Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devi...Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devices,showcasing tremendous potential.Therefore,corresponding synthesis techniques for 2D magnetic materials that offer high quality,high yield,low cost,time-saving,and simplicity are highly desired.This review provides a comprehensive overview of recent research advances in preparation of magnetic 2D materials,with a particular focus on the preparation methods employed.Moreover,the characteristics and applications of these magnetic materials are also discussed.Finally,the challenges and prospects of synthesis methods for magnetic 2D materials are briefly addressed.This review serves as a guiding reference for the controlled synthesis of 2D magnetic materials.展开更多
Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based...Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.展开更多
With the recent advancement in nanotechnology,nanoparticles(NPs)offer an ample variety of smart functions than conventional materials in various aspects.As compared to larger particles,NPs possess unique characteristi...With the recent advancement in nanotechnology,nanoparticles(NPs)offer an ample variety of smart functions than conventional materials in various aspects.As compared to larger particles,NPs possess unique characteristics and excellent abilities,such as low toxicity,chemical stability,surface functionality,and biocompatibility.These advantageous properties allow them to be widely utilized in many applications,including biomedical applications,energy applications,IT applications,and industrial applications.In order to fulfill the increasing demands of NP applications,existing NP synthesis methods need to be improved based on the requirements of different applications to further their usage.A comprehensive understanding of the relationships between synthesis parameters and properties of NPs can help us better fine-tune them with designed properties and minimal toxicity.This review paper will discuss the commonly used synthesis methods of functionalized NPs,as well as future directions and challenges to develop various synthesis methods further.展开更多
In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO...In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO particles were monodispersed in NiO/SBA-15 with a NiO loading of less than 15 wt%by using the direct synthesis method.In this case,NiO particles aggregated when NiO loading was over 20 wt%.TPR analysis verified that with direct synthesis method the location boundary of NiO particles on outer and pore surface could be observed clearly,whereas that could not observed in the case of post synthesis method.This indicates that the type of synthesis method displays significant effect on the location of NiO particles dispersed into the SBA-15.Producer gas conversion was carried out using NiO/SBA-15 as catalysts,which were synthesized with different synthesis methods.The gas conversion including methanation occurred at low temperature(i.e.,300-400℃)and the reverse water gas shift(RWGS)reaction at hightemperature(i.e.,400-900℃).High temperatures facilitated CO conversion to CO with CO selectivity close to 100%,regardless of the synthesis method of the used catalyst.At low temperatures the dispersion type of NiO particles affectedthe CO,conversion reaction,i.e.,monodispersed Ni0 particles gave a CO selectivity of close to 100%,similar to thatobtained at high temperature.The aggregated NiO particles resuled in a CO selectivity of less than 100%owing to CH,formation,regardless of synthesis method of catalyst.Therefore,NiO/SBA-15 obtained with direct synthesis methodfavored RWGS reaction because of high CO selectivity.NiOSBA-15 obtained with post synthesis method is suited formethanation because of high CH selectivity,and the conversion of CO,to CHa through methanation increased withincreasing NiO loading.展开更多
The effect of the preparation method on the properties of LaMnO3 and La0.8Sr0.2MnO3 perovskite was studied. Materials were prepared by four methods: sol-gel, chemical combustion, solvothermal and spray pyrolysis and c...The effect of the preparation method on the properties of LaMnO3 and La0.8Sr0.2MnO3 perovskite was studied. Materials were prepared by four methods: sol-gel, chemical combustion, solvothermal and spray pyrolysis and characterized. The effect of the synthesis method on the texture, acid-base character of the surface, reducibility with hydrogen, oxygen desorption, surface composition and catalytic activity for combustion of lean methane was studied. It was found that synthesis method affects physicochemical properties of obtained materials-solvothermally produced materials exhibit well-developed surface area, presence of reactive oxygen species on surface and high catalytic activity for CH4 combustion. Generally, LaMnO3 and La0.8Sr0.2MnO3 perovskites show catalytic activity for lean CH4 combustion comparable or higher than the activity of 0.5 wt.% Pt/Al2O3 but lower than 1 wt.% Pd/Al2O3.展开更多
Coupling is the significant characteristic of parallel mechanism,while it is just the coupling that brings about much difficulty for the configuration design,theoretical analysis and the development of the control sys...Coupling is the significant characteristic of parallel mechanism,while it is just the coupling that brings about much difficulty for the configuration design,theoretical analysis and the development of the control system of the parallel mechanism. And recently,the research on the decoupled parallel mechanism becomes one of the research hot points in the mechanism fields. In this paper,a type synthesis method for the translational decoupled parallel mechanism( TDPM) is proposed based on the screw theory. To achieve the decoupling characteristics of the translational parallel mechanism,the translational decoupled criterion for type synthesis of the branches are presented in this paper. According to this criterion and the realization conditions of rotational degree of freedom of the mechanism proposed former,a large number of branches for the TDPM are obtained. Taking the three degrees of freedom( DOFs) TDPM as an example,the process of type synthesis is discussed in detail. Using this proposed type synthesis method,a serial of translational decoupled parallel mechanisms, including but not limited to all the existing typical 3-DOF TDPMs, are obtained, which identifies the correctness and effective of the method. The contents of this paper provide a reference and possess significant theoretical meanings for the synthesis and development of the novel decoupled parallel mechanisms.展开更多
To consider the infl uence of aftershocks in engineering design, the correlations between main shocks and aftershocks should be examined, and an aftershock simulation method with main shock ground motions needs to be ...To consider the infl uence of aftershocks in engineering design, the correlations between main shocks and aftershocks should be examined, and an aftershock simulation method with main shock ground motions needs to be developed. In this study, the data on the sequences of main shock–aftershock ground motions and other related parameters were collected. Using these data, correlations between the magnitude, frequency, duration and energy of the main shock–aftershock ground motions were investigated. The results showed that the magnitude of the aftershock can be larger than that of the main shock. The shapes of the Fourier amplitude spectra of main shocks and aftershocks were similar;however, the predominant frequency and high-frequency components of the aftershock tended to be larger. Considering the magnitude diff erence between the main shock and the aftershock, the correlation of durations was explored. Additionally, a new concept, the duration ratio, was defi ned to describe the concentration of seismic energy release, and main shock energy was strongly positively correlated with the energy attenuated during the main shock–aftershock sequence. Finally, based on these results regarding correlation, an aftershock synthesis using recorded main shock ground motions was constructed with the trigonometric series method for seismic design, and some examples are given to analyze the rationality of this synthetic method.展开更多
The photocatalyic activity of titania is a very promising mechanism that has many possible applications like purification of air and water [1]-[4]. To make it even more attractive, titania can be combined with silica ...The photocatalyic activity of titania is a very promising mechanism that has many possible applications like purification of air and water [1]-[4]. To make it even more attractive, titania can be combined with silica to increase the photocatalytic efficiency and durability of the photocatalytic material, while lowering the production costs [1]. In this article, relevant literature is reviewed to obtain an overview about the chemistry and physics behind some of the different parameters that lead to cost-effective photocatalytic titania-silica composites. The first part of this review deals with the mechanisms involved in the photocatalytic activity, then the chemistry behind certain methods for the synthesis of the titania-silica composites is discussed, and in the last and third part of this review, the influence of silica supports on titania is discussed. These three sections represent three different fields of research that are combined in this review to obtain better insights on the photocatalytic titania-silica composites. While many research subjects in these fields have been well known for some time now, some subjects are only more recently resolved and some subjects are still under discussion (e.g. the cause for the increased hydrophilic surface of titania after illumination). This article aims to review the most important literature to give an overview of the current situation of the fundamentals of photocatalysis and synthesis of the cost-effective photocatalyic composites. It is found that the most cost-effective photocatalytic titania-silica composites are the ones that have a thin anatase layer coated on silica with a large specific surface area, and are prepared with the precipitation or sol-gel methods.展开更多
This paper presents a synthesis methodology for ECL circuits based on a mixed voltage-current signal representation and operation defined on the voltage and current signals. The ideas presented in this paper are then ...This paper presents a synthesis methodology for ECL circuits based on a mixed voltage-current signal representation and operation defined on the voltage and current signals. The ideas presented in this paper are then demonstrated on the design of an BCL 1-bit full adder. The paper concludes by presenting an algebraic system which is suitable for current signal representation and operation on currents.展开更多
This paper focuses on the observer-based controller design problem and proposes a novel H∞/LTRsysthesis method in which the H∞ design technique is combined with the Loop Transfer Recovery (LTR) design methodology. T...This paper focuses on the observer-based controller design problem and proposes a novel H∞/LTRsysthesis method in which the H∞ design technique is combined with the Loop Transfer Recovery (LTR) design methodology. The method involves two designing steps. First, an H∞ full state feedback controller is designed to satisfy the robust stability and performance specifications, which can be done independently of the recovery optimization. Subsequently, the properties of the H∞ state feedback can be reobtained by designing fullor reduced order observers. A case study is presented to illustrate the proposed method.展开更多
Y2O2S∶Eu nano crystallines were prepared by a new ethanol assisted combustion synthesis method using sulfur-contained organic fuel in an ethanol-aqueous solution. The as-prepared nanocrystallines were characterized b...Y2O2S∶Eu nano crystallines were prepared by a new ethanol assisted combustion synthesis method using sulfur-contained organic fuel in an ethanol-aqueous solution. The as-prepared nanocrystallines were characterized by X-ray diffraction, transmission electron microscope, photoluminescence spectra and X-ray luminescence spectra. It is shown that the assistant fuel ethanol has the effect of decreasing the water needed, simplifying the experiment procedure by dissolving rare earth nitrate and sulfur-contained organic fuel into an even solution, and prompting the formation of rare earth oxysulfide by igniting firstly during heating that leads to combustion decomposition reaction. Y2O2S∶Eu nano crystallines with strong photoluminescence and X-ray luminescence are obtained using thioacetamide as organic fuel. Mixtures of Y2O3∶Eu and Y2O2S∶Eu are acquired using thiourea as fuel, and the content of Y2O2S∶Eu increases until reaches to about half of the Y2O3∶Eu with the increasing amount of thiourea. Y2O2SO4∶Eu emerges when S/Y=6 and increases with increasing thiourea amount.展开更多
Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al_2O_3 comp...Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al_2O_3 composite materials were synthesized by one-step synthesis method. The chemical composition, morphology, structure, and thermal properties were investigated by XRD, EDS, SEM, and DSC. The results show that NaCl can be absorbed by Al_2O_3 particle from 800 to 900 ℃ for Al_2O_3 particle surface is rich active structure. The results also indicate that the leakage of NaCl when the phase change can be prevented by Al_2O_3 particles and the enthalpy of phase change of NaCl-Al_2O_3 material is 362 J/g. The composites have an excellent heat storage capacity. Therefore, this study contributes to one new thought and method to prepare high temperature heat storage material and this material can be applied in future thermal engineering.展开更多
ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66.67% of reactant changed into ZrB2, and the oth...ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66.67% of reactant changed into ZrB2, and the other form Al2O3, which could optimize the properties of carbon-containing materials. Therefore, the method of in-situ synthesizing ZrB2 acting as antioxidant in carbon-containing materials is considered as one of best ways to reduce the cost and ZrB2 as refractories is used on a large-scale.展开更多
Nano molybdenum powder has been applied in many industrial fields in forms of lubricant additives, metallurgical additives, powder sintering additives, and one of raw materials of electrical components, cleaner and sm...Nano molybdenum powder has been applied in many industrial fields in forms of lubricant additives, metallurgical additives, powder sintering additives, and one of raw materials of electrical components, cleaner and smoke suppressor. The processes, mechanisms and prospects of its synthesis methods are comprehensively analysized, including plasma physical vapor deposition technology (PPVD), reduction of MoCl<sub>4</sub> vapor, activated reduction technology, electro-explosion of molybdenum wire (Elex process), pulsed wire discharge technology, electron beam irradiating method, hybrid plasma process, vapor phase reduction of MoO3, and microwave plasma chemical vapor deposition (MPCVD), etc.展开更多
This article reviews the main chemical synthesis methods of sex pheromone of Asian corn borer, common strategies for constructing dou-ble bond, molecular composition and field application progress of sex pheromone of ...This article reviews the main chemical synthesis methods of sex pheromone of Asian corn borer, common strategies for constructing dou-ble bond, molecular composition and field application progress of sex pheromone of Asian corn borer, which will provide reference for biological control of Asian corn borer.展开更多
The subsystem synthesis method has been developed in order to improve computational efficiency for a multibody vehicle dynamics model.Using the subsystem synthesis method,equations of motion of the base body and each ...The subsystem synthesis method has been developed in order to improve computational efficiency for a multibody vehicle dynamics model.Using the subsystem synthesis method,equations of motion of the base body and each subsystem can be solved separately.In the subsystem synthesis method,various coordinate systems can be used and various integration methods can be applied in each subsystem,as long as the effective mass matrix and the effective force vector are properly produced.In this paper,comparative study has been carried out for the subsystem synthesis method with Cartesian coordinates and with joint relative coordinates.Two different integration methods such as an explicit integrator and an explicit implicit integrator are employed.In order to see the accuracy and computational efficiency from the different models based on the different coordinate systems and different integration methods,a rough terrain run simulations has been carried out with a 6×6 off-road multibody vehicle model.展开更多
PEDOT nanotubes were prepared by a template synthesis method. Based on our template, it was deduced that there are two successive processes in the formation of nanotubes. The first step is soakage of the porous templa...PEDOT nanotubes were prepared by a template synthesis method. Based on our template, it was deduced that there are two successive processes in the formation of nanotubes. The first step is soakage of the porous templates by a polymer solution, and the second step is adsorption of free charged cationic groups and doped PEDOT onto the template surface with negative charges. XRD results showed that well orientated PEDOT chains were formed during the synthesis, moreover the arrange conductivity of molecular chains strongly affect the structures of PEDOT nanotubes. The nanotubes were measured to be about 5.5-17.6 S/cm, which is higher than that of nanotube pellet due to the high contact resistance between the adjacent nanotubes.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.22175060 and 21975067)the Natural Science Foundation of Hunan Province of China(Grant Nos.2021JJ10014 and 2021JJ30092).
文摘Two-dimensional(2D)magnetic materials have been demonstrated to have excellent chemical,optical,electrical,and magnetic properties,particularly in the development of multifunctional electronic and spin electronic devices,showcasing tremendous potential.Therefore,corresponding synthesis techniques for 2D magnetic materials that offer high quality,high yield,low cost,time-saving,and simplicity are highly desired.This review provides a comprehensive overview of recent research advances in preparation of magnetic 2D materials,with a particular focus on the preparation methods employed.Moreover,the characteristics and applications of these magnetic materials are also discussed.Finally,the challenges and prospects of synthesis methods for magnetic 2D materials are briefly addressed.This review serves as a guiding reference for the controlled synthesis of 2D magnetic materials.
基金financially supported by the National Key Research&Development Program of China(Nos.2020YFB2008300,2020YFB2008303)。
文摘Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.
文摘With the recent advancement in nanotechnology,nanoparticles(NPs)offer an ample variety of smart functions than conventional materials in various aspects.As compared to larger particles,NPs possess unique characteristics and excellent abilities,such as low toxicity,chemical stability,surface functionality,and biocompatibility.These advantageous properties allow them to be widely utilized in many applications,including biomedical applications,energy applications,IT applications,and industrial applications.In order to fulfill the increasing demands of NP applications,existing NP synthesis methods need to be improved based on the requirements of different applications to further their usage.A comprehensive understanding of the relationships between synthesis parameters and properties of NPs can help us better fine-tune them with designed properties and minimal toxicity.This review paper will discuss the commonly used synthesis methods of functionalized NPs,as well as future directions and challenges to develop various synthesis methods further.
文摘In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO particles were monodispersed in NiO/SBA-15 with a NiO loading of less than 15 wt%by using the direct synthesis method.In this case,NiO particles aggregated when NiO loading was over 20 wt%.TPR analysis verified that with direct synthesis method the location boundary of NiO particles on outer and pore surface could be observed clearly,whereas that could not observed in the case of post synthesis method.This indicates that the type of synthesis method displays significant effect on the location of NiO particles dispersed into the SBA-15.Producer gas conversion was carried out using NiO/SBA-15 as catalysts,which were synthesized with different synthesis methods.The gas conversion including methanation occurred at low temperature(i.e.,300-400℃)and the reverse water gas shift(RWGS)reaction at hightemperature(i.e.,400-900℃).High temperatures facilitated CO conversion to CO with CO selectivity close to 100%,regardless of the synthesis method of the used catalyst.At low temperatures the dispersion type of NiO particles affectedthe CO,conversion reaction,i.e.,monodispersed Ni0 particles gave a CO selectivity of close to 100%,similar to thatobtained at high temperature.The aggregated NiO particles resuled in a CO selectivity of less than 100%owing to CH,formation,regardless of synthesis method of catalyst.Therefore,NiO/SBA-15 obtained with direct synthesis methodfavored RWGS reaction because of high CO selectivity.NiOSBA-15 obtained with post synthesis method is suited formethanation because of high CH selectivity,and the conversion of CO,to CHa through methanation increased withincreasing NiO loading.
基金financed by a statutory activity subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wroclaw University of Technology.
文摘The effect of the preparation method on the properties of LaMnO3 and La0.8Sr0.2MnO3 perovskite was studied. Materials were prepared by four methods: sol-gel, chemical combustion, solvothermal and spray pyrolysis and characterized. The effect of the synthesis method on the texture, acid-base character of the surface, reducibility with hydrogen, oxygen desorption, surface composition and catalytic activity for combustion of lean methane was studied. It was found that synthesis method affects physicochemical properties of obtained materials-solvothermally produced materials exhibit well-developed surface area, presence of reactive oxygen species on surface and high catalytic activity for CH4 combustion. Generally, LaMnO3 and La0.8Sr0.2MnO3 perovskites show catalytic activity for lean CH4 combustion comparable or higher than the activity of 0.5 wt.% Pt/Al2O3 but lower than 1 wt.% Pd/Al2O3.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51005195,51205339)
文摘Coupling is the significant characteristic of parallel mechanism,while it is just the coupling that brings about much difficulty for the configuration design,theoretical analysis and the development of the control system of the parallel mechanism. And recently,the research on the decoupled parallel mechanism becomes one of the research hot points in the mechanism fields. In this paper,a type synthesis method for the translational decoupled parallel mechanism( TDPM) is proposed based on the screw theory. To achieve the decoupling characteristics of the translational parallel mechanism,the translational decoupled criterion for type synthesis of the branches are presented in this paper. According to this criterion and the realization conditions of rotational degree of freedom of the mechanism proposed former,a large number of branches for the TDPM are obtained. Taking the three degrees of freedom( DOFs) TDPM as an example,the process of type synthesis is discussed in detail. Using this proposed type synthesis method,a serial of translational decoupled parallel mechanisms, including but not limited to all the existing typical 3-DOF TDPMs, are obtained, which identifies the correctness and effective of the method. The contents of this paper provide a reference and possess significant theoretical meanings for the synthesis and development of the novel decoupled parallel mechanisms.
基金National Nature Science Foundation of China under Grant No.51778183the National Science Foundation for Distinguished Young Scholars of China under Grant No.51525802
文摘To consider the infl uence of aftershocks in engineering design, the correlations between main shocks and aftershocks should be examined, and an aftershock simulation method with main shock ground motions needs to be developed. In this study, the data on the sequences of main shock–aftershock ground motions and other related parameters were collected. Using these data, correlations between the magnitude, frequency, duration and energy of the main shock–aftershock ground motions were investigated. The results showed that the magnitude of the aftershock can be larger than that of the main shock. The shapes of the Fourier amplitude spectra of main shocks and aftershocks were similar;however, the predominant frequency and high-frequency components of the aftershock tended to be larger. Considering the magnitude diff erence between the main shock and the aftershock, the correlation of durations was explored. Additionally, a new concept, the duration ratio, was defi ned to describe the concentration of seismic energy release, and main shock energy was strongly positively correlated with the energy attenuated during the main shock–aftershock sequence. Finally, based on these results regarding correlation, an aftershock synthesis using recorded main shock ground motions was constructed with the trigonometric series method for seismic design, and some examples are given to analyze the rationality of this synthetic method.
文摘The photocatalyic activity of titania is a very promising mechanism that has many possible applications like purification of air and water [1]-[4]. To make it even more attractive, titania can be combined with silica to increase the photocatalytic efficiency and durability of the photocatalytic material, while lowering the production costs [1]. In this article, relevant literature is reviewed to obtain an overview about the chemistry and physics behind some of the different parameters that lead to cost-effective photocatalytic titania-silica composites. The first part of this review deals with the mechanisms involved in the photocatalytic activity, then the chemistry behind certain methods for the synthesis of the titania-silica composites is discussed, and in the last and third part of this review, the influence of silica supports on titania is discussed. These three sections represent three different fields of research that are combined in this review to obtain better insights on the photocatalytic titania-silica composites. While many research subjects in these fields have been well known for some time now, some subjects are only more recently resolved and some subjects are still under discussion (e.g. the cause for the increased hydrophilic surface of titania after illumination). This article aims to review the most important literature to give an overview of the current situation of the fundamentals of photocatalysis and synthesis of the cost-effective photocatalyic composites. It is found that the most cost-effective photocatalytic titania-silica composites are the ones that have a thin anatase layer coated on silica with a large specific surface area, and are prepared with the precipitation or sol-gel methods.
基金Supported by NNSF of China(No169573008)DARPA under contract # F33615-95-C-1627
文摘This paper presents a synthesis methodology for ECL circuits based on a mixed voltage-current signal representation and operation defined on the voltage and current signals. The ideas presented in this paper are then demonstrated on the design of an BCL 1-bit full adder. The paper concludes by presenting an algebraic system which is suitable for current signal representation and operation on currents.
文摘This paper focuses on the observer-based controller design problem and proposes a novel H∞/LTRsysthesis method in which the H∞ design technique is combined with the Loop Transfer Recovery (LTR) design methodology. The method involves two designing steps. First, an H∞ full state feedback controller is designed to satisfy the robust stability and performance specifications, which can be done independently of the recovery optimization. Subsequently, the properties of the H∞ state feedback can be reobtained by designing fullor reduced order observers. A case study is presented to illustrate the proposed method.
文摘Y2O2S∶Eu nano crystallines were prepared by a new ethanol assisted combustion synthesis method using sulfur-contained organic fuel in an ethanol-aqueous solution. The as-prepared nanocrystallines were characterized by X-ray diffraction, transmission electron microscope, photoluminescence spectra and X-ray luminescence spectra. It is shown that the assistant fuel ethanol has the effect of decreasing the water needed, simplifying the experiment procedure by dissolving rare earth nitrate and sulfur-contained organic fuel into an even solution, and prompting the formation of rare earth oxysulfide by igniting firstly during heating that leads to combustion decomposition reaction. Y2O2S∶Eu nano crystallines with strong photoluminescence and X-ray luminescence are obtained using thioacetamide as organic fuel. Mixtures of Y2O3∶Eu and Y2O2S∶Eu are acquired using thiourea as fuel, and the content of Y2O2S∶Eu increases until reaches to about half of the Y2O3∶Eu with the increasing amount of thiourea. Y2O2SO4∶Eu emerges when S/Y=6 and increases with increasing thiourea amount.
基金Funded by the National Natural Science of China(No.2012BAA05B06)
文摘Thermal energy storage is an attractive option for effectiveness since it gives flexibility and reduces energy consumption and costs. New composite materials for storage and transformation of heat of NaCl-Al_2O_3 composite materials were synthesized by one-step synthesis method. The chemical composition, morphology, structure, and thermal properties were investigated by XRD, EDS, SEM, and DSC. The results show that NaCl can be absorbed by Al_2O_3 particle from 800 to 900 ℃ for Al_2O_3 particle surface is rich active structure. The results also indicate that the leakage of NaCl when the phase change can be prevented by Al_2O_3 particles and the enthalpy of phase change of NaCl-Al_2O_3 material is 362 J/g. The composites have an excellent heat storage capacity. Therefore, this study contributes to one new thought and method to prepare high temperature heat storage material and this material can be applied in future thermal engineering.
基金ItemSponsored by National"863"Plan (2002AA335060) National Natural Science Foundation of China (50332010)
文摘ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66.67% of reactant changed into ZrB2, and the other form Al2O3, which could optimize the properties of carbon-containing materials. Therefore, the method of in-situ synthesizing ZrB2 acting as antioxidant in carbon-containing materials is considered as one of best ways to reduce the cost and ZrB2 as refractories is used on a large-scale.
文摘Nano molybdenum powder has been applied in many industrial fields in forms of lubricant additives, metallurgical additives, powder sintering additives, and one of raw materials of electrical components, cleaner and smoke suppressor. The processes, mechanisms and prospects of its synthesis methods are comprehensively analysized, including plasma physical vapor deposition technology (PPVD), reduction of MoCl<sub>4</sub> vapor, activated reduction technology, electro-explosion of molybdenum wire (Elex process), pulsed wire discharge technology, electron beam irradiating method, hybrid plasma process, vapor phase reduction of MoO3, and microwave plasma chemical vapor deposition (MPCVD), etc.
基金Supported by Shandong Provincial Key Research and Development Program(2019GSF109062)Agricultural Scientific and Technological Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2016B12)Major Agricultural Application Technology Innovation Projects of Shan-dong Province。
文摘This article reviews the main chemical synthesis methods of sex pheromone of Asian corn borer, common strategies for constructing dou-ble bond, molecular composition and field application progress of sex pheromone of Asian corn borer, which will provide reference for biological control of Asian corn borer.
基金Supported by the National Natural Science Foundation of China （No. 60403044, No. 60373070） and partly funded by Microsoft Research Asia： Project 2004-Image-01.
基金supported from by Unmanned Technology Research Center (UTRC) at Korea Advanced Institute of Science and Technology (KAIST),originally funded by DAPA,ADD
文摘The subsystem synthesis method has been developed in order to improve computational efficiency for a multibody vehicle dynamics model.Using the subsystem synthesis method,equations of motion of the base body and each subsystem can be solved separately.In the subsystem synthesis method,various coordinate systems can be used and various integration methods can be applied in each subsystem,as long as the effective mass matrix and the effective force vector are properly produced.In this paper,comparative study has been carried out for the subsystem synthesis method with Cartesian coordinates and with joint relative coordinates.Two different integration methods such as an explicit integrator and an explicit implicit integrator are employed.In order to see the accuracy and computational efficiency from the different models based on the different coordinate systems and different integration methods,a rough terrain run simulations has been carried out with a 6×6 off-road multibody vehicle model.
基金Funded National Natural Science Foundation of China(No.: 60372002)
文摘PEDOT nanotubes were prepared by a template synthesis method. Based on our template, it was deduced that there are two successive processes in the formation of nanotubes. The first step is soakage of the porous templates by a polymer solution, and the second step is adsorption of free charged cationic groups and doped PEDOT onto the template surface with negative charges. XRD results showed that well orientated PEDOT chains were formed during the synthesis, moreover the arrange conductivity of molecular chains strongly affect the structures of PEDOT nanotubes. The nanotubes were measured to be about 5.5-17.6 S/cm, which is higher than that of nanotube pellet due to the high contact resistance between the adjacent nanotubes.
