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The carbonation resistance of high performance concrete is closely related to the service life of concrete structure, and is an important parameter to reflect its durability. The carbonation resistance of concrete is influenced on selection of curing conditions greatly. In the paper, based on the common curing conditions, the carbonation tests of high performance concrete under different curing methods and curing time were carried out, and the influence mechanism of curing conditions on the carbonation resistance of materials was qualitatively analyzed. The exponential function expression of curing time and carbonation depth was fitted when curing by wet straws. The results show that: in terms of carbonation resistance, the order is wet straw curtain curing, plastic film curing and curing agent curing, and should be cured in advance. The carbonation depth is effectively reduced by short-term curing (3d) and medium-term curing (7d), but the reduction rate slows down, and 7d curing is suggested. The fitted prediction model is calculated the carbonation depth of concrete materials, and the test results are provided data for the selection of curing conditions and time of engineering.

We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic field and to the magnitude of the applied current. Large anomalous variations are also observed in the symmetric part of the transverse resistance Rxy . We suggest that the surface current loops on superconducting grains at the edges of the superconducting thin films may be responsible for the Hall sign reversal and the accompanying anomalous effects in the symmetric part of Rxy .

Measurement of a reaction between deuterium (hydrogen) gas and materials using a calorimeter which is calibrated by nitrogen will show erroneous excess heat power production due to the structure of the reaction chamber and the difference of thermal conductivity of the gases used in the calibration and triggering experiments, which leads to the energy generated in the chamber of the calorimeter has not been totally measured. The error is not obvious at low applied power, and it increases significantly with the increase of applied power. This insidious error is discussed by using a stable heat-flow (Seebeck) calorimeter and procedures to reduce error are put forward. And the authenticity of Rossi’s patent is questioned.

In the field of low energy nuclear reaction, isothermal calorimetry is often used to calculate the excess heat power released in the system. Due to the structure of the reaction chamber and the differences of the thermal conductivities of the gases used in the calibration and triggering experiments, the chamber will have different temperature gradient or distribution which leads to errors when calculating the excess heat power using isothermal calorimetry. Different gas pressure also has an influence on the heat transfer.

Gallium arsenide (GaAs), a typical covalent semiconductor, is widely used in the electronic industry, owing to its superior electron transport properties. However, its brittle nature is a drawback that has so far significantly limited its application. An exploration of the structural deformation modes of GaAs under large strain at the atomic level, and the formulation of strategies to enhance its mechanical properties is highly desirable. The stress-strain relations and deformation modes of single-crystal and nanotwinned GaAs under various loading conditions are systematically investigated, using first-principles calculations. Our results show that the ideal strengths of nanotwinned GaAs are 14% and 15% higher than that of single-crystal GaAs under pure and indentation shear strains, respectively, without producing a significantly negative effect in terms of its electronic performance. The enhancement in strength stems from the rearrangement of directional covalent bonds at the twin boundary. Our results offer a fundamental understanding of the mechanical properties of single crystal GaAs, and provide insights into the strengthening mechanism of nanotwinned GaAs, which could prove highly beneficial in terms of developing reliable electronic devices.

Comprehensive study of urban underground space status, efficiently configuring urban underground space resources to serve urban construction. This article selects the integrated analytical system of two levels of engineering geology, hydrological geology, environmental geology and human activities, and draws the weight value of the factor factor weight and the corresponding layer superimposed by one item by item. Sexual distribution. Choosing Chongqing Wulong is a research area, constructs 4 first-level indicators and 11 secondary indicators comprehensive evaluation system, and the factor weight value and adaptation map shows that Wulong Research Area should focus on environmental geological conditions, urban underground space division 3 A total of 12 pieces of zones, and the evaluation results can provide reference for the construction of Wulong city.

In the two states of oil-gas and water-gas, the wave velocity and attenuation coefficient are numerically simulated by double-scale model. The P-wave velocity and attenuation coefficient curves show double-step and double-peak, respectively. With the increase of gas saturation, the velocity step of mesoscopic scale gradually decreases and disappears. The attenuation peak decreases and the characteristic frequency shifts to high frequency until it coincides with the characteristic frequency of the micro-scale. The superposition of the attenuation peak makes the total attenuation peak increase. And there is a great difference in fluid properties when oil, gas and water are mixed in the reservoir, so the double-scale model can better predict the fluid saturation in the reservoir and better monitor the fluid.

Herein, the desorption effect of supercritical CO2 (scCO2) was utilized to obtain sub-5 nm Ag nanoparticles (NPs) with a high Ag loading in SBA-15. The size of the Ag NPs decreased from 3.54 ± 0.79 nm (Ag loading of 25.3 wt.% wt.%) to 2.38 ± 0.68 (Ag loading of 10.5 wt%) nm by changing the depressurization curve from 0.1 MPa min-1 (20-14 MPa) to 3 MPa min-1 (20-12 MPa). Meanwhile, the intensity of the crystalline Ag characteristic peaks was obviously higher than the latter sample from the x-ray diffraction (XRD) patterns. However, compared with the adsorption kinetics of the two precursors of AgNO3 and Cu(NO3)2 on SBA-15, under the same deposition and depressurization conditions, when the two depositional systems used water as a co-solvent, the time taken to reach the adsorption equilibrium of Ag+ on the supports was longer than the time taken by Cu2+, which existed in the water as [Cu(H2O)4]2+. The surface of SBA-15 was hydrophilic, and then the interaction of Ag+ and the surface was weaker compared with Cu2+, making Ag+ highly dispersed on the surface under the scCO2 desorption effect. After calcination, the size of the Ag NPs decreased, but the morphology of CuO was mainly characterized by nanorods (NRs). Moreover, by comparing the experiments of wetness impregnation, the dispersion ability of the bulk scCO2 of the reactor was inefficient for Ag+ adsorbed on the channels in the depressurization process.

The safety inspection network of hydraulic engineering metallic structures and equipments was developed based on the Cloud platform technology. The experimental inspections of metallic structures in terms of the coating thickness, metal substrate thickness, welding defect and the structure stress were conducted in the under-constructed hydraulic projects in Shenzhen City. The results showed that the manual inspection data of the coating and metal thickness and the non-destructive testing scene photos and results can be transmitted to the cloud platform in real time through semi-automatic mode. Differently, the dynamic variation value of structure stress is automatically collected by the intelligent acquisition module and then wirelessly transmitted to the Cloud platform. By granting access rights to relevant personnel of quality and safety supervision department, they can ensure real-time supervision of safety inspection results and receive alarm information.

Thermal expansion coefficient is a regular coefficient to describe the variation of geometric characteristics of matter under the action of thermal expansion and cold shrinkage effect, and it is an important index to measure the thermal stability of materials. A device for measuring the thermal expansion coefficient of solid materials by Yang’s double slit interferometric method with variable double slit spacing is mainly composed of laser, sliding Young double slit structure, temperature measuring and controlling instrument, shading tube, receiving device and solid material to be measured. The solid material is heated by ring heater, the temperature of solid material is displayed and controlled by temperature measuring and controlling instrument, and the change of stripe spacing is recorded by linear CCD image sensor. Compared with the traditional optical leverage method, this measuring device and method can significantly improve the accuracy of the measurement results and reduce the uncertainty of the measurement results.

Here, we present a novel method to control the size of CuO nanoparticles (NPs) and Cu loading in SBA-15 via fast desorption of supercritical CO2 (scCO2). After calcination, the average size of the CuO NPs (6.47 ± 2.89∼2.18 ± 0.97 nm) decreased with the increase of the depressurization rate (20-14 MPa, 50 °C) from transmission electron microscopy, and the x-ray diffraction results also indicated the decrement of the average particle size (8.6∼4.3 nm by a Scherrer equation). Two reduction peaks situated at 195 °C and 220 °C were found from the temperature-programmed reductions with H2 profiles, and the intensity of the low-temperature peak increased with increasing the rate for a profile. The hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG) was selected to evaluate the catalytic activity of the as-prepared sample. The reaction was conducted at p = 3.0 MPa, T = 200 °C, H2/DMO = 120, the weight hourly space velocity = 1.2 h-1, and the EG selectivity remained at about 90% for over 100 h. The fast desorption of scCO2 caused mechanical perturbations and crystallization of the adsorbed salt ions on the supports, decreasing the particle size and increasing Cu loading (8∼12 wt%).

There are many classification methods for temporary plugging volume fracturing. According to different temporary plugging positions and temporary plugging targets, temporary plugging volume fracturing technology can be divided into temporary plugging in fractures and temporary plugging between fractures. According to the number of temporary plugging, it can be divided into one temporary plugging and multi-level temporary plugging. According to the action mode of temporary plugging, it can be divided into physical temporary plugging and chemical temporary plugging. According to the type of temporary plugging agent, it can be divided into plugging balls (plastic balls, rubber balls, nylon balls, wax balls) temporary plugging, fiber temporary plugging, large particle size proppant temporary plugging, etc. In Changqing, Daqing and Xinjiang oilfields in China, temporary plugging agents have been reported to be used for in-fracture diversion fracturing to improve reservoir productivity, and certain effects have been achieved. Compared with conventional staged fracturing, the temporary plugging of the seam to fracturing technology has the following advantages: conventional staged fracturing is difficult to implement, the temporary plugging of the seam to fracturing technology can be used to realize effective layering (segment) reconstruction, general fracturing reconstruction is insufficient, and temporary plugging of the seam to fracturing can be used to improve thereconstruction effect.

Jilin Province is an important petrochemical, electronic research and development and agricultural product breeding base in China. After more than 30 years of reform and opening up, its economic construction has made great progress and has shown rapid development momentum. E-commerce and economic growth have driven the development of the logistics industry and promoted the growth and development of the aviation logistics industry. In the low-carbon and environmentally-friendly environment, the aviation logistics industry has been constrained by the macro-system, the impact of other logistics channels, the shortage of logistics talents, and the restrictions on carbon emissions, making the development of aviation logistics industry in Jilin Province difficult. Based on this background, the paper uses SWOT analysis method to systematically analyse the advantages and disadvantages of Jilin Airlines logistics industry and development opportunities and threats, and proposes solutions to how to develop aviation logistics under the current low-carbon environmental protection policy.

The competition of isovector and isoscalar pairing in A=18 and 20 even-even N≈Z nuclei is analyzed in the framework of the mean-field plus the dynamic quadurpole-quadurpole, pairing and particle-hole interactions, whose Hamiltonian is diagonalized in the basis in the L = 0 configuration subspace. Besides the pairing interaction, it is observed that the quadurpole-quadurpole and particle-hole interactions also play a significant role in determining the relative positions of low-lying excited 0+ and 1+ levels and their energy gaps, which can result in the ground state first-order quantum phase transition from J = 0 to J = 1. The strengths of the isovector and isoscalar pairing interactions in these even-even nuclei are estimated with respect to the energy gap and the total contribution to the binding energy. Most importantly, it is shown that although the mechanism of the particle-hole contribution to the binding energy is different, it is indirectly related to the Wigner term in the binding energy.

It is essential to synthesize low-cost, earth-abundant bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) for water electrolysis. Herein, we present a one-step sulfurization method to fabricate Ni3S2 nanowires directly grown on Ni foam (Ni3S2 NWs/Ni) as such an electrocatalyst. This synthetic strategy has several advantages including facile preparation, low cost and can even be expanded to large-scale preparation for practical applications. The as-synthesized Ni3S2 NWs/Ni exhibits a low overpotential of 81 and 317 mV to render a current density of 10 mA cm-2 for the HER and OER, respectively, in 1.0 mol l-1 KOH solution. The Ni3S2 NWs/Ni was integrated to be the cathode and the anode in the alkaline electrolyzer for overall water splitting with a current density of 10 mA cm-2 afforded at a cell voltage of 1.63 V. More importantly, this electrolyzer maintained its electrocatalytic activity even after continual water splitting for 30 h. Owing to its simple synthesis process, the earth-abundant electrocatalyst and high performance, this versatile Ni3S2 NWs/Ni electrode will become a promising electrocatalyst for water splitting.

Many efforts have been devoted to the exploration of non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) in recent years. Here, we have developed a 3D-MoO2 microsphere supported MoSe2 for HER, via a facile hydrothermal approach followed by selenylation treatment. Loosely stacked MoSe2 layers are formed on the conductive MoO2 surface, and act as active sites for HER. Meanwhile, the metallic inner MoO2 facilitates electron transport for proton reduction. In addition, the MoSe2 could protect the inner MoO2 from the acidic electrolyte in the HER precess. Significantly, the as-synthesized MoO2/MoSe2 exhibits excellent catalytic activity for HER, characterised by a low onset potential of −101 mV vs reversible hydrogen electrode, a small overpotential of 167 mV at a current density of 10 mA cm−2, along with Tafel slope values of 68 mV dec−1, as well as outstanding stability in 0.5 mol L−1 H2SO4.

The optical properties of 0.65Pb(Mg1/3Nb2/3)O3?0.35PbTiO3 (PMN?0.35PT) single crystals were investigated by means of the optical transmittance spectrum. The refractive indices were measured in the visible region, and the dispersion behaviours of ordinary and extraordinary lights were well described in terms of the Wemple?Didomenico single oscillator dispersion model. The optical band gap values were obtained from the Tauc model. For (1 ? x) Pb(Mg1/3Nb2/3)O3 ? xPbTiO3 single crystals, as the PbTiO3 content increases, the refractive index increases, while the optical band gap energy decreases.

The Ag doped ZnO films were prepared on sapphire substrates using simple thermal evaporation method. The effect of annealing treatment was investigated in detail. The results shows that the annealed Ag doped ZnO film has a prefer orientation along c-axis. The E2 (high) mode in Raman spectra has a little blue shift which caused by crystal defects oxygen vacancies, meanwhile the compressive stress was exist in the film. After annealed, the intense of E2 modes have great improvement which means the quality of the film was enhanced, meanwhile, the compressive stress released to some extent.

We report the systematic comparison of the optical emission intensity of the vibrational band of the Swan system with the absolute concentration in and microwave plasmas used in the deposition of nanocrystalline diamond. The absolute concentration is obtained using white-light absorption spectroscopy. Emission intensity correlates linearly with density for variations of several plasma parameters and across two decades of species concentration. Although optical emission intensity generally is not an accurate quantitative diagnostic for gas phase species concentrations, these results confirm the reliability of the (0,0) Swan band for relative determination of density with high sensitivity under conditions used for hydrogen-deficient plasma-enhanced chemical vapour deposition of diamond.

The temperature dependence of the coupling constants kμν and piezoelectric constants dμν, gμν of transverse and shear mode 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 (PMN–29%PT) single crystals with optimal orientation from room temperature to 115 °C were reported. From 20 °C to approximately 80 °C, k31 increases slightly from 91.0% to 93.5%, while d31 increases from 1900.0 to 4500.0 pC N−1. When the temperature exceeds 80 °C, both k31 and d31 begin to drop. Similarly, the coupling factor k15 increases from 95% to 97%, while the piezoelectric constant d15 increases from 4769.4 to 14293.2 pC N−1when the temperature rises from room temperature to 93 °C. When the temperature goes beyond 93 °C, the shear-mode piezoelectric properties start to decay. We also study the temperature dependence of the elastic compliances and , both of which show strong dependence of the temperature. The service temperature for PMN–29%PT is determined to be lower than 80 °C for transverse vibration and lower than 93 °C for shear-mode samples. These would effectively guide the correlative device designs and practical applications.

The complete set of elastic, dielectric and piezoelectric properties of [0 0 1]-poled domain-engineered 0.72Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 (PMN–0.28PT) single crystals was determined. Their ultrahigh piezoelectric constant d33 of 2365 pC N−1 and superior electromechanical coupling coefficients k33, k31 and kt of 93.9%, 76.0% and 63.1%, respectively, are obtained. The temperature dependence of the dielectric properties of [0 0 1]-poled PMN–xPT (x = 0.28, 0.30, 0.32) single crystals was compared. The results showed that the PMN–0.28PT single crystal has an obviously higher phase transition temperature Trt (ferroelectric rhombohedral phase to tetragonal phase transition) than that of other compositions with comparable piezoelectric properties. All these would be highly favourable for practical piezoelectric applications.

A large single crystal of 0.95Na0.5Bi0.5TiO3?0.05BaTiO3 (0.95NBT?0.05BT) with dimensions of 35?mm diameter ? 10?mm length was grown by the top-seeded-solution growth method (TSSG). X-ray powder diffraction results indicate that the as-grown 0.95NBT?0.05BT crystal is of a perovskite structure and belongs to the rhombohedral system. The dielectric, ferroelectric and piezoelectric properties were investigated in detail. The room temperature dielectric constants for unpoled 0?0?1, 1?1?0 and 1?1?1 oriented crystal samples are 1450, 1650 and 1750 at 1?kHz and decrease to 1050, 800 and 480 after poling. The remanent polarizations Pr of 0?0?1, 1?1?0 and 1?1?1 oriented crystal samples are 16.44??C?cm?2, 23.69??C?cm?2 and 27.63??C?cm?2 with the coercive fields Ec of 32.72?kV?cm?1, 31.20?kV?cm?1 and 28.15?kV?cm?1, respectively. Interestingly, the piezoelectric constant d33 of the 0.95NBT?0.05BT crystal shows apparent anisotropy along its pseudocubic 0?0?1, 1?1?0 and 1?1?1 directions. The 0?0?1 poled 0.95NBT?0.05BT crystals show excellent piezoelectric properties with d33 = 280?pC?N?1. However, the d33 values of the 1?1?1 oriented 0.95NBT?0.05BT crystal are only 90?pC?N?1. The origin of apparent anisotropy in piezoelectric properties has been discussed in detail.