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Zhang, Zhen Xiu,Lee, Sung-Hyo,Kim, Jin-Kuk,Zhang, Shu Ling,Xin, Zhen Xiang The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.5
In order to obtain 'value added products' from polypropylene (PP)/waste ground rubber tire powder (WGRT) composites, PP/WGRT microcellular foams were prepared via supercritical carbon dioxide. The effects of blend composition and processing condition on the cell size, cell density and relative density of PP/WGRT micro-cellular composites were studied. The results indicated that the microcellular structure was dependent on blend composition and processing condition. An increased content of waste ground rubber tire powder (WGRT) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) reduced the cell size, and raised the cell density and relative density, whereas a higher saturation pressure increased the cell size, and reduced the cell density and relative density. With increasing saturation temperature, the cell size increased and the relative density decreased, whereas the cell density initially increased and then decreased.
Lili Zhang,Lanwei Zhang,Huaxi Yi,Ming Du,Yingchun Zhang,Xue Han,Zhen Feng,Jingyan Li,Yuehua Jiao,Yanhe Zhang,Chunfeng Guo 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.7
Stress-mediated bioprocess is a strategy designed to enhance biological target productivity. In this study,an attempt was made to enhance transglutaminase (TGase) production by Streptomyces mobaraensis by using different stress conditions including heat shock, alcohols and salt stress. Results showed that the effects of stress on TGase production depended on the type applied. For heat shock, TGase production (1.32 U/ml) was recorded maximum in the culture treated at 48 h post inoculation in water bath at 60 oC for 1 min. For alcohols treatment, the maximum activity of TGase (1.77 and 1.75 U/ml) was obtained when 3% methanol was added into the medium at 0 or 24 h of fermentation. However, a 3.5-fold increased production of TGase (3.8 U/ml) was observed in the medium supplemented with 0.2mol/l MgCl2 compared with the basic medium at the beginning of fermentation. In conclusion, TGase production from S. mobaraensis was improved by heat shock, methanol and salt stress treatments, MgCl2 stress was the most effective.
Linghao Zhang,Lu Zhang,Chun-Hong Zhang,Xiao-Bi Fang,Zhen-Xiao Huang,Qing -Yuan Shi,Li-Ping Wu,Peng Wu,Zhen-Zhen Wang,Zhi-Su Liao 대한이비인후과학회 2016 Clinical and Experimental Otorhinolaryngology Vol.9 No.4
Objectives. Chronic rhinosinusitis (CRS) is common disease in otorhinolaryngology and will lead to lower airway abnormality. However, the only lung function in CRS patients and associated factors have not been much studied. Methods. One hundred patients with CRS with nasal polyps (CRSwNP group), 40 patients with CRS without nasal polyps (CRSsNP group), and 100 patients without CRS were enrolled. The difference in lung function was compared. Meanwhile, CRSwNP and CRSsNP group were required to undergo a bronchial provocation or dilation test. Additionally, subjective and objective outcomes were measured by the visual analogue scale (VAS), 20-item Sino-Nasal Outcome Test (SNOT-20), Lund-Mackay score, Lund-Kennedy endoscopic score. The correlation and regression methods were used to analyze the relationship between their lung function and the above parameters. Results. The forced expiratory volume in 1 second (FEV1) and forced expiratory flow between 25% and 75% of forced vital capacity (FEF25-75) of CRSwNP group were significantly lower than other groups (P<0.05). On peak expiratory flow, there was no difference between three groups. In CRSwNP group, FEV1 was negatively correlated with peripheral blood eosinophil count (PBEC) and duration of disease (r=–0.348, P=0.013 and r=–0.344, P=0.014, respectively), FEF25-75 negatively with VAS, SNOT-20 (r=–0.490, P=0.028 and r=–0.478, P=0.033, respectively) in CRSsNP group. The incidence of positive bronchial provocation and dilation test was lower in CRSwNP group (10% and 0%, respectively), with both 0% in CRSsNP group. The multiple linear regression analysis indicated that change ratio of FEV1 before and after bronchial provocation or dilation test were correlated with PBEC in CRSwNP group (β=0.403, P=0.006). Conclusion. CRS leading to impaired maximum ventilation and small airway is associated with the existence of nasal polyp. Lung function impairments can be reflected by PBEC, duration, VAS, and SNOT-20. In CRSwNP patients, PBEC is independent predictor of FEV1 change ratio.
Zhang, Xiang-Han,Wang, Lan-Ying,Zhai, Gao-Hong,Wen, Zhen-Yi,Zhang, Zu-Xun Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.12
A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the π-π* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ±2%.
Zhang, Zhen‐,Xiu,Fan, Jun‐,ling,Pal, Kaushik,Kim, Jin Kuk,Xin, Zhen‐,Xiang Wiley Subscription Services, Inc., A Wiley Company 2011 Journal of Vinyl and Additive Technology Vol.17 No.4
<P><B>Abstract</B></P><P>Nowadays the economic recycling of waste tires has become a global challenge. The use of waste tire powder as a dispersed elastomeric phase in a polypropylene (PP) matrix offers an interesting opportunity for recycling of waste tire rubber. Compatibilized PP/(waste tire powder) composites are microcellularly processed to create a new class of materials with unique properties. Recent studies have demonstrated the feasibility of developing microcellular structures in PP/waste ground rubber tire (WGRT) composites. Microcellular PP/WGRT composites are prepared by an injection‐molding process using a chemical blowing agent. In this study, cell sizes, cell density, void fraction, and mechanical properties of the composite foams were measured, as well as the shear viscosity of the unfoamed composites. The influence of various compatibilizers and processing temperatures on cell morphology and the mechanical properties of injection‐molded PP/WGRT composites were investigated. It was seen that the addition of maleic anhydride‐grafted styrene‐ethylene‐butylene‐styrene (SEBS‐<I>g</I>‐MA) increased the shear viscosity of the composites. The void fraction and cell density of the PP/WGRT composites increased with addition of compatibilizers, whereas the average cell sizes decreased. A processing temperature range of 180–195°C gave finer microcellular structure and regular cell distribution. The SEBS‐<I>g</I>‐MA enhanced the elongation properties and acted as an effective compatibilizer in this particular system. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers</P>
A Comparative Analysis of the Safety Awareness of Korean and Chinese Construction Workers
Zhang, Zhen,안성훈 한국건축시공학회 2012 한국건축시공학회지 Vol.12 No.4
Accompanied by Chinese strong economic growth rates and development of demand for the construction industry,Chinese construction industry has already become one of the largest construction markets in the world. Unfortunately,the frequent occurrence of safety incidents on Chinese construction sites is a large obstacle for other countries construction companies seeking to enter the Chinese construction market. This study aims to analyze and compare the safety awareness of Chinese and Korean construction workers. Our research showed that the safety awareness of Korean construction workers is far higher than that of their Chinese counterparts, particularly in terms of the efficiency of safety education and the observance of safety rules. The development of a safety management plan based on these results will contribute to reducing the frequency of accidents on Chinese construction sites.