IN SITU OBSERVATION OF MELTING AND CRYSTALLIZATION BEHAVIORS OF POLY(ε-CAPROLACTONE) ULTRA-THIN FILMS BY AFM TECHNIQUE

The melting and crystallization behaviors of poly(ε-caprolactone) (PCL) ultra-thin films with thickness from 15 nm to 8 nm were studied by AFM technique equipped with a hot-stage in real-time. It was found that melting can erase the spherulitic structure for polymer film with high thickness. However, annealing above the melting point can not completely erase the tree-like structure for the thinner polymer film. Generally, the structure formation of thin polymer films of PCL is controlled not only by melting and crystallization but also by dewetting during thermal annealing procedures, and dewetting predominates in the structure formation of ultra-thin films. However, the presence of tree-like morphology at 75 °C may be due to the strong interaction between PCL and mica surface, which may stick the PCL chains onto the mica surface during thermal annealing process. Moreover, the growth of the dendrites was investigated and it was found that crystallization is followed from a dewetted sample, and the branches did not grow with the stems. The crystallization of polymer in the ultra-thin films is a diffusion-controlled process. Both melting and crystallization behaviors of PCL in thin films are influenced by film thickness.     

Synthesis, Structure and Properties of (n-Bu_4N)_3[Mo_6O_18NNAr(NO_2)_2]

The title compound was synthesized and characterized by means of elemental analysis, IR, DTA-TG and UV. Its single crystal structure was solved by using direct methods. The compound crystallizes in the orthorhombic space group Pmc(?) with lattice parameters: a = 1. 7261(2), b=l. 7537(3), c=2. 4258(3) nm. V=7. 34220 nm3, F(000) = 3648, Z = 4. The structure was refined to conventional discrepancy factors of R=0. 060 for 3176 observed reflections [Ⅰ>3σ/(Ⅰ)]. The anion represents a modification of the well-known [Mo6O19]2- anion, in which a single terminal oxo group is replaced by a 2,4-dinitrophenyl hydrazine ligand while the structure integrity of the hexanuclear framework is maintained.     

[（n-C4H9）3SnO2C（CH2）2CO2Sn（C4H9-n）3]：A Novel Three-dimensional Framework Structure of Organotin Complex

The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3)A, V= 7446(2)A^3, Z= 8, Dc = 1.242 g/cm^3, μ=1.365 mm^-1, F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.     

多面体倍半硅氧烷制备有序介孔氧化硅材料

Octa(tetramethylammonium)-polyhedral oligomeric silsesquioxane(TMA-POSS) with cage-like structure was synthesized, the structure was characterized by NMR, FTIR and Elemental analyses. The mesoporous silica was prepared under alkaline condition using TMA-POSS as the silicon source and hexadecyltrimethylammonium bromide (CTAB) as the template, the structures of these products were characterized by XRD, TEM and nitrogen adsorption and desorption methods. The results indicate that the synthesized silica exhibites a well-ordered hexagonal pore structure with larger specific surface area. With increasing of CTAB molar ratio, the spacing of the crystal plane d100 is increased. The effects of the pH values on the mesoporous structure in the reaction system with different molar ratio of nPOSS / nCTAB were investigated. The synthesis mechanism of mesoporous silica was also discussed.     

Reaction-induced phase separation in rubber-modified epoxy resin

The phase separation mechanism,and structure development during curing of epoxy with a novel liquid rubber-ZR were investigated by time-resolved light scattering,optical microscope and differential scanning calonmetry (DSC) The mixture loaded with curing agent was a single-phase system in the early stage of curing.When the cure reaction proceeded,phase separation took place via the spinodal decomposition induced by polymerization of epoxy resin.This was supported by the characteristic change of light scattering profile with curing time.Cure reaction plays an important role in the progress of phase separation.The bigger the cure reaction rate is,the longer periodic distance will be.The overall two-phase structure was basically locked in when the conversion approached 80% estimated by DSC,and finally the co-continuous two-phase structure was successfully obtained.     

Electrochemical Metalloimmunoassay Based on Enlargement of Gold Nanoparticle Label Treated with Ag Enhancement System

A novel sensitive electrochemical immunoassay with colloidal gold as the antibody labeling tag and subse-quent signal amplification by silver enhancement is described. Colloidal gold was treated by a light-sensitive silver enhancement system which made silver deposit on the surface of colloidal gold(form Au/Ag core-shell structure), followed by the release of the metallic silver atoms anchored on the antibody by oxidative dissolu-tion of them in an acidic solution and the indirect determination of the dissolved Ag ions by anodic stripping voltamrnetry(ASV) at a carbon fiber microelectrode. The electrochemical signal is directly proportional to the amount of analyte(goat IgG) in the standard or a sample, The method was evaluated by means of a non-competitive heterogeneous immunoassay of immunoglobulin G(IgG) with a concentration as low as 0. 2 ng/mL. The high performance of the method is related to the sensitive ASV determination of silver( I ) at a car-bon fiber microelectrode and to the release of a large number of Ag^ ions from each silver shell anchored on the analyte (goat IgG).     

SYNTHESIS AND NMR CHARACTERIZATION OF PRECURSORS OF EPOXY NETWORK AS POLYMER HOST FOR SOLID ELECTROLYTE

To raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a noncrystalline two-component epoxy electrolyte system has been prepared. The diglycidyl ether of polyethylene glycols as precursors of the system were synthesized by a two-step process. The presumed structure of the product was characterized, by ~(13)C, ~1H NMR and IR spectroscopy. It was found that a side-reaction occurred between the secondary hydroxyl group of PEG-chlorohydrin and epichlorohydrin in some degree, resulting in a by- product containing—CH_2Cl side group. By selecting a characteristic signal, which is undistorted by the increase in the length of CH_2 CH_2—O segment, a ~1H NMR approach of determining the equivalent epoxy weight (EEW) was proposed. The method is valid to specimens even though the EEW is as high as 2,000. The examination of the specimens by DSC showed that epoxidation greatly depressed the crystallinity of the PEG's, whereas the T_g was raised.     

Study on Stability of Nateglinide Polymorphism

The stability of three forms of nateglinide, especially S-form and H-form, was determined. S-form was a new crystal structure of nateglinide. Three forms of nateglinide were treated in different conditions, such as in various temperatures, humidity, light and so on.Analysis of their crystal structures was performed by X-ray powder diffraction ( XRD ) and their particle shapes were observed with scanning electron microscope ( SEM ). The results indicated that the stability of S-form of nateglinide is the best among the three forms and their particle shapes are quite difference. S-form is the sheet structure of layer upon layer, H-form looks like a hank of silk lines and B-form is the clubbed shape.     

EXTRACTION CHEMISTRY OF RARE EARTHS BY MONO-ALKYL ISOPROPYLPHOSPHONATES

The influence of chemical structure of ester alkyl group of mono-alkyl isopropylphosphonates on the extraction behaviours of rare earth has been studied. The mono-alkyl isopropylphosphonate bearing β-substituted ester alkyl group shows high K_(ex) value, which is evidently depressed, usually in two orders of magnitude, by introducing a branch chain on the α-position of the ester alkyl group. The steric effect of ligand is usually enhanced due to the characteristic lanthanide contraction.z2The extraction chemistry of rare earths by mono-amylnonyl isopropylphosphonates (MANPP) was studied in detail The thermodynamic function was estimated and the "tetrad effect" between K_(ex) value or △G value and atomic number was observed. In addition, the composition and structure of the coordinated compound was studied. As demonstrated by the experimental data, the extractive separation of Sm and Nd by MANPP in chloride solution was better than that in nitrate system.     

Studies on the Hydrosilation of Aromatic Aldehydes

The dependence of reactivity on molecular structure in hydro-silation of aromatic aldehydes catalyzed by (PPh3)3 RhCl was studied by “IN SITU” FT-IR technique and a plausible mechanism was proposed.The results show that: (1) Model reaction Ⅰ, Ⅱ and Ⅲ are all characterized by an induction period; (2) The reaction constant of model reaction Ⅰ is +1.57, so the rare of reaction Ⅰ is increased by the electron-withdrawing groups; (3) The rate of model reaction Ⅲ decreases when the size of R1 becomes larger; (4) The reaction constant of model reaction Ⅲ is -0. 50, so the rate of it is increased by electron-donating groups.     

新金刚石稳定性及晶体结构模型的研究

利用碳黑催化法制备了新金刚石粉末, 并通过粉末X射线衍射(XRD)对不同时效处理后的新金刚石样品进行表征. 结果表明, 新金刚石是一种亚稳态的相, 在室温下, 随着放置时间的推移其晶体结构发生变化. 根据XRD分析和模拟的XRD图谱, 提出了用具有分数占位的“缺陷金刚石”模型来解释新金刚石结构随时间的变化规律. 在该模型中, 原子的占位数χ为0时, 为面心立方结构(FCC), χ为1时, 为金刚石结构. 密度泛函理论计算结果表明, 随χ的增加, 其结构的稳定性也增加. 可见, 新金刚石是由FCC碳向金刚石结构过渡的中间态结构.     

Matrix Effects in a Fluid Catalytic Cracking Catalyst Particle: Influence on Structure,Acidity, and Accessibility

Matrix effects in a fluid catalytic cracking (FCC) catalyst have been studied in terms of structure, accessibility, and acidity. An extensive characterization study into the structural and acidic properties of a FCC catalyst, its individual components (i.e., zeolite H-Y, binder (boehmite/silica) and kaolin clay), and two model FCC catalyst samples containing only two components (i.e., zeolite-binder and binder-clay) was performed at relevant conditions. This allowed the drawing of conclusions about the role of each individual component, describing their mutual physicochemical interactions, establishing structure-acidity relationships, and determining matrix effects in FCC catalyst materials. This has been made possible by using a wide variety of characterization techniques, including temperature-programmed desorption of ammonia, infrared spectroscopy in combination with CO as probe molecule, transmission electron microscopy, X-ray diffraction, Ar physisorption, and advanced nuclear magnetic resonance. By doing so it was, for example, revealed that a freshly prepared spray-dried FCC catalyst appears as a physical mixture of its individual components, but under typical riser reactor conditions, the interaction between zeolite H-Y and binder material is significant and mobile aluminum migrates and inserts from the binder into the defects of the zeolite framework, thereby creating additional Brønsted acid sites and restoring the framework structure.     

金属Ni熔化前后结构变化的分子动力学模拟

使用Tight-binding势函数, 对FCC-Ni升温熔化过程的结构变化进行了分子动力学模拟. 在定压条件下模拟得到的Ni的熔点在1850 K与1900 K之间. 计算得到了体系在各温度下的径向分布函数和配位数分布等静态结构信息以及动力学性质. 计算得出的液体Ni的扩散系数在1900 K时约为5.02×10−9 m2•s−1, 与实验数据相符. 对液态体系中FCC短程有序结构可能发生的畸变以及由此导致的H-A键型变化进行了分析, 结合配位体构型搜索和键对分析方法计算了各温度下不同短程有序结构的分布. 计算表明, Ni在熔化之后仍保留有部分晶态短程结构, 但发生了较大的畸变, 同时液态中有少量的缺陷二十面体结构存在. 而液体Ni中大多数的配位体的几何构型介于FCC与缺陷二十面体之间.     

以催化油浆为增孔剂的MCM-41介孔分子筛的合成

采用阳离子表面活性剂十六烷基三甲基溴化铵为模板剂、正硅酸乙酯为硅源、硫酸铝为铝源，水热合成了以甲苯溶解的催化油浆为添加剂的MCM-41介孔分子筛，通过XRD、N2吸附脱附、TG-DTA、SEM等测试手段对合成样品进行了表征，重点研究了在甲苯/催化油浆=1∶1和2∶1（质量比）两个剂油比下分子筛结晶度、晶胞参数、BET表面积、平均孔径以及孔容等结构性质随催化油浆添加量的变化规律，并对合成机理进行了解释。结果表明，当剂油比为1∶1时，分子筛的结晶度和晶胞参数随催化油浆添加量的变化呈现先增加后减小趋势，当noil/nCTMAB=0.34时，其晶胞参数最大可以达到5.95 nm；当剂油比为2∶1时，随添加剂量的增加，分子筛结晶度降低，BET表面积成先增大后减小，而孔容和平均孔径呈逐渐增加趋势。当noil/nCTMAB＝0.15时，MCM-41的BET表面积可达1163.7m2·g-1，孔容可达到1.34cm3·g-1，平均孔径为4.34 nm。     

催化裂化汽油中类型硫含量分布

利用催化裂化汽油中各类硫化物的系统分析方法,对催化裂化(FCC)汽油和重油催化裂化(RFCC)汽油中各类型硫进行了分析测定,碱洗后FCC汽油和RFCC汽油中类型硫的布规律为:硫醇硫和二硫化物硫的含量较少,硫醚硫含量中等,而噻吩类硫的含量最多,占总硫含量的60%以上.     

多产低碳烯烃及柴油用分子筛的设计

目前,催化裂化的原料大多是蜡油和减压渣油的混合油,或全部的常压渣油 .其相对分子量范围很宽,组成十分复杂 .为了分别对待大小不同的分子和不同碳氢比化合物的裂化性能,现代催化裂化催化剂应具有梯度孔结构与梯度酸中心的优化结构配置 .而目前催化裂化的主导分子筛 USY二次孔含量还不能满足原料油日趋变重的需求,并且滞留在分子筛孔 /笼内的非骨架铝限制了其选择性的进一步提高,因此有必要对其结构进一步修饰 .　　本研究在 USY基础上合成新的催化裂化多产低碳烯烃和柴油用分子筛催化剂 .新型 USY基分子筛从晶体结构、孔容及孔…     

FCC油浆抽提分离产物结构组成分析

以切尾FCC油浆为原料，采用DMF和反抽提剂的复配溶剂进行抽提分离，对FCC油浆及其抽提产物的物性和组成进行了分析表征。结果表明，复配溶剂可以较好地将FCC油浆分离成以芳香烃为主的抽出相和以饱和结构为主的抽余相，在抽出油收率为58.5%时，抽出油芳香分含量80.5%，芳碳率为73.82%，所含芳烃以二环、三环和四环为主，可以作为橡胶填充油和增塑剂等的原料；抽余油饱和分含量高达90%以上，芳碳率只有2.38%，基本不含杂原子，可以作为优良的催化裂化原料。溶剂抽提可以使低附加值的FCC油浆得到较好的利用。     

Crystallization of Liquid Gold Nanoparticles by Molecular Dynamics Simulation

Molecular dynamics simulation of the crystallization behavior of liquid gold (Au) nanoparticles, with 1, 2, 3, 4, 5 and 6 nm in diameter, on cooling has been carried out based on the embedded-atom-method potential. With decreasing cooling time, the final structure of the particle changes from amorphous to crystalline structure. We showed that the structure of the fully crystallized particle is polycrystalline face-centered cubic (FCC). The FCC structure of the gold nanoparticle is proved energetically the most stable form. And the final structure of nanoparticles is affected by cooling time and size of nanoparticles. We also showed that the melting point of particles is affected by size of nanoparticles.     

催化裂化生焦反应集总动力学模型的研究

催化裂化生焦反应集总动力学模型的研究任杰（抚顺石油学院石油化工系，抚顺１１３００１）关键词催化裂化，生焦，集总动力学，动力学模型在催化裂化反应过程中，催化剂因结焦而迅速失活．催化剂结焦量对催化剂再生和装置的热平衡影响很大，因此建立生焦动力学模型对指导...     

Observation of Non‐FCC Copper in Alkynyl‐Protected Cu53 Nanoclusters

The only feasible access to non‐face‐centered cubic (FCC) copper was by physical vapor deposition under high vacuum. Now, non‐FCC copper is observed in a series of alkynyl‐protected Cu₅₃ nanoclusters (NCs) obtained from solution‐phase synthesis. Determined by single‐crystal X‐ray crystallography, the structures of Cu₅₃(C≡CPhPh)₉(dppp)₆Cl₃(NO₃)₉ and its two derivatives reveal an ABABC stacking sequence involving 41 Cu atoms. It can be regarded as a mixed FCC and HCP structure, which gives strong evidence that Cu can be arranged in non‐FCC lattice at ambient conditions when proper ligands are provided. Characterization methods including X‐ray absorption fine structure, XPS, ESI‐MS, UV/Vis, Auger spectroscopy, and DFT calculations were carried out. Cu^II was shown to successively coordinate with introduced ligands and changed to Cu^I after bonding with phosphine. The following addition of NaBH₄ and the aging step further reduced it to the Cu₅₃ NC.