Koreoleptoxis nodifila (Martens, 1886) is an endangered species only living in the central and north streams of South Korea. However, there is a lack of information on physical habitat characteristics of K. nodifila. We aimed to determine preference ranges for water depth, current velocity, streambed substrate of K. nodifila. The weibull model was used to estimate the habitat suitability based on distribution of individual abundance by physical factors. Optimal depth preferences ranged from 0.53~17.17 cm, current preferences ranged from 48.40~81.03 cm s-1 and substrate (Φm) preferences ranged from - 4.36~ - 2.26. Median values of central tendency were determined as follows: water depth 16.73 cm, current velocity 65.23 cm s-1, substrate - 3.51. Mean values of central tendency were determined as follows: water depth 21.32 cm, current velocity 65.65 cm s-1, substrate - 3.63. Mode values of central tendency were determined as follows: water depth 5.17 cm, current velocity 64.77 cm s-1, substrate - 3.24. Based on the habitat suitability analysis, the microhabitat types of K. nodifila were determined as riffle and coarse-grained streambed.

지중관수에 의한 밭작물의 농업용수는 30%이상 절감되고 가용용수량도 지표면 관수에 비해 2배 이상의 효과가 있는 것으로 알려져 있다. 이것은 수분을 지중에 공급하므로 증발산으로 인한 손실을 줄일 뿐만 아니라 지중의 확산 체적을 넓혀 지표면에 비해 수분공급 효과를 높일 수 있기 때문이다. 뿐만 아니라 관수 노동력도 절감되므로 최근 지중관수 장치의 보급이 확산되고 있는 추세이다. 그러나 우리나라는 아직까지 지중관수 장치가 개발되지 않아 농민들은 수입품 자재에 의존하고 있는 실정이다. 지중관수 장치는 3가지 중요한 기능을 가지고 있다. 첫 번째는 공급압력 100-400 kPa 사이에 유량 오차가 5-10% 범위에서 균등해야 하고, 두 번째는 토양속에서 수분을 공급하므로 뿌리가 토출구 속으로 들어가 내부의 관수구가 막히지 않아야 한다. 세 번째는 용수 공급을 중단했을 때, 관수구에서 누수가 되지 않도록 설계⋅제작되어야 한다. 또한 지중에 수분을 공급하므로 지표면 관수와 달리 이상 유무에 대해 확인하기 어려운 점이 있기 때문에 장치의 신뢰성이 높아야 한다. 따라서 지중관수 장치의 핵심은 3가지 기능을 가진 드리퍼의 개발이 우선되어야 가능하다. 유량의 균등성을 유지하는 것은 드리퍼 내부에 압력보상 기술(pressure compensation technology)에 의해 좌우된다. 드리퍼는 outer, lower insert 및 upper insert의 구성요소로 이루어져 있고, 내부에 압력조정 기능 즉, 밸브의 역할을 하는 실리콘이 내장되어 있다. 드리퍼가 유량 균등성, 뿌리 막힘 및 역류방지 기능을 수행하기 위해서 약 10가지의 설계변수를 고려해야 한다. 특히 드리퍼에서 유량이 가장 먼저 통과하는 outer의 원추 높이와 실리콘 경도는 유량 균등성에 미치는 영향이 가장 클 뿐만 아니라 공급유량의 중지 시에는 역류방지의 기능도 동시에 하게 된다. 본 연구에서 개발된 지중관수용 드리퍼의 유량 균등성은 95%를 목표로 하였다. 또한 국내서 개발한 4종의 개발품과 2종의 해외 제품을 대상으로 뿌리 침투 장면도 확인하였고, 역류 방지기능에 대해서는 관수중단점 압력 29 kPa에서 관수가 중단되는 것으로 나타나 성능이 우수한 것으로 판단되었다.

Purpose: This study aims to investigate the effect of a simulation-based patient safety performance improvement education program on caregivers’ knowledge, attitude, and performance toward safety. Methods: This study adopted a quasi-experimental design that applied before-and-after designs for the test and control groups. It was configured focusing on “infectious disease,” “fires,” “falls,” and “drug abuse.” Results: There was a significant difference in knowledge and patient safety performance between the experimental group and the control group. However, there was no significant difference in attitudes toward safety. Conclusion: The results of this study showed that the simulation-based patient safety performance improvement education program is effective in improving patient safety performance. Therefore, it is necessary to continuously apply and evaluate the simulation-based patient safety performance training program to enable caregivers to develop professional prevention and management capabilities within elderly care facilities

Porous ceramics have the advantages of low density, low thermal conductivity, and excellent mechanical properties. Among porous ceramic manufacturing methods, the replica template method allows the easy manufacturing of porous filters with the highest porosity and pores of the desired size, but it also has the disadvantage that the resulting filters have low mechanical strength. To overcome this shortcoming, mullite (3Al2O3·2SiO2) whiskers, which have excellent thermal stability and high mechanical strength, were introduced in porous ceramic structure. The mullite whiskers were synthesized using a composition of Al2O3, flyash and MoO3. The morphologies and crystal structures of the mullite whiskers with MoO3 contents were investigated in detail. When the porous ceramic with mullite whiskers was fabricated using 20 wt% MoO3 catalyst the most uniform microstructure was obtained, and the mullite whiskers showed the highest aspect ratio of 47.03. The porosity and compressive strength of the fabricated porous ceramic were 82.12% and 0.83 MPa, respectively.

This study analyzed the allocation of the skipper’s attention during fishing operation in the wheelhouse of a Korean coastal composite fishing vessel by using video observation. To summarize the results, the ratio of lookout, radar and GPS monitoring, which is essential for prevention of collision at sea, was significantly lower than that of other fishing operation due to the attention concentration on the work place during hauling line. In order to reduce exposure to risk of collisions due to concentration of attention to certain tasks such as line hauling, it is necessary to develop an alert system that can notify the approach of other ships or obstruction throughout the ship using information from radar or the automatic identification system. In addition, the order of attention allocation to devices and facilities obtained in this study is expected to be used as basic data for device or facility layout based on the principle of usage frequency in designing wheelhouse for coastal composite fishing vessels in the future.

본 실험에서는 α-Al2O3 세라믹 중공사를 지지체로 사용하였고, 무전해 도금을 통해 Pd 및 Pd-Ag가 도금된 수소 분리막을 제조하였다. Pd-Ag 분리막은 Pd와 Ag 합금 형태로 만들기 위하여 500°C, 10 h 동안의 annealing 과정을 거쳤으며, EDS (Energy Dispersive X-ray Spectroscopy) 분석을 통해 Pd-Ag 합금이 되었다는 것을 확인하였다. 또한, SEM (Scanning Electron Microscope) 분석을 통해 제조된 Pd 및 Pd-Ag 도금층의 두께는 약 8.98, 9.29 μm으로 측정되었다. 제조된 수소 분 리막은 350~450°C, 1-4 bar의 범위에서 수소 단일 가스, 혼합가스(H2, N2)를 이용하여 수소 투과 실험을 진행하였다. 수소 단 일 가스에서 Pd와 Pd-Ag 분리막은 최대 각각 21.85, 13.76 mL/cm2⋅min의 flux를 가지며, 혼합가스에서는 450°C, 4 bar의 조건일 때, 1216, 361의 separation factor가 각각 나오는 것을 확인하였다.

The present study was performed to investigate the effects of NH3-N and nitrifying microorganisms on the increased BOD of downstream of the Yeongsan river in Gwangju. Water samples were collected periodically from the 13 sampling sites of rivers from April to October 2021 to monitor water qualities. In addition, the trends of nitrogenous biochemical oxygen demand (NBOD) and microbial clusters were analyzed by adding different NH3-N concentrations to the water samples. The monitoring results showed that NH3-N concentration in the Yeongsan river was 22 times increased after the inflow of discharged water from the Gwangju 1st public sewage treatment plant (G-1-PSTP). Increased NH3-N elevated NBOD levels through the nitrification process in the river, consequently, it would attribute to the increase of BOD in the Yeongsan river. Meanwhile, there was no proportional relation between NBOD and NH3-N concentrations. However, there was a significant difference in NBOD occurrence by sampling sites. Specifically, when 5 mg/L NH3-N was added, NBOD of the river sample showed 2-4 times higher values after the inflow of discharged water from G-1-PSTP. Therefore, it could be thought other factors such as microorganisms influence the elevated NBOD levels. Through next-generation sequencing analysis, nitrifying microorganisms such as Nitrosomonas, Nitroga, and Nitrospira (Genus) were detected in rivers samples, especially, the proportion of them was the highest in river samples after the inflow of discharged water from G-1-PSTP. These results indicated the effects of nitrifying microorganisms and NH3-N concentrations as important limiting factors on the increased NBOD levels in the rivers. Taken together, comprehensive strategies are needed not only to reduce the NH3-N concentration of discharged water but also to control discharged nitrifying microorganisms to effectively reduce the NBOD levels in the downstream of the Yeongsan river where discharged water from G-1-PSTP flows.

Known for its effectiveness in weight loss and diabetes prevention, Gymnema sylvestre products can be found in the US, Japanese, and Indian markets. However, the recommended dosage or safety of these products has not yet been proven. Therefore, development of an analytical method for detecting the content of Gymnema sylvestre in food products is required. Accordingly, this study proposes an analysis method that can examine Gymnema sylvestre in food using LC-ESI-MS/MS and KASP (Kompetitive Allele-Specific PCR) markers. In LC-ESI-MS/MS, a simultaneous analysis method for gymnemic acid and deacylgymnemic acid was optimized using negative ionization mode, and its validation test was completed for solid and liquid samples. In addition, KASP markers were prepared by finding the specific SNP of G. sylvestre in ITS2 and matK through DNA barcodes. The two KASP markers returned positive FAM fluorescence result when combined with G. sylvestre, and this aspect was confirmed in raw G. sylvestre as well. The applicability of the method was tested on 21 different food and healthy functional products containing G. sylvestre purchased on the internet. As a result, although there was a difference in the ratios of gymnemic acid and deacylgymnemic acid in LC-ESI-MS/MS, the index component was detected in all 21 products samples. In the KASP analysis, 9 products returned positive FAM result, and the rest of the products were found to be containing G. sylvestre extract. This study is the first study to use the dual system of LC-ESI-MS/MS and KASP for the analysis of G. sylvestre. The study has confirmed that these two methods are applicable to the examine G. sylvestre content in food products.