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91.
Two distinctive carbon materials (Saran char and SP-1 graphite) were doped with B at different loading to clarify the intrinsic effect of substitutional B on carbon reactivity. The carbon precursors would be affected in different style by substitutional B due to different important properties (crystallinity and surface area). The B retentivity depended on the nature of B dopant and carbon substrate; a less ordered carbon has higher B loading than its counterpart. Graphitization was enhanced by substitutional B, as expected. Furthermore, the B incorporation was still beneficial for SP-1 although it already had high crystallinity. An interesting behavior was noticed; the increase in La was greater than Lc. The intrinsic effect of substitutional B in carbon oxidation was proved to be a catalytic one. Unlike highly ordered SP-1 graphite, Saran char showed both a catalytic effect at low B loading and low conversion, and an inhibiting effect at high B loading and high conversion. The inductive effect was proposed to explain this catalytic effect on different crystallite size. Different sizes of carbon clusters were calculated by Gaussian 98W; the extent of the effect of substitutional B did get smaller to the carbon in bigger size of carbon cluster. 相似文献
92.
Summary Introduction of isocyanate (NCO) group onto carbon black surface was achieved by the treatment of carbon black with toluene-2,4-diisocyanate. In addition, carbon black having acyl azide (CON3) group, a precursor of NCO group, was prepared by the reaction of COCl or COOCOOC2H5 group on carbon black with NaN3. The CON3 group on carbon black was relatively stable at below 20°C but readily decomposed to NCO group by heating (Curtius rearrangement). By the reation of NCO group on carbon black with hydroxyl group of polymers, such as polypropylene glycol, polyethylene glycol, and polyvinyl alcohol, these polymers were found to be grafted onto carbon black. 相似文献
93.
Masato Wakamura Hidekazu Tanaka Yasuo Naganuma Naoya Yoshida Toshiya Watanabe 《Advanced Powder Technology》2011,22(4):498-503
The synthetic titanium–calcium hydroxyapatite (Ti–CaHap) particles were treated with different concentrations of aqueous Cr(NO3)3·9H2O solution and the materials obtained were characterized by a variety of conventional techniques. The crystal structure and particle morphology of Ti–CaHap were essentially not altered by treating with Cr(III) solution. With increasing the Cr(III) concentration, the amount of Cr(III) in the products was increased and that of Ca(II) was decreased. XPS results revealed that the surface state of Cr of Ti–CaHap was trivalent. These facts allow us to infer that the Cr(III) was doped by substitution of surface Ca(II) of Ti–CaHap. Besides, IR results proved that increasing the Cr(III) concentration developed the surface Cr–OH band while the surface Ti–OH and P–OH bands of Ti–CaHap vanished. This imply that the formation of surface P–O-Cr(OH)2 and Ti–O–Cr(OH)2 groups, resulting the Cr(OH)3-like layer on the surface of Ti–CaHap particles. The Cr(III)-doped Ti–CaHap possessed the absorption peaks at 446 and 623 nm in vis range in addition to the UV absorption of charge transfer transition of O2? → Ti4+. The vis absorption peaks developed on raising the Cr(III) concentration. The photocatalytic decomposition of acetaldehyde into CO2 over Cr(III)-doped Ti–CaHap was detected under vis irradiation and the activity was lowered by the formation of Cr(OH)3-like layer on the particle surface. 相似文献
94.
Kaneko S Ito T Akiyama K Yasui M Kato C Tanaka S Hirabayashi Y Mastuno A Nire T Funakubo H Yoshimoto M 《Nanotechnology》2011,22(17):175307
After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min(-1) promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles. 相似文献
95.
96.
Effect of CO2 on layered Li1+zNi1−x−yCoxMyO2 (M = Al,Mn) cathode materials for lithium ion batteries
We investigated the effect of CO2 on layered Li1+zNi1−x−yCoxMyO2 (M = Al, Mn) cathode materials for lithium ion batteries which were prepared by solid-state reactions. Li1+zNi(1−x)/2CoxMn(1−x)/2O2 (Ni/Mn mole ratio = 1) singularly exhibited high storage stability. On the other hand, Li1+zNi0.80Co0.15Al0.05O2 samples were very unstable due to CO2 absorption. XPS and XRD measurements showed the reduction of Ni3+ to Ni2+ and the formation of Li2CO3 for Li1+zNi0.80Co0.15Al0.05O2 samples after CO2 exposure. SEM images also indicated that the surfaces of CO2-treated samples were covered with passivation films, which may contain Li2CO3. The relationship between CO2-exposure time and CO32− content suggests that there are two steps in the carbonation reactions; the first step occurs with the excess Li components, Li2O for example, and the second with LiNi0.80Co0.15Al0.05O2 itself. It is well consistent with the fact that the discharge capacity was not decreased and the capacity retention was improved until the excess lithium is consumed and then fast deterioration occurred. 相似文献
97.
Yoshimitsu Uemura Takami Kai Rintarou Natori Takeshige Takahashi Yasuo Hatate Masahiro Yoshida 《Renewable Energy》2004,29(4):581
A study was carried out to see if the potential of renewable energy sources other than hy droelectric power, such as wind, photovoltaic, solar thermal, biomass and waste energy sources, can meet the current energy consumption in Yakushima. The current electricity consumption can be covered by wind and photovoltaic energy sources. The total potential of wind and photovoltaic energy sources is 5.4 times as much as the current electricity consumption. LP gas and kerosene can be replaced by solar thermal and biogas energy. The potential of plant biomass and municipal waste is not sufficient (approximately one third) to cover the rest of the fossil fuels (gasoline, diesel oil and heavy oil). Also, plant biomass and municipal waste must be converted into fluid form. This shortage can be covered by the po tential of wind and photovoltaic energy sources. We also investigated the possibility of tourism expansion using the potential of wind and photovoltaic energy sources. Taking into account three types of capacity (energy, accommodation and transportation), Yakushima can accept approximately four times as many tourists as the current number of tourists. 相似文献
98.
Channel length dependence of field-effect mobility and source/drain parasitic resistance in pentacene thin-film transistors with a bottom-gate, bottom-contact configuration was investigated. Schottky barrier effect such as nonlinear behaviors in transistor output characteristics appeared and became more prominent for shorter channel length less than 10 μm, raising some concerns for a simple utilization of conventional parameter extraction methods. Therefore the gate-voltage-dependent hole mobility and the source/drain parasitic resistance in the pentacene transistors were evaluated with the aid of device simulation accounting for Schottky contact with a thermionic field emission model. The hole mobility in the channel region shows smaller values with shorter channel length even after removing the influence of Schottky barrier, suggesting that some disordered semiconductor layers with low carrier mobility exist near the contact electrode. This experimental data analysis with the simulation enables us to discuss and understand in detail the operation mechanism of bottom-gate, bottom-contact transistors by considering properly each process of charge carrier injection, carrier flow near the contact region, and actual channel transport. 相似文献
99.
Yasuo Y. Suzuki Shin-ichi Saito Susumu Kurihara 《Journal of Low Temperature Physics》1998,113(5-6):897-902
We investigated the ground state of the infinite dimensional Hubbard model for both attractive and repulsive interactions by applying Gutzwiller type variational wave functions. Our variational wave functions have lower energies than the simple BCS wave function for the attractive case, and lower energies than the Brinkman-Rice state for the repulsive case. We found that the system has several phases depending on the density of electrons and the interaction strength. Investigated phases include antiferromagnetic, Fermi liquid, superconducting, charge density wave, and supersolid phases. The last one is a coexistence phase of superconducting and charge density wave states. 相似文献
100.