Growth of Nitrogen-Doped MgxZn1−xO for Use in Visible Rejection Photodetectors

A. Nakamura,T. Aoshima,T. Hayashi,S. Gangil,J. Temmyo,A. Navarro,J. Pereiro,E. Munoz 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Improvement in the Schottky behavior of metal (Au) contacts with Mg0.01Zn0.99O and Mg0.01Zn0.99O:N thin films were observed by treating the films with hydrogen peroxide (H2O2) (dipping of samples in H2O2 at 100 ℃ for 3 min). Contacts formed on untreated film showed Ohmic behavior in the current-voltage (I-V ) measurements. The H2O2 treatment led to a smooth surface morphology for the films and resulted in Schottky contact of Au fabricated on the treated films with barrier heights of 0.82 ∽ 0.85 eV. The absolute current density at a reverse bias of 3 V was 1 ∽ 6 × 10−6 A/cm2 for Au contacts on H2O2-treated films. The treated films showed lower electron concentration than the untreated films due to removal of the relatively high conducting top layers of the thin films. A metal-semiconductor-metal (MSM) detector was fabricated using a Mg0.05Zn0.95O:N film and was characterized for its spectral response.

Electro-Oxidation in Combination with Biological Processes for Removal of Persistent Pollutants in Wastewater: A Review

Navarro-Franco, Javier A.,Garzon-Zuniga, Marco A.,Drogui, Patrick,Buelna, Gerardo,Gortares-Moroyoqui, Pablo,Barragan-Huerta, Blanca E.,Vigueras-Cortes, Juan M. The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.1

Persistent organic pollutants (POPs) and emerging pollutants (EP) are characterized by their difficulty to be removed through biological oxidation processes (BOPs); they persist in the environment and could have adverse effects on the aquatic ecosystem and human health. The electro-oxidation (EO) process has been successfully used as an alternative technique to oxidize many kinds of the aforementioned pollutants in wastewater. However, the EO process has been criticized for its high energy consumption cost and its potential generation of by-products. In order to decrease these drawbacks, its combination with biological oxidation processes has been reported as a solution to reduce costs and to reach high rates of recalcitrant pollutants removal from wastewaters. Thus, the location of EO in the treatment line is an important decision to make, since this decision affects the formation of by-products and biodegradability enhancement. This paper reviews the advantages and disadvantages of EO as a pre and post-treatment in combination with BOPs. A perspective of the EO scale-up is also presented, where hydrodynamics and the relationship of A/V (area of the electrode/working volume of the electrochemical cell) experiments are examined and discussed.

New bioactive aromatic compounds from Vismia guianensis

Seo, Eun-Kyoung,Wani, Mansukh C.,Wall, Monroe E.,Navarro, Hernan,Mukherjee, Rabindranath,Farnsworth, Norman R.,Kinghorn, A. Douglas 梨花女子大學校 藥學硏究所 2000 藥學硏究論文集 Vol.- No.9

Five benzophenones, vismiaguianones A-E, and two benzocoumarins, vismiaguianins A and B were isolated from the CHCl_3 extract of the roots of Vismia guianensis by bioassay-directcd fractionation using the DNA strand-scission assay and KB cell line. Of the isolates obtained, vismiaguianone B exhibited DNA strand-scission activity, whereas vismiaguianones D and E and vismiaguianin A were found to be significantly cytotoxic.

Cytotoxic Prenylated Xanthones and the Unusual Compounds Anthraquinobenzophenones from Cratoxylum sumatranum

Seo, Eun-Kyoung,Kim, Nam-Cheol,Wani, Mansukh C.,Wall, Monroe E.,Navarro, Herna'n A.,Burgess, Jason P.,Kazuko, Kawanishi,Kardono, Leonardus B.S.,Riswan, Soedarsono,Rose, William C.,Fairchild, Craig R. 梨花女子大學校 藥學硏究所 2002 藥學硏究論文集 Vol.- No.11

Six new xanthones, cratoxyarborenones A-F (1-6), were isolated from the leaves, twigs, and/or stembark of Cratosylum sumatranum along with the known compound, vismione B (9), as active constituentsby tioasbay-directed fraetionation using the KB human cancer cell line Wtotoxicity assay. In addition,two novel anthraquinobenzophenones, cratoxyarborequinones A (7) and B (8), and two Imown compounds,2,4,0-trihydroxybenzophenone 4-O-geranyl ether and δ-tocotrienol, were obtained as inactive constituents.

A non-dimensional theoretical approach to model high-velocity impact on thick woven plates

L. Alonso,D. Garcia-Gonzalez,C. Navarro,S.K. García-Castillo 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.6

A theoretical energy-based model to capture the mechanical response of thick woven composite laminates, which are used in such applications as maritime or aerospace, to high-velocity impact was developed. The dependences of the impact phenomenon on material and geometrical parameters were analysed making use of the Vaschy-Buckingham Theorem to provide a non-dimensional framework. The model was divided in three different stages splitting the physical interpretation of the perforation process: a first where different dissipative mechanisms such as compression or shear plugging were considered, a second where a transference of linear momentum was assumed and a third where only friction took place. The model was validated against experimental data along with a 3D finite element model. The numerical simulations were used to validate some of the new hypotheses assumed in the theoretical model to provide a more accurate explanation of the phenomena taking place during a high-velocity impact.

High performance low power CMOS dynamic logic for arithmetic circuits

Navarro-Botello, V.,Montiel-Nelson, J.A.,Nooshabadi, S. Elsevier 2007 Microelectronics Journal Vol.38 No.4

This paper presents the design of high performance and low power arithmetic circuits using a new CMOS dynamic logic family, and analyzes its sensitivity against technology parameters for practical applications. The proposed dynamic logic family allows for a partial evaluation in a computational block before its input signals are valid, and quickly performs a final evaluation as soon as the inputs arrive. The proposed dynamic logic family is well suited to arithmetic circuits where the critical path is made of a large cascade of inverting gates. Furthermore, circuits based on the proposed concept perform better in high fanout and high switching frequencies due to both lower delay and dynamic power consumption. Experimental results, for practical circuits, demonstrate that low power feature of the propose dynamic logic provides for smaller propagation time delay (3.5 times), lower energy consumption (55%), and similar combined delay, power consumption and active area product (only 8% higher), while exhibiting lower sensitivity to power supply, temperature, capacitive load and process variations than the dynamic domino CMOS technologies.

Addition of hydrochloric acid to collection bags or collection containers did not change basal endogenous losses or ileal digestibility of amino acid in corn, soybean meal, or wheat middlings fed to growing pigs

Lee, Su A,Blavi, Laia,Navarro, Diego M.D.L.,Stein, Hans H. Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.10

Objective: The hypothesis was that apparent ileal digestibility (AID), basal endogenous losses, and standardized ileal digestibility (SID) of amino acids (AA) are not affected by adding acid to collection containers or bags used to collect ileal digesta from pigs. Methods: Twenty-four growing barrows (initial body weight: 77.8±4.5 kg) that were fitted with a T-cannula in the distal ileum were fed diets for three 7-d periods. An N-free diet and 3 diets containing corn, soybean meal, or wheat middlings as the sole source of AA were used. Within each period, each of the 4 diets were fed to 6 pigs. Among the 6 pigs, digesta from 3 pigs were collected in bags containing no HCl, whereas 40 mL of 3 N HCl was included in the bags used to collect digesta from the remaining 3 pigs. Every other bag collected from each pig was emptied into a container without adding HCl, whereas the remaining bags were added to a container along with 40 mL of 3 N HCl for each bag. All digesta were stored at -20℃ immediately after collection. Data were analyzed using a model that included feed ingredient, HCl in bags, HCl in containers, and all 2-way and 3-way interactions as fixed effects. No 3-way interactions were significant, and data were, therefore, reanalyzed independently for each diet as a 2×2 factorial. Results: There were no interactions between adding HCl to collection bags and to containers, and no effects of adding HCl to collection bags or containers for AID, basal endogenous losses, or SID of most AA were observed. Conclusion: It is not necessary to add acid to digesta collection bags or collection containers if ileal digesta are stored at -20℃ immediately after collection.

Bitumen modification with reactive and non-reactive (virgin and recycled) polymers: A comparative analysis

F.J. Navarro,P. Partal,M. Garcıa-Morales,M.J. Martı´n-Alfonso,F. Martınez-Boza,C. Gallegos,J.C.M. Bordado,A.C. Diogo 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.4

The main goal of this research was to compare the modification capability of two different types of bitumen modifiers: non-reactive plastomers and elastomers, and reactive polymers. The group of nonreactive polymers included a block copolymer (SBS), recycled thermoplastic polymers (EVA/LDPE blends), and crumb tire rubber, which were mixed at a processing temperature of 180 8C. In the second group, a reactive MDI–PEG prepolymer, a low processing temperature modifier (90 8C), was considered. The study was mainly focused on the characterization of the thermorheological behaviour of selected modified bitumen samples. In addition, the thermal behaviour (bymodulated DSC), andmorphology (by optical microscopy) of these modified bitumen samples were also evaluated. All of these bitumen modifiers significantly improve the thermomechanical properties of the resulting binder, especially at high in-service temperatures. However, whereas bitumen modified by non-reactive polymers undergo marked oxidation events due to the high processing temperature used (180℃), MDI–PEG modified bitumen does not experience this phenomenon because of the lower processing temperature involved (90℃). In general, non-reactive polymers should be added in much larger concentrations than the reactive polymer to obtain similar results, although the latter requires a further period of curing, at room temperature, to induce suitable modification. Finally, only MDI–PEG modified bitumen is stable when stored at high temperature (163℃), whereas all the non-reactive polymer-modified bitumen studied undergo either phase separation or particle precipitation.

Submucosal fat accumulation in Crohn’s disease: evaluation with sonography

( Tomás Ripollés ),( María Jesús Martínez-pérez ),( José María Paredes ),( José Vizuete ),( Gregorio Martin ),( Lidia Navarro ) 대한장연구학회 2023 Intestinal Research Vol.21 No.3

Background/Aims: The study objective is to investigate the ultrasound features that allow suspecting the presence of submucosal fat deposition, called the fat halo sign (FHS), in the intestinal wall of patients with Crohn’s disease. Methods: Computed tomography (CT) examinations over a period of 10 years were reviewed for the presence of the FHS in the bowel wall. A measurement of less than -10 Hounsfield units was regarded as indicative of fat. We included only patients who had undergone ultrasound examinations 3 months before or after CT. The study cohort group comprised 68 patients. Wall and submucosal thickness were measured on longitudinal ultrasound sections. A receiver operating characteristic curve was constructed to determine the best cutoff of ultrasound submucosal wall thickness value for predicting FHS in the bowel wall determined on CT. Results: The FHS was present in 22 patients (31%) on CT. There were significant differences between submucosal thickness of patients with FHS and patients without FHS (4.19 mm vs. 2.41 mm). From the receiver operating characteristic curve, a threshold value of 3.1 mm of submucosal thickness had the best sensitivity and specificity to suspect FHS (95.5% and 89.1%, respectively; area under the curve, 0.962), with an odds ratio of 172. All of 16 patients with a submucosal thickness >3.9 mm had FHS. Conclusions: FHS in patients with Crohn’s disease can be suspected on ultrasound in cases with marked thickening of the submucosa layer. In these cases, the activity of the disease should be measured by other parameters such as the color Doppler. (Intest Res 2023;21:385-391)

Experimental determination of the resistance of a single-axis solar tracker to torsional galloping

Eva Martínez-García,Eduardo Blanco Marigorta,Jorge Parrondo Gayo,Antonio Navarro-Manso 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

One of the most efficient designs of solar trackers for photovoltaic panels is the single-axis tracker, which holds the panels along a torque tube that is driven by a motor at the central section. These trackers have evolved to become extremely slender structures due to mechanical optimization against static load and the need of cost reduction in a very competitive market. Owing to the corresponding decrease in mechanical resistance, some of these trackers have suffered aeroelastic instability even at moderate wind speeds, leading to catastrophic failures. In the present work, an analytical and experimental approach has been developed to study that phenomenon. The analytical study has led to identify the dimensionless parameters that govern the motion of the panel-tracker structure. Also, systematic wind tunnel experiments have been carried out on a 3D aeroelastic scale model. The tests have been successful in reproducing the aeroelastic phenomena arising in real-scale cases and have allowed the identification and a close characterization of the phenomenon. The main results have been the determination of the critical velocity for torsional galloping as a function of tilt angle and a calculation methodology for the optimal sizing of solar tracker shafts.