Green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in greenhouse with high temperature

Xiaodong Wang,Xingguo Liu1,Boqiang Qin,Zhaojun Gu,Hao Xu,Hao Zhu,Guofeng Cheng,Huang Liu 한국생태학회 2015 Journal of Ecology and Environment Vol.38 No.3

In order to understand the mechanisms of conversion between different algal dominance, an experiment was performed in a greenhouse from 22 June to 10 July 2011. The experiment included a treatment group subjected to three instances of nutrient enrichment and a control with no nutrient enrichment. The initial water was dominated by Ankistrodesmus of Chlorophyta. The average water temperature at 08:30 h and 14:00 h during the experiment was 31.6°C and 34.6°C, respec¬tively. The results showed that the total nitrogen (TN), total phosphorus (TP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), and soluble reactive phosphorus (SRP) concentrations in the treatment were significantly higher than in the control (P < 0.05). However, the TN/TP and DTN/DTP in the control was higher than in the treatment (P < 0.05). The dominant algae in the control did not change during the experiment, while the dominant algae in the treat¬ment switched to Planktothrix of Cyanophyta on day 9. The chlorophyll a (Chl-a), wet weight of all algae, wet weight of Cyanophyta, and percentage of Cyanophyta in the control were all significantly lower than in the treatment (P < 0.05). Amounts of zooplankton, especially rotifers, were present at the end of the experimental period. The density of rotifers between the control and treatment was not significantly different (P > 0.05), while the copepod density in the treatment was higher than in the control (P < 0.05). We conclude that green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in a greenhouse with elevated temperature

ONE-STEP AND CONTROLLABLE SELF-ASSEMBLY OF Au/TiO2/CARBON SPHERES TERNARY NANOCOMPOSITES WITH A NANOPARTICLE MONOSHELL WALL

XIAODONG HAO,YUXIN ZHANG,JIA LIU,MENG DONG,MING HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.4

In this work, stable and well dispersed colloidal Au/TiO2 binary nanoparticles (NPs) were synthesized initially. Meanwhile, they were immobilized simultaneously on colloidal carbon spheres (CSs), one of popular hard templates, to prepare hybrid self-assembly nanostructures. The morphology and crystal structure of these nanocomposites (NCs) were characterized by ¯eld emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), powder X-ray di®raction (XRD), thermogravimetric (TGA) and N2 sorption analysis. By controlling the NPs size, ratio of Au/TiO2 NPs, process temperature and time, and concentration of surfactants (e.g., MPA), Au/TiO2@CSs NCs could be tailored into core-shell nanostructures with various surface coverages of Au NPs and/or TiO2NPs. Interestingly, hollow spheres with a binary-nanoparticle monoshell could be achieved by calcinations of typical Au/TiO2@CSs NCs. In principle, these novel hybrid nanostructures with controllable functionality and high-surfacearea traits could be very promising photocatalysts for waste water treatment.

Green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in greenhouse with high temperature

Wang, Xiaodong,Liu, Xingguo,Qin, Boqiang,Gu, Zhaojun,Wu, Zongfan,Xu, Hao,Zhu, Hao,Cheng, Guofeng,Liu, Huang The Ecological Society of Korea 2015 Journal of Ecology and Environment Vol.38 No.3

In order to understand the mechanisms of conversion between different algal dominance, an experiment was performed in a greenhouse from 22 June to 10 July 2011. The experiment included a treatment group subjected to three instances of nutrient enrichment and a control with no nutrient enrichment. The initial water was dominated by Ankistrodesmus of Chlorophyta. The average water temperature at 08:30 h and 14:00 h during the experiment was $31.6^{\circ}C$ and $34.6^{\circ}C$, respectively. The results showed that the total nitrogen (TN), total phosphorus (TP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), and soluble reactive phosphorus (SRP) concentrations in the treatment were significantly higher than in the control (P < 0.05). However, the TN/TP and DTN/DTP in the control was higher than in the treatment (P < 0.05). The dominant algae in the control did not change during the experiment, while the dominant algae in the treatment switched to Planktothrix of Cyanophyta on day 9. The chlorophyll a (Chl-a), wet weight of all algae, wet weight of Cyanophyta, and percentage of Cyanophyta in the control were all significantly lower than in the treatment (P < 0.05). Amounts of zooplankton, especially rotifers, were present at the end of the experimental period. The density of rotifers between the control and treatment was not significantly different (P > 0.05), while the copepod density in the treatment was higher than in the control (P < 0.05). We conclude that green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in a greenhouse with elevated temperature.

Fermentation Characteristics and Lactic Acid Bacteria Succession of Total Mixed Ration Silages Formulated with Peach Pomace

Xiaodong Hu,Wei Hao,Huili Wang,Tingting Ning,Mingli Zheng,C.C. Xu 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.4

The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages.

Dolomites of the Yingshan Formation in the Tazhong Low Rise, Tarim Basin: dolomitisation and reformation model

Xiaodong Lan,Hao Liu,Xiuxiang Lü,Baohua Lan 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.1

The Tazhong Low Rise has abundant hydrocarbon resources in the Yingshan Formation of Lower Ordovician, where dolomite has been demonstrated to be a significant target for carbonate hydrocarbon exploration. Using optical observation and geochemical tests, three types of dolomite can be used as replacement and cement products. D1 dolomite is silt or fine crystalline, and has the fluid inclusions of low Th (71.4 °C) and corresponding salinity (9.89 wt% NaCl). In addition, geochemical data indicate that D1 dolomite was formed with shallow burial fluids and was intensely affected by weathering karst in the middle Ordovician, which served as a mixing-zone for dolomitisation. D2 dolomite of medium-coarse grain has similar geochemical characteristics as D1 dolomite except that it has higher diagenetic temperature and negative δ18O, suggesting that it generally developed in a deep burial environment. The cathodoluminescence showed two zonal structures in D1 dolomite, while at least three zonal structures in D2 dolomite were influenced by multiple burial diagenetic fluids. The D3 dolomite has a saddle structure with medium-coarse crystalline, high contents of Mn, Ba, Fe, and Sr, high Th (140 °C), high salinity (20.36 wt% NaCl), and negative δ18O (–10.1 to –7.8‰). Meanwhile, D3 dolomite is distributed near faults and fractures that are accompanied by hydrothermal minerals and is obviously influenced by hydrothermal fluids.

Experimental investigation on a freestanding bridge tower under wind and wave loads

Xiaodong Bai,Anxin Guo,Hao Liu,Wenli Chen,Gao Liu,Tianchen Liu,Shangyou Chen,Hui Li 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.5

Long-span cross-strait bridges extending into deep-sea waters are exposed to complex marine environments. During the construction stage, the flexible freestanding bridge towers are more vulnerable to environmental loads imposed by wind and wave loads. This paper presents an experimental investigation on the dynamic responses of a 389-m-high freestanding bridge tower model in a test facility with a wind tunnel and a wave flume. An elastic bridge model with a geometric scale of 1:150 was designed based on Froude similarity and was tested under wind-only, wave-only and wind-wave combined conditions. The dynamic responses obtained from the tests indicate that large deformation under resonant sea states could be a structural challenge. The dominant role of the wind loads and the wave loads change according to the sea states. The joint wind and wave loads have complex effects on the dynamic responses of the structure, depending on the approaching direction angle and the fluid-induced vibration mechanisms of the waves and wind

Fermentation Characteristics and Lactic Acid Bacteria Succession of Total Mixed Ration Silages Formulated with Peach Pomace

Hu, Xiaodong,Hao, Wei,Wang, Huili,Ning, Tingting,Zheng, Mingli,Xu, Chuncheng Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.4

The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages.

Improved direct torque control strategy for reducing torque ripple in switched reluctance motors

Fan Yang,Hao Chen,Vitor Pires,Joao Martins,Yassen Gorbounov,Xiaodong Li,Mohamed Orabi 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

To reduce the torque ripple of a switched reluctance motor (SRM), this paper proposed a direct torque optimization scheme. To force the torque to better track the reference torque, the proposed method abolished the torque hysteresis control and a fuzzy controller was adopted to quantitatively analyze the difference between the reference torque and measured torque. Therefore, the torque reference factor that represents the torque under different conditions can be obtained, and the system should be controlled by different voltage vectors with different output torque capabilities at different torque reference factor values. In this way, the torque can better track the given torque. At the same time, the existing sectors were optimized in this paper. Under optimized sectors, the adopted direct torque control (DTC) scheme can drive the SRM better. To verify the effectiveness of the proposed scheme, it is compared with the current chop control (CCC) strategy and the traditional DTC control strategy on a 12/8 three-phase SRM by simulations and experiments. The obtained results show that the proposed method can effectively reduce the torque ripple of the SRM.

Preparation of decorative slag glass-ceramics and research on the solidification of heavy metals

Yang Tang,Xiaodong Hao,Zhenxiang Fang,Xinyu Bai,Guangyu Wang,Hongxia Zhang,Leibo Deng,Hua Chen,Ming Zhao,Yongsheng Du 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

Glass-ceramics with different CuO additions were prepared with Fe2O3 and Cr2O3 as composite nucleating agents, rare earthcontainingblast furnace slag (REBFS) as the main raw material. The existence state and stability of heavy metals Cu, Mn andCr in glass-ceramics were investigated. The results showed that Cr ions contributed to the generation of spinel phase, whileCu ions and Mn ions can enter the spinel crystal and exist stably, which indicated that there was a synergistic solidificationof Cu, Mn and Cr. The depolymerization effect of the copper ions contributed to the transformation of the crystal morphologyfrom dendrites to spherulites. Moreover, the increase in CuO contents promoted glass-ceramics from green to copper red. Based on the leaching experimental data analysis of heavy metals in glass-ceramics, the leaching concentration of heavy metalsCu, Cr and Mn were much lower than the standard leaching toxicity limit of hazardous waste (GB5085.3–2007, China). Theresults showed that the conversion of REBFS into environmentally friendly glass-ceramics can realize solid waste resourceutilization.

Mechanical Properties of (Ce + Yb) Modified in situ TiB2/Al-Si Matrix Composites Enhanced via Thermal Deformation Combined with Heat Treatment

Mingkun Qiu,Wenru Hu,Hao Liu,Yafei Pang,Xiaodong Du 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.10

In the current work, the microstructure evolution and mechanical properties of (Ce + Yb) modified in situ TiB2/Al-Si matrix composite were systematically investigated by thermal deformation at strain rates of 0.0005–0.0125 s− 1 and temperatures of 250–450 °C. The enhanced strength and plasticity of the composite have a good correlation with the microstructure evolution under different thermal deformation parameters. The obtained results indicated that under the hot deformation parameters of strain rate of 0.0025 s− 1 and deformation temperature of 250 °C, the defects of micropores can be reduced or even eliminated and improved the density of the composite. The coarse α-Al grains, eutectic Si and Fe-rich phases and undissolved primary (Ce + Yb)-containing intermetallics were significantly refined under high shear stress. At the same time, the distribution of in-situ synthesized submicron TiB2 particles in the Al matrix tends to be more uniform. The substructures such as high density dislocations and low angle grain boundaries were introduced under the thermal deformation of 250 °C/0.0025 s− 1, which provided the necessary conditions for the formation of recrystallized grains that are less likely to overgrow and further promoted the aging precipitation of nano-strengthening precipitates. Finally, the UTS, YS and elongation of the composite reached the maximum values of 385 MPa, 316 MPa and 9.6% respectively, which were 60.4%, 85.9% and 45.5% higher than the as-cast and undeformed composite.