타액내 뮤신의 농도와 타액 점도의 상관관계 – 정상인에서의 탐색적 연구

Shinhoo Kim,Heewon Jeon,Ji Soo Choi,Byung-Mo Oh,서한길,유병승,Tai Ryoon Han 대한연하장애학회 2020 대한연하장애학회지 Vol.10 No.1

Objective: To analyze the rheological and biochemical properties of saliva in healthy adults. Methods: The subjects were seven healthy young adults (20-39 years). The whole saliva was collected by the spittingmethod between 9:00 am and 12:00 am. Unstimulated saliva was collected first, which was followed by the collectionof stimulated saliva using citric acid was collected. The viscosity was measured using a capillary viscometer to examinethe rheological properties. The MUC5B concentration was analyzed using an enzyme-linked immunosorbentassay (ELISA) for the biochemical properties. Results: Ten and five minutes were required on average for unstimulated saliva and stimulated saliva, respectively, tocollect the minimum amount needed for analysis (8 ml). The flow rate increased from 1.037±0.323 ml/min to 1.823±0.660 ml/min after stimulation (P=0.018). Citric acid stimulation also increased the MUC5B concentration in the salivafrom 3.706±3.575 μg/ml to 6.928±2.03 μg/ml (P=0.028). The viscosity of saliva, however, did not show a significantdifference between with (1.1±0.164 cSt) or without (1.019±0.08 cSt) stimulation (P=0.128). A positive correlationwas observed between the flow rate and MUC5B concentration (Spearman’s rho=0.547, P=0.043). On the otherhand, there was no significant correlation between the MUC5B concentration and viscosity both in the unstimulatedand stimulated saliva (P=0.939 and 0.819, respectively). Conclusion: No significant correlation was observed between the MUC5B concentration and viscosity. Considering thetime required to collect samples, an analysis of the stimulated saliva appears feasible in various research settings. The feasibility of these analysis methods should be examined in a patient population.

전방 경추 골증식체 환자에서 골증식체제거 및경추전방고정술 후 한시적으로 악화된 연하장애: 증례 보고

Shinhoo Kim,Han Gil Seo 대한연하장애학회 2019 대한연하장애학회지 Vol.9 No.2

An anterior cervical osteophyte is one of the causes of dysphagia. Surgical treatment is one of the treatment options available, and previous studies have suggested that it is an immediate and effective treatment. This paper reports a case of temporarily aggravated dysphagia after surgical treatment in a patient with anterior cervical osteophyte. A 75-year-old male complained of dysphagia for one year. A videofluoroscopic swallowing study (VFSS) revealed anterior cervical osteophytes at the C3 and C4 level, which resulted in decreased epiglottic folding and partial obstruction of the bolus passage. After he underwent osteophytectomy and anterior fixation, the post-operativeVFSS showed an aggravation of dysphagia with prevertebral soft tissue edema. The major cause of dysphagia wasattributed to the limitation of movement of the posterior pharyngeal wall and upper esophageal sphincter due tothe increased prevertebral soft tissue thickness. In conclusion, surgery should be considered when a severe dysphagia is persistent after adequate conservative treatment in patients with dysphagia due to anterior cervical osteophytes,and patients at high risk of postoperative dysphagia might require swallowing rehabilitation.

Defects on the Surface of Ti-Doped MgAl ₂ O ₄ Nanophosphor

Lim, Jaehyuk,Kim, Yongseon,Kim, Sungdae,Kim, Youngwoon,Kang, Shinhoo Springer US 2017 NANOSCALE RESEARCH LETTERS Vol.12 No.1

<P>Ti-doped nano MgAl<SUB>2</SUB>O<SUB>4</SUB> for white emission was synthesized by combustion method. Extrinsic Schottky defects, Al vacancies and Ti<SUP>4+</SUP> dopant in Al sites, which are considered to be responsible for bluish-white emission, were observed by STEM on the surface of Ti-doped nano MgAl<SUB>2</SUB>O<SUB>4</SUB> powder. The stabilities of the Schottky defect associates, (Ti<SUB>Al</SUB><SUP>·</SUP>–V<SUB>Al</SUB>′′′)′′, were demonstrated by DFT calculation. The emission behavior was interpreted with these results.</P>

고속 저전력 동작을 위한 개방형 파이프라인 ADC 설계 기법

김신후,김윤정,윤재윤,임신일,강성모,김석기,Kim Shinhoo,Kim Yunjeong,Youn Jaeyoun,Lim Shin-ll,Kang Sung-Mo,Kim Suki 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.1a

본 논문에서는 고속, 저전력 8-비트 ADC를 설계하는 기법들을 제안하였다. 비교적 적은 전력 소모를 가지면서 고속으로 동작 시키기 위해 기존의 파이프라인 구조인 MDAC를 이용한 폐쇄형 구조 대신에 개방형 구조를 채택하였다. 또한 Distributed THA와 캐스캐이드 형태의 구조를 이용하여 높은 샘플링 속도에 최적화 하였다. 제안한 각 단의 크로싱 지점을 판별하는 기법은 증폭기의 개수를 줄일 수 있도록 함으로서 저전력과 좁은 면적의 ADC 구현을 가능하게 하였다. 모의 실험 결과 500-MHz의 샘플링 속도와 1.8V 전원 전압에서 테스트에 필요한 디지털 회로까지 포함, 210mW의 전력을 소비함을 확인 할 수 있었다. 또한 1.2Vpp(Differential) 입력 범위와 200-MHz까지의 입력 주파수에서 8-비트에 가까운 ENOB를 가짐을 볼 수 있었다. 설계된 ADC는 $0.18{\mu}m$ 6-Metal 1-Poly CMOS 공정을 이용, $900{\mu}m{\times}500{\mu}m$의 면적을 차지한다. Some design techniques for high speed and low power pipelined 8-bit ADC are described. To perform high-speed operation with relatively low power consumption, open loop architecture is adopted, while closed loop architecture (with MDAC) is used in conventional pipeline ADC. A distributed track and hold amplifier and a cascading structure are also adopted to increase the sampling rate. To reduce the power consumption and the die area, the number of amplifiers in each stage are optimized and reduced with proposed zero-crossing point generation method. At 500-MHz sampling rate, simulation results show that the power consumption is 210mW including digital logic with 1.8V power supply. And the targeted ADC achieves ENOB of about 8-bit with input frequency up to 200-MHz and input range of 1.2Vpp (Differential). The ADC is designed using a $0.18{\mu}m$ 6-Metal 1-Poly CMOS process and occupies an area of $900{\mu}m{\times}500{\mu}m$

Change in the Surface Microstructure of Ti(C_0.5N_0.5)?20WC?10Ni?10Co Cermets During Sintering in a Nitrogen Atmosphere

Kim, Seongwon,Kang, Shinhoo Wiley (Blackwell Publishing) 2007 JOURNAL OF THE AMERICAN CERAMIC SOCIETY - Vol.90 No.9

Multi-functional colored coating of BaMgAl10O17:Eu phosphors with cobalt-doped Al2O3 thin films

Kim, Yongseon,Kang, Shinhoo Springer-Verlag 2010 APPLIED PHYSICS A MATERIALS SCIENCE AND PROCESSING Vol.98 No.1

Microstructure evolution and mechanical properties of (Ti_0.93W_0.07)C–<i>x</i>WC–20Ni cermets

Kim, Jiwoong,Kang, Shinhoo Elsevier 2011 Materials science & engineering. properties, micro Vol.528 No.7

<P><B>Research highlights</B></P><P>&z.rtrif; (Ti<SUB>0.93</SUB>W<SUB>0.07</SUB>)C–<I>x</I>WC–20Ni cermets have a uniform microstructure compared to conventional cermets. &z.rtrif; As increasing WC addition, the carbide particle size is decreased. &z.rtrif; Comparing to conventional Ti(CN)-based cermets, the solid solution cermets show superior hardness and toughness.</P> <P><B>Abstract</B></P><P>The microstructure and mechanical properties of (Ti<SUB>0.93</SUB>W<SUB>0.07</SUB>)C–<I>x</I>WC–20Ni cermets were investigated to determine the effect of WC addition on the Ti-based solid solution cermet, (Ti<SUB>0.93</SUB>W<SUB>0.07</SUB>)C–20Ni. (Ti<SUB>0.93</SUB>W<SUB>0.07</SUB>)C–20Ni exhibited a homogeneous microstructure with no core–rim structure; however, a core–rim structure was observed with the addition of WC. The carbide size decreased sharply with the addition of 15wt.% WC. After composition, very small coreless carbide (VSCC) particles abruptly emerged in the microstructure. These particles might be formed by homogeneous nucleation during the final stage of sintering and cooling after the outer rim formation period. With increasing WC addition, the hardness remained constant, whereas the toughness decreased. Compared with Ti(CN)-based cermets with similar compositions, the hardness and toughness of (Ti<SUB>0.93</SUB>W<SUB>0.07</SUB>)C–<I>x</I>WC–20Ni cermets exhibited higher values. The refined microstructure of Ti-based solid solution cermets is considered to be responsible for the superior mechanical properties.</P>

Temperature-dependent stable phase domains of Zr–C–N (Zr–ZrC–ZrC_0.96–Zr(C_1−<i>x</i>N_<i>x</i>)−ZrN, <i>x</i> = 0.1–0.9) systems from ab initio calculations and exp

Kim, Jiwoong,Lim, Heejeong,Suh, Yong Jae,Lim, Hyoseon,Kang, Shinhoo Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.692 No.-

<P><B>Abstract</B></P> <P>Despite the importance of ZrC, ZrN, and their intermediate solid solutions, the temperature-dependent phase stability of the Zr–C–N system has not previously been determined precisely. This work reports these phase stabilities determined experimentally and using ab initio calculations within the quasi-harmonic approximation. Special quasi-random structure models and supercell models with random substitution were used to mimic the random atomic distribution of C and N in the sublattice of Zr(C<SUB>1−<I>x</I> </SUB>N<SUB> <I>x</I> </SUB>) solid solutions. The results indicated that volume and high-temperature entropy changes are important to determine the free energy of the solid solutions and that moderate temperatures (∼1500–2000 K) were needed to synthesize Zr(C<SUB>1−<I>x</I> </SUB>N<SUB> <I>x</I> </SUB>) solid solutions. The calculated stable phase domains were then successfully produced. Our results clarify the synthesis and stable phase prediction of the Zr–C–N system under certain external conditions, and they will help broaden the applicability of ZrC, ZrN, and their solid solution phases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermodynamic properties of ZrC, ZrC<SUB>0.96</SUB>, ZrN, Zr(C<SUB>1−x</SUB>N<SUB>x</SUB>) were obtained. </LI> <LI> Stable phase diagrams showed relative temperature-dependent phase stability. </LI> <LI> Harmonic and quasi-harmonic effects of the phases were examined. </LI> <LI> Applicability of the results was examined in practical experimental conditions. </LI> <LI> Results will guide applications, particularly in extreme conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructures and properties of ultrafine grained W–ZrC composites

Kim, Jae-Hee,Park, Choongkwon,Lim, Jaehyuk,Kang, Shinhoo Elsevier 2015 JOURNAL OF ALLOYS AND COMPOUNDS Vol.623 No.-

<P><B>Abstract</B></P> <P>The microstructures and properties of W–ZrC composites prepared in situ were compared with those of conventionally prepared W–ZrC and W–(Zr, W)C. In situ preparation led to an ultrafine microstructure with a homogeneous dispersion of ZrC, while the other composites showed microstructures similar to each other. The composite of W containing 30vol.% (Zr<SUB>0.88</SUB>W<SUB>0.12</SUB>)C showed an excellent flexural strength of ∼1425MPa at 1000°C. It also showed an excellent flexural strain of 0.051 at 1400°C, which was obtained by using a maximum displacement of 2.41mm. Those values have never been reported previously. A similar W composite, in situ W–10vol.% ZrC, demonstrated a flexural strength of 1324MPa and a displacement of 0.9mm under similar conditions. The results of this study are discussed in terms of microstructure and phase stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Various W–<I>x </I>vol.% ZrC (C), (I), and (S) (<I>x </I>=10 or 30) samples were prepared. </LI> <LI> W–ZrC (I) revealed homogeneously dispersed ultrafine grained microstructures. </LI> <LI> W–ZrC (S) showed a mixed form with microstructural features of W–ZrC (C) and (I). </LI> <LI> The W–ZrC (I) and (S) samples were stronger and more ductile than W–ZrC (C). </LI> <LI> The flexural strength of ∼1425MPa at 1000°C was shown by W–30 vol.% (Zr, W)C (S). </LI> </UL> </P>

First principles investigation of temperature and pressure dependent elastic properties of ZrC and ZrN using Debye-Gruneisen theory

Kim, Jiwoong,Kang, Shinhoo Elsevier 2012 JOURNAL OF ALLOYS AND COMPOUNDS Vol.540 No.-