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Landscape water is an important part of urban water systems, and excessive nitrogen affects its ecological functions. This study aimed to investigate the temporal and spatial distribution characteristics and driving factors of the community structure of denitrifying bacteria from landscape water. The functional gene

In order to study the spatial and temporal distribution characteristics of aerobic denitrification bacteria in the sediments of Gangnan Reservoir, the aerobic denitrification bacterial community was analyzed using a MiSeq high-throughput sequencing technique based on the

Dissolved organic matter(DOM) is an important component of the organic matter in the environment. This study explored the characteristics of DOM. The components and spectral characteristics of rainwater DOM were measured using Ultraviolet-visible absorption spectrum(UV-vis) and three-dimensional fluorescence spectrum in the Hebei province. The results showed significant differences for DOM molecular weight in the northern, central, and southern region; the DOM of the northern region exhibited the lowest molecular weight. Two humic-like(C1 and C4), one protein-like(C2) and one fulvic-like(C3) components were identified by parallel factor(PARAFAC) analysis. Component C2 had a significant positive correlation with components C3 and C4(

Dissolved organic matter (DOM) plays an important role in the evolution of microbial communities. Meanwhile, ecological water delivery is an important feature of Baiyangdian Lake. To explore how the structure of the aerobic denitrification bacteria community responds to DOM during the water delivery period, the DOM components of water were examined and high-throughput sequencing of aerobic denitrification bacteria was performed. The results showed significant differences in DOM concentration in Baiyangdian Lake, with the estuary area exhibiting lower DOM concentrations. The water exhibited strong autogenous source, while DOM in the estuary area had a higher molecular weight and degree of humification. Three protein-like substances (C1, C2, and C4) and one humic-like substance (C3) were identified through PARAFAC. The protein-like substances accounted for the major proportion of DOM, which was consistent with the results of fluorescence regional integration (FRI). The genera of the water body were mainly in the Protebacterice phylum, including

In order to reveal the interaction of overlying water-interstitial water nitrogen and phosphorus nutrient salt in summer at the entrance region of Baiyangdian Lake, this study sampled six main rivers in the region during July 2019. An analysis of the overlying water and interstitial water quality characteristics and the diffusion flux of applied nutrients at the sediment-water interface revealed the effects of nutrient diffusion on sediments and overlying water. The overlying water analysis showed that the water quality was slightly alkaline in the Baiyangdian Lake. The content of dissolved oxygen (DO) was lower, which provided an anaerobic environment for the release of endogenous pollutants from sediments. The ammonia nitrogen (NH

The chromophoric dissolved organic matter (CDOM), the main component of dissolved organic matter, affects the morphological characteristics, migration, and conversion of pollutants in water. Based on UV-vis spectra and excitation emission matrix spectroscopy (EEMs) combined with the parallel factor analysis (PARAFAC), the spatial distribution and spectral characteristics were investigated and source analysis of CDOM was performed. Thus, the spatiotemporal differences in the CDOM in Gangnan Reservoir were analyzed. Results showed that

To isolate the aerobic denitrification bacteria suitable for water quality in the low-temperature period of Baiyangdian Lake, a water quality investigation and bioinformatics analysis of the aerobic denitrification bacterial community were carried out using a MiSeq high-throughput sequencing technique based on

Combined with on-site water quality investigation and

UV-visible absorption spectroscopy, fluorescence spectroscopy, and parallel factor analysis were used to analyze the composition of chromophoric dissolved organic matter (CDOM) in the waters of the Wangchuan River in summer, and the source of this CDOM was explored. The redundant analysis method and Pearson correlation were used to analyze the correlation between optical parameters and water quality parameters. The results showed that the CDOM of the Wangchuan River is composed of the tryptophan-like component C1 (245, 300/335 nm), the short-wave humus component C2 (240, 320-340/405 nm), and the long-wave humus component C3 (270, 350-370/470 nm), in which components C1 and C2 have some homology (

The relationship between CDOM (Chromophoric dissolved organic matter) and the bacterial community was investigated in ice-covered Baiyangdian Lake. The results showed that environmental parameters significantly differed in Baiyangdian Lake, whereas a-diversity was not significantly different. Moreover, the microbial and functional communities exhibited significant differences, and T (Temperature), pH, ORP (Oxidation-reduction potential), DO (Dissolved oxygen), NO3&minus, N, NH4+-N, and Mn (Manganese) were the main environmental factors of these differences, based on redundancy analysis and the Mantel test. Biomarkers of the microbial and functional communities were investigated through linear discriminant analysis effect size and STAMP analysis. The number of biomarkers in the natural area was highest among the typical zones, and most top functions were related to carbohydrate metabolism. Two protein-like components (C1 and C2) and one humic-like component (C3) were identified by parallel factor analysis, and C1 was positively related to C2 (R = 0.99, p &lt, 0.001), indicating the same sources. Moreover, CDOM significantly differed among the typical zones (p &lt, 0.001). The high biological index, fluorescence index, &beta, &alpha, and low humification index indicated a strong autochthonous component and aquatic bacterial origin, which was consistent with the results of UV-vis absorption spectroscopy. Network analysis revealed non-random co-occurrence patterns. The bacterial and functional communities interacted closely with CDOM. The dominant genera were CL500-29_marine_group, Flavobacterium, Limnohabitans, and Candidatus_Aquirestis. Random forest analysis showed that C1, C2, and C3 are important predictors of &alpha, and &beta, diversity in the water bacterial community and its functional composition. This study provides insight into the interaction between bacterial communities and DOM (Dissolved organic matter) in ice-covered Baiyangdian Lake.

The mechanism and factors influencing nitrogen loss in the Zhoucun reservoir were explored during the spring. The results showed that the nitrate and total nitrogen concentration decreased from 1.84 ± 0.01 mg/L and 2.34 ± 0.06 mg/L to 0.06 ± 0.01 mg/L and 0.48 ± 0.09 mg/L, respectively. Meanwhile, the nitrate and total nitrogen removal rate reached 97.02% ± 0.25 and 79.38% ± 3.32, respectively. Moreover, the abundance of nirS gene and aerobic denitrification bacteria increased from 1.04–3.38 × 103 copies/mL and 0.71 ± 0.22 × 102 cfu/mL to 5.36–5.81 × 103 copies/mL and 8.64 ± 2.08 × 103 cfu/mL, respectively. The low MW fractions of DOM (

Here, the ion-exchangeable form of nitrogen (IEF-N), weak-acid extractable form of nitrogen (WAEF-N), strong-alkali extractable form of nitrogen (SAEF-N), strong-oxidant extractable form of nitrogen (SOEF-N), residue nitrogen (Res-N), and total nitrogen (TN) showed spatial differences, and most of the sediment nitrogen fractions exhibited positive correlations in Baiyangdian Lake. High-throughput sequencing analysis revealed that the aerobic denitrification microbial community was composed of proteobacteria (42.04%&ndash, 99.08%) and unclassified_bacteria (0.92%&ndash, 57.92%). Moreover, the microbial community exhibited significant differences (R2 = 0.4422, P &lt, 0.05) on the basis of the adonis analysis. T(temperature), Moisture content (MC), sediment total phosphorus (STP), ion-exchangeable form of ammonia (IEF-NH4+-N), weak-acid extractable form of ammonia (WAEF-NH4+-N), weak-acid extractable form of nitrate (WAEF-NO3--N), and strong-alkali extractable form of ammonia (SAEF-NH4+-N) were the dominant environmental factors and explained 11.1%, 8.2%, 10.7%, 6.9%, 9.3%, 8.1%, 10.5%, 7.5%, and 7% variation, respectively, of the total variation in the microbial community. Furthermore, the network analysis showed that symbiotic relationships accounted for a major percentage of the microbial networks. The keystone aerobic denitrifying bacteria belonged to Comamonas, Rhodobacter, Achromobacter, Aeromonas, Azoarcus, Leptothrix_Burkholderiales, Pseudomonas, Thauera, unclassified_Burkholderiales, and unclassified_bacteria. The composition of the keystone aerobic denitrifying microbial community also exhibited significant differences (R2 = 0.4534, P &lt, 0.05) on the basis of the adonis analysis. T, STP, IEF-NH4+-N, ion-exchangeable form of nitrate (IEF-NO3--N), WAEF-NO3&minus, N, SAEF-NH4+-N, and TN were the dominant environmental factors that explained 8.4%, 6.2%, 4.6%, 5.9%, 5.9%, 4.5%, and 9.4% variation, respectively, of the total variation in the keystone aerobic denitrifying microbial community. The systematic investigation could provide a theoretical foundation for the evolution mechanism of the aerobic denitrifying microbial community in Baiyangdian Lake.

In this study, the enclosure system exhibited perfect nitrogen removal performance with in situ oxygen-enhanced indigenous aerobic denitrifying bacteria in an enclosure experiment. We explored changes in the microbial community during the nitrogen removal process using the MiSeq high-throughput sequencing technology. The results revealed a total of 7974 and 33653 operational taxonomic units (OTUs) for water and sediment systems, respectively, with 97% similarity. The OTUs were found to be affiliated with eight main phyla (Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Firmicutes, and Actinobacteria). The diversity of the enhanced system was found to be higher than that of the control system. Principal component analysis (PCA) revealed that significant spatial and temporal differences were exhibited in the microbial community during nitrogen removal in the enclosure experiment. Redundancy analysis (RDA) indicated that physical parameters (temperature, dissolved oxygen, and pH), nitrogen (total nitrogen and nitrate), functional genes (nirK and nirS), and dissolved organic carbon (DOC) were the most important factors affecting bacterial community function and composition. Lastly, the results suggested that the variation in the microbial community could be analyzed through the MiSeq high-throughput sequencing technology, which may provide technical support for future field tests. Keywords: Nitrogen removal, MiSeq high-throughput sequencing technology, In situ enclosure, RDA, Drinking water reservoir

Based on excitation emission matrix spectroscopy (EEMs) technology combined with parallel factor analysis (PARAFAC) and ultraviolet-visible (UV-vis) spectra, we analyze the spatial distribution, spectral characteristics, and sources of dissolved organic matter (DOM) in Baiyangdian Lake, China, during a winter freezing period. Results showed that the UV-vis absorption spectrum of DOM had no obvious characteristic peak, and that the variation coefficient of absorption exhibited a significant difference (

Four typical park water bodies located in the main urban area of Shijiazhuang city were selected to study the relationships between water quality and the community structure and diversity of

Here, the performance and mechanism of pollutant removal in the Zhoucun reservoir by water-lifting and aeration systems (WLAs) were explored. The hypolimnion anoxic layer disappeared and the reservoir was mixed after the WLAs were operated for approximately 35 days, providing a suitable environment for pollutant removal. Operation of the system enhanced the metabolic activity of the water microbes and their capacity for purification, which contributed to the removal of nitrogen, organic carbon, Fe, Mn, P, and S. Specifically, the total N concentration decreased from 2.55 to 0.48 mg/L, showing an 81.18% removal rate. Microbial metabolism and the diversity index increased following the operation of the WLAs in the Zhoucun Reservoir. Furthermore, the water reservoir clearly inhibited the performance of Fe, Mn, P, and S through the WLA operation, meeting the requirements for class III based on the Chinese Surface Water Environmental Quality Standard (GB3838–2002). High-throughput sequencing analysis revealed increased levels of indicator and keystone operational taxonomic units belonging to Flavobacterium, hgcI_clade, Rheinheimera, Dechloromonas, Pseudomonas, and Rhodocyclaceae, which are related to the degradation of organic carbon and removal of nitrogen and phosphorus. Moreover, total N, ammonia, total P, dissolved oxygen, temperature, and pH were the principal factors affecting the microbial community based on redundancy analysis and the Mantel test. Furthermore, network analysis showed that symbiotic relationships accounted for the major proportion of the microbial network. Our results provide a theoretical foundation for the efficiency of N removal and essential technical support for improving the self-repair capacity of water in drinking water reservoirs.

Due to global warming, some regions of Earth may face frequent and severe droughts in the future, leading to the deterioration of surface water quality. In this study, we investigated the effects of drought-induced drawdown on the water quality of the Zhoucun Reservoir, Shandong Province, East China, during the fall overturn. Field surveys were conducted during stratification (April–November) over three standard years 2012, 2013, and 2014, and over the El Nino event of 2015. Temporal and vertical variations of the physical and chemical indexes were investigated during monitoring. Results show that after the formation of stratification, the hypolimnion rapidly shifted to anaerobic conditions, with the accumulation of pollutants such as manganese (Mn) and total phosphorous (TP). Due to the extreme El Nino event in 2015, both the upper and lower metalimnion limits moved down along with the water level in summer, which resulted in the transfer of hypolimnion water to the metalimnion. In summer 2015, large amounts of pollutants were measured in the metalimnion: a phenomenon that did not occur at the same period of the standard years. At the beginning of the overturn in 2015, the water quality of the whole reservoir deteriorated when the metalimnion water shifted to the epilimnion. Mn and TP concentrations in the epilimnion reached 0.202 mg/L and 0.086 mg/L, respectively, which are significantly higher than those in the standard years. Although the tributary rivers entered the epilimnion of the reservoir during the overturn, Mn and TP concentrations of the inflow were only of 0.049–0.072 mg/L and 0.033–0.047 mg/L, respectively, indicating that these rivers were not the source of the high TP and high Mn concentrations in the epilimnion. Hence, we conclude that more attention should be paid to the metalimnion position and the vertical distribution of pollutants when studying lakes and reservoirs experiencing droughts.

© 2016 Elsevier Ltd. Indigenous aerobic denitrifiers of a reservoir system were enhanced in situ by water lifting and aeration technology. Nitrogen removal characteristics and changes in the bacterial community were investigated. Results from a 30-day experiment showed that the TN in the enhanced water system decreased from 1.08-2.02 to 0.75-0.91 mg/L and that TN removal rates varied between 21.74% and 52.54% without nitrite accumulation, and TN removal rate of surface sediments reached 41.37 ± 1.55%. The densities of aerobic denitrifiers in the enhanced system increased. Furthermore, the enhanced system showed a clear inhibition of Fe, Mn, and P performances. Community analysis using Miseq showed that diversity was higher in the in situ oxygen enhanced system than in the control system. In addition, the microbial composition was significantly different between systems. It can be concluded that in situ enhancement of indigenous aerobic denitrifiers is very effective in removing nitrogen from water reservoir systems.

Based on three-dimensional fluorescence spectra (EEMs) combined with parallel factor analysis (PARAFAC), and ultraviolet-visible (UV-Vis) spectra, we analyzed the vertical distribution and characteristics of dissolved organic matter in sediment interstitial water during the formation stage of thermal stratification in the Zhoucun Reservoir. The results show that the UV-Vis absorption coefficient varies between -400% and 400%, indicating the different properties of DOM(dissolved organic matter) at different depths. The changes of E2/E3 show that the proportion of fulvic acid in DOM increases with the stratification of the reservoir and fulvic acid accounts for the main proportion with autochthonous characteristics based on E3/E43.5 and

Based on excitation emission matrix spectroscopy (EEMs) technology combined with parallel factor analysis (PARAFAC) and UV-Vis spectra, we analyzed the spectral characteristics and sources of dissolved organic matter (DOM) in rainwater with different DOC molecular weight in summer and autumn in the Zhoucun Reservoir. The results show that the UV-Vis absorption spectrum of DOM have no notably characteristic peak and the variation coefficient of the absorption coefficient ranges between 75% and 469%, which shows the properties of DOM with different molecular weight. The changes of

In order to explore the trend and driving factors of nitrogen in the early stage of the thermal stratification in Zhoucun reservoir, the water quality indicators in main reservoir area of Zhoucun reservoir were monitored regularly form February to April (2016). Meanwhile, the fresh water and surface sediments in the sampling point were collected to study the effect of water and sediment denitrification by simulation in laboratory. The results showed that: the concentration of TN decreased from (2.28±0.09) mg·L

The differences in the resource and characteristics of DOM between Zhoucun Reservoir and Jinpen Reservoir were studied by fluorescence ultraviolet-visible (UV-vis) and excitation-emission matrix spectra combined with parallel analysis (EEMs-PARAFAC). The results showed that three fluorescent components were identified by PARAFAC model in Zhoucun Reservoir and Jinpen Reservoir, including long wave humus-like component (C1: 350/460 nm), visible fulvic-like (C2: 335/410 nm) and protein-like (C3: 260,285/360 nm). However, the fluorescence intensity and the relative proportions of DOM exhibited significant difference (

Denitrification is a major biological process that reduces nitrate to nitrogen gas (N2 or N2O). In shallow eutrophic reservoirs, this process can remove the largest portion of fixed nitrogen and play an important role in the self-purification of this ecosystem. To understand the structure of denitrifying communities in a shallow eutrophic reservoir, NirS-Type and NirK-Type denitrifier communities were explored using a MiSeq high-throughput sequencing technique. NirK and NirS are two functional marker genes for denitrification that encode copper- and cytochrome cd1-containing nitrite reductases, respectively, which catalyze the reduction of nitrite to nitric oxide. MiSeq sequencing revealed a total of 13 102 and 3490 OTUs with 97% similarity for NirS-Type and NirK-Type denitrifiers, which contained 4 and 5 phyla, and 22 and 21 genera for NirS-Type and NirK-Type denitrifiers, respectively. The ACE, Chao diversity, and Shannon richness estimates for NirS-Type denitrifiers were higher than those for NirK-Type denitrifiers. However, the Simpson richness exhibited the opposite trend. The denitrification community structure exhibited significantly seasonal variations during the whole experiment period based on the PCA, Hcluster analysis, OTUs distributions, community composition, and heat map analysis. Meanwhile, the RDA indicated that the total sediment nitrogen, aerobic denitrifiers, functional genes, denitrification rates, and temperature were critical environmental factors influencing the seasonal variation in the bacterial denitrification community.

Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20-26 °C and a dissolved oxygen concentration of 3-7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/L and that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each with no nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12 to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to 1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimental and control systems ranged from 2.8 × 10(4) to 2 × 10(7) cfu/mL and from 7.75 × 10(3) to 5.5 × 10(5) cfu/mL, respectively. The permanganate index in the experimental and control systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems.

Zhoucun reservoir is one of the major water resources in Zao Zhuang city, northern China. The seasonal distribution of surface sediment denitrification rate and enhanced performance of denitrification via water-lifting aeration technology were explored using the acetylene-inhibition technique. Surface sediment denitrification rates ranged from 2.57 ± 1.32 to 923.90 ± 86.81 nmol N2/(g dw·h), with the highest rates in November (ANOVA, p

In this paper, a novel bandpass filter (BPF) using the composite right/left-handed transmission line (CRLH-TL) theory is presented.The composite right/left-handed TL with the high-pass characters of left-handed transmission line (LH-TL) and the low-pass characters of right-handed transmission line (RH-TL) are used to construct the bandpass filter.Using this theory,we design a bandpass filter which have an obvious band pass response with a wide passband range from 5.1to 12.9GHz and a low insertion loss of less than 3.1dB. The relative bandwidth is close to 110%. Simulation using ADS demonstrated the viability of the approach.

This paper based on ANOVA (ANalysis Of VAriance) presents an investigation in the design of signal via in multilayered printed circuit boards (PCB) technology from a signal integrity point of view. Using the concept of the orthogonal array (OA), different vias physical aspect ratios have been set in the analysis. The impacts of these parameters are investigated with the help for a full-wave electromagnetic simulation soft HFSS. This study demonstrates the factors which is the most influence on the signal integrity.

High-speed signal connector has become a key factor of the signal transmission quality in telecommunications and data communications system. Signal integrity of connector is an inevitable problem. This paper based on the theory of differential transmission lines and Multimode S-Parameters, analyzed the USB3.0 connector signal integrity. And use 3D simulation software CST to build model and analyze the relationship of signal integrity and connectors geometry.

In this paper, a highly-selective filter based on the composite right/left-handed transmission line (CRLH-TL) theory is presented .It is realized by replacing the traditional shunt inductive loading with a series LC resonator to ground. An attenuation-pole can be introduced by replacing the shorted-stub with a open stub.Simulation using ADS and HFSS of a compact highly-selective filter demonstrated the viability of the approach.

The buffer setting and management mechanism in Critical chain method was combined with practical progress vanguard line in this paper. Then the information statistical and analysis methods of project schedule was given, and the methods are applied in project scheduling management of warship scheduled repair. With the application analysis in maintenance project shows that this methods can identify the activity chain which really lead to the lag of project scheduling. This shows that the method was given in this paper presents an applicable value for actual warship scheduled repair project scheduling management. CLC number: U672 Document id code: A

In order to reveal the seasonal stratification and the response of water quality of a temperate reservoir Zhoucun Reservoir in North of China. The physical, chemical and phytoplankton indexes were continuously monitored from July 2014 to June 2015. The results showed that the thermal stratification was monomictic, which lasted from April to October. The thermal stratification played an important role in the change of water environment. The hypoxia in the bottom water caused hy thermal stratification led to the release of nutrients and reductants from sediment. During the stratification period, the mean concentrations of total nitrogen, total phosphorus, manganese and sulfide were 1.18, 0.11, 0.47 and 0.48 mg · L⁻¹, respectively. The vertical distribution of phytoplankton was significantly influenced by water temperature stratification. During the thermal stratification period, phytoplankton abundance was higher and the average phytoplankton ahundance was 16.35 x 10⁶ cells · L⁻¹ in the upper water of the reservoir, while remained at low levels at the bottom.

Sediment pollution characteristics, in situ sediment release potential, and in situ inhibition of sediment release were investigated in a drinking water reservoir. Results showed that organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) in sediments increased from the reservoir mouth to the main reservoir. Fraction analysis indicated that nitrogen in ion exchangeable form and NaOH-extractable P (Fe/Al-P) accounted for 43% and 26% of TN and TP in sediments of the main reservoir. The Risk Assessment Code for metal elements showed that Fe and Mn posed high to very high risk. The results of the in situ reactor experiment in the main reservoir showed the same trends as those observed in the natural state of the reservoir in 2011 and 2012; the maximum concentrations of total OC, TN, TP, Fe, and Mn reached 4.42mg/L, 3.33mg/L, 0.22mg/L, 2.56mg/L, and 0.61mg/L, respectively. An in situ sediment release inhibition technology, the water-lifting aerator, was utilized in the reservoir. The results of operating the water-lifting aerator indicated that sediment release was successfully inhibited and that OC, TN, TP, Fe, and Mn in surface sediment could be reduced by 13.25%, 15.23%, 14.10%, 5.32%, and 3.94%, respectively.

Sulfate-reducing bacteria (SRB) play an important role in the sediments of bay areas, estuaries, and lakes. However, information regarding the genetic diversity of SRB in the sediments of drinking water reservoirs is scarce. In this study, we collected sediment samples from different sites in the Zhou Cun drinking water reservoir between April and June 2012. To explore the genetic diversity of SRB, we used the most-probable-number (MPN) method, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), and a cloning approach. The average content of acid-volatile sulfide at the deepest sampling site was 205.87 μg/g sediment. This result is often associated with a large abundance of SRB in the associated sediment. The highest MPN estimate (1.15 x 10(5) cells/g sediment) was detected in May at the deepest sampling site. The PCR-DGGE fingerprints of SRB based on the dissimilatory sulfite reductase beta subunit (dsrB) gene varied according to the different sampling sites and dates. The highest abundance of SRB in the sediments was predominantly found at the deepest sampling sites, as expected from the acid-volatile sulfide content. The dominant species were Desulfobulbus sp, Desulfobacterium sp, and uncultured sulfate-reducing bacteria. Redundancy analysis revealed that organic matter and the concentrations of nitrogen and phosphorus in the sediments were significantly correlated with the diversity of SRB communities present. The results of this study provide a better understanding of the sulfate-reducing microbial species in the sediments of the Zhou Cun drinking water reservoir.

Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This species exhibits a periplasmic nitrate reductase gene (napA). Its specific growth rate was 0.22 h−1. Obvious denitrification and perfect nitrogen removal performances occurred when cultured in nitrate and nitrite mediums, at rates of 75.53% ± 1.69% and 58.65% ± 0.61%, respectively. The ammonia removal rate reached 44.12% ± 1.61% in ammonia medium. Zoogloea sp. N299 was inoculated into sterilized and unsterilized reservoir source waters with a dissolved oxygen level of 5–9 mg/L, pH 8–9, and C/N 1.14:1. The total nitrogen removal rate reached 46.41% ± 3.17% (sterilized) and 44.88% ± 4.31% (unsterilized). The cell optical density suggested the strain could survive in oligotrophic drinking water reservoir water conditions and perform nitrogen removal. Sodium acetate was the most favorable carbon source for nitrogen removal by strain N299 (p &lt, 0.05). High C/N was beneficial for nitrate reduction (p &lt, 0.05). The nitrate removal efficiencies showed no significant differences among the tested inoculums dosage (p &gt, 0.05). Furthermore, strain N299 could efficiently remove nitrate at neutral and slightly alkaline and low temperature conditions. These results, therefore, demonstrate that Zoogloea sp. N299 has high removal characteristics, and can be used as a nitrogen removal microbial inoculum with simultaneous aerobic nitrification and denitrification in a micro-polluted reservoir water ecosystem.

In this paper, a novel composite right/left handed transmission line (TL) structure is proposed. The CRLH TL has high-pass property at lower frequencies and low-pass property at higher frequencies, thus constructs a bandpass filter. Lumped or quasi-lumped microwave components are introduced to satisfy the necessity of the filter. Simulation using ADS and HFSS demonstrated the viability of the approach.

The frequency characteristics of the microstrip line with DGS are simulated by means of 3-D field analysis, and its equivalent circuit and equivalent parameters extraction are analyzed. Then the influences of C shape and the material permittivity on frequency characteristic are discussed using the simulation with Taguchi method.

This paper describes a new electromagnetic optimization technique using Taguchi's method and applies it to design differential-via in multilayered printed circuit boards (PCB). Taguchi's method was developed on the basis of the orthogonal array (OA) concept, which offers systematic and efficient characteristics. Using the concept of the analysis of variance, different via's physical aspect ratios have been set in the analysis. The impacts of these parameters are investigated with the help for a full-wave electromagnetic simulation soft HFSS. The Taguchi method can quickly converge to the desired design since it takes less computational resource. And the Taguchi's method is easy to implement and efficient to reach the optimum solutions.

In manufacturing, the dielectric constant of High-speed PCB's dielectric material is difficult to control in a certain value. So the dielectric constant is uncontrollable factor. The paper carries out a comprehensive study of the impacts of the different dielectric constant in various differential-via design parameters on signal integrity (SI) using a full-wave electromagnetic simulator (HFSS) and DOE of Taguchi method. To optimize the differential-via's parameters so that there is small effect on SI in different dielectric material.