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Electronic regulation of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is a crucial step towards next-generation optoelectronics and electronics. Here, we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide (MoS2) using a focused ion beam with a low-energy gallium ion (Ga+) source. We find that the surface defects of MoS2 can be tuned by the precise control of ion energy and dose. Furthermore, the field-effect transistors based on the monolayer MoS2 show a significant threshold voltage modulation over 70 V after Ga+ irradiation. First-principles calculations reveal that the Ga impurities in the monolayer MoS2 introduce a defect state near the Fermi level, leading to a shallow acceptor level of 0.25 eV above the valence band maximum. This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner, tailoring the electronic properties of 2D TMDCs for novel devices.

Background Distinguishing multiple primary lung cancer (MPLC) from intrapulmonary metastasis (IPM) is critical for their disparate treatment strategy and prognosis. This study aimed to establish a non-invasive model to make the differentiation pre-operatively. Methods We retrospectively studied 168 patients with multiple lung cancers (307 pairs of lesions) including 118 cases for modeling and internal validation, and 50 cases for independent external validation. Radiomic features on computed tomography (CT) were extracted to calculate the absolute deviation of paired lesions. Features were then selected by correlation coefficients and random forest classifier five-fold cross-validation, based on which the lesion pair relation estimation (PRE) model was developed. A major voting strategy was used to decide diagnosis for cases with multiple pairs of lesions. Cases from another institute were included as the external validation set for the PRE model to compete with two experienced clinicians. Results Seven radiomic features were selected for the PRE model construction. With major voting strategy, the mean area under receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity of the training vs. internal validation vs. external validation cohort to distinguish MPLC were 0.983 vs. 0.844 vs. 0.793, 0.942 vs. 0.846 vs. 0.760, 0.905 vs. 0.728 vs. 0.727, and 0.962 vs. 0.910 vs. 0.769, respectively. AUCs of the two clinicians were 0.619 and 0.580. Conclusions The CT radiomic feature-based lesion PRE model is potentially an accurate diagnostic tool for the differentiation of MPLC and IPM, which could help with clinical decision making.

Vapor bubble behaviors under saturated pool boiling are investigated numerically and experimentally. For this, bubble dynamics such as the growth and detachment processes are simulated and discussed. The impacts of contact angle and surface structures on bubble dynamics as well as heat transfer performances are also presented. In this process, conservation equations of mass, momentum, and energy are numerically solved by commercial software ANSYS Fluent 18.1. In particular, the bubble departure diameters on flat heated surfaces are compared with theoretical model and experiments. Bubble period and wall heat flux are closely related to the velocity field around the contact line region. The numerical results also show that for a bubble growing on pillar surface, flow field around the pillar plays a significant role in the variation of bubble shape as well as an enhanced wall heat flux. Time-evolution images of single bubble evolution in pool boiling experiments are captured through a high-speed camera. Bubble behaviors from experiment and simulation show a good consistency.

The magneto-electro-elastic coupling static problem for a functionally graded piezoelectric-piezomagnetic (FGPEPM) cylinder/spherical shell is studied for various axial/spherical symmetric loads. On the basis of unified basic equations with geometric parameters and the material assumption of exponential inhomogeneous properties, the analytical solutions for the physical quantities of displacement, stress, electric potential, and magnetic potential of the FGPEPM hollow cylinder/spherical shell are obtained. In the numerical discussions, the static response of the FGPEPM cylinder/spherical shell is numerically solved under mechanical load on the inner surface or given an electric/magnetic potential difference between the inner and outer surfaces when the material on the inner surface is assumed to be BaTiO3-CoFeO4. The distribution of radial and circumferential stress and the electric and magnetic potentials under different functionally graded (FG) parameters are presented. The influence of FG parameters on the positive (converse) piezoelectric, positive (converse) piezomagnetic, and positive (converse) magnetoelectric potentials is discussed in detail.