Papers by Keyword: Sensitivity

Abstract: The Cu/Ni thin film as low-temperature sensor was produced by electroplating on the various deposition times assisted with a 200G magnetic field in the transverse direction to the surface of Cu. The deposition time was varied from 0 to 45s. The liquid nitrogen (LN2) 0°C to -200°C was used as a tested low-temperature medium. The characterization was done on the voltage range and sensitivity. Cu/Ni sensor from deposition within 25s has the largest voltage range that is 128.48 mV and has the sensitivity (S) that has a linear relationship with temperature (T) according to S(T) = 0.287 - 0.002T.

Abstract: The influence of different acidic medium, including hydrochloric acid, nitric acid and perchloric acid on the absorbance of sodium by flame atomic absorption spectrometry was studied. The results showed that the effects of acidic medium and water on the determination of sodium were as follows: hydrochloric acid > perchloric acid > nitric acid > water. Acid effect changed with the increase of acid concentration, however, the absorbance value of sodium element decreased when the concentration of acid was higher than 1%~2%. This effect was more obvious for high content of sodium. The detection limits, repeatability and recovery of the samples under the three acidic medium were compared. The optimum acid conditions were determined and the sensitivity of the method was improved.

Abstract: The development of highly selective and sensitive surface plasmon resonance (SPR) immunoassay for the rapid detection of illegal compound using secondary antibody interaction labelled nanoparticle was conducted. For the construction of SPR sensor surface, the illegal compound (clenbuterol) was immobilized as antigen onto gold succinimide-terminated monolayer to perform amide-coupling reaction. In order to avoid non-specific reaction, the blocking agent (ethanol amine) was injected to the SPR system. Furthermore, indirect competitive inhibition method was employed in the detection of clenbuterol. In this work, the antibody solution (PBS solution containing clenbuterol antibody) premixed with a sample solution (PBS solution containing antigen) before the injection into the sensing system. As the premixed solution flowed over the sensor surface, the SPR senses the dielectric constant change at the interface due to the binding of the unreacted primary antibody to antigen-immobilized on the sensor surface. After this primary antibody detection, secondary antibody was injected to the SPR sensor surface. Here, we compared the signal difference of secondary antibody injection labelled Au nanoparticles (d = 40 nm). For the regeneration of the sensor surface, 0.1 M NaOH was used, so primary and secondary antibodies could be detached from the sensor surface. According to the indirect competitive inhibition method, it was found that the sensitivity for clenbuterol detection was enhanced from 2.5 ppt to 0.07 ppt.

Abstract: In present work, two types of Interferometric Fiber Optic Sensor (Fabry – Perot & Modal Sensor) have been demonstrate and investigated. The main parameter studied of this contribute is the sensitivity, the strain could be induced by make a stress on the optical fiber. The strain effect at the fiber due to variation of the intensity in the output of the optical fiber. Then, the modes of electromagnetic waves that propagate in the fiber could be analyzed to determine the sensitivity depend on fringe rates. I conclude from this study the Extrinsic Fabry – Perot Interferometry structure is more sensitive than Modal Sensor.

Abstract: This study aimed to determine the ammonia (NH₃) gas sensing ability of zinc oxide (ZnO) films deposited on glass tube substrates via successive ionic layer adsorption and reaction (SILAR) technique. The fabricated films were annealed at different temperatures. The sensor films were exposed to different volumes of ammonium hydroxide (NH₄OH), converted to parts per million (ppm). The change in voltage from concentrations 595ppm up to 1189ppm exhibited a linear trend. However, no trend was revealed in concentrations 2378ppm and 3964ppm due to film saturation. Results showed that the films annealed at 250 °C, 300 °C, 350 °C, and 400 °C presented sensitivities of 2.7×10^-4 V/ppm, 1.0×10^-4 V/ppm, 2.3×10^-4 V/ppm, and 1.5×10^-4 V/ppm with R² values of 0.997, 0.994, 0.904, 0.999 and resolutions of 3.7 ppm/mV, 9.9 ppm/mV, 4.4 ppm/mV, and 6.6 ppm/mV, respectively. Furthermore, this research study had proven that high quality gas sensors may be fabricated at a lower cost.

Abstract: Considering the traditional safety factor method of reliability design can’t well reflect the uncertainty of loads, and error is obvious by using the tension of the wire rope represents the stress state of the hoist drum web plate. Established stress model of the dangerous section of the hoist drum web plate. Deduced reliability index and reliability by using stress & strength interference theory and perturbation method. Sensitivity analysis and robust optimal design was performed on this basis. The results show that the strain on the hoist drum web plate has a great influence on reliability of itself, and the reliability robust optimization design information can be obtained by using strain on web plate and reliability as optimization objectives. These not only provide the theoretical basis for the safety maintenance and design of the hoist, but also have the practical application value for reliable and efficient delivery of hoist.

Abstract: Quasi-static absolute calibration is using force with semi-sinusoidal pulse to calibrate pressure measuring system. The pulse width must be wide enough in order to guarantee the effective bandwidth of frequency spectrum be in the flat section of amplitude-frequency characteristics of the tested system. In this way, the result is similar to that from static calibration. The working characteristic parameters for measuring system which is gained from quasi-static calibration is different form static calibration in species, physical meanings and attainment methods. Therefore, the research is of great significance in forming quasi-static calibration system and improving measurement accuracy. The pilot scheme will be introduced in this essay. What is more, the calculation of working characteristic parameters for measuring system will be discussed by taking the force with specific pulse as example, including sensitivity when force transfer to pressure, linearity and repeatability which are used to evaluate the uncertainty of measurement.

Abstract: There is increasing interest in the development of radiation hard detector materials with the capability to discriminate within wide dose range and high radiation tolerance that are sensitive, and show a linear response. In this study, fabricated 4H-SiC Schottky diodes were exposed to dose rates ranging from 0.02 to 0.185 mGy/min to analyse the linearity and sensitivity at room temperature. High linearity response presented from the graph of current signal plotted versus dose rate which show enhancement of 10⁴ in comparison to previous studies. The sensitivity measured at different bias voltages by exposing to 0.185 mGy/min dose rate show good reproducibility and stability of the current signal with time. Collected charge presented for all diodes exhibit linear behaviour of photon induced collected charge with the sensitivity between 1.40 to 8.38 x 10⁵ nC/Gy for the 0.20 to 1 mGy absorbed dose range. Thus, these devices are ideally suited for the realisation of radiation detectors at moderate dose range.

Abstract: To explore effects of air humidity on properties of JO-9159 explosive, the amorphous model of six components was constructed by Materials Studio software, periodic molecular dynamics simulation was conducted at seven kinds of relative humidity ranging from 10% to 70% for (001), (010), (100) crystal planes of JO-9159 explosive in COMPASS force field and NVT ensemble. Mechanical properties, sensitivity and detonation properties of JO-9159 explosive were researched basing on equilibrium trajectory of model. The results show that with the increasing of relative humidity, the total adsorption energy increases. The adsorption capacity of JO-9159 explosive for H₂O is much stronger than O₂ and N₂; The breaking strength has a decreasing trend with the humidity increases and the stiffness and hardness of JO-9159 explosive are smaller at 30% and 40% relative humidity; At 30% relative humidity, the sensitivity of JO-9159 explosive is highest and detonation properties are weakest, while the detonation properties are strongest at 20% relative humidity.

Abstract: The paper deals with the upper and lower limits estimation of the friction work and fretting wear in the contact of nuclear fuel rods with fuel assembly (FA) spacer grid cells. The friction work is deciding factor for the prediction of the fuel rod cladding abrasion caused by FA vibration. Design and operational parameters of the FA components are understood as random variables defined by mean values and standard deviations. The gradient and three sigma criterion approach is applied to the calculation of the upper and lower limits of the friction work and fretting wear in particular contact surfaces between the fuel rod cladding and some of spacer grid cells. The fuel assembly vibration is excited by pressure pulsations of the cooling liquid generated by main circulation pumps in the coolant loops of the NPP primary circuit. The method is applied for hexagonal type nuclear fuel assembly in the VVER type reactors.