Miracle-dz/UniFAR-FTUs huggingface dataset:
Self‐Consistent Molecular‐Orbital Methods. IX. An Extended Gaussian‐Type Basis for Molecular‐Orbital Studies of Organic Molecules

An extended basis set of atomic functions expressed as fixed linear combinations of Gaussian functions is presented for hydrogen and the first‐row atoms carbon to fluorine. In this set, described as 4–31 G, each inner shell is represented by a single basis function taken as a sum of four Gaussians and each valence orbital is split into inner and outer parts described by three and one Gaussian function, respectively. The expansion coefficients and Gaussian exponents are determined by minimizing the total calculated energy of the atomic ground state. This basis set is then used in single‐determinant molecular‐orbital studies of a group of small polyatomic molecules. Optimization of valence‐shell scaling factors shows that considerable rescaling of atomic functions occurs in molecules, the largest effects being observed for hydrogen and carbon. However, the range of optimum scale factors for each atom is small enough to allow the selection of a standard molecular set. The use of this standard basis gives theoretical equilibrium geometries in reasonable agreement with experiment.
Mass Action Law Conjugate Representation for General Chemical Mechanisms

Power-law rates constitute a common approximation to the general analysis of the stability properties of complex reaction networks. We point out in this paper that this form for the rates does not need to be assumed as an approximation for general rate laws. On the contrary, any functional form for a rate law can be represented exactly in terms of power laws. Moreover, we can uniquely associate to any set of kinetic equations an equivalent “conjugate” representation in terms of the well-known generalized Lotka−Volterra equations, standing for what we call per capita rates, which amounts to a great simplification in terms of the structural form of the mathematical representation of a reaction network.
A new microfluidic setup for precise control of the polymer nanoprecipitation process and lipophilic drug encapsulation

A new microfluidic setup with impact-jet micromixers was built up and applied to control the nanoprecipitation process for generating polymeric nanoparticles and encapsulating a lipophilic drug. In contrast to a conventional nanoprecipitation processes in “bulk” phase, the microfluidic approach not only allows a continuous and controlled production of nanoparticles, but can also be used to manipulate and modify the nanoparticle size and the drug loading, by fine tuning the processing parameters. We developed a micromixer-assisted setup that can efficiently produce PMMA nanospheres, with a particle size of about 100 nm, and a narrow size distribution. Moreover, this setup enables a flow rate of the polymer phase as high as 1 mL min−1, opening the possibilities of large-scale production. The obtained nanoparticles can encapsulate high levels of a lipophilic drug (ketoprofen) and release it over 4 h. Finally, the solvent and non-solvent flow rates can be used to adjust the physicochemical and encapsulating/release properties of these nanosystems, opening new possibilities for nanoparticle production by nanoprecipitation.
INFLUENCE OF LONG‐TERM RESIDUE AND FERTILIZER APPLICATIONS ON SOIL HUMIC SUBSTANCES: A STUDY BY ELECTROFOCUSING

Soil samples were taken from the plots of an experimental field that had been treated continuously for 22 years with different residue and fertilizer applications (cereal residues, cattle manure, NH4NO3). The electrofocusing (EF) technique was used to characterize the humic substances extracted from these soils with 0.5 M NaOH. The EF patterns of the organic matter extracted from the soil which had received applications of cattle manure showed many bands focused in the typical pH gradient region of the most humified compounds. The EF patterns of the organic matter extracted from both unfertilized soil and from soils amended with straw appeared to be much less complex. The addition of NH4NO3 did not affect the soil organic matter characteristics investigated with the EF technique. The results obtained show that electrofocusing is a promising technique for the characterization of humic substances and may well be particularly useful in the evaluation of differences that occur in the humic substances in soil due to residue and organic fertilizer applications.
Theory for the aggregation of proteins and copolymers

We develop mean-field lattice statistical mechanics theory for the equilibrium between denatured and aggregated states of proteins and other random copolymers of hydrophobic and polar monomers in aqueous solution. We suppose that the aggregated state is a mixture of amorphous polymer plus solvent and that the driving forces are the hydrophobic interaction, which favors aggregation, and conformational and translational entropies, which favor disaggregation. The theory predicts that the phase diagram for thermal aggregation is an asymmetric closed loop, and for denaturants (guanidinium hydrochloride of urea) it is asymmetric with an upper consolute point. The theory predicts that a copolymer in a poor solvent will expand with increasing polymer concentration because of {open_quotes}screening{close_quotes} of the solvent interactions by the other chains; the chain ultimately reaches a theta-like state in the absence of solvent. The screening concentration depends strongly on the copolymer composition. We find two striking features of these copolymer phase diagrams. First, they are extraordinarily sensitive to the copolymer composition; a change of one amino acid can substantially change the aggregation behavior. Second, relative to homopolymers, copolymers should be stable against aggregation at concentrations that are higher by many orders of magnitude. 43 refs., 13 figs.
Controllable Route to Solid and Hollow Monodisperse Carbon Nanospheres

An effective mechanism to prepare monodisperse carbon nanospheres with a regular round-ball-like shape is introduced. The route involves three steps: first, to synthesize monodisperse cross-linked polystyrene beads (CLPBs) by soap-free emulsion polymerization; second, to increase the cross-linking degree of CLPBs via Friedel−Crafts alkylation as a post-cross-linking reaction; third, to carbonize the reaction product. Both solid and hollow carbon spheres can be produced by adjusting the post-cross-linking reaction time. Fourier transform infrared spectra demonstrated the occurrence of a Friedel−Crafts alkylation reaction, and X-ray diffraction results showed that the carbon nanospheres are amorphous in structure. Typically, nitrogen adsorption/desorption measurements indicate that solid and hollow carbon nanospheres have a Brunauer−Emmett−Teller surface area as high as 498 and 451 m2/g, respectively. So it indicates that this method is novel in the field of preparation of carbon microspheres.
The Role of Skin Absorption as a Route of Exposure to Volatile Organic Compounds in Household Tap Water: A Simulated Kinetic Approach

BSORPTION OF VOLATILE ORGANIC CONTAMINANTS (VOCs) in tap water by exposure routes A other than direct ingestion, such as inhalation and dermal contact, has been recognized only recently by the risk assessment community. Transfer of volatile water contaminants to indoor air has received particular attention. (I-s) Experimental measurements of volatization of organic solutes during showering(3.4) indicate that the inhalation dosage may be as large or larger than the direct ingestion dosage. Theoretical models developed to simulate the transfer of volatile organics from water to indoor air further support those experimental measurement~. (*~~) Human exposure to volatile water contaminants during bathing, while recognized, has generally received less attention, although several recent publications on that subject may be indicative of changing attitudes. (6,7) In our earlier work(@, we have shown that the dermal route may be a significant contributor to the total exposure to VOCs in tap water and, under some circumstances, may be its major source. Our estimates were based on the absorption rates determined experimentally by Ductkiewicz and Tyras.(gJO) Implicit in our model was the assumption of steady-state absorption rate, which may not be true in a typical exposure setting of a person taking a 15 or 20 min bath. We therefore need a kinetic model for transdermal absorption of chemicals in dilute aqueous solutions. Guy, Hadgraft, and Maibach proposed two similar pharamacokinetic models(11.12) for percutaneous absorption of topically administered drugs. The models considered four linear compartments (skin surface, stratum corneum, epidermis and blood/urine, and surface, stratum corneum, epidermis/blood, and urine, respectively) and required the knowledge of several rate constants for transport between these compartments. A simplified version of the two models proposed by Guy and Hadgraft(l3). consisted of three linear compartments (epidermis, blood, and urine) and required fewer data inputs but was specifically developed to predict the plasma levels of drugs following dermal application with a specifically designed rate-controlling device.
A path-dependent constitutive model for gilding copper

A constitutive model for gilding copper is presented. The model is an extension of a successful path-dependent model developed by Goldthorpe for the deformation of fcc materials. Gilding copper is a face-centred cubic metal and its deformation behaviour is, therefore, fully dependent upon the load path taken. This path-dependent model is the first constitutive model that treats path-dependency in a physically realistic manner and gives a complete description of loading and unloading paths; it can be implemented into hydrocodes with no significant cost. The necessity for extending the model using gilding copper as an exemplar material is to include the effects of alloying and of prior processing into the model. It introduces a generic principle in which the underlying dislocation dynamics are governed by the copper. All aspects of the model are presented and explained and determination of the constants for the model from experimental data is shown. Validation of the model by comparison with mechanical tests performed under changing conditions is presented together with predictions for the same tests using the Armstrong-Zerilli model.
Velocity of Swallowed Gel Food in the Pharynx by Ultrasonic Method

超音波パルスドップラ法を用いて測定し, 咽頭部での流速スペクトルの20回以上を平均することで, ヒトの嚥下時における咽頭部を流れる食物の速度分布と粒子密度分布が得られた. 誤嚥しやすい食物と誤嚥しにくい食物の流速スペクトルには明らかな違いがあり, 超音波測定することで誤嚥する要因を考えることができ, ゲルの誤嚥の危険性・安全性を評価する指標を示すことができた. 超音波測定で定量的に示された咽頭部での最大流速と動的粘弾性との関係から, 貯蔵弾性率G' 100Pa以上, 粘性率η 2Pa・s以上のゲルでは, 咽頭部での最大流速が0. 2m/sと変わらず, 誤嚥しにくいと判断することができた. 食物の誤嚥しやすさと動的粘弾性による物性値には相関があることを明らかにし, 動的粘弾性測定により誤嚥の危険性・安全性を推測することができることが示された.
Terahertz properties of fluorinated liquid crystals

In this article, optical properties of four fluoro-substituted 4-propyl-4′-[(4-ethylphenyl)ethynyl] biphenyls and liquid crystal mixture A are presented in the terahertz (THz) range. Birefringence, refractive indices and absorption coefficients for ordinary and extraordinary ray of liquid crystals are described in the range of 0.3 to 3.0 THz. It shows that the measured parameters are dependent on the number and placement of fluorine atoms in the molecules. Measurements have been performed using time-pulsed spectroscopy.
Alternatives for Nitrogen Diagnosis for Wheat with Different Yield Potentials in the Humid Pampas of Argentina

A correct determination of nitrogen (N) fertilization thresholds in wheat that is based on objective yield produces efficient use of this nutrient. Nitrogen fertilization recommendations for traditional wheat require determination of nitrate (NO3 −)-N availability at 60 cm deep at planting time. However, this methodology is complicated, expensive, and time-consuming; thus, the determination of NO3 −-N level at a lesser depth and at a different time would be desirable. The goals of this work were to determine available N in soil thresholds for traditional and French germplasm wheats and the feasibility of diagnosing N requirements by measuring NO3 −-N at 40 cm deep, at planting or tillering times, in the southeastern Pampas. The experiments were factorial combinations of N rates and fertilization times (planting and tillering) at different sites and years during 2002–2006. Nitrogen fertilization significantly increased grain yield and protein content. French varieties presented greater grain yield (23%), lower protein content (11%), and greater yield per N unit, indicating greater N-use efficiency (NUE) than traditional varieties. A similar relationship was determined between grain yield and available N at both sampling depths. This might be explained by the strong association between NO3 −-N content at 60 and 40 cm deep at both sampling dates. Maximum yield and available N determined at 60 or 40 cm soil deep showed that thresholds were lower for tillering than for planting, regardless of the genotype (152 and 174 kg of available N, respectively). Available N thresholds for 95% of maximum yield were less at 0–40 cm deep than at 0–60 cm deep (10 and 14 kg N ha−1 for traditional and French genotypes, respectively). The results of this experiment suggest the possibility of diagnosing N requirements for wheat by measuring NO3 −-N content at 40 cm deep, instead of the usual 60 cm, for both traditional and French genotypes.
Copolymerization of 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methyl acrylate and (10‐oxo‐10‐hydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl) methyl acrylate with styrene and their thermal degradation characteristics

Two phosphorus-containing acrylates of 1-oxo-2,6,7-trioxa-1-phorsphabicyclo[2,2,2]oct-4-yl methyl acrylate and (10-oxo-10-hydro-9-oxa-10λ5-phosphaphenanthrene-10-yl) methyl acrylate were free-radical-copolymerized with styrene (St). The r1 reactivity ratio values (related to the novel acrylates) were 0.342 and 0.225, respectively, and the r2 reactivity ratio values (related to St) were 0.432 and 0.503, respectively. The thermal stability of the copolymers was tested by thermogravimetric analysis (TGA) in N2 or air, and the ignitability was tested by measurements of UL-94 vertical combustion tests and the limiting oxygen index. The results of TGA and combustion tests indicated that the effect of flame retardancy was determined by the nature of the phosphorus-containing substituent. Compared with the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide based group, the 1-oxo-2,6,7-trioxa-1-phorsphabicyclo[2,2,2]oct-4-yl methol based group could enhance the ability of char formation with an antidripping effect. It is concluded that phosphorus-containing acrylates are potential flame-retarding monomers for styrenic polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Performance of Prefilming Airblast Atomizers in Unsteady Flow Conditions

Within the context of lean premixed prevaporized combustion (LPP) which is considered as most promising technology for the next generation of low emission combustors for aero engines, combustion instabilities are a major issue. These combustion instabilities may compromise the pollutant emissions and even cause damage to the combustion chamber structure. In the literature, numerous phenomenological studies on combustion oscillation are available, but a comprehensive theory is still missing. One potential excitation mechanism is the interaction of strong air velocity fluctuations and pressure oscillations with the airblast atomizer leading to temporal fluctuations of the spray characteristics. This phenomenon was investigated experimentally at the Institute of Thermal Turbomachinery (ITS) within a parametric study. A duct with a prefilming surface was set up as an abstraction of a prefilming airblast atomizer. A mean air velocity up to 65 m/s can be reached, and periodic oscillations can be superimposed by means of a siren with a frequency up to 570 Hz. The disintegration process of the liquid fuel was studied downstream the atomizing edge of a plain airblast nozzle. Several optical diagnostics like phase resolved LDV (Laser Doppler Velocimetry) and an improved PTV technique (Particle Tracking Velocimetry) were used. The mean air velocity, the film load, the kinematic viscosity and the surface tension of the fluid as well as the pulsation frequency and amplitude of the siren were varied, and their effect on the temporal evolution of the droplet size and droplet rate was studied. It was found that the amplitude of fluctuations of the droplet size and the droplet rate is almost proportional to the air velocity fluctuations at low frequencies. At higher frequencies, however, both are nearly unaffected. In addition, the fluctuations of droplet diameter and rate increase strongly if the mean air velocity is increased. The phase shift between particle diameter, particle rate and air velocity fluctuations was found to increase at higher excitation frequencies. © 2006 ASME
New nonlinear optical chromophores exhibiting good transparency and large nonlinearity: synthesis and characterization of chromophores with stilbene and ring-locked triene as a combined conjugation bridge

Two new chromophores employing the combination of stilbene and ring-locked triene as their conjugation bridge were synthesized and found to display blue-shifted absorption and large optical nonlinearity compared with their stilbene-only, triene-only and azobenzene analogues. The two new chromophores with the combined conjugation bridge provide better optimization of the nonlinearity–transparency trade-off.
Ion-molecule chemistry of dense interstellar clouds - Nitrogen-, oxygen-, and carbon-bearing molecule abundances and isotopic ratios

Revised time-dependent models of the ion-molecule chemistry of dense interstellar clouds (Graedel, Langer, and Frerking, 1982) are used to calculate the abundances of key observational species used to interpret cloud properties and study interstellar chemistry. Consideration is given to nitrogen-, oxygen-, and carbon-bearing molecules and isotopic ratios over a hydrogen density range of 1,000-50,000/cu cm and a temperature range of 10-40 K. The results for over 15 species, including C-13 variants, are presented in tables and graphs. The results are compared to abundance observations in TMC-1 and other interstellar clouds, showing that most observed abundances can be predicted by the models. 72 references.
Flavonol glycosides from the leaves of Acacia mangium and related species

Several flavonol glycosides have been isolated from the leaves of Acacia mangium, A. auriculiformis, A. richii and A. mangium x A. auriculiformis. A. mangium was characterised by the presence of the 3-glucoside of quercetin, quercetin-3- diglucoside in addition to kaempferol-3,7-dirhamnoside and kaempferol-7,4'-digalactoside. On the other hand, A. richii contains myricetin-3-glucoside and kaempferol-3-dixyloside whereas A. auriculiformis contains isorhamnetin and quercetin-7- glucoside. These compounds have hitherto never been reported from Acacia. Abstrak. Beberapa flavonoid glikosida telah diasingkan daripada daun Acacia mangium, A. auriculiformis, A. richii dan A. mangium x A. auriculiformis. A. mangium telah dicirikan dengan kehadiran kuersetin-3-glukosida, kuersetin-3- diglukosida dan juga kaemferol-3,7-dirhamnosida dan kaemferol-7,4'-digalaktosida. A. richii sebaliknya mengandungi mirisetin-3-glukosida dan kaemferol-3-dizilosida, manakala A. auriculiformis pula mengandungi isorhamnetin dan kuersetin-7- glukosida. Sebatian-sebatian ini belum pernah lagi di laporkan daripada Acacia.
Temperature-swing gas separation with electrothermal desorption step

Abstract Results of an experimental investigation of a new method for heating adsorbent beds in the desorption step owing to Joule's heat generated inside the adsorbent particles by passing an electric current through them are presented. Desorption of a previously saturated bed and cyclic separation with the electric potential applied to a fibrous activated carbon bed was performed.
Anionic synthesis and detection of fluorescence‐labeled polymers with a terminal anhydride group

To monitor polymer–polymer coupling reactions between two different monofunctional polymers in dilute polymer blends, fluorescence-labeled anhydride-functional polystyrene (PS) and poly(methyl methacrylate) (PMMA) were prepared by conventional anionic polymerization. Sequential trapping of lithiopolystyrene by 1-(2-anthryl)-1-phenylethylene (APE) and then di-t-butyl maleate (4) provided, after pyrolysis, anhydride-functional fluorescent PS. Fluorescent PMMA anhydride (8) was synthesized with sec-butyllithium/APE as an initiator for the anionic polymerization of methyl methacrylate, trapping by 4, and pyrolysis. These polymers could be reacted with amine-functional polymers by melt blending, and the reaction progress could be monitored by gel permeation chromatography coupled with fluorescence detection. This technique not only allows monitoring of the coupling reaction with high sensitivity (ca. 100 times more sensitive than refractive index detection) but also permits selective detection because unlabeled polymers are invisible to fluorescence detection. This highly sensitive and selective detection methodology was also used to monitor the coupling reaction of 8 with PS-NH2 at a thin-film interface, which was otherwise difficult to detect by conventional methods. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2177–2185, 2000
Ordering and Melting of Block Copolymer Spherical Domains in 2 and 3 Dimensions

We observe that a 2-D single crystalline layer of spherical diblock copolymer domains templated by lateral substrate topology melts via a continuous defect generation process, similar to that predicted by Kosterlitz, Thouless, Halperin, Nelson, and Young. The layer of spheres is allowed to order (or disorder) by annealing for 72 h at a given temperature, T, that corresponds to a given χNmin, where χ is the temperature-dependent Flory−Huggins parameter and Nmin is the number of mers in the minority block. The structure of the layer is revealed by imaging the ion beam etched film using scanning force microscopy. If χNmin > 9, the film is polycrystalline and the system appears to be kinetically trapped. For 9 > χNmin > 7.4, we observe that the film is a single crystal with quasi-long-range order and few defects, as expected for the 2-D crystal. As T is increased further (χNmin is decreased), we observe that defects are generated, predominantly dislocation pairs and other dislocation clusters with no long-ran.
Flow behavior of foam: A porous micromodel study

The flow behavior of foam in porous micromodels has been studied visually by use of etched silicon wafers. Air was injected into homogenous and heterogeneous porous media previously filled with an aqueous surfactant solution. The flow characteristics and the mobility of the injected air were determined under different conditions of pore dimensions, air injection rates, and surfactant concentrations. In the experiments, air was found to be propagated by displacement of lamellae in long bubbles flowing and extending across several pore lengths, while the liquid flowed through the network of films. Propagation of foam bubbles formed at pore constrictions by snap-off was dominant in the heterogeneous model. Liquid and/or gas was trapped in some pores. The mechanisms observed depended on pore structure and surfactant concentration. A considerable reduction of effective air mobility was observed in the presence of foam. Mobility reduction depended on flow mechanisms.