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641.
Zhang Y Li J Li Q Zhu L Liu X Zhong X Meng J Cao X 《Journal of colloid and interface science》2007,307(2):567-571
Electrospinning was employed to fabricate polymer-ceramic composite fibers from solutions containing poly(vinyl pyrrolidone) (PVP), Ce(NO(3))(3) x 6H(2)O and ZrOCl(2) x 8H(2)O. Upon firing the composite fibers at 1000 degrees C, Ce(0.67)Zr(0.33)O(2) fibers with diameters ranging from 0.4 to 2 microm were synthesized. These fibers exhibit strong resistance to sintering. They still have specific surface area around 11.8 m(2)/g after being heated at 1000 degrees C for 6 h. 相似文献
642.
Hydrogen release from ammonia borane (NH(3)BH(3), AB) can be greatly promoted by mechanical milling with magnesium nitride (Mg(3)N(2)). For example, a post-milled 6AB/Mg(3)N(2) sample started to release hydrogen from ~65 °C and gave a material-based hydrogen capacity of ~11 wt% upon heating to 300 °C. In addition to the improved dehydrogenation kinetics, the 6AB/Mg(3)N(2) sample also showed satisfactory performance in suppressing the volatile byproducts. X-ray diffraction, Fourier transform infrared spectroscopy and solid-state (11)B MAS NMR, as well as a series of designed experiments, were carried out to gain mechanistic understanding of the property improvements that arise from addition of Mg(3)N(2). Our study found that the formation of 3Mg(NH(2)BH(3))(2)·2NH(3), which is in single or mixed amidoborane ammoniate phases in nature, is an important mechanistic step in the dehydrogenation process of the 6AB/Mg(3)N(2) sample. 相似文献
643.
644.
Genome-Wide Identification of the Maize Calcium-Dependent Protein Kinase Gene Family 总被引:1,自引:0,他引:1
Pengda Ma Jingying Liu Xiangdong Yang Rui Ma 《Applied biochemistry and biotechnology》2013,169(7):2111-2125
In higher plants, calcium is a ubiquitous second messenger in eukaryotic signal transduction cascades. The plant-specific calcium-dependent protein kinases (CDPKs) play important roles regulating downstream components of calcium signaling. We conducted a genome-wide analysis of maize (Zea mays) CDPKs and identified 35 CDPK genes. Maize CDPKs were found to be similar to their counterparts in rice in gene structure, GC content and subgroup classification. Divergence time estimation suggested that maize–rice orthologs were largely consistent with the time when these two species diverged from the last common ancestor. Semiquantitative RT-PCR revealed that the 29 of total 35 maize CDPK genes were expressed in all tissues, including root, stem, leaf, tassel, ear, and kernel. Our genomic and bioinformatics analyses will provide an important foundation for further functional dissection of the maize CDPK gene family. 相似文献
645.
Qiang Hou Xiangdong Sun Youming Wang Baoxu Huang Zhen Jin 《Journal of Mathematical Analysis and Applications》2014
Animal diseases such as brucellosis and tuberculosis can be transmitted through an environmentally mediated mechanism, but the topics of most modeling work are based on infectious contact and direct transmission, which leads to the limited understanding of the transmission dynamics of these diseases. In this paper, we propose a new deterministic model which incorporates general incidences, various stages of infection and a general shedding rate of the pathogen to analyze the dynamics of these diseases. Under the biologically motivated assumptions, we derive the basic reproduction number R0, show the uniqueness of the endemic equilibrium, and prove the global asymptotically stability of the equilibria. Some specific examples are used to illustrate the utilization of our results. In addition, we elaborate the epidemiological significance of these results, which are very important for the prevention and control of animal diseases. 相似文献
646.
A method using the time reversal(TR) technique to measure the insertion loss(IL) of passive materials is presented.Firstly the received signals are focused according to the TR theory when there is not a sample between the source and the received array.Then,the sample is placed near the received array and the TR processing is again employed to realize the focus of the received signal.Finally,the IL of the sample is evaluated from these focusing signals.Because the TR processing can focus the energy in spatial domain and time domain,the method can be used to measure acoustic properties of passive materials in a waveguide tank with reflections induced by boundaries or with low source frequencies.Two samples with the same size of 1.1 m×1.0 m×5 mm are tested in the waveguide tank.The method is demonstrated by the comparison of the theoretical and the experimental results in the measured frequency range of 1-20 kHz. 相似文献
647.
648.
Chen Qingtao Yang Maosen Chen Fenghua Zhang Zhaoqian Liang Weiwei Shi Xiangdong Zhang Yonghui Jiang Liying Fang Shaoming 《Journal of Solid State Electrochemistry》2023,27(3):739-751
Journal of Solid State Electrochemistry - Co4S3/Co9S8 nanosheets, Co-based sulfides with mixed crystalline phase, were first successfully prepared via solvothermal approach combined with ultrasonic... 相似文献
649.
Fuzhu Liu Peng-Fei Gao Chao Wu Prof. Shengchun Yang Prof. Xiangdong Ding 《Chemphyschem》2023,24(8):e202200642
The ensemble effect due to variation of Pd content in Pd−Au alloys have been widely investigated for several important reactions, including CO2 reduction reaction (CO2RR), however, identifying the stable Pd arrangements on the alloyed surface and picking out the active sites are still challenging. Here we use a density functional theory (DFT) based machine-learning (ML) approach to efficiently find the low-energy configurations of Pd−Au(111) surface alloys and the potentially active sites for CO2RR, fully covering the Pd content from 0 to 100 %. The ML model is actively learning process to improve the predicting accuracy for the configuration formation energy and to find the stable Pd−Au(111) alloyed surfaces, respectively. The local surface properties of adsorption sites are classified into two classes by the K-means clustering approach, which are closely related to the Pd content on Au surface. The classification is reflected in the variation of adsorption energy of CO and H: In the low Pd content range (0–60 %) the adsorption energies over the surface alloys can be tuned significantly, and in the medium Pd content (37-68 %), the catalytic activity of surface alloys for CO2RR can be increased by increase the Pd content and attributed to the meta-stable active site over the surface. Thus, the active site-dependent reaction mechanism is elucidated based on the ensemble effect, which provides new physical insights to understand the surface-related properties of catalysts. 相似文献
650.
Jun Zhao Kunshi Zhang Xinlu Cheng Xiangdong Yang 《Journal of Molecular Structure》2008,863(1-3):133-136
The CCN bond distances and bond dissociation energies (BDEs) are estimated by utilizing quantum chemical calculations for 16 nitrile compounds. Since DFT methods have been researched to have low basis sets sensitivity for small and medium molecules in our earlier work [Jun Zhao, Xinlu Cheng, Xiangdong. Yang, J. Mol. Struct. (Theochem) 766 (2006) 87] 16 nitrile compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86) and the complete basis set (CBS-Q) method in conjunction with the 6-311G** basis set. The obtained results are compared with the available experimental data. It is demonstrated that CBS-Q method, which can produce reasonable BDEs for some systems, seems unable to predict accurate BDEs here. While, the B3P86 calculated results agree very well with the experimental values. So B3P86 method is suitable for computing the reliable BDEs of CCN bond for nitrile compounds. 相似文献