• 한국동물위생학회지
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• 제33권2호
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• pp.199-206
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• 2010

To evaluate the hypoglycemic effect of nano powder propolis, streptozotocin (STZ) induced diabetic rats were divided into 2 groups : diabetic control group and nano powder propolis (0.9ml) group. Then the rats were fed with nano-powder-propolis for 4 weeks. After 4 weeks, oral glucose tolerance test (oral GTT) was performed and blood sugar levels after 16 hours fasting, body weights, and blood lipid levels were measured. Finally, pancreas were collected and examined by histopathology and immunohistochemistry. In conclusion, the nano-powder-propolis was effective in the treatment of diabetes due to the reduction of blood sugar level and the regeneration of damaged ${\beta}$-cells observed in streptozotocin-induced diabetic rats.

• Applied Science and Convergence Technology
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• 제23권6호
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• pp.317-327
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• 2014

In order to develop nano-devices with much lower power consumption for beyond-CMOS applications, the fundamental understanding and precise control of the electronic properties of ultrathin transition metal oxide (TMO) films are strongly required. The metal-insulator transition (MIT) is not only an important issue in solid state physics, but also a useful phenomenon for device applications like switching or memory devices. For potential use in such application, the electronic structures of MIT, observed for TMO nano-structures, have been investigated using a synchrotron radiation angle-resolved photoelectron spectroscopy system combined with a laser molecular beam epitaxy chamber and a scanning photoelectron microscopy system with 70 nm spatial resolution. In this review article, electronic structures revealed by soft X-ray nano-spectroscopy are presented for i) polarity-dependent MIT and thickness-dependent MIT of TMO ultrathin films of $LaAlO_3/SrTiO_3$ and $SrVO_3/SrTiO_3$, respectively, and ii) electric field-induced MIT of TMO nano-structures showing resistance switching behaviors due to interfacial redox reactions and/or filamentary path formation. These electronic structures have been successfully correlated with the electrical properties of nano-structured films and nano-devices.

• 소성∙가공
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• 제17권5호
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• pp.337-342
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• 2008

The injection molding process has high accuracy and good reproducibility that are essential for mass production at low cost. Conventional molding processes typically use the water-based mold heating and air cooling methods. However, in the nano injection molding processes, this semi-active mold temperature control results in the several defects such as air-flow mark, non-fill, sticking and tearing, etc. In order to actively control temperature of the molds and effectively improve the quality of the molded products, the novel nano injection molding system, which uses active heating and cooling method, has been introduced. By using the Peltier devices, the temperature of locally adiabatic molds can be controlled dramatically and the quality of the molded patterns can be improved.

• 한국분무공학회지
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• 제16권3호
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• pp.134-139
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• 2011

Recent research has focused on engine combustion technology as well as application of after-treatment in order to comply with emission regulation. However, it is much more efficient way to control emissions from engine itself and furthermore research on engine control will provide the direction of after-treatment technology in future. Furthermore, emission standard regulation for passenger diesel vehicles has been stringent compared to others and nano-particles will be included in EURO6 regulation in Europe and similar emission standard will be introduced in Korea. A 3.0 liter high speed diesel engine equipped with by CRDI system of 160MPa injection pressure, and an intake/exhaust system of V type 6 cylinder turbo-intercooler was applied. The injection duration and injection quantity, pilot injection types which are related to CRDI and air/fuel ratio control applied by EVGT were changed simultaneously. Standard experiment procedure constituted dilution apparatus and CPC system to collect nano-particles and these test results were compared with regulated materials of CO, HC, NOx and investigated their relations and characteristics of nano-particles.

• International Journal of Aeronautical and Space Sciences
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• 제12권2호
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• pp.179-189
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• 2011

In this paper, robust adaptive control design problem is addressed for a class of parametrically uncertain aeroelastic systems. A full-state robust adaptive controller was designed to suppress aeroelastic vibrations of a nonlinear wing section. The design used leading and trailing edge control actuations. The full state feedback (FSFB) control yielded a global uniformly ultimately bounded result for two-axis vibration suppression. The pitching and plunging displacements were measurable; however, the pitching and plunging rates were not measurable. Thus, a high gain observer was used to modify the FSFB control design to become an output feedback (OFB) design while the stability analysis for the OFB control law was presented. Simulation results demonstrate the efficacy of the multi-input multi-output control toward suppressing aeroelastic vibrations and limit cycle oscillations occurring in pre- and post-flutter velocity regimes.

• Advances in nano research
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• 제4권3호
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• pp.181-195
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• 2016

Addition of nano-$SiO_2$ (NS) to geopolymer composites has been studied through measurement of compressive strengths, FTIR and XRD analysis. Alumino-silicate materials are coarse aggregate included waste concrete and demolished walls with its cementing binder, cement kiln dust (CKD) used and can possess a pronouncing activation for the geopolymer reaction resulting from the high alkali contents within. Materials prepared at water/binder ratios in a range of 0.30: 0.40 under curing of $40^{\circ}C$ and 100% Relative Humidity (R.H.), while the used activator is sodium hydroxide in the ratio of 2 wt. %. First, CKD is added in the ratio from 10 up to 50 wt., %, and the demolished walls was varied depending on the used CKD content, while using constant ratio of waste concrete (40 wt., %). Second step, depending on the optimum CKD ratio resulted from the first one (40 wt. %), so the control geopolymer mix composed of cement kiln dust, demolished walls and waste concrete in the ratio (40:20:40, wt %). Nano-silica partially replaced waste concrete by 1 up to 8%. Results indicated that, compressive strengths of geopolymer mixes incorporating nano-silica were obviously higher than those control one, especially at early ages and specially with 3%NS.

• 한국군사과학기술학회지
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• 제25권3호
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• pp.251-258
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• 2022

Infrared stealth technology used in aircraft is applied to reduce the infrared signal by controlling surface temperature and emissivity using internal heat sink, low emissivity material or metamaterial. However, there is one part of the aircraft where the use of this technology is limited, and that is the radome. Especially, radome should have transmittance for the specific radio frequency, therefore, common stealth technology such as emissivity control surfaces cannot be applied to radome surface. In this study, we developed metal nano-coating for infrared stealth which is applicable to radome surface. We designed slot-type pattern for frequency selective transmission in X-band, and also controlled thickness of metal nano-coating for long wavelength infrared emissivity control. As a result, our infrared stealth surface for radome has 93.2 % transmittance in X-band and various infrared emissivities from 0.17 to 0.57 according to nano-coatings thickness. Also, we analyzed infrared signature of radome through numerical simulation, and finally reduced contrast radiant intensity by 97.57 % compared to polyurethane surface.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.101-103
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• 2007

In this paper. we design a robust optimal controller for ultra-precision positioning system. Generally, it is hard to control the nanometric scale positioning system because of the parameter uncertainties and external disturbances. To solve this problem. we suggest a control algorithm based on the modified sliding-mode control and the LQ control in an augmented system. The augmented system is composed of additional state variables: state estimates and control input in the nominal system. Through comparison with LQ optimal control, it is verified that the proposed control algorithm is more robust to the unexpected parameter variations and external noises.

• 한국정밀공학회지
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• 제28권3호
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• pp.292-300
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• 2011

Control systems in machinery equipment provide correction signals to motion units in order to reduce or cancel out the mismatches between sensor feedback signals and command or desired values. In this paper, we introduce a simulator for control characteristics of machinery equipment. The purpose of the simulator development is to provide mechanical system designers with the ability to estimate how much dynamic performance can be achieved from their design parameters and selected devices at the designing phase. The simulator has a database for commercial parts, so that the designers can choose appropriate components for servo controllers, motors, motor drives, and guide ways, etc. and then tune governing parameters such as controller gains and friction coefficients. The simulator simulates the closed-loop control system which is built and parameter-tuned by the designer and shows dynamic responses of the control system. The simulator treats the moving table as a 6 degrees-of-freedom rigid body and considers the motion guide blocks stiffness, damping and their locations as well as sensor locations. The simulator has been under development for one and a half years and has a few years to go before the public release. The primary achievements and features will be presented in this paper.

• 식물병연구
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• 제15권2호
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• pp.130-133
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• 2009

Nano-silver 용액의 식물병원성 세균에 대한 항균 활성 검정을 하기 위해 Clavibacter michiganensis subsp. michiganensis를 포함한 10가지 균주를 대상으로 실험을 수행 하였다. Nano-silver용액은 바이오 (주)플러스에서 제공된 WA-CV-WA13B, WA-AT-WB13R과 WA-PR-WB13R용액을 사용하였으며, 10 ppm, 25 ppm, 50 ppm, 100 ppm 농도로 nano-silver 용액을 배지에 첨가하여 nano-silver 배지를 제조한 후 실험대상 세균 균주를 72 h 배양 후 생장억제 정도를 관찰하기 위하여 세균의 colony 수를 세었다. 실험 결과, WA-CV-WA13B 용액의 경우 C-1에 대하여 10 ppm에서도 높은 생장 억제 효과를 나타냈고, P-6, X-1, 그리고 X-2에 대해서도 생장억제 효과를 나타냈고, WA-AT-WB13R용액의 경우 10 ppm의 농도에서 P-6에 대하여 살균효과가 나타났다. 10 ppm의 농도에서는 C-1, X-1, 그리고 X-2에 대해서 약간의 생장억제 효과가 관찰 되었다. WA-PR-WB13R용액의 경우 10 ppm 혹은 그이상의 농도가 P-5, P-6, 그리고 X-2 균주에 대하여 살균효과를 나타내었다. 실험에 사용된 3가지 nano-silver 용액 모두 25 ppm 이상에서 모든 실험대상 식물병원성 세균에 대하여 살균효과를 나타내었으며, 이러한 결과는 nano-silver 용액을 식물병원성 세균의 방제제로 활용할 수 있는 가능성을 보여주는 결과라고 판된다.