FRS-XRSA与SAXS研究硬弹性聚丙烯的结晶度、取向与超结构Ⅲ应变与回复

应用全倒易空间Ｘ 射线散射理论分析（ＦＲＳ ＸＲＳＡ）与ＳＡＸＳ研究了ＨＥＰＰ在应变（ε）与回复（Ｒ）过程中结晶、取向与超结构的变化．结果指出，ε可以诱发结晶，但当ε≥３０％后，结晶度（ＸＷＣ）趋于不变：ε可以导致晶粒破碎；ε与Ｒ对取向分布与平均取向基本上无影响，这符合片晶平行分离模型，而非叶簧弯曲模型；发现，在ε≤３０％时，层状片晶的分离为主要过程，而当ε＞３０％后，则分离的片晶会发生断层滑移；ε可以诱发微孔，类似地当ε＞２０％，微孔尺寸亦趋不变．从凝聚态结构阐明了ＨＥＰＰ在ε Ｒ过程中不同阶段的结构变化     

REPS4(RE=Y, La～Lu)系列化合物的合成和结构化学研究

采用高温固相反应合成了稀土硫代磷酸盐ＲＥＰＳ４（ＲＥ＝Ｙ，Ｌａ～Ｌｕ），并通过Ｘ射线粉末衍射测定了晶胞参数以及ＨｏＰＳ４，ＥｒＰＳ４和ＴｍＰＳ４的晶体结构。其中ＲＥＰＳ４（ＲＥ＝Ｙ，Ｌａ～Ｙｂ）系列化合物的结构均属四方晶系，其空间群为Ｉ４１／ａｃｄ，ａ≈１１ｎｍ，ｃ≈１９ｎｍ，Ｚ＝１６。四方结构中的三价稀土离子为反四方棱柱八配位。该结构具有较大的孔洞空间，孔洞直径分别为０６２５ｎｍ（沿ｃ轴方向）和０３５ｎｍ（沿ａ、ｂ轴方向）。ＬｕＰＳ４晶体为单斜晶系，很可能是层状（２Ｄ）结构。研究了镧系收缩效应对四方结构稳定性的影响，发现对ＲＥＡＸ４系列化合物来说，四方结构能稳定存在的前提是２４ｄＡＸ／ｒ１９。     

SYNTHESIS, CHARACTERIZATION OF 2-[2-(3-NITRO-4-METHOXYLPHENYL) VINYLI-1-ME

ＳＹＮＴＨＥＳＩＳ，ＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦ２－［２－（３－ＮＩＴＲＯ－４－ＭＥＴＨＯＸＹＬＰＨＥＮＹＬ）ＶＩＮＹＬＩ－１－ＭＥＴＨＹＬＰＹＲＩＤＩＮＩＵＭＰＥＮＴＡＡＮＤＨＥＸＡＮＩＴＲＡＴＯＲＡＲＥＥＡＲＴＨ（Ⅲ）ＣＯＭＰＬＥＸＥＳＨ...     

NONTEMPLATE SYNTHESIS OF TWO N_2O_2S MACROCYCLES DERIVED FROM THIOPHENE，AND Hg（Ⅱ）， Pb（Ⅱ）， Cd（Ⅱ） COMPLEXES

ＮＯＮＴＥＭＰＬＡＴＥＳＹＮＴＨＥＳＩＳＯＦＴＷＯＮ_２Ｏ_２ＳＭＡＣＲＯＣＹＣＬＥＳＤＥＲＩＶＥＤＦＲＯＭＴＨＩＯＰＨＥＮＥ，ＡＮＤＨｇ（Ⅱ），Ｐｂ（Ⅱ），Ｃｄ（Ⅱ）ＣＯＭＰＬＥＸＥＳ￥ＬｉｎｇＺＨＡＯ；ＦｕＸｉｎＸＩＥ；ＺｈｉＱｉａｎｇＸＵ；Ｇｕａ...     

铁催化剂对煤热解过程中氮元素迁移的影响

应用ＸＲＤ和ＥＸＡＦＳ技术表征了热解温度对煤中铁催化剂形态的影响，用ＸＰＳ表面分析方法研究了铁催化剂对煤热解过程中氮元素迁移的影响。结果表明：铁元素在低温制备煤焦中的主要物相是Ｆｅ２Ｏ３和Ｆｅ３Ｏ４，而在高温制备的煤焦中，还原态α－Ｆｅ和铁碳物种（Ｆｅ，Ｃ）是铁元素的主要存在形态。煤或焦中的氮元素以季胺盐、吡啶和吡咯等三种形态存在。铁能催化季胺盐在较低温度下分解。与吡咯类氮相比较而言，铁能优先催化     

SYNTHESIS AND MAGNETISM OF μ－OXAMIDO COPPER（Ⅱ）－LANTHANIDE（Ⅲ）HETEROBINUCLEAR COMPLEXES

ＳＹＮＴＨＥＳＩＳＡＮＤＭＡＧＮＥＴＩＳＭＯＦμ－ＯＸＡＭＩＤＯＣＯＰＰＥＲ（Ⅱ）－ＬＡＮＴＨＡＮＩＤＥ（Ⅲ）ＨＥＴＥＲＯＢＩＮＵＣＬＥＡＲＣＯＭＰＬＥＸＥＳ￥ＣｕｉＷｅｉＹＡＮ（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｌｏｇｙ，ＱｕｆｕＮｏｒｍａｌＵｎｉｖｅ...     

THE EXCITED STATES AND VIBRATIONAL FREQUENCIES OF Bli_2~e（e＝0，＋1，－1）CLUSTERS

ＴＨＥＥＸＣＩＴＥＤＳＴＡＴＥＳＡＮＤＶＩＢＲＡＴＩＯＮＡＬＦＲＥＱＵＥＮＣＩＥＳＯＦＢｌｉ：（ｅ＝０，＋１，－１）ＣＬＵＳＴＥＲＳＴＨＥＥＸＣＩＴＥＤＳＴＡＴＥＳＡＮＤＶＩＢＲＡＴＩＯＮＡＬＦＲＥＱＵＥＮＣＩＥＳＯＦＢｌｉ：（ｅ＝０，＋１，－１）Ｃ...     

STUDY ON CONTINUOUS ELECTROREGENERATION OF ION EXCHANGE RESIN

ＳＴＵＤＹＯＮＣＯＮＴＩＮＵＯＵＳＥＬＥＣＴＲＯＲＥＧＥＮＥＲＡＴＩＯＮＯＦＩＯＮＥＸＣＨＡＮＧＥＲＥＳＩＮＸｕＴａｉｓｈｕｎ（ＳｈａｎｇｈａｉｉｎｓｔｉｔｕｔｅｏｆＥｌｅｃｔｒｉｃＰｏｗｅｒ，Ｓｈａｎｇｈａｉ２０００９０，Ｃｈｉｎａ）Ａｂｓｔｒａｃ...     

稀土取代的复合氧化物Eu_（0．5）RE_（0．5）Fe_（0．5）Mn_（0．

利用固相反应合成了稀土取代的复合氧化物Ｅｕ_（０．５）ＲＥ_（０．５）Ｆｅ_（０．５）Ｍｎ_（０．５）Ｏ_３（ＲＥ＝Ｌａ，Ｐｒ，Ｎｄ，Ｓｍ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ）．测量了这些化合物的ＸＲＤ和ＸＰＳ谱。在ＸＰＳ研究中发现，稀土取代而使稀土元素本身的结合能相对于其倍半氧化物中的有所降低；在取代的复合氧化物中，随着ＲＥ离子半径的减小，Ｆｅ、Ｍｎ的结合能随之增加。     

A NEW PEROXYNIOBIUM－CONTAINING POLYOXOANION， P_2W_17（NbO_2）O_（61）~（7－） SYNTHESIS AND CHARACTERIZATION

ＡＮＥＷＰＥＲＯＸＹＮＩＯＢＩＵＭ－ＣＯＮＴＡＩＮＩＮＧＰＯＬＹＯＸＯＡＮＩＯＮ，Ｐ_２Ｗ_１７（ＮｂＯ_２）Ｏ_（６１）~（７－）ＳＹＮＴＨＥＳＩＳＡＮＤＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦＳＴＵＲＣＴＵＲＥ￥ＬｕｎＹｕＱＵ（ＤｅｐａｒｔｍｅｎｔｏｆＣ?..     

Theoretical study of the surface energy and electronic structure of pyrite FeS2 (100) using a total-energy pseudopotential method, CASTEP

The geometric and electronic structures of FeS(2) (100) surface have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code, CASTEP. The (100) surface is very stable and does not give any significant geometric relaxation. The electronic structure of FeS(2) (100) surface is characterized by the appearance of new native surface states in the bulk band gap, which correspond to antibonding mixed Fea-Ssp(3) states. These surface states play an important role as mediators of electron transfer on both anodic and cathodic sites in the incipient oxidation of pyrite. Moreover, the (100) surface has small band gaps and shows some metallic character. It is predicted that the rate of cathodic reductive reaction of O(2) in the incipient oxidation of pyrite is much faster than previously considered. The transport of electrons from the anodic sites to the cathodic sites on the (100) surface is faster and hole injection of anodic sites is not the rate-determining step. So we can deduce that the rate-determining step of incipient oxidation for pyrite consists of both electron transfer of pyrite/aqueous O(2) interface and the splitting of H(2)O.     

矿物中药自然铜的组成与热稳定性研究

采用X射线粉末衍射、热重-差热分析、等离子体发射光谱等分析手段, 对不同产地自然铜和煅自然铜的结构组成、热稳定性和微量元素进行测定和分析. 结果表明: 自然铜的主要物相为FeS2, 煅自然铜则因产地而异, 出现了FeS2(南京中医药大学样品中约86%, 湖南89%, 四川32%, 山西19%), FeS(湖南11%, 安徽24%, 四川24%), Fe3O4(安徽29%), Fe2O3(安徽14%)和FeO(OH) (南京中医药大学14%, 山西74%)等复杂物相. 自然铜在加热到450～800 ℃时, 逐渐发生了由FeS2转变为FeS的相变. 在这些药材中含有丰富的与人体健康密切相关的微量元素, 既含有对人体有益的Ca, Fe, Zn等微量元素, 也含有As, Cd, Pb等有害微量元素. 实验结果为该矿物药的鉴定和评价提供了科学数据.     

High-temperature FeS-FeS2 solid-state transitions: Reactions of solid mackinawite with gaseous H2S

Phase transitions and reactions of non-oxidized and surface-oxidized mackinawite (FeS) in helium and H₂S gas were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT). DFT was used to obtain optimized structures of the iron-sulfur phases mackinawite, hexagonal pyrrhotite, greigite, marcasite and pyrite and to determine the thermochemical properties of reactions of mackinawite with H₂S to these phases. The phase transitions of mackinawite to hexagonal pyrrhotite are endothermic, while reactions to greigite, marcasite and pyrite are exothermic. The experiments show that non-oxidized mackinawite converts into hexagonal pyrrhotite (Fe₉S₁₀ first and then Fe₇S₈) in He and also in H₂S but at a lower temperature. No further reactions can be observed under these conditions. In the case of surface-oxidized mackinawite, the extent of surface oxidation determines the course and the final product of the reaction with H₂S. If the extent of surface oxidation is low, only Fe²⁺ is oxidized to Fe³⁺. Under these conditions mackinawite converts into the mixed-valence thiospinel compound greigite. In case of pronounced surface oxidation all surface Fe centers are oxidized to the Fe³⁺ state and S²⁻ is oxidized to SO₄²⁻. Oxidation of sulfur is a prerequisite for the formation of pyrite.     

Production of a biomimetic Fe(I)-S phase on pyrite by atomic hydrogen beam surface reactive scattering

Molecular beam surface scattering and X-ray absorption spectroscopic experiments were employed to study the reaction of deuterium atoms with a pyrite, FeS(2) (100), surface and to investigate the electronic and geometric structures of the resulting Fe-S phases. Incident D atoms, produced by a radiofrequency plasma and expanded in an effusive beam, were directed at a pyrite surface held at various temperatures from ambient up to 200 °C. During exposure to the D-atom beam, D(2)S products were released with a thermal distribution of molecular speeds, indicating that the D atoms likely reacted in thermal equilibrium with the surface. The yield of D(2)S from the surface decreased approximately exponentially with exposure duration, suggesting that the surface accessible sulfur atoms were depleted, thus leaving an iron-rich surface. This conclusion is consistent with X-ray absorption measurements of the exposed surfaces, which indicated the formation of a layered structure, with elemental iron as the outermost layer on top of a formally Fe((I))-S phase as an intermediate layer and a formally Fe((II))-S(2) bulk pyrite layer at lower depths. The reduced Fe((I))-S phase is particularly remarkable because of its similarity to the catalytically active sites of small molecule metalloenzymes, such as FeFe-hydrogenases and MoFe-nitrogenases.     

A review of the fundamental studies of the copper activation mechanisms for selective flotation of the sulfide minerals, sphalerite and pyrite

A review of the considerable, but often contradictory, literature examining the specific surface reactions associated with copper adsorption onto the common metal sulfide minerals sphalerite, (Zn,Fe)S, and pyrite (FeS(2)), and the effect of the co-location of the two minerals is presented. Copper "activation", involving the surface adsorption of copper species from solution onto mineral surfaces to activate the surface for hydrophobic collector attachment, is an important step in the flotation and separation of minerals in an ore. Due to the complexity of metal sulfide mineral containing systems this activation process and the emergence of activation products on the mineral surfaces are not fully understood for most sulfide minerals even after decades of research. Factors such as copper concentration, activation time, pH, surface charge, extent of pre-oxidation, water and surface contaminants, pulp potential and galvanic interactions are important factors affecting copper activation of sphalerite and pyrite. A high pH, the correct reagent concentration and activation time and a short time delay between reagent additions is favourable for separation of sphalerite from pyrite. Sufficient oxidation potential is also needed (through O(2) conditioning) to maintain effective galvanic interactions between sphalerite and pyrite. This ensures pyrite is sufficiently depressed while sphalerite floats. Good water quality with low concentrations of contaminant ions, such as Pb(2+)and Fe(2+), is also needed to limit inadvertent activation and flotation of pyrite into zinc concentrates. Selectivity can further be increased and reagent use minimised by opting for inert grinding and by carefully choosing selective pyrite depressants such as sulfoxy or cyanide reagents. Studies that approximate plant conditions are essential for the development of better separation techniques and methodologies. Improved experimental approaches and surface sensitive techniques with high spatial resolution are needed to precisely verify surface structures formed after copper activation. Sphalerite and pyrite surfaces are characterised by varying amounts of steps and defects, and this heterogeneity suggests co-existence of more than one copper-sulfide structure after activation.     

Nitrogen adsorption and desorption at iron pyrite FeS2{100} surfaces

We have investigated the interaction of nitrogen with single-crystal iron pyrite FeS(2){100} surfaces in ultra-high vacuum. N(2) adsorbs molecularly at low temperatures, desorbing at 130 K, but does not adsorb dissociatively even at pressures up to 1 bar. Atomic surface N can, however, be obtained with nitrogen ions and/or excited neutral species, generated by passing N(2) through an ion gun. Substantial nitrogen-induced disorder is seen with both ions and neutrals, and no ordered N overlayers form; a decrease in the S/Fe ratio is seen when exposing to nitrogen ions. Recombinative desorption leads to temperature-programmed desorption peaks at 410 and 520-560 K which we associate with interstitial atomic N and substitutional ionic N, respectively, in the surface regions. Thermal repair of sputter damage necessitates segregation of bulk S to the surface, which, over repeated experiments, leads to gross cumulative damage to the bulk crystal. The desorption temperatures associated with recombinative desorption of atomic N from FeS(2){100} are significantly lower than those measured for Fe surfaces. This is linked to the inability of FeS(2){100} to dissociate N(2), but suggests that N(ads) will be significantly more able to react with other species than it is on Fe surfaces.     

Theoretical Study on the Reaction of FeS+(6∑+,4Ф)with COS in the Gas Phase

The possible reaction mechanisms of FeST(6∑+and 4Ф states)with COS in the gas phase have been studied by using density functional theory at the B3LYP/TZVP and B3LYP/6-311+G*levels:the O/S exchange reaction(FeS++COS=FeO++CS2),O-transfer reaction(FeS++COS=FeSO++CS)and S-transfer reaction(FeS++COS=FeS2++CO).The calculation results show that the large barriers(205.7 and 310.1 kJ/mol)and the small probability of forming the preceding intermediate indicate a much lower efficiency of the O/S exchange and the O-transfer reactions and their corresponding products may not be observed experimentally.FeS2+,the product of S-transfer reaction,is predicted to be the main product.But the reactivity of the 6∑+ground state of FeS+toward COS is lower than the earlier transition metal sulfide cations MS+(M=Sc,Ti and V),although it has more reaction channels and different mechanisms.     

X-ray absorption spectroscopy study of H2S sorption on iron-rich soil: characterization of iron-sulfur species

Iron-rich soil after sorption of H(2)S was characterized using X-ray absorption near-edge structural (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) for determination the possible products in the present work. EXAFS revealed that the main Fe-S species in the sulfided sample were FeS (troilite) and Fe(1-x)S (pyrrohotite). Iron in the sulfided sample was found to possess a Fe-S bond distance of 2.36 A and a Fe-O bond distance of 1.72 A in the Fe-K-edge spectra whereas the Fe-S bond distance of 2.25 A was determined in the sulfur K-edge spectra. In the second shells, the bond distance of Fe-O-Si or Fe-O-Al with 3.28 A was also observed. No FeS2 (pyrite) was included in the sulfided sample. The formation of Fe(1-x)S was probably attributed to the presence of Fe(3)O(4), a type of spinel structure with a lattice deficiency.     

Theoretical electron density distributions for Fe- and Cu-sulfide earth materials: a connection between bond length, bond critical point properties, local energy densities, and bonded interactions

Bond critical point and local energy density properties together with net atomic charges were calculated for theoretical electron density distributions, rho(r), generated for a variety of Fe and Cu metal-sulfide materials with high- and low-spin Fe atoms in octahedral coordination and high-spin Fe atoms in tetrahedral coordination. The electron density, rho(rc), the Laplacian, triangle down2rho(rc), the local kinetic energy, G(rc), and the oxidation state of Fe increase as the local potential energy density, V(rc), the Fe-S bond lengths, and the coordination numbers of the Fe atoms decrease. The properties of the bonded interactions for the octahedrally coordinated low-spin Fe atoms for pyrite and marcasite are distinct from those for high-spin Fe atoms for troilite, smythite, and greigite. The Fe-S bond lengths are shorter and the values of rho(rc) and triangle down2rho(rc) are larger for pyrite and marcasite, indicating that the accumulation and local concentration of rho(r) in the internuclear region are greater than those involving the longer, high-spin Fe-S bonded interactions. The net atomic charges and the bonded radii calculated for the Fe and S atoms in pyrite and marcasite are also smaller than those for sulfides with high-spin octahedrally coordinated Fe atoms. Collectively, the Fe-S interactions are indicated to be intermediate in character with the low-spin Fe-S interactions having greater shared character than the high-spin interactions. The bond lengths observed for chalcopyrite together with the calculated bond critical point properties are consistent with the formula Cu+Fe3+S2. The bond length is shorter and the rho(rc) value is larger for the FeS4 tetrahedron displayed by metastable greigite than those displayed by chalcopyrite and cubanite, consistent with a proposal that the Fe atom in greigite is tetravalent. S-S bond paths exist between each of the surface S atoms of adjacent slabs of FeS6 octahedra comprising the layer sulfide smythite, suggesting that the neutral Fe3S4 slabs are linked together and stabilized by the pathways of electron density comprising S-S bonded interactions. Such interactions not only exist between the S atoms for adjacent S8 rings in native sulfur, but their bond critical point properties are similar to those displayed by the metal sulfides.     

The interaction of iron pyrite with oxygen, nitrogen and nitrogen oxides: a first-principles study

Sulphide materials, in particular MoS(2), have recently received great attention from the surface science community due to their extraordinary catalytic properties. Interestingly, the chemical activity of iron pyrite (FeS(2)) (the most common sulphide mineral on Earth), and in particular its potential for catalytic applications, has not been investigated so thoroughly. In this study, we use density functional theory (DFT) to investigate the surface interactions of fundamental atmospheric components such as oxygen and nitrogen, and we have explored the adsorption and dissociation of nitrogen monoxide (NO) and nitrogen dioxide (NO(2)) on the FeS(2)(100) surface. Our results show that both those environmentally important NO(x) species chemisorb on the surface Fe sites, while the S sites are basically unreactive for all the molecular species considered in this study and even prevent NO(2) adsorption onto one of the non-equivalent Fe-Fe bridge sites of the (1 × 1)-FeS(2)(100) surface. From the calculated high barrier for NO and NO(2) direct dissociation on this surface, we can deduce that both nitrogen oxides species are adsorbed molecularly on pyrite surfaces.