基于磁性共价有机骨架对烤肉中苯并[a]芘的检测

采用快速简单的共沉淀法合成磁性共价有机骨架材料,并通过傅里叶变换红外光谱、透射电镜对其进行表征.通过优化吸附剂用量、萃取时间、解吸溶剂、解吸时间和解吸体积等条件,建立了磁固相萃取-高效液相色谱法测定烤肉中苯并[a]芘(Benzo[a]pyrene,BaP)的新方法.该方法的线性范围为0.5～100.0 μg/L(R2=...     

纳米复合材料Ag/TiO2微波辅助合成与光催化性能

采用EO20PO70EO20(P123)作为模板剂,通过溶胶-凝胶-程序升温溶剂热一步法并经不同时间微波辐射处理,制备了一系列纳米复合材料Ag/TiO2。采用XRD、XPS、TEM、N2吸附-脱附测定和SEM-EDS等测试手段对其组成、结构及形貌等进行表征。结果显示,微波辐射5min制备的Ag/TiO2晶型结构最佳,该产物中Ag以单质形式存在,其比表面积可达100.64m2·g-1,平均孔径约为6.9nm。与未经微波辐射样品相比,其颗粒细小、结构规则、分布均匀、无明显团聚现象。以甲基橙为模型分子,考察经不同时间微波辐射处理的纳米复合材料Ag/TiO2的紫外光催化活性。结果表明,在微波功率为200W,微波时间为5min时获得的Ag/TiO2的催化活性最高,循环使用3次后降解率仍能达到80%以上。     

大型复杂悬臂结构铝合金焊接变形控制研究

研究的结构件为大型复杂悬臂结构铝合金焊接件,因其既有环焊缝又有纵焊缝,焊缝数量多,焊接变形量大,焊接变形趋势复杂,使得通常的工艺加工方法很难满足其设计性能要求。通过对影响焊接变形的几个因素进行详细分析,选择合理的焊接方法、焊接参数,采取有效的工艺措施,通过试验进行验证,圆满地解决了这一难题,此工艺方案完全适用于类似大型悬臂结构件的焊接。     

Graphene oxide nanoribbon and polyhedral oligomeric silsesquioxane assembled composite frameworks for pre-concentrating and electrochemical sensing of 1-hydroxypyrene

1-Hydroxypyrene (1-OHP) is a ubiquitous metabolite of polycyclic aromatic hydrocarbons (PAHs) and has been widely used as a biomarker for evaluation of human exposure to PAHs. In this paper, an electrochemical sensor consisted of graphene oxide nanoribbon (GON)/octa(3-aminopropyl)octasilae quioxane octahydrochloride (OA-POSS) framework films (GON/OA-POSS) modified electrode for pre-concentrating and sensing of 1-OHP was described. The GON/OA-POSS composite films were prepared by hierarchically layer-by-layer assembly via electrostatic interactions. GON, which has higher electrical conductivity than that of graphene oxide, offers residual π-conjugated systems for adsorption of 1-OHP via π–π stacking interaction. Meanwhile, OA-POSS nanocages make the GON layers frameworked to enhance contacting between GON and 1-OHP. When 1-OHP was pre-concentrated on GON/OA-POSS frameworks modified electrode, the response signal and adsorption stability was enhanced significantly. Differential pulse voltammetry was used for direct determination of 1-OHP. The electrochemical sensor calibration curve had a range of 0.1–12.55 μM (R = 0.995) with a detection limit of 0.04 μM. The results showed that the GON/OA-POSS framework films modified electrode established a new way for simple and sensitive analysis of 1-OHP.     

Electroluminescence of zinc selenium (ZnSe) nanocrystals co-doped with poly[2-methoxy-5-(2'-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV)

We have synthesized water soluble zinc selenium (ZnSe) nanocrystals by using mercaotoacetic acid (TGA) as the stabilizer. The synthesized ZnSe nanocrystals were co-doped with poly[2-methoxy-5-(2'-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV) to fabricate an organic/ inorganic hybrid multilayer light-emitting device (LED). The structure of the device was indium-tin-oxide (ITO)/poly (ethylene-dioxythiophene):poly(styrenesul-fonate) (PEDOT:PSS)/MEH-PPV:ZnSe/bathocuproine (BCP)/tris-(8-hydroxylquinoline)-aluminum (Alq3)/Al. We demonstrate that the device has a lower driving voltage and increased current densities and power efficiencies owing to the co-doped ZnSe quantum dots. We obtained good efficiency of the devices when the quality ratio of MEH-PPV and ZnSe quantum dots was 1:1.     

Modified vegetation-erosion dynamics model and its application in typical watersheds in the Loess Plateau

The vegetation-erosion model was applied in three typical watersheds of hilly and gully area in the Loess Plateau in northwestern China to study the dynamic relations between vegetation coverage and soil erosion rate and various stresses. The model was improved by introducing rainfall and runoff factors. Then the modified model was applied in the Luergou and Luoyugou watersheds. The calculation results with the modified model were compared with the results of the original model. The precisioos of simulated vegetation coverage and soil erosion rate with the modified model were greatly improved compared with the original model. Soil erosion rate reduced with increasing vegetation coverage and the human disturbance caused high soil erosion.     

基于DYNAFORM汽车覆盖件冲压仿真分析

在汽车覆盖件的冲压过程中,拉延筋、压边力、板料厚度、润滑和摩擦等条件对冲压成形过程中的回弹均有不同程度的影响.通过运用DYNAFORM对汽车覆盖件冲压过程进行仿真模拟,分析汽车覆盖件在不同冲压条件下的结果,为汽车覆盖件冲压成形工艺优化提供依据.     

深海拖缆质量控制辅助软件的开发与应用

深海拖缆质量控制的主要工作是结合现场处理对仪器组、导航组的采集信息和数据进行检查与汇总,提交质量控制后的地震数据和详细的质量控制班报.在这个过程中,还需要对大量的地震数据、各种辅助数据及文档进行繁琐的运算和统计.深海拖缆质量控制辅助软件就是针对这一需求开发的.这套辅助软件包括质量控制班报系统、导航P1/90文件分析模块和STS文件分析模块三部分.文中详细地介绍了这套软件的特点.     

浅析全面质量管理在航天制造企业中的应用

由于航天产品的特殊性,航天制造企业对产品可靠性要求高,对产品质量要求异常严格。而全面质量管理作为一种先进的质量管理理念,在航天产品的质量控制方面具有很高的实用性;因此,被航天制造企业广泛应用。但其在实际执行过程中,遇到了较多问题。本文针对这些问题进行了系统的分析,并提出了合理化建议。     

浅析电气倒闸误操作原因及其防范

通过对电气倒闸误操作的介绍和具体案例事故的分析,找出产生电气倒闸误操作的原因,提出如何防止电气倒闸误操作的措施。