Observation of multi-channel non-local transport in J-TEXT plasmas

Shi, Yuejiang,Chen, Zhongyong,Yang, Zhoujun,Shi, Peng,Zhao, Kaijun,Diamond, Patrick H.,Kwon, JaeMin,Yan, Wei,Zhou, Hao,Pan, Xiaoming,Cheng, Zhifeng,Chen, Zhiping,Yang, SeongMoo,Zhang, Chi,Li, Da,Dong, IOP 2018 Nuclear fusion. Fusion nucléaire. &n.Illiga Vol.58 No.4

<P>In cold pulse experiments in J-TEXT, not only are rapid electron temperature increases in the core observed, but also steep rises in the inner density are found. Moreover, some evidence of acceleration of the core toroidal rotation is also observed during the non-local transport process of electron temperature. These new findings of cold pulse experiments in J-TEXT suggest that turbulence spreading is a possible mechanism for the non-local transport dynamics.</P>

Quantitative analysis using intraoperative contrast-enhanced ultrasound in adult-type diffuse gliomas with isocitrate dehydrogenase mutations: association between hemodynamics and molecular features

Xiandi Zhang,Zhifeng Shi,Yuanxin Xie,Yong Wang,Chao Shen,Zengxin Qi,Liqiong Zhang,Bojie Yang,Jinhua Yu,Hong Ding 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.4

Purpose: The relationship between contrast-enhanced ultrasound (CEUS) hemodynamics and the molecular biomarkers of adult-type diffuse gliomas, particularly isocitrate dehydrogenase (IDH), remains unclear. This study was conducted to provide a comprehensive description of the vascularization of adult-type diffuse gliomas using quantitative indicators. Additionally, it was designed to identify any variables with the potential to intraoperatively predict IDH mutation status. Methods: This prospective study enrolled patients with adult-type diffuse gliomas between November 2021 and September 2022. Intraoperative CEUS was performed, and CEUS videos were recorded for 90-second periods. Hemodynamic parameters, including the peak enhancement (PE) difference, were calculated based on the time-intensity curve of the region of interest. A differential analysis was performed on the CEUS parameters with respect to molecular biomarkers and grades. Receiver operating characteristic curves for various parameters were analyzed to evaluate the ability of those parameters to predict IDH mutation status. Results: Sixty patients with adult-type diffuse gliomas were evaluated. All hemodynamic parameters, apart from rising time, demonstrated significant differences between IDH-mutant and IDH-wildtype adult-type diffuse gliomas. The PE difference emerged as the optimal indicator for differentiating between IDH-wildtype and IDH-mutant gliomas, with an area under the curve of 0.958 (95% confidence interval, 0.406 to 0.785). Additionally, the hemodynamic parameters revealed significant differences across both grades and types of adult-type diffuse gliomas. Conclusion: Hemodynamic parameters can be used intraoperatively to effectively distinguish between IDHwildtype and IDH-mutant adult-type diffuse gliomas. Additionally, quantitative CEUS equips neurosurgeons with dynamic perfusion information for various types and grades of adult-type diffuse gliomas.

Experimental research on seismic behavior of novel composite RCS joints

Jinjie Men,Zhifeng Guo,Qingxuan Shi 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.1

Results from an experimental study on the seismic response of six composite reinforced concrete column-to-steel beam interior joints are presented. The primary variable investigated is the details in the joint. For the basic specimen, the main subassemblies of the beam and column are both continuous, and the steel beam flanges extended to the joint are partly cut off. Transverse beam, steel band plates, cove plates, X shape reinforcement bars and end plates are used in the other five specimens, respectively. After the joint steel panel yielded, two failure modes were observed during the test: local failure in Specimens 1, 2 and 4, shear failure in Specimens 3, 5 and 6. Specimens 6, 3, 5 and 4 have a better strength and deformation capacity than the other two specimens for the effectiveness of their subassemblies. For Specimens 2 and 4, though the performance of strength degradation and stiffness degradation are not as good as the other four specimens, they all have excellent energy dissipation capacity comparing to the RC joint, or the Steel Reinforced Concrete (SRC) joint. Based on the test result, some suggestions are presented for the design of composite RCS joint.

Energy-Efficient Algorithm for Assigning Verification Tasks in Cloud Storage

( Guangwei Xu ),( Zhifeng Sun ),( Cairong Yan ),( Xiujin Shi ),( Yue Li ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Mobile Cloud Computing has become a promising computing platform. It moves users` data to the centralized large data centers for users` mobile devices to conveniently access. Since the data storage service may not be fully trusted, many public verification algorithms are proposed to check the data integrity. However, these algorithms hardly consider the huge computational burden for the verifiers with resource-constrained mobile devices to execute the verification tasks. We propose an energy-efficient algorithm for assigning verification tasks (EEAVT) to optimize the energy consumption and assign the verification tasks by elastic and customizable ways. The algorithm prioritizes verification tasks according to the expected finish time of the verification, and assigns the number of checked blocks referring to devices` residual energy and available operation time. Theoretical analysis and experiment evaluation show that our algorithm not only shortens the verification finish time, but also decreases energy consumption, thus improving the efficiency and reliability of the verification.

Investigation on Chain Transfer Reaction of Benzene Sulfonyl Chloride in Styrene Radical Polymerization

Li, Cuiping,Fu, Zhifeng,Shi, Yan The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.8

The free radical polymerization of styrene was initiated with azobis(isobutyronitrile) in the presence of benzene sulfonyl chloride. Analysis of the terminal structures of the obtained polystyrene with $^1H$ NMR spectroscopy revealed the presence of a phenyl sulfonyl group at the ${\alpha}$-end and a chlorine atom at the ${\omega}$-end of each polystyrene chain. The terminal chlorine atom in the polystyrene chains was further confirmed through atom transfer radical polymerization (ATRP) of styrene and methyl acrylate using the obtained polystyrenes as macroinitiators and CuCl/2,2'-bipyridine as the catalyst system. GPC traces of the products obtained in ATRP at different reaction times were clearly shifted to higher molecular weight direction, indicating that nearly all the macroinitiator chains initiated ATRP of the second monomers. In addition, the number-average molecular weights of the polystyrenes increased directly proportional to the monomer conversions, and agreed well with the theoretical ones.

Experimental research on seismic behavior of a composite RCS frame

Jinjie Men,Yarong Zhang,Zhifeng Guo,Qingxuan Shi 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.4

To promote greater acceptance and use of composite RCS systems, a two-bay two-story frame specimen with improved composite RCS joint details was tested in the laboratory under reversed cyclic loading. The test revealed superior seismic performance with stable load versus story drift response and excellent deformation capacity for an inter-story drift ratio up to 1/25. It was found that the failure process of the frame meets the strong-column weak-beam criterion. Furthermore, cracking inter-story drift ratio and ultimate inter-story drift ratio both satisfy the limitation prescribed by the design code. Additionally, inter-story drift ratios at yielding and peak load stage provide reference data for Performance-Based Seismic Design (PBSD) approaches for composite RCS frames. An advantage over conventional reinforced concrete and steel moment frame systems is that the displacement ductility coefficient of the RCS frame system is much larger. To conclude, the test results prove that composite RCS frame systems perform satisfactorily under simulated earthquake action, which further validates the reliability of this innovative system. Based on the test result, some suggestions are presented for the design of composite RCS frame systems.

Study on Atom Transfer Radical Polymerization Initiated by p-Nitrophenyl Initiator and Synthesis of Amino End-functionalized Polymers Thereof

Tianyu Qu,Wenqian Cai,Zhifeng Fu,Yan Shi 한국고분자학회 2010 Macromolecular Research Vol.18 No.7

Atom transfer radical polymerization (ATRP) of styrene initiated by p-nitrobenzyl bromide and ATRP of methyl methacrylate (MMA) initiated by p-nitrobenzyl α-bromoisobutylate were carried out using CuBr/2,2’-bipyridine as a catalyst system. Controlled radical polymerization processes were involved in both reactions resulting in polystyrene and PMMA with nitrophenyl ends. The nitro ends of the polymers were converted to the amino-terminals through reduction in acetone with Fe and hydrochloric acid used as the reducing agent. The effect of nitrophenyl compounds on ATRP was examined and weak retardation was observed in both ATRP systems.

Loss and Efficiency Analysis of the Brushless Direct Current Motor with an Amorphous Stator Core

Lai Yifan,Hu Xiaolu,Shi Guibing,Yu Juntao,Wang Li,Gao Zhifeng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

Due to the demand for energy conservation, the loss and efficiency of a brushless direct current (BLDC) motor is investigated. In order to improve the motor efficiency, we make efforts to reduce the loss by replacing the silicon steel (SS) stator with amorphous metal (AM) stator and improving the motor design. The motor performance is analyzed by simulations and experiments, and the processing influence on loss of AM material is also considered. It shows that the performance of the AM core deteriorates due to the stress introduced during the core processing, but the utilization of AM material and the optimization design can improve the motor efficiency by 4.76%. In addition, the weight of the motor is reduced by 11.36% than that of the initial motor. This research can provide a reference for the initial design and performance evaluation of AM BLDC motors.

Contact Stiffness Determination of High-Speed Double- Locking Toolholder-Spindle Joint based on a Macro- Micro Scale Hybrid Method

Yongsheng Zhao,Jingjing Xu,Ligang Cai,Weimin Shi,Zhifeng Liu,Qiang Cheng 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.6

The stiffness of toolholder-spindle joint at high speeds plays an important role in the cutting efficiency and the machining accuracy. A double-locking toolholder (BTF type) is designed to improve the stiffness of joint. This paper presents a macro-micro scale hybrid method to determine the stiffness of double-locking toolholder-spindle joint at high speeds. In this method the finite element method and the three-dimensional fractal method are combined. It is assumed flat in macro-scale for the contact surfaces of joint. The finite element method is introduced to obtain the pressure distribution with the influence of centrifugal force at high speeds. In micro-scale, the contact surfaces are fractal featured and the three-dimensional fractal method is used to compute the stiffness based on the pressure. Experiments with BTF40-type toolholder are conducted to verify the efficiency of the proposed model in zero-speed case. The relationship between the stiffness and the technological parameters of the system can be derived based on the presented model. The upper limit of speed, the optimized range of each technological parameter are determined for obtaining the higher stiffness of joint. The results can provide theoretical basis for improving the cutting efficiency and the machining accuracy of high-speed machine tool.

Separation and Characterization of Waste Cotton/polyester Blend Fabric with Hydrothermal Method

Wensheng Hou,Chen Ling,Sheng Shi,Zhifeng Yan,Meiling Zhang,Bonan Zhang,Jinming Dai 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

In the study, a good separation efficiency of waste cotton/polyester blended fabrics (WBFs) was achieved, with dilute hydrochloric acid as the catalyst under hydrothermal conditions. The morphology and structure of the hydrothermal products including solid and liquid products were characterized by scanning electron microscopy, Fourier transform Infrared spectroscopy, X-ray diffraction, and high-performance liquid chromatography techniques and compared to the untreated polyester and cotton. The results show that the cotton fiber decomposed completely while polyester still retained its fiber characteristics after 3 h of reaction time at 150 oC and 1.5 wt% dilute hydrochloric acid. The hydrolysis of cellulose resulted in a recovery of 96.24 % of the polyester without significant change in its properties; 48.21 % of cellulose powder can be further used as the raw material of microcrystalline cellulose (MCC) and 15.57 % of glucose.