首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到15条相似文献,搜索用时 0 毫秒
1.
以高铝矾土、硅灰为原料, 玉米淀粉为造孔剂制备高气孔率莫来石, 通过XRD、SEM等对产物物相、形貌进行表征, 研究淀粉含量对显气孔率、体积密度和抗折强度的影响, 及不同显气孔率的莫来石随温度变化的导热系数, 建立体积密度、抗折强度与气孔率关系模型及非线性导热模型。结果表明: 体积密度、抗折强度随气孔率增加而减小, 并符合指数函数关系。导热系数随温度的升高而增大, 实测值与非线性导热模型计算值吻合较好, 非线性导热模型能够准确地反映高气孔率莫来石导热系数与温度、气孔率、平均孔径和热辐射等之间的关系。  相似文献   

2.
3.
4.
5.
Fiber‐shaped supercapacitors (FSCs) are promising energy storage solutions for powering miniaturized or wearable electronics. However, the scalable fabrication of fiber electrodes with high electrical conductivity and excellent energy storage performance for use in FSCs remains a challenge. Here, an easily scalable one‐step wet‐spinning approach is reported to fabricate highly conductive fibers using hybrid formulations of Ti3C2Tx MXene nanosheets and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate. This approach produces fibers with a record conductivity of ≈1489 S cm?1, which is about five times higher than other reported Ti3C2Tx MXene‐based fibers (up to ≈290 S cm?1). The hybrid fiber at ≈70 wt% MXene shows a high volumetric capacitance (≈614.5 F cm?3 at 5 mV s?1) and an excellent rate performance (≈375.2 F cm?3 at 1000 mV s?1). When assembled into a free‐standing FSC, the energy and power densities of the device reach ≈7.13 Wh cm?3 and ≈8249 mW cm?3, respectively. The excellent strength and flexibility of the hybrid fibers allow them to be wrapped on a silicone elastomer fiber to achieve an elastic FSC with 96% capacitance retention when cyclically stretched to 100% strain. This work demonstrates the potential of MXene‐based fiber electrodes and their scalable production for fiber‐based energy storage applications.  相似文献   

6.
7.
以玻璃纤维膨体纱织物为基材,以环氧树脂E44为粘着剂,650低分子量聚酰胺为固化剂,以价格低廉、密度较小的滑石粉为吸波材料,制备了滑石粉涂层复合材料。重点探讨了滑石粉含量及涂层厚度对介电常数和电导率的影响。结果表明制备的滑石粉涂层复合材料具备良好的介电性能。在研究的频率范围内,滑石粉的含量、涂层厚度对复合材料的介电常数实部和虚部、损耗角正切值、电导率的实部和虚部影响较大。  相似文献   

8.
Polycrystalline samples with nominal compositions Pr0.5Sr0.5Mn0.5Cu0.5O3 and Pr0.5Sr0.5Mn0.5 Ru0.5O3 were synthesized and their magnetical and transport properties were investigated. It was shown that Pr0.5Sr0.5Mn0.5Cu0.5O3 is an insulator with an AFM state accompanied by weak FM at low temperatures. The transport mechanism in this highly doped with Cu manganite can be explained by a conventional thermal activation. The Pr0.5Sr0.5Mn0.5Ru0.5O3 material has a PM-FM transition beginning at T C 325 K and a FM-AFM one—at about 160 K. The low magnetization values and temperature and field dependencies of the magnetization suggest a phase separation of anomalous FM state and AFM state below the FM-AFM transition. The carrier transport in the highly doped with Ru manganites can be described by a small polaron hopping model.  相似文献   

9.
We present the results of our theoretical analysis of magnetic, electric, and transport properties of domain walls in ferromagnets. The results were obtained within the semiclassical approximation and are valid for smooth domain walls. Taking into account Coulomb interaction between electrons, we calculated spin and charge accumulation at the wall. Local conductivity due to scattering from impurities located in the region of the domain wall was also calculated.  相似文献   

10.
We have shown that properties of lightly doped quasi-layered cuprates can be described on the basis of topological excitation known as skyrmions both thermally excited and induced by quasi-localized electronic holes. We have calculated the average skyrmion radius r 0 and nuclear spin relaxation rate 1/T 1 as a function of temperature and hole concentration. The results are in qualitative agreement with experiments.  相似文献   

11.
Once injected into a living organism, cells diffuse or migrate around the initial injection point and become impossible to be visualized and tracked in vivo. The present work concerns the development of a new technique for therapeutic cell labeling and subsequent in vivo visualization and magnetic retention. It is hypothesized and subsequently demonstrated that nanohybrids made of persistent luminescence nanoparticles and ultrasmall superparamagnetic iron oxide nanoparticles incorporated into a silica matrix can be used as an effective nanoplatform to label therapeutic cells in a nontoxic way in order to dynamically track them in real‐time in vitro and in living mice. As a proof‐of‐concept, it is shown that once injected, these labeled cells can be visualized and attracted in vivo using a magnet. This first step suggests that these nanohybrids represent efficient multifunctional nanoprobes for further imaging guided cell therapies development.  相似文献   

12.
Flexible aqueous zinc batteries are promising candidates as safe power sources for fast-growing portable and wearable electronics. However, the low working voltage, poor rate capability, and cycling stability have greatly restricted their development and applications. Here, a new family of flexible bimetallic phosphide/carbon nanotube hybrid fiber electrodes with unique macroscopic microcrack structure and microscopic porous nanoflower structure is reported. The hierarchical microcrack structure not only facilitates the penetration of electrolyte for effective exposure of active sites, but also can serve as buffers to relieve the stress concentrations of the fiber electrode under deformations, enabling impressive electrochemical performance and mechanical flexibility. Particularly, the fabricated flexible aqueous zinc batteries demonstrate high working voltage plateau and specific capacity (≈1.7 V, 258.9 mAh g−1 at 2 A g−1), ultrahigh rate capability (135.8 mAh g−1 at 50 A g−1, fully charged in only 9.8 s) and impressive power density of 79 000 W kg−1. Moreover, the flexible batteries show ultralong cycling life with 74.6% capacity retention after 20 000 cycles. The fiber batteries are also highly flexible and can be easily knitted into soft electronic textiles to power a smartphone, which are particularly promising for the next-generation of flexible and wearable electronics.  相似文献   

13.
Engineering of the optical, electronic, and magnetic properties of hexagonal boron nitride (h‐BN) nanomaterials via oxygen doping and functionalization has been envisaged in theory. However, it is still unclear as to what extent these properties can be altered using such methodology because of the lack of significant experimental progress and systematic theoretical investigations. Therefore, here, comprehensive theoretical predictions verified by solid experimental confirmations are provided, which unambiguously answer this long‐standing question. Narrowing of the optical bandgap in h‐BN nanosheets (from ≈5.5 eV down to 2.1 eV) and the appearance of paramagnetism and photoluminescence (of both Stokes and anti‐Stokes types) in them after oxygen doping and functionalization are discussed. These results are highly valuable for further advances in semiconducting nanoscale electronics, optoelectronics, and spintronics.  相似文献   

14.
Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.  相似文献   

15.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号