• 자원리싸이클링
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• 제26권3호
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• pp.47-52
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• 2017

중액선별(HMS, heavy medium separation)을 통해 회수된 인운모(lepidolite) 정광(Li: 2.3%)으로부터 리튬을 수 침출하기 위해 황산칼슘 반수화염(CSH, calcium sulfate hemihydrate, $CaSO_4{\cdot}1/2H_2O$)과 혼합분쇄하여 기계화학적 효과를 연구하였다. 인운모를 CSH와 함께 고강도 분쇄한 결과, 리튬의 침출율이 4.48%에서 93.5%로 급격히 증가하였다. 이는 고강도 혼합분쇄 과정 중 발생되는 기계화학적 효과로 인해 결정구조가 파괴되면서 인운모와 CSH의 혼합물이 새로운 화합물로 형성되어 나타난 결과로 판단된다. 결과적으로 인운모로부터 상온에서 리튬의 수 침출이 가능함을 확인하였다.

• 대한토목학회논문집
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• 제33권4호
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• pp.1683-1691
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• 2013

콘크리트 표면절삭 작업은 포장면의 노화 또는 파손으로 인한 보수작업과 그루빙(Grooving) 시공을 통한 포장면의 배수능력을 강화하거나 평탄성을 확보를 위하여 자주 적용되는 공법이다. 그러나 그 작업특성이 노동집약적이고 분진, 슬러지, 소음 등으로 인한 유해한 작업환경을 보유하고 있으며 장비를 다루는 기능공의 숙련도에 따라 생산성 및 절삭품질의 편차가 큰 경향이 있다. 따라서 장비 조종자가 각종 위험에 노출되지 않도록 하기 위한 원격조종 콘크리트 표면절삭 장비 개발이 필요하다. 원격 조종 환경에서는 조종자가 객관적인 절삭 품질을 확인함과 동시에 장비가 계획 경로에 따라 작업이 올바르게 수행되고 있는지를 확인할 수 있도록 하는 지원시스템이 필요케되는 바, 본 연구에서는 머신비전 시스템(Machine Vision System)과 GPS를 적용하여 네트워크 카메라로 촬영한 절삭면의 이미지를 디지털 영상처리(Image Processing)과정을 거쳐 객관적이며 품질관리 프로세스가 자동화된 시스템을 구축하였다. 또한 장비의 현재 위치와 방향, 속도, 계획된 경로와의 오차정보 그리고 작업의 진척도 등을 종합적으로 산출하여 워크 스테이션에 표시함과 동시에 머신 비전 시스템에 의한 작업 품질 정보와의 통합을 위한 프로그램을 개발하였으며, 현장 적용 테스트를 통해 본 기술을 검증하였다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.983-986
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• 2007

콘크리트 표면절삭 작업은 콘크리트 표면의 평탄성 및 부착성을 필요로 하는 공사에서 빈번히 사용되고 있으나 작업형태가 노동집약적이며, 유해한 작업환경을 보유하고 있다. 또한 장비를 다루는 기능공의 숙련도에 따라 생산성 및 절삭품질의 편차가 큰 경향이 있다. 그러므로 주변 환경오염 방지와 장비 조종자가 위험에 노출되지 않도록 하기 위한 원격조종 콘크리트 표면절삭 장비 개발이 요구된다. 그러나 원격 조종 시스템에서 조종자가 절삭면의 품질을 측정하기 난해하고 품질에 대한 객관적인 판단을 내리기가 어려우므로, 본 연구에서는 머신비젼시스템(Machine Vision System)을 적용하여 네트워크 카메라로 촬영한 절삭면의 이미지를 디지털 영상처리(Image Processing)과정을 거쳐 그 결과를 그래픽 MMI(Man-Machine Interface) 프로그램에 표현함으로써 품질관리 시스템을 구축하였다. 머신비전 알고리즘은 콘크리트 절삭면의 디지털 영상처리 알고리즘을 의미하며 본 논문에서 제안된 알고리즘을 적용하여 콘크리트 절삭면의 객관적인 품질관리 기준을 제시하고자 한다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.624-628
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• 2003

Lanthanum oxyfluoride can be synthesized by mechanochemical (MC) reaction between lanthanum oxide ($La_2O_3$) and polytetrafluoroethylene (PTFE, ($({CF_2CF_2}_n)$) in air using a planetary mill. MC reaction between the two materials induced from intensive grinding operation. The MC reaction is almost finished by 240min, and the products ground for 240min or more are composed of LaOF, amorphous $La(CO_3)F$ and amorphous carbon (C). Heating this MC reaction products at $600^{\circ}C$ enables us to eliminate amorphous C and decompose $La(CO_3)F$ into LaOF, so that pure LaOF material can be obtained as the final product. The average particle size of the final product (purified LaOF) is around few ten nanometers.

• 자원리싸이클링
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• 제27권4호
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• pp.57-64
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• 2018

알칼리화합물과의 기계화학반응을 통해 산화물로부터 텅스텐(W)과 바나듐(V) 성분의 수 침출 특성을 조사하였다. 기계화학반응은 알칼리화합물의 혼합율과 분쇄시간을 변화시키면서 실시하였고, 그 결과, 수용성 용해특성의 $Na_2WO_4$와 $NaVO_3$가 각각 생성되었으며 수 침출에 의한 W, V의 침출특성은 알칼리화합물의 혼합율과 분쇄시간에 비례하여 증가하였다. 99% 이상의 침출율은 각각 30분 (W), 5 분 (V)의 짧은 기계화학적 처리를 통하여 달성되었다. 이러한 기계화학적 처리를 통하여 텅스텐, 바나듐산화물로부터 수 침출에 의한 추출이 가능하였고, 이 공정은 탈질촉매로부터 텅스텐, 바나듐의 선택적 회수에 적용될 수 있다.

• 한국기계가공학회지
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• 제7권3호
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• pp.67-74
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• 2008

Polycrystalline diamonds(PCD) tools are widely used in machining a large variety of advanced materials. However, the manufacture of PCD tool blanks is not an economical process. The shaping of PCD blanks with conventional machining methods(such a grinding) is long, labor-intensive process. This paper reports experimental investigation of the influence of electrical machining conditions on the metal removal rate of WEDM of PCD. Experimental results show that the longer pulse-on time and the shorter pulse-off time increase the metal removal rate and worsen the surface quality. The smaller grain size of diamond yields the metal removal rate and shows the better surface quality. Higher electrical conductivity of water yields worse surface roughness.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.1050-1054
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• 2006

There have been intensive and continuous efforts in the field of DLC coating process because of their feature, like high hardness, high elasticity, abrasion resistance and chemical stability and have been applied widely the industrial areas. In this research, optimal grinding condition was investigated using Microlens Process Machine for the development of aspheric glass lens which is to be used for mobile phone module with 3 mega pixel and 2.5X optical zoom, and tungsten carbide(WC) mold cote was manufactured using high performance ultra precision machining and the effects of DLC coating on the form accuracy(PV) and surface roughness(Ra) of WC mold core was evaluated.

• 대한치과기공학회지
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• 제37권3호
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• pp.131-144
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• 2015

Purpose: This study set out to propose plans for more efficient and effective clinical practice by investigating the current state of clinical practice in the field of dental technology and thus provide basic data to develop pre- and post-education programs for clinical practice. Methods: The subjects include dental technicians at dental technical laboratories that were appointed as the place of clinical practice by the Department of Dental Technology of G University. The survey period spanned from December 22, 2014 to January 20, 2015. Total 250 questionnaires were distributed to them, and 190(76.0%) were returned. After excluding 23 whose answers were uncertain or seemed to lack reliability, total 167(66.8%) were used in final analysis. Results: 1. The most frequent practice the student did during clinical practice was articulator attachment, which was followed by pin operation or model making, one's own task and practice, sand and crow sculpturing, burying, casting, and grinding. 2. In case of going through the entire process, porcelain had the most students at 39(23.4%), being followed by crown & bridge at 28(16.8%), clinical model at 23(13.8%), full denture at 17(10.2%), and partial denture at 17(10.2%) in the order. 3. Of the students, 59.8%(30.5% for reinforced basic practice; 29.3% for intensive practice education) said that intensive practice education should be reinforced in school; and 22.3% said that intensive theory and practice education was needed, which indicates that 82.6% voiced their opinion of reinforcing education around practice. 4. The students felt that they lacked diligence, passion, and theoretical knowledge somewhat and were relatively good at clinical adaptation and operational skills. Conclusion: The findings show that the students felt an absolute lack of practice education as the school education was focused on theory and national exams in the field of dental technology, thus raising a need to reinforce practice education. Of all the respondents, 62.9% said there was a need to improve the current education with a focus on jobs. In future, education of dental technology should work to bring up able dental technicians that can perform in clinical dental technology right after graduation by reinforcing job-based practice education.

• 식물병연구
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• 제20권1호
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• pp.15-20
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• 2014

A rapid, user-friendly and simple immune-chromatographic dipstick kit named 'rapid immune-gold strip' (RIGS) kit was developed in a novel single strip format to detect on-site detection of Tomato spotted wilt virus (TSWV). Immunoglobulin G (IgG) from polyclonal antisera raised in rabbits against TSWV was purified through protein-A affinity chromatography and then the purified TSWV-IgG was conjugated to colloidal gold nano-particles which served as a test line on nitrocellulose membrane. Protein A that non-specifically binds to TSWV antibody was used as a control line on the same strip. The diagnosis process with the TSWV-RIGS involves simply grinding the suspect plant sample in a bag that contains the extraction buffer and inserting the strip the bag. Results can be seen in 2-5 minutes. The flow of the complexes of gold particles coated with TSWV-IgG and a crude sap from TSWV-infected pepper, tobacco and tomato plants resulted in intensive color formed on the test lines proportional to the concentrations of TSWV. The RIGS-TSWV kit did not show any cross-reactions against other tomato-infecting viruses unrelated to TSWV. These results indicate that the TSWV-RIGS kit is highly sensitive and is not required for laboratory training and experience prior to testing. The TSWV-RIGS kit is suitable for on-site detection of suspect TSWV-infected plants as well as for laboratory diagnosis.

• 한국건축시공학회지
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• 제2권2호
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• pp.129-134
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• 2002

The strength and durability of concrete are affected by various factors such as the quality of material, mixing ratio, construction, the method of cure, time elapsed. the condition of test and etc., it is very difficult to pre-estimate the strength of concrete with the use of experimental specimen. The domestic standard of specimen cylindrical type and its sizes are both l0cm$\times$20cm and 15cm$\times$30cm, which are prescribed in KS F2405, and the loading speed is prescribed to test with 2~3kgf/$\textrm{cm}^2$ per second. The loading speed should have great effect on the compressive strength, but in reality in the construction site sometimes the loading speed is applied so dubiously that the value of the compressive strength can be unreliable. And the cross sectional area of a specimen should be level and smooth, otherwise it can be broken at a lower stress than the real strength through the eccentric or intensive working of the load. Capping should be carried out in order to measure the strength correctly. And used for capping are various materials such as capping compound, cement glue, plaster, mechanical grinding and etc. In this study, therefore, I have carried out an experiment on the relationship among the loading speed, the ratio of height to diameter of specimen, the method of capping, and the compressive strength, for the efficient quality control of concrete structures. So this study has been purposed to provide some basic data that can be used effectively at construction sites.