http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Modeling of Temperature Dependent Parasitic Gate Turn-On in Silicon IGBTs
R. Bonyadi,O. Alatise,S. Jahdi,J. Ortiz Gonzalez,L. Ran,P. A. Mawby 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
Parasitic turn-on can cause unintentional triggering of the IGBTs since the discharge current of the Miller capacitance coupled with high dV/dt can activate a device that should be off. The short circuit current resulting from parasitic turn-on coupled with the high voltage causes significant power dissipation which can be a reliability issue. This issue is exacerbated by higher ambient temperatures since the negative temperature coefficient of the IGBT’s threshold voltage as well as the positive temperature coefficient of the minority carrier lifetime will increase the peak and duration of the short circuit current. Accurate modeling of the shoot-through power and its temperature dependency is important for circuit designers when designing mitigation techniques like multiple resistive paths and bipolar gate drivers. The physics-based model proposed in this paper can produce accurate results with good matching over temperature. The model improves on compact circuit models based on lumped parameters.
Armesto, Diego,Ortiz, Maria J.,Agarrabeitia, Antonia R. Korean Society of Photoscience 2003 Journal of Photosciences Vol.10 No.1
Recent studies on the photoreactivity of l,4-unsaturated systems have changed some ideas that were firmly established in this area of research for many years. Thus, we have described the first examples of 2-aza-di-$\pi$-methane (2-ADPM) rearrangements promoted by triplet-sensitization and by single electron transfer (SET) using electron-acceptor sensitizers. These reactions afford N-vinylaziridine and cyclopropylimine photoproducts in the first examples of di-$\pi$-methane processes that yield three-membered ring heterocycles. l-Aza-1,4-dienes also undergo SET-promoted l-aza-di-$\pi$-methane (l-ADPM) rearrangements via radical-cation intermediates using electron acceptor sensitizers. In some cases, alternative cyclizations yielding different carbocycles and heterocycles have been observed. The l-ADPM and di-$\pi$-methane (DPM) reactions also occur via radical-anion intermediates on irradiation using electron donor sensitizers. On the other hand, the photoreactivity reported for $\beta$,${\gamma}$-unsaturated aldehydes for many years was decarbonylation to the corresponding alkenes. However, our studies demonstrate that these compounds undergo the oxa-di-$\pi$-methane (ODPM) rearrangement with high chemical and quantum efficiency. A comparison of the photochemical reactivity of $\beta$,${\gamma}$-unsaturated aldehydes and corresponding methyl ketones has shown that the ketones do not undergo the ODPM rearrangement while the corresponding aldehydes are reactive by this pathway. Monosubstituted $\beta$,${\gamma}$-unsaturated aldehydes at C-2 undergo the ODPM rearrangement yielding the corresponding cyclopropane carbaldehydes diastereoselectively. Finally, we have described the first examples of reactions, similar to the well know Norrish Type I process, which take place in the triplet excited state of $\beta$,${\gamma}$-unsaturated carbonyl compounds by excitation of the C-C double bond instead of the carbonyl group.
L Verdiguel-Fernández,R Oropeza-Navarro,Adolfo Ortiz,MG Robles-Pesina,J Ramírez-Lezama,A Castañeda-Ramírez,A Verdugo-Rodríguez 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.4
For control of brucellosis in small ruminants, attenuated B. melitensis Rev1 is used but it can be virulent for animals and human. Based on these aspects, it is essential to identify potential immunogens to avoid these problems in prevention of brucellosis. The majority of OMPs in the Omp25/31 family have been studied because these proteins are relevant in maintaining the integrity of the outer membrane but their implication in the virulence of the different species of this genus is not clearly described. Therefore, in this work we studied the role of Omp31 on virulence by determining the residual virulence and detecting lesions in spleen and testis of mice inoculated with the B. melitensis LVM31 mutant strain. In addition, we evaluated the conferred protection in mice immunized with the mutant strain against the challenge with the B. melitensis Bm133 virulent strain. Our results showed that the mutation of omp31 caused a decrease in splenic colonization without generating apparent lesions or histopathological changes apparent in both organs in comparison with the control strains and that the mutant strain conferred similar protection as the B. melitensis Rev1 vaccine strain against the challenge with B. melitensis Bm133 virulent strain. These results allow us to conclude that Omp31 plays an important role on the virulence of B. melitensis in the murine model, and due to the attenuation shown by the strain, it could be considered a vaccine candidate for the prevention of goat brucellosis.
Analysis of Circular PDMS Microballoons With Ultralarge Deflection for MEMS Design
Sang-Hee Yoon,Reyes-Ortiz, Vimalier,Kwang-Ho Kim,Young Ho Seo,Mofrad, Mohammad R K IEEE 2010 Journal of microelectromechanical systems Vol.19 No.4
<P>This paper presents the simplified analytical and numerical analyses of the ultralarge deflection of circular polydimethylsiloxane (PDMS) microballoons (MBs) under pressure for microelectromechanical systems design. The analytical model assuming spherical symmetry on the deformed shape of MB yields a simplified solution on the pressure-normalized maximum deflection and two in-plane principal strains of the ultralargely deflected MB. The accuracy of the theoretical model is evaluated by comparing against the experimental results. Furthermore, by using a computational analysis that incorporates a Mooney-Rivlin model for a PDMS micromembrane, the properties of the PDMS fabricated at a mixing ratio of 10:1 base to catalyst, a curing temperature of 20°C, and a curing time of 48 h are determined for noncircular PDMS micromembrane analysis. In the experimental study, eight types of PDMS MBs, each of which has a membrane radius of 143, 202, 452, or 904 μm and a membrane thickness of 10 or 20 μm, are characterized in air and in cell culture media. A new strain-measuring method using fluorescent polymer microspheres for the PDMS MB is also introduced. The characterization of the PDMS MBs in air validates our theoretical model and shows an increase in elastic modulus as the membrane thickness decreases. The effect of cell culture media on the membrane rigidity of PDMS is also examined for biological applications of PDMS.</P>
Zouhair Boukha,Jonatan González-Prior,Beatriz de Rivas,Juan R. González-Velasco,Rubén López-Fonseca,José I. Gutiérrez-Ortiz 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-
Hydroxyapatite (HAP) support has been synthesised and impregnated with different amounts of Pd. Theprepared Pd/HAP catalysts have been thoroughly characterised by BET, XRD, TEM, UV–visible–NIR, FTIR,XPS, CO2-TPD and NH3-TPD techniques and tested in the DCE oxidation reaction. The characterisation of the catalysts has revealed a clear evolution of the Pd species structure, byincreasing the Pd content, from highly dispersed tetrahedral coordinated Pd2+ to larger Pd2+ speciesparticles adopting square planar geometry. The latter seems to be partially encapsulated by the HAPsupport. In DCE oxidation reaction the Pd/HAP system has shown an activity comparable to that of conventionalsystem (Pd/alumina). However, the former has proved high selectivity towards the production ofoxygenated products (COx (CO2 and CO)). Notably, in contrast to Pd/alumina, the DCE oxidation does notyield vinyl chloride intermediate product over Pd/HAP. This catalytic behaviour has been related to themoderate acidity of HAP compared to that of alumina together with its interaction with the Pd activephase. This report, then, considers that Pd(x)/HAP could be presented as a good alternative to thosereported in the available literature.
Alvarado-Rosales, D.,Nieto-Lopez, E.H.,Teliz-Ortiz, D.,Ayala-Escobar, V.,Silva-Rojas, H.V.,Nieto-Angel, R.,Leyva-Mir, S.G.,Jimenez-Nieto, A.,Mendez-Inocencio, C. The Korean Society of Plant Pathology 2015 식물병연구 Vol.21 No.3
The tejocote (Crataegus spp.) is a tree considered to be native to Mexico. The aim of this study was to identify the causal agent of tejocote rust in the State of Puebla. Tejocote fruits were sampled in 2012 and 2013. The fungus was studied morphologically using light and scanning electron microscopy and molecularly using phylogenetic analysis of 18S and 28S rDNA genes. The fungus was identified as Gymnosporangium clavipes on tejocote fruits. To our knowledge, this is the first confirmed report of Gymnosporangium clavipes Cooke & Peck affecting Crataegus mexicana var. Chapeado and C. gracilior in Puebla Mexico.
D. Alvarado-Rosales,E. H. Nieto-López,D. Téliz-Ortiz,V. Ayala-Escobar,R. Nieto-Angel,H. V. Silva-Rojas,S. G. Leyva-Mir,A. Jiménez-Nieto,C. Méndez-Inocencio 한국식물병리학회 2015 식물병연구 Vol.21 No.3
The tejocote (Crataegus spp.) is a tree considered to be native to Mexico. The aim of this study was to identify the causal agent of tejocote rust in the State of Puebla. Tejocote fruits were sampled in 2012 and 2013. The fungus was studied morphologically using light and scanning electron microscopy and molecularly using phylogenetic analysis of 18S and 28S rDNA genes. The fungus was identified as Gymnosporangium clavipes on tejocote fruits. To our knowledge, this is the first confirmed report of Gymnosporangium clavipes Cooke & Peck affecting Crataegus mexicana var. Chapeado and C. gracilior in Puebla Mexico.