• 펄프종이기술
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• 제47권6호
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• pp.106-112
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• 2015

Many researchers have proposed analytical methods to measure the adsorption of di-sulpho fluorescent whitening agents (D-FWAs), but practical methods for D-FWA utilization in an actual paper mill have not been established. In particular, the D-FWA adsorption behavior must be monitored in paper mills to ensure the effective use of D-FWAs. This study used the zeta-potential of pulps as an indicator of the adsorption behavior of a D-FWA. We identified the relationship between the actual adsorption of the D-FWA and the zeta-potential of the pulps as a function of D-FWA addition. zeta-potential measurements were then used to analyze the D-FWA adsorption behavior under different conditions of pulp type, conductivity, and pH. The actual adsorption of a D-FWA was proportional to the ${\Delta}zeta-potential$ of the pulps (i.e., the difference between the zeta-potential of a pulp containing no D-FWA and one containing the D-FWA). The ${\Delta}zeta-potential$ of the pulps was therefore adopted for adsorption analysis. A higher adsorption of the D-FWA was observed onto Hw-BKP than onto Sw-BKP because of the shorter fiber length and higher fines content of Hw-BKP. A high conductivity and an acidic pH decreased the D-FWA adsorption because of direct effects of high ion concentrations and low pH on the D-FWA solubility. Therefore, a D-FWA must be added to Hw-BKP under low conductivity conditions and at neutral or alkaline pH to optimize the D-FWA adsorption.

• 한국항행학회논문지
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• 제9권2호
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• pp.177-184
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• 2005

본 논문에서는 새로운 간섭 모델, 실제적인 HAPS 시나리오, HAPS 시스템과 FWA 시스템에 대한 안테나 패턴과 같은 파라미터들을 이용하여 HAPS 비행선에서 P-MP FWA 기지국과 P-MP FWA 단말국으로의 간섭 영향을 분석하였다. 분석 결과를 보게 되면, HAPS AS에서 P-MP FWA BS로의 간섭 경우에 두 시스템들 사이의 호환성은 섹터화된 BS 안테나를 이용함으로서 얻어질 수 있었다. 그러나 HAPS AS에서 P-MP FWA TS로의 경우에 동적 채널 할당과 같은 간섭 경감 기법을 이용한 이격 거리가 보장되지 않으면 두 시스템들은 동일한 대역에서 효과적으로 운용될 수 없었다.

• 펄프종이기술
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• 제47권1호
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• pp.52-58
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• 2015

White ledger usually includes white office paper, computer paper, and copy machine paper. Because these grades need high optical properties, fluorescent whitening agents (FWAs) are widely used in the papermaking process. FWAs are the most powerful and effective chemical used to obtain high CIE whiteness and ISO brightness in papers. The rising demand for white or ultra-white papers has increased the use of FWAs. However, FWAs used in white ledger can restrict its use, even though white ledger is widely used as a raw material in paperboard mills. Therefore, it is necessary to develop methods to control FWAs from white ledger to increase its use in paperboard mills. In this study, the behaviors of disulpho fluorescent whitening agent (D-FWA), tetrasulpo fluorescent whitening agent (T-FWA), and hexasulpho fluorescent whitening agent (H-FWA) during the recycling process were identified as a first step to remove FWAs from white ledger. We prepared four types of papers (dyed with D-FWA, T-FWA, and H-FWA), disintegrated these papers, and made handsheets. This recycling process was carried out three times in a laboratory. After each round of recycling, the hand-sheets' CIE whiteness and fluorescence index were measured, and the distribution of FWAs in the Z-direction was observed using CLSM images. FWA reductions in the model papers were calculated using fluorescence indices as a function of the number of recycling. FWAs in handsheets containing T-FWA and H-FWA decreased linearly as a function of the number of recycling, but D-FWA did not show a significant reduction in the fluorescence index after recycling. T-FWA and H-FWA showed similar distributions of D-FWA after recycling. Therefore, as much T-FWA and H-FWA as possible must be detached in the early processes of papermaking at paperboard mills.

• 한국전자파학회논문지
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• 제17권2호
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• pp.152-157
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• 2006

본 논문에서는 새로운 간섭 모델, 실제적인 HAPS(High Altitude Platform Station) 간섭 시나리오, HAPS 시스템과 FWA(Fixed Wireless Access) 시스템에 대한 안테나 패턴, 송신 전력 등과 같은 파라미터들을 이용하여 HAPS 시스템의 지상국(GS: Ground Station)으로부터 P-MP(Point-to-Multipoint) FWA 기지국(BS: Base Station)로의 간섭 및 HAPS 시스템의 GS로부터 FWA 단말국(TS: Terminal Station)으로의 간섭 영향에 대하여 분석하였다. 분석 결과를 보게 되면, HAPS GS로부터 P-MP FWA BS로의 간섭의 경우, 섹터화된 안테나를 사용하는 BS국이 nadir (HAPS 커버리지 중심)의 반대편을 바라보고 있을 때에 두 시스템은 효율적으로 운용될 수가 있다. 그러나 HAPS GS로부터 P-MP FWA TS로의 간섭의 경우에서는 충분한 이격거리가 보장되지 않거나, 간섭 경감 기법을 사용하지 않는다면 이 대역에서 두 시스템은 효율적인 스펙트럼 공유가 불가능하다.

• 펄프종이기술
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• 제43권2호
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• pp.9-15
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• 2011

Fluorescent whitening agent (FWA) is a widely used chemical in paper industry, but a systematic and scientific method on FWA analysis has not been established. We performed the basic researches on the fluorescence analysis of FWA. The fluorescence of FWA was investigated using a spectrofluorometer and a spectrophotometer. When FWA solution was analyzed using the spectrofluorometer, we found that the peak wavelength of the fluorescence emission was about 440 nm and that of the fluorescence excitation was about 370 nm irrespective of FWA types. Papers dyed with an internal FWA were prepared in a laboratory and the reflectance and the fluorescence index were measured using the spectrophotometer. It was confirmed that the optimum peak wavelength of the reflectance was 440 nm and the fluorescence index calculated from the CIE whiteness with and without UV light under a light source D65 was the best indicator to measure the fluorescence of FWAs exiting in papers.

• 인터넷정보학회논문지
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• 제22권2호
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• pp.19-27
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• 2021

Fireworks Algorithm (FWA) is a new heuristic swarm intelligent algorithm inspired by the natural phenomenon of the fireworks explosion. Though it is an effective algorithm for solving optimization problems, FWA has a slow convergence rate and less information sharing between individuals. In this paper, we improve the FWA. Firstly, explosion operator and explosion amplitude are analyzed in detail. The coefficient of explosion amplitude and explosion operator change dynamically with iteration to balance the exploitation and exploration. The convergence performance of FWA is improved. Secondly, differential evolution and commensal learning (CDE) significantly increase the information sharing between individuals, and the diversity of fireworks is enhanced. Comprehensive experiment and comparison with CDE, FWA, and VACUFWA for the 13 benchmark functions show that the improved algorithm was highly competitive.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.157-162
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• 2005

In this paper, we have analyzed the effects of interference from HAPS ground stations to P-MP FWA base station and to P-MP FWA terminal station using more detail parameters such as a new interference model, a realistic HAPS scenario, practical antenna patterns for both the HAPS system and FWA systems. The analysis results show that, in the case of interference from HAPS GSs into a P-MP BS, compatibility of the two systems can be obtained by using a sectored BS antenna with the boresight directed away from the nadir However, in the case of interference from HAPS GSs into a P-MP TS, the two systems cannot operate effectively in the same band unless the separation distance is guranteed and/or some form of interference mitigation technique is employed such as dynamic channel allocation.

• 펄프종이기술
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• 제43권4호
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• pp.76-81
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• 2011

This study was carried out in order to develop a speciality functional coated paper, which can be recognized under a ultraviolet lamp. The special fluorescent whitening agent (FWA) which absorbs ultraviolet light (397~410 nm) and emits it as yellowish light (570~500nm) was used. The special FWA was applied in a coating color in two ways: (1) direct application to a coating color as a FWA; (2) application on pigment surface, drying it and application it as a fluorescence whitening pigments (colored pigments). The effects of the special FWA on coating color properties were tested and the distribution of colored pigments in coated paper was evaluated under a ultraviolet lamp. The results showed that the colored pigments didn't affect on coating color properties. Experimental results showed the possibility of producing a security coated paper using the special FWA. To produce a speciality functional paper, it was found to be proper to apply the special FWA in the form of colored pigment.

• 한국염색가공학회지
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• 제12권3호
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• pp.192-198
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• 2000

Influence of the fluorescent whitening agent(FWA)'s adsorption on the whiteness of cotton and on the color change of the dyed fabrics was investigated by repeating wash cycles. Cotton 100% and cotton60/polyester40 blended fabrics were dyed pink, blue and yellow, and cyanuric chloride diamino stilbene(CC/DAS) and distyryl bisphenyl(DSBP) were used for the FWA with laundry detergents. Fabrics were washed at $20^\circ{C}$ with Terg-o-tometer. The FWA adsorption amount was measured by the absorption intensity for the pyridine-water extracted solution. The FWA adsorption increased on the cotton fabric with the wash cycles. Though adsorption of CC/DAS continuously increased up to the 20th cycle, that of DSBP increased sharply before the 10th cycle and reached an equilibrium. The whiteness of the fabrics dried in the shade was greater than that dried under the sunlight through window glass. The color change of dyed fabrics was increased by the number of wash cycles. Pink changed more greatly than blue, yellow or grey cloth. The color change(\Delta{E)}$ of dyed fabric washed repeatedly up to the 20th cycle with the detergent without FWA was less than 1. It is recommended to wash pale colored fabric with the detergent free of FWA.

• 펄프종이기술
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• 제48권3호
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• pp.5-13
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• 2016

This study investigated the effects of different factors on the migration of a fluorescent whitening agent (FWA) from paper treated with FWAs to non-fluorescent papers. FWA migration experiments were carried out in vertical and friction contacts between the papers dyed with FWAs and non-fluorescent papers. During the experiments, we identified the effects of the addition and types of FWAs, contact time, temperature, and relative humidity (RH) on FWA migration. The fluorescence indices of the non-fluorescent papers were measured before and after the migration experiments, and the Student's t test, a statistical tool, was utilized to compare results from different migration experiments. In vertical contact experiments, FWA migration to non-fluorescent paper was observed at $30^{\circ}C$ and 70% RH; this was attributed to the high moisture content of the paper. FWA migration did not occur significantly at $23^{\circ}C$ and 50% RH. In the friction contact experiments, FWA migrations were identified at both temperature conditions and RH percentages. The addition and types of FWAs did not increase the fluorescence index of non-fluorescent papers. Therefore, it was concluded that the moisture content of paper and the friction contact affected FWA migration from the papers containing internal and surface FWAs.