JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2016
·
IF 1.835
Dawei Li,Guangqian Li,Pingfeng Bian,Zhe Shen,Mengfan Fu,Wenjun Fang,Weidong Yan
Epigallocatechin gallate (EGCG) is the most abundant and active components in tea. In this text, the density and viscosity of ternary aqueous solution of EGCG containing LiCl/NaCl/KCl were determined at temperatures ranging from 288.15 to 308.15 K at atmospheric pressure. The density data was used to compute the apparent molar volumes (Vφ), limiting partial molar volumes (Vφ0), and transfer partial molar volumes (ΔtrsVφ0). The viscosity B-Coefficients were calculated from the measured viscosity data using the extended Jones–Dole equation. The values of density and viscosity increased continuously with the increasing of molality of EGCG and decreased with the temperature increasing. The positive values including (Vφ, Vφ0, ΔtrsVφ0, viscosity B-Coefficients, the free energies of activation for solvent Δμ10≠, and for solute Δμ20≠) and Helper’s constant (∂2Vφ0/∂T2)p close to zero indicated the presence of strong solute–solvent interactions and the structure–making effect of EGCG in the investigated solutions. The apparent molar isobaric expansions (Eφ0) decreasing with temperature suggested that the solute–solvent interactions became weaker as temperature increased. These significant parameters could provide necessary data about molecular interactions occurring in simulated body fluids.
研究领域:
化学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 43
·15688-15695
·
IF 4.39
Minghui Li,Jun Zhou,Ruoshan Lei,Huanping Wang,Feifei Huang,Shiqing Xu
Nowadays, there is enthusiastic effort to develop luminescent thermometers used for remote and high-sensitivity temperature readout over a wide sensing range. Herein, Pr3+ and Gd3+ co-doped ZrO2 nanocrystals are designed, prepared and investigated by XRD, Raman spectroscopy, XPS, TEM, EDS, DRS, PLE and PL spectroscopy. Upon 275 nm irradiation, the PL spectrum of ZrO2:Pr3+,Gd3+ is found to be composed of a narrow emission peak at 314 nm (Gd3+ 6P7/2–8S7/2), a broad defect-related emission band at 400 nm, and several emission peaks in the wavelength region of 585–700 nm (Pr3+ 1D2–3H4, 3P0–3H6, and 3P0–3F2), which exhibit different thermal responses owing to the effects of the various non-radiative relaxation processes and trap energy levels. Accordingly, the luminescence intensity ratio (LIR) between the Pr3+ 1D2–3H4 and Gd3+ 6P7/2–8S7/2 transitions demonstrates excellent relative sensing sensitivity values ((2.32 ± 0.01)% K−1–(8.32 ± 0.05)% K−1) and low temperature uncertainties (0.08 K–0.28 K) over a wide temperature sensing range of 303 K to 573 K, which are remarkably better than those of many other luminescence thermometers. What is discussed in the present study may be conducive to broadening the research region of RE3+ doped luminescence thermometric phosphors, especially for materials with rich 4f–4f transition lines and defect-related luminescence.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PURE AND APPLIED CHEMISTRY
·
2020
·Vol. 92
·期 10
·1673-1682
·
IF 1.919
Wanjing Cui,Hongfang Hou,Jiaojiao Chen,Yafei Guo,Lingzong Meng,Tianlong Deng
Densities of the sodium arsenate aqueous solution with the molality varied from (0.04165 to 0.37306) mol · kg −1 were determined experimentally at temperature intervals of 5 K from 283.15 K to 363.15 K and ambient pressure using a precise Anton Paar Digital vibrating-tube densimeter. The apparent molar volumes ( V
ϕ
), thermal expansion coefficient ( α ) and partial molar volume
(
V
¯
B
)
were obtained based on the results of density measurement. The 3D diagram of apparent molar volume against temperature and molality as well as the diagram of thermal expansion coefficient and partial molar volume against molality were plotted, respectively. On the basis of the Pitzer ion-interaction equation of apparent molar volume model, the Pitzer single-salt parameters (
(
β
M,X
(
0
)
v
,
β
M,X
(
1
)
v
,
β
M,X
(
2
)
v
and
C
M,X
v
,
M
X
=
N
a
3
A
s
O
4
)
and their temperature-dependent correlation F ( i , p , T ) = a
1 + a
2 ln( T /298.15) + a
3 ( T – 298.15) + a
4 /(620 – T ) + a
5 /( T – 227) (where T is temperature in Kelvin, a
i
is the correlation coefficient) for Na 3 AsO 4 were obtained on account of the least-squares method. Predictive apparent molar volumes agree well with the experimental values, and those results indicate that the single-salt parameters and their relational coefficients of temperature-dependence for Na 3 AsO 4 obtained are reliable.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Kui Wu,Yajun Li
The synthesis and separation processes of chemical intermediate is based on the knowledge of its solid-liquid phase equilibrium with solvents in industry. In this work, the solubility of 2-chlorobenzenesulfonamide in 16 single pure solvents including methanol, ethanol, n -propanol, isopropanol, n -butanol, isobutanol , acetone, 2-butanone, 2-pentanone, cyclohexanone , cyclopentanone , ethyl acetate , methyl acetate , ethyl formate , acetonitrile and tetrahydrofuran was determined at temperature range from 273.15 to 324.65 K and atmospheric pressure. The mole fraction solubility of 2-chlorobenzenesulfonamide in all selected mono solvents was enhanced by an increase in temperature. In addition, the experimental data were further correlated by the modified Apelblat equation, λh equation, NRTL model and Wilson model. The values of RAD with NRTL equation were smaller than those with other three models, and thus the NRTL model offered the best fitting performance. The thermodynamic functions of dissolution including enthalpy, entropy, and Gibbs energy were derived, and the results expectedly suggested a spontaneous and entropy-driven mixing process. All the crystallographic and thermodynamic data reported in this study provides the fundamental data for designing and optimizing of the reaction and crystallization processes of 2-chlorobenzenesulfonamide.
研究领域:
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2022
·
IF 3.269
Di Fan,Zidan Cao,Yu Li,Tao Li,Baozeng Ren
The mole fraction solubility data of flavoxate hydrochloride in twelve experimentally selected solvents were measured at atmospheric pressure by the laser monitoring method. The experimental temperature range was 278.15 to 328.15 K. The solubility of flavoxate hydrochloride showed a nonlinear increase with temperature increase. At a fixed experimental temperature, the order of solubility is: ethylene glycol > methanol > 2-methoxyethanol ≈ dimethyl sulfoxide > N -Methyl-2-pyrrolidone > water > 2-propoxyethanol > 2-ethoxyethanol > ethanol > n -butanol > n -propanol > acetonitrile. Also, solubility data were correlated by two semi-empirical models and three activity coefficient models. From the average relative deviation and root mean square deviation data of the five models, it can be seen that the Modified Apelblat model has the best correlation. Furthermore, in this work, the effect of solvent on the solubility of flavoxate hydrochloride was analyzed using the KAT-LSER model. Furthermore, the thermodynamic parameters (Δ dis G 0 , Δ dis H 0 , Δ dis S 0 ) of the dissolution process of flavoxate hydrochloride were calculated by the Van’t Hoff model. The data indicate that the dissolution process of flavonoid hydrochloride in twelve experimentally selected solvents is endothermic and entropy-driven.
研究领域:
药物化学
·
物理化学
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产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2025
·
IF 4.6
Linlin Wu,Qilin Xu,Cheng Su,Xianggang Yin,Xinyi Huo,Xiaohan Zhao,Yifeng Zhou,Jun Huang
Anji white tea, a premium green tea renowned for its distinctive characteristics and considerable economic value, traditionally relies on sensory evaluation and chemical analysis for quality assessment. Sensory methods, though intuitive, are subjective and time consuming, while chemical techniques such as gas chromatography and high performance liquid chromatography, provide only a limited view of a few chemical components. This study introduces hyperspectral imaging (HSI) technology to evaluate Anji white tea quality by simultaneously capturing spectral and image data. Spectral data were preprocessed and analyzed to extract features related to catechins, tea polyphenols, and free amino acids. Image data texture features were extracted using the gray-level co-occurrence matrix, and significant features related to tea grades were identified through correlation analysis. Classification models using support vector machine and K-nearest neighbors (KNN) algorithms were developed. To enhance model accuracy, two data fusion strategies—low-level and mid-level—were applied. The results showed that both fusion strategies outperformed single-data models, with the KNN model using mid-level fusion achieving 100 % accuracy in both the training and test sets. This study demonstrates the potential of HSI and data fusion in improving the accuracy of tea quality assessment, providing a solid framework for the scientific evaluation of Anji white tea.
研究领域:
食品科学
·
农业工程
·
计算机科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Lijiang Guo,Haijun Han,Ouyang Dong,Yan Yao
Water activities of the high concentration solid solution-aqueous solution system (SS-AS) KCl–RbCl–H 2 O and its sub-binary systems at T = 298.15 K and T = 323.15 K have been elaborately measured by an isopiestic method. The solubility of this ternary system at T = (298.15, 308.15 and 323.15) K was also measured by a Flow-Cloud-Point method. A Pitzer model was used to estimate the reliability of the solubility reported in the literature, and to judge the type of solid phase, by correlating the measured water activity and the reported solubility values. The binary model parameters as a function of temperature between T = 298.15 K and T = 323.15 K were obtained by fitting the water activities in the binary systems. The predicted water activities at T = 298.15 K and T = 323.15 K with the obtained binary parameters only, are in good agreement with the experimental values, which indicate that the Pitzer model can reliably represent the properties of the ternary system, with binary parameters only within the temperature range from T = 298.15 K to T = 323.15 K. Under the different assumptions that the equilibrium solid phase involved the pure salts (KCl (s) and RbCl (s) ) for the ideal solid solution or regular solid solution (K, Rb)Cl (ss) , the solubility isotherms at T = (298.15, 308.15 and 323.15) K were calculated and compared to experimental results, respectively. It was found that only the calculated solubility isotherms for (K, Rb)Cl (ss) regular solid solution are consistent with the corresponding experimental values. The solid phase equilibrated with the aqueous solution in the KCl–RbCl–H 2 O ternary system should be a regular solid solution (K, Rb)Cl (ss) . This conclusion also can be verified from the Lippman log ∑ K − X s − X act and Φ ∑ m − X s − X aq equilibrium diagrams.
研究领域:
物理化学
·
热力学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Rongrong Li,Jiaqi Weng,Cuihong Ye,Anguo Ying,Qizhong Zhou,Aiguo Zhong,Hao Chen,Jianguo Yang
The equilibrium solubility of sodium 2,4-diaminobenzene sulfonate in liquid mixtures (methanol + water, isopropanol + water, and 1,2-propanediol + water) were determined at temperatures ranging from (273.15 to 323.15) K. The solubility of sodium 2,4-diaminobenzene sulfonate increased with temperature increment but decreased with the concentrations of methanol, isopropanol or 1,2-propanediol in liquid mixtures. The obtained solubility data were correlated by Apelblat equation and Sun model. On the base of the measured solubility, the dissolution enthalpy ( Δ H sol o ) of the dissolution process were calculated.
研究领域:
药物化学
·
物理化学
·
药剂学
·
溶解行为研究
·
热力学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2017
·
IF 3.648
Junwei Zhang,Shuai Yang,Hang Li,Pengpeng Yu,Li Xu,Guoji Liu
The solubility of 1,6-Hexanediol in (methanol + dimethyl adipate (DMA)), ( n -butanol + DMA) binary solvents was measured by the dynamic method under 0.1 MPa. The studies were carried out at different mass fractions of methanol or n -butanol from 283.15 K to 303.15 K. The solubility of 1,6-Hexanediol in binary solvents increases with increasing temperature and mass fraction of methanol or n -butanol. In a fixed temperature and fixed mass fraction of methanol or n -butanol, the solubility of 1,6-Hexanediol in (methanol + DMA) is greater than in ( n -butanol + DMA). In addition, the experimental solubility data were correlated by Jouyban–Acree model, Van't Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model and Sun model, in which the Sun model shows the best agreement with the experimental solubility data. The maximum of relative average deviation ( RAD ) and the root-mean-square deviation ( RMSD ) between the experimental and calculated solubility were 5.85 × 10 − 2 and 3.80 × 10 − 2 , respectively. Additionally, the thermodynamic properties (including enthalpy, Gibbs energy and entropy) were also obtained, and the results show that the dissolution of 1,6-Hexanediol in the two binary solvents is an endothermic process.
研究领域:
物理化学
·
热力学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2022
·
IF 6.633
Yuanhui Chong,Qiong Liu,Zeqi Wang,Liukai Zhu,Fengxin Guo,Yu Li,Tao Li,Baozeng Ren
Perphenazine has rather effective in the treatment of mental illness. In this work, the solid-liquid equilibrium data of perphenazine in eleven organic neat solvents were determined by laser dynamic method under the atmospheric pressure and temperature range of 278.15 K ∼ 318.15 K. The selected solvents were n-propanol, n-butyl alcohol, methyl acetate, ethyl acetate, n-propyl acetate, n-amyl acetate, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), acetone, 2-methoxyethanol, glycol ether, respectively. From the results, the solubility of perphenazine is all positively correlated with temperature. Separately, we have adopted the KAT-LSER model and molecular dynamics simulation to investigate the influence of solvent effects and solute-solvent interaction on solute solubility. Meanwhile, there were four activity coefficient models being used to correlate the solubility data and Average relative deviation of models are 4.13% (Margules model), 3.94% (NRTL model), 4.49% (NRTL-SAC model) and 3.06% (UNIQUAC model), respectively, all of which do not exceed 5%. It manifests that the four activity coefficient models can fit the experimental values well, in which the UNIQUAC model gives the best regression effect. Moreover, the apparent thermodynamic properties( △ sol G° , △ sol H° and △ sol S° ) of perphenazine in various solvents were calculated by Van’t Hoff equation. In accordance with the analysis and calculation of dissolution, the dissolution process is an endothermic entropy-driven process. This research can provide basic data for the crystallization process of perphenazine.
研究领域:
药学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Energy
·
2023
·
IF 9.3
Yuting Zhang,Bo Yin,Mingchan Ma,Boshi Cheng,Lin Zhu,Hongqiang Xu,Qian Wu,Shasha Tang,Haiyong He
Graphite anode for potassium-ion batteries suffers poor rate capability because of the sluggish diffusion kinetics of K + . According to the rate law of chemical reactions, enrichment of K + on the outer layer of graphite anode is expected to improve the rate capability. However, the surface of graphite is too smooth to adsorb adequate K + to enhance rate capability. Herein, MoS 2 is coated on exfoliated graphite to enrich the concentration of K + on the surface of EG by forming K 2 S in high-voltage region, leading to an extremely high diffusion coefficient of up to 1000 times than that of bare graphite at the bottleneck stage, which accelerates the reaction rate of electrochemical intercalation process. Consequently, the EG/MoS 2 electrode exhibits superior rate performances (125 mAh/g at 3.2 A/g), which is 11 times higher than that of EG. Moreover, the specific capacity of EG/MoS 2 is 169 mAh/g at 1.6 A/g below 0.36 V, which is almost 25 times higher than that of bare EG (7 mAh/g). Our study provides new fundamental insights to boost power density of the anodes for PIBs without trading off energy density .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Jiangping Jing,Zhuoyuan Chen,Chang Feng,Mengmeng Sun,Jian Hou
Photoelectrochemical cathodic protection is emerging as a green and environmental method to protect metals against corrosion. Graphitic carbon nitride (g-C 3 N 4 ) shows great application potential in this area because of its high efficiency, high stability and low cost. However, the pristine g-C 3 N 4 shows amphoteric properties, resulting in its failure in providing photoelectrochemical cathodic protection for the coupled metal in NaCl solution. In this work, a K&I co-doping technique was performed to modulate the band structure of g-C 3 N 4 , and an n-type g-C 3 N 4 (n-C 3 N 4 ) was obtained. The changes in the molecular structure were studied by SEM, HRTEM , XRD , EDS, XPS and FT-IR technologies. The n-type semiconductor characteristics were verified by the photoinduced i-V curves, SKP potential distributions and pH drift techniques. The n-C 3 N 4 can generate positive photocurrent in the whole investigated potential range, making it able to provide photoelectrochemical cathodic protection for the coupled 316L stainless steel in NaCl solution. This work is very helpful for promoting the application of g-C 3 N 4 in the fields of the photoelectric conversion and the photoelectrochemical cathodic protection.
研究领域:
材料科学
·
腐蚀与防护
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）