Carbon fibers (CFs) are considered promising composite materials for various applications. However, the high cost of CFs (as much as $26 per kg) limits their practical use in the automobile and energy industries. In this study, we developed a continuous stabilization process for manufacturing low-cost CFs. We employed a textile-grade polyacrylonitrile (PAN) fiber as a low-cost precursor and UV irradiation technique to shorten the thermal stabilization time. We confirmed that UV irradiation on the textile-grade PAN fibers could lower the initial thermal stabilization temperature and also lead to a higher reaction. These resulted in a shorter overall stabilization time and enhancement of the tensile properties of textilegrade PAN-based CFs. Our study found that only 70 min of stabilization time with UV irradiation was required to prepare textile-grade PAN-based low-cost CFs with a tensile strength of 2.37 ± 0.22GPa and tensile modulus of 249 ± 5 GPa.

Effects of growth variables and post-growth annealing on the optical, structural and electrical properties of magnetron-sputtered Ga0.04Mg0.10Zn0.86O films are characterized in detail. It is observed that films grown from pure oxygen plasma showed high resistivity, ~102 Ω·cm, whereas films grown in Ar plasma showed much lower resistivity, 2.0 × 10− 2 ~ 1.0 × 10−1 Ω·cm. Post-growth annealing significantly improved the electrical resistivity, to 4.3 ~ 9.0 × 10−3 Ω·cm for the vacuum annealed samples and to 1.3 ~ 3.0 × 10−3 Ω·cm for the films annealed in Zn vapor. It is proposed that these phenomena may be attributed to the improved crystalline quality and to changes in the defect chemistry. It is suggested that growth within oxygen environments leads to suppression of oxygen vacancy (Vo) donors and formation of Zn vacancy (VZn) acceptors, resulting in highly resistive films. After annealing treatment, the activation of Ga donors is enhanced, Vo donors are annihilated, and crystalline quality is improved, increasing the electron mobility and the concentration. After annealing in Zn vapor, Zn interstitial donors are introduced, further increasing the electron concentration.

This study was conducted to evaluate the degradation and mineralization of PPCPs (Pharmaceuticals and Personal Care Products) using a CBD(Collimated Beam Device) of UV/H2O2 advanced oxidation process. The decomposition rate of each substance was regarded as the first reaction rate to the ultraviolet irradiation dose. The decomposition rate constants for PPCPs were determined by the concentration of hydrogen peroxide and ultraviolet irradiation intensity. If the decomposition rate constant is large, the PPCPs concentration decreases rapidly. According to the decomposition rate constant, chlortetracycline and sulfamethoxazole are expected to be sufficiently removed by UV irradiation only without the addition of hydrogen peroxide. In the case of carbamazepine, however, very high UV dose was required in the absence of hydrogen peroxide. Other PPCPs required an appropriate concentration of hydrogen peroxide and ultraviolet irradiation intensity. The UV dose required to remove 90% of each PPCPs using the degradation rate constant can be calculated according to the concentration of hydrogen peroxide in each sample. Using this reaction rate, the optimum UV dose and hydrogen peroxide concentration for achieving the target removal rate can be obtained by the target PPCPs and water properties. It can be a necessary data to establish design and operating conditions such as UV lamp type, quantity and hydrogen peroxide concentration depending on the residence time for the most economical operation.

The UV/chlorine process is a UV-based advanced oxidation process for removing various organic pollutants in water. The process is becoming increasingly popular because of its effectiveness in practice. It is important to the safe and efficient operation of a UV/chlorine process that the optimal operating conditions for both target removal objective and saving energy are determined. Treatment efficiency of target compounds in UV/chlorine process was mainly affected by pH and scavenging factor. In this study, kinetic based mathematical model considering water characteristics and electrical energy dose calculations model was developed to predict of treatment efficiency and optimal operating conditions. The model equation was validated for the UV/chlorine process at the laboratory scale and in pilot tests at water treatment plants.

The purpose of this study is to confirm the removal effect of odorous gas through the multi process. The combination of Scrubber, UV and Adsorption was analyzed using the odor gas of reservoir. Analysis was carried out for six times in total and collection was made once per each process. Sampling was performed in the afternoon during August (1:00 pm~4:00 pm). Multi process has been designed to facilitates the accessories exchange. The advantage is that it facilitates the replacement of the activated carbon and it is convenient to change the type of chemical according to the type of pollution materials. As a result, for odor gas removal efficiency, ammonia 91.8%, trimethylamine 72.0%, hydrogen sulfide 99.9%, methyl mercaptan 99.9% were removed respectively. Removal efficiency of the process is the scrubber (alkali), activated carbon adsorption, scrubber (acid) and UV procedure from the highest order. Further studies on the operating method and efficiency of multi process by the change of wind speed and chemical are recommended.

1-D ZnO nanowires have been attractive for their peculiar properties and easy growth at relatively low temperature. The length, diameter, and density of ZnO nanowires were determined by the several synthetic parameters, such as PEI concentration, growth time, temperature, and zinc salt concentration. The ZnO nanowires were grown on the<001> oriented seed layer using the hydrothermal process with zinc nitrate and HMTA (hexamethylenetetramine) and their structure and optical properties were characterized. The morphology, length and diameter of the nanowires were strongly affected by the relative and/or absolute concentration of Zn2+ and OH-1 and the hydrothermal temperature. When the concentrations of the zinc nitrate HMTA were the same as 0.015 M, the length and diameter of the nanowires were 1.97μm and 0.07μm, respectively, and the aspect ratio was 28.1 with the preferred orientation along the<001> direction. XRD and TEM results showed a high crystallinity of the ZnO nanowires. Optical measurement revealed that ZnO nanowires emitted intensive stimulated UV at 376 nm without showing visible emission related to oxygen defects.

This paper presented experimental results for circulation type UV-TiO₂ photocatalytic oxidation process. We have developed UV-TiO₂ photocatalytic oxidation process with activated carbon to control odor and VOCs in indoor and industrial applications. In this study, common indoor air pollutants, namely ammonia, formaldehyde, hydrogen disulfide, toluene were selected to investigate their efficiencies for UV-TiO₂ photocatalytic oxidation. In high concentration test, the decomposition efficiency was high in order as ammonia, toluene, formaldehyde, hydrogen disulfide. Three type of individual processes are tested for ability to increase decomposition efficiency. UV-TiO₂ photocatalytic oxidation combined process with activated carbon was excellent among the three type processes without reference to gas species. It was considered that this circulation type process will overcome short retention time for treatment for UV-TiO₂ photocatalytic oxidation. It will promise that this circulation type UV-TiO₂ photocatalytic oxidation combined process can apply indoor and industrial applications to remove odor and VOCs quickly.

The International Maritime Organization (IMO) ballast water management agreement (International Convention for the Control and Management of Ship's Ballast Water and Sediments) came into force on September 8, 2017. This study evaluated the disinfection performance of electrolysis, UV treatment, and electrolysis + UV combined, to improve the treatment of zooplankton (size ≥ 50 μm), which is expected to strengthen the standards for biodegradation efficiency. Among the methods used, the disinfection time leading to 100% death was in the order: electrolysis > electrolysis + UV > UV process. For the same level of disinfection performance, the amount of electricity required for the electrolysis, UV, and electrolysis + UV processes were 1,300 W.s, 8,400 W.S, and 4,500 W.s, respectively. The combination of electrolysis + UV process for inactivation of zooplankton in ballast water did not show a synergic effect owing to the slow disinfection time and high power consumption.

Aeration with low energy micro-bubble generation and UV/H2O2 processes was introduced to verify the possibility of oxidation treatment for acid mine drainage. During 10 hours of aeration with micro-bubbles, Fe and As concentrations were decreased to 18.1 and 61.8%, respectively, while Cu, Cd, Al were kept at influent concentrations. Other heavy metals such as Mn, Cr, Pb, Zn, and Ni concentrations fluctuated due to the repetition of oxidation and release. Twenty days of aeration indicated the oxidation possibility for Cu, Cd, and Al. With the employment of UV/H2O2 processes, more than 77% of Cu and Fe removed, whereas slightly more than 30% of Cd and Al removed.

The experimental design and response surface methodology (RSM) have been applied to the investigation of the electro-UV complex process for the disinfection of E. coli in the water. The disinfection reactions of electro-UV process were mathematically described as a function of parameters power (X1), NaCl dosage (X2), initial pH (X3) and disinfection time (X4) being modeled by use of the Box-Behnken technique. The application of RSM using the Box-Behnken technique yielded the following regression equation, which is an empirical relationship between the residual E. coli number and test variables in actual variables: Ln (CFU) = 23.57 - 0.87․power - 1.87․NaCl dosage - 2.13․pH - 2.84․time - 0.09․powe r․time - 0.07․NaCl dosage․pH + 0.14․pH․time + 0.03․power 2 + 0.47․NaCl dosage 2 + 0.20․pH 2 + 0.33․time 2 . The model predictions agreed well with the experimentally observed result (R 2 = 0.9987). Graphical response surface and contour plots were used to locate the optimum point. The estimated ridge of maximum response and optimal conditions for the E. coli disinfection using canonical analysis was Ln 1.06 CFU (power, 15.40 W; NaCl dosage, 1.95 g/L, pH, 5.94 and time, 4.67 min). To confirm this optimum condition, the obtained number of the residual E. coli after three additional experiments were Ln 1.05, 1.10 and Ln 1.12. These values were within range of 0.62 (95% PI low)～1.50 (95% PI high), which indicated that conforming the reproducibility of the model.

Enhancement effect of ultrasonification process on UV-protection and skin-whitening activities using Centella asiatica L. Urban extract was investigated. Cytotoxicity of the extracts measured on human skin fibroblast cells, CCD-986sk, and then, ultrasonification associated extracts showed 5~9% lower cytotoxicity then normal crude extracts on 1.0 mg/ml of highest sample concentration. The associated extrats showed highest inhibition activity of hyaluronidase on 1.0 mg/ml of concentration as 54.2%. Also, the associated extract reduced expression of MMP-1 on UV-irradiated CCD-986sk cells down to 100.2% from 136.1%, and revealed high inhibitory potency on tyrosinase as 74.6% by adding 1.0 mg/ml of concentration. Ultrasonification associated extract showed strong inhibition effect of melanin production on Clone M-3 cells as 84.2% by adding 1.0 mg/ml of concentration. From the preliminary observations, we considered that the extracts from C. asiatica could be potent natural materials for skin-whitening and anti-aging agent, and could enhance the activities by ultrasonification process.

The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with TiO₂ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of TiO₂ photoelectrode were used. Thermal oxidation electrode (Th-TiO₂) was made by oxidation of titanium metal sheet; sol-gel electrode (SG-TiO₂) and powder electrode (P-TiO₂) were made by coating and then heating a layer of titania sol-gel and slurry TiO₂ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelectrodes and DSA electrodes is: Ru/Ti > Ti > SG-TiO₂ > Th-TiO₂. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. Na₂SO₄ and NaCl showed different decolirization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

본 연구에서는 초고압 추출 공정의 활성 증진 효과를 알아보기 위해 당귀의 자외선 차단 효과 및 피부 미백활성 실험을 실시하였다. 인간의 섬유아세포인 CCD-986sk를 이용한 세포독성 실험에서 1.0mg/ml 농도의 시료 첨가를 통해 초음파 병행 60℃ 추출물이 21.27%로 가장 낮은 세포독성을 나타내었으며, 15분간 초고압 처리한 60℃초음파 병행 추출물이 23.49%로 가장 높은 세포독성을 나타내었다. UVA 처리에 따른 MMP-1 발현 저해 효과 측정에서 1.0mg/ml 첨가를 통해 15분간 초고압 처리한 60℃ 초음파 추출물이 UV를 조사하지 않은 대조군과 비교하여 122.2%를 나타내며 양성대조군인 ascorbic acid의 121.3%와 근사한 수치의 발현 억제 효과를나타내었다. 그 외 다른 시료들도 134.5% 이하로 발현하며 높은 저해율을 나타냄에 따라 당귀가 UVA에 대한 MMP-1 발현 저해 효과가 있음을 나타내었다. Tyrosinase 억제효과에서는 양성대조군인 ascorbic acid가 1.0mg/ml의 농도에서 70.8%로 가장 높은 저해율을 나타내었다. 당귀 시료 중에서는 초고압을 15분간 처리한 60℃ 초음파 추출물이 ascorbic acid에 근사한 수치인 69.4%로 가장 높은 저해율을 나타내었고, 그외의 시료들도 모두 55% 이상의 높은 저해율을 나타내었다. 시료 첨가를 통한 Clone M-3 세포주의 melanin 생성 억제실험에서 1.0mg/ml 농도 첨가를 통해 15분간 초고압 처리한 60℃ 초음파 추출물이 82.4%를 나타내어 양성대조군인 ascorbic acid에 비해 더 높은 활성을 나타내었다. 이상의 결과를 통하여 당귀가 자외선 차단 및 피부 미백 관련 향장 소재로의 활용 가능성이 있으며, 초고압 처리를 통해 향장활성의 증가가 가능함을 확인하였다.

This study introduces a method to eliminate formaldehyde and benzene, toluene from indoor air by means of a photocatalytic oxidation reaction. In the method introduced, for the good performance of the reaction, the effect and interactions of the TiO2 catalyst and ultraviolet in photocatalytic degradation on the reaction area, dosages of catalysts, humidity and light should be precisely examined and controled. Experiments has been carried out under various intensities of UV light and initial concentrations of formaldehyde, benzene and toluene to investigate the removal efficiency of the pollutants. Reactors in the experiments consist of an annular type Pyrex glass flow reactor and an 11W germicidal lamp. Results of the experiments showed reduction of formaldehyde, benzene and toluene in ultraviolet /TiO2/ activated carbon processes (photooxidation-photocatalytic oxidation-adsorption processes), from 98% to 90%, from 98% to 93% and from 99% to 97% respectively. Form the results we can get a conclusion that a ultraviolet/Tio2/activated carbon system used in the method introduced is a powerful one for th treatment of formaldehyde, benzene and toluene of indoor spaces.

The objective of this study is to delineate removal efficiency of the MTBE in solution by TiO2 photocatalytic degradation as a function of the following different experimental conditions : Initial concentration of MTBE, air flow rate in solution, H2O2 dosage and pH of the solution. hotodegradation rate was increased with decreasing initial concentration of MTBE. The removal efficiency was 82% after 180 min in the case of MTBE concentration of 100 mg/L but 100% after 180 min in the case of 20 mg/L. Removal efficiency was increased with increasing pH, H2O2 dosage and air flow rate in solution.

In this study, the decomposition of gas-phase TCE, Benzene and Toluene, in air streams by direct UV Photolysis and UV/TiO2 process was studied. For direct UV Photolysis, by regressing with computer calculation to the experimental results the value of reaction rate constant k of TCE, Toluene and Benzene in this work were determined to be 0.00392s-1, 0.00230s-1 and 0.00126s-1, respectively. And the adsorption constant K of TCE, Toluene and Benzene in this work were determined to be 0.0519mol-1 ,0.0313mol-1 and 0.0084mol-1, respectively. For UV/TiO2 system by regressing with computer calculation to the experimental results the value of reaction rate constant k of TCE, Toluene, and Benzene in this work were determined to be 5.74g/ℓ․min, 3.85g/ℓ․min, and 1.18g/ℓ․min, respectively. And the catalyst adsorption constant K of TCE, Toluene, and Benzene in this work were determined to be 0.0005m3/mg, 0.0043m3/mg and 0.0048m3/mg, respectively.