• Mass Spectrometry Letters
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• v.12 no.2
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• pp.41-46
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• 2021

Collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD) are the widely used fragmentation technique in mass spectrometry-based proteomics studies. Understanding the fragmentation pattern from the tandem mass spectra using statistical methods helps to implement efficient spectrum analysis algorithms. The study characterizes the frequency of occurrence of multi-charged fragment ions and their neutral loss events of doubly and triply charged peptides in the CID and HCD spectrum. The dependency of the length of the fragment ion on the occurrence of multi-charged fragment ion is characterized here. Study shows that the singly charged fragment ions are generally dominated in the doubly charged peptide spectrum. However, as the length of the product ion increases, the frequency of occurrence of charge 2 fragment ions increases. The y- ions have more tendencies to generate charge 2 fragment ions than b- ions, both in CID and HCD spectrum. The frequency of occurrence of charge 2 fragment ion peaks is prominent upon the dissociation of the triply charged peptides. For triply charged peptides, product ion of higher length occurred in multiple charge states in CID spectrum. The neutral loss peaks mostly exist in charge 2 states in the triply charged peptide spectrum. The b-ions peaks are observed in much less frequency than y-ions in HCD spectrum as the length of the fragment increases. Isotopic peaks are occurred in charge 2 state both in doubly and triply charged peptide's HCD spectrum.

• Geomechanics and Engineering
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• v.28 no.5
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• pp.477-491
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• 2022

In the present study, the effects of thermal loading on the buckling and resonance frequency of graphene platelets (GPL) reinforced nano-composites are examined. Functionally graded (FG) material properties are considered in thickness direction for the thermal responses of the composite. The equivalent material properties are obtained using Halphin-Tsai nano-mechanical model for composite layers. Moreover, the effects of nano-scale sizes are taken into account, employing functionally modified couple stress (FMCS) parameter. In this regard, for the first time, it is demonstrated that at certain values of GPL weight fraction, thermal buckling occurs. In obtaining results of vibrational behavior, both analytical solution and deep neural network (DNN) methods are used. The DNN method needs low computational costs to predict the resonance behavior. A comprehensive parametric study is conducted to indicate the effects of several geometrical, material, and loading conditions on the vibrational and buckling behavior of cylindrical shell structures made of GPL-nanocomposites. It is shown that the effect of temperature change on the occurrence of buckling is vital while it has a negligible impact on the resonance frequency of the structure. Moreover, the size-dependency of the results is demonstrated, and it cannot be neglected in nano-scales.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1633-1635
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• 1999

In this study, we evaluated the dependence of thickness and temperature in the breakdown strength of MDPE and effect of semiconductor. As the result, breakdown strength trend to decrease according to the increase of thickness and temperature. We obtained the result that the breakdown strength was a little lower in the structure of Semi/MDPE than Semi/MDPE/Semi, but breakdown strength of MDPE was greater both of all. The dependency of permittivity, tan ${\delta}$ and conductance on frequency and temperature were investigated. Both of the specimans showed the trend of decreased in permittivity as the temperature increased but increase as the frequency increased.

• Journal of Korean Vacuum Science & Technology
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• v.4 no.4
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• pp.107-111
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• 2000

We extend numerical analysis investigating the waveguide parameter dependency of the two resonant frequencies at the small-signal gain regime in a waveguide free-electron laser to the case that there exists a nonlinear coupling. The properties of the nonlinear interaction between the two resonant waves, one with higher frequency and positive slippage and the another one with lower frequency and negative slippage, are numerically investigated in the high gain regime. The results of numerical work with a set of partial differential equations describing the space and time interaction of the two resonant waves are analyzed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.367-374
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• 2000

This study investigates the effect of hysteretic characteristics to the Inelastic Demand Spectrum (IDS) which was expressed by an acceleration(Sa) and a displacement response spectrum (Sd). Elasto Perfectly Plastic(EPP) model is used in this study and inelastic demand spectrum (Sa vs, Sd) are obtained from a given target ductility ratio. For a given target ductility ratio IDS can be obtained by using nonlinear time history analysis of single degree of system with forth five recorded earthquake ground motions for stiff soil site. The effect EPP model under demand spectrum is investigated by ductility factor and natural frequency. According to the results obtained in this study IDS has dependency on ductility factor and natural frequency.

• Smart Structures and Systems
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• v.25 no.4
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• pp.501-514
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• 2020

This article presents a comprehensive model to investigate a free vibration and resonance frequencies of nanostructure perforated beam element as nano-resonator. Nano-scale size dependency of regular square perforated beam is considered by using nonlocal differential form of Eringen constitutive equation. Equivalent mass, inertia, bending and shear rigidities of perforated beam structure are developed. Kinematic displacement assumptions of both Timoshenko and Euler-Bernoulli are assumed to consider thick and thin beams, respectively. So, this model considers the effect of shear on natural frequencies of perforated nanobeams. Equations of motion for local and nonlocal elastic beam are derived. After that, analytical solutions of frequency equations are deduced as function of nonlocal and perforation parameters. The proposed model is validated and verified with previous works. Parametric studies are performed to illustrate the influence of a long-range atomic interaction, hole perforation size, number of rows of holes and boundary conditions on fundamental frequencies of perforated nanobeams. The proposed model is supportive in designing and production of nanobeam resonator used in nanoelectromechanical systems NEMS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.840-843
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• 2001

In this study, temperature dependency of current gain for AlGaAs/GaAs/GaAs HBT is analytically proposed over the temperature range between 300K and 600K. Energy bandgap, effective mass, intrinsic carrier concentration are considered as temperature dependent parameters. Collector current which is numerically calculated is then analytically expressed to enhance the speed of calculation for current gain. From the results, current gain decreases as the temperature increases. These results will be used to expect the unity current gain frequency f$_{T}$ in conjunction with emitter-base and collector- base capacitances.s.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.324-330
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• 1990

In this study, in order to perform dynamic design of machine tools reasonably and effectively, a method was formulated to be applicable to the damped structures connected by joints having elasticity and damping by using substructure synthesis method. And a nonlinear solution method was proposed and it formulates the nonlinear parts by describing functions and uses the reducing transformation matrix by the substructure synthesis method. The results of frequency response analysis of a machine tool, where an NC lathe was partitioned by three parts of spindle, housing and bed-base part and the nonlinearity of bearing parts between spindle and housing was modelled, showed force dependency of the response.

• Progress in Superconductivity and Cryogenics
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• v.4 no.2
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• pp.63-67
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• 2002

In this study, the performance of the Stirling type orifice Pulse tube refrigerator (OPTR) with a linear compressor was investigated by experiment. The dynamic pressures at three points and a temperature at the cold heat exchanger are measured to explore the dependency of the orifice on the performance of the OPTR. The experimental results show that the opening of the orifice has significant effects on the no load temperature and cool down characteristics. The Pressure amplitude in Pulse tube decrease as the opening of the orifice increase, but the mass flow rate through the orifice and the electric input Power to the compressor increase. The results show that the operating frequency and charging Pressure does not affect on the no load temperature. The pressure amplitude in pulse tube decrease as the operating frequency increase or the charging Pressure decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.556-559
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• 1999

In order to investigate the influence on dielectric characteristic due to physical structural change of specimens, we investigated the frequency and temperature dependency of tan $\delta$ for virgin specimen and mixtured specimens in the temperature range of 25[$^{\circ}C$] ~ 120[$^{\circ}C$], frequency range of 300(mv) ~ 1500[mV] An experimenatal specimen is selected as Low Liner Density Polyethylene (LLDPE) and Ethylene Vinyl Acetate(EVA) (thickness 200[$\mu$m]) produced by mixture ratio of 50:50, 60:40, 70:30 and 80:20. From the results of XRD it can be confirmed that the peak of LLDPE and EVA made by mixture ratio of 70:30 at 2$\theta$= 21.4$^{\circ}$is higher and the peak made by amorphous contribution at 2$\theta$= 19.5[$^{\circ}$] is almostly constant without no concern.