• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.177-183
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• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• Resources Recycling
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• v.26 no.2
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• pp.11-17
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• 2017

Many problems are occurred by using industrial by-product and municipal solid waste in the cement manufacturing process. The main components of chlorine by-pass dust generated by the use of the wastes are $K^+$, $Cl^-$, and a slight amount of heavy metals is also contained. In terms of waste recycling, it is necessary to eliminate the heavy metals. Therefore, in this study, the experiments for the removal of heavy metals from KCl which was produced by chlorine by-pass dust were conducted. In order to find optimum conditions for the removal of heavy metals, we have controlled the amount of water and precipitator. The type and concentration of heavy metals in KCl were analyzed. The concentration of heavy metals decreased as amount of precipitator increased. The heavy metals such as Pb, Cd, and As were not detected in dust A and B, when the mixing ratios between dust A(B) and water were controlled to be 1:2 (1:2, 1:3.5) with the addition of 3% precipitator (NaOCl).

• Science of Emotion and Sensibility
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• v.19 no.2
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• pp.35-42
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• 2016

Electrospinning is a simple and effective process for producing nanofiber with diameter range from nanometers to micrometers which have high specific surface area. Hence, medicated nanofibers can be readily fabricated using a solution containing a mixture of a plant-extracts and a polymer. It has proved that Juniperus Chinensis can be effectively used for the prevention of UV and SLS-induced advers skin reaction such as radical production, inflammation and skin cell damage. It also found that Juniperus Chinensis has efficient ingredient of antifungal activity and house dust mite repellent effect. The fabrication of PVA nanofibers containing Juniperus Chinensis extracts by electrospinning has been studied. PVA/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis concentrations (0.25, 0.5, 1.5 wt. %). The parameters of electrospinning including polymer contents, voltage and tip-to-collector distance (TCD) were optimized for fabrication process. The study show that 12 wt. % PVA, 10kV applied voltage and TCD 10~20 cm are the best condition to obtain uniform PVA/Juniperus Chinensis extracts composite nanofibers. Morphologies of the electrospun composite nanofiber were observed by using a field emission scanning electron microscope. It has been found that the average diameters of fibers increased by the adding of Juniperus Chinensis extracts. As the results, PVA/Juniperus Chinensis extracts composite nanofibers having a diameter in the range from 310~360 nm were successfully prepared via an electrospinning.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.04a
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• pp.48-48
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• 2000

효율적인 wet-end시스템의 적용으로 중성 초지시스템의 이점을 최대한 구현하고 이에 따른 초지계의 안정성 및 원가절감 등을 얻기 위해서는 중성 초지 시스템에서 사용되는 사 이즈제 및 사이징 공정에 대한 연구가 매우 중요하다. 현재 중성 사이즈제로는 AKD와 A ASA가 가장 널리 사용되고 있는데, 유럽에서는 주로 AKD가 쓰이고 있으며, 미국에서는 A ASA가 50%정도 사용되고 있다 .. AKD에 비해서 ASA는 사이즈도의 발현이 매우 빨라 사이 즈 프레스에서 사이즈도가 발현되므로 사이즈 프레스에서의 픽엽 조절 및 지절감소에 유리 한 장점을 가지고 있다. 하지만 ASA는 AKD에 비해 반웅성 높아 습부에서의 가수분해되어 초지 조업성을 악화시키는 문제점을 지니고 있다. 이러한 문제를 극복하기 위해서는 ASA 유화액의 정착성을 개선시키기 위한 연구가 시급히 요청되고 있으며 여기에는 ASA의 유화 에 사용되는 양성전분의 최적화가 가장 핵심적인 기술로 평가된다. 현재 ASA용 유화제로는 양성전분이 가장 많이 사용되고 있다. ASA 에멀션 제조에 있 어서 양성전분의 역할은 음전하를 가지고 있는 ASA 입자에 홉착되여 양전하를 부여함으로 써 콜로이드 업자의 안정성을 부여할 뿐만 아니라 섬유와의 정전기적 인력을 유도하여 정착 을 증진시키는 효과를 나타낸다. ASA 유화용으로 쓰이는 양성전분 중에서는 감자전분이 가 장 효과적인 것으로 알려져 있으며 옥수수나 타피오카 둥도 쓰이고 있다. 그러나 국내의 경 우 감자전분은 옥수수전분보다 가격이 비싸다는 단점이 있으므로 저렴한 옥수수 전분을 이 용하여 ASA 유화용 변성전분의 개발이 국내 제지산업의 경쟁력 강화를 위해 시급히 요망 되고 있다. 본 연구의 목표는 옥수수 전분을 이용한 ASA용 유화안정제를 개발하고 그 효과를 극대 화시킬 수 있는 적용기술을 확립하는데 있다. 옥수수전분을 이용한 ASA 유화용 변성전분은 외국에서 소개된 바가 있기는 하지만 사이즈도 발현이 감자전분의 절반 수준으로 효과적이 지 못한 것이 문제점으로 지적된 바 있다. A ASA 유화용 전분으로는 감자전분과 옥수수전분으로 제조된 외국산 기존 제품과 본 연 구를 통해 개발된 옥수수 전분을 이용하였다. 먼저 실험실적으로 최적의 ASA 에멸션의 유 화가 가능하도록 유화조건을 설정하여 유화액의 입도가 1µm 정도가 되도록 하였다. 이들 A ASA 사이즈제를 Hw. Sw-BKP로 조성된 지료에 투입하여 수초한 후 Hercules 사이즈도 측정기를 이용하여 수초지의 사이즈도를 측정하였다. 또 사이정 효과를 극대화시키기 위한 방안을 모색하기 위해 ASA 에말션의 입도, 제타전위, 탁도 등의 평가를 병행 실시하였다. 실험 결과 기존의 방법으로 유화한 경우 수입감자양성전분이 가장 높은 사이즈도를 보였 다. 그러나, 적절한 전분변성법과 유화조건을 개선함으로써 옥수수전분을 이용하여 수입 감 자전분이나 수입 옥수수전분보다 더 우수한 ASA 사이정 효과를 나타내는 양성전분이 개발 될 수 있음을 확인하였다.

• Clean Technology
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• v.25 no.3
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• pp.189-197
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• 2019

In this study an optimization of the preparation conditions of activated carbon with a ternary metal ion material to treat $H_2S$, which is classified as a representative odor substance, was carried out. For a metal ion material for enhancing the adsorption performance of hydrogen sulfide, performance enhancement was confirmed by combining Li and Fe or a ternary combination (K, Li, Fe) based on KI, which is a substance promoting hydrogen sulfide adsorption performance. Also, it was determined by XRD analysis that the reaction of each active substance with $H_2S$ was because of binding. The adsorption performance increased more than 3 times with heat treatment of the adsorbent with nitrogen compared with heat treatment with air. The maximum adsorption constant ($q_m$) value of the optimum adsorbent was 97.07, which is 6 times higher than that of the existing K-based impregnated activated carbon. It was confirmed that the objective adsorption amount ($0.3g\;g^{-1}$) was secured by an equilibrium between the mass transfer rate and adsorption rate. From the results, it was confirmed that the performance improvement was noticeable even when activated carbon with a reagent grade activated carbon particle size was modified. It was confirmed that the adsorption performance exists at high relative humidity levels of 60 and 100%, and the optimized preparation can be applied to a wet process such as a scrubber downstream.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.19-26
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• 2021

The lattice structure is attracting attention from industry because of its excellent strength and stiffness, ultra-lightweight, and energy absorption capability. Despite these advantages, widespread commercialization is limited by the difficult manufacturing processes for complex shapes. Additive manufacturing is attracting attention as an optimal technology for manufacturing lattice structures as a technology capable of fabricating complex geometric shapes. In this study, a unit cell was formed using a three-dimensional coordinate method. The relative density relational equation according to the boundary box size and strut radius of the unit cell was derived. Simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) with a controlled relative density were designed using modeling software. The accuracy of the equations for calculating the relative density proposed in this study secured 98.3%, 98.6%, and 96.2% reliability in SC, BCC, and FCC, respectively. A simulation of the lattice structure revealed an increase in compressive yield load with increasing relative density under the same cell arrangement condition. The compressive yield load decreased in the order of SC, BCC, and FCC under the same arrangement conditions. Finally, structural optimization for the compressive load of a 20 mm × 20 mm × 20 mm structure was possible by configuring the SC unit cells in a 3 × 3 × 3 array.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.222-229
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• 2024

The use of low-toxic, hypoallergenic, and environmentally friendly natural pigments has increased. With growing interest in health, research on natural extracts containing beneficial substances for the human body is actively underway. In this study, natural pigments were extracted from sprout barley using a solvent extraction method and CCD-RSM was used to optimize the extraction process. The experiment's independent variables included extraction temperature, alcohol/ultra-pure volume ratio, and extraction time. The response variables were set to achieve a target chromaticity (L = 45, a = -35, b = 45), and to maximize DPPH radical scavenging activity evaluating the antioxidant capacity. The statistical significance of the main effect, interaction effect, and effect on the response value was evaluated and analyzed through the F and P values for the regression equation variables calculated using RSM optimization. Additionally, the reliability of the experiment was also confirmed through the P values of the probability plot graph. The extraction conditions for optimizing the four reaction values are 76.1 vol.% alcohol/ultra pure water volume ratio, an extraction temperature of 52.9 ℃ , and an extraction time of 49.6 min. Under these conditions, the theoretical values of the reaction values are L = 45.4, a = -36.8, and b = 45.0 DPPH radical scavenging activity = 30.9%. When the actual experiment was conducted under these optimal extraction conditions and analyzed, the measured values were L = 46.2, a = -36.1, and b = 48.2, and antioxidant capacity = 31.1% with an average error rate of 2.9%.

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.155-161
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• 2007

In this study, the reactivity of a $SnO_2-ZrO_2$(Sn/Zr = 2/1) catalyst for $SO_2$ reduction by CO was investigated in order to optimize the various reaction conditions such as temperature, gas hourly space velocity (GHSV), and [CO]/[$SO_2$] molar ratio. The reaction temperature in the range of $300{\sim}550^{\circ}C$, space velocity in the range of $5000{\sim}30000cm^3/[g_{-cat}{\cdot}h]$ and [CO]/[$SO_2$] molar ratio in the range of 1.0~4.0 were employed. The optimum temperature, GHSV, and [CO]/[$SO_2$] molar ratio were determined to be $325^{\circ}C$, $10000cm^3/[g_{-cat}{\cdot}h]$, and 2.0, respectively; under these conditions, $SO_2$ conversion was over 99% and sulfur selectivity was over 95%. In addition, the effect of $H_2O$ content on the $SO_2$ reduction by CO was also investigated. As the $H_2O$ content increased from 2 vol% up to 6 vol%, the reactivity and sulfur selectivity decreased. In case of 2 vol% $H_2O$ content, the reaction temperature and [CO]/[$SO_2$] molar ratio were varied in the range of $300{\sim}400^{\circ}C$ and 1.0~3.0. The optimum temperature and [CO]/[$SO_2$] molar ratio were $340^{\circ}C$ and 2.0, respectively under which $SO_2$ conversion and sulfur selectivity were about 90% and 87%, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.955-960
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• 2008

We investigated and estimated at the characteristics of decomposition and mineralization of benomyl using a design of experiment(DOE) based on the general factorial design in an E-beam process, and also the main factors(variables) with benomyl concentration(X$_1$) and E-beam irradiation(X$_2$) which consisted of 5 levels in each factor was set up to estimate the prediction model and the optimization conditions. At frist, the benomyl in all treatment combinations except 17 and 18 trials was almost degraded and the difference in the decomposition of benomyl in the 3 blocks was not significant(p > 0.05, one-way ANOVA). However, the % of benomyl mineralization was 46%(block 1), 36.7%(block 2) and 22%(block 3) and showed the significant difference of the % that between each block(p < 0.05). The linear regression equations of benomyl mineralization in each block were also estimated as followed; block 1(Y$_1$ = 0.024X$_1$ + 34.1(R$^2$ = 0.929)), block 2(Y$_2$ = 0.026X$_2$ + 23.1(R$^2$ = 0.976)) and block 3(Y$_3$ = 0.034X$_3$ + 6.2(R$^2$ = 0.98)). The normality of benomyl mineralization obtained from Anderson-Darling test in all treatment conditions was satisfied(p > 0.05). The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were Y = 39.96 - 9.36X$_1$ + 0.03X$_2$ - 10.67X$_1{^2}$ - 0.001X$_2{^2}$ + 0.011X$_1$X$_2$(R$^2$ = 96.3%, Adjusted R$^2$ = 94.8%) and 57.3% at 0.55 mg/L and 950 Gy, respectively. A Microtox test using V. fischeri showed that the toxicity, expressed as the inhibition(%), was reduced almost completely after an E-beam irradiation, whereas the inhibition(%) for 0.5 mg/L, 1 mg/L and 1.5 mg/L was 10.25%, 20.14% and 26.2% in the initial reactions in the absence of an E-beam illumination.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.917-925
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• 2006

The aim of our research was to apply experimental design methodology in the optimization of photocatalytic degradation of azo dye(Reactive orange 16). The reactions were mathematically described as a function of parameters amount of $TiO_2(x_1)$, and dye concentration($x_2$) being modeled by the use of the Box-Behnken method. The results show that the responses of color removal(%)($Y_1$) in photocatalysis of dyes were significantly affected by the synergistic effect of linear term of $TiO_2(x_1)$ and dye concentration($x_2$). Significant factors and synergistic effects for the $COD_{Cr}$, removal(%)($Y_2$) were the linear term of $TiO_2(x_1)$ and dye concentration($x_2$). However, the quadratic term of $TiO_2(x_1^2)$ and dye concentration($x_2^2$) had an antagonistic effect on $Y_1$ and $Y_2$ responses. Canonical analysis indicates that the stationary point was a saddle point for $Y_1$ and $Y_2$, respectively. The estimated ridge of maximum responses and optimal conditions for $Y_1:(X_1,\;X_2)$=(1.11 g/L, 51.2 mg/L) and $Y_2:(X_1,\;X_2)$=(1.42 g/L, 72.83 mg/L) using canonical analysis was 93% and 73%, respectively.