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A Study on the Vibration Characteristics of Light Truck Chassis Frame
Hyungjun Noh(노형준),Junbok Ko(고준복),Jinmoo Park(박진무) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In this study, the impact excitation experiment was performed to investigate the dynamic behavior of the frame using the actual chassis frame of 1ton commercial truck. Also the finite element analysis was accomplished using the commercial finite element package program, ABAQUS version 5.8. By comparing the experimental value and the analytical value, the validity of finite element model was verified. Also, the model experiment was carried out by manufacturing reduced size 1/2 of the actual model and unlike the proceeded experiment, the rubber band was used to create boundary condition and accomplished the vibration experiment. Also the change in vibration characteristic was observed which depended upon member's shape of the frame. The result showed that the different vibration characteristic was indicated when the side member and cross member were in shape of channel or box.
180nm CMOS를 이용한 5G FR1 밴드 광대역 저잡음증폭기 설계
노태림(Taerim Noh),강동휘(Donghwi Kang),김형준(Hyungjun Kim),김수현(Suhyun Kim),이옥구(Ockgoo Lee) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.11
This paper presents a broadband low noise amplifier(LNA) that can be implemented as onchip in FR1 band for next-generation 5G wireless mobile communication. Broadband characteristic is obtained through dual resonance of 1st stage and inter-stage without additional inductor and capacitor and broadband high order LC output matching. In the case of double resonance, the short/open of each stage impedance changes for each frequency band and resonates. Then S(1,1) is less than -10 dB in the operating area. In the case of broadband high order LC output matching, the existing LC filter is modified to as a high order. Simulated result of the proposed LNA represents 2.38~5.12 GHz bandwidth, 26.8 dB peak gain. And Noise Figure is 0.88~2.86 dB, OP1dB is 2.95 dBm at 4.25 GHz and IIP3 is -12.1 dBm at 3.25 GHz. It was confirmed that it has a gain of more than 20 dB in the operating band of the FR1 band and operates as a broadband.
Eunae Yoo,Hyungjun Noh,Jeong-Seob Moon,Jae-Eun Lee,Sookyeong Lee,Sojeong Hwang,Yeong-Jee Kim 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
Safflower (Carthamus tinctorius L.) is known as an oil seed crop originated from southern Asia. Chemical components of safflower have been reported such as phenolic acids, flavonoids, quinochalcones and others. It is vastly utilized in various medical conditions and used for flavoring and coloring purpose. Thus, we examined the amount of total phenolic contents (TPC) and investigated the relation between morphological characters with the TPC in 210 accessions from RDA genebank, Korea. TPC was estimated with Folin-Ciocalteu colorimetric assay. Variations in TPC were evaluated from 21.9 to 147 ㎍ GAE/mg dried extract (DE). Correlation showed there were significant inverse correlations of TPC with leaf width and length while others were not related with TPC. The red color of flower had the lowest range of TPC. The maximum and minimum of TPC was all in the yellow color of flower. Biplot analysis revealed that the positive contributors of Dim1 were leaf width, length, flowering and weight of 100 seeds. Meanwhile, Dim2 was mostly contributed by ripening stage. Accessions K185021 containing high TPC could be used for further research in developing new varieties and functional products.
Ye, Fangmin,Noh, Hyungjun,Lee, Jinhong,Lee, Hongkyung,Kim, Hee-Tak The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.15
<P>The carbothermal conversion of Li2SO4 provides a cost-effective strategy to fabricate high-capacity Li2S cathodes; however, Li2S cathodes derived from Li2SO4 at high temperatures (>800 °C), having high crystallinity and large crystal size, result in a low utilization of Li2S. Here, we report Li2SO4/poly(vinyl alcohol)-derived Li2S/carbon nanocomposite (Li2S@C) strips at a record low temperature of 635 °C. These Li2S@C nanocomposite strips as a cathode show a low initial activation potential (2.63 V), a high initial discharge capacity (805 mA h g<SUP>−1</SUP> Li2S) and a high cycling stability (0.2C and 1C). These improved results could be ascribed to the nano-sized Li2S particles as well as their low crystallinity due to the PVA-induced carbon network and the low conversion temperature, respectively. An XPS analysis reveals that the CC and CO bonds derived from the carbonization of PVA can promote the conversion of Li2SO4 at such a low temperature.</P>
Song, Jongchan,Noh, Hyungjun,Lee, Jinhong,Nah, In-Wook,Cho, Won-Il,Kim, Hee-Tak Elsevier 2016 Journal of Power Sources Vol.332 No.-
<P><B>Abstract</B></P> <P>Polysulfide (PS) shuttle, which is one of the critical problems that need to be addressed for realizing lithium sulfur batteries, can be suppressed by confining PSs within microporous or mesoporous templates. However, PS dissolution through the external opening of the templates has to be further prevented. In this work, a poly (3,4-ethylenedioxythiophene) (PEDOT) layer is formed in situ on the CMK-3/S cathode by inducing the electro-oxidative polymerization of the EDOT monomer included in electrolytes during pre-charging. The PEDOT layer covering the external cathode surface functions as a PS blocking layer, which suppresses the PS shuttle and, thus, improves the cycling stability. The spectroscopic analysis indicates that the PEDOT layer reduces the decomposition of the electrolyte by preventing any reaction between the active PS species and electrolytes. Therefore, the in situ formation of the PS blocking layer from the electrolyte additive provides a simple and effective method to improve the cycling stability of lithium sulfur batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A Poly (3,4-ethylenedioxythiophene) (PEDOT) was formed in situ on sulfur electrode. </LI> <LI> A pre-charging step induced the electro-oxidative polymerization of EDOT. </LI> <LI> The PEDOT layer suppressed polysulfide shuttle and electrolyte decomposition. </LI> <LI> The cyclability of Li-S battery was improved by the in situ formed PEDOT layer. </LI> </UL> </P>
Polysulfide rejection layer from alpha-lipoic acid for high performance lithium-sulfur battery
Song, Jongchan,Noh, Hyungjun,Lee, Hongkyung,Lee, Je-Nam,Lee, Dong Jin,Lee, Yunju,Kim, Chul Hwan,Lee, Yong Min,Park, Jung-Ki,Kim, Hee-Tak The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.1
<P>The polysulfide shuttle has been an impediment to the development of lithium-sulfur batteries with high capacity and cycling stability. Here, we report a new strategy to remedy the problem that uses alpha-lipoic acid (ALA) as an electrolyte additive to form a polysulfide rejection layer on the cathode surface<I>via</I>the electrochemical and chemical polymerization of ALA and a stable solid electrolyte interface (SEI) layer on the Li metal anode during the first discharge. The poly(ALA) layer formed<I>in situ</I>effectively prevents the polysulfide shuttle and consequently enhances the discharge capacity and cycling stability, owing to the Donnan potential developed between the polysulfide-concentrated cathode and the fixed negative charge-concentrated poly(ALA) layer. Also, the SEI layer additionally prevents the chemical reaction of the polysulfide and Li metal anode. The approach, based on the double effect, encompasses a new scientific strategy and provides a practical methodology for high performance lithium-sulfur batteries.</P>
고준복(Junbok Ko),노형준(Hyungjun Noh),박진무(Jinmoo Park) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Recently, it is very important to reduce noise and vibration for improving ride comfort in a passenger car as it is being advanced. Natural frequency and mode shape of a tire for passenger car are very important factor in anticipating ride comfort and reducing noise & vibration. Natural frequency and mode shape are specially required for researching transmission of vibration from a tire to axle. In this study, thus, Modal Test and Finite element analysis are carried out for determining the vibration characteristics of a tire under the fixed axle and inflation pressure 32 psi. The FEM model is verified against simulations and experiments. Also the relationship between vibration characteristics and variable (variation of inflation pressure, depth of groove pattern, width of tread) is analyzed by using Finite element analysis.