开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿...开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿命,并在模拟自然光下测定了其对盐酸四环素(TC)的光催化降解性能和循环稳定性.结果表明:TiO_(2)前驱体溶胶起到了分散P25颗粒和稳定浆料的作用,而PVA的加入则进一步改善了浆料的流变性能.当使用9 g P25粉末与10 mL TiO_(2)前驱体溶胶和1 mL质量分数为7%的PVA溶液混合时,得到了具有最佳成型性能的打印浆料,制备的降解筛结构完整,无塌陷和开裂.热处理后TiO_(2)前驱体溶胶转化而来的小粒径TiO_(2)填充在P25颗粒之间,起到了增强机械强度的作用,而PVA作为造孔剂极大地丰富了降解筛的孔隙结构.TiO_(2)光催化降解筛对TC表现出优异的光催化性能和循环稳定性,140 min内的降解率为98.4%,并在5次循环之后保持96.0%的降解率.展开更多
The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E ...The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.展开更多
海冰密集度是描述海冰特征的重要参数,准确获取海冰密集度对研究全球气候变化具有重要意义。针对北极夏季海冰密集度反演精度较低的问题,本文通过对微波辐射传输模型中的海冰发射率和初始海冰密集度进行优化估算,改善了微波辐射传输模...海冰密集度是描述海冰特征的重要参数,准确获取海冰密集度对研究全球气候变化具有重要意义。针对北极夏季海冰密集度反演精度较低的问题,本文通过对微波辐射传输模型中的海冰发射率和初始海冰密集度进行优化估算,改善了微波辐射传输模型对夏季观测亮温的大气校正效果,从而优化被动微波海冰密集度的反演结果,本研究采用2019年6—9月的FY-3D/MWRI亮温数据,分别利用优化前和优化后的ASI2算法(ASI2和ASI2E),结合固定系点(FTP)与动态系点(DTP),分别获得了4套夏季北极海冰密集度数据(ASI2-FTP、ASI2-DTP、ASI2E-FTP、ASI2E-DTP),并利用14景MODIS影像对结果进行了精度验证。研究结果表明,本研究提出的优化方法可有效提高北极夏季海冰密集度的反演精度,其中该优化方法对基于固定系点的反演改进尤为明显,其优化后的均方根误差(root mean square error,ERMSE)由21.9%减小到15.43%,偏差(bias,|B_(bias)|)由-12.40%下降到-6.01%。4种反演方法中,基于动态系点的算法优化后(ASI2E-DTP)表现尤为明显,其E_(RMSE)和B_(bias)分别为14.33%和-4.53%。展开更多
文摘开发了一种使用直写成型(DIW)3D打印方法制备多孔TiO_(2)光催化降解筛的成型技术,厘清了打印浆料中P25粉末、TiO_(2)前驱体溶胶和聚乙烯醇(PVA)含量对其成型性能的影响规律;进一步研究了降解筛的物相组成、微观形貌、能带结构和载流子寿命,并在模拟自然光下测定了其对盐酸四环素(TC)的光催化降解性能和循环稳定性.结果表明:TiO_(2)前驱体溶胶起到了分散P25颗粒和稳定浆料的作用,而PVA的加入则进一步改善了浆料的流变性能.当使用9 g P25粉末与10 mL TiO_(2)前驱体溶胶和1 mL质量分数为7%的PVA溶液混合时,得到了具有最佳成型性能的打印浆料,制备的降解筛结构完整,无塌陷和开裂.热处理后TiO_(2)前驱体溶胶转化而来的小粒径TiO_(2)填充在P25颗粒之间,起到了增强机械强度的作用,而PVA作为造孔剂极大地丰富了降解筛的孔隙结构.TiO_(2)光催化降解筛对TC表现出优异的光催化性能和循环稳定性,140 min内的降解率为98.4%,并在5次循环之后保持96.0%的降解率.
文摘The novelty of this research lies in the successful fabrication of a 3D-printed honeycomb structure filled with nanofillers for acoustic properties,utilizing an impedance tube setup in accordance with ASTM standard E 1050-12.The Creality Ender-3,a 3D printer,was used for printing the honeycomb structures,and polylactic acid(PLA)material was employed for their construction.The organic,inorganic,and polymeric compounds within the composites were identified using fourier transformation infrared(FTIR)spectroscopy.The structure and homogeneity of the samples were examined using a field emission scanning electron microscope(FESEM).To determine the sound absorption coefficient of the 3D printed honeycomb structure,numerous samples were systematically developed using central composite design(CCD)and analysed using response surface methodology(RSM).The RSM mathematical model was established to predict the optimum values of each factor and noise reduction coefficient(NRC).The optimum values for an NRC of 0.377 were found to be 1.116 wt% carbon black,1.025 wt% aluminium powder,and 3.151 mm distance between parallel edges.Overall,the results demonstrate that a 3Dprinted honeycomb structure filled with nanofillers is an excellent material that can be utilized in various fields,including defence and aviation,where lightweight and acoustic properties are of great importance.
文摘海冰密集度是描述海冰特征的重要参数,准确获取海冰密集度对研究全球气候变化具有重要意义。针对北极夏季海冰密集度反演精度较低的问题,本文通过对微波辐射传输模型中的海冰发射率和初始海冰密集度进行优化估算,改善了微波辐射传输模型对夏季观测亮温的大气校正效果,从而优化被动微波海冰密集度的反演结果,本研究采用2019年6—9月的FY-3D/MWRI亮温数据,分别利用优化前和优化后的ASI2算法(ASI2和ASI2E),结合固定系点(FTP)与动态系点(DTP),分别获得了4套夏季北极海冰密集度数据(ASI2-FTP、ASI2-DTP、ASI2E-FTP、ASI2E-DTP),并利用14景MODIS影像对结果进行了精度验证。研究结果表明,本研究提出的优化方法可有效提高北极夏季海冰密集度的反演精度,其中该优化方法对基于固定系点的反演改进尤为明显,其优化后的均方根误差(root mean square error,ERMSE)由21.9%减小到15.43%,偏差(bias,|B_(bias)|)由-12.40%下降到-6.01%。4种反演方法中,基于动态系点的算法优化后(ASI2E-DTP)表现尤为明显,其E_(RMSE)和B_(bias)分别为14.33%和-4.53%。
基金Key Project Process Mechanism and Prediction of Geological Hazards (2001CB711005-1-3) and State Key Basic Research Project Mechanism and Prediction of Continental Earthquakes (G1998040702). sponsored by the Ministry of Science and Techno
