193 resultados para Wisconsin Infantry. 2d Regiment, 1898. Co. C
Resumo:
Amorphous samples of polyether ketone with cardo(PEK-C) have been studied in the solution state by C-13, H-1 high-resolution NMR, The H-1 and C-13 1D NMR spectra were assigned using two dimensional chemical shift correlated spectroscopy, 2D homonuclear correlated(COSY) and heteronuclear correlated (HETCOR) spectroscopy present important information. In this work, the structural units of PEK-C was determined by NMR. For some peaks, these assignments are confirmed by two dimensional long-range heteronuclear correlation experiments, A little modification is made on the original C-13 peak assignments for the main chain, The symmetry and the isotacticity of the chain structure for PEK-C are obvious on NMR data.
Resumo:
With XRD, R-T, and ac chi measurements a comparative study on the doping effects of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Zn) has been carried out. The effects of the former five members are significantly different, both on phase formed and on T-c, from the latter four. It seems that the effect on phase stabilization correlates with the valency of the doped cation. In connection with the instability of the 2223 phase, the correlation has been discussed.
Resumo:
Ethylene-propene copolymers (EPR) were synthesized at different feed compositions using a highly active and isospecific MgCl2-supported Ti-based catalyst. The thermal behavior of EPR was studied by differential scanning calorimetry, the heterogeneity by f
Resumo:
Reaction of 1,3-cyclohexadiene(tricarbonyl)iron (1) with ortho-substituted aryllithium reagents ArLi (Ar=o-CH3C6H4, o-CH3OC6H4, o-CF3C6H4) in ether at low temperature, and subsequent alkylation of the acylmetalates formed with Et3OBF4 in aqueous solution at 0-degrees-C or in CH2Cl2 at -60-degrees-C gave the 1,3-cyclohexadiene(dicarbonyl)[ethoxy(aryl)carbene]iron complexes (eta4-C6H8)(CO)2FeC(OC2H5)Ar (3, Ar = o-CH3C6H4; 4, Ar = o-CH3OC6H4), and the isomerized product (eta3-C6H8)(CO)2FeC(OC2H5)C6H4CF3-o (5), respectively, among which the structure of 3 has been established by an X-ray diffraction study. Complex 3 is monoclinic, space group P2(1) with a = 8.118(4), b = 7.367(4), c = 14.002(6) angstrom, beta = 104.09(3)-degrees, V = 812.2(6) angstrom3, Z = 2, D(c) = 1.39 g cm-3, R = 0.056, and R(w) = 0.062 for 976 observed reflections. Complexes 3 and 5 were converted into the chelated allyliron phosphine adducts(eta3-C6H8)(CO)2(PR31)FeC(OC2H5)Ar (6, Ar = o-CH3C6H4, R1 = Ph; 7, Ar = o-CH3C6H4, R1 = OPh; 9, Ar = o-CF3C6H4, R1 = Ph), by reaction with phosphines in petroleum ether at low temperatures.
Resumo:
The miscibility of poly(hydroxyether of bisphenol A) (phenoxy) with a series of poly(ethylene oxide-co-propylene oxide) (EPO) has been studied. It was found that the critical copolymer composition for achieving miscibility with phenoxy around 60-degrees-C is about 22 mol % ethylene oxide (EO). Some blends undergo phase separation at elevated temperatures, but there is no maximum in the miscibility window. The mean-field approach has been used to describe this homopolymer/copolymer system. From the miscibility maps and the melting-point depression of the crystallizable component in the blends, the binary interaction energy densities, B(ij), have been calculated for all three pairs. The miscibility of phenoxy with EPO is considered to be caused mainly by the intermolecular hydrogen-bonding interactions between the hydroxyl groups of phenoxy and the ether oxygens of the EO units in the copolymers, while the intramolecular repulsion between EO and propylene oxide units in the copolymers contributes relatively little to the miscibility.
Resumo:
The half-open vanadocene, V[2,4-(CH3)2C5H5](C5H5)CO, was obtained by the reaction of V[2,4-(CH3)2C5H5](C5H5)PMe3 with CO in petroleum ether at room temperature. Its crystal structure was determined by X-ray diffraction technique. The crystal was monoclinic with space group P2(1)/n, a = 16.614(3), b = 7.636(1), c = 19.128(6) angstrom, beta = 99.92(2)-degrees, V = 2390.5(9) angstrom3, and Z = 8. The final R value was 0.043. The V(1)-CPD(1) (half) (PD = 2,4-(CH3)2C5H5) bonds were shorter (0.038 angstrom) than the V(1)-CCP(1) (half) (CP = C5H5) bonds, averaging 2.224(4) versus 2.262(4) angstrom, respectively. 4V[2,4-(CH3)2C5H5](C5H5)CO has been characterized by IR and EPR methods.
Resumo:
Thermally induced phase separation in the mixture of poly (methyl methacrylate) (PMMA) with poly(styrene-co-acrylonitite (SAN) has intern studied with pulsed nuclear magnetic resonance(NMR) in single spin-lattice retaxation time T-1 of the eornpatibl. mixture two T-1 corresponding to those of PM MA-rich and SAN-rich comairis. Meanwhile, both T-1 gradually changing with annealing time provides the direct evidence that the phase separation takes place with a decomposition mechanism. Diffusion coeffieient was to lac negative, indicating an uphal diffusion characteristics, The basic parameters governing its kinetics were estimated using NMR date which were in good agreement with those evaluated from time-resolved light scattering experiments for a 60/40(PMMA/SAN) mixture annealed at 180.0 degrees C.
Resumo:
The phase behaviours of poly(vinyl acetate) (PVAc) and poly(styrene-co-acrylonitrile)s (SAN) with poly(epichlorohydrin) (PECH) were examined using differential scanning calorimetry and an optical method using a hot plate. The PECH/PVAc blends showed LCST behaviour. The observed miscibility is thought to be a result of hydrogen-bonding interactions between the alpha-hydrogen atoms of PECH and the carbonyl groups of PVAc. Two SAN copolymers with an acrylonitrile (AN) content of 18 wt% (SAN18) and 25 wt% (SAN25), respectively, were also found to exhibit miscibility with PECH. No phase separation occurred by heating up to about 280-degrees-C, and the individual blend has a single, composition-dependent glass transition temperature. The formation of miscible PECH/SAN blends can be considered as a result of the intramolecular repulsion between styrene and AN units in SAN.
Resumo:
Four new halogenated nonterpenoid C-15-acetogenins, 4:7,6:13-bisepoxy-9,10-diol-1,12-dibromopentadeca-1,2-diene (1, laurendecumallene A), 4:7,6:12-bisepoxy-9,10-diol-1,13-dibromopentadeca-1,2-diene (2, laurendecumallene 13), (3Z)-6:10,7:13-bisepoxy-12-bromo-9-hydroperoxylpentadeca-3-en-1-yne (3, laurendecumenyne A), and (3Z)-6:10,9:13-bisepoxy-12-bromo-7-chloropentadeca-3-en-1-yne (4, laurendecumenyne 13), together with one known halogenated C-15-acetogenin elatenyne (5) were isolated and identified from the organic extract of the marine red alga Laurencia decumbens. Their structures and relative stereochemistry were established by means of spectroscopic analysis including UV, IR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and ID and 2D NMR techniques. All these metabolites were submitted for the cytotoxic assay against tumor cell line A549 (human lung adenocarcinoma), but all of them were found inactive (IC50 > 10 mu g/mL).
Improving Ship Detection with Polarimetric SAR based on Convolution between Co-polarization Channels
Resumo:
The convolution between co-polarization amplitude only data is studied to improve ship detection performance. The different statistical behaviors of ships and surrounding ocean are characterized a by two-dimensional convolution function (2D-CF) between different polarization channels. The convolution value of the ocean decreases relative to initial data, while that of ships increases. Therefore the contrast of ships to ocean is increased. The opposite variation trend of ocean and ships can distinguish the high intensity ocean clutter from ships' signatures. The new criterion can generally avoid mistaken detection by a constant false alarm rate detector. Our new ship detector is compared with other polarimetric approaches, and the results confirm the robustness of the proposed method.
Resumo:
Stomach contents were examined of 4527 adult individuals of 12 flatfish species collected during the 1982 - 1983 Bohai Sea Fisheries Resources Investigation. Their food habits, diet diversity, similarity of prey taxa, trophic niche breadth and diet overlap were systematically analysed. Ninety-seven prey species belonging to the Coelenterata, Nemertinea, Polychaeta, Mollusca, Crustacea, Echinodermata, Hemichordata and fish were found and five of them were considered to be principal prey for flatfishes: Alpheus japonicus, Oratosquilla oratoria, Alpheus distinguendus, Loligo japonicus and Crangon affinis. Among the flatfishes, Paralichthys olivaceus was piscivorous, whereas Pseodopleuronectes yokohamae and Pseudopleuronectes herzensteini both had polychaetes and molluscs as their main prey groups. Pleuronichthys cornutus was classified as a polychaete-mollusc eater, with a strong preference for crustaceans. Verasper variegatus, Cynoglossus semilaevis, Eopsetta grigorjewi and Cleisthenes herzensteini ate crustaceans. Kareius bicoloratus was classified as a mollusc-crustacean eater: Cynoglossus abbreviatus, Cynoglossus joyneri and Zebrias zebra were grouped as crustacean-fish eaters. However, Z. zebra also took polychaetes and C. abbreviatus and C. joyneri preyed on some molluscs. Trophic relationships among the flatfishes were complicated, but they occupied distinctive microhabitats in different seasons and selected their specific prey items, which was favourable to the stability of the flatfish community in the Bohai Sea.
Resumo:
Suspension aquaculture of filter-feeding bivalves has been developing rapidly in coastal waters in the world, especially in China. Previous studies have demonstrated that dense populations of filter-feeding bivalves in shallow water can produce a large amount of faeces and pseudofaeces (biodeposits) that may lead to negative impacts on the benthic environment. To determine whether the deposit feeder Stichopus (Apostichopus) japonicus Selenka can feed on bivalve biodeposits and whether the sea cucumber can be co-cultured with bivalves in suspended lantern nets, three experiments were conducted, two in tanks in the laboratory and one in the field. In a 3-month flow-through experiment, results showed that sea cucumbers grew well with specific growth rate (SGR) reaching 1.38% d(-1), when cultured in the bottom of tanks (10 m(3) water volume) where scallops were cultured in suspension in lantern nets. Moreover, results of another laboratory experiment demonstrated that sea cucumbers could survive well on bivalve biodeposits, with a feeding rate of 1.82 +/- 0.13 g dry biodeposits ind(-1) d(-1), absorption efficiency of organic matter in biodeposits of 17.2% +/- 5.5%, and average SGR of 1.60% d(-1). Our longer-term field experiments in two coastal bays (Sishili Bay and Jiaozhou Bay, northern China) showed that S. japonicus co-cultured with bivalves also grew well at growth rates (0.09-0.31 g wet weight ind(-1) d(-1)) depending on individual size. The results suggest that bivalve lantern nets can provide a good habitat for sea cucumbers; and the co-culture of bivalve molluscs with sea cucumbers may provide an additional valuable crop with no additional inputs. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
泥炭以发育广泛、连续沉积好、沉积速率大(可达1mm/a甚至更大)、记录丰富等特点,正成为过去全球变化研究的良好综合地质档案.参考冰芯、黄土、深海沉积物等中矿物固体的研究思路和方法,希望能对泥炭中可能存在的火山物质和其它风粉尘进行研究.在对吉林金川西大甸子泥炭样品的处理过程中,摸索出一套泥炭样品中固体物质(如火山物质)初步的处理、分析方法;并对金川西大甸子干玛珥泥炭沉积中部一段泥砂状物质进行鉴定,首次发现火山玻璃,判断这些泥砂物为火山灰砂.目前研究表明,泥炭纤维素的δ<'13>C序列能较好地反映古气候变化,那么泥炭中胡敏酸的δ<'13>C序列可否也能反映古气候变化,该文对此作了初步研究.用碱溶酸沉淀方法从泥炭中提取出所谓的胡敏酸,用燃烧法将胡敏酸、纤维素中的碳转化为CO<,2>气体,测定它们的稳定碳同位素组成(δ<'13>C).与能较好地反映气候变化的纤维素δ<'13>C序列相比,胡敏酸的δ<'13>C序列反映气候变化不明显.
Resumo:
在自然界中存在一套由硅质岩、泥质岩/页岩或板岩、碳酸盐岩和粉砂岩组成的沉积建造,并以富含有机质和菌藻微生物等为特征,沉积厚度较大,岩石类型以硅岩为主,称之为“硅岩建造”。硅岩建造中的硅质岩不仅是许多重要矿种(如金、硒、铀、钒、磷、锰、铂族元素、重晶石和黄铁矿等)的赋存层和含矿岩系的重要岩类,而且由于它形成于特定的地球化学条件下,能够反映出某些沉积相带特殊的地质背景,另外,硅质岩本身就是一种生物岩,对探讨生物成岩、成矿作用有重要意义。所以对硅岩建造及其内硅质岩研究具有十分重要的理论意义和实用价值。因此,本论文选择扬子地块周边寒武系(南秦岭紫阳硒富集区)、二叠系(湖北恩施双河渔塘坝硒矿床)富硒硅岩建造为研究对象。通过岩石地球化学、同位素地球化学、矿物学以及流体包裹体等方法从含硒规律、岩石成因、沉积环境、成矿流体性质等方面,分别对对两个不同时代或不同层位的富硒硅岩建造开展了系统的地球化学对比研究;并从矿物学、包裹体成分及物理化学条件等方面对渔塘坝硒矿床的成因作了探讨。通过研究,取得了以下主要认识:1渔塘坝硒矿区和紫阳硒富集区富硒硅岩建造岩石以硅质岩为主,硅质岩中5102含量范围分别为64.2%-95.84%和63.62%-95.24%。同时包括部分碳质硅质岩丫碳质页岩 和碳、硅板岩及含腐泥层的石煤;渔塘坝硒矿床硅质岩中Se含量大于80ug/g的样品均采自下二叠统茅口组的硅质岩段内,紫阳下寒武统硒富集体中硅质岩中硒的含量最高(可达278ppm)。2微量元素研究表明,两地区富硒硅质岩中均含有较高的Cu,Ni、V、As、Sb、Cr,且U/Th>1。在U-Th、Zr-Cr和P2O5-Y相关图以及Fe-Mn-(Cu+Co+Ni)三角图上,两研究区内硅质岩样品点均落于热水沉积区。渔塘坝硒矿区硅质岩的REE总量较低,平均为38.9×10-6,紫阳硒富集区硅质岩REE总量除个别较高(达110×10-6以上)外,总体也较低(12.0-37.6)×l0-6;另外,从稀土元素配分模式看,两地区硅质岩均有较明显的Ce负异常,且Eu从无明显Eu异常到出现正Eu异常。都反映出热水沉积硅质岩的特征。从si和O同位素组成来看,两个地区硅质岩的δ3051和δ18O值也总体位于热水成因硅质岩区域内。根据隧石一水的氧同位素分馏方程计算得知,两研究区硅质岩的形成温度分别为46℃-72℃和78.6℃-126.20℃。地球化学特征表明,两地区富硒硅质岩均来自热水沉积作用。另外,渔塘坝硒矿区硅质岩中Cr含量较高,且存在腕足类生物化石;紫阳硒富集区硅质岩中Ba及有机质含量较高,且存在叶琳生物标志化合物。结合两地区碳同位素组成特征(渔塘坝地区δ13c为正值,可能和上扬子区早、晚二叠世之间多期次喷发的火山活动,造成地球史上二叠纪生物大灭绝有关;紫阳地区δ13C为负值,说明碳同位素来源于沉积有机物质),暗示两地区硅质岩的成因可能与火山沉积作用有关,且在成岩过程中有部分生物的参与。3渔塘坝赋矿硅质岩硫同位素组成具有较高的负值,表明矿床形成于缺氧的海盆内:紫阳硒富集区形成黄铁矿的硫主要来自海水硫酸盐。4系统研究了渔塘坝硒矿区硒的矿物学,显示硒以自然硒、独立矿物、类质同像及有机吸附四种形式赋存于矿床中。废弃石煤堆中的自然硒矿物,是自然因素和人为活动共同干预的结果,并非石煤的缓慢自燃的结果。5对研究区成矿流体中包裹体均一温度、盐度和密度进行了系统研究,结果显示:两地区的流体包裹体以原生包裹体为主,数量较多且形态复杂;研究区(渔塘坝硒矿和紫阳硒富集区)成矿流体处于中一低温( 190-250)℃和(120-155)℃条件。渔塘坝硒矿区石英和方解石包裹体内的流体盐度分别为(5.9-10.l)B%和(3.9-4.5)WB%,紫阳硒富集区流体盐度为(1.2-2.8)WB%,后者流体盐度明显低于前者。流体密度经计算分别为0.79-0.79/cm3和0.69-0.969/cm3。重点对渔塘坝硒矿区的石英和方解石包裹体进行了拉曼光谱成分测试,结果显示:包裹体成分以H2O和N2为主,含少量 CH4、C2H4、C2H6、C3H5、C4H6、C4H4和C6H6等成分,说明成矿溶液介质主要为具有还原性质的水溶液,其成矿条件具还原性的特点。6渔塘坝硒矿区成矿物理化学条件的研究表明,即富硒成矿流体为中低温(190-250)℃、压力平均为60Mpa。成矿早期02、eZ相对较低,乃较高,且fS2/fSe2>l,有利于硫化物沉淀在成矿主阶段,随着硫化物的沉淀,fS2和fSe2相应增大,且fO2较高。高的fO2阻止了硒进入硫化物,而有利于硒化物的形成。 7系统研究了富硒硅岩建造的沉积环境和构造环境特征,认为渔塘坝硒矿床中富硒硅质岩主要形成于浅海滞留的盆地沉积环境,紫阳下寒武统硅质岩沉积环境属于深水滞留沉积环境;渔塘坝硒矿床主要形成于拉张的断陷盆地中,紫阳硒富集体则形成于拉张的裂谷环境。
Resumo:
Simultaneous NO reduction and CO oxidation in the presence of O-2,H2O and SO2 over Cu/Mg/AUO (Cu-cat), Ce/Mg/Al/O (Ce-cat) and Cu/Ce/Mg/Al/O (CuCe-cat) were studied. At low temperatures (<340 degreesC), the presence of O-2 or H2O enhanced the activity of CuCe-cat for NO and CO conversions, but significantly suppressed the activity of Cu-cat and Ce-cat, At high temperature (720 degreesC), the presence of O-2 or H2O had no adverse effect on the NO and CO conversions over these catalysts. The addition of SO2 to NO + CO + O-2 + H2O system had no effect on the, reaction of CO + O-2 over Cu-cat, but deactivated this catalyst for NO + CO and CO + H2O reactions; over Ce-cat, all of these reactions of NO + CO, CO + O-2 and CO + H2O were suppressed significantly; over CuCe-cat, NO + CO and CO + O-2 reactions were not affected while the reaction of CO + H2O was slightly inhibited. (C) 2002 Elsevier Science B.V. All rights reserved.