Miracle-dz/UniFAR-FTUs huggingface dataset:
Oxidation Dynamics of Epitaxial Rubrene Ultrathin Films

Great effort is being devoted to the fabrication of electronic devices based on rubrene thin films, because its outstanding charge transport properties make it one of the most promising organic semiconducting materials. Nonetheless, charge transport is strongly affected by the degree of crystallinity and degradation by photo-oxidation of rubrene. In the present work, in order to understand the dynamics of oxidation of rubrene when in the crystalline thin-film form, a combination of scanning probe techniques, such as Kelvin probe, phase contrast, and surface morphology atomic force microscopy, is used to study the oxidation process under ambient conditions of rubrene crystalline ultrathin films grown by organic molecular beam epitaxy on tetracene substrates. These films have a thickness of one or two molecular layers and consist of separated, island-like, epitaxial domains, whose orientation is determined by organic epitaxy. Theoretical calculations of the rubrene peroxide molecular dipole and structural d.
Heating mechanism in direct current superposed single-frequency and dual-frequency capacitively coupled plasmas

In this work particle-in-cell/Monte Carlo collision simulations are performed to study the heating mechanism and plasma characteristics in direct current (dc) superposed radio-frequency (RF) capacitively coupled plasmas, operated both in single-frequency (SF) and dual-frequency (DF) regimes. An RF (60/2 MHz) source is applied on the bottom electrode to sustain the discharge, and a dc source is fixed on the top electrode. The heating mechanism appears to be very different in dc superposed SF and DF discharges. When only a single source of 60 MHz is applied, the plasma bulk region is reduced by the dc source, thus the ionization rate and hence the electron density decrease with rising dc voltage. However, when a DF source of 60 and 2 MHz is applied, the electron density can increase upon addition of a dc voltage, depending on the gap length and applied dc voltage. This is explained from the spatiotemporal ionization rates in the DF discharge. In fact, a completely different behavior is observed for the ionization rate in the two half-periods of the LF source. In the first LF half-period, the situation resembles the dc superposed SF discharge, and the reduced plasma bulk region due to the negative dc bias results in a very small effective discharge area and a low ionization rate. On the other hand, in the second half-period, the negative dc bias is to some extent counteracted by the LF voltage, and the sheath close to the dc electrode becomes particularly thin. Consequently, the amplitude of the high-frequency sheath oscillations at the top electrode is largely enhanced, while the LF sheath at the bottom electrode is in its expanding phase and can thus well confine the high-energy electrons. Therefore, the ionization rate increases considerably in this second LF half-period. Furthermore, in addition to the comparison between SF and DF discharges and the effect of gap length and dc voltage, the effect of secondary electrons is examined.
Cationic copolymerization of cycloaliphatic epoxy resin with a spirobislactone with lanthanum triflate as initiator: I. Characterization and shrinkage

3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (ECH) was cured with different proportions of 1,6-dioxaspiro [4,4]nonane-2,7-dione (s(γ-BL)) using lanthanum triflate as a catalyst. The shrinkage undergone during curing was monitored by means of thermomechanical analysis (TMA) in isothermal experiments. Fourier transform infrared spectroscopy in attenuated-total-reflection mode (FTIR/ATR) was used to study the evolution of lactone, epoxide, and intermediate spiroorthoester (SOE) groups to identify the different reactions that take place during the curing process. DSC was used to study the thermal characteristics of the curing process and to assess the glass-transition temperature (Tg) of the cured material. The dynamic mechanical properties of the cured material were determined based on the data obtained by DMTA. An increase in the proportion of s(γ-BL) led to a decrease in the gelation time and the shrinkage after gelation. By combining the data obtained by TMA and FTIR/ATR, it was also possible to identify the reactive processes responsible for the shrinkage. It was observed that an increase in the proportion of s(γ-BL) also increases the speed of the curing process and modifies the structure of the material, thus giving rise to more flexible materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3421–3432, 2005
Kinetics of the ClO Self-Reaction and 210 nm Absorption Cross Section of the ClO Dimer

The kinetics of the dimerization of ClO radicals, ClO + ClO + M → Cl2O2 + M (1a), and the 210 nm absorption cross sections of the ClO dimer have been studied using the technique of flash photolysis with UV absorption spectroscopy, over the temperature range 183−245 K and pressure range 25−700 Torr. ClO radicals were generated following the photolysis of Cl2/Cl2O/N2 mixtures and were quantified via their differential absorption between the peak of the (12,0) band of the (A ← X) transition at 275.2 nm and the adjacent minimum to higher wavelengths, while Cl2O2 formation was simultaneously monitored at 210 nm. ClO differential absorption cross sections were measured under identical conditions to the kinetic experiments by four separate calibration schemes. The rate coefficient measured at the lower temperatures studied (T < 200 K) was found to be up to 40% faster than extrapolation of previous results would suggest, with the limiting low- and high-pressure rate coefficients for reaction 1 in nitrogen determ.
Chemical constituents from Clerodendrum bungei and their cytotoxic activities.

A new phenylethanoid glycoside, two new cyclohexylethanoids, one new phenolic glycoside, and a new farnesane-type sesquiterpenoid, namely 2-phenylethyl 3-O-(6-deoxy-a-l-mannopyranosyl)-b-d- glucopyranoside (1), 6''-O-((E)-caffeoyl) rengyoside B (2), clerodenone A (3), 2-({6-O-((4-hydroxy-3- methoxyphenyl)carbonyl)-b-d-glucopyranosyl}oxy)-2-methylbutanoic acid (4), 2-{(2S,5R)-5-((1E)-4- hydroxy-4-methylhexa-1,5-dien-1-yl)-5-methyltetrahydrofuran-2-yl}propan-2-yl b-d-glucopyranoside (5), together with 16 known compounds, were isolated from the roots of Clerodendrum bungei. All structures were elucidated by spectroscopic methods. The new compounds showed modest in vitro inhibition of the proliferation of the HeLa human cervical carcinoma cell line (CCL-2), with IC50 values in the range of 3.5 - 8.7 mm, adriamycin being used as positive control, with an IC50 value of 0.026 � 0.001 mm. Introduction. - The genus Clerodendrum (Verbenaceae) contains more than 30 species distributed in China, some of which have been used as Traditional Chinese Medicine (TCM), such as Clerodendrum indicum for treating malaria and rheumatism (1), Clerodendrum inerme possessing antimicrobial and protecting cardiovascular system activity (2), and Clerodendrum calamitosum for treating calculus in bladder, kidney, and gall as a diuretic (3). The characteristic chemical constituents of this genus are phenylpropanoid and phenylethanoid glycosides, flavonoids, diterpenoids, and iridoids (4). Clerodendrum bungei Steud. is a small shrub mainly distributed in south of China. Local inhabitants have used its stems and leaves as a folk medicine to be a detoxifying and detumescent drug (5) for a long time. Preparations of the leaves and branches of C. bungei have been used in folk medicine to treat boils, hemorrhoids, eczema, and hypertension, and the roots are used to alleviate rheumatism, beriberi, hypertension, and prolapse of the uterus (6). Several types of constituents including diterpenoids (6) (7), phenylethanoid glycosides (8), steroids and triterpenoids (9) (10) have been identified from this plant. In our continuing chemical studies and screening of bioactive components from Chinese medicinal plants (11), five new compounds along with sixteen known ones were isolated from the aqueous acetone extract of the roots of C. bungei, and their in vitro cytotoxic activities against the HeLa human cervical carcinoma cell line (CCL-2) were investigated. This article reports on the structural elucidation and cytotoxic activity of new compounds 1 - 5. Results and Discussion. - Structure Elucidation. Compound 1 was obtained as a yellow amorphous powder, with the molecular formula C20H30O10 determined from the HR-ESI-MS (m/z 453.1721 ((M þ Na) þ , calc. 453.1737)). The H-atom and H-atom-
Charge transfer associated with the physical process of hardness equalization and the chemical event of the molecule formation and the dipole moments

In this article, we have basically launched a search whether the dipole charge and dipole moment of heteronuclear diatomics can be justifiably evaluated in terms of charge transfer kernel using the hardness equalization principle as basis. We have derived a formula for computing dipole charge (q) on the basis of hardness equalization principle as q = aδ + b, where “a” and “b” are the constants and “δ” is the kernel of charge transfer from less hard atom to more hard atom during the rearrangement of charge on molecule formation. We have computed the dipole charges and dipole moments of as many as six different sets of compounds of widely diverse physicochemical behavior in terms of the algorithm derived in the present work. The computed dipole charge nicely reveals the known chemicophysical behavior of such compounds as are brought under the study. A comparative study of the nature of variation of theoretically evaluated and experimentally determined dipole moments reveals that there is an excellent agreement between the two sets of dipole data. Thus, the new algorithm derived for the calculation of the dipole charge using the hardness equalization principle as a basis is efficacious in computing the distribution and rearrangement of charge associated with the chemical event of molecule formation. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Cassava starch processing at small scale in North Vietnam

In Northern Vietnam, small-scale cassava starch processing is conducted in densely populated craft villages, where processors face difficulties to expand their activities. Three different processing systems were studied among a cluster of three communes in the Red River Delta, producing up to 430 t of starch (at 55% dry matter) per day. The first system, type A, is a cylindrical rasper and a manual sieve, the second, type B, is a cylindrical rasper and stirring-filtering machine and the third, type C, used equipment for both the rasping and filtering stages. Moisture, starch, crude fibers and ash content analysis were carried out on samples collected from the A-B-C manufacturing processes to establish the mass balance of starch. Production capacity, water consumption, electrical requirements and capital-labor costs per tonne of starch (12% moisture) were also reported. A-B-C manufacturing processes enabled 75% recovery of the starch present in fresh roots. No significant change was observed in the composition of starch. Upgrading from system A to B and subsequently to C resulted in an increase in the extraction capacities (up to 0.9 t of peeled roots per hour), the extraction efficiencies during the extraction stage (up to 93%), and an increase in the water consumption and electrical power (up to 21 m3 and 55 kWh per tonne of starch, respectively). The highest amount of total solids carried in the waste-water was obtained with type C (up to 17% of the dry weight of fresh roots, compared to 10% and 13% for type A and B, respectively). This may lead to a higher chemical oxygen demand (COD) and biological oxygen demand (BOD) in waste-water, which can result in more polluted waste-water than compared with the type A and B technologies. Upgrading the rasping-extraction technologies also resulted in higher profits and reduction of labor per tonne of starch (up to 18 US$ and 26 man-hours respectively). The diagnosis proposed in this study can be applied in different contexts to recommend technological options by considering space, energy and capital-labor availabilities. (Resume d'auteur)
Formation of soils with contrasting textures by translocation of clays rather than ferrolysis in flooded rice fields in Northeast Thailand

This paper describes the conditions for dispersion and flocculation of clays, and the impact of this process on soils of contrasting textures cropped with rice. Clay seems to be translocated down the profiles and along a topographic sequence. The clays are mixed kaolinite–smectite. The cation exchange capacity of these clays exceeds 20 cmolc kg−1. Both the proportion of smectite and clay content increase with increasing depth and from the top to the lower part of the sequence. The pH ranges from 5 to 8. The aluminium oxide content is small. The soil solutions collected during the rainy season were analysed for Fe2+ and major cations. We calculated the sodium adsorption ratios (SAR) taking into account Fe2+ and compared them with the critical coagulation concentration (CCC) found in a previous study. The Fe2+ contributed to a decrease in the SAR of cropped soils. The comparison between SAR, total electrolyte concentrations and CCC values showed that the dispersible clays are likely (i) to disperse in the abandoned and non‐saline fields, (ii) to flocculate in the saline and uncropped soils as a result of the large salt content and in the cropped soils because of either large salt or Fe2+ content, and (iii) to disperse in the flood water and at the surfaces of abandoned fields under rain. No evidence for ferrolysis was found. The observed contrasting textures and clay mineralogy can be explained by clay translocation controlled by salinity and rice farming.
The impact of ZIF-8 particle size and heat treatment on CO2/CH4 separation using asymmetric mixed matrix membrane

In this study, zeolitic imidazole framework 8 (ZIF-8) particles of different sizes were synthesized in aqueous media by varying the concentration of the base-type additive, triethylamine (TEA). ZIF-8 with particle sizes of ∼134 nm and ∼288 nm with surface areas of 418.44 m2 g−1 and 491.54 m2 g−1 were obtained without altering the crystalline structure. Synthesized ZIF-8 was further heat treated at 100 °C for a minimum of 12 hours, which led to an enhancement of its phase crystallinity and a surface area of 981.1 m2 g−1. Mixed matrix membranes (MMMs) were prepared via the dry–wet phase inversion method by dispersing as-synthesized ZIF-8s, heat-treated ZIF-8s and commercial ZIF-8 (∼493 nm) into a polysulfone (PSf) matrix. The thermal stability and mechanical strength of the membranes showed significant improvement after the incorporation of ZIF-8s. The MMMs were further subjected to the permeation experiments of CO2 and CH4. Although the majority of MMMs showed less selectivity than the neat PSf membrane, the incorporation of heat-treated ZIF-8 of the smallest size, exhibited CO2/CH4 selectivity of 28.5, which is significantly higher than the 19.43 obtained for the neat PSf membrane. Therefore, different ZIF-8 treatment protocols and particle sizes affect the MMMs performance significantly.
RECLAMATION OF SOILS CONTAMINATED BY SODIUM CHLORIDE

Soil samples contaminated in the laboratory with a NaCl solution were leached with water after various amendments had been added. With no amendments added, percolation rates were reduced more on a light-textured Dark Brown Chernozemic A than on a medium-textured Black Chernozemic A. Undisturbed B horizon cores showed a smaller decrease in percolation rate than the A horizons, but natural gypsum or carbonates were of no benefit in maintaining percolation through the unamended contaminated subsoils. Percolation generally increased as more Ca-amendment was added to the contaminated A horizons, but rate of (surface-applied) amendment had no effect on the percolation through the B horizon cores. Gypsum mixed into the contaminated soil was much more effective than gypsum applied on the surface; adding NH4NO3 to the gypsum had no effect. The efficiency of incorporated amendments decreased in the order: gypsum > MgSO4 > Ca(NO3)2. Surface-applied Ca(NO3)2 was a better amendment than mixed-in Ca(NO3)2. Caching loss.
Comparative study of GaN mesa etch characteristics in Cl2 based inductively coupled plasma with Ar and BCl3 as additive gases

GaN thin film etching is investigated and compared for mesa formation in inductively coupled plasma (ICP) of Cl2 with Ar and BCl3 gas additives using photoresist mask. Etch characteristics are studied as a function of ICP process parameters, viz., ICP power, radio frequency (RF) power, and chamber pressure at fixed total flow rate. The etch rate at each ICP/RF power is 0.1–0.2 μm/min higher for Cl2/Ar mixture mainly due to higher Cl dissociation efficiency of Ar additive that readily provides Cl ion/radical for reaction in comparison to Cl2/BCl3 mixture. Cl2/Ar mixture also leads to better photoresist mask selectivity. The etch-induced roughness is investigated using atomic force microscopy. Cl2/Ar etching has resulted in lower root-mean-square roughness of GaN etched surface in comparison to Cl2/BCl3 etching due to increased Ar ion energy and flux with ICP/RF power that enhances the sputter removal of etch product. The GaN surface damage after etching is also evaluated using room temperature photolumines.
Essential Oil Content and Composition in Tanacetum vulgare L. Herbs Growing Wild in Estonia

Abstract Variations in the essential oil content and composition in aerial parts of two tansy samples from different districts of Estonia were determined using hydrodistillation, GC and GC-MS techniques. The yields of the two oil samples were 0.4 and 0.5 % (w/w). Total 83 compounds identified in both the oils made up 98.4 % of each oil. The most important quantitative components in tansy oil from Harju district were trans-chrysanthenone (41.4 %), 1,8-cineole (9.6 %), β-pinene (6.5 %), α-pinene (5.0 %) and 6-camphenone (4.6 %). In the oil from Tartu district, β-thujone (47.2 %) and trans-chrysanthenyl acetate (30.7 %) predominated. Thus analyses results in assigning the Tanacetum vulgare of Harju and Tartu district as trans-chrysanthenone and β-thujone-trans-chrysanthenyl acetate chemotypes. For the first time, the β-thujone-trans-chrysanthenyl acetate chemotype was determined.
A Nonempirical Method Using LC/MS for Determination of the Absolute Configuration of Constituent Amino Acids in a Peptide: Elucidation of Limitations of Marfey's Method and of Its Separation Mechanism

As the first step in establishing our proposed method, the advanced Marfey's method, which is planned for the simultaneous determination of the absolute configuration of amino acids in a peptide, we applied Marfey's method to commercially available amino acids, and the separation behavior was examined in detail. Although good resolution of the diastereomeric pair of an individual amino acid was obtained for all amino acids tested and the applicability of the method was confirmed, the (1-fluoro-2,4-dinitrophenyl)-5-l-alaninamide (FDAA) derivative of the l-amino acid was not always eluted prior to its corresponding d-amino acid derivative. Because this proposed method relies on the elution order of a derivatized amino acid with FDAA to determine its absolute configuration, its separation mechanism was carefully investigated using UV and NMR spectral techniques. The results suggested that the resulting conformations of the l- and d-amino acid derivatives are stable and that the resolution between the l- and .
Time dependence of NO/sub x/ removal rate by a corona radical shower system

In this paper, the effects of flow rate of treatment gas and additional gas on the corona current-voltage characteristics and NO/sub x/ removal characteristics, and the operational time dependence of the corona characteristics and NO/sub x/ removal characteristics are investigated experimentally in a corona radical shower system. The corona current-voltage characteristics have two modes which have a significant influence on NO/sub x/ removal characteristics. The threshold value of the gas flow rate ratio of treatment gas to additional gas is about 8. The hysteresis of corona current-voltage characteristics is observed in this system. For longer operational time, corona current and NO/sub x/ removal rate significantly changes with time. When the operation of the apparatus starts at relatively low applied voltage, the corona current under constant applied voltage increases with time. It takes a maximum value at an operational time and then decreasing with time, finally settles down to a constant value. At this condition, high NO/sub x/ removal rate NO/sub x/ removal efficiency can be achieved. <<ETX>>
Theory of Particle Combustion at High Pressures

Conventional theories of particle combust ion become inaccurate when t h e gas pressure rises, and are complete ly useless above t h e critical pressure. The paper discusses the transient effects, neglected in conventional theories, which dominate the burning process at h igh pressures. A quanti tat ive theory is presented, valid for these condit ions , of the t i m e variations of flame radius, burning rate and combust ion efficiency.
Validation of a Method of Determination of Apparent Diffusivity Versus Composition in Solids

Abstract A method is presented for computing the values of apparent diffusivity in solids with respect to the concentration of the diffusing substance (water or sodium chloride). This method does not require any assumption upon the mathematical relationship between diffusivity and concentration. It can be applied to experimental measurements of local concentration versus position within the solid (profiles) with relatively few measurements (circa 10) and a mathematical smoothing of the experimental data by using an artificial neural network model. The method was first validated on simulated data obtained by using a constant diffusivity value and on experimental profiles when the relation between diffusivity and concentration was given. It was then applied to original experimental moisture profiles obtained by putting gelatin gels with different initial moisture contents into contact for up to 14 days. The method was also successfully applied to five sets of experimental moisture and sodium chloride profiles taken from the literature and obtained from different food products. Apparent diffusivities calculated by our method were found in agreement with those obtained by authors using different numerical methods to compute the diffusivity values.
Study of Unsteady‐State Operation of Methanation by Modeling and Simulation

Methanation of CO under unsteady-state operation conditions was studied systematically based on a simplified mathematical model for an integral reactor using steady-state kinetics available in the literature. The inlet composition of CO and H2 was changed stepwise and the step response of the system was monitored in order to study the dynamic behavior of the reactor. Furthermore, periodic changes were applied with different cycling times. It was observed that the time average reaction rate could not be improved by cycling the feed composition. Moreover, the reactor appears to be self-stabilizing, since the amplitude at the outlet is reduced, leading to a steady state for high cycling frequencies. The results allow conclusions on principles to design a methanation reactor for unsteady-state operation. However, it also becomes obvious that unsteady-state kinetics is mandatory in order to describe the experimental results obtained under dynamic conditions.