Design of a compact off-axis freeform three-mirror system in a circular configuration.

A compact off-axis three-mirror system, especially with a wide field of view and small f-number, continues to present challenges in the optical design field. To design a compact off-axis three-mirror system based on a freeform surface, an optimization method with a circular configuration and four parameters is proposed. In the proposed method, the f-number and angles of mirrors are combined to optimize and achieve high-quality imaging, which means the modulation transfer function is close to the diffraction limit. To evaluate the performance of the proposed method, four design examples with different fields of view (4∘×4∘, 6∘×6∘) and f-numbers (2, 1.75) were created. The results showed that the compact off-axis three-mirror system based on a freeform surface can be designed with a wide field of view, small f-number, and high-quality imaging using the proposed method. Unlike other design methods, the surface parameters of mirrors are obtained with only one calculation and are close to the final optimization results, which saves both time and resources for optimization. The findings indicate that the method is accurate and effective for designing compact off-axis three-mirror systems with freeform surfaces.

Structure, magnetic properties and spin density of two alternative Mn(II) coordination polymers based on 1,4-bis(2'-carboxyphenoxy)benzene.

Two novel manganese coordination polymers [Mn2(µ2-bcpb)(µ4-bcpb)(2,2'-bipy)2]n (1) and [Mn2(µ3-bcpb)2(2,2'-bipy)2(H2O)]n (2) (H2bcpb = 1,4-bis(2'-carboxylato phenoxy)-benzene; 2,2'-bipy = 2,2'-bipyridine), have been synthesized successfully from the same reactants. This unusual selectivity was corroborated by X-ray powder diffraction. Single crystal X-ray diffraction analysis of complex 1 reveals that neighboring Mn(II) ions are linked via two bcpb2- anions to form a dinuclear Mn(II) subunit [Mn2(µ1,1-COO)2]2+ with a Mn⋯Mn distance of 3.3758 (6) Å. And π⋯π interactions between aromatic rings of the bcpb2- and 2,2'-bipy ligands stabilize the two-dimensional extended coordination network with the unprecedented Schläfli symbols {4·62}2{42·62·82}. In the [Mn2(µ1,3-COO)2]2+ subunit of 2, two linking bcpb2- ligands subtend an interaction distance of 4.4048(6) Å. Intermolecular O-H⋯O hydrogen bonds involving oxygen atoms of carboxylic acid and coordinated water molecules connect adjacent 1D chain molecules into a 2D network. Experimental temperature-dependent magnetic susceptibility measurements and spin density analyses by DFT disclose that compounds 1 and 2 display different magnetic properties.

Cooled infrared off-axis freeform three-mirror system design with convenience in testing and assembly.

A cooled infrared off-axis freeform three-mirror system, especially with a small f-number and 100% cold stop efficiency, continues to present challenges in design, testing, and assembly. A primary mirror and tertiary mirror integrated structural model is proposed to design a cooled infrared off-axis three-mirror system that is convenient to test and assemble. In the proposed model, the f-number is used to calculate the parameters of the mirrors, and a freeform surface is adopted to achieve high imaging quality, which means the spot diagram radius (RMS) is smaller than the Airy radius. To evaluate the performance of the proposed method, two design examples with different f-numbers (2, 1.4) were constructed. The results showed that the cooled infrared off-axis three-mirror system can be designed with a small f-number, 100% cold stop efficiency, and high convenience in testing and assembly.

[Polymorphisms within the interferon-Gamma receptor associated with systemic lupus erythematosus].

OBJECTIVE: To assess the association between polymorphisms within the interferon-Gamma receptor gene(IFN-GammaR) and systemic lupus erythematosus (SLE) in Chinese people. METHODS: The IFN-GammaR genotypes of 94 SLE patients and 80 healthy subjects were examined by the reverse transcription-polymerase chain reaction (RT-PCR)-single-strand conformation polymorphism (SSCP) method, RT-PCR-restriction fragment length polymorphism (RFLP) method and DNA sequencing. RESULTS: There was no statistically significant difference in the IFN-GammaR genotype frequencies between the two groups. The IFN-Gamma R2 Arg64/Arg64 genotype decreased the risk of SLE (OR = 2.481, 95% CI 0.992 - 6.203, P = 0.047). The decreased risk of the development of SLE was detected in the individuals who had the combination of IFN-GammaR2 Arg64/Arg64 genotype and IFN-GammaR1 Val14/Val14 genotype (OR = 2.481, 95% CI 0.992 - 6.203, P = 0.047). CONCLUSION: The IFN-GammaR2 Arg64/Arg64 genotype does not determine susceptibility to SLE in Chinese people, and the combination of IFN-Gamma R2 Arg64/Arg64 genotype and IFN-Gamma R1 Val14/Val14 genotype does not, either.