The applicable value of respiratory impedance for the stage 0 of chronic obstructive pulmonary disease

Objective ：To evaluate the applicable value of respiratory impedance for the stage 0 of chronic obstructive pulmonary disease （COPD）. Methods：Respiratory impedance was measured by impulse oscillometry （lOS） in 41 cases at stage 0 of COPD （NHLBI/WHO, 2001 Standard） and their conventional pulmonary function values were compared with 42 healthy subjects. Both groups had no significant deviation in age, stature and avoirdupois, etc. Master-Screen pulmonary function test system （Jaeger Co, Germany） were used to determine IOS parameters including viscous resistance of 5Hz, 20 Hz and 35Hz （R5, R20, R35）, reactance of 5Hz, 35 Hz （X3, X35）, resonant frequency （Fres） ,total respiratory impedance （Zrs） and routine pulmonary function values including forced expiratory volume in one second to predicted value （FEV1 % ）, forced expiratory volume in one second to forced vital capacity ratio（ FEV1/ FVC% ）, maximal mid expiratory flow （MMEF%）,V23% and V50%. Results：Both groups had no significant deviation in FEV1%, FEV1/FVC% and X35（P〉0.05）. It was increased significantly in viscous resistance of 5Hz, 20 Hz and 35Hz （R5, R20, R35） in COPD group than that in healthy group （P〈0.01）. So were Fres and Zrs （P〈0.01）. MMEF%,V25%,V50% and reactance of 5Hz （X5） in COPD group were marked lower than that in healthy group （P〈0.01）. The sensitivity of MMEF%, V25%,V50% was higher than others, but its specificity was lower. In parameters of IOS, Fres was the most sensitive index for diagnosis of the small airway function and its specificity was higher than that of MMEF%, V25% ,V50%. Conclusion：In the risk case at the stage 0 of COPD, MMEF%, V25% and V50% could be decreased, but Fres, R5 ,R5-20 could be increased in spite of FEV1% and FEV1/FVC% in normal range.

In Situ Acquisition of Equivalent Circuit Parameters of Crystal Resonance during Copper Deposition and Dissolution in Acidic Solution by Electrochemical Quartz Crystal Impedance System

Electrochemical quartz crystal impedance system (EQCIS) which allows in situ dynamic quartz crystal impedance measurement in an electrochemical experiment was developed by combining an HP 4395A Network/Spectrum/Impedance analyzer with an EG&G M283 potentiostat. Equivalent circuit parameters of crystal resonance change significantly during electrodeposition and dissolution of copper in 0.1 mol/L H2SO4 aqueous solution in a cyclic potential sweep experiment, which is explained with an overall picture of mass loading, solution density and viscosity, etc..

High Impedance Fault Detection of Distribution Network by Phasor Measurement Units

This paper proposes a new algorithm for High Impedance Fault (HIF) detection using Phasor Measurement Unit (PMU). This type of faults is difficult to detect by over current protection relays because of low fault current. In this paper, an index based on phasors change is proposed for HIF detection. The phasors are measured by PMU to obtain the square summation of errors. Two types of data are used for error calculation. The first one is sampled data and the second one is estimated data. But this index is not enough to declare presence of a HIF. Therefore another index introduces in order to distinguish the load switching from HIF. Second index utilizes 3rd harmonic current angle because this number of harmonic has a special behaviour during HIF. The verification of the proposed method is done by different simulation cases in EMTP/MATLAB.

Improvement Design of Biochip Towards High Stable Bioparticle Detection Utilizing Dielectrophoresis Impedance Measurement

Dielectrophoresis impedance measurement(DEPIM)is a powerful tool for bioparticle detection due to its advantages of high efficiency,label-free and low costs.However,the strong electric field may decrease the viability of the bioparticle,thus leading to instability of impedance measurement.A new design of biochip is presented with high stable bioparticle detection capabilities by using both negative dielectrophoresis(nDEP)and traveling wave dielectrophoresis(twDEP).In the biochip,a spiral electrode is arranged on the top of channel,while a detector is arranged on the bottom of the channel.The influence factors on the DEP force and twDEP force are investigated by using the basic principle of DEP,based on which,the relationship between Clausius-Mossotti(CM)factor and the frequency of electric field is obtained.The two-dimensional model of the biochip is built by using Comsol Multiphysics.Electric potential distribution,force distribution and particle trajectory in the channel are then obtained by using the simulation model.Finally,both the simulations and experiments are performed to demonstrate that the new biochip can enhance the detection efficiency and reduce the negative effects of electric field on the bioparticles.

Analysis of a Large Grounding System and Subsequent Field Test Validation Using the Fall of Potential Method

This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.

Development of Instrumentation for the Measurement of the Performance of Acoustic Absorbers

In both fixed and rotary wing aircraft, the move toward lighter structures has resulted in an increase in structural vibration and interior noise. Porous materials have been proposed as acoustic absorbers to reduce this noise. This paper discusses the development of equipment at the NASA Glenn Research Center for characterizing the acoustic performance of porous materials: a flow resistance apparatus to measure the pressure drop across a specimen of porous material, and a standing wave tube that uses a pair of stationary microphones to measure the normal incidence acoustic impedance of a porous material specimen. Specific attention is paid to making this equipment as flexible as possible in terms of specimen sizes need for testing to accommodate the small or irregular sizes often produced during the development phase of a new material. In addition, due to the unknown performance of newly developed material, safety features are included on the flow resistance apparatus to contain test specimens that shed particles or catastrophically fail during testing. Results of measurements on aircraft fiberglass are presented to verify the correct performance of the equipment.

Longitudinal impedance measurements and simulations of a three-metal-strip kicker

A kicker is a critical component for beam injection and accumulation in circular particle accelerators. A ceramic slat kicker plated with a TiN conductive coating was applied in the Beijing Electron Positron Collider (BEPCII). However, the ceramic slat kicker has experienced several sudden malfunctions during the operation of the BEPCII in the past. With a reliable kicker structure, a three-metal-strip kicker can substitute the original ceramic slat kicker to maintain the operational stability of the BEPCII. A comparison of the numerical simulation was conducted for three kicker models, demonstrating the comprehensive advantage of the three-metal-strip kicker. Furthermore, impedance bench measurements were conducted on a prototype of a three-metal-strip kicker. The longitudinal beam-coupling impedance was measured using a vector network analyzer via the coaxial wire method. A satisfactory agreement was obtained between the numerical simulations and measurements. Based on the numerical simulation data, the loss factor was 0.01721 V/pC, and the effective impedance was 3.59 mΩ(σ=10 mm).The simulation of the heat deposition on each part of the kicker demonstrated that 84.4%of the parasitic loss of the beam was deposited on the metal strips, and the total heat deposition power on the kicker was between 113.3 and 131.5 W. The obtained heat deposition powers can be considered as a reference for establishing the cooling system.

Research on an active and continuous monitoring system for human respiratory system

Continuous and dynamic measurements of human respiratory parameters are very important for vital diseases of respiratory system during mechanical ventilation. This paper analyzed the structure and mechanical properties of the human respiratory system, and designed an active intervening monitoring micro system for it. The mobile mechanism of the micro system is soft and earthworm-like movement actuated by pneumatic rubber actuator, the measurement and therapy unit of the system is an extensible mechanism with sensors in the front. The micro monitoring system can move in respiratory tract and measure the respiratory parameters in bronchium continuously. Experiments had been done in swine＇s respiratory tract, the results proved that the micro robot system could measure the respiratory parameters in real-time successfully and its movement was smith in swine＇s respiratory tract.

Relationships between the sound speed ratio and physical properties of surface sediments in the South Yellow Sea

Building empirical equations is an effective way to link the acoustic and physical properties of sediments.These equations play an important role in the prediction of sediments sound speeds required in underwater acoustics.Although many empirical equations coupling acoustic and physical properties have been developed over the past few decades,further confirmation of their applicability by obtaining large amounts of data,especially for equations based on in situ acoustic measurement techniques,is required.A sediment acoustic survey in the South Yellow Sea from 2009 to 2010 revealed statistical relationships between the in situ sound speed and sediment physical properties.To improve the comparability of these relationships with existing empirical equations,the present study calculated the ratio of the in situ sediment sound speed to the bottom seawater sound speed,and established the relationships between the sound speed ratio and the mean grain size,density and porosity of the sediment.The sound speed of seawater at in situ measurement stations was calculated using a perennially averaged seawater sound speed map by an interpolation method.Moreover,empirical relations between the index of impedance and the sound speed and the physical properties were established.The results confirmed that the existing empirical equations between the in situ sound speed ratio and the density and porosity have general suitability for application.This study also considered that a multiple-parameter equation coupling the sound speed ratio to both the porosity and the mean grain size may be more useful for predicting the sound speed than an equation coupling the sound speed ratio to the mean grain size.

Preparation of IrO_2+MnO_2 coating anodes and their application in NaClO production

To improve the durability as well as to reduce the cost of anodes, the IrO2＋MnO2 composite coating anodes for NaCIO production were prepared by thermal decomposition. Scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDX）, and X-ray diffraction analysis （XRD） were carried out to investigate the morphologies, element distribution, and microstructure. The anodic polarization curves were employed to study the effect of sintering temperature on the Cl2 evolution reaction （CER） of the electrodes. The accelerated life tests （ALT） and electrochemical impedance spectroscopy measurement （EIS） were utilized to investigate the stability. The rules of NaCIO production were also studied by the static electrolysis experiment. The results indicate that sintering temperature has a significant influence on the CER properties as well as the ALT values of the electrodes. The electrode prepared at 400℃ has the best CER properties and the longest ALT value.

Fabrication and Characterization of Yarn-Based Temperature Sensor for Respiratory Monitoring

The development of wearable technologies promotes the research of flexible sensors.It is hoped that a flexible sensor can collect different physiological data,such as temperature and respiratory rate(RR).The temperature of the exhaled gas is generally higher than that in the air,and the periodic change of temperature is related to the respiratory rate.In this work,we use platinum fiber and spandex fiber to prepare yarn-based temperature sensor with high tensile performance through hollow spindle wrapping spinning technology.After the measurement,the sensitivity of the sensor can reach at least 3.18×10^(-3)℃^(-1).We use the sensor and ordinary fabric mask to prepare a sensor mask that can monitor human respiratory signals to explore the performance of the sensor in RR measurement.The experimental results show that when measuring human RR,the yarn-based temperature sensor can accurately distinguish different respiratory states such as normal breathing,deep breathing,and rapid breathing while speaking.It is suggested that yarn-based temperature sensors can be used in medical fields such as real-time respiratory detection and temperature measurement.

Assessment of Respiratory lmpedance During Deep Slow Breathing with lmpulse Oscillometry in Patients with Chronic Obstructive Pulmonary Disease

Objective: To observe the relationship of deep slow respiratory pattern and respiratory impedance(RI) in patients with chronic obstructive pulmonary disease (COPD). Methods: RI under normal respiration and during deep slow respira tion was measured one after the other with impulse oscillometry for 8 patients with COPD and for 9 healthy volunteers as control. Results: When r espiration was changed from normal pattern to the deep slow pattern, the tida l volume increased and respiratory frequency significantly decreased in both gro ups , the total respiratory impedance (Z respir) showed a decreasing trend in COPD group, but with no obvious change in the control group. No chang e in the resonant frequency (fres) was found in both groups, and the respiratory viscous resistance obviously decreased in the COPD group(R5: P =0.0168 ; R20: P =0.0498; R5—R20: P =0.0388),though in the control group it was unchanged. Conclusion: IOS detection could reflect the response he terogeneity of different compartments of respiratory system during tidal breathi ng. During deep slow respiration, the viscous resistance in both central airw ay and peripheral airway was decreased in patients with COPD. RI measurement by impulse oscillometry may be a convenient pathophysiological method for studying the application of breathing exercise in patients with COPD.

RESEARCH ON INPUT IMPEDANCE OF DIPOLE ANTENNA IN GTEM CELL

The formula of input impedance of dipole antenna in Gigahertz Transverse ElectroM agnetic(GTEM) cell based on the dyadic Green's function is first obtained in this paper. The validation of the formula is verified by the results of theoretical derivation and simulation with well agreements. In comparison with the formula of input impedance in free space, the relationship between the change of input impedance with the length of antenna and the position of antenna in GTEM cell is obtained. In addition, some meaningful conclusions are presented, which not only can be referred by the further research of ElectroM agnetic Interference(EMI) measurements in GTEM cell, but also provide the theoretical basis for testing compensation and error analysis.

Nucleation and Growth of Thallium on Thin Film Mercury Electrode: Voltammetric, Scanning Electron Microscopy, Chronoamperometric and Electrochemical Impedance Studies

Thallium is a heavy metal highly toxic to the biosphere. It can be determined by anodic stripping voltammetry after deposition on mercury film. The aim of this work is to study the conditions and mechanisms of deposition of Hg on glassy carbon electrode and Tl on Hg film by cyclic voltammetry, scanning electron microscopy, chronoamperometry and impedance techniques. The results showed a germination and growth of a 3D Hg phase on glassy carbon electrode. Similarly, the electrodeposition of Tl on Hg follows a 3D three-dimensional nucleation with diffusion controlled growth. The impedance measurements reveal an easier charge transfer on the Tl film.

Using the system function to analyze the performance of transducer's impedance measurement method

Prom investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examining the consistency of the transmitting phased array on the single-mode excitation sea spot.In the method based on the system function, the circuit structure of tri-voltage method was used but new parameters were measured.The principle of the method was given first.Then when resistors with different nominal values were used in the circuit,the measured results for the impedance of transducers were reported.The results were compared with the higher precision impedance analyzer.Finally,the error analysis was performed according to the impedance formula and the equivalent circuit parameters were fitted.Under the condition of guaranteeing the sampling precision,by performance analyzing, the resistor value in series was chosen relatively smaller than the impedance of transducer,the measurement of impedance could achieve the same precision as the higher precision impedance analyzer.Finally,the least squares curve-fitting of measured curves indicated that the transducer equivalent electrical parameters could be extracted accurately and used to design the matching network.

Positive predictors for gastroesophageal reflux disease and the therapeutic response to proton-pump inhibitors

AIM: To identify objective and subjective predictors for the reliable diagnosis of gastroesophageal reflux disease (GERD) and the response to proton pump inhibitor (PPI) therapy.

Experimental Evaluation of Transmission Loss of a Glass Cylinder Tube Containing a Fluid

Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified four-microphone standing-wave (impedance) tube for specimens with different lengths, 15 and 30 mm. Each cylinder tube is tested filled with one of the fluids at a time. The fluids are air, water, motor oil and a nanoparticle fluid (in absence of magnetic field). The effects of the cylinder length (thickness), impedance tube terminations, and the containing fluid are discussed. The increasing of the thickness led to an increase of the TL values and a decrease in resonance frequencies. Also, the addition of liquid middle layer led to considerable increase of the TL.

Reconstruction of conductivity distribution of brain tissue from two components magnetic flux density

In this paper the recent Magnetic resonance electrical impedance imaging (MREIT) technique is used to image non-invasively the three-dimensional continuous conductivity distribution of the head tissues. With the feasibility of the human head being rotated twice in the magnetic resonance imaging (MRI) system, a continuous conductivity reconstruction MREIT algorithm based on two components of the measured magnetic flux density is introduced. The reconstructed conductivity image could be obtained through solving iter- atively a non-linear matrix equation. According to the present algorithm of using two magnetic flux den- sity components, numerical simulations were per- formed on a concentric three-sphere and realistic human head model (consisting of the scalp, skull and brain) with the uniform and non-uniform isotropic target conductivity distributions. Based on the algorithm, the reconstruction of scalp and brain conductivity ratios could be figured out even under the condition that only one current is injected into the brain. The present results show that the three-dimensional continuous conductivity reconstruction method with two magnetic flux density components for the realistic head could get better results than the method with only one magnetic flux density component. Given the skull conductivity ratio, the relative errors of scalp and brain conductivity values were reduced to less than 1% with the uniform conductivity distribution and less than 6.5% with the non-uniform distribution for different noise levels. Furthermore, the algorithm also shows fast convergence and improved robustness against noise.

Evaluation of Corrosion Stability of Water Soluble Epoxy-Ester Primer through Electrochemical Studies

The corrosion behavior of water borne epoxy-ester primer coatings (10% - 50% PVCs) was evaluated through electrochemical techniques such as polarization and impedance spectroscopic (EIS) measurements. Studies were carried out for a longer duration of exposure extending up to 60 days in aqueous solution of NaCl (5%). Corrosion current (icorr), Corrosion potential (Ecorr), Coating resistance (Rc), Charge transfer resistance (Rct), Coating capacitance (Cc), Double layer capacitance (Cdl), break point frequency (fb), Water uptake (∮), diffusion coefficient (Dw) etc., indicated that 10% - 30% PVC coatings performed well in comparison to higher PVCs. Changes in the electrochemical characteristics were found to occur as a function of exposure time in all cases. The corrosion stability of the coatings were found to be greatly affected by the percentage of PVCs. Studies further indicated that when lower concentration of pigments were available, they remained completely surrounded by the binder;Thus leaving no space for the entry of corrosive agents. From these studies, it was concluded that the water borne paints could replace the conventional coatings, containing organic solvents. Therefore, water soluble epoxy-ester primers have to be employed in paints for developing eco- friendly coatings.

Laser Deposition of Tetrasulfonated Phthalocyanine Layers for Gas Sensors

Thin layers of nickel and copper tetrasulfonated phthalocyanines (NiPcTS and CuPcTS) were prepared by Matrix Assisted Pulsed Laser Evaporation method. The depositions were carried out with KrF excimer laser (energy density of laser radiation EL = 0.1 to 0.5 J.cm-2) from dimethylsulfoxide matrix. For both materials the ablation threshold EL-th was determined. The following properties of deposited layers were characterized: a) chemical composition (FTIR spectra);b) morphology (SEM and AFM portraits);c) impedance of gas sensors based on NiPcTS and CuPcTS layers in the presence of two analytes - hydrogen and ozone. The prepared sensors exhibit response to 1000 ppm of hydrogen and 100 ppb of ozone even at laboratory temperature.