• 한국세라믹학회지
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• 제23권4호
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• pp.55-61
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• 1986

Phosphosilicate glass(PSG) films have been used as fusable deposited dielectrics in silicon gate MOS integrated circuits. But in this experiment BPSG(borophosphosilicate glass) will be optimized for more efficient utilization of the reactants. The BPSG films were deposited on silicon wafers by the oxidation of the hydrides at 430$^{\circ}$C in conventional atmospheric-pressure chemical-vapor-deposition (CVD) systems. Physical and chemical properties of CVD BPSG films have been characterized both for as-deposited and for fused films The. relationship between deposited BPSG film composition and infra-red absorption solution etch rate and fusion temperature is discussed and examples of BPSG composition that can be fused at 900~95$0^{\circ}C$ and 800~85$0^{\circ}C$ are given. In addition to having lower fusion temperature than PSG films BPSG films have lower as-deposited intrinsic tensile stress and low aqueous chemical etch rate they have been considered for applications where these characteristics are advantageous.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.181-185
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• 2008

The new concept for liquefaction of natural gas has been designed and simulated in this paper. Conventional liquefaction cycles are usually composed with Joule-Thomson valves at lower temperature refrigerant cycle. The new concept of natural gas liquefaction is discussed. The main difference with conventional liquefaction process is the presence of the turbine at low temperature of MR (mixed refrigerant) cycle. The turbine acts as expander but also as an energy generator. This generated energy is provided to the compressor which consumes energy to pressurize refrigerants. The composition of the mixed refrigerant is investigated in this study. Components of the refrigerant are methane, propane and nitrogen. Composition for new process is traced with Aspen HYSYS software. LNG heat exchangers are analyzed for the new process. Heating and cooling curves in heat exchangers were also analyzed.

• 한국포장학회지
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• 제9권1호
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• pp.19-24
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• 2003

We study on the phase diagram of the polymer blend. For this purpose, one PS (polystyrene) and two PI(polyisoprene) were employed whose molecular weights were low enough to make the experimental determinations possible. The weight-average molecular weight(Mw) of PS was 2514, and Mws of two PIs were 2700. Interaction energy density (IED) of the Flory-Huggins lattice theory was defined as a function of temperature and composition, and the consequent equations for the binodal, and critical points were derived. By fitting the experimental binodal points to the derived binodal curve with a nonlinear regression method, the expression for the IED was determined. And the expression for the IED obtained from this study was compared with those reported in the literatures. Also were discussed the importance of accuracy in the expression the IED, and the IED's dependency on the temperature, composition and molecular weights.

• Animal Bioscience
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• 제34권1호
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• pp.93-101
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• 2021

Objective: Temperature could influence protein and amino acid deposition as well as gut microbiota profile and composition. However, the specific effects of ambient temperature on amino acids deposition and gut microbiota composition remain insufficiently understood. Methods: A total of 300 one-day-old Avian broilers were randomly divided into three groups and reared at high, medium, and low temperature (HT, MT, and LT), respectively. Breast muscle and fecal samples were collected for amino acid composition analysis and 16S rRNA gene sequence analysis. Results: Our data showed that compared to the MT group, there was a decrease of muscle leucine and tyrosine (p<0.05), as well as an increase of methionine in the HT group (p<0.05) and a decrease of serine in the LT group. Examination of microbiota shift revealed that at genus level, the relative abundance of Turicibacter and Parabacteroides was increased in the HT group (p<0.05) and that the relative abundances of Pandoraea, Achromobacter, Prevotella, Brevundimonas, and Stenotrophomonas in the LT group were higher than those in the MT group (p<0.05). In addition, there were substantial correlations between microbes and amino acids. In the HT group. Turicibacter was negatively correlated with aspartic acid and tyrosine, whereas Parabacteroides was positively correlated with methionine (p<0.05). In the LT group, there were multiple positive correlations between Achromobacter and arginine, isoleucine or tyrosine; between Prevotella and cysteine or phenylalanine; between Brevundimonas and cysteine; and between Stenotrophomonas and cysteine as well as a negative correlation between Stenotrophomonas and serine. Conclusion: Our findings demonstrated that amino acid content of breast muscle and intestinal microbiota profile was affected by different ambient temperatures. Under heat exposure, augmented abundance of Parabacteroides was correlated with elevated methionine. Low temperature treatment may affect muscle tyrosine content through the regulation of Achromobacter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.33-34
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• 2005

In this study, in odor to develop low temperature sintering multilayer piezoelectric actuator and ultrasonic vibrator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$ and $Na_2CO_3$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the addition of dopant CuO and $Fe_2O_3$, respectively. The CuO added PMN-PNN-PZT ceramics improved mechanical quality factor Qm due to the acceptor doping effect. And also, $Fe_2O_3$ reacted as softner in this composition system in addition to the increase of grain size and sinterability. Taking into consideration electromechanical coupling factor kp of 0.62, dielectric constant $\varepsilon_r$, of 1275, Piezoelectric $d_{33}$ constant of 377[pC/N] and mechanical quality factor Qm of 975, it was concluded that the ceramics with the $Fe_2O_3$, added composition sintered at 900[$^{\circ}C$] were best for the multilayer piezoelectric actuator and ultrasonic vibrator application.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.566-569
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• 1999

The blue emitting BAM Phosphor Particles with various compositions were Prepared by the spray Pyrolysis. The effect of composition on the morphology of BAM particles was Investigated. In the case of BaMgAl$_{10}$ /O$_{22}$ : Eu$^{2+}$, the morphology of particles with sphericity and non-aggregation characteristics disappeared after post-treatment at 1400 $^{\circ}C$ for 3 hrs. On the other hand, the ocher composition particles except BaMgAl$_{10}$ /O$_{22}$ : Eu$^{2+}$ maintained their original morphology after post-treatment, even if the particles were prepared at low temperatures in the spray pryrolysis. The BAM particles with MgAl$_{2}$/O$_4$as intermediate material at low post-treatment temperature had high thermal stability and maintained sphericity of particles after post-treatment. All the samples had main omission peak at 450 nm, which corresponds to blue emission. The optimum post-treatment temperature of BAM:Eu$^{2+}$ particles for the maximum PL(photoluminescence) intensity in the spray pylolysis was 1200 $^{\circ}C$ because of high crystallinity, Phase-Purity, and good morphology.ology.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.224-225
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• 2007

The Low dielectric properties of epoxy/Annealing $SiO_2$ composites using Annealing new material of nanosized amorphous particles were investigated as function frequency, temperature and filler contents composition. The dielectric constant decrease with increasing frequency and also increase with increasing ambient temperature. The dielectric constant decrease with increase annealing filler contents for epoxy base. The result of x-ray diffraction could obtained single crystal of annealing $SiO_2$ from 500nm amorphous $SiO_2$ powder.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.141-144
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• 2011

We report the synthesis of $SrTiO_3$, $BaTiO_3$ and $Ba_xSr_{1-x}TiO_3$ (BST) nanoparticles (NPs) in various compositions (x = 0.25, 0.5 and 0.75) by an inorganic sol-gel method under a basic condition. Highly crystalline nanoparticles were formed at the reaction temperature of 25 - $100^{\circ}C$ from a stabilized titanium alkoxide in tetramethylammonium hydroxide (TMAH) and barium or strontium acetate in aqueous solution. Morphology and particle structure of the synthesized BST NPs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The BST nanoparticles in various compositions were monodispersed without mutual aggregation, and their average sizes were in the range of 70 - 80 nm. Furthermore, they showed highly crystallized perovskite phase over the whole composition range from $SrTiO_3$ to $BaTiO_3$. We also proposed a mechanism for the low-temperature formation of BST NPs.

• 한국분말재료학회지
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• 제30권4호
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• pp.339-345
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• 2023

This study investigates the melting point and brazing properties of the aluminum (Al)-copper (Cu)-silicon (Si)-tin (Sn) alloy fabricated for low-temperature brazing based on the alloy design. Specifically, the Al-20Cu-10Si-Sn alloy is examined and confirmed to possess a melting point of approximately 520℃. Analysis of the melting point of the alloy based on composition reveals that the melting temperature tends to decrease with increasing Cu and Si content, along with a corresponding decrease as the Sn content rises. This study verifies that the Al-20Cu-10Si-5Sn alloy exhibits high liquidity and favorable mechanical properties for brazing through the joint gap filling test and Vickers hardness measurements. Additionally, a powder fabricated using the Al-20Cu-10Si-5Sn alloy demonstrates a melting point of around 515℃ following melting point analysis. Consequently, it is deemed highly suitable for use as a low-temperature Al brazing material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.220-223
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• 2005

We studied the effect of composition, processing, and sintering temperature on the microwave properties of $Mg_{3-x}Co_x(VO_4)_2$ system which is applicable to LTCC. When $Mg_{3-x}Co_x(VO_4)_2$ was fabricated by solid-state reaction process and sintered at the temperature range of $800\sim910^{\circ}C$, it was found that the optimum composition of x was 2 at which microwave properties of 910$^{\circ}C$-sintered one were as follows: $Q\times f_0\sim55,200GHz$ and $\varepsilon_r\sim10$. When $(MgCo_2)(VO_4)_2$ was fabricated by sol-gel process and sintered at 800$^{\circ}C$, $Q\timesf_0$was 34,400GHz which is much high compared to those fabricated by solid-state reaction process at the same sintering temperature.