The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin, northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Ol...The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin, northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Oligocene-Quaternary supra-salt sequence. The salt sequence is composed mainly of light grey halite, gypsum, marl and brown elastics. A variety of salt-related structures have developed in the Kuqa foreland fold belt, in which the most fascinating structures are salt nappe complex. Based on field observation, seismic interpretation and drilling data, a large-scale salt nappe complex has been identified. It trends approximately east-west for over 200 km and occurs along the west Qiulitag Mountains. Its thrusting displacement is over 30 km. The salt nappe complex appears as an arcuate zone projecting southwestwards along the leading edge of the Kuqa foreland fold belt. The major thrust fault is developed along the Paleocene-Eocene salt beds. The allochthonous nappes comprise large north-dipping faulting monoclines which are made up of Paleocene-Pliocene sediments. Geological analysis and cross-section restoration revealed that the salt nappes were mainly formed at the late Himalayan stage (c.a. 1.64 Ma BP) and have been active until the present day. Because of inhomogeneous thrusting, a great difference may exist in thrust displacement, thrust occurrence, superimposition of allochthonous and autochthonous sequences and the development of the salt-related structures, which indicates the segmentation along the salt nappes. Regional compression, gravitational gliding and spreading controlled the formation and evolution of the salt nappe complex in the Kuqa foreland fold belt.展开更多
In this paper, optimal investment and consumption decisions for an optimal choice problem in infinite horizon are considered, for an investor who has available a bank account and a stock whose price is a log normal di...In this paper, optimal investment and consumption decisions for an optimal choice problem in infinite horizon are considered, for an investor who has available a bank account and a stock whose price is a log normal diffusion. The bank pays at an interest rate r for any deposit, and takes at a larger rate r′ for any loan. As in the paper of Xu Wensheng and Chen Shuping in JAMS(B), where an analogous problem in finite horizon is studied, optimal strategies are obtained via Hamilton Jacobi Bellman (HJB) equation which is derived from dynamic programming principle. For the specific HARA case, i.e. U(t,c)=e -βt c 1-R 1-R , this paper gets the optimal consumption and optimal investment in the form ofc * t=β-Rw t\ and \ π * t=b-γRσ 2w twith γ:= max{ r, min{ r′,b-Rσ 2 }}, =(1-R)γ+(b-γ) 22Rσ 2]. This result coincides with the classical one under condition r′≡r.展开更多
This paper studies a stochastic linear quadratic optimal control problem (LQ problem, for short), for which the coefficients are allowed to be random and the cost functional is allowed to have a negative weight on the...This paper studies a stochastic linear quadratic optimal control problem (LQ problem, for short), for which the coefficients are allowed to be random and the cost functional is allowed to have a negative weight on the square of the control variable. The authors introduce the stochastic Riccati equation for the LQ problem. This is a backward SDE with a complicated nonlinearity and a singularity. The local solvability of such a backward SDE is established, which by no means is obvious. For the case of deterministic coefficients, some further discussions on the Riccati equations have been carried out. Finally, an illustrative example is presented.展开更多
基金This research received financial supports from the National Natural Science Foundation of China(grant 40172076)the National Major Fundamental Research and Development Project(grant G1999043305)the National Key Project of the Ninth Five—Year Plan(grant 99—1111)
文摘The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin, northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Oligocene-Quaternary supra-salt sequence. The salt sequence is composed mainly of light grey halite, gypsum, marl and brown elastics. A variety of salt-related structures have developed in the Kuqa foreland fold belt, in which the most fascinating structures are salt nappe complex. Based on field observation, seismic interpretation and drilling data, a large-scale salt nappe complex has been identified. It trends approximately east-west for over 200 km and occurs along the west Qiulitag Mountains. Its thrusting displacement is over 30 km. The salt nappe complex appears as an arcuate zone projecting southwestwards along the leading edge of the Kuqa foreland fold belt. The major thrust fault is developed along the Paleocene-Eocene salt beds. The allochthonous nappes comprise large north-dipping faulting monoclines which are made up of Paleocene-Pliocene sediments. Geological analysis and cross-section restoration revealed that the salt nappes were mainly formed at the late Himalayan stage (c.a. 1.64 Ma BP) and have been active until the present day. Because of inhomogeneous thrusting, a great difference may exist in thrust displacement, thrust occurrence, superimposition of allochthonous and autochthonous sequences and the development of the salt-related structures, which indicates the segmentation along the salt nappes. Regional compression, gravitational gliding and spreading controlled the formation and evolution of the salt nappe complex in the Kuqa foreland fold belt.
文摘In this paper, optimal investment and consumption decisions for an optimal choice problem in infinite horizon are considered, for an investor who has available a bank account and a stock whose price is a log normal diffusion. The bank pays at an interest rate r for any deposit, and takes at a larger rate r′ for any loan. As in the paper of Xu Wensheng and Chen Shuping in JAMS(B), where an analogous problem in finite horizon is studied, optimal strategies are obtained via Hamilton Jacobi Bellman (HJB) equation which is derived from dynamic programming principle. For the specific HARA case, i.e. U(t,c)=e -βt c 1-R 1-R , this paper gets the optimal consumption and optimal investment in the form ofc * t=β-Rw t\ and \ π * t=b-γRσ 2w twith γ:= max{ r, min{ r′,b-Rσ 2 }}, =(1-R)γ+(b-γ) 22Rσ 2]. This result coincides with the classical one under condition r′≡r.
基金the National Natural Science Foundation of China!(No.7979D130), theNational Distinguished Youth Science Foundation of China (N
文摘This paper studies a stochastic linear quadratic optimal control problem (LQ problem, for short), for which the coefficients are allowed to be random and the cost functional is allowed to have a negative weight on the square of the control variable. The authors introduce the stochastic Riccati equation for the LQ problem. This is a backward SDE with a complicated nonlinearity and a singularity. The local solvability of such a backward SDE is established, which by no means is obvious. For the case of deterministic coefficients, some further discussions on the Riccati equations have been carried out. Finally, an illustrative example is presented.
