• Transactions on Electrical and Electronic Materials
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• v.1 no.1
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• pp.26-31
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• 2000

The ~1540 nm $^4$ $I_{13}$ 2/ longrightarro $w^4$ $I_{15}$ 2/ emissions of E $r^{3+}$ in Er-implanted GaN annealed at temperatures in the 400 to 100$0^{\circ}C$ range were investigated to gain a better understanding of the formation and dissociation processes of the various E $r^{3+}$ sites and the recovery of damage caused by the implantation with increasing annealing temperature ( $T_{A}$).The monotonic increase in the intensity of the broad defect photoluminescence(PL) bands with incresing $T_{A}$ proves that these are stable radiative recombination centers introduced by the implantation and annealing process. Theser centers cannot be attributed to implantation-induced damage that is removed by post-implantation annealing. Selective wavelength pumpling of PL spectra at 6K reveals the existence of at least nine different E $r^{3+}$ sites in this Er-implanted semiconductor. Most pf these E $r^{3+}$ PL centers are attributed to complexed of Er atoms with defects and impurities which are thermally activated at different $T_{A}$. Only one of the nine observed E $r^{3+}$ PL centers can be pumped by direct 4f absorption and this indicates that it is highest concentration E $r^{3+}$ center and it represents most of the optically active E $r^{3+}$ in the implanted sample. The fact that this E $r^{3+}$ center cannot be strongly pumped by above-gap light or broad band below-gap absorption indicates that it is an isolated center, i.e not complexed with defects or impurities, The 4f-pumped P: spectrum appears at annealing temperatures as low as 40$0^{\circ}C$, and although its intensity increase monotonically with increasing $T_{A}$ the wavelengths and linewidths of its characteristic peaks asre unaltered. The observation of this high quality E $r_{3+}$PL spectrum at low annealing temperatures illustrates that the crystalline structure of GaN is not rendered amorphous by the ion implantation. The increase of the PL intensities of the various E $R_{3+}$sites with increasing $T_{A}$is due to the removal of competing nonradiative channels with annealing. with annealing.annealing.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.63-65
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• 1999

Although many pharmaceutically useful proteins are produced in E. coli expression system, it is very are rare for the system to be used in the production of diagnostic antigen due to a major problem, i.e., false-positive reaction of e. coli host-derived proteins contaminating purified diagnostic antigen with human sera. The N (nucleocapsid) protein of Seoul virus causing haemorrhagic fever with renal syndrome (HFRS) was produced in E. coli BL21 (DE3), and used for the detection of N protein-specific antibodies in human sera. Using the N protein as a diagnostic antigen of HFRS, the false-positive reaction was cleared by merely mixing the test sera with the extract of E. coli host strain not harboring expression plasmid.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.930-935
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• 2009

This paper describes a miniaturezed metamaterial BT chip antenna for mobile devices. The size of the proposed antenna is $3.0\;mm(W){\times}2.0\;mm(L){\times}1.2\;mm(H)$. And it is fabricated by chip type. The zeroth-order resonant properties are analyzed by magnitude and phase distributions of the surface current using surface current scanning system. The antenna offers omni-directional radiation patterns and measured 3D average gain is over - 1.7 dBi.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.69-73
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• 2010

The melt grafting of unsaturated silanes onto polypropylene (PP) in a twin-screw extruder and crosslinking in hot water were studied to enhance impact strength of polypropylene. The influence of grafting formulations on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. 3-methacryloylpropyltrimethoxysilane (VMMS) unsaturated silane monomer was used. Benzoyl peroxide, (BPO) and Dicumyl peroxide (DCP) were used as an initiator. When benzoyl peroxide (BPO) was used as an initiator, higher gel percentage and impact strength than those of DCP has been observed. The maximum impact strength was obtained with 0.7 phr of BPO and 2phr of VMMS. The value is 8.7 kgf-cm/cm and it is on a parity with the value of with 20 phr of EOR mixed to PP.

• Polymer Science and Technology
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• v.9 no.3
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• pp.216-223
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• 1998

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.60-60
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• 2008

We manufactured Liquid Crystal Polymer (LCP) and (1-x)$BaTiO_3-xSrTiO_3$(BST) ceramic composites and investigated dielectric properties to use as embedded capacitor in printed circuit boards and replace LTCC substrates. The dielectric properties of these composites are varied with volume fraction of BST and ratios of BT/ST. Dielectric constants are in the range of 3~28. In addition, we could get low TCC and High Q value that could not achieve in other ceramic-polymer composites. Especially, in composite with x=0.4 and 50vol% BST, the dieletric constant and Q-value are 27 and 300, respectively. And more TCC is -116~145ppm/$^{\circ}C$ in the temperature range of -55~$125^{\circ}C$. We think that this composites can be used high-Q substrate material like LTCC and embedded temperature compensation capacitor in printed circuit boards.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.168-173
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• 2000

Two diterpenes and one new sucrose isovaleryl ester having inhibitory effects on melanogenesis in B16 mouse melanoma were isolated from Euphorbiae Lathyridis Semen which has been used in traditional medicine for cancer, tumors and warts. New sucrose isovaleryl ester was identified as ${\alpha}-D-glucopyranoside$, $3,4,6-tris-O-(3-methyl-l-oxobutyl)-{\beta}-D-fructofuranosyl$, 2,6-bis(3-methylbutanoate) and two diterpenes were identified as ingenol-20-palmitate and 5,10-diacetyl-3-benzoyllathyrol$(Euphorbia\;factor\;L_3)$ from their spectral data.

• Journal of Korean Neurosurgical Society
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• v.63 no.5
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• pp.550-558
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• 2020

To perform a systematic review of the data collected from case-control studies conducted earlier to investigate the correlation between E-selectin S128R polymorphism and ischemic stroke (IS) risk among the Chinese population. The PubMed, Web of Science, Chinese biomedical literature database (CBM), Chinese databases China National Knowledge Infrastructure (CNKI), WanfangData knowledge service platform (Wanfang Data), and information resource integration service platform (VIP) Databases were searched to retrieve case-control studies on the correlation between E-selectin gene S128R polymorphism and IS from the inception of the database till June 2019. The literature was screened, data were extracted, the risk of bias was reviewed, and the studies included were assessed independently by two reviewers. Stata ver. 12.0 software (Stata Corp LLC, College Station, TX, USA) was used to perform the meta-analysis. A total of 2907 cases from eight case-control studies involving 1478 IS patients and 1429 controls were included in this study. The R allele and RS genotype in E-selectin were found to be associated with the risk of IS as per the results of the meta-analysis (R vs. S : odds ratio [OR], 2.75; 95% confidence interval [CI], 2.15-3.51; p<0.00001; RS vs. SS : OR, 2.50; 95% CI, 1.95-3.19; p<0.00001; RR+RS vs. SS : OR, 2.85, 95% CI, 2.21-3.67; p<0.00001). The E-selectin gene S128R polymorphism is likely related to IS based on the results of a meta-analysis in the Chinese population, and the R allele and RS genotype of E-selectin may be IS risk factors.

• Journal of the Chungcheong Mathematical Society
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• v.31 no.4
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• pp.369-379
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• 2018

Let ${\mathbb{H}}_3$ be the 3-dimensional Heisenberg group equipped with a left-invariant metric. In this paper we calculate the volumes of geodesic balls in ${\mathbb{H}}_3$. Let $B_e(R)$ be the geodesic ball with center e (the identity of ${\mathbb{H}}_3$) and radius R in ${\mathbb{H}}_3$. Then, the volume of $B_e(R)$ is given by $$Vol(B_e(R))={\frac{\pi}{6}}\{-16R+(R^2+6){\sin}\;R+(R^3+10R){\cos}\;R+(R^4+12R^2){\int\nolimits_0^R}\;{\frac{{\sin}\;t}{t}}dt\}$$.

• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.401-404
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• 2008

Willemite ($Zn_2SiO_4$) are a wide range of applications such as a phosphor host and an important crystalline phase in glass ceramics, electrical insulators, glazes, and pigments. In this study, Willemite precursors were synthesized with zinc silicate gels from mixture of zinc nitrate solution and various sodium silicate solution by the geopolymer technique. To examine the crystallization behavior, precursors were have been monitored by the XRD. A pure willemite phase was obtained at $900^{\circ}C$. TEM investigations revealed that the sample with 50 nm particle size was obtained via heat-treated at $900^{\circ}C$ for W-3.