선로결합에 의한 쌍방향 능동 위상차 배열 안테나의 동작특성 향상

최영규,김기래,Choi, Young-Kyu,Kim, Ki-Rae 한국정보통신학회 2008 한국정보통신학회논문지 Vol.12 No.3

쌍방향 선로결합형 위상차 배열 발진기 결합계를 구성하고, (1) 쌍방향 주파수제어 방식, (2) 단방향 주파수 제어방식, (3) 쌍방향 주입위상 제어방식 등 3가지 방식에 대하여 구동실험을 하였다. 시험 제작한 발진기에 구형 패치 안테나를 부착하여 2요소 능동안테나를 제작, 안테나 사이를 전송선로로 결합하여 어레이를 구성하고 결합 위상과 전송선로 길이와의 관계를 측정하였다. 전송선로로 결합된 능동 위상차 배열안테나의 주사각도에 따른 방사전력을 측정한 결과, (1)의 방식에서 빔의 방사방향은 약$-9.8^{\circ}$에서 $+9.8^{\circ}$까지 $19.6^{\circ}R, 위상차는 $-0.31{\pi}$에서 $-0.36{\pi}$까지 (2)의 방식에서 빔의 방사방향은 약 $-3.8^{\circ}$에서 $+17^{\circ}$까지 $20.8^{\circ}$, 위상차는 $-0.085{\pi}$에서 $-0.65{\pi}$까지, (3)의 방식에서 빔의 방사방향은 약 $-17^{\circ}$에서 $+16^{\circ}$까지 $33^{\circ}$, 위상차는 $-0.63{\pi}$에서 $-0.59{\pi}$까지 변하여 모두 위상차 배열동작이 가능함을 확인하였다. In order to increase the coupling efficiency of the power and phase of the active phase array antenna, we have fabricated the active phased-array antenna which is coupled by the transmission line, and investigated the relationship between the length of the coupling transmission line and coupling power and phase. The following three types of driving method - (1) giving the frequency difference between the two active antenna, (2) applying the input signal to the one side of the two antennas, and changing the eigen frequency of the other side antenna, (3) appling the different phase inputs to the active antennas was investigated. The experimental results showed that the interval of the antenna elements has not affected the power and the phase of the antenna.

논문 : 기계적 성질 ; 2 상 Ti-6Al-4V 합금의 크리프및 초소성 변형에 대한 미세조직학적 고찰

김지식 ( J. S. Kim ),김진홍 ( J. H. Kim ),박찬경 ( C. G. Park ),이종수 ( C. S. Lee ) 대한금속재료학회 ( 구 대한금속학회 ) 1998 대한금속·재료학회지 Vol.36 No.7

A study has been made to investigate the microstructural aspects of phase/grain boundary sliding and its accommodation mechanism/mode during superplastic deformation in a two phase Ti-6Al-4V alloy. Tensile tests have been carried out at 600℃ and 900℃ using specimens of 3.2 and 10.6 μm grain sizes. Deformed microstructures have been analysed by transmission electron microscopy to understand the deformation mode, accommodation mechanism, and relative sliding rate of the phase boundary and grain boundaries, In the fine grain (3.2 μm) microstructure deformed at 600℃ and 900℃, dislocations were homogeneously distributed in the α-phase with low density implying that deformation mode follows an iso-stress model. However, the coarse-grain specimens (10.6 μm) reveal the planar slip behavior in the α-phase which indicates that the deformation mode is of a mixed type between iso-stress and iso strain rate mode. It is also considered that accommodation for phase/grain boundary sliding in the α and β phase mainly results from a dislocation activated process, The generation of boundary dislocations is more concentrated along α/β phase boundaries than the α/α grain boundaries, which confirms the sliding resistance of α/β < α/ α.

Shift robust control during inertia phase for random disturbance load

Guoxiang Cao,Anlin Wang,Xiaotian Liu,Donghuan Xu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1

The automatic transmission of earthmoving machinery generally has problems of shifting shock and poor control robustness. Low-frequency high-energy random loads and large-space model uncertainties are the main causes of these problems. Therefore, we considered a type of wheel loader automatic transmission as the research object and propose a robust control method for the shifting inertia phase of the earthmoving machinery automatic transmission. The control method includes a robust controller b K , a disturbance compensation controller d K and a feedforward compensator f K . The robust controller b K is designed by μ synthesis method to resist the uncertainties of parameters and structure and guarantee the output speed to track the reference input. A load dynamic estimation method for random disturbance load of automatic transmission is proposed, which improves the compensation effect of disturbance compensation controller d K . The feedforward compensator f K is used to eliminate the influence of the reference input on the system. The above control methods were applied to the whole machine simulation platform of a certain type of wheel loader, and the random disturbance load of the measured under real working conditions was taken as input load. Under the conditions of no-load, half-load and full load, the control method has good smoothness and strong robustness. This paper has reference value for solving the inertial phase shift robust control of transmission under random disturbance load.

High Resolution Transmission Electron Microscopy Observations on Sintering Processes in KNbO₃ Ceramics

Lee, Hwack Joo,Kim, Young Heon,Ryu, Hyun,Cho, Yang-Koo,Nahm, Sahn Korean Society of Microscopy 2017 Applied microscopy Vol.47 No.3

A homogeneous $KNbO_3$ (KN) phase was formed by sintering at $1,040^{\circ}C$ for 1 hour, without formation of the $K_2O$-deficient secondary phase even though suffering the minor loss of $K_2O$. KN liquid phase was formed during sintering and abnormal grain growth occurred in this specimen. The detailed microstructural observations on KN during sintering were carried out using high resolution transmission electron microscopy. The ledged structures were found at the KN grain boundary and the abnormal grain growth was performed by the lateral migration of these ledges in the presence of the liquid phase. The liquid pockets were found in the KN grains. They have various external shapes mainly due to the kinetic factors. They have atomically flat interfaces with some ledges with one atomic height. The slight deficient $K_2O$ by evaporation might somewhat reduce the melting point of KN from the reported at $1,058^{\circ}C$. The liquid pockets play an important role in supplying the liquid phase during the abnormal grain growth in the sintering process of KN ceramics.

Double Random Phase Encryption using Orthogonal Encoding for Multiple-Image Transmission

이인호,조명진 한국광학회 2014 Current Optics and Photonics Vol.18 No.3

In this paper we extend double random phase encryption (DRPE) using orthogonal encoding from single-image transmission to multiple-image transmission. The orthogonal encoding for multiple images employs a larger Hadamard matrix than that for a single image, which can improve security. We provide a scheme for DRPE with an orthogonal codec, and a method for orthogonal encoding/decoding for multiple-image transmission. Finally, simulation results verify that the DRPE using orthogonal encoding for multiple images is more secure than both the conventional DRPE and the DRPE using orthogonal encoding for a single image.

유체를 이용하여 위상응답을 제어하기 위해 잉크젯 프린팅으로 구현한 미세유체채널 복합 좌·우향 전송선로

최성진(Sungjin Choi),임성준(Sungjoon Lim) 한국전자파학회 2015 한국전자파학회논문지 Vol.26 No.1

본 논문은 미세유체채널에 채워진 유체를 이용하여 위상응답을 제어하는, 잉크젯 프린터로 인쇄된 미세유체채널 복합 좌·우향 전송선로(CRLH TL: Composite Right/Left Handed Transmission Line)를 제안한다. 제안된 CRLH TL은 종이 위에 은 나노입자 잉크를 이용하여 인쇄되었으며, Poly Methyl Methacrylate(PMMA)에 레이저 식각을 이용하여 제작된 미세유체채널은 잉크젯 프린터로 인쇄된 접착물질인 SU-8을 이용하여 CRLH TL 위에 부착되었다. 제안된 CRLH TL은 미세유체채널에 채워진 유체에 따라서 위상응답을 변화시킬 수 있으며, 미세유체채널에 각기 다른 유체가 흐를 때, 900 MHz에서 ?10 dB 이하의 반사계수를 유지한 상태로 위상 지연, 0° 위상, 위상 앞섬 특성을 모두 나타낼 수 있음을 확인하였다. 제안된 CRLH TL의 성능은 시뮬레이션 결과와 측정 결과를 통하여 성공적으로 증명되었다. In this paper, a novel fluid controlled phase tunable line using inkjet printed microfluidic composite right/left-handed(CRLH) transmission line(TL) is proposed. A CRLH-TL prototype has been inkjet-printed on a paper substrate using silver nano particle ink. In addition, a laser-etched microfluidic channel in poly methyl methacrylate(PMMA) has been integrated with the CRLH TL using inkjetprinted SU-8 as a bonding material. The proposed TL provides excellent phase-tuning capability that is dependent on the different fluidic materials used. As the fluid is changed, the proposed TL can have negative-phase, zero-phase, and positive-phase characteristics at 900 MHz and reflection coefficient is maintained to below ?10 dB. The performance of the proposed TL is successfully validated using simulation and measurement results.

Effect of Pd Addition on the Microstructure of Ti-30Nb Alloy

P. Żywicki,D. H. Ping,T. Abe,H. Garbacz,Y. Yamabe-Mitarai,K. J. Kurzydłowski 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.4

The effect of Pd addition on deformation mechanisms, phase transitions and twinning has been extensively investigated in as-cast β-type Ti-30Nb (wt%) alloy using electron backscattered diffraction and transmission electron microscopy techniques. The addition of Pd resulted in refinement of the metastable ω phase. The {112}<111>-type twinning was found to strongly depend on the size of the ω particles. No β phase twins were observed in the binary alloy with larger ω particles. In the ternary alloy with much finer ω particles, {332}<113> and abundant {112}<111>-type twins were detected. On the contrary, the volume fraction of stress-induced α" martensite in the binary alloy was higher than that in the ternary one. Based on the analysis of phase diagrams and Gibbs free energy calculations, such complex phase transition and twinning phenomena have been explained in terms of relative phase stability between the ω particles and the β matrix.

Surpassing Tradeoffs by Separation: Examples in Transmission Line Resonators, Phase-Locked Loops, and Analog-to-Digital Converters

Sun, Nan,Andress, William F.,Woo, Kyoung-Ho,Ham, Don-Hee The Institute of Electronics and Information Engin 2008 Journal of semiconductor technology and science Vol.8 No.3

We review three examples (an on-chip transmission line resonator [1], a phase-locked loop [2], and an analog-to-digital converter [3]) of design tradeoffs which can in fact be circumvented; the key in each case is that the parameters that seem to trade off with each other are actually separated in time or space. This paper is an attempt to present these designs in such a way that this common approach can hopefully be applied to other circuits. We note reader that this paper is not a new contribution, but a review in which we highlight the common theme from our published works [1-3]. We published a similar paper [4], which, however, used only two examples from [1] and [2]. With the newly added content from [3] in the list of our examples, the present paper offers an expanded scope.

Surpassing Tradeoffs by Separation: Examples in Transmission Line Resonators, Phase-Locked Loops, and Analog-to-Digital Converters

Nan Sun,William F. Andress,Kyoungho Woo,Donhee Ham 대한전자공학회 2008 Journal of semiconductor technology and science Vol.8 No.3

We review three examples (an on-chip transmission line resonator [1], a phase-locked loop [2], and an analog-to-digital converter [3]) of design tradeoffs which can in fact be circumvented; the key in each case is that the parameters that seem to trade off with each other are actually separated in time or space. This paper is an attempt to present these designs in such a way that this common approach can hopefully be applied to other circuits. We note reader that this paper is not a new contribution, but a review in which we highlight the common theme from our published works [1-3]. We published a similar paper [4], which, however, used only two examples from [1] and [2]. With the newly added content from [3] in the list of our examples, the present paper offers an expanded scope.

Fault Location for Incomplete-Journey Double-Circuit Transmission Lines on Same Tower Based on Identification of Fault Branch

Wang, Shoupeng,Zhao, Dongmei,Shang, Liqun The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

This paper analyses the characteristics of incomplete-journey double-circuit transmission lines on the same tower formed by single-circuit lines and double-circuit lines, and then presents a fault location algorithm based on identification of fault branch. With the relationship between the three-phase system and the double-circuit line system, a phase-mode transformation matrix for double-circuit lines can be derived. Based on the derived matrix, the double-circuit lines with faults can be decoupled, and then the fault location for an incomplete-journey double-circuit line is achieved by using modal components in the mode domain. The algorithm is divided into two steps. Firstly, the fault branch is identified by comparing the relationships of voltage amplitudes at the bonding point. Then the fault location, on the basis of the identification result, is calculated by using a two-terminal method, and only the fault distance of the actual fault branch can be obtained. There is no limit on synchronization of each terminal sampling data. The results of ATP-EMTP simulation show that the proposed algorithm can be applied within the entire line and can accurately locate faults in different fault types, fault resistances, and fault distances.