• 한국재료학회지
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• 제10권1호
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• pp.15-20
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• 2000

기계적으로 합금처리한 Mg-18wt.%Ni 혼합물의 수소저장특성이 조사되었다. 1h, 3h, 그리고 6h 동안 기계적으로 합금처리한 혼합물들 중에서 6h동안 기계적으로 합금처리한 혼합물(MA 6h sample)이 가장 좋은 활성화, 수소화물 형성.분해 특성을 보인다. 수소화물 형성.분해 cycling을 시킴에 따라 $Mg_2$Ni상이 형성된다. MA 6h sample은 비교적 쉽게 활성화되며, 순수한 Mg나 Mg-10wt.%Ni 합금보다 수소화물 형성속도가 높으나, $Mg_2$Ni 합금보다는 수소화물 형성속도가 약간 낮다. MA 6h sample은 $Mg_2$Ni 합금에 비해 낮은 수소화물 분해속도를 보이지만, 순수한 Mg나 Mg-25wt.%Ni 합금보다는 높은 수소화물 분해속도를 보인다. MA 6h sample은 순수한 Mg나 다른 합금들보다 큰 수소저장용량을 가지고 있다.

• 대한금속재료학회지
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• 제50권12호
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• pp.949-953
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• 2012

$MgH_2$ was employed as a starting material instead of Mg in this work. A sample with a composition of 94 wt% $MgH_2-6$ wt% Ni (called $MgH_2-6Ni$) was prepared by reactive mechanical grinding. The hydriding and dehydriding properties were then examined. An $MgH_2-Ni$ hydrogen storage alloy that does not require an activation process was developed. The alloy was prepared in a planetary ball mill by grinding for 4 h at a ball disc revolution speed of 250 rpm under a hydrogen pressure of about 12 bar. The sample absorbed 3.74 wt% H for 5 min, 4.07 wt% H for 10 min, and 4.41 wt% H for 60 min at 573 K under 12 bar $H_2$, and desorbed 0.93 wt% H for 10 min, 1.99 wt% H for 30 min, and 3.16 wt% H for 60 min at 573 K under 1.0 bar $H_2$. $MgH_2-6Ni$ after reactive mechanical grinding contained ${\beta}-MgH_2$ (a room temperature form of $MgH_2$), Ni, ${\gamma}-MgH_2$ (a high pressure form of $MgH_2$), and a very small amount of MgO. Reactive mechanical grinding of Mg with Ni is considered to facilitate nucleation, and to reduce the particle size of Mg. $Mg_2Ni$ formed during reactive mechanical grinding also increases the hydriding and dehydriding rates of the sample.

• 한국재료학회지
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• 제23권5호
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• pp.266-270
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• 2013

The hydrogen storage properties of pure $MgH_2$ were studied and compared with those of pure Mg. At the first cycle, pure $MgH_2$ absorbed hydrogen very slowly at 573 K under 12 bar $H_2$. The activation of pure $MgH_2$ was completed after three hydriding-dehydriding cycles. At the $4^{th}$ cycle, the pure $MgH_2$ absorbed 1.55 wt% H for 5 min, 2.04 wt% H for 10 min, and 3.59 wt% H for 60 min, showing that the activated $MgH_2$ had a much higher initial hydriding rate and much larger $H_a$ (60 min), quantity of hydrogen absorbed for 60 min, than did activated pure Mg. The activated pure Mg, whose activation was completed after four hydriding-dehydriding cycles, absorbed 0.80 wt% H for 5 min, 1.25 wt% H for 10 min, and 2.34 wt% H for 60 min. The particle sizes of the $MgH_2$ were much smaller than those of the pure Mg before and after hydriding-dehydriding cycling. The pure Mg had larger hydrogen quantities absorbed at 573K under 12 bar $H_2$ for 60 min, $H_a$ (60 min), than did the pure $MgH_2$ from the number of cycles n = 1 to n = 3; however, the pure $MgH_2$ had larger $H_a$ (60 min) than did the pure Mg from n = 4 to n = 6.

• Clinical and Experimental Reproductive Medicine
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• 제15권2호
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• pp.135-147
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• 1988

To compare the stimulation effect of the ratio in follicle stimulating hormone and luteinizing hormone in induction of multiple follicular growth, the serum $E_2$ level, the diameter of follicle, number of aspirated follicles and cleavage rate of in vitro fertilized preovulatory oocytes as well as the pregnancy rate were evaluated. Forty one patients with irreparable tubal disease were stimulated by hMG(n=24) or FSH/hMG(n=17) for the purpose of in vitro fertilization and embryo transfer. The following results were obtained. 1. Serum estradiol($E_2$) levels on the day of hCG administration were $921.0{\pm}353.3\;pg/ml$ in hMG group and $1272.9{\pm}1060.6\;pg/ml$ in FSH/hMG group. The serum $E_2$ value of hMG group was significantly lower than that of FSH/hMG group. 2. The diameter of leading follicle by ultrasonogram on the day of hCG administration were $16.2{\pm}2.0\;mm$ in hMG group and $16.2{\pm}2.6\;mm$ in FSH/hMG group. No significant difference of follicle diameter between two groups was demonstrated. 3. The number of follicles with diameter above 10 mm by sonogram on the day of hCG injection were $3.91{\pm}2.32$ in hMG group and $6.52{\pm}3.86$ in FSH/hMG group. There was significant difference of number of follicles between two groups, (p< 0.01). 4. The number of oocytes found per patient at aspiration were $2.59{\pm}1.00$ in hMG group and 3. $76{\pm}2.31$ in FSH/hMG group. There was significant difference of number of aspirated oocytes between two groups. (p< 0.05). 5. The detection rate of preovulatory oocyte at aspiration were 68.4%(39/57) in hMG group (n=22) and 77.6%(38/49) in FSH/hMG group (n=13). 6. The cleavage rate of preovulatory oocyte at 44 hours after insemination were 74.4%(29/39) in hMG group(n=22) and 81.6%(31/38) in FSH/hMG group (n=13). When only hMG was used, one pregnancy was established in 15 patients to whom 29 zygotes were transferred. And a full term normal female baby was delivered by elective cesarean section. In the FSH/hMG group, five pregnancies out of 9 transferred patients were confirmed by serum ${\beta}-hCG$. Two pregnancies were spontaneously aborted before the 6th week of pregnancy. One patient aborted her baby at the 18th week of pregnancy because of incompetent internal os of the cervix. Two patients delivered two full term babies by elective cesarean section. From the above findings, paralell with the increase in the ratio of exogenous follicle stimulating hormone to luteinizing hormone, an increase in oocyte recovery was observed as well as an improvements in pregnancy rate. It was concluded that FSH enrichment early in the follicular phase had a beneficial effect in the controlled ovarian hyperstimulation.

• 한국재료학회지
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• 제24권3호
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• pp.129-134
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• 2014

Pure $MgH_2$ was milled under a hydrogen atmosphere (reactive mechanical grinding, RMG). The hydrogen storage properties of the prepared samples were studied at a relatively low temperature of 423 K and were compared with those of pure Mg. The hydriding rate of the Mg was extremely low (0.0008 wt% H/min at n = 4), and the $MgH_2$ after RMG had higher hydriding rates than that of Mg at 423 K under 12 bar $H_2$. The initial hydriding rate of $MgH_2$ after RMG at 423 K under 12 bar $H_2$ was the highest (0.08 wt% H/min) at n = 2. At n = 2, the $MgH_2$ after RMG absorbed 0.39 wt% H for 5 min, and 1.21 wt% H for 60 min at 423K under 12 bar $H_2$. At 573 K under 12 bar $H_2$, the $MgH_2$ after RMG absorbed 4.86 wt% H for 5 min, and 5.52 wt% H for 60 min at n = 2. At 573 K and 423 K under 1.0 bar $H_2$, the $MgH_2$ after RMG and the Mg did not release hydrogen. The decrease in particle size and creation of defects by reactive mechanical grinding are believed to have led to the increase in the hydriding rate of the $MgH_2$ after RMG at a relatively low temperature of 423 K.

• 한국잠사곤충학회지
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• 제17권2호
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• pp.161-170
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• 1975

This study is to investigate the content of crude protein intruded in the sericin of cocoon shell and pupa by treatment of buffer solution (pH 1 to pH 13) 20 ml per 1 gram for 30 and 60 minutes at 30$^{\circ}C$, 60$^{\circ}C$ and 100${\pm}$2$^{\circ}C$, respectively. The results obtained are summarized as follows. 1. The quantity of total crude protein obtained from cocoon shell and pupa by treatment during 30 minutes at 30$^{\circ}C$ was dissolved as the largest quantity of 11.874 mg/g at pH 1 and l5.93mg/g at pH 13, but dissolved the smallest quantity 1.75g/g at pH 5 as known. and tile quantity of crude protein treated for 60 minutes is 13.437mg/g at pH 1 and 22.50mg/g at pH 13. Also, the smallest quantity is 2. 813mg/g at pH 5 as known. 2. By the treatment during 30 minutes at 60$^{\circ}C$, the dissolved largest quantity was 13.12mg/g at pH 1 and 21.875 mg/g at pH 13, but the smallest quantity is 2.375mg/g at pH 5 as known After treatment for 60 minutes at 60$^{\circ}C$, the dissolved largest quantity was 17.500 mg/g at pH 1 and 31.56mg/g at pH 13, bu the smallest quantity is 3.849 mg/g at pH 5. 3. The dissolved crude protein from the cocoon shell and pupa by treatment for 30 minutes at 100${\pm}$2$^{\circ}C$ was the largest quantity of 147.000mg/g at pH 1 and 398. 125mg/g at pH 13, but the smallest quantity is 75.00mg/g at pH 5 as known. After treatment for 60 minutes at 100${\pm}$2$^{\circ}C$, the largest quantity was 253.76 mg/g at pH 1 and 460.625mg/g at pH 13, but the smallest quantity is 139.375mg/g at pH 5 as known. 4. The dissolved crude protein from the cocoon shell and pupa was not different in quantity by treatment at 30$^{\circ}C$ or 60$^{\circ}C$. But dissolved crude protein was large quantity from cocoon shell more than pupa, as known. 5. The treatment of cocoon shell and pupa during 60 minutes at 100${\pm}$20$^{\circ}C$ was increased to the dissolved largest quantity of crude protein of 19.20％ at pH 1 and 22. 18％ at pH 13 from the cocoon shell and 6. 12％ at pH, an d 23.87％ at pH 13 from the pupa. But dissolved crude protein was increased to the larger quantity from pupa more than cocoon shell.

• 한국재료학회지
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• 제23권10호
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• pp.562-567
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• 2013

A 90 wt% Mg-10 wt% $NbF_5$ sample was prepared by mechanical milling under $H_2$ (reactive mechanical grinding). Its hydriding and dehydriding properties were then examined. Activation of the 90 wt% Mg-10 wt% $NbF_5$ sample was not required. At n=1, the sample absorbed 3.11 wt% H for 2.5 min, 3.55 wt% H for 5 min, 3.86 wt% H for 10 min, and 4.23 wt% H for 30 min at 593K under 12 bar $H_2$. At n=1, the sample desorbed 0.17 wt% H for 5 min, 0.74 wt% H for 10 min, 2.03 wt% H for 30 min, and 2.81 wt% H for 60 min at 593K under 1.0 bar $H_2$. The XRD pattern of the 90 wt% Mg-10 wt% $NbF_5$ after reactive mechanical grinding showed Mg, ${\beta}-MgH_2$ and small amounts of ${\gamma}-MgH_2$, $NbH_2$, $MgF_2$ and $NbF_3$. The XRD pattern of the 90 wt% Mg-10 wt% $NbF_5$ dehydrided at n=3 revealed Mg, ${\beta}-MgH_2$, a small amount of MgO and very small amounts of $MgH_2$ and $NbH_2$. The 90 wt% Mg-10 wt% $NbF_5$ had a higher initial hydriding rate and a larger quantity of hydrogen absorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% $Fe_2O_3$, which were reported to have quite high hydriding rates and/or dehydriding rates. The 90 wt% Mg-10 wt% $NbF_5$ had a higher initial dehydriding rate (after an incubation period) and a larger quantity of hydrogen desorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% $Fe_2O_3$.

• 대한금속재료학회지
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• 제50권2호
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• pp.183-190
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• 2012

Hydrogen was generated by the reaction of metal hydride with water. The variation of hydrogen generation with the kind of powders (milled $MgH_2$, and $MgH_2$ milled with various contents of MgO, $MgCl_2$ or $Ni+Nb_2O_5$) was investigated. $MgH_2$ powder with a hydrogen content of 6.05 wt% from Aldrich Company was used. Hydrogen is generated by the reaction of Mg as well as $MgH_2$ with water, resulting in the formation of byproduct $Mg(OH)_2$. For about 5 min of reaction time, milled $95%MgH_2+5%MgO$ has the highest hydrogen generation rate among milled $MgH_2+x%MgO$ (x=0, 5, 10, 15 and 20) samples. Milled $90%MgH_2+10%MgCl_2$ has the highest hydrogen generation rate among all the samples.

• 한국식품영양과학회지
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• 제33권7호
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• pp.1119-1125
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• 2004

콩 식이섬유로부터 제조한 헤미셀룰로즈가 streptozotocin으로 유발한 당뇨쥐의 혈당과 혈청콜레스테롤함량에 미치는 영향을 조사하였다. 실험군은 셀룰로즈군(대조군), 헤미셀룰로즈 0.5% 식이군(H-1군), 헤미셀룰로즈 1% 식이군(H-2군)으로 나누어 6주간 사육한 후 당뇨를 유발시키고 계속해서 1주간 사육하였다. 당뇨유발에 따른 식이섭취량과 체중증가량 및 식이효율은 H-2식이군이 대조군과 H-1군에서 보다 높은 값을 나타낸 반면 음용수 섭취량은 H-2군에서 낮았다. 간장의 무게는 H-2군이 대조군과 H-1군에 비하여 유의적으로 낮았다. 혈당은 대조군에서는 212.8 mg/dL, H-1 군에서는 160.5 mg/dL, H-2군에서 는 141.0 mg/dL으로 H-2군은 대조군의 66%수준이었으며 뇨당은 대조군 0.97 mg/dL, H-1군 0.53 mg/dL, H-2군 0.35 mg/dL로 H-1군은 대조군의 55%, H-2군은 대조군의 36%로 헤미셀룰로즈 식 이군이 대조군에 비하여 유의적으로 낮았다. 혈청내 중성지질의 함량은 식이에 따른 유의적 인 차이는 보이지 않았으나 혈청 총콜레스테롤 함량은 대조군에서 101.6 mg/dL, 식이군에서는 73.8∼78.4 mgidL로 유의적으로 낮았으며, 혈청 HDL-콜레스테롤 함량은 모든 실험군에서 39.8∼44.7 mg/dL 범위로 비슷한 수치를 나타내었다. HTR과 동맥경화지수는 대조군에서는 각각 0.44 및 1.27로 나타났으나 헤미셀룰로즈 식이군에서는 각각 0.54 및 0.46∼0.85로 대조군보다 낮았다. 이상의 결과, 콩 식이섬유로부터 추출한 헤미셀룰로즈는 항당뇨효과가 높음을 나타내었다.

• 한국환경과학회지
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• 제5권5호
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• pp.611-617
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• 1996

유일한 탄소원으로서 Biphenyl을 포함하고 있는 액체배지에서 Pseudomonas sp. P2의 생육에 미치는 영양원의 효과에 관해 연구하였다. Pseudomonas sp. P2의 특성을 조사하기 위한, 배양시간은 균의 생육 유선에서 대수성장기 말인 100시간으로 하였다. PCBs를 분해하는 Pseudomonas sp. P2의 생육을 위한 최적 조성은 1000 mg/L $NH_4NO_3$, 1000 mg/L KH_2PO_4$, 100 mg/L MgSO_4$.$7H_2O$, 30 mg/L $CaCl_2$.$2H_2O$, 200 mg/L NaCl, 10mg/L $FeSO_4$.$7H_2O$였다. Pseudomonas sp. P2에 의한 100시간 배양후 절연유 내에 있는 PCBs의 분해률은 500mg/L에서 59.3%, 1000mg/L에서 57.6%, 1500mg/L에서 51.4%, 2000mg/L에서는 48.775 였다.