Epoxy-based composites find extensive application in electronic packaging due to their excellent processability and insulation properties. However, conventional epoxy-based polymers exhibit limitations in terms of thermal properties and insulation performance. In this study, we develop epoxy-based siloxane/silica composites that enhance the thermal, mechanical, and insulating properties of epoxy resins. This is achieved by employing a sol–gelsynthesized siloxane hybrid and spherical fused silica particles. Herein, we fabricate two types of epoxy-based siloxane/ silica composites with different siloxane molecular structures (branched and linear siloxane networks) and investigate the changes in their properties for different compositions (with or without silica particles) and siloxane structures. The presence of a branched siloxane structure results in hardness and low insulating properties, while a linear siloxane structure yields softness and highly insulating properties. Both types of epoxy-based siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are considerably improved by incorporating silica particles. We expect that our developed epoxy-based composites to hold significant potential as advanced electronic packaging materials, offering high-performance and robustness.

Two tree frogs, Dryophytes suweonensis and Dryophytes japonicus, inhabiting Korea, are morphologically similar and share the same habitats. Therefore, they are identified mainly through their calls, especially for males. Dryophytes suweonensis is registered as an endangered (IUCN: EN grade) and protected species in South Korea. Thus, it is necessary to develop a method to rapidly identify and discriminate the two species and establish efficient protection and restoration plans. We identified significant genetic variation between them by sequencing a maternallyinherited mitochondrial 12S ribosomal DNA region. Based on the sequence data, we designed a pair of primers containing 7 bp differences for high resolution melting (HRM) analysis to rapidly and accurately characterize their genotypes. The HRM analysis using genomic DNA showed that the melting peak for D. suweonensis was 76.4±0.06°C, whereas that of D. japonicus was 75.0±0.05°C. The differential melt curve plot further showed a distinct difference between them. We also carried out a pilot test for the application of HRM analysis based on immersing D. suweonensis in distilled water for 30 min to generate artificial environmental DNA (eDNA). The results showed 1.10-1.31°C differences in the melting peaks between the two tree frog samples. Therefore, this HRM analysis is rapid and accurate in identifying two tree frogs not only using their genomic DNA but also using highly non-invasive eDNA.

Namnabat et al. (cf., [Carbon Letters, https://doi.org/10.1007/s42823-020-00194-2]) employ the classical approach of Li and Chou (cf., [Int J Solids Struct 40: 2487–2499]) to the implementation of the molecular structural mechanics method using the Bernoulli–Euler beam elements for nonlinear buckling analysis of double-layered graphene nanoribbons. However, more recent studies by Eberhardt and Wallmersperger (cf., [Carbon 95: 166–180]) and others (see, e.g., [Int J Eng Sci 133: 109–131]) have shown that the classical approach of Li and Chou poorly reproduces both in-plane and out-of-plane mechanical moduli of graphene. We have shown that the 2D beam-based hexagonal material used by Namnabat et al. poorly simulates the mechanical moduli of graphene, especially the bending rigidity modulus, and this material cannot be used for the buckling simulation of graphene sheets (or nanoribbons). In addition, it is noted that in Int J Eng Sci 133: 109–131, a modification of the classical approach of Li and Chou is given which exactly reproduces both in-plane (2D Young’s modulus and Poisson’s ratio) and out-of-plane (bending rigidity modulus) mechanical moduli of graphene using beam elements.

Double-layer graphene nanoribbons promise potential application in nanoelectromechanical systems and optoelectronic devices, and knowledge about mechanical stability is a crucial parameter to flourish the application of these materials at the next generation of nanodevices. In this paper, molecular mechanics is utilized to investigate nonlinear buckling behavior, critical buckling stress, and lateral deflection of double-layered graphene nanoribbons under various configurations of stacking mode and chirality. The implicit arc-length iterative method (modified Riks method) with Ramm’s algorithm is utilized to analyze the nonlinear structural stability problem. The covalent bonds are modeled using three-dimensional beam elements in which elastic moduli are calculated based on molecular structural mechanics technique, and the interlayer van der Waals (vdW) interactions are modeled with nonlinear truss elements. An analytical expression for Young’s modulus of nonlinear truss elements is derived based on the Lennard–Jones potential function and implemented in numerical simulation with a UMAT subroutine based on FORTRAN code to capture the nonlinearity of the vdW interactions during the buckling analysis. The results indicate that the highest critical buckling stress and the minimum lateral deflection occur for armchair and zigzag chirality, both with AB stacking mode, respectively. Moreover, the critical buckling stress is found to be directly dependent on the mode shape number regardless of in-phase or anti-phase deflection direction of layers. Lateral deflection exhibits a similar trend with mode shape in anti-phase mode; however, it is decreasing by increasing mode shape number in in-phase mode.

컴퓨터 시스템의 발전과 더불어 과학적 이론의 수식화와 체계화를 통해 고분자 소재의 물성을 예측할 수 있는 다양한 종류의 시스템이 개발되어 왔으며 실제 분자동력학 시뮬레이션을 이용한 고분자 소재의 물성예측은 다양한 분야에 적용되어 왔다. 본 연구에서는 탄화수소계 고분자인 술폰화폴리아릴렌이서술폰 계　고분자와 상용화된 폴리이서술폰, 폴리비닐리덴플로라이드 고분자 소재를 이용한 블렌드 막을 제조하였으며, 제조된 분리막의 함량변화에 따른 이온과 메 탄올 투과물성 변화 예측에 대한 연구를 진행하였으며, 실제 실험결과와 비교분 석을 진행하였다.

본 연구에서는 술폰산기, 암모늄기를 가지는 폴리에테르에테르케톤계 고분자 소재에 대한 투과거동을 분석하기 위하여 분자 동력학 시뮬레이션을 이용하여 분석을 진행하였다. 술폰산기와 암모늄기의 함량을 조절하여 다양한 모델을 구 성하였으며, 도입된 관능기의 함량의 변화에 따른 하이드로니움, 히드록사이드 이온의 투과 거동에 대한 분석을 진행하였으며, 실제 실험 결과와 비교를 진행 하였다.

The phylogenetic relationships of species and genera in the subfamily Nymphalinae from Myanmar were inferred using mtDNA sequence data from 608 bp of cytochrome oxidase subunit I (COI). A total of 20 species in 10 genera were sequenced and used to construct phylogenetic trees. The base composition of COI sequences was 38.1% T, 15.6% C, 31.6% A, 14.7% G, revealing strong AT bias (69.7%). The sequence distance of 20 species of Nymphalinae ranged from 1.5% to 15.5%. The transition of nucleotide substitution was more common than transversion. The transition between T and C were higher than transition between A and G, and the transversion between A and T was the highest amongst other types of transversion. The phylogenetic trees were constructed using the neighbor-joining (NJ) and maximum likelihood (ML) methods and showed almost identical topologies. The results indicated that the tribes Junoniini and Nymphalini (sensu Wahlberg et al., 2005) formed monophyletic groups but Kallimini was not monophyletic group. Rhinoplapa polynice formed sister group to Junoniini clade with moderate support in both trees. The relationship of species in Junoniini was ((Junonia + Yoma) + Hypolimnas) and the relationship in Nymphalini was (Symbrenthia + (Vanessa + (Kaniska + Polygonia))). The clustering results were almost identical to current morphological classification.

옥수수 포장에서 발생하는 Trichogramma속 조명나방 알기생벌의 종 분포를 조사하기 위해 채집된 알기생벌로부터 핵내 ITS2 DNA 전체 염기서열 정보를 해독하였다. 그리고 종 구별을 위한 참고정보로 NCBI GenBank에 등록된 Trichogramma속 60종의 ITS2 전체 염기서열을 확보하여 비교하였다. 국내 채집 알기생벌은 ITS2 DNA 길이와 3′ 말단 염기서열 패턴에 따라 3개 그룹(K-1, -2, -3)으로 구분되었다. 국내 채집 그룹 내 염기서열 차이 추정값(Evolutionary distance, d)은 0.005 이하로 그룹 간 비교 시 d 값(≥0.080)보다 낮았다. 그룹 및 GenBank 등록 종 간 비교 시 K-1은 T. ostriniae, K-2는 T. dendrolimi, K-3은 T. confusum과 d 값이 각각 0.016, 0.001, 0.002로 가장 작았다. 추론된 분자계통수에서 K-1은T. ostriniae, K-2는 T. dendrolimi와 각각 분지되었으나 K-3는 T. confusum, T. chilonis, T. bilingensis와 함께 분지되었다. NCBI BLAST 결과에서도 K-1은 T. ostriniae와 K-2는 T. dendrolimi와 99% identity를 보였다. 그러나 K-3의 홍천 채집 기생벌들은 T. confusum, T. chilonis와 99-100% identity를 보였지만, 고창 채집 기생벌은 T. bilingensis, T. confusum, T. chilonis와 98% identity를 보였다. 이상의 분석 결과 본 연구에서 채집된 알기생벌 K-1과 K-2는 각각 T. ostriniae와 T. dendrolimi, 단일한 종으로 추정되었으나 K-3는 ITS2 정보만으로 종을 추정하기 어려웠다.

Local and seasonal populations of the oriental fruit moth, Grapholita molesta , were monitored with sex pheromone trapping and RAPD (random amplified polymorphic DNA) molecular marker to analyze their movement in apple orchards. To detect their movements among farms, pheromone traps were placed at regions between apple farms (‘outside-farms’) as well as within-farms (‘inside-farms’). Four seasonal adult peaks were evident in apple-cultivating fields from April to October in both trappings of inside- or outside-farms. After overwintering generation, populations of inside-farms were significantly reduced with frequent insecticide applications, compared to populations of outside-farms. Within apple farms, G. molesta tended to be unevenly distributed because of significant sublocal preference. Active movements of local and seasonal populations of G. molesta were supported by gene flow analysis using RAPD marker. Monitoring data using sex pheromone and seasonal reduction in initial genetic differentiation detected in the overwintering populations suggest that there must be significant movement of G. molesta among different orchards in apple-cultivating areas.

Background : Kalopanacis Cortex (海桐皮) is listed in「The Korea Pharmacopoeia (KP)」as the original plant of Kalopanax septemlobus (Thunb.) Koidz. However, the dried cortex of Erythrina eariegata L (刺桐) is an adulterant, one of the most indiscriminately used herbal medicines because of its similar morphologic. Due to the morphological similarities of the dried cortex of this plant to those of K. septemlobus which is used as a substitute herbal for E. eariegata, distinguish these two species is extremely difficult. Meanwhile, K. septemlobus is a polymorphic species, its morphological characteristics showed great diversity due to the different geographical and environmental factors. For this reason, it is conducted to develop molecular markers to distinguishing these K. septemlobus with E. eariegata by using conventional polymerase chain reaction (PCR). Methods and Results : In this study, In order to clearly identify origin of K. septemlobus, E. eariegata was analyzed from four barcode regions of chloroplast DNA (psbA-trnH, rbcL, matK, atpH-atpF) and nuclear ribosomal DNA (ITS2) to evaluate the ability of discrimination for each barcode region. The present study aimed to analyze the percent of variable sites were provided the highest ITS2 (2.3%) followed by rbcL (8.2%), in oder to develop a species-specific primer that can distinguish K. septemlobus form E. eariegata. Conclusion : The INDEL markers were developed based on the divergence of each sequence, and it is possible now to identify the two species of K. septemlobus with just a single performance of PCR. This will not only prevent misused of the plant, but also to maintain the quality of the herbal medicine as well as to verify and guarantee safety for public health.

Background : Chrysanthemi Indici Flos (甘菊) is listed in 「The Korea Herbal Pharmacopoeia (KHP)」as the original plant of Chrysanthemum indicum L. C. indicum was one of the most representative medicinal plants in Asteraceae, Dried flowers of this plant have been valid chemical composition such as flavonoids, phenylpropanoids, terpenoids, and polysaccharides, possessing broad spectrum antibacterial, antiviral, antihypertensive and anti-oxidation functions. Meanwhile, C. indicum was a polymorphic species, its morphological characteristics showed great diversity due to the different geographical and environmental factors. For this reason, there was conducted to develop molecular markers to distinguishing these C. indicum with C. morifolium, C. zawadskii var. latilobum and Aster spathulifolius by using conventional polymerase chain reaction (PCR). Methods and Results : In this study, In order to clearly identify origin of Chrysanthemi Indici Flos, these samples (C. indicum, C. morifolium, C. zawadskii var. latilobum and A. spathulifolius) were analyzed from five barcoding regions of chloroplast DNA (rbcL, matK, rpoB, atpF-atpH) and nuclear ribosomal DNA (ITS2) to evaluate the ability of discrimination for each barcoding region. Based on genetic distance, the percent of variable sites were provided the highest ITS2 value (56.9%), followed by atpF-atpH (48.18%), matK (27.2%), psbK (8.2%), and rbcL (2.9%). Comparative analysis based on the complete genome sequence of the petL-petG region INDEL (insertion/deletion) that the gene annotations were registered to the GenBank (accession number: JN-867592.1, NC-020092.1, MF-034027.1, NF-279514.1). Conclusion : From the above results, we may suggest that the petL-petG region INDEL analysis were conducted for molecular authentication of four plants (C. indicum, C. morifolium, C. zawadskii var. latilobum and A. spathulifolius). The findings of results indicated that petL-petG region might be established INDEL analysis systems and hence were proved to be an effective tools for molecular evaluation and comparison of “Chrysanthemi Indici Flos” with other plants.

Background : The Codonopsis genus belongs to the Campanulaceae, and it is recorded that there are four species of Codonopsis genus in Korea, such as Codonopsis lanceolata, Codonopsis pilosula, Codonopsis minima, and Codonopsis ussuriensis. C. lanceolata has been proved to be safety and efficacy, and has been widely used for medicinal and edible purposes for a long time in East Asian countries including Korea, China and Japan. However, little genetic research has been done. Methods and Results : Ten species of Codonopsis plants were collected and DNA was extracted using CTAB (cetyl trimethylammonium bromide) method. The extracted DNA was diluted to 5 ng/㎕ for the PCR (polymerase chain reaction) process. C. lanceolata genome was used to develop molecular markers by searching insertion and deletion regions (InDel) in the chloroplast sequence. The developed markers were applied to 4 individuals per Codonopsis species. PCR amplification was carried out using a denaturation at 94℃ for 30 sec, annealing at 58℃ for 30 sec and extension at 72℃ for 30 sec, repeated for 35 total cycles. The PCR products were separated in a 4% agarose gell at 100 V for 40 min. Conclusion : Using the molecular markers developed in this study, genetic diversity of Codonopsis genus was tested, and at the same time, a specific molecular marker was developed to differentiate C. lanceolata from the Codonopsis plants.