• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2603-2606
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• 2010

Novel soluble triazoleimide oligomers terminated with arylacetylene terminated were synthesized by the Cu(I)-catalysed 1,3-dipolar cycloaddition polymerization of diazides and imide-containing dialkyne. Several molecular weight triazoleimide oligomers were prepared from diazide and dialkyne monomers with different stoichiometric combinations. The curing behaviors of the oligomers were tested by differential scanning calorimetry (DSC). The thermal properties of the cured products were evaluated by DSC and thermogravimetric analysis (TGA). These cured oligomers showed the glass transition temperature of about $225-235^{\circ}C$ and the decomposition temperature (at 5% weight loss) of about $385-393^{\circ}C$ in nitrogen.

• 정보보호학회논문지
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• 제14권3호
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• pp.75-84
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• 2004

이 논문에서는 블록 암호 알고리즘 GOST의 연관키 차분 공격에 대하여 설명한다. COST는 키 스케줄이 단순하여 연관키 차분 특성식이 발생하는데 이를 이용하여, 우선 랜덤 oracle로부터 GOST 블록 암호 알고리즘을 확률 1-2$^{-64}$ 로 써 구별하는 방법에 대하여 언급하고, 그 다음엔 각각 24-라운드와 6-라운드로 이루어진 두 개의 연관키 차분 특성식을 연접하여 30-라운드 차분 특성식을 꾸민 후 31-라운드 GOST의 마지막 라운드 키 32비트를 복구하는 공격방법에 대하여 설명한다. 또한, 전체 32-라운드 GOST의 마지막 32 라운드의 부분키 12 비트를 91.7%의 성공확률로 2$^{35}$ 의 선택평문과 2$^{36}$ 의 암호화 시간을 이용하여 복구할 수 있는 알고리즘에 대해서 서술한다.

• Journal of Platform Technology
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• 제11권1호
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• pp.72-84
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• 2023

With the rise of the Internet of Things, the security of such lightweight computing environments has become a hot topic. Lightweight block ciphers that can provide efficient performance and security by having a relatively simpler structure and smaller key and block sizes are drawing attention. Due to these characteristics, they can become a target for new attack techniques. One of the new cryptanalytic attacks that have been attracting interest is Neural cryptanalysis, which is a cryptanalytic technique based on neural networks. It showed interesting results with better results than the conventional cryptanalysis method without a great amount of time and cryptographic knowledge. The first work that showed good results was carried out by Aron Gohr in CRYPTO'19, the attack was conducted on the lightweight block cipher SPECK-/32/64 and showed better results than conventional differential cryptanalysis. In this paper, we first apply the Differential Neural Distinguisher proposed by Aron Gohr to the block ciphers HIGHT and GOST to test the applicability of the attack to ciphers with different structures. The performance of the Differential Neural Distinguisher is then analyzed by replacing the neural network attack model with five different models (Multi-Layer Perceptron, AlexNet, ResNext, SE-ResNet, SE-ResNext). We then propose a Related-key Neural Distinguisher and apply it to the SPECK-/32/64, HIGHT, and GOST block ciphers. The proposed Related-key Neural Distinguisher was constructed using the relationship between keys, and this made it possible to distinguish more rounds than the differential distinguisher.

• The Korean Journal of Physiology and Pharmacology
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• 제23권3호
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• pp.161-169
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• 2019

Fumigaclavine C (FC), an active indole alkaloid, is obtained from endophytic Aspergillus terreus (strain No. FC118) by the root of Rhizophora stylosa (Rhizophoraceae). This study is designed to evaluate whether FC has anti-adipogenic effects in 3T3-L1 adipocytes and whether it ameliorates lipid accumulation in high-fat diet (HFD)-induced obese mice. FC notably increased the levels of glycerol in the culture supernatants and markedly reduced lipid accumulation in 3T3-L1 adipocytes. FC differentially inhibited the expressions of adipogenesis-related genes, including the peroxisome proliferator-activated receptor proteins, CCAAT/enhancer-binding proteins, and sterol regulatory element-binding proteins. FC markedly reduced the expressions of lipid synthesis-related genes, such as the fatty acid binding protein, lipoprotein lipase, and fatty acid synthase. Furthermore, FC significantly increased the expressions of lipolysis-related genes, such as the hormone-sensitive lipase, Aquaporin-7, and adipose triglyceride lipase. In HFD-induced obese mice, intraperitoneal injections of FC decreased both the body weight and visceral adipose tissue weight. FC administration significantly reduced lipid accumulation. Moreover, FC could dose-dependently and differentially regulate the expressions of lipid metabolism-related transcription factors. All these data indicated that FC exhibited anti-obesity effects through modulating adipogenesis and lipolysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3815-3833
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• 2021

MILP-based automatic search is the most common method in analyzing the security of cryptographic algorithms. However, this method brings many issues such as low efficiency due to the large size of the model, and the difficulty in finding the contradiction of the impossible differential distinguisher. To analyze the security of ESF algorithm, this paper introduces a simplified MILP-based search model of the differential distinguisher by reducing constrains of XOR and S-box operations, and variables by combining cyclic shift with its adjacent operations. Also, a new method to find contradictions of the impossible differential distinguisher is proposed by introducing temporary variables, which can avoid wrong and miss selection of contradictions. Based on a 9-round impossible differential distinguisher, 15-round attack of ESF can be achieved by extending forward and backward 3-round in single-key setting. Compared with existing results, the exact lower bound of differential active S-boxes in single-key setting for 10-round ESF are improved. Also, 2108 9-round impossible differential distinguishers in single-key setting and 14 12-round impossible differential distinguishers in related-key setting are obtained. Especially, the round of the discovered impossible differential distinguisher in related-key setting is the highest, and compared with the previous results, this attack achieves the highest round number in single-key setting.

• 정보보호학회논문지
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• 제28권4호
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• pp.803-807
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• 2018

Fantomas와 Robin은 FSE 2014에서 제안된 경량 블록암호 패밀리 LS-designs에 포함되는 블록암호로, 비트슬라이스 구현이 가능한 L-Box와 S-Box를 사용하여 부채널 분석 대응기법인 마스킹 기법을 효율적으로 적용할 수 있도록 설계되었다. 본 논문은 연관키 차분경로 분석을 통한 Fantomas와 Robin의 전체 128비트 키의 복구공격이 각각 $2^{56}$, $2^{72}$의 시간 복잡도와 $2^{52}$, $2^{69}$개의 선택 평문으로 가능함을 보인다.

• 대한물리의학회지
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• 제18권4호
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• pp.37-45
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• 2023

PURPOSE: The coexistence of age-related skeletal muscle mass loss and obesity poses a substantial health risk for individuals because it combines the detrimental effects of muscle mass reduction associated with aging and the health complications from obesity. This study aimed to identify the incidence rate and key influencing elements among Korean men in their thirties. METHODS: A cross-sectional study involving 934 male participants was performed using complex sampling analysis. Various influencing elements were investigated, including age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking behaviors, systolic and diastolic blood pressure, fasting glucose levels, triglyceride, and cholesterol levels. RESULTS: The incidence rate was 2.90%. The key influencing elements were age, height, weight, body mass index, waist circumference, skeletal muscle index, systolic blood pressure, fasting glucose, triglyceride, and total cholesterol (p < .05). CONCLUSION: This study identified the incidence rate and key influencing element for CALSMO among Korean younger community-dwelling men.

• ALGAE
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• 제38권4호
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• pp.283-294
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• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.976-980
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• 2010

A series of arylacetylene resins with siloxane units were synthesized by the condensation reactions of m-diethynylbenzene magnesium reagents with various $\alpha,\omega$-bis(chloro)dimethylsiloxanes. These resins are liquids and are miscible with common organic solvents at room temperature. The structures of the resins were characterized by FT-IR, $^1H$ NMR, $^{13}C$ NMR, $^{29}Si$ NMR, and gel permeation chromatography (GPC). The thermal behaviors of the resins were examined with differential scanning calorimetry (DSC). These resins have good processability. They can be thermally cross-linked through the ethynyl groups to produce cured resins. The thermal and thermooxidative stabilities of the cured resins were studied by thermogravimetric analysis (TGA). The cured resins possess high thermal and thermooxidative stability. Their decomposition occurs at above $500^{\circ}C$ in both $N_2$ and air. With increasing the length of siloxane units in the resins, the thermal stability of the cured resins decreases in $N_2$. When the cured resins were sintered above $1450^{\circ}C$ under argon, hard and glassy SiOC ceramics were obtained. These SiOC ceramics have the decomposition temperatures at 5% weight loss above $800^{\circ}C$ in air.

• Carbon letters
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• 제25권
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• pp.50-54
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• 2018

Large-size graphene samples are successfully prepared by combining ultrosonic assisted liquid phase exfoliation process with oxidation-deoxidation method. Different from previous works, we used an ultrasound-treated expanded graphite as the raw material and prepared the graphene via a facile oxidation-reduction reaction. Results of X-ray diffraction and Raman spectroscopy confirm the crystal structure of the as-prepared graphene. Scanning electron microscopy images show that this kind of graphene has a large size (with a diameter over $100{\mu}m$), larger than the graphene from graphite powder and flake graphite prepared through single oxidation-deoxidation method. Transmission electron microscopy results also reveal the thin layers of the prepared graphene (number of layers ${\leq}3$). Furthermore, the importance of preprocessing the raw materials is also proven. Therefore, this method is an attractive way for preparing graphene with large size.