Introduction: Working in a noisy environment is a risk for employee hearing health. Standard threshold shift (STS) can be used as a screening method to detect early indications of hearing deterioration. Objective: To ...Introduction: Working in a noisy environment is a risk for employee hearing health. Standard threshold shift (STS) can be used as a screening method to detect early indications of hearing deterioration. Objective: To investigate health effects related to STS in motor compressor workers. Methods: A cross sectional study of 464 motor compressor workers was conducted including hearing health examination by audiometer, and noise level in the workplace was monitored. Workers who reported having hobbies relating to noise, e.g. gun shooting, or a personal history of disease relating to the ear were excluded. The relationship between health effects and workers with STS was studied. Results: There were more men 81.90% (aged range 31-40 years old) than women working for the company. The average continuous noise level in the workplace was 84.14 ± 5.21 dB(A). The study showed that working at the factory for more than 14 years (OR= 3.84, 95%CI 1.54-9.56) and being exposed to noise at least 8 hours a day (OR = 2.12, 95%CI = 1.02-4.40) effected to STS. Workers with STS showed significant communication difficulties (OR = 1.89, 95%CI = 1.03-3.49) and stress/nausea more than workers without STS (OR = 1.54, 95%CI = 0.90-2.65) although not statistically significant. Conclusions: Workers exposed to continuous noise in the motor compressor industry are at risk of STS. Duration of exposure to noise is a key factor in respect of harm to hearing health. STS could be used as a tool to screen workers who have hearing health problems.展开更多
Using an audiometer, the effect of the noise level upon temporary threshold shift (TTS) for five trained normal subjects (left ear only) was studied. The measurements were carried out after 6 min exposure (in third oc...Using an audiometer, the effect of the noise level upon temporary threshold shift (TTS) for five trained normal subjects (left ear only) was studied. The measurements were carried out after 6 min exposure (in third octave band) for different sound pressure levels ranging between 75-105 dB at three test frequencies 2,3, and 4 kHz. The results indicated that at exposure to noise of sound pressure level (SPL) above 85 dB, TTS increases linearly with ths SPL for all the test frequencies. The work had extended to study the recovery curves for the same ears. The results indicated that the reduction in TTS on doubling the recovery times, for the two sound pressure levels 95 dB and 105 dB, occurs at a rate of nearly 3 dB. The comparison of the recovery curve at 3 kHz with that calculated using Ward's general equation for recovery was made. Finally, to study the values of TTS produced by exposure to certain noise at different test frequencies, distribution curves for two recovery times were plotted representing TTS values, for an exposure noise of 1 / 3 octave band and centre frequency 2 kHz, at different test frequencies.展开更多
Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated...Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated to the temporary threshold shift (TTS) due to fiffuse-exposure.A probe tube with a miniature microphone was used for STF measurements in which successive 1/3 oct bandwidth random noise with central frequency from 0.25 kKz to 8 kHz were used. The subjects were divided into two groups, with the STF maxima at 2 kHz and 4 kHz respectively Pre- and post- exposure sweep Bekesy audiograms were recorded and the temporary thresh old shift calctilated as the difference between the two. Frequency of the maximum TTS was correlated to that of the maximum STF. The average TTS was very small or zero at frequen cies below the band noise exposure , but was noticeable even at the highest measured frequency (8 kHz) for beyond the noise band. Also individual differences in STF were found at frequencies between 2 kHz and 4 kHz展开更多
For studying the influence of smoking on temporary threshold shift (TTS), six normal subjects (3 smokers and 3 nonsmokers) were selected for carrying out this work. Nonsmokers were exposed separately for 7 min to 95 ...For studying the influence of smoking on temporary threshold shift (TTS), six normal subjects (3 smokers and 3 nonsmokers) were selected for carrying out this work. Nonsmokers were exposed separately for 7 min to 95 dB SPL in 1/3-octave band filtered noise centred at 2 kHz. Pre and post exposure thresholds (leftear) were recorded in a sound-proof booth using Bruel & Kjaer (B & K) Audiometer type 1800. For smokers, each one smoked a cigarette during the five minutes following the pre-exposure threshold measurement. All the assessments were conducted at a temperature between 22-25℃. The results indicated that smokers evidenced less TTS than did nonsmokers in the frequency range from 1 kHz to 5 kHz. At 6 kHz smokers evidenced nearly higher value. Maximum TTS was attained at frequency that was about 1/2-octave higher than that of the exposed noise. Comparison between recovery curves for smokers and nonsmokers was also made.展开更多
The total ionizing dose(TID) effect is a key cause for the degradation/failure of semiconductor device performance under energetic-particle irradiation. We developed a dynamic model of mobile particles and defects by ...The total ionizing dose(TID) effect is a key cause for the degradation/failure of semiconductor device performance under energetic-particle irradiation. We developed a dynamic model of mobile particles and defects by solving the rate equations and Poisson's equation simultaneously, to understand threshold voltage shifts induced by TID in silicon-based metal–oxide–semiconductor(MOS) devices. The calculated charged defect distribution and corresponding electric field under different TIDs are consistent with experiments. TID changes the electric field at the Si/SiO_(2) interface by inducing the accumulation of oxide charged defects nearby, thus shifting the threshold voltage accordingly. With increasing TID, the oxide charged defects increase to saturation, and the electric field increases following the universal 2/3 power law. Through analyzing the influence of TID on the interfacial electric field by different factors, we recommend that the radiation-hardened performance of devices can be improved by choosing a thin oxide layer with high permittivity and under high gate voltages.展开更多
Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly b...Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly bonded oxygen(O)atoms exist in a-IGZO thin films deposited at high O_(2) pressures,but these can be eliminated by vacuum annealing.The threshold voltage(V_(th))of the a-IGZO TFTs is shifted under positive gate bias,and the Vth shift is positively related to the deposition pressure.A temperature variation experiment in the range of 20 K-300 K demonstrates that an activation energy of 144 meV is required for the Vth shift,which is close to the activation energy required for the migration of weakly bonded O atoms in a-IGZO thin films.Accordingly,the Vth shift is attributed to the acceptor-like states induced by the accumulation of weakly bonded O atoms at the a-IGZO/SiO_(2) interface under positive gate bias.These results provide an insight into the mechanism responsible for the Vth shift of the a-IGZO TFTs and help in the production of reliable designs.展开更多
As process technology development,model order reduction( MOR) has been regarded as a useful tool in analysis of on-chip interconnects. We propose a weighted self-adaptive threshold wavelet interpolation MOR method on ...As process technology development,model order reduction( MOR) has been regarded as a useful tool in analysis of on-chip interconnects. We propose a weighted self-adaptive threshold wavelet interpolation MOR method on account of Krylov subspace techniques. The interpolation points are selected by Haar wavelet using weighted self-adaptive threshold methods dynamically. Through the analyses of different types of circuits in very large scale integration( VLSI),the results show that the method proposed in this paper can be more accurate and efficient than Krylov subspace method of multi-shift expansion point using Haar wavelet that are no weighted self-adaptive threshold application in interest frequency range,and more accurate than Krylov subspace method of multi-shift expansion point based on the uniform interpolation point.展开更多
Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission wit...Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.展开更多
Gene expression data have been very useful during the past two decades for the detection of differentially expressed genes when two (or more) biological conditions are compared. Studies seeking for differentially expr...Gene expression data have been very useful during the past two decades for the detection of differentially expressed genes when two (or more) biological conditions are compared. Studies seeking for differentially expressed genes are based on testing gene by gene for a mean differential expression between two conditions. Nevertheless, the global shift in gene expression when taking into account all genes present on a microarray experiment, has not yet been investigated and could provide different information on genes that could be affected by the condition under research. Such a global approach would help identifying a gene expression threshold, characteristic of a certain condition and therefore could be used for diagnosis together with the list of differentially expressed genes detected by classical methods. Moreover, characterizing genes below or above such a threshold could give new insights into the molecular mechanisms implicated functionally in each condition. Here, we present a simple methodology, based on heuristics, gene filtering, variable transformation and descriptive statistics in order to identify such global gene expression shifts and the characteristic threshold so the same can be applied by any professional that works with expression gene data and not only by statisticians. Our procedure is illustrated on a real gene expression data set comparing pathogen inoculated tomatoes with non-inoculated tomatoes. This methodology can be used for the identification of the threshold values when we have continuous variable data sets from two populations with overlapped distributional forms (histograms) in most of their percentiles.展开更多
Irradiation experiments on p-Ga N gate high-electron-mobility transistors(HEMTs) were conducted using neutrons at Back-streaming White Neutron(Back-n) facility at the China Spallation Neutron Source(CSNS).Two groups o...Irradiation experiments on p-Ga N gate high-electron-mobility transistors(HEMTs) were conducted using neutrons at Back-streaming White Neutron(Back-n) facility at the China Spallation Neutron Source(CSNS).Two groups of devices were float-biased,while one group was ON-biased.Post-irradiation analysis revealed that the electrical performance of the devices exhibited progressive degradation with increasing Back-n fluence,with the ON-biased group demonstrating the most pronounced deterioration.This degradation was primarily characterized by a negative shift in the threshold voltage,a significant increase in reverse gate leakage current,and a slight reduction in forward gate leakage.Further analysis of the gate leakage current and capacitance-voltage characteristics indicated an elevated concentration of two-dimensional electron gas(2DEG),attributed to donor-type defects introduced within the barrier layer by Back-n irradiation.These defects act as hole traps,converting into fixed positive charges that deepen the quantum-well conduction band,thereby enhancing the 2DEG density.Additionally,through the trap-assisted tunneling mechanism,these defects serve as tunneling centers,increasing the probability of electron tunneling and consequently elevating the reverse gate leakage current.展开更多
文摘Introduction: Working in a noisy environment is a risk for employee hearing health. Standard threshold shift (STS) can be used as a screening method to detect early indications of hearing deterioration. Objective: To investigate health effects related to STS in motor compressor workers. Methods: A cross sectional study of 464 motor compressor workers was conducted including hearing health examination by audiometer, and noise level in the workplace was monitored. Workers who reported having hobbies relating to noise, e.g. gun shooting, or a personal history of disease relating to the ear were excluded. The relationship between health effects and workers with STS was studied. Results: There were more men 81.90% (aged range 31-40 years old) than women working for the company. The average continuous noise level in the workplace was 84.14 ± 5.21 dB(A). The study showed that working at the factory for more than 14 years (OR= 3.84, 95%CI 1.54-9.56) and being exposed to noise at least 8 hours a day (OR = 2.12, 95%CI = 1.02-4.40) effected to STS. Workers with STS showed significant communication difficulties (OR = 1.89, 95%CI = 1.03-3.49) and stress/nausea more than workers without STS (OR = 1.54, 95%CI = 0.90-2.65) although not statistically significant. Conclusions: Workers exposed to continuous noise in the motor compressor industry are at risk of STS. Duration of exposure to noise is a key factor in respect of harm to hearing health. STS could be used as a tool to screen workers who have hearing health problems.
文摘Using an audiometer, the effect of the noise level upon temporary threshold shift (TTS) for five trained normal subjects (left ear only) was studied. The measurements were carried out after 6 min exposure (in third octave band) for different sound pressure levels ranging between 75-105 dB at three test frequencies 2,3, and 4 kHz. The results indicated that at exposure to noise of sound pressure level (SPL) above 85 dB, TTS increases linearly with ths SPL for all the test frequencies. The work had extended to study the recovery curves for the same ears. The results indicated that the reduction in TTS on doubling the recovery times, for the two sound pressure levels 95 dB and 105 dB, occurs at a rate of nearly 3 dB. The comparison of the recovery curve at 3 kHz with that calculated using Ward's general equation for recovery was made. Finally, to study the values of TTS produced by exposure to certain noise at different test frequencies, distribution curves for two recovery times were plotted representing TTS values, for an exposure noise of 1 / 3 octave band and centre frequency 2 kHz, at different test frequencies.
文摘Twelve volunteers with normal hearing (9 males and 3 females) participated in this work The sound transfer functions (STFS) from diffuse sound field to the subject's eardrums were measured and correlated to the temporary threshold shift (TTS) due to fiffuse-exposure.A probe tube with a miniature microphone was used for STF measurements in which successive 1/3 oct bandwidth random noise with central frequency from 0.25 kKz to 8 kHz were used. The subjects were divided into two groups, with the STF maxima at 2 kHz and 4 kHz respectively Pre- and post- exposure sweep Bekesy audiograms were recorded and the temporary thresh old shift calctilated as the difference between the two. Frequency of the maximum TTS was correlated to that of the maximum STF. The average TTS was very small or zero at frequen cies below the band noise exposure , but was noticeable even at the highest measured frequency (8 kHz) for beyond the noise band. Also individual differences in STF were found at frequencies between 2 kHz and 4 kHz
文摘For studying the influence of smoking on temporary threshold shift (TTS), six normal subjects (3 smokers and 3 nonsmokers) were selected for carrying out this work. Nonsmokers were exposed separately for 7 min to 95 dB SPL in 1/3-octave band filtered noise centred at 2 kHz. Pre and post exposure thresholds (leftear) were recorded in a sound-proof booth using Bruel & Kjaer (B & K) Audiometer type 1800. For smokers, each one smoked a cigarette during the five minutes following the pre-exposure threshold measurement. All the assessments were conducted at a temperature between 22-25℃. The results indicated that smokers evidenced less TTS than did nonsmokers in the frequency range from 1 kHz to 5 kHz. At 6 kHz smokers evidenced nearly higher value. Maximum TTS was attained at frequency that was about 1/2-octave higher than that of the exposed noise. Comparison between recovery curves for smokers and nonsmokers was also made.
基金Project supported by the Science Challenge Project of China (Grant No.TZ2018004)the National Natural Science Foundation of China (Grant Nos.11975018 and 11775254)+1 种基金the National MCF Energy R&D Program of China (Grant No.2018YEF0308100)the outstanding member of Youth Innovation Promotion Association CAS (Grant No.Y202087)。
文摘The total ionizing dose(TID) effect is a key cause for the degradation/failure of semiconductor device performance under energetic-particle irradiation. We developed a dynamic model of mobile particles and defects by solving the rate equations and Poisson's equation simultaneously, to understand threshold voltage shifts induced by TID in silicon-based metal–oxide–semiconductor(MOS) devices. The calculated charged defect distribution and corresponding electric field under different TIDs are consistent with experiments. TID changes the electric field at the Si/SiO_(2) interface by inducing the accumulation of oxide charged defects nearby, thus shifting the threshold voltage accordingly. With increasing TID, the oxide charged defects increase to saturation, and the electric field increases following the universal 2/3 power law. Through analyzing the influence of TID on the interfacial electric field by different factors, we recommend that the radiation-hardened performance of devices can be improved by choosing a thin oxide layer with high permittivity and under high gate voltages.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51771144 and 62104189)the Natural Science Foundation of Shaanxi Province,China(Grant Nos.2021JC-06,2019TD-020,and 2019JLM-30)+1 种基金the China Postdoctoral Science Foundation(Grant No.2020M683483)the Fundamental scientific research business expenses of Xi'an Jiaotong University(Grant No.XZY022020017).
文摘Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly bonded oxygen(O)atoms exist in a-IGZO thin films deposited at high O_(2) pressures,but these can be eliminated by vacuum annealing.The threshold voltage(V_(th))of the a-IGZO TFTs is shifted under positive gate bias,and the Vth shift is positively related to the deposition pressure.A temperature variation experiment in the range of 20 K-300 K demonstrates that an activation energy of 144 meV is required for the Vth shift,which is close to the activation energy required for the migration of weakly bonded O atoms in a-IGZO thin films.Accordingly,the Vth shift is attributed to the acceptor-like states induced by the accumulation of weakly bonded O atoms at the a-IGZO/SiO_(2) interface under positive gate bias.These results provide an insight into the mechanism responsible for the Vth shift of the a-IGZO TFTs and help in the production of reliable designs.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2016107)the China Postdoctoral Science Foundation(Grant No.2015M581447)
文摘As process technology development,model order reduction( MOR) has been regarded as a useful tool in analysis of on-chip interconnects. We propose a weighted self-adaptive threshold wavelet interpolation MOR method on account of Krylov subspace techniques. The interpolation points are selected by Haar wavelet using weighted self-adaptive threshold methods dynamically. Through the analyses of different types of circuits in very large scale integration( VLSI),the results show that the method proposed in this paper can be more accurate and efficient than Krylov subspace method of multi-shift expansion point using Haar wavelet that are no weighted self-adaptive threshold application in interest frequency range,and more accurate than Krylov subspace method of multi-shift expansion point based on the uniform interpolation point.
基金Project supported by Estahban Branch,Islamic Azad University
文摘Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.
文摘Gene expression data have been very useful during the past two decades for the detection of differentially expressed genes when two (or more) biological conditions are compared. Studies seeking for differentially expressed genes are based on testing gene by gene for a mean differential expression between two conditions. Nevertheless, the global shift in gene expression when taking into account all genes present on a microarray experiment, has not yet been investigated and could provide different information on genes that could be affected by the condition under research. Such a global approach would help identifying a gene expression threshold, characteristic of a certain condition and therefore could be used for diagnosis together with the list of differentially expressed genes detected by classical methods. Moreover, characterizing genes below or above such a threshold could give new insights into the molecular mechanisms implicated functionally in each condition. Here, we present a simple methodology, based on heuristics, gene filtering, variable transformation and descriptive statistics in order to identify such global gene expression shifts and the characteristic threshold so the same can be applied by any professional that works with expression gene data and not only by statisticians. Our procedure is illustrated on a real gene expression data set comparing pathogen inoculated tomatoes with non-inoculated tomatoes. This methodology can be used for the identification of the threshold values when we have continuous variable data sets from two populations with overlapped distributional forms (histograms) in most of their percentiles.
基金supported by the National Natural Science Foundation of China (Grant Nos.12120101005,U2030104,12175174,11975174,and 12105229)State Key Laboratory Foundation of Laser Interaction with Matter (Grant Nos.SKLLIM1807 and SKLLIM2106)+1 种基金the Postdoctoral Fellowship Program of CPSF (Grant No.GZC20241372)National Key Laboratory of Intense Pulsed Radiation Simulation and Effect (Grant No.NKLIPR2419)。
文摘Irradiation experiments on p-Ga N gate high-electron-mobility transistors(HEMTs) were conducted using neutrons at Back-streaming White Neutron(Back-n) facility at the China Spallation Neutron Source(CSNS).Two groups of devices were float-biased,while one group was ON-biased.Post-irradiation analysis revealed that the electrical performance of the devices exhibited progressive degradation with increasing Back-n fluence,with the ON-biased group demonstrating the most pronounced deterioration.This degradation was primarily characterized by a negative shift in the threshold voltage,a significant increase in reverse gate leakage current,and a slight reduction in forward gate leakage.Further analysis of the gate leakage current and capacitance-voltage characteristics indicated an elevated concentration of two-dimensional electron gas(2DEG),attributed to donor-type defects introduced within the barrier layer by Back-n irradiation.These defects act as hole traps,converting into fixed positive charges that deepen the quantum-well conduction band,thereby enhancing the 2DEG density.Additionally,through the trap-assisted tunneling mechanism,these defects serve as tunneling centers,increasing the probability of electron tunneling and consequently elevating the reverse gate leakage current.
