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1.
《Physics letters. A》2020,384(31):126791
It is shown that the specific heat of a few-fermion system with odd number fermions behaves differently from that of a few-fermion system with even number fermions. The specific heat of an even-number-fermion system behaves like a Bose one rather than a Fermi one. 相似文献
2.
Changyong Sun Guangzong Fang Xiaoguang Guo Yuanli Hu Shuqi Ma Tianhua Yang Jie Han Hao Ma Dali Tan Xinhe Bao 《天然气化学杂志》2015,(3):257-263
Long-term stability test of Mo/HZSM-5-N catalysts(HZSM-5-N stands for nano-sized HZSM-5) in methane dehydroaromatization(MDA)reaction has been performed with periodic CH4-H2 switch at 1033-1073 K for more than 1000 h.During this test,methane conversion ranges from 13% to 16%,and mean yield to aromatics(i.e.benzene and naphthalene) exceeds 10%.N2-physisorption,XRD,NMR and TPO measurements were performed for the used Mo/HZSM-5 catalysts and coke deposition,and the results revealed that the periodic hydrogenation can effectively suppress coke deposition by removing the inert aromatic-type coke,thus ensuring Mo/HZSM-5 partly maintained its activity even in the presence of large amount of coke deposition.The effect of zeolite particle size on the catalytic activity was also explored,and the results showed that the nano-sized zeolite with low diffusion resistance performed better.It is recognized that the size effect was enhanced by reaction time,and it became more remarkable in a long-term MDA reaction even at a low space velocity. 相似文献
3.
Guang Huang Hui-Ran Zhao Qing-Qing Meng Wen Zhou Qi-Jing Zhang Jin-Yun Dong Jia-Hua Cui Shao-Shun Li 《中国化学快报》2017,28(7):1553-1558
6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones (6-DMNQ), the promising anticancer scaffolds, were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields. An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring, regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation. The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells. Moreover, most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones, which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents. 相似文献
4.
Unlike taking the same external electrical stimulation to discuss chaotic synchronization in the literature, the synchronization between two uncouple FitzHugh?CNagumo (FHN) neurons with different ionic currents and external electrical stimulations is considered. The main contribution of this study is the application of a robust adaptive sliding-mode controller instead of the active elimination. The proposed sliding mode controller associated with time varying feedback gains cannot only tackle the system uncertainties and external disturbances, but also compensate for the mismatch nonlinear dynamics of synchronized error system without direct cancellation. Meanwhile, these feedback gains are not determined in advance but updated by the adaptive laws. Sufficient conditions to guarantee the stable synchronization are given in the sense of the Lyapunov stability theorem. In addition, numerical simulations are also performed to verify the effectiveness of presented scheme. 相似文献
5.
A rapid kinetic method for the simultaneous determination of levodopa, dopamine, and dobutamine was examined and developed.
It was based on a consecutive reaction of a reduction of Cu(II) to Cu(I) by catecholamines, followed by the complexation of
Cu(I) with neocuproine to form a yellow product in an acetic acid-acetate buffer. Spectrophotometric data were recorded at
453 nm (wavelength at the yellow complex absorption maximum) for 300 s. Linear calibrations were obtained in the concentration
ranges of (0.08–1.44) × 10−5 mol L−1, (0.08–1.44) × 10−5 mol L−1, and (0.16–1.44) × 10−5 mol L−1 for levodopa, dopamine, and dobutamine, respectively. A variety of multivariate calibration models was developed for simultaneous
analysis of the three analytes; while most models produced satisfactory prediction results for synthetic samples, the hybrid
linear analysis method was arguably the best-performing (relative prediction error, RPET = 6.6 %). The proposed method was
applied to an analysis of spiked rabbit serum samples and the results showed good agreement with the high performance liquid
chromatography measurements. 相似文献
6.
Molecular orbital calculations of some extended sesquifulvalene compounds as On with olefins bridge and Tn with thiophenes bridge as well as their corresponding cyclopentadienyl‐iron(II) coordination compounds as IOn and ITn at the hybrid density functional theory level demonstrate that the dipole moment depends linearly on the molecular size (n), and the linear polarizability depends linearly on n2 as well as the first hyperpolarizability also has a linear dependence on n3. 相似文献
7.
Early diagnosis is the key to the effective treatment of cancer. The detection of cancer biomarkers plays a critical role not only in cancer early diagnosis, but also in classification and staging tumor progression, or assessment prognosis and treatment response. Currently, various molecular diagnostic techniques have been developed for cancer biomarker studies, with many of the more effective approaches requiring a separation step before detection. Capillary electrophoresis (CE) can perform rapid and efficient separation with small samples, which is well-suited for analysis of both small- and macro- molecule biomarkers in complex samples. CE has different separation modes and can couple to different detectors into a variety of platforms, such as conducting studies on DNA/ RNA point mutation, protein misexpression, and metabolite abnormality. Similarly, microchip capillary electrophoresis (MCE) appears as a very important biomarker screening platform with the merits of high throughput, integration, and miniaturization, which makes it a promising clinical tool. By hyphenated different detectors, or integrated with immunoassay, PCR/LDR and related technologies, MCE can be constructed into diverse platforms used in genomics, proteomics, and metabolomics study for biomarkers discovery. The multiplex biomarker screening approach via CE- or MCE-based platforms is becoming a trend. This paper focuses on studies of cancer biomarkers via CE/MCE platforms, based on the studies published over the past 3 years. Some recent CE applications in the field of cancer study, such as cancer theranostics, are introduced. 相似文献
8.
T.H. Meen C.J. Huang J.K. Tsai W.R. Chen L.W. Ji 《Journal of Physics and Chemistry of Solids》2011,72(6):653-656
In this research, dye-sensitized solar cells based on TiO2 micro-pillars fabricated by inductive couple plasma etcher were investigated by analyses of X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle, ultraviolet-visible absorption spectra (UV-vis), and current-voltage characteristics. X-ray diffraction patterns show that the TiO2 anatase phase forms while sintering at 450 °C for 30 min. The SEM images reveal that the diameter and height of TiO2 micro-pillars are about 3 and 0.8 μm, respectively. The measurements of contact angle between TiO2 micro-pillars and deionized water (DI water) reveal that the TiO2 micro-pillars is super-hydrophilic while annealed at 450 °C for 30 min.The absorption spectrum of TiO2 micro-pillars is better than TiO2 thin film and can be widely improved in visible region with N3 dye adsorbed. The results of current-voltage (I-V) characteristics analysis reveal that dye-sensitized solar cell with TiO2 micro-pillars electrode has better I-V characteristics and efficiency than TiO2 film electrodes. This result may be due to the annealed TiO2 micro-pillars applied on the electrode of dye-sensitized solar cell can increase the contact area between TiO2 and dye, resulting in the enhancement of I-V characteristics and efficiency for dye-sensitized solar cell. 相似文献
9.
《Tetrahedron letters》2014,55(4):877-879
Broussonetone A (1) and broussonetone B (2), two novel dimeric abietane diterpenes, have been isolated from Salvia broussonetii root cultures transformed by Agrobacterium rhizogenes. The structure of broussonetone A was determined from spectroscopic data and confirmed by X-ray analysis. This dimer can be formed by a [4+2]-cycloaddition of two molecules of 13β-hydroxyabieta-8(14),9(11)-dien-12-one. NMR data of broussonetone B indicated that the C-20 methyl in part B of the broussonetone A molecule had been substituted by an aldehyde group. Thus, broussonetone B could be formed by an analogous Diels Alder reaction between 13β-hydroxyabieta-8(14),9(11)-dien-12-one as the dienophile and its 20-oxo derivative as the electrophile. 相似文献
10.
Y. C. Chu J. R. Chen J. M. Tseng L. C. Tsai C. M. Shu 《Journal of Thermal Analysis and Calorimetry》2011,106(1):227-234
Di-tert-butyl peroxide (DTBP) is an organic peroxide (OP) which has widespread use in the various chemical industries. In the past,
thermal runaway reactions of OPs have been caused by their general thermal instability or by reactive incompatibility in storage
or operation, which can create potential for thermal decomposition reaction. In this study, differential scanning calorimetry
was applied to measure the heat of decomposition reactions, which can contribute to understand the reaction characteristics
of DTBP. Vent sizing package 2 was also employed to evaluate rates of increase for temperature and pressure in decomposition
reactions, and then the thermokinetic parameters of DTBP were estimated. Finally, hazard characteristics of the gassy system
containing DTBP, specifically with respect to thermal criticality, were clearly identified. 相似文献