精密干涉测量中余弦依赖算法的误差研究

针对相移算法中以双光束干涉为基础的余弦依赖算法的算法误差,以菲佐干涉仪精密测长为应用背景进行了研究。利用干涉光学的基本原理导出了在多束光干涉（经光学面多次反射、透射）的情况下干涉光强随相位分布的精确公式;通过数值分析得出了在给定参量条件下忽略次级反射光所引入的光强误差达到14．4％;对余弦依赖算法所引起的光强误差分别就四步算法、五步算法得出了不同的依赖关系：由于四步算法比五步算法对光强误差更为敏感,因而五步算法具有更高的准确度;对于两个反射面均具有较高反射率的情况,必须考虑算法误差;当测长准确度要求不太高时,在两个或至少其中一个反射面反射率较低的情况下可以忽略算法误差的影响。     

The effect of Cu–Zn distribution in zincian malachite on the formation of individual CuO and ZnO particles

Journal of Thermal Analysis and Calorimetry - Cu–Zn distribution in zincian malachite was regulated in preparation process, and its effect on the formation of CuO and ZnO during the thermal...     

Effect of heating rate on the sinterability,crystallization, and mechanical properties of sintered glass–ceramics from granite waste

Huge amounts of granite wastes have been generated in the granite-processing industry and should be properly disposed to reduce the negative impacts on the environment and health care. In this work, waste granite powder was modified and sintered to prepare high-strength and tough glass–ceramics. The heating rate was studied to clarify its effects on the sinterability, crystallization, and mechanical properties of glass–ceramics. With the increase in heating rate, the densification of sintered glass–ceramics was promoted by the liquid glassy phase from the microcline phase. The glass–ceramics were strengthened and toughened simultaneously due to the improved densification and increased crystallinity. The toughening mechanism was attributed to the crack bridging, deflection, and branching. The maximum flexural strength of 143 MPa and fracture toughness of 2.1 MPa m^1/2 were achieved with a heating rate of 50 °C min⁻¹, far superior to that of natural granite. The crystal structure of sintered glass–ceramics indicated the main crystalline phase of anorthite. These glass–ceramics with excellent mechanical properties promise the practical reutilization of granite wastes in the construction tiles.

     

Crystal‐State Photochromism and Dual‐Mode Mechanochromism of an Organic Molecule with Fluorescence,Room‐Temperature Phosphorescence,and Delayed Fluorescence

A D‐A‐D′ type pure organic molecule, named ODFRCZ, has unique triple‐emission character covering fluorescence, phosphorescence, and delayed fluorescence (DF). The phosphorescence of ODFRCZ has a rather long lifetime of about 350 ms at room temperature. One dimer of ODFRCZ with enhanced parallel molecular packing acts more effectively to prompt ISC processes, which further generates room‐temperature phosphorescence (RTP), owing to the larger transition dipole moment and closer energy level between S₁ and T_n. ODFRCZ is a rare example of an organic RTP molecule that shows dual‐stimuli responsiveness of dual‐mode mechanochromism (fluorescence red‐shift and RTP/DF on‐off switch) and reversible crystal‐state photochromism. This work may broaden the knowledge for stimuli‐responsive RTP organic molecules and lay the foundation for their wide‐scale applications.     

Copper(II)-catalyzed enantioselective conjugate addition of nitro esters to 2-enoyl-pyridine N-oxides

A highly enantioselective Michael addition of nitro esters to 2-enoyl-pyridine N-oxides was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields and with up to 96% ee.     

Alkaline degradation behavior of polyesteramide fibers: surface erosion

In this work, a new kind of aliphatic polyesteramide (PEA) copolymer based on -caprolactone and 6-aminocaproic acid was synthesized by the melt polycondensation method. Biodegradable PEA fibers were processed by the melt-spinning method. ¹H-NMR, FTIR, SEM, and tensile testing were used to characterize the degradation of PEA fibers in concentrated alkaline solution. The PEA fiber undergoes surface erosion in such concentrated alkaline solutions.     

A flexible sample introduction method for polymer microfluidic chips using a push/pull pressure pump

A push/pull sample introduction method based on push/pull pressure flow for microfluidic systems (cross, double T and multichannel structures) is presented. This leads to well-defined and controllable sample plugs even when dealing with long channels. By tuning the relative push/pull pressure, it is shown that the size of the sample plug can effectively be controlled. Good signal reproducibility upon continued sample introduction and subsequent chip electrophoresis employing fluorescence detection is demonstrated for different chip geometries (i.e. short channels and long channels). Since the performance of the method is relatively insensitive to chip geometry, it is particularly useful for polymeric prototype microchips as tedious optimization is not required. Furthermore, the push/pull sample introduction is extended to multichannel chips thus demonstrating the possibilities of applying the methodology for realizing single chip high throughput sample analysis.     

Change of the dominant luminescent mechanism with increasing current density in molecularly doped organic light-emitting devices

We have fabricated and measured a series of electroluminescent devices with the structure of ITO/TPD/Eu(TTA)₃phen (x):CBP/BCP/ALQ/LiF/Al, where x is the weight percentage of Eu(TTA)₃phen (from 0% to 6%). At very low current density, carrier trapping is the dominant luminescent mechanism and the 4% doped device shows the highest electroluminescence (EL) efficiency among all these devices. With increasing current density, Förster energy transfer participates in EL process. At the current density of 10.0 and 80.0 mA/cm², 2% and 3% doped devices show the highest EL efficiency, respectively. From analysis of the EL spectra and the EL efficiency-current density characteristics, we found that the EL efficiency is manipulated by Förster energy transfer efficiency at high current density. So we suggest that the dominant luminescent mechanism changes gradually from carrier trapping to Förster energy transfer with increasing current density. Moreover, the conversion of dominant EL mechanism was suspected to be partly responsible for the EL efficiency roll-off because of the lower EL quantum efficiency of Förster energy transfer compared with carrier trapping.     

On conformal measures for infinitely renormalizable quadratic polynomials

We study a conformal measure for an infinitely renormalizable quadratic poly- nomial.We prove that the conformal measure is ergodic if the polynomial is unbranched and has complex bounds.The main technique we use in the proof is the three-dimensional puzzle for an infinitely renormalizable quadratic polynomial.     

Reconfigurable directional couplers and junctions optically induced by nondiffracting Bessel beams

We put forward the concept of reconfigurable structures optically induced by mutually incoherent nondiffracting Bessel beams in Kerr-type nonlinear media. We address collinear couplers and X junctions and show how one can tune the switching properties of such structures by varying the intensity of the Bessel beams.