Impact of Defects in Steel-Concrete Interface on the Corrosion-Induced Cracking Propagation of the Reinforced Concrete

Wenjun Zhu,Chengyue Yang,Zhongxu Yu,Junhua Xiao,Yude Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.6

This paper presents the corrosion-induced cracking performance of reinforced concrete in a chloride condition. The meso-scale structures of concrete specimens were studied according to the X-ray micro-computed tomography test, including the corrosion propagation, the accumulation and transportation of corrosion products, the defects and cracking behaviors of concrete cover. The experimental results show that the defects could provide a reasonable space for the accommodation of corrosion products, which could significantly increase the corrosion process and postpone the cracking performance. The propagation of the cracking path initiating from the corrosion area of the reinforcement to the concrete cover was also captured based on the experimental images, which can make contribution to the recognition of corrosion-induced cracking behavior of the concrete cover.

Effect of corrosion pattern on the ductility of tensile reinforcement extracted from a 26-year-old corroded beam

Zhu, Wenjun,Francois, Raoul Techno-Press 2013 Advances in concrete construction Vol.1 No.2

Tension tests were carried out to investigate the effect of the corrosion pattern on the ductility of tension bars extracted from a 26-year-old corroded reinforced concrete beam. The tensile behavior of corroded bars with different corrosion patterns was examined carefully, as were two non-corroded bars extracted from a 26-year-old control beam. The results show that corrosion leads to an increase in the ratio of the ultimate strength over the yield strength, but reduces the ultimate strain at maximum force of the reinforcement. Both the corrosion pattern and the corrosion intensity play an important role in the ductile properties. The asymmetrical distribution of the corrosion around the surface is a decisive factor, which can influence the ultimate strain at maximum force more seriously.

Core–shell ZIF-67(Co) wrapped CuO as high efficient peroxymonosulfate catalyst for the degradation of methylene blue

Zhu Wenjun,Zuo Xiaohua,Deng Xiangyi,Zhang Xinhao,Yao Chuang,Wang Xiaobo 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Core–shell ZIFs wrapped CuO hybrid materials (CuO@ZIF-67(Co)) were designed, synthesized, characterized, and employed as peroxymonosulfate (PMS) activators to degrade methylene blue (MB). It demonstrated outstanding catalytic activity on account of the unique structure and the synergistic effect between CuO cores and ZIF-67(Co) shells, resulting in complete degradation of MB (10 mg/L) in 1 min. Reactive oxygen species (ROSs) research showed that both SO4− and OH were responsible for the removal of MB. The synergistic activation mechanisms in the CuO@ZIF-67(Co)/PMS system were investigated, which mainly involved the effective electron transfer of CuO and ZIF-67(Co) for accelerating the cycle of CuII/CuI and CoIII/CoII. This study broadens the application of MOF-derived materials for wastewater treatment.

Laccase-Mediated In Situ Oxidation of Dopamine for Dyeing of Human Hair

Weini Jia,Shirong Li,Zhengxin Luo,Hainan Yu,Wenjun Zhu,Wenjun Zhu,Qing-hui Mao,Xiaoli Zhang,Zhi-jie Liang,Aixue Dong 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1

Due to the damage of scalp because of chemical dyes, increasing attention had been paid to the ecological dyeingof human hair. To address the need for ecological restoration and dyeing of human hair, herein, a novel approach has beenproposed via laccase-mediated in situ oxidation of dihydroxy phenylalanine (dopamine). As laccase can catalyze dopamineoxidation and then polymerization to produce strongly colored polymers, different biological coloration processes of humanhair based on this process were investigated: (i) Human hair was treated with laccase alone; (ii) The absorption of human hairwith dopamine, followed by further catalysis of air; (iii) The absorption of human hair with dopamine, followed by furthercatalysis of laccase; (iv) Simultaneous laccase-mediated polymerization and dyeing of human hair; and (v) Polymerization ofDopamine with laccase and then dyeing human hair. The surface properties of dyed hair were evaluated in terms of ultraviolet(UV)-protection, color fastness, Fourier transforming infrared spectrum (FT-IR), optical microscope, and scanning electronmicroscopy (SEM). The results show that best hair dyeing effect was achieved via simultaneous laccase-mediatedpolymerization and dyeing. The dyed hair obtained K/S values of 28, light fastness of level 5, and UPF of 100+. The opticalmicroscope and SEM observations show that the surface of colored hair fibers was covered with thin burrs, which can beattributed to polydopamine attached with physical adhesive force and covalent reaction. FT-IR analysis shows that functionalgroups were present on the surface of the dyed hair which can be considered as introduction of hydroxyl radical groups. Thisbiological stain technique may be widely used in dyeing of hair with black color.

Sizing Performance Improvement of Cotton Yarns Pretreated with UV Irradiation

Wenjun Yan,Bo Zhu,Weidong Gao 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

UV irradiation technology has the advantages of ease operation, affordable, and clean production. This paperfocused on the wettability improvement of cotton yarns by UV irradiation, and proposed UV irradiation pretreatment methodto improve the sizing performance of cotton yarns. The surface elemental composition and molecular structure before andafter UV irradiation were characterized. The effects of UV irradiation pretreatment intensity and time on apparent properties,weight, wettability and mechanical properties of raw cotton yarns were analyzed. The impact of UV irradiation pretreatmentprocess on sized yarns performance including mechanical properties, hairiness, yarn evenness and size pick-up were studied. Then, the mechanical properties of the sized yarns after alkali desizing were investigated. The results showed that UVirradiation pretreatment can introduce oxygen-containing polar groups on the cotton yarns. Meanwhile, it had a certaindegradation effect on the surface of the cotton yarns, which resulted in wax removed, roughness improvement and exposureof cellulose. The above reasons jointly caused the wettability improvement of raw cotton yarns after UV irradiation. Compared with the unpretreated sized ones, the breaking strength, breaking elongation and abrasion resistance of the UVirradiation pretreated sized yarns was greatly enhanced by 20.13 %, 20.54 % and 103.49 % respectively. The hairiness wasreduced by 88.23 %, and the yarn evenness was improved by 6.74 %. It presented the optimized sizing performance when theyarns were pretreated at UV irradiation intensity of 142.5 mW/cm2 for 120 min. After desizing, the decline amplitude waslittle between unpretreated and UV irradiation pretreated yarns.

Identification of pathways and genes associated with cerebral palsy

Qingwen Zhu,Yufei Ni,Jing Wang,Honggang Yin,Qin Zhang,Lingli Zhang,Wenjun Bian,Bo Liang,Lingyin Kong,Liming Xuan,Naru Lu 한국유전학회 2018 Genes & Genomics Vol.40 No.12

Cerebral palsy (CP) is a non-progressive neurological disease, of which susceptibility is linked to genetic and environmental risk factors. More and more studies have shown that CP might be caused by multiple genetic factors, similar to other neurodevelopmental disorders. Due to the high genetic heterogeneity of CP, we focused on investigating related molecular pathways. Ten children with CP were collected for whole-exome sequencing by next-generation sequencing (NGS) technology. Customized processes were used to identify potential pathogenic pathways and variants. Three pathways (axon guidance, transmission across chemical synapses, protein–protein interactions at synapses) with twenty-three genes were identified to be highly correlated with CP. This study showed that the three pathways associated with CP might be the molecular mechanism of pathogenesis. These findings could provide useful clues for developing pathway-based pharmacotherapies. Further studies are required to confirm potential roles for these pathways in the pathogenesis of CP.

Carotid stiffening predicts cardiovascular risk stratification in mid-life: non-invasive quantification with ultrafast ultrasound imaging

Zhengqiu Zhu,Lingshan Chen,Wenjun Liu,Yiyun Wu,Chong Zou,Xinyi Zhang,Shanshan He,Yinping Wang,Bixiao Shen,Xuehui Ma,Hui Gao,Yun Luan,Hui Huang 대한초음파의학회 2022 ULTRASONOGRAPHY Vol.41 No.3

Purpose: The present study investigated the association between Systematic COronary Risk Evaluation (SCORE)-estimated cardiovascular risk and carotid stiffening in a middle-aged population using ultrafast pulse wave velocity (ufPWV).Methods: This study enrolled 683 participants without known cardiovascular disease or diabetes mellitus who underwent ufPWV measurements. Clinical interviews, physical examinations, laboratory findings, carotid intima-media thickness (cIMT), pulse wave velocity (PWV) at the beginning of systole (PWV-BS), and PWV at the end of systole (PWV-ES) were assessed. Each participant underwent an assessment of SCORE risk based on major cardiovascular risk factors (CVRFs), including age, sex, smoking, systolic blood pressure (SBP), and total cholesterol (TC). Crude and adjusted odds ratios (ORs) with 95% confidence intervals and ordinal logistic regression were used. Overall CVRFs were adjusted to assess ORs.Results: cIMT and carotid stiffening in PWV-BS and PWV-ES were significantly different between sex subgroups (all P<0.05), but only PWV-ES increased gradually in age and SCORE-estimated risk subgroups (all P<0.05). Compared with cIMT (r=0.388, P<0.001) and PWV-BS (r=0.159, P<0.001), PWV-ES was more strongly correlated with SCORE categories (r=0.405, P<0.001). Higher PWV-ES values were associated with SCORE categories independently of sex, SBP, TC, and smoking in moderate-risk and high-risk subgroups (OR, 1.63; P<0.001 and OR, 2.12; P=0.024, respectively), but were not independent of age in all risk subgroups (all P>0.05).Conclusion: Carotid stiffening quantified by ufPWV is linked to SCORE categories, and elevated PWV-ES may aid in cardiovascular risk stratification.

Influence of thermophilic microorganism on non-volatile metabolites during high-temperature pile-fermentation of Chinese dark tea based on metabolomic analysis

Wen Zhu,Wenfeng Wang,Wencan Xu,Shuang Wu,Wenjun Chen,Youyi Huang,Shengpeng Wang 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.7

Pile-fermentation is a critical procedure for producing Chinese dark tea, during which thermophilic microorganisms would play an irreplaceable role. However, there have been little researches on the influences of thermophilic microorganism pile-fermentation (TMPF) in high-temperature of Chinese dark tea. Thus, we conducted high-performance liquid chromatography and nontargeted metabolomic to analyze the non-volatile metabolites of TMPF. Our results discovered that the amounts of ( −)-epigallocatechin gallate, ( −)-epigallocatechin, ( −)-epicatechin gallate, and ( −)-epicatechin were decreased significantly (p < 0.05) after TMPF. By using nontargeted metabolomic analysis, a total of 1733 ion features were detected. KEGG pathway enrichment analysis showed that TMPF had a significant impact on caffeine metabolism. Also, theophylline, 3-methylxanthine, and 1,3,7-trimethyluric acid were increased significantly after TMPF, which suggested that demethylation and oxidation reaction might be the main pathways of caffeine metabolism. This study provides a better understanding of the mechanism of TMPF during high-temperature for Chinese dark tea and lays a foundation for further research.

Quantifying carotid stiffness in a pre-hypertensive population with ultrafast ultrasound imaging

Xuehui Ma,Zhengqiu Zhu,Yinping Wang,Bixiao Shen,Xuezhong Jiang,Wenjun Liu,Yiyun Wu,Chong Zou,Yun Luan,Hui Gao,Hui Huang 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.1

Purpose: The aim of this study was to assess carotid stiffening in a pre-hypertensive (PHT) population using ultrafast pulse wave velocity (ufPWV). Methods: This study retrospectively enrolled 626 individuals who underwent clinical interviews, serum tests, and assessments of the systolic blood pressure (SBP), diastolic blood pressure (DBP), carotid intima-media thickness (cIMT), pulse wave velocity-beginning of systole (PWV-BS), and pulse wave velocity-end of systole (PWV-ES) between January 2017 and December 2021. The patients were divided into three groups according to their blood pressure (BP)—normal BP (NBP): SBP <130 mmHg and DBP <80 mmHg (n=215); PHT: 130 mmHg≤SBP<140 mmHg and/or 80 mmHg≤DBP<90 mmHg (n=119); hypertensive (HT): SBP ≥140 mmHg and/or DBP ≥90 mmHg (n=292). Correlation analyses and comparisons were performed among the groups and in the cIMT subgroups (cIMT ≥0.050 cm and <0.050 cm). Results: cIMT and PWV-ES significantly differed among the BP groups (P<0.05). The BP groups had similar PWV-BS when cIMT <0.050 cm or cIMT ≥0.050 cm (all P>0.05). However, the NBP group had a notably lower PWV-ES than the PHT (P<0.001 and P=0.024) and HT (all P<0.001) groups in both cIMT categories, while the PWV-ES in the PHT group were not significantly lower than in the HT group (all P>0.05). Conclusion: Carotid morphological and biomechanical properties in the PHT group differed from those in the NBP group. ufPWV could be used for an early evaluation of carotid stiffening linked to pre-hypertension.

Eu³⁺→Eu²⁺ unusual reduction and bond energy in MAlSi₂O₆:Eu (M = Li, Na, K, Rb, Cs)

Pan, Yu,Wang, Wenjun,Zhu, Yuhan,Xu, Haibing,Noh, Hyeon Mi,Jeong, Jung Hyun,Liu, Xiaoguang,Li, Ling Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.7

<P><B>Abstract</B></P> <P>Eu-doped MAlSi<SUB>2</SUB>O<SUB>6</SUB> (M = Li, Na, K, Rb, Cs) phosphors were synthesized by solid-state reaction in air. The crystal structure and optical properties of the phosphors were investigated by X-ray powder diffraction and photoluminescence. Their emission spectra are composed of some broad bands coming from the 5d-4f transition of Eu<SUP>2+</SUP> and some sharp emission peaks coming from the f-f transitions of Eu<SUP>3+</SUP>. The co-existence of Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> cations is detected in MAlSi<SUB>2</SUB>O<SUB>6</SUB>:2%Eu, which shows that the unusual Eu<SUP>3+</SUP>→Eu<SUP>2+</SUP> reduction process occurs in MAlSi<SUB>2</SUB>O<SUB>6</SUB>. The preferential occupancy of Eu<SUP>3+</SUP> or Eu<SUP>2+</SUP> in MAlSi<SUB>2</SUB>O<SUB>6</SUB> can be calculated to be M<SUP>+</SUP> sites by the bond-energy method. The deviation of the Eu<SUP>3+</SUP>–O<SUP>2-</SUP> bond energy is closed to that of the Eu<SUP>2+</SUP>–O<SUP>2-</SUP> bond energy, which means that Eu<SUP>3+</SUP> and Eu<SUP>2+</SUP> can coexist in air. The abnormal reduction of Eu<SUP>3+</SUP> to Eu<SUP>2+</SUP> can be explained by charge compensation model. The doped Eu<SUP>3+</SUP> was induced to M<SUP>+</SUP> and the vacancy (<I>V</I> <SUB> <I>M</I> </SUB>) may be formed. The vacancy(<I>V</I> <SUB> <I>M</I> </SUB>) acted as a donor of electrons, and the Eu M ∙ ∙ defect acted as an acceptor of electrons. The theoretical result is consistent with the experimental phenomenon.</P>