모조 근관의 크기와 충전 방법이 orthograde MTA apical plug의 미세누출에 미치는 영향

남득림,박정길,허복,김현철 大韓齒科保存學會 2009 Restorative Dentistry & Endodontics Vol.34 No.3

The purpose of this study was to compare the dye leakage of MTA (mineral trioxide aggregate) apical plug produced by two orthograde placement techniques (hand condensation technique and ultrasonically assisted hand condensation technique). To simulate straight canal, 60 transparent acrylic blocks with straight canal were fabricated. These transparent acrylic blocks were divided into 2 groups (Group C: hand condensation technique (HC) and Group U; ultrasonically assisted hand condensation technique(UAHC)) of 30 blocks with each MTA application method. Each group was divided into 2 subgroups (n = 15) with different canal size of #70 (subgroup C70 and subgroup U70) and #120 (subgroup C120 and subgroup U120). After apical plug was created, a wet paper point was placed over the MTA plug and specimen was kept in a humid condition at room temperature to allow MTA to set. After 24 hours, remaining canal space was backfilled using ObturaⅡ. All specimens were transferred to floral form socked by 0.2% rhodamine B solution and stored in 100% humidity at room temperature. After 48 hours, resin block specimens were washed and scanned using a scanner. The maximum length of microleakage was measured from the scanned images of four surfaces of each resin block using Photoshop 6.0. Statistical analysis was performed with Mann-Whitney U test. Group U of UAHC had significantly lower leakage than Group C of HC in #70-size canal (subgroup U70) (p<0.05). 이 연구의 목적은 서로 다른 두 개의 근관 크기(#70, #120)를 가진 레진 모형에 MTA (mineral trioxide aggregate)를 서로 다른 두 가지 방법 (수기구 충전(HC), 초음파 보조 수기구 충전(UAHC))으로 정방위 충전하고 MTA apical plug의 미세누출을 평가하는 것이다. 직선형 근관 형태를 가지며, #70과 #120의 치근단 크기를 갖는 레진 모형을 각각 30개씩 준비하였다. 이 시편들을 MTA의 적용 방법에 따라 각 군을 2개의 아군으로 다음과 같이 분류하였다 (n=15); C70: HC + 치근단 크기 #70, C120: HC + 치근단 크기 #120, U70: UAHC + 치근단 크기 #70, U120: UAHC + 치근단크기 #120. MTA충전을 완료한 후에, 24시간 동안 실온에서 100% 습도를 유지하여 경화시켰다. 근관의 상부는 열연화 충전 시스템(Obtura Ⅱ)을 이용하여 충전하였다. 48시간 동안 100% 습도를 유지하여 실온에서 0.2% rhodamine B 용액을 이용해 미세누출 실험을 하였다. 이 연구결과 #70의 치근단 크기를 갖는 그룹 사이에서 UAHC가 HC에 비해 미세누출이 적은 것으로 나타났다(p<0.05). 이 연구 조건하에서는 초음파 진동을 동반한 정방위 MTA apical plug 형성 방법이, 특히 좁은 근관에서 더 효율적 인 것으로 사료된다.

Preparation and Characterization of Metallocene-catalyzed Isotactic Polypropylene and,or Syndiotactic Polypropylene Single Crystals; Preliminary Studies

( Deuk Kil Park ),( Jin Woo Park ),( Chang Sik Ha ) 한국 접착 및 계면학회 2005 접착 및 계면 Vol.6 No.2

Preparation and Characterization of Metallocene-catalyzed Isotactic Polypropylene and/or Syndiotactic Polypropylene Single Crystals; Preliminary Studies

Park, Deuk-Kil,Park, Jin-Woo,Kim, Il,Ha, Chang-Sik The Society of Adhesion and Interface 2005 접착 및 계면 Vol.6 No.2

Single crystals of metallocene-catalyzed isotactic polypropylene (iPP) and/or syndiotactic PP (sPP) were prepared and preliminarily characterized. The crystallization was performed utilizing 0.1 % by weight concentrations of each PP in o-xylene in the range of temperature of $40{\sim}90^{\circ}C$. Following the XRD patterns, samples were ${\alpha}$-iPP and antichiral Cell III of sPP. The XRD pattern of iPP shows three ${\alpha}$-form peaks due to the (110), (040), (130) planes at $2{\theta}=14.2^{\circ}$, $17^{\circ}$, $18.8^{\circ}$, respectively. The XRD pattern of sPP is characterized by the presence of the (020) reflection at $16^{\circ}$. The melting point ($123^{\circ}C$ and $148^{\circ}C$, respectively) of the metallocene catalyzed iPP and sPP were generally lower than that of conventional PP ($160{\sim}170^{\circ}C$) due to the misinsertion of the monomer. When metallocene-catalyzed iPP samples were crystallized isothermally from solution grown at a lower temperature, lozenge shape single crystals were observed by transmission electron microscopy (TEM).

통각유발물질로 인한 Group Ia Muscular Afferents의 Impulse 발사

박창득,남숙현,홍승길 고려대학교 의과대학 1983 고려대 의대 잡지 Vol.20 No.1

In anaesthetized cats the effects of chemically activated muscle spindle upon group Ia muscular afferents were studied. The afferent activity was extracellularly recorded from small filaments of dorsal roots. 1) KCI and bradykinin activated muscle spindle and increased the imulse discharges through group Ia muscular afferents. 2) Muscle spindle of gastrocnemius soleus could be diveded into three groups, which responded only to KCI, only to bradykinin and to both of them. 3) The impulse discharges of group Ia muscle afferents induced by KCI and bradykinin was similar to the impulse discharge of group Ⅲ and group Ⅳ nerve fiber by KCI and bradykinin. 4) It was suggested that muscle spindle is a polymodal receptor due to the fact of responding to not only mechanical stimuli but also chemical substances.

Experimental research on 2 stage GM-type pulse tube refrigerator for cryopump

Park, Seong-Je,Ko, Jun-Seok,Hong, Yong-Ju,Kim, Hyo-Bong,Yeom, Han-Kil,Koh, Deuk-Yong The Korean Society of Superconductivity and Cryoge 2010 한국초전도저온공학회논문지 Vol.12 No.2

The experimental results of the 2 stage Gifford-McMahon(GM) type pulse tube refrigerator (PTR) or cryopump are presented in this paper. The objectives of his study are to develop design technology of the integral type 2 stage PTR which rotary valve is directly connected to he hot end of the regenerator and acquire its improved performance. Design of the 2 stage PTR is conducted by FZKPTR(Forschungs Zentrum Karlsruhe Pulse Tube Refrigerator) program for the design of pulse tube refrigerators. The fabricated PTR has U-type configuration and incorporates orifice valve, double-inlet valve and reservoir as phase control mechanism. Rotary valve is used to make pulsating pressure and is directly connected to inlet of $1^{st}$ stage regenerator. From experiments, cooling performance map and pressure waveform at each point were measured for different operating frequencies. Experimental results show the best cooling performance with 2 Hz operation in spite of small pressure amplitude. The lowest temperatures of the 2 stage PTR were 16.9 K at the second stage and 58.0 K at the first stage. The cooling capacities achieved were 14.4 W at 79 K, the first stage and 3.6 W at 29 K, the second stage.

An Experimental Investigation of the G-M type Pulse Tube Refrigerator

Park, Seong-Je,Koh, Deuk-Yong,Yeom, Han-Kil,Hong, Yong-Ju,Kim, Hyo-Bong The Korea Institute of Applied Superconductivity a 2004 한국초전도저온공학회논문지 Vol.6 No.2

The experimental results of the G-M (Gifford-McMahon) type pulse tube refrigerators are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The objectives of this study are to develop the design technology of the G-M type pulse tube refrigerator and acquire its application methods for replacing G-M cryocooler. As a preliminary test, the refrigeration performances of the basic, orifice, and double inlet pulse tube refrigerators were investigated. The lowest temperature obtained in the one-stage pulse tube refrigerator was 34.4K and the refrigeration capacity at the optimum operation condition was 23W at 80K. And the lowest temperature of the second stage cold head in the two-stage pulse tube refrigerators was 18.3K and the refrigeration capacities at optimum condition were 0.45W at 20K and 20W at 80K, respectively. Finally, the lowest temperature obtained in the three-stage pulse tube refrigerator was 29.8K and the refrigeration capacity at the optimum operation condition was 1.3W for 40K and 5W for 70K.

운동피로가 골격근내의 젖산량 변동에 미치는 영향

박창득,홍승길 고려대학교 의과대학 1980 고려대 의대 잡지 Vol.17 No.1

Changes in content of muscle lactate recovering from single bouts of exhaustive exercise were studied in rat. Performing maximal exercise by means of a forced running in a motor drive treadmill at a speed 40m/min for 30 minutes, the muscle samples were obtained at rest and different time intervals in the recovery periods. The lactate content in muscle tissue were measured by Barker and Summersons method. Control value (mean±S.E.) for muscle lactate was 15.11±0.87㎎%. At immediately after, 6hr., 12hr., and 24hr. after exercise the lactate content were 51.12±2.83㎎%, 45.46±4.67㎎, 15.55±0.26㎎% and 6.98±0.28㎎ respectively.

서귀포 연안해역의 기초생산에 영향을 미치는 해양환경

박길순,정상철,노홍길,전득산 한국수산학회 1983 한국수산과학회지 Vol.16 No.4

족관절 외과의단독골절에서 골절 안정성의 판정

박현수,이우천,라종득,한영길,임장운 대한골절학회 1998 대한골절학회지 Vol.11 No.4

Recent advances in the understanding of the biomechanics of the ankle have given rise to the clinical uncertainty about the indications for the operative treament of isolated fractures of the lateral malleolus. If deltoid ligament injury is associated, it may be unstable and operation may be indicated. This study was done to determine if we are able to assess the stability of the isolated lateral malleolus fracture based on the fracture patterns seen on radiographs and clinical findings. 37 patients with malleolar fracture of the ankle were treated at Hanil General Hospital by open reduction and internal fixation from Dec. 1996 to Jan. l998. Lauge-Hansen classification was tried in all cases to determine if it could be applied. Stress test under anesthesia on 10 isolated lateral malleolar fracture patients with clinical findings of injury on the deltoid ligament area, whose medial clear space were normal or widened less than 2 mm on initial film. Exploration of the deltoid ligament was performed in 6 of above 10 patients There were 21 supination-external rotation type injuries, 2 supination-adduction injuries, 1 pronation-abduction injury and 13 fractures could not be clearly categorized into specific group. In 6 among 13 unclear cases, there were short oblique fracture line indicating pronation injury, but direction of thc fracture line could not be clearly determined. In 4 cases, direction of the fracture line indicated pronation injury, but the length of the fracture line was too long. In 3 cases, both the direction and length of the fracture line was indeterminate. The stress test on 10 isolated lateral malleolar fractures with clinical findings of deltoid injury revealed less than 2 mm widening in 7 cases, more than 2 mm widening in 3 cases. In 3 cases with less than 2 mm widening, tearing of anterior third of superficial deltoid was confirmed by exploration. In 3 cases with more than 3 mm widening, partial rupture of the deep deltoid was observed in 2 cases and anterior third of superficial deltoid was torn in 1 case. We suggest that we cannot clearly assess the stability of isolated lateral malleolar fracture either by fracture patterns or clinical findings, so stress test can be considered in determining the stability.

Thermal Quench in HTS Double Pancake Race Track Coil

Jae-deuk Lee,Young-kil Kwon,Seung-kyu Baik,Eon-yong Lee,Young-chun Kim,Tae-sun Moon,Heui-ju Park,Woon-sik Kwon,Jung-pyo Hong,Minwon Park,Inkeun Yu,Young-sik Jo Institute of Electrical and Electronics Engineers 2007 IEEE transactions on applied superconductivity Vol.17 No.2

<P>In large scale applications, such as SMES, motors and generators, High Temperature Superconducting (HTS) magnets are constructed with many stacks of the double-pancake coils connected in series. In spite of its higher thermal stability, HTS magnet can experience a severe quench, which can resulted from a very small portion. From HTS magnet design point of view, it is very important to predict the possibility of occurrence quench in the designed magnet to provide a suitable quench protection device. In this paper a highly instrumented HTS race track double-pancake coil was prepared to examine the quench development characteristics. It is wound using the Bi-2223 tape. Many voltage taps, cryogenic thermocouples and heater were installed in the winding. Conduction cooling method is adapted for the convenience of temperature. Quench development in the coil was measured under different operating current. The experimental details and results are presented in this paper.</P>