The Development of High-Current Power Supply System for Electrolytic Copper Foil

An Luo,Fujun Ma,Qiaopo Xiong,Zhixing He 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A 6.5 V/50 kA high-frequency switching power supply (HSPS) system composed of 10 power modules is developed to meet the requirements of copper-foil electrolysis. The power module is composed of a two-leg pulse width modulation (PWM) rectifier and a DC/DC converter. The DC/DC converter adopts two full-wave rectifiers in parallel to enhance the output. For the two-leg PWM rectifier, the ripple of the DC-link voltage is derived. A composite control method with a ripple filter is then proposed to effectively improve the performance of the rectifier. To meet the process demand of copper-foil electrolysis, the virtual impedance-based current-sharing control method with load current full feedforward is proposed for n-parallel DC/DC converters. The roles of load current feedforward and virtual impedance are analyzed, and the current-sharing control model of the HSPS system is derived. Virtual impedance is used to adjust the current-sharing impedance without changing the equivalent output impedance, which can effectively reduce current-sharing errors. Finally, simulation and experimental results verify the structure and control method.

A New Approach to Fuzzy Modeling and Control for Nonlinear Dynamic Systems: Neuro-Fuzzy Dynamic Characteristic Modeling and Adaptive Control Mechanism

Xiong Luo,Zengqi Sun,Fuchun Sun 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.1

The study on nonlinear control system has received great interest from the international research field of automatic engineering. There are currently some alternative and complementary methods used to predict the behavior of nonlinear systems and design nonlinear control systems. Among them, characteristic modeling (CM) and fuzzy dynamic modeling are two effective methods. However, there are also some deficiencies in dealing with complex nonlinear system. In order to overcome the deficiencies, a novel intelligent modeling method is proposed by combining fuzzy dynamic modeling and characteristic modeling methods. Meanwhile, the proposed method also introduces the low-level learning power of neural network into the fuzzy logic system to implement parameters identification. This novel method is called neuro-fuzzy dynamic characteristic modeling (NFDCM). The neuro-fuzzy dynamic characteristic model based overall fuzzy control law is also discussed. Meanwhile the local adaptive controller is designed through the golden section adaptive control law and feedforward control law. In addition, the stability condition for the proposed closed-loop control system is briefly analyzed. The proposed approach has been shown to be effective via an example.

The Novel Infrared Target Localization Algorithm for Free Floating Space Robot

Xiong Luo,Xiaolu Jie,Huaping Liu,Fuchun Sun 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10

With regards to the complicated characteristic of outer space, the infrared target recognition system has been investigated for free floating space robot. A novel algorithm is proposed based on visual location method for free floating space robot. Firstly, we set an omnidirectional camera with fixed lens on the ceiling. Here, the free floating robot is moving on the platform. Especially, in order to reduce image noise, we fix an infrared filter in the lens. Then, we place a number of infrared-emitting diodes on the free floating space robot and the targets. Finally, we can get the accurate positions and angle information of the robot and the target according to the location of the infrared light. The experimental results prove that this approach presented in this paper is an effective method for target detection and static target capture for free floating space robot.

A Novel Data Fusion Scheme using Grey Model and Extreme Learning Machine in Wireless Sensor Networks

Xiong Luo,Xiaohui Chang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.3

With the increasing presence and adoption of wireless sensor networks (WSNs), the demand of data acquisition and data fusion are becoming stronger and stronger. In WSN, sensor nodes periodically sense data and send them to the sink node. Since the network consists of plenty of low-cost sensor nodes with limited battery power and the sensed data usually are of high temporal redundancy, prediction-based data fusion has been put forward as an important issue to reduce the number of transmissions and save the energy of the sensor nodes. Considering the fact that the sensor node usually has limited capabilities of data processing and storage, a novel prediction-based data fusion scheme using grey model (GM) and optimally pruned extreme learning machine (OP-ELM) is proposed. The proposed data fusion scheme called GM-OP-ELM uses a dual prediction mechanism to keep the prediction data series at the sink node and sensor node synchronous. During the data fusion process, GM is introduced to initially predict the data of next period with a small number of data items, and an OP-ELM-based single-hidden layer feedforward network (SLFN) is used to make the initial predicted value approximate its true value with extremely fast speed. As a robust and fast neural network learn-ing algorithm, OP-ELM can adaptively adjust the structure of the SLFN. Then, GM-OP-ELM can provide high prediction accuracy, low communication overhead, and good scalability. We evaluate the performance of GM-OP-ELM on three actual data sets that collected from 54 sensors deployed in the Intel Berkeley Research lab. Simulation results have shown that the proposed data fusion scheme can significantly reduce redundant transmissions and extend the lifetime of the whole network with low computational cost.

Seroprevalence of Toxoplasma gondii Infection in Wild Boars, Wild Rabbits, and Wild Chickens in Hubei Province, China

Houqiang Luo,Kun Li,Muhammad Shahzad,Hui Zhang,Yanfang Lan,Xiong Xiong 대한기생충학열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.1

The Development of High-Current Power Supply System for Electrolytic Copper Foil

Luo, An,Ma, Fujun,Xiong, Qiaopo,He, Zhixing The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A 6.5 V/50 kA high-frequency switching power supply (HSPS) system composed of 10 power modules is developed to meet the requirements of copper-foil electrolysis. The power module is composed of a two-leg pulse width modulation (PWM) rectifier and a DC/DC converter. The DC/DC converter adopts two full-wave rectifiers in parallel to enhance the output. For the two-leg PWM rectifier, the ripple of the DC-link voltage is derived. A composite control method with a ripple filter is then proposed to effectively improve the performance of the rectifier. To meet the process demand of copper-foil electrolysis, the virtual impedance-based current-sharing control method with load current full feedforward is proposed for n-parallel DC/DC converters. The roles of load current feedforward and virtual impedance are analyzed, and the current-sharing control model of the HSPS system is derived. Virtual impedance is used to adjust the current-sharing impedance without changing the equivalent output impedance, which can effectively reduce current-sharing errors. Finally, simulation and experimental results verify the structure and control method.

CMOS-compatible batch processing of monolayer MoS₂ MOSFETs

Xiong, Kuanchen,Kim, Hyun,Marstell, Roderick J,Gö,ritz, Alexander,Wipf, Christian,Li, Lei,Park, Ji-Hoon,Luo, Xi,Wietstruck, Matthias,Madjar, Asher,Strandwitz, Nicholas C,Kaynak, Mehmet,Lee, Young IOP 2018 Journal of Physics. D, Applied Physics Vol.51 No.15

<P>Thousands of high-performance 2D metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on wafer-scale chemical vapor deposited MoS<SUB>2</SUB> with fully-CMOS-compatible processes such as photolithography and aluminum metallurgy. The yield was greater than 50% in terms of effective gate control with less-than-10 V threshold voltage, even for MOSFETs having deep-submicron gate length. The large number of fabricated MOSFETs allowed statistics to be gathered and the main yield limiter to be attributed to the weak adhesion between the transferred MoS<SUB>2</SUB> and the substrate. With cut-off frequencies approaching the gigahertz range, the performances of the MOSFETs were comparable to that of state-of-the-art MoS<SUB>2</SUB> MOSFETs, whether the MoS<SUB>2</SUB> was grown by a thin-film process or exfoliated from a bulk crystal.</P>

Role of Graphene in Water-Assisted Oxidation of Copper in Relation to Dry Transfer of Graphene

Luo, Da,You, Xueqiu,Li, Bao-Wen,Chen, Xianjue,Park, Hyo Ju,Jung, Minbok,Ko, Taeg Yeoung,Wong, Kester,Yousaf, Masood,Chen, Xiong,Huang, Ming,Lee, Sun Hwa,Lee, Zonghoon,Shin, Hyung-Joon,Ryu, Sunmin,Kwak American Chemical Society 2017 Chemistry of materials Vol.29 No.10

<P>The process of oxidation of a copper surface coated by a layer of graphene in water-saturated air at 50 degrees C was studied where it was observed that oxidation started at the graphene edge and was complete after 24 h. Isotope labeling of the oxygen gas and water showed that the oxygen in the formed copper oxides originated from water and not from the oxygen in air for both Cu and graphene-coated Cu, and this has interesting potential implications for graphene as a protective coating for Cu in dry air conditions. We propose a reaction pathway where surface hydroxyl groups formed at graphene edges and defects induce the oxidation of Cu. DFT simulation shows that the binding energy between graphene and the oxidized Cu substrate is smaller than that for the bare Cu substrate, which facilitates delamination of the graphene. Using this process, dry transfer is demonstrated using poly(bisphenol A carbonate) (PC) as the support layer. The high quality of the transferred graphene is demonstrated from Raman maps, XPS, STM, TEM, and sheet resistance measurements. The copper foil substrate was reused without substantial weight loss to grow graphene (up to 3 cycles) of equal quality to the first growth after each cycle. It was found that dry transfer yielded graphene with less Cu impurities as compared to methods using etching of the Cu substrate. Using PC yielded graphene with less polymeric residue after transfer than the use of poly(methyl methacrylate) (PMMA) as the supporting layer. Hence, this dry and clean delamination technique for CVD graphene grown on copper substrates is highly advantageous for the cost-effective large-scale production of graphene, where the Cu substrate can be reused after each growth.</P>

Kidney-sparing Management Versus Nephroureterectomy for Upper Tract Urothelial Carcinoma: a Systematic Review and Meta-analysis

Luo, You,She, Dong-Li,Xiong, Hu,Fu, Sheng-Jun,Yang, Li Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.14

Purpose: To evaluate and update evidence for prognostic effects of kidney-sparing (KS) management and nephroureterectomy (NU) for upper tract urothelial carcinomas. Materials and Methods: Pubmed, Embase and the Cochrane Library were retrieved for the identification of comparative studies of kidney-sparing procedure and nephroureterectomy for upper tract urothelial carcinoma prior to December 2014. The data were extracted independently by 2 reviewers and the quality of the included studies was assessed. Review Manager 5.3 and STATA 13 were used to perform the meta-analysis. Results: Twenty-three observational studies including 1,587 KS and 3,996 NU were evaluated. The results of the meta-analysis showed that nephroureterectomy had no significant benefit with regard to intravesical recurrence (IRFS), metastasis (MFS), cancer specific survival (CSS) and overall survival (OS) except the total tumor recurrence (RFS) when compared with kidney sparing management. The respectively pooled outcomes were HR 1.36 (0.69-2.68, P=0.38) for IRFS, 1.09 (0.59-2.01, P=0.78) for MFS, 1.17 (0.77-1.79, P=0.47) for CSS, 1.50 (0.90-2.48, P=0.12) for OS and 1.61 (1.03-2.51, P=0.04) for RFS. Conclusions: On the whole, kidney-sparing management had equivalent prognostic effect on upper tract urothelial carcinoma as the standard nephroureterectomy except in tumor recurrence. However, the results should be interpreted with caution for lack of stage and grade stratification and multi-center randomized controlled trials are still needed to verify our results.

Mechanical Properties and Strengthening Mechanism of Aluminum Matrix Composites Reinforced by High-entropy Alloy Particles

Kaiguang Luo,Shilei Liu,Hanqing Xiong,Yun Zhang,Charlie Kong,Hailiang Yu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

1 − 6 wt% Al0.5CoCrFeNihigh-entropy alloy particles (HEAp)/AA1050 aluminum matrix composites (AMCs) were preparedby stir casting process. The effect of HEAp mass fractions on microstructure and mechanical properties of the AMCswas studied. The results showed that with the increase in HEAp, the grains were obviously refined, and the ultimate tensilestrength (UTS) was gradually increased. The AA1050 − 3 wt% HEAp AMCs had the optimum mechanical properties. ItsUTS was 115 MPa and its elongation was 32.1%. The fracture mechanism of composites changed from ductile fracture toquasi-cleavage fracture with more HEAp. A theoretical model for predicting the yield strength of composites was established. The theoretical values were in good agreement with experimental results, and the average error between theoreticaland experimental values was 4.2%.