Degradation of Humic Acids Using Photocatalytic Membrane Reactors

Ran, Tao,Choo, Kwang Ho,Choi, Won Yong 한국공업화학회 2002 응용화학 Vol.6 No.2

In this work, the photocatalytic degradation of humic acids (HAs) in aqueous solution was investigated using combined microfiltration/photocatalysis systems. The effects of initial HA concentration and UV irradiation intensity on HA removal were compared and assessed during batch operations. Significant UV_254 reduction occurred due to the adsorption of HA on TiO_2 before UV irradiation but the desorption of HA by photocalysis brought about an increase in UV_254 and TOC of permeate. The desorptive phenomena of HA could be attributed to the photoinduced interaction (electrical repulsion) between HA and TiO_2 Surfaces. However, further oxidative degradation of HA molecules caused the breakdown of aromatic structures in HA leading to a decrease in UV_254 and TOC of treated water. It was found that HA degradation processes did not follow the first-order reaction kinetics because of desorption phenomena.

Effects of ZrB2 Nanoparticles on the Microstructures and Tensile Properties of a Hot Extruded In Situ AA6111 Composite

Ran Tao,Yutao Zhao,Gang Chen,Xizhou Kai 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.12

Particle-reinforced aluminum matrix composites (PRAMCs) always show a low forming stability because the particles areeasily separated from the matrix, leaving voids and forming cracks. Extruded in situ PRAMCs are gradually replacing ex situPRAMCs due to the higher interface bonding between the in situ reinforcements and matrix. In this study, a hot-extrudedin situ AA6111 composite with ZrB2nanoparticles was obtained from an Al-Zr-B system. The effects of the ZrB2contenton the geometrically necessary dislocation (GND) density, grain size, grain boundaries, textures and tensile properties ofAA6111 composites were researched. The results showed that as the volume fraction of ZrB2increased, the mean GNDdislocation density increased from 1.53 × 1015m−2 to 3.23 × 1015m−2, and most dislocations were located around the ZrB2nanoparticle clusters. In addition, an increase in the ZrB2content decreased the frequency of high-angle grain boundaries(HAGBs) from 79.28 to 69.45% and increased the frequency of low-angle grain boundaries (LAGBs). ZrB2nanoparticleclusters which were located along the grain boundaries promoted continuous dynamic recrystallization (CDRX) and remarkablyrefined the grains, with the mean size decreasing from 48.2 to 1.8 μm. However, dispersed ZrB2nanoparticles inside thegrains suppressed CDRX. Tensile tests showed that the properties rose dramatically with an increasing volume fraction ofZrB2,and the optimum ultimate tensile strength (UTS), yield strength (YS) and elongation (El) of the 2 vol% ZrB2/AA6111composite were 365 MPa, 280 MPa, and 25.6%, respectively. The mechanisms for CDRX, strengthening and plasticityenhancement were determined and discussed.

광촉매/정밀여과 공정에서 휴믹산의 광분해 반응

Tao Ran,Kwang Ho Choo 대한환경공학회 2003 대한환경공학회 학술발표논문집 Vol.2003 No.12

Humic Acids Degradation and Membrane Fouling in Photocatalytic MF Systems for Drinking Water Treatment

Ran, Tao,Choo, Kwang-Ho 한국공업화학회 2003 응용화학 Vol.7 No.2

Humic acids (HA) that are one of the major organic components in natural water play an important role in water treatment because they can interact with metals, trace organics, and chlorine while generating toxic complexes and by-products. In this work, photocatalytic degradation of HA and its kinetic behavior were investigated in a photocatalytic microfiltration (MF) system, along with evaluation of membrane permeability at different fluxes. The mechanisms of adsorption and desorption of HA on TiO₂ surfaces were elucidated with adsorption isotherm tests of HA before and after photocatalysis of humic water. The kinetic parameters for humic acids, K (rate constant) and K (equilibrium adsorption coefficient) of the Langmuir-Hirnshelwood equation, were obtained based on mass balances in continuous stirred tank reactor (CSTR) operations. Regarding membrane fouling resistance. It was found that the fouling rate constant started increasing substantially when the flux increased to a level of greater than 50 L/m²-h. This indicated that the photocatalytic MF system should be operated at a flux below the critical value to prevent serious membrane fouling.

Synthesis of g-C3N4/diatomite/MnO2 composites and their enhanced photo-catalytic activity driven by visible light

Chen Ran-Ran,Ren Qi-Fang,Liu Yu-Xin,Ding Yi,Zhu Hai-Tao,Xiong Chun-Yu,Jin Zhen,오원춘 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.5

Herein, a novel visible-light-responsive g-C 3 N 4 /diatomite/MnO 2 composite was successfully fabricated through a simple redox reaction method. The structure and morphology of the sample are mainly characterized by X-ray diff raction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmis- sion electron microscopy (TEM), and ultraviolet–visible spectroscopy (UV–Vis). In this paper, the photo-catalytic activity of the sample was evaluated by degradation RhB under visible-light irradiation. The results shown that, compared with g-C 3 N 4 /diatomite composite, MnO 2 , g-C 3 N 4 , diatomite, the prepared g-C 3 N 4 /diatomite/2.5%MnO 2 composite exhibits bet- ter photo-catalytic activity and stability. At the same time, the eff ect of diff erent MnO 2 additions on the photo-catalytic activity of the composite material was further analyzed. The results indicated that the g-C 3 N 4 /MnO 2 /diatomite composites exhibit highest photo-catalytic activity when the adding amount of MnO 2 reached 2.5%. The degradation rate of the g-C 3 N 4 / diatomite/2.5%MnO 2 is 93% after recycling for three times, showing good stability and reusability. Moreover, the mechanism of catalytic performance enhancement also has been discussed.

Relationships of uPA and VEGF Expression in Esophageal Cancer and Microvascular Density with Tumorous Invasion and Metastasis

Jiang, Jian-Tao,Zhang, Lan-Fang,Zhou, Bin,Zhang, Shun-Qun,Li, Shao-Min,Zhang, Wei,Zhang, Jin,Qiao, Zhe,Kong, Ran-Ran,Ma, Yue-Feng,Chen, Sheng Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Objective: To investigate uPA and VEGF expression in esophageal cancer and relations with tumorous invasion and metastasis. Methods: Immunohistochemistry was used to detect uPA and VEGF expression in the normal epithelial tissue of esophageal mucosa and cancer tissue and detect CD34 labeled micrangium and analyze the relationships with clinical pathological features and tumor angiogenesis. Results: Positive rates for uPA and VEGF protein expression were significantly greater in esophageal cancer than normal epithelial tissue (P < 0.05), the two being linked (P <0.05). In addition, uPA and VEGF protein expression of the high microvessel density (MVD) group was significantly lower than in the low MVD group (P < 0.05), with relation to clinical pathological staging, differentiation and lymph node metastasis (P < 0.05). Conclusion: In esophageal cancer tissue, uPA and VEGF proteins are overexpressed and promote tumor angiogenesis, indicative of a poor prognosis.

Core fucosylation of maternal milk N-glycan prevents intestinal inflammation by regulating Treg/Th17 balance in infant gut microbiota

Tao Jia,Ran Yan,Pan Zhongmin,Wang Li 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.1

Background This study elucidated the regulatory roles of milk glycoprotein core fucosylation on the gut microbiota of breast-fed infants. Objectives In order to investigate the effects of core fucosylation of maternal milk N-glycan on the intestinal functions in newborn mice, Fut8 +/+ → Fut8 +/+ and Fut8 ± → Fut8 +/+ models were established. Results The results indicated that the gut microbiota diversity was altered and production of Bifidobacterium and Lactobacillus was reduced in the intestine of Fut8 ± → Fut8 +/+ mice . Furthermore, the levels of SCFAs were decreased in the gut of Fut8 ± → Fut8 +/+ infant. To further investigate the effects of core fucosylation of breast milk N-glycan on the intestinal inflammation in newborns, NEC models were established, and Fut8 +/+ off -springs with experimentally induced NEC were fed with the breast milk of Fut8 +/+ and Fut8 ± maternal mice. Our data revealed that reduced core fucosylation of breast milk N-glycan could be responsible for the intestinal inflammation in NEC off spring, as the production of pro-inflammatory cytokines including IL-1b, IL-6, IL-17A and TNF-a was significantly upregulated in Fut8 ± → Fut8 +/+ NEC group, while the levels of anti-inflammatory cytokine IL-10 were remarkably reduced. Furthermore, Treg/Th17 balance in the intestine was disturbed in Fut8 ± → Fut8 +/+ NEC newborn, suggesting the impaired immune development caused by reduced core fucosylation of breast milk. Conclusion These fi ndings indicated that core fucosylation of maternal milk N-glycan could assist the colonization of gut Lactobacillus and Bifidobacterium and regulate the Treg/Th17 balance, subsequently preventing intestinal inflammation in breast-fed newborns.

Finite-element analysis and design of aluminum alloy RHSs and SHSs with through-openings in bending

Ran Feng,Tao Yang,Zhenming Chen,Krishanu Roy,Boshan Chen,James B. P. Lim 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.3

This paper presents a finite-element analysis (FEA) of aluminum alloy rectangular hollow sections (RHSs) and square hollow sections (SHSs) with circular through-openings under three-point and four-point bending. First, a finite-element model (FEM) was developed and validated against the corresponding test results available in the literature. Next, using the validated FE models, a parametric study comprising 180 FE models was conducted. The cross-section width-to-thickness ratio (b/t) ranged from 2 to 5, the hole size ratio (d/h) ranged from 0.2 to 0.8 and the quantity of holes (n) ranged from 2 to 6, respectively. Third, results obtained from laboratory test and FEA were compared with current design strengths calculated in accordance with the North American Specifications (NAS), the modified direct strength method (DSM) and the modified Continuous strength method (CSM). The comparison shows that the modified CSM are conservative by 15% on average for aluminum alloy RHSs and SHSs with circular through-openings subject to bending. Finally, a new design equation is proposed based on the modified CSM after being validated with results obtained from laboratory test and FEA. The proposed design equation can provide accurate predictions of flexural capacities for aluminum alloy RHSs and SHSs with circular throughopenings.

Poly(vinylidene fluoride)/Plasma-Treated BaTiO3 Nanocomposites with Enhanced Electroactive Phase

Ran Ding,Lei Gong,Ming-ming Li,Shu-hua Chen,Shi-ping Zhan,Xu-dong Sun,Cheng Zhang,Tao Shao 한국고분자학회 2018 Macromolecular Research Vol.26 No.11

Functional C=O and C-O groups are successfully fixated onto the surface of a high dielectric constant material barium titanate (BaTiO3) via non-thermal plasma. The strong dipole interaction exists between these functional groups and CH2 or CF2 groups of poly(vinylidene fluoride) (PVDF), resulting in the enhancement of the electroactive γ-phase of PVDF/BaTiO3 nanocomposites on one hand; on the other hand the dispersion of BaTiO3 is enhanced in the PVDF matrix, where the smaller spherulite size and better hydrophilic property are observed in the PVDF/plasmatreated BaTiO3 nanocomposite, comparing with the untreated ones. Therefore, the PVDF/plasma-treated BaTiO3 nanoparticles exhibited higher dielectric constant and lower dielectric loss than the PVDF/BaTiO3 nanoparticles.

The New Strategy of Object-Based Directional Query

Run-tao liu,Yan-ming Wang,Zhen-guo Zhao,Guang -Yue Tian 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6

To increase directional query efficiency, based on the study of existing algorithms of directional query, new pruning rules for directional query were given, combined with the new index structure MB-tree. The rules exclude the MBRs outside the query area and output all leaf nodes in the MBRs inside the query area. Based on the orders defined in MB-tree, a new algorithm of directional query is given combining with MB-tree by using recursive method, and the new algorithm can reduce I/O cost effectively. Experiment showed that the new directional query algorithm reduces the number of visited nodes, decreases I/O cost, and improves the efficiency of directional query.