職務特性이 職務滿足에 미치는 影響力에 관한 硏究 : 生産職 從業員을 中心으로

梁龍柱 청주대학교 기업경영학연구소 1987 經營學論集 Vol.9 No.-

Double Probe 측정법에 의한 RFI 플라즈마 특성에 관한 연구

전용주,박원주 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.1

Electron temperature and electron density were measured in RFICP(Radio-Frequency Inductively Coupled Plasma) by using double probe method. Measurements were conducted in argon discharge for pressures from 30mTorr to 60mTorr and input RF powers from 50W to 200W and gas flowrates from 3sccm to 12sccm. Radial distributions of electron temperature and electron density were measured for discharges for the same aspect ratio (R/L=1). Electron temperature was found to depend on pressures and gas flowrates, but just weakly on powers. Electron temperature was almost constant while input RF power was increased, and decreased with increasing pressures, and that electron temperature had a tendency to get lower at low gas flowrates when argon gas flowrate was increased, but it is considered that there is just slight changes in tendency, if any, with increasing gas flowrates. Electron density depended on all of pressures, input RF powers and gas flowrates. Electron density increased with increasing input RF powers, and was kept constant for the gas flowrates, and that it increased with increasing gas flowrates. Radial distribution of the electron temperature was seen to gradually increase from plasma center toward plasma environs. Radial distribution of the electron density was peaked at the plasma center. These results make it easier for us to understand the generation and stay-on mechanism of RFICP.

탄소환원에 의한 Zircon으로 부터 고순도 Zirconia 제조에 관한 연구

유용주,이재식 울산대학교 1991 공학연구논문집 Vol.22 No.2

감압하에서 지르콘사를 탄소환원하므로 지르코니아의 고순도화에 대한 연구를 하였다. 지르콘과 탄소의 혼합물을 1 Torr의 진공로 중에서 가열함으로써, 지르콘 중의 SiO₂는 SiO(g)로 제거되었으며, 이 SiO(g)는 로의 낮은 온도 구역에서 미세한 백색 무정형 분말인 SiO(s)로 응축되었다. 생성된 지르코니아에는 미량의 탄소, ZrO 그리고 ZrC등이 존재하였으나, 공기중에서 산화 반응후에는 지르코니아 단일상으로 되었다. 단일상 지르코니아는 1500℃, C/SiO₂몰비 1.0 일때 SiO₂의 함유량이 가장 작았다. 이러한 공정의 반응 생성물은 XRD, SEM-EDX 및 습식방법 등에 의해서 분석하였으며, 지르코니아 분말의 순도는 99.8%이었고 결정구조는 단사정이었다. A production technics of high-purity ZrO₂ powder from zircon (ZrO₂· SiO₂) were investigated by carbothermic reduction under reduced pressure. The mixture of zircon and carbon was heated in the range of 1200℃ to 1500℃ in vaccum furnace under the condition of 1 Torr. The reaction product for the process was examined by XRD, SEM-EDX, and chemical analysis. By this techniques, the SiO₂ in zircon was removed as SiO(g). The generation of SiO(g) from a Zircon/Carbon mixture at high temperature to was greatly enchanced by reduction of pressure compared to atmospheric. Zirconia powder contaminated with a small amount of carbon, ZrO, and ZrC was obtained before oxidation reaction. Single-phase ZrO₂ was obtained after oxidation reaction of Zirconia powder when the the C/SiO₂ mole ration in the Zircon/Carbon mixture was 0.5∼2.0. The SiO₂content in ZrO₂ powder was minimized at a C/SiO₂ ratio of about 1.0. The monoclinic phase zirconia powder with a high purity of 99.8% and fine grain size was obtained. The SiO(g) generated in the process condensed as a fine white amorphous powder in the low-temperature zone of the vaccum furnace, having an ultrafine grain size.

SCM 435 구조용강의 플라즈마 질화에 관한 연구

유용주,김인수,이재식 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 연구는 SCM 435 구조용강을 450∼650℃의 온도범위에서 NH₃가스유량을 0.5∼2.1 l/min로 변화시키고, 20∼110분 동안 플라즈마 질화처리하여 강 표면에 생성된 경화층의 두께와 경도 및 조직을 조사하였다. 반응온도 550℃, NH₃1.65 l/min.에서 110분 동안 질화 하였을 경우 생성된 질화층의 두께는 260㎛으로써, 화합물층은 16㎛ 이며, 확산층은 224㎛로 이것이 최대의 질화층이었다. 한편, 반응온도 600℃, NH₃1.65 l/min. 가스유량에서 50분간 반응하였을때 24㎛의 최대 화합물층을 얻을 수 있었다. 또한 화합물층은 450℃와 500℃에서는 r'- Fe₄N-α-Fe로, 550℃에서는 r'-Fe₄N+ε- Fe₃N으로, 600℃이상에서는 r-Fe₄N+α-Fe로 구성되어있는 혼합상이었다. 550℃,NH₃1.65 l/min. 에서 80분 동안 질화처리하였을때 생성된 질화층의 최대 표면경도는 Hv 988이었다. The plasma nitriding of SCM 435 structural steel has been studied at the temperature between 450℃ and 650℃ with gas flow rate of NH₃ 0.5 to 2.1 l/min. for 20 to 110 minutes. The phases of compound layer formed below 500℃ and above 600℃ was mixture of r'-Fe₄N and ε- Fe₂₄N phases, while the phases formed 550 was r' - FeN and - Fe N phases. The hardness of nitrided layer formed at 550℃ with gas flow rate of NH₃ 1.65 l/min. for 80minutes was Hv 988. The thickness of nitrided layer formed at 550℃ with gas flow rate of NH 1.65 l/min. for 110minutes was 260㎛. The nitriede layer was composed of 16㎛ compound layer and 244㎛ diffusion layer.

EMF 측정법에 의한 Cu-Co-O System의 열역학적 연구

유용주,이재식 울산대학교 1990 연구논문집 Vol.21 No.1

고체 전해질인 (ZrO₂+ CaO)를 사용하여 구성된 다음과 같은 galvanic cell들을 이용한 EMF를 측정함으로써, Cu₂O, CuO, CoO의 Cu₂CoO₃생성에 대한 자유에너지 값을 얻었으며, Cell(1) Ni, NiO/ZrO₂(+CaO)/Cu, Cu₂O Cell(2) Ni, NiO/ZrO₂(+CaO)/CuO, Cu₂O Cell(3) Co, CoO/ZrO₂(+CaO)/Ni, NiO Cell(4) Co, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(5) Cu, Cu₂O, CoO/ZrO₂(+CaO)/Cu,Cu₂O Cell(6) Cu₂O, CoO, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O Cell(7) CuO, Cu₂O, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O 그 결과들은 아래와 같다. △ G˚??, Cu₂O=-40548+17.494 T cal/mole(970-1258K) △ G˚??, CuO=-36062+20.084 T cal/mole(1162-1332K) △ G˚??, CoO=-56680+17.394 T cal/mole(1126-1326K) 그리고 2 CuO+CoO=Cu₂CoO₃반응에 대한 △G˚=-1618+0.9838 T cal/mole(1162-1332K)이며, 계산된 Cu₂CoO₃의 생성에 대한 자유에너지 값은 △G˚, Cu₂CoO₃=-130423+58.542T cal/mole이다. 그리고 Cu₂CoO₃에 대한 Cu₂O와 CuO의 용해도는 매우 작았다. The equilibrium oxygen pressures of the binary and threephase regions [Cu-O], [Co-O], [Cu, Cu₂O, CoO], [Cu₂O, CoO, Cu₂CoO₃] and [CuO, Cu₂O, Cu₂CoO₃]were measured as a function of temperature by the solid oxide electrolyte (ZrO₂+ CaO) electromotive force method. The galvanic cells used were as follow: Cell(1) Ni, NiO/ZrO₂(+CaO)/Cu, Cu₂O Cell(2) Ni, NiO/ZrO₂(+CaO)/CuO, Cu₂O Cell(3) Co, CoO/ZrO₂(+CaO)/Ni, NiO Cell(4) Co, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(5) Cu, Cu₂O, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(6) Cu₂O, CoO, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O Cell(7) CuO, Cu₂O, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O The results were expressed by the following equations: G˚??, Cu₂O=-40548+17.494 T cal/mole(970-1258K) G˚??, CuO=-36062+20.084 T cal/mole(1162-1332K) G˚??, CoO=-56680+17.394 T cal/mole(1126-1326K) The measured Gibbs energy of the reaction 2 CuO+CoO=Cu₂CoO₃was found to be -1618+0.9838 T cal/mole(1162-1332K). The evaluated Gibbs energy of formation of △G˚, Cu₂CoO was found to be -130423+58.542T cal/mole. The solubility of Cu₂CoO₃in Cu₂O or CuO is very small.

플라즈마 질화법에 의한 SKD 11 공구강의 표면 경화에 관한 연구

유용주,이재식,공경준 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 연구는 온도범위 450 - 650℃, NH₃ 가스유량 0.5 - 2.1 l/min., 처리시간 20 - 110분의 조건에서 SKD 11 냉간 금형용 공구강을 플라즈마 질화처리하여 강 표면에 생성된 경화층(화합물층 및 확산층)의 조성 및 두께와 각각의 경도값을 조사하여 질화의 최적조건을 찾고자 하였다. 반응온도 550℃, NH₃2.1 l/min., 반응시간 110분일 경우 14㎛의 최대 화합물층을 얻었으며, 반응온도 550℃, NH₃1.65 l/min.로 110분간 반응시켰을 때 생성된 확산층은 210㎛였으며, 최대 질화층은 220㎛이었다. 또한, 플라즈마 질화처리한 SKD 11 냉간 금형용 공구강 표면과 화합물층을 XRD로 분석한 결과 450℃와 500℃에서는 r' - Fe₄N + α - Fe로, 550℃에서는 r' - Fe₄N - ε -Fe₂₃N, 그리고 600℃ 이상에서는 r' - Fe₄N + α + Fe로 구성되어 있는 혼합상이었다. 550℃, NH₃1.65l/min., 80분간 질화처리 하였을 때 생성된 질화층의 최대표면경도는 Hv 1100이었다. The plasma nitriding of SKD 11 tool steel has been studied at the temperature between 450℃ and 650℃ with gas flow rate of NH₃ 0.5 to 2.1 l/min. for 20 to 110 minutes. The phases of compound layer formed below 500℃ and above 600℃ was mixtures of r'-Fe₄N and α- Fe phases, while the phases formed at 550℃ was r'-Fe₄N and ε-Fe₂₄N phases. The thichness of compound layer formed at 550℃ with gas flow of NH₃2.1 l/min. for 110 minutes was 14㎛. The thickness fo nitrided layer formed at 550℃ with gas flow rate of NH₃1.65 l/min. for 110 minutes was 220㎛. The nitrided layer was composed of 10㎛ compound layer and 210㎛ diffusion layer. The hardness of nitrided layer formed at 550℃ with gas flow rate of NH₃ 1.65 l/min. for 80minutes was Hv 1100.

초음파영상을 이용한 정상 교근의 평가

황형주,김규태,최용석,황의환 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.2

Purpose : To assess the internal echo intensity and morphological variability of masseter muscles on ultrasonography and to establish diagnostic criterion of estimation. Materials and Methods : Participants consisted of 50 young adults (male 25, female 25) without pathologic conditions and with full natural dentitions. Sonographic examinations were done with real time ultrasound equipment as Logiq 500 (GE Medical Systems, Seoul, Korea) at 3 parts according to lines paralleling with ala-tragus line as reference line. The thickness and area of masseter muscles according to reference line in cross-sectional images were measured at rest and at maximum contraction. The visibility and width of the internal echogenic intensity of the masseter muscles were also assessed and the muscle appearance was classified into 4 types. Data were statistically analyzed by paired t-test and x²-test. Results : 1. When comparing the thickness and area of masseter muscles concerning with gender, there was few significant difference between right and left sides, however, there were significant differences between males and females except for the greatest thickness of left side. 2. The changes of the greatest thickness and the area between rest and maximum contraction showed that the part of the least thickness manifested more increase at maximum contraction. 3. Each part the manifestations of the internal echogenic intensity of the masseter muscles were different depending on the locations. But there was no statistically significance. Conclusion : Changes of muscles thickness with contraction and internal echogenic intensity with locations showed great disparity within the masseter muscles, which will be diagnostic criteria for pathophysiologic and anatomic changes of masseter muscles.

마이크로 펄스 플라즈마 질화법에 의한 선박엔진용 부품의 표면경화에 관한 연구

이재식,유용주 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 연구는 마이크로 펄스 플라즈마 질화처리한 FCD60, S53C, SCM440강재를 고주파 유도경화 열처리한 동일 강재와의 비교분석을 통해 강 표면에 생성된 경화층의 두께와 경도 및 조직을 조사하고 마모시험을 행하였다. Hv550의 유효경도를 갖는 경화깊이는 마이크로 펄스 플라즈마 질화의 경우 FCD60, S53C, SCM440에서 각각 30㎛,25㎛,25㎛이었고, 고주파 유도경화 열처리는 각각 1.4mm이었다. 경화층의 XRD분석결과 마이크로 펄스 플라즈마 질화의 경우 FCD60과 S53C는 주로 r'- Fe₄N, SCM440은 r' - Fe₄N과 ε- Fe₃N의 혼합상이 생성되었으며, 고주파 유더경화 열처리된 경화층은 α- Fe로 모재와 같았다. 또한, 마모시험결과 상온에서는 고주파 유도경화 열처리에 의해 생성된 경화층이 내마모성이 좋으나, 고온(150℃)과 윤활상태에서는 마이크로 펄스 플라즈마 질화처리하에 의하여 생성된 질화층의 내마모성이 우수하였다. The case hardening of FCD60, S53C and SCM440 by micro-pulse plasma nitriding and high frequency induction heat treatment was invesigated. The effective case depth (of which hardeness is over Hv550) of FCD60, S53C and SCM440 nitrided by micro-;ulse plasma method was 30, 25 and 25㎛, respectively. XRE analysis of nitrided layer, showed that mixture of r' - Fe₄N and ε- Fe₃N phases formed on SCM440, r' -Fe₄N single phase formed on S53C and FCD60. In case of hihh frequency induction heat treatment, hardened layer was α - Fe single phase. The hardened hayer formed by high frequency induction heat treatment was more resistant to wear than nitrided layer at room temperature, however nitrided layer by micro-pulse plasma nitriding was more resistant to wear than induction hardened layer at high temperature and lubricated condition.

동전해정제시 음극분극전위에 미치는 첨가제의 영향에 관한 연구

오기식,유용주,김영홍 울산대학교 1985 연구논문집 Vol.16 No.2

전해첨가제를 동전해액(황산동-황산)에 각각 단독으로 또는 복합적으로 첨가하여 음극분극전위를 측정함으로써 다음과 같은 결론을 얻었다. 1) 첨가량이 많아짐에 따라 아교와 글리신은 음극분극전위를 현저히 높이며, 아비톤-A는 약간 증가시키고, 티오요소는 소량 첨가할 경우 감소시키나 첨가량이 많아지면 상당히 상승시킨다. 그리고 Cl?은 음극분극전위에 영향을 거의 미치지 않는다. 2) 아교를 주 첨가제로하고 티오요소 및 아비톤-A를 첨가했을 때 티오요소와 아비톤-A는 분극전위에 거의 영향을 미치지 못하고 주로 아교가 영향을 미친다. 3) 아교 5mg/l, 티오요소 3mg/1, Cl? 20mg/l를 가한 전해액을 이용한 일반적인 전해정제로 2.5A/dm²의 고전류밀도에서 평활하고 치밀한 전착면을 얻을 수 있었으며, 불순물의 제거가 가능하고 부동태현상이 발생 하지 않았다. Cathodic polarization potentials during the ectrorefining of copper have been measured under various conditions of addition agents in the copper electrolyte (CuSO₄-H₂SO₄). The results obtained are as follows. 1) The cathode polarization potential is affected by the kind of addition agents and the amount of addition to the electrolyte. Glue and glycine show remarkable increasing effects on the polarization potential, Aviton-A has a little effect. However, thiourea causes the polarization potential to increase considerably at high concentration, but showing a decreasing effect at low concentration. Chlorine has little effect on the polarization potential. 2) In the case of using the electrolyte containing glue with Aviton-A and glue with thiourea as additives, thiourea and Aviton-A have little effect on the polarization potential, while glue shows remarkable effect. 3) The electrorefining was carried out successfully using the electrolyte added glue 5mg/l, thiourea 3mg/l, and chlorine 20,g/l, with the current thiourea 3mg/l, and chlorine 20mg/l, with the current density of 2.5A/dm² for 68hrs at the pilot plant. The surface of deposit copper was smooth and its thickness was uniform, showing the purity of 99.99( copper.

편측성 완전 구순구개열 환자의 포괄적 치료

이정근,황병남,최은주,김용빈 대한악안면성형재건외과학회 2000 Maxillofacial Plastic Reconstructive Surgery Vol.22 No.4

Cleft lip and palate is one of the congenital anomalies which need comprehensive and multidisciplinary treatment plan because 1) oral cavity is an important organ with masticatory function as a start of digestive tract, 2) anatomic symmetry and balance is esthetically important in midfacial area, and 3) it is also important to prevent psycho-social problems by adequate restoration of normal facial appearance. There are many different protocols in the treatment of cleft lip and palate, but our department has adopted and modified the Z□rich protocol, as published in the Journal of Korean Cleft Lip and Palate Association in 1998. The first challenge is feeding. Type of feeding aid ranges from simple obturators to active orthopedic appliances. In our department we use passive-type plate made up of soft and hard acrylic resin which permits normal maxillary growth. We use Millard's method to restore normal appearance and function of unilateral complete cleft lip. In consideration of both maxillary growth and phonetic problems, we first close soft palate at 18 months of age and delay the hard palate palatoplasty until 4 to 5 years of age. When soft palate is closed, posterior third of the hard palate is intentionally not denuded to allow normal maxillary growth. In hard palate palatoplasty the mucoperiosteum of affected site is not mobilized to permit residual growth of the maxilla. We have treated a patient with unilateral complete cleft lip and palate by Ajou protocol, which is a kind of modified Z□rich protocol. It is as follows: Infantile orthopedics with passive-type plate such as Hotz plate, cheiloplasty with Millard's rotation-advancement flap, and two stage palatoplasty. It is followed by orthodontic treatment and secondary osteoplasty to augment cleft alveolus, orthognathic surgery, and finally rehabilitation with conventional prosthodontic treatment or implant installation. The result was good up to now, but we are later to investigate the final result with longitudinal follow-up study according to master plan by Ajou protocol.