Measurements of proton beam flux and energy of APEP using foil activation technique

Li Wenlin,Dong Qifan,Jing Hantao,Ou Li,Tan Zhixin,Zhuang Sixuan,Wu Qingbiao 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.1

The activation method of metallic foils is an important technique to measure the flux and energy of proton beams. In this paper, the method was used to measure the CSNS APEP proton flux at seven nominal proton energies ranging from 10 MeV to 70 MeV for beam spot sizes of the 20 mm × 20 mm and 50 mm × 50 mm. The reactions of natTi(p, x)48V, natNi(p, x)57Ni, natCu(p, x)58Co, and 27Al(p, x)24Na were employed to measure the proton beam flux with a range of 107-109 p/cm2/s. Furthermore, we also proposed a method using the activity ratio with a stacked-foil target to determine the energy spread of a Gaussian-like distribution for different nominal proton energies. The optimal combinations of Al, Cu, Ti, Ni, Mo, Fe, Nb, and In foils were adopted for the proton energies. The measured energy spreads for degraded beams of 30 MeV–70 MeV were found to be smaller than 10.00%.

The Production of Bioflocculants by Bacillus licheniformis Using Molasses and Its Application in the Sugarcane Industry

Xiaoling Zhuang,Yuanpeng Wang,Qingbiao Li,Shan Yan,Ning He 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.5

A bioflocculant produced by B. licheniformis was investigated with regard to a low-cost culture medium and its industrial application. Molasses replaced sucrose as the sole carbon source in bioflocculant fermentation. The optimum low-cost culture medium was determined to be composed of 20 g/L molasses, 0.4 g/L urea, 0.4 g/L NaCl,0.2 g/L KH2PO4, 1.6 g/L K2HPO4, and 0.2 g/L MgSO4. The bioflocculant from B. licheniformis was then applied to treat sugarcane-neutralizing juice to remove colloids,suspended particles, and coloring matters in a sugar refinery factory. The optimal operation conditions were a bioflocculant dosage of 21 U/mL, pH 7.3 and a heating temperature of 100oC. The color and turbidity of the sugarcane juice reached IU 1267 and IU 206, respectively,after clarification with the bioflocculant; these values were almost the same as those acquired following treatment with polyacrylamide (PAM), the most widely applied flocculant in sugar industries. These results suggest the great potential for use of bioflocculants in the sugar refinery process. A bioflocculant produced by B. licheniformis was investigated with regard to a low-cost culture medium and its industrial application. Molasses replaced sucrose as the sole carbon source in bioflocculant fermentation. The optimum low-cost culture medium was determined to be composed of 20 g/L molasses, 0.4 g/L urea, 0.4 g/L NaCl,0.2 g/L KH2PO4, 1.6 g/L K2HPO4, and 0.2 g/L MgSO4. The bioflocculant from B. licheniformis was then applied to treat sugarcane-neutralizing juice to remove colloids,suspended particles, and coloring matters in a sugar refinery factory. The optimal operation conditions were a bioflocculant dosage of 21 U/mL, pH 7.3 and a heating temperature of 100oC. The color and turbidity of the sugarcane juice reached IU 1267 and IU 206, respectively,after clarification with the bioflocculant; these values were almost the same as those acquired following treatment with polyacrylamide (PAM), the most widely applied flocculant in sugar industries. These results suggest the great potential for use of bioflocculants in the sugar refinery process.

Preparation and characterization of electrospun Ag/polyacrylonitrile composite nanofibers

Jie Bai,Yaoxian Li,Qingbiao Yang,Shan Wang,김학용 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.8

Novel composite nanofibers consisting of Ag nanoparticles and polyacrylonitrile (PAN) were fabricated successfully. The Raman properties of these Ag/PAN nanofibers were studied at low temperatures, which showed good Raman characteristics. In the process, a PAN solution containing Ag ions was directly electrospun to obtain nanofiber films containing Ag ions, and the Ag ions of resulting composite nanofibers were reduced to Ag nanoparticles in N_2H_5OH aqueous solution. Then, we treated Ag/PAN composite nanofibers at 100 ℃, 200 ℃, 400 and 600 ℃, respectively. The Ag/PAN nanocomposite film was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) patterns and surface-enhanced Raman scattering (SERS) spectroscopy.

Effects of Extrusion Temperature on the Properties of a 0.5 wt.% GNP/Al Composite in Porthole Die Extrusion

Shumei Lou,Yiming Li,Baojia Cheng,Lingwei Ran,Yue Wang,Leyao Xu,Ben Ma,Chungjian Su,Qingbiao Wang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

A 0.5 wt% GNP/Al composite was prepared by powder metallurgy and hot pressing. The numerical simulations and experimentsof porthole die extrusion were performed at 440 °C, 460 °C, 480 °C and 500 °C. The effect of extrusion temperatureon the microstructure and mechanical properties of the composites was studied. The results showed that the composite nearthe welding zone underwent dynamic recrystallization due to the large strain to form fine grains, some of which grew tocoarse grains because of the local high temperature. The extrusion temperature influenced the properties of the 0.5 wt%GNP/Al composite along both the extrusion and transverse directions. This influence is combined with synergistic effectson the recrystallization of the grain, fluidity and plasticity of the matrix, determined by the delamination, distribution andstructure of graphene and welding behavior in the welding zone. Therefore, the comprehensive mechanical properties ofthe composite reached the highest values in the extrusion direction and the transverse direction at 460 °C; the TEM imagesshowed that the graphene and aluminum matrix were in contact with each other via a small wavy transition overlapping zoneor that interaction forces caused by welding and shearing allowed the formation of a direct interface with the Al matrix. Thedeformed graphene formed a good interface with the matrix, ensuring outstanding mechanical properties in the welding zone.

Optimization of Medium Components for Plasmid Production by Recombinant E. coli DH5α pUK21CMVβ1.2

Yinghua Lu,Shuzhen Zheng,Karl Friehs,Ning He,Xu Deng,Qingbiao Li,Zheng He,Chenyun Xu 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

In this study we investigated the effects of carbon and nitrogen sources, and the carbon to nitrogen ratio (C:N) of growth medium on the production of plasmid DNA by pUK21CMVβ1.2 harbouring recombinant E. coli. The results indicated that sucrose and casein peptone were the most suitable carbon and nitrogen sources, respectively, for plasmid production, and the plasmid concentration was significantly influenced by the C:N ratio. A Box-Behnken design and surface response methodology were employed to formulate the optimal medium. In the optimized medium, a plasmid concentration of 51.80 mg/L and a plasmid selectivity of 23.49 mg/g were achieved after 24 h of incubation. These values were approximately 3.5 and 1.7 times higher, respectively, than those obtained on the original LB medium.

Optimization of Medium Components for Plasmid Production by Recombinant E. coli $DH5{\alpha}$ $pUK21CMV{\beta}1.2$

Zheng, Shuzhen,Friehs, Karl,He, Ning,Deng, Xu,Li, Qingbiao,He, Zheng,Xu, Chenyun,Lu, Yinghua Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

In this study we investigated the effects of carbon and nitrogen sources, and the carbon to nitrogen ratio (C:N) of growth medium on the production of plasmid DNA by $pUK21CMV{\beta}1.2$ harbouring recombinant E. coli. The results indicated that sucrose and casein peptone were the most suitable carbon and nitrogen sources, respectively, for plasmid production, and the plasmid concentration was significantly influenced by the C:N ratio. A Box-Behnken design and surface response methodology were employed to formulate the optimal medium. In the optimized medium, a plasmid concentration of 51.80mg/L and a plasmid selectivity of 23.49mg/g were achieved after 24h of incubation. These values were approximately 3.5 and 1.7 times higher, respectively, than those obtained on the original LB medium.

Push–Pull Type Oligo(<i>N</i>-annulated perylene)quinodimethanes: Chain Length and Solvent-Dependent Ground States and Physical Properties

Zeng, Zebing,Lee, Sangsu,Son, Minjung,Fukuda, Kotaro,Burrezo, Paula Mayorga,Zhu, Xiaojian,Qi, Qingbiao,Li, Run-Wei,Navarrete, Juan T. Ló,pez,Ding, Jun,Casado, Juan,Nakano, Masayoshi,Kim, Dongho American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.26

<P>Research on stable open-shell singlet diradicaloids recently became a hot topic because of their unique optical, electronic, and magnetic properties and promising applications in materials science. So far, most reported singlet diradicaloid molecules have a symmetric structure, while asymmetric diradicaloids with an additional contribution of a dipolar zwitterionic form to the ground state were rarely studied. In this Article, a series of new push pull type oligo(N-annulated perylene)quinodimethanes were synthesized. Their chain length and solvent-dependent ground states and physical properties were systematically investigated by various experimental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device, Raman spectroscopy, and electrochemistry. It was found that with extension of the chain length, the diradical character increases while the contribution of the zwitterionic form to the ground state becomes smaller. Because of the intramolecular charge transfer character, the physical properties of this push pull system showed solvent dependence. In addition, density functional theory calculations on the diradical character and Hirshfeld charge were conducted to understand the chain length and solvent dependence of both symmetric and asymmetric systems. Our studies provided a comprehensive understanding on the fundamental structure and environment property relationships in the new asymmetric diradicaloid systems.</P>