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Now showing items 1 - 16 of 109

  • Effect of triethanolamine hydrochloride on the performance of cement paste

    Yang, Xiaojie   Liu, Jiasen   Li, Haoxin   Xu, Linglin   Ren, Qiang   Li, Lin  

    Triethanolamine (C6H15NO3, TEA) is one of the known organic amine accelerators for the cement-based materials. Triethanolamine hydrochloride (C6H15NO3 center dot HCl, TEA center dot HCl), part of whose molecular structure is the same as TEA, can also be regarded as chloride. Thus the water requirement for the normal consistency, setting time, strength, hydration heat liberation, calcium hydroxide (CH) and ettringite (AFt) contents in the hardened paste with TEA center dot HCl were analyzed and the effect of TEA center dot HCl on the performance of cement paste was studied to assess the feasibility of TEA center dot HCl used as an identical accelerator. The results indicate that moderate TEA center dot HCl decreases the water requirement for the normal consistency and this decline is related to the formation of the absorbed film on the cement particle. Zeta electric potential result also proves the appearance of the absorbed film. It also shortens the setting times and alters strengths. But the alterations of setting times and strengths depend on the TEA center dot HCl content. Heat liberation result implies that it delays the end time of the induction period and also postpones tricalcium silicate (3CaO center dot SiO2, C3S) hydration at early age, however moderate TEA center dot HCl increases the rate of C3S hydration in accelerated phase. Excessive TEA center dot HCl accelerates the AFt conversion to monosulfoaluminate (AFm) after several hours. The conversion product is the AFm with 14 H2O. TEA center dot HCl changes the total heat liberation, and these pastes with more TEA center dot HCl liberate more heat before about 12 h, but this case is reverse after about 12 h. X-ray powder diffraction (XRD) and differential thermal analysis (DTA) results conformably confirm that excessive TEA center dot HCl delays C3S hydration and decreases CH content in the hardened paste, but it increases the AFt content in the hardened paste. Hardened pastes with TEA center dot HCl provide the higher content of AFt than the control even at 28d. Heat liberation, CH and AFt contents are closely responsible for the results of the setting times and strengths. These results will provide a reference for the TEA center dot HCl application as an accelerator in the practice. (C) 2018 Elsevier Ltd. All rights reserved.
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  • A stochastic micromechanical framework for hybrid fiber reinforced concrete

    Jiang, Zhengwu   Yang, Xiaojie   Yan, Zhiguo   Chen, Qing   Zhu, Hehua   Wang, Yaqiong   Ju, J. Woody   Fan, Zhihong   Li, Haoxin  

    A stochastic micromechanical framework is presented to predict the probabilistic behavior of the hybrid fiber reinforced concrete (HFRC). The proposed framework consists of the stochastic descriptions for the material's microstructures, deterministic micromechanical model for HFRC and maximum entropy based stochastic simulation program. The HFRC is represented as multiphase composite composed of the aggregate, the interfacial transition zone (ITZ), the bulk cement paste and different types of fibers. Multi-level homogenization schemes are presented to predict the material's effective properties, where the effects of aggregates, ITZs and multi-types of fibers are quantitatively calculated. By modeling the volume fractions and properties of constituents as stochastic, we extend the deterministic framework to stochastic to incorporate the inherent randomness of effective properties among different specimens. Maximum entropy based simulation procedures are employed to characterize the material's probabilistic behavior, including different order moments and the probability density function. Numerical examples including limited experimental validations, comparisons with existing micromechanical models, commonly used probability density functions and the direct Monte Carlo simulations indicate that the proposed models provide an accurate and computationally efficient framework in characterizing the material's effective properties. Finally, the effects of different fibers and ITZs on the materials' macroscopic probabilistic behaviors are investigated based on our proposed stochastic micromechanical framework.
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  • Ag-decorated TiO2 nanofibers for highly efficient dye sensitized solar cell

    Sun, Junmei   Yang, Xiaojie   Zhao, Li   Dong, Binghai   Wang, Shimin  

    For dye sensitized solar cell, the modification of noble metals plays an important role in improving the light absorption of TiO2 films and reducing the recombination of electrons and holes. The composite photoanode of TiO2 nanoparticles/nanofibers (NP/NF) was prepared and soaked in AgNO3 solution at 0.01 mol/L, and the silver content was obtained according to different reduction times. The power conversion efficiency (PCE) increased from 5.39% to 6.36%. The PCE of composite photoanode increased by 18.0% compared with that of the photoanode without Ag modification. (C) 2019 Elsevier B.V. All rights reserved.
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  • Effect of triethanolamine hydrochloride on the performance of cement paste

    Yang, Xiaojie   Liu, Jiasen   Li, Haoxin   Xu, Linglin   Ren, Qiang   Li, Lin  

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  • LARGE DEFORMATION TENSILE TESTING SYSTEM

    A large deformation tensile testing system, for use in testing a large deformation tensile of an anchor rod or an anchor rode, comprising a main machine frame (1), a rear collet component (2) arranged at a first position on the longitudinal direction of the main machine frame (1), a front collet component (3) movably arranged at a second position on the longitudinal direction of the main machine frame (1), a telescoping apparatus (4), a measurement and control apparatus, where a sensor module thereof senses the displacement and real-time tensile of the telescoping apparatus to form real-time data to be transmitted to an analysis module and a control module, the control module that controls, on the basis of a set measurement and control scheme and of an input of the sensor module, a testing process to proceed according to a set testing condition, the analysis module for analyzing the input of the sensor module to form a test result, and an output module for outputting same. The large deformation tensile testing system is capable of deriving a statics parameter of the anchor rod or anchor rode being tested.
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  • Characteristics of in situ stress field at Qingshui coal mine

    Yang, Xiaojie   Pang, Jiewen   Lou, Haopeng   Fan, Lipeng  

    Abstract In this study, the characteristics of geological structure at Qingshui coal mine were analyzed. And the hollow inclusion strain cell overcoring method was used to obtain the in situ stress. The effect of in situ stress on the stability of soft rock roadway was analyzed. The results show that the maximum principal stress is in the horizontal direction with a northeast orientation and has a value of about 1.2–1.9 times larger than gravity; the right side of roadway roof and floor is easily subject to serious deformation and failure, and the in situ stress is found to be a major factor. This paper presents important information for developing countermeasures against the large deformation of the soft rock roadway at Qingshui coal mine.
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  • Effect of wetting and drying cycles on microstructure of rock based on SEM

    Yang, Xiaojie   Wang, Jiamin   Zhu, Chun   He, Manchao   Gao, Yang  

    To study the effect of periodic water circulation on rock mass, chlorite-amphibolite rocks from the slope of Nanfen open-pit iron mine in Liaoning province were chosen as the engineering samples and were investigated using uniaxial compressive experiment and scanning electron microscopy. The effect of different wetting and drying cycles on the mechanical properties and microstructure of the rocks was investigated. The characteristics of pore parameters from the SEM images were obtained by Image Pro Plus image processing software. The results show that with the increase in number of wetting and drying cycles, the uniaxial compressive strength of the rock decreases and the porosity increases significantly. The weakening of macroscopic mechanical properties of rocks is closely related to the changes in microstructures of rocks. The water-rock interaction changes the size, shape and porosity of the rock pores and then affects its mechanical properties. Based on the combination of macro and micro, quantitative analysis of the weakening process of rocks subjected to wet and dry cycles can provide a better reference index for evaluating the stability of geotechnical engineering.
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  • Functional akund fibres by loading of carbon dots through an in-situ method

    Yang, Xiaojie   An, Xueqin  

    An in-situ synthesis method for loading Carbon Dots (CDs) on the surface and the inner cavities (lumens) of akund fibres has been presented. CDs were successfully loaded on the lumens of akund and AgNPs were also synthesized on the inner surface of fibres by using CDs on the surface of akund as reductant. The inner and outer surface morphology of akund-CDs and akund-CDs/AgNPs were obtained by using scanning electron microscope (FESEM). The fluorescence (FL) properties of CDs on the inner surface of akund-CDs and akund-CDs/AgNPs were compared by using confocal laser scanning microscopy (LSCM) and it showed that the FL intensity of CDs on akund-CDs was much stronger than that on akund-CDs/AgNPs. The microstructures of CDs on akund-CDs and akund-CDs/AgNPs were also probed by using time-resolved FL spectra for the first time, and the results showed that the microstructures of CDs on akund-CDs and akund-CDs/AgNPs were different. The FL property, load capacity, stability, antioxidant activity and washability of akund-CDs synthesized by different methods were also measured, and it was found that the in-situ method was much better than the traditional simple soaking method. This work suggested a promising approach to load nanoparticles on the lumens of akund, which endows akund with many functions to be applied in textile industry.
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  • PAG1, a cotton brassinosteroid catabolism gene, modulates fiber elongation.

    Yang, Zuoren   Zhang, Chaojun   Yang, Xiaojie   Liu, Kun   Wu, Zhixia   Zhang, Xueyan   Zheng, Wu   Xun, Qingqing   Liu, Chuanliang   Lu, Lili   Yang, Zhaoen   Qian, Yuyuan   Xu, Zhenzhen   Li, Changfeng   Li, Jia   Li, Fuguang  

    Cotton (Gossypium hirsutum) is the major source of natural textile fibers. Brassinosteroids (BRs) play crucial roles in regulating fiber development. The molecular mechanisms of BRs in regulating fiber elongation, however, are poorly understood. pagoda1 (pag1) was identified via an activation tagging genetic screen and characterized by genome walking and brassinolide (BL) supplementation. RNA-Seq analysis was employed to elucidate the mechanisms of PAG1 in regulating fiber development. pag1 exhibited dwarfism and reduced fiber length due to significant inhibition of cell elongation and expansion. BL treatment rescued its growth and fiber elongation. PAG1 encodes a homolog of Arabidopsis CYP734A1 that inactivates BRs via C-26 hydroxylation. RNA-Seq analyses showed that the constitutive expression of PAG1 downregulated the expression of genes involved in very-long-chain fatty acids (VLCFA) biosynthesis, ethylene-mediated signaling, response to cadmium, cell wall development, cytoskeleton organization and cell growth. Our results demonstrate that PAG1 plays crucial roles in regulating fiber development via controlling the level of endogenous bioactive BRs, which may affect ethylene signaling cascade by mediating VLCFA. Therefore, BR may be a critical regulator of fiber elongation, a role which may in turn be linked to effects on VLCFA biosynthesis, ethylene and cadmium signaling, cell wall- and cytoskeleton-related gene expression. =C2=A9 2014 The Authors. New Phytologist =C2=A9 2014 New Phytologist Trust.
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  • Effect of wetting and drying cycles on microstructure of rock based on SEM

    Yang, Xiaojie   Wang, Jiamin   Zhu, Chun   He, Manchao   Gao, Yang  

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  • Quantitative phosphoproteomic analysis of the molecular substrates of sleep need.

    Wang, Zhiqiang   Ma, Jing   Miyoshi, Chika   Li, Yuxin   Sato, Makito   Ogawa, Yukino   Lou, Tingting   Ma, Chengyuan   Gao, Xue   Lee, Chiyu   Fujiyama, Tomoyuki   Yang, Xiaojie   Zhou, Shuang   Hotta-Hirashima, Noriko   Klewe-Nebenius, Daniela   Ikkyu, Aya   Kakizaki, Miyo   Kanno, Satomi   Cao, Liqin   Takahashi, Satoru   Peng, Junmin   Yu, Yonghao   Funato, Hiromasa   Yanagisawa, Masashi   Liu, Qinghua  

    Sleep and wake have global effects on brain physiology, from molecular changes1-4 and neuronal activities to synaptic plasticity3-7. Sleep-wake homeostasis is maintained by thegeneration of a sleep need that accumulates during waking and dissipates during sleep8-11. Here we investigate the molecular basis of sleep need using quantitative phosphoproteomic analysis of the sleep-deprived and Sleepy mouse models of increased sleep need. Sleep deprivation induces cumulative phosphorylation of the brain proteome, which dissipates during sleep. Sleepy mice, owing to a gain-of-function mutation in the Sik3 gene 12 , have a constitutively high sleep need despite increased sleep amount. The brain proteome of these mice exhibits hyperphosphorylation, similar to that seen in the brain of sleep-deprived mice. Comparison of the two models identifies 80 mostly synaptic sleep-need-index phosphoproteins (SNIPPs), in which phosphorylation states closely parallel changes of sleep need. SLEEPY, the mutant SIK3 protein, preferentially associates with and phosphorylates SNIPPs. Inhibition of SIK3 activity reduces phosphorylation of SNIPPs and slow wave activity during non-rapid-eye-movement sleep, the best known measurable index of sleep need, in both Sleepy mice and sleep-deprived wild-type mice. Our results suggest that phosphorylation of SNIPPs accumulates and dissipates in relation to sleep need, and therefore SNIPP phosphorylation is a molecular signature of sleep need. Whereas waking encodes memories by potentiating synapses, sleep consolidates memories and restores synaptic homeostasis by globally downscaling excitatory synapses4-6. Thus, the phosphorylation-dephosphorylation cycle of SNIPPs may represent a major regulatory mechanism that underlies both synaptic homeostasis and sleep-wake homeostasis.=20
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  • Enterovirus 71 2C Protein Inhibits NF-kappaB Activation by Binding to RelA(p65).

    Du, Haiwei   Yin, Peiqi   Yang, Xiaojie   Zhang, Leiliang   Jin, Qi   Zhu, Guofeng  

    Viruses evolve multiple ways to interfere with NF-kappaB signaling, a key regulator of innate and adaptive immunity. Enterovirus 71 (EV71) is one of primary pathogens that cause hand-foot-mouth disease. Here, we identify RelA(p65) as a novel binding partner for EV71 2C protein from yeast two-hybrid screen. By interaction with IPT domain of p65, 2C reduces the formation of heterodimer p65/p50, the predominant form of NF-kappaB. We also show that picornavirus 2C family proteins inhibit NF-kappaB activation and associate with p65 and IKKbeta. Our findings provide a novel mechanism how EV71 antagonizes innate immunity. =20
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  • EARTHQUAKE DISASTER EARLY-WARNING AND FORECASTING METHOD AND SYSTEM THEREOF

    An earthquake disaster early-warning and forecasting method and system are provided. The method comprises setting a monitoring cable and a force sensor among fault planes of a seismic belt so as to detect the shearing force between the fault planes of the seismic belt, the force sensor and the monitoring cable are connected so as to sense the tension of the cable; calculating the shearing force between the fault planes of the seismic belt according to the following formuIa (I); wherein P is the shearing force between the fault planes of the seismic belt, M is the tension of the monitoring cable, α is a reinforcing angle of the tension of the monitoring cable, θ is an inclination between the fault plane of the seismic belt and horizon plane, φ is a weighted mean value of friction angles among each soil layer of the fault crush zone, and C is a weighted mean value of cohesive strengths among each soil layer of the fault crush zone; sending an earthquake early-warning and forecasting when the shearing force between the fault planes of the seismic belt exceeds an early-warning value.
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  • Toxic metal biosorption by macrocolonies of cyanobacterium Nostoc sphaeroides Kutzing

    Jiang, Jinhui   Zhang, Nan   Yang, Xiaojie   Song, Lirong   Yang, Shao  

    The cyanobacterium Nostoc sphaeroides Kutzing is expected to be effective in toxic metal adsorption as it produces abundant exopolysaccharides with functional groups. Therefore, the adsorption properties of Cu2+, Cd2+, Cr3+, Pb2+, Ni2+, and Mn2+ on fresh macrocolonies and algal powder of N. sphaeroides were compared at pH 5 and 25 degrees C. The adsorption capacity of fresh biomass for Pb2+ and of algal powder for Pb2+ and Cr3+ were highest in single metal solutions. Compared to the fresh biomass, the metal adsorption capacities of algal powder were similar for Ni2+, Cd2+, and Pb2+ and slightly greater for Cr3+, but they were markedly smaller for Mn2+ and Cu2+. Coexisting ions ( in tap water or in multiple solutions) significantly decreased the metal adsorption capacity, except for Cr3+ in tap water. The Pb2+ and Cr3+ adsorption dynamic process fitted the pseudo- secondorder model well, showing fast adsorption at the first stage in 10 and 20 min, respectively. Higher pH in acidic ranges favored the adsorption greatly. The Langmuir isotherm model was suitable for explaining the adsorption, and the maximum adsorption capacities were 116.28 and 22.37 mg g- 1 for Pb2+ and Cr3+, respectively. The adsorption process was endothermic, confirmed by the significantly higher adsorption capability at higher temperature. Hydroxyl, amino, and carboxyl groups were the main functional groups based on Fourier transform infrared spectroscopy analysis, and they bind to metal ions via ion exchange. The results suggest that fresh macrocolonies of N. sphaeroides can be used as an effective biosorbent for metal ion removal, especially for Pb2+ and Cr3+.
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  • AIBP-mediated cholesterol efflux instructs hematopoietic stem and progenitor cell fate

    Gu, Qilin   Yang, Xiaojie   Lv, Jie   Zhang, Jiaxiong   Xia, Bo   Kim, Jun-dae   Wang, Ruoyu   Xiong, Feng   Meng, Shu   Clements, Thomas P.   Tandon, Bhavna   Wagner, Daniel S.   Diaz, Miguel F.   Wenzel, Pamela L.   Miller, Yury I.   Traver, David   Cooke, John P.   Li, Wenbo   Zon, Leonard I.   Chen, Kaifu   Bai, Yongping   Fang, Longhou  

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  • AIBP-mediated cholesterol efflux instructs hematopoietic stem and progenitor cell fate

    Gu, Qilin   Yang, Xiaojie   Lv, Jie   Zhang, Jiaxiong   Xia, Bo   Kim, Jun-dae   Wang, Ruoyu   Xiong, Feng   Meng, Shu   Clements, Thomas P.   Tandon, Bhavna   Wagner, Daniel S.   Diaz, Miguel F.   Wenzel, Pamela L.   Miller, Yury I.   Traver, David   Cooke, John P.   Li, Wenbo   Zon, Leonard I.   Chen, Kaifu   Bai, Yongping   Fang, Longhou  

    Hypercholesterolemia, the driving force of atherosclerosis, accelerates the expansion and mobilization of hematopoietic stem and progenitor cells (HSPCs). The molecular determinants connecting hypercholesterolemia with hematopoiesis are unclear. Here, we report that a somite-derived prohematopoietic cue, AIBP, orchestrates HSPC emergence from the hemogenic endothelium, a type of specialized endothelium manifesting hematopoietic potential. Mechanistically, AIBP-mediated cholesterol efflux activates endothelial Srebp2, the master transcription factor for cholesterol biosynthesis, which in turn transactivates Notch and promotes HSPC emergence. Srebp2 inhibition impairs hypercholesterolemia-induced HSPC expansion. Srebp2 activation and Notch upregulation are associated with HSPC expansion in hypercholesterolemic human subjects. Genome-wide chromatin immunoprecipitation followed by sequencing (ChIP-seq), RNA sequencing (RNA-seq), and assay for transposase-accessible chromatin using sequencing (ATAC-seq) indicate that Srebp2 transregulates Notch pathway genes required for hematopoiesis. Our studies outline an AIBP-regulated Srebp2-dependent paradigm for HSPC emergence in development and HPSC expansion in atherosclerotic cardiovascular disease.
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