• Journal of applied mathematics & informatics
• /
• v.8 no.2
• /
• pp.345-360
• /
• 2001

Affine invariant sufficient conditions are given for two local convergence theorems involving inexact Newton-like methods. The first uses conditions on the first Frechet-derivative whereas the second theorem employs hypotheses on the mth(m≥2 an integer). Radius of convergence as well as rate of convergence results are derived. Results involving superlinear convergence and known to be true for inexact Newton methods are extended here. Moreover, we show that under hypotheses on the mth Frechet-derivative our radius of convergence can sometimes be larger than the corresponding one in [10]. This allows a wider choice for the initial guess. A numerical example is also provided to show that our radius of convergence is larger than the one in [10].

• Journal of applied mathematics & informatics
• /
• v.6 no.2
• /
• pp.393-406
• /
• 1999

Affine invariant sufficient conditions are given for two local convergence theorems involving inexact Newton-like methods. The first uses conditions on the first Frechet-derivative whereas the second theorem employs hypotheses on the second. Radius of con-vergence as well as rate of convergence results are derived. Results involving superlinear convergence and known to be true for inexact Newton methods are extended here. Moreover we show that under hypotheses on the second Frechet-derivation our radius of convergence results are derived. Results involving superlinear convergence and known to be true or inexact Newton methods are extended here. Moreover we show that under hypotheses on the second Frechet-derivative our radius of conver-gence is larger than the corresponding one in [10]. This allows a wider choice for the initial guess. A numerical example is also pro-vided to show that our radius of convergence is larger then the one in [10].

• YAKHAK HOEJI
• /
• v.23 no.2
• /
• pp.63-68
• /
• 1979

Biopbysical investigation has been carried out for the interaction of riboflavin tetraacetate and an orotic acid derivative to know the binding mechanism between dihydroorotate dehydrogenase and dihydroorotic acid which are concerned with the oxidoreduction in vivo. Infrared and nuclear magnetic resonance spectra were measured for the chloroform solution of riboflavin tetraacetate, orotic acid butyl ester and its same mixture. Orotic acid butyl ester has been found to associate with riboflavin tetraacetate. They form a strong complex with each other. The complex is an 1:2 cyclic hydrogen bonded trimer through the imino and 2-C carbonyl groups of the isoalloxazine ring and the imino groups of the orotic acid derivative.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.45-48
• /
• 2005

Self compacting concrete has the strong point in capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. However, powder type self compacting concrete has the weak point in the heat of hydration, the drying shrinkage and the elastic property of concrete etc. Recently viscosity agent has been developed in order to overcome these weaknesses. In this study, self compacting concrete is made with viscosity agent based on polysaccharide derivative in order to develope the normal strength self compacting concrete. Slump flow, loss of slump flow and setting time are measured for comparison with normal concrete. Compressive strength, freezing and thawing test and carbonation test are conducted on normal and self compacting concrete using viscosity agent. In the experiment, we acquired good results in fresh and hardened self compacting concrete using viscosity agent based on polysaccharide derivative.

• Interaction and multiscale mechanics
• /
• v.2 no.4
• /
• pp.333-352
• /
• 2009

We introduce a radial basis collocation method to solve axially moving beam problems which involve $2^{nd}$ order differentiation in time and $4^{th}$ order differentiation in space. The discrete equation is constructed based on the strong form of the governing equation. The employment of multiquadrics radial basis function allows approximation of higher order derivatives in the strong form. Unlike the other approximation functions used in the meshfree methods, such as the moving least-squares approximation, $4^{th}$ order derivative of multiquadrics radial basis function is straightforward. We also show that the standard weighted boundary collocation approach for imposition of boundary conditions in static problems yields significant errors in the transient problems. This inaccuracy in dynamic problems can be corrected by a statically condensed semi-discrete equation resulting from an exact imposition of boundary conditions. The effectiveness of this approach is examined in the numerical examples.

• Natural Product Sciences
• /
• v.20 no.1
• /
• pp.22-28
• /
• 2014

A new natural product, tetrastigmol A (1), and several known compounds as flavonoids (2 - 8), steroids (9 - 10), bergenin and its derivative (11 - 12), stilbens (13 - 15), lignan (16), benzenecarboxylic derivative (17) and two norisoprenoid (18 - 19) were isolated from the stem of Tetrastigma erubescens Planch. (Vitateae). Their structures were determined on the basis of NMR spectroscopic data. This is the first report on chemical constituents of this plant. Compounds 1, 6 - 8 and 12 - 15 showed strong antioxidant activity using two methods including DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging and lipid peroxidation inhibitory assays.

• Journal of the Korean Magnetic Resonance Society
• /
• v.12 no.1
• /
• pp.33-39
• /
• 2008

Four sesterterpenoids were isolated from AMPK activity-guided fraction of marine sponge Sarcotragus species. Their planar structures were determined from combination of extensive 1D and 2D NMR experiments and MS data, and the configuration at the chiral centers were assigned by comparison with the $^1H$ and $^{13}C$ chemical shifts of the known compounds. Among four compounds, compound 2 was found to be a new sarcotrine derivative. Though not strong, compounds 1-4 moderately showed AMPK activation effect on L6 myoblast cell through Western Blot analysis.

• Journal of Acupuncture Research
• /
• v.19 no.3
• /
• pp.126-137
• /
• 2002

Objective : There is accumulating data that cardiovascular diseases, including hypertension, cerebro-vascular accident, coronary heart disease, relate to atherosclerotic changes. Increased serum levels of lipids could play a role in these circumstances. the SDPTG(the second derivative of photoplethysmogram waveform) is noninvasive methods for evaluating the pulse wave and is correlated with age and other risk factors for atherosclerosis. Methods : To study the effects of serum lipid levels on the SDPTG in the middle-age adults, data on serum lipid levels and the SDPTG were collected in 80 healthy middle age with varying serum lipid concentrations. Biological vascular age was assessed using the SDPTG. the SDPTG consists of an a, b, c, and d wave in systole and an e wave in diastole; an SDPTG aging index(Al) was calculated as (b-c-d-e)/a. Results : Serum triglyceride, total cholesterol, total lipid, phospholipid, HDL cholesterol levels were respectively and significantly correlated with SDPTG Al. Serum lipid levels and blood pressure are age-dependent and the SDPTG is blood pressure-dependent. Restricting analysis to age and blood pressure yield strong positive correlations between serum triglyceride, total lipid levels and SDPTG Al, but no correlations between serum total cholesterol, phospholipid levels and SDPTG Al. Conclusion : The results of this study suggest that preventive acupuncture programs or herbal medications for reducing serum lipid, especially triglyceride, levels in middle-age should include a evaluation of biological vascular aging with the second derivative of photoplethysmogram waveform.

• Horticultural Science & Technology
• /
• v.28 no.4
• /
• pp.656-663
• /
• 2010

In order to improve the consumer acceptance of fragrant yellow hybrids of $Phalaenopsis$ ($Phal.$), crosses between yellow hybrid varieties were made and the obtained hybrids were investigated for horticultural characteristics as well as difference in fragrance patterns. Cross combination of $Phal.$ Brother lawrence and $Phal.$ Brother saragold yielded good seedling population of 500 plants. Segregation was noticed in color density, spot and stripe patterns on yellow color base of petal and also in fragrance. Six lines with multi-branch on flower stalk and strong fragrance flower were finally selected. Volatile fragrance components were compared among $Phal.$ Brother lawrence, $Phal.$ Brother saragold and their hybrids by GC/SAW electronic nose. In the derivative pattern of chromatogram and polar derivative pattern of fragrance, similar dominant peaks appeared on retention time 7-9 s and some hybrid lines had two strong peaks on retention time 20-25 s, respectively. Also in polar frequency pattern of fragrance obtained by $VaporPrint^{TM}$ image analysis among parent flowers and hybrids, an identical strong peak near 8 s of retention time was shown. This single fragrance component is considered a key element of fragrance in $Phal.$ Brother lawrence, $Phal.$ Brother saragold and their hybrids. This peak could be used as a marker for the breeding of fragrance in $Phalaenopsis$.

• Korean Journal of Pharmacognosy
• /
• v.23 no.4
• /
• pp.240-247
• /
• 1992

Impatiens balsamina Linne(Balsaminaceae) known as 'BONG SUN HWA' in Korea and has been used for the treatment of scrofulosis, carbunculus and dysenteria etc. Bioassay-guided fractionation of MeOH extract from the whole plants of Impatiens balsamina has afforded a simple naphthoquinone derivative, 2-methoxy-1,4-naphthoquinone. The structure of this compound was established by spectroscopic methods. This compound possessed strong antifungal activity against Candida albicans, AspergiIlus niger, Crytococcus neoformans and Epidermophyton floccusum. The activity of 2-methoxy-1,4-naphthoquinone on E. floccusum $(MIC{\;}:{\;}5.0{\;}{\mu}g/ml)$ was the same potency as that of nystatin. It showed also strong antibacterial activity against gram-positive bacteria Bacillus subtilis as well as gram-negative bacteria Salmonella typhimurium. Although the activity of this compound on gram-negative bacteria was lower than that of gram-positive bacteria.