基于nnU-Net的乳腺DCE-MR图像中乳房和腺体自动分割

在乳腺动态增强磁共振（DCE-MR）图像中,乳房分割和腺体分割是进行乳腺癌风险评估的关键步骤.为实现在三维脂肪抑制乳腺DCE-MR图像中乳房和腺体的自动分割,本文提出一种基于nnU-Net的自动分割模型,利用U-Net分层学习图像特征的优势,融合深层特征与浅层特征,得到乳房分割和腺体分割结果.同时,基于nnU-Net策略,所使用的模型能根据图像参数自动进行预处理和数据扩增,并动态调整网络结构和参数配置.实验结果表明,在具有多样化参数的三维脂肪抑制乳腺DCE-MR图像数据集上,该模型能准确、有效地实现乳房和腺体分割,平均Dice相似系数分别达到0.969±0.007和0.893±0.054.     

Structure elucidation and complete NMR spectral assignment of an unusual aromatic monacolin analog from Monascus purpureus-fermented rice

One unusual aromatic monacolin analog, monacophenyl, was isolated from the ethanolic extract of Monascus purpureus-fermented rice. Its structure was completely and unambiguously assigned by one- and two-dimensional NMR techniques ((1)H NMR, (13)C NMR, HSQC, HMBC and NOESY) and high-resolution ESI-MS spectrometry.     

A Novel 3D Cobalt（II） Complex Constructed by 2,2＇-（1,4-Butanediyl）bis（1H-benzimidazole） Ligand

A novel 3D polymer 1 (C26H22CoN4O4, Mr = 513.41) constructed from H2C4BIm (2,2'-(1,4-butanediyl)bis(1H-benzimidazole)], 1,3-bdc (1,3-benzenedicarboxylate) and Co(II) has been successfully synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analysis. The crystal belongs to the tetragonal system, space group I-42d with a = 24.315(5), b = 24.315(5), c = 8.343(2), V = 4933(2)3, Z = 8, Dc = 1.383 g/cm3, μ(MoKα) = 0.735 mm-1, F(000) = 2120, S = 1.156, the final R = 0.0596 and wR = 0.1346 for 1529 reflections with I > 2σ(I). Complex 1 contains 1D chains which are connected by extensive hydrogen-bonding interactions to form the 2D folded layer and 3D framework, which also stabilize the structure.     

Synthesis of large surface area nano-sized BiVO4 by an EDTA-modified hydrothermal process and its enhanced visible photocatalytic activity

In this work, monoclinic scheelite-type BiVO₄ nanoparticle with large surface area has been successfully synthesized, using Bi(NO₃)₃ and NH₄VO₃ as raw materials, through a hydrothermal process in the presence of ethylene diamine tetraacetic acid (EDTA). It is demonstrated that the nanoparticle size of as-prepared BiVO₄ becomes small by decreasing hydrothermal temperature, shortening hydrothermal reaction time and increasing EDTA amount used. The resulting BiVO₄ nanoparticle with large surface area exhibits a good photocatalytic performance for degrading phenol solution as a model organic pollutant under visible illumination. The key of this method is the chelating role of EDTA group in the synthetic process that it can greatly control the concentration of Bi³⁺, leading to the growth inhibition of BiVO₄ crystallite. The work provides a route for the synthesis of Bi-containing nano-sized composite oxides with large surface area.     

Structural and optical properties of Ga2O3:In films deposited on MgO (1 0 0) substrates by MOCVD

Ga₂O₃:In films with different indium (In) content x [x=In/(Ga+In) atomic ratio] have been deposited on MgO (1 0 0) substrates by metalorganic chemical vapor deposition (MOCVD). Structural analyses revealed that the film deposited with actual In content (x′) of 0.09 was an epitaxial film and the films with x′=0.18 and 0.37 had mixed-phase structures of monoclinic Ga₂O₃ and bixbyite In₂O₃. The absolute average transmittance of the obtained films in the visible region exceeded 95%, and the band gap was in the range of 4.74-4.87 eV. Photoluminescence (PL) measurements were performed at room temperature, in which the visible luminescences were strong and could be seen by the naked eye. The strong emissions in the visible light region were proposed to originate from the gallium vacancies, oxygen deficiencies and other defects in these films.     

Study on a novel vertical enhancement-mode Ga2O3 MOSFET with FINFET structure

A novel enhanced mode(E-mode)Ga₂O₃ metal-oxide-semiconductor field-effect transistor(MOSFET)with vertical FINFET structure is proposed and the characteristics of that device are numerically investigated.It is found that the concentration of the source region and the width coupled with the height of the channel mainly effect the on-state characteristics.The metal material of the gate,the oxide material,the oxide thickness,and the epitaxial layer concentration strongly affect the threshold voltage and the output currents.Enabling an E-mode MOSFET device requires a large work function gate metal and an oxide with large dielectric constant.When the output current density of the device increases,the source concentration,the thickness of the epitaxial layer,and the total width of the device need to be expanded.The threshold voltage decreases with the increase of the width of the channel area under the same gate voltage.It is indicated that a set of optimal parameters of a practical vertical enhancement-mode Ga₂O₃ MOSFET requires the epitaxial layer concentration,the channel height of the device,the thickness of the source region,and the oxide thickness of the device should be less than 5×10¹⁶ cm^-3,less than 1.5μm,between 0.1μm-0.3μm and less than 0.08μm,respectively.     

任意发光类型的多色光照明下光栅塔尔博特效应的研究

利用部分相干光理论对多色光源照明下光栅的菲涅耳衍射进行了理论分析,得到了适用于任意发光类型(脉冲或连续发光)的多色光源的衍射光强的一般公式,理论结果表明菲涅耳衍射区的平均衍射光强的形式只与光源的频谱分布有关,这对借助于连续发光光源来研究脉冲光源照明下光栅的塔尔博特效应以及用来确定脉冲光源的性能参量提供了有力的参考依据。此外,详细讨论了光源的频谱分布对光栅塔尔博特效应的影响并进行了相应的数值计算。实验中通过选用不同频率的激光分别照明光栅,拍摄到对应于不同频率的衍射光强分布图像,从而间接获得多色光同时照明光栅时总的衍射光强分布。实验结果表明,理论和实验符合较好。     

测定固体材料物理量的光学方法

本给出了用光学测量固体材料物理量的三种方法,并对其不同结果进行比较。其光纤测量方法结果误差最小。     

Luminescent properties of SrMg<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>2</Subscript>:Eu<Superscript>2+</Superscript>, and Mn<Superscript>2+</Superscript> as a potential phosphor for ultraviolet light-emitting diodes

Eu²⁺ and Mn²⁺ co-doped SrMg₂(PO₄)₂ phosphors with blue and red two emission bands were prepared by the high temperature solid state method and their luminescent properties have been investigated as a function of activator and co-activator concentrations. Resonance-type energy transfers from Eu²⁺ to Mn²⁺ were discovered by directly overlapping the Eu²⁺ emission spectrum and the excitation spectrum of Mn²⁺. Efficiencies of energy transfer were also calculated according to the changes of relative intensities of Eu²⁺ and Mn²⁺ emission. According to the principle of energy transfer, we demonstrated that the phosphor SrMg₂(PO₄)₂:Eu²⁺,Mn²⁺ with double emission bands exhibited a great potential as a phosphor for ultraviolet light-emitting diodes and the relative intensities of blue and red emission could be tuned by adjusting the contents of Eu²⁺ and Mn²⁺. PACS 78.55.-m