JOURNAL OF RARE EARTHS
·
2015
·
IF 1.261
Mengting LI,Baoxiang JIAO
ZnTiO 3 :Eu 3+ phosphors were synthesized with different concentrations of Eu 3+ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Raman and photoluminescence spectroscopy. The XRD results showed that the ZnTiO 3 :Eu 3+ phosphors doped with different concentrations of Eu 3+ ions calcined at 600 °C were of single phase, which indicated that the Eu 3+ ions had been successfully incorporated into the ZnTiO 3 host lattice and did not destroy the lattice structure of ZnTiO 3 host. The Raman spectrum, SEM and TEM also proved that the doping of Eu 3+ did not change the lattice structure of hexagonal ZnTiO 3 host. The photoluminescence (PL) of Eu 3+ ions with the main emission peak at 614 nm was observed to increase with Eu 3+ concentrations from 0.5 mol.% to 2.0 mol.% and decreased when the concentration was increased to 2.5 mol.%. The decrease in the PL intensity at higher Eu 3+ concentrations could be associated with concentration quenching effect. The CIE1931 chromaticity diagram ( x , y ) of ZnTiO 3 :2.0 wt.%Eu 3+ phosphors were located in the red region ( x =0.652, y =0.347). The luminescence properties suggested that ZnTiO 3 :Eu 3+ phosphors might be regarded as a potential red phosphor candidate for light emitting diodes (LEDs).
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2013
·
IF 1.304
Yi Hu,Xiangjun Jiang,Suwen Wu,Ling Jiang,He Huang
Vitamin E succinate was synthesized by interfacial activated Candida rugosa lipase (CRL) encapsulated in sol-gel materials. The effects of various immobilization parameters were investigated. The optimum conditions were found to consist of n -propyltrimethoxysilane/tetraethoxysilane molar ratio = 1/1, water/silane molar ratio ( R value) = 20, lipase loading = 0.5 mg/ml sol, and PEG400 loading = 12 μl/ml sol. Compared with free enzymes, sol-gel encapsulated enzymes kept its activity of 70.58% and achieved 2.6-fold increased stability after 18 h incubation in phosphate buffer (0.025 mol/L, pH = 7.0) at 50 °C. Based on the interfacial characteristics of CRL, five kinds of surfactants were used for activation. The results demonstrate that olive oil was the most effective in activating CRL. The esterification activity of vitamin E succinate synthesis by interfacial activated CRL encapsulated in sol-gel materials reached up to 6.7-fold and 1.43-fold that of free enzyme and non-interfacial activated enzyme, respectively.
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高影响因子
Journal of Energy Chemistry
·
2015
·
IF 2.352
Feifei Sun,Yue An,Lecheng Lei,Fuying Wu,Jingke Zhu,Xingwang Zhang
Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393–503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rate-limiting step during the period, in which the conversion of carbazole was less than 40%. The hydrogenation process followed pseudo-first-order kinetics and the hydrogenation activation energies of carbazole and N-ethylcarbazole were 90 kJ/mol and 115 kJ/mol, respectively. The reaction starting position as well as the pathway of the hydrogenation of (N-ethyl)carbazole were investigated by comparing the kinetic characteristics of hydrogen uptake of carbazole and N-ethylcarbazole. The results showed that the reaction was a stepwise hydrogenation process and the first H 2 was added to the C1 = C10 double bond in the hydrogenation.
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高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2015
·
IF 0.754
Fu-Xing XU,Qian-Kun DANG,Yin-Juan CHEN,Kai YANG,Qiang WANG,Bin CHEN,Yuan-Yuan WANG,Chuan-Fan DING
A fast mass analysis method using digital ion trap technology was reported. The mass analysis was realized by scanning the frequency of digital RF voltage and dipole ion resonance voltage during ion injection period without the conventional ion cooling, ion resonance ejection or ion cleaning process. It can decrease about three fourth of traditional analysis time using ion trap mass spectrometry. The ion signal was optimized through the modification of frequency scanning rate, ion gate voltage and other experimental parameters. For example, an optimal mass spectroscopy of reserpine ( m / z 609) and arginine ( m / z 174) were obtained when the ion gate voltage was 9 V and the digital RF frequency was scanned from 1 MHz to 400 kHz at rate of 2385 Th s −1 . The results indicated that the obtained mass spectra were in very good agreement with conventional analytical method using ion trap mass analyzer.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Junjie Zhang,Fang Lu,Weiqiang Yu,Rui Lu,Jie Xu
Lactic acid is produced as a major byproduct during sorbitol hydrogenolysis under alkaline conditions. We investigated the effects of two different alkaline additives, Ca(OH) 2 and La(OH) 3 , on lactic acid formation during sorbitol hydrogenolysis over Ni/C catalyst. In the case of Ca(OH) 2 , the selectivity of lactic acid was 8.9%. In contrast, the inclusion of La(OH) 3 resulted in a sorbitol conversion of 99% with only trace quantities of lactic acid being detected. In addition, the total selectivity towards the C2 and C4 products increased from 20.0% to 24.5% going from Ca(OH) 2 to La(OH) 3 . These results therefore indicated that La(OH) 3 could be used as an efficient alkaline additive to enhance the conversion of sorbitol. Pyruvic aldehyde, which is formed as an intermediate during sorbitol hydrogenolysis, can be converted to both 1,2-propylene glycol and lactic acid by hydrogenation and rearrangement reactions, respectively. Notably, these two reactions are competitive. When Ca(OH) 2 was used as an additive for sorbitol hydrogenolysis, both the hydrogenation and rearrangement reactions occurred. In contrast, the use of La(OH) 3 favored the hydrogenation reaction, with only trace quantities of lactic acid being formed.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Yanke Yu,Jinsheng Chen,Jinxiu Wang,Yanting Chen
A series of CuSO 4 /TiO 2 catalysts were prepared using a wet impregnation method. The activity of each sample in the selective catalytic reduction of NO by NH 3 (NH 3 -SCR) was determined. The effects of SO 2 and H 2 O, and their combined effect, on the activity were examined at 340 °C for 24 h. The catalysts were characterized using N 2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction of H 2 (H 2 -TPR), temperature-programmed desorption of NH 3 (NH 3 -TPD), and in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). The CuSO 4 /TiO 2 catalysts had good activities, with low production of N 2 O above 340 °C. SO 2 or a combination of SO 2 and H 2 O had little effect on the activity, and H 2 O caused only a slight decrease in activity during the experimental period. The NH 3 -TPD and H 2 -TPR results showed that CuSO 4 increased the amounts of acid sites and adsorbed oxygen on the catalyst. In situ DRIFTS showed that the NH 3 -SCR reaction on the CuSO 4 /TiO 2 catalysts followed an Eley–Rideal mechanism. The reaction of gaseous NO with NH 3 adsorbed on Lewis acid sites to form N 2 and H 2 O could be the main reaction pathway, and oxygen adsorption might favor this process.
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高影响因子
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
·
2016
·Vol. 26
·期 7
·075011
·
IF 1.768
Zhanxiao Kang,Tiantian Kong,Leyan Lei,Pingan Zhu,Xiaowei Tian,Liqiu Wang
The controlled generation of microparticles with non-spherical features is of increasing importance. Such particles are useful for fundamental studies in areas such as self-assembly, as well as biomedical applications from drug carriers to photonic devices. We propose a simple model that captures the dominating factors controlling the size and morphology of non-spherical particles from phase separated droplets. The validity of our model is verified by comparing the generated non-spherical microparticles by droplet microfluidics. This simple relationship between the dominating factors and the final morphologies enables the production of non-spherical particles with well-defined shapes and tightly-controlled dimensions for a variety of applications from drug delivery vehicles to structural materials.
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高影响因子
Chinese Physics B
·
2016
·Vol. 25
·期 7
·078106
·
IF 1.436
Xu Yan,Miao Yu,Wen-Peng Han,Ming-Hao You,Jun-Cheng Zhang,Rui-Hua Dong,Hong-Di Zhang,Yun-Ze Long
Electrospun nanofibers with designed or controlled structures have drawn much attention. In this study, we report an interesting new closed-loop structure in individual cerium nitrate/polyvinyl alcohol (Ce(NO3)3/PVA) and NaCl/PVA fibers, which are fabricated by electrospinning with a nail collector. The electrospinning parameters such as voltage and Ce(NO3)3 (or NaCl) concentration are examined for the formation of the closed-loop structure. The results suggest that the increase of the spinning voltage or addition of Ce(NO3)3 (or NaCl) is favorable for the formation of the closed-loop structure, and the increase of loop numbers and the decrease of loop size. Further analyses indicate that the formation mechanism of the closed-loop fibers can be predominantly attributed to the Coulomb repulsion in the charged jets.
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高影响因子
Materials Research Express
·
2016
·Vol. 3
·期 7
·075024
·
IF 0.968
Shiben Liu,Yingjie Chen,Lifeng Dong
Hybrid nanostructures can be multifunctional and even possess enhanced properties. Ag–Fe2O3 nanocomposites and Ag nanoparticles (NPs) were fabricated and applied to catalyze the reduction of 4-nitrophenol. Compared with Ag NPs, Ag–Fe2O3 nanocomposites demonstrated enhanced catalytic activities. Furthermore, due to their magnetic properties, Ag–Fe2O3 nanocomposites could be easily separated from the reaction mixture and recycled through an external magnetic field. These findings will help us design hybrid nanostructures with catalytic activity and explore other potential applications of magnetic nanocomposites.
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高影响因子
Chinese Journal of Natural Medicines
·
2016
·
IF 1.382
Feng ZHANG,Liang SUN,Shou-Hong GAO,Wan-Sheng CHEN,Yi-Feng CHAI
Tanreqing injection (TRQ), a well-known traditional Chinese medicine formula, is commonly used to treat respiratory diseases. In the present study, a rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determinate the plasma contents of 5 major constituents of TRQ, including chlorogenic acid (CHA), caffeic acid (CFA), baicalin (BA), ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in rats after intravenous administration of TRQ. Chromatographic separation was performed on an Agilent Zorbax SB-C 18 column (3.5 μm, 100 mm × 2.1 mm), with acetonitrile and 0.1% aqueous formic acid as mobile phase at a flow rate of 0.3 mL·min −1 . The calibration curves were linear over the ranges of 27.0–13 333.0 ng·mL −1 for CFA, 30.0–14 933.0 ng·mL −1 for CHA, 50.0–50 333.0 ng·mL −1 for BA, 550.0–55 000.0 ng·mL −1 for UDCA, and 480.0–48 000.0 ng·mL −1 for CDCA, respectively. Intra- and inter-day precisions (relative standard deviations, RSDs) were from 3.11% to 14.08%. The extraction recoveries were greater than 71% and accuracy (relative recovery) was from 89% to 137% for all analytes, except endogenous bile acids. This validated method was successfully applied to the first pharmacokinetic study of CFA, CHA, BA, UDCA and CDCA in rat plasma after intravenous administration of TRQ.
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PubMed
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Xinping Duan,Yan Yin,Xuelin Tian,Jinhuo Ke,Zhaojun Wen,Jianwei Zheng,Menglin Hu,Linmin Ye,Youzhu Yuan
Disintegration or redispersion of supported sintered gold nanoparticles (Au NPs) in the presence of alkyl halide can give catalyst regeneration or redispersion of sintered Au catalysts. The selectivity of alkyl halides, temperature and size distributions were investigated to elucidate the redispersion of Au NPs during halide-induced decomposition. This study proved that the alkyl halide induced the redispersion of sintered Au NPs which depended on the R–X (X = I, Br, Cl) bond dissociation energy (BDE) and thus provided a simple descriptor for the regeneration of inactive supported Au catalysts. A correlation between the BDE of R–X and dispersion efficiency was established. The tendency for disintegration and redispersion followed the R–X BDE of the alkyl halide. Compared to alkyl chlorides and bromides, iodides were more efficient for redispersing sintered Au NPs. As a descriptor, the BDE of R–I played a crucial role in particle redispersion. These findings provided insights into the mechanism of organic halide-induced Au NP disintegration and the effect of the halide type on the redispersion of sintered catalysts.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Chaochen Wang,Wangxin Ge,Lei Tang,Yanbin Qi,Lei Dong,Hongliang Jiang,Jianhua Shen,Yihua Zhu,Chunzhong Li
ABSTRACT Metal single-atom/atomic cluster catalysts (SA/AC) have emerged as effective electrocatalysts for the CO 2 reduction reaction (CO 2 RR) due to their high metal atom utilization and controllable metal coordination environments. However, the designing and tuning of the local electronic environments of SA/AC ensembles remain a significant challenge. In this work, we develop a single-atom-modified atomic cluster copper catalyst (Cu SA/ACs) for CO 2 RR. The SA/AC-induced modulation of the local electronic structure enhances CO 2 adsorption on the atomic cluster; additionally, the atomic cluster provides abundant active hydrogen for CO 2 protonation by mediating hydrolysis dissociation on the SAs. Consequently, compared to copper single-atom catalysts (Cu SACs), the Cu SA/ACs exhibit significantly improved activity, the current is 3.6 times that of Cu SACs, and the Faradaic efficiency of CO rose from 27.15% to 98.94%. The Cu SA/ACs catalyst can efficiently reduce CO 2 to CO in flow-cell configuration, and the CO selectivity is 93.06% at a current density of 600 mA cm –2 . The maximum energy efficiency of the cathode is 61.9%, which is superior to that of most CO 2 -to-CO catalysts. This work provides a new perspective for developing efficient SA/AC catalysts.
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高影响因子
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