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In this paper, a set of wireless communication module based on LoRa technology is developed, and a complete local area network wireless communication solutions satisfying long distance and low power consumption is proposed, which has wide wireless coverage, strong penetration and star architecture. By using LoRa communication, the data of the distribution terminal can be transmitted to the data collection unit seamlessly. The data is more safe and reliable. Through practical field application, the communication system is verified.

This paper studies a seamless power supply strategy for a ship-controlled inverter system, which is installed on the ship and includes rectifiers, inverters, the storage battery. Based on the V/f control and the P/Q control, an improved software phase-locked method is proposed by combining the working characteristics when the operating mode is switching to guaranteed the continuity and stability of grid voltage phase under all kinds of switching conditions, which can lay a solid foundation for seamless switching of different operation modes and optimize controls’ parameters. Finally, a platform of simulation experiment for switching operation modes between ship generator and rectifier (power storage)-inverter is established. The results of simulation and experiment prove the efficiency and superiority of the seamless power supply strategies for the ship-controlled inverter system.

In this paper, a feature extraction method for transient information in distribution network is presented. The method is based on wavelet gray moment and is simulated by Matlab. This method can effectively extract the typical fault of various distribution networks and the operating conditions of complex working conditions, such as short circuit, broken line, grounding, closing inrush and lightning strike. Finally, the proposed method is verified by actual sampling data, which proves that the method has practical effect and application prospect.

Changes in growth and distribution of inorganic mineral elements and organic active substances in seedlings of A. vera were examined under treatments of −0.44 and −0.88 MPa polyethylene glycol 6000 (PEG) and corresponding isosmotic sodium chloride (NaCl). All stress treatments inhibited plant growth, with NaCl severely inhibiting the growth of the seedlings than PEG. However, leaf biomass did not change significantly. The nitrogen concentration under PEG was maintained higher than that under NaCl. Salinity caused more severe ionic imbalance than dehydration. However, when the concentration of NaCl was increased, ion homeostasis was maintained. Stressors induced an increase in aloin concentration in leaves, especially in young leaves. Polysaccharide concentrations in leaves did not change under dehydration. However, the polysaccharide concentration decreased in the middle and base leaves under NaCl. A. vera exhibited high adaptability to suitable osmotic stress, which increases its main active ingr...

This paper presents a nine-level cascade inverter and gives its mathematical model of SHEPWM with Walsh functions. Based on the model, the solutions of the switching angles in the full range of fundamental voltage are calculated and listed, which is beneficial to the application of the nine-level cascade inverter.

The wavelet PWM (WPWM) technique has been applied in the two-level inverters successfully, but it is impossible to apply directly the WPWM technique to multilevel inverters. This paper proposes two kinds of WPWM techniques suitable for a cascaded multilevel inverter, analyzes the control strategy with the WPWM and obtains the design of its parameters. The simulation results show the proposed WPWM methods can get high magnitudes of the output fundamental frequency component, low total harmonic distortion and simpler digital implementation.

Use water quality stability theory, through the experiment find coking wastewater as cooling water added water treatment and control technology. The static and dynamic combination of methods, will coking wastewater biochemical treatment to countries after “the comprehensive sewage discharge standards “(GB8978-1996 level 1) as an experimental water, water by the MBR membrane bioreactor, deep treatment after deep treatment of water corrosion and scale water quality stable, and the effluent treatment can satisfy enterprise circulating cooling water added water quality requirements.

This paper introduces a digital multi-mode boost converter with wide range of input voltage for an energy recycling load system. The boost converter is controlled digitally with constant off- time/constant frequency hybrid pulse width modulation (PWM) control. Constant off-time control is to avoid the limit cycle oscillation and gain a high gain when the input voltage is far less than the output voltage. Otherwise, constant frequency PWM is adopted. Finally, A 3.6kW DC/DC boost converter with twelve 300W channels in parallel was built for an energy recycling load system and the experimental results testify it to get high gain up to 49 and high efficiency up to about 98%.

This paper presents the principle and implementation of the wavelet PWM (WPWM) technique based on non-dyadic type multi-resolution analyses (MRAs) for three-phase inverters, analyses and gives the impacts of the initial values of scales by WPWM on the three-phase full-bridge and half- bridge inverter's output features, which is beneficial to choose suitable initial values of scales. Finally, the performances of WPWM technique are compared with those obtained using SPWM and SVPWM technique under same conditions. Simulation results show that the WPWM technique can get smaller THD and more disperser spectrum than SPWM and SVPWM technique, which provide theoretical basis for the application of the WPWM efficiently in practice.

A facile strategy for the preparation of two isomeric drospirenones 13 and 16 possessing a 14β-hydrogen was developed, using 3β-hydroxyandrost-5-en-17-one as the starting material. The total synthetic route involves eight steps, giving 2% overall yield. The structures of the main compounds 11, 13, 14 and 16 were determined by single crystal XRD analysis.

Responses ofUlva proliferaandUlva linzato Cd2+stress were studied. We found that the relative growth rate (RGR), Fv/Fm, and actual photochemical efficiency of PSII (Yield) of twoUlvaspecies were decreased under Cd2+treatments, and these reductions were greater inU. proliferathan inU. linza.U. proliferaaccumulated more cadmium thanU. linzaunder Cd2+stress. WhileU. linzashowed positive osmotic adjustment ability (OAA) at a wider Cd2+range thanU. prolifera.U. linzahad greater contents of N, P, Na+, K+, and amino acids thanU. prolifera. A range of parameters (concentrations of cadmium, Ca2+, N, P, K+, Cl−, free amino acids (FAAs), proline, organic acids and soluble protein, Fv/Fm, Yield, OAA, and K+/Na+) could be used to evaluate cadmium resistance inUlvaby correlation analysis. In accordance with the order of the absolute values of correlation coefficient, contents of Cd2+and K+, Yield, proline content, Fv/Fm, FAA content, and OAA value ofUlvawere more highly related to their adaptation to Cd2+than the other eight indices. Thus,U. linzahas a better adaptation to Cd2+thanU. prolifera, which was due mainly to higher nutrient content and stronger OAA and photosynthesis inU. linza.

To investigate the physiological responses and adaptation mechanisms of Enteromorpha to seawater salinity stress, a laboratory experiment with Enteromorpha linza and E. prolifera was conducted to study their fresh mass (FM), relative growth rate (RGR), relative electrical conductivity (REC), chlorophyll (Chl) and carotenoid (Car) contents, Chl a/Chl b, Chl/Car, chlorophyll fluorescence parameters, and osmotic adjustment ability (OAA) under the stress of different salinity levels of diluted and concentrated seawater for 10 days. Compared with the control, 10%-200% salinity seawater increased the FM and RGR of the two Enteromorpha species obviously, 100% and 50% salinity seawater made the FM and RGR of E. linza and E. prolifera peaked, respectively, while 300% salinity seawater decreased the FM and RGR of E. linza and E. prolifera significantly, with the decrement being larger for E. linza. The biomass of E. linza and E. prolifer only had an increase in 50% and 100% sanity seawater and in 10%, 50%, 100%, and 200% salinity seawater, respectively. The Chl and Car contents and Chl a/Chl b of E. linza and E. prolifera had a significant increase in 10% salinity seawater, but decreased after an initial increase with the increasing salinity level of seawater. The Chl and Car contents and Chl a/Chl b of E. linza and E. prolifera peaked in 100% and 50% salinity seawater, respectively. With increasing salinity of seawater, the light use efficiency (alpha), maximal photochemical efficiency of PS II (F(v)/F(m)), actual photochemical efficiency of PS II in the light (Yield), maximal relative electron transport rate (rETR(max)), and half-saturation light intensity (I(k)) of E. linza and E. prolifera all showed the same variation trend as Chl. 10% -300% salinity seawater enabled E. linza and E. prolifera to express certain osmotic adjustment ability (OAA), and the OAA of E. linza and E. prolifer peaked in 100% and 50% salinity seawater, respectively. The growth of Enteromorpha had no correlation with Chl/Car, but was significantly negatively correlated with REC and positively correlated with Chl, Car, Chl a/ Chl b, F(v)/F(m), Yield, rETR(max), alpha, I(k), and OAA. To sum up, 100% salinity was the optimal salt concentration for the growth of E. linza, and 50% salinity was optimal for E. prolifera. E. prolifera could adapt to a wider range of salinity than E. linza. The parameters REC, Chl, Car, Chl a/Chl b, F(v)/F(m), Yield, rETR(max), alpha, I(k), and OAA could be used to evaluate the salt adaptation of Enteromorpha.

A sand culture pot experiment was conducted to study the eco-physiological responses of high-latitude transplanted mangrove Aegiceras corniculatum seedlings to varying concentration of NaCl (0, 100, 200, 300, and 400 mmol x L(-1)). Under the stress of 100 mmol NaCl x L(-1), the seedling growth was slightly promoted; whereas at 300 mmol NaCl x L(-1), the plant height, stem basal diameter, fresh and dry mass, and root/shoot ratio were decreased significantly. High salt stress inhibited the leaf superoxide dismutase (SOD) and peroxidase (POD) activities, increased the leaf malondialdehyde (MDA) content, and decreased the leaf chlorophyll and carotenoids contents as well as the total soluble sugar and free amino acid contents in different organs. Under the stress of different concentration NaCl, the Na+ contents in leaf, stem, and root increased rapidly while the K+ contents had a relatively decrease, resulting in a rapid decrease of K+/Na+ ratio and an imbalance between K+ and Na+ in A. corniculatum vegetative organs. When the NaCl concentration in the medium was higher than 300 mmol x L(-1), the C and N metabolism of A. corniculatum vegetative organs was maladjusted, which inhibited the normal growth of the seedlings, resulting in a significant decrease in the plant height and fresh and dry mass.

Taking Ximen island of Yueqing bay, the biggest tidal range area among the coasts of China, as study site, an investigation was made on the survival rate, growth characteristics, and attached barnacles of 1- and 3-year-old Kandelia candel seedlings at the elevations 1.96, 1.66, 1.35, and 1.03 m above the zero tidal level of Yellow Sea. Significant differences were observed in the survival rate and growth situation of the seedlings among the elevations. There were two barnacle species, Balanus albicostatus and Balanus amphitrite amphitrite, and B. albicostatus was the major species which attached K. candel most seriously at elevation 1.35 m. The critical tidal level for K. candel in the site was 1.66 m above the zero tidal level, i.e., at least 1.29 m higher than the local mean sea level, and the flooding time per tide cycle being less than 3.65 h. Barnacle, strong tide, and extreme weather event were the main reasons for the higher critical tidal level.

A pot experiment was conducted to study the effects of salt (ST), waterlogging (WL), and their combination (SW) at post-anthesis on the grain yield and its starch and protein components of wheat cultivars Yangmai 12 and Huaimai 17. Comparing with the control, treatments ST, WL, and SW, especially ST and SW, decreased the allocation of nitrogen and carbon assimilates at pre- and post-anthesis to the grains significantly, resulting in an obvious decrease of grain yield and its protein and starch contents. Both ST and SW had significant negative effects on the glutenin/gliadin and amylase/amylopectin ratios in the grains, compared to CK and WL. Yangmai 12 was more sensitive to ST than SW, while Huaimai 17 was in adverse. WL decreased the accumulation of protein and starch in the grains of the two cultivars. Except that the glutenin and albumin in Huaimai 17 had some increase, the globulin and gliadin in Huaimai 17 and all protein components in Yangmai 12 were decreased under WL.

The steric structure of the title compound, C19H26O2, has been reported previously [Sondheimer et al. (1960). J. Am. Chem. Soc. 82, 3209–3214] as 14-isoandrosten by optical rotatory dispersion data. The X-ray data of the single crystal shows that ring A has a chair conformation and ring C has a boat conformation. An O—H⋯O hydrogen bond between the hydroxyl group and the carbonyl O atom of an adjacent molecule helps to establish infinite chains along the body diagonal of the unit cell.