Zirconium-Embedded Polyhedral Oligomeric Silsesquioxane Containing Phosphaphenanthrene-Substituent Group Used as Flame Retardants for Epoxy Resin Composites

A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr–POSS–bisDOPO) is synthesized by the corner-capping and Kabachnik–Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr–POSS–bisDOPO composites are investigated. The results show that when Zr–POSS–bisDOPO is added by 5–7 wt%, the EP/Zr–POSS–bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal–POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr–POSS–bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si O Si and Zr O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal–POSS hybrid flame-retardant and polymer composites.     

Natural Polysaccharides as Multifunctional Components for One-Step 3D Printing Tough Hydrogels

Natural polysaccharides (NPS) are regarded as biomolecular and structural components for preparing high-performance tough hydrogels. But the one-step fabrication of NPS-containing hydrogels in seconds and the template-free design of complicated high-resolution structures are still significant challenges in this field. To meet these requirements, various NPS-containing tough hydrogels are fabricated and processed into 2D/3D structures via the combination of Ru(bpy)₃²⁺-mediated photochemistry and extrusion 3D printing technique. The whole fabrication process is one-step, completed in tens of seconds under visible light irradiation. It is found that the used NPS plays a key role in achieving the fabrication of high-performance structured tough hydrogels. The high reactivity of functional groups in the used NPS can shorten their gelation times. Long rigid chains of the used NPS, their hierarchical assemblies, and contrasting multinetworks benefit from the efficient dissipation of mechanical energy and enhancement of its operational stability. Strong supramolecular interactions enable hydrogel precursors to have high viscosities, therefore providing good controllability to design high-resolution and complicated tough hydrogel structures via extrusion 3D printing. It is anticipated that this straightforward fabrication strategy and findings will open new horizons for NPS-containing materials.     

High Efficiency Electrochemiluminescence for Copper(II) and Cadmium(II) Pyrazolate Polymers

Journal of Inorganic and Organometallic Polymers and Materials - Two new coordination polymers, namely, [Cu2(L)2(4,4′-bpy)]n (1) and [Cd(HL)Cl(1,10′-phen)]n (2)...     

Revit二次开发在水泥厂三维设计中的应用

随着科学技术的迅猛发展,建筑设计也在由二维向三维发展。近年来,在BIM（Building Information Modeling）建筑信息模型技术被写入建筑业发展“十二五”规划,并且列入住建部、科技部“十三五”等规划之后,BIM的概念逐渐深入人心,相关技术也随之迅速发展。 Autodesk Revit作为一款应用广泛的建筑信息模型三维设计软件,能够从初步设计、参数化、可视化、数据分析等方面提高设计效率和准确性,使用Revit进行水泥厂设计,不仅能使业主和施工人员更加直观的了解生产线布置,还能更好地统计工程量,对于一些复杂的管路布置,可以通过Revit设置条件生成相应的管路、部件明细表便于订货及工程量统计。在现在建筑的不断复杂化,设计要求也不断提高的大环境下,Revit软件自身所带的功能已不能满足现在建筑设计要求,对其二次开发已迫在眉睫[1]。Revit提供了丰富的应用程序编程接口供使用者进行二次开发,通过编程接口,用户可以结合.Net Framework生成动态链接库文件,在Revit用户界面中添加自定义组件,通过程序集成多项操作,自动完成复杂的建模工作,进一步深化三维设计的自动化和智能化,提高设计效率和质量。     

Effect of ammonia concentrations on SCC of α-brass under mode III loading

Stress corrosion cracking (SCC) of α-brass in ammonia solution was studied under mode III loading. The results showed that SCC occurred on the principal stress planes where shear stresses are zero. No SCC occurred on the maximum shear stress plane. Ammonia concentration affected fracture behaviour. When the concentration was low, many cracks with spacing of 10–150 μm were found on 45 ° planes, i.e., the principal stress planes. When the concentration was high, the cracks on 45 ° planes were not clearly visible because of serious general corrosion.     

A New Recycled Al–Si–Mg Alloy for Sustainable Structural Die Casting Applications

Metallurgical and Materials Transactions A - The use of secondary aluminum for structural components in the automotive industry is limited by the high Fe contents in recycled alloys which often...     

Effect of Heat Treatment on Microstructure and Mechanical Properties of Extruded PM Ti–6Al–4V Alloy With Deformation Flowlines

Metallurgical and Materials Transactions A - Two heat treatments, namely 955°C/2h/AC (AC = air cooling) and 955°C/4h/FC (FC = furnace cooling), were carried out on...     

Role of deposition parameters on microstructure and mechanical properties of chromium oxide coatings

Chromium oxide coatings were deposited by reactive magnetron sputtering on high speed steel (HSS) substrate under various oxygen flow rates and radio frequency (RF) powers. The effect of deposition conditions on the microstructure, hardness and critical load of chromium oxide coating failure was studied. The results indicated that a crystalline chromium oxide coating formed at a high oxygen flow rate and a low RF power exhibited a higher hardness and a lower critical load as compared to a chromium oxide coating with an amorphous microstructure.     

挤压铸造模具标准件库的研究与实现

分析了模具标准件库开发的基本思想，基于“尺寸驱动”的参数化建模方法，以SolidWorks为开发平台，VisualBasic为开发工具，使用Access数据库对挤压铸造模具标准件的所有数据进行管理，实现了标准件库系统的创建。在设计过程中可以通过简单的参数输入，达到标准件直接调用的目的。实践证明，该系统避免了设计中复杂的建模工作，缩短了挤压铸造模具开发周期，具有较强的应用价值。