122 research outputs found

    Light-weight Mg/Al dissimilar structures welded by CW laser for weight saving applications

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    With the increasing demand of light-weight alloys, such as magnesium (Mg) and aluminum (Al), the need for joining these two alloys is unavoidable. In this study, AZ31B Mg and 1060 Al alloys were joined by continuous wave laser micro-welding using a 0.05 mm thick Cu/Zn interlayer. The microstructure and phases constituent of the weld seam were examined by optical microscope, SEM and EDS. The formation and distribution of the intermetallic compounds (IMCs) and the relationship between these structures and the micro-hardness of the weld were discussed in detail. The effect of Cu/Zn interlayer on the performance of Mg/Al joint was also analyzed. The results showed that Mg/Al IMCs were formed in the weld, which indicates that the Cu/Zn foil could not prevent the reaction between Mg and Al. However, the addition of Cu and Zn into the weld pool refined the microstructure by improving the number of eutectic structures. The micro-hardness of Mg/Al IMCs in the middle of the weld was very high which can be detrimental to the toughness of the Mg/Al joints

    POWER SAVING METHOD FOR PLUGGABLE OPTICAL TRANSCEIVERS

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    Today, when optical transceivers are plugged into ports of network equipment and a user administratively shuts down a specific port, the network equipment does not remove the power from the optical transceivers and, instead, only the laser is shut down. When the user shuts the individual port with optical transceiver, the power consumption of the optical transceiver will be marginally reduced, however significant power is still consumed. Techniques described herein provide for switching products that are always ready, not always on. Techniques described herein provide for ports that are always ready to be powered up but are powered down when not in use to save power

    Preclinical investigation of an innovative magnesium-based bone graft substitute for potential orthopaedic applications

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    SummaryDegradable or corrosive biometal is an attractive research and development (R&D) area in clinical orthopaedics. This study was designed to investigate biomechanical and biological properties of magnesium (Mg) and strontium (Sr) with a focus on Mg-based metals, including pure Mg and Mg–xwt% Sr (x = 0.25, x = 1.0, x = 1.5, x = 2.5) alloys, as potential bone graft substitutes in respect to their mechanical strength, corrosion resistance, and cytocompatibility for further optimization and establishing indications for relevant in vivo applications. Our data showed that the tensile and compressive strength increased with addition of Sr because of the Mg17Sr2 precipitation strengthen. Compared with commercially used bone graft substitutes, the mechanical properties of Mg–Sr alloys were close to those of cortical bone, and the compressive strength could reach 300 MPa, suggesting its potential application for load-bearing bone as bone defect filler. The corrosion rates of Mg–xwt% Sr alloys were controlled in the range of 0.05–0.07 mm/y, indicating feasibility of bone grafting and the in situ bone repair process. Moreover, Mg–Sr alloys also exhibit good cytocompatibility and antibacterial properties. Our innovation presented in this work supported in vivo clinical indication-based assessment of biodegradable Mg-based metals that could be potential candidates for bone graft substitutes for future orthopaedic applications

    Priority-Centric Human Motion Generation in Discrete Latent Space

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    Text-to-motion generation is a formidable task, aiming to produce human motions that align with the input text while also adhering to human capabilities and physical laws. While there have been advancements in diffusion models, their application in discrete spaces remains underexplored. Current methods often overlook the varying significance of different motions, treating them uniformly. It is essential to recognize that not all motions hold the same relevance to a particular textual description. Some motions, being more salient and informative, should be given precedence during generation. In response, we introduce a Priority-Centric Motion Discrete Diffusion Model (M2DM), which utilizes a Transformer-based VQ-VAE to derive a concise, discrete motion representation, incorporating a global self-attention mechanism and a regularization term to counteract code collapse. We also present a motion discrete diffusion model that employs an innovative noise schedule, determined by the significance of each motion token within the entire motion sequence. This approach retains the most salient motions during the reverse diffusion process, leading to more semantically rich and varied motions. Additionally, we formulate two strategies to gauge the importance of motion tokens, drawing from both textual and visual indicators. Comprehensive experiments on the HumanML3D and KIT-ML datasets confirm that our model surpasses existing techniques in fidelity and diversity, particularly for intricate textual descriptions.Comment: Accepted by ICCV202

    Biodiversity and temporal patterns of macrozoobenthos in a coal mining subsidence area in North China

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    Coal resources play a strategic role in the long-term development of China. Large-scale mining has a considerable impact on the landscape, and it is a long-term heritage of industrialization unique to the Anthropocene. We investigated the macrozoobenthos and water in nine mining subsidence wetlands at different developmental stages (3–20 years) in North China. A total of 68 species were found, and the macrozoobenthos community in the newly formed wetlands showed high diversity. We believe that this high diversity is not random; rather, the high diversity was because of the special origin and development of the wetland. We used three time slices from the timeline of the development of the newly formed wetlands and compared them. It was found that the macrozoobenthos community was significantly affected by the change in the subsidence history. We emphasize that coal mining subsidence should not be merely identified as secondary man-made disasters, as they are often secondary habitats with high conservation value, and their conservation potential lies in the fact that these secondary habitats can replace rapidly decreasing natural wetlands

    TM2D: Bimodality Driven 3D Dance Generation via Music-Text Integration

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    We propose a novel task for generating 3D dance movements that simultaneously incorporate both text and music modalities. Unlike existing works that generate dance movements using a single modality such as music, our goal is to produce richer dance movements guided by the instructive information provided by the text. However, the lack of paired motion data with both music and text modalities limits the ability to generate dance movements that integrate both. To alleviate this challenge, we propose to utilize a 3D human motion VQ-VAE to project the motions of the two datasets into a latent space consisting of quantized vectors, which effectively mix the motion tokens from the two datasets with different distributions for training. Additionally, we propose a cross-modal transformer to integrate text instructions into motion generation architecture for generating 3D dance movements without degrading the performance of music-conditioned dance generation. To better evaluate the quality of the generated motion, we introduce two novel metrics, namely Motion Prediction Distance (MPD) and Freezing Score, to measure the coherence and freezing percentage of the generated motion. Extensive experiments show that our approach can generate realistic and coherent dance movements conditioned on both text and music while maintaining comparable performance with the two single modalities. Code will be available at: https://garfield-kh.github.io/TM2D/

    Study on microstructure and tensile properties of high nitrogen Cr-Mn steel processed by CMT wire and arc additive manufacturing

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    A designed Cr-Mn-N wire with 0.99 wt% of nitrogen content (HNS0.99) was used to make high nitrogen austenite stainless steel parts by introducing CMT wire and arc additive manufacturing (CMT-WAAM) method. The solidification behaviour, microstructure evolution, inclusions and tension properties were studied both in the as-built and post heat treatment conditions. Excellent tension properties parts with high nitrogen content were successfully produced. Ferrite-austenite (FA) and austenite-ferrite (AF) solidification models were revealed in the as-built microstructure of two different areas, inner layer area (ILA) and partial melting area (PMA), respectively, and the former predominated the microstructure. Amorphous inclusion islands and microspherical inclusions made by MnO were found. The increasing density of the latter in 0.1-1 μm diameters was detrimental to the tensile properties because the matrix-inclusion surfaces acted as the preferred nucleation sites for Cr2N during heat treatment. Due to the stable austenite and the nitrogen work hardening effect, planer dislocation-arrays predominated the dislocation slip model which, to some extent, diminished the strength anisotropy in different directions. However, the ferrite dendrites caused the diversity of UTS and elongation by acting as tunnels for cracks in the horizontal direction samples

    Effect of transcranial direct current stimulation for patients with disorders of consciousness: A systematic review and meta-analysis

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    IntroductionTranscranial direct current stimulation (tDCS) could potentially facilitate consciousness improvement in patients with disorders of consciousness (DOC). The aim of this study was to investigate the therapeutic efficacy of tDCS on consciousness recovery for patients with DOC.MethodsEight databases were systematically searched from their inception to June 2022. Quality of included studies were assessed using PEDro score and Cochrane’s risk of bias assessment. All statistical analyses were performed using RevMan software. Seventeen studies with 618 patients were identified eligible for this study, and fifteen studies with sufficient data were pooled in the meta-analysis.ResultsThe results of meta-analysis showed a significant effect on increasing GCS scores (MD = 1.73; 95% CI, 1.28–2.18; P < 0.01) and CRS-R scores (MD = 1.28; 95% CI = 0.56–2.00; P < 0.01) in favor of the real stimulation group as compared to sham. The results of subgroup analysis demonstrated that only more than 20 sessions of stimulation could significantly enhance the improvement of GCS scores and the CRS-R scores. Moreover, the effect of tDCS on CRS-R score improvement was predominant in patients with minimal conscious state (MCS) (MD = 1.84; 95% CI = 0.74–2.93; P < 0.01).ConclusionAnodal tDCS with sufficient stimulation doses appears to be an effective approach for patients with MCS, in terms of CRS-R scores.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022336958

    Mycobacterium tuberculosis -Induced Upregulation of the COX-2/mPGES-1 Pathway in Human Macrophages Is Abrogated by Sulfasalazine

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    Macrophages are the primary human host cells of intracellular Mycobacterium tuberculosis ( M.tb ) infection, where the magnitude of inflammatory reactions is crucial for determining the outcome of infection. Previously, we showed that the anti-inflammatory drug sulfasalazine (SASP) significantly reduced the M.tb bactericidal burden and histopathological inflammation in mice. Here, we asked which genes in human inflammatory macrophages are affected upon infection with M.tb and how would potential changes impact the functional state of macrophages. We used a flow cytometry sorting system which can distinguish the dead and alive states of M.tb harbored in human monocyte-derived macrophages (MDM). We found that the expression of cyclooxygenase-2 and microsomal prostaglandin E 2 synthase (mPGES)-1 increased significantly in tagRFP + MDM which were infected with alive M.tb . After exposure of polarized M1-MDM to M.tb (H37Rv strain)-conditioned medium (MTB-CM) or to the M.tb -derived 19-kD antigen, the production of PGE 2 and pro-inflammatory cytokines increased 3- to 4-fold. Upon treatment of M1-MDM with SASP, the MTB-CM-induced expression of COX-2 and the release of COX products and cytokines decreased. Elevation of PGE 2 in M1-MDM upon MTB-CM stimulation and modulation by SASP correlated with the activation of the NF-κB pathway. Together, infection of human macrophages by M.tb strongly induces COX-2 and mPGES-1 expression along with massive PGE 2 formation which is abrogated by the anti-inflammatory drug SASP
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