• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.371-374
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• 2004

저온동시 소성용(low temperature co-fired ceramics, LTCC) 마이크로파 유전체을 만들기 위해 $Ca(Li_{1/4}Nb_{3/4})O_3$ 마이크로파 유전체 세라믹스에 zinc-borosililcate glass를 첨가하여 소결 특성과 마이크로파 유전 특성을 조사하였다. $Ca(Li_{1/4}Nb_{3/4})O_3$과 $0.7Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$에 zinc-borosilicate를 $5{\sim}30wt%$ 첨가하여 소결한 결과 $875{\sim}925^{\circ}C$에서 동시 소성이 가능한 것으로 확인되었으며 zinc-borosilicate glass의 함량이 증가할수록 저온에서 소성이 가능하였지만 과량의 액상과 2차상이 형성되면서 유전율과 품질계수가 저하되는 경향을 나타내었다. $Ca(Li_{1/4}Nb_{3/4})O_3$에 5wt%의 zinc-borosilicate를 첨가하여 $900^{\circ}C$에서 소성한 결과 가장 우수한 유전 특성$(\epsilon_r=17.45,\;Q{\times}f_0=5487)$을 나타내었고, 유전율을 높이기 위해 $CaTiO_3$를 0.3mol% 첨가한 $0.7Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$에 10wt%의 zinc-borosilicate를 첨가하여 $925^{\circ}C$에서 소성한 결과 가장 우수한 유전특성$(\epsilon_r=44.92,\;Q{\times}f_0=5567)$을 나타내었다.

• Analytical Science and Technology
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• v.24 no.6
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• pp.527-532
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• 2011

IQ motif-containing GTPase-activating protein 1 (IQGAP1), which is a well-known $Ca^{2+}$-independent calmodulin (CaM) binding protein, is involved in various cellular functions such as cell proliferation and cell migration. IQGAP1 has four repeated IQ motifs, which are crucial for CaM binding. It has been shown that all four IQ motifs of IQGAP1 can bind to $Ca^{2+}$/CaM, while the third and fourth IQ motifs of IQGAP1 can bind to apoCaM. However, it has not been clear whether the CaM binding of IQ motifs of IQGAP1 was mediated directly or indirectly. In this study, we examined whether the binding between CaM and each IQ motif of IQGAP1 was direct in vitro. As a result, we found that IQ1 motif has a weak $Ca^{2+}$-dependent CaM binding. In contrast, IQ3 has a $Ca^{2+}$-dependent CaM binding. All other motifs have no significant CaM binding. We also found that IQ(2.7-3) and IQ(3.5-4.4) have CaM binding capacity. This finding indicates that IQ motifs of IQGAP1 plays a dynamic role via different motif interactions with $Ca^{2+}$/CaM or proCaM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.139-142
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• 2003

Microwave dielectric properties of $Ca(Li_{1/4}Nb_{3/4})O_3-CaTiO_3$ ceramic systems were investigated with calcination temperatures and amounts of $CaTiO_3$ in the range of 0.2 to 0.4mol. $Ca(Li_{1/4}Nb_{3/4})O_3$ ceramics having orthorhombic crystal structure could be synthesized at $750^{\circ}C$ and sintered well at $1250^{\circ}C$. They showed the dielectric constant of 26, quality factor($Q{\times}f_o$) of 13,000 and temperature coefficient of resonant frequency(${\tau}_f$) of $-49{\pm}2ppm/^{\circ}C$ With adding the $CaTiO_3$ amount the dielectric constant and ${\tau}_f$ increased due to the solute of $CaTiO_3$ but the quality factor decreased. The 0.7$Ca(Li_{1/4}Nb_{3/4})O_3-0.3CaTiO_3$ ceramic showed the dielectric constant of 44, quality factor($Q{\times}f_o$) of 12,000 and ${\tau}_f$ of $-9{\pm}1ppm/^{\circ}C$.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6241-6243
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• 2013

Objective: To explore the predictive value of tumor markers, including cancer antigen 72-4 (CA72-4), cancer antigen 15-3 (CA15-3) and cancer antigen 125 (CA125), in single or combined detection, for the diagnosis of ovarian cancer. Methods: 120 patients diagnosed with ovarian cancer from August 2011 to March 2013 and 80 patients diagnosed with benign ovarian tumors were enrolled in this test, along with 50 health examination women randomly selected from the database as controls. Serum levels of CA72-4, CA15-3 and CA125 in this study were determined by electrochemiluminescence (ECL). Results: Serum levels of CA72-4, CA15-3 and CA125 in ovarian cancer were higher than those in healthy group and benign group (P<0.01).The sensitivity of combined detection of those three tumor markers for diagnosis of ovarian cancer was obviously higher than with single detection with each marker (P<0.01). Conclusions: CA72-4, CA15-3 and CA125 could be a good combination in the diagnosis of ovarian cancer. Patients whose tumor markers continue to increase should be highly suspected of malignancy.

• Journal of Animal Science and Technology
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• v.64 no.5
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• pp.871-884
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• 2022

Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl₂ and CaCO₃) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0-14; phase 2, days 15-28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased (p < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group (p <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl₂ diet group compared with the case in the CaCO₃ diet group (p < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Cl^- levels were higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). The bicarbonate (HCO_3-), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Hematocrit increased as the Ca level decreased (p < 0.05). The HCO_3- interacted with the Ca sources and thus, affected the Ca levels (p < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl₂ appeared to be a better Ca source than CaCO₃ because of the greater digestibility of CP, Ca, and P, and improved EB.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.337-340
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• 1999

Luminescence of bismuth activated CaS, CaS:Bi, prepared in sodium polysulfide is studied. Excitation spectrum of CaS:Bi shows a band at 350 nm due to the recombination process between holes in Na+Ca2+ and electrons in conduction bands, in addition to bands at 260 nm from band gap of CaS, and at 320 nm (1S0→1P1) and at 420 nm (1S0→3P1) from electronic energy transitions of Bi. Emission band at 450 nm is from 3P1→1S0 transition of Bi3+, bands at 500 nm and 580 nm correspond to recombinations of electron donors (Bi3+Ca2+ and VS2-) with acceptors (VCa2+ and Na+Ca2+). Emission band of 3P1→1S0 transition is shifted to longer wavelength from CaS:Bi to BaS:Bi, due to the increase of the Stokes shift by the decrease of the crystal field parameter from CaS:Bi to BaS:Bi.

• Korean Journal of Materials Research
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• v.16 no.1
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• pp.44-49
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• 2006

Effects of doping rare earth element on Ln site of $Ln_{0.7}Ca_{0.3}MnO_3$ (Ln=Nd, Sm and La) were examined from sintering behavior, structure and magnetic properties. Sintering reactions proceeded rapidly in order of $La_{0.7}Ca_{0.3}MnO_3>Nd_{0.7}Ca_{0.3}MnO_3>Sm_{0.7}Ca_{0.3}MnO_3$. This result can be explained by diffusivity of metal cation. Size of a-axis increased as following order of La$Nd_{0.7}Ca_{0.3}MnO_3$, 93K for $Sm_{0.7}Ca_{0.3}MnO_3$ and 225K for $La_{0.7}Ca_{0.3}MnO_3$ were obtained. This result coincides with change of Mn-O bond length causing by a-axis lattice constant.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.1-5
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• 1999

The rare-earth ions ($R^{3+}$, R=Nd, Er) doped $CaF_{2}$ layers have been grown on $CaF_{2}$ (111) substrate by molecular beam epitaxy. The surface structure and the crystallinity of $CaF_{2}:R^{3+}$ layers depending on the doping concentration of $R^{3+}$ and layer thickness were studied by reflection high-energy electron diffraction (RHEED). In aspect of application as buffer layer in semiconductor-related hybrid structure, the lattice displacement between $CaF_{2}:R^{3+}$ layers and $CaF_{2}$ (111) substrate was investigated by X-ray rocking curve analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.195-195
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• 2008

CAS계 유리에 $CaCO_3-Al_2O_3$ 혼합물 및 화합물을 10, 30 wt% 첨가하여 저온 소걸 및 마이크로파 유전 특성을 고찰하였다. CAS계 유리의 연화온도는 $841^{\circ}C$ 이며, CAS계 유리에 $CaCO_3$ 와 30 wt%의 $CaCO_3-Al_2O_3$ 혼합물을 melting되며, 10 wt%의 $CaCO_3$, $Al_2O_3$, $1CaCO_3-1Al_2O_3$ 혼합물 및 $CaAl_2O_4$ 화합물를 10 wt% 첨가하였을 때 $900^{\circ}C$ 이하에서 소걸이 가능하였다. 복합체의 XRD 상 분석 결과, CaCO3를 첨가하였을 때에는 모든 조성이 비정질을 나타내었고, $Al_2O_3$와 $1CaCO_3-1Al_2O_3$ 혼합물은 $Al_2O_3$ 결정상이 생성되었고, $CaAl_2O_4$ 화합물은 $CaAl_2Si_2O_8$의 hexagonal와 anorthite 결정상이 생성되었다. 따라서 CAS-10 (A, C-A, CA) 복합체는 $900^{\circ}C$에서 각각 유전율 ($\varepsilon_r$) 6.4, 6.9, 5.15 와 품질계수 ($Q^*f$) 2,400, 1,500, 3,000의 마이크로파 유전 특성을 나타내어 LTCC 기판 재료로 사용이 가능하며, 특히 $CaAl_2O_4$ 화합물을 사용하였을 때 가장 우수한 유전 특성을 나타내는 것을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.459-465
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• 2000

3CaO.3Al2O3.CaSO4(C4A3)clinker was prepared by solid state reaction and then its hydration property was investigated. C4A3 clinker was fired at various temperatures in the range of 700~135$0^{\circ}C$. The hydration of it was studied by XRD, DSC, Solid-state 27Al MAS NMR and SEM. According to the results, the Ca4A3 clinker was produced by reacting calcium aluminates with CaSO4 and Al2O3 and C4A3 was formed as a main phase after calcining at 120$0^{\circ}C$. The hydration products were mainly calcium monosulfoaluminate hydrate and Al(OH)3, and they were produced after 2hrs of hydration. However the hydration rate was about 74% at 3days.