液压脉振注塑PP/CaCO3的结构与力学性能

采用自制的液压脉振式动态注塑机在不同浇口条件下注射成型聚丙烯(PP)/CaCO3复合材料,通过拉伸及冲击性能测试、扫描电镜(SEM)分析和差示扫描量热(DSC)分析研究了PP/CaCO3复合材料的结构与力学性能.研究表明,浇口尺寸对振动效应有影响,浇口截面尺寸越大,振动效应越大;相对于小浇口,中、大浇口条件下动态注射成型复合材料的拉伸强度、冲击强度均有明显的提高l液压脉振有利于CaCO3在PP中的分散.相对于小浇口,大浇口条件下动态注射成型PP/CaCO3复合材料中的CaCO3分布更均匀,同时复合材料熔点更高,结晶度更高,这些均有助于提高复合材料的力学性能.     

电信级以太网关键技术分析

文章在简单介绍了城域网的发展趋势后,从扩展性、QoS、安全、可靠性、管理5个角度,详细分析了目前几种主流电信级以太网技术在具体实现上的异同,同时针对性地介绍了几个解决问题的关键方法.     

3D optical vortices generated by micro-optical elements and its novel applications

In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communi- cation     

海平面上宇宙射线电离量的测定及其影响因素的讨论

用自制的圆柱形钢壁充氩高气压电离室在三个不同海拔高度的湖面上,测量了宇宙射线电离量,进而外推出海平面上宇宙射线电离量值为(2.13±0.13)I。又根据在渤海海域的直接测量数据,与上述值比较,得出在渤海测量时所乘钢制船体的γ放射性影响为0.43I(相当于0.74μR/h)。对于测量中若干影响因素进行了初步分析和讨论,认为周围环境物质(例如钢制船体)中天然放射性核素的γ放射性和常压(1atm.)电离室室壁的α发射是影响海平面上宇宙射线电离量数据一致性的两个主要因素。     

Q345B钢动态再结晶动力学模型研究

在Gleeble1500热模拟机上进行Q345B钢单道次压缩变形实验,得到其真应力-真应变曲线,结合加工硬化率曲线,确定了Q345B钢动态再结晶临界应变εc、峰值应变εP和稳态应变εs。根据实验结果得到Zener-Hollomon方程和动态再结晶状态图,利用Johnson-Mehl-Avrami（JMA）方程法得到再结晶体积分数实际值,采用3种不同的再结晶体积分数预报模型对实验数据进行回归,并对再结晶体积分数实测值和预报值进行对比。结果表明,Epsilon-S／Epsilon-C模型精度最高,Epsilon-S模型精度次之,Epsilon-P模型精度最差。     

Creating a high-quality wool-oriented Turkish merino herd and investigation of mechanical and dyeability properties of fabrics produced from Turkish merino in comparison with Australian merino

Today, the need for quality wool suitable for worsted fabric production in the world is mainly met by Australian merino wool. In Turkey, which has a significant sheep population, in addition to domestic breeds, approximately 10% of the total sheep population (around four million head) is composed of merino cross breeds. However, the fleece quality is far from meeting Australian merino wool standards. Therefore, the aim of this study is to ensure a merino herd with high-quality wool in Turkey. For this aim, by carrying out field studies in the Thrace region of Turkey where Turkish Merino sheep are widely bred, sheep with fleece that can meet the demands of the worsted industry were determined. As a result of field studies in which thousands of sheep were examined, it was determined that 43 female and 10 male sheep had fleece that would meet these standards. Then the breeders of the sheep, which had quality fleece, were persuaded and these sheep were purchased, and “Turkey's wool-oriented Turkish (Karacabey) Merino Herd” consisting of 30 sheep and three rams was formed in the farm of Tekirdağ Namık Kemal University. In the second part of this study, a 100% wool fabric produced by using Australian merino was taken as a reference and it was aimed to produce the same fabric from Turkish merino wool. For this aim, the wool-oriented Turkish Merino herd, which was bred at the university farm for 1 year, was shorn in May 2022. Then, Turkish and Australian merino wools were first converted into worsted yarn and then into woven fabric. The results of mechanical (tensile strength, pilling, abrasion resistance, felting shrinkage, Hofmann dimensional change, bending stiffness) and dyeability (dye-uptake, CIE L*a*b* and colour yield (K/S) values; washing, rubbing and light fastness values) properties of fabrics produced from Turkish and Australian merino wool is presented.     

Synthesis,calcination and characterization of Nanosized ceria powders by self-propagating room temperature method

Nanometric ceria powders with fluorite-type structure were obtained by applying self-propagating room temperature method. The obtained powders were subsequently thermally treated (calcined) at different temperatures for different times. Powder properties such as specific surface area, crystallite size, particle size and lattice parameter have been studied. Roentgen diffraction analysis (XRD), BET and Raman scattering measurements were used to characterize the as-obtained (uncalcined) powder as well as powders calcined at different temperatures.It was found that the average diameter of the as-obtained crystallites is in the range of 3–5 nm whereas the specific surface area is about 70 m²/g. The subsequent, 15 min long, calcination of as-obtained powder at different temperatures gradually increased crystallite size up to ～60 nm and reduced specific surface down to 6 m²/g. Raman spectra of synthesized CeO_2?y depicts a strong red shift of active triply degenerate F_2 g mode as well as additional peak at 600 cm^?1. The frequency of F_2 g mode increased while its line width decreased with an increase in calcination temperature. Such a behavior is considered to be the result of particle size increase and agglomeration during the calcination. After the heat treatment at 800 °C crystallite size reached value larger than 50 nm. Second order Raman mode, which originates from intrinsic oxygen vacancies, disappeared after calcination.     

8-氟-5-甲氧基-1,2,4-三唑并[4,3-c]嘧啶-3(2H)-硫酮的合成

以5-氟尿嘧啶为起始原料,经氯代反应、醇解反应、肼解反应和环合反应合成了高效除草剂双氟磺草胺的关键中间体—8-氟-5-甲氧基-1,2,4-三唑并[4,3-c]嘧啶-3(2H)-硫酮。以5-氟尿嘧啶计,产品总收率达70.1%,产品结构经核磁共振分析验证。探讨了原料配比、反应温度、时间等因素对反应收率的影响。     

煤直接液化残渣热解特性研究

介绍了煤直接液化残渣热解特性的基础实验研究,主要为温度对液化残渣干馏产物产率及性质的影响,给出了部分煤直接液化残渣热解特性基础数据,可为液化厂液化残渣的回收利用提供参考。     

铝-氮化铝结合刚玉质滑板的抗氧化性能

研究了铝-氮化铝结合滑板在氧化气氛下加热升温过程中质量的连续变化特征,以及氧化前后试样的外形尺寸和强度的变化,通过热力学计算和动力学分析得知,试样在氧化过程中表现出的质量变化特性,有助于其组织结构的致密,特别是金属铝的氧化使得其在高温下形成氧化隔离层,提高了滑板的抗侵蚀能力和抗渗透能力。