为了探索不同径厚比海底管道的压溃屈曲特性,本文分别采用挪威船级社(Det Norske Veritas,DNV)规范、有限元模拟和深海压力舱模型试验,研究不同径厚比海底管道承载外部水压的能力,并就DNV规范压溃屈曲计算公式对不同径厚比管道的适用性...为了探索不同径厚比海底管道的压溃屈曲特性,本文分别采用挪威船级社(Det Norske Veritas,DNV)规范、有限元模拟和深海压力舱模型试验,研究不同径厚比海底管道承载外部水压的能力,并就DNV规范压溃屈曲计算公式对不同径厚比管道的适用性进行了讨论,优化了小径厚比海底管道压溃屈曲的设计方法。研究表明:小径厚比管道的压溃屈曲临界压力对管道径厚比的变化更敏感;DNV规范计算小径厚比管道的压溃屈曲临界压力偏小,在进行深海管道的压溃屈曲设计时,建议采用模型试验结合有限元模拟的方法,计算管道实际可提供的压溃屈曲承载力。展开更多
基于Web of Science和CNKI数据源,分别选取2001—2020年收录的智能制造相关文献作为研究对象,利用CiteSpace可视化软件,对智能制造研究总体现状、研究热点及发展脉络进行了系统梳理与分析。研究发现:近年来智能制造研究受到学者们的高...基于Web of Science和CNKI数据源,分别选取2001—2020年收录的智能制造相关文献作为研究对象,利用CiteSpace可视化软件,对智能制造研究总体现状、研究热点及发展脉络进行了系统梳理与分析。研究发现:近年来智能制造研究受到学者们的高度重视,文献数量呈爆发式增长;研究主题具有鲜明的时代特征,WOS与CNKI数据库中,智能制造领域研究热点在理论与实证研究等多方面存在差异。对智能制造研究的前沿趋势进行分析,并提出未来可能的4个主要方向。展开更多
为了直观地了解人工智能领域发展现状及研究前沿,剖析国内外研究存在的异同点,助力国内人工智能研究。以Web of Science数据库和CNKI数据库的2008—2019年期刊论文为依据,借助Citespace软件对期刊论文进行科学知识图谱绘制和可视化分析...为了直观地了解人工智能领域发展现状及研究前沿,剖析国内外研究存在的异同点,助力国内人工智能研究。以Web of Science数据库和CNKI数据库的2008—2019年期刊论文为依据,借助Citespace软件对期刊论文进行科学知识图谱绘制和可视化分析。根据客观数据和科学知识图谱发现:2016年后,人工智能领域迎来新的研究热潮,且呈现"中美双雄"的格局;在发文质量上,北美区域是当前人工智能研究水平最高的区域;目前,人工智能研究的主力军是高校,且尚未形成产学研相结合的体系;研究主题具有鲜明的时代特征,人工神经网络、算法、大数据、机器人、计算机视觉、法律伦理学等成为当下的研究热点;最后根据人工智能研究脉络演进图与高频突现词提出该领域的"深度强化学习""人工智能+""智能社会科学"三个研究前沿,为后续人工智能研究提供方向建议。展开更多
A facile modification strategy is developed to promote the proliferation and osteogenic differentiation of rat bone marrow stromal cells(rBMSCs)through deposition of a bioactive calcium silicate(CS)coating on the poro...A facile modification strategy is developed to promote the proliferation and osteogenic differentiation of rat bone marrow stromal cells(rBMSCs)through deposition of a bioactive calcium silicate(CS)coating on the porous surface of poly(ether-ether-ketone)(PEEK)with the assistance of poly(dopamine)(PDA).The porous structures are etched on the surface of PEEK after sulfonation treatment.A poly(dopamine)layer is coated on the porous surface of the sulfonated PEEK(SPEEK),which provides anchoring groups for the subsequent deposition of the CS layer.Results show that the CS coating on the porous surface of SPEEK significantly improve the hydrophilicity and biomineralization formation of hydroxyapatite.Compared with PEEK,SPEEK-PDA-CS displays higher bioactivity to promote the proliferation and osteogenic differentiation of rBMSCs,including the increase of ALP activity and formation of calcium nodules,the expression of osteogenic differentiation-related genes.These results are beneficial to extending clinical applications of PEEK-based implants for bone tissue repair and orthopedic surgery.展开更多
The system of SiO2-CaO-P2O5 bioactive glasses （BG） were successfully synthesized by microemulsion approach. X-ray diffraction （XRD）,scanning electron micro scopy（SEM） and energy dispersive X-ray （EDX） analyses...The system of SiO2-CaO-P2O5 bioactive glasses （BG） were successfully synthesized by microemulsion approach. X-ray diffraction （XRD）,scanning electron micro scopy（SEM） and energy dispersive X-ray （EDX） analyses, transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy （FTIR）, BET N2 gas adsorption analysis techniques were utilized in order to evaluate the phase composition, dimension, morphology, interconnectivity of pores and particle size of the synthesized BG respectiveely. The biocompatibility of BG was assessed by using dimethylthiazol diphenyl tetrazolium bromide （MTT）.The BG scaffolds were implanted in rabbit mandibles and studied histologically.The results showed that the BG with a particle size less than 100 nm was prepared successfully. The measured BET specific surface area and pore volume was 113.9 m2/g and 0.28 cm3/g respectively. Cell cultures revealed that BG has been shown to have good biocompatibility and is also beneficial to the survival of Schwann cells, which can promote cell proliferation in vivo assay indicating that the BG can promote osteoconductivity.展开更多
Nd^(3+)-doped NaGdF_(4):Yb,Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method,and the effects of doping concentrations on the crystal structure,phase composition,and upconver...Nd^(3+)-doped NaGdF_(4):Yb,Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method,and the effects of doping concentrations on the crystal structure,phase composition,and upconverted fluorescence intensity were also investigated.The results reveal that the introduction of Nd^(3+) ions does not cause the transformation of the crystal phase,but induce the change of the unit cell parameters.Meanwhile,the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol%Nd^(3+) is the strongest under the excitation of 980 nm laser,which is 3.9 times that of the Nd^(3+)-free doped nanoparticles,and the average size is 62.9 nm.And it is located in the blue area of the CIE coordinate diagram,and the corresponding color purity is 91.81%under the same experimental conditions.The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.展开更多
文摘为了探索不同径厚比海底管道的压溃屈曲特性,本文分别采用挪威船级社(Det Norske Veritas,DNV)规范、有限元模拟和深海压力舱模型试验,研究不同径厚比海底管道承载外部水压的能力,并就DNV规范压溃屈曲计算公式对不同径厚比管道的适用性进行了讨论,优化了小径厚比海底管道压溃屈曲的设计方法。研究表明:小径厚比管道的压溃屈曲临界压力对管道径厚比的变化更敏感;DNV规范计算小径厚比管道的压溃屈曲临界压力偏小,在进行深海管道的压溃屈曲设计时,建议采用模型试验结合有限元模拟的方法,计算管道实际可提供的压溃屈曲承载力。
文摘基于Web of Science和CNKI数据源,分别选取2001—2020年收录的智能制造相关文献作为研究对象,利用CiteSpace可视化软件,对智能制造研究总体现状、研究热点及发展脉络进行了系统梳理与分析。研究发现:近年来智能制造研究受到学者们的高度重视,文献数量呈爆发式增长;研究主题具有鲜明的时代特征,WOS与CNKI数据库中,智能制造领域研究热点在理论与实证研究等多方面存在差异。对智能制造研究的前沿趋势进行分析,并提出未来可能的4个主要方向。
文摘为了直观地了解人工智能领域发展现状及研究前沿,剖析国内外研究存在的异同点,助力国内人工智能研究。以Web of Science数据库和CNKI数据库的2008—2019年期刊论文为依据,借助Citespace软件对期刊论文进行科学知识图谱绘制和可视化分析。根据客观数据和科学知识图谱发现:2016年后,人工智能领域迎来新的研究热潮,且呈现"中美双雄"的格局;在发文质量上,北美区域是当前人工智能研究水平最高的区域;目前,人工智能研究的主力军是高校,且尚未形成产学研相结合的体系;研究主题具有鲜明的时代特征,人工神经网络、算法、大数据、机器人、计算机视觉、法律伦理学等成为当下的研究热点;最后根据人工智能研究脉络演进图与高频突现词提出该领域的"深度强化学习""人工智能+""智能社会科学"三个研究前沿,为后续人工智能研究提供方向建议。
基金Supported by the National Key Research&Development Program of China(No.2018YFB1105702)。
文摘A facile modification strategy is developed to promote the proliferation and osteogenic differentiation of rat bone marrow stromal cells(rBMSCs)through deposition of a bioactive calcium silicate(CS)coating on the porous surface of poly(ether-ether-ketone)(PEEK)with the assistance of poly(dopamine)(PDA).The porous structures are etched on the surface of PEEK after sulfonation treatment.A poly(dopamine)layer is coated on the porous surface of the sulfonated PEEK(SPEEK),which provides anchoring groups for the subsequent deposition of the CS layer.Results show that the CS coating on the porous surface of SPEEK significantly improve the hydrophilicity and biomineralization formation of hydroxyapatite.Compared with PEEK,SPEEK-PDA-CS displays higher bioactivity to promote the proliferation and osteogenic differentiation of rBMSCs,including the increase of ALP activity and formation of calcium nodules,the expression of osteogenic differentiation-related genes.These results are beneficial to extending clinical applications of PEEK-based implants for bone tissue repair and orthopedic surgery.
基金Funded by Guangdong Science and Technology Tackling Project(No.2010B031100002)the Orientation of Lu'an Commissioned the West Anhui University Municipal Research Project(No.2011LW009)
文摘The system of SiO2-CaO-P2O5 bioactive glasses （BG） were successfully synthesized by microemulsion approach. X-ray diffraction （XRD）,scanning electron micro scopy（SEM） and energy dispersive X-ray （EDX） analyses, transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy （FTIR）, BET N2 gas adsorption analysis techniques were utilized in order to evaluate the phase composition, dimension, morphology, interconnectivity of pores and particle size of the synthesized BG respectiveely. The biocompatibility of BG was assessed by using dimethylthiazol diphenyl tetrazolium bromide （MTT）.The BG scaffolds were implanted in rabbit mandibles and studied histologically.The results showed that the BG with a particle size less than 100 nm was prepared successfully. The measured BET specific surface area and pore volume was 113.9 m2/g and 0.28 cm3/g respectively. Cell cultures revealed that BG has been shown to have good biocompatibility and is also beneficial to the survival of Schwann cells, which can promote cell proliferation in vivo assay indicating that the BG can promote osteoconductivity.
文摘Nd^(3+)-doped NaGdF_(4):Yb,Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method,and the effects of doping concentrations on the crystal structure,phase composition,and upconverted fluorescence intensity were also investigated.The results reveal that the introduction of Nd^(3+) ions does not cause the transformation of the crystal phase,but induce the change of the unit cell parameters.Meanwhile,the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol%Nd^(3+) is the strongest under the excitation of 980 nm laser,which is 3.9 times that of the Nd^(3+)-free doped nanoparticles,and the average size is 62.9 nm.And it is located in the blue area of the CIE coordinate diagram,and the corresponding color purity is 91.81%under the same experimental conditions.The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.
