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通过对坭兴陶原始坯料进行不同的工艺处理,研究降低坭兴陶烧成温度的工艺条件.结果表明:采用氧化铝瓷球来球磨原始坯料,可降低坭兴陶的烧成温度达60℃,并且烧成温度范围可由原来的40℃度拓宽到1 00℃,另一种除砂工艺也可以提高原料的细度,降低烧成温度,拓宽烧成范围,但工序较复杂,相比较而言,球磨工艺效率更高,更适合工业生产. 相似文献
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Self-compacting concrete (SCC) was used for the filling layer of CRTSIII plate ballastless track, which needs excellent workability. The rheological properties of SCC cement paste containing chemical admixtures (CA) such as polycarboxylate-based superplasticizer (PCE), air-entraining agent (AE) and defoamer (DF) were investigated using a Brookfield R/S SST2000 soft solid tester with a vane geometry spindle. The cementitious materials were designed as one, two and, three components systems by addition of ordinary portland cement (OPC) with these chemical admixtures. The rheological properties of one-component system (PCE paste) were improved with increasing the content of PCE. For two components systems of PCE-AE and PCE-DF, yield stress and plastic viscosity reduced firstly and increased afterward with the increasing of AE content. And the plastic viscosity reached the optimum when the content of AE is 0.004wt%. In general, the trend of yield stress and plastic viscosity decreased with the increasing of the DF content. For three components systems, PCE-AE-DF systems, the rheological properties were improved compared with the sample with AE or DF, which attributed to mixes of the active components mentioned above (CA) which could have a synergetic effect. 相似文献
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对庄浪河中上游的输沙资料进行了分析研究,庄浪河流域中上游的年输沙量年内分配极不均匀,而且这种不均匀的状态多年来相对稳定。人类活动对该流域输沙量年内分配的影响较小,对流域年输沙量变化的影响不明显。流域内的植被环境尚好,水土流失态势稳定。 相似文献
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快速成像的磁共振(MR)图象通常信噪比较低,并且在其幅值重建图象中噪声与信号密切相关,呈Rician分布.本文针对MR图象噪声特点,提出了一种基于小波多尺度变换的MR图象自适应去噪算法.该算法在去噪之前,利用小波多尺度快速变换,将与噪声和边缘相关的系数在每一个尺度分别进行建模,获得各自以及整体的概率分布公式,并采用最大似然估计求出相应参数值.然后运用Bayes后验概率公式,获取相应萎缩函数,在此基础上进一步结合边缘系数和噪声系数在空间与尺度连续性方面的特点,对萎缩函数加以改进,使之能更好的区分边缘点和噪声点.试验结果显示,该方法充分考虑了MR图象噪声分布的特点,能够有效去除噪声,保存边缘,提高信噪比,是一种比较有效的方法. 相似文献
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采用正交试验方法进行设计配制椰壳纤维再生混凝土,选择了配制椰壳纤维再生混凝土抗折强度的最优配合比,和未掺加椰壳纤维的基准混凝土进行比较。建立了抗折强度逐步回归分析方程,并对破坏后的混凝土进行微观分析。试验结果表明,在再生骨料取代量、粉煤灰取代量、椰壳纤维掺量和水胶比、高效减水剂五个影响因素中,对再生混凝土28 d抗折强度的影响最主要的影响因素是水胶比。再生混凝土的抗折强度比基准混凝土提高较多;所建立的逐步回归分析方程精度高,R=0.917,可用于拟合预报再生混凝土的抗折强度。通过微观分析,发现再生混凝土和椰壳纤维结合紧密,抗折强度提高显著。经正交试验确定的最佳配合比设计的再生混凝土和易性和强度均能满足一般工程要求。 相似文献