• Korean Journal of Metals and Materials
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• v.49 no.6
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• pp.493-497
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• 2011

The basic properties and electrical characteristics of sputtering films deposited with a commercial cast target and spark plasma sintering (SPS) were compared and analyzed. The results, revealed that, the Al film prepared by heating at $60^{\circ}C/min$ (SPS process) showed a specific resistance similar to the commercial cast Al film. In addition, the results of XRD, SIMS and TEM, showed that there was not much difference in the crystal structure and impurities between the two films. Consequently, the SPS Al target was found to have properties quite similar to the commercial one and it is expected to be applied in future research to the metal wiring material for semiconductor/display devices.

• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.238-245
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• 2023

0.75(Bi_1/2Na_1/2)TiO₃-0.25SrTiO₃ (BNT-25ST) ceramics with high densities were successfully prepared at a sintering temperature of 1,000℃ by adding a mixture of 1 mol% CuO and 0.5 mol% Na₂CO₃ or 0.5 mol% CuO and 0.25 mol% Na₂CO₃. Double polarization-electric field (P-E) hysteresis curves and sprout-shaped bipolar strain-electric field (S-E) hysteresis curves with small negative strains were observed in the pristine and CuO-added BNT-25ST ceramics whereas the Na₂CO₃-added sample showed similar P-E and S-E curves to a typical ferroelectric. The pristine BNT-25ST ceramics showed an extremely large strain and a large-signal piezoelectric strain constant (d₃₃^*): 0.287 % at 80 kV/cm and 850 pm/V at 20 kV/cm. Similar values, 0.248 % at 80 kV/cm and 655 pm/V at 20 kV/cm, were obtained in the CuO-added sample. However, the pristine and CuO-added samples showed large hysteresis in unipolar S-E curves at an electric field of less than 20 kV/cm. The Na₂CO₃-added sample showed smaller values of the strain and d₃₃^* but displayed a linear change and small hysteresis in the unipolar S-E curve. The co-added sample with CuO and Na₂CO₃ displayed intermediate P-E and S-E hysteresis curves.

• Journal of Information Display
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• v.2 no.3
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• pp.39-43
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• 2001

The glass compositions of $PbO-SiO_2-B_2O_3$ system and $P_2O_5-PbO-ZnO$ system for the transparent dielectric materials for front panel and $P_2O_5$-ZnO-BaO and $SiO_2-ZnO-B_2O_3$ for the reflective dielectric materials for back panel of PDP (Plasma Display Panel) were investigated. As a result, transparent dielectric materials for front panel showed good dielectric properties, high transparency, and proper thermal expansion matching to soda lime glass substrate. And the reflective dielectric layers for back panel were prepared from two series of parent glass and oxide filler. It was found that these glassceramics are useful materials for dielectric layers in PDP device, as they have similar thermal expansion to soda-lime glass plate, high reflectance, and low sintering temperature. In particular, the addition of $BPO_4$ and $TiO_2$ as fillers to $SiO_2-ZnO-B_2O_3$ system is considered to be the most effective for acquiring good properties of lower dielectric layer for PDP device.

• Journal of Construction Engineering and Project Management
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• v.4 no.1
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• pp.8-14
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• 2014

The Construction industry in Yemen confronts many development constraints, such as the inadequate implementation of appropriate building materials and labour construction technologies. Thus, this research looks over building materials and labour construction technologies used on the local housing construction projects by verifying the percentage of construction expenditure consumed by the main construction components (Materials, Labour and Overhead and Profit), along with the implemented construction technologies. The paper conducts a survey to acquire the cost distribution of the construction main components. The outcomes of the survey were discussed; the discussion was supported by literature on similar issues from some countries. The outcomes confirmed the relatively limited percentage in labour cost and profit, and the elevated percentage of construction materials cost, which are because of the excessive and inappropriate use of materials. What's more, established that the excessively redundant unskilled labours are not effectively engaged in the construction activities, this is due to the tendency of the market in using labour-base technologies. This paper is to recommend a suitable policies and strategies has to be used to decrease cost by using efficiently appropriate construction practice and local materials, moreover take advantage of excessive labour to reduce unemployment.

• Journal of Veterinary Clinics
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• v.13 no.2
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• pp.184-194
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• 1996

A comparative study of three absorbable suture materials of chromic catgut, Dexon II (a polyglycolic acid suture with a polycaprolate coating system) and Coated Vicryl (a polyglactin 910 suture with a glycolide-lactide-calcium stearate coating system) was undertaken in terms of tensile strength, breaking elongation, appearances of the suture materials in the subcutaneous layer of rats and of tissue reaction in the intramuscular layer of rats. The initial tensile strength of chromic catgut and the tensile strength after 21 days were about 1.55 kg and 0.19 kg, respectively. Those of Dexon II were about 2.01 kg and 0. 20 kg, respectively. Those of Coated Vicryl were about 2.39 kg and 0.48 kg, respectively. Coated Vicryl showed the highest tensile strength among the three materials during the whole period. On the other hand, Dexon II showed the highest breaking elongation among the three materials during the first week. But the breaking elongation of Dexon II rapidly continuously decreased during the whole period. The appearances of the suture materials in the subcutaneous layer of rats showed that chromic catgut was the fastest among the three materials, whereas it formed comparatively much connective tissue. The intramuscular absorption rate and tissue reaction of Dexon II were similar to those of Coated Vicryl. The intramuscular absorption rate of these was fairly late when compared with chromic catgut. And the tissue reaction appearance of these showed the formation of a granuloma with foreign body giant cells, macrothages and epitheloid cells by the 28th day in the experimental period.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1425-1428
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• 2007

The amorphous IZO on flexible substrate (PC) shows similar electrical conductivity and optical transmittance with commercial ITO glass even though it was prepared at $<50\;^{\circ}C$. Moreover, it exhibits little resistance change during 5000 bending cycles, demonstrating good mechanical robustness. A green phosphorescent OLED fabricated on amorphous IZO on flexible PC shows maximum external quantum efficiency of ${\eta}_{ext}=13.7\;%$ and power efficiency of ${\eta}_p=32.7\;lm/W$, which are higher than a device fabricated on a commercial ITO on glass (${\eta}_{ext}=12.4%$ and ${\eta}_p=30.1\;lm/W$) and ITO on flexible PC (${\eta}_{ext}=8.5%$ and ${\eta}_p=14.1\;lm/W$).

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.156-157
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• 2006

Quasi-living polymerization conditions for the copolymerization of ethylene and functionalized norbornenes can be achieved by using an initiator system comprising $[N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)-propanamidato-{\kappa}^2N,O]Ni({\Box}^1-CH_2Ph)(PMe_3)\;and\;Ni(COD)_2$. It is possible with this polymerization system to obtain block-copolymer and tapered structures. The latter form microdomains similar to those of standard block co-polymers. The mechanism of the reaction will also be discussed.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.625-630
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• 2008

In the bone cement composed of dense granules of $\beta-Ca_3(PO_4){_2}(\beta-TCP)$ and $Ca(H_2PO_4){_2}H_2O$, the compressive strength, setting time and temperature rise were measured to observe the degradation of cement with respect to the stored days before setting. Decreases of compressive strength and temperature rise were observed, while setting time increased with respect to the stored days. The similar trends were repeated with the increase of temperature of storage. Such a change virtually meant the fading of the character of cement and it took place only when the two starting materials were mixed during storage. The degradation could be mitigated taking advantage of granular $\beta$-TCP instead of powdery one. The formation of $CaHPO_4$, which resulted from reaction with ambient humidity, was attributed to the degradation observed during storage. Dependence of the degradation behavior on mixing and temperature during storage was discussed in terms of the driving force for reaction of cement.

• ETRI Journal
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• v.31 no.6
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• pp.688-694
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• 2009

In this paper, we present the results of a preliminary study on the piezoelectric energy harvesting performance of a Zr-doped $PbMg_{1/3}Nb_{2/3}O_3-PbTiO_3$ (PMN-PZT) single crystal beam. A novel piezoelectric beam cantilever structure is used to demonstrate the feasibility of generating AC voltage during a state of vibration. The energy-harvesting capability of a PMN-PZT beam is calculated and tested. The frequency response of the cantilever device shows that the first mode resonance frequency of the excitation model exists in the neighborhood of several hundreds of hertz, which is similar to the calculated value. These tests show that several significantly open AC voltages and sub-mW power are achieved. To test the possibility of a small scale power source for a ubiquitous sensor network service, energy conversion and the testing of storage experiment are also carried out.

• Journal of the Korean Ceramic Society
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• v.37 no.4
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• pp.320-326
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• 2000

Development of texture in SiC materials by hot-pressing and subsequent annealing was studied. Crystallographic texture type was characterized by measuring X-ray pole figures on the perpendicular plane to the hot-pressing direction. Observed all pole figures were nearly axially symmetric (fiber texture). In case of ${\beta}$-SiC materials, the pole density of basal plane (0004) increased as annealing time increased, in contrast, other planes (hkil) of ${\beta}$-SiC materials and all planes of ${\alpha}$-SiC materials nearly remained unchanged. In the case of ${\beta}$-SiC materials, therefore, a weak texture of (0001) plane at the normal direction took place in the 8h annealed samples, resulting from grian growth. The fracture toughness values of ${\alpha}$-SiC materials measured in both planes parallel and perpendicular to the hot-pressing direction were very similar. However, the fracture toughness of ${\beta}$-SiC materials measured parallel to the hot-pressing direction were higher than that measured perpendicular to the hot-pressing derection, relatively, because of the texture and the microstructure anisotropy.