Chemical preparation and investigation of Fe-P-B ultrafine amorphous alloy particles

A series of Fe-P-B ultrafine amorphous alloy particles has been prepared by the chemical reduction method The composition and size of the particles have been effectively adjusted.Mossbauer spectroscopy in addition to sonic other techniques has been used to investigate the reaction process,the factors that influence the preparation,the crystallization of the particles,and the interactions between the components within them.The results indicate that the co-deposition of iron,phosphorus and boron atoms in the solution at room temperature forms Fe-P-B amorphous alloy particles,and a preferential bonding of Fe-P bond to Fe-B one exists in the particles.     

南桐煤镜质组非晶结构的X射线衍射研究

本文对经典煤核结构模型评述后，提出了多元非晶煤结构概念。用Ｘ射线衍射方法研究了南桐煤镜质组的原子径各分布，论证了煤大分子中同时存在芳香结构单元和脂环结构单元，它们对Ｘ射线射射强度均有贡献，非晶煤结构的有序性不在于１ｎｍ。     

Moisture effects on the glass transition and the low temperature relaxations in semiaromatic polyamides

The influence of moisture absorption on the primary (glass) transition (T_a or T_g) and the low temperature relaxations of semiaromatic amorphous polyamides synthesized by isomeric aliphatic diamine and metha or para oriented phthalicdiacids has been investigated by means of differential scanning calorimeter (DSC) and dynamic mechanical thermal analyser (DMTA). The glass transition of semiaromatic polyamides was lowered due to the water absorption, and the β and the γ relaxations were as well. From the observed T_g and the difference in the heat capacity, the calculated T_g depression per 1 wt % water content was 12.3 K and the result was in good agreement with the experimental data. The depression of the glass transition may be expressed by the same manner as the plasticization of nylon 6 by water. The depressed β relaxation observed in the specimen containing a few percent of moisture was splitted into two transitions due to the reduction of water content, of which one was the elevation of the T_β and another was the simultaneous appearance of the T_γ, and then the single T_γ solely was observed for the completely dried specimen. The T_γ seemed to be merged into or not to be observed by the large and broad T_β transition when the sample was governed by a few percent of water, then it was emerged from the T_β due to water desorption. Thus, the T_β is believed to arise from the intermolecular hydrogen bonding between water molecules or between water and amide groups in wet polyamides. In addition, the γ relaxation originated from the peptide groups is attributable to the inter- and intramolecular hydrogen bonding between amide groups. © 1997 John Wiley & Sons, Inc. J Polyn Sci B: Polym Phys 35: 807–815, 1997     

Microstructural model for prediction of stress–strain curves of amorphous and semicrystalline elastomers

A fundamental microstructural model was developed to calculate the stress–strain curves of rubbery amorphous polymers and of semicrystalline polymers with a rubbery amorphous phase by numerical simulations. The rubbery amorphous phase was treated by using a version of the theory of rubber elasticity with finite extensibility. Physical entanglements and chemical crosslinks were both allowed. Slippage was implemented by a Monte Carlo algorithm controlled by kinetic parameters such as the activation energy and activation volume for slippage. The crystalline phase was treated in a very idealized manner, including a crude representation of tie chains but not taking the internal structure of the crystallites into account. A two-dimensional embodiment of the model was implemented into software. For amorphous polymers, while lacking truly quantitative accuracy, the model showed sufficiently good agreement with the experimental trends to be used as a qualitative or semiquantitative predictive tool, and it is currently being used in this manner. The more complex semicrystalline version was less accurate and will need to be improved in future work. Most of the limitations of the semicrystalline version could be ascribed unambiguously to specific simplifications made in the software implementation to reduce the amount of computer time required for the calculations. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2715–2739, 1997     

About the Dominance of Mesopores in Physisorption in Amorphous Materials

Amorphous, porous materials represent by far the largest proportion of natural and men-made materials. Their pore networks consists of a wide range of pore sizes, including meso- and macropores. Within such a pore network, material moisture plays a crucial role in almost all transport processes. In the hygroscopic range, the pores are partially saturated and liquid water is only located at the pore fringe due to physisorption. Therefore, material parameters such as porosity or median pore diameter are inadequate to predict material moisture and moisture transport. To quantify the spatial distribution of material moisture, Hillerborg’s adsorption theory is used to predict the water layer thickness for different pore geometries. This is done for all pore sizes, including those in the lower nanometre range. Based on this approach, it is shown that the material moisture is almost completely located in mesopores, although the pore network is highly dominated by macropores. Thus, mesopores are mainly responsible for the moisture storage capacity, while macropores determine the moisture transport capacity, of an amorphous material. Finally, an electrical analogical circuit is used as a model to predict the diffusion coefficient based on the pore-size distribution, including physisorption.     

不同能级加速过滤电弧沉积四面体非晶碳膜的结构和性能

采用过滤阴极真空电弧技术，通过施加0—2000 V衬底负偏压使沉积离子获得不同能级的入射能量，在单晶硅上制备了四面体非晶碳薄膜.拉曼光谱分析表明，薄膜的结构为非晶sp³骨架中镶嵌着平面关联长度小于1 nm的sp²团簇.原子力显微镜研究表明：在低能级、富sp³能量窗口和次高能级，薄膜中sp³的含量越多，其表面就越光滑，应用sp³浅注入生长机制能够圆满地解释薄膜表面形态与离子入射能量之间的关系；但在高 关键词： 四面体非晶碳 过滤阴极真空电弧 能级     

Single‐armed salamo‐like dioxime and its multinuclear Cu (II), Zn (II) and Cd (II) complexes: Syntheses,structural characterizations,Hirshfeld analyses and fluorescence properties

Three multinuclear Cu (II), Zn (II) and Cd (II) complexes, [Cu₂(L)(μ‐OAc)]·CHCl₂ ( 1 ), [Zn₂(L)(μ‐OAc)(H₂O)]·3CHCl₃ ( 2 ) and [{Cd₂(L)(OAc)(CH₃CH₂OH)}₂]·2CH₃CH₂OH ( 3 ) with a single‐armed salamo‐like dioxime ligand H₃L have been synthesized, and characterized by FT‐IR, UV–vis, X‐ray crystallography and Hirshfeld surfaces analyses. The ligand H₃L has a linear structure and C‐H···π interactions between the two molecules. The complex 1 is a dinuclear Cu (II) complex, Cu1 and Cu2 are all five‐coordinate possessing distorted square pyramidal geometries. The complex 2 also forms a dinuclear Zn (II) structure, and Zn1 and Zn2 are all five‐coordinate bearing distorted trigonal bipyramidal geometries. The complex 3 is a symmetrical tetranuclear Cd (II) complex, and Cd1 is a hexa‐coordinate having octahedral configuration and Cd2 is hepta‐coordinate with a pentagonal bipyramidal geometry, and it has π···π interactions inside the molecule. In addition, fluorescence properties of the ligand and its complexes 1 – 3 have also been discussed.     

Morphology and degradation of biodegradable poly(L-lactide-co-β-malic acid)

Poly(L -lactide-co-β-malic acid) was obtained after the hydrogenolysis of the copolymer of L -lactide (L-LA) and β-benzyl malate (MA). ¹H-NMR demonstrated that the composition of the copolymer was identical to the feeding dose. Thermal property study revealed the morphology of the copolymer could be changed from semi-crystalline to amorphous with increasing hydrophilic β-malic acid content. The copolymers with 8 and 13 mol% β-malic acid content possessed enough mechanical property for fabricating cell scaffold. Degradation result demonstrated that most of the hydrophilic β-malic acid units broke down from the copolymer within 1 week and the ester bond between L -lactide and β-malic acid hydrolyzed prior to the inner ester bond of poly(L -lactide) (PLLA). Copyright © 2003 John Wiley & Sons, Ltd.     

Thermal evolution of ferromagnetic metallic glasses

A traditional TG apparatus was modified by placing two permanent magnets producing a controlled magnetic field (TG(M): Magneto Thermogravimetry). This technique proved to be useful to study both structural relaxation and crystallisation of ferromagnetic metallic glasses. Results obtained for the amorphous alloys Fe₄₀Ni₄₀P₁₄B₆ and Fe_62.5Co₆Ni_7.5Zr₆Nb₂Cu₁B₁₅, are reported in this paper. Structural relaxation can be evaluated by measuring changes in Curie temperature induced by thermal treatments. Crystallisation in TG(M) is detected through a change in the measured apparent mass (difference between the sample mass and magnetic force driving it upward). These results were confirmed by DSC analysis. Whether the obtained crystalline phase is ferromagnetic, it can be identified through its Curie temperature, measured by TG(M). In fact the value of 770°C measured as Curie temperature of crystallised Fe_62.5Co₆Ni_7.5Zr₆Nb₂Cu₁B₁₅led to conclude that the only ferromagnetic crystalline phase is a-Fe. These hypothesis was confirmed by XRD analysis, showing that the first crystallisation yields to a-Fe nanocrystals. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal coefficient of linear expansion of non-crystalline chalcogenides in the As-S-Se-Te-I system

The object of the paper is an investigation of the glasses of the (As₂S₃)_x(AsSe_0.5Te_0.5I)_100-x. type for 65≤;x≤;95, using methods of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid and visco-plastic phase were determined. it was shown that introducing arsenic-sulfide in glass-matrix AsChI, i.e. (AsSe_0.5Te_0.5I), leads to an increasing stability of these glasses. The characteristic temperatures of softening Tg and the temperature of the beginning of deformation t_w increase by increasing content of As₂S₃. The analytical forms of dependence of four significant physical values α_g, α_l, Tg, Tw, as a function of As₂S₃ content in the structure of glasses were fitted. This revised version was published online in July 2006 with corrections to the Cover Date.