10 research outputs found
Complete mitochondrial genome of Dong Tao chicken breed (Gallus gallus domesticus) of Vietnam
The complete mitochondrial genome of Dong Tao chicken breed (Gallus gallus domesticus, Dong Tao) was obtained by PCR and sequencing. The complete mitogenome was 16,783âbp in length, with the nucleotide composition for A, T, C, G was 30.29%, 23.75%, 32.48%, and 13.48%, respectively. The mitogenome of Dong Tao chicken contained a non-coding control region (D-loop), 2 rRNA genes, 13 protein-coding genes, and 22 tRNA genes. Phylogenetic analysis revealed that breed Dong Tao chicken breed was sister-close to G. gallus breed Guangxi, and paraphyletic to G. spadiceus, S. jabouillei, and a range of Chinese indigenous, ie. breeds Rugao and Taoyuan
Ăvaluation de l'alimentation en courant continu pour une distribution d'Ă©nergie efficace dans les appareils domestiques
Currently, there is a drop in the price of distributed energy resources, especially solar PVs, which leads to a significant growth of the installed capacities in many countries. On the other hand, policies encouraging energy efficiency have promoted the development of DC loads in domestic areas, such as LEDs lighting, computers, telephones, televisions, efficient DC motors and electric vehicles. Corresponding to these changes in sources and loads, DC microgrid distribution system becomes more attractive than the traditional AC distribution system. The main advantages of the DC microgrid are higher energy efficiency, easier in integrating with distributed energy sources and storage systems. While many studies concentrate on the control strategies and energy management in the DC microgrid, the protection still receives inadequate attention and lack of regulations and experiences. Protection in DC grids is more complex than AC grids due to the continuous arc, higher short circuit current value and fault rate of rising. Furthermore, the DC distributed grids are composed of many electronic and semiconductor switching devices, which only sustain the fault currents of some tens of microseconds. Mechanical circuit breakers, which have a response time in tens of milliseconds, seem not to meet the safety requirement of DC microgrids. The lack of effective protection devices is a barrier to the development of DC microgrids in the distributed systems. This thesis proposes a self-power solid state DC circuit breaker using normally-on SiC JFET, which offers a great protection device for DC microgrids due to its fast response time and low on-state losses. The design of the solid state DC circuit breaker aims to meet two objectives: fast response time and high reliability. The designed specifications and critical energies that result in the destruction of the circuit breaker are identified on the basis of the experiments of a commercial normally-on JFET. In addition, a very fast and reliable protection driver based on a forward-flyback converter topology is employed to generate a sufficient negative voltage to turn and hold off the SiC JFET. The converter will be activated whenever short-circuit faults are detected by sensing the drain-source voltage, then creating a negative voltage applied to the gate of JFET. To avoid gate failure by overvoltage at the gate of JFET, the output voltage of the forward-flyback converter is regulated using Primary Side Sensing technique. Experimental results validated the working principle of the proposed solid state DC circuit breaker with fault clearing time less than 3 ÎŒs. Additionally, a model of the normally-on JFET in Matlab/Simulink environment is built for exploring the behaviors of the solid-state DC circuit breaker during short-circuit faults. The agreement between the simulation and experimental results confirms that this JFET model can be appropriately used for the investigation of solid state DC circuit breaker operations and DC microgrids in general during fault evens and clearing fault processesActuellement, il y a une baisse du prix des ressources Ă©nergĂ©tiques distribuĂ©es, en particulier l'Ă©nergie solaire photovoltaĂŻque, conduisant Ă la croissance significative de leur capacitĂ© d'installation dans de nombreux pays. D'autre part, les politiques encourageant l'efficacitĂ© Ă©nergĂ©tique ont favorisĂ© le dĂ©veloppement de charges DC dans les zones domestiques, telles que l'Ă©clairage LED, les ordinateurs,, les tĂ©lĂ©phones, les tĂ©lĂ©viseurs, les moteurs DC efficaces et les vĂ©hicules Ă©lectriques. Grace Ă ce changement, le systĂšme de distribution de microgrid DC devient plus attractive que le systĂšme de distribution Ă courant alternatif traditionnel. Les avantages principaux du microgrid DC sont l'efficacitĂ© Ă©nergĂ©tique plus Ă©levĂ©e, plus facile Ă intĂ©grer avec les sources d'Ă©nergie distribuĂ©es et le systĂšme de stockage. Alors que de nombreuses recherches se concentrent sur les stratĂ©gies de contrĂŽle et la gestion de l'Ă©nergie dans le microgrid DC, sa protection reçoit une attention insuffisante et un manque de rĂ©glementation et d'expĂ©riences. La protection dans les rĂ©seaux DC est plus difficile que dans le rĂ©seau AC en raison de l'arc continu, de la valeur plus Ă©levĂ©e du courant de courtcircuit et du taux de dĂ©faut de montĂ©e. En outre, dans les rĂ©seaux distribuĂ©s Ă courant continu sont composĂ©s de nombreux dispositifs de commutation Ă©lectroniques et semi-conducteurs, qui ne supportent le courant de dĂ©faut que quelques dizaines de microsecondes. Les disjoncteurs mĂ©caniques, qui ont un temps de rĂ©ponse de quelques dizaines de millisecondes, ne semblent pas satisfaire aux exigences de sĂ©curitĂ© du microrĂ©seau Ă courant continu. L'absence d'un dispositif de protection efficace constitue un obstacle au dĂ©veloppement du microgrid DC dans le systĂšme distribuĂ©. Cette thĂšse propose un disjoncteur DC auto-alimentĂ© Ă courant continu utilisant normalement JFET SiC, qui offre un excellent dispositif de protection pour les microgrids DC grĂące Ă son temps de rĂ©ponse rapide et ses faibles pertes Ă l'Ă©tat passant. La conception du disjoncteur DC Ă semi-conducteurs vise Ă rĂ©pondre Ă deux objectifs: temps de rĂ©ponse rapide et fiabilitĂ©. Les spĂ©cifications conçues et les Ă©nergies critiques qui entraĂźnent la destruction du disjoncteur sont identifiĂ©es sur la base des rĂ©sultats mesurĂ©s d'un JFET populaire dans le commerce. Un pilote de protection trĂšs rapide et fiable basĂ© sur une topologie Ă convertisseur flyback avant est utilisĂ© pour gĂ©nĂ©rer une tension nĂ©gative suffisante pour tourner et maintenir le JFET SiC. Le convertisseur sera activĂ© chaque fois que le disjoncteur dĂ©tecte des dĂ©fauts de court-circuit en dĂ©tectant la tension de drain-source de JFET et crĂ©e une tension nĂ©gative s'applique Ă la porte de JFET. Pour Ă©viter une dĂ©faillance de la porte par surtension au niveau de la grille du JFET, la tension de sortie du convertisseur de retour vers l'avant est rĂ©gulĂ©e Ă l'aide de la mesure cotĂ© primaire. Les rĂ©sultats expĂ©rimentaux sur le prototype du disjoncteur DC ont validĂ© les principes de fonctionnement proposĂ©s et ont confirmĂ© que le disjoncteur DC Ă semi-conducteurs proposĂ© peut interrompre le dĂ©faut en 3 ÎŒs. D'un autre cĂŽtĂ©, un modĂšle du JFET normalement activĂ© dans l'environnement Matlab/Simulink est construit pour Ă©tudier les comportements du SSCB pendant une durĂ©e de court-circuit. L'accord entre la simulation et les rĂ©sultats expĂ©rimentaux confirment que ce modĂšle JFET peut ĂȘtre utilisĂ© pour simuler le fonctionnement d'un disjoncteur DC et dans l'Ă©tude du fonctionnement du microgrid DC pendant le processus de dĂ©faut et de compensatio
Knowledge, skills and competences for green sustainable energy systems requirement
International audienc
A Control Strategy of DC Building Microgrid Connected to the Neighborhood and AC Power Network
International audienceRecently, the use of DC microgrid distribution system has become more attractive than traditional AC systems due to their energy efficiency and ability to easily integrate with renewable energy sources and batteries. This paper proposes a 500 V DC microgrid which consists of a 20 kWp photovoltaic panel, batteries, and DC loads. A hierarchical control strategy to ensure balance power of the DC microgrid and the maintenance of common DC bus voltage is presented. The capability of exchanging power energy of the microgrid with the power system of neighborhood buildings is also considered. Typical operation modes are simulated in the Matlab/simulink environment to confirm the good performance of the controllers and the efficiency of appropriately controlling the chargeâdischarge of the battery system. This research is expected to bring benefits to the design and operation of the system, such as reducing the capacity of batteries, increasing the self-supply of buildings, and decreasing the electricity demand from the AC grid
Design of a forward-flyback converter based drive with gate voltage limitation for a DC circuit breaker using normally-on SiC JFET
International audienceNormally-on Silicon Carbide (SiC) JFETs are considered promising switching semiconductor devices for solid state DC breaker due to their small on-resistance and robustness with short-circuit. In the self-power DC solid-state circuit breaker using normally-on SiC JFET, a very fast and reliable protection driver is required to generate a sufficient negative voltage to turn and hold off the SiC JFET. This paper proposes a forward-flyback converter topology for the protection driver. The converter will be activated whenever circuit breaker detects short-circuit faults by sensing the drain-source voltage of JFET and create a negative voltage applies to the gate of JFET. To avoid gate failure by over voltage at the gate of JFET, the output voltage of the forward-flyback converter is regulated using Primary Side Sensing technique. Experimental results show that the proposed protection driver can provide sufficient negative output voltage to turn off JFET and maintain this voltage in the permitted range
Simulation of the photovoltaic using Zeta Converter with Battery storage system for lighting at night in decentralised areas
International audienc
Building a Matlab/Simulink Model of a SiC-JFET for the investigation of Solid State DC Breaker
International audienceRecently, solid state DC circuit breaker (SSCB) using normally-on SiC-JFET offers a great protection device for DC microgrid due to its fast response time (in tens of microseconds) and low on-state losses. At the simulation stage, an appropriate model of the SiC-JFET should be built in order to reflect correctly behaviors of the breaker during faults and clearing faults processes. For instance, the fault clearing time should be in tens of microseconds. This paper presents the development of a novel model for commercial normally-on SiC-JFET in solid state circuit breaker application. The parameters of the model are first extracted from the SiC-JFET experimental data. Afterward, the operation of a SiC-JFET in a prototype of solid state breaker is evaluated by comparing the static and dynamic characteristics of SiC-JFET model, which is simulated in Matlab/Simulink, to the experimental measurement. Good agreement between simulation and experiment has been achieved and confirms the validity of the built model of the SiC JFET
Host Genetic Risk Factors Associated with COVID-19 Susceptibility and Severity in Vietnamese
Since the emergence and rapid transmission of SARS-CoV-2, numerous scientific reports have searched for the association of host genetic variants with COVID-19, but the data are mostly acquired from Europe. In the current work, we explored the link between host genes (SARS-CoV-2 entry and immune system related to COVID-19 sensitivity/severity) and ABO blood types with COVID-19 from whole-exome data of 200 COVID-19 patients and 100 controls in Vietnam. The O blood type was found to be a protective factor that weakens the worst outcomes of infected individuals. For SARS-CoV-2 susceptibility, rs2229207 (TC genotype, allele C) and rs17860118 (allele T) of IFNAR2 increased the risk of infection, but rs139940581 (CT genotype, allele T) of SLC6A20 reduced virus sensitivity. For COVID-19 progress, the frequencies of rs4622692 (TG genotype) and rs1048610 (TC genotype) of ADAM17 were significantly higher in the moderate group than in the severe/fatal group. The variant rs12329760 (AA genotype) of TMPRSS2 was significantly associated with asymptomatic/mild symptoms. Additionally, rs2304255 (CT genotype, allele T) of TYK2 and rs2277735 (AG genotype) of DPP9 were associated with severe/fatal outcomes. Studies on different populations will give better insights into the pathogenesis, which is ethnic-dependent, and thus decipher the genetic factor’s contribution to mechanisms that predispose people to being more vulnerable to COVID-19
Rare and novel variants of PRKN
Abstract Background Earlyâonset Parkinson's disease (EOPD) refers to that of patients who have been diagnosed or had onset of motor symptoms before age 50, accounting for 4% of Parkinson's disease patients. The PRKN and PINK1 genes, both involved in a metabolic pathway, are associated with EOPD. Methods To identify variants associated with EOPD, coding region of PARKIN and PINK1 genes in 112 patients and 112 healthy individuals were sequenced. Multiplex ligationâdependent probe amplification kit was used to determine EOPD patients that carried mutations in PRKN and PINK1 genes. Results and Conclusion Three rare and three novel mutations in total of 14 variants of PARKIN and PINK1 were detected in the EOPD cohorts. Mutations of PRKN and PINK1 genes were found in five (4.4%) patients, which were four patients with compound heterozygous variants in the PRKN and one case with a homozygous mutation of the PINK1 gene. The novel mutations might reduce the stability of the PRKN and PINK1 protein molecules. The frequency of homozygous mutant genotype p.A340T of the PINK1 in the EOPD cohort was higher than in control (p = 0.0001, OR = 5.704), suggesting this variant might be a risk factor for EOPD. To the best of our knowledge, this is the first study of PRKN and PINK1 genes conducted on Vietnamese EOPD patients. These results might contribute to the genetic screening of EOPD in Vietnam