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Effects of Vibration Acceleration on Stress Deformation, Microstructures and Properties of Fe314 Alloy Fabricated by Plasma Additive Manufacturing

期刊: CHINA SURFACE ENGINEERING, 2019; 32 (5)

Vibration was applied during plasma surfacing welding of Fe314 self-fluxing alloy powder additive manufacturing process. The changes of microstructures, properties, stress and deformation of the formed parts subjecting to vibration were analyzed and compared by means of blind hole method, scanning electron microscope, tension test and so on. The results show that it is detrimental to the formation of thin-walled parts and fine structures after the vibration is applied, however, the residual deformation and residual stress of the formed sample are improved to some extent. When the vibration acceleration is 4 m/s(2) and 6 m/s(2), the residual stress and deformation can be obviously reduced. After vibration, the microstructure of the formed samples is significantly refined and the tensile properties are improved. When the vibration acceleration is 4 m/s(2), the dendrites are significantly refined and the comprehensive mechanical properties are distinctly improved.

Adsorption of Cr6+ and Pb2+ on Soy Sauce Residue Biochar from Aqueous Solution

期刊: BIORESOURCES, 2019; 14 (2)

Biochar produced by the pyrolysis of biomass can be used to counter water pollution from heavy metals. The purpose of this work was to develop a biosorbent based on soy sauce residue (SSR) for the removal of Cr-6(+) and Pb2+. The SSR biochar (SBC) from oxygen-limited pyrolysis under the temperatures of 300 to 700 degrees C were obtained, and their adsorption capability was evaluated. After determining the optimum pyrolysis temperature, the effects of initial pH values, contact times, and initial metal concentrations on the Cr6+ and Pb2+ adsorption by SBC prepared at 600 degrees C (SBC600) were investigated. With the increase of pyrolysis temperature, the physical and chemical properties of SBC developed in a direction favorable to heavy metal adsorption. The SBC600 reached the adsorption equilibrium at the time of 2 (Cr6+) and 24 h (Pb2+), and the maximum adsorption amounts of Cr6+ and Pb2+ were 25.80 and 135.3 mg/g, respectively. The adsorption kinetics followed the pseudosecond-order kinetic equation, and the adsorption isotherms was best described by the Langmuir isotherms. The SBC was an adsorbent with certain potential for heavy metals removal in wastewater.

IF:1.4

A novel pumpkin seeds protein-pea starch edible film: mechanical, moisture distribution, surface hydrophobicity, UV-barrier properties and potential application

期刊: MATERIALS RESEARCH EXPRESS, 2019; 6 (12)

The pumpkin seeds protein (PSP) films have good gas barrier properties and elongation at break, but their inferior tensile strength and high moisture adsorption needed to be overcome. There are few reports about modification of PSP films so far. This study was to investigate the effects of different ratios (0:5, 1:4, 1.5:3.5, 2:3, 2.5:2.5 and 5:0) of pea starch (PS)/pumpkin seeds protein (PSP) on the morphology, mechanical properties, water vapor permeability (WVP), optical properties, hydrophobicity, and oil resistance of blend films. According to the results, the scanning electron micrographs of surface and cross-sections indicated the good biocompatibility between PS and PSP. The tensile strength was enhanced from 5.02 MPa to 16.41 MPa with the incorporation of PS at 40% level, but the elongation at break was decreased meanwhile. The addition of PS enhanced the hydrophobicity and reduced the swelling degree of films. And then, the composite films incorporated with PS were more transparent at visible region. The oil soaking had little effect on the mechanical properties of composite films with low starch content. The addition of starch led to the closer interaction between water molecules and macromolecules in film-forming matrix. In addition, the PS/PSP composite films showed inferior barrier properties of water vapor and ultraviolet light compared with pure PSP films. Based on the above various factors, the composite film composed of PS and PSP in a suitable proportion has the potential to package oily foods.

IF:1.45

A direct absorption solar collector based on a water-ethylene glycol based nanofluid with anti-freeze property and excellent dispersion stability

期刊: RENEWABLE ENERGY, 2019; 133 ()

Herein a direct absorption solar collector (DASC) with the reduced graphene oxide (RGO)/water-ethylene glycol (EG) nanofluid as the working fluid was firstly explored. The RGO/water-EG nanofluid was prepared from a GO/water-EG nanofluid at a loading of 0.06% via the UV irradiation for 240 s. It is shown that the zeta potential of the RGO/water-EG nanofluid increases with temperature, suggesting its excellent dispersion stability at elevated temperatures. The base liquid consisting EG and water endows the nanofluid with anti-freeze property, making its DASC can be applied in cold weather. The RGO/water-EG nanofluid exhibited better optical absorption property and thermal conductivity than the previously reported RGO/water nanofluid. After being exposed under a solar intensity of 1000 W/m(2) for 6000 s, the temperature increase of RGO/water-EG nanofluid increases by 76.9% and the receiver efficiency increases by 70%, as compared to the base fluid. These good characteristics make RGO/water-EG nanofluid promising working fluid for DASCs. Consequently, a numerical simulation was employed to study the DASC based on the nanofluid with the liquid heights varying from 2 to 10 cm. It is revealed that the DASC based on the RGO/water-EG nanofluid exhibits good photo-thermal conversion performance and receiver efficiency, thus showing great potential in practical applications. (c) 2018 Elsevier Ltd. All rights reserved.

IF:5.44

Stabilization of Fluorescent [Ag-m](n+) Quantum Clusters in Multiphase Inorganic Glass-Ceramics for White LEDs

期刊: ACS APPLIED NANO MATERIALS, 2019; 2 (5)

Silver quantum clusters ([Ag-m](n+) QCs) are a type of efficient broadband fluorescence centers with m and n related quantum size effects but usually lack chemical and thermal stability. To solve such a problem and exploit [Ag-m](n+) QCs potential applications in white LED lighting, [Ag-m](n+) QCs and rare earth ions (RE3+) were designed to be selectively enriched into B2O3-rich spinodal nanophase separation and SrF2 nanocrystals in fluoroborosilicate multiphase glass-ceramics. In this work, Ag/RE3+-codoped glasses and glass-ceramics with a designed composition were prepared through a melt-quenching method and subsequent heat treatment. The B2O3-rich spinodal nanophase separation and SrF2 nanocrystals were stepwise formed in these glass-ceramics. Taking Ag/E-r3+-codoped glass-ceramics for an example, the special microstructures were clearly revealed by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectroscopy (EDX) mappings. By the strategies of controlling [Agl solubility and charge compensating to [AlO4](-), [BO4](-), and [ZnO4](2-) tetrahedra, a large quantity of [Ag-m](n+) QCs were stabilized in the glass networks with regulated m and n. By the strategies of RE3+/Al-3 and Ag+/Na- competitive distribution, the solubility of Ag+ in B2O3-rich glassy phases was effectively increased, and [Ag-m](n+) QCs were eventually stabilized to withstand the postcrystallization procedures at high temperatures up to 650 degrees C. By the multiphase strategy, Ag and RE3+ were selectively partitioned into the B2O3-rich nanosize glassy phases and SrF2 nanocrystals, respectively. Thus, energy transfers (ETs) between [Ag-m](n+) and RE3+ can be well-suppressed to enhance the photoluminescence quantum yields (PL QYs) of the multiphase glass-ceramics. Those engaged [Ag-m](n+) with largely improved white light-emitting diode (WLED) performances, e.g., QY and color rendering index (CRI), in the glass-ceramics. This suggests that Ag/RE3+-codoped glass-ceramics can be ideal candidate phosphors for high-power WLED lighting devices.

Complex network analysis of bilateral international investment under de-globalization: Structural properties and evolution

期刊: PLOS ONE, 2019; 14 (4)

As many countries are now seeking to protect their own markets rather than indulge in global trade, this paper examines whether this type of de-globalization behavior has been having any effect on international investment relationships through a systematic analysis of international investment network (IIN) in 127 economies from 2005 to 2016. Unlike previous studies that only analyzed portfolio investment data, the bilateral international investment data were estimated using a matrix-based iteration approach, and the IIN established using complex network theory. Using bilateral international investment data made the results more reliable and somewhat closer to reality. To analyze the structural properties and evolution of the IIN, complex network indicators including a new one named node similarity were developed. The node similarity is defined as the proportion of common relationships of the current economy between two successive years which is useful to reveal the dynamics of the IIN. This paper finds that there are heterogenous and hierarchal properties in the IIN, several economies had a wide range of international investment partners, while most others had only a small range of investment partners and were more likely to form tight groups within the network. The economies in the IIN were tending towards smaller but closer communities, a new trend of regional financial cooperation was developing. The IIN is divided into more communities over time while the top active and central economies often locate in different communities. These findings imply that the structure of the IIN is changing geographically during the de-globalization rather than independent with regions. The regional cooperation has made positive effect on the international investment. The governments should ensure that they continue to support liberal financial policies and to promote better regional financial cooperation.

IF:2.78

A note on "Lattice soliton equation hierarchy and associated properties"

期刊: CHINESE PHYSICS B, 2019; 28 (1)

We demonstrate that the new hierarchy of integrable lattice equations in Chin. Phys. B 21 090202 (2012) can be changed into the integrable lattice hierarchy in Chin. Phys. B 13 1009 (2004) by using a very simple transformation.

IF:1.47

Nonclassical properties of induced states from single-mode squeezed vacuum state related with Hermite excited elementary superposition operation

期刊: EUROPEAN PHYSICAL JOURNAL PLUS, 2019; 134 (4)

.Based on single-mode squeezed vacuum state (SVS) and Hermite-excited elementary superposition operator Hm(xa dagger+ya), we induce two new quantum states, i.e., Hermite-excited squeezed vacuum state (HSVS) and Hermite-excite-orthogonalized squeezed vacuum state (HOSVS). HSVS is obtained by applying the operator on SVS and HOSVS is obtained by applying the orthogonalizer on SVS, where HSVS is just HOSVS for odd m. We study and compare mathematical and nonclassical properties for SVS, HSVS and HOSVS, including photon number distribution, Mandel's Q parameter, quadrature squeezing, and Wigner function. Numerical results show that i) HSVS and HOSVS have only even (odd) photon components for even (odd) m; ii) HSVS and HOSVS can exhibit sub-Poissonian statistics in low-squeezing parameter regime and squeezing effect in large-squeezing parameter regime; iii) moreover, squeezing is always incompatible with sub-Poissonianity; iv) Wigner functions for HSVS and HOSVS have negative values in phase space.

IF:2.61

Production of exotic neutron-deficient isotopes near N, Z=50 in multinucleon transfer reactions

期刊: CHINESE PHYSICS C, 2019; 43 (6)

The multinucleon transfer reaction in the collisions of Ca-40+ Sn-124 at E-c.m. = 128.5 MeV is investigated using the improved quantum molecular dynamics model. The measured angular distributions and isotopic distributions of the products are reproduced reasonably well by the calculations. The multinucleon transfer reactions of Ca-40 + Sn-112, Ni-58 +Sn- 112, Cd-106 + Sn-112, and Ca-48 + Sn-112 are also studied. This demonstrates that the combinations of neut- ron-deficient projectile and target are advantageous for the production of exotic neutron-deficient nuclei near N, Z = 50. The charged particles' emission plays an important role at small impact parameters in the de-excitation processes of the system. The production cross sections of the exotic neutron-deficient nuclei in multinucleon transfer reactions are much larger than those measured in the fragmentation and fusion-evaporation reactions. Several new neutron-deficient nuclei can be produced in the Cd-106 + Sn-112 reaction. The corresponding production cross sections for the new neutron-deficient nuclei, (101,) Sb-112, Te-103, and( 106, 107)I, are 2.0 nb, 4.1 nb, 6.5 nb, 0.4 mu b and 1.0 mu b, respectively.

IF:5.86

The grain refinement of 1070 alloy by different Al-Ti-B mater alloys and its influence on the electrical conductivity

期刊: RESULTS IN PHYSICS, 2019; 14 ()

The excellent grain refinement effectiveness and good electrical conductivity is difficult to be simultaneously obtained due to the influence of both the grain boundary and excessive Ti in the usually used refiners, such as Al-5Ti-1B master alloy. In order to solve this problem, in this work, Al-Ti-B mater alloys with less or without excessive Ti but with high refinement potency TiB2 have been tried to prepare, and the grain refinement effectiveness of them and its influence on the electrical conductivity of the refined Al have been investigated. It is found that the grain refinement effectiveness of the Al-Ti-B master alloys prepared using the Al-5Ti-1B and Al-B master alloys as the starting materials at 720 degrees C is much better than those prepared using the Al-10Ti and Al-B master alloys, which is because that the high refinement potency TiB2 with TiAl3 2DC in the Al-5Ti-B can be kept in the prepared master alloys. As a result, using the prepared Al-Ti-B master alloys as the refiners, both the good grain refinement effectiveness and improved electrical conductivity of Al can be realized.

IF:3.04

Dynamical evolution of photon-added thermal state in thermal reservoir

期刊: CHINESE PHYSICS B, 2019; 28 (11)

The dynamical behavior of a photon-added thermal state (PATS) in a thermal reservoir is investigated by virtue of Wigner function (WF) and Wigner logarithmic negativity (WLN), where this propagation model is abstracted as an input?output problem in a thermal-loss channel. The density operator of the output optical field at arbitrary time can be expressed in the integration form of the characteristics function of the input optical field. The exact analytical expression of WF is given, which is closely related to the Laguerre polynomial and is dependent on the evolution time and other interaction parameters (related with the initial field and the reservoir). Based on the WLN, we observe the dynamical evolution of the PATS in the thermal reservoir. It is shown that the thermal noise will make the PATS lose the non-Gaussianity.

IF:1.47

A new type of adiabatic invariants for disturbed non-conservative nonholonomic system

期刊: CHINESE PHYSICS B, 2019; 28 (12)

According to the Herglotz variational principle and differential variational principle of Herglotz type, we study the adiabatic invariants for a non-conservative nonholonomic system. Firstly, the differential equations of motion of the non-conservative nonholonomic system based upon the generalized variational principle of Herglotz type are given, and the exact invariant for the non-conservative nonholonomic system is introduced. Secondly, a new type of adiabatic invariant for the system under the action of a small perturbation is obtained. Thirdly, the inverse theorem of the adiabatic invariant is given. Finally, an example is given.

IF:1.47

Decomposing the Toda hierarchy by an implicit symmetry constraint

期刊: MODERN PHYSICS LETTERS B, 2019; 33 (3)

An implicit symmetry constraint of the famous Toda lattice hierarchy is presented. Using this symmetry constraint, every lattice equation in the Toda hierarchy is decomposed by an integrable symplectic map and a completely integrable finite-dimensional Hamiltonian system.

IF:0.93

A hydroxyquinoline-appended ruthenium(II)-polypyridyl complex that induces and stabilizes G-quadruplex DNA

期刊: JOURNAL OF COORDINATION CHEMISTRY, 2019; 72 (2)

A polypyridyl ruthenium(II) complex with hydroxyquinoline-derived ligand has been synthesized and characterized. The ability to act as telomeric quadruplex inducer and stabilizer, and quadruplex-binding properties of the complex have been evaluated by absorption and emission analyses, fluorescent intercalator displacement (FID) titrations, circular dichroism (CD) spectroscopy, polymerase chain reaction (PCR) stop assay, color reaction studies, fluorescence resonance energy transfer (FRET) melting assay, Job plot, and molecular modeling. Observations revealed that the complex could well induce and stabilize the formation of antiparallel G-quadruplex of telomeric DNA in the presence or absence of metal cations, and showed superior G-quadruplex selectivity over duplex DNA with remarkable Delta T-m value of 18.0 degrees C even at 50-fold excessive supplies of calf thymus (ct) DNA. The complex exhibited high interaction affinity of 2.56 x 10(6) M-1 with G-quadruplex DNA and evident luminescence enhancements of 3.1 and 4.2 times for quadruplex binding in Na+ and K+ buffer, respectively. In addition, the 1:1 [quadruplex]/[complex] binding mode ratio was determined. The results suggest that the complex can be developed as potential anticancer reagent through binding and stabilization of G-quadruplex DNA. [GRAPHICS] .

IF:1.68

Structural Changes of Mercaptohexanol Self-Assembled Monolayers on Gold and Their Influence on Impedimetric Aptamer Sensors

期刊: ANALYTICAL CHEMISTRY, 2019; 91 (22)

Despite a large number of publications describing biosensors based on electrochemical impedance spectroscopy (EIS), little attention has been paid to the stability and reproducibility issues of the sensor interfaces. In this work, the stability and reproducibility of faradaic EIS analyses on the aptamer/mercaptohexanol (MCH) self-assembled monolayer (SAM)-functionalized gold surfaces in ferri- and ferrocyanide solution were systematically evaluated prior to and after the aptamer-probe DNA hybridization. It is shown that the EIS data exhibited significant drift, and this significantly affected the reproducibility of the EIS signal of the hybridization. As a result, no significant difference between the charge transfer resistance (R-CT) changes induced by the aptamer-target DNA hybridization and that caused by the drift could be identified. A conditioning of the electrode in the measurement solution for more than 12 h was required to reach a stable R-CT baseline prior to the aptamer-probe DNA hybridization. The monitored drift in R-CT and double layer capacitance during the conditioning suggests that the MCH SAM on the gold surface reorganized to a thinner but more closely packed layer. We also observed that the hot binding buffer used in the following aptamer-probe DNA hybridization process could induce additional MCH and aptamer reorganization, and thus further drift in R-CT. As a result, the R(CT )change caused by the aptamer-probe DNA hybridization was less than that caused by the hot binding buffer (blank control experiment). Therefore, it is suggested that the use of high temperature in the EIS measurement should be carefully evaluated or avoided. This work provides practical guidelines for the EIS measurements. Moreover, because SAM-functionalized gold electrodes are widely used in biosensors, for example, DNA sensors, an improved understanding of the origin of the observed drift is very important for the development of well-functioning and reproducible biosensors.

IF:6.35

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