• Journal of Korean Neurosurgical Society
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• 제47권6호
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• pp.433-436
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• 2010

Objective : Arachnoid cysts (ACs) can be cured by making the definite and wide communication between the cyst and arachnoid space using endoscopy, but often it is impossible only through the usual working-channel (intra-channel) procedures. We discuss and propose a more valuable endoscopic technique with the presentation of our series of cases. Methods : We treated 9 patients with cortical AC in various locations with extra-channel endoscopic techniques. The patients ranged in age from 3 years to 60 years (mean age, 37.2 yrs). The follow-up period ranged from 12 to 26 months (mean follow-up duration, 17.2 months). All patients had large AC compressing the adjacent brain with clinical symptoms or signs. The authors performed extensive fenestration via single burr hole with the aid of endoscope. Being bypassed the rigid endoscope, through the space between the shaft of endoscope and guiding cannula (extra-channel method), fenestration procedures were done in the dry fields. Results : Eight (88.9%) patients had been treated successfully with endoscope. One patient required shunt procedure. Among the eight patients who were treated with endoscopic procedure, 6 patients (66.7%) showed cyst reduction, and two (22.2%) showed disappearance of cyst. Conclusion : We suggest that extra-channel method will be simple and easy to perform using more valuable instruments with wider working area, and may promise better results compared to the conventional intra-channel endoscopic procedures.

• The Plant Pathology Journal
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• 제38권2호
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• 한국전자파학회논문지
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• 제24권1호
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• pp.11-19
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• 2013

본 논문에서는 기생 소자의 커플링 현상을 이용하여 다중 대역 특성을 나타내기 위한 평면형 모노폴 안테나를 설계 및 제작하였다. 제안된 안테나는 단일 공진이 발생하는 사각 패치를 기본으로 다중 대역 특성을 얻기 위해 기생 소자를 삽입하였다. 기생 소자는 안테나 크기의 소형화와 다중 공진 특성을 나타내기 위해 스파이럴 구조를 사용하였으며, 각각의 설계 파라미터들을 이용하여 주파수 특성을 최적화 시켰다. 또한, via-hole을 통해 접지면에 연결된 L자 형태의 공진기를 급전선 양쪽에 삽입함으로써 서비스 대역 이외에 사용되지 않는 주파수 대역을 차단하였다. 사용된 기판은 크기가 $40{\times}60{\times}1mm^3$이고, 비유전율 4.4인 FR-4 기판 위에 설계되었으며, 급전은 임피던스 $50{\Omega}$의 마이크로스트립 선로를 사용하였다. 측정 결과, 1.714~2.496 GHz, 2.977~4.301 GHz, 4.721~6.315 GHz 대역에서 -10 dB 이하의 반사 손실 특성을 나타냈으며, 전방향의 방사 패턴을 나타냈다.

• 천문학회보
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• 제40권2호
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• pp.28.2-28.2
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• 2015

High redshift quasars (z > 5) hold keys to understanding the evolution of the universe in its early stage. Yet, the number of high redshift quasars uncovered from previous studies is relatively small (70 or so), and are concentrated mostly in a limited redshift range (z ~ 6). To understand the early mass growth of supermassive black holes and the final stage of the cosmic reionization, it is important to find a statistically meaningful sample of quasars with various physical properties. Here we present a survey for high redshift quasars at 5 < z < 7. Through color selection techniques using multi-wavelength data, we found quasar candidates and carried out imaging follow-up observations to reduce contaminants. After optical spectroscopy, we discovered eight new quasars. We obtained near-infrared spectra for 3 of these 8 quasars, measured their physical properties such as black hole masses and Eddington ratios, and found that the high redshift quasars we discovered are growing via accretion more vigorous than those of their lower redshift counterparts. We estimated the quasar number densities from our discoveries and compared them to those expected from the quasar luminosity functions in literature. In contrast to the observed number density of quasars at z ~ 5, which agrees with literature, the observed number density at z ~ 7 shows values lower than what is expected, even after considering an extrapolated number density evolution. We conclude that the quasar number density at z ~ 7 declines toward higher redshift, more steeply than the empirically expected evolution.

• Journal of the Korean Wood Science and Technology
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• 제21권1호
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• pp.39-50
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• 1993

The purpose of this study was to describe the micromorphological changes in Korean red pine (Pinus densiflora S. et Z.) wood decayed by a major brown-rot fungus, Lentinus lepideus, using scanning electron microscope and transmission electron microscope. At the end of the 12-week exposure to the fungus in soil block procedure(ASTM 1971), test blocks sustained 5.02% weight loss. The formation of bore hole by hyphae and penetration of hyphae through bordered pit were not observed. Instead, fungal hyphae appeared to penetrate axially tracheid luminar from the the ray cells via cross field pits. Hyphae were mainly found in lignin rich cell corner regions of tracheids, and also extensive degradation of tracheid wall occurred in this region. Extensive degradation of $S_2$ layer occurred without noticeable alteration of the $S_3$ layer, but warty layer and compound middle lamella remained relatively intact. Localized erosion, the characteristic of white rot, was observed in some cell wall and wall components including lignin were found to be decomposed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.267-270
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• 2001

A new small scaling Lateral Trench Insulated Gate Bipolar Transistor (SSLTIGBT) was proposed to improve the characteristics of the device. The entire electrode of the LTIGBT was replaced with a trench-type electrode. The LTIGBT was designed so that the width of device was no more than 10$\mu\textrm{m}$. The latch-up current densities were improved by 4.5 and 7.6 times, respectively, compared to those of the same sifted conventional LTIGBT and the conventional LTIGBT which has the width of 17$\mu\textrm{m}$. The enhanced latch-up capability of the SSLTIGBT was obtained due to the fact that the hole current in the device reaches the cathode via the p+ cathode layer underneath the n+ cathode layer, directly. The forward blocking voltage of the SSLTIGBT was 125 V. At the same size, those of the conventional LTIGBT and the conventional LTIGBT with the width of 17$\mu\textrm{m}$ were 65 V and 105 V, respectively. Because the proposed device was constructed of trench-type electrodes, the electric field in the device were crowded to trench oxide. Thus, the punch through breakdown of LTEIGBT occurred late.

• Transactions on Electrical and Electronic Materials
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• 제2권4호
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• pp.15-18
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• 2001

A new small scaling Lateral Trench Insulated Gate Bipolar Transistor (SSLTIGBT) was proposed to improve the characteristics of the device. The entire electrode of the LTIGBT was replaced with a trench-type electrode. The LTIGBT was designed so that the width of device was no more than 10 ${\mu}{\textrm}{m}$. The latch-up current densities were improved by 4.5 and 7.6 times, respectively, compared to those of the same sized conventional LTIGBT arid the conventional LTIGBT which has the width of 17 ${\mu}{\textrm}{m}$. The enhanced latch-up capability of the SSLTIGBT was obtained due to the fact that the hole current in the device reaches the cathode via the p+ cathode layer underneath the n+ cathode layer, directly. The forward blocking voltage of the SSLTIGBT was 125 V. At the same size, those of the conventional LTIGBT and the conventional LTIGBT with the width of 17 ${\mu}{\textrm}{m}$ were 65 V and 105 V, respectively. Because the proposed device was constructed of trench-type electrodes, the electric field In the device were crowded to trench oxide. Thus, the punch through breakdown of LTEIGBT occurred late.

• 한국레이저가공학회지
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• 제14권4호
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• pp.14-20
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• 2011

The advantage of using lasers for through silicon via (TSV) drilling is that they allow higher flexibility during manufacturing because vacuums, lithography, and masks are not required; furthermore, the lasers can be applied to metal and dielectric layers other than silicon. However, conventional nanosecond lasers have disadvantages including that they can cause heat affection around the target area. In contrast, the use of a picosecond laser enables the precise generation of TSVs with a smaller heat affected zone. In this study, a comparison of the thermal and crystallographic defect around laser-drilled holes when using a picosecond laser beam with varing a fluence and repetition rate was conducted. Notably, the higher fluence and repetition rate picosecond laser process increased the experimentally recast layer, surface debris, and dislocation around the hole better than the high fluence and repetition rate. These findings suggest that even the picosecond laser has a heat accumulation effect under high fluence and short pulse interval conditions. To eliminate these defects under the high speed process, the CDE (chemical downstream etching) process was employed and it can prove the possibility to applicate to the TSV industry.

• Structural Engineering and Mechanics
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• 제85권2호
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• pp.147-161
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• 2023

Based on the ideas of variational differential quadrature (VDQ) and finite element method (FEM), a numerical approach named as VDQFEM is applied herein to study the large deformations of plate-type structures under static loading with arbitrary shape hole made of functionally graded graphene platelet-reinforced composite (FG-GPLRC) in the context of higher-order shear deformation theory (HSDT). The material properties of composite are approximated based upon the modified Halpin-Tsai model and rule of mixture. Furthermore, various FG distribution patterns are considered along the thickness direction of plate for GPLs. Using novel vector/matrix relations, the governing equations are derived through a variational approach. The matricized formulation can be efficiently employed in the coding process of numerical methods. In VDQFEM, the space domain of structure is first transformed into a number of finite elements. Then, the VDQ discretization technique is implemented within each element. As the last step, the assemblage procedure is performed to derive the set of governing equations which is solved via the pseudo arc-length continuation algorithm. Also, since HSDT is used herein, the mixed formulation approach is proposed to accommodate the continuity of first-order derivatives on the common boundaries of elements. Rectangular and circular plates under various boundary conditions with circular/rectangular/elliptical cutout are selected to generate the numerical results. In the numerical examples, the effects of geometrical properties and reinforcement with GPL on the nonlinear maximum deflection-transverse load amplitude curve are studied.

• 동아시아경상학회지
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• 제11권4호
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• pp.11-18
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• 2023

Purpose - By filling the existing research hole and supplying a whole evaluation, this test wants to offer actionable insights for stakeholders navigating the intersection of sustainability and financial prosperity. Ultimately, this study contributes to the evolving speak on ESG, fostering a deeper comprehension of its implications for fostering sustainable economic increase. Research design, data, and methodology - Based on the numerous prior literature, the current study adopts a rigorous and systematic approach to discover the connection between Environmental, Social, and Governance (ESG) performance and its effect on a financial boom. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method is the guiding framework for systematically accumulating and analyzing earlier research studies. Result: The finding of this study indicates that using ESG-pushed innovation, practitioners can force technological advancements inside their respective industries. By combining sustainability with research and improvement tasks, corporations can be leaders in selling economic boom through current, green solutions. Conclusion - In summary, this study concludes that embracing those findings in this study allows practitioners and managers to enhance their organization's easy regular, well-known traditional regular standard overall performance and undoubtedly contribute to a broader financial boom via leveraging the transformative strength of ESG necessities.