• 제목/요약/키워드: morphological parameters

검색결과 357건 처리시간 0.03초

One-step microwave synthesis of surface functionalized carbon fiber fabric by ZnO nanostructures

  • Ravi S. Rai;Vivek Bajpai
    • Advances in nano research
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    • 제14권6호
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    • pp.557-573
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    • 2023
  • The rapid growth of zinc-oxide (ZnO) nanostructures (NSs) on woven carbon fiber (WCF) is reported in this study employing a microwave-aided chemical bath deposition process. The effects of different process parameters such as molar concentration, microwave duration and microwave power on morphologies and growth rate of the ZnO on WCF were studied. Furthermore, an attempt has been taken to study influence of different type of growth solutions on ZnO morphologies and growth rates. The surface functionalization of WCF fabrics is achieved by successful growth of crystalline ZnO on fiber surface in a very short duration through one-step microwave synthesis. The morphological, structural and compositional studies of ZnO-modified WCF are evaluated using field-emission scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy respectively. Good amount of zinc and oxygen has been seen in the surface of WCF. The presence of the wurtzite phase of ZnO having crystallite size 30-40 nm calculated using the Debye Scherrer method enhances the surface characteristics of WCF fabrics. The UV-VIS spectroscopy is used to investigate optical properties of ZnO-modified WCF samples by absorbance, transmittance and reflectance spectra. The variation of different parameters such as dielectric constants, optical conductivity, refractive index and extinction coefficient are examined that revealed the enhancement of optical characteristics of carbon fiber for wide applications in optoelectronic devices, carbon fiber composites and photonics.

Role and Clinical Importance of Progressive Changes in Echocardiographic Parameters in Predicting Outcomes in Patients With Hypertrophic Cardiomyopathy

  • Kyehwan Kim;Seung Do Lee;Hyo Jin Lee;Hangyul Kim;Hye Ree Kim;Yun Ho Cho;Jeong Yoon Jang;Min Gyu Kang;Jin-Sin Koh;Seok-Jae Hwang;Jin-Yong Hwang;Jeong Rang Park
    • Journal of Cardiovascular Imaging
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    • 제31권2호
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    • pp.85-95
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    • 2023
  • BACKGROUND: The prognostic utility of follow-up transthoracic echocardiography (FU-TTE) in patients with hypertrophic cardiomyopathy (HCM) is unclear, specifically in terms of whether changes in echocardiographic parameters in routine FU-TTE parameters are associated with cardiovascular outcomes. METHODS: From 2010 to 2017, 162 patients with HCM were retrospectively enrolled in this study. Using echocardiography, HCM was diagnosed based on morphological criteria. Patients with other diseases that cause cardiac hypertrophy were excluded. TTE parameters at baseline and FU were analyzed. FU-TTE was designated as the last recorded value in patients who did not develop any cardiovascular event or the latest exam before event development. Clinical outcomes were acute heart failure, cardiac death, arrhythmia, ischemic stroke, and cardiogenic syncope. RESULTS: Median interval between the baseline TTE and FU-TTE was 3.3 years. Median clinical FU duration was 4.7 years. Septal trans-mitral velocity/mitral annular tissue Doppler velocity (E/e'), tricuspid regurgitation velocity, left ventricular ejection fraction (LVEF), and left atrial volume index (LAVI) at baseline were recorded. LVEF, LAVI, and E/e' values were associated with poor outcomes. However, no delta values predicted HCM-related cardiovascular outcomes. Logistic regression models incorporating changes in TTE parameters had no significant findings. Baseline LAVI was the best predictor of a poor prognosis. In survival analysis, an already enlarged or increased size LAVI was associated with poorer clinical outcomes. CONCLUSIONS: Changes in echocardiographic parameters extracted from TTE did not assist in predicting clinical outcomes. Cross-sectionally evaluated TTE parameters were superior to changes in TTE parameters between baseline and FU at predicting cardiovascular events.

국내 자생 엽채류 번행초의 우수 유전자원 기초 선발 (Preliminary screening of leafy vegetable New Zealand spinaches (Tetragonia tetragonioides) native to Korea)

  • 김인경;이가연;김성기;김병운;최원영;이긍주
    • 농업과학연구
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    • 제39권4호
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    • pp.515-523
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    • 2012
  • Recent development and enlargement of reclaimed lands along the sea shores required to explore alternatives to existing crops, which are suitable to grow well and to declare higher profits. The objectives of this study were to investigate yield-related parameters for development of new leafy vegetables, and to screen some candidates among New Zealand spinach genotypes which were collected in Korea. Initially all the collected genotypes were grown for 7 weeks in a greenhouse of the experiment field in Chungnam National University, and then transplanted into the field to measure morphological or physiological parameters (plant height, branch number, stem diameter, chlorophyll content, and maximum canopy diameter), and yield-related parameters (leaf number, leaf length, leaf width, fresh weight and dry weight). Those parameters were quantitatively measured at 1, 5 or 9 weeks after transplanting (WAT). Parameters exhibiting statistically significant difference among the accessions were plant height, branch number, maximum canopy diameter, chlorophyll content, and leaf length. In contrast to highly correlated parameters with fresh and dry weight obtained in salt-affected soil in the earlier report, fresh weight was correlated significantly with leaf length (r=0.72), leaf width (r=0.64), and canopy diameter(r=0.66), while dry weight was correlated significantly with plant height (r=0.46), leaf length (r=0.72), leaf width (r=0.73), fresh weight (r=0.79), chlorophyll content (r=0.47), and canopy diameter (r=0.87). Based on the significantly correlated with yield parameters, the candidate accessions which were ranked in top statistical groups include CNU06A01, CNU06A13, CNU06A26, CNU06A35, CNU06A38, and CNU06A55. In order to be cultivated in reclaimed lands, it is necessary to screen out salt tolerant accessions among the above high-yielding genotypes.

RAPD 분석법을 이용한 산삼, 웅담, 녹용 등의 한약재 판별연구 (Identification study of rare and high-priced natural products used for oriental medicine by RAPD analysis)

  • 조동욱
    • 한국한의학연구원논문집
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    • 제1권1호
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    • pp.471-476
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    • 1995
  • Natural products used for oriental medicine often come from various geographical sources, after several different distribution channels. Therefore some form of quality control procedure is required to safeguard naturl products for prescriptions purposes. To achieve this, systematic apprroaches such as morphological examination, microscopic analysis of powdered herbs and chemical analysis can be carried out. However, to ensure absolute criteria for quality assurance of natural products, DNA fingerprinting method such as RAPD(Random amplified polymorphism DNA) analysis can be used for authentication of natural products for authenticatin of natural products. In this study, warious oligonucleotide primers will be synthesized for the detection of RAPD markers and also parameters of affecting PCR(Polymerase Chain Reaction) in the detection of RAPD markers of rare and high-priced natural products will be studied with genomic DNA of chosen samples.

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프랙탈 차원을 이용한 모음인식 (Vowel Recognition Using the Fractal Dimensioin)

  • 최철영
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1994년도 제11회 음성통신 및 신호처리 워크샵 논문집 (SCAS 11권 1호)
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    • pp.364-367
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    • 1994
  • In this paper, we carried out some experiments on the Korean vowel recognition using the fractal dimension of the speech signals. We chose the Mincowski-Bouligand dimensioni as the fractal dimension, and computed it using the morphological covering method. For our experiments, we used both the fractal dimension and the LPC cepstrum which is conventionally known to be one of the best parameters for speech recognition, and examined the usefulness of the fractal dimension. From the vowel recognition experiments under various consonant contexts, we achieved the vowel recognition error rats of 5.6% and 3.2% for the case with only LPC cepstrum and that with both LPC cepstrum and the fractal dimension, respectively. The results indicate that the incorporation of the fractal dimension with LPC cepstrum gies more than 40% reduction in recognition errors, and indicates that the fractal dimension is a useful feature parameter for speech recognition.

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PLD를 이용한 ZnO 박막의 구조적 특성과 표면의 형태에 관한 연구 (The Structural Characteristic and Surface Morphology of ZnO Thin Films by Pulsed Laser Deposition)

  • 김재홍;이경철;이천
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제52권6호
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    • pp.231-234
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    • 2003
  • ZnO thin films on (100) p-type silicon substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266nm. The influence of the deposition parameters, such as oxygen pressure, substrate temperature and laser energy density variation on the properties of the grown film, was studied. The experiments were performed for oxygen gas flow rate of 100~700 sccm and substrate temperatures in the range of 200~$500^{\circ}C$. We investigated the structural and morphological properties of ZnO thin films using X-ray diffraction(XRD), scanning electron microscopy(SEM) and atomic force microscopy(AFM).

Conservation of Multivoltine Silkworm (Bombyx mori L.) Germplasm in India - An Overview

  • Kumaresan, P.;Sinha, R.K.;Mohan, B.;Thangavelu, K.
    • International Journal of Industrial Entomology and Biomaterials
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    • 제9권1호
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    • pp.1-13
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    • 2004
  • Indian multivoltine mulberry silkworm (Bombyx mori L.) strains are poor in silk productivity and fibre quality. However, they are commercially exploited for the past five decades either in the form of pure breeds or cross breeds because of their adaptability to adverse climatic condition and acclimatization to specific regions and seasons. In the present paper conservation strategies of multivoltine silkworm genetic resources are dealt along with detailed information on accessibility of genetic resources, method of genetic resources conservation, characterization of genetic resources for morphological and productivity traits of economic importance. Selection of best ten accessions based on various economic parameters including yarn quality and their scope for future utilization are discussed.

Pharmacognostical Evaluation and Phytochemical Standardization of Abrus precatorius L. Seeds

  • Verma, Durgesh;Tiwari, Shashi Shankar;Srivastava, Sharad;Rawat, A.K.S.
    • Natural Product Sciences
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    • 제17권1호
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    • pp.51-57
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    • 2011
  • The seeds of Abrus precatorius L. (Family- Fabaceae) constitute the drugs Abrus, Gunja, or Ratti in commerce. In the Indian System of Medicine, the seeds are used for sciatica, paralysis, headache, dysentery, diarrhoea, leprosy, ulcer, nervous disorders, alopecia, as well as anti-inflammatory, antidiabetic, antibacterial, antitumor, sexual stimulant and abortifacient. Seeds are poisonous and therefore are used after mitigation. The protein abrin is responsible for the highly toxic properties of seeds. Quantitative HPTLC analysis of the methanolic extract of seeds determined the presence of 0.4018% gallic acid and 0.4009% glycyrrhizin. The present study was undertaken to develop an HPTLC method, as well as ascertain the physico-chemical, morphological and histological parameters to establish the authenticity of A. precatorius seeds.

비젼시스템을 이용한 공구마모 측정기술

  • 남원우;조창연;이종항;이상조
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 추계학술대회 논문집
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    • pp.199-203
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    • 2001
  • It is well know that the interest on the on-line sensing of tool wear is groeing more and more with the aim of controlling machine tools productivity form the point of view of quality and quantity. This paper describes the sensing of the amount of flank wear with vision system. To obtain a proper image He-Ne laser generator is used as the lighting source and obtained image is processed with block processing algorithm and morphological image processing method. By means of this system it is possible to evaluate the parameters of tool wear. Experimental tests performed with this system on an NC lathe have shown good performances here described and discussed.

고분자 첨가제인 난연제로서의 수산화마그네슘계 물질의 합성과 특성 (Synthesis and Characteristics of Magnesium Hydroxide Group Flame Retardant for Polymer Addtives)

  • 이동규;강국현;이진화
    • 한국응용과학기술학회지
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    • 제26권4호
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    • pp.385-393
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    • 2009
  • Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of ${SO_4}^{2-}$ in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to $1050^{\circ}C$. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.