991 resultados para 7140-203


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4-(2-氨基噻唑)-间苯二酚为柱前衍化剂液相色谱/电化学检测Fe、Co、Ni格日勒,李惠梅,李南强,汪尔康(中国科学院长春应用化学研究所电分析化学开放实验室,北京大学化学系,长春,130022)关键词液相色谱,Fe,Co,Ni,4-(2-氨基噻唑)...

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采用聚丙烯酰胺凝胶垂直板电泳方法分析有亲缘关系的37个品种(包括15个品种的亲本来源)萌发6天的大豆子叶POD同工酶谱。结果表明,不同品种POD同工酶谱共显示5~10条酶带,分A、B、C三区。以B区酶带色度深浅及数目变化为分类标准,可分为四种酶型:PB_1型、PB_2型、PB_3型和PB_4型。根据此酶型分析了每一个组合的品种与其两亲本。其中6个品种呈现偏父本酶型,6个品种呈现新酶型,2个品种的酶型与父母相同,1个品种呈现偏母本酶型。同时测定了13个组合的36个品种的POD比活力,结果指出:后代品种POD比活力都低于或介于父母本之间,后代比双亲POD比活力有逐渐降低的趋势。

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用辐射接枝工艺合成了功能高分子膜活性材料,并对其进行了表征,测定了以此为活性材料的离子选择电极性能。结果发现,硫酸根电极在10~(-1)—10~(-3)mol/L Na_2SO_4溶液中响应时间<70s,斜率为52mV/PSO_4~(2-);氯离子电极的线性范围1×10~(-1)—2×10~(-4)mol/L,检测下限为8×10~(-5)mol/L,稳定性好,寿命长,响应时间<5s,内阻<60kΩ,抗毒化能力强。从稀土离子选择电极中发现,以辐射接枝工艺合成的材料比化学法合成的好,前者斜率为53 mV/PGd,后者斜率为46 mV/PGd;预辐照接枝工艺合成的材料比共辐照接枝工艺的好些。

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标题化合物SmCl_3(THF)_4(M_r=545.2)晶体属正交晶系,空间群为Pdd 2。晶胞参数为a=9.211(4),6=16.436(6),c=29.666(12);V=4491(3) ~3;Z=8,D_c=1.61g.cm~(-3),F(000)=2184,μ_c=30.3cm~(-1)。最终的偏因子R=0.063,R_(to)=0.062。Sm~(3+)与三个Cl~-及四个四氢呋喃分子中氧原子配位,形成一个五角双锥的空间结构,其中二个氯原子分别位于二个顶点位置。分子中有一个通过Sm~(3+)及Cl~-的C_2轴。Sm-Cl及Sm-0的平均键长分别为2.683(5)及2.469(11)。

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双(环戊二烯基)镱(Ⅱ)四氢呋喃配合物(η~5-C_5H_5)_2Yb(THF)_2通过环辛二烯基钾(KC_8H_(11))还原(C_5H_5)_2YbCl·THF而得到,经元素分析、红外光谱表征,并测定了其晶体结构。配合物属单斜晶系,C2/c空间群,晶体学参数a=1.3564(4),b=0.9569(3),c=1.4747(6)nm;β=109.90(3)°;V=1.79975(118)nm~3;D_c=1.65·cm~(-3);μ_C=54.7cm~(-1)(Mo);F(000)=880,Z=4。最后一致性因子R=0.079,R_w=0.081。Yb~(2+)的配位数为8。

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The ultra-thin modified PEO (polyethylene oxide)-LiClO4 polymer electrolyte film (50-mu-m) was obtained by solution-casting technique. Impedance spectra were taken on the cells consisting of above PEO film electrolyte and ion-blocking or nonblocking electrodes. The ambient conductivity as high as 1.33 X 10(-4)S cm-1 could be achieved for PEO electrolyte modified by the crosslinking. It was shown that the resistance at the interface between solid polymer electrolyte and lithium electrode is growing with increasing the storage time. At high temperature, as 96-degrees-C, the ionic transport is clearly controlled by diffusion.

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The net charges at atoms in the high-temperature superconductor TlBa2Can-1CunO2n+3 (n = 1 to 3) are calculated by means of the tight-binding approximation based on the EHMO method. The results indicate that the charge distribution in this kind of compounds possesses a specially layered arrangement. An insulating Ba-Ba layer is inserted between the Cu-O layer and the Tl-O layer. There may exist a weak coupling between the Cu-O layer and the Tl-O layer through the interaction of the same O(2) atom with both the Cu atom and the Tl atom. The existence of the Ca in the compounds can cause the valence fluctuation at the Cu atom. The calculated electric field gradients at atoms implies that the conducting electron or hole may move in the Cu-O layer, which is closest to the Tl-O layer, along the a-b plane.

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Electrodeposition of the phenothiazine mediator titrant toluidine blue onto a glassy carbon substrate at an appropriate potential was used to construct a toluidine blue chemically modified electrode (CME) exhibiting electrocatalytic reduction for myoglobin and hemoglobin. The CME catalyzed the hemoprotein electroreduction at the reduction potential of the mediator molecule. When the CME as used as a detector for flow injection analysis at a constant applied potential of -0.30 V vs. a saturated calomel electrode, it gave detection limits of 20 and 50 ng (1.2 and 0.78 pmol) injected myoglobin and hemoglobin, respectively, with a dynamic linear concentration range over 2 orders of magnitude. After a brief equilibration period, the CME retained nearly 90% of its initial myoglobin response over 8 hours of continuous exposure to the flow-through system.

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Transmittance spectroelectrochemistry can be performed using a group of cylindrical microelectrodes. A dependence of absorbance on electrolytic charge during the potential step was derived. The rate constant of catalytic reaction of the ferrocyanide-ascorbic acid system was determined using single potential step-open circuit relaxation chronoabsorptometry. This is the first report that the reaction can still be considered as a pseudo-first-order reaction when the concentration of ascorbic acid is close to and even slightly lower than the concentration of ferrocyanide. The determined rate constant is in agreement with the reported value. The reason is that the diffusion of ascorbic acid toward electrode surface is contractive and the diffusion of the electrogenerated ferricyanide from the electrode surface to the bulk of solution is expansive.

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本文运用角重迭模型(AOM)在考虑其全部四个参数e_σ、e_π、e_δ及e_φ的基础上首次对Eu~(3+):LaOX(X=Cl,Br,I)晶体在晶场作用下的能级劈裂进行了拟合.

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The giant basal spicules of the siliceous sponges Monorhaphis chuni and Monorhaphis intermedia (Hexactinellida) represent the largest biosilica structures on earth (up to 3 m long). Here we describe the construction (lamellar organization) of these spicules and of the comitalia and highlight their organic matrix in order to understand their mechanical properties. The spicules display three distinct regions built of biosilica: (i) the outer lamellar zone (radius: >300 mu m), (ii) the bulky axial cylinder (radius: <75 mu m), and (iii) the central axial canal (diameter: <2 mu m) with its organic axial filament. The spicules are loosely covered with a collagen net which is regularly perforated by 7-10 mu m large holes; the net can be silicified. The silica layers forming the lamellar zone are approximate to 5 mu m thick; the central axial cylinder appears to be composed of almost solid silica which becomes porous after etching with hydrofluoric acid (HF). Dissolution of a complete spicule discloses its complex structure with distinct lamellae in the outer zone (lamellar coating) and a more resistant central part (axial barrel). Rapidly after the release of the organic coating from the lamellar zone the protein layers disintegrate to form irregular clumps/aggregates. In contrast, the proteinaceous axial barrel, hidden in the siliceous axial cylinder, is set up by rope-like filaments. Biochemical analysis revealed that the (dominant) molecule of the lamellar coating is a 27-kDa protein which displays catalytic, proteolytic activity. High resolution electron microscopic analysis showed that this protein is arranged within the lamellae and stabilizes these surfaces by palisade-like pillars. The mechanical behavior of the spicules was analyzed by a 3-point bending assay, coupled with scanning electron microscopy. The load-extension curve of the spicule shows a biphasic breakage/cracking pattern. The outer lamellar zone cracks in several distinct steps showing high resistance in concert with comparably low elasticity, while the axial cylinder breaks with high elasticity and lower stiffness. The complex bioorganic/inorganic hybrid composition and structure of the Monorhaphis spicules might provide the blueprint for the synthesis of bio-inspired material, with unusual mechanical properties (strength, stiffness) without losing the exceptional properties of optical transmission. (C) 2007 Elsevier Inc. All rights reserved.

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Sequence-related amplified polymorphism (SRAP) is a novel molecular marker technique designed to amplify open reading frames (ORFs). The SRAP analytic system was set up and applied to Porphyra germplasm identification in this study for the first time. Sixteen Porphyra lines were screened by SRAP technique with 30 primer combinations. In the analysis, 14 primer combinations produced stable and reproducible amplification patterns in three repetitive experiments. Among the total 533 amplified fragments, 522 (98%) were polymorphic, with an average of 38 fragments for each primer combination, ranging in size from 50 to 500 bp. The 533 fragments were visually scored one by one and then used to develop a dendrogram with Unweighted Pair-Group Method Arithmetic Average (UPGMA), and the 16 Porphyra lines were divided into two major groups at the 0.68 similarity level. From the total 533 fragments, I I amplified by two primer combinations, ME1/EM1 and ME4/EM6, were used to develop the DNA fingerprints of the 16 Porphyra lines. The DNA fingerprints were then converted into binary codes, with I and 0 representing presence and absence of the corresponding amplified fragment, respectively. In the DNA fingerprints, each of the 16 Porphyra lines has its unique binary code and can be easily distinguished from the others. This is the first report on the development of SRAP technique and its utilization in germplasm identification of seaweeds. The results demonstrated that SRAP is a simple, stable, polymorphic and reproducible molecular marker technique for the classification and identification of Porphyra lines. (c) 2007 Elsevier B.V. All rights reserved.

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本文分别提取了中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的眼柄总RNA。用无DNA污染的眼柄总RNA为模板,根据日本对虾的MIH设计兼并引物P1和P2,进行RT-PCR扩增,在适宜的反应条件下,均分别得到一特异性的产物。以蓝对虾基因组DNA为模板的PCR扩增也能得到一与特异性cDNA片段大小相似的特异性的DNA片段。分别将这些片段亚克隆到载体中进行测序,测得中国对虾特异性cDNA片段由203个碱基组成,中华绒螯蟹、鹰爪虾、蓝对虾的特异性cDNA片段及蓝对虾的特异性DNA片段由215个碱基组成,其中蓝对虾特异性cDNA与由蓝对虾的基因组DNA扩增得到的特异性DNA片段的碱基序列几乎完全相同。利用互联网上的在线工具Fasta3查找这些cDNA推定的氨基酸序列的相似序列,可以发现大量的甲壳动物的CHH家族的神经肽与它们相似。在所有的相似序列中,分别由中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的特异性cDNA片段推定的氨基酸序列与蜕皮抑制激素(MIH)的相似度最高,这一结果提示分别由中国对虾、中华绒螯蟹、鹰爪虾和蓝对虾的眼柄特异性cDNA片段推定的氨基酸序列可能是这四种甲壳动物的MIH片段。根据核苷酸数据和氨基酸数据,比较这四种甲壳动物的MIH以及已发表的六种MIH之间的相似度,同时分析这十种MIH的系统进化关系,结果是蓝对虾、鹰爪虾和中华绒螯蟹的MIH相似性较高,亲缘关系较近,这与物种的系统演化不相符。

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塔螺科是软体动物门中种类最多的科,全世界种类超过5,000种,在分类系统学中占有相当重要的地位。塔螺为世界性分布,以热带、亚热带和温带海域分布最多。塔螺科动物肉体可食用,贝壳造型独特、色泽鲜丽,深受贝壳收藏爱好者喜爱。作为重要的捕食者和被捕食者,塔螺是底栖生物食物链的重要环节。 中科院海洋生物标本馆现馆藏大量的塔螺标本,但一直没有进行系统的分类学研究,仅有一些零星的报道,咫需进行深入研究。本论文主要采用传统的形态分类方法结合其生态习性和地理分布,对其进行系统的分类学研究,详细描述中国的属、种及分布,澄清近似种和疑难种,发现新种和新记录种,从而丰富了我国海洋生物多样性的资料。同时研究了该动物类群区系组成分析和动物地理学,阐明了我国塔螺科的区系特点,并确定其在世界上的地位。 经系统研究和鉴定,发现中国科学院海洋生物标本馆馆藏塔螺种类共203种,隶属于8亚科,54属,其中发现1新亚属,16新种,81新记录种。我国塔螺动物在区系组成上属印度-马来区系的一部分。中国海塔螺科区系组成中,以热带和亚热带成分占绝对优势,在这两个区系中共发现分布种类160种,占总种数的79.8%。中国海塔螺科物种组成与日本南部和菲律宾塔螺的物种组成有些差异,本文描述的203种笔螺与日本共有种为93种,与菲律宾共有种为63种,相似性指数分别为41.99%和41.86%。塔螺科种大多属热带和亚热带种类,因此在中国常见于浙江、福建、广东、台湾、海南附近海域和西沙、南沙群岛。