RIGOROUS PROOF FOR CHARACTERISTICS OF PRACTICABLE MAGNETIC POTENTIOMETERS AND THEIR APPLICATION

The characters of practicable magnetic potentiometers have not been rigorously proved. This paper deduced a mathematical description of mutual inductance of the cylindricalmagneticpotentiometerwithfinite turns crosssection and verifies that M is independent of the position with respect to the primary circuit and is unaffected by stray fields of current not linked with them. Using these features, a novel device is designed to measure ACcurrent of the measuring range 0~4 000 A. The experimental result shows the measuring error is less than 1%.The device holds various advantages: such as the fixed number of turns of the primary winding, low cost, small size and weight. This paper pointed out that if the device is used to measure the nonsinusoidal signal, an integrator can increase the accuracy.

西门子Siregraph CF机维修实例

我院的西门子Siregraph CF X线机1998年购买使用,经过十来年的使用,设备相对比较旧,故障发生率较高,我们将多年来维修此机的一些有关点片系统片盒不识片的故障做些介绍。此机片盒的大小规格是通过两个绕着钢丝绳的电位器Format Sensing 3PT10、3PT11(3PT10对应Width、3PT11对应Height)的不同的阻值决定的,而电位器Format Sensing 3PT10、3PT11电缆线是绕在一个伸缩的曲臂上,片盒的更换和点片时的曝光,都需要曲臂的运动,在每天的使用中,这个曲臂就需要做无数次的伸缩运动,所以曲臂上的电缆线就极易折断。在这些故障中,大部分都可以利用替代的配件就可以修复机器,避免了向厂家订购配件的麻烦,同时也降低了维修成本。

Development of Flexible Spherical Actuator with 3D Coordinate Measuring Device

Rehabilitation devices help to recover the physical abilities of patients. This study aims to develop a portable rehabilitation device that is safe to use when?patients are holding it by hands. In a previous study, to realize a home rehabilitation device, a flexible spherical actuator that can provide motion to patients was developed. In this study, to measure the relative position between both handling stages, a 3D coordinate measuring device using three wire-type linear potentiometers and an embedded controller was proposed and tested. In this paper, the spherical actuator with built-in 3D coordinate measuring device is described. The measuring method and experimental results obtained are also presented. The tracking position control of the actuator using the measuring device was carried out. As a result, the position of the handling stages can be successfully controlled using the feedback signal from the tested?measuring device.

A Study on Measurement of Forest Soil Redox Potential

Redox potential has principal influences on formation and attribute of soils and it is necessary to research the measurement of soil redox potential. The self-made potentiometer and two indigenous FJA-5 potentiometers were employed to measure the Eh values of fir forest soils in situ, which lied in Savage Sea Beauty Spot in Sichuan Province. Simultaneously fresh soils in situ were collected and made into suspensions with various soil-water ratios and standing time to measure Eh values. The results demonstrated that the total tendency of Eh values measured by the self-made potentiometer was gradually falling with soil-water ratios increasing and standing time prolonging. There is a great difference between Eh values measured in laboratory and in situ. Only in situ may the measured Eh values show realistic oxidation-reduction conditions and formation characteristics of forest soil. The self-made potentiometer has a preferable performance than indigenous FJA-5 potentiometers and it can be applied to measuring forest soil Eh in situ.

Research on the enhancement of signal-to-noise ratio of light-addressable potentiometric sensor by optical focusing

For enhancing the response of light-addressable potentiometric sensor(LAPS) and further improving its signal-to-noise ratio(SNR),an optical focusing method is adopted.Experimental research and theoretical analysis reveal that the magnitude of responsive signal is increased by optical focusing,and the SNR is improved remarkably.These research results indicate that the optical focusing is an effective approach for improving SNR of LAPS.

Effects of Bentonite,Hydrogel and Biochar Amendments on Soil Hydraulic Properties from Saturation to Oven Dryness

Effects of hydrogel, bentonite, and biochar as soil amendments on soil hydraulic properties and improving water availability from saturation to oven dryness were investigated. Soils were mixed with hydrogel (0.10%, 0.25%, and 0.50%), bentonite (0.5%, 1.0%, and 2.5%), and biochar (1.0%, 2.5%, and 5.0%) as soil amendments (weight:weight). Three methods (extended multistep outflow (XMSO), evaporation (EVA), and WP4 dewpoint potentiometer) were used to measure soil hydraulic properties from saturation to oven dryness. The cumulative XMSO results were more uniform across all the applied pressure steps for the amended soils. The EVA exhibited a shorter linear decrease during the first evaporation stage and a lower evaporation rate during the second evaporation stage. The WP4 results also exhibited that soil amendments increased the soil water content of the amended soils at low matric potentials. The results of soil water retention curves revealed that the unamended soil retained less water at any matric potential compared to the amended soils. Soil hydraulic conductivity decreased with increasing amount of soil amendments. The saturated hydraulic conductivity was higher for the unamended soil than the soils amended w计h 2.5% bentonite, 0.50% hydrogel, and 5.0% biochar by 11, 3, and 18 times, respectively. These results suggested that soil amendments improved soil water retentivity, which confirmed the appropriateness of these soil amendments for potential use in sandy soil improvements. However, field experiments and economical perception studies should be considered for further investigation.

Enzyme-loaded liposome with biocatalytic precipitation for potentiometric immunoassay of thyroid-stimulating hormone in thyroid carcinoma

A simple and feasible potentiometric immunosensing platform based on enzymatic biocatalytic precipitation technique was designed for the sensitive detection of thyroid-stimulating hormone(TSH;a typical kind of biomarkers for thyroid carcinoma),using horseradish peroxidase(HRP)-loaded liposome for the signal amplification.To construct such an assay system,a sandwich-type immunoreaction was readily carried out on monoclonal anti-TSH capture antibody-coated electrode by using polyclonal antiTSH secondary antibody-conjugated HRP-loaded liposome.Accompanying the formation of sandwichtype immunocomplex,the carried liposome was lysed through the added Triton X-100 to release the entrapped HRP molecules,which catalyzed the oxidation of 4-chloro-1-naphthol to produce an insoluble and uncharged organic precipitation on the electrode surface,thereby causing the change of the local electrical potential.Two labeling protocols with and without the liposome were investigated for detection of target TSH,improved analytical features were achieved with HRP-entrapped liposome.Under optimal conditions,the potentiometric immunosensor had good responses for TSH detection within the linear range of 0.01-30 p IU/mL at a detection limit of 0.0067 p IU/mL.Good reproducibility,high specificity and long-time stability were acquired during the assay procedure.Importantly,a wellmatched accuracy between the potentiometric immunosensor and commercial human TSH ELISA kit was gave for the analysis of human serum samples.