提高云母氧化铁醇酸面漆防沉性能试验研究

分别采用有机膨润土、气相二氧化硅、聚酰胺蜡3种不同的固体防沉剂,对灰云铁醇酸面漆进行了防沉降试验研究。研究结果表明:有机膨润土与聚酰胺蜡组合,并选择合适的配比,成功解决了灰云铁醇酸面漆沉降和黏度增长的贮存问题。而且制备的灰云铁醇酸面漆低黏(6#黏度杯,<90 s)、高不挥发分(>75%),有利于环境保护。     

负载型碘化钾催化合成甘油碳酸酯的研究

采用浸渍法制备了负载型碘化钾催化剂,并通过二氧化碳、环氧丙烷和甘油合成甘油碳酸酯反应评价其催化活性,发现KI/γ-Al2O3具有最高的活性,甘油的转化率为58.5%,甘油碳酸酯的产率为54.6%。其中,不同比表面的γ-Al2O3载体对于活性组分负载量具有一定的影响,通过BET、XRD等方法对催化剂进行了表征,进一步说明了大比表面的γ-Al2O3载体有利于KI高度分散。实验考察了反应温度、反应物摩尔比、KI负载量对反应结果的影响,得到了最佳的实验参数。同时,通过重复性使用实验,表明催化剂KI/γ-Al2O3具有较好的稳定性。     

Palladium and Copper Cocatalyzed Intermolecular Cyclization Reaction: Synthesis of 5‐Aminopyrazole Derivatives

A novel and efficient palladium and copper co‐catalyzed intermolecular cyclization of acetonitriles with hydrazones has been developed for the synthesis of 5‐aminopyrazoles through C C and C N bond formation. The reaction has the advantages of easily available starting materials, simple manipulation and mild reaction conditions. The reaction involving various substituted acetonitriles and hydrazones proceeds smoothly and 5‐aminopyrazoles are synthesized in good yields. In contrast to the aliphatic and heteroaromatic substrates, the aromatic substrates tend to have a higher degree of reactivity.

     

Dearomatization of Indole Derivatives via Palladium‐Catalyzed C?H Bond Functionalization of Pyrroles: Convenient Construction of Spiroindolenines

An intramolecular palladium(II)‐catalyzed dearomative arylation reaction of indoles via C H bond functionalization was developed, providing access to structurally novel spiroindolenines with moderate to good yields. A one‐pot process for the synthesis of spiroindoline derivatives was also realized.

     

Efficient Catalyst for Both Suzuki and Heck Cross‐Coupling Reactions: Synthesis and Catalytic Behaviour of Geometry‐ Constrained Iminopyridylpalladium Chlorides

A series of geometry‐constrained iminopyridyl‐palladium chlorides were synthesized and characterized. These phosphine‐free palladium complexes were explored for their catalytic activities in both Suzuki and Heck cross‐coupling reactions, achieving turnover numbers as high as 10⁶ towards various aryl bromides, even those containing various functionalities. In addition, the influence of substituents with steric and electronic factors was reflected by the differences observed in their activities.

     

Preparation of antimicrobial activated carbon fiber for adsorption

Journal of Porous Materials - Activated carbon fiber (ACF) is often used as efficient adsorption material for removal of contaminants from water. However, the propagation of microorganism on ACF...     

As-cast microstructure of Al-Zn-Mg-Cu-Zr alloy containing trace amount of Sc

It has been reported that the element scandium(Sc) is the most effective modificator which can significantly refine the grain size, prohibit recrystallization process and increase the strength. Adding trace of Sc in 7000 series aluminum alloys is considered to be an effective way to modify its micros tructure and promote mechanical properties. In order to study the effect of Sc element on ascast microstructure of Al-Zn-Mg-Cu-Zr alloy, ingots containing different amounts of Sc were prepared by ferrous-mold cast. Microstructures were characterized by means of differential scanning calorimeter(DSC), X-ray diffraction(XRD), optical microscope(OM) and scanning electrical microscope(SEM). The results indicate that when the Sc level exceeds a critical concentration,Al_3(Sc,Zr) primary phase would form in the melt and act as an efficient nucleant, resulting in very refined grain and an equiaxed grain structure. Sc element reduces the number of eutectic phases formed during solidification,coupled with an increase in the concentration of major alloying elements retained in the solute. This behavior suggests possible benefits in improving the integrated properties of terminal products.     

黄银春陶瓷作品欣赏

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COW清洗机工作机构改进设计及应用

根据原油储罐机械清洗工艺的需要,对现有的日本COW清洗机工作机构进行了改进设计,并进行了实际的清洗施工应用,效果良好,有效解决了工程中的技术难题,扩大了COW清洗机的应用范围.