(𝓕, 𝓐)-GORENSTEIN FLAT HOMOLOGICAL DIMENSIONS

Becerril, Victor Korean Mathematical Society 2022 대한수학회지 Vol.59 No.6

In this paper we develop the homological properties of the Gorenstein (𝓛, 𝓐)-flat R-modules 𝓖𝓕_{(𝓕(R),𝓐)} proposed by Gillespie, where the class 𝓐 ⊆ Mod(R^op) sometimes corresponds to a duality pair (𝓛, 𝓐). We study the weak global and finitistic dimensions that come with the class 𝓖𝓕_{(𝓕(R),𝓐)} and show that over a (𝓛, 𝓐)-Gorenstein ring, the functor - ⊗_R - is left balanced over Mod(R^op) × Mod(R) by the classes 𝓖𝓕_{(𝓕(R^op),𝓐)} × 𝓖𝓕_{(𝓕(R),𝓐)}. When the duality pair is (𝓕(R), 𝓕𝓟Inj(R^op)) we recover the G. Yang's result over a Ding-Chen ring, and we see that is new for (Lev(R), AC(R^op)) among others.

Synthesis of lithium aluminate by thermal decomposition of a lithium dawsonite-type precursor

J. Jiménez-Becerril,I. García-Sosa 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.1

Of all ceramic materials, lithium aluminate has been widely studied and has become a good candidate to be used as both a fusion blanket and as a matrix in molten carbonate fuel cells. On behalf of these lithium aluminate applications, a variety of procedures has been proven to prepare adequate crystalline and pure material. In this study, lithium aluminate was synthesized by thermally decomposing a lithium dawsonite-type precursor using aluminum nitrate and chloride as a starting material. The lithium aluminate was characterized by scanning electron microscopy (SEM) and X-ray diffraction. According to the results the crystalline form, in mixtures of several phases, of the lithium aluminate obtained depends strongly on the thermal treatment.

Canción de tumba de Julián Herbert

Ivonne Sanchez Becerril 부산외국어대학교 중남미지역원 2013 이베로아메리카 Vol.15 No.1

The effect of the calcination temperature of boehmite on its Co(II) adsorption properties

F. Granados-Correa,J. Jiménez-Becerril 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.2

The effect of the calcination temperature treatment of boehmite over its adsorption ability of Co(II) is presented. The materials obtained were characterized through their crystal structure, morphology, specific surface area, surface hydroxyl group content, and Co(II) adsorption at room temperature. It was found that a maximum cobalt adsorption capacity of 1.6634× 10−3 meq Co2+.g-1 in boehmite calcined at 673 K, which showed the highest values of specific surface area and surface hydroxyl group content compared with the other boehmite samples. The specific surface area of boehmite samples became narrow when the calcination temperature was increased, and the cobalt ion adsorption onto boehmite depends on the specific surface area, but it depends mainly on the transition state of alumina because hydroxyl groups are regenerated on the surface of boehmite when the material is suspended in water; therefore, the calcined boehmite is suitable for cobalt adsorption.

Mechanism of the Hypoglycemic Activity and Hepatoprotective Effect of the Aqueous Extract of Cecropia obtusifolia Bertol

Marıa de los Angeles Fortis-Barrera,Francisco Javier Alarcon-Aguilar,Araceli Becerril-Garcıa,Jose Luis Eduardo Flores-Saenz,Julio Cesar Almanza-Perez,Mario Garcıa-Lorenzana,Roberto Carlos Lazzarini-Le 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.7

In Central and South American traditional medicine, people use Cecropia obtusifolia Bertol (Cecropiaceae) for the treatment of diabetes mellitus. However, its hypoglycemic action mechanism at pancreatic and liver level has been poorly explored. The present research aimed to establish the influence of the aqueous extract of C. obtusifolia, standardized in its content of chlorogenic acid, on insulin secretion in RINm5F cells and over the liver carbohydrates and lipids metabolism, and to determine concomitantly its hepatoprotective effect on mice with streptozotocin-induced diabetes. In RINm5F cells, concentrations 5, 50, 100, and 200 μg/mL of aqueous extract of C. obtusifolia were used to determine [Ca2+]i and insulin secretion. In an acute study, the extract was administered at doses of 500 mg/kg. In another test (subacute), the extract was daily administrated to diabetic mice (200 mg/kg/day) for 30 days. Blood glucose levels and other biochemical parameters were determined, and a liver histological analysis was performed. In RINm5F cells, C. obtusifolia increased [Ca2+]i and insulin secretion, whereas in diabetic mice exhibited acute and subacute hypoglycemic effects. Daily administration of C. obtusifolia to diabetic mice also increased liver glycogen storage and glycogen synthase levels, without apparent changes in gluconeogenesis. Besides, it increased peroxisome proliferator-activated receptor-α (PPAR-α) and long-chain-fatty-acid-CoA ligase 1 (ACSL-1) expression and reduced triglycerides, transaminases (alanine aminotransferase and aspartate aminotransferase), and collagen fibers, modifying anti-inflammatory (adiponectin and interleukin-10) and inflammatory (tumor necrosis factor-α) cytokines in serum. Therefore, the hypoglycemic effect of C. obtusifolia implicates a dual action, promoting insulin secretion, liver glycogen accumulation, and hepatoprotection by decreasing collagen fibers and inflammatory markers, whereas it improves lipid metabolism, due in part to PPAR-α.

TiO2, Al2O3 and SiO2 as radiocatalyst ceramics.

J. C. González-Juárez,H. Carrasco-Ábrego,J. Jiménez-Becerril 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.4

A simple experiment of gamma irradiated radiolytic versus radiocatalytic 4-chlorophenol degradation is presented. Samples of 4-chlorophenol solutions were put in contact with TiO2, Al2O3 and SiO2 ceramics and gamma irradiated. It was found that addition of these materials improve the degradation in a way similar to photocatalysis. A simple experiment of gamma irradiated radiolytic versus radiocatalytic 4-chlorophenol degradation is presented. Samples of 4-chlorophenol solutions were put in contact with TiO2, Al2O3 and SiO2 ceramics and gamma irradiated. It was found that addition of these materials improve the degradation in a way similar to photocatalysis.

Synthesis and characterization of TiO2, CeO2, and TiO2-CeO2 particles forapplication in the treatment of phenol

Y. Lara-López,G. García-Rosales,J. Jiménez-Becerril 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.1

In this work, titanium oxide particles were synthesized (TiO2) by the sol-gel technique, yielding spherical particles with anaverage diameter of 55 nm and surface area of 50.6 m2/g. The material’s major crystallographic phase is rutile. The CeO2particles synthesized in this work present a spherical morphology of 40 nm with a specific surface area of 43.6 m2/g andrepresent the cerianite crystalline phase. In addition, by means of this synthesis technique, particles composed of TiO2 andceria CeO2 that have an average diameter were not affected by the presence of CeO2. However, the specific area (81 m2/g)significantly increased. Strangely, in the composite material, the predominant phase occurred due to the presence of CeO2,which prevents the growth of rutile crystals. The phenol degradation tests showed that at an initial concentration of 30 mg/L, TiO2 degrades in approximately 20% of phenol after 120 minutes, but at an initial concentration of 50 mg/L, degrades atapproximately 15% after 180 minutes. The other synthesized materials reach degradation of only around 3% in both phenolconcentrations.

Synthesis of CuIn_1-xGa_xSe₂ Nanoparticles by Thermal Decomposition Method with Tunable Ga Content

Latha, M.,Devi, R. Aruna,Velumani, S.,Oza, Goldie,Reyes-Figueroa, P.,Rohini, M.,Becerril-Juarez, I. G.,Yi, Junsin American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.11

<P>Chalcopyrite CuIn1-xGaxSe2 (CIGS) nanoparticles were synthesized by mixing copper (I) chloride (CuCl), Indium (III) chloride (InCl3), gallium (III) chloride (GaCl3) and selenium (Se) in oleylamine (OLA) at 260 degrees C for 4 h under nitrogen atmosphere. The Ga/(In + Ga) ratio was tuned across the entire stoichiometric range from 0 to 1. X-ray diffraction analysis (XRD) revealed chalcopyrite crystal structure for samples prepared with x = 0, 0.3, 0.5, 0.7 and 1. The lattice parameters a and c decreased linearly with increasing Ga concentration which is consistent with Vegard's law. Raman spectra exhibited A(1) optical phonon vibrational mode for synthesized nanoparticles which gradually shifted to higher wavenumber with increasing Ga content. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images showed irregular as well as hexagonal plate like morphologies in the size range of 100 to 400 nm. High-resolution transmission electron microscopy (HR-TEM) images showed well-defined lattice fringes and d-spacing correspond to (112) plane which gradually decreases with increasing Ga content. The material compositions of synthesized CIGS nanoparticles with x = 0, 0.3, 0.5, 0.7 and 1 were very close to the desired stoichiometry which was confirmed by energy dispersive X-ray analysis (EDAX). Ultra-violet visible near infrared (UV-VIS-NIR) absorption spectra of the synthesized CIGS nanoparticles revealed that the bandgap could be tuned over the range 1 to 1.7 eV by varying the Ga/(In+Ga) ratio.</P>

Liquid-Crystalline Semiconducting Copolymers with Intramolecular Donor−Acceptor Building Blocks for High-Stability Polymer Transistors

Kim, Do Hwan,Lee, Bang-Lin,Moon, Hyunsik,Kang, Hee Min,Jeong, Eun Jeong,Park, Jeong-Il,Han, Kuk-Min,Lee, Sangyoon,Yoo, Byung Wook,Koo, Bon Won,Kim, Joo Young,Lee, Wi Hyoung,Cho, Kilwon,Becerril, Hecto American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.17

<P>The ability to control the molecular organization of electronically active liquid-crystalline polymer semiconductors on surfaces provides opportunities to develop easy-to-process yet highly ordered supramolecular systems and, in particular, to optimize their electrical and environmental reliability in applications in the field of large-area printed electronics and photovoltaics. Understanding the relationship between liquid-crystalline nanostructure and electrical stability on appropriate molecular surfaces is the key to enhancing the performance of organic field-effect transistors (OFETs) to a degree comparable to that of amorphous silicon (a-Si). Here, we report a novel donor-acceptor type liquid-crystalline semiconducting copolymer, poly(didodecylquaterthiophene-alt-didodecylbithiazole), which contains both electron-donating quaterthiophene and electron-accepting 5,5'-bithiazole units. This copolymer exhibits excellent electrical characteristics such as field-effect mobilities as high as 0.33 cm(2)/V.s and good bias-stress stability comparable to that of amorphous silicon (a-Si). Liquid-crystalline thin films with structural anisotropy form spontaneously through self-organization of individual polymer chains as a result of intermolecular interactions in the liquid-crystalline mesophase. These thin films adopt preferential well-ordered intermolecular pi-pi stacking parallel to the substrate surface. This bottom-up assembly of the liquid-crystalline semiconducting copolymer enables facile fabrication of highly ordered channel layers with remarkable electrical stability.</P>