INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 7
·6379
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IF 5.6
Zhaoxuan Li,Jingling Liu,Jie You,Xin Li,Zongsuo Liang,Junli Du
To fully explore the influence mechanism of interactions between different monomer units of proanthocyanidins (PAs) on biological activity, a path analysis model of the PA structure-activity relationship was proposed. This model subdivides the total correlation between each monomer unit and activity into direct and indirect effects by taking into account not only each monomer unit but also the correlation with its related monomer units. In addition, this method can determine the action mode of each monomer unit affecting the activity by comparing the direct and total indirect effects. Finally, the advantage of this model is demonstrated through an influence mechanism analysis ofRhodiola crenulataPA monomer units on antioxidant and anti-diabetes activities.Keywords:proanthocyanidins;structure-activity relation;path analysis;Rhodiola crenulata
研究领域:
药理学
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化学生物学
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植物科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2016
·
IF 3.611
Jingshan Wang,Xibin Wang,Xiangshan Fan,Kangkang Yang,Yingjia Zhang
Kinetic analyses were performed based on the experimental results of ignition delay times of 2-methyltetrahydrofuran (2-MTHF) using shock tube technique at temperatures of 1050–1800 K, equivalence ratios of 0.5–2.0, fuel mole concentrations of 0.25–1.0%, and pressures of 1.2–10 atm. A new kinetic model of 2-MTHF oxidation named Mech III was established according to the analysis of simulation using two published models (Mech I from Ravi Fernandes group and Mech II from Battin-Leclerc group) and the experimental data in this work. Comparison between simulation and experimental data indicated that Mech II shows remarkable under-prediction while Mech I gives a good agreement with ignition delay times under most conditions except for underprediction on fuel-rich mixtures at relative low temperature around 1250 K. Sensitivity analysis indicated that both models underestimated ignition delay times for the reactions of C 0 -C 4 molecules, so Mech III was formed by introducing such reactions and can demonstrate improved simulation performance under all conditions. Reaction pathway analysis of Mech III showed that 2-MTHF is mainly consumed through fuel decomposition at high temperatures (around 1550 K), and H-atom abstraction reactions at lower temperatures (around 1250 K), respectively. The comparative experimental and kinetic study between 2-MTHF and 2-methylfuran (MF) indicated that 2-MTHF has higher ignition delay times under the same conditions in this work, while the disparity decreases as the temperature increases, and 2-MTHF produces less soot precursors under high temperature conditions.
研究领域:
化学动力学
·
燃烧科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Ruirong Ma,Xinhui Wang,Ning Zhang,Yang Cao,Qian Yao,Quan-De Wang,Jinhu Liang
The high-temperature pyrolysis characteristics of C 1 –C 5 linear alcohols, including methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol, systematically studied experimentally and the results interpreted using a detailed kinetic model. Specifically, a single-pulse shock tube coupled to a gas chromatography-mass spectrometry (GC-MS) system and a gas chromatograph (GC) is used to conduct a comprehensive experimental study on the high-temperature pyrolysis of the five alcohols, at pressures of 5 and 10 bar, in the temperature range 1000–1800 K at 1% fuel diluted by argon. Qualitative and quantitative analyses are conducted on the reactant, intermediate, and product species involved to determine species distributions as a function of temperature. A detailed chemical kinetic mechanism, NUIGMech1.3, is used to simulate the experimental data under the working conditions. The simulation results are compared with the experimental results, and it is shown that the overall trends between experiments and model predictions are relatively ideal in the comparison of all product and reactant concentrations, even though there is still a phenomenon of inaccurate prediction. Reaction pathway analysis is then conducted on the five alcohols. The present work not only provides additional experimental data for alcohols, but also provides insights into the high-temperature pyrolysis characteristics of the five fuels, which will be valuable for further development and optimization of detailed kinetic mechanisms of these alcohols and promote their practical application.
研究领域:
化学工程
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能源科学
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燃烧动力学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jizhen Zhu,Sixu Wang,Mohsin Raza,Yuan Feng,Jing Li,Yebing Mao,Liang Yu,Yong Qian,Xingcai Lu
Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process . It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO 2 while CH 3 OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.
研究领域:
燃烧化学
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燃料科学
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化学动力学
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内燃机工程
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替代燃料技术
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Xue Jiang,Tianqi Zhang,Zefeng Lin,Yingjia Zhang,Zuohua Huang,Wei Zhu,Linxun Xu,Suxian Xu
The effect of water addition on the ignition delay times of ethanol/ iso -octane mixtures was measured in a shock tube at pressures of 1.2 and 10 atm, temperatures from 943 to 1383 K, an equivalence ratio of 1.0, and water contents of 0 % to 40 % (mole fraction in total component). Results indicate that water addition non-monotonically affects ignition delay times at 1.2 atm, while at 10 atm, it has contrasting effects across different temperature ranges. Simulations from five representative literature models were compared with experimental data. Chemical kinetic analysis was conducted using both the Modified LLNL 2021 model and RWTH 2015 model at 10 atm and temperatures of 1300 K and 950 K. Reaction pathway analysis indicates that increased water content in the ambient enhances H-atom abstraction pathways by OH radicals during the ignition of both ethanol and iso -octane. Sensitivity analysis indicated that reactions involving hydrogen chemistry significantly influences ignition. Rate of production analysis identified consumption rates and pathways of H atom as key factors affecting temperature dependence after water addition. The fictitious diluent gas method was introduced to isolate thermal and chemical kinetics effects after water addition.
研究领域:
燃烧科学
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化学动力学
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燃料化学
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高压物理
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实验热力学
✓ 已验证
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Xiaojie Li,Erjiang Hu,Xin Lu,Shihan Huang,Zuohua Huang
Laminar flame speeds of hexene isomers (1-hexene, 2-hexene and 3-hexene) and n-hexane are investigated at equivalence ratios of 0.8–1.5, initial temperatures of 373–453 K and initial pressures of 0.1–0.5 MPa using a constant volume combustion chamber . Results show that laminar flame speeds of hexene isomers are similar to each other and higher than those of n-hexane. NUI model, Fan model and LLNL model are validated against the experimental data. Simulation results of NUI model and Fan model agree well with experimental data while results of LLNL model show large discrepancies. The discrepancies between hexene isomers and n-hexane are mainly caused by thermal effect. Reaction pathway analysis shows that hexene isomers undergo similar reactions including H-abstraction reactions, radical-addition reactions and unimolecular decomposition reactions . Sensitivity analysis also reveals that the sensitivity coefficients of fuel specific reactions of hexene isomers are close to each other on the whole.
研究领域:
燃烧科学
·
化学动力学
·
反应流动力学
✓ 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）