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In this paper, genetic algorithm and commutation switch based three-phase imbalanced distribution network are studied. A genetic algorithm-based commutation switch three-phase imbalance management strategy was developed, and the three-phase current distribution station area was established. A mathematical model was developed for the multi-objective optimal commutation based on the minimum imbalance degree and the minimum switching times of the low-voltage load online automatic commutation device during the commutation process. Additionally, the real-time online governance control strategies were balanced. Finally, the effectiveness of the proposed method was verified using simulation studies.

The effects of ultrasonic pretreatment on the enzymolysis thermodynamics and physicochemical properties of whey protein, and the mechanisms behind those effects, were investigated. Changes in the angiotensin-I converting enzyme (ACE) inhibitory and immunomodulatory activities of whey protein hydrolysates after ultrasonic pretreatment were also determined. Results showed that the ultrasonicated whey protein had a higher in degree of hydrolysis than the non-sonicated protein. After the pretreatment, the activation energy (Ea), enthalpy of activation (ΔH) and entropy of activation (ΔS) of whey protein enzymolysis were decreased by 15.9%, 16.8%, and 16.4%, respectively. There was no significant change in free energy (ΔG) (P > 0.05). Physicochemical analysis revealed that ultrasound had induced unfolding of the whey protein, resulting in a 43.7% increase in its surface free sulfhydryl content and a 62.6% increase in surface hydrophobicity. Ultrasound significantly decreased the protein’s α-helical content and significantly increased its β-sheets and β-turns (P

Wheat bran was solid state fermented by Fomitopsis pinicola. The results showed that the processing properties were increased by fermentation and the content of total phenol and alkylresorcinols was 5.91 and 1.55 times of the unfermented bran respectively by the 6th day. The total antioxidant capacity was 5.73 times of the unfermented sample by the 4th day. Electronic nose analysis showed that the fermented wheat bran had a special flavor. GC-MS analysis found that 4-ethyl-2-methoxy-phenol was the main flavor substance, which was sharply increased during the fermentation. Furthermore, the textural properties of the dough and bread containing fermented bran were significantly improved. The content of phytic acid in the bread was significantly decreased, while the protein, total phenol and alkylresorcinols contents were significantly increased. Results suggest that solid state fermentation by Fomitopsis pinicola is a promising way to improve wheat bran to a nutritious and flavorful cereal food ingredient.

The Chinese steppe is undergoing a drastic increase in nitrogen (N) deposition, and the precipitation in this region is predicted to increase. However, the response of soil N2O emissions to the coupling changes of precipitation and N deposition in grassland ecosystem has been seldom discussed. A manipulative field experiment was conducted to investigate the individual and interactive effects of precipitation increase and N deposition on soil N2O efflux in semi-arid temperate grassland in Inner Mongolia during the growing seasons of 2010 and 2011.The treatments included four N addition levels [20 g N m(-2) y(-1) (N20) 10 gN m(-2) y(-1) (N10), 5 g N m(-2) y(-1) (N5), and a zero-N control (CK)] and two water application levels [natural precipitation for dry (D) and 15% increase of long-term mean annual precipitation for wet (W) treatments]. Results indicated that N and water addition both significantly increased soil N2O effluxes < 0.01). The maximum N2O emissions were observed within 2-3 days after N addition to all treatments, and the N2O effluxes in W treatments were generally higher than in D treatments for the same N input level. For the treatments without N inputs, the N2O emission peak of WCK was 9.8% higher than DCK in 2010. The effect of water addition on N2O emission was more evident when more N fertilizer was applied. For the high N input treatments, the maximum N2O emission of WN20 treatment was 222.6% higher than DN20 in 2010. The changes in N and water availabilities accounted for 91.3% (2010) and 75.6% (2011) of the N2O cumulative efflux variation among different treatments (P < 0.01). The N2O effluxes were significantly affected by the interactive effect between N and water in 2010 and 2011 (P < 0.05). Significant interannual variability in the cumulative N2O emissions was observed, the cumulative N2O emissions in 2011 were significantly lower than those in 2010 even though the summer of 2011 experienced higher rainfall (P < 0.01). Temperature also significantly influenced soil N2O emission apart from the effects of water and N. The temperature change accounted for 41.3% (W) to 47.2% (D) of the temporal variations in N2O emission during the relatively dry 2010. The combined changes in soil moisture, NH4+-N, and temperature accounted for 43.1% (D) to 54.5% (W) of the temporal variations in N2O emission in the relatively wet year of 2011. (C) 2015 Elsevier B.V. All rights reserved.

Global change will lead to increases in regional precipitation and nitrogen (N) deposition in the semi-arid grasslands of northern China. We investigated the responses of vegetation carbon (C) pools to simulated precipitation and N deposition increases through field experiments in a typical steppe in Inner Mongolia. The treatments included NH4NO3 addition at concentrations of 0 (CK), 5 (LN, low nitrogen), 10 (middle nitrogen, MN), and 20 (HN, high nitrogen) (g m−2 a−1) with and without water. After three consecutive years of treatment, from 2010 to 2012, water addition did not significantly change the size of the total vegetation C pools, but it significantly decreased the ratio of root:shoot (R:S) (P = 0.05) relative to controls. By contrast, N addition significantly increased the total vegetation C pools. The C pools in the LN, MN and HN treatments increased by 22, 39 and 44 %, respectively. MN produced the largest effect among the N concentrations, although differences between N-added treatments were not significant (P > 0.05). N addition significantly reduced the ratio of root:shoot (R:S) (P = 0.03). However, there were no significant interactive effects of water and N addition on the vegetation C pools.

Water and nitrogen are primary limiting factors in semiarid grassland ecosystems. Our knowledge is still poor regarding the interactive effects of water and N addition on soil microbial communities, although this information is crucial to reveal the mechanisms of the terrestrial ecosystem response to global changes. We addressed this problem by conducting a field experiment with a 15% surplus of the average rainfall under three levels of N addition (50, 100, and 200 kg N ha(-1) yr(-1)) in two consecutive years in Inner Mongolia, China. Microbial community composition and functional diversity were analyzed based on phospholipid fatty acids (PLFA) and BIOLOG techniques, respectively. The results showed that water addition did not affect the soil microbial community composition, but much more yearly precipitation generally decreased the PLFA concentration, which implied a fast response of soil microbes to changes of water condition. Soil fungi was depressed only by N addition at the high level (200 kg N ha(-1) yr(-1)) and without hydrologic leaching, while Gram-negative bacteria was suppressed probably by plant competition at high level N addition but with hydrologic leaching. The study found unilateral positive/negative interactions between water and N addition in affecting soil microbial community, however, climate condition (precipitation) could be a significant factor in disturbing the interactions. This study highlighted that: (1) The sustained effect of pulsed water addition was minimal on the soil microbial community composition but significant on the microbial community functional diversity and (2) the complex interaction between water and N addition on soil microbial community related to the inter-annual variation of the climate and plant response.

Litter decomposition is the fundamental process in nutrient cycling and soil carbon (C) sequestration in terrestrial ecosystems. The global-wide increase in nitrogen (N) inputs is expected to alter litter decomposition and, ultimately, affect ecosystem C storage and nutrient status. Temperate grassland ecosystems in China are usually N-deficient and particularly sensitive to the changes in exogenous N additions. In this paper, we conducted a 1,200-day in situ experiment in a typical semi-arid temperate steppe in Inner Mongolia to investigate the litter decomposition as well as the dynamics of litter C and N concentrations under three N addition levels (low N with 50 kg N/(hm2·a) (LN), medium N with 100 kg N/(hm2·a) (MN), and high N with 200 kg N/(hm2·a) (HN)) and three N addition forms (ammonium-N-based with 100 kg N/(hm2·a) as ammonium sulfate (AS), nitrate-N-based with 100 kg N/(hm2·a) as sodium nitrate (SN), and mixed-N-based with 100 kg N/(hm2·a) as calcium ammonium nitrate (CAN)) compared to control with no N addition (CK). The results indicated that the litter mass remaining in all N treatments exhibited a similar decomposition pattern: fast decomposition within the initial 120 days, followed by a relatively slow decomposition in the remaining observation period (120–1,200 days). The decomposition pattern in each treatment was fitted well in two split-phase models, namely, a single exponential decay model in phase I ( 398 days). The three N addition levels exerted insignificant effects on litter decomposition in the early stages ( 0.05). However, MN and HN treatments inhibited litter mass loss after 398 and 746 days, respectively (P 0.05). The effects of these two N addition forms differed greatly from those of CAN after 746 and 1,053 days, respectively (P 0.05). Our results indicated that exogenous N additions could exhibit neutral or inhibitory effects on litter decomposition, and the inhibitory effects of N additions on litter decomposition in the final decay stages are not caused by the changes in the chemical qualities of the litter, such as endogenous N and C concentrations. These results will provide an important data basis for the simulation and prediction of C cycle processes in future N-deposition scenarios.

Short-term nitrous oxide (N2O) pulse emissions caused by precipitation account for a considerable portion of the annual N2O emissions and are greatly influenced by soil nitrogen (N) dynamics. However, in Chinese semiarid temperate steppes, the response of N2O emissions to the coupling changes of precipitation and soil N availability is not yet fully understood. In this study, we conducted two 7-day field experiments in a semiarid temperate typical steppe of Inner Mongolia, China, to investigate the N2O emission pulses resulting from artificial precipitation events (approximately equivalent to 10.0 mm rainfall) under four N addition levels (0, 5, 10, and 20 g N/(m(2)center dot a)) using the static opaque chamber technique. The results show that the simulated rainfall during the dry period in 2010 caused greater short-term emission bursts than that during the relatively rainy observation period in 2011 (P 0.05) with single water addition. The peak values of N2O efflux increased with the increasing N input. Only the treatments with water and medium (WN10) or high N addition (WN(2)0) significantly increased the cumulative N2O emissions (P

Cultivation is one of the most important human activities affecting the grassland ecosystem besides grazing, but its impacts on soil total organic carbon (C), especially on the liable organic C fractions have not been fully understood yet. In this paper, the role of cropping in soil organic C pool of different fractions was investigated in a meadow steppe region in Inner Mongolia of China, and the relationships between different C fractions were also discussed. The results indicated that the concentrations of different C fractions at steppe and cultivated land all decreased progressively with soil depth. After the conversion from steppe to spring wheat field for 36 years, total organic carbon (TOC) concentration at the 0 to 100 cm soil depth has decreased by 12.3% to 28.2%, and TOC of the surface soil horizon, especially those of 0–30 cm decreased more significantly (p

The effects of ultrasonic treatment during proteolysis on kinetic characterisation of the hydrolysis of defatted wheat germ protein (DWGP), and on ACE-inhibitory activity of the hydrolysate, were investigated. The effects of ultrasonic pretreatment on the release of peptides with ACE-inhibitory were also studied. The results showed that the value of k A for DWGP hydrolysis under ultrasonic irradiation increased by about 22.2%, and K M decreased about 13.0%, compared with that obtained without ultrasound. Analysis of ACE-inhibitory activity indicated that ultrasound during enzyme treatments had less effect on the ACE-inhibitory activity, while ultrasonic pretreatment caused a 21.0–40.7% increase in ACE-inhibitory activity of DWGP hydrolysate. Analyses of hydrophobicity, microstructure, and amino acid composition revealed that ultrasonic pretreatment could accelerate the release of hydrophobic amino acids from DWGP during enzymatic hydrolysis. In conclusion, ultrasonic treatment during proteolysis could facilitate the enzymatic hydrolysis of DWGP, whereas ultrasonic pretreatment could promote the release of ACE-inhibitory peptides from DWGP during enzymatic hydrolysis.

We examined the effects of simulated rainfall and increasing N supply of different levels on CO2 pulse emission from typical Inner Mongolian steppe soil using the static opaque chamber technique, respectively in a dry June and a rainy August. The treatments included NH4NO3 additions at rates of 0, 5, 10, and 20 g N/(m(2)·year) with or without water. Immediately after the experimental simulated rainfall events, the CO2 effluxes in the watering plots without N addition (WCK) increased greatly and reached the maximum value at 2 hr. However, the efflux level reverted to the background level within 48 hr. The cumulative CO2 effluxes in the soil rang ed from 5.60 to 6.49 g C/m(2) over 48 hr after a single water application, thus showing an increase of approximately 148.64% and 48.36% in the effluxes during both observation periods. By contrast, the addition of different N levels without water addition did not result in a significant change in soil respiration in the short term. Two-way ANOVA showed that the effects of the interaction between water and N addition were insignificant in short-term soil CO2 effluxes in the soil. The cumulative soil CO2 fluxes of different treatments over 48 hr accounted for approximately 5.34% to 6.91% and 2.36% to 2.93% of annual C emission in both experimental periods. These results stress the need for improving the sampling frequency after rainfall in future studies to ensure more accurate evaluation of the grassland C emission contribution.

This research was to explore the mechanism of ultrasonic impact on protease activity. The effects of energy-gathered ultrasound on the activity, kinetics, thermodynamics and molecular structure of Alcalase were investigated with the aid of the chemical reaction kinetics model, Arrhenius equation, Eyring transition state theory, fluorescence spectroscopy and circular dichroism (CD) spectroscopy. Results showed that ultrasound had effect on the activity of Alcalase. The highest Alcalase activity was achieved when the sample was treated with energy-gathered ultrasound at 80 W for 4 min, under which the enzyme activity was increased by 5.8% over the control. After the treatment, thermodynamics parameters Ea, ΔH, ΔS and ΔG were reduced by 70.0%, 75.8%, 34.0% and 1.3%, respectively. Besides, fluorescence and CD spectra revealed that the ultrasonic treatment had increased the number of tryptophan on Alcalase surface slightly, increased number of α-helix by 5.2%, and reduced the number of random coil by 13.6%.

There is a great demand for developing efficient enzymolysis methods in order to increase the enzymolysis efficiencies and activities of angiotensin converting enzyme (ACE) inhibitory peptides from wheat germ protein. The enzymolysis kinetics, ACE inhibitory activity of peptide and conversion rate of protein were studied using sweep frequency and pulsed (SFP) ultrasound-assisted enzymolysis and the results were compared with traditional enzymolysis. The studied factors were enzymolysis time and substrate concentration. By considering the activity of ACE inhibitory peptide and operation cost, the recommended conditions of SFP ultrasound-assisted enzymolysis were enzymolysis time of 120 min and substrate concentration of 24.0 g/L, which gave high conversion rates of protein (60.7%) and ACE inhibitory activity of peptide (65.9%). Compared to traditional enzymolysis, SFP ultrasound-assisted enzymolysis significantly increased the initial reaction rate (V) by 60.0% at substrate concentration of 24.0 g/L, increased the apparent breakdown rate constant (kA) by 66.7%, decreased the apparent constant (KM) by 6.9%, and raised the conversion rate of protein by 35.5% and ACE inhibitory activity of peptides by 35.6% under the recommended conditions. It has been concluded that SFP ultrasound can remarkably raise the enzymolysis efficiency and activity of ACE inhibitory peptides from wheat germ protein.