An explicit topology optimization method for the stiffener layout of composite stiffened panels is proposed based on moving morphable components(MMCs).The skin and stiffeners are considered as panels with different be...An explicit topology optimization method for the stiffener layout of composite stiffened panels is proposed based on moving morphable components(MMCs).The skin and stiffeners are considered as panels with different bending stiffnesses,with the use of equivalent stiffness method.Then the location and geometric properties of composite stiffeners are determined by several MMCs to perform topology optimization,which can greatly simplify the finite element model.With the objective of maximizing structural stiffness,several typical cases with various loading and boundary conditions are selected as numerical examples to demonstrate the proposed method.The numerical examples illustrate that the proposed method can provide clear stiffener layout and explicit geometry information,which is not limited within the framework of parameter and size optimization.The mechanical properties of composite stiffened panels can be fully enhanced.展开更多
Background:The simplest and most convenient food technology is the using of dry composite mixtures.They have a lot of advantages.Dry composite mixtures,which would completely be the basis for the production of persona...Background:The simplest and most convenient food technology is the using of dry composite mixtures.They have a lot of advantages.Dry composite mixtures,which would completely be the basis for the production of personalized food concentrates,are not represented.The development of such dry composite mixtures is actual and of scientific and practical interest.The purpose of this research is the selection and justification of local import-substituting raw materials components for dry composite mixtures used as the basis for the production of food concentrates.As the objects of research,the raw materials components of the starch,fruit and vegetable,industry were selected.The work uses currently accepted standard research methods for organoleptic and physic-chemical parameters of raw materials components.The research was carried out within of the project“Theoretical Substantiation of Production Technology and the Development of Import-Substituting Food Products of Functional Purpose Based on Dry Composite Mixtures”,funded by the Belarusian Republican Foundation for Basic Research.Based on the researches,it was found out that in the composition of dry composite mixtures for the production of food concentrates it is expedient to use the following raw materials:potato starch,extruded corn starch,dried carrots,dried beets,dried topinambur and dried apples in chopped form.展开更多
A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation.It was ...A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation.It was demonstrated that Co3O_(4)phase was the main component in regulation.The combined results of X-ray photoelectron spectroscopy (XPS),temperature-programmed desorption of oxygen (O_(2)-TPD),temperature-programmed reduction of hydrogen (H_(2)-TPR),temperature-programmed desorption of ammonia/carbon dioxide (NH_(3)/CO_(2)-TPD) revealed that component regulation led to more oxygen vacancies and exposure of surface Co_(2)+,lower surface basicity and optimized acidity,which were beneficial for adsorption of active oxygen species and activation of methane molecules,resulting in the excellent catalytic oxidation performance.Especially,the (3.5)LC-C (3.5 is Co-to-La molar ratio) showed the optimum activity and the T50and T90(the temperature at which the CH_(4)conversion rate was 50%and 90%,respectively) were 318 and 367℃,respectively.Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spectroscopy characterization,it was also found that the catalytic mechanism changes from the “Rideal-Eley” mechanism to the “Two-term” mechanism depending on the temperature windows in which the reaction takes place.Besides,the use of the “Flynn-Wall-Ozawa” model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy,further expanding the application scope of carboncontaining composites.展开更多
To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIP...To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIPS-100 ion thruster developed by the Lanzhou Institute of Physics.This study focused on small-diameter configurations of carbon-carbon composite material grids.Successful development was achieved for both a 10 cm split carbon-carbon planar grid and an integrated carbon-carbon convex grid component.Performance variations among different configurations were investigated through extensive performance tests across the wide-range from 1 to 25 mN,as well as 200 h lifespan assessments under typical conditions at 20 mN.The results indicate that the two configurations of the carbon-carbon grid can achieve stable operation across the broad range of 1-20 mN,with beam current fluctuations ranging from 368 to 379 mA and accel grid current fluctuations between 1.58 and 1.81 mA.Furthermore,the key performance parameters of these grids were comparable to those of the traditional molybdenum grids.Under conditions of high thrust and power,the carbon-carbon grid demonstrated a significant reduction in the intercepted current at the accel grid.In comparison to the split carbon-carbon planar grid,the weight of the integrated carbon-carbon convex composite grid was reduced by 17.5%,the anode voltage decreased by approximately 2.4%-8.6%,and the cathode keeper voltage was reduced by approximately 3.5%-12.4%.It can be concluded that the integrated carbon-carbon convex grid offers distinct advantages in terms of hot-state structural stability,suppression of grid etching rates,and enhancement of thruster discharge efficiency.展开更多
A new approach for fabricating B4C/Cu graded composite by rapid self-resistance sintering under ultra-high pressure was presented, by which a near dense B4C/Cu graded composite with a compositional spectrum of 0-100% ...A new approach for fabricating B4C/Cu graded composite by rapid self-resistance sintering under ultra-high pressure was presented, by which a near dense B4C/Cu graded composite with a compositional spectrum of 0-100% was successfully fabricated. Plasma relevant performances of sintered B4C/Cu composite were preliminarily characterized, it is found that its chemical sputtering yield is 70% lower than that of SMF800 nuclear graphite under 2.7keV D+ irradiation, and almost no damages after 66 shots of in situ plasma discharge in HL-1 Tokamak facility, which indicates B4C/Cu plasma facing component has a good physical and chemical sputtering resistance performance compared with nuclear graphite.展开更多
A system of finished Componeer composite veneers is a unique and having no analogy in the world elaboration of the Swisscompany Coltene/Whaledent, an outcome of almost halfa century experience of the company working i...A system of finished Componeer composite veneers is a unique and having no analogy in the world elaboration of the Swisscompany Coltene/Whaledent, an outcome of almost halfa century experience of the company working in a field of composite materials.It combines the best features of direct and indirect restoration methods. The system is fulfilled of nanocomposite Synergy D6 that hashigh mechanical strength, convenience for workable consistency, color stability and a system of halftone shades, which facilitates colormatching. All this allows achieving excellent aesthetic results in minimal time. Application of an original standard scale givespossibility effectively assess optical properties of dental hard tissues and develop an implementation strategy of restoration before workstarted. Formation of Componeer form, polymerization and polishing at factory allow a practitioner fully utilize effect of＂fluorescence＂ inherent to the material. All this allows us to position the Componeer system as a serious alternative to non-directmethods of restoration with the possibility of both high aesthetic and cosmetic reconstruction reliability.展开更多
Inductively coupled plasma optical emission spectrometric approach（1CP-OES） is used to determine the potassium content as principal component in pyrotechnic compositions used for fireworks and firecrackers. Element ...Inductively coupled plasma optical emission spectrometric approach（1CP-OES） is used to determine the potassium content as principal component in pyrotechnic compositions used for fireworks and firecrackers. Element of potassium is conunonly found in potassium nitrate and potassium perchlorate in pyrotechnic compositions in fireworks and firecrackers. Statistical analysis shows that potassium nitrate content in pyrotechnics is between 10% to 60% and the potassium perchlorate content is between 20% to 70%,which counted in the content of potassium element is between 4% to 23%. Concept of this method： considering the weight of the sample is 400rag,constant volume is 1L and the concentration of potassium is between 10 mg/L to 90 mg/L in sample solution, the determination scope of the method for the potassium content would be between 1% to 23%.Further experiments proved that the fitting correlation coefficient of potassium calibration curve is 0.9997 or higher, recovery is 89.15%-100.23%.The allowable differential value is 0.4% between two single tests under repeatable conditions. This method can completely satisfy the requirements of the fireworks and firecrackers industry with high accuracy and good precision.展开更多
Inductively coupled plasma optical emission spectrometric approach（ICP-OES）is used to determine the magnesium and aluminum content as principal components in pyrotechnic compositions used for fireworks and firecrack...Inductively coupled plasma optical emission spectrometric approach（ICP-OES）is used to determine the magnesium and aluminum content as principal components in pyrotechnic compositions used for fireworks and firecrackers. Elements of magnesium and aluminum are commonly found in aluminum powder or magnesium-aluminum alloy powder in pyrotechnic compositions in fireworks and firecrackers. Statistical analysis shows that the magnesium content in pyrotechnics is between 8% to 30% and the aluminum content is between 8% to 35%（roughly）.Concept of this method： suppose the weight of the sample is 400rag,constant volume is IL and the concentlation of magnesium and aluminum is between 12mg/L to 160mg/L in sample solution, the determination scope of the method for magnesium and aluminum content would be between 3% to 40%.Further experiments proved that the fitting correlation coefficient of the magnesium calibration curve is 0.9999 or higher, recovery is 101.01% -101.96%.The fitting correlation coefficient of the aluminum calibration curve is 0.9999 or higher, recovery is 99.36%-103.07%. The allowable differential value is 0.4% between two single tests under repeatable conditions. This method can completely satisfy the requirements of the fireworks and firecrackers industry with high accuracy and good precision.展开更多
Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web...Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web services and choreography, and their operations and properties are presented in a consistent and uniform manner. Service components are published externally as normal web services and can thus be employed by webbased applications. In order to improve reusability and testability of service components, the concept of composition pattern is also proposed, which presents the relationships among service components. The relationships and relationship compositions have a rigorous semantic, so that composite components can be validated at the configuration stage. The composition patterns support to integrate service components of various levels of granularity. Experience indicates that the application assembly can effectively be conducted by understanding, selecting, and reusing components easily.展开更多
An engine rubber mounting is one of the important parts of a vehicle. It is a function to isolate or absorb and to reduce vibration to the vehicle body thus to the passenger itself. Due to the engine compartments envi...An engine rubber mounting is one of the important parts of a vehicle. It is a function to isolate or absorb and to reduce vibration to the vehicle body thus to the passenger itself. Due to the engine compartments environment such as heat and massive vibration due to road conditions, the engine rubber mountings lifespan has been reduced. Thus several studies have been conducted to upgrade the material lifespan to make it more reliable and better engine mounting components. This paper presents the conceptual design of kenaf fiber polymer as automotive engine rubber mounting composites using the integration of Theory of Inventive Problem Solving(TRIZ). In this early stage, the solution is generated using 40 inventive principles and TRIZ contradiction method. The solution parameter for the specific design character is the selected using the morphological chart to develop a systematic conceptual design for the component. Four(4) innovative design concepts were produced and Analytic Network Process(ANP)methods were utilized to perform the multi-criteria decision-making process of selecting the best concept design for the polymer composite engine rubber mounting component.展开更多
To determine the chemical composition of Galla chinensisextract （GCE） by several analysis techniques and to compare the efficacy of GCE and its main component（s） in inhibition of enamel demineralization, for the d...To determine the chemical composition of Galla chinensisextract （GCE） by several analysis techniques and to compare the efficacy of GCE and its main component（s） in inhibition of enamel demineralization, for the development of future anticaries agents, main organic composition of GCE was qualitatively determined by liquid chromatography-time of flight-mass spectrometry （LC-TOF-MS） and quantified by high-performance liquid chromatography-diode array detector （HPLC-DAD）. Inorganic ions were tested by inductively coupled plasma-atomic emission spectroscopy and F was especially measured by ion chromatography. Then, bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times. Each cycle included 5-min applications with one of four treatments： 4g.L-1 GCE solution, 4g.L-1 gallic acid （GA） solution, I g.L-1 NaF solution （positive control）, deionized water （DDW, negative control）, and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer. Acidic buffers were retained for calcium analysis. The main organic composition of GCE were GA and its isomer, and, to a lesser extent, small molecule gallotannins. The content of GA in GCE was 71.3%±0.2% （w/w）. Inorganic ions were present in various amounts, of which Ca was （136±2.82） μg.g-1, and Zn was （6.8±0.1） μg.g-1. No F was detected in GCE. in pH cycling, GA showed an effect similar to GCE in inhibiting enamel demineralization （P〉0.05）. GA was found to be the main effective, demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.展开更多
At present,developing high-efficiency microwave absorption materials with properties including lightweight,thin thickness,strong absorbing intensity and broad bandwidth is an urgent demand to solve the electromagnetic...At present,developing high-efficiency microwave absorption materials with properties including lightweight,thin thickness,strong absorbing intensity and broad bandwidth is an urgent demand to solve the electromagnetic pollution issues.An ideal microwave absorber should have excellent dielectric and magnetic loss capabilities,thereby inducing attenuation and absorption of incident electromagnetic radiation.Recently,various carbon/magnetic metal composites have been developed and expected to become promising candidates for high-performance microwave absorbers.In this review,we introduce the mechanisms of microwave absorption and summarize the recent advances in carbon/magnetic metal composites.Preparation methods and microwave absorption properties of carbon/magnetic metal composites with different components,morphologies and microstructures are discussed in detail.Finally,the challenges and future prospects of carbon/magnetic metal absorbing materials are also proposed,which will be useful to develop high-performance microwave absorption materials.展开更多
After describing the characteristics of programming paradigm, this paper introduces the approach of code component composition reuse in detail, proposes and discusses viewpoint that code component composition reuse is...After describing the characteristics of programming paradigm, this paper introduces the approach of code component composition reuse in detail, proposes and discusses viewpoint that code component composition reuse is a kind of new programming paradigm. This paper also specifies the characteristics of this new programming paradigm in detail, and points out some issues that must be resolved for using this new programming paradigm.展开更多
Fiber-reinforced composite materials have excellent specific stiffness,specific strength,and other properties,and have been increasingly widely used in the field of advanced structures.However,the design space dimensi...Fiber-reinforced composite materials have excellent specific stiffness,specific strength,and other properties,and have been increasingly widely used in the field of advanced structures.However,the design space dimensions of fiber-reinforced composite materials will expand explosively,bringing challenges to the efficient analysis and optimal design of structures.In this paper,the authors propose an explicit topology optimization method based on the moving morphable components for designing the fiber-reinforced material.We constrain the intersection area between components to guarantee the independence of each component and avoid the situation that one component is cut by other components.Adding the fiber orientation angle as a design variable,the method can optimize the structural layout and the fiber orientation angle concurrently under the given number of fiber layers and layer thickness.We use two classical examples to verify the feasibility and accuracy of the proposed method.The optimized results are in good agreement with the designs obtained by the 99-line code.The authors also popularize the proposed method to engineering structure.The results manifest that the proposed method has great value in engineering application.展开更多
Hydrogen absorption composite powder of Mg incorporated with Ni and CrCl3 （88∶10∶2 in mass ratio） was prepared by reactive milling in hydrogen atmosphere. Hydriding/dehydriding performances were measured by self-m...Hydrogen absorption composite powder of Mg incorporated with Ni and CrCl3 （88∶10∶2 in mass ratio） was prepared by reactive milling in hydrogen atmosphere. Hydriding/dehydriding performances were measured by self-made apparatus. The results show that reactive milling and multi-component addition of Ni and CrCl3 reduce the stability of hydride and improve the sorption performance of Mg-based materials. With powder milled for 60h, hydriding basically completes within 300s （250℃, 2.0MPa） and phase transformation fraction reaches 0.78. The phase transformation rate of hydriding/dehydriding progress increases significantly with the reduced particles size of powder while good kinetics of dehydriding at a relatively low temperature is gained with small grain size of hydride. Rapid temperature variations in a short span of time resulted from remarkable calorific effects of rapid phase transformation are detected in hydriding/dehydriding progress. The results of thermogravimetric and differential scanning calorimetric（TG/DSC） indicate that the onset temperature of desorption of composite milled for 100h is 272℃.展开更多
The saturate,aromatics,resin and asphaltene components of paraffin-base(PB)and naphthenic-base(HB)crude oil are separated by chromatographic column.The acidic components of crude oil are extracted by compounded polar ...The saturate,aromatics,resin and asphaltene components of paraffin-base(PB)and naphthenic-base(HB)crude oil are separated by chromatographic column.The acidic components of crude oil are extracted by compounded polar solvents and identified by methyl esterification of diazomethane.The acidic components before and after asphaltene removal are investigated by gas chromatography-mass spectrometer.The effect of four fractions in simulated oil on interfacial activity is discussed.The results show PB is rich in naphthalene series and tri-aromatic steroids,and HB has a high content of phenanthrene series,chrysene series and methylpyrene,besides higher content of naphthalene series.The long carbon chain acids in HB oil decrease significantly by asphaltenes removal,confirming the presence of heavy oil acids in asphaltene.A little amount of saturates and aromatics in simulated oil can reduce the interfacial tension(IFT).When the content of asphaltenes of simulated oil is increased,IFT is initially decreased and finally increased because of stability of asphaltenes.When resin is increased,IFT is initially increased and then decreased.Simulated oil containing the resin from naphthenic-base oil is more sensitive to alkali than that of paraffin-base resin,which can reduce the IFT between oil and water at a larger range.展开更多
基金The financial supports from the National Key Research and Development Plan(2016YFB0201601)the Foundation for Innovative Research Groups of the National Natural Science Foundation(11821202)+3 种基金the National Natural Science Foundation(11872138,11702048,11732004 and 11772076)Program for Changjiang Scholars,Innovative Research Team in University(PCSIRT)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)Liaoning Natural Science Foundation Guidance Plan(20170520293)111 Project(B14013)are gratefully acknowledged.
文摘An explicit topology optimization method for the stiffener layout of composite stiffened panels is proposed based on moving morphable components(MMCs).The skin and stiffeners are considered as panels with different bending stiffnesses,with the use of equivalent stiffness method.Then the location and geometric properties of composite stiffeners are determined by several MMCs to perform topology optimization,which can greatly simplify the finite element model.With the objective of maximizing structural stiffness,several typical cases with various loading and boundary conditions are selected as numerical examples to demonstrate the proposed method.The numerical examples illustrate that the proposed method can provide clear stiffener layout and explicit geometry information,which is not limited within the framework of parameter and size optimization.The mechanical properties of composite stiffened panels can be fully enhanced.
文摘Background:The simplest and most convenient food technology is the using of dry composite mixtures.They have a lot of advantages.Dry composite mixtures,which would completely be the basis for the production of personalized food concentrates,are not represented.The development of such dry composite mixtures is actual and of scientific and practical interest.The purpose of this research is the selection and justification of local import-substituting raw materials components for dry composite mixtures used as the basis for the production of food concentrates.As the objects of research,the raw materials components of the starch,fruit and vegetable,industry were selected.The work uses currently accepted standard research methods for organoleptic and physic-chemical parameters of raw materials components.The research was carried out within of the project“Theoretical Substantiation of Production Technology and the Development of Import-Substituting Food Products of Functional Purpose Based on Dry Composite Mixtures”,funded by the Belarusian Republican Foundation for Basic Research.Based on the researches,it was found out that in the composition of dry composite mixtures for the production of food concentrates it is expedient to use the following raw materials:potato starch,extruded corn starch,dried carrots,dried beets,dried topinambur and dried apples in chopped form.
基金supported by the National Natural Science Foundation of China (No.U20A201714)Hebei Education Department (No.QN2021059)Natural Science Foundation of Hebei Province (Nos.B2021208033 and B2021208040)。
文摘A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation.It was demonstrated that Co3O_(4)phase was the main component in regulation.The combined results of X-ray photoelectron spectroscopy (XPS),temperature-programmed desorption of oxygen (O_(2)-TPD),temperature-programmed reduction of hydrogen (H_(2)-TPR),temperature-programmed desorption of ammonia/carbon dioxide (NH_(3)/CO_(2)-TPD) revealed that component regulation led to more oxygen vacancies and exposure of surface Co_(2)+,lower surface basicity and optimized acidity,which were beneficial for adsorption of active oxygen species and activation of methane molecules,resulting in the excellent catalytic oxidation performance.Especially,the (3.5)LC-C (3.5 is Co-to-La molar ratio) showed the optimum activity and the T50and T90(the temperature at which the CH_(4)conversion rate was 50%and 90%,respectively) were 318 and 367℃,respectively.Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spectroscopy characterization,it was also found that the catalytic mechanism changes from the “Rideal-Eley” mechanism to the “Two-term” mechanism depending on the temperature windows in which the reaction takes place.Besides,the use of the “Flynn-Wall-Ozawa” model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy,further expanding the application scope of carboncontaining composites.
基金National Key R&D Program of China(No.2022YFB3403500)the Science and Technology Program of Gansu Province(No.22JR5RA784).
文摘To address the future application requirements of carbon-based material grids for ion thrusters characterized by high thrust,elevated specific impulse,and extended operational life,research was conducted using the LIPS-100 ion thruster developed by the Lanzhou Institute of Physics.This study focused on small-diameter configurations of carbon-carbon composite material grids.Successful development was achieved for both a 10 cm split carbon-carbon planar grid and an integrated carbon-carbon convex grid component.Performance variations among different configurations were investigated through extensive performance tests across the wide-range from 1 to 25 mN,as well as 200 h lifespan assessments under typical conditions at 20 mN.The results indicate that the two configurations of the carbon-carbon grid can achieve stable operation across the broad range of 1-20 mN,with beam current fluctuations ranging from 368 to 379 mA and accel grid current fluctuations between 1.58 and 1.81 mA.Furthermore,the key performance parameters of these grids were comparable to those of the traditional molybdenum grids.Under conditions of high thrust and power,the carbon-carbon grid demonstrated a significant reduction in the intercepted current at the accel grid.In comparison to the split carbon-carbon planar grid,the weight of the integrated carbon-carbon convex composite grid was reduced by 17.5%,the anode voltage decreased by approximately 2.4%-8.6%,and the cathode keeper voltage was reduced by approximately 3.5%-12.4%.It can be concluded that the integrated carbon-carbon convex grid offers distinct advantages in terms of hot-state structural stability,suppression of grid etching rates,and enhancement of thruster discharge efficiency.
基金This work was financially supported by "863 " key foundation of China (No. 715-011-0230).
文摘A new approach for fabricating B4C/Cu graded composite by rapid self-resistance sintering under ultra-high pressure was presented, by which a near dense B4C/Cu graded composite with a compositional spectrum of 0-100% was successfully fabricated. Plasma relevant performances of sintered B4C/Cu composite were preliminarily characterized, it is found that its chemical sputtering yield is 70% lower than that of SMF800 nuclear graphite under 2.7keV D+ irradiation, and almost no damages after 66 shots of in situ plasma discharge in HL-1 Tokamak facility, which indicates B4C/Cu plasma facing component has a good physical and chemical sputtering resistance performance compared with nuclear graphite.
文摘A system of finished Componeer composite veneers is a unique and having no analogy in the world elaboration of the Swisscompany Coltene/Whaledent, an outcome of almost halfa century experience of the company working in a field of composite materials.It combines the best features of direct and indirect restoration methods. The system is fulfilled of nanocomposite Synergy D6 that hashigh mechanical strength, convenience for workable consistency, color stability and a system of halftone shades, which facilitates colormatching. All this allows achieving excellent aesthetic results in minimal time. Application of an original standard scale givespossibility effectively assess optical properties of dental hard tissues and develop an implementation strategy of restoration before workstarted. Formation of Componeer form, polymerization and polishing at factory allow a practitioner fully utilize effect of＂fluorescence＂ inherent to the material. All this allows us to position the Componeer system as a serious alternative to non-directmethods of restoration with the possibility of both high aesthetic and cosmetic reconstruction reliability.
文摘Inductively coupled plasma optical emission spectrometric approach（1CP-OES） is used to determine the potassium content as principal component in pyrotechnic compositions used for fireworks and firecrackers. Element of potassium is conunonly found in potassium nitrate and potassium perchlorate in pyrotechnic compositions in fireworks and firecrackers. Statistical analysis shows that potassium nitrate content in pyrotechnics is between 10% to 60% and the potassium perchlorate content is between 20% to 70%,which counted in the content of potassium element is between 4% to 23%. Concept of this method： considering the weight of the sample is 400rag,constant volume is 1L and the concentration of potassium is between 10 mg/L to 90 mg/L in sample solution, the determination scope of the method for the potassium content would be between 1% to 23%.Further experiments proved that the fitting correlation coefficient of potassium calibration curve is 0.9997 or higher, recovery is 89.15%-100.23%.The allowable differential value is 0.4% between two single tests under repeatable conditions. This method can completely satisfy the requirements of the fireworks and firecrackers industry with high accuracy and good precision.
文摘Inductively coupled plasma optical emission spectrometric approach（ICP-OES）is used to determine the magnesium and aluminum content as principal components in pyrotechnic compositions used for fireworks and firecrackers. Elements of magnesium and aluminum are commonly found in aluminum powder or magnesium-aluminum alloy powder in pyrotechnic compositions in fireworks and firecrackers. Statistical analysis shows that the magnesium content in pyrotechnics is between 8% to 30% and the aluminum content is between 8% to 35%（roughly）.Concept of this method： suppose the weight of the sample is 400rag,constant volume is IL and the concentlation of magnesium and aluminum is between 12mg/L to 160mg/L in sample solution, the determination scope of the method for magnesium and aluminum content would be between 3% to 40%.Further experiments proved that the fitting correlation coefficient of the magnesium calibration curve is 0.9999 or higher, recovery is 101.01% -101.96%.The fitting correlation coefficient of the aluminum calibration curve is 0.9999 or higher, recovery is 99.36%-103.07%. The allowable differential value is 0.4% between two single tests under repeatable conditions. This method can completely satisfy the requirements of the fireworks and firecrackers industry with high accuracy and good precision.
基金The National Basic Research Program of China (973Program) (No.1999032710).
文摘Due to the fact that the existing web service description methods cannot address the issue of service reuse of various levels of granularity, the concept of service component is introduced, which packages together web services and choreography, and their operations and properties are presented in a consistent and uniform manner. Service components are published externally as normal web services and can thus be employed by webbased applications. In order to improve reusability and testability of service components, the concept of composition pattern is also proposed, which presents the relationships among service components. The relationships and relationship compositions have a rigorous semantic, so that composite components can be validated at the configuration stage. The composition patterns support to integrate service components of various levels of granularity. Experience indicates that the application assembly can effectively be conducted by understanding, selecting, and reusing components easily.
基金Universiti Kuala Lumpurthe Ministry of Higher Education,Malaysia for providing the scholarship award and financially support through UniKL Grant Scheme(STRG 15144)to the principal author in this projectHiCOE grant(6369107)from Ministry of Higher Education,Malaysia
文摘An engine rubber mounting is one of the important parts of a vehicle. It is a function to isolate or absorb and to reduce vibration to the vehicle body thus to the passenger itself. Due to the engine compartments environment such as heat and massive vibration due to road conditions, the engine rubber mountings lifespan has been reduced. Thus several studies have been conducted to upgrade the material lifespan to make it more reliable and better engine mounting components. This paper presents the conceptual design of kenaf fiber polymer as automotive engine rubber mounting composites using the integration of Theory of Inventive Problem Solving(TRIZ). In this early stage, the solution is generated using 40 inventive principles and TRIZ contradiction method. The solution parameter for the specific design character is the selected using the morphological chart to develop a systematic conceptual design for the component. Four(4) innovative design concepts were produced and Analytic Network Process(ANP)methods were utilized to perform the multi-criteria decision-making process of selecting the best concept design for the polymer composite engine rubber mounting component.
基金supported by the National Natural Science Foundation of China (grant nos. 30572409 and 30430800)Youth Foundation of Sichuan Province in China (grant no. 07ZQ026-020)
文摘To determine the chemical composition of Galla chinensisextract （GCE） by several analysis techniques and to compare the efficacy of GCE and its main component（s） in inhibition of enamel demineralization, for the development of future anticaries agents, main organic composition of GCE was qualitatively determined by liquid chromatography-time of flight-mass spectrometry （LC-TOF-MS） and quantified by high-performance liquid chromatography-diode array detector （HPLC-DAD）. Inorganic ions were tested by inductively coupled plasma-atomic emission spectroscopy and F was especially measured by ion chromatography. Then, bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times. Each cycle included 5-min applications with one of four treatments： 4g.L-1 GCE solution, 4g.L-1 gallic acid （GA） solution, I g.L-1 NaF solution （positive control）, deionized water （DDW, negative control）, and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer. Acidic buffers were retained for calcium analysis. The main organic composition of GCE were GA and its isomer, and, to a lesser extent, small molecule gallotannins. The content of GA in GCE was 71.3%±0.2% （w/w）. Inorganic ions were present in various amounts, of which Ca was （136±2.82） μg.g-1, and Zn was （6.8±0.1） μg.g-1. No F was detected in GCE. in pH cycling, GA showed an effect similar to GCE in inhibiting enamel demineralization （P〉0.05）. GA was found to be the main effective, demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.
基金financially supported by the National Science and Technology Major Project(No.2017-VI-0008-0078)the Joint Fund of the National Natural Science Foundation of China and Baosteel Group Corporation(No.U1560106)+1 种基金the Aeronautical Science Foundation of China(No.2016ZF51050)the Scientific Research Foundation for the Returned Overseas Chinese Scholars(State Education Ministry)。
文摘At present,developing high-efficiency microwave absorption materials with properties including lightweight,thin thickness,strong absorbing intensity and broad bandwidth is an urgent demand to solve the electromagnetic pollution issues.An ideal microwave absorber should have excellent dielectric and magnetic loss capabilities,thereby inducing attenuation and absorption of incident electromagnetic radiation.Recently,various carbon/magnetic metal composites have been developed and expected to become promising candidates for high-performance microwave absorbers.In this review,we introduce the mechanisms of microwave absorption and summarize the recent advances in carbon/magnetic metal composites.Preparation methods and microwave absorption properties of carbon/magnetic metal composites with different components,morphologies and microstructures are discussed in detail.Finally,the challenges and future prospects of carbon/magnetic metal absorbing materials are also proposed,which will be useful to develop high-performance microwave absorption materials.
文摘After describing the characteristics of programming paradigm, this paper introduces the approach of code component composition reuse in detail, proposes and discusses viewpoint that code component composition reuse is a kind of new programming paradigm. This paper also specifies the characteristics of this new programming paradigm in detail, and points out some issues that must be resolved for using this new programming paradigm.
基金supports from the National Key Research and Development Plan(2020YFB1709401)the National Natural Science Foundation of China(11872138,11702048),Dalian Young TechStar Project(2019RQ045,2019RQ069)and the Scientific Research Fund Project of Education Department of Liaoning Province(JDL2020021).
文摘Fiber-reinforced composite materials have excellent specific stiffness,specific strength,and other properties,and have been increasingly widely used in the field of advanced structures.However,the design space dimensions of fiber-reinforced composite materials will expand explosively,bringing challenges to the efficient analysis and optimal design of structures.In this paper,the authors propose an explicit topology optimization method based on the moving morphable components for designing the fiber-reinforced material.We constrain the intersection area between components to guarantee the independence of each component and avoid the situation that one component is cut by other components.Adding the fiber orientation angle as a design variable,the method can optimize the structural layout and the fiber orientation angle concurrently under the given number of fiber layers and layer thickness.We use two classical examples to verify the feasibility and accuracy of the proposed method.The optimized results are in good agreement with the designs obtained by the 99-line code.The authors also popularize the proposed method to engineering structure.The results manifest that the proposed method has great value in engineering application.
文摘Hydrogen absorption composite powder of Mg incorporated with Ni and CrCl3 （88∶10∶2 in mass ratio） was prepared by reactive milling in hydrogen atmosphere. Hydriding/dehydriding performances were measured by self-made apparatus. The results show that reactive milling and multi-component addition of Ni and CrCl3 reduce the stability of hydride and improve the sorption performance of Mg-based materials. With powder milled for 60h, hydriding basically completes within 300s （250℃, 2.0MPa） and phase transformation fraction reaches 0.78. The phase transformation rate of hydriding/dehydriding progress increases significantly with the reduced particles size of powder while good kinetics of dehydriding at a relatively low temperature is gained with small grain size of hydride. Rapid temperature variations in a short span of time resulted from remarkable calorific effects of rapid phase transformation are detected in hydriding/dehydriding progress. The results of thermogravimetric and differential scanning calorimetric（TG/DSC） indicate that the onset temperature of desorption of composite milled for 100h is 272℃.
基金financial support by the National Natural Science Foundation of China(51474035).
文摘The saturate,aromatics,resin and asphaltene components of paraffin-base(PB)and naphthenic-base(HB)crude oil are separated by chromatographic column.The acidic components of crude oil are extracted by compounded polar solvents and identified by methyl esterification of diazomethane.The acidic components before and after asphaltene removal are investigated by gas chromatography-mass spectrometer.The effect of four fractions in simulated oil on interfacial activity is discussed.The results show PB is rich in naphthalene series and tri-aromatic steroids,and HB has a high content of phenanthrene series,chrysene series and methylpyrene,besides higher content of naphthalene series.The long carbon chain acids in HB oil decrease significantly by asphaltenes removal,confirming the presence of heavy oil acids in asphaltene.A little amount of saturates and aromatics in simulated oil can reduce the interfacial tension(IFT).When the content of asphaltenes of simulated oil is increased,IFT is initially decreased and finally increased because of stability of asphaltenes.When resin is increased,IFT is initially increased and then decreased.Simulated oil containing the resin from naphthenic-base oil is more sensitive to alkali than that of paraffin-base resin,which can reduce the IFT between oil and water at a larger range.
