PARAMETERIZATION OF MOBILIZATION AND TRANSPORT OF SAND-DUST DURING BLACK STORM AND MESOSCALE NUMERICAL EXPERIMENTS

The typical black storms or sand-dust storms in the northwestern China are generated and developed through an interaction between the specific large scale circulation pattern and mesoseale systems.The passing by/over a huge sand-abundant desert of a strong cold front with intensive frontal zone at mid and lower levels is a necessary condition for the formation and development of a black storm or a severe sand-dust storm.In order to investigate the mechanism of the sand-dust mobilization,transport and sedimentation during the black or sand-dust storms,a parameterization scheme of sand-dust source-sink terms and an equation of transport for the sand-dust were proposed and incorporated into the MM4 mesoscale model.The modified MM4 model was applied to the“May 1993”black storm case and succeeded in reproducing the evolution of the weather systems associated with the black-storm,the sand-dust concentration at surface layer and its vertical distribution,and the sand-dust sedimentation and transport.Our results show that the numerical simulating method by using a mesoscale model,with inclusion of an equation of the sand-dust transport and a parameterization scheme of the sand-dust source-sink terms,is a promising approach to study the mechanism for sand-dust mobilization,transport and sedimentation during a sand-dust storm event.

Single crystal growth and transport properties of narrow-bandgap semiconductor RhP_(2)

We report the growth of high-quality single crystals of RhP_(2),and systematically study its structure and physical properties by transport,magnetism,and heat capacity measurements.Single-crystal x-ray diffraction reveals that RhP_(2) adopts a monoclinic structure with the cell parameters a=5.7347(10)A,b=5.7804(11)A,and c=5.8222(11)A,space group P2_(1)/c(No.14).The electrical resistivityρ(T)measurements indicate that RhP_(2) exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions,respectively.The temperaturedependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration.We find that RhP_(2) has a high mobilityμ_(e)~210 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_(e)~3.3×10^(18)cm^(3) at 300 K with a narrow-bandgap feature.The high mobilityμ_(e) reaches the maximum of approximately 340 cm^(2)·V^(-1)·s^(-1)with carrier concentrations n_^(e)~2×10^(18)cm^(-3)at 100 K.No magnetic phase transitions are observed from the susceptibilityχ(T)and specific heat C_(p)(T)measurements of RhP_(2).Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.

TiO_(2)Electron Transport Layer with p-n Homojunctions for Efficient and Stable Perovskite Solar Cells

Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.

Flex Ethernet Technology and Application in 5G Mobile Transport Network

With the advent of 5G era,the rise of cloud services,virtual reality/virtual reality(AR/VR),vehicle networking and other technologies has put forward new requirements for the bandwidth and delay of the bearer network.Traditional Ethernet technology cannot meet the new requirements very well.Flex Ethernet(FlexE)technology has emerged as the times require.This paper introduces the background,standardization process,functional principle,application mode and technical advantages of FlexE technology,and finally analyses its application prospects and shortcomings in 5G mobile transport network.

A Review on Mobile and Sensor Networks Innovations in Intelligent Transportation Systems

Rapid developments of mobile technologies, data acquisition and big data analytics, and their integration with critical application domains such as transportation systems have the potential to produce more efficient, real-time, intelligent and safe transportation infrastructure. To increase the quality of transportation services, wireless sensor networks, mobile phones, crowd sourcing, RFID and Bluetooth technologies are being used. We surveyed innovations that were transformed from ideas in research labs into commercial systems in practical use. In this paper, we present some innovative mobile technologies, services and platforms that are being used in modern transportation applications including traffic data acquisition, traffic management and control, route optimizations, infrastructure redesign, road safety and enhancing user experience.

Redesign of Motorized and Non-motorized Transport in Cities and Sustainable Mobility

Redesign of motorized and non-motorized transport in cities and sustainable mobility possibilities and utilization of already occupied areas for motorized and non-motorized transport in cities. Reserved area for public transport may be the redesign much more to take advantage of without taking up new space in cities. Redesigned solutions shown in the work of public mass transport and the redesign of non-motorized transport, bicycle and pedestrian paths point to the improved use and safety of movement of passengers, cyclists and pedestrians. This paper presents five redesigned concept designs as improving existing forms of transport and movement of cyclists and pedestrians in cities. Redesigned conceptual designs of motorized and non-motorized transport in cities should serve as ideas for the growing problems of urban development in the segment of insufficient surface for pedestrians and cyclists, as well as sustainable mobility transport people in the city.

Ensuring Rural Mobility through Demand Responsive Transport, Experiences from Austria

Embedded in an INTERREG IVc project called Flexible Transport Services （FTS） and Information and Communication Technology （ICT） platform for Eco-Mobility in urban and rural European areas （acronym： FLIPPER）, the University of Natural Resources and Applied Life Sciences in Vienna, Austria, analysed impacts of Flexible Transport Services focusing on Demand Responsive Public Transport （DRT）. This includes the analysis of site characteristics, the existing mobility demand, accessibility, area needs, current environmental impact, operational, financial and organisational constraints; designing of the service and definition of the supporting organisational measures required. Examples of realised services in Alpine areas in Austria confirm the effects on people＇s daily mobility and all its consequences towards society and environment. Main effects are the decrease of public funding needs and ensuring a basic transport supply even in rural areas. Additionally, there is a strong component of social inclusion in this service, increasing the quality of life capable to contribute to the deceleration of the out migration. As secondary effects, economic effects and environmental effects can be observed. The potential of these services are not fully utilised today and can be achieved through further extensions of service area as well as technical developments.

基于改进蝙蝠算法的多目标移动储能调度

在大规模电动汽车的随机充电等因素的影响下,电网峰谷差等问题突出。首先,计算所需多类型移动储能(电动汽车、移动储能车、氢燃料发电车)调度功率,考虑交通能耗,建立各类移动储能模型。其中,针对电动汽车交通能耗,根据电价对用户参与意愿的影响,建立相应的补贴体系。其余类型则只计及交通能耗成本。然后,建立以的配电网负荷峰谷差、新能源利用率、配电网运行成本为目标,利用超平面的概念自适应地确定不同目标函数的权重,将多目标归一化,建立三类移动储能协调调度模型。而后,使用改进蝙蝠算法求解,得到多类型移动储能协同调度的方案。其中,基本蝙蝠算法引入柯西变异逆累积分布函数等改进,得到改进蝙蝠算法,该算法有效提升优化速度、全局搜索能力。最后,在IEEE33节点系统中,进行仿真验证,结果证明了该调度方案的有效性。

考虑信息年龄的无人机辅助智能交通系统计算卸载优化

该文考虑无人机(UAV)交通监测与移动边缘计算(MEC)技术结合的智能交通系统。为了保障系统中数据时效性并且降低系统能耗,提出计及信息年龄(AoI)的UAV计算卸载优化方法。首先,建立UAV辅助的MEC系统模型,允许MEC服务器缓存常用的应用程序并为UAV提供计算卸载,以支持UAV执行交通监测任务。通过联合优化UAV任务卸载决策、UAV上下行通信带宽分配以及被卸载任务的计算资源分配,最小化所有UAV与MEC服务器的总能耗,同时满足AoI与资源容量等约束条件。其次,系统能耗最小化问题是混合整数非凸优化问题,因此采用离散化和线性化手段,快速获得问题的近似最优解,并设计离散点生成算法来调节近似误差。最后,仿真结果表明,即使对于大型的非凸问题,所提方法也能够快速得到近似最优解,并且可以在不同的任务场景中满足AoI等约束条件,最大限度降低系统能耗。仿真结果验证了所提方法的有效性。

硫铅处理下伴矿景天对铅的耐受性与积累性研究

【目的】探明土壤在硫(S)铅(Pb)处理下,伴矿景天生长性状变化情况及对重金属Pb的耐受性与积累性,为Pb污染土壤植物修复提供依据。【方法】以伴矿景天为研究对象,采用随机区组试验,研究不同Pb浓度[Pb(CH_(3)COO)2为0 mg、200 mg、400 mg、800 mg、1600 mg]和S浓度(Na_(2)SO_(4)为0 mg、50 mg、100 mg)对伴矿景天的株高、叶长、叶宽、根长、地上干重、根干重和Pb含量的影响及Pb耐受性和富集性的响应。【结果】在相同Pb浓度处理下,随S浓度增加,伴矿景天株高、叶长和根长整体呈增高趋势,在Pb 0 mg/kg、S 100 mg/kg处理下,根长最长,达6.50 cm。地上部干重以Pb 1600 mg/kg、S 50 mg/kg处理最小,根干重以Pb 1600 mg/kg、S 100 mg/kg处理最小。地上部Pb含量以Pb 1600 mg/kg、S 50 mg/kg处理最大,为1654.88 mg/kg;根系Pb含量以Pb 800 mg/kg、S 50 mg/kg处理最大,为1070.42 mg/kg。伴矿景天地上部干重与根干重呈极显著正相关关系,叶长与叶宽呈极显著正相关关系。伴矿景天的Pb富集系数在相同S浓度下,随Pb浓度增加而减小,转运系数、转运量系数总体随Pb浓度增加而减小;在相同Pb浓度处理下,富集系数随S浓度增高而增加,富集系数、转运系数和转运量系数、迁移率最高分别为11.04、2.88、30.64和74.24%。【结论】伴矿景天在铅胁迫下外施硫可缓解地上部、根生物量和株高的减少,并提高植株对铅的富集系数,外施硫是促进伴矿景天吸收重金属的有力措施。

基于改进浮动单元的城市职住平衡时间尺度估计——以广州市为例

已有研究对城市职住平衡的测度往往存在可塑性面积单元问题,且忽略了交通网络在职住联系中的媒介作用。提出一种改进的浮动单元法,构建基于道路和城市轨道交通网络的数据集,以时间为职住分析尺度生成浮动单元,运用手机信令数据对职住平衡进行测度。以广州市为例,对就业中心和居住区的职住平衡时间尺度进行估计。研究发现:广州市中心城区职住平衡时间尺度分布呈圈层式空间特征,职住平衡时间尺度从一级就业中心向外围先减小再增大;城市轨道交通缩小了就业中心的职住平衡时间尺度;一级、二级(不处于一级就业中心的辐射范围内)和三级就业中心的职住平衡时间尺度分别为32~40 min、14~28 min和10~20 min,而居住组团的职住平衡时间尺度主要依附于就业中心且受到城市轨道交通的影响。最后,提出在合适的时间尺度下对职住空间结构进行评估和优化住房和就业等资源配置,并重视城市轨道交通对职住空间结构的影响。

解析出行即服务(MaaS)及其在我国的发展对策研究

针对当前国内出行即服务发展过程中存在的认识误区,本文从国内外MaaS发展情况和具体的实践工作出发,全面解析了出行即服务的内涵、外延及主要特性;阐述了按照服务范围不同和服务目的差异的出行即服务系统分类,并提出了初级、中级、高级和理想级四种形态分级。从我国实情出发,提出中国式出行即服务未来发展需提升战略认识、加强规划引领、强化三网融合、开展先行先试以及成立区域性联盟等对策。

智能网联环境下单交叉口车辆轨迹优化

为了提高信号灯前车辆的通行效率,改善交通流整体运行水平,本文从减少车辆延误和降低燃油消耗两个角度入手,在智能网联环境下,提出了一种车辆编组识别算法和针对编组头车的多目标线性轨迹优化模型(MOLP-pl)。首先对智能驾驶员跟驰模型(IDM)进行改进,调整车辆状态,减少车辆随机到达状态下车辆速度和车头时距分布的差异,同时为后续MOLP-pl轨迹优化模型的运行提供先决条件。在此基础上,以车辆编组为优化单元,通过车辆编组识别算法识别编组头车和跟随车辆,将编组头车的行驶轨迹作为优化对象并建立相应的数学模型。为了提高车辆轨迹优化模型的求解效率和精度,对其进行线性化重构,采用线性求解器计算编组头车加速度,构建编组头车最佳时空轨迹,然后,利用IDM跟驰模型计算跟随车辆的行驶速度,从而使编组车辆最大效率的通过交叉口。最后,利用SUMO构建的仿真实验表明:本研究提出的车辆轨迹优化算法可显著提高信号灯前车辆的通行效率,在三种不同的交通饱和度条件下,相对于无速度引导场景,车辆延误分别降低了8.56%、12.42%、64.79%,燃油消耗分别降低了17.21%、18.34%、12.64%;相对于逻辑控制场景,延误分别降低了-1.31%、2.63%、60.83%,燃油消耗分别降低了2.47%、7.91%、2.28%。

基于移动性导向的公交网络可达性研究

公交优先战略主要偏重于网络可达性优化,通过提高区域线网密度和站点密度可提升居民出行的便利性,但缺少对公交资源调度及移动性导向考虑。为弥补上述缺陷,首先将公交出行过程分为乘坐、换乘、候车等3个阶段,提出了一种涵盖3个阶段的区域公共交通可达性指标体系及测算方法;使用Pearson相关系数描述可达性指标与移动性水平的关联模式,采用K-means聚类算法划分关联模式,挖掘城市区域差异性和以移动性提升为导向的关键可达性要素;并以杭州市为例对该算法进行了案例分析。研究结果表明:公共交通的高可达性并非会带来移动性水平的必然提升,针对这种非一致性提出了分区域的公交网络发展策略。

手机信令数据在职住空间、出行行为和交通碳排放研究中的应用进展与前景

手机信令数据具有覆盖范围广、获取成本低、时空精度较高、稳定实时追踪等优势,能够有效识别大规模人群的空间活动和出行特征,已成为应用最广泛的交通大数据类型之一。文章在手机信令数据的分类和特征基础上,总结了其在职住空间关系和交通出行行为研究中的技术应用,随后结合上述应用成果和已有文献对其在交通碳排放研究中的应用潜力和场景进行了探讨,最后总结了手机信令数据在职住空间、出行行为和交通碳排放研究中的应用框架、应用机遇与挑战以及未来研究内容与技术创新方向。目前,手机信令数据在职住空间领域中的应用包括职住地识别、职住关系和通勤网络特征及其影响因素解析,在出行行为领域中的应用包括驻留-出行识别、出行方式和路径识别,以及人群移动普适规律解析。以上技术应用能够有效服务交通碳排放领域研究,为交通碳排放测算以及城市空间结构、居民出行行为对交通碳排放的影响研究奠定了基础。未来,相关研究应进一步关注长时序动态追踪、大范围对比分析以及人口和交通新现象研究,并注重多源数据的融合、传统方法与机器学习的结合以及数字孪生模型的构建。

Public transport inclusion and active aging: A systematic review on elderly mobility

Global aging has brought attention to addressing the elderly mobility dilemma,and a commitment to address inclusive transport in aging.Transport inclusion for older adults aims at establishing an age-friendly transport system.As a direct policy goal and promoting active aging as an indirect social goal,to help older populations gain access to transport and social opportunities.Based on the analysis of scientific knowledge mapping over the past 30 years,this study visualizes the hotspots and trends in elderly mobility research.Through a qualitative analysis of 138 papers,this paper reviews the theoretical foundations for transport inclusion and three themes of elderly mobility research,proposes a framework for public transport(PT)inclusion research as well as future research directions.The study suggests that transport inclusion can help enhance elderly health,social participation,and subjective well-being.It can improve their travel opportunities for active aging in four ways:opportunity accessibility,physical accessibility,age-friendly informationalization,and cost affordability.Future research should pay attention to examining the mechanism of perceived transport inclusion on active aging,expanding the multilevel research space of the capability approach(CA),and exploring the subjectiveobjective integrated research model for PT inclusion.This research contributes to the overall knowledge of the theoretical and empirical researches on PT inclusion for the elderly and promotes the integrated application of interdisciplinary knowledge in the field.

Large-scale interplant exchange of macromolecules between soybean and dodder under nutrient stresses

Parasitic plants and their hosts communicate through haustorial connections.Nutrient deficiency is a common stress for plants,yet little is known about whether and how host plants and parasites communicate during adaptation to such nutrient stresses.In this study,we used transcriptomics and proteomics to analyze how soybean(Glycine max)and its parasitizing dodder(Cuscuta australis)respond to nitrate and phosphate deficiency(-N and-P).After-N and-P treatment,the soybean and dodder plants exhibited substantial changes of transcriptome and proteome,although soybean plants showed very few transcriptional responses to-P and dodder did not show any transcriptional changes to either-N or-P.Importantly,large-scale interplant transport of mRNAs and proteins was detected.Although the mobile mRNAs only comprised at most 0.2%of the transcriptomes,the foreign mobile proteins could reach 6.8%of the total proteins,suggesting that proteins may be the major forms of interplant communications.Furthermore,the interplant mobility of macromolecules was specifically affected by the nutrient regimes and the transport of these macromolecules was very likely independently regulated.This study provides new insight into the communication between host plants and parasites under stress conditions.

Mobile-GIS中的数据组织模型研究

mob ile-GIS是GIS的全新发展领域,从应用的角度评述了移动服务中的数据特点和各种数据模型的原理及适用领域。不同的数据模型造成部门间数据难以共享,为此本文提出了一种集成数据模型,能使不同模型相互转化,提高数据共享程度。