간세포암의 고주파 열치료 후 천자침 경로를 통한 전이 1례

조영완,박석주,진한영,김준영,이재익,강명주,박정하,윤정희,박성재,지삼룡,이연재,이상혁,설상영 인제대학교 2006 仁濟醫學 Vol.27 No.-

Radiofrequency ablation(RFA), as a form of minimally invasive therapy for hepatocellular carcinoma, has become an important treatment modality. Because of limitation of surgery, RFA has become standard therapy for hepatocellular carcinoma in some situations. But there are some complications of RFA such as bleeding, infection, hematoma, adjacent organ thermal damage including intestinal perforation, needle track seeding, and so on. There are few reports in the literature that systematically evaluate the incidence of needle tract seeding and its associated risk factors. And only 2 cases of needle tract seeding of hepatocellular carcinoma after RFA were reported in Korea. We report a case of needle tract seeding of hepatocellular carcinoma after RFA.

타타늄의 열처리 조건에 따른 동전위 양극분극특성 및 표면 미세구조 변화

주동현,이용렬,정영화,양홍서,박상원,이도재,송호준,박영준 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.2

The corrosion resistance of metallic implants is essential for successful implant osseointegration. Moreover, the implant surface should have appropriate surface roughness for the attachment of the osteoblast and collagen fibrils. When titanium is exposed to air a thermodynamically very stable oxide film is formed at once. This oxide is very thin and yet it protects the metal from corrosion instantaneously. However, the oxide would not be ideal, and it would be supposed that the state of oxide film would be various by the different conditions when it is formed. The objective of this study was to evaluate the electrochemical properties and surface microstructural changes of titanium after passivation treatment or exposure to high heat (in vacuum or in air). ASTM grade 2 commercially pure titanium (Ti) disks of 10㎜ diameter were wet ground and polished with 240 and 600 grit SiC, and then ultrasonically cleaned with distilled water and ethanol. Cleansed as-received samples (As-R group) were passivated with 30% nitric acid solution at 50℃ for 15 minutes to make the Pas group. The Std-V samples were made by treating the Ti disks in vacuum quartz tube (10^-8 Torr) at 530℃ for 40 min for stress relieving, followed by annealing at 700℃ for 90 min, and then slow cooling to room temperature. The Std-A samples undergo identical procedure as the Std-V group except that it is done in air. For 530℃-V samples, Ti disks were heated at 530℃ for 40 minutes and slow cooled to room temperature. The 1000℃-V samples were produced by heating Std-V specimens again at 1000℃ for 2 hr, followed by cooling to room temperature. 530℃-A and 1000℃-A samples were also prepared. Potentiodynamic anodic polarization measurement, SEM, AFM and XRD analysis were performed to evaluate the effects of the various treatments. The difference in the mean values of E_corr between groups showed statistically significant difference (P<0.05), but that of I_corr did not show significance (P>0.05). When Ti surface was passivated there was a shift of corrosion potential (E_corr) in the noble direction and a lower corrosion current density (I_corr) value. Std-A samples showed most noble E_corr value among the tested groups. 530℃-V samples showed more noble E-corr than other tested groups except Std-A group. 1000℃-V samples showed more noble E-corr than those of Std-V sample. In the case of Std-, 530℃- and 1000℃-groups, -A sub-groups showed better corrosion resistant characteristics than -V sub-groups in regard to E-corr and I_corr values. In the SEM observations, the surfaces of the As-R samples showed only scratch line on smooth surface. In Pas samples, thick oxide layer covered the surface under high magnification observation. 530℃-A samples were covered by oxide granules, and Std-A samples had 25~50 nm-thick acicular oxides. The 1000℃-A samples were covered by coarse oxide crystals with a granule diameter of 0.1~0.6 μm having a gross appearance of milky white color, which was identified by XRD as a rutile. On the other hand, 1000℃-V samples showed an Widmansta¨tten structrue of which the orientation of the lattice is formed along crystallographic planes of the parent crystals. On the AFM observation, 530℃-A samples showed RMS roughness of 79.38 nm which is 5 times rougher than those of the As-R samples. Std-A sample had a roughness of 330.47 nm which is about 20-times rougher than that of the As-R sample. 1000℃-A samples were covered by coarse granular oxides and the roughness were about 0.56 μm. Vacuum sub-group samples showed a more smooth surface than air sub-group samples, and the oxide film was more dense. Due to variability of the surface treatment and heat treatment conditions, the process of the oxide formation seems to be affected thereby making the corrosion properties and surface micro-morphology different. However, more various electrochemical analysis together with surface analysis, and an investigation for the effects of those on the osteoblast cell adhesion and calcium phosphate apposition are needed for the improvement of the osseointegration rates of the titanium implants.

구간분할 제어를 이용한 형상기억합금 와이어의 히스테리시스 특성에 관한 연구

정상화,김주환 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

Shape memory alloy(SMA) is one of artificial actuators used in the anthropomorphic robot hand. It generates displacement by input of heat or electric current on the entire SMA wire. SMA has a prominent strain hysteresis and its phase transition is dependent on temperature, stress and the direction of motion. Conventional control methods of SMA wire use the analogue, approach such as Galerkin method, Preishach method, slide mode, neural fuzzy, etc. The position control of SMA which uses the analogue approach is difficult. In this paper, the hysteresis characteristics of SMA wire using segment control is studied. SMA wire is controled by the digital approach. Thermo-electric module(TEM) which can heat and cold the same surface using the h-bridge circuit is used for segmenting a SMA wire and hysteresis of segmented SMA wire is measured.

구간 분할 제어를 이용한 형상기억합금 와이어의 온도제어에 관한 연구

정상화,김주환,김태호,서호진,박진완 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

The key technology of robot is the design of the actuator. Particularly breakthroughs of power-to-weight ratio or energy-density III actuator technology have significant impacts upon the design and the control of robotic systems. To realize the anthropomorphic motion, artificial muscles such as shape memory alloy(SMA) and electro active polymer(EAP) are used. These actuators have the higher energy density than the electromechanical actuators such as the electric motor. The EAP has the property of good elasticity, but it is difficult to get the required power. The SMA has the good power density and simple structure, but the control scheme of the actuator is difficult. In this paper, temperature control of SMA wire using segment control is studied. The SMA wire is segmented by thermo-electric module(TEM). To supply constant currents in TEMs, MOSFET is used. Hysteresis in one segment of SMA wire is evaluated. The force and displacement of SMA wire are measured according to the number of segment. The program to control the temperature of TEM is developed by using LabVIEW software.

리튬이 도핑된 막을 이용한 실리콘-실리콘 접합

정지원,주병권,최우범,정성재,이남양,최두진,오명환 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

Silicon-to-silicon anodic bonding was accomplished using lithium doped interlayer. Lithium doped interlayers were deposited on silicon substrates by electron beam evaporation, which has a fast deposition rate compared with sputtering method. Silicon-to-silicon bonding occurs in the range of temperatures from 250℃ to 300℃ with the applied voltages from 70V_(DC) to 100V_(DC). The bonding strength obtained from tensile test was about 5MPa under the condition of 80V_(DC) in 300℃. The surface morphology of lithium doped interlayer was studied with the atomic force microscopy (AFM). Finally, secondary ion mass spectroscopy (SIMS) analysis was carried out in order to investigate the role of the lithium ions in bonding mechanism.

초경합금 소재 LCU_CL 코어의 초정밀 연삭 특성에 관한 연구

정상화,차경래,김현욱,이봉주 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

As the various manufacturing technology of optical glass is developed, the aspherical lenses are applied to many fields. However, It is still very difficult to manufacture glass lens because of the high cost and the short life of core. In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. In the glass mold lens, it has merits of high productivity and reproductivity since lens is manufactured by the only forming with high precision mold. The fabricating conditions for glass mold lens are glass surface that does not cause fusion, viscosity of 108-1013 poise for the 0.2㎛ accuracy, and viscoelasticity for the roughness less than 100 angstrom. In this thesis, ultra-precision grinding characteristics of tungsten carbide for forming the aspherical glass lens core were studied and the result of it is applied to manufacture the tungsten carbide-base core of the glass lens used to the laser scanning unit and the camera phone.

Effect of Mechanical Alloying on the Microstructural Evolution of Al60Cr30Si10 Alloys Processed by Spark Plasma Sintering

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

In this study, Al, Cr and Si fine powders were alloyed by planetary ball milling to investigate their microstructural evolution,following their mechanical alloying behavior. The formation of Al(Cr) supersaturated solid solution by the Cr grainsembedded in Al-matrix, which contributed substitutional structure is discussed in relation to their structural evolution inaccordance with the distortion of a crystal lattice. The compacts of Al–Cr–Si alloys were prepared by rapid sintering withina short time by dense consolidation above the density of 99.9% as the formation of intermetallics, except in the case of thedistribution of single-phases induced by the Al-melting. The formation behavior of intermetallics was dominated by dependenceon the structures of the milled-powder and subsequent sintering temperature. To estimate the consolidated behaviorsof compacts, various approaches derived from TEM and XRD analysis were taken to obtain microstructural evidences ofthe inter-diffusion, following the presence of thermally stable intermetallics.

Rapid Consolidation of WC‑ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4was fabricated by spark plasma sintering at 1400 ℃ ata constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried outfor 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. Itwas observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents,and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact wasfound to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical propertiesof the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to thepresence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zirconfrom a transgranular to a ductile component (fcc) where the crack tips could be absorbed.

Camphorsulfonic acid로 doping된 전도성 polyaniline의 free standing film 제조 및 용매의 선택에 따른 특성변화

정상국,오응주,서정선 명지대학교 자연과학연구소 1994 자연과학논문집 Vol.11 No.-

aniline을 0℃, 1M HCI 용액내애서 (NH4)2S208을 산화제로 사용하여 산화중합시킴에 의하여 polyanline(emeraldine salt)을 합성하였고, 이르 NH4OH로 deprotonation시켜 절연성의 emeraldine base(EB)를 합성하였다. EB를 o-chlorophenol, m-cresol, chloroform등의 용매내이서 camphorsulfonic acid(HCSA)로 DOPING 하여 높은 전도성의 polyaniline을 제조하였다.o-chlorophenol, m-cresol내에서 가공된 용액은 440nm에서의 흡수피크와 1000nm에서 시작하여 2600nm까지 점차 흡수세기가 증가하는 free carrier tail 을 보였고, 이로부터 가공된 free standing film은 ~220S/cm의 높은 전기전도도와 부분적으로 결정성인 X-선 회절패턴을 나타내었다.반면에 chloroform내에서 가공된 용액은 ~800nm에서의 localized polaron에 기인하는 흡수피크를 나타내었고, 이로부터 가공된 free standing film은 ~10??S/cm의 전기전도도와 비정형의 X-선 회절패턴을 나타내었다. 이와같이 같은 양성자산으로 doping된 polyaniline이 사공시 사용된 용매에 따른 전기도도,UV/Vis,-NIR spectra및 결정구조를 갖는 현상을 용매에 따른 고분자사슬의 conformational change로 설명하였다. Insulating polyaniline (emeraldine base :EB) was synthesized by oxidative polymerization of aniline at~0℃ in IM HCI using (NH4)2S2O8 as a oxidnt and then deprotonation in 0.1M NH4OH and was converted to highly conducing form by protonic acid doping with camphorsulfonic acid (HCSA) in various ewak or non polar solvents. Free standing films of camphorsulfonic acid doped polyamilines cast from these solvents exhibited conductivities of 10?~200S/cm which depends on the kinds ofn silvents.(e.g.~200S/cm in m-cresol, 0.1S/cm in chloroform, 0.5S/cm in formic acid etc.).Thin films spun from m-cresol slution onto quartz substrates exhibited an electronic abosorption at~440nm and a intense free carrier tail comencing at ~1000nm and steadyily increasing in intensity to ~2600nm which is consistent with delocalized electrons in polarn band supporting metalic character. On the other hand those spun from chloroform showed localized polaron absorption at 440nm and ~800nm. Also free standing films cast from m-cresol showed partly crystalline structure whereas those cast from chlorofrm showed amorphous X-ray diffraction pattern. These phenomena were explained by the changes in polymer chain conformation in different solvents.

Telomere의 기능 손실에 의한 Telomerase 결핍 세포의 성장 억제에 대한 연구

주연진,박정은,전경미,김창민,김상훈,박원봉,이기호 대한암예방학회 2002 Journal of cancer prevention Vol.7 No.3