• Title/Summary/Keyword: $MgB_4$

Search Result 3,590, Processing Time 0.033 seconds

A Study on the Constituents of the Pollen of Pinus densiflora Siebol et Zuccarini and Pinus rigida Miller -Proximate Composition, Mineral, Heavy Metal, Vitamin and Free Sugar Contents- (적송화분과 리기다송화분의 성분 조성에 관한 연구 -일반성분, 무기질, 중금속, 비타민, 유리당의 함량-)

  • 김혜자
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.21 no.2
    • /
    • pp.201-206
    • /
    • 1992
  • Pinus pollen is used as the chief ingredient for Song-wha-dashik (Korea's traditional pattern-pressed candy). It has been the food stuff indispensable especially on the occasion of performing ancestral rites and holding a banquet since Shilla and Koryo Dynasty. In this paper, therefore, a new examination is made of the nutritive ingredients of the very Pinus pollen. Analysis has been made of the proximate composition, minerals, heavy metals, vitamins and free sugars of the Pollen of both Pinus densinora Siebol et Zuccarini and Pinus rigida Miller. In the proximate composition, Pinus rigida Miller is high except in free sugar ; crude ash (4.0%), crude protein (15.0%), crude fat (2.5%), crude fiber (17.5%). A lot of minerals have been found in both the samples. They contain Mg, Cl, Ca, Fe, Mn, Na, Zn, etc. In heavy metals, both the samples contain the same quantity of Cd(0.3 ppm) and the contents of Pb, Cu, and As are lower than the maximal limit permitted for food stuff. The contents of vitamin B$_1$, B$_2$, vitamin C are a little higher in Pinus rigida Miller : in vitamin E, on the contrary, Pinus densiflora Siebol et Zucarini (1.6 mg) doubles Pinus rigida Miller (0.8 mg). In free sugars, the results is as follows : 6.6%/6.9% in sucrose : 0.2% in fructose : 2.1% /2.9% in glucose respectively.

  • PDF

Changes of Saponin during the Cultivation of Soybean Sprout (콩나물 생장 중 사포닌의 변화)

  • Oh, Bong-Yun;Park, Bock-Hee;Ham, Kyung-Sik
    • Korean Journal of Food Science and Technology
    • /
    • v.35 no.6
    • /
    • pp.1039-1044
    • /
    • 2003
  • We investigated the changes in saponins during the cultivation of soybean sprout. Crude saponin content was 4.15mg/g in germinated soybean and reached its peark (5.33mg/g) in soybean sprout cultivated for six days. Saponin content in the cotyledon, stem, and root of the soybean sprout cultivated for six days were 4.17, 7.46, and 7.45mg/g, respectively. Soyasaponins extracted from the soybean sprout were analyzed with LC-electrospray ionization (ESI)-mass spectrometry, in which a reverse phase $C_18$ column was used for separation of saponins. In the soybeen sprout, group B saponin, I, II, III, IV, and V increased 7, 2, 1.4, 8.7, and 3.3 fold, respectively, compared to those in the soybean seed. Group B saponin I, II, III, IV, and V in the stem of the soybean sprout were 10.53, 1.45, 10.49, 5.72 and 8.14 fold the level of those in the cotyldon, respectively. In the root, the contents of group B saponin I, III, IV, and V were 5.54, 2.77, 4.86 and 9.73 fold, respectively, higher than those in cotyledon, but the content of group B saponin 2 was 2.96 fold less than that in cotyledon. These results indicate that the biosyntheses of group B saponins are differentially regulated in growing soybean sprout.

Mechanistic Aspects in the Grignard Coupling Reaction of Bis(chloromethyl)dimethylsilane with Trimethylchlorosilane

  • 조연석;유복렬;안삼영;정일남
    • Bulletin of the Korean Chemical Society
    • /
    • v.20 no.4
    • /
    • pp.422-426
    • /
    • 1999
  • The Grignard reactions of bis(chloromethyl)dimethylsilane (1) with trimethylchlorosilane (2) in THF give both the intermolecular C-Si coupling and intramolecular C-C coupling products. At beginning stage, 1 reacts with Mg to give the mono-Grignard reagent ClCH2Me2SiCH2MgCl (1) which undergoes the C-Si coupling reaction to give MC2Si(CH2SiMe3)2 3, or C-C coupling to a mixture of formula Me3SiCH2(SiMe2CH2CH2)nR1 (n = 1, 2, 3, ..; 4a, R1I = H: 4b, R1 = SiMe3). In the reaction, two reaction pathways are involved: a) Ⅰ reacts with 2 to give Me3SiCH2SiMe2CH2Cl 6 which further reacts with Mg to afford a Me2SiCH2Mel-SiCH2MgCl (Ⅱ) or b) I cyclizes intramolecularly to a silacyclopropane intermediate A, which undergoes a ring-opening polymerization by the nucleophilic attack of the intermediates I or Ⅱ, followed by the termination reaction with H2O and 2, to give 4a and 4b, respectively. As the mole ratio of 2/1 increased from 2 to 16 folds, the formation of product 3 increased from 16% to 47% while the formation of polymeric products 4 was reduced from 60% to 40%. The intermolecular C-Si coupling reaction of the pathway a becomes more favorable than the intramolecular C-C coupling reaction of the pathways b at the higher mole ratio of 2/1.

The Growth and Optical Properties of $MgGa_2Se_4$ Single Crystal ($MgGa_2Se_4$ 단결정의 성장과 광학적 특성)

  • 김형곤;이광석;이기형
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.25 no.4
    • /
    • pp.402-406
    • /
    • 1988
  • The MgGa2Se4 single crystal for study of optical properties is for the first time grown by Bridgmna method. The crystal structure of grown MgGa2Se4 single crystal has the Rhomobohedral structure (R3m) and its lattice constant are a=3.950\ulcorner c=38.893\ulcornerin Hexagonal structure. The energy band structure of grown MgGa2Se4 single crystal structure has direct band gap and the optical energy gap measured from optical absorption in this crystal is 2.20eV at 290K. The temperature dependence of energy gap was given Eg(T)=Eg(O)-aT\ulcorner)B+T), from varshni equation, where Eg(O)=2.34eV, a=8.79x10**-4eV/and b=250K.

  • PDF

Magnesium diboride(MgB2) wires for applications

  • Patel, Dipak;Kim, Jung Ho
    • Progress in Superconductivity and Cryogenics
    • /
    • v.18 no.1
    • /
    • pp.1-5
    • /
    • 2016
  • Field and temperature dependence of the critical current density, Jc, were measured for both un-doped and carbon doped $MgB_2/Nb/Monel$ wires manufactured by Hyper Tech Research, Inc. In particular, carbon incorporation into the $MgB_2$ structure using malic acid additive and a chemical solution method can be advantageous because of the highly uniform mixing between the carbon and boron powders. At 4.2 K and 10 T, Jc was estimated to be $25,000-25,300Acm^{-2}$ for the wire sintered at $600^{\circ}C$ for 4 hours. The irreversibility field, $B_{irr}$, of the malic acid doped wire was approximately 21.0 - 21.8 T, as obtained from a linear extrapolation of the J-B characteristic. Interestingly enough, the Jc of the malic acid doped sample exceeds $10^5Acm^{-2}$ at 6 T and 4.2 K, which is comparable to that of commercial Nb-Ti wires.

Chemical Components and Pulverization Conditions of the Pollens of Pinus densiflora S. et Z. and Pinus thunbergii Parl (소나무와 해송 화분의 화학적 성분과 파쇄 조건에 관한 연구)

  • 김계환;오혁근;윤계순;박준모;최태기
    • Journal of Korea Foresty Energy
    • /
    • v.18 no.2
    • /
    • pp.47-54
    • /
    • 1999
  • This study was to analyze the chemical components of the pollens of Pinus densiflora S. et Z. and P. thunbergii Parl. and to investigate the optimal conditions for pollen pulverization. The results were as follow : (1) The contents of moisture, crude ash, crude protein, crude fat, crude filber and carbohydrate in the pollen of P. densiflora were 9.8%, 2.3%, 11.9%, 2.9%, 7.7%, and 65.4%, respectively, while those of P. thunbergii were 10.5%, 2.2%, 13.5%, 3.5%, 8.5% and 61.8%, respectively. All the contents of P. densiflora and P.thunbergii were much higher than those general crop grains. (2) The pollen of Pinus densiflora and P. thunbergii eighteen different amino acids were detected in. Among them, ten esssential amino acids were identified, which showed high nutrition values. (3) The contents of vitamins A, B1, B2, C and E in the pollen of P. densiflora were 7.9mg, 8.7mg, 19.2mg, 31.5mg and 2.0mg, respectively, while those in the pollen of P. thunbergii were 8.5mg, 9.4mg, 15.7mg, 35.3mg, and 1.8mg respectively. Vitamin C among them was abundant. (4) When the pollen grains of P. densiflora were pilverized for 40 minutes at 5,000rpm and P. thunbergii, for 50 minutes at 5,000rpm by overhead stirrer, the 100% of pollen pulverization was possible.

  • PDF

TRIALS OF GONADOTROPIN TO REGRESS OVARIAN CYSTS PROVOKED BY HORMONAL INDUCTION OF LACTATION

  • Dabas, Y.P.S.;Sud, S.C.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.5 no.2
    • /
    • pp.337-339
    • /
    • 1992
  • Successful induction of lactation in 5 nulliparous repeat breeding cows was achieved by administering diethyl stillboestrol (0.1 mg/kg B.W.) and hydroxyprogesterone caproate (0.25 mg/kg B.W.) for 3 days followed by reserpine (4 mg/day) for 4 days, and dexamethasone (16 mg/day) for one day. The treatment caused cystic ovarian condition in all the animals. Intravaginally progesteronesoaked sponges suppressed but did not eliminate the behavioural estrus. Administration of LHRH ($300{\mu}g$) regressed the cysts in all animals in the first instance but the cysts reappeared in 2 animals. One animal became pregnant and delivered a normal calf.

Relationship between Particle Density and Electrochemical Properties of Spherical LiMn2-xMxO4 (M = Al, Mg, B) Spinel Cathode Materials (구형 스피넬계 LiMxMn2-xO4 (M = Al, Mg, B) 양극소재의 입자치밀도와 전지성능간의 상관관계에 대한 연구)

  • Kim, Kyoung-Hee;Jung, Tae-Gyu;Song, Jun-Ho;Kim, Young-Jun
    • Journal of the Korean Electrochemical Society
    • /
    • v.15 no.2
    • /
    • pp.67-73
    • /
    • 2012
  • Spherical lithium manganese oxide spinel, $LiMn_{2-x}M_xO_4$ (M = Al, Mg, B) prepared by wet-milling, spray-drying, and sintering process has been investigated as a cathode material for lithium ion batteries. As-prepared powders exhibit various surface morphologies and internal density in terms of boron (B) doping level. It is found that the dopant B drives the growth of the primary particle and minimizes the surface area of the powder. As a result, the dopant enhances the internal density of the particles. Electrochemical tests demonstrated that the capacity of the synthesized material at 5 C could be maintained up to 90% of that at 0.2 C. The cycle performance of the material showed that the initial capacity was retained up to 80% even after 500 cycles under the high temperature of $60^{\circ}C$.

Origin of B, Br and Sr in Groundwater from Bukahn-myeon, Yeongcheon, Gyeongbuk Province, with Emphasis on Hydrochemistry (지하수의 수질화학적 특징과 붕소, 브롬, 스트론튬 성인에 대한 고찰)

  • Choo, Chang-Oh;Lee, Jin-Kook;Lee, Chang-Joo;Park, Ki-Ho;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
    • /
    • v.19 no.2
    • /
    • pp.235-250
    • /
    • 2009
  • Environmental elements such as B, Br, and Sr in groundwater from Bukahn-myeon, Yeongcheon, Gyeongbuk Province, were investigated in order to know their origin with emphasis on hydrochemistry. pH ranges from 7.37 to 8.39. B content is 0.41${\sim}$4.62 mg/L with an average 1.74 mg/L and Br content is 0${\sim}$3.24 mg/L with an average 2.22 mg/L, and Sr content is 0.93${\sim}$8.64 mg/L with an average 2.76 mg/L. The water types plotted by the Piper diagram are different but mostly $Ca-HCO_3$. Some constituents contributing to EC are Na, $SO_4$, Cl with high determinative coefficients($R^2$) of 0.85, 0.70, 0.90, respectively. The coefficients($R^2$) of Cl to Na, K, $SO_4$ are 0.54, 0.68, 0.53, respectively. It should be noted that there are high cocfficients($R^2$) of B-Sr and $Sr-SO_4$ with 0.65, 0.64, respectively. The Cl/Br ratios are 5.21${\sim}$30.70 due to significant depletion of Cl. The $SO_4/Cl$ ratios are 1.32${\sim}$27.24 with an average of 5.92, ascribed to abundant introduction of $SO_4$ or significant depletion of Cl. Chemical speciation calculated shows that B exists mostly as $H_3BO_3$ with less $H_2BO^-_3$ and Br exists as only $Br^-$. Sr exists mostly as $Sr^2$ with less $SO_4$. Saturation index represents that goundwater is supersaturated with respect to barite, kaolinite, illite, K-mica, and smectite while it is slightly undersaturated with respect to silica, gypsum, anhydrite, talc, chrysotile, feldspar, kaolinite, illite, K-mica, and smectite. The saturation index of celestine is -2.23${\sim}$-0.13 indicating more Sr can be incorporated into groundwater. Groundwater is still much undersaturated to halite. It is likely that the origin of S and Sr was related to the Yucheon volcanic rocks. Br might be originated from the local geological features with introduction of anthropogenic matters.

Antioxidant and tyrosinase inhibitory activity of white beech mushroom (Hypsizygus marmoreus) extracts (흰색 느티만가닥버섯 추출물의 항산화 활성 및 tyrosinase 저해 효과)

  • Kim, Su Cheol;Kim, Hye Soo;Cho, Soo Jeong
    • Journal of Mushroom
    • /
    • v.16 no.4
    • /
    • pp.324-330
    • /
    • 2018
  • The objective of this study was to evaluate antioxidant effect and tyrosinase inhibitory activity of white beech mushroom (Hypsizygus marmoreus) extracts. The white beech mushroom was extracted into hot water and methanol. Total polyphenol content was highest in the hot water extract ($8.4{\pm}3.27mg\;GAE/g$) compared to the methanol extract ($7.3{\pm}2.85mg\;GAE/g$). The flavonoids contents in hot water and methanol extracts were $3.8{\pm}3.81ug/mg$ and $2.5{\pm}1.95ug/mg$, respectively. The tyrosinase inhibitory activity of extract was increased in a dose dependent manner and tyrosinase inhibitory activity of extract (hot water extract, 69.72%; methanol extract, 52.67% at 40 mg/ml) was lower than those of positive control 2% arbutin (96%). The DPPH radical scavenging activity of the hot water and methanol extract was 80% and 74%, respectively. Hot water extract ($63.34{\pm}1.00uM\;TE/g$) were more effective in ORAC (oxygen radical absorbance capacity) value than methanol extract ($46.33{\pm}0.48uM\;TE/g$). The toxicity of hot water and methanol extracts was investigated using WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulphonate) assay on the B16BL6 melanoma cells.