• Nano
• /
• 제13권12호
• /
• pp.1850144.1-1850144.13
• /
• 2018

A nano-$MoS_2$/montmorillonite K-10 (K10) composite was prepared and characterized. The composite contains two types of 2H-$MoS_2$ nanoparticles. One is the hollow spherical $MoS_2$ with a size range of 75 nm, and the other is the spherical nano cluster of $MoS_2$ with a size range of 30 nm. The two kinds of nano-$MoS_2$ were formed via assembly of numerous $MoS_2$ nano-platelets with a size of ~10 nm. A tribological comparison was then made among nano-$MoS_2$/K10, K10, nano-$MoS_2$ and a mechanical mixture of K10 and nano-$MoS_2$. K10 reduced the wear but slightly increased the friction. Nano-$MoS_2$ remarkably reduced both friction and wear. The mechanical mixture demonstrated better wear resistance than nano-$MoS_2$, indicating a synergistic anti-wear effect of nano-$MoS_2$ and K10. The synergistic effect was reinforced using nano-$MoS_2$/K10 instead of the mechanical mixture. A part of the $MoS_2$ in the contact region always lubricated the friction pair, and the rest formed a tribofilm. K10 segregated the friction pair to alleviate the ablation wear but magnified the abrasive wear. S-$MoS_2$ protects K10 and they together function as both a lubricant and an isolating agent to reduce the ablation and abrasive wear.

• 한국표면공학회지
• /
• 제53권6호
• /
• pp.351-359
• /
• 2020

Formation behavior and properties of PEO (Plasma Electrolytic Oxidation) film on AA2024 were investigated under application of pulsed current as a function of Na3PO4 concentration in 0.05 M Na2SiO3 solution by analyzing voltage-time behavior, in-situ observation of arc generation, observation of surface morphology and measurements of thickness and surface roughness. Arc generation voltage decreased with increasing Na3PO4 concentration. Color difference of PEO films between edge and inner part disappeared by addition of Na3PO4. It was also observed that size of nodules on PEO film decreased with increasing Na3PO4 concentration. Thickness of PEO films formed on AA2024 increased with increasing Na3PO4 concentration. Whereas, surface roughness of PEO films decreased with increasing Na3PO4 concentration up to 0.05 M of Na3PO4 which is attributed to the deceased size of nodules on the PEO films. However, the surface roughness increased with increasing Na3PO4 concentration more than 0.07 M of Na3PO4 which seems to be due to the formation of non-uniform PEO films with smooth surface and large size pores formed by orange-colored big arcs. The experimental results suggest that added sodium phosphate less than 0.2 M in an alkaline silicate solution can contribute to the formation of relatively thick and uniform thickness of PEO films under arc generation voltage lower than 300 V.

• Journal of the Korean Wood Science and Technology
• /
• 제50권4호
• /
• pp.246-255
• /
• 2022

The need for non-destructive testing and evaluation of Korean traditional wooden buildings is increasing because of their widespread deterioration. Among all types of deterioration, termite damage in wooden columns is the most difficult to detect with the naked eye because it starts inside the wood, and the initial deterioration is small. X-ray computed tomography (CT) is the best technology to investigate the inner state of wood that has less damage, but applying it to wooden columns between walls is challenging. Therefore, the feasibility of tomosynthesis, which is a method to reconstruct a coronal section of a subject with a few X-ray projections from a limited angle of rotation, was studied as an alternative to CT. Pine (P. densiflora) with three artificial holes was prepared as a specimen to evaluate the quality of reconstructed tomosynthesis images according to the different number of projections. The quality of the tomosynthesis images in the in-focus plane was evaluated using the contrast-to-noise ratios, while a vertical resolution between the images was assessed by determining the artificial spread function. The quality of the tomosynthesis image in the in-focus plane increased as the number of projections increased and then remained constant as the number of projections reached 21 or over. In the case of vertical resolution, there was no significant difference when 21 projections or more were used to reconstruct the images. A distinct difference between coronal section images was found when the distance was more than 10 mm from one plane to another plane.

• 한국발생생물학회지:발생과생식
• /
• 제25권4호
• /
• pp.257-268
• /
• 2021

Phthalates and their metabolites are well-known endocrine disrupting chemicals. Di-(2-ethylhexyl) phthalate (DEHP) has been widely used in industry and the exposing possibility to adult is high. In this study, DEHP was treated (133 ㎍/L and 1,330 ㎍/L in drinking water) according to the OECD test guideline 443 to mature female mice and their adrenal gland were examined for histological characteristics and steroidogenic gene expression. The wet weight of the adrenal gland was increased in all administrated groups compared to control. The diameter of zona fasciculata (ZF) was increased by DEHP in both outer ZF and inner ZF but there was no difference in morphology of the cells and arrangements into zona between groups. In addition, the arrangement of extracellular matrix was not different between control and DEHP groups. CYP11B1 was mainly localized at ZF and the intensity was not different between groups. DAX1 was localized in zona glomerulosa (ZG) and ZF, and its expression levels were decreased by DEHP administration. Its level was lower in DEHP133 group than DEHP1330 group. On the other hand, CYP17A1 was localized in ZG of DEHP1330 group. These results suggest that chronic low-dose DEHP exposing may modify the microstructure and function of the adrenal cortical cortex.

• 한국포장학회지
• /
• 제28권2호
• /
• pp.143-149
• /
• 2022

PCS needs to freely switch AC and DC to connect the battery, external AC loads and renewable energy in both directions for energy efficiency. Whenever converting happens, power loss inevitably occurs. Minimization of the power loss to save electricity and convert it for usage is a very critical function in PCS. PCS plays an important role in the ESS(Energy Storage System) but the importance of stabilizing semiconductors on PCB(Printed Circuit Board) should be empathized with a risk of failure such as a fire explosion. In this study, the temperature variation inside PCS was reviewed by cooling fan on top of PCS, and the vibration characteristics of PCS were analyzed during truck transportation for reliability of the product. In most cases, a cooling fan is mounted to control the inner temperature at the upper part of the PCS and components generating the heat placed on the internal aluminum cooling plate to apply the primary cooling and the secondary cooling system with inlet fans for the external air. Results of CFD showed slightly lack of circulating capacity but simulated temperatures were durable for components. The resonance points of PCS were various due to the complexity of components. Although they were less than 40 Hz which mostly occurs breakage, it was analyzed that the vibration displacement in the resonance frequency band was very insufficient. As a result of random-vibration simulation, the lower part was analyzed as the stress-concentrated point but no breakage was shown. The steel sheet could be stable for now, but for long-term domestic transportation, structural coupling may occur due to accumulation of fatigue strength. After the test completed, output voltage of the product had lost so that extra packaging such as bubble wrap should be considered.

• 수산해양기술연구
• /
• 제59권3호
• /
• pp.189-195
• /
• 2023

This study quantitatively evaluated size selectivity for three netting shapes (T0; regular, T45, T90) and hanging ratio (35%, 70%) of T0 netting used for trawl codend. The size selectivity experiment was performed in a tank using a cube experimental model with a length of 50 cm on one side and 389 experimental individuals, jack mackerel (Trachurus japonicus). In the selectivity analysis, a selectivity curve was created based on the selection ratio using a logistic function, and the 25%, 50%, and 70% selection length and selection range (SR) were obtained. The T0 netting was 19.54 cm when the 50% selective length, which is a selectivity evaluation index, had a hanging ratio of 35%, a selection range of 0.51 cm, and 22.70 cm and 3.08 cm for the hanging ratio of 70%. The T45 netting was 24.34 cm and 2.13 cm, and the T90 netting was 23.51 cm and 2.84 cm. The results of the T45 netting and the T90 netting are similar, and the 50% selection length and selection range were relatively larger than the T0 netting. There was a significant difference in the correlation between the circumference of the inner circle of the mesh by the shape of the netting and the body girth of the experimental individual (Pearson test, r = 0.86, p < 0.05). There was no significant difference in the correlation between the selection ratio by the T0 netting, T45 netting, and T90 netting with a 70% hanging ratio (one-way ANOVA, p > 0.05). The results of this study showed that selectivity such as T45 netting and T90 netting appeared when the hanging ratio, which maximizes the area of T0 netting, was maintained at 70%.

• Journal of Animal Science and Technology
• /
• 제65권2호
• /
• pp.401-411
• /
• 2023

Many studies have been conducted to improve technology for semen cryopreservation in pigs. However, computer-assisted analysis of sperm motility and morphology is insufficient to predict the molecular function of frozen-thawed semen. More accurate expression patterns of boar sperm proteins may be derived using the isobaric tags for relative and absolute quantification (iTRAQ) technique. In this study, the iTRAQ-labeling system was coupled with liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis to identify differentially expressed CM10-fractionated proteins between fresh and frozen-thawed boar semen. A total of 76 protein types were identified to be differentially expressed, among which 9 and 67 proteins showed higher and lower expression in frozen-thawed than in fresh sperm samples, respectively. The classified functions of these proteins included oxidative phosphorylation, mitochondrial inner membrane and matrix, and pyruvate metabolic processes, which are involved in adenosine triphosphate (ATP) synthesis; and sperm flagellum and motile cilium, which are involved in sperm tail structure. These results suggest a possible network of biomarkers associated with survival after the cryopreservation of Duroc boar semen.

• 한국음향학회지
• /
• 제29권2호
• /
• pp.118-124
• /
• 2010

본 논문에서는 차량 구동라인의 굽힘 진동을 저감시키기 위해 사용되는 동흡진기의 설계 파라미터에 대한 최적설계를 수행하였다. 정확한 동적 응답특성을 얻기 위해 구동라인을 구성하는 추진축의 진동해석으로부터 추출된 유연성 데이터를 구동라인 동역학 모델에 적용하여 유연체 구동라인을 만들었다. 동흡진기의 내부 튜브 질량, 고무 강성계수 및 고무 감쇠계수를 최적화를 위한 설계 파라미터로 선택하였다. 구동라인의 수직 가속도를 최소화시키기 위해 중심합성 실험계획법의 3-요인, 2-수준 실험을 15회 수행하여 목적함수에 대한 2차 회귀방정식을 만들었으며, 최적화 프로그램을 이용하여 동흡진기 설계 파라미터들을 결정하였다. 최적화된 동흡진기를 장착한 차량 모델은 초기 모델에 비해 구동라인의 수직 가속도 피크값을 17.1% 감소시켰다.

• 대한한의학원전학회지
• /
• 제3권
• /
• pp.399-443
• /
• 1989

In this thesis, I intend to study the translational and clinical interpretation through the syndrom of "Pyong-Yeol-Byong", and reached the following conclusions. 1. Eum-Yang-Kyo (陰陽交)' 1) Meaning: "Eum" means "Essential and vital energy" "Yang" means "Evil factor affecting health" and "Kyo" means "cross-struggle." 2) Location of disease: Heat evil enter Hyeol-Bun (血分) 3) Pathogenesis: Heat evil invade Eum-Bun (陰分) and struggles with Health energy, therefore Eum-Chung (陰精) is exhausted and Heat-evil doesn't disapper, it damage Eum and exhaust fluid. Reach fever, rapid pulse raving and unable to take meal, not controled by sweating and sceach death. 4) Particularity of Syndrome: Heat enter Hyol-Bun, and Evil factor is enough and Health energy is insufficient, so that reveal the symptoms of high fever, delirium with coma, unable to take meals. 5) Therapy: It clears Gi-Bun heat evil (氣分熱邪) by Gypsum, Rhizoma Anemarrhenae, Flos Lonicerae, Fructus Forsythiae, Fructus Gardeniae, Radix Scutellanae Rhizoma Coptidis, and cools Blood by Cornu Rhinoceri Asiatici, Radix Rehmanniae, Cortex Moutan Radicis, Dae-Chung-Yob (大靑葉) Radix Arnebiae Seu Lithospermi. 2. Poong Gweol (風厥) 1) Meaning: Poong means wind-evil, Gweol means reversing up. 2) Location of disease: Disease complexes with TaeYang (太陽) in outer part, and with So-Eum (少陰) in inner part. 3) Pathogenesis: Tae-Yang-Gyeong (太陽經) accept wind-evil and So-Eum-Gyeong (少陽經) Kidney Energy reverse up so that fidgetiness not resolves by sweating. 4) Particularity of Syndrome: There are outer symptoms of fever, hydrosis with inner symptoms of fidgetinessis. 5) Therapy: Reduce Jok-Tae-Yang (足太陽) and Supply Jok-So-Eum (足少陰) by accupuncture, so cure Poong Gweol and make balance between Yeong (營) and Wi (衛). 3. Scrofula coused by wind-evil (勞風) 1) Meaning: It means accepting wind evil rest less. 2) Location of Disease: It locates lung 3) Pathogenesis: Because of accepting wind-evil restless, he take scrofula with damaging lung. 4) Particularity of disease: It is lung disease of aversion to wind and shiver, nape-stiffiness, dim eyesight, cough, disphea, vomitting sputum, if one camnot vomit sputum, he died by damage of lung. 5) Therapy: The period of therapy is different by age or strength of health energy, so I think must prevent Eum deficiency and clear fever no reduced in lung. 4. Shin-Poong (腎風) 1) Meaning: It means taking edema by accepting wind-evil, because the kidney controls water. 2) Location of Disease: It is that wind-evil envade kidney. 3) Pathogenesis : Water evil of kidney with wind-heat rises up to face, reach edema, puffines s of the lower eyelid, floating pulse, bombus, yellowish urine, hydrosis and hand-heating, drymouth and excessive thirsty, walkless by heaviness, menstrual disfunction, restless and unable to take meals, unable to lie flat, heavy cough if lie flat, and accepting wind-evil by deficiency of kidney function, so the function of dredging the water passage is not smooth, symptom of water and symptom of wind reveal together. 4) Therapy: Remove wind-heat, promote diuresis to eliminate tile wetness-evil, supplement the dificiency of kidney's Eum. Finally, we can know that later Fever Disease Medicime (溫病學) is affected to the theory of "Pyong Yeol Byong" in 33th Chapter of SoMoon (素問).

• 한국광물학회지
• /
• 제17권3호
• /
• pp.209-220
• /
• 2004

구리 흡착 실험과 MINTEQA2 및 FITEQL3.2 컴퓨터 프로그램을 이용하여 고성군 판곡리에서 산출되는 황토 현탁액의 구리 흡착 특성을 연구하였다 구리 흡착 실험은 pH, 구리 용액의 양, 전해질의 이온 세기를 변화시키면서 실시하였고, 구리의 농도는 유도결합플라즈마분광분석기를 사용하여 분석하였다. 첨가하는 구리 이온의 양과 pH가 증가할수록 흡착되는 구리 이온의 양도 증가한다. 특히 pH가 5.5에서 6.5로 변할 경우 급격한 흡착률의 증가가 있으며, pH 7.5에서 거의 100% 흡착된다. 배경 전해질의 이온 세기에 영향을 받지 않는 것으로 보아 구리 이온은 황토 표면과 내부권 복합체(inner-sphere complex)로써 아주 강한 화학적 결합을 하고 있는 것으로 판단할 수 있다. MINTEQA2 프로그램을 이용하여 구리의 화학종 분포를 계산한 결과, pH가 증가함에 따라 $Cu^{2+}$ 의 농도는 점점 감소하고 $Cu(OH)_2$ 농도는 점점 증가한다. FITEQL3.2 프로그램을 이용하여 황토의 표면을 규산염 광물 자리와 산화염 광물 자리로 나눈 two sites-three pKas 모델을 적용하여 흡착 양상을 모델링한 결과, 구리 용액의 부피가 2～6 mL인 경우 구리 흡착 평형 상수 값을 도출할 수 있었다. 철산화염 광물 반응 자리에 흡착되는 구리의 앙은 pH 4.5～6.5 범위에서 급격한 흡착 양상을 보이다가 그 이상 pH에서는 흡착되는 양이 조금씩 밖에 증가하지 않는다. 규산염 광물 반응 자리에 흡착되는 구리의 양은 구리 용액의 양이 적을 때는 미약하다가 구리 용액의 양이 커질 경우 그 양이 많아진다. 침전에 의하여 제거되는 구리의 양은 광물 표면 자리에 흡착되는 양과 비교하면 아주 적다. 구리 이온에 대한 흡착 친화도는 규산염 광물보다는 철산화염 광물이 더 큰 것으로 판단된다.