Diode-pumped actively Q-switched Tm:YAG ring laser operation at room temperature

2-μm lasers with high pulse energy and long pulse width of hundreds of nanoseconds are needed urgently in the accurate wind velocity lidar systems. This paper presents the acoustic-optical Q-switched Tm:YAG laser performance in a pulsed-laser-diode end-pumping figure-eight ring resonator structure. Pulse energy and pulse width are investigated with the increasing of the incident pump energy at different repetition rate operation. Maximum energy of 4.6 mJ with the pulse width of 179.2 ns and 3.57 mJ with pulse width of 184.4 ns are obtained at the repetition rate of 20 and 100 Hz, respectively. Under free-running and Q-switched operation, the peak output wavelength is 2.014 μm at all time, and the beam quality factors are lower than 2 times diffraction-limited measured by a knife-edge traveling method.     

Localized Chemical Remodeling for Live Cell Imaging of Protein-Specific Glycoform

Live cell imaging of protein-specific glycoforms is important for the elucidation of glycosylation mechanisms and identification of disease states. The currently used metabolic oligosaccharide engineering (MOE) technology permits routinely global chemical remodeling (GCM) for carbohydrate site of interest, but can exert unnecessary whole-cell scale perturbation and generate unpredictable metabolic efficiency issue. A localized chemical remodeling (LCM) strategy for efficient and reliable access to protein-specific glycoform information is reported. The proof-of-concept protocol developed for MUC1-specific terminal galactose/N-acetylgalactosamine (Gal/GalNAc) combines affinity binding, off-on switchable catalytic activity, and proximity catalysis to create a reactive handle for bioorthogonal labeling and imaging. Noteworthy assay features associated with LCM as compared with MOE include minimum target cell perturbation, short reaction timeframe, effectiveness as a molecular ruler, and quantitative analysis capability.     

Formation of Hybrid Perovskite Tin Iodide Single Crystals by Top‐Seeded Solution Growth

Hybrid perovskites have generated a great deal of interest because of their potential in photovoltaic applications. However, the toxicity of lead means that there is interest in finding a nontoxic substitute. Bulk single crystals of both cubic CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃ were obtained by using the top‐seeded solution growth method under an ambient atmosphere. Structural refinement, band gap, thermal properties, and XPS measurements of CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃ single crystals are also reported in detail. These results should pave the way for further applications of CH₃NH₃SnI₃ and CH(NH₂)₂SnI₃.     

Cation-π Interactions. Synthesis and Crystal Structure of Palladium Complex: [K(DB18C6)]2[Pd(SCN)4]

A novel Pd(II)-dibenzo-18-crown-6 (DB18C6) complex [K(DB18C6)]2[Pd(SCN)4] has been isolated and characterized by X-ray diffraction analysis. In the solid state, it displays a quasi-one-dimensional infinite chain of two [K(DB18C6)] + complex cations and a [Pd(SCN)4]2- anion bridged by K+-p interactions between adjacent [K(DB18C6)] + units.     

An Adaptive Fast Multipole Higher Order Boundary Element Method for Power Frequency Electric Field of Substation

An adaptive fast multipole higher order boundary element method combining fast multipole （FM） with a higher order boundary element method is studied to solve the power frequency electric field （PFEF） of substations. In this new technique, the iterative equation solver GMRES is used in the FM, where matrix-vector multiplications are calculated using fast multipole expansions. The coefficients in the preconditioner for GMRES are stored and are used repeatedly in the direct evaluations of the near-field contributions. Then a 500kV outdoor substation is modeled and the PFEF of the substation is analyzed by the novel algorithm and other conventional methods. The results show that, in computational cost and the storages capability aspects, the algorithm proposed in this study has obvious advantages. It is suitable for the calculation of the large-scale PFEF in complex substations and the design of electromagnetic compatibility.     

Diode-pumped single longitudinal mode lasing of Tm,Ho:YLF microchip laser

Short resonant cavity which owns broad free spectral range is useful to select single-frequency. We take Tm,Ho:YLF (Tm 6%; Ho 0.4%) microchip pumped by diode laser to attain high efficiency single-longitudinal-mode laser. Both end faces are coated. The microchip is the oscillate cavity itself. It’s placed in the Dewar flask, which is filled with liquid nitrogen to keep the temperature at 77 K. Comparison of the laser characteristics between a 0.9 mm microchip and a 0.5 mm microchip were expressed in this report. The maximum single-longitudinal-mode power are 33 and 76 mW, corresponding the slope efficiency of both lasers are 12 and 37%, separately. The beam quality is about 1.06 and 6.8 for 0.9 mm microchip and 0.5 mm microchip, measured by the knife-edge method.     

The Application of Complex Wavelet Transform to Spectral Signals Background Deduction

The accuracy of spectrograms may be affected by baseline excursion or drift when infrared spectrometers are used in the analyses of gases. Background deduction or baseline correction is one of the effective pretreatment methods that can improve measurement accuracy. This paper presents a novel methodology based on complex wavelet transform algorithm to perform background deduction. The complex wavelet transform methodology establishes a complex wavelet filter to decompose the spectral signals first, and set the decomposition coefficients in the high-frequency section to zero, and then reconstruct the background signals; finally, the background deduction can be realized by deducting the background signals. In this study, the complex wavelet established by Daubechies was selected to demonstrate background deduction aiming at simulative spectral signals with different backgrounds and the real spectral signal of SF6 decomposition gases. Compared with the results done by the real wavelet transform in the same conditions, the results indicate that complex wavelet transform methodology can perform background deduction more efficiently than real wavelet transform methodology, thus improving the effectiveness and precision of spectrogram measurements greatly, which is useful for SF6 gas decomposition compositions analysis

     

一种衍射测量条纹的方法

介绍一种基于Labview的虚拟仪器开发平台，采用美国国家仪器公司的PCI-6221数据采集卡对单缝衍射光强分布的数据采集和测量的方法。测量结果理论值基本吻合，说明运用Labview的测量方案切实可行。     

四模Lorenz系统的动力学行为及其数值模拟

<正>1引言美国气象学家E.N.Lorenz在1963年提出的用来刻画热对流不稳定性的模型,即Lorenz混沌模型,后来人们对这个系统进行了大量而深入的研究.到目前为止,Lorenz系统的动力学行为已经比较清楚.1998年,Mischaikow和Mrozek用Conley指标理论和严格的计算机辅助计算方法证明了Lorenz系统存在混沌行为.1999年,Tucker则用规范型理     

Numerical simulation of nanoparticle pattern fabricated by electrostatic spray deposition

Electrospray deposition(ESD) as a patterning method of nanoparticles deposited on a substrate has attracted much attention due to several advantages over other methods.However,obtaining an optimum ESD processing condition for nanoparticle pattern relies much on trial experiments because of the lack of reliable numerical simulation.In this study,the deposition characteristics of nanoparticle generated by electrospray were investigated by using a three-dimensional Lagrangian model.Three important process parameters,including solution dielectric constant,applied voltage and surface charge density on mask were considered by fixing the geometrical parameters of the ESD device.Simulation result showed that under the condition of without a mask,the spray diameter increases with increasing solvent dielectric constant,and higher applied voltage makes the spray area wider.Controllability of focusing by changing surface charge density on the mask was confirmed:higher surface charge density on the mask results in more focused deposition.Validity of the numerical simulation developed in this study was verified by comparison with experimental data.