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911.
The enhanced electrochemical stability of the synthesized hybrid catalyst has been demonstrated by the introduction of the synergistic effect between carbon powder additive and the prepared catalyst.Single crystal IrO 2 nanorod (SC-IrO 2 NR) catalyst was prepared by a sol-gel method.The structure and performance of the catalyst sample were characterized by X-ray diffraction spectroscopy (XRD),scanning electron microscope (SEM),transmission electron microscope (TEM),rotating disk electrode (RDE) and cyclic voltammetry (CV) measurements.XRD patterns and TEM images indicate that the catalyst sample has a rutile IrO 2 single crystal nanorod structure.The onset potential for oxygen reduction reaction (ORR) of the SC-IrO 2 NR-carbon hybrid catalyst specimen is 0.75 V (vs.RHE) in RDE measurement.CV and RDE test results show that the SC-IrO 2 NR-carbon hybrid catalyst has a better electrochemical stability in comparison with the commercial Pt/C catalyst,with attenuation ratios of 17.67% and 44.60% for the SC-IrO 2 NR-carbon hybrid catalyst and the commercial Pt/C catalyst after 1500 cycles,respectively.Therefore,in terms of stability,the SC-IrO 2 NR-carbon hybrid catalyst has a promising potential in the application of the proton exchange membrane fuel cell. 相似文献
912.
Sequential double fluorescent detections of total proteins and phosphoproteins in SDS‐PAGE 下载免费PDF全文
A fluorescent staining technique, using selective chelation with fluorophore and metal ion to the phosphate groups of phosphoproteins in SDS‐PAGE is described. As a fluorescent dye and a metal ion, Fura 2 pentapotassium salt and Al3+ were employed, respectively. The staining method, Fura 2 stain, has sensitivities of 16–32 ng of α‐casein and β‐casein, 62 ng of ovalbumin, phosvitin, and κ‐casein using an ultraviolet transilluminator. Furthermore, Fura 2 stain is able to carry out continuative double detection of total proteins and phosphoproteins on the same gel within 3.5 h. Consequently, selective phosphoprotein and total protein detections could be obtained without other poststaining. Considering the low cost, simplicity, and speed, Fura 2 staining may provide great practicalities in routine phosphoproteomics research. 相似文献
913.
Nonlinear Dynamics - Nonlinear behavior of bubbles, and most importantly $$\frac{1}{2}$$ -order subharmonics (SH), are used to increase the contrast-to-tissue ratio (CTR) in diagnostic ultrasound... 相似文献
914.
915.
X. H. Chen P. Li X. Y. Zhang Q. P. Wang Z. J. Liu Z. H. Cong L. Li H. J. Zhang 《Laser Physics》2011,21(12):2040-2044
A diode-end-pumped actively Q-switched eye-safe intracavity Raman laser at 1532 nm is demonstrated, with Nd:YVO4 as the laser crystal and BaWO4 as the Raman crystal. The highest average power of 1.5 W is obtained, with an incident pump of 12 W and a pulse repetition
rate of 35 kHz, corresponding to a diode-to-Stokes conversion efficiency of 12.5%. 相似文献
916.
Wang Zhixia Ni Zhengguo Cong Fuzhong Liu Xueshen Chen Lei 《Journal of Experimental and Theoretical Physics》2011,112(2):355-359
We study the chaotic dynamics in the Bose-Einstein condensate (BEC) system of a double lattice. Chaotic space-time evolution
is investigated for the particle number density in a BEC. By changing of the s-wave scattering length with a Feshbach resonance, the chaotic behavior can be well controlled to enter into periodicity.
Numerical calculation shows that there is periodic orbit according to the s-wave scattering length only if the maximal Lyapunov exponent of the system is negative. 相似文献
917.
918.
Huan Luo Yong‐Yi Zhao Xian‐Yi Jin Jian‐Mei Yang Hang Cong Qing‐Mei Ge Lin Sun Mao Liu Zhu Tao 《Electroanalysis》2020,32(7):1449-1458
A selective and sensitive modified‐electrode for catechol and dopamine was presented with supramolecular recognition accomplished by making use of the macrocyclic host multifarene[3,3] that was used as a composite with reduced graphene oxide. The morphologies and electrochemical nature of the composite were characterized by atomic force microscopy, transmission electron microscopy, cyclic voltammetry and differential pulse anodic voltammetry. The modified electrode, best operated at a potential around 0.16 V vs. Ag/AgCl, displayed a differential pulse voltammetric response in the linear concentration range of 10–100 nM within a detection limit of 0.51 nM (at S/N=3). It was further applied to detect dopamine (at a working potential of 0.18 V vs. Ag/AgCl) in the linear concentration range of 10–100 nM with a detection limit of 0.62 nM. The modified electrode also exhibited satisfactory results to the determination of dopamine injections. The constructed modified electrode for dopamine detection was investigated in the presence of the interfering substances including glucose, urea and ascorbic acid, indicating a good selectivity. 相似文献
919.
Christian Schroeder Christian Mück‐Lichtenfeld Le Xu Nicols A. Grosso‐Giordano Alexander Okrut Cong‐Yan Chen Stacey I. Zones Alexander Katz Michael Ryan Hansen Hubert Koller 《Angewandte Chemie (International ed. in English)》2020,59(27):10939-10943
Nests of three silanol groups are located on the internal pore surface of calcined zeolite SSZ‐70. 2D 1H double/triple‐quantum single‐quantum correlation NMR experiments enable a rigorous identification of these silanol triad nests. They reveal a close proximity to the structure directing agent (SDA), that is, N,N′‐diisobutyl imidazolium cations, in the as‐synthesized material, in which the defects are negatively charged (silanol dyad plus one charged SiO? siloxy group) for charge balance. It is inferred that ring strain prevents the condensation of silanol groups upon calcination and removal of the SDA to avoid energetically unfavorable three‐rings. In contrast, tetrad nests, created by boron extraction from B‐SSZ‐70 at various other locations, are not stable and silanol condensation occurs. Infrared spectroscopic investigations of adsorbed pyridine indicate an enhanced acidity of the silanol triads, suggesting important implications in catalysis. 相似文献
920.
Hideyuki Nakanishi Yuto Kawabata Shogo Tsujiai Hayato Tanaka Satoshi Teraji Gbor Holl Istvn Lagzi Tomohisa Norisuye Qui Tran‐Cong‐Miyata 《Angewandte Chemie (International ed. in English)》2020,59(31):13086-13092
The development of methods to pattern nanocrystals with different sizes and shapes remains a challenge. In this study, we demonstrate a unique class of bottom‐up approaches to assemble nanocrystals into patterns. Our approach for patterning nanocrystals focuses on the utilization and control of the chemical reaction of solvents surrounding nanocrystals. The photopolymerization of solvent molecules through a photomask creates time‐dependent concentration gradients of the solvents. Dispersed nanocrystals such as silver nanowires (AgNWs) migrate and are gradually organized and integrated into the polymerizing films based on the concentration gradients. The AgNW‐embedded film properties are determined by the organized AgNW structures and include light transmission and electrical conductivity. Overall, the demonstrated method is very simple, widely applicable to various nanocrystals and solvents, and can thus contribute to the development of a new class of nanocrystal patterning methods. 相似文献