Effect of Gd on neutron absorption properties and electrochemical corrosion behavior of Zr-Gd alloy in boiling concentrated HNO3

A Zr-Gd alloy with neutron poisoning properties and resistance to boiling concentrated HNO3 corrosion was developed based on a corrosion-resistant Zr-702 alloy to meet the demand for neutron shielding in the closed-loop treatment of spent fuel and the nuclear chemical industry.In this study,1 wt.%,3 wt.%,5 wt.%,7 wt.%,and 9 wt.%Zr-Gd alloys were designed and fabricated with Zr-702 as the control element.The electrochemical behavior of the Zr-Gd alloys in boiling concentrated HNO3 was investigated,and the neutron shielding effect on plate thickness and Gd content was simulated.The experimental results demonstrate that the corrosion resistance of the alloy decreased slightly before~7-9 wt.%with increasing Gd content;this is the inflection point of its corrosion resistance.The alloy uniformly dissolved the Gd content that could not be dissolved in the Zr lattice,resulting in numerous micropores on the passivation coating,which deteriorated and accelerated the corrosion rate.The MCNP simulation demonstrated that when the Gd content was increased to 5 wt.%,a 2-mm-thick plate can shield 99.9%neutrons;an alloy with a Gd content≥7 wt.%required only a 1-mm-thick plate,thereby showing that the addition of Gd provides an excellent neutron poisoning effect.Thus,the corrosion resistance and neutron shielding performance of the Zr-Gd alloy can meet the harsh service requirements of the nuclear industry.

Electroacupuncture alleviates cerebral ischemia and reperfusion injury via modulation of the ERK1/2 signaling pathway

Electroacupuncture（EA） has anti-oxidative and anti-inflammatory actions,but whether the neuroprotective effect of EA against cerebral ischemia-reperfusion（I/R） injury involves modulation of the extracellular regulated kinase 1/2（ERK1/2） signaling pathway is unclear.Middle cerebral artery occlusion（MCAO） was performed in Sprague-Dawley rats for 2 hours followed by reperfusion for 24 hours.A 30-minute period of EA stimulation was applied to both Baihui（DU20） and Dazhui（DU14） acupoints in each rat（10 mm EA penetration depth,continuous wave with a frequency of 3 Hz,and a current intensity of 1–3 m A） when reperfusion was initiated.EA significantly reduced infarct volume,alleviated neuronal injury,and improved neurological function in rats with MCAO.Furthermore,high m RNA expression of Bax and low m RNA expression of Bcl-2 induced by MCAO was prevented by EA.EA substantially restored total glutathione reductase（GR）,glutathione（GSH） and glutathione peroxidase（GSH-Px） levels.Additionally,Nrf2 and glutamylcysteine synthetase（GCS） expression levels were markedly increased by EA.Interestingly,the neuroprotective effects of EA were attenuated when ERK1/2 activity was blocked by PD98059（a specific MEK inhibitor）.Collectively,our findings indicate that activation of the ERK1/2 signaling pathway contributes to the neuroprotective effects of EA.Our study provides a better understanding of the regulatory mechanisms underlying the therapeutic effectiveness of EA.

Eco-friendly Synthesis of Cyclododecanone from Cyclododecatriene

An eco-friendly synthesis of cyclododecanone (CDON) from cyclododecatriene (CDT) is described. Selec- tive epoxidation of CDT with hydrogen peroxide using hexadecyl trimethyl ammonium heteropolyphospha- totungstate [(n-C16H33NMe3)3PW4O16, HAHPT] as catalyst and water as solvent followed by the hydrogena- tion on Raney nickel catalyst gave cyclododecanol (CDOL). The latter was oxidized with hydrogen peroxide using HAHPT as catalyst and a mixture of water and t-butanol as solvent to afford CDON. The total yield was 53.4% under the optimum reaction conditions.

Experimental study of the azimuthal performance of 3D acoustic transmitter stations

Better well logging techniques for geologic investigations are urgently needed to identify and evaluate complex reservoirs.We describe a new type of 3D transmitter station with corresponding circuits and bodies.They can be used in a promising new technique of acoustic reflection well logging,that features better azimuthal detection capabilities,as well as better investigation depth.The transmitter stations consist of three-level subarrays that can radiate acoustic energy in any required azimuth of 3D space by circularly exciting various combinations at different levels.We tested the 3D acoustic transmitter stations and obtained laboratory directivity measurements with the3 D acoustic transmitter stations for the first time.The results show that the 3-d B beam width in the horizontal plane ranges from 59° to 67° as a result of phase-delayed excitation.The main beam is steered in the vertical plane at a deflection angle that ranges from 0° to 16° when the delay time of the excitation pulse between each pair of adjacent arc arrays is gradually adjusted.The 3-d B beam width is equal to 11°,whereas the deflection angle in the vertical plane is equal to 14°.Each of the four third-level subarrays in the same circumferential direction display consistent horizontal and vertical directivities,thus satisfying the requirements of azimuthal acoustic reflection logging.