Characteristics and influencing mechanisms of production-living-ecological space dynamics in the Three Gorges Reservoir Area(TGRA),Chongqing,China

The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of production-living-ecological spaces for sustainable and high-quality development in the TGRA.This study investigated the dynamic variation of production-living-ecological spaces in the TGRA by employing land use data in 2000,2005,2010,2015,and 2018,and detected the influencing factors by using the Geographic detector(GeoDetector).Results implied that the structure and dynamic trajectories of production-living-ecological spaces in the TGRA varied in both horizontal and vertical directions,and the study area was dominated by ecological space.A spatial orientation towards the northeast was detected in the evolution of production-living-ecological spaces during 2000-2018.In terms of quantity,the transition from ecological space(grassland and woodland)to agriculture land accounted for the largest proportion from 2000 to 2018.However,the reverse transition from agriculture land to ecological space has increased since 2000 with the efforts of“Grain for Green”.In terms of temporal scale,there was a fluctuating trend in production space with the continuous expansion of living space,while ecological space showed an inverted U-shaped trend during 2000-2018.The dynamic pattern of production-living-ecological spaces in the TGRA was influenced by both physical and socio-economic variables as basic determinants and dominant driving factors,respectively.Finally,the harmonization and protection of production-living-ecological spaces still require policy-makers’efforts.This work may have potential in advancing our understanding about land use conflicts,and provide a reference for rational layout of spatial functions and the realization of sustainable development in the TGRA.

THE ANALYTICAL PROPERTIES FOR HOMOGENEOUS RANDOM TRANSITION FUNCTIONS

The concepts of Markov process in random environment and homogeneous random transition functions are introduced. The necessary and sufficient conditions for homogeneous random transition function are given. The main results in this article are the analytical properties, such as continuity, differentiability, random Kolmogorov backward equation and random Kolmogorov forward equation of homogeneous random transition functions.

Functional transition:Inconsistently parallel to the increase in future liver remnant volume after preoperative portal vein embolization

BACKGROUND Preoperative portal vein embolization(PVE)is a widely used strategy to enable major hepatectomy in patients with insufficient liver remnant.PVE induces hypertrophy of the future liver remnant(FLR)and a shift of the functional reserve to the FLR.However,whether the increase of the FLR volume(FLRV)corresponds to the functional transition after PVE remains unclear.AIM To investigate the sequential relationship between the increase in FLRV and functional transition after preoperative PVE using 3-dimensional(3D)computed tomography(CT)and 99mTc-galactosyl-human serum albumin(99mTc-GSA)singlephoton emission computed tomography(SPECT)fusion images.METHODS Thirty-three patients who underwent major hepatectomy following PVE at the Department of Gastroenterological Surgery I,Hokkaido University Hospital between October 2013 and March 2018 were enrolled.Three-phase dynamic multidetector CT and 99mTc-GSA SPECT scintigraphy were performed at pre-PVE,and at 1 and 2 wk after PVE;3D 99mTc-GSA SPECT CT-fused images were constructed from the Digital Imaging and Communications in Medicine data using 3D image analysis system.Functional FLRV(FFLRV)was defined as the total liver volume×(FLR volume counts/total liver volume counts)on the 3D 99m Tc-GSA SPECT CT-fused images.The calculated FFLRV was compared with FLRV.RESULTS FFLRV increased by a significantly larger extent than FLRV at 1 and 2 wk after PVE(P<0.01).The increase in FFLRV and FLRV was 55.1%±41.6%and 26.7%±17.8%(P<0.001),respectively,at 1 wk after PVE,and 64.2%±33.3%and 36.8%±18.9%(P<0.001),respectively,at 2 wk after PVE.In 3 of the 33 patients,FFLRV levels decreased below FLRV at 2 wk.One of the three patients showed rapidly progressive fatty changes in FLR.The biopsy at 4 wk after PVE showed macroand micro-vesicular steatosis of more than 40%,which improved to 10%.Radical resection was performed at 13 wk after PVE.The patient recovered uneventfully without any symptoms of pos-toperative liver failure.CONCLUSION The functional transition lagged behind the increase in FLRV after PVE in some cases.Evaluating both volume and function is needed to determine the optimal timing of hepatectomy after PVE.

Theoretical Study on the C-H Activation in Decarbonylation of Acetaldehyde by NiL_2(L=SO_3CH_3) Using Density Functional Theory

Density functional theory calculations were carried out to explore the potential energy surface（PES） associated with the gas-phase reaction of Ni L2（L=SO3CH3） with acetone. The geometries and energies of the reactants, intermediates, products and transition states of the triplet ground potential energy surfaces of [Ni, O, C2, H4] were obtained at the B3LYP/6-311＋＋G（d,p） levels in C,H,O atoms and B3LYP/ Lanl2 dz in Ni atom. It was found through our calculations that the decabonylation of acetaldehyde contains four steps including encounter complexation, C-C activation, aldehyde H-shift and nonreactive dissociation. The results revealed that C-C activation induced by Ni L2（L=SO3CH3） led to the decarbonylation of acetaldehyde.

Second-Order Correlation Function for Asymmetric-to-Symmetric Transitions due to Spectrally Indistinguishable Biexciton Cascade Emission

We report the observed photon bunching statistics of biexciton cascade emission at zero time delay in single quantum dots by second-order correlation function g（2） （T） measurements under continuous wave excitation. It is found that the bunching phenomenon is independent of the biexciton binding energy when it varies from 0.59 meV to nearly zero. The photon bunching takes place when the exeiton photon is not spectrally distinguishable from the biexciton photon, and either of them can trigger the %tart＇ in a Hanbury-Brown and Twiss setup. However, if the exciton energy is spectrally distinguishable from the biexciton, the photon statistics will become asymmetric and a cross-bunching lineshape can be obtained. The theoretical calculations based on a model of three-level rate-equation analysis are consistent with the result of g（2）（τ） correlation function measurements.

Influence of Different Transition Modes on the Performances of a Hydraulic Turbine

In order to analyze the response of a hydraulic turbine to a variation in the operating conditions,different laws of variation in time of the massflow rate have been considered.After validating the overall numerical framework through comparison with relevant experiments,the performances of the considered turbine have been analyzed from afluid-dynamic point of view.The results show that different time profiles of the massflow rate(in this work,for simplicity,referred to as“transition functions”)have a varying influence on the transient behavior of the turbine.When a quadratic function is considered for the case of largeflow,the transient head and torque increase gradually with time,thefluctuation amplitude of the transient hydraulic efficiency at the main frequency is the largest,and thefluctuation amplitude of the radial force is the smallest.For the smallflow case,the time profile with exponential nature leads to the best results.The transient head and torque decrease gradually with time,the pulsation amplitude of the transient hydraulic efficiency is the largest at the main frequency,and the pulsation amplitude of the radial force is the smallest.

Laplace Transformation and Ergodic Potential Kernel for q-Process in Random Environment

This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation of random transition function. Finally, we give the sufficient condition for the existence of ergodic potential kernel for homogeneous q- processes in random environments.

Theoretical and Experimental Studies on the Reaction Mechanism of Cl_2 + I_2 = 2ICl

The gas phase reaction mechanism of Cl2 ＋ I2 = 2ICl has been theoretically investigated by DFF method at the B3LYP/3-21 G＊ level. Transition states of three reaction channels were consequently given. The results indicate that in the title reaction the least activation energy of bi-molecular reaction was smaller than the dissociation energies of I2 and Cl2, and thus the reaction mechanism was the course of molecule-molecule interaction at low reaction rate. If other factors such as illumination were taken into account, I2 could dissociate into I atoms and then react with Cl2, or Cl2 dissociates into CI atoms and reacts with I2. These were photochemical reactions with high reaction speed. The theoretical results were further validated with absorbance measurement at 516 nm.

Tunable Electronic and Magnetic Properties from Structure Phase Transition of Layered Vanadium Diselenide

The atomic geometry, structure stability, electronic and magnetic properties of VSe2 were systematically investigated based on the density functional theory（DFT）. Varying from 3D to 2D four VSe2 structures, bulk 2H-VSe2 and 1T-VSe2, monolayer H-VSe2 and T-VSe2 are all demonstrated as thermodynamically stable by lattice dynamic calculations. More interestingly, the phase transition temperature is dramatically different due to the lattice size. Finally, owing to different crystal structures, H-VSe2 is semimetallic whereas T-VSe2 is totally metallic and also they have different magnetic moments. Our main argument is that being exfoliated from bulk to monolayer, 2H-VSe2 transforms to T-VSe2, accompanied by both semimetallic-metallic transition and dramatic magnetic moment variation. Our calculations provide a novel structure phase transition and an efficient way to modulate the electronic structure and magnetic moment of layered VSe2, which suggests potential applications as high-performance functional nanomaterial.

THE BRANCHING CHAIN WITH DRIFT IN SPACE-TIME RANDOM ENVIRONMENT(I):MODEL,MARKOV PROPERTY,MOMENTS

There are three parts in this article. In Section 1, we establish the model of branching chain with drift in space-time random environment （BCDSTRE）, i.e., the coupling of branching chain and random walk. In Section 2, we prove that any BCDSTRE must be a Markov chain in time random environment when we consider the distribution of the particles in space as a random element. In Section 3, we calculate the first-order moments and the second-order moments of BCDSTRE.

METABALL-BASED TRANSITION SURFACES

Metaball-based constraint deformation technique is used to change the definition of r, the straight-line distance from a space point to a constraint center in the original calculation of the potential function. By replacing the parameter of the pararnetrized surface w with the straight-line distance r, a method of building transition surfaces according to cormected boundary curves and skeleton curves is proposed. The method has no restrictions on boundary curves that control the space shapes of transition surfaces or on types of skeleton curves, thus transition surfaces, which reach C^1 continuity and are more abundant in shapes and natural, can be obtained.

Construction and Regularity of Transition Functions on Polish Spaces under Measurability Conditions

This paper concerns the construction and regularity of a transition （probability） function of a nonhomogeneous continuous-time Maxkov process with given transition rates and a general state space. Motivating from a lot of restriction in applications of a transition function with continuous （in t ≥0） and consewative transition rates q（t, x, A）, we consider the case that q（t, x, A） axe only required to satisfy a mild measurability （in t ≥ O） condition, which is a generalization of the continuity condition. Under the measurability condition we construct a transition function with the given transition rates, provide a necessary and sufficient condition for it to be regular, and further obtain some interesting additional results.

Contraction Integrated Semigroups and Their Applicationto Continuous-time Markov Chains

We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their application, a necessary and sufficient condition for q-matrices Q generating a contraction integrated semigroup is given, and a necessary and sufficient condition for a transition function to be a Feller-Reuter-Riley transition function is also given in terms of its q-matrix.

Semi-tensor product of matrices approach to reachability of finite automata with application to language recognition

This paper investigates the transition function and the reachability conditions of finite automata by using a semitensor product of matrices, which is a new powerful matrix analysis tool. The states and input symbols are first expressed in vector forms, then the transition function is described in an algebraic form. Using this algebraic representation, a sufficient and necessary condition of the reachability of any two states is proposed, based on which an algorithm is developed for discovering all the paths from one state to another. Furthermore, a mechanism is established to recognize the language acceptable by a finite automaton. Finally, illustrative examples show that the results/algorithms presented in this paper are suitable for both deterministic finite automata （DFA） and nondeterministic finite automata （NFA）.

Parametric estimation of discretely sampled Gamma-OU processes

The stationary Gamma-OU processes are recommended to be the volatility of the financial assets. A parametric estimation for the Gamma-OU processes based on the discrete observations is considered in this paper. The estimator of an intensity parameter A and its convergence result are given, and the simulations show that the estimation is quite accurate. Assuming that the parameter A is estimated, the maximum likelihood estimation of shape parameter c and scale parameter a, whose likelihood function is not explicitly computable, is considered. By means of the Gaver-Stehfest algorithm, we construct an explicit sequence of approximations to the likelihood function and show that it converges the true (but unkown) one. Maximizing the sequence results in an estimator that converges to the true maximum likelihood estimator and the approximation shares the asymptotic properties of the true maximum likelihood estimator. Some simulation experiments reveal that this method is still quite accurate in most of rational situations for the background of volatility.

Numerical analysis and optimization of boundary layer suction on airfoils

Numerical approach of hybrid laminar flow control （HLFC） is investigated for the suc- tion hole with a width between 0.5 mm and 7 mm. The accuracy of Menter and Langtry＇s transition model applied for simulating the flow with boundary layer suction is validated. The experiment data are compared with the computational results. The solutions show that this transition model can pre- dict the transition position with suction control accurately. A well designed laminar airfoil is selected in the present research. For suction control with a single hole, the physical mechanism of suction control, including the impact of suction coefficient and the width and position of the suc- tion hole on control results, is analyzed. The single hole simulation results indicate that it is favor- able for transition delay and drag reduction to increase the suction coefficient and set the hole position closer to the trailing edge properly. The modified radial basis function （RBF） neural net- work and the modified differential evolution algorithm are used to optimize the design for suction control with three holes. The design variables are suction coefficient, hole width, hole position and hole spacing. The optimization target is to obtain the minimum drag coefficient. After optimization, the transition delay can be up to 17% and the aerodynamic drag coefficient can decrease by 12.1%.

Convergence rate of Gibbs sampler and its application

Based on the convergence rate defined by the Pearson-χ~2 distance,this pa- per discusses properties of different Gibbs sampling schemes.Under a set of regularity conditions,it is proved in this paper that the rate of convergence on systematic scan Gibbs samplers is the norm of a forward operator.We also discuss that the collapsed Gibbs sam- pler has a faster convergence rate than the systematic scan Gibbs sampler as proposed by Liu et al.Based on the definition of convergence rate of the Pearson-χ~2 distance, this paper proved this result quantitatively.According to Theorem 2,we also proved that the convergence rate defined with the spectral radius of matrix by Robert and Shau is equivalent to the corresponding radius of the forward operator.

A geometric interpretation of the transition density of a symmetric Lévy process

We study for a class of symmetric Levy processes with state space R^n the transition density pt（x） in terms of two one-parameter families of metrics, （dt）t〉o and （δt）t〉o. The first family of metrics describes the diagonal term pt （0）; it is induced by the characteristic exponent ψ of the Levy process by dr（x, y） = √tψ（x - y）. The second and new family of metrics 6t relates to √tψ through the formula exp（-δ^2t（x,y））=F[e^-tψ/pt（0）]（x-y）,where Y denotes the Fourier transform. Thus we obtain the following ＂Gaussian＂ representation of the tran- sition density： pt（x） = pt（O）e^-δ^2t（x,0） where pt（O） corresponds to a volume term related to √tψ and where an ＂exponential＂ decay is governed by 5t2. This gives a complete and new geometric, intrinsic interpretation of pt（x）.

Siegmund Duality for Continuous Time Markov Chains on Z_+~d

For the continuous time Markov chain with transition function P（t） on Z d ＋ , we give the necessary and sufficient conditions for the existence of its Siegmund dual with transition function P - （t）. If Q, the q-matrix of P（t）, is uniformly bounded, we show that the Siegmund dual relation can be expressed directly in terms of q-matrices, and a sufficient condition under which the Q-function is the Siegnmnd dual of some Q-function is also given.

Heat Kernel Estimates for Non-symmetric Finite Range Jump Processes

In this paper,we first establish the sharp two-sided heat kernel estimates and the gradient estimate for the truncated fractional Laplacian under gradient perturbation S^(b):=△^(α/2)+b·▽,where △^(α/2) is the truncated fractional Laplacian,α∈(1,2) and b ∈ K_(d)^(α-1).In the second part,for a more general finite range jump process,we present some sufficient conditions to allow that the two sided estimates of the heat kernel are comparable to the Poisson type function for large distance |x-y|in short time.