• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.155-155
• /
• 2011

용융탄산염 연료전지(MCFC)는 $650^{\circ}C$에서 작동하는 고온형 연료전지 시스템이다. 이 시스템은 천연가스 등을 개질하여 생산된 수소를 바로 전기로 생산할 수 있는 시스템으로 열효율이 높으며, 현재 대체 발전시스템으로 각광을 받고 있다. MCFC는 개질방식에 따라 내부개질 방식과 외부개질 방식이 있다. 내부개질 방식은 수소를 생산하는 개질기가 스택내부에 장착된 형식으로 천연가스를 스택내부에서 개질하여 바로 전기를 생산하는 방식이다. 이 내부개질반응에 사용되는 촉매로는 알루미나에 고함량 (약 50 wt.%)으로 담지된 니켈(Ni) 계열촉매이 주로 쓰이고 있다. 이 고함량으로 담지된 촉매는 대부분 높은 활성을 보인다. 비교적 낮은 온도 운전조건 (약 $580{\sim}620^{\circ}C$)을 가지는 MCFC 내부개질에 적용하기 위해서는 활성점인 니켈을 최대한 담지체에 고르게 분산 시켜야한다. 이를 위해서 MgO를 이용하여 촉매의 활성점을 높게 분산시키는 연구를 진행 하였다. 촉매를 제조하는 방법으로 요소(urea)를 이용한 균일용액침전법을 이용하였다. 니켈함량은 50 wt.%로 고정을 한 다음, MgO 양과 $Al_2O_3$ 양을 각각 0 ~ 45 wt.%와 5 ~ 50 wt.%로 조절하면서 촉매를 제조하여 그 특성들을 분석하였다. 물성을 비교하기 위해서, X-선 회절분석 (XRD) 및 TPR, 물리화학흡착 실험을 하였다. 촉매의 활성을 살펴보기 위해서, fresh 상태 및 피독 상태에서 메탄수증기 개질활성 실험을 실시하였다. MgO 함량이 없거나 적은 촉매에서는 높은 BET surface area와 작은 NiO, metallic Ni 결정 크기가 나타났다. 반면 MgO 함량이 높은 촉매에서 낮은 BET surface area와 비교적 큰 NiO, metallic Ni 결정 크기가 나타났다. 또한 XRD 분석에서 MgO 함량이 증가할 수 록 MgO 결정 피크가 명확히 나타났으며, $MgAl_2O_4$ 피크는 나타나지 않았다. TPR 분석에서 촉매들의 환원 피크를 측정한 결과, 저함량의 MgO를 포함한 촉매는 $700^{\circ}C$ 부근에 환원 피크가 관찰되었고 MgO가 고함량인 촉매는 환원 피크가 $400^{\circ}C$ 부근에서 관찰되었다. 촉매의 초기 fresh 상태에서의 활성은 고함량 MgO를 포함한 Ni-90M10A 샘플을 제외하고 모든 촉매가 거의 비슷하게 나타났다. 그러나 $K_2CO_3$ 피독 상태에서는 MgO 함량이 증가할 수 록 활성이 좋지 않았음을 알 수 있었다. 따라서 MgO가 소량 포함된 촉매의 경우 fresh 상태에서는 우수한 물성과 활성을 보이지만, 피독상태에서는 MgO가 포함되지 않은 Ni-$Al_2O_3$ 촉매가 우수한 활성을 보였다.

• Toxicological Research
• /
• 제25권2호
• /
• pp.71-78
• /
• 2009

We investigated the pathogenesis of liver tissue damage during the lipid peroxidation and fibrogenesis with the observation of correlations between the parameters of collagen synthesis (and deposition) and lipid peroxidation in liver fibrosis (cirrhosis) rats. Rats were randomly divided into two groups, normal and $CCl_4$-thiopental sod. intoxicated group. And the one group was treated intragastrically with the mixture of $CCl_4$-thiopental sod. 3 times per week for 3 weeks. The liver tissue and sera were used for the measurement of hydroxyproline (HYP), malonedialdehyde (MDA) and superoxide dismutase (SOD). Biochemical parameters such as aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total-bilirubin and blood urea nitrogen (BUN) were measured. Additionally, the expression of collagen ${\alpha}1$(III) and $\beta$-actin mRNA was observed by RTPCR. The histological change in liver tissue was also observed by Masson's trichrome and H&E staining. Correlation analysis was carried by Spearman's rho method. All biochemical parameters except total-bilirubin were significantly higher in the $CCl_4$-thiopental sod. treated group than that of the normal group (p < 0.01). In the $CCl_4$-thiopental sod. treated group, Hyp as a parameter of collagen synthesis (deposition) and MDA as a metabolite of lipid peroxidation, were significantly elevated by 1.98 and 2.11 times higher than that of the normal group (p < 0.001) respectively. The activity of SOD in the $CCl_4$-thiopental sod. treated group is decreased significantly by 44.8% (p < 0.001). And collagen ${\alpha}1$(III) mRNA was more expressed in the $CCl_4$-thiopental sod. treated group than that of the normal group. However, the expression of $\beta$-actin mRNA is showed similar in both of groups. A good correlation was observed between the content of hyp and MDA concentration (r = 0.70, n = 40) in the two groups. And the correlation between the levels of hyp and SOD (r = -0.71, n = 25) is also reliable. However, no correlation were observed between MDA concentration and SOD (r = -0.40, n = 25) in the two groups. Elevated levels of MDA in $CCl_4$-thiopental sod. treated rats indicated enhancement of lipid peroxidation, which is accompanied by a decrease in SOD activity. Moreover, we could confirm that the parameters of collagen synthesis (and deposition) is in good correlation with the metabolite of lipid peroxidation (MDA) and the lipid peroxidation antagonizing enzyme (SOD). Hence, we propose that (1) lipid peroxidation and collagen synthesis (and deposition) could be enhanced by intragastrically application of $CCl_4$-thiopental sod. during a short terms. And (2) the intoxication of $CCl_4$-thiopental sod. could be used for monitoring of lipid peroxidation and collagen synthesis (and deposition) for test of antioxidant and antifibrotic agent.

• Journal of Animal Science and Technology
• /
• 제56권3호
• /
• pp.11.1-11.9
• /
• 2014

This study was conducted to evaluate the effects of dietary conjugated linoleic acid (CLA) on the performance of lactating sows and piglets as well as the immunity of piglets suckling from sows fed CLA. Eighteen multiparous Duroc sows with an average body weight (BW) of $232.0{\pm}6.38kg$ were randomly selected and assigned to two dietary treatments (n = 9 for each treatment), control (no CLA addition) and 1% CLA supplementation. For the control diet, CLA was replaced with soybean oil. Experimental diets were fed to sows during a 28-day lactation period. Litter size for each sow was standardized to nine piglets by cross-fostering within 24 hours after birth. Sow milk and blood samples were taken from sows and piglets after 21 and 27 days of lactation, respectively. Loss of BW was significantly (p < 0.05) higher in sows fed control diet compared to sows fed CLA diet. Piglet weights at weaning and weight gain during suckling were significantly (p < 0.05) higher in sows fed CLA compared to sows fed control diet. Serum non-esterified fatty acid (NEFA) and urea nitrogen concentrations were significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. IgG concentrations of the groups supplemented with CLA increased by 49% in sow serum (p < 0.0001), 23% in milk (p < 0.05), and 35% in piglet serum (p < 0.05) compared with the control group. Sows fed CLA showed an increase of 10% in milk yield compared with sows fed soybean oil (p < 0.05), even though there was no difference in daily feed intake between the treatments. Milk fat content was significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. Solid-not-fat yield was significantly (p < 0.05) higher in sows supplemented with CLA than in sows fed control diet and also protein-to-fat ratio in milk was significantly (p < 0.05) higher in sows fed CLA compared with the control group. The results show that CLA supplementation to sows increased milk yield without losing BW during lactation, whereas soybean oil supplementation resulted in severe BW loss.

• 성인간호학회지
• /
• 제12권1호
• /
• pp.88-98
• /
• 2000

Hemodialysis(HD)-associated hypotension is a frequent complication, but it is difficult to manage. Until now, several maneuvers have been tried to prevent the HD-associated hypotension. Of these, the sodium content of dialysate was regarded as an important factor for maintaining blood pressure during HD. In this study, we evaluated the effect of hypertonic dialysate on blood pressure, interdialytic weight gain and the incidence of thirst. The study was done for 6 weeks successively with 3 different groups. Each patient was dialysed with 3 different dialysates for 2 weeks: Group I(Conventional HD: sodium concentration: 137 mEq/L), Group II(Hypertonic HD: 147 mEq/L) and Group III (Sequential HD: from 147 to 140 mEq/L). Hemodynamic parameters(blood pressure, pulse rate and ultrafiltration rate), biochemical parameters(hematocrits, blood urea nitrogen, creatinine, osmolality, sodium, potassium, chloride, fasting blood sugar) and complications (interdialytic weight gain & thirsty sensation) were compared among 3 groups. The results were as follows: 1. Decline of systolic blood pressure and diastolic blood pressure at the time of a 3 hour check during hemodialysis was lower in the Group II than Group I and III (p=0.002; p=0.012). and decline of diastolic blood pressure at the time of a 4 hour check during hemodialysis was lower in the Group II and III than Group I (p=0.04). 2. Incidence of hypotensive episodes during dialysis was significantly lower in Group II than group I (p=0.0287). 3. The ultrafiltration in Group III at the time of 1 hour, 2 hour and 3 hour check during hemodialysis was higher than that in Group I and II at the time of 1 hour, 2 hour and 3 hour check during hemodialysis respectively (p=0.0001; p=0.0001; p=0.0004). 4. Interdialytic weight gain was higher in Group I($3.1{\pm}0.8$) than Group I($2.8{\pm}0.8$) and III ($2.9{\pm}0.9$) (p=0.0422). 5. Hematologic and biochemical results were not significantly different among 3 Groups. 6. Frequency of thirst was different in Group I, II and III, $0.05{\pm}0.12$, $0.41{\pm}0.24$and $0.22{\pm}0.29$ respectively (p=0.0259). The results suggest that hypertonic HD was effective in preventing HD-associated hypotension but interdialytic weight gain and thirst sensations were increased as compared with a conventional method. In this situation, sequential HD seems to be an alternative method to minimizes the side effect of hypertonic HD.

• 유기물자원화
• /
• 제22권4호
• /
• pp.45-53
• /
• 2014

본 연구는 SCB 저농도 액비에 질소, 인산, 칼리 성분을 첨가한 개량 SCB 액비(DSCB)의 시비에 따른 한국 잔디의 생육에 미치는 영향을 평가하기 위해 수행되었다. 처리구는 비료의 종류와 시비량에 따라 무처리구(NF), 화학비료를 시비한 대조구(CF), 유안으로 질소 성분을 보정한 DSCB를 80% 시비한 처리구 1(DSCB-A1), 유안으로 질소 성분을 보정한 DSCB를 100% 시비한 처리구 2(DSCB-A2), 요소로 질소 성분을 보정한 DSCB 처리구(DSCB-U) 그리고 대조구에 SCB를 시비한 처리구(CF+SCB)로 설정하여 엽색 지수, 엽록소 지수, 건물 중 및 잔디의 양분 함유량을 가지고 생육을 평가하였다. 엽색 지수와 엽록소 지수를 조사한 결과, NF보다 각각 1~3%와 14~28% 증가하였고, CF와 비교할 때, DSCB-A1, DSCB-A2 및 CF+SCB의 엽록소 지수는 약 7~12% 높게 조사되었다. 잔디 생육량은 DSCB-A1와 DSCB-A2에서 CF보다 25%와 19%씩 증가하였고, 질소 흡수량은 19%와 6%씩 증가하였다. DSCB-A1은 잔디 품질과 잔디생육 및 시비 효율이 가장 효과적인 처리구로 평가되었다. 이러한 결과들을 통해 한국 잔디에서 DSCB-Al의 시비는 화학비료보다 양질의 잔디품질을 보여 골프코스 관리에서 DSCB-A1의 활용은 화학비료를 대체할 수 있을 것으로 기대되었다.

• 생물환경조절학회지
• /
• 제15권4호
• /
• pp.377-384
• /
• 2006

오이묘가 저온피해를 입기 전, 후 토양수분조건과 몇 가지의 화학물질처리가 오이묘의 냉해 경감에 미치는 영향을 연구한 결과 토양수분 -0.3bar 적습상태에서 07:00시에 $2^{\circ}C$로 저온처리를 했을 때, 생존율은 28.3%이었으나 -5.5bar에서는 83.3%로 높아져 토양수분이 건조하면 저온피해가 감소되었다. 그러나 18:00시에 저온처리하면 -0.3bar에서도 생존율은 87% 이상이었다. 토양수분이 건조하면 엽신의 ABA함량은 크게 증가되었다. 저온처리 전, 후 ABA의 토양 및 엽면처리는 오이묘의 생존율을 유의하게 증가시켰고 세포의 전해질 누출량도 현저하게 감소시켰으며, 수량의 감소를 경감시켰다. 또한 ABA 처리는 저온처리 후보다는 저온처리 전에, 엽면처리보다는 토양에 처리하는 것이 보다 효과적이었다. ABA($10^{-5}M$)와 더불어 요소(0.2%)와 $KH_2PO_4$의 엽면살포는 오이의 생장과 수량에 미치는 저온피해를 경감시키는데 효과적이었다.

• 대한의생명과학회지
• /
• 제5권1호
• /
• pp.75-84
• /
• 1999

선천성 고혈압 흰쥐를 이용하여 puromycin Aminonucleoside (PAN)로 유도된 미세 변화신증에 대한 $\alpha$-tocopherol acetate의 효과를 알아보기 위하여, 정상군, PAN 투여군 (30 mg/kg), 비타민 E 투여군 (200 mg/kg) 그리고 PAN+비타민 E 투여 군으로 나누었다. 각 군은 약물 투여 후 2, 4, 8, 16일째 처치하여 혈청 생화학적 변화, 조직학적 변화, 그리고 미세구조적 변화를 관찰하였다. 실험동물의 체중은 PAN 투여군이 가장 낮은 증가율을 보였고, 비타민 E 투여군이 가장 높은 증가율을 보였다. 혈청 총단백질의 함량은 PAN투여 8일군에서 가장 낮았고, 혈중 요소성 질소와 크레아티닌의 함량은 P투여 8일군에서 가장 높게 나타났다. PAN+비타민 E 투여군에서는 PAN 투여군과 비교하여 혈청 총단백질의 함량이 증가되었고, 혈중 요소성 질소와 크레아티닌의 함량은 감소되었다. 조직학적 관찰 결과, 요세관 공간의 소실과 혈관사이세포의 증식이 PAN 투여 4일군에서 나타나기 시작하여, PAN투여 8일군에서 가장 현저하였으나 비타민 E 투여로 이러한 변화 정도는 감소되었다. PAS 염색 관찰 결과, 염색 정도가 PAN투여 8일군에서 가장 강하게 나타났고, 비타민 E 투여로 염색 정도는 감소되어 나타났다. 미세구조의 변화는 PAN투여 8일군에서 족돌기의 융합과 소실, 모세 혈관 내피세포의 공포화, 그리고 혈관사이세포와 사구체 기저막의 증식이 관찰되었고, 비타민 E투여로 감소되었다. 이러한 결과들로 보아 PAN으로 유도된 사구체 손상은 고혈압에 의해 가중될 수도 있으며, 사구체의 기능이상은 산화적 손상에 의한 것임을 간접적으로 시사하고 있다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권12호
• /
• pp.1763-1769
• /
• 2003

Two experiments were conducted to examine the production and quality of cassava hay and its utilization in diets for dairy cows. In experiment I, a $2{\times}2$ Factorial arrangement in a randomized complete block design with 4 replications was carried out to determine the effects of different initial (IC) and subsequent cutting (SC) on yield and composition of cassava plant. The results revealed that cassava could produce from 4 to 7 tonne of DM and 1.2 to 1.6 tonne of CP for the first six months after planting. CP content in cassava plant ranged from 20.8 to 28.5% and was affected by different SC regimes. Condensed tannin in cassava foliage ranged from 4.9 to 5.5%. Initial cutting at 2 months with subsequent cutting at 2 month intervals was the optimal to obtain high dry matter and protein yield. In the second experiment, five crossbred Holstein-Friesian cows in mid lactation with an initial live-weight of 505${\pm}6.1kg$ and average milk yield of 10.78${\pm}1.2kg/d$ were randomly assigned in a $5{\times}5$ Latin square design to study the effects of 2 levels of CH (1 and 2 kg/hd/d) and concentrate (1 to 2 kg of milk and 1 to 3 kg of milk) on milk yield and milk composition. The results showed that cassava hay increased rumen $NH_3-N$ and milk urea nitrogen (MUN) (p<0.05). Cassava hay tended to increase milk production and 4% FCM. Milk protein increased in cows fed cassava hay (p<0.05). Moreover, cassava hay could reduce concentrate levels in dairy rations thus resulting in increased economic returns. Cassava hay can be a good source of forage to reduce concentrate supplementation and improve milk quality.

• Asian-Australasian Journal of Animal Sciences
• /
• 제28권3호
• /
• pp.351-359
• /
• 2015

Twelve multiparous Holstein dairy cows in mid-lactation were selected for a replicated $4{\times}4$ Latin square design with a $2{\times}2$ factorial arrangement to investigate the effects of corn and soybean meal (SBM) types on rumen fermentation, N metabolism and lactation performance in dairy cows. Two types of corn (dry ground [DGC] and steam-flaked corn [SFC]) and two types of SBM (solvent-extracted and heat-treated SBM) with different ruminal degradation rates and extents were used to formulate four diets with the same basal ingredients. Each period lasted for 21 days, including 14 d for adaptation and 7 d for sample collection. Cows receiving SFC had a lower dry matter (DM) and total N intake than those fed DGC. However, the milk yield and milk protein yield were not influenced by the corn type, resulting in higher feed and N utilization efficiency in SFC-fed cows than those receiving DGC. Ruminal acetate concentrations was greater and total volatile fatty acids concentrations tended to be greater for cows receiving DGC relative to cows fed SFC, but milk fat content was not influenced by corn type. The SFC-fed cows had lower ruminal ammonia-N, less urea N in their blood and milk, and lower fecal N excretion than those on DGC. Compared with solvent-extracted SBM-fed cows, cows receiving heat-treated SBM had lower microbial protein yield in the rumen, but similar total tract apparent nutrient digestibility, N metabolism measurements, and productivity. Excessive supply of metabolizable protein in all diets may have caused the lack of difference in lactation performance between SBM types. Results of the present study indicated that increasing the energy degradability in the rumen could improve feed efficiency, and reduce environmental pollution.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권11호
• /
• pp.1546-1552
• /
• 2012

A feeding experiment with 40 lactating Holstein cows and 4 dietary treatments was conducted to investigate supplementation with different levels of alcohol fermented feed to the TMR on lactating performance, blood metabolites, milk fatty acid profile and cholesterol concentration of blood and milk. Forty Holstein lactating cows ($106{\pm}24$ d post-partum; mean${\pm}$SD) were distributed into four groups and randomly assigned to one of four treatments with each containing 10 cows per treatment. The treatment supplemented with TMR (DM basis) as the control (CON), and CON mixed with alcohol-fermented feeds (AFF) at a level of 5%, 10% and 15% of the TMR as T1, T2 and T3, respectively. Dry matter intake and milk yield were not affected by supplementation of AFF. An increased 4% FCM in the milk occurred in cows fed T3 diet compared with CON, while T1 and T2 diets decreased 4% FCM in a dose dependent manner. Supplementation of AFF increased the concentration of albumin, total protein (TP), ammonia, and high density lipoprotein-cholesterol in serum compared with CON. In contrast, supplementation with AFF clearly decreased concentration of blood urea nitrogen (BUN) and total cholesterol (TC) compare with CON. AFF supplementation increased the proportion of C18:1n9 and C18:2n6 compared to CON. A decrease in the concentration of saturated fatty acid (SFA) for T1, T2 and T3 resulted in an increased unsaturated fatty acid (USFA) to SFA ratio compared to CON. Concentration of cholesterol in milk fat was reduced in proportion to the supplemental level of AFF. Feeding a diet supplemented with a moderate level AFF to lactating cows could be a way to alter the feed efficiency and fatty acid profile of milk by increasing potentially human consumer healthy fatty acid without detrimental effects on feed intake and milk production. A substantially decreased cholesterol proportion in milk induced by supplementation AFF suggests that alcohol fermented feed may improve milk cholesterol levels without any negative effects in lactating cows.