• Journal of the Korean Institute of Gas
• /
• v.14 no.3
• /
• pp.41-45
• /
• 2010

The physical properties of DME(Dimethyl Ether) are very similar to LPG and well-mixed. As cetane number of DME is similar to diesel fuel that can replace diesel fuel and alternative energy. DME is a clean energy source that can be manufactured from various raw materials such as natural gas, CBM(Coal Bed Methane) and biomass. DME has no carbon-carbon bond in its molecular structure and its combustion essentially generates no soot as well as no SOx. The development of DME process in KOGAS have 4 section. First, syngas section can be manufactured various syngas ratio. This completes the tri-reforming process for the synthesis gas ratio of approximately 4.0 to 1.0 range can be adjusted. Second, $CO_2$ is removed from the $CO_2$ removal section of about 92~99%, so the maximum concentration of $CO_2$ entering the DME synthesis reactor should not exceed 8%. Third, in the DME synthesis section, if the temperature of DME reactor increases, the activity of DME catalyst increased. but for the long-term activity is desirable to maintain the proper temperature. Finally, the purity of DME in the DME purification section is over 99.6%.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.36C no.10
• /
• pp.8-16
• /
• 1999

This paper presents a new simulation-based analog cell synthesis approach with improved simulation efficiency For the hierarchical synthesis of analog cells we developed the sub-circuit optimizers such as current mirror and differential input stage. Each sub-circuit optimizer can be used for synthesis of analog cells such as OTA(operational transconductance amplifier), 2-stage OP-AMP and comparator. To reduce the time spending of the simulation-based synthesis we propose 2-stage searching scheme and simulation data reusing scheme. With those schemes the synthesis time spending of OTA was reduced from 301.05sec to 56.52sec by 81.12%. Since our synthesis system doesn't need other additional physical parameters except SPICE parameters, and is independent of the process and its model level, the time spending to port to other process is minimized. We synthesized OTA and 2-stage OP-AMP respectively with our approach to show its usefulness.

• Applied Chemistry for Engineering
• /
• v.33 no.4
• /
• pp.402-407
• /
• 2022

Statistical design of experiments was used to optimize the MOF-5 synthesis process. A mixture design was employed to optimize precursor concentration. The optimal composition of three chemical materials, terephthalic acid, zinc acetate dihydrate, and N,N-dimethylformamide for MOF-5 synthesis was determined by extreme vertices design methods as follows; 1 mol : 2.7 mol : 40 mol. A multilevel factorial design was selected to screen the significance of synthesis reaction conditions such as temperature, time, and stirring speed. Statistical analysis results suggested excluding stirring speed from further investigation. Using a central composition design, the synthesis time and temperature were optimized. The quadratic model equation was derived from 13 synthesis experiments. The model predicted that MOF-5 synthesized at 119 ℃ for 10.4 h had the highest crystallinity.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.3
• /
• pp.555-562
• /
• 2008

In this paper we proposed a practical low-power design technique using clock-gating in RTL. An efficient low-power methodology is that a high-level designer analyzes a generic system and designs a controller for clock-gating. Also the desirable flow is to derive clock-gating in normal synthesis process by synthesis tool than to insert directly gate to clock line. If low-power is considered in coding process, clock is gated in coding process. If not considered, after analyzing entire operation. clock is Bated in periods of holding data. After analyzing operation for clock-gating, a controller was designed for it, and then a low-power circuit was generated by synthesis tool. From result, we identified that the consumed power of register decreased from 922mW to 543mW, that is the decrease rate is 42%. In case of synthesizing the test circuit using synthesizer of Power Theater, it decreased from 322mW to 208mW (36.5% decrease).

• Bulletin of the Korean Chemical Society
• /
• v.16 no.10
• /
• pp.1002-1003
• /
• 1995

• Archives of Pharmacal Research
• /
• v.23 no.6
• /
• pp.564-567
• /
• 2000

The use of amino acid derivatives as building blocks in peptide synthesis is increasingly being recognized as a potential route for the development of pharmaceutical agents. Side chain protection of polyfunctional amino acids such as Ser, Thr, Tyr is viewed as being particularly important. Although these derivatives are commercially listed, they are expensive and not widely available. We describe here a practical large-scale synthesis of t-butyl introduced D-serine, one of the building blocks of zoladex, a peptide drug.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.1692-1696
• /
• 2014

A practical and efficient one-pot synthesis of 1,3,5-trisubstituted pyrazoles from ${\alpha},{\beta}$-enones and arylhydrazine hydrochlorides has been developed. The pyrazoles were formed via a tandem formation of the corresponding pyrazolines and an acid-catalyzed aerobic oxidation process.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.451-456
• /
• 1989

New image coding system for facial images called 'Knowledge-based image coding' is described, in which input image is analyzed and output image is synthesized using analysis results. Analysis and synthesis method of facial expressions are presented. Synthesis rules are determined on the basis of facial muscles and are also used in analysis process to produce a faithful reconstruction of the original image. A number of examples are shown.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1303-1304
• /
• 2008

Nickel wire of 0.2mm diameter and 50mm in length was exploded in ethanol for Ni nanopower synthesis. The waveform of discharge current shows that the process can be divided by ohmic heating phase and plasma state. The Ni nanopowder classified after synthesis has 100nm of mean diameter.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.7
• /
• pp.2145-2148
• /
• 2012

A new thiourea based receptor (1) was synthesized and applied to fluoride ion recognition in acetonitrile solution. Receptor 1 displayed dual changes in absorption and fluorescence emission intensities selectively for fluoride ions. The interaction of 1 with fluoride undergoes a deprotonation process that is confirmed by $^1H$ NMR titration.