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
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
Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out...Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.展开更多
Design of forming dies and whole process of simulation of cold rolling involutes spline can be realized by using of CAD software of PRO-E and CAE software of DEFORM-3D. Software DEFORM-3D provides an automatic and opt...Design of forming dies and whole process of simulation of cold rolling involutes spline can be realized by using of CAD software of PRO-E and CAE software of DEFORM-3D. Software DEFORM-3D provides an automatic and optimized remeshing function, especially for the large deformation. In order to use this function sufficiently, simulation of cold rolling involutes spline can be implemented indirectly. The relationship between die and workpiece, forming force and characteristic of deformation in the forming process of cold rolling involutes spline are analyzed and researched. Meanwhile, reliable proofs for the design of dies and deforming equipment are provided.展开更多
In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic （where mastic is a kind of fine mixture composed of asphalt binder mixed with fi...In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic （where mastic is a kind of fine mixture composed of asphalt binder mixed with fines and fine aggregates） and air voids, based on three-dimensional （3D） heterogeneous specimen, X-ray computerized tomography （X-ray CT） was used to scan the asphalt specimens to obtain the real internal microstrnctures of asphalt mixture. CT images were reconstructed to build up 3D digital specimen, and the viscoelastic properties of mastic were described with Burgers model The uniaxial creep numerical simulations of three different levels of aggregate gradation were conducted. The simulation results agree well with the experimental results. The numerical simulation of asphalt mixture incorporated with real 3D microstructure based on finite element method is a promising application to conduct research of asphalt concrete. Additionally, this method can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking the real 3D microstructure.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Project (50490272) supported by the National Natural Science Foundation of China project(NCET-05-0687) supportedby Programfor New Century Excellent Talents project (040109) supported bythe Doctor Degree Paper Innovation Engineering of CentralSouth University
文摘Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.
文摘Design of forming dies and whole process of simulation of cold rolling involutes spline can be realized by using of CAD software of PRO-E and CAE software of DEFORM-3D. Software DEFORM-3D provides an automatic and optimized remeshing function, especially for the large deformation. In order to use this function sufficiently, simulation of cold rolling involutes spline can be implemented indirectly. The relationship between die and workpiece, forming force and characteristic of deformation in the forming process of cold rolling involutes spline are analyzed and researched. Meanwhile, reliable proofs for the design of dies and deforming equipment are provided.
基金Project(51038004) supported by the National Natural Science Foundation of China
文摘In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic （where mastic is a kind of fine mixture composed of asphalt binder mixed with fines and fine aggregates） and air voids, based on three-dimensional （3D） heterogeneous specimen, X-ray computerized tomography （X-ray CT） was used to scan the asphalt specimens to obtain the real internal microstrnctures of asphalt mixture. CT images were reconstructed to build up 3D digital specimen, and the viscoelastic properties of mastic were described with Burgers model The uniaxial creep numerical simulations of three different levels of aggregate gradation were conducted. The simulation results agree well with the experimental results. The numerical simulation of asphalt mixture incorporated with real 3D microstructure based on finite element method is a promising application to conduct research of asphalt concrete. Additionally, this method can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking the real 3D microstructure.
