• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.396-400
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• 1989

The oxygen index test was carried out to obtain the relative flammability of wood-based materials (plywood, MDF, particleboard) and their oxygen indices. The oxygen index is the minimum concentration of oxygen, expressed as volume percent, in a mixture of oxygen and nitrogen that will just support flaming combustion of a material under the specified laboratory conditions. In this study the oxygen indices were calculated by using the Dixon and Massey's Up and Down method("N" Large method). The obtained results were as follows : 1. The oxygen indices calculated with Up and Down method were 27.9% for plywood, 26.9% for MDF, and 26.2% for particleboard, indicative of plywood being more difficult to burn than MDF and particleboard Lender the same surrounding conditions. 2. The oxygen indices were not affected by the total gas flow rate.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.19-25
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• 2014

Purpose: Integrated PET/MRI has been developed recently has become a lot of help to the point oncologic, neological, cardiological nuclear medicine. By using this PET/MRI, a ${\mu}-map$ is created some special MRI sequence which may be divided parts of the body for attenuation correction. However, because an MRI contrast agent is necessary in order to obtain an more MRI information, we will evaluate to see an effect of SUV on PET image that corrected attenuation by MRI with contrast agent. Materials and Methods: As PET/MRI machine, Biograph mMR (Siemens, Germany) was used. For phantom test, 1mCi $^{18}F-FDG$ was injected in cylinderical uniformity phantom, and then acquire PET data about 10 minutes with VIBE-DIXON, UTE MRI sequence image for attenuation correction. T1 weighted contrast media, 4 cc DOTAREM (GUERBET, FRANCE) was injected in a same phatnom, and then PET data, MRI data were acquired by same methodes. Using this PET, non-contrast MRI and contrast MRI, it was reconstructed attenuation correction PET image, in which we evanuated the difference of SUVs. Additionally, for let a high desity of contrast media, 500 cc 2 plastic bottles were used. We injected $^{18}F-FDG$ with 5 cc DOTAREM in first bottle. At second bottle, only $^{18}F-FDG$ was injected. and then we evaluated a SUVs reconstructed by same methods. For clinical patient study, rectal caner-pancreas cancer patients were selected. we evaluated SUVs of PET image corrected attenuastion by contrast weighted MRI and non-contrast MRI. Results: For a phantom study, although VIBE DIXON MRI signal with contrast media is 433% higher than non-contrast media MRI, the signals intensity of ${\mu}-map$, attenuation corrected PET are same together. In case of high contrast media density, image distortion is appeared on ${\mu}-map$ and PET images. For clinical a patient study, VIBE DIXON MRI signal on lesion portion is increased in 495% by using DOTAREM. But there are no significant differences at ${\mu}-map$, non AC PET, AC-PET image whether using contrast media or not. In case of whole body PET/MRI study, %diff between contras and non contrast MRAC at lung, liver, renal cortex, femoral head, myocardium, bladder, muscle are -4.32%, -2.48%, -8.05%, -3.14%, 2.30%, 1.53%, 6.49% at each other. Conclusion: In integrated PET/MRI, a segmentation ${\mu}-map$ method is used for correcting attenuation of PET signal. although MRI signal for attenuation correciton change by using contrast media, ${\mu}-map$ will not change, and then MRAC PET signal will not change too. Therefore, MRI contrast media dose not affect for attenuation correction PET. As well, not only When we make a flow of PET/MRI protocol, order of PET and MRI sequence dose not matter, but It's possible to compare PET images before and after contrast agent injection.

• Honam Mathematical Journal
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• v.37 no.2
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• pp.245-252
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• 2015

This paper is in continuation of the paper very recently published [New Laplace transforms of Kummer's confluent hypergeometric functions, Math. Comp. Modelling, 55 (2012), 1068-1071]. In this paper, our main objective is to show one can obtain so far unknown Laplace transforms of three rather general cases of generalized hypergeometric function $_2F_2(x)$ by employing generalized Watson's, Dixon's and Whipple's summation theorems for the series $_3F_2$ obtained earlier in a series of three research papers by Lavoie et al. [5, 6, 7]. The results established in this paper may be useful in theoretical physics, engineering and mathematics.

• Journal of the Korean Magnetic Resonance Society
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• v.4 no.1
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• pp.64-73
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• 2000

There are several methods to achieve selective NMR image of differing chemical species with the three most popular methods of Dixon's, CHESS, and SECSI. A major problem common to all chemical shift imaging methods is the uniformity of the static magnetic field and distortions introduced when RF coils are loaded with a conducting specimen. Without magnetic field shimming, these methods cannot be used to acquire selectively image protons in fat and water which are separated by approximately 3.0ppm. Experiments with a phantom, with linewidths of 2.5 to 3.5ppm, were quantitatively evaluated for the three methods and a new chemical shift imaging method. In this study the new chemical shift imaging method (modified CHESS+SECSI technique) which included a selective saturation and refocusing pulse, was developed to determine the ratios of water and fat in different samples.

• Communications of the Korean Mathematical Society
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• v.30 no.3
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• pp.191-200
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• 2015

Generating functions play an important role in the investigation of various useful properties of the sequences which they generate. Exton [13] presented a very general double generating relation involving products of two Laguerre polynomials. Motivated essentially by Exton's derivation [13], the authors aim to show how one can obtain nineteen new generating relations associated with products of two Laguerre polynomials in the form of a single result. We also consider some interesting and potentially useful special cases of our main findings.

• Communications of the Korean Mathematical Society
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• v.29 no.4
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• pp.519-526
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• 2014

A large number of summation and transformation formulas involving (generalized) hypergeometric functions have been developed by many authors. Here we aim at establishing two (presumably) new general hypergeometric transformations. The results are derived by manipulating the involved series in an elementary way with the aid of certain hypergeometric summation theorems obtained earlier by Rakha and Rathie. Relevant connections of certain special cases of our main results with several known identities are also pointed out.

• Honam Mathematical Journal
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• v.36 no.2
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• pp.345-355
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• 2014

The main objective of this paper is to obtain a formula containing eleven interesting results for the reducibility of Kamp$\acute{e}$ de F$\acute{e}$riet function. The results are derived with the help of two general results for the series $_2F_1(2)$ very recently presented by Kim et al. Well known Kummer's second theorem and its contiguous results proved earlier by Rathie and Nagar, and Kim et al. follow special cases of our main findings.

• The Korean Journal of Applied Statistics
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• v.7 no.2
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• pp.1-7
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• 1994

Using a Monte-Carlo simulation technique we evaluate the empiricla distribution of a pseudo-chi-square statistic based on symmetrically Winsorized sum of squares when the population is normally distributed, and search for a chi-square distribution with appropriate degrees of freedom which can be referred to an approximate distribution for Winsorized chi-square.

• Archives of Pharmacal Research
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• v.24 no.4
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• pp.292-296
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• 2001

Three prolyl endopeptidase (PEP) inhibitors were isolated from the methanolic extract of green tea leaves. They were identified as (-)-epigallocatechin gallate, (-)-epicatechin gallate, and (+)-gallucatechin gallate with the $IC_{50}$ values of 1.42${\times}$$10^{-4}$mM, $1.02{\times}10^{-2}$mM, and $1.09{\times}10^{-4}$mM, respectively. They were non-competitive with a substrate in Dixon plots and did not show any significant effects against other serine proteases such as elastase, trypsin, and chymotrypsin, suggesting that they were relatively specific inhibitors against PER The isolated compounds are expected to be useful for preventing and curing of Alzheimer's disease.

• East Asian mathematical journal
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• v.25 no.4
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• pp.481-486
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• 2009

The first object of this note is to show that a summation formula due to Padmanabham for three-variables hypergeometric function $X_8$ introduced by Exton can be proved in a different (from Padmanabham's and his observation) yet, in a sense, conventional method, which has been employed in obtaining a variety of identities associated with hypergeometric series. The second purpose is to point out that one of two seemingly new hypergeometric identities due to Exton was already recorded and the other one is easily derivable from the first one. A corrected and a little more compact form of a general transform involving hypergeometric functions due to Exton is also given.