A generalized multilevel inverter based on T-Type switched capacitor module with reduced devices

Conventional multilevel inverters have problems in terms of their complicated expansion and large number of devices. This paper proposes a modular expanded multilevel inverter, which can effectively simplify the expansion and reduce the number of devices. The proposed inverter can ensure the voltage balancing of the voltage-dividing capacitors. The cascading of the T-type switched capacitor module and the step-by-step charging method of the switched capacitors enable the inverter to achieve high output voltage levels and voltage gain. In addition, the inversion can be achieved without the H-bridge, which greatly reduces the total standing voltage of the switches. The nine-level inverter of the proposed topology can be realized with only ten switches, obtaining a voltage gain that is two times larger. The above merits were validated through theoretical analysis and experiments. The proposed inverter has good application prospects in medium- and low-voltage photovoltaic power generation

GeoSegNet: Point Cloud Semantic Segmentation via Geometric Encoder-Decoder Modeling

Semantic segmentation of point clouds, aiming to assign each point a semantic category, is critical to 3D scene understanding.Despite of significant advances in recent years, most of existing methods still suffer from either the object-level misclassification or the boundary-level ambiguity. In this paper, we present a robust semantic segmentation network by deeply exploring the geometry of point clouds, dubbed GeoSegNet. Our GeoSegNet consists of a multi-geometry based encoder and a boundary-guided decoder. In the encoder, we develop a new residual geometry module from multi-geometry perspectives to extract object-level features. In the decoder, we introduce a contrastive boundary learning module to enhance the geometric representation of boundary points. Benefiting from the geometric encoder-decoder modeling, our GeoSegNet can infer the segmentation of objects effectively while making the intersections (boundaries) of two or more objects clear. Experiments show obvious improvements of our method over its competitors in terms of the overall segmentation accuracy and object boundary clearness. Code is available at https://github.com/Chen-yuiyui/GeoSegNet

Towards Control-Centric Representations in Reinforcement Learning from Images

Image-based Reinforcement Learning is a practical yet challenging task. A major hurdle lies in extracting control-centric representations while disregarding irrelevant information. While approaches that follow the bisimulation principle exhibit the potential in learning state representations to address this issue, they still grapple with the limited expressive capacity of latent dynamics and the inadaptability to sparse reward environments. To address these limitations, we introduce ReBis, which aims to capture control-centric information by integrating reward-free control information alongside reward-specific knowledge. ReBis utilizes a transformer architecture to implicitly model the dynamics and incorporates block-wise masking to eliminate spatiotemporal redundancy. Moreover, ReBis combines bisimulation-based loss with asymmetric reconstruction loss to prevent feature collapse in environments with sparse rewards. Empirical studies on two large benchmarks, including Atari games and DeepMind Control Suit, demonstrate that ReBis has superior performance compared to existing methods, proving its effectiveness

Photoluminescence properties of BaxSryLi zSiO4:Ce3+, Mn2+ phosphors for NUV-LED lighting

Conference Name:2011 International Symposium on Advanced Packaging Materials, APM 2011. Conference Address: Xiamen, China. Time:October 25, 2011 - October 28, 2011.A series of Ce3+, Mn2+ codoped BaxSr yLizSiO4:Ce3+, Mn2+ phosphors were synthesized by partially liquid-phase method. The effects of Ba/Sr ratio, Ce/Mn ratio and lithium content on the emission spectra of the BaxSryLizSiO4:Ce3+, Mn2+ (BSLS:Ce, Mn) phosphors were investigated in details, which showed blue emission around 410nm wavelength and red emission at about 620nm wavelength, respectively. With the increasing of Sr/Ba ratio, the color of BSLS:Ce, Mn was changed from orange to red. However, the intensity of blue emission was reduced and red emission was enhanced with an incensement of Mn/Ce ratio. The strongest intensity of emission for the phosphor was obtained at Li content of 15 mol%. ? 2011 IEEE

High Yield and Packing Density Activated Carbon by One-Step Molecular Level Activation of Hydrophilic Pomelo Peel for Supercapacitors

Highly hydrophilic pomelo peel is used as an activated carbon (AC) precursor so that KOH can be homogeneously absorbed within it. Subsequent cryodesiccation retains the original morphology of the pomelo peel and distribution of KOH, which provides the precondition of the one-step molecular level activation. The resulting AC has a high yield of 16.7% of the pomelo peel. The specific surface area of the AC prepared by the one-step molecular activation of cryodesiccated mixture of pomelo peel and KOH (CAC-1) is 1870 m2 g-1, which is higher than that of the AC by the one-step activation of oven-dried mixture (AC-1) and AC by the two-step calcination (AC-2). CAC-1 has the highest specific capacitance of 219 F g-1 at 1 A g-1 among all the three samples. Importantly, the CAC-1 electrode has a high packing density of 0.63 g cm-3. The aqueous supercapacitor based on CAC-1 has a volumetric cell capacitance of 30.7 F cm-3, which corresponds to 123 F cm-3 for a single electrode. When the ionic liquid of 1-ethyl-3-methyl-imidazolium tetrafluoroborate is used as electrolyte, CAC-1 shows maximum specific energy of 40.5 Wh kg-1 and energy density of 25.5 Wh l-1

The roles of sirtuins in ferroptosis

Ferroptosis represents a novel non-apoptotic form of regulated cell death that is driven by iron-dependent lipid peroxidation and plays vital roles in various diseases including cardiovascular diseases, neurodegenerative disorders and cancers. Plenty of iron metabolism-related proteins, regulators of lipid peroxidation, and oxidative stress-related molecules are engaged in ferroptosis and can regulate this complex biological process. Sirtuins have broad functional significance and are targets of many drugs in the clinic. Recently, a growing number of studies have revealed that sirtuins can participate in the occurrence of ferroptosis by affecting many aspects such as redox balance, iron metabolism, and lipid metabolism. This article reviewed the studies on the roles of sirtuins in ferroptosis and the related molecular mechanisms, highlighting valuable targets for the prevention and treatment of ferroptosis-associated diseases

Scale-Up Production of Chicken Myoblasts in Microcarrier-Based System

With the rapid development of the cultivated meat industry, large-scale cell culture technology applied to cultivated meat production has received extensive attention. In this study, two microcarriers, Cytodex 1 and 3D TableTrix™, were used for suspension culture of myoblasts in spinner flasks to select a more suitable one for large-scale culture of myoblasts, and then the effects of different culture conditions on the large-scale culture of cells were explored. The microscopic results showed that Cytodex 1 was spheres with a smooth surface and no macroporous structure, and 3D TableTrix™ was irregular spheres with a porous surface and large pores. The results of cell culture in spinner flasks showed that the cells grew on 3D TableTrix™ more efficiently, and after 10 days of culture, the cell yield was 8.97 × 105 cells/mL. The optimal conditions for cell attachment were intermittent stirring at 40 r/min for 10 min with intervals of 50 min. The best cell culture efficiency was obtained by using cell inoculation density of 1 × 105 cells/mL, microcarrier density of 2 mg/mL, agitation speed of 40 r/min, and initial culture serum concentration of 20% as well as replacing the medium with a new one containing 10% serum (V/V) after 24 h of culture, and replacing 50% of the medium with a new one with every other day. By bead to bead transfer of the microcarriers, the cells were transferred to a 2 L spinner flask. Finally, 1.07 × 109 cells were harvested with a survival rate of more than 95%. Microcarriers loaded with cells could be cryopreserved and resuscitated, and no significant differences in proliferation status and morphology were observed compared with thawed cells. The optimized microcarrier based culture process will have promising applications in the industrial scale production of cultivated meat

Application of the Pipeline Embolization Device for Giant Vertebrobasilar Dissecting Aneurysms in Pediatric Patients

Objective: To evaluate the feasibility and effectiveness of the pipeline embolization device (PED) for the treatment of pediatric giant vertebrobasilar dissecting aneurysms (VBDAs).Methods: We retrospectively reviewed our institutional clinical database and identified 2,706 patients who presented with a diagnosis of intracranial aneurysms from January 2016 to June 2018. Among this group, 153 patients were diagnosed with VBDAs, and 54 of these patients underwent PED therapy. The PED technique was used in four patients who were 18 years old or younger at the time of presentation (two males, two females; mean age 9.25 years; age range 8–11 years).Results: All four included pediatric patients were managed with the PED. One patient (25%) was treated with the PED alone, while three (75%) were treated with the PED and coils. One patient died from brainstem infarction or compression of the brainstem, while follow-up of the other three patients revealed favorable outcomes. The mass effect was reduced in cases 1, 2, and 3 on follow-up MRI performed 6 months after the PED procedure.Conclusions: PEDs could be feasible in the treatment of pediatric giant VBDAs. However, the safety and efficacy of this method have not been clarified in this special pediatric population, and long-term follow-up is still necessary

Research on Technical supervision of Steam turbine in nuclear power plant

Based on the technical characteristics of nuclear power turbine, the technical differences between nuclear power turbine and thermal power turbine are analyzed. Based on the premise of nuclear safety and combined with the characteristics of nuclear power plants, the feasible supervision mechanism of conventional island turbine and the daily management responsibilities of nuclear power supervision are studied. Extensive research and collection of nuclear power related data, including technical specifications, operation procedures, maintenance procedures, etc., through the analysis and collation of these data, the technical supervision content of nuclear power conventional island turbine is studied, highlighting the differences with thermal power turbine technical supervision