• Research in Plant Disease
• /
• v.19 no.1
• /
• pp.55-59
• /
• 2013

The purpose of this experiment was to investigate the development of new spot disease on the leaf and stem of rosemary (Rosmarinus officinalis) in commercial greenhouses at Jeonju and Namwon in Korea. Incidence of target spot on rosemary was higher at the end of the rainy season with high humidity. Those symptoms were black ring spots (3-5 mm in diameter) and withering on green leaves and stems. Conidiophores and conidia were formed on the infected tissue in moist chamber and conidia were shown as the cylindrical and oval types in chain, ranged from 55 to $275{\mu}m$ in length, and 7 to $14{\mu}m$ in width. Conidia with eight to ten pseudosepta were formed on the conidiapore. The optimum growth temperature of isolates was $30^{\circ}C$ on the PDA medium under the dark condition. In the pathogenesis test, the target spot and withering symptoms were appeared on the leaves and stems 3 days after inoculation showing similar symptoms compared to those of in nature. The same fungus was re-isolated from infected lesion, indicating that Corynespora cassiicola caused leaf target spot and twig blight on rosemary. The rDNA ITS nucleotide sequences of the pure cultured isolate from the diseased area on rosemary showed 100% similarity to the sequences of C. cassiicola available in the GenBank database (JQ595296, JQ595297, FJ852715 and AY238606). Therefore, we report that the target spot of leaves and stems in rosemary was caused by C. cassiicola.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.11a
• /
• pp.49.2-49.2
• /
• 2009

투명전극은 디스플레이, 태양전지와 같은 광전자 소자에 필수적이며, 지금까지 개발된 재료 중에는 ITO가 가장 투명하면서 전기전도도가 높고 생산성도 좋기 때문에 투명전극의 재료로 사용하고 있다. ITO는 낮은 비저항(${\sim}10^{-4}{\Omega}cm$) 과 높은 투과율 (~85 %), 상대적으로 넓은 밴드갭 에너지 (3.5 eV) 의특성과 같이 뛰어난 전기적 광학적 특성에 반해서 높은 원자재 가격, 불안정한 공급량 등으로 인한 문제점이꾸준히 제기되고 있다. 따라서 $In_2O_3$:Sn, ZnO:Al, ZnO:Ga, ZnO:F, ZnO:B, TiN 등과 같은 물질들로대체하려는 연구가 활발하게 진행되고 있다. ZnO는 ITO보다원자재의 수급이 원활하기 때문에 원가가 낮으며, 상대적으로 낮은 온도에서도 제작이 가능하다. 또한 화학적으로 안정적이므로 ZnO에 Al, Ga 등의 3족 원소를 도핑함으로써 낮은 비저항의 박막 제작이 가능하고, ITO 박막과 비교하여 etching이 쉬우며 기판과의 접착성이 좋으며, sputtering 공정시 plasma 분위기에서의 안정성이 뛰어나고 박막증착율이 높기 때문에 투명전극으로 적합한 재료이다. 본 연구에서는 cylindrical type의 Aldoping된 ZnO single target을 사용하여 박막 증착 압력의 변화를 주어 유리기판 위에 DC sputtering을 하였다. Fieldemission scanning electron microscope (FESEM)을 통해 ZnO:Al 박막의 표면의 형상과 두께를 확인하였으며, X-ray diffraction (XRD) 분석을 통해 박막의 결정학적 특성을 관찰하였다. 투명전극용 물질로서 ZnO:Al 박막의 적합성 여부를 확인하기 위하여 Van der Pauw 방법을 이용하여 박막의 비저항, 전자 이동도, 캐리어 농도를 측정하였으며, 박막의 기계적 성질 및 표면 접착성을 확인하기 위하여 nano-indentaion 분석을 하였다. 또한 UV-vis spectrophotometer를 이용하여 ZnO:Al 박막의 투과율을 분석하여 투명전극으로의 응용 가능성을 확인하였다.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2293-2298
• /
• 2010

Focused electrospray (FES) deposition method is presented for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. FES ion optics consists of two cylindrical focusing electrodes capped with a truncated conical electrode through which an electrospray emitter passes along the cylindrical axis. A spray of charged droplets is focused onto a sample well on a MALDI target plate under atmospheric pressure. The shape and size distributions of matrix crystals are visualized by scanning electron microscope and the mass spectra are obtained by time-of-flight mass spectrometry. Angiotensin II, bradykinin, and substance P are used as test samples, while $\alpha$-cyano-4-hydroxycinnamic acid and dihydroxybenzoic acid are employed as matrices. FES of a sample/matrix mixture produces fine crystal grains on a 1-3 mm spot and reproducibly yields the mass spectra with little shot-to-shot and spot-to-spot variations. Although FES greatly stabilizes the signals, the space charge due to matrix ions limits the detection sensitivity of peptides. To avoid the space charge problem, we adopted a dual FES/FES mode, which separately deposits matrix and sample by FES in sequence. The dual FES/FES mode reaches the detection sensitivity of 0.88 amol, enabling ultrasensitive of peptides by homogeneously depositing matrix and sample under atmospheric pressure.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.3
• /
• pp.15-21
• /
• 2017

In the active SONAR system, various studies have been carried out to enhance the resolution of a received signal. In order to obtain higher resolution for detecting a bottoming cylindrical object, the design of a planar array for SONAR is investigated in this paper. It is necessary to employ planar structures for SONAR array to obtain narrower beam pattern which gives high resolution. In this study, the transmit frequency of each acoustic transducer, which consists of an array is 13 kHz. For efficient detection of a target of an asymmetric size, the concept of areal angle is applied, which considers resolution according to both azimuth and elevation angles in array design. In the design, the areal angle is first investigated to satisfy the resolution requirements, and then based on the value of areal angles, the azimuth angle and the elevation angle are calculated respectively to design an array.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.1
• /
• pp.30-38
• /
• 2015

In this paper, the design of a compact triple-mode bandpass filter using a high-Q cylindrical dielectric resonator is proposed. In detail, the triple $TE_{01{\delta}}$ modes along three orthogonal axes are used and novel coupling structure in the metallic enclosure is adopted to introduce the coupling between the resonant modes. Due to the cross coupling, the proposed bandpass filter has an asymmetric frequency response with flexible three transmission zeros, one of which can be located very close to the passband edge to provide an extremely sharp skirt characteristic with low insertion loss. The proposed filter is about 60 % miniaturized compared with conventional single-mode dielectric resonator filter. The proposed bandpass filter design is validated by the circuit and 3D EM simulations and measurements compared to the target specifications.

• Progress in Medical Physics
• /
• v.12 no.2
• /
• pp.155-160
• /
• 2001

We developed a new method that the radiation field shape and intensity could be controlled automatically with a insertion of the liquid shielding material box having a rotatable model imitated the 3-dimensional target volume within. The molded box filled with the mercury was mounted to the tray. A acrylic model imitated the 3-dimensional target volume was fixed into the center of the interior of the box. Although the gentry rotate, the acrylic model can be returned to the original direction of the target due to the action of the gravity. The film measurements at the gantry rotation angle 0$^{\circ}$, 45$^{\circ}$, and 90$^{\circ}$, respectively were shown that the radiation intensities were modulated properly and the field shapes were conformed to the target. We verified the dose distribution for our method with a cylindrical acrylic phantom inserted a film within. In the case of the 8-field irradiation, the 80% isodose line was enclosed the target shape properly. This results show the realization of a new intensity-modulated radiation therapy(IMRT).

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.298-302
• /
• 2009

Low power Hall thruster is under development as one of the core technologies for STSAT-3. The Hall thruster has several advantages such as its simple structure, high thrust density and specific impulse etc. Development target values deduced by analyzing requirements are consumed electrical power, thrust, thrust efficiency, and specific impulse of < 300 W, > 10 mN, ~ 35%, and > 1000 s, respectively. In order to achieve the target specifications, two prototype Hall thrusters were developed and compared. To date, thrust and efficiency are 11 mN and 37% under the total power of 290 W with 0.97 mg/s Xe propellent supply.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.8
• /
• pp.441-446
• /
• 2005

This paper presents the changes of acoustic scattering pattern from a single cylinder and two identical cylinders in both theoretical calculations and experimental measurements. Bi-static scattering pattern by single cylinder and two parallel cylinders (length 2m, radius 30mm) was measured in $5m\times5m\times5m$ water tank using high frequency projector (120 kHz) and hydrophone. The results show similar agreement between experiment and theory. In case of single cylinder scattering. omni-directional pattern was observed in backward but there are fluctuations or target strength in forward. Interference between each cylinder's scattering fields produce fluctuations of target strength in all directions of two cylinders.

• Progress in Medical Physics
• /
• v.18 no.2
• /
• pp.93-97
• /
• 2007

This study was designed to evaluate radiosurgery technique using multiple noncoplanar arc therapy with intensity modulated fine MLC shaped photon beam. The stereotactic radiosurgery was performed with 6-MV X-ray beams from a Clinac 21EX LINAC (Varian, Palo Alto, CA, USA) with a MLC-120, which features a full $40{\times}40cm$ field and is the first MLC for general use that offers 0.5 cm resolution for high precision treatment of small and irregular fields. We used a single isocenter and five gantry-couch combinations with a set of intensity modulated arc therapy. We investigated dosimetric characteristics of 2 cm sized spherical target volume with film (X-OMAT V2 film, Kodak Inc, Rochester NY, USA) dosimetry within $25{\times}25cm$ acrylic phantom. A simulated single isocentric treatment using inversely Planned 3D radiotherapy planning system demonstrated the ability to conform the dose distribution to an spherical target volume. The 80% dose level was adequate to encompass the target volume in frontal, sagittal, and transverse planes, and the region between the 40% and 80% isodose lines was $4.0{\sim}4.5mm$ and comparable to the dose distribution of the Boston Arcs. We expect that our radiosurgery technique could be a treatment option for irregular-shaped large intracranial target.

• Structural Engineering and Mechanics
• /
• v.11 no.2
• /
• pp.199-210
• /
• 2001

Axially compressed circular cylinders repeat symmetry-breaking bifurcation in the postbuckling region. There exist stable equilibria with all symmetry broken in the buckled configuration, and the minimum postbuckling strength is attained at the deep bottom of closely spaced equilibrium branches. The load level corresponding to such postbuckling stable solutions is usually much lower than the initial buckling load and may serve as a strength limit in shell stability design. The primary concern in the present paper is to compute these possible postbuckling stable solutions at the deep bottom of the postbuckling region. Two computational approaches are used for this purpose. One is the application of individual procedures in computational bifurcation theory. Path-tracing, pinpointing bifurcation points and (local) branch-switching are all applied to follow carefully the postbuckling branches with the decreasing load in order to attain the target at the bottom of the postbuckling region. The buckled shell configuration loses its symmetry stepwise after each (local) branch-switching procedure. The other is to introduce the idea of path jumping (namely, generalized global branch-switching) with static imperfection. The static response of the cylinder under two-parameter loading is computed to enable a direct access to postbuckling equilibria from the prebuckling state. In the numerical example of an elastic perfect circular cylinder, stable postbuckling solutions are computed in these two approaches. It is demonstrated that a direct path jump from the undeformed state to postbuckling stable equilibria is possible for an appropriate choice of static perturbations.