光子计数剪切干涉仪波前探测自适应光学系统噪声分析

在自适应光学系统中，波前探测器的噪声是主要误差源。针对我们建立的２．１６ｍ望远镜红外自适应光学系统，从伺服控制系统的角度分析了光子计数噪声及其在系统闭环过程中的传递，从理论上推导了系统的噪声功率谱、伺服传递函数以及开环和闭环噪声公式。另外，还给出了在系统中实测的开环和闭环噪声     

Experimental verification of combinational-deformable-mirror for phase correction

In adaptive optics (AO) system, the phase compensation capability is limited greatly by the actuator number of the deformable mirror (DM).     

Zinc oxide nanostructures: morphology derivation and evolution

Zinc oxide nanostructures of various types, including nanobelts, nanoplatelets, nanowires, and nanorods, have been synthesized via well-developed routes by many research groups. However, so far, the underlying mechanism for the morphology derivation and evolution of the nanostructures has not been elucidated in depth. In this article, we report the systematic investigation of the morphology evolution characteristics of ZnO nanostructures from dense rods to dense nanoplatelets, nanoplatelet flowers, dense nanobelt flowers, and nanowire flowers in an evaporation-physical transport-condensation approach. Through the use of crystal growth theory, the determining factors for the formation of different nanostructural morphologies were found to be gas-phase supersaturation and the surface energy of the growing surface planes. Other experimental parameters such as the temperature at the source and the substrate, the temperature difference and the distance between the source and the substrate, the heating rate of the furnace, the gas flow rate, the ceramic tube diameter, and the starting material are all correlated with supersaturation and impose an effect on the morphology evolution. This finding may have an important impact on the qualitative understanding of the morphology evolution of nanostructures and the achieving of desired nanostructures controllably.     

Homogeneous-to-Heterogeneous-Strategy Enables Multifunctional Phase-Change Materials for Energy Storage

Functional phase-change materials (PCMs) are conspicuously absent in various organic or inorganic solids with diversified applications in which the attributes of these molecular materials have been highly realized. Leakage problem during the phase transition process is the main obstacle on the way of widely use of solid-liquid PCMs who has been recognized to be promisingly practical candidates for energy storage owing to the high energy storage density and small volume change in the phase transition process. Herein, a novel homogeneous-to-heterogeneous-strategy, in which all the starting materials involved display a homogeneous state and the encapsulation framework formed in situ in the encapsulation process, enabled by an aerogel reaction of silica was realized under the catalysis of an organic base. Besides the comprehensive study upon energy storage performance, light-to-thermal conversion and recyclability performance study of the obtained materials reveal the clear superiority over pristine paraffin wax (PW) thanks to the versatility and robustness of this fabrication method. More importantly, the homogeneous-to-heterogeneous-strategy endows a unique adsorption ability with respect to organic pollutant due to the PCMs inside and therefore bearing a great potential to be used in environment protection fields.     

Redox-Induced Structural Change in Artificial Heterometallic-Oxide Cluster Mimicking the Photosynthetic Oxygen-Evolving Center

The oxygen-evolving center (OEC) in photosynthesis is a unique Mn₄CaO₅-cluster that catalyzes the water-splitting reaction in nature. Understanding its catalytic mechanism for the O=O bond formation is of great challenge and long-standing issue, which is severely restricted by the lack of precise structure and mechanism mimics of this heterometallic-oxide cluster. Herein, we report two synthetic (Mn₃XO₄)₂O-clusters (X=Sr²⁺, La³⁺) that closely mimic the heterometallic-oxide Mn₃XO₄ cubane and three different types of μ-oxide bridges (μ₂-O²⁻, μ₃-O²⁻, and μ₄-O²⁻) simultaneously as seen in the OEC. By resolving the crystal structures of both oxidized and reduced forms of the cluster, we have identified significant redox-induced structural changes that take place on the μ₂-oxide bridge, rather than the μ₄-oxide or μ₃-oxide bridges. Our results provide chemical insights into understanding the reactivity of three different types of oxide bridges in the biological Mn₄CaO₅-cluster in PSII.     

Development and validation of a forensic multiplex InDel assay: The AGCU InDel 60 kit

Marker sets based on insertion/deletion polymorphisms (InDels) combine the characteristics of both short tandem repeats (STRs) and single nucleotide polymorphisms and have served as effective complementary or stand-alone systems for human identification in forensics. We developed a novel multiplex amplification detection system, designated the AGCU InDel 60 kit, containing 57 autosomal InDels, 2 Y-chromosomal InDels, and the amelogenin locus and validated the kit in a series of studies, which included tests of the PCR conditions; tests for sensitivity, species specificity, reproducibility, stability, and mock case samples; degradation studies; and a population study. The results indicated that the AGCU InDel 60 kit was accurate, specific, reproducible, stable, and robust. Complete DNA profiles were obtained even with 125 pg of human DNA. In tests of artificially degraded samples, we found that the number of alleles detected by the validated kit was considerably greater than that detected by the STR-based AGCU 21+1 kit, even as the degree of degradation increased. Additionally, 564 unrelated individuals from three Han groups were investigated using this novel system, and the values of combined power of discrimination and combined power of exclusion were not less than 1–4.9026 × 10⁻²⁴ and 1–3.1123 × 10⁻⁵, respectively. Thus, the results indicated that the novel kit was more powerful than the previous version of the InDel kit (the AGCU InDel 50 kit). Our results suggest that the AGCU InDel 60 kit can serve as an efficient tool for human forensics and a supplementary kit for population genetics research.     

Experimental validation of closed-loop adaptive optics based on a self-referencing interferometer wavefront sensor and a liquid-crystal spatial light modulator

A closed-loop adaptive optics system based on a self-referencing interferometer wavefront sensor (SRI WFS) using phase-shifting point-diffraction technique and an electrically addressed phase-only liquid-crystal spatial light modulator (LC SLM) is built and validated experimentally. The wavefront aberration of incoming beam is directly measured by analyzing four frames phase-shifted interferograms captured by a single CCD camera in two camera shots, and then by loading the conjugate function onto the SLM the wavefront aberration is corrected. The proposed scheme does not rely on any complicated control algorithm or wavefront-reconstruction algorithm and can achieve high-resolution and high-accuracy correction. Closed-loop correction results of single order Zernike aberrations and a Kolmogorov turbulence phase screen show that considerable improvements in the Strehl ratio (of greater than 0.94) is achieved.     

Thickness-dependent photocatalytic performance of ZnO nanoplatelets

In this paper, we report the large-scale synthesis of ZnO nanoplatelets as thin as 10 nm. The nanoplatelets show higher efficiency in photodegrading organic dyes than ZnO nanorods do, and for the nanoplatelets, the thinner they are, the higher the performance. The photocatalytic decomposition of organic dyes (eosin B) by ZnO nanoplatelets compares favorably to the performances of ZnS porous nanoparticles and commercial Degussa P25 titania particles. This finding may have significant implications in the environment remediation and the fabrication of functional nanodevices.