Oxide Thickness Effects on n-MOSFETs Under On-State Hot-Carrier Stress

Hot carrier induced (HCI) degradation of surface channel n MOSFETs with different oxide thicknesses is investigated under maximum substrate current condition.Results show that the key parameters m and n of Hu's lifetime prediction model have a close relationship with oxide thickness.Furthermore,a linear relationship is found between m and n .Based on this result,the lifetime prediction model can be expended to the device with thinner oxides.

MECHANISM ANALYSIS OF THICKNESS EFFECT ON MIXED MODE Ⅰ/Ⅱ FRACTURE OF LC4-CS ALUMINUM ALLOY

Mixed mode Ⅰ/Ⅱ fracture erperiments of LC4-CS aluminum alloy were conductedby using tension--shear specimens with thicknesses of 2, 4, 8 and 14mm. Fracturemechanisms of thickness effect on mixed mode Ⅰ/Ⅱ fracture were first examined fromfracture surface morphology to correlate with the macroscopic fracture behavior andstress state. It is found that specimen thickness has a strong influence on mixed modefracture. As thickness varies from thin to thick the macroscopic fracture surfacesappear the characteristics of plane stress state (2mm, 4mm--thick specimen), three--dimensional stress state (8mm--thick specimens), and plane strain state (14mm--thickspecimens), respectively. The specimens of all kinds of thicknesses are typical of ten-sile type failure under mode Ⅰ loading condition and shear type failure under mode Ⅱloading condition. Two distinct features coexist on the fracture surfaces under mixedmode loading conditions, and the corresponding proportion varies with loading mix-ity. Void--growth processes are the failure mechanism in both predominately tensile-and shears--type fractures. The size and depth of dimples on the fracture surface varygreatly with thickness. Therefore, it is extraordinary necessary to take into accountthe thickness effect when a mixed mode fracture criterion is being established.

Caving thickness effects of surrounding rocks macro stress shell evolving characteristics

In order to explore the influence of different caving thicknesses on the MSS distributionand evolving characteristics of surrounding rocks in unsymmetrical disposal andfully mechanized top-coal caving (FMTC),based on unsymmetrical disposal characteristics,the analyses of numerical simulation,material simulation and in-situ observation weresynthetically applied according to the geological and technical conditions of the 1151(3)working face in Xieqiao Mine.The results show that the stress peak value of the MSS-baseand the ratio of MSS-body height to caving thickness are nonlinear and inverselyproportional to the caving thickness.The MSS-base width,the MSS-body height,theMSS-base distance to working face wall and the rise distance of MSS-base beside coalpillar are nonlinear and directly proportional to the caving thickness.The characteristics ofMSS distribution and its evolving rules of surrounding rocks and the integrated cavingthickness effects are obtained.The investigations will provide lots of theoretic referencesto the surrounding rocks' stability control of the working face and roadway,roadway layout,gas extraction and exploitation,and efficiency of caving,etc.

Thickness effect on microstructural and mechanical properties of pulse-laser treated Ti/Ni multilayer thin films

Previous work showed that pulse-laser irradiation can strengthen metal multilayer thin films through intermetallic formation and the degree of strengthening is a function of laser pulse energy.In this work,the effect of individual layer thickness(λ)and total multilayer thickness(h)on the resulting microstructure and mechanical strength of laser-treated Ti/Ni multilayers was further investigated.Experiments were carried out on fourλ/hcombinations using individual layer thickness of 20 nm and 50 nm,and total multilayer thickness of 500 nm and1μm,respectively.Obvious intermetallic strengthening was observed in the 500 nm thick multilayers,especially with the 20 nm layer thickness,but not in the 1μm thick multilayers.Further,the multilayer surface morphology after laser treatment was observed to be dominated by competition between laser-induced optical interference and thermal melting,with the former leading to ripple or cross-hatched patterns and the latter leading to melted surfaces with pores and cracks.

Eigen value analysis of composite hollow shafts using modified EMBT formulation considering the shear deformation along the thickness direction

Composite hollow shafts are used in power transmission applications due to their high specific stiffness and high specific strength.The dynamic characteristics of these shafts are important for transmission applications.Dynamic modelling of these shafts is generally carried out using Equivalent Modulus Beam Theory(EMBT)and Layerwise Beam Theory(LBT)formulations.The EMBT formulation is modified by considering stacking sequence,shear normal coupling,bending twisting coupling and bending stretching coupling.It is observed that modified EMBT formulation is underestimating the shafts stiffness at lower length/mean diameter(l/dm)ratios.In the present work,a new formulation is developed by adding shear deformation along the thickness direction to the existing modified EMBT formulation.The variation of shear deformation along the thickness direction is found using different shear deformation theories,i.e.,first-order shear deformation theory(FSDBT),parabolic shear deformation theory(PSDBT),trigonometric shear deformation theory(TSDBT),and hyperbolic shear deformation theory(HSDBT).The analysis is performed at l/d_(m) ratios of 5,10,15,20,25,30,35,and 40 for carbon/epoxy composites,E-glass/epoxy composites,and boron/epoxy composite shafts.The results show that new formulation has improved the bending natural frequency of the composite shafts for l/d_(m)<15 in comparison with modified EMBT.The effect of new formulation is more significant for the second and third bending modes of natural frequencies.

Size dependent free vibration analysis of functionally graded piezoelectric micro/nano shell based on modified couple stress theory with considering thickness stretching effect

Higher-order shear and normal deformation theory is used in this paper to account thickness stretching effect for free vibration analysis of the cylindrical micro/nano shell subjected to an applied voltage and uniform temperature rising.Size dependency is included in governing equations based on the modified couple stress theory.Hamilton’s principle is used to derive governing equations of the cylindrical micro/nano shell.Solution procedure is developed using Navier technique for simply-supported boundary conditions.The numerical results are presented to investigate the effect of significant parameters such as some dimensionless geometric parameters,material properties,applied voltages and temperature rising on the free vibration responses.

Effective elastic thickness of the lithosphere from joint inversion in western China and its implications

The western China lies in the convergence zone between Eurasian and Indian plates.It is an ideal place to study the lithosphere dynamics and tectonic evolutions on the continental Earth.The lithospheric strength is a key factor in controlling the lithosphere dynamics and deformations.The effective elastic thickness(T_(e))of the lithosphere can be used to address the lithospheric strength.Previous researchers only used one of the admittance or coherence methods to investigate the T_(e) in the western China.Moreover,most of them ignored the internal loads of the lithosphere during the T_(e) calculation,which can produce large biases in the T_(e) estimations.To provide more reliable T_(e) estimations,we used a new joint inversion method that integrated both admittance and coherence techniques to compute the T_(e) in this study,with the WGM2012 gravity data,the ETOPO1 topographic data,and the Moho depths from the CRUST1.0 model.The internal loads are considered and investigated using the load ratio(F).Our results show that the joint inversion method can yield reliable T_(e) and F values.Based on the analysis of T_(e) and F distributions,we suggest(1)the northern Tibetan Plateau could be the front edge of the plate collision of Eurasian and Indian plates;(2)the southern and part of central Tibetan Plateau have a strong lithospheric mantle related to the rigid underthrusting Indian plate;(3)the southeastern Tibetan Plateau may be experiencing the delamination of lithosphere and upwelling of asthenosphere.

Effects of Thickness and Temperature on Thermoelectric Properties of Bi2Te3-Based Thin Films

Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices of different thicknesses are prepared on the silicon dioxide substrates by magnetron sputtering technique and thermally annealed at 573 K for 30 min. Thermoelectric（TE）measurements indicate that optimal thickness and thickness ratio improve the TE performance of Bi_2Te_3 thin films and GeTe/B_2Te_3 superlattices, respectively. High TE performances with figure-of-merit（ZT） values as high as 1.32 and 1.56 are achieved at 443 K for 30 nm and 50 nm Bi_2Te_3 thin films, respectively. These ZT values are higher than those of p-type Bi_2Te_3 alloys as reported. Relatively high ZT of the GeTe/B_2Te_3 superlattices at 300-380 K were 0.62-0.76. The achieved high ZT value may be attributed to the unique nano-and microstructures of the films,which increase phonon scattering and reduce thermal conductivity. The results indicate that Bi_2Te_3-based thin films can serve as high-performance materials for applications in TE devices.

Analysis of the Impact Resistance of Photovoltaic Panels Based on the Effective Thickness Method

Based on the recent development of renewable energy utilization technology,in addition to centralized photovol-taic power plants,distributed photovoltaic power generation systems represented by building-integrated photo-voltaic systems are frequently employed for power supply.Therefore,in the architectural design,the double-glass photovoltaic module used in the integrated photovoltaic building system puts forward a higher load-bearing capa-city requirement and the corresponding simplified method of carrying capacity check.This article focuses on the simplified method of checking the bearing capacity of the four-sided simply supported double-glass photovoltaic module.First,the principle of equivalent stiffness is used to calculate the effective thickness.Then,the rationality of this approach is verified by comparing the bending states of sandwich panels under different shear moduli.The double-glass photovoltaic module is equivalent to a single-layer board,and its effectiveness is verified by compar-ing the impact test results of the double-glass photovoltaic module with the results of the single-layer board.But the comparison with the test results shows that,from the perspective of architectural design,the effective thick-ness results in this paper can ensure that the building structure has sufficient bearing capacity,but the four-side simply supported boundary theory cannot fully reflect the calculation of the bearing capacity of the four-side clamped double-glass photovoltaic module.

Novel attributes and design considerations of effective oxide thickness in nano DG MOSFETs

Impacts of effective oxide thickness on a symmetric double-gate MOSFET with 9-nm gate length are studied, using full quantum simulation. The simulations are based on a self-consistent solution of the two-dimensional （2D） Poisson equation and the Schr6dinger equation within the non-equilibrium Green＇s function formalism. Oxide thickness and gate dielectric are investigated in terms of drain current, on-off current ratio, off current, sub-threshold swing, drain induced barrier lowering, transconductance, drain conductance, and voltage. Simulation results illustrate that we can improve the device performance by proper selection of the effective oxide thickness.

Effective Elastic Thickness of the Lithosphere in the Mariana Subduction Zone and Surrounding Regions and Its Implications for Their Tectonics

To understand the rheology,structure,and tectonics of the lithosphere in the Mariana subduction zone and surrounding regions,we calculated the effective elastic thickness of the lithosphere(Te)in these areas using the improved moving window admittance technique(MWAT)method.We find that smaller data grid spacing can better reflect Te variations in the subduction zone.The Te of the study region ranges from 0 to 47 km.The Te is reduced from 40 km on the seaward side of the outer-rise region to 1-2 km along the trench axis.The lithospheric breaking distance from the trench axis ranges from 0 to 250 km.We suggest that the intermediate Te values in seamounts and high Te values on the seaward side of the outer-rise region respectively reflect the‘fossil’rheological state and current lithospheric strength of the Pacific plate.The faulting induced by the downward bending of subducting plate not only ruptures the lithosphere but also contributes to the mantle serpentinization,significantly reducing the lithospheric strength.The largest breaking distance of the Ogasawara Plateau may be due to the increase in the mass load of the subducting plate in the Ogasawara Plateau and the significant horizontal bending force in the plate caused by the resistance of seamounts to subduction.Furthermore,a good positive correlation exists between the breaking distance and subduction dip angle along the trench axis.We suggest that the subducting plate with a larger breaking distance is likely to form a larger subduction angle.

Effective Elastic Thickness of Southeast Part ofArctic Ocean-Eurasia Continent-PacificOcean Geoscience Transect

The effective lithospheric elastic thickness of the continent is an important parameter for examination of the large-scale structure and analyses of the mechanism of isostatic compensation within the plate, and a parameter standing for the strength of the lithosphere. The Te values along Quanzhou-Heishui, the southeast section of the Arctic Ocean-Eurasian Continent-Pacific Ocean geoscience transect, are estimated by using the coherence technique developed by Forsyth. Studies of the feature of the coherence between gravity and topography suggest that at short wavelengths (6. 6-100 km) for each data box that is used to estimate Te, the plate is strong enough to support topographic loads and gravity and topography are uncorrelated. At long wavelengths where the plate is deflected by surface and subsurface loads are compensated by the flexure model. Sichuan land-stone with low heat-flow values has high Te values whereas in Ninghua, Datian, land-stone with high heat-flow values has low Te values, which reflects a correlation, low heat-flow values corresponding to high Te values and high heat-flow values corresponding to low Te values. Te values can be divided into two sections: northwest high section and southeast low section. There is roughly a positive correlation between crustal thickness and effective elastic thickness of the lithosphere.

Effects of MgO Thickness and Roughness on Perpendicular Magnetic Anisotropy in MgO/CoFeB/Ta Multilayers

The dependence of perpendicular magnetic anisotropy （PMA） on the barrier layer MgO thickness in MgO/CoFeB /Ta multilayers is investigated. The results show that the strongest PMA occurs in a small window of about 2 4nm with the increase of MgO thickness from 1-1Onto. The crystalline degree of MgO and the change of interatomic distance along the out-of-plane direction may be the main reasons for the change of PMA in these multilayers. Moreover, the roughnesses of 2- and 4-nm-thick MgO samples are 3.163 and 1.8 nm, respectively, and both the samples show PMA. These results could be used to tune the magnetic characteristic of the ultra thin CoFeB film for future applications in perpendicular magnetic devices.

Effects of Film Thickness and Ar/O2 Ratio on Resistive Switching Characteristics of HfOx-Based Resistive-Switching Random Access Memories

Cu/HfOx/n^＋Si devices are fabricated to investigate the influence of technological parameters including film thickness and Ar/02 ratio on the resistive switching （RS） characteristics of HfOx films, in terms of switch ratio, endurance properties, retention time and multilevel storage. It is revealed that the RS characteristics show strong dependence on technological parameters mainly by altering the defects （oxygen vacancies） in the film. The sample with thickness of 2Onto and Ar/O2 ratio of 12：3 exhibits the best RS behavior with the potential of multilevel storage. The conduction mechanism of all the films is interpreted based on the filamentary model.

Thickness-dependent structural stability and transition in molybdenum disulfide under hydrostatic pressure

Understanding the physical mechanism of structural stability and transition in various polytypes of layered transition metal dichalcogenides under the external stimulus is of crucial importance for their new applications.Here,we investigate the thickness-dependent structural properties of MoS2 under the condition of hydrostatic pressure in terms of bond relaxation and thermodynamics considerations.For both types of MoS2 structures,we find that the transition and metallization are significantly modulated by hydrostatic pressure and the number of layers.We establish a pressure-size phase diagram to address the transition mechanism.Our study not only provides insights into the thickness-dependent structural properties of MoS2,but also shows a theoretical guidance for the design and fabrication of MoS2-based devices.

Lithospheric strength of the Anatolian plateau and implications for strong earthquake activity in Turkey

On February 6, 2023, the doublet earthquake including two main shocks with magnitudes M_(W)7.8 and M_(W)7.5, occurred near the western side of the East Anatolian Fault at the southeast boundary of the Anatolian Plateau in Turkey. Based on the WGM2012 Bouguer gravity anomaly data and the Etopo1topography data, this study first introduced a joint inversion of admittance and coherence functions and used the Bayesian optimal parameter estimation method to obtain the effective elastic thickness Teand loading ratio F of the lithosphere for various tectonic units in the Anatolian Plateau. Secondly, we discussed the characteristics and influencing factors of the lithospheric mechanical strength and analyzed its relationship with seismic activity. The lithospheric mechanical strength of the Anatolian Plateau showed clear lateral heterogeneity and a "weak-strong-weak" spatial pattern from east to west,reflecting various tectonic processes. At last, the strong seismic activity was found where the lithospheric strength was low in the Anatolian Plate. We also incorporated GPS strain rate and other results to investigate the tectonic background and primary causes of the M_(W)7.8 and M_(W)7.5 doublet earthquakes in Turkey. The results have a good insight into urban safety design in the Turkish region, including postdisaster rehabilitation, earthquake hazard assessment, and loss reduction.

Three-Dimensional Stress Fields in Finite Thickness Plate with Hole Under Shear Load

The theoretical solutions are obtained for the three-dimensional(3-D)stress field in an infinite isotropic elastic plate with a through-the-thickness circular hole subjected to shear load at far field by using Kane and Mindlin′s assumption based on the stress function method.Based on the present solutions,the characteristics of 3-D stress field are analyzed and the emphasis is placed on the effects of the plate thickness and Poisson′s ratio on the deviation of the present 3-D in-plane stress from the related plane stress solutions,the stress concentration and the out-of-plane constraint.The present solutions show that the stress concentration factor reaches its peak value of about 8.9% which is higher than that of the plane stress solutions.As expected,the out-of-plane stress constraint factor can reach 1on the surface of the hole when the plate is a very thick one.

Effects of Specimen Shape and Size on Water Loss and Drying Shrinkage of Cement-based Materials

The effects of specimen size and shape on development of water loss and shrinkage of mortar and concrete respectively were investigated. The experimental results showed that the effects of specimen size and shape on water loss ratio were consistent with those on drying shrinkage strain. It is also indicated that drying shrinkage strain has obvious linear correlation with water loss ratios independent of specimen size and shape. The effects of specimen size and shape on the water loss ratio were embodied in established model of averaged relative humidity improved by considering effects of sequential hydration and calculated by finite difference method. Furthermore, the effects of specimen size and shape on drying shrinkage strain of concrete were experimentally deduced and applied to modify criterion EB-FIP1990. The comparison between experimental and calculated results shows that the modified EB-FIP1990 can be adopted to predict drying shrinkage strain of concrete with reasonable accuracy.

Effects of site conditions on earthquake ground motion and their applications in seismic design in loess region

The Loess Plateau is an earthquake prone region of China, where the effects of loess deposit on ground motion were discovered during the 2008 Wenchuan earthquake(Ms8.0) and the 2013 Minxian-Zhangxian earthquake(Ms6.6). The field investigations, observations, and analyses indicated that large number of casualties and tremendous economic losses were caused not only by collapse and damage of houses with poor seismic performance, landslides, but also amplification effects of site conditions, topography and thickness of loess deposit, on ground motion. In this paper, we chose Dazhai Village and Majiagou Village as the typical loess site affected by the two earthquakes for intensity evaluation, borehole exploration, temporary strong motion array, micro tremor survey, and numerical analysis. The aim is to explore the relations between amplification factors and site conditions in terms of topography and thickness of loess deposit. We also developed site amplification factors of ground motion for engineering design consideration at loess sites. The results showed that the amplification effects are more predominant with increase in thickness of loess deposit and slope height. The amplification mayincrease seismic intensity by 1 degree, PGA and predominant period by 2 times, respectively.

Multitaper spectral method to estimate the elastic thickness of South China: Implications for intracontinental deformation

The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and topographic data. Studies of Te have profound influence on intracontinental deformation, and coupling of the tectonic blocks. In this paper, we use the multitaper spectral estimation method to calculate the coherence between Bouguer gravity and topography data, and to obtain the Te map of South China. Through the process of correction, we discuss the relationships of Te versus heat flow, and Te versus seismicity. The results show that Te distribution of South China is affected by three factors：the original age, which controls the basic feature;the Mesozoic evolution, which affects the Te distribution;and the neotectonic movement, which shaped the final distribution. The crust age has a positive correlation with the first-order Te distribution;thus the Yangtze Craton has a relatively higher Te （about 50 km） whereas the Te in Cathaysia block is only 10e20 km. By analysis and comparison among the tectonic models of South China, the Te distribution can be well explained using the flat-subduction model. As is typical with neotectonics, the region with a higher heat flow is related with a lower Te. The seismicity does not have a clear relationship with Te, but the strong seismicity could cause a low Te. Seismogenic layer （Ts） has a similar trend as Te in the craton, whereas in other areas the relationship is complex.