• Journal of Life Science
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• v.17 no.7 s.87
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• pp.910-914
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• 2007

In order to synthesize new bioactive compounds and contrasting agents, reactions of glycine and glutamic acid as an animo acid with paraformaldehyde and hypophosphorous acid were executed. Products are 3,7-dihydroxy-3,7-dioxoperhydro-1,5,3,7-diazadiphosphocine-1,5-diacetic acid 1 and 3,7-dihydroxy-3,7- dioxoperhydre-1,5,3,7-diazadiphosphocine-1,5-di-(2-glu taric acid) 3. 2-[5-(1,2-Dicarboxyethyl)-3,7-dihydroxy-3,7-dioxo-315.715-[1,5,3,7] diazadiphosphocan-1-yl]-succinic acid 2 by using aspartic acid was not obtained. Esterification of 3,7- dihydroxy-3,7-dioxoperkydro-1,5,3,7-diaza-diphosphocine-1,5-diacetic acid 1 by treatment of methanol, ethanol, and propanol were executed. 3,7-Dihydroxy-3,7-dioxoperhydro-1,5,3,7-diazadiphosphocine-1,5-diacetic acid methyl ester 4, 3.7-dihydroxy-3,7-dioxoperhydro-1,5,3,f-diazadiphosphocine-1.5-diacetic acid ethyl ester 5, and 3,7-dihydroxy-3,7-dioxoperhydro-1,5,3,7-diazadiphosphocine-1,5-diacetic acid propyl ester 6 were respectively synthesized in good yields. Continuously, we will try synthesis of novel compounds and evaluation of biological activity.

• Restorative Dentistry and Endodontics
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• v.33 no.1
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• pp.1-8
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• 2008

The purpose of this study was to evaluate the effect of a new resin monomer, filler size and polishing technique on the surface roughness of composite resin restorations using confocal laser scanning microscopy. By adding new methoxylated Bis-GMA (Bis-M-GMA, 2,2-bis[4-(2-methoxy-3-methacryloyloxy propoxy) phenyl] propane) having low viscosity, the content of TEGDMA might be decreased. Three experimental composite resins were made: EX1 (Bis-M-GMA/TEGDMA = 95/5 wt%, 40 nm nanofillers); EX2 (Bis-M-GMA/TEGDMA = 95/5 wt%, 20 nm nanofillers); EX3 (Bis-GMA/TEGDMA = 70/30 wt%, 40 nm nanofillers). Filtek Z250 was used as a reference. Nine specimens (6 mm in diameter and 2 mm in thickness) for each experimental composite resin and Filtek Z250 were fabricated in a teflon mold and assigned to three groups. In Mylar strip group, specimens were left undisturbed. In Sof-lex group, specimens were ground with #1000 SiC paper and polished with Sof-lex discs. In DiaPolisher group, specimens were ground with #1000 SiC paper and polished with DiaPolisher polishing points. The Ra (Average roughness), Rq (Root mean square roughness), Rv (Valley roughness), Rp (Peak roughness), Rc (2D roughness) and Sc (3D roughness) values were determined using confocal laser scanning microscopy. The data were statistically analyzed by Two-way ANOVA and Tukey multiple comparisons test (p = 0.05). The type of composite resin and polishing technique significantly affected the surface roughness of the composite resin restorations (p < 0.001). EX3 showed the smoothest surface compared to the other composite resins (p < 0.05). Mylar strip resulted in smoother surface than other polishing techniques (p < 0.05). Bis-M-GMA. a new resin monomer having low viscosity, might reduce the amount of diluent, but showed adverse effect on the surface roughness of composite resin restorations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.5
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• pp.1300-1307
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• 1995

The effect of thermal stratification on the turbulent dispersion from a fine cylindrical heat source was experimentally examined in a wind tunnel with and without a strong temperature gradient. A 0.5 mm dia. nichrome wire was used as a line heat source. Turbulent intensities, r.m.s. value of temperature and convective heat fluxes were measured by using a hot-wire and cold-wire combination probe. The results show that the peack value and the spread of the vertical turbulent intensity for the stratified case are far lower than those in the neutral case, which indicates that the stable temperature gradient suppresses the vertical velocity component. All of the third order moments including heat fluxes measured in the stable condition have very small values than those of the neutral case. This nature suggests that the decrease of scalar fluctuations in the stably stratified flow is mainly due to the suppression ofthe turbulent diffusion processes by the stable stratification. A simple gradient model with a composite timescale which has a simple weighted algebraic mean between dynamic and thermal time scale yields reasonably good numerical values in comparison with the experimental data.

• The KIPS Transactions:PartB
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• v.12B no.3 s.99
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• pp.313-322
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• 2005

In order to access digital items in a server via ubiquitous devices, the digital items should be adapted according to the system environment, device characteristics and user preferences. In ubiquitous environment, those device-dependent adaptation requirements are not statically determined and not predictable. Therefore an application specific adaptation mechanism can not be applied to a general digital item adaptation engine. In this paper, we propose an application independent digital item adaptation architecture which has a set of minimal transcoders, transcoding path generator for a required adaptation requirement, and adaptation scheduler. And a CFG based method of finding a sequence of multiple unit transcoders called a transcoding path Is described in detail followed by experimental results.

• Journal of radiological science and technology
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• v.42 no.4
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• pp.285-290
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• 2019

Magnetic resonance imaging is a technique specialized in soft tissue imaging with high contrast resolution without in vivo ionization and has been widely used in various clinical settings. In particular, the recent increase in social stress factors has been used in the diagnosis of pituitary adenoma, the incidence increases rapidly. Recently, due to the development of magnetic resonance imaging, it is possible to diagnose micro pituitary adenoma, but despite the use of contrast medium, there has been a difficulty in diagnosing the pituitary adenoma due to its small size and noise. In order to solve this problem, a proposed method of separating signal components image and noise components image from a measured image is applied, and the improvement of diagnostic efficiency is attempted by removing noise. As a result, it was confirmed that the image quality was improved as a whole by applying SNR for 30 subjects data. It is expected that this study will be useful as a pre-processing method for improving the image quality and developing diagnostic indicators of pituitary adenoma.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.55-60
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• 2009

Stabilization treatment is one of processes for wastes and their components to reduce their toxicity and migration rates to surroundings. Inorganic binders such as calcium hydroxide, blast furnace slag and red mud were tested for their potential applicability to in-situ stabilization of heavy metal contaminated tailings in the abandoned metal mines. Columns(150mm dia. ${\times}$ 450mm length) filled with mixtures of inorganic binders and tailing from the Geumjang mine with various mixing ratios of binders to tailings, 5%, 7% and 9% were applied artificial rainfall tests for 28 days. Effluents from columns filled with calcium hydroxide and tailing showed high pH's of ~12.5 and a increasing trend of concentration in Pb and Zn with a significant decrease in permeability in terms of elapsed days. Those with burning slag and tailing showed pH's of ~8.5 and significantly low concentrations in heavy metals with a stable permeability. In case of red mud, effluents showed significantly low concentrations in heavy metals but a decreased permeability with pH's of ~10.5. Conclusively, this basic study suggests burning furnace slag be a potential stabilizer for effective treatment of heavy metal contaminated mine tailings.

• Journal of ILASS-Korea
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• v.5 no.4
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• pp.40-46
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• 2000

To understand the basic the structure of the spray field and to obtain the initial conditions for computational models for shear coaxial twin-fluid injectors. the atomization characteristics under different flow and geometric conditions were examined. The spray characteristics such as SMD, mean axial and radial velocities, Dia. of droplets and volume flux with a P.D.P.A. Water and nitrogen gas under atmospheric conditions were used as a test fluids. The drops produced by shear coaxial injectors continue to disintegrate along the spray axis and decrease their sizes. SMD was the maximum at the spray center of spray and decreased with increasing radial distance. The results of this parametric study showed that SMD decreased with increasing gas injection velocity as well as with decreasing liquid injection mass flow rate, The relative velocity between gas and liquid flow played a significant role resulted in decreasing SMD and in spreading the spray. Recessing the liquid orifice resulted decreasing SMD and a spreading the spray. Recess of liquid orifice by 5.0mm showed best atomization characteristics in this experiment. Although drop diameter changes, shear coaxial injector sprays had constant velocity and exhibited a high degree of radial symmetry.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1775-1783
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• 2001

For two decades, there has been an active research to enhance the performances of Particle Image Velocimetry (PIV) systems. However, the resulting systems are somewhat very costly, cumbersome and delicate. In this paper, we address the design and some first experimental results of a PIV system belonging to the opposite paradigm. The Miniature PIV or MPIV system feature relatively modest performances, but is considerably smaller (out MPIV could hold in dia. 40 mm$\times$120 mm), cheaper (out MPIV total cost is less than $500) and easy to handle. Potential applications include industrial velocity sensors. The proposed MPIV system uses a one-chip-only CMOS camera with digital output. Only two other chips are needed, one for a buffer memory and one for an interfacing logic that controls the system. Images are transferred to a personal computer (PC or laptop) via its standard parallel port. No extra hardware is required (in particular, no frame grabber board is needed). In our first MPIV prototype presented in this paper, the strobe lighting is generated by a cheap 5 mW laser pointer diode. Experimental results are presented and discussed.

• Korean Journal of Optics and Photonics
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• v.2 no.4
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• pp.179-185
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• 1991

Twyman-Green interferometer is developed for assessment of IR optical system performance. Light source is $CO_2$ gas laser which has 10.6$\mu \textrm m$ wavelength. The light beam is expanded to 2.5 cm dia by Ge lens and splitted by ZnSe parallel plane plate. One of the beams is reflected by refernce mirror which is operated PZT. The fringe will be detected by a pyro-electric vidicon camera and displayed by a CRT monitor. Here, the IR firinge is recorded on the thermal paper. In visible region, the light source is He-Ne laser. The fringe is detected by a CCD camera and displayed by the CRT monitor. The intensity of the fringe is digitized by a image card and processed by a PC. The wavefront aberration function, PSF and OTF are calculated. The results are displayed in 3-D graphs on the monitor or printed out by a line printer.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.387-395
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• 2003

Model tests were conducted to study the behavior of the piled raft foundation system on sands. Especially in this study, the method using the triaxial compression apparatus was devised and used to apply the confining pressure which is considered difficult in the existing model test on the soil. Steel rods (6mm dia.) and aluminum plates (8mm thickness, 50mm dia.) were used to simulate piles and rafts respectively. Jumunjin standard sands were used to ensure the homogeneity of the sample. After the sample with the piled raft model was laid inside the triaxial cell, the confining pressure was applied and then the compressive force was applied. The increase and/or decrease ratio of the bearing capacity, the load distribution ratio between raft and piles and the effect of settlements decrease depending on the confining pressure, the number of piles and the length of piles were analyzed and the bearing capacity and skin friction of the pile was calculated. By the results of these experiments, the bearing capacity increased and the settlement decreased with this piled raft foundation system. Especially the effect was larger with the increase of the number of piles than with the increase of length of piles. Hereafter, the study of the load transfer mechanism of piles under confining pressure would be made possible using these small model tester like triaxial compression apparatus.