최근 국내에서는 온라인 거래를 통한 화훼류의 판매가 증가 하고 있다. 온라인 플랫폼의 종류에 따라서 각기 다양한 운송 시스템과 포장 방법을 이용하고 있지만, 품질과 관련된 정보가 부족한 실정이다. 특히, 일반 택배 배송을 이용하는 직거래 방식 은 다양한 외부 환경에 노출되기 때문에 품질에 문제가 발생할 수 있다. 절화장미는 외부의 환경에 노출되는 통기 구멍이 있는 포장 박스와 외부의 환경과 단절된 밀폐된 포장 박스가 사용되 고 있다. 포장 박스의 종류에 따른 절화장미의 품질을 조사한 결과 통기구가 있는 포장 박스를 이용하여 택배 운송한 절화장 미는 운송 중의 낮은 습도로 인해 생체중 감소가 높아 품질이 하락하였다. 밀폐된 포장 박스를 이용해서 운송한 절화장미는 통기 구멍이 있는 포장 박스를 이용해 운송한 절화장미보다 생 체중 감소는 작았지만, 포장 박스 내부의 온도가 높아져 품질이 하락하였다. 내부가 코팅된 밀폐형 포장박스 내부에 절화장미와 함께 냉매를 동봉하여 포장 후 운송하면, 운송 중 포장박스 내부 의 온도를 경감하고 품질을 보존하는 효과가 있었다.
This review paper provides a comprehensive analysis of the measurement and distribution of microplastics in the atmosphere and their role in the adsorption and transport of organic and inorganic pollutants. Due to their small size, large surface area, and hydrophobic nature, microplastics can adsorb a wide range of pollutants, including volatile organic compounds (VOCs) and heavy metals. These pollutants, strongly bound to the surface of microplastics, can remain suspended in the atmosphere for extended periods, facilitating the widespread distribution of contaminants. Building on existing research, this paper systematically reviews the sampling, pretreatment, and analytical methodologies applied to study microplastics in the air. Furthermore, it examines the influence of environmental factors on the adsorption and desorption dynamics of pollutants associated with microplastics. Various studies indicate that microplastics can interact with pollutants such as heavy metals, organic compounds, and microorganisms to form complex contaminants. These complexes can be transported and redistributed across long distances in the atmosphere, amplifying their environmental and health impacts. This review highlights that microplastics are not merely a pollutant themselves but serve as a vehicle for the migration and dispersion of other contaminants. This dual role emphasizes the significant risks microplastics pose to public health and the environment, necessitating further research and effective mitigation strategies.
Electrical and thermal transport properties of a polycrystalline carrier-doped wide-gap semiconductor LaCu1-δ S0.5Se0.5O (δ = 0.01), in which the CuCh (Ch = S, Se) layer works as conducting layer, were measured at temperatures 473~673 K. The presence of δ = 0.01 copper defects dramatically reduces the electrical resistivity (ρ) to approximately one part per million compared to that of δ = 0 at room temperature. The polycrystalline δ = 0.01 sample exhibited ρ of 1.3 × 10-3 Ωm, thermal conductivity of 6.0 Wm-1 K-1, and Seebeck coefficient (S) of 87 μVK-1 at 673 K. The maximum value of the dimensionless figure of merit (ZT) of the δ = 0.01 sample was calculated to be 6.4 × 10-4 at T = 673 K. The ZT value is far smaller than a ZT ~ 0.01 measured for a nominal LaCuSeO sample. The smaller ZT is mainly due to the small S measured for LaCu1-δS0.5Se0.5O (δ = 0.01). According to the Debye model, above 300 K phonon thermal conductivity in a pure lattice is inversely proportional to T, while thermal conductivity of the δ = 0.01 sample increases with increasing T.
In this paper, we developed a thermoelectric storage container that maintains whole blood temperature and studied its characteristics. Using a temperature sensor, we compared the internal temperature with the set temperature in real time and maintained the temperature between 1 and 6°C. In addition, we installed insulation inside the container and used a lithium-ion battery to power the system to ensure a stable whole blood temperature even during long-distance transportation. Instead of a blood pack, a 350-g water bottle was used and the experiment was conducted at an ambient temperature of 25°C. After cooling for 10 minutes, the internal temperature of the container reached 6°C and the battery operated for 60 minutes. In the future, if we improve the thickness and thermal conductivity of the insulation installed in the thermoelectric storage container and utilize phase change materials as a supplement, we will be able to transport more diverse blood products and special reagents stably.
그래핀 산화물(GO), 폴리에틸렌 글리콜 다이아크릴레이트(PEGDA), 폴리에틸렌 글리콜 메틸 에터 아크릴레이트 (PEGMEA)의 나노복합체를 자외선 광중합을 통해 합성하였다. GO는 가교된 폴리에틸렌 옥사이드(XPEO) 매트릭스 내에 최 대 1.0 wt% 농도까지 균일하게 분산시켰다. 더 높은 농도에서는 GO가 응집되는 경향을 보였다. 잘 분산된 GO는 친수성 PEO 사슬과 추가적인 화학적 가교 네트워크를 형성했다. XPEO-GO 나노복합체는 GO 농도에 따라 기계적 강도 및 염과 가 스에 대한 차단 특성이 향상된 것으로 나타났다. 이 연구는 다양한 GO 농도와 플레이크 크기를 가진 XPEO-GO 하이드로겔 의 제조 및 특성화를 다루고 있다. 이러한 특성은 나노복합 하이드로겔이 강화된 XPEO 기반 바이오소재 및 고급 항균성 한 외여과(UF) 친수성 코팅에서의 잠재적 응용 가능성을 시사한다.
PURPOSES : This study empirically examines the determinants of traffic accidents by focusing on the transport culture index. METHODS : Two-stage least-squares estimation using an instrumental variable is used as the identification strategy. As the instrumental variable of the transport culture index, its past values, particularly before the outbreak of COVID-19 in 2018 are used. RESULTS : The empirical results, considering the potential endogeneity of the transport culture index, show that areas with higher values of the index are likely to have fewer traffic accident casualties. Local governments of regions with relatively frequent traffic accidents can run campaigns for residents to fasten their seatbelts, causing reverse causation. Ignoring this type of endogeneity underestimates the importance of the index as a key determinant of traffic accidents. CONCLUSIONS : Several traffic accidents occur in Korea, e.g., 203,130 accidents with 291,608 injuries and 5,392 deaths. As traffic accidents cause social costs, such as delays in traffic flow and damage to traffic facilities, public interventions are required to reduce them. However, the first step in public intervention is to accurately understand the relationship between the degree of damage in traffic accidents and the transport-related attributes of the areas where the accidents occurred. Although the transport culture index appears to be an appropriate indicator for predicting local traffic accidents, its limitations as a comprehensive index need to be addressed in the future.
Shipping universally accounts for 80% of global trade and 70% in price terms. While in Vietnam, not only the maritime transport market share, especially with international goods, has decreased significantly but also the maritime transport volume of national fleet tends to decrease. Therefore, the solutions of increasing the transport volume along with regaining the transport market share are a major concern for Vietnam's shipping development plan. With the purpose of finding these important solutions, this research aims at investigating the factors affecting the national fleet’s transport volume by ARDL model based on Vietnamese fleet’s transport volume quarterly data from 2008 to 2022. The results demonstrate that the deadweight tonnage of the fleet and GDP are the two fundamental factors which have positive influences on transport volume of Vietnamese shipping fleet in both the short run and the long run. Then, the paper proposes solutions how these two variables, especially the tonnage of the fleet increase the maritime transport market share as well. The findings provide clear directions to the policy makers and the shipping company in proposing relevant solutions for shipping development plan.