Defence Technology
·
2021
·Vol. 18
·期 10
·1852-1862
·
IF 3.172
Fa-yang Guan,Hui Ren,Wan-jun Zhao,Xin-zhou Wu,Qing-jie Jiao
To improve the thermal properties of aluminum (Al) in the energetic system, a coated structure with ammonium perchlorate (AP) was prepared by a facile approach. And N, N-Dimethylformamide (DMF) was chosen as an ideal solvent based on heterogeneous nucleation theory and molecular dynamics simulation. This coated structure could enlarge the contact area and improve the reaction environment to enhance the thermal properties. The addition of AP could accelerate oxidation temperature of Al with around 17.5 °C. And the heat release of 85@15 composition rises to 26.13 kJ/g and the reaction degree is 97.6% with higher peak pressure (254.6 kPa) and rise rate (1.397 MPa/s). An ideal ratio with 15 wt% AP was probed primarily. The high energy laser-induced shockwave experiment was utilized to simulate the reaction behavior in hot field. And the larger activated mixture of coated powder could release more energy to promote the growth of shockwave with higher speed up to 518.7 ± 55.9 m/s. In conclusion, 85@15 composition is expected to be applied in energetic system as a novel metal fuel.
研究领域:
材料科学
·
能源化学
·
热力学
·
纳米材料
·
燃烧学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 18
·e55316
·
IF 2.7
Jifa Bian,Zhongbin Ye,Xuecheng Zheng,Chengwen Deng,Lei Tang
This work used aqueous solution free radical polymerization to create polymers of 2-acrylamide-2-methylpropane sulfonic acid, itaconic acid, and allyl polyoxyethylene ether as a high-temperature resistant retarder (APMS/IA/APEG, from now on referred to as AIA). Gel permeation chromatography, fourier transform infrared (FTIR), proton nuclear magnetic resonance ( 1 HNMR), and thermo-gravimetric analysis (TG) were used to characterize their molecular structure and characteristics. Tests were conducted on the thickening time, rheological characteristics, and compressive strength of AIA in cement slurries. The cement slurry thickened for 276 min at 180°C during the test, and the cement stone's 24-h compressive strength was consistently more than 20 MPa. The hydration products were analyzed using x-ray diffractometer and scanning electron microscopy methods, which were then coupled with molecular dynamics simulations to elucidate the AIA retarding mechanism. When AIA is added to a cement slurry, it forms a chelate structure with Ca 2+ and a strong adsorption layer on the surfaces of the cement particles. This stops the cement from hydrating. The AIA side chain, APEG, can wrap the active group in AIA at low temperatures. AIA exposes more adsorption groups because of the APEG chains stretching at higher temperatures. AIA can, therefore, be used for deep well operations at high temperatures.
研究领域:
材料科学
·
石油工程
·
高分子化学
·
水泥化学
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Yanqi Gu,Shayu Li,Yuehong Xu,Jiaguang Han,Miao Gu,Zhipeng Cai,Yan lv,Guoxin Xie,Tianbao Ma,Jianbin Luo
The influence of an external magnetic field on the picosecond network dynamics of the salt (KCl) solution is investigated by terahertz time-domain spectroscopy. Because hydration changes the motions of water molecules clusters, we test hydration by measuring the change of dielectric loss caused by the slow relaxation of water molecules clusters. We find experimentally that the magnetic field enhances the number of water molecules involved in hydration and the radius of dynamic hydration layer in salt solutions. However, with the increasing concentration, there is a downward in the hydration enhancement per equivalent. Meanwhile, the simulated results show the number of water molecules in hydration layers increases which is consistent with our experimental results. Besides, the simulation reveals that external magnetic field mainly affects the second hydration layer and the stability of water molecules network in hydration layer is enhanced with external magnetic field .
研究领域:
物理化学
·
生物物理
·
分子生物学
·
光谱学
·
溶液化学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Hui Jiang,Xiaoyan Liu,Ying Xu,Yongying Jia
As a complex component of crude oil, asphaltenes determine the stability of emulsion . However, the mechanism of asphaltenes stabilize emulsion is still insufficient recognition due to the complexity of the molecular structure of asphaltenes. In this paper, the experiments and dissipative particle dynamics simulations were used to study the interfacial properties of asphaltenes. The adsorption of asphaltenes at the oil–water interface was studied by interfacial tension (IFT) experiments. A realistic molecular structure of asphaltene was constructed on the results of the characterization of the asphaltenes. The effects of asphaltenes concentration, temperature, and shear on the formation and stability of emulsion based on this molecular structure were investigated by simulations. The results show that the IFT decreases as asphaltenes concentration increases, while the droplet size of the emulsion decreases and becomes more uniformly distributed. Increasing the temperature enhances the interfacial activity of the asphaltenes, but also promotes its dissolution in the oil phase, which has a negative effect on reducing the IFT value and the stability of the emulsion. As the shear rate increases , the configuration of the emulsion changes from droplets to ellipsoids and rods, and the structure of the interfacial film is disrupted. This work provides useful insights into the mechanisms of asphaltenes concentration, temperature, and shear on the stability of the emulsion.
研究领域:
石油化学
·
胶体与界面科学
·
流体力学
·
分子模拟
·
能源工程
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Weiyi Zhang,Haozhen Zhang,Xinglian Xu,Xue Zhao
The oil polarity was hypothesized to significantly influence the microscopic conformation of interfacial myofibrillar protein (MP) and thus the mesoscopic interfacial rheology of MP film , which ultimately tuned the macroscopic stability of MP-stabilized emulsions. In this research, the inner mechanism was revealed hierarchically based on emulsions multi-scale properties, by a combination of in vitro interfacial concentration measurement, dynamic interfacial tension measurement and interfacial dilatational rheology (highlighting Lissajous plots). Then, the above conclusion was verified through in silico molecular dynamic simulation. At macroscopic level, the light scattering results showed that emulsion prepared with higher polarity oil exhibited higher physical stability. This could be explained from the mesoscopic perspective that: (1) the adsorption dynamics of MP was faster (though lower diffusion rate, but higher penetration and rearrangement rate) on the higher polarity interface, which decreased interfacial tension more efficiently; (2) adsorption ratio, surface load and desorption ratio indicated that ‘multilayer interfacial film’ was formed by loosely-bound MP on the lower polarity interface, which decreased the effective interfacial coverage to impair emulsions stability; (3) Lissajous plots showed that interfacial structure with higher stability against large deformation was formed on the higher polarity oil interface. Finally, the microscopic molecular mechanism for explaining the above findings was revealed by in silico molecular dynamic simulation: though MP was less unfolded on the higher polarity interface leading to weaker intermolecular hydrophobic interactions, this compact molecular structure with stronger intramolecular rigidity predominantly contributed to steadier interfacial film structure. This multi-scale study provides a deep insight into the inner relationship between oil polarity and emulsions stability.
研究领域:
食品科学
·
胶体与界面化学
·
蛋白质构象
·
软物质物理
·
分子模拟
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）