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Fine debris flows formed by the Orientale basin

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Earth and Planetary Physics 2020年第3期4卷 212-222页

作者： YuZhen Cai zhiyong xiao ChunYu Ding Jun Cui Planetary Environmental and Astrobiological Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhaiGuangdong 519000China State Key Laboratory of Lunar and Planetary Sciences Space Science InstituteMacao University of Science and TechnologyMacao 999078China Center for Excellence in Comparative Planetology Chinese Academy of ScienceHefei 230026China Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

The prototype for investigations of formation mechanisms and related geological effects of large impact basins on planetary bodies has been the Orientale basin on the Moon.Its widespread secondaries,light plains,and near-rim melt flows have been well mapped in previous studies.Flow features are also widely associated with secondaries on planetary bodies,but their physical properties are not well constrained.The nature of flow features associated with large impact basins are critically important to understand the emplacement process of basin ejecta,which is one of the most fundamental processes in shaping the shallow crusts of planetary bodies.Here we use multisource remote sensing data to constrain the physical properties of flow features formed by the secondaries of the Orientale basin.The results suggest that such flows are dominated by centimeter-scale fine debris fines;larger boulders are not abundant.The shattering of target materials during the excavation of the Orientale basin,landing impact of ejecta that formed the secondaries,and grain comminution within the flows have substantially reduced particle sizes,forming the fine flows.The discovery of global-wide fine debris flows formed by large impact basins has profound implications to the interpretation of both previously-returned samples and remote sensing data.

关键词： Moon Orientale impact craters impact cratering ejecta

Reveal the pharmacodynamic substances and mechanism of an edible medicinal plant Rhodiola crenulate in DSS-induced colitis through plasma pharmacochemistry and metabolomics

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Food Science and Human Wellness 2024年第4期13卷 2116-2131页

作者： Yu Peng xiaoao xiao Tingting Ji Xinyuan Wang Yixuan Xu Jianbo xiao Hui Cao zhiyong Chen Huifan Liu Yuanqing Gao Hongxun Tao Key Laboratory of Cardiovascular and Cerebrovascular Medicine School of PharmacyNanjing Medical UniversityNanjing 211166China School of Food and Biological Engineering Jiangsu UniversityZhenjiang 212013China Department of Analytical Chemistry and Food Science Faculty of ScienceUniversity of VigoVigo 36310Spain CISPAC Fontan BuildingCity of CultureSantiago de Compostela 15707Spain Shaanxi Academy of Traditional Chinese Medicine Xi'an 710003China Guangdong Key Laboratory of Science and Technology of Lingnan Specialty Food Zhongkai University of Agriculture and EngineeringGuangzhou 510550China State Key Laboratory of Southwestern Chinese Medicine Resources Chengdu 610075China

Rhodiola crenulate is the edible medicinal herbal medicine widely used for altitude sickness in China.Interestingly,our previous work has found that R.crenulate extract(RCE)could significantly improve the pathology associated with dextran sulfate sodium-induced colitis.Thus,the current research aims to reveal the pharmacodynamic material basis of RCE,as well as its mechanism against colitis.The chemical characterization of RCE was performed by UHPLC-HR-MS,through which a total of 88 constituents were identified.Meanwhile,our results also found 29 constituents absorbed into blood and 8 metabolized absorbable compounds.The decreased flavonoids prototype and the elevated sulfated products of phenols were observed under pathophysiological conditions of colitis.The metabolomics study revealed that colitis caused the alternation of fatty acid metabolism,steroid hormone biosynthesis and bile acid metabolism.Correspondingly,RCE could prevent colitis by improving fatty acid metabolism and secondary bile acid metabolism.

关键词： Rhodiola crenulate Colitis Chemical characterization Plasma pharmacochemistry Metabolomics

Microstructure Control of Nanoporous Silica Thin Film Prepared by Sol-gel Process

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Journal of Materials Science & Technology 2007年第4期23卷 504-508页

作者： Yiqun xiao Jun SHEN zhiyong XIE Bin ZHOU Guangming WU Pohl Institute of Solid State Physics Tongji University Shanghai 200092 China

Nanoporous silica films were prepared by sol-gel process with base, acid and base/acid two-step catalysis.Transmission electron microscope （TEM） and particle size analyzer were used to characterize the microstructure and the particle size distribution of the sols. Scanning electron microscopy （SEM）, atomic force microscopy （AFM） and spectroscopic ellipsometer were used to characterize the surface microstructure and the optical properties of the silica films. Stability of the sols during long-term storage was investigated. Moreover,the dispersion relation of the optical constants of the silica films, and the control of the microstructure and properties of the films by changing the catalysis conditions during sol-gel process were also discussed.

关键词： Sol-gel Nanoporous Microstructure Optical constants Silica Thin Film

An updated constraint on the local stratigraphy at the Chang'E-4 landing site

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Earth and Planetary Physics 2021年第1期5卷 19-31页

作者： YiRen Chang zhiyong xiao YiChen Wang ChunYu Ding Jun Cui YuZhen Cai State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhaiGuangdong 519000China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230000China National Astronomical Observations of China Chinese Academy of SciencesBeijing 100000China

The Chang’E-4 mission has been exploring the lunar farside.Two scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface processes at the lunar farside.Publications to date that are based on the reflectance spectra and radar data obtained by the rover have shown a persistent inconsistency about the local stratigraphy.To explain both the abnormal surface topography at the landing site and the unexpected radargram observed by the rover,the Alder crater has been frequently reported to be older than the mare basalts at that landing site.However,this argument is not supported by earlier geological mapping nor recent crater statistics.Resolving this controversy is critical for a full understanding of the geological history of the landing area and for correct interpretations of the scientific data returned.Employing detailed crater statistics,rigorous statistical analyses,and an updated crater chronology function,this study is determined to resolve the relative ages of the Alder crater,Finsen crater,and the mare basalts on the floor of Von Kármán.Our results reveal that while background secondaries and local resurfacing have widely occurred in the study area,affecting age determinations,the statistics are significant enough to conclude that the Alder crater is the oldest among the three targets.This independent constraint is consistent with both the crosscutting relationships of different terrains in this area and global stratigraphic mapping.Our results exclude Alder as a possible contributor of the post-mare deposits at the landing site,appealing for a more systematic stratigraphy study to resolve the provenances of these deposits.

关键词： Moon Chang'E-4 impact craters absolute model age stratigraphy

Formation mechanism of the Lidang circular structure in the Guangxi Province

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Earth and Planetary Physics 2019年第4期3卷 298-304页

作者： Pan Yan zhiyong xiao YiZhen Ma YiChen Wang Jiang Pu Planetary Science Institute School of Earth Sciences China University of Geosciences (Wuhan) Wuhan 430074 China 2State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and Technology Macao 999078 China Chinese Academy of Sciences Center for Excellence in Comparative Planetology Beijing 100864 China

The Lidang circular structure in the center of the Guangxi Province is about 8 km in diameter. This structure appears as an abnormal shallow depression that has disturbed the rather harmonic regional joint systems. Its unique occurrence in the whole region, the circular morphology, negative topography, and the spatial distribution of interior and exterior strata are all consistent with those of impact craters that are formed by asteroidal or cometary collision. To test the impact hypothesis, we carried out both field investigation and remote sensing study of this structure. Regional geological history suggests that if the impact hypothesis were correct, the impact event should have occurred at or after the Early Permian. Field investigation found that the strata inside and outside the crater are dominated by parallel stacks of Lower and Upper Permian limestone that have various thicknesses and different mud contents. The layers of limestone within and outside the circular structure have identical attitudes;no structural disturbances were visible in the outcrops. Field investigations provide conclusive evidence against the impact cratering hypothesis. A high-resolution digital elevation model shows that the spatial distribution of rounded mountains within the structure is controlled by faint but continual extension of joints, suggesting that the crater interior has gone through a much higher degree of erosion. Therefore, regional joints that had once existed within the crater are preserved less well than exterior terrains, forming the abruptly disrupted circular depression. Differential erosion, as the possible formation mechanism of the Lidang structure, is consistent with the different mud contents found between the interior and exterior limestone. The circular outline of this structure may correspond to the shape of the original deposition basin. In conclusion, the Lidang circular structure is a polje formed by karstification, not an astrobleme.

关键词： impact crater impact cratering geomorphology karst Guangxi

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双重编—解码架构的肠胃镜图像息肉分割

中国图象图形学报 2022年第12期27卷 3637-3650页

作者：魏天琦肖志勇江南大学人工智能与计算机学院无锡214122

目的肠胃镜诊断一直被认为是检测及预防结直肠癌的金标准,但当前的临床检查中仍存在一定的漏诊概率,基于深度学习的肠胃内窥镜分割方法可以帮助医生准确评估癌前病变,对诊断和干预治疗都有积极作用。然而提高目标分割的准确性仍然是一... 详细信息

目的肠胃镜诊断一直被认为是检测及预防结直肠癌的金标准,但当前的临床检查中仍存在一定的漏诊概率,基于深度学习的肠胃内窥镜分割方法可以帮助医生准确评估癌前病变,对诊断和干预治疗都有积极作用。然而提高目标分割的准确性仍然是一项具有挑战性的工作,针对这一问题,本文提出一种基于双层编—解码结构的算法。方法本文算法由上、下游网络构成,创新性地利用上游网络训练产生注意力权重图,对下游网络解码过程中的特征图产生注意力引导,使分割模型更加注重目标区域;提出子空间通道注意力结构,在跨越连接中提取多分辨率下的跨通道信息,可以有效细化分割边缘;最终输出添加残差结构防止网络退化。结果在公共数据集CVC-ClinicDB(Colonoscopy Videos Challenge-ClinicDataBase)和Kvasir-Capsule上进行测试,采用Dice相似系数(Dice similariy coefficient,DSC)、均交并比(mean intersection over union,mIoU)、精确率(precision)以及召回率(recall)为评价指标,在两个数据集上的DSC分别达到了94.22%和96.02%。进一步将两个数据集混合,测试了算法在跨设备图像上的鲁棒性,其中DSC提升分别达到17%—20%,在没有后处理的情况下,相较其他先进模型(state-of-the-art,SOTA),如U-Net在DSC、mIoU以及recall上分别取得了1.64%、1.41%和2.54%的提升,与ResUNet++的对比中,在DSC以及recall指标上分别取得了2.23%和9.87%的提升,与SFA(selective feature aggregation network)、PraNet和TransFuse等算法相比,在上述评价指标上也均有显著提升。结论本文算法可以有效提高医学图像分割效果,并且对小目标分割、边缘分割具有更高的准确率。

关键词：息肉分割结肠镜检查深度学习语义分割注意力机制医学图像处理

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心脏动态MRI图像分割的时空多尺度网络

中国图象图形学报 2022年第3期27卷 862-872页

作者：徐佳陈肖志勇江南大学人工智能与计算机学院无锡214122

目的心脏磁共振成像(magnetic resonance imaging,MRI)的自动分割技术有利于在临床诊断中评估心脏的功能参数。然而由于心脏磁共振成像技术产生的图像边界不清晰、各向分辨率异性等特性,现有的大多数方法依旧存在类内不确定、类间不清... 详细信息

目的心脏磁共振成像(magnetic resonance imaging,MRI)的自动分割技术有利于在临床诊断中评估心脏的功能参数。然而由于心脏磁共振成像技术产生的图像边界不清晰、各向分辨率异性等特性,现有的大多数方法依旧存在类内不确定、类间不清晰问题。针对这一问题,提出了一种利用时间信息进行特征增强,并利用空间信息进行特征矫正的多输入、多分支和多任务的分割网络(spatio-temporal UNet,ST UNet)。方法为充分获取动态心脏MRI图像的时间信息,提出了全新的时间增强编码模块,将需要进行分割的目标帧和一段包含了目标帧的连续时间片段作为关键序列一同输入网络。关键序列用于获取更丰富的时间特征,目标帧提供更精准的边缘特征。为了聚集更多有益的特征,更好地融合时域特征和边缘特征,采用可变形全局连接代替传统的长连接,为网络的解码部分提供更广泛的多维特征信息。在训练过程中额外学习空间方向场特征,并使用该特征对原有的分割结果进行矫正。结果在ACDC(Automated Cardiac Diagnosis Challenge)心脏分割挑战中,以Dice系数和HD(Hausdorff distance)距离为评价指标,该方法在左心室、右心室和左心肌分割的平均Dice系数分别为95%、91.5%和91%,HD距离的平均值分别为6.77、11.39和8.54。结论实验表明,提出的新型网络能够充分地利用心脏MRI图像的时空信息,有效地提升目标器官的分割效果,更有助于医生对于心脏诊断。

关键词：医学影像心脏磁共振成像(CMRI) 特征增强空间方向场 U型网络(UNet)

面向3维心脏MRI分割的半监督双任务交叉一致性约束网络

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中国图象图形学报 2023年第4期28卷 1198-1211页

作者：苏逸欣肖志勇江南大学人工智能与计算机学院无锡214122

目的针对人体组织器官及病灶区域的3维图像分割是计算机辅助医疗诊断的重要前提,是医学影像3维可视化的重要技术基础。深度学习方法在医学图像分割任务中的成功通常取决于大量有标注数据。半监督学习利用未标注数据容易获取的优点,在模... 详细信息

目的针对人体组织器官及病灶区域的3维图像分割是计算机辅助医疗诊断的重要前提,是医学影像3维可视化的重要技术基础。深度学习方法在医学图像分割任务中的成功通常取决于大量有标注数据。半监督学习利用未标注数据容易获取的优点,在模型训练过程中使用少量标注数据和大量未标注数据进行学习,缓解了数据标注昂贵耗时的问题,在医学图像分割中受到了广泛关注。为更好地利用无标注数据,提升医学图像分割效果,提出一种新的一致性正则方法用于半监督3维医学图像分割。方法模型以V-Net为基础架构,通过扩展网络结构,在均带有分割任务及回归任务属性的双任务主副解码器之间添加了用于正则化约束的交叉损失,构建了具有形状感知的基于双任务的交叉一致性正则网络SACC-Net(shape-aware cross-consistency regular network based on dual tasks),实现将数据层面和模型层面的扰动融合进多任务机制的一致性正则方法,使模型能够更好地利用未标注数据的有效先验信息,并且具有更好的泛化性能。结果在MICCAI 2018(Medical Image Computing and Computer Assisted Intervention Society)心房分割挑战赛公布的数据集中的3维左心房核磁共振成像上验证本文算法,在仅使用训练集中10%的有标注数据的实验组中,Dice系数、Jaccard指数、HD(Hausdorff distance)距离和平均对称表面距离分别为88.01%、78.89%、8.19和2.09。在另一组仅使用20%的有标注数据的实验中Dice系数、Jaccard指数、HD距离和平均对称表面距离分别达到90.11%、82.11%、6.57和1.78。结论本文提出的半监督分割模型性能显著,综合了数据、模型和任务层面的一致性正则约束,与其他半监督方法相比分割效果更好且具有更佳的泛化性能。

关键词：医学影像半监督学习 3维图像分割一致性正则核磁共振图像(MRI)

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改进的U-Net在视网膜血管分割上的应用

计算机科学与探索 2022年第3期16卷 683-691页

作者：谷鹏辉肖志勇江南大学人工智能与计算机学院江苏无锡214122

针对眼底视网膜血管分割中血管边界难以精确识别以及血管与背景对比度低而难以分割的问题,提出一种编码器-解码器结构的算法。为了提高算法在血管边界的分割能力,在编码部分采用全局卷积网络(GCN)和边界细化(BR)替换传统的卷积层;在跳... 详细信息

针对眼底视网膜血管分割中血管边界难以精确识别以及血管与背景对比度低而难以分割的问题,提出一种编码器-解码器结构的算法。为了提高算法在血管边界的分割能力,在编码部分采用全局卷积网络(GCN)和边界细化(BR)替换传统的卷积层;在跳跃连接部分引入改进的位置注意模块(PA)和通道注意模块(CA),目的是增加血管与背景之间的对比度,使网络更好地将血管与背景分割开;此外,为了提高网络的性能,在编码部分的最后一层使用密集卷积网络解决网络过拟合问题,同时为了在一定程度上解决梯度爆炸、梯度消失的问题,在解码部分的每一层使用卷积长短记忆网络提升网络获取特征信息的能力。在公共的数据集DRIVE和CHASE;B1中进行测试,以敏感性、特异性、准确性、F1-Score和AUC为评价指标,其中准确性和AUC分别达到了96.99%、98.77%和97.51%、99.01%。该算法能有效提高眼底图像血管分割的准确率。

关键词：视网膜血管 U-Net 边界细化(BR) 位置注意模块(PA) 通道注意模块(CA) 全局卷积网络(GCN)