45 resultados para 809
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啤酒酿造中野生酵母的研究吴文芳,张成刚,吕安国,李波(中国科学院沈阳应用生态所)金连武,蒋玲,孙喜春(辽宁铁岭市清河啤酒厂)所谓野生酵母,是指在啤酒酿造过程中出现的除培养酵母之外的所有酵母而言。威尔斯对野生酵母的定义是:任何未经严密选用与控制的酵母,...
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在PDA平板培养条件下,研究Cd、Pb及其复合污染对平菇菌丝体生长的影响以及平菇菌丝体对生长基质中Cd、Pb的生物富集作用.结果表明,在实验浓度范围内,菌丝生长势、菌落直径和菌丝体干重等均随着重金属浓度的增大而减弱(小)或降低.平菇菌丝体对Cd、Pb均具有生物富集作用,并且随着重金属浓度的增大菌丝体中重金属含量逐渐增大.Cd、Pb复合污染能促进平菇菌丝体对Pb的吸收,而抑制对Cd的吸收.
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A multi-phase model was developed and Tb(III) speciation in human blood plasma was studied. At a concentration below 3.744x 10(-4) mol/L (or at the concentration), Tb(III) is mostly bound to phosphate to form precipitate of TbPO4. As the concentration of Tb(III) increases, phosphate is exceeded and another kind of precipitate of Tb-2(CO3)(3) appears. Among soluble Tb(III) species, Tb(III) mainly distribute in [Tb (Tf)] at low concentration and in [Tb (HSAA, [Tb-2 (Tf)], [Th (IgG)], [Tb (Lactate)](2+), [Tb (CitArgH)] and free Tb(III) at high concentration.
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Sandwich-like heteropoly molybdochromophosphates of supermolecular compound [NH3(CH2)(6)NH3](2)H-3{Cr[Mo6O15(HPO4)(H2PO4)(3)](2)}. 4H(2)O has been hydrothermally synthesized and the single crystal structure has been determined by X-ray diffraction. The crystal data are has follows: triclinic, space group P (1) over bar a=12.156(2), b=12.809(3), c=13.530(3) Angstrom, alpha=102.46(3)degrees, beta=93.67(3)degrees, gamma=93.46(3)degrees, V=2046.9(7) Angstrom(3), Z=1, M-r=2768.69, D-c=2.246 g/cm(-3), F(000)=1337, mu=2.162 mm(-1). The structure has been refined to R=0.0666 and wR=0.1745 by full-matrix least-squares method. The title compound is composed of 1, 6-diaminohexane, water molecules, and {Cr[Mo6O15(HPO4)(H2PO4)(3)](2)}(7-) anion which consists of six oxygen atoms from two [Mo6P4] units with a sandwich-like transition metal atom Cr located at the center of symmetry.
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用人工神经网和多元回归方法对含2个碳的21个卤代化合物的35个化学位移进行计算机图谱模拟,结果表明,人工神经网络方法优于多元回归方法,同时此种方法处理这类问题有明显的优势。波谱模拟技术在有机化合物结构解析中是非常有用的方法。
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LnCl(3) reacted with C6H5CH2C5H4Na in THF (tetrahydrofuran) in the ratio 1.1 at room temperature for 1 h giving C(6)H(5)CH(2)C(6)H(4)LnCl(2) . nTHF, which reacted with C8H8K2/THF and the crystals obtained were recrystallized in DME to yield the title complex. The crystal structure of (C8H8) Ln (C6H5CH2C5H4). DME was determined revealing that the Gd complex has one conformation. One benzylcyclopentadienyl (eta(5)), one cyclooctatetraenyl (eta(8)) and the two oxygen atoms of DME (dimethoxyethane) are coordinated to Gd with the effective coordination number of 10.
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Eleven pairs of Undaria pinnatifida (Harv.) Suringar gametophytes were identified with random amplified polymorphic DNA (RAPD) technique. After screening 100 primers, 20 ten-base primers were determined for the RAPD analysis. A total of 312 polymorphic loci were obtained, of which 97.7% were polymorphic. The primer S198 was found to distinguish all the selected Undaria pinnatifida gametophytes. The genetic distances between each two of the twenty-two U. pinnatifida gametophytes ranged from 0.080 to 0.428, while the distances to the Laminaria was 0.497 on average. After reexamination, two sequences characterized amplification region (SCAR) markers were successfully converted, which could be applied to U. pinnatifida germplasm identification. All these results demonstrated the feasibility of applying RAPD markers to germplasm characterization and identification of U. pinnatifida gametophytes, and to provide a molecular basis for Undaria breeding.
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A new poly brominated dibenzylphenol named as rhodomevoidin was isolated from Rhodomela confervoides. Its structrue was elucidated as 3-bromo-4, 5-bis (2, 3-dibromo-4, 5-dihydroxybenzyI)pyrocatechol by spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.
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目的 研究祁连獐牙菜Swertia przewalskii全草的化学成分。方法 采用硅胶柱层析进行分离纯化,通过波谱方法及化学关联进行结构鉴定;结果 分离纯化出15个化合物,分别鉴定为:1,7-二羟基-3,8-二甲氧基San酮(Ⅰ),1,8-二羟基-3,7-二甲氧基San酮(Ⅱ),1,7,8-三羟基-3-甲氧基San酮(Ⅲ),1,3,7,8-四羟基San酮(Ⅳ),1-O-β-D-吡喃葡萄糖基-7-羟基-3,8-二甲氧基San酮(Ⅴ),1-O-β-D-吡喃葡萄糖基-8-羟基-3,7-二甲氧基San酮(Ⅵ),7-O-β-D-吡喃葡萄糖基-1,8-二羟基-3-甲氧基San酮(Ⅶ),1-O-[β-D-吡喃木糖(1→6)-β-D-吡喃葡萄糖]-7-羟基-3,8-二甲氧基San酮(Ⅷ),1-O-[β-D-吡喃葡萄糖]-1,7-二羟基-3-甲氧基S sgmk(X),木犀草素(Ⅺ),齐墩果酸(Ⅻ),乌苏酸(XⅣ)和龙胆苦苷(XV)。结论 化合物Ⅳ-Ⅷ,Ⅺ,Ⅻ,XⅣ和XV均为首次从该种植物中分得。
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在贵州喀斯特区域一块典型的退耕弃荒洼地中央和周边坡面采集了4个土壤剖面,研究土壤有机碳(SOC)含量和δ^13Corg值的变化.结果表明,坡面不同土壤层次SOC的变化范围为6.0-92.3 mg·kg^-1,并沿着土壤层次的加深迅速降低,变化幅度远远大于洼地土壤剖面(6.3-26.7 mg·kg^-1).坡面土壤δ^13Corg介于-25.103‰和-23.666‰之间,但各剖面土层内部δ^13Corg变化趋势不一致.洼地土壤δ^13Corg介于-23.495‰和-20.809‰之间,并随着土壤层次的加深δ^13Corg逐渐增加.洼地土壤剖面层次内C4-C占SOC的比例随土壤层次的加深逐渐增加,与林-农生态系统转变过程中的变化趋势相反;土壤δ^13Corg与C3-C之间呈显著相关性(R^2=0.7806,n=7),对δ^13Corg起到主要影响作用的是退耕弃荒后新加入的C3-C.
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岩石化学与微量元素研究表明,在强经泥质灰岩中,SiO2和Au、As、Sb含量增高,CaO、CO2和MgO含量降低;在强碳酸盐化泥质灰岩中,AgO和CO2含量增高,SiO2含量降低;不同蚀变与矿化岩石的稀土含量和配分模式与未蚀变泥质灰岩基本一致。流体包裹体研究揭示,成矿溶液为富Cl^-型和富SO4^2-型,爆裂温度为183-378℃。同位素研究指示,δ^34S=(6.471-21.965)×10^-3,δ^18O=(9.3-11.6)×10^-3,δD=(-70--77)×10^-3,^206Pb=19.551-20.05,^027Pb/^204Pb=15.690-16.240,^208Pb/^204Pb=38.710-40.137;成矿流体具有岩浆水和大气降水相混合的特点,成矿物质具有壳-幔混合特征。