Materials Literature
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采用超声分散的方法,以少量八甲基环四硅氧烷(D 4 )对硅溶胶粒子进行表面接枝改性。然后在改性硅溶胶存在下,以十二烷基苯磺酸(DBSA)为乳化剂兼催化剂进行D 4 的微滴乳液聚合,得到聚硅氧烷(PDMS)/二氧化硅(SiO 2 )纳米复合乳液。采用FTIR、TGA、纳米粒度仪、TEM和拉力机分别对样品进行了表征。结果表明:采用超声分散的方法,能够有效地实现硅溶胶粒子的表面改性。通过微滴乳液聚合得到的复合乳胶粒是聚合物包覆二氧化硅粒子的核壳结构形态。SiO 2 的引入提高了有机硅复合膜力学性能,增强了热稳定性。
A utilizacao de materiais plasticos de fontes petroliferas geram incomodos ambientais. Nesse contexto, pesquisas sobre materiais biodegradaveis tem sido realizadas. Filmes biodegradaveis de amido de mandioca e Poli(Butileno Adipato coTereftalato), plastificados com glicerol, foram produzidos por extrusao-sopro em duas…
Multiscale models play a key role in capturing the inelastic response of woven carbon fiber reinforced ceramic matrix composites. Due to the mismatch in the thermal properties between the constituents of plain weave carbon fiber/silicon carbide composites, microcracks are present in the as-produced composite. Capturin…
First-principles modeling of the grain boundary Σ5 bcc iron are carried out by WIEN2k code. Optimal parameters and the grain boundary formation energy for the two tilt angles are calculated.
Os plasticos sao amplamente utilizados na producao de embalagens de produtos alimenticios, utensilios domesticos, higiene e limpeza, cosmeticos, farmaceuticos e industriais. No entanto, plasticos convencionais sao responsaveis por gerar uma grande quantidade de residuos que sao depositados ao ambiente e requerem um lo…
AbstractProtein extraction from bone is extremely difficult task because the bone tissue is hard to dissolve. Special care must be taken during extraction to prevent protein degradation and/or unfolding. Boiling is a traditional method for extracting protein from bones, but heat denaturation during this process destro…
Alumina matrix ceramic composites were fabricated by pressureless sintering. The effect of temperature and holding time, two of the most important pressureless sintering parameters, on the microstructures and grain growth of undoped and diopside doped alumina was researched. Experiments were performed at the temperatu…
Three related topics are addressed in this article: (i) X-ray spectroscopy (XAS) studies of remote plasma deposited (RPD) nc-SiO 2 and nc-GeO 2 emphasizing (a) band-edge states and (b) pre-existing bonding defects; (ii) interpretation of X-ray absorption and photoemission spectra based on many electron theory, and in…
We report the magnetotransport and $dc$ magnetic susceptibility of the polycrystalline samples of Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$, to examine the effect of magnetic field on the superconducting phase of the metallic CuO double chain. The resistive critical magnetic field is estimated to be about 21 T at low te…
Defect states in the forbidden band-gap below the conduction band edge are active as electron traps in nano-grain high-) transition metal (TM) oxides with thickness >0.3 nm, e.g., ZrO 2 and HfO 2 . These oxides have received considerable attention as gate-dielectrics in complementary metal oxide semiconductor (CMOS) d…
Crystals of transition metal compounds with perovskite and spinel structures are characterized by several competing electron interactions responsible for different structural and magnetic orderings. The shape of the acoustic anomaly temperature dependences allows to distinguish between them and to estimate the differe…
Density functional theory calculations were used to examine the effects of intrinsic surface defects of Cu(111) on the adsorption of methylthiol (CH3SH). The examination covers both the initial non-dissociative adsorption and the subsequent dissociation reaction pathways to form intermediate and final reaction product…
The system under consideration is a molecule or an impurity center in a crystal with a two-fold quasi-degenerate electronic state (pseudo Jahn-Teller system) in strong interaction with one main mode and in weak interaction with continuum of secondary modes of phonons. This system exhibits strong non-adiabatic coupling…
In many systems, nucleation of a stable solid may occur in the presence of other (often more than one) metastable phases. These may be polymorphic solids or even liquid phases. In such cases, nucleation of the solid phase from the melt may be facilitated by the metastable phase because the latter can "wet" the interfa…
Abstract C10H26I2N4NiO2, monoclinic, P21/c (no. 14), a = 7.6587(4) Å, b = 17.4436(8) Å, c = 15.0273(7) Å, β = 98.770(1)°, V = 1984.1 Å3, Z = 4, Rgt(F) = 0.0406, wRref(F) = 0.0435, T = 296 K.
Copper oxides are the only materials that show transition temperatures, Tc, above the boiling point of liquid nitrogen, with a maximum Tmc of 162 K under pressure. Their structure is layered, with one to several CuO2 planes, and upon hole doping, their transition temperature follows a dome-shaped curve with a maximum…
Two new Mn(II) coordination polymers, {[Mn(5-CH3-ip)(bib)]·2H2O}n (1) and [Mn (5-CH3- ip)(bib)0.5]n (2) (5-CH3-ip = 5-Methyl-1,3-benzenedicarboxylic acid bib = 1,4-bis(imidazol-1-yl) benzene), have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. Complex 1 shows a 2D layer structure…
利用扫描电子显微镜(SEM)和能谱(EDS)测试了电镀Ni-Sn-P合金镀层在人工海水中腐蚀前后表面形貌和合金成分的变化,结合X射线光电子能谱(XPS)对腐蚀后合金表面的组成进行了分析,并在此基础上探讨了Ni-Sn-P合金镀层在人工海水中的腐蚀机理。研究结果表明:电镀Ni-Sn-P合金在人工海水中耐蚀性优于Ni-P合金,由于人工海水中的氯离子的穿透效应而出现的局部腐蚀孔数较Ni-P合金大幅减少,腐蚀后Ni-Sn-P合金表面形成由SnO 2 、SnCl 4 、Ni 3 (PO 4 ) 2 、NiO和Ni(OH) 2 组成的膜层,对合金耐蚀性的提高起到重要作用。
We discuss emergence of superconductivity in a two-dimensional eg-electron system coupled with Jahn-Teller phonons in the framework of the Migdal-Eliashberg theory. Here we focus on the dependence of superconducting transition temperature Tc on the Fermi-surface structure controlled by the Slater-Koster integrals of e…
ÖZET: Bu araştırma, farklı ana materyaller üzerinde oluşmuş toprakların pedolojik özellikleri ile kıvam limitleri ve şişme-büzülme karakteristiklerinin toprak profil derinliğindeki değişimini incelemek amacıyla yürütülmüştür. Çalışma, lakustrin kil, bazalt ve kireçli alüviyal ana materyal üzerinde oluşmuş üç profilin…