• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.239-250
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• 2003

The reliability degradation phenomena in the SiGe hetero-junction bipolar transistor (HBT) are investigated in this review. In the case of the SiGe HBT the decrease of the current gain, the degradation of the AC characteristics, and the offset voltage are frequently observed, which are attributed to the emitter-base reverse bias voltage stress, the transient enhanced diffusion, and the deterioration of the base-collector junction due to the fluctuation in fabrication process, respectively. The reverse-bias stress on the emitter-base junction causes the recombination current to rise, increasing the base current and degrading the current gain, because hot carriers formed by the high electric field at the junction periphery generate charged traps at the silicon-oxide interface and within the oxide region. Because of the enhanced diffusion of the dopants in the intrinsic base induced by the extrinsic base implantation, the shorter distance between the emitter-base junction and the extrinsic base than a critical measure leads to the reduction of the cut-off frequency ($f_t$) of the device. If the energy of the extrinsic base implantation is insufficient, the turn-on voltage of the collector-base junction becomes low, in the result, the offset voltage appears on the current-voltage curve.

• Journal of architectural history
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• v.16 no.2
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• pp.137-152
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• 2007

The purpose of this article is making investigation of the principal composition of the twin-pagodas in Buddhist temple through ornaments of a case preserving relics of Buddha in the east and west pagodas of Gameunsa temple. This research has an important meaning in clarifying that the concept of placement two Buddhas together with lotus sutra, which was only applied to Bulkuksa temple, has been extended to Gameunsa temple. And this observation gave us a clear explanation for the principal composition at the twin-pagodas in Buddhist temple plans. The author obtained the following conclusion from this article : The cases preserving relics of the Buddha for the west and east pagodas are globally in similar form as the type of a royal palace. But the different points between eastern and western can be seen on the existence of Buddhist statues on the base floor, set-up of the gate at railings, and 4 lion statues at a coner of the base floor. In the western pagoda, there are Buddha statues above the base-floor of the cases preserving relics. These Buddha statues are composed of a boy monks and angels with playing music for the praise of the Sakyamuni Buddha lecturing the Lotus sutra at YoungChui Mountain. On the other hand, in the eastern pagoda, Buddha statues on the cases preserving relics are composed of a the Four Devas and monks as a defending God of the nation of Buddha. In the eastern pagoda, one can see something that does not exist in the western pagoda, which is a gate located in railing of a case preserving the relics. This gate described the scene of the Sakyamuni Buddha entering into the pagoda of 7 treasures. In a corner of the case preserving relics in the eastern pagoda, there is another thing which does not exist in the western pagoda. This is a sculpture of a lion which symbols the seat of Lion supporting the Buddha in the Dabotap(the pagoda of 7 treasures). When we observe the form and structure, the descriptions at the railings, the gate, the shrine, the statue of a lion, and the accessories in jewelries, at the cases preserving the relics in the eastern pagoda, one can realize that they have the same combination structures between the ones at Dabotaps in Bulguksa temple and those in China as well as in Japan, all of which represent the Gyun-Bo-Tap-Pum of Lotus Sutra. Among the distribution rules in the twin-pagodas in Buddhist temple, the application of the ideal of lotus was known to be effected only to Bulguksa temple. But from the result of the present article, it is more clearly proved by applying the Gameunsa temple that the distribution theory in the twin-pagodas in Buddhist temple was in fact based on the ideal of lotus.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.109-118
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• 1993

This paper describes the management of knowledge base and optimization models using knowledge-assisted optimization model formulation system UNIK-OPT (UNIfied Knowledge-OPTimization). We will illustrate UNIK-OPT with the case of production scheduling in refinery.

• Review of Korea Contents Association
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• v.10 no.3
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• pp.19-21
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• 2012

한국전통식품포탈은 전통음식의 세계화를 위해 필수적인 컨텐츠 포탈을 통해 새롭게 개편한 한맛한얼 사이트를 운영 중이며, 더불어 앞으로 전통음식 및 한국 고유문화 관련 콘텐츠의 세계화를 위해 어떠한 시스템적 방향성이 있는가에 대한 해답을 제시하고자 함.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.413-439
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• 1995

The purpose of this study was to evaluate the stress distribution developed in the supporting structures by mandibular distal extension removable partial dentures with 2 different direct retainer designs and with or without indirect retainer and abutment splinting. The examined direct retainers on the second bicuspid abutment tooth were Akers clasp and RPA clasp, the indirect retainer was located on the mesial fossa of the first bicuspid, and the first and second bicuspid were splinted in case of tooth splinting. Total 8 cases were compared and analyzed with 3-dimensional finite element method. 150N were applied vertically on the artificial teeth of the removable partial denture, and then stress distribution patterns were analyzed and compared. The results were as follows : 1. The forces transmitted to the abutment tooth were primarily from the occlusal rests. 2. The abutment tooth was displaced distally when the force was applied. The compressive stress was observed at the distal root surface of the abutment tooth and the tensile stress, at the mesial root surface. 3. The denture base was displaced posteriorly and inferiorly when the force was applied. At the more distal portion of the denture base, the greater displacement was observed.And the anterior portion of the major connector was displaced superiorly. 4. The occlusal rest placed on the distal part of the abutment tooth tended to tip the tooth more posteriorly than did one on the mesial part of that tooth. 5. Severe superior displacement was observed at the anterior portion of the major connector in case of removable partial dentures without indirect retainer. 6. In case of tooth-splinting, the stress was distributed through all the root surface of both abuments. In case of no tooth-splinting, the stress was concentrated on the distal root surface of the primary abutment.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.378-381
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• 2014

We studied the pasteurization effect of the microorganism involved in the water, using ion-exchanging filter made of the Radiation Induced Grafted Polymerization. This ion-exchanging filter is made by the graft polymerization of GMA, after irradiation of electron beam to the non-woven filter. Then, we made the ion-exchanging filter (EtA, DEA, SS) applying ion-exchanging base to the GMA filter. As a result, the density of the ion-exchanging base is shown as 2.38 mol/kg in case of EtA, 1.79 mol/kg in case of DEA and 0.75 mol/kg in case of SS. Through this filter made by this method, we measured the pasteurization power of E. coli. We found very high elimination rate such as log 4.65 in case of SS-dial filter, which is higher as 3.00 times in comparison with EtA, and 1.10 times in comparison with DEA. This data show the result is very excellent comparing with 3,000 CFU/ml. of city water treatment basis.

• Transactions of Materials Processing
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• v.32 no.1
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• pp.12-19
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• 2023

The armature core is a part responsible for the skeleton of the steering wheel. Currently, in the case of commercial trucks, the main parts of the parts are manufactured separately and then the product is produced through welding. In the case of this production method, quality and cost problems of the welded parts occur, and an integrated armature core made of magnesium alloy is used in passenger vehicles. However, in the case of commercial trucks, there is no application case and research is insufficient. Therefore, this study aims to develop an all-in-one armature core that simultaneously applies a magnesium alloy material and a die casting method to reduce the weight and improve the quality of the existing steel armature core. The product was modeled based on the shape of a commercial product, and finite element analysis (FEA) was performed through Ls-dyna, a general-purpose analysis program. Through digital image correlation (DIC) and uniaxial tensile test, the accurate physical properties of the material were obtained and applied to the analysis. A total of four types of compression were applied by changing the angle and ground contact area of the product according to the actual reliability test conditions. analysis was carried out. As a result of FEA, it was confirmed that damage occurred in the spoke area, and spoke thickness (t_spoke), base thickness (t_base), and rim and spoke connection (R) were designated as design variables, and the total weight and maximum equivalent stress occurring in the armature core We specify an objective function that simultaneously minimizes . A prediction function was derived using the sequential response surface method to identify design variables that minimized the objective function, and it was confirmed that it was improved by 22%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.661-673
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• 2003

To prevent performance degradation of TCP due to packet losses in the smooth handoff by the route optimization extension of Mobile IP protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers those packets dropped during handoff by forwarding buffered packets at the old base station to the mobile user. But, when the mobile user moves to a congested base station in a new foreign subnetwork, those buffered packets forwarded by the old base station are dropped and TCP transmission performance of a mobile user in the congested base station degrades due to increased congestion by those forwarded burst packets. In this paper, considering the general case that a mobile user moves to a congested base station, we propose a Priority Packet Forwarding to improve TCP performance in mobile networks. In the proposed scheme, without modification to Mobile IP protocol, the old base station marks a buffered packet as a priority packet during handoff. And priority queue at the new congested base station schedules the priority packet firstly. Simulation results show that proposed Priority Packet Forwarding can improve TCP transmission performance more than Implicit Priority Packet Forwarding and RED (Random Early Detection) schemes.

• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.97-102
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• 2009

Purpose: To close anterior cranial base, various types of pedicle flaps have been developed previously. However, the results of those pedicle flaps were not constant. To solve such problem, the author designed bipedicle temporalis-pericranial (BTP) flap based on various types of existing flaps and this study intends to introduce this flap and present clinical application case. Methods: The pedicle of the proposed temporalis-pericranial flap is temporalis muscle. The point of this BTP flap is that because of both sides of the unilateral temporalis-pericranial flap are connected by midline pericranial tissue connected with dense vascular network communicate one another locally, that BTP flap can be safely elevated. The case is a 14 months old male patient of frontoethmoidal encephalomeningocele. Surgery was done in a way that after elevating BTP flap and removing encephalomeningocele, BTP flap was moved intracranially, and to prevent cerebrospinal fluid leakage, anterior cranial base was closed. Results: During 1 year and 6 month outpatient tracking observation, no particular finding like CSF leakage, meningitis or hydrocephalus was observed. Conclusion: The benchmarked BTP flap, effective in the treatment of frontoethmoidal encephalomeningocele, is one of the methods to close intracranium and extracranium.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3196-3202
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• 2012

Post-synthesis is used to synthesize organic hybrid inorganic mesoporous sieves. In this method, the activity and structure of the base sieve are crucial to obtain the definable hybrid materials. The chemical and physical properties of the base can be largely changed either by the final step of its synthesizing processes, by template removal which is accomplished with the oxidative thermal decomposition (burning) method or by solvent extraction method. In this paper we compared two methods for the post-synthesis of organic hybrid MCM-48. When the template was extracted with HCl/alcohol mixture, the final product showed larger pore size, larger pore volume and better crystallinity compared to the case of the thermal decomposition. The reactivity of the surface silanol group of template free MCM-48 was also checked with an alkylsilylation reagent $CH_2=CHSi(OC_2H_5)_3$. Raman and $^{29}Si$ NMR spectra of MCM-48 in the test reaction indicated that more of the organic group was grafted to the surface of the sample after the template was removed with the solvent extraction method. Direct synthesis of vinyl-MCM-48 was also investigated and its characteristics were compared with the case of post-synthesis. From the results, it was suggested that the structure and chemical reactivity can be maintained in the solvent extraction method and that organic grafting after the solvent extraction can be a good candidate to synthesize a definable hybrid porous material.