• Asian-Australasian Journal of Animal Sciences
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• 제29권9호
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• pp.1294-1299
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• 2016

An experiment was conducted to investigate the effect of peripheral insulin treatment on appetite in chicks. Six-d-age chicks with ad libitum feeding or fasting for 3 h before injection received a subcutaneous injection of 0, 1, 3, 5, 10, or 20 IU of insulin or vehicle (saline). The results showed peripheral insulin treatment (1 to 20 IU) did not alter significantly the feed intake in chicks under either ad libitum feeding or fasting conditions within 4 h (p>0.05). Compared with the control, plasma glucose concentration was significantly decreased after insulin treatment of 3, 5, 10, and 20 IU for 4 h in chicks with ad libitum feeding (p<0.05). In fasted chicks, 10 and 20 IU insulin treatments significantly decreased the plasma glucose level for 4 h (p<0.05). Peripheral insulin treatment of 10 IU for 2 or 4 h did not significantly affect the hypothalamic genes expression of neuropeptide Y, proopiomelanocortin, corticotropin-releasing factor and insulin receptors (p>0.05). All results suggest peripheral administration of insulin has no effect on appetite in chicks.

• Journal of Nutrition and Health
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• 제31권9호
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• pp.1377-1384
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• 1998

본 연구에서는 streptozotocin으로 당뇨를 유발시킨 횐쥐에게 methanol로 추출하여 분획한 참마의 $H_2O$ 분획물을 경구투여하고 selenium은 식이로 보충하여 당뇨시 14일간 혈당과 지질대사에 미치는 영향을 실험하여 다음과 같은 결과를 얻었다. 당뇨대조군은 당뇨로 인한 대사상의 변화로 정상군과는 다른 대사적인 차이를 나타내었다. 전 실험 기간 중 횐쥐의 체중변화는 정상군에 비해 당뇨실험군 모두에서 유의적으로 감소되었으며 DJT-Se군에서 다른 당뇨실험군보다 적은 양의 체중감소를 보였다. 참마와 Se 보충식이에 따른 식이효율도 DJT-Se군에서 유의적인 차이는 아니었지만 다른 당뇨실험군에 비해 높았다. 장기 의 무게를 체중 100g당으로 환산하였을 때 간장과 신장의 무게는 정상군보다 유의적으로 비대해졌으며 비장은 당뇨실험군 모두에서 정상군보다 무게가 낮게, 췌장은 높게 나타났다. 혈장 포도당 수준은 당뇨실험군 중 DJT-Se군에서 유의적으로 낮아졌으며 인슐린의 함량 수준은 당뇨실험군 간의 유의적인 차이를 보이지 않았으나 DJT-Se군에서 약간 높았다. 혈장단백질 수준은 당뇨대조군에 비해 당뇨실험군 모두에서 높게 나타났다. 혈장 지질 수준에 미치는 영향을 보면 혈장 cholesterol의 경우 당뇨대조군과 당뇨실험군 간의 큰 차이는 없었으나 당뇨실험군에서 낮은 경향을 보였다. HDL-cholesterol 수준은 모든 당뇨실험군에서 높게 나타났다. 중성지방의 경우는 DJT-Se군과 Se군에서 유의적으로 낮은 수준이었다. 유리지방산 함량은 정상군과 당뇨실험군 사이에 차이를 보이지 않았다. AST와 ALT 활성도는 군 간에 큰 차이를 보이지 않았으나 당뇨대조 군에 비해 DJT군에서는 유의성을 보였다. 본 연구 결과 참마나 Se를 독립적으로 섭취하는 것 보다는 병용하여 보충하는 것이 항산화 작용의 상승효과를 보여주어 고혈당과 지방대사산물에 작용하여 혈당강하효과를 보일 것으로 생각된다. 참마의 혈당강하에 영향하는 생리활성성분과 Se보충에 의한 대사적인 변화에 대하여 더 구체적인 생화학적인 연구가 이루어져야 될 것으로 여겨진다.

• 한국표면공학회지
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• 제52권4호
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• pp.194-202
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• 2019

A systematic investigation was made on the influence of processing parameters such as gas composition and treatment temperature on the surface characteristics of hardened layers of low temperature plasma nitrided 316L Austenitic Stainless Steel. Various nitriding processes were conducted by changing temperature ($370^{\circ}C$ to $430^{\circ}C$) and changing $N_2$ percentage (10% to 25%) for 15 hours in the glow discharge environment of a gas mixture of $N_2$ and $H_2$ in a plasma nitriding system. In this process a constant pressure of 4 Torr was maintained. Increasing nitriding temperature from $370^{\circ}C$ to $430^{\circ}C$, increases the thickness of S phase layer and the surface hardness, and also makes an improvement in corrosion resistance, irrespective of nitrogen percent. On the other hand, increasing nitrogen percent from 10% to 25% at $430^{\circ}C$ decreases corrosion resistance although it increases the surface hardness and the thickness of S phase layer. Therefore, optimized condition was selected as nitriding temperature of $430^{\circ}C$ with 10% nitrogen, as at this condition, the treated sample showed better corrosion resistance. Moreover to further increase the thickness of S phase layer and surface hardness without compromising the corrosion behavior, further research was conducted by fixing the $N_2$ content at 10% with introducing various amount of $CH_4$ content from 0% to 5% in the nitriding atmosphere. The best treatment condition was determined as 10% $N_2$ and 5% $CH_4$ content at $430^{\circ}C$, where the thickness of S phase layer of about $17{\mu}m$ and a surface hardness of $980HV_{0.1}$ were obtained (before treatment $250HV_{0.1}$ hardness). This specimen also showed much higher pitting potential, i.e. better corrosion resistance, than specimens treated at different process conditions and the untreated one.

• 마이크로전자및패키징학회지
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• 제28권4호
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• pp.109-114
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• 2021

상압 수소 플라즈마 전처리가 구리-구리 직접 본딩에 미치는 영향에 대해서 조사하였다. 상압 수소 플라즈마 처리를 통해 구리 박막의 표면 산화층을 환원시킬 수 있었음을 GIXRD 분석을 통해 확인하였다. 플라즈마 파워가 크고 플라즈마 처리 시간이 길수록 환원력 및 표면 거칠기 관점에서 효과적이었다. DCB를 이용한 계면 결합 에너지 측정에서 상압 수소 플라즈마 전처리 후 300℃에서 본딩한 경우 양호한 계면 결합 에너지를 나타내었으나, 본딩 온도가 낮아질수록 계면 결합 에너지가 낮아져 200℃에서는 본딩이 이루어지지 않았다. 습식 전처리의 경우 250℃ 이상에서 본딩한 경우 강한 결합력을 보였으며, 200℃에서는 낮은 계면 결합 에너지를 나타내었다.

• 열처리공학회지
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• 제8권4호
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• pp.255-265
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• 1995

Stainless steel type 304L has been nitrided in the low pressure (600Pa) and high nitrogen (80% $N_2$+20% $H_2$) environment for 5 hours by the square-wave-pulsed-d.c. plasma as a function of temperature $400{\sim}550^{\circ}C$ and pulsation. At the lower temperature range of $400{\sim}500^{\circ}C$ and at the relatively high ratio of pulse duration to pulse period. "S-phase" has been developed in the form of thin nitrided surface layer which has many cracks, leading to be nearly impossible for the industrial anti-wear and anti-corrosion applications. At the higher temperature up to $550^{\circ}C$ with the increasing ratio of the pulse duration to pulse period up to $50{\mu}s/100{\mu}s$, the nitrided layer, whose growth rate has increased also, has been composed mainly of CrN and $Fe_4N$ phases and has become thick, uniform and nearly crack-free.

• 한국분말재료학회지
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• 제30권6호
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• pp.470-477
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• 2023

The effects of annealing on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Si alloys fabricated by high-energy ball milling (HEBM) and spark plasma sintering (SPS) were investigated. The HEBM-free sintered alloy primarily contained Mg₂Si, Q-AlCuMgSi, and Si phases. Meanwhile, the HEBM-sintered alloy contains Mg-free Si and θ-Al₂Cu phases due to the formation of MgO, which causes Mg depletion in the Al matrix. Annealing without and with HEBM at 500℃ causes partial dissolution and coarsening of the Q-AlCuMgSi and Mg₂Si phases in the alloy and dissolution of the θ-Al₂Cu phase in the alloy, respectively. In both alloys, a thermally stable α-AlFeSi phase was formed after long-term heat treatment. The grain size of the sintered alloys with and without HEBM increased from 0.5 to 1.0 ㎛ and from 2.9 to 6.3 ㎛, respectively. The hardness of the sintered alloy increases after annealing for 1 h but decreases significantly after 24 h of annealing. Extending the annealing time to 168 h improved the hardness of the alloy without HEBM but had little effect on the alloy with HEBM. The relationship between the microstructural factors and the hardness of the sintered and annealed alloys is discussed.

• 열처리공학회지
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• 제14권1호
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• pp.8-16
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• 2001

The effects of gas composition, pressure, temperature and time on the case thickness, hardness and nitride formation in the surface of tool steels(STD11 and STD61) have been studied by micro-pulse plasma nitriding. External compound layer and internal diffusion layer and the diffusion layer were observed in the nitrided case of tool steels. The relative amounts and kind of phases formed in the nitrided case changed with the change of nitriding conditions. Generally, only nitride phases such as ${\gamma}(Fe_4N)$, ${\varepsilon}(Fe_{2-3}N)$, or $Cr_{1.75}V_{0.25}N_2$ phases were detected in the compound layer, while nitride and carbide phases such as ${\varepsilon}-nitride(Fe_{2-3}N)$, $(Cr,Fe)_{\gamma}C_3$ or $Fe_3C$ were detected in the diffusion layer by XRD analysis. The thickness of compound layer increased with the increase of nitrogen content in the gas composition. Maximum case depth was obtained at gas pressure of 200Pa.

• 한국재료학회지
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• 제11권9호
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• pp.802-809
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• 2001

Electroplating is an attractive alternative deposition method for copper with the need for a conformal and conductive seed layer In addition, the Cu seed layer should be highly pure so as not to compromise the effective resistivity of the filled copper interconnect structure. This seed layer requires low electrical resistivity, low levels of impurities, smooth interface, good adhesion to the barrier metal and low thickness concurrent with coherence for ensuring void-free fill. The electrical conductivity of the surface plays an important role in formation of initial Cu nuclei, Cu nucleation is much easier on the substrate with higher electrical conductivities. It is also known that the nucleation processes of Cu are very sensitive to surface condition. In this study, copper seed layers deposited by magnetron sputtering onto a tantalum nitride barrier layer were used for electroplating copper in the forward pulsed mode. Prior to electroplating a copper film, the Cu seed layer was cleaned by plasma H$_2$ and $N_2$. In the plasma treatment exposure tome was varied from 1 to 20 min and plasma power from 20 to 140W. Effects of plasma pretreatment to Cu seed/Tantalum nitride (TaN)/borophosphosilicate glass (BPSG) samples on electroplating of copper (Cu) films were investigated.

• 한국환경과학회지
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• 제21권4호
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• pp.479-488
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• 2012

A Dielectric barrier discharge (DBD) plasma is shown in the present investigation to be effective of phenol degradation in the aqueous solutions in batch reactor with continuous air bubbling. Removal of phenol and effects of various parameters on the removal efficiency in the aqueous solution with high-voltage streamer discharge plasma are studied. The effect of 1st voltage (80 ~ 220 V), air flow rate (3 ~ 7 L/min), pH (3 ~ 11), electric conductivity of solution (4.16 ${\mu}S$/cm, deionized water) ~ 16.57 mS/cm (addition of NaCl 10 g/L) and initial phenol concentration (2.5 ~ 20.0 mg/L) were investigated. The observed results showed that phenol degradation was higher in the basic solution than that of the acidic. The optimum values on the 1st voltage and air flow rate for phenol degradation were 140 V and 6 L/min, respectively. It was considered that absorbance variation of $UV_{254}$ of phenol solution can be use as an indirect indicator of change of the non-biodegradable organic compounds within the treated phenol solution. Electric conductivity was not influenced the phenol degradation. To obtain the removal efficiency of phenol and COD of phenol over 97 % (initial phenol concentration, 10.0 mg/L), 80 min and 120 min were need, respectively. Phenol and COD degradation showed a pseudo-first order kinetics.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2003년도 제25회 학술발표회 초록집
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• pp.69-69
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• 2003