Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Yong‑Ho Kim,Hyo‑Sang Yoo,Jeong‑Han Lee,Ik‑Hyun Oh,Hyun‑Kuk Park,Hyeon‑Taek Son 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pureelements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloypowder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overallpowder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Sialloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification wasclearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformationof particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis ofthe sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remainedthe alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strengthof the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi,Al13Cr4Si4and Al8Cr5phases sintering process, resulting from the improvement of mechanical properties.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

Crotonaldehyde-exposed macrophages induce heme oxygenase-1 expression as an adaptive mechanism

Seung Eun Lee,Hana Yang,Gun Woo Son,Hye Rim Park,Young-Ho Jin,Cheung-Seog Park,Yong Seek Park 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.2

Cigarette smoke represents one of the most significant risk factors for the progression of vascular disease. Exposure to cigarette smoke induces oxidative stress in the vascular system and results in vascular dysfunction. Crotonaldehyde, a highly reactive α,β-unsaturated aldehyde, is a foremost compound of cigarette smoke and a product of endogenous lipid peroxidation. Heme oxygenase-1 (HO-1) expression plays an essential role in cellular defense against environmental insults and represents an adaptive response. Here, we showed the effects of crotonaldehyde on the induction of HO-1 expression in RAW 264.7 macrophages. Crotonaldehyde treatment resulted in significantly increased phosphorylation of p38 mitogenactivated protein kinase (MAPK) and nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Furthermore, treatment with zinc protoporphyrin (ZnPP; the specific HO-1 inhibitor) markedly augmented the death of crotonaldehyde-treated macrophages. In summary, these results highlight the role of the HO-1 upregulation through p38 MAPK-Nrf2 activation in the adaptive response to crotonaldehyde in macrophages.

Eriodictyol Protects Endothelial Cells against Oxidative Stress-Induced Cell Death through Modulating ERK/Nrf2/ARE-Dependent Heme Oxygenase-1 Expression

Lee, Seung Eun,Yang, Hana,Son, Gun Woo,Park, Hye Rim,Park, Cheung-Seog,Jin, Young-Ho,Park, Yong Seek MDPI 2015 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.16 No.7

<P>The pathophysiology of cardiovascular diseases is complex and may involve oxidative stress-related pathways. Eriodictyol is a flavonoid present in citrus fruits that demonstrates anti-inflammatory, anti-cancer, neurotrophic, and antioxidant effects in a range of pathophysiological conditions including vascular diseases. Because oxidative stress plays a key role in the pathogenesis of cardiovascular disease, the present study was designed to verify whether eriodictyol has therapeutic potential. Upregulation of heme oxygenase-1 (HO-1), a phase II detoxifying enzyme, in endothelial cells is considered to be helpful in cardiovascular disease. In this study, human umbilical vein endothelial cells (HUVECs) treated with eriodictyol showed the upregulation of HO-1 through extracellular-regulated kinase (ERK)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathways. Further, eriodictyol treatment provided protection against hydrogen peroxide-provoked cell death. This protective effect was eliminated by treatment with a specific inhibitor of HO-1 and RNA interference-mediated knockdown of HO-1 expression. These data demonstrate that eriodictyol induces ERK/Nrf2/ARE-mediated HO-1 upregulation in human endothelial cells, which is directly associated with its vascular protection against oxidative stress-related endothelial injury, and propose that targeting the upregulation of HO-1 is a promising approach for therapeutic intervention in cardiovascular disease.</P>

Splitter 급전 2소자 원편파 사각 패치 배열안테나의 설계

손태호,강상규,이병수,이용창,백경훈 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.2

Dual-fed circulary polarized microstrip 1 by 2 array antenna is designed and fabricated. To have circular polarization, we applied power splitter with 90 degree phase shifter by the length exetension. A 1 by 2 uniformed array antenna was designed and measured, and compared with theoretical values. The bandwidth characteristic is well coincided with the designed valued, but the center frequency for the GPS 1.575GHz differed sligthly by the reason of the substrate tolerance.

2개 기생소자에 의한 사각형 패치 안테나의 대역폭 확장

손태호,강상규,이병수,이용창,백경훈 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.2

This study is to extend bandwith for the microstrip antenna by parasitic patch devices. Applying two 1/4 wave length parasitic patches both side of microstrip patch, the bandwidth is able to be controlled by the parasitic couplings. We used the Tschebyscheff transformer for multisection matching network to give broadband transformation. It is designed for wireless MMDS CATV antenna and design antenna is fabricated by epoxy substrate of 1.2mm thickness, 4.4 relative permittivity. The theory is well agreed that the results of measurement of S11 has 2.88% band characteristic.

특화거리 조성의 변천과정에서 나타난 Network의 중요성에 관한 연구

손재룡,최준호,이용준,이상호,이경회 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1

Recently, the Specified streets are designated in the many cities. The specified street is formed naturally by gathering the same type of shops in the same street. The purpose of the specified street is to enhance and to make more lively the characteristics of the street. These specified street has the network consisted of elements, namely shop owner, the authorities, the consumers, etc. In the beginning, we examined how specific streets are made and composed in Seoul and Inchun: the street of the culture, the rodeo, and the furniture. As it turned out, the formation of the network organization in the specific streets showed that how much it is important that it impacted managing. The members of network work together for improvement of the street by negotiation and cooperation. In that process, the street scenery is also improved. This network promotes the spontaneous participation of the members of the affair. In the result of that, the effect of the network is a core which is one of the factors managing and improving specific street. A continuous examination of the more study would strengthen the importance of the network in changing specific street construction.

전광 파이버 필터에 관한 연구

손영환,정진호 湖西大學校 工業技術硏究所 2002 工業技術硏究所論文集 Vol.21 No.-

WDM(Wavelength division multiplexing) lightwave communication system of multi-channel requites an Optical filter to extract a signal from a channel. FBG(Fiber Bragg Grating) can be used to extract the specific signal of wavelength channel from the transmission line when many wavelengths are coupled in a multiwavelength transmission line. Also, it has a wide range of application that both improve the quality and reduce the cost of optical networking. In this paper, thus. we propose the FBG filter design using coupled mode theory based on perturbation theory. To analyze output characteristics of FBG and get optimum design data, we use computer simulation and verify through experimentation. The results obtained by experimentation show that the proposed FBG filter fits for DWDM(Dense WDM) system because of wide bandwidth by tunning narrow linewidth.

Genome-wide investigation of a Korean synthetic breed, Woori-Heukdon using the Illumina PorcineSNP60K BeadChip

Yong‑Min Kim,Ha‑Seung Seong,Jung‑Jae Lee,Da‑Hye Son,Jin‑Su Kim,Soo‑Jin Sa,Young‑Sin Kim,Tae‑Jeong Choi,Kyu‑Ho Cho,Joon‑Ki Hong,Jung‑Woo Choi,Eun‑Seok Cho 한국유전학회 2020 Genes & Genomics Vol.42 No.12

Background: Woori-Heukdon (KWH) is a Korean synthetic pig breed generated using Chookjin-Duroc (KCD), Chookjin-Chamdon (KCC), and their crossbreds. Currently, there is a severe lack of studies investigating the Korean breed populations including wild boars (KWB) throughout the genome. Objective: This study was performed to investigate the genetic characteristics of Korean pig populations at the genome-wide level. Methods: Using the SNP dataset derived from genotyped and downloaded datasets using the Illumina PorcineSNP60K BeadChip, we compared the genomes of 532 individuals derived from 23 pig breeds to assess the genetic diversity, inbreeding coefficient, genetic differentiation, and population structure. Results: KWB showed the lowest average expected heterozygosity (HE = 0.1904), while KWH showed the highest genetic diversity (HE = 0.02859) among Korean populations. We verified that the genetic composition of KWH, showing USD of 74.8% and KCC of 25.2% in ADMIXTURE analysis. In population structure analyses, KCC was consistently shown to be separated from other pig populations. In addition, we observed gene flow from Western pigs to a part of Chinese populations. Conclusion: This study showed that Korean native pigs, KCC have genetic differences in comparison with Chinese and Western pigs; despite some historical records and recent genetic studies, we could not find any clear evidence that KCC was significantly influenced by Chinese or Western breeds in this study. We also verified the theoretical genomic composition of KWH at the molecular level in structure analyses. To our knowledge, this is the first genomic study to investigate the genomic characteristics of KWH and KCC.

능력검정에 의한 우량 종봉 선발에 관한 연구

손영익,차용호,최광수 慶北大學校農業科學技術硏究所 2001 慶北大農學誌 Vol.19 No.-

The study was conducted to establish the method of performance test of honeybee queens under Korean environment. Colony performances of apis mellifera were tested based on wintering ability, colony population and honey yield in Sangju, Korea from November, 1999 ∼2000 season were averaged 22.6±2.6kg and 20.1±2.6kg, respectively, showing the decrease of 2.5 ±0.7kg. During 2000∼2001 winter season, the colony weight before wintering was 22.6±2.3kg and was decreased by 2.3± 0.6kg. The number of combs well covered with bees was 13.1± 4.6 as measured on the 22nd of May. 2000 and 16.0± 3.8 on the 21st of May. 2001, respectively. The rate of supering colonies were 50% and 98.5% in 2000 and 2001, respectively. The amount of honey production was 12.7± 8.6kg per colony in 2000, 14.2± 7.6kg per colony with unselected queens and 23.5± 4.9kg per colony with seleceted-tested queens in 2001, which were harvested two times during main nectar flow season of black locust, Robinia peseudoacasia.