浅谈桥涵混凝土表面蜂窝麻面的防治措施

结合福山立交至福山镇公路改建工程混凝土桥涵的施工过程,从多方面分析桥涵混凝土表面产生蜂窝麻面的原因,并提出防治措施,从而避免蜂窝麻面的产生,提高桥涵的外观质量。     

蜂窝夹层结构基板脱粘问题分析

蜂窝夹层结构基板经热真空试验后,其正面局部出现了鼓泡脱粘现象,脱粘形式有2种,一种为聚酰亚胺膜与网格面板脱粘,另一种为网格面板与加强板脱粘。通过对聚酰亚胺膜与网格面板脱粘界面的宏微观观察,确定两者在脱粘前粘接良好,为外力导致的脱粘;通过对网格面板与加强板脱粘界面的宏微观观察,及胶膜的红外光谱分析、DSC测试、挥发分测试,确定网格面板与加强板在脱粘前未形成良好的粘接,该不良粘接可能与设计、工艺控制有关,与胶膜质量无关。     

YT822A型芳纶纸蜂窝性能研究

采用YT822A型芳纶纸和新型酚醛树脂制造了大尺寸蜂窝芯材,研究了YT822A型芳纶纸蜂窝的物理参数、力学性能及阻燃性能,并且与BMS 8-124AB规定的各项性能指标进行了比对。试验结果表明:YT822A型芳纶纸蜂窝芯材具有优异的综合性能,且各项参数和性能均能达到BMS 8-124AB的指标要求,为国产蜂窝芯材走向国际市场开拓了道路。     

Nomex纸蜂窝增强酚醛泡沫的制备及性能研究

本文以自制酚醛树脂发泡制备的酚醛泡沫为基体,Nomex纸蜂窝为增强体,采用特定的发泡制备工艺制得了Nomex纸蜂窝增强酚醛泡沫.通过对该材料微观形貌、力学性能和热性能的表征,初步探讨了材料基体和界面效应对其力学性能和隔热性能的影响.研究结果发现,填充了酚醛泡沫后,Nomex纸蜂窝增强酚醛泡沫的力学性能显著提高,导热系数显著降低.分析认为,良好的强结合界面保障了酚醛泡沫对Nomex纸蜂窝增强酚醛泡沫力学性能和隔热性能的贡献,该材料是一种综合性能较好的隔热、阻燃材料.     

TC4合金蜂窝冰固持低温铣削研究

广泛应用于航天领域的低刚度薄壁钛合金蜂窝材料,在铣削加工中面临卷曲、开焊、塌边等缺陷,需改进其固持和加工方法。材料通过冰固持方法处理,并进行高速深冷铣削加工;分析了蜂窝铣削性能和加工缺陷产生原因,提出了冰固持超低温铣削机理。结果表明,相比于传统固持加工方式,经冰固持低温铣削的钛合金蜂窝表面质量有很大提高,加工缺陷被有效抑制;切削深度对表面质量影响较大。切削参数对铣削力影响顺序:切深最大,可提高约3倍,其次是主轴转速,进给速度影响最小。冰固持低温方法提高了蜂窝强度,实现了超低温切削,改变了断屑方式。结论:冰固持低温切削为面内径向等效强度小、低刚度薄壁钛合金蜂窝材料高效加工提供了新方法。     

GBF蜂巢芯现浇混凝土密肋楼盖的经济分析

介绍了GBF蜂巢芯结构好、重量轻、造价低等特点,结合山东友邦置业有限公司开发的地下车库工程,分析了GBF蜂巢芯现浇混凝土密肋楼盖的设计原理、施工工艺流程及施工操作要点,并着重探讨了该工程采用GBF蜂巢芯现浇混凝土密肋楼盖技术所产生的经济效益。     

Thermo-physical properties of Hastelloy X and Haynes 214 close to the melting range

ABSTRACT

The nickel-based superalloys Hastelloy X and Haynes 214 are widely used for honeycomb liners; however, thermo-physical properties at temperatures close to the melting range are poorly described in the literature. Based on the thermo-physical properties, endothermic effects between 550°C and 650°C have been observed that develop due to the formation of the short-range order in both alloys and in Haynes 214, in addition to the short-range order, an increase in the specific heat capacity due to the γ′-precipitation up to 950° was detected. At low and intermediate temperatures, the Hastelloy X is significantly better suited than the Haynes 214. At high temperatures the Haynes 214 is superior to the Hastelloy X due to the dissolution of the γ′-phase.     

Effect of electrode spacing on the performance of microbial fuel cells with a honeycomb flow straightener

Microbial fuel cells (MFCs) are bioelectrochemical transducers that can be used to produce electrical power under the activity of microbes during the wastewater treatment processes. In the present study, the electrode spacing was considered as a parameter to investigate the influence on the performance of MFCs. The electrode spacing was defined as the distance of the anode electrode plate to the polymer exchange membrane in the MFCs. Three values were set at 0.0, 3.0, and 6.0 cm, respectively. In addition, a flow device, like a honeycomb type flow straightener, was introduced and implemented in the anode chamber for creating a uniform flow. The inner diameter of the honeycomb was 0.7 cm. Results showed that a higher limiting current density with 4108.7 mA/m² and a lower resistance with 2.51 Ω can be found in the case of the 0.0 cm electrode spacing. These results also indicated that the shorter electrode spacing with flow straightener devices would improve the performance of MFCs, leading to lower internal resistance and higher power density. In addition, the scanning electron microscopy was employed to analyze the biofilm thickness for MFCs with different electrode spacing. It was also found that the biofilm thickness with 0 cm electrode spacing was larger than the other two cases, leading to a lower internal resistance in the MFCs.     

Eutectic compound (KNO3/NaNO3 : PCM) quasi‐encapsulated into SiC‐honeycomb for suppressing natural convection of melted PCM

The phase change eutectic compound, KNO₃/NaNO₃ (50/50 mol%) (phase change material (PCM)), which is used as the thermal energy storage material in the solar thermal power plant, was quasi‐encapsulated into the SiC‐honeycomb (SCH) for suppressing the natural convection occurring at the liquid state of PCM. The performance of the SCH as the material suppressing natural convection of PCM was investigated experimentally. PCM with three kinds of mixing ratios of SCH of 10%, 20%, and 30%, was prepared and packed in their respective stainless can with oil‐flowing pipe in the center, which is called thermal energy storage unit (TESU). Three units were linked together and stacked vertically by the connector at the inlet/outlet oil pipe. The time variation of temperature at the fixed positions inside the TESU in charging/discharging process and temperature gradient in the radial direction inside TESU when PCM was liquid state were investigated. It is concluded that the natural convection is suppressed by mixing the SCH with PCM up to around 30% in weight, because the PCM is quasi‐encapsulated into cell holes and porous structures of SCHs. And thus, the heat transfer of the PCM + 30%SCH composite is controlled mainly by its thermal conduction, which is also supported through comparison of simulation result with experimental one. And so, we conclude that SCH has a function as the quasi‐encapsulating material for suppressing the natural convection of PCM. Copyright © 2015 John Wiley & Sons, Ltd.     

堇青石的二氧化硅涂敷实验研究

本文采用不同的酸对蜂窝式堇青石进行处理,研究酸蚀处理对其组成和孔结构的影响。并以自制的二氧化硅溶胶为第二载体对酸处理后的堇青石进行涂敷。采用XRD、N2等温吸附-脱附、SEM等手段对二氧化硅进行表征。结果表明:酸蚀处理并不改变堇青石的晶相结构;经酸处理后的堇青石其比表面积有不同程度的增加;而经二氧化硅涂敷后的堇青石比表面积可达93.35m2/g。