5182铝合金表面锆化膜的制备及其性能研究

目的提高5182铝合金的耐蚀性能及与有机漆膜的结合力。方法采用氟锆酸试剂与5182铝合金反应制备锆化膜,探究锆化液pH值、浸泡时间对锆化膜耐蚀性能的影响,并优化制膜工艺。采用SEM、EDS能谱仪及超薄切片仪分析锆化膜的微观结构和成分,结合SKPFM分析合金中第二相颗粒的电位对锆化膜形成机理的影响,采用EIS对锆化膜的耐蚀性能进行评价分析,采用涂层附着力自动划痕仪评价锆化涂层对巴斯夫有机漆膜结合力的影响。结果制备锆化膜的最佳工艺为:pH=4.5,浸泡时间2.5 min。在5182铝合金表面制备了一层50～100 nm厚的锆化膜,且该锆化膜优先在阴极性的第二相颗粒上形成。EIS分析表明,在Na_2B_4O_7×10H_2O和NaOH水溶液中,锆化处理试样的低频阻抗值比未锆化处理试样高80?。划痕测试表明,锆化处理试样与未锆化处理试样相比,其临界载荷提高了75%。结论经过锆化最佳工艺处理后,5182铝合金的耐蚀性能提高,且锆化涂层作为中间层,能显著提高有机漆膜与合金基体的结合强度。     

Physical Properties of Soy Bean and Broad Bean 11S Globulin Gels Formed by Transglutaminase Reaction

Physical properties of transglutaminase-induced glycinin and legumin gels were compared with thermally induced gels. Results of deformation tests showed that transglutaminase-induced gels were more rigid and elastic than thermally induced gels. From creep compliance tests, all elastic moduli and viscosities except Newtonian viscosity were higher for transglutaminase-induced gels. Electron micrographs revealed that network structures of transglutaminase-induced gels were composed of larger unit particles forming more developed strands and clusters. More rigid and elastic gels were formed from glycinin as compared to legumin by both gelling methods.     

Aperiodicky conditions for polynomials with uncertain coefficient parameters

Aperiodicity is normally defined as a property such that all the roots are simple and negative real, while interval polynomials are referred to as polynomials with coefficients lying within specified closed intervals on the real axis. Several conditions for aperiodicity, including an exact one, are derived. Comments on these conditions are given in contrast to the work of Soh and Berger, who also considered the problem with a modified definition of aperiodicity.     

Winding Method to Reduce Vibration and Loss Caused by Fractional Slot of Synchronous Machine

Fractional‐slot windings are widely used in rotating machines in order to improve the output voltage waveform, increase the design flexibility, and gain many other advantages. However, fractional‐slot windings are known to produce different harmonic components such as an even order and/or fractional number of space flux harmonics compared to integral‐slot windings. These harmonics may increase stray losses and cause stator core vibration. This paper describes an analysis of space flux harmonics and proposes new winding methods such as “novel interspersed windings” to reduce these harmonic components. The proposed winding methods were verified by numerical analysis and model tests.     

高灰熔点煤高温下煤焦CO2/水蒸汽气化反应特性的实验研究

我国煤炭年产量中，1400℃以上的高灰熔点煤约占50％以上。为探索固态排渣方式的高灰熔点煤气流床气化，本文选出具有代表性的三种高灰熔点煤种和一种低灰熔点煤种，在TGA-51H型高温热天平上进行了煤焦-CO2和煤焦-水蒸汽气化反应特性的实验研究，并利用SEM考察了气化条件下煤焦及灰的微观结构。实验结果表明：在煤焦-CO2、H2O反应过程中，反应速度明显表现出高温区域的扩散反应和低温区域的化学反应；无论在1273K～1573K的低温区域，还是在高于1573K的高温区域，反应速率随燃料比（FC/V）的增加而减小。     

Computational complexity of spline interpolation

The procedure for composing the spline function of order m that interpolates n data is roughly divided into two stages: (1) constructing the matrix A_n that transforms the fl-spline coefficient vector c into the sample value vector s; and (2) calculating the vector c. Then the effects of boundary conditions and the locations of the sampling points and the knots on the number of computations for spline interpolation are evaluated. There are no boundary condition effects of the construction of A" for equispacing. Non-periodic boundary conditions reduce the number of computations needed to calculate c from O(m²n) to O(m²n/4).

In the construction of A_n, choosing equispaced sampling points reduces the number of computations from O(m²n) to O(m²) in the case of sampling points located at a constant interval between each pair of adjacent knots. In the calculation of c, equispaced sampling points reduce the number of computations from O(m²n) to O(m²n /2) in the case where m is even and the locations of the knots are identical with those of the sampling points.     

EFFECT OF HIGH PRESSURE ON THE ACCUMULATION OF IMP AND ON THE STABILITY OF AMP DEAMINASE IN RABBIT SKELETAL MUSCLE

This study evaluated the effect of high pressure on rabbit skeletal muscle, specifically on the production of inosinic acid (IMP), one of “umami” components, and on the activity of adenosine triphosphate (AMP) deaminase, which plays a role in the conversion of AMP to IMP. By increasing the pressure (0.1 to 300 MPa), nucleotide analysis showed that IMP content in muscle increased instantly with a concomitant decrease in ATP content. The IMP content of muscle at 300 MPa was approximately 15% higher than with lower pressures (0.1–200 MPa) when stored for 1 week at 4C after pressurization. These results suggested that the metabolism of nucleotides in muscle was not significantly impaired by pressure treatment. At 300 MPa, AMP deaminase maintained approximately 70% of the activity at 0.1 MPa. In contrast, the activity of purified AMP deaminase was completely lost at 200 MPa, and irreversible conformational changes were observed by in situ fluorescence spectroscopy. These results indicated that purified AMP deaminase was irreversibly denatured under pressure as high as 300–400 MPa.     

Difference of histology and elemental composition of the cervical enamels among human permanent teeth

The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among the human permanent teeth. The re-ground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.