Antenna sensitivity enhancement using ground shorting pin

This article proposes a design technique to increase the sensitivity of Bluetooth headset antennas. A planar inverted F antenna was designed on the top printed circuit board (PCB) of a two-board PCB. Digital noise was designed as a loop-type source on the bottom PCB, representing general noise derived from digital circuits and digital noise generated from the main cable line. The proposed antenna design was analyzed by means of simulation and verified by means of measurements of a fabricated antenna. The proposed technique increased the measured sensitivity by 2.23 dB.Institute for Information & Communications Technology Promotion (IITP) of Korea Government (MSIT), Grant/Award Number: 2013-0-0040

잔존상아질 후경에 따른 S. mutans의 성견 치수반응에 관한 실험적 연구

치의학과/박사[영문] [한글] 치아 경조직 수복후 치수에 자극을 주는 주된 원인으로서 세균의 존재를 들 수 있다. 이러한 세균의 치수반응에 미치는 영향을 연구하는데 있어, 잔존 상아질 후경(Remaining dentin thickness)이 고려해야할 중요한 요소가 되므로 CARIES METER"(小貴醫器有限會社, 日本)를 사용, 전기 저항치에 따라 후경이 1mm군(50±5KΩ)과 0.5mm군(25±5KΩ)으로 나 누어 5급 와동을 형성한 후, S. mutants실험군은 0.3mm두께의 여과지를 72시간 전에 배양 한 S. mutans(6715, serotype A)의 BHⅠ broth에 침윤시켜 와동저에 놓고 다시 영양소로 새로운 BHⅠ broth를 점적한 여과지를 그 위에 덮은 후, tin foil로 피복하고 IRM"(LD. C aulk Co, U.S.A.)으로 충전하였으며, 대조군은 S. mutans를 넣지 않고, 와동저를 tin foi l만으로 피복한 후, IRM으로 충전하여, 1주, 3주, 8주 경과후 성견 치수 반응을 연구한 결과 다음과 같은 결론을 얻었다. 1. 대조군 0.5mm군의 치수반응은 조상아 세포층의 변화및 충혈에 있어서 대조군 1mm군 에 비하여 더 높은 빈도로 오랫동안 지속되었다. 2. 대조군 1mm군과 S. mutans 실험군 1mm군은 모든 치수반응에서 특징적인 차이가 없는 것으로 나타났다. 3. S. mutans실험군 0.5mm군에서는 급, 만성염증 반응이 나타났으나 대조군 0.5mm군에 서는 염증반응이 나타나지 않았다. AN EXPERIMENTAL STUDY OF THE EFFECT OF S. MUTANS ON THE PULP IN RELATI0N TO THE REMAINING DENTIN THICKNESS Hyung Dong Kim, D.D.S. M.S.D. Department of Dental Science, Graduate School, Yonsei University (Directed by Asso. Prof. Dong Soo Park, D.D.S. M.S.D. Ph.D.) The purpose of this study was to evaluate the pulpal responses of S. mutans (6715, serotype A) in relation to the remaining dentin thickness. The material was consisted of 72 teeth from 6 dogs. CI. V cavities were prepared into 2 different thickness (0.5mm, 1.Omm) of remaining dentin In the control groups, the cavities were filled with filter paper of broth, tin foil, and IRM cement. In the experimental groups, the cavities were filled with filter paper of S. mutans, filter paper of broth tin foil, and IRM cement. The intervals of observation period were 1 week 3 weeks, and 8 weeks respectively after the experiment. The specimens were fixed with 10% formalin and decalcified in 5% nitric acid. All specimens were stained with Hematoxylin - Eosin and examined histopathologically under the microscope, The results were as follow; 1. The changes and congestion of odontob1astic layers were more frequent and lasting in the control group of 0.5mm than in that of 1.Omm remaining dentin thickness. 2. There was no charateristic difference between the control group of 1.0mm and the experimental group of 1.Omm in all pulp responses. 3. Acute and chronic inflammatory cells were seen in the experimental group of 0.5mm, but not seen in the control group Of 0.5mmrestrictio

Compact MIMO antenna for application to smart glasses using T-shaped ground plane

A compact multiple-input multiple-output (MIMO) antenna design for application to smart glasses is proposed in this letter. The proposed MIMO antenna system is comprised of two symmetrical meander antennas operating in the 2.4-GHz wireless local area network band and a T-shaped ground for high isolation. The operation mechanism of the proposed MIMO antennas can be explained using the analysis of a three-port network. Accordingly, the T-shaped ground plane operates as a decoupling structure such that the isolation between antennas can be controlled by tuning the T-shaped ground plane. The reflection coefficient characteristic was measured to be less than -7.5 dB, whereas the isolation obtained was higher than 15 dB. The diversity performance was evaluated using the measured three-dimensional radiation patterns, and the envelope correlation coefficients in the target band were less than 0.1.ICT R&D program of MSIP/IITP, Republic of Korea (ground radiation technique for mobile devices), Grant/Award Number: 2013-0-0040

An Experimental Study on the Surface Roughness of Composite Resins

치의학과/석사[영문] [한글] 복합레진은 치과임상에서 전치부의 심미적 수복재로서 널리 사용되어 오고 있으나 표면 거칠기, 변연누출, 치수에 대한 유해작용, 마모등이 개선 해야 할 과제로 남아있다. 변색 , 이차우식증등은 표면거칠기와 밀접한 관계가 있으며 충전물의 연마를 잘 해줌으로써 변 색과 이차우식중등을 예방할 수 있는 잇점을 갖게된다. 이 논문은 복합레진에 있어서의 충전재료 및 연마방법에 따른 표면거칠기의 효과를 알 아보고자 재래식 복합레진인 Hipol과 microfilled composite resin인 Silar를 충전재료로 하고 White alundum point 와 Sof-Lex disc, Pumice, Rubber polishing point를 연마방 법 및 연마재료로 사용하여 Surtronic3(TAYLOR-HOB SON Co.)과 Profilometer(Bendix Co) 로 측정하여 다음과 같은 결론을 얻었다. 1. 대조군으로 사용한 Mylar matrix 와 접촉, 경화된 표면이 연마한 표면에 비해 더 활 택하였다. 2. Microfilled composite resin인 Silar가 재래식 복합레진인 Hipol보다 연마전 및 연 마후의 표면이 더 활택하였다. 3. 재래식 복합레진인 Hipol에서는 연마후 Sof-Lex disc, White alundum point, Rubber polishing point, Pumice 순으로 활택한 표면을 나타내었으며 White alundum point와 Ru bber polishing point의 평균 표면거칠기는 유의차가 없었다. 4. Microfilled composite resin인 Silar에서는 연마후 Sof-Lex disc, Rubber polishin g point, White alundum point, Pumice순으로 활택한 표면을 나타내었으며 Rubber polish ing point, White alundum point, Pumice의 평균 표면거칠기는 유의차가 없었다. An Experimental Study on the Surface Roughness of Composite Resins Hyong Dong Kim, D.D.S. Department of Operative Dentistry, Graduate School, Yonsei University (Directed by Prof. Dong Soo Park, D.D.S.,M.S.D.,Ph.D.) The purpose of this study was to evaluate the effect of different polishing agents on the surfaces of conventional and microfilled composite resins. Conventional (Hipol ) and microfilled (Silar ) composite resins were selected for this study. 100 cavities were prepared on the acrylic plates, 6mm in diameter and 2mm in depth, and filled with conventional and microfilled composite resins. After polymerization the specimens were polished by using different polishing agents; Sof-Lex disc, White alundum point, Rubber polishing point, Pumice. A Surtronic 3 (TAYLOR-HoBson Co.) and Profilometer (Bendix Co.) were used to record the surface roughness of composite resin specimens. The results were as follows. 1. The surface formed by a Mylar matrix was smoother than any other polished surface. 2. The polished surface of microfilled composite resin were smoother than those of conventional composite resin. 3. Among the experimental groups of conventional composite resin, Sof-Lex disc produced the smoothest surface. Pumice leave a rougher surface than are left with White alundum point and rubber polishing point. There is no statistical difference between White alundum point and Rubber polishing point. 4. Among the experimental groups of microfilled composite resin, Sof-Lex disc also produced the smoothest surface. There are no statistical differences among the other polishing agents.restrictio