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81.
Wanjin Yu Yuzhan Xu Liuye Mo Hui Lou Xiaoming Zheng 《Reaction Kinetics and Catalysis Letters》2009,98(2):303-309
Ni–La2O3/SiO2 catalysts (NLS) were prepared by the incipient-wetness impregnation method using EDTA salt precursors. XRD measurements revealed
that the promoter of La2O3 is highly dispersed on the NLS. The TPR profiles indicated a strong interaction between NiO and La2O3 to form a La–Ni complex oxide like species over the NLS, which may be the origin of its high catalytic performance. 相似文献
82.
采用有机凝胶法结合固相烧结技术制备了Sm0.9Sr0.1Al0.5Mn0.5O3-δ (SSAM9155)新型导电陶瓷. 通过TG/DTA, FTIR, XRD, SEM和直流四引线法系统研究了凝胶前驱体的热分解及其相转化过程和烧结体的结构、相稳定性、微观形貌、电导率以及电输运机制. 结果表明, 凝胶前驱体在900 ℃焙烧5 h可以形成完全晶化的四方钙钛矿相纳米粉体; 高温烧结制得的SSAM9155陶瓷的电导率取决于p型电导, 电导率随温度的升高而增大, 导电行为符合p型小极化子跳跃机制; 随烧结温度的升高或保温时间的延长, SSAM9155陶瓷的电导率和相对密度都先增大后减小, 1600 ℃烧结10 h制得的SSAM9155陶瓷具有最高的电导率和相对密度(98%), 该样品在空气和氢气气氛中850 ℃时的电导率分别为8.21和1.26 S•cm-1, 表观活化能分别为0.265和0.465 eV. 具有较高电导率的Sr, Mn掺杂的SmAlO3导电陶瓷有望成为一种新型的固体氧化物燃料电池(SOFC)阳极材料. 相似文献
83.
Xing‐Long Lou Fa Cheng Prof. Peng‐Fei Cao Qiang Tang Hua‐Ji Liu Dr. Yu Chen Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(43):11566-11572
Hyperbranched polyethylenimine (HPEI) was simply mixed with a solution of amphiphilic calix[4]arene (AC4), which possesses four phenol groups and four aliphatic chains, in chloroform. This resulted in the novel supramolecular complex HPEI–AC4 through the noncovalent interaction of the amino groups of HPEI with the phenol groups of AC4. The formed HPEI–AC4 supramolecular complexes were characterized by 1H NMR spectroscopy and dynamic light scattering. The cationic water‐soluble dye methyl blue (MB) and the anionic water‐soluble dye methyl orange (MO) were used as the model guests to test the performance of HPEI–AC4 as a supramolecular nanocarrier. It was found that HPEI–AC4 could accommodate the anionic water‐soluble MO guests into the HPEI core. The MO encapsulation capacity of HPEI–AC4 was pH sensitive, which reached maximum loading under weakly acidic conditions. The loaded MO molecules could be totally released when the pH value was reduced to be around 4.5 or raised to be around 9.5, and this process was reversible. HPEI–AC4 could not only accommodate the anionic MO with the HPEI core but could also simultaneously load the cationic MB molecules using the formed AC4 shell, thereby realizing the site isolation of the two kinds of functional units. The amount of MO and MB encapsulated by HPEI–AC4 could be controlled by varying the ratio of hydroxyl groups of AC4 to amino groups of HPEI. 相似文献
84.
Although various transition metal oxides have been reported to act as low potential Li insertion hosts, the oxyhydroxides have remained unexplored to date. We show here that the hydroxide ions present in transition metal oxyhydroxides do not interfere with the lithium uptake and extraction, permitting very good reversibility of the reduction/oxidation reactions. Goethite (α-FeOOH) nanocrystals can uptake and extract large amount of Li via the conversion reaction mechanism, providing a reversible capacity of 500 mA h g−1 at an average potential of 0.85 V vs. Li/Li+. The mechanism was examined using a combination of X-ray diffraction, electron microscopy, and the corresponding selected area electron diffractions (SAEDs). The α-FeOOH is reduced into nanoparticles of metallic Fe0 embedded in an amorphous matrix of Li2O and LiOH in the first discharge; the subsequent cyclings are redox reactions between metallic Fe0 and Fe2O3 clusters. 相似文献
85.
Robert Lindner Xinghua Lou Jochen Reinstein Robert L Shoeman Fred A Hamprecht Andreas Winkler 《Journal of the American Society for Mass Spectrometry》2014,25(6):1018-1028
Hydrogen–deuterium exchange (HDX) experiments analyzed by mass spectrometry (MS) provide information about the dynamics and the solvent accessibility of protein backbone amide hydrogen atoms. Continuous improvement of MS instrumentation has contributed to the increasing popularity of this method; however, comprehensive automated data analysis is only beginning to mature. We present Hexicon 2, an automated pipeline for data analysis and visualization based on the previously published program Hexicon (Lou et al. 2010). Hexicon 2 employs the sensitive NITPICK peak detection algorithm of its predecessor in a divide-and-conquer strategy and adds new features, such as chromatogram alignment and improved peptide sequence assignment. The unique feature of deuteration distribution estimation was retained in Hexicon 2 and improved using an iterative deconvolution algorithm that is robust even to noisy data. In addition, Hexicon 2 provides a data browser that facilitates quality control and provides convenient access to common data visualization tasks. Analysis of a benchmark dataset demonstrates superior performance of Hexicon 2 compared with its predecessor in terms of deuteration centroid recovery and deuteration distribution estimation. Hexicon 2 greatly reduces data analysis time compared with manual analysis, whereas the increased number of peptides provides redundant coverage of the entire protein sequence. Hexicon 2 is a standalone application available free of charge under http://hx2.mpimf-heidelberg.mpg.de. Figure
? 相似文献
86.
Xianwen Lou Christianus M. A. Leenders Arthur H. A. M. van Onzen Ralf A. A. Bovee Joost L. J. van Dongen Jef A. J. M. Vekemans E. W. Meijer 《Journal of the American Society for Mass Spectrometry》2014,25(2):297-300
Tetrahydrofuran (THF) is one of the most frequently used solvents in the MALDI TOF MS analysis of synthetic compounds. However, it should be used with caution because a trace amount of 4-hydroxybutanal (HBA) might be generated and accumulated in THF during storage. Since only a tiny amount of analytes is required in MALDI MS measurements, a trace amount of HBA might have a significant effect on the MS results. It was found that HBA will quickly react with primary and secondary amino compounds, leading to false results about the sample composition with an extra series of ions with additional mass of 70 Da in between. The formation of HBA can be inhibited by butylated hydroxytoluene (BHT) antioxidant. Therefore, when THF is required as the solvent for sample preparation, it is strongly recommended to use a BHT-stabilized one, at least for the analysis of compounds with amino groups. Figure
? 相似文献
87.
Soot particles characteristics were investigated numerically for high temperature oxidation of C2H4/O2/N2 (C/O ratio of 2.2) in a closed jet-stirred/plug-flow reactor (JSR/PFR) system. Based on the growth mechanism of polycyclic aromatic hydrocarbons (PAHs), two mechanisms were used to explore the formation pathways of soot precursors and soot. Numerical results were compared with the experimental and reference data. The simulation results show that the value predicted for small molecule intermediates within A1 gives a strong regularity, consistent trend with reference data. However, with the hydrogen-abstraction-carbon-addition (HACA) growth mechanism, the predicted value for beyond-A1 PAH macromolecules and soot volume fraction are smaller than the experimental data. The results also show that the predicted soot volume fraction is in good agreement with experimental data when a combination of the HACA and PAHs condensation (HACA + PAH-PAH) growth mechanisms is used. Analyses of the A1 sensitivity and reaction pathway elucidated that A1 are mainly formed from C2H3, C2H2, C3H3, C6H5OH, A1C2H and A1-. The reaction 2C3H3 → A1 is the dominant route of benzene formation. The prediction results and an analysis of the A3 reaction pathway indicate that the growth process from benzene to larger aromatic hydrocarbons (beyond two-ring polycyclic aromatic hydrocarbons [PAHs]) goes by two pathways, i.e., HACA combined with the PAH-PAH radical recombination and addition reaction growth mechanisms. 相似文献
88.
Zhijun Yuan Qihong Lou Jun Zhou Jingxing Dong Yunrong Wei Zhijiang Wang Hongming Zhao Guohua Wu 《Optics & Laser Technology》2009,41(4):380-383
The effect of laser fluence on the crystallization of amorphous silicon irradiated by a frequency-doubled Nd:YAG laser is studied both theoretically and experimentally. An effective numerical model is set up to predict the melting threshold and the optimized laser fluence for the crystallization of 200-nm-thick amorphous silicon. The variation of the temperature distribution with time and the melt depth is analyzed. Besides the model, the Raman spectra of thin films treated with different fluences are measured to confirm the phase transition and to determine the optimized fluence. The calculating results accord well with those obtained from the experimental data in this research. 相似文献
89.
Abstract
Nicotinamide crystallizes with 3-hydroxy-2-naphthoic acid and 4-aminobenzoic acid to give rise to cocrystal 1 and 2, respectively. Cocrystal 1, [C11H8O3][C6H6N2O], crystallizes in the monoclinic space group C2/c with a = 25.810(4), b = 4.8932(5), c = 23.869(4) ?, β = 107.078(8)o, V = 2881.6(7) ?3, Z = 8, C17H14N2O4, M r = 310.30, D c = 1.431 g/cm3. Cocrystal 2, [C7H7NO2][C6H6N2O]·H2O, crystallizes in the triclinic space group P-1 with a = 7.214(5), b = 7.326(5), c = 13.484(11) ?, α = 83.23(2), β = 77.189(18), γ = 80.35(2)o, V = 682.7(9) ?3, Z = 2, C13H15N3O4, M r = 277.28, D c = 1.349 g/cm3. Similar carboxylic acid···pyridine synthon R 22(7) can be observed in the two cocrystals. In 1, amide of nicotinamide forms a C(4) chain from the anti H to its carbonyl oxygen. In 2, the amide forms a R 22(8) homodimer which is linked into 2D layer by water molecule through different hydrogen-bonding interactions. The 3D hydrogen-bonded structure results from a synthon R 42(8) from amide, water and amino group of 4-aminobenzoic acid. 相似文献90.
Zi‐Jing Li Hong‐Xiang Lou Wen‐Tao Yu Pei‐Hong Fan Dong‐Mei Ren Bin Ma Mei Ji 《Helvetica chimica acta》2005,88(10):2637-2640
The known 7,8‐secolabdane type diterpenoids neopallavicinin ( 1 ), pallavicinin ( 2 ), and 18‐hydroxypallavicinin ( 3 ) were isolated from Pallavicinia ambigua, and their structures were determined. The X‐ray crystal structure of 1 was solved, and, in combination with CD and NMR studies, the absolute configurations of 1 – 3 were established. A possible biogenetic pathway for 1 and 2 from a single labdane precursor is proposed. 相似文献