Flexibility potential of Cs_(2)BX_(6)(B=Hf,Sn,Pt,Zr,Ti;X=I,Br,Cl)with application in photovoltaic devices and radiation detectors

As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.

A Path Planning Algorithm Based on Improved RRT Sampling Region

For the problem of slow search and tortuous paths in the Rapidly Exploring Random Tree(RRT)algorithm,a feedback-biased sampling RRT,called FS-RRT,is proposedbasedon RRT.Firstly,toimprove the samplingefficiency of RRT to shorten the search time,the search area of the randomtree is restricted to improve the sampling efficiency.Secondly,to obtain better information about obstacles to shorten the path length,a feedback-biased sampling strategy is used instead of the traditional random sampling,the collision of the expanding node with an obstacle generates feedback information so that the next expanding node avoids expanding within a specific angle range.Thirdly,this paper proposes using the inverse optimization strategy to remove redundancy points from the initial path,making the path shorter and more accurate.Finally,to satisfy the smooth operation of the robot in practice,auxiliary points are used to optimize the cubic Bezier curve to avoid path-crossing obstacles when using the Bezier curve optimization.The experimental results demonstrate that,compared to the traditional RRT algorithm,the proposed FS-RRT algorithm performs favorably against mainstream algorithms regarding running time,number of search iterations,and path length.Moreover,the improved algorithm also performs well in a narrow obstacle environment,and its effectiveness is further confirmed by experimental verification.

Novel thick-target inverse kinematics method for the astrophysical ^(12)C+^(12)C fusion reaction

The ^(12)C+^(12)C fusion is one of the most important reactions in modern nuclear astrophysics.The trend and magnitude of the reaction rate within the Gamow window strongly influence various astrophysical processes.However,direct measurement of this reaction is extremely difficult,which makes it necessary to develop indirect methods.In this study,the ^(23)Na+p reaction system was used to study the compound nucleus ^(24)Mg.We employed a thick-target inverse kinematics method combined with the-charged-particle coincidence technique to measure the proton andexit channels of ^(24)Mg.Technical details of the ^(23)Na+p thick-target inverse kinematics experiment and analysis are presented herein.

A Novel Scheme for Separate Training of Deep Learning-Based CSI Feedback Autoencoders

In this paper, we introduce a novel scheme for the separate training of deep learning-based autoencoders used for Channel State Information (CSI) feedback. Our distinct training approach caters to multiple users and base stations, enabling independent and individualized local training. This ensures the more secure processing of data and algorithms, different from the commonly adopted joint training method. To maintain comparable performance with joint training, we present two distinct training methods: separate training decoder and separate training encoder. It’s noteworthy that conducting separate training for the encoder can pose additional challenges, due to its responsibility in acquiring a compressed representation of underlying data features. This complexity makes accommodating multiple pre-trained decoders for just one encoder a demanding task. To overcome this, we design an adaptation layer architecture that effectively minimizes performance losses. Moreover, the flexible training strategy empowers users and base stations to seamlessly incorporate distinct encoder and decoder structures into the system, significantly amplifying the system’s scalability. .

The telomere-to-telomere genome of Fragaria vesca reveals the genomic evolution of Fragaria and the origin of cultivated octoploid strawberry

Fragaria vesca,commonly known as wild or woodland strawberry,is the most widely distributed diploid Fragaria species and is native to Europe and Asia.Because of its small plant size,low heterozygosity,and relative ease of genetic transformation,F.vesca has been a model plant for fruit research since the publication of its Illumina-based genome in 2011.However,its genomic contribution to octoploid cultivated strawberry remains a long-standing question.Here,we de novo assembled and annotated a telomere-to-telomere,gap-free genome of F.vesca‘Hawaii 4’,with all seven chromosomes assembled into single contigs,providing the highest completeness and assembly quality to date.The gap-free genome is 220785082 bp in length and encodes 36173 protein-coding gene models,including 1153 newly annotated genes.All 14 telomeres and seven centromeres were annotated within the seven chromosomes.Among the three previously recognized wild diploid strawberry ancestors,F.vesca,F.iinumae,and F.viridis,phylogenomic analysis showed that F.vesca and F.viridis are the ancestors of the cultivated octoploid strawberry F.×ananassa,and F.vesca is its closest relative.Three subgenomes of F.×ananassa belong to the F.vesca group,and one is sister to F.viridis.We anticipate that this high-quality,telomere-to-telomere,gap-free F.vesca genome,combined with our phylogenomic inference of the origin of cultivated strawberry,will provide insight into the genomic evolution of Fragaria and facilitate strawberry genetics and molecular breeding.

A Golden Decade of Polar Codes:From Basic Principle to 5G Applications

After the pursuit of seventy years,the invention of polar codes indicates that we have found the first capacity-achieving coding with low complexity construction and decoding,which is the great breakthrough of the coding theory in the past two decades.In this survey,we retrospect the history of polar codes and summarize the advancement in the past ten years.First,the primary principle of channel polarization is investigated such that the basic construction,coding method and the classic successive cancellation(SC)decoding are reviewed.Second,in order to improve the performance of the finite code length,we introduce the guiding principle and conclude five design criteria for the construction,design and implementation of the polar code in the practical communication system based on the exemplar schemes in the literature.Especially,we explain the design principle behind the concatenated coding and rate matching of polar codes in 5G wireless system.Furthermore,the improved SC decoding algorithms,such as SC list(SCL)decoding and SC stack(SCS)decoding etc.,are investigated and compared.Finally,the research prospects of polar codes for the future 6G communication system are explored,including the optimization of short polar codes,coding construction in fading channels,polar coded modulation and HARQ,and the polar coded transmission,namely polar processing.Predictably,as a new coding methodology,polar codes will shine a light on communication theory and unveil a revolution in transmission technology.

胸腹腔镜食管癌根治术中不同吻合方式的对比研究

目的对比不同吻合方式在食管癌微创治疗中的疗效。方法选择我院行微创食管癌根治术(MIE)的患者115例,依照吻合方式将患者分为端端吻合组(n=68)与端侧吻合组(n=47)。端端吻合组行端端分层吻合,端侧吻合组行端侧分层吻合。观察2组手术时间、吻合时间、术中出血量及术后住院时间等围术期指标。比较2组术后3个月并发症发生情况及生活质量。结果端端吻合组吻合时间、术后住院时间均短于端侧吻合组(P<0.05);2组手术时间、术中出血量比较差异无统计学意义(P>0.05)。术后3个月,端端吻合组吻合口瘘、胃食管反流及吻合口狭窄的发生率均低于端侧吻合组(P<0.05),2组肺部并发症发生率比较差异无统计学意义(P>0.05);端端吻合组生活质量各维度评分均高于端侧吻合组(P<0.05)。结论与端侧分层吻合相比,端端分层吻合应用于MIE,可有效减少患者手术创伤,降低术后并发症发生率,促进患者康复,提高其生活质量。

Anomalous Hall effect in ferromagnetic LaCo_(2)As_(2) and ferrimagnetic NdCo_(2)As_(2)

We conducted a comparative study of the magnetic and transport properties of single-crystalline LaCo_(2)As_(2) and NdCo_(2)As_(2).LaCo_(2)As_(2) is a soft metallic ferromagnet which exhibits purely intrinsic anomalous Hall effect(AHE) due to Co-3d electrons. With Nd-4f electronic magnetism, ferrimagnetic NdCo_(2)As_(2) manifests pronounced sign reversal and multiple hysteresis loops in temperature-and field-dependent magnetization, Hall resistivity, and magnetoresistance, due to complicated magnetic structural changes. We reveal that the AHE for NdCo_(2)As_(2) is stemming from the Co sub-lattice and deduce its phase diagram which includes magnetic compensation and two meta-magnetic phase transitions. The sensitivity of the Hall effect on the details of the magnetic structures in ferrimagnetic NdCo_(2)As_(2) provides a unique opportunity to explore the magnetic interaction between 4f and 3d electrons and its impact on the electronic structure.

Arbitrary Decode-Forward Relaying with Re-Encoded Bits Selection Strategy for Polar Codes

In this paper,we propose an arbitrary decode-forward single-relay scheme for finite blocklength polar codes,which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver components.The relay node decodes the received message.The relay node selectively re-encodes the message and transmits it to the destination node.Furthermore,in order to minimize the upper-bound of the block error probability,we propose a selection strategy to decide the proper re-encoded bit set by the relay.Simulation results are presented to illustrate the improvement in decoding performance of the proposed scheme compared to conventional relay schemes in both additive white Gaussian noise(AWGN)channel and Rayleigh fading channel(RFC).

An Intelligent Detection Method for Optical Remote Sensing Images Based on Improved YOLOv7

To address the issue of imbalanced detection performance and detection speed in current mainstream object detection algorithms for optical remote sensing images,this paper proposes a multi-scale object detection model for remote sensing images on complex backgrounds,called DI-YOLO,based on You Only Look Once v7-tiny(YOLOv7-tiny).Firstly,to enhance the model’s ability to capture irregular-shaped objects and deformation features,as well as to extract high-level semantic information,deformable convolutions are used to replace standard convolutions in the original model.Secondly,a Content Coordination Attention Feature Pyramid Network(CCA-FPN)structure is designed to replace the Neck part of the original model,which can further perceive relationships between different pixels,reduce feature loss in remote sensing images,and improve the overall model’s ability to detect multi-scale objects.Thirdly,an Implicitly Efficient Decoupled Head(IEDH)is proposed to increase the model’s flexibility,making it more adaptable to complex detection tasks in various scenarios.Finally,the Smoothed Intersection over Union(SIoU)loss function replaces the Complete Intersection over Union(CIoU)loss function in the original model,resulting in more accurate prediction of bounding boxes and continuous model optimization.Experimental results on the High-Resolution Remote Sensing Detection(HRRSD)dataset demonstrate that the proposed DI-YOLO model outperforms mainstream target detection algorithms in terms of mean Average Precision(mAP)for optical remote sensing image detection.Furthermore,it achieves Frames Per Second(FPS)of 138.9,meeting fast and accurate detection requirements.

Critical behavior in the itinerant ferromagnet SmMn_(2)Ge_(2)

Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple magnetic phases.The critical behavior of the ferromagnetic phase transition is investigated by employing the modified Arrott plot with the Kouvel-Fisher method.The critical temperature TCis determined to be around 342.7 K with critical exponents ofβ=0.417 andγ=1.122,and the interaction function is found to be J(r)~r^(-4.68),suggesting the coexistence of long-range and shortrange magnetic interactions.Our results contribute to the understanding of complex magnetism in Sm Mn_(2)Ge_(2),which may provide fundamental guidance in future spintronic applications.

Periodical polarization reversal modulation in multiferroic MnWO_(4) under high magnetic fields

We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields in low magnetic fields(<14 T)at 4.2 K,whereas polarization reversal is directly achieved by two opposite electric fields under high magnetic fields(<45 T).Interestingly,the polarization curve of rising and falling fields for H∥u(magnetic easy axis)is irreversible when the magnetic field is close to 52 T.In this case,the rising and falling polarization curves can be individually reversed by the electric field,and thus require five cycles to recover to the initial condition by the order of the applied electric fields(+E,-E,-E,+E,+E).In addition,we find that ferroelectric phaseⅣcan be tuned from parallel to antiparallel in relation to ferroelectric phase AF2 by applying a magnetic field approximated to the c axis.

微创治疗连枷胸的手术时机选择及术后发生并发症的危险因素分析

目的 研究胸腔镜治疗连枷胸的最佳手术时机,分析术后发生肺部并发症的危险因素。方法 回顾性分析2016年1月—2021年6月中国人民解放军联勤保障部队第九四〇医院心胸外科行胸腔镜治疗连枷胸患者57例,男性36例,女性21例;年龄35~67岁,平均48.1岁;道路交通伤36例,高处坠落伤18例,其他3例。按照手术时间不同分为早期组(31例)和延期组(26例)。早期组于伤后<72h行胸腔镜治疗,延期组于伤后≥72h行胸腔镜治疗。观察两组患者术中出血量、手术时间、脱机时间、下床时间及术后住院时间等围术期指标,术后肺部并发症发生情况。分析影响术后发生肺部并发症的危险因素。结果 早期组与延期组术中出血量比较[(125.41±15.06)mL vs(130.41±15.23)mL]差异无统计学意义(P>0.05);早期组手术时间(161.18±16.17)min、脱机时间(26.44±0.98)h、下床时间(2.6±0.2)d、术后住院时间(11.6±1.4)d均少于延期组(189.16±25.05)min、(41.96±1.42)h、(3.1±0.2)d、(13.9±1.5)d,P均<0.05]。早期组肺部感染12.9%(4/31)、低氧血症3.2%(1/31)、肺不张6.52%(2/31)、气胸3.2%(1/31)及并发症发生率25.8%(8/31)均低于延期组30.8%(8/26)、7.7%(2/26)、11.5%(3/26)、7.7%(2/26)及57.7%(15/26),差异有统计学意义(P<0.05)。经对症处理,早期组及延期组发生并发症的患者均获得良好预后。经多因素Logistic回归分析,年龄≥60岁(OR:2.0463,95%CI:1.4219~5.0927)、伤后至手术时间≥72h(OR:1.8720,95%CI:1.3315~4.8803)、肋骨骨折数目>5根(OR:1.5994,95%CI:1.0926~3.8629)、手术时间>180min(OR:1.5710,95%CI:1.3360~4.2971)、脱机时间>48h(OR:2.3129,95%CI:1.0143~3.6620)为导致术后发生肺部并发症的独立危险因素(P<0.05)。结论 伤后早期行胸腔镜治疗可促进连枷胸患者术后康复,减少肺部并发症。经多因素Logistic回归分析,年龄、伤后至手术时间、肋骨骨折数目、手术时间、脱机时间是导致术后发生肺部并发症的独立危险因素。

激光汽化术与前列腺电切术治疗良性前列腺增生疗效的Meta分析

目的系统评价经尿道980nm激光汽化术与前列腺电切术(TURP)治疗良性前列腺增生(BPH)的疗效。方法收集国内外关于经尿道980nm激光汽化术与TURP治疗BPH的文献,采用Revman5.3软件进行Meta分析。结果筛选后共6篇文献符合纳入标准,总计839例,其中包括980nm激光治疗组450例和TURP组389例。Meta结果显示:和TURP组相比,980nm激光组手术时间差异无统计学意义[标准化均数差(SMD)=0.11,95%CI(-0.52,0.74),P>0.05],住院时间较短[SMD=-1.95,95%CI(-3.42,-0.48),P<0.05]及术后尿管留置时间较短[SMD=-2.64,95%CI(-3.92,-1.36),P<0.05]。980 nm激光组和TURP组在术后国际前列腺症状评分(IPSS)差异无统计学意义[加权均数差(WMD)=0.12,95%CI(-0.27,0.51),P>0.05],术后生活质量评分(QOL)评分差异无统计学意义[SMD=0.00,95%CI(-0.57,0.57),P>0.05],术后最大尿流率(Qmax)差异无统计学意义[SMD=0.06,95%CI(-0.26,0.37),P>0.05]。结论 980nm激光治疗良性BPH与经典的TURP术式相比,在住院时间和术后尿管留置时间方面有优势,远期效果无明显差异。

保留自主呼吸非插管单孔胸腔镜手术的临床应用

目的探讨保留自主呼吸非插管单孔胸腔镜治疗胸部疾病的可行性及安全性。方法回顾性分析2018-01—2018-10间应用非气管插管保留自主呼吸麻醉下单孔胸腔镜手术治疗的24例胸部疾病患者的临床资料。结果24例患者在非气管插管保留自主呼吸麻醉下应用单孔胸腔镜行手术治疗,无中转紧急插管或增加辅助切口。其中,自发性气胸20例,肺结核球1例,肺炎性假瘤2例,胸腺瘤1例。手术时间25~60min,平均35.5min。失血量10~50mL,平均20.2mL。胸腔闭式引流管引流时间1~4d,平均2.5d。术后随访5~12个月,无复发及其他并发症。结论非气管插管保留自主呼吸麻醉下单孔胸腔镜手术治疗胸部疾病,简单易行,安全可靠。

外泌体在胃癌转移中作用机制的研究进展

胃癌是发病率高且进展较快的消化道恶性肿瘤之一。随着手术、化疗、靶向治疗等多种治疗方法的不断进步,胃癌患者的5年生存率较过去有所改善,但由于胃癌早期缺乏有效的诊断方法,多数患者在确诊时往往已发生转移,预后较差。因此,对胃癌转移机制的探寻始终是胃癌研究领域的热点之一。外泌体是一种可以传递蛋白质、核酸等多种分子、实现细胞间信息交流的胞外囊泡。外泌体运载的分子参与了胃癌的转移过程,并且可能成为诊断胃癌的新型分子标志物,为胃癌的精准治疗提供了新方向。本文就外泌体在胃癌转移中的作用及机制进行综述。

User Association and Power Allocation for UAV-Assisted Networks: A Distributed Reinforcement Learning Approach

Unmanned aerial vehicles(UAVs)can be employed as aerial base stations(BSs)due to their high mobility and flexible deployment.This paper focuses on a UAV-assisted wireless network,where users can be scheduled to get access to either an aerial BS or a terrestrial BS for uplink transmission.In contrast to state-of-the-art designs focusing on the instantaneous cost of the network,this paper aims at minimizing the long-term average transmit power consumed by the users by dynamically optimizing user association and power allocation in each time slot.Such a joint user association scheduling and power allocation problem can be formulated as a Markov decision process(MDP).Unfortunately,solving such an MDP problem with the conventional relative value iteration(RVI)can suffer from the curses of dimensionality,in the presence of a large number of users.As a countermeasure,we propose a distributed RVI algorithm to reduce the dimension of the MDP problem,such that the original problem can be decoupled into multiple solvable small-scale MDP problems.Simulation results reveal that the proposed algorithm can yield lower longterm average transmit power consumption than both the conventional RVI algorithm and a baseline algorithm with myopic policies.

Joint Task Scheduling, Resource Allocation, and UAV Trajectory under Clustering for FANETs

This paper establishes a new layered flying ad hoc networks(FANETs) system of mobile edge computing(MEC) supported by multiple UAVs,where the first layer of user UAVs can perform tasks such as area coverage, and the second layer of MEC UAVs are deployed as flying MEC sever for user UAVs with computing-intensive tasks. In this system, we first divide the user UAVs into multiple clusters, and transmit the tasks of the cluster members(CMs) within a cluster to its cluster head(CH). Then, we need to determine whether each CH’ tasks are executed locally or offloaded to one of the MEC UAVs for remote execution(i.e., task scheduling), and how much resources should be allocated to each CH(i.e., resource allocation), as well as the trajectories of all MEC UAVs.We formulate an optimization problem with the aim of minimizing the overall energy consumption of all user UAVs, under the constraints of task completion deadline and computing resource, which is a mixed integer non-convex problem and hard to solve. We propose an iterative algorithm by applying block coordinate descent methods. To be specific, the task scheduling between CH UAVs and MEC UAVs, computing resource allocation, and MEC UAV trajectory are alternately optimized in each iteration. For the joint task scheduling and computing resource allocation subproblem and MEC UAV trajectory subproblem, we employ branch and bound method and continuous convex approximation technique to solve them,respectively. Extensive simulation results validate the superiority of our proposed approach to several benchmarks.

Enhancing Clustering Stability in VANET: A Spectral Clustering Based Approach

Vehicles can establish a collaborative environment cognition through sharing the original or processed sensor data from the vehicular sensors and status map. Clustering in the vehicular ad-hoc network(VANET) is crucial for enhancing the stability of the collaborative environment. In this paper, the problem for clustering is innovatively transformed into a cutting graph problem. A novel clustering algorithm based on the Spectral Clustering algorithm and the improved force-directed algorithm is designed. It takes the average lifetime of all clusters as an optimization goal so that the stability of the entire system can be enhanced. A series of close-to-practical scenarios are generated by the Simulation of Urban Mobility(SUMO). The numerical results indicate that our approach has superior performance in maintaining whole cluster stability.

Meta-analysis of the effects of 1-methylcyclopropene(1-MCP)treatment on climacteric fruit ripening

1-Methylcyclopropene(1-MCP)is an inhibitor of ethylene perception that is widely used to maintain the quality of several climacteric fruits during storage.A large body of literature now exists on the effects of 1-MCP on climacteric fruit ripening for different species and environmental conditions,presenting an opportunity to use meta-analysis to systematically dissect these effects.We classified 44 ripening indicators of climacteric fruits into five categories:physiology and biochemistry,quality,enzyme activity,color,and volatiles.Meta-analysis showed that 1-MCP treatment reduced 20 of the 44 indicators by a minimum of 22%and increased 6 indicators by at least 20%.These effects were associated with positive effects on delaying ripening and maintaining quality.Of the seven moderating variables,species,1-MCP concentration,storage temperature and time had substantial impacts on the responses of fruit to 1-MCP treatment.Fruits from different species varied in their responses to 1-MCP,with the most pronounced responses observed in rosaceous fruits,especially apple,European pear fruits,and tropical fruits.The effect of gaseous 1-MCP was optimal at 1μl/l,with a treatment time of 12–24 h,when the storage temperature was 0℃for temperate fruits or 20℃for tropical fruits,and when the shelf temperature was 20℃,reflecting the majority of experimental approaches.These findings will help improve the efficacy of 1-MCP application during the storage of climacteric fruits,reduce fruit quality losses and increase commercial value.