THE COUPLED EFFECTS OF MECHANICAL DEFORMATION AND ELECTRONIC PROPERTIES IN CARBON NANOTUBES

Coupled effects of mechanical and electronic behavior in single walled carbon nanotubes are investigated by using quantum mechanics and quantum molecular dynamics.It is found that external applied electric fields can cause charge polarization and significant geometric deformation in metallic and semi-metallic carbon nanotubes.The electric induced axial tension ratio can be up to 10% in the armchair tube and 8.5% in the zigzag tube.Pure external applied load has little effect on charge distribution,but indeed influences the energy gap.Tensile load leads to a narrower energy gap and compressive load increases the gap.When the CNT is tensioned under an external electric field,the effect of mechanical load on the electronic structures of the CNT becomes significant,and the applied electric field may reduce the critical mechanical tension load remarkably.Size effects are also discussed.

Coupled thermo-hydro-mechanical process in buffer material and self-healing effects with joints

Within the multi-barrier system for high-level waste disposal,the technological gap formed by combined buffer material block becomes the weak part of buffer layer.In this paper,Gaomiaozi bentonite buffer material with technological gap was studied,the heat transfer induced by liquid water flow and water vapor was embedded into the energy conservation equation.Based on the Barcelona basic model,the coupled thermo-hydro-mechanical model of unsaturated bentonite was established by analyzing the swelling process of bentonite block and the compression process of joint material.The China-Mock-up test was adopted to compare the numerical calculation results with the test results so as to verify the rationality of the proposed model.On this basis,the effect of joint self-healing on dry density,thermal conductivity and permeability coefficient of buffer material was further analyzed.The results show that,with bentonite hydrating and swelling,the joint material gradually increases in dry density,and exhibits comparatively uniform hydraulic and thermal conductivity properties as compacted bentonite block.As a result,the buffer material gradually shifts to homogenization due to the coordinated deformation.

Conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled plasmas

A numerical model is developed to study the conductivity effects during the transition from collisionless to collisional regimes in cylindrical inductively coupled argon plasmas at pressures of 0.1-20 Pa.The model consists of electron kinetics module,electromagnetics module,and global model module.It allows for self-consistent description of non-local electron kinetics and collisionless electron heating in terms of the conductivity of homogeneous hot plasma.Simulation results for non-local conductivity case are compared with predictions for the assumption of local conductivity case.Electron densities and effective electron temperatures under non-local and local conductivities show obvious differences at relatively low pressures.As increasing pressure,the results under the two cases of conductivities tend to converge,which indicates the transition from collisionless to collisional regimes.At relatively low pressures the local negative power absorption is predicted by non-local conductivity case but not captured by local conductivity case.The two-dimensional(2D)profiles of electron current density and electric field are coincident for local conductivity case in the pressure range of interest,but it roughly holds true for non-local conductivity case at very high pressure.In addition,an effective conductivity with consideration of non-collisional stochastic heating effect is introduced.The effective conductivity almost reproduces the electron density and effective electron temperature for the non-local conductivity case,but does not capture the non-local relation between electron current and electric field as well as the local negative power absorption that is observed for nonlocal conductivity case at low pressures.

The effects of process conditions on the plasma characteristic in radio-frequency capacitively coupled SiH_4/NH_3/N_2 plasmas: Two-dimensional simulations

A two-dimensional （2D） fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma （CCP） reactor. The plasma–wall interaction （including the deposition） is modeled by using surface reaction coefficients. In the present paper we try to identify, by numerical simulations, the effect of variations of the process parameters on the plasma properties. It is found from our simulations that by increasing the gas pressure and the discharge gap, the electron density profile shape changes continuously from an edge-high to a center-high, thus the thin films become more uniform. Moreover, as the N2 /NH3 ratio increases from 6/13 to 10/9, the hydrogen content can be significantly decreased, without decreasing the electron density significantly.

<i>In Situ</i>Analysis of Copper Alloys by Femtosecond Laser Ablation Inductively Coupled Plasma Mass Spectrometry: Constrains on Matrix Effects

Direct analysis of copper-base alloys using laser ablation techniques is an increasingly common procedure in cultural heritage studies. However, main discussions remain focused on the possibility of using non-matrix matched external reference materials. To evaluate the occurrence of matrix effects during in situ microanalysis of copper-base materials, using near infrared femtosecond laser ablation techniques (NIR fs-LA-ICP-MS), two bronzes, i.e., (Sn-Zn)-ternary and (Sn)-binary copper-matrix reference materials, as well as a reference synthetic glass (NIST-SRM-610) have been analyzed. The results have been compared to data obtained on a sulfide-matrix reference material. Similar values in relative sensitivity averages of 63Cu, 118Sn and 66Zn, as well as in 118Sn/63Cu and 66Zn/63Cu ratios were obtained, for all analyzed matrix types, i.e., copper-base-, silicate-, and sulfide-reference materials. Consequently, it is possible to determinate major and minor element concentrations in copper alloys, i.e., Cu, Sn and Zn, using silicate and sulfide reference materials as external calibrators, without any matrix effect and over a wide range of concentrations (from wt.% to ppm). Equally, Cu, Sn and Zn concentrations can be precisely determined in sulfides using homogeneous alloys (reference) materials as an external calibrator. Thus, it is possible to determine Cu, Sn and Zn in copper-base materials and their ore minerals, mostly sulfides, in a single analytical session, without requiring specific external calibrators for each matrix type. In contrast, immiscible elements in copper matrix, such as Pb and Fe show notable differences in their relative sensitivity values and ratios for different matrix-materials analyzed, implying that matrix-matched external calibrations remain to be applied for their trace quantification.

Evaluation of Protective Effects of Bioactive Phytochemicals Against Methotrexate in Salmonella typhimurium TA1535/pSK1002 Coupled with Micronucleus Assay

We evaluated the antimutagenic effects kinds of bioactive phytochemicals and of 10 some phytochemical combinations against methotrexate （MTX）-induced genotoxicity by the umu test in Salmonella typhimurium TA1535/rpSK1002 combined with a micronucleus assay. We observed that allicin, proanthocyanidins, polyphenols, eleutherosides, and isoflavones had higher antimutagenic activities than the other five types of bioactive phytochemicals. At the highest dose tested, MTX-induced genotoxicity was inhibited by 25%-75%. Kunming mice treated by MTX along with bioactive phytochemical combinations showed significant reduction in micronucleus induction and sperm abnormality rate （P〈0.01）. These results indicate that bioactive phytochemical combinations can be potentially used as new cytoprotectors.

A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics

A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation.

Crust-Mantle Structure and Coupling Effects on Mineralization : An Example from Jiaodong Gold Ore Deposits Concentrating Area, China

Based on the results of two dimension velo city structure, 1∶100 000 aeromagnetic anomaly, 1∶200 000 bouguer gravity anom aly and seismic anisotropy of Jiaodong and neighboring region in Shandong, China , the information of geophysical field was divided into two parts: deep and sh allow focus fields. And then, the information of two different fields was c ombined with that of deep seated geology and ore deposit features. The syntheti c result was adopted to analyze three dimension structure, to probe into crust mantle coupling effects of mineralization and dynamics of ore formation system .

NUMERICAL STUDIES ON RESONANT AND ENHANCEMENT EFFECTS FOR COUPLING OF MICROWAVE PULSES INTO NARROW SLOTS

In this paper, modifications to the finite-difference time-domain(FD-TD) method for modeling microwave pulse coupling into a slot, which is much narrower than one conventional FD-TD cell, are discussed. The coupling process of microwave pulse into a slot is studied by using the modified FD-TD method, and the dependence of microwave coupling on slot sizes, the carrier frequencies and the polarization directions of the incident waves is analysed. Resonant and enhancement effects which occur in this process are observed. The condition at which the resonant effect takes place is also presented.

Coupling Effects of Irrigation and Phosphorus Fertilizer Applications on Phosphorus Uptake and Use Efficiency of Winter Wheat

The water content and nutrient in soil are two main determine factors to crop yield and quality, managements of which in field are of great importance to maintain sustainable high yield. The objective of this study was to measure the uptake, forms, and use efficiency of phosphorus （P） in wheat under four levels of irrigation （W0, W1, W2, and W3） and three levels of P application （P0, P1, and P2） through two growth seasons of wheat （2008-2010）. The field experiment was carried out in a low level of soil P concentration and the eultivar was Jimai 20. The results indicated that P fertilizer combined with irrigation not only improved the activity of phosphatase in soil, but also increased P accumulation in wheat, similar results was found in the grain of wheat, the content of total P increased significantly. Meanwhile, the mainly existence forms of P in grain were the lecithoid-P and labile organic-P. On the other hand, in comparison to the irrigation, the dry matter and grain P production efficiency and postponing P application of wheat increased with increasing Papplication rates within the range of 0-180 kg P2O5 ha-1. The interaction between P and irrigation also significantly （P〈0.01） affected on the P accumulation, grain total P, grain phospholipid P, and P production efficiency. In this study, therefore, the P applications and irrigation improved grain P production efficiency and postponing P application of winter wheat, and W2P2 treatment （180 kg P2O5 ha-1 combination with 120 mm irrigation） had a high P accumulation and P use efficiency, it was an optimum level for P fertilizer application and irrigation in this region.

Coupling Effects of A Deep-Water Drilling Riser and the Platform and the Discharging Fluid Column in An Emergency Disconnect Scenario

As drilling operations move into remote locations and extreme water depths, recoil analysis requires more careful considerations and the incidence of emergency disconnect is increased inevitably. To accurately capture the recoil dynamics of a deep-water riser in an emergency disconnect scenario, researchers typically focus on modelling the influential subsystems (e.g., the tensioner, the mud discharge and seawater refilling process) which can be solved in the preprocessing, and then the determined parameters are transmitted into an existing global riser analysis software. Distinctively, the current study devotes efforts into the coupling effects resulting from that the suspended riser reacts the platform heave motion via the tensioner system in the course of recoil and the discharging fluid column follows the oscillation of the riser in the mud discharge process. Four simulation models are established based on lumped mass method employing different formulas for the top boundary condition of the riser and the discharging flow acceleration. It demonstrates that the coupling effects discussed above can significantly affect the recoil behavior during the transition phase from initial disconnect to the final hang-off state. It is recommended to develop a fully- coupled integrated model for recoil analysis and anti-recoil control system design before extreme deep-water applications.

Study on Rigid-Flexible Coupling Effects of Floating Offshore Wind Turbines

In order to account for rigid-flexible coupling effects of floating offshore wind turbines, a nonlinear rigid-flexible coupled dynamic model is proposed in this paper. The proposed nonlinear coupled model takes the higher-order axial displacements into account, which are usually neglected in the conventional linear dynamic model. Subsequently,investigations on the dynamic differences between the proposed nonlinear dynamic model and the linear one are conducted. The results demonstrate that the stiffness of the turbine blades in the proposed nonlinear dynamic model increases with larger overall motions but that in the linear dynamic model declines with larger overall motions.Deformation of the blades in the nonlinear dynamic model is more reasonable than that in the linear model as well.Additionally, more distinct coupling effects are observed in the proposed nonlinear model than those in the linear model. Finally, it shows that the aerodynamic loads, the structural loads and global dynamic responses of floating offshore wind turbines using the nonlinear dynamic model are slightly smaller than those using the linear dynamic model. In summary, compared with the conventional linear dynamic model, the proposed nonlinear coupling dynamic model is a higher-order dynamic model in consideration of the rigid-flexible coupling effects of floating offshore wind turbines, and accord more perfectly with the engineering facts.

Comparative study of aeroacoustic performance of 1/8 and 1/1 pantographs coupled with cavity

The technology of pantograph sinking in the cavity is generally adopted in the new generation of high-speed trains in China for aerodynamic noise reduction in this region. This study takes a high-speed train with a 4-car formation and a pantograph as the research object and compares the aerodynamic acoustic performance of two scale models, 1/8 and 1/1, using large eddy simulation and Ffowcs Williams–Hawkings integral equation. It is found that there is no direct scale similarity between their aeroacoustic performance. The 1/1 model airflow is separated at the leading edge of the panhead and reattached to the panhead, and its vortex shedding Strouhal number(St) is 0.17. However, the 1/8 model airflow is separated directly at the leading edge of the panhead, and its St is 0.13. The cavity's vortex shedding frequency is in agreement with that calculated by the Rooster empirical formula. The two scale models exhibit some similar characteristics in distribution of sound source energy, but the energy distribution of the 1/8 model is more concentrated in the middle and lower regions. The contribution rates of their middle and lower regions to the radiated noise in the two models are 27.3% and 87.2%, respectively. The peak frequencies of the radiated noise from the 1/1 model are 307 and 571 Hz. The 307 Hz is consistent with the frequency of panhead vortex shedding, and the 571 Hz is more likely to be the result of the superposition of various components. In contrast, the peak frequencies of the radiated noise from the 1/8 scale model are 280 and 1970 Hz. The 280 Hz comes from the shear layer oscillation between the cavity and the bottom frame, and the 1970 Hz is close to the frequency at which the panhead vortex sheds. This shows that the scaled model results need to be corrected before applying to the full-scale model.

Finite size effects on helical edge states in HgTe quantum wells with the spin orbit coupling due to bulk- and structure-inversion asymmetries

There is a quantum spin Hall state in the inverted HgTe quantum well, characterized by the topologically protected gapless helical edge states lying within the bulk gap. It has been found that for a strip of finite width, the edge states on the two sides can couple together to produce a gap in the spectrum. The phenomenon is called the finite size effect in quantum spin Hall systems. In this paper, we investigate the effects of the spin-orbit coupling due to bulk- and structure-inversion asymmetries on the finite size effect in the HgTe quantum well by means of the numerical diagonalization method. When the bulk-inversion asymmetry is taken into account, it is shown that the energy gap Eg of the edge states due to the finite size effect features an oscillating exponential decay as a function of the strip width of the HgTe quantum well. The origin of this oscillatory pattern on the exponential decay is explained. Furthermore, if the bulk- and structure-inversion asymmetries are considered simultaneously, the structure-inversion asymmetry will induce a shift of the energy gap Eg closing point. Finally, based on the roles of the bulk- and structure-inversion asymmetries on the finite size effects, a way to realize the quantum spin Hall field effect transistor is proposed.

Effects of the coupling process on shortwave radiative feedback during ENSO in FGOALS-g

Satisfactory simulation of negative shortwave（SW） radiative feedback during ENSO in the equatorial Pacific remains a challenging issue for climate models. Previous studies have focused on specific physical processes in the atmospheric and/or oceanic model, but the coupling process in coupled models has not received much attention. To investigate the coupling effect on SW feedback, two versions of an AGCM and their corresponding coupled models are analyzed. Results indicate that the effects of the coupling process in the two versions lead to weakening and enhancement of the negative feedback in the earlier and new versions, respectively, mainly due to their different changes in cloud fraction feedback and dynamical feedback. Further examination of the nonlinearity of the feedback reveals that the opposite coupling effects in the two versions originate from their different responses to El Nio and to La Nia.

Dynamic Characteristics of Long -Span Steel -Concrete CompositeBeam Bridge Based on Vehicle -Bridge Coupling Effect

In order to investigate the effect of vehicle-bridge coupling on the dynamic characteristics of the bridge,a steel-concrete composite beam suspension bridge is taken as the research object,and a three-dimensional spatial model of the bridge and a biaxial vehicle model of the vehicle are established,and then a vehicle-bridge coupling vibration system is constructed on the basis of the Nemak-βmethod,and the impact coefficients of each part of the bridge are obtained under different bridge deck unevenness and vehicle speed.The simulation results show that the bridge deck unevenness has the greatest influence on the vibration response of the bridge,and the bridge impact coefficient increases along with the increase in the level of bridge deck unevenness,and the impact coefficient of the main longitudinal girder and the secondary longitudinal girder achieves the maximum value when the level 4 unevenness is 0.328 and 0.314,respectively;when the vehicle speed is increased,the vibration response of the bridge increases and then decreases,and the impact coefficient of the bridge in the middle of the bridge at a speed of 60 km/h achieves the maximum value of 0.192.

Interfacial coupling effects in g-C_(3)N_(4)/In_(x)Sb_(2-x)S_(3) heterojunction for enhanced photocatalytic activity under visible light

A series of In_(x)Sb_(2-x)S_(3) nanosheets modified g-C_(3)N_(4)(In_(x)Sb_(2-x)S_(3)-TCN)heterojunctions with different g-C_(3)N_(4) contents were fabricated by an in situ deposition method.All the In_(x)Sb_(2-x)S_(3)-TCN composites were applied as photocatalysts in Cr(Ⅵ)polluted water treatment and the results displayed that In_(x)Sb_(2-x)S_(3)-TCN could effectively remove Cr(Ⅵ)under visible light through synergistic effects of adsorption and photocatalytic reduction.Especially,In_(x)Sb_(2-x)S_(3)-TCN-70(70 mg g-C_(3)N_(4)) exhibited the most excellent adsorption and photocatalytic reduction performance among all composites,which possessed a high equilibrium adsorption capacity of 12.45 mg/g in a 30.0 mg/L Cr(Ⅵ)aqueous solution,and reduced Cr(Ⅵ)to Cr(Ⅲ)within 10 min under visible light irradiation.DRS and PL results indicated that the interfacial coupling effect between g-C_(3)N_(4)and In_(x)Sb_(2-x)S_(3) enhanced the utilization efficiency of visible light and suppressed photoinduced carrier recombination,which improved the photocatalytic activity of composites.Moreover,the photocatalyst exhibited satisfactory reduction activity and good stability after 5 cycles of Cr(Ⅵ)adsorptionphotoreduction.

Coupled hydro-mechanical effect of a fractured rock mass under high water pressure

To explore the variation of permeability and deformation behaviors of a fractured rock mass in high water pressure,a high pressure permeability test（HPPT）,including measuring sensors of pore water pressure and displacement of the rock mass,was designed according to the hydrogeological condition of Heimifeng pumped storage power station.With the assumption of radial water flow pattern in the rock mass during the HPPT,a theoretical formula was presented to estimate the coefficient of permeability of the rock mass using water pressures in injection and measuring boreholes.The variation in permeability of the rock mass with the injected water pressure was studied according to the suggested formula.By fitting the relationship between the coefficient of permeability and the injected water pressure,a mathematical expression was obtained and used in the numerical simulations.For a better understanding of the relationship between the pore water pressure and the displacement of the rock mass,a 3D numerical method based on a coupled hydro-mechanical theory was employed to simulate the response of the rock mass during the test.By comparison of the calculated and measured data of pore water pressure and displacement,the deformation behaviors of the rock mass were analyzed.It is shown that the variation of displacement in the fractured rock mass is caused by water flow passing through it under high water pressure,and the rock deformation during the test could be calculated by using the coupled hydro-mechanical model.

Natural convection flow of a couple stress fluid between two vertical parallel plates with Hall and ion-slip effects

The Hall and ion-slip effects on fully developed electrically conducting couple stress fluid flow between vertical parallel plates in the presence of a temperature dependent heat source are investigated. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using the homotopy analysis method （HAM）. The effects of the magnetic parameter, Hall parameter, ion-slip parameter and couple stress fluid parameter on velocity and temperature are discussed and shown graphically

Nonlocal effect on resonant radiation force exerted on semiconductor coupled quantum well nanostructures

Based on the microscopic nonlocal optical response theory, the resonant radiation force exerted on a semiconductorcoupled quantum well nanostructure(CQWN), induced by the nonlocal interaction between lasers and electrons in conduction bands, is investigated for two different polarized states. The numerical results show that the spatial nonlocality of optical response can cause a radiation shift(blue-shift) for the spectrum of the resonant radiation force, which is dependent on the CQWN width ratio, the barrier height, and polarized states sensitively. It is also confirmed that the resonant radiation force is steerable by the incident and polarized directions of incident light. This work may provide an advantageous method for detecting internal quantum properties of nanostructures, and open novel and raising possibilities for optical manipulation of nano-objects using laser-induced radiation force.