폐 EPS개생 굵은골재를 이용한 경량콘크리트 개발에 관한 연구

박차원,최봉철,안재철,강병희 대한건축학회 2000 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.20 No.1

콘크리트 구조물의 완전순환이용을 위한 폐콘크리트계 미분말의 재생시멘트 활용 기술 연구

박차원,안재철,강병희 한국건축시공학회 2004 한국건축시공학회지 Vol.4 No.3

The purpose of this study is development of technique to use cementitious powder as recycle cement produced from deteriorated Concrete waste which has a large quantity of calcium carbonate. Therefore, after having theoretical consideration based on the properties of high-heated concrete and concerning about neutralization of Concrete, we analysis chemical properties of ingredients of cementitious powder. After making origin cement paste, then processing the accelarated carbonation, we consider the properties of hydration and chemical properties of cementitious powder under various temperature conditions.As a result of the thermal analysis, the CaCO3 content of cementitious powder would affect decision of heat temperature to recover its hydrated ability because CaCO3 content is increased when neutralization is progressed. And as a result of XRD analysis, in case of origin powder of non-neutralized paste, CaO peak is found at 700℃. but, heat temperature to generate CaO would increase when the content of neutralized ingredients is increased. Finally, recycle cement heated at 700℃ 120min. shows the best compressive strength when the content of neutralized ingredients in recycle cement is less then 50%.

폐콘크리트 미분말을 이용한 재생시멘트 모르터의 중성화 특성

박차원,강병희,안재철 한국건축시공학회 2006 한국건축시공학회지 Vol.6 No.4

Recently, there have been many studies about recycling cementitious powder from concrete waste(hereinafter referred to as waste powder), generated after recycle aggregate production. Previous studies showed that when the heating process of waste powder at 700℃, Ca(OH)2 in paste is dehydrated making possible the restoration of hydraulic properties. Recycled cement with hydraulic properties restored is thought to be re-hydrated through the mechanism of hydration, which is almost similar in Portland cement. This clearly suggests that the hydrate of recycled cement is alkali in type. Like in general concrete, if recycled cement is used as a structural material, resistance performance against carbonation or neutralization by CaCO3 in air probably would be most influential to the life of steel-reinforced concrete structure. Thus the purpose of this study is to make an experimental review on chemical properties of recycled cement, manufactured with concrete waste as base material, and investigate the durability of concrete using recycled cement through evaluating the cement’s performance of resistance to carbonation in accordance with its accelerating age. Based on its results, further, the study seeks to provide basic information about ways of utilizing recycled cement.

혼화재료를 혼입한 재생시멘트 모르터의 수화특성에 관한 연구

박차원,강병희 한국건축시공학회 2004 한국건축시공학회지 Vol.4 No.4

The purpose of this study was the development of a recycling process to recover the hydraulic properties of hydration products which account for a large proportion of cementitious powder from concrete waste. This process was performed to recycle cementitious powder as recycle cement. Therefore, after the theoretical consideration of the properties of recycle process of recycled aggregates and cementitious powder, we investigated the hydraulic properties of cementitious powder under various temperature conditions in hardened mortar which was modeled on concrete waste. And we analyzed properties of chemical reactions of recycled cement with admixture materials such as Fly-Ash, Blast Furnace SlagAs a result of the experiment, the most effective method to recover hydraulic properties of the cementitious powder from concrete waste was condition of burning at 700℃ for 120 minute. And it is shown that the fluidity of mortar was decreased rapidly when the burning temperature of recycle cement was increased. However, the compressive strength and fluidity were improved significantly when admixture materials such as Fly-Ash or Blast Furnace Slag was added.

폐콘크리트의 순환이용을 위한 폐미분말의 재활용 기술

박차원,강병희 한국건축시공학회 2005 한국건축시공학회지 Vol.5 No.3

Recently, there have been many studies seeking towards the utilization of cementitious powder from concrete waste as recycled cement. However, most of the studies actually have been researches about the reuse of mortar or paste, not concrete waste. In fact, either mortar or paste is quite different from a real concrete waste in terms of age and mixture. Thus the purpose of this study is to examine basic physical properties of recycled cement, manufactured with cementitious powder from concrete waste, and analyze differences in chemical and hydraulic properties of the cement and its tested model. As a result of the chemical analysis, recycle cement is composed mainly of CaO and SiO2, and that it is even lower in the content of CaO than Portland cement, which is also supported by previous studies. But, Differently from previous studies, calcining temperature of 650 was found an optimal condition under which cementitious powder from concrete waste could restore its hydraulic properties.

廢콘크리트의 再活用을 위한 骨材 界面分離에 관한 實驗的 硏究

박차원(Park Cha-Won),강병희(Kang Byeung-Hee) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.10

The purpose of this study is to provide the basic data on the optimum method for interfaclal separation for an effective recycle of concrete waste by using the thermal properties of concrete.<br/> Therefore, this study is proceeded by dividing the interface of concrete into cement paste and fine aggregates or mortar and coarse aggregate, considering the aspect of recycled cement and aggregate as the recycling use of concrete waste.<br/> As results of experiment, in case of recycle cement, the interfaciaI separation is easily appeared, yet it is shown that the mixed amount of powder included in fine aggregate greatly decreases.<br/> But, in case of recycle coarse aggregate, the effect of interfacial separation by preliminary heating is predominant. Especially, the bonding rate of mortar is the lowest during cycling heating 5 times every 120 minutes at 300℃.<br/> Hence, it is considered that it will be an excellent effect of quality control when applied to recycle coarse aggregate which is now in a phase of making practical based on the result of this research.

Study on terahertz (THz) photoconversion technology based on hyperfine energy-level splitting of Positronium (Ps) generated from relativistic electron beams

민선홍,박차원,조일성,김민호,마숙활,황원택,김경민,박승우,이민용,이교철,이용진,홍봉환 대한방사성의약품학회 2020 Journal of radiopharmaceuticals and molecular prob Vol.6 No.2

In the state of Positronium (Ps), which is an unstable material created by the temporary combination of electrons and positrons, the imaging technology through photo-conversion methodology is emerging as a new research theme under resonance conditions through terahertz electromagnetic waves. Normally, Positronium can be observed in the positron emission computed tomography (PET) process when an unstable, separate state that remains after the pair annihilation of an electron and a positron remains. In this study, terahertz (THz) waves and Cherenkov radiation (CR) are generated using the principle of ponderomotive force in the plasma wakefield acceleration, and electrons and positrons are simultaneously generated by using a relativistic electron beam without using a PET device. We confirm the possibility of Positronium photoconversion technology in terahertz electromagnetic resonance conditions through experimental studies that generate an unstable state. Here, a relativistic electron beam (REB) energy of 0.5 MeV (γ=2) was used, and the terahertz wave frequencies is G-band. Meanwhile, a THz wave mode converting three-stepped axicon lens was used to apply the photoconversion technology. Through this, light emission in the form of a luminescence-converted Bessel beam can be verified. In the future, it can be used complementarily with PET in nuclear medicine in the field of medical imaging.

Transverse Beam Emittance Measurement Using Quadrupole Variation at KIRAMS-430

안동현,한가람,박차원 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.3

In order to produce a 430 MeV/u carbon ion (12C6+) beam for medical therapy, the KoreaInstitute of Radiological & Medical Sciences (KIRAMS) has carried out the development of asuperconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, anEnergy Selection System (ESS) is located to modulate the fixed beam energy and to drive theion beam through High Energy Beam Transport (HEBT) into the treatment room. The beamemittance at the ion beamline is to be measured to provide information on designing a beam withhigh quality. The well-known quadrupole variation method was used to determine the feasibility ofmeasuring the transverse beam emittance. The beam size measured at the beam profile monitor(BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied beingtaken under various transport condition of varying quadrupole magnetic strength. Two differentmethods where beam optics are based on the linear matrix formalism and particle tracking with a3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport thebeam. The fittings for the transformation parameters are used to estimate the transverse emittanceand the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematicstudies, we conclude that within the uncertainty the estimated emittances are consistent with theones calculated by using Monte Carlo simulations.

테라헤르츠파 자기공명 기반 생체 내 신호 전달을 통한 치료 응용

민선홍,조일성,박차원,김병수,임희중,이민영,김은주,박건식 한국전자파학회 2018 전자파기술 Vol.29 No.5

Consideration of the benefits of using a high current accelerator in BNCT

조일성,민선홍,박차원,김민호,이교철,이용진,홍봉환,임상무 대한방사성의약품학회 2020 Journal of radiopharmaceuticals and molecular prob Vol.6 No.1

Boron Neutron Capture Therapy (BNCT) has the advantage of selectively removing cancer cells ingesting boron compounds. In this study, the benefits for treatment time and boron compound injection dose were compared between current neutron sources and a high current neutron sources to be developed in near future. The time-activity curve (TAC) of GBM (Glioblastoma) for one bolus injection was obtained by applying modified 3 compartment model. The treatment time was determined for an accelerator-based neutron sources at the present time and a high current accelerator based neutron source to be developed in the near future. In the case of the double amount of IAEA-recommended neutron flux, the treatment time was shortened to 15 minutes. In the case of high current accelerators, which are five times the amount of IAEA-recommended neutron flux, the irradiation time is within 5 minutes. The use of a high current accelerator based neutron source in BNCT is advantageous in terms of treatment time. In addition, it can increase the efficiency of use of neutrons and reduce the boron compound injection dose to patients, thus reducing pharmacological toxicity.