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Weijun Zhen,Shengzhen Bian,Jinlu Sun,Xi Xi 한국고분자학회 2016 폴리머 Vol.40 No.2
Zinc oxide (ZnO) pillared organic saponite was synthesized with cetyltrimethylammonium bromide (CTAB) via a microwave hydrolysis method. Moreover, poly(lactic acid) (PLA)/ZnO pillared organic saponite nanocomposites were prepared by solution intercalation. The microstructure analysis suggested that ZnO pillared organic saponite appeared at an exfoliated or partially intercalated nanometer layer, which dispersed homogeneously in PLA matrix. The experimental results showed that ZnO pillared organic saponite improved the mechanical properties and thermal stabilities of PLA/ZnO pillared organic saponite nanocomposites. Differential scanning calorimetry (DSC) results demonstrated that the ZnO pillared organic saponite eliminated the cold crystallization process, decreased the crystal size and obviously promoted the crystallinity of PLA, which was in accordance with XRD analysis results. At the same time, the properties of UV absorbance and antibacterial properties of nano ZnO were introduced into PLA.
Impact of Synoptic Weather Types on Ground-Level Ozone Concentrations in Guangzhou, China
Wenhui Liao,Luolin Wu,Shengzhen Zhou,Xuemei Wang,Deliang Chen 한국기상학회 2021 Asia-Pacific Journal of Atmospheric Sciences Vol.57 No.2
Although precursor concentrations were reduced by emission control in Guangzhou, southern China from 2006 to 2016, ground-level O3 concentrations increased, forming potential risks to human health. This study explored the impacts of large-scale synoptic weather circulations on O3 concentration in Guangzhou, in a particular focus on high O3 pollution episodes. Twelve local weather types were clustered based on Lamb-Jenkinson weather types (LWTs). Analyses showed that LWTs strongly impacted daily O3 concentrations: A, AS, CN, and N+ weather types were likely associated with high ozone concentrations, while the ozone levels were relatively low under C, CE, CS, and S+ types. LWTs could explain 30–40% of the inter-annual variability of O3 concentration during the dry season. Numerical model simulations further demonstrated that continuous type A weather was the leading LWT correlated with high O3 concentrations, while type C weather was the predominant type correlated with low O3 concentrations. CMIP5 model results showed that occurrences of weather type A would increase by about 25% in the high emission scenario over the 2020–2069 period, which might worsen the O3 pollution in Guangzhou in the future. The increase in frequency weather type A would not be significant under the low emission scenario during the same period. Therefore, we should strictly implement the global emission reduction plan to prevent the change of weather circulation caused by climate change from aggravating ozone pollution in the future. The strong link between O3 concentrations and LWT frequencies makes the daily occurrence of LWTs a useful predictor for episodes of high O3 pollution and makes annual frequencies of LWTs good indicators of the inter-annual variability of the O3 concentration. These results are useful in efforts to predict O3 concentrations, providing a reliable weather forecast is available.
Qi Zhang,Ming Chang,Shengzhen Zhou,Weihua Chen,Xuemei Wang,Wenhui Liao,Jianing Dai,ZhiYong Wu 한국기상학회 2017 Asia-Pacific Journal of Atmospheric Sciences Vol.53 No.4
There has been a rapid growth of reactive nitrogen (Nr) deposition over the world in the past decades. The Pearl River Delta region is one of the areas with high loading of nitrogen deposition. But there are still large uncertainties in the study of dry deposition because of its complex processes of physical chemistry and vegetation physiology. At present, the forest canopy parameterization scheme used in WRF-Chem model is a single-layer “big leaf” model, and the simulation of radiation transmission and energy balance in forest canopy is not detailed and accurate. Noah-MP land surface model (Noah-MP) is based on the Noah land surface model (Noah LSM) and has multiple parametric options to simulate the energy, momentum, and material interactions of the vegetation-soil-atmosphere system. Therefore, to investigate the improvement of the simulation results of WRF-Chem on the nitrogen deposition in forest area after coupled with Noah-MP model and to reduce the influence of meteorological simulation biases on the dry deposition velocity simulation, a dry deposition single-point model coupled by Noah- MP and the WRF-Chem dry deposition module (WDDM) was used to simulate the deposition velocity (Vd). The model was driven by the micro-meteorological observation of the Dinghushan Forest Ecosystem Location Station. And a series of numerical experiments were carried out to identify the key processes influencing the calculation of dry deposition velocity, and the effects of various surface physical and plant physiological processes on dry deposition were discussed. The model captured the observed Vd well, but still underestimated the Vd. The self-defect of Wesely scheme applied by WDDM, and the inaccuracy of built-in parameters in WDDM and input data for Noah-MP (e.g. LAI) were the key factors that cause the underestimation of Vd. Therefore, future work is needed to improve model mechanisms and parameterization.
Xi Xi,Weijun Zhen,Shengzhen Bian,Wentao Wang 한국고분자학회 2015 폴리머 Vol.39 No.4
Water-soluble N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) was prepared with 2, 3-epoxypropyl trimethyl ammonium chloride grafting to the amino groups of chitosan. Then, chitosan quaternary ammonium intercalated saponite (HTCC-saponite) was synthesized with HTCC and saponite by ultrasonication intercalation. Compared with chitosan, HTCC had a good antibacterial effect. Thermoplastic poly(lactic acid) (PLA)/HTCC-saponite nanocomposites were prepared with HTCC-saponite and PLA by melt intercalation. Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H NMR) showed that HTCC was successfully synthesized by a modified method of two-step reaction. Moreover, X-ray diffraction (XRD) and scanning electron microscope (SEM) also showed that saponite was intercalated or nearly exfoliated by HTCC. It was shown the mechanical properties of PLA/HTCC-saponite nanocomposites attained the optimum when the content of HTCC-saponite was 1 phr. The studies of thermal stability, crystallization and rheological behavior of PLA/HTCC-saponite nanocomposites demonstrated that PLA/HTCC-saponite nanocomposites exhibited high performance compared with PLA.
Jianlei Jia,Qian Chen,Lin-sheng Gui,Jipeng Jin,Yongyuan Li,Qiaohong Ru,Shengzhen Hou 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.7
Objective: The present study was to investigate the association of polymorphisms in exon-9 of the bone morphogenetic protein receptor-1B (BMPR-1B) gene (C864T) with litter size in 240 Dorset, 232 Mongolian, and 124 Small Tail Han ewes. Methods: Blood samples were collected from 596 ewes and genomic DNA was extracted using the phenol: chloroform extraction method. The 304-bp amplified polymerase chain reaction product was analyzed for polymorphism by single-strand conformation polymorphism method. The genotypic frequency and allele frequency of BMPR-1B gene exon-9 were computed after sequence alignment. The χ2 independence test was used to analyze the association of genotypic frequency and litter size traits with in each ewe breed, where the phenotype was directly treated as category. Results: The results indicated two different banding patterns AA and AB for this fragment, with the most frequent genotype and allele of AA and A. Calculated Chi-square test for BMPR-1B gene exon-9 was found to be more than that of p value at the 5% level of significance, indicating that the population under study was in Hardy-Weinberg equilibrium for all ewes. The χ2 independence test analyses indicated litter size differences between genotypes was not the same for each breed. The 304-bp nucleotide sequence was subjected to BLAST analysis, and the C864T mutation significantly affected litter size in singletons, twins and multiples. The heterozygosity in exon-9 of BMPR-1B gene could increase litter size for all the studied ewes. Conclusion: Consequently, it appears that the polymorphism BMPR-1B gene exon-9 detected in this study may have potential use in marker assisted selection for litter size in Dorset, Mongolian, and Small Tail Han ewes.
Li, Jun,Cui, Yuanchao,Bi, Chenxi,Feng, Shaoqiong,Yu, Fengzhen,Yuan, En,Xu, Shengzhen,Hu, Zhe,Sun, Qi,Wei, Dengguo,Yoon, Juyoung American Chemical Society 2019 ANALYTICAL CHEMISTRY - Vol.91 No.11
<P>Hydrazine induced toxicity causes serious harm to the health of humans. The detection of N<SUB>2</SUB>H<SUB>4</SUB> in vitro and in vivo has attracted a great deal of attention, especially in the context of fluorescent probes. Although some fluorescent N<SUB>2</SUB>H<SUB>4</SUB> probes have been reported, only a few operate in purely aqueous media and, as a result, require the use of organic cosolvents which hinders their use in analysis of real samples. In addition, most of the current N<SUB>2</SUB>H<SUB>4</SUB> probes are either “off-on” or “on-off” types, in which it is difficult to eliminate interference from background fluorescence commonly occurring in in vitro and in vivo systems. Furthermore, some probes are unable to differentiate hydrazine from other organic amines. To address the above problems, we developed a novel oligo(ethylene glycol)-functionalized fluorescent probe for the detection of N<SUB>2</SUB>H<SUB>4</SUB>. The probe, which has a donor−π-acceptor (D−π-A)-type structure, is water-soluble, and it can be utilized to selectively detect N<SUB>2</SUB>H<SUB>4</SUB> in both colorimetric and ratiometric mode. Furthermore, the probe is able to differentiate hydrazine from other organic amines and can be used to detect hydrazine vapor and for imaging A549 cells and zebrafish.</P> [FIG OMISSION]</BR>