Pd/Ta2O5/SiC Schottky-diode Hydrogen Sensors Formed by Using Rapid Thermal Oxidation of Ta Thin Films

주성재,최재훈,김성진,김상철 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.9

Pd/Ta2O5/SiC Schottky-diode hydrogen sensors were fabricated, and their hydrogen gas sensing performance was investigated at 573 K and 773 K. Interfacial Ta2O5 films of 120 nm in thickness were formed by using rapid thermal oxidation (RTO) of the sputtered Ta films on SiC. The crystallinity of the Ta and the Ta2O5 films were characterized by using X-ray diffraction (XRD). As-sputtered Ta films on 4H-SiC are composed of β-Ta (body-centered-cubic) and α-Ta (tetragonal), and β-Ta (110) is the dominant orientation. After RTO at 573 K, the Ta films are converted to α-Ta2O5 (orthorhombic). The diode sensors show high sensitivity to H₂ even at the low H₂ concentration of 500 ppm, and the voltage change of the sensor upon H₂ exposure is proportional to the H₂ concentration in the range of 500 ~ 2000 ppm at 573 K. The response voltage ΔV is shown to arise mostly from the change in the series resistance component of the sensor upon H₂ exposure; the main origin of that change is believed to be the Ta2O5 interfacial layer. The response time t90 of the sensor at 573 K was estimated to be approximately 8 s.

Ta-Si-N박막의 조성에 따른 결정구조 및 구리 확산 방지 특성 연구

정병효,이원종,Jung, Byoung-Hyo,Lee, Won-Jong 한국재료학회 2011 한국재료학회지 Vol.21 No.2

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 $N_2/(Ar+N_2)$ 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.

Ta이 첨가된 무연 (Na0.545K0.47)(Nb0.55Ta0.45)O3 세라믹의 온도에 따른 유전 및 압전특성

김진수,임상윤,김명호,박태곤,박종규,송재성 한국물리학회 2013 새물리 Vol.63 No.12

To improve the piezoelectric properties, we prepared Ta-substituted (Na0.545K0.47)(Nb0.55Ta0.45)O3 (NKNT) ceramics by using a solid-state reaction method. We studied the effect of Ta substitution on the dielectric and the piezoelectric properties of the NKNT ceramics. Phase transition temperatures, such as the TO−T (orthorhombic-tetragonal) and the Tc (tetragonal-cubic) transition temperatures, decrease with increasing Ta substitution. In addition, the piezoelectric properties of NKNT were enhanced with increasing Ta substitution. Especially, for the fabricated ceramic, a high piezoelectric coefficient d33 = 284 pC/N was obtained at room temperature. We discuss the enhanced piezoelectric properties related to the formation of the orthorhombic-tetragonal phase and to polymorphic phase transition. 응용특성을 개선하기 위해 Ta을 치환한 (Na0.545K0.47)(Nb0.55Ta0.45)O3 (NKNT)세라믹을 제조하였고, Ta 치환에 따른 유전 및 압전특성을 조사하였다. 제조된 NKNT 세라믹의 삼방정계-정방정계 상전이 (TO−T ) 및 정방정계-입방계 상전이 온도 (Tc)는 NKN 세라믹에 비해 각각감소하였다. 또한 이 NKNT 세라믹의 압전계수 (d33)와 전기기계결합 계수 (k_p)는 증가하였으며, 이에 따라 압전특성은향상되었다. Ta 치환은 삼방정계-정방정계의 상전이 경계 특성 및 결정상형성에 크게 영향을 미치는 것으로 나타났으며, 치환에 따른 유전 및압전특성을 연구하였다.

TA(teaching assistant) 교육 원칙과 방안-대학의 글쓰기 수업을 중심으로-

김남미 한말연구학회 2011 한말연구 Vol.- No.29

In the exemplary class suggested in this thesis, the TA needs to provide total four times of revision and four times of student interview. Both of the procedures are for the TA to give individual feedback to the students based on the analysis and reviews of the students’ writings. The TA takes a role to provide a lesson as well as to assist the professor or lecturer in the class. He or she takes charge of two lessons during which comments are given to all the students on general tendency or problems in their writings. The TA also needs to evaluate each piece of homework and report to the professor in charge. The area a TA is in charge in a class is limited to ‘reading homework’, but within this area the TA is the principal agent to evaluate and give feedback for each student’s homework as well as to provide a lecture. The principles of TA training can be summarized into four items: First, the professors and lecturers need to share the objectives of the study with the TA’s for an efficient education. Second, the TA’s should understand the general concept of teaching methodology to achieve the objectives. Third, the TA’s should be able to set the evaluation standards clearly about the writings of students. Fourth, TA training process needs to be consistently realized as the lessons progress. Lastly, TA’s status should be maintained as the principal agent of feedback as well as a lecturer.

1 eV 이하 에너지 영역에서의 180Ta 동위원소의 중성자공명에 대한 연구

이삼열 한국방사선학회 2014 한국방사선학회 논문지 Vol.8 No.6

본 연구는 자연 속에 미량(존재비: 0.012 %)으로 존재하는 180Ta의 중성자포획 공명에 대하여 포획단면적의 계산치와 측정치를 비교하여 분석하였다. 일반적으로 중성자 공명은 Breit-Wigner식으로 정의되며, 식에는 공명에너지를 중심으로 공명의 폭을 결정하는 다양한 인자들로 구성되어 있다. 그러나 180Ta의 경우 중성자포획단면적과 공명에 대한 정보가 잘 알려져 있지 않고 실험적으로도 측정되어진 예가 현재까지는 없는 것이 현실이다. 따라서 본 실험에서는 천연 Ta속에 포함되어진 180Ta에 의한 중성자 포획에 의해 발생되는 감마선을 관측하여 180Ta의 공명을 분석하고 Mughabghab에 의해서 계산되어진 공명인자를 사용하여 1 eV이하의 에너지에 대한 중성자포획단면적을 계산하고 비교분석하였다. 측정을 위해서 교토대학원자로 실험소의 46-MeV 전자선형가속기를 이용하여 중성자 TOF 방법으로, 에너지 영역 0.003 eV에서 10 eV에 걸쳐 측정하였다. 측정을 위해서는 12개의 Bi4Ge3O12(BGO)섬광체로 구성된 전에너지 흡수검출장치로 180Ta(n,γ)181Ta 반응으로부터 나오는 즉발감마선을 측정하였다. In this study, the neutron capture cross section of 180Ta(natural existence ratio: 0.012 %) obtain by measuring has been compared with the evaluated data for the capture data. In generally, the neutron capture resonance is defined as Breit-Wigner formula. The formula consists of the resonance parameters such as neutron width, total width and neutron width. However in the case of 180Ta, these are very poor experimental neutron capture cross section data and resonance information in below 10 eV. Therefore, in the study, we analyzed the neutron resonance of 180Ta with the measuring the prompt gamma-ray from the sample. And the resonance was compared with the evaluated data by Mughabghab, ENDF/B-VII, JEFF-3.1 and TENDL 2012. Neutron sources from photonuclear reaction with 46-MeV electron linear accelerator at Research Reactor Institute, Kyoto University used for cross section measurement of 180Ta(n,γ)181Ta reaction. BGO(Bi4Ge3O12) scintillation detectors used for measurement of the prompt gamma ray from the 180Ta(n,γ)181Ta reaction. The BGO spectrometer was composed geometrically as total energy absorption detector.

TA집단상담프로그램이 전문계고등학생들의 자아존중감과 의사소통 방식에 미치는 영향

김영임 ( Yeong Im Kim ),이윤주 한국동서정신과학회 2008 동서정신과학 Vol.11 No.1

The aim of this thesis is to develop the TA group counseling program which can enhance the self-esteem of the students in specialized high schools and help them to gain effective communication skills by improving their ways of aggressive communication styles and then to verify its effects. To verify the effects of the TA program I set up hypotheses as follows. First, the experience of the TA group counseling program will have positive effects on the self-esteem of the students in specialized high schools. Second, the experience of the TA group counseling program will have positive effects on the ways in which the students in specialized high schools communicate. To verify the hypotheses of this study I carried out self-esteem and communication skill tests. The subjects were the 24 students from the ○○ specialized high school in Uljugun, Ulsan City, who had low self-esteem and communication skills and volunteered to participate in this program. I divided them into two random groups of 12; one is an experimental group and the other a controlling group. As a self-esteem test tool for the pre-test I used the method developed by Rosenberg(1965) and translated by Jeon Byungje(1974). As a communication skill test tool I used PCI, the method developed to test communication skills of couples by Navran(1996) and translated by Mo Euihoi(2001), and modified in keeping with the high school students. In the case of the TA Program given to the experimental group, after having checked over and analysed various literatures and papers related to the TA program, based on the TA program for youth well-being in Chapter 3 of the book [Psychology of Teenagers and TA Program] co-authored by Je Seokbong. Seok Changhoon (2006), I constructed and developed my own TA program for my subjects. It has been modified and complemented through three consultations with a TA expert, a counseling expert and two educators. I, finally, constructed this program into a total of 8 modules of 120 minutes. Soon after having finished the program I conducted a post-test on both groups with the same self-esteem test tool and communication skill one as the pre-test. I analysed the effects per subscale by conducting ANCOVA, which controls each pre-test score as independent variables and makes post-test scores dependent variables. To complement the limits of the quantitative analysis I analysed the contents of each module Session Evaluation Questionnaire, which lets us know the psychological experiences and changes of individual participants. The results are as follows, First, the pre-test scores related to the self-esteem tests between the experimental group and the controlled group showed meaningful differences(F=23.64, p<.001) but when the differences were controlled the scores between both groups showed meaningful differences(F(1,21)=33.80, p<.001). The results of TA program showed that the post-test scores relating to the self esteem of the experimental group(M=27.42) were higher than those of the controlled group(M=22.33). This shows that the TA program has positive effects on improving the self esteem of the specialized school students. Therefore the first hypothesis that the experience of the TA program will have positive effects on self-esteem of the specialized high school students was supported. Secondly, the pre-test scores related to the communication skills between the experimental group and the controlled group showed meaningful differences(F=7.84, p<.01) but when the difference was controlled the scores between both groups showed meaningful differences(F(1,21)=33.41, p<.001). The post-test score of the experimental group(M=80.67) was higher than that of the controlled group(M=62.92). Therefore, the second hypothesis that the TA program will have positive effects on improving communication skills was supported. To verify the validity of the TA program applied in this study and to complement the limits of quantitative analysis I analysed each SEQ on 4 levels; smoothness, depth, positive-emotion and awareness-emotion. The result is that the score of the 8th module including the whole TA program was the highest out of all of 4 levels. This supports the result that the TA program had positive effects on the self-esteem and communication skills of the students. In the case of contents the score got higher in the order of stroking, ego-state analysis and transactional process. This supports the prior research insisting on the improvement of students` self-esteem through the stroke counseling method of TA. This also matches the prior research that the TA program helps students understand their own and others` personalities and has effects on self-perception and personality improvement. The results of this study show that the TA program has educational availabilities because it had positive effects on the self-esteem and communication skills of the specialized high school students. The TA program met with good results for the students with lower self-esteem and communication skills among the specialized high school students. Therefore, this study has very high values in that it provided empirical data that the TA program is the proven program best suited to help the students adapt to school. I`d like to give some tips for utilizing the results from this study and for succeeding research. First, the TA program might be useful for everyone who wants mental growth and development as well as for students with difficulties. Secondly, it is very useful and important to adjust and arrange time during the TA program. Thirdly, the efficient and suitable methods for students need to be researched in the transactional processing modules. Finally, the program leaders should meet the following qualifications; They should complete an introductory TA course, be open-minded, manage activity-based programs, use various techniques suitable for each situation and in particular lead the program suitably for cognitive levels and for the progress of the students.

Vslue of Squamous Cell Carcinoma Associated Antigen fTA-41 in Patients Iurith Invasive Carcinoma of the Uterine Cervix

조문준,김재성,박승호,남상륜,Cho Moon-June,Kim Jae-Sung,Park Seoung-Ho,Nam Sang-Lyun The Korean Society for Radiation Oncology 1993 Radiation Oncology Journal Vol.11 No.2

We investigated the usefulness of tumor-associated antigen (TA-4) by a radioimmunoasay method in estimating the extent of disease and tracking the clinical course of disease in 58 patients with cervical cancer. According to our results and those of other authors, the normal range of serum TA-4 was arbitrarily taken to be less than 2 ng/ml. The proportion of the pretreatment positive serum TA-4 level of 48 squamous cell carcinoma patients was $60\%.$ And $40\%$ in 5 adenocarcinoma patients. Advanced disease group showed higher incidence of positive serum TA-4 level; $40\%,\;72\%,\;63\%,\;and\;100\%$ in stage I to IV, respectively. And the absolute values of TA-4 were higher in advanced disease. In patients treated with radiation, elevated serum TA-4 level usually declined after 3000 cGy and further dropped to normal range in $44\%$ after 5000 cGy. The positive rate in primary cervical cancer was $59\%,$ (32/54) and $100\%$ (4/4) in recurrent conical cancer. And 15 patients with recurrent or persistent disease during follow-up revealed $80\%$ positive serum TA-4 level. In conclusion, it would be suggested that serial serum TA-4 measurements may be helpful in tracking the clinical course during and after treatment. 자궁경부암 환자의 병변의 범위 및 임상 경과를 추정하는데 TA-4의 유용성을 검토하고자 충남대학교병원에서 자궁경부암으로 진단 받은 58명의 환자를 대상으로 혈청 TA-4치를 RIA 방법으로 측정하여 $\le2\;ng/ml$을 정상 범위로 정하여 다음과 같은 결과를 얻었다. 1) 치료전 평평상피암 환자의 TA-4의 양성율은 $60\%,$ 선암은 $40\%$였다. 2) 병기가 진행될수록TA-4의 양성율및 평균치가 높아서, 양성율 병기 I는 $40\%,$ II는 $72\%,$ III는 $63\%,$ IV는 $100\%$였으며 평균치는 병기 I에서 3.1, II는 6.6, III는 8, IV는17.7 ng/ml였다. 3) 방사선 치료후 혈청내 TA-4치는 감소하여 5000 cGy 조사후 치료전 양성을 보였던 환자의 $44\%$에서 TA-4치 가 정상으로 돌아왔다. 4) 원발성 자궁경부암 환자의 양성율은 $59\%$였으나 지속성 또는 재발성등 치료에 실패한 15명 환자의 양성율은 $80\%$였다. 이상으로 연속적 혈청내 TA-4치의 측정은 자궁경부암 환자의 방사선치료에 따른 임상 경과를 관찰하는데 도움이 될 것으로 사료된다.

The Microwave Properties of Ag(Ta0.8Nb0.2)O3 Thick Film Interdigital Capacitors on Alumina Substrates

이규탁,고중혁 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.2

In this paper, we will introduce the microwave properties of Ag(Ta0.8Nb0.2)O3 thick film planar type interdigital capacitors fabricated on alumina substrates. The tailored paraelectric state of Ag(Ta,Nb)O3 allows the material to be regarded as a part of the family of microwave materials. As thick films formed in our experiment, Ag(Ta,Nb)O3 exhibited extremely low dielectric loss with relatively high dielectric permittivity. This low dielectric loss is a very important issue for microwave applications. Therefore, we investigated the microwave properties of Ag(Ta0.8Nb0.2)O3thick film planar type interdigital capacitors. Ag(Ta0.8Nb0.2)O3 thick films were prepared by a screen-printing method on alumina substrates and were sintered at 1140 C for 2 hrs. The XRD analysis results showed that the Ag(Ta0.8Nb0.2)O3 thick film has the perovskite structure. The frequency dependent dielectric permittivity showed that these Ag(Ta0.8Nb0.2)O3 thick film planar type interdigital capacitors have very weak frequency dispersions with low loss tangents in the microwave range. In this paper, we will introduce the microwave properties of Ag(Ta0.8Nb0.2)O3 thick film planar type interdigital capacitors fabricated on alumina substrates. The tailored paraelectric state of Ag(Ta,Nb)O3 allows the material to be regarded as a part of the family of microwave materials. As thick films formed in our experiment, Ag(Ta,Nb)O3 exhibited extremely low dielectric loss with relatively high dielectric permittivity. This low dielectric loss is a very important issue for microwave applications. Therefore, we investigated the microwave properties of Ag(Ta0.8Nb0.2)O3thick film planar type interdigital capacitors. Ag(Ta0.8Nb0.2)O3 thick films were prepared by a screen-printing method on alumina substrates and were sintered at 1140 C for 2 hrs. The XRD analysis results showed that the Ag(Ta0.8Nb0.2)O3 thick film has the perovskite structure. The frequency dependent dielectric permittivity showed that these Ag(Ta0.8Nb0.2)O3 thick film planar type interdigital capacitors have very weak frequency dispersions with low loss tangents in the microwave range.

正犯背後 正犯理論

李在祥 梨花女子大學校 法學硏究所 2003 法學論集 Vol.7 No.2

Mittelbare Ta"ter ist, wer die Straftat durch einen anderen im Gestalt eines menshlichen Werkzeuges begangen hat. Aus dem fru"her viel verbreiteten Verantwortungsprinzip ist die Mo"glichkeit der mittelbaren Ta"terschaft dort zu vereinen, wo der unmittelbare Handelnde selbst vollverantwortlicher Ta"ter ist. Nach der Lehre vom "Ta"ter hinter dem Ta"ter" ist demgegenu"ber die mittelbare Ta"terschaft auch dann mo"glich, wenn der unmittelbare Handelnde sa"mtliche Strafmerkmale erfu"llt hat. Solcher Fall ist dann als mittelbare Ta"terschaft durch ein volldeliktisch handelndes Werkzeuges zu bereichnen. Die Fa"lle der mittelbaren Ta"terschaft ist in der deutschen Ta"terschaftdogmatik im wesentlichen bei drei Konstellationen anerkannt: ① die Benutsung eines Mittelmannes, der im vermeidbaren Verbotsirrtum die Tat ausfu"hrt. ② die Ta"uschung des Ausfu"hrenden u"ber den konkreten Handlungssinn; hier ist weiter zu unterscheiden zwischen der Ta"uschung u"ber quantifizierbare Unrechts und Schulmasse, der Ta"uschung u"ber quantifizierende Tatunsta"nde und der Hervorrufung eines error in persona. ③ die Verbrechensverwirklichung mittels organisatorischen Machtapparate. Im Rahmen eines organisierten Machtapparates werden die Straftaten von diejenige Person begangen, die nur als ein blosses Ra"dchen im Getriebe eine Rolle spielt und ohne weiteres durch eine andere Person austauschbar ist, die zur Tatbestandsefu"llung immer bereit ist. So kommt trotz voller Verantwortlichkeit des unmittelbaren Ta"ters auch dem hinter ihm stehenden Befehlgeber und Tra"ger des Machtapparates die Tatherrschaft zu. Die Rechtsfigur vom Ta"ter hinter dem Ta"ter ist jedoch nicht mit koreanischer Ta"terschaftsdogmatik vereinbar: (1) Nach der §34 Abs. 1 korStGB ist der mittelbarer Ta"ter nur derjenige, wer einen anderen, der als Ta"ter bestraft oder wegen Fahrla"ssigkeitsdelikte bestraft wird, angestift der Hilfe geleistet hat. Es ist also eine ausdru"ckliche Voraussetzung der mittelbaren Ta"terschaft im korStGB, dass der Tatmittler nicht als vorsa"tzlicher Ta"ter bestraft werden soll. Die mittelbare Ta"terschaft durch ein volldeliktisch handelndes Werkzeug ist nach der §34 Abs. 1 korStGB nicht mo"glich. (2) Der mittelbarer Ta"ter ist nach dem korStGB nicht als Ta"ter sondern Anstifter oder Gehilfe zu bestrafen. Die Begru"ndung der Lehre vom Ta"ter hinter dem Ta"ter liegt in der kriminalpolitische Zweckerreichung, dass ein bei der Tatausfu"hrung eine wesentliche Rolle spielende Hontermann als Ta"ter bestraft werden zu ko"nnen. Im Rahmen der koreanischen Straftrechtsdogmatik zur mittelbaren Ta"terschft ist jedoch der eigentliche Zweck dieser Lehre nicht erreichen.

Optical Properties and X-ray Photoelectron Spectroscopy Study of Reactive-sputtered Ta-N Thin Films

이광배,이경행 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

The optical properties and an X-ray photoelectron spectroscopy (XPS) analysis of amorphous Ta- N thin films were investigated. Ta-N thin films reactively sputtered at N2 partial pressures (P(N2)) < 0.2 mTorr had the [111]-axis preferred orientation with a cubic δ-TaN phase while amorphous Ta- N thin films were obtained for P(N2) >= 0.2 mTorr. The band gap of the amorphous Ta-N thin films increased from 1.4 eV to 3.6 eV with increasing P(N2) from 0.3 mTorr to 5.0 mTorr. For P(N2) < 0.3 mTorr, the chemical binding states of Ta-N are predominant as the TaN compound. Otherwise, in the chemical states of Ta-N, N-rich metastable phases similar to those of Ta2O5 increase up to a 50% fraction of Ta-N bonding states with increasing P(N2) and are closely related to the optical transparency of amorphous Ta-N thin films. The optical properties and an X-ray photoelectron spectroscopy (XPS) analysis of amorphous Ta- N thin films were investigated. Ta-N thin films reactively sputtered at N2 partial pressures (P(N2)) < 0.2 mTorr had the [111]-axis preferred orientation with a cubic δ-TaN phase while amorphous Ta- N thin films were obtained for P(N2) >= 0.2 mTorr. The band gap of the amorphous Ta-N thin films increased from 1.4 eV to 3.6 eV with increasing P(N2) from 0.3 mTorr to 5.0 mTorr. For P(N2) < 0.3 mTorr, the chemical binding states of Ta-N are predominant as the TaN compound. Otherwise, in the chemical states of Ta-N, N-rich metastable phases similar to those of Ta2O5 increase up to a 50% fraction of Ta-N bonding states with increasing P(N2) and are closely related to the optical transparency of amorphous Ta-N thin films.