• Journal of Convergence for Information Technology
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• v.7 no.1
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• pp.67-73
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• 2017

Paper sludge ash, blast furnace slag, fine powder quicklime, anhydrous gypsum, and fly ash as the main ingredients were prepared to suit the salty soils of marine soils. The solidification component is a kind of recycled ceramic, and CaO plays an important role in solidification. The neutralization time after solidification was about 2 weeks, and the compressive strength was about 12N/mm2 in the mortar test after one week incubation with standard yarn. This is about 14 times stronger than the solidifying agent used in the metropolitan area. As a result of applying plate load test to saltous marine soils, we obtained the yield load that can pass the large scale even after 5 days. In the uniaxial compressive strength test, shear strength of about 300 kPa was obtained after 5 days. It will be useful for supplementing the soft ground in the area where marine reclamation is much like the Incheon area.

• Korean Institute of Interior Design Journal
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• v.18 no.5
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• pp.137-146
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• 2009

The purpose of this study is to analyze the planning concept and spatial characteristics of the multi-housing units in prize-wining works of design competition since 2007. Literature review and content analysis were used for this study and 199units over $59m^2$ were analyzed to review the planning concept, spatial composition and layout. The results of this study were as follows; 1)The planning concept of these units were divided into three aspects; that is, eco-friendly, rational and sustainable unit plan by means of functional, environmental-friendly and future-oriented aspects. 2)Most unit plans had 3LDK+2bath and 4Bay types including family room as a public space. This results shows that family-room and bathroom has recently become more important than number of rooms in multi-housing units planning. 2)In terms of the spatial composition of LDK and Master Bed room, LDK area become large, open type and master-zone were showed 'bed room+dress and powder room+bath' type. 3)The entrance has a intermediated space as a balcony or a former space and the privacy of LDK space was protected from the entrance. This study has a significant moaning on grasping current trend in Korean multi-housing and to provide Information for future direction on housing-unit design.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.1
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• pp.64-70
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• 2018

In this study, the kg-class Ni-Al alloy fabrication process at low temperature was developed from the physical mixture of Ni and Al powders. The AlCl3 as an activator was used to reduce the temperature of alloy synthesis below the melting temperature of Ni and Al elements (<$500^{\circ}C$). Mixed phase of Ni3Al intermetallic and Ni-Al solid-solution were identified in the XRD pattern analysis. Furthermore, from the analysis of SEM and particle size analyzer, we found that the particle size of synthesized alloy powders was not changed compared to the initial size of Ni particle after the formation of alloy powder at $500^{\circ}C$. In the creep test, the anode (which was fabricated by the prepared Ni-Al alloy powders in this study) displayed the enhanced creep resistance compared to the conventional anode.

• Electronics and Telecommunications Trends
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• v.35 no.4
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• pp.1-10
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• 2020

Since the 1960s, semiconductor packaging technology has developed into electrical joining techniques using lead frames or C4 bumps using tin-lead solder compositions based on traditional reflow processes. To meet the demands of a highly integrated semiconductor device, high reliability, high productivity, and an eco-friendly simplified process, packaging technology was required to use new materials and processes such as lead-free solder, epoxy-based non cleaning interconnection material, and laser based high-speed processes. For next generation semiconductor packaging, the study status of two epoxy-based interconnection materials such as fluxing and hybrid underfills along with a laser-assisted bonding process were introduced for fine pitch semiconductor applications. The fluxing underfill is a solvent-free and non-washing epoxy-based material, which combines the underfill role and fluxing function of the Surface Mounting Technology (SMT) process. The hybrid underfill is a mixture of the above fluxing underfill and lead-free solder powder. For low-heat-resistant substrate applications such as polyethylene terephthalate (PET) and high productivity, laser-assisted bonding technology is introduced with two epoxy-based underfill materials. Fluxing and hybrid underfills as next-generation semiconductor packaging materials along with laser-assisted bonding as a new process are expected to play an active role in next-generation large displays and Augmented Reality (AR) and Virtual Reality (VR) markets.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.611-615
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• 2013

Vanadium oxide ($VO_2$) and tungsten-doped vanadium oxide (W-$VO_2$) powder, well known as thermochromic materials, were prepared from vanadium pentoxide ($V_2O_5$) and oxalic acid dihydrate by hydrothermal and calcination process. The crystal structure and thermochromic property of samples were analyzed using FE-SEM, XRD, XPS, DSC, and UV-Vis-NIR spectroscopy. With increasing the doping amount of W, the phase transition temperature of W-$VO_2$ sample decreased from $70^{\circ}C$ to $42^{\circ}C$. When heating W-$VO_2$ sample above the phase transition temperature, the UV-Vis-NIR spectrum was not changed in the visible range and shifted towards a low transparency in the full name (NIR) region.

• Composites Research
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• v.33 no.4
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• pp.213-219
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• 2020

Recently, global facing environmental issues have been raised caused by plastic waste. Hence, increasing the demand for interest in environmentally friendly materials. In this row, research on engineering composite materials also replacing the synthetic reinforcement by introducing natural fibers. However, focus on the strength and interfacial adhesion between matrix and reinforcement is very essential in natural fiber composite, which is insufficient in the literature. There are number of approaches for improving the mechanical strength of the composites, one of the common methods is to reinforce additive nanoparticles. The present investigation, bio-additives were synthesized utilizing bio-waste, cheap, bio-degradable sea-weed powder that could replace expensive nanomaterials and reinforced into the CFRP composite through Hand lay-up followed by a vacuum process. Mechanical properties were evaluated and analyzed through microanalysis. The results concluded that synthesized additives are effective for improving mechanical properties such as tensile, flexural, impact, and shear strength. Overall, the results confirmed that the fabricated composites have potential applications in the field of engineering applications.

• Clean Technology
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• v.22 no.4
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• pp.250-257
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• 2016

As an attempt to replacing petroleum-based chemicals with bio-based ones, synthesis of furfural from biomass-derived xylose attracts much attention in recent days. Conventionally, furfural from xylose has been produced via the utilization of highly corrosive, toxic, and environmentally unfriendly mineral acids such as sulfuric acid or hydrochloric acid. In this study, microwave-assisted biphasic reaction process in the presence of novel bio-based heterogeneous acid catalysts was developed for the eco-benign and effective synthesis of furfural from xylose. The microwave was irradiated for reaction acceleration and a biphasic system consisting of $H_2O$ : MIBK (1 : 2) was designed for continuous extraction of furfural into the organic phase in order to reduce the undesired side products formed by decomposition/condensation/oligomerization in the acidic aqueous phase. Moreover, sulfonated amorphous carbonaceous materials were prepared from wood powder, the most abundant lignocellulosic biomass. The prepared catalysts were characterized by FT-IR, XPS, BET, elemental analysis and they were used as bio-based heterogeneous acid catalysts for the dehydration of xylose into furfural more effectively. For further optimization, the effect of temperature, reaction time, water/organic solvent ratio, and substrate/catalyst ratio on the xylose conversion and furfural yield were investigated and 100% conversion of xylose and 74% yield of furfural was achieved within 5 h at $180^{\circ}C$. The bio-based heterogeneous acid catalysts could be used three times without any significant loss of activity. This greener protocol provides highly selective conversion of xylose to furfural as well as facile isolation of product and bio-based heterogeneous acid catalysts can alternate the environmentally-burdened mineral acids.

• KIEAE Journal
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• v.10 no.5
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• pp.115-121
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• 2010

Lime was the solidifier mostly used at the fields of construction and civil works in the past. however, the development of Portland cement remarkably reduced the use of it. Recently as the concernment on circumstances gets higher, lime wined attention again as an eco-friendly material and was used at earth-using construction. This study examined the physical and chemical capacity of lime complexes with lime capacity improved, and performed fundamental study on the way to concretize by mixing it with earth. As a result, lime complex pressure strength was lower than cement pressure strength but it showed the possibility that its strength was improved by W/B control. The measurement of XRD after paste formation confirmed a compound generated by the reaction of Ca2+ion and Si, Al, and Fe from pozzolan reaction. A earth wall experiment by using lime complexes and earth showed that the higher, WB or the lower the quantity of unit combined materials, the lower the pressure strength was. The maximum pressure strength was maximum 11MPa when the quantity of unit combined materials was 450. It is because the composed earth particles had a high content of micro powder less than silt, so a lot of combination are demanded to secure fluidity. As a result of peptization experiment, after hardening, the material was not dissolved, which informed of the possibility of use as an outer subsidiary material. If the material is hardened by mold formation method, natural hardening crack appears. Cast expresses smart surface quality and enables to design for multiple purpose. The result shows the possibility of construction of low-story structures by using earth wall made of lime complexes and earth.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.385-390
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• 2015

In order to develop an eco-friendly biofertilizer, a plant growth promoting rhizobacterium (PGPR), Bacillus sp., SH1RP8 was investigated. SH1RP8 was lyophilized via freeze-drying along with other protective agents that protect cells from lysis. The freezedried powder of Bacillus sp. SH1RP8, containing 5% skim milk (w/v), exhibited the highest survival rate of 30.6% among all the protective agents (skim milk, glucose, and peptone). The lyoprotective effect of the skim milk, mixture including 5% skim milk, and substrates on the survival of the test strain was examined. Control group was added only skim milk and test groups were added skim milk and other substrates. As a result, the group supplemented with both glycerol and 5% skim milk showed the protective effect much higher by 214.29% than the control group. Freeze-dried Bacillus sp. SH1RP8 could be a good candidate as a potential biofertilizer due to its effective PGPR activity.

• Korean Journal of Metals and Materials
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• v.50 no.3
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• pp.201-205
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• 2012

The effects of various manganese precursors for the low-temperature selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyses. $MnO_x/TiO_2$ catalysts were prepared from three different precursors, manganese nitrate, manganese acetate(II), and manganese acetate(III), by the sol-gel method. The manganese acetate(III)-$MnO_x/TiO_2$ catalyst tended to suppress the phase transition from the anatase structure to the rutile or the brookite after calcination at $500^{\circ}C$ for 2 h. It also had a high specific surface area, which was caused by a smaller particle size and more uniform distribution than the others. The change of catalytic acid sites was confirmed by Raman and FT-IR spectroscopy and the manganese acetate(III)-$MnO_x/TiO_2$ had the strongest Lewis acid sites among them. The highest de-NOx efficiency and structural stability were achieved by using the manganese cetate(III) as a precursor, because of its high specific surface area, a large amount of anatase $TiO_2$, and the strong catalytic acidity.