数字吴川GPS首级控制网建立及精度分析

数字城市的建设方兴未艾,控制网的布设作为数字城市建设中的一个普遍现象,历来为建设者所重视。该文以数字吴川GPS首级控制网建设为例,详细介绍了数字吴川GPS首级控制网技术设计、外业观测、基线解算、网平差及精度分析和可靠性检验的整个过程,包括外业观测和内业解算的技术要求及数据解算的过程,并对已知数据的合理性和GPS控制网成果的正确性进行了分析。     

新发展阶段算力中心发展机遇和趋势探究

算力中心是数字经济的重要引擎,是国家核心竞争力的重要体现。本研究概述介绍了算力中心及其产业链,从政策规划、科技创新、数字经济、人工智能大模型4个角度分析了我国算力中心的发展机遇,指出了算力中心呈现出芯片多元化、软硬协同化、算网融合化、云边一体化、服务普惠化、设施低碳化6个发展趋势,并从政策、技术、产业、标准4个方面提出了我国算力中心高质量发展的对策建议,为我国算力中心建设实践提供了参考依据。     

临沂DMC航片生成正射影像的探讨

通过DMC影像资料分析了利用全数字摄影测量系统进行数字正射影像图的生产作业流程和实现技术线路,论述了外业及空三解算所需要的技术要求,说明了利用DMC影像进行大比例尺正射影像生产的可行性．最后指出了一些在实际生产过程中应注意的问题．     

美国战略计算计划的协调管理机制、实施特点及启示

随着信息技术的快速发展和数据量的暴增，算力成为数字时代重要的新型生产力。2016年以来，随着技术发展和需求的变化，美国重新制定了战略计算计划并更新了两个版本。文章分析了美国战略计算计划主要内容、协调管理机制及其“全政府”“举国”特点，结合我国算力发展中存在的主要问题，探讨了对我国算力发展的启示，包括制定算力研发战略、加强中央层面协调管理、培育先进计算产业、建立多种公私合作组织以凝聚各方力量等。     

计算机VR技术在数字媒体系统设计研究

计算机VR技术是利用电脑强大算力，以二进制创建虚拟仿真系统，让人意识进入其中，从而实现模拟现实的目的。目前VR技术在数字媒体系统中应用，主要解决将二维动态信息转换为三维信息，并在此过程中为用户提供加强感官体验，使用户有极强的沉浸感。目前VR技术结合了计算机图形学人机接口技术、多媒体技术、传感技术以及网络技术等。本文主要对计算机VR技术介绍，并阐述了数字媒体系统发展现状，针对VR技术对数字媒体系统的影响，阐明了两者的具体应用。     

边坡地质工程空间信息查询与量算方法探讨

随着科学计算可视化技术和地质信息计算机模拟技术的快速发展,工程地质可视化的需求也日益迫切。数字地质编录信息系统,以摄影测量理论为基础,综合运用近景数字影像和数字图像处理等技术,实现了工程地质编录数据的采集、处理、管理、分析和成果输出一体化,提高了专业信息化和生产力水平。通过对现有工程三维建模软件的不足,以边坡地质工程开挖体为研究对象,在数字地质编录系统生成的空间数据的基础上,对边坡地质工程空间信息查询和量算方法进行研究。     

中国算力的研究热点及趋势分析基于CiteSpace的文献计量分析

算力是数字经济时代关键的生产力,对于经济和社会的各个领域都具有深远的影响。研究以2011~2023年中国知网上刊发的4554篇算力相关论文为样本,借助CiteSpace进行时空分布、研究热点、研究前沿等方面的文献计量分析。算力研究正处于高速发展时期,研究热点集中于人工智能、区块链、算力网络、数字经济、算力基础设施等方面。算力研究领域创新迭代速度加快,研究主题和内容愈加丰富,算力网络建设、算力赋能各行业数字化转型等方面是未来的研究前沿。依据研究结论,建议丰富已有的研究方法,加强合作研究,关注国际算力研究前沿,形成中国独特的算力研究体系。     

基于BIM+数字孪生的高边坡施工检算动态反馈方法

为有效进行高边坡施工过程中不利工况的施工检算及动态反馈,以二次开发为依托,提出了基于参数化BIM模型及有限元方法快速进行高边坡不同工况稳定性检算的整套方案,并通过实际工程案例进行验证。首先,采用Revit二次开发技术实现不利工况高精度正向反馈至BIM模型;其次,将该BIM模型导入Abaqus中进行快速检算,基于Abaqus二次开发将有限元计算结果的自定义结构化输出;最后,采用Mesh重构方法将快速检算的结果向BIM环境反馈。结果表明：所提方案实现了数字孪生体与施工现场之间的同步关联,并且实现了数值计算结果与BIM环境互通。可见,BIM技术通过开发后可真实高效反映施工情况,并作为中间枢纽实现施工检算与成果管理,可为相关施工检算及BIM应用提供新思路。     

滑模观测器及其在无机械传感器永磁同步电机驱动系统的应用

为了取消永磁同步电机调速系统的机械传感器，电机转子的速度和位置通过测量定子电流和电压来估计，估计算法采用滑模观测器。采用逐段线性化处理技术，提出了一种滑模观测器在非线性系统中的新设计方法。根据这一方法，给出了用于永磁同步电机状态估计的具体算法。此算法简单，易于用数字计算机实现无机械传感器交流调速。通过数字仿真和实验测试，验证了所提算法的可行性。     

想想 做做

正一、读写算下面算式中,相同的汉字代表相同的数字,不同的汉字代表不同的数字。当"读""写""算"三个字各代表什么数字时,下面的算式成立?二、移火柴移动一根火柴棒,使下面的等式成立。三、插彩旗为庆祝三八妇女节,杨公小学在校门口插了12面红旗,他们还要在两面红旗之间     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has