CAU9901的高效液相色谱分析

报道了新型植物生长调节剂CAU9901的高效液相色谱分析方法。该方法快速简捷,精密度变异系数为0.49%,相关系数为1.000 4,准确度回收率在98.89%~100.1%之间。     

5-烷基-2-氨基-1,3,4-噻二唑的合成及应用

用硫代氨基脲与甲酸、乙酸、丙酸、丁酸、异丁酸、异戊酸等在盐酸、磷酸、多聚磷酸、硫酸催化下 ,分别合成了 2 -氨基 -1 ,3 ,4-噻二唑 (a)、5 -甲基 -2 -氨基 -1 ,3 ,4-噻二唑 (b)、5 -乙基 -2 -氨基 -1 ,3 ,4-噻二唑 (c)、5 -丙基 -2 -氨基 -1 ,3 ,4-噻二唑 (d)、5 -异丙基 -2 -氨基 -1 ,3 ,4-噻二唑 (e)、5 -异丁基 -2 -氨基 -1 ,3 ,4-噻二唑 (f)。并对工艺条件进行了试验 ,结果表明 :最佳工艺条件为硫代氨基脲与酸的摩尔比为 1∶ 1 .4,合成 2 -氨基 -1 ,3 ,4-噻二唑为多聚磷酸催化 ,合成其它的为浓盐酸催化 ,回流 3 h,产率分别为 96.78%、74.3 4%、73 .67%、71 .68%、68.44%、67.5 4%。同时以 a～f为原料合成了具有抗菌作用的 5 -烷基 -1 ,3 ,4-噻二唑硫脲乙酸和 5 -烷基 -2 -苯基 -硫脲 -1 ,3 ,4-噻二唑的衍生物     

Numerical Simulation of Oil‐water Hydrocyclone Using Reynolds‐Stress Model for Eulerian Multiphase Flows

A three‐dimensional oil‐water turbulent flow and oil separation process in a double‐cone liquid‐liquid hydrocyclone (LLHC) is numerically simulated using FLUENT software. The Euler‐Euler approach and Reynolds‐stress model are combined and adopted in this simulation to handle the challenging situation of anisotropic turbulent two‐phase flow with a higher volumetric ratio (over 10%) in the dispersed phase. It is visualized well in the simulation how separation, aggregation and shift of oil and water proceed in the LLHC. The oil separation efficiency is determined based on flow field and phase concentration distribution. The simulation is verified by comparing predicted and measured separation efficiency in the LLHC.     

使用KQ-1缓蚀阻焦剂,减轻糠醛装置腐蚀和结焦

独山子炼油厂糠醛精制装置设备腐蚀状况严重 ,尤其是加工高酸值原料 ,更加剧了设备的腐蚀。通过对腐蚀原因分析 ,决定从工艺防腐上解决 ,提出了加入缓蚀剂减缓设备腐蚀的方法 ,在实验室评价和工业装置中 ,评选了四种糠醛精制装置的缓蚀剂 ,其中KQ 1作为装置缓蚀剂效果最佳 ,平均缓蚀率达到 4 4 .5 % ,并估算了KQ 1工业使用的经济效果     

Manipulating the microstructure and rheology in polymer‐organoclay composites

A series of nanocomposites prepared by melt‐blending of cloisite‐based organoclays with poly(ethylene‐vinylacetate) (EVA) and neutralized poly (ethylene‐methacrylic acid) (EMA) copolymers were investigated via DSC, small‐angle X‐ray scattering (SAXS), and rheological techniques. SAXS results indicated partial clay exfoliation in all samples. In both EMA and EVA systems, the nominal melting temperature T_m and bulk crystallinity are not significantly affected by the presence of organoclays, suggesting that clay particles are predominantly confined in the amorphous phase. In rheological measurements (above T_m), the EVA‐clay system demonstrated a solid‐like rheological behavior under the small‐strain oscillatory shear, yet it was able to yield and flow under a steady shear, which is the characteristic of physical crosslinking. In contrast, the EMA‐clay system exhibited a melt‐like rheological behavior, where the influence of organoclay on the thermorheological behavior of the EMA composite was quite minimal. We propose that the carbonyl groups of vinylacetate in EVA interact with the clay surface, resulting in a strong physically crosslinking like interaction in the melt. On the other hand, the interaction between EMA and clay is weak because of repulsion between carboxyl anions and negatively charged clay surface.     

影响株洲火车站广场空气质量的因素研究

为了探究影响火车站广场污染物(总悬浮颗粒物和可吸入颗粒物)质量浓度的因素,以株洲火车站广场为研究对象,对总悬浮颗粒物和可吸入颗粒物质量浓度与人流密度、车流量的变化关系进行了试验性研究。结果表明,总悬浮颗粒物质量浓度与人流密度、车流量都呈正相关,其主要影响因素是车流量;可吸入颗粒物质量浓度与人流密度呈正相关,与车流量不呈明显的正相关,其主要影响因素是人流密度。细菌和病毒以可吸入颗粒物为载体被人体吸入而致病,因此人们活动时应尽量避开广场人流密度大的地方。     

轴向开槽对改善超磁致伸缩材料线性度影响的研究

磁致伸缩应变与磁场关系的非线性,影响了磁致伸缩控制元件的精度和稳定性。文章针对这一问题,在超磁致伸缩式微小型高速开关阀驱动部件设计基础上,提出了沿超磁致伸缩棒(GMM)轴向开槽的方法来改善GMM部件的工作性能。通过对轴向开槽前后GMM棒内部磁场强度和焦耳热分布的数值计算,分析了轴向开槽对改善磁场强度的分布和减少热损耗功率的影响,通过对GMM棒开槽前后伸缩量的测试,验证了开槽可以明显改善超磁致伸缩材料组件的非线性。     

基于自相似流量检测的DDoS攻击及防御研究

DDoS攻击是目前互联网中应用最广泛,也是危害性最大的一种攻击方式,以破坏网络服务的可用性为目标。文章首先介绍了DDoS的攻击原理,并重点对DDoS的攻击方式和基于自相似网络流量的DDoS攻击检测方式进行研究,最后针对目前DDoS攻击的防御方式进行了全面解析。     

Thermogravimetric analysis of methyl methacrylate‐graft‐natural rubber

The thermal degradations of methyl methacrylate‐graft‐natural rubber (MG) at different heating rates (B) in nitrogen were studied by thermogravimetric analysis. The results indicate that the thermal degradation of MG in nitrogen is a one‐step reaction. The degradation temperatures increase along with the increment of heating rates. The temperature of initial degradation (T₀) is 0.448B + 362.4°C, the temperature at maximum degradation rate, that is, the peak temperature on a differential thermogravimetric curve (T_p) is 0.545B + 380.7°C, and the temperature of final degradation (T_f) is 0.476B + 409.4°C. The degradation rate at T_p is not affected by B, and its average value is 48.9%; the degradation rate at T_f is not affected by B either, and its average value is 99.3%. The reaction order (n) is 2.1 and is not affected by B. The reaction activation energy (E) and the frequency factor (A) increase along with B, and the apparent reaction activation energy (E₀) is 254.6 kJ/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2952–2955, 2002     

基于自适应多普勒及动态邻域的改进BA算法

蝙蝠算法（Bat Algorithm,BA）是一类新型元启发式算法,针对其在算法后期寻优精度降低、易陷入局部极值的不足,提出一种具有自适应多普勒策略及动态邻域策略的改进算法。根据蝙蝠个体在捕食过程中与猎物间存在的相对运动现象,引入自适应多普勒策略改进频率参数,增强算法全局探索的寻优能力。将动态邻域策略与BA算法有机结合,增加蝙蝠个体寻优结构的多样性,改善算法易陷入局部最优的不足。从理论上分析了改进后算法的收敛性和运算复杂性。在数值实验部分对改进后的算法进行了性能及应用测试：对10个经典标准测试函数在不同维度下进行对比实验,将其应用于求解螺旋压缩弹簧优化设计问题,并与其他算法进行了对比分析。实验结果证明了具有自适应多普勒策略及动态邻域策略的改进算法具有更优的收敛速度、收敛精度以及稳定鲁棒性。