• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.10-10
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• 2008

Silicide is inevitable for CMOSFETs to reduce RC delay by reducing the sheet resistance of gate and source/drain regions. Ni-silicide is a promising material which can be used for the 65nm CMOS technologies. Ni-silicide was proposed in order to make up for the weak points of Co-silicide and Ti-silicide, such as the high consumption of silicon and the line width limitation. Low resistivity NiSi can be formed at low temperature ($\sim500^{\circ}C$) with only one-step heat treat. Ni silicide also has less dependence of sheet resistance on line width and less consumption of silicon because of low resistivity NiSi phase. However, the low thermal stability of the Ni-silicide is a major problem for the post process implementation, such as metalization or ILD(inter layer dielectric) process, that is, it is crucial to prevent both the agglomeration of mono-silicide and its transformation into $NiSi_2$. To solve the thermal immune problem of Ni-silicide, various studies, such as capping layer and inter layer, have been worked. In this paper, the Ni-silicide utilizing Pd stacked layer (Pd/Ni/TiN) was studied for highly thermal immune nano-scale CMOSFETs technology. The proposed structure was compared with NiITiN structure and showed much better thermal stability than Ni/TiN.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.5 s.112
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• pp.69-82
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• 2005

These studies were carried out (1) to investigate the growth characteristics of Sedum album L. in the field, (2) to propose a suitable shallow peen roof system for this plant, and (3) to evaluate plant growth in the proposed system over the long term. The growth characteristics, such as morphological properties, growth habit, shade tolerance, and flowering, were surveyed. In experimental shallow green-roof systems, the effects of drainage type, substrate type, and soil depth on plant growth were investigated. Then drought tolerance was investigated. After planting Sedum album L. in the proposed system survival rate, cover, and resistance to insects, heal and cold were evaluated for about 2 years. The results of these studies are summarized below. 1. In the field, the aboveground part of Sedum album L. did not die back during the winter. Plant height was 4$\sim$7 cm. Roots were distributed to a depth of 5$\sim$7 cm. Sedum album L. is a compact ground-cover plant that spreads vigorously. Shading condition of less than $30\%$ of full sunlight didn't cause any trouble, but shading conditions above $87\%$ made the shape of the shoots and leaves abnormal. The plant bloomed from June to August and had a rather large compound umbel of white, star-shaped flowers. 2. Two systems, a drainage-blend-10 cm soil depth and a reservoir$\cdot$drainage-blend-15 cm soil depth, performed best in terms of cover, fresh weight, and dry weight. The first has an advantage for green roofs because it is lighter than the latter. 3. In drainage-blend-10 m soil depth and modified reservoir · drainage-blend-10 cm soil depth system no plants died for about 4 months after stopping the irrigation. The visual quality of the latter system was above 5 for 4 months and that of the former was under 5 after 2 months. In the field, however, the drought tolerance of Sedum album L. grown in the former would be enough to withstand the dry season. Considering the urban ecosystem and the importance of healthy growth the modified reservoir $\cdot$ drainage-blend-10 cm soil depth system was finally recommended. This system was composed of a 4 cm thick drainage layer and drain outlets placed at a height of 2.5 cm. 4. In the proposed system, the survival rate was $100\%$, and there was no injury induced by insects and heat. The leaf density decreased a little in winter. Cover increased throughout the year. Sedum album L. was planted with a cover of 72$cm^{2}$ on 3 April 2003; on 16 June 2003 and 15 June 2004, cover was $132.66\pm$5.87 $cm^{2}$(1.8 times) and $886.98\pm$63.51 $cm^{2}$(12.3 times), respectively.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.10
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• pp.1-8
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• 1999

In this paper, we have studies the transport mechanism and origin of SILC for the various thickness of wet oxide. Also, SILC characteristics of $N_2O$ annealed oxide was included in this study. We made the flash memory cell with $N_2O$ annealed oxide of 60Athick under $0.25{\mu}m$ design rule, and measured the characteristics of the cell. As a result, we have found that the origin of SILC is due to the trap formed inside of the oxide layer by electrical stress. And we reached the conclusion that the transport mechanism of SILC is ruled by the modified F-N tunneling if the electric field is lower than 8MV/cm or typical F-N tunneling if the electric field is higher than 8MV/cm. We could also confirm the fact that $N_2O$ annealed oxide of 60Athick have an improved resistance effect against SILC. In case that we apply $N_2O$ annealed oxide of 60Athick to the flash memory, we could confirm $10^6$ times endurance and more than 10 years drain disturb, and could get 8V programmable flash memory characteristics.

• Journal of IKEEE
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• v.11 no.4
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• pp.152-157
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• 2007

AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated and the effect of ${N_2}O$ plasma on the electrical characteristics of the devices was investigated. The HEMT exposed to ${N_2}O$ plasma formed by 40 W of RF power in a chamber with pressure of 20 mTorr at a temperature of $200^{\circ}C$, exhibited a reduction of gate leakage current from 246 nA to 1.2 pA by 10 seconds treatment. The current between the two isolated active regions reduced from 3 uA to 7 nA and the sheet resistance of the active layer was lowered also. The variations of electrical characteristics for HEMT were occurred within a short time expose of 10 seconds and the successive expose did not influence on the improvements of gate leakage characteristics and conductivity of the active region. The reduced leakage current level was not varied by successive $SiO_2$ deposition and its removal. The transconductnace and drain current of AlGaN/GaN HEMTs were increased also by the expose to the ${N_2}O$ plasma.

• Archives of Plastic Surgery
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• v.44 no.6
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• pp.516-522
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• 2017

Background Implant-based breast reconstruction is being performed more frequently, and implants are associated with an increased risk of infection. We reviewed the clinical features of cases of implant infection and investigated the risk factors for breast device salvage failure. Methods We retrospectively analyzed 771 patients who underwent implant-based breast reconstruction between January 2010 and December 2016. Age, body mass index, chemotherapy history, radiation exposure, and smoking history were assessed as potential risk factors for postoperative infection. We also evaluated the presence and onset of infection symptoms, wound culture pathogens, and other complications, including seroma, hematoma, and mastectomy skin necrosis. Additionally, we examined the mastectomy type, the use of acellular dermal matrix, the presence of an underlying disease such as hypertension or diabetes, and axillary node dissection. Results The total infection rate was 4.99% (58 of 1,163 cases) and the total salvage rate was 58.6% (34 of 58). The postoperative duration to closed suction drain removal was significantly different between the cellulitis and implant removal groups. Staphylococcus aureus infection was most frequently found, with methicillin resistance in 37.5% of the cases of explantation. Explantation after infection was performed more often in patients who had undergone 2-stage expander/implant reconstruction than in those who had undergone direct-to-implant reconstruction. Conclusions Preventing infection is essential in implant-based breast reconstruction. The high salvage rate argues against early implant removal. However, when infection is due to methicillin-resistant S. aureus and the patient's clinical symptoms do not improve, surgeons should consider implant removal.

• International Journal of Highway Engineering
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• v.6 no.1 s.19
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• pp.1-11
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• 2004

This study tries to propose the most effective pavement texture method through the performance evaluation of variable texture methods. Noise 2$\sim$3dB is reduced in the section of uniform space 18m longitudinal tinning. This result is proved by comparing the magnitude of noise in two sections. The noise of 26mm longitudinal firming section is greater than that of 18mm section by 2$\sim$3dB(A). The skid resistances measured in all test section show the reasonable results. The roughness or all the test sections satisfies AASHTO roughness standard (PrI 16cm/km). The result or questionnaire survey about driving quality shows that the longitudinal tinning is the most effective method. As the result of a visual measurement, it is proved that the section applied uniform space 26mm longitudinal tinning and the general section applied uniform space 26mm transverse tinning could drain water effectively. As the result of analysis with the ranking method, the 18mm longitudinal tinning in selected as one of the most effective tinning methods. In addition, 26mm longitudinal tinning, random space transverse tinning, and transverse drag are selected in order.

• Land and Housing Review
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• v.2 no.2
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• pp.163-170
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• 2011

Individual Vacuum Pressure Method (IVPM) is a soft ground improvement technique, in which a vacuum pressure can be directly applied to the vertical drain board to promote consolidation and to strengthen the soft ground. This method does not require surcharge loads, different to embankment or pre-loading method. In this study, the ground improvement efficiency of Individual Vacuum Pressure Method was estimated when suction pressure increases step by step(-20, -40, -60, -80kPa) with different periods. During Individual Vacuum Pressure Method process, surface settlement and pore pressure were monitored, and cone resistance as well as water content were also measured after the completion of Individual Vacuum Pressure Method treatment. From the results, optimum duration of each step of vacuum pressure was determined, and the settlement was calculated using FEM numerical analysis.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.7-24
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• 1977

This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.