State-of-the-Art Analysis and Perspectives for Peer-to-Peer Energy Trading

As a promising solution to address the“energy trilemma”confronting human society,peer-to-peer(P2P)energy trading has emerged and rapidly developed in recent years.When carrying out P2P energy trading,customers with distributed energy resources(DERs)are able to directly trade and share energy with each other.This paper summarizes and analyzes the global development of P2P energy trading based on a comprehensive review of related academic papers,research projects,and industrial practice.Key aspects in P2P energy trading are identified and discussed,including market design,trading platforms,physical infrastructure and information and communication technology(ICT)infrastructure,social science perspectives,and policy.For each key aspect,existing research and practice are critically reviewed and insights for future development are presented.Comprehensive concluding remarks are provided at the end,summarizing the major findings and perspectives of this paper.P2P energy trading is a growing field with great potential and opportunities for both academia and industry across the world.

An Overview of the Smart Grid in Great Britain

This paper presents an overview of the current status of the development of the smart grid in Great Britain(GB).The definition,policy and technical drivers,incentive mechanisms,technological focus,and the industry's progress in developing the smart grid are described.In particular,the Low Carbon Networks Fund and Electricity Network Innovation Competition projects,together with the rollout of smart metering,are detailed.A more observable,controllable,automated,and integrated electricity network will be supported by these investments in conjunction with smart meter installation.It is found that the focus has mainly been on distribution networks as well as on real-time flows of information and interaction between suppliers and consumers facilitated by improved information and communications technology,active power flow management,demand management,and energy storage.The learning from the GB smart grid initiatives will provide valuable guidelines for future smart grid development in GB and other countries.

Computational screening and design of nanoporous membranes for efficient carbon isotope separation

Stable isotopes have been routinely used in chemical sciences,medical treatment and agricultural research.Conventional technologies to produce high-purity isotopes entail lengthy separation processes that often suffer from low selectivity and poor energy efficiency.Recent advances in nanoporous materials open up new opportunities for more efficient isotope enrichment and separation as the pore size and local chemical environment of such materials can be engineered with atomic precision.In this work,we demonstrate the unique capability of nanoporous membranes for the separation of stable carbon isotopes by computational screening a materials database consisting of 12,478 computation-ready,experimental metal-organic frameworks(MOFs).Nanoporous materials with the highest selectivity and membrane performance scores have been identified for separation of^(12)CH_4/^(13)CH_4 at the ambient condition(300 K).Analyzing the structural features and metal sites of the promising MOF candidates offers useful insights into membrane design to further improve the performance.An upper limit of the efficiency has been identified for the separation of^(12)CH_4/^(13)CH_4 with the existing MOFs and those variations by replacement of the metal sites.

An improved theoretical procedure for the pore-size analysis of activated carbon by gas adsorption

Amorphous carbon materials play a vital role in adsorbed natural gas(ANG) storage. One of the key issues in the more prevalent use of ANG is the limited adsorption capacity, which is primarily determined by the porosity and surface characteristics of porous materials. To identify suitable adsorbents, we need a reliable computational tool for pore characterization and, subsequently, quantitative prediction of the adsorption behavior. Within the framework of adsorption integral equation(AIE), the pore-size distribution(PSD) is sensitive to the adopted theoretical models and numerical algorithms through isotherm fitting. In recent years, the classical density functional theory(DFT) has emerged as a common choice to describe adsorption isotherms for AIE kernel construction. However,rarely considered is the accuracy of the mean-field approximation(MFA) commonly used in commercial software. In this work, we calibrate four versions of DFT methods with grand canonical Monte Carlo(GCMC) molecular simulation for the adsorption of CH_4 and CO_2 gas in slit pores at 298 K with the pore width varying from 0.65 to 5.00 nm and pressure from 0.2 to 2.0 MPa. It is found that a weighted-density approximation proposed by Yu(WDA-Yu) is more accurate than MFA and other non-local DFT methods. In combination with the trapezoid discretization of AIE, the WDA-Yu method provides a faithful representation of experimental data, with the accuracy and stability improved by 90.0% and 91.2%, respectively, in comparison with the corresponding results from MFA for fitting CO_2 isotherms. In particular, those distributions in the feature pore width range(FPWR)are proved more representative for the pore-size analysis. The new theoretical procedure for pore characterization has also been tested with the methane adsorption capacity in seven activated carbon samples.

Prognostic significance of PD-L1 expression in patients with colorectal cancer: a meta-analysis

Background The association between the expression of programmed cell death 1(PD-1) or its ligand [programmed cell death ligand-1(PD-L1)] and colorectal cancer(CRC) survival rates remains unclear. Thus, we conducted a meta-analysis to investigate the prognostic value of PD-L1 expression in CRC patients.Methods All eligible studies related to evaluation of PD-L1 expression and survival of CRC patients were searched in PubMed, Medline, Cochrane library, and the EMBASE database. Hazard ratios(HRs) and 95% confidence intervals(CI) of overall survival(OS) were examined to assess the effect of PD-L1 expression on the survival of CRC patients. The outcomes of this meta-analysis were synthesized based on randomeffects model. Subgroup analyses were also performed. Results Seven studies, wherein OS data were stratified according to the expression status of PD-L1, were analyzed. CRC patients showing positive PD-L1 expression were associated with significantly poorer prognoses in terms of overall survival, compared with those displaying negative PD-L1 expression(HR = 1.43, 95% CI: 1.07–1.92; P = 0.02). In the subgroup analyses, H-scores as well as the percentage of stained cells indicated that PD-L1 expression was significantly associated with poor prognosis(HR = 1.90, 95% CI: 1.38–2.62, P < 0.01; HR = 1.81, 95% CI: 1.08–3.03, P = 0.02). Immunohistochemical staining, utilizing a rabbit anti-PD-L1 antibody, revealed significantly superior survival in the PD-L1 negative group compared with the PD-L1 positive expression group(HR = 1.92; 95% CI, 1.40-2.63; P < 0.01). Moreover, PD-L1 expression was significantly associated with poor prognosis when polyclonal antibodies were used(HR = 1.84; 95% CI, 1.30–2.61; P < 0.01). Conclusion Our meta-analysis indicated that PD-L1 expression status is a significant prognostic factor for CRC patients. Positive PD-L1 expression was associated with worse CRC survival. Evaluation via different immunohistochemistry based techniques may partly account for the contradictory results. Therefore, further investigative studies using larger sample sizes are felt to be needed to elucidate the prognostic value of PD-L1 expression in CRC patients.

Effect of <i>Monascus</i>Fermentation on Aroma Patterns of Semi-Dried Grass Carp

The aim of the present study is to investigate the effects of Monascus fermentation on the aroma pattern of semi-dried grass carp. Semi-dried fish was fermented using Monascus purpureus GDMCC3.439. The volatile flavor substances present in fresh fish, semi-dry fish and Monascus fermented semi-dried fish were compared by simultaneous distillation and extraction combined with gas chromatograph-mass spectrometer (GC-MS). The results showed that alcohols, aldehydes and ketones were the main components of the flavor of the unfermented and fermented semi-dried grass crap. Monascus fermentation could significantly affect the volatile flavor substances of semi-dried grass carp. Moreover, the processing of semi-dried fish fermented by Monascus could not only effectively improve the fishy smell of fresh fish, but also make up for the defect of the pickled flavor of semi-dried fish. Eighteen of the main volatile components in semi-dried fish fermented by Monascus were identified by relative odor activity value (ROAV), as follows: 1-octene-3-ol, phenylethanol, hexanal, heptanal, nonanal, (E)-2-octenal, 3-Methyl-1-butanal, benzaldehyde, (E)-2-nonenal, (E,E)-2,4-heptadienal, (E)-2-Decenal, phenylacetaldehyde, (E,E)-2.4-decadienal, tetradecanal, 2,3-butanone, 2,3-octanedione, alpha-pinene, 2-pentane furan.

Feasibility Study of Flotation Process in Separating Chicken from Chicken Skeleton

An innovative and effective method of separating chicken meat and bone from chicken skeleton was developed in this study. Different heating approaches to chicken skeleton were compared to optimize cooking conditions including cooking temperature and cooking time. The separation efficiency of chicken meat and bone in different conditions, including flow direction, impeller speed and the liquid level rising velocity were also studied. Experimental results demonstrated high temperature cooking and assisted mechanical stirring could improve separating rate of chicken skeleton. Liquid flow entering at tangent entrance direction of the kettle could maintain the stability of the liquid level and smoothness of the separation process. The outflow rate of chicken meat increased as the liquid level rising velocity raised, and approached to the maximum value at 0.80 cm/s. The practical application test showed that the best conditions for separation of chicken skeleton were: 45 min cooking time at 114°C;tangent flow direction;stir speed of 200 r/min;the liquid level rising velocity of water is 0.8 cm/s. Using this approach, the value of chicken bone was increased, product specialization was enhanced, and the results could be used in future high value chicken product development.

Theoretical insights on the hydration of quinones as catholytes in aqueous redox flow batteries

Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.

Curvature effects on electric-double-layer capacitance

Understanding the microscopic structure and thermodynamic properties of electrode/electrolyte interfaces is central to the rational design of electric-double-layer capacitors(EDLCs).Whereas practical applications often entail electrodes with complicated pore structures,theoretical studies are mostly restricted to EDLCs of simple geometry such as planar or slit pores ignoring the curvature effects of the electrode surface.Significant gaps exist regarding the EDLC performance and the interfacial structure.Herein the classical density functional theory(CDFT)is used to study the capacitance and interfacial behavior of spherical electric double layers within a coarse-grained model.The capacitive performance is associated with electrode curvature,surface potential,and electrolyte concentration and can be correlated with a regression-tree(RT)model.The combination of CDFT with machine-learning methods provides a promising quantitative framework useful for the computational screening of porous electrodes and novel electrolytes.

Recent progress in enzymatic functionalization of carbon-hydrogen bonds for the green synthesis of chemicals

Enzymatic reactions take place with high chemo-, regio-, and stereo-selectivity, appealing for the direct functionalization of abundant and inexpensive compounds with C-H bonds to make fine chemicals such as high-value intermediates and pharmaceuticals. This review summarizes recent progress in the enzymatic functionalization of C-H bonds with an emphasis on heme enzymes such as cytochrome P450 s, chloroperoxidase and unspecific peroxygenases. Specific examples are discussed to elucidate the applications of the molecular and process engineering approaches to overcome the challenges hindering enzymatic C-H functionalization. Also discussed is the recent development of the chemo-enzymatic cascade as an effective way to integrate the power of metal catalysis and enzymatic catalysis for C-H functionalization.

A Special Issue:“Optimization and Key Equipments of Integrated Energy System”for Global Energy Interconnection

Energy is a critical basis for the survival and progress of humanity.Traditional energy systems,which are planned,designed,and operated in isolation,have artificially disrupted the interconnections among various energy forms.This limitation has reduced the reliability and flexibility of system operations,rendering them unsuitable for societal advancement.Integrated energy systems(IESs)dismantle the technical,market,and managerial barriers inherent in traditional systems.

Safety and efficacy of EFGR and VEGF signaling pathway inhibition therapy in patients with colorectal cancer: a meta-analysis

Objective Epidermal growth factor receptor(EGFR) and vascular endothelial growth factor(VEGF) inhibitors are two targeted therapies for metastatic colorectal cancer(mCRC). However, few studies have focused on the safety and efficacy of combined targeted therapy against those of a single inhibition therapy of EFGR or VEGF. This meta-analysis aimed to compare the anti-tumor activity of the combined inhibition therapy and single inhibition therapy in patients with mCRC. Methods We searched PubMed, Medline, the Cochrane library, Embase, and annual meeting proceedings for relevant clinical trials. Objective response rate(ORR), progression-free survival(PFS), overall survival(OS), and adverse events were extracted and calculated.Results Nine trials comprising 3977 patients were selected for the analysis. The combined inhibition therapy showed a 3.7% improvement in ORR compared with single inhibition, and this difference was statistically significant [hazard ratio(HR) = 1.33; 95% confidence interval(CI), 1.01–1.74; P = 0.04]. Subgroup analysis showed that the combined EGFR and VEGF inhibitor therapy had an 11.65% improvement in ORR compared with VEGF inhibitor therapy(OR = 2.14; 95% CI, 1.34–3.40; P = 0.001). EGFR and VEGF inhibitor therapy and chemotherapy had an 18.08% improvement in ORR compared with chemotherapy(OR = 2.21; 95% CI, 1.05–4.64; P = 0.04). Moreover, EGFR and VEGF inhibitor therapy significantly improved PFS compared with VEGF inhibitor therapy(OR = 0.82; 95% CI, 0.69–0.97; P = 0.02). VEGF inhibitor therapy and chemotherapy significantly improved PFS compared with EGFR and VEGF inhibitor therapy and chemotherapy(OR = 1.20; 95% CI, 1.11–1.30; P = 0.00). In addition, EGFR and VEGF inhibitor therapy showed improved OS compared with VEGF inhibitor therapy(HR = 0.78, 95% CI: 0.65–0.94; P = 0.008). Finally, the combined inhibition therapy showed an obviously increased risk of cutaneous and mucosal effects(RR = 6.45; 95% CI: 2.71–15.36; P < 0.01), diarrhea/abdominal pain(RR = 1.97; 95% CI: 1.45–2.68; P < 0.01), fatigue/asthenia(RR = 1.60; 95% CI: 1.10–2.32; P = 0.01), dehydration or electrolyte disturbance(RR = 2.78; 95% CI: 1.48–5.21; P < 0.01), nail disorder(RR = 8.23; 95% CI: 1.52–44.57; P = 0.01), and dizziness/headache(RR = 3.43; 95% CI: 1.89–6.23; P < 0.01) compared with single inhibition therapy.Conclusion Compared with single inhibition therapy, the combined inhibition therapy significantly improved ORR, PFS, and OS in the treatment of mCRC patients. Compared with a single-targeted agent, the combined therapy of anti-EGFR and anti-VEGF drug provided an efficacy advantage, although it led to greater toxicity.

Microscopic principles of chemical engineering after fossil fuels

Chemical engineering is a broad field in terms of the scope of practice but the discipline has been united by a few intellectually coherent principles. Among them, thermodynamics, reaction kinetics and transport phenomena are often considered as the cornerstones, providing support for the design and operation of diverse chemical processes for power generation and production of industrial goods such as plastics, gasoline and ammonia. Traditionally, these industrial processes use fossil fuels as the raw materials and are responsible for significant greenhouse gas emissions. As fossil-energy-based processes are deemed phasing out , development of alternative routes with renewable energy and sustainable feedstock is calling for the expansion of the knowledge base such that eco-friendly chemical processes can be quantified, controlled and optimized with high precision. This article offers some perspectives on possible engineering developments to accelerate the paradigm shift from fossil fuels to renewable energy.

Data-driven Predictive Voltage Control for Distributed Energy Storage in Active Distribution Networks

Integration of distributed energy storage(DES)is beneficial for mitigating voltage fluctuations in highly distributed generator(DG)-penetrated active distribution networks(ADNs).Based on an accurate physical model of ADN,conventional model-based methods can realize optimal control of DES.However,absence of network parameters and complex operational states of ADN poses challenges to model-based methods.This paper proposes a data-driven predictive voltage control method for DES.First,considering time-series constraints,a data-driven predictive control model is formulated for DES by using measurement data.Then,a data-driven coordination method is proposed for DES and DGs in each area.Through boundary information interaction,voltage mitigation effects can be improved by interarea coordination control.Finally,control performance is tested on a modified IEEE 33-node test case.Case studies demonstrate that by fully utilizing multi-source data,the proposed predictive control method can effectively regulate DES and DGs to mitigate voltage violations.

Population Genomic Analysis and De Novo Assembly Reveal the Origin of Weedy Rice as an Evolutionary Game

Crop weediness,especially that of weedy rice(Oryza sativa f.spontanea),remains mysterious.Weedy rice possesses robust ecological adaptability;however,how this strain originated and gradually formed proprietary genetic features remains unclear?Here,we demonstrate that weedy rice at Asian high latitudes(WRAH)is phylogenetically well defined and possesses unselected genomic characteristics in many divergence regions between weedy and cultivated rice.We also identified novel quantitative trait loci underlying weedy-specific traits,and revealed that a genome block on the end of chromosome 1 is associated with rice weediness.To identify the genomic modifications underlying weedy rice evolution,we generated the first de novo assembly of a high-quality weedy rice genome(WR04-6),and conducted a comparative genomics study between WR04-6 with other rice reference genomes.Multiple lines of evidence,including the results of demographic scenario comparisons,suggest that differentiation between weedy rice and cultivated rice was initiated by genetic improvement of cultivated rice and that the essence of weediness arose through semi-domestication.A plant height model further implied that the origin of WRAH can be modeled as an evolutionary game and indicated that strategy-based selection driven by fitness shaped its genomic diversity.

Isolation of a Novel Lodging Resistance QTL Gene Involved in Strigolactone Signaling and Its Pyramiding with a QTL Gene Involved in Another Mechanism

Lodging has been a major roadblock to attaining increased crop productivity. In an attempt to understand the mechanism for culm strength in rice, we isolated an effective quantitative trait locus （QTL）, STRONG CULM3 （SCM3）, the causal gene of which is identical to rice TEOSINTE BRANCHED1 （OsTB1）, a gene previously reported to positively control strigolactone （SL） signaling. A near-isogenic line （NIL） carrying SCM3 showed enhanced culm strength and increased spikelet number despite the expected decrease in tiller number, indicating that SL also has a positive role in enhancing culm strength and spikelet number. We produced a pyramiding line carrying SCM3 and SCM2, another QTL encoding AP01 involved in panicle development. The NIL-SCM2＋SCM3 showed a much stronger culm than NIL-SCM2 and NIL-SCM3 and an increased spikelet number caused by the additive effect of these QTLs. We discuss the importance of utilizing suitable alleles of these STRONG CULM QTLs without inducing detrimental traits for breeding.

A preventive control strategy for static voltage stability based on an efficient power plant model of electric vehicles

With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.

Quasi-dynamic Interactions and Security Control of Integrated Electricity and Heating Systems in Normal Operations

Coupling between electricity systems and heating systems are becoming stronger,leading to more flexible and more complex interactions between these systems.The operation of integrated energy systems is greatly affected,especially when security is concerned.Steady-state analysis methods have been widely studied in recent research,which is far from enough when the slow thermal dynamics of heating networks are introduced.Therefore,an integrated quasi-dynamic model of integrated electricity and heating systems is developed.The model combines a heating network dynamic thermal model and the sequential steady-state models of electricity networks,coupling components,and heating network hydraulics.Based on this model,a simulation method is proposed and quasi-dynamic interactions between electricity systems and heating systems are quantified with the highlights of transport delay.Then the quasi-dynamic interactions were applied using security control to relieve congestion in electricity systems.Results show that both the transport delay and control strategies have significant influences on the quasi-dynamic interactions.

Dynamic frequency response from electric vehicles in the Great Britain power system

With the large penetration of renewable energy,fulfilling the balance between electricity demand and supply is a challenge to the modern power system.According to the UK government,the wind power penetration will reach 30%by the year 2020.The role of electric vehicles(EVs)contributing to frequency response was investigated.A dynamic frequency control strategy which considers the comfort level of vehicle owners was developed for EVs to regulate their power consumption according to the deviation of system frequency.A simulation model of a population of EVs equipped with such controlwas implemented inMatlab/Simulink platform.In this paper,a simplified Great Britain power system model is used to study the contribution of EVs to dynamic frequency control.The case study showed that using EVs as a demand response resource can greatly reduce the frequency deviations.And the rapid response from EVs can help reduce the operation cost of conventional generators.

EMTP-type Program Realization of Krylov Subspace Based Model Reduction Methods for Large-Scale Active Distribution Network

Effective model reduction methods are required to deal with new challenges in active distribution network simulations that are on a large scale and have complicated structures.In the development of advanced electromagnetic transient simulation programs,automated model reduction plays an important role.This paper proposes an automated realization algorithm for the Krylov subspace based model reduction methods of an active distribution network with which the reduced model can be automatically established according to a given threshold of reduction error.The combined state-space nodal analysis framework is employed to apply the automated model reduction algorithm in popular EMTP-type simulation programs.Simulations are performed using PSCAD and a self-developed program to show the feasibility and validity of the proposed methods.