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21.
4月广州,春暖花开。先后召开的广州国际玩具及礼品展和广州春交会,让花城沸腾了。在这盛会上,一位年仅29岁的浙江商人和他的300多款精美的木制玩具格外引人注目,订单接踵而至。 相似文献
22.
Armlets and balanced multiwavelets: flipping filter construction 总被引:3,自引:0,他引:3
Jian-ao Lian 《Signal Processing, IEEE Transactions on》2005,53(5):1754-1767
In the scalar-valued setting, it is well-known that the two-scale sequences {q/sub k/} of Daubechies orthogonal wavelets can be given explicitly by the two-scale sequences {p/sub k/} of their corresponding orthogonal scaling functions, such as q/sub k/=(-1)/sup k/p/sub 1-k/. However, due to the noncommutativity of matrix multiplication, there is little such development in the multiwavelet literature to express the two-scale matrix sequence {Q/sub k/} of an orthogonal multiwavelet in terms of the two-scale matrix sequence {P/sub k/} of its corresponding scaling function vector. This paper, in part, is devoted to this study for the setting of orthogonal multiwavelets of dimension r=2. In particular, the two lowpass filters are flipping filters, whereas the two highpass filters are linear phase. These results will be applied to constructing both a family of the most recently introduced notion of armlet of order n and a family of n-balanced orthogonal multiwavelets. 相似文献
23.
本文对八种新型功能晶体Li2B4O7、Bi12TiO20、Bi12GeO20、Bi12GeO20、Bi4Ge3O12、Sr1-xBaxNb2O6(x=0.33,0.48)、LiTaO3等在130~973K范围内的比热行为及其与相变、组分之间的关系进行了实验研究,给出了比热的多项式拟合方程,并与用纽曼-卡普定律及用Wikelmann经验方程的比热计算值作了对比,为晶体比热的估算提供了依据和方法。 相似文献
24.
S Modi DE Gilham MJ Sutcliffe LY Lian WU Primrose CR Wolf GC Roberts 《Canadian Metallurgical Quarterly》1997,36(15):4461-4470
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin that produces Parkinsonism symptoms in man, has been examined as a substrate of recombinant human cytochrome P450 2D6. When cumene hydroperoxide is used as an oxygen and electron donor, a single product is formed, identified as 4-phenyl-1,2,3,6-tetrahydropyridine. The K(m) for formation of this product (130 microM) is in agreement with the dissociation constants for MPTP binding to the enzyme determined by optical and nuclear magnetic resonance (NMR) spectroscopy. When the reaction is carried out with nicotinamide adenine dinucleotide phosphate (reduced) (NADPH) and recombinant human NADPH-cytochrome P450 reductase, a second product, identified as 1-methyl-4-(4'-hydroxyphenyl)-1,2,3,6-tetrahydropyridine, is formed in addition to 4-phenyl-1,2,3,6-tetrahydropyridine. The K(m) values for formation of these two products are 19 microM and 120 microM, respectively. Paramagnetic relaxation experiments have been used to measure distances between the protons of bound MPTP and the heme iron, and these have been used to construct models for the position and orientation of MPTP in the active site. For the cytochrome alone, a single mode of binding was observed, with the N-methyl close to the heme iron in a position appropriate for the observed N-demethylation reaction. In the presence of the reductase, the data were not consistent with a single mode of binding but could be explained by the existence of two alternative orientations of MPTP in the active site. One of these, characterized by a dissociation constant of 150 microM, is essentially identical to that observed in the absence of the reductase. In the second, which has a K(d) of 25 microM, the MPTP is oriented so that the aromatic ring is close to the heme iron, in a position appropriate for p-hydroxylation leading to the formation of the product seen only in the presence of the reductase. In the case of codeine, another substrate for cytochrome P450 2D6, the addition of reductase had no effect on the nature of the product formed, the dissociation constant, or the orientation in the binding site. These observations show that NADPH-cytochrome P450 reductase has an allosteric effect on the active site of cytochrome P450 2D6 that affects the binding of some substrates but not others. 相似文献
25.
高速冷带轧机垂直自激振动稳定性分析的数值计算方法 总被引:5,自引:0,他引:5
本文在充分考虑轧机垂直振动过程中辊缝非线性的基础上,利用轧制理论方程和机械振动理论中的能量判据,给出了更精确的分析高速冷轧机垂直自激振动稳定性的数值计算方法。 相似文献
26.
对几种增黑剂进行了筛选实验研究,选用了两种增黑剂组合使用,提高了遮盖力,使医用X光胶片涂布银量由原业的9g/m2降到了6.8g/m2,与美国医用X光胶片涂布银量(6.7g/m2)相当,照相性能不低于国产医用X光胶片。 相似文献
27.
This work reports the fabrication and the characterization of a new composite consisting of multiwalled carbon nanotubes (CNTs) and conducting titanium nitride (TiN) with a higher specific surface area ( S BET ), enhanced electrical conductivity (σ), and specific capacitance. With increasing CNT content, the electrical conductivity and electrochemical performance of the CNT–TiN composites gradually increase. In the presence of 5 wt% (12.0 vol%) CNTs, the electrical conductivity and the weight-specific capacitance of CNT–TiN composite are increased by 3.6 times and 54.8% compared with pure TiN, respectively. 相似文献
28.
汽车空调冷凝器腐蚀试验的表征与评价 总被引:3,自引:0,他引:3
介绍了汽车空调冷凝器的腐蚀试验程度及方法,对试验后的冷凝器进行了密封性检查,并用光学显微镜和扫描电镜检测和分析了材料的显微结构,焊接质量,腐蚀性质及其腐蚀深度等。通过对冷凝器的宏微观检查与表征,评价了冷凝器质量的优劣,提出了改进措施与建议。 相似文献
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