• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2006년도 추계공동학술대회
• /
• pp.373-383
• /
• 2006

Logistics is one of the most important factors to manage a stream of materials in economic environment. Establishing effective logistics system needs to consider some constraints which are fluctuation of materials volume, a long distance between makers and consumers, one way logistics and small quantity batch production. It is estimated that Unit Load System should be a powerful method to cope with those problems. It helps to realize the key issues which are Standardization and Logistics Pool System The Material Unification of Logistics System is able to participate in all kinds of industries including manufacturing, distribution and logistics. This system has some merits which are a long distance transportation cost down, product recovery, and treatment in the unbalance of demand and supply caused by unstable materials volume. Four strategies of Material Logistics Model are Packing Rationalization, Logistics Pool System, JIT System application and establishing effective infrastructure. The Material Unification Of Logistics System based on Unit Load System achieves efficiency of logistics and largely decreases moving cost.

• 한국환경복원기술학회지
• /
• 제20권6호
• /
• pp.35-50
• /
• 2017

This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

• 공업화학
• /
• 제26권3호
• /
• pp.377-380
• /
• 2015

본 연구에서는 p-diiodobenzene (PDIB)으로부터 p-phenylenediamine (PPD) 합성 후 생성되는 부산물인 $NH_4I$를 PDIB 합성의 원료로 재활용하기 위하여 $I_2$ 회수 공정의 최적화에 관한 연구를 진행하였다. 양이온교환수지를 사용하여 $NH_4I$ 시약 용액으로부터 $I_2$ 회수에 관한 연구를 진행하였고 양이온교환수지의 파과곡선을 통해 파과점 및 관류교환용량을 조사하였다. 회수되는 요오드의 수율 및 순도 향상을 위해 $NH_4I$의 공급용액 및 산화제($H_2O_2$)의 농도 변화, 상온과 저온 건조공정 그리고 산화시간에 따른 순도와 수율을 측정하여 $NH_4I$ 용액으로부터 요오드를 회수하는 공정의 최적조건을 확립하였다. 또한 산화공정 후 발생하는 여액을 재사용하는 과정을 도입하여 실험한 결과 수율 94.96%, 순도 96.65%의 $I_2$를 회수할 수 있었다.

• 한국결정성장학회지
• /
• 제30권2호
• /
• pp.55-60
• /
• 2020

기존 연구에서 본 연구자들은 여러 가지 리튬 함유 용액으로부터 탄산리튬 분말 제조에 대하여 보고하였으며, 이중에서 수산화리튬 용액과 CO₂ 가스와의 반응이 열역학적으로 탄산리튬 생성이 가능하고 89.4 %의 회수율을 나타내었다. 본 연구에서는 수산화리튬 용액과 CO₂ 가스와 기액반응에 있어서 초음파에너지를 가하여 탄산리튬 분말을 제조하는 실험을 실시하였다. 실온에서 탄산리튬 생성 반응에 초음파를 가하였을 경우에 리튬의 회수율은 83.8 %이었으며, 60℃에서 초음파를 가하면 99.9 %로 회수율이 급격하게 증가되었다. 또한 초음파 에너지를 가하지 않을 경우의 입자 크기는 D50에서 약 87.7 ㎛이었으며, 초음파를 가한 경우에는 D50이 약 8.4 ㎛로 급격하게 감소하는 결과를 얻었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.289.2-289.2
• /
• 2016

In-Ga-Zn-O(IGZO) receive great attention as a channel material for thin film transistors(TFTs) as next-generation display panel backplanes due to its superior electrical and physical properties such as a high mobility, low off-current, high sub-threshold slope, flexibility, and optical transparency. For the purpose of fabricating high performance IGZO TFTs, a thermal recovery process above a temperature of $300^{\circ}C$ is required for recovery or rearrangement of the ionic bonding structure. However diffused metal atoms from source/drain(S/D) electrodes increase the channel conductivity through the oxidation of diffused atoms and reduction of $In_2O_3$ during the thermal recovery process. Threshold voltage ($V_{TH}$) shift, one of the electrical instability, restricts actual applications of IGZO TFTs. Therefore, additional investigation of the electrical stability of IGZO TFTs is required. In this paper, we demonstrate the effect of Ti diffusion and modulation of interface traps by carrying out an annealing process on IGZO. In order to investigate the effect of diffused Ti atoms from the S/D electrode, we use secondary ion mass spectroscopy (SIMS), X-ray photoelectron spectroscopy, HSC chemistry simulation, and electrical measurements. By thermal annealing process, we demonstrate VTH shift as a function of the channel length and the gate stress. Furthermore, we enhance the electrical stability of the IGZO TFTs through a second thermal annealing process performed at temperature $50^{\circ}C$ lower than the first annealing step to diffuse Ti atoms in the lateral direction with minimal effects on the channel conductivity.

• 한국축산식품학회지
• /
• 제35권4호
• /
• pp.466-472
• /
• 2015

A rapid and simple analytical method, using liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed to detect myo-inositol (MI) in infant formulas. For protein removal: acid hydrolysis and lipid removal through organic solvent extraction. The operating conditions for instrumental analysis were determined based on previously reported analogous methods that used LC-MS/MS. Quantitative analysis was used for the detection limit test, infant formula recovery test, and standard reference material (SRM) 1849a to verify the validity of our LC-MS/MS analytical method, which was developed to quantify MI. For validation, the results of our method were compared with the results of quantitative analyses of certified values. The test results showed that the limit of detection was 0.05 mg/L, the limit of quantitation was 0.17 mg/L, and the method detection limit was 17 mg/kg. The recovery test exhibited a recovery between 98.07-98.43% and a relative standard deviation between 1.93-2.74%. Therefore, the result values were good. Additionally, SRM 1849a was measured to have an MI content of 401.84 mg/kg and recovery of 98.25%, which is comparable to the median certified value of 409 mg/kg. From the aforementioned results, we judged that the instrumental analysis conditions and preparation method used in this study were valid. The rapid analytical method developed herein could be implemented in many laboratories that seek to save time and labor.

• 한국전자파학회논문지
• /
• 제18권4호
• /
• pp.423-429
• /
• 2007

위성 DMB용 중계기는 위성으로부터 수신된 2.304 MHz의 기준 신호를 이용하여 10 MHz의 클럭 신호를 재생하여 시스템 동기 신호로 사용한다. 본 논문에서는 기준 신호가 잡음에 의해 흔들리거나 끊기더라도 안정된 신호를 재생할 수 있는 클럭 재생 모듈을 제안하였다. 제안된 모듈은 기존 방식에 비해 저가로 구현이 가능하며, 정기적인 주파수 조정이 필요 없는 장점이 있다. 본 논문에서는 클럭 재생용 IC를 CPLD를 이용하여 구현하였고, lock time을 짧게 하면서 동시에 출력 주파수의 hold over 시간을 늘리기 위해 새로운 루프 필터를 적용하였다. 제작된 모듈은 출력 주파수의 안정도가 0.01 ppm 이내일 경우 hold over 시간이 11초, 출력 전력은 -0.66 dBm, 위상잡음은 100 Hz 오프셋에서 -113 dBc/Hz로 측정되었다.

• 자원리싸이클링
• /
• 제21권4호
• /
• pp.26-34
• /
• 2012

제품을 제조하는 대부분의 공정에서는 불량품이나 스크랩 등의 폐기물이 발생한다. 전기전자 제품을 생산하는 공정에서도 금속을 함유한 복합물질의 폐기물이 다량 발생하며, 이로부터 금속을 회수하는 것은 자원재활용의 측면 뿐 아니라 매립 등의 처리에 대한 환경부담을 줄이는 효과가 있다. 이 논문에서는 전기전자 제품을 제조하는 공정에서 발생하는 불량품을 포함한 폐기물로부터 금속을 회수하는 기술에 대하여 1975년부터 2011년까지 공개/등록된 미국, 일본, 유럽, 한국의 특허와 SCI급 논문을 조사하였다. 키워드를 이용하여 조사하였고 필터링 하여 특허와 논문을 수집하여 연도별, 국가별, 기관별, 기술별로 분석하였다. 분석결과, 특허의 경우는 한국, 일본, 미국 순으로 많이 제출하였고 논문의 경우에는 대만, 미국 순이었다.

• Carbon letters
• /
• 제28권
• /
• pp.87-95
• /
• 2018

This study examined the influence of operating parameters on the electrosorptive recovery system of lithium ions from aqueous solutions using a spinel-type lithium manganese oxide adsorbent electrode and investigated the electrosorption kinetics and isotherms. The results revealed that the electrosorption data of lithium ions from the lithium containing aqueous solution were well-fitted to the Langmuir isotherm at electrical potentials lower than -0.4 V and to the Freundlich isotherm at electrical potentials higher than -0.4 V. This result may due to the formation of a thicker electrical double layer on the surface of the electrode at higher electrical potentials. The results showed that the electrosorption reached equilibrium within 200 min under an electrical potential of -1.0 V, and the pseudo-second-order kinetic model was correlated with the experimental data. Moreover, the adsorption of lithium ions was dependent on pH and temperature, and the results indicate that higher pH values and lower temperatures are more suitable for the electrosorptive adsorption of lithium ions from aqueous solutions. Thermodynamic results showed that the calculated activation energy of $22.61kJ\;mol^{-1}$ during the electrosorption of lithium ions onto the adsorbent electrode was primarily controlled by a physical adsorption process. The recovery of adsorbed lithium ions from the adsorbent electrode reached the desorption equilibrium within 200 min under reverse electrical potential of 3.5 V.

• 대한기계학회논문집B
• /
• 제40권5호
• /
• pp.289-296
• /
• 2016

리튬이온전지 양극활물질 제조공정의 용제로 사용되는 NMP(N-Methyl-2-Pyrrolidinone)는 전량수입에 의존하고 있으며 BASF와 ISP의 독과점에 따라 높은 가격을 유지하고 있다. 이로 인해 대부분의 리튬이온전지 제조업체들은 건조과정에서 배기되는 공기 중에서 NMP를 회수한 후 재사용하는 방식을 이용하고 있다. 국내에서는 주로 NMP의 친수성을 이용해 흡수탑에서 회수하는 흡수법을 사용한다. 이 방식으로 회수된 NMP의 순도는 80% 수준이며, 처리된 가스의 수분 함유량이 높아 100% 배기할 수밖에 없는 문제점이 있다. 본 연구에서는 냉각응축법과 농축법을 복합 구성하여 NMP 회수율이 99.6%, 회수된 NMP 순도가 96.1%인 하이브리드형 NMP 회수시스템을 개발하였다.