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We used a pulsed green laser to activate indium gallium zinc oxide thin-film transistors (IGZO TFTs). The IGZO films with large bandgaps (>3 eV) were easily activated by heat delivered by a pulsed green laser to the gate, source, and drain metal electrodes. The IGZO TFTs were quickly and selectively activated in the absence of conventional annealing. Compared to the IGZO TFTs that were annealed at 300°C, the IGZO TFTs that were activated via pulsed green laser irradiation exhibited superior electrical characteristics: a field effect mobility of 11.98 ± 0.64 cm2 V−1 s−1, a subthreshold swing of 0.33 ± 0.02 V dec−1, and an on/off ratio of 8.28 × 109 ± 7.42 × 109, which were attributable to increases in the number of metal–oxide (M-O) bonds and oxygen vacancies, and reduced levels of OH-related species. The pulsed green laser broke weak chemical M-O bonds in the IGZO films through dihydroxylation of the OH-related species, and then strengthened the residual M-O bonds via heat transfer from the metal electrodes. This new activation process could replace conventional annealing and is expected to expand the applications of flexible and transparent devices.

Background: Recently, three-dimensional (3D) printing has been hailed as a disruptive technology in dentistry. Among 3D printers, a digital light processing (DLP) 3D printer has certain advantages, such as high precision and relatively low cost. Therefore, the latest trend in resin crown manufacturing is the use of DLP 3D printers. However, studies on the internal fitness of such resin crowns are insufficient. The recently introduced 3D evaluation method makes it possible to visually evaluate the error of the desired area. The purpose of this study is to evaluate the internal fitness of resin crowns fabricated a by DLP 3D printer using the 3D evaluation method. Methods: The working model was chosen as the maxillary molar implant model. A total of 20 resin crowns were manufactured by dividing these into two groups. One group was manufactured by subtractive manufacturing system (PMMA), while the other group was manufactured by additive manufacturing system, which uses a DLP 3D printer. Resin crowns data were measured using a 3D evaluation program. Internal fitness was calculated by root mean square (RMS). The RMS was calculated using the Geomagic Verify software, and the mean and standard deviation (SD) were measured. For statistical analysis, IBM SPSS Statistics for Windows ver. 22.0 (IBM Corp., USA) was used. Then, independent t-test was performed between the two groups. Results: The mean±SD of the RMS were 41.51±1.51 and 43.09±2.32 for PMMA and DLP, respectively. There was no statistically significant difference between PMMA and DLP. Conclusion: Evaluation of internal fitness of the resin crown made using a DLP 3D printer and subtractive manufacturing system showed no statistically significant differences, and clinically acceptable results were obtained.

We proposed a novel material named sodium hypochlorite (NaClO) solution as a source of activation for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). We reduced the activation temperature from 300 to 150 °C using NaClO solution (concentration: 50%) and obtained satisfactory electrical characteristics of a-IGZO TFTs. The field-effect mobility, threshold voltage, on/off ratio, subthreshold swing, and threshold voltage (Vth) shift under negative bias illumination stress (VG = -20 V and VD = 10.1 V for 10,000 s) of NaClO (50%)-activated a-IGZO TFTs were 10.41 cm2/V·s, 1.51 V, 2.78 × 108, 0.37 V/dec, and -5.43 V, respectively. Also, the Vth shifts of the NaClO (50%)-activated a-IGZO TFTs (150 °C) under the positive bias stress test decreased from 5.01 to 1.87 V (VG = 20 V and VD = 10.1 V for 10,000 s) compared with that of only-annealed (300 °C) a-IGZO TFTs. Also, the mechanism of NaClO activation for a-IGZO TFTs is clarified through photo-assisted oxygen radical (POR) and heat-driven oxygen radical (HOR) effects. The POR and HOR effects generated the reactive oxygen species (ROS) from NaClO solution (50%), which activated a-IGZO TFTs at a low temperature (150 °C). When the NaClO solution (50%) was exposed to external energy, it generated ROS such as hydroxyl radicals (OH•), hydroperoxyl radicals (HO2•), and oxygen radicals (O•), which promoted the formation of strong metal-oxide bonds in a-IGZO TFTs. Furthermore, NaClO solution (50%) was applied to a-IGZO TFTs on a flexible polyimide substrate and electrohydrodynamic printing process for selective deposition.

We present a solution-processed oxide absorption layer (SAL) for detecting visible light of long wavelengths (635 and 532 nm) for indium-gallium-zinc oxide (IGZO) phototransistors. The SALs were deposited onto sputtered IGZO using precursor solutions composed of IGZO, which have the same atomic configuration as that of the channel layer, resulting in superior interface characteristics. We artificially generated subgap states in the SAL using a low annealing temperature (200 °C), minimizing the degradation of the electrical characteristics of thin-film transistor. These subgap states improved the photoelectron generation in SALs under visible light of long wavelength despite the wide band gap of IGZO (∼3.7 eV). As a result, IGZO phototransistors with SALs have both high optical transparency and superior optoelectronic characteristics such as a high photoresponsivity of 206 A/W and photosensitivity of ∼106 under the influence of a green (532 nm) laser. Furthermore, endurance tests proved that the IGZO phototransistor with SALs can operate stably under red laser illumination switched on and off at 0.05 Hz for 7200 s.

Visible light can be detected using an indium–gallium–zinc oxide (IGZO)-based phototransistor, with a selenium capping layer (SCL) that functions as a visible light absorption layer. Selenium (Se) exhibits photoconductive properties as its conductivity increases with illumination. We report an IGZO phototransistor with an SCL (SCL/IGZO phototransistor) that demonstrated optimal photoresponse characteristics when the SCL was 150 nm thick. The SCL/IGZO phototransistor exhibited a photoresponsivity of 1.39 × 103 A/W, photosensitivity of 4.39 × 109, detectivity of 3.44 × 1013 Jones, and external quantum efficiency of 3.52 × 103% when illuminated by green light (532 nm). Ultraviolet–visible spectroscopy and ultraviolet photoelectron spectroscopy analysis showed that Se has a narrow energy band gap, in which visible light is absorbed and forms a p–n junction with IGZO so that photogenerated electron–hole pairs are easily separated, which makes recombination more challenging. We show that electrons generated in ...

Sputter-processed oxide films are typically annealed at high temperature (activation process) to achieve stable electrical characteristics through the formation of strong metal-oxide chemical bonds. For instance, indium-gallium-zinc oxide (IGZO) films typically need a thermal treatment at 300 °C for ≥1 h as an activation process. We propose an open-air plasma treatment (OPT) to rapidly and effectively activate sputter-processed IGZO films. The OPT effectively induces metal-oxide chemical bonds in IGZO films at temperatures as low as 240 °C, with a dwell time on the order of a second. Furthermore, by controlling the plasma-processing conditions (scan speed, distance a between plasma nozzle and samples, and gas flow rate), the electrical characteristics and the microstructure of the IGZO films can be easily tuned. Finally, OPT can be utilized to implement a selective activation process. Plasma-treated IGZO thin-film transistors (TFTs) exhibit comparable electrical characteristics to those of conventionally thermal treated IGZO TFTs. Through in-depth optical, chemical, and physical characterizations, we confirm that OPT simultaneously dissociates weak chemical bonds by UV radiation and ion bombardment and re-establishes the metal-oxide network by radical reaction and OPT-induced heat.

In recent decades, oxide thin-film transistors (TFTs) have attracted a great deal of attention as a promising technology in terms of next-generation electronics due to their outstanding electrical performance. However, achieving robust electrical characteristics under various environments is a crucial challenge for successful realization of oxide-based electronic applications. To resolve the limitation, we propose a highly flexible and reliable heterogeneous organic passivation layer composed of stacked parylene-C and diketopyrrolopyrrole-polymer films for improving stability of oxide TFTs under various environments and mechanical stress. The presented multifunctional heterogeneous organic (MHO) passivation leads to high-performance oxide TFTs by: (1) improving their electrical characteristics, (2) protecting them from external reactive molecules, and (3) blocking light exposure to the oxide layer. As a result, oxide TFTs with MHO passivation exhibit outstanding stability in ambient air as well as under light illumination: the threshold voltage shift of the device is almost 0 V under severe negative bias illumination stress condition (white light of 5700 lx, gate voltage of -20 V, and drain voltage of 10.1 V for 20 000 s). Furthermore, since the MHO passivation layer exhibits high mechanical stability at a bending radius of ≤5 mm and can be deposited at room temperature, this technique is expected to be useful in the fabrication of flexible/wearable devices.

To broaden the availability and application of metal–oxide (M–O)-based optoelectronic devices, we suggest heterogeneous phototransistors composed of In–Ga–Zn–O (IGZO) and methylammonium lead iodide (CH3NH3PbI3) layers, which act as the amplifier layer (channel layer) and absorption layer, respectively. These heterogeneous phototransistors showed low persistence photocurrent compared with IGZO-only phototransistors and exhibited high photoresponsivity of 61 A/W, photosensitivity of 3.48 × 106, detectivity of 9.42 × 1010 Jones, external quantum efficiency of 154% in an optimized structure, and high photoresponsivity under water exposure via the deposition of silicon dioxide as a passivation layer. On the basis of these electrical results and various analyses, we determined that CH3NH3PbI3 could be activated as a light absorption layer, current barrier, and plasma damage blocking layer, which would serve to widen the range of applications of M–O-based optoelectronic devices with high photoresponsivity and re...

In this research article, instant glue (IG) is proposed as a novel material for the passivation layer of indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs). This material can be deposited using a facile solution process and annealed at a low temperature of 150 °C for 1 min. The IGZO TFTs with an IG passivation layer (PVL) exhibit improved electrical characteristics as well as stability under positive bias stress compared to those without a PVL: field effect mobility from 10.23 to 12.66 cm2 V−1 s−1, subthreshold swing from 0.36 to 0.35 V per decade, on/off ratio from 1.6 × 108 to 5.21 × 108, and threshold voltage shift from 4.00 to 2.32 V. These improvements are attributed to the modification of the chemical stoichiometry of the IGZO films and the blocking of the adsorption of moisture and oxygen. Furthermore, by depositing IG materials selectively on IGZO films via the drop casting method, it was confirmed that an IG PVL can be fabricated at the desired location as well as in a large area due to the high adhesive strength and viscosity of IG.

We proposed a simple method, a thermally purified solution (TPS) process, to lower the fabrication temperature of solution-processed hafnium oxide (HfOx) gate insulator films. The TPS process is proceeded by transferring thermal energy to the HfOx precursor solution ‘BEFORE’ film formation. The TPS process could induce chemical reactions including pre-hydrolysis by thermal energy in the HfOx precursor solution. These chemical reactions reduce the required thermal energy for forming a solution-processed HfOx film and improve the film quality. As a result, the HfOx film fabricated via the TPS process has satisfactory dielectric characteristics: a breakdown electric field of ∼6 MV cm−1, a leakage current density of ∼10−9 A cm−2, and a dielectric constant of 10.23 at low temperatures, i.e., below 200 °C. Solution-processed indium oxide (In2O3) thin film transistors with a HfOx gate insulator fabricated via the TPS process exhibit a field effect mobility of 3.67 cm2 V−1 s−1, an on/off current ratio of 9.8 × 106, and a subthreshold swing of 0.18 V dec−1.

A novel organic material named ‘collodion’ was suggested as a gate insulator for amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs). To find the optimized condition of the collodion gate insulator (CGI), the following three parameters of collodion solution were controlled: (1) the concentration of collodion solution; (2) the number of stacked layers; and (3) the spin-coating speed. The single-layered diluted CGI (collodion:ethanol=1:1) that was fabricated with a 3 krpm spin-coating speed exhibited an acceptable dielectric strength (J

Proposed herein is a new technique of activation for the backplane of low-temperature amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) by applying a bias voltage to gate, sou...

In this research, nitrocellulose is proposed as a new material for the passivation layers of amorphous indium gallium zinc oxide thin film transistors (a-IGZO TFTs). The a-IGZO TFTs with nitrocellulose passivation layers (NC-PVLs) demonstrate improved electrical characteristics and stability. The a-IGZO TFTs with NC-PVLs exhibit improvements in field-effect mobility (μFE) from 11.72 ± 1.14 to 20.68 ± 1.94 cm2/(V s), threshold voltage (Vth) from 1.85 ± 1.19 to 0.56 ± 0.35 V, and on/off current ratio (Ion/off) from (5.31 ± 2.19) × 107 to (4.79 ± 1.54) × 108 compared to a-IGZO TFTs without PVLs, respectively. The Vth shifts of a-IGZO TFTs without PVLs, with poly(methyl methacrylate) (PMMA) PVLs, and with NC-PVLs under positive bias stress (PBS) test for 10,000 s represented 5.08, 3.94, and 2.35 V, respectively. These improvements were induced by nitrogen diffusion from NC-PVLs to a-IGZO TFTs. The lone-pair electrons of diffused nitrogen attract weakly bonded oxygen serving as defect sites in a-IGZO TFTs. Con...

Activation using the simultaneous UV-thermal (U-T) treatment of sputter-processed InGaZnO (IGZO) thin-film transistors (TFTs) is suggested. This treatment was performed to lower the activation temperature from 300°C (thermal activation alone) to 150°C as well as to improve the electrical characteristics and stability. Despite the low temperature, the U-T-treated devices showed superior electrical characteristics and stability compared to the devices that were only thermally activated (300°C): the mobility improved from 5.19 ± 1.8 to 16.20 ± 1.5 cm2/Vs, the on-off ratio increased from (5.58 ± 3.21) × 108 to (2.50 ± 2.23) × 109, and the threshold voltage shift (under positive bias stress for 1000 s) decreased from 7.1 to 2.2 V. These improvements are attributed to the following two contributions: (1) generation of reactive oxygen radical at a low temperature and (2) decomposition-rearrangement of the metal oxide (MO) bonds in the IGZO active layer. Contributions (1) and (2) effectively increased the...

We suggest thermal treatment with static magnetic fields (SMFs) or rotating magnetic fields (RMFs) as a new technique for the activation of indium–gallium–zinc oxide thin-film transistors (IGZO TFTs). Magnetic interactions between metal atoms in IGZO films and oxygen atoms in air by SMFs or RMFs can be expected to enhance metal–oxide (M–O) bonds, even at low temperature (150 °C), through attraction of metal and oxygen atoms having their magnetic moments aligned in the same direction. Compared to IGZO TFTs with only thermal treatment at 300 °C, IGZO TFTs under an RMF (1150 rpm) at 150 °C show superior or comparable characteristics: field-effect mobility of 12.68 cm2 V–1 s–1, subthreshold swing of 0.37 V dec–1, and on/off ratio of 1.86 × 108. Although IGZO TFTs under an SMF (0 rpm) can be activated at 150 °C, the electrical performance is further improved in IGZO TFTs under an RMF (1150 rpm). These improvements of IGZO TFTs under an RMF (1150 rpm) are induced by increases in the number of M–O bonds due to e...

To broaden the availability and application of metal-oxide (M-O)-based optoelectronic devices, we suggest heterogeneous phototransistors composed of In-Ga-Zn-O (IGZO) and methylammonium lead iodide (CH

A homojunction-structured amorphous indium gallium zinc oxide (a-IGZO) phototransistor that can detect visible light is reported. The key element of this technology is an absorption layer composed of hydrogen-doped a-IGZO. This absorption layer is fabricated by simple hydrogen plasma doping, and subgap states are induced by increasing the amount of hydrogen impurities. These subgap states, which lead to a higher number of photoexcited carriers and aggravate the instability under negative bias illumination stress, enabled the detection of a wide range of visible light (400–700 nm). The optimal condition of the hydrogen-doped absorption layer (HAL) is fabricated at a hydrogen partial pressure ratio of 2%. As a result, the optimized a-IGZO phototransistor with the HAL exhibits a high photoresponsivity of 1932.6 A/W, a photosensitivity of 3.85 × 106, and a detectivity of 6.93 × 1011 Jones under 635 nm light illumination.

We fabricated wire-type indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) using a self-formed cracked template based on a lift-off process. The electrical characteristics of wire-type IGZO TFTs could be controlled by changing the width and density of IGZO wires through varying the coating conditions of template solution or multi-stacking additional layers. The fabricated wire-type devices were applied to sensors after functionalizing the surface. The wire-type pH sensor showed a sensitivity of 45.4 mV/pH, and this value was an improved sensitivity compared with that of the film-type device (27.6 mV/pH). Similarly, when the wire-type device was used as a glucose sensor, it showed more variation in electrical characteristics than the film-type device. The improved sensing properties resulted from the large surface area of the wire-type device compared with that of the film-type device. In addition, we fabricated wire-type IGZO TFTs on flexible substrates and confirmed that such structures were very resistant to mechanical stresses at a bending radius of 10 mm.

Different applied potentials have been employed in a two-step anodization process, utilizing a 1 M H3PO4 electrolyte and a solution containing this electrolyte and 0.8 wt.% NaF, to control the shape and morphology of oxide nanotubes on coatings for ternary Ti–30Ta–xZr alloys. The ternary alloys were manufactured using an arc furnace, and corrosion testing was carried out using a potentiostat. The microstructures of the Ti–30Ta–xZr alloys had a needle-like structure, and the lath thickness of the α′ phase increased as the Zr content increased. The microstructures of Ti–30Nb–xZr alloys had equiaxed grains. The Ti–30Nb–xZr alloys showed smaller micropores and nanotubes compared to the Ti–30Ta–xZr alloys. The Ti–Nb(Ta)–Zr alloys tended to have improved corrosion resistance with increasing Zr content.

동물의 에너지수지에 관한 연구는 에너지 흐름을 이해하고 동 물생태계의 기능을 파악하는데 있어 유용한 수단이 된다. 생태 계는 복잡한 먹이사슬 또는 먹이그물과 같은 영양적 구조로 집 단 간의 에너지흐름의 양에 밀접하게 관련되어 있으며, 이러한 복잡한 먹이망 속에서 그 물질의 전환에 따른 에너지 흐름을 파악하기 위해서 에너지수지를 분석하는 것이 매우 중요하다 (Klekowski and Duncan, 1975). 어느 한 생물의 개체에 유입되 는 모든 에너지는 열로써 상실하거나, 다른 영양 단계로 전이된 다. 생물학적 물질계는 물질전환에 따른 에너지 흐름에 의해서 체계화되어 있다. 그리고 먹이사슬로 또는 먹이그물과 같은 영 양적 구조는 집단의 에너지 흐름의 양에 밀접하게 관련된다. 그 러므로 에너지 흐름의 파악은 자연집단의 에너지수지를 분석하 는 것이 필요하지만, 우선 개체의 생활사에 따른 에너지수지를 정확하게 분석하는 것이 매우 중요하다(Park, 1989). 갑각류의 에너지수지에 관해서는 자연과 실험실 내 집단을 대 상으로 많은 연구가 진행되어 있으며(Clutter and Theilacker, 1971; Levine and Sulkin, 1979; Emmerson, 1984; Harms, 1987; Kim and Chin, 1991), 성장, 산소소비, 질소배설 및 섭취 에 대한 에너지 함량을 파악하여 에너지수지 방식을 통해서 그 영양적 체계를 구성해 볼 수 있다(Park, 1989). 동물의 에너지 수지에 관한 연구는 다른 영양 단계 간의 에너지 전이유형을 이 해하는 총체적 지표가 되며, 그 동물의 생산성과 생태적 효율을 예측하는 자료로서 유용하다(Vernberg and Vernverg, 1981). 가시배새우, Lebbeus groenlandicus는 십각목(Order Decapoda) 꼬마새우과(Family Hippolytidae)에 속하는 종으로 꼬마 새우과 중에서도 거대 종이며, 특히 한국산 꼬마새우과 중에서 는 가장 크다. 몸이 짧고 굵으며, 두흉갑이 짧고 거친 털로 덮여 있다. 이 종은 울릉도 근해에서 통발로 주로 어획하는데, 수심 200-400 m에 주로 서식한다. 한해성 종으로서 아한대 해역에 분포하고 있다. 우리나라 동해, 그린란드, 미국 동북부, 캐나다

We investigated the effects of high-pressure annealing as a source of activation energy to form the amorphous indium gallium zinc oxide (a-IGZO) channel layer at 100°C. Thermal activation under oxygen pressure was used to facilitate the formation of channel layer as well as to improve positive bias stress stability.

Carbon nanotubes, in different forms and architectures, have demonstrated good promise as electrode material for Li-ion batteries, owing to large surface area, shorter Li-conduction distance and high electrical conductivity. However, practical application of such Li-ion batteries demands higher volumetric capacity, which is otherwise low for most nanomaterials, used as electrodes. In order to address this urgent issue, we have developed a novel 3-dimensional (3D) anode, based on multiwall carbon nanotubes (MWCNTs), for Li-ion batteries. The unique 3D design of the electrode allowed much higher solid loading of active anode material, MWCNTs in this case and resulted in more amount of Li + ion intake in comparison to those of conventional 2D Cu current collector. Though one such 3D anode was demonstrated to offer 50% higher capacity, compared to its 2D counterpart, its ability to deliver much higher capacity, by geometrical modification, is presented. Furthermore, deposition of amorphous Si (a-Si) layer on the 3D electrode (a-Si/MWCNTs hybrid structure) offered enhancement in electrochemical response. Correlation between electrochemical performances and structural properties of the 3D anodes highlights the possible charge transfer mechanism.

A new technique is proposed for the activation of low temperature amorphous InGaZnO thin film transistor (a-IGZO TFT) backplanes through application of a bias voltage and annealing at 130 °C simultaneously. In this ‘electrical activation’, the effects of annealing under bias are selectively focused in the channel region. Therefore, electrical activation can be an effective method for lower backplane processing temperatures from 280 °C to 130 °C. Devices fabricated with this method exhibit equivalent electrical properties to those of conventionally-fabricated samples. These results are analyzed electrically and thermodynamically using infrared microthermography. Various bias voltages are applied to the gate, source, and drain electrodes while samples are annealed at 130 °C for 1 hour. Without conventional high temperature annealing or electrical activation, current-voltage curves do not show transfer characteristics. However, electrically activated a-IGZO TFTs show superior electrical characteristics, comparable to the reference TFTs annealed at 280 °C for 1 hour. This effect is a result of the lower activation energy, and efficient transfer of electrical and thermal energy to a-IGZO TFTs. With this approach, superior low-temperature a-IGZO TFTs are fabricated successfully.

We investigated the use of high-pressure gases as an activation energy source for amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs). High-pressure annealing (HPA) in nitrogen (N2) and oxygen (O2) gases was applied to activate a-IGZO TFTs at 100 °C at pressures in the range from 0.5 to 4 MPa. Activation of the a-IGZO TFTs during HPA is attributed to the effect of the high-pressure environment, so that the activation energy is supplied from the kinetic energy of the gas molecules. We reduced the activation temperature from 300 °C to 100 °C via the use of HPA. The electrical characteristics of a-IGZO TFTs annealed in O2 at 2 MPa were superior to those annealed in N2 at 4 MPa, despite the lower pressure. For O2 HPA under 2 MPa at 100 °C, the field effect mobility and the threshold voltage shift under positive bias stress were improved by 9.00 to 10.58 cm2/V.s and 3.89 to 2.64 V, respectively. This is attributed to not only the effects of the pressurizing effect but also the metal-oxide construction effect which assists to facilitate the formation of channel layer and reduces oxygen vacancies, served as electron trap sites.

Purpose: The purpose of this study is to lay the groundwork for the development of appropriate training courses for a rapidly changing digital technology in the field of Dental technology. Methods: The subjects of this study were dental technicians, dental technology students, a professor of dental technology in Daegu and Gyeongbuk area and a self-administered structured questionnaire survey was conducted for 350 randomly selected people. Collected data were analyzed using SPSS Win 17.0 statistics program and analysis techniques include the frequency, percentage and cross-analysis. Results: The results of the survey are as follows. The usefulness of Major subjects was Full Denture laboratory (4.72 points), Dental Morphology (4.71 points), Crown and Bridge laboratory (4.69 points) in the instructor`s group. The usefulness of Major subjects was Dental Morphology (4.56 points), Full Denture (4.36 points), Crown and Bridge laboratory (4.69 points) in the student`s group. The usefulness of Major subjects was Dental Morphology (4.58 points), Dental Morphology laboratory (4.34 points), Partial Denture laboratory (4.30 points) in the dental technician`s group. Subject with the highest usefulness of required course to open was CAD/CAM lecture and laboratory, the highest proportion of 91.2% and Implant laboratory was very useful (91.2%) in the instructor`s group. Subject with the highest usefulness of required course to open was CAD/CAM lacture and laboratory, the highest proportion of 90.0% and Implant laboratory was very useful (91.2%) in the student`s group. Subject with the highest usefulness of required course to open was CAD/CAM lacture and laboratory, the highest proportion of 91.2% and Implant laboratory was very useful (90.2%) in the dental technician`s group. Conclusion: Semester of the subjects was required establishment of CAD/CAM lecture and laboratory in the third year first semester (85.1%) and Implant laboratory in the third year second semester the third year was the highest proportion of 94.1% in the instructor`s group. 87.0% of students need to open CAD/CAM lacture and laboratory in the third year first semester, Implant laboratory in the third year second semester the third year was the highest proportion of 85.0% in the student`s group. Semester of the subjects was required establishment of CAD/CAM lecture and laboratory in the third year first semester (81.0%) and Implant laboratory in the third year second semester the third year was the highest proportion of 80.0% in the dental technician`s group.

Electrochemical characteristics of a titanium nitride (TiN)-coated/nanotube-formed Ti–Ta–Zr alloy for biomaterials have been researched by using the magnetic sputter and electrochemical methods. Ti–30Ta–xZr (x = 3, 7 and 15 wt%) alloys were prepared by arc melting and heat treated for 24 h at 1000 °C in an argon atmosphere and then water quenching. The formation of oxide nanotubes was achieved by anodizing a Ti–30Ta–xZr alloy in H3PO4 electrolytes containing small amounts of fluoride ions at room temperature. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. The microstructure and morphology of nanotube arrays were characterized by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The TiN coatings were obtained by the radio-frequency (RF) magnetron sputtering technique. The depositions were performed from pure Ti targets on Ti–30Ta–xZr alloys substrates. The corrosion properties of the specimens were examined using potentiodynamic test in a 0.9% NaCl solution by using potentiostat. The microstructures of Ti–30Ta–xZr alloys were changed from an equiaxed to a needle-like structure with increasing Zr content. The interspace between the nanotubes was approximately 20, 80 and 200 nm for Zr contents of 3, 7 and 15 wt%, respectively. The corrosion resistance of the TiN-coated on the anodized Ti–30Ta–xZr alloys was higher than that of the untreated Ti alloys, indicating a better protective effect.

The purpose of this study was to investigate the surface characteristics of hydroxyapatite (HA)/titanium (Ti) composite layer on the Ti-35Ta-xZr alloy surface by radio frequency (RF) and direct current (DC) sputtering for dental application. The magnetron sputtered deposition for the HA was performed in the RF mode and for the Ti in the DC mode. Microstructures of the alloys were examined by optical microscopy (OM) and x-ray diffractometer (XRD). Surface characteristics of coated film was investigated by field-emission scanning electron microscope (FE-SEM) equipped with an energy dispersive x-ray spectrometer (EDS), and XRD. Microstructures of the Ti-35Ta-xZr alloys were changed from α″ phase to β phase, and changed from a needle-like structure to an equiaxed structure with increasing Zr content. From the results of polarization behavior in the Ti-35Ta-15Zr alloy, HA/Ti composite layer showed the good corrosion resistance compared to Ti single layer. The results of alternating current (AC) impedance test indicated that the presence of ha coating acted as a stable barrier in increasing the corrosion resistance.

The purpose of this study was to investigate the changes of the nanostructured surface of Ti–35Ta–xZr alloys for dental application resulting from changes in anodization factors. TiO 2 nanotubes were formed on Ti–35Ta–xZr alloys by anodization in H 3 PO 4 -containing NaF solutions. Anodization was carried out using a scanning potentiostat. Microstructures of the alloys were examined by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD). Microstructures of the Ti–35Ta–xZr alloys were changed from α" phase to β phase, and morphologies changed from a needle-like to an equiaxed structure, with increasing Zr content. As the Zr content increased from 3 to 7 to 15 wt.%, the average thickness of the TiO 2 nanotubes increased from 4.5 μm to 6.1 μm to 9.0 μm. When the anodizing potential was increased from 3 V to 10 V, the thickness of the nanotube layers increased from about 0.5 μm to 9.5 μm. As the anodization time increased from 30 min to 180 min at 10 V, the nanotube thickness increased from 4 μm to 9.5 μm. The amorphous oxide phase in the nanotubes transformed to anatase and rutile phases of TiO 2 by heat treatment above 300 °C.

In this study, surface characteristics and cell proliferation of mechanical sandblasted Ti-30Ta-xNb surface have been investigated. Samples with three different surface preparations were used: 0.3um polished, 50um and 100um HA sandblasted. Cell culture on the specimen surface was performed with mouse osteoblast-like cells MC3T3-E1 for 2 days. Average surface roughness and surface morphology of specimens were observed using surface roughness tester, and field-emission scanning electron microscopy. The corrosion resistance was measured using electrochemical impedance spectroscopy and potentiodynamic test at 0.9% NaCl solution at 36.5oC. The average surface roughness of Ti-30Ta-xNb (x = 5, 10, 15wt%) alloys increased with increasing blasting particle size and Nb content. Cell adhered well on the rough surface of Ti-30Ta-xNb (x = 5, 10, 15wt%) alloys. Cell growth increased as Nb content increased. From the electrochemical test, Ti-30Ta-xNb (x = 5, 10, 15wt%) alloys blasted by 100um HA particles showed lower dissolution rate than that by 50um HA particles, especially, Ti-30Ta-15Nb alloy showed lower dissolution rate.

In this study, surface characteristics of hydroxyapatite(HA) coated Ti-30Ta-xZr and Ti-30Nb-xZr alloys after nanotube formation have been investigated by EB-PVD, FE-SEM, XRD and potentiostat. The microstructures of the Ti-30Ta-xZr alloy had a needle-like morphology, and the thickness of this needle-like structure increased as the Zr content increased. The microstructures of the Ti-30Nb-xZr alloy had an equiaxed grain structure. The nanotubes were mainly nucleated and grown at β phase in case of Ti-30Ta-3Zr, but nanotubes were nucleated at α phase in case of Ti-30Ta-15Zr alloy. The corrosion resistance of alloy increased as Zr content increased, and nanotubular surface with highly ordered small and large tubes was high corrosion resistant. The corrosion resistance of HA coated alloys after nanotube formation was higher than that of the non-HA coated nanotubular alloy.