• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.29-32
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• 2005

Chemical mechanical polishing is an essential process in the production of copper-based chips. On this work, the stability of hydrogen peroxide ($H_{2}O_{2}$) as an oxidizer of copper CMP slurry has been investigated. $H_{2}O_{2}$ is known as the most common oxidizer in copper CMP slurry. But $H_{2}O_{2}$ is so unstable that its stabilization is needed using as an oxidizer. As adding KOH as a pH buffering agent, stability of $H_{2}O_{2}$ decreased. However, $H_{2}O_{2}$ stability in slurry went up with putting in small amount of BTA as a film forming agent. There was no difference of $H_{2}O_{2}$ stability between pH buffering agents KOH and TMAH at similar pH value. Addition of $H_{2}O_{2}$ in slurry in advance of bead milling led to better stability than adding after bead milling. Adding phosphoric acid resulted in the higher stability. Using alumina C as an abrasive was good at stabilizing for $H_{2}O_{2}$.

• Advances in nano research
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• v.12 no.5
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• pp.489-499
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• 2022

Nanofluids have recently triggered a substantial scientific interest as cooling media. However, their stability is challenging for successful engagement in industrial applications. Different factors, including temperature, nanoparticles and base fluids characteristics, pH, ultrasonic power and frequency, agitation time, and surfactant type and concentration, determine the nanofluid stability regime. Indeed, it is often too complicated and even impossible to accurately find the conditions resulting in a stabilized nanofluid. Furthermore, there are no empirical, semi-empirical, and even intelligent scenarios for anticipating the stability of nanofluids. Therefore, this study introduces a straightforward and reliable intelligent classifier for discriminating among the stability regimes of alumina-water nanofluids based on the Zeta potential margins. In this regard, various intelligent classifiers (i.e., deep learning and multilayer perceptron neural network, decision tree, GoogleNet, and multi-output least squares support vector regression) have been designed, and their classification accuracy was compared. This comparison approved that the multilayer perceptron neural network (MLPNN) with the SoftMax activation function trained by the Bayesian regularization algorithm is the best classifier for the considered task. This intelligent classifier accurately detects the stability regimes of more than 90% of 345 different nanofluid samples. The overall classification accuracy and misclassification percent of 90.1% and 9.9% have been achieved by this model. This research is the first try toward anticipting the stability of water-alumin nanofluids from some easily measured independent variables.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.246-246
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• 2006

Ionic polymer-metal composite (IPMC) soaked with various ionic liquids was prepared by using polystyrene sulfonic acid-grafted poly(vinylidene fluoride-co-hexafluoropropylene) as ion-exchange membrane (IEM). The prepared IPMCs were effectively deformed three times larger and actuated for 300 times longer than those of Nafion with water at the same applied conditions. The experimental results indicated than the increase in the bending capability can be caused by the increase in the improved properties of the IEMs and ionic liquids such as uptake content and ionic conductivity. And air-operating stability of the IPMCs is appreciably governed by various physical and electrochemical properties of soaked solvents in IEMs.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.17-21
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• 2017

BACKGROUND: Castor oil and wormseed extract are important active ingredients for biopesticide, and ricinoleic acid in castor oil and three monoterpenes (ascaridole, carvacrol and p-cymene) in wormseed extract are known bioactive substances. However, their stabilities had not been studied, even though the stability was the core property for estimation of shelf-life of biopesticide. Aimed to investigate the thermal stabilities of the bioactive substances in castor oil and wormseed extracts. METHODS AND RESULTS: The contents of ricinoleic acid and three monoterpenes (ascaridole, carvacrol and p-cymene) were analyzed by gas chromatography (GC). The thermal stabilities of the bioactive substance were measured at $0^{\circ}C$, $23^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$ and $54^{\circ}C$ for 84 d. The half-lives of ricinoleic acid in biopesticides was ranged from 28.9 d to 57.8 d at $30^{\circ}C$, and the stability of pure castor oil were located in the range ($t_{1/2}$=46.2d for Indian product and 27.7 d for Korean product) at the same temperature. The half-lives of the total monoterpenes in biopesticides were ranged from 3.9 d to 27.7 d at $30^{\circ}C$. Among the monoterpenes, the stability ascaridole and p-cymene were decreased in acidic condition. All the bioactive substances showed similar stability on the different thermal conditions. CONCLUSION:The half-lives of most bioactive substance from castor oil and wormseed extracts were less than 100 d. To increase the stability of bioactive substance in biopesticide, stabilizing additives like antioxidant and oxygen remover should be considered to extend of the shelf-life.

• Current Photovoltaic Research
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• v.8 no.4
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• pp.107-113
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• 2020

Here we report the long-term stability of polymer:nonfullerene solar cells which were stored under dark and indoor light condition. The polymer:nonfullerene solar cells were fabricated using bulk heterojunction (BHJ) layers of poly[(2,6-(4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) and 3,9-bis(6-methyl-2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-M). To investigate their long-term stability, the PBDB-T:IT-M solar cells were stored in an argon-filled glove box. One set of the fabricated solar cells was completely covered with an aluminum foil to prevent any effect of light, whereas another set was exposed to indoor light. The solar cells were subjected to a regular performance measurement for 40 weeks. Results revealed that the PBDB-T:IT-M solar cells underwent a gradual decay in performance irrespective of the storage condition. However, the PBDB-T:IT-M solar cells stored under indoor light condition exhibited relatively lower power conversion efficiency (PCE) than those stored under the dark. The inferior stability of the solar cells under indoor light was explained by the noticeably changed optical absorption spectra and dark spot generation, indicative of degradations in the BHJ layers.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.1
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• pp.23-29
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• 2013

LCC (Liquid cadmium cathode) is used for electrowinning in pyroprocessing to recover uranium and transuranic elements simultaneously. It is one of the core technologies in pyroprocessing with higher proliferation resistance than a wet reprocessing because LCC-cell does not separate TRU from uranium. The crucible which holds the LCC is technically important because it should be nonconducting material to prevent deposition of metallic elements on the crucible outer surface. The chemical stability is also crucial factor to choose crucible material due to the strong reactivities of TRU and possible incorporation of Li metal during the operation. In this study, the chemical stabilities of four kinds of representative ceramic materials such as $Al_2O_3$, MgO, $Yl_2O_3$ and BeO were thermodynamically and experimentally evaluated at $500^{\circ}C$ with simulated LCC. The contact angle of LCC on ceramic materials was measured as function of time to predict chemical reactivity. $All_2O_3$ showed poorest chemical stability and the pores in BeO contributed to a decreases in contact angle. MgO and $Y_2O_3$ have superior chemical stability among the materials.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.338-338
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• 2005

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.225-230
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• 2002

Experiments on deactivation kinetics of immobilized lipase enzyme from Candida cyl-indracea were performed in stirred bath reactor using rice bran oil as the substrate and temperature as the deactivation parameter. The data were fitted In first order deactivation model. The effect of temperature on deactivation rate was represented by Arrhenius equation. Theoretical equations were developed based on pseudo-steady state approximation and Michaelis -Menten rate expression to predict the time course of conversion due to enzyme deactivation and apparent half-life of the immobilized enzyme activity in PFR and CSTH under constant feed rate polity for no diffusion limitation and diffusion limitation of first order. Stability of enzyme in these continuous reactors was predicted and factors affecting the stability were analyzed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.258-261
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• 2006

The addition of zeolite particles enhances the stability of mRNA molecules in a cell-free protein synthesis system. When $20{\mu}g/{\mu}L$ of zeolite (Y5.4) is added to a reaction mixture of cell-free protein synthesis, a substantial increase in protein synthesis is observed. The stabilizing effect of zeolite is most dearly observed in an in vitro translation reaction directed by purified mRNA, as opposed to a coupled transcription and translation reaction. Upon the addition of zeolite in the in vitro translation reaction, the life span of the mRNA molecules is substantially extended, leading to an 80% increase in protein synthesis. The effect of zeolite upon the mRNA stability appears be strongly related to the cation exchange (potassium to sodium) reaction. Our results demonstrate the possibility of modifying this biological process using heterogeneous, non-biological substances in a cell-free protein synthesis system.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.199-205
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• 2016

We present the electrochemical performance of electric double layer capacitors (EDLCs) assembled with pyrrolidinium (Pyr)-based ionic liquid electrolytes at 55 ℃. Cations with various alkyl chain lengths were employed in Pyr-based ionic liquids to investigate the effect of cation structure on the cycling stability of EDLCs. The EDLCs exhibited initial specific capacitances ranging from 122.4 to 131.6 F g⁻¹ based on activated carbon material at 55 ℃. Cycling data and XPS results demonstrate that Pyr-based ionic liquid with longer alkyl chain is more effective for enhancing the cycling stability of EDLC by suppressing the reductive decomposition of pyrrolidinium cations during cycling at high temperatures.