• 제목/요약/키워드: PA66

검색결과 149건 처리시간 0.026초

(Fe, TiH2, C) 혼합 분말로부터 제조된 Fe-30 wt% TiC 복합재료 분말의 소결 (Sintering of Fe-30 wt% TiC Composite Powders Fabricated from (Fe, TiH2, C) Powder Mixture)

  • 이병훈;김지순
    • 한국분말재료학회지
    • /
    • 제22권5호
    • /
    • pp.356-361
    • /
    • 2015
  • Fe-30 wt% TiC composite powders are fabricated by in situ reaction synthesis after planetary ball milling of (Fe, $TiH_2$, Carbon) powder mixture. Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe-30 wt% TiC composite powder compacts. Pressureless sintering is performed at 1100, 1200 and $1300^{\circ}C$ for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature of $1050^{\circ}C$, soaking time of 10 min, sintering pressure of 50 MPa, heating rate of $50^{\circ}C/min$, and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) are obtained from the data stored automatically during sintering process. The densification behaviors are investigated from the observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder compacts are not densified even after sintering at $1300^{\circ}C$ for 3 h, which shows a relative denstiy of 66.9%. Spark-plasma sintering at $1050^{\circ}C$ for 10 min exhibits nearly full densification of 99.6% relative density under the sintering pressure of 50 MPa.

한국산 산민달팽이 ( Incilaria fruhstorferi ) 소화관 상피조직의 미세구조 및 조직화학적 연구 (Ultrastructural and Histochemical Study on the Epithelia of Digestive Tract of a Korean Slug, Incilaria fruhstorferi)

  • 이정찬;장남섭;한종민
    • 한국패류학회지
    • /
    • 제13권2호
    • /
    • pp.143-160
    • /
    • 1997
  • 한국산 산민달팽이 Incilariafruhstorferi의 소화관을 부위별로 관찰하고, 소화관 상피조직을 구성하는 세포의 종류와 분포수 그리고 분비되는 과립 등을 미세구조적, 조직화학적으로 관찰하고 그 결과를 보고하고자 한다. 산민달팽이의 소화관은 식도, 위, 장, 직장 등으로 구성되어있으며, 식도는 다시 전식도, 소낭, 후식도로 나누어지고, 장은 전장과 중장, 후장 등으로 구분되었다. 소화관을 부위별롸 관찰한 결과 섬모원주상피세포 2종, 녹색과립세포 3종, 청색과립세포, 점액세포, 투명세포, 망상형세포 그리고 괴사형세포 등 모두 10종류가 확인되었다. 섬모원주세포는 A형과 B형 등 두 종으로 나뉘며, A형은 세포의 상단 자유면에 섬모와 미세융모가 밀생된데 비해, B형은 전자밀도가 높아서 검게 보이고, 장과 직장에서만 관찰되는 특징을 보였다. 섬모의 구조는 9 x 2 + 2 axoneme이었다. 녹색과립세포는 미세구조에 의해 A형, B형 그리고 C형등 3종으로 나누어지며, 소낭과 후식도, 위, 직장에서 주로 관찰되었다. A형과 B형은 Sudan black에 양성인 지방과립(1.36 x 1.6$\mu\textrm{m}$)만을 포함하고 있는데비해 C형은 글리코겐 과립도 포함하고 있었다. 청색과립세포는 10종류의 세포 중 가장 키가 크고 (35$\mu\textrm{m}$), Millon반응에 양성을 보이는 둥근과립(직경, 1.3$\mu\textrm{m}$)을 포함하고 있는데 과립들은 단백질성으로 확인되었다. 이들은 중장에서만 관찰되었다. 장과 직장에서 주로 많이 관찰되는 점액세포는 세포질 속에 전자밀도가 낮은 투명한 과립과 전자밀도가 높아서 검게 보이는 둥근과립(크기, 1.33 x 0.89$\mu\textrm{m}$)들을 포함하고 있었는데, 이들은 미성숙 시기에는 투명과립(직경, 2.66$\mu\textrm{m}$)으로 관찰되었다. PAS-alcian blue(pH 2.5)반응에서 투명과립은 alcianophillia로 나타난 반면, 검은 과립은 PAS에 양성반을을 보이며, 각각 산성점액과 중성점액과립으로 확인되었다. 투명세포는 광학현미경 관찰에서 A형과 B형으로 구분되었으나, A형은 전자현미경 관찰에서 신경내분비세포로 확인된 반며, B형은 지방과립을 소지한 지방저장세포로 각각 확인되었다. 신경내분비세포가 소지한 과립의 크기는 0.16$\mu\textrm{m}$ 정도였다. 망상형세포는 주로 위에서 관찰되는 형태가 불규칙한 작은 세포로서 세포질에 비해 큰 핵을 소지하고 있었다. 소량의 세포질 돌기에는 사립체와 과립성소포체를 포함하고 있다. 괴사형세포는 후장과 직장에서 주로 많이 관찰되고, 점액세포의 점액과립이 분비된 후, 붕괴되는 과정에서 형성된 것으로 확인되었다.

  • PDF

1979~2011년, 북극진동지수 측면에서의 겨울철 남한지역 신적설과 최저 온도 특성 (A Characteristic of Wintertime Snowfall and Minimum Temperature with Respect to Arctic Oscillation in South Korea During 1979~2011)

  • 노준우;이용희;최규용;이희춘
    • 대기
    • /
    • 제24권1호
    • /
    • pp.29-38
    • /
    • 2014
  • A characteristic of snowfall and minimum temperature variability in South Korea with respect to the variability of Arctic Oscillation (AO) was investigated. The climatic snowfall regions of South Korea based on daily new fresh snowfall data of 59 Korea Meteorological Administration (KMA) stations data corresponding to the sign of AO index during December to February 1979~2011 were classified. Especially, the differences between snowfalls of eastern regions and that of western regions in South Korea were seen by each mean 1000hPa geopotential height fields, which is one of physical structure, for the selected cases over the East Asia including the Korean Peninsula. Daily minimum temperature variability of 59 KMA station data and daily AO index during the same period were investigated using Cyclo-stationary empirical orthogonal function (CSEOF) analysis. The first CSEOF of wintertime daily AO index and that of minimum temperature of 59 KMA stations explain 33% and 66% of total variability, respectively. Correlation between principal component time series corresponding to the first CSEOF of AO index and that of temperature at the period of 1990s is over about -0.7 when that of AO index leads about 40 days.

Analysis of Gene Expression in Carcinogen-induced Acute Hepatotoxicity

  • Oh, Jung-Hwa;Park, Han-Jin;Lee, Eun-Hee;Heo, Sun-Hee;Cho, Jae-Woo;Kim, Yong-Bum;Yoon, Seok-Joo
    • Molecular & Cellular Toxicology
    • /
    • 제5권1호
    • /
    • pp.58-66
    • /
    • 2009
  • The 2-year rodent carcinogenicity test involves long-term, repetitive dosing of animals that is both time consuming and expensive. Alternative approaches have been attempted using specific transgenic or knockout mice or toxicogenomics to predict carcinogenicity without conducting a 2-year rodent test. In addition, toxicogenomic analysis of carcinogen-treated animals could also enhance our understanding of molecular mechanisms and aid in the diagnosis of acute toxicity induced by carcinogens. Therefore, we investigated transcription profiles after administering the carcinogens 4,4-dimethylformamide (DMF) and 4-biphenylamine (ABP). BALB/c male mice were treated once with DMF (650 mg/kg i.p.) or ABP (120 mg/kg p.o.). Standard blood biochemistry and histological changes were observed. Gene expression profiles in the livers of mice treated with either vehicle or the carcinogens were analyzed using the Affymetrix $GeneChip^{(R)}$ assay. In all, 1,474 differentially expressed genes in DMF- or ABP-treated mice were identified as being either up- or down-regulated over 1.5-fold (P< 0.01), and these genes were analyzed using hierarchical clustering and Ingenuity Pathways Analysis. Of these, 107 genes were consistently regulated in both carcinogen-treated groups. Genes associated with cancer were upregulated (Por, S100a10, Tes, Ctcf, Ddx21, Eapp, Nel, and Pa2g4) or downregulated (Cbs and Gch1). Toxicological function analysis also identified genes involved in organ toxicity, including hepatotoxicity. These data may help to identify molecular markers for acute hepatotoxicity induced by carcinogens.

Critical pathway 적용을 통한 급성 뇌졸중 환자의 응급실 체류시간 단축 효과 (Reduction of Length of Stay in Emergency Room by Using Critical Pathway for Stroke Patients)

  • 윤여옥;김민영;김우정;강영준;박주옥;박경혜
    • 간호행정학회지
    • /
    • 제17권1호
    • /
    • pp.66-73
    • /
    • 2011
  • Purpose: The purpose of this study was to demonstrate effects of a critical pathway (CP) for stroke patients seen in emergency rooms (ER). Method: The CP developed by the CP committee consisted of 8 criteria: behavior of doctors and nurses, laboratory tests, Image testing, medication, treatment, activity, and nutrition. According to application of CP, a control group (n=17) and experimental group (n=17) were defined. Time was checked by the electronic medical records. Result: Use of CP for stroke patients in the ER, resulted in a decreased length of stay in ER (t=2.341, p=.026), and time required for image testing (t=2.623, p=.021), and an increased number of patients using rtPA ($x^2$=4.802, p=.049). Time required for neurology doctor contact, for neurology doctor to see patient in the ER, and for report of blood tests decreased, but there were no statistical significance. Conclusion: Quick responses are most important in the ER, so CP for these patients is a very effective patient management tool. To reduce delay in stroke diagnosis, continuous education programs for similar symptoms are necessary. CPs for other patients in the ER should be developed, and studies on cost and satisfaction, as well as length of stay, should be done.

팰래듐과 테루리움계의 상평형 연구 (Phase Constitution of the Palladium and Tellurium System)

  • 김원사
    • 한국결정학회지
    • /
    • 제1권2호
    • /
    • pp.66-75
    • /
    • 1990
  • Pd-Te계의 상평형도를 시차열분석, X선회절분석, 전자현미분석, 반사현미경을 사용해 연구하였다. 본 계의 0-50 at.%Te 부분의 새로운 상관계가 정립되었다. 본 계에는 Pd17Te4, Pd20Te7, Pd8Te3, Pd7Te3, PdgTe4, Pd3Te2, PdTe, PdTe2 등 8개의 화합물이 존재하며 이중 Pd17Te4와 Pd7Te3는 처음 보고되는 신종 화합물이다. Pd17Te4는 등축정계이며 공간군 Fd3r에 속하며 단위포 크기 (a)는 12. 678(5)차이다. PdaTe.4와Pd7Te3의 X선회절분말자료는 사방정계의 단위포 a=12.843(3), b=15.126(3), c=11.304(2)A와 단사 정계의 단위포 a=7.444(1), b=13.918(2), c=8.873 (2)il, β=92.46(2)에 의해 각각 격자지수화가 가능하였다. 본계에 존재하는 합성 화합물의 일부 물리적, 광학적 자료를 새로 보고하였다.

  • PDF

제주 연안에서 양식된 참조기의 청각 능력 (Hearing Ability of Redlip croaker Pseudosciaena polyactis cultured in the Coastal Sea of Jeju)

  • 안장영;김석종;최찬문;박용석;이창헌
    • 수산해양교육연구
    • /
    • 제28권2호
    • /
    • pp.384-390
    • /
    • 2016
  • The purpose of this paper is to improve the availability of underwater sound by the fundamental data on the hearing ability of Redlip croaker Pseudosciaena polyactis, which is cultured according to the cultivation technology, recently. The auditory thresholds of Redlip croaker were determined at 6 frequencies from 80Hz to 800Hz by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the Redlip croaker extended from 80Hz to 800Hz with the best sensitive frequency range including little difference in hearing ability from 80Hz to 500Hz. In addition, the auditory thresholds over 800Hz increased rapidly. The mean auditory thresholds of the Redlip croaker at the test frequencies from 80Hz to 800Hz were 90.7dB, 93.4dB, 92.9dB, 94.4dB, 95.5dB and 108dB, respectively. Auditory masking for the redlip croaker was measured using masking stimuli with the spectrum level range of about 66, 71, 75dB (0dB re $1{\mu}Pa/{\sqrt{Hz}}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The Auditory masking by the white noise spectrum level was stared over about 70dB within 80~500Hz. Critical ratio ranged from minimum 20.7dB to maximum 25.5dB at test frequencies of 80Hz~500Hz.

흉부 방사선영상의 좌, 우 반전 발생 여부 컨벌루션 신경망 기반 정확도 평가 (An Accuracy Evaluation on Convolutional Neural Network Assessment of Orientation Reversal of Chest X-ray Image)

  • 이현우;오주영;이주영;이태수;박훈희
    • 대한방사선기술학회지:방사선기술과학
    • /
    • 제43권2호
    • /
    • pp.65-70
    • /
    • 2020
  • PA(postero-anterior) and AP(antero-posterior) chest projections are the most sought-after types of all kinds of projections. But if a radiological technologist puts wrong information about the position in the computer, the orientation of left and right side of an image would be reversed. In order to solve this problem, we utilized CNN(convolutional neural network) which has recently utilized a lot for studies of medical imaging technology and rule-based system. 70% of 111,622 chest images were used for training, 20% of them were used for testing and 10% of them were used for validation set in the CNN experiment. The same amount of images which were used for testing in the CNN experiment were used in rule-based system. Python 3.7 version and Tensorflow r1.14 were utilized for data environment. As a result, rule-based system had 66% accuracy on evaluating whether the orientation reversal on chest x-ray image. But the CNN had 97.9% accuracy on that. Being overcome limitations by CNN which had been shown on rule-based system and shown the high accuracy can be considered as a meaningful result. If some problems which can occur for tasks of the radiological technologist can be separated by utilizing CNN, It can contribute a lot to optimize workflow.

Modelling of starch industry wastewater microfiltration parameters by neural network

  • Jokic, Aleksandar I.;Seres, Laslo L.;Milovic, Nemanja R.;Seres, Zita I.;Maravic, Nikola R.;Saranovic, Zana;Dokic, Ljubica P.
    • Membrane and Water Treatment
    • /
    • 제9권2호
    • /
    • pp.115-121
    • /
    • 2018
  • Artificial neural network (ANN) simulation is used to predict the dynamic change of permeate flux during wheat starch industry wastewater microfiltration with and without static turbulence promoter. The experimental program spans range of a sedimentation times from 2 to 4 h, for feed flow rates 50 to 150 L/h, at transmembrane pressures covering the range of $1{\times}10^5$ to $3{\times}10^5Pa$. ANN predictions of the wastewater microfiltration are compared with experimental results obtained using two different set of microfiltration experiments, with and without static turbulence promoter. The effects of the training algorithm, neural network architectures on the ANN performance are discussed. For the most of the cases considered, the ANN proved to be an adequate interpolation tool, where an excellent prediction was obtained using automated Bayesian regularization as training algorithm. The optimal ANN architecture was determined as 4-10-1 with hyperbolic tangent sigmoid transfer function transfer function for hidden and output layers. The error distributions of data revealed that experimental results are in very good agreement with computed ones with only 2% data points had absolute relative error greater than 20% for the microfiltration without static turbulence promoter whereas for the microfiltration with static turbulence promoter it was 1%. The contribution of filtration time variable to flux values provided by ANNs was determined in an important level at the range of 52-66% due to increased membrane fouling by the time. In the case of microfiltration with static turbulence promoter, relative importance of transmembrane pressure and feed flow rate increased for about 30%.

HRCT Emphysema Scoring과 운동부하 폐기능검사 지표들 간의 상관관계 (The Correlation between HRCT Emphysema Score and Exercise Pulmonary Testing Parameters)

  • 최은경;최영희;김도형;김용호;윤세영;박재석;김건열;이계영
    • Tuberculosis and Respiratory Diseases
    • /
    • 제50권4호
    • /
    • pp.415-425
    • /
    • 2001
  • 배 경 : 폐기종의 중증도 판정에 있어서 병리학적 기준은 기강(air space)의 확장 정도에 있으며, 이는 고해상도 전산화 촬영 (high resolution computed tomography, HRCT)에 의해 결정되는 폐기종 점수(emphysema scoring)와 좋은 상관성을 보인다는 것은 주지의 사실이다. 한편 폐기종의 주증상은 운동성 호흡곤란이므로 폐기종에 대한 임상적 평가는 운동능력의 감소를 측정하는 것이 타당하다고 알려져 있다. 그러나 대개의 경우 폐기종의 중증도 판정은 안정시 폐기능 검사에 의존하는 경우가 흔하며, 병리학적 중증도 판정과 상관성이 높다고 알려져 있는 고해상도 전산화 촬영에 의한 폐기종 점수와 운동부하 폐기능검사 지표들과의 상관성 여부에 대한 연구는 드문 실정이다. 이에 본 연구에서는 폐기종의 중증도 판정에 있어서 HRCT와 안정시 폐기능 검사 및 운동부하 폐기능 검사간에 상호 관련성을 확인하여 보았다. 방 법 : 평균 연령 $60.6{\pm}10.3$세인 14명의 폐기종 환자들을 대상으로 HRCT, 안정시 폐기능 검사(forced expiratory flow volume curve, lung volumes by He dilution method, DLco, ABGA), 그리고 점진적운동부하폐 기능검사(incremental cycle ergometer)를 시행하였으며 HRCT는 GE highlight를 이용하여 조영증강 없이 최대흡기시에 1.5mm collimation, 10mm 간격으로 폐전체를 스캔하였고, 환자마다 모든 스캔에서 density mask를 이용하여 -400 HU를 기준으로 한 총폐면적과 -900 HU를 기준으로 한 폐기종 면적을 각각 구하여 백분율로 환산하여 폐기종 점수를 구하였다. 결 과 : 평균 폐기종 점수는 $37.4{\pm}14.9%$ 이었다. 폐기종 점수와 안정시 폐기능 검사의 DLco(r=-0.75)와 $PaO_2$(r=-0.66) 사이에서만 유의한(p<0.05) 상관성이 관찰되었다. 반면 폐기종 점수와 운동부하폐기능 지표들간의 상관성은 최대 산소섭취량(r=-0.68), 혐기성 역치(V-slope method, r=-0.690), 최대운동부하(r=-0.74), 최대운동시 $O_2$ pulse(r=-0.73), 최대운동시의 생리적 사강비율 (r=0.80) 등과 높은 유의성 (p<0.01)을 나타내었다. 그러나 호흡예비율과 심박수 예비율간에서는 유의한 상관성이 없었고, pulse oxymeter로 측정한 산소포화도와의 상관성도 유의하지 않았다. 결 론 : 이상의 결과에서 폐기종의 병리학적 중증도를 잘반영한다고 알려진 HRCT 폐기종 접수는 폐기종에 의한 생리학적 장애를 잘 반영하는 운동부하 폐기능 검사의 주요 지표들과 유의한 상관성이 있음을 확인할 수 있었다.

  • PDF