Dissolution-precipitation mechanism of self-propagating high-temperature synthesis of TiC-Cu cermets

The mechanism of self-propagating high-temperature synthesis （SHS） of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scanning electron microscope （SEM） with energy dispersive X-ray （EDX） spectrometry, and the combustion temperature was measured. The results showed that the combustion reaction started with local formation of Ti-Cu melt and could be described with the dissolution-precipitation mechanism, namely, Ti, Cu, and C particles dissolved into the Ti-Cu solution and TiC particles precipitated in the saturated Ti-Cu-C liquid solution. The local formation of Ti-Cu melt resulted from the solid diffusion between Ti and Cu particles.

Warm dense matter research at HIAF

The research activities on warm dense matter driven by intense heavy ion beams at the new project High Intensity heavy-ion AcceleratorFacility (HIAF) are presented. The ion beam parameters and the simulated accessible state of matter at HIAF are introduced, respectively. Theprogresses of the developed diagnostics for warm dense matter research including high energy electron radiography, multiple-channel pyrometer,in-situ energy loss and charge state of ion detector are briefly introduced.

强流重离子加速器,肩负探索未知世界新使命

重大科技基础设施是为探索未知世界、发现自然规律、实现技术变革提供极限研究手段的大型复杂科学研究系统,是突破科学前沿,解决经济社会发展和国家安全重大科技问题的物质技术基础.《国家重大科技基础设施建设中长期规划(2012-2030年)》明确提出,瞄准科技前沿研究和国家重大战略需求,根据重大科技基础设施发展的国际趋势和国内基础,总体部署16项重大科技基础设施建设项目.强流重离子加速器装置(high intensity heavy-ion accelerator facility,HIAF)作为核物理科学领域的重要部署被列为建设重点项目之一,并于2018年12月底在广东惠州正式启动建设.图1为HIAF装置效果图.

Conceptual design of the HIRFL-CSR external-target experiment

One of the main purposes of heavy-ion collisions over a wide range of beam energy is to study the bulk properties of strong interaction matter and understand the Quantum Chromo Dynamics(QCD)phase diagram,which carries wealth of information of the phase transition and the possibly existing critical point of the strongly interacting system[1].Such system exists as hadron gases at lower temperature and low baryon density.By increasing the temperature or density,the boundary of the hadrons disappears and the confined quarks

Electron-ion collider in China

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei.As a future high energy nuclear physics project,an Electron-ion collider in China(EicC)has been proposed.It will be constructed based on an upgraded heavy-ion accelerator,High Intensity heavy-ion Accelerator Facility(HIAF)which is currently under construction,together with a new electron ring.The proposed collider will provide highly polarized electrons(with a po-larization of 80%)and protons(with a polarization of 70%)with variable center of mass energies from 15 to 20 GeV and the luminosity of(2–3)×1033 cm^(−2)·s^(−1).Polarized deuterons and Helium-3,as well as unpolarized ion beams from Carbon to Uranium,will be also available at the EicC.The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region,including 3D tomography of nucleon;the partonic structure of nuclei and the parton interaction with the nuclear environment;the exotic states,especially those with heavy flavor quark contents.In addition,issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC.In order to achieve the above-mentioned physics goals,a hermetical detector system will be constructed with cutting-edge technologies.This document is the result of collective contributions and valuable inputs from experts across the globe.The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States.The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.

Weak-reduction graphene oxide membrane for improving water purification performance

Two-dimensional(2 D) materials are promising candidates for advanced water purification membranes.In this work, UV reduced GO(Ur GO) membranes on the support of polyvinylidene fluoride(PVDF) had been fabricated for wastewater treatment. The reduction degree of GO membrane on the effect of water purification performance was investigated, and it was found that the weak-reduction GO membrane exhibited the optimal performance of removing pollutant from wastewater than GO membrane. Besides,scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectra and contact angle tests were used to characterize the physical and chemical properties of the Ur GO membranes, and the permeance and rejection ability of the as-prepared filtration membranes were determined. Due to the weak-reduction of GO, pristine graphitic sp2 domains increased with slightly decreasing D-spacing. Thus,the Ur GO membrane showed a higher water flux of 38.27 L m-2h-1 bar-1, which was improved more than 270% compared to GO membrane, and dyes rejection increased. Those outstanding performances indicated that the Ur GO membrane could effectively regulate the contradiction of the trade-off balance between flux and rejection, and hold great potential in real-world waste-water purification.

CO2 corrosion behaviors of 13Cr steel in the high-temperature steam environment

The study aims to explore the corrosion behaviors of 13Cr steel in the high-temperature steam environment.The corrosion behaviors of 13Cr steel were tested in CO2 auxiliary steam drive environment simulated with the HTHP autoclave.The corrosion morphology and product composition were explored by SEM,EDS,XRD and XPS.The exploration results showed the corrosion rate of 13Cr steel in the high-temperature steam environment was less than 0.04 mm/a.The corrosion behaviors of 13Cr steel were mainly affected by temperature and chloride ion concentration.Temperature inhibited steam condensation and the compactness of Cr-rich layer.With the increase in temperature,more droplets were adsorbed on the surface of 13Cr steel and the compactness of the Crrich layer is worse.Chloride ions affects the activity of Fe atoms in the metal matrix.When chloride concentration increased,Fe^2+concentration in the solution and FeCO3 content in the rich-Cr layer were increased and the rich-Cr layer became looser.

High energy density physics research at IMP,Lanzhou, China

Recent research activities relevant to high energy density physics(HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with the fast extracted high energy carbon ion beam from the Cooling Storage Ring is discussed. Investigation of the low energy heavy ion beam and plasma interaction is reported. With HEDP research as one of the main goals, the project HIAF(High Intensity heavy-ion Accelerator Facility), proposed by the Institute of Modern Physics as the 12 th five-year-plan of China, is introduced.

Quantifying Hypochlorous Acid Concentration in Environmental Water Using Smartphone Colorimetry

In this study,we developed an eff ective method to detect hypochlorite acid(HClO)by using methylene blue(MB)derivative(BPY1).BPY1 was selectively oxidized through HClO,and the solution color changed from colorless to blue.In the presence of HClO,the ultraviolet–visible(UV–vis)spectra and concentration of HClO had a linear relationship with a detection limit of 0.5μM.Furthermore,a test paper for HClO monitoring was successfully prepared using the BPY1 probe,and the observed detection limit by the naked eye was estimated at 5μM.Additionally,using the BPY1 probe,HClO could also be detected through smartphone colorimetry,and the method showed a good recovery ranging from 98.7 to 104.0%for HClO detection in an actual water sample.Especially for developing countries,such a low-cost and highly sensitive detection method provides a simple and practical method for monitoring HClO in water.

β-decay study of neutron-rich nucleus ^(34)Al

The'island of inversion'has been known for over a quarter century,since Warburton et al.[1]proposed that nuclei with intruder ground states would constitute a 3×3 square with Z=10-12,N=20-22 in 1990.Uncovering the underlying inversion mechanism and exploring the scope of the island have attracted significant theoretical and experimental efforts in the following years.Now it is well known that the reduction of N=20 shell gap,which is likely caused by the