Regulating Characteristics Analysis of Boiler Feed-water Pump when 600MW Unit Sliding-pressure Operating

AbstractAccording to the characteristics of utility-type generator set in variable load sliding-pressure operation, the paper comprehensively analyzes the features of feed-water system, in which variable-speed main feed-water and power frequency booster-pump connect first in series and then in parallel. It puts emphasis on fitting characteristics equation of feed-water pump under different operations, determining characteristics of feed-water pipeline under sliding-pressure operation, corresponding resistance coefficient, and finally deducing the equation of lift, efficiency and rotating speed when different loads and different sliding-pressures are adapted only by main feed-water pump variable speed adjusting. It takes one power plant 600MW supercritical unit for example to compare the energy consumption of different operation modes, and thus puts forward a more suitable operation mode under different loads, providing theoretical basis for the practical application of project

2,4-Dibromo-6-{(E)-[(R)-1-phenyl­ethyl]imino­meth­yl}phenol

In the title Schiff base, C15H13Br2NO, the benzene and phenyl rings form a dihedral angle of 75.18 (13)°. The N=C bond length of 1.263 (6) Å is shorter than of the N—C bond [1.476 (5) Å], indicating a double bond. In the crystal, there is some pseudosymmetry. This occurs because most of the two mol­ecules are centrosymmetrically related. The mol­ecular structure is stabilized by intra­molecular O—H⋯N hydrogen bonds

Electronic Structures of Graphene Layers on Metal Foil: Effect of Point Defects

Here we report a facile method to generate a high density of point defects in graphene on metal foil and show how the point defects affect the electronic structures of graphene layers. Our scanning tunneling microscopy (STM) measurements, complemented by first principle calculations, reveal that the point defects result in both the intervalley and intravalley scattering of graphene. The Fermi velocity is reduced in the vicinity area of the defect due to the enhanced scattering. Additionally, our analysis further points out that periodic point defects can tailor the electronic properties of graphene by introducing a significant bandgap, which opens an avenue towards all-graphene electronics.Comment: 4 figure

Effectiveness of erythropoietin supplementation against chronic heart failure with anemia, and its effect on serum hypersensitive C reaction protein, homocysteic acid and Btype natriuretic peptide

Purpose: To study the effectiveness of exogenous erythropoietin (EPO) against chronic heart failure (CHF) with anemia, and its effect on serum hypersensitive C reaction protein (hs-CRP), homocysteic acid (Hcy ) and B-type natriuretic peptide (BNP).Methods: A total of 136 patients suffering from CHF with anemia from June 2015 to June 2017 were randomly divided into observation group (n = 68) and control group (n = 68). On the basis of conventional anti-heart failure therapy, the control group received oral ferrous sulfate tablets, while the observation group received oral ferrous sulfate tablets combined with EPO subcutaneous injection. Blood indices, cardiac function and serology were determined and tested in all patients before treatment, and at 4 months after treatment.Results: After treatment, hemoglobin (Hb), hematocrit (HCT), red blood cell (RBC), blood platelet count (PLT) and serum iron were significantly higher than those before treatment in the two groups; the levels in the observation group were significantly higher than those in control group (p <0.05). Following treatment, left ventricular ejection fraction (LVEF), and 6-minute walking distance in the observation group were significantly higher than those in the control group, while end-diastolic dimension (LVEDD), end-systolic dimension (LVESD) and cardiac functional grading in the observation group were significantly lower than those in the control group (p < 0.05). After treatment, hs-CRP, Hcy and BNP were significantly lower than pre-treatment values in the two groups, while the values for the observation group were significantly lower than those of control group (p <0.05). Correlation analysis showed that LVEF and Hb were negatively correlated with hs-CRP, Hcy and BNP (p <0.05).Conclusion: Serum hs-CRP, Hcy and BNP are involved in the occurrence and progression of CHF with anemia. Exogenous EPO can effectively improve anemia and cardiac function in these patients.Keywords: Erythropoietin, Chronic heart failure, Anemia, C-reaction protein, B-type natriuretic peptid

Diosgenin inhibits cell proliferation of primary human thyrocytes via downregulation of PI3K/Akt signaling pathway

Purpose: To determine the potential influence of diosgenin on proliferation of human thyrocytes and its possible mechanism.Methods: Primary human thyrocytes were cultured and treated with diosgenin at various time intervals. Anti-proliferative activity was determined by MTT assay. Cell proliferation was evaluated by EdU assay while cell cycle was analyzed using fluorescence-activated cell sorting (FACS) method. Protein expression of p21 (CIP1), p27 (KIP1), cyclins, protein kinase B (Akt), phosphatidylinositol 3 kinase (PI3K) and p-Akt was determined by the western blot.Results: Diosgenin inhibited proliferation of primary human thyrocytes and caused G0/G1 arrest in a concentration-dependent manner. It also downregulated cyclin D1 and phosphorylation of PI3K and Akt, but upregulated p21 and p27.Conclusion: Inhibition of proliferation of primary human thyrocytes by diosgenin occurs viadownregulation of PI3K/Akt signaling pathway. Therefore, diosgenin can be developed as a potential drug for the treatment of thyroid disease.Keywords: Diosgenin, Proliferation, Primary human thyrocytes, PI3K/Akt signaling pathwa

Power-Law Decay of Standing Waves on the Surface of Topological Insulators

We propose a general theory on the standing waves (quasiparticle interference pattern) caused by the scattering of surface states off step edges in topological insulators, in which the extremal points on the constant energy contour of surface band play the dominant role. Experimentally we image the interference patterns on both Bi$_2$Te$_3$ and Bi$_2$Se$_3$ films by measuring the local density of states using a scanning tunneling microscope. The observed decay indices of the standing waves agree excellently with the theoretical prediction: In Bi$_2$Se$_3$, only a single decay index of -3/2 exists; while in Bi$_2$Te$_3$ with strongly warped surface band, it varies from -3/2 to -1/2 and finally to -1 as the energy increases. The -1/2 decay indicates that the suppression of backscattering due to time-reversal symmetry does not necessarily lead to a spatial decay rate faster than that in the conventional two-dimensional electron system. Our formalism can also explain the characteristic scattering wave vectors of the standing wave caused by non-magnetic impurities on Bi$_2$Te$_3$.Comment: 4 pages, 3 figure

Aqua­(2,2′-bipyrimidine-κ2 N,N′)(succin­ato-κ2 O 1,O 4)copper(II) dihydrate

In the crystal structure of the title compound, [Cu(C4H4O4)(C8H6N4)(H2O)]·2H2O, the CuII atom is chelated by a 2,2′-bipyrimidine (bpm) ligand and a succinate anion in the basal plane; a water mol­ecule in the apical position completes the slightly distorted square-pyramidal coordination geometry. Another carboxyl­ate O atom from an adjacent complex is located in the opposite apical direction, with a Cu⋯O distance of 2.706 (3) Å, and is not considered as a bridging atom. Extensive O—H⋯O and O—H⋯N hydrogen bonding is present in the crystal structure

Testing Lorentz symmetry with space-based gravitational-wave detectors

Lorentz symmetry (LS), one of the most fundamental physical symmetries, has been extensively studied in the context of quantum gravity and unification theories. Many of these theories predict a LS violation, which could arise from the discreteness of spacetime, or extra dimensions. Standard-model extension (SME) is an effective field theory to describe Lorentz violation whose effects can be explored using precision instruments such as atomic clocks and gravitational-wave (GW) detectors. Considering the pure-gravity sector and matter-gravity coupling sector in the SME, we studied the leading Lorentz-violating modifications to the time delay of light and the relativistic frequency shift of the clock in the space-based GW detectors. We found that the six data streams from the GW mission can construct various combinations of measurement signals, such as single-arm round-trip path, interference path, triangular round-trip path, etc. These measurements are sensitive to the different combinations of SME coefficients and provide novel linear combinations of SME coefficients different from previous studies. Based on the orbits of TianQin, LISA, and Taiji missions, we calculated the response of Lorentz-violating effects on the combinations of the measurement signal data streams. Our results allow us to estimate the sensitivities for SME coefficients: $10^{-6}$ for the gravity sector coefficient $\bar{s}^{TT}$, $10^{-6}$ for matter-gravity coupling coefficients $(\bar{a}^{(e+p)}_{\text{eff}})_{T}$ and $\bar{c}^{(e+p)}_{TT}$, and $10^{-5}$ for $(\bar{a}^{n}_{\text{eff}})_{T}$ and $\bar{c}^{n}_{TT}$.Comment: 17 pages, 10 figure

Aqua­bis(2-amino-1,3-thia­zole-4-acetato-κ2 O,N 3)nickel(II)

In the crystal structure of the title compound, [Ni(C5H5N2O2S)2(H2O)], the NiII cation is located on a twofold rotation axis and chelated by two 2-amino-1,3-thia­zole-4-acetate (ata) anions in the basal coordination plane; a water mol­ecule located on the same twofold rotation axis completes the distorted square-pyramidal coordination geometry. Inter­molecular O—H⋯O and N—H⋯O hydrogen bonding, as well as π–π stacking between parallel thia­zole rings [centroid–centroid distance 3.531 (8) Å], helps to stabilize the crystal structure