An integrated Z-source inverter for the single-phase single-stage grid-connected photovoltaic system is proposed in this paper. The inverter integrates three functional blocks including maximum-power-point-tracking, step-up/down DC-side voltage and output grid-connected current. According to the non-minimum-phase characteristic presented in DC-side and the functional demands of the system, two constant-frequency sliding-mode controllers with integral compensation are proposed to guarantee the system robustness. By using two controllers, the effects caused by the non-minimum-phase characteristic are mitigated. Under the circumstance of that the input voltage or the grid-connected current changes suddenly, the notches/protrusions following the over-shoot/ under-shoot of the DC-bus voltage are eliminated. The quality of grid-connected current is ensured. Also, a small-signal modelling method is employed to analyze the close-loop system. A 300W prototype is built in the laboratory. A solar-array simulator (SAS) is used to verify the systematic responses in the experiment. The correctness and validity of the inverter and proposed control algorithm are proved by simulation and experimental results.

Accurate prediction of blasting vibration should be achieved in mine blasting production practice. It is also a critical problem in the field of blasting vibration control technology research. In this research paper, on the basis of the previous research results and taking account into the reflection principle of elastic wave at the free interface, the authours proposes the blasting seismic wave propagation model. In addition, the blasting positive elevation effect are theoretically explained in detail, and the vibration velocity prediction formula of the positive elevation effect is derived. Finally, the positive elevation effect mechanism and the step (positive) formula are calibrated based on the on-site monitoring data of blasting vibration of Qipanjing Jinou coal mine. In beirf, a theoretical basis is laid by this paper for similar blasting projects.

Considering concrete nonlinearity, the wave height limit between small and large amplitude sloshing is defined based on the Bernoulli equation. Based on Navier-Stokes equations, the mathematical model of large amplitude sloshing is established for a Concrete Rectangle Liquid-Storage Structure (CRLSS). The results show that the seismic response of a CRLSS increases with the increase of seismic intensity. Under different seismic fortification intensities, the change in trend of wave height, wallboard displacement, and stress are the same, but the amplitudes are not. The areas of stress concentration appear mainly at the connections between the wallboards, and the connections between the wallboard and the bottom.

Staphylococcus aureus (S. aureus) has been recognized as one of the important zoonotic pathogens. However, it was limited about the epidemiology and genetic characteristics of S. aureus isolated from pigs in Hunan province, china. The aim of this study was to determine the characteristics of 163 S. aureus isolated from 590 pigs in Hunan Province, China. All isolates were characterized by agr typing, detection of virulence genes and antibiotic resistance genes, lethal test of mice and antibiotic susceptibility tests. The results showed that 30 strains of the 163 isolates were divided into agrI (18.40%), agrII (36/163, 22.09%), agrIII (20/163, 12.27%,), agrIV (20/163,12.27%) and the remaining 57 isolates were amplified negative by agr primers. In the 163 isolates, the detection rate of the virulence genes hlb, hld, hla, icaA, seb, fnbA, eta, etb, sea, tst and pvl ranged from 2.45% to 100%. The 43 isolates that were lethal to the mice, had β-hemolytic activity, the number of virulence genes of which was 7.8% higher than that of the remaining 120 non-fatal strains. The resistance rates of the 163 isolates to the 15 antibiotics were 0% (0/163) - 100% (163/163). All isolates were susceptible to Vancomycin and only 7 isolates were methicillin - resistant S. aureus (MRSA). The detection rates of the 11 resistance genes was 0% (0/163) - 100% (163/163). This study first to describes the epidemiology and characteristics of S. aureus from pigs in Hunan Province, which will help in tracking the evolution of epidemic strains and preventing pig-human transmission events.

Objective: This study aimed to investigate developmental changes of the thymus and intra- thymic IL-1β, IL-6 and TNF-α expression in weaned Sprague-Dawley rats induced by lipopolysac- charide.

Methods: Forty healthy weaned rats aged 26 days and weighing 83±4 g were randomly and equally divided into two groups. The lipopolysaccharide group was treated daily with a single injection of lipopolysaccharide for 10 consecutive days, and the saline group was treated with an equal volume of sterilized saline. On the 1st, 4th, 7th and 10th day, histological changes and distribu- tion of IL-1β-, IL-6- and TNF-α-positive cells were detected in the thymus by hematoxylin-eosin and immunohistochemistry staining, respectively. Subsequently, the expression levels of IL-1β, IL-6 and TNF-α were evaluated in the thymus by the ELISA method.

Results: Thymus weight and index were significantly smaller in lipopolysaccharide-treated rats than in saline-treated rats (p<0.05), but no substantial changes were found in the thymus microstructure after lipopolysaccharide induction. Moreover, a large number of IL-1β-, IL-6- and TNF-α-positive cells were observed with brownish-yellow color and mainly distributed in the thy- mus parenchyma, both integrated optical density and average optical density increased signifi- cantly in lipopolysaccharide-treated rats than those in saline-treated rats. Compared with the saline group, most of the thymic homogenates had higher levels of IL-1β, IL-6 and TNF-α in the lipopolysaccharide group on different days.

Conclusion: These findings indicate that the thymus atrophied after lipopolysaccharide induction in weaned Sprague-Dawley rats, and excessive production of intrathymic IL-1β, IL-6 and TNF-α was probably involved in the atrophic process.

In this study, cubic and cylindrical cement mortar specimens were first subjected to high temperatures, then the cubic and cylindrical specimens were taken out and conducted with uniaxial compressive test and splitting tensile test, respectively. The effect of the length to side ratio on the uniaxial compressive properties and the effect of thickness-to-diameter ratio on the splitting tensile properties of cement mortar specimens after high temperature were studied. Test results show that: (1) With temperature increasing from 25°C (room temperature) to 400°C, the compressive strength and elastic modulus of cubic specimens with three kinds of side lengths decrease; the decreasing rates of compressive strength and elastic modulus of cubic specimen with side length of 70.7 mm is higher than those of cubic specimens with side length of 100 mm and 150 mm, and the strain at the peak stress of cubic specimens with three kinds of side lengths increase. (2) After the same temperature, the tensile strength of cylindrical specimen decreases with the thickness-to-diameter ratio increasing from 0.5 to 1.0. The decreasing rate of tensile strength of cylindrical specimen with thickness-to-diameter ratio is highest when the temperature is 25°C (room temperature), followed by that after the temperature of 200°C, and that after the temperature of 400°C is the lowest.

The welfare and healthy growth of poultry under intensive feeding conditions are closely related to their living environment. In spring, the air quality considerably decreases due to reduced ventilation and aeration in cage systems, which influences the meat quality and health of broilers during normal growth stages. In this study, we analyzed the airborne bacterial communities in PM2.5 and PM10 in cage broiler houses at different broiler growth stages under intensive rearing conditions based on the high-throughput 16S rDNA sequencing technique. Our results revealed that PM2.5, PM10 and airborne microbes gradually increased during the broiler growth cycle in poultry houses. Some potential or opportunistic pathogens, including Acinetobacter, Pseudomonas, Enterococcus, Microbacterium, etc., were found in the broiler houses at different growth stages. Our study evaluated variations in the microbial communities in PM2.5 and PM10 and potential opportunistic pathogens during the growth cycle of broilers in poultry houses in the spring. Our findings may provide a basis for developing technologies for air quality control in caged poultry houses.

Koumiss has beneficial therapeutic effects on bacterial diseases. Four antibacterial com- pounds from yeasts ( Kluyveromyces marxianus and Saccharomyces cerevisiae) in koumiss were evaluated for their antibacterial effects against three Gram-negative bacteria, three Gram-positive bacteria and five pathogenic Escherichia coli strains. The antibacterial compounds from yeasts in koumiss were extracted, and their main components were determined. The inhibition zones were analyzed, and their minimum inhibition concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined. Aqueous phases of Kluyveromyces marxianus and Saccharomyces cerevisiae at pH 2.0 and 8.0 produced larger inhibition zones than those in other phases, and then antibacterial compounds from K. marxianus (K2, pH=2.0; K8, pH=8.0) and S. cerevisiae (S2, pH=2.0; S8, pH=8.0) were obtained. Their main components were organic acids and killer toxins. K2 had more propanoic acid and S2 had more oxalic acid than others. The inhibition zones of K2, K8, S2 and S8 against three Gram-negative bacteria and three Gram-positive bacteria were 12.03-23.30 mm, their MICs were 0.01-0.13 g/mL, and MBCs were 0.03-0.50 g/mL. Meantime, the inhibition zones of K2, K8, S2 and S8 against five pathogenic E. coli were 16.10-25.26 mm, their MICs were 0.03-0.13 g/mL, and MBCs were 0.13-1.00 g/mL. These four antibacterial compounds from yeasts in koumiss had broad antibacterial spectrum. In addition, K2 and S2 were better than K8 and S8.