Wyniki wyszukiwania - Biblioteka Nauki

1

Desulfurization and denitrification technologies of coal-fired flue gas

100%

Cheng G. , Zhang C.

Polish Journal of Environmental Studies

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2018

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tom 27

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nr 2

EN

Coal, as one of the most important sources of energy around the world due to the intensity of its exploiting and utilization, causes increasingly serious ecological problems, especially air pollution. Large amounts of pollutants are emitted during coal combustion, with NOx and SO₂ being the principal compositions. Therefore, desulfurization and denitrification are extremely urgent. Many technologies have been developed and applied. Our paper introduces mature and new flue gas denitration and desulfurization technologies along with their processing principles, industrial status, merits, and demerits. The combination of SNCR and SCR technology avoids their respective shortcomings and improves denitrification efficiency and economy. Based on the present situation, future trends are put forward. Synergetic, effective, and cheap desulfurization and denitration technologies will be our focus.

2

Surface modification of nano-TiN by using silane coupling agent

80%

Cheng G. , Luo J. , Qian J. , Miao J.

Materials Science Poland

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2014

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tom Vol. 32, No. 2

214--219

EN

Titanium nitride (TiN) nano-particles were subjected to graft modification by silane coupling agent (KH-570) via a direct blending method. The hydroxyl groups on the surface of TiN nano-particles can interact with silanol groups [–Si–OCH3] of KH-570 forming an organic coating layer. The covalent bonds (Ti–O–Si) formation was testified by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). Through transmission electron micrograph (TEM) observations, it was found that KH-570 could improve the dispersibility of nano-TiN particles in ethyl acetate. Thermo gravimetric analysis (TGA) and contact angle measurements indicated that KH-570 molecules were adsorbed or anchored on the surface of nano-TiN particle and the net efficiency of it was 22.76 %, which facilitated to hinder the aggregation of nano-TiN particles.

3

Soil respiration in response to a short-term nitrogen addition in an alpine steppe of Northern Tibet

80%

Sun J. , Cheng G. , Fan J.

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tom 61

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nr 4

EN

Northern Tibet has a vital role in global ecological security. This study determined the effect of environmental factors on the soil respiration of an alpine steppe. Short-term nitrogen addition (2 g N m⁻² yr⁻¹) was performed in an alpine steppe in Northern Tibet in June, 2011. Soil respiration was observed during the growing season of 2011 using LI-8100. The results were as follows. First, soil respiration had clear seasonal patterns, and significant differences existed between the control (CK) and nitrogen addition (ND) treatments (P = 0.004). Second, soil respiration was more sensitive to soil temperature (R² = 0.988, ND; R² = 0.05, CK) than soil moisture (R² = 0.0003, ND; R² = 0.038, CK), and the relationship between soil temperature and soil respiration in ND treatment was more significant than that in CK. Third, the relationships between soil chemical properties and root biomass in CK were greater than that in ND plots, especially the relationship of root biomass with the available nitrogen and nitrate nitrogen. These results indicated that differences among geographical conditions resulted in different phenomena of gas emissions, immature soil, and extremely short plant growing time, which may all be remarkably influenced in an alpine steppe.

4

Nitration of Toluene and Chlorobenzene with HNO3/Ac2O Catalyzed by Caprolactam-based Bronsted Acidic Ionic Liquids

80%

Ql X. , Cheng G. , Lu C. , Qian D.

Central European Journal of Energetic Materials

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2007

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tom Vol. 4, nr 3

105-113

EN

Several new caprolactam-based Bronsted acidic ionic liquids [Caprolactam]X (X- = pTSO-, BSO-, BF4-, NO3-) with relatively lower cost and lower toxicity were synthesized and for the first time used in catalyzing organic reaction. They showed good catalytic activity in the nitration of toluene and chlorobenzene with HNO3/Ac2O under mild conditions. Among them, [Caprolactam]pTSO was the best one probably because of its better affinity to aromatics than the others. [Caprolactam]pTSO catalyzed the nitration of toluene with achieving a high yield (99.7%, calculated by quantitative GC) and better para-selectivity (ortho/para=1.03) than the traditional mixed acid methodology. And the catalyst can be recycled for four times.

5

Selective Nitration of Chlorobenzene on Super-acidic Metal Oxides

80%

Cheng G. , Ql X. , Lu C.

Central European Journal of Energetic Materials

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2007

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tom Vol. 4, nr 4

59-65

EN

The solid catalysts of SO4 2-/TiO2, SO4 2-/TiO2-ZrO2, SO4 2-/WO3-ZrO2, and SO4 2-/MoO3-ZrO2 have been prepared and regioselectiveties of chlorobenzene minonitration on these catalysts were investigated. When the reaction was carried out at 30 C for 30 min, SO4 2-/TiO2-ZrO2(1:1) by a calcination step for 3 h at 550 C enhanced the para-selectivity of chlorobenzene nitration by using nitric acid as nitrating agent, up to an ortho-para isomer ratio 0.17 in product distribution of chlorobenzene mono- nitration, and the yield of chlorobenzene mononitration was 55%. The catalysts could be reutilized for four times with a little decrease in activity.

6

Soil respiration in response to a short-term nitrogen addition in an alpine steppe of Northern Tibet

80%

Sun J. , Cheng G. , Fan J.

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2013

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tom Vol. 61, nr 4

655--663

EN

Northern Tibet has a vital role in global ecological security. This study determined the effect of environmental factors on the soil respiration of an alpine steppe. Short-term nitrogen addition (2 g N m-2 yr-1) was performed in an alpine steppe in Northern Tibet in June, 2011. Soil respiration was observed during the growing season of 2011 using LI-8100. The results were as follows. First, soil respiration had clear seasonal patterns, and significant differences existed between the control (CK) and nitrogen addition (ND) treatments (P = 0.004). Second, soil respiration was more sensitive to soil temperature (R2 = 0.988, ND; R2 = 0.05, CK) than soil moisture (R2 = 0.0003, ND; R2 = 0.038, CK), and the relationship between soil temperature and soil respiration in ND treatment was more significant than that in CK. Third, the relationships between soil chemical properties and root biomass in CK were greater than that in ND plots, especially the relationship of root biomass with the available nitrogen and nitrate nitrogen. These results indicated that differences among geographical conditions resulted in different phenomena of gas emissions, immature soil, and extremely short plant growing time, which may all be remarkably influenced in an alpine steppe.

7

Energy feature of a multi-flow column flotation process

71%

Cheng G. , Yu Y. , Ma L. , Xia W. , Xu H.

Physicochemical Problems of Mineral Processing

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2017

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tom Vol. 53, iss. 2

1266--1284

EN

A cyclonic-static micro-bubble flotation column (FCSMC) has been widely used in mineral separation. FCSMC includes countercurrent, cyclone and jet flow mineralization zones in a single column. In this study, the energy feature of the three different zones was compared. The turbulent flow was evaluated in terms of the turbulent kinetic energy (k) and the turbulent dissipation rate (ε). An appropriate computing model was determined by comparing the flow field value measured by PIV with the results of the Fluent numerical simulation. Jet flow separation exhibited the maximum k and ε values among the three columns, whereas counter-current separation displayed the minimum values. The high circulating volumetric flowrate means great energy input and turbulent intensity. The higher turbulent dissipation rate, the smaller the bubble is. The better performance of the FCSMC was mainly attributed to the multiple mineralization steps. The floatability of mineral particles gradually decreases with an increase in flotation time, the mineralization energy gradually increased to overcome the decrease in mineral floatability. By contrast, the countercurrent was beneficial for recovering the coarse particles, and the jet flow was beneficial for recovering the fine particles.

8

Reduced ghrelin in endothelial cells plays important mechanistic role in aging-related impairment of angiogenesis

71%

Ahluwalia A. , li A. , Cheng G. , Deng X. , Tarnawski A. S.

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nr 2

29-34

EN

Ghrelin, a hormone produced mainly by gastric mucosal cells stimulates growth hormone (GH) release. Ghrelin is also expressed in the endothelial cells of blood vessels suggesting its physiological role and a function in these cells. We recently demonstrated that ghrelin induces angiogenesis - new capillary blood vessel formation- in neonatal human microvascular endothelial cells (HMVECs). Angiogenesis is impaired in aging individuals both in vitro and in vivo, but the precise mechanism(s) of this phenomenon is unknown. We examined whether HMVECs derived from aging individuals (66 years and 90 years old), 66-HMVECs and 90-HMVECs have reduced ghrelin levels vs. neonatal (Neo) HMVECs and whether treatment with exogenous ghrelin can restore impaired in vitro angiogenesis on matrigel in aged HMVECs. Ghrelin levels were reduced in the aged HMVECs by 3.2-fold (p<0.05) compared to Neo-HMVECs. Angiogenesis was significantly decreased in the aged 66- and 90-HMVECs by 39.7% (p = 0.003) and 62.4% (p = 0.003), respectively compared to Neo-HMVECs. Treatment with exogenous ghrelin significantly reversed impaired angiogenesis in aged HMVECs with the EC50 0.05 nM. Ghrelin induced angiogenesis in Neo-HMVECs mainly through ERK2 activation. This study is the first demonstration that reduced ghrelin is one of the factors responsible for aging-related impairment of angiogenesis.

9

Effect of hydroxyl radical on the scission of cellular wall polysaccharides in vitro of banana fruit at various ripening stages

61%

Cheng G. , Duan X. , Yang B. , Jiang Y. , Lu W. , Luo Y. , Jiang W.

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nr 2

EN

Fruit ripening is generally attributed to disassembly of cellular wall, particularly due to solubilisation and depolymerisation of pectin and hemicellulose. Experiments were conducted to test effects of hydroxyl radicals (OH) on the scission of cellular wall polysaccharides from pulp tissues of banana fruit at different ripening stage. Cellular wall materials were isolated from pulp tissues of banana fruit at different ripening stages. Two pectic fractions, water soluble pectin (WSP) and acid soluble pectin (ASP), and two hemicellulosic fractions, 1 M KOH soluble hemicellulose (HC1) and 4 M KOH soluble hemicellulos (HC2), were obtained from the cellular wall materials from pulp tissues, respectively. Effects of OH induced by the Fenton reaction on the scission of pectin and hemicellulose in vitro were investigated. As fruit ripening progressed, the sugar components of the WSP, HC1 and HC2 attacked by OH showed obvious molecular-mass downshifts. Thus, OH caused the disassembly of polysaccharides (WSP, ASP, HC1 and HC2) from cellular walls of pulp tissues of banana fruit, demonstrated by the reduced molecular mass distribution. Moreover, OH production in pulp tissues increased significantly as banana fruit ripened, which further help account for the role of OH in accelerated fruit ripening.

10

A study of bubble-particle interactions in a column flotation process

61%

Cheng G. , Shi C. , Yan X. , Zhang Z. , Xu H. , Lu Y.

Physicochemical Problems of Mineral Processing

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2017

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tom Vol. 53, iss. 1

17--33

EN

Bubble-particle interactions play an important role in flotation. This study examines the behaviour of bubble clusters in a turbulent flotation cell. Particularly, the bubble-particle interaction characteristics in flotation are investigated. The bubble size in a flotation column was measured using an Olympus i-SPEED 3 high-speed camera. Relationships between the circulating volume, bubble size and bubble terminal velocity were discussed. Probabilities of collision, attachment, detachment and acquisition between bubbles and particles in different circulating volumes were calculated based on the flotation kinetic theory. Using the extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theory, the relationship between the potential energy and distance in bubble-particle interaction was analysed. The results demonstrated that as the circulating volume increased, the bubble size and velocity decreased. When the circulating volume increased from 0.253 to 0.495 m3/h, the bubble diameter decreased from 511 to 462 μm, and the corresponding bubble velocity decreased from 43.1 to 37.5 mm/s. When the circulating volume remained constant as the particle size increased, probabilities of collision, attachment, detachment and acquisition increased. When the particle size remained constant as the circulating volume increased, these probabilities also increased. At a constant circulating volume as the particle size increased, the absolute value of the total potential energy between the particle and bubble increased. When the distance between the bubble and particle was 30 nm, the energy barrier appeared.

11

A Fast Method of Feature Extraction for Lowering Vehicle Pass-By Noise Based on Nonnegative Tucker3 Decomposition

61%

Wang H. , Cheng G. , Deng G. , Li X. , Li H. , Huang Y.

Archives of Acoustics

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2017

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tom Vol. 42, No. 4

619--629

EN

Usually, the judgement of one type fault of vehicle pass-by noise is difficult for engineers, especially when some significant features are disturbed by other interference noise, such as the squealing noise is almost simultaneous with the whistle in the exhaust system. In order to cope with this problem, a new method, with the antinoise ability of the algorithm on the condition by which the features are entangled, is developed to extract clear features for the fault analysis. In the proposed method, the nonnegative Tucker3 decomposition (NTD) with fast updating algorithm, signed as NTD_FUP, can find out the natural frequency of the parts/components from the exhaust system. Not only does the NTD_FUP extract clear features from the confused noise, but also it is superior to the traditional methods in practice. Then, an aluminium-foil alloy material, which is used for the heat shield for its lower noise radiation, replaces the aluminium alloy alone. Extensive experiments show that the sound pressure level of the vehicle pass-by noise is reduced 0.9 dB(A) by the improved heat shield, which is also considered as a more lightweight design for the exhaust system of an automobile.

12

Analysis of the influence of the transducer and its coupling layer on round window stimulation

61%

Liu H. , Xu D. , Yang J. , Yang S. , Cheng G. , Huang X.

Acta of Bioengineering and Biomechanics

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2017

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tom Vol. 19, no. 2

103--111

EN

Purpose: In this work, a finite element study is proposed to evaluate the effects of the transducer and its coupling layer on the performance of round window (RW) stimulation. Methods: Based on a set of micro-computer tomography images of a healthy adult’s right ear and reverse engineering technique, a coupled finite-element model of the human ear and the transducer was constructed and verified. Then, the effect of the cross-section of the transducer, the elastic modulus of the coupling layer, the mass of the transducer, and the preload of the transducer were studied. Results: The increase of the transducer’s cross-section area deteriorates the RW stimulation, especially at the lower frequencies. This adverse effect of the cross-section area’s increase of the transducer can be reduced by adding a coupling layer between the transducer and the RW. However, the coupling layer’s improvement on the RW stimulation is reduced with the increase of its elastic modulus. Moreover, the mass loading of the transducer decreases the RW stimulation’s performance mainly at higher frequencies and applying a static preload on the transducer enhances its hearing compensating performance at higher frequencies. Conclusions: The influence of the transducer’s mass, the mass of the transducer, the applied static preload and the properties of the coupling layer must be taken into account in the design of the RW stimulation type implantable middle ear hearing device.

13

Polyamine plays a role in subculture growth of in vitro callus of indica rice

51%

Tan Y. , Hu W. , Xu X. , Zhou J. , Wang C. , Liu X. , Cheng G.

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