Photosensitive Al2O3 slurry with high solid content and low viscosity

Zhang Xu,Zhang Jingde,Tian Yuhang,Xiao Shikang,Li Jianzhang,Han Guifang 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

Slurries with high solid content and low viscosity are highly necessary to lower the sintering shrinkage and avoid possible defects for ceramic components fabricated by vat photopolymerization technique. However, the viscosity of slurry dramati- cally arises with the increase of solid content, which severely affects the printing process and the quality of preformance. To solve this issue, a novel combined strategy of powder surface modification and selection of dispersant was proposed to significantly increase the solid load without too much increase in viscosity. The surface of Al 2O3 particles was modified by Silane A174 to improve its wettability with resins, and then the use of KOS 110 formed steric hindrance between particles achieving good dispersion. The synergistic effect of the modifier and dispersant was realized. Al 2O3 slurry with a high solid loading up to 65 vol% and low viscosity of 20.0 Pa·s at 30  s −1 was prepared for stereolithography-based DLP 3D printing, which had among the highest performance in photosensitive Al 2O3 slurries.

Effect of La(NO3)3 and Ce(NO3)3 on shoot induction and seedling growth of in vitro cultured anoectochilus roxburghii

Yingya Xu,Guifang Zhang,Yan Wang,Ge Guo 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

Anoectochilus roxburghii, a highly valuable medicinal plant species, is threatened in its native habitat. To ensure the sustainability of this useful resource, we studied the effect of La(NO3)3 and Ce(NO3)3 on plant tissue culturepropagated A. roxburghii. Apical buds, mid-stem segments, and basal rhizome segments were taken from aseptic seedlings of A. roxburghii and cultured in vitro on half-strength Murashige-Skoog medium containing different concentrations (up to 5.0 mg/L) of La(NO3)3 or Ce(NO3)3. After 100 d of culturing, average heights of plantlets derived from apical buds were 6.0 cm with 5.0 mg/L La(NO3)3 and 6.2 cm with 2.0 mg/L Ce(NO3)3, which respectively increased by 28.0% and 32.0% as compared with that in the non-treated control group. The optimum concentration for shoot induction from mid-stem segments was 1.0 mg/L Ce(NO3)3 which had a better proliferation times of 1.5-fold and an average length of 3.0 cm compared with 1.0-fold and 2.2 cm in the control group. Optimum growth from basal rhizome segments was achieved on media supplemented with 3.0 mg/L Ce(NO3)3, which provided a better proliferation times of 5.1-fold and an average shoot length of 4.5 cm compared with corresponding control values of 2.0-fold and 3.5 cm. Our results showed that La(NO3)3 and Ce(NO3)3 can accelerate A. roxburghii regeneration, which was probably due to the effect on chlorophyll contents, enzymes activity (superoxide dismutase, catalase and peroxidase) and malonldialedhyde contents caused by the addition of La(NO3)3 or Ce(NO3)3.

Putative multiple reaction monitoring strategy for the comparative pharmacokinetics of postoral administration Renshen-Yuanzhi compatibility through liquid chromatography-tandem mass spectrometry

Yufei Sun,Guifang Feng,Yan Zheng,Shu Liu,Yan Zhang,Zifeng Pi,Fengrui Song,Zhiqiang Liu 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Exploring the pharmacokinetic (PK) changes of various active components of single herbs and their combinations is necessary to elucidate the compatibility mechanism. However, the lack of chemical standards and low concentrations of multiple active ingredients in the biological matrix restrict PK studies. Methods: A putative multiple reaction monitoring strategy based on liquid chromatography coupled with mass spectrometry (LC-MS) was developed to extend the PK scopes of quantification without resorting to the use of chemical standards. First, the compounds studied, including components with available reference standard (ARS) and components lacking reference standard (LRS), were preclassified to several groups according to their chemical structures. Herb decoctions were then subjected to ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis with appropriate collision energy (CE) in MS² mode. Finally, multiple reaction monitoring transitions transformed from MS² of ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were used for ultrahigh-performance liquid chromatography coupled with triple quadrupole mass spectrometry to obtain the mass responses of LRS components. LRS components quantification was further performed by developing an assistive group-dependent semiquantitative method. Results: The developed method was exemplified by the comparative PK process of single herbs Radix Ginseng (RG), Radix Polygala (RP), and their combinations (RG-RP). Significant changes in PK parameters were observed before and after combination. Conclusion: Results indicated that Traditional Chinese Medicine combinations can produce synergistic effects and diminish possible toxic effects, thereby reflecting the advantages of compatibility. The proposed strategy can solve the quantitative problem of LRS and extend the scopes of PK studies.

Putative multiple reaction monitoring strategy for the comparative pharmacokinetics of postoral administration RensheneYuanzhi compatibility through liquid chromatographyetandem mass spectrometry

Yufei Sun,Guifang Feng,Yan Zheng,Shu Liu,Yan Zhang,Zifeng Pi,Fengrui Song,Zhiqiang Liu 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Exploring the pharmacokinetic (PK) changes of various active components of single herbsand their combinations is necessary to elucidate the compatibility mechanism. However, the lack ofchemical standards and low concentrations of multiple active ingredients in the biological matrix restrictPK studies. Methods: A putative multiple reaction monitoring strategy based on liquid chromatography coupledwith mass spectrometry (LCeMS) was developed to extend the PK scopes of quantification withoutresorting to the use of chemical standards. First, the compounds studied, including components withavailable reference standard (ARS) and components lacking reference standard (LRS), were preclassifiedto several groups according to their chemical structures. Herb decoctions were then subjected toultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometryanalysis with appropriate collision energy (CE) in MS2 mode. Finally, multiple reaction monitoringtransitions transformed from MS2 of ultrahigh-performance liquid chromatography coupled withquadrupole time-of-flight mass spectrometry were used for ultrahigh-performance liquid chromatographycoupled with triple quadrupole mass spectrometry to obtain the mass responses of LRS components. LRS components quantification was further performed by developing an assistive groupdependentsemiquantitative method. Results: The developed method was exemplified by the comparative PK process of single herbs RadixGinseng (RG), Radix Polygala (RP), and their combinations (RGeRP). Significant changes in PK parameterswere observed before and after combination. Conclusion: Results indicated that Traditional Chinese Medicine combinations can produce synergisticeffects and diminish possible toxic effects, thereby reflecting the advantages of compatibility. The proposedstrategy can solve the quantitative problem of LRS and extend the scopes of PK studies.

Entropic Image Thresholding Segmentation Based on Gabor Histogram

( Sanli Yi ),( Guifang Zhang ),( Jianfeng He ),( Lirong Tong ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.4

Image thresholding techniques introducing spatial information are widely used image segmentation. Some methods are used to calculate the optimal threshold by building a specific histogram with different parameters, such as gray value of pixel, average gray value and gradient-magnitude, etc. However, these methods still have some limitations. In this paper, an entropic thresholding method based on Gabor histogram (a new 2D histogram constructed by using Gabor filter) is applied to image segmentation, which can distinguish foreground/background, edge and noise of image effectively. Comparing with some methods, including 2D-KSW, GLSC-KSW, 2D-D-KSW and GLGM-KSW, the proposed method, tested on 10 realistic images for segmentation, presents a higher effectiveness and robustness.

Amperometric Determination of Nitrite at Poly(Methylene Blue)-Modified Glassy Carbon Electrode

Xu, Guang-Ri,Xu, Guifang,Xu, Ming-Lu,Zhang, Zhengqing,Tian, Yuan,Choi, Han-Nim,Lee, Won-Yong Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range $2.0{\times}10^{-6}$ to $5.0{\times}10^{-4}$ M with the detection limit of $2.0{\times}10^{-6}$ M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Cl^-$, $HPO_4^{2-}$ and $H_2PO_4^- $. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.

Putative multiple reaction monitoring strategy for the comparative pharmacokinetics of postoral administration Renshen-Yuanzhi compatibility through liquid chromatography-tandem mass spectrometry

Sun, Yufei,Feng, Guifang,Zheng, Yan,Liu, Shu,Zhang, Yan,Pi, Zifeng,Song, Fengrui,Liu, Zhiqiang The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.1

Background: Exploring the pharmacokinetic (PK) changes of various active components of single herbs and their combinations is necessary to elucidate the compatibility mechanism. However, the lack of chemical standards and low concentrations of multiple active ingredients in the biological matrix restrict PK studies. Methods: A putative multiple reaction monitoring strategy based on liquid chromatography coupled with mass spectrometry (LC-MS) was developed to extend the PK scopes of quantification without resorting to the use of chemical standards. First, the compounds studied, including components with available reference standard (ARS) and components lacking reference standard (LRS), were preclassified to several groups according to their chemical structures. Herb decoctions were then subjected to ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis with appropriate collision energy (CE) in MS² mode. Finally, multiple reaction monitoring transitions transformed from MS² of ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were used for ultrahigh-performance liquid chromatography coupled with triple quadrupole mass spectrometry to obtain the mass responses of LRS components. LRS components quantification was further performed by developing an assistive group-dependent semiquantitative method. Results: The developed method was exemplified by the comparative PK process of single herbs Radix Ginseng (RG), Radix Polygala (RP), and their combinations (RG-RP). Significant changes in PK parameters were observed before and after combination. Conclusion: Results indicated that Traditional Chinese Medicine combinations can produce synergistic effects and diminish possible toxic effects, thereby reflecting the advantages of compatibility. The proposed strategy can solve the quantitative problem of LRS and extend the scopes of PK studies.

Amperometric Determination of Nitrite at Poly(Methylene Blue)-Modified Glassy Carbon Electrode

Guang-Ri Xu,Guifang Xu,Ming-Lu Xu,Zhengqing Zhang,Yuan Tian,최한님,이원용 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.2

Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range 2.0 × 10−6 to 5.0 × 10−4 M with the detection limit of 2.0 × 10−6 M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as Na+, K+,Ca2+, Cl−, HPO42− and H2PO4−. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.

Solution processable small molecules for organic light-emitting diodes

Duan, Lian,Hou, Liudong,Lee, Tae-Woo,Qiao, Juan,Zhang, Deqiang,Dong, Guifang,Wang, Liduo,Qiu, Yong Royal Society of Chemistry 2010 Journal of materials chemistry Vol.20 No.31

<P>Organic light-emitting diodes (OLEDs) based on vacuum deposited small molecules have undergone significant progress since the first efficient double-layered OLEDs were reported in 1987 by Tang and Van Slyke. Recently, solution processed small molecular OLEDs are also drawing more and more research attention, as such a technology combines advantages of the facile synthesis of small molecules and the low-cost solution process like polymers. The performance of OLEDs made by solution process is gradually catching up with their vacuum deposited counterparts. This feature article will review the device structures adopted to achieve high performance solution processed OLEDs, the development of solution processable small molecules, and the comparisons of the different nature of the films and devices fabricated by solution-process or by vacuum deposition. Finally, the prospects and remaining problems will be discussed.</P> <P>Graphic Abstract</P><P>Recent developments, prospects and remaining problems of organic light-emitting diodes based on solution processable small molecules are reviewed, with comparisons of the films and devices by solution-process or vacuum deposition. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b926348a'> </P>