TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface w...TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B（Rh B）was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction（XRD）, N2 adsorption/desorption measurements, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and diffuse reflectance spectroscopy（DRS）. The photodegradation efficiencies of the two films were studied by Rh B removal in water under UV（ultraviolet） irradiation. Over 4 day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.展开更多
The interaction between the airflow and train influences the aerodynamic characteristics and dynamic performance of high-speed trains.This study focused on the fluid-solid coupling effect of airflow and HST,and propos...The interaction between the airflow and train influences the aerodynamic characteristics and dynamic performance of high-speed trains.This study focused on the fluid-solid coupling effect of airflow and HST,and proposed a co-simulation(CS)approach between computational fluid dynamics and multi-body dynamics.Firstly,the aerodynamic model was developed by employing overset mesh technology and the finite volume method,and the detailed train-track coupled dynamic model was established.Then the User Data Protocol was adopted to build data communication channels.Moreover,the proposed CS method was validated by comparison with a reported field test result.Finally,a case study of the HST exiting a tunnel subjected to crosswind was conducted to compare differences between CS and offline simulation(OS)methods.In terms of the presented case,the changing trends of aerodynamic forces and car-body displacements calculated by the two methods were similar.Differences mainly lie in aerodynamic moments and transient wheel-rail impacts.Maximum pitching and yawing moments on the head vehicle in the two methods differ by 21.1 kN∙m and 29.6 kN∙m,respectively.And wheel-rail impacts caused by sudden changes in aerodynamic loads are significantly severer in CS.Wheel-rail safety indices obtained by CS are slightly greater than those by OS.This research proposes a CS method for aerodynamic characteristics and dynamic performance of the HST in complex scenarios,which has superiority in computational efficiency and stability.展开更多
In the H2SO4 medium and in the presence of dodecylbenzene sulfonic acid sodiumsalt (DBS), dimethyl yellow (R) could emit strong and stable solid substrate room temperature phosphorescence (RTP) on filter paper. And Na...In the H2SO4 medium and in the presence of dodecylbenzene sulfonic acid sodiumsalt (DBS), dimethyl yellow (R) could emit strong and stable solid substrate room temperature phosphorescence (RTP) on filter paper. And NaIO4 could oxidize R to cause the RTP quenching. Arsenic(V) could catalyze the reaction of NaIO4 oxidizing R, which caused the RTP sharply quenching. The reducing value of phosphorescence intensity (ΔIp) for the system with DBS is 3.3 times higher than that without DBS. Moreover, the ΔIp is proportional to the concentration of As(V). Based on the facts above, a new RTP quenching method for the determination of trace As(V) has been established.展开更多
A mathematical model of an amperometric biosensor with the substrate inhibition for steady-state condition is discussed. The model is based on the system of non-stationary diffusion equation containing a non-linear te...A mathematical model of an amperometric biosensor with the substrate inhibition for steady-state condition is discussed. The model is based on the system of non-stationary diffusion equation containing a non-linear term related to non-Michaelis–Menten kinetics of the enzymatic reaction. This paper presents the analytical expression of concentrations and current for all values of parameters φ2s φ2s α and β . Here the Adomian decomposition method (ADM) is used to find the analytical expressions for substrate, product concentration and current. A comparison of the analytical approximation and numerical simulation is also presented. A good agreement between theoretical predictions and numerical results is observed.展开更多
In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fun...In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fungi with sufficient cellulose, hemicellulose and lignin and a small amount of nitrogen, phosphorus, potassium, calcium, magnesium, other mineral salts, and some vitamins for the growth of edible fungi. However, the Pinus massoniana wood contained a significant amount of terpenoids, which are detrimental to the growth of edible fungus and mycelial. The major and current detoxification methods for Pinus massoniana sawdust were analyzed, such as steaming method, distillation method, lime water immersion method, outdoor piling fermentation method, and chemical method. Their advantages and disadvantages were discussed and reviewed. Finally, the major issues in the application of Pinus massoniana sawdust as the cultivation substrate of edible fungi were analyzed, and the application prospect of Pinus massoniana sawdust as the substrate for the cultivation of edible fungi was also reviewed.展开更多
Well-aligned hexagonal ZnO nanotubes （NTs） arrays were synthesized on pretreated indium tin oxide （ITO） substrates by a simple hydro- thermal method. The morphology and structure of the products were characterized...Well-aligned hexagonal ZnO nanotubes （NTs） arrays were synthesized on pretreated indium tin oxide （ITO） substrates by a simple hydro- thermal method. The morphology and structure of the products were characterized by scanning electron microscopy （SEM） and X-ray diffraction analysis （XRD）. A new method of substrate pretreatment was introduced to prepare ZnO coated films. The size of ZnO seeds and the formation rate of ZnO NTs were investigated. Further, the mechanism of the preparation of ZnO NTs was discussed. The photoluminescence （PL） spectrum measurement shows fairly internal defects existing in ZnO nanotubes.展开更多
Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formati...Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.展开更多
The paper investigates continuously changing wrinkle patterns of thin films bonded to a gradient substrate. Three types of gradient substrates including exponential, power-law, and symmetry models are considered. The ...The paper investigates continuously changing wrinkle patterns of thin films bonded to a gradient substrate. Three types of gradient substrates including exponential, power-law, and symmetry models are considered. The Galerkin method is used to dis- cretize the governing equation of film bonded to gradient substrates. The wavelength and the normalized amplitude of the wrinkles for substrates of various material gradients are obtained. The numerical simulation based on the finite element method （FEM） is used to evolve the wrinkle patterns. The result agrees well with that of the analytical model. It is concluded that localization of wrinkle patterns strongly depends on the material gradient. The critical membrane force depends on both the minimum value of wrinkle stiffness and the gradient of wrinkle stiffness when the wrinkle stiffness is at its minimum. This work provides a better understanding for local wrinkle formation caused by gradient substrates.展开更多
Large-scale growth of copper oxide nanowires was realized on surfaces of various copper-containing substrates, including copper grids, high-purity copper foils, and small copper blocks, by the stress-induced method. A...Large-scale growth of copper oxide nanowires was realized on surfaces of various copper-containing substrates, including copper grids, high-purity copper foils, and small copper blocks, by the stress-induced method. A relatively low heating temperature of 340 ~C was demonstrated to give rise to dense nanowire growth with fine crystal structures and high aspect ratio of approximately 300. Gradual cooling process, which is positive for the growth of nanowires on multi-layer substrates, is shown to have no effect on the nanowire growth on other pure copper substrates. Diameter of as-obtained nanowires is mainly dependent on the heating temperature. Moreover, the nanowires growing on copper grids are much longer than those growing on two other substrates.展开更多
A two-dimensional kinetic Monte-Carlo(KMC) method was used to approach the thickness distribution of large scale metallic sheet deposited by electron beam physical vapor deposition(EB-PVD) on rotating substrate. The K...A two-dimensional kinetic Monte-Carlo(KMC) method was used to approach the thickness distribution of large scale metallic sheet deposited by electron beam physical vapor deposition(EB-PVD) on rotating substrate. The KMC model involves incident atom attachment, adatom diffusion and adatom detachment. The effective deposition rate and effective incident angle along substrate radial were studied as influencing factors of sheet thickness distribution. The KMC simulation results indicate that incident angle is a very important factor to affect the sheet thickness distribution as well as theory deposition mass. The experiments results show that the KMC model can predict the thickness distribution of large scale sheet deposited by EB-PVD on rotating substrate.展开更多
[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substr...[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substrate to water and leaching time for the detection of nutrient contents in the substrate by a soil nutrient measuring instrument were discussed firstly, and then the results of nutrient contents measured by the soil nutrient measuring instrument were compared with that by conventional approaches. [ Result] In compadson with the conventional methods, the av- erage content of available nitrogen measured by the soil nutrient measuring instrument was slightly higher, while the average content of available phosphorus measured by the instrument was lower; the average content of available potassium measured by the instrument was close to that by the conventional method. [ Conclusion] This study could provide us a new method to detect available nitrogen, phosphorus and potassium content in seedling substrate efficiently.展开更多
The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating s...The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.展开更多
In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, t...In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, then, on the concentration and temperature profiles by simulating the process in a tubular reactor, varying the enzyme concentration and the reactant mixture velocity. The transport phenomena considered during the enzymatic hydrolysis process have been described by means of unsteady-state momentum, mass and energy balance equations, taking into account molecular and convective transport and generation terms. Interpretation and discussion of the results obtained by FEM resolution of PDEs involved allow to understand the relevance of the operating parameters.展开更多
Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further p...Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.展开更多
In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(...In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(FDTD)method.The proposed structure has the hexagonal close packed of 16×20 circular rods that are suspended in the air substrate with a lattice constant of 606 nm.The plane wave expansion(PWE)method is used to obtain the band diagram for AODFF at an operating wavelength of 1550 nm.The proposed optical flip-flop achieves a low delay time of 0.2 ps and a high contrast ratio(CR)of 10.33 dB.The main advantage of this design is that the input power as low as 1 mW/μm^(2) is sufficient for its operation,since no nonlinear rods are included.In addition,the footprint of the proposed AODFF is 100μm^(2),which is smaller compared to the structures reported in the literature,and it has a fast switching frequency of 5 Tbit/s.展开更多
基金supported by the National Science Funds for Creative Research Groups of China (No. 51421006)the National Major Projects of Water Pollution Control and Management Technology (No. 2017ZX07204003)+2 种基金the National Key Plan for Research and Development of China (2016YFC0502203)the Key Program of National Natural Science Foundation of China (No. 91647206)the Qing Lan Project of Jiangsu Province, and PAPD
文摘TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B（Rh B）was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction（XRD）, N2 adsorption/desorption measurements, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and diffuse reflectance spectroscopy（DRS）. The photodegradation efficiencies of the two films were studied by Rh B removal in water under UV（ultraviolet） irradiation. Over 4 day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.
基金Supported by the Sichuan Science and Technology Program(Grant No.2023ZDZX0008)the National Natural Science Foundation of China(Grant No.52388102)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘The interaction between the airflow and train influences the aerodynamic characteristics and dynamic performance of high-speed trains.This study focused on the fluid-solid coupling effect of airflow and HST,and proposed a co-simulation(CS)approach between computational fluid dynamics and multi-body dynamics.Firstly,the aerodynamic model was developed by employing overset mesh technology and the finite volume method,and the detailed train-track coupled dynamic model was established.Then the User Data Protocol was adopted to build data communication channels.Moreover,the proposed CS method was validated by comparison with a reported field test result.Finally,a case study of the HST exiting a tunnel subjected to crosswind was conducted to compare differences between CS and offline simulation(OS)methods.In terms of the presented case,the changing trends of aerodynamic forces and car-body displacements calculated by the two methods were similar.Differences mainly lie in aerodynamic moments and transient wheel-rail impacts.Maximum pitching and yawing moments on the head vehicle in the two methods differ by 21.1 kN∙m and 29.6 kN∙m,respectively.And wheel-rail impacts caused by sudden changes in aerodynamic loads are significantly severer in CS.Wheel-rail safety indices obtained by CS are slightly greater than those by OS.This research proposes a CS method for aerodynamic characteristics and dynamic performance of the HST in complex scenarios,which has superiority in computational efficiency and stability.
文摘In the H2SO4 medium and in the presence of dodecylbenzene sulfonic acid sodiumsalt (DBS), dimethyl yellow (R) could emit strong and stable solid substrate room temperature phosphorescence (RTP) on filter paper. And NaIO4 could oxidize R to cause the RTP quenching. Arsenic(V) could catalyze the reaction of NaIO4 oxidizing R, which caused the RTP sharply quenching. The reducing value of phosphorescence intensity (ΔIp) for the system with DBS is 3.3 times higher than that without DBS. Moreover, the ΔIp is proportional to the concentration of As(V). Based on the facts above, a new RTP quenching method for the determination of trace As(V) has been established.
文摘A mathematical model of an amperometric biosensor with the substrate inhibition for steady-state condition is discussed. The model is based on the system of non-stationary diffusion equation containing a non-linear term related to non-Michaelis–Menten kinetics of the enzymatic reaction. This paper presents the analytical expression of concentrations and current for all values of parameters φ2s φ2s α and β . Here the Adomian decomposition method (ADM) is used to find the analytical expressions for substrate, product concentration and current. A comparison of the analytical approximation and numerical simulation is also presented. A good agreement between theoretical predictions and numerical results is observed.
文摘In this paper, the research status of using Pinus massoniana sawdust for the cultivation of edible fungi was analyzed and discussed. It was found that Pinus massoniana sawdust contained the material base of edible fungi with sufficient cellulose, hemicellulose and lignin and a small amount of nitrogen, phosphorus, potassium, calcium, magnesium, other mineral salts, and some vitamins for the growth of edible fungi. However, the Pinus massoniana wood contained a significant amount of terpenoids, which are detrimental to the growth of edible fungus and mycelial. The major and current detoxification methods for Pinus massoniana sawdust were analyzed, such as steaming method, distillation method, lime water immersion method, outdoor piling fermentation method, and chemical method. Their advantages and disadvantages were discussed and reviewed. Finally, the major issues in the application of Pinus massoniana sawdust as the cultivation substrate of edible fungi were analyzed, and the application prospect of Pinus massoniana sawdust as the substrate for the cultivation of edible fungi was also reviewed.
基金supported by the National Basic Research Program of China (No. 2007CB613608)the National Natural Science Foundation of China (Nos. 50872011 and 50672006)the New Century Excellent Talents Support Program of the Ministry of Education of China (No. 08-0723)
文摘Well-aligned hexagonal ZnO nanotubes （NTs） arrays were synthesized on pretreated indium tin oxide （ITO） substrates by a simple hydro- thermal method. The morphology and structure of the products were characterized by scanning electron microscopy （SEM） and X-ray diffraction analysis （XRD）. A new method of substrate pretreatment was introduced to prepare ZnO coated films. The size of ZnO seeds and the formation rate of ZnO NTs were investigated. Further, the mechanism of the preparation of ZnO NTs was discussed. The photoluminescence （PL） spectrum measurement shows fairly internal defects existing in ZnO nanotubes.
基金Projects(10804101,60908023)supported by the National Natural Science Foundation of ChinaProject(2007CB815102)supported by the National Basic Research Program of ChinaProject(2007B08007)supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.
基金Project supported by the National Natural Science Foundation of China(No.11472163)the National Key Basic Research Project of China(No.2014CB04623)the Shanghai Municipal Commission of Eduction(No.13ZZ067)
文摘The paper investigates continuously changing wrinkle patterns of thin films bonded to a gradient substrate. Three types of gradient substrates including exponential, power-law, and symmetry models are considered. The Galerkin method is used to dis- cretize the governing equation of film bonded to gradient substrates. The wavelength and the normalized amplitude of the wrinkles for substrates of various material gradients are obtained. The numerical simulation based on the finite element method （FEM） is used to evolve the wrinkle patterns. The result agrees well with that of the analytical model. It is concluded that localization of wrinkle patterns strongly depends on the material gradient. The critical membrane force depends on both the minimum value of wrinkle stiffness and the gradient of wrinkle stiffness when the wrinkle stiffness is at its minimum. This work provides a better understanding for local wrinkle formation caused by gradient substrates.
文摘Large-scale growth of copper oxide nanowires was realized on surfaces of various copper-containing substrates, including copper grids, high-purity copper foils, and small copper blocks, by the stress-induced method. A relatively low heating temperature of 340 ~C was demonstrated to give rise to dense nanowire growth with fine crystal structures and high aspect ratio of approximately 300. Gradual cooling process, which is positive for the growth of nanowires on multi-layer substrates, is shown to have no effect on the nanowire growth on other pure copper substrates. Diameter of as-obtained nanowires is mainly dependent on the heating temperature. Moreover, the nanowires growing on copper grids are much longer than those growing on two other substrates.
文摘A two-dimensional kinetic Monte-Carlo(KMC) method was used to approach the thickness distribution of large scale metallic sheet deposited by electron beam physical vapor deposition(EB-PVD) on rotating substrate. The KMC model involves incident atom attachment, adatom diffusion and adatom detachment. The effective deposition rate and effective incident angle along substrate radial were studied as influencing factors of sheet thickness distribution. The KMC simulation results indicate that incident angle is a very important factor to affect the sheet thickness distribution as well as theory deposition mass. The experiments results show that the KMC model can predict the thickness distribution of large scale sheet deposited by EB-PVD on rotating substrate.
基金Supported by the Scientific Research Project of Public Welfare Industry(Agriculture)(201303014-01)Science and Technology Innovation Team of Anhui Academy of Agricultural Sciences(14C0314)the Dean’s Youth Innovation Fund from Anhui Academy of Agricultural Sciences(15B0331)
文摘[Objective] The aim was to find an efficient method to measure available nitrogen, phosphorus and potassium content in vegetable seedling substrate. [ Method] The suitable dosage of leaching agent, ratio of the substrate to water and leaching time for the detection of nutrient contents in the substrate by a soil nutrient measuring instrument were discussed firstly, and then the results of nutrient contents measured by the soil nutrient measuring instrument were compared with that by conventional approaches. [ Result] In compadson with the conventional methods, the av- erage content of available nitrogen measured by the soil nutrient measuring instrument was slightly higher, while the average content of available phosphorus measured by the instrument was lower; the average content of available potassium measured by the instrument was close to that by the conventional method. [ Conclusion] This study could provide us a new method to detect available nitrogen, phosphorus and potassium content in seedling substrate efficiently.
基金Supported by Natural Science Foundation of Hebei Province under Grant No.A2010000004the National Natural Science Foundation of China under Grant Nos.10704022 and 60736042the Key Subject Construction Project of Hebei Province University
文摘The director in nematic liquid crystal cell with a weak anchoring grating substrate and a strong anchoring planar substrate is relative to the coordinates x and z.The influence of the surface geometry of the grating substrate in the cell on the director profile is numerically simulated using the two-dimensional finite-difference iterative method under the condition of one elastic constant approximation and zero driven voltage.The deepness of groove and the cell gap affect the distribution of director.For the relatively shallow groove and the relatively thick cell gap,the director is only dependent on the coordinate z.For the relatively deep groove and the relatively thin cell gap,the director must be dependent on the two coordinates x and z because of the increased elastic strain energy induced by the grating surface.
文摘In this work, the enzymatic hydrolysis reaction of sucrose through invertase under unsteady-state conditions has been investigated. The aim is to evaluate the inhibition phenomena influence on the reaction rate and, then, on the concentration and temperature profiles by simulating the process in a tubular reactor, varying the enzyme concentration and the reactant mixture velocity. The transport phenomena considered during the enzymatic hydrolysis process have been described by means of unsteady-state momentum, mass and energy balance equations, taking into account molecular and convective transport and generation terms. Interpretation and discussion of the results obtained by FEM resolution of PDEs involved allow to understand the relevance of the operating parameters.
文摘Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.
文摘In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(FDTD)method.The proposed structure has the hexagonal close packed of 16×20 circular rods that are suspended in the air substrate with a lattice constant of 606 nm.The plane wave expansion(PWE)method is used to obtain the band diagram for AODFF at an operating wavelength of 1550 nm.The proposed optical flip-flop achieves a low delay time of 0.2 ps and a high contrast ratio(CR)of 10.33 dB.The main advantage of this design is that the input power as low as 1 mW/μm^(2) is sufficient for its operation,since no nonlinear rods are included.In addition,the footprint of the proposed AODFF is 100μm^(2),which is smaller compared to the structures reported in the literature,and it has a fast switching frequency of 5 Tbit/s.
