理想与还原Fe2O3[001]表面上汞吸附协同催化CO分解作用

煤化学链燃烧必然释放汞,汞与载氧体表面相互作用,影响表界面的氧化还原反应。本文采用密度泛函理论计算,研究汞（Hg⁰）在理想表面（Fe₂O₃[001]）和一系列被还原表面（Fe₂O_2.75、Fe₂O_2.5、Fe₂O_2.25、Fe₂O_1.625、Fe₂O_0.875、Fe₂O_0.375和Fe）的吸附,以及Hg⁰对Fe₂O_1.625、Fe₂O_0.875、Fe₂O_0.375和Fe等表面催化CO分解反应的协同作用机理。Hg⁰物理吸附在理想Fe₂O₃[001]表面。随着Fe₂O₃[001]表面不断被还原,Hg⁰发生化学吸附。Hg⁰吸附降低了CO与Fe₂O₃、Fe₂O_2.75、Fe₂O_2.5和Fe₂O_2.25等表面之间的相互作用,抑制O传递氧化CO为CO₂的反应;载氧体进一步还原过程中,Hg⁰吸附促进了CO与Fe₂O_1.625、Fe₂O_0.875、Fe₂O_0.375及Fe等表面之间的相互作用,进而促进了表面对CO的催化分解反应,加速了载氧体表面的积碳,降低了化学链燃烧效率。因此,合理控制载氧体的还原程度既可以减弱Hg⁰的吸附,也可以抑制积碳的形成,这对化学链燃烧的操作优化至关重要。     

Au/Ag复合纳米笼在表面增强拉曼光谱中的应用

表面增强拉曼光谱（SERS）技术是一种基于贵金属纳米结构基底对被检测物进行高灵敏度检测的一种方法.具有特殊纳米结构的贵金属表面受到激光的照射时，金属表面的自由电子会受到极大的振荡，当入射光频率与振荡频率相近时，则会发生表面等离子体共振现象（SPR），使金属表面的局域电场强度极大增强，入射光强度和散射光强度都得到成倍的放大，从而使吸附在贵金属纳米结构表面的分子的拉曼散射信号得到有效的增强.使用NaBH₄还原-酸刻蚀模板法，制备了八面体Au/Ag复合纳米笼，其形貌规整，尺寸均匀约为600 nm，无Cu₂O模板的残留，Au元素均匀负载在Ag纳米笼上，质量分数约为16.8%；Au/Ag复合纳米笼的紫外可见吸收峰相对于Ag纳米笼发生了红移，更重要的是，Au和Ag元素协同赋予了复合纳米笼超高的SERS灵敏度和重复性，Au/Ag复合纳米笼实现了对罗丹明6G的痕量检测（5×10^-14 mol/L），通过时域有限差分法（FDTD）模拟证实：这主要归因于等离子共振作用产生的高电磁场强度；此外，Au元素的加入使Au/Ag复合纳米笼具有优异的抗氧化性和化学稳定性，即使在1%的H₂O₂溶液中浸泡3 h，仍然能够保持优异的SERS性能.八面体Au/Ag复合纳米笼有望成为一种具有应用前景的高灵敏度、高稳定性的SERS基底.     

基于荧光聚合物-氧化铁磁性纳米复合材料的汞离子探针

将端炔取代的共轭聚合物（P）与叠氮硅烷包覆的氧化铁磁性纳米微球（Fe₃O₄@Si-N₃）通过click反应共价连接，制备出了一种双功能的荧光-磁性纳米复合材料Fe₃O₄@Si@P。此纳米材料的荧光信号能够被I^-特异地淬灭。再利用Hg²⁺和I^-之间的强络合作用，可将I^-从Fe₃O₄@Si@P/I^-复配体系中脱离，从而使Fe₃O₄@Si@P的荧光信号恢复。Fe₃O₄@Si@P/I^-复配体系对Hg²⁺的检出限为0.19μmol/L。Fe₃O₄@Si@P可作为一种检测Hg²⁺的可逆型荧光-磁性纳米复合材料。     

超顺磁性Fe3O4/Au@Ag复合材料的合成及其SERS性能研究

利用溶剂热法和种子生长法分别合成Fe₃O₄磁性纳米粒子和Au@Ag核壳纳米粒子, 利用静电吸附方法成功将聚乙酰亚胺(PEI)修饰到Fe₃O₄表面并通过N-Ag共价键将Au@Ag核壳纳米粒子组装到Fe₃O₄表面, 制备Fe₃O₄/Au@Ag复合材料. 通过控制Au@Ag复合粒子的加入量, 来调节Fe₃O₄/Au@Ag复合材料的表面增强拉曼(SERS)活性. 以对巯基苯胺(p-ATP)为拉曼活性探针分子来考察该复合纳米材料的SERS性能, 检测限可以低至2×10^-9 mol/L. 同时, 将该复合材料应用于农药分子福美双的检测, 检测限可以低至10^-6 mol/L. 这种功能性复合材料既具有良好的SERS活性, 又具有Fe₃O₄磁性内核, 可以通过外加磁场实现对待测分子的分离、富集, 具有更广泛的应用前景.     

Fe3O4@Au核-壳纳米复合材料的制备及对农药福美双的SERS检测研究

首先采用热分解法制备了Fe₃O₄纳米材料, 再将其作为磁性核, 分别采用种子沉积法和种子介导生长法制备了Fe₃O₄-Au核-卫星纳米复合材料和Fe₃O₄@Au核-壳纳米复合材料, 并对其形貌和性能进行了表征分析. 结果表明, 所制备的Fe₃O₄-Au核-卫星和Fe₃O₄@Au核-壳纳米复合材料粒径均匀, Au纳米颗粒均匀沉积/包覆在Fe₃O₄纳米材料表面, 且样品均具有良好的磁响应性. 使用4-氨基苯硫酚(4-ATP)作为拉曼探针分子, 对比了这两种纳米复合材料作为SERS基底时的拉曼信号增强效果. 结果显示, Fe₃O₄@Au核-壳纳米复合材料是更优秀的SERS基底, 且该SERS基底具有良好的信号再现性. 最后, 使用Fe₃O₄@Au核-壳纳米复合材料作为SERS基底, 成功地在苹果皮上检测出残留福美双的SERS信号.     

微流控芯片结合表面增强拉曼光谱实时监测α-苯乙醇的微量合成反应

表面增强拉曼光谱（SERS）因极高的检测灵敏度且能够提供丰富的分子结构信息,可实现原位、实时监测等优点而成为广受关注的痕量分析工具.本文发展了基于微流控和SERS的联用技术,实现了微有机合成反应的现场监测.以磁性核壳纳米粒子Fe₃O₄@Ag为SERS基底,通过外加磁场调控富集实现连续的SERS检测;结合微流控反应器在有机合成中反应物用量少、效率高、易于实现在线检测和高通量筛选的优势,实现了α-苯乙醇的微量合成反应以及实时SERS监测.研究表明,Fe₃O₄@Ag核壳纳米粒子具备在微流控反应通道中的磁富集功能和SERS连续检测的性能.通过改变微流控通道中反应物的流速可调控反应速度,在固定时间内获得不同浓度的反应物,利用差谱技术消除反应物光谱的干扰,获得了产物α-苯乙醇的特征SERS光谱.结果表明微流控技术与SERS联用可发展成为微量有机反应的监测手段,在有机化学反应高通量筛选中具有潜在应用价值.     

基于Fe3O4@SiO2@Ag/GCE传感器检测土霉素

合成了具有核壳结构的Fe₃O₄@SiO₂纳米复合材料,在Fe₃O₄@SiO₂表面负载银纳米离子,制备了一种新型的Fe₃O₄@SiO₂@Ag复合材料,并采用玻碳电极(GCE)构建Fe₃O₄@SiO₂@Ag/GCE传感器,对土霉素(OTC)进行定量检测。优化了电解质溶液的种类和pH,Fe₃O₄@SiO₂@Ag用量以及富集时间和富集电位等实验条件。在最佳条件下,OTC浓度(c)与峰电流(I_p)在0.01～120μmol/L范围内呈线性关系,线性方程为I_p=0.9307c-0.0033,线性相关系数R²=0.9986,检出限为8.2 nmol/L。该传感器对牛奶中OTC的检测结果与国标法结果一致。     

基于等离子激元耦合效应的高灵敏汞离子传感器

提出了一种基于单颗粒光谱技术,能够高灵敏检测汞离子的新方法,原理是基于汞离子诱导的纳米金自组装过程.在两种不同大小的纳米金表面分别修饰两段富含T碱基的DNA序列,当Hg²⁺存在时,两段DNA序列自发形成双链结构,导致小金球能够在大金球表面自组装成核-卫星纳米金结构,这一过程伴随着纳米颗粒散射光颜色和散射峰位置的变化,变化的程度与Hg²⁺浓度具有相关性,依托单颗粒光谱技术极高的检测灵敏度,该方法可以实现pmol/L级的检测.     

多功能Fe3O4@SiO2 Janus颗粒

采用溶剂热法和溶胶-凝胶法制备了顺磁性Fe₃O₄@SiO₂颗粒,以Pickering乳液界面保护法实现颗粒表面分区获得Fe₃O₄@SiO₂ Janus颗粒,进一步选区复合生长Pt或Ag纳米颗粒制备Fe₃O₄@SiO₂-Pt和Fe₃O₄@SiO₂-Ag Janus颗粒.Fe₃O₄@SiO₂-Pt Janus颗粒的Pt一侧进行催化过氧化氢的反应,具有自驱动功能.因其顺磁性和两亲性,Fe₃O₄@SiO₂-Ag Janus颗粒能够作为磁响应颗粒乳化剂稳定油水乳液,并将Ag的催化功能引入界面.     

铬酸根离子的SERS检测及磁分离研究

介绍了一种基于表面增强拉曼光谱技术(SERS)的简单快速检测低浓度铬酸根离子的方法. 通过介质中水与铬酸根离子以及修饰在金基底和金纳米粒子表面的羧酸根形成氢键而构建“巯基苯甲酸-金基底/铬酸根-水/巯基苯甲酸-金纳米粒子”三明治结构. 通过检测标记分子的SERS信号判断溶液中是否存在铬酸根离子. 研究表明标记分子的SERS强度与铬酸根离子的浓度有关, 随浓度增加SERS强度呈非线性增强, 在10^－9 mol/L出现转折点. 利用以上三明治结构, 通过引入功能化的Fe₂O₃@Au核壳磁性纳米粒子, 利用外加磁场可富集分离溶液中的铬酸根离子, 经SERS 检测表明10^－5 mol/L的铬酸根离子磁分离后其浓度降低了约4～6个数量级.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Trichlorotrirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of four Linkage Isomeric Trichlorotrirhodanoosmates(IV) By treatment of fac-[OsCl₃I₃]^2? with (SCN)₂ in dichloromethane the linkage isomers fac-[OsCl₃(NCS)₃]^2? ( 1 ), mer-[OsCl₃(NCS)₂^c(SCN)]^2? ( 2 ), mer-[OsCl₃(NCS)(SCN)₂^t]^2? ( 3 ), and mer-[OsCl₃(NCS)(SCN)₂^c]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X-Ray structure determinations have been performed on single crystals of fac-(Ph₄As)₂[OsCl₃(NCS)₃] (triclinic, space group P1 , a = 12.142(5), b = 13.233(5), c = 19.300(5) Å, α = 98.642(5)º, β = 100.509(5)º, γ = 112.514(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)₂^c (SCN)] · acetone (triclinic, space group P1 , a = 11.707(5), b = 13.238(5), c = 19.048(5) Å, α = 75.960(5)º, β = 88.981(5)º, γ = 69.999(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^t] (triclinic, space group P1, a = 10.6861(12), b = 11.6587(5), c = 12.5232(5) Å, α = 112.069(8)º, β = 95.052(8)º, γ = 92.559(7)º, Z = 1) and mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^c] · 2acetone (triclinic, space group P1 , a = 11.444(5), b = 14.661(5), c = 15.830(5) Å, α = 75.790(5)º, β = 80.273(5)º, γ = 75.205(5)º, Z = 2). The complex anions are completely ordered. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 169.1º, 171.5º, 175.7º ( 1 ), 175.6º, 178.6º ( 2 ), 172º ( 3 ), and 173.1º ( 4 ) and Os? S? C angles of 106.2º ( 2 ), 106.1º, 106.6º ( 3 ), 105.1º, and 108.2º ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers have been assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.71 ( 1 ), 1.46 and 1.62 ( 2 ), 1.69 ( 3 ), and 1.61 ( 4 ), f_d(OsS) = 1.27 ( 2 ), 1.36 ( 3 ), 1.32, and 1.49 mdyn/Å ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Tetrachlorodirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl₄I₂]^2? with (SCN)₂ in dichloromethane the linkage isomers cis-[OsCl₄(NCS)₂]^2? ( 1 ), trans-[OsCl₄(NCS)(SCN)]^2? ( 2 ), cis-[OsCl₄(NCS)(SCN)]^2? ( 3 ) and trans-[OsCl₄(SCN)₂]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph₄As)₂[OsCl₄(NCS)₂] (triclinic, space group P1 , a = 10.019(5), b = 11.702(5), c = 21.922(5) Å, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph₄As)₂[OsCl₄ · (NCS)(SCN)] (monoclinic, space group P2₁/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) Å, β = 94.208(5)°, Z = 4), cis-(Ph₄As)₂[OsCl₄(NCS)(SCN)] (triclinic, space group P1 , a = 10.579(5), b = 11.682(5), c = 22.557(5) Å, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph₄As)₂ · [OsCl₄(SCN)₂] (triclinic, space group P1 , a = 10.615(5), b = 11.691(5), c = 11.907(5) Å, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 171.2° and 174.3° ( 1 ), 162.3° ( 2 ), 172° ( 3 ) and Os? S? C angles of 108.3° ( 2 ), 105.7° ( 3 ) and 105.5° ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.59 ( 1 ), 1.67 ( 2 ), 1.60 ( 3 ) and f_d(OsS) = 1.27 ( 2 ), 1.31 ( 3 ) and 1.32 mdyn Å^?1 ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Darstellung und Kristallstruktur von (n-Bu4N)3[Ir(NCS)(SCN)5]

Preparation and Crystal Structure of (n-Bu₄N)₃[Ir(NCS)(SCN)₅] The evaporated ethanolic extrakt of the reaction product of K₃[IrCl₆] and HNO₃, refluxed with an aqueous KSCN solution yields a mixture of the linkage isomers [Ir(NCS)_n(SCN)_6?-n]^3?, n = 0? 2, and small amounts of linkage isomeric chloropentarhodanoiridates(III), from which [Ir(NCS)(SCN)₅]^3? has been isolated by ion exchange chromatography on DEAE-cellulose. The X-Ray structure determination on a single crystal of (n-Bu₄N)₃[Ir(NCS)(SCN)₅] (monoclinic, space group P 2₁/a, a = 17.513(5), b = 32.607(5), c = 23.661(5) Å, β = 94.757(5)°, Z = 8) confirms the existance of a heteroleptic hexakis(thiocyanato(N)-thiocyanato(S))iridate(III) with an Ir? N distance of 2.03 Å and Ir? S bond lengths between 2.29 and 2.38 Å. The SCN groups with angles between 166 and 175° are nearly linear with Ir? S? C angles from 99.9 to 109.4°. The Ir? N? C angles of the two crystallographic independent anions are 166 and 174°.     

Comparative Thermogravimetric Studies of Poly(ether-ketone/sulfone) Imides and Their Parent Polymers: I. Poly(ether-ketone/sulfone) ethylimide

Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.This revised version was published online in November 2005 with corrections to the Cover Date.     

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES WITH AMPICILLIN

Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]₂ × nH₂O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

Thermal Degradation of Poly(ε-caprolactone), Poly(L-lactic acid) and their Blends with Poly(3-hydroxy-butyrate) Studied by TGA/FT-IR Spectroscopy

Summary: The thermal degradation behavior of poly(ε-caprolactone) (PCL) and poly(L-lactic acid) (PLA) have been studied in different environment. It was found that these polymers undergo completely different degradation processes in nitrogen and oxygen atmosphere. In oxygen environment PCL and PLA mainly decompose to CO₂, CO, water and short-chain acids. In nitrogen atmosphere PCL releases 5-hexenioc acid, CO₂, CO and ε-caprolactone, whereas PLA decomposes to acetaldehyde, CO₂, CO and lactide. The polymer blends of poly(3-hydroxybutyrate) (PHB) with PCL and PLA decompose similar to the individual homopolymers with crotonic acid as the initial decomposition product of PHB.     

Energy relationship and the polarization of C_(60) cage in the endohedral complexes (X@C_(60))

In this paper, we carry out the calculation on the system (X@C60)(X=Li, Na, K, Kb, Cs; F, Cl, Br, I), where the position of X changes along 5 typical symmetry directions. For the calculation of quantum chemistry we use EHMO/ASED method, for the calculation of molecular mechanics we use Buckingham potential (exp-6-1) function, and for the calculation of thermo-chemical cycle we use individually isolating the processes such as the structure variation, charge transfer and charge distribution, and their interactions etc. The calculation results show that (1) In the region of radius r≈0.2 nm of the Ceo cage, the potential field is nearly spherical; (2) Except for Li and Na, the systems are the most stable with minimum energies at the center of C60 cage. For Li and Na, the systems are the most stable with minimum energies at r≈0.16 nm and r≈0.13 nm, respectively. In view of the interactive region of chemical bonds, the interactions between X and the C60 cage do not belong to the classical chemical bonds; (     

铜在3%NaCl溶液中腐蚀行为的光电化学研究

Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中．自然Cu的腐蚀和防腐成为人们很关注的问题．人们已经注意到，Cl-对Cu的腐蚀有影响，并进行过一些研究．但目前使用光电化学方法研究这一问题的文章尚不多见，特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到．本文正是利用如上方法及XPS，AES方法，研究了Cl-对Cu电极腐蚀的全过程，取得了一些有意义的结果．1实验方法Cu电极用99．99％（质量分数）的Cu制成，面积约为39mm2；电极底部由Cu导线焊接引出，…     

On the morphological behavior of ABC miktoarm stars containing poly(cis 1,4-isoprene), poly(styrene), and poly(2-vinylpyridine)

Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by small-angle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders in undulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1491–1504