Fe-X%Mn-6%Si-9%Cr-5%Ni 합금의 형상기억효과에 미치는 가공열처리의 영향

백승한,전중환,최종술,한중호 연세대학교 산업기술연구소 1994 논문집 Vol.26 No.1

The effect of thermomechanical treatment on the SME(Shape Memory Effect) of Fe-(10∼16)%Mn-6%Si-9%Cr-5%Ni alloys was investigated. The corrosion behaviors of these alloys were also investigated compared with SUS 304 stainless steel and Fe-30%Mn-6%Si shape memory alloy. Through the investigation the Fe-2%Mn-6%Si-9%Cr-5%Ni alloy showed the best SME in as-solution treated state. Training treatment consisting of repetition of cold rolling by 2% at room temperature and subsequent annealing at 650℃ for 10 minutes was performed to improve the SME. The remarkable improvement of SME was obtained at two cycles of training, and then the SME was decreased with further training. This suggests that the extra lattice defects of dislocation and stacking faults introduced by training treatment deteriorates the SME. The Fe-X%Mn-6%Si-9%Cr-5%Ni alloys showed the passive behavior similar to that of SUS 304 stainless steel in 30℃-5% H₂SO₄solution and great improvement in corrosion resistance compared with the Fe-30%Mn-6%Si shape memory alloy.

이중혈류유발 심폐소생술이 심정지를 유발한 개의 단기 생존율에 미치는 영향

황성오,조준휘,강구현,김성환,문중범,이강현,이승환,윤정한,최경훈,홍은석 대한응급의학회 2000 대한응급의학회지 Vol.11 No.3

Background and Objectives: We previously reported that, compared with standard cardiopulmonary resuscitation(S-CPR), better hemodynamic effects could be achieved by simultaneous sterno-thoracic cardiopulmonary resuscitation(SST-CPR) in which we compressed the sternum and constricted the thorax circumferentially during the systolic period by using a device. This study was designed to assess whether SST-CPR, compared with S-CPR, improve the survival rate of dogs with cardiac arrest. Subjects and methods: Twenty-five mongrel dogs(19∼31㎏) were enrolled in this study. After four minutes of ventricular fibrillation induced by an AC current, animals were randomized to resuscitate with either S-CPR(n=13) or SST-CPR(n=12). Epinephrine(1 ㎎) was injected into the right atrium every three minutes after the beginning of CPR. Defibrillation was attempted after 6 minutes of CPR. Standard advanced cardiac life support was started if defibrillation was not successful. Results: SST-CPR resulted in significantly(p<0.001) higher systolic arterial pressure(91±47 vs 47±24 ㎜ Hg), diastolic pressure(43±24 vs 17±10 ㎜ Hg), coronary perfusion pressure(35±25 vs 13±9㎜ Hg), and end tidal CO2 tension(9±4 vs 3±2 ㎜ Hg). Two of 13 animals(15 %) resuscitated with S-CPR and six of 12 animals(50%) resuscitated with SST-CPR survived until 12 hours after cardiac arrest(p<0.05). Donclusion: SST-CPR, compared with S-CPR, improves the short-term survival rate in canine cardiac arrest.

Pocine Adenovirus-3의 E1B Region의 鹽基序列 分析

朴鍾賢,宋載永,李重馥,玄芳勳,安東濬,車相昊,裵用泰,姜永源,Reddy, P S,全茂炯,安壽煥 충남대학교 생물공학연구소 1999 생물공학연구지 Vol.7 No.-

돼지 아데노바이러스(PAV-3). 6618주의 EIB region이 包含되어 있는 map unit 4.0에서 9.7까지의 유전자에 대한 1,984 bp의 염기서열을 決定하였으며, 이 結果를 알려진 여러 아데노바이러스 유전자와 비교하여 다음과 같은 결과를 얻었다. 1. PAV-3의 EIB유전자는 10개의 ORF로 구성되어 있으며, 그 중 아데노바이러스의 단백질과 유사성이 있는 것은 ORF1, ORF2 및 ORF3이었다. ORF1은 Ad41의 19kd 와 BAV-2에서의 EIB ORF2에서의 아미노산의 一致率은 각각 32%와 31%이었다. 2. ORF2는 Ad2 55kd protein과 tupaia adenovirus 44kd protein가 각각 34%로 아미노산 一致率이 가장 높았으며, Ad41의 52kd protein. BAV-3의 EIB ORF3에서도 33%의 一致率을 보였다. 3. ORF1은 61-666 uncleotide (606 bp), ORF 2에서는 429-1,850 uncleotide (1,422 bp)의 부위로 각각 202, 474 a.a로 構成되었으며, 예상되는 분자량은 20 kd와 52 kd이었다. 4. ORF3는 hexon-associated pIX유전자로 추정되며 내부에 1개의 polyadenylation signal(ATAAA)이 1938-1942 uncleotide에 위치하였으며, 이 부위는 TATA box (1937-1942 uncleotide)와 중복되어 존재하였다. Porcine adenovirus type 3 (PAV-3) does not cause severe infection in pigs. Adenovirus has been suggestive of live vaccine vector carrying foreign gene. One of insertion regions is delayed early (EIB) region. However, EIB region of PAV-3 has not been molecularly characterized to date. Nucleotide sequence of EIB of PAV-3 was determined. The EIB region was composed of 1,984 bp and located between 4.0 and 9.7 map units. Three potential open reading frames(ORFs) with low level of homology to other adenoviruses and a polyadenylation signal were identified in the rightward direction of genome. The nucleotide and the predicted amino acid sequences of EIB were compared to those of human and animal adenoviruses. One of the three potential ORFs. ORF1 encoded a polypeptide homologous to bovine adenovirus type 2(BAV-2) ORF2 and human adenovirus type 41(Ad41) 19 kd protein. ORF2 encoded a polypeptide homologous to human adenovirus type 2(Ad2) 55 kd protein, bovine adenovirus type 3(BAV-3) ORF3 and porcine adenovirus type 4(PAV-4) ORF2. The predicted protein of ORF1 had homology to those of Ad41 and BAV-2 with 32 and 31% respectively, whereas the deduced protein of ORF2 had homology to those of Ad2. BAV-3 and PAV-4 with 34, 33 and 29%, respectively.

담낭 방선균증 1예

김형수,정진원,김양수,우준희,송현순,류지소,김명환,김남중 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

저자들은 우상복부 통증과 소화불량을 주소로 내원한 83세 여자 환자에서 국내 최초로 담낭 방선균증을 진단하고 치료 관찰 중으로 이에 문헌고찰과 함께 보고하는 바이다. Actinomycosis is a chronic suppurative and granulomatous disease, characterized by abscess formation, tissue fibrosis, and draining sinuses. Actinomycosis of the gallbladder is very rare and has not yet been reported in Korea. We report a case of actinomycosis of the gallbladder in an 80-year-old women with history of cholelithiasis for 3 years, preoperatively misidentified as gallbladder cancer. Histologic section of the gallbladder showed Gram-positive branching bacilli compatible with actinomyces. After cholecystectomy, the patient received intravenous ampicillin for 4 days, followed by amoxicillin for 4 months thereafter.

Microstructures and Mechanical Properties of Mg-Zn-RE-Ca Casting Alloys

Jun, Joong Hwan,Park, Bong Koo,Kim, Jeong Min,Kim, Ki Tae,Jung, Woon Jae Trans Tech Publications, Ltd. 2006 Materials science forum Vol.510 No.-

<P>Influences of Ca addition on microstructures and mechanical properties at room and elevated temperatures up to 300oC were investigated for ZE41 (Mg-4%Zn-1%Zn)-(0~1.0)%Ca permanent mould casting alloys, based on the results from X-ray diffractometry (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and tensile tests. The microstructure of ZE41 alloy is characterized by dendritic α-(Mg) grains surrounded by Mg7Zn3-based eutectic network phase. The average size of α grains decreases continuously with an increase in Ca content. The Ca-containing ZE41 alloys have Mg7Zn3-(RE)-(Ca) eutectic phase, in which Ca is distributed inhomogeneously owing to its strong segregation power. It is noteworthy that tensile yield strength (YS) for the ZE41 alloy was enhanced with increasing Ca content at all temperatures up to 300oC, which demonstrates that Ca can play a beneficial role in improving its tensile strength at room and elevated temperatures. The ZE41 alloy with 0.5%Ca showed the highest ultimate tensile strength (UTS) at room temperature, but in the range of 175 to 300oC, the higher the Ca content, the greater the UTS. The improved tensile strength of the Ca-containing ZE41 alloy would be caused by the refined α grains and higher thermal stability of the Mg7Zn3-(RE)-(Ca) eutectic phase.</P>

Fabrication and mechanical properties of quasicrystal-reinforced AlMnMm alloys

Jun, Joong-Hwan,Kim, Jeong-Min,Kim, Ki-Tae,Jung, Woon-Jae Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-

<P><B>Abstract</B></P><P>Microstructures and room temperature mechanical properties of quasicrystal-reinforced Al<SUB>94−<I>x</I></SUB>Mn<SUB>6</SUB>Mm<SUB><I>x</I></SUB> (Mm: misch metal, <I>x</I>=0–6at.%) alloys have been studied systematically. Cylindrical rod samples with 3mm in diameter were synthesized by injection-casting into a Cu mould and analyzed by means of X-ray diffractometry, differential scanning calorimetry, optical microscopy and scanning electron microscopy with energy-dispersive X-ray spectrometry. Mechanical properties of the cylindrical rods were measured at room temperature by compression tests. The Al<SUB>94</SUB>Mn<SUB>6</SUB> alloy contains hexagonal-shape particles and long needle-shape Al<SUB>6</SUB>Mn precipitates surrounded by α-Al matrix. An addition of Mm into the Al<SUB>94</SUB>Mn<SUB>6</SUB> alloy generates icosahedral quasicrystalline phase (IQC) with an extinction of hexagonal and Al<SUB>6</SUB>Mn phases, and the fraction of IQC increases continuously with an increase in Mm content. Compressive yield strength (<I>σ</I><SUB>cys</SUB>) and ultimate compressive strength (<I>σ</I><SUB>ucs</SUB>) of the AlMnMm alloys are improved with Mm content up to 4%, whereas elongation is steeply deteriorated by the Mm addition. The Al<SUB>90</SUB>Mn<SUB>6</SUB>Mm<SUB>4</SUB> alloy exhibits the highest 570 and 783MPa of <I>σ</I><SUB>cys</SUB> and <I>σ</I><SUB>ucs</SUB>, respectively, both of which are comparable to those of Al<SUB>90</SUB>Mn<SUB>6</SUB>Ce<SUB>4</SUB> alloy.</P>

Influence of Microstructural Change on Damping Capacity of Mg-X%Li Alloys

Jun, Joong Hwan,Seong, Ki Duk,Kim, Jeong Min,Kim, Ki Tae,Jung, Woon Jae Scientific.Net 2007 Materials Science Forum Vol. No.

<P>The Effects of Li content and annealing treatment on microstructure and damping capacity for Mg-X%Li alloys have been investigated, based on experimental results from X-ray diffractometry (XRD), optical microscopy (OM), hardness tests and vibration damping tests in a flexural mode. The Mg-X%Li alloys containing Li of 3%, 8% and 13% consist of α (HCP) single phase, (α + β (BCC)) dual phases and β single phase, respectively. In as-rolled state, the damping capacity for Mg-Li alloys shows a similar level regardless of Li content. The annealing treatments at 200oC and 400οC give rise to an enhancement of damping capacity only for the Mg-3%Li and Mg-8%Li alloys containing α phase, and at the same annealing temperature, the Mg-3%Li alloy with fully α structure exhibits higher damping capacity. This result indicates that the damping capacity of Mg-Li alloys depends principally on α phase, and that the annealing treatment is necessary to improve its damping capacity.</P>

Influences of Si and Co Addition on Microstructure and Damping Capacity of Fe-Mn Alloy

Jun, Joong Hwan,Lee, Young Kook,Kim, Jeong Min,Kim, Ki Tae,Jung, Woon Jae Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.319 No.-

<P>Microstructures and damping properties have been investigated in Fe-23%Mn-(0~2)%Si and Fe-23%Mn-(0~2)%Co alloys, based on experimental results from metallography, X-ray diffractometry and vibration test in a flexural mode. The amount and number density of ε martensite are increased with an increase in Co content, resulting in the improvement of damping capacity. For the same ε martensite content, the higher the Co content, the greater the damping capacity. On the contrary, an addition of Si affects to decrease the amount and number density of ε martensite, giving rise to a decay of damping capacity. The decreased ε martensite content by the addition of Si would be attributed to an increase in critical driving force for the γ→ε martensitic transformation by solution hardening effect.</P>

Microstructure and Tensile Creep Behavior of Mg-Nd-RE-Ca Casting Alloys

Jun, Joong Hwan,Park, Bong Koo,Kim, Jeong Min,Kim, Ki Tae,Jung, Woon Jae Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.345 No.-

<P>Influences of Ca addition on microstructures and mechanical properties at room and elevated temperatures have been investigated for Mg-1.5%Nd-1.0%RE-0.5%Zn-(0~1.0)%Ca casting alloys, on basis of experimental results from X-ray diffractometry (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), tensile and creep tests. Microstructures of the alloys are characterized by dendritic α-(Mg) grains surrounded by Mg12Nd-Zn-(Ca) eutectic network phase. The average size of α grains decreases gradually with an increase in Ca content. At room temperature, yield strength (YS) is enhanced with increasing Ca content with a decrease in ultimate tensile strength (UTS) and elongation to fracture, whereas the Ca addition leads to greater YS and UTS at 175oC. The tensile creep strain and secondary creep rate, measured at 150 and 200oC under 100MPa for 100hrs, become lower with the increase in Ca content. The obtained tensile properties at elevated temperature demonstrate that the addition of Ca plays a role in improving high temperature mechanical properties including creep resistance for the Mg-Nd-RE-Zn-(Ca) alloys. In view of microstructural evolution, this would be attributed to the refined primary α grains and higher thermal stability of the Mg12Nd-Zn-Ca eutectic strengthening phase.</P>

Enhanced Mechanical Properties of A206 Aluminum Casting Alloy by Addition of Rare Earth Elements

Jun, Joong Hwan,Kim, Jeong Min,Seong, Ki Duk,Kim, Ki Tae,Jung, Woon Jae Trans Tech Publications, Ltd. 2005 Materials science forum Vol.475 No.-

<P>Changes in tensile properties of A206 Al-Cu-Mg casting alloys containing trace amount of rare earth(RE) elements up to 0.2% were investigated and discussed in relation to the microstructural evolution. The A206 alloy with 0.1%RE shows higher values of ultimate tensile strength(UTS) and yield strength(YS) than A206 alloy at room and elevated temperatures up to 300oC, whereas no remarkable change is found in elongation with respect to RE addition. In view of X-ray diffractometry(XRD) and transmission electron microscopy(TEM), the improvement of tensile strength in the A206 alloy with 0.1%RE would be caused by higher number density of Al2Cu(q¢) strengthening precipitates.</P>