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Analysis of Optimal Sounding Signal Design in OFDM Systems
Jo, Junho,Oh, Janghoon,Choi, Seyeong The Korea Institute of Information and Commucation 2015 Journal of information and communication convergen Vol.13 No.2
We focus on a sounding signal design for single-input single-output orthogonal frequency division multiplexing (SISO-OFDM) systems. We show that the frequency spectrum of an optimum sounding signal has a constant magnitude across the frequency band for the cases with or without Doppler effects. Simulation results show that the designed optimum sounding signal outperforms random sounding signals and that the performance of a maximal-length shift register sequence is indistinguishable from that of the optimum sounding signal.
Unfavorable outcome of a paranasal cosmetic prosthesis caused by dental implants: a case report
Jo Hyunmi,Oh Yeonjin,Jeong Bong-Jin,Jung Junho,Ohe Joo-Young 대한치과이식(임프란트)학회 2020 The Korean Academy of Implant Dentistry Vol.39 No.3
This article presents an unfavorable outcome of a paranasal cosmetic prosthesis, Medpor, which is affected by dental implants. The paper provides treatment insight for oral and maxillofacial specialists. The patients had undergone mandibular set-back surgery combined with both paranasal augmentations using Medpor. In due course, dental implants were placed on the anterior maxilla a few years later. The patient suffered from persistent pain and purulent discharge, but no significant correlation was observed on the panorama and CBCT. Dental implants were inserted near the Medpor for a paranasal augmentation, affecting each other, resulting in clinical symptoms. Medpor, as a radiolucent material, was not visible on dental radiography. Its characteristics of a bony-like texture and color could mislead dentists to misjudge a bony structure clinically. Therefore, the dental implant fixtures were inserted near the Medpor. The Medpors on the affected area were infected, requiring it to be surgically removed. This suggests that both dental implants and Medpors failed. A comprehensive evaluation of patient history and strategic presurgical planning should be obtained to avoid an inappropriate consequence of grafting.
Jo, Minsang,Park, Sanghyuk,Song, Junho,Kwon, Kyungjung Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.764 No.-
<P><B>Abstract</B></P> <P>Resynthesized cathode active materials from the leaching solution of spent lithium ion batteries can contain a Cu impurity element, which is anode current collector. There is also a lack of consensus on the effects of Cu doping element/impurity in cathode active materials. We synthesize LiNi<SUB>1/3</SUB>Mn<SUB>1/3</SUB>Co<SUB>1/3</SUB>O<SUB>2</SUB> (NCM) active materials with the addition of Cu. The effects of Cu on the electrochemical properties (initial charge/discharge capacity, rate capability, and cycleability) of NCM cathode are investigated under different experimental conditions such as cutoff voltage and temperature. Initial charge/discharge capacities gradually decrease and rate capability deteriorates with increasing the Cu content. The enhanced capacity retention of NCM with a certain range (∼1.5 mol%) of Cu content is obtained. A decline in the discharge capacity of the full cell, where graphite is adopted as anode active material, is more prominent than that of the half cell. Whereas the graphite anode before cycling contains no metal component on the surface, the surface composition on the graphite anode after cycling is dominated mostly by Cu, followed by Mn, with a negligible amount of Co and Ni. Cu in the NCM cathode dissolves and the dissolved Cu ions are deposited on the graphite surface, which would deteriorate the full cell performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of Cu in NiCoMn oxide on its Li ion battery performance are investigated. </LI> <LI> Capacity and rate capability of NiCoMn oxide deteriorate by Cu addition. </LI> <LI> Cycleability is somewhat improved with a certain range of Cu content. </LI> <LI> Cu dissolves from NiCoMn oxide and transfers to graphite anode. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>