Giant magneto field effect in up-conversion amplified spontaneous emission via spatially extended states in organic-inorganic hybrid perovskites

Up-conversion lasing actions are normally difficult to realize in light-emitting materials due to small multi-photon absorp-tion cross section and fast dephasing of excited states during multi-photon excitation.This paper reports an easily ac-cessible up-conversion amplified spontaneous emission(ASE)in organic-inorganic hybrid perovskites(MAPbBr3)films by optically exciting broad gap states with sub-bandgap laser excitation.The broad absorption was optimized by adjust-ing the grain sizes in the MAPbBr3 films.At low sub-bandgap pumping intensities,directly exciting the gap states leads to 2-photon,3-photon,and 4-photon up-conversion spontaneous emission,revealing a large optical cross section of multi-photon excitation occurring in such hybrid perovskite films.At moderate pumping intensity(1.19 mJ/cm2)of 700 nm laser excitation,a significant spectral narrowing phenomenon was observed with the full width at half maximum(FWHM)de-creasing from 18 nm to 4 nm at the peak wavelength of 550 nm,simultaneously with a nonlinear increase on spectral peak intensity,showing an up-conversion ASE realized at low threshold pumping fluence.More interestingly,the up-con-version ASE demonstrated a giant magnetic field effect,leading to a magneto-ASE reaching 120%.In contrast,the up-conversion photoluminescence(PL)showed a negligible magnetic field effect(<1%).This observation provides an evid-ence to indicate that the light-emitting states responsible for up-conversion ASE are essentially formed as spatially exten-ded states.The angular dependent spectrum results further verify the existence of spatially extended states which are polarized to develop coherent in-phase interaction.Clearly,using broad gap states with spatially extended light-emitting states presents a new approach to develop up-conversion ASE in organic-inorganic hybrid perovskites.

Charge Transfer Mechanism and Spatial Density Correlation of Electronic States of Excited Zinc (3d⁹) Films

In material science, half filled 3d orbital of transition metals is essentially an important factor controlling characteristics of alloys and compounds. This paper presents a result of the challenge of excitation of inner-core electron system with long lifetime of zinc films. The advanced zinc films with excited inner-core electron, 3dn (n = 9, 8). We report experimental results of XPS measurements of 9 points in the sample along vertical direction, respectively. The most pronounced futures are existence of satellites, which are about 4 eV higher than the main lines. According to the charge transfer mechanism proposed by A. Kotani and K. Okada, it was clarified that the origins of these peaks are c3d9L for the main peak and c3d9 for the satellite, respectively. From the energy difference, δEB, and peak intensity ratio, I+/I-, between c3d9 and c3d10L, the energy for charge transfer, Δ, and mixing energy, T, were estimated. In the region where the intensity of c3d10L becomes large, Δ becomes small, 1.2 Δdc = 5.5 eV and Udd = 5.5 eV. In the analysis along vertical direction, intensity profile of Zn3d9 showed odd functional symmetry and that of Zn3d10L showed even functional symmetry. Only the intensity profile of C1s (288 eV) showed the same spatial correlation with Zn3d9. In our experiment, the sample also showed high mobility of the constituting elements. These suggest that charge conservation in excited zinc atom suggests combination between Zn3d9 and C2-.

Spatial Assessment of the Perception of Environmental Pollution in Rivers State

This study examines the perception of pollution in Rivers state, to find out the inhabitants opinion of how the government is handling pollution in the area. The study used the survey research design and primary data which were collected using copies of questionnaire were the main data used for the study. Data collected were presented using tables and statistical diagrams, while data analysis was achieved using the welch statistics. It was observed that 37.75% of the respondents suggested that the air quality in the area is very bad, suggesting that they were suffering as a result. The main sources of environmental pollution were petroleum refining (44.25%), illegal refining of petroleum products (52.75%) and fumes from vehicles (46%). Also noted was that vast majority of inhabitants (86.75%) were willing to partake in the cleaner environmental process, but they stated that the government was not forceful enough to achieve the pollution free environment in the area. The welch statistics identified that there was no statistically significant difference in the perception of polluted environment in the area at P > 0.05. The study as a result of the findings advocates partnership between government, individuals and NGOs to achieve cleaner and safer environment in the area.

Using a GIS Tool to Map the Spatial Distribution ofPopulation for 2010 in the State of Mexico, Mexico

The present document describes the experience of using a Geography Information System (GIS) tool to map the spatial distribution of the population of the State of Mexico, Mexico, for 2010. Prior to the development of the experience, dif- ferent projects, tools and products, which offered cartographic representations of the population, were presented, se- lecting one that was developed to function in Idrisi Taiga GIS. Likewise, the GIS tool and the process followed to apply it to a case study in the State of Mexico are described. The result is a raster image that shows the distribution of the population on the analyzed state, offering the possibility to identify the zones where the population concentrates and disperses and to produce an opinion from a geographic point of view on what the origin of these distribution patterns is. Among the conclusions from the analysis of results, distinguishable are the applications that the obtained image can have;for instance, the population can be estimated by basins or risk zones by only adding the values of the cells inside these zones. It is also concluded that the degree of detail expressed by the spatial distribution image of the population will depend on several factors, among them the scale and resolution of the input information and the resolution fixed for the output information.

Dynamic Spatial Evolution of Market-oriented Supply Level of State-owned Land

The purpose of this study is to analyze the characteristics of the spatial distribution and change trend of the marketing level of stateowned land supply so as to provide policy recommendations. Method of spatial autocorrelation analysis is employed. The results indicate that the spatial layout of the land supply marketing level is generally dispersed,but it does assemble in some specific area. The correlation between the marketing level of state-owned land supply and the economic development is not statistically significant. But their relations fluctuate obviously. The overall marketing level of state-owned land supply is increasing and spatially concentrated. The expansion rate of marketing has decreased first and then increased and stabilized now. The high-value cluster center of marketing level of state-owned land supply exists all over the country; however the existence probability of the cluster is bigger in undeveloped areas. It is concluded that spatial autocorrelation analysis is a good method to quantitatively analyze the spatial variation of marketing level of state-owned land supply in China. To grasp the spatial and temporal variations of the marketing level of state-owned land supply is also good to enhance running of the state-owned land market.

Spatial Analysis and Modelling of Wind Farm Site Suitability in Nasarawa State, North-Central Nigeria

There has been an increasing global and local interest in developing renewable, clean, and cheap energy towards achieving Goal number 7 of the Sustainable Development Goals (SDG). However, decisions involving suitable and sustainable locations for renewable energy projects remain an important task. This study employed Geographic Information System (GIS) and Multi-Criteria Decision Analysis (MCDA) to spatially analyze and model wind farm site suitability in Nasarawa State. The aim is to integrate the environmental, social, and economic aspects of decision-making for identifying sustainable wind farm sites. The study distinguished between two sets of decision criteria: decision constraints and decision factors. The former defined the exclusion zones while the latter were standardized based on fuzzy logic to depict varying degrees of suitability across the State. The MCDA applied the weighted linear combination method, with relative weights generated through pairwise comparisons of the analytic hierarchy process to analyze three policy scenarios: equal weights, environmental/social priority, and economic priority scenario. A combination of resulting composite maps from the constraints and the factors gave the final suitability maps. The resulting suitability index (SI) for the respective policy scenario describes the degrees of suitability: Ideal locations were denoted by one (1) and the not suitable locations by zero (0), with values in-between depicting varying degrees of wind farm site suitability. Based on the SI, priority locations indicating areas with good prospects, in addition to the most suitable parcels of land, were identified and delineated. The composite decision constraint revealed that wind farm projects would not be viable in more than half (57.58%) of the State. Wind speed was the major constraint and accounted for the exclusion of 46.25%, with a mean fuzzy membership value of 0.2008 indicating low suitability across the State. Also, the average acceptable wind farm location for the three-policy scenario was 33.33% of the entire study area. Lafia, Obi, Keana, Awe, Nasarawa-Eggon, Wamba and Kokona LGAs were the identified priority Local Government Areas (LGAs). However, only Lafia, Obi, and Nasarawa-Eggon were consistent with changes in the policy objectives. All the priority LGAs have one or more of the most suitable parcels within their administrative boundaries except for Wamba. Despite the severe limitations of wind speed, substantial parts of Nasarawa State still provide great development potentials for wind energy. The “most suitable” locations in Lafia, Nasarawa-Eggon, and Obi LGAs should have first consideration for the development of wind energy in the State.

基于Oracle Spatial的REST的API的设计与实现

采用了.net平台下的Windows Communication Foundation(WCF)技术,完成了基于Oracle Spatial的REST API的设计与实现,与传统Web Service的架构相比具有轻量级、高效率、灵活性和易用性、可扩展性和无状态性等优点[1],能够更好的为用户提供Oracle spatial相关功能的服务。

An Air Mass Based Approach to the Establishment of Spring Season Synoptic Characteristics in the Northeast United States

The Northeast United States spring is indicative of major meteorological and biological change though the seasonal boundaries are difficult to define and may even be changing with global climate warming. This research aims to obtain a synoptic meteorological definition of the spring season through an assessment of air mass frequency over the past 60 years. The validity of recent speculations that the onset and termination of spring have changed in recent decades with global change is also examined. The Spatial Synoptic Classification is utilized to define daily air masses over the region. Annual and seasonal baseline frequencies are identified and their differences are acquired to characterize the season. Seasonal frequency departures of the early and late segments of the period of record are calculated and examined for practical and statistical significance. The daily boundaries of early and late spring are also isolated and assessed across the period of record to identify important changes in the season’s initiation and termination through time. Results indicate that the Northeast spring season is dominated by dry air masses, mainly the Dry Moderate and Dry Polar types. Prior to 1975, more polar air masses are detected while after 1975 more moderate and tropical types are identified. Late spring is characterized by increased variability in all moist air mass frequencies. These findings indicate that, from a synoptic perspective, the season is dry through time but modern springs are also warmer than those of past decades and the initiation of the season is likely arriving earlier. The end of the season represents more variable day-to-day air mass conditions in modern times than detected in past decades.

Cross-sectional study and spatial distribution of schistosomiasis among children in Northeastern Nigeria

Objective: To determine schistosomiasis level and risk factors that exposed school-aged children to infection as well as to model schistosomiasis map in relation to altitude and rainfall in Gashaka Local Government Area, Taraba State, Nigeria.Methods: The study was conducted between January 2014 and June 2014. Urine and faecal samples were collected from 1 080 school-aged children and processed using the filtration and formol–ether concentration techniques, respectively.Results: Irrespective of the schistosomes species, a point prevalence of 10.18% was reported out of the 1 080 children examined. Males were significantly infected than their female counterparts(11.75% vs. 8.43%)(χ2= 4.86; P = 0.027), as well as children aged6–10(11.65%, 72/618) and 11–15 years(10.29%, 35/340) than the other age groups(χ2= 9.274; P = 0.026). No significant difference was observed in schistosomiasis between children whose parents were educated(11.11%, 57/513) and not educated(9.88%,53/536)(χ2= 1.342; P = 0.247) and those whose parents are farmers(9.74%, 53/544) and non-farmers(10.63%, 57/536)(χ~2= 0.787; P = 0.375). Proximity to water bodies(distance < 500 m)(odds ratio = 1.809, confidence interval = 1.057–3.094; P = 0.003 1)and fishing(odds ratio = 2.632, confidence interval = 1.397–4.958; P = 0.003) were the risk factors exposing children to infection. The spatial distribution pattern of schistosomiasis showed that the infection was significantly higher in Serti A(22.2%, 26/180) and Mayo-Selbe(21.1%, 38/180) than the other localities(χ~2= 92.99; P = 0.000).Conclusions: This study reported a moderate level of infection among school-aged children with proximity to water bodies and fishing as the main risk factors. The spatial distribution of schistosomiasis in the area will guide in efficient and effective control programmes at local level. It is recommended that continued efforts be made to scale-up distribution of praziquantel to high risk areas so as to curb the progression of the disease.

Forest Fires and Climate Correlation in Mexico State: A Report Based on MODIS

Forest fires are one of the most important threats for forests in the State of Mexico. Therefore, understanding their geographical patterns is a priority for the design of forest management strategies. We processed the records obtained with the MOD14A2 product (for thermal anomalies and fire) of MODIS sensor. Such scenes correspond to dry seasons (from March 15 to June 30) from 2000 to 2012 in the State of Mexico. We analyzed such records in a GIS environment to learn their spatial patterns and establish their geographical correlations as a first step to understand the causal agents of forest fires. As a result, forest fires in the State of Mexico showed a clustered spatial trend with a southwest tendency and a slight spatial relation with total winter precipitation and maximal temperature in summer.

An Algorithm for Idle-State Detection and Continuous Classifier Design in Motor-Imagery-Based BCI

Abstract-The development of asynchronous brain-computer interface （BCI） based on motor imagery （M1） poses the research in algorithms for detecting the nontask states （i.e., idle state） and the design of continuous classifiers that classify continuously incoming electroencephalogram （EEG） samples. An algorithm is proposed in this paper which integrates two two-class classifiers to detect idle state and utilizes a sliding window to achieve continuous outputs. The common spatial pattern （CSP） algorithm is used to extract features of EEG signals and the linear support vector machine （SVM） is utilized to serve as classifier. The algorithm is applied on dataset IVb of BCI competition Ⅲ, with a resulting mean square error of 0.66. The result indicates that the proposed algorithm is feasible in the first step of the development of asynchronous systems.

江南园林空间节奏量化分析研究——以留园为例

节奏虽作为音乐领域的惯用名词,但常被用于描述园林中的空间体验。旨在突破传统空间于文学层面的“节奏”评价,客观、理性地分析江南园林空间节奏的发展规律。借节奏在音乐领域的概念,对园林的空间节奏进行深入的解读和量化分析,以留园为空间样本,基于统计学和空间句法对游览状态的变化时间与造景密度进行图示分析。发现园林空间节奏的快慢感受与游观速度无关,而与运动状态的变化速率有关。最终根据所得数据结论提取留园中的空间节奏序列模式及空间原型,为空间节奏的设计方法提出实践的可能性方案。

A study on the spatial flow intensity of overseas travelers in tourist hotspots of China──taking Beijing as an example

Through practical sampling survey for the overseas travelers in the 12 tourist hotspot cities of China, the analytical results of database of the spatial changes for overseas travelers have been established with the help of the software Visual FoxPro. The New concepts such as transferring state, which can be used to study the spatial flow intensity of travelers. is first put forward By analyzing the statistical results, the spatial flow intensity of 12 tourist hotspot cities in China for overseas travelers has been probed At last, a practical research of spatial flow intensity for overseas tourists is carried out in Beijing──the of tourist hotspots of China

船舶流量智能交通检测系统设计

以避免船舶AIS数据内噪声对船舶流量检测干扰,准确、实时实现船舶流量智能交通检测,设计船舶流量智能交通检测系统。采集模块采集海上航线船舶AIS数据,使用逻辑分析模块内的船舶交通流状态空间模型,获取当前海上航线船舶交通流空间状态,卡尔曼滤波算法将上一个航线船舶交通流空间状态作为观测向量,同时抑制船舶交通流空间状态观测向量内干扰噪声,建立船舶流量智能交通检测模型,不断更新海上航线船舶流量空间状态转移矩阵,推理当前时刻船舶交通流量空间状态,得到船舶流量智能交通检测结果。实验表明,该方法具备较强的船舶AIS数据获取能力,可准确获得海上航线船舶流量状态,并有效检测不同时刻船舶流量,应用效果较好。

双循环背景下城市群的空间重构与规划应对——基于新国家空间理论

基于新国家空间理论,构建了“资本循环-空间建构-规划应对”的分析框架,审视由“外循环”向“双循环”转变过程中城市群的空间重构需求,提出相应的规划编制策略。研究发现:双循环新发展格局下,中国城市群在全球、国家和区域尺度均面临多重挑战。现阶段中国19个国家级城市群在经济循环中需担任不同的角色:成熟型城市群参与外循环,发展型城市群驱动内循环,培育型城市群组织微循环。为实现城市群空间重构,3种类型的城市群需有不同的国家空间工程构建逻辑和规划传导原则,以及国家空间策略部署途径和规划编制重点。本文的研究结果填补了空间规划服务于国家新发展格局的理论空白,从城市群角度为双循环战略提供重要理论和规划支撑。

美国科技创新水平时空格局演变与影响因素

在全球科技竞争愈演愈烈的今天,科技创新已成为国际竞争力的核心组成部分。在中美科技摩擦不断升级的背景下,深入研究美国的科技创新水平时空格局演变对于把握世界科技创新的发展水平和特点,以及促进中国科技创新实力的提升具有重要意义。本研究以美国专利发表量等数据为基础,分析2000-2022年美国科技创新的演化规律及影响因素。发现美国科技创新水平持续增长,尽管受到经济危机、政策变化等影响,但整体稳健发展。同时,东西海岸地区创新活动集中,中部地区科技创新水平相对较低。此外,美国科技创新的空间格局逐渐向西移动,集聚度增强。这些发现为深化中国科技创新中心布局和发展战略提供了重要启示。中国应重视区域科技创新的集聚特征,推动创新带动效应;加强科技创新政策法规完善,吸引社会资本投入科技创新;同时,因地制宜培育科技创新高地,发挥科研机构集聚区优势,促进科技实力提升。

基于STL-Bayesian时空模型的分布式光伏系统异常检测

分布式光伏发电系统一般不配备多种类的传感器和监测设备,反映设备运行状态且可用于异常检测的数据有限。提出了基于STL-Bayesian时空模型的光伏异常状态检测方法,利用气象在时空上的传递性,挖掘光伏发电出力的关联性进而完成异常检测。首先,用季节性分解(seasonal and trend decomposition using loess,STL)将光伏发电有功功率时序数据分解为3个分量;然后,研究不同长度数据输入对分解结果的影响和区域内分量的时空分布特性;接着,通过构建贝叶斯模型分别对趋势分量和剩余分量做短期和超短期空间插值,得到区域内光伏出力;最后,计算真实值与回归值的推土机距离(earth move's distance,EMD)用于检测异常状态。算例分析表明,所提模型在分布式光伏场景检测可逆异常和不可逆异常状态均有较高准确率。

中国基本公共服务发展水平的统计测度与时空效应

基本公共服务均等化是实现共同富裕的着力点,对基本公共服务发展水平进行精准测度,把握好各地区基本公共服务发展的差异性,对扎实推进共同富裕具有重要意义。依据“七有”“两保障”标准构建基本公共服务发展水平评价指标体系,采用熵权法测算2011—2020年各省份基本公共服务发展指数的时空变化。继而利用空间Kernel密度估计方法刻画空间影响下各地区发展水平的分布形态和演进规律。最后通过空间Markov转移概率矩阵进一步量化空间影响下的状态转移概率和内部动态性。研究发现:2011—2019年各省份基本公共服务发展水平稳步提升,中西部地区增速高于东部地区。2011—2020年各省份基本公共服务发展水平主要集中在较低水平,总体上呈现右移趋势;东部地区聚集趋势最弱,两极分化态势较为严重;中部地区极化特征不明显,但内部结构的稳定性较差;西部地区的基本公共服务发展水平存在下降的风险。空间因素对各地区发展水平存在显著影响,不同水平的地区具有俱乐部收敛特征。各省份基本公共服务发展水平主要向中低水平和中高水平转移,低水平和高水平地区的状态转移流动性最差;高水平地区影响下各地区均无状态转移,固化现象凸显。因此,当前阶段中国在推进共同富裕的进程中需要扩大东西联动交流,提高中西部公共服务的持续造血能力;增强区域协作机制,实施区域协调发展;关注虹吸效应,切实弱化两极分化态势。

空间财政理论:缘起、分析框架与启示建议

空间财政作为观察财政的新视角,是财政在国家治理结构中空间维度上的反映。以空间视角探究财政治理方式,对于完善拥有巨大人口规模、广袤地理空间及发展不平衡不充分的发展中大国具有重要意义。当前,从空间维度开展财政理论研究,已成为国内外共识,但对空间财政的理解认识各异,尚未能形成统一定义,理论基础也相对薄弱,在国家治理层面探究空间财政的相关研究亦不丰富。为此,本文从空间财政的概念界定出发,探讨了国家治理视角下空间财政的内涵,尝试构建“效率—公平—风险”维度的分析框架,提出了空间财政发展的相关启示建议,以期为空间视角下推进财政理论研究、财政政策研究和财政改革实践提供有益参考。

基于深度学习的矿用救援机器人自动避障方法

救援机器人自动避障性能存在不足,在实际中救援成功率和避障平滑系数较低,无法达到预期的避障效果,为此,提出基于深度学习的矿用救援机器人自动避障方法。首先,利用电子罗盘和超声波传感器感知救援机器人与障碍物的方位角和距离,搭建救援机器人空间状态;然后,建立具有三层卷积层和两层全连接层结构的深度学习网络模型,并搭建用于深度学习网络模型训练的救援机器人避障动作集合;最后,通过深度学习网络模型训练救援机器人的空间状态信息,提取救援机器人移动的空间特征,自动生成避障决策。实践证明,应用该设计方法后,救援机器人避障成功率在95%以上,平滑系数在0.85以上,具有良好的应用前景。