Miracle-dz/UniFAR-FTUs huggingface dataset:
Sulfonated Polyimides for Polymer Electrolyte Membrane Fuel Cell

Two types of novel sulfonated diamines bearing sulfonic acid groups directly bonded to polyimide main chains (main-chain type) or in the side alkoxy chains (side-chain type), and the corresponding sulfonated polyimides were successfully synthesized. Water vapor sorption, proton conductivity σ, methanol permeability PM, membrane stability toward hot water, and size change with water uptake of the sulfonated polyimide membranes were investigated. The membranes of sulfonated polyimides prepared on the basis of the proper molecular design showed much better water stability and higher proton conductivity compared with the conventional polyimides based on 2,2'-benzidinedisulfonic acid. They also displayed the higher ratio of σ over PM than Nafion 117 membrane. They might have potential for polymer electrolyte fuel cell and methanol direct fuel cell applications.
Cavitation phenomena and the occurrence of pressure-tension cycles under dynamic stressing

Two different methods of subjecting a liquid to tension under dynamic conditions are described. In the first method a tension pulse is created ab initio in a column of water and the resulting pressure-tension cycles are monitored by a pressure transducer. These cyclic pressure variations have been observed by earlier workers but no adequate explanation of their occurrence has been previously given; such an explanation is proposed in the present paper. Secondly, a development of the bullet-piston method used by Couzens and Trevena (1974) is described in which a new way of obtaining and presenting the experimental results is reported.
The accuracy of a commercial spectrophotometer with single integrating sphere for measuring optical properties of turbid sample

A commercial spectrophotometer with an integrating sphere is widely used to measure the spectra of transmittance and reflectance of turbid sample, and then the optical properties can be deduced by inverse adding-doubling algorithm. Unfortunately, the accuracy of the measurement is not been elucidated completely. What's more, for the system, there still exists some other limits, i.e., the incident light is not collimated and size of light spot is too large compared with the sample port. Thus, the purpose of our study is to evaluate the accuracy of the commercial spectrophotometer with an integrating sphere for measuring optical properties of tissue phantom. Two phantom materials, Intralipid and Evans blue, and the mixture of these two, were chosen for the experiments. Mie theory was also introduced to calculate the reduced scattering coefficient according to the particle size distribution. The results show that the phantom measurement in conjunction with IAD algorithm enable the determination of scattering coefficient μs' to be better than 5% accuracy, absorption coefficient μa to be better than 10% accuracy when the optical depth of sample is between 1 and 10, and the albedo is bigger than 0.4. For scattering of samples during 1-5 mm-1, the error of μs' is smaller than 4%; whereas for absorbing of samples >0.4 mm-1, the maximum error is smaller than 8.3%. Therefore, spectrophotometer with an integrating sphere technique combined IAD algorithm is applicable for the measurements of optical properties for most tissue, and its repeatability and accuracy is good in proper scope of the optical depth and albedo.
Evolution of an Ensemble of Nanoparticles in a Colloidal Solution: Theoretical Study

The evolution of a nanosized particle in colloidal solution has been studied theoretically. The model developed is based on the size dependence of the activation energies of the growth and dissolution processes and takes into account the mass transport dynamics. Using this model, Monte Carlo simulations of the evolution of an ensemble of growing nanoparticles during Ostwald ripening have been performed, and conditions leading to either “focusing” or “defocusing” of the particle size distribution were found. The stationary particle size distribution inherent to the Ostwald ripening process in ensembles of nanoparticles less than 5 nm in radius is narrower and more symmetric than that predicted by the Lifshitz−Slyozov−Wagner theory valid for ensembles of larger (>20 nm in radius) colloidal particles. The growth of nanoparticles in the diffusion-controlled regime results in better final size distributions as compared with those grown in the reaction-controlled regime. The dependence of the particle size dist.
A study on the effects of twin boundaries and surface morphology on deformation behaviours of silver nanowires

Nanoscale twin boundaries (TBs) and surface morphology play a significant role in the yield behaviour of nanowires (NWs). However, few studies have directly compared their effects on the mechanical response of metal NWs. In this article, the mechanical properties of three 〈1 1 1〉 silver NWs with a diameter of 12.2 nm are studied using molecular dynamics simulations. The 〈1 1 1〉 silver NWs are single crystalline rectangular NWs (SCNW), twinned rectangular NWs (TRNW) and faceted twinned NWs (FTNW), respectively. Comparing SCNW and the twinned NWs, we found that a superior combination of higher strength and elasticity was achieved in the twinned NWs by introducing the TBs in elastic region. Then, we also found that the yield strain of FTNW have a strong dependence on TB spacing. Furthermore, a comparison of the incipient plastic deformation between TRNW and FTNW has been made by monitoring defects evolution. To identify the defects evolution, a centrosymmetry parameter was defined and implemented in the self-developed program. And we also compared the effect of TB and surface morphology on mechanical response of three silver NWs. In general, it can be concluded that TBs significantly influence the mechanical properties of metallic NWs and it is more essential than surface morphology.
The influence of adsorbent microstructure upon adsorption equilibria : investigations of a model system

We present a theoretical study of the influence of the microstructure of a porous adsorbent upon associated adsorption behavior. A model is developed which describes the interactions of adsorbed molecules with an adsorbent treated as a matrix of particles each of which is a continuum of interaction centers. The model leads to an analytic expression for the adsorbate‐adsorbent particle potential which is an analog of the 9‐3 potential model for adsorption on planar solid surfaces. To illustrate the utility of the approach, an application to methane adsorbed in a microporous silica gel is presented. Several adsorbent microstructures are investigated, including a variety of crystal lattices as well as structures derived from equilibrium configurations of hard spheres. Adsorption in these structures is studied through calculation of Henry’s law constants and by using grand canonical Monte Carlo simulation to determine adsorption isotherms and the structure of adsorbed fluids. The results obtained are related .
Precision synthesis of a fluorinated polyhedral oligomeric silsesquioxane-terminated polymer and surface characterization of its blend film with poly(methyl methacrylate)

Incompletely condensed, fluorinated polyhedral oligomeric silsesquioxane with the highly reactive group of trisodium silanolate was used for the synthesis of an initiator for atom transfer radical polymerization. The initiator was applied to solution polymerization of methyl methacrylate (MMA) in the presence of a copper complex. The polymerization proceeded in a living fashion, providing tadpole-shaped polymers with an “inorganic head” of polyhedral oligomeric silsesquioxane (POSS) and an “organic tail” of well-defined PMMA. A blend film composed of the tadpole-shaped polymer and a matrix PMMA was annealed at 180 °C for 5 days and then analyzed by neutron reflectometry, X-ray photoelectron spectroscopy, and contact angle measurement. These analyses revealed that the tadpole-shaped polymer was preferentially populated at the air/polymer interface, and the outermost layer of the film was almost completely covered by the POSS heads. This was mainly due to the low surface free energy of the fluorinated POSS .
Terrestrial biogeochemical cycles: global interactions with the atmosphere and hydrology

Ecosystem scientists have developed a body of theory to predict the behavior of biogeochemical cycles when exchanges with other ecosystems are small or prescribed. Recent environmental changes make it clear that linkages between ecosystems via atmospheric and hydrological transport have large effects on ecosystem dynamics when considered over time periods of a decade to a century, time scales relevant to contemporary humankind. Our ability to predict behavior of ecosystems coupled by transport is limited by our ability (1) to extrapolate biotic function to large spatial scales and (2) to measure and model transport. We review developments in ecosystem theory, remote sensing, and geographical information systems (GIS) that support new efforts in spatial modeling. A paradigm has emerged to predict behavior of ecosystems based on understanding responses to multiple resources (e.g., water, nutrients, light). Several ecosystem models couple primary production to decomposition and nutrient availability using the above paradigm. These models require a fairly small set of environmental variables to simulate spatial and temporal variation in rates of biogeochemical cycling. Simultaneously, techniques for inferring ecosystem behavior from remotely measured canopy light interception are improving our ability to infer plant activity from satellite observations. Efforts have begun to couple models of transport in air and water to models of ecosystem function. Preliminary work indicates that coupling of transport and ecosystem processes alters the behavior of earth system components (hydrology, terrestrial ecosystems, and the atmosphere) from that of an uncoupled mode. DOI: 10.1034/j.1600-0889.1991. t01-1-00017.x
The Statistical Mechanical Theory of Transport Processes. III. The Coefficients of Shear and Bulk Viscosity of Liquids

A molecular theory of the coefficients of shear and bulk viscosity of monatomic liquids is developed on the basis of the general theory of transport processes presented in the first article of this series. With the use of the Lennard-Jones potential and a reasonable analytic approximation to the experimental radial distribution function, calculations of the coefficients of shear and bulk viscosity of liquid argon at 89°K have been carried out. The theory leads explicitly to ratios of the coefficients to the friction constant of the theory of Brownian motion. With a preliminary estimate of the friction constant, a value of the shear viscosity of liquid argon in moderately good agreement with experiment is obtained.
Targeted drugs by olefin metathesis: piperidine-based iminosugars

Examining advances in the class of natural and non-natural piperidine azasugars, important therapeutic agents and potent glycosidase inhibitors, this review looks at syntheses applying olefin metathesis as a highly efficient key step and gateway strategy for discovery of better iminosugar leads for treatment of widespread affections like viral and metabolic diseases. Amply illustrated is how ring-closing metathesis (RCM and RCEYM), promoted by commercial ruthenium alkylidene catalysts, manage to construct the common tetrahydropyridine core while cross-metathesis (CM), starting from this generic scaffold, provides general access to families of novel azasugars. Special consideration is given to high-profile iminosugar drugs of this class (1-deoxynojirimycin and congeners, adenophorine, fagomine, isofagomine and some of their N- and C-substituted analogues) stressing upon newest trends for enhancing biological activity and modulating previously unexploited targets in multispecific therapies.
Preparation of Size-Controlled Silver Nanoparticles and Chitin-Based Composites and Their Antimicrobial Activities

A simple method for the preparation of size-controlled spherical silver nanoparticles (Ag NPs) was reported for their generation by autoclaving a mixture of silver-containing glass powder and glucose. The particle size is regulated by the glucose concentration, with concentrations of 0.25, 1.0, and 4.0 wt% glucose providing small ( nm in diameter), medium ( nm), and large ( nm) particles, respectively. In this study, Ag NP/chitin composites were synthesized by mixing each of these three Ag NP suspensions with a <5% deacetylated (DAc) chitin powder (pH 7.0) at room temperature. The Ag NPs were homogenously dispersed and stably adsorbed onto the chitin. The Ag NP/chitin composites were obtained as yellow or brown powders. Approximately 5, 15, and 20 μg of the small, medium, and large Ag NPs, respectively, were estimated to maximally adsorb onto 1 mg of chitin. The bactericidal and antifungal activities of the Ag NP/chitin composites increased as the amount of Ag NPs in the chitin increased. Furthermore, smaller Ag NPs (per weight) in the chitin composites provided higher bactericidal and anti-fungal activities.
Chemical and leaching properties of paper mill sludge

Abstract Paper mills produce large amounts of paper mill sludge in the treatment of process water. According to overburden studies, the hydraulic conductivity of the paper mill sludge originating from a paper mill in Northern Finland at a pressure of 30kPa was 4.4×10∓10 ms∓1, and 1.7×10∓ 10 ms∓1at a pressure of 100kPa. These values well meet the generally required values of between 1.0×10∓7 ms∓1 and 1.0×10∓9 ms-1 for a geological barrier in landfill base and sides at landfills in the European Union. Paper mill sludge can also be used in the artificially constructed geological barrier layer of landfill cover structures. The angle of internal friction of the paper mill sludge was 34.8° and the cohesion of inter-particle adhesion 23 kPa, which are important measures for assessing the shear strength of paper mill sludge and thus the stability of the landfill layer in which it is used. During a 28-day period, the biodegradability of the paper mill sludge in soil was ca 0.4% and in ground water under 1%, whereas according to the OECD 301F standard concentrations (BOD28), it was ca 8%. For the determination of total element concentrations in the paper mill sludge, the dried sample was digested using USEPA method 3052. A five-stage sequential leaching procedure was also used to fractionate trace elements in the paper mill sludge between the water-soluble (H2O), exchangeable (CH3COOH), easily reduced (HONH3CD, oxidizable (H2O2 + CH3COONH4), and (5) the residual (HF + HNO3 + HCl) fractions. This paper covers also examples of case studies how paper mill sludge is utilized in Finland.
Swelling of the Zwitterionic Copolymer Networks and Dehydration of their Hydrogels

The polyelectrolyte and antipolyelectrolyte effects on the degree of swelling (Q) and dehydration activation energy (E a ) of homo- and copolymer single and double networks, consisting of monomer units with polyelectrolyte and antipolyelectrolyte association abilities are determined and compared. An original correlation between Q and E a is outlined and explained.
Synthesis, Characterization, and Biocompatibility of Polyethylenimine-graft-poly(ethylene glycol) Block Copolymers

Two series of block copolymers were prepared by grafting linear poly(ethylene glycol) (PEG) onto branched polyethylenimine (PEI). In the first series, the PEI (25 000) was grafted with varied numbers of PEG blocks (5000). The second series was composed of copolymers all containing an equal amount of PEG (50%) and PEI (50%), but with PEG of different molecular weights (MW: 550−20 000). In a two-step synthesis, both the activation of monomethyl-PEGs and the coupling reactions of the PEGs with PEI were performed with hexamethylene diisocyanate (HMDI), leading to water-soluble copolymers with hydrolytically stable urethane and urea bonds. The molecular structure of the resulting copolymers was evaluated spectroscopically (NMR, FTIR). Thermal and calorimetric analysis (TGA, DSC) as well as size exclusion chromatography (SEC) verified the successful formation of the copolymers. MW was determined by static light scattering in combination with SEC. With respect to their application as gene transfer agents, the b.
A Singlet Oxygen Image with 2.5 μm Resolution

Upon irradiation of a photosensitizer, singlet molecular oxygen has been detected via its a1Δg → X3Σg- phosphorescence with a microscope. Using this tool, a singlet oxygen image with 2.5 μm resolution has been constructed of a phase-separated toluene/water mixture. For the a → X transition at ∼ 7850 cm-1 (∼ 1270 nm), a lateral resolution of 2.5 μm is close to the diffraction limit of ∼1.5−2.0 μm.
Improved Synthesis of Monoprotected 5- and 6-Amino-2-azanorbornanes

Abstract An improved synthesis of Boc-monoprotected 5- and 6-amino-2-azanorbornanes is reported. The synthetic scheme consists of five steps and allows multigram quantities of the title compounds to be obtained. The regio- and stereochemistries of the products are established by two-dimensional NMR experiments.
Physical Properties of the Biodegradable Polymer Compositions Containing Natural Polyesters and their Synthetic Analogues

The thermal, mechanical and thermo-mechanical properties of polymer compositions, containing synthetic biodegradable polymers i.e. polylacide (PLA) and aliphatic-aromatic copolyester (BTA), natural biopolyester n-PHB and its synthetic atactic analog (a-PHB) were investigated. Thermal properties of the polymer compositions were studied by means of DSC. The compositions of various polymer weight ratio were tested. Compositions containing BTA and n-PHB create polyphase systems, what was confirmed by DSC. In this case the two Tg and two Tm values were observed. Polymer compositions containing PLA and BTA showed different behaviours. At the BTA content up to 30 weight % only one Td one Tm were indicated. At the increase of the BTA content to 50% weight and above, the two Tg, and two Tm were observed. Mixtures of BTA with n-PHB, PLA and with a-PHB show considerably greater values of the strain (e) in comparison with initial polymers (n-PHB, PLA). It was found that in contrary to mixtures containing PLA, at the BTA content in the mixture with n-PHB above 50% of weights increases not only the strain, but also the stress at break (σ). Strong increase of the e value in PLA/a-PHB mixtures with the content of a-PHB above 30% of weights were observed.
Practical production of 61Cu using natural Co target and its simple purification with a chelating resin for 61Cu-ATSM

Abstract Copper-61 (T1/2=3.41 h) produced via the 59Co(α,2n)61Cu nuclear reaction using natural Co target was isolated from the irradiated target by two methods developed here and applied for preparation of (61Cu-ATSM) (61Cu-diacetyl-bis(N4-methylthiosemicarbazone)), known as an imaging agent of hypoxic tissue. A commercially available cobalt disk (thickness: 125 μm) was irradiated with 40 MeV (37.9 MeV on target) α particles, then treated with conc. HNO3, and the 61Cu was separated by two different methods, i.e. a two column method using a cation and an anion exchange column; and a one column method using a column packed with chelating resin, Chelex 100. Both separation methods gave satisfactory results, though the latter method was superior because of the simplicity of the apparatus, the separation procedure and somewhat shorter processing time. Around 1.1 GBq of 61Cu2+ were obtained with >95% yield (decay corrected) from Co target at 10 μA for 1 h irradiation, and with the radionuclidic purity of >98% (EOS). The only radionuclidic impurity in the isolated 61Cu2+ solution was identified to be 60Cu at EOS but no radionuclidic impurity was observed after 50 hours. The solution of 61Cu-ATSM was prepared in >85% radiochemical yield with >95% radiochemical purity.
Direct Monte Carlo simulation of the chemical equilibrium composition of detonation products

A new Monte Carlo simulation method has been developed by the author which gives the equilibrium chemical composition of a molecular fluid directly. The usual NPT ensemble (isothermal-isobaric) is implemented with N being the number of atoms instead of molecules. Changes in chemical composition are treated as correlated spatial moves of atoms. Given the interaction potentials between molecular products, ``exact`` EOS points including the equilibrium chemical composition can be determined from the simulations. This method is applied to detonation products at conditions in the region near the Chapman- Jouget state. For the example of NO, it is shown that the CJ detonation velocity can be determined to a few meters per second. A rather small change in cross potentials is shown to shift the chemical equilibrium and the CJ conditions significantly.
Simple atomistic modeling of dominant B m I n clusters in boron diffusion

In this paper, we present a simple atomistic model for describing the evolution of interstitial clusters during boron diffusion in kinetic Monte-Carlo (KMC) calculation. It has been known that clusters generated after ion implantation play a decisive role in the enhanced boron diffusion at the tail region while being immobile at the peak region. Our model, which is based on the simple continuum model, takes the intermediate clusters into account as well as dominant clusters for describing the evolutionary behavior of interstitial clusters during boron diffusion. We found that the intermediate clusters such as B3I3 and B2I3 play a significant role during the evolution of clusters despite the fact that the lifetimes of the corresponding intermediate clusters are relatively short due to low binding energies. Further, our investigation revealed that B3I is the most dominant cluster after annealing. We applied our simple atomistic model to the study of boron retardation in arsenic pre-doped substrate. KMC simulation results were compared with experimental SIMS data, which supports our theoretical model.
Novel synthesis of diketocarboxymethyl-celluose as bipolymer precursors

2,3-Diketocarboxymethylcellulose was prepared by the oxidation of carboxymethylcellulose (CMC) with potassium permanganate in alkaline solutions (pH ≥ 12) with a yield of 98.1%. IR spectroscopy and microanalysis have elucidated the chemical structure of the synthesized macromolecule (CMCK). A tentative reaction mechanism for oxidation is suggested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1019–1023, 2002
Au–Cu alloy nanoclusters in silica formed by ion implantation and annealing in reducing or oxidizing atmosphere

The formation of binary alloy clusters in sequentially ion-implanted Au–Cu silica glass has been studied as a function of the annealing atmosphere. Alloy formation has been unambiguously evidenced in the as-implanted samples. The selective influence on Au precipitation of either oxygen or hydrogen annealing atmosphere leads to separation of gold and copper or to Au–Cu alloy cluster formation, respectively.
Conditional histogram analysis of discrete questionnaire data

The paper deals with the analysis of histograms of discrete data collected in questionnaires obtained for individual realizations of the target variable. The main aim of the analysis is to explore the influence of combinations of explanatory variables, represented by responses to the questionnaire, on the behavior of the target variable of the questionnaire. In this paper, an automated approach to histogram comparison is proposed based on coding combinations of data and detecting significant differences in frequencies using the Marascuilo procedure. This is the main contribution of the paper. The approach is validated using a simulated questionnaire in which respondents answered regarding their intention to purchase an electric vehicle subject to finance, leasing, and charging availability, as well as their driving style. The results of the experiments are demonstrated.