폴리머 링 Add/Drop 필터와 지연 도파로로 구성된 가변 광 신호 지연기

문현승 광운대학교 대학원 2015 국내석사

대용량 고속 통신 시스템에 대한 요구가 급증함에 따라 높은 품질의 광대역 광통신 네트워크의 중요성이 점증하고 있다. 이에 따라 광 신호를 전기신호(Optical-to-Electrical)로 변환하여 라우팅 된 패킷들이 광신호(Electrical-to-Optical)로 변환될 필요 없이 광 데이터 패킷의 교환이 가능한 광 패킷 스위칭 기술을 이용한 전광(All-Optical) 네트워크에 대한 관심이 증가하고 있다. 전광 네트워크를 위해서는 광 버퍼, 광 동기화, 광 스위치 등의 기능을 수행하는 모듈이 필요한데, 이를 위해서는 가변적인 광 신호를 시간 지연 시킬 수 있는 소자 설계 및 제작 기술이 필요하다. 본 논문에서는 광 신호 지연 소자로서 폴리머 링 add/drop 필터와 지연 도파로로 구성된 가변 광 신호 지연기를 설계 및 제작하였다. 코어는 폴리머 물질인 ZPU-12로 가로와 세로의 길이가 각각 1.8㎛의 정사각형 형태이며, 이러한 코어를 감싸고 있는 클래딩은 폴리머 물질인 LFR로서 매립형 도파 구조이다. 이때 코어의 굴절률은 1.48이고 클래딩의 굴절률은 1.37로서, 약 7.4%의 높은 굴절률 차를 가진다. 이러한 큰 굴절률 차로 높은 광 구속력을 얻을 수 있다. 그리고 add/drop 필터 각각의 상부에 증착되어 있는 전극에 전류를 인가하여 발생되는 열을 이용하여 링 공진기 주변의 굴절률을 조절함으로써 공진 파장을 변화 시킬 수 있다. 측정결과 두 번째 add/drop 필터를 공진시켜 한 개의 딜레이 라인을 통과한 경우 약 110 ps, 세 번째 add/drop 필터를 공진 시켜 두 개의 딜레이 라인을 통과한 경우에는 225㎰, 네 번째 add/drop 필터를 공진 시켜 세 개의 딜레이 라인을 통과한 경우에는 약 330㎰의 시간 지연을 확인 할수 있었다. 즉, 통과하는 딜레이 라인의 개수에 비례하여 시간 지연이 늘어나는 것을 확인 할 수 있었고 이를 통하여 광 코드 분할 다중 접속 (OCDMA : Optical Code Division Multiple Access) 부호화기/역부호화기 (Encoder/Decoder)로의 활용 가능성을 확인 할 수 있었다. According to increasing demand for high-speed communication of large capacity, researches on all-optical communication network become very active. For the realization of the all-optical network, optical buffer, optical synchronization, optical switching modules are essential. Especially, a variable optical-signal delay device is required for the implementation of optical buffers. In this paper, a variable optical signal delay device composed of polymer ring add/drop filters and delay waveguides is designed and fabricated. The core is ZPU-12 polymer material whose width and height are 1.8㎛, respectively. The cladding is LFR polymer material. The core and cladding refractive index are 1.48 and 1.375, respectively, which corresponds to the relative index difference of 7.4%. Due to the high index contrast between core and cladding, optical waveguide has strong confinement of the light. Four pairs of electrodes are evaporated above the add/drop filters to provide heating currents. When current is injected, the refractive index decreases due to temperature increase, and then the resonance wavelength of ring resonators moves toward shorter wavelength. The time delay is measured to be 110㎰ when the second add/drop filter is in resonance and 225㎰ when the third add/drop filter is in resonance and 330㎰ when the fourth add/drop filter is in resonance. In the measurement, we can identify variable time delay in proportion to the number of delay lines. With these experiments, the fabricated device can be applied to OCDMA encoder/decoder.

주거 만족도 분석을 통한 도심재생 활성화에 관한 연구

문현승 전주대학교 일반대학원 2018 국내박사

In the past, the meaning of 'residence' had been recognized with the narrow meaning of preventing the intrusions from the outside as well as independent and private spaces including the simple meaning of dwelling, entering into the recent times. However, the residence currently has been recognized with an expanded concept that considers the benefits of the individuals including the relationship with the surroundings, the infrastructure, and the welfare. As the changes of the residence taking place according to the satisfaction of residential areas, the lifestyles, and the urban development, it is time to study based on qualitative approach such as satisfaction degree to the residences which are felt by the residents. And, as the dwelling quality is an important scale that determine the lives of the human beings, we need to research continuously based on the quality and the value of the dwelling. Recently, to have growth pole effects in some local innovation cities based on national balanced development policy, the new towns form the bridgeheads for the urban growths for the future by planning. In addition, the deteriorated areas of old and original city centers have been also improved within their region and the actual levels of satisfactions with the residences have been much improved. On the other hand, due to an innovative city construction Jeonju region has been recently forming to be the largest new city. And, it has been expanding from the Haga District and the Jeonju New Town basically had built over 10 years ago. As a result, we need to escalate the regeneration projects regarding the old and original city centers by taking a look at the differences between the natives who moved after the Jeonju New town had been created and the residents in the old and original city centers. At same time we need to provide the materials needed for the accompanied growth within the downtown of Jeonju by comparing with the levels of the satisfactions with the dwellings of the residents in the new city, Therefore, we propose and give some advices regarding the developments of the other innovation cities and the old and original city centers. For this study, using statistical techniques based on questionnaire surveys, we explored dwelling satisfaction level after classifying the fundamental factors of residence into five types of characteristics: location, education, culture, social relation, and economy in different regions of the city. In order to identify the findings, seven analysis tools were used: Frequency analysis, significancy (by Cronbach’s coefficiency), factor analysis, t-test, ANOVA, IPA, and structural equation analysis. In particular, we explored the factors of the level of satisfaction with the dwelling of both old city center and new town (innovation city) in Jeonju City. By a path coefficient significance test, we explored the intention to reside for a long time and the intention to recommend, as for a factor that gives the influence on the level of satisfaction with regard to residing in Jeonju City. As a result, first of all in the old city center, it appeared as being the special characteristics of the location with the positive (+) influence at 0.387. Secondly, in new town of Jeonju City, the intention to reside for a long time, and the intention to recommend, as for a factor that gives the influence on them, it appeared as being the special characteristics of the location with the positive (+) influence at 0.312. And, as for a factor that gives the influence on the intention to recommend, it had special, social, and cultural characteristics. And it appeared as having the negative (-) influence at -0.203. It is judged that the intention to recommend was lower because, in the case of a new city, the accessibility to the public facilities and the cultural facilities falls low. Regarding a difference between the old city center and the new city in relation to the points of difference of the residential environments, the level of satisfaction of the residents in the new cities regarding the organization of the residential estates, the protection of the private life, the apartment brands, the leisurely activities, etc. was high. In the case of the old and original city centers, because the protection of the private life has been weak, including the problem of the narrowness of the deteriorated apartments, the problem of the noise in the staircase-type ones and the corridor-type ones and others of the like, the difference that is felt at the dwelling has been taking place. The difference between the old city center and the new city has a very close relationship with the economy. And, we identified that special, locational characteristics of the dwelling are directly related with the level of the satisfaction. However, to the extent that the redevelopment through a reorganization of the city cannot be done and there are the relationships between the neighbors, forming the economic foundation and replacing the physical elements of the residence are probably the most important elements in the invigoration of the old city center. Also, regarding the viewpoint of the urban regeneration of the old city center, the urban organization considering the special, local characteristics like the Hanok Village (Korean traditional houses) and the formation of the economic foundation are needed as old city center have become slums or deteriorate areas because the residential relocations to the new cities have kept on taking place according to the increases of the economic activities and the employment creations in the new cities. In conclusion, it is judged that it will be improved in level of satisfaction with the residence in the old city centers. Finally, it will be desirable to proceed with the urban vitalizations of the old city center through the decentralization, and not the crowding, of the public organizations and the representative corporations of Jeonju City. The residential problems of the old city center and the new city had become internal ones of the city as whole, and not only Jeonju City, though they have been growing. In order to identify the significant difference of spatial changes in both regions, more improved analysis techniques and more findings are required. Based on these analysis results, it is expected that this study will contribute to escalating of dwelling satisfaction levels for the future.

폐리튬이온배터리로부터 코발트, 니켈 및 구리의 회수를 위한 습식공정의 개발

문현승 목포대학교 대학원 2022 국내석사

리튬이온배터리는 높은 에너지 및 전력 밀도와 같은 우수한 성능으로 인해 휴대폰, 노트북과 같은 휴대용 장치의 발전과 전기자동차시장이 확대됨에 따라 사용량이 급격히 증가하고 있으며 많은 양의 폐배터리가 생성될 것이다. 또한 폐리튬이온배터리에는 많은 유가금속들이 함유되어 있어 이를 회수하는 것에 대해 많은 관심을 끌고 있다. 최근의 폐리튬이온배터리의 처리방법으로 건식제련과 습식제련의 조합하여 건식법으로 고온에서 리튬과 알루미늄은 산화슬래그로 회수 하며, 코발트, 니켈 및 구리는 용융환원되어 금속합금상으로 얻어진다. 이에 따라 금속합금상의 코발트, 니켈, 구리의 목적금속을 습식제련법으로 분리하기 위해 침출, 용매추출 및 침전법으로 목적금속의 회수를 조사했다. 본 논문에서는 얻어진 금속합금상의 각 금속인 코발트, 니켈 및 구리의 무기 및 유기산 조건에서의 침출실험을 진행했다. 얻어진 각 금속의 침출결과에 따라, 금속합금상의 침출 실험을 진행하여 과산화수소를 혼합한 염산용액에서 최적 침출조건을 얻었으며, 비슷한 화학적 성능을 가진 코발트와 니켈을 분리하기 위해 유기인산계 추출제와 최근 친환경적 용매로 각광받고 있는 이온성액체를 합성시켜 각 코발트(II)와 니켈(II)의 선택적 분리를 실험했다. NH4SCN과 이온성액체를 합성시켜 코발트(II)의 선택적 추출조건을 달성했다. 이 후에 황산용액에서 코발트(II), 니켈(II) 및 구리(II)의 침출용액에서 용매추출 실험을 진행하여 Cyanex301의 구리(II)의 선택적 추출 및 ALi-SCN으로 코발트의 선택적 추출조건을 얻어냈으며, 이전의 연구에서 얻어낸 금속합금상의 침출 조건을 적용하여 얻어진 염산 침출액을 바탕으로 각 금속의 분리를 위한 실험을 진행했다. 용매추출법을 사용하여 각각 Cyanex 301, D2EHPA, ALi-SCN으로 철(III), 구리(II) 및 코발트(II)를 선택적으로 분리 하였으며, 남겨진 소량의 망간(II)을 분리하기 위해 NaClO를 첨가하여 MnO2상으로 얻어졌지만 소량의 규소(IV)가 남겨졌다. 수상의 니켈(II) 라피네이트의 소량의 규소(IV)는 니켈(II)의 순도를 낮추므로 이를 분리하기 위해서 PAM과 탄산나트륨 및 옥살산나트륨을 첨가했다. 탄산나트륨첨가시 규소(IV)가 같이 침전되었으며, 옥살산나트륨 첨가시 순도 99.99% 이상을 지닌 니켈옥살산염으로 회수가 가능하다. 본 실험결과를 바탕으로 폐리튬이온배터리의 용융환원된 금속합금상의 각 금속의 회수를 위한 습식제련공정을 개발할 수 있다. Lithium-ion batteries are rapidly increasing in usage due to the development of portable devices such as mobile phones and laptops and the expansion of the electric vehicle market due to excellent performance such as high energy and power density. will be created In addition, a lot of valuable metals are contained in waste lithium-ion batteries, and there is a lot of interest in recovering them. As a recent treatment method for spent lithium-ion batteries, a combination of dry smelting and hydrosmelting is used to recover lithium and aluminum as oxidized slag at a high temperature using a dry method, and cobalt, nickel and copper are molten-reduced to obtain a metal alloy phase. Accordingly, in order to separate the target metals of cobalt, nickel, and copper on metal alloys by hydrometallurgical methods, the recovery of the target metals was investigated by leaching, solvent extraction, and precipitation methods. In this paper, leaching experiments of cobalt, nickel and copper, each of the metals on the obtained metal alloy, were conducted under inorganic and organic acid conditions. According to the leaching results of each metal obtained, an optimal leaching condition was obtained in a hydrochloric acid solution mixed with hydrogen peroxide by conducting a leaching experiment on the metal alloy. Each extraction experiment was carried out by synthesizing an ionic liquid, which has been spotlighted as an eco-friendly solvent, and the extraction experiment was carried out by synthesizing NH4SCN and an ionic liquid. After that, a solvent extraction experiment was performed on the leaching solution of Co(II), Ni(II) and Cu(II) in sulfuric acid solution to obtain the separation conditions for each metal, and the leaching conditions for the metal alloy phase obtained in the previous study were applied Based on the obtained hydrochloric acid leachate, an experiment was conducted for the separation of each metal. Using a solvent extraction method, Fe(III), Cu(II) and Co(II) were selectively separated with Cyanex 301, D2EHPA, and ALi-SCN, respectively, and NaClO was added to separate the remaining small amount of Mn(II). It was obtained as a MnO2 phase but a small amount of Si(IV) was left behind. A small amount of Si(IV) in the Ni(II) raffinate in the aqueous phase lowers the purity of Ni(II), so PAM, sodium carbonate and sodium oxalate were added to separate it. When sodium oxalate was added, it was recovered as nickel oxalate having a purity of 99.99% or more. Based on the experimental results, it is possible to develop a hydrometallurgical process for recovery of each metal in the smelting reduced metal alloy phase of a spent lithium-ion battery.

위상압축상태를 이용한 단일 광자 양자 키 분배 기법 분석

문현승 고려대학교 대학원 2021 국내석사

본 논문은 양자역학적 특성을 이용하는 키 분배 기법인 양자 키 분배 기법에서 일반적으로 사용되는 입력 상태인 결맞음 상태를 변형하여, 위상압축상태를 양자 키 분배 시스템의 입력으로 사용하는 기법을 제안한다. 단일 광자 양자 키 분배 기법의 경우 광자 단위로 정보를 실어서 키 분배를 진행하게 되는데, 이 때 전송거리가 멀어질수록 광자가 광 케이블이나 소자에 흡수되거나 편광이 틀어져 원하는 키 전송을 할 수 없게 되는 경우가 발생한다. 이를 보완하기 위해 광자를 다수 입력하여 방출하게 되면, 도청자의 PNS(Photon-Number-Splitting) 공격에 취약해지게 되는 단점이 있다. 하지만, 이러한 PNS 공격을 완화해주는 decoy 기법을 차용한다면, 단일 광자가 사용되지 않는 경우에도 부분적으로 보안성을 유지할 수 있음이 알려져 있다. 이러한 아이디어에서 착안하여, 결맞음 상태를 위상압축상태로 변형하게 된다면 같은 평균 광자 수를 가진 상태임에도 상대적으로 다중 광자 상태가 많이 입력으로 사용되게 되어 전송 거리 측면에서의 이득이 있다. 즉, 비밀 키 생성율 측면에서도 기존의 결맞음 상태 기반 기법 대비 이득이 있음을 본 논문을 통해 확인할 수 있다. 본 논문을 통하여 제안된 위상압축상태 기반의 양자 키 분배 기법을 토대로 보다 먼 전송거리를 가지는 양자 키 분배 환경 구성에 큰 기여를 할 수 있을 것으로 기대된다.

Development of the distraction osteogenesis model for rat mandibular inferior border and alveolar bone

문현승 Graduate School, Yonsei University 2010 국내석사

Osteogenic distraction is defined as surgical procedure which creates new bone and adjacent other tissues including gingiva, skin, muscle, tendon, blood vessels and nerves by incremental traction of osteomized bone edges. By virtue of it’s advantages, treatment effects of distraction osteogenesis on patients have been reported. In recent, even the mechanism of distraction osteogenesis has been extensively applied to alveolar bone area as an alternative to the traditional treatment. Tremendous development of the technique has been achieved, but much of molecular events involved in the process remained still questionable. The aim of this study is to establish an experimental rat model for distraction osteogenesis on mandible and alveolar bone concurrently for investigating histologic and radiographic analysis and to develop the device for various conditions of distraction. The results of this study were as follows. 1. Micro CT analysis was performed for the anatomical structure of rat mandible and provided the guides for the location and design of osteotomy and positioning the bone screws stabilizing the distraction device. 2. The rat distraction osteogenesis model for mandibular inferior border and alveolar bone was successfully established on the basis of the protocols used in this study. The protocols contain 5 days of latency period, distraction rate of 0.20 mm/day, at a single session, and 4 weeks of consolidation phase. 3. New bone formation of the rat model occurred by combination of two modes. Intramembranous ossification was predominant at the end of distraction period, while endochondral ossification was observed at the center of distraction gap at the end of 4 weeks of consolidation period. The mandibular inferior border and alveolar distraction model for rats was successfully established in this study. This model can be applied to various conditions related to the distraction osteogenesis and provide knowledge for improvements of distraction osteogenesis treatment for patients.