Step‑by‑Step Modulation of Crystalline Features and Exciton Kinetics for 19.2%Efficiency Ortho‑Xylene Processed Organic Solar Cells

With plenty of popular and effective ternary organic solar cells(OSCs)construction strategies proposed and applied,its power conversion efficiencies(PCEs)have come to a new level of over 19%in single-junction devices.However,previous studies are heavily based in chloroform(CF)leaving behind substantial knowledge deficiencies in understanding the influence of solvent choice when introducing a third component.Herein,we present a case where a newly designed asymmetric small molecular acceptor using fluoro-methoxylated end-group modification strategy,named BTP-BO-3FO with enlarged bandgap,brings different morphological evolution and performance improvement effect on host system PM6:BTP-eC9,processed by CF and ortho-xylene(o-XY).With detailed analyses supported by a series of experiments,the best PCE of 19.24%for green solvent-processed OSCs is found to be a fruit of finely tuned crystalline ordering and general aggregation motif,which furthermore nourishes a favorable charge generation and recombination behavior.Likewise,over 19%PCE can be achieved by replacing spin-coating with blade coating for active layer deposition.This work focuses on understanding the commonly met yet frequently ignored issues when building ternary blends to demonstrate cutting-edge device performance,hence,will be instructive to other ternary OSC works in the future.

Calculation of the Gas Injection Rate and Pipe String Erosion in Nitrogen Drilling Systems

Detailed information is provided for the design and construction of nitrogen drilling in a coal seam.Two prototype wells are considered.The Guo model is used to calculate the required minimum gas injection rate,while the Finnie,Sommerfeld,and Tulsa models are exploited to estimate the ensuing erosion occurring in pipe strings.The calculated minimum gas injection rates are 67.4 m^(3)/min(with water)and 49.4 m^(3)/min(without water),and the actual field of use is 90–120 m^(3)/min.The difference between the calculated injection pressure and the field value is 6.5%–15.2%(formation with water)and 0.65%–7.32%(formation without water).The results show that the Guo model can more precisely represent the situation of the no water formation in the nitrogen drilling of a coal seam.The Finnie,Sommerfeld,and Tulsa models have different sensitivities to cutting densities,particle size,impact velocity and angle,and pipe string hardness.

Topological Order Value Iteration Algorithm for Solving Probabilistic Planning

AI researchers typically formulated probabilistic planning under uncertainty problems using Markov Decision Processes (MDPs).Value Iteration is an inef?cient algorithm for MDPs, because it puts the majority of its effort into backing up the entire state space, which turns out to be unnecessary in many cases. In order to overcome this problem, many approaches have been proposed. Among them, LAO*, LRTDP and HDP are state-of-the-art ones. All of these use reach ability analysis and heuristics to avoid some unnecessary backups. However, none of these approaches fully exploit the graphical features of the MDPs or use these features to yield the best backup sequence of the state space. We introduce an improved algorithm named Topological Order Value Iteration (TOVI) that can circumvent the problem of unnecessary backups by detecting the structure of MDPs and backing up states based on topological sequences. The experimental results demonstrate the effectiveness and excellent performance of our algorithm.

Green‑Solvent Processed Blade‑Coating Organic Solar Cells with an Efficiency Approaching 19%Enabled by Alkyl‑Tailored Acceptors

Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.

生物天敌暴发导致珊瑚礁退化的高分遥感监测与分析——以南海太平岛为例

珊瑚生物天敌黑皮海绵、长棘海星在世界范围内暴发严重威胁珊瑚礁生态健康,然而目前珊瑚礁领域尚缺乏生物天敌暴发后对珊瑚礁地貌类型影响的定量研究。文章利用太平岛珊瑚生物天敌黑皮海绵、长棘海星2次暴发事件前后,覆盖太平岛2016—2022年的26期Sentinel-2遥感影像,结合高分辨率GF-2(PMS)遥感影像和卫星遥感影像地理信息系统Google Earth平台中的数据,开展中国南海太平岛珊瑚礁地貌类型遥感影像分类实验,对密集珊瑚沉积区、稀疏珊瑚沉积区、珊瑚丛生区、沙坪、浅礁前斜坡等珊瑚礁地貌类型演变进行特征分析。结果表明:1)结合专家解译知识和支持向量机(Support Vector Machine,SVM)分类算法开展的太平岛珊瑚礁地貌类型分类,最高总体精度和Kappa系数分别为96.46%和0.94。2)在2种珊瑚生物天敌暴发期间,太平岛的珊瑚礁丛生区、密集珊瑚沉积区、稀疏珊瑚沉积区等珊瑚礁地貌类型面积有显著下降;黑皮海绵暴发后对密集珊瑚沉积区影响最大,其面积减少72.92%;长棘海星暴发后对珊瑚丛生区影响最大,其面积减少59.17%。3)2016—2022年,太平岛珊瑚礁退化率高于恢复率,其中2017年3—6月珊瑚礁退化率最高,为23.88%;在2017年6—9月珊瑚礁恢复率最高,为18.03%。

Orbital pacing and secular evolution of lake-level changes reconstructed by sedimentary noise modeling during the Early Jurassic icehouses-(super)greenhouses

Lake-level changes can significantly affect paleoenvironmental evolution,resource occurrence,terrestrial carbon budget,and biodiversity in continental basins.Climate is one of the most critical factors controlling lake-level changes.Paleoclimate of the Early Jurassic has been evidenced by oscillating icehouses to(super)greenhouses with interrupted intermittent extreme climatic events(hyperthermal and cooling),e.g.,the Toarcian oceanic anoxic event(~183 Ma)and the late Pliensbachian cooling event(~185 Ma).Lake-level evolution and hydrologic cycling on Earth’s surface during the Early Jurassic icehouses-to-(super)greenhouses are thus far poorly understood due to a lack of continuous high-resolution nonmarine evidence.Here we present a super-long nonmarine lake level record for this pivotal interval from the early Pliensbachian to Toarcian by sedimentary noise modeling,and construct a 16.7-Myr-long astronomical time scale(174.2 Ma to 190.9 Ma)based on cyclostratigraphy analysis of rock color datasets(CIE b*)of the Qaidam Basin.Our results document lake-level oscillations on a 5-to 10-million-year(Myr)scale which shows a pronounced correlation with long-term climate variation and extreme climatic events,and 1-to 2.5-Myr-scale lake-level changes that are prominently paced by the 2.4-Myr long-eccentricity forcing and the 1.2-Myr obliquity forcing.At the Pliensbachian Stage,the 1.2-Myr-scale lake-level changes are in phase with the coeval sealevel variations.Orbitally forced growth and decay of the ephemeral or permanent ice sheets in polar regions are interpreted to control the synchronous ups-and-downs of continental lake level and global sea level.However,during the Toarcian ice-free greenhouses to(super)greenhouses,the 1.2-Myr-scale lake-level variations show an anti-phase relationship with global sea level,indicating a‘seesaw’interaction between continental reservoirs(lakes and groundwater)and global oceans.The 2.4-Myr longeccentricity cycles mainly regulate variations of lake level and sea level by controlling the growth and decay of small-scale continental ice sheets,which is especially notable during the Pliensbachian Stage.These findings indicate a remarkable transition of hydrological cycling pattern during the Pliensbachian-Toarcian icehouses to(super)greenhouses,which provides new perspectives and evidence for investigating the hypothesis of global sea-level changes(e.g.,glacio-eustasy and aquifer-eustasy)and long-period astronomical forcing in nonmarine stratigraphy.

Enhanced conductivity and stability of Prussian blue cathodes in sodium-ion batteries by surface vapor-phase molecular selfassembly

With many merits such as facile synthesis,economy,and relatively high theoretical capacity,Prussian blue analogs(PBAs)are considered promising cathode materials for sodium-ion batteries(SIBs).However,their practical applications still suffer from a low actual specific capacity and inferior stability owing to the imperfect crystallinity,irreversible phase transition,and low intrinsic conductivity.Herein,a surface-modification technique for vapor-phase molecular self-assembly was developed to prepare Fe-based PBAs,specifically sodium iron hexacyanoferrate(NaFeHCF),with a uniform conductive polymer protective layer of polypyrrole(PPy)on the surface,resulting in NaFeHCF@PPy.The incorporation of a PPy protective layer not only improves the electronic conductivity of NaFeHCF@PPy,but also effectively mitigates the dissolution of Fe-ions during cycling.Specifically,this advanced vapor-phase technique avoids Fe^(2+)oxidation and Na^(+)loss during liquid-phase surface modification.The NaFeHCF@PPy exhibited a remarkably enhanced cycling performance,with capacity retentions of 85.6%and 69.1%over 500 and 1000 cycles,respectively,at 200 mA/g,along with a superior rate performance up to 5 A/g(fast kinetics).Additionally,by adopting this strategy for Mn-based PBAs(NaMnHCF@PPy),we further demonstrated the universality of this method for PBA cathodes in SIBs.

基于灰色关联度的农业类上市公司经营评价

作为农业产业化经营的市场开拓者、组织者、带动者和技术创新主体, 农业类上市公司是实现农业产业化经营的营运中心、信息中心和服务中心,是带动整个农业产业链条运行和深化,带领广大农民面对市场、生产致富的关键。因此,其经营状况对于国民经济的发展具有非常重要的意义。为对我国农业类上市公司经营状况进行评价,本文选取了已经在国内上市的农业类公司作为研究对象,在建立农业类上市公司经营绩效综合评价指标体系的基础上,运用灰色关联度分析法,对这15家公司的经营绩效作了排序和评价分析。结果发现除星河生物、登海种业以及荃银高科以外,其他12家农业类上市公司经营绩效的灰色关联度得分差距不是很大,排名第4位的万象德农与排名第15位的亚盛集团两者经营绩效的灰色关联度得分之差仅为0.1082。

Integrating surface and interface engineering to improve optoelectronic performance and environmental stability of MXenebased heterojunction towards broadband photodetection

Two-/three-dimensional(2D/3D)heterojunction-based photodetectors have attracted much attention due to their highly efficient photoelectric conversion driven by the built-in electric field for high-speed photoresponse.However,a large dark current induced by unexpected surface states at the interface between 2D materials and 3D bulks is widely observed in such structures,greatly degrading their optoelectronic performance.Herein,a heterojunction of proton acid HCl treated MXene(H-MXene)/TiO_(2)/Si via integrating surface and interface engineering is fabricated,which exhibits decreased dark current and improved environmental stability.A feasible strategy to optimize the interface properties between MXene and Si is proposed by an in-situ oxidation process of MXene into TiO_(2),resulting in a suppressed dark current as well as high specific detectivity.Benefitting from the enhanced light absorption of MXene on the bulk Si substrate,the photoresponse of as-fabricated devices in the near-infrared region is also elevated.Moreover,the treatment of proton acid HCl on the surface of MXene brings better conductivity and environmental stability due to the decreased layer spacing of MXene,which is further confirmed by both experimental and theoretical methods.This work opens a unique way to comprehensively boost the optoelectronic performance of MXene-based photodetectors.

Emergy Analysis of the Agricultural Eco-economic System in Dongting Lake Area of Hunan Province

[ Objective] The reseamh aimed to discuss eco-efficiency of the agro-ecosystem in Dongting Lake area of Hunan. [ Method] By referring to emergy reseamh method, emergy structure, function and efficiency of the system were analyzed according to emergy input -output data of the system in 2009. [ Result] The system had developed economy, and mechanization and modernization degrees were higher. Emergy output of the system was unbalanced, and market pricing of the agricultural product was significantly lower, especially farming product. Seen from sustainable development index and environmental loading ratio of the system, the system was full of vitality and development potential. The pressure of natural resources and environment was not very great, but the system accommodated too many populations. [ Conclusion] Basic direction of the agricultur- al policy in the zone was further shortening industrial and agricultural price scissors, continuing to implement price protection of the farming product, adjusting agricultural and product structures and transferring surplus labor.

Fuzzy impedance control of an electro-hydraulic actuator with an extended disturbance observer

In this paper,we deal with both velocity control and force control of a single-rod electro-hydraulic actuator subject to external disturbances and parameter uncertainties.In some implementations,both velocity control and force control are required.Impedance control and an extended disturbance observer are combined to solve this issue.Impedance control is applied to regulate the dynamic relationship between the velocity and output force of the actuator,which can help avoid impact and keep a proper contact force on the environment or workpieces.Parameters of impedance rules are regulated by a fuzzy algorithm.An extended disturbance observer is employed to account for external disturbances and parameter uncertainties to achieve an accurate velocity tracking.A detailed model of load force dynamics is presented for the development of the extended disturbance observer.The stability of the whole system is analyzed.Experimental results demonstrate that the proposed control strategy has not only a high velocity tracking performance,but also a good force adjustment performance,and that it should be widely applied in construction and assembly.

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Two dimensional （2D） nanocrystals of noble metals （e.g., Au, Ag, Pt） often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedi- cines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals （e.g., shapes, thickness, and lateral sizes）. This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applica- tions of these nanocrystals are also discussed.

Development of an efficient expression system with large cargo capacity for interrogation of gene function in bamboo based on bamboo mosaic virus

Bamboo is one of the fastest growing plants among monocotyledonous species and is grown extensively in subtropical regions.Although bamboo has high economic value and produces much biomass quickly,gene functional research is hindered by the low efficiency of genetic transformation in this species.We therefore explored the potential of a bamboo mosaic virus(BaMV)-mediated expression system to investigate genotype-phenotype associations.We determined that the sites between the triple gene block proteins(TGBps)and the coat protein(CP)of BaMV are the most efficient insertion sites for the expression of exogenous genes in both monopodial and sympodial bamboo species.Moreover,we validated this system by individually overexpressing the two endogenous genes ACE1 and DEC1,which resulted in the promotion and suppression of intemode elongation,respectively.In particular,this system was able to drive the expression of three 2A-linked betalain biosynthesis genes(more than 4 kb in length)to produce betalain,indicating that it has high cargo capacity and may provide the prerequisite basis for the development of a DNA-free bamboo genome editing platform in the future.Since BaMV can infect multiple bamboo species,we anticipate that the system described in this study will greatly contribute to gene function research and further promote the molecular breeding of bamboo.

Regioselective Electrochemical Hydroalkylations of[60]Fullerene-Fused Furochromenone

Comprehensive Summary Regioselective electrochemical hydroalkylations of[60]fullerene-fused furochromenone with alky halides under different acidic conditions unexpectedly afford three types of tetra-functionalized[60]fullerene derivatives in high yields.When acetic acid is used as the proton source,two 1,2,3,4-adducts with retained or rearranged five-membered heterocycle are obtained as major and minor products,respectively.While trifluoroacetic acid is employed as the proton source,1,2,3,16-adducts and 1,2,3,4-adducts,both with the five-membered heterocycle rearranged from[6,6]-junction to[5,6]-junction,are generated.Intriguingly,the obtained 1,2,3,16-adducts can be transformed into 1,2,3,4-adducts accompanied by rearrangement of the fused five-membered heterocycle from[5,6]-junction to[6,6]-junction.These products have been characterized by spectroscopic data and single-crystal X-ray analysis.Moreover,the two 1,2,3,4-adducts with the heterocycle fused to[5,6]-junction or[6,6]-junction show diagnostic UV-vis spectra,which may be useful for the identification of these two types of 1,2,3,4-adducts in the future.A plausible reaction mechanism has been proposed to elucidate the formation of hydroalkylation products in the presence of different acids.

Renewable Energy Transmission by HVDC Across the Continent:System Challenges and Opportunities

Rapid development of renewable energy in China is driving a major shift in the characteristics and control requirements of the electricity grid.Since the best renewable energy resources are far away from load centers in the east and southeast,transmission over long distances is required.Over 20 high-voltage DC(HVDC)transmission lines,with a combined capacity exceeding 150 GW,are in operation or are currently under construction.This rapid expansion of new generation and transmission capacities based on power electronics starts to change the characteristics of the grid,especially in areas where they concentrate,creating new stability problems and operational challenges.New system theories and technologies are required to support the development and operation of a future grid that relies more and more on power electronics.This paper highlights the characteristics of power electronics as used in renewable energy generation and HVDC transmission systems,discusses the impacts of these power-electronics-based assets on grid stability and operational requirements,and identifies opportunities for the development of both new system theories and system technologies to support a national energy policy that emphasizes the use of clean energy.

Benefit Evaluation of the Deep Peak-regulation Market in the Northeast China Grid

In the Northeast China Grid(NCG),the percentage of wind power has reached nearly 20%of the total installed generation capacity,which causes increasing demands for deep peak-regulation capacity(DPC)during the operation of power systems.The shortage of DPC has become a significant problem in the NCG which may lead to wind curtailments and affect the security of power systems as well as the heating needs for inhabitants.In order to cope with this DPC shortage issue,the deep peak-regulation market(DPM)was established and has been running steadily in the past few years in NCG.This paper elaborates on the roles of the market players and the operational processes of the DPM,of which the advancements in terms of management mechanism are summarized.Moreover,benefits of the DPM for social harmony,environmental protection and economic efficiency are analyzed,for which relevant evaluation indices are proposed.A five-unit simulation system is constructed to illustrate the operation and benefits of the DPM.And focusing on comparisons with the previous Two Rules,the case study of Liaoning Power Grid verifies further that the DPM is feasible and able to bring more benefits to grids.

Programmable van-der-Waals heterostructure-enabled optoelectronic synaptic floating-gate transistors with ultra-low energy consumption

Van der Waals(vdW)heterostructures provide a unique opportunity to develop various electronic and optoelectronic devices with specific functions by designing novel device structures,especially for bioinspired neuromorphic optoelectronic devices,which require the integration of nonvolatile memory and excellent optical responses.Here,we demonstrate a programmable optoelectronic synaptic floating-gate transistor based on multilayer graphene/h-BN/MoS2 vdW heterostructures,where both plasticity emulation and modulation were successfully realized in a single device.The dynamic tunneling process of photogenerated carriers through the as-fabricated vdW heterostructures contributed to a large memory ratio(105)between program and erase states.Our device can work as a functional or silent synapse by applying a program/erase voltage spike as a modulatory signal to determine the response to light stimulation,leading to a programmable operation in optoelectronic synaptic transistors.Moreover,an ultra-low energy consumption per light spike event(~2.5 fJ)was obtained in the program state owing to a suppressed noise current by program operation in our floating-gate transistor.This study proposes a feasible strategy to improve the functions of optoelectronic synaptic devices with ultra-low energy consumption based on vdW heterostructures designed for highly efficient artificial neural networks.

Optimal Decomposition of Stochastic Dispatch Schedule for Renewable Energy Cluster

The correlated renewable energy farms are usually aggregated as a cluster in economic dispatch to relieve computational burden.This strategy can also achieve better performance since the precision of predicting the power generation of a cluster can be higher than those of individual farms.This paper proposes an optimal decomposition method to allocate dispatch schedules among renewable energy farms(REFs)in the cluster under existing stochastic optimization framework.The proposed model takes advantage of probabilistic characteristics of renewable generation to minimize the curtailment and ensure the feasibility of dispatch schedule of the clusters.Approximated tractable formulation and efficient solution method are the proposed to solve the proposed model.Numerical tests show that the proposed method achieves the optimal decomposition of dispatch schedule among REFs and facilitates the utilization of renewable generation.

Multi-temporal remote sensing of land cover change and urban sprawl in the coastal city of Yantai, China

The importance of accurately mapping and monitoring land cover changes over time is increasing,especially in rapidly growing coastal cities.In this study,three pairs of Landsat images of Yantai,a representative coastal city in China,from 1989,1999,and 2009 were selected to monitor land cover changes and urban sprawl dynamics.To improve the classification accuracy,three classification methods together with the minimum noise fraction(MNF)and pixel purity index(PPI)calculations were performed on the images.The classification results showed that the overall five-class classification accuracies averaged 91.38%for the 20-year period,which produced an accuracy of 83.78%for change maps.The analysis of change maps indicated that from 1989 to 2009,the percentage of urban area increased from 31.41%to 50.28%of the total area,and the newly urbanized area was mainly located in residential areas and the reclaimed harbor region.Analysis of the relationships between urban area and its driving forces obtained from statistical data found that the urban sprawl of Yantai before 2000 was relatively extensive,which is consistent with the conclusion drawn by using remote sensing techniques.The research results could be used as inputs for sustainable urban management and establishing Digital Earth database.

The inheritance and innovation of ancient book collation paradigm in the digital environment

Collating ancient books has a long history in China and has formed a kind of relatively stable pattern.In Han Dynasty,a famous philologist named Liu Xiang created a general procedure and a set of methods to collate Chinese ancient books,which included collecting various editions of the same book,choosing an appropriate title for the book,reordering papers,correcting words,making a fair copy of the final version,cataloging and classifying books.This procedure and the set