We propose a model which includes a nearest-neighbor intrinsic spin-orbit coupling and a trimerized Hamiltonian in the Kagomé lattice and promises to host the transition from the quantum spin Hall insulator to the normal insulator. In addition, we design an experimental scheme to simulate and detect this transition in the ultracold atom system. The lattice intrinsic spin-orbit coupling is generated via the laser-induced-gauge-field method. Furthermore, we establish the connection between the spin Chern number and the spin-atomic density which enables us to detect the quantum spin Hall insulator directly by the standard density-profile technique used in the atomic systems.

We investigate the nonlinear dynamics of a combined system which is composed of a cigar-shaped BoseEinstein condensate and an optical cavity with the two sides coupled dispersively. This system is characterized by the cavity-induced nonlinearity; after integrating out the fast degree of freedom of the cavity mode, the potential felt by the condensate depends on the condensate itself. Adopting a discrete-mode approximation for the condensate, we map out the steady configurations of the system. It is found that due to the nonlinearity of the system, the nonlinear levels of the system may fold up in some parameter regimes. That will lead to the breakdown of adiabatic evolution of the system. Analysis of the dynamical stability of the steady states indicates that the same level structure also results in optical bistability.

The majority of cases of placenta accreta are unanticipated and initially identified intraoperatively. Although color Doppler ultrasound is adequate for the evaluation of placenta accreta in the third trimester, ultrasound diagnosis in the first trimester has never been reported. To our knowledge, this is the first case of placenta accreta detected at 9 weeks' gestation by ultrasound. Placenta accreta with intraplacental lacunae can be identified together with a loss of the hypoechogenic retroplacental myometrial zone. Based on this case, we found that early diagnosis of placenta accreta in the first trimester by ultrasound is possible.

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Magnetic solitons in spinor Bose-Einstein condensates confined in a one-dimensional optical lattice are studied by the Holstein-Primakoff transformation method. It is shown that due to the long-range light-induced and static magnetic dipole-dipole interactions, there exist different types of magnetic solitary excitations in different parameter regions. Compared to conventional solid-state materials, the parameters of this type of magnetic solitons in an optical lattice can be easily tuned by the above dipole-dipole interactions, which are highly controllable in experiments.

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We present two families of analytical solutions of the one-dimensional nonlinear Schrödinger equation, which describe the dynamics of bright and dark solitons in Bose-Einstein condensates ͑BECs͒ with the timedependent interatomic interaction in an expulsive parabolic and complex potential. We also demonstrate that the lifetime of both a bright soliton and a dark soliton in BECs can be extended by reducing both the ratio of the axial oscillation frequency to radial oscillation frequency and the loss of atoms. It is interesting that a train of bright solitons may be excited with a strong enough background. An experimental protocol is further designed for observing this phenomenon.