Miracle-dz/UniFAR-FTUs huggingface dataset:
Quantum dot in a well infrared photodetectors for high operating temperature focal plane arrays

InAs quantum dots embedded in InGaAs quantum wells with InAlAs barriers on InP substrate grown by metalorganic chemical vapor deposition are utilized for high operating temperature detectors and focal plane arrays in the middle wavelength infrared. This dot-well combination is unique because the small band offset between the InAs dots and the InGaAs well leads to weak dot confinement of carriers. As a result, the device behavior differs significantly from that in the more common dot systems that have stronger confinement. Here, we present energy level modeling of our QD-QW system and apply these results to interpret the detector behavior. Detectors showed high performance with D* over 1010 cmHz1/2/W at 150 K operating temperature and with high quantum efficiency over 50%. Focal plane arrays have been demonstrated operating at high temperature due to the low dark current observed in these devices.
Long-term tillage and drainage influences on soil organic carbon dynamics, aggregate stability and corn yield

Abstract Labile pools of soil organic carbon (SOC) and nitrogen (N) are affecting the carbon (C) and N fluxes in the terrestrial soils, whereas long-term C and N storage is determined by the long-lived recalcitrant fractions. Tillage and subsurface drainage influences these pools; however, the effect of these systems on poorly drained soils may be different. Therefore, the present study was conducted on a field experiment, established at the Waterman Farm of the Ohio State University in 1994. Specific objectives of the study are to assess the influence of no-tillage (NT), chisel tillage (CT) with drainage (TD) and non-drainage (ND) management under a continuous corn (Zea mays L.) system on SOC, C fractions (heavy and light), and water stable aggregates (WSA). Data from this study showed that the SOC stock for the NT was 25, 37 and 32% higher for the 0–10, 10–20 and 40–60 cm depths, respectively, as compared to that under CT system. Tillage significantly influenced the light fraction (LF) and heavy fraction (HF) of carbon. The NT system increased LF and HF by 10 and 12%, respectively, compared to CT for the 0–10 cm depth. Eighteen years of NT management decreased soil bulk density and improved macroaggregates and mean weight diameter compared to that under CT system. Drainage impacts on soil parameters were negligible, and may be partially due to the reason that the corn-corn cropping system may not have sufficiently improved the soil properties between the two tillage systems. In general, drainage improved porosity and the corn yield. It can be concluded that NT with subsurface management improves SOC dynamics and promotes aggregation and corn yield as compared to that with CT system.
Monomeric and Cluster States of Water Molecules in Organic Solvent

Measurements of the 1H-NMR chemical shifts and their temperature dependence have disclosed that sparingly soluble water is monomeric at room temperature in hydrophobic solvents, such as carbon tetrachloride, benzene, chloroform, and that some water clusters are formed even in dilute solution in the apolar and slightly polar solvents at low temperatures, controlled by energy instead of entropy.
Effect of ethylene carbonate on the ionic conduction in poly(vinylidenefluoride-hexafluoropropylene) based solid polymer electrolytes

Polymer electrolytes based on poly(vinylidenefluoride-hexafluoropropylene) (PVdF-HFP) as the polymer host, lithium trifluoromethanesulfonate (LiTf) as the salt and ethylene carbonate (EC) as the plasticizer, has been prepared by a solution casting technique. Addition of LiTf resulted in an increase in the electrical conductivity of polymer. EC will act to increase the degree of salt dissociation and also ionic mobility. The highest ionic conductivity achieved at room temperature was for PVdF-HFP + LiTf : EC (60 : 40) with the conductivity ∼10−3 S cm−1. The conductivity of the polymer electrolyte increases with the increase in amount of plasticizer. The interaction of the PVdF-HFP, LiTf and EC were analyzed by Fourier transform infared (FTIR). The temperature dependent conductivity, frequency dependent conductivity, dielectric permittivity (e/) and modulus (M/) studies were carried out. Thermo gravimetric analysis (TGA) reveals that the thermal stability of polymer electrolytes decreases with the increase in EC content.
Gold Recovery from HCl Solutions using Cyphos IL‐101 (a Quaternary Phosphonium Ionic Liquid) Immobilized in Biopolymer Capsules

Tetraalkyl phosphonium chloride (Cyphos IL‐101), an ionic liquid (IL), was tested for gold recovery from HCl solutions: first in liquid/liquid extraction systems (using toluene and hexane as solvent) and in a second step, after being immobilized in a biopolymer composite matrix. SEM‐EDAX analysis was used for the characterization of the resins. The sorption capacity reached up to 140 mg Au(III) g−1 in 1 M HCl solutions. Base metals that do not form anionic chlorocomplexes and nitrate or chloride ions (at 5 g L−1) did not interfere with Au(III) binding. Gold binding probably occurs through the interaction of R3R'P+ with AuCl4 −. The kinetics of sorption was carried out varying agitation speed, metal concentration, IL content, and resin drying. Intraparticle diffusion played an important role on the control of sorption kinetics. Gold could be desorbed from the loaded IL‐impregnated resin using thiourea (in HCl solutions). The resin could be re‐used for at least 4 cycles. The resins are specially adapted for the recovery of gold from low metal concentrations.
Mosquitoes composition, abundance and distribution in swampy and flooded shoreline habitats of Lake Baringo, Kenya, during a period of extreme flooding (2012-2013)

Mosquito ecology is influenced by wetness in the environment. In 2011-2014, a rise in waters of Lake Baringo resulted in unprecedented flooding that inundated over 88km of the shoreline. A longitudinal study carried out from October 2012-October 2013 assessed mosquito abundance and diversity in two habitats. A total of 386,624 mosquitoes were captured, 89% from flooded shoreline and 11% from swampy habitat. Family Culicinae constituted 10 genera. Mansonia dominated the catches with 98% from flooded shoreline and swampy habitat 2%. Genetic sequences of Aedes albopictus species was identified and reported for the first time in the basin. Diversity index was higher in swampy habitat (Simpson Diversity Index=0.56), compared to flooded shoreline (Simpson diversity index =0.13). Future recurring floods will result in drastic changes of the ecology and could lead to emergence and reemergence of more species.
ZnO Oxygen Vacancies Formation and Filling Followed by in Situ Photoluminescence and in Situ EPR

Oxygen vacancies of zinc oxide were followed by photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopies. The green PL emission was associated with oxygen vacancies: its intensity is enhanced upon static thermal treatment under inert or under vacuum, whereas it decreases upon oxygen treatment. A unique EPR signal at g = 1.96 was measured at room temperature after thermal in situ treatment under flow of inert or oxygenated atmospheres, its double integration follows the same trends than the green PL emission and its evolution was shown to probe the oxygen vacancy concentrations. The relative concentration of the related paramagnetic species would be increased/decreased upon trapping/release of the electron associated to the formation/filling of oxygen vacancy. The influence of Ti impurities on the PL and RPE signals was investigated. Finally, it is concluded that the EPR signal is related to oxygen vacancies and its position shift could be explained by the involvement of some mixing .
Metal ions and complexes in organic reactions. Part IX. Copper(I)-catalysed conversion of aryl halides into alkyl aryl ethers

Whereas sodium alkoxides reduced aryl halides (ArHal → ArH) under heterogeneous catalytic conditions, e.g., in solutions containing a suspension of copper(I) oxide, reaction could in some cases be diverted to nucleophilic sustitution (ArHal → ArOAlk) by operating with a substantially homogeneous liquid medium containing copper(I) salts as catalysts. In a suitably chosen reaction system, e.g., ArHal–NaOAlk–AlkOH–Cul–2,4,6-collidine, at ∼100–120°, high yields of ethers resulted with alkoxides derived from normal monohydric alkanols, but reduction usually predominated with alkoxides from other types of alcohols. The process is exemplified by preparations of methyl or ethyl ethers (∼80–100%) from monocyclic or polycyclic aryl bromides or iodides, including those containing Me, OMe, or CO2H groups as nuclear substituents. Lower yields (∼35–50%) resulted when OH or NH2 were substituents, probably because of their participation in competing reactions, and no ethers were obtained when NO2,CHO, or COMe were substituents.
Dynamic Mechanical Study of the Factors Affecting the Two Glass Transition Behavior of Filled Polymers. Similarities and Differences with Random Ionomers

The dynamic mechanical measurements on several polymers filled with very fine silica particles revealed that these composites exhibit two tan δ peaks. One was related to the usual polymer glass transition, while the other, occurring at a higher temperature, was assigned to the glass transition of regions containing chains of reduced mobility. Since many aspects of this behavior were found to be analogous to those of random ionomers, the results support the validity of the EHM model of ionomer morphology. The particle content, the number of monomer units interacting strongly with the surface of the particles, the thermal history of the sample, and the average MW of the polymer were all found to have a significant effect on the area and the maximum of the new tan δ peak. These effects are discussed in terms of a model which is based on the EHM ionomer model but takes into account the formation of tightly bound and loosely bond polymer chains around the filler particles.
Influence of SrTiO3 Buffer Layer on the Ferroelectric Properties of Bi2NiMnO6 Thin Film

Double perovskite Bi2NiMnO6 (BNMO) thin films with and without SrTiO3 (STO) buffer layer have been prepared on Pt (111)/Ti/SiO2/Si(100) substrates by a chemical solution deposition method. The microscopic surface morphology, ferroelectric, and leakage current have been investigated. It is shown that the STO buffer layer can improve the remnant polarization slightly, and reduce the coercive electric field from 100 to 36 kV/cm. When the positive voltage was applied on top Au electrode of the BNMO/STO/Pt thin film capacitors, the leakage current was controlled by ohmic conduction. When the negative voltage was applied on bottom Pt electron, the leakage current of BNMO/STO thin film was limited by the traps and the density of carriers at high electric field.
Über die Gerbstoffe aus dem Holz der Edelkastanie und der Eiche, II. Die Isolierung von Castalagin, Vescalagin, Castalin und Vescalin

Durch Chromatographie an Cellulosepulver gelang es, aus dem Gesamtgerbstoff des Edelkastanienholzes (Castanea sativa) und des Eichenholzes (Quercus sesseliflora) vier chemisch einheitliche Verbindungen abzutrennen, die als Castalagin, Vescalagin, Castalin und Vescalin bezeichnet werden. – Castalagin und Vescalagin sind kristallisiert und besitzen die gleiche Summenformel. Castalagin liefert bei der Hydrolyse Ellagsaure und Castalin, Vescalagin ergibt hierbei Ellagsaure und Vescalin. Auch Castalin ist kristallisiert und isomer mit Vescalin. Beim Erhitzen in wasriger Losung wandeln sich Castalagin in Vescalagin und Castalin in Vescalin um.
Mini-Review: Biosynthesis of Poly(hydroxyalkanoates)

Polyhydroxyalkanoates (PHAs) are biologically produced polyesters which can consist of a diverse set of repeating unit structures. These biologically produced polyesters have many attractive properties and have been produced for use as bulk commodity plastics, fishing lines, and medical uses. PHAs have also attracted much attention as biodegradable polymers that can be produced from biorenewable resources. The cellular factories that produce these polymers offer the ability to produce or incorporate monomers that may not be available via typical chemical synthesis. In addition, cellular production of PHAs may be more “green” as compared to the use of specific metal catalysts for the production of polymers. The biosynthetic incorporation of specific monomers into PHA polymers is dependent on many factors that include the type of carbon source that the organism is grown on, the types of metabolic pathways available to that organism to convert those carbon sources into PHA monomers, and the substrate specificity of the enzymes involved in PHA synthesis. This review covers known biosynthetic pathways for the production of PHAs.
Porphyrin-containing glycodendrimers

Two dendrimers, incorporating tetrasubstituted porphyrin units as their cores and, in one case, four perbenzoylated and, in the other case, twelve peracetylated β-D-glucopyranosyl residues at their peripheries, have been synthesized in yields of 39 and 16%, respectively. The deprotection of these dendrimers was achieved quantitatively under Zemplen conditions. The protected and deprotected dendrimers were characterized by liquid secondary-ion or matrix-assisted laser desorption ionization time-of-flight mass spectrometry and by a combination of one- and two-dimensional 1H and 13C NMR spectroscopy. All the glycodendrimers were also characterized by absorption and emission spectroscopy, and lifetime measurements. The most relevant result is that both protected and deprotected dendrimers show two fluorescence lifetime values that are different from the porphyrin model compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Mechanistic Aspects of Alkylchlorosilane Coupling Reactions

Toluene solutions of monochlorosilane and trichlorosilane coupling agents are shown to react differently with hydrated and dry silicon surfaces. For typical hydrated surfaces produced by piranha (H2O2 + H2SO4) etching, the saturation coverages of octadecyldimethylchlorosilane (ODMS) (one reactive Si−O bond) are approximately a third that of octadecyltrichlorosilane (ODTS) (three reactive Si−O bonds). In contrast, for samples vacuum baked at 400 °C, the saturation coverages of ODTS and ODMS are comparable. These data are consistent with coupling reactions limited to the surface hydroxyl groups. The ODTS saturation coverage on vacuum-fired silicon samples can be increased by soaking in water followed by a second ODTS exposure. From X-ray photoelectron spectra (XPS) and secondary ion mass spectra (SIMS) obtained as a function of solution exposure time, saturation coverage is shown to take at least 2 h and to be limited by the concentration of surface hydroxyl groups; a direct correlation is seen in SIMS betw.
How do populations aggregate?

BACKGROUND Understanding the relationship between populations at different scales plays an important role in many demographic analyses. OBJECTIVE We show that when a population can be partitioned into subgroups, the death rate for the entire population can be written as the weighted harmonic mean of the death rates in each subgroup, where the weights are given by the numbers of deaths in each subgroup. This decomposition can be generalized to other types of occurrence-exposure rate. Using different weights, the death rate for the entire population can also be expressed as an arithmetic mean of the death rates in each subgroup. CONTRIBUTION We use these relationships as a starting point for investigating how demographers can correctly aggregate rates across non-overlapping subgroups. Our analysis reveals conceptual links between classic demographic models and length-biased sampling. To illustrate how the harmonic mean can suggest new interpretations of demographic relationships, we present as an application a new expression for the frailty of the dying, given a standard demographic frailty model.
The changing of urban habits during the Corona pandemic in Sweden

During the Corona pandemic, extensive interventions have been introduced to limit the spread of Covid-19 Authorities, companies, and organisations introduce comprehensive restrictions To capture new routines, we launched a web questionnaire (PPGIS) including maps in three cities in Sweden;Stockholm, Uppsala and Gothenburg From the first month results, we see dramatic changes of habits Places still used are primarily where people find service, while places people avoid are where they normally work or study Places used more, are where people find seclusion;primarily green spaces and easy to access This pandemic reinforces existing urban inequalities Access to urban resources and green spaces becomes even more important in areas characterized by poverty and overcrowding © 2020 Festival Architettura Edizioni All rights reserved
Graphene oxide and lithium amidoborane: a new way to bridge chemical and physical approaches for hydrogen storage

The incorporation of lithium amidoborane (LiAB) into graphene oxide (GO) and the dehydrogenation process of the GO–LiAB complex have been investigated for combining the chemical and physical hydrogen storage approaches. The obtained adsorption energy and minimum energy pathway (MEP) demonstrate that both of the two dominant groups of –O– and OH– contribute to the facile combination of GO and LiAB (GO3–LiAB). The GO3–LiAB complex has a better dehydrogenation performance than the pristine LiAB, which also indicates the feasibility of doping Li atoms on the GO surface. Atomic charge and bond length analyses match well with the MEP prediction. By dehydrogenation of the GO3–LiAB complex, we also achieve uniform metal doping on the GO surface for physisorption of H2. The GO–Li(n) products can store up to 5 wt% H2 and the GO–(Li3N3B3)(n) can still store 5 wt% H2. The dehydrogenation product of the GO3–LiAB complex has bridged the chemical and physical hydrogen storage approaches to move towards on-board hydrogen storage applications, which expands the scope for designing more efficient hydrogen storage materials.
Ionic conductivity and mobility in network polymers from poly(propylene oxide) containing lithium perchlorate

Ionic conductivity σ and mobility μ in the amorphous network polymers from poly(propylene oxide) (PPO) containing lithium perchlorate (LiClO4) at the concentration of [LiClO4]/[PO unit]=0.042 and 0.076 were investigated by means of complex impedance and time‐of‐flight methods. The σ values of the PPO–LiClO4 complexes reached 10−5 S cm−1 at 70 °C. The temperature dependence of σ deviated from a single Arrhenius behavior above a critical temperature (−1 °C and 11 °C) which approximately corresponded to the glass transition temperature Tg. The μ values were relatively high and changed from 10−6 to 10−5 cm2 V−1 s−1 in the temperature range of 40–100 °C. The Nernst–Einstein equation correlated μ with the ionic diffusion coefficient D. The Williams–Landel–Ferry equation with C1≂5 and C2≂30–50 held with a temperature dependence of D in the order of 10−8–10−7 cm2 s−1. The change in the number of ionic carriers n with temperature obeyed the Arrhenius equation with the activation energy of 0.26 and 0.34 eV. The deg.
The Solvent Extraction of Bivalent Metal Picrates by 15-Crown-5, 18-Crown-6, and Dibenzo-18-crown-6

The overall extraction equilibrium constants (Kex) for the 1:1:2 complexes of 15-crown-5 (15C5), 18-crown-6 (18C6), and dibenzo-18-crown-6 (DB18C6) with several bivalent metal picrates between benzene and water have been determined at 25 °C. The Kex sequences of the bivalent metal ions with 15C5, 18C6, and DB18C6 are Pb2+>Sr2+>Ba2+>Ca2+, Pb2+>>Ba2+=Sr2+>Hg2+>Ca2+, and Pb2+>Hg2+>Sr2+>Ca2+ respectively. To clarify the role of the crown ether in the extraction process, the three constituent equilibria have been investigated: the stability and the extractability of the bivalent metal ion-crown ether complex, and the distribution coefficient of the crown ether. The extractability of the bivalent metal ion-crown ether complex about the same bivalent metal ion increases with increasing size of the crown ether, and appears to be dependent on the chemical nature of the bivalent metal ion trapped in the cavity of the crown ether.
Biosorption of Pb(II) onto Cocos Nucifera Shell and Moringa Oleifera Seeds

The biosorption properties of Cocos nucifera shell and Moringa oleifera seeds for Pb(II) were investigated under batch mode. The optimum pH values obtained for the removal of Pb(II) by the Cocos nucifera shell and the Moringa oleifera seeds were 5 and 2, respectively. The equilibrium biosorption capacities obtained were 2.3 mg g−1 (Moringa oleifera seeds) and 1.6 mg g−1 (Cocos nucifera shell). The Freundlich isotherm model described the removal of Pb(II) by the biosorbents better than the Langmuir model. The Cocos nucifera shell sorbed 83.34% of the Pb(II) ions in 30 min, while 94.03% was sorbed by the Moringa oleifera seeds in the same time. The results indicated a fast kinetics for Pb(II) sorption by the biosorbents investigated. The biosorption of Pb(II) onto Cocos nucifera shell and Moringa oleifera seeds followed the pseudo second-order kinetics with R2 values of 0.9997 and 0.9999, respectively. The second-order rate constant (k2) obtained were 0.205 g mg−1 min−1 (Cocos nucifera shell) and 0.067 g mg−1 min−1 (Moringa oleifera seeds). The results indicate that intraparticle diffusion controls the rate of biosorption in this study. This study shows that Cocos nucifera shell and Moringa oleifera seeds can be important low-cost biosorbents for Pb(II) ions.
Effects of TiO2 Surface Fluorination on Photocatalytic Reactions and Photoelectrochemical Behaviors

The formation of surface fluorides on TiO2 (F−TiO2), which can be easily attained by a simple addition of F- to aqueous TiO2 suspensions, uniquely affects both photocatalytic reactions and photoelectrochemical behaviors. The fluoride adsorption is favored at acidic pH and greatly reduces the positive surface charge on TiO2 by replacing ⋮Ti−OH2+ by ⋮Ti−F species. Effects of surface fluorination on the photocatalytic reactivities are very different depending on the kind of substrates to be degraded. F−TiO2 is more effective than pure TiO2 for the photocatalytic oxidation of Acid Orange 7 and phenol, but less effective for the degradation of dichloroacetate. It is proposed that the OH radical mediated oxidation pathways are enhanced on F−TiO2, whereas the hole transfer mediated oxidations are largely inhibited due to the hindered adsorption (or complexation) of substrates on F−TiO2. As for the photocatalytic reduction, the dechlorination of trichloroacetate is much reduced on F−TiO2. The photocurrents collec.