108 research outputs found

    An Explanation of Energy Return on Investment From an Entropy Perspective

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    Low-carbon energy transformation is a major trend in world energy development, and measures to mitigate carbon emissions can vary substantially in terms of the energy they require. A common method of evaluating energy use in energy resource exploitation is energy return on investment (EROI). One of the criticisms of EROI concerns uncertainty regarding the input and output factors for the calculation. To make the issue clear, we interpret EROI in terms of entropy, which is the most basic concept in physics. We consider an energy resource exploitation system to be a kind of dissipative structure and construct a basic entropy analysis framework for an energy resource exploitation system. We then derive the relationship between EROI and entropy change. The theory of EROI is consistent with the basic requirement for a dissipative structure, which is that the total entropy change must be negative. EROI is a method of using entropy theory to evaluate energy resource exploitation. It is inappropriate and unnecessary to quantify all factors as energy units as the input and output factors are multidimensional while energy is a one-dimensional standard. Future development of the EROI method should be guided by entropy theory. A series of EROI related indicators will increase its application and policy significance

    Chemical synthesis and characterization of zinc borohydride

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    AbstractMetal borohydrides have received increasing research interests on account of their high hydrogen storage capacities. In this paper, zinc borohydride Zn(BH4)2 was synthesized using NaBH4 and ZnCl2 in THF under room temperature for 72h, and the crystallographic constitution of the synthesized products were analyzed by XRD. The results showed that the major phase of the products was NaCl, alternatively, NaBH4 or ZnCl2 disappeared. This concluded the formation of Zn(BH4)2. Moreover, both experiment phenomena and fired products further confirmed the synthesis of Zn(BH4)2, which a XRD pattern of Zinc borohydride was obtained

    A nanogapped hysteresis-free field-effect transistor

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    We propose a semi-suspended device structure and construct nanogapped, hysteresis-free field-effect transistors (FETs), based on the van der Waals stacking technique. The structure, which features a semi-suspended channel above a submicron-long wedge-like nanogap, is fulfilled by transferring ultraclean BN-supported MoS2_2 channels directly onto dielectric-spaced vertical source/drain stacks. Electronic characterization and analyses reveal a high overall device quality, including ultraclean channel interfaces, negligible electrical scanning hysteresis, and Ohmic contacts in the structures. The unique hollow FET structure holds the potential for exploiting reliable electronics, as well as nanofluid and pressure sensors.Comment: 22 pages, 4 figures, with S

    Minimally invasive surgery vs. open thoracotomy for non-small-cell lung cancer with N2 disease: a systematic review and meta-analysis

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    BackgroundThis meta-analysis aimed to investigate the effectiveness and safety of minimally invasive surgery [MIS, including robotic-assisted thoracoscopic surgery (RATS) and video-assisted thoracoscopic surgery (VATS)] and open thoracotomy (OT) for non-small cell lung cancer (NSCLC) patients with N2 disease.MethodsWe searched online databases and studies from the creation of the database to August 2022, comparing the MIS group to the OT group for NSCLC with N2 disease. Study endpoints included intraoperative outcomes [e.g., conversion, estimated blood loss (EBL), surgery time (ST), total lymph nodes (TLN), and R0 resection], postoperative outcomes [e.g., length of stay (LOS) and complication], and survival outcomes [e.g., 30-day mortality, overall survival (OS), and disease-free survival (DFS)]. We estimated outcomes using random effects meta-analysis to account for studies with high heterogeneity (I2 > 50 or p < 0.05). Otherwise, we used a fixed-effect model. We calculated odds ratios (ORs) for binary outcomes and standard mean differences (SMDs) for continuous outcomes. Treatment effects on OS and DFS were described by hazard ratio (HR).ResultsThis systematic review and meta-analysis of 15 studies on MIS vs. OT for NSCLC with N2 disease included 8,374 patients. Compared to OT, patients that underwent MIS had less estimated blood loss (EBL) (SMD = – 64.82, p < 0.01), shorter length of stay (LOS) (SMD = −0.15, p < 0.01), higher R0 resection rate (OR = 1.22, p = 0.049), lower 30-day mortality (OR = 0.67, p = 0.03), and longer overall survival (OS) (HR = 0.61, P < 0.01). The results showed no statistically significant differences in surgical time (ST), total lymph nodes (TLN), complications, and disease-free survival (DFS) between the two groups.ConclusionCurrent data suggest that minimally invasive surgery may provide satisfying outcomes, a higher R0 resection rate, and better short-term and long-term survival than open thoracotomy.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022355712

    Chemical composition of Chinese palm fruit and chemical properties of the oil extracts

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    The proximate composition, mineral concentration of fleshy mesocarp, palm meat (PM) and palm kernel (PK) of oil palm fruit (Elaeis guineensis S.L.Dura) produced in Hainan, China were investigated. The fatty acid composition, chemical properties and minor constituents of palm oil (PO) and palm kernel oil (PKO) were also studied. The crude fat of PM and PK were 68.09±3.57% and 49.36±2.61%, respectively. The PM and PK were found to be good sources of minerals. The acid value (AV) and free fatty acid (FFA) of PO extracted from fresh PM were much higher. If the fresh PM were heated at 100ºC for 30 min, the AV and % FFA could be reduced to 4.62±0.04 mgKOH/g and 2.72±0.002%, respectively. The major fatty acid of PO was palmitic acid 39.93±1.66% and that of PKO was lauric acid 48.01±0.69%. Tocopherol isomer (α-, (β+γ)- and δ-) contents in PO were 68.8±1.84, 22.8±0.54 and 11.8±0.12 mg/kg, respectively. The β-carotene content in PO was 901.5±11.95 mg/kg. The content of sterols in PO and PKO were 880.0±5.23 and 858.0±4.37 mg/kg, respectively. PO and PKO exhibited good chemical properties and could be used as edible oils and for industrial applications. There are almost no data about Chinese palm fruit now and this study systematically researched on it, which can provide useful information for Chinese oil palm industry.Key words: Chemical composition, palm fruit, palm oil, palm kernel oil, chemical properties

    Hierarchical Interaction Networks with Rethinking Mechanism for Document-level Sentiment Analysis

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    Document-level Sentiment Analysis (DSA) is more challenging due to vague semantic links and complicate sentiment information. Recent works have been devoted to leveraging text summarization and have achieved promising results. However, these summarization-based methods did not take full advantage of the summary including ignoring the inherent interactions between the summary and document. As a result, they limited the representation to express major points in the document, which is highly indicative of the key sentiment. In this paper, we study how to effectively generate a discriminative representation with explicit subject patterns and sentiment contexts for DSA. A Hierarchical Interaction Networks (HIN) is proposed to explore bidirectional interactions between the summary and document at multiple granularities and learn subject-oriented document representations for sentiment classification. Furthermore, we design a Sentiment-based Rethinking mechanism (SR) by refining the HIN with sentiment label information to learn a more sentiment-aware document representation. We extensively evaluate our proposed models on three public datasets. The experimental results consistently demonstrate the effectiveness of our proposed models and show that HIN-SR outperforms various state-of-the-art methods.Comment: 17 pages, accepted by ECML-PKDD 202

    Effect of Mild Heating Assisted Alkaline pH Shift Treatment on the Structural and Functional Properties of Porcine Liver Protein

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    In this study, a combined method of physical and chemical modification was used to improve the functional characteristics of porcine liver protein (PLP). PLP was modified by mild heating assisted alkaline pH shift treatment. The hydration properties, surface properties, particle size distribution, denaturation degree and molecular structure of modified PLP were measured. The results showed that heat treatment combined with a large shift in pH toward the alkaline side significantly increased the solubility and emulsifying activity of PLP, reduced the particle size while resulting in uniform size distribution, increased the absolute value of zeta potential, and decreased the free sulfhydryl content, changed the primary, secondary and tertiary structures, and increased the surface hydrophobicity. The combined treatment was superior to either treatment alone. In terms of improvements in the hydration and surface properties of PLP, heating at 50 ℃ combined with pH shift toward pH 11 was the best modification condition for PLP
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