• 제목/요약/키워드: N95

검색결과 3,263건 처리시간 0.033초

수직 흐름 제올라이트 갈대 여과상의 간헐적 주입에 의한 인공하수 처리 (Vertical Flow Zeolite-Filled Reed Bed for Treatment of Artificial Sewage with Intermittent Feeding)

  • 서정윤;김태형;최민수
    • KSBB Journal
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    • 제18권2호
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    • pp.140-144
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    • 2003
  • 제올라이트로 충진된 수직 흐름 갈대 여과상에 인공하수를 주입하면서 처리효율을 조사하였다. 여과상 표면적 $m^2$당 1일 314 L의 인공하수가 6시간마다 10분 동안 간헐적으로 주입되었다 각 항목별 연중 평균 처리효율은 CO $D_{Cr}$ , 95.1%, T-N 49.5%, N $H_4$$^{+}$-N 99.4%, T-P 56.4%이었다. T-N의 처리효율은 가동 시간이 경과함에 따라 현저하게 감소하였다. 여과상의 상층에서 많은 인이 흡착되었으며 흡착된 인 중 대부분은 Fe-p, Ca-P와 환원가용성 Fe-P이었다.

수평 흐름 제올라이트 갈대 여과상에 의한 인공하수 처리 (Horizontal Flow Zeolite-Filled Reed Bed for Treatment of Artificial Sewage with Intermittent Feeding)

  • 서정윤;최민수
    • KSBB Journal
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    • 제18권6호
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    • pp.506-510
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    • 2003
  • 제올라이트로 충진된 수평 흐름 갈대 여과상에 인공하수를 주입하면서 처리효율을 조사하였다. 여과상 표면적 $m^2$당 1일 314 L의 인공하수가 6시간마다 10분 동안 간헐적으로 주입되었다. 각 항목별 연중 평균 처리효율은 CODcr 95.8%, T-N 56.5%, NH$_{4}$$^{+}$-N 99.4%, T-P 61.3%이었다. NH$_{4}$$^{+}$-N의 처리효율은 지속적으로 높게 유지되었으나 T-N의 처리효율은 가동 시간이 경과함에 따라 현저하게 감소하였다.

아로마테라피가 중년여성의 갱년기 증상, 스트레스 및 우울에 미치는 효과: 체계적 문헌고찰 (Effects of Aromatherapy on Menopausal Symptoms, Perceived Stress and Depression in Middle-aged Women: A Systematic Review)

  • 김신미;송지아;김미은;허명행
    • 대한간호학회지
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    • 제46권5호
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    • pp.619-629
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    • 2016
  • Purpose: This study was a systematic review to evaluate the effects of aromatherapy on menopausal symptoms, perceived stress and depression in middle aged-women. Methods: Eight databases were searched from their inception September 8, 2015. Two reviewers independently performed the selection of the studies, data abstraction and validations. The risk of bias was assessed using Cochrane criteria. For analysis of the data, a meta-analysis of the studies was performed. Results: From the electronic databases, 73 articles were selected, and 19 removed due to duplication. After two reviewers read the abstracts of 54 studies, 34 studies were selected. Complete papers for 34 s were read and, 12 studies which met selection criteria were reviewed and the effects of aromatherapy on menopausal symptoms, stress and depression analyzed using meta-analysis with RevMan. In the 2 studies which included Randomized Controlled Trials testing of aromatherapy on menopausal symptoms and comparison of control and placebo groups were done. Aromatherapy massage was favorably effective in reducing the menopausal symptoms compared to the control group (n=118, MD=-6.33; 95% CI -11.51 to -1.15), and compared to the placebo group (n=117, MD=-4.14; 95% CI -7.63 to -0.64). Also aromatherapy was effective in reducing stress (n=72, SMD=-0.64; 95% CI -1.12 to -0.17) and depression (n=158, MD=-5.63; 95% CI -10.04 to -1.22). Conclusion: There is limited evidence suggesting that aromatherapy for middle-aged women may be effective in controlling menopausal symptoms, perceived stress and depression.

시중에 판매되는 다양한 비인증 마스크의 분진 포집효율과 안면부 흡기저항 평가 (Evaluation of the Filtration Efficiency and Facial Inhalation Resistance of Various Commercial Masks)

  • 강소현;김수민;윤충식;이기영
    • 한국환경보건학회지
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    • 제47권3호
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    • pp.292-301
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    • 2021
  • Objectives: Wearing medical masks has been recommended since the declaration of coronavirus disease-19 (COVID-19) as a pandemic disease. Certified medical masks are evaluated according to filtration efficiency and facial inhalation resistance. However, some people use non-certified common masks. This study aimed to evaluate various non-certified commercial masks based on the certification criteria for medical masks. Methods: Twenty mask products (three anti-droplet, three disposable dental, eight fashion, three cotton, and three children's masks) were selected. For performance evaluation, filtration efficiency and facial inhalation resistance tests were conducted. The evaluation method followed the certification method for KF-certified masks of the Ministry of Food and Drug Safety (MFDS) and the N95 respirator of the National Institute for Occupational Safety and Health (NIOSH). Results: None of the 20 masks met the KF94 certification standard set by the MFDS. Four and three masks respectively met the KF80 certification standard and the N95 standard of NIOSH. Filtration efficiency was significantly higher in three-layer masks than in single layer masks. Pleated-type masks had higher filtration efficiency than cone-type masks. There was no correlation between the structure of masks and facial inhalation resistance. Conclusion: While no masks complied with the KF94 certification standard, a few masks met the KF80 and the N95 certification standards of NIOSH. Although some people wear non-certified commercial masks, protection from aerosols is not guaranteed by such masks. Evaluation of the protection efficiency of non-certified mask against microbiological infection is needed for the prevention of infectious disease.

휴식과 운동 중 COVID-19 대응 보건용 마스크 착용이 호흡·심혈관계 반응 및 착용감에 미치는 영향 (Effects of Wearing COVID-19 Protective Face Masks on Respiratory, Cardiovascular Responses and Wear Comfort During Rest and Exercise)

  • 정재연;강찬혁;성유찬;장세혁;이주영
    • 한국의류산업학회지
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    • 제22권6호
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    • pp.862-872
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    • 2020
  • This study explores the effects of facemasks on respiratory, thermoregulatory, cardiovascular responses during exercise on a treadmill and at rest. Five male subjects (25.8 ± 0.8 y, 171.8 ± 9.2 cm in height, 79.8 ± 28.1 kg in weight) participated in the following five experimental conditions: no mask, KF80, KF94, KF99, and N95. Inhalation resistance was ranked as KF80 < KF94 < N95 < KF99 and dead space inside a mask was ranked as KF80 = KF94 < N95 < KF99. The surface area covered by a mask was on average 1.1% of the total body surface area. The results showed no significant differences in body core temperature, oxygen consumption (VO2), carbon dioxide production (VCO2), heart rate or subjective perception among the five experimental conditions; however, cheek temperature, respiratory ventilation and blood pressure were greater for KF80 or KF94 conditions when compared to KF99 or N95 conditions (p<0.05). The differences among mask conditions are attributed to the dead space or specific designs (cup type vs pleats type) rather than the filtration level. In addition, the results suggest that improving mask design can help mitigate respiratory resistance from increased filtration.

Ta-Si-N박막의 조성에 따른 결정구조 및 구리 확산 방지 특성 연구 (Crystalline Structure and Cu Diffusion Barrier Property of Ta-Si-N Films)

  • 정병효;이원종
    • 한국재료학회지
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    • 제21권2호
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    • pp.95-99
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    • 2011
  • The microstructure and Cu diffusion barrier property of Ta-Si-N films for various Si and N compositions were studied. Ta-Si-N films of a wide range of compositions (Si: 0~30 at.%, N: 0~55 at.%) were deposited by DC magnetron reactive sputtering of Ta and Si targets. Deposition rates of Ta and Si films as a function of DC target current density for various $N_2/(Ar+N_2)$ flow rate ratios were investigated. The composition of Ta-Si-N films was examined by wavelength dispersive spectroscopy (WDS). The variation of the microstructure of Ta-Si-N films with Si and N composition was examined by X-ray diffraction (XRD). The degree of crystallinity of Ta-Si-N films decreased with increasing Si and N composition. The Cu diffusion barrier property of Ta-Si-N films with more than sixty compositions was investigated. The Cu(100 nm)/Ta-Si-N(30 nm)/Si structure was used to investigate the Cu diffusion barrier property of Ta-Si-N films. The microstructure of all Cu/Ta-Si-N/Si structures after heat treatment for 1 hour at various temperatures was examined by XRD. A contour map that shows the diffusion barrier failure temperature for Cu as a function of Si and N composition was completed. At Si compositions ranging from 0 to 15 at.%, the Cu diffusion barrier property was best when the composition ratio of Ta + Si and N was almost identical.

Robust Reference Intervals for Serum Kappa and Lambda Free Light Chains from a Multi Centre Study Population from Hyderabad, India: Myeloma Diagnostic Implications

  • Mohammed, Noorjahan;Chandran, Priscilla Abraham;Kandregula, Madhavi;Mattaparthi, Ratna Deepika;Gundeti, Sadasivudu;Volturi, Jyotsna;Darapuneni, Radhika;Raju, Sree Bhushan;Dattatreya, Palanki Satya
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권5호
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    • pp.2605-2610
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    • 2016
  • The International Myeloma Working Group considers the serum free light chain (SFLC) assay to be an adjunct to traditional tests. Apart from the FLC ratio, the absolute values of individual free light chains also are gaining importance as they appear to be more relevant in certain clinical settings. Automated assays are available for their determination. As laboratories put new test systems into use catering to different disease populations, they are required by accreditation and certification bodies to verify or establish performance specifications, including reference intervals (RIs) representative of their population. Our aim was to establish local RIs for SFLC in a multicentre representative healthy population using a robust method. There was no significant relationship between SFLC levels and age, gender and creatinine levels. The 95% RI for ${\kappa}SFLC$ was 4.81 to 33.86mg/L, for ${\lambda}$ SFLC was 5.19 to 23.67mg/L and for ${\kappa}/{\lambda}SFLC$ was 0.36 to 2.33, significantly higher than the values given by the manufacturer. The ${\kappa}/{\lambda}$ SFLC ratio at 2.23, covering 100% of the data, showed 72% sensitivity (95% CI=39.0 - 94.0), 100% specificity (95% CI=71.5 - 100.0), 100% PPV (95% CI=21.5 - 100.0), 95% NPV (95% CI=75.4 - 99.9), and 79% accuracy (95% CI=56.0 - 93.0). In the patient group, kit RI for ${\kappa}/{\lambda}$ SFLC ratio classified 45.5% (n=5) as positive vs 9.1% (n=1) positive by the study RI, while the kit RI for kappa FLC classified 90.9% (n=10) as positive vs 54.5% (n=6), indicating increased probability of false positive test results with the kit RI when applied to our patient population. Appropriate and specific reference intervals and criteria values result in fewer false-positive and false-negative results which means fewer wrong or missed diagnoses.

한국 노인여성의 비만, 복부비만 기준에 따른 대사증후군 위험요인의 차이 (The Differences of Metabolic Syndrome Risk Factors according to Obesity and Abdominal Obesity in Elderly Korean Women)

  • 신경아
    • 대한임상검사과학회지
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    • 제48권4호
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    • pp.304-311
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    • 2016
  • 이 연구는 노인여성을 대상으로 비만, 복부비만 기준에 따른 대사증후군 위험요인의 차이를 알아보고, 비만 유형과 대사증후군 위험요인과의 관련성을 규명하고자 하였다. 비만 기준은 세계보건기구 아시아 태평양 기준에서 제시한 비만 기준을 따랐으며, 대사증후군은 The National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III)의 진단기준에 따라 분류하였다. 연구 대상자 591명 중 정상군 272명, 단순비만군 124명, 복부비만군 19명, 비만-복부비만군 176명 이었다. 비만, 복부비만 기준에 따른 대사증후군 위험요인의 유병률 차이를 비교한 결과 낮은 HDL-콜레스테롤혈증(p=0.009), 고중성지방혈증(p=0.025), 복부비만(p<0.001), 대사증후군 진단 유병률(p<0.001)은 집단간 차이를 보였으며, 비만-복부비만군에서의 유병률이 높게 나타났다. 로지스틱 회귀분석을 통해 복부비만 기준에 따른 비만유형과 대사증후군 각각의 위험요인 및 대사증후군 진단간의 관련성을 분석한 결과, 정상군에 비해 단순비만군에서 낮은 HDL-콜레스테롤혈증의 발생이 1.6배 높았으며(odds ratio, OR: 1.576, 95% confidence interval, 95% CI: 1.006~2.469), 비만-복부비만군에서는 1.9배 높은 양상을 보였다(OR: 1.882, 95% CI: 1.266~2.799). 고중성 지방혈증은 정상군보다 비만-복부비만군에서 1.9배 높았다(OR: 1.904, 95% CI: 1.246~2.910). 또한 정상군보다 복부비만군에서 대사증후군 발생이 6.6배 높았으며(OR: 6.579, 95% CI: 2.233~19.385), 비만-복부비만군의 경우 10.6배 높은 양상을 보였다(OR: 10.638, 95% CI: 6.053~18.697).