LOW TEMPERATURE SYNTHESIS OF Fe-DOPED ZnO NANOROD BUNDLES IN AQUEOUS SOLUTION

FENGXIA GENG,HUI-MING CHENG,ZHIGANG ZHAO,HONGTAO CONG,JINBO BAI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2006 NANO Vol.1 No.2

Pure and Fe-doped ZnO nanorod bundles were synthesized in aqueous solution at low temperature, in which inexpensive reagents such as Zn(NO3)2, NaOH and Fe(NO3)3 were used as precursors. The composition of the final product can be roughly tuned by the precursor ratio used. Energy dispersive X-ray spectroscopy confirms the successful incorporation of Fe element into ZnO nanorods, and X-ray diffraction reveals that ZnO nanorod bundles have a pure hexagonal wurtzite-phase structure. UV–vis spectroscopy show that the spectrum shifts to longer wavelength with increasing iron doping.

Effect of Different Blade Numbers on the Radial Force of Pump as Turbine in Transient Process

FengXia Shi,DeDong Ma,WanYong Zhao,HuTing Peng,YunSheng Liang 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.2

In order to analyze the influence of the number of blades on the radial force characteristics of pump as turbine during the variable flow rate transition process, six impellers with different number of blades are designed. On the basis of verifying the correctness of the numerical calculation method by the external characteristic experiment, the steady and unsteady numerical simulation of each scheme is carried out by ANSYS-CFX software, the radial force characteristics on impellers with different schemes are compared and analyzed. The results show that during the transition process of variable flow rate, the radial force vector and its fluctuation range on the impeller gradually decreases with the increase of the number of blades. The radial resultant force obviously increases with the increase of time in the transition to large flow rate, and obviously decreases with the increase of time in the transition to small flow rate. The dominant frequency of the radial force is equal to leaf frequency, and the pulsation amplitude of the radial force of Z9 is the minimum in both transition processes. In the transition process of variable flow rate, when the number of blades is Z9, the efficiency is the highest, the radial force on the impeller is the minimum, and the pulsation amplitude of the radial force is also the smallest, so for this pump as turbine, the value of blade number equals 9 is the optimal.

Chemical Characterization and Antitumor Activity of an Exopolysaccharide from Pholiota Squarrosa Quel. AS 5.245

Hai-zhen Zhao,Juan Wang,Fengxia Lv,Xiaomei Bie,Zhaoxin Lu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2

A water-soluble exopolysaccharide (PESP-1) was extracted and purified using DEAE Sephadex A-50 and Sephadex G-100 columns from a submerged culture broth of Pholiota squarrosa Quel. AS 5.245. PEPS-1 was investigated for antitumor activity against Heps tumors implanted in mice. An inhibition rate of 78.46% at a dosage of 100 mg/kg was observed. PEPS-1 significantly (p<0.05) increased the relative spleen/thymus indices of Heps tumor-bearing mice at a dosage of 100 mg/kg, compared with controls. Antitumor properties were probably related to stimulation of the immune response. Preliminary physicochemical analysis identified PEPS-1 as a heteropolysaccharide mainly containing D-mannose, D-glucose and D-galactose at molar ratios of 50:33:18. Small amounts of D-rhamnose and D-xylose were also detected. The average Mw of PEPS-1 was 3.26×104 Da. Structural features probably played an important role in the antitumor activity of PEPS-1.

The Production and Spatial Heterogeneity of Litterfall in the Mixed Broadleaved-Korean Pine Forest of Xiaoxing'an Mountains, China

Jin, Guangze,Zhao, Fengxia,Liu, Liang,Kim, Ji Hong Korean Society of Forest Science 2008 한국산림과학회지 Vol.97 No.2

Litterfall has been recognized an important part of the forest ecosystem production, playing a major pathway in energy flow and nutrient cycling through the ecosystem. This study was carried out to examine the quantity and components, temporal variation, and spatial heterogeneity of the litterfall in the mixed broadleaved-Korean pine forest. The data were collected from the 9ha permanent experimental plot, of which on the center area, i.e. $150m{\times}150m$, the total number of 319 circular litterfall traps with the size of $0.5m^2$ were established to collect falling litterfall. The results showed that the annual amount of litterfall was totalized 3,033.7 kg/ha, occupying broad-leaves of 39.3%, conifer-leaves of 29.5%, others of 18.5%, branches of 10.4%, and seeds of 2.3%. The peak point of the litterfall production was made at the end of September, proportionating 32.2% of total amount. The analysis of semivariogram revealed the existence of high spatial heterogeneity, calculated the scale of spatial heterogeneity ranged from 11.6 m to 29.1 m. The result of proportion (C/[Co+C]) showed that spatial heterogeneity of autocorrelation in total spatial heterogeneity were from 97.0% to 100%. The relatively heavy branches and others had significant differences in litterfall production between the areas of canopy gap and closed canopy in the 95% probability level, but the other components did not show statistical differences.

Statistical evaluation method for cylindricity deviation using local least squares cylinder

Peng Zheng,Dongliang Liu,Fengxia Zhao,Linna Zhang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.8

Accurately evaluating cylindricity deviation is the most important requirement for the quality analysis and control of cylindrical products in modern industrial manufacturing processes. The cylindricity deviation of a whole cylinder is usually evaluated with measured points from the target surface. In practice, there are many local intrinsic characteristics that can be related to defects or manufacturing errors, and some precision cylindrical workpieces such as large bearings and rollers are very sensitive to the local cylindricity quality. Hence, it is necessary to evaluate and analyze the local cylindricity variation. In previous works, few methods have focused on the deviation evaluation of local patches of the measured workpieces, and variation of local characteristics could not be directly reflected. In this paper, we propose a new statistical evaluation method for cylindricity deviation using local least squares reference cylinder, which not only evaluates the local and global cylindricity deviations, but also presents deviation change features. This paper illustrates the theoretical basis of the statistical evaluation method, provides the evaluation operation process and parameters, and finally demonstrates the accuracy and feasibility of the proposed method according to the experimental results. The proposed method can be effectively used to provide a reliable verification of the product quality and to analyze the error sources in manufacturing and inspection phases.

The Pattern of Natural Regeneration by Canopy Gap Size in the Mixed Broadleaved-Korean Pine Forest of Xiaoxing'an Mountains, China

Jin, Guangze,Tian, Yueying,Zhao, Fengxia,Kim, Ji Hong Korean Society of Forest Science 2007 한국산림과학회지 Vol.96 No.2

The forest canopy gap has been well known as a substantial process of forest cyclic regeneration and important role in stand structure, dynamics, and biodiversity of the forest ecosystem. Based on 3,600 $5m{\times}5m$ square grids in a 9ha permanent experimental plot, the study was conducted to evaluate the regeneration pattern of woody species by developmental stage {seedlings (<1 m of height), saplingI (>1 m of height, <2 cm of DBH), and saplingII (2 cm<DBH<5 cm)} for different size of forest canopy gaps ($<200m^2$), $201-400m^2$, $400-600m^2$, $601-800m^2$, and $>800m^2$) in the mixed broadleaved-Korean pine forest. The results indicated that the regenerating trees of Populus ussuriensis occurred only in the canopy gap area, considered to be a typical gap-dependent species. The regeneration of Ulmus japonica, Ulmus laciniata, and Maackia amurensis could be generally satisfied with the gap size of $201-600m^2$, Betula costata and Prunus padus with gap size of $401-800m^2$, Picea koraiensis with gap size of $201-800m^2$, Fraxinus mandshurica and Syringa reticulata var. mandshurica with smaller than $800m^2$, respectively. Acer ukurunduense and Acer tegmentosum were likely to have no problem with the gap size to make gap regeneration. Acer mono and Tilia amurensis looked more capable of regenerating in the closed canopy disregarding the upper crown condition. The regeneration of Pinus koraiensis and Abies nephrolepis had no trouble under the canopy condition in less than $800m^2$of gap size. The density of regenerating shrubs was rather high, especially under the closed canopy, considered to be associated with great amount of regeneration production in such shade tolerant species as Lonicera maackii, Corylus mandshurica, Euonymus pauciflorus, and Philadelphus schrenkii under the closed canopy. Pearson correlation coefficient was computed to compare the similarity among non-gap area and five gap size classes by developmental stages for trees and shrubs. The similarity coefficients among closed canopy and the gap size classes were mostly significantly correlated to each other with a few exceptions.

LOW TEMPERATURE SYNTHESIS OF Mg(OH)2 NANOTUBES IN AQUEOUS SOLUTIONS OF BLOCK COPOLYMER P123

HUI-MING CHENG,ZHIGANG ZHAO,FENGXIA GENG,HONGTAO CONG,JINBO BAI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2006 NANO Vol.1 No.2

A simple aqueous solution-based block-polymer-assisted method was developed for the synthesis of Mg(OH)2 nanotubes using inexpensive starting materials (MgSO4 and NaOH) with significant advance of bringing down the average outer diameter to the regime below 10 nm. The synthesized nanotubes are found to possess a relatively high specific surface area up to 64 m2/g, which may suggest their potential value for use in the catalysis field. The Barrett–Joyner–Halenda pore-size distribution plot reveals a bimodal distribution centred at 3.4 and 17.3 nm, which may be from the tunnel cavity and the aggregated pores of Mg(OH)2 nanotubes, respectively. This method can be widely used to fabricate other inorganic 1D nanostructured materials and easily realized in industrial-scale synthesis.

Preventative effects of Lactobacillus plantarum YS-3 on oxazolone-induced BALB/c colitis in mice

Feng, Xia,Zhang, Jing,Qian, Yu,Yi, Ruokun,Sun, Peng,Mu, Jianfei,Zhao, Xin,Song, Jia-Le The Korean Society for Applied Biological Chemistr 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.3

In this study, the preventative effects of Lactobacillus plantarum YS-3 (LP-YS3) on colitis were studied using an in vitro animal experiment. Oxazolone was administered to BALB/c mice to induce colitis, and the preventive effects of LP-YS3 were determined using serum- and tissue-related indexes. The mice treated with LP-YS3 showed a significant decrease (p<0.05) in disease activity index for colitis by inhibiting colon shortening and increasing colon weight/length ratio. The application of LP-YS3 resulted in a significant reduction in myeloperoxidase, nitric oxide, and malondialdehyde activities and a decrease in glutathione activity (p<0.05) in mouse colon tissues. LP-YS3 also significantly increased serum interleukin-2 and reduced interleukin-10 cytokines levels in mice (p<0.05). Reverse transcription-polymerase chain reaction and western blot assays showed that LP-YS3 application resulted in a significant increase in neuronal nitric oxide synthase, endothelial nitric oxide synthase, c-Kit, and stem cell factor expressions and a decrease in inducible nitric oxide synthase, interleukin-8, and C-X-C motif chemokine receptor 2 expressions in mouse colonic tissues (p<0.05). These findings indicate that LP-YS3 imparts preventative effects on oxazolone-induced colitis in mice.