941 research outputs found

    Extrusion-based 3D Printing of Macro/Microstructures for Advanced Lithium/Sodium Batteries

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    With the development of electronics and electric vehicles, high-performance batteries with high energy density, high safety, and aesthetic diversity are greatly needed as dominating power sources. However, the electrodes and electrolytes fabricated with traditional techniques have limited form factors, mechanical flexibility, and poor performance. Extrusion-type 3D printing techniques have thus been applied to fabricate 3D batteries with high performance since 3D printing techniques have great advantages in the fabrication of complex 3D structures and geometric shapes from various materials. The research in this thesis aims at fabricating high-performance Li/Na batteries via 3D printing of advanced electrodes and solid electrolytes

    Revisit to Non-decoupling MSSM

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    Dipole operator sˉσμνFμνb\bar{s}\sigma_{\mu\nu}F^{\mu\nu}b requires the helicity flip in the involving quark states thus the breaking of chiral U(3)Q×U(3)dU(3)_{Q}\times U(3)_{d}. On the other hand, the bb-quark mass generation is also a consequence of chiral U(3)Q×U(3)dU(3)_{Q}\times U(3)_{d} symmetry breaking. Therefore, in many models, there might be strong correlation between the bsγb\to s\gamma and bb quark Yukawa coupling. We use non-decoupling MSSM model to illustrate this feature. The light Higgs boson may evade the direct search experiments at LEPII or Tevatron while the 125 GeV Higgs-like boson is identified as the heavy Higgs boson in the spectrum. A light charged Higgs is close to the heavy Higgs boson which is of 125 GeV and its contribution to bsγb\to s \gamma requires large supersymmetric correction with large PQ and RR symmetry breaking. The large supersymmetric contribution at the same time significantly modifies the bb quark Yukawa co upling. With combined flavor constraints BXsγB\to X_{s}\gamma and Bsμ+μB_{s}\to \mu^{+}\mu^{-} and direct constraints on Higgs properties, we find best fit scenarios with light stop of O\cal O(500 GeV), negative AtA_{t} around -750 GeV and large μ\mu-term of 2-3 TeV. In addition, reduction in bbˉb\bar{b} partial width may also result in large enhancement of ττ\tau\tau decay branching fraction. Large parameter region in the survival space under all bounds may be further constrained by HττH\to \tau\tau if no excess of ττ\tau\tau is confirmed at LHC. We only identify a small parameter region with significant HhhH\to hh decay that is consistent with all bounds and reduced ττ\tau\tau decay branching fraction.Comment: 18pages, 6 figure

    Getting your Accounting Right

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    Can the Black Lives Matter Movement Reduce Racial Disparities? Evidence from Medical Crowdfunding

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    Using high-frequency donation records from a major medical crowdfunding site and careful difference-in-difference analysis, we demonstrate that the 2020 BLM surge decreased the fundraising gap between Black and non-Black beneficiaries by around 50\%. The reduction is largely attributed to non-Black donors. Those beneficiaries in counties with moderate BLM activities were most impacted. We construct innovative instrumental variable approaches that utilize weekends and rainfall to identify the global and local effects of BLM protests. Results suggest a broad social movement has a greater influence on charitable-giving behavior than a local event. Social media significantly magnifies the impact of protests

    Image retrieval based on colour and improved NMI texture features

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    This paper proposes an improved method for extracting NMI features. This method uses Particle Swarm Optimization in advance to optimize the two-dimensional maximum class-to-class variance (2OTSU) in advance. Afterwards, the optimized 2OUSU is introduced into the Pulse Coupled Neural Network (PCNN) to automatically obtain the number of iterations of the loop. We use an improved PCNN method to extract the NMI features of the image. For the problem of low accuracy of single feature, this paper proposes a new method of multi-feature fusion based on image retrieval. It uses HSV colour features and texture features, where, the texture feature extraction methods include: Grey Level Co-occurrence Matrix (GLCM), Local Binary Pattern (LBP) and Improved PCNN. The experimental results show that: on the Corel-1k dataset, compared with similar algorithms, the retrieval accuracy of this method is improved by 13.6%; On the AT&T dataset, the retrieval accuracy is improved by 13.4% compared with the similar algorithm; on the FD-XJ dataset, the retrieval accuracy is improved by 17.7% compared with the similar algorithm. Therefore, the proposed algorithm has better retrieval performance and robustness compared with the existing image retrieval algorithms based on multi-feature fusion

    A Review on Progress in QSPR Studies for Surfactants

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    This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (γ) of surfactants are introduced. Studies on charge distribution in ionic surfactants by quantum chemical calculations and its effects on the structures and properties of the colloids of surfactants are also reviewed. The trends of QSPR studies on cloud point (for nonionic surfactants), biodegradation potential and some other properties of surfactants are evaluated

    Are Human-generated Demonstrations Necessary for In-context Learning?

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    Despite the promising few-shot ability of large language models (LLMs), the standard paradigm of In-context Learning (ICL) suffers the disadvantages of susceptibility to selected demonstrations and the intricacy to generate these demonstrations. In this paper, we raise the fundamental question that whether human-generated demonstrations are necessary for ICL. To answer this question, we propose self-contemplation prompting strategy (SEC), a paradigm free from human-crafted demonstrations. The key point of SEC is that, instead of using hand-crafted examples as demonstrations in ICL, SEC asks LLMs to first create demonstrations on their own, based on which the final output is generated. SEC is a flexible framework and can be adapted to both the vanilla ICL and the chain-of-thought (CoT), but with greater ease: as the manual-generation process of both examples and rationale can be saved. Extensive experiments in arithmetic reasoning, commonsense reasoning, multi-task language understanding, and code generation benchmarks, show that SEC, which does not require hand-crafted demonstrations, significantly outperforms the zero-shot learning strategy, and achieves comparable results to ICL with hand-crafted demonstrations. This demonstrates that, for many tasks, contemporary LLMs possess a sufficient level of competence to exclusively depend on their own capacity for decision making, removing the need for external training data. Code is available at https://github.com/ruili33/SEC
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