간장게장은 우리나라 전통 식품 중의 하나로 생 꽃게를 세척한 후 간장소스를 첨가하고 저온에서 숙성시켜 포장 하여 상업적으로 판매하고 있다. 하지만, 간장게장 제조 특성 상 열처리를 하지 않기 때문에, 간장게장의 미생물학적 품질을 유지하는데 어려움이 따른다. 따라서 본 연구에서는 원물 꽃게의 초기 미생물 저감화를 위해 여러 살균세척제의 효능을 비교하고 저장 중 간장게장 제품의 미생물학적 품질을 유지하기 위해 키토산의 항균 효능을 평가하였다. 먼저, 상온에서 생 꽃게를 염소수(50 mg/L), 과초산(40 mg/L), acetic acid (5%), lactic acid(5%)에 각각 10분간 침지시켜 일반세균수를 분석하였다. 결과를 살펴보면, 여러 살균세척제 중 5% acetic acid 세척이 생 꽃게에 존재하는 일반세균수를 약 1.5 log CFU/g까지 감소시켜 가장 효과적인 것으로 나타났다. 키토산 효능을 평가하기 위해 현재 상업적으로 제조되고 있는 간장게장(방법 1; 전해수 세척), 5% acetic acid로만 세척된 꽃게(방법 2), 5% acetic acid로 세척된 꽃게에 0.5%(방법 3)와 1%(방법 4)의 수용성 키토산이 첨가된 간장으로 제조된 간장게장을 각각 4oC와 12oC에서 최대 30일까지 저장하면서 일반세균수, 대장균군 및 대장균수를 측정하였다. 12oC에서 저장된 간장게장의 일반세균 수는 7일이 지났을 때 약 8 log CFU/g까지 증가하였다. 4oC의 경우, 1% 키토산이 첨가된 군(방법 4)에서 20 일 동안 약 2.9 log CFU/g까지만 증가한 것으로 나타나 키 토산 무첨가군(방법 1과2)과 0.5% 첨가군(방법 3)(4.2~4.5 log CFU/g)에 비하여 훨씬 효과적이었다. 본 결과에 따라, 생 꽃게를 5% acetic acid로 세척한 후 간장게장에 1% 키토산을 첨가하여 냉장온도에서 저장한다면 간장게장 제품의 미생물학적 품질 향상에 큰 도움이 될 것으로 여겨진다.

There are several manufacturing techniques for developing thermionic cathodes for vacuum ultraviolet(VUV) ionizers. The triple alkaline earth metal emitters(Ca-Sr-Ba) are formulated as efficient and reliable thermo-electron sources with a great many different compositions for the ionizing devices. We prepare two basic suspensions with different compositions: calcium, strontium and barium. After evaluating the electron-emitting performance for europium, gadolinium, and yttrium-based cathodes mixed with these suspensions, we selected the yttrium for its better performance. Next, another transition metal indium and a lanthanide metal neodymium salt is introduced to two base emitters. These final composite metal emitters are coated on the tungsten filament and then activated to the oxide cathodes by an intentionally programmed calcination process under an ultra-high vacuum(~10-6 torr). The performance of electron emission of the cathodes is characterized by their anode currents with respect to the addition of each element, In and Nd, and their concentration of cathodes. Compared to both the base cathodes, the electron emission performance of the cathodes containing indium and neodymium decreases. The anode current of the Nd cathode is more markedly degraded than that with In.

This study was conducted to evaluate the efficacy of mulberry cake mixed diet on larval growth of Protaetia brevitarsis. As a result of adding mulberry cake to oak fermented sawdust and mulberry fermented sawdust, the survival rate of P. brevitarsis larvae were higher than those of the control when mass rearing larvae. When fed oak fermented sawdust with 3, 5% and 10% of mulberry cake, the cumulative proportion of larvae over 2.5g was 92.9% at 65 days, 90.8% at 55 days, and 96.3% at 45 days after rearing at 25±1℃, respectively. When fed mulberry fermented sawdust with 3%, 5% and 10% of mulberry cake, the cumulative proportion of larvae over 2.5g was 86.2% at 85 days, 90.7% at 75 days, and 91.5% at 75 days after rearing at 25±1℃, respectively.

This study investigates the effect of MnO2 and CuO as acceptor additives on the microstructure and piezoelectric properties of 0.96(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3-0.04BaZrO3, which has a rhombohedral-tetragonal phase boundary composition. MnO2 and CuO-added 0.96(K0.5Na0.5)0.95Li0.05Nb0.93Sb0.07O3-0.04BaZrO3 ceramics sintered at a relatively low temperature of 1020 oC show a pure perovskite phase with no secondary phase. As the addition of MnO2 and CuO increases, the sintered density and grain size of the resulting ceramics increases. Due to the difference in the amount of oxygen vacancies produced by B-site substitution, Cu ion doping is more effective for uniform grain growth than Mn ion doping. The formation of oxygen vacancies due to B-site substitution of Cu or Mn ions results in a hardening effect via ferroelectric domain pinning, leading to a reduction in the piezoelectric charge coefficient and improvement of the mechanical quality factor. For the same amount of additive, the addition of CuO is more advantageous for obtaining a high mechanical quality factor than the addition of MnO2.

Cr-Al alloys are attracting attention as oxidation resistant coating materials for high temperature metallic materials due to their excellent high temperature stability. However, the mechanical properties and oxidation resistance of Cr-Al alloys can be further enhanced, and such attempts are made in this study. To improve the properties of Cr-Al alloys, Si is added up to 5 wt%. Casting specimens with different amounts of Si content are prepared by a vacuum arc remelting method and isothermally heated under steam conditions at 1,100oC for 1 hour. The as-cast microstructure of low Si alloys is mainly composed of only a Cr phase, while Al8Cr5 and Cr3Si phases are also observed in the 5% Si alloy. In the high Si alloy, only Cr and Cr3Si phases remain after the isothermal heating at 1,100oC. It is found that Si additions slightly decrease the oxidation resistance of the Cr-Al alloy. However, the microhardness of the Cr-Al alloy is observed to increase with an increasing Si content.

본 연구에서는 활용도가 낮은 식자원의 부가가치 부여라는 목적으로 연구를 진행하였다. 0, 2, 4, 6 및 8%로 비지첨가량을 달리하여 제조한 국수의 수분 결합력, 색도, 국수의 표면 구조 및 물성실험을 진행하여 비지 첨가 국수의 제면특성을 확인하였다. 수분 결합력은 비지 분말의 첨가에 따라 유의하게 증가하였다. 국수의 명도(L)는 비지 분말의 농도가 증가함에 따라 유의적인 감소패턴을 보였으며, 적색도(a)와 황색도(b)는 유의적 변화가 없었다. 표면의 미세구조를 확인한 결과, 비지 분말의 농도가 증가함에 따른 공극의 특이적인 변화 확인할 수 없었다. 조리 전 생면의 물성을 확인한 결과, 경도, 부착성, 탄력성, 점착성 및 씹힘성은 비지 분말이 첨가함에 따라 상승하는 경향을 나타낸 반면, 응집성은 감소하는 경향을 나타내었다. 조리면의 경우, 경도, 탄력성 및 부착성은 비지분말 첨가에 따른 상승경향을 나타낸 반면, 응집성은 감소하는 경향을 나타내었다. 점착성과 씹힘성은 유의적인 차이가 없었다. 이러한 제면특성을 종합 판단하여 국수의 제조시 비지분말의 첨가는 4%가 가장 좋은 것으로 판단되었다.

Cordierite composed of an alumina-silica-magnesia compound has a low coefficient of thermal expansion(CTE) and excellent thermal shock resistance. It also has a low dielectric constant and high electrical insulation. However, due to low mechanical strength, it is limited for use in a ceramic heater. In this study, ZrO2 is added to an 80 wt% cordierite-20 wt% mullite composition, and the effect of ZrO2 addition on the mechanical strength and thermal shock resistance is investigated. With an increasing addition of ZrO2, cordierite-mullite formed ZrO2, ZrSiO4 and spinel phases. With sintering conducted at 1400 °C with the addition of 5 wt% ZrO2 to 80 wt% cordierite-20 wt% mullite, the most dense microstructure forms along with an excellent mechanical strength with a 3-point flexural strength of 238MPa. When this composition is quenched in water at ΔT = 400℃ , the 3-point flexural strength is maintained. Moreover, when this composition is cooled from 800℃ to air, the 3-point flexural strength is maintained even after 100 cycles. In addition, the CTE is measured as 3.00 × 10−6·K−1 at 1000℃ . Therefore, 80 wt% cordierite-20 wt% mullite with 5 wt% ZrO2 is considered to be appropriate as material for a ceramic heater.

In our previous studies, the cardiac xenotransplantation from an alpha-1,3-galactosyltransferase knockout pig (GT-MCP-MCP) to cynomolgus monkeys showed a mean survival of 38 days. The objective of this study is to genetically upgrade the GT-MCP-MCP pig, to further enhance membrane cofactor protein (MCP) expression and to express an endothelial specific thrombomodulin (TBM). MCP is a complement regulatory protein and TBM is a coagulation inhibitor. As the dicistronic cassette for wild-type-based MCP and TBM concurrent expressions does not show any increase of MCP, we optimized the MCP codon usage (mMCP) and substituted mMCP for MCP. When the mMCP-TBM cassette was transfected to HeLa cells, we were able to find an increased expression of MCP and endothelial cell-specific TBM expression. The cassette was then transfected into ear-skin fibroblasts isolated from one-month-old #23-4 of a GT-MCP-MCP pig, and the cell populations expressing MCP were obtained by MACS cell sorting. We performed a single cell culture of the selected cells, and obtained clones over expressing 90% MCP. The cells of a clone were used as a donor for nuclear transfer and generated GT-MCP/-MCP/mMCP/TBM pig. The transgenic pig was confirmed to be carrying the cells expressing MCP and functioning as an inhibitor against the cytotoxic effect of normal monkey serum, comparable with donor cells. Thus, we believe that the GT-MCP/-MCP/mMCP/TBM transgenic pig would be potential for the prolongation of xenograft survival in the recipients.

The effect of water vapor addition on the ignition delay of iso-octane/air mixture was numerically investigated with detailed chemical reaction mechanism. The Chemkin-III was utilized to evaluate the delay time of autoignition for isobaric conditions. By dilution effect and thermal effect, water vapor addition increases the ignition delay time. However, the chemical effect by adding water vapor makes the ignition delay shortened. The ignition delay by the chemical effect is reduced by two ways. Dissociation of water vapor increases the quantities of OH and H. One way is that OH directly makes the rate of iso-octane oxidation reaction 2 increase. The other is that HO2 is produced more by three-body reaction, H+O2+M →HO 2+M, which makes the rate of iso-octane oxidation reaction 3 increase. All trends of three effects are similar according to water vapor addition.

ZnO micro/nanocrystals are formed by a vapor transport method. Mixtures of ZnO and TiO powders are used as the source materials. The TiO powder acts as a reducing agent to reduce the ZnO to Zn and plays an important role in the formation of ZnO micro/nanocrystals. The vapor transport process is carried out in air at atmospheric pressure. When the weight ratios of TiO to ZnO in the source material are lower than 1:2, no ZnO micro/nanocrystals are formed. However, when the ratios of TiO to ZnO in the source material are greater than 1:1, the ZnO crystals with one-dimensional wire morphology are formed. In the room temperature cathodoluminescence spectra of all the products, a strong ultraviolet emission centered at 380 nm is observed. As the ratio of TiO to ZnO in the source material increases from 1:2 to 1:1, the intensity ratio of ultraviolet to visible emission increases, suggesting that the crystallinity of the ZnO crystals is improved. Only the ultraviolet emission is observed for the ZnO crystals prepared using the source material with a TiO/ZnO ratio of 2:1.

This study was conducted to investigate the quality characteristics of peach jelly following the addition of various gelling agents (locust bean gum, carrageenan, xanthan gum). The various gelling agents were added to peach jelly at five levels (1.0, 1.5, 2.0, 2.5 and 3.0%), after which their effects on physicochemical properties, textural properties and sensory qualities were investigated. The total titratable acidity (TTA) of peach jelly was decreased with increases in gelling agent. Additionally, the sweetness and pH of peach jelly increased significantly as the amount of various gelling agents increased. Moreover, the lightness (L-value), redness (a-value) and yellowness (b-value) of peach jelly was decreased as the amount of gelling agent. Furthermore, the hardness, gumminess and chewiness of the peach jelly increased as the amount of gelling agent increased. Finally, the overall acceptance was higher for jelly containing 2.0% added gelling agent than for other samples. Based on the results of this study, it is recommended that mixed gelling agents be added to peach jelly at 2.0%.

목적: 목적: 최근 근시의 진행을 억제하기 위하여 청소년기 학생들에게 누진렌즈가 처방되고 있다. 그러나 중간 영역의 좁은 시야로 인해 누진렌즈 착용시 영어 및 중국어 문자의 가독성이 저하될 것으로 예상할 수 있다. 이 연구의 목적은 단초점 렌즈를 착용할 때와 누진렌즈를 착용 할 때, 영어와 중국어 문자의 가독성을 비교하는 것이다. 방법: 총 40 명의 피검자가 이 연구에 참여하였다. 피검자들은 누진렌즈 또는 단초점 렌즈를 착용한 상태에서, 영어 또는 중국어 텍스트를 읽을 때 지정된 글자를 찾도록 요구받았다. 주어진 텍스트를 읽는데 걸린 시간을 측정하고, 피검자가 누진렌즈를 착용한 경우와 단초점 렌즈를 착용한 경우를 비교하였다. 텍스트를 읽는데 걸린 시간을 가독성의 기준으로 간주하였다. 결과: 피검자들은 영어와 중국어 문자 양쪽 모두에 대하여, 단초점 렌즈를 착용했을 때보다 누진렌즈를 착용했을 때 텍스트를 읽는데 더 오랜 시간이 걸렸다. 이러한 차이의 통계적 유의성은 영문자 'm'과 중문자 '一'의 경우에 관찰되었다. 결론: 실험 결과로부터, 중간 거리 영역의 좁은 시야로 인하여 누진렌즈의 착용이 가독성을 저하시킨다고 해석할 수 있다. 이러한 가독성의 저하는 청소년 학생들의 학습 능력을 저하시킬 수도 있다는 점을 감안하면, 학습기의 청소년에게 근시 억제를 위한 누진렌즈를 처방할 때 누진렌즈의 협소한 중간거리 시야가 독서 능력을 저하시킬 수 있다는 점을 고려하여 렌즈설계 디자인 등의 측면에서 주의를 기울일 필요가 있다.

본 연구는 두 종류의 표면 개질제 trimethylchlorosilane(TMCS), hexamethyldisilazane(HMDZ)를 사용하여 fumed silica의 표면 개질 과정에서 첨가량 변화에 따른 소수성 및 분산성 변화에 대한 연구를 진행하였다. 표면 개질 과정에서 사용된 개질제는 fumed silica 중량 대비 0~80wt%로 첨가하였으며, FT-IR(Fourier transform infrared spectroscopy), EA(Elemental analysis) 분석을 통해 개질제의 첨가량이 증가함에 따라 fumed silica의 소수성이 증가함을 확인하였다. 그리고 fumed silica의 소수성이 증가함에 따른 분산성 변화 분석을 위해 TEM(Transmission electron spectroscopy), PSA(Particle size analyzer)를 측정하였다. 그 결과, fumed silica의 소수성이 증가함에 따라 fumed silica의 입자간의 응집력이 약화되어 분산성이 향상되고 평균 입자 크기 또한 감소하는 것을 확인할 수 있었다. Fumed silica의 개질 안정성을 평가하기 위해 자체 실험을 진행한 결과, 소수성 개질된 fumed silica의 경우 표면 개질제 첨가량과 관계없이 일정 시간 이후에도 소수성이 유지되고 있음을 확인하였다.

This study focuses on evaluating the physico-chemical properties of extruded cassava starch added with corn flour. The raw materials were mixed at different ratios (corn flour/cassava starch 0:100, 25:75, 50:50, 75:25, 100:0 [w/w]), then extruded at different barrel temperatures (120 and 140°C) and moisture contents (20 and 25%), with the physicochemical and pasting properties of extrudates finally analyzed. The obtained results showed that the addition of corn flour to the mix resulted in an increase in specific length, lightness, yellowness, water absorption index, water solubility index, final viscosity, and setback viscosity of extrudates, while there was a decrease in redness and piece density. Other properties including the expansion ratio, reducing sugars, cold viscosity, peak viscosity, hold viscosity, and breakdown viscosity were more likely to be subjected to barrel temperature and moisture content. Mixing corn flour with cassava starch ameliorated the expansion properties, color, and some pasting properties of mixed extrudates. This study demonstrated that the use of corn flour and extrusion process with different barrel temperatures and moisture contents provided valuable data for the further development of extruded cassava starch.