著者
牧野 裕介 高野 靖
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 (ISSN:21879761)
巻号頁・発行日
vol.87, no.899, pp.21-00052, 2021 (Released:2021-07-25)
参考文献数
19

The variation of the noise metrics of a group of sound sources due to its movement at a constant velocity along a straight track is discussed in the paper. When sound sources move, frequency and amplitude modulation is observed in the radiated sound field. The frequency and amplitude increase when sound sources are approaching and decrease when going away. We found that when frequency and amplitude modulation were considered, the calculated noise levels LAmax, LASmax, LAeq,T became larger than the calculated levels without their consideration. The difference of the calculated levels between the cases increased with respect to the sound source velocity. This difference was independent of distance between the track and the receiving point. Approximating discrete sound sources in line by a finite line source would underestimate the noise level. The level of this underestimation would increase by decreasing source division. The underestimated level was calculated for sources with reference noise spectrum for rolling stocks with a constant sound power level as we focused on the influence of frequency and amplitude modulation on the radiated sound field. The underestimated level was large for LAmax and LASmax compared with LAeq,T. The difference of the calculated levels between the cases decreased monotonically with respect to the source frequency.
著者
武藤 大輔 高野 靖
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 C編 (ISSN:03875024)
巻号頁・発行日
vol.74, no.746, pp.2495-2503, 2008-10-25 (Released:2011-03-04)
参考文献数
5
被引用文献数
3 3

The dependence of transmission loss (TL) of a double-wall structure on the characteristics of the gases between the walls was investigated. The relationship between acoustic impedance, acoustic velocity, and TL was calculated by using the transfer matrix method. The results indicated that characteristics of the internal gases have two effects on TL. One is a change in the double-wall effect, and the other is a change in the reflection coefficient. Gases that have slower acoustic velocities or lower acoustic impedance than air increase the double-wall effect. Gases that have faster acoustic velocities increase the reflection coefficient. The calculated results for TL with air, helium, and carbon dioxide agreed well with experimental measurements. Finally, The rating of sound insulation (Rw) defined by JIS A1419-1 (ISO-717) was introduced, and the relationship between Rw and the characteristics of the gases between walls was investigated. The results indicate that gas with a low molecular weight and large ratio of specific heat is more effective to increase the TL.
著者
渡辺 隆行 大城 貞次 守田 昌美 八木 敦子 今井 厚 寺島 茂 高野 靖悟
出版者
一般社団法人 日本農村医学会
雑誌
日本農村医学会学術総会抄録集 (ISSN:18801749)
巻号頁・発行日
vol.58, pp.104, 2009

〈はじめに〉わが国のHelicobacter pylori(以下H. ピロ<BR>リ)感染者は推定5,000万人とも言われている。H. ピロリ<BR>は胃炎や胃十二指腸潰瘍の主な原因として,さらに胃癌と<BR>の関わりも注目されている。当院では2005年よりH. ピロ<BR>リ感染診断と除菌判定法の検査として尿素呼気試験,2008<BR>年4月より尿中H. ピロリ抗体検査を行っている。尿素呼<BR>気試験は非侵襲的,簡便で感度,特異度ともに高く,尿素<BR>呼気試験陰性の場合は除菌成功の信頼性は高い。<BR>〈目的〉H. ピロリ検査の現状を把握し,スクリーニング<BR>検査として人間ドックに新規検査項目としての導入効果が<BR>あるか検討した。<BR>〈方法〉2008年2月から2009年1月までの1年間における<BR>尿素呼気試験440件の陽性率,年代別検査依頼数と陽性<BR>率,尿中H. ピロリ抗体の陽性率と尿素呼気試験陽性患者<BR>の除菌治療後の除菌成功率について検討した。<BR>〈結果〉尿素呼気試験陽性率は27%であった。年代別検査<BR>依頼数と陽性率を比較すると,30代では42件で38%,40代<BR>では66件で23%,50代では105件で23%,60代では151件で<BR>26%,70代では58件で33%,80代以上では14件で29%で<BR>あった。尿中H. ピロリ抗体の陽性率は58%であった。陽<BR>性患者の除菌治療後の除菌成功率は85%であった。<BR>〈考察〉尿素呼気試験陽性患者の除菌治療後の除菌失敗率<BR>は15%であった。薬剤耐性菌の存在も確認されたとの報告<BR>もあり,1回の除菌だけでは効果がない場合も考えられ<BR>る。尿素呼気試験と尿中H. ピロリ抗体との陽性率の比較<BR>では,尿素呼気試験の陽性率が低くなったことからも,今<BR>後,人間ドックのスクリーニング検査としては,検体採取<BR>が容易で迅速に結果報告が可能な尿中H. ピロリ抗体を行<BR>い,除菌後は尿素呼気試験でH. ピロリの有無を評価する<BR>方法を提案していきたい。<BR>
著者
武藤 大輔 高野 靖 山口 誉夫
出版者
一般社団法人 日本機械学会
雑誌
日本機械学会論文集 (ISSN:21879761)
巻号頁・発行日
vol.83, no.855, pp.17-00106-17-00106, 2017 (Released:2017-11-25)
参考文献数
11

To increase the noise proof performance of a cover with aperture excited by diffuse acoustic fields from the outside, it is a problem to prevent the occurrence of the inner acoustic mode at the lower frequencies. Authors had suggested the feed forward active noise control (ANC) for the acoustic field inside the cover. Diffuse acoustic field excitation experiment using reverberant room has been examined to comprehend acoustic characteristics inside the cover. The results show that the inner cover field is in the state of locally coherent at the frequencies of inner acoustic mode, so that it is good environment for the active noise control. Then, a calculation with two-dimensional finite difference time domain (FDTD) method has been done to examine the feasibility of feed forward ANC. The results show that it is possible to realize ANC for the acoustic field inside the cover by proper design of control filter. Finally, experimental measurement of diffuse acoustic field excitation in the reverberant room has been done again to examine the ANC with the design method mentioned above. The results show that feed forward ANC can reduce noise level by 5dB at the peak frequency caused by the inner acoustic mode. Furthermore, the inner acoustic pressure distribution is also reduced uniformly at the frequency. Therefore, it is concluded that it is possible to realize feed forward active noise control for the acoustic field inside the cover with aperture excited by diffuse acoustic fields from the outside, even if the excitation is random or the causality of I/O is not satisfied.
著者
西沢 直行 高野 靖 神立 誠
出版者
公益社団法人 日本分析化学会
雑誌
分析化学 (ISSN:05251931)
巻号頁・発行日
vol.25, no.5, pp.294-298, 1976-05-10 (Released:2009-06-30)
参考文献数
26
被引用文献数
1 3

イオン交換クロマトグラフィーによる筋肉中のカルノシン,アンセリン,バレニンの分離,分析精度の向上,分析の迅速化を試み,よい結果を得た.分析は,56×0.25cmのカラムに強酸性陽イオン交換樹脂Aminex A-5を50cmの高さに充てんし,エタノールを2.5%含んだクエン酸緩衝液(pH4.15,ナトリウム濃度0.38M)で,カラム温度57℃,緩衝液の流量5.4ml/hで行った.本方法により,アミノ酸,エタノールアミン,クレアチニンの存在下で,カルノシン,アンセリン,バレニンが迅速に精度よく定量できる.分析所要時間はカルノシンまでで5時間40分で,分析精度は(100±1.2)%であった.本方法による筋肉の1回の分析必要量は0.02gである.マッコウクジラ,スジイルカ,ヒキガエル,ホタテガイの筋肉にバレニンの存在が認められた.