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The optimization of the turbocharger structure can significantly improve its properties. In order to establish the dynamic coupling formula, the blade was simplified as a thin flexible rectangular plate moving in space, and the Lagrange dynamic equation was used to solve the problem. At the same time, the ANSYS analysis shows that the mode conversion and frequency conversion are ubiquitous and have certain influence on the life of compressor impeller. A new kind of curved leading edge with wide chord sweepback blade is presented, and proves that compared with the old blade, the stress and fatigue fracture are relived.

Failure analysis and fatigue life prediction are important steps in the design procedure of industrial products to assure the safety and reliability of their components. A new methodology t...

We investigated the effects of one-dimensional shock wave compression on the structural, dielectric, and ferroelectric properties of a potassium niobate ferroelectric crystal using Landau–Ginsburg–Devonshire phenomenological theory. Our results show that the cubic to tetragonal and tetragonal to orthorhombic phase transition temperatures increase with increasing shock compression and the derivative of the phase transition temperatures with respect to stain induced by shock compression was estimated to be 21.9 °C/10−3. Additionally, the orthorhombic to rhombohedral phase transition temperature decreased with increasing shock compression and the derivative of the phase transition temperatures with respect to stain induced by shock compression was estimated to be −144.3 °C/10−3. This result represents a 15.3% increase in the remnant polarization of the tetragonal KNbO3 crystal when the stain induced by shock compression increased from 0 to 4 × 10−3 at 400 °C. The dielectric susceptibilities e33 and e22 were calculated to decrease by approximately 20% and 40%, respectively, when the stain induced by shock compression increased from 0 to 1.6 × 10−3 at 350 °C. The increase in the remnant polarization and the decrease in the dielectric properties induced by shock compression provide an effective way to improve the power output capacity of a ferroelectric-pulsed power supply.

Humidity sensors are playing more and more important roles in the fields of modern industry, agriculture, food production and storage, medicine as well as in our daily life. To satisfy the increasing technical requirements such as high sensitivity, short response and recovery time and measurement reproducibility, much effort has been devoted to developing novel sensing materials. In recent years, nanocomposite humidity-sensing materials have aroused much attention because of their high performances. In the paper, we report the preparation and capacitive humidity-sensing properties of a ZnO nanorod bundling array grown on silicon nanoporous pillar array (ZnO/Si-NPA), and those of a LiCl-incorporated ZnO/Si-NPA (LiCl:ZnO/Si-NPA). It was demonstrated that compared with ZnO/Si-NPA, the integral humidity sensing properties of LiCl:ZnO/Si-NPA were promoted significantly. The underlying mechanism was probed by measuring and analyzing the behavior of the capacitance variation with frequency at different RH levels. These results demonstrated that LiCl:ZnO/Si-NPA might be a promising material system for fabricating humidity sensors with high-performances.

Persistent local oxygen delivery is crucial to create a microenvironment for cell survival and nerve regeneration in acute spinal cord injury (SCI). This study aimed to fabricate calcium peroxide-based microspheres incorporated into a 3-D construct scaffold as a novel oxygen release therapy for SCI. The scaffolds were able to generate oxygen over the course of 21 days when incubated under hypoxic conditions. In vitro, GFP-labeled bone marrow-derived mesenchymal stem cells (MSCs) were planted into the scaffolds. We observed that scaffolds could enhance MSC survival under hypoxic conditions for more than 21 days. Oxygen generating scaffolds were transplanted into spinal cord injury sites of rats in vivo. Twelve weeks following transplantation, cavity areas in the injury/graft site were significantly reduced due to tissue regeneration. Additionally, the oxygen generating scaffolds improved revascularization as observed through vWF immunostaining. A striking feature was the occurrence of nerve fiber regeneration in the lesion sites, which eventually led to significant locomotion recovery. The present results indicate that the oxygen generating scaffolds have the property of sustained local oxygen release, thus facilitating regeneration in injured spinal cords.

Utilizing silicon nanoporous pillar array (Si-NPA) as substrate, a kind of CdS/ZnO sesame-seed-candy structure was prepared by successively growing ZnO nanorods and CdS nanograins via chemical vapor deposition and successive ion layer adsorption reaction method, respectively. The capacitive humidity sensing properties of CdS/ZnO/Si-NPA were studied by constructing coplanar interdigital electrodes. With the relative humidity (RH) increasing from 11% to 95%, a capacitance response over 201,530% was achieved, which indicates that CdS/ZnO/Si-NPA is highly sensitive to humidity. The response and the recovery times were determined to be ∼110 s and 32 s, respectively, with a maximum hysteresis being ∼2.67% at 75% RH. The high humidity sensitivity of CdS/ZnO/Si-NPA is attributed to the enlarged specific surface area induced by its unique nanostructure, while the short response/recovery times and the small hysteresis were due to the channel network brought by Si-NPA. These results indicate that CdS/ZnO/Si-NPA might be an ideal material system for fabricating high-performance humidity sensors.

Weather-strip seals in automotive door systems play a major role in determining the door closing effort, isolating the passenger compartment from water and reducing the wind noise inside the vehicle. The phenomenon of a wrinkle often occurs in weather-strips when they are assembled on the door surfaces which have bent or twisted profiles. Wrinkles in automobile weather-strip seals will affect the closing effort and noise isolation characteristics of the automotive door system. The wrinkle of anethylene-propylene-diene (EPDM) automobile weather-strip seals when bent and the critical conditions for a wrinkle to develop were characterized in this study. The hyperelastic material behavior of the EPDM sponge and EPDM dense rubber in the seal were modeled using the Foam model and Mooney–Rivlin model, respectively. Then a finite element analysis (FEA) model of the automobile weather-strip seal in assembly was developed and analyzed using then on linear FEA software Marc. The deformation of the seal and t...

The extensive application of humidity sensors has greatly stimulated the study on high-performance humidity-sensing materials. In the paper, we report that a prototype humidity sensor was prepared by growing cadmium sulfide (CdS) on silicon nanoporous pillar array (Si-NPA) through a successive ionic layer adsorption and reaction method followed by immersing the samples in the solution of lithium chloride (LiCl). It was demonstrated that through the immersion treatment, the humidity-sensing properties including the response and its linearity, response and recovery time, hysteresis, and measuring reproducibility and stability were improved significantly. These results indicated that LiCl-immersed CdS/Si-NPA might be a promising material for fabricating humidity sensors applied to medium and low humidity range.

A new method for adjusting the tool rake and flank angles by changing the position of the tools was used to dynamic explore the nano-cutting behavior of single-crystal silicon using MD simulation. Simulations under the same cutting conditions were carried out using a tool swinging to six different rake angles of − 10°, − 15°, − 20°, − 25°, − 30°, − 35°, and − 45°. The advantages of Tersoff potential function are discussed in comparison with those of using SW potential function. The coordination number, von Mises stress, hydrostatic stress, system temperature, potential energy and cutting force during the nano-cutting process are studied. The results of a statistical study reveal that the coordination numbers of silicon atoms showed a minimum value and the highest average hydrostatic stress at − 25° adjustment angle. Besides, the maximum system potential energy and temperature is also obtained at an adjustment angle of − 25° after − 20° (it can be defined as a larger adjustment angle after − 15°). In addition, the results also point out that the highest average tangential force was observed at − 25°, which is different from the previous researches.

Austenitic stainless steel butt joints are widely used in the pressure piping system, and the quality of welded joints directly affect the safety of pressure special equipment. In this paper, phased array ultrasonic testing technology is used to study the feasibility of 4mm∼10mm wall thickness workpiece. Through the software CIVA (Developed by The French Alternative Energies and Atomic Energy Commission (CEA)) simulat to determine the parameters of the detection system, and it tests the 18 groups of 4mm∼10mm series simulation samples by PAUT (Phased Array Ultrasonic Testing).Through comparison with Radiographic testing, PAUT for the girth weld can be effectively for the 4mm∼10mm Austenitic Stainless Steel Pipeline.

Due to the Small diameter and thin walled tube docking girth joint ultrasonic testing has the problems of: dead zone is often greater than the wall thickness; large curvature of the pipeline causes ultrasonic scattering, greatly reduces the sensitivity; pipe weld root’s is not welded and so on. In this paper, the prepared small-bore and sheet steel tube docking girth joint ultrasonic testing probe has sufficient sensitivity, is less than 2.5mm of initial pulse width, short front (≤ 5mm), high resolution, less clutter, less surface wave components, At the same time, the test block was designed and used for the testing of probe’s related technical indicators, the test block can meet the focus probe’s performance and scanning sensitivity calibration. Combined with the field detection and compared with the radiographic testing, the ultrasonic testing obtain good result. It is suitable for the ultrasonic quantitative testing of the joint ring weld of thin wall pipe.

This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed, which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements. Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means (− 6980 to − 3651 pcm) and negative temperature coefficient (− 6.32 to − 3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient, have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including 6Li depletion and tritium production.

An ultra-wide-angle THz metamaterial absorber (MA) utilizing sixteen-circular-sector (SCR) resonator for both transverse electric (TE) and transverse magnetic (TM) mode is designed and investigated numerically. At normal incidence, the absorptivity of the proposed MA is higher than 93.7% at 9.05 THz for different polarization angles, due to the rotational symmetry structure of the unit cell. Under oblique incidence, the absorptivity can still exceed 90%, even when the incident angle is up to 70° for both TE and TM mode. Especially, the frequency variation in TE mode is less than 0.25% for different incident angles from 0° to 70°. The electric field (Ez) distributions are used to explain the absorption mechanism. Numerical simulation results show that the high absorption with wide-angle independence stems from fundamental dipole resonance and gap surface plasmons. The broadband deep-infrared MA is also obtained by stacking three metal-dielectric layers. The designed MA has great potential in bolometric pixel elements, biomedical sensors, THz imaging, and solar cells.

Thorium blanket fuel is investigated in Pebble Bed Fluoride salt-cooled High temperature Reactor (PB-FHR) with 19.9 at% U-235 seed fuel to improve the utilization of uranium fuel. Uranium fuel utilization is optimized with lots of parameters, such as graphite-to-thorium atom ratio (C/Th), graphite-to-uranium atom ratio (C/U), discharge burnup of thorium and uranium, and the dimension of the seed/blanket region. It is found that the equivalent discharge burnup, defined as total released energy over the mass of uranium, could be improved to around 265 MWd/kgU, which is 20% higher than discharge burnup using pure uranium fuel. In equilibrium state, the temperature reactivity coefficients of fuel and coolant are both negative. Other properties such as radial power peak factor, life of reflector, in-pile residence time of thorium pebble and radioactive waste are analyzed. Finally, baseline design parameters are recommended for further thermal-hydraulic analysis and TRISO fuel performance. (C) 2015 Elsevier Ltd. All rights reserved.

The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the SiC particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the SiC particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the SiC particles accumulate at the bottom of the shell. The volume fraction of SiC decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m−1·K−1, the coefficients of thermal expansion (CTE) are 8.2×10−6 and 12.6×10−6 K−1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.

Fluoride salt-cooled high-temperature reactors (FHRs) include many attractive features, such as high temperature, large heat capacity, low pressure and strong inherent safety. Transient characteristics of FHR are particularly important for evaluating its operation performance. Thus, a specialized code OCFHR (operation and control analysis code of FHR) issued to study an experimental FHR’s operation behaviors. The geometric modeling of OCFHR is based on one-dimensional lumped parameter method, and some simplifications are taken into consideration during simulation due to the existence of complex structures such as pebble bed, intermediate heat exchanger (IHX), air radiator (AR) and multiply channels. A point neutron kinetics model is developed, and neutron physics calculation is needed to provide some key inputs including axial power density distribution, reactivity coefficients and parameters about delayed neutron precursors. For analyzing the operational performance, five disturbed transients are simulated, involving reactivity step insertion, variations of coolant mass flow rate of primary loop and intermediate loop, adjustment of air inlet temperature and mass flow rate of air cooling system. Simulation results indicate that inherent self-stability of FHR restrains severe consequences under above transients, and some dynamic features are observed, such as large negative temperature feedbacks, remarkable thermal inertia and high response delay.

Fluoride salt cooled High temperature Reactor (FHR) is a kind of Gen-IV reactor which possesses many attractive features, such as high temperature, low pressure etc. Thermal-hydraulic features of molten salt are different from coolants of traditional reactors, which dominate operation transient behavior of FHR. However, as a new type reactor with sphere fuel element and fluoride salt coolant, FHR has inadequate operating experience and data used for reactor control and the design of power regulating system. Therefore, research of power regulation strategy is very important for FHR in automatic control operation and commercial application. A code programmed in Fortran platform is used for investigating the system transient behavior, control logic and strategy. Based on the transient analysis code OCFHR for FHR, power control logic strategy is studied on a model of 10 MW Fluoride salt cooled High Temperature Experiment Reactor. OCFHR is a specialized code in FHR transient analysis, which contains point reactor model, simplified core thermal-hydraulic model, molten salt-salt exchanger and molten salt-air exchanger with a tube-shell type, control rod system and power regulation and control model. The control module of OCFHR uses the incremental PID controller to regulate control parameters and adopts the compound mode of control rod adjustment, load adjustment and molten salt flow adjustment, so that it can adjust the control rod position, primary and secondary molten salt flow rate and air flow rate of load at different operating power levels. Two kinds of steady operation strategies are studied in this paper, which are a) constant outlet coolant temperature and b) constant average coolant temperature. The power level is regulated by control rod while the working temperatures are adjusted by shifting the load with weight coefficients of power and temperature deviations. The results show that the incremental PID controller with optimized parameters can achieve the control requirement. Both of temperature control strategies gain great performances under 10%FPand 50%FP power regulation. The target power is reached quickly and accurately by using the incremental PID controller while the temperature control is very time-consuming. Compared with b), strategy a) has less temperature overshoot but larger power overshoot and longer adjusting time. The step wise power regulation for FHER is doable when a wide power adjustment range is needed and the simulation 10%FP treated as a step works well. Besides, the preliminary study of varying secondary coolant flow rate also indicates that the secondary loop plays an important part in restraining the deviation of secondary coolant temperatures during the process of balancing the power and load, so it is better to adjust the secondary coolant flow in terms of the power regulation range.

The electronic packaging shell of high silicon carbide (54%SiC, volume fraction) aluminum-based composites was produced by liquid–solid separation technique. The characteristics of distribution and morphology of SiC as well as the shell's fracture surface were examined by optical microscopy and scanning electron microscopy, and the thermo-physical and mechanical properties of the shell were also tested. The results show that Al matrix has a net-like structure while SiC is uniformly distributed in the Al matrix. The SiC p /Al composites have a low density of 2.93 g/cm 3 , and its relative density is 98.7%. Thermal conductivity of the composites is 175 W/(m·K), coefficient of thermal expansion (CTE) is 10.3×10 −6 K −1 (25–400 °C), compressive strength is 496 MPa, bending strength is 404.5 MPa, and the main fracture mode is brittle fracture of SiC particles accompanied by ductile fracture of Al matrix. Its thermal conductivity is higher than that of Si/Al alloy, and its CTE matches with that of the chip material.

In order to investigate the match between the nozzle tip penetration and the double-layers diffluent combustion chamber geometry, a simulation model was developed which was based on the 135 diesel engine to simulate the equivalence ratio distribution of air-fuel mixture and the temperature distribution during combustion process. At the same time, an experiment was executed by a 135 diesel engine equipped with the high-pressure common rail fuel injection system. The research results show that the air-fuel mixture becomes more uniformed and the combustion process is improved when the nozzle tip penetration is reasonable selected which lead to higher in-cylinder pressure and better brake specific fuel consumption while NOXemission is increased and soot emission is decreased for the double-layers diffluent combustion system.

Two transmission curved crystal spectrometers are designed to measure the hard x-ray emission in the laser fusion experiment of Compton radiography of implosion target on ShenGuang-III laser facility in China. Cylindrically curved ${\it\alpha}$ -quartz (10–11) crystals with curvature radii of 150 and 300 mm are used to cover spectral ranges of 10–56 and 17–100 keV, respectively. The distance between the crystal and the x-ray source can be changed over a broad distance from 200 to 1500 mm. The optical design, including the integral reflectivity of the curved crystal, the sensitivity, and the spectral resolution of the spectrometers, is discussed. We also provide mechanic design details and experimental results using a Mo anode x-ray source. High-quality spectra were obtained. We confirmed that the spectral resolution can be improved by increasing the working distance, which is the distance between the recording medium and the Rowland circle.

The experiments of high speed milling Ni-base superalloy GH625 by using two types of the coated cemented carbide tools at home and abroad, using the scanning electron microscopy (SEM) to observe the tools wear morphology, analyzing the worn surface elements distribution by energy spectrum analysis (EDS) and the main wear mechanisms of the tools. The results show that adhesion, oxidation and diffusion are the main wear mechanisms in initiative wearing stage of the domestic coated tools. And the main wear mechanisms of the imported coated tools are adhesion, oxidation, diffusion and coating spallation.

Isotropic pyrolytic graphite is a kind of graphite material. Because of its excellent performance, it is gradually used in aero-engine turbine shaft seals. But this material is a kind of brittle material, and it wears seriously during the cutting process. Through analysis of the process of cutting this material with PCD insert, the main wear region and the wear pattern at different cutting time were obtained. Using the scanning electron microscopy to observe the wear regions, the wear mechanism of PCD was obtained. At the first stage of the wear mechanisms were mainly mechanical wear and abrasive wear, the main wear regions were rake face and the cutting edge. With the increase of cutting distance, about 32 min later, both the depth of the crater on the rake face and the depth of micro grooves on the flank face were increased. Abrasive wear on the cutting face and the micro grooves wear on the flank face were the main wear pattern at the stable wear stage. At rapid wear stage, cutting edge was transformed from micro chipping into tool tipping. This caused by erosion wear .Experimental results indicated that the wear pattern was typical mechanical wear, abrasive wear, cutting edge erosion wear and possible adhesive wear.

In this paper, a strip air-core pulse transformer is designed to convert the current. And, how it works and the process of making iselaborated in detail. The transformer contains leads, insulator, copper strip and supporting core. Under the conditions of the charging voltage 2500 V, 5.52 kA and 1.48 kA peak current of primary and secondary windings are obtained, and correspondingly, the current rising rate is 37 A/s and 138 A/s. It is supported by analysis and experiment that the transformer can reduce the requirement of the rising rate of the switching current effectively. So, the thyristor can be used in the pulse current system which has a high current rising rate and improve its performance on repetition and stability.

SiO2-TiO2 mixed oxides was prepared by the homogeneous precipitation method using tetraethoxysilane and tetrabutyl titanate as precursors. Zinc catalyst supported on SiO2-TiO2 was prepared by the incipient wetness impregnation method and employed as effective catalyst for the direct synthesis of diphenyl carbonate from carbon dioxide and phenol. The stability of the heterogeneous catalyst was also studied in detail. No significant loss of activity was observed during the 5 runs except for the first recycle.

A physical model of magnetron sputtering process was built, the distribution of film thickness on the substrate was deduced, and the data were analysised by using the Mathematica and Matlab. The results show that the distribution of the film thickness on the substrate is uneven and it is also influenced by the radius as well as the distance between the target and substrate. The results of experiment correspond fairly well with the theory. The relational expression provides a theoretical basis for evaluation and estimation of the film thickness.

Based on the fiber bridging model and constant frictional interface stress, this paper derived the P-δ relation for the X-type fiber pulled out of cementitious matrix. By considering the random distributions of the bridging fibers and supposing that rupture of fiber never occurs, it derived the σB-δ relation of a single macro-crack, from which the fracture energy equation was deduced by integral. The derived toughening equations have continuous and explicit forms and are convenient for the approximate estimate of the fracture toughness of the composite. The fracture energy expression suggests that increasing fiber volume fraction, utilizing longer fibers or slender fibers and improving interface bonding are effective methods for improving the composite fracture toughness, while adopting fibers with higher elastic modulus is not a preferred suggestion. It is also found that when using X-type fibers to replace cylindrical fibers with same section area, one can obtain 3~8 times of fracture energy (corresponding leg length-width ratio of the X-type fiber cross section is 5~50).

This paper analyzes the influence of processing surface curvature of the free surface to the cutting width to improve the cutting width of free surface. The results show that this analysis is feasible to improve the process if the machining accuracy allows. It shows that the curvature of the machined surface and the curvature of the cutting tools have a great impact on the cutting width if they are matched reasonable. Therefore, analyzing the curvature of the surface of the surface of free-form surface machining can improve the cutting width effectively.

In order to obtain the aims of weight reduction, efficiency increase and quality assurance of thin-walled parts of aircraft engine, the titanium alloy thin-walled parts are machined by precision machining method in the experiment. In this paper the precision machining method is used to cut titanium alloy thin-walled parts. The data of surface roughness is chosen as constraint conditions, and machining parameters will be optimized. The optimization parameters is feasible in this experiment, the optimization method is helpful to improve machining parameters and machining technology of titanium alloy thin-walled.

Silver nanowires were fabricated in a direct current electric field using a solid-state ionic method, and were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The reverse saturable absorption and optical limiting properties in silver nanowires, suspended in de-ionized water were investigated by using an EKSPLA (PL2143A) picosecond laser, which produced 30 ps laser pulses at 532 nm with a repetition rate of 2 Hz. Experimental results indicate silver nanowires have obvious optical limiting properties.

With the development of aviation and aerospace industry, the performance requirement and part accuracy requirement of aviation engines are increasingly enhanced, and it is difficult to ensure machining accuracy and usage requirement by traditional machining technique. Therefore, the cutting performance and cutting parameter of aviation engine thin-walled parts are researched. Based on FEM (Finite Element Method), simulate cutting of titanium alloy thin-walled parts and analyze the cutting process of a three dimensional model under different cutting parameters so as to obtain the rules of the residual stress and deformation of titanium alloy thin-walled parts. The method referred to in this paper can be used to select the machining parameters of real aero-engine thin-walled, which is helpful to control deformation of workpiece and increase the machining efficiency.

Isotropic pyrolyric graphite (IPG) is a new kind of brittle material, it not only has the general advantages of ordinal carbonaceous materials such as high temperature resistance, lubrication and abrasion resistance, but also has the advantages of impermeability and machinability that carbon/carbon composite doesn’t have. So it can be used for sealing the aeronautics and astronautics engines turbine shaft and the ethylene high-temperature equipment. The mechanism of this material removal during the precision cutting was analyzed by using the theory of strain gradient. The critical cutting thickness of IPG was calculated for the first time. Furthermore, the cutting process parameters such as cutting depth and feed rate which corresponding to the scale of brittle-ductile transition deformation of IPG was calculated. The prediction model of surface roughness in precision cutting of IPG was developed based on the Genetic algorithm. Using the surface roughness prediction model, the study investigates the influence of the cutting speed, the feed rate and the cutting depth on surface roughness in precision turning process was researched.

In order to improve machined surface quality and reduce the deformation, the residual stress involved in cutting titanium alloy was studied under different cutting speed and cutting depth by finite element simulation method. The results indicate that the increase of cutting speed and cutting depth are helpful to the surface residual compressive stress generating. However the increase of cutting speed also leads to the increase of surface residual tensile stress, the effect degree is relatively small. It is required to select higher cutting speed and smaller cutting depth to improve the surface stress state and reduce the unexpected distortion.

The metal-enhanced fluorescence is measured with different thickness of emission film. Silver nanoparticles are immobilized on glass slide by chemical self-assembly method. Rhodamine B molecules are dispersed in the polymer matrix of Poly(methyl methacrylate) (PMMA), then spin coated on prepared silver particles substrate with different thickness from 15 nm to 70 nm. The enhanced fluorescence is observed depending on the thickness of emission film since the average distance between rhodamine B molecules and silver nanoparticles is altered by the PMMA matrix. The 5-fold enhancement is attained. The experiment was explained qualitatively by an integral fluorescence enhancement.

Experiments of tensile mechanical properties of steel 0Cr18Ni9 are done on the MTS 810 tensile testing machine, and the temperature range is from 20°C to 1200°C. The stress vs. strain curves are obtained. Results show that the elastic modulus, yield stress and tensile strength decrease with increasing temperature .Based on the experiment results, the functions of the elastic modulus, yield strength and tensile strength versus temperature are represented by polynomial.

Flame retardant nanocomposites were synthesized by melt-blending phosphorus-containing copolymer (PET-co-DDP) with multi-wall carbon nanotubes. PET-co-DDP was copolymerized with terephthalic acid (TPA), ethylene glycol (EG) and 9, 10-dihydro-10[2, 3-di-(hydroxy carbonyl)propyl]-10-phosphaphenanthrene-10-oxide (DDP). The structure of the nanocomposites was characterized by scan electron microscopy (SEM). Fire property measurements by cone calorimeter revealed that the incorporation of multi wall carbon nanotubes into PET-co-DDP significantly reduced the peak heat release rates compared with the PET-co-DDP. The thermal properties of the nanocomposites were investigated by thermogravimetric analysis (TGA). It was found that the thermal stability of copolyester was improved by the addition of the multi-wall carbon nanotubes. Char formation is the main factor for these improvements. The flame retardant performance was achieved through the formation of a relatively uniform network-structured floccule layer covering the entire sample surface without any cracks or gaps. This layer re-emitted much of the incident radiation back into the gas phase from its hot surface.

A new type of nanocomposite was composited by the way of copolymerization of flame-retardant monomer DDP, PET monomer, terephthalic acid and ethylene dlycol. This article mainly researched the rheology behavior of different slices such as its apparent shear rate and shear stress and the relationship of the both in the use of capillary rheometer, and at the same time, the data of viscous flow activation energy of different sample were obtained. The result shows that under the same temperature, it is the PET/10%DDP/3% BaSO4 that is the best on the mobile performance that needs less shear stress and the temperature control in need is less strict than PFRP.

The principle of surface wave plasma discharge in a rectangular cavity is introduced simply based on surface plasmon polariton theory. The distribution of surface-wave electric field at the interface of the plasma-dielectric slab is investigated by using the three-dimensional finite-difference time-domain method (3D-FDTD) with different slot-antenna structures. And the experimental image of discharge with a novel slot antenna array and the simulation of the electric field with this slot antenna array are both displayed. Combined with the distribution of surface wave excitation and experimental results, the numerical simulation performed by using 3D-FDTD is shown to be a useful tool in the computer-aided antenna design for large area planar-type surface-wave plasma sources.

Microwave-assisted synthesis of poly(L-lactic acid)-poly(ethylene glycol) copolymers(PLEG) by single-step polycondensation of L-lactic acid and poly(ethylene glycol) has been studied. The synthetic conditions, including catalysts, reaction time, pressure and feed weight ratios (mLA/mPEG)on the molecular weights, yields and appearance of the copolymershave been discussed. PLEG copolymers with a weight-average molecular weight of 11000 g/mol can be obtained when L-lactic acid and PEG800 mixture is irradiated for about 60 min under a reduced pressure of around 40 mmHg using SnCl2·2H2O as catalyst. The higher feed weight ratios of mLA/mPEG lead to copolymers with higher molecular weight. The products are characterized by 1H-NMR, GPC and DSC. It is found that the resultant polymers have a relatively narrow polydispersity index (PDI), which is lower than 1.3. The higher glass transition and melting temperatures of the copolymers can be obtained when the content of PEG is lower. Microwave irradiation accelerates...

Gold nanorods with different aspect ratios are prepared in micells using a seeded growth method. Their extinction spectra are observed with an UV–visible spectrophotometer and analysed theoretically. It is known that there are two plasmon resonance peaks for gold nanorod corresponding to transverse and longitudinal plasmon resonance respectively. Moreover, the longitudinal plasmon resonance peak shifts to long wavelength when we increase the aspect ratio determined from TEM. Especially, we model the extinction spectrum using Gans' theory and compare it with our experimental result. Considering the aspect radios distribution of gold nanorods, it is found that longitudinal plasmon resonance peak will be wider than the nanorods with single aspect ratio, which is consistent with our experimental result. In addition, the effect of dielectric constant of surrounding medium is considered.

Double-walled carbon nanotubes could be synthesized by arc-discharge method using ball-milling mixtures of iron, cobalt, nickel and sulfide as catalysts. Structures of these carbon nanotubes were characterized by TEM, HRTEM and Raman spectroscopy. Also the lithium insertion properties were examined. The results showed that the irreversible capacity of the double-walled carbon nanotube lithium ion batteries is high, which is considered to be related to the formation of SEI on the surface of the electrodes in the process of electrochemistry reaction.

Single-walled carbon nanotubes can be used as electron sources in the process of field emission, and have great potential for practical application of the field emission display (FED) panels with large screen size. We fabricated a FED using the single-walled carbon nanotubes (SWNTs) as the cathode by the screen-printing process. Test showed that the SWNTs emitters exhibit excellent macroscopic emission properties. It has low turn-on voltage (2.7 V/μm) and high brightness, with a high current density of good uniformity and stability. It was observed that the field emission qualitatively follows the conventional Fowler–Nordheim (F–N) theory, and aging treatment played an important role in improving the image uniformity and stability. Compared to other complicated processes, the simple fabrication using screen-printing process seems to be advantageous for practical application.

According to the size effect theory established on the concept of geometrically necessary dislocations and results of nano-indentation experiments, a novel brittle-ductile mechanism of ultra-precision turning of single crystal silicon is proposed. The accurate critical chip thickness is firstly calculated on the basis of theoritical analysis. A macro-micro cutting model is created based on the brittle-ductile transition mechanism. Finally, the results of study are testified through experiments.