• KSBB Journal
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• 제26권4호
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• pp.283-292
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• 2011

Solid dispersion is one of well-established pharmaceutical techniques to improve the dissolution and consequent bioavailability of poorly water soluble drugs. It is defined as a dispersion of drug in an inert carrier matrix. Solid dispersions can be classified into three generations according to the carrier used in the system. First and second generations consist of crystalline and amorphous substances, respectively. Third generation carriers are surfactant, mixture of polymer and surfactants, and mixture of polymers. Solid dispersions can be generallyprepared by melting method and solvent method. While melting method requires high temperature to melt carrier and dissolve drug, solvent method utilizes solvent to dissolve the components. The improvement in dissolution through solid dispersions is attributed to reduction in drug particle size, improvement in wettability, and/or formation of amorphous state. The primary characteristics of solid dispersions, the presenceof drug in amorphous state, could be determined by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and fourier-transformed infrared spectroscopy (FTIR). In spite of the significant improvement in dissolution by solid dispersion technique, some drawbacks have limited the commercial application of solid dispersions. Thus, further studies should be conducted in a direction to improve the congeniality to commercialization.

• Corrosion Science and Technology
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• 제23권4호
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• pp.334-342
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• 2024

The need for efficient and sustainable energy storage solutions has emerged due to a rapidly increasing energy demand and growing concerns about environmental issues. Among various energy storage methods, lithium secondary batteries are widely used in a variety of electronic devices such as smartphones, laptops, electric vehicles, and large-scale power storage systems due to their high energy density, long lifespan, and cost competitiveness. Recently, all-solid-state batteries (ASSBs) have attracted great attention because they can reduce the risk of fire associated with liquid electrolytes. Additionally, using high-capacity alternative anodes and cathodes in ASSBs can enhance energy density. However, ASSBs that use solid electrolytes experience a degradation in their electrochemical performances due to resistance at solid-solid interfaces. These interfaces can also result in poor physical contact and the presence of products formed from chemical and electrochemical reactions. Solving this interface problem is a critical issue for the commercialization of ASSBs. This review summarizes interfacial reactions between the cathode and solid electrolyte, along with research aimed at improving these interactions. Future development directions in this field are also discussed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.98-105
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• 1997

The behaviour of alloys in the semi-solid state strongly depends on the imposed stress state and on the morphology of the phase which can very from dendritic to globular. The estimation of behaviour characteristic in the compression simulation with seim-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for compression process is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process considering soldification phenomena is performed to the isothermal conditions of two dimensional problems. To analysis of compression process by using semi-solid materials, a new stress-strain relationship is described, and compression analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for compression force and ram displacement will be compared to experimental data.

• 반도체디스플레이기술학회지
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• 제22권1호
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• pp.28-32
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• 2023

Recently, the use of stable lithium nanostructures as substrates and electrodes for secondary batteries can be a fundamental alternative to the development of next-generation system semiconductor devices. However, lithium structures pose safety concerns by severely limiting battery life due to the growth of Li dendrites during rapid charge/discharge cycles. Also, enabling long cyclability of high-voltage oxide cathodes is a persistent challenge for all-solid-state batteries, largely because of their poor interfacial stabilities against oxide solid electrolytes. For the development of next-generation system semiconductor devices, solid electrolyte nanostructures, which are used in high-density micro-energy storage devices and avoid the instability of liquid electrolytes, can be promising alternatives for next-generation batteries. Nevertheless, poor lithium ion conductivity and structural defects at room temperature have been pointed out as limitations. In this study, a low-dimensional Graphene Oxide (GO) structure was applied to demonstrate stable operation characteristics based on Li+ ion conductivity and excellent electrochemical performance. The low-dimensional structure of GO-based solid electrolytes can provide an important strategy for stable scalable solid-state power system semiconductor applications at room temperature. The device using uncoated bare NCA delivers a low capacity of 89 mA h g-1, while the cell using GO-coated NCA delivers a high capacity of 158 mA h g−1 and a low polarization. A full Li GO-based device was fabricated to demonstrate the practicality of the modified Li structure using the Li-GO heterointerface. This study promises that the lowdimensional structure of Li-GO can be an effective approach for the stabilization of solid-state power system semiconductor architectures.

• 보존과학회지
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• 제5권1호
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• pp.69-86
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• 1996

More than eighty thousands of wooden printing blocks of the Tripitaka Koreans are accommodated in the Changkyeonggak which consists of two open structured wooden buildings, Peoppojeon and Sudarajang. These blocks are virtually in pristine state even after three quarters of a millennium. The excellent preservation could be attributed to the careful preparation and meticulous finish of the blocks. But the meteorological environment or microclimate should be one of the key factors for the preservation. To keep the blocks intact as it is or at least do not accelerate the deterioration, we should study the blocks and its microclimatic environment supplied by the Changgyeonggak and the topology of the site. As a Part of this effort we designed a computerized meteorological data acquisition system, which can handle up to 4,096 sensors. A partial but operative installation of 16 temperature/humidity sensors was set up in the Peoppojeon. We hope to have a chance to install a full fledged system in the near future for the compilation of the fuller environmental data base.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.91-96
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• 2005

In this paper, describes the design and performance of a 1.5 kW solid-state pulsed power amplifier, operating over 2.7-2.9 GHz at a duty of 10% and with a pulse width of 100 us for radar application. The solid-state pulsed power amplifier configures a series of 8-stage cascaded power amplifier with different RF output power levels. Low loss Wilkinson combiners are used to combine output powers of six 300W high power solid state modules. Tests show peak output power of 1.61 kW, corresponding to PAE of 26.2% over 2.7-2.9 GHz with pulse width of 100 us and a PRF of 1 kHz.

• 분석과학
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• 제17권5호
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• pp.388-392
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• 2004

genomics의 정보해석이나 신경전달물질 또는 약의 전달체계에서 아주 중요한 역할을 담당하는 막단백질의 구조연구는 기존의 X-ray나 용액상 핵자기공명분광법으로 수행하기 어려우나 지방질 이분자층이나 여러분자층에서 움직이지 않게 정렬시킨 단백질시료를 이용하여 특이하게 고안된 home-built solid-state NMR probe를 이용하면 구조를 연구할 수 있다. 이 논문에서는 박테리오파지인 pf1의 growth, 분리, 정제 및 pf1에서의 coat protein의 분리, 정제과정과 최종적으로 분리 정제된 pf1의 coat protein의 인산지방질 이분자층에서의 구조를 고체상 핵자기공명 분광법을 이용하여 연구하고자 한다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권1호
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• pp.99-106
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• 2012

For CMOS technology of 65 nm and beyond, the gate leakage current can not be negligible anymore. In this paper, the impact of the gate leakage current in ring voltage-controlled oscillator (VCO) on phase-locked loop (PLL) is analyzed and modeled. A voltage -to-voltage (V-to-V) circuit is proposed to reduce the voltage ripple on $V_{ctrl}$ induced by the gate leakage current. The side effects induced by the V-to-V circuit are described and optimized either. The PLL design is based on a standard 65 nm CMOS technology with a 1.8 V power supply. Simulation results show that 97 % ripple voltage is smoothed at 216 MHz output frequency. The RMS and peak-to-peak jitter are 3 ps and 14.8 ps, respectively.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.823-826
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• 2013

A low-${\varepsilon}$ solid-state NMR(Nuclear Magnetic Resonance) probe was developed for the spectroscopic analysis of two-dimensional $^{15}N-^1H$ heteronuclear dipolar coupling in dilute membrane proteins oriented in hydrated and dielectrically lossy lipid environments. The system employed a 800 MHz narrow-bore magnet. A solenoid coil strip shield was used to reduce deleterious RF sample heating by minimizing the conservative electric fields generated by the double-tuned resonator at high magnetic fields. The probe's design, construction, and performance in solid-state NMR experiments at high magnetic fields are described here. Such high-resolution solid-state NMR spectroscopic analysis of static oriented samples in hydrated phospholipid bilayers or bicelles could aid the structural analysis of dilute biological membrane proteins.

• KSBB Journal
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• 제28권6호
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• pp.400-407
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• 2013

The growth characteristics and production of color pigments by Monascus strains were investigated during liquid culture, and production of monacolin K in red mold rice was carried out by solid state fermentation. Four different Monascus ruber strains were cultured in potato dextrose yeast extract broth (PDYB) media at $25^{\circ}C$ for 15 days. The high producing strain for red pigment was not corresponded to the strain for yellow pigment. Production of red pigment was high in the strain causing the fast pH change in culture broth. Production of monacolin K in red mold rice by solid state fermentation was influenced by a combination of wet cell weight and spore density in inoculum by liquid culture. Most strains showed the high production of monacolin K in red mold rice, when submerged fermentation was carried out for 5 days as inoculum for solid state fermentation. These results suggest that submerged fermentation period of inoculum have an effect on the production of monacolin K in red mold rice by solid state fermentation, and monacolin K in red mold rice could be increased by controlling the condition of submerged fermentation for inoculum.