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101.
《材料科学技术学报》2019,35(9):1977-1981
Titanium oxide (TiO2), with excellent cycling stability and low volume expansion, is a promising anode material for lithium-ion battery (LIB), which suffers from low electrical conductivity and poor rate capability. Combining nano-sized TiO2 with conductive materials is proved an efficient method to improve its electrochemical properties. Here, rutile TiO2/carbon nanosheet was obtained by calcinating MAX (Ti3AlC2) and Na2CO3 together and water-bathing with HCl. The lamellar carbon atoms in MAX are converted to 2D carbon nanosheets with urchin-like rutile TiO2 anchored on. The unique architecture can offer plentiful active sites, shorten the ion diffusion distance and improve the conductivity. The composite exhibits a high reversible capacity of 247 mA h g−1, excellent rate performance (38 mA h g−1 at 50 C) and stable cycling performance (0.014% decay per cycle during 2000 cycles) for lithium storage. 相似文献
102.
《材料科学技术学报》2019,35(8):1797-1802
A new insight into the promotion action of Co2+ on both particle and metal deposition in Ni-diamond composite electrodeposition system was analyzed according to electrochemical measurements. The results showed that the addition of Co2+ made particles content in deposits increased remarkably. The change of particles content in deposits was related inversely to the change of cathodic zero potential with the increase of the concentration of cobalt sulfate. Zero charge potential of cathode was shifted to much more negative region. The negative shift of the zero potential, combining with positive shift of the zeta potential, increased the electrostatic force between the particle-adsorbed metallic cations and the cathode. It not only benefits to the transportation of particles in solution towards cathode, but also shortens their residence time on cathodic surface. Meanwhile, entry of particles is also promoted. For metals deposition, reduction resistance of metallic cations rises greatly and deposition current at cathodic potentiodynamic polarization decreases after cobalt sulfate has been added into electrolyte. These factors are favorable for increasing particles content in deposits. In addition, physical model of diamond particles deposition state before and after the addition of Co2+ has been discussed. 相似文献
103.
Chiou-Yng Lee Author Vitae Pramod Kumar Meher Author Vitae 《Computers & Electrical Engineering》2010,36(5):955-968
Hardware implementation of multiplication in finite field GF(2m) based on sparse polynomials is found to be advantageous in terms of space-complexity as well as the time-complexity. In this paper, we present a new permutation method to construct the irreducible like-trinomials of the form (x + 1)m + (x + 1)n + 1 for the implementation of efficient bit-parallel multipliers. For implementing the multiplications based on such polynomials, we have defined a like-polynomial basis (LPB) as an alternative to the original polynomial basis of GF(2m). We have shown further that the modular arithmetic for the binary field based on like-trinomials is equivalent to the arithmetic for the field based on trinomials. In order to design multipliers for composite fields, we have found another permutation polynomial to convert irreducible polynomials into like-trinomials of the forms (x2 + x + 1)m + (x2 + x + 1)n + 1, (x2 + x)m + (x2 + x)n + 1 and (x4 + x + 1)m + (x4 + x + 1)n + 1. The proposed bit-parallel multiplier over GF(24m) is found to offer a saving of about 33% multiplications and 42.8% additions over the corresponding existing architectures. 相似文献
104.
Emilia L. ApostolovaAuthor Vitae Anelia G. DobrikovaAuthor VitaeGeorgi D. RashkovAuthor Vitae Kolyo G. DankovAuthor VitaeRadka S. VladkovaAuthor Vitae Amarendra N. MisraAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):140-146
Freshly prepared pea thylakoid membranes were immobilized in bovine serum albumin-glutaraldehyde cross-linked matrix (BSA-GA matrix) and their stability under long term storage was analyzed by Pulse-Amplitude-Modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution measured by oxygen rate electrode. The thylakoid membranes stored at 4 °C showed prolonged stability in BSA-GA matrix and additional adsorption on nitrocellulose membrane filters gave them more stability. The sensitivity of the parameters of the oxygen evolution of thylakoid membranes to atrazine increased with immobilization. The half-inhibition time for oxygen evolution and quantum efficiency of photosynthesis could be prolonged to more than 15 days. These results suggest that the immobilized thylakoid membranes in BSA-GA matrix can be used as biological receptor in biosensors for a long period of time (up to 25 days) applying the proposed new method for atrazine detection by using polarographic oxygen rate electrode. This method is more sensitive, faster and easier to use than other methods for detection of herbicides based on determination of the photochemical activity of photosystem II. 相似文献
105.
Assyr Abdulle Achim Nonnenmacher 《Computer Methods in Applied Mechanics and Engineering》2009,198(37-40):2839-2859
We describe a multiscale finite element (FE) solver for elliptic or parabolic problems with highly oscillating coefficients. Based on recent developments of the so-called heterogeneous multiscale method (HMM), the algorithm relies on coupled macro- and microsolvers. The framework of the HMM allows to design a code whose structure follows the classical finite elements implementation at the macro level. To account for the fine scales of the problem, elementwise numerical integration is replaced by micro FE methods on sampling domains. We discuss a short and flexible FE implementation of the multiscale algorithm, which can accommodate simplicial or quadrilateral FE and various coupling conditions for the constrained micro simulations. Extensive numerical examples including three dimensional and time dependent problems are presented illustrating the efficiency and the versatility of the computational strategy. 相似文献
106.
特征降维是文本分类过程中的一个重要环节。在现有特征选择方法的基础上,综合考虑特征词在正类和负类中的分布性质,综合四种衡量特征类别区分能力的指标,提出了一个新的特征选择方法,即综合比率(CR)方法。实验采用K-最近邻分类算法(KNN)来考查CR方法的有效性,实验结果表明该方法能够取得比现有特征选择方法更优的降维效果。 相似文献
107.
张三元 《中国图象图形学报》2001,6(6):573-576
曲面上的曲线造型是计算机图形领域的一个新的研究热点,而且它们在纤维织物编织,三维服装裁剪以及复合材料的纤维缠绕轨迹设计等领域有十分广泛的应用,为了解决圆环面上纤维轨迹的计算机辅助设计问题,研究了圆环面上测地线的解析解以及拟测地线数值求解的具体算法并给出了其表达式,测地线是曲面上两点之间最短距离的曲线段,在一般曲面上没有解析解,但是在圆环面上却可求出其精确的解析解,但在曲面的边沿部分,测地线因不能实现自然的折返过渡,于是拟测地线就被引进到曲面上的曲线造型设计之中,在拟测地线分析研究基础上,给出了圆环面上拟测地线的方程及数值解法,通过其在一个实例中的应用结果证明,该方法可获得织物的纺织条纹以及缠绕物体的纤维轨迹。 相似文献
108.
Ca2+和Pb2+与双层类脂膜相互作用的研究 总被引:2,自引:0,他引:2
用电化学方法研究了卵磷脂和氧化胆固醇构成的双层类脂膜与 Ca~(2+)和 Pb~(2+)的相互作用。结果发现:双层类脂膜与含 Ca~(2+)或 Pb~(2+)的溶液接触15分钟后,产生较稳定的膜电位信号并与溶液中 Ca~(2+),Pb~(2+)浓度相关。其作用机制主要是源于静电作用与合作效应,同时,对三种不同存在状态的双层类脂膜的通透性进行了验证,对某些干扰离子和 pH 值的影响进行了研究。 相似文献
109.
Yasmin Srivastava Christopher Rhodes Manuel Marquez Todd Thorsen 《Microfluidics and nanofluidics》2008,5(4):455-458
Hollow poly (vinylpyrrolidone) (PVP) + TiO2 and polypyrrole (core)/PVP (sheath) nanofibers were successfully electrospun using hydrodynamic fluid focusing. Utilizing
a two-dimensional fluid focusing technique previously applied to aqueous solutions, intersecting microchannels cast in (poly)dimethylsiloxane
were utilized to dynamically center core fluids in immiscible sheath fluids prior to electrospinning at the channel outlet.
Advantages of using microfluidic channel networks for the electrospinning of composite nanofibers include spatiotemporal control
over input reagents, ease of fabrication and the ability to focus the core stream into sheath layer without the need of complex
co-annular nozzles. 相似文献
110.
Design of laminated composite structures for optimum fiber direction and layer thickness,using optimality criteria 总被引:1,自引:1,他引:0
In this study, two optimality criteria are presented for optimum design of composite laminates using finite element method.
Thickness of the layers and fiber orientation angles in each finite element are considered as the design variables. It will
be shown that the optimum design of composite laminates with varying fiber orientations and layers thicknesses may be found
by using these optimality criteria in an efficient way, without performing the sensitivity analysis. 相似文献