α-Fe(Si)纳米晶对软磁合金的贡献

本文用置换固溶体结构机制，去分析ＦｅＣｕＮｂＳｉＢ纳米软磁合金中α－Ｆｅ（Ｓｉ）相表面Ｆｅ原子的合成磁矩．并用磁畴理论等物理视角去解释该类合金综合软磁物理性能优异的主原因     

Surface interactions of MoO3/ α-Fe2O3 system

α-Fe₂O₃ -supported molybdena catalysts have been prepared by heating a mixture of MoO₃ and α-Fe₂O₃. XRD, XPS, LRS, TG-DTA and Mössbauer spectroscopy were used to characterize the interactions between MoO₃ and α-Fe₂O₃. The dispersion capacity of MoO₃ on the surface of α-Fe₂O₃ determined by XRD and XPS was 0.8 mmol/100m² α-Fe₂O₃ in the samples calcined at 420 . For the sample with low MoO₃ loading, LRS and FT-IR results showed that Mo⁶⁺ ions were located in the tetrahedral vacant sites on the surface of α-Fe₂O₃, signed as Mo- . The amount of Mo-II species, formed by Mo6+ ions incorporated into the octahedral vacant sites, increased with the MoO₃ loading. Based on the assumption that the (001) plane of α-Fe₂O₃ is preferentially exposed, almost all the Mo⁶⁺ ions of the dispersed molybdena species existed at the surface octahedral sites for the sample with MoO₃ loading close or beyond the dispersion capacity, and formed the Mo-II species. In this case, the capping O^2- ions linking with the incorporated Mo⁶⁺ ions formed a surface epitaxial structure, which was in good agreement with the results predicted by the incorporation model proposed previously. XRD and Mössbauer spectroscopy of the MoO₃ α-Fe₂O₃ samples calcined at different temperatures showed that the calcination temperature could strongly influence the interaction extent: ( i) at 420 , MoO₃ dispersed on the surface of α-Fe₂O₃ and formed surface Mo species; (ii ) at 500 , MoO₃ reacted with the bulk of α-Fe₂O₃ and formed Fe₂(MoO₄)₃ compound.     

Characterization of γ-Fe2O3 nanoparticles prepared by transfor- mation of α-FeOOH

γ-Fe2O3 nanoparticles were successfully synthesized by a chemically induced transformation of α-FeOOH.In this method,the precursor(α-FeOOH)was prepared by chemical precipitation,and then treated with a mixed FeCl2/NaOH solution to produce the nanoparticles.X-ray diffraction indicated that when the precursor was treated with FeCl2(0.22 mol/L)and NaOH(0.19 mol/L),pure γ-Fe2O3 nanoparticles were obtained.However,when the concentration of FeCl2 was<0.22 mol/L or the concentration of NaOH was<0.19 mol/L,α-FeOOH and γ-Fe2O3 phases co-existed in the nanoparticles.Transmission electron microscopy observations showed that in the samples with co-existing phases,the nanoparticles did not have identical morphologies.The pure γ-Fe2O3 nanoparticles were polygonal rather than spherical.The volume ratio of α-FeOOH and γ-Fe2O3 was estimated for the two-phase samples from magnetization data obtained from a vibrating sample magnetometer.This chemically induced transformation is novel,and could provide an effective route for the synthesis of other metal oxide nanocrystallites.     

The α-dual Differential Geometry of Symmetric Nonsingular Matrices

The manifold S ( n ) is explored. The set of all symmetric nonsingular matrices on which a Riemannian metric is defined and dual α -connections are introduced. Furthermore, the α -dual geometric structure is obtained. Finally, an example is given to illustrate our results.     

聚苯乙烯乙醇胺-Fe(Ⅲ)络合物催化缩醛(酮)反应

报道了高分子金属洛合物催化剂聚苯乙烯乙醇胺与Fe(Ⅲ )络合物 (CPSE -Fe(Ⅲ ) )的合成 ,并研究了它对缩醛 (酮 )反应的催化性能 .主要考察了反应时间、反应物摩尔比、催化剂用量对产物收率的影响及高分子金属络合物催化剂稳定性 .实验结果表明 ,该高分子金属络合物催化剂在温和的条件下能较好地催化环己酮乙二醇的缩酮反应 ;也能催化其他的缩醛 (酮 )反应 ;与产物分离容易 ,可循环使用 ,且操作简单     

Si(100)和Si(111)衬底上的同质分子束外延

由于硅材料在大规模集成和微结构器件中应用最广,工艺最成熟,以硅为基础的分子束外延材料因此而倍受关注.例如,在硅衬底上外延生长Ⅲ-Ⅴ族半导体和在Ⅲ-Ⅴ族半导体上生长硅,有可能使微电子器件和光电子器件集成在同一芯片上;硅/绝缘体/硅和硅/硅化物/硅单晶结构的生长是实现三维集成、提高集成度的有效途径之一.根据现在已有的实验结果和文献报导,要获得一个界面缺陷少、电学和光学特性优良的异质器件,衬底表面的清洁处理和同质分子束外延生长一个缓冲层是器件制备过程中极为主要的.本文选用φ39mm、n型的Si(100)和φ34mm、p型的Si(111)单晶片为衬底,探讨了它们的清洁处理和同质生长条件.     

Al(Ⅲ)-Fe(Ⅲ)共存体系的水溶液化学特征

通过铝铁混合溶液及其加碱后的聚合氯化铝铁溶液的ＰＨ驰豫以及碱滴定实验,揭示了铝铁共存体系的水溶液化学特性,确定了铝铁混合溶液及 聚合氯化铝铁能稳定存在的浓度及经度范围,Ｘ射线衍射分析结果表明,铝铁共存水解聚合趋于生成无定型结构的沉淀物。     

Reconstruction of broken Si–O–Si bonds in iron ore tailings (IOTs) in concrete

This paper reports a study on the reconstruction of broken Si-O-Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The differences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs concrete samples are lower than those of limestone concrete; the diffraction peak of the calcium silicate phase at 2θ=29.5°, as well as the bands of Si-O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)₂.     

Rational Design of a High-Performance KMnO_4-Fe(Ⅱ)-Si Coagulant for Dye Removal

A new ternary coagulant polysilicate ferromanganese(PSFM), composed of Fe, Mn and Si, was designed. Its coagulation performance for dye removal was investigated systematically together with the impact of several key operational parameters. The experimental results indicate that an excellent coagulation efficiency with higher than 95% color removal and higher than 94% total organic carbon(TOC) removal can be obtained at an optimized molar ratio of Si∶Fe∶Mn(5∶5∶1). The coagulation performance of PSFM coagulant was studied comparatively with other conventional coagulants, e.g. poly aluminium chloride(PAC), Al_2(SO_4)_3 and FeCl_3. Additionally, various characterization techniques were applied to get detailed morphological and compositional information of PSFM coagulants. Furthermore, the underlying mechanism for improved coagulant performance was proposed based on these results. These results have exemplified quantitatively that PSFM coagulant exhibits a great potential as a promising material for application in various environmental fields.     

The (Δ+2,2)-incidence coloring of outerplanar graphs

An incidence coloring of graph G is a coloring of its incidences in which neighborly incidences are assigned different colors. In this paper, the incidence coloring of outerplanar graphs is discussed using the techniques of exchanging colors and the double inductions from the aspect of configuration property. Results show that there exists a (Δ+2,2)-incidence coloring in every outerplanar graph, where Δis the maximum degree of outerplanar graph.     

The occurrence of the genus Marrella(Trilobitoidea) in Asia

An important discovery in the Kaili Biota has been made recently, and many interesting components from ChengjiangBiota and Burgess Shale Biota have been discovered. Among them Marrella, only known from mid-Middle Cambrian Burgess Shale Biotaof British Columbia, Canada, is one of the most important arthropods fossils. Because the Kaili Biota is older than the Burgess Shale Biota,the strange head shield of Marrella occurring in the Kaili Biota outside Laurentia ranges from mid-Middle Cambrian to early Middle Cam-brian and is significant for the reconstruction of palaeogeography and evolutionary study of early metazoa. In the present paper Marrellasp. is reported for the first time in Asia.     

The (Δ+2,2)-incidence coloring of outerplanar graphs

An incidence coloring of graph G is a coloring of its incidences in which neighborly incidences are assigned different colors. In this paper, the incidence coloring of outerplanar graphs is discussed using the techniques of exchanging colors and the double inductions from the aspect of configuration property. Results show that there exists a (Δ+2,2)-incidence coloring in every outerplanar graph, where Δis the maximum degree of outerplanar graph.     

硝基苯在钢渣-Fe(Ⅱ)系统中的还原转化

研究了钢渣含铁废物,以及添加Fe(Ⅱ)后钢渣-Fe(Ⅱ)体系对硝基苯还原转化的可行性及化学机理.实验在20±2℃及转速为30 r.min-1条件下进行,结果表明,单独钢渣体系对硝基苯的吸附和还原转化能力有限,其还原能力与钢渣本身残存的还原活性组分Fe(0),FeO有关.钢渣与Fe(Ⅱ)的表面结合系统能够提高硝基苯的还原转化速率.溶液中钢渣量大于12 g.L-1时,混合液pH值范围为11~12,硝基苯可在1h内完全转化.降低钢渣用量使混合液酸碱度稳定在中性,硝基苯转化速率减慢,高效液相色谱分析结果证实硝基苯还原转化遵循硝基苯→亚硝基苯→羟基苯胺→苯胺的途径.     

Ge/Si(100)界面研究

半导体超晶格材料的研究对于飞速发展着的微电子技术和光电子技术有着非常广泛的应用前景.从七十年代初期首次在GaAs半导体表面制成超晶格材料至今,对超晶格材料的研究已扩展到了其他半导体,Si_(?)Ge_(1-x)合金就是一种可在Si表面生长的超晶格材料.研究Si_xGe_(1-x)/Si超晶格首先是从Ge/Si界面的研究入手的,无论是从半导体-半导体界面研究的角度出发还是从实际应用的角度来考虑,如寻找一种便宜衬底材料来生长具有高效的GaAs太阳能电池薄膜等光电器件和GaAs电子器件,Ge/Si这种体系的界面研究就成了一个非常有兴趣的课题.本文用XPS、AES、ELS、CEED等表面手段研究在室温条件下Ge/Si(100)的界面形成.