This paper describes an adaptive hybrid evolutionary firefly algorithm for a topology optimization of truss structures. The truss topology optimization problems begins with a ground structure which is composed of all possible nodes and members. The optimization process aims to find the optimum layout of the truss members. The hybrid metaheuristics are then used to minimize the objective functions subjected to static or dynamic constraints. Several numerical examples are examined for the validity of the present method. The performance results are compared with those of other metaheuristic algorithms.

For the practical application of U-flanged Truss Hybrid beams, the flexural capacity of hybrid beams with end reinforcement details using vertical steel plates was verified. The bending test of U-flanged Truss Hybrid beams was performed using the same top chord under the compressive force, but with the thickness of the bottom plate and the amount of tensile reinforcement. The initial stiffness and maximum load of the specimen with tensile reinforcement have a higher value than that of the specimen without tension reinforcement, but the more tensile reinforcement, the greater the load decrease after the maximum load. In the case of the specimen with tensile reinforcement, because the test result value is 76% to 88% when compared with the flexural strength according to Korea Design Code, the safety of the U-flanged Truss Hybrid beam with the same details of the specimens can’t ensure. Therefore, the development of new details is required to ensure that the bottom steel plate and the tensile reinforcement can undergo sufficient tensile deformation.

This study aimed to determine the trend in dry matter yield (DMY) of a new sorghum-sudangrass hybrid (SSH) in the central inland regions of Korea. The metadata (n=388) were collected from various reports of the experiments examining the adaptability of this new variety conducted by the Rural Development Administration (1988–2013). To determine the trend, the parameters of autoregressive (AR) and moving average (MA) were estimated from correlogram of Autocorrelation function (ACF) and partial ACF (PACF) using time series modeling. The results showed that the trend increased slightly year by year. Furthermore, ARIMA (1, 1, 0) was found to be the optimal model to describe the historical trend. This means that the trend in the DMY of the SSH was associated with changes over the past two years but not with changes from three years ago. Although climatic variables, such as temperature, precipitation, and sunshine were also considered as environmental factors for the annual trends, no clear association was observed between DMY and climates. Therefore, more precise processing and detailed definition of climate considering specific growth stages are required to validate this association. In particular, research on the impact of heavy rainfall and typhoons, which are expected to cause damage in the short term, on DMY trends is ongoing, and the model confirmed in this study is expected to play an important role in studying this aspect. Furthermore, we plan to add the environmental factors such as soil and cultivation management as well as climate to our future studies.

Numerous studies have addressed the commercial viability of lithium–air batteries (LABs). However, the high reactivity of Li with air moisture and CO2 has hindered the broad applicability of LABs. In this study, lithium-protective hybrid lithium–air batteries (HLABs) were fabricated with Super P (SP) and composites of fluorinated carbon ( CFx), MoS2, and WS2 as the cathodes. Subsequently, their potential use as a power source for the next generation of defense technologies was investigated. It was observed that a single cell HLAB with the SP-CFx composite cathode exhibited a specific capacity of 893 mAhg− 1 cathode. In comparison, a Tomcell with the SP cathode demonstrated a specific capacity of 465 mAhg− 1 cathode when discharged. The cells with SP-MoS2 and SP-WS2 cathode yielded specific capacities of 357 and 386 mAhg− 1 cathode, respectively. The improved performance of the SP-CFx cell can be attributed to synergistic effects of lithium–air cell and lithium battery reactions between CFx and SP. To assess all functionalities of the SP-CFx HLAB, lithium-protective HLABs were fabricated and discharged in air. To operate the lithium–air battery in air, pure lithium metal was sealed with solid electrodes (lithium-ion conducting glass–ceramics (LICGC)) and a buffer electrolyte (1 M LiFTSI in TEGDME) was applied. The SP-CFx cell was discharged for 25 days in air, greatly exceeding the 72 h requirement for the next-generation soldier power systems. These results demonstrate significant potential for HLABs to be used as a pioneering power source in nextgeneration energy-independent tactical defense units.

Using UV nanoimprint lithography(UV-NIL), 1-dimensional(1-D) pattern structures were fabricated on a hybrid mixture thin film of lanthanum oxide and a UV-curable resin. 1-D pattern on a wafer fabricated by the laser interference lithography was transferred to polydimethylsiloxane and this is used as a mold of UV-NIL process. Conducting an X-ray photoelectron spectroscopy, C 1s and La 3d spectra were analyzed, and it was confirmed that hybrid thin film was successfully deposited on glass substrate. Also, transferred pattern structure was observed by using an atomic force microscopy. Through this, it was revealed that agglomerations between 1-D pattern were increased as UV irradiation time increased and this phenomenon disrupted the quality of NIL process. Additionally, liquid crystal(LC) cells with patterned hybrid thin films were fabricated and LC alignment performances were investigated. Using the polarizing optical microscopy and the crystal rotation method, LC alignment state and pretilt angles were observed. Consequently, the uniform homogeneous LC alignment was achieved at UV irradiation time of 1min and 3min where high resolution pattern transfer was observed.

The U-flanged truss hybrid beam is a new composite beam made by pouring concrete into the U-flanged truss beam. In this study, an experimental study was performed to verify the shear capacity of U-flanged truss hybrid beams with the newly developed end reinforcement details. For all specimens, the maximum shear strength was determined by shear failure of concrete in the loading point The detail reinforced with stirrups at the end zone can exhibit the greatest shear strength, but the method of reinforcing the end zone using vertical steel plates, which is a relatively easy method to manufacture, is considered to be the most effective detail in terms of shear strength and ductility. Also, in the case of U-flanged truss hybrid beams reinforced with vertical steel plates at the end zone, the shear strength can be evaluated on the safety side by using the Korea Design Standard formula.

배경/목적: 본 연구는 증증급성호흡기증후군(COVID-19)의 확산에 따라 학술행사의 방식이 직접 참석에서 비대면 온라인 방식으로 점차 변화되는 현재의 경향을 고려하여, 2020년 시행된 학술행사 참석자들의 만족도를 분석한 연구이다. 설문조사를 통해 비대면 온라인 학술대회의 장점과 단점을 분석하고, 이를 토대로 향후 이상적인 학술대회를 준비할 수 있는 자료를 수립하고자 하였다. 방법: 2020년 상반기에 서울에서 개최된 ‘IC-KPBA 2020’ 학술행사의 참석자를 대상으로 18개 문항으로 구성된 설문조사를 시행하였다. 설문조사는 네이버 설문조사의 플랫폼을 이용하여 진행되었다. 결 과 : 비대면 온라인 방식의 학술행사에 대해서 학회 참석자들은 전반적으로 만족 혹은 매우 만족스럽다고 응답하였다. 온라인 참석자들은 네트워크 연결, 화면 및 음향 등의 각각의 항목에서 약 70-85%가 만족 혹은 매우 만족으로 응답하였으며, 직접 참석자들을 대상으로 한 설문에서 방역대책 및 현장의 화면, 음향 시설 등의 각각의 항목에서 약 80-90%가 만족 혹은 매우 만족으로 응답하였다. 향후 학회 참석 방식의 선호도 조사에서는 가급적 온라인을 선택하겠다는 답변이 33% 로 가장 높게 나타났다. 결론: 학술행사의 방식이 점차 비대면 온라인으로 변화되는 추세에서 대한췌장담도학회 주관 하에 새로운 방식으로 개최한 국제학술대회에 대한 만족도는 전반적으로 양호-우수한 것으로 확인되었다.

In this research, carbon nanotubes(CNT) and graphene nanoplates(GnP) are deposited on the surface of carbon fibers(CF) at once. Investigating the effect between CNT and GnP on increasing the interfacial and mechanical properties of carbon fiber reinforced epoxy composites(CFRP). The cross section of the CFRP composites indicates that the GnPs/CNTs hybrid coating exhibits significantly higher mechanical performance in all coating samples. The interlayer shear strength of the GnPs/CNT hybrid coated CFRP composite was 90% higher than that of the uncoated CF composite. The flexural and tensile strength of CFRP composites using GnPs /CNT hybrid coatings were improved by 52% and 70%, respectively, compared to uncoated CF.

1. 본 연구는 GM콩이 비의도적으로 자연에 방출되었을 시 야생콩과의 교잡에 의해 발생 가능한 교잡콩을 모니터링하고 영양학적 측면에서 안전성을 평가하기 위하여 수행하였다. 이를 위해, 베타카로틴 강화 GM콩과 야생콩, 두 품종간 인위적으로 생산한 교잡콩, GM콩의 모본이자 일반 재배 품종인 광안콩 등 4품종을 국내 2개 지역에서 재배하고 콩 종자를 대상으로 주요 영양성분 38종을 분석하였다. 2. 재배 환경에 영향을 받지 않고, GM콩 및 야생콩과 비교해 교잡콩에서 유의적 차이를 보이는 성분은 조단백질, 조섬유, alanine, glycine, leucine, serine, tryptophan, oleic acid, linolenic acid, arachidonic acid 등 10종이었다. 하지만, 분석한 모든 시료의 성분은 국내외 자연 범위에 포함되는 수준이었다. 3. PCA분석 결과, 주요 영양성분 함량 변이는 GM콩은 모본과 유사하였고, 교잡콩은 GM콩 보다는 야생콩과 유사하였다. 즉, 분석한 4품종의 영양성분의 변이는 재배 환경보다는 유전적 요인에 의해 더 크게 영향을 받음을 알았다. 4. 본 연구의 결과는 GM콩과 야생콩간 교잡콩의 영양학적 안전성을 분석한 최초의 보고이며, 이는 향후 GM콩의 비의도적 자연 방출을 모니터링하는데 있어 유용한 기초 자료로써 활용 가치가 있을 것이다.