OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Ganbaatar Nandintsetseg” ,找到相关结果约3条。
The Finite-Precision Numerical Effects Analysis of Infinite Impulse Response  [PDF]
Ganbaatar Nandintsetseg, Xiang-E Sun
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1104719
This paper mainly uses the MATLAB software to design IIR digital filter with the amplitude frequency characteristic method and zero-pole method, and then analyzes the effect of coefficient quantization and quantization effects in IIR digital filter arithmetic. It is that we can use the software to draw some pictures. These pictures can show coefficient system function of IIR digital filter with a certain length to quantify the zero pole after the system distribution, frequency response, after quantizing the coefficients under the direct, parallel and cascade structures, as well as the limit cycle oscillation and the overflow oscillation of fixed-point operation in the quantization effect of operation are drawn.
Antioxidant Constituents of Cotoneaster melanocarpus Lodd.
Veronika M. D. Holzer,Agnieszka D. Lower-Nedza,Myagmar Nandintsetseg,Javzan Batkhuu,Adelheid H. Brantner
Antioxidants , 2013, DOI: 10.3390/antiox2040265
Abstract: The aim of this study was the evaluation of the antioxidant capacity of Cotoneaster melanocarpus Lodd. and the identification of antioxidant active constituents of this plant. C. melanocarpus Lodd. is a shrub indigenous to Mongolia and used in Traditional Mongolian Medicine as a styptic. Before extraction, the plant material was separated into three parts: young sterile shoots, older stems and leaves. All these parts were extracted with water, methanol, ethyl acetate, dichloromethane and hexane, successively. The methanolic extract of the sterile shoots showed the highest antioxidant activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay (IC 50 30.91 ± 2.97 μg/mL). This active extract was further analyzed with chromatographic methods. TLC fingerprinting and HPLC indicated the presence of the flavonol glycosides quercetin-3- O-rutinoside (rutin), quercetin-3- O-galactoside (hyperoside) and quercetin-3- O-glucoside (isoquercetin), ursolic acid as well as chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid. The findings were substantiated with LC-MS. All identified compounds have antioxidant properties and therefore contribute to the radical scavenging activity of the whole plant.
Surface Force Analysis of Pyrite (FeS2): Its Reactivity to Amino Acid Adsorption  [PDF]
Narangerel Ganbaatar, Nina Matsuzaki, Yuya Nakazawa, Rehana Afrin, Masashi Aono, Taka-aki Yano, Tomohiro Hayashi, Masahiko Hara
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.67018
Abstract: It is well known that mineral surfaces play an important role as catalysts for abiotic polymerization of amino acids to form peptides, which are the main components of the first self-replicating system. Understanding the mechanism behind the adsorption of simple amino acids on mineral surfaces is a topic of great interest not only in field of prebiotic evolution and but also in many other branches of material sciences. Various clay minerals have been suggested for studying how organic molecules were first synthesized in a prebiotic “inorganic” environment. Among them, pyrite (FeS2) is one of the most potential minerals as it possesses a highly reactive surface to drive molecular adsorption in prebiotic chemistry reactions. Recent theoretical experiments suggest that amino acids are adsorbed on the pyrite surface depending on its surface structures. However, these results have not been tested experimentally, and the exact mechanism of the specific interactions on this mineral has not been fully resolved yet at the molecular level. In this work, through quantitative force analysis with atomic force microscope (AFM) in which a single amino acid residue was mounted on the tip apex of AFM probe, we were able to find the reaction sites and study the interaction forces between the amino acid and the pyrite surface. Our results of Raman spectroscopic studies and force measurements with a well-designed AFM probe demonstrated for the first time that pyrite provided higher adsorption probabilities of amino acid residues for the chemical reactions at surfaces.

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