Preparation of nano-TiO2/purified diatomite coating and its photocatalytic properties of formaldehyde degradation

Lijian Wang,Junwei Zhao,Yujiang Wang,Shuilin Zheng 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.6

The nano-TiO2/purified diatomite composite materials with core-shell structures were prepared by hydrolysis precipitationusing purified diatomite as carrier and titanium sulfate as precursor. The composite materials were characterized bytransmission electron microscope (TEM), X-ray diffraction (XRD), low temperature nitrogen adsorption and mercuryporosimetry. The photocatalytic composite coating based on the nano-TiO2/prified diatomite composite materials wasprepared and its properties of formaldehyde degradation were investigated. Meanwhile, the degradation mechanism offormaldehyde gas was discussed. The results showed that the nano-TiO2/prified diatomite composite materials were formedcore-shell structures, and the TiO2 nanoparticles were anatase with the average size of about 10 nm?The test results show thatthe formaldehyde purification performance of the coatings has met the technical requirements of Class I materials in theChinese national standard JC/T 1074-2008.

Lineage conversion of mouse fibroblasts to pancreatic α-cells

Lijian Hui,Liangliang Sun,Beige Jiang,Limei Li,Jin Cen,Xiaotao Chen,Zhaoyun Zhang,Qinghua Wang,Xin Cheng,Yongquan Shi,Lijian Hui 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

α-cells, which synthesize glucagon, also support β-cell survival and have the capacity to transdifferentiate into β-cells. However, the role of α-cells in pathological conditions and their putative clinical applications remain elusive due in large part to the lack of mature α-cells. Here, we present a new technique to generate functional α-like cells. α-like cells (iAlpha cells) were generated from mouse fibroblasts by transduction of transcription factors, including Hhex, Foxa3, Gata4, Pdx1 and Pax4, which induce α-cell-specific gene expression and glucagon secretion in response to KCl and Arg stimulation. The cell functions in vivo and in vitro were evaluated. Lineage-specific and functional-related gene expression was tested by realtime PCR, insulin tolerance test (ITT), glucose tolerance test (GTT), Ki67 and glucagon immunohistochemistry analysis were done in iAlpha cells transplanted nude mice. iAlpha cells possess α-cell function in vitro and alter blood glucose levels in vivo. Transplantation of iAlpha cells into nude mice resulted in insulin resistance and increased β-cell proliferation. Taken together, we present a novel strategy to generate functional α-like cells for the purposes of disease modeling and regenerative medicine.

Locally Resonant Periodic Wave Barriers for Vibration Isolation in Subway Engineering

Lijian Lei,Linchang Miao,Chao Li,Xiaodong Liang,Junjie Wang 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.4

Subway transportation is being promoted worldwide to effectively solve urban congestion. However, the vibration induced by subway traffic has caused a major adverse impact on building safety, precision instrument operation and human health. Wave barriers have been proven effective in mitigating ground vibration, whereas they have some limitations in achieving ideal attenuation zone and high efficiency to cover the low-frequency vibration in underground railway system. Based on locally resonant phononic crystals theory, this paper designs three-component locally resonant periodic wave barriers (LRPWBs), and investigates the effects of geometrical and material parameters on the bandgap features in detail. The band structures are calculated using improved plane wave expansion (IPWE), the transmission spectra and vibration modes are obtained by finite element method (FEM). The results indicate LRPWBs are able to give lower and wider bandgap to cover the main frequency of subway environment, which is proved by time and frequency domain analysis. For the bandgap mechanism, the local resonance features of LRPWBs result in the energy conversion between kinetic energy and elastic strain energy, thus the elastic wave energy is localized in resonance unit and then the locally resonant bandgap is created. In addition, the bandgap can be adjusted by carefully selecting proper geometrical and material parameters to actualize low-frequency broadband attenuation. Further studies about multi-oscillator system indicate that the appropriate combination of multiple LRPWBs are conductive to diverse and broad bandgaps. The investigations can provide inspiration for periodic wave barriers design in multi-frequency vibration attenuation field.

The formation process of the Mengyejing potash deposit, Yunnan, China: evidence from geochemical and petrological characteristics

Lijian Shen,Chenglin Liu,Jian-xin Zhao,Yuexing Feng,Licheng Wang 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.5

Two types of potash ores were sampled from the Mengyejing potash deposit (the MPD) which is the only ancient potash deposit ever found in China. Geochemical analyses, including Br, K, Mg and some heavy metals, were performed on those samples. The relatively consistent Br contents (141.42 to 763.67 ppm) in both bedded potash and veined potash ores show that the potashforming brine was likely derived from seawater. K contents and Br/Cl ratios of the veined potash ores are relatively high in contrast to bedded potash ores. The K/Br ratios of veined potash ores exhibit a positive correlation with Br contents, which is opposite to that of the bedded potash ore of the MPD and potassium-salts from the evaporation of modern seawater. The contents of heavy metals in veined potash ores are much higher than those of bedded potash ores in the MPD and potash in other evaporite basins of the world. Sr and S isotopic compositions of these two types of potash ores suggest that the brines for precipitating veined potash were formed by mixing of connate waters (seawater or/and continental freshwater) and hydrothermal fluids. The geochemical and petrological characteristics of the veined potash ores indicate that the brine for forming veined potash orebodies caused by dissolution of previous bedded potash orebodies by hydrothermal fluids. The veined potash orebodies were formed through a cooling process by which sylvite precipitated first prior to halite.

Image Denoising Based on Adaptive Fractional Order Anisotropic Diffusion

( Jimin Yu ),( Lijian Tan ),( Shangbo Zhou ),( Liping Wang ),( Chaomei Wang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Recently, the method based on fractional order partial differential equation has been used in image processing. Usually, the optional order of fractional differentiation is determined by a lot of experiments. In this paper, a denoising model is proposed based on adaptive fractional order anisotropic diffusion. In the proposed model, the complexity of the local image texture is reflected by the local variance, and the order of the fractional differentiation is determined adaptively. In the process of the adaptive fractional order model, the discrete Fourier transform is applied to compute the fractional order difference as well as the dynamic evolution process. Experimental results show that the peak signal-to-noise ratio (PSNR) and structural similarity index measurement (SSIM) of the proposed image denoising algorithm is better than that of other some algorithms. The proposed algorithm not only can keep the detailed image information and edge information, but also obtain a good visual effect.

Manufacture and Performance of Textile-ramie Fiber Reinforced Anionic Polyamide 6 Composites

Hao Shi,Lijian Xia,Zonglei Guo,Abin Sun,Hui Wang,Ze Kan 한국섬유공학회 2019 Fibers and polymers Vol.20 No.8

A vacuum assistant resin infusion moulding (VARIM) was adopted to prepare a new-style and environmentalfriendly thermoplastic composite consisting of anionic polyamide-6 (APA-6) and textile-ramie fiber. However, the intensivepolymerization-inhibition and fiber-discoloration phenomena were found in the reactive processing. In order to overcomethese problems, two methods were used to suppress the reaction between the ramie fiber and APA-6, which are the surfacemodification of ramie fiber and a new initiator with a low activity. Finally, the inhibition and discoloration phenomena weresuppressed significantly, which overcame the major challenge during the preparation of ramie fiber reinforced APA-6composites by reactive processing. The composites showed a good polymerization during VARIM process. The tensilestrength and flexural modulus of the obtained composites were increased by 21 % and 26 % respectively compared with thatof pure APA-6. It is important to find that there were some interactions between APA-6 and ramie fiber, which produced agood interface characters. This work not only opens new avenues for the development of renewable composites, but alsofurther broadens the applications of the natural fibers.

The application of modified isochronal well test in a low-permeability condensate gas field

Zhaojing Zhou,Xiuwei Wang,Xue Miao,Kangning Qian,Lijian Li,Peng Xu,Xiuqin Lu 한국자원공학회 2019 Geosystem engineering Vol.22 No.6

The modified isochronal well test is a deliverability test method suitable for gas wells in low-permeability gas reservoirs. Generally, the absolute open flow of gas wells is determined by modified isochronal well test, thereby establishing a reasonable working system for gas wells. It is also possible to obtain gas layer physical parameters, gas reservoir engineering parameters, heterogeneity, boundary characteristics, etc. In this paper, the actual test data of a condensate gas field are applied. By modified isochronal well test analysis, not only the deliverability equation of the gas well is obtained, but also the absolute open flow is determined. At the same time, the formation parameters such as reservoir permeability and skin factor are obtained and the acidification effect is evaluated.

Systematic study on temperature and time‑varying characteristics of SiC MOSFET static parameters at 200 °C

Xiao Ma,Jianing Wang,Lijian Ding 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

Silicon carbide (SiC) devices can be used in high-temperature conditions due to advancements in packaging technology and manufacturing processes. However, a systematic evaluation of SiC device performances at high temperatures is necessary. First, this study implements a number of static tests on SiC MOSFETs from several manufacturers in environments up to 230 °C to obtain the variation patterns of SiC MOSFET static parameters at different temperatures and to characterize the static properties of SiC MOSFETs at high temperatures. Second, the long-term high-temperature tolerances of 200 °C devices and 175 °C conventional commercial devices are compared. Static test results at different aging stages show that the performance for each device type changes to different degrees at high temperatures. However, these devices have recovery characteristics during the process of cooling to room temperature. Finally, the static parameter characteristics of SiC MOSFETs are summarized in terms of time and temperature to provide a theoretical basis for applying SiC power devices at high temperatures.

Gasification investigations of coal and biomass blends for high purity H2 production with carbon capture potential

Dingkun Yuan,Kang Zhang,Lijian Wang,Lingfeng Jin,Xutao Guo,Guangxue Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Biomass is carbon-neutral and has the carbon-negative potential if combined with carbon capture andstorage (CCS). This study investigated the thermochemical conversion to high-purity hydrogen of a typicallignite (BYH) and seaweed biomass (BS) with carbon capture in a designed fixed-bed reactor at moderateconditions (1 atm, 873 K). High-purity hydrogen of 486.91–801.5 ml/g-blends with suppressed CO2formation was produced in the alkaline gasification. The alkali can decompose the coal/biomass molecularstructures, in-situ capture CO2 and control the gases to high-purity H2 (80.1%–93.2%). The synergisticeffect of coal and biomass changes the gas evolution behaviors and impacts the chemical structures of thechar. The abundant SiO2 and Al2O3 in the coal can inhibit the catalytic activities of earth alkali metals inthe biomass, but not much. These results are significant to the future development of low-carbon renewableenergy techniques.

Experimental Investigation on the Bond Behavior of Deformed Bars in a Class of Structural Expanded Polystyrene (EPS) Concrete

Chao Li,Linchang Miao,Quan You,Lijian Lei,Xiaodong Liang,Junjie Wang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12

The structural expanded polystyrene (EPS) concrete (above 35 MPa) has the potential to be used as metro track bed to reduce and isolate vibration, but its bond behavior is still unclear. This inhibits its application because it is often used in combination with reinforcing bar. In this paper, a class of structural EPS concrete (above 35 MPa) was developed. Based on this, a series of pull-out tests were conducted and the bond behavior of deformed bars in these structural EPS concretes was investigated. In addition, effects of rebar bond length and rebar diameter were analyzed in detail. Experimental results indicate that the structural EPS concrete suffers splitting failure more easily than the conventional concrete (CC). Increase of EPS replacement, rebar bond length or rebar diameter tends to cause the splitting failure of structural EPS concrete. Moreover, with increase of EPS replacement, the failure process is less explosive and more gradual. The stress-slip relationships of the most specimens show three stages, namely linear ascending, non-linear progression, and descending stages. The bond strength of structural EPS concrete is found depended linearly on the power function of its compressive strength, relative cover thickness (c/d) and relative rebar bond length (L/d), respectively. Accordingly, a bond strength prediction model was formulated, and it can precisely predict the bond strength of deformed bars in structural EPS concrete, specimens failing in splitting or splitting-pull out modes, and no fiber added. The results can provide reference for the design of structural EPS concrete.