Comparison analysis of superconducting solenoid magnet systems for ECR ion source based on the evolution strategy optimization

Shaoqing Wei,이상진 한국초전도.저온공학회 2015 한국초전도저온공학회논문지 Vol.17 No.2

Electron cyclotron resonance (ECR) ion source is an essential component of heavy-ion accelerator. For a given design, theintensities of the highly charged ion beams extracted from the source can be increased by enlarging the physical volume of ECRzone [1]. Several models for ECR ion source were and will be constructed depending on their operating conditions [2-4]. In thispaper three simulation models with 3, 4 and 6 solenoid system were built, but it’s not considered anything else except the number ofcoils. Two groups of optimization analysis are presented, and the evolution strategy (ES) is adopted as an optimization tool whichis a technique based on the ideas of mutation, adaptation and annealing [5]. In this research, the volume of ECR zone was calculatedapproximately, and optimized designs for ECR solenoid magnet system were presented. Firstly it is better to make the volume ofECR zone large to increase the intensity of ion beam under the specific confinement field conditions. At the same time the totalvolume of superconducting solenoids must be decreased to save material. By considering the volume of ECR zone and the totallength of solenoids in each model with different number of coils, the 6 solenoid system represented the highest coil performance. By the way, a certain case, ECR zone volume itself can be essential than the cost. So the maximum ECR zone volume for eachsolenoid magnet system was calculated respectively with the same size of the plasma chamber and the total magnet space. Bycomparing the volume of ECR zone, the 6 solenoid system can be also made with the maximum ECR zone volume.

Control the length of beam trajectory with a quadruple triplet for heavy ion accelerator

Shaoqing Wei,Zhan Zhang,Sangjin Lee,Do Gyun Kim,Jang Youl Kim 한국초전도저온학회 (구 한국초전도저온공학회) 2016 한국초전도저온공학회논문지 Vol.18 No.4

A Study on the Design of Full-LTS 18-GHz ECR Ion Source for Heavy Ion Accelerator

Shaoqing Wei,Sangjin Lee,Sukjin Choi Institute of Electrical and Electronics Engineers 2016 IEEE transactions on applied superconductivity Vol.26 No.4

<P>An electron cyclotron resonance (ECR) ion source is an essential component of the heavy ion accelerator. The intensity of the highly charged ion beams extracted from the source can be increased by enlarging the physical volume of the ECR zone, which is one of the key elements of the ECR ion source. The ECR zone locates in a minimum B field configuration that is created by solenoids and hexapole. For an 18-GHz ECR ion source, hexapole is generally made by a permanent magnet. In this paper, a low-temperature superconductor (LTS) magnet was used instead of a permanent magnet because its cost becomes higher and higher, and finally, the mechanical stress of hexapole would be enhanced. First, the hexapole-in-solenoid system and the solenoid-in-hexapole system with several numbers of solenoid coils were analyzed. Then, the most appropriate arrangements for ECR systems were selected. The total length of LTS wire was minimized with the ECR zone volume and the maximum magnetic field in hexapole, respectively, using the evolution strategy method. Finally, the optimized design for a full-LTS 18-GHz ECR ion source was presented.</P>

A study on the design of hexapole in an 18-GHz ECR ion source for heavy ion accelerators

Shaoqing Wei,Zhan Zhang,Sangjin Lee,Sukjin Choi 한국초전도저온학회 (구 한국초전도저온공학회) 2016 한국초전도저온공학회논문지 Vol.18 No.2

Behavior of mercury release during thermal decomposition of coals

Shaoqing Guo,Yong Xiao,Jianli Yang,Zhenyu Liu 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

The mercury release behavior during thermal decomposition of three Chinese coals with different types was studied under nitrogen, carbon dioxide and air at temperatures of 800, 900, 1,000 and 1,100℃. The thermal treatment experiments were carried out in a quartz tube reactor. Results showed that the release ratio of total mercury during thermal decomposition of coals increases with the increasing temperature. The order of the amount of mercury released under the three atmospheres is nitrogen<carbon dioxide<air for all three coals during thermal decomposition. This indicates that air and carbon dioxide can promote the mercury release due to their reactivity with coal. However, the order of amount of elemental mercury released under the three atmospheres is nitrogen>carbon dioxide>air for all three coals. The release behavior of the total mercury under air is independent of the coal type. Under the other two atmospheres the release behavior is distinguished by the coal type.

The catalytic performance of methylation of naphthalene with methanol over SAPO-11 zeolites synthesized with different Si content

Shaoqing Guo,Liangfu Zhao,Xiaoxiao Wang,Fang Guo,Xianxian Wei,Zhenmin Liu,Wei Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7

A series of SAPO-11 zeolites with different Si contents were prepared by hydrothermally synthesized method. They were characterized by ICP, XRD, SEM, FT-IR, N2 adsorption-desorption, NH3-TPD and 29Si MAS NMR, and evaluated by the methylation of naphthalene with methanol to 2,6-dimethylnaphthalene (2,6-DMN). According to XRD and SEM results, the crystallinity of SAPO-11 sample increased with increase of the Si content until the SiO2/Al2O3 ratio was up to 0.2. However, a reduction in the crystallinity was observed with further increase of the Si content of the synthesis. N2 adsorption-desorption results showed that all the samples possessed micropores and secondary mesopores. SAPO-11 sample with SiO2/Al2O3 ratio of 0.2 exhibited the largest secondary mesopores size distributions. NH3-TPD and 29Si MAS NMR showed that the Si content was incorporated into the framework affecting not only the acid sites but also the acid strength of SAPO-11. SAPO-11 with SiO2/Al2O3 ratio of 0.2 presented the high catalytic performances for the methylation of naphthalene, which was mainly attributed to the amount of secondary mesopores in the SAPO-11 zeolite.

Effects of N-Acetylcysteine on Nicotinamide Dinucleotide Phosphate Oxidase Activation and Antioxidant Status in Heart, Lung, Liver and Kidney in Streptozotocin-Induced Diabetic Rats

Shaoqing Lei,Zhengyuan Xia,Huimin Liu,Hong Yu,Hui Wang,Yanan Liu 연세대학교의과대학 2012 Yonsei medical journal Vol.53 No.2

Purpose: Hyperglycemia increases reactive oxygen species (ROS) and the resulting oxidative stress plays a key role in the pathogenesis of diabetic complications. Nicotinamide dinucleotide phosphate (NADPH) oxidase is one of the major sources of ROS production in diabetes. We, therefore, examined the possibility that NADPH oxidase activation is increased in various tissues, and that the antioxidant N-acetylcysteine (NAC) may have tissue specific effects on NADPH oxidase and tissue antioxidant status in diabetes. Materials and Methods: Control (C) and streptozotocin-induced diabetic (D) rats were treated either with NAC (1.5 g/kg/day) orally or placebo for 4 weeks. The plasma, heart, lung, liver, kidney were harvested immediately and stored for biochemical or immunoblot analysis. Results: levels of free 15-F2t-isoprostane were increased in plasma, heart, lung, liver and kidney tissues in diabetic rats, accompanied with significantly increased membrane translocation of the NADPH oxidase subunit p67phox in all tissues and increased expression of the membrane-bound subunit p22phox in heart, lung and kidney. The tissue antioxidant activity in lung, liver and kidney was decreased in diabetic rats, while it was increased in heart tissue. NAC reduced the expression of p22phox and p67phox, suppressed p67phox membrane translocation, and reduced free 15-F2t-isoprostane levels in all tissues. NAC increased antioxidant activity in liver and lung, but did not significantly affect antioxidant activity in heart and kidney. Conclusion: The current study shows that NAC inhibits NADPH oxidase activation in diabetes and attenuates tissue oxidative damage in all organs, even though its effects on antioxidant activity are tissue specific.

A Fluorinated Polythiophene Derivative with Stabilized Backbone Conformation for Highly Efficient Fullerene and Non-Fullerene Polymer Solar Cells

Zhang, Shaoqing,Qin, Yunpeng,Uddin, Mohammad Afsar,Jang, Bomee,Zhao, Wenchao,Liu, Delong,Woo, Han Young,Hou, Jianhui American Chemical Society 2016 Macromolecules Vol.49 No.8

<P>Here, taking a polythiophene derivative (PBDD4T) as a starting polymer, we tried to increase the rotation barrier and hence stabilize its backbone conformation by introducing fluorine into the beta and beta'-position of the alpha-linked bithiophene segments and then synthesized a new polymer named as PBDD4T-2F. Our results demonstrate that the rotation barrier between the a-linked bithiophene significantly increases after the fluorination, so PBDD4T-2F has a more stable backbone conformation than PBDD4T. Compared to PBDD4T, PBDD4T-2F shows stronger aggregation effect in solution state and more compact pi-pi stacking in solid thin film and also possesses deeper HOMO level. These properties make PBDD4T-2F being an ideal donor material in PSCs. When blended with PC71BM, a fullerene acceptor, the PBDD4T-2F-based device showed a power conversion efficiency (PCE) of 9.04%, which is 38% higher than that of the PBDD4T-based device; when blended with ITIC, a non-fullerene acceptor, the PBDD4T-2F-based device showed a PCE of 8.69%, which is almost 20 times higher than that of the PBDD4T-based device. What is more, the tandem cell, in which the blend of PBDD4T-2F:PC61BM was used for making the front subcell, exhibited a high PCE of 10.12%. The photovoltaic results indicate that the fluorination is an effective method to enhance interchain pi-pi interaction for the polythiophene and hence to tune its photovoltaic properties in PSCs, especially for the fullerene-free device based on ITIC.</P>

A Study on the Sextupole Design with Iron Yoke Inside Solenoids for 56 GHz ECR Ion Sources

Wei, Shaoqing,Zhang, Zhan,Lee, Sangjin Institute of Electrical and Electronics Engineers 2018 IEEE transactions on applied superconductivity Vol.28 No.3

<P>The third generation of electron cyclotron resonance (ECR) ion sources is in operation or under development in the world. The fourth generation ECR ion sources are expected to operate at a heating radio frequency greater than 40 GHz, requiring a higher confinement field. Such requirements provide the motivation to design the structure of the fourth generation ECR ion sources. The Nb<SUB>3</SUB>Sn wire, which can generate fields in the 10–20 T range, is considered to construct the magnet coil analyzed in this study. First, for both solenoid-in-sextupole structure and sextupole-in-solenoid structure, the critical current of materials and the local magnetic field are analyzed and compared. By the comparison, sextupole-in-solenoid structure is selected to construct sextupole magnet for 56 GHz ECR ion source. Considering the characteristics of the wire and the Lorentz force on sextupole ends, iron yoke is considered to be added around sextupole to provide a structure for the sextupole coils. Then, the confinement fields and the safety margin of the wire are analyzed and compared using models with and without the iron yoke. Finally, a design of the sextupole with a shorter iron yoke is presented in this paper. With the suggested sextupole design, the length of the sextupole and the total size of the ECR ion source can be reduced.</P>

Control the length of beam trajectory with a quadruple triplet for heavy ion accelerator

Wei, Shaoqing,Zhang, Zhan,Lee, Sangjin,Kim, Do Gyun,Kim, Jang Youl The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.4

Beam trajectory is needed to be controlled in heavy ion accelerator system. Quadruple magnets are widely used in heavy ion accelerator for focusing the transporting particles. A quadruple triplet system which consists of three consecutive quadrupoles, Q1, Q2 and Q3, is used to control beam trajectory at a focused position. Q1 and Q3 have symmetry with respect to Q2. The beam trajectory in magnet system is affected by higher order fields existed in real fields. For quadrupoles, the representation simulation of beam trajectory was carried out to study the beam trajectory and to estimate an effect of higher order field in triplet system. SCALA program was used to simulate the beam trajectory in $Opera^{TM}$. SCALA can analyze a large number of beam trajectories at the same time by adjusting the size of finite element of the emitter. With $Opera^{TM}$ and $Matlab^{TM}$ programs, the position of focused beam spot in quadruple triplet system can be increased or decreased using evolution strategy (ES) method, therefore the length of triplet system can be controlled. Finally, the quadruple triplet system with the appropriate length and expected beam spot range was suggested in this paper.