Input-parallel output-series DC-DC boost converter with a wide input voltage range, for fuel cell vehicles

An input-parallel, output-series DC-DC Boost converter with a wide input voltage range is proposed in this paper. An interleaved structure is adopted in the input side of this converter to reduce input current ripple. Two capacitors are connected in series on the output side to achieve a high voltage-gain. The operating principles and steady-state characteristics of the converter are presented and analyzed in this paper. A 400V/1.6kW prototype has been created which demonstrates that a wide range of voltage-gain can be achieved by this converter and it is shown that the maximum efficiency of the converter is 96.62%, and minimum efficiency is 94.14% The experimental results validate the feasibility of the proposed topology and its suitability for fuel cell vehicles

Anti-endometriotic effect of Angelica sinensis (Oliv.) Diels extract in human endometriotic cells and rats

Purpose: To study the anti-endometriotic effect of Angelica sinensis (Oliv.) Diels extract (ASDE) in human endometriotic cells and rats.Method: Forty female rats were randomly divided into four groups (10 rats/group): control, endometriosis+danazol, endometriosis+high dose of ASDE and low dose of ASDE. The rats were orally administered either vehicle (200 μL of PBS) alone or ASDE (140, 280 and 560 mg/kg/day) for 5 weeks. Danazol was used as the control drug. After induction of endometriosis for 4 weeks, the rats were sacrificed by cervical dislocation and the peritoneum and visceral organs examined visually to measure the number of endometriotic lesions. Serum levels of cancer antigen 125 (CA-125) and interleukin 13 (IL-13), interleukin 18 (IL-18) and tumor necrosis factor-alpha (TNF-α) of peritoneal fluids of rats were measured using ELISA kits. Western blot assay was performed to measure the levels of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9)  expressions after 24 h of treatment with ASDE (30, 60, and 120 μg/mL).Results: ASDE-treated rats displayed reduced numbers of total endometriotic lesions when compared with vehicle-treated controls (p < 0.01). When the rats were treated with high dose of ASDE, serum CA-125 level, as well as IL-18 and TNF-α levels in peritoneal fluids were significantly lower than that of the control group (p < 0.01); however, IL-13 level in peritoneal fluids was significantly higher than that of the control group (p < 0.01). ASDE treatment significantly suppressed the levels of MMP-2 and MMP-9 protein in 11Z cell (p < 0.01).Conclusion: The results reveal that ASDE exhibits significant anti-endometriotic effect by inhibiting inflammatory factors in rats. Thus, the plant extract can potentially be developed for the clinical management of endometriosis. Keywords: Angelica sinensis, Endometriosis, Cancer antigen, Endometriotic lesions, Matrix metalloproteinas

Wide input-voltage range boost three-level DC-DC converter with quasi-Z source for fuel cell vehicles

To solve the problem of the mismatched voltage levels between the dynamic lower voltage of the fuel cell stack and the required constant higher voltage (400V) of the DC link bus of the inverter for fuel cell vehicles, a Boost three-level DC-DC converter with a diode rectification quasi-Z source (BTL-DRqZ) is presented in this paper, based on the conventional flying-capacitor Boost three-level DC-DC converter. The operating principle of a wide range voltage-gain for this topology is discussed according to the effective switching states of the converter and the multi-loop energy communication characteristic of the DRqZ source. The relationship between the quasi-Z source net capacitor voltages, the modulation index and the output voltage, is deduced and then the static and dynamic self-balance principle of the flying-capacitor voltage is presented. Furthermore, a Boost three-level DC-DC converter with a synchronous rectification quasi-Z source (BTL-SRqZ) is additionally proposed to improve the conversion efficiency. Finally, a scale-down 1.2 kW BTL-SRqZ prototype has been created, and the maximum efficiency is improved up to 95.66% by using synchronous rectification. The experimental results validate the feasibility of the proposed topology and the correctness of its operating principles. It is suitable for the fuel cell vehicles

De novo transcriptome sequencing and comprehensive analysis of the drought-responsive genes in the desert plant Cynanchum komarovii

The figure of an agarose gel with PCR products. (TIFF 11899 kb

Enhanced oxidation resistance of active nanostructures via dynamic size effect.

A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs

3,5-Dibromo-4-oxo-2,2,6,6-tetra­methyl­piperidin-1-yl oxide

In the title compound, C9H14Br2NO2, the substituted ring exhibits a chair conformation. A crystallographic mirror plane, passing through the N atom, the O atoms and the C atom in the 4-position, bis­ects the mol­ecule

Single-switch, wide voltage-gain range, boost DC-DC converter for fuel cell vehicles

In order to match voltages between the fuel cell stacks and the DC link bus of fuel cell vehicles, a single-switch Boost DC-DC converter with diode-capacitor modules is proposed in this paper. The capacitors are charged in parallel and discharged in series. The wide voltage-gain range can be obtained by using a simple structure. In addition, the basic operating principles, the extended stages, the fault tolerant operation, and steady-state characteristics of the converter are analyzed and presented in this paper, and the small-signal model is also derived. A 400V, 1.6kW experimental prototype is developed, and the wide voltage-gain range (3.3~8) is demonstrated with a maximum efficiency at 97.25%. The experimental results validate the effectiveness and feasibility of the proposed converter and its suitability as a power interface for fuel cell vehicles