Coral Sr/Ca records from Bonaire Holocene corals

Proxy reconstructions of tropical Atlantic sea surface temperature (SST) that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability. Here we present monthly-resolved records of Sr/Ca (a proxy of SST) from fossil annually-banded Diploria strigosa corals from Bonaire (southern Caribbean Sea). The individual corals provide time-windows of up to 68 years length, and the total number of 295 years of record allows for assessing the natural range of seasonal to multidecadal SST variability in the western tropical Atlantic during snapshots of the mid- to late Holocene. Comparable to modern climate, the coral Sr/Ca records reveal that mid- to late Holocene SST was characterised by clear seasonal cycles, persistent quasi-biennial and prominent interannual as well as inter- to multidecadal-scale variability. However, the magnitude of SST variations on these timescales has varied over the last 6.2 ka. The coral records show increased seasonality during the mid-Holocene consistent with climate model simulations indicating that southern Caribbean SST seasonality is induced by insolation changes on orbital timescales, whereas internal dynamics of the climate system play an important role on shorter timescales. Interannual SST variability is linked to ocean-atmosphere interactions of Atlantic and Pacific origin. Pronounced interannual variability in the western tropical Atlantic is indicated by a 2.35 ka coral, possibly related to a strengthening of the variability of the El Niño/Southern Oscillation throughout the Holocene. Prominent inter- to multidecadal SST variability is evident in the coral records and slightly more pronounced in the mid-Holocene. We finally argue that our coral data provide a target for studying Holocene climate variability on seasonal and interannual to multidecadal timescales, when using further numerical models and high-resolution proxy data.

从细胞色素b基因序列变异分析中国鲇形目鱼类的系统发育

采用PCR技术获得中国鲇形目鱼类 1 1科 2 4属 2 7个代表种类细胞色素b基因 1 1 3 8bp全序列 ,比较分析了来自北美洲、非洲的部分鲇形目鱼类同一基因序列 ,并选取脂鲤目、鲤形目和鲱形目鱼类作外类群 ,采用Bayesian方法和最大简约法 (MP)构建分子系统树。结果表明 :(1 )鲇形目鱼类细胞色素b基因序列中 ,与脂鲤目、鲤形目以及鲱形目鱼类相比存在 3bp的缺失 ;(2 )鲇形目鱼类各科代表种类形成一单系群 ;(3 )两种建树方法均支持科、粒鲇科和钝头科形成一单系群 ;而胡子鲇科、

Estabelecimento de estirpes de Bradyrhizobium japonicum/ B.elkanii e seus efeitos na reinoculacao da soja em solos de cerrado.

Neste trabalho sao apresentados os resultados de um estudo para avaliar o estabelecimento de estirpes de Bradyrhizobium japonicum / B. elkanii, na resposta da soja a reinoculacao em solos de Cerrado. O experimento, que teve duracao de seis anos, foi iniciado em 1994 num Latossolo Vermelho de primeiro cultivo, isento de populacoes de rizobio capazes de nodular a soja. O delineamento experimental foi o de blocos ao acaso com tres repeticoes e a cultivar de soja utilizada foi a Doko RC. A ocupacao dos nodulos foi avaliada por tecnicas de imuno-aglutinacao. No primeiro ano do experimento (safra 1993/1994), as estirpes CPAC 7, CPAC 15, 29W e SEMIA 587 (sorogrupos CB1809, SEMIA 566, 29W e SEMIA 587, respectivamente) foram introduzidas no solo por meio da inoculacao das sementes da soja Doko RC. Tambem foi incluido um tratamento sem inoculacao, com as parcelas cultivadas com arroz. No ano seguinte (safra 1994/1995), as parcelas foram subdivididas em tres subparcelas, e a soja foi cultivada sob tres tratamentos: a) CPAC 7, b) CPAC 15 e c) sem inoculacao. No terceiro ano (safra 1995/1996), todo o experimento recebeu a soja inoculada com a estirpe CPAC 7. No quarto e no quinto anos de conducao do experimento (safras 1997/1998 e 1998/1999), a soja foi cultivada sem inoculacao. No ano agricola 1996/1997 a area foi deixada em repouso. Para os tratamentos com inoculacao foram utilizados inoculantes turfosos (8,0 x 108 celulas/g) na proporcao de 1 kg de inoculante por 50 kg de sementes. As estirpes introduzidas no solo no primeiro ano influenciaram a ocorrencia da estirpe CPAC 7 nos nodulos obtidos no terceiro ano de conducao do experimento. Nos tratamentos onde a CPAC 7 foi introduzida no primeiro ano, sua ocorrencia nos nodulos foi, em media, de 70%, enquanto nos outros tratamentos variou entre 25% e 44%. No quarto e quinto anos, quando a soja foi cultivada sem inoculacao, estirpes do sorogrupo SEMIA 566 predominaram na nodulacao (mais de 44% dos nodulos). No quinto ano do experimento, mesmo nos tratamentos onde essa estirpe jamais foi inoculada, a ocorrencia do sorogrupo SEMIA 566 foi de 74% dos nodulos, evidenciando sua elevada capacidade competitiva. Futuras estrategias para reinoculacao da soja em solos de Cerrado com as estirpes CPAC 7 e CPAC 15 deverao levar as observacoes desse estudo em consideracao.

The structure of the copper(II) complex with 4,5-dichlorophthalic acid: The 1:1 complex 'adduct' salt trans-tetraaqua(2-carboxy-4,5-dichlorobenzoato)(4,5-dichlorobenzene-1,2-dicarboxylic acid)copper(II) 2-carboxy-4,5-dichlorobenzoate

The unusual (1:1) complex ‘adduct’ salt of copper(II) with 4,5-dichlorophthalic acid (H2DCPA), having formula [Cu(H2O)4(C8H3Cl2O4) (C8H4Cl2O4)] . (C8H3Cl2O4) has been synthesized and characterized using single-crystal X-ray diffraction. Crystals are monoclinic, space group P21/c, with Z = 4 in a cell with dimensions a = 20.1376(7), b =12.8408(4) c = 12.1910(4) Å, β = 105.509(4)o. The complex is based on discrete tetragonally distorted octahedral [CuO6] coordination centres with the four water ligands occupying the square planar sites [Cu-O, 1.962(4)-1.987(4) Å] and the monodentate carboxyl-O donors of two DCPA ligand species in the axial sites. The first of these bonds [Cu-O, 2.341(4) Å] is with an oxygen of a HDCPA monoanion, the second with an oxygen of a H2DCPA acid species [Cu-O, 2.418(4) Å]. The un-coordinated ‘adduct’ molecule is a HDCPA counter anion which is strongly hydrogen-bonded to the coordinated H2DCPA ligand [O… O, 2.503(6) Å] while a number of peripheral intra- and intermolecular hydrogen-bonding interactions give a two-dimensional network structure.

Structure of disocium uridine 5'-Phosphate heptahydrate

Na2[CgHllN2OgP].7H20, M r = 494.0,orthorhombic, C222~, a = 22.880 (7), b = 8.877 (3),c = 19.592 (9) A, Z = 8, V = 3979.2 A 3. The Cu Ka intensity data consisted of 1005 unique reflections. Final R -- 14.5%. This nucleotide shows no unusual conformational features. The uracil base has an anti conformation about the glycosidic bond (tpo o = 44.4°). The furanose ring conformation is C(2')-endo,gauchegauche with tpo o = -75.5 ° and ~Poc = 49"6°.

Reactions of oxygen containing ligands in the coordination sphere of permethylhafnocene and permethyltantalocene

A series of terl-butylperoxide complexes of hafnium, Cp*₂Hf(R)(OOCMe₃) (Cp* = ((η⁵-C₅Me₅); R = Cl, H, CH₃, CH₂CH₃, CH₂CH₂CH₃, CH₂CH₂CH₂CH₃, CH₂CHMe₂, CH=CHCMe₃, C₆H₅, meta-C₆H₃(CH₂)2) and Cp*(η⁵-C₅(CH₃)₄CH₂CH₂CH₂)Hf(OOCMe₃), has been synthesized. One example has been structurally characterized, Cp*₂Hf(OOCMe₃)CH₂CH₃ crystallizes in space group P2₁/c, with a = 19.890(7)Å, b = 8.746(4)Å, c = 17.532(6)Å, β = 124.987(24)°, V = 2498(2)ų, Z = 4 and R_F = 0.054 (2222 reflections, I > 0). Despite the coordinative unsaturation of the hafnium center, the terl-butylperoxide ligand is coordinated in a mono-dentate ligand. The mode of decomposition of these species is highly dependent on the substituent R. For R = H, CH₂CH₃, CH₂CH₂CH₃, CH₂CH₂CH₂CH₃, CH₂CHMe₂ a clean first order conversion to Cp*₂Hf(OCMe₃)(OR) is observed (for R CH₂CH₃, ΔHǂ = 19.6 kcal•mol^-1, ΔSǂ = -13 e.u.). These results are discussed in terms of a two step mechanism involving η²-coordination of the terl-butylperoxide ligand. Homolytic O-O bond cleavage is observed upon heating of Cp*₂Hf(OOCMe₃) R (R = C₆H₆, meta-C₆H₃(CH₃)₂). In the presence of excess 9,10-dihydroanthracene thermolysis of Cp*₂Hf(OOCMe₃)C₆H₆ cleanly affords Cp*₂Hf(C₆H₆)OH and HOCMe₃ (ΔHǂ = 22.6 kcal•mol^-1, ΔSǂ = -9 e.u.). The O-O bond strength in these complexes is thus estimated to be 22 kcal•mol^-1.

Cp*₂Ta(CH₂)H, Cp*₂Ta(CHC₆H₅)H, Cp*₂Ta(C₆H₄)H, Cp*₂Ta(CH₂=CH₂)H and Cp*₂Ta(CH₂=CHMe)H react, presumably through Cp*₂Ta-R intermediates, with H₂O to give Cp*₂Ta(O)H and alkane. Cp*₂Ta(O)H was structurally characterized: space group P2₁/n, a= 13.073(3)Å, b = 19.337(4)Å, c = 16.002(3)Å, β = 108.66(2)°, V = 3832(1)ų, Z = 8 and R_F = 0.0672 (6730 reflections). Reaction of terlbutylhydroperoxide with these same starting materials ultimately yields Cp*₂Ta(O)R and HOCMe₃. Cp*₂Ta(CH₂=CHR)OH species are proposed as intermediates in the olefin hydride reactions. Cp*₂Ta(O₂)R species can be generated from the reaction of the same starting materials and O₂. Lewis acids have been shown to promote oxygen insertion in these complexes.

Efeito crônico da administração de esteróide anabólico androgênico na próstata de ratos

Esteróides anabólicos androgênicos (EAA) são usados por atletas profissionais e amadores, com o objetivo de melhorar a capacidade atlética, aparência e massa muscular. Muitos efeitos adversos têm sido associados com o abuso de EAA, incluindo doenças do trato urogenital. Este estudo teve como objetivo avaliar as alterações morfológicas no lobo ventral da próstata de ratos púberes e adultos cronicamente tratados com doses suprafisiológicas de EAA, usando métodos morfométricos. Foram estudados 39 ratos Wistar machos pesando entre 400 e 550 g. Os ratos foram divididos em quatro grupos: (a) ratos controle, com 105 dias de idade (C105) (n = 7); (b) ratos controle com 65 dias de idade (C 65) (n = 9), injectados com o veículo (óleo de amendoim); (c) ratos tratados com 105 dias de idade (T105) (n = 10) e (d) Os ratos tratados com 65 dias de idade (C 65) (n = 13). Os ratos tratados foram injectados com decanoato de nandrolona, numa dose de 10 mg.Kg-1 de peso corporal. O hormônio esteróide e o veículo foram administrados por via intramuscular, uma vez por semana, durante oito semanas. Os ratos foram sacrificados aos 161 dias de idade (C105 e T105) e 121 dias de idade (C65 e T65) e do lóbulo ventral da próstata foi dissecada e processada para histologia. A altura do epitélio acinar foi medida em micrômetros em fotomicrografias com ampliação de 400x. As densidades de superfície do lúmen do epitélio e estroma foram calculadas pelo método de contagem de pontos, com uma grade de 100 pontos sobrepostos sobre imagens ampliadas em 200x. Todas as análises foram realizadas com o software ImageJ. O teste t de Student e ANOVA foram utilizados para a comparação de médias. Foi considerado significativo quando p<0,05. O peso e volume do lobo ventral da próstata mostraram diferenças entre os grupos C65, T65, C105 e T105. A altura do epitélio não mostrou nenhuma diferença entre os grupos C65 e T65 (p = 0,8509), mas o grupo T105 mostrou um aumento de 32% em relação ao C105 (p = 0,0089). No que diz respeito à densidade de superfície do lúmen não houve diferença entre C65 e T65 (p = 0,9031) mas uma diminuição de 19% em relação a T105 em comparação com C105 (p = 0,0061). Não houve diferença na densidade de superfície do epitélio entre C65 e T65 (p = 0,7375), mas o grupo T105 apresentou 51% de aumento (p = 0,0065) em comparação com o C105. Em relação à densidade superficial do estroma, não foram observadas diferenças entre C65 e T65 e entre C105 e T105. Finalmente, não houve diferença no padrão de colágeno entre C105 e T105, mas o grupo T65 mostrou uma predominância de fibras de colágeno tipo I em relação ao C65. A utilização de esteróides androgênicos anabólicos em ratos promove mudanças estruturais na próstata. Observamos mudanças estruturais na altura, volume e epitélio do lobo da ventral da próstata e uma predominância de fibras de colágeno.

抚仙湖无机污染物化学背景值及动物体内致突变性评定

为了比较抚仙湖不同区域的水质及其致突变性, 从抚仙湖周围水域采取7 个样点的水样。用电感 耦合氩等离子发射光谱法对水样中的无机污染物作定性和定量分析。另外使用蝌蚪( B uf o buf o andrewsi) 红细 胞微核试验检测抚仙湖水样的致突变性。结果显示: 禄冲采样点水样带有微核的红细胞率增高, 表明这个点水 样有致突变活性物质。

银鲫不同雌核发育系的生物学特性比较研究

银鲫不同雌核发育系间,以D系银鲫体型最高,其相对体高平均为47％,A系为44.4％,C系为43.7％,B系为41.7％。在生长速度方面以D系生长最快,其次为A系,这两个系的银鲫在含肉量与肌肉蛋白质含量上均无明显差异,但D系银鲫对饵料的利用效率明显高于A系,因此生产上养殖以D系银鲫为母本,红鲤为父本人工繁殖而成的高体型异育银鲫,可提高经济效益10—20％。银鲫4个雌核发育系的卵巢发育进程不同,D系卵母细胞在2月份有个迅速发育期,因而最早进入成熟产卵期。A系成熟产卵期略晚,C系成熟产卵期较迟。银鲫染色体数目存

Electronic structures of wurtzite ZnO and ZnO/MgZnO quantum well

The band structures of wurtzite ZnO are calculated using the empirical pseudopotential method (EPM). The 8 parameters of the Zn and O atom pesudopotential form factors with Schluter's formula are obtained. The effective mass parameters are extracted by using k.p Hamiltonian to fit the EPM results. The calculated band edge energies (E-g, E-A, E-B, and E-C) at Gamma point are in good agreement with experimental results. The ordering of ZnO at the top of valence band is found to be A(Gamma(7))-B(Gamma(9))-C(Gamma(7)) due to a negative spin-orbit (SO) splitting. Based on the band parameters obtained, the valence hole subbands of wurzite ZnO/MgxZn1-xO tensile-strained quantum wells (QWs) with different well widths and Mg compositions are calculated using 6-band k.p method. (c) 2005 Elsevier B.V. All rights reserved.

Electronic structures of wurtzite ZnO and ZnO/MgZnO quantum well

The band structures of wurtzite ZnO are calculated using the empirical pseudopotential method (EPM). The 8 parameters of the Zn and O atom pesudopotential form factors with Schluter's formula are obtained. The effective mass parameters are extracted by using k.p Hamiltonian to fit the EPM results. The calculated band edge energies (E-g, E-A, E-B, and E-C) at Gamma point are in good agreement with experimental results. The ordering of ZnO at the top of valence band is found to be A(Gamma(7))-B(Gamma(9))-C(Gamma(7)) due to a negative spin-orbit (SO) splitting. Based on the band parameters obtained, the valence hole subbands of wurzite ZnO/MgxZn1-xO tensile-strained quantum wells (QWs) with different well widths and Mg compositions are calculated using 6-band k.p method. (c) 2005 Elsevier B.V. All rights reserved.

高灵敏显色反应的研究

本论文“高灵敏显色反应的研究”包括五部分：（一）文献综述，对分光光度法测定钨、钼方面的文献作了较为全面的评述，并同其它仪器方法进行了比较。（二）钨的高灵敏显色反应的研究和（三）、钼的高灵敏显色反应的研究：提出了灵敏，简便，快速，稳定的测定钨和钼的方法。在动物胶存在下，在盐酸介质中以氯化亚锡作还原剂，使硫氰酸钨（V）或钼（V）与罗丹明B形成离子缔合物，在水相中直接比色测定钨或钼。本法测钨的表现摩尔吸光系数达9.2*10~5升·摩尔~(-1)·厘米~(1)。0.3-2.0微克钨／50毫升符合部伯－比耳定律。测钼的表现摩尔吸光系数达7.5*10~5升·摩尔~(-1)·厘米~(1)，0.2-2.0微克钼／50毫升符合部伯－比耳定律。本法是目前分光光度法测钨和钼的高灵敏方法之一，用于测定天然水中的痕量钨和钼以及高温合金钢中的钨，获得满意结果。（四）罗丹明B聚合状态及解聚的研究。研究了罗丹明B在不同介质中的聚合状态及解聚效应。结果表明，在电解质溶液中，会促使染料发生聚合；在有机溶剂和一表面活性剂中会促使染料解聚。同时，对染料的聚合及解聚的作用机理进行了初探。（五）离子缔合物增敏剂的研究－动物胶对Mo(V)-SCN~--RhB(I)三元络合物的增敏作用。以Mo(V)-SCN~--RhB(I)三元络合物为例研究了表面活性剂对体系的作用；用平衡移动法初步确定了络合物的组成（Mo:SCN~-:RhB)比为1:10:7；证实了罗丹明B－硫氰酸盐缔合物对形成硫氰酸铜（V）－罗丹明B缔合物的作用。间接证明了这种高配位缔合物是在形成[MoO(SCN)_5]·[RhB]_2缔合物分子时，又吸附了一定量的[RhB]·[SCN]缔合物分子形成的。并讨论了动物胶的增敏作用。另外，通过对碱性染料－金属硫氰酸离子缔合物体系在水相中稳定性的比较，认为这类体系的稳定性主要是由其本身的结构特性所决定的，而表面活性剂只起延长体系稳定时间的作用。

稀土铁双核配合物的合成

本文通过LnCl_3·nTHF和[C_5H_4(SiMe_3)]Na反应得到了两类配合物[C_5H_4(SiMe_3)] LnCl_2·nTHF (Ln = Nd，Sm，Gd；n = 0，1，2)、[C_5H_4(SiMe_3)] LnCl_2·HCl·nTHF (Ln = Nd，Sm，Gd；n = 1，2)。通过元素分析、红外分析、质谱、核磁共振和热重分析确定了配合物的分子组成，特别是带氯化氢的产品在红外光谱中有1250 cm~(-1)，835 cm~(-1)，748 cm~(-1)自的三甲基硅基特征吸收峰。对氯化稀上进行了结构分析，结果发现LnCl_3·4THF (Ln = Sm，Gd)是与NdCl_3·4THF之间存在着变态关系。GdCl_3·4THF。晶体属单斜晶系，空间群为P21/C，晶胞参数为a = 30.765(7)，b = 8.219(3)，C = 17.534(3)A~·，β = 93.71(2)°；SmCl_3·4THF。晶体属单斜晶系，空间群为P21/C，晶胞参数为a = 30.921(13)，b = 8.287(7)，C = 17.665(8)，β = 94.17(4)°。LnCl_3·4THF的单位晶胞中存在着八个分子，每对分子互相等同，但每对分子内部两个分子之间互不等同。SmCl_3·2THF·DME晶体属单斜晶系，空间群为P21/a，晶胞参数为a = 13.547(8)，b = 8.607(4)，C = 16.029(9)A°，β = 90.53(5)°。铲原子与三个氯原子。两个四氢呋喃中的氧原子以及DME中的两个氧原子键合，形成七配位的配合物，但是配位多面体不是理想的五角双锥，而是形成了比五角双锥(D_(5h))对称性更低的多面体(C_(3v))。它能看作是在正八面体的一个面的中心加上第七个原子的结果，而且这八面体主要受到决定上述那个面的三个原子伸展开的畸变。在制备C_5H_5SiMe_3时，如果不用减压蒸馏，而在常压下直接蒸馏，则得到的不是C_5H_5SiMe_3而是它的二聚体(C_5H_5SiMe_3)_2。用红外光谱和核磁共振确定了它的组成和结构，特别是在1650 cm~(-1)处出现(C_5H_5SiMe_3)_2的孤立双键吸收峰。用C_5H_5SiMe_3和Ee(CO)_5回流反应制得了[C_5H_4(SiMe_3) Ee(CO)_2]_2。经过元素分析，红外光谱，质谱，顺磁共振确定了配合物的组成，红外光谱中有桥羰基的吸收峰，质谱图中498的离子峰的出现标志着上述二聚体的存在。用[C_5H_5Fe(CO)_2]_2作为制备双金属配合物的原料，用Na/Hg并还原[C_5H_5Fe(CO)_2]_2。反应时间为6-7小时得到中间体[C_5H_5Fe(CO)_2]_2Na·4THF的深紫红色晶体。反应时间加长，中间体被破坏，反应到15小时时生成了[C_5H_5Fe(CO)_2]Na·TMEDA的黄色晶体，特别是中间体的获得及晶体结构的测定对我们解释反应的机理非常重要。[C_5H_5Fe(CO)_2]_2Na·4THF为单斜晶系，空间群为P21/n，晶胞参数为a = 10.155(5)，b = 17.121(4)，C = 18.667(6)A°，β = 97.61(3)°，V = 3216.9A°~3， 2 = 4。铁的配位数为七，钠的配位数为六，钠离子和桥连羰基氧以配位键结合，每个钠离子连结着两个[C_5H_5Fe(CO)_2]_2~-，而每个[C_5H_5Fe(CO)_2]_2~-又连结着两个钠离子，组成一个无限链状分子，键状分子间以Van de W力结合。[C_5H_5Fe(CO)_2]Na·TMEDA正交晶系，空间群为P_(2,2,2,)。晶胞参数为a = 6.001(4)，b = 10.644(6)，C = 24.214(11)A~·。α = β = r = 90°。z = 4 V = 1546·7A°~3，铁的配位数为五。钠的配位数为四，钠离子和羰基氧以配位键结合，每个钠离子连结着两个[C_5H_5Fe(CO)_2]~-，每个[C_5H_5Fe(CO)_2]~-又连结着两个钠离子，体系就是以这种连结方式或正负电荷交替的形式无限螺旋分子，每个链节存在着两个[C_5H_5Fe(CO)_2]Na·TMEDA分子，链节的长度为a轴的轴长，说明螺旋分子以a轴轴长向上平移。用LnCl_3·nTHF和[C_5H_5Fe(CO)_2]Na反应制得了[C_5H_5Fe(CO)_2] LnCl_2·nTHF (Ln = Nd, Sm, Gd; n = 1, 2)，用[C_5H_5Fe(CO)_2] LnCl_2和[C_5H_4(SiMe_3)]Na或用[C_5H-4(SiMe_3)] LnCl_2和[C_5H_5Fe(CO)_2]Na得到[C_5H_5Fe(CO)_2] [C_5H_4(SiMe_3)] LnCl·nTHF (Ln = Nd, Sm, Gd; n = 0, 1, 3)，配合物[C_5H_5Fe(CO)_2] LnCl_2·nTHF及[C_5H_5Fe(CO)_2] [C_5H_4(SiMe_3)] LnCl·nTHF中存在着2000 cm~(-1)左右的终端羰基吸收峰及1766 cm~(-1)左右的桥连羰基吸收峰。说明稀土和铁之间是以羰基相连的。在TOTOE质谱仪上，配合物[C_5H_5Fe(CO)_2]Gd~·Cl·THF出现[C_5H_5Fe(CO)]GdCl_2、[Fe(CO)_2] Gd~+Cl_2的离子峰，配合物[C_5H_5Fe(CO)_2]-[C_5H_4(SiMe_3)] GdCl·THF出现[C_5H_5Fe(CO)_2] [C_5H_4]Gd~+Cl、[C_5H_5Fe(CO)_2]Gd~+Cl·[C_5H_4C(SiMe_3)] Gd~+Cl等离子峰。所有稀土有机配合物都溶于四氢呋喃、苯，对空气和水敏感。

环戊二烯基轻稀土氯化物的合成及其稳定性的研究

I LnCl_3-LiCl-THF配合物的研究深入地研究了氯化稀土和氯化锂于四氢呋喃溶液中，以不同的摩尔比，在不同条件下的反应。实验结果表明，反应速度随着稀土元素原子半径的减小，LiCl/LnCl_3摩尔比的增大，以及四氢呋喃用量的增加而加快。通过紫外质谱元素分析和X-射线单晶结构分析等证明，随着不同的LiCl/LnCl_3摩尔比和结晶条件的不同，可以得到不同组成的LnCl_3-LiCl-TNF配合物。对(LaCl)(THF)_2(μ_2-Cl)_4[Li(THF)_2]_2和(LaCl)DME(μ_3-Cl)(μ_2-Cl)_5(La·DME)Li(THF)_2晶体的结构分析表明，前者为单斜晶系，P21/C空间群。a=10.542(4), b=32.236(4), c=11.182(6)A °; β=113.50(3) °, V=3484.97 A °~3. Z=4, R=0.0471；后者为三斜晶系，PT空间群，晶胞参数是：a=11.123(3), b=16.564(5), c=8.653(3)A °;α=95.16(3), β=95.63(3), γ=74.71(3) °;V=1527.0A °~3。Z=2，R=0.0303。实验结果还表明，μ_2-和μ_3-氯桥键是LnCl_3-LiCl-THF类配合物中最基本、最重要的配位键，这种键是通过多重键的方式起着稳定分子结构的作用。当进行与有机配体的交换反应时，由于它们的特殊稳定性，能起到阻止轻稀土有机配合物歧化反应的作用。II环戊二烯基轻镧系氯化物的合成及其稳定性的研究对(G_5H_5)_3Ln·THF和LnCl_3·3LiCl-THF (Ln=La, Nd)溶液反应的研究表明，由于μ_2-氯桥键的作用，轻稀土环戊二烯基化合物中环戊二烯基的再分配反应，在0℃或室温下都能迅速进行。通过两者不同的摩尔比反应，经元素分析、红外光谱、~1H NMR和质谱鉴定，方便地合成了C_5H_5 LnCl_2·2LiCl·5THF和(C_5H_5)_2LnCl.LiCl·nTHF (Ln=La, Nd)等配合物。这一结果表明(C_5H_5)_2LnCl.LiCl·nTHF配合物不仅能稳定地存在于THF溶液中，而且能在一定条件下析出结晶。对(C_5H_5)_2LaCl.LiCl·4THF的晶体结构测定表明，该晶体属于正交晶系，Pc2m空间群。a=12.306(4), b=23.056(6), c=26.701(11)A°; V=7575.81A°~3;而(C_5H_5)_2LaCl·LiCl(DME)_2THF晶体则属于六方晶系，a=12.967(4), b=12.967(4), c=24.108(10)A°;V=3510 A°~3。通过(G_5H_5)_3Ln·THF与LnCl_3·3THF (Ln=La, Nd)的反应进一步研究了轻稀土环戊二烯基氯化物的稳定性。经元素分析，红外光谱和晶体结构分析表明合成了[(η~5-C_5H_5)_4La_3Cl_5·3THF]_2·9THF和(C_5H_5)_2 NdCl·THF配合物，前者属于三斜晶系，P1空间群。a=11.690(3), b=11.750(5), c=18.433(6)A°; α=98.75(3), β=95.62(3), γ=118.92(2)°; V=2147.06 A°~3. Z=1, R=0.099。对环戊二烯基轻稀土氯化物的稳定性进行了较详细地讨论。结果表明，THF的用量和化合物的溶解度是影响产物组成的决定因素。当THF的量不足以溶解所生成的产物时，就会歧化成溶解度最大((C_5H_5)_3Ln·THF)和最小(LnCl_3·nTHF)的两种组分。反之，环戊二烯基轻稀土化合物(Ln=La, Nd)中环戊二烯基的再分配反应就能顺利进行。经元素分析和结构测定，在((C_5H_5)_3Nd·THF)和NdCl_3·LiCl-THF溶液的反应体系中，偶然分离得到了[(η~5-C_5H_5)_4Nd_4(μ_4-o)(μ_2-Cl)_8] [Li(DMP)_2THF]_2这一不合常规的化合物，其晶体属于正交晶系，Pna2,空间群a=19.010(7), b=23.231(6), c=14.180(4); V=6261.91 A°~3。Z=4, R=0.054。说明在一定条件下,μ-氧桥键也起到了稳定分子结构的作用。推测了各类环戊二烯基轻稀土氯化物在THF中的合成反应机理,在LiCl存在的反应体系中Ln cl cl Li桥键能与环戊二烯基发生交换反应;在(C_5H_5)_3Ln·THF和LnCl_3·3THF的反应体系中,首先存在着LnCl_3分子之间的互相作用，因而易于形成双核或多核配合物。这类配合物以晶体形式析出时，易于发生结构上的变化，即化合物的结晶形态与溶液中的形态不一定相同。探索了环戊二烯基烯丙基稀土化合物新的合成方法。找到了真空加热脱水制备氯化稀土的最佳条件，其产物纯度在97%以上。通过加入Co_3O_4/Wo_3催化助燃剂的方法，提高了测定稀土有机化合物中碳含量的准确性。

气候变化对东北森林主要建群种潜在分布的影响

在过去近百年全球气候迅速变暖的过程中，中国东北地区的气候变化幅度更显突出。各种大气环流模型的预测结果表明，该区在未来百年内的升温将更加急剧。东北地区的森林在过去的百年内已经遭受了气候变暖、自然和人类干扰的三重压力，森林的质量已经急剧下降，数量也大大减少。未来剧烈的气候变化将会对它产生怎样的影响无疑是人们所关注的热点。 本文以整个东北地区的森林为研究对象，以景观生态学原理为基础，结合地理信息系统以及多种数学方法和统计模型，分析过去40年以及未来100年的气候变化特点和趋势，探讨了东北地区目前的森林植被与环境因子的数量关系，探讨了未来气候变化对东北森林建群种以及目前占优势的落叶松属树种潜在分布的影响。以此为东北地区的生态环境保护、林业的持续发展提供一些基础信息。 通过本论文的相关研究，得出以下主要结论： （1）在过去40年中，区域的气候朝温暖和干旱化方向发展。1966-1970是最为寒冷的5年，而1969年是最寒冷的年份；2001-2003是最为炎热的3年。降水的变化具有以下的规律：南部的多雨期出现的比北部早，东部的多雨期比西部的早。而在未来100年，东北的气温会持续上升，2050年气温平均上升2.7℃左右，2100年达到6℃左右。升温具有如下特点：南部增温幅度比北部小，东部的增温幅度比西部小。降水的变化在整体上没有明显的规律，2050年，东部和西部的降水减少，而北部和南部则增加；2100年，东部、东北部和南部的降水减少，而西部的降水增加。 （2）用典范对应分析对目前的植被与环境因子的数量关系进行研究，同时检验了样方大小以及样带的走向对排序结果的影响。结果表明： 在区域尺度上，沿小兴安岭走向设置的样带1是一条海拔和温度的综合梯度带，样带的东南部气温较高，海拔较低，西北部正好相反。寒温带针叶林（兴安落叶松等）分布于样带西北部，温带针阔叶混交林（红松等）分布于东南部。 沿大兴安岭走向设置的样带2是一条降水、温度和海拔的综合梯度带，样带西南部的降水较多，气温较高，海拔也较高，而东北部的环境条件则相反。寒温带针叶林（兴安落叶松林、樟子松林等）分布样带东北部，温带针叶林（油松等）落叶阔叶林（榆树疏林等）分布于海拔较高的样带西南部。 沿长白山脉走向设置的样带3森林类型最为丰富，体现了海拔和温度的综合梯度，海拔梯度的方向与样带走向近于垂直，样带西南部的温度较高。寒温带针叶林（臭冷杉林、鱼鳞云杉林等）分布于样带北部；温带针叶林（油松、赤松等）和阔叶林（辽东栎林、麻栎林等）分布于样带南部。 在景观尺度上，设置于呼中自然保护区的样带是一条海拔、温度和降水的综合样带；设置于丰林自然保护区的样带1是一条海拔和坡度的样带。大尺度上的排序分析有利于我们从整体上把握植被和环境因子之间的数量关系，但是也存在一些问题。例如，样方的大小和样带的走向都会影响到排序的结果。双序图中的物种在环境梯度上的位置是相对的，需要和该样方具体的环境值域结合起来解释物种的环境分布。同一条样带以不同的方式取样时，狭布种的排序结果会发生变化，而广布种的排序的结果变化不大。 （3）在考虑2个气候因子、3个地形因子和6个土壤因子的基础上，用logistic回归模型，模拟预测三种气候变化方案-HADCM2SUL、CGCM1和CGCM2-对东北森林建群种未来潜在空间分布的影响。 （a）HADCM2SUL方案: 气温上升3.5℃，降水增加30.7%； （b）CGCM1方案: 气温上升5.2℃，降水增加25.1%， （c）CGCM2方案: 气温上升3.33~7.17℃，降水变幅-66~115mm， 本文所采用的HADCM2SUL和CGCM1气候变化方案是它们的全球平均值。而CGCM2是针对中国东北地区的，具有空间异质性的气候变化方案。结果表明，除了山杨的潜在分布不受影响之外，其他建群种受气候变暖的影响的方向以及程度依气候变暖方案的不同而不同： HADCM2SUL方案下，兴安落叶松潜在分布面积急剧减少，云杉、冷杉和白桦开始减少，红松、长白落叶松和蒙古栎增加。 CGCM1方案下，兴安落叶松几乎消失，云冷杉急剧减少、白桦，红松减少、长白落叶松和蒙古栎仍然增加。 CGCM2方案下，兴安落叶松、云冷杉和红松完全消失，长白落叶松大量减少，蒙古栎和白桦的存在概率减少。 （4）在考虑2个气候因子和3个地形因子的基础上，用权重证据法（Weight Of Evidence，WOE）和logistic回归模型，对落叶松属三个树种的潜在分布研究表明，兴安落叶松的生境是三者之中最为寒冷和干旱的，长白落叶松倾向于温暖湿润的环境，华北落叶松则趋向于温暖以及较干旱的环境。CGCM2气候变化方案下，兴安落叶松潜在分布区将完全退出东北；长白落叶松潜在分布区将从目前的长白山地区向北迁移到小兴安岭南部以及张广才岭和老爷岭的大部分地区；而目前位于大兴安岭最南端的华北落叶松则可能迁移到大兴安岭中段的乌兰浩特附近山区。