• Applied Biological Chemistry
• /
• v.30 no.1
• /
• pp.65-70
• /
• 1987

In Girder to measure the pressure and weight decrease of drying sample during the vacuum drying process of food, sensing devices were designed and constructed with strain gauge. Microcomputer based vacuum drying system was made up of these devices interfaced to apple II microcomputer. The electrical output signal from vacuum sensor which constituted with Bourdon tube whereon strain gauge attached were digitalized and input to microcomputer through the MC 6821 interface I.C. chip. The relationship between read-out digital value (D) from microcomputer and readings of vacuum gauge (P, mmHg) was P=-146.136+3.620D'(r=0.9994) The pressure control of vacuum dryer was successfully conducted in the range of $400{\sim}600\;mmHg$ accuracy. The digitalized load cell output (D) could be correlated with the real weight (W, g) as W=-14,000+0.585D (r=0.9998) Drying curves of green red pepper under $64^{\circ}C$, $400{\sim}600\;mmHg$ was similar to those of red pepper and differently affected by the degree of vacuum pressure but was varied according to their shape (cut or whole). Moisture movement of green red pepper during the vacuum drying process was fitted to Page model. The empirical equations obtained were $M-M_e/M_o-M_e={\exp}\;(-0.0673{\theta}^{1.177})$ and $M-M_e/M_o-M_e={\exp}\;(-0.0655\;{\theta}^{1.477})$ for whole and cut green red pepper, respectively.

• Journal of the Microelectronics and Packaging Society
• /
• v.30 no.4
• /
• pp.86-90
• /
• 2023

The packaging of electronic devices performs a protective function to ensure that their durability and reliability are not affected by changes in the operating environment caused by external factors. Recent advances in materials have led to ongoing research into bonded packaging of heterogeneous materials such as polymers and inorganic materials in electronic devices. In this packaging process, it is important to have a binding that joins the materials and ensures the operating environment, which includes adhesion to the substrate, corrosion and oxidation resistance through moisture removal, and durability. In this study, the hygroscopicity of the coating layer by modifying the polymer surface based on PVA was evaluated by controlling and measuring the contact angle, and the adhesion was confirmed by applying water-based ink and testing according to ASTM_D3363. For the durability of the polymer surface, the IPL post-treatment process was used to improve the hardness and toughness against applied voltage, and the pencil hardness test and nanoindentation test were conducted. Through this, we analyzed and proposed solutions to ensure the reliability and durability of polymer devices in polymer microfabrication against environmental factors such as moisture, temperature fluctuations and adhesion, and surface abrasion.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2102-2104
• /
• 2004

In this study, sheathless electrospray from PDMS/glass microchips with conducting metal emitter tip is described. A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system has advantages of the CE separation and on-line electrospray detection of peptide solution. We have fabricated a new electrospray ionization(ESI) device composed of the metal emitter tip and CE separation channel monolithically in a glass microchip. The separation channel and metal emitter tip are fabricated using a glass wet etching and gold electro plating process, respectively. The fabricated micro electrospray chip was tested by spraying peptide sample for mass spectrometric analysis. Singlely-charged peak and doublely-charged peak of peptide were detected and further MS/MS fragmentation was performed in each peak. Direct comparisons with conventional glass or fused silica emitters showed very similar performance with respect to signal strength and stability.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.5
• /
• pp.69-74
• /
• 2010

In this paper, we proposed a compact arbitrary dual-band band-stop filter using CRLH transmission line. The proposed filter used CRLH transmission line as stub and it developed dual-band band-stop characteristics using non-linear phase response of CRLH transmission line. The size of proposed filter is compact. And it can control arbitrary dual stop band. In this paper, designed band-stop filter at GPS band and ISM band As result, the S(2,1) is about -30dB at GPS band and about -29dB at ISM band. The fabricated filter is very compact. Its dimension is 10mm*15mm.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.349-349
• /
• 2012

산화제를 이용 기상중합법을 통해 합성되는 고전도도 Poly (3,4-Ethylenedioxythiophene)(PEDOT) 박막은 OTFT, RFID tag, 또는 연성 디스플레이 같은 분야에 다양한 응용 가능성을 가지고 있으며 이로 인해 최근에 연구가 활발히 진행되고 있다. PEDOT박막의 전극소재로써 가능성은 박막의 중합 정도와 표면 형상에 크게 좌우된다. 특히, Si-웨이퍼 기판 위에 산화제의 균일한 도포 및 산화제 자체의 높은 산도 ($pH{\leq}2$)에 따른 부반응의 억제는 기상중합법을 이용한 PEDOT박막의 합성에 있어 매우 중요하다. PEDOT의 효율적인 중합과 균일한 성장을 위해 산화제에 DUDO 와 PEG-PPG-PEG를 첨가한 혼합 산화제 용액을 제조 기상중합 방법을 통해 PEDOT박막을 제작하였다. 그 결과 산화제만을 사용하여 제작된 박막에 비해 전도도가 최대 3,660 S/cm로 향상된 PEDOT 박막이 합성되었다. 이러한 결과는 PEG-PPG-PEG가 산화제 용액의 균일 도포를 향상시키고 Base Inhibitor로 작용하는 DUDO는 PEDOT 성장 시 중합속도를 조절하고 부반응을 최소화 하여 효율적인 공액 이중 결합의 생성을 촉진한데 주로 기인한다. 따라서 그로인해 조밀하며 마이크로 스케일의 기공이 최소화된 PEDOT박막의 합성이 가능하였다. PEDOT박막의 특성 평가에는 4-point probe, optical microscopy, Field Emission-Scanning Electron Microscope, 등이 사용되었으며 또한 전도도의 향상 원인을 분석하고자 ATR-IR Spectrophotometer를 이용하여 합성된 박막의 작용기를 분석하였다. 이러한 고전도도의 PEDOT 박막이 OTFT의 전극소재로 사용된다면 OTFT소자의 성능 향상에 크게 기여 할 것으로 기대된다.

• Journal of Advanced Navigation Technology
• /
• v.11 no.4
• /
• pp.408-414
• /
• 2007

Research advances in the areas of micro-sensor device and wireless network technology, has made it possible to develop energy efficient and low cost wireless sensor nodes. In this paper, the forward error control (FEC) scheme for lower power consumption and excellent BER(Bit Error Rate) performance during transmission propose in multi-hop wireless sensor network based on FSK modem. The FEC technique uses extra processing power related to encoding and decoding, it is need complex functions to be built into the sensor node. The probability of receiving a correct bit and codeword for relaying a frame over h nodes to the sink node is calculated as a function of channel parameter, number of hops, number of bits transmitted and the distance between the different nodes.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.7
• /
• pp.1071-1075
• /
• 2003

In this paper, we present a DNA manipulation device in the reaction chamber, which consists of a center electrode and circular outer electrodes of a reaction unit. The charged bio-molecules, DNA, are manipulated by the charge of the electrode in reaction unit. Controlling the induced dynamic electric field between the center electrode and the outer electrodes, concentration / repulsion / manipulation of bio-molecules are enabled at a periphery of electrode. Concentration of the fluorescent DNA at the center electrode is observed by applying ＋2V. Subsequently, applying －2V, the concentrated DNA is repelled rapidly from the center electrode, which makes dispersion completely in 0.5second. Furthermore, repeated applying ＋1V/－1V every 5 seconds at each outer electrode, we can circulate the DNA. We also investigate a micro-heater and sensor for DNA manipulation and reaction temperature. The coefficient of heat-resistance and heater temperature characteristic is 0.0043 and 100$^{\circ}C$/sec, respectively.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.12-17
• /
• 1991

In this paper, E-plane gap-coupled rectangular microstrip antennas with parasitic elements are analyzed. The mutual coupling between the radiating edges is represented as the voltage-dependent current source. The gap coupling between the patch and parasitic element is characterized with the REC(Radiating Edges-Coupling) model, and the conventional transmission line model is used to obtain the equivalent circuit of the antenna. The return loss of the rectangular microstrip antennas with short-and open-circuit parasitic elements are calculated and compared with the measured values. The theoretical values including the mutual coupling are more in agreement with the measured values than the calculated values without the mutual coupling.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.4 s.346
• /
• pp.44-51
• /
• 2006

In this paper, the resonance characteristics of zigzag wire dipole antennas are first analyzed by the method of moment(MOM) for shortening the space occupation length of straight wire dipole antenna Considering the shortening effect the integrated zigzag dipole antennas with the simplified microstrip feed are designed. Since the integration gives rise to discontinuities due to antenna line width with abrupt bend angles, the compensation by the chamfer is applied. Futhermore the integrated parasitic zigzag lines are properly attached to both sides of substrate for compensation of the effect of the dielectric substrate, hence improving the resonance characteristic. The design results at UHF and ISM band are verified with experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.4
• /
• pp.359-365
• /
• 2002

In this work, a new type of the active array antenna for IMT-2000 base stations by using dual-polarization diversity is proposed and developed. As an element of array antenna, a single micorstrip patch antenna of ${\pm}$ 45$^{\circ}$slanted is designed by obtaining the bandwidth of 1,885 ㎒ to 22,000 ㎒. The polarization isolation between two linearly polarized waves is less than 16 ㏈. The gain of element antenna is more than 7 ㏈i. finally, 2${\times}$8 dual-polarization active array antenna is developed with ElRP of 1,200 W and polarization isolation of 20 ㏈ by placing a low power amplifier at each antenna element.