Materials,preparation,performances and mechanism of polyurethane modified asphalt and its mixture:A systematic review

With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.

Preparation of Dashanzha Wan by three-dimensional printing

Objective:To use three-dimensional(3D)printing technology to prepare Dashanzha Wan.Methods:The standard formula proportion of Dashanzha Wan was used to prepare printable materials(normally called the ink)for 3D printing,and different doses and shapes of Dashanzha Wan were prepared.Then,the rheological properties,texture characteristics,scanning electron microscopy,and content of ursolic acid were evaluated.Results:Dashanzha Wan ink showed good shear thinning properties,which is very suitable for 3D printing.The printed sample had a beautiful and regular shape with high resolution.Meanwhile,ursolic acid content in 3D-printed Dashanzha Wan aligned with the ursolic acid content shown in the Pharmacopoeia of the People's Republic of China 2020.Conclusion:The 3D-printed Dashanzha Wan has a better texture,and can be shaped into various shapes according to individual needs,which would increase patients’interest when taking medicine.Moreover,3D printing of Dashanzha Wan could be easily integrated into the digital life system,enabling online customization or use at home.This study reveals that 3D printing technology is a promising method for the production of traditional Chinese medicine with personalized appearance,dosage,and texture,which is suitable for a broader population.

Ultra-high Temperature Ceramic Coatings:A Review on Preparation Technology and Development Prospect

Ultra-high temperature ceramic coatings have ultra-high melting points,excellent mechanical properties and high temperature ablation resistance.These unique performance combinations turn it into a promising material for use in extreme environment structures in rockets and hypersonic vehicles,particularly nozzles,leading edges and engine components.In this paper,various preparation methods of ultra-high temperature ceramic coatings were reviewed,including plasma spraying,chemical vapor deposition,pack cementation,slurry sintering,hot pressing and their research progress.Meanwhile,some new preparation methods of high temperature coatings,such as ion beam deposition,ultrasonic spraying,metal organic frame work coating,and magnetron sputtering,were introduced.The development trend of ultra-high temperature coatings was prospected as well.

Preparation Process and Thin Layer Chromatography Identification of Wufang Babu Poultice

[Objectives] To establish the process flow of preparation of Wufang Babu Poultice and the identification method of thin layer chromatography (TLC). [Methods] For the forming process of Wufang Babu Poultice, the preparation method of mixed pharmaceutical powder with suitable pharmaceutical excipients was adopted. Qualitative identification of medicinal materials in Wufang Babu Poultice (Strychni Semen, Rhei Radix Et Rhizoma, Dipsaci Radix, and Angelicae Sinensis Radix) was carried out by TLC. [Results] Mixed pharmaceutical powder mixed with glycerol, gelatin and other pharmaceutical excipients can be prepared for forming. The test solution chromatography of each medicinal material (Strychni Semen, Rhei Radix et Rhizoma, Dipsaci Radix, Angelicae Sinensis Radix) showed pigment spots of the same color at the same position as its corresponding control medicinal materials and reference chromatography, and the display was clear. [Conclusions] The preparation process is simple and feasible, and can be used as the forming process of Wufang Babu Poultice. The TLC determination method is simple to operate, has good specificity, and has no effect on negative results, and can be used for identification of Wufang Babu Poultice.

Preparation Process of Plumbagin Nanomicelle In-situ Gel

[Objectives]To prepare plumbagin nanomicelle(PLB-N)in-situ gel,and optimize the formulation and process.[Methods]PLB-N was prepared by self-assembly method,and the optimal formulation of PLB-N in-situ gel was determined by orthogonal experiment design and single factor method.[Results]The optimal preparation process for PLB-N was a drug to lipid ratio of 1:3,a Tween 80 content of 5%,an ethanol content of 7.5%of the hydration medium,a magnetic stirring speed of 2200 rpm,a stirring time of 30 min,and an ultrasound time of 10 min.The optimal formulation of PLB-N in-situ gel was 22%of poloxamer 407,6%of poloxamer 188,and 1:1 of PLB-N to water.The encapsulation efficiency of PLB-N prepared with the optimal formula was(95.8%±0.4%),and the average particle size was(75.19±1.14)nm,and the Zeta potential was(-20.73±1.19)mv.[Conclusions]PLB-N in-situ gel had stable and reliable preparation process,uniform content,and broad application prospects.

Preparation of Perovskite-Type Oxides La_(1-x)Sr_xFe_(1-y)Co_yO_3 Using EDTA Sol-Gel Method

Two series of perovskite-type oxides with composition (La_(1-x))Sr_xFeO_3(x≤0.8)and La_(1-x)Sr_xFe_(1-y)Co_yO_3(x=0.2; y=0.2, 0.4)powder productions were synthesized by EDTA complexing sol-gel method. The products were characterized by XRD, TEM, SEM, BET method(N_2 adsorption)and laser granularity analysis for different synthesis conditions to obtain the optimum conditions for the preparation process. Single-phased, uniform perovskite-type oxides with small particle size were obtained by EDTA sol-gel process with high stability and repeatability, and the process temperature is much lower than that of solid state reaction method.

3D Modeling of the preparation process of metal rubber material

Based on the analysis of the preparation of metal rubber （MR） and two pivotal hypotheses, the uniform distribution and the unaltered topological structure of wires in the radial direction of columns in the punch process, a 3D parametrical model was established based on four approaches： helix-making, planar roughcast-weaving, planar roughcast-rolling, and 3D roughcast punching. In the modeling process, 5 lattice types of weave patterns in planar roughcast were put forward, and 10 quantificational modeling parameters were picked up to exclusively define the column MR component structure. The wire distribution was visualized by CAD techniques. The important performance parameter of column MR components （relative density ρ^- ） can be forecasted by modeling computing, which provides the necessary foundation for the design and optimization of MR materials.

Modelling of vehicle interaction behavior during discretionary lane-changing preparation process on freeway

In order to increase the accuracy of microscopic traffic flow simulation,two acceleration models are presented to simulate car-following behaviors of the lane-changing vehicle and following putative vehicle during the discretionary lanechanging preparation( DLCP) process, respectively. The proposed acceleration models can reflect vehicle interaction characteristics. Samples used for describing the starting point and the ending point of DLCP are extracted from a real NGSIM vehicle trajectory data set. The acceleration model for a lanechanging vehicle is supposed to be a linear acceleration model.The acceleration model for the following putative vehicle is constructed by referring to the optimal velocity model,in which optimal velocity is defined as a linear function of the velocity of putative leading vehicle. Similar calibration,a hypothesis test and parameter sensitivity analysis were conducted on the acceleration model of the lane-changing vehicle and following putative vehicle,respectively. The validation results of the two proposed models suggest that the training and testing errors are acceptable compared with similar works on calibrations for car following models. The parameter sensitivity analysis shows that the subtle observed error does not lead to severe variations of car-following behaviors of the lane-changing vehicle and following putative vehicle.

Study on Preparation Process of Effervescent Tablets Made from EGCG of Tea

[ Objectivel The study aimed to discuss the preparation process of Epigallocatechin-3-gallate （EGCG） effervescent tablets. [ Method] Various raw materials were dried for different time at 50℃, and then the sticking degree of EGCG effervescent tablets was reviewed. Hereafter, the formula of EGCG effervescent tablets was optimized by orthogonal test. [ Result] Effervescent tablets without sticking were smooth after being dried for 150 rain. The optimal formula of EGCG effervescent tablets was composed of 4% EGCG, 45% citric acid and sodium carbonate （Citric acid： Sodium carbonate = 1.6：1 ）, 20% lactose, 4% L-leucine, 4% sodium cyclamate and 23% orange powder. [Condusion] The prepared EGCG effervescent tablets without sticking has a good effervescence effect and taste.

Research progress on preparation technology of oxide dispersion strengthened steel for nuclear energy

Nuclear energy is a low-carbon,safe,efficient,and sustainable clean energy.The new generation of nuclear energy systems operate in harsher environments under higher working temperatures and irradiation doses,while traditional nuclear power materials cannot meet the requirements.The development of high-performance nuclear power materials is a key factor for promoting the development of nuclear energy.Oxide dispersion strengthened(ODS)steel contains a high number density of dispersed nano-oxides and defect sinks and exhibits excellent high temperature creep performance and irradiation swelling resistance.Therefore,ODS steel has been considered as one of the most promising candidate materials for fourth-generation nuclear fission reactor cladding tubes and nuclear fusion reactor blankets.The preparation process significantly influences microstructure of ODS steel.This paper reviews the development and perspective of several preparation processes of ODS steel,including the powder metallurgy process,improved powder metallurgy process,liquid metal forming process,hybrid process,and additive forging.This paper also summarizes and analyzes the relationship between microstructures and the preparation process.After comprehensive consideration,the powder metallurgy process is still the best preparation process for ODS steel.Combining the advantages and disadvantages of the above preparation processes,the trend applied additive forging for extreme manufacturing of large ODS steel components is discussed with the goal of providing a reference for the application and development of ODS steel in nuclear energy.

Preparation of DyFe_2 by the Reduction-Diffusion Process

The free energy change for the reduction-diffusion reaction which was used to prepare the DyFe_2 D_y2 O_3(s) + 3Ca(g) + 4Fe(s) = 3C_aO(s) + 2D_yFe_2(s) intermetallic compound powder was calculated. The reduction-diffusion experiments were carried out at 1073, 1123. 1273 and 1373 K respectively using powders of D_y2O_3, iron, and calcium grains as raw materials. XRD and EDX analysis confirmed that D_yFe_2 was formed by the diffusion of Dy into Fe.

Preparation and Characterization of Semi-Metal Friction Materials Doping Rare Earths

In order to study the effects of preparation process on the performance and microstructure of the materials, semi-metal friction materials doping rare earths were produced. Different influencing factors in preparation processes (forming pressure, hot-pressing temperature, etc.) were investigated and the optimum technological parameters were selected. The results showed that preparation processes has correlation with the properties of the materials. The morphology of worn surface was observed by scanning electronic microscope, and the conclusion was drawn that wear mechanisms of the materials were mainly abrasive wear, adhesive wear and fatigue wear. Doping RE in the materials can improve the interfacial bonding among the components of semi-metal friction materials and make the structure of the materials more impact.

Study on Preparation Process and Quality Standard of Tianlu Tongluo Granules

[Objectives]This study was conducted to optimize the preparation process of Tianlu Tongluo Granules and establish its quality standard.[Methods]Tianlu Tongluo Granules was prepared by an orthogonal test.TLC was used to identify Radix Astragali preparata,Radix Paeoniae Alba,Scutellariae Radix and Acori Tatarinowii Rhizoma in the granules,and the content of paeoniflorin in the finished product was determined by HPLC.[Results]The extraction process of Tianlu Tongluo Granules was as follows:adding 6 times of water,and decocting twice,1 h/time.In the forming process,the optimal ratio of thick paste to excipients as 10∶8.6,and the optimal ratio of excipients dextrin:starch:colloidal silicon dioxide was 6.5∶0.5∶1.6.The results showed that TLC spots were obvious,the separation was significant,and the specificity was strong.The paeoniflorin content had a good linear relationship in the concentration range of 5.9048-590.48 mg/L(r=0.9999).The average sample recovery was 101.10%,and the RSD was 1.18%.[Conclusions]The preparation process is stable and reasonable,and the established quality control method is specific and reproducible,and can be used for the quality control of Tianlu Tongluo Granules.

Preparation and Performance of CdZnTe Ray Detector

γ-ray and x-ray detectors made by Cd1-xZnxTe alloy can gain high energy resolution and detect efficiency at room temperature due to its high atomic number,large energy gap and high density,which were well-developed recently.By well controlled of Cadmium partial pressure and compensatory doping technique,Ф90 mm Cd1-xZnxTe alloy obtained successfully(ρ≥1011Ω·cm)by an improved-Bridgman method.3 mm×3 mm×3 mm CZT de­tector was made at Kunming Institute of Physics,which has energy resolu­tion of 3.52%(FWHM)at room temperature when detect 59.54 KeV Am241γ-ray source.

Stress corrosion cracking of magnesium alloys:A review

Magnesium(Mg)alloys have been widely used in automobile,aviation,computer,and other fields due to their lightweight,high specific strength and stiffness,low pollution,and good electromagnetic shielding performance.However,the chemical stability of Mg alloys is poor,especially in the corrosive medium environment with high stress corrosion sensitivity,which causes sudden damage to structural components and restricts their application field.In recent years,owing to the increasing failure rate of engineering structures caused by stress corrosion of Mg alloys,it has become necessary to understand and pay more attention to the stress corrosion cracking(SCC)behavior of Mg alloys.In this paper,the SCC mechanisms and test methods of Mg alloys have been summarized.The recent research progress on SCC of Mg alloys has been reviewed from the aspects of alloying,preparation process,surface modification,corrosive medium,and strain rate.More importantly,future research trends in the field of SCC of Mg alloys have also been proposed.

Advances in Research of Epidemic Lung Preventive Mixture

This paper summarizes the Epidemic Lung Preventive Mixture from three aspects of research status, development trends and prospects, so as to deepen the understanding of Epidemic Lung Preventive Mixture and provide a more detailed theoretical basis for its further clinical research and development.

Establishment and evaluation of O/W type-based microemulsion on crossbow medicine of the Miao ethnic group

Background:Crossbow medicine needle is a traditional external therapy.However,acupuncture pain,inaccurate administration,secondary infection,and poor patient compliance limit the application of specialty therapies.Since the most effective components of crossbow medicine are lipid-soluble,the crossbow medicine needle was prepared as an innovative O/W-type microemulsion to solve these problems.In this study,the crossbow medicine microemulsion preparation method was established and its quality was evaluated.Methods:A single factor and pseudoternary phase diagram,combined with a D-optimal mixture design,optimized the formulation of crossbow medicine microemulsion through particle size,polydispersity index,zeta potential,microstructure,and contents of benzoyl neoaconitine,benzoyl hypoaconitine,neoaconitine,periplocin,and methyl salicylate to evaluate the final prescription.Results:The best prescription for preparing crossbow medicine microemulsion is 0.1500 g crossbow medicine dry extract,0.1500 g isopropyl myristate,0.8625 g polyoxyethylene castor oil-35,0.2875 g ethanol,3.700 g water,and 5.1500 g microemulsion.The prepared microemulsion is an oil-in-water type with a clear and transparent appearance.Its average particle size is 19.83±0.78 nm,average polydispersity index is 0.15±0.02,and average zeta potential is−0.51±0.1 mV.The pH value is 5.17±0.02.The microstructure of crossbow medicine microemulsion illustrated a uniform distribution of spherical oil globules.The average contents of benzoyl neoaconitine,benzoyl hypoaconitine,neoaconitine,periplocin,and methyl salicylate were 13.34,113.05,43.45,628.27 and 27.93μg/g,respectively.Conclusion:The preparation process of crossbow medicine microemulsion is reasonable and feasible.The method to determine the content is accurate and straightforward,laying the foundation for further research.

Ti/Al_2O_3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one