Continuous Hydrothermal Flow Synthesized Transition Metal Oxides and Chalcogenides for Secondary Energy Storage Systems

Efficient energy storage is the key to faciltating the widespread use of portable electronics, electric and hybrid vehicles, and residential energy storage. Recently, technologies such as Li-ion, Na-ion and Zn-air batteries have been identified as suitable solutions for energy storage devices. Li-ion and Na-ion -based systems have the capability to provide high gravimetric and volumetric energy densities together with the ability to supply energy for demanding, high-power applications. Zn-air batteries combine the best aspects of fuel-cell and a conventional redox battery in a single package, providing high volumetric energy density, improved safety aspects, ease of transportation, and the ability to work in an open-system under atmospheric conditions. However, existing synthesis methods may not be optimal for industrial applications, where a continuous, scaleable, environmentally-friendly, and consistent approach is desirable. To meet such requirements, Continuous Hydrothermal Flow Synthesis (CHFS) provides a suitable approach that allows for the scaleable production of nanomaterials, such as metal oxides, sulfides, or composite materials, with high physical consistency and narrow size distributions. Moreover, CHFS is particularly suited for combinatorial studies on the effects of dopant introduction and compositional variation on compounds of interest, as the output formulaic composition can be finely-tuned through control over the precursor concentration and flow rates. In this study, CHFS has been utilized to produce phase-pure nanostructured electrode materials for the first time. In Li-ion and Na-ion half-cells, nanostructured sodium titanate and cobalt nickel sulfide were investigated as an insertion and conversion anode materials, respectively. The high surface area sodium titanates exhibited additional pseudocapacitive charge storage mechanisms the became more pronounced in Na-ion half-cells. For the cobalt nickel sulfides, in-situ carbon-coating and post-synthesis heat-treatments were shown to increase cycling stability and specific capacity of the anode material, with the former introducing pseudocapacitive charge storage mechanisms and aiding in buffering destructive volume change, while the latter aiding in the evolution of structurally stable monometallic phases capable of synergistic interactions with bimetallic sulfide components. Cobalt nickel sulfides were also evaluated as bifunctional electrocatalysts and as air-cathodes for Zn-air batteries, where their performance was optimized by altering their formulaic composition through varying the proportion of its metallic precursors, and the introduction of tertiary transition-metal dopants. The improved performance was attributed to the high surface area, the favourable tuning of existing nickel and cobalt cation ratios, and the inherent activity of the dopant cations themselves

Aquatic landscape and the emergence of walled sites in late Neolithic Central Plains of China: Integrating archaeological and geoarchaeological evidence from the Guchengzhai site

The emergence of many late-Neolithic and early Bronze-Age walled sites on China's Central Plains coincided with some prominent Holocene climate events. Recent excavation and geoarchaeological investigation at one of the largest walled sites of Guchengzhai provide important data to examine some of the questions concerning the long-term relationship between the formation of aquatic landscape and social evolution in late prehistoric Central Plains. We collected fine-grained paleo-environmental and archaeological evidence from a range of on- and off-site contexts to reconstruct the late-Holocene paleo-environment surrounding the walled site, and examine the construction, maintenance and abandonment processes of its large-size moat. Our results show that there existed many small-to-large-sized waterbodies during the late Holocene, which, together with local rivers, were the main source of water to the site. The Guchengzhai population was drawn to the low-lying land near the river and other waterbodies with an optimal hydrological condition. During its use, the moat might have been linked to the nearby wetlands and/or rivers. The hydrological regime was dominated by gentle but relatively sediment-laden flow, being punctuated by several high-energy flood events. The sedimentation of light yellowish silt and sand with some anthropogenic inclusions during the use of the moat gave way to a quick siltation with the deposition of rich organic matter when the moat ceased to function as a main channel for water flow, although other land-use activities such as fire (land clearance?) continued to occur in the vicinity. The reconstructed ‘life-history’ of the moat demonstrates the increasingly acute challenge facing the growing population living at Guchengzhai as the climate was becoming drier. The construction and operation of the moat signified technological innovations and intensified water management at Guchengzhai, which led to the formation of distinctive aquatic landscape that featured large-scale hydraulic infrastructures in a hydrologically optimal environment. We contend that such was a common characteristic or trend shared by many contemporary or later-period walled sites on the Central Plains

Max-Min Fairness of Rate-Splitting Multiple Access with Finite Blocklength Communications

Rate-Splitting Multiple Access (RSMA) has emerged as a flexible and powerful framework for wireless networks. In this paper, we investigate the user fairness of downlink multi-antenna RSMA in short-packet communications with/without cooperative (user-relaying) transmission. We design optimal time allocation and linear precoders that maximize the Max-Min Fairness (MMF) rate with Finite Blocklength (FBL) constraints. The relation between the MMF rate and blocklength of RSMA, as well as the impact of cooperative transmission are investigated for a wide range of network loads. Numerical results demonstrate that RSMA can achieve the same MMF rate as Non-Orthogonal Multiple Access (NOMA) and Space Division Multiple Access (SDMA) with smaller blocklengths (and therefore lower latency), especially in cooperative transmission deployment. Hence, we conclude that RSMA is a promising multiple access for guaranteeing user fairness in low-latency communications.Comment: arXiv admin note: text overlap with arXiv:2105.0619

4K-Resolution Photo Exposure Correction at 125 FPS with ~8K Parameters

The illumination of improperly exposed photographs has been widely corrected using deep convolutional neural networks or Transformers. Despite with promising performance, these methods usually suffer from large parameter amounts and heavy computational FLOPs on high-resolution photographs. In this paper, we propose extremely light-weight (with only ~8K parameters) Multi-Scale Linear Transformation (MSLT) networks under the multi-layer perception architecture, which can process 4K-resolution sRGB images at 125 Frame-Per-Second (FPS) by a Titan RTX GPU. Specifically, the proposed MSLT networks first decompose an input image into high and low frequency layers by Laplacian pyramid techniques, and then sequentially correct different layers by pixel-adaptive linear transformation, which is implemented by efficient bilateral grid learning or 1x1 convolutions. Experiments on two benchmark datasets demonstrate the efficiency of our MSLTs against the state-of-the-arts on photo exposure correction. Extensive ablation studies validate the effectiveness of our contributions. The code is available at https://github.com/Zhou-Yijie/MSLTNet.Comment: WACV202

CLIP Brings Better Features to Visual Aesthetics Learners

The success of pre-training approaches on a variety of downstream tasks has revitalized the field of computer vision. Image aesthetics assessment (IAA) is one of the ideal application scenarios for such methods due to subjective and expensive labeling procedure. In this work, an unified and flexible two-phase \textbf{C}LIP-based \textbf{S}emi-supervised \textbf{K}nowledge \textbf{D}istillation paradigm is proposed, namely \textbf{\textit{CSKD}}. Specifically, we first integrate and leverage a multi-source unlabeled dataset to align rich features between a given visual encoder and an off-the-shelf CLIP image encoder via feature alignment loss. Notably, the given visual encoder is not limited by size or structure and, once well-trained, it can seamlessly serve as a better visual aesthetic learner for both student and teacher. In the second phase, the unlabeled data is also utilized in semi-supervised IAA learning to further boost student model performance when applied in latency-sensitive production scenarios. By analyzing the attention distance and entropy before and after feature alignment, we notice an alleviation of feature collapse issue, which in turn showcase the necessity of feature alignment instead of training directly based on CLIP image encoder. Extensive experiments indicate the superiority of CSKD, which achieves state-of-the-art performance on multiple widely used IAA benchmarks

Antitumor effect of a pyrazolone-based complex [Cu(PMPP-SAL)(EtOH)] against murine melanoma B16 cell in vitro and in vivo

Pyrazolone-based derivative metal complexes were reported to have cytotoxicity in some tumor cells. In this study, the antitumor effect of [Cu(PMPP-SAL)(EtOH)] (PMPP-SAL = N-(1-phenyl-3-methyl-4-propenylidene-5-pyrazolone)-salicylidene hydrazide anion) in murine melanoma B16 cells in vitro and in vivo was investigated. The result showed that [Cu(PMPP-SAL)(EtOH)] inhibited the survival of B16 cells in vitro, and the IC50 value was superior to cisplatin (DDP) (p < 0.001). B16 cell apoptosis was significantly higher in comparison to the control group (DMSO) (p < 0.01), and cell cycle arrest occurred at the G0/G1 phase. When challenged C57 BL/6J mice were treated with [Cu(PMPP-SAL)(EtOH)], a smaller volume of B16 solid tumors were reported than the control group (p < 0.01), with lower positive expression indices of CD 34, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) (p < 0.01). Moreover, the tumor growth was suppressed in mice due to the induction of apoptosis, as detected by the TUNEL assay (p < 0.001). In summary, [Cu(PMPP-SAL)(EtOH)] effectively inhibited the growth of B16 cells in vitro and in vivo due to the induction of apoptosis and the inhibition of intra-tumoral angiogenesis, demonstrating its therapeutic potential in melanoma treatment

Rate-Splitting Multiple Access for Simultaneous Multi-User Communication and Multi-Target Sensing

In this paper, we initiate the study of rate-splitting multiple access (RSMA) for a mono-static integrated sensing and communication (ISAC) system, where the dual-functional base station (BS) simultaneously communicates with multiple users and detects multiple moving targets. We aim at optimizing the ISAC waveform to jointly maximize the max-min fairness (MMF) rate of the communication users and minimize the largest eigenvalue of the Cram\'er-Rao bound (CRB) matrix for unbiased estimation. The CRB matrix considered in this work is general as it involves the estimation of angular direction, complex reflection coefficient, and Doppler frequency for multiple moving targets. Simulation results demonstrate that RSMA maintains a larger communication and sensing trade-off than conventional space-division multiple access (SDMA) and it is capable of detecting multiple targets with a high detection accuracy. The finding highlights the potential of RSMA as an effective and powerful strategy for interference management in the general multi-user multi-target ISAC systems