• 한국기계가공학회지
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• 제15권1호
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• pp.26-33
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• 2016

In this study, a new method to develop a fixed diamond wire for silicon wafer machining by the multi-wire cutting method was developed. The new twist diamond wire has improved performance with high breaking strength and chip flutes structure. According to these characteristics, the new twist diamond wire can be used in the higher speed multi-wire cutting process with a long lifetime. Except the design of the new structure, the twist diamond wire is coating by electroless-electroplating process. It is good for reducing breakage and the falling-off of diamond grains. Based on the silicon material removal mechanism and performance of the wire-cutting machine, the optimal processing condition of the new twist diamond wire has been derived via mathematical analysis. At last, through the tensile testing and the machining experiments, the performance of the twist diamond wire has been obtained to achieve the development goals and exceed the single diamond wire.

• 패션비즈니스
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• 제11권5호
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• pp.51-63
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• 2007

Chitosan, a natural cationic macromolecular material, has been known for its moisturizing and healing effect due to the coating action based on strong ionic bonding when the chitosan is treated on hair strands. In this study, the acidic aqueous chitosan solution was prepared to treat healthy hair, and damaged hair due to bleaching, relatively thin hair and thick hair specimens. The chitosan treatment effect was reviewed by comparing spectrophotometric and mechanical characteristics of the chitosan treated and untreated specimens. Electrostatic voltage was somewhat reduced after the chitosan treatment. Smoothly coated surface was observed, in the SEM images, especially for damaged hair specimens. The values of breaking strength, which is one of the indicators of the internal characteristics of hair, was high in the case of chitosan treated samples. The values of elongation was also high in the case of chitosan treated samples, which proves the chitosan treatment effect. The friction force, one of the indicators of surface characteristics, was reduced for the case of chitosan treated samples.

• 패션비즈니스
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• 제11권5호
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• pp.79-89
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• 2007

The effect of chitosan treatment on the dyeing and dye fastness, and mechanical properties of hair was investigated in this study when the carotinoid dyestuffs extracted from African Marigold(Tagetes erecta L.) were applied to the hair. The sequences of the chitosan treatment were changed in dyeing and mordanting procedures, i.e., pre-treatment, mid-treatment, and post-treatment. While the effect of chitosan application on the color shade change was not significant, the pre-treatment of the chitosan increased the dye uptake. Discoloration and fading was observed in the lightfastness test when chitosan was mid-treated. Alkali perspiration and acid perspiration fastness test results showed that chitosan post-treatment gave lower tendency. Washing fastness results showed that chitosan post-treatment and mid-treatment gave lower values, which indicates that chitosan deters the direct formation of insoluble complex among fiber-dyestuff-mordant. In the mechanical characteristics results, however, initial modulus and breaking strength increased significantly in the post-treatment and pre-treatment of chitosan.

• Journal of the Korean Wood Science and Technology
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• 제34권5호
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• pp.88-97
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• 2006

Wood flour (WF)-recycled polypropylene (RPP) composites composed of 50% WF of Eucalyptus deglupta Blume species, 50% RPP, various contents of maleic anhydride (MAH) modifier (0; 1; 2; 5; 5; 7.5; and lo%), and 15% dicumyl peroxide (DCP) initiator (based on MAH weight) were subjected to weather for 1 year and subterranean termite (Coptotermes cuwignathus HOLMGREN) and dry wood termite (Cryptotermes cynocephalus LIGHT) for 3 and 4 weeks, respectively. WF-RPP composites with 2.5% MA modifier had tensile strength, breaking elongation and Young's modulus about 2.2, 2.3, and 1.2 times, respectively higher compared to MAH-free composites. The WF-RPP composites with or without MAH modifier had 5.5 times higher resistance to weather compared to RPP film alone. The color of the WF-RPP composites with or without MAH modifier became lighter after exposures to the weather. The WF-RPP composites with or without MAH modifier are resistant to subterranean termite Coptotermes curvignathus HOLMGREN and dry wood termite Cryptotermecs cynocephalus LIGHT under the experimental condition adopted.

• 한국염색가공학회지
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• 제24권1호
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• pp.91-96
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• 2012

The physical properties of recycled polyester yarns according to recycling methods were investigated. Virgin polyester draw texturized yarn(DTY), material-recycled(MR) polyester DTY and chemical-recycled(CR) polyester DTY were prepared. Surface morphology, thermal property, micro-structure and mechanical property of recycled polyester yarns were estimated. SEM-EDS analysis showed that the CR PET yarn had better crimp and more stable structure than MR PET yarn. Tm of the MR PET yarn was higher than that of the CR PET yarn. The intensity of the crystallization peak of the CR PET yarn was a little higher than that of the MR PET yarn. Tensile strength of the MR PET yarn was slightly higher than that of the CR PET yarn. Breaking elongation of the CR PET yarn was slightly higher than that of the MR PET yarn.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.165-166
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• 2014

The Composite waterproofing began to rise gradually 2000s in domestic. However, the sheet-membrane composite waterproofing method also acts as an abutment vulnerability that was a problem in a single method, and had the problem of damage to the formation of leakage paths. The existing non-overlap method, through vigorous research abutting sheet shall or could be developed to improve the seal performance of this method with the I-type joint coating material. Nevertheless, it has an integral top coat paint membrane and a sheet abutment limitation, damage to the upper membrane is damaged junction coating membranes has been generated. In this study, a method that has a layer of insulation on the joint bond breaker concept development, and to determine the physical properties with insulated joints to determine the breaking off of the upper joint is damaged coating membrane and tensile performance.

• 펄프종이기술
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• 제38권5호
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• pp.9-15
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• 2006

Wet compaction test (WCT) is a fiber evaluation method where wet fibers are compressed at one side of a cylinder and water drains out from the other side. The consistency of the fiber furnishes and their pressures are recorded during the test. In the previous study we found that WCT results always gave better coefficients of determination in fiber furnish drainage, and paper properties (density, tensile, tear, and burst strength) than those of WRV (water retention value). Fiber freeness and fiber length correlated well with drainage and tear strength of the furnishes, respectively; however, their correlations were very much improved by combining the WCT results. In this study, we used the WCT test for fractionated fiber furnishes to see whether improvement of the WCT is possible. We found that strength properties such as breaking length and burst index were correlated better with the fractionated long fiber furnishes. Drainage was greatly affected by the presence of short fiber furnishes. We used bleached chemical pulps (SwBKP, HwBKP), recycled pulp (OCC), and mechanical pulp (BCTMP) as fiber furnishes in this study. Fiber fractionation can be performed on-line in these days by using multifractor and WCT can be used as an on-line test in papermachine in the future.

• Design & Manufacturing
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• 제15권3호
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• pp.13-18
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• 2021

In plate forming technology, cylindrical drawing process is widely used in industry due to technological development. In this study, we used stainless steel 3042B and stainless steel 304J1, which are the most commonly used materials in the production of cold and hot water tanks for water purifiers, among cylindrical drawing products. Under the same conditions, the thickness of the sidewall of the product formed by drawn experiment was studied. As a result of the experiment, the bottom thickness of stainless steel 304J1 was considered to be thick. It is judged that the defect rate can be reduced by changing the breaking phenomenon of the floor surface of the cold and hot water bottles to the material of stainless steel 304j1. Stainless steel 304 2B material shows a sharp change in thickness from punch corner R to sidewall position, while stainless steel 304J1 material showed a uniform change from punch corner R to sidewall position. Stainless steel 304J1 material is considered to improve the clamping of the product in the process of extracting the product after hand drawing. The appearance of stainless steel 3042B products is considered to produce more wrinkles in the flange, which exerts greater tensile force on the sidewall during molding, resulting in uneven sidewall thickness.

• 대한금속재료학회지
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• 제46권1호
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• pp.1-5
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• 2008

This study has been investigated the deformation behavior of a hot-extruded Mg-Zn-RE (RE: rare earth elements) alloy containing $Mg_{12}$(RE) particles at the elevated temperatures. The particles are intrinsically produced by breaking the eutectic structure of the alloy during the hot-extrusion process. The grain size of the extruded Mg-Zn-RE alloy developed via dynamic recrystallization is around $10{\mu}m$. Under the heat treatment at 200o C up to 48 hr, no change has been observed on the microstructure and mechanical properties due to the pinning effect of the thermally stable particles. Under the tensile test condition in the initial strain-rate range of $1\times10^{-3}s^{-1}$ and the temperature range up to $200^{\circ}C$, the alloy shows yield strength of 270 MPa and elongation to failure around 9% at room temperature and yield strength of 135 MPa at $200^{\circ}C$. Furthermore, although the alloy contains large amount of the second phase particles around 15%, it shows excellent hot-workability possibly due to the presence of the thermally stable interface between the particles and the matrix.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.92-92
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• 2014

Recently, many state-of-art spectroscopy techniques are used to unravel the mysteries of condensed matters. And numerous heterostructures have provided a new avenue to search for new emergent phenomena. Especially, near the interface, various forms of symmetry-breaking can appear, which induces many novel phenomena. Although these intriguing phenomena can be emerged at the interface, by using conventional measurement techniques, the experimental investigations have been limited due to the buried nature of interface. One of the ways to overcome this limitation is in situ investigation of the layer-by-layer evolution of the electronic structure with increasing of the thickness. Namely, with very thin layer, we can measure the electronic structure strongly affected by the interface effect, but with thick layer, the bulk property becomes strong. Angle-resolved photoemission spectroscopy (ARPES) is powerful tool to directly obtain electronic structure, and it is very surface sensitive. Thus, the layer-by-layer evolution of the electronic structure in oxide heterostructure can be investigated by using in situ ARPES. LaNiO3 (LNO) heterostructures have recently attracted much attention due to theoretical predictions for many intriguing quantum phenomena. The theories suggest that, by tuning external parameters such as misfit strain and dimensionality in LNO heterostructure, the latent orders, which is absent in bulk, including charge disproportionation, spin-density-wave order and Mott insulator, could be emerged in LNO heterostructure. Here, we performed in situ ARPES studies on LNO films with varying the misfit strain and thickness. (1) By using LaAlO3 (-1.3%), NdGaO3 (+0.3%), and SrTiO3 (+1.7%) substrates, we could obtain LNO films under compressive strain, nearly strain-free, and tensile strain, respectively. As strain state changes from compressive to tensile, the Ni eg bands are rearranged and cross the Fermi level, which induces a change of Fermi surface (FS) topology. Additionally, two different FS superstructures are observed depending on strain states, which are attributed to signatures of latent charge and spin orderings in LNO films. (2) We also deposited LNO ultrathin films under tensile strain with thickness between 1 and 10 unit-cells. We found that the Fermi surface nesting effect becomes strong in two-dimensions and significantly enhances spin-density-wave order. The further details are discussed more in presentation. This work was collaborated with Hyang Keun Yoo, Seung Ill Hyun, Eli Rotenberg, Ji Hoon Shim, Young Jun Chang and Hyeong-Do Kim.