安徽工业大学材料科学与工程学院, 马鞍山 243002
以矿渣微粉为主要原料, 硅酸钠和氢氧化钠混合溶液为碱性激发剂, 铝粉为发泡剂, 制备地质聚合物基轻质多孔材料, 系统研究了发泡剂、水灰比以及萘系减水剂对材料孔结构与物理性能的影响。结果表明, Al粉在碱性激发剂作用下快速反应生成H2, 促使地质聚合物浆体泡沫化形成多孔材料, 且材料的干密度和抗压强度随Al粉掺量的增加迅速降低。当Al粉掺量超过0.40%(质量分数, 下同), 泡孔急剧增大, 导致泡孔聚并, 强度显著降低。提升水灰比可降低泡孔生长阻力, 促使密度快速减小。但水灰比＞0.40后, 浆体黏度和激发剂浓度显著降低, 凝结时间延长, 孔径增大, 结构劣化, 其最优水灰比为0.35。此外, 萘系减水剂可有效调节多孔地质聚合物的孔结构, 仅添加0.4%的萘系减水剂即可促使孔径分布均一, 孔壁完整性提升, 试样抗压强度提升。
地质聚合物 多孔材料 矿渣微粉 孔结构 力学性能 萘系减水剂 geopolymer porous material slag micronized powder pore structure mechanical property naphthalene water reducer
Author Affiliations
Abstract
1 State Key Laboratory of Precision Measurement Technology & Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
2 Department of Physics, 366 Le Conte Hall MS 7300, University of California, Berkeley, California 94720, USA
Resolution and bandwidth are critical for cavity-enhanced dual-comb spectroscopy (CE-DCS). Here, we pioneer an adaptive approach in CE-DCS to improve the broadband as well as the resolution. Postcorrections to dual-comb interferograms adaptively compensate the relative phase jitters of the optical frequency combs and result in both a mode-resolved spectral resolution and a signal-to-noise ratio of 440:1 in 1 s. Meanwhile, an adaptive comb-cavity locking scheme exploits more than 90% of the comb modes, covering (10 THz) at . For a single dual-comb interferogram, more than 40,000 comb teeth spaced by 250 MHz are measured in less than 7.5 ms, contributing to a noise equivalent absorption per spectral element of . This adaptive cavity-enhanced dual-comb spectroscopy technique provides an attractive spectroscopic tool that may be utilized in trace-gas sensing, breath and cancer analysis, and engine combustion diagnosis.
Photonics Research
2019, 7(8): 08000883
1 宁波大红鹰学院机械与电气工程学院, 浙江 宁波 315175
2 南京理工大学电子工程与光电技术学院, 江苏 南京 210094
提出了基于运动纹理差异的运动目标分割无监督评价方法。通过基于贝叶斯决策的精确量化准则得到差分图像的类别映射图, 利用区域生长方法产生不同效果的运动目标分割掩膜, 定义了运动纹理差异的评价准则, 并将该评价准则用于这些分割掩膜中以验证评价结果的有效性。为进一步准确衡量所提出准则的性能, 在实验中将其与两种评价准则进行对比, 一是有监督评价准则 ME, 二是基于彩色纹理的无监督评价方法 JSEG中的无监督评价准则 J。实验结果证明基于运动纹理差异的无监督评价与人类主观感知和客观实际基本一致, 可有效地对红外视频运动目标分割性能进行无监督评价。
运动纹理差异 无监督评价 分割掩膜 红外视频 motion texture difference unsupervised evaluation segmentation mask infrared video
