Lead-free perovskite ceramics, which have excellent energy storage capabilities, are attracting attention owing to their high power density and rapid charge-discharge speed. Given that the energy-storage properties of perovskite ceramic capacitors are significantly improved by doping with various elements, modifying their chemical compositions is a fundamental strategy. This study investigated the effect of Zn doping on the microstructure and energy storage performance of potassium sodium niobate (KNN)-based ceramics. Two types of powders and their corresponding ceramics with compositions of (1-x)(K,Na)NbO3-xBi(Ni2/3Ta1/3)O3 (KNN-BNT) and (1-x)(K,Na)NbO3-xBi(Ni1/3Zn1/3Ta1/3) O3 (KNN-BNZT) were prepared via solid-state reactions. The results indicate that Zn doping retards grain growth, resulting in smaller grain sizes in Zn-doped KNN-BNZT than in KNN-BNT ceramics. Moreover, the Zn-doped KNNBNZT ceramics exhibited superior energy storage density and efficiency across all x values. Notably, 0.9KNN-0.1BNZT ceramics demonstrate an energy storage density and efficiency of 0.24 J/cm3 and 96%, respectively. These ceramics also exhibited excellent temperature and frequency stability. This study provides valuable insights into the design of KNNbased ceramic capacitors with enhanced energy storage capabilities through doping strategies.

The effects of Ni2+ substitution for Mg2+-sites on the microwave dielectric properties of (Mg1-xNix)(Ti0.95(Mg1/3 Ta2/3)0.05)O3 (0.01 ≤ x ≤ 0.05) (MNTMT) ceramics were investigated. MNTMT ceramics were prepared by conventional solid-state reaction. When the MgO / TiO2 ratio was changed from 1.00 to 1.02, MgTi2O5 was detected as a secondary phase along with the MgTiO3 main phase in the MNTMT specimens sintered at 1,400 °C for 4h. For the MNTMT specimens with MgO / TiO2 = 1.07 sintered at 1,400 °C for 4h, a single phase of MgTiO3 with an ilmenite structure was obtained from the entire range of compositions. The relative density of all the specimens sintered at 1,400 °C for 4h was higher than 95 %. The quality factor (Qf) of the sintered specimens depended strongly on the degree of covalency of the specimens, and the sintered specimens with x = 0.01 showed the maximum Qf value of 489,400 GHz. The dielectric constant (K) decreased with increasing Ni2+ content because Ni2+ had a lower dielectric polarizability (1.23Å3) than Mg2+ (1.32Å3). As Ni2+ content increased, the temperature coefficient of resonant frequency (TCF) improved, from -55.56 to -21.85 ppm/°C, due to the increase in tolerance factor (t) and the lower dielectric constant (K)

본 논문은 디지털 성범죄 사건이 증가하고 있는 가운데, 이들에 대한 형사사법기관 의 처분이 가해자의 행위를 교정하거나 직접적으로 제재하지 못하는 현실을 지적하고 이에 대한 대안을 고민하기 위하여 시작되었다. 이를 위해 미국에서 시행되고 있는, 성범죄자 대상 ‘음란물 금지’와 ‘인터넷 및 컴퓨터 기기활용 제한’의 내용을 비교법적 으로 검토하면서 피해자의 삶이 아닌 가해자의 삶에 타격과 변화를 줄 수 있는 법률 내용을 제안하는 것을 주요 목적으로 하였다. 미국의 ｢성범죄자 신상등록 및 고지법｣ 에는 성범죄를 행함에 있어 인터넷 또는 컴퓨터 기기를 활용한 성범죄자에 대하여 일 정 기간의 사용제한을 법원이 선고하고 이의 이행 여부를 보호관찰관이 지도･감독하 는 내용이 규정되어 있다. 관련 제도가 정착되는 과정에서 반복적인 항소도 제기되었 지만, 미국의 판례는 인터넷 활동과 컴퓨터 사용의 제한 내용이 구체적인 경우에는 큰문제가 없다는 태도를 견지하고 있다. 이 법률 규정이 적용되는 경우, 보호관찰관은 대상 성범죄자에게 모든 디지털 기기의 등록과 해당 기기에 대한 포렌식 동의서를 요 구한다. 또한 보호관찰관은 대상 성범죄자의 디지털 기기에 대한 주기적 검사를 시행 하고 대상자의 휴대폰 활동 내용을 모니터링하고 필터링하는 소프트웨어를 설치하여 집행한다. 이러한 내용은 실제 디지털 성범죄자에 대한 행동 제약이 전무한 우리나라 의 보호관찰 현실과 상당히 대비되는 모습이다. 과거 접촉성 성범죄자를 향해 시행되 었던 형사정책들이 사회적 논의 속에서 설득되고 사회제도로 자리를 잡아갔던 것처럼, 디지털 성범죄 가해자에 대한 규제와 교정, 피해 방지 대책을 더욱 직접적인 가해자 행위 규제 관점에서 고민할 필요가 있다. 이러한 측면에서 미국의 인터넷 및 컴퓨터 활동 제한 관련 법률 규정은, 우리나라에서의 효과적 디지털 성범죄자 관리대책 수립 을 위한 의미 있는 비교법적 자료가 될 것으로 판단한다.

Recently, high-entropy carbides have attracted considerable attention owing to their excellent physical and chemical properties such as high hardness, fracture toughness, and conductivity. However, as an emerging class of novel materials, the synthesis methods, performance, and applications of high-entropy carbides have ample scope for further development. In this study, equiatomic (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide powders have been prepared by an ultrahigh- energy ball-milling (UHEBM) process with different milling times (1, 5, 15, 30, and 60 min). Further, their refinement behavior and high-entropy synthesis potential have been investigated. With an increase in the milling time, the particle size rapidly reduces (under sub-micrometer size) and homogeneous mixing of the prepared powder is observed. The distortions in the crystal lattice, which occur as a result of the refinement process and the multicomponent effect, are found to improve the sintering, thereby notably enhancing the formation of a single-phase solid solution (high-entropy). Herein, we present a procedure for the bulk synthesis of highly pure, dense, and uniform FCC single-phase (Fm3m crystal structure) (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide using a milling time of 60 min and a sintering temperature of 1,600oC.

In this study, we report the microstructure and characterization of Ta20Nb20V20W20Ti20 high-entropy alloy powders and sintered samples. The effects of milling time on the microstructure and mechanical properties were investigated in detail. Microstructure and structural characterization were performed by scanning electron microscopy and X-ray diffraction. The mechanical properties of the sintered samples were analyzed through a compressive test at room temperature with a strain rate of 1 × 10−4 s−1. The microstructure of sintered Ta20Nb20V20W20Ti20 high-entropy alloy is composed of a BCC phase and a TiO phase. A better combination of compressive strength and strain was achieved by using prealloyed Ta20Nb20V20W20Ti20 powder with low oxygen content. The results suggest that the oxide formed during the sintering process affects the mechanical properties of Ta20Nb20V20W20Ti20 high-entropy alloys, which are related to the interfacial stability between the BCC matrix and TiO phase.

Lu(Nb,Ta)O4:Eu3+ powders are synthesized by a solid-state reaction process using LiCl and Li2SO4 fluxes. The photoluminescence (PL) excitation spectra of the synthesized powders consist of broad bands at approximately 270 nm and sharp peaks in the near ultraviolet region, which are assigned to the Nb5+-O2− charge transfer of [NbO4]3− niobates and the f-f transition of Eu3+, respectively. The PL emission spectra exhibit red peaks assigned to the 5D0 → 7FJ transitions of Eu3+. The strongest peak is obtained at 614 nm (5D0 → 7F2), indicating that the Eu3+ ions are incorporated into the Lu3+ asymmetric sites. The addition of fluxes causes the increase in emission intensity, and Li2SO4 flux is more effective for enhancement in emission intensity than is LiCl flux. The substitution of Ta5+ for Nb5+ results in an increase or decrease in the emission intensity of LuNb1-xTaxO4:Eu3+ powders, depending on amount and kind of flux. The findings are explained using particle morphology, modification of the [NbO4]3− structure, formation of substructure of LuTaO4, and change in the crystal field surrounding the Eu3+ ions.

조선족 작가 金仁順은 중국 내 ‘치링허우(70后)’를 대표하는 소설가의 한 사람으로 주목을 받고 있다. 그러나 그녀가 희곡 장르에서 뛰어난 재능을 지니고 있다는 사실은 많이 알려져 있지 않다. 그녀는 2004년 소극장용 희곡 <타인(他人)>으로 중국의 문단에 신선한 충격을 던졌고, 2015년에는 『요재지이(聊齋志异)』의 「화피(畵皮)」를 장막희곡으로 만들어 극작가로서의 위상도 굳건히 하였다. 본고에서는 <타인>을 중심으로 그녀의 희곡 창작이 지니는 드라마 기법의 특징과 주제의식을 탐색해 보고자 한다. 그녀의 희곡적 서사 방식은 상식을 뛰어 넘는 대담한 발상과 인물관계의 기발한 설정 등을 통해 극적 충격과 긴장감을 고조시키는 특징이 있다. 그리고 그것은 매우 현실적인 당대를 살아가는 인간 군상들의 실질적인 삶의 행태와 사회적 현상과도 맥락을 같이 한다. 격변하는 중국의 현실을 통해 인간관계가 와해되고 사회적 도덕과 윤리적 질서가 직면한 위기 상황을 매우 희화적으로 묘사하고 있다는 점이다.

Microstructure, electric, and thermal properties of the Ta-Cu composite is evaluated for the application in electric contact materials. This material has the potential to be used in a medium for a high current range of current conditions, replacing Ag-MO, W, and WC containing materials. The optimized SPS process conditions are a temperature of 900oC for a 5 min holding time under a 30 MPa mechanical pressure. Comparative research is carried out for the calculated and actual values of the thermal and electric properties. The range of actual thermal and electric properties of the Ta-Cu composite are 50~300W/mk and 10~90 %IACS, respectively, according to the compositional change of the 90 to 10 wt% Ta-Cu system. The results related to the electric contact properties, suggest that less than 50 wt% of Ta compositions are possible in applications of electric contact materials.

This study was purposed to develope a titanium alloy with low elastic modulus to be used as dental implant. The new titanium alloy was prepared as titanium alloy by adding Tantalum(Ta), Zirconium(Zr), Molybdenum(Mo) into the Ti-X-Y-Z system alloys. In designing the new titanium alloys, two physical variables bond order (Bo) and d-electron orbit energy level (Md) were varied. Mean bond order (  ) was around 2.818∼2.8784eV, and Mean d-electron orbit energy level ( ) was 2.4541~2.4747eV. In the cases of titanium alloys of T-3M and T-3Z, the XRD analysis showed β phase. On the other hand, the phase of α+ β were observed in the T-6Z and T-8Z alloys. Exhibited the highest hardness value to result in T-3Z 309.7Hv alloy Vickers hardness with respect to titanium alloy. In the resulting T-3Z alloy of measuring the elastic modulus value for a titanium alloy exhibited the smallest modulus of elasticity value to 89.81GPa. TEM analysis identified additional feature for T-3Z alloy was detected in addition to the ß-phase.

Cho Yong‐joon･Ha Ji‐hee. 2016. “On the sociolinguistic variation of Korean mirative markers ‘‐kuna’, ‘‐ney’ and ‘‐ta’”. The Sociolinguistic Journal of Korea 24(1). 241~269. The purpose of this paper is to investigate the sociolingustic variation of Korean mirative markers ‐kwuna, -ney and ‐ta, through an experimental method. A 7‐point Likert scale task was adopted for this purpose. The participant’s age was the significant social factor of the observed linguistic variation, but gender does not play any significant role. Particularly, the elderly generation prefers ‐kwuna for a mirative marker, but this tendency declines for young generation. ‐ta seldom functions as a mirative marker for elderly generation, but it gets an independent status as the mirative marker for young generation. The negative semantico‐pragmatic properties of ‐kwuna affects this change.

Transparent and conducting thin films of Ta-doped SnO2 were fabricated on a glass substrate by a pulse laserdeposition(PLD) method. The structural, optical, and electrical properties of these films were investigated as a function ofdoping level, oxygen partial pressure, substrate temperature, and film thickness. XRD results revealed that all the deposited filmswere polycrystalline and the intensity of the (211) plane of SnO2 decreased with an increase of Ta content. However, theorientation of the films changed from (211) to (110) with an increase in oxygen partial pressure (40 to 100mTorr) and substratetemperature. The crystallinity of the films also increased with the substrate temperature. The electrical resistivity measurementsshowed that the resistivity of the films decreased with an increase in Ta doping, which exhibited the lowest resistivity(ρ~1.1×10−3Ω·cm) for 10wt% Ta-doped SnO2 film, and then increased further. However, the resistivity continuouslydecreased with the oxygen partial pressure and substrate temperature. The optical bandgap of the 10wt% Ta-doped SnO2 filmincreased (3.67 to 3.78eV) with an increase in film thickness from 100-700nm, and the figure of merit revealed an increasingtrend with the film thickness.

The microstructure and Cu diffusion barrier property of Ta-Si-N films for various Si and N compositions were studied. Ta-Si-N films of a wide range of compositions (Si: 0~30 at.%, N: 0~55 at.%) were deposited by DC magnetron reactive sputtering of Ta and Si targets. Deposition rates of Ta and Si films as a function of DC target current density for various N2/(Ar+N2) flow rate ratios were investigated. The composition of Ta-Si-N films was examined by wavelength dispersive spectroscopy (WDS). The variation of the microstructure of Ta-Si-N films with Si and N composition was examined by X-ray diffraction (XRD). The degree of crystallinity of Ta-Si-N films decreased with increasing Si and N composition. The Cu diffusion barrier property of Ta-Si-N films with more than sixty compositions was investigated. The Cu(100 nm)/Ta-Si-N(30 nm)/Si structure was used to investigate the Cu diffusion barrier property of Ta-Si-N films. The microstructure of all Cu/Ta-Si-N/Si structures after heat treatment for 1 hour at various temperatures was examined by XRD. A contour map that shows the diffusion barrier failure temperature for Cu as a function of Si and N composition was completed. At Si compositions ranging from 0 to 15 at.%, the Cu diffusion barrier property was best when the composition ratio of Ta + Si and N was almost identical.

수소투과금속인 tantalum과 세라믹 지지체로 Y2O3-stabilized ZrO2 (YSZ)를 이용하여 cermet 수소분리막을 제조하였다. Ta/YSZ cermet 분리막은 헬륨분위기에서의 예비소결과 고진공 하에서의 본소결을 통해 제조하였으며, 소결 및 밀봉 과정에서 발생하는 불순물은 연마를 통해 제거 가능하였다. 이렇게 제조된 분리막은 tantalum의 연속상이 잘 발달된 치밀구조를 보였다. 수소 해리를 위해 팔라듐 코팅을 한 Ta/YSZ 분리막을 이용하여 200∼350°C의 범위에서 수소투과실험을 수행하였다. 300°C에서 분리막에 균열이 형성되었고 Pd 코팅층은 몇 곳이 박리되었다. XRD 결과는 tantalum이 수소와 반응하여 Ta2H가 생성되는 것을 보여주며, Ta2H에 인한 격자 팽창이 분리막의 결함을 초래하였다.

Tantalum nitrides () have been developed to substitute the Cd based pigments for non-toxic red pigment. Various doping elements were doped to reduce the amount of high price Tantalum element used and preserve the red color tonality. Doping elements were added in the synthesizing process of precursor of amorphous tantalum oxides and then Tantalum nitrides doped with various elements were obtained by ammonolysis process. The average particle size of final nitrides with secondary phases was larger than the nitride without the secondary phases. Also secondary phases reduced the red color tonality of final products. On the other hand, final nitrides without secondary phase had orthorhombic crystal system and presented good red color. In other words, in the case of nitrides without secondary phases, doping elements made a solid solution of tantalum nitride. In this context, doping process controlled the ionic state of nitrides and the amount of oxygen/nitrogen in final nitrides affected the color tonality.