The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In...The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.展开更多
Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthe...Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.展开更多
The AEC (Architecture, Engineering, and Construction) industry is gradually shifting away from 2D CAD drawings and toward Building Information Modeling as a result of the fast development of science and technology (BI...The AEC (Architecture, Engineering, and Construction) industry is gradually shifting away from 2D CAD drawings and toward Building Information Modeling as a result of the fast development of science and technology (BIM). The BIM idea’s introduction emphasizes the need to specify a building in a single building model with adequate information to suit its different needs rather than defining it in fragmented documents. This research work aims to use the BIM 4D for the simulation of the construction sequence of a Swivel Bridge. For that, the software Revit was used to make the 3D model of the bridge, and the software Navisworks was used for the 4D construction simulation of the project. The results demonstrated that BIM technology could help reduce delays and problems with the schedule and improve communication among stakeholders, and BIM visualization and simulation features were very useful compared to traditional planning methods.展开更多
目的:通过3D/4D超声鼻唇表面成像,观察胎儿鼻唇部表面形态结构,排除鼻唇部表面异常。方法:使用VOLUSON GE 730及VOLUSON GE E8容积探头,通过对2063例孕22-25周胎儿进行3D/4D鼻唇部表面成像,要求清晰显示鼻尖、鼻柱、鼻翼、双鼻孔、鼻唇...目的:通过3D/4D超声鼻唇表面成像,观察胎儿鼻唇部表面形态结构,排除鼻唇部表面异常。方法:使用VOLUSON GE 730及VOLUSON GE E8容积探头,通过对2063例孕22-25周胎儿进行3D/4D鼻唇部表面成像,要求清晰显示鼻尖、鼻柱、鼻翼、双鼻孔、鼻唇沟、上下唇、下颌,观察胎儿鼻部形状、大小、结构、唇部完整性和连续性。结果:2063例孕22~25周胎儿中,获得清晰完整鼻唇3D/4D表面成像1689例,显示率为81.87%;获取部分鼻唇表面成像306例,显示率为14.83%;模糊或不能成像68例,占3.3%。结论:孕中期大部分胎儿3D/4D超声能获取鼻唇完整清晰表面成像,形象、逼真、直观显示鼻唇表面形态结构正常与否;掌握必要的检查方法、注意事项及技巧能提高鼻唇部清晰完整表面成像显示率。展开更多
Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionall...Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.展开更多
为了能更好地体现隧道开挖的时空效应,表达出隧道内监测点位移或应力随时空的变化情况,便于工程的动态管理与决策,采用Open CASCADE三维几何引擎和Visual Studio 2008开发工具,实现了隧道三维计算机空间模型与施工进度关联在一起的可视...为了能更好地体现隧道开挖的时空效应,表达出隧道内监测点位移或应力随时空的变化情况,便于工程的动态管理与决策,采用Open CASCADE三维几何引擎和Visual Studio 2008开发工具,实现了隧道三维计算机空间模型与施工进度关联在一起的可视化施工顺序表现,即隧道4D可视化监测系统。该系统在重庆轨道交通三号线红旗河沟车站隧道工程中得到了成功应用,它能快速直观地表达出施工工况与监测点的历时数据,从而保证了隧道的施工安全。展开更多
基金Funded by the National Basic Research Program of Chinathe National Natural Science Foundation of China(51675266)+3 种基金the Aeronautical Science Foundation of China(2014ZB52024)the Fundamental Research Funds for the Central Universities(NJ20160038)the Jiangsu Innovation Program for Graduate Education(CXLX13_165)the Fundamental Research Funds for the Central Universities
文摘The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.
基金supported by the National Natural Science Foundation of China(No.22071045)the Excellent Youth Science Fund Project of Henan Province(No.202300410042)+2 种基金the Natural Science Foundation of Henan Province(No.232300420372)Henan Universitythe State Key Laboratory of Physical Chemistry of the Solid Surface of Xiamen University。
文摘Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.
文摘The AEC (Architecture, Engineering, and Construction) industry is gradually shifting away from 2D CAD drawings and toward Building Information Modeling as a result of the fast development of science and technology (BIM). The BIM idea’s introduction emphasizes the need to specify a building in a single building model with adequate information to suit its different needs rather than defining it in fragmented documents. This research work aims to use the BIM 4D for the simulation of the construction sequence of a Swivel Bridge. For that, the software Revit was used to make the 3D model of the bridge, and the software Navisworks was used for the 4D construction simulation of the project. The results demonstrated that BIM technology could help reduce delays and problems with the schedule and improve communication among stakeholders, and BIM visualization and simulation features were very useful compared to traditional planning methods.
文摘目的:通过3D/4D超声鼻唇表面成像,观察胎儿鼻唇部表面形态结构,排除鼻唇部表面异常。方法:使用VOLUSON GE 730及VOLUSON GE E8容积探头,通过对2063例孕22-25周胎儿进行3D/4D鼻唇部表面成像,要求清晰显示鼻尖、鼻柱、鼻翼、双鼻孔、鼻唇沟、上下唇、下颌,观察胎儿鼻部形状、大小、结构、唇部完整性和连续性。结果:2063例孕22~25周胎儿中,获得清晰完整鼻唇3D/4D表面成像1689例,显示率为81.87%;获取部分鼻唇表面成像306例,显示率为14.83%;模糊或不能成像68例,占3.3%。结论:孕中期大部分胎儿3D/4D超声能获取鼻唇完整清晰表面成像,形象、逼真、直观显示鼻唇表面形态结构正常与否;掌握必要的检查方法、注意事项及技巧能提高鼻唇部清晰完整表面成像显示率。
文摘Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.
文摘为了能更好地体现隧道开挖的时空效应,表达出隧道内监测点位移或应力随时空的变化情况,便于工程的动态管理与决策,采用Open CASCADE三维几何引擎和Visual Studio 2008开发工具,实现了隧道三维计算机空间模型与施工进度关联在一起的可视化施工顺序表现,即隧道4D可视化监测系统。该系统在重庆轨道交通三号线红旗河沟车站隧道工程中得到了成功应用,它能快速直观地表达出施工工况与监测点的历时数据,从而保证了隧道的施工安全。
