본 연구에서는 유기계 산화 방지제인 가려진 페놀이 그래프팅된 산화 그래핀(hindered phenol-grafted graphene oxide, HP-GO)을 합성하였고, 이를 도입한 나피온(Nafion) 기반의 복합 막을 제조하여 고분자 전해질 막 연료전지에 응용하 였다. HP-GO는 3,5-디-tert-뷰틸-4-히드록시페닐프로피오닐 클로라이드에 존재하는 염화 카보닐기(carbonyl chloride)와 GO에 존재하는 히드록시간의 치환 반응을 통해 합성되었으며, 합성된 HP-GO를 고분자 기지체 대비 0.01~0.5 wt%까지 포함하는 복합 막을 제조하여 순수 Nafion과의 물성 차이를 비교하였다. 특정 함량의 HP-GO가 첨가된 복합 막은 순수 Nafion에 비해 우수한 인장강도와 수분 흡수율 및 치수안정성을 나타내었다. 특히 HP-GO의 산화 방지 특성으로 인해 HP-GO가 첨가된 복 합 막은 장시간의 펜톤 평가(Fenton’s test) 이후 순수 Nafion 대비 높은 산화 안정성을 나타내었다. 또한 HP-GO에 의한 향상 된 수분 흡수율에 의해 복합 막은 전 습도 구간에서 순수 Nafion 대비 우수한 수소 이온 전도도를 나타내었다.

Agriculture plays a critical role in Uganda’s economy, contributing to 24% of the gross domestic product (GDP) and serving as the primary source of livelihood for a large portion of the population. Organic horticulture presents a promising pathway for sustainable development, offering economic opportunities through access to niche markets both locally and internationally. However, effective management for pests and diseases remains a major challenge in organic horticulture. This review addresses pest and disease issues affecting non-traditional export crops in Uganda, such as pepper, bitter gourd, and aubergine. Additionally, it provides an overview of botanical pesticides currently used in Uganda, along with approved organic fungicides (e.g., lime sulfur, copper) and insecticides (e.g., paraffinic oils, pyrethrum). This review explores physical and chemical properties, target pests, benefits, drawbacks, and active ingredients of these substances. The ultimate aim is to offer Ugandan farmers expanded options for managing pests and diseases in organic horticulture.

Volatile organic compounds (VOCs) can adversely affect human and plant health by generating secondary pollutants such as ozone and fine particulate matter, through photochemical reactions, necessitating systematic management. This study investigated the distribution characteristics of gaseous VOCs in ambient air, with a focus on interpreting data from a photochemical pollution perspective. This paper analyzed the presence and concentration distribution of VOCs in industrial areas, identifying toluene, m-xylene, p-xylene, and n-octane as the most frequently detected components. Particularly, toluene was found to significantly contribute to the formation of ozone and fine particulate matter, highlighting the need for stricter regulation of this compound. Although n-octane and styrene were present in relatively low concentrations overall, their significant contributions to ozone generation and secondary organic aerosol formation, respectively, emphasize their importance in air pollution management.

본 연구는 폴리케톤(PK) 지지체를 이용한 유기용매 역삼투(OSRO) 분리막 제조를 목적으로 하였다. 비용매 유도 상분리 방법(NIPS)을 통해 PK 지지체를 제작하였고, PK 지지체 위에 polyamide layer를 계면 중합하여 thin-film composite (TFC) 형태로 OSRO 분리막을 완성하였다. 이후 OSRO 분리막의 표면과 단면 구조 및 표면의 화학적 구조를 분석하였고 수 투과도와 염 제거율은 각각 약 1.28 LMH/bar와 99.0%의 결과를 얻었다. 또한 OSRO 분리막의 polyamide layer는 유기용매 침지 1일 동안 매우 안정적이었고, 단일 유기용매 투과도 경향성은 유기용매 나노여과(OSN) 분리막의 투과도 모델과 일치하 였다. OSRO 분리막의 MWCO는 MeOH 상에서 240 g/mol이었다. OSRO 분리막의 MeOH-toluene 혼합용액에 대한 투과도 와 separation factor는 상용 OSN 분리막보다 각각 200%와 60%의 높은 결과를 얻었다.

In this study, two alignment methods were used to create a Fringe-Field Switching (FFS) mode liquid crystal device using an organic thin film (polyimide: PI) as an alignment layer. In addition, the electro-optical (EO) characteristics of the liquid crystal device manufactured in this way were investigated to evaluate the feasibility of mass production application of the technology. In general, the photo-alignment method using unpolarized ultraviolet rays can obtain a relatively low pretilt angle, so a liquid crystal device in FFS mode, which is a driving mode of the liquid crystal device that reflects the characteristics of liquid crystal alignment, was manufactured, and the liquid crystal has a high reactivity with the alignment film. Considering this, nematic liquid crystal (NLC) was used. In addition, in order to improve the misalignment, it was observed whether more stable orientation occurred by irradiating ultraviolet rays for an additional 1 to 3 hours in the aligned state. As a result of the experiment, it was found that NLC alignment occurs through a photodecomposition reaction caused by unpolarized UV irradiation oblique to the PI surface. In addition to the existing orientation method, UV irradiation was used to achieve a more stable orientation state and stable V-T curve and response characteristics. With liquid crystal alignment completed, more stable orientation characteristics and EO characteristics at the mass production level were obtained through additional UV irradiation for 3 hours. This method can further stabilize the orientation stability caused by existing UV irradiation through an additional process.

This study evaluated the importance of assessing personal exposure to volatile organic compounds (VOCs) by monitoring indoor, outdoor, and personal VOC levels in 15 Seoul residents over a 3-month period using passive samplers. Results indicated that limonene had the highest concentrations across indoor, outdoor, and personal samples, with this compound primarily originating from household cleaners and air fresheners. Other VOCs, such as 2-butanone and toluene, also varied by location. Health risk assessments showed that most VOCs had a Hazard Index (HI) below 1, while the HI of individual exposures were relatively higher. Notably, cancer risk assessments for chloroform and ethylbenzene exceeded permissible levels in some scenarios, suggesting potential cancer risks. This underscores the importance of diverse microenvironment monitoring for accurate health risk evaluations, as relying solely on indoor and outdoor levels can underestimate actual exposure risks. This study highlights the need for future research to monitor VOC levels in various microenvironments, in addition to the necessity of investigating personal activity patterns in depth to accurately assess personal exposure levels. Such an approach is crucial for precise health risk assessments, and it provides valuable foundational data for evaluating personal VOC exposures.

Since 2010, the Odor Prevention Act has identified and regulated four types of fatty acids as substances that cause odors. Four types of fatty acids are contributors to odor pollution and are sensitive to changes in temperature and humidity. However, the current analysis method has several limitations, including dependency on the timing of sampling before and after the procedure, as well as dependency on the specific analysis method employed. The aim of this study is to assess the efficacy of the ion chromatography analysis method by utilizing ultrapure distilled water as a means to improve the current approach. Initially, the analysis system underwent a quality assessment. The results indicated a linearity (R2) of 0.99, a limit of 10 nmol/mol or lower, supporting the conclusion that it is suitable. Furthermore, the investigation focused on the substance’s tendency to change over time in ultrapure water and under alkali absorption (0.01N NaOH). At a concentration of 0.95 ng (low-concentration standard sample), the confirmed peak area values ranged from 0.0004 μg/min to 0.0010 μg/min, resulting in an injection variation of approximately ± 0.001. At 23.7 ng (high-concentration standard sample), the peak area value fluctuated between 0.008 μg/min and 0.013 μg/ min, with an average of ± 0.002. Therefore, storing the material at temperatures below 4°C for up to 3 days (72 hours) after manufacturing seemed to facilitate the optimal conditions for maintaining its stability without significant changes taking place. Finally, blank samples from the laboratory, equipment, and site were analyzed. Out of the four substances analyzed, only n-butyl acid was detected in all three background samples. It was confirmed that it represented 4% of the peak area in the 4.94 ng standard sample.