• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.612-615
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• 2009

We need to control the growth orientation of CNTs on a substrate for applications to various electric devices. Generally, the flow direction of feed gases and electric field between two electrode affect to growth orientations of CNTs. In this paper, we varied tilt degrees $(0^{\circ},\;20^{\circ},\;35^{\circ},\;50^{\circ},\;65^{\circ},\;90^{\circ})$ of substrates on a cathode and DC bias voltages (0, 500, 700 V) applied between two electrodes in order to change growth orientations of CNTs. We confirmed that tilt degrees of the substrate and variation of DC bias voltages affected to the shape and orientation of the grown CNTs on the substrate.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.8
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• pp.81-87
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• 1993

The growth thickness uniformity of epitaxial layers deposited using a moiecular beam epitaxy system is calculated from the arrangement of molecular beam source and the substrate and the geometric dimensions of the crucible in order to predict the optimum design conditions of the prototype MBE system. The thickness uniformity better than 5% over a 3-inch wafer can be obtained by keeping the distance between the substrate and the crucible's orifice longer than 20cm, the tapering angle of the crucible larger than 6$^{\circ}$, and the angle between the normal to the substrate at the center and the crucible axis as larger as possible. In addition, the growth yield decreases to below 51% as the distance between the substrate and the orifice becomes longer than 25cm.

• Carbon letters
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• v.10 no.3
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• pp.230-233
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• 2009

In this study, a low temperature growth of high-quality carbon nanotubes on glass substrate using a local surface heating without heating damage to substrate was tried and characterized. The local joule heating was induced to only Ni/Ti metal film on glass substrate by applying voltage to the film. It was estimated that local surface joule heating method could heat the metal surface locally up to around $1200^{\circ}C$ by voltage control. We could successfully obtain high-quality carbon nanotubes grown at $300^{\circ}C$ by applying 125 V for joule heating as same as carbon nanotubes grown at $900^{\circ}C$.

• Carbon letters
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• v.6 no.2
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• pp.79-85
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• 2005

The work reported in this paper relates to preparation and characterization of carbon nanomaterials by CVD method on different substrates by decomposition of certain hydrocarbons at 550-$800^{\circ}C$ using a horizontal quartz tube reactor. Monometallic and bimetallic catalyst system of iron and nickel were used for the preparation of different carbon nanomaterials. The influence of various parameters such as substrate/catalyst preparation parameters, the nature of substrate, catalyst concentration, reaction time and temperature on the growth, yield and alignment of carbon nanotubes has been studied. The characterization of carbon nanomaterials has been carried out using SEM, TEM and TGA. The carbon nanomaterials developed were vertically aligned on a large area of flat quartz substrate.

• Journal of Surface Science and Engineering
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• v.46 no.4
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• pp.145-152
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• 2013

The growth behavior of nanocrystalline diamond (NCD) film has been studied for three different substrates, i.e. bare Si wafer, 1 ${\mu}m$ thick W and Ti films deposited on Si wafer by DC sputter. The surface roughness values of the substrates measured by AFM were Si < W < Ti. After ultrasonic seeding treatment using nanometer sized diamond powder, surface roughness remained as Si < W < Ti. The contact angles of the substrates were Si ($56^{\circ}$) > W ($31^{\circ}$) > Ti ($0^{\circ}$). During deposition in the microwave plasma CVD system, NCD particles were formed and evolved to film. For the first 0.5h, the values of NCD particle density were measured as Si < W < Ti. Since the energy barrier for heterogeneous nucleation is proportional to the contact angle of the substrate, the initial nucleus or particle densities are believed to be Si < W < Ti. Meanwhile, the NCD growth rate up to 2 h was W > Si > Ti. In the case of W substrate, NCD particles were coalesced and evolved to the film in the short time of 0.5 h, which could be attributed to the fact that the diffusion of carbon species on W substrate was fast. The slower diffusion of carbon on Si substrate is believed to be the reason for slower film growth than on W substrate. The surface of Ti substrate was observed as a vertically aligned needle shape. The NCD particle formed on the top of a Ti needle should be coalesced with the particle on the nearby needle by carbon diffusion. In this case, the diffusion length is longer than that of Si or W substrate which shows a relatively flat surface. This results in a slow growth rate of NCD on Ti substrate. As deposition time is prolonged, NCD particles grow with carbon species attached from the plasma and coalesce with nearby particles, leaving many voids in NCD/Ti interface. The low adhesion of NCD films on Ti substrate is related to the void structure of NCD/Ti interface.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1150-1153
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• 2003

Carbon nanofilaments were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The structures of carbon nanofilaments were identified as carbon nanotubes or carbon nanofibers. The formation of bamboo-like carbon nanotubes was initiated by the application of the bias voltage during the plasma reaction. The growth kinetics of bamboo-like carbon nanotubes increased with increasing the bias voltage. The growth direction of bamboo-like carbon nanotubes was vertical to the substrate.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.277-286
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• 2008

This paper deals with the theoretical derivation of the modified Haldane model of the substrate inhibition in the microbial growth processes. Based on the biological concepts of substrate-receptor complex working mechanisms, a new microbial kinetics of N-fold multiplex substrate inhibition and its generalization has been considered theoretically, which is natural expansion of the simple substrate inhibition mechanism in the enzyme reaction. As a result, the modified Haldane model of the substrate inhibition turns out to be a well-designed four-parameter kinetic model with a biological constant of the total substrate inhibition concentration.

• Journal of Environmental Science International
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• v.30 no.8
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• pp.605-612
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• 2021

Supply electrical conductivity (EC) concentration of the nutrition solution is an important factor in the absorption of nutrients by plants and the management of the root zone, as it can control the vegetative/reproductive growth of a plant. Paprika usually undergoes its reproductive and vegetative growth simultaneously. Therefore, ensuring proper growth of the plant leads to increased yield of paprika. In this study, growth characteristics of paprika were examined according to the EC concentration of a coir and a rockwool substrate. The supply EC was 1.0, 2.0, and 4.0 mS·cm^-1 applied at the initial stages of the growth using the rockwool (commonly used by paprika farmers) and the coir substrate with a chip and dust ratio of 50:50 and 70:30. For up to 16 weeks of paprika growth, EC concentrations of 1.0 and 2.0 mS·cm^-1 were found to have a greater effect on the growth than EC at 4.0 mS·cm^-1. The normality (marketable) rate of fruit, the soluble solid content, and paprika growth showed that the coir was generally better than the rockwool regardless of the supply EC concentration. The values of the yield per plant at an EC concentration of 4.0 mS·cm^-1 was mostly similar at 1.6 kg (coir 50:50), 1.5 kg (coir 70:30) and 1.5 kg (rockwool), but the yield of the rockwool was 88%, which was lower than 98% and 94% yield of the coir substrate. Therefore, this concludes that coir substrate is more effective than rockwool at improving paprika productivity. The results also suggest that the use of coir substrate for paprika has many benefits in terms of reducing production costs and preventing environmental destruction during post-processing.

• Archives of Pharmacal Research
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• v.27 no.4
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• pp.361-370
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• 2004

The discovery of insulin receptor substrate (IRS) proteins and their role to link cell surface receptors to the intracellular signaling cascades is a key step to understanding insulin and insulin-like growth factor (IGF) action. Moreover, IRS-proteins coordinate signals from the insulin and IGF receptor tyrosine kinases with those generated by proinflammatory cytokines and nutrients. The IRS2-branch of the insulin/IGF signaling cascade has an important role in both peripheral insulin response and pancreatic $\beta$-cell growth and function. Dysregulation of IRS2 signaling in mice causes the failure of compensatory hyperinsulinemia during peripheral insulin resistance. IRS protein signaling is down regulated by serine phosphorylation or protea-some-mediated degradation, which might be an important mechanism of insulin resistance during acute injury and infection, or chronic stress associated with aging or obesity. Under-standing the regulation and signaling by IRS1 and IRS2 in cell growth, metabolism and survival will reveal new strategies to prevent or cure diabetes and other metabolic diseases.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.5
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• pp.215-219
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• 2004

ZnO epitaxial films have been grown on a (0001)sapphire substrate by RF magnetron sputtering. The single crystalline ZnO films were grown at the condition of growth rate of about 0.1~0.2 $\mu\textrm{m}$/hr and the substrate temperature of $600^{\circ}C$. The film thickness was about 400~500 nm. The thin film quality and micro-structure have been evaluated by XRD and TEM observation.