Quantitative measurement of the charge carrier concentration using dielectric force microscopy

The charge carrier concentration profile is a critical factor that determines semiconducting material properties and device performance.Dielectric force microscopy(DFM)has been previously developed to map charge carrier concentrations with nanometer-scale spatial resolution.However,it is challenging to quantitatively obtain the charge carrier concentration,since the dielectric force is also affected by the mobility.Here,we quantitative measured the charge carrier concentration at the saturation mobility regime via the rectification effect-dependent gating ratio of DFM.By measuring a series of n-type GaAs and GaN thin films with mobility in the saturation regime,we confirmed the decreased DFM-measured gating ratio with increasing electron concentration.Combined with numerical simulation to calibrate the tip–sample geometry-induced systematic error,the quantitative correlation between the DFM-measured gating ratio and the electron concentration has been established,where the extracted electron concentration presents high accuracy in the range of 4×10^(16)–1×10^(18)cm^(-3).We expect the quantitative DFM to find broad applications in characterizing the charge carrier transport properties of various semiconducting materials and devices.

Measurement of forces generated during distraction of growing-rods in early onset scoliosis

AIM: To measure the forces applied during distraction of growing-rods in early onset scoliosis(EOS), aimed at developing a motorized elongation device.METHODS: A consecutive series of measurements were carried out to analyze the forces applied by the surgeon during distraction of single growing-rods in 10 patients affected by EOS(mean age 8.3 years; range 6 to 10 years) undergoing the first distraction 6 months following implantation of the rods. For each measurement, output from the transducer of a dedicated pair of distraction calipers was recorded at zero load status and at every 1 mm of distraction, up to a maximum of 12 mm for each of the two connected rods.RESULTS: Twenty measurements were obtained showing a linear increase of the load with increasing distraction, with a mean peak force of 485 N at 12 mm distraction and a single reading over 500 N. We did not observe bone fractures or ligament disruptions during or after rod elongations. There was one case of superficial wound infection in the cohort.CONCLUSION: The safe peak force carrying capacity of a motorized device for distraction of growing-rods is 500 N.

Environmental temperature effect on dimensional measurements of atomic force microscopy

Atomic force microscopy(AFM)is increasingly being used as a fundamental tool for dimensional measurements at the nanoscale in the laboratory and in industry.Since the environmental temperature is not controlled in many measurements,or is even varied on purpose,quantification of its effects on AFM dimensional measurements is needed.In this paper,the influences of the temperature in the entire environment of the AFM(excluding only the controller and computer)and that in the local environment around the tip–sample are investigated.The results show that lateral dimensional measurements are affected mainly by the entire environmental temperature.However,vertical measurements are influenced by the temperature of both the entire environment and the local environment.The effects become significant for temperatures higher than some threshold,here between 35 and 40 XC.

An Application of Force Sensor to Impact Measurement

ＡｎＡｐｐｌｉｃａｔｉｏｎｏｆＦｏｒｃｅＳｅｎｓｏｒｔｏＩｍｐａｃｔＭｅａｓｕｒｅｍｅｎｔ￥（李邦宜）（邓樱）（王莉）（申杰ＬＩＢａｎｇｙｉ；ＤＥＮＧＹｉｎｇ；ＷＡＮＧＬｉ；ＳＨＥＮＪｉｅ（ＭｅａｓｕｒｅｍｅｎｔＣｅｎｔｅｒ，ＨａｒｂｉｎＩｎｓｔｉｔ...

Analysis of Photoelectric Hybridization Measurement on Shearing Force for Flat Shearer

This paper introduces a kind of photoelectric hybridization measuring process.Owing to the characteristics of the compact form of shearing equipment to be analyzed and the connecting rod existing in two directional stress state during operation etc.,it is hard to obtain results by means of single electrical testing process.For this reason,this paper derives a group of calculation formulas of hybridization measuring process through comprehensive discussion of photoelectric analysis and electrical testing theories,thus providing an analytical method for actual measurement of complex engineering problems.

An appraisal of techniques and equipment for cutting force measurement

Current research focussed on the assessment of metal machining process parameters and on the development of adaptive control, shows that machine performance, work-piece and tool material selections, tool life, quality of machined surfaces, the geometry of cutting tool edges, and cutting conditions are closely related to the cutting forces. This information is of great interest to cutting tool manufactures and users alike. Over the years there have been significant developments and improvements in the equipment used to monitor such forces. In 1930 mechanical gauges were replaced by resistance strain gauges, and some 30 years later compact air gauge dynamometers were invented. Since this time intensive research has continued being directed to- wards developing new approaches to cutting force measurement. The Kistler Company, well-known manufacturer of acceleration and piezoelectrical dynamometers, has worked in this field for more than three decades, and developed very sensitive devices. While leading manufacturing research laboratories are often equipped with this technology, classical electrical strain gauges and other dynamometers of individual designs are still commonly used in industry. The present paper presents data obtained using different techniques of force measurement in metal machining processes. In particular, areas of uncertainties, illustrated through results concerning the turning process, are analysed, leading to an appraisal of the current status of these measurements and their significance.

Wheel/rail-force–based maintenance interval extension of the C80 series wagon

Purpose–This study aims to introduce the achievements and benefits of applying wheel/rail-force–based maintenance interval extension of the C80 series wagon in China.Design/methodology/approach–Chinese wagons’existing maintenance strategy had left a certain safety margin for the characteristics of widely running range,unstable service environment and submission to transportation organization requirements.To reduce maintenance costs,China railway(CR)has attempted to extend the maintenance interval since 2020.The maintenance cycle of C80 series heavy haul wagons is extended by three months(no stable routing)or 50,000 km(regular routing).However,in the meantime,the alarming rate of the running state,a key index to reflect the severe degree of hunting stability,by the train performance detection system(TPDS)for the C80 series heavy haul wagons has increased significantly.Findings–The present paper addresses a big data statistical way to evaluate the risk of allowing the C80 series heavy haul wagons to remain in operation longer than stipulated by the maintenance interval initial set.Through the maintenance and wayside-detectordata,whichis divided intothreestages,the extension period(three months),the current maintenance period and the previous maintenance period,this method reveals the alarming rate of hunting was correlated with maintenance interval.The maintainability of wagons will be achieved by utilizing wagon performance degradation modeling with the state of the wheelset and the often-contact side bearing.This paper also proposes a statistical model to return to the average safety level of the previous maintenance period’s baseline through correct alarming thresholds for unplanned corrective maintenance.Originality/value–The paper proposes an approach to reduce safety risk due to maintenance interval extension by effective maintenance program.The results are expected to help the railway company make the optimal solution to balance safety and the economy.

An experimental study:Integration device of Fiber Bragg grating and reinforced concrete beam for measuring debris flow impact force

The impact effect of boulder within debris flow is the key factor contributing to peak impact as well as to the failure of debris flow control work. So accurate measuring and calculating the impact force of debris flow can ensure the engineering design strength. However, limited to the existing laboratory conditions and piezoelectric sensor performance, it is impossible, based on the conventional measurements, to devise a computing method for expressing a reliable boulder impact force. This paper has therefore designed a new measurement device according to the method of integrating Fiber Bragg grating(FBG) and reinforced concrete composite beam(RCB) for measuring the impact force of debris flows, i.e. mounting FBG on the axially stressed steel bar in the composite beam at regular intervals to monitor the steel strain. RCB plays the role of contacting debris flow and protecting FBG sensors. Taking this new device as the experimental object, drop testing is designed for simulating and reflecting the boulder impact force. In a series of impacting tests, the relationship between the peak dynamic strain value of the steel bar and the impact force is analyzed, and based on which, an inversion model that uses the steel bar strain as the independent variable is established for calculating the boulder impact force.The experimental results show that this new inversion model can determine the impact force value and its acting position with a system error of 18.1%, which can provide an experimental foundation for measuring the impact force of boulders within the debris flow by the new FBG-based device.

Wireless measurement of orthodontic forces in invisible aligners

Invisible orthodontic treatment is an effective form of malocclusion treatment favored in recent years.The magnitude of its orthodontic force has a crucial impact on the outcome of the treatment and has gained a high level of clinical interest.However,there are very few explorations of in vivo measurements of orthodontic force,and existing studies are limited to a large number of couplings,which are inconvenient for clinical use.In this work,we developed a wireless flexible measurement system that allows quantitative measurement of the orthodontic force of an invisible aligner on a dental model.The system is wireless,tiny,flexible,fast responding,and has a range suitable for the range of orthodontic forces.We show the difference in the orthodontic force applied to different tooth positions and the difference in the orthodontic force applied to different positions of the same tooth.In addition,the system can evaluate the mechanical differences between aligners of different brands and materials as well as the deviation of fabrication results.This system provides a test tool and evaluation method for future real-time assessment of clinical orthodontic forces.

Enhancing force sensing in a squeezed optomechanical system with quantum nondemolition measurement

A theoretical scheme is proposed to enhance the sensitivity of force sensors with quantum nondemolition measurement(QND)in an optomechanical setup assisted by four-tone optical driving and an optical parametric amplifier(OPA).With the help of special drive,the system can be simplified as the typical type of QND for force sensing,so that the backaction noise can be evaded to surpass the standard quantum limit.Besides,the added noise can be suppressed owing to the modified optical susceptibility resulting from the OPA.By introducing two oscillators coupling with two charged bodies respectively,the signal can be enhanced with the nonlinearity caused by Coulomb interaction,while the noise presents an exponential decrease.Moreover,considering the homodyne detection effect,the range of system parameters and frequency bands will be broadened.The present investigation may provide a route toward simultaneously evading backaction noise,reducing the mechanical thermal noise,and enhancing the external signal,which can be an alternative design for sensitive devices.

Numerical simulation and parameter optimization of Coriolis force scale measurement process based on DEM

The Coriolis force method is a recently developed and highly regarded direct measurement technique that enables high-precision measurement of bulk materials.The operational parameters and variations thereof directly influence the measurement accuracy of the equipment.In this study,a measurement correction coefficient is introduced to improve the calculation method for mass flow rate of the materials.The DEM is employed to simulate the motion of particle groups within the Coriolis force scale under different parameters,and the effects of various structural and operational parameters on the measurement results are compared.The research findings indicate that a lower rotational speed leads to more stable instantaneous measurement results,although the measurement error is relatively large.When the rotational speed exceeds 300 rpm,the measurement error remains within 15%.For materials with a radius of 1–2 mm,the variation range of precision error is approximately 0.4%.Among the structural parameters,the radius of the measurement wheel has the most significant impact on the measurement results,wherein a larger measurement wheel radius corresponds to a smaller measurement error.The horizontal angle of the blades follows as the next influential parameter,with a clockwise rotation and a horizontal angle of 30°resulting in a measurement error below 2%.

AN OPTICAL FIBRE SENSOR BASED CUTTING FORCE MEASURING DEVICE

A cutting force measuring device is developed which is composed of a common tool shank and an optical fibre sensor. The sensor is mounted at the rear of the shank and the deformation of the shank caused by cutting force is detected as the measurement of cutting force. The device possesses good adaptability to workshop conditions as well as satisfying static and dynamic performances.

A New Study to Compensate Dynamic Measuring Error of Serial Multiple Degree of Freedom（DOF） Strain Gauge Force Sensor

ＡＮｅｗＳｔｕｄｙｔｏＣｏｍｐｅｎｓａｔｅＤｙｎａｍｉｃＭｅａｓｕｒｉｎｇＥｒｒｏｒｏｆＳｅｒｉａｌＭｕｌｔｉｐｌｅＤｅｇｒｅｅｏｆＦｒｅｅｄｏｍ（ＤＯＦ）ＳｔｒａｉｎＧａｕｇｅＦｏｒｃｅＳｅｎｓｏｒＣＡＩＨａｉｎａｎ；ＪＩＡＮＧＺｕｏｍｉｎ；ＱＩＡ...

Design and research of measuring system of clamping force of hemostats

Reliability of medical instruments such as hemostats is extremely important because these instruments are used in patients who are in critical condition. Clamping force of hemostats, as an important parameter of hemostats, should be detected. However, it could not be tested directly. In order to test it, a testing system has been put forward. The system is comprised of sensor, acquisition card, and three-way tap and so on. This system is controlled by a computer. The testing system has been proved to be effective in testing the clamping force of hemostats.

基于VR-Forces的水面舰艇防空作战仿真

作战模拟是水面舰艇对空防御研究的有效手段之一,VR-Forces为此提供了有力的支持。首先建立了基于VR-Forces的舰空对抗仿真系统,分析了基于VR-Forces组件式作战兵力实体结构特点,提出了基于功能组件的实体结构元模型;在电子对抗模型的基础上,以雷达告警仿真为例建立了基于VR-Forces的水面舰艇对空防御仿真组件开发过程,对组件及组件间的数据流程进行详细说明。所提出的开发方法已经成功运用于多型作战模拟训练系统中,实现了电磁环境下的舰空对抗训练。

A Study of Lift Force and Instantaneous Velocity Field Around an Oscillating Circular Cylinder

Force measurements of oscillatory flow acting on a single circular cylinder have been carried out. The experiments were done by oscillating a circular cylinder in still water. Instantaneous forces and velocity fields around the cylinder were measured by Particle Image Velocimetry (PIV). The Keulegan-Carpenter number (KC) varied in the range from 5 to 20 and the viscous parameter beta = Re / KC was set at 500 (Re is Reynolds number). It was found that the strength and frequency of the lift force increased with KC number, the main frequency of the lift force being three times the frequency of the oscillatory flow at KC = 20. The movement and strength of the vortices around the cylinder are discussed for different KC numbers.

Problems in the Transfer of Rural Surplus Labor Force in Chengdu Plain——A Empirical Analysis of Xiyu Village,Gexianshan Town,China

Under the new situation of the coordination of rural and urban development,the employment and transfer of surplus labor force have become the major social problems in China.Based on the field investigation on Xiyu Village of Gexianshan Town in Pengzhou City,the surplus labor force and the absorptive capacity of non-agricultural industries are estimated by using per capita cultivated method and output value absorption method.Based on this,the transfer pattern of surplus labor force is generalized and the corresponding suggestions for transfer are put forward.

Monitoring film coalescence from aqueous polymeric dispersions using atomic force microscopy: Surface topographic and nano-adhesion studies

The aim of the investigation was to develop the use of topographic and nano-adhesion atomic force microscopy(AFM) studies as a means of monitoring the coalescence of latex particles within films produced from a pharmaceutically relevant aqueous dispersion(Eudragit~?NE30 D). Films were prepared via spin coating and analysed using AFM, initially via tapping mode for topographic assessment followed by force-distance measurements which allowed assessment of site-specific adhesion. The results showed that colloidal particles were clearly observed topographically in freshly prepared samples, with coalescence detected on curing via the disappearance of discernible surface features and a decrease in roughness indices. The effects of temperature and humidity on film curing were also studied, with the former having the most pronounced effect. AFM force measurements showed that the variation in adhesive force reduced with increasing curing time, suggesting a novel method of quantifying the rate of film formation upon curing. It was concluded that the AFM methods outlined in this study may be used as a means of qualitatively and quantitatively monitoring the curing of pharmaceutical films as a function of time and other variables, thereby facilitating rational design of curing protocols.

Experimental Investigations of Axial Force Monitoring and Control for Friction Stir Welding Process

Friction stir welding( FSW) is a solid-state welding process that utilizes a rotating tool to induce gross material plastic deformation and join two parts together. A large number of studies have indicated that axial force control can be used to achieve good welding quality. However,in the welding process,due to workpiece's geometry error,improper clamping and other process variations,the axial force can vary significantly and produce welding defects.The control of force in the process of FSW is investigated. At first,the development and evaluation of a closed-loop control system is described,which is equipped with a custom real-time wireless force dynamometer for FSW. Then,an axial force controller is designed based on nonlinear force controllers for FSW. Experimental validations are carried out on an FSW platform. The experimental results demonstrate that the controller maintains the constant axial force and shows desirable dynamic behavior, even when the disturbance is encountered during the welding process.