Mid-IR Multiwavelength Difference Frequency Generation Based on Fiber Lasers

A mid-IR multiwavelength difference frequency generation (DFG) laser source with fiber laser fundamental lights is demonstrated by using the dispersion property of PPLN to broaden the quasi-phase-matching (QPM) acceptance bandwidth (BW). Our results show that the QPM BW for the pump YDFL is much larger than that for the signal EDFL. Using a multiwavelength YDFL and a single-wavelength EDFL as the pump and the signal lights, the DFG laser source can simultaneously emit 14 mid-IR wavelengths with the spacing of 14nm at a fixed PPLN temperature. Moreover, mid-IR multiwavelength lasing lines can be synchronously tuned between 3.28 and 3.47μm

Earthquake response of large-span reinforced concrete structures with haunch braces under vertical ground motions

A new type of reinforced concrete (RC) frame system with diagonal haunch braces is introduced in a large-span sports education building. In this paper, the nonlinear dynamic responses of the large-span RC frame structures with diagonal haunch braces (RCFB) are studied under vertical near-fault pulse-like and non-pulse-like ground motions. Ten ground motions of the Chichi earthquake event are selected and divided into two groups. The large-span plane RCFB structure is simplified from a practical engineering structure and used to perform a dynamic time-history analysis. The vertical mid-beam displacement and the axial pressure at the base of the bottom column of the structure are compared under vertical pulse-like and vertical non-pulse-like ground motions, and the effects of the structural system parameters on the vertical mid-beam displacement are analyzed. This study shows that the vertical earthquake response of a large-span RCFB structure is significant, especially under pulse-like ground motions, and that the structural system parameters and the impulsive effect of ground motion exhibit a distinct coupled effect on the vertical response. Optimizing the location of haunch braces is very critical in RCFB structural design

A constitutive model for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures

Quasi-static and dynamic tension tests were conducted to study the mechanical properties of particulate-reinforced titanium matrix composites at strain rates ranging from 0.0001/s to 1000/s and at temperatures ranging from 20 °C to 650 °C Based on the experimental results, a constitutive model, which considers the effects of strain rate and temperature on hot deformation behavior, was proposed for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures by using Zener-Hollomon equations including Arrhenius terms. All the material constants used in the model were identified by fitting Zener-Hollomon equations against the experimental results. By comparison of theoretical predictions presented by the model with experimental results, a good agreement was achieved, which indicates that this constitutive model can give an accurate and precise estimate for high temperature flow stress for the studied titanium matrix composites and can be used for numerical simulations of hot deformation behavior of the composites

Enhanced superconductivity at the interface of W/Sr2_{2}RuO4_{4} point contact

Differential resistance measurements are conducted for point contacts (PCs) between tungsten tip approaching along the $c$ axis direction and the $ab$ plane of Sr$_{2}$RuO$_{4}$ single crystal. Three key features are found. Firstly, within 0.2 mV there is a dome like conductance enhancement due to Andreev reflection at the normal-superconducting interface. By pushing the W tip further, the conductance enhancement increases from 3\% to more than 20\%, much larger than that was previously reported, probably due to the pressure exerted by the tip. Secondly, there are also superconducting like features at bias higher than 0.2 mV which persists up to 6.2 K, resembling the enhanced superconductivity under uniaxial pressure for bulk Sr$_{2}$RuO$_{4}$ crystals but more pronounced here. Third, the logarithmic background can be fitted with the Altshuler-Aronov theory of tunneling into quasi two dimensional electron system, consistent with the highly anisotropic electronic system in Sr$_{2}$RuO$_{4}$.Comment: prb style, 9 pages, 8 fig

The role of taxation in tobacco control and its potential economic impact in China

ObjectivesTo identify key economic issues involved in raising the tobacco tax and to recommend possible options for tobacco tax reform in China.MethodsEstimated price elasticities of the demand for cigarettes, prevalence data and epidemiology are used to estimate the impact of a tobacco tax increase on cigarette consumption, government tax revenue, lives saved, employment and revenue loss in the cigarette industry and tobacco farming.ResultsThe recent Chinese tax adjustment, if passed along to the retail price, would reduce the number of smokers by 630,000 saving 210,000 lives, at a price elasticity of -0.15. A tax increase of 1 RMB (or US$0.13) per pack of cigarettes would increase the Chinese government's tax revenue by 129 billion RMB (US 17.2 billion), decrease consumption by 3.0 billion packs of cigarettes, reduce the number of smokers by 3.42 million and save 1.14 million lives.ConclusionThe empirical economic analysis and tax simulation results clearly indicate that increasing the tobacco tax in China is the most cost-effective instrument for tobacco control

Experimental Research on Passive Control of Steel Frame Structure Using SMA Wires

Mechanical properties of shape memory alloy (SMA) wires were experimentally researched in this paper, and an energy dissipater made of SMA wire cable was designed and applied in a steel frame structure model by using superelasticity characteristics of SMAs to passively reduce dynamic responses of the steel frame structure under seismic load. For the characteristics of large relative displacements between the stories of the steel frame structure on both diagonal ends and the consideration of initial prestrain effects of the SMA cables, three kinds of the whole control, the part control, and no control of the shaking table tests and numerical simulations were carried, respectively. Through the results of the shaking table test and numerical simulation analysis, the dynamic responses such as the maximum displacement, velocity, and acceleration at the top layer of the steel frame structure applied with SMA cables are significantly decreased compared with the no control case. However, considering the premise of both effectiveness and efficiency, the part control effect is superior to the whole control. In many cases, it can meet the control requirement of reducing the maximum displacement and acceleration, while the superelasticity of SMAs can be sufficiently played, realizing the passive control purposes of the steel frame structure based on the energy dispassion through the application of the SMA cables. The proposed method has broad application prospects in the passive control field of building structures

Circ_0000284 facilitates the growth, metastasis and glycolysis of intrahepatic cholangiocarcinoma through miR-152-3p-mediated PDK1 expression

Background. Circular RNAs (circRNAs) are key molecules in the regulation of intrahepatic cholangiocarcinoma (ICC) progression. The purpose of this study was to analyze the function and underlying molecular mechanism of circ_0000284 in ICC. Methods. Quantitative real-time PCR was used to analyze the circ_0000284, microRNA (miR)-152-3p and pyruvate dehydrogenase kinase 1 (PDK1) expression. Cell proliferation, apoptosis, invasion and migration were executed by cell counting kit 8 assay, EdU assay, flow cytometry, transwell assay and wound healing assay, respectively. All protein expression levels were examined using western blot analysis. Cell glycolysis was analyzed by detecting glucose consumption, lactate production and ATP/ADP ratios. Target relationship was estimated by dual-luciferase reporter assay. The effect of circ_0000284 on ICC tumor growth in vivo was evaluated by constructing xenograft mice model. Results. We detected high expression of circ_0000284 in ICC tumor tissues and cells. Downregulated circ_0000284 inhibited ICC cell proliferation, invasion, migration, glycolysis, and accelerated apoptosis. MiR-152-3p was sponged by circ_0000284, and its inhibitor revoked the effect of circ_0000284 knockdown on ICC cell progression. PDK1 was a target of miR-152-3p, and its expression was suppressed by circ_0000284 knockdown. PDK1 overexpression reversed the inhibition effect of miR-152-3p on ICC cell growth, metastasis and glycolysis. In animal experiments, circ_0000284 downregulation also inhibited ICC tumor growth. Conclusion. Circ_0000284 promoted the growth, metastasis and glycolysis of ICC by miR-152-3p/PDK1 pathway, showing that circ_0000284 was a potential therapeutic target for ICC

Earthquake response of large-span reinforced concrete structures with haunch braces under vertical ground motions

A new type of reinforced concrete (RC) frame system with diagonal haunch braces is introduced in a large-span sports education building. In this paper, the nonlinear dynamic responses of the large-span RC frame structures with diagonal haunch braces (RCFB) are studied under vertical near-fault pulse-like and non-pulse-like ground motions. Ten ground motions of the Chichi earthquake event are selected and divided into two groups. The large-span plane RCFB structure is simplified from a practical engineering structure and used to perform a dynamic time-history analysis. The vertical mid-beam displacement and the axial pressure at the base of the bottom column of the structure are compared under vertical pulse-like and vertical non-pulse-like ground motions, and the effects of the structural system parameters on the vertical mid-beam displacement are analyzed. This study shows that the vertical earthquake response of a large-span RCFB structure is significant, especially under pulse-like ground motions, and that the structural system parameters and the impulsive effect of ground motion exhibit a distinct coupled effect on the vertical response. Optimizing the location of haunch braces is very critical in RCFB structural design

Earthquake response of large-span reinforced concrete structures with haunch braces under vertical ground motions

A new type of reinforced concrete (RC) frame system with diagonal haunch braces is introduced in a large-span sports education building. In this paper, the nonlinear dynamic responses of the large-span RC frame structures with diagonal haunch braces (RCFB) are studied under vertical near-fault pulse-like and non-pulse-like ground motions. Ten ground motions of the Chichi earthquake event are selected and divided into two groups. The large-span plane RCFB structure is simplified from a practical engineering structure and used to perform a dynamic time-history analysis. The vertical mid-beam displacement and the axial pressure at the base of the bottom column of the structure are compared under vertical pulse-like and vertical non-pulse-like ground motions, and the effects of the structural system parameters on the vertical mid-beam displacement are analyzed. This study shows that the vertical earthquake response of a large-span RCFB structure is significant, especially under pulse-like ground motions, and that the structural system parameters and the impulsive effect of ground motion exhibit a distinct coupled effect on the vertical response. Optimizing the location of haunch braces is very critical in RCFB structural design