共查询到20条相似文献，搜索用时 46 毫秒
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正一、引言我国气体活塞式压力计研制起步较晚,技术落后,大部分依靠进口。进口产品价格昂贵,售后繁琐,严重制约了我国计量体系建设和计量技术发展。面对国内紧迫的需求,急需研制一套高准确度的气体活塞式压力计。二、气体活塞式压力计基本原理和组成部分1.基本原理气体活塞式压力计是基于流体静力平衡原理(即作用在活塞有效面积上的流体压力与其所负荷的重 相似文献
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为了提高定量自动衡器的准确性和稳定性,通过对定量自动衡器装置的结构特点进行研究,针对不同类型的定量自动衡器,选择合适的检定方法进行计量检定并计算误差。通过计算最大允许偏差和最大允许预设值偏差与标准偏差的比值,确定定量自动衡器的准确度等级。 相似文献
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本文根据JJF1326-2011质量比较仪校准规范,分析质量比较仪(以下简称比较仪)校准时校准砝码对校准结果不确定度的贡献,探讨用相对较低等级的标准砝码开展比较仪校准、减少校准成本的可能。 相似文献
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2014年01月21日,中国北京消息--福禄克公司进一步丰富其精密压力校准产品线,推出新款700G系列精密压力计和两款新型压力校准器： FLUKE ？719PRO和721双量程压力校准器。量程从0．36至10,000 PSI,具有18种不同的工程单位可选,允许用户对仪表进行定制,以满足客户各种特殊的压力校准需求。从此,仪器仪表、过程及工厂维护技术人员能够拥有完备的校准设备,坚固耐用、值得信赖。 相似文献
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正福禄克公司为了进一步丰富其精密压力校准产品线,日前推出新款700G系列精密压力计和两款新型压力校准器:Fluke 719Pro和721双量程压力校准器。700G系列精密压力计的压力量程为10inH2O/20mbar至10000psi/690bar,0.05%的新绝压测量准确度,以及新参考级表压测量准确度达0.04%。700G系列精密压力计与Fluke 700PTPK或700HTPK配合使用时,即可实福禄克推出新型压力校准产品满足仪器仪表技术人员的准确度和量程需求R 相似文献
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新疆维吾尔自治区的某次精密压力表检定技术比武活动中,选用的是测量范围为(0~6)MPa、准确度等级为0.4级的弹簧管式精密压力表;标准器选用的是测量范围为(0.1~6)MPa、准确度等级为0.05级的活塞式压力计。活塞式压力计在检定周期内使用。实验室的环境条件符合JJG49-1999《弹簧管式精密压力表和真空表》检定规程的要求。 相似文献
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Liangsong Huang;Shuo Wang;Peng Zhang;Kun Zhang;Yuxia Li;Zhifu Chen; 《Advanced Materials Technologies》2024,9(4):2301377
Flexible pressure sensor is widely used in fields such as healthcare, intelligent prosthetics, and patient rehabilitation. However, how to ensure high sensitivity of the sensor while having a wide detection range remains a challenge. In order to address this challenge, a flexible pressure sensor with a wide detection range based on capacitive-piezoresistive dual mode conversion is proposed. By manufacturing circular through-holes on the dielectric layer of the sensor, the microstructure of the upper and lower electrode layers can achieve non-contact and contact switching under different pressures through the through holes. This means that the sensor remains in capacitive mode at low pressure and then in piezoresistive mode at high pressure. By cleverly combining the two modes, the measurement range can reach 2 000 kPa and high sensitivity can be maintained during mode switching. In addition, its production process is simple, the cost is low, and it has a fast response time (120 ms) and good repeatability stability. The experimental results indicate that the sensor can achieve ideal performance in proximity detection, human behavior monitoring, and ultra high-pressure detection, and has broad application prospects in providing a more powerful human-computer interaction interface and expanding more comprehensive health monitoring. 相似文献
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This study provides a simple nanoparticle–water system for enhancing the water evaporation in a low‐cost and energy‐efficient way. The particle–water system is achieved by depositing a layer of hydrophobic silica nanoparticles onto the water surface. The influence of the locally curved water surface, generated by interfacial nanoparticles, to the water evaporation rate is investigated. The experimental results show that the coverage of nanoparticle layer on the water surface enhances the water evaporation flux. A theoretical model based on Kelvin equation is proposed to explain the evaporation enhancement with the local curvature of water surface distorted by hydrophobic nanoparticles on water surface. The major influencing factors on the water evaporation enhancement are found to involve the coverage of nanoparticle layer, surface concentration of nanoparticles, and surface tension of water. The experimental findings offer a novel protocol for evaporation enhancement during water purification and salt mining. 相似文献
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A dual level high pressure cell using Bridgman anvils was constructed to facilitate simultaneous measurement on the samples.
The anvils were of 4 mm and 5 mm diameter respectively. The anvils were made from tungsten carbide (3% cobalt binder). Pyrophyllite
and steatite were used as the gasket and the pressure transmitting medium. The cell was calibrated against the polymorphic
phase transition of bismuth and ytterbium. 相似文献
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Xing Tang Congyi Wu Lin Gan Tian Zhang Tingting Zhou Jin Huang Hao Wang Changsheng Xie Dawen Zeng 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(10)
Flexible pressure sensors as electronic skins have attracted wide attention to their potential applications for healthcare and intelligent robotics. However, the tradeoff between their sensitivity and pressure range restricts their practical applications in various healthcare fields. Herein, a cost‐effective flexible pressure sensor with an ultrahigh sensitivity over an ultrawide pressure‐range is developed by combining a sandpaper‐molded multilevel microstructured polydimethylsiloxane and a reduced oxide graphene film. The unique multilevel microstructure via a two‐step sandpaper‐molding method leads to an ultrahigh sensitivity (2.5–1051 kPa?1) and can detect subtle and large pressure over an ultrawide range (0.01–400 kPa), which covers the overall pressure regime in daily life. Sharp increases in the contact area and additional contact sites caused by the multilevel microstructures jointly contribute to such unprecedented performance, which is confirmed by in situ observation of the gap variations and the contact states of the sensor under different pressures. Examples of the flexible pressure sensors are shown in potential applications involving the detection of various human physiological signals, such as breathing rate, vocal‐cord vibration, heart rate, wrist pulse, and foot plantar pressure. Another object manipulation application is also demonstrated, where the material shows its great potential as electronic skin intelligent robotics and prosthetic limbs. 相似文献
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硅压力传感器具有小型和高灵敏等的优点,近年来小型高灵敏度的压力传感器的量程已低到１ｋＰａ。在这一发展过程中硅弹性体结构的改进起了很大的作用,本文介绍了作者首先提出了适用于微压压力传感器的梁膜（岛）结构以及以后几年来出现的相近的结构,用这些结构都已制成量程为１ｋＰａ的压力传感器 。 相似文献
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对压力容器在压力试验过程中所用两个量程相同并且经过校验的压力表出现误差值的判断进行论述,同时给出受温度影响导致压力表指针示值误差控制范围的计算公式,以确保试验压力值的正确性。 相似文献
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Cumulative pulses detection with appropriate cumulative pulses number and threshold has the ability to improve the detection performance of the pulsed laser ranging system with GM-APD. In this paper, based on Poisson statistics and multi-pulses cumulative process, the cumulative detection probabilities and their influence factors are investigated. With the normalized probability distribution of each time bin, the theoretical model of the range accuracy and precision is established, and the factors limiting the range accuracy and precision are discussed. The results show that the cumulative pulses detection can produce higher target detection probability and lower false alarm probability. However, for a heavy noise level and extremely weak echo intensity, the false alarm suppression performance of the cumulative pulses detection deteriorates quickly. The range accuracy and precision is another important parameter evaluating the detection performance, the echo intensity and pulse width are main influence factors on the range accuracy and precision, and higher range accuracy and precision is acquired with stronger echo intensity and narrower echo pulse width, for 5-ns echo pulse width, when the echo intensity is larger than 10, the range accuracy and precision lower than 7.5 cm can be achieved. 相似文献