The paper proposes a catadioptric infrared dual band optical system based on catadioptric configuration and optically passive athermal design method. The system shares primary mirror, secondary mirror and collimating lens group, and achieves abruption in longwave infrared and midwave infrared using a dichroic beam splitter. The influence of temperature on optical parameters, the design theory and design method are analyzed. A design example is presented. The detailed optimization design method and some considering factors in engineering design moment are discussed. The design results illustrate that the system can obtain good image quality in environment temperature of 10–40?°C, which could satisfy the design requirement. The actual test result not only satisfies the design requirement, but also validates the availability of the method in the paper. 相似文献
For any given matrix $A∈\mathbb{C}^{n×n}$, a preconditioner $t_U(A)$ called the superoptimal preconditioner was proposed in 1992 by Tyrtyshnikov. It has been shown that $t_U(A)$ is an efficient preconditioner for solving various structured systems, for instance, Toeplitz-like systems. In this paper, we construct the superoptimal preconditioners for different functions of matrices. Let $f$ be a function of matrices from$\mathbb{C}^{n×n}$ to$\mathbb{C}^{n×n}$. For any $A∈\mathbb{C}^{n×n}$, one may construct two superoptimal preconditioners for $f(A)$: $t_U(f(A))$ and $f(t_U(A))$. We establish basic properties of $t_U(f(A))$) and $f(t_U(A))$ for different functions of matrices. Some numerical tests demonstrate that the proposed preconditioners are very efficient for solving the system $f(A)x=b$. 相似文献
A novel well‐defined amphiphilic block copolymer, with the polyhedral oligomeric silsesquioxane (POSS) moiety at the junction of the two blocks of polystyrene and poly(ethylene oxide) (PEO), was designed and synthesized. First, a macroinitiator containing a POSS moiety and a PEO chain was prepared and then atom transfer radical polymerization of styrene was carried out in the presence of the macroinitiator in bulk. The polymerization results show that the process bears the characteristics of controlled/living free radical polymerizations. The structure and molecular weight of the polymers were characterized by GPC, 1H NMR, and FT‐IR spectroscopy. The self‐assembly behaviors of the polymers was investigated by TEM and SEM. It was observed that the polymers can self‐assemble into vesicles in aqueous solution.
Synchrotron radiation ultraviolet photoemission spectroscopy (SRUPS) and X-ray photoelectron spectroscopy (XPS) have been applied to investigate oxygen adsorption on a cadmium zinc telluride (CZT) (1 1 1)A surface. The surface chemical composition and the surface oxidation process were monitored by recording the Te 3d, O 1s, Zn 2p, Cd 4d core level peaks, and the Cd MNN Auger peak. The CZT (1 1 1)A surface was effectively oxidized by dosing oxygen directly. The typical surface state of the clean CZT (1 1 1)A surface was identified. After oxygen exposure, this surface state disappeared and a signal due to the formation of O–CZT appeared. In addition, the work function of CZT decreased with the increasing oxygen exposure. 相似文献
Different multicasting schemes in optical packet switched networks are discussed, including the parallel mode, serial mode, and hybrid mode multicasting schemes. Simulated modeling technique is applied to compare the network-level performance of the three multicasting schemes. A conclusion can be drawn from the results that since the hybrid-mode multicasting scheme can increase the multicast success ratio and reduce the packet retransmission times compared with the other two schemes, it is the best choice for delivering multicasting sessions in the optical packet switched networks. 相似文献
Using the principle of minimal energy and S-W model, the exchange bias for ferromagnetic/antiferromagnetic bilayers has been
investigated when the uniaxial anisotropy is misaligned with the exchange anisotropy. According to the relation between the
energy of the bilayer and the orientation of ferromagnetic magnetization, it is found that the bilayer will be in the monostable
state or bistable state when the external field is absent in the initial magnetization state. The monostable state or bistable
state of the bilayer, which determines the angular dependence of exchange bias directly, is controlled by the competition
between the exchange anisotropy and uniaxial anisotropy. When the applied field is parallel to the intrinsic easy axes and
intrinsic hard axes, one of the switching fields of the hysteresis loop shows an abrupt change, while the other keep continuous
by analyzing the magnetization reversal processes. Consequently, the exchange bias field and the coercivity will show a jump
phenomenon. The numerical calculations indicate that both the magnitude and direction of the exchange anisotropy will significantly
affect the angular dependence of exchange bias. The jump phenomenon of exchange bias is an intrinsic property of the bilayer,
which is dependent on the interfacial exchange-coupling constant, the orientation of the exchange anisotropy, the thickness
and uniaxial anisotropy constant of the ferromagnetic layer. 相似文献