antioxidant activity decreased ( P < 0.05) in all thermal treatments, thermal treatment of heated-blended garlic less than 5 min maintained over 30% of antiradical activity. The sequence of unit operations determined the pattern of garlic microstructure disruption, resulting in various enzymic and non-enzymic reactions. Our results indicated that use of heat treatment prior to blend processing is an effective and feasible method to inhibit garlic discoloration and retain high content of bioactive OSCs. It is recommended that garlic paste be prepared using heated-blended processing, with thermal processing limited to 75 °C for less than 5 min.
研究领域:
食品科学
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植物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Afroza Akter Liza,Shihao Wang,Yanchen Zhu,Hao Wu,Lukuan Guo,Yungeng Qi,Fengshan Zhang,Junlong Song,Hao Ren,Jiaqi Guo
This study aimed to explore the synergistic mechanism of lignin chromophore modifications via UV treatment and to analyze the effects of mechanical treatments on LCNF properties for future uses. The procedure involved two steps: first, lignin's chromophore modification via UV illumination, and then the ball milling process was proceeded for 1 h, followed by high-intensity ultrasonic for 15–135 min. Characterization included preserved lignin content percentage, FTIR, UV–vis NMR, and color analysis for UV-modified samples, and to access the influence of mechanical treatment on LCNF samples further yield, zeta potential analysis, XRD, thermogravimetric analysis, atomic force microscopy, and scanning electron microscopy were performed. LCNFs S-120 demonstrated a zeta potential of −21.7 mV, indicating enhanced stability compared to the S-135 sample (−10.95 mV). The S-120 sample also showed the highest yield (74.02 %) and TGA at 391 °C. In XRD analysis, the S-120 sample demonstrated the highest CrI 64.3 %, than the S-15 sample (48.2 %). Preserved lignin in the LCNFs led to a slight reduction in crystallinity across all samples but improved thermal stability for all the prepared LCNFs samples. The UV and ultrasonication improved the homogeneity and durability of the LCNF samples, enabling a process that may be used to industries.
研究领域:
材料科学
·
林业工程
✓ 已验证
DOI
PubMed
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2017
·
IF 2.589
K.Q. Song,Z.C. Lu,M. Zhu,R.Z. Hu,M.Q. Zeng
Nanocomposite Al–Sn-based bearing alloys produced by mechanical alloying (MA) exhibit high hardness; however, their poor sintering density and ductility limit their wide spread application. Here, we present a strategy to produce a dual-scale structure in an Al–Sn–Si alloy consisting of coarse and ultrafine grains through a combination of conventional powder sintering and thermomechanical treatment . We found that severe deformation and the presence of an Al–Si eutectic mixture for sample induced abnormal grain growth of Al to create the dual-scale Al–Sn–Si alloy through annealing treatment. An optimum matching of ductility and strength , and optimum wear performance were achieved at annealing temperatures of 500 and 550 °C. Detailed investigation of the wear mechanism revealed that the combination of high strength and high ductility provided by the dual-scale structure is a key factor for the improvement of the wear properties.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）