【正文】 st China39。 names and figuring out what to do with them for the brief time each week that I stand in front of them. I do not consider the challenges of learning to live here part of a purposeful life. I consider those issues existential in nature. One of the problems with my life in America was that I felt it had no purpose. I went to work every day and even did what I could to make my colleagues39。t just about sharing art with nomadic families but also about gaining inspiration for the music and dance. Ulan Muqir literally translates as red burgeon, and today39。 ② 耳塞在應(yīng)用過(guò)程中可能存在一個(gè)保護(hù)率的問(wèn)題 ③ 由于本實(shí)驗(yàn)方法比較新 穎，在之前的研究中未被提及，在設(shè)計(jì)、實(shí)施和計(jì)算過(guò)程中有些地方還不夠準(zhǔn)確和完善。 ＜ 3 177。 質(zhì)量控制 設(shè)計(jì)階段 查閱文獻(xiàn)，合理設(shè)計(jì)測(cè)試方案，在正式測(cè)試前進(jìn)行預(yù)實(shí)驗(yàn)，及時(shí)發(fā)現(xiàn)和解決測(cè)試過(guò)程中可能出現(xiàn)的問(wèn)題。并且在現(xiàn)場(chǎng)噪聲環(huán)境中，耳塞的實(shí)際聲衰值與實(shí)驗(yàn)室測(cè)試結(jié)果有一定的差距 [12] ，因此本課題擬采用純音氣導(dǎo)聽(tīng)閾測(cè)聽(tīng)法對(duì)受試者佩戴護(hù)耳器前后的聽(tīng)閾進(jìn)行測(cè)量，計(jì)算每種護(hù)耳器的實(shí)際 A 聲級(jí)降噪值，對(duì)護(hù)耳器的實(shí)際降噪效果進(jìn)行評(píng)價(jià)，可以為建設(shè)項(xiàng)目職業(yè)病危害評(píng)價(jià)中護(hù)耳器的防護(hù)效果評(píng)價(jià)和企業(yè)護(hù)耳器選用 提供有益的參考。 A levels noise reduction 目 錄 Ⅲ 目 錄 摘 要 .............................................................. I ABSTRACT........................................................... II 目 錄 ......................................................... III 1 前 言 ............................................................. 1 2 對(duì)象與方法 ........................................................ 3 研究?jī)?nèi)容 ...................................................... 3 研究對(duì)象 ...................................................... 3 耳塞的選取 .................................................... 3 耳塞概況 .................................................. 3 耳塞形狀 .................................................. 4 測(cè)試條件 ...................................................... 5 測(cè)試方法 ...................................................... 5 測(cè)試步驟 ...................................................... 5 數(shù)據(jù)記錄 ...................................................... 6 統(tǒng)計(jì)學(xué)分析 .................................................... 6 質(zhì)量控制 ...................................................... 6 設(shè)計(jì)階段 .................................................. 6 實(shí)施階段 .................................................. 6 資料的整理與分析 .......................................... 7 3 結(jié)果 .............................................................. 8 6 種耳塞的實(shí)際 A 聲級(jí)降噪值 .................................... 8 耳塞的實(shí)際降噪值與估計(jì)降噪值之間的差異性分析 .................. 9 耳塞的實(shí)際降噪值與 SNR、 NRR 值之間的關(guān)聯(lián)性分析 ................. 9 4 討論 ............................................................. 12 5 結(jié)論 ............................................................. 14 參考文獻(xiàn) ........................................................... 15 英文縮略語(yǔ) ......................................................... 16 謝 辭 ............................................................. 17 前言 1 1 前 言 噪聲一般指環(huán)境中不需要且會(huì)使人感到厭煩的一切聲音 ,在世界范圍內(nèi)，生產(chǎn)性噪聲已經(jīng)成為嚴(yán)重危害勞動(dòng)者健康的職業(yè)危害因素之一。我國(guó)目前生產(chǎn)過(guò)程中接觸噪聲的人數(shù)多，涉及行業(yè)廣，如化工廠的空氣壓縮機(jī)、鼓風(fēng)機(jī)和鍋爐排氣放空時(shí)產(chǎn)生的噪聲，水泥加工廠球磨機(jī)、粉碎機(jī)工作時(shí)產(chǎn)生的噪聲，煤礦行業(yè)采煤、掘進(jìn)、運(yùn)輸、提升、排風(fēng)等作業(yè)時(shí)產(chǎn)生的噪聲。 對(duì)象與方法 3 2 對(duì)象與方法 研究?jī)?nèi)容 本次研究擬收集企業(yè)常用的耳塞，采用真耳閾值方法對(duì)受試者進(jìn)行聽(tīng)閾檢測(cè)，通過(guò)對(duì)各種耳塞的各頻段降噪值測(cè)量，評(píng)估護(hù)耳器的實(shí)際 A 聲級(jí)降噪值，與護(hù)耳器出廠標(biāo)注的 SNR 和 NRR 值估算的 A 聲級(jí)降噪值進(jìn)行比較，并探討實(shí)驗(yàn)測(cè)得的實(shí)際 A 聲級(jí)降噪值與 SNR 值或 NRR 值之間的關(guān)聯(lián)性。 實(shí)施階段 （ 1） 應(yīng)讓受試者充分了解試驗(yàn)的情況和步驟，實(shí)驗(yàn)人員應(yīng)向每個(gè)受試者說(shuō)明試驗(yàn)的目的是測(cè)定實(shí)際降噪值，應(yīng)由知情的、有責(zé)任心的志愿者來(lái)完成，以 對(duì)象與方法 7 （ 2） 提高受試者的依從性。 ＜ 4 177。 理論上耳塞的 SNR、 NRR 值越大，耳塞的防噪效果就越好。s performers of the troupe still tour the region39。 work lives easier, but I simply could not digest the fact that that was my sole purpose in life. With no family to support, I was the sole beneficiary of my employment: the paycheck, the benefits, the incentives and the rewards were mine alone. Not much of a purpose in being selfserving, is there? While I was a student, I felt I was leading a purposeful life. Learning new things, broadening my horizons, expanding my life experiences all gave my life a zip and drive that I had not felt since being in survival mode when my kids were small. After graduating college I felt oddly deflated… but by then, China was on my horizon. 。s Poly Theater. Their show, titled Ulan Muqir on the Grassland, depicted the history and development of the art troupe. Being from the region allowed me to embrace the culture of Inner Mongolia and being a member of the troupe showed me where I belonged, Nasun, the art troupe39?？赡艿脑?yàn)椋? 2～ 6 號(hào)耳塞都是泡棉耳塞，其降噪值的差別主要取決于耳塞的形狀。 ＜ 6 177。 （ 4） 佩戴好耳塞后，給測(cè)試音測(cè)試，讓受試者調(diào)整耳塞的佩戴情況， 使聽(tīng)到的聲音最小來(lái)達(dá)到最佳降噪效果。 （ 2）參加測(cè)試的受試者，在 2021Hz 和 2021Hz 以下各頻率測(cè)得的每一耳的聽(tīng)閾級(jí)，應(yīng)不大于 15dB， 2021Hz 以上各頻率應(yīng)不大于 25dB。 生產(chǎn)性噪聲對(duì)作業(yè)人員的健康和生活質(zhì)量產(chǎn)生嚴(yán)重的影響。 關(guān)鍵詞 耳塞；純音氣導(dǎo)聽(tīng)閾測(cè)聽(tīng)法； A 聲級(jí)降噪值 Abstract Ⅱ Abstract Objectives: Collecting 6 kinds of earplugs that usually used by the enterprises,then measure the hearing threshold of 6 women measure the threshold denoising of all frequency ranges to estimate the actual A levels noise reduction of the earplug,to evaluate the actual noise reduction effect of the can provide a useful reference for the evaluation of occupational hazards in construction project in earplug protective effect evaluation and selection of enterprise earplugs. Methods: Selecting six adult women volunteers that whose air conduction hearing thresholds under 20dB, exclude tinnitus, otitis media and noise exposure history. Using the pure tone air conduction threshold audiometry to measure the change of the hearing threshold after with singlesample ttest mode to pare the actual A levels noise reduction of each earplug with A sound level of noise estimated fr