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大尺寸计量技术在飞艇测量中的应用
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作者 王勤俭 阳志勇 +2 位作者 管鹏举 吴平 丁艳萍 《无线互联科技》 2017年第18期131-133,共3页
文章首先介绍大尺寸计量定义、大尺寸计量技术及测量仪器发展情况;然后针对湖南航天有限责任公司某大型飞艇囊体外形结构尺寸测量需求,分析一种基于3D摄影测量装置的大尺寸计量技术,并简要阐述了校准方法。
关键词 尺寸计量 3D摄影 飞艇测量 校准
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尺寸计量正在发生变化
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作者 沈福金 《世界制造技术与装备市场》 2000年第4期45-45,共1页
现在,越来越多的制造商认识到,提供工程零件的设计和制造之间的尺寸计量是不可缺少的环节。目前制造技术中的明显趋势将会继续很好的把尺寸计量的发展推入下一个世纪,以满足各工业部门的不同需要。 举例来说,从设计到制成各种零件的功... 现在,越来越多的制造商认识到,提供工程零件的设计和制造之间的尺寸计量是不可缺少的环节。目前制造技术中的明显趋势将会继续很好的把尺寸计量的发展推入下一个世纪,以满足各工业部门的不同需要。 举例来说,从设计到制成各种零件的功能性不断增加,因此零件尺寸的技术要求和公差更加复杂。结果,技术要求和公差的说明变得很重要,而且生产现场有许多不确定的未知因素。最终,制造公差变得越来越严格,把所需要的测量基准的精度放在更高的要求上,以满足制造过程。 展开更多
关键词 尺寸计量 计量仪器 测量基准 测量方法
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大尺寸计量中双光梳绝对测距方法的研究进展 被引量:3
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作者 刘洋 李建双 +3 位作者 赫明钊 曹士英 缪东晶 谢志奇 《计量科学与技术》 2023年第4期18-27,共10页
大尺寸计量中广泛采用增量式激光干涉仪作为量值传递的计量标准,在测量过程中易发生断光影响,严重限制测量灵活性。近年来,以飞秒光学频率梳为光源的高精度绝对测距方法得到了迅猛发展,特别是双光梳异步光学采样绝对测距方法,利用具有... 大尺寸计量中广泛采用增量式激光干涉仪作为量值传递的计量标准,在测量过程中易发生断光影响,严重限制测量灵活性。近年来,以飞秒光学频率梳为光源的高精度绝对测距方法得到了迅猛发展,特别是双光梳异步光学采样绝对测距方法,利用具有微弱重频差的两台飞秒光学频率梳能够实现大量程、高精度和高更新率的绝对距离测量。以大尺寸激光绝对测距和飞秒光学频率梳绝对测距为切入点,详细综述了现阶段大尺寸双光梳绝对测距的研究进展;针对大尺寸计量场景分析了双光梳绝对测距现存的瓶颈,并对此开展了双光梳光源搭建与优化、测距精度优化、测距系统设计和测距性能验证等深入研究,最后对双光梳绝对测距在大尺寸计量中未来的应用方向提出了展望。 展开更多
关键词 计量 尺寸计量 长度计量 双光梳系统 绝对测距 可溯源长度标准
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大尺寸先进计量技术研究与进展概述 被引量:2
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作者 李建双 缪东晶 +6 位作者 刘洋 赫明钊 李连福 蒋远林 康瑶 王德利 朱佳祥 《计量科学与技术》 2024年第2期30-39,共10页
大尺寸计量技术是高精度测量或标定大尺寸物体长度、位置姿态和形貌参量的关键技术,在工业制造、大型建造和工业测量等领域具有广泛的应用。伴随先进光学技术、精密测量技术、数据融合技术和工程应用技术的逐步发展,大尺寸计量技术同样... 大尺寸计量技术是高精度测量或标定大尺寸物体长度、位置姿态和形貌参量的关键技术,在工业制造、大型建造和工业测量等领域具有广泛的应用。伴随先进光学技术、精密测量技术、数据融合技术和工程应用技术的逐步发展,大尺寸计量技术同样从技术和应用层面均面临不断革新,诞生一系列大尺寸先进计量新技术,打破传统大尺寸计量中单一量值和离线溯源的瓶颈,逐步向复合参量和原位溯源进行过渡,进一步向实现数字化、扁平化和智能化的高精度大尺寸计量变革。通过介绍大尺寸计量中室内工业测量和室外大地测量中的先进计量技术,为大尺寸计量未来的发展趋势进行了展望和分析,并为先进大尺寸计量技术的进一步发展提供了新思路。 展开更多
关键词 计量 尺寸计量 工业计量 大地测量 量值溯源 复合参量 数字化
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大尺寸坐标测量技术在大型部件装配应用中的若干问题 被引量:17
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作者 马骊群 曹铁泽 +1 位作者 王继虎 孙安斌 《计测技术》 2013年第2期7-11,23,共6页
介绍了便携式坐标测量系统应用在航空航天等领域中需要注意的若干问题,如复杂曲面评价、统一空间测量网、装配调整过程中的回归控制等。通过飞机机翼蒙皮成型模评价、室内GPS测量网的创建、大型紧缩场反射面的拼接装配中回归控制等实例... 介绍了便携式坐标测量系统应用在航空航天等领域中需要注意的若干问题,如复杂曲面评价、统一空间测量网、装配调整过程中的回归控制等。通过飞机机翼蒙皮成型模评价、室内GPS测量网的创建、大型紧缩场反射面的拼接装配中回归控制等实例给出了相应的解决方案。 展开更多
关键词 尺寸计量 装配 复杂曲面 统一空间测量网 回归控制
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大尺寸测量校准技术分析 被引量:2
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作者 张剑宇 《科技风》 2010年第10期213-,222,共2页
随着科技不断发展,传统量值传递系统已不能满足当今工业生产需求。本文对于长度达几十米大尺寸结构的校准装置的精度保证进行分析。首先介绍大尺寸工业测量系统现状,以及相应仪器发展情况,在此基础上对单站激光跟踪仪的校准方法进行具... 随着科技不断发展,传统量值传递系统已不能满足当今工业生产需求。本文对于长度达几十米大尺寸结构的校准装置的精度保证进行分析。首先介绍大尺寸工业测量系统现状,以及相应仪器发展情况,在此基础上对单站激光跟踪仪的校准方法进行具体分析。 展开更多
关键词 尺寸计量 校准技术
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高精度微小尺寸标准
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作者 B.П.ЛИзyHOB 《国外计量》 1990年第1期8-10,共3页
关键词 集成电路 制造工艺 几何尺寸计量 计量标准 光掩膜板 半导体元件
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铁路机车车辆计量检测技术的现状与未来
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作者 曾红 《上海计量测试》 1999年第6期30-34,共5页
本文综合叙述了机车车辆工业计量的发展历史与现状,以及对国外计量检测技术的预测,分析了所面临的技术任务。
关键词 铁路机车车辆 计量检测技术 三维尺寸视觉计量
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Audit Quality, Timely Disclosure, and the Cost of Debt: Tunisian Evidence
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作者 Imen Achek Mohamed Imen Gallali 《Journal of Modern Accounting and Auditing》 2015年第4期194-209,共16页
The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audi... The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audit quality is measured by auditor size (Big 4 versus non-Big 4) and timely disclosure is proxied by earnings reporting lag. Results show that auditor type is negatively associated with the cost of debt. By contrast, the association between earnings announcement lag and the cost of debt is positive and significant. When testing for the moderating effects of industry and listing status, we document that these associations are more pronounced for industrial companies and listed firms. Finally, the period of investigation slightly moderates the examined associations, since financial institutions become more sensitive to the tardy communication of information and less concerned with auditor type following some economic and political troubles in Tunisia between 2010 and 2012. Our findings have policy implications for managers in the Tunisian setting and other developing economies similar to Tunisia given the crucial role played by debt as an important source of external finance for companies. 展开更多
关键词 cost of debt auditor type eamings reporting lag Tunisia
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Spectrum and Binding Energy of an Off-Center Hydrogenic Donor in a Spherical Quantum Dot
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作者 袁建辉 黄锦胜 +2 位作者 尹淼 曾奇军 张俊佩 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第8期369-372,共4页
Off-center impurity effects in a spherical quantum dot are theoretically studied by degenerate perturbationmethod in strong confinement.The energy levels and binding energies are computed for the typical GaAs material... Off-center impurity effects in a spherical quantum dot are theoretically studied by degenerate perturbationmethod in strong confinement.The energy levels and binding energies are computed for the typical GaAs material asfunction of the donor position.The numerical results show the quantum size effect.We note that the energy levels andbinding energies are not only related to the position of donor and the strength of confinement,but also related to thefold of degenerate states.We can see obviously that gaps will appear among the degenerate states and the splitting ofenergy levels and binding energies will appear as the position of the impurity is shifted away off the center. 展开更多
关键词 quantum dots impurity levels binding energy
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Multi-Aspect Value of Measuring Systems and Methods Based on the Results of Roundness Measurements
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作者 Miodrag Hadzistevic Imre Nemedi +2 位作者 Milenko Sekulic Martin Bosak Janko Hodolic 《Journal of Mechanics Engineering and Automation》 2012年第8期514-530,共17页
The increase of quality consciousness brings about the growth of significance of metrological systems. Besides the significance, the level of automatization, flexibility, accuracy, et al. have advanced. The modern mea... The increase of quality consciousness brings about the growth of significance of metrological systems. Besides the significance, the level of automatization, flexibility, accuracy, et al. have advanced. The modern measuring systems are constructed so that nearly all necessary dimensional characteristics can be measured with them. However, conventional measuring systems are provided for particular mode measurements. This research paper presents and compares several conventional and modem measuring systems and methods. The measured value is roundness, one of the basic shapes of cross section in mechanical engineering. This paper arises in search of answers for the question whether conventional measuring techniques and equipments are made redundant because of the modern ones. In what segments and in which criterion are modem methods preferable? 展开更多
关键词 Measuring systems ROUNDNESS V-block method coordinate measuring machine (CMM) rotational datum method(RDM).
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Estimation of Fat-tail Weight by External Fat-tail Dimensions in Lori-Bakhtiari Sheep
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作者 M. A. Talebi M. Vatankhah 《Journal of Agricultural Science and Technology(A)》 2011年第8期1241-1244,共4页
In this study fat-tail weight was estimated by external fat-tail dimensions. External fat-tail dimensions included upper, middle and lower width, length, length of gap, depth, upper and middle circumference recorded o... In this study fat-tail weight was estimated by external fat-tail dimensions. External fat-tail dimensions included upper, middle and lower width, length, length of gap, depth, upper and middle circumference recorded on 1,482 head of Lori-Bakhtiari lambs at 6 months. Of these about 311 lambs were slaughtered at the age of six months. Prediction equations were derived for fat-tail weight by multiple regression analyses with two methods. The results showed that the measure of middle circumference fat-tail was as most important measure in estimation of fat-tail weight. The measure of middle circumference fat-tail accounted for 76 percent of variation in fat-tail weight. The regression equations for predicting fat-tail weight using external fat-tail dimensions obtained from stepwise regression procedure can be estimated only with using from the lower width, length, middle circumference fat-tail and body weight with high acc, uracy (0.92). Average of fat-tail weight estimated in the age of six months in lambs was 2.39 kg. The highest regression coefficient of external fat-tail dimensions on fat-tail weight observed for the length of fat-tail (0.095 kg). Results of the present investigation showed that fat-tail weight in live sheep of Lori-Bakhtiari, could be estimated by measuring external fat-tail dimensions. 展开更多
关键词 External dimensions fat-tail regression Lori-Bakhtiari SHEEP
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万般光彩 规矩之间
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作者 吉怡 朱弘毅 《中国计量》 2024年第9期60-62,共3页
珠宝计量科普是提高市场主体科学素养的重要一环。在宝石鉴定中,现代计量在颜色、重量、尺寸测量等方面都发挥着巨大作用。在宝石分级鉴定和价值评估领域,现代计量技术通过设备的完善、升级和新技术的集成(包括人工智能、机器学习等),... 珠宝计量科普是提高市场主体科学素养的重要一环。在宝石鉴定中,现代计量在颜色、重量、尺寸测量等方面都发挥着巨大作用。在宝石分级鉴定和价值评估领域,现代计量技术通过设备的完善、升级和新技术的集成(包括人工智能、机器学习等),正在逐步克服人工检测的局限性,实现宝石鉴定中的图像识别、自动测量和数据分析等功能,从而提高自身测量的准确性和可靠性,并进一步提高鉴定的效率和质量。展望未来,计量技术无疑将在全面评估珠宝价值、维护交易的公平与透明中扮演重要角色,成为维护健康的社会主义市场经济秩序的重要武器。 展开更多
关键词 宝石分级鉴定 评估标准 颜色 质量 尺寸计量
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激光多边测量网布局优化研究 被引量:14
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作者 任瑜 刘芳芳 +2 位作者 傅云霞 韩瑜 邾继贵 《激光与光电子学进展》 CSCD 北大核心 2019年第1期167-172,共6页
激光多边测量网是基于激光跟踪仪多站测量的大尺寸坐标测量网络。跟踪仪的位置、数目,即网络布局,是影响测量网性能的关键因素。为此,在遗传算法基础上,提出基于网格的布局优化方法。以覆盖能力、测量精度及总体成本作为多目标评价函数... 激光多边测量网是基于激光跟踪仪多站测量的大尺寸坐标测量网络。跟踪仪的位置、数目,即网络布局,是影响测量网性能的关键因素。为此,在遗传算法基础上,提出基于网格的布局优化方法。以覆盖能力、测量精度及总体成本作为多目标评价函数,利用全局网格和局部网格对布局区域进行划分,将全局搜索和局部搜索相配合,无需初始布局即可全局寻优。实验表明,相较于经验布局,该方法更易获得符合测量要求的网络布局,大大降低了对操作人员测量经验的要求,具有良好的实用性。 展开更多
关键词 测量 尺寸计量 多边测量 布局优化 遗传算法 激光跟踪仪
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Energetics of dioxygen binding into graphene patches with various sizes and shapes
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作者 YUMURA Takashi KOBAYASHI Hisayoshi YAMABE Tokio 《Science China Chemistry》 SCIE EI CAS 2012年第5期787-795,共9页
Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Dep... Density functional theory (DFT) calculations were employed to investigate the electronic properties of an H-atom terminated graphene patch (hydrographene) smaller than a rhombic C96H26 structure with zigzag edges. Depending on shapes and sizes of hydrographenes, some hydrographenes have the triplet ground state where unpaired electrons are localized on their zigzag edges. The stability of the triplet spin state is diminished, decreasing the hydrographene sizes. The existence of the localized spin densities allows triplet dioxgen to bind into a hydrographene. According to the DFT calculations, the energetics of the dioxygen bindings is negatively influenced by downsizing hydrographenes, as well as depends on their shapes. The size-and shape-dependences of the dioxygen bindings reflect from the stability of the triplet state of a hydrographene, because its localized unpaired electrons can be utilized to be attached to an unpaired electron of triplet dioxygen. 展开更多
关键词 GRAPHENE size effect edge structure density functional theory calculation PACS number(s): 73.22.-f 73.22.Pr
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A quantum solution to Gibbs paradox with few particles
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作者 DONG Hui CAI ChengYun SUN ChangPu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第10期1727-1733,共7页
We present a fully quantum solution to the Gibbs paradox (GP) with an illustration based on a gedanken experiment with two particles trapped in an infinite potential well. The well is divided into two cells by a solid... We present a fully quantum solution to the Gibbs paradox (GP) with an illustration based on a gedanken experiment with two particles trapped in an infinite potential well. The well is divided into two cells by a solid wall, which could be removed for mixing the particles. For the initial thermal state with correct two-particle wavefunction according to their quantum statistics, the exact calculations show the entropy changes are the same for boson, fermion and non-identical particles. With the observation that the initial unmixed state of identical particles in the conventional presentations actually is not of a thermal equilibrium, our analysis reveals the quantum origin of the paradox, and confirms Jaynes' observation that entropy increase in Gibbs mixing is only due to the including more observables. To further show up the subtle role of the quantum mechanism in the GP, we study the different finite size effect on the entropy change and show the work performed in the mixing process is different for various types of particles. 展开更多
关键词 Gibbs paradox identical particles mixing entropy
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