Transport of Runaway Electrons in Sawtooth Active Plasmas in the HT-7 Tokamak

Zhong Yong Chen,Wei Jin,Yang Zhang 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.7

The magnetic fluctuation level is an important parameter in lower hybrid current-drive (LHCD) plasmas because LHCD has been used to improve plasma performance extensively in the HT-7 tokamak. We investigate the transport of runaway electrons in LHCD plasmas with strong sawteeth in the HT-7 tokamak. A delay time was found to exist between the peak of the soft X-ray sawteeth and the peak of the hard X-ray flux. Based on the delay time, we obtained the transport coefficient of the runaway electrons and the averaged magnetic fluctuation level in sawtooth activity of the plasmas. We found that the diffusion coefficient of the runaway electrons was on the order of <i>D_r</i> ∼ 1 m²s⁻¹ and that the magnetic fluctuation level was on the order of <i>˜b</i> ∼ 10⁻⁶.

Observation of the Trapping of Runaway Electrons into Local Magnetic Mirrors during Slide-away Discharges in the HT-7 Tokamak

Zhong Yong Chen,Bao Nian Wan,Yuejiang Shi 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

The trapping of runaway electrons into local magnetic mirrors in a toroidal magnetic field has been observed in slide away discharges in the HT-7 tokamak. When the discharges went into the slide-away region with Parail-Pogutse instabilities, strong oscillations in the hard X-ray flux and in the electron cyclotron emission are observed. The runaway electrons are trapped into the local magnetic mirrors when they are pitch angle scattered by the anomalous Doppler resonance effect.

EMI Noise Source Reduction of Single-Ended Isolated Converters Using Secondary Resonance Technique

Chen, Zhangyong,Chen, Yong,Chen, Qiang,Jiang, Wei,Zhong, Rongqiang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

Retinoic Acid Promotes Interleukin-4 Plasmid-Dimethylsulfoxide Topical Transdermal Delivery for Treatment of Psoriasis

( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.2

Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly.(Ann Dermatol 27(2) 121∼127, 2015)

Retinoic Acid Promotes Interleukin-4 Plasmid-Dimethylsulfoxide Topical Transdermal Delivery for Treatment of Psoriasis

( Zhong Wen Chen ),( Yin Bing Zhang ),( Xaing Jun Chen ),( Xiao Liu ),( Zhen Wang ),( Xi Kun Zhou ),( Ji Qiu ),( Nan Nan Zhang ),( Xiu Teng ),( Yong Qiu Mao ),( Chang Yong Liu ),( Yu Quan Wei ),( Jion 대한피부과학회 2015 Annals of Dermatology Vol.27 No.3

Background: Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1- dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Objective: We investigated whether RA could improve anti-psoriasis efficiency using IL-4 expression plasmid pORF-mIL-4 (pIL-4) via transdermal delivery system in K14-vascular endothelial growth (K14- VEGF) factor transgenic mice. Methods: After pretreatment with RA, plasmid pIL-4 in 10% dimethylsulfoxide was applied to the ear skin by topical transdermal penetration. Hematoxylin- eosin staining and immunohistochemistry were performed with ear samples to evaluate anti-psoriasis efficiency in mice. Results: The psoriasis pathological features were relieved and psoriasis-associated factors were significantly reduced. Conclusion: Our results reveal that topical application of pIL-4 in dimethylsulfoxide by transdermal delivery with RA pretreatment can improve psoriasis significantly. (Ann Dermatol 27(2) 121∼127, 2015)

중국의 실업문제와 사회보장

진영충(Yong Zhong Chen) 한양대학교 아태지역연구센터 1999 중소연구 Vol.23 No.2

EMI Noise Source Reduction of Single-Ended Isolated Converters Using Secondary Resonance Technique

Zhang-yong Chen,Yong Chen,Qiang Chen,Wei Jiang,Rongqiang Zhong 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.

Health monitoring of carbon fiber-reinforced polymer composites in γ-radiation environment using embedded fiber Bragg grating sensors

Zhong Jing,Chen Feida,Rui Yuehao,Li Yong,Tang Xiaobin 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.8

Fiber-reinforced polymer (FRP) composites are considered suitable candidates for structural materials of spacecrafts due to their excellent properties of high strength, light weight, and corrosion resistance. An online health monitoring method for FRP composites must be applied to space structures. However, the application of existing health monitoring methods to space structures is limited due to the harsh space environment. Here, carbon fiber-reinforced polymer (CFRP) composites embedded with fiber Bragg grating (FBG) sensors were prepared to explore the feasibility of strain monitoring using embedded FBG sensors in g-radiation environment. The analysis of the influence of radiation on the strain monitoring demonstrated that the embedded FBG can be successfully applied to the health monitoring of FRP composites in radiation environment.

Prognostic Significance of CD44v6/v7 in Acute Promyelocytic Leukemia

Chen, Ping,Huang, Hui-Fang,Lu, Rong,Wu, Yong,Chen, Yuan-Zhong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

CD44v, especially splice variants containing exon v6, has been shown to be related closely to development of different tumors. High levels of CD44v6/v7 have been reported to be associated with invasiveness and metastasis of many malignancies. The objective of this study was to detect expression of CD44v6-containing variants in patients with acute promyelocytic leukemia (APL) and evaluate the potential of CD44v6/v7 for risk stratification. Reverse transcription polymerase chain reaction (RT-PCR) followed by PCR product purification, ligation into T vectors and positive clone sequencing were used to detect CD44 v6-containing variant isoforms in 23 APL patients. Real-time quantitative PCR of the CD44v6/v7 gene was performed in patients with APL and in NB4 cells that were treated with all-trans retinoic acid (ATRA) or arsenic trioxide ($As_2O_3$). Sequencing results identified four isoforms (CD44v6/v7, CD44v6/v8/v10, CD44v6/v8/v9/v10, and CD44v6/v7/v8/v9/v10) in bone marrow mononuclear cells of 23 patients with APL. The level of CD44v6/v7 in high-risk cases was significantly higher than those with low-risk. Higher levels of CD44v6/v7 were found in three patients with central nervous system relapse than in other patients inthe same risk group. Furthermore, in contrast to ATRA, only $As_2O_3$ could significantly down-regulate CD44v6/v7 expression in NB4 cells. Our data suggest that CD44v6/v7 expression may be a prognostic indicator for APL.

Antitumor Constituents from Anthriscus Sylvestris (L.) Hoffm

Chen, Hui,Jiang, He-Zhong,Li, Yong-Chao,Wei, Guo-Qing,Geng, Yun,Ma, Chao-Ying Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Bioassay-guided chemical investigation of the roots of Anthriscus sylvestris (L.) Hoffm. resulted in the isolation of nine compounds, whose structures were determined by spectroscopic methods. Compound 1 was isolated from this plant for the first time and compounds 3 and 9 were first found from this genus. Different polar fractions of A. sylvestris extract and compounds 1, 6-8 and 9 were evaluated for antitumor activities against HepG2 (human hepatocellular carcinoma), MG-63 (human osteosarcoma cells), B16 (melanoma cells) and HeLa (human cervical carcinoma cells) lines by the MTT method. The petroleum ether fraction of A. sylvestris extract exhibited excellent inhibitory activity with an $IC_{50}$ value of $18.3{\mu}g/ml$. Among the isolates from the petroleum ether fraction, compound 7 showed significant inhibition against the growth of the four tumor cells with $IC_{50}$ values ranging from $12.2-43.3{\mu}g/ml$.