Study on Multi-scale Unit Commitment Optimization in the Wind-Coal Intensive Power System

Xi YE,Ying QIAO,Zongxiang LU,Yong MIN,Ningbo Wang 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units’ on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

Research on Enhancing the Corrosion Resistance of Concrete In a MgSO 4 Corrosive Environment Using CTF Synergist

Xi Wang,Hongxia Qiao,Yunsheng Zhang,Wenhua Zhang,Cuizhen Xue,Mubita Majory Mundia,Lei Zhang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

Concrete structure is easy to be damaged by corrosion in natural environment. In order to find a new way to improve the corrosion resistance of concrete. In this paper, the effect of Coal Tar Fuel (CTF) synergist on the corrosion resistance of concrete was analyzed by using MgSO4solution with concentration of 5% as corrosion medium. The change rule of concrete pore structure was studied. And the performance of concrete interfacial transition zone (ITZ) is studied. Finally, the effect of CTF synergist on hydration reaction of cementitious materials was revealed. The results show that the addition of 0.7% CTF synergist can significantly enhance the corrosion resistance of concrete, even with 10% reduction in cement dosage. After 28 days of being cured under this dosage, there is 13.54% increase in the proportion of pores with a diameter less than 100 μm and a 5.36% decrease in the proportion of pores with a diameter greater than 600 μm. Meanwhile, the microhardness of ITZ increases by 41.14%, while the width of ITZ decreases by 12.5%. Additionally, there is a reduction in the maximum crack width at the interface between ITZ and aggregate by 1.8 μm. The exothermic reaction of the cementitious material during hydration is more pronounced when the hydration time exceeds one hour.

Effects of Glucagon-Like Peptide-2-Expressing Saccharomyces cerevisiae Not Different from Empty Vector

( Xi Zhong ),( Guopeng Liang ),( Lili Cao ),( Qi Qiao ),( Zhi Hu ),( Min Fu ),( Hong Bo ),( Qin Wu ),( Guanlin Liang ),( Zhongwei Zhang ),( Lin Zhou ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.10

Saccharomyces cerevisiae (S. cerevisiae) and glucagon-like peptide-2 (GLP-2) have been employed to improve the intestinal development of weaned animals. The goal of this study was to determine whether either exogenous S. cerevisiae or GLP-2 elicits major effects on fecal microbiotas and cytokine responses in weaned piglets. Ninety-six piglets weaned at 26 days were assigned to one of four groups: 1) Basal diet (Control), 2) empty vector-harboring S. cerevisiae (EV-SC), 3) GLP-2-expressing S. cerevisiae (GLP2-SC), and 4) recombinant human GLP-2 (rh-GLP2). At the start of the post-weaning period (day 0), and at day 28, fecal samples were collected to assess the bacterial communities via sequencing the V1-V2 region of the 16SrRNA gene, and piglets’ blood was also sampled to measure cytokine responses (i.e., IL-1β, TNF-α, and IFN-γ). This study revealed that, on the one hand, although S. cerevisiae supplementation did not significantly alter the growth of weaned piglets, it induced increases in the relative abundances of two core genera (Ruminococcaceae_norank and Erysipelotrichaceae_norank) and decreases in the relative abundances of two other core genera (Lachnospiraceae_norank and Clostridiale_norank) and cytokine levels (IL-1β and TNF-α) (p < 0.05, Control vs EV-SC; p < 0.05, rh-GLP2 vs GLP2-SC). On the other hand, GLP-2 supplementation had no significant influence on fecal bacterial communities and cytokine levels, but it produced better body weight and average daily gain (p < 0.05, Control vs EV-SC; p < 0.05, rh-GLP2 vs GLP2-SC). Therefore, altered fecal microbiotas and cytokine response effects in weaned piglets were due to S. cerevisiae rather than GLP-2.

Study on Multi-scale Unit Commitment Optimization in the Wind-Coal Intensive Power System

Ye, Xi,Qiao, Ying,Lu, Zongxiang,Min, Yong,Wang, Ningbo The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units' on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

BERGMAN SPACES, BLOCH SPACES AND INTEGRAL MEANS OF p-HARMONIC FUNCTIONS

Fu, Xi,Qiao, Jinjing Korean Mathematical Society 2021 대한수학회보 Vol.58 No.2

In this paper, we investigate the properties of Bergman spaces, Bloch spaces and integral means of p-harmonic functions on the unit ball in ℝn. Firstly, we offer some Lipschitz-type and double integral characterizations for Bergman space ��kγ. Secondly, we characterize Bloch space ��αω in terms of weighted Lipschitz conditions and BMO functions. Finally, a Hardy-Littlewood type theorem for integral means of p-harmonic functions is established.

A conceptual thermal actuation system driven by interface tension of nanofluids

Xu, Baoxing,Qiao, Yu,Park, Taehyo,Tak, Moonho,Zhou, Qulan,Chen, Xi Royal Society of Chemistry 2011 Energy & environmental science Vol.4 No.9

<P>In a system containing nanoporous materials and liquids, the well-known thermo-capillary effect can be amplified by the ultralarge specific surface area of the nanopores. With appropriate temperature change, the relative wetting–dewetting transition can cause the liquid to flow in or out of the nanopores, and part of the thermal energy is converted to significant mechanical output. A conceptual design of such a thermal actuation/energy conversion/storage system is investigated in this paper, whose working mechanism, <I>i.e.</I> the thermally dependent infiltration behaviors of liquids into nanopores, is analyzed using molecular dynamics simulations. The fundamental molecular characteristics, including the density profile, contact angle, and surface tension of the confined liquid molecules, are examined in considerable detail. The influences of pore size, solid phase and liquid species are elucidated, which couple with the thermal effect. The energy density, power density, and efficiency of the thermal actuation system are evaluated. An infiltration experiment on a zeolite/water system is performed to qualitatively validate these findings.</P> <P>Graphic Abstract</P><P>We design a thermally actuated system using nanofluids with high energy and power densities. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1ee01405f'> </P>

Effect of Electric Field on Liquid Infiltration into Hydrophobic Nanopores

Xu, Baoxing,Qiao, Yu,Zhou, Qulan,Chen, Xi American Chemical Society 2011 Langmuir Vol.27 No.10

<P>Understanding the variation of nanofluidic behavior in the presence of an external electric field is critical for controlling and designing nanofluidic devices. By studying the critical infiltration pressure of liquids into hydrophobic nanopores using molecular dynamics (MD) simulations and experiments, important insights can be gained on the variation of the effective liquid–solid interfacial tension with the magnitude and sign of electric field, as well as its coupling with the pore size and the solid and liquid species. It is found that the effective hydrophobicity reduces with the increase of electric intensity and/or pore size, and the behavior is asymmetric with respect to the direction of the electric field. The underlying molecular mechanisms are revealed via the study of the density profile, contact angle, and surface tension of confined liquid molecules.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2011/langd5.2011.27.issue-10/la200477y/production/images/medium/la-2011-00477y_0014.gif'></P>

Secretory Expression and Characterization of an Acidic Endo-Polygalacturonase from Aspergillus niger SC323 in Saccharomyces cerevisiae

( Huoxiang Zhou ),( Xi Li ),( Mingyue Guo ),( Qingrui Xu ),( Yu Cao ),( Dairong Qiao ),( Yi Cao ),( Hui Xu ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.7

The endo-polygalacturonase gene (endo-pgaA) was cloned from DNA of Aspergillus niger SC323 using the cDNA synthesized by overlapping PCR, and successfully expressed in Saccharomyces cerevisiae EBY100 through fusing the α-factor signal peptide of yeast. The fulllength cDNA consists of 1,113 bp and encodes a protein of 370 amino acids with a calculated molecular mass of 38.8 kDa. After induction by galactose for 48 h, the activity of recombinant endo-PgaA in the culture supernatant can reach up to 1,448.48 U/mg. The recombinant protein was purified to homogeneity by ammonium sulfate precipitation and gel filtration column chromatography and subsequently characterized. The optimal pH and temperature of the purified recombinant enzyme were 5.0 and 50°C, respectively. The Michaelis-Menten constant (Km) and maximal velocity (Vmax) of the enzyme for pectin were 88.54 μmol/ml and 175.44 μmol/mg/min, respectively. The enzyme activity was enhanced by Ca2+, Cu2+, and Na+, and strongly inhibited by Pb2+ and Mn2+. The pectin hydrolysates were mainly galacturonic acid and other oligo-galacturonates. Therefore, these characteristics suggest that the recombinant endo-PgaA may be of potential use in the food and feed industries.

Effects of the Environment and Temperature on the Tribological Behavior of TiZrHfNbTa Refractory High-Entropy Alloy

Qing Zhao,Xi Jin,Xiao hui Shi,Hui jun Yang,Min Zhang,Junwei Qiao 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.8

The tribological behavior of TiZrHfNbTa refractory high-entropy alloy (RHEA) sliding against Si3N4ball was investigatedin the air, deionized water and seawater at room temperature as well as under dry condition at high temperature. The resultsshowed that the TiZrHfNbTa RHEA was composed of single BCC phase. The wear rate in air, deionized water and seawaterreached the maximum value of 3.02 × 10−4 mm3/(Nm), 2 × 10−4 mm3/(Nm) and 3.18 × 10−4 mm3/(Nm) at 10 N, respectively. Moreover, the wear rate in deionized water was much lower than that in air, while the wear rate in seawater was close to thatin air. The wear mechanisms were all transitioned from the abrasive wear to adhesive wear with increasing the normal load. At high temperature, the wear rate increased first and then decreased, reached the maximum value of 2.04 × 10–4 mm3/(Nm)at 500 ℃. In addition, oxidation occurred at 400 ℃. The wear mechanism changed from the abrasive wear to oxidation wearat high temperature.

Synthesis and In Vitro Cytotoxicity of Cis-[Pt(NH3)(NH2OH)Cl2]

Qing-Song Ye,Xi-Zhu Chen,Yao Yu,Qiao-Wen Chang,Shu-Qian Hou,Wei-Ping Liu 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.6

A novel mixed NH3/NH2OH platinum(II) complex cis-[Pt(NH3)(NH2OH)Cl2] was synthesized and characterized by elemental analysis, FAB-MS, FT-IR and 1H NMR spectroscopy. This complex was determined to have a good water-solubility and satisfactory stability. The pertinent complex was evaluated for its in vitro cytotoxicity against 3AO, HCT-116, LNcap, A549/ATCC and SGC-7901 human carcinoma cell lines. It shows appreciable cytotoxic activity that is comparable with cisplatin and is much more active than carboplatin.