摘要：Light emitting diode （LED） sources have been widely used for illumination. Optical design, especially freedom compact lens design is necessary to make LED sources applied in lighting industry, such as large-range interior lighting and small-range condensed lighting. For different lighting requirements, the size of target planes should be variable. In our paper we provide a method to design freedom lens according to the energy conservation law and Snell law through establishing energy mapping between the luminous flux emitted by a Lambertian LED source and a certain area of the target plane. The algorithm of our design can easily change the radius of each circular target plane, which makes the size of the target plane adjustable. Ray-tracing software Tracepro is used to validate the illuminance maps and polar-distribution maps. We design lenses for different sizes of target planes to meet specific lighting requirements.

摘要：We have designed an air-bridged PhC microcavity with high sensitivity and a high quality *** structure parameters of the microcavity are optimized by three-dimensional finite-difference time-domain method. We compare the performance of a silicon-on-insulator PhC microcavity and an air-bridged PhC microcavity,and analyze the effect of the thickness of the slab and the radius of the defect hole on the performance of the air-bridged PhC *** a thinner slab and a larger defect hole,the sensitivity is higher while the quality factor is *** the air-bridged photonic crystal slab,the sensitivity can reach 320-nm/RIU（refractive index unit） while the quality factor keeps a relatively high value of 120 by selecting the proper slab thickness and the defect hole radius,respectively,when the refractive index is *** is meaningful for low-detection-limit biosensing.

摘要：Conceptual design, data model and key techniques of "Geo-engineer 3D assistant", an underground 3D GIS oriented to geology and mine application, were discussed. In particular, the importance of high-order smoothing triangular pieces to surface's fine expression in geological modeling was emphasized. The contour mode is the most favorite mode of the three modes about surface expression: DEM, TIN and contour. Topology in underground 3D modeling with CAGD was compared. From the view of boundary and coboundary, which is soul of IS 19107 (Geographic information spatial schema), 3D underground topology was re-examined.

摘要：We present the design and optimization of evanescently coupled waveguide photodiodes（EC-WPDs） based on the coupling modes theory and the beam propagation *** focalization of the optical power in the absorber is achieved by an appropriate choice of index matching layers of *** simulation shows that high-speed（40 GHz）,high quantum efficiency（81%） and high linearity photodiodes can be achieved, and EC-WPDs are promising devices for future optical communication systems.

摘要：We present a method to optimize the flat-band long-period fiber Bragg grating (FBG) in this *** method is based on the p^rticle swarm optimization method and the matrix transmission *** optimized refractive modulation profile does not introduce so many phase shifts and is easier to fabricate compared with that of layer-peeling method which introduces lots of π phase shift at each zero point of apodization profile in designing for the same problem.

摘要：Low-field nuclear magnetic resonance magnet（2 MHz） is required for rock core analysis. However, due to its low field strength, it is hard to achieve a high uniform B0 field only by using the passive shimming. Therefore, active shimming is necessarily used to further improve uniformity for Halbach magnet. In this work, an equivalent magnetic dipole method is presented for designing shim coils. The minimization of the coil power dissipation is considered as an optimal object to minimize coil heating effect, and the deviation from the target field is selected as a penalty function term. The lsqnonlin optimization toolbox of MATLAB is used to solve the optimization problem. Eight shim coils are obtained in accordance with the contour of the stream function. We simulate each shim coil by ANSYS Maxwell software to verify the validity of the designed coils. Measurement results of the field distribution of these coils are consistent with those of the target *** uniformity of the B0 field is improved from 114.2 ppm to 26.9 ppm after using these shim coils.

摘要：The conventional magnetic resonance imaging(MRI)equipment cannot measure large volume samples nondestructively in the engineering site for its heavy weight and closed *** order to realize the mobile MRI,this study focuses on the design of gradient coil of unilateral *** unilateral MRI system is used to image the local area above the *** current density distribution of the gradient coil cannot be used as a series of superconducting nuclear magnetic resonance gradient coils,because the region of interest(ROI)and the wiring area of the unilateral magnet are both cylindrical side arc ***,the equivalent magnetic dipole method is used to design the gradient coil,and the algorithm is improved for the special case of the wiring area and the ROI,so the X and Y gradient coils are ***,a flexible printed circuit board(PCB)is used to fabricate the gradient coil,and the magnetic field distribution of the ROI is measured by a Gauss meter,and the measured results match with the simulation *** gradient linearities of x and y coils are 2.82%and 3.56%,respectively,less than 5%of the commercial gradient coil requirement.

摘要：Anisotropic metamaterial with only one component of the mass density tensor near zero （ADNZ） is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the ＂T＂-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects.

摘要：A high detection efficiency calorimeter which is used to detect γ-rays with energies from 1 MeV up to 10 MeV as well as light charged particles has been proposed. Design of the geometry, results of the crystal tests and Monte Carlo simulations are presented in this paper. The simulation results confirm that the calorimeter can obtain high detection efficiency and good energy resolution with the current designed geometry. And the calorimeter is competent for the future External Target Facility （ETF） experiments.

摘要：the Information-Centric Networking(ICN) paradigm is proved to have the advantages of decreasing data delivery latency, enhancing user mobility, etc. However, current implementations of ICN require changing the infrastructure of Internet, which hinders its deployment and development. Meanwhile, Software Defined Networking(SDN) emerges as a viable solution to facilitate the deployment of new network paradigm without disrupting production traffic by decoupling the control plane from data forwarding plane. In this paper, the essential properties which reflect ICN working principles are summarized, and a framework called SDICN is designed in accordance to the SDN philosophy. The algorithmic frameworks of SDICN which can satisfy the essential properties are designed based on the programmability and virtualization functions of SDN. Based on Open Flow and data center technology, a prototype of SDICN is implemented. By comparing the performance with the CCNx, the SDICN is proved to be feasibility and availability.