JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2011
·Vol. 110
·期 3
·1437-1442
·
IF 1.752
Lan X. Z.,Pei H. R.,Yan X.,Liu W. B.
Phase behavior of dodecane–tetradecane ( n -C 12 H 26 –C 14 H 30 , n -C 12 –C 14 ) binary system in bulk and confined in SBA-15 (pore diameters 8 nm; 15.9 nm) has been investigated by differential scanning calorimetry and transmission electron microscopy. The bulk system possesses some special phases relating to the rotator phase in normal alkanes. Dodecane–tetradecane mixtures confined in SBA-15 (8 nm) are a system miscible both in solid and liquid states with a phase diagram of a smooth curve. Dodecane–tetradecane system confined in SBA-15 (15.9 nm) exhibits not only solid–liquid (s–l) in all compositions but solid–solid transition in mole fractions of tetradecane 0.1–0.6, which forms a phase diagram of “loop line” shape. Melting temperatures of n -C 12 –C 14 /SBA-15 (8 nm) are lower than those of n -C 12 –C 14 /SBA-15 (15.9 nm) in all mole fractions. The evolution of the phase diagram of n -C 12 –C 14 confined in 8 nm, 15.9 nm pore sizes of SBA-15 and in bulk, respectively, shows a dramatic effect of confinement on phase behavior of normal alkane mixtures. The s–l phase boundary lines of n -C 12 –C 14 /SBA-15 (8, 15.9 nm) are fitted as \( T_{\text{m,r}}^{x} \) being [ \( xT_{{\text{m} ,r}}^{A} + \left( {1 - x} \right)T_{\text{m,r}}^{B} - D \) ], where D is a polynomial ∑ a
i
x
i , i = 1, 2,···, n ( A = C 14 , B = C 12 ).
研究领域:
物理化学
·
材料科学
·
纳米限域效应
·
热分析
·
软物质物理
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
·
2019
·
IF 1.267
Yue Yang,Zihui Liu,Hao Chen,Shengqing Li
A simple and fast method of low-density solvent based dispersive liquid-liquid microextraction (LDS-DLLME) followed by high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been developed for the speciation analysis of organoarsenic and inorganic arsenic in water samples. The low-density solvent (octanol) was given as the organic phase and injected into the aqueous sample (donor phase) with methanol as the disperser. With As (V), As (III), p-APAA, 4-HPAA, ROX and PAA as target species, factors of LDS-DLLME including pH value, anionic carriers, elution conditions and extractant, were studied in detail. Besides, volumes of solvents were further optimised by response surface methodology. Under the optimal conditions, the limits of detection for four phenylarsenics and arsenate were in the range of 0.001–0.039 μg L−1. The relative standard deviations (RSDs) were 3.6–9.4% and the enrichment factors varied from 6.2 to 70.8. The proposed method of LDS-DLLME-HPLC-ICP-MS was satisfactorily applied to the determination of six arsenic compounds in water samples with recoveries of 81.8–111.7% for the spiked lake water samples.
研究领域:
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Nanomaterials
·
2018
·Vol. 2018
·期 1
·1465760
·
IF 2.207
Jiamao Li,Jingwei Hou,Yu Gong,Chengjian Xiao,Lei Yue,Linjie Zhao,Huan Ma,Heyi Wang,Shuming Peng,Chao Chen,Hongli Chen
A liquid-phase reducing method of synthesizing Pt nanocrystals was demonstrated, and dendrite-, cube-, and cuboctahedron-shaped Pt nanocrystals (NCs) with well-defined monomorphic were successfully synthesized through iodine ions mediated with the CTAB agent. When the KI concentration was increased to thirty times of K 2 PtCl 4 at the nucleation stage, the high-quality Pt nanodendrites could be obtained. However, no matter how many KI were added at the growth age, only cube- and cuboctahedron-shaped Pt nanocrystals formed. The results of high-resolution TEM, EDX, and XRD indicated that the size and shape of Pt NCs could be turned by changing the concentration and time of KI. In the nucleation stage, it might be due to that some iodine ions adsorb on the surfaces of Pt NCs, which probably cause the rapid growth process resulting in the formation of Pt nanodendrites. In the growth stage, although high concentrations of I − ions could contribute to the shape control and generate bigger particles of Pt NCs, small Pt particles do not grow into dendrites. The insight into the role of I − ions in synthesis of Pt NCs reported here provided a viewpoint for clearly understanding the formation mechanism of anisotropic platinum nanostructures.
研究领域:
纳米材料科学
·
物理化学
·
无机合成
·
催化化学
·
材料表征技术
✓ 已验证
DOI
高影响因子
Journal of Analysis and Testing
·
2018
·Vol. 2
·期 4
·332-341
·
IF 0
Wei Yin Hui,Li Xin Yu,Gao Jie,Liu Jia Jun,Yuan Dan,Yin Bin Cheng,Wang Jian
As an antibiotic, tetracycline has been widely used against bacterial infection or as feed additives for growth promotion, which may lead to the enrichment of antibiotic residues in animals or their products. Therefore, the detection of tetracycline is closely related to human health. The morphological transformation of CoOOH nanoflakes induced by tetracycline was monitored by scanning electron microscope images, dark-field light scattering images and optical spectra, which found that tetracycline could decompose CoOOH nanoflakes into small nanoparticles with low light scattering signal. As a result, the reduced light scattering of CoOOH nanoflakes was proportional to the increased concentration of tetracycline in the range of 1.0–250 μmol/L, and the limit of determination (LOD) was 0.23 μmol/L (3σ/k). Most foreign substances did not interfere in the analysis of tetracycline. Furthermore, the concentration of tetracycline in different milk samples detected with the standard addition method was so low that it accorded with the safety regulation, which was similar to the detection result with high-performance liquid chromatography (HPLC).
研究领域:
分析化学
·
纳米技术
·
食品安全
·
药物分析
✓ 已验证
产品关联
DOI
Revista Brasileira de Farmacognosia-Brazilian Journal of Pharmacognosy
·
2019
·Vol. 29
·期 1
·46-53
·
IF 1.754
Peng Wei,Han Ping,Yu Luyao,Chen Ying,Ye Bingzhu,Qin Luping,Xin Hailiang,Han Ting
The fruits of Xanthium strumarium L., Asteraceae, have been used for various diseases in Chinese folk medicine, including allergic rhinitis, tympanitis, arthritis, ozena etc. The current study was aimed to investigate the therapeutic effects of caffeoylquinic acids from fruits of X. strumarium on allergic rhinitis in animals. The toxicity test indicated that the caffeoylquinic acids have no obvious toxicity. By using HPLC assays combined with reference standards, ten caffeoylquinic acids were identified as the predominant constituents. Anti-allergic activities of the caffeoylquinic acids were evaluated using passive cutaneous anaphylaxis test and Schultz-Dale test; dimethylbenzene induced ear edema test was performed to evaluate its anti-inflammatory effect. Then, the allergic rhinitis model in rats was established to evaluate the therapeutic effects of the caffeoylquinic acids against allergic rhinitis with the following indexes: allergic rhinitis symptom scores, serum levels of pro-inflammatory cytokines, histopathological examination, and histamine release. Our study revealed that the caffeoylquinic acids showed obvious anti-allergic and anti-inflammatory properties, and its treatments were beneficial for ameliorating the nasal symptoms, decreasing pro-inflammatory cytokines, and inhibiting the releases of histamine. Collectively, the caffeoylquinic acids might be utilized as effective and safe disease therapeutic agents for allergic rhinitis.
研究领域:
药理学
·
免疫学
·
过敏
·
植物化学
✓ 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）