• Journal of the Korean Vacuum Society
• /
• v.10 no.3
• /
• pp.321-327
• /
• 2001

Ti-Si-N films obtained by using RF reactive sputtering of targets with various Ti/Si ratios in a $N_2(Ar+N_2)$ gas mixture have been investigated in terms of films resistivity and diffusion barrier performance. The chemical bonding state of Si in the Ti-Si-N film which contained a higher Si content was in the form of amorphous $Si_3N_4$, producing increased film resistivity with increased $N_2$flow rate. Lowering the Si content in the deposited Ti-Si-N film favored the formation of crystalline TiN even at low $N_2$flow rates, and leads to low film resistivity. In addition increasing the N content led to Ti-Si-N films having a higher density and compressive stress, suggesting that the N content in the films appear to be one of the most important factors affecting the diffusion barrier characteristics. Consequently, we proposed the optimum composition in the range of 29~49 at.% of Ti, 6~20 at.% of Si, and 45~55 at.% of N for the Ti-Si-N films having both low resistivity and excellent diffusion barrier performance.

• Korean Journal of Health Education and Promotion
• /
• v.12 no.2
• /
• pp.120-138
• /
• 1995

In order to find smoking status and its related factors for female students, a survey was conducted for 1,045 female students of a women's university in Seoul from 22nd of May to 18th of June, 1995. The results were as follows: 1. Of the 1,045 respondents, 7.4% of them were current smokers and 20.6% of them were ex-smokers. The rate of smoking by the major field of study was 18.5% in art and physical education, 10.6% in liberal art and social science, 1.9% in natural science, and 1.2% in medical science. The rate of smoking by the grade was 4.1% in the freshman, 5.9% in the sophomore, 10.9% in the junior, and 10.0% in the senior grade. 2. 7.2% of respondents experienced first smoking at junior high school, 16.8% at senior high school, 4.1% after high school, and 69.2% at college. 3. The major motivation to start smoking was 'curiosity'(57.9%), 'releasing stress'(21.6%), and 'temptation from friend or senior'(12.0%). 4. The first smoking place was 'entertainment place'(49.6%), 'own room'(20.5%), and 'school '(11.3%). And the first smoking companion was 'friend'(62.3%), 'alone'(19.9%), and 'senior or junior'(5.1%). 5. The average quantity of a daily smoking was 6.16±5.29 cigarettes in current smokers and 31.2% of them had experience to quit smoking at least one or more time. 6. Most of the reasons to quit smoking in ex-smoker were due to 'bad taste '(60.5%), 'health concern'(27.4%) and 'religion'(2.3%). 7. Current smoker and ex-smoker had more positive attitude for the female smoking than nonsmoker. And 76.7% of nonsmokers answered that they would not smoke in the future. 8. Most correspondents(89.8% of nonsmoker, 83.7% of ex-smoker, 80.5% of current smoker) strongly supported the antismoking movement. 9. The major information source in smoking were from 'radio, TV'(51.0%), 'newspaper, magazine'(38.8%) and 'school'(7.7%). 10. The multiple logistic regression analysis showed that the related factors for smoking status were satisfaction of home life, coffee intake, alcohol drinking, sister's smoking, girl friend's smoking, and knowledge about smoking.

• Korean Journal of Health Education and Promotion
• /
• v.21 no.1
• /
• pp.183-195
• /
• 2004

The purpose of this study was to discover the effects on women's health education for college women on their health promotion behaviors and the health related knowledge. The content of women's health education consisted of sex education, smoking, alcohol, exercise, nutrition, diet and stress management. “A Women and Heath” course was provided as an optional full term subject in the years of 2002 and 2003 at C University in G City. Out of 210 students who had chosen this course, 134 had agreed to participate in the research and had answered the same questionnaire which was given before the education and 14 weeks after the course at the last class. The findings are as follows： 1. It was found that the subjects have obtained knowledge mainly from television, radio, the Internet, women's magazines in order before the education. 2. Knowledge related to women"s health origionally scored low(average 1.92 out of 5). However, having completed a course on women and their health, they showed a significant increase of knowledge statistically(t＝26.945, p＝ .001) with average score of 3.48. 3. Health promotion behaviors who had completed the course has statistically significantly increased (t＝6.464, p＝ .001) compared to before the education. The results of this study are that by providing a women's health related course for college women on a regular basis, they could broaden their health related knowledge and become more active in practicing health promotion behaviors. This shows us the need to broaden the curriculum on women's health at the college level so that women have good knowledge and practice the knowledge for the sake of their health throughout their life.

• Journal of Society of Preventive Korean Medicine
• /
• v.2 no.1
• /
• pp.31-43
• /
• 1998

The ultimate goal of national health promotion services is the improvement of quality of life and health longevity through the implementation of health promotion services. The approach strategy for national health promotion summariged as follows: 1) A model for health promotion should be developed by the level of government. 2) Roles and functions between central government and autonomous local governments should be defined to carry out the health promotion services effectively. 3) New manpower for health promotion such as health educator should be trained and activated at hospitals, health centers, industries, school, and related community agencies. 4) School health education should be strengthened in order to teach: various health subject(smoking & alcohol, drug abuse, accident and safe, nutrition, environmental pollution and preservation, population & family planning, personnel hygiene, physical growth, stress, sex education, communicable disease, physical exercise etc) students through appointing health teachers at school base. 5) Health promotion services in industries should be activated using manpower such as health educator, exercise instructor, dietist and counsellor, 6) Health promotion services for the elderly should be activated. 7) Health screening services in the medical insurance and his/her family should be activated for health promotion services. 8) Health education material development center for health promotion should be established and the materials should be made to distribute to related groups, agencies and institutions (health conte.5, hospitals, schools, pharmacies, industries etc). 9) The pilot health promotion center in each automous local governments(large cities, provinces, Guns and Gu level) should be established and operated for community people. 10) The mass media such as TV, radio, newspapers and magazines should be used effectively. 11) Periodic evaluation of health promotion services should be carried out in order to help effective and successful planning for community health promotion in the future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.4
• /
• pp.285-296
• /
• 2005

Reduced pressure chemical vapor deposition technology has been used to study SiGe heterostructure epitaxy and device issues, including SiGe relaxed buffers, proper control of Ge component and crystalline defects, two dimensional delta doping, and their influence on electrical properties of devices. From experiments, 2D profiles of B and P presented FWHM of 5 nm and 20 nm, respectively, and doses in 5×10/sup 11/ ∼ 3×10/sup 14/ ㎝/sup -2/ range. The results could be employed to fabricate SiGe/Si heterostructure field effect transistors with both Schottky contact and MOS structure for gate electrodes. I-V characteristics of 2D P-doped HFETs revealed normal behavior except the detrimental effect of crystalline defects created at SiGe/Si interfaces due to stress relaxation. On the contrary, sharp B-doping technology resulted in significant improvement in DC performance by 20-30 ％ in transconductance and short channel effect of SiGe HMOS. High peak concentration and mobility in 2D-doped SiGe heterostructures accompanied by remarkable improvements of electrical property illustrate feasible use for nano-sale FETs and integrated circuits for radio frequency wireless communication in particular.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.1806-1808
• /
• 2014

We report the successful preparation of gold nanoparticles (Au NPs) using a novel electroreduction process, which is simple, fast, and environmentally friendly (toxic chemicals such as strong reducing agents are not required). Our process allows for the mass production of Au NPs and adequate particle size control. The Au NPs prepared show high biocompatibility and are non-toxic to healthy human cells. By applying radio-frequency (RF) ablation, we monitored the electro-hyperthermia effect of the Au NPs at different RFs. The Au NPs exhibit a fast increase in temperature to $55^{\circ}C$ within 5 min during the application of an RF of 13 MHz. This temperature rise is sufficient to promote apoptosis through thermal stress. Our work suggests that the selective Au NP-mediated electro-hyperthermia therapy for tumor cells under an RF of 13 MHz has great potential as a clinical treatment for specific tumor ablation.

• Journal of the Microelectronics and Packaging Society
• /
• v.15 no.1
• /
• pp.7-18
• /
• 2008

This paper reviews the current development of an ultra-slim SiP for Radio Frequency (RF) application, in which three flip chips, additional passive components and Surface Acoustic Wave (SAW) filters are integrated side-by-side. A systematic investigation is carried out for the design optimization, process and reliability improvement of the package, which comprises several aspects: a design study based on the 3D thermo-mechanical finite element analysis of the packaging, the determination of stress, warpage distribution, critical failure zones, and the figuration of the effects of material properties, process conditions on the reliability of package. The optimized material sets for manufacturing process were determined which can reduce the number of testing samples from 75 to 2. In addition the molded underfilling (MUF) process is proposed which not only saves one manufacturing process, but also improves the thermo-mechanical performance of the package compared with conventional epoxy underfilling process. In the end, JEDEC's moisture sensitivity test, thermal cycle test and pressure cooker tests have also been carried out for reliability evaluation. The test results show that the optimized ultra-slim SiP has a good reliability performance.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.23 no.1
• /
• pp.45-52
• /
• 2003

A number of stress corrosion cracks in turbine rotor disk keyway in power plants have been found and the necessity has been raised to detect and evaluate the cracks prior to the catastrophic failure of turbine disk. By ultrasonic RF signal analysis and using a neural network based on bark-propagation algorithm, we tried to evaluate the location, size and orientation of cracks around keyway. Because RF signals received from each reflector have a number of peaks, they were processed to have a single peak for each reflector. Using the processed RF signals, scan data that contain the information on the position of transducer and the arrival time of reflected waves from each reflector were obtained. The time difference between each reflector and the position of transducer extracted from the scan data were then applied to the back-propagation neural network. As a result, the neural network was found useful to evaluate the location, size and orientation of cracks initiated from keyway.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.315-316
• /
• 2012

반도체와 금속배선의 확산을 방지하기 위한 확산방지막의 필요성이 대두되고 있으며, 이에 대한 연구는 많은 연구 그룹에서 진행중에 있다. 하지만 이러한 연구의 대부분은 전기적, 결정학적 특성에 대하여 안전성 및 재료학적 연구에 국한되어 진행되어졌다. 본 연구그룹은 텅스텐(W)을 질화시킨 W-N 확산방지막에 대하여 연구를 진행하였고, 역시 결정학적 특성에 대한 열적인 안전성을 주로 연구하였으나, 본 연구에서는 W-N 박막의 나노영역에 대한 기계적 특성 평가에 주안점을 두어 W-N 박막의 stress를 nano-indenter 기법을 이용하여 측정하고자하였다. 특히 공정시간의 단축 효과 등의 이유로 박막의 두께를 감소시키는 현재 추세에 맞춰 더 얇은 W-N 확산방지막을 제작하였으며, 이에 대한 분석을 실시하였다. W-N 확산방지막은 Ar(Argonne), $N_2$ (nitrogen) 총유량을 40 sccm으로 고정하여, 질소 유입 조건을 0, 0.5, 1 sccm 으로 변화시켜 Si (silicon) (100) 기판 위에 rf (radio-frequency) magnetron sputter를 이용하여 증착하였다. 이때 W-N 박막의 두께를 30, 100 nm로 달리하여 증착하였으며, 증착된 박막은 질소 분위기 $600^{\circ}C$에서 30분간 열처리하였다. 증착된 시료는 nano-indent를 통하여 표면으로부터 10 nm 부근의 극 표면 물성을 측정하였다. 측정 결과, $N_2$ 가스의 유량을 0.5 sccm 흘려주면서 증착한 W-N 박막이 $N_2$가스를 흘려주지 않은 W 박막과 비교하여 압축응력을 덜 받아 비교적 열에 대하여 안정적임을 확인하였다. 또 30 nm 두께의 W-N 박막이 100 nm 두께의 W-N 박막보다 더 기계적으로 안정적인 상태임을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.235-240
• /
• 2006

Ionospheric scintillation induces a rapid change in the amplitude and phase of radio wave signals. This is due to irregularities of electron density in the F-region of the ionosphere. It reduces the accuracy of both pseudorange and carrier phase measurements in GPS/satellite based Augmentation system (SBAS) receivers, and can cause loss of lock on the satellite signal. Scintillation is not as strong at mid-latitude regions such that positioning is not affected as much. Severe effects of scintillation occur mainly in a band approximately 20 degrees on either side of the magnetic equator and sometimes in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. This paper focuses on estimation of the effects of ionospheric scintillation on GPS and SBAS signals using a software receiver. Software receivers have the advantage of flexibility over conventional receivers in examining performance. PC based receivers are especially effective in studying errors such as multipath and ionospheric scintillation. This is because it is possible to analyze IF signal data stored in host PC by the various processing algorithms. A L1 C/A software GPS receiver was developed consisting of a RF front-end module and a signal processing program on the PC. The RF front-end module consists of a down converter and a general purpose device for acquiring data. The signal processing program written in MATLAB implements signal acquisition, tracking, and pseudorange measurements. The receiver achieves standalone positioning with accuracy between 5 and 10 meters in 2drms. Typical phase locked loop (PLL) designs of GPS/SBAS receivers enable them to handle moderate amounts of scintillation. So the effects of ionospheric scintillation was estimated on the performance of GPS L1 C/A and SBAS receivers in terms of degradation of PLL accuracy considering the effect of various noise sources such as thermal noise jitter, ionospheric phase jitter and dynamic stress error.