Effects of Si on the Microstructure and Work Hardening Behavior of Fe‒17Mn‒1.1C‒xSi High Manganese Steels

Renlong Xiong,Yi Liu,Haitao Si,Huabei Peng,Shanling Wang,Binhan Sun,Hanxin Chen,Hyoung Seop Kim,Yuhua Wen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In order to improve the work hardening capacity under low stresses and the yield strength of conventional Hadfield steels, theeffects of Si on the microstructure and work hardening behavior of the Fe‒17Mn‒1.1C‒xSi steels under both quasi-statictensile and low load impact are investigated. It is shown that the increase of the Si contents remarkably improves the yieldstrength by 36 MPa per 1 wt% Si in the investigated steel system without significant sacrifice of ductility. The decreasingeffect of Si on the stacking fault energy is strongly affected by carbon, although the variation of carbon content was small. This led to the unexpected similar stacking fault energy between 1Si and 2Si steel. With the increase of the Si contents forthe steels, the critical strain for the onset of mechanical twinning was lowered, which was controlled by the cooperationbetween the stacking fault energy and solid solution strengthening of Si. This resulted in the earlier initiation of mechanicaltwins and an increase in the twin volume fraction. Therefore, the work hardening capacities under both quasi-static tensileand low load impact tests were enhanced. It was also found that the impact deformation decreased as more mechanical twinsabsorbed the impact energy.

반복적인 경련을 동반한 아이소니아지드(Isoniazid) 중독환자의 치험 1례

이환,오동렬,정시경,김영민,이운정,김세경,이원재,최경호 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Isoniazid(Isonicotinic acid hydrazide) is an antimicrobial drug used since 1952 as a first line agent for the prophylaxis and treatment of tuberculosis. Isoniazid is well known for problems in population having a high prevalence of isoniazid use for prophylaxis or treatment of tuberculosis. But intentional or accidental isoniazid overdose is uncommon. The ingestion of toxic amounts of isoniazid causes recurrent seizures, profound metabolic acidosis, coma and even death. In adults, toxicity can occur with the acute ingestion of as little as 1.5g of isoniazid. Doses larger than 30mg per kg often produce seizures. When ingested in amounts of 80-150mg per kg or more, isoniazid can be rapid fatal. 40-year-old woman having previous pulmonary tuberculosis ingested 7gram of isoniazid(140mg/kg) to attempt suicide approximately 30 minutes prior to visit to our emergency medical center. She had recurrent generalized tonicclonic seizures and metabolic acidosis. We report one patient treated with pyridoxine, which was equivalent to the amount of isoniazid ingested and administered as a intravenous dose and oral dose

응급의료센터의 단기입원치료실 활용경험

최승필,박승현,정시경,박규남,김영민,김세경,이운정,이환 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Overcrowding of emergency department is a serious and growing problem at St. Mary's Hospital. This has motivated the development of short-stay unit(SSU) as an alternative ward to routine hospital admission and ED discharge. In our hospital a SSU begun to admit patients in January 6, 1997. The SSU received 247 patients from the ED during the eight month interval(January 6, 1997 to August 31, 1997). To examine the utilization of the SSU in ED, we retrospectively analyzed 247 patients admitted in SSU from the ED, and compared the average hours per patient with acute gastroenteritis spent in the ED during the 2-month intervals before(July-August 1996) and after(July-August 1997) the establishment of the SSU. The following results were obtained; 1. The total patients consist of EM 92(37.2%), GS 48(19.4%), IM 24(9.7%), PS 21(8.5%), OS 20(8.1%), OBGY 14(5.7%) and others 28(11.3%) 2. The results of EM patients admitted in SSU from ED 1) Sex ratio of male to female was 1:1.1 and the mean age was 37.3±16years 2) In diagnosis, acute gastroenteritis was 29 cases(31.5%), multiple contusion 14 cases(15.2%), drug intoxication 12 cases(13%), limb laceration 6 cases(6.5%), tendon rupture of hand 6 cases(6.5%), and others 19 cases(20.6). 3) Mean length of stay in ED was 9.18 hours. 4) Among 92 patients to the SSU, 79 patients(85.9%) were discharged, 11 patients(11.9%) formally admitted to hospital and 2 patients(2.2%) transferred to otherhospital. The mean hospital stay time of the patients admitted to SSU was 2.6 days. 3. There was a significant reduction in the average stay time spent in the ED by treat-and-releasing patients with acute gastroenteritis after the establishment of the SSU(from 14.65±9.6 to 7.52±5.4 hr/patient, p<0.001). Conclusively, the establishment of the SSU can shorten the average stay time that treat-and-releasing patients spend in the ED, and reduce the number of admitted patients waiting in the ED.

폐부종과 심정지가 발생한 페노바비탈 중독환자

오동렬,이운정,박규남,김세경,김영민,이환,유은영,최경호,정시경 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Phenobarbital is a long-acting barbiturate causing generalized depression of neuronal activity in the brain. Its effect is primarily achieved through enhanced GABA-mediated synaptic inhibition. Its use as an antiepileptic agent was first described in 1912. Before the introduction of phenytoin, phenobarbital is used as sedative-hypnotics. It is used for the treatment of epilepsy and status epilepticus. All barbiturates, including phenobarbital, have a high potential for abuse. They were frequently used for suicide attempts in the past, but they have in large part been replaced by benzodiazepines. The onset of symptoms depends on the drug and the route of administration. Mild to moderate barbiturate intoxication resembles ethanol inebriation with slurred speech, ataxia, and lethargy. Severe acute barbiturate intoxication is life threatening. Early deaths are generally cardiovascular-related. Hypotension, shock, pulmonary edema, and cardiac arrest that occurs with large doses are caused by depression of central sympathetic tone and as well as by direct depression of cardiac contractility. The potentially fatal oral dose of phenobarbital is 6-10g. We describe an 23-year-old woman with pulmonary edema, and cardiac arrest ingestion of 18grams of phenobarbital. She was completely recovered by successful cardiopulmonary resuscitation and homoperfusion. We report a case with literature review.

A novel computer vision-based vibration measurement and coarse-to-fine damage assessment method for truss bridges

Yi-Qing Ni,Wen-Qiang Liu,En-Ze Rui,Lei Yuan,Si-Yi Chen,You-Liang Zheng 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.31 No.4

To assess structural condition in a non-destructive manner, computer vision-based structural health monitoring (SHM) has become a focus. Compared to traditional contact-type sensors, the advantages of computer vision-based measurement systems include lower installation costs and broader measurement areas. In this study, we propose a novel computer vision-based vibration measurement and coarse-to-fine damage assessment method for truss bridges. First, a deep learning model FairMOT is introduced to track the regions of interest (ROIs) that include joints to enhance the automation performance compared with traditional target tracking algorithms. To calculate the displacement of the tracked ROIs accurately, a normalized cross-correlation method is adopted to fine-tune the offset, while the Harris corner matching is utilized to correct the vibration displacement errors caused by the non-parallel between the truss plane and the image plane. Then, based on the advantages of the stochastic damage locating vector (SDLV) and Bayesian inference-based stochastic model updating (BISMU), they are combined to achieve the coarse-to-fine localization of the truss bridge's damaged elements. Finally, the severity quantification of the damaged components is performed by the BI-SMU. The experiment results show that the proposed method can accurately recognize the vibration displacement and evaluate the structural damage.

A Survey of the Geographic Distribution of Ophiocordyceps sinensis

Yi Li,Xiao-Liang Wang,Lei Jiao,Yi Jiang,Hui Li,Si-Ping Jiang,Ngarong Lhosumtseiring,Shen-Zhan Fu,Cai-Hong Dong,Yu Zhan,Yi-Jian Yao 한국미생물학회 2011 The journal of microbiology Vol.49 No.6

Ophiocordyceps sinensis is one of the best known fungi in Traditional Chinese Medicine. Many efforts have been devoted to locating the production areas of this species resulting in various reports; however, its geographic distribution remains incompletely understood. Distribution of O. sinensis at the county level is clarified in this work based on both a literature search and fieldwork. More than 3600 publications related to O. sinensis were investigated, including scientific papers, books, and online information. Herbarium specimens of O. sinensis and field collections made by this research group during the years 2000-2010 were examined to verify the distribution sites. A total of 203 localities for O. sinensis have been found, of which 106 are considered as confirmed distribution sites, 65 as possible distribution sites, 29 as excluded distribution sites and three as suspicious distribution sites. The results show that O. sinensis is confined to the Tibetan Plateau and its surrounding regions, including Tibet, Gansu, Qinghai, Sichuan, and Yunnan provinces in China and in certain areas of the southern flank of the Himalayas, in the countries of Bhutan, India and Nepal, with 3,000 m as the lowest altitude for the distribution. The fungus is distributed from the southernmost site in Yulong Naxi Autonomous County in northwestern Yunnan Province to the northernmost site in the Qilian Mountains in Qilian County, Qinghai Province, and from the east edge of the Tibetan Plateau in Wudu County, Gansu Province to the westernmost site in Uttarakhand, India. The clarification of the geographic distribution of O. sinensis will lay the foundation for conservation and sustainable use of the species.

An Elastic Modulus Developing Model of Fly Ash Concrete under Sustained Load

Si-yi Jia,Ming-hui Liu,Bing Han,Hui-bing Xie 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

This paper focuses on the developing rule of elastic modulus of Fly Ash Concrete (FAC) under sustained load. Mechanism of theaction of sustained load on concrete is discussed and a new model for the elastic modulus of FAC is constructed based on the TriplephaseSpherical Model (TSM). An experiment with three concrete mix designs and five testing groups were conducted. Theexperimental compressive strength and elastic modulus at six different ages were used to calibrate the parameters in the model. Influences of two important parameters (loading age and loading level) in the model were analyzed. Test data confirmed the fact thatelastic modulus for the loaded concrete have a small increment compared to the non-loaded, which is more evident for youngerconcrete, and calculation results showed that the newly constructed model can well predict the elastic modulus of concrete undersustained load. Besides, compared to the loading age, the loading level was proved to be a more important factor in deciding thedevelopment rule of elastic modulus for the loaded concrete.

베이지안 네트워크를 이용한 스마트폰 GPS센서의 효율적인 에너지 관리시스템

이시혁(Si-Hyuk Yi),조성배(Sung-Bae Cho) 한국정보과학회 2011 한국정보과학회 학술발표논문집 Vol.38 No.2B

최근 스마트폰의 사용량이 급증함에 따라 GPS를 이용한 어플리케이션이 널리 보급되고 있다. 그러나 GPS센서는 에너지 소모가 크다는 단점이 있기 때문에 실내에서 불필요하게 사용되는 횟수를 줄인다면 에너지를 절약할 수 있다. 기존연구에서는 GPS사용을 줄이기 위한 방법이나 GPS센서의 사용주기를 조절하는 방법들이 제안되었다. 본 논문에서는 에너지를 적게 소모하면서 높은 신뢰도의 지역정보를 얻기 위해 스마트폰 내장센서를 사용한 베이지안 네트워크의 추론방법을 제안한다. 또한 실제 안드로이드 플랫폼 상에서 실험 및 평가를 수행하여 그 유용성을 입증한다.

디지털 캐릭터 디자인을 위한 캐릭터 분석 모형 -시나리오 분석을 중심으로

이시내 ( Si Nae Yi ),석혜정 ( Hae Jung Suk ),장우진 ( Woo Jin Chang ) 한국디지털영상학회 2009 디지털영상학술지 Vol.6 No.1

연속영상의 시공간 모델 기반 교통사고 탐지시스템

이시혁(Si-Hyuk Yi),조성배(Sung-Bae Cho) 한국정보과학회 2012 한국정보과학회 학술발표논문집 Vol.39 No.2B