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871.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):239-257
Optical materials, such as ophthalmic lens, are thermosetting resins, which require crosslinking agents. An optical resin, having a high refractive index, is usually produced by radical copolymerization in which high index crosslinking monomers are significantly important. We provide here the resins prepared by radical polymerization of novel bifunctional thiomethacrylates as high index crosslinkers. 相似文献
872.
利用CRn系数等统计学方法测算2003—2012年全国地级以上城市经济实力差异变化情况,选取2003,2008,2012年3个时间断面的数据对全国283个地级及其以上城市经济实力进行了评价分析.结果表明:该方法能较好地反映中国地级以上城市经济实力状况;城市经济实力呈快速增长趋势,经济实力相对差异逐渐缩小,绝对差异进一步扩大;经济实力差异东中西地带性特征明显,经济实力比重东降西升,东中部差异逐渐减小,但中西部差异先扩大后缩小,整体差异呈减小趋势;城市经济实力等级特征显著,城市经济实力两极分化依然严重,强实力城市和弱实力城市符合"二八定律",20%的强实力城市占全国经济实力的80%;从经济实力排名变化来看,全国大部分城市经济实力排名逐渐相对稳定,排名变化比较剧烈的城市主要位于中西部几大经济发展迅速的城市群及其周围地区. 相似文献
873.
An extended π-electronic conjugation system of 1,1′-bis(diacetylene-group) connected ferrocene-thiophene derivative has been synthesized, with our integrated reaction between the corresponding TMS-protected acetylenes in one-pot. Its electronic properties have been examined, suggesting a cooperatively functional behavior of the diacetylene-group connected constituents. 相似文献
874.
875.
The neglected pillar of material computation 总被引:1,自引:0,他引:1
Susan Stepney 《Physica D: Nonlinear Phenomena》2008,237(9):1157-1164
Many novel forms of computational material have been suggested, from using slime moulds to solve graph searching problems, to using packaging foam to solve differential equations. I argue that attempting to force such novel approaches into the conventional Universal Turing computational framework will provide neither insights into theoretical questions of computation, nor more powerful computational machines. Instead, we should be investigating matter from the perspective of its natural computational capabilities. I also argue that we should investigate nonbiological substrates, since these are less complex in that they have not been tuned by evolution to have their particular properties. Only then we will understand both aspects of computation (logical and physical) required to understand the computation occurring in biological systems. 相似文献
876.
C. Venkataraju G. Sathishkumar K. Sivakumar 《Journal of magnetism and magnetic materials》2010,322(2):230-233
Nano particles of Mn(0.5–x)NixZn0.5Fe2O4 (x=0.0, 0.1, 0.2, 0.3) have been synthesized by chemical co-precipitation method. The lattice constant and distribution of cation in the tetrahedral and octahedral sites have been deduced through X-ray diffraction (XRD) data analysis. The lattice constant (Å) for all Mn/Ni concentration is found to be less than that for the corresponding bulk values. X-ray intensity calculations indicate that there is deviation in the normal cation distribution. Magnetization decreases with increasing Ni concentration except for x=0.3, where it shows increasing trend. This is due to migration of Fe3+ ions from B-site to A-site, which reduces the B–B coupling and there by the spin canting in the B sublattice. The Curie temperature was found to decrease with increase in nickel concentration except for x=0.3, where it shows a rise. Coercivity is very low and is found to be inversely proportional to the grain size. 相似文献
877.
激光雷达GLAS与ETM联合反演森林地上生物量研究 总被引:2,自引:0,他引:2
在实现大脚印激光雷达GLAS森林冠顶高度反演算法基础上, 建立了复杂地形条件下森林地上生物量神经网络反演模型, 制作了研究区森林地上生物量分布图。总体上, 激光雷达GLAS森林冠顶高度和地上生物量估算精度较高。森林冠顶高度针叶林精度最好(R2=0.692); 阔叶林次之(R2=0.5062); 地上生物量反演结 果与实测结果十分接近, 在空间分布上与土地覆盖分布特征非常一致。 相似文献
878.
用200KeV质子,400KeV和8MeV电子分别辐照YBaCuO高Tc超导材料,其影响是不同的.质子注入使零电阻温度从86.7K提高到89.8K,而剂量为2.25×1014电子/cm2的8MeV的电子辐照却使超导体的零电阴温度下降3K左右.当电子辐照剂量为1.35×1015e/cm2时,超导体变成绝缘体.用高分解电镜对400keV的电子辐照分况进行实地在线研究,发现当剂量到1.0×1026e-/cm2时,氧化物超导体中的品相出现非品化,而其原来为非品区域处处出现有序化. 相似文献
879.
Magnetic fluid-assisted finishing has been verified both theoretically and experimentally as an effective fabrication technology for optical mirrors and lenses. The purpose of this paper is to introduce a novel design of polishing tool and demonstrate the possible applications of this technology. The work includes studying the viscosity of the magnetic suspensions of micrometer-sized Carbonyl iron particles under the influence of a magnetic field. Both the cases of magnetizable suspension with and without abrasive cerium oxide particles are studied for their ensuing polishing effectiveness. Determination of material removal function is conducted using a Wyko Nat1100 interferometer. Experiments to reduce surface roughness with the proposed tool are also performed using a K9 mirror as the work-piece. Results show that the surface accuracy is improved over three times to less than 0.5 nm after two cycles of polishing. 相似文献
880.
Bin Zhang Se Hun Chung Susan Barker Duncan Craig Roger J.Narayan Jie Huang 《自然科学进展(英文版)》2021,31(2):180-191
There has been increasing interest over recent years in the application of three-dimensional(3 D) printing technologies in the biomedical field. One such method is Direct Ink Writing(DIW); this approach has the potential advantage of allowing room-temperature deposition of materials, presented as an ink, to build complex architectures. DIW offers the ability to process biomaterials containing temperature-sensitive components. Due to the fabrication principles of DIW, there are specific rheologic... 相似文献