To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids...To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids were made into fungal elicitors.These fungal elicitors were added into the DE medium with concentrations of 40,60 and 80 ml/L,respectively.After a 90-d culturing,the effects of fungal elicitors on the growth of D.hybrida cultivar ‘088' tissue culture seedlings were studied.The results showed that treatment 13(T13) extremely significantly increased the fresh weight,but other treatment groups had no significant effects.In addition,T1,T5,T9,T11 and T13 extremely significantly influenced the contents of chlorophyll a and chlorophyll a + b.However,T1 and T11 had extremely significantly effect on the content of chlorophyll b.Combining the effects on fresh weight and chlorophyll content,it could be concluded T13(40 ml/L of Y05) has promoting effects on the growth of D.hybrida tissue culture seedlings.展开更多
Mycorrhizal mulberry is a plant, whose mulberry root and Arbuscular Myc-orrhizal fungi came into being a symbiotic relationship by a mean of natural or artifi-cial inoculation. Mycorrhizal mulberry coupling with main ...Mycorrhizal mulberry is a plant, whose mulberry root and Arbuscular Myc-orrhizal fungi came into being a symbiotic relationship by a mean of natural or artifi-cial inoculation. Mycorrhizal mulberry coupling with main ecological barriers, such as barren soil drought in rocky desertification area, wil be beneficial to recovering the karst degraded ecosystem by removing these stresses. So, mycorrhizal mulberry is considered a new effective way in ecological control of karst rocky desertification. The research summarized the structures and the characteristic eco-physiological functions of arbuscular mycorrhizal fungi (AMF), and preliminarily discussed its availability and research in karst rocky desertification restoration ,including investiga-tion of AMF diversity, the key affecting factor of AMF species diversity, the sym-biosis mechanism between AMF and mulberry, promoting the development of agri-cultural economy in Karst Rocky Desertification area by mycorrhizal mulberry. These elaborate efforts are to demonstrate mycorrhizal mulberry adapting to karst environ-ment from a new view, lay a theoretical basis for karst degraded-ecosystem restoration, and final y guarantee sustainable development of mycorrhizal mulberry in rocky desertification area.展开更多
The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten ...The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten the period of development. Thus the vibratory characteristics of the gyroscope is simulated with the finite element method of coupled field. The optimum exciting frequency and the factors which influence the gyroscope sensitivity are determined. The method for adjusting the frequency deviation between driving and detecting modes is also proposed.展开更多
The behavior of stress wave propagation in rock walls and the process of rock bursts were simulated by application tests of material similar to rock. Results show that 1) the attenuation characteristics of stress wave...The behavior of stress wave propagation in rock walls and the process of rock bursts were simulated by application tests of material similar to rock. Results show that 1) the attenuation characteristics of stress waves were related to the material proper-ties, stress waves attenuate more quickly in soft material and 2) when the explosion load was applied at the top of the roadway, the number and the length of the cracks increased with a decrease in the distance between the explosive point and roof of the roadway. When the distance was 280 mm, only some chips appeared near the source, when the distance was 210 mm, some small cracks started to appear near the road-rib and when the distance was reduced to 140 mm, larger cracks appeared at the road-rib. It can be concluded that, under a given stress the number of cracks is closely related to the intensity of stress waves. The cracks in the sur-rounding rock can be reduced by controlling the intensity of the stress waves and rock bursts can be avoided to some extent by pre-venting the formation of layered crack structures. A new experimental approach has been provided for studying rock bursts by using physical simulation.展开更多
Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remed...Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remediate petroleum-contaminated soils. Inlaboratory, the fungi were inoculated into a liquid Culture mediumand the petroleum-contaminated soil samples for incubation of 40 and50 days, respectively. In the 200-day pilot study, nutrient contentsand moisture were adjusted and maintained under aerobic Condition incomposting units using concrete container (118.5 cm×65.5 cm×12.5cm) designed specially For this study.展开更多
The capacities of two arbuscular mycorrhizal (AM) fungi, Glomusmosseae and Glomus versiforme, to mineralize added organic P werestudied in a sterilized clacareous soil. Mycorrhizal (inoculated witheither of the AM fun...The capacities of two arbuscular mycorrhizal (AM) fungi, Glomusmosseae and Glomus versiforme, to mineralize added organic P werestudied in a sterilized clacareous soil. Mycorrhizal (inoculated witheither of the AM fungi) and non-mycorrhizal red clover (Trifoliumpratense L.) plants were grown for eight weeks in pots with upperroot, central hyphal and lower soil compartments. The hyphal and soilcompartments received either organic P (as Na-phytte) or inorganic P(as KH_2PO_4) at the rate of 50 mg P kg^-1. No P was added to theroot compartments.展开更多
Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a...Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal (AM) fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations (10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1) of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root) of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal :olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly (p〈0.05). The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.展开更多
Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of pros...Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy (GC-MS) revealed the existence of phenol, 3, 5-bis (1, 1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas smtzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.展开更多
On 13 August 2010, a catastrophic debris flow with a volume of 1.17 million m3 occurred in Xiaojiagou Ravine near Yingxiu town of Wenchuan county in Sichuan Province, China. The main source material was the landslide ...On 13 August 2010, a catastrophic debris flow with a volume of 1.17 million m3 occurred in Xiaojiagou Ravine near Yingxiu town of Wenchuan county in Sichuan Province, China. The main source material was the landslide deposits retained in the ravine during the 2008 Wenchuan earthquake. This paper describes a two-dimensional hybrid numerical method that simulates the entire process of the debris flow from initiation to transportation and finally to deposition. The study area is discretized into a grid of square zones. A two dimensional finite difference method is then applied to simulate the rainfall-runoff and debris flow runout processes. The analysis is divided into three steps; namely, rainfall-runoff simulation, mixing water and solid materials, and debris flow runout simulation. The rainfall-runoff simulation is firstly conducted to obtain the cumulative runoff near the location of main source material and at the outlet of the first branch. The water and solid materials are then mixed to create an inflow hydrograph for the debris flow runout simulation. The occurrence time and volume of the debris flow can be estimated in this step. Finally the runout process of the debris flow is simulated. When the yield stress is high, it controls the deposition zone. When the yield stress is medium or low, both yield stress and viscosity influence the deposition zone. The flow velocity is largely influenced by the viscosity. The estimated yield stress by the equation, ty = pghsinO, and the estimated viscosity by the equation established by Bisantino et al. (2010) provide good estimates of the area of the debris flow fan and the distribution of deposition depth.展开更多
In this work, the separation of carbon dioxide (CO2) from (PSA) column was modeled and simulated. The adsorption kinetics the methane (CH4) using fixed bed Pressure Swing Adsorption on the 13X zeolite adsorbent ...In this work, the separation of carbon dioxide (CO2) from (PSA) column was modeled and simulated. The adsorption kinetics the methane (CH4) using fixed bed Pressure Swing Adsorption on the 13X zeolite adsorbent was described by Linear Driving Force (LDF) model. Simulation of adsorption phenomena inside the fixed bed was implemented using Computational Fluid Dynamic (CFD) method, based on porous media concept, and the mass transfer coefficients for gas components (COz and CH4) were developed using User Defined Scalars (UDS). The model was validated by comparing with the experimental data, which were collected based on a varied set of laboratory conditions. The prediction of the adsorption isotherm (uptake curve) and methane recovery using the simulation results exhibited a reasonable agreement with the experimental data. Moreover, the effects of feed flow rate and bed concentration evolution were investigated. The current results suggested that CFD approach is capable to predicate the hydrodynamics and adsorption phenomena in the fixed bed adsorption column.展开更多
a damage constitutive model comprising two dynamite sticks is established and handled with the transient dynamics finite element computer program PRONTO-3D to study rock damage and fragmentation during blasting. Simul...a damage constitutive model comprising two dynamite sticks is established and handled with the transient dynamics finite element computer program PRONTO-3D to study rock damage and fragmentation during blasting. Simulation tests find that tensile stress by detonation gives rise to tensile bulk strain and consequently damage in the material. Maximum bulk strain is observed in simultaneous detonations of the two dynamite sticks. It is demonstrated that the proposed method is applicable to studying the process of rock damage by blasting as well as its affecting factors.展开更多
Gr/CuCr10 alloys with graphene contents of 0.1 wt.%,0.3 wt.%,0.5 wt.%,and 0.7 wt.%were prepared by a hot pressing sintering process.Compared with CuCr10 alloy,the relative density of CuCr10 composite with 0.3 wt.%addi...Gr/CuCr10 alloys with graphene contents of 0.1 wt.%,0.3 wt.%,0.5 wt.%,and 0.7 wt.%were prepared by a hot pressing sintering process.Compared with CuCr10 alloy,the relative density of CuCr10 composite with 0.3 wt.%addition of graphene remained constant,while the electrical conductivity increased from 62.2%(IACS)to 69.5%(IACS).The main reason for the increased electrical conductivity is that the addition of graphene leads to the size reduction of Cr phase and thus reduces the scattering of electrons.In addition,Brinell’s hardness of 0.3 wt.%Gr/CuCr10 composite increased from HB 91.8 to HB 99.6 compared with that of CuCr10 alloy.The graphene was mainly distributed at the interface of Cu and Cr.A nano-Cr;C;phase,which has been observed through HRTEM,is the main reason for the wettability enhancement at the interface of Cu and Cr,thus improving the hardness of the material.展开更多
A mass transfer model in consideration of multi-layer resistances through NaA zeolite membrane and lumen pressure drop in the permeate side was developed to describe pervaporation dehydration through scaled-up hollow ...A mass transfer model in consideration of multi-layer resistances through NaA zeolite membrane and lumen pressure drop in the permeate side was developed to describe pervaporation dehydration through scaled-up hollow fiber supported NaA zeolite membrane. It was found that the transfer resistance in the lumen of the permeate side is strongly related with geometric size of hollow fiber zeolite membrane, which could not he neglected. The effect of geometric size on pervaporation dehydration could be more significant under higher vacuum pressure in the permeate side. The transfer resistance in the lumen increases with the hollow fiber length but decreases with lumen diameter. The geometric structure could be optimized in terms of the ratio of lumen diameter to membrane length. A critical value of d1/L (Rc) to achieve high permeation flux was empirically correlated with extraction pressure in the permeate side. Typically, for a hollow fiber supported NaA zeolite membrane with length of 0.40 m, the lumen diameter should be larger than 2.0 mm under the extraction pressure of 1500 Pa.展开更多
A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/s...A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.展开更多
The mercury-antimony-gold ore was subjected of the flotation. As a result of enrichment of ore, the mercury-antimony concentrate with the contents of 51.5% Sb, 3.55% Hg and 6 g/t Au was received. Vacuum distillation o...The mercury-antimony-gold ore was subjected of the flotation. As a result of enrichment of ore, the mercury-antimony concentrate with the contents of 51.5% Sb, 3.55% Hg and 6 g/t Au was received. Vacuum distillation of concentrate allocation in serial sublimates mercury and antimony was designed. The big amount gold passed to calcine after vacuum distillation. The gold in calcine roastin uo to 900 ℃was 30.6 e/t.展开更多
Through the analysis of forces acting on the waste rock in the gas solid fluidized bed, the waste rock velocity equations and displacement equations in the gas solids fluidized bed were achieved and the influential fa...Through the analysis of forces acting on the waste rock in the gas solid fluidized bed, the waste rock velocity equations and displacement equations in the gas solids fluidized bed were achieved and the influential factors of the waste rock motion in the fluidized bed were studied in this paper. The conclusions show that the primary factors influencing the waste rock motion are the waste rock grain size and the scraper velocity according to the computer simulation. This has provided the theoretical foundation both for improving the separating effect and ascertaining the length of the separating cell.展开更多
Plant phylogeny constrains orchid mycorrhizal(OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine...Plant phylogeny constrains orchid mycorrhizal(OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species,and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota(9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.展开更多
基金Supported by National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032014027)Special Fund for Agro-scientific Research in the Public Interest(201203071)Special Project for Scientific and Technological Achievements Demonstration and Promotion in Hainan Province(SQ2013CGSF0006)~~
文摘To optimize the technique of rapid propagation of Dendrobium hybrida seedlings and to explore a hormone-free tissue culture method for D.hybrida,six kinds of mycorrhizal fungi which were isolated from the wild orchids were made into fungal elicitors.These fungal elicitors were added into the DE medium with concentrations of 40,60 and 80 ml/L,respectively.After a 90-d culturing,the effects of fungal elicitors on the growth of D.hybrida cultivar ‘088' tissue culture seedlings were studied.The results showed that treatment 13(T13) extremely significantly increased the fresh weight,but other treatment groups had no significant effects.In addition,T1,T5,T9,T11 and T13 extremely significantly influenced the contents of chlorophyll a and chlorophyll a + b.However,T1 and T11 had extremely significantly effect on the content of chlorophyll b.Combining the effects on fresh weight and chlorophyll content,it could be concluded T13(40 ml/L of Y05) has promoting effects on the growth of D.hybrida tissue culture seedlings.
基金Supported by Special Foundation for Innovation Capacity Construction of Guizhou Provincial Department of Science and Technology([2012]4003)~~
文摘Mycorrhizal mulberry is a plant, whose mulberry root and Arbuscular Myc-orrhizal fungi came into being a symbiotic relationship by a mean of natural or artifi-cial inoculation. Mycorrhizal mulberry coupling with main ecological barriers, such as barren soil drought in rocky desertification area, wil be beneficial to recovering the karst degraded ecosystem by removing these stresses. So, mycorrhizal mulberry is considered a new effective way in ecological control of karst rocky desertification. The research summarized the structures and the characteristic eco-physiological functions of arbuscular mycorrhizal fungi (AMF), and preliminarily discussed its availability and research in karst rocky desertification restoration ,including investiga-tion of AMF diversity, the key affecting factor of AMF species diversity, the sym-biosis mechanism between AMF and mulberry, promoting the development of agri-cultural economy in Karst Rocky Desertification area by mycorrhizal mulberry. These elaborate efforts are to demonstrate mycorrhizal mulberry adapting to karst environ-ment from a new view, lay a theoretical basis for karst degraded-ecosystem restoration, and final y guarantee sustainable development of mycorrhizal mulberry in rocky desertification area.
文摘The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten the period of development. Thus the vibratory characteristics of the gyroscope is simulated with the finite element method of coupled field. The optimum exciting frequency and the factors which influence the gyroscope sensitivity are determined. The method for adjusting the frequency deviation between driving and detecting modes is also proposed.
基金Projects 50490270 and 50634050 supported by the National Natural Science Foundation of China2007CB209400 by the National Basic Research Program of China2006A039 by the Youth Scientific Research Foundation of China University of Mining & Technology
文摘The behavior of stress wave propagation in rock walls and the process of rock bursts were simulated by application tests of material similar to rock. Results show that 1) the attenuation characteristics of stress waves were related to the material proper-ties, stress waves attenuate more quickly in soft material and 2) when the explosion load was applied at the top of the roadway, the number and the length of the cracks increased with a decrease in the distance between the explosive point and roof of the roadway. When the distance was 280 mm, only some chips appeared near the source, when the distance was 210 mm, some small cracks started to appear near the road-rib and when the distance was reduced to 140 mm, larger cracks appeared at the road-rib. It can be concluded that, under a given stress the number of cracks is closely related to the intensity of stress waves. The cracks in the sur-rounding rock can be reduced by controlling the intensity of the stress waves and rock bursts can be avoided to some extent by pre-venting the formation of layered crack structures. A new experimental approach has been provided for studying rock bursts by using physical simulation.
基金National Natural Science Foundation of China(No.49831070) the ChineseAcademy of Sciences(No.KZ951-B1-207-01-03).
文摘Laboratory simulation studies and composting pilot study wereconducted to evaluate the capacity of three strains of fungi,indigenous fungus Fusarium sp. And Phanerochaete chrysosporium andCoriolus Versicolor, to remediate petroleum-contaminated soils. Inlaboratory, the fungi were inoculated into a liquid Culture mediumand the petroleum-contaminated soil samples for incubation of 40 and50 days, respectively. In the 200-day pilot study, nutrient contentsand moisture were adjusted and maintained under aerobic Condition incomposting units using concrete container (118.5 cm×65.5 cm×12.5cm) designed specially For this study.
基金National Key Basic Research Support Foundation (NKBRSF) of China(No. G1999011807) the Joint Open Laboratory of Soil and Environment between the Institute of Soil Science of the Chinese Academy of Sciences and Hong Kong Baptist University.
文摘The capacities of two arbuscular mycorrhizal (AM) fungi, Glomusmosseae and Glomus versiforme, to mineralize added organic P werestudied in a sterilized clacareous soil. Mycorrhizal (inoculated witheither of the AM fungi) and non-mycorrhizal red clover (Trifoliumpratense L.) plants were grown for eight weeks in pots with upperroot, central hyphal and lower soil compartments. The hyphal and soilcompartments received either organic P (as Na-phytte) or inorganic P(as KH_2PO_4) at the rate of 50 mg P kg^-1. No P was added to theroot compartments.
文摘Arsenic (As) in the soils of South-Eastern Bangladesh is not rely a threat for the health of millions of people but also a problem for plant growth due to its higher concentration in soil. Gmelina arborea Linn. is a promising fast growing tree species in Bangladesh which has dso a potential to be planted in arsenic contaminated areas. This study tssessed the role of arbuscular mycorrhizal (AM) fungi on the growth of 7. arborea in arsenic amended soils at nursery stage. Before sowing ;eeds, soils were treated with four different concentrations (10 mg.kg^-1, 25 mg.kg^-1, 50 mg.kg^-1, and 100 mg.kg^-1) of Arsenic. Growth parameters length of shoot and root, collar diameter, fresh and dry weight of shoot and root) of the plant, and mycorrhizal root colonization and spore population in the rhizosphere soil of G. arborea were recorded. Mycorrhizal seedlings showed better growth than non-mycorrhizal eedlings. Myeorrhizal seedlings planted in soil with 10-mg.kg^-1 arsenic howed best performance in terms of growth, biomass and mycorrhizal :olonization, compared to other treatments with higher concentration of Lrsenie. With increasing arsenic concentration, growth of seedlings, nycorrhizal infection rate and spore population, all decreased ignificantly (p〈0.05). The mycorrhizal seedlings had as much as 40% higher increment in total growth and 2.4 times higher increment in biomass compared to non-mycorrhizal seedlings. The study clearly indicated that mycorrhizal inoculation could reduce the harmful effects of arsenic on the initial growth of G. arborea Linn. in degraded soil at nursery stage.
文摘Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy (GC-MS) revealed the existence of phenol, 3, 5-bis (1, 1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas smtzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.
基金support from Sichuan Provincial Department of Transportation and Communications,the National Basic Research Program of China (Grant No.2011CB013506)the Research Grants Council of the Hong Kong SAR (Grant No.622210)
文摘On 13 August 2010, a catastrophic debris flow with a volume of 1.17 million m3 occurred in Xiaojiagou Ravine near Yingxiu town of Wenchuan county in Sichuan Province, China. The main source material was the landslide deposits retained in the ravine during the 2008 Wenchuan earthquake. This paper describes a two-dimensional hybrid numerical method that simulates the entire process of the debris flow from initiation to transportation and finally to deposition. The study area is discretized into a grid of square zones. A two dimensional finite difference method is then applied to simulate the rainfall-runoff and debris flow runout processes. The analysis is divided into three steps; namely, rainfall-runoff simulation, mixing water and solid materials, and debris flow runout simulation. The rainfall-runoff simulation is firstly conducted to obtain the cumulative runoff near the location of main source material and at the outlet of the first branch. The water and solid materials are then mixed to create an inflow hydrograph for the debris flow runout simulation. The occurrence time and volume of the debris flow can be estimated in this step. Finally the runout process of the debris flow is simulated. When the yield stress is high, it controls the deposition zone. When the yield stress is medium or low, both yield stress and viscosity influence the deposition zone. The flow velocity is largely influenced by the viscosity. The estimated yield stress by the equation, ty = pghsinO, and the estimated viscosity by the equation established by Bisantino et al. (2010) provide good estimates of the area of the debris flow fan and the distribution of deposition depth.
文摘In this work, the separation of carbon dioxide (CO2) from (PSA) column was modeled and simulated. The adsorption kinetics the methane (CH4) using fixed bed Pressure Swing Adsorption on the 13X zeolite adsorbent was described by Linear Driving Force (LDF) model. Simulation of adsorption phenomena inside the fixed bed was implemented using Computational Fluid Dynamic (CFD) method, based on porous media concept, and the mass transfer coefficients for gas components (COz and CH4) were developed using User Defined Scalars (UDS). The model was validated by comparing with the experimental data, which were collected based on a varied set of laboratory conditions. The prediction of the adsorption isotherm (uptake curve) and methane recovery using the simulation results exhibited a reasonable agreement with the experimental data. Moreover, the effects of feed flow rate and bed concentration evolution were investigated. The current results suggested that CFD approach is capable to predicate the hydrodynamics and adsorption phenomena in the fixed bed adsorption column.
基金Chongqing Yudong Freeway Engineering Co.Ltd. (SJ-43-0106191)Chongqing Traffic Committee ([2002]23-3#) and Henan Province Preeminent Youth Foundation (0310053100).
文摘a damage constitutive model comprising two dynamite sticks is established and handled with the transient dynamics finite element computer program PRONTO-3D to study rock damage and fragmentation during blasting. Simulation tests find that tensile stress by detonation gives rise to tensile bulk strain and consequently damage in the material. Maximum bulk strain is observed in simultaneous detonations of the two dynamite sticks. It is demonstrated that the proposed method is applicable to studying the process of rock damage by blasting as well as its affecting factors.
基金financially supported by the National Natural Science Foundation of China(No.51871111)Jinan Changan Graphene Aluminum Material Technology Co.,Ltd.,Chinathe Dingmei New Material Technology Co.,Ltd.,China。
文摘Gr/CuCr10 alloys with graphene contents of 0.1 wt.%,0.3 wt.%,0.5 wt.%,and 0.7 wt.%were prepared by a hot pressing sintering process.Compared with CuCr10 alloy,the relative density of CuCr10 composite with 0.3 wt.%addition of graphene remained constant,while the electrical conductivity increased from 62.2%(IACS)to 69.5%(IACS).The main reason for the increased electrical conductivity is that the addition of graphene leads to the size reduction of Cr phase and thus reduces the scattering of electrons.In addition,Brinell’s hardness of 0.3 wt.%Gr/CuCr10 composite increased from HB 91.8 to HB 99.6 compared with that of CuCr10 alloy.The graphene was mainly distributed at the interface of Cu and Cr.A nano-Cr;C;phase,which has been observed through HRTEM,is the main reason for the wettability enhancement at the interface of Cu and Cr,thus improving the hardness of the material.
基金Supported by the National Natural Science Foundation of China(21490585 and21776128)the National High-tech R&D Program of China(2015AA03A602)+1 种基金the"Six Top Talents"and"333 Talent Project"of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A mass transfer model in consideration of multi-layer resistances through NaA zeolite membrane and lumen pressure drop in the permeate side was developed to describe pervaporation dehydration through scaled-up hollow fiber supported NaA zeolite membrane. It was found that the transfer resistance in the lumen of the permeate side is strongly related with geometric size of hollow fiber zeolite membrane, which could not he neglected. The effect of geometric size on pervaporation dehydration could be more significant under higher vacuum pressure in the permeate side. The transfer resistance in the lumen increases with the hollow fiber length but decreases with lumen diameter. The geometric structure could be optimized in terms of the ratio of lumen diameter to membrane length. A critical value of d1/L (Rc) to achieve high permeation flux was empirically correlated with extraction pressure in the permeate side. Typically, for a hollow fiber supported NaA zeolite membrane with length of 0.40 m, the lumen diameter should be larger than 2.0 mm under the extraction pressure of 1500 Pa.
基金Projects(41172276,51279155)supported by the National Natural Science Foundation of ChinaProjects(106-00X101,106-5X1205)supported by the Central Financial Funds for the Development of Characteristic Key Disciplines in Local University,China
文摘A series of numerical simulations of conventional and true triaxial tests for soft rock materials using the three-dimensional finite difference code FLAC3D were presented. A hexahedral element and a strain hardening/softening constitutive model based on the unified strength theory(UST) were used to simulate both the consolidated-undrained(CU) triaxial and the consolidated-drained(CD) true triaxial tests. Based on the results of the true triaxial tests simulation, the effect of the intermediate principal stress on the strength of soft rock was investigated. Finally, an example of an axial compression test for a hard rock pillar with a soft rock interlayer was analyzed using the two-dimensional finite difference code FLAC. The CD true triaxial test simulations for diatomaceous soft rock suggest the peak and residual strengths increase by 30% when the effect of the intermediate principal stress is taken into account. The axial compression for a rock pillar indicated the peak and residual strengths increase six-fold when the soft rock interlayer approached the vertical and the effect of the intermediate principal stress is taken into account.
文摘The mercury-antimony-gold ore was subjected of the flotation. As a result of enrichment of ore, the mercury-antimony concentrate with the contents of 51.5% Sb, 3.55% Hg and 6 g/t Au was received. Vacuum distillation of concentrate allocation in serial sublimates mercury and antimony was designed. The big amount gold passed to calcine after vacuum distillation. The gold in calcine roastin uo to 900 ℃was 30.6 e/t.
文摘Through the analysis of forces acting on the waste rock in the gas solid fluidized bed, the waste rock velocity equations and displacement equations in the gas solids fluidized bed were achieved and the influential factors of the waste rock motion in the fluidized bed were studied in this paper. The conclusions show that the primary factors influencing the waste rock motion are the waste rock grain size and the scraper velocity according to the computer simulation. This has provided the theoretical foundation both for improving the separating effect and ascertaining the length of the separating cell.
基金supported by the National Natural Sciences Foundation of China (81274197)
文摘Plant phylogeny constrains orchid mycorrhizal(OrM) fungal community composition in some orchids. Here, we investigated the structures of the OrM fungal communities of eight Dendrobium species in one niche to determine whether similarities in the OrM fungal communities correlated with the phylogeny of the host plants and whether the Dendrobium-OrM fungal interactions are phylogenetically conserved. A phylogeny based on DNA data was constructed for the eight coexisting Dendrobium species,and the OrM fungal communities were characterized by their roots. There were 31 different fungal lineages associated with the eight Dendrobium species. In total, 82.98% of the identified associations belonging to Tulasnellaceae, and a smaller proportion involved members of the unknown Basidiomycota(9.67%). Community analyses revealed that phylogenetically related Dendrobium tended to interact with a similar set of Tulasnellaceae fungi. The interactions between Dendrobium and Tulasnellaceae fungi were significantly influenced by the phylogenetic relationships among the Dendrobium species. Our results provide evidence that the mycorrhizal specificity in the eight coexisting Dendrobium species was phylogenetically conserved.