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101.
102.
《Carbon》2015
A micro-supercapacitor with a three-dimensional configuration has been fabricated using an inductively coupled plasma etching technique. A ruthenium oxide–carbon nanotube (CNT) composite with a ripple-like morphology is successfully synthesized using a cathodic deposition technique while using silica-based three-dimensional microstructures as a template. The desired network of carbon nanotubes in the composite facilitates electrolyte penetration and proton exchange/diffusion. A single three dimensional microelectrode is studied using cyclic voltammetry, and a specific capacitance of 272 mF·cm−2 is observed at 5 mV s−1 in a neutral Na2SO4 solution. The accelerated cycle life is tested at 80 mV s−1, and a satisfactory cyclability is observed. When placed on a chip, the symmetric cell exhibits good supercapacitor properties, the specific capacitance up to 37.23 mF cm−2 and specific power density up to 19.04 mW cm−2 were obtained at 50 mA cm−2. 相似文献
103.
《材料与设计》2015
This paper summarizes the results of an experimental investigation into the bond behavior between recycled aggregate concrete (RAC) and deformed steel rebars, with the main variables being the recycled coarse aggregate replacement ratio (RCAr) and water-to-cement ratio of the concrete mixture. The investigation into splitting cracking strength indicates that the degradation of the bond splitting tensile stress of the cover concrete was affected by not only the roundness of the coarse aggregate particles but also the weak interfacial transition zone (ITZ) between the cement paste and the RCA that has a more porous structure in the ITZ than normal concrete. In this study, a linear relationship between the bond strength and the density of the RCA was found, but the high compressive strength reduced the effects of the parameters. To predict the bond strength of RAC using the main parameters, a multivariable model was developed using nonlinear regression analysis. It can be inferred from this study that the degradation characteristic of the bond strength of RAC can be predicted well, whereas other empirical equations and code provisions are very conservative. 相似文献
104.
《The IES Journal Part A: Civil & Structural Engineering》2013,6(4):265-275
In recent studies, the uniform simplified distribution blast load and numerical simulation have proven to be prevalent in the use of investigating structural components dynamic behaviour during blast events, whilst neglecting the negative phase pressure. This study compares the steel column's response during the total pressure period to that of its response during only the positive stage. Moreover, the real blast pressure has varying values depending on the point distance and explosion incident angle. The real blast load curve was derived by using a specialised program to calculate pressure at different points on the steel column vertical line; and the results were used to compare its impact with the uniform and concentrated cases. Also ABAQUS finite element code was used to check the validity of the single-degree-of-freedom (SDOF) analysis method when the column is subjected to axial and transverse blast loads. The obtained results show the SDOF inability through dynamic reaction calculations. In addition, SDOF has limitations in dealing with dynamic steel response when the axial load ratio was greater than 0.5. Damage prediction methods and equations were introduced through different concepts and the ductility ratio was used to estimate the damage level of 100 kg TNT at 4.5 m stand-off distance. The strain rate effects were included in the material with different scenarios based on the dynamic increase factor. 相似文献
105.
Russian Journal of Nondestructive Testing - In this study, the contact quality of shotcrete-rock structures is studied using the impact-echo method (IE) to detect defects in shotcrete with a... 相似文献
106.
“做中学、做中教”是工程教育改革的重要发展方向之一.任务驱动教学法与项目驱动教学法是指在教学过程中,以学生为中心,以任务或者项目为驱动的教学方式,都是“做中学、做中教”教学理念的具体表现形式.文章以路基工程课程教、学为背景,系统阐述了“任务驱动”和“项目驱动”教学模式相结合的课程教学设计与应用,介绍了教学应用中存在的主要问题. 相似文献
107.
利用大型有限元软件MSC.MARC,对SGS(管片-注浆-土体)模型的冲击瞬态过程进行有限元模型瞬态响应模拟,分别得到了在注浆密实、注浆孔洞和注浆不密实三种工况下冲击响应的时程曲线.并通过FFT变换,分析不同注浆缺陷条件下的冲击响应的频谱特征.结果表明,该模型能够较为准确地模拟出机械波在SGS模型中的传播与反射,不同注浆条件表现出了不同的频谱特征,该结果表明采用冲击法识别盾构注浆缺陷的方法是可行的. 相似文献
108.
109.
110.
《Measurement》2016
In water-supply pipeline leak detection and location, both the leak signals and blurred noises are closely related to the pipeline states and surroundings and most of the conventional noise-cancellation methods have to depend on the empirical parameters of either signals or noises. EMD (Empirical Mode Decomposition) is an adaptive signal decomposition method and is exclusive of base functions. A signal is decomposed into several IMFs (Intrinsic Mode Functions) in EMD, then the noise in a signal can be cancelled through removing uncorrelated IMFs. The existing EMD noise cancellation methods need to know the characteristics of either the wanted signal or the noise for rebuilding the noise-removed signal. However the characteristics of leak signals and noises are not fixed in various pipeline conditions, so the existing EMD noise cancellation methods can’t be directly applied in water-supply pipeline leak detection. This paper proposes an adaptive noise cancellation method based on EMD, in which the IMFs that don’t or less contain the components related to the leak can be removed through the cross-correlation between the IMFs and another signal collected at the either side of a suspect leak. In simulation analysis, the adaptive noise cancellation method can increase the SNRs (Signal to Noise Ratios) of leak signals as high as 16 dB. In processing practical pipeline vibro-acoustic signals, with the proposed method the peak of adaptive time delay estimate of leak signals, which determines the location of a leakage, becomes more distinguished, and thus the error of leakage location is improved. 相似文献