This paper proposes a new active-neutral-point clamped (ANPC) seven-level inverter based on switched-capacitor technique. The proposed seven-level inverter employs only nine switches and one floating ...capacitor. With the input amplitude of <inline-formula> <tex-math notation="LaTeX">V_{\mathrm {DC}} </tex-math></inline-formula>, the peak output of the proposed topology can reach <inline-formula> <tex-math notation="LaTeX">1.5V_{\mathrm {DC}} </tex-math></inline-formula>. Its boost ability indicates a wider range of output compared with other APNC converters. Needless for auxiliary control methods, the voltages of capacitors in dc link can naturally maintain at <inline-formula> <tex-math notation="LaTeX">0.5V_{\mathrm {DC}} </tex-math></inline-formula>, and the floating capacitor can get self-balance at <inline-formula> <tex-math notation="LaTeX">V_{\mathrm {DC}} </tex-math></inline-formula>. The mechanism of natural balance for capacitors and the operation principle of the proposed topology are described in detail. The merits of the proposed topology on reduced components, lower overall voltage stress, natural balance, and boost ability are also demonstrated through the comparison against the latest similar topologies, showing its suitability for distributed generation, electric vehicle, and other applications. Definitively, the simulation and experimental prototype are implemented to verify the feasibility and performance of the proposed topology. The voltage balance of capacitors has been fully demonstrated through multiple transient experiments.
Plant nucleotide-binding and leucine-rich repeat (NLR) receptors recognize avirulence effectors directly through their integrated domains (IDs) or indirectly via the effector-targeted proteins. ...Previous studies have succeeded in generating designer NLR receptors with new recognition profiles by engineering IDs or targeted proteins based on prior knowledge of their interactions with the effectors. However, it is yet a challenge to design a new plant receptor capable of recognizing effectors that function by unknown mechanisms. Several rice NLR immune receptors, including RGA5, possess an integrated heavy metal-associated (HMA) domain that recognizes corresponding
Avrs and ToxB-like (MAX) effectors in the rice blast fungus. Here, we report a designer rice NLR receptor RGA5
carrying an engineered, integrated HMA domain (RGA5-HMA2) that can recognize the noncorresponding MAX effector AvrPib and confers the RGA4-dependent resistance to the
isolates expressing AvrPib, which originally triggers the Pib-mediated blast resistance via unknown mechanisms. The RGA5-HMA2 domain is contrived based on the high structural similarity of AvrPib with two MAX effectors, AVR-Pia and AVR1-CO39, recognized by cognate RGA5-HMA, the binding interface between AVR1-CO39 and RGA5-HMA, and the distinct surface charge of AvrPib and RAG5-HMA. This work demonstrates that rice NLR receptors with the HMA domain can be engineered to confer resistance to the
isolates noncorresponding but structurally similar MAX effectors, which manifest cognate NLR receptor-mediated resistance with unknown mechanisms. Our study also provides a practical approach for developing rice multilines and broad race spectrum-resistant cultivars by introducing a series of engineered NLR receptors.
Exposure to and the related burden of diseases caused by pollution from solid fuel cooking, known as household air pollution (HAP), has been incorporated in the assessment of the Global Burden of ...Diseases (GBD) project. In contrast, HAP from space heating using solid fuels, prevalent in countries at middle or high altitudes, is less studied and missing from the GBD assessment. China is an ideal example to estimate the bias of exposure and burden of diseases assessment when space heating is neglected, considering its remarkably changing demands for heating from the north to the south and a large solid-fuel-dependent rural population. In this study, based on a meta-analysis of 27 field measurement studies in rural China, we derive the indoor PM2.5 (fine particulate matter with an aerodynamic diameter smaller than 2.5 μm) concentration for both the heating and non-heating seasons. Combining this dataset with time-activity patterns and percentage of households using solid fuels, we assess the population-weighted annual mean exposure to PM2.5 (PWE) and the health impacts associated with HAP in mainland rural China by county for the year 2010. We find that ignoring heating impacts leads to an underestimation in PWE estimates by 38 μg/m3 for the nationwide rural population (16 to 40 as interquartile range) with substantial negative bias in northern provinces. Correspondingly, premature deaths and disability-adjusted life years will be underestimated by approximately 30 × 103 and 60 × 104 in 2010, respectively. Our study poses the need for incorporating heating effects into HAP risk assessments in China as well as globally.
•Space heating contributes significantly to household air pollution in rural China.•Population exposure would be underestimated by ~40 μg/m3 for Chinese rural residents if neglecting space heating impacts.•Premature deaths and disability-adjusted life years would be underestimated by ~30,000 and 600,000 in 2010, respectively.•Considering health impacts of space heating is crucial for household air pollution mitigation, especially in northern China.
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•The Langmuir–Freundlich model is more suitable for methane on activated carbons.•Methane adsorption amount is deeply affected by temperature lower than 313.15 K.•Activated carbon ...affinity on methane is much larger than the raw coal.•Methane adsorption is nonspontaneous and exothermic physisorption at high pressure.•Intermolecular interactions appeared when methane adsorption amount reaches 3 mmol/g.
In this work, three different activated carbons were prepared from low-rank bituminous coal by KOH activation method. High-pressure methane adsorption tests were conducted to these three different activated carbons from 273.15 to 373.15 K. Experimental results show that 313.15 K seems to be the critical temperature point for methane adsorption. When the adsorption temperature is lower than 313.15 K, methane adsorption amount would be rapidly decreased with the increase of temperature. The maximum-monolayer adsorption capacity qm, which is fitted by adsorption experimental result of activated carbon, would be gradually decreased with the increase of temperature. The adsorption equilibrium constant b also presents the similar law as the temperature changes. Thermodynamic parameters show that methane adsorption on activated carbons are nonspontaneous (ΔG° > 0) and exothermic (ΔH° < 0) physisorption (the magnitude of ΔH° < 20 kJ/mol) under high-pressure conditions. And, with increase of temperature, the adsorption feasibility would be decreased. The isosteric heat of adsorption (qst) of methane on the activated carbons are 15.78–16.72 kJ/mol, 15.94–18.26 kJ/mol and 15.83–16.97 kJ/mol, respectively. With increase of the adsorption amount, isosteric heat of adsorption present a first decreasing and then increasing rules under the influence of temperature and pressure. The minimum value of qst appears near the adsorption amount of 3 mmol/g. The higher temperature would increase the thermal motion of methane molecules and the higher pressure would increase the density of methane molecules in the fixed space, which would result in the intermolecular interactions of methane that have been ignored are gradually appeared.
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Transparent chemical gas sensors are assembled from a transparent conducting film of hierarchically nanostructured polyaniline (PANI) networks fabricated on a flexible PET substrate, by coating ...silver nanowires (Ag NWs) followed by the in situ polymerization of aniline near the sacrificial Ag NW template. The sensor exhibits enhanced gas sensing performance at room temperature in both sensitivity and selectivity to NH3 compared to pure PANI film.
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Electrochemical gas evolution reactions are now of great importance in energy conversion processes and industries. Key to the improvement of catalytic performance lies the development of efficient ...catalytic electrodes. Besides the exploration of highly active catalysts, the fast removal of the gas products on the electrode surface should be realized because the adhered gas bubbles would block the following catalytic reactions and decrease the efficiency. In this paper, we introduce an ideal structure, a "superaerophobic" surface, to diminish the negative effects caused by the adhered gas bubbles. Several recent works focusing on addressing this issue are presented with the target reactions of hydrogen evolution and oxygen evolution. It is demonstrated that micro/nano-engineering of the catalyst directly on the current collector is a promising approach to minimize the negative effective induced by the gas bubble adhesion. In the last section, we also discuss the promise of this methodology for other energy related systems.
Constructing electrodes with "superaerophobic" surfaces would benefit the gas bubble releasing behavior and result in significantly enhanced electrochemical performance for gas evolution reactions.
Radiation Therapy Oncology Group (RTOG) 0424 was a phase 2 study of a high-risk low-grade glioma (LGG) population who were treated with temozolomide (TMZ) and radiation therapy (RT), and outcomes ...were compared to those of historical controls. This study was designed to detect a 43% increase in median survival time (MST) from 40.5 to 57.9 months and a 20% improvement in 3-year overall survival (OS) rate from 54% to 65% at a 10% significance level (1-sided) and 96% power.
Patients with LGGs with 3 or more risk factors for recurrence (age ≥40 years, astrocytoma histology, bihemispherical tumor, preoperative tumor diameter of ≥6 cm, or a preoperative neurological function status of >1) were treated with RT (54 Gy in 30 fractions) and concurrent and adjuvant TMZ.
From 2005 to 2009, 129 evaluable patients (75 males and 54 females) were accrued. Median age was 49 years; 91% had a Zubrod score of 0 or 1; and 69%, 25%, and 6% of patients had 3, 4, and 5 risk factors, respectively. Patients had median and minimum follow-up examinations of 4.1 years and 3 years, respectively. The 3-year OS rate was 73.1% (95% confidence interval: 65.3%-80.8%), which was significantly improved compared to that of prespecified historical control values (P<.001). Median survival time has not yet been reached. Three-year progression-free survival was 59.2%. Grades 3 and 4 adverse events occurred in 43% and 10% of patients, respectively. One patient died of herpes encephalitis.
The 3-year OS rate of 73.1% for RTOG 0424 high-risk LGG patients is higher than that reported for historical controls (P<.001) and the study-hypothesized rate of 65%.
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Different types of treatment methods for anode materials are reported to enhance power production in microbial fuel cells (MFCs). Here we report a simple, cost-effective and environmentally friendly ...electrochemical oxidation technique that is used to modify the carbon cloth for the improvement of MFC performance. Carbon cloth is immersed in a 5% NH4HCO3 solution and then the solution is oxidized at different set currents. Optimal performance is obtained at 14 mA cm−2 with an oxidation time of 2 min, based on production of a maximum power density of 939 ± 7 mW m−2 in MFC tests, which is 14.2% higher than that of the untreated carbon cloth control. This treatment method increases the electrochemical active surface area by 2.9 times (from 11.2 to 44.1 cm2), and improves the exchange current density by 41% (from 4.79 × 10−4 to 6.76 × 10−4 A m−2). XPS analysis indicates that electrochemical oxidation in this solution introduced amide groups onto the electrode surface, which likely improves bacterial adsorption and current production. These results show that simple electrochemical treatment method can increase active surface area and alter carbon cloth anodes in ways that increase power production of the MFC.
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•A convenient electrochemical oxidation method for anodic modification of MFC.•EASA and exchange current density were enhanced by 2.9 times and 41%.•Amide and nitrogen functional groups were introduced by the anode modification.•Electron transfer efficiency and power output were dramatically enhanced.
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Knowledge of the contribution that individual countries have made to global radiative forcing is important to the implementation of the agreement on "common but differentiated responsibilities" ...reached by the United Nations Framework Convention on Climate Change. Over the past three decades, China has experienced rapid economic development, accompanied by increased emission of greenhouse gases, ozone precursors and aerosols, but the magnitude of the associated radiative forcing has remained unclear. Here we use a global coupled biogeochemistry-climate model and a chemistry and transport model to quantify China's present-day contribution to global radiative forcing due to well-mixed greenhouse gases, short-lived atmospheric climate forcers and land-use-induced regional surface albedo changes. We find that China contributes 10% ± 4% of the current global radiative forcing. China's relative contribution to the positive (warming) component of global radiative forcing, mainly induced by well-mixed greenhouse gases and black carbon aerosols, is 12% ± 2%. Its relative contribution to the negative (cooling) component is 15% ± 6%, dominated by the effect of sulfate and nitrate aerosols. China's strongest contributions are 0.16 ± 0.02 watts per square metre for CO2 from fossil fuel burning, 0.13 ± 0.05 watts per square metre for CH4, -0.11 ± 0.05 watts per square metre for sulfate aerosols, and 0.09 ± 0.06 watts per square metre for black carbon aerosols. China's eventual goal of improving air quality will result in changes in radiative forcing in the coming years: a reduction of sulfur dioxide emissions would drive a faster future warming, unless offset by larger reductions of radiative forcing from well-mixed greenhouse gases and black carbon.
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Present researches show that aluminum powders with different size show various behaviors. With the increasing of aluminum particle size, reaction rate are greatly reduced and characteristic ...temperatures are slightly increased, but the melting point of particles seems unaffected by the particle sizes. Surface oxidation of aluminum under lower temperature conditions is controlled by the diffusion resistance of oxygen through the alumina shell. However, under higher temperature conditions, particle burning is mainly controlled by the chemical reaction kinetics. Aluminum dust explosion parameters are positively related to their burning rate. However, the explosion parameters are negatively related to the ignition temperature and maximum burning rate temperature. Aluminum dust with particle size less than 5 μm and dust concentrations among 400 g/m3 to 800 g/m3 would be presenting higher explosion severity. Under lower explosion pressures conditions, γ-Al2O3 was produced. However, α-Al2O3 would be produced only under high explosion pressure condition.
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•Aluminum powders with different size show various thermal behaviors.•Aluminum particle oxidation reaction is controlled by different kinetics at different stages.•Crystal phase of Al2O3 can be used to identify the explosion severity.•Thermal behavior parameters can be used as an index to evaluate aluminum dust/air explosion severity.
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