This study was carried out to investigate the effects of supercritical carbon dioxide (SC-CO2) extracts from sweet potatoes (SP) and watermelon (WM) on the oxidative stability of perilla seed oils (POs) over the existing ones. A comparison was done between the oxidative stability of perilla oil (PO) after the addition of 0.1% of SP, and WM extracts and PO without extract. The oxidative stability was measured based on the viscosity, acid value (AV), peroxide value (POV), antioxidant (DPPH) activity, p-anisidine value (p-AV), and fatty acid composition. The viscosities ranges were: PO without extract, from 53.99±0.99 to 74.38±1.61 cps, PO with SP extract, from 53.99±0.10 to 58.73±0.8 cps, and PO with WM extract, from 53.98±0.10 to 56.00±0.70 cps. While the PO containing the SC-CO2 extracts had significantly lower AV, POV, and p-AV, their antioxidant activity was approximately 10 times higher than that of the PO without extract. There were no significant differences in fatty acid composition between SC-CO2 extracts added groups and PO without extract (p<0.05). The findings of this study confirmed that the SC-CO2 extracts from sweet potatoes and watermelon enhanced the oxidative stability of perilla seed oils, and are potential natural antioxidants for use in the food industry.

In this study, binderless-WC, WC-6 wt%Co, WC-6wt% 1 and 2.5 B4C materials are fabricated by spark plasma sintering process (SPS process). Each fabricated WC material is almost completely dense, with a relative density up to 99.5 % after the simultaneous application of pressure of 60 MPa. The WC added Co and Co-B4C materials resulted in crystalline growth. The WC with HCP crystal structure has respective interfacial energy (basal facet direction: 1.07 ~ 1.34 J·m−2, prismatic direction: 1.43 ~ 3.02 J·m−2) that depends on the grain growth direction. It is confirmed that the continuous grain growth, biased by the basal facet, which has relatively low energy, is promoted at the WC/Co interface. As abnormal grain growth takes place, the grain size increases more than twice from 0.37 to 0.8 um. It is found through analysis that the hardness property also greatly decreases from about 2661.4 to 1721.4 kg/mm2, along with the grain growth.

Expensive PCBN or ceramic cutting tools are used for processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have the problem of breaking easily due to their high hardness but low fracture toughness. To solve these problems, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and research on various tool materials is being conducted. In this study, binderless-WC, WC-6 wt%Co, WC-6 wt%Co-1 wt% Mo2C, and WC-6 wt%Co-2.5 wt% Mo2C hard materials are densified using horizontal ball milled WC-Co, WC-Co-Mo2C powders, and spark plasma sintering process (SPS process). Each SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo2C, and WC-6 wt%Co- 2.5 wt% Mo2C hard materials are almost completely dense, with relative density of up to 99.5 % after the simultaneous application of pressure of 60 MPa and almost no significant change in grain size. The average grain sizes of WC for Binderless- WC, WC-6 wt%Co-1 wt% Mo2C, and WC-6 wt%Co-2.5 wt% Mo2C hard materials are about 0.37, 0.6, 0.54, and 0.43 μm, respectively. Mechanical properties, microstructure, and phase analysis of SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo2C, and WC-6 wt%Co-2.5 wt% Mo2C hard materials are investigated.

Bi2MoO6 (BMO) via the structure-directing role of CO(NH2)2 is successfully prepared via a facile solvothermal route. The structure, morphology, and photocatalytic performance of the nanoflake BMO are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence spectrum analysis (PL), UV-vis spectroscopy (UVvis) and electrochemical test. SEM images show that the size of nanoflake BMO is about 50 ~ 200 nm. PL and electrochemical analysis show that the nanoflake BMO has a lower recombination rate of photogenerated carriers than particle BMO. The photocatalytic degradation of tetracycline hydrochloride (TC) by nanoflake BMO under visible light is investigated. The results show that the nanoflake BMO-3 has the highest degradation efficiency under visible light, and the degradation efficiency reached 75 % within 120 min, attributed to the unique hierarchical structure, efficient carrier separation and sufficient free radicals to generate active center synergies. The photocatalytic reaction mechanism of TC degradation on the nanoflake BMO is proposed.

분자각인막(MIM)은 특정 분자의 결합자리를 갖고 있는 다공성 고분자 막이다. 비용매유도 상분리(NIPS)법을 사용하여 분자각인막의 지지체로 사용될 P(AN-co-MA) 비대칭막을 제조하고, 여기에 표면 각인법을 적용하여 광활성 이니퍼터 도입과 photo-grafting을 통해 라이소자임 분자각인막을 제조하였다. P(AN-co-MA) 비대칭막을 3-chloropropyltrimethoxysilane과 광활성 이니퍼터 dithiocarbamate로 개질하고, acrylamide 단량체, N,N'-methylenebisacrylamide 가교제, 라이소자임 주형분자 혼합액을 UV 조사 환경에서 혼성중합 시켜 MIM을 제조하였다. 제조된 MIM의 FT-IR과 FE-SEM 및 EDS 분석을 실시한 결과 P(AN-co-MA) 막은 비대칭 단면 구조이었고 표면에 이니퍼터 그룹이 잘 결합되어 있어 MIM이 성공적으로 제조되었다. 제조공정의 변수 조절을 통해 라이소자임의 흡착량이 비각인막(NIM)에 비해 13배 큰 값인 2.7 mg/g을 갖는 P(AN-co-MA) 기반 MIM이 제조되었으며, 막여과 실험을 통해 라이소자임에 대한 오발부민의 투과선택도를 측정한 결과 MIM은 라이소자임의 선택적 결합력이 우수하였다.

This study examined the effect of ultraviolet (UV) application on bacterial disinfection in a commercialized humidifier using ultrasonic wave (UW). To accurately examine disinfection kinetics in tap-water condition, tap-water was sterilized using a filter, and then inoculated with pure cultures of E. coli and P. putida with known viable counts. The disinfection kinetic characteristics were experimentally compared when UV alone, UW alone, and UW+UV together were applied in disinfecting the added bacteria in the commercialized humidifier. When UV alone was applied, bacterial disinfection kinetics followed a first-order decay reaction, and showed an approximately 10-time weaker disinfection compared to the typical UV disinfection in water treatment or wastewater treatment. When UW alone was applied, bacterial disinfection kinetics followed a second-order decay reaction with a low disinfection rate constant of 0.0002 min-1(CFU/mL)-1. When UV and UW were applied together, however and interestingly, the disinfection rate constant (0.0211 min-1(CFU/mL)-1) was approximately 100 times increased than that for the UW alone case. These results revealed that the co-use of UV and UW can provide synergistic effect on bacterial disinfection in a tap-water condition in household humidifiers.

Strontium lanthanum vanadate La1-xSrxVO3 (LSVO) is a promising anode material for electrochemical devices, especially for solid oxide fuel cells, thanks to its irregular electrical conductivity. However, the known synthesis methods are incapable of producing well-dispersed LSVO nanoparticles (NPs) with homogeneous size distribution, which partly impedes the applicability of the material. Thus, a new approach to synthesize LSVO NPs with such characteristics is of paramount importance. In the present work, we successfully prepare LSVO NPs with a high dispersion degree and homogeneous size distribution via a modified co-precipitation pathway, followed by hydrogen reduction at a temperature as low as 700 oC. The prepared LSVO NPs display uniform sizes in the range of 50 ~ 100 nm and do not contain any secondary phases, according to XRD analysis. The chemical mechanism of reactions that occur to form the LSVO is thoroughly highlighted. The work functions of NPs measured by the UPS analysis are in the 2.13 ~ 3.62 eV range, making the LSVO powders promising for use in thermionic devices. An explanation of the role of Sr substitution in work function values of LSVO is also proposed.

Increasing ambient carbon dioxide ( CO2) concentration from anthropogenic greenhouse gas emission has contributed to the growing rate of global land and ocean surface temperature. Various carbon capture and storage (CCS) technologies were established to mitigate this impending issue. CO2 adsorption is gaining prominence since unlike traditional chemical absorption, it does not require high energy usage for solvent regeneration and consumption of corrosive chemical solvent. In CO2 adsorption, activated carbons show high CO2 adsorption capacity given their well-developed porous structures. Numerous researches employed oil palm wastes as low-cost precursors. This paper provides a comprehensive assessment of research works available thus far in oil palm-derived activated carbon (OPdAC) for CO2 adsorption application. First, we present the desired OPdAC characteristics and its precursors in terms of their chemical properties, elemental, and proximate compositions. This is followed by an overview of various activation methodologies and surface modification methods to attain the desired characteristics for CO2 adsorption. Then the focus turned to present available OPdAC CO2 adsorption performance and how it is affected by its physical and chemical characteristics. Based on these, we identify the challenges and the potential development in different aspects such as precursor selection, process development, and optimization of parameter. A pilot scale production cost analysis is also presented to compare various activation and surface modification methods, so that the appropriate method can be selected for CO2 adsorption.