• Korean Journal of Materials Research
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• v.8 no.7
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• pp.621-627
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• 1998

The formation of Co-silicide between Co/Zr bilayer on the amorphous and crystalline Si substrates has been investigated. The films of Zr(50$\AA$) and Co(l50$\AA$) were deposited with e-beam evaporation system and were heattreated with the rapid thermal annealing system at the temperatures between 50$0^{\circ}C$ and 80$0^{\circ}C$ with 10$0^{\circ}C$ increments for 30 seconds. The phase identification of Co-silicide was carried out by XRD and the chemical analysis was examined by AES and RBS. The interface morphologies of Co/Zr bilayer films were investigated by cross sectional TEM and HRTEM. $CoSi_2$ was formed epitaxially on the crystalline Si substrate above $700^{\circ}C$ while polycrystalline $CoSi_2$ was grown on the amorphous Si substrate. The formation temperature of Co-silicide on the amorphous Si substrate was about 100 C lower than that on the crystalline Si. The COzSi phase was not identified on the both Si substrates. The formation temperature of first phase of Co-silicide on ColZr bilayer was higher than that on Co mono layer. CoSizlayer formed on the amorphous Si substrate exhibits better uniformity compared to the CoSiz formed on the crystalline substrate. The sheet resistance of CoSiz layer on crystalline Si was lower than that on the amorphous Si at high temperatures.tures.

• Radiation Oncology Journal
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• v.26 no.3
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• pp.135-141
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• 2008

Purpose: To evaluate the clinical outcomes and prognostic factors in retroperitoneal soft tissue sarcomas treated by postoperative radiotherapy. Materials and Methods: The records of 23 patients with retroperitoneal soft tissue sarcomas, who underwent postoperative radiotherapy between 1985 and 2003, were analyzed. The median follow-up period was 77 months (range, $8{\sim}240$ months). A total of 21 patients presented with primary disease, and two patients presented with recurrent disease. Liposarcomas and leiomyosarcomas represented 78% of the diagnosed tumor cases. Moreover, 17 cases were of high grade (grade 2 or 3). The median tumor size was 13 cm (range, $3{\sim}50\;cm$). Complete excision was achieved in 65% of patients. The median radiation dose was 50.4 Gy (range, 45.0 to 59.4 Gy), with conventional fractionation. Results: The 5-year overall, local recurrence-free, and distant metastasis-free survival rates were 68%, 58%, and 71%, respectively. Eleven patients experienced local recurrence, while 9 patients experienced distant metastasis. The most common site for distant metastasis was the liver. A univariate analysis revealed that adjacent organ invasion and age (>60 years) as the significant risk factors contributing to the prediction of poor overall survival. Moreover, multivariate analyses indicated that adjacent organ invasion remained significantly associated with a higher risk of death. In addition, patient age (>60 years) was the other identified risk factor for local recurrence by univariate and multivariate analyses. Except for one case of grade 3 diarrhea, no patient suffered grade 3 or higher complications. Conclusion: Our results were comparable to previous reports in that adjacent organ invasion and patient age (>60 years) were significant predictors of poor survival and tumor recurrence, respectively.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.90-90
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is the first astronomical spectrograph that uses a silicon immersion grating as its dispersive element. IGRINS fully covers the H and K band atmospheric transmission windows in a single exposure. It is a compact high-resolution cross-dispersion spectrometer whose resolving power R is 40,000. An individual volume phase holographic grating serves as a secondary dispersing element for each of the H and K spectrograph arms. On the 2.7m Harlan J. Smith telescope at the McDonald Observatory, the slit size is $1^{{\prime}{\prime}}{\times}15^{{\prime}{\prime}}$. IGRINS has a plate scale of 0.27" pixel-1 on a $2048{\times}2048$ pixel Teledyne Scientific & Imaging HAWAII-2RG detector with a SIDECAR ASIC cryogenic controller. The instrument includes four subsystems; a calibration unit, an input relay optics module, a slit-viewing camera, and nearly identical H and K spectrograph modules. The use of a silicon immersion grating and a compact white pupil design allows the spectrograph collimated beam size to be 25mm, which permits the entire cryogenic system to be contained in a moderately sized ($0.96m{\times}0.6m{\times}0.38m$) rectangular Dewar. The fabrication and assembly of the optical and mechanical components were completed in 2013. From January to July of this year, we completed the system optical alignment and carried out commissioning observations on three runs to improve the efficiency of the instrument software and hardware. We describe the major design characteristics of the instrument including the system requirements and the technical strategy to meet them. We also present the instrumental performance test results derived from the commissioning runs at the McDonald Observatory.

• KSBB Journal
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• v.20 no.4
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• pp.253-259
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• 2005

This study was accomplished using attached $A^2/O$ process that contains nonsurface-modified and surface-modified polyethylene media inside the Anaerobic/Anoxic, Oxic tank, respectively. We could make the hydrophobic polyethylene media have hydrophilic characteristics by radiating ion beam on the surface of the media. The objectives of this study is to investigate the removal efficiencies of the organics and nitrogen when the step feed ratio of raw wastewater into anaerobic and anoxic tank is changed. In this case, we assumed that the denitrification rate can be improved because the nitrifiers in anoxic tank can perform denitrification using RBDCOD instead of artificial carbon sources (for example, methanol, etc.). The wastewater injection rate into anaerobic/anoxic tank was set up by the ratio of 10 : 0, 9 : 1, 8 : 2, 6 : 4, and the results of BOD removal efficiency showed similar trends with $93.3\%,\;92.6\%,\;92.4\%\;and\;91.6\%$, respectively. But the BOD removal efficiency (utilization of the organics) in the anoxic tank was in the order of 9 : 1 $(84.8\%)$, 10 : 0 $(77.0\%)$, 8 : 2 $(75.3\%)$, and 6 : 4 $(61.1\%)$. The T-N removal efficiency was most high when the ratio is 9 : 1 $(67.4\%)$, and other conditions, 10 : 0, 8 : 2, 6 : 4, showed $61.3(\%),\;60.7\%,\;55.5\%$, respectively; the ratio 6 : 4 was found to be lowest T-N removal efficiency, lower than the ratio 9 : 1 by $12\%$. Though the nitrification rate of the ratio 10 : 0, 9 : 1, and 8 : 2 showed similar levels, the ratio 6 : 4 showed considerable inhibition of nitrification, ammonia was the great portion of the effluent T-N. The advantages of this process is that this process is cost-saving, and non-toxic methods than injecting the artificial carbon source.

• Asia pacific journal of information systems
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• v.19 no.3
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• pp.25-49
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• 2009

Advances in technology have resulted in the emergence of new information systems. The convergence of IT and manufacturing sectors has blurred the boundaries among industries. Also, such convergence has become established as a paradigm to build a new area. Especially the convergence of broadcasting and telecommunication, notably in the case of IPTV (Internet Protocol Television), is among the most salient examples of its kind in recent years as a major case of disruptive technology innovation. Despite its much fanfare, such convergence, however, has not fulfilled the expectation; it has not produced positive economic effects while negatively affecting the growth of IPIV. Stakeholders in and around IPIV including telecommunication companies, broadcasting corporations, and government bodies wish to gain control of IPTV under their wings. IPTV has drifted in the midst of conflicts among the stakeholders in and around IPTV, particularly telecommunication and broadcasting organizations in a broad sense. Our empirical research intends to deal with how audiences accept IPTV and how firms provide IPTV services to utilize their resources. Three research questions in this paper include, first, whether Technology Acceptance Model (TAM) can sufficiently explain the acceptance of IPTV as an information system. The second question concerns with empirically testing the playful aspect of IPTV to increase its audience acceptance. Last, but not least, this paper deals with how firms can efficiently and effectively allocate their limited resources to increase IPTV viewers. To answer those three main questions of our study, we collect data from 197 current subscribers of high speed internet service and/or cable/satellite television. Empirical results show that 'perceived usefulness (PU) $\rightarrow$ Intention to use' and 'perceived ease of use (PEU) $\rightarrow$ Intention to use' are significant. Also, 'perceived ease of use' is significantly related to 'perceived usefulness.' Perceived ease of handling IPTV without much effort can positively influence the perceived value of IPTV. In this regard, engineers and designers of IPTV should pay more attention to the user-friendly interface of IPTV. In addition, 'perceived playfulness (PP)' of IPTV is positively related to 'intention to use'. Flow, fun and entertainment have recently gained greater attention in the research concerned with information systems. Such attention is due to the changing features of information systems in recent years that combine the functional and leisure attributes. These results give practical implications to the design of IPTV that reflects not just leisure but also functional elements. This paper also investigates the relationship between 'perceived ease of use (PEU)' and 'perceived playfulness (PP).' PEU is positively related to pp. Audiences without fear can be attracted more easily to the user-friendly IPTV, thereby perceiving the fun and entertainment with ease. Practical implications from this finding are that, to attract more interest and involvement from the audience, IPTV needs to be designed with similar or even more user friendly interface. Of the factors related to 'intention to use', 'perceived usefulness (PU)' and 'perceived ease of use (PEU)' have greater impacts than 'perceived playfulness (PP).' Between PU and PEU, their impacts on 'intention to use' are not significantly different statistically. Managerial implications of this finding are that firms in preparation for the launch of IPTV service should prioritize the functions and interface of IPTV. This empirical paper also provides further insight into the ways in which firms can strategically allocate their limited resources so as to appeal to viewers, both current and potential, of IPTV.

• Progress in Medical Physics
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• v.25 no.1
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• pp.15-22
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• 2014

The IMRT is proper implement to get high dose deliver to tumor as its shape and selective approach in radiation therapy. Since the IMRT is performed as modulated the radiation fluence by the MLC created the open shapes and its irradiation time, the dose of segment of radiation field effects on the cumulated portal dose. The accurate output factor of small and step shape of segment is important to improve the determination of deliver tumor dose as it is directly proportional to dose. This experiment performed with the 6 MV photon beam of Clinac Ex(Varian) from $3{\times}3cm^2$ to $0.5{\times}0.5cm^2$ small field size for collimator jaw in MLC free and/or for MLC open field in fixed collimator jaw $10{\times}10cm^2$ using the CC01 ion chamber, SFD diode, diamond detector and X-Omat film dosimetry. As results of normalized to the reference field of $10{\times}10cm^2$ of MLC, the output factor of $3{\times}3cm^2$ showed $0.899{\pm}0.0106$, $0.855{\pm}0.0106$ for $2{\times}2cm^2$, $0.764{\pm}0.0082$ for $1{\times}1cm^2$ and $0.602{\pm}0.0399$ for $0.5{\times}0.5cm^2$. The output factor of MLC open field has shown a maximum 3.8% higher than that of the collimator jaw open field.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.215-224
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• 1997

Purpose : Stereotactic radiosurgery with external beam irradiation successfully obliterates carefully selected intracranial arteriovenous malformation (AVM) . We Present clinical and radiological long term results after treatment with a single high dose irradiation using a linear accelerator. Materials and Methods : Rrom January 1991 to June 1994, fifteen patients with intracranial AVM were treated in our hospital with the stereotactic radiosurgery using a linear accelerator. The radiation was delivered using a 6 MV linear accelerator. The prescribed doses at the isocenter varied from 1800 to 2500cGy (median : 2000cGy) and were given as a sin91e fraction. The radiation doses at the periphery of the lesion typically corresponded to the 80-90% isodose line. In 14 patients, complete clinical and/or radiological follow-up examination were available. Results : Angiography was available in 13 patients with a follow-up Period from 18 months to 27 months. Of 13 patients, the overall complete obliteration rate was 92.3% (12 patients). This incidence did not correlate with lesion size. Seizure, headache and progressive neurologic deficit were complete recovered. One Patient experienced hemorrhage at 2 months after treatment. One patient developed radiation induced brain edema in the white matter surrounding nidus at 16 months after treatment and showed complete resolution of the edema in MR image obtained at 27 months after treatment. After a follow-up period of up to 6 years, no radiation induced severe late complications occurred. Conclusion : We conclude that stereotactic radiosurgery using a linear accelerator is an effective and safe therapy for symptomatic and surgically inaccessible intracranial AVMs and the results compare favorably to the more expensive and elaborate systems that are currently available for stereotactic radiosurgery.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5259-5264
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• 2014

Background: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Materials and Methods: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose ($D_{Max}$) to rectum was the highest recorded dose at one of these five points. Using the HDRplus 2.6 brachyhtherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded ($D_{2cc}$) for all individual fractions. The mean $D_{2cc}$ of rectum was compared to the means of ICRU rectal point and rectal $D_{Max}$ using the Student's t-test. The mean $D_{2cc}$ of bladder was compared with the mean ICRU bladder point using the same statistical test. The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (${\alpha}/{\beta}$ value of 10 Gy for target, 3 Gy for organs at risk). Results: The total prescribed dose was $77.5Gy{\alpha}/{\beta}10$. The mean dose to the rectum was $4.58{\pm}1.22Gy$ for $D_{2cc}$, $3.76{\pm}0.65Gy$ at $D_{ICRU}$ and $4.75{\pm}1.01Gy$ at $D_{Max}$. The mean rectal $D_{2cc}$ dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48-1.19Gy). The mean EQD2 was $68.52{\pm}7.24Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$, $61.71{\pm}2.77Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$ and $69.24{\pm}6.02Gy_{{\alpha}/{\beta}3}$ at $D_{Max}$. The mean ratio of $D_{2cc}$ rectum to $D_{ICRU}$ rectum was 1.25 and the mean ratio of $D_{2cc}$ rectum to $D_{Max}$ rectum was 0.98 for all individual fractions. The mean dose to the bladder was $6.00{\pm}1.90Gy$ for $D_{2cc}$ and $5.10{\pm}2.03Gy$ at $D_{ICRU}$. However, the mean $D_{2cc}$ dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25Gy). The mean EQD2 was $81.85{\pm}13.03Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$ and $74.11{\pm}19.39Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$. The mean ratio of $D_{2cc}$ bladder to $D_{ICRU}$ bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose. Conclusions: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the $D_{2cc}$ and rectal $D_{Max}$ for $D_{2cc}$. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the $D_{2cc}$.

• Progress in Medical Physics
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• v.16 no.2
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• pp.82-88
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• 2005

In this study, the physical compensator made with the high density material, Cerrobend, and the electronic compensator realized by the movement of a dynamic multileaf collimator were analyzed in order to verify the properness of a design function in the commercial RTP (radiation treatment planning) system, Eclipse. The CT images of a phantom composed of the regions of five different thickness were acquired and the proper compensator which can make homogeneous dose distribution at the reference depth was designed in the RTP. The frame for the casting of Cerrobend compensator was made with a computerized automatic styrofoam cutting device and the Millennium MLC-120 was used for the electronic compensator. All the dose values and isodose distributions were measured with a radiographic EDR2 film. The deviation of a dose distribution was $\pm0.99 cGy\;and\;\pm1.82cGy$ in each case of a Cerrobend compensator and a electronic compensator compared with a $\pm13.93 cGy$ deviation in an open beam condition. Which showed the proper function of the designed compensators in the view point of a homogeneous dose distribution. When the absolute dose value was analyzed, the Cerrobend compensator showed a $+3.83\%$ error and the electronic compensator showed a $-4.37\%$ error in comparison with a dose value which was calculated in the RTP. These errors can be admtted as an reasonable results that approve the accuracy of the compensator design in the RTP considering the error in the process of the manufacturing of the Cerrobend compensator and the limitation of a film in the absolute dosimetry.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.