双奇核中πi_(13/2)νi_(13/2)2-准粒子转动带旋称反转研究

利用重离子熔合蒸发反应和在束γ谱学实验方法研究了双奇核176,178Ir和182 Au的高自旋态结构 ,在这 3个双奇核中观测到了基于πi13 2 νi13 2 准粒子组态下的转动带 .以能级间隔系统学为判据 ,对184Au核中πi13 2 νi13 2 转动带能级自旋进行了指定 .指出176,178Ir和182 ,184Au 4个双奇核的πi13 2 νi13 2 转动带在低自旋区均出现旋称反转 .对πi13 2 νi13 2 转动带旋称反转现象进行了定性的讨论 .用推转壳模型对πh9 2 νi13 2 带和πi13 2 νi13 2 带能级结构进行了理论研究 ,发现当采用形变和对力自洽计算后 ,从理论上可以定性地解释两个半退耦带出现的旋称反转现象

红松和长白松针叶暗呼吸对连续4个生长季高浓度CO_2处理的响应

以开顶箱法研究了高浓度CO2对长白山两种针叶树—红松和长白松针叶暗呼吸作用的长期影响.对两个树种连续4个生长季进行700和500μmol·mol-1CO2处理,同时设接受大气CO2浓度(约350μmol·mol-1CO2)的开顶箱为对照,在CO2处理的第2,3和4个生长季分别测定了针叶的暗呼吸速率.结果表明:CO2处理的第2个生长季,高浓度CO2下红松和长白松针叶暗呼吸速率增加,可能与碳氮含量变化有关;CO2处理的第3个生长季,高浓度CO2条件下生长的红松针叶暗呼吸速率增加,长白松针叶的暗呼吸速率下降,两树种呈不同响应主要与植株的生长速率不同有关;CO2处理的第4个生长季,红松和长白松针叶的暗呼吸速率均受高浓度CO2抑制.第3个生长季通过改变测量CO2浓度,发现高浓度CO2对长白松针叶暗呼吸作用的短期效应与长期效应呈现一致性,红松不完全相同.红松和长白松针叶的暗呼吸作用对高浓度CO2的响应与CO2处理时间及植株个体的生长发育阶段有关,暗呼吸速率的变化是CO2直接作用与长期驯化共同作用的结果,不能用短期的测定结果预测针叶暗呼吸对高浓度CO2响应的长期效应.

新型二维异核配位聚合物{[NdBi(cydta)(NO_3)_2(H_2O)_4]·2.5H_2O}_n的晶体结构与热分解

由Bi(Hcydta).5H2O和Nd(NO3).6H2O按1︰1的物质的量比,在水溶液中合成了含Bi(III)-Nd(III)的异核配位聚合物{[(NO3)Nd(H2O)4(μ3-cydta)Bi(μ-ONO2)].2.5H2O}n.用元素分析、红外光谱、热重-差热和X射线单晶衍射等手段对标题配合物的组成和结构进行了表征.该配合物属三斜晶系,空间群P1,晶胞参数:a=0.9235(3)nm,b=1.0902(4)nm,c=1.4253(5)nm,α=71.840(4)°,β=86.877(4)°,γ=76.991(4)°,Z=2,Mr=936.65,V=1.3284(8)nm3,Dc=2.342g.cm-3,μ=8.646mm-1,F(000)=900,最终偏离因子R1=0.0406,wR2=0.1124.在该配合物中,铋(III)与配体cydta4-的4O2N和1个硝酸根中1个O原子以及邻位分子的硝酸根形成8配位的畸变双帽三棱柱.钕(III)与4个水分子的O,1个硝酸根中2个O以及来自3个不同配体cydta4-的桥联羧基O结合,形成9配位的三帽三棱柱构型.羧酸根在Bi—Nd和硝酸根在Bi—Bi间的桥联作用...

Thiophene-NPN Ligand Supported Rare-Earth Metal Bis(alkyl) Complexes. Synthesis and Catalysis toward Highly trans-1,4 Selective Polymerization of Butadiene

A series of new rare-earth metal bis(alkyl) complexes [L(1-3)Ln(CH2SiMe3)(2)(THF)(n)] (L-1 = MeC4H2SCH2NC6H4(Ph)(2)P=NC6H2Me3-2,4,6: Ln = Sc, n = 1 (1a); Ln = Lu, n = 1 (1b); L-2 = MeC4H2SCH2NC6H4(Ph)(2)P=NC6H3Et2-2,6: Ln = Sc, n = 1 (2a); Ln = Lu, n = 1 (2b); Ln = Y, n = 1 (2c); L-3 = MeC4H2SCH2NC6H4(Ph)(2)P=(NC6H3Pr2)-Pr-i-2,6: Ln = Sc, n = 0 (3a)) and (LSc)-Sc-4(CH2SiMe3)(2()THF) (4a) (L-4 = C6H5CH2NC6H4(Ph)(2)P=NC6H3Et2-2,6) have been prepared by reaction of rare-earth metal tris(alkyl)s with the corresponding HL1-4 ligands via alkane elimination.

Effect of Single- and co-Dopant on TL of Sr2Mg(BO3)(2) Phosphor

Sr2Mg(BO3)(2) thermoluminescence (TL) phosphor was synthesized by a high temperature solid state reaction and the effect of Li+, Bi3+, Gd3+ or Ti4+ as a codopant on TL of Sr2Mg(BO3)(2) : Dy was investigated. The results show that Li+ as a codopant improves the emission intensity of high temperature TL peak of Sr2Mg(BO3)(2) : Dy phosphor whereas the addition of Bi3+, Gd3+ or Ti3+ leads to the decrease of TL intensity. The TL emission bands of Sr2Mg(BO3)(2) : Dy phosphors with Li+, Bi3+, Gd3+ or Ti4+ as a codopant are situated at 480, 579, 662 and 755 nm, which were attributed to the characteristic F-4(9/2)-> H-6(15/2), F-4(9/2)-> H-6(13/2), F-4(9/2)-> H-6(11/2) and F-4(9/2)-> H-6(9/2) transitions of Dy3+ ion, consistent with the emission of Sr2Mg(BO3)(2) : Dy phosphors. The kinetics parameters of 234 degrees C TL peak of Sr2Mg(BO3)(2) Dy-0.04(3+), (Li-0.04(+)) phosphor with the values of trap depth E=1.1 eV, frequency factor s=6.3 x 10(9) s(-1) were estimated by a peak shape method, which obey the second order kinetics.

Effect of Single- and co-Dopant on TL of Sr2Mg(BO3)(2) Phosphor(单掺杂与共掺杂离子对Sr_2Mg(BO_3)_2磷光体热释发光的影响)

Sr2Mg(BO3)(2) thermoluminescence (TL) phosphor was synthesized by a high temperature solid state reaction and the effect of Li+, Bi3+, Gd3+ or Ti4+ as a codopant on TL of Sr2Mg(BO3)(2) : Dy was investigated. The results show that Li+ as a codopant improves the emission intensity of high temperature TL peak of Sr2Mg(BO3)(2) : Dy phosphor whereas the addition of Bi3+, Gd3+ or Ti3+ leads to the decrease of TL intensity. The TL emission bands of Sr2Mg(BO3)(2) : Dy phosphors with Li+, Bi3+, Gd3+ or Ti4+ as a codopant are situated at 480, 579, 662 and 755 nm, which were attributed to the characteristic F-4(9/2)-> H-6(15/2), F-4(9/2)-> H-6(13/2), F-4(9/2)-> H-6(11/2) and F-4(9/2)-> H-6(9/2) transitions of Dy3+ ion, consistent with the emission of Sr2Mg(BO3)(2) : Dy phosphors. The kinetics parameters of 234 degrees C TL peak of Sr2Mg(BO3)(2) Dy-0.04(3+), (Li-0.04(+)) phosphor with the values of trap depth E=1.1 eV, frequency factor s=6.3 x 10(9) s(-1) were estimated by a peak shape method, which obey the second order kinetics.

Tris(2,2 '-bipyridyl) ruthenium(II) doped silica film modified indium tin oxide electrode and its electrochemiluminescent properties

An approach was reported to synthesize silica hybridized ruthenium bipyridyl complex through amidation reaction by covalent attachment of bis(bipyridyl)-4,4'-dicarboxy-2,2'-bipyridyl-ruthenium to (3-aminopropyl)-triethoxysilane. The hybrid complex then was gelatinized through acid catalytic hydrolysis method and a sol-gel modified indium, tin oxide electrode was prepared via spin coating technique. As prepared indium tin oxide electrode possesses good stability therein with excellent electrochemiluminescence behavior.

铁系3,4-聚异戊二烯橡胶的性能

考察了以异辛酸铁、三异丁基铝和偶氮二异丁腈催化剂在己烷中50℃下制备的3,4-聚异戊二烯(3,4-IR)[3,4(+1,2)结构质量分数约为50%,ML110+04℃为52,玻璃化转变温度为-21.6℃]与SBR或NR质量比为20/80组成的共混胶的力学性能和粘弹性能。SBR/3,4-IR和NR/3,4-IR共混胶与SBR或NR相比,其拉伸强度和扯断伸长率有所下降,回弹性明显降低,但硬度基本不变。根据0℃和60℃下的损耗因子tanδ值可知,3,4-IR可明显提高SBR或NR硫化胶的抗湿滑性能,并使滚动阻力有所降低。

Water resistant sulfonated polyimides based on 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BNTDA) for proton exchange membranes

A series of sulfonated polyimides (SPIs) were synthesized in in-cresol from 4,4'-binaphthyl- 1,11,8,8'-tetracarboxylic dianhydride (BNTDA), 4.4'-diaminodiphenylether-2,2-disulfonicacid (ODADS), and 4.4'-diamino-diphenyl ether (ODA) in the presence of triethylamine and benzoic acid. The resulted polyimides showed much better water resistance than the corresponding sulfonated polyimides from 1,4,5,8-naphthatenetetracarboxylic dianhydride (NTDA) and ODADS, which is contributed to the higher electron density in the carbonyl carbon atoms of BNTDA. Copolyimides S-75 and S-50 maintained their mechanical properties and proton conductivities after aging in water at 100 degrees C for 800 h. The proton conductivity of these SPIs was 0.0250-0.3565 S/cm at 20 degrees C and 100% relative humidity (RH), and increased to 0.11490.9470 S/cm at 80 degrees C and 100% RH. The methanol permeability values of these SPIs were in the range of 0.99-2.36 x 10(-7) cm(2)/S, which are much lower than that of Nafion 117 (2 x 10(-6) cm(2)/s).

Tetraaqua(1,10-phenanthroline-kappa N-2,N ')cobalt(II) dinitrate: a hydrogen-bonded supramolecular network

The structure of the title compound, [Co(C12H8N2)(H2O)(4)]-(NO3)(2), consists of tetraaqua(1,10- phenanthroline)cobalt(II) cations and nitrate anions. The Co atom is located on a twofold rotation axis and is coordinated by the two N atoms of a 1,10-phenanthroline ligand and four O atoms of water molecules. The cations and anions are linked by hydrogen-bond interactions into a three-dimensional supramolecular network.

Electrosynthesis and characterization of 1,2-dibenzyl C-60: A revisit

A reinvestigation of the reaction between C-60(2-) and benzyl bromide in benzonitrile containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) has shown that there are more reaction products than previously reported. Use of a silica rather than a "Buckyclutcher I" column for HPLC purification led to isolation of two previously unattained products in the reaction mixture, one of which was identified as 1,2-(PhCH2)(2)C-60 by UV-vis and NMR. The earlier incorrectly assigned 1,2-(PhCH2)(2)C-60 was identified as the methanofullerene C61HPh by X-ray single-crystal diffraction. The electrochemistry of genuine 1,2-(PhCH2)(2)C-60 shows that its first reduction potential in PhCN containing 0.1 M TBAP is cathodically shifted by 100 mV with respect to E-1/2 for reduction of 1,4-(PhCH2)(2)C-60, indicating that the addition pattern significantly affects the electrochemistry of derivatized C-60. Visible and near-IR spectra of the monoanion and dianion of 1,2-(PhCH2)(2)C-60 are also reported.

Fabrication and luminescent properties of rare earths-doped Gd-2(WO4)(3) thin film phosphors by Pechini sol-gel process

Rare earth ions (Eu3+ and Dy3+)-doped Gd-2(WO4)(3) phosphor films were prepared by a Pechini sol-gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and photoluminescence (PL) spectra as well as lifetimes were used to characterize the resulting powders and films. The results of XRD indicate that the films begin to crystallize at 600degreesC and the crystallinity increases with the elevation of annealing temperatures. The film is uniform and crack-free, WO(4)(2-)mainly consists of closely packed fine particles with an average grain size of 80 nm. Owing to an energy transfer from 4 groups, the rare earth ions show their characteristic emissions in crystalline Gd-2(WO4)(3) phosphor films, i.e., D-5(J) -F-7(J), (J = 0, 1, 2, 3; J' = 0 1, 2, 3, 4, not in all cases) transitions for Eu3+ and F-4(9/2)-H-6(J) (J = 13/2, 15/2) transitions for D Y3+, with the hypersensitive transitions D-5(0)-F-7(2) (Eu3+) and F-4(9/2) - H-6(13/2) (Dy3+) being the most prominent groups, respectively.

Heptaaquatetra-mu(3)-hydroxy-hexa-mu(2)-L-leucine-(L-leucine)tetraytterbium(III) tetrachlorozinc(II) trichlorohydroxyzinc(II) tetrachloride octahydrate

The title bimetallic compound, [Yb-4(mu(3)-OH)(4)(C6H13NO2)(7)-(H2O)(7)][ZnCl4][ZnCl3(OH)]Cl-4.8H(2)O, was synthesized at near physiological pH (6.0). The compound exhibits some novel structural features, including an asymmetric [Yb-4(mu(3)-OH)(4)(L-leucine)(7)(H2O)(7)](8+) complex cation in which four OH groups act as bridging ligands, linking four Yb3+ cations into a Yb4O4 structural unit. Each pair of adjacent Yb3+ ions is further bridged by one carboxy group from a leucine ligand. Water molecules and a monodentate leucine ligand also coordinate to Yb3+ ions, completing their eight-coordinate square-antiprismatic coordination. The Yb-4(mu(3)-OH)(4)(L-leucine)(7)(H2O)(7)](8+) cation, the [ZnCl4](2-), [ZnCl3OH](2-) and Cl- anions, and the lattice water molecules are linked via hydrogen bonds.

Preparation and properties of microporous membrane from poly(vinylidene fluoride-co-tetrafluoroethylene) (F2.4) for membrane distillation

Flat-sheet microporous membranes from F2.4 for membrane distillation (MD) were prepared by phase inversion process. Dimethylacetamide (DMAC) and LiClO(4)(.)3H(2)O/trimethyl phosphate (TMP) were, respectively, used as solvent and pore-forming additives. The effects of casting solution composition, exposure time prior to coagulation and temperature of precipitation bath on F2.4 membrane structure were investigated. The morphology of resultant porous membrane was observed by scanning electron microcopy. Some natures of F2.4 porous membrane after drying in air, such as mechanical properties and hydrophobicity, were exhibited and compared with poly(vinylidene fluoride) (PVDF) membrane prepared by the same ways. Stress-at-break and strength stress of F2.4 microporous membrane are higher than that of PVDF membrane, and elongation percentage of F2.4 membrane at break is about eight-fold as great as that of PVDF membrane. Contact angle of F2.4 microporous membrane to water (86.6 +/- 0.51degrees) was also larger than that of PVDF mernbrane (80.0 +/- 0.78degrees). MD experiment was carried out using a direct contact membrane distillation (DCMD) configuration as final test to permeate performance of resultant microporous membrane.

Synthesis and properties of soluble polyimides based on isomeric ditrifluoromethyl substituted 1,4-bis(4-aminophenoxy)benzene

A new fluorinated diamine monomer, [1,4-bis(4-amino-3-trifluoromethylphenoxy)benzene (2)], and a known isomeric analog 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (3) were synthesized. A series of organosoluble polyimides Ia-d and IIa were prepared from the diamines (2, 3) and dianhydrides (a-d) by a high-temperature one-step method. The effects of the trifluoromethyl substituents on the properties of polyimides were evaluated through the study of their soluble, thermal, optical, and gas permeability properties. Polyimides (Ia-d) had glass transition temperatures between 229 and 279 degrees C, and the temperatures at 5% weight loss ranged from 510 to 533 degrees C under nitrogen. These polyimides could be cast into flexible and tough membranes from DMAc solutions. The membranes had tensile strengths in the range of 137-169 MPa, tensile modulus in the range of 1.6-2.2 GPa and elongations at break from 11% to 14%. The polyimide la with trifluoromethyl groups ortho to the imide nitrogen exhibited enhanced gas permeability, solubility, transparency, and thermal stability compared with the isomeric polyimide IIa with the CF3 group meta to the imide nitrogen.