不同GPS网网形结构对控制点点位精度的影响

通过实际测量工作中遇到的不同GPS网网形结构,通过平差计算的结果,来阐述几种GPS网形式 对点位精度的影响。     

GPS网形结构对精度影响的探讨

对GPS网采用了全面边连式结构、点连式结构和导线网等3种不同网形进行平差分析,其结果是:全面边连式GPS网形结构强,点位精度高,适用于高精度工程控制网.点连式GPS网网形结构的点位精度与全面边连式网的精度相当,但点连式GPS网可大大减少野外观测和计算工作量.在满足地震勘探精度要求的情况下,优化GPS网的网形设计,可减少工作量,提高生产进度.     

巷道贯通测量中GPS和常规导线测量成果的可靠性互检

为保证矿井下轨道巷顺利贯通,分别在地面布设了GPSD级近井网和四等光电导线,使用两种成果对地面控制网成果作可靠性和精度互检,消除了GPS成果转化为1954坐标系统时受椭球定位、定向不明确,相对精度低、分区分级平差、点位建立时间长,点位可能产生较大位移等不利因素影响。互检结果对采用GPS测量方法和普通光电导线测量建立控制网的矿山企业进行大型巷道贯通测量时,具有重要的可供借鉴价值。     

GPS控制网优化设计思路及组网方案优选

详细分析了GPS网优化设计思路,结合实例,设计了5种GSP组网方案,通过进行点位平差分析,对不同方案的点位精度进行了对比分析,最终确定了最优组网方案,对于提高GSP组网设计效率以及GSP网精度具有一定的借鉴意义。     

边角自由设站极坐标法在基坑变形监测中的应用研究

针对由设站极坐标法进行基坑变形监测时的精度保证问题,文中根据间接平差原理和误差传播规律重点对点位构成的网形、角度和距离测量精度等进行公式推导分析,对提高监测点点位精度的方法进行了探讨,给出了一些提高测量精度的措施。     

GPS独立控制网的平差计算方法分析

对姑山矿区控制测量中GPS独立控制网的平差计算方法进行论述,并对平差结果进行检验,分析其精度和适用性,说明如何利用现有平差软件PowerADJ计算GPS控制网的网点坐标,以满足矿山测量的精度要求。     

工程GPS网的精度与施工复测

文中利用实际工程的GPS测量资料,统计了工程GPS网的实测精度,提出了用WGS-84系无约束平差的精度信息作为GPS控制网的精度要求指标;采用WGS-84系无约束平差结果,以空间距离、角度比较法评价工程控制网施工复测的控制点稳定性,旨在为工程项目进行测量设计提供经验参考数据,为修订GPS规范提供一些有价值的参考资料。     

某煤田地质勘探区大比例尺测图GPS测量技术

为了满足某煤田地质勘探区大比例尺测图和工程定位的需要,讨论了在煤田地质勘探区控制测量的精度需求,根据此要求用GPS定位方法建立了控制网.测量平差和精度评定表明GPS定位技术是建立煤田地质详查区控制网的最优方法之一,同时指出了GPS测量应注意的问题,得出了有益的结论.     

关于矿区GPS网基准点选取的试验研究

根据矿区GPS网的特点,通过具体试验,对矿区GPS网约束平差结果进行分析、比较,得出了作为起算数据的基准点,其数量、位置和稳定性对矿区GPS网约束平差精度的影响规律,以及如何选择可靠的基准点作为矿区GPS网的位置基准,使得矿区GPS网平差结果满足生产要求具有重要理论和实际意义.     

临淄区四等GPS网的布网特点及精度分析

介绍了临淄区GPS网的布设方案、数据采集、基线向量检核及平差计算等,分析了该网的网形特点及平面精度.经该区四等GPS布网及施测的工程实践,认为:对于建立一般工程或局部区域控制网,宜进行一次性全面布网,这样不仅可以保证点位精度,而且可以较大地提高工作效率.     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586