Regional Variability of Climate Change Hot-Spots in East Asia

The regional climate change index （RCCI） is employed to investigate hot-spots under 21st century global warming over East Asia. The RCCI is calculated on a 1-degree resolution grid from the ensemble of CMIP3 simulations for the B1, AIB, and A2 IPCC emission scenarios. The RCCI over East Asia exhibits marked sub-regional variability. Five sub-regional hot-spots are identified over the area of investigation： three in the northern regions （Northeast China, Mongolia, and Northwest China）, one in eastern China, and one over the Tibetan Plateau. Contributions from different factors to the RCCI are discussed for the sub-regions. Analysis of the temporal evolution of the hot-spots throughout the 21st century shows different speeds of response time to global warming for the different sub-regions. Hot-spots firstly emerge in Northwest China and Mongolia. The Northeast China hot-spot becomes evident by the mid of the 21st century and it is the most prominent by the end of the century. While hot-spots are generally evident in all the 5 sub-regions for the A1B and A2 scenarios, only the Tibetan Plateau and Northwest China hot-spots emerge in the B1 scenario, which has the lowest greenhouse gas （GHG） concentrations. Our analysis indicates that subregional hot-spots show a rather complex spatial and temporal dependency on the GHG concentration and on the different factors contributing to the RCCI.

Study of the asymmetry of hot-spot self-emission imaging of inertial confinement fusion implosion driven by high-power laser facilities

Implosion asymmetry is a crucial problem quenching ignition in the field of inertial confinement fusion.A forward-calculation method based on 1D and 2D hydrodynamic simulations has been developed to generate and study the x-ray images of hot-spot self-emission,indicating asymmetry integrated over the entire drive pulse.It is shown that the x-ray imaging photon energy should be higher to avoid the influence of the remaining shell.The contour level(percentage of the maximum emission intensity)and spatial resolution should be as low as possible,optimally less than 20%and 3μm,for characterization of higher-mode signatures such as Ps-P12 by x-ray self-emission images.On the contrary,signatures of lower-mode such as P2 remain clear at all contour levels and spatial resolutions.These key results can help determine the optimal diagnostics,laser,and target parameters for implosion experiments.Recent typical hot-spot asymmetry measurements and applications on the Shenguang 100 kJ class laser facility are also reported.

Distribution of Panama’s narrow-range trees:are there hot-spots?

Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small populations.Assessing risks for these species is challenging,however,especially in tropical flora where their sparse populations seldom appear in traditional plots and inventories.Here,we utilize instead large scale databases that combine tree records from many sources to test whether the narrow-range tree species of Panama are concentrated at certain elevations or in certain provinces.Past investigations have suggested that the Choco region of eastern Panama and the high mountains of western Panama may be potential hotspots of narrow-range tree species.Methods:All individual records were collected from public databases,and the range size of each tree species found in Panama was estimated as a polygon enclosing all its locations.Species with ranges<20,000 km^(2) were defined as narrow endemics.We divided Panama into geographic regions and elevation zones and counted the number of individual records and the species richness in each,separating narrow-range species from all other species.Results:The proportion of narrow endemics peaked at elevations above 2000 m,reaching 17.2% of the species recorded.At elevation<1500 m across the country,the proportion was 6-11%,except in the dry Pacific region,where it was 1.5%.Wet forests of the Caribbean coast had 8.4% narrow-range species,slightly higher than other regions.The total number of narrow endemics,however,peaked at mid-elevation,not high elevation,because total species richness was highest at mid-elevation.Conclusions:High elevation forests of west Panama had higher proportions of narrow endemic trees than low-elevation regions,supporting their hot-spot status,while dry lowland forests had the lowest proportion.This supports the notion that montane forests of Central America should be a conservation focus.However,given generally higher diversity at low-to mid-elevation,lowlands are also important habitats for narrow-range tree species,though conservation efforts here may not protect narrow-range tree species as efficiently.

Discussion of a Failure Hot-Spot Endurance Testing Case for CIGS Thin-Film Photovoltaic Module

This paper describes the use of steady-state solar simulator for CIGS thin-film photovoltaic module hot-spot endurance test. In the study, not only are test procedures of hot-spot endurance test in IEC 61646 discussed, but also how to evaluate the performance of steady-state solar simulator by IEC 60904-9 is presented. Three CIGS thin-film PV modules with the same types are used for hot-spot endurance test in case study. It is found that some of the cell damages and visual defects on tested PV modules are clearly observed.

Analysis of structural hot-spot stress in orthotropic plates

On the basis of the actual steel deck structure of Taizhou Bridge, this paper carries out hot-spot stress analysis on some key spots by using the finite element model which simulates local structure of orthotropic steel bridge decks. A finite element model is established for local structure of orthotropic steel bridge decks, and in the analysis of linear elasticity of the structure, face load is employed to simulate the loads from vehicle wheels. Analysis results show that main stresses are relatively heavy at the joints between diaphragm plates, top plates and U-shaped ribs and the joints between diaphragm plates and U-shaped ribs. These joints shall be regarded as key points for hot-spot stress analysis. Different mesh densities are adopted in the finite element model and the main stresses at different hot spots are contrasted and linear extrapolation is carried out using extrapolation formulae. Results show that different mesh densities have different influences on the hot-spot stresses at the welded seams of U-shaped ribs. These influences shall be considered in calculation and analysis.

The Lower Cretaceous Giant Dyke Swarms in the Arctic and Its Significance for linking of Siberia-Iceland Hot-Spot Track

Siberia-Iceland hot-spot track is the one of hot-spot track preserved on continent.Although this hot-spot track has clear plume"heads"-Siberia large igneous province,owing to thick continental lithosphere,its continuing

Voltage-Based Hot-Spot Detection Method for Defective Cell in Photovoltaic Module Using Projector

This paper proposes a voltage-based hot-spot detection method for defective cells in PV module using projector. The presence of internal crystal defects is one of the main causes of hot-spot phenomenon in PV modules. Authors previously investigated the physical characteristics of hot-spot phenomenon referring to internal crystal defect. Based on it, a hot-spot detection method named as current-based SRC （self reverse current） detection method is developed. However, it becomes extraordinarily complicated to determine the defective cells under low illumination. In order to avoid this disadvantage, authors improve the SRC detection method by applying voltage. From the feasibility experiment results, it is confirmed that by calculating cell HSI （hotspots index） with voltage, the PV modules with defective cells can be prospectively excluded even under low illumination.

Hot-Spot Detection System with Correction of Operating Point for PV Generation System

Currently, the production and the number of installations of PV （photovoltaic） modules have been increasing rapidly because of a feed-in tariff in Japan. Accordingly, the number of failures has also increased. Many failures are a result of the Hot-Spot phenomenon in which defective cell becomes hot when shadow occurs on the cell, On the other hand, if shadow occurs on normal cell, there are cases that P＆O method that is MPPT （maximum power point tracking） control method incorporated in conventional PV system cannot track maximum power point and generated power decreases. The correspondence is required rapidly if these trouble occur. However, conventional PV system monitors generated power, correspondence is impossible by monitoring generated power. Previously, the authors developed real time Hot-Spot detection system that incorporates into PCS （power conditioning system）. Thus, the authors developed plug-in type Hot-Spot monitoring system that includes ＂PV peak shift method＂ and confirmed effectiveness of the system in this time. ＂PV peak shift method＂ loads ＂Scan method＂ that is MPPT control method and measures I-V （current-voltage） characteristic by changing voltage of module from open to short by ＂Scan method＂ on a regular basis. The developed Hot-Spot monitoring system uses slope of I-V characteristic of PV module. Inserting developed system into already installed PV system, Hot-Spot can be easily monitored in real time and PV system can be operated at maximum power point.

THE GEOTHERMAL PULSE OF HOT-SPOT AND ITS DISPERSION PROCESS OVER CHINA-INDIA-BURMA AND CHANGE OF SHORT-TERM CLIMATE

The great gorge of Yarlung Zangbo river is a hot\|spot over earth has been proved by the gravity, geomagnetic, geological, geothermal heat and atmospheric data. Some substances often surge from mantle to the earth surface, which process is not constant and has obvious pulse, characterized by ground temperature over hot\|spot region where is a apparent positive relation in correlation map of the variations of Zedang’s temperature (at 3 2m) in stations over China from 1965 to 1992. It can bring more precipitation here. Out of from the hot spot, there are positive and negative axes around the hot\|spot and to arrange in circular waves with same distance. The average distant of the axes is about 820km, which prove the pulse propagation would infect the distribution of summer precipitation in China. In the hot\|spot region, the geothermal heat pulse propagation has preference direction. So, it has obvious contribution for summer precipitation in South Ch ina.

基于混合有限元法的油浸式变压器稳态流-热耦合场并行计算方法

针对油浸式变压器2维流-热耦合仿真计算效率低的问题,提出了基于混合有限元法的并行计算方法。首先,在Visual Studio 2019中采用C++语言实现无量纲最小二乘有限元法以及迎风有限元法的串行计算方法。然后,基于图形处理器(graphic processing unit,GPU)实现流体场的并行计算,针对单分区分匝模型对比分析了不同GPU卡在不同网格条件下的并行计算效率,分析结果表明数据规模越大,GPU卡流处理器越多并行效果越好。其次,基于Intel MKL(Intel math kernel library)函数库结合共享存储并行编程(open multi-processing,OpenMP)实现了2维温度场的并行计算,并对比分析了不同网格数量对并行效率的影响。最后,在此基础上提出了根据不同仿真条件的混合并行计算方法,并应用到大型油浸式变压器绕组模型的2维温升热点分析中。结果表明,相较于串行程序,混合有限元并行计算方法的加速比达到了69.5,实验测试结果进一步验证了并行计算结果的准确性,研究成果为大型油浸式变压器流-热耦合问题的快速计算奠定了基础。

中国县域数字乡村发展的空间格局及驱动因素研究

基于北京大学新农村发展研究院公布的2018年中国1880个县域数字乡村指数数据,采用探索性空间数据分析、冷热点分析和地理探测器等方法,考察中国县域数字乡村发展的空间格局及其驱动因素。结果表明:1)中国县域数字乡村发展水平呈现明显的“梯度化”特征,数字乡村发展水平由东部向西部逐渐递减,数字乡村在长三角地区呈“片状分布”,而在西部地区和东北地区呈“点状分布”。2)中国县域数字乡村发展呈现明显的空间集聚特征,在经济发展水平较高、网络基础设施较为完善的长三角地区形成“高-高”集聚。数字乡村发展呈现次热点区和热点区围绕高热点区集聚的“中心-外围”结构形态。在热点区与冷点区之间形成“T”字形狭长地带,将热点区与冷点区分隔开。3)中国县域数字乡村发展的总体基尼系数为0.0359,其中数字乡村的区域间差距是数字乡村发展总体差异的主要来源。4)产业经济、人口教育、财政金融和基础设施的空间分异特征对数字乡村空间分布具有较强的影响。

基于布里渊光时域峰值边沿分析的变压器绕组局部热点检测

变压器绕组的温度分布一直是电网运行人员重点关注的对象。与传统传感器相比,分布式光纤传感具有抗电磁干扰能力强、可实现分布式测量等优势,其中布里渊光时域分析技术(BOTDA)的性能稳定,适用于大多数场景,但BOTDA的空间分辨率为m级,难以分辨绕组运行中的局部热点。该文从布里渊散射增益谱的机理入手,利用双峰拟合算法,并结合对异常峰值曲线的边沿分析,提出了一种在不增加系统硬件复杂度的基础上提升BOTDA空间分辨率的方法,以满足局部热点检测要求。通过对光纤沿线不同位置、不同热点长度及不同热点温度下的模拟试验验证了该方法的有效性,在实验室条件下可将准确传感的热点长度提升至原空间分辨率的一半以内。基于变压器实际绕组的局部升温试验,实现了绕组异常热点的精确定位和长度感知,并准确解调了绕组局部热点的温度,进一步验证了该方法的实际可行性和检测优越性,温度相对误差控制在5%以内,为提高变压器绕组温度在线监测的经济性和可行性提供新的思考,同时也为变压器绕组局部故障的提前感知和预警提供了新的思路。

基于空间自相关的常规城市公交车辆危险驾驶热点路段识别

为了获得公交危险驾驶状态的空间分布特征,采用空间自相关性分析方法,识别危险驾驶状态的空间集聚性,确定危险驾驶状态热点路段,并对显著性影响因素进行分析。首先,采集4个季度各1周公交车辆卫星定位数据样本,修复重复数据、异常数据和缺失数据,并以公交站点为节点划分空间区段,对每个区段进行编号;接着,将速度过快、急加速、急减速和急转弯确定为危险驾驶状态,参照车辆运动学特性获得4种危险驾驶状态阈值,并计算4种危险驾驶状态的统计学指标和全局莫兰指数,结果表明,公交车辆危险驾驶状态具有空间集聚性(空间随机分布概率p<0.01,标准差得分值Z>2.58),速度过快状态(全局莫兰指数为0.731)的空间集聚性最为显著;然后,分别对4种危险驾驶状态进行局部空间自相关性分析,绘制了90%、95%和99%置信度下的莫兰散点图和Lisa集聚图,结合城市地图,获得危险驾驶状态的热点路段;最后,选取路段长度、车道数、平直度等9个指标,对比分析了OLS模型、SLE模型、SEM模型和SDM模型的拟合优度,采用SDM模型获得4种危险驾驶状态的显著性影响因素。文中研究结果可为公交车辆危险驾驶状态空间识别、精细化安全运行管理提供理论依据。

气管插管患者拔管后吞咽障碍研究热点的可视化分析

目的 分析气管插管患者拔管后吞咽障碍相关研究的热点及发展趋势。方法 系统检索中国知网、Web of Science数据库中关于气管插管患者拔管后吞咽障碍的研究,运用CiteSpace 5.8R3可视化软件对文献进行分析。结果共纳入中文文献119篇,英文文献408篇,发文量总体呈上升趋势。关键词分析发现,研究热点主要集中在并发症、风险因素、筛查与管理等方面,中文文献形成吞咽障碍、危险因素、气管插管、误吸、营养、吞咽评估共6个聚类,英文文献形成dysphagia(吞咽障碍)、airway management(气道管理)、management(管理)、endotracheal intubation(气管插管)、muscle skeletal(肌肉骨骼)、aspiration(误吸)、cardiac surgery(心脏手术)共7个聚类;关键词突现分析发现,并发症管理和症状评估是拔管后吞咽障碍的研究前沿。结论 气管插管患者拔管后吞咽障碍聚焦于重症、心脏外科术后及颈椎骨折的患者,中英文文献的研究主题及类型存在差异,护理在拔管后吞咽障碍管理中起到重要作用。我国护理工作者今后应借鉴国外经验,以提升患者经口进食的安全性、促进早期恢复经口进食为目的,开发具有特异性的评估工具,制订规范化拔管后吞咽评估与管理流程。

基于高阶空间交互网络的光伏组件热斑故障检测

针对传统红外热斑故障检测算法由于特征表达能力不佳造成算法易受复杂背景干扰以及对密集目标、小目标故障检测精度低的问题,提出一种基于高阶空间交互的光伏组件热斑故障检测网络。首先,设计高阶空间交互模块,并将其引入YOLOv5主干网络进行全局交互建模,提升网络对密集目标的检测精度;其次,为突出复杂背景下故障目标的关键特征,设计基于协同注意力的特征提取模块重构颈部网络;然后,在颈部网络设计多尺度特征增强融合模块以提高检测网络对不同尺度特征的充分利用;最后,设计自适应特征融合检测头以提高模型对小目标的感知能力。实验结果表明,相较于7种经典检测算法,所提出的算法检测精度最高,精度可达84.3%。

面向持久化键值数据库的自适应热点感知哈希索引

针对现有键值数据库存储系统缺乏热点意识,导致系统在高度倾斜的工作负载下性能较差且不可靠,提出了一种自适应热点感知哈希索引模型,该模型基于key值摘要信息实现了一个高性能哈希表。首先,利用key的摘要信息代替key值,压缩key的存储空间,优化哈希表中桶的数据结构;其次,利用CPU的数据级并行技术以及CPU cache line,对哈希表的探查操作进行优化;最后,为解决摘要信息导致key值无法精准比较,需要额外磁盘I/O的问题,设计了一种自适应key值调度算法,该算法根据当前可用内存大小、哈希索引负载以及访问热点情况动态地调整key值的存储位置。在YCSB仿真数据集上进行了实验,实验表明,相较于最先进的哈希表,自适应热点感知哈希索引在相同内存使用率的情况下,将速度提升至1.2倍。

钢-PPUC组合正交异性钢桥面板疲劳性能

为有效解决传统钢桥面病害,提出了钢-聚酯型聚氨酯(钢-PPUC)混凝土组合桥面板结构,开展了正交异性钢桥面板的疲劳性能研究。以马鞍山公铁两用大桥为工程背景,建立局部有限元模型,采用热点应力法获得车轮荷载作用下钢桥面易疲劳开裂部位的应力响应,基于疲劳应力幅进行疲劳强度评估。考虑不同温度、不同铺装层厚度和不同结构形式条件下PPUC铺装层对正交异性钢桥面板疲劳性能的影响。结果表明:高弹性模量的PPUC铺装层对正交异性钢桥面板典型疲劳细节处的应力具有明显的改善作用;顶板与纵肋连接部位疲劳细节应力幅降幅最大,顶板与纵肋连接处桥面板细节、纵肋与横隔板连接处纵肋细节和纵肋对接焊缝细节均满足抗疲劳开裂要求;不同温度作用下的弹性模量变化对典型疲劳细节等效应力幅的影响是非线性的,铺装层厚度变化对典型疲劳细节等效应力幅的影响是近似线性的;为兼顾正交异性钢桥面板受力性能和行车舒适性两方面要求,提出了单层和双层复合型PPUC结构形式,计算得到2种结构形式对各疲劳细节应力幅最大降幅为21%~56%,最小降幅为8%~36%,为钢-PPUC组合桥面板抗疲劳设计提供理论依据。

应急社会动员研究热点与趋势的知识图谱分析

为更准确地为应急社会动员研究提供参考方向,以中国知网(CNKI)数据库中中文社会科学引文索引(CSSCI)期刊收录的296篇应急社会动员研究文献为样本,综合运用文献计量、知识图谱等可视化分析方法,系统分析该领域研究的历年发文数量、期刊分布、发文机构、研究议题与热点、变化趋势等情况。结果表明:2003年以来,应急社会动员研究的年发文数量经历3个阶段的发展,期刊分布日渐广泛,发文机构比较松散;研究议题愈来愈多,主要集中在突发事件响应阶段应急社会动员的触发情景、实施机制和功能效果;热点议题不断涌现,深度广度持续拓展,研究方法相对局限;后续研究发展空间较大,可侧重于应急社会动员的多方法、全过程、智慧化等研究内容。

基于Web of Science的瑞马唑仑研究热点与发展趋势的可视化分析

目的通过文献计量和知识图谱分析,探究Web of Science核心数据库中关于瑞马唑仑的研究热点和发展趋势,为后续研究提供方向。方法检索Web of Science核心库,分别以“remimazolam”和“CNS7056”为主题词进行检索,时间为建库至2023年8月31日,运用CiteSpace及VOSViewer对检索到的文献除重后,对关键词、高被引文献等进行可视化分析和比较。结果收集到268篇有效文章,发文量在2020年呈指数级增长。关键词分析显示诊疗操作镇静、镇静麻醉药物及其引起的不良事件是目前的研究热点。结论研究集中于瑞马唑仑在诊疗操作镇静中的应用及不良事件等相关;其镇静有效性及安全性是研究焦点。

基于知识图谱的国内紫砂研究动态及趋势分析

为深入了解国内紫砂领域的研究现状,预测未来研究趋势,以1992-2022年中国知网数据库收录的305篇研究紫砂的核心期刊论文为对象,利用文献计量法、词频分析法等,并借助CiteSpace软件绘制知识图谱,对此领域高产作者、高产机构、关键词热点、关键词聚类、突现关键词等进行深度剖析。分析结果显示,紫砂研究在30年里取得了一定的成果,其中对紫砂茶壶主体研究的各项聚类是主流热点,文化研究的聚类和材料研究的聚类也是突出的热点。此外,外销紫砂将成为未来的研究前沿,同时紫砂产业研究极具发展潜力。CiteSpace可视化分析可以更全面地把握国内紫砂研究的动态过程,研究者可以根据知识图谱中极具影响力的热点关键词、集群、突现词等,扩展和深化现有知识,获得研究领域的新见解。