Health effects and standard threshold shift among workers in a noisy working environment

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.

Dynamic modeling of total ionizing dose-induced threshold voltage shifts in MOS devices

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.

Temporary threshold shift in human subject exposed to noise

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.

Relation between sound transfer function from diffuse sound field to the eardrum and temporary threshold shift

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

The effects of smoking on temporary threshold shift

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.

Migration of weakly bonded oxygen atoms in a-IGZO thin films and the positive shift of threshold voltage in TFTs

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.

Trench型N-Channel MOSFET低剂量率效应研究

基于抗辐射100V Trench型N-Channel MOSFET开展了不同剂量率的总剂量辐射实验并进行了分析,创新性提出了器件随低剂量率累积以及不同偏置状态下的变化趋势和机理,给出了器件实验前后的转移曲线和直流参数,进行了二维数值仿真比较,证明了实验和仿真的一致性。研究表明:随高剂量率的剂量增加,器件阈值电压(V_(TH))发生了明显负向漂移现象,导通电阻(R_(DSON))出现5%左右的降低,击穿电压(BV_(DS))保持基本不变;低剂量率下总剂量效应与高剂量率有明显不同,阈值电压漂移量减小,同时出现正向漂移现象;此时导通电阻(R_(DSON))和击穿电压(BV_(DS))较高剂量率变化量进一步下降。研究认为,低剂量率下器件界面缺陷电荷增加变多,使得阈值电压的漂移方向发生改变,同时低剂量率实验周期是高剂量率的500倍,退火效应也较高剂量率的明显,导致器件参数辐射前后差异性减小。

脉冲对InGaZnO薄膜晶体管性能的影响

超大尺寸IGZO(InGaZnO)产品在高温高湿(50℃/80%)信赖性评价中易发生异常显示不良(Abnormal Display,AD)。其不良原因主要是集成栅极驱动电路(Gate Driver On Array,GOA)的关键器件M2转移特性曲线(IDS-VGS)在评价中发生了严重正移。本文通过脉冲实验,模拟GOA关键器件M2的实际工作环境,重现了转移特性曲线严重正移的不良现象。通过设置不同的脉冲实验,揭示了造成不良的主要影响因素:M2器件关闭时,漏极与源极之间的压差VDS过大,使IGZO膜层内的氧空位V+O在电场作用下同时向IGZO与GI(Gate Insulator)的边界及源极端迁移,由于氧空位V+O对电子的捕获作用,最终导致转移特性曲线发生正移,并发现迁移的氧空位V+O经过加热后可以复原。此外,在不改变IGZO成膜条件下,通过减小M2器件关闭时的VDS压差,导入超大尺寸IGZO产品,高温高湿信赖性评价2000 h未发生AD不良。

保罗·策兰《从门槛到门槛》中的沉默转向

《从门槛到门槛》是保罗·策兰的第二部诗集。在这部诗集中,保罗·策兰的诗歌创作从此开始转向“沉默”。在这部诗集中,策兰有意识地讨论诗歌语言在记录及展现真实历史时的有效性,怀疑诗歌写作的正义性。他的诗歌语言也逐渐趋向破碎,表现出间接、晦涩的特点。策兰诗中的“沉默”书写,通过否定性的表达方式,拓展了对历史真实与诗歌表现关系的思考,深化了德语诗歌对纳粹暴政的反思。

结合Camshift和Kalman预测的运动目标跟踪

针对单一的CamShift跟踪算法在目标发生遮挡时非常容易致使跟踪目标失败的问题,本文提出了一种基于CamShift和Kalman预测的跟踪算法。首先,采用帧间差分阈值法来快速、精确地检测和提取出运动目标;然后,通过在CamShift算法中使用运动目标的颜色特征,在图像序列中找到运动目标的所在位置和大小;最后,使用Kalman滤波预测目标的位置,进而有效地解决了背景中大面积相同颜色的干扰和目标部分被遮挡等问题。用无线遥控车完成了运动目标的跟踪实验,实验证明结合CamShift算法和Kalman预测滤波能实时、准确地跟踪目标。

基于扩展Meanshift电气设备发热故障区域提取方法

在红外电气故障监测中,设备过热故障区通常表现出高亮度等特点,然而现有的提取方法因红外图像固有的低对比度、边界模糊等特点容易引起提取区域范围增大。为此,本文提出了一种基于扩展的均值漂移聚类的红外图像故障过热区域提取方法,引入了基于邻域灰度的权重因子。同时,为了提升聚类效率,摒弃了传统均值漂移算法遍历整个红外图像平面进行迭代聚类的方法,融合了自高向低的聚类阈值分割机制,使得改进的均值漂移算法能快速地将故障区域像素进行聚类,实现红外图像中热故障区域的有效提取。实验结果表明本文区域提取性能优于目前现有的一些方法以及传统均值漂移聚类方法。

基于自适应尺度的Mean-shift跟踪算法

针对传统Mean-shift跟踪算法不能解决目标跟踪中的目标特征大小变化问题,在此通过对Mean-shift算法的深入研究,提出了基于自适应尺度的Mean-shift目标跟踪算法。通过引用尺度空间理论,改变尺度空间中的选择参数,调整追踪窗口的大小来解决跟踪时自适应目标大小特征变化的问题。计算机仿真实验表明,基于自适应尺度的Mean-shift跟踪算法的跟踪所取得的效果明显优于传统方法的目标跟踪方法。

Weighted Self-Adaptive Threshold Wavelets for Interpolation Point Selection Used in Interconnect MOR

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.

PTEN inhibitor bisperoxovanadium protects against noise-induced hearing loss

Studies have shown that phosphatase and tensin homolog deleted on chromosome ten(PTEN)participates in the regulation of cochlear hair cell survival.Bisperoxovanadium protects against neurodegeneration by inhibiting PTEN expression.However,whether bisperoxovanadium can protect against noise-induced hearing loss and the underlying mechanism remains unclear.In this study,we established a mouse model of noise-induced hearing loss by exposure to 105 dB sound for 2 hours.We found that PTEN expression was increased in the organ of Corti,including outer hair cells,inner hair cells,and lateral wall tissues.Intraperitoneal administration of bisperoxovanadium decreased the auditory threshold and the loss of cochlear hair cells and inner hair cell ribbons.In addition,noise exposure decreased p-PI3K and p-Akt levels.Bisperoxovanadium preconditioning or PTEN knockdown upregulated the activity of PI3K-Akt.Bisperoxovanadium also prevented H_(2)O_(2)-induced hair cell death by reducing mitochondrial reactive oxygen species generation in cochlear explants.These findings suggest that bisperoxovanadium reduces noise-induced hearing injury and reduces cochlear hair cell loss.

Effects of 946-nm thermal shift and broadening on Nd^(3+):YAG laser performance

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.

Identification of Global Gene Expression Shifts Using Microarray Data from Different Biological Conditions

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.

基于Mean Shift的芯片X光图像层次分割算法

针对芯片X光图像多目标、背景复杂、灰度分布不均匀的特点,提出一种基于Mean Shift的层次分割算法。运用旋转缩放不变的模板匹配定位算法定位芯片并确定其兴趣区域(ROI),从而实现外层分割。再运用Mean Shift算法对芯片模板图像和芯片ROI图像进行统计聚类分析,分别计算原图像金线模式类的灰度平均值,以芯片模板图像的金线模式类的平均灰度为基准,对芯片ROI的聚类图像采用优化阈值进行自适应阈值分割,从而实现内层分割。实验结果表明:与传统的均值偏移分割算法相比,该方法的多目标分割准确,可靠性高。

30V SGT N-Channel MOSFET总剂量效应研究

对30V SGT型N-Channel MOSFET进行了两种不同偏置的总剂量辐射实验,随着^(60)Coγ源射线剂量的增加,给出了两种偏置状态下器件实验前后的转移曲线和直流参数变化,揭示了SGT型功率器件随剂量和偏置的变化趋势和机理。研究结果表明,随着总剂量的增加,两种偏置下器件的阈值电压、导通电阻和击穿电压均出现下降的情况。不同之处是OFF态下主要参数发生变化的幅度收窄,下降幅度相对较小。同时,出现了击穿电压先增加后下降的现象,分析认为,在^(60)Coγ源射线的作用下器件沟槽栅极下方的多晶硅屏蔽栅极存在比较厚的氧化层,在低剂量时元胞和终端处的厚氧化层产生总剂量效应,使得SGT型功率器件发生局部场强改变,从而出现该变化。

广义S变换和阈值分割联合抗频谱扩展-压缩移频干扰

根据频谱扩展-压缩(spectrum spread and compression,SSC)移频干扰信号和回波信号时频分布特性的差异,提出一种基于广义S变换和Tsallis交叉熵阈值分割的干扰抑制方法。分析了SSC移频干扰的干扰原理和干扰信号经过解线调后的信号形式,并利用时频聚焦性较好的广义S变换获取接收信号经过解线调后的时频图像,根据时频图像对应的灰度图像,以Tsallis交叉熵最小化作为目标函数,求出灰度图像的最佳分割阈值,并根据分割阈值构建时频滤波器,实现干扰抑制。仿真结果表明:该方法对于SSC移频干扰产生的假目标具有较好的抑制效果,干扰抑制比可达30 dB以上。

基于IGZO薄膜晶体管的高可靠性时分驱动GOA电路

本文提出一种新颖的基于IGZO(Indium Gallium Zinc Oxide)薄膜晶体管的双向扫描集成栅极驱动(Gate Driver on Array,GOA)电路,特别适用于in-cell触控显示.本文提出的GOA电路采用时分驱动方式(Time-Division Driving Method,TDDM)实现高报点率的in-cell触控,并防止触控信号失真.该GOA电路支持扫描-暂停-重启模式,即输出几十个连续的显示寻址扫描脉冲后,栅极驱动输出暂停以执行触控侦测.在触控侦测期间,GOA电路中的Touch控制单元开始工作,使所有栅极输出低电位以消除显示驱动信号对触控的干扰.此外,本文提出的GOA电路采用双低电平维持(Low Level Maintaining,LLM)模块,能有效抑制LLM晶体管的阈值电压漂移.电学模拟结果表明,本文提出的GOA电路无论工作于正向还是反向扫描,均能产生均匀的输出波形,并且停坑级的输出波形与正常级波形一致.采用IGZO晶体管制作了10.4英寸in-cell触控显示面板以验证本文提出的GOA电路,支持90 Hz显示刷新率与180 Hz触控报点率.此外,借助工艺与设计优化,进一步提高GOA电路在恶劣环境下的使用寿命,成功通过高温高湿(85℃/85%)操作500 h的可靠性测试.