In this paper the quality of power generated from wind energy conversion system employing a double fed induction generator (DFIG) is investigated. The DFIG performance is tested with 3 types of converters interfacing ...In this paper the quality of power generated from wind energy conversion system employing a double fed induction generator (DFIG) is investigated. The DFIG performance is tested with 3 types of converters interfacing the rotor with the grid. These are: the six-step thyristor inverter with diode rectifier, six-step IGBT inverter with diode rectifier, and 3-level IGBT-PWM inverter with diode rectifier. The harmonics in current and voltage, power factor value, and the transient behavior in each system are investigated and compared. Comparison is done at sub-and super-synchronous DFIG operational speed. In the system with lowest power quality passive filters or LC filter are added and improvement in system performance is recorded. From this study the optimum system from point of view of cost and control complexity is concluded.展开更多
Heart diseases are the main cause of mortality in Mexico, being coronary </span><span style="font-family:Verdana;">heart disease the most frequent in the country. Its high prevalence makes i...Heart diseases are the main cause of mortality in Mexico, being coronary </span><span style="font-family:Verdana;">heart disease the most frequent in the country. Its high prevalence makes important </span><span style="font-family:Verdana;">the study of the pathophysiology and the search for prognostic </span><span style="font-family:Verdana;">factors. Different genes and polymorphisms promote atherogenesis and coronary artery disease, they affect inflammatory and vascular pathological processes. </span><span style="font-family:Verdana;">Interferon regulatory factor 5 (IRF5) is associated with coronary heart disease, it promotes chronic inflammation and cytokines release;it could trigger immune reactions and its activating receptors express in the vascular endothelium. Besides, polymorphisms in the renin-angiotensin-aldosterone system (RAAS) are implied with coronary disease, they are found in angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), and angiotensin-converting enzyme (ACE) genes. These genetic polymorphisms are associated with a prothrombotic state, endothelial dysfunction, and immune activation. Multiple experimental studies showed that chronic activation of RAAS and chronic expression of IRF5 generates an environment prone to the development of atherosclerosis, and autoimmune and cardiovascular diseases. Studying these specific genes and their relationship with coronary heart disease will allow a better understanding of the pathological process and possibly the quest for new treatments.展开更多
Preparation of V2O5 from converter slag （CS） was investigated through roasting, leaching, extracting, and precipitating processes. The corresponding roles of the parameters during every procedure were analyzed in de...Preparation of V2O5 from converter slag （CS） was investigated through roasting, leaching, extracting, and precipitating processes. The corresponding roles of the parameters during every procedure were analyzed in detail. （NH4）2SO4 and KHSO4 were used as fusing agents to transform compounds containing vanadium into soluble species. Mass ratio of （NH4）2SO4 to CS, mass ratio of KHSO4 to CS, and roasting temperature during the roasting process can significantly influence leaching rate of vanadium （LRV）. With H2SO4 as leaching agent, 99.2 % vanadium in CS can be leached out under the optimum leaching conditions, which mainly refer to liquid-to-solid ratio, H2SO4 concentration, leaching temperature, and leaching time. Extracting and back-extracting processes were introduced to purify the vanadium from the H2SO4 lixivium. Extracting rate of vanadium （ERV） greatly depends on iron powder concentration, pH, diisooctyl phosphate （P2O4） content, volume ratio of extractant to H2SO4 lixivium, and extracting time. By adding ammonium hydroxide, 94.0 % vanadium in back-extracting solution can be separated in the form of precipitates. The product from the roasted precipitate mainly consists of V2O5, the content of which is higher than 90.0 %.展开更多
文摘In this paper the quality of power generated from wind energy conversion system employing a double fed induction generator (DFIG) is investigated. The DFIG performance is tested with 3 types of converters interfacing the rotor with the grid. These are: the six-step thyristor inverter with diode rectifier, six-step IGBT inverter with diode rectifier, and 3-level IGBT-PWM inverter with diode rectifier. The harmonics in current and voltage, power factor value, and the transient behavior in each system are investigated and compared. Comparison is done at sub-and super-synchronous DFIG operational speed. In the system with lowest power quality passive filters or LC filter are added and improvement in system performance is recorded. From this study the optimum system from point of view of cost and control complexity is concluded.
文摘Heart diseases are the main cause of mortality in Mexico, being coronary </span><span style="font-family:Verdana;">heart disease the most frequent in the country. Its high prevalence makes important </span><span style="font-family:Verdana;">the study of the pathophysiology and the search for prognostic </span><span style="font-family:Verdana;">factors. Different genes and polymorphisms promote atherogenesis and coronary artery disease, they affect inflammatory and vascular pathological processes. </span><span style="font-family:Verdana;">Interferon regulatory factor 5 (IRF5) is associated with coronary heart disease, it promotes chronic inflammation and cytokines release;it could trigger immune reactions and its activating receptors express in the vascular endothelium. Besides, polymorphisms in the renin-angiotensin-aldosterone system (RAAS) are implied with coronary disease, they are found in angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), and angiotensin-converting enzyme (ACE) genes. These genetic polymorphisms are associated with a prothrombotic state, endothelial dysfunction, and immune activation. Multiple experimental studies showed that chronic activation of RAAS and chronic expression of IRF5 generates an environment prone to the development of atherosclerosis, and autoimmune and cardiovascular diseases. Studying these specific genes and their relationship with coronary heart disease will allow a better understanding of the pathological process and possibly the quest for new treatments.
基金financially supported by the Fundamental Research Fund for the Central Universities (No. N130302004)the National Major International Cooperation Program of China (No. 2012DFR60210)+1 种基金the National High-Tech Research and Development Program of China (No. 2012AA062304)the National Natural Science Foundation of China (Nos. 51090384 and U1360204)
文摘Preparation of V2O5 from converter slag （CS） was investigated through roasting, leaching, extracting, and precipitating processes. The corresponding roles of the parameters during every procedure were analyzed in detail. （NH4）2SO4 and KHSO4 were used as fusing agents to transform compounds containing vanadium into soluble species. Mass ratio of （NH4）2SO4 to CS, mass ratio of KHSO4 to CS, and roasting temperature during the roasting process can significantly influence leaching rate of vanadium （LRV）. With H2SO4 as leaching agent, 99.2 % vanadium in CS can be leached out under the optimum leaching conditions, which mainly refer to liquid-to-solid ratio, H2SO4 concentration, leaching temperature, and leaching time. Extracting and back-extracting processes were introduced to purify the vanadium from the H2SO4 lixivium. Extracting rate of vanadium （ERV） greatly depends on iron powder concentration, pH, diisooctyl phosphate （P2O4） content, volume ratio of extractant to H2SO4 lixivium, and extracting time. By adding ammonium hydroxide, 94.0 % vanadium in back-extracting solution can be separated in the form of precipitates. The product from the roasted precipitate mainly consists of V2O5, the content of which is higher than 90.0 %.
