224 research outputs found

    A conceptional approach of resin-transfer-molding to rosin-sourced epoxy matrix green composites†

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    In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites

    A review of research on acoustic detection of heat exchanger tube

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    Leakage in heat exchanger tubes can result in unreliable products and dangerous situations, which could cause great economic losses. Along with fast development of modern acoustic detection technology, using acoustic signals to detect leakage in heat exchange tube has been gradually accepted and considered with great potential by both industrial and research societies. In order to further advance the development of acoustic signal detection technology and investigate better methods for leakage detection in heat exchange tube, in this paper, firstly, we conduct a short overview of the theory of acoustic signal detection on heat exchanger tube, which had already been continuously developed for a few decades by researchers worldwide. Thereafter, we further expound the advantages and limitations of acoustic signal detection technology on heat exchanger tube in four aspects: 1) principles of acoustic signal detection, 2) characteristics of sound wave propagation in heat exchanger tube, 3) methods of leakage detection, and 4) leakage localization in heat exchanger tube

    ChatEDA: A Large Language Model Powered Autonomous Agent for EDA

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    The integration of a complex set of Electronic Design Automation (EDA) tools to enhance interoperability is a critical concern for circuit designers. Recent advancements in large language models (LLMs) have showcased their exceptional capabilities in natural language processing and comprehension, offering a novel approach to interfacing with EDA tools. This research paper introduces ChatEDA, an autonomous agent for EDA empowered by a large language model, AutoMage, complemented by EDA tools serving as executors. ChatEDA streamlines the design flow from the Register-Transfer Level (RTL) to the Graphic Data System Version II (GDSII) by effectively managing task planning, script generation, and task execution. Through comprehensive experimental evaluations, ChatEDA has demonstrated its proficiency in handling diverse requirements, and our fine-tuned AutoMage model has exhibited superior performance compared to GPT-4 and other similar LLMs

    Effect of Spatholobus suberectus (Fabaceae) extract on second-degree burns in rats

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    Purpose: To evaluate the wound-healing effect of Spatholobus suberectus (Fabaceae) on seconddegree burns in a rat model.Methods: The animals were divided into normal, negative control, as well as 10 % Spatholobus suberectus (SS) (SS10), 20 % SS (SS20) and standard (STD) groups. Second-degree burns were inflicted by exposing a 3 × 3 cm sterile area of skin to boiling water for 10 min. The animals were treated topically twice daily for 2 weeks. Wound contraction (%) was measured after 2 weeks, while wound tissue  histopathology was assessed by hematoxylin & eosin and Masson’s trichrome staining. In addition, lipid peroxidation (malondialdehyde kit) and cytokine secretion (ELISA) were measured in liver and plasma, respectively.Results: The results of this study suggest that topical application of SS for 2 weeks significantly increases wound closure compared with the negative control. Moreover, treatment with SS significantly improved the pathological status of the wound throughout the protocol. There was also a significant decrease in malondialdehyde activity and increase in cytokine release in SS-treated rats compared with control rats.Conclusions: The results show that topical application of SS after inflicting second-degree burns in rats results in increased wound healing and decreased cytokine release and oxidative stress.Keyword: Spatholobus suberectus, Burns, Wound, Lipid peroxidation, Cytokine

    An energy balance and mobility prediction clustering algrithm for large-scale UAV ad hoc networks

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    Creating a clustering structure is considered the performance of radio frequency (RF) stealth for data link in the battlefield environment and the dynamic topology characteristic for larger-scale unmanned aerial vehicle (UAV) ad hoc networks. This  problem is of a great importance-to get low intercept probability of the data link and low randomness of clustering structure. An energy balance and mobility prediction (EBMP) clustering algorithm is proposed. In the initial clustering stage, the power management for information transmission is conducted in the network layer and the MAC layer. The Doppler shift is implemented to estimate the relative speeds stability degree between neighboring UAVs when they exchange Hello packets. It can be selected as cluster head (CH) where  one UAV associateslower energy consumption with  higher relative stability. In the cluster maintaining stage, a CH rotation process for the dynamic topology to improve resource utilization efficiency. The inter-cluster communication is enhanced by dynamic packet forwarding gateway. The simulations and analysis show that this scheme can provide better results for larger-scale UAV ad hoc networks compared to MPBC and MPCR in terms of improving CH lifetime and throughput, reducing average delay

    Two-stage association study to identify the genetic susceptibility of a novel common variant of rs2075290 in ZPR1 to type 2 diabetes

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    The SNP of rs964184 in ZPR1 has recently been associated with type 2 diabetes mellitus (T2DM) in Japanese individuals. To comprehensively investigate the association of common variants in ZPR1 with T2DM in Han Chinese individuals, we designed a two-stage case-control study of 3,505 T2DM patients and 6,911 unrelated healthy Han Chinese individuals. A total of 24 single nucleotide polymorphisms (SNPs) were genotyped, and single-SNP association, imputation and gender-specific association analyses were performed. To increase the coverage of genetic markers, we implemented imputation techniques to extend the number of tested makers to 280. A novel SNP, rs2075290, and the previously reported SNP, rs964184, were significantly associated with T2DM in the two independent datasets, and individuals harboring the CC genotype of rs2075290 and GG genotype of rs964184 exhibited higher levels of fasting plasma glucose (FPG) and blood hemoglobin A1c (HbA1c) than individuals of other genotypes. Additionally, haplotype analyses indicated that two haplotype blocks containing rs2075290 or rs964184 were also significantly associated with T2DM. In summary, these results suggest that ZPR1 plays an important role in the etiology of T2DM, and this gene might be involved in abnormal glucose metabolism

    Insulin Resistance and Oxidative Stress: In Relation to Cognitive Function and Psychopathology in Drug-Naive, First-Episode Drug-Free Schizophrenia

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    Objective: The present study aimed to examine whether insulin resistance and oxidative stress are associated with cognitive impairment in first-episode drug-free schizophrenia (SZ) patients. Methods: Ninety first-episode SZ patients and 70 healthy controls were enrolled. Fasting insulin (FINS) and markers of oxidative stress [oxidized glutathione (GSSG), superoxide dismutase (SOD), nitric oxide (NO) and uric acid (UA) levels] were measured in serum before pharmacological treatment was initiated. Psychiatric symptoms and cognitive function were assessed with the Positive and Negative Syndrome Scale (PANSS) and MATRICS Consensus Cognitive Battery (MCCB), respectively. In addition, the homeostatic model assessment of insulin resistance (HOMA-IR) was also studied. Results: HOMA-IR and serum levels of GSSG and NO were significantly higher in SZ patients than in healthy controls (P \u3c 0.001), while the serum levels of SOD were significantly lower than in healthy controls (P \u3c 0.001). HOMA-IR, GSSG and NO levels were significantly correlated to the total cognitive function scores of the patient group (r = -0.345,-0.369,-0.444, respectively, P \u3c 0.05). But these factors were not co-related to the cognitive functions in the healthy control group. And, levels of SOD, UA were not associated with the total cognitive function scores in both the patient and the healthy control groups. NO was positively correlated with general pathological and the total score in the PANSS, and was negatively correlated with six cognitive domains (r = -0.316 to -0.553, P \u3c 0.05). Conclusions: The levels of insulin resistance and oxidative stress are elevated, and correlated with the severity of cognitive impairment in drug-naive, first-episode SZ patients. Treatment approaches targeting on reducing insulin resistance and oxidative stress may improve cognitive function in SZ patients

    Cryogenic quasi-static embedded DRAM for energy-efficient compute-in-memory applications

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    Compute-in-memory (CIM) presents an attractive approach for energy-efficient computing in data-intensive applications. However, the development of suitable memory designs to achieve high-performance CIM remains a challenging task. Here, we propose a cryogenic quasi-static embedded DRAM to address the logic-memory mismatch of CIM. Guided by the re-calibrated cryogenic device model, the designed four-transistor bit-cell achieves full-swing data storage, low power consumption, and extended retention time at cryogenic temperatures. Combined with the adoption of cryogenic write bitline biasing technique and readout circuitry optimization, our 4Kb cryogenic eDRAM chip demonstrates a 1.37×\times106^6 times improvement in retention time, while achieving a 75 times improvement in retention variability, compared to room-temperature operation. Moreover, it also achieves outstanding power performance with a retention power of 112 fW and a dynamic power of 108 μ\muW at 4.2 K, which can be further decreased by 7.1% and 13.6% using the dynamic voltage scaling technique. This work reveals the great potential of cryogenic CMOS for high-density data storage and lays a solid foundation for energy-efficient CIM implementations

    Interplay between moment-dependent and field-driven unidirectional magnetoresistance in CoFeB/InSb/CdTe heterostructures

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    Magnetoresistance effects are crucial for understanding the charge/spin transport as well as propelling the advancement of spintronic applications. Here we report the coexistence of magnetic moment-dependent (MD) and magnetic field-driven (FD) unidirectional magnetoresistance (UMR) effects in CoFeB/InSb/CdTe heterostructures. The strong spin-orbital coupling of InSb and the matched impedance at the CoFeB/InSb interface warrant a distinct MD-UMR effect at room temperature, while the interaction between the in-plane magnetic field and the Rashba effect at the InSb/CdTe interface induces the marked FD-UMR signal that dominates the high-field region. Moreover, owning to the different spin transport mechanisms, these two types of nonreciprocal charge transport show opposite polarities with respect to the magnetic field direction, which further enable an effective phase modulation of the angular-dependent magnetoresistance. Besides, the demonstrations of both the tunable UMR response and two-terminal spin-orbit torque-driven magnetization switching validate our CoFeB/InSb/CdTe system as a suitable integrated building block for multifunctional spintronic device design
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