Use of negative capacitance to simulate the electrical characteristics in double-gate ferroelectric field-effect transistors

Y.G. Xiao,M.H. Tang,Y. Xiong,J. C. Lin,C.P. Cheng,B. Jiang,H.Q. Cai,Z.H. Tang,X.S. Lv,X.C. Gu,Y.C. Zhou 한국물리학회 2012 Current Applied Physics Vol.12 No.6

The surface potential and drain current of double-gate metal-ferroelectric-insulator-semiconductor (MFIS) field-effect transistor were investigated by using the ferroelectric negative capacitance. The derived results demonstrated that the up-converted semiconductor surface potential and low subthreshold swing S = 34 (<60 mV/dec) can be realized with appropriate thicknesses of ferroelectric thin film and insulator layer at room temperature. What’s more, a reduction gate voltage about 260 mV can be reached if the ON-state current is fixed to 600 mA/mm. It is expected that the derived results can offer useful guidelines for the application of low power dissipation in ongoing scaling of FETs.

A novel evidence theory model and combination rule for reliability estimation of structures

Y.R. Tao,Q. Wang,L. Cao,S.Y. Duan,Z.H.H. Huang,G.Q. Cheng 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.4

Due to the discontinuous nature of uncertainty quantification in conventional evidence theory(ET), the computational cost of reliability analysis based on ET model is very high. A novel ET model based on fuzzy distribution and the corresponding combination rule to synthesize the judgments of experts are put forward in this paper. The intersection and union of membership functions are defined as belief and plausible membership function respectively, and the Murfhy’s average combination rule is adopted to combine the basic probability assignment for focal elements. Then the combined membership functions are transformed to the equivalent probability density function by a normalizing factor. Finally, a reliability analysis procedure for structures with the mixture of epistemic and aleatory uncertainties is presented, in which the equivalent normalization method is adopted to solve the upper and lower bound of reliability. The effectiveness of the procedure is demonstrated by a numerical example and an engineering example. The results also show that the reliability interval calculated by the suggested method is almost identical to that solved by conventional method. Moreover, the results indicate that the computational cost of the suggested procedure is much less than that of conventional method. The suggested ET model provides a new way to flexibly represent epistemic uncertainty, and provides an efficiency method to estimate the reliability of structures with the mixture of epistemic and aleatory uncertainties.

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

Zhao, K.J.,Nagashima, Y.,Li, F.M.,Shi, Yuejiang,Diamond, P.H.,Dong, J.Q.,Itoh, K.,Itoh, S.-I.,Zhuang, G.,Liu, H.,Chen, Z.P.,Cheng, J.,Nie, L.,Ding, Y.H.,Hu, Q.M.,Chen, Z.Y.,Rao, B.,Cheng, Z.F.,Gao, L. IOP 2017 Nuclear fusion Vol.57 No.12

<P>The temporal-spatial structures of plasma flows and turbulence around tearing mode islands are presented. The experiments were performed using Langmuir probe arrays in the edge plasmas of J-TEXT tokamak. The correlation analyses clearly show that the flows have similar structures of <I>m</I>/<I>n</I>  =  3/1 as the magnetic island does (<I>m</I> and <I>n</I> are the poloidal and toroidal mode numbers, respectively). The sign of the potential fluctuations for the flows inverses and the powers significantly reduce at <I>q</I>  =  3 surface. Approaching to the last closed flux surface for the magnetic islands, the radially elongated flow structure forms. The flows are concentrated near separatrix and show quadrupole structures. The turbulence is concentrated near X-point and partly trapped inside the magnetic islands.</P>

Association among self-compassion, resilience and positive mental health and risk of gaming disorder in 18-30 years old Asian population

Tang, A.C.Y.,Lee, R.L.T.,Lee, P. H.,Cheng, W.L.S.,Chan, S.,Guo, Y.,Wang, Y.,Wang, Q.,Wongchaiya, P.,Suen, L.K.P. 한국간호과학회 2023 한국간호과학회 학술대회 Vol.2023 No.11

One Alpha-hydroxycholecalciferol Improves Growth Performance, Tibia Quality, and Meat Color of Broilers Fed Calcium- and Phosphorus-Deficient Diets

Han, J.C.,Wang, Y.L.,Qu, H.X.,Liang, F.,Zhang, J.L.,Shi, C.X.,Zhang, X.L.,Li, L.,Xie, Q.,Wang, C.L.,Yan, Y.Y.,Dong, X.S.,Cheng, Y.H. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.2

An experiment was conducted to evaluate the effects of one alpha-hydroxycholecalciferol ($1{\alpha}$-OH $D_3$) on growth performance, tibia quality, and skin and meat color in broilers fed calcium (Ca)- and phosphorus (P)-deficient corn-soybean meal diets. A total of 288 male Ross broilers, at 21 days of age, were randomly assigned to three treatments with eight cages per treatment. Three levels of $1{\alpha}$-OH $D_3$ (0, 5, and 10 ${\mu}g$/kg) were added to a basal diet (0.50% Ca, 0.13% non-phytate phosphorus (NPP), and 0.35% total phosphorus (tP)) without vitamin $D_3$. As a result of this study, the addition of $1{\alpha}$-OH $D_3$ increased body weight gain (p<0.001), feed intake (p = 0.007), feed efficiency (p<0.001), tibia weight (p = 0.002), length (p<0.001), breaking-strength (p = 0.012), ash (p<0.001), Ca (p<0.001), and P content (p = 0.004). Dietary $1{\alpha}$-OH $D_3$ enhanced breast meat yellowness (p = 0.015) and the length and weight of the small intestine of the broilers. Moreover, $1{\alpha}$-OH $D_3$ decreased serum Ca concentration (p = 0.074) and breast meat redness (p = 0.010). These results indicate that the $1{\alpha}$-OH $D_3$ improves growth, tibia quality, and meat color in broilers fed Ca- and P-deficient corn-soybean meal diets.

Response of plasma rotation to resonant magnetic perturbations in J-TEXT tokamak

Yan, W,Chen, Z Y,Huang, D W,Hu, Q M,Shi, Y J,Ding, Y H,Cheng, Z F,Yang, Z J,Pan, X M,Lee, S G,Tong, R H,Wei, Y N,Dong, Y B IOP 2018 Plasma physics and controlled fusion Vol.60 No.3

<P>The response of plasma toroidal rotation to the external resonant magnetic perturbations (RMP) has been investigated in Joint Texas Experimental Tokamak (J-TEXT) ohmic heating plasmas. For the J-TEXT’s plasmas without the application of RMP, the core toroidal rotation is in the counter-current direction while the edge rotation is near zero or slightly in the co-current direction. Both static RMP experiments and rotating RMP experiments have been applied to investigate the plasma toroidal rotation. The core toroidal rotation decreases to lower level with static RMP. At the same time, the edge rotation can spin to more than 20 km s<SUP>−1</SUP> in co-current direction. On the other hand, the core plasma rotation can be slowed down or be accelerated with the rotating RMP. When the rotating RMP frequency is higher than mode frequency, the plasma rotation can be accelerated to the rotating RMP frequency. The plasma confinement is improved with high frequency rotating RMP. The plasma rotation is decelerated to the rotating RMP frequency when the rotating RMP frequency is lower than the mode frequency. The plasma confinement also degrades with low frequency rotating RMP.</P>

Experimental study on fabrication and evaluation of a micro-scale shaft grinding tool

Y. D. Gong,X. L. Wen,J. Cheng,G. Q. Yin,C. Wang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3

This paper presents a micro-grinding experiment on AISI 1020 steel and Ti-6Al-4V to study micro-grinding principle and the changerule of the force and surface with different grinding parameters. A novel micro shaft grinding tool is fabricated by cold sprayed withCBN grains, the manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surfacequality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaftgrinding tool, the roughness of AISI 1020 steel accomplished in the experiment is about 0.086 μm. Measured micro-grinding force of Ti-6Al-4V decreases with the increasing spindle speed and the decreasing cutting depth. The surface roughness decreases with the increasingspindle speed and the decreasing feed rate. The minimum surface roughness is 325 nm with the spindle speed of 48000 r/min and thefeed rate of 20 μm/s.

Safety Analysis of Structures with Probability and Evidence Theory

Y. R. Tao,L. Cao,G. Q. Cheng,ZH. H. Huang 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

In safety analysis of structures, classical probabilistic analysis has been a popular approach in engineering. However, it is not always to obtain sufficient information to model all uncertain parameters of structures system by probability theory, especially at early stage of design. Under this circumstance, probability theory (used to model random uncertainty) combined with evidence theory (used to model epistemic uncertainty) may be utilized in safety analysis of structures. This paper proposed a novel method for safety analysis of structures based on probability and evidence theory. Firstly, Bayes conversion method is used as the way for precision of evidence body, and the mean and variance of epistemic uncertain variables is defined. Then epistemic uncertainty variables is transformed to normal random variables by reflection transformation method, and the checking point method (J-C method) is used to solve most probability point and reliability. A numerical example and two engineering examples are given to demonstrate the performance of the proposed method. The results show both precision and computational efficiency of the method is high. Moreover, the proposed method provides basis for reliability-based optimization with the hybrid uncertainties.

Research on simulation and experiment for surface topography machined by a novel point grinding wheel

Y. D. Gong,G. Q. Yin,X. L. Wen,M. Han,J. B. Yan,J. Cheng 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

Grains motion path will be changed in the point grinding process due to the existence of variable angle α. To verify the difference betweenpoint grinding and traditional grinding, the moving relationship and coordinate transformation between grinding wheel and workpieceare used to put the grain movement function equivalent to parabola, then point grinding cutting path is concluded. Based on grainsdistribution on the grinding wheel surface, the 3D geometry simulation topography of workpiece is obtained by extending the effectiveinterference trails along the axial direction. Furthermore, a vitrified bond CBN wheel with a coarse grinding area angle θ is proposed andthe principle of design and preparation of these novel grinding wheels are studied. The typical processing parameters are chosen to grindQT700 ladder shaft; the simulation results are verified by using the VHX-1000E microscope and the non-contact 3D surface profilometerto observe the workpiece surface topography and measure the surface roughness. The results indicated that the simulation microstructurescoincide well with the experimental measurements and the values of simulation roughness are 0.5 times of experiments. So, the geometricsimulation model provided an auxiliary and prediction method for the actual processing topography analysis. In addition, grindingwheels with different θ are used to grind ladder shafts with a series of grinding parameters. The influence trend of inclining angle α, cuttingdepth ap, axial feeding speed vf and grinding wheel speed vs on surface roughness is obtained. It is concluded that the values ofworkpiece surface roughness using novel grinding wheel are less than using the traditional grinding wheel under the condition of thesame processing parameters.

Research on force and temperature characteristics of novel point grinding wheels

G. Q. Yin,Y. D. Gong,Y. W. Li,J. Cheng 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8

We propose a novel point grinding wheel (NPGW) with coarse grinding zone angle θ. According to earlier studies, this type of grinding wheel has high grinding efficiency, long service life, and generates very little surface roughness. The contact zone between the grinding wheel and workpiece is modified by the addition of the NPGW with the coarse grinding zone angle θ and the inclined angle α of point grinding process, and as a result, grinding force and grinding zone temperature are also altered. The grinding force theoretical model of NPGW was established and the grinding zone temperature was simulated by the finite element method, based on the theory of grinding heat generation and distribution and triangular heat source distribution model. At the same time, seven pieces of NPGW with different angles θ used for grinding experiments were fabricated. The theoretical model of grinding force and the simulation of grinding temperature coincided with experimental results. Therefore, the grinding force theoretical model and the grinding temperature simulation provide an auxiliary and predictive method for the actual process. Moreover, the influence of parameters on grinding force and grinding zone temperature can be obtained, and the results indicate that the NPGW and point grinding process can reduce grinding force and grinding zone temperature. Finally, plastic deformation is attributed to the production of compressive stress and grinding heat is attributed to the production of tensile stress. Therefore, the residual stress is influenced by the grinding force and the grinding temperature coupled. The residual stress of workpiece surface and subsurface was studied. In conclusion, the NPGW and point grinding process can reduce residual stress of workpiece surface and subsurface, in the case of tensile and compressive stress.