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 theγ-charged-particle coincidence technique to measure the proton andα exit channels of ^(24)Mg.Technical details of the ^(23)Na+p thick-target inverse kinematics experiment and analysis are presented herein.

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。

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. .

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。

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.

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.

Routing Protocol for Heterogeneous FANETs with Mobility Prediction

In recent years,with the growth in Unmanned Aerial Vehicles(UAVs),UAV-based systems have become popular in both military and civil applications.In these scenarios,the lack of reliable communication infrastructure has motivated UAVs to establish a network as flying nodes,also known as Flying Ad Hoc Networks(FANETs).However,in FANETs,the high mobility degree of flying and terrestrial users may be responsible for constant changes in the network topology,making end-to-end connections in FANETs challenging.Mobility estimation and prediction of UAVs can address the challenge mentioned above since it can provide better routing planning and improve overall FANET performance in terms of continuous service availability.We thus develop a Software Defined Network(SDN)-based heterogeneous architecture for reliable communication in FANETs.In this architecture,we apply an Extended Kalman Filter(EKF)for accurate mobility estimation and prediction of UAVs.In particular,we formulate the routing problem in SDN-based Heterogeneous FANETs as a graph decision problem.As the problem is NP-hard,we further propose a Directional Particle Swarming Optimization(DPSO)approach to solve it.The extensive simulation results demonstrate that the proposed DPSO routing can exhibit superior performance in improving the goodput,packet delivery ratio,and delay.

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.

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.

Unsourced Multiple Access for 6G Massive Machine Type Communications

Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy efficiency.Based on the analysis of the 6G MTC key performance indicators(KPIs)and scenario characteristics,this paper summarizes its requirements for radio access networks.Following this,the existing multiple access models are analyzed under these standards to determine UMA's advantages for 6G MTC according to its design characteristics.The critical technology of UMA is the design of its multiple-access coding scheme.Therefore,the existing UMA coding schemes from different coding paradigms are further summarized and compared.In particular,this paper comprehensively considers the energy efficiency and computational complexity of these schemes,studies the changes of the above two indexes with the increase of access scale,and considers the trade-off between the two.It is revealed by the above analysis that some guiding rules of UMA coding design.Finally,the open problems and potentials in this field are given for future research.

Ultrahigh accelerating gradient and quality factor of CEPC 650 MHz superconducting radio-frequency cavity

Two 650 MHz single-cell superconducting radio-frequency(SRF)cavities used for the Circular Electron Positron Collider(CEPC)were studied to achieve a high accelerating gradient(E_(acc))and high intrinsic quality factor(Q_(0)).The 650 MHz single-cell cavities were subjected to a combination of buffered chemical polishing(BCP)and electropolishing(EP),and their E_(acc) exceeded40 MV/m.Such a high E_(acc) may result from the cold EP with more uniform removal.BCP is easy,cheap,and rough,whereas EP is complicated,expensive,and precise Therefore,the combination of BCP and EP investigated in this study is suitable for surface treatments of mass SRF cavities.Medium temperature(mid-T)furnace baking was also conducted,which demonstrated an ultrahigh Q_(0) of 8×10^(10) at 22 MV/m for both cavities,and an extremely low BCS resistance(R_(BCS))of~1.0 nΩwas achieved a2.0 K.

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.

Adaptive 3D Routing Protocol for Flying Ad Hoc Networks Based on Prediction-Driven Q-Learning

The routing protocols are paramount to guarantee the Quality of Service(QoS)for Flying Ad Hoc Networks(FANETs).However,they still face several challenges owing to high mobility and dynamic topology.This paper mainly focuses on the adaptive routing protocol and proposes a Three Dimensional Q-Learning(3DQ)based routing protocol to guarantee the packet delivery ratio and improve the QoS.In 3DQ routing,we propose a Q-Learning based routing decision scheme,which contains a link-state prediction module and routing decision module.The link-state prediction module allows each Unmanned Aerial Vehicle(UAV)to predict the link-state of Neighboring UAVs(NUs),considering their Three Dimensional mobility and packet arrival.Then,UAV can produce routing decisions with the help of the routing decision module considering the link-state.We evaluate the various performance of 3DQ routing,and simulation results demonstrate that 3DQ can improve packet delivery ratio,goodput and delay of baseline protocol at most 71.36%,89.32%and 83.54%in FANETs over a variety of communication scenarios.

5-氟尿嘧啶和卡培他滨对中国患者的心脏毒性:一项前瞻性研究

背景与目的已有许多研究报道5-氟尿嘧啶(5-Fluorouracil,5-FU)和卡培他滨相关的心脏毒性,严重程度从无症状心电图(electrocardiography,ECG)异常到严重心肌梗塞而不同。目前为止,对中国恶性肿瘤患者的这种心脏毒性尚无研究。本研究旨在前瞻性地对多个中心招募的癌症患者进行5-FU和卡培他滨相关心脏毒性的发生率和临床表现进行评估。方法在完成研究的527例患者中,196例接受基于5-FU的化疗,331例接受基于卡培他滨的化疗并以其为一线或辅助治疗。在治疗期间和长达28 d的随访期间对所发生的不良反应进行记录。疗效测量指标包括心电图、心肌酶、心肌肌钙蛋白、脑钠肽和超声心动图。使用单因素分析和logistic回归方法进行亚组分析和鉴定与两种药物的心脏毒性相关的显著性独立变量。结果 527例患者中有161例(30.6%)出现心脏毒性。卡培他滨组的心脏毒性发生率为33.8%(112/331),显著高于5-FU组25%(49/196)的发生率(P=0.0042)。110/527患者(20.9%)发生心律失常,105/527(19.9%)发生缺血性改变,而只有20/527患者(3.8%)出现心力衰竭,6/527患者(1.1%)出现心肌梗塞。既往的心脏病、高血压、卡培他滨为基础的化疗和治疗时间被确定为与心脏毒性相关的显著风险因素。优势比分别为15.7(心脏病史vs.无病史)、1.86(卡培他滨vs. 5-FU)、1.06(5–8个化疗周期vs. 1–4个化疗周期)和1.58(高血压vs.无高血压)。结论氟嘧啶类药物在中国人群中引起的心脏毒性可能在临床实践中被低估。建议密切监测患者,尤其是对心脏毒性高风险的患者。可能的风险因素包括治疗持续时间、基于卡培他滨的化疗、既往心脏病史和高血压史。

6NG-16型重力式谷糙分离机的设计与研究

为提高谷糙分离机的传动性能,针对设计的重力式谷糙分离机分析最小传动角与极位夹角、α角之间的数学关系,并分析曲柄滑块机构最小传动角的变化规律。得出在不同极位夹角情况下最小传动角的变化曲线。研究结果表明,在运动幅度为90 mm,极位夹角为8.57°时,取α角为11.29°,最小传动角获得最大值58.9°,可以满足谷糙的分离要求。

Science for This Age: Paradigm Shifts and Global Challenges

Whether the goal is to meet global challenges or to enable a paradigm shift,it is always essential for science to move beyond conventional thinking.Moreover,the mutually beneficial interactions between global challenges and paradigm shifts require a great deal of effort.To this end,it is imperative for the scientific community not only to respond to major challenges by shifting paradigms in science but also to drive paradigm shifts in science by responding to major challenges.This aim sets a higher bar for scientists as,in order to achieve it,we must properly identify the scientific questions in research and better utilize existing knowledge.At present,however,we are not paying sufficient attention to this aim,nor are we sufficiently competent in this regard.It is essential for the global scientific community to pay more attention to these interconnected issues of global challenges and paradigm shifts.