Miracle-dz/UniFAR-FTUs huggingface dataset:
Effects of porphyrin core saddling, meso-phenyl twisting, and counterions on the optical properties of meso-tetraphenylporphyrin diacids: The [H4TPP](X)2 (X = F, Cl, Br, I) series as a case study

The ground- and excited-state properties of a series of meso-tetraphenylporphyrin (H2TPP) diacids, [H4TPP](X)2 (X = F, Cl, Br, I), ad hoc synthesized and characterized by 1H NMR, RLS, and UV−vis spectroscopies, have been studied theoretically using density functional theory (DFT) and time-dependent density functional theory (TDDFT). Several conformations corresponding to different deformations of the porphyrin core have been explored. The nearly degenerate purely saddled (sad) and hybrid (saddled with a small superimposed ruffling: sadruf) conformations are the preferred “gas phase” conformations. The type and degree of distortion of the macrocycle and the orientation of the phenyl rings compare well to X-ray data available for H2TPP diacids. Two electronic structure features are key to an understanding of the optical and photophysical properties. (1) Strong interaction of the π-system of the phenyls with the π-system of the porphyrin leads to an upshift of the G-a2u (G = Gouterman) orbital and, hence, t.
Phase Transitions and Ion Conductivity in NASICON-Type Compounds Li1±XZr2-XMX(PO4)3, M = Ta, Nb, Y, Sc, In

Ionic conductivity and phase transitions of lithium-zirconium phosphates, Li1±XZr2- XMX(PO4)3 (M = Ta, Nb, Y, Sc, In), with NASICON structure were studied using X-ray powder diffraction, calorimetry, 31P and 7Li NMR and impedance spectroscopy. Triclinic-rhombohedral phase transition in these materials occurs in a wide temperature range at coexistence of both phases. Unusual change of LiZr2(PO4)3 lattice parameters with temperature increase was found. During heating of this compound parameter “a” significantly decreases.
Biogeochemistry of Methane Exchange between Natural Wetlands and the Atmosphere

This review examines the interactions among physical, chemical, and biological factors responsible for methane (CH4) emission from natural wetlands. Methane is a chemically and radiatively important atmospheric trace gas. Emission from wetlands is a significant component of the atmospheric CH4 budget, releasing 145 Tg CH4 annually to the atmosphere, or about 25% of total emissions from all anthropogenic and natural sources. Wetlands are characterized by a subsurface, anaerobic zone of CH4 production by methanogenic bacteria and an surficial, aerobic zone of CH4 oxidation by methanotrophic bacteria. Wetlands transfer CH4 to the atmosphere by diffusion, ebullition, and by transport through arenchymous vascular plants. However, about 20 to 40% of the CH4 produced in anaerobic wetland soils is oxidized in the rhizosphere and in surficial oxic layers during diffusive transport to the soil surface. Rates of CH4 emission in wetlands are commonly 100 mg m-2 day-1, and represent the net effect of production and co.
Atomic-Scale Structures of Top and Bottom Heterointerfaces in GaAs–AlxGa1-xAs (x=0.2-1) Quantum Wells Prepared by Molecular Beam Epitaxy with Growth Interruption

We have studied microscopic structures of two different interfaces in MBE-grown GaAs–AlxGa1-xAs quantum wells (QWs), and effects of growth interruption on the interface roughness. For QWs with x>0.5, the effective roughness of top (AlGaAs-on-GaAs) interfaces is drastically reduced down to less than 0.2 atomic layer by the growth interruption, whereas bottom (GaAs-on-AlGaAs) interfaces are unaffected and act as pseudo-smooth interfaces even without the interruption. However, for QWs with x<0.3, bottom interfaces are similar to top interfaces, and can be smoothed by the growth interruption. Microscopic models of various heterointerfaces are presented.
Role of climate feedback on methane and ozone studied with a Coupled Ocean‐Atmosphere‐Chemistry Model

We present results from two experiments carried out with a coupled ocean‐atmosphere‐tropospheric chemistry model run continously over the period 1990 to 2100. In the control experiment, climate is unforced, but emissions of trace gases to the chemical model increase in line with an illustrative scenario for future trace gas emissions with medium high growth. In the climate change experiment trace gas emissions are identical to the control, but climate is also forced using greenhouse gas concentrations and SO2 emissions from the same scenario. Global average methane in the climate change experiment increased from 1670 ppbv in 1990 to 3230 ppbv by 2100, compared to 3650 ppbv by 2100 in the control. The methane increase in the control experiment is therefore 27% more than in the control. This difference is due to both temperature and OH changes which increase the rate of methane oxidation and act in the opposite direction to the negative feedback of methane on itself through OH. Mid‐latitude northern hemisphere ozone concentrations in July for the mid‐troposphere rose from 39 ppbv in 1990s to 64 ppbv in the 2090s in the control experiment and to 49 ppbv in the climate change experiment. The direct role of climate change is therefore predicted to be a negative feedback on the radiative forcing from the change to tropospheric ozone and methane concentrations.
Recent Advances in Biological Sensors Based on Electrogenerated Polymers: A Review

Abstract This review describes some new approaches of biomolecule immobilization and transduction of biological processes in the field of biosensors based on electrogenerated polymers. These recent advances were classified according to the nature of the conventional immobilization procedure involved, namely adsorption onto electropolymerized films, entrapment during the electropolymerization process, covalent binding on electrogenerated polymers, and anchoring by affinity interactions between biomolecules and polymers.
Dissolution Behaviour and the Solution Property of Cellulose in NaOH/Urea/Thiourea Aqueous Solvent

Cellulose swelling and dissolving, rheological properties, crystallinity, gel Abstract. Untreated cellulose was directly and quickly dissolved in NaOH/thiourea/urea aqueous solvent at a 9/3/5/83 composition and pre-cooled at (-10 to +2)°C, and at a high shear force with 3500rpm agitating speed. The dissolving process was investigated by polarization microscope, XRD and rheometer. The result revealed that cellulose crystal forms was changed from cellulose I to cellulose II after dissolving and the crystallinity decreased. Moreover, the gel forming of cellulose has an obvious relationship with cellulose concentration and it’s easy to form gel when the cellulose concentration was above 8wt%.
Structure–performance relations of molybdenum- and tungsten carbide catalysts for deoxygenation

This work demonstrates for the first time that carbide particle size is a critical factor for the activity and stability of carbon supported tungsten- and molybdenum carbide catalysts in (hydro-)deoxygenation reactions. The stability of the catalyst was shown to increase for larger particles due to the improved resistance of the metal carbide phase against full oxidation to crystalline metal oxides under reaction conditions. In addition to the improved catalyst stability, supported molybdenum carbides were found to more than double their weight-based catalytic activity upon increasing carbide particle size from 2 to 10 nanometers. The strongly improved (de-)hydrogenation activity of these larger carbide particles also facilitated a new deoxygenation pathway for fatty acids, in which an initial hydrogenation to fatty-aldehyde is combined with a decarbonylation step. This is the first time in which this deoxygenation pathway is observed over supported tungsten- or molybdenum carbide catalysts.
Identification of the Chirality and Polarity of Intermetallic Compounds with the Point Groups of 23, 432, 422, and 321 by Electron Diffraction

A CBED (convergent-beam electron diffraction) method proposed by the present authors for chiral identification of enantiomorphic crystals has been successfully applied to intermetallic compounds with the point groups of 23, 422, 432 and 321. The intensity asymmetry of ZOLZ and/or FOLZ reflections of the Bijvoet pairs is easily recognized in CBED patterns with the incidence along the appropriate zone-axis orientations for each of the two members of the enantiomorphic pair and the intensity asymmetry with respect to the symmetry line is reversed upon changing the space group (handedness) from one to the other. Thus, the generality of the proposed method in identifying the chirality for all crystallographycally possible enantiomorphic crystals is verified.
Plankton 3D tracking: the importance of camera calibration in stereo computer vision systems

Computer vision applications are very useful to study animal movements, but due to their intrinsic complexity they are challenging to design, implement, and use properly. We here describe a calibration procedure for a laboratory stereo vision system for tracking zooplankton in three dimensions (3D). We demonstrate the crucial importance of using a correct calibration for proper interpretation of animal swimming tracks. We also address the effect of the air‐water shift phase in the calibration procedure. Actually, not performing a proper calibration caused an average positional error of more than 25 body‐lengths in the investigated animal Daphnia magna. Furthermore, we evaluate the different outcomes of using 2D and 3D tracks obtained with a calibrated stereo vision system and show that although 2D tracking might be sufficient in some cases, the method was in our study unable to give information of swimming path geometry and underestimated the speed by 25%. Finally, we discuss consequences for biologically relevant questions when an incorrect methodology is used and strongly recommend that future studies provide detailed descriptions of the framework used for calibration to allow for comparisons between different studies.
Backward Euler and other methods for simulating molecular fluids

Two implementations of the backward Euler method for simulating molecular fluids are compared with Brownian dynamics and molecular dynamics simulations of a single diatomic molecule, liquid argon, a single butane molecule, and liquid butane. By comparison with standard molecular dynamics results, backward Euler simulations give different thermodynamic properties for liquids; predict liquid structures which are too solidlike; and incorrectly represent dynamical relaxation processes. The backward Euler methods allows longer time steps to be used in simulations at the cost of an energy minimization at every time step. Even when time steps more than 20 times larger than that required for energy and momentum conservation are used, neither implementation of the backward Euler algorithm is more accurate than standard molecular dynamics calculations with the same time step. We conclude that the new methods offer no computational advantages over more usual methods for simulating molecular fluids and that they ofte.
Morphology and Proton Conductivity of Composite Membranes Based on PWA and PPEK

A series of HPA-containing Poly(phthalazinone ether ketone) (PPEK) membranes was prepared and their microstructure and conductivities were studied in this work. The results showed the composite membrane had no proton conducting ability with PWA content less than 75%, while the conductivity for the PWA/(PEEK-PVP) membranes with 35% of PWA was higher than 4×10-4 S/cm. Proton conductivities up to 4.86×10-3 S/cm have been measured at temperatures up to at 140°Cand 100% RH for PWA/(PEEK-PVP) membranes with 35% of PWA and 70% PVP. The relationship of conductivity and the morphology of the PPEK/PWA membranes showed that the PWA particle dispersion is the key parameters.
Chemical constituents of the essential oil from leaves of Psidium cattleianum var. cattleianum

The essential oil obtained by hydrodistillation of dried leaves of Psidium cattleianum var. cattleianum was analysed by gas chromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS). A total of seventy six compounds, representing 97.5% of the oil were identified. The major constituents of the essential oil were caryophyllene oxide (29.56%), alloaromadendrene oxide-(1) (6.82%), 12-oxabicyclo [9.1. 0] dodeca-3,7-diene (5.85%) and 1H-cycloprop[e]azulene (3.49%). High concentration of caryophyllene oxide in the oil suggests its usefulness as natural preservative in food industry. The terpenic and ester compounds could contribute to the aroma of P. cattleianum var. cattleianum .
WHOLE-PLANT NET CO2 EXCHANGE OF RASPBERRY AS INFLUENCED BY AIR AND ROOT-ZONE TEMPERATURE, CO2 CONCENTRATION, IRRADIATION, AND HUMIDITY

The influence of irradiance, CO 2 , and temperature on whole-plant net CO 2 exchange rate (NCER) of Rubus idaeus L. 'Heritage' micropropagated raspberries was examined. Within the set of environmental conditions examined, irradiation was the most important factor, accounting for 58% of the whole-plant irradiance/CO 2 concentration/ temperature NCER model variation, followed by CO 2 concentration (28%) and temperature (2.5%). Net photosynthesis (Pn) required irradiance levels >600 μmol·m -2 ·s -1 PPF for saturation, greatly increased under CO 2 enrichment (up to 1500 μL·L -1 ), and was optimum at a whole-plant temperature of 20 °C. Temperature effects were partitioned in an experiment using varying air and root-zone temperatures (15, 20, 25, 30, and 35 °C) under saturated light and ambient CO 2 levels (350 μL·L -1 ). Air and root-zone temperature influenced Pn, with maximum rates occurring at an air × root-zone temperature of 17/25 °C. The contribution of air and root-zone temperature to the NCER model varied, with air and root-zone temperature contributing 75% and 24%, respectively, to the total model variation ( R2 = 0.96). Shoot dark respiration increased with air and root-zone temperature, and root respiration rates depended on air and root-zone temperature and shoot assimilation rate. Humidity also influenced Pn with a saturated vapor pressure deficit threshold >0.25 kPa resulting in a Pn decrease. Quantifying the physiological response of raspberries to these environmental parameters provides further support to recent findings that cool shoot/warm root conditions are optimum for raspberry plant growth.
HRGC/FID/NPD and HRGGC/MSD study of Colombian ylang‐ylang (Cananga odorata) oils obtained by different extraction techniques

Steam distillation (SD), simultaneous distillation-solvent extraction (SDE), and supercritical (CO2) extraction (SFE) were used to isolate volatile secondary metabolites from fresh, totally mature flowers of Colombian ylang-ylang (Cananga odorata). The various extracts were analyzed by capillary chromatography (DB-1, DBWAX, 60 m columns) using FID, NPD or MSD (EI, 70 eV). Kovats indexes, mass spectra, or standard substances were employed for compound identification. 51, 70, and 73 compounds at concentrations above 100 ppb were detected in the SD, SDE, and SFE extracts, respectively. The main constituents of these extracts were linalool (20.7, 28.0, and 16.5%), germacrene-D (10.1, 3.1, and 20.3%) benzyl benzoate (14.1, 2.9, and 3.9%), benzyl acetate (9.6, 17.0, and 6.2%), caryophyllene (3.1, 2.9, and 3.9%), and p-methylanisole (6.8, 6.1, and 2.7%). 85% of the composition of SDE extracts was represented by oxygenated compounds. Heavy hydrocarbons (Cn >20) and fatty acids were found only in the SFE extracts, which also had a higher content of nitrogenated compounds (phenylacetonitrile, 4-methylbenzaldoxime, indole, 2-phenyl-nitroethane, and methyl anthranilate) and sesquiterpenes (43% vs 19.5% in SD and 8.1% in SDE) and 1.5 – 2 times lower concentration of monoterpenes and light oxygenated compounds than the SD (49.7%) and SDE (64.5%) extracts.
Doping of ZnO by group-IB elements

The authors present their first-principles calculations of doping effects in ZnO with group-IB elements such as Cu, Ag, and Au. The calculated transition energies e(0∕−) for substitutional Cu, Ag, and Au are 0.7, 0.4, and 0.5eV, respectively. The calculated formation energies are very low for these group-IB elements on the substitutional sites, but rather high at the interstitial sites under oxygen-rich growth conditions. Under the conditions, the formation of major hole-killer defects, such as oxygen vacancies and Zn interstitial, are suppressed. Thus, Ag may be a good candidate for producing p-type ZnO.
Hands shape recognition using moment invariant for the Korean sign language recognition

This paper reports a recognition system of Korean sign language. The sign language is a visual language usually used by the deaf and dumb. The user expresses the meaning using the hands' motion, position and shape. This paper reports recognizing chiromancy which expresses the meaning by the hands' shape. Using the visual information, the system is able to recognize the chiromancy. The system uses spatial feature of an object in order to recognize hands' shape because the chiromancy communicates the meaning by a spatial arrangement of the shape. For analyzing the spatial feature, the moment invariants are adopted. The moment invariance is the method of the analyzing the physical property. The moment of invariance is able to recognize the meaning of transformed the translation, the scale change and the rotation of hand's shape. The alphabets in the chiromancy of the Korean sign language consist of 14 consonants and 16 vowels. The chiromancy is able to distinguish the meaning according to the fingers' shape and posture. The problem often arises even when the hand has the identical shape, because the meaning changes according to the posture of hand. Therefore the principal axis is used in order to distinguish the posture to understand the meaning. Moment invariance contains abundance of information about the hands' shape. The lower order moment is not sensitive to the shape changes. Therefore, we divide the region into quadrants by the principal axes. Normalized moments of each quadrant region are used to determine the hands' shape. In the experiment, hand shapes used in Korean sign language are determined 97% in exactness.
Coarse-grained hybrid simulation of liposomes

We developed a new hybrid model for efficient modeling of complete vesicles with molecular detail. Combining elements of Brownian dynamics (BD) and dynamic density functional theory (DDFT), we reduce the computational load of an existing coarse grained particle-based dissipative particle dynamics (DPD) model by representing the solvent as a continuum variable or a field, in a consistent manner. Both particle and field representations are spatially unrestricted and there is no need to treat boundaries explicitly. We focus on developing a general framework for deriving the parameters in this hybrid approach from existing DPD representations, and validate this new method via a comparison to DPD results. In addition, we consider a few proof of principle calculations for large systems, including a vesicle of realistic dimensions (∼45 nm radius) containing (104) lipids simulated for (106) time steps, to illustrate the performance of the new method.
The Delineation of an Oceanic Gas Hydrate Deposit

Abstract Accumulations of natural gas hydrate, a solid form of natural gas, are increasingly viewed as a potential economic natural gas resource since the estimated total global volume of methane in these deposits is significantly larger than that found in conventional gas reservoirs. In this study, which is the first attempt at delineating and characterizing potential oceanic hydrate bearing sediments in the Atlantic Continental Margin offshore Trinidad, three-dimensional seismic data were examined. Several positive indicators, such as the presence of bottom simulating reflectors (BSRs) were observed and mapped.
Stoichiometry of Cr(VI) Immobilization Using Nanoscale Zerovalent Iron (nZVI): A Study with High-Resolution X-Ray Photoelectron Spectroscopy (HR-XPS)

Remediation of chromium-contaminated sites presents both technological and economic challenges as conventional methods are often too expensive in removing chromium in the soil matrix such as chromium ore process residue (COPR). In this work, reduction and precipitation of hexavalent chromium [Cr(VI)] by nanoscale zerovalent iron (nZVI) are evaluated. Cr(VI) is rapidly reduced and immobilized on the iron nanoparticle surface. In the pH range of 4 to 8, the nZVI has a chromium removal capacity ranging from 180 to 50 mg Cr/g nZVI. Under similar conditions, microscale iron particles (100 mesh) typically have a capacity of less than 4 mg Cr/g Fe. Characterizations with high-resolution X-ray photoelectron spectroscopy (HR-XPS) indicate that Cr(VI) is reduced to Cr(III), which is subsequently incorporated into the iron oxyhydroxide shell of nZVI and form alloy-like Cr−Fe hydroxides with a representative formula approximating (Cr0.67Fe0.33)(OH)3 or Cr0.67Fe0. 33OOH. The Cr−Fe hydroxide shell is relatively stable a.
Influence of Porous Electrode Structure on PEM Fuel Cells Design and Performance

Gas flow in fuel cell porous electrodes is usually modelled with Darcy’s law, which requires the definition of a resistance constant for the material. This can be done directly via experimentation or indirectly via numerical tuning to fit experimental data on cell behaviour. Both methods lack generality, as they do not take into account the particular porous structure of each electrode. In the present work, a numerical procedure for calculating the resistance constant for a given porous structure is presented. This procedure is based on Lattice Boltzmann models, which treat the problem from a microscopic point of view, reproducing collisions between fluid molecules and solid particles. It can be demonstrated that under certain hypotheses, these models yield Navier-Stokes equations on a macroscopic scale, hence obeying fluid mechanics laws. Here the flow in a set of thirty randomly generated porous structures was analyzed, thus obtaining a distribution of values for Darcy’s constant. The analysis was repeated for ten different pressure gradients applied to a portion of the electrode and for three different volume porosities.
Hexavalent Chromium Reduction in Soils Contaminated with Chromated Copper Arsenate Preservative

The toxicity and mobility of chromium in the environment greatly depends upon its speciation. The reduction of hexavalent chromium to trivalent chromium in a soil environment was examined by spiking three soil types (sandy, clayey, and organic soils) with a common wood preservative solution known as chromated copper arsenate (CCA). Chromium in the CCA preservative solution exists in the hexavalent form. The total and hexavalent chromium concentrations (mg/kg) were measured over a period of 11 months. Leachable chromium concentrations (mg/L) were assessed using the synthetic precipitation leaching procedure (SPLP). The degree and rate of hexavalent chromium reduction were similar for the sand and clayey soil, but much greater for the organic soil. Most of the chromium reduction occurred within the first month of the experiment. At the end of the experiment, approximately 50% of the hexavalent chromium was converted to the trivalent form in the sand and clayey soils. Hexavalent chromium concentrations were below detection in the organic soil at the end of the experiment. Nearly all of the chromium observed in the SPLP leachates was in the form of hexavalent chromium. Chromium leaching was thus greatest in the sand and clay soils where the hexavalent chromium persisted. The results indicate that hexavalent chromium in soils can persist for considerable time periods, in particular in soils with low organic matter content. #Present affiliation for Jinkun Song: Graduate Research Assistant, Department of Civil Engineering, Texas A&M University, Texas 77843. **Present affiliation for Yong-Chul Jang: Assistant Professor, Department of Environmental Engineering, Chungnam National University, Daejeon 305-764, South Korea.