• The Journal of Korean Academy of Prosthodontics
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• v.36 no.5
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• pp.701-720
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• 1998

Research advances in dental implantology have led to the development of several different types of materials and it is anticipated that continued research will lead to advanced dental implant materials. Currently used pure titanium has relatively low hardness and strength which may limit its ability to resist functional loads as a dental implant. Ti-6Al-4V also has potential problems such as corrosion resistance. osseointegration properties and neurologic disorder due to aluminium and vanadium, known as highly toxic elements, contained in Ti-6Al-4V. Newly developed titanium based alloys(Ti-20Zr-3Nb-3Ta-0.2Pd-1In, Ti-20Zr-3Nb-3Ta-0.2Pd) which do not contain toxic metallic components were designed by the Korea Institute of Science and Technology (KIST) with alloy design techniques using Zr, Nb, Ta, Pd, and In which are known as non-toxic elements. Biocompatibility and osseointegration properties of these newly designed alloys were evaluated after implantation in rabbit femur for 3 months. The conclusions were as follows : 1. Mechanical properties of the new designed Ti based alloys(Ti-20Zr-3Nb-3Ta-0.2Pd-1In, Ti-20Zr-3Nb-3Ta-0.2Pd) demonstrated close hardness and tensile strength values to Ti-6Al-4V. 2. New desinged experimental alloys showed stable corrosion resistance similar to the pure Ti but better than Ti-6Al-4V. However, the corrosion rate was higher for the new alloys. 3. Cell culture test showed that the new alloys have similar cell response compared with pure Ti and Ti-6Al-4V with no cell adverse reaction. 4. New designed alloys showed similar bone-metal contact ratio and osseointegration properties compared to pure Ti and Ti-6Al-4V after 3 months implantation in rabbit femur. 5. Four different surface treatments of the metals did not show any statistical difference of the cell growth and bone-metal contact ratio.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.947-955
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• 2011

The complexes [Pd(bpy)(Hex-dtc)]$NO_3$ and [Pt(bpy)(Hex-dtc)]$NO_3$ (bpy is 2,2'-bipyridine and Hex-dtc is hexyldithiocarbamato ligands) were synthesized and characterized by elemental analysis and spectroscopic studies. The cytotoxicity assay of the complexes has been performed on chronic myelogenous leukemia cell line, K562, at micromolar concentration. Both complexes showed cytotoxic activity far better than that of cisplatin under the same experimental conditions. The binding parameters of the complexes with calf thymus DNA (CT-DNA) was investigated using UV-visible and fluorescence techniques. They show the ability of cooperatively intercalating in CT-DNA. Gel filtration studies demonstrated that platinum complex could cleave the DNA. In the interaction studies between the Pd(II) and Pt(II) complexes with CT-DNA, several binding and thermodynamic parameters have been determined, which may provide deeper insights into the mechanism of action of these types of complexes with nucleic acids.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.675-682
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• 2005

Al containing mesoporous molecular sieve (Al-MMS) was synthesized by hydrolysis of $H_2SiF_6$ and $Al(NO_3)_3{\cdot}9H_2O$. The material obtained was characterized by XRD, $N_2$-physisorption. The specific surface area was $981m^2/g$, and the average pore size was uniformity $39{\AA}$. It was confirmed that the acidity of Al-MMS was milder than that of zeolite Y based on the results of $NH_3$-TPD. Active materials, Pt and Pd, were loaded on Al-MMS in order to examine the feasibility of using Al-MMS as a catalyst support in the hydrogenation of aromatic compounds included in the residue oil of a naphtha cracker. The hydrogenation activity of PtPd/Al-MMS has been studied by following the kinetics of the hydrogenation of naphthalene, and by comparing the kinetic parameters obtained with Pt and Pd catalysts supported on the other mesoporous material support and commercial conventional support materials. PtPd/Al-MMS catalyst shows the highest activity of hydrogenation and sulfur resistance. The high activity of PtPd/Al-MMS was confirmed again in the hydrogenation of PGO (pyrolized gas oil), which is residue oil obtained from a naphtha cracker. Therefore, PtPd/Al-MMS can be applied to the hydrogenation of aromatic compounds included in the residue oil of a commercial naphtha cracker commericially.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.59-63
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• 2009

Purpose: To investigate the near horizontal heterophoria of the college students in their twenties on north Kyonggi Province. Methods: The all subjects had not experienced any ocular surgery and have no disease and their mean age is 22.9. As 122 subjects, they are 50 emmetropes and 72 ametropes. The ametropes are all myopia. After distance visual acuity correction with subjective and objective refraction test, evaluated their horizontal heterophoria with red maddox rod. Results: In maddox rod test, the subjects consist of orthophoria 4.9%, esophoria 9.8% and exophoria 85.3%. In the emmetropes orthophoria is 8%, esophoria is also 8% and exophoria is 84%. In the ametropes orthophoria is 2.8%, esophoria is 11.1% and exophoria is 86.1%. The mean size of horizontal heterophoria is esophoria 3.59PD (prism diopter), exophoria 7.04PD and in the emmetropes esophoria is 3.25PD, exophoria is 6.60PD. In the ametropes esophoria is 3.75PD and exophoria is 7.34PD. Conclusions: In the emmetropoes the orthophoria is more than in the ametropes and the esophoria and exophoria is more in the ametropes. But the differences between the heterophoria and emmetropia or ametropia were not significant (p>0.05). The mean size of heterophoria is higher in the ametropes than in the emmetropoes. The distribution range of heterophoria is wider in the male subjects than the female subjects.

• Journal of the Korean institute of surface engineering
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• v.34 no.6
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• pp.545-552
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• 2001

Effect of ultrasonic agitation on Pd catalyst treatment was studied in metallization of ceramic boards by Cu electroless plating method.96% $Al_{2}$$O_{3}$ ceramic boards were used as substrate. In this study, the ultrasonic frequency of 28kHz was applied. In Pd catalyst, high density Pd nuclei of small size were formed during ultrasonic agitation. Density of Pd was more improved when using of ultrasonic then no stirring. In electroless plating, plating rate was in the range of 0.6~1.8$\mu\textrm{m}$/hr, which value increased with Rochelle Salts addition. Adhesion strength between ceramic boards and Cu layer was improved of 20% when using ultrasonic agitation at $30^{\circ}C$ ,5min.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.737-746
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• 1990

Ga0.47In0.53As PIN photodiodes(PD) having various areas have been fabricated by liquid phase epitaxial techniques. Ternary melt has been baked out at 675\ulcorner in H2 atmosphere for 20 hours before growth, which resulted in reduction of background carrier concentration of grown epi-layer. Also, lattice mismatch has been controlled within 0.01%. The room temperature performance of 10**-4cm\ulcornerarea PIN PD at a bias voltage of -5V were` quantum efficiency(with no antireflection coating)=60% for 1.3\ulcorner light source, dark current\ulcorner5nA, and capacitance\ulcornerpE. Frequency response measurement of packaged PIN PD has shown that cut-off frequency (f-3dB) was 961MHz. This PD has shown a good eye pattern when it was incorporated in a 565Mbps optical receiver.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.353-358
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• 1994

Grain yields of errect-leaved corn hybrids were reported to be increased as planting density(PD) increased compared to those of horizontal leaf type hybrids. This trial was conducted to investigate the difference between errect and horizontal-leaved hybrids in response to different PD. Grain yields of both type hybrids were decreased at the highest PD, however, that of horizontal-leaved hybrid, Ga209 ${\times}$ Ki14A, was decreased more than errect-leaved hybrids which indicated varietal difference in response to PD. Responses to PD for days to tasseling, plant height, ear height, and leaf angle were not significant, also, PD ${\times}$ hybrid interactions were not observed. Yield components were decreased as PD increased and there were no PD ${\times}$ hybrid interactions for these characters. Leaf angle was negatively correlated with grain yield and yield components except for kernel weight.

• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.679-684
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• 1992

New Pd(IV) complexes have been prepared through the reactions of $trans-[Pd(en)_2Cl_2](ClO_4)_2 $(en = ethylenediamine) with Guanine, Adenine, or Uracil anion as purine and pyrimidine base. We identified the ratio of central metal versus ligands by $C{\cdot}H{\cdot}N$ elemental analysis and proposed the coordinating site of the base by infrared spectrum, $^1H-NMR,\; and\; ^{13}C$-NMR spectrum. Guanine or Adenine ligand coordinated at N7 site and an en ligand exchanged for $ClO_4^-$ counter ions of the starting material . As these results, the complexes showed the formula $[Pd(en)L_2(ClO_4)_2](ClO_4)_2{\cdot}(en)$, (L = Guanine, Adenine). But in the Uracil complex no exchange of the en ligand and $ClO_4^-$ occured and Uracil anion preferred the N1 to N3 as coordinating site, the complex $[Pd(en)_2(Urac)_2](ClO_4)_2(Urac = Uracil anion).$

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.55-62
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• 2015

It is widely accepted that Parkinson's disease(PD) is the most common cause of hypokinetic dysarthria, and its characteristics of 'short rushes of speech' have become more evident along with the severity of motor disorders. Speech alternate motion rates (AMRs) are particularly useful for observing not only rate abnormalities but also deviant speech. However, relatively little is known about the characteristics of 'short rushes of speech' in terms of AMRs of PD except for the perceptual characteristics. The purpose of this study was to examine which acoustic features of 'short rushes of speech' in terms of AMRs are a robust indicator of Parkinsonian speech. Numbers of syllabic repetitions (/pə/, /tə/, /kə/) in AMR tasks were analyzed through acoustic methods observing a spectrogram of the Computerized Speech Lab in 9 patients with PD. Acoustically, we found three characteristics of 'short rushes of speech': 1) Vocalized consonants without closure duration(VC) 76.3%; 2) No consonant segmentation(NC) 18.6%; 3) No vowel formant frequency(NV) 5.1%. Based on these results, 'short rushes of speech' may affect the failure to reach and maintain the phonatory targets. In order to best achieve the therapeutic goals, and to make the treatment most efficacious, it is important to incorporate training methods which are based on both phonation and articulation.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.71-76
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• 1998

Crystal structure of Bis(ethylenediamine)palladium(II)-Bis(oxalato)palladate(II0 has been determined by X-ray crystallography. Crystal data : (Pd(C2H8N2)2.Pd(C2O4)2), Fw=509.04, Monocline, Space Group P21/c (no=14), a=6.959(2), b=13.506(2), c=15.339(2) Å, β=99.94(3), Z=4, V=1420 Å3, Dc=2.380 gcm-3, μ=25.46cm-1, F(000)=992. The intensity data were collected with Mo-Kα radiation (λ=0.7107 Å) on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were R=0.021, Rw=0.030, Rall=0.032 abd S=2.1 for 1472 observed reflections. The essentially planar complex anions form diade of interplanar distances of 3.41 Å and their diads are stacked along aaxis with interplanar separation of 3.44 Å.