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91.
Facile Generation of L10‐FePt Nanodot Arrays from a Nanopatterned Metallopolymer Blend of Iron and Platinum Homopolymers 下载免费PDF全文
Qingchen Dong Guijun Li Cheuk‐Lam Ho Chi‐Wah Leung Philip Wing‐Tat Pong Ian Manners Wai‐Yeung Wong 《Advanced functional materials》2014,24(6):857-862
Hard ferromagnetic (L10 phase) FePt alloy nanoparticles (NPs) with extremely high magnetocrystalline anisotropy are considered to be one of the most promising candidates for the next generation of ultrahigh‐density data storage system. The question of how to generate ordered patterns of L10‐FePt NPs and how to transform the technology for practical applications represents a key current challenge. Here the direct synthesis of L10 phase FePt NPs by pyrolysis of Fe‐containing and Pt‐containing metallopolymer blend without post‐annealing treatment is reported. Rapid single‐step fabrication of large‐area nanodot arrays (periodicity of 500 nm) of L10‐ordered FePt NPs can also be achieved by employing the metallopolymer blend, which possesses excellent solubility in most organic solvents and good solution processability, as the precursor through nanoimprint lithography (NIL). Magnetic force microscopy (MFM) imaging of the nanodot pattern indicates that the patterned L10 phase FePt NPs are capable of exhibiting decent magnetic response, which suggests a great potential to be utilized directly in the fabrication of bit patterned media (BPM) for the next generation of magnetic recording technology. 相似文献
92.
瞬态包络分析算法是一种快速有效的仿真算法,被广泛应用于RF电路仿真中,文章主要研究了基于打靶法的瞬态包络分析算法-采样包络算法,并给出了该算法的具体流程和计算机实现结果。 相似文献
93.
Many studies showed an increased occurrence of primary hyperparathyroidism during lithium therapy. We studied 53 patients receiving lithium therapy prospectively for 2 yr. Serum PTH levels were unequivocally elevated. The baseline PTH level was 2.8 +/- 1.2 pmol/L and increased progressively to 3.9 +/- 1.5 pmol/L after 2 yr (P < 0.0005). There was no change in serum calcium, alkaline phosphatase, inorganic phosphate concentrations or tubular reabsorption of phosphate in relation to glomerular filtration rate. Fasting urinary reabsorption of calcium increased significantly (P < 0.0005), which was concordant with the PTH change. Fasting and 24-h urinary excretion of calcium decreased significantly (P < 0.0005), suggesting reduced, rather than enhanced, bone resorption as in primary hyperparathyroidism. This may be the main mechanism in maintaining normocalcemia, despite PTH elevation, during lithium therapy. 相似文献
94.
Obtaining high-quality radiographs of the proximal aspect of equine limbs is difficult because of the large muscles in these regions. The use of scintigraphy may provide further information. Abnormal bone scan findings of the ischial tuberosity or the third trochanter were found in 29 adult horses with obscure hind limb lameness between 1986 and 1996 at the Large Animal Clinic of the University of Bern. Each had abnormal radiopharmaceutical uptake but not all had radiographic changes. Radiopharmaceutical uptake ratios between the ischial tuberosity and the greater trochanter were calculated. The uptake ratio in a control group of 11 clinically sound horses was lower than in 11 lame horses with subjectively enhanced radiopharmaceutical uptake. 相似文献
95.
A systematic experimental and theoretical study on the crack growth behaviour of a sintered Al2O3/ZrO2 ceramic under cyclic loading is presented. It is found that in the cyclic fatigue experiments conducted on the single-edge-notched beam (SENB) geometry, for similar testing conditions, the crack growth rates are significantly faster than those under static fatigue. Al2O3/ZrO2 therefore suffers genuine mechanical fatigue. Further experiments with the compact tension (CT) geometry show that the mechanical fatigue effect arises mainly from the degradation of the bridging mechanism. A theoretical analysis based on the compliance technique and a power law relationship between the crack-wake bridging stress and the crack-face separation is developed to evaluate quantitatively the degradation of the bridging stress due to cyclic fatigue. 相似文献
96.
Wing Shing Wong 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(6):2060-2071
With recent developments in ad hoc networks and sensor networks, random-access protocol without feedback is a technique that deserves a closer look. This paper is based on Massey's model on random-access channel without feedback. A central concept of this model is the idea of protocol sequences. For these sequences, it is desirable that their cross correlation should be as low as possible and that the length of their period should not be too long, even if there is a large number of active users. Another useful feature is to be able to support multirate communication. Based on these considerations, a new family of protocol sequences is proposed in this paper. These new protocol sequences are built on the concept of prime sequences. It is shown that these sequences possess properties that make them suitable candidates for designing random access protocols for certain ad hoc or sensor networks 相似文献
97.
98.
Nylon 66 nanocomposites were prepared by melt compounding of nylon 66 with organically modified montmorillonite (MMT). The organic MMT was pre‐modified with about 14 wt% of ammonium surfactant, much lower than the 35–46 wt% in most commercial organic MMT powders. Transmission electron microscope observation indicated that the MMT layers were well exfoliated in nylon 66 matrix. Dynamic mechanical analysis confirmed the constraint effect of exfoliated MMT layers on nylon 66 chains, which benefited the increased storage modulus, increased glass transition temperature and reduced magnitude of alpha relaxation peak. The effects of organic MMT loading levels on reinforcement and fracture behaviour of the nanocomposites were evaluated using tensile and three‐point bending tests. The addition of the organic MMT clearly increased Young's modulus and tensile strength but decreased ductility and fracture toughness of nylon 66. Copyright © 2004 Society of Chemical Industry 相似文献
99.
Jiun-Haw Lee Xinyu Zhu Yi-Hsin Lin Wing Kit Choi Tien-Chun Lin Sheng-Chih Hsu Hoang-Yan Lin Shin-Tson Wu 公伟刚 朱正龙 周立 《现代显示》2006,(10):30-36
一种高环境对比度(A-CR)和大开口率的显示器已经从理论上证明,并通过把一个正常显黑反射型显示器(NB-RLCD)和一个有机电致发光器件(OLED)堆垛的实验加以证明。这种前后双置(以下称为tandem型)的器件组合可以分别在明亮或昏暗的环境下切换NB-RLCD模式或OLED模式。RLCD的正常显黑特性也可以提升OLED模式工作时的A-CR性能。为了在RLCD模式下获得更好的图像品质,一个复杂并且具有传输功能的结构被用于消除镜面反射和提高可视角至CR﹥2:1超过55°的锥面可视角度。另外,这样的结构也可以提高OLED49.4%的表面量子效率。在我们的实验里,忽略环境亮度因素并使A-CR保持在100:1以上。 相似文献
100.
Leon Wing Seng Taylor Desmond P. 《International Journal of Wireless Information Networks》2002,9(4):275-286
A simple DPSK receiver for the linearly frequency-selective fading channel is presented. The channel is modelled as an f-power series truncated to the first two terms [1], [2]. Two specifically designed time invariant filters are used to remove the channel-induced ISI and separate the two implicit diversity branches. The received samples from each filter are then differentially decoded and linearly combined. Analytical and simulation results for binary DPSK demonstrate that this receiver shows significant improvement over the conventional receiver, which uses matched filtering and a product demodulator. 相似文献