Dynamic measurements of hydrate based gas separation in cooled silica gel

Mingjun Yang,Yongchen Song,Lanlan Jiang,Xiaojing Wang,Weiguo Liu,Yuechao Zhao,Yu Liu,Shanrong Wang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

Hydrate based gas separation is a promising method for carbon dioxide capture. The purpose of thisstudy is to analyze hydrates formation and dissociation characters when gas mixture flows throughcooled silica gel. The additives mixture (THF/SDS) was used to saturate the silica gel partly, and gasmixture (CO2/H2) was injected into it to form hydrates. Magnetic resonance imaging (MRI) images wereobtained using fast spin echo multi-slice pulse sequence. Hydrates saturations were calculatedquantitatively using MRI data. The experimental results showed that the optimal initial solutionsaturation was 34.2% in this investigation. The gas component was analyzed to assess the separationefficiency. For hydrates dissociation processes at 1 atmospheric pressure, CO2 concentrations increasedobviously. Half of the six cycles showed that more than 85.00 mol% CO2 contained in the capture gas, andthe lowest CO2 concentration was 64.83 mol%. Hydrate blockages appeared frequently, which restrictedthe contact of gas and solution and caused the incomplete transformations of residual solution tohydrates. It was a key restricted factor for hydrate based CO2 capture.

Estimates of linkage disequilibrium and effective population sizes in Chinese Merino (Xinjiang type) sheep by genome-wide SNPs

Shudong Liu,Sangang He,Lei Chen,Wenrong Li,Jiang Di,Mingjun Liu 한국유전학회 2017 Genes & Genomics Vol.39 No.7

Knowledge of linkage disequilibrium (LD) is important for effective genome-wide association studies and accurate genomic prediction. Chinese Merino (Xinjiang type) is well-known fine wool sheep breed. However, the extent of LD across the genome remains unexplored. In this study, we calculated autosomal LD based on genomewide SNPs of 635 Chinese Merino (Xinjiang type) sheep by Illumina Ovine SNP50 BeadChip. A moderate level of LD (r2 ≥ 0.25) across the whole genome was observed at short distances of 0–10 kb. Further, the ancestral effective population size (Ne) was analyzed by extent of LD and found that Ne increased with the increase of generations and declined rapidly within the most recent 50 generations, which is consistent with the history of Chinese Merino sheep breeding, initiated in 1971. We also noted that even when the effective population size was estimated across different single chromosomes, Ne only ranged from 140.36 to 183.33 at five generations in the past, exhibiting a rapid decrease compared with that at ten generations in the past. These results indicated that the genetic diversity in Chinese Merino sheep recently decreased and proper protective measures should be taken to maintain the diversity. Our datasets provided essential genetic information to track molecular variations which potentially contribute to phenotypic variation in Chinese Merino sheep.

Analysis and research on dynamic characteristics of 3D braided composite two-stage reducer case

Weiliang Zhang,Xupeng Wang,Xiaomin Ji,Xinyao Tang,Fengfeng Liu,Shuwei Liu,Mingjun Liu,Xiao-Long Gao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

Based on the analysis of the movement rule of 3D five-way braided yarn, the 3D five-way braided case model is divided into three parts: base, case bottom plate and case wall. According to the characteristics of each part, the braiding and forming principle of a 3D five-way composite case was analyzed. Under the assumption of ignoring the influence of friction, bearing and other factors on the system, the differential equations of motion of the two-stage gear transmission system with case were established. The two-stage gear transmission system was numerically analyzed by Euler method, and the influence of dimensionless meshing frequency, clearance, case mass and damping on the dynamic characteristics of the transmission system was studied. After that, high and low frequency disturbance was applied to the input case. The research shows that the damping ratio of the composite case increases and the low frequency attenuation is accelerated due to the decrease of the case mass, so the composite case has better shock resistance to low frequency interference.

Distribution Characteristics of Grassland Coverage Change in Tibetan Plateau Since 1982

Mingjun DING,Yi-Li Zhang,Linshan LIU 대한지리학회 2011 대한지리학회 컨퍼런스 자료집 Vol.- No.6

Multicolor tunable luminescence and energy transfer mechanism in a novel single-phase KBaGd(WO₄)₃:Tb³⁺, Eu³⁺ phosphor for NUV WLEDs

Song, Mingjun,Zhao, Wang,Ran, Weiguang,Xue, Junpeng,Liu, Yanliang,Jeong, Jung Hyun Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.803 No.-

<P><B>Abstract</B></P> <P>In this research, a series of Tb<SUP>3+</SUP> and/or Eu<SUP>3+</SUP> doped KBaGd(WO<SUB>4</SUB>)<SUB>3</SUB> (KBGW for short) phoshpors were prepared by sol-gel method and characterized by X-ray diffraction (XRD), FT-IR and Raman spectra, scanning electron microscope (SEM), excitation and emission spectra, and luminescent decay curves. The results of XRD, SEM, FT-IR and Raman spectra confirmed that a single phase of KBGW with smooth surface and uniform particle size can be synthesized by sol-gel method. Under 250 or 378 nm excitation, multicolor tunable emissions from green to red were achieved in the KBGW:Tb<SUP>3+</SUP>, Eu<SUP>3+</SUP> phosphors by suitably controlling the ratios of Eu<SUP>3+</SUP>/Tb<SUP>3+</SUP>. The energy transfer efficiencies and mechanisms between Eu<SUP>3+</SUP> and Tb<SUP>3+</SUP> were investigated on the basis of photoluminescence (PL) spectra and luminescent decay curves, and a graphic analysis on the energy transfer process between Tb<SUP>3+</SUP> and Eu<SUP>3+</SUP> was presented. The temperature-dependent PL spectra of Eu<SUP>3+</SUP> and/or Tb<SUP>3+</SUP> doped KBGW were recorded and the thermal quenching behavior of the phosphors was analyzed in the framework of crossover model. At the end, green, red and white LEDs were fabricated with the as-prepared KBGW:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphors, and the excellent electroluminescence parameters suggest that the KBGW:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphors may be a component candidate for NUV excited WLEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A color tunable KBaGd(WO<SUB>4</SUB>)<SUB>3</SUB>:Tb<SUP>3+</SUP>/Eu<SUP>3+</SUP> phosphor was firstly prepared by sol-gel method. </LI> <LI> Its morphology, luminescent property and thermal stability were studied in detail. </LI> <LI> The emission color was tuned from green to red by changing the doping ratio of Eu/Tb. </LI> <LI> The energy transfer is demonstrated to be accomplished by dipole-dipole interactions. </LI> <LI> Green, red and white LEDs were fabricated and their performance were investigated. </LI> </UL> </P>

Microwave-Assisted Fabrication of Recyclable CdS/Fe3O4/rGO Photocatalysts to Improve the Photocatalytic Performance Under Visible Light

XINLIN LIU,Yingying Qin,Mingjun Zhou,Yongsheng Yan 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

A unique CdS/Fe3O4/rGO composite photocatalyst is successfully synthesized by the microwave method. It displays promising photocatalytic activity towards the photo-degrading of tetracycline (TC) in aqueous solution, the degradation rate of TC is 69% with adding 0.1 g CdS/Fe3O4/rGO photocatalyst into 20 mg/L tetracycline for 2 h under visible light irradiation. Furthermore, the mechanism was systematically investigated by active species trapping experiment. It can be known that e? was the major active species in the photodegradation process and the possible process of charge transfer for CdS/Fe3O4/rGO was proposed based on the experimental results. The as-prepared samples were carefully evaluated by XRD, TEM, XPS, VSM, PL spectra, Raman spectrometer.

Large eddy simulation on the turbulent mixing phenomena in 3×3 bare tight lattice rod bundle using spectral element method

Ju, Haoran,Wang, Mingjun,Wang, Yingjie,Zhao, Minfu,Tian, Wenxi,Liu, Tiancai,Su, G.H.,Qiu, Suizheng Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

Subchannel code is one of the effective simulation tools for thermal-hydraulic analysis in nuclear reactor core. In order to reduce the computational cost and improve the calculation efficiency, empirical correlation of turbulent mixing coefficient is employed to calculate the lateral mixing velocity between adjacent subchannels. However, correlations utilized currently are often fitted from data achieved in central channel of fuel assembly, which would simply neglect the wall effects. In this paper, the CFD approach based on spectral element method is employed to predict turbulent mixing phenomena through gaps in 3 × 3 bare tight lattice rod bundle and investigate the flow pulsation through gaps in different positions. Re = 5000,10000,20500 and P/D = 1.03 and 1.06 have been covered in the simulation cases. With a well verified mesh, lateral velocities at gap center between corner channel and wall channel (W-Co), wall channel and wall channel (W-W), wall channel and center channel (W-C) as well as center channel and center channel (C-C) are collected and compared with each other. The obvious turbulent mixing distributions are presented in the different channels of rod bundle. The peak frequency values at W-Co channel could have about 40%-50% reduction comparing with the C-C channel value and the turbulent mixing coefficient β could decrease around 25%. corrections for β should be performed in subchannel code at wall channel and corner channel for a reasonable prediction result. A preliminary analysis on fluctuation at channel gap has also performed. Eddy cascade should be considered carefully in detailed analysis for fluctuating in rod bundle.

CFD simulation of flow and heat transfer characteristics in a 5×5 fuel rod bundles with spacer grids of advanced PWR

Wang Yingjie,Wang Mingjun,Ju Haoran,Zhao Minfu,Zhang Dalin,Tian Wenxi,Liu Tiancai,Qiu Suizheng,Su G.H. 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

High fidelity nuclear reactor fuel assembly simulation using CFD method is an effective way for the structure design and optimization. The validated models and user practice guidelines play critical roles in achieving reliable results in CFD simulations. In this paper, the international benchmark MATiS-H is studied carefully and the best user practice guideline is achieved for the rod bundles simulation. Then a 5 5 rod bundles model in the advanced pressurized water reactor (PWR) is established and the detailed three-dimensional thermal-hydraulic characteristics are investigated. The influence of spacer grids and mixing vanes on the flow and hear transfer in rod bundles is revealed. As the coolant flows through the spacer grids and mixing vanes in the rod bundles, the drastic lateral flow would be induced and the pressure drop increases significantly. In addition, the heat transfer is enhanced remarkably due to the strong mixing effects. The calculation results could provide meaningful guidelines for the design of advanced PWR fuel assembly

Carbon quantum dots modified CdSe loaded reduced graphene oxide for enhancing photocatalytic activity

Pengwei Huo,Jingru Guan,Mingjun Zhou,CHANGCHANG MA,XINLIN LIU,Yongsheng Yan,Shouqi Yuan 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.50 No.-

Carbon quantum dots (CQDs)/CdSe/reduced graphene oxide (rGO) was fabricated by hydrothermalmethod. The structures, optical and electronic properties of as-obtained photocatalysts were analyzed bytransmission electron microscopy (TEM), X-ray diffraction (XRD) and photoelectrochemical testing. Thephotocatalytic performances were investigated by degradation of tetracycline hydrochloride (TC HCl). The results showed CQDs modified CdSe loaded rGO could effectively remove TC HCl, the CdSe modifiedwith 7 mL CQDs showed higher photocatalytic degradation rate; the 5 wt% loaded rGO for CQDs/CdSeshowed highest photocatalytic activity. The photocatalytic mechanism exhibited OH, O2and 1O2radicals play key roles

Overexpression of NPC1L1 in the livers of transgenic Bama miniature pigs accelerates lipid peroxidation

Chongli Xu,Yu Liu,Yuchen Gong,Xinping Duan,Xiaochun Tang,Mingjun Zhang,Daxin Pang,Liqing Yu,Hongwei Zhao,Hongsheng Ouyang 한국유전학회 2015 Genes & Genomics Vol.37 No.2

Although Niemann-Pick C1-Like 1 (NPC1L1)plays a key role in intestinal cholesterol absorption, regulatingcholesterol metabolism and maintaining cholesterolmetabolic homeostasis, the molecular mechanism ofNPC1L1 in lipid-metabolism disorders leading to liverdisease remains largely unknown. Previous studies haveshown that NPC1L1 is related with the development offatty liver. Therefore, we hypothesized that NPC1L1 playsan important role in lipid-metabolism disorders and liverdisease by affecting the transcription of certain genesinvolved in lipid synthesis. To further elucidate the functionof NPC1L1, especially in the liver, we used somaticcellnuclear transfer to establish transgenic pigs thatexpressed human NPC1L1 in their livers. We investigatedsuperoxide dismutase activities and the levels of free fattyacids and malondialdehyde, a biomarker of lipid peroxidation. Superoxide dismutase activities significantlydecreased, and free fatty acid and malondialdehyde levelssignificantly increased in the NPC1L1 transgenic pigs,indicating that the overexpression of NPC1L1 in the liverresulted in severe lipid peroxidation. Our findings suggestthat NPC1L1 plays an important role in lipid-metabolismdisorders and liver disease.