Fabrication of Photopolymer Hierarchical Micronanostructures by Coupling Electrospinning and Photolithography for SERS Substrates

Wen-Yi Zhang,Xin-Ze Xiao,Chao Lv,Jia Zhao,Gong Wang,Xuan Gu,Ran Zhang,Bin-Bin Xu,Dan-Dan Zhang,Ai-Wu Li,Yong-Lai Zhang,Hong-Bo Sun 한국고분자학회 2013 Macromolecular Research Vol.21 No.3

Reported here is the fabrication of photopolymer hierarchical micronanostructures through a combinative process of electrospinning and subsequent photolithography. Electrospun SU-8 (epoxy-based negative photoresist)nanofiber films have been patterned into gratings with periods of 100, 200, 300, and 400 μm, respectively. Deposition of a silver nanolayer on these interlaced nanofiber films would lead to the formation of various plasmonic nanostructures,and therefore, giving rise to abundant surface-enhanced Raman scattering (SERS) “hot spots”. In the detection of Rhodamine 6G (R6G), probing molecule, the resultant SERS substrates show both high sensitivity and good reproducibility. The SERS enhancement factor could reach as high as ~108, indicating high efficiency. The fabrication of patterned, highly efficient SERS substrates may hold a great promise for the integration of SERS substrates in various microdevices such as microfluidic chips.

Magnesium isoglycyrrhizinate inhibits L-type Ca2+ channels, Ca2+ transients, and contractility but not hERG K+ channels

Yue Lin,Yuanyuan Zhang,Qiongtao Song,Tao Song,Xue Han,Ying Zhang,Xuan Zhang,Xi Chu,Fenghua Zhang,Li Chu,Jianping Zhang 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.10

To explore the cardiovascular protective effectsof Magnesium isoglycyrrhizinate (MI), especially theunderlying cellular mechanisms related to L-type calciumchannels and myocardial contractility, and to examine theeffects of MI on hERG K? current expressed in HEK293cells. We used the whole-cell patch clamp technique,video-based edge detection and dual excitation fluorescencephotomultiplier systems to explore the effect of MIon L-type Ca2? currents (ICa-L) and cell contraction in ratcardiomyocytes. We also examined the rapidly activatingdelayed rectifier potassium current (IKr) expressed inHEK293 cells using a perforated patch clamp. MI inhibitedICa-L in a dose-dependent manner, with a half-maximalinhibitory concentration (IC50) of 0.22 mg/ml, and themaximal inhibitory effect was 61.10 ± 0.59%. MI at aconcentration of 0.3 mg/ml reduced cell shortening by24.12 ± 3.97% and the peak value of the Ca2? transient by36.54 ± 4.96%. MI had no significant influence on hERGK? channels expressed in HEK293 cells at all testpotentials. MI exerts protective effects on the heart via theinhibition of ICa-L and cell shortening in rat cardiomyocytes. However, MI had no significant influence on IKr;thus, MI may exert cardioprotective effects without causingdrug-induced long QT syndrome.

Study on the Influence of Distribution Lines to Parallel Inverter Systems Adopting the Droop Control Method

Zhang, Xuan,Liu, Jinjun,You, Zhiyuan,Liu, Ting The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper takes into account the influence of the different impedances of distribution lines on power distribution among inverters when the inverters are paralleled with the droop control method. The impact of distribution lines on the power distribution of inverters can be divided into two aspects. Firstly, since the distributed generators are in low voltage grids, there is resistive impedance in the distribution lines, which will cause control coupling and reduce system stability. The virtual negative resistive impedance of inverters is adopted in this paper to neutralize the resistive element of distribution lines and thus make the distribution line impedance purely inductive. Secondly, after solving the resistive impedance problem, the difference in the inductive impedance value of distribution lines due to the low density of distributed generators will cause an unequal share of reactive power. With regards to this problem, modification is put forward for the droop control strategy to share the reactive power equally. The feasibility of the design is validated by simulation and experimental results.

Formation of Magnetic Graphene Nanosheets for Rapid Enrichment and Separation of Methyl Orange from Water

Zhang, Feng-Jun,Zhang, Zhuo,Xie, Fa-Zhi,Xuan, Han,Xia, Hong-Chen,Zhu, Lei,Oh, Won-Chun The Korean Ceramic Society 2014 한국세라믹학회지 Vol.51 No.6

Magnetic-graphene nanosheets have been synthesized via a simple effective chemical precipitation method followed by heat treatment. The composite nanosheets are super paramagnetic at room temperature and can be separated by an external magnetic field. The prepared magnetic-graphene nanosheets were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and BET surface area analysis. The results demonstrated the successful attachment of iron oxide nanoparticles to graphene nanosheets. It was found that the attached nanoparticles were mainly $Fe_3O_4$. The magnetic-graphene nanosheets showed near complete methyl orange removal within 10 mintues and would be practically usable for methyl orange separation from water.

The influence of synergistic effects of hexakis (4-nitrophenoxy) cyclotriphosphazene and POE-g-MA on anti-dripping and flame retardancy of PET

Xuan Zhang,ZhiPing Mao,Qian Wu,LinPing Zhang 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

In this report, hexakis (4-nitrophenoxy) cyclotriphosphazene (HNCP) and ethylene–octene copolymer grafted-maleic anhydride (POE-g-MA) were blended with pure PET together. The fire retardant ability and thermal stability of PET/HNCP/POE-g-MA were investigated respectively. The results indicated that HNCP and POE-g-MA had a synergic effect on the dripping resistance of PET besides the enhancement in flame retardancy to a certain degree. LOI values of the polymers with both POE-g-MA and 10 wt%HNCP were higher than that of pure PET and no drips just containing 1 wt%POE-g-MA. The reason was that HNCP could be well dispersed in PET when POE-g-MA was added, forming a more effective char layer and preventing dripping of polymers. Indeed, the morphology of charred residue of PET/HNCP/POE-g-MA showed that a porous protective layer with a dense surface was formed. The thermogravimetric analysis revealed that addition of HNCP improved the thermal stability and the yield of char residue of the PET/POE-g-MA systems. Based on a series of experiment results, the synergistic effect of HNCP and POE-g-MA on the anti-dripping of PET was also discussed. In the PET/HNCP/POE-g-MA system, POE-g-MA played a role of compatibilizer. The improved compatibility and dispersion provided the composite with the ideal flame retardancy, thermal stability and anti-dripping property.

Erratum to: The treatment effect of novel hGHRH homodimer to male infertility hamster

Zhang, Xu-Dong,Guo, Xiao-Yuan,Tang, Jing-Xuan,Yue, Lin-Na,Zhang, Juan-Hui,Liu, Tao,Dong, Yu-Xia,Tang, Song-Shan The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.1

Physiological Races of Phytophthora infestans in Korea

Xuan-Zhe Zhang,Byung-Sup Kim 한국식물병리학회 2007 Plant Pathology Journal Vol.23 No.3

A total of the 261 Phytophthora infestans isolates collected from 2003 to 2005 in Korea were investigated for their physiological race composition. Among the isolates, we detected 18 physiological races and the dominant races were R0.1.3.5.6.10.11 and R0.1.3.5.6.7. 10.11 with frequencies of 18.4% and 11.4%, respectively. All of the P. infestans races carried multiple virulence genes and showed virulence to the potato resistance genes R1, R3, R5, R6, R7, R10 and R11, but not to R8 and R9. Therefore, it is likely that the physiological races of P. infestans were diverse in Korea.

Virtual negatively resistive output impedance for power sharing among paralleled inverters in microgrid

Xuan Zhang,Jinjun Liu,Ting Liu 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In this paper, a new control method for paralleled inverters in microgrid is presented. The strategy of power sharing among inverters in microgrid can be divided into control with and without communication. When there is no communication among inverters, droop control is used to share power. But droop control is effective only when the transmission line is approximately pure inductive. Microgrid is in the distribution network in power system, so the resistive component in transmission line is very high. Under this condition, there is severe coupling in droop control and power sharing mechanism is invalid. In this paper, by making use of virtual impedance, the equivalent output impedance of inverter becomes negatively resistive, while its amplitude equals to the value of resistive component in transmission line, so the resistive component in transmission line will be neutralized. So the circuit can be viewed as inverter supplying power through pure inductive transmission line. Therefore, the coupling in droop control can be removed and power sharing mechanism is effective. The analysis of the proposed method and design procedure are provided. Simulation results validate the proposed control strategy.

Changes in the Sensitivity to Metalaxyl, Dimethomorph and Ethaboxam of Phytophthora infestans in Korea

Xuan-Zhe Zhang,김점순,전정욱,김병섭,Kyoung-Yul Ryu 한국식물병리학회 2005 Plant Pathology Journal Vol.21 No.1

Changes of control efficacy of chemical to potato late blight caused by Phytophthora infestans in potato fields from 2001 to 2004 were examined. Control efficacy of metalaxyl was suddenly decreased from 100% in 2002 to 50% in 2004 and that of dimethomorph also was similar to those of metalaxyl. However, the control efficacy of ethaboxam no great change. Both A1 and A2 mating type isolates were isolated from 2001 to 2004 in several areas in Korea. The majority of the P. infestans isolates were A1 mating type. Total 939 isolates of P.infestans obtained from several areas in Korea from 2001 to 2004 were examined for changes of sensitivity to metalaxyl. Frequencies of metalaxyl resistance isolates were gradually increased from 17% in 2001 to 84.2% in 2004, but isolation frequencies of metalaxyl sensitive and intermediate resistant isolate were decreased.Cause of decreasing control efficacy of metalaxyl was thought by increase of resistance isolates in A1 mating type population according to increasing metalaxyl use. Most isolates were grown at 0.5 µg/ml of dimethomorph and isolates grown at 1 µg/ml of dimethomorph were approximately 10.2-22.9%. However, no isolate was able to grow at 5.0 µg/ml. Based on these results,minimum inhibitory concentrations (MIC) of dimethomorph to P. infestans were determined to be 0.5-1.0 µg/ml. Our results indicated that the reason decreasing control efficacy of dimethomorph was not caused by occurrence of resistant isolates. About 5% and 12.1% isolates among the total isolates collected in 2003 and 2004 were grown on V-8 juice rye agar containing 1.0 µg/ml ethaboxam. The 2.1 and 25.4% isolates had MICs of 0.2-0.4 µg/ml, and MIC values of 87.9% and 74.3% isolates were less than 0.2 µg/ml concentrations of ethaboxam. Therefore, resistance development by P. infestans to ethaboxam is not likely to occur in the natural condition

Gender Differences in User-generated Travel Photographs on Social Media

Xuan Zhang,HeeJeong Yun 한국무역연구원 2016 무역연구 Vol.12 No.1

This study examines the gender differences in user-generated travel photographs posted onsocial networking services. Using 515 travel photographs—285 generated by females and 230generated by males—from China’s Sina Weibo website, the study analyzes the genderdifferences in the photographs and the geographical distribution differences using ageographical information system (GIS). The results show that there are statistical genderdifferences in terms of four variables: type of landscape, regional attribute, photographicdistance, and number of people in the photograph. In particular, photographs generated bywomen tend to show natural landscapes, while photographs generated by males tend to showcultural landscapes. Additional researches are needed to determine the reason for such genderdifferences, as are advanced differential studies that would consider variables other thangender.