A DSC and Raman spectroscopic study of microspheres preparedwith polar cosolvents by different techniques

A study was made of the possibilities of gradually decreasing the concentration of the toxic organic solvent in the process of microsphere preparation. Ammonio methacrylate copolymer-based microspheres were prepared by spray drying or conventional solvent evaporation techniques, and compared. The formulations were designed by varying the preparation methods and the concentrations of four polar cosolvents as independent variables. DSC was used to study the relationship between the changes in the independent variables and three of the main thermal events of the microspheres. Raman spectroscopy was used to investigate and confirm the possible interactions between drug and copolymer. Appropriate choice of the independent variables led to the molecularly dispersed drug in the polymer matrix. It was demonstrated that only the nature of the preparation method caused significant variations in the structure and thermal behaviour of the microspheres.     

学术期刊学者型编辑的研究方向及发展路径

针对编辑专业发展面临的学术研究瓶颈问题,探讨学术期刊编辑可以选择的研究方向及发展路径。结合学术期刊编辑的工作及自身学术发展的经历,从选择研究方向、开展学术研究、开启学术生涯等方面介绍努力发展成为学者型编辑的路径。学术期刊编辑可以结合自身服务的学术领域选择“科研论文写作”“科学研究方法”“薄弱研究主题”等作为研究方向,实现发展成为学者型编辑的目标。学者型编辑的发展与期刊的发展是相辅相成、密不可分的,学者型编辑可以促进学术期刊的发展,学术期刊也可以滋养编辑的发展。     

Corrosion resistance of amorphous AlPO4 coating in salty atmospheres

The objective of the present study was to introduce a cost-effective and environmentally friendly coating to improve the corrosion resistance of the structures located in salt water. The coating solution, based on amorphous aluminum phosphate composition, was synthesized by sol–gel process and applied to AISI 304 stainless steel by dip coating technique. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses were employed to investigate the phase composition and morphology of the coating. Corrosion behavior of the uncoated and coated samples was investigated using standard salt spray test, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Salt spray test results for the bare substrate revealed a corrosion rate of six-time greater than that of the coated surface after 168 hr exposure time. Electrochemical test results declared that the amorphous AlPO₄ coating decreased the corrosion current density of the AISI 304 stainless steel by 10 orders of magnitude. Furthermore, according to the corresponding EIS measurements, the coated surface exhibited a superior anti-corrosion performance than uncoated sample. Overall, the results declared that the amorphous AlPO₄ coating could be a good choice for surface protection of stainless steel against electrochemical corrosion in salty environments.     

一种新型喷嘴的提出及流量特性的研究

本文在对各种气动喷嘴及其雾化机理分析基础上提出了一种新型的气动雾化喷嘴-"旋转型气-液雾化喷嘴"。在此喷嘴中,油与气分别从不同的槽道切向进入混合室,且油与气一一对应,油与气互相混合、旋转后从喷口喷出。其气液比在热态实验时为4%-6%(用压缩空气雾化),雾化状态良好。本文中对其流量系数及雾化角进行了系统的研究。主要考虑了喷嘴的结构参数,气液比(ALR),液体粘度等因素对流量系数的影响。通过实验测量与拟合,最后得到了喷嘴的流量系数和雾化角的表达式,可以用来指导喷嘴的设计。     

CONSTRUCTION OF SOME KIESSWETTER-LIKE FUNCTIONS-THE CONTINUOUS BUT NON-DIFFERENTIABLE FUNCTION DEFINED BY QUINARY DECIMAL

In this paper, we construct some continuous but non-differentiable functions defined by quinary dec-imal, that are Kiesswetter-like functions. We discuss their properties, then investigate the Hausdorff dimensions of graphs of these functions and give a detailed proof.     

On truncation error bound for multidimensional sampling expansion laplace transform

The truncation error associated with a given sampling representation is defined as the difference between the signal and an approximating sumutilizing a finite number of terms. In this paper we give uniform bound for truncation error of bandlimited functions in the n dimensional Lebesgue space Lp(R^n) associated with multidimensional Shannon sampling representation.     

ON A CLASS OF BESICOVITCHFUNCTIONS TO HAVE EXACT BOX DIMENSION： A NECESSARY AND SUFFICIENT CONDITION

This paper summarized recent achievements obtained by the authors about the box dimensions of the Besicovitch functions given byB(t) := ∞∑k=1 λs-2k sin(λkt),where 1 ＜ s ＜ 2, λk ＞ 0 tends to infinity as k →∞ and λk satisfies λk 1/λk ≥λ＞ 1. The results show thatlimk→∞ log λk 1/log λk = 1is a necessary and sufficient condition for Graph(B(t)) to have same upper and lower box dimensions.For the fractional Riemann-Liouville differential operator Du and the fractional integral operator D-v,the results show that if λ is sufficiently large, then a necessary and sufficient condition for box dimension of Graph(D-v(B)),0 ＜ v ＜ s - 1, to be s - v and box dimension of Graph(Du(B)),0 ＜ u ＜ 2 - s, to be s uis also lim k→∞logλk 1/log λk = 1.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Hausdorff measures of a class of Sierpinski carpets

thenandIn this paper, a lemma as a new method to calculate the Hausdorff measure of fractal is given. And the exact values of Hausdorff measure of a class of Sierpinski sets which satisfy balance distribution ang dimension ≤1 are obtained     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.