Search

Stimuli-sensitive hydrogels crosslinked by macromolecular micelles usually present good mechanical properties. In this paper, a novel kind of pH and ion sensitive hydrogels with high toughness and strength were prepared using Pluronic F127 diacrylate (F127DA) as crosslinking centers for the free radical copolymerization of acrylamide (AM) and methacrylate (MA) monomers. These hydrogels showed high strength and tensibility with elongation at break of 1208%, fracture stress of 328 kPa and toughness of 1.80 MJ/m-3. The hydrogels not only exhibited enhancement of mechanical performance, but also achieved sensitive response to changes of pH and ionic strength, making an approach for the development of applications in drug delivery and sensors.

Polycarborane, as a kind of boron carbide polymeric precursor, was synthesized by hydroboration reaction with styrene, divinylbenzene as the carbon resource and borane as the boron resource in this work. The polymer precursor which had good solubility and film-forming ability was soluble in most organic solvents. Furthermore, polycarborane was used to fabricate hollow polymer microspheres by emulsion technique. The compact boron carbide ceramic hollow microspheres were prepared by ceramization of the polymer microspheres. Ceramic microspheres with diameters ranging from 1 to 1.5 mm and shell thicknesses from 15 to 30 μm were easily prepared by changing emulsion composition and curing conditions. Micrographs of SEM showed that the hollow microspheres had smooth surface and good sphericity. These boron carbide ceramic hollow microspheres are of significant importance for application in the field of neutron moderator in nuclear reactors, power generation in deep space flight, etc.

Iron-containing SiC ceramics have low specific resistivity and excellent electromagnetic properties. In this work, hyperbranched polyferrocenylsilane as the precursor of Fe/Si/C ceramics was prepared by the reaction of ferrocenyl dilithium, dichlorodimethylsilane and trichloromethylsilane. The ceramization process of the preceramic polymer from organic to inorganic was then investigated. Precursor microspheres were prepared by emulsion method, which were then pyrolyzed to obtain Fe/Si/C ceramic microspheres.The composition, structure and morphologies of the precursor and ceramics were characterized by 1H-NMR, FT-IR, TG-MS, XRD, SEM and EDS. Experimental results showed that the hyperbranched precursor was successfully synthesized, the pyrolytic process of which started at 350 °Cand almost completed above 600 °C. There was crystalline transformation from Fe5Si3 to Fe3Si as the sintering temperature increased from 1000 °C to 1400 °C. Moreover, the crystalline phase of β-SiC appeared at 1400 °C. Precursor microspheres were prepared by emulsion method. Porous ceramic microspheres were obtained after the precursor microspheres being sintered at 1400 °C, which can be applied in gas adsorption and catalyst supports.

Two kinds of iron-containing ceramic precursors, PFS and PS-b-PFS, were synthesized via living anionic polymerization by using ferrocenyldimethylsilane and styrene as the monomers. The structures, elemental compositions and molecular weights were characterized by FT-IR, NMR, EDS and GPC, respectively. The homopolymerization of ferrocenyldimethylsilane was simulated using computational chemistry method. The copolymerization between ferrocenyldimethylsilane and styrene was investigated by altering the ratio between monomers and initiator (n-butyllithium). The experimental results indicated that the Mn, Mw and PDi of homopolymer PFS were 6.91×103 g/mol, 8.29×103 g/mol and 1.20, respectively. Moreover, the molecular weight, structure and composition of block copolymers PS-b-PFS, were successfully controlled by changing the ratio of styrene, n-butyllithium and ferrocenyldimethylsilane. Subsequently, using such iron-containing polymers as precursors, Fe/Si/C ceramics were obtained after sintering at 1400°C. The microstructures, morphologies and elemental compositions of ceramics were characterized by SEM and EDS. The results implied the controllable preparation of spherical Fe/Si/C ceramics was achieved via the self-assembly of precursors.

In this work, the influences of composition and microstructure on the mechanical properties and thermal stability of SiC ceramic fibers were investigated. XPS, XRD, SEM, and element analysis were used to analyze the elemental composition and structural morphology. The contents of oxygen and free carbon influence the crystallinity of SiC fibers, which inhibit the grain growth of β-SiC. The reduction of tensile strength of the fibers sintered under temperatures above 1700°C is attributed to the appearance of massive defects on the outer surface of the fibers, which can be overcome by the change of sintering conditions of the pyrolysis fibers.

Results of preparing expandable graphite through Microwave Expansion method with the material of expandable graphite made through the Chemical Oxidation process show that in the temperature range of 700°C~900°C, the volume of expandable graphite will bigger with the rise of temperature, reaching the maximum 203 ml/g at the temperature of 900°C. The expandable graphite of 900°C can be modified in 0.5M hydrochloric acid; at the temperature of 40°C and 6h later, decolourization ratio of methyl orange will reach 95%. If the graphite is modified in concentrated nitric acid with the temperature of 50°C for 6 hours, the decolourization rate will be 96%. In terms of cost, it is more economical to modify expandable graphite in hydrochloric acid.

In this paper, TiO2/modified expandable graphite composite material was prepared through sol-gel method with the carrier of modified expandable graphite.The influence of this composite material prepared in different calcination environment and with different times of load on the effect of methyl orange solution’s photocatalytic degradation was studied. Results show that the photocatalytic effect is better by using the composite material with the same times of load in aerobic calcination than that in anaerobic calcination. In the same calcination environment, the photocatalytic effect with 5 times of load is better than that with 1, 2, 3 and 4 times of load. Whether in the aerobic calcination or in the anaerobic calcination, the photocatalytic effect is better if the composite material is loaded 5 times.

The high strength steel wire mesh and polymer mortar reinforcement technology has the advantages of high strength, high temperature resistance,corrosion,resistant, etc. In this paper,we analysis the flexural properties of RC beams strengthened by it using ANSYS.To bear the same moment in the same area of the reinforcement steel strand, and then get effect of different span and different reinforcement methods (comparative beam, direct reinforced beams,and secondary load of reinforced beams) on flexural load-carrying capacity and deflection, then compare and analysis,and draws the conclusion which can provide reference for practical engineering.

Stable TiO2 colloids composing of narrow size distrubuted anatase TiO2 nanocrystals were prepared using quaternary ammonium hydroxide, such as Me4NOH, Et4NOH and Bu4NOH, as catalyst. TEM and UV-Vis spectra measurements showed that the TiO2 colloids are quite stable in air or under ultrasound irradiation and the size of the TiO2 particles of the colloids can be tuned by changing the molar ratio of Titanium isopropoxide and the organic additive. The additive can be removed when the dried gel were calcined at 450°C for two hours, resulting in pure TiO2 nanocrystal in anatase phase.

Energy is an important strategic material basis for supporting the social development and the national economy, China has proposed the "12th Five-Year Plan" stressed the scientific concept of development must be implemented conscientiously, to build a resource-saving and environment-friendly society. How to choose a suitable energy development strategy for Hebei Province as a major agricultural province in China has important research value. This paper discusses the energy structure constraints on economic development and China's research trend of new energy,based on the prediction of energy consumption elasticity coefficient in Hebei Province and the analysis of comprehensive benefits of new energy, constructed the development system of new energy of Hebei Province in the regional economy, circular economy ,industrial chain and integrated perspective respectively, identifying the problems and breakthrough path for the implementation of new energy strategy in Hebei Province.

This paper presents a multi-robot cooperation strategy with virtual-physics force which includes three kinds of effort: structure formation force, goal force, and obstacle avoidant force. For swarm formation, a virtual robot is located at the center of the polygon. The innovative contribution of the strategy is that robots only having two kinds of forces: structure formation force and obstacle avoidant force while virtual robot having one kind of force: goal force. The motion of the virtual robot depends on the goal force which obtained from the sensor observations of the robots. Once the virtual robot moved to a new place, robots would also move with the forces acted on themselves as a single body and maintain a regular polygon formation. Simulation experiments are carried out, and the results show that the proposed strategy can effectively navigate the mobile robotics swarms to the chemical source in an indoor arena.

Using the finite element software ANSYS to analyze the CFRP strengthened concrete columns.The concrete columns are in the axial force existence situation, many columns should be reinforced by longitudinal and circumferential CFRP because of insufficient capacity. Subject to loading,11 root columns were designed, aiming to the layer number of CFRP, the location and orientation of CFRP, the eccentric distant of specimens.One of them is a non-reinforcement column.Under compression, bending, shearing and monotonic torsion, the nonlinear finite element model was established to test stressed steel bar in column test specimens, including longitudinal tensile reinforcement, longitudinal compression reinforcement and stirrup, as well as CFRP has been analyzed, including stress changing of longitudinal CFRP and transverse CFRP. The torque-strain curves for relationship were discussed among longitudinal reinforcement, stirrup and CFRP.

APMP high-consistency refining process is a complex energy-consuming process, under the unchanged condition of equipments, it’s very important to optimize the refining quality, yields and costs. Through analyzing the refining process, the mathematical model about optimizing three parameters simultaneously is proposed, and solved by the mathematical software with powerful function(LINGO), By comparing, the results show: for one thing, the different indices tendency determine the optimized degree; for another, the indices of quality and yields after optimization has been raised more than that before optimization, and the costs reduce obviously, the improvement of economic benefits is considerable for a larger enterprise.

A new kind of optical fiber corylic resin coating was prepared in this paper. The influence of PVC (pigment volume concentration) to the properties of coatings was studied. The best formula was selected. The best coating was painted on the optical fiber. The relationships of the coating diameter and the distances of the centers of the coating layer and optical fiber were studied. It was found that the circle diameter of coating is greater; the distance of centers of circles is bigger. Finally, the optical fiber with this coating was embedded in resin castings. The cross sections were observed under the same heated situation. The results revealed that the coatings embedded in composites used in large aircraft had no change when it was heated. This kind of coating did not need ultraviolet light or heating, and it’s easy to control the thickness and roundness of the coating by controlling the speed of pulling out the optical fibers. This type coating is a kind of simple heat-resistant coating embedded in composite materials used in the large aircraft.

This paper mainly investigates the effect of embedded optical fibers on the tensile prosperities of carbon fiber reinforced polymer-matrix composites (CFRPs). Different optical fibers are considered. The results show all the specimens are declining. And Optical Fiber (OF) with 245μm exhibit about 23.5% reduction.

Novel organic –inorganic nanocomposite hybrid materials have been prepared by a sol-gel process. Tetraethoxysilane (TEOS) was used as inorganic source. Polyurethane acrylate (PUA) was the organic segment. 3-(trimethoxysilyl)propyl methacrylate (KH-570) was used as both a secondary inorganic source and a silane coupling agent to improve the compatibility of the organic and inorganic phases. X-ray diffraction indicates that silica was equally dispersed in polymer matrix. Furthermore, silica and polymer formed interpenetrating polymer network. Thermal property of the hybrid materials were checked by TGA study.

Kernel function is dominant in regression process of Support Vector Machine (SVM), it influences the prediction performance of SVM directly. Single local or global kernel function has limitation in generalization or learning capacity. The mixture kernel function with two good capacities had been structured, and it had been used in soft-sensor modeling of refining process. The contrast of simulation results show: the generalization ability of SVM based on mixture kernel function is better than the ones based on the single local or global kernel function, the algorithm had been applied in the refining process of HETAO wood industry factory, and the prediction result meets the requirement of craft production.

The optical fibers with epoxy acrylates and urethane acrylates UV-curable coatings were embedded in composites. It’s found that after high-temperature heated, when the coating’s glass transition temperature was higher than the heating temperature, the microstructure of the coating would not change, but when the coating’s glass transition temperature was lower than the heating temperature, the coating would detached from optical fiber. FBG (fiber Bragg grating) sensors with coating and naked FBG (without coating) sensors were embedded in composite materials to monitor impacting damage. It was found that when the coating broke away from the optical fiber which was embedded in the composites, the sensitivity of the FBG sensors would reduce.

Fiber Bragg grating (FBG) sensors were applied for the monitoring of impact damage of composites. The FBG sensors were embedded into glass fiber reinforced vinyl resins (GFRP) laminates. Sectional appearance of the optical fiber embedded in composites was got by optical microscope. The composites were impacted by a drop-weight impact tester. The impact energies were 0.1J, 0.2J and 3J. The whole process was monitored by two different demodulators.

This paper mainly investigates the effect of embedded optical fibers on the tensile and bending propertities of cross-ply glass fiber reinforced plastics. Different optical fibers and different embedded layers are both considered. The results show nearly all the specimens are varying within a small region. But 3 OF at 0°embedded in bending specimens exhibit about 18.3% reduction, and the effect of 3 OF in the under layer is more than that of 3 OF in the upper layer.

Several different crystal types, different modified nano-TiO2 and conventional TiO2 were added into the coating to make some samples. A kind of nano-TiO2 which can improve the reflectivity effectively was selected. The effect of the nano--TiO2 content on the reflectivity and mechanical properties of the coatings.

we introduced a fast, specific, and sensitive sensing probe to detect Toxoplasma gondii DNA based on mechanism of fluorescence resonance energy transfer (FRET), and a multifunctional and magnetic-fluorescent CdTe/Ni quantum dots (mQDs) was prepared as energy donor, and BHQ2 was used as energy acceptor, respectively. CdTe/Ni mQDs were synthesized with a more simple method using Ni nanoparticles as core material and CdTe as shell material. The sensing probe was fabricated through labeling a stem-loop Toxoplasma gondii DNA oligonucleotide with CdTe/Ni mQDs at the 5′ end and BHQ2 at 3′ end, respectively, and the resulting sensing probe can be conveniently isolated and purified with a common magnet. Properties of mQDs and sensing probe were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), and fluorescence spectrum (FS) methods. The TEM data demonstrated that the size of Ni nanoparticles was estimated to be ~10nm, and size of CdTe/Ni is 15nm. XRD data showed similar spectrum of CdTe and CdTe/Ni, intensity of Ni (111) typical diffraction peak was detected, which inferred the formation of CdTe on surface of Ni core. An obvious fluorescence recovery (FR) was observed when the complete complimentary target Toxoplasma gondii DNA was introduced comparing with the target DNA with one-basepair-mismatch, this result revealed the sensing probe has high sensitivity and specificity. The current sensing probe will has great potential applications in the life science and gene diagnostics.

We presented a fast, specific, and sensitive DNA sensing system, which composed of a CdTe/Fe3O4 magnetic core-shell quantum dots (energy donor), a commercial quencher (BHQ2; energy acceptor), and a designed single strand Toxoplasma gondii DNA. The designed single strand Toxoplasma gondii DNA was applied to link the energy donor and acceptor, and target DNA was detected based on mechanism of fluorescence resonance energy transfer. The CdTe quantum dots, Fe3O4 magnetic nanoparticles, CdTe/Fe3O4 magnetic core-shell quantum dots, and sensing probe were step-wisely prepared. Properties of synthesized quantum dots were investigated by transmission electron microscopy, fluorescence spectrum, nano zeta potential and submicron particle size analyzer, and X-ray diffraction, respectively. Specificity and sensitivity of sensing probe was determined by measuring the recovery of fluorescence intensity. The obtained sensing probe with magnetic properties can be simply separated or concentrated from the hybridized solution with a common magnet. The resulting data revealed the sensing system was successfully fabricated, and which has high sensitivity and specificity.

A novel CdTe/Ni QDs which combined both magnetism and fluorescence was successfully synthesized and its optical properties were investigated. Ni magnetic nanoparticles (MNPs) were synthesized and used as magnetic core, CdTe quantum dots (QDs) were applied as fluorescent shell material, the qualified magnetic CdTe/Ni quantum dots (mQDs) were achieved via layer-by-layer process using 1,6-hexylenediamime as linker, surface charge types of MNPs and mQDs were confirmed with a delsa nano beckman coulter. Morphology of the prepared Ni MNPs and CdTe/Ni mQDs was characterized by transmission electron microscopy (TEM), and optical properties were investigated with fluorescence spectrum (FS). Qualified CdTe/Ni mQDs with high fluorescence and narrow maximum emission peak width were obtained under the optimum conditions. Surface zeta-potential of CdTe QDs and Ni MNPs were estimated to be -36.2 and 27.97mV, respectively. TEM data indicated that ca 20nm of Ni MNPs and ca 25nm of CdTe/Ni mQDs were prepared, respectively; the size-increasing indicated the formation of CdTe shell on the Ni MNPs core. Narrow half peak width of emission peak was detected and calculated to be about 50nm via FS. High fluorescence intensity of CdTe/Ni mQDs was determined and brilliant yellow solution was observed when excited under UV360nm. The synthesized CdTe/Ni mQDs showed excellent magnetic property, and can be magnetically concentrated with a common magnet. The obtained data indicated that the prepared bi-functional CdTe/Ni mQDs possess excellent magnetic and fluorescent properties, and it can be used as a energy donor in DNA sensing based on fluorescence resonance energy transfer (FRET).