• Journal of the Korean Society for Heat Treatment
• /
• v.29 no.1
• /
• pp.1-7
• /
• 2016

Titanium and its alloys can be usually joined with brazing method. And the alloys should be brazed at low temperature to keep their original microstructure. In this study, the mechanical strength and microstructure of the CP-Ti joint-brazed with $Zr_{54}Ti_{22}Ni_{16}Cu_8$ filler metal having melting temperature of $774{\sim}783^{\circ}C$ were investigated. The tensile strengths of the joint-brazed at $800^{\circ}C$ with $100^{\circ}C/min$ of cooling rate showed more than 400 MPa which was as high as base metal. The $Widmanst{\ddot{a}}tten$ structure consisting of Ti and $Ti_2Ni$ phase was observed in the joint area. However, the tensile strengths of the joint-brazed at $800^{\circ}C$ with $15^{\circ}C/min$ of cooling rate were decreased and the Ti, $(Ti,Zr)_2Ni$ and $Ti_2Ni$ phases were observed at the joint area. It is believed that the $(Ti,Zr)_2Ni$ laves phases could decrease the mechanical strength of the joint and the cooling rate should be controled to get high strength of the titanium joint.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.75-75
• /
• 2003

We report here the results on N-acetyl-N'-dimethylamide of proline (Ac-Pro-NM $e_2$) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level with the 6-31+G(d) basis set to investigate the conformational preference of polyproline depending on the cis/trans peptide bonds and down/up puckerings along the backbone torsion angle $\square$ in the gas phase, chloroform, and water. In the gas phase, Ac-Pro-NM $e_2$ has seven local minima of tFd, tFu, cFd, cFu, cAu, tAu, and cAd conformations. In particular, polyproline conformations tFd, tFu, cFd, and cFu are found to be more stable than $\square$-helical conformations cAu, tAu, and cAd. In contrast, Ac-Pro-NHMe has seven local minima of tCd, tCu, cBd, cAu, tAu, cFd, and cFu conformations. Conformations tCd and tCu are found to be most stable, which is ascribed to the intramolecular hydrogen bond between C=O of acetyl group and $N^{~}$ H of N'-methyl amide group. The stability of the cFd conformation (i.e., the polyproline I structure) in chloroform is somewhat increased, relative to that in water, although tFd and tFu conformations (i.e., the polyproline II structure) are dominate both in chloroform and water. The population of backbone conformations feasible in chloroform and water is consistent with the experiments. This work is supported by a Korea Research Foundation Grant (KRF-2002-041-C00129).

• Korean Journal of Materials Research
• /
• v.26 no.3
• /
• pp.154-159
• /
• 2016

A roll-bonding process was applied to fabricate an AA1050/AZ91/AA1050 laminate complex sheet. Two AA1050 and one AZ91 magnesium sheets of 2 mm thickness, 30 mm width and 200 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 2 mm in thickness by conventional rolling. The rolling was performed at 623K without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 15.9 m/min. The AA1050/AZ91/AA1050 laminate complex sheet fabricated by roll bonding was then annealed at 373~573K for 0.5h. The microstructure of the complex sheets was revealed by electron back scatter diffraction (EBSD) measurement; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the complex sheet was found to increase by 11 % and the tensile elongation decreased by 7%, compared to those values of the starting material. In addition, the hardness of the AZ91 Mg region was slightly higher than those of the AA1050 regions. Both AA1050 and AZ91 showed a typical deformation structure in which the grains were elongated in the rolling direction; however, the mis-orientation distribution of grain boundaries varied greatly between the two materials.

• Lingua Humanitatis
• /
• v.2 no.2
• /
• pp.85-107
• /
• 2002

The word play on h(e)art-hunting has become a virtual commonplace in criticism of Chaucer′s Book of the Duchess. Less widely discussed is the third meaning of ME herte, "hurt." The "hart"/ "heart" pun is, however, only implicit in the poem, while the rhyme of "heart" and "hurt" in lines 883-84 makes clear the close association of the terms for Chaucer. Earlier commentators insisted that this was in fact an instance of rime riche or "identical rhyme," but if it is so it is striking that it is the unique instance of the rhyme in Chaucer, whose works are full of occasions for hurt hearts. The essay argues that this is, instead, an instance of near-rhyme and that the confusion in scribal spellings of ME hurten(with ′u,′ ′0,′ ′i,′ ′y,′ and ′e′ ) suggests uncertainties about its root vowel that modem linguistic study has not clarified completely. If the rhyme of herte ("hurt") with herte ("heart") is, however, established by these lines in BD, then it is probably reasonable to ask about all the occasions where characters in the poem are hurt by emotional or physical distress. In the cases of A1cyone and the Man in Blak, the hurt is revealed plainly as the death of a loved one, and Alcyone′s death and the Man in Blak′s return "homwarde" offer contrasting responses to the realization and acknowledgement of their loss. In the case of the Narrator, however, the exact nature of his "hurt" is nowhere made clear and the questions this Jack of clarity raises for the reader remain unanswered when the poem declares its "hert-huntyng" done. Further examination of the Narrator′s character and his role in the poem may reveal him to be a physician himself in need of healing, and this reading of his character may identify him as an ancestor as much of Chaucer′s Pardoner as of the Pilgrim Narrator of Canterbury Tales.

• Journal of Broadcast Engineering
• /
• v.16 no.2
• /
• pp.190-206
• /
• 2011

We propose an adaptive combination scheme of intra and inter prediction modes, where uni-directional intra prediction, bi-directional intra prediction, and inter prediction method are adaptively selected in an EMB (extended macro block). For each EMB, after all inter blocks have been encoded and decoded, the reconstructed blocks are used as reference data for bi-directional intra prediction of other blocks. Whereas conventional intra coding scheme does not use the right and below side pixels of the current block as reference data, the proposed method uses those for bi-directional intra prediction mode. In this paper, we propose three advanced techniques; (a) filter design for bi-directional prediction, (b) adaptive coding order scheme which increases the chance to use the bi-directional intra prediction mode, (c) modification of syntax to represent coding order. The information for the coding order is informed to the decoder by using the modified syntax structure without adding any additional flag. The simulation results show that the proposed scheme reduces the BD-Rate by 0.5%, on average, compared to KTA.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.2
• /
• pp.285-294
• /
• 1992

Biochemical polymorphisms of sow's milk proteins, $\beta$-casein ($\beta$-CN), $\beta$-lactoglobulin ($\beta$-LG), post-lactoglobulin (post-LG), $\alpha$-lactalbumin ($\alpha$-LA) and X-protein, as genetic markers for major pig breeds (Landrace, Yorkshire, Duroc, Hampshire and cross bred) in Korea were determined by starch gel electrophoresis. Phenotype and gene frequencies at all marker loci were estimated and genetic differences among breed populations were analyzed. Three $\beta$-CN phenotypes (AA, AB and BB) controlled by two codominant alleles (${\beta}-CN^A$ and ${\beta}-CN^B$), four $\beta$-LG phenotypes (AA, AC, $AC^{\pm}$ and CC) controlled by two codominant alleles (${\beta}-LG^A$ and ${\beta}-LG^C$) and ten X-protein phenotypes (AA, BB, CC, DD, AB, AC, AD, BC, BD and CD) controlled by four codominant alleles ($X^A,\;X^B,\;X^C\;and\;X^D$) were identified. In addition, a genetically controlled polymorphism of post-LG was found for the first time in sow's milk protein. Three different phenotypes (AA, AB and BB) were designated $post-LG^A$ and $post-LG^B$. Of the five marker loci examined, $\alpha$-LA locus was observed to lack any individual variation in all breeds studied. All populations were in Hardy-Weinberg equilibrium for all loci. There were marked breed differences for phenotype and gene frequencies in the post-LG and X-protein marker loci. However, there were little differences between breeds in the gene frequencies at the $\beta$-CN and $\beta$-LG marker loci.

• Transactions of the Society of Information Storage Systems
• /
• v.1 no.2
• /
• pp.115-120
• /
• 2005

As a popularity of a portable digital device such as a cellular phone, a digital camera and a MP3 player is spreading, the demand of the mobile storage device increases rapidly. A bluray technology using 405nm laser diode and objective lens having high NA(Numerical Aperture), 0.85, satisfies a miniaturization and a high capacity which are the requirements of the portable device. To develop SFFOP(small form factor optical pickup), it is prerequisite to minimize the number of optical components and establish evaluation and assembly method of micro optical pickup system as well as mass production method of micro optical component. To minimize optical elements of optical pickup, there have been many researches to use P-HOE(Polarized Holographic Optical Element) due to its extremely small size and versatile function. However, P-HOE is handled and assembled very accurately in SFFOP. In this paper, static error signal detection method is developed for an alignment of P-HOE in SFFOP. Using developed static error signal detection method, P-HOE can be aligned very accurately with real time result of static error signals of pickup such as FES(focusing error signal) and TES(Tracking Error Signal). The developed static error signal detection method is verified by the evaluation of commercialized DVD Pickup. And finally. developed static error signal detection method is applied for the assembly of P-HOE in SFFOP system satisfies specification of BD(Blu-ray Disk).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.34 no.1
• /
• pp.36-48
• /
• 2008

To repair bone defects in the oral and maxillofacial field, bone grafts including autografts, allografts, and artificial bone are used in clinical dentistry despite several disadvantages. The purpose of this study was to evaluate new bone formation and healing in rat calvarial bone defects using hydroxyapatite (HA, $Ca_{10}[PO_4]_6[OH]_2,\;Bongros^{(R)}$, Bio@ Co., KOREA) and tricalcium phosphate (${\beta}-TCP,\;Ca_3[PO_4]_2$, Sigma-Aldrich Co., USA) mixed at various ratios. Additionally, this study evaluated the effects of type I collagen (Rat tail, BD Biosciences Co., Sweden) as a basement membrane organic matrix. A total of twenty, 8-week-old, male Sprague-Dawley rats, weighing 250-300g, were divided equally into a control group (n=2) and nine experimental groups (n=2, each). Bilateral, standardized transosseous circular calvarial defects, 5.0 mm in diameter, were created. In each experimental group, the defect was filled with HA and TCP at a ratio of 100:0, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, and 0:100 with or without type I collagen. Rats were sacrificed 4 and 8 weeks post-operation for radiographic (standardized plain film, Kodak Co., USA), histomorphologic (H&E [Hematoxylin and Eosin], MT [Masson Trichrome]), immunohistochemical staining (for BMP-2, -4, VEGF, and vWF), and elementary analysis (Atomic absorption spectrophotometer, Perkin Elmer AAnalyst $100^{(R)}$). As the HA proportion increased, denser radiopacity was seen in most groups at 4 and 8 weeks. In general radiopacity in type I collagen groups was greater than the non-collagen groups, especially in the 100% HA group at 8 weeks. No new bone formation was seen in calvarial defects in any group at 4 weeks. Bridging bone formation from the defect margin was marked at 8 weeks in most type I collagen groups. Although immunohistochemical findings with BMP-2, -4, and VEGF were not significantly different, marked vWF immunoreactivity was present. vWF staining was especially strong in endothelial cells in newly formed bone margins in the 100:0, 80:20, and 70:30 ratio type I collagen groups at 8 weeks. The calcium compositions from the elementary analysis were not statistically significant. Many types of artificial bone have been used as bone graft materials, but most of them can only be applied as an inorganic material. This study confirmed improved bony regeneration by adding organic type I collagen to inorganic HA and TCP mixtures. Therefore, these new artificial bone graft materials, which are under strict storage and distribution systems, will be suggested to be available to clinical dentistry demands.

• Korean Journal of Optics and Photonics
• /
• v.18 no.4
• /
• pp.246-255
• /
• 2007

The floating image system (FIS) is a device to display input source in the space between fast surface of the display and an observer and it provides pseudo 3D depth to an observer when input source as real object or 2D image was displayed through the optical lens system in the FIS. The Advanced floating image system (AFIS) was designed to give more effective 3D depth than existing FIS by adding front and rear depth cues to the displayed stereogram, which it was used as input source. The magnitude of disparity and size of stereogram were strongly related each other and they have been optimized for presenting 3D depths in a non-optical lens systems. Thus, if they were used in optical lens system, they will have reduced or magnified parameters, leading to problem such as providing incorrect 3D depth cues to an observer. Although the size of stereogram and disparity were demagnified by total magnifying power of optical system, the viewing distance (VD) from the display to an observer and base distance (BD) for the gap between the eyes were fixed. For this reason, the quantity of disparity in displayed stereogram through the existing FIS has not kept the magnifying power to the total optical system. Therefore, we proposed the methods to provide correct 3D depth to an observer by compensating quantity of disparity in stereogram which was satisfied to keep total magnifying power of optical lenses system by AFIS. Consequently, the AFIS provides a good floating depth (pseudo 3D) with correct front and rear 3D depth cues to an observer.