为去除导丝伪影以提高血管内光学相干断层扫描(IVOCT)的图像质量,辅助医师更加准确地诊断心血管疾病,降低误诊及漏诊的概率,针对IVOCT图像结构信息复杂且伪影区域占比大的难点,提出一种采用生成对抗网络(GAN)架构的基于Transformer的结...为去除导丝伪影以提高血管内光学相干断层扫描(IVOCT)的图像质量,辅助医师更加准确地诊断心血管疾病,降低误诊及漏诊的概率,针对IVOCT图像结构信息复杂且伪影区域占比大的难点,提出一种采用生成对抗网络(GAN)架构的基于Transformer的结构强化网络(SETN)。首先,GAN的生成器在提取纹理特征的原始图像(ORI)主干生成网络的基础上,并联了RTV(Relative Total Variation)图像强化生成网络用于获取图像的结构信息;其次,在ORI/RTV图像的伪影区域重建过程中,引入了分别关注时/空间域信息的Transformer编码器,用于捕获IVOCT图像序列的上下文信息以及纹理/结构特征之间的关联性;最后,利用结构特征融合模块将不同层次的结构特征融入ORI主干生成网络的解码阶段,配合判别器完成导丝伪影区域的图像重建。实验结果表明,SETN的导丝伪影去除结果在纹理和结构的重建上均十分优秀。此外,导丝伪影去除后IVOCT图像质量的提高,对于IVOCT图像的易损斑块分割及管腔轮廓线提取任务均具有积极意义。展开更多
The low-cost Fe-Cu,Fe-Ni,and Cu-based high-entropy alloys exhibit a widespread utilization prospect.However,these potential applications have been limited by their low strength.In this study,a novel Fe_(31)Cu_(31)Ni_(...The low-cost Fe-Cu,Fe-Ni,and Cu-based high-entropy alloys exhibit a widespread utilization prospect.However,these potential applications have been limited by their low strength.In this study,a novel Fe_(31)Cu_(31)Ni_(28)Al_(4)Ti_(3)Co_(3) immiscible high-entropy alloy(HEA)was developed.After vacuum arc melting and copper mold suction casting,this HEA exhibits a unique phase separation microstructure,which consists of striped Cu-rich regions and Fe-rich region.Further magnification of the striped Cu-rich region reveals that it is composed of a Cu-rich dot-like phase and a Fe-rich region.The aging alloy is further strengthened by a L1_(2)-Ni_(3)(AlTi)nanoprecipitates,achieving excellent yield strength(1185 MPa)and uniform ductility(~8.8%).The differential distribution of the L1_(2) nanoprecipitate in the striped Cu-rich region and the external Fe-rich region increased the strength difference between these two regions,which increased the strain gradient and thus improved hetero-deformation induced(HDI)hardening.This work provides a new route to improve the HDI hardening of Fe-Cu alloys.展开更多
Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way t...Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.展开更多
文摘为去除导丝伪影以提高血管内光学相干断层扫描(IVOCT)的图像质量,辅助医师更加准确地诊断心血管疾病,降低误诊及漏诊的概率,针对IVOCT图像结构信息复杂且伪影区域占比大的难点,提出一种采用生成对抗网络(GAN)架构的基于Transformer的结构强化网络(SETN)。首先,GAN的生成器在提取纹理特征的原始图像(ORI)主干生成网络的基础上,并联了RTV(Relative Total Variation)图像强化生成网络用于获取图像的结构信息;其次,在ORI/RTV图像的伪影区域重建过程中,引入了分别关注时/空间域信息的Transformer编码器,用于捕获IVOCT图像序列的上下文信息以及纹理/结构特征之间的关联性;最后,利用结构特征融合模块将不同层次的结构特征融入ORI主干生成网络的解码阶段,配合判别器完成导丝伪影区域的图像重建。实验结果表明,SETN的导丝伪影去除结果在纹理和结构的重建上均十分优秀。此外,导丝伪影去除后IVOCT图像质量的提高,对于IVOCT图像的易损斑块分割及管腔轮廓线提取任务均具有积极意义。
基金Projects(52001083,52171111,U2141207)supported by the National Natural Science Foundation of ChinaProject(LH2020E060)supported by the Natural Science Foundation of Heilongjiang,China。
文摘The low-cost Fe-Cu,Fe-Ni,and Cu-based high-entropy alloys exhibit a widespread utilization prospect.However,these potential applications have been limited by their low strength.In this study,a novel Fe_(31)Cu_(31)Ni_(28)Al_(4)Ti_(3)Co_(3) immiscible high-entropy alloy(HEA)was developed.After vacuum arc melting and copper mold suction casting,this HEA exhibits a unique phase separation microstructure,which consists of striped Cu-rich regions and Fe-rich region.Further magnification of the striped Cu-rich region reveals that it is composed of a Cu-rich dot-like phase and a Fe-rich region.The aging alloy is further strengthened by a L1_(2)-Ni_(3)(AlTi)nanoprecipitates,achieving excellent yield strength(1185 MPa)and uniform ductility(~8.8%).The differential distribution of the L1_(2) nanoprecipitate in the striped Cu-rich region and the external Fe-rich region increased the strength difference between these two regions,which increased the strain gradient and thus improved hetero-deformation induced(HDI)hardening.This work provides a new route to improve the HDI hardening of Fe-Cu alloys.
基金Project(2021YFC2902102)supported by the National Key Research and Development Program of ChinaProject(52374142)supported by the National Natural Science Foundation of ChinaProject(JSTU-2022-066)supported by the Young Talent Support Project of Jiangsu Association for Science and Technology,China。
文摘Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.
