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排序方式: 共有1319条查询结果,搜索用时 31 毫秒
41.
Exploitation of heterosis in rice(Oryza sativa L.) has contributed greatly to global food security.In this study,we generated three sets of reciprocal F1 hybrids of indica and japonica subspecies to evaluate the relationship between yield heterosis and the circadian clock.There were no differences in trait performance or heterosis between the reciprocal hybrids,indicating no maternal effects on heterosis.The indica-indica and indica-japonica reciprocal F1 hybrids exhibited pronounced heterosis for chlorophyll and starch content in leaves and for grain yield/biomass.In contrast,the japonica-japonica F1 hybrids showed low heterosis.The three circadian clock genes investigated expressed in an above-high-parent pattern(AHP)at seedling stage in all the hybrids.The five genes downstream of the circadian clock,and involved in chlorophyll and starch metabolic pathways,were expressed in AHP in hybrids with strong better-parent heterosis(BPH).Similarly,three of these Research Arfive genes in the japonica-japonica F1 hybrids showing low BPH were expressed in positive overdominance,but the other two genes were expressed in additive or negative overdominance.These results indicated that the expression patterns of circadian clock genes and their downstream genes are associated with heterosis,which suggests that the circadian rhythm pathway may be related to heterosis in rice. 相似文献
42.
Synthesis of fluorescent and low cytotoxicity phenol formaldehyde resin (PFR)@Ag composites for cell imaging and antibacterial activity 下载免费PDF全文
Ping Yang Hao Dong Jun Xia Andong Xu Jianjun Shi Jie He Jianzhong Ding Dewei Li 《Luminescence》2015,30(8):1413-1417
Ag nanoparticles (NPs) were loaded onto the surface of phenol formaldehyde resin (PFR) NPs without any reducing agent. The as‐synthesized PFR@Ag composites have low cytotoxicity, which makes them promising antibacterial agents. Furthermore, the good fluorescence of PFR could be used for cell imaging. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
43.
Ce3+/Eu2+ co‐doped Na3Ca6(PO4)5 phosphors were prepared using a combustion‐assisted synthesis method. X‐Ray powder diffraction (XRD) analysis confirmed the formation of a Na3Ca6(PO4)5 crystal phase. Na3Ca6(PO4)5:Eu2+ phosphors have an efficient bluish‐green emission band that peaks at 489 nm, whereas Ce3+‐doped Na3Ca6(PO4)5 showed a bright emission band at 391 nm. Analysis of the experimental results suggests that enhancement of the Eu2+ emission intensity in co‐doped Na3Ca6(PO4)5:Eu2+,Ce3+ phosphors is due to a resonance‐type energy transfer from Ce3+ to Eu2+ ions, which is predominantly governed by an exchange interaction mechanism. These results indicate that Ce3+/Eu2+ co‐doped Na3Ca6(PO4)5 is potentially useful as a highly efficient, bluish‐green emitting, UV‐convertible phosphor for white‐light‐emitting diodes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
44.
Low‐Temperature Micro‐Solid Oxide Fuel Cells with Partially Amorphous La0.6Sr0.4CoO3‐δ Cathodes 下载免费PDF全文
Anna Evans Julia Martynczuk Dieter Stender Christof W. Schneider Thomas Lippert Michel Prestat 《Liver Transplantation》2015,5(1)
Partially amorphous La0.6Sr0.4CoO3‐δ (LSC) thin‐film cathodes are fabricated using pulsed laser deposition and are integrated in free‐standing micro‐solid oxide fuel cells (micro‐SOFC) with a 3YSZ electrolyte and a Pt anode. A low degree of crystallinity of the LSC layers is achieved by taking advantage of the miniaturization of the cells, which permits low‐temperature operation (300–450 °C). Thermomechanically stable micro‐SOFC are obtained with strongly buckled electrolyte membranes. The nanoporous columnar microstructure of the LSC layers provides a large surface area for oxygen incorporation and is also believed to reduce the amount of stress at the cathode/electrolyte interface. With a high rate of failure‐free micro‐SOFC membranes, it is possible to avoid gas cross‐over and open‐circuit voltages of 1.06 V are attained. First power densities as high as 200–262 mW cm?2 at 400–450 °C are achieved. The area‐specific resistance of the oxygen reduction reaction is lower than 0.3 Ω cm2 at 400 °C around the peak power density. These outstanding findings demonstrate that partially amorphous oxides are promising electrode candidates for the next‐generation of solid oxide fuel cells working at low‐temperatures. 相似文献
45.
Recent Progress on Hole‐Transporting Materials for Emerging Organometal Halide Perovskite Solar Cells 下载免费PDF全文
In less than three years, the photovoltaic community has witnessed a rapid emergence of a new class of solid‐state heterojunction solar cells based on solution‐processable organometal halide perovskite absorbers. The energy conversion efficiency of solid‐state perovskite solar cells (PSCs) has been quickly increased to a certified value of 20.1% by the end of 2014 because of their unique characteristics, such as a broad spectral absorption range, large absorption coefficient, high charge carrier mobility and diffusion length. Here, the focus is specifically on recent developments of hole‐transporting materials (HTMs) in PSCs, which are essential components for achieving high solar cell efficiencies. Some fundamentals with regard to PSCs are first presented, including the history of PSCs, device architectures and general operational principles of PSCs as well as various techniques developed for the fabrications of uniform and dense perovskite complexes. A broad range of the state‐of‐the‐art HTMs being used in PSCs are then discussed in detail. Finally, an outlook on the design of more efficient HTMs for highly efficient PSCs is addressed. 相似文献
46.
Qian Zhang Eyob Kebede Chere Jingying Sun Feng Cao Keshab Dahal Shuo Chen Gang Chen Zhifeng Ren 《Liver Transplantation》2015,5(12)
Iodine‐doped n‐type SnSe polycrystalline by melting and hot pressing is prepared. The prepared material is anisotropic with a peak ZT of ≈0.8 at about 773 K measured along the hot pressing direction. This is the first report on thermoelectric properties of n‐type Sn chalcogenide alloys. With increasing content of iodine, the carrier concentration changed from 2.3 × 1017 cm?3 (p‐type) to 5.0 × 1015 cm?3 (n‐type) then to 2.0 × 1017 cm?3 (n‐type). The decent ZT is mainly attributed to the intrinsically low thermal conductivity due to the high anharmonicity of the chemical bonds like those in p‐type SnSe. By alloying with 10 at% SnS, even lower thermal conductivity and an enhanced Seebeck coefficient were achieved, leading to an increased ZT of ≈1.0 at about 773 K measured also along the hot pressing direction. 相似文献
47.
48.
Benjamin Kupfer Koushik Majhi David A. Keller Yaniv Bouhadana Sven Rühle Hannah Noa Barad Assaf Y. Anderson Arie Zaban 《Liver Transplantation》2015,5(1)
Co3O4 is investigated as a light absorber for all‐oxide thin‐film photovoltaic cells because of its nearly ideal optical bandgap of around 1.5 eV. Thin film TiO2/Co3O4 heterojunctions are produced by spray pyrolysis of TiO2 as a window layer, followed by pulsed laser deposition of Co3O4 as a light absorbing layer. The photovoltaic performance is investigated as a function of the Co3O4 deposition temperature and a direct correlation is found. The deposition temperature seems to affect both the crystallinity and the morphology of the absorber, which affects device performance. A maximum power of 22.7 μW cm?2 is obtained at the highest deposition temperature (600 °C) with an open circuit photovoltage of 430 mV and a short circuit photocurrent density of 0.2 mA cm?2. Performing deposition at 600 °C instead of room temperature improves power by an order of magnitude and reduces the tail states (Urbach edge energy). These phenomena can be explained by larger grains that grows at high temperature, as opposed to many nucleation events that occur at lower temperature. 相似文献
49.
High Performance Flexible Supercapacitor Electrodes Composed of Ultralarge Graphene Sheets and Vanadium Dioxide 下载免费PDF全文
Little is known regarding the effect of the graphene lateral size on the electrochemical performance of hybrid graphene electrode. This work examines the electrochemical performance of a flexible hybrid supercapacitor electrode composed of ultralarge graphene oxide (UGO; mean lateral size of 47 ± 22 μm) and vanadium dioxide (VO2) nanobelts, referring to a reference electrode composed of small scale graphene oxide (SGO; mean lateral size of 0.8 ± 0.5 μm) and VO2.Thermal treatment converts UGO/VO2 and SGO/VO2 to URGO/VO2 (denoted VURGO) and SRGO/VO2 (denoted VSRGO) electrodes, respectively. The sheet resistance of the VURGO film (0.57 ± 0.03 kΩ sq.–1) was two orders of magnitude lower than that of the VSRGO (55.74 ± 9.35 kΩ sq.–1). The VURGO hybrid electrode showed a specific capacitance of 769 F g?1, which was significantly better than the corresponding values for the VSRGO electrode (385 F/g). These results support the notion that the use of ultralarge graphene sheets (≈22 500 μm2) lowers the intersheet resistance due to the presence of fewer intersheet tunneling barriers. This article highlights the potential utility of URGO (as a conductive support) in hybrid electrode containing VO2 nanobelts for high performance flexible hybrid supercapacitor. 相似文献
50.
Light‐Harvesting Materials: New Light‐Harvesting Materials Using Accurate and Efficient Bandgap Calculations (Adv. Energy Mater. 2/2015) 下载免费PDF全文