Effect of Ultrasonic Melt Treatment on Solidification Microstructure of Al–5Ti–1B Alloy Containing Numerous Inoculant Particles

Soo‑Bae Kim,Jae‑Gil Jung,Young‑Hee Cho,Su‑Hyeon Kim,Kwangjun Euh,Jung‑Moo Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The effect of ultrasonic melt treatment (UST) on the solidification microstructure of an Al–5Ti–1B alloy containing highvolumefractions of Al3Tiand TiB2particles is investigated for various UST times with different melt holding times. Theas-cast Al–5Ti–1B alloy is composed of TiB2and polygonal Al3Tiparticles (present prior to UST), plate-like Al3Tiparticles,and Al grains (formed during UST and/or solidification). The UST causes a size reduction and homogeneous distributionof the TiB2-agglomerated region containing many submicron-sized TiB2particles pushed to the grain boundaries. The USTslightly decreases the size and improves the distribution of polygonal Al3Tiparticles enriched in the TiB2-agglomeratedregion. Unlike the TiB2and polygonal Al3Tiparticles, which exhibit a minor refining effect, the plate-like Al3Tiparticlesshow a significant refinement with UST application. The UST has a significant effect on the size distribution of Al grains byinducing the formation of medium-sized grains at the expense of small and large grains; however, it only has a slight effecton grain refinement. The degree of microstructure modification increases with increasing UST time but decreases with meltholding time after UST. The mechanisms for the refinement and dispersion of the TiB2and Al3Tiparticles and Al grains arediscussed considering fragmentation, nucleation, and growth behaviors induced by the UST and subsequent solidification.

관동맥 우회로술 중 경식도 심초음파도로 관찰한 도부타민 투여후와 우회로술후의 좌심실 국소벽운동

김희열,김종진,윤호중,유기동,박지원,이길환,노태호,채장성,김재형,홍순조,최규보 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.8

생쥐의 강제수영시 부동자세시간과 통각예민도간의 상관관계

김길중,박제민,김명정 大韓神經精神醫學會 1991 신경정신의학 Vol.30 No.4

The purpose of the study is to test by an animal experiment the hypothesis that pain insensitivity in depression is a trait marker rather than a state marker. 39 mice were studied for pain sensitivity by means of tail flick test before and after 6 minutes of forced swimming and for total duration of immobility during the last 4 minutes of forced swimming. The correlation coefficients were calculated among the basal pain sensitivity, the change of pain sensitivity after forced swimming and duration of immobility during the forced swimming. The results are as follows. 1) A significant positive correlation was proved between the degree of pain insensitivity and duration of immobility during forced swimming. 2) The forced swimming induced a significant pain insensitivity and a significant negative correlation was shown between duration of immobility and the change of pain sensitivity after forced swimming. From these results, the author suggests that pain insensitivity in depression may be a trait marker rather than a state marker depending on the state of depression itself.

모래다짐말뚝 개량폭에 따른 보강효과에 관한 연구

김시운,정길수,박병수,유남재 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A

In this research, centrifuge model experiments and numerical approach of finite element method to analyze experimental results were performed to investigate the behavior of improved ground with sand compaction piles. One of typical clay minerals, kaolinite powder, were prepared for soft ground in model tests. Jumunjin standard sand was used to sand compaction pile installed in the soft soil. In order to investigate the characteristics of mechanical behavior of sand compaction piles with low replacement ratios, centrifuge model experiments with the replacement ratio of 40%, changing the width of improved area with respect to testing results the width of surcharge loads, were carried out to obtain of bearing capacity, characteristics of load-settlement, vertical stresses acting on the sand pile and the soft soil failure mechanism in improved ground.

방위특징 탐지 단순신경세포들의 배열순서에 관한 연구

김길중,김정국,서광명,서용수 동서대학교부설연구소 1998 연구소 논문집 Vol.3 No.-

Cells in avisual cortex line in columns which are perpendicular to the cortical surface and the cortical cells in a column prefer to respond to an orientation of each line segments of an sesory image. orientation preference of each cortical column is highly correlated to those of nearbycolumns and varies smoothly anlong the surface of the cortex. To elucidate the mechanism of this columnar organization, we propose a simple model consisting of orientation selective neruons(OSNs) with local facilitation and lateral inhibition. it is playsible that modifiable connections play an important role in forming and refining the organization togher with the sensory experience. Thus the feed-forward connections between OSNs and LGN cells are modifiable. The interactions between OSNs in the same layer take place by way of feedback pathways and are excitatory and inhibitory. The behavior of the model is described by a STM equations of Growwberg and critical parameter of negative one dimensional ??G function, σ would give variety to the differences in detected orientations.

제품보호용 포장재 개발

김정필,강재현,박대연,유성구,서길수 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.1

The environment to which a packaged-product is exposed, during handling and transportation, very often includes temporary storage. In the interest of conserving warehouse cube, packaged-products are stacked upon one another to a height which far exceeds that possible in a railcar, truck-trailer, aircraft or other conveyance. the hight to which the height to which a packaged-product may be stacked will vary depending upon the warehouse ceiling height-seldom over twenty feet. This procedure for expirimental covers testing of packaged-products weighing under 100 pounds when prepared for shipment. The BASIC requirements of this procedure consist of vibration and drop tests-which must be performed in that sequence.

황국균과 백국균의 대두 코지제조중 키토산의 효과

정순택,문길만,조건식,강성국,김설희 木浦大學校 工業技術硏究所 1998 工業技術硏究誌 Vol.8 No.-

The effect of chitosan in soybean koji preparation and characteristics of chitosan-koji were investigated. Aspergillus oryzae KCTC 6096 and Aspergillus kawachii KCCM 11458 was used for koji preparation. a-Amylase activity of soybean koji prepared with 0.25% 10cp chitosan was excellent relative to 30 cp chitosan and 1.6 times higher than non-added soybean koji. Acid and neutral protease activities of soybean koji prepared with 0.25%, 10 cp chitosan were showed simillary higher value than non-chitosna added koji. The period of koji preperation was reduced 30% by adding chitosan.

Delay Line을 이용한 1차 미분 임펄스 발생기 설계

김은정,임재현,김길겸,김학선 한밭대학교 정보통신전문대학원 2004 정보통신전문대학원 논문집 Vol.2 No.1

본 논문에서는 UWB (Ultra-WideBand)시스템에 사용되는 짧은 폭의 임펄스 발생기를 설계하였다. SRD와 두개의 단락된 전송 선로를 이용 하였다. 단락된 전송 선로는 시간 지연과 위상의 반전을 효과적으로 제공 한다. RC 미분기 대신에 단락된 전송 선로(Delay Line)을 이용하여 1차 미분 임펄스를 발생시켰다. 시뮬레이션을 통해 700psec의 펄스폭과 600mV(p.p)의 진폭, 펄스 모양의 좋은 대칭성을 확인하였고 또한, 펄스 주변의 떨림 현상이 거의 발생하지 않았다. In this paper, we have designed impulse generator of short pulse width for UWB(Ultra-Wide band) system using SRD and two short-circuited stubs. The short-circuited stub provides good time delay and reverse of phase. The first derivative impulse was generated by using short-circuited stub(Delay Line) instead of RC differentiator. A first derivative impulse of 700 psec pulse duration, 600mV(p.p) pulse amplitued, and good symmetry has been demonstrated though simulation. Also, there are extremely small amount of ringing around the first derivative impulse.

Bacterial Synthesis of a Flavonoid Deoxyaminosugar Conjugate in <i>Escherichia coli</i> Expressing a Glycosyltransferase of <i>Arabidopsis thaliana</i>

Kim ,, Bong‐,Gyu,Jung ,, Na Ri,Joe, Eun Ji,Hur, Hor‐,Gil,Lim, Yoongho,Chong, Youhoon,Ahn, Joong‐,Hoon WILEY‐VCH Verlag 2010 Chembiochem Vol.11 No.17

<P><B>Just add sugar</B>: An unnatural flavonoid‐deoxyaminosugar conjugate was biologically synthesized in <I>Escherichia coli</I> by engineering an <I>E. coli</I> nucleotide–sugar pathway and expressing a glycosyltrandfease specific for UDP‐arabinose derivatives. </P>

발열이 있는 호중구 감소증 환자에서의 위험도 예측인자

정중식,권운용,김규석,임용수,이중의,서길준,윤여규 대한응급의학회 2000 대한응급의학회지 Vol.11 No.3

Background: Most febrile neutropenic patients are treated in an aggressive manner. However, identification of low-risk patients may enable clinicians to administer risk-based treatment. The object of this study is to certify the factors associated with increased risk at the time of visiting the emergency department. Methods: This is a retrospective study. We reviewed the medical records of 101 febrile neutropenic patients who had visited the emergency department of Seoul National University Hospital from January 1998 to August 1999. We assumed 22 risk prediction factors that could be assessed at admission to the emergency department and 5 factors that could be assessed during treatment course. To find independent risk-prediction factors, we analyzed these factors respectively by using multiple regression analysis. Results: Tachycardia(aOR=136.5), altered mentality(aOR=28.8), decreased renal function(aOR=20.1), and significant comorbidity(aOR=17,2) are the independent factors associated with higher mortality. Altered mentality(aOR=31.6) and decreased renal function(CCr < 75㎖/min, aOR=5.4) are those associated with a higher incidence of septic shock. Independent factors associated with persistent(more than 3 days) fever are the early(within 10 days) onset of fever after last chemotherapy(aOR=8.8) and the existence of new pulmonary infiltrates on a simple chest X-ray(aOR=4.3). Conclusion: The stability of vital signs, the change of mentality, the renal function, the existence of significant comorbidity, the existence of new pulmonary infiltrates, and the rate of neutropenia are clinically useful risk-prediction factors in febrile neutropenia at the time of visiting the emergency department.