Interfacial characterization of resistance spot welded joint of steel and aluminum alloy

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现代材料分析方法(英文)

Characterization techniques:(A) XPS (X-ray photoelectron spectroscopy):Hydrothermally deposited epitaxial thin films are characterized by XPS to retrieve useful information like composition, chemical structure and local arrangement of atoms that make up few layers of surface of film and also the interfacial layer between the film and substrate.X-ray photoelectron spectroscopy (XPS) was developed in the mid –1960s by Kai Siegnahm and his research group at the University of Uppsala, Sweden.Surface analysis by XPS involves irradiating a solid in vacuum with monoenergetic soft x-rays and analyzing the emitted electrons by energy. The spectrum is obtained as a plot of the number of detected electrons per energy interval versus their kinetic energy. The principle on which the XPS technique is based can explained with the help of figure 1 as shown below. [27]Figure 1. An energy level diagram showing the physical basis of XPS technique.The energy carried by an incoming X-ray photon is absorbed by the target atom, raising it into excited state from which it relaxes by the emission of a photoelectron. Mg Kα(1253.6eV) or Al Kα (1486.6 eV) x-rays are generally used as a source of monoenergetic soft x-rays. These photons have limited penetrating power in a solid on the order of 1-10 micrometers. They interact with atoms in the surface region, causing electrons to be emitted by the photoelectric effect. The emitted electrons have measured kinetic energies given by:KE=hγ-BE -φsWhere hγ is the energy of the photon, BE is the binding energy of the atomic orbital from which the electron originates and φs is the spectrometer work function. The binding energy may be regarded as the energy difference between the initial and final states after the photoelectron has left the atom. Because there are a variety of possible final states of the ions from each type of atom, there is corresponding variety of kinetic energies of the emitted electrons. Photoelectrons are emitted from all energy levels of the target atom and hence the electron energy spectrum is characteristic of the emitting atom type and may be thought as its XPS fingerprint. Each element has unique spectrum .The spectrum from a mixture of elements is approximately the sum of peaks of the individual constituents. Because the mean free path of electrons in the solids is very small, the detected electrons originate from only the top few atomic layers making XPS a unique surface sensitive technique for chemical analysis. Quantitative data can be obtained from peak heights or peak areas and identification of chemical states often can be made from exact measurement of peak positions and separations as well from certain spectral features.The line lengths indicate the relative probabilities of the various ionization processes. The p,d and f levels split upon ionization leading to vacancies in the p1/2,p3/2,d3/2,d5/2,f5/2 and f7/2.The spin orbit splitting ratio is 1:2 for p levels ,2:3 for d levels and 3:4 for f levels .Because each element has a unique set of binding energies, XPS can be used to identify and determine the concentration of the elements in the surface. Variations in the elemental binding energies (the chemical shifts) arise from the differences in the chemical potential and polarizibilty of compounds. These chemical shifts can be analyzed to identify the chemical state of the materials being analyzed.The electrons leaving sample are detected by an electron spectrometer according to their kinetic energy. The analyzer is usually operated as an energy window, referred to as pass energy. To maintain a constant energy resolution, the pass energy is fixed. Incoming electrons are adjusted the pass energy before entering the energy analyzer. Scanning for different energies is accomplished by applying a variable electrostatic field before the analyzer. This retardation voltage may be varied from zero upto and beyond the photon energy. Electrons are detected as discrete events, and the number of electrons for the given detection time. And energy is stored and displayed.In general, the interpretation of the XPS spectrum is most readily accomplished first by identifying the lines that almost always present (specifically those of C and O), then by identifying major lines and associated weaker lines.(B) Auger electron spectroscopy:Auger electron spectroscopy is a very useful technique in elemental characterization of thin films. In the current project this technique has been utilized not only for elemental compositional analysis but also for understanding nucleation and growth mechanism. Auger electron effect is named after the French physicist Pierre Auger who described the process involved in 1925.Auger is process is bit more complicated than the XPS process.The Auger process occurs in three stages. First one being atomic ionization. Second being electron emission (Auger emission) and third being analysis of emitted auger electrons .The source of radiation used is electrons that strike in the range of 2 to 10 kev. The interatomic process resulting in the production of an Auger electron is shown in figure 2 below.Figure 2 showing the interatomic process resulting in production of the Auger electrons. One electron falls a higher level to fill an initial core hole in the k-shell and the energy liberated in this process is given to second electron ,fraction of this energy is retained by auger electron as kinetic energy.X-ray nomenclature is used for the energy levels involved and the auger electron is described as originating from for example ,an ABC auger transition where A is the level of the original core hole,B is the level from which core hole was filled and C is the level from which auger electron was emitted. In above figure 2 shown above the auger transition is described as L3M1M2, 3.The calculation of energies of the lines in the Auger electron spectrum is complicated by the fact that emission occurs from an atom in an excited state and consequently the energies of the levels involved are difficult to define precisely.Each element in a sample being studied gives rise to characteristic spectrum of peaks at various kinetic energies. Area generally scanned is 1 mm2.To understand the variation in the concentration with the distance from the surface depth profiling can also be carried out. For depth profiling the surface has to be etched away by using argon beam.The principle advantage that AES hold over XPS is that the source of excitation in case of AES is electrons which allows it to take a spectra from micro-regions as small as 100 nm diameters or less instead of averaging over the whole of the surface of the sample as is done generally in XPS.(C) Atomic force Microscope:Atomic Force Microscope (AFM ) is being used to solve processing and materials problems in a wide range of technologies affecting the electronics, telecommunications, biological, chemical, automotive, aerospace, and energy industries. The materials being investigating include thin and thick film coatings, ceramics, composites, glasses, synthetic and biological membranes, metals, polymers, and semiconductors.In the current work AFM was used to understand the nucleation and growth mechanism of the epitaxial thin films and to understand the surface morphology of totally grown films in terms of surface coverage and surface roughness.In the fall of 1985 Gerd Binnig and Christoph Gerber used the cantilever to examine insulating surfaces. A small hook at the end of the cantilever was pressed against the surface while the sample was scanned beneath the tip. The force between tip and sample was measured by tracking the deflection of the cantilever. This was done by monitoring the tunneling current to a second tip positioned above the cantilever. They were able to delineate lateral features as small as 300 Å. This is the way force microscope was developed. Albrecht, a fresh graduate student, who fabricated the first silicon microcantilever and measured the atomic structure of boron nitride. The tip-cantilever assembly typically is microfabricated from Si or Si3N4. The force between the tip and the sample surface is very small, usually less than 10-9 N.According to the interaction of the tip and the sample surface, the AFM is classified as repulsive or Contact mode and attractive or Noncontact mode. In contact mode the topography is measured by sliding the probe tip across the sample surface. In noncontact mode, topography is measured by sensing Van de Waals forces between the surface and probe tip. Held above the surface. The tapping mode which has now become more popular measures topography by tapping the surface with an oscillating probe tip which eliminates shear forces which can damage soft samples and reduce image resolution. 1. Laser2. Mirror3. Photo detector4. Amplifier5. Register6. Sample7. Probe8. CantileverFigure 3 showing a schematic diagram of the principle of AFM.Compared with Optical Interferometric Microscope (optical profiles), the AFM provides unambiguous measurement of step heights, independent of reflectivity differences between materials. Compared with Scanning Electron Microscope, AFM provides extraordinary topographic contrast direct height measurements and unobscured views of surface features (no coating is necessary). One of the advantages of the technique being that it can be applied to insulating samples as well. Compared with Transmission Electron Microscopes, three dimensional AFM images are obtained without expensive sample preparation and yield far more complete information than the two dimensional profiles available from cross-sectioned samples.(D) Fourier Transform Infrared Spectroscopy:Infrared spectroscopy is widely used chemical analysis tool which in addition to providing information on chemical structures also can give quantitative information such as concentration of molecules in a sample.The development in FTIR started with use of Michelson interferometer an optical device invented in 1880 by Albert Abraham Michelson. After many years of difficultiesin working out with time consuming calculations required for conversion intereferogram into spectrum, the first FTIR was manufactured by the Digilab in Cambridge Massachusetts in 1960s .These FTIR machines stared using computers for calculating fourier transforms faster.The set up consists of a source, a sample and a detector and it is possible to send all the source energy through an interferometer and onto the sample. In every scan, all source radiation gets to the sample. The interferometer is a fundamentally different piece of equipment than a monochromater. The light passes through a beamsplitter, which sends the light in two directions at right angles. One beam goes to a stationary mirror then back to the beamsplitter. The other goes to a moving mirror. The motion of the mirror makes the total path length variable versus that taken by the stationary-mirror beam. When the two meet up again at the beamsplitter, they recombine, but the difference in path lengths creates constructive and destructive interference: an interferogram:The recombined beam passes through the sample. The sample absorbs all the different wavelengths characteristic of its spectrum, and this subtracts specific wavelengths from the interferogram. The detector reports variation in energy versus time for all wavelengths simultaneously. A laser beam is superimposed to provide a reference for the instrument operation.Energy versus time was an odd way to record a spectrum, until the point it was recognized that there is reciprocal relationship between time and frequency. A Fourier transform allows to convert an intensity-vs.-time spectrum into an intensity-vs.-frequency spectrum.The advantages of FTIR are that all of the source energy gets to the sample, improving the inherent signal-to-noise ratio. Resolution is limited by the design of the interferometer. The longer the path of the moving mirror, the higher the resolution.One minor drawback is that the FT instrument is inherently a single-beam instrument and the result is that IR-active atmospheric components (CO2, H2O) appear in the spectrum. Usually, a "Background" spectrum is run, and then automatically subtracted from every spectrum.(E) Scanning Electron Microscopy:Scanning electron microscopy is one the most versatile characterization techniques that can give detailed information interms of topography, morphology, composition and crystallography. This has made it widely useful in thin film characterization.The scanning electron microscope is similar to its optical counterparts except that it uses focused beam of electrons instead of light to image the specimen to gain information about the structure and composition.A stream electron is accelerated towards positive electrical potential. This stream is confined and focused using metal apertures and magnetic lenses into a thin, focused, monochromatic beam. This beam is focused onto the sample using a magnetic lens. Interactions occur inside the irradiated sample, affecting the electron beam. These interactions and effects are detected and transformed into an image. The electron detector collects the electrons and then image is created. Scanning with SEM is accomplished bytwo pairs of electromagnetic coils located within the objective lens, one pair deflects the beam in x-direction across the sample and the other pair deflects it in the y direction. Scanning is controlled by applying an electric signal to one pair of scan coils such that the electron beam strikes the sample to one side of theFigure 4 Schematic view of a SEM instrument.center axis of the lens system. By varying the electrical signal to this pair of coils as a function of time, the electron beam is moved in a straight line across the sample and then returned to its original position. Thus by rapidly moving the beam the entire sample surface can be irradiated with the electron beam. The output signal consists of backscattered and secondary electrons which generally serve as basis of scanning electron microscope and whereas the x-ray emission serves as the basis of the energy dispersive spectroscopy as shown in figure 4.Figure 5.Schematic presentation of the interaction of the electron with the sample.Energy dispersive spectroscopy is analytical method which is used in determination of elemental composition of the specimen.EDS uses the electrons generated characteristic x-radiation to determine elemental composition. The SEM/EDS combination is a powerful tool in inorganic microanalysis, providing the chemical composition of volumes as small as 3 m3.(F) Transmission Electron microscopy:Transmission electron microscopy was used to analyze the interface between the BaTiO3 on SrTiO3 single crystals.For TEM specimen must be specially prepared to thicknesses which allow electrons to transmit through the sample, much like light is transmitted through materials in conventional optical microscopy. Because the wavelength of electrons is much smaller than that of light, the optimal resolution attainable for TEM images is many orders of magnitude better than that from a light microscope. Thus, TEMs can reveal the finest details of internal structure - in some cases as small as individual atoms. Magnifications of 350,000 times can be routinely obtained for many materials, whilst in special circumstances; atoms can be imaged at magnifications greater than 15 million timesThe energy of the electrons in the TEM determine the relative degree of penetration of electrons in a specific sample, or alternatively, influence the thickness of material from which useful information may be obtained.Cross-sectional specimens for TEM observation of the interface between the film and the substrate were prepared by conventional techniques employing mechanical polishing, dimpling and ion beam milling.TEM column is shown in figure 6 consists of gun chamber on the top to the camera at the bottom everything is placed under vacuum.Figure 6. Main components of TEM system. [28]At the top of the TEM column is the filament assembly, which is connected to thehigh voltage supply by insulated cable. In standard TEM, normal accelerating voltagesranges from 20,000 to 100,000V.Intermediate-voltage and high voltage TEMs may use accelerating voltages of 200,000 V to 1000000 V.The higher the accelerating voltage, the greater the theoretical resolution. Below the filament tip and above it the anode is a beam volume called crossover. In this area of the filament chamber, the electron beam volume iscondensed to its highest density. There are more electrons per unit area at the cross over than at any other place in the microscope. Crossover is the effective electron source for image formation. In a TEM, the diameter of the electron beam at crossover is approximately 50 μm.The anode or positively charged plate, is below the filament assembly.Electron beam then travels to the condenser –lens system.TEMs has two condensers lenses. Condenser system lens system controls electron illumination on the specimen and on the viewing screen for such functions as viewing, focusing and photography. Condenserlenses are fitted with apertures which are usually small platinum disks or molybdenum strips with holes of various sizes ranging from 100 to 400 μm and it protects specimen from too many stray electrons which can contribute to excessive heat and limit X-ray production farther down the columnObjective lens is the first magnifying lens and the specimen is inserted into the objective lens, which must be designed so that the specimen can be moved in both X and Y directions and have tilting and rotating capabilities. As the electron beam interacts with the specimen, a number of signals useful in the formation of the TEM image occur: absorption, diffraction, elastic scattering and inelastic scattering.(H) X-ray Diffraction (XRD):X-ray diffraction is the most commonly known technique which I used to determination of the phase formed in films and also to assess texture and crystallinity.X-rays were discovered in 1895 by the German physicist Wilhelm Conrad Röntgen - in some languages x-rays are called Röntgen-rays - and x-ray diffraction was discovered in 1912.The X-rays used in diffraction experiments all have a wavelength of 0.5-2.5 Å. The intensity of a beam of x-rays is the rate of transport of energy flow through a unit area perpendicular to the direction of propagation. To produce x-rays, a source of electrons, a high accelerating voltage and a target are needed. To get the voltage, the metal target is grounded and a cathode is at 30-50 kV. To get the electrons a metal filament is resistively heated (the tube is called a filament tube). The filament current is 3-5 amps. The cathode and the filament is one and the same thing and surrounding the target and the filament is an air evacuated envelope.The electrons from the filament are accelerated towards the target. They bombard the target in a rectangular shaped area called the focal spot. From there the x-rays are emitted in all directions. The walls of the tube are impenetrable for the x-rays except where beryllium windows are inserted. Beryllium has a very low absorption coefficient for the x-rays.The amount of x-rays produced depends on the number of electrons emitted and their energy when they reach the target. The number of electrons in turn depends on the filament temperature, and thus the filament current. The current of electrons from the filament to the target is measurable and usually 25-55 mA. This current can be chosen freely as a feedback loop will feed the filament with the current needed. The energy ofthe electrons depend on the accelerating voltage. Thus the total intensity emitted by thex-ray tube depends on both the operating voltage and the tube current.In general, diffraction is possible when the length of the wave is of the same order of magnitude as the distance between the regularly spaced scattering objectsTwo scattered rays are in phase, if their path difference is equal to a whole number n of wavelengths. Scattered rays emerging from a plane surface as a result of a beam incident on that surface, have a path difference equal to a whole number of wavelengths, if n l = 2 d' sinq (The Bragg Law),where d' is the distance between the diffracting planes in the crystal and q is the angle between the incident beam and the surface. n is the order of reflection and n can be any integral number as long as sin q < 1. n is also equal to the number of wavelengths in the path difference of two rays scattered from adjacent planes (e.g. If n = 2 then a ray scattered from one plane will have a path that is two wavelengths shorter than a ray scattered from a deeper lying neighbor plane).The basis for phase analysis is that the crystal of a certain phase will have interatomic distances peculiar to that phase and these different distances will cause a series of reflections as the detector are shifted through 2theta.Two phases can have similar or almost similar structures and hence interatomic distances. This makes identifying phases in an unknown sample very difficult, but knowing what elements are present in the sample will narrow the possibilities down quite a bit. Also crystallite size using XRD .X-ray pole figure measurements are used to characterize the film with respect to any preferred orientation with which growth has taken place. Rocking curve is another application to characterize the film with respect to its quality ofcrystallinity comparing to the single crystals or polycrystalline materials.。

Materials Characterization

Materials Characterization Materials characterization is a crucial aspect of scientific research and development. It involves the study and analysis of the physical, chemical, and mechanical properties of materials. By understanding these properties, scientists and engineers can design materials with specific characteristics and improve existing materials for various applications. In this response, I will discuss the importance of materials characterization from multiple perspectives, including scientific, engineering, and industrial. From a scientific perspective, materials characterization plays a vital role in advancing our understanding of the fundamental properties of matter. By studying the structure and composition of materials at the atomic and molecular level, scientists can gain insights into the behavior and properties of different materials. For example, techniques such as X-ray diffraction and electron microscopy can provide information about the crystal structure and morphology of materials, helping scientists understand how these factors influence material properties. This knowledge is essential for developing new materials with tailored properties for specific applications. From an engineering perspective, materials characterization is essential for designing and selecting materials that can withstand specific conditions and perform optimally in different applications. For instance, in the aerospace industry, materials used in aircraft components need to have high strength, low weight, and resistance to high temperatures. By characterizing the mechanical properties of different materials, engineers can determine which materials are suitable for specific applications. This ensures the safety and reliability of engineering structures and devices. From an industrial perspective, materials characterization iscrucial for quality control and product development. Manufacturers need to ensure that their materials meet certain specifications and standards to guarantee the performance and durability of their products. By characterizing the properties of materials, such as hardness, tensile strength, and corrosion resistance, manufacturers can assess the suitability of materials for different applications. This helps in improving product quality and reducing the risk of failure or malfunction. Moreover, materials characterization also plays a significant role in the field of nanotechnology. As materials are miniaturized to the nanoscale,their properties can change drastically. Therefore, it is essential to characterize the size, shape, and composition of nanoparticles accurately. This information is crucial for understanding their behavior and interactions with other materials. Nanoparticles find applications in various fields, such as electronics, medicine, and energy, and their properties need to be thoroughly characterized to ensure their safe and effective use. In addition to scientific, engineering, and industrial perspectives, materials characterization also has societal implications. For instance, the development of new materials with improved properties can lead to technological advancements that benefit society. Materials with higher strength and lighter weight can contribute to the development of more fuel-efficient vehicles, reducing carbon emissions and combating climate change. Similarly, the development of materials with enhanced electrical conductivity can lead to the production of more efficient electronic devices, improving communication and connectivity. In conclusion, materials characterization is of utmost importance from multiple perspectives. It enables scientists to understand the fundamental properties of matter, engineers to design and select materials for specific applications, and manufacturers to ensure product quality. Moreover, materials characterization plays a significant role in the field of nanotechnology and has societal implications, contributing to technological advancements and addressing global challenges. Therefore, continued research and development in materials characterization are crucial for the progress of science, engineering, and society as a whole.。

原位表征,co2还原,研究进展

原位表征,co2还原,研究进展英文回答：In situ characterization of CO2 reduction has emerged as a powerful tool to elucidate the complex mechanisms and dynamics of this promising electrochemical process. By utilizing advanced analytical techniques, researchers can probe the surface and interfacial phenomena that govern the catalytic activity and selectivity of CO2 reduction catalysts. This article reviews the recent progress in in situ characterization of CO2 reduction, highlighting various experimental approaches and their contributions to our understanding of the underlying mechanisms.Operando X-ray absorption spectroscopy (XAS) has been widely employed to identify and quantify the active species and intermediates involved in CO2 reduction. XAS provides information on the oxidation state, coordination environment, and electronic structure of metal centers, enabling researchers to track the evolution of the catalystduring the reaction. In situ X-ray diffraction (XRD) can complement XAS by providing structural information, such as crystal structure, phase transitions, and surface reconstructions. These techniques together provide a comprehensive picture of the catalyst's structure and dynamics under reaction conditions.In situ scanning tunneling microscopy (STM) and atomic force microscopy (AFM) offer atomic-scale imaging of the catalyst surface, revealing the morphology, defects, and surface intermediates. These techniques can probe the surface reactivity and uncover the mechanisms of CO2 activation and product formation. In situ electrochemical microscopy (ECM) combines electrochemical measurements with optical microscopy, allowing for real-time visualization of the electrochemical processes occurring at the catalyst surface. This approach provides insights into the spatial distribution of catalytic activity and the influence of local surface features.Electrochemical impedance spectroscopy (EIS) and other electrochemical techniques provide complementaryinformation about the electrical properties of the catalyst and the electrode-electrolyte interface. These techniques can probe the charge transfer kinetics, double-layer capacitance, and other electrochemical parameters, which are crucial for understanding the efficiency andselectivity of CO2 reduction.In addition to these experimental approaches, theoretical modeling and simulations have played an important role in understanding the mechanisms of CO2 reduction. Density functional theory (DFT) calculations can provide insights into the energetics and reaction pathways of CO2 reduction, complementing the experimental observations.By combining these in situ characterization techniques with theoretical modeling, researchers have madesignificant progress in understanding the complex mechanisms of CO2 reduction. This knowledge has guided the development of more efficient and selective catalysts, paving the way for the practical implementation of CO2 reduction technologies.中文回答：原位表征在 CO2 还原研究中的进展。

pp的论文

Characterization of the interfacial properties of modified Polypropylene改进的聚丙烯界面属性的描述JochenFrank,Frank Simon and Franz-Josef Schmitt*Institute of Polymer Research Dresden,PO Box 120411,D-01005 Dresden,Germany.E-mail:schmfj@ipfdd.deReceived 26th April 1999,Accepted 25th June 1999The interfacial Properties of a rubber blended polypropylene were investigated by the combination of complementary techniques in order to characterize the effects of different surfacetreatments.The wettability was investigated by contact angle measurements with water,streaming potential measurements indicated the Bronsted acidity/basicity of the surfaces,and X-ray photoelectron spectroscopy(XPS)identified the chemical elements,which were incorporated by the various treatments.The topography and the roughness of the samples were quantitatively analyzed by scanning force microscopy(SFM).Direct force measurements showed the possibility of changing the sign of the surface charge by choosing suitable buffer solutions,leading to attraction and repulsion to the Si3N4 tip,respectively.In the case of technical-type polymer samples used in this study,direct force measurements are in exact agreement with the streaming potential measurements and offer avaluable tool for interface characterization.通过化合反应，聚丙烯混合的橡胶界面性能被研究是为了描述不同界面方法的影响。

2题名+单位英文名

当有介词by时, 应保留investigation 之类的词。
Investigation of phase behavior of polymer blends by thermal methods. A study of rate constants for two-phase electron-transfer reaction by A.C. impedance → A.C. impedance study of rate constants for two-phase electron-transfer reaction
The synthesis of a novel alcoholsoluble polyamide resin → Synthesis of a novel alcoholsoluble polyamide resin
• Avoid nonquantitative , meaningless words like “rapid” and “new”
“Speciation”(鉴别分类)含义已经包括物质的各种化学形态、形态分析。 “Chemical”、“Analysis”应删去。
举例
在三个升温速率下用热天平研究煤的热解及其反应动力学 → 煤的热解及其反应动力学 PES/PC 共混体系的研究 → PES/PC 共混体系的力学性能； PES/PC 共混体系的相容性与力学性能
• In most cases, omit “the” at beginning of the title
The microstructure of microcrystalline cellulose → Microsபைடு நூலகம்ructure of microcrystalline cellulose

中英文催化剂的制备与表征(catalysis and physical properties)

Introduction to this subject
➢ Preparation, characterization and application of a catalyst is crucial to innovate a novel catalyst.是发明一个新催化剂的关键。
➢ Catalyst is usually not the same with other chemicals, especially pure chemicals.催化剂一般与其他化学品一样，特别是纯化学品。
Definition of Catalyst
➢ Ostwald (德国）的观点催化剂是一种能够改变化学反应的速度，而它本身又不参与最终产物的物质。（流行）
➢ IUPAC定义：催化剂能够加速反应速率而不改变反应的标准Gibbs自有焓变化。
➢ 国内新近定义催化时加速反应速度、控制反应方向或产物构成，而不影响化学平衡的一类作用。起这种作用的物质称为催化剂，它不在主反应的化学计量式中反映出来，即在反应中不被消耗。
Ideal surface is not perfect
理想的表面是不完美的
扭结
阶梯空位
阶梯位
台阶吸附的原子台阶空位
球的堆积模型表示不完美表面
Heterogeneous Catalyst
* Metals (Transition metals, IB metals);金属
Fe Co Ni Ru Rh Cu Ag Au Pd Os Ir Pt
Mechanism for heterogeneous Catalysis
Heterogeneous Catalysis
➢ Heterogeneous mechanism is difficult to investigated in the laboratory. Disappearance of reactants and appearance of products are easily followed, but important features such as the rates and energetic of adsorption, structure of active sites, the nature of active intermediates, require separate experimentation using a constantly changing arsenal of techniques. 非均相机理的实验室研究非常困难。反应物的消耗和产物的生成比较容易追踪，但许多重要的因素比如速度和吸附能，活性位结构、活性中间体特点等需要通过大量的单因素实验来得出。

合材料的拉伸损伤演变过程和微观结构特征

梅辉等：2D C/SiC复合材料的拉伸损伤演变过程和微观结构特征· 137 ·第35卷第2期2维C/SiC复合材料的拉伸损伤演变过程和微观结构特征梅辉，成来飞，张立同，徐永东，孟志新，刘持栋(西北工业大学，超高温结构复合材料国防科技重点实验室，西安 710072)摘要：通过单向拉伸和分段式加载–卸载实验，研究了二维编织C/SiC复合材料的宏观力学特性和损伤的变化过程。

用扫描电镜对样品进行微观结构分析，并监测了载荷作用下复合材料的声发射行为。

结果表明：在拉伸应力低于50MPa时，复合材料的应力–应变为线弹性；随着应力的增加，材料模量减小，非弹性应变变大，复合材料的应力–应变行为表现为非线性直至断裂。

复合材料的平均断裂强度和断裂应变分别为234.26MPa和0.6%。

拉伸破坏损伤表现为：基体开裂，横向纤维束开裂，界面层脱粘，纤维断裂，层间剥离和纤维束断裂。

损伤累积后最终导致复合材料交叉编织节点处纤维束逐层断裂和拔出，形成斜口断裂和平口断裂。

关键词：陶瓷基复合材料；碳纤维/碳化硅复合材料；力学性能；微结构中图分类号：TB332文献标识码：A文章编号：0454–5648(2007)02–0137–07DAMAGE EVOLUTION AND MICROSTRUCTURAL CHARACTERIZATION OF ACROSS-WOVEN C/SiC COMPOSITE UNDER TENSILE LOADINGMEI Hui，CHENG Laifei，ZHANG Litong，XU Yongdong，MENG Zhixin，LIU Chidong(National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi′an 710072, China)Abstract: The damage evolution and the associated mechanical response of a 2 dimensional C/SiC composite were investigated under monotonic and stepwise incremental loadings and unloadings. The microstructures of the samples were observed by scanning electron microscopy and the damage behavior under mechanical loading was monitored by the acoustic emission technique. The results show that the stress-strain of the composite is linear at stress below 50MPa. The modulus of the material decreases and the inelastic strain increases with the increase of tension stress, and the composite exhibits a largely non-linear stress-strain behavior up to rupture. The mean fracture strength and failure strain of the composite are 234.26MPa and 0.6%, respectively. The tensile damage behavior in-volves: matrix microcracking, transverse bundle cracking, interfacial debonding, fiber fracture, ply delamination and bundle splitting. The damage accumulation eventually results in splitting and pull-outs of the fibers at the crossovers between the bundles, leading to two major rupture modes of the oblique and plain sections.Key words: ceramic matrix composites; carbon fiber/silicon carbide composite; mechanical properties; microstructure连续碳纤维增强碳化硅陶瓷基复合材料(carbon fiber reinforced silicon carbide, C/SiC)具有高强度、高硬度、耐高温、低密度等一系列优异性能，已成为航空航天领域极具发展前景的新一代高温热结构材料[1]。

交流阻抗分析

In this paper, ac impedance is measured on different ﬂux types and compared with SIR results. Using standard circuit analysis, equivalent inductance-capacitance-resistance circuits are constructed to invesnts and their concentration. Using this approach, speciﬁc features from the impedance spectrum can be attributed to electrochemical parameters, such as the doublelayer capacitance and the charge-transfer resistance. The dominant conduction processes can be estimated by ac impedance spectrum analysis, and it is shown that dendrite formation can be predicted.
Ling Chunxian Zouz and Christopher Hunt
National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
The reliability impact of ﬂux residues on electronic assemblies has been traditionally evaluated using surface insulation resistance ͑SIR͒ measurement with dc voltages. An ac impedance technique has been investigated to provide detailed information on the conduction mechanisms and electrode reactions in the presence of ﬂux residues on electronic boards. By evaluating different ﬂuxes using a standard comb pattern the relative applicability of the ac impedance and SIR techniques has been made in terms of assessing the reliability of electronic boards. Impedance values at low frequencies, Ͻ1 Hz, are close to the SIR results and hence produce similar predictions of reliability. More importantly, the ac impedance spectrum can be used to predict dendrite formation, although the technique itself does not actually promote dendrites. The ac impedance method can distinguish between ionic solution resistance of the thin water layer and impedance from interfacial electrochemical processes. At low contamination levels the solution resistance, between the copper-comb electrodes, dominates the overall impedance. At high contamination levels the impedance from interfacial electrochemical processes becomes signiﬁcant and increases the potential of dendrite formation. This predictive capability could be developed into a nondestructive test method to provide a more detailed electrochemical characterization and indication of future reliability. © 2008 The Electrochemical Society. ͓DOI: 10.1149/1.3005563͔ All rights reserved.

三点弯疲劳英语

三点弯疲劳英语Three-Point Bending FatigueFatigue is a critical consideration in the design and analysis of engineering structures and components that are subjected to cyclic or repeated loading conditions. One of the most common experimental methods used to evaluate the fatigue behavior of materials is the three-point bending fatigue test. This test provides valuable information about the material's resistance to crack initiation and propagation under cyclic stresses.In a three-point bending fatigue test, a specimen is supported at two points and a cyclic load is applied at the midpoint of the specimen. The cyclic load induces alternating tensile and compressive stresses in the material, which can eventually lead to the initiation and growth of cracks. By monitoring the number of cycles required to cause failure, researchers can determine the material's fatigue life and establish S-N curves, which relate the stress amplitude to the number of cycles to failure.The three-point bending fatigue test is particularly useful for evaluating the fatigue behavior of materials that are subjected to bending stresses in service, such as beams, shafts, and structural members. The test can be performed on a variety of materials, including metals, polymers, and composites, and can be used to investigate the effects of different factors on fatigue life, such as stress amplitude, mean stress, surface finish, and environmental conditions.One of the key advantages of the three-point bending fatigue test is its simplicity and versatility. The test setup is relatively straightforward, and the specimen geometry is easy to fabricate. Additionally, the test can be performed on a wide range of specimen sizes, allowing for the evaluation of both small-scale laboratory specimens and larger-scale components.Despite its simplicity, the three-point bending fatigue test can provide valuable insights into the underlying mechanisms of fatigue failure. By analyzing the crack initiation and propagation behavior, researchers can gain a better understanding of the material's microstructural and mechanical properties that govern its fatigue resistance.For example, in the case of metallic materials, the three-point bending fatigue test can be used to investigate the role of grain size,crystal structure, and the presence of defects or inclusions on the material's fatigue life. Similarly, for polymer and composite materials, the test can be used to study the influence of fiber orientation, matrix properties, and interfacial bonding on the fatigue behavior.In addition to providing information about the material's fatigue life, the three-point bending fatigue test can also be used to evaluate the effects of various surface treatments and coatings on the material's resistance to fatigue failure. For instance, the test can be used to assess the effectiveness of shot peening, nitriding, or carburizing processes in improving the fatigue life of metal components.Furthermore, the three-point bending fatigue test can be coupled with advanced characterization techniques, such as digital image correlation (DIC) and acoustic emission monitoring, to gain a more detailed understanding of the deformation and damage mechanisms occurring during the fatigue process. These techniques can provide valuable insights into the localized strain distributions, crack initiation sites, and energy dissipation within the material.One of the challenges associated with the three-point bending fatigue test is the accurate measurement and control of the applied cyclic loads and displacements. Factors such as specimen alignment, load train stiffness, and the presence of friction or misalignment can all influence the stress and strain distributions within the specimen,which can ultimately affect the measured fatigue life.To address these challenges, researchers have developed various experimental setups and data analysis techniques to improve the reliability and repeatability of the three-point bending fatigue test. For example, the use of servo-hydraulic or electromechanical testing machines with precise load and displacement control, as well as the implementation of advanced data acquisition and signal processing methods, can help to minimize the impact of these experimental factors.Additionally, the development of computational models, such as finite element analysis (FEA), can provide valuable insights into the stress and strain distributions within the specimen during the three-point bending fatigue test. These models can be used to optimize the test setup, interpret the experimental data, and predict the fatigue behavior of the material under different loading conditions.In conclusion, the three-point bending fatigue test is a widely used and versatile experimental technique for evaluating the fatigue behavior of materials. By providing information about the material's resistance to crack initiation and propagation under cyclic bending stresses, this test can contribute to the design and development of more reliable and durable engineering structures and components. As research in this field continues to evolve, the three-point bendingfatigue test will remain an essential tool for understanding and predicting the fatigue performance of a wide range of materials.。

PCB油墨综述

PCB油墨综述曾鹏摘要：本文介绍了PCB制造过程中所用阻焊油墨的研究现状及其发展趋势，重点介绍了可喷墨打印阻焊油墨、柔性电路板用阻焊油墨、水溶性碱显影感光阻焊油墨和LED 封装用白色阻焊油墨的研究现状及趋势。

关键词：阻焊油墨；超支化树脂；喷墨打印；感光显影印制线路板(PCB)在生产过程中，为了提高焊接效率、避免不需要焊接的部位受到破坏，需要对这些部位用阻焊油墨加以保护，阻焊油墨经过丝网印刷、凹版印刷、喷墨打印的方法涂布在PCB表面，经过固化处理即可形成阻焊膜。

印制电路用阻焊油墨经过了四个阶段的发展，从早期的干膜型和热固性逐渐发展为紫外(UV)光固型，进而出现感光显影型阻焊油墨。

阻焊油墨的发展历程与设备工艺、焊接条件以及线路要求密不可分。

随着PCB进一步高密度化以及无铅焊接工艺的出现，对于稀释剂调节油墨黏度，使其满足喷墨打印黏阻焊油墨也提出了新的要求，如更高的分辨率、更细的线宽，以及更高的耐热温度等[1-5]。

本文按照阻焊油墨的实施工艺和方法，介绍了以喷墨打印为主要技术手段的加成法用阻焊油墨，兼有加成法工艺和减成法工艺的柔性电路板用阻焊油墨，以及目前硬板大量使用的传统感光显影型阻焊油墨的研究现状及存在的问题，也探讨了LED封装用高反射率的白色阻焊剂的研究进展，拓展了阻焊剂的应用领域，希望能对今后的工作有一定的指导作用。

1、低黏度可喷墨阻焊油墨随着电子工业的发展，一种采用加成法的全印制电子技术应运而生，加成法工艺具有节约材料、保护环境、简化工序等优点，目前被认为是未来电子行业发展的新趋势[6]。

但由于其采用喷墨打印作为主要技术手段，对油墨以及本体材料的性质有新的要求，主要表现为：(1)控制油墨黏度，使其保证能通过喷嘴连续喷出，防止其堵塞碰头；(2)控制固化反应速度，实现快速初固，防止油墨在基板因浸润而散开；(3)调节油墨触变性，确保打印线路质量及可重复性[7-10]。

对于低黏度阻焊油墨的研制，主要采用对传统阻焊材料的改性，辅以活性或非活性度要求。

2015年湘潭大学科学研究训练

科学研究训练
一、基本要求
二、学术论文写作三、专业文献查找
四、毕业论文注意事项
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科学研究训练
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一、基本要求
1、听二到三场学术报告 2、写两场学术报告的感想(关于理工科的) 3、归纳总结一篇本专业学术论文 (参考公开发
表的文章，但必须用自己的语言归纳，总结)
5、格式要符合科技论文的格式
6、2015年1月15日前学习委员交给我
3. Addresses(作者单位与联系地址） 4. Abstract(摘要) 6. Introduction(引言） 8. Conclusion(结论) 5. Key words(关键词) 7. Text (正文） 9. Acknowledgements(致谢）
10. Reference(参考文献） 11. Appendix(附录)
文集以英语作为语言工具。
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二、学术论文写作
1.公共英语
英语
2.文学英语 3. 科技英语 4.专业英语
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二、学术论文写作
1.Words 2. Sentence
3. Paper
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二、学术论文写作
Words 专业词汇大都借用常用词汇，且出现的频率低、词义专一、词义多源于希腊语和拉丁语、广泛使用缩略话、前后缀出现
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二、学术论文写作
2. Author
论文作者姓名写在论文标题的正下方中央处。第
一作者(担任论文主要工作、起决定作用的作者)的姓名
排在最前面。
可以在姓名的右上角标上阿拉伯数字序号或标识
符，以便下一步相应地标明单位和联系地址；也可以
不这样标明，但一般要求在下一行说明谁是第一作者。
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二、学术论文写作

高分子材料纳米二氧化硅外文文献翻译

纳米二氧化硅对成核、结晶和热塑性能的影响外文文献翻译(含：英文原文及中文译文)文献出处：Laoutid F, Estrada E, Michell R M, et al. The influence of nanosilica on the nucleation, crystallization andtensile properties of PP–PC and PP–PA blends[J]. Polymer, 2013, 54(15):3982-3993.英文原文The influence of nanosilica on the nucleation, crystallization andtensileproperties of PP–PC and PP–PA blendsLaoutid F, Estrada E, Michell R M, et alAbstractImmiscible blends of 80 wt% polypropylene (PP) with 20 wt% polyamide (PA) or polycarbonate (PC) were prepared by melt mixing with or without the addition of 5% nanosilica. The nanosilica produced a strong reduction of the disperse phase droplet size, because of its preferential placement at the interface, as demonstrated by TEM. Polarized Light Optical microscopy (PLOM) showed that adding PA, PC or combinations of PA-SiO2 or PC-SiO2 affected the nucleation density of PP. PA droplets can nucleate PP under isothermal conditions producing a higher nucleation density than the addition of PC or PC-SiO2. PLOM was found to be more sensitive to determine differences in nucleation than non-isothermal DSC. PP developed spherulites, whose growth was unaffected by blending, while its overall isothermal crystallizationkinetics was strongly influenced by nucleation effects caused by blending. Addition of nanosilica resulted in an enhancement of the strain at break of PP-PC blends whereas it was observed to weaken PP-PA blends. Keywords：Nanosilica，Nucleation，PP blends1 OverviewImmiscible polymer blends have attracted attention for decades because of their potential application as a simple route to tailor polymer properties. The tension is in two immiscible polymerization stages. This effect usually produces a transfer phase between the pressures that may allow the size of the dispersed phase to be allowed, leading to improved mixing performance.Block copolymers and graft copolymers, as well as some functional polymers. For example, maleic anhydride grafted polyolefins act as compatibilizers in both chemical affinities. They can reduce the droplet volume at the interface by preventing the two polymers from coalescing. In recent years, various studies have emphasized that nanofillers, such as clay carbon nanotubes and silica, can be used as a substitute for organic solubilizers for incompatible polymer morphology-stabilized blends. In addition, in some cases, nanoparticles in combination with other solubilizers promote nanoparticle interface position.The use of solid particle-stabilized emulsions was first discovered in 1907 by Pickering in the case of oil/emulsion containing colloidalparticles. In the production of so-called "Pickling emulsions", solid nanoparticles can be trapped in the interfacial tension between the two immiscible liquids.Some studies have attempted to infer the results of blending with colloidal emulsion polymer blends. Wellman et al. showed that nanosilica particles can be used to inhibit coalescence in poly(dimethylsiloxane)/polyisobutylene polymers. mix. Elias et al. reported that high-temperature silicon nanoparticles can migrate under certain conditions. The polypropylene/polystyrene and PP/polyvinyl acetate blend interfaces form a mechanical barrier to prevent coalescence and reduce the size of the disperse phase.In contrast to the above copolymers and functionalized polymers, the nanoparticles are stable at the interface due to their dual chemical nature. For example, silica can affect nanoparticle-polymer affinities locally, minimizing the total free energy that develops toward the system.The nanofiller is preferentially placed in equilibrium and the wetting parameters can be predicted and calculated. The difference in the interfacial tension between the polymer and the nanoparticles depends on the situation. The free-diffusion of the nanoparticle, which induces the nanoparticles and the dispersed polymer, occurs during the high shear process and shows that the limitation of the viscosity of the polymer hardly affects the Brownian motion.As a result, nanoparticles will exhibit strong affinity at the local interface due to viscosity and diffusion issues. Block copolymers need to chemically target a particular polymer to the nanoparticle may provide a "more generic" way to stabilize the two-phase system.Incorporation of nanosilica may also affect the performance of other blends. To improve the distribution and dispersion of the second stage, mixing can produce rheological and material mechanical properties. Silica particles can also act as nucleating agents to influence the crystallization behavior. One studies the effect of crystalline silica on crystalline polystyrene filled with polybutylene terephthalate (polybutylene terephthalate) fibers. They found a stable fibril crystallization rate by increasing the content of polybutylene terephthalate and silica. On the other hand, no significant change in the melt crystallization temperature of the PA was found in the PA/ABS/SiO2 nanocomposites.The blending of PP with engineering plastics, such as polyesters, polyamides, and polycarbonates, may be a useful way to improve PP properties. That is, improving thermal stability, increasing stiffness, improving processability, surface finish, and dyeability. The surface-integrated nano-silica heat-generating morphologies require hybrid compatibilization for the 80/20 weight ratio of the thermal and tensile properties of the blended polyamide and polypropylene (increasedperformance). Before this work, some studies [22] that is, PA is the main component). This indicates that the interfacially constrained hydrophobic silica nanoparticles obstruct the dispersed phase; from the polymer and allowing a refinement of morphology, reducing the mixing scale can improve the tensile properties of the mixture.The main objective of the present study was to investigate the effect of nanosilica alone on the morphological, crystalline, and tensile properties of mixtures of nanosilica alone (for mixed phases with polypropylene as a matrix and ester as a filler. In particular, PA/PC or PA/nano The effect of SiO 2 and PC/nanosilica on the nucleation and crystallization effects of PP as the main component.We were able to study the determination of the nucleation kinetics of PP and the growth kinetics of the particles by means of polarization optical microscopy. DSC measures the overall crystallization kinetics.Therefore, a more detailed assessment of the nucleation and spherulite growth of PP was performed, however, the effect of nanosilica added in the second stage was not determined. The result was Akemi and Hoffman. And Huffman's crystal theory is reasonable.2 test phase2.1 Raw materialsThe polymer used in this study was a commercial product: isotactic polypropylene came from a homopolymer of polypropylene. The Frenchformula (B10FB melt flow index 2.16Kg = 15.6g / 10min at 240 °C) nylon 6 from DSM engineering plastics, Netherlands (Agulon Fahrenheit temperature 136 °C, melt flow index 240 °C 2.16kg = 5.75g / 10min ) Polycarbonate used the production waste of automotive headlamps, its melt flow index = 5g / 10min at 240 °C and 2.16kg.The silica powder TS530 is from Cabot, Belgium (about 225 m/g average particle (bone grain) about 200-300 nm in length, later called silica is a hydrophobic silica synthesis of hexamethyldisilane by gas phase synthesis. Reacts with silanols on the surface of the particles.2.2 ProcessingPP_PA and PP-PC blends and nanocomposites were hot melt mixed in a rotating twin screw extruder. Extrusion temperatures range from 180 to 240 °C. The surfaces of PP, PA, and PC were vacuumized at 80°C and the polymer powder was mixed into the silica particles. The formed particles were injected into a standard tensile specimen forming machine at 240C (3 mm thickness of D638 in the American Society for Testing Materials). Prior to injection molding, all the spherulites were in a dehumidified vacuum furnace (at a temperature of 80°C overnight). The molding temperature was 30°C. The mold was cooled by water circulation. The mixture of this combination is shown in the table.2.3 Feature Description2.31 Temperature Performance TestA PerkineElmer DSC diamond volume thermal analysis of nanocomposites. The weight of the sample is approximately 5 mg and the scanning speed is 20 °C/min during cooling and heating. The heating history was eliminated, keeping the sample at high temperature (20°C above the melting point) for three minutes. Study the sample's ultra-high purity nitrogen and calibrate the instrument with indium and tin standards.For high temperature crystallization experiments, the sample cooling rate is 60°C/min from the melt directly to the crystal reaching the temperature. The sample is still three times longer than the half-crystallization time of Tc. The procedure was deduced by Lorenzo et al. [24] afterwards.2.3.2 Structural CharacterizationScanning electron microscopy (SEM) was performed at 10 kV using a JEOL JSM 6100 device. Samples were prepared by gold plating after fracture at low temperature. Transmission electron microscopy (TEM) micrographs with a Philips cm100 device using 100 kV accelerating voltage. Ultra-low cut resection of the sample was prepared for cutting (Leica Orma).Wide-Angle X-Ray Diffraction Analysis The single-line, Fourier-type, line-type, refinement analysis data were collected using a BRUKER D8 diffractometer with copper Kα radiation (λ = 1.5405A).Scatter angles range from 10o to 25°. With a rotary step sweep 0.01° 2θ and the step time is 0.07s. Measurements are performed on the injection molded disc.This superstructure morphology and observation of spherulite growth was observed using a Leica DM2500P polarized light optical microscope (PLOM) equipped with a Linkam, TP91 thermal stage sample melted in order to eliminate thermal history after; temperature reduction of TC allowed isothermal crystallization to occur from the melt. The form is recorded with a Leica DFC280 digital camera. A sensitive red plate can also be used to enhance contrast and determine the birefringence of the symbol.2.3.3 Mechanical AnalysisTensile tests were carried out to measure the stretch rate at 10 mm/min through a Lloyd LR 10 K stretch bench press. All specimens were subjected to mechanical tests for 20 ± 2 °C and 50 ± 3% relative humidity for at least 48 hours before use. Measurements are averaged over six times.3 results3.1 Characterization by Electron MicroscopyIt is expected that PP will not be mixed with PC, PA because of their different chemical properties (polar PP and polar PC, PA) blends with 80 wt% of PP, and the droplets and matrix of PA and PC are expectedmorphologies [ 1-4] The mixture actually observed through the SEM (see Figures 1 a and b).In fact, because the two components have different polar mixtures that result in the formation of an unstable morphology, it tends to macroscopic phase separation, which allows the system to reduce its total free energy. During shearing during melting, PA or PP is slightly mixed, deformed and elongated to produce unstable slender structures that decompose into smaller spherical nodules and coalesce to form larger droplets (droplets are neat in total The size of the blend is 1 ~ 4mm.) Scanning electron microscopy pictures and PP-PC hybrid PP-PA neat and clean display left through the particle removal at cryogenic temperatures showing typical lack of interfacial adhesion of the immiscible polymer blend.The addition of 5% by weight of hydrophobic silica to the LED is a powerful blend of reduced size of the disperse phase, as can be observed in Figures 1c and D. It is worth noting that most of the dispersed phase droplets are within the submicron range of internal size. The addition of nano-SiO 2 to PA or PC produces finer dispersion in the PP matrix.From the positional morphology results, we can see this dramatic change and the preferential accumulation at the interface of silica nanoparticles, which can be clearly seen in FIG. 2 . PP, PA part of the silicon is also dispersed in the PP matrix. It can be speculated that thisformation of interphase nanoparticles accumulates around the barrier of the secondary phase of the LED, thus mainly forming smaller particles [13, 14, 19, 22]. According to fenouillot et al. [19] Nanoparticles are mixed in a polymer like an emulsifier; in the end they will stably mix. In addition, the preferential location in the interval is due to two dynamic and thermodynamic factors. Nanoparticles are transferred to the preferential phase, and then they will accumulate in the interphase and the final migration process will be completed. Another option is that there isn't a single phase of optimization and the nanoparticles will be set permanently in phase. In the current situation, according to Figure 2, the page is a preferential phase and is expected to have polar properties in it.3.2 Wide-angle x-ray diffractionThe polymer and silica incorporate a small amount of nanoparticles to modify some of the macroscopic properties of the material and the triggered crystal structure of PP. The WAXD experiment was performed to evaluate the effect of the incorporation of silica on the crystalline structure of the mixed PP.Isotactic polypropylene (PP) has three crystalline forms: monoclinic, hexagonal, and orthorhombic [25], and the nature of the mechanical polymer depends on the presence of these crystalline forms. The metastable B form is attractive because of its unusual performance characteristics, including improved impact strength and elongation atbreak.The figure shows a common form of injection molding of the original PP crystal, reflecting the appearance at 2θ = 14.0, 16.6, 18.3, 21.0 and 21.7 corresponding to (110), (040), (130), (111) and (131) The face is an α-ipp.20% of the PA incorporation into PP affects the recrystallization of the crystal structure appearing at 2θ = 15.9 °. The corresponding (300) surface of the β-iPP crystal appears a certain number of β-phases that can be triggered by the nucleation activity of the PA phase in PP (see evidence The following nucleation) is the first in the crystalline blend of PA6 due to its higher crystallization temperature. In fact, Garbarczyk et al. [26] The proposed surface solidification caused by local shear melts the surface of PA6 and PP and forms during the injection process, promoting the formation of β_iPP. According to quantitative parameters, KX (Equation (1)), which is commonly used to evaluate the amount of B-crystallites in PP including one and B, the crystal structure of β-PP has 20% PP_PA (110), H(040) and Blends of H (130) heights (110), (040) and (130). The height at H (300) (300) for type A peaks.However, the B characteristic of 5 wt% silica nanoparticles incorporated into the same hybrid LED eliminates reflection and reflection a-ipp retention characteristics. As will be seen below, the combination of PA and nanosilica induces the most effective nucleatingeffect of PP, and according to towaxd, this crystal formation corresponds to one PP structure completely.The strong reductive fracture strain observations when incorporated into polypropylene and silica nanoparticles (see below) cannot be correlated to the PP crystal structure. In fact, the two original PP and PP_PA_SiO2 hybrids contain α_PP but the original PP has a very high form of failure when the strain value.On the other hand, PP-PC and PP-PC-Sio 2 blends, through their WAXD model, can be proven to contain only one -PP form, which is a ductile material.3.3 Polarized Optical Microscopy (PLOM)To further investigate the effect of the addition of two PAs, the crystallization behavior of PC and silica nanoparticles on PP, the X-ray diffraction analysis of its crystalline structure of PP supplements the study of quantitative blends by using isothermal kinetic conditions under a polarizing microscope. The effect of the composition on the nucleation activity of PP spherulite growth._Polypropylene nucleation activityThe nucleation activity of a polymer sample depends on the heterogeneity in the number and nature of the samples. The second stage is usually a factor in the increase in nucleation density.Figure 4 shows two isothermal crystallization temperatures for thePP nucleation kinetics data. This assumes that each PP spherulite nucleates in a central heterogeneity. Therefore, the number of nascent spherulites is equal to the number of active isomerous nuclear pages, only the nucleus, PP-generated spherulites can be counted, and PP spherulites are easily detected. To, while the PA or PC phases are easily identifiable because they are secondary phases that are dispersed into droplets.At higher temperatures (Fig. 4a), only the PP blend inside is crystallized, although the crystals are still neat PP amorphous at the observed time. This fact indicates that the second stage of the increase has been able to produce PP 144 °C. It is impossible to repeat the porous experiment in the time of some non-homogeneous nucleation events and neat PP exploration.The mixed PP-PC and PP-PC-SiO 2 exhibited relatively low core densities at 144 °C, (3 105 and 3 106 nuc/cm 3) suggesting that either PC nanosilica can also be considered as good shape Nuclear agent is used here for PP.On the other hand, PA, himself, has produced a sporadic increase in the number of nucleating events in PP compared to pure PP, especially in the longer crystallization time (>1000 seconds). In the case of the PP-PA _Sio 2 blend, the heterogeneous nucleation of PP is by far the largest of all sample inspections. All the two stages of the nucleating agent combined with PA and silica are best employed in this work.In order to observe the nucleation of pure PP, a lower crystallization temperature was used. In this case, observations at higher temperatures found a trend that was roughly similar. The neat PP and PP-PC blends have small nucleation densities in the PP-PC-SiO 2 nanocomposite and the increase also adds further PP-PA blends. The very large number of PP isoforms was rapidly activated at 135°C in the PP-PA nanoparticle nanometer SiO 2 composites to make any quantification of their numbers impossible, so this mixed data does not exist from Figure 4b.The nucleation activity of the PC phase of PP is small. The nucleation of any PC in PP can be attributed to impurities that affect the more complex nature of the PA from the PC phase. It is able to crystallize at higher temperatures than PP, fractional crystallization may occur and the T temperature is shifted to much lower values (see References [29-39]. However, as DSC experiments show that in the current case The phase of the PA is capable of crystallizing (fashion before fractionation) the PP matrix, and the nucleation of PP may have epitaxy origin.The material shown in the figure represents a PLOAM micrograph. Pure PP has typical α-phase negative spherulites (Fig. 5A) in the case of PP-PA blends (Fig. 5B), and the PA phase is dispersed with droplets of size greater than one micron (see SEM micrograph, Fig. 1) . We could not observe the spherulites of the B-phase type in PP-PA blends. Even according to WAXD, 20% of them can be formed in injection moldedspecimens. It must be borne in mind that the samples taken using the PLOAM test were cut off from the injection molded specimens but their thermal history (direction) was removed by melting prior to melting for isothermal crystallization nucleation experiments.The PA droplets are markedly enhanced by the nucleation of polypropylene and the number of spherulites is greatly increased (see Figures 4 and 5). Simultaneously with the PP-PA blend of silica nanoparticles, the sharp increase in nucleation density and Fig. 5C indicate that the size of the spherulites is very small and difficult to identify.The PP-PC blends showed signs of sample formation during the PC phase, which was judged by large, irregularly shaped graphs. Significant effects: (a) No coalesced PC phase, now occurring finely dispersed small droplets and (B) increased nucleation density. As shown in the figure above, nano-SiO 2 tends to accumulate at the interface between the two components and prevent coalescence while promoting small disperse phase sizes.From the nucleation point of view, it is interesting to note that it is combined with nanosilica and as a better nucleating agent for PP. Combining PCs with nanosilica does not produce the same increase in nucleation density.Independent experiments (not shown here) PP _ SiO 2 samplesindicate that the number of active cores at 135 °C is almost the same as that of PP-PC-SiO2 intermixing. Therefore, silica cannot be regarded as a PP nucleating agent. Therefore, the most likely explanation for the results obtained is that PA is the most important reason for all the materials used between polypropylene nucleating agents. The increase in nucleation activity to a large extent may be due to the fact that these nanoparticles reduce the size of the PA droplets and improve its dispersion in the PP matrix, improving the PP and PA in the interfacial blend system. Between the regions. DSC results show that nano-SiO 2 is added here without a nuclear PA phase.4 Conclusion5% weight of polypropylene/hydrophobic nanosilica blended polyamide and polypropylene/polycarbonate (80E20 wt/wt) blends form a powerful LED to reduce the size of dispersed droplets. This small fraction of reduced droplet size is due to the preferential migration of silica nanoparticles between the phases PP and PA and PC, resulting in an anti-aggregation and blocking the formation of droplets of the dispersed phase.The use of optical microscopy shows that the addition of PA, the influence of PC's PA-Sio 2 or PC-Sio 2 combination on nucleation, the nucleation density of PP polypropylene under isothermal conditions is in the following approximate order: PP <PP-PC <PP -PC-SiO 2<<PP-PA<<< PP-PA-SiO 2. PA Drip Nucleation PP Production of nucleation densities at isothermal temperatures is higher than with PC or PC Sio 2D. When nanosilica is also added to the PP-PA blend, the dispersion-enhanced mixing of the enhanced nanocomposites yields an intrinsic factor PP-PA-Sio2 blend that represents a PA that is identified as having a high nucleation rate, due to nanoseconds Silicon oxide did not produce any significant nucleation PP. PLOAM was found to be a more sensitive tool than traditional cooling DSC scans to determine differences in nucleation behavior. The isothermal DSC crystallization kinetics measurements also revealed how the differences in nucleation kinetics were compared to the growth kinetic measurements.Blends (and nanocomposites of immiscible blends) and matrix PP spherulite assemblies can grow and their growth kinetics are independent. The presence of a secondary phase of density causes differences in the (PA or PC) and nanosilica nuclei. On the other hand, the overall isothermal crystallization kinetics, including nucleation and growth, strongly influence the nucleation kinetics by PLOAM. Both the spherulite growth kinetics and the overall crystallization kinetics were successfully modeled by Laurie and Huffman theory.Although various similarities in the morphological structure of these two filled and unfilled blends were observed, their mechanical properties are different, and the reason for this effect is currently being investigated.The addition of 5% by weight of hydrophobic nano-SiO 2 resulted in breaking the strain-enhancement of the PP-PC blend and further weakening the PP-PA blend.中文译文纳米二氧化硅对PP-PC和PP-PA共混物的成核，结晶和热塑性能的影响Laoutid F, Estrada E, Michell R M, et al摘要80(wt%)聚丙烯与20(wt %)聚酰胺和聚碳酸酯有或没有添加5%纳米二氧化硅通过熔融混合制备不混溶的共聚物。

Language structure of pattern Sturmian words

Discrete Mathematics 306(2006)1651–1668/locate/discLanguage structure of pattern Sturmian wordsTeturo Kamae a ,Hui Rao b ,Bo Tan c ,Yu-Mei Xue ba Matsuyama University,790-8578,Japanb Department of Mathematics,Tsinghua University,Beijing 100084,PR Chinac Department of Mathematics,Huazhong University of Science and Technology,Wuhan 430074,PR China Received 28November 2005;received in revised form 14March 2006;accepted 28March 2006Available online 19June 2006AbstractPattern Sturmian words introduced by Kamae and Zamboni [Sequence entropy and the maximal pattern complexity of inﬁnite words,Ergodic Theory Dynamical Systems 22(2002)1191–1199;Maximal pattern complexity for discrete systems,Ergodic Theory Dynamical Systems 22(2002)1201–1214]are an analogy of Sturmian words for the maximal pattern complexity instead of the block complexity.So far,two kinds of recurrent pattern Sturmian words are known,namely,rotation words and Toeplitz words.But neither a structural characterization nor a reasonable classiﬁcation of the recurrent pattern Sturmian words is known.In this paper,we introduce a new notion,pattern Sturmian sets,which are used to study the language structure of pattern Sturmian words.We prove that there are exactly two primitive structures for pattern Sturmian words.Consequently,we suggest a classiﬁcation of pattern Sturmian words according to structures of pattern Sturmian sets and prove that there are at most three classes in this classiﬁcation.Rotation words and Toeplitz words fall into two different classes,but no examples of words from the third class are known.©2006Elsevier B.V .All rights reserved.Keywords:Uniform complexity;Pattern Sturmian word;Language structure1.Introduction1.1.Pattern Sturmian wordsLet A denote a nonempty ﬁnite set which is called an alphabet .Let ∈A N be an inﬁnite word over A ,where N ={0,1,2,...}is the index set .Let k be a positive integer.By a k -window ,we mean a subset of N with cardinality k .For a word ∈A N and a k -window ={ 0< 1<···< k −1},we denote[n + ]:= (n + 0) (n + 1)··· (n + k −1)∈A ,F ( ):={ [n + ];n ∈N },p ( ):=#F ( ),where [n + ]is considered as a word on the index set ,and #E denotes the cardinality of a ﬁnite set E .An element in F ( )is called a -factor of .The maximal pattern complexity p ∗for a word is introduced by Kamae and E-mail addresses:kamae@apost.plala.or.jp (T.Kamae),hrao@ (H.Rao),bo_tan@ (B.Tan),yxue@ (Y-M.Xue).0012-365X/$-see front matter ©2006Elsevier B.V .All rights reserved.doi:10.1016/j.disc.2006.03.0431652T.Kamae et al./Discrete Mathematics306(2006)1651–1668Zamboni[10]asp ( )(k=1,2,3,...),p∗ (k):=supwhere the supremum is taken over all k-windows .The block complexity p is deﬁned asp (k)=p ({0,1,...,k−1}).Morse and Hedlund[14]characterized the eventually periodicity in term of block complexity by showing that a word is eventually periodic if and only if p (k)<k+1for some k∈Z+:={1,2,...}.A word with block complexity p (k)=k+1(k∈Z+),which is of the minimal complexity among the nonperiodic words,is known as a Sturmian word.Excellent descriptions of Sturmian words can be found in Chapter2of[13]by J.Berstel and P.Séébold,and in Chapter6of[5]by P.Arnoux.In a similar way,Kamae and Zamboni[10]characterized the eventually periodicity in term of maximal pattern complexity.They proved that a word is eventually periodic if and only if p∗ (k)<2k for some k∈Z+.Accordingly, a word with p∗ (k)=2k(k∈Z+)is called a pattern Sturmian word.It is shown that Sturmian words are pattern Sturmian.Indeed,the class of pattern Sturmian words is larger than that of Sturmian words.Till now,three classes of pattern Sturmian words are known:rotation words,Toeplitz words and a class of{0,1}-words with rare1,where theﬁrst two of them are recurrent,while the last ones are not(see[10,11]). We do not know whether there are pattern Sturmian words other than of these kinds or not.We are also interested in what are the common points of the three known pattern Sturmian words,and what are the differences between them.In this paper,we analyze the language structure of recurrent pattern Sturmian words,and try to answer these questions.1.2.Uniform setLet A be an alphabet and be a countable inﬁnite set.An element w∈A (which is a mapping from to A)is called a word on the index set over A,or a -word over A.For a nonemptyﬁnite set S⊂ ,deﬁne S(w)to be the S-word which is the restriction of w to S.For ⊂A ,put S( ):={ S(w);w∈ }.A subset ⊂A is called a uniform set if# S( )depends only on the size of S.Thus,we introduce the uniform complexity function p :Z+→Z+by p (k)=# S( )with#S=k.Special concern is paid to two classes of uniform sets,namely,Sturmian sets with p (k)=k+1(k∈Z+)and pattern Sturmian sets with p (k)=2k(k∈Z+).Example1.1.Take =N.A word ∈{0,1}N is called an increasing word(a decreasing word)if (i) (j) ( (i) (j),resp.)whenever i<j.A word is monotone if it is increasing or decreasing.A word ∈{0,1}N is called a Dirac word if there exists i0∈N such that (i)=0for any i=i0.Deﬁne0:={ ∈{0,1} ; is increasing},0:={ ∈{0,1} ; is Dirac},1:={ ∈{0,1} ; is monotone},1:={ ∈{0,1} ; is either decreasing or Dirac},2:={ ∈{0,1} ; is either increasing or Dirac}.Then,it is easily seen that 0and 0are Sturmian sets,while 1, 1and 2are pattern Sturmian sets.These sets will play an important role in our study and these notations will be used throughout the paper.We will show that a uniform set isﬁnite if and only if p (k) k holds for some k(Proposition2.3).Hence,a Sturmian set is an inﬁnite uniform set with the minimum uniform complexity.As we will see,the pattern Sturmian sets are closely related to the pattern Sturmian words.T.Kamae et al./Discrete Mathematics306(2006)1651–16681653Fig.1. 0and 0.Fig.2. 1and 1.Fig.3. 2.1.3.Classiﬁcation of recurrent pattern Sturmian wordsWe study the language structure of the uniform sets on the index set N.We introduce in Section3the notion of isomorphism between uniform sets U and V on N,so that U and V are isomorphic to each other if and only if the trees representing the extension schemes of the languages of them along the indices0,1,2,...are isomorphic.Then,the structure of a uniform set on the index set N is deﬁned to be the isomorphic class of this isomorphism containing ,which is denoted by[ ].It holds that in Example1.1, 0and 0are isomorphic to each other and 1and 1are isomorphic to each other, while 1and 2are not isomorphic(see Figs.1–3).Let N={n0<n1<n2<···}⊂N and N:{0,1}N→{0,1}N be such that N( )(k)= (n k)(k∈N).The induced set (N)of a set on N is deﬁned to be the set N( ).It is a uniform set on N if is so.A uniform set is called primitive if all induced sets of are isomorphic to itself.The structure[ ]for a primitive uniform set is called primitive.That is,[ ]is primitive if there exists a primitive element in[ ].We prove that[ 0]is the unique primitive structure among the Sturmian sets,while there are exactly two different primitive structures among the pattern Sturmian sets,namely,[ 1]and[ 2].The uniform sets are interesting subject to be studied in general.For example,how to characterize the uni-form complexity functions is an interesting problem.Here,we only discussﬁnite uniform sets,Sturmian sets and1654T.Kamae et al./Discrete Mathematics306(2006)1651–1668pattern Sturmian sets in Sections2and3.The results there except Theorem3.5are irrelevant to the arguments after Section3.1.4.Ultimate structureGiven a recurrent pattern Sturmian word ∈{0,1}N.We prove in Theorem4.1that there exists an inﬁnite subset N of N,which is called an optimal window,such that for any nonemptyﬁnite set ⊂N,we have p ( )=2# .Then, we have a pattern Sturmian set ( )(N),where ( )denotes the orbit closure of with respect to the shift on{0,1}N. We denote by US( )the set of structures[ ( )(N)]for all optimal windows N of such that ( )(N)is primitive. We prove that US( )={[ 1]}for all rotation words ,while US( )={[ 2]}for all Toeplitz words (Theorems4.3 and4.8).Thus,we can classify the recurrent pattern Sturmian words in terms of the language structure. Specially,for Toeplitz words,we give concrete constructions of optimal windows,which give an alternative proof of the fact that the simple Toeplitz words are pattern Sturmian,which is presented with a wrong proof in[11].Also remark that a proof of this fact in a more general setting can be found in[7].1.5.More references on the complexity in generalTo survey the block complexity in general,see Ferenczi[4].The block complexity of general Toeplitz words are discussed by Cassaigne and Karhumäki[3]and Koskas[12].Other kinds of complexity are deﬁned and discussed by Allouche et al.[1],Avgustinovich et al.[2],Frid[6],Nakashima et al.[15],Restivo and Salemi[16].The notion of pattern Sturmian words is extended to the words over letters in[8],and to the two-dimensional words in[9].anization of the paperThis paper is organized as follows.Sections2and3are devoted to the study of uniform sets.In Section2,the notion of uniform sets is introduced and some basic properties are investigated.We are specially interested in the pattern Sturmian sets which have the uniform complexity2k.In Section3,we study the isomorphism between uniform sets. The isomorphism classes are called structures.We prove that there exist exactly two primitive structures among the pattern Sturmian sets.Section4is devoted to the study of language structure of pattern Sturmian words.In Section 4.1,we prove that all recurrent pattern Sturmian words admit optimal windows,which deﬁne the ultimate structure of them.In Section4.2,we study the ultimate structure of the rotation words,while in Section4.3,we study the ultimate structure of the Toeplitz words.2.Uniform setsLet A be an alphabet and be an index set.Let F k(k∈Z+)be the collection of subsets of consisting of k elements,that is,F k={S⊂ ;#S=k}.Set F=∪k 1F k.For S⊂ ,a S-word over A is called a constant word if there exists a∈A such that ( )=a for any ∈S.Let S and S be two disjoint subsets of ,w and w be an S-word and an S -word,respectively,the concatenation of w and w is deﬁned to be the S∪S -word ww with the property ww ( )=w( )if ∈S and ww ( )=w ( )if ∈S .Given w∈ S( ).If w ∈ S ( )satisﬁes that ww ∈ S∪S ( ),then we say that w is an S -extension of w in . For ∈ \S,w∈ S( )is called -special if there are at least two different{ }-extensions of w in .The complexity of is the function p :F→Z+deﬁned by p (S)=# S .Deﬁnition2.1.A nonempty subset ⊂A is called a uniform set if the complexity p (S)depends only on#S.If is a uniform set,we have a function p :Z+→Z+such that p (k)=p (S)for any S∈F k.The function p is called the uniform complexity function.From now on,we always take A={0,1}.We consider theﬁnite uniform setsﬁrst.T.Kamae et al./Discrete Mathematics306(2006)1651–16681655Proposition2.2.Let ∈{0,1} be aﬁnite uniform set,then either(i)p (k)≡1and ={w}for some w∈{0,1} or(ii)p (k)≡2and ={w,w}for some w∈{0,1} ,where we put0=1,1=0and w( )=w( )for any ∈ .Proof.Assume that ={w1,w2,...,w n}is a uniform set.For ∈ ,deﬁne a vector v( )=(w1( ),w2( ),...,w n( ))∈{0,1}n.Since there are onlyﬁnite number of vectors in{0,1}n,there exists a vector v,such that v( )=v for inﬁnitely many of .Denote ={ ;v( )=v}.Then for any S⊂ , S( )consists only of constant words,so that# S( ) 2.Since#S as above can be any positive number and is uniform,we have p (k) 2(k=1,2,...).This implies that either p (k)≡1or p (k)≡2since p (k)is an increasing function of k and p (1)=1implies p (k)=1(k=1,2,...).On the other hand,if p (k)≡1,then is a singleton;and if p (k)≡2,then ={w,w}.Proposition2.3.Let be a uniform set.If there exists k such that p (k) k,then is aﬁnite set.Proof.If p (1)=1,then is a singleton.If p (1)=2and p (k) k,then there exists a k <k such that p (k +1)=p (k ).Take S⊂ with#S=k .Then for any ∈ \S and w∈ ,since p (k +1)=p (k ),w( )is determined by the S-word S(w).Hence w is determined by S(w),and is aﬁnite set.Deﬁnition2.4.A uniform set ⊂{0,1} is called a Sturmian set if the uniform complexity satisﬁes p (k)=k+1 for any k∈Z+; is called a pattern Sturmian set if the uniform complexity satisﬁes p (k)=2k for any k∈Z+. Hence,Sturmian sets have the minimal uniform complexity among all the inﬁnite uniform set by Proposition2.3. Examples of Sturmian sets and pattern Sturmian sets are given in Example1.1.We have the following characterizations. Theorem2.5.If is a uniform set.Then, is a Sturmian set if and only if p (2)=3.Proof.Obviously,the condition p (2)=3is necessary.To show the sufﬁciency,suppose that is uniform and p (2)=3.Then by Propositions2.2and2.3, is an inﬁnite set and p (k) k+1for any k∈Z+.So we only need to show that p (k) k+1.Otherwise,suppose that p (k) k+2for some k 3.Then there exists a k <k such that p (k +1) p (k )+2. Take S⊂ with#S=k and ∈ \S.Since A={0,1}and each S-word has at most two{ }-extensions,there are two S-words w1and w2which are -special.Since w1and w2are distinct,there exists a ∈S such that w1( )=w2( ). So { , }( )={00,01,10,11}and p (2)=4,a contradiction.A uniform set is said to fulﬁll(k)-Condition if its uniform complexity satisﬁesp (m)=2m for m=1,2,...,k;but p (k+1)=2k+1.Thus,by Theorem2.5, is a Sturmian set if and only if it fulﬁlls(1)-Condition.The following lemma will be used for the characterization of pattern Sturmian sets.Lemma2.6.Let be a uniform set.(1)There exists an inﬁnite subset ⊂ such that ( )contains at least one constant word.(2)If fulﬁlls(k)-Condition for some k 2,then for any S⊂ with S=k,there exist 1∈ S( )and an inﬁnitesubset ⊂ \S such that 1is{ }-special for any ∈ and{ (w);w∈ and S(w)=w1}consists of two constant words.Proof.(1)Take an arbitrary word ∈ .Since is an inﬁnite set,there exists an inﬁnite subset such that ( ) is a constant word.Thus, ( )contains at least one constant word.1656T.Kamae et al./Discrete Mathematics 306(2006)1651–1668(2)Assume that fulﬁlls (k)-Condition for some k 2.Take S ⊂ with #S =k and write S ( )={w 1,w 2,...,w 2k }.Since p (k +1)=2k +1,for any ∈ \S ,just one element in {w 1,w 2,...,w 2k }is -special.Therefore,without loss of generality,we may assume that there exists an inﬁnite set ⊂ \S such that w 1is the only element in S ( )which is -special for any ∈ and{ (w);w ∈ and S (w)=w 1}consists only of constant words.We conclude the proof by claiming that both constant words with 0and 1are included in the above set.Otherwise taking ∈S and ∈ ,one can ﬁnd only three different { , }-words,which contradicts the fact that p (2)=4. Theorem 2.7.If is a uniform set .Then is a pattern Sturmian set if and only if p (2)=4and p (3)=6.Proof.We only need to show that if is uniform and p (2)=4,p (3)=6,then p (k)=2k for any k .•p (k) 2k for any k 1:otherwise,there exists a k 3such that p (k +1) p (k)+3.Take S ⊂ with #S =k and ∈ \S .There are three S -words w 1,w 2and w 3which are -special.Since w 1,w 2and w 3are distinct,there exists a 1, 2∈S such that { 1, 2}(w 1), { 1, 2}(w 2)and { 1, 2}(w 3)are different from each other.Also all of them are -special.Since p (2)=4,there is another { 1, 2}-word besides { 1, 2}(w 1), { 1, 2}(w 2)and { 1, 2}(w 3)which has at least one { }-extension.Then { 1, 2, }( ) 7,which contradicts the assumption p (3)=6.•p (k) 2k for any k 1:otherwise,there exists a k 3such that p (k +1) p (k)+1.If p (k +1)=p (k),then as in the proof of Proposition 2.3,we can show that is ﬁnite which is a contradiction.It remains only one possibility: fulﬁlls (k)-Condition for some k 3.In this case,ﬁx S ⊂ with #S =k .Then # S ( )=2k , S ( )={w 1,w 2,...,w 2k }.By Lemma 2.6(2),there exists an inﬁnite subset ⊂ \S and w 1∈ S ( )such that w 1is -special for any ∈ and { (w);w ∈ and S (w)=w 1}consists only of the two constant words.Construct a set as follows:={ (w);w ∈ and S (w)=w 1}.We claim that is a uniform set.To see this,for a ﬁxed ﬁnite subset S ⊂ ,consider the S ∪S -words of .Since any S -word but w 1has a unique S -extension,and w 1has just p (S )different S -extensions,we havep (S )=p (S ∪S )−(2k −1)=p (k +#S )−(2k −1)which implies is a uniform set such thatp (m)=p (k +m)−(2k −1)for any m 1.Obviously,p (1)=2.We claim that p (2)=4.Otherwise p (2)=2or 3.If p (2)=2,then by Propositions 2.2and 2.3, ={ , }for some ∈{0,1} .Take S ⊂ with #S =3.Consider the set S ( )which is the union of S ( )and the two constant words.Then,we havep (S ) 2+2=4,contradicting to the fact that p (3)=6.If p (2)=3,then is a Sturmian set.Then by Lemma 2.6(1),there exists a three-elements subset S ⊂ such that S ( )consists of four elements and among them at least one is a constant word.Consider the set S ( )which is the union of S ( )and the two constant words.Then,p (S ) 4+2−1=5,contradicting to the fact that p (3)=6.T.Kamae et al./Discrete Mathematics306(2006)1651–16681657Moreover,since is deﬁned on ⊂ and ⊂ ( ),we havep (m) p (m)for any m 1.Therefore, fulﬁlls(k )-Condition for some2 k k.Due to Lemma2.6(2)applied to ,there exists an inﬁnite set ⊂ such that := ( )contains the two constant words.Replacing and by these and ,we may assume that the above contains the two constant words.Since for any S ⊂ , S ( )is the union of S ( )and two constant words,we have S ( )= S ( )and p ≡p .On the other hand,ﬁx ∈S and S ⊂ with#S =m.Without loss of generality,assume that w1( )=0.Since p (2)=4,for any ∈S , { , }={00,01,10,11}.Since S ( )contains both the constant words, { }∪S ( )={0w;w∈ S ( )}∪{10m,11m},where,for example,10m denotes the{ }∪S -word w with w( )=1and w(s)=0for s∈S .Since the union is disjoint, p (m+1)=p (m)+2for any m 1.This is a contradiction against the facts p ≡p ,p (k)=2k and p (k+1)=2k+1,which completes the proof of p (k) 2k.3.Isomorphism between uniform setsIn this section,we consider only the uniform sets on the index set :=N equipped with the natural total ordering. Recall that the alphabet A is always{0,1}.The product topology deﬁned on{0,1}N is consistent with the following metric:for x=x(0)x(1)x(2)...,y= y(0)y(1)y(2)...∈{0,1}N,d(x,y)=2−inf{k∈N;x(k)=y(k)}.Thus two points are closer to each other if they share a longer preﬁx.The cylinder[ ],where = 1 2··· n∈{0,1}n, is the set of words of the form[ ]={x∈{0,1}N;x(0)= 1,x(1)= 2,...,x(n−1)= n}.The order of a cylinder[ ]is deﬁned to be the length n of ,denoted by| |.Note that for the empty word∅, []:=[∅]={0,1}N.Deﬁnition3.1.Two uniform sets , ⊂{0,1}N are said to be isomorphic to each other,written ≈ ,if there is an isometry between their closures and ,that is,there is a bijection : → such that for any x,y∈ , d( (x), (y))=d(x,y).An equivalence class of uniform sets with respect to this isomorphism is called a structure.The structure containing is denoted by[ ].Note that and its closure always have the same language,that is,the set ofﬁnite words appearing in and coincide.Also,note that two uniform sets which are isomorphic to each other have the same uniform complexity. For a uniform set ⊂{0,1}N,we deﬁne the preﬁx tree G( )as follows:G( )=(V,E)is a directed graph. The set V of vertices is the set of the cylinders which meet ,and the set E of(directed)edges is the set of the ordered pairs([u],[v])of cylinders in V such that v is an immediate extension of u,that is,|v|=|u|+1and u1=v1, u2=v2,...,u|u|=v|u|.Recall that two directed graphs G=(V,E)and G =(V ,E )are isomorphic,written G G ,if there is a bijection :V→V between their vertices,such that there is an edge in E from u to v if and only if there is an edge in E from (u)to (v).Theorem3.2.Let and be two uniform sets.Then ≈ if and only if G( ) G( ).1658T.Kamae et al./Discrete Mathematics306(2006)1651–1668Proof.If ≈ ,then there is an isometry : → .Thus,x,y∈ are in an identical cylinder of order n if and only if (x)and (y)are also in an identical cylinder of order n in .Hence, induces a bijection between the cylinders intersecting with and the cylinders intersecting with keeping the orders.Thus, is a bijection between the vertices of G( )and G( )which preserves the edges,and is an isomorphism between G( )and G( ). Conversely,assume G( ) G( ).Noticing that there is a natural correspondence between the words in and theinﬁnite paths from the root in G( ),the isomorphism between the preﬁx trees induces a map : → ,which is an isometry.Let N={n0<n1<n2<···}be an inﬁnite subset of N.Let be a uniform set on N.Recall the notion of induced set (N)of on N in Section1.3.Deﬁnition3.3.A uniform set ⊂{0,1}N or a structure[ ]is said to be primitive if for any inﬁnite subset N⊂N, the induced set (N)is isomorphic to the original set .All the uniform sets in Example1.1are easily seen to be primitive.Their preﬁx trees are depicted in Figs.1–3.Theorem3.4.For any Sturmian set ,there exists an inﬁnite subset N⊂N such that (N)≈ 0.In particular,if is primitive,then ≈ 0.Hence,[ 0]is the unique primitive structure among the Sturmian sets.Proof.Let ⊂{0,1}N be a Sturmian set.Put n0=0.Just as in the proof of Lemma2.6,we can take an inﬁnite set N1⊂N\{n0}such that one{n0}-word, say a(∈{0,1}),is -special for ∈N1,while the other{n0}-word a has only one{ }-extension for any ∈N1. Put ={ N1( ); ∈ with (n0)=a}.Then, is again a Sturmian set since for any set S⊂N1with#S=k,p (S)=p (S∪{n0})−1=k+2−1=k+1.Put n1=min N1,and we continue the above process:ﬁnd N2⊂N1\{n1}such that in one{n1}-word has a unique N2-extension while the N2-extensions of the other{n1}-word form a Sturmian set.Put n2=min N2,and so on.At last,setting N={n0,n1,n2,...},by the construction of N we have (N)≈ 0(see Fig.1).Moreover,if is primitive,then ≈ (N)≈ 0.The next theorem characterizes the primitive pattern Sturmian sets.Theorem3.5.Let be a pattern Sturmian set.Then either (N)≈ 1for some N⊂N or (N)≈ 2for some N⊂N.In particular,if is primitive,then either ≈ 1or ≈ 2.Hence,[ 1]and[ 2]are the only primitive structures among the pattern Sturmian sets.Proof.Let ⊂{0,1}N be a pattern Sturmian set.For any , ∈N with < , { , }( )={00,01,10,11}because p (2)=4.For any > ,since p (3)=6,there are two{ , }-words which are -special.If one of the special words comes from the set{00,01}and the other comes from{10,11},we call a{ , }-balanced place.If all butﬁnite number of places are{ , }-balanced places,we say that is{ , }-balanced.If is{ , }-balanced for any , ∈N with < ,we say that is balanced.We consider two cases according to the balance property.Case1: is balanced.Take n0=0,n1=1.Since is{n0,n1}-balanced,we can take an inﬁnite subset N1⊂{n1+1,n1+2,...}such that one{n0,n1}-word in{00,01}is -special for any ∈N1,and one{n0,n1}-word in{10,11}is also -special for any ∈N1.Any of the other two words in{00,01,10,11}has a unique N1-extension.Take n2=min N1.For any{n0,n1}-word w which is{n2}-special,w0,w1∈ {n0,n1,n2}( ).Since is{n0,n2}-balanced,for all butﬁnite number of ’s with >n2,one word in{w0,w1}is not -special,we can take an inﬁnite subset N2⊂N1\{n2}such that,for all{n0,n1}-words w which are{n2}-special,one word in{w0,w1}has a unique N2-extension.T.Kamae et al./Discrete Mathematics 306(2006)1651–16681659Take n 3=min N 2.Since 4words in {n 0,n 1,n 2}( )have a unique {n 3}-extension and p (4)=8,the other 2words in {n 0,n 1,n 2}( )are n 3-special.One of these 2words starts by 0and the other starts by 1.We continue the above process.Finally,we get N ={n 0,n 1,n 2,n 3,...}such that (N )≈ 1(see Fig.2).Case 2: is not balanced.There are places 0, 0∈N with 0< 0such that is not { 0, 0}-balanced,that is,there are inﬁnite number of places > 0which are not { 0, 0}-balanced.Then,we ﬁnd an inﬁnite subset N ⊂{ 0+1, 0+2,...}such that for any ∈N ,both { 0, 0}-words either in {00,01}or in {10,11}are -special.Without loss of generality,we assume that both { 0, 0}-words in {00,01}are -special for inﬁnitely many ∈N .Collecting all these ,we deﬁne an inﬁnite set N ⊂N such that both { 0, 0}-words in {00,01}are -special for any ∈N ,while { 0, 0}-words in {10,11}are not -special for ∈N .Denote by and ∗the N -extensions of {00,01}and {10,11},respectively.More precisely,={ N (w);w ∈ such that { 0, 1}(w)∈{00,01}},∗={ N (w);w ∈ such that { 0, 1}(w)∈{10,11}}.We claim that is again a pattern Sturmian set.To see this,we study the set ∗ﬁrst.Since any { 0, 1}-word in {10,11}has a unique N -extension,# ∗ 2.Moreover,since { 0, }( )={00,01,10,11}for any ∈N ,the -extensions of 10and 11are different,thus ∗={x,x }for some N -word x .Hence,for any ﬁnite subset S ⊂N ,{ 0}∪S ( )={0w ;w ∈ S ( )}∪{1u,1u }for some S -word u .From this,we havep (S)=p ({ 0}∪S)−2=2(#S +1)−2=2#S ,being a pattern Sturmian set.Subcase 2.1:If is balanced,then by Case 1,there is an N such that (N )≈ 1.But for any S ⊂N , S ( (N ))⊂ S ( (N )),and since both (N )and (N )are pattern Sturmian,by comparing the cardinality, S ( (N ))= S ( (N )).Therefore,the preﬁx trees of (N )and (N )are just the same,and (N )≈ (N )≈ 1.Subcase 2.2:If is not balanced,then there exist 1, 1∈N with 1< 1such that is not { 1, 1}-balanced,and we get a new pattern Sturmian set ,and continue the above discussion.In case of the new pattern Sturmian set constructed in some step is balanced,then just as shown in Subcase 2.1,we ﬁnd N ⊂N such that (N )≈ 1.Otherwise,if all the pattern Sturmian sets constructed in the process are balanced,we get a sequence 0< 1< 2<···.PuttingN ={ 0, 1, 2,...},we have (N )≈ 2(see Fig.3).Example 3.6.Let ˜ ⊂{0,1}Z be the set of words ˜ on the index set Z such that either ˜ is increasing or ˜ is Dirac.Deﬁne a word (˜ )∈{0,1}N by(˜ )(k)=˜ (i)if k =2i is even ,˜ (−i)if k =2i −1is odd .Let = (˜ ).Then, is a pattern Sturmian set such that (N )= 2if N ={0,2,4,...}and (N )= 1≈ 1if N ={1,3,5,...}.Hence, is not primitive.Moreover,as shown in Fig.4, is isomorphic neither to 1nor to 2,so that [ ]is not primitive.1660T.Kamae et al./Discrete Mathematics306(2006)1651–1668Fig.4. in Example3.6.4.Structures of pattern Sturmian words4.1.From pattern Sturmian words to pattern Sturmian setsRecall that a word on N is called recurrent if for any L 1,there exists M 1such that(i)= (i+M)for i=0,1,...,L−1.(1) Note that if is recurrent,then there exist inﬁnitely many M’s satisfying(1).In this subsection,we will show how to construct pattern Sturmian sets from a recurrent pattern Sturmian word.Let be a pattern Sturmian word.For aﬁnite or inﬁnite subset N⊂N,consider the following property(we will call it the optimal property):for any nonemptyﬁnite subset ⊂N,it holds thatp ( )=2# .(2) If an inﬁnite subset N of N has the optimal property,then N is called an optimal window for .We note that an inﬁnite subset of an optimal window is again an optimal window.Theorem4.1.Let be a recurrent pattern Sturmian word.Then,there exists an optimal window for .Proof.Suppose that is a recurrent pattern Sturmian word.We construct an increasing family of sets satisfying the optimal property.Put n0=0.Assume that n0<n1<···<n k−1have been picked out such that the optimal property holds for the set := {n0,n1,...,n k−1}.Take L∈N such thatF ( )={ [n+ ];n=0,1,...,L−1}.Since is recurrent,there exists M with M>n k−1such that(1)holds for this L.Put n k=M.Now we show that(2)holds for any nonempty ⊂{n0,n1,...,n k}.•If n k/∈ ,(2)holds for by the hypothesis of induction.•If n k∈ but n0/∈ .Write ={n0}∪( \{n k}).Then# =# .Note that(2)holds for by the hypothesis of induction,actually#{ [n+ ];n=0,1,...,L−1}=#F ( )=2# .On the other hand,by(1), (n k)= (n0)for n=0,1,...,L−1.Therefore,there is an one-to-one correspondence between the sets{ [n+ ];n=0,1,...,L−1}。

2017年第八届山东大学学生五·四青年科学奖评选获奖人

任中飞，许醒等Integration of adsorption and direct bio-reduction of perchlorate on surface of cotton stalk based resin JOURNAL OF COLLOID AND INTERFACE SCIENCE，2015.12.1，第459期127–135页（SCI收录，IF 3.782）
2.Xin Huang, Baoyu Gao*, Yan Wang, Qinyan Yue, Qian Li, Yingying Zhang, Coagulation performance and ﬂocs properties of a new composite coagulant: Polytitanium–silicate–sulfate, Chemical Engineering Journal 245 (2014) 173–179 . (SCI收录，IF=5.310)
7.Xin Huang, Baoyu Gao*, Qinyan Yue, Yingying Zhang, Shenglei Sun, Compound bioflocculant used as a coagulation aid in synthetic dye wastewater treatment: The effect of solution pH, Separation and Purification Technology 154 (2015) 108–114. (SCI收录，IF=3.299)
2、其它学术科研成果：
①第十五届“挑战杯”山东大学课外学术科技作品竞赛三等奖（新型固定态纳米TiO2转盘石墨电极类电芬顿技术与好氧颗粒污泥SBR联合反应器深化处理污染物），杨航，2017，共青团山东大学委员会

抗生素PPT课件英文精品Antibioticresistanceanew

reduce the need of antibiotics through disease prevention
Hans Wolf-Watz, professor, UCMR, MIMS, Department of Microbiology, UmeåUniversity, Sweden, www.ucmr.se, www.molbiol.umu.se
EU: international leading research on molecular mechanisms of microbial
pathogenesis
Areas of research that will have the highest probability to solve the antibiotic resistance problem: • Anti virulence strategies to disarm infectious bacteria • Functional genomics - targeted drug design • Continue high throughput screening of natural products • Novel vaccines based on meta-genomics • Therapeutic antibodies • Antibacterial peptides
Methicillin-resistant S. aureus (MRSA) - most common multidrug resistant bacterium in EU
MRSA in Europe 2006. S.aureus: Proportion of invasive isolates resistant to oxacillin (MRSA) in 2006. * These countries did not report any data or reported less than 10 isolates, Source: http://www.earss.rivm.nl, March 2008

基于不对称螺二芴芳胺类蓝光发光材料的合成与性能研究

36韩蒙蒙等基于不对称螺二芴芳胺类蓝光发光材料的合成与性能研究基于不对称螺二芴芳胺类蓝光发光材料的合成与性能研究*韩蒙蒙2，陈鹏丽1，李瑞1，屈凤波1，邓书洋1,3，杨振强1὇1 河南省科学院化学研究所有限公司Ὃ河南郑州450002὚2 河南省科学院化学研究所Ὃ河南郑州450002὚3 河南师范大学材料科学与工程学院Ὃ河南新乡453007Ὀ摘要：螺二芴衍生物作为蓝光发光材料被广泛应用于有机发光半导体（OLED ）器件。

以螺二芴为母体，在2,7位分别引入具有空穴迁移率高的二苯胺和三苯胺基团，设计合成了不对称的螺二芴芳胺类发光材料7-(4-(二苯胺)苯基)-N,N-二苯-9,9'-螺二芴-2-胺。

研究表明，该化合物具有较高的热稳定性，其荧光发射波长为445nm ，位于蓝光区域。

同时具有高度扭曲的分子结构，有利于抑制分子间相互作用和自聚集，有效抑制非辐射，可应用于构建高效的有机蓝光发光材料。

关键词：螺二芴；合成与表征；蓝光发光材料中图分类号：O 625Synthesis and Properties of Asymmetric Spirobiﬂ uorene Arylamine Blue Emission MaterialsHAN Meng-meng 1,2, CHEN Peng-li 1, LI Rui 1, QU Feng-bo 1, DENG Shu-yang 1,3, YANG Zhen-qiang 1(1 Henan Academy of Sciences Institute of Chemistry Co., Ltd, Zhengzhou 450002, Henan, China; 2 Henan Academy of Sciences Institute of Chemistry, Zhengzhou 450002, Henan, China; 3 School of Materials Science and Engineering, Henan Normal University,Xinxiang 453007, Henan, China)Abstract: Spirodiapyrene derivatives are widely used as blue-emission materials in organic light-emitting semiconductor (OLED) devices. The asymmetric spirodifluorene arylamine luminescent material 7-(4-(diphenylamine)phenyl)-N,N-diphenyl-9,9'-spirodifluorene-2-amine was designed, and synthesized by using spirobifluorene as the core, and the diphenylamine and triphenylamine groups with high hole mobility were introduced at positions 2 and 7, respectively. It is proven that the compound has high thermal stability, and its ﬂ uorescence emission wavelength is 445 nm, located in the blue light region. At the same time, it has a highly distorted molecular structure, which is conducive to inhibiting intermolecular interaction and self-aggregation, inhibiting non-radiation eﬀ ectively, and can be applied to the construction of eﬃ cient organic blue-luminescent materials.Key words: spirobiﬂ uorene; synthesis and characterization; blue emission luminescent materials *基金项目：河南省科学院科研启动费项目（231818024）；河南省科学院特聘研究员项目（230503006）；河南省科学院重大科研项目聚焦项目（210103001）。

无患子皂苷－十二烷基苯磺酸钠复配体系表面活性及在制备氢氧化镍复合材料中的应用

无患子皂苷－十二烷基苯磺酸钠复配体系表面活性及在制备氢氧化镍复合材料中的应用詹舒辉;李娟;刘泽学;徐永霞;李保同;韩春蕊【摘要】Surface activity of Sapindus mukurossi saponin and sodium dodecyl benzene sulfonate (SBDS)blend system was examined,and the blends were used to prepare nickel hydroxide composites. The composites were characterized with X -ray diffraction (XRD)and scanning electron microscope (SEM). Influence of the surfactant on morphology of the composites was investigated. Results revealed that the critical micelle concentration (cmc)and the surface t ension (γcmc )of the extracted Sapindus mukurossi saponin are 0.200 g/L and 38.3 mN/m respectively. The blend system displays synergic effect when mass fraction of SDBS achieves 5%,while confrontation effect when mass fraction of SDBS is more than 20%. Using the blend system composed of 5% SDBS as additive at dosage of 0.83 g/L,homogeneous morphological microspheres of nickel hydroxide composites with average diameter of 3 μm can be successfully prepared.%研究了无患子皂苷与十二烷基苯磺酸钠（SDBS）复配体系的表面活性，并将其应用于氢氧化镍复合材料的制备中；采用X射线衍射（XRD）和扫描电镜（SEM）对复合材料进行了结构表征，考察了表面活性剂对材料形貌的影响。

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