930 resultados para 3-d visualization


Relevância:

80.00% 80.00%

Publicador:

Resumo:

Three new compounds, [ZnL1.5(H2O)(SO4)]. 6H(2)O 1, [ZnL1.5(H2O)(2)][NO3](2). 2H(2)O 2 and [CdL1.5(H2O)(2)(SO4)]. 4H(2)O 3 were obtained from self-assembly of the corresponding metal salts with 1,1'-(1,4-butanediyl)bis(imidazole) (L). In both 1 and 2 zinc ion is five-co-ordinated, showing a less-common trigonal bipyramidal co-ordination polyhedron, while cadmium ion of 3 is six-co-ordinated with a common octahedral arrangement. The sulfate ions of 1 and 3 are co-ordinated, however the nitrate ions of 2 are not. Each of the three compounds is composed of a (6, 3) network with the hexagonal smallest circuit containing six metal ions and six L; each L is co-ordinated to two metal ions, acting as a bridging ligand. In 1 the 2-D sheet of (6, 3) networks is interpenetrated in an inclined mode by symmetry related, identical sheets to give an interlocked 3-D structure, while the (6, 3) networks of both 2 and 3 stack in a parallel fashion to construct frameworks having channels.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Thirty - two title complexes (ROCOCHRCH2SnCl3)-C-1 . (2 - HOC6H4CH = NC6H4 - X) (R = Me, Et, n - Bu; R-1 = H, Me; X = H,4' - Cl, 3' - Pr, 3' - OH, 3', 4' - Cl-2, 4' - OMe) were synthesized and characterized by elemental analysis,UV - vis, IR, H-1 NMR. The crystal structure of n - BuOCOCH2CH2SnCl3 . (2 - HOC6H4CH - NC6H4OMe - 4') were determined by the X - ray diffraction analysis, The crystal belongs to monoclinic system, with a = 1.4661 (3)nm, b = 0.9307 (2)nm, c = 1.7888 (4)nm, beta = 94.04 (3)degrees, V = 2.4348nm(3), D-c = 1.581mg/m(3), Z = 4, F(000) = 1160, mu = 1.405mm(-1), R = 0.0354, R-w = 0,0486, space group: P2(1)/c. The complexes exist as a discrete monomer. The tin atom has a distorted octahedral geometry due to intramolecular coordination of the carbonyl oxygen and the phenolic oxygen of the Schiff base ligands, The coordination number of tin atom is 6.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

目的:研究蒺藜(Tribulus terrestris L.)中生物活性物质。方法:用硅胶柱色谱、HPLC进行分离,根据光谱数据鉴定其结构。结果:分离纯化得到两种呋甾皂苷,确定其结构为26-O-β-D-吡喃葡糖基-(25R,S)-5α-呋甾-12-羰基-20(22)-烯基-3β,26-二醇-3-O-β-D吡喃葡糖基(1→4)-β-D-吡喃半乳糖苷(I);26-O-β-D吡喃葡糖基-(25R)-5α-呋甾-12-羰基-3β,22α,26-三醇-3-O-β-D-吡喃葡糖基(1→2)-β-D-吡喃半乳糖苷(Ⅱ)。结论:I,Ⅱ均为新化合物

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The photoluminescence of Ce3+, Tb3+ and Sm3+, and energy transfer from Ce3+ to Tb3+, Dy3+ and Sm3+ in Mg2Y8(SiOd(4))(6)O-2 are reported and discussed. The Ce3+ ion shows blue luminescence under UV excitation, and occupies simultaneously the 4f site and 6h site in the host lattice. The optimum concentrations for the D-5(3) and D-5(4) emissions of Tb3+ and the (4)G(5/2) emission of Sm3+ are determined to be 0.04, 0.20 and 0.10 mol in every mol of Mg2Y8(SiO4)(6)O-2, respectively. The critical distances responsible for the cross-relaxation between the D-5(3)-D-5(4) and F-7(6)-F-7(0) transitions of Tb3+ and between the (4)G(5/2)-F-4(9/2) and H-6(5/2)-F-4(9/2) transitions of Sm3+ are estimated to be 1.43 and 1.06 nm, respectively. Both Tb3+ and Dy3+ can be sensitized by Ce3+, but Ce3+ and Sm3+ quench each other.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本文用激光光散射和光学显微镜方法研究了聚甲基丙烯酸甲酯/聚醋酸乙烯酯共混体系不稳相分离过程最大散射强度I_m(t,T)和相应波矢q_m(t,T)随时间变化规律及相区的逾渗结构.实验结果表明:I_m(T,t)和q_m(t,T)与时间t满足简单的标度关系I_m(t,T)~t~β,q_m(t,T)~t~(-α),且标度关系β=3α成立.揭示了相态结构的分维特征.给出了计算相态结构分维数的简便方法,其分维数D值约为1.64±0.03.与逾渗模型给出的D值接近.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Bis(t-butylcyclopentadienyl)lanthanide chloride (Ln = Nd or Gd) reacts with one equivalent of methyllithium in ether/tetrahydrofuran to give the complex [(C5H4tBu)2LnCH3]2 (Ln = Nd or Gd). The structure of [(C5H4tBu)2NdCH3]2 has been determined by X-ray analysis. The crystals are monoclinic of space group Cm with a = 9.538(2), b = 23.298(4), c = 9.505(3) angstrom, beta = 119.53(2)-degrees, V = 1828.0(7) angstrom 3, D(calc.) = 1.458 g/cm3 and Z = 2 for the dimer. The two (C5H4tBu)2Nd units in the dimer are connected by asymmetrical methyl bridges with independent Nd-C bond lengths of 2.70(2) and 2.53(2) angstrom and Nd-C-Nd angles of 94.7(9) and 87.3(6)-degrees.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The complexes named in the title (eta-5-C9H7)3Ln.OC4H8 (Ln = Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and H-1-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (eta-5-C9H7)3Nd.OC4H8 (1) and (eta-5-C9H7)3Gd.OC4H8 (2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6(3) with unit cell parameters a = b = 11.843(3), c = 10.304(4) angstrom, V = 1251.7(9) angstrom-3, D(c) = 1.49 g.cm-3, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) angstrom, V = 1235.4(6) angstrom-3 D(c) = 1.54 g.cm-3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squares to final discrepancy indices of R = 0.049, R(w) = 0.053 using 925 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 1, and R = 0.023, R(w) = 0.025 using 1327 independent reflections with I greater-than-or-equal-to 3-sigma(I) for 2. Coordination numbers for Nd3+ and Gd3+ are 10; the average bond lengths Nd-O and Gd-O are 2.557(21) and 2.459(13) angstrom, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Reaction of lanthanoid trichloride with two equivalents of sodium t-butylcyclopentadienide in tetrahydrofuran affords bis(t-butylcyclopentadienyl)lanthanoid chloride complexes (t-BuCp)2LnCl. nTHF (Ln = Pr, Nd, n = 2; Ln = Gd, Yb, n = 1). The compound (t-BuCp)2PrCl.2THF (1) crystallizes from THF in monoclinic space group P2(1)/c with unit cell dimensions a = 15.080(3), b = 8.855(2), c = 21.196(5) angstrom, beta = 110.34(2)degrees, V = 2653.9 angstrom-3 and D(calcd) = 1.41 g/cm3 for Z = 4. The central metal Pr is coordinated to two t-BuCp ring centroids, one chlorine atom and two THF forming a distorted trigonal bipyramid. The crystal of (t-BuCp)2YbCl.THF (2) belongs to the monoclinic crystal system, space group P2(1)/n with a = 7.726(1), b = 12.554(2), c = 23.200(6) angstrom, beta = 97.77(2)degrees, V = 2229.56 angstrom-3, D(calcd) = 1.50 g/cm3 and Z = 4. The t-BuCp ring centroids, the chlorine atom and the oxygen atom of the THF describe a distorted tetrahedron around the central ion of ytterbium.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Circadian growth rhythm of the juvenile sporophyte of the brown alga Undaria pirznatifida was measured with the computer-aided image analysis system in constant florescent white light under constant temperature (10 degrees C). The growth rhythm persisted for 4 d in constant light with a free-running period of 25. 6 h. Egg release from filamentous gametophytes pre-cultured in the light - dark regime was evaluated for six consecutive days at fixed time intervals in constant white light and 12 h light per day. Egg release rhythm persisted for 3 d in both regimes, indicating the endogenous nature. Temporal scale of egg release and gametogenesis in 18, 16, 12 and 8 h light per day were evaluated respectively using vegetatively propagated filamentous gametophytes. Egg release occurred 2 h after the onset of dark phase and peaked at midnight. Evaluation of the rates of oogonium formation, egg release or fertilization revealed no significant differences in four light-dark regimes, indicating; the great plasticity of sexual reproduction. No photoperiodic effect in gametogenesis in terms of oogonium formation and egg release was found, but fertilization in short days was significantly higher than in long days. Results of this investigation further confirmed the general occurrence of circadian rhythms in inter-tidal seaweed species.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Heat shock protein 70 (HSP70) is an important member of the heat shock protein superfamily, and it plays a key role in the process of protecting cells, facilitating the folding of nascent peptides and responding to stress. The cDNA of bay scallop Argopecten irradians HSP70 (designated AIHSP70) was cloned by the techniques of homological cloning and rapid amplification of cDNA end (RACE). The full length of AIHSP70 cDNA was 2651 bp in length, having a 5' untranslated region (UTR) of 96 bp, a 3' UTR of 575 bp, and an open reading frame (ORF) of 1980 bp encoding a polypeptide of 659 amino acids with an estimated molecular mass of 71.80 kDa and an estimated isoelectric point of 5.26. BLAST analysis revealed that the AIHSP70 gene shared high identity with other known HSP70 genes. Three classical HSP signature motifs were detected in AIHSP70 by InterPro, analysis. 3-D structural prediction of AIHSP70 showed that its N terminal ATPase activity domain and,C terminal substrate-binding domain shared high similarity with that in human heat shock protein 70. The results indicated that the AIHSP70 was a member of the heat shock protein 70 family. A semi-quantitive RT-PCR method was used to analyse the expression of AIHSP70 gene after the treatment of naphthalin which is one kind of polycyclic aromatic hydrocarbon (PAH) and the challenge of bacteria. mRNA expression of AIHSP70 in scallop was up-regulated significantly after the stimulation of naphthalin and increased with increasing naphthalin concentration. A clearly time-dependent expression pattern of AIHSP70 was observed after the scallops were infected by Vibrio anguillarum, and the mRNA expression reached a maximum level at 8 h and lasted to 16 h, and then dropped progressively. The results indicated that AIHSP70 could play an important role in mediating the environmental stress and immune response in scallop. (c) 2006 Elsevier Ltd. All rights reserved.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Gas hydrate samples were obtained firstly in China by drilling on the northern margin of South China Sea (SCS). To understand the formation mechanism of this unique accumulation system, this paper discusses the factors controlling the formation of the system by accurate geophysical interpretation and geological analysis, based on the high precision 2-D and 3-D multichannel seismic data in the drilling area. There are three key factors controlling the accumulation of the gas hydrate system in fine grain sediment: (1) large volume of fluid bearing methane gas Joins the formation of gas hydrate. Active fluid flow in the northern South China Sea makes both thermal gas and/or biogenic gas migrate into shallow strata and form hydrate in the gas hydrate stability zone (GHSZ). The fluid flow includes mud diapir and gas chimney structure. They are commonly characterized by positive topographic relief, acoustic turbidity and push-down, and low reflection intensity on seismic profiles. The gas chimneys can reach to GHSZ, which favors the development of BSRs. It means that the active fluid flow has a close relationship with the formation and accumulation of gas hydrate. (2) The episodic process of fracture plays an important role in the generation of gas hydrate. It may provide the passage along which thermogenic or biogenic gas migrated into gas hydrate stability zone (GHSZ) upward. And it increases the pore space for the growth of hydrate crystal. (3) Submarine landslide induced the anomalous overpressure activity and development of fracture in the GHSZ. The formation model of high concentration gas hydrate in the drilling sea area was proposed on the basis of above analysis.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Based on the Estuarine, Coastal and Ocean Modeling System with Sediments (ECOMSED) model, a 3-D hydrodynamic-transport numerical model was established for the offshore area near the Yangtze Estuary in the East China Sea. The hydrodynamic module was driven by tide and wind. Sediment module included sediment resuspension, transport and deposition of cohesive and non-cohesive sediment. The settling of cohesive sediment in the water column was modeled as a function of aggregation (flocculation) and deposition. The numerical results were compared with observation data for August, 2006. It shows that the sediment concentration reduces gradually from the seashore to the offshore area. Numerical results of concentration time series in the observation stations show two peaks and two valleys, according with the observation data. It is mainly affected by tidal current. The suspended sediment concentration is related to the tidal current during a tidal cycle, and the maximum concentration appears 1 h-4 h after the current maximum velocity has reached.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

琼胶是一种从石花菜等红藻中提取的,目前生产工艺和结构等方面研究比较成熟的海藻多糖,广泛应用于医药、仪器等行业。但是,海藻多糖因为具有分子量大,粘度大,溶解度较小的等特点,而使其应用范围受到限制。利用降解的手段对其进行修饰,降低分子量和粘度,改善溶解性,可以拓展其应用范围。并且根据文献报道,琼 胶寡糖具有一些特殊的生物活性,如抗氧化性,抗炎症等。因此,对琼胶降解的研究具有生要意义。本研究中,为了选择一种合适的降解方法,进行了几种水解方法的尝试,其中包括在不同湿度和酸度下盐酸水解,过氧化氢和醋酸催化水解,Fenton体系羟基自由基降解。对于酸水解和Fenton体系氧化还原降解方法,通过粘度法对反应的速度进行了比较,表明氧化还原降解反应中琼胶的粘度降低比较快,并且具有代表性和新意,确定为本实验的降解琼胶的方法并对氧化还原降解所得的产物进行了活性实验。通过模仿自然界普遍存在的氧化还原降解反应,利用Vc诱导的Fenton体系产生的羟基自由基氧化还原降解琼胶得到低分子量的琼胶。降解产物经过高速离心、60%乙醇沉淀,除去分子量比较大的降解产物和磷酸盐,得到可溶于60%乙醇的分子量估计小于3000的降争产物,其产率为85%。利用经Sephadex-G25凝胶色谱分离所香的不同分子量的级分进行分子量和α-葡萄糖苷酶抑制活性关系的实验。降解产物对α-葡萄糖苷酶的抑制率和各级分的浓度呈线性正相关,并且各级分的IC_(50)则随着分子量的降低而降低。另外,对所得的降解产物混合物进行了红外吸收光谱、质子去偶核磁共震碳谱和负离子基质辅助激光诱导-飞行时间质谱结构分析。结果表明,氧化还原降解反应的专一性差,在得到寡糖的同时,在光谱图中出现一些比较复杂的副产物的结构信息。最后,根据MTT法的原理,以有体皮肤成纤维细胞为材料,通过紫外线辐射产生自由基造成氧化损伤,研究降解产物对成纤维细胞的保护作用。当无紫外线辐射时,降解产物对成纤维细胞具有显著的促进生长增殖作用:当经UVa、UBb辐射时则可以显著地表现出对损伤的保护作用,并且这种促进生长和保护作用呈显著的量效关系,表明降解产物具有清除基自由基的作用。但是,因为氧化还原降解以应的机理尚不十分明的以及琼羟胶的特殊结构,使得反应的副产物很难预测,也就使得分离工作难以进行,所以,根据目前所得的信息,尚不能确定是降解产物的什么级分产生的以上两种生物活性。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本论文研究了胶洲湾、东海和渤海的蓝细菌(Synechococcus)、生物量、异养细菌生物量和生产力的生态学特点。并在汇泉湾、渤海和东海用分极增减法对海洋蓝细菌在微型食物环(the microbial loop)中的作用进行了初步研究。在以上海区调查研究的时间如下:胶州湾:1993年2月、5月、9月11月,1996年5月、1999年3月、5月和12月。汇泉湾:1996年4月至1998年4月。东海:1997年2-3月,1998年7月。渤海1998年9-10月,1999年4-5月。研究结果如下:胶州湾:蓝细菌生物量的变化范围是11.4-0.03 mgC/m~3,季节变化是夏季>秋季和春季>冬季。其水平分布是除夏季蓝细菌生物量是沿岸浅水区向湾外递减外,其它三季(春、秋和冬季)是由湾外向湾内至沿岸浅水区递减。蓝细菌生物量与海水温度周年变化正相关,与季节海水温度的关系是秋、冬季分布变化一致,春、夏季分布变化相反。海水温度是影响胶州湾蓝细菌生物量分布变化的主要原因。异养细菌生物量和生产力的变化范围分别是29.8-1.62 mgC/m~3; 129.12-1.92 mgC/m~3.d。季节变化都是夏季>秋季、春季>冬季。夏季的异养细菌生物量和生产力水平分布趋势与蓝细菌生物量的分布变化相同。海水温度对异养细菌生产力的影响较对异养细菌生物量的影响大。异养细菌生产力相比(BP:PP)的变化在0.58-0.02之间,季节分布变化是夏季>秋季、春季>冬季。夏季表层的BP:PP由沿岸浅水区向湾心、湾口和湾外递减。东海:蓝细菌生物量的变化范围是46.72-0.011 mgC/m~3,夏季高平均是23.59 mgC/m~3,冬季低平均是3.61 mgC/m~3。冬季蓝细菌生物量的水平分布明显受黑潮的影响,在表面和20米层是由东南向西北方向递减。其垂直分布是冬季表层和20米层>底层,夏季是20米层>表层>底层;在连续站冬111站和410站变化都是中层>底层>表层。异养细菌生物量和生产力的变化范围分别是17.2-4.4 mgC/m~3(1997.2);376.8-7.2 mgC/m~3.d。异养细菌生产力夏季高平均是35.1 mgC/m~3.d。异养细菌生物量的水平分布是由沿岸向外海递增(1997.2),异养细菌生产力的水平分布是冬季异养细菌生产力在32度断面有由沿岸向外递减趋势,PN断面的变化与冬季相似。垂直分布,冬季和夏季的异养细菌生产力的垂直变化在2断面是底层大于表面,PN断面则是表层大于底层,32度断面大多断站是底层大于表层。在连续站冬季111站异养细菌生产力的变化是底层>中层>表层,409站的变化是中层>底层>表层,夏季111站和410站都是中>底层>表层。异养细菌生物量(1997.2)表层分布变化与海水温度分布变化相似,底层变化相反。异养细菌生产力与初级生产力相比(BP:PP),冬季在0.04-0.30之间,平均为0.17;夏季在0.20-0.43之间平均0.32。冬季在长江口附近BP:PP有一个高值区是0.30,夏季在111站附近有一个高值区是0.43。从连续站111站和409’站观测发现底层的BP:PP明显高于表层。渤海:蓝细菌生物量秋季(16.6-0.37 mgC/m~3)比春季(0.44-0.015 mgC/m~3)高。其秋季的水平分布与海水盐度水平分布相同,与海水温度水平分布相反。异养细菌生产力秋季(189-62.2 mgC/m~3.d)与春季(193.2-49.8 mgC/m~3.d)相当。但秋季捕层BP普遍小于底层,而春季是表层普遍大于底层。根据颗粒分级培养实验结果,海洋蓝图细菌在微型食物环中的作用如下:在汇泉湾的春季和秋季蓝细菌可能主要被小型浮游动物(microzooplankton 20-200 μm)捕食。在渤海的春季和秋季也是同样结果。但在东海夏季的111站和410站附近(东海大陆架中部)微型浮游动物(nanozooplankton 2-20 μm)对蓝细菌的捕食压力明显。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Two biological aerated filters (BAF) were setup for ammonia removal treatment of the circulation water in a marine aquaculture. One of the BAFs was bioaugmented with a heterotrophic nitrifying bacterium, Lutimonas sp. H10, where the ammonia removal was not improved and the massive inoculation was even followed by a nitrification breakdown from day 9 to 18. The nitrification was remained stable in control BAF operated under the same conditions. Fluorescent in situ hybridization (FISH) with rRNA-targeted probes and cultivable method revealed that Lutimonas sp. H10 almost disappeared from the bioaugomented BAF within 3 d, and this was mainly due to the infection of a specific phage as revealed by flask experiment, plaque assay and transmission electron observation. Analyses of 16S rRNA gene libraries showed that bacterial groups from two reactors evolved differently and an overgrowth of protozoa was observed in the bioaugmented BAR Therefore, phage infection and poor biofilm forming ability of the inoculated strain are the main reasons for bioaugmentation failure. In addition, gazing by protozoa of the bacteria might be the reason for the nitrification breakdown in bioaugmented BAF during day 9-18.