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Danying Wang,Mengqing Zang,Hengyuan Ma,Yuanbo Liu 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.3
Reconstruction of soft tissue defects around the knee is challenging, and the most common solution is to use various locoregional flaps or, in some difficult cases, a free flap. The distally based anterolateral thigh (dALT) flap is a commonly used flap that relies on reverse blood flow from the descending branch of the lateral circumflex femoral artery (d-LCFA). Here, we present the case of an anteromedial knee reconstruction using a dALT flap after resection of a pleomorphic undifferentiated sarcoma. The tumor resection resulted in a 147 cm defect, and a dALT flap, measuring 208 cm was elevated. During the surgery, we found a robust oblique branch of the LCFA (o-LCFA) sending off two sizable perforators to the anterolateral thigh region, whereas the d-LCFA was relatively small with no usable perforators. Therefore, we harvested a dALT flap relying on reverse flow from the o-LCFA. The patient’s postoperative course was uneventful, and the flap survived without complications. This report demonstrates that reverse flow from the o-LCFA may be an alternative to nourish a dALT flap in cases where the d-LCFA is hypoplastic or suitable perforators from the d-LCFA are unavailable.
Yan Wang,Lichen Gu,Yuanbo Xu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
The bearing fault signal is a kind of weak signal, so it is easy to be submerged by background noise. As such, signature extraction is facing a great challenge; hence, an effective signature extraction method plays an essential role in bearing fault extraction. In this paper, a new method for bearing fault detection based on an alternative analytic energy operator and sparse Bayesian step-filtering (SBSF) was applied. The SBSF technique can remove much background noise from the raw signal and enhance the characteristics related to the bearing fault. Besides, it has also a high calculation efficiency. Afterward, an improved analytic energy operator, the symmetric high-order analytic energy operator (SHO-AEO), which is an enhanced demodulation technique that outperforms the conventional demodulation technique, was applied to detect bearing fault signatures from filtered signals. The proposed energy measure is formed using the original signal, its Hilbert transform, and its high-order derivatives. Unlike traditional energy operators, it includes the information of the real and imaginary parts of the analytic signal. As a demodulation technique, it is also tailored to extract both the amplitude and frequency modulations from the filtered signal. Furthermore, compared with the previous energy operators, it provides better anti-noise capability. Hence, the proposed fault detection method of combining the SHO-AEO and SBSF not only has high computational efficiency but also provides much better noise handling potential. Through simulated and real tests, this proposed method is demonstrated to be robust against various noise levels and to detect the bearing fault signature.
Emergence of Tertiary Dirac Points in Graphene Moiré Superlattices
Chen, Guorui,Sui, Mengqiao,Wang, Duoming,Wang, Shuopei,Jung, Jeil,Moon, Pilkyung,Adam, Shaffique,Watanabe, Kenji,Taniguchi, Takashi,Zhou, Shuyun,Koshino, Mikito,Zhang, Guangyu,Zhang, Yuanbo American Chemical Society 2017 NANO LETTERS Vol.17 No.6
<P>The electronic structure of a crystalline solid is largely determined by its lattice structure. Recent advances in van der Waals solids, artificial crystals with controlled stacking of two-dimensional (2D) atomic films, have enabled the creation of materials with novel electronic structures. In particular, stacking graphene on hexagonal boron nitride (hBN) introduces a moire superlattice that fundamentally modifies graphenes band structure and gives rise to secondary Dirac points (SDPs). Here we find that the formation of a moire superlattice in graphene on hBN yields new, unexpected consequences: a set of tertiary Dirac points (TDPs) emerge, which give rise to additional sets of Landau levels when the sample is subjected to an external magnetic field. Our observations hint at the formation of a hidden Kekule superstructure on top of the moire superlattice under appropriate carrier doping and magnetic fields.</P>
Investigation on High Temperature Mechanical Behaviors of TiC-γ′ Reinforced Ni Composite
Wenqiang Hu,Zhenying Huang,Qun Yu,Yuanbo Wang,Yidan Jiao,Yang Zhou,Hongxiang Zhai 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8
A duplex TiC and γ′-Ni3(Al,Ti) reinforced nickel composite was fabricated through hot-press sintering a 30 vol% Ti2AlC–Nimixtures followed by thermal treatment method. Detailed microstructural detection was performed by adopting the routeof high-resolution transmission electron microscopy. In situ generated submicron TiC particulate and nanosized L12-γ′were homogeneously distributed in a fcc γ-Ni matrix. The high temperature tensile and compression behaviors of the TiC-γ′/Ni composites were evaluated in the temperature range of 25–800 °C. The results indicated that ultimate tensile andcompression properties exhibited the dependence of temperatures. The tensile properties of the composite determined at600 °C was 945 MPa, decreasing by 28.1% and 23.0% for elongation, compared to those of measured at room temperature(UTS = 1305 MPa, elongation = 5.35%). However, the yield strength exhibited the temperature independent until to 600 °C. The yield strength of the TiC-γ′/Ni composite are comparable with conventional superalloy under 600 °C, proving that TiCand γ′ particles constitute efficient reinforcements for Ni matrix according to thermal expansion dislocations strengthening,load-transfer and coherent strengthening mechanisms. The monotonic temperature dependence of yield strength at600–800 °C indicates that plastic deformation of TiC-γ′/Ni composite follows the thermally activated mechanism. TheTiC-γ′/Ni composite exhibited superior mechanical properties both at room and high temperatures, which can be ascribedto the synergistic strengthening effect in term of dislocation density, Orowan, coherent and atomic ordering strengtheningmechanisms. The present work reveals the deformation behaviors of in situ TiC-γ′/Ni composite from room to high temperatures,which is critical to predict the failure and thereby optimize the microstructure to further enhance the high temperatureproperties of TiC-γ′/Ni composite.
Thermal Shock Behavior of a Novel TiCx–Ni3(Al,Ti)/Ni Functionally Graded Composite
Qun Yu,Zhenying Huang,Guangming Zheng,Wenqiang Hu,Cong Lei,Yuanbo Wang,Yidan Jiao,Hongxiang Zhai 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12
This paper focuses on the study of thermal shock behaviors of a novel TiCx–Ni3(Al,Ti)/Ni functionally graded material (FGM)fabricated from Ti3AlC2and Ni powders. Thermal shock resistance of resulted FGM was conducted by water quenching atdifferent temperatures, mechanical properties and microstructures after thermal shocks were correspondingly determined andcharacterized. The microstructure of the FGM after thermal shocks shows no cracks of instability failure between the transitionzones, and the reinforcement phases were closely combined with the matrix. Meanwhile, compared with the strengthof 1329 MPa without thermal shock, when the temperature of the thermal shock reached 800 °C and 1000 °C respectively,with 10 repeated heat-water quench cycles, the residual flexural strength of FGM decreased slightly, but it could still reach1100 MPa. Notably, the strength can still maintain at 843 MPa after 10 cycles of thermal shock at 1200 °C. Such excellentthermal shock performance may be the result of the good interfacial bonding and the special gradient structure, the oxidationlayer also plays a protective role.
Guangming Zheng,Zhenying Huang,Qun Yu,Wenqiang Hu,Xingyang Qiu,A. Lixia,Yuanbo Wang,Yidan Jiao,Yang Zhou,Hongxiang Zhai 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6
In this paper, a novel type of functionally graded material (FGM) was successfully fabricated from pure Ni and Ti3AlC2powder mixtures by hot-press sintering route at 1200 °C and 17 MPa. In each layer, Ti3AlC2particles transformed into TiCxphase, while the additional Al–Ti atoms decomposed from Ti3AlC2diffused into the Ni matrix, giving rise to the formationof γ′-Ni3(Al,Ti). Part of the submicron TiCxand Ni3(Al,Ti) particles were uniformly distributed in the Ni matrix, whilesome of the TiCxmaintained the original Ti3AlC2plate-like morphology. Both TiCxand Ni3(Al,Ti) content decreased from60Ti3AlC2/Ni layer to 10Ti3AlC2/Ni layer in a stepwise manner was fabricated. The microstructural analysis indicatesthat no cracks, delamination and step-type abrupt changes occured in the graded layer of the manufactured FGM. Flexuralstrength and Vickers hardness enhanced with the increasing Ti3AlC2content except for fracture strain and toughness. Theoverall fracture toughness and the flexural strength of FGM can reach 21.76 MPa m1/2 and 1329 ± 34 MPa, respectively. Theprepared FGM, herein, with a hard ceramic surface on one side to resist local plastic deformation, and a ductile metallicsurface on the other side to provide toughness.
Evidence of a gate-tunable Mott insulator in a trilayer graphene moiré superlattice
Chen, Guorui,Jiang, Lili,Wu, Shuang,Lyu, Bosai,Li, Hongyuan,Chittari, Bheema Lingam,Watanabe, Kenji,Taniguchi, Takashi,Shi, Zhiwen,Jung, Jeil,Zhang, Yuanbo,Wang, Feng NATURE PUBLISHING GROUP 2019 NATURE PHYSICS Vol.15 No.3