Miracle-dz/UniFAR-FTUs huggingface dataset:
Organic bulk heterojunction solar cells with improved efficiency

Organic solar cells have attracted considerable attention in recent years for their unique advantages, such as solution processing, flexibilities, and low cost for mass production. The highest power conversion efficiency reported so far is 6.5%. However, it is widely believed that the efficiency barrier of 10% has to be exceeded before polymer solar cells can be commercialized. Our study focuses on developing universal techniques for the improvement of the efficiency of organic solar cells and flexible polymer solar cells on two types of bulk heterojunction devices, i.e. poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and (poly[2-methoxy,5-(2-ethylhexoxy)-l,4-phenylene vinylene]) (MEH-PPV) and PCBM. The universal techniques we propose and demonstrate to achieve efficiency improvement include treatment of anode electrode by chemical and optical techniques, optimization of buffer layer, and device processing with additives. All reported organic solar cells of high efficiencies have been achieved under inert environment, among which some devices are either encapsulated devices or tandem devices. The polymer solar cells studied in this thesis are unencapsulated single cells tested at ambient environment. The efficiency of the P3HT:PCBM device with ITO substrate irradiated by UV light has been enhanced to 3.65%, as compared with the efficiency of 2.01%) from the device fabricated on untreated ITO substrate. To improve the efficiency of organic solar cell, we reveal an approach to effectively adjust the properties of the buffer layer, Poly(ethylene-dioxythiopene):poly(styrenesulfonate) (PEDOT:PSS), achieving an improvement in the efficiency from 2.08% to 2.92%. The properties of MEH-PPV:PCBM devices processed with either of the two additives, dimethyl sulfoxide (DMSO) or 1,8-octanedithiol (ODT) demonstrate significant increases in the efficiency, i.e., from 2.5%) to 2.8% after doped 2 vol% of ODT, and from 2.5% to 3.15% by doping 5 vol% of DMSO, surpassing the highest efficiency of MEH-PPV:PCBM solar cells reported so far. -- We demonstrate the operation of flexible solar cells, which are fabricated on polyethylene erephthalate (PET) substrates. Size effect on the performance of flexible solar cells indicates that the efficiency of the solar cell increase in the device size. The relationship between the efficiency and the bending angle of the flexible solar cells as well as the mechanisms of the degradation in efficiency are evaluated for the finite time.
Elastic, Electronic, and Optical Properties of Two-Dimensional Graphyne Sheet

The elastic, electronic, and optical properties of the 2D graphyne sheet, which consists of hexagonal carbon rings and acetylenic linkages, are investigated from first-principles calculations. Graphyne has a Poisson’s ratio of 0.417 and an in-plane stiffness of 10.36 eV/A2. Compared with graphene, graphyne is much softer because of its relatively smaller number of bonds. The band structure of graphyne is calculated using both generalized gradient approximation and hybrid functional, and the band gap predicted by the latter is twice as much as that given by the former. It is also shown that the energy bands of graphyne can be divided into several regions according to bonding character. The optical property of graphyne is found to be strongly anisotropic. For electric field parallel to the graphyne plane, strong optical adsorption is observed in low-energy region, whereas for the electric field perpendicular to the graphyne plane, the adsorption in the low-energy region is very weak. What’s more, the respon.
Determination of the Content of Total Saponins in the Husks of Xanthocer as Sorbifolia Bunge

Objective:To study the assay method of total saponins in the husks of Xanthoceras sorbifolia Bunge. Method:UV-spectral method was used. Selecting ginsenoside-Re as control sample,colorating with perchloric acid,determining abso-rbability in the point of 321nm by adopting spectrophotometric method,then calculating total saponins content in the husks of Xanthoceras sorbifolia Bunge. Results:The linear relationship is good for ginsenoside-Re in scope of 0.18-0.50mg(r=0.9995). The average recovery was 98.45% and RSD was 1.77%. Conclusion:This method is simple,accurate and sensitive with good reproducibility and it can be used as a determinational method of total saponins for the husks of Xanthoceras sorbifolia Bunge.
Firm Responsiveness to Consumers’ Reviews: The Effect on Online Reputation

This paper investigates whether firms’ responsiveness to customer reviews affects firms’ online reputation. Responsiveness is measured by the intensity (fraction) of reviews that are responded to whereas online reputation is measured using TripAdvisor’s average customer review rating (1-5 scale). Our analysis is applied to the hotel market in Manhattan (New York). To deal with the endogeneity of a hotel’s responsiveness, we instrument it with the responsiveness level displayed by nearby competitors. This identification strategy is motivated by the fact that hotels have a greater tendency to respond to reviews not only because a particular review demands attention, but also because they seek to comply (catch up) with their competitors’ level of responsiveness. The results show that one standard deviation increase in a hotel’s responsiveness level would result in an improvement of 0.055 stars in TripAdvisor’s average online rating (equivalently, an increase of 0.09 SD). Importantly, not accounting for endogeneity would lead to an erroneous conclusion that such effect is non-existent. In addition, our results show that the effect is heterogeneous. Specifically, the effect is particularly strong for: a) hotels responding more intensely to negative reviews, b) independent hotels (vis-à-vis chain hotels), c) hotels with a less established online reputation, d) hotels with more volatile online ratings, and e) hotels with more experience responding to negative reviews. We discuss the possible mechanism between firms’ responsiveness and online reputation.
The Challenges of Oil Investing: Contango and the Financialization of Commodities

Abstract The ability of oil investment vehicles to perfectly track spot oil has always been challenging , however recently many vehicles have underperformed spot oil. We study the behavior of oil futures and exchange-traded products that invest in oil futures to document and understand the source of this tracking error. The primary reason that oil investment vehicles have underperformed spot oil is due to an increase in contango in oil futures markets that we find might be related to investment crowding and the financialization of commodity markets. We show that from 2006 to 2017 oil futures investing underperformed spot oil and the market was in contango most of the time. Proxies for crowding, such as the concentration of major oil investors and changes in assets under management and fund flows of major oil exchange-traded products are associated with contango in the futures markets and the divergence between futures and spot returns. We also provide evidence of an impact of the financialization on oil futures prices.
Study of the Relationship Between Electrical and Magnetic Properties and Jahn-Teller Distortion in R 0.7 Ca 0.3 Mn 0.95 Fe 0.05 O 3 Perovskites by MÖSSBAUER Effect

In this work structural, magnetic and electrical properties of R0.7Ca0. 3Mn0.95Fe0. 05O3 (R= Pr and Nd) perovskite manganites are presented. Structural characterization of these compounds shows that both have orthorhombic (Pbmn) phase. The Mossbauer spectra show clear evidence of the local structural distortion of the Mn(Fe)O6 octahedron on the basis of non-zero nuclear quadrupole interactions for high-spin Fe3+ ions. It was found that the local structural distortion decreases significantly with replacing Pr3+ by Nd3+. This replacing dependence of the Jahn–Teller coupling strength estimated from the Mossbauer results was found to be consistent with the electrical and magnetic properties.
Linear and Branched Pyridyl–Oxazole Oligomers: Synthesis and Circular Dichroism Detectable Effect on c‐Myc G‐Quadruplex Helicity

Five unprecedented pyridyl–oxazole oligomers exhibiting either linear or branched connectivity of their subunits were developed as a family of potential G-quadruplex-interacting ligands. Our synthesis employed variations of a key Pd/Cu-mediated C–C cross-coupling/C–H activation reaction to gain access to the oligomer products from a small set of substituted pyridine building blocks. The effect of the compounds on the conformation of a c-myc oncogene promoter G-quadruplex was investigated by circular dichroism under various conditions. Some or all of the compounds induced detectable helicity enhancement in low-cation and Na+-rich Tris-HCl (pH 7.4) buffers, respectively, in which the helix was only partially prefolded.
Multi-method characterization of the ferrihydrite to goethite transformation

Abstract The reactivity of soils and sediments is often described by parameters such as the specific surface area (SSA) and the cation exchange capacity (CEC). Both, however, are bulk values controlled by the presence and crystallinity of different phases, e.g. clay minerals and iron oxides. Amongst the latter, ferrihydrite and goethite are the most abundant minerals. Goethite gradually forms from a ferrihydrite precursor, a process involving a decrease in surface area. Today the BET gas adsorption technique is the most common method to measure SSA. In this study, BET surface areas of synthetic and natural ferrihydrite and goethite of variable crystallinity were compared to (a) mineral-specific measurements, including infrared analysis (IR), differential thermal analysis (DTA), and (b) bulk methods, such as cation exchange capacity and oxalate-soluble iron. Correlations showed that the SSA can be indirectly inferred from all methods. There is no general correlation between IR and BET measurements due to the variability of adsorbed water, which depends on drying and ambient conditions. DTA, particularly using the dehydroxylation peak at 300ºC, allows quantification of the goethite content, and hence the SSA, because adsorbed water does not affect this peak. The data set of the present study enabled us to estimate either SSA and/or the content of iron oxides, even in natural mixtures, e.g. those in which smectites determine the SSA.
Contenido de lípidos, ácidos grasos, exopolisacáridos y minerales de Arthrospira máxima cultivada en fotobiorreactores

Esta investigacion planteo la evaluacion de la composicion bioquimica de la biomasa de Arthrospira maxima obtenida en fotobiorreactores, bajo condiciones ambientales controladas. A tal efecto, esta cianobacteria fue cultivada de forma discontinua en fotobiorreactores helicoidales y cilindricos, durante 30 d en medio Zarrouk. El crecimiento poblacional analizado, a traves de la determinacion de la biomasa seca, fue mayor en el fotobiorreactor helicoidal (1,37 mg ml-1). El mayor contenido de exopolisacaridos se encontro en el fotobiorreactor helicoidal a los 12 d de cultivo. En ambos sistemas de cultivo se detectaron saponinas, esteroles insaturados y alcaloides. El contenido promedio de lipidos totales obtenido en los fotobiorreactores helicoidales (6,05 ± 0,012%) no mostro diferencias signifi cativas (P>0,05) con los determinados en los fotobiorreactores cilindricos (5,76 ± 0,038%). El acido palmitico fue el acido graso que se encontro en mayor proporcion (fotobiorreactor helicoidal = 43,84 ± 0,922% y fotobiorreactor cilindrico = 44,87 ± 3,094%). Los acidos grasos poliinsaturados 18:2n-6 y 18:3n-6 mostraron concentraciones similares en ambos tipos de fotobiorreactores (16 a 18%). Al culminar esta investigacion se deja en evidencia que los dos sistemas de cultivo evaluados permiten obtener biomasa de Arthrospira maxima con altos contenidos de lipidos totales y acidos grasos, ademas de minerales y compuestos quimicos de interes para la medicina, las industrias farmaceuticas y alimenticias.
Etude de l'anode pour la pile à combustible directe aux borohydrures

Le travail presente dans cette these porte sur l'anode de la pile a combustible directe aux borohydrures (DBFC, selon l'acronyme anglais). Une premiere approche pour developper l'anode de la DBFC est d'etudier cette anode a l'interieur du systeme global de la DBFC. Dans cette optique, des anodes composees des catalyseurs Pt/C et Pd/C ont ete caracterisee en banc de test DBFC. D'autres facteurs ont aussi ete etudies, tels que la morphologie de l'anode et la stabilite des nanoparticules des catalyseurs.Le catalyseur d'anode de la DBFC doit idealement exhiber une activite catalytique suffisante pour la reaction d'oxydation des borohydrures (BOR), tout en minimisant la production et l'echappement d'hydrogene gazeux durant la BOR. Ces aspects sont relativement difficiles a etudier en raison des nombreuses variables ne dependant pas de l'anode dans un systeme DBFC reel. Une solution a ce probleme consiste a isoler l'anode de la DBFC et de l'etudier en configuration demi-pile, avec un environnement d'etude mieux controle. Les differentes methodes pour evaluer un catalyseur d'anode de DBFC en demi-pile sont discutees, et des marqueurs sont proposes pour l'evaluation pertinente d'un catalyseur d'anode de DBFC par rapport aux resultats de la litterature.Une autre strategie possible pour developper des catalyseurs adequats d'anode de DBFC est de mieux comprendre le mecanisme de la BOR. Dans cette optique, la BOR est etudiee sur des electrodes modeles a base de platine. Chaque type d'electrode modele permet de controler un parametre precis de la surface catalytique, menant ainsi a differentes etudes de la BOR. La sensibilite de la BOR a la structure de surface catalytique est etudiee sur des electrodes massives de platine (polycristallin et monocristallin). L'empoisonnement de la surface active de Pt durant la BOR est etudie sur nanoparticules de Pt deposees sur substrat carbone vitreux plan. Des electrodes a trois dimensions ont egalement ete realisees : nanoparticules de Pt deposees sur nanofibres de carbone verticalement alignees. Le depot de differentes quantite de Pt a permis d'etudier l'influence de la densite en sites actifs de Pt sur la BOR. Les resultats obtenus sur ces electrodes modeles sont discutes avec ceux de la litterature, et un mecanisme pour la BOR sur Pt est propose. Ce mecanisme est simule en utilisant une modelisation de micro-cinetiques de type champs moyens. Les courbes simulees reproduisent les caracteristiques majeures des resultats experimentaux.
Estudo das interações do herbicida glifosato com argila natural brasileira monoionica

Neste trabalho estudou-se a adsorcao do glifosato em argila (montimorilonita), monoionica com Na, Cu, Ca, Al e Zn. A montimorilonita utilizada e do tipo bentonita, da regiao de Boa Vista, Campina Grande, Paraiba,e foi caracterizada por difratometria de raios-X, microscopia eletronica de varredura, espectroscopia do infravermelho, analise quimica, capacidade de troca ionica, area superficial, analise termogravimetria e calorimetria diferencial de varredura (DSC). Os processos de adsorcao de glifosato pelas argilas monoionicas mostraram valores maximos de adsorcao na seguinte ordem: Arg-Na<Arg-Ca<Arg-Zn<Arg-Al<Arg-Cu. Em relacao ao pH, observou-se que em pH 6,5, a adsorcao e maior que em pH 3,0. Em relacao a temperatura, os processos de adsorcao sao mais intensos quando se diminui a temperatura. Os estudos utilizando-se a calorimetria mostraram que a formacao de complexos ion metalico-glifosato, sao endotermicas para aluminio e cobre e exotermicas para calcio e zinco. Entretanto, em meio heterogeneo, envolvendo as argilas, todos os processos se mostraram exotermicos, o que evidencia a grande importância relativa da matriz argila no processo como um todo. Ha que se acrescentar que os estudos calorimetricos envolvendo as adsorcoes de glifosato nas argilas nao sao completos em vista de dificuldades experimentais na obtencao dos resultad
Climate and the Role of the Sun

It is true that from the highest point of view the sun is only one of a multitude-a single star among millions-thousands of which, most likely, exceed him in brightness, magnitude, and power. He is only a private in the host of heaven. But he alone, among the countless myriads, is near enough to affect terrestrial affairs in any sensible degree; and his influence upon them is such that it is hard to find the word to name it; it is more than mere control and dominance.1
Nonlinear Bioprocess Monitoring Using Multiway Kernel Localized Fisher Discriminant Analysis

A novel batch bioprocess monitoring approach based on multiway kernel localized Fisher discriminant analysis (MKLFDA) is proposed in this article. For the routine bioprocess operation with some abnormal events, a supervised monitoring method is needed to handle the training data set that includes various types of faulty samples. Because of the inherent process nonlinearity and multimodality among normal and faulty clusters, the traditional multiway Fisher discriminant analysis (MFDA) method becomes inappropriate and unable to effectively detect or classify faulty samples. The newly developed MKLFDA approach, however, combines kernel function with the localized Fisher discriminant analysis so that the “kernel” feature can retain the process nonlinearity while the “localized” characteristic is able to extract the multi-Gaussianity within data clusters. Furthermore, the integrated multiway analysis uses batch-wise unfolding to convert the three-dimensional data set into a two-dimensional matrix that can be f.
Algorithm for Gesture Recognition Using an IR-UWB Radar Sensor

This paper introduces a human gesture recognition algorithm using an impulse radio ultra-wide- band (IR-UWB) radar sensor. Human gesture recognition has been one of the hottest research topics for quite a long time. Many gesture recognition algorithms or systems using other sensors have been proposed such as using cameras, RFID tags and so on. Among which gesture recognition systems using cameras have been extensively studied in past years and widely used in practical. While it might show some deficiencies in some cases. For example, the users might not like to be filmed by cameras considering their privacies. Besides, it might not work well in very dark environments. While RFID tags could be inconvenient to many people and are likely to be lost. Our gesture recognition algorithm uses IR-UWB radar sensor which has pretty high resolution in ranging and adjustable gesture recognition range, meanwhile, does not have problems in privacy issues or darkness. In this paper, the gesture recognition algorithm is based on the moving direction and distance change of the human hand and the change of the frontal surface area of hand towards radar sensor. By combining these changes while doing gestures, the algorithm may recognize basically 6 kinds of hand gestures. The experimental results show that these gestures are of quite good performance. The performance analysis from experiments is also given.
Amorphous Carbon with SO3H Groups as a Solid Brønsted Acid Catalyst

Homogeneous Bronsted acid catalysts such as H2SO4 and HCl are used for the production of industrially important chemicals. However, their use requires significant energy costs for separation, reuse, and treatment of salt wastes. Alternatively, heterogeneous Bronsted acid catalysts are promising candidates that can decrease the environmental impact associated with chemical production. In this review, we highlight amorphous carbon bearing SO3H groups as an insoluble Bronsted acid available for various acid-catalyzed reactions.
The Origin of Slow Carrier Transport in BiVO4 Thin Film Photoanodes: A Time-Resolved Microwave Conductivity Study

We unravel for the first time the origin of the poor carrier transport properties of BiVO4, a promising metal oxide photoanode for solar water splitting. Time-resolved microwave conductivity (TRMC) measurements reveal an (extrapolated) carrier mobility of ∼4 × 10–2 cm2 V–1 s–1 for undoped BiVO4 under ∼1 sun illumination conditions, which is unusually low for a photoanode material. The poor carrier mobility is compensated by an unexpectedly long carrier lifetime of 40 ns. This translates to a relatively long diffusion length of 70 nm, consistent with the high quantum efficiencies reported for BiVO4 photoanodes. Tungsten (W) doping is found to strongly decrease the carrier mobility by introducing intermediate-depth donor defects as carrier traps. At the same time, the increased carrier density improves the overall photoresponse, which confirms that bulk electronic conductivity is one of the main performance bottlenecks for BiVO4.
Self-duality of the lattice of transfer systems via weak factorization systems

Let $p$ be a prime. A pro-$p$ group $G$ is said to be 1-smooth if it can be endowed with a homomorphism of pro-$p$ groups $G\to1+p\mathbb{Z}_p$ satisfying a formal version of Hilbert 90. By Kummer theory, maximal pro-$p$ Galois groups of fields containing a root of 1 of order $p$, together with the cyclotomic character, are 1-smooth. We prove that a finitely generated $p$-adic analytic pro-$p$ group is 1-smooth if, and only if, it occurs as the maximal pro-$p$ Galois group of a field containing a root of 1 of order $p$. This gives a positive answer to De Clerq-Florence's"Smoothness Conjecture"- which states that the Rost-Voevodsky Theorem (a.k.a. Bloch-Kato Conjecture) follows from 1-smoothness - for the class of finitely generated $p$-adic analytic pro-$p$ groups.
New perspective in searching for axionlike particles from flavor physics

We propose new perspective in searching for axion-like particles (ALPs) from quark and lepton flavor physics: measurements of the time-dependent CP asymmetry in B → K Sπγ and the branching ratio of Bs → e±μ∓ decay possess, along with the anomalous magnetic moment of muon. In the mass range of sub-GeV, accessible by the flavorful ALPs search, the experimental sensitivity for these flavor observables reaches the maximum at around the pion mass scale (called the sweetest spots), where a couple of loopholes (unexplored regions) for the ALP parameter space have heretofore been present, because of an unavoidable contamination with pion background events. The proposed complementary probes can precisely determine the ALP coupling to photon at these sweetest spots/loopholes, and will significantly help cover whole parameter spaces in the ALP search including the present loopholes in the future.