• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.74-74
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• 2009

Titanium nitride has been used as hardmask for semiconductor process, capacitor of MIM type and diffusion barrier of DRAM, due to it's low resistivity, thermodynamic stability and diffusion coefficient. Characteristics of the TiN film are high intensity and chemical stability. The TiN film also has compatibility with high-k material. This study is an experimental test for better condition of TiN film etching process. The etch rate of TiN film was investigated about etching in $BCl_3/Ar/O_2$ plasma using the inductively coupled plasma (ICP) etching system. The base condition were 4 sccm $BCl_3$ /16 sccm Ar mixed gas and 500 W the RF power, -50 V the DC bias voltage, 10 mTorr the chamber pressure and $40\;^{\circ}C$ the substrate temperature. We added $O_2$ gas to give affect etch rate because $O_2$ reacts with photoresist easily. We had changed $O_2$ gas flow rate from 2 sccm to 8 sccm, the RF power from 500 W to 800 W, the DC bias voltage from -50 V to -200 V, the chamber pressure from 5 mTorr to 20 mTorr and the substrate temperature from $20\;^{\circ}C$ to $80\;^{\circ}C$.

• 한국지반공학회논문집
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• 제21권4호
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• pp.115-122
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• 2005

본 연구에서는 토사사면의 안전율을 산정하고 최소임계단면을 탐색하기 위하여 개별요소법과 유전자 알고리즘으로 조합된 새로운 해석방법이 제안되었다. 안전율 산정시, 한계평형법에 근거한 통상적인 사면안정 해석법들은 전체적인 힘평형을 만족하지 못하기 때문에 절편간에 작용하는 힘의 경사와 위치에 대한 가정이 불가피하다. 개별요소법에 근거하여 개발된 사면안정해석법은 힘과 변위간의 적합조건을 만족할 수 있다. 또한 제안된 해석기법에서는 최소임계 단면을 탐색하기 위하여 실수형 유전자 알고리즘이 적용되었다. 이 방법은 지역해에 쉽게 수렴하는 간편한 최적화기 법보다 안정적으로 전역해를 탐색할 수 있다 제안된 해석기법의 적용성을 검토하기 위하여 예제해석이 수행되었다.

• KCI Concrete Journal
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• 제14권1호
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• pp.36-42
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• 2002

Flexural behaviors of the two typical precast beam sections (inverted tee and rectangular) for buildings were investigated and compared. The height of web in the inverted tee beam was generally less than half of beam depth to be adapted to that of the nib in the ends of double-tee where the total building height limited considerably. The inverted-tee beams were designed for a parking live load - 500kgf/$m^2$ and a market - 1,200kgf/$m^2$ from the currently used typical shape of a domestic building site in Korea. The area and bottom dimension of rectangular beams were the same as those of inverted tee beams. These woo beams were also reinforced with a similar strength. following results were obtained from the studies above; 1) the rectangular beam is simpler in production, transportation, and erection, and more economic than the inverted tee beam in the construction test for these two beams with a same dimension and a similar strength, 2) all of the beams considered in the tests were generally failed in values close to those of the strength requirements in ACI Provisions. The ratios of test result to calculated value are averaged to 1.04. One rectangular and one inverted tee beams failed in a value only 2-3％ larger than the estimated volue of the Strength Design Methool the results of the Strain Compatibility Method wire slightly more accurate than those of the Strength Design Method, 4) the maximum deflections of all of the beams under the full service loads were less than those of the allowable limit in ACI Code Provisions. The rectangular beams experienced more deflection then inverted tee in the same loading condition and failed with more deflection, and 5) the rectangular and inverted tee beams showed good performances under the condition of service and ultimate loads. However, one inverted tee beams with fm span developed an initial flexural crackings under 88％ of the full service load even though they designed to satisfy the ACI tensile stress limit provisions.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.839-850
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• 2002

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components'characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.

• 콘크리트학회논문집
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• 제28권3호
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• pp.279-288
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• 2016

이 연구에서는 철근콘크리트(reinforced concrete, RC) 기둥의 휨 거동을 비교적 간단한 방법으로 평가하기 위해서 모멘트-곡률 관계를 단순화하였다. RC 기둥에서 주철근 배근을 이상화하고 힘의 평형조건 및 변형률 적합조건에 기반하여 초기 휨 균열 발생, 인장철근 항복 도달, 최대 내력 및 최대 내력 도달 후 최대 내력의 80% 시점에서의 내력과 중립축 깊이를 산정하였다. 기둥의 최대 내력 이후의 콘크리트 압축연단 변형률은 Kim et al의 구속된 콘크리트 응력-변형률 관계를 이용하여 산정하였다. 단순화된 모멘트-곡률 관계로부터 환산된 기둥의 횡하중-횡변위 관계는 다양한 변수하에서 수행한 기둥 실험결과와 잘 일치하였다. 고려된 각 단계에서의 모멘트와 중립축 깊이는 주철근 지수, 횡보강근 체적지수 및 축력 지수의 함수로 모델링하였다. 결국, 기둥의 곡률 연성은 콘크리트 압축강도 및 주철근과 횡보강근의 양과 함께 작용 축하중비에 중요한 영향을 받았다.

• 한국기계가공학회지
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• 제13권1호
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• pp.1-7
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• 2014

An impeller is difficult to machine due to the complex, overlapping and twisted shapes that form the blades of an impeller. Therefore, most CAM software companies have developed a CAM module for manufacturing an impeller in addition to their CAM software. However, it is not easy for inexperienced users to machine impellers. The purpose of this paper is to outline the development of an automatic CAM module for the manufacturing of an impeller (E-ICAM) which is based on visual basic language and which uses a CATIA graphical environment in order to simplify the machining of impellers. The automatic CAM module generates a tool path and proposes the recommended cutting condition according to the stock and tool material. In addition, it includes a post-processor for five-axis control machining. Therefore, a user can easily machine impellers using this automation module. There are two types of impellers: the closed and open types. The closed-type impeller consists of the body and cover parts. To combine these two parts, it is necessary to create tap holes on the shroud of the body. Therefore, in the study, a drilling CAM program for a closed-type impeller is developed and manufactured by creating NC data from the developed drilling program. After manufacturing the test specimen, its compatibility was verified.

• Archives of Plastic Surgery
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• 제36권4호
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• pp.397-405
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• 2009

Purpose: Soft tissue defect of anterior chest wall is caused by trauma, infection, tumors and irradiation. To reconstruct damaged anterior chest wall does require to consider the patient's body condition, the cause, the location, the depth and the size of deletion, the circulation of surrounding tissue and minimization of functional and cosmetic disability. In this report, we suggest the algorithm of configuration for reconstruction methods. Methods: A retrospective study of 20 patients who underwent anterior chest wall reconstruction with pedicled musculocutaneous flap and fasciocutaneous flap was conducted. We collected the information of the patient's body condition, the cause, the size, the depth and the location of deletion, implemented flap and complication. We observed and evaluated flap compatibility, functional and cosmetic results. Patients completed survey about the extent to their satisfaction. Result: Follow up period after surgery was from 6 to 26 months, survival of flap were confirmed in all of patients' case. Two cases of local necrosis, one case of wound disruption were reported, but all these were cured by the debridement and primary closure. One hematoma and one seroma formation were observed in donor site. Longer surgery time, more bleeding amount and more transfusion volume were reported in the group of musculocutenous flap. Conclusion: Long term follow up result showed the successful reconstruction in all patients without recurrence and with minimal donor site morbidity. In addition, the patients' satisfaction for cosmetic and functional results were scaled relatively higher. This confirmed the importance of reconstruction algorithm for the chest wall reconstruction.

• Journal of Pharmaceutical Investigation
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• 제6권1호
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• pp.26-32
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• 1976

Dicalcium phosphate dihydrate (DCPD) is the most widely-used dentifrice abrasive in non-therapeutic tooth-paste requiring, low abrasive level, high stability and excellent compatibility with other formulation ingredients. One of the difficulties encountered in the use of this material in tooth-paste is that unless storage of the product is maintained at a relative low temperature there is a distinct tendency to lose water of crystallization. Another difficulty which has been encountered is that there is a tendency for the product to become lumpy. Various means have been proposed for increasing the stability and overcoming the lumping tendency, most of which means comprise the addition of stabilizing agent. But there is not any report about the relationships between the mechanism of dehydration, physical properties, structure and manufacturing condition. In this experiment, DCPD were manufactured by methods of Moss' patent, its two varied and J.P.VIII, these were studied by means of stability test, IR spectra, and DTA. According to the manufacturing conditions, DCPD has different physical properties and structures, i. e., monoclinic system of low drying temperature, triclinic system of high drying temperature. Dehydration of DCPD may be supposed one step debydration at about $100^{\circ}$ and it finaly converts to ${\gamma}-pyrophosphate$ at about $465^{\circ}$ and if the drying temperature is high it becomes DCP anhydrous. DCPD made by Moss' patent is thought of the best polishing agent of tooth-paste.

• Structural Engineering and Mechanics
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• 제87권3호
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• pp.255-272
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• 2023

Spatial cable systems can provide more transverse stiffness and torsional stiffness without sacrificing the vertical bearing capacity compared with conventional vertical cable systems, which is quite lucrative for long-span earth-anchored suspension bridges' development. Higher economy highlights the importance of refined form-finding analysis. Meanwhile, the internal connection between the lateral and vertical sags has not yet been specified. Given this, an analytic algorithm of form-finding for the earth-anchored suspension bridge with spatial cables is proposed in this paper. Through the geometric compatibility condition and mechanical equilibrium condition, the expressions for cable segment, the recurrence relationship between catenary parameters and control equations of spatial cable are established. Additionally, the nonlinear general reduced gradient method is introduced into fast and high-precision numerical analysis. Furthermore, the analytic expression of the lateral and vertical sags is deduced and discussed. This is very significant for the space design above the bridge deck and the optimization of the sag-to-span ratio in the preliminary design stage of the bridge. Finally, the proposed method is verified with the aid of two examples, one being an operational self-anchored suspension bridge (with spatial cables and a 260 m main span), and the other being an earth-anchored suspension bridge under design (with spatial cables and a 500 m main span). The necessity of an iterative calculation for hanger tensions on earth-anchored suspension bridges is confirmed. It is further concluded that the main cable and their connected hangers are in very close inclined planes.

• 한국환경생태학회지
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• 제35권3호
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• pp.237-255
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• 2021

제비동자꽃(Lychnis wilfordii (Regel) Maxim.)은 주로 고위도의 이탄습지에 분포하는 전문종이다. 우리나라에서는 2개 지역에 고립되어 분포한다. 본 연구에서는 생육지 특성, 생장특성 및 자가화합성 그리고 안정적인 개체군을 유지하고 있는 용늪습지보호지역에서 개체군의 지속에 관여하는 내적 동태를 평가하였다. 분포지의 식생환경은 용늪습지보호지역과 평창군 대관령면 분포지 사이에 뚜렷한 차이가 있었다. 화분매개충의 방문에 의해 종자의 생산이 촉진되기는 하지만 자가화합성을 함께 소유하였다. 토양의 유기물함량이 높은 조건에서 다수의 겨울눈을 생성하였고, 줄기 수, 열매 수가 최대에 달하였다. 그렇지만 유기물함량이 낮은 조건에서도 생장하고 개화하여 종자를 생산하였다. 용늪습지보호지역에서 제비동자꽃은 고층습원에는 분포하지 않았고 뚝사초가 형성하는 사초기둥이 발달한 저층습원에 분포하였다. 제비동자꽃은 이 공간에서도 사초기둥의 상단부에 주로 분포하였다. 따라서 뚝사초가 형성하는 사초기둥의 생성, 성장 및 소멸은 이 공간에 분포하는 식물의 정착, 성장, 소멸과 밀접한 연관이 있는 것으로 판단되었다. 현재 용늪습지보호지역은 제비동자꽃이 분포하는 사초기둥이 발달한 공간이 넓게 분포하고 있고 소멸과 재정착의 과정이 잘 이루어지는 것으로 평가되었다. 그러므로 현재와 같은 생태적 과정이 잘 유지된다면 용늪습지보호지역의 제비동자꽃 개체군은 오랜 기간에 걸쳐 지속 가능할 것으로 예상되었다.