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Hu, Zeshan,Shao, Minghao,Li, Huayang,Cai, Qiang,Zhong, Chenghua,Xianming, Zhang,Deng, Yulin The Korean Society for Composite Materials 2009 Advanced composite materials Vol.18 No.4
PCC (precipitated calcium carbonate) and ground calcium carbonate have been widely used in alkaline papermaking. Unfortunately, although increasing filler level in papers can improve the paper properties such as brightness, opacity, stiffness gloss, smoothness, porosity, and printability, as well as decrease cost, some strength of the paper is negatively affected. In this research, needle-like aragonite was synthesized using $Ca(OH)_2$ and $CO_2$ as reactants in the presence of $MgCl_2$ and characterized with scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The physical and optical properties of the paper handsheets containing these needle-like aragonite fillers were evaluated. Results indicated that tensile strength, Z-direction tensile strength and folding endurance of the paper were improved by the needle-like aragonite crystals compared to the paper using commercial PCC (precipitated calcium carbonate) as filler. The stiffness of the paper handsheet on the machine direction was increased, but no evident difference in the cross direction was found. The improvement of paper strength mainly resulted from the twining effect between the aragonite whiskers and paper fibers. The optical properties of the paper were slightly decreased with the use of the needle-like aragonites compared to commercial PCC. These results suggest that paper cost can be decreased by increasing the content of needle-like aragonite filler while paper strength will not be decreased compared to PCC filler.
Hu, Zeshan,Shao, Minghao,Cai, Qiang,Jiao, Zhaojie,Zhong, Chenhua,Deng, Yulin The Korean Society for Composite Materials 2009 Advanced composite materials Vol.18 No.2
Much attention has been paid to the processing of inorganic whisker, especially calcium carbonate whisker, which can be used as reinforcement materials of polymer composite due to its low price. Unfortunately, the present synthesis technique of calcium carbonate whisker starts from calcinations of limestone, which involves high energy consumption and furthermore is a highly environment polluting reaction. In this report, needle-like aragonite was synthesized with a reversible solution reaction from limestone without calcination. Optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to characterize the morphology and crystal structure of intermediates as well as that of the product, aragonite. GCC (grinding calcium carbonate) powder was dissolved in an aqueous solution of magnesium sulfate with reflux and air flush. EDTA titration was used to evaluate reaction rate of the dissolution. A kinetics equation of the dissolution reaction was constructed, which displayed second-order kinetics with respect to the concentration of magnesium sulfate. A rate constant of $0.0015\;l^{-3}{\cdot}mol^{-1}{\cdot}h^{-1}$ was obtained. The dissolution reaction gave fiber-like magnesium hydroxide sulfate and gypsum crystal. Then needle-like aragonite with a length of $9.13\;{\pm}\;1.02\;{\mu}m$ and an aspect ratio of $5.64\;{\pm}\;1.37$ was synthesized from the dissolution product with $CO_2$ bubbling at $70^{\circ}C$.
Guangdong Hu,Jing Wang,Hui Huang,Fusheng Quan,Jian Kang,Yongyan Wu,Yuanpeng Gao,Feng Su,Minghao Shao,Yong Zhang 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.2
Transposons are widely used for geneticengineering in various model organisms. Recently, piggyBac(PB) has been developed as a transposable and efficientgene transfer tool in mammalian cells. In the present study,we developed three types of PB transposon systemscontaining a dual plasmid system (DPS), a single plasmidsystem (SPS), and a DNA-mRNA combined system (DRPS)and characterized their basic properties in HEK293 cells. The basic elements of the donor plasmid included aselectable-reporter gene expression cassette, two loxP sitesin the same orientation, a multiple cloning site, and twochicken β-globin insulator core elements. We further identifiedthe function of the selectable-reporter and examined PBintegration sites in the human genome. Moreover, wecompared the transposition efficacy and found that SPStransposed more efficiently, as compared to DPS; integrationinto the host genome was determined by measuring PBaseactivity. Results discovered the loss of PBase activity in theDRPS, indicating that this system is much more biologicallysafe, as compared to DPS and SPS. Finally, we employedthe DRPS to successfully perform a gene delivery intobovine mammary epithelial cells (BMECs). Taken together,the information from this study will improve the flexibilityof PB transposon systems and reduce the genotoxicity ofPBase in genetic engineering.
중국의 산업집적과 경제성장 간 순환누적 효과에 관한 연구 ― 2007-2018년 현급 패널 데이터를 중심으로
호세전 ( Hu Shiqian ),범자충 ( Fan Zichong ),황명호 ( Huang Minghao ) 고려대학교 중국학연구소 2020 中國學論叢 Vol.0 No.70
In this paper, we take the mutual influences between the secondary industry agglomeration and economic growth in China’s county level as the research object. The panel data simultaneous equations models are specified to analyze the existence and change characteristics of the cyclical cumulative effects of industrial agglomeration and economic growth. The results show that industrial agglomeration and economic growth not only have a significant two-way relationship, but also they achieve their own cyclical cumulative effect based on the paths of “industrial agglomeration-economic growth-industrial agglomeration” and “economic growth-industrial agglomeration-economic growth” respectively. In terms of dynamics, compared to 2007~2013, the cumulative effect of agglomeration under the periodic impact of industrial agglomeration in 2014~2018 is weakened. The increasing diffusion effect leads to the decline of the role of industrial agglomeration in the economic growth cycle accumulation. In addition, the cumulative effects of different regions show heterogeneity characteristics. The cyclical cumulative effects of industrial agglomeration and economic growth are more significant in underdeveloped counties. In some economically developed counties, however, the industry isomorphism and the demand for the upgrading of industrial structure make the cumulative effect of industrial agglomeration become weak, and the crowding effect also makes the cumulative effect of economic growth decrease.
Wenfeng Xiang,Dong Li,Minghao Hu,Wenzheng Yue,Haizhong Guo 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.5
Single-layer MoS$_2$ films were deposited on sapphire substrates by using pulsed laser deposition. The substrate temperature dependence of the structural, optical and photoluminescence properties of single-layer MoS$_2$ films was investigated. An increased substrate temperature improved the surface morphology and the crystal quality of the MoS$_2$ films. Moreover, the absorption and the photoluminescence properties of the MoS$_2$ films were enhanced. In addition, the mechanism underlying the effect of substrate temperature on the properties of single-layer MoS$_2$ films is discussed.