• 대한화학회지
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• 제61권2호
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• pp.57-64
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• 2017

Monoclinic $VO_2(M)$ nanoparticles codoped with 1.5 at. % W and 2.9 at. % Mg were synthesized by the hydrothermal treatment and post-thermal transformation method of $V_2O_5-H_2C_2O_4-H_2O$ with $Na_2WO_4$ and $Mg(NO_3)_2$. The composite thin film of the W/Mg-codoped $VO_2(M)$ with a commercial acrylic block copolymer was also prepared on PET substrate by wet-coating method. The reversible phase transition characteristics of the codoped $VO_2(M)$ nanoparticles and the composite film were investigated from DSC, resistivity and Vis-NIR transmittance measurements compared with the undoped and Wdoped $VO_2(M)$ samples. Mg-codoping into W-doped $VO_2(M)$ nanoparticles synergistically enhanced the transition characteristics by increasing the sharpness of transition while the transition temperature ($T_c$) lowered by W-doping was maintained. The codoped composite film showed the prominently enhanced NIR switching efficiency compared to only W-doped $VO_2(M)$ film with a lowered $T_c$.

• Journal of Yeungnam Medical Science
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• 제28권2호
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• pp.145-152
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• 2011

Background: To evaluate the changes in the radiation dose and temperature distribution on irradiated egg albumin and nanoparticle ($Fe_3O_4$) powder mixed egg albumin. Methods: A new type of phantom was designed by fabricating a $30{\times}30{\times}30cm$ acryl square inside a $3{\times}3{\times}3cm$ small square and dividing it into two parts. In the control group, only egg albumin was irradiated, and in the test group, 25 nm 20 mg/cc, 25 nm 40 mg/cc, and 1 um 40mg/cc nanoparticles with egg albumin were irradiated. The radiation isodose distributions and temperature changes were then observed. Results: No significant changes were observed in the radiation dose and temperature distribution. Conclusion: The nanoparticles were considered not to have had any effect on the radiation dose and temperature distribution under the experimental conditions. Further studies can be conducted based on the changes in the mixture material.

• Environmental Analysis Health and Toxicology
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• 제25권4호
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• pp.279-286
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• 2010

Objectives : Platinum nanoparticles (PNPs) are potentially useful for sensing, catalysis, and other applications in the biological and medical sciences. However, little is known about PNP toxicity. In this study, adverse effects of PNPs on the postnatal development of mouse pubs were investigated. Methods : PNPs (size: 20 nm) were prepared and orally administered to mice during premating, gestation, and lactation periods (0.25 mg/kg, 0.5 mg/kg, and 1 mg/kg). Maternal and pup toxicity were evaluated. Results : PNPs did not affect blood biochemical parameters or mortality in dams during the experimental period. Histopathological signs were not observed and pup number was not different between the control and treated groups. Deformity and stillbirth were not observed in the pups. However, PNPs increased pup mortality and decreased the infant growth rate during the lactation period. Conclusion : PNPs may have adverse effects to the postnatal development of mouse pups.

• 한국환경보건학회지
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• 제40권4호
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• pp.294-303
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• 2014

Objectives: Excretion and tissue distribution of titanium oxide nanoparticles were evaluated in rats after oral administration. The relation between toxicity and systemic concentration of nanoparaticles was investigated. Methods: Rats were orally treated with titanium oxide nanoparticles (10, 100 mg/kg) for five consecutive days. General toxicity, blood chemistry, and serum biochemical analysis were analyzed. Titanium concentration in liver, kidney, lung, urine and feces were measured and histopathology was performed in these organs. Results: Induction of toxicological parameters was not observed and titanium nanoparticles were excreted via feces. Conclusion: Absorption of titanium oxide nanoparticles via the gastrointestinal tract after oral administration was very poor and systemic concentration of titanium oxide nanoparticles was not elevated. Titanium oxide nanoparticles did not cause toxicities in rats after oral administration.

• 상하수도학회지
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• 제29권1호
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• pp.77-88
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• 2015

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.355-358
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• 2008

We report a method for improving characteristics of AC PDP in this study. This improvement is obtained by spreading MgO nanoparticles on transparent dielectric layer. These nanoparticles are covered with MgO protective layer by electron beam evaporation. MgO nanoparticle has difference in cathodoluminescence stronger than MgO layer by electron beam evaporation. This method worked for reducing statistical delay especially. Efficacy, discharge voltage and luminance were also improved But these improvements has limited lifetime because continuous ion bombardments changed characteristic of MgO surface.

• 한국지하수토양환경학회지:지하수토양환경
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• 제14권6호
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• pp.101-107
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• 2009

카르복시메틸 셀룰로즈(carboxymethyl cellulose, CMC)와 같은 안정화제는 오염된 지하대수층에서 영가철 나노입자의 이동을 촉진할 수 있다. 본 연구에서는 CMC로 개질된 영가철 나노입자의 이동성을 컬럼실험을 통해 조사하였다. CMC로 개질된 100 mg/L 영가철 나노입자는 모래로 이루어진 공극매체에서 이동이 가능하였다. 하지만 비개질된 영가철 나노입자는 제조된 용액에서 쉽게 엉김현상이 나타났고, 모래로 이루어진 공극매체에서 통과하지 못했다. pH가 7일 때 영가철 나노입자 약 80%가 컬럼을 통과하여 흘러나왔다. pH가 5이하로 감소할 때는, 100%의 CMC로 개질 된 영가철 나노입자는 100%가 흘러나왔다. 이온강도세기 실험에서 $Na^+$과 $Ca^{2+}$ 이온의 농도가 증가함에 따라 CMC로 개질된 영가철의 이동성이 다소 감소하는 것으로 나타났다. 점토과 자연유기물(natural organic matter, NOM) 영향 실험에서는, 1과 5%의 점토와 100과 1000 mg/L의 자연유기물질은 CMC로 개질된 영가철 나노입자의 이동성에는 크게 영향을 주지 못하는 것으로 나타났다. 본 실험의 결과로부터 CMC로 개질된 영가철 나노입자는 다양한 이온세기, 자연유기물농도 및 점토함량을 가진 토양내에서도 효과적으로 이동될 것으로 기대된다.

• Advances in materials Research
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• 제3권2호
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• pp.105-116
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• 2014

The microwave dielectric properties of $CeO_2$ nanoparticles (0.5, 1.0 & 1.5wt%) doped $Mg_2TiO_4$ (MTO) ceramics have been investigated at cryogenic temperatures. The XRD patterns of the samples were refined using the full proof program reveal the inverse spinel structure without any secondary phases. The addition of $CeO_2$ nanoparticles lowered the sintering temperature with enhancement in density and grain size as compared to pure MTO ceramics. This is attributed to the higher sintering velocity of the fine particles. Further, the microwave dielectric properties of the MTO ceramics were measured at cryogenic temperatures in the temperature range of 6.5-295 K. It is observed that the loss tangent ($tan{\delta}$) of all the samples increased with temperature. However, the $CeO_2$ nanoparticles doped MTO ceramics manifested lower loss tangents as compared to the pure MTO ceramics. The loss tangents of the pure and MTO ceramics doped with 1.5 wt% of $CeO_2$ nanoparticles measured at 6.5K are found to be $6.6{\times}10^{-5}$ and $5.4{\times}10^{-5}$, respectively. The addition of $CeO_2$ nanoparticles did not cause any changes on the temperature stability of the MTO ceramics at cryogenic temperatures. On the other hand, the temperature coefficient of the permittivity increased with rise in temperature and with the wt% of $CeO_2$ nanoparticles. The obtained lower loss tangent values at cryogenic temperatures can be attributed to the decrease in both intrinsic and extrinsic losses in the MTO ceramics.

• 대한수의학회지
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• 제62권4호
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• pp.30.1-30.6
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• 2022

In the study, zinc oxide nanoparticles (ZNOPs) at concentrations of 20, 40, and 60 mg/kg were tested for their antimicrobial action against the oocysts of Eimeria tenella. The oocysts of E. tenella were isolated from the feces of broilers received at the veterinary hospital in Diwaniyah Province and initially diagnosed by compound optical microscopy. The oocysts were confirmed molecularly by polymerase chain reaction targeting the ITS1 gene with a molecular weight of 409 bp. The results in the first week showed that ZNOP concentrations of 20 and 40 mg/kg possess various activities against E. tenella, while 60 mg/kg was the most effective in reducing excreted oocysts compared to the positive control and amprolium group, along with the appearance of mild symptoms and a mortality rate of 0.8%. In the second week of infection, excreted oocysts and mortality rates generally decreased in all treated groups. A comparison of all groups showed that the 60 mg/kg ZNOP-treated group had a significantly lower number of excreted oocysts, and all birds in this group recovered during the second week of infection. These findings revealed the prospect of using ZNOPs against E. tenella in challenging situations of the appearance of resistance to anticoccidial agents.

• Elastomers and Composites
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• 제58권4호
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• pp.191-200
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• 2023

In this study, MoS₂ nanoparticles were synthesized and analyzed through powder X-ray diffraction, Raman, ultraviolet-visible, and X-ray photoelectron spectroscopies. The surface morphologies of the as-synthesized MoS₂ nanoparticles were investigated through scanning and transmission electron microscopies. The sonocatalytic activity of the MoS₂ nanoparticles toward Orange II removal was evaluated by utilizing a Box-Behnken design for response surface methodology in the experimental design. The sonocatalyst dosage, Orange II dye concentration, and ultrasound treatment time were optimized to be 0.49 g/L, 5 mg/L, and 150 min, respectively. The maximum efficiency of Orange II degradation on MoS₂ nanoparticles was achieved, with a final average value of 82.93%. Further, the results of a kinetics study on sonocatalytic Orange II degradation demonstrated that the process fits well with a pseudo-first-order kinetic model.