Tuning the Microstructure and Mechanical Properties of Cold Sprayed Equiatomic CoCrFeMnNi High-Entropy Alloy Coating Layer

Ji‑Eun Ahn,Young‑Kyun Kim,Sang‑Hoon Yoon,Kee‑Ahn Lee 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

An equiatomic CoCrFeMnNi high entropy alloy (HEA) coating layer was prepared via a cold spray (CS) process. In orderto control the microstructure and nano-indentation properties of the CS HEA, heat treatments were employed. CS HEAcoating layer showed a heterogeneous microstructure where ultra-fine grains were formed at the particle interfaces, whilecoarse grains were formed inside the particles. Furthermore, deformation twins (DTs) were also formed inside the particlesdue to severe plastic deformation (SPD) in each particle generated during the CS deposition. For the 550 °C heat treatment(HT), fine Cr-rich precipitates were additionally formed at the grain boundary and particle boundary. By contrast, recrystallizationoccurred during 850 °C HT, while the size of the Cr-rich precipitate increased. The nano-indentation hardness ofthe CS HEA coating layer was 10.9 GPa, which was ~ 3 times higher than that of the conventional cast HEA. The superiorhardness of the CS HEA might has been enabled due to the combination of the high dislocation density, DTs, and ultra-finegrains. Based on the results above, the strategy to control the microstructure and mechanical properties through HT of theequiatomic CoCrFeMnNi HEA coating layer prepared via the CS process has been discussed.

울증(鬱證)환자에게 용서프로그램을 활용한 오지상승요법(五志相勝療法)을 시행하여 호전된 1례

이상언 ( Sang Eon Lee ),노동진 ( Dong Jin No ),박장호 ( Jang Ho Park ),이고은 ( Go Eun Lee ),박인숙 ( In Sook Park ),류영수 ( Yeong Su Lyu ),안민섭 ( Min Seob Ahn ),정지호 ( Ji Ho Jung ) 대한한방신경정신과학회 2010 동의신경정신과학회지 Vol.21 No.2

Yuzheng(鬱證) comes from obstruction of qi by stress. The patient has depressed mood, irritable sign, chest discomfort, costal pain, angry state or some strange feeling on the throat. Oh-Ji-Sang-Seung(五志相勝) therapy is base on the theory of interrelation in five elements in oriental medicine. The contents of Oh-Ji-Sang-Seung(五志相勝) therapy include five subjugations of five emotions. Anxiety subjugates fear(思勝恐), fear subjugates joy(恐勝喜), joy subjugates pity(喜勝悲), pity subjugates anger(悲勝怒), and anger subjugates anxiety(怒勝思). Forgiveness program is a kind of psychological therapies to decrease the degree of anger and it is included in Oh-Ji-Sang-Seung(五志相勝) therapy. In this case, a female patient, 50 years old, who suffered from Yuzheng(鬱證) with chest discomfort, irritable sign, easily angry state, depressed mood, hot flush, insomnia. We used Oh-Ji-Sang-Seung(五志相勝) therapy besides herbal medication, acupuncture to her condition got improved. Therefore we reported it for the treatment.

Faster algorithms for growing prioritized disks and rectangles

Ahn, Hee-Kap,Bae, Sang Won,Choi, Jongmin,Korman, Matias,Mulzer, Wolfgang,Oh, Eunjin,Park, Ji-won,van Renssen, André,Vigneron, Antoine Elsevier 2019 Computational geometry Vol.80 No.-

<P><B>Abstract</B></P> <P>Motivated by map labeling, Funke, Krumpe, and Storandt [IWOCA 2016] introduced the following problem: we are given a sequence of <I>n</I> disks in the plane. Initially, all disks have radius 0, and they grow at constant, but possibly different, speeds. Whenever two disks touch, the one with the higher index disappears. The goal is to determine the elimination order, i.e., the order in which the disks disappear. We provide the first general subquadratic algorithm for this problem. Our solution extends to other shapes (e.g., rectangles), and it works in any fixed dimension.</P> <P>We also describe an alternative algorithm that is based on quadtrees. Its running time is O ( n ( log ⁡ n + min ⁡ { log ⁡ Δ , log ⁡ Φ } ) ) , where Δ is the ratio of the fastest and the slowest growth rate and Φ is the ratio of the largest and the smallest distance between two disk centers. This improves the running times of previous algorithms by Funke, Krumpe, and Storandt [IWOCA 2016], Bahrdt et al. [ALENEX 2017], and Funke and Storandt [EuroCG 2017].</P> <P>Finally, we give an Ω ( n log ⁡ n ) lower bound, showing that our quadtree algorithms are almost tight.</P>

Patterns of care for patients with nasopharyngeal carcinoma (KROG 11-06) in South Korea

Sung, Soo Yoon,Kang, Min Kyu,Kay, Chul Seung,Keum, Ki Chang,Kim, Sung Hwan,Kim, Yeon-Sil,Kim, Won Taek,Kim, Ji-Yoon,Kim, Jin-Hee,Moon, Sung Ho,Ahn, Yong Chan,Oh, Young Taek,Wu, Hong-Gyun,Lee, Chang-Ge The Korean Society for Radiation Oncology 2015 Radiation Oncology Journal Vol.33 No.3

Purpose: To investigate the patterns of care for patients with nasopharyngeal carcinoma (NPC) in South Korea. Materials and Methods: A multi-institutional retrospective study was performed (Korean Radiation Oncology Group [KROG] 11-06) on a total of 1,445 patients from 15 institutions. Results: Of the 1,445 patients, more than half were stages III (39.9%) and IV (35.8%). In addition to patterns of care, we also investigated trends over time with the periods 1988-1993, 1994-2002, and 2003-2011. The frequencies of magnetic resonance imaging and positron emission tomography-computed tomography were markedly increased in the third period compared to previous 2 periods. Concurrent chemoradiation (CCRT) was performed on 894 patients (61.9%), neoadjuvant chemotherapy on 468 patients (32.4%), and adjuvant chemotherapy on 366 patients (25.3%). Of stage II-IV patients, CCRT performed on 78.8% in 2003-2011 compared to 15.0% in 1988-1993. For patients treated with CCRT, cisplatin was the most commonly used agent in 81.3% of patients. Over the periods of time, commonly used radiotherapy (RT) techniques were changed from 2-dimensional RT (1988-1993, 92.5%) to 3-dimensional RT (2003-2011, 35.5%) or intensity-modulated RT (IMRT; 2003-2011, 56.5%). Median RT doses given to primary tumors, high-risk lymphatics, and low-risk lymphatics were 70.0 Gy, 58.1 Gy, and 48.0 Gy, respectively. Adoption of IMRT increased the dose per fraction and escalated total radiation dose. Conclusion: Assessment of the patterns of care for NPC patients in South Korea demonstrated that management for NPC including diagnostic imaging, treatment regimen, RT techniques and dose schedule, advanced in accordance with the international guidelines.

OCT 광학기기의 레진 컴파짓 수복평가의 응용

Sang Mi Jeon,Young Hee Lee,Hyeong Joon Ji,Hye Joung Cho,Seo Jin Kim,Hye Eun Kim,SUN QIAOCHU,Kyu Hyeon Ahn,Hong Ran Choi,Ok Joon Kim 대한구강악안면병리학회 2016 대한구강악안면병리학회지 Vol.40 No.4

Composite resins are developed as restorative materials to improve esthetics and mechanical properties. To improve the physical properties of resin material, resin filler have to be added. However, no imaging method is adopted for resin filler distribution. Optical coherence tomography (OCT) is a optical imaging technique to delineate microscopic structures within biological tissue. The OCT application to dental composites resin and its filler is not described yet. So, this new and advanced optical method is needed for clinical application for evaluation of dental composite resin. To analyze the spatial distribution of dental composite resin and to evaluate the resin restoration in cavity, frequency domain optical coherence tomography (FD-OCT) was used for their analysis. Resin restored tooth was prepared. For morphological observation, serially sectioned teeth, conventional X-ray taking and micro computed-tomography (CT) images were compared with OCT images. The experiment has done to evaluate the success of the resin restoration using 3 dimensional structure OCT image. In this research, OCT is evaluated as a new technique to image resin restoration. The evaluation of resin restored tooth was performed by OCT. Inappropriate restoration such as marginal adaptation, large porosities, internal integrity and poor contour could be detected. Resin filler also could be checked by OCT. The distribution, number, regularity and size of resin filler can be differentiated from several commercial products. Considering the characteristics of the OCT, it can be used to evaluate the defects of resin restoration, resin filler distribution, and internal integrity between resin material and tooth structure. The OCT can be considered to be a new and advanced method for the evaluation of resin restorations.

ORIGINAL ARTICLE : Studies of Vegetation Structure Analysis and Vegetation Transition over 25 years of Evergreen Broad-leaved Forest in Hong-Do Island

( Sung Je Lee ),( Ji Tae Kim ),( Young Hee Ahn ) 한국환경과학회 2014 한국환경과학회지 Vol.23 No.3

This study aims at classifying and interpreting on the vegetation structure and the vegetation transition over 25 years (between 1986 and 2010), and the correlation with the change of some conditions (the vegetation height and coverage on each layer and the climate factors as WI, CI, mean annual temperature, mean annual total precipitation etc.) in the Evergreen Broad-Leaved Forest,, Hong-Do island. The EBLF is classified into five units of vegetation (Hedera rhombea-Machilus thunbergii community (M-M comm.), Castanopsis sieboldii forest (Machilus japonica-Castanopsis sieboldii community; Raphiolepis indica var. umbellata-C. sieboldii community), community (Qa comm.), Carpinus turczaninovii community (Ct comm.), Camellia japonica stand (Cj stand)). The vegetation transition by CCA had high correlation with the height and coverage on each layer and the climate factors, and it did the succession (transition) that the M-M comm. (2010) from Mallotus japonicus community·Machilus thunbergii community·Carpinus coreana community (Cc comm.)·Aucuba japonica community (Aj comm.)·Trachelos permum asiaticum var. intermedium-Quercus acuta community (TQ comm.) (1986), the communities of C. sieboldii forest (2010) from Aj comm.·TQ comm.·Raphiolepis umbellata-Camellia japonica community (RC comm.) (1986), the Qa comm. (2010) from Ardisia japonica-Castanopsis sieboldii community (AC comm.) and TQ comm. (1986), the Ct comm. (2010) from Cc comm.·RC comm.·Aj comm.·Quercus serrata community and the Cj stand (2010) from AC comm. (1986). the height and coverage on each layer are also changed.

A Shared Compliant Control Scheme based on Internal Model Control

Sung-Ho Ahn,Jae-Hyun Jin,Byung-Suk Park,Ji-Sup Yoon 제어로봇시스템학회 2003 제어로봇시스템학회 국제학술대회 논문집 Vol.2003 No.10

Self-Supplied Nano-Fusing and Transferring Metal Nanostructures via Surface Oxide Reduction

Ahn, Jaeho,Seo, Ji-Won,Kim, Jong Yun,Lee, Jaemin,Cho, Changsoon,Kang, Juhoon,Choi, Sung-Yool,Lee, Jung-Yong American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.2

<P>Here, we demonstrate that chemical reduction of oxide layers on metal nanostructures fuses junctions at nanoscale to improve the opto-electrical performance, and to ensure environmental stability of the interconnected nanonetwork. In addition, the reducing reaction lowers the adhesion force between metal nanostructures and substrates, facilitating the detachment of them from substrates. Detached metal nanonetworks can be easily floated on water and transferred onto various substrates including hydrophobic, floppy, and curved surfaces. Utilizing the detached metal nanostructures, semitransparent organic photovoltaics is fabricated, presenting the applicability of proposed reduction treatment in the device applications.</P>

United Rapid Urease Test Is Superior than Separate Test in Detecting Helicobacter pylori at the Gastric Antrum and Body Specimens

Sung Woon Moon,김태효,Hyeon Sik Kim,Ji-Hyeon Ju,Yeon Jeong Ahn,Hyun Jeong Jang,심상군,김현진,정운태,이옥재 대한소화기내시경학회 2012 Clinical Endoscopy Vol.45 No.4

Background/Aims: The rapid urease test (RUT) is an invasive method to diagnose Helicobacter pylori infection, which relies on the acquisition and examination of gastric antrum and body tissues. We determined and compared the efficacy of RUT when the tissues were examined separately or after being combined. Methods: Two hundred and fourteen patients were included and underwent esophagogastroduodenoscopy from July 2008 to June 2010. The separate test was defined as evaluating the status of infectivity of H. pylori from the antrum and body separately; whereas the united test was carried out putting both tissues from the antrum and body in the same RUT kit. All RUTs were read by a single observer 1, 3,6, 12, and up to 24 hours later. We also got two biopsy specimens stained with hematoxylin and eosin and quantified H. pylori density was calculated on a scale of 0 to 3. Results: Overall positivity for H. pylori was 137 (64%) for the separate test and 148 (69.2%) for the united test (p<0.01). The mean time to a positive test was 3.58 hours for the separate test and 1.69 hours for the united test (p<0.01). The correlation between the time to positive RUT and the severity of histology showed r=+0.556 for the antrum (p<0.01) and r=+0.622 for the body (p<0.01). Conclusions: Combining tissues prior to RUT enhances the detection of H. pylori, as compared with the examination of separate tissues,and shortens the time to develop a positive reaction by approximately 50%. These diagnostic advantages are also accompanied by increased cost-savings.

Comparative Outcomes between abdominal and tumor-sealing Laparoscopic Radical Hysterectomy in cervical cancer : Results from a single surgeon’s experience

( Sang Il Kim ),( Ji Woo Lee ),( Yuyeon Jung ),( Jung Hwan Ahn ),( Ji Geun Yoo ),( Jin Hwi Kim ),( Sung Jong Lee ),( Dong Choon Park ),( Joo Hee Yoon ) 대한산부인과학회 2019 대한산부인과학회 학술대회 Vol.105 No.-

Objective: The objective of this study was to compare risks of recurrence, and survival in a cohort of women undergoing abdominal radical hysterectomy (ARH) versus minimally invasive radical hysterectomy (MRH) using tumor sealing method and vaginal stent for early stage cervical cancer from a single surgeon’s experience. Methods: In this single institution retrospective study, we reviewed medical records of patients who underwent radical hysterectomy for cervical cancer between Jan. 2009 and Dec. 2017. 97 patients with pathologically confirmed 2018 FIGO stage IA1 with LVSI, IA2, IB1 and IB2 cervical cancer were included and were grouped by minimally invasive and abdominal radical hysterectomy. Tumor characteristics, recurrence rate, progression-free survival (PFS), and overall survival (OS) were compared between groups. Results: 97 patients were identified; 14 underwent ARH and 83 underwent MRH. Those who underwent ARH significantly had more tumors that were ≥ 2 cm, < 4cm (71.4% vs 38.5%, p = 0.021). There were no significant differences in recurrence rate (7.1% vs 9.6%, p = 0.769), progression-free survival (PFS) (p = 0.446), or overall survival (OS) (p = 0.685). Among 97 patients, 52 patients were operated by a single surgeon. 9 underwent ARH and 43 underwent MRH. And MRH group is subdivided into tumor sealing group and non-tumor sealing group. In tumor sealing group we created a vaginal cuff and used vaginal stent. There were 1 recurrent case in ARH group (1/9 ; 11.1%) and 3 recurrent cases in MRH group (3/42 ; 7.1%). All 3 recurrent cases were included in non-tumor sealing group. Conclusion: In conclusion, recurrence rate (RR), disease free survival (PFS), and overall survival (OS) of minimally invasive radical hysterectomy (MRH) showed non-inferiority compared to abdominal radical hysterectomy (ARH). And in early stage cervical cancer, tumor sealing method by creating a vaginal cuff and using BUMI manipulator is expected to reduce recurrence after minimally invasive radical hysterectomy.