Zirconia-alumina multiphase ceramic fibers with exceptional thermal stability by melt-spinning from solid ceramic precursor

Zirconia-alumina multiphase ceramic fibers with 80 wt% (Z80A20 fiber) and 10 wt% (Z10A90 fiber) proportions of zirconia were prepared via melt-spinning and calcination from solid ceramic precursors synthesized by controllable hydrolysis of metallorganics. The zirconia-alumina multiphase fibers had a diameter of about 10 µm and were evenly distributed with alumina and zirconia grains. The Z80A20 and Z10A90 ceramic fibers had the highest filament tensile strength of 1.78 GPa and 1.87 GPa, respectively, with a peak value of 2.62 GPa and 2.71 GPa. The Z80A20 ceramic fiber has superior thermal stability compared to the Z10A90 ceramic fiber and a higher rate of filament strength retention due to the stability in grain size. After heat treatment at 1100 °C, 1200 °C, and 1300 °C for 1 h respectively, the filament tensile strength retention rate of Z80A20 ceramic fibers was 87 %, 80 %, and 40 %. While Z10A90 ceramic fiber was fragile after being heated at 1300 °C. The results showed that the high zirconia content facilitated the fiber's thermal stability.     

Novel branched sulfonated polyimide membrane with remarkable vanadium permeability resistance and proton selectivity for vanadium redox flow battery application

A series of novel branched sulfonated polyimide (bSPI-x) membranes with 8% branched degree are developed for application in vanadium redox flow battery (VRFB). The sulfonation degrees of bSPI-x membranes are precisely regulated for obtaining excellent comprehensive performance. Among all bSPI-x membranes, the bSPI-50 membrane shows strong vanadium permeability resistance, which is as 8 times as that of commercial Nafion 212 membrane. At the same time, the bSPI-50 membrane has remarkable proton selectivity, which is four times as high as that of Nafion 212 membrane. The bSPI-50 membrane possesses slower self-discharge speed than Nafion 212 membrane. Furthermore, the bSPI-50 membrane achieves stable VRFB efficiencies during 200-time charge-discharge cycles at 120–180 mA cm^?2. Simultaneously, the bSPI-50 membrane exhibits excellent capacity retention compared with Nafion 212 membrane. All results imply that the bSPI-50 membrane possesses good application prospect as a promising alternative separator of VRFB.     

From fundamental understanding to innovative developments of high-performance composites for aerospace application

In framework of the National Key Basic Research Program (973 Program) we focus our attention on R&D of (1) continuous enhancement of composites performance both for new generation and existing materials, (2) cost-effective manufacturing technologies, particularly resin transfer molding (RTM) in conjunction with textile technology, and (3) crashworthy composite structures in design, and manufacturing and simulation methodology for aircrafts composites. Many successful examples stories such as ex-situ concept have been demonstrated that the performance potential of composites could be enhanced and maximized by basically understandirg the complicated multi-scale and multi-dimensional structural characteristics in relation to properties. Based on the concept, graphite composites system with generally high impact damage resistance and balanced processing conditions has being developed consisting of base resins, modifiers and binders/tackifiers.     

改性方式对膨润土性能及微粒助留助滤效果的影响

采用中性试剂氟化钠对钙基膨润土进行改性制备膨润土悬浮液和膨润土固体粉末,并分别与CPAM组成微粒助留体系。X-衍射分析表明,中性改性剂氟化钠在用量4%时都可以将膨润土中的Ca2 交换完全;透射电镜观察、膨胀倍、胶质价、粒度、粘度、Zeta电位测定和动态滤水实验表明,相对于膨润土固体粉末,膨润土悬浮液颗粒呈完全剥离的片状结构,具有更好的胶体与分散性能,粒度小、悬浮液流动性好且对二次纤维具有更好的助留助滤效果,尤其是放置四周后仍能保持其良好的助留助滤效果。     

利用粗纤维类农副产品开发新型钻井液

采用来源广泛、价格低廉的粗纤维类农副产品，通过物理的和化学的方法进行处理，采用正交试验法等优化设计手段，研制出符合钻井要求的新型钻井液。实验证明，这种钻井液具有较好的滤失性和抑制性，稳定性强，防塌效果好，抗盐侵和抗钙侵等抗污染性能良好。这些材料能部分替代现有(主要为进口)价格昂贵的钻井液材料，而且能通过调整配方，形成用途广泛和适用不同地层的系列产品，并将应用于石油、天然气、地下水和基础工程等钻井领域。     

植物纤维打浆及其对无石棉胶乳抄取板强度的影响研究

研究了植物纤维的打浆性能及其在特种纸无石棉胶乳抄取板中的应用，结果表明：随着磨浆转数的增加，植物纤维的zeta电位逐渐增大，打浆度逐渐增加；在磨浆转数为20000r时，纤维长度和纤维粗度减小明显，细纤维化程度显著，此时的无石棉胶乳抄取板的抗张指数迟到最大值。因此，植物纤维磨浆转数以20000r左右为宜、此时的打浆度为60°SR．     

混杂纤维对高性能混凝土力学性能与抗渗性能的影响

研究了钢纤维、Dura纤维和Dolanit纤维按二元或三元混杂对大掺量磨细钢渣与膨胀剂复合的高性能水泥基复合材料的力学性能和抗渗性能的影响，从不同尺度与不同性质的纤维在相应结构层次上的叠加效应角度来阐述水泥基复合材料的防渗抗裂机理。     

Removal of trivalent and hexavalent chromium with aminated polyacrylonitrile fibers: performance and mechanisms

Aminated polyacrylonitrile fibers (APANFs) were prepared and used as an adsorbent in a series of batch adsorption experiments for the removal of Cr(III) and Cr(VI) species from aqueous solutions of different pH values. The results show that significant amounts of Cr(III) or Cr(VI) species can be adsorbed by the APANFs, although the adsorption performances was greatly dependent upon the solution pH values. In general, the amounts of adsorption for Cr(III) species increased whereas that for Cr(VI) decreased with the increase of the solution pH values, which suggests that different adsorption mechanisms dominated the removal of Cr(III) or Cr(VI) species on the APANFs. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy revealed that the adsorption of Cr(III) species on the APANFs was largely attributed to the formation of surface complexes between the nitrogen atoms on the APANFs and the Cr(III) species adsorbed, but the adsorption of Cr(VI) species on the APANFs was more likely effected through the formation of hydrogen bonds at high solution pH values or through both electrostatic attraction and surface complexation at low solution pH values. It was found that the Cr(VI)-adsorbed APANFs can be effectively regenerated in a basic solution and be reused almost without any loss of the adsorption capacity, while the Cr(III)-adsorbed APANFs needed to be regenerated in an acidic solution and the regeneration appeared to be less effective.     

Retraining local and global buckling behavior of steel plastic hinges using CFRP

Carbon fiber-reinforced polymer (CFRP) composites have been shown to be particularly well suited for external strengthening of reinforced concrete members. However, there is limited information about how they can be used to strengthen steel structures that are susceptible to local and global instabilities. This paper discusses test results of full-scale steel flexural specimens subjected to reversed cyclic loading, some of which are wrapped with CFRP in the plastic hinge region. The main variables investigated are lateral bracing, to study the effect of CFRP wrapping on local buckling and lateral torsional buckling, wrapping scheme, and number of layers of fibers. The test results show that application of CFRP in the plastic hinge region of flexural members has substantial benefits. In particular, the CFRP wraps can increase the size of the yielded plastic hinge region, slow down the occurrence of local buckling, and delay lateral torsional buckling. These benefits reduce strain demands in the critical plastic hinge region and substantially improve energy dissipation capacity within the plastic hinge region.     

抗裂纤维加固泥岩泥化物固化体试验研究

针对某矿区掘进巷道的底板泥岩泥化物,研制了一种高效固化剂,将该固化剂和聚丙烯抗裂纤维用于泥岩泥化物的加固工程中.通过正交试验,研究了纤维固化体的抗压强度、弹性模量、破坏应变与纤维固化体配比之间的关系.研究表明,泥岩泥化物纤维固化体具有较好的强度与抗变形特性,可作为巷道路面的基层材料.