ZY1-02DAHSI影像归一化阴影植被指数NSVI的波段选择及其构建

高光谱影像具有连续的地物光谱信息,在阴影检测方面具有巨大的潜力,而波段冗余度高需进行波段优选。归一化阴影植被指数(NSVI)能够扩大光谱差异,在高光谱影像中应用NSVI将更有效地识别阴影。资源一号02D卫星是我国首颗自主研发并成功运行的高光谱业务卫星,数据信噪比大、覆盖能力强,对该高光谱影像进行准确的阴影检测具有重要意义。以ZY1-02DAHSI影像为试验数据,提取并分析明亮区植被、阴影区植被及水体的光谱反射率;结合竞争自适应重加权采样(CARS)和连续投影算法(SPA)筛选能够有效区分典型地物的主要波段,综合考虑算法的特性进一步选出特征波段构建NSVI;通过步长法确定最佳阈值对影像进行分类,从像元值分布情况、分类精度和光谱增强效果等对比出构建NSVI的最佳波段,并结合不同的阴影指数、波段和影像进行综合评价,验证该方法的意义及普适性。结果表明:波段32和波段73是构建NSVI的最佳波段,分别对应红光波段和近红外波段;不同波段构建的NSVI分类精度均高于90%,由最佳波段构建的NSVI分类精度为94.33%,Kappa系数为0.8328,分类效果最优;NSVI能够增强典型地物间的光谱差异并缓解归一化植被指数的“易饱和”现象,在该影像中因水体累积产生的小波峰有助于提取水体;在ZY1-02DAHSI影像中NSVI的分类效果优于归一化阴影指数和阴影指数,于另一景影像的分类精度也达到93.55%,Kappa系数为0.8167。由算法筛选出的波段具有一定的代表性,最佳波段构建的NSVI在ZY1-02DAHSI影像中具有较好的阴影检测能力,对高光谱影像阴影检测及构建植被指数具有一定的借鉴和参考意义。

生产性服务业与制造业融合发展的区域比较研究

发展服务型制造、推动生产性服务和制造业融合是供给侧结构性改革的战略选择。从京津沪渝四个直辖市和粤鲁苏浙四个较为发达省份综合来看,制造业与生产性服务业之间存在着一定的关联效应和协同发展趋势,同时存在省市之间、行业之间的分异特征,且生产性服务业整体规模还与工业发展需求不相适应,表现在规模上其对工业的前向关联效应较弱。当然,近期呈现出生产性服务业在增长速度上与工业增速高度相关的发展态势。为更好实现生产性服务业与制造业融合协同发展,我国在服务业供给侧结构性改革进程中要转变制造业和服务业传统“二分法”思维,确立生产性服务业优先发展地位,着力推进研发性服务业高质量发展、坚守健康底线推进环保等高增长领域先行发展和坚持规模化导向推进商务服务业发展。

基于可视化图谱分析我国高校体育课程改革现状及未来展望

运用Citespace 6.2R2软件以及知网文献可视化功能对中国知网数据库中研究我国高校体育课程改革的300篇核心期刊论文进行可视化分析,力求探究我国高校体育课程改革的现状、趋势及当前热点。研究表明:我国高校体育课程改革的期刊发文量整体显现出上升的趋势;作者之间合作以及团体之间的合作较少,较为分散;研究对象不断扩展,我国高校体育课程交叉融合愈加紧密;以“体育教育”“课程思政”“高校”“教学”“高校体育”为代表的研究主题是当前高校体育课程改革领域的研究热点。结论:高校体育课程有助于推动学校体育事业的发展;通过改革,可以有效弥补现有体育课程的不足,提升教育质量和教学效果;高校体育课程改革不仅对学生个体具有积极影响,也对整个社会和国家的发展具有深远影响,值得高度重视和支持。展望:未来高校体育课程改革应该着重强化体育教育的全面性、提高教学质量、融合思想政治教育。通过这些方面的努力,可以进一步提升高校体育课程的效果和学生的综合素质,培养全面发展的人才。

Development of Cloud Movement Prediction Method for Solar Photovoltaic System

Variability of power generation due to the prevalence of cloud cover over solar photovoltaics(PV)power plants is a challenge faced by grid operators and independent system operators(ISOs)in the integration of solar energy into the grid.Solar forecasts generated through ground⁃based sky imaging systems are useful for short⁃term cloud motion predictions.However,the cost of sky imaging systems currently available in industries is relatively high.Hence,a ground⁃based camera system utilizing a simple webcam is proposed in this study.The proposed method can produce predictions with high levels of accuracy.Forecasts were generated through video analysis using MATLAB for the computation of cloud motion predictions.The image processing involved in the implementation of the proposed system is based on the detection of cloud regions in the form of a cluster of white pixels within individual frames and tracking their motion through comparison of subsequent frames.This study describes the techniques and processes used in the development of the proposed method,along with the evaluation of performance through analysis of the results.The predictions were carried out over multiple time horizons.The time horizons selected include 5,10,15,20,25,and 30 s.The overall results computed showed promising accuracy levels above 94.60%,which makes it adequate for generating reliable forecasts.

Generation of OAM Waves and Analysis of Mode Purity for 5G Sub-6 GHz Applications

This article presents the generation of Orbital AngularMomentum(OAM)vortex waves with mode 1 using Uniform Circular Array(UCA)antenna.Two different designs,namely,UCA-1(4-element array antenna)and UCA-2(8-element array antenna),were designed and fabricated using FR-4 substrate to generate OAM mode 1 at 3.5 GHz(5G mid-band).The proposed antenna arrays comprised rectangular microstrip patch elements with inset fed technique.The elements were excited by a carefully designed feeding phase shift network to provide similar output energy at output ports with desired phase shift value.The generated OAM waves were confirmed by measuring the null in the bore sight of their 2D radiation patterns,simulated phase distribution and intensity distribution.The measurement results agree well with the simulation results.Moreover,a detailed mode purity analysis of the generated OAM waves was carried out considering different factors.The investigation found that the greater the number of elements,the higher the purity of the generated OAM wave.Compared with other previous works,the proposed antenna design of this paper is very simple to design and fabricate.In addition,the proposed antennas are compact in design even at lower frequency band with very wide bandwidth to meet the requirements of 5G mid-band applications.

互联网流量分布趋势研究

根据今年2月25日CNNIC发布的数据,截至2021年12月,我国互联网网民规模达10.32亿人,互联网普及率达73.0%,人均每周上网时长为28.5小时。面对如此高的普及率和上网时长,人们很自然地想到:网民普及率会不会继续提高,上网时长会不会继续增长,中国的互联网能不能承担这么大的流量?本文通过对互联网流量的参与主体、影响因素进行分析和论述,尝试厘清一些内在的规律,解答上述问题并为后续策略的制定提供参考。

Interleukin-33 exerts pleiotropic immunoregulatory effects in response to Plasmodium berghei ANKA(PbA)infection in mice

Objective:To determine the involvement and the modulatory effects of IL-33 during Plasmodium berghei ANKA(PbA)infection.Methods:PbA infection in male ICR mice was utilized as a model of malaria.Systemically circulating IL-33 levels were determined in blood plasma by enzyme-linked immunosorbent assay(ELISA).After 24 hours post-inoculation of PbA,recombinant IL-33 and ST2,and antibodies against IL-33 and IgG treatments were administered daily for 3 days.Tissue expression and localization of IL-33 were assessed in organs generally affected by malaria via immunohistochemistry.Moreover,histopathological examination was performed to assess the effects of the treatments.Results:The levels of systemic IL-33 were elevated at the critical phase of PbA infection.Likewise,immunohistochemical analysis revealed a significant upregulation of IL-33 expression at the critical phase in the brain,lungs,and spleen of PbA-infected mice as compared to healthy controls.Treatment with IL-33 protected against experimental cerebral malaria development and reduced pathological features in the brain and lungs of the PbA-infected mice.Conclusions:A potential critical role and involvement of IL-33 in PbA infection may hint at the resolution of immunopathological sequelae associated with malaria.

算力调度关键要素及路径分析

我国算力规模已在全球排名第二,近五年平均增速超过30%,高速增长的背后需要考虑如何满足千行百业的需求。本文从算力及算力应用场景分类入手,针对不同场景分析总结了影响算力调度的关键要素及策略,进一步对不同应用可采取的调度路径进行了分析研判,旨在提供一个有效使用算力的思路。

基于GIS的农业生产基地空间数据库的设计与实现——以广西大容山农业基地为例

将空间数据库技术应用于农业生产与管理,是对农业数据空间化管理和可视化表达的一种尝试。文章以广西大容山农业生产基地为研究对象,将空间数据库技术应用于农业数据管理,探讨了基于ARCSDE的农业数据库的设计与建立,从数据结构的角度出发,分析不同类型数据分层存储与管理模式。农业空间数据库的建立实现了农业空间数据和农业生产数据的融合,提高了农业生产管理的效率,同时实现了生产资料的统一调度和人力成本的节约高效利用,对农业生产管理具有积极的促进意义。

Adsorption Isotherm Study of Activated Fruit Peels for Copper Removal

Heavy metal polluted water threatens the integrity of ecosystem.The use of agricultural waste as adsorbent becomes popular due to its biodegradability and availability.However,limited research works has been done to process agricultural waste for heavy metal adsorption purpose.The objective of this study is to propose a new approach to treat banana peel using ZnCl_(2) prior to alkali and acid treatment and explore the potential of dragon fruit peels as the adsorbent for Cu^(2+)adsorption.Seven adsorption isotherm was adopted to identify the adsorption mechanism and four statistical parameters were calculated for model verification purpose.The experiment was conducted by dispersing ZnCl_(2) treated and untreated adsorbents into Cu^(2+) solution.Results showed that ZnCl_(2) treated adsorbents performed better in terms of Cu^(2+) removal compared with untreated adsorbents due to higher surface area for Cu^(2+) adsorption.The treated banana peel(Act.-B)performed approximately 30%better than the treated dragon fruit peel(Act.-D)due to the presence of hydroxyl and carboxyl groups.The equilibrium adsorptive capacity of Act.-B was 1872.8 mg Cu^(2+)/g and the experimental data fitted Freundlich isotherm well with R^(2)=0.9978,0.0161 of residual sum of error(SSE),0.0068 of χ^(2),and 0.0567 of root mean square error(RMSE)values.This suggests non⁃linear adsorption and multilayer adsorption on heterogenous surfaces.Thus,it is recommended to further improve the surface properties of Act.-B by steam pyrolysis and surface modification.

Kinetic Study for Adsorption of Heavy Metals on Zeolite

Heavy metals⁃polluted water has negative impact on the ecosystem.In Malaysia,minimum discharge limit for Cu^(2+)and Zn^(2+)are 1 mg/L and 2 mg/L,respectively.Zeolite is a highly porous adsorbent and its performance is affected by various factors,including contact time and pH.Thus,the objective of this study is to identify an ideal operating condition to treat Cu^(2+)and Zn^(2+)solutions up to the allowable discharge limit,by considering the pH and contact time factors.Six kinetic models were studied to identify the adsorption mechanism of the heavy metal removal process.Single solute batch adsorption experiment was conducted within pH 3-11 from 30 to 150 min.Results showed that hydration enthalpy(ΔHhyd)governed the selectivity of heavy metals,where a maximum of 90.87%Zn^(2+)(ΔH_(hyd)=-1955 kJ/mol)and 82.15%Cu^(2+)(ΔH_(hyd)=-2010 kJ/mol)removals were found at pH≥7.Without pH adjustment,selectivity towards Cu^(2+)was higher compared with Zn^(2+)due to the size of hydration radii,where Cu^(2+)is 0.11Åsmaller than Zn^(2+).By considering both pH and contact time factors,this study shows that by adjusting the pH of Zn^(2+)solutions to a minimum pH value of 7,the contact time required to achieve maximum Zn^(2+)removal rate was 90%,which can be achieved within 60 min.Meanwhile,zeolite performed better in Cu^(2+)removal without any pH adjustment where a maximum of 94%was achieved at 120 min.Final concentration of 0.523 mg/L Cu^(2+)and 0.981 mg/L Zn^(2+)were obtained in this study.Kinetic study showed that Ritchie’s equation predicted Cu^(2+)adsorption the best,while Zn^(2+)adsorption could be represented by Elovich model.This suggested that the adsorption on the activate site governed Cu^(2+)and Zn^(2+)removal process.Hence,future work should focus on modifying zeolite surface to improve the adsorptive performance.

Comparative Study on Microstructures of Zincalume Steel(G550)Welded Joint Between Metal Inert Gas and Laser Beam Welding

Zincalume steel(G550)is commonly used in various construction fields because of its high corrosion resistance and good mechanical properties.In recent years,a number of steel companies have massively produced zincalume steel(G550)with large volumes of waste.For the reduction of massive industrial wastes,the zincalume steel(G550)was welded in the lap joint configuration using different welding parameters in the metal inert gas(MIG)welding and laser beam welding(LBW)process in this study.The MIG welding and LBW are more welcomed welding methods due to their high efficiency and low cost.However,they are different as the LBW offers welding speed three to five times faster than MIG welding,while LBW’s heat transfer to workpieces is much less than MIG welding,which can avoid some distortions.The microstructure of zincalume steel(G550)was investigated using scanning electron microscopy(SEM)and the microstructure characterizations of welded specimens were analyzed.The experiment found the columnar dendrites extended under the heat flow direction during the MIG welding and LBW process.Thus,the columnar grains were formed in between the equiaxed zone and fusion zone(FZ)at high heat input and slow cooling rate.Moreover,the grain size of FZ was comparatively smaller than heat affected zone(HAZ)and base metal(BM).

A Qualitative Study of Early Childhood Education Using NVivo11

Based on the grounded theory,with NVivo11,from the perspectives of teachers,parents,kindergarten administrators,students who major in preschool education,children and policies,the author did the qualitative research and analysis on the texts,videos,radios,and pictures that reflected children’s lives,games,and studies.The result showed happiness,respect to children,love,health,the growth and development of life,habit formation,intelligence enlightenment,and the favorable environment can reflect the essential characteristics of preschool education.However,interest classes and the tendency to make a kindergarten as an elementary school are abnormal in preschool education and deviate from the essence of preschool education and should be corrected.

Palmitic Acid-Lauric Acid/Expanded Graphite as Form-Stable Composite Phase Change Material for Low-Temperature Energy Storage Applications

Low thermal conductivity of binary fatty acid mixture of palmitic and lauric acids(PA-LA)within the value range of 0.15-0.17 W/(m·K)restricts its wide utilization as thermal energy storage material in the active regime of solar heating applications at low operating temperatures.Nevertheless,this mixture as phase change material(PCM)has a suitable phase-change temperature and heat of 36℃and 176.3 J/g,respectively.Hence,the objective of this study is to formulate a novel form-stable composite PCM with the PA-LA mixture and expanded graphite(EG)as a thermal enhancer.PA-LA eutectic mixture with varied concentrations of EG was prepared and characterized.The thermal conductivity of PA-LA/EG increased gradually with the mass of EG.Optimum thermal properties were observed in PA-LA/(5%EG)composite,where its melting(T_(m)),freezing temperature(T_(t)),latent melting heat and thermal conductivity was 35.53℃,34.84℃,174 J/g,and 1.19 W/(m·K),respectively.Also,the composite PCM is characterized by good chemical-thermal stability and thermal reliability for long-term usage.In conclusion,it can be utilized as a prospective form-stable PCM for thermal energy storage in solar heating systems,overheat treatment systems,and other thermal storage applications at low operating temperatures.

Optimization of Photovoltaic Reflector System for Indoor Energy Harvesting

This study proposes a solution for optimizing the distance between a solar module and reflector for an indoor energy harvesting system.It is a process in which energy(ambient light)is captured and converted directly into electricity.Inside a building,this energy could be used to supply power to wide range of portable equipment or offset other electrical energy usage and associated costs.The proposed reflector element was designed and tested in a real indoor environment to confirm its effectiveness.A distance⁃optimization method for the placement of a polycrystalline photovoltaic(PV)module and a mirror was described,and the performance characteristics of the system were investigated qualitatively through visual observation and quantitatively through measuring voltage and ampere values.The solar PV system with a reflector element displayed a 10%increase in voltage when compared with that without.As the distance between PV module and the reflector increased,the voltage and ampere reading decreased,thus the distance was optimized to gain maximum readings.Various studies employing reflectors have also showed increases in voltage readings with different designs,suggesting that reflectors are economically viable optical elements that can boost the voltage output of a PV module.In practice,the distance⁃optimized PV module can be placed in buildings with extended indoor lighting duration away from disrupting building activity.

Long-Term Electricity Demand Forecasting for Malaysia Using Artificial Neural Networks in the Presence of Input and Model Uncertainties

Electricity demand is also known as load in electric power system.This article presents a Long-Term Load Forecasting(LTLF)approach for Malaysia.An Artificial Neural Network(ANN)of 5-layer Multi-Layered Perceptron(MLP)structure has been designed and tested for this purpose.Uncertainties of input variables and ANN model were introduced to obtain the prediction for years 2022 to 2030.Pearson correlation was used to examine the input variables for model construction.The analysis indicates that Primary Energy Supply(PES),population,Gross Domestic Product(GDP)and temperature are strongly correlated.The forecast results by the proposed method(henceforth referred to as UQ-SNN)were compared with the results obtained by a conventional Seasonal Auto-Regressive Integrated Moving Average(SARIMA)model.The R^(2)scores for UQ-SNN and SARIMA are 0.9994 and 0.9787,respectively,indicating that UQ-SNN is more accurate in capturing the non-linearity and the underlying relationships between the input and output variables.The proposed method can be easily extended to include other input variables to increase the model complexity and is suitable for LTLF.With the available input data,UQ-SNN predicts Malaysia will consume 207.22 TWh of electricity,with standard deviation(SD)of 6.10 TWh by 2030.

A Novel Power Curve Prediction Method for Horizontal-Axis Wind Turbines Using Artificial Neural Networks

Accurate prediction of wind turbine power curve is essential for wind farm planning as it influences the expected power production.Existing methods require detailed wind turbine geometry for performance evaluation,which most of the time unattainable and impractical in early stage of wind farm planning.While significant amount of work has been done on fitting of wind turbine power curve using parametric and non-parametric models,little to no attention has been paid for power curve modelling that relates the wind turbine design information.This paper presents a novel method that employs artificial neural network to learn the underlying relationships between 6 turbine design parameters and its power curve.A total of 198 existing pitch-controlled and active stall-controlled horizontal-axis wind turbines have been used for model training and validation.The results showed that the method is reliable and reasonably accurate,with average R^(2)score of 0.9966.

Reliability Based Multi-Objective Thermodynamic Cycle Optimisation of Turbofan Engines Using Luus-Jaakola Algorithm

Aircraft engine design is a complicated process,as it involves huge number of components.The design process begins with parametric cycle analysis.It is crucial to determine the optimum values of the cycle parameters that would give a robust design in the early phase of engine development,to shorten the design cycle for cost saving and man-hour reduction.To obtain a robust solution,optimisation program is often being executed more than once,especially in Reliability Based Design Optimisations(RBDO)with Monte-Carlo Simulation(MCS)scheme for complex systems which require thousands to millions of optimisation loops to be executed.This paper presents a fast heuristic technique to optimise the thermodynamic cycle of two-spool separated flow turbofan engines based on energy and probability of failure criteria based on Luus-Jaakola algorithm(LJ).A computer program called Turbo Jet Engine Optimiser v2.0(TJEO-2.0)has been developed to perform the optimisation calculation.The program is made up of inner and outer loops,where LJ is used in the outer loop to determine the design variables while parametric cycle analysis of the engine is done in the inner loop to determine the engine performance.Latin-Hypercube-Sampling(LHS)technique is used to sample the design and model variations for uncertainty analysis.The results show that optimisation without reliability criteria may lead to high probability of failure of more than 11%on average.The thrust obtained with uncertainty quantification was about 25%higher than the one without uncertainty quantification,at the expense of less than 3%of fuel consumption.The proposed algorithm can solve the turbofan RBDO problem within 3 min.

Preliminary Investigation of Copper Joints Soldered with Sn58Bi

In recent years,intensive studies have been carried out to find an alternative for Tin(Sn)⁃Lead(Pb)solder alloys with increasing demand over lower temperature solder alloys in current electronic packaging industry.High temperature operational solder alloys seem to produce drawback to other components on the printed circuit board(PCB).Low melting temperature Sn58Bi substrate as a potential replacement was investigated in this paper based on the melting properties,wettability,and shear strength.The Sn58Bi was soldered at a temperature below 200℃on the Cu substrate,and the shear strength and contact angle were calculated.A peak temperature(melting temperature,T_(M))of 144.83℃was identified.Single lap joint method was performed at a strain rate of 0.1 mm/min and an average shear strength of 23.4 MPa was found from three samples.The contact angle(wettability)was calculated to study the solder joint behaviour at reflow temperature of 170℃.The contact angle of the Sn58Bi was found to be 32.4°and considered to be desired value since the angle is less than 50°.The low temperature soldering provides a preliminary result to allow further application on the real PCB.

大地的守护

1.外景山脚下日一个老板模样的人蛮横地说:这片矿是我先发现的,只要我在这一天,你们就休想收走它。乡政府的工作人员解释道:根据规定,矿产资源属于国家所有。老板:我找人到处勘察矿地,好不容易才找到这里,凭什么你们说收走就收走?