STARCH-STARKE
·
2022
·
IF 2.688
Junhui Li,Yuanhao Deng,Hanyi Feng,Hao Yuan,Yizhou Fang,Yunyun Yang,Guangrong Hunag
The modification of starch by a single freeze-thawing process and acid hydrolysis has been reported, while the combination of freeze-thawing and acid hydrolysis on the microstructure and physicochemical properties is unknown. The present study investigates the supporting effect of freeze-thawing pretreatment by comparing single modifications with the corresponding freeze-thawing assisted acid hydrolyzed starch in terms of granular, physicochemical, and thermal properties. Starch samples treated by combined treatment show the most severe damage on the surface and the oil adsorptive capacity is enhanced from 69.7% to 109.4%. In addition, the solubility of starch granules is notably improved by 35.9% and the swelling power decreases by 39.7% via the combined treatment, respectively. The results of Fourier transform infrared spectroscopy and X-ray diffraction indicate that in comparison with native corn starch, the chemical groups of modified starch processed by combined treatment are not altered, while the relative crystallinity significantly increases from 31.4% to 33.9%. Significant changes in the thermal effects are attributed to molecular rearrangements after hydrolysis of amylose in the amorphous regions. Therefore, the combined treatment would be an efficient and useful method to prepare functional starch.
研究领域:
食品科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Hongxing Zhan,Hailu Wang,Huayun Sun,Yuanbing Li,Shujing Li,Zhen Cai
Mullite-corundum ceramics with various mullite crystal structures were prepared by incorporating Fe 2 O 3 into the ceramic powder. The impact of the Fe 2 O 3 content on the morphological evolution and formation mechanism of mullite crystals, as well as the thermal shock resistance and enhancement mechanism of the ceramic, were investigated. The results show that Fe 2 O 3 facilitates the formation of a low-viscosity liquid phase and enhances the dissolution-precipitation mass transfer rate at the liquid/solid interface, forming an iron-containing mullite solid solution, inducing lattice distortion, and accelerating the c-axis growth of mullite crystals. With increasing Fe 2 O 3 content, the mullite crystals changed from short columnar to elongated structures, and the grains were gradually interwoven with each other to form a network structure. The intergranular fracture mode of the sample was transformed into a mixed mode of transgranular and intergranular fractures. The maximum flexural strength was 83.60 MPa, with a retention rate of 94.65%, indicating improved strength and thermal shock stability.
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
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Zhuoqun Han,Jia Liu,Weiwei Wang,Qingxuan Zhou,Zhicheng Zhao,Yongning Han,Yingying Wang,Yang Wang,Futian Liu,Ling Li
Si 3 N 4 ceramics with high mechanical properties and thermal conductivity, exhibiting fine and bimodal microstructure, were prepared by adjusting the Er 2 O 3 /MgO ratio and hot-pressing sintering at 1800°C for 4 h. The microstructure, grain distribution, lattice oxygen content, mechanical properties, and crack propagation process of the sintered bulk samples were systematically investigated. It was found that a low Er 2 O 3 /MgO ratio contributed to the densification of Si 3 N 4 ceramics, whereas a high Er 2 O 3 /MgO ratio favored the grain growth of Si 3 N 4 ceramics. In this research, the grain size distribution and average diameters as well as their impact on mechanical properties were examined. When the ratio of Er 2 O 3 /MgO was 3:1, Si 3 N 4 had a larger average diameter and higher thermal conductivity, but the mechanical properties were somewhat reduced. When the ratio of Er 2 O 3 /MgO was 2:2, the sample displayed enhanced mechanical performance, which can be explained by the formation of a bimodal structure. The research indicates that it is feasible to control the microstructure and optimize the mechanical properties of Si 3 N 4 ceramics by tailoring the sintering additives.
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
Processes
·
2024
·Vol. 12
·期 1
·102
·
IF 2.8
Tingting Lv,Fang Tian,Tu Hu
Titanium carbide has attracted widespread attention due to its excellent properties. This study investigates the process of carbon thermally reducing TiO2to prepare TiC through a combination of thermodynamic analysis and experiments. The effects of temperature, TiO2/C molar ratio, and time on the phase transformation and morphology evolution of the products are investigated. The synthesis of titanium carbide involves the main reduction path of TiO2–Magnéli–Ti3O5–Ti2O3–TiCxO1−x. With the increase in reaction temperature and TiC content, the microstructure transitions from a smooth disc-like structure to a loose and porous layered structure, while the particle size decreases significantly. The carburisation rate of the reduced product is more affected by temperature, according to chemical analysis. The carburisation rate increased from 18.37% to 36.09% for 2 h–10 h of holding time at 1400 °C, and from 51.43% to 77.57% for 2 h–10 h of holding time at 1500 °C. The quantification of the carburisation rate provides a valuable reference for the preparation of titanium carbide by TiO2.
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
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2024
·
IF 2.5
Yingming Zhang,Yujie Yang
Nowadays, the rapid development and demand of electronic products have prompted electronic components to develop towards miniaturisation and even thin film, high integration and modularisation, high performance and ultra-high frequency applications. With the rapid development of electronic information technology and electronic field, NiZn ferrite material as a representative material in the soft magnetic material, through the optimisation of process technology to develop soft magnetic ferrite material with excellent performance is of great practical significance. In this study, Ni 0.3 Zn 0.5 Mg 0.2 Gd x Fe 1.96- x O 4 ( x = 0, 0.02, 0.04, 0.06, 0.08) ferrite materials were prepared by an economical solid phase method. The XRD patterns show that NiZnMgGd ferrite materials can be successfully prepared at low doping content of Gd. However, when x ≥ 0.06, the excess Gd 3+ reacts with Fe 3+ and O 2− in the raw material to produce the heterogeneous phase GdFeO 3 . From the SEM images, it can be seen that the higher the Gd content, the higher the number of small grains in the sample. A small amount of Gd 3+ doping has a contributing effect on reducing the P cv of ferrite. The quality factor of the ferrite sample with x = 0.02 is 11.92 when the frequency is 1000 kHz, which is an improvement of 100.67 % compared to the ferrite without Gd doping. From the M−H curves, M s decreases with the increasing content of Gd replacing Fe, and NiZnMgGd ferrite is more likely to reach saturation under the action of external magnetic field. M s , M r and H c indicate that NiZnMgGd ferrite material has typical soft magnetic properties.
研究领域:
材料科学
·
电子材料
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
Food Chemistry-X
·
2024
·
IF 6.5
Yingying Yu,Wuyin Weng,Zhongyang Ren,Yucang Zhang,Ping Li,Linfan Shi
This study aimed to simulate cold chain sales temperatures to predict the effects of temperature fluctuations on the physicochemical properties, moisture distribution, microstructure, and flavor of mashed potatoes. The results showed a decline in the hardness and chewability of mashed potatoes alongside the migration of water from bound water states to weakly bound states under freeze-thaw cycles (FTC) conditions. Microstructural analysis indicated that the adhesive forces between proteins and starch granules were weakened, and the structure of mashed potatoes particles was destroyed following FTC. The oxidation and degradation of fat induced by FTC increased the content of key compounds such as octanal and nonanal, thereby contributing to an overall deterioration in the flavor of mashed potatoes. This study elucidates the effects of FTC on water migration, microstructure, and flavor characteristics of mashed potatoes, thereby providing a theoretical foundation for improving the quality of prefabricated frozen mashed potatoes dishes.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Transactions of the Indian Ceramic Society
·
2022
·
IF 2.355
Qiang Liu,Juan Wang,Wensheng Liu,Lingjiao Zhan,Shaoheng Peng,Shuwei Yao,Yunzhu Ma
In order to optimize the phase composition and grain size of alumina fibers, 0-3 wt% SiO2 were induced to prepare alumina fibers using sol-gel method with the reaction of aluminium powder, formic acid, acetic acid, nitric acid and SiO2 sol. Effects of low SiO2 content on the phase transition and microstructure of alumina fibers were investigated. X-ray diffraction analysis and differential scanning calorimetry results showed that the addition of silica delayed the formation of α-Al2O3, and the phase transformation path of alumina was changed from amorphous alumina → γ-Al2O3 → α-Al2O3 to amorphous alumina → γ-Al2O3 → θ-Al2O3 → α-Al2O3. Moreover, scanning electron microscopy and transmission electron microscopy results confirmed that the addition of SiO2 reduced the grain size and was beneficial for the dense structure. Fine-grained dense alumina fibers composed of α-Al2O3 phase and transitional alumina phase were obtained by adding 1 wt% and 3 wt% silica after sintering at 1200°C for 1 h.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Yong Lu,Huixia Feng
Phytic acid (PA) has a potential use as a coating on metal surface to retard corrosion. However, a loose structure and micro-cracks in the phytic acid coating layer damage the tightness of the coating, providing channels for the infiltration of corrosive media and seriously weakening the protective effect of the coating. Sodium alginate (SA) was added as an accelerating agent to improve the anti-corrosion protective effect and coating densification of the phytic acid coating on a Q235 steel surface. The micro-morphology, elemental composition and elemental chemical state of different samples were observed by the surface analysis technologies of scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrum (EDS) and X-ray photoelectron spectroscopy (XPS), all of which show a dense and homogenous phytic acid film with lower crack was precipitated on the sample treated by PA-SA conversion coating. Atomic force microscopy (AFM) and contact angle measurements were used to evaluate the adhesion properties of the prepared coating and the results showed that the PA-SA coated steel exhibited better wettability and adhesion to the top layers compared to the bare steel and phytic acid coating. The electrochemical measurements show that the corrosion resistance of the conversion coating was markedly improved on the steel substrate treated by phytic acid conversion bath containing SA.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 3
·036522
·
IF 1.929
Bohua Duan,Tao Zhou,Guo Yang,Donglin Yang,Dezhi Wang
Tungsten-nickel-manganese alloy is an excellent potential replacement of depleted uranium alloy for kinetic energy penetrator (KEP) due to its high self-sharpening effect. In this work, the 90W-4Ni-6Mn alloy was prepared by vacuum sintering, and the effects of the sintering temperature and oxygen content on its microstructure and properties were discussed. Sintering temperature had a great influence on the properties of tungsten heavy alloy. The optimal properties of 90W-4Ni-6Mn with the relative density of 99.43%, the W grain size of 3.80 μm, and the compressive strength of 2790 MPa were obtained at the sintering temperature of 1125 °C for 60 min under a vacuum of 10−2∼10−3 Pa. With the increase of oxygen content, the densification of powders became more difficult, and the microstructure homogeneity and mechanical properties of sintered samples decreased accordingly. The results provide a new effective way to prepare W–Ni–Mn alloy with high performance.
研究领域:
材料科学
·
金属学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Jiawei Wei,Bingqiang Han,Xuancheng Wang,Junfeng Chen,Yaowu Wei,Wen Yan,Nan Li
In this paper, CaO granules were prepared, using the slaked lime as the raw material as well as ZrO 2 , TiO 2 , and V 2 O 5 as additives, respectively. The influence of different additives on the sintering properties, microstructure and hydration resistance of CaO granules was investigated. The results indicated that the introduction of additives could obviously promote the densification and the hydration resistance of the specimens. Especially, the sintering mechanisms of the specimens with different additives were studied. For the specimens with ZrO 2 and TiO 2 as additives, the in-situ formed CaZrO 3 and Ca 3 Ti 2 O 7 between grain boundaries promoted the densification to enhance the properties of the granules. However, the adding of V 2 O 5 generated a coating on the surfaces of CaO granules which contributed to the best hydration resistance.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED PHYSICS
·
2019
·Vol. 125
·期 16
·
IF 2.328
Wang Zhiwei,Kou Zili,Zhang Yuanfen,Yang Ming,Gong Hongxia,Liang Hao,Huo Ruizhi,Guan Shixue,Yin Xiaoshuang,He Duanwei
The influence of sintering pressure on the mechanical properties of bulk titanium carbide (TiC) fabricated through work hardening at high pressure and high temperature is investigated systematically. A series of pure polycrystalline TiC samples are prepared by sintering micrometer-sized TiC powders at a pressure of 9.0–14.0 GPa and a temperature of 1500 °C. These samples are then characterized by various techniques for determining their residual stress, grain size, density, microstructural defects, hardness, and fracture toughness. The results demonstrate that the Vickers hardness H V and the fracture toughness K IC depend strongly on the sintering pressure. It is found that the mechanical properties of the sintered samples improve with increasing sintering pressure. The relative density increases with increasing sintering pressure, reaching near full density at 14.0 GPa. The hardness and fracture toughness of the sample sintered at 1500 °C at 14.0 GPa pressure are 31.2 GPa and 4.2 MPa m 1/2 , respectively. The high-pressure and high-temperature environment causes severe plastic deformation of the grains, as well as a high density of dislocations, resulting in a dislocation pileup. The latter, together with the production of defects such as sub-boundaries and stacking faults, provides strengthening and stabilizing effects and improves the material hardness.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Xiao Feng,Tingting Chen,Yuqiao Yin,Yingjie Xu
By a comparative study of the concentration-dependent IR spectra of methyl benzoate (MB)/methanol- d 4 and MB/ n -hexane mixtures, it is found that the infrared wavenumber ( υ ˜ ) of ester group (O C O) of MB in the former system decreased exponentially with the increase of mole fraction of MB ( x 1 ), while that of the latter system decreased linearly, suggesting that H-bonding interaction plays an important role in the microstructure of MB/methanol- d 4 mixture. Therefore, to explore the microstructure and characterize the strength of H-bonding interaction of MB/methanol mixture, the excess infrared wavenumber of a group ( υ ˜ group E ) is proposed, showing that υ ˜ O − D E of methanol- d 4 presents an S shape with a minimum value at x 1 ≈ 0.4 and a maximum value at x 1 ≈ 0.8, respectively. Furthermore, the absolute value of υ ˜ O − D E (| υ ˜ O − D E |) of the former is greater than that of the latter, suggesting that H-bonding interaction in methanol- d 4 molecules is stronger than that between methanol- d 4 and MB. While both υ ˜ C = O E and υ ˜ C − O E of MB show a negative deviation with minimum values at x 1 ≈ 0.4, and | υ ˜ C = O E | is larger than | υ ˜ C − O E |, indicating that C O is directly involved in H-bonding interaction with O D, resulting in the change of υ ˜ C − O E through the electronic conjugation effect. To confirm the microstructure obtained from IR spectra, densities, speeds of sound , and viscosities of MB/methanol mixture are measured and excess properties are calculated. The results show that both excess molar volumes and isentropic compressibility deviations have a negative deviation with a minimum value at x 1 ≈ 0.4, which is good consistent with x 1 corresponding to the minimum value of υ ˜ O − D E , υ ˜ C = O E , and υ ˜ C − O E , respectively. Moreover, viscosity deviations exhibit a negative deviation with a minimum value at x 1 ≈ 0.8, which is good consistent with x 1 corresponding to the maximum value of υ ˜ O − D E .
研究领域:
物理化学
·
光谱学
✓ 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）