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PRODUCTION OF POLYCYCLIC AROMATIC-HYDROCARBONS IN CHLORINE CONTAINING ENVIRONMENTS

COMBUSTION science AND TECHNOLOGY 1990年第1-6期74卷 283-296页

作者： FRENKLACH, M Fuel Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802

The factors affecting the formation and growth of polycyclic aromatic hydrocarbons (PAHs) in chlorine-containing environments are investigated. The experimental results obtained in shock-tube pyrol-ysis of chlorinated C1, and C2, hydrocarbons are re-analyzed in terms of Cl-to-H molar ratio of the mixture and it is found that the sooting tendency and hence PAH production are increased with the increase in [C1]/[H] ratio. Based on the analysis of the reaction kinetics and results or detailed modeling, two basic factors are suggested to be responsible for this phenomenon: (1) the enhanced, chlorine-catalized molecular degradation that promotes the formation of aromatic-ring compounds; and (2) the large concentration of CI atoms that accelerates the abstraction of aromatic H from stable PAH molecules, which activates them for further growth. The modeling results also provide an evidence against existence of a correlation between PAHs and CO in flame environments.

关键词： POLYCYCLIC AROMATIC HYDROCARBONS SOOT CHLORINATED HYDROCARBONS

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Sulfur and nitrogen codoped cyanoethyl cellulose-derived carbon with superior gravimetric and volumetric capacity for potassium ion storage

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Carbon Energy 2022年第5期4卷 986-1001页

作者： Guangzeng Cheng Wenzhe Zhang Wei Wang Huanlei Wang Yixian Wang Jing Shi Jingwei Chen Shuai Liu Minghua Huang David Mitlin School of Materials Science and Engineering Ocean University of ChinaQingdaoShandongChina Materials Science and Engineering Program Texas Materials Institute(TMI)The University of Texas at AustinAustinTexasUSA

We fabricated sulfur and nitrogen codoped cyanoethyl cellulose-derived carbons(SNCCs)with state-of-the-art electrochemical performance for potassium ion battery(PIB)and potassium ion capacitor(PIC)*** 0.2,0.5,1,2,5,and 10 A g−1,the SNCC shows reversible capacities of 369,328,249,208,150,and 121 mA h g−1,*** to a high packing density of 1.01 g cm^(−3),the volumetric capacities are also uniquely favorable,being 373,331,251,210,151,and 122 mA h cm^(−3)at these currents,*** also shows promising initial Coulombic efficiency of 69.0%and extended cycling stability with 99.8%capacity retention after 1000 *** proof of principle,an SNCC-based PIC is fabricated and tested,achieving 94.3Wh kg^(−1)at 237.5Wkg^(−1)and sustaining over 6000 cycles at 30 A g−1 with 84.5%*** internal structure of S and N codoped SNCC is based on highly dilated and defective graphene sheets arranged into nanometer-scale *** a baseline S-free carbon for comparison(termed NCC),the role of S doping and the resultant dilated structure was *** to galvanostatic intermittent titration technique and electrochemical impedance spectroscopy analyses,as well as COMSOL simulations,this structure promotes rapid solid-state diffusion of potassium ions and a solid electrolyte interphase that is stable during cycling.X-ray diffraction was used to probe the ion storage mechanisms in SNCC,establishing the role of reversible potassium intercalation and the presence of KC36,KC24,and KC8 phases at low voltages.

关键词： carbon manufacturing commercial carbon graphene potassium ion battery(KIP,PIB) potassium ion storage

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THE CHAIN-LENGTH DEPENDENCE OF THE CHEMICAL-POTENTIALS OF MACROMOLECULAR SYSTEMS AT ZERO DENSITY - EXACT CALCULATIONS AND MONTE-CARLO SIMULATIONS

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JOURNAL OF CHEMICAL PHYSICS 1992年第2期96卷 1490-1497页

作者： KUMAR, SK Department of Materials Science and Engineering Polymer Science Program Pennsylvania State University University Park Pennsylvania 16802

In a previous paper we illustrated a Monte Carlo method to calculate the incremental chemical potential between polymer chains of length nu and nu + 1 at all densities. In this document we present a statistical mechanics model that allows for its quantitative evaluation as a function of chain length and temperature for macromolecular systems at zero density. Through this approach the incremental chemical potential at zero density is shown to be a strong function of chain length at low temperatures, but becomes chain length independent even for short chains (nu greater-than-or-equal-to 3) at higher temperatures. The temperature where the chemical potential becomes essentially chain length independent is a definition of the Boyle transition for finite chain length polymers, and we show that this transition temperature has a well defined chain length dependence. Chain dimensions and incremental entropies associated with chain segments are also found to decrease significantly when the temperature is reduced below this theta-temperature thus providing that chain segments are localized in the vicinity of other segments in the collapsed state. The consequences of these results on the modeling of the phase equilibria of polymer solutions are also examined.

关键词： CHAINS LENGTH CHEMICAL POTENTIAL MACROMOLECULES DENSITY MONTE CARLO METHOD SIMULATION CALCULATION METHODS POLYMERS THERMODYNAMICS

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POLYMER PIEZOELECTRIC CERAMIC COMPOSITES - POLYSTYRENE AND POLY(METHYL METHACRYLATE) WITH PZT

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JOURNAL OF APPLIED POLYMER science 1984年第2期29卷 611-617页

作者： RUNT, J GALGOCI, EC Polymer Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park Pennsylvania 16802

AbstractLead zirconate–titanate (PZT)/polymer composites have been prepared byin situpolymerization of styrene and methyl methacrylate around aligned, thin PZT rods. Hydrostatic piezoelectric coefficients (d̄hand ḡgh) measured by a dynamic technique yielded figures of merit (d̄hḡh) roughly four times that of homogeneous PZT for as‐polymerized composites. When these composites were annealed at a temperature slightly below the glass transition temperature of the matrix polymer and repoled, d̄hḡhincreased nearly twofold due primarily to a reduction of the composite dielectric constant. The piezoelectric response was found to be essentially independent of frequency from

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Structural properties of hyperuniform Voronoi networks

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Physical Review E 2025年第3期111卷 034123-034123页

作者： Eli Newby Wenlong Shi Yang Jiao Reka Albert Salvatore Torquato Department of Physics Pennsylvania State University University Park Pennsylvania 16802 USA Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered hyperuniform many-particle systems are recently discovered exotic states of matter, characterized by the complete suppression of normalized infinite-wavelength density fluctuations, as in perfect crystals, while lacking conventional long-range order, as in liquids and glasses. In this work, we begin a program to quantify the structural properties of nonhyperuniform and hyperuniform networks. In particular, large two-dimensional (2D) Voronoi networks (graphs) containing approximately 10,000 nodes are created from a variety of different point configurations, including the antihyperuniform hyperplane intersection process (HIP), nonhyperuniform Poisson process, nonhyperuniform random sequential addition (RSA) saturated packing, and both non-stealthy and stealthy hyperuniform point processes. We carry out an extensive study of the Voronoi-cell area distribution of each of the networks by determining multiple metrics that characterize the distribution, including their average areas and corresponding variances as well as higher-order cumulants (i.e., skewness γ1 and excess kurtosis γ2). We show that the HIP distribution is far from Gaussian, as evidenced by a high skewness (γ1=3.16) and large positive excess kurtosis (γ2=16.2). The Poisson (with γ1=1.07 and γ2=1.79) and non-stealthy hyperuniform (with γ1=0.257 and γ2=0.0217) distributions are Gaussian-like distributions, since they exhibit a small but positive skewness and excess kurtosis. The RSA (with γ1=0.450 and γ2=−0.0384) and the highest stealthy hyperuniform distributions (with γ1=0.0272 and γ2=−0.0626) are also non-Gaussian because of their low skewness and negative excess kurtosis, which is diametrically opposite of the non-Gaussian behavior of the HIP. The fact that the cell-area distributions of large, finite-sized RSA and stealthy hyperuniform networks (e.g., with N≈10,000 nodes) are narrower, have larger peaks, and smaller tails than a Gaussian distribution implies that in the thermodynamic limit th

关键词： Gaussian distribution

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An overview of high-throughput synthesis for advanced high-entropy alloys

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materials Genome engineering Advances 2025年第1期3卷

作者： Tong Xie Weidong Li Gihan Velisa Shuying Chen Fanchao Meng Peter K. Liaw Yang Tong Institute for Advanced Studies in Precision Materials Yantai University Yantai Shandong China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing Beijing China Horia Hulubei National Institute for Physics and Nuclear Engineering Bucharest Romania Department of Materials Science and Engineering University of Tennessee Knoxville Tennessee USA

High-entropy alloys (HEAs) have revolutionized alloy design by integrating multiple principal elements in equimolar or near-equimolar ratios to form solid solutions, vastly expanding the compositional space beyond traditional alloys based on a primary element. However, the immense compositional complexity presents significant challenges in designing alloys with targeted properties, as billions of new alloy systems emerge. High-throughput approaches, which allow the parallel execution of numerous experiments, are essential for accelerated HEA design to navigate this extensive compositional space and fully exploit their potential. Here, we reviewed how advancements in high-throughput synthesis tools have accelerated HEA database development. We also discussed the advantages and limitations of each high-throughput fabrication methodology, as understanding these is vital for achieving precise HEA design.

关键词： combinatorial thin-film synthesis diffusion multiples high-entropy alloys high-throughput directed energy deposition high-throughput synthesis

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Virtual enumeration and evaluation of thin-film monomers for potential membrane synthesis via interfacial polymerization

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Journal of Membrane science 2025年

作者： Lana Bader Gergo Ignacz Gyorgy Szekely Advanced Membranes and Porous Materials Center Physical Science and Engineering Division (PSE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Chemical Engineering Program Physical Science and Engineering Division (PSE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia

Many state-of-the-art applications, including membranes, adhesives, coatings, and sensors, are based on thin polymer films. The exploration of thin films can be facilitated by diversifying the chemical space of organic and aqueous monomers used in interfacial polymerization. To this end, we created a virtual library covering a range of scaffolds and fragments. First, we enumerated 137 scaffolds and 54 fragments to create more than 1.3 billion structures. We then filtered the raw library to remove duplicates and invalid structures. Further filtering based on molecular descriptors reduced the raw virtual library to a list of 26 million molecular structures as potential candidates for thin film formation via interfacial polymerization. The structures were further analyzed to identify their suitability as thin films where the solubilities, toxicities, and process mass intensities were calculated. In addition, the molecular structures in the virtual library were compared with those of commercially available monomers in the ZINC database. Overall, we could generate new structures with potential viability in thin film polymerization reactions. Our dataset can be utilized by the membrane community in molecular simulation studies, machine learning applications, and other data-extensive methods requiring a large and diverse set of molecules.

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A SPECTROSCOPIC STUDY OF NICKEL-OXIDE FILMS ON POLYCRYSTALLINE NICKEL

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THIN SOLID FILMS 1989年第1-2期177卷 171-180页

作者： MITRA, S TATTI, SR STARK, JP Materials Science and Engineering Program University of Texas at Austin Austin TX 78712 U.S.A.

The growth of nickel oxide films has attracted much attention over the years, and various diffusion mechanisms have been proposed to model the process. The popular techniques used to study the mass transport mechanisms have been Auger electron spectroscopy and secondary ion mass spectroscopy (SIMS). Another approach that has been suggested is the study of isotope separation during thin film growth. This type of analysis can give the mechanism of reaction during the film growth and is the technique used in this study. A normal isotope separation implies either grain boundary or lattice diffusion, whereas a reverse separation explicity implies grain boundary diffusion. This study looks at nickel oxides grown on polycrystalline nickel at 400, 600 and 800°C, and which range from 1.5 to 18 μm in thickness. Oxides were grown under atmospheric oxygen partial pressure conditions. X-ray diffraction was used to determine the nature of the oxide, and SIMS, in conjunction with Auger spectroscopy and argon ion sputtering, was used to determine the isotope separation if any. It was found that the oxide grown at 800°C exhibited reverse isotope separation, whereas the oxides grown at lower temperatures showed normal separation. Simplified calculations of the chemical diffusion coefficients of nickel in nickel oxide have also been made at the temperatures of interest, and activation energies ranging from 55.2 to 190.4 kJ mol -1 were obtained.

关键词： Nickel Compounds

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Chemical synthesis and coercivity enhancement of Nd2Fe14B nanostructures mediated by non-magnetic layer

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Nano Research 2020年第4期13卷 1141-1148页

作者： Kai Zhu Junjie Xu Xiaobai Wang Wei Li Kesong Tian Yanglong Hou Beijing Key Laboratory for Magnetoelectric Materials and Devices(BKLMMD) Beijing Innovation Centre for Engineering Science and Advanced TechnologyDepartment of Materials Science and EngineeringCollege of EngineeringPeking UniversityBeijing 100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China

High-performance Nd2Fei4B magnets have been widely required in various fields recently due to the lightweight and miniaturization of *** this work,we synthesize Nd2Fei4B nanostructures with tunable magnetic properties through surfactant-assisted high energy ball milling(SAHEBM)process,achieving prominently enhanced coercivity by forming non-magnetic layers as grain boundary *** the reduction annealing process was carried out as pellet with Ca,the coercivity increased from 0.8 kOe to over 3 kOe as Nd2Fei4B powder,which is proved to be the contribution of the chemical diffusion of Nd elements and the formation of Nd-rich layer as magnetic insulating *** addition,two-dimensional graphene oxide(GO)was employed to build extra grain boundary,by which the coercivity of the core@dual-shell structure can achieve up to 8 kOe,tenfold of the original *** intrinsic mechanism indicated that the Nd-diffusion induced Nd-rich phase along with the reduced GO in the system could form non-magnetic layer as grain boundary and magnetically isolate the adjacent grains,significantly enhancing the exchange coupling *** work markedly opens up an effective approach for the chemical preparation of high-performance Nd2Fe14B nanostructured magnets,especially after post treatment,and gives an insight on the interactions at nanoscale.

关键词： Nd2Fei4B nanostructures chemical reduction diffusion process grain boundary graphene oxide coercivity enchantment

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SMALL-ANGLE X-RAY-SCATTERING (SAXS) IN CARBONIZED PHENOLIC RESINS

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CARBON 1994年第5期32卷 953-960页

作者： GUPTA, A HARRISON, IR [a]Department of Materials Science Engineering Polymer Science Program The Pennsylvania State University University Park PA 16802 U.S.A.

Small-Angle X-ray Scattering (SAXS) has been used as an analytical tool to study the development of microstructure with increasing Heat Treatment Temperature (HTT) of a carbonized phenolic resin, which is often used as matrix in commercial carbon-carbon composites. Processing parameters-heating rate and maximum heat treatment temperature-were the primary variables of interest. Results from SAXS have led to the consideration of a model for microstructure development in carbonized phenolic resins. Local density variations on the 10 angstrom-100 angstrom scale seem to be the predominant feature of these carbonized resins in the temperature range studied (450-900-degrees-C). Heat treatment results in a gradual destruction of crosslinks, which leads to clustering of the aromatic units. These clusters enclose pores, the high concentrations of which give rise to scattering maxima in SAXS data. Concentration and dimensions of pores are sensitive both to the heating rate used and the maximum carbonization temperature.

关键词： CARBONIZED PHENOLIC RESIN SMALL-ANGLE X-RAY SCATTERING CLUSTERS MICROPOROSITY

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