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排序方式: 共有221条查询结果,搜索用时 15 毫秒
181.
Li Lin Xiaoyang He Prof. Xia-Guang Zhang Dr. Wenchao Ma Biao Zhang Diye Wei Prof. Shunji Xie Qinghong Zhang Prof. Xiaodong Yi Prof. Ye Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202214959
The renewable-electricity-driven CO2 reduction to formic acid would contribute to establishing a carbon-neutral society. The current catalyst suffers from limited activity and stability under high selectivity and the ambiguous nature of active sites. Herein, we report a powerful Bi2S3-derived catalyst that demonstrates a current density of 2.0 A cm−2 with a formate Faradaic efficiency of 93 % at −0.95 V versus the reversible hydrogen electrode. The energy conversion efficiency and single-pass yield of formate reach 80 % and 67 %, respectively, and the durability reaches 100 h at an industrial-relevant current density. Pure formic acid with a concentration of 3.5 mol L−1 has been produced continuously. Our operando spectroscopic and theoretical studies reveal the dynamic evolution of the catalyst into a nanocomposite composed of Bi0 clusters and Bi2O2CO3 nanosheets and the pivotal role of Bi0−Bi2O2CO3 interface in CO2 activation and conversion. 相似文献
182.
Preparation, photocatalytic activities, and dye-sensitized solar-cell performance of submicron-scale TiO2 hollow spheres 总被引:1,自引:0,他引:1
Kondo Y Yoshikawa H Awaga K Murayama M Mori T Sunada K Bandow S Iijima S 《Langmuir : the ACS journal of surfaces and colloids》2008,24(2):547-550
We prepared submicron-scale spherical hollow particles of anatase TiO2 by using a polystyrene-bead template. The obtained particles were very uniform in size, with a diameter of 490 nm and a shell thickness of 30 nm. The Brunauer-Emmett-Teller surface area measurements revealed a large value of 70 m2/g. The photocatalytic property was investigated by the complete decomposition of gaseous isopropyl alcohol under UV irradiation. It was indicated that the activity of the hollow spheres was 1.8 times higher than that of the conventional P25 TiO2 nanoparticles with a diameter of 30 nm. Furthermore, we fabricated a dye-sensitized solar cell (DSC) using an electrode of the TiO2 hollow spheres, and examined the photovoltaic performance under simulated sunlight. Although the per-area efficiency was rather low (1.26%) because of a low area density of TiO2 on the electrode, the per-weight efficiency was 2.5 times higher than those of the conventional DSCs of TiO2. 相似文献
183.
184.
Poly(vinyl alcohol)-Congo Red (PVA-CR) complexes in aqueous solutions have a unique sol-gel transition behaviour. At an appropriate PVA concentration, a sol-gel-sol-gel type reentrant transition takes place with increasing CR concentration. The microscopic structure and Theological properties of these complexes were investigated by small-angle neutron scattering (SANS) and viscometry. 相似文献
185.
The binomial software reliability growth model (SRGM) contains most existing SRGMs proposed in earlier work as special cases, and can describe every software failure-occurrence pattern in continuous time. In this paper, we propose generalized binomial SRGMs in both continuous and discrete time, based on the idea of cumulative Bernoulli trials. It is shown that the proposed models give some new unusual discrete models as well as the well-known continuous SRGMs. Through numerical examples with actual software failure data, two estimation methods for model parameters with grouped data are provided, and the predictive model performance is examined quantitatively. 相似文献
186.
Guoqing Li Hitoshi Saito Shunji Ishio Toshiyuki Shima Koki Takanashi 《Journal of magnetism and magnetic materials》2006
Anomalous magnetization processes and non-symmetrical domain wall displacements in the minor loop of L10 FePt particulate films were investigated by magnetization measurements and in situ magnetic force microscopy. Magnetization (M) decreases dramatically on increasing the magnetic field to ∼3 kOe after which M becomes small and constant in the range of 5–20 kOe as observed in the successive measurement of minor loops. The domain wall displacement is non-symmetrical with respect to the field direction. The anomalous magnetization behavior was attributed to the non-symmetrical domain wall displacement and large magnetic field required for domain wall nucleation. Energy calculations from modeling suggest that non-symmetrical domain wall displacement is caused by the existence of metastable domains in which the domain edges are stuck to the particle boundaries. 相似文献
187.
This paper addresses the problem of how to determine optimal sleep timing when the computer user should turn the hard disk or the display off in order to save electric power after the computer has not been used. We propose a stochastic model to obtain an optimal sleep timing strategy which minimizes the expected power consumed per unit time in the steady state, where access requirements of the system occur in a renewal process and processing is described by a general service time. Phase type approximation is proposed to represent the expected power consumed per unit time. We investigate the performance of this approximation through a simulation study, and design an optimal auto-sleep schedule for a computer workstation system using real data. 相似文献
188.
Tsutomu Shinzawa Fumihiko Uesugi Iwao Nishiyama Kazumi Sugai Shunji Kishida Hidekazu Okabayashi 《应用有机金属化学》2000,14(1):14-24
A new type of precursor for aluminum chemical vapor deposition (Al‐CVD) has been developed by mixing dimethylaluminum hydride (DMAH) and trimethylaluminum (TMA). The new precursor has proven itself to be effective for Al‐CVD, where a good selectivity between the Si and the SiO2 mask, a 3.0 μΩ cm resistivity and a pure Al film with low C and O contamination levels (under 100 ppm) were achieved. Quadrupole mass and infrared absorption analysis have shown that the precursor contains a new molecular compound, consisting of a DMAH monomer and a TMA monomer. The mixture has lower viscosity than DMAH and can be easily bubbled for a stable precursor vapor supply. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
189.
190.
We consider a generalised ordering policy in which a spare unit for replacement can be delivered only by order after a constant lead time. Introducing the costs for ordering, shortage and holding, we derive the expected cost per unit time in the steady-state. We discuss the optimal ordering policy which minimises the expected cost, and show in a main theorem that the optimal policy is reduced to either one of two typical ordering policies depending on some conditions. We further discuss a similar ordering policy with varying lead times. 相似文献