菱镁材料改性研究进展

从菱镁材料成型机理入手,分析了菱镁材料改性外加剂的改性原理及其改性方法,介绍了改性后的菱镁材料具有的各种优异的性能,指明了菱镁材料改性的应用研究方向。     

Different deformation mechanisms of two modified‐polystyrene bimodal systems

It is well known that the dominant toughening mechanism of rubber‐modified polystyrene is multiple crazing. Some researchers have investigated polystyrene that can be modified by rubbers with dual particle sizes, leading to better mechanical properties. That is, the way to absorb energy during the deformation process is crazing and cavitation induced by rubber particles. Two types of polybutadiene‐graft‐polystyrene (PB‐g‐PS) rubber modifiers which have core‐shell structures were synthesized via an emulsion graft polymerization using redox and oil‐soluble initiators, respectively. To balance the yield strength, general‐purpose polystyrene was blended with the PB‐g‐PS modifiers, as well as commercial high‐impact polystyrene. Blends were defined as R‐bimodal and O‐bimodal corresponding to dispersed PB‐g‐PS particles formed using the redox and oil‐soluble initiators, respectively. The impact strength of R‐bimodal was improved significantly by altering the ratio of core to shell. However, little change of impact strength was observed for O‐bimodal. Transmission electron microscopy images of fracture surfaces indicated that the deformation mechanism of R‐bimodal is shear‐yielding induced by multi‐crazing. Moreover, PB‐g‐PS particles dispersed in O‐bimodal can form a ‘cluster’ structure, leading to crazing to absorb energy. Scanning electron microscopy images also showed obvious distinctness between the R‐bimodal and O‐bimodal systems due to different deformation mechanisms. Copyright © 2010 Society of Chemical Industry     

Power generation from a biocathode microbial fuel cell biocatalyzed by ferro/manganese-oxidizing bacteria

The abiotic cathodes usually require a catalyst such as Pt to enhance power production, increasing the cost and lowering the operational sustainability. In this paper, the performance of a biocathode microbial fuel cell biocatalyzed by ferro/manganese-oxidizing bacteria was investigated. A scanning electron microscopy with an energy-dispersive spectrometer (SEM-EDS) was used to characterize the cathode and analyze the element of cathode. The amount of ferro/manganese-oxidizing bacteria in the biocathode was examined. In batch-fed systems, the maximum open circuit voltage (OCV) was between 700 and 800 mV and the maximum cell potential difference was higher than 600 mV with an external resistance of 100 Ω. The maximum power density was 32 W m⁻³ MFC for batch-fed systems (20-40% Coulombic yield) and 28 W m⁻³ MFC for a continuous system with an acetate loading rate of 1.0 kg COD m⁻³ day⁻¹. The results of SEM-EDS clearly showed that cathode was impregnated with iron and manganese. The amount of ferro/manganese-oxidizing bacteria was (7.5-20.0) × 10⁵ MPN mL⁻¹ in the biocathode. Biocathodes alleviate the need to use noble catalysts for the reduction of oxygen, which step forward towards large-scale application of MFCs.     

Modified Atmosphere Maintains Quality of Fresh-cut Cantaloupe (Cucumis melo L.)

ABSTRACT: Fresh-cut cantaloupe cubes were placed in film-sealed containers in which the internal gas mixture was attained naturally (nMAP), was flushed with 4 kPa O₂ plus 10 kPa CO₂ (fMAP), or was maintained near atmospheric levels by perforating the film (PFP). While both nMAP and fMAP maintained the salable quality of melon cubes for 9 d at 5°C, fMAP maintained quality better than nMAP. The benefit of fMAP was indicated by better color retention, and by reduced translucency, respiration rate, and microbial population compared with nMAP. Shelf life of cubes in PFP was only 5 to 7 d at 5°C, and its rapid decline was due to tissue translucency and/or off-odor development.     

阳离子染料可染改性涤纶纤维染色的研究

从纤维结构及染色工艺对阳离子染料可染涤纶纤维的染色性能进行了研究。探讨了染料用量、pH值、匀染剂用量、和染色时间对染色的影响。通过对比试验得出最佳染色处方和工艺条件为：染料用量0．5％（o．w．f），pH值3．5—4．5，醋酸钠1％（o．w．f），匀染剂12270．5％（o．w．f），浴比1：30，100％染100分钟...     

提高我厂改性沥青感温性能指数

针对我厂改性沥青感温性能指数不达标的原因，用SBS聚合物的改性沥青机理和相分离机理进行了分析，提出了改进措施，并在生产中进行了验证，提高了感温性能指数。     

Monte Carlo studies of ion size effects in the diffuse double layer

Results from Monte Carlo (MC) simulations for restricted electrolytes are presented for both 1:1 and 2:1 electrolytes. It is shown that the potential drop across the diffuse layer for these systems may be expressed by a Taylors series in the Gouy-Chapman (GC) estimate of the same quantity. The coefficients of this series are defined in terms of the MSA volume fraction and the reciprocal thickness of the ionic atmosphere. The series model can also be used to estimate the differential capacity of the diffuse layer. The properties of unrestricted electrolytes are considered at or very close to the potential of zero charge.     

聚酰胺改性氢化蓖麻油在无铅锡膏中的应用研究

通过试验，在免洗松香型无铅锡膏中添加聚酰胺改性氢化蓖麻油，考察其对焊锡膏流变性能及应用性能的影响。其中，测试方法包括粘度、粘着力和抗热塌性测试。聚酰胺改性氢化蓖麻油用量为5g时的焊锡膏的粘度适中、粘着力最大及其抗热塌性最好，会有一个较好的印刷性能。     

基于GPC法的改性沥青SBS含量测试方法研究

采用GPC对不同SBS剂量的改性沥青进行了测试,建立了SBS剂量与GPC测试数值的关系,并采用已知SBS剂量的样品对该方法进行验证。结果显示,GPC测得的SBS含量与SBS真实剂量线性关系良好,SBS剂量相对偏差均在5%以内,表明GPC法是一种检测改性沥青质量的快速、可靠的测试方法。