Evaluating the reliability of distributed photovoltaic energy system and storage against household blackout

Distributed energy resources have been proven to be an effective and promising solution to enhance power system resilience and improve household-level reliability.In this paper,we propose a method to evaluate the reliability value of a photovoltaic(PV)energy system with a battery storage system(BSS)by considering the probability of grid outages causing household blackouts.Considering this reliability value,which is the economic profit and capital cost of PV+BSS,a simple formula is derived to calculate the optimal planning strategy.This strategy can provide household-level customers with a simple and straightforward expression for invested PV+BSS capacity.Case studies on 600 households located in eight zones of the US for the period of 2006 to 2015 demonstrate that adding the reliability value to economic profit allows households to invest in a larger PV+BSS and avoid loss of load caused by blackouts.Owing to the differences in blackout hours,households from the 8 zones express distinct willingness to install PV+BSS.The greater the probability of blackout,the greater revenue that household can get from the PV+BSS.The simulation example shows that the planning strategy obtained by proposed model has good economy in the actual operation and able to reduce the economic risk of power failure of the household users.This model can provide household with an easy and straightforward investment strategy of PV+BSS capacity.

A review on current conventional and biotechnical approaches to enhance biosynthesis of steviol glycosides in Stevia rebaudiana

Stevia rebaudiana Bertoni is commonly called stevia and mostly found in the north east regions of South America.It is an herbaceous and shrubby plant belonging to the Asteraceae family.Stevia is considered as a natural sweetener and a commercially important plant worldwide.The leaves of S.rebaudiana contain steviol glycosides(SGs)which are highly potent and non-caloric sweeteners.The sweetening property of S.rebaudiana is contributed to the presence of these high potency,calorie free steviol glycosides.SGs are considerably suitable for replacing sucrose and other artificial sweetening agents which are used in different industries and pharmaceuticals.SGs amount in the plant mostly varies from 8%to 10%,and the enhancement of SGs is always in demand.These glycosides have the potential to become healthier alternatives to other table sugars for having desirable taste and zero calories.SGs are almost 300 times sweeter than sucrose.Being used as alternative sugar intensifier the commercial value of this plant in biopharmaceutical,food and beverages industries and in international market is increasing day by day.SGs have made stevia an important part of the medicinal world as well as the food and beverage industry,but the limited production of plant material is not fulfilling the higher global market demand.Therefore,researchers are working worldwide to increase the production of important SGs through the intercession of different biotechnological approaches in S.rebaudiana.This review aims to describe the emerging biotechnological strategies and approaches to understand,stimulate and enhance biosynthesis of secondary metabolites in stevia.Conventional and biotechnological methods for the production of steviol glycosides have been briefly reviewed and discussed.

A Novel Named Entity Recognition Scheme for Steel E-Commerce Platforms Using a Lite BERT

In the era of big data,E-commerce plays an increasingly important role,and steel E-commerce certainly occupies a positive position.However,it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs.In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms,we propose a novel deep learning-based loss function for named entity recognition(NER).Considering the impacts of small sample and imbalanced data,in our NER scheme,the focal loss,the label smoothing,and the cross entropy are incorporated into a lite bidirectional encoder representations from transformers(BERT)model to avoid the over-fitting.Moreover,through the analysis of different classic annotation techniques used to tag data,an ideal one is chosen for the training model in our proposed scheme.Experiments are conducted on Chinese steel E-commerce datasets.The experimental results show that the training time of a lite BERT(ALBERT)-based method is much shorter than that of BERT-based models,while achieving the similar computational performance in terms of metrics precision,recall,and F1 with BERT-based models.Meanwhile,our proposed approach performs much better than that of combining Word2Vec,bidirectional long short-term memory(Bi-LSTM),and conditional random field(CRF)models,in consideration of training time and F1.

Clinical observation of Shenling Baizhu Powder combined with triamcinolone acetonide in treating macular edema induced by retinal vein occlusion

Objective:to observe the clinical effica-cy of Shenling Baizhu Powder(SLBZP)combined with a subconjunctival injection of triamcinolone acetonide(TA)in treating macular edema(ME)induced by retinal vein occlusion(RVO).Method:there were 62 patients(62 eyes)with ME induced by RVO that were selected and divided into two groups in accordance with the ran-dom number table.Each group had 31 eyes.Group one,the control group,was treated with a single subconjunc-tival injection of TA;group two,the observation group,was treated with a single subconjunctival injection of TA(20 mg/0.5 mL)per eye and one month of SLBZP.To evaluate the clinical efficacy,both groups were checked(3×)with the best corrected-visual acuity(BCVA),cen-ter macular thickness(CMT),and intraocular pressure(IOP).The checks were before treatment,one month af-ter injection,and three months after injection.Results:there were 26 eyes(83.87%)in the observation group,and 17 eyes(54.84%)in the control group in which the BCVA was significantly improved.The ME obviously de-creased in 27 eyes(87.10%)the observation group and in 19 eyes(61.29%)the control group.The clinical effica-cy of the observation group was significantly better than that of the control group(P<0.05).Conclusion:as one method to treat ME induced by RVO,SLBZP combined with subconjunctival injection of TA is significantly more effective than a single subconjunctival injection of TA.Besides,the SLBZP had less side-effects.Based on the above,this method deserves in-depth research.

Cyber-physical Collaborative Restoration Strategy for Power Transmission System Considering Maintenance Scheduling

In order to improve the ability of power transmission system to cope with compound faults on the communication side and power side,a cyber-physical collaborative restoration strategy is proposed.First,according to the information system’s role in fault diagnosis,remote control of equipment maintenance and automatic output adjustment of generator restoration,a cyber-physical coupling model is proposed.On this basis,a collaborative restoration model of power transmission system is established by studying interactions among maintenance schedule paths,information system operation,and power system operation.Based on power flow linearization and the large M-ε method,the above model is transformed into a mixed integer linear programming model,whose computational burden is reduced further by the clustering algorithm.According to the parameters of IEEE39 New England system,the geographic wiring diagram of the cyber-physical system is established.Simulation results show the proposed restoration strategy can consider the support function of the information system and space-time coordination of equipment maintenance at both sides comprehensively to speed up load recovery progress.

Research progress in performance improvement strategies and sulfur conversion mechanisms of Li-S batteries based on Fe series nanomaterials

Lithium-sulfur(Li-S)batteries hold the potential to revolutionize energy storage due to the high theoretical capacity and energy density.However,the commercialization process is seriously hindered by the rapid capacity decay and low utilization of sulfur,caused by the inevitable slow dynamics and the“shuttle effect”.The incorporation of metal-based electrocatalysts into sulfur cathodes shows promise in promoting the conversion of lithium polysulfides(LiPSs),reducing the“shuttle effect”,and enhancing cell kinetics and cycle life.Among these,Fe-based materials,characterized by environmental friendliness,low cost,abundant reserves,and high activity,are extensively used in sulfur cathode modification.This article reviews the advancements of Fe-based materials in enhancing Li-S batteries in recent years.Starting from single/multi-component Fe-based metal compounds and single/bimetallic atoms,the influence of different Fe coordination environments on the conversion mechanism of LiPSs is analyzed.It is hoped that this review and the proposed prospects can further stimulate the development and application of the Fe element in Li-S batteries in the future.

摩擦力显微镜表征二维材料晶格结构研究

摩擦力显微镜(friction force microscopy,FFM)是一种基于摩擦力信号的原子力显微镜,能够对二维材料晶格进行快速、无损的高分辨成像.然而,由于热漂移、黏附力、表面静电等因素的影响,环境条件下二维材料的高分辨FFM成像仍面临着巨大挑战.基于以上问题,本文以高定向热解石墨为标准样品,通过对探针在样品表面黏滑行为的分析,系统研究了探针弹性常数、正应力和扫描速度对高分辨FFM成像的影响,并建立了一套可靠的二维材料晶格结构表征方法.该方法能够获得精确的结构信息,所测得的二维材料晶格常数平均误差小于2.3%.此外,该方法还适用于化学气相沉积法和剥离法制备的多种二维材料,展现出较高的普适性.本文的研究结果为环境条件下二维材料晶格结构的精确表征提供了新思路.

Current advances in design and engineering strategies of industrial enzymes

Enzymes are considered as functional proteins,also known as biocatalysts,which are required for normal cellular function.The commercial production of enzymes with distinct features always remains the top priority of researchers for industrial biocatalysis.However,the insufficient yield,low stability,low activity,formation of by-products,complex purification pro-cess,and many other factors are challenging for the enzyme production industry.Novel advancements in protein engineering,especially the combination of multidisciplinary techniques including post-translational enzyme modification,structured assisted protein tailoring and computational modeling approaches,open a new horizon to more efficient production of bio-catalysts.In this review,we focus on the development process of enzyme modification design strategies,such as rational design,semi-rational design and de novo design.Selected examples for each strategy,which are particularly useful for novel enzyme design,are given.We hope this review is helpful for the development of biocatalysts for industrial application.

Deep ultraviolet hydrogel based on 2D cobalt-doped titanate

Birefringent optical elements that work in deep ultraviolet(DUV)region become increasingly important these years.However,most of the DUV optical elements have fixed birefringence which is hard to be tuned.Here,we invent a birefringence-tunable optical hydrogel with mechano-birefringence effect in the DUV region,based on two-dimensional(2D)low-cobalt-doped titanate.This 2D oxide material has an optical anisotropy factor of 1.5×10^(-11) C^(2)J^(-1) m-1,larger than maximum value obtained previously,leading to an extremely large specific magneto-optical Cotton-Mouton coefficient of 3.9×10^(6) T^(-2) m-1.The extremely large coefficient enables the fabrication of birefringent hydrogel in a small magnetic field with an ultra-low concentration of 2D oxide material.The hydrogel can stably and continuously modulate 303 nm DUV light with large phase tunability by varying the strain(compression or stretching)from 0 to 50%.Our work opens the door to design and fabricate new proof-of-concept DUV birefringence-tunable element,as demonstrated by optical hydrogels capable of DUV modulation by mechanical stimuli.

Strong size effect on deformation twin-me diate d plasticity in body-centered-cubic iron

Deformation twinning serves as an important mode of plastic dissipation processes in nanoscale body-centered cubic(BCC)metals,but its origin and spatio-temporal features are mysterious.Here,applying in situ tensile experiments,we report a strong size effect on mediating the twinning behaviors and twin boundary(TB)-dislocation interaction mechanisms in BCC iron(Fe)nanowires(NWs).There exists a critical diameter(d)of∼2.5 nm,above which the deformation twinning rather than dislocation slip dominates the plasticity.Unlike the traditional reflection TBs,the intermediate isosceles TBs are consis-tently observed as mediated by the 1/12<111>partial dislocations.Moreover,we uncover two distinct TB-related deformation mechanisms,including twin variant re-orientation and TB cracking for NWs with d<17 nm and d>17 nm,respectively.Further molecular dynamics and statics simulations provide the basic underlying mechanisms for size-dependent plasticity,which have been largely overlooked in previous experimental investigations.Our findings highlight the importance of grain size in mediating the deformation behaviors in Fe,serving as possible guidance for exploring single-crystalline and poly-crystalline Fe-based materials(e.g.steel)with optimized mechanical performance.

Traditional Chinese medicine for age-related macular degeneration: A clinical evidence map between 2000 and 2022

Background:We systematically searched and summarized clinical studies on traditional Chinese medicine(TCM)for age-relatedmacular degeneration(AMD)with the method of evidence map.We aimed to provide evidence and research direction for the prevention or treatment of AMD with TCM in the future.Materials and methods:We searched PubMed,Web of Science,EMBASE,and Chinese databases including CNKI(Chinese National Knowledge Infrastructure),WanFang and VIP,ClinicalTrials.gov,and ChineseClinical Trial Registry Center studies on the prevention or treatment of TCMfor AMD from January 2000 to November 2022.We showed distribution features of these studies in the form of text description,graphs,and tables.Results:The final 258 articles included 245 clinical studies,9 systematic reviews ormeta-analyses,and 4 guidelines,expert consensus,or clinical pathway.After analyzing the articles with a focus on the stage of AMD,study type,sample size,intervention measures,outcome indicators,and the quality of evidence,we found that the studies were increasing,most of which were wet AMD,the main study type was randomized controlled trials,and the sample size was mostly fewer than 100 cases.Different interventions of TCM,such as Chinese medicine,Chinese patentmedicine,or acupuncture,showed the potential benefits of improving vision,reducing fundus lesions,and alleviating some uncomfortable symptoms.However,the sample size of these studies was small.The outcome indicators were not unified,and the stage of AMD was unclear.The quality of articles was lower,and there were few studies on early AMD.The advantages of TCM for the prevention or treatment of AMD remained unclear.Conclusions:Early intervention will be the focus and direction of AMD in the prevention or treatment of TCM,and more standardized clinical studies of TCM for early AMD need to be designed and carried out in the future.

Chitin deacetylase:from molecular structure to practical applications

Chitosan and chitooligosaccharides(COS),as derivatives of chitin through deacetylation reaction,have broad applications due to their good biodegradability,biocompatibility,and solubility.In addition,chitosan and COS are involved in cell wall morphogenesis and host–pathogen interactions in vivo.Chitin deacetylases(CDAs)are enzymes that can catalyze the deN-acetylation of chitin.They are widely distributed in protozoa,algae,bacteria,fungi,and insects with important physiological functions.Compared with the traditional chemical method,enzymatic catalysis by CDAs provides an enzymatic catalysis method to produce chitosan and COS with controllable deacetylation site and environmental friendliness.These characteristics attract researchers to produce CDAs by fungicides or pesticides.However,researches on heterologous expression and directed evolution of CDAs are still lacking.In this review,we summarize the latest knowledge of CDAs,especially for heterologous expression systems and directed evolution strategies,which may contribute to the industrial production and future application of CDAs.