Matrix effect suppressing in the element analysis of soils by laser-induced breakdown spectroscopy with acoustic correction

Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppressing was developed using laser-induced plasma acoustic signals to correct the original spectrum,thereby improving the analysis accuracy of the soil elements.A good linear relationship was investigated firstly between the original spectral intensity and the acoustic signals.The relative standard deviations(RSDs)of Mg,Ca,Sr,and Ba elements were then calculated for both the original spectrum and the spectrum with the acoustic correction,and the RSDs were significantly reduced with the acoustic correction.Finally,calibration curves of MgⅠ285.213 nm,CaⅠ422.673 nm,SrⅠ460.733 nm and BaⅡ455.403 nm were established to assess the analytical performance of the proposed acoustic correction method.The values of the determination coefficient(R~2)of the calibration curves for Mg,Ca,Sr,and Ba elements,corrected by the acoustic amplitude,are improved from 0.9845,0.9588,0.6165,and 0.6490 to 0.9876,0.9677,0.8768,and 0.8209,respectively.The values of R~2 of the calibration curves corrected by the acoustic energy are further improved to 0.9917,0.9827,0.8835,and 0.8694,respectively.These results suggest that the matrix effect of LIBS on soils can be clearly improved by using acoustic correction,and acoustic energy correction works more efficiently than acoustic amplitude correction.This work provides a simple and efficient method for correcting matrix effects in the element analysis of soils by acoustic signals.

Generation of Optical Vortex Using a Spiral Phase Plate Fabricated in Quartz by Direct Laser Writing and Inductively Coupled Plasma Etching

A simple, economical and reliable technique is proposed for fabricating a spiral phase plate （SPP） in a quartz substrate to generate optical vortex with a unit topological charge at the wavelengths of 632.8nm. The spiral phase plate is first formed in the photoresist by direct laser writing lithography and then transferred into the quartz substrate by inductively coupled plasma etching. The performance of the fabricated SPP is verified by using beam intensity distribution, which is in agreement with the theoretical calculation result. The interference measurement suggests that we have succeeded to generate optical vortex with a unit topological charge with the fabricated SPP.

The study of a new n/p tunnel recombination junction and its application in a-Si:H/μc-Si:H tandem solar cells

This paper reports that a double N layer （a-Si：H/μc-Si：H） is used to substitute the single microcrystalline silicon n layer （n-μc-Si：H） in n/p tunnel recombination junction between subcells in a-Si：H/μc-Si：H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si：H/μc-Si：H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.

Location algorithm for seal imprints on Chinese bank-checks based on region growing

The paper focuses on location of seal imprints on Chinese bank-checks based on region growing.Region growing method can be applied to searching and locating connection region in an image.A seal imprint,however,is generally composed of various connection regions which are unconnected to each other.In order to locate the seal imprint,these connection regions must be fused together.In the paper,an algorithm for locating seal imprints on Chinese bankchecks based on region growing is proposed, of which a fusion criterion for connection regions in a seal imprint is put forth based on the image feature of Chinese bankcheck,and a center-rays model is proposed to find the topological relationship between connection regions,for which externally-tangent rectangle of region is used as the mark of location of region.The location experiment is achieved with a false-acceptance rate of 7.1% and a false-rejection rate of 0% on Chinese bankcheck.

Properties of Fraunhofer Diffraction by an Annular Spiral Phase Plate for Sidelobe Suppression

A simple and accurate method for calculating the optimal width of an annular spiral phase plate （SPP） to generate optical vortices with sidelobe suppression is proposed. The sideloSes can he sharply suppressed when the ratio of inner and outer radii of an annular SPP is equal to that of the principal ring and the first sidelobe diffracted by a circular SPP with the same topological charge n. Moreover, the ratio of the inner and outer radii of the optimal annular SPP depends only on the topological charge n and is not affected by the incident wavelength or the size of the SPP.

OLED-on-silicon chip with new pixel circuit

A low power 640×480 OLED-on-silicon chip design that used in microdisplay was presented.A novel pixel circuit was proposed to meet the special requirement of OLED-on-silicon.The novel pixel consists of three transistors and one capacitor(3T1C).It has simple structure and can effectively reduce the current glitch generated during the AC driving from 55 μA to 7.5 μA,so that it can improve the precision of grayscale of display as well as extend the lifetime of OLED material.Except for the pixel array,low power row driver,column driver and other functional modules were also integrated on the chip.Several techniques were adopted to reduce the power consumption and frequency requirement of the chip,Finally,a 16×3×12 resolution chip was fabricated with standard 0.35 μm CMOS process of CSM and the chip can operate correctly.

A study of ultrafast electron diffusion kinetics in ultrashort-pulse laser ablation of metals

Temperature dependence of the electron diffusion in metallic targets, where the electron-lectron collision is the dominant process, is investigated with the help of an extended two-temperature model. In sharp contrast to the low electron temperature case, where only the electron-phonon collisions are commonly considered, the electron diffusion process underlying the high electron temperatures evolves dramatically different in both temporal and spatial domains. Calculated results of the ablation yield at different pulse durations are presented for a copper plate impinged by ultrashort laser pulses with energy fluences ranging from 0.1 J/cm^2 to 10 J/cm^2. The excellent agreement between the simulation results and the experimental data indicates the significant role of electron-electron collisions in material ablations using intense ultrashort laser pulses.

Time-resolved shadowgraphs and morphology analyses of aluminum ablation with multiple femtosecond laser pulses

Aluminum ablation by multiple femtosecond laser pulses is investigated via time-resolved shadowgraphs and scanning electron microscope （SEM） images of the ablation spot. The spatial distribution of the ejected material and the radius of the shock wave generated during the ablation are found to vary with the increase in the number of pulses. In the initial two pulses, nearly concentric and semicircular stripes within the shock wave front are observed, unlike in subsequent pulses. Ablation by multiple femtosecond pulses exhibits different characteristics compared with the case induced by single femtosecond pulse because of the changes to the aluminum target surface induced by the preceding pulses.

Examination of Validity of Paraxial Approximation in Second Harmonic Generation Microscopy under Low Numerical Aperture

由使用一条 vectorial 途径，同等的有效性在第二泛音代(SHG ) 的轴的近似当样品是骨胶原时，在低数字孔(NA ) 下面的显微镜学被检验。bril。由于 dzzx 的更大的价值和 SHG 的 tensorial 自然，部件 Ez 集中。高龄可以有强壮的 e。SHG 的放射模式上的 ect。当 NA 的价值超过 0.3 时，数字结果显示那， e。Ez 的 ect 不能被忽视，它导致同等的无效在 SHG 显微镜学的轴的近似尽管 SHG 显微镜学仍然在低 NA 集中下面。

Bragg Gratings Written in Photonic Crystal Fibres with a High-Index Germanosilicate Core

布拉格栅栏正直地借助于 193nm ArF 前 cimer 激光与一个高度做 Ge3+ 的核心被写进 10 戒指 photonic 水晶纤维(PCF ) 。栅栏铭文效率被改进，由于在基本模式和感光性的核心之间的提高的光敏度和大重叠。暴露持续时间仅仅持续不到 180 s。另外，高索引的核心改变 PCF 和模式回声剧降因此被获得的二组更高的顺序的形式的性质。强壮的 cladding 模式回声被观察，因为象 LP02 一样模式与基本模式有大重叠积分。

Fibre Bragg Gratings Inscribed in Homemade Microstructured Fibres

纤维布拉格栅栏(FBG ) 被标准阶段面具方法在自做的 microstructured 纤维刻写。在向前基本的模式和向后的 cladding 模式之间的提高的政变石楠被获得。联合的模式并且光谱特征 reinvestigated 试验性地。cladding 模式回声能被充满活跃材料进空气洞影响，它将为在光纤通讯和察觉到的系统的悦耳的 photonicdevices 的实现是有用的。

Highly Stable CdSe/CdS/ZnS Fluorophores in Acidic Environment:Acile Preparation and Modification of Core/shell/shell Nanocrystals

We described a facile method for preparing CdSe/CdS/ZnS core/shell/shell nanocrystals from air-stable single source precursors.The single source precursors of cadmium ethylxanthate and zinc ethylxanthate were used to form CdS and ZnS shell layers in octadecene.An efficient modification of CdSe/CdS/ZnS nanocrystals was subsequently performed to obtain hydrophilic nanocrystal fluorophores with good stability in a pH range of 1.6—10.

Terahertz Metamaterial Sensor Based on Electromagnetically Induced Transparency Effect

A terahertz metamaterial sensor adopting the metamaterial-based electromagnetically induced transparency（EIT） effect is presented for determining the 1,4-dioxane concentration in its aqueous solution. The metamaterial sensor, which consists of an EIT element unit with a cut-wire metallic resonator and two split-ring metallic resonators fabricated on a 490-μm thick silicon substrate, operates in a transmission geometry. The EIT peak was red-shifted and decreased with the increase of the water volume. A maximum redshift about 54 GHz of the EIT peak was detected between the 1,4-dioxane and water. The presented linear behavior and high sensitivity of the EIT peak depending on the water concentration pave a novel avenue for sensor applications.

Fabrication of Long-Period Fibre Gratings Using 800 nm Femtosecond Laser Pulses

Long-period fibre gratings inside standard single-mode optical communication fibres are successfully fabricated with infrared femtosecond laser pulses. The refractive index perturbations are well confined within the fibre core by choosing the proper laser focusing parameters and translation speed of the fibre during the direct laser writing process. With the self-focusing effect considered and at a constant average irradiation dose of 1.62 × 10^3 J/（cm^2μm）, the threshold intensity for fabricating long-period gratings with infrared femtosecond laser pulses is determined to be 5.13 × 10^13 W/cm2.

Characteristics and New Measurement Method of NCSFs of Individual Color Mechanisms of Human Vision

We propose a new method for determining neural contrast sensitivity functions （NCSFs） of isolated color mechanisms based on the measurements of wave-front aberrations and isoluminant color contrast sensitivity functions （CSFs）. Compared with the traditional method, this technique avoids the coherent noise and speckle noise, which are brought by the interference of laser beams, and has great flexibility for the measurements of NCSF of different color mechanisms. Our experiments indicate that the mean NCSF and CSF of the red mechanism are higher than those of the green mechanism, respectively, while those of the blue mechanism are the lowest. However the relative heights of the peak of NCSF and CSF between red and green mechanisms vary in subjects. There are some individuals whose peak values of NCSF and/or CSF of green mechanism are higher than that of the red mechanism. The NCSFs and CSFs of isolated color mechanisms all exhibit the similar characteristics and variation tendency. With the statistical average, the NCSFs of the red, green and blue mechanisms are higher than the corresponding CSFs in the whole spatial frequency. Compared with the corresponding CSFs curves, the peaks of the NCSFs of isolated color mechanisms shift toward higher spatial frequencies, especially for that of blue mechanism which has a largest shift of 3.9 c/deg.

Analysis of second-harmonic generation microscopy under refractive index mismatch

On the basis of the vector diffraction theory and Green＇s function method, this paper investigates the effects of refractive index mismatch on second-harmonic generation （SHG） microscopy. The polarization distribution and SHG intensity are calculated as functions of the sample radius and probe depth. The numerical results show that refractive index mismatch can result in peak intensity degradation, increase secondary lobes and extension of second- harmonic polarization distribution. Because of the attenuation of polarization intensity, the detected SHG intensity significantly decreases with increasing probe depth, which can limit the imaging depth of SHG microscopy inside thick samples. Forward SHG intensity decays slowly than backward SHG, due to the combination of extension second-harmonic polarization distribution and strong dependency of forward SHG on sample radius.

Reduction of the phosphorus contamination for plasma deposition of p-i-n microcrystalline silicon solar cells in a single chamber

This paper investigates several pretreatment techniques used to reduce the phosphorus contamination between solar cells. They include hydrogen plasma pretreatment, deposition of a p-type doped layer, i-a-Si：H or μc-Si：H covering layer between solar cells. Their effectiveness for the pretreatment is evaluated by means of phosphorus concentration in films, the dark conductivity of p-layer properties and cell performance.

Effects of annealing rate and morphology of sol–gel derived ZnO on the performance of inverted polymer solar cells

The effects of annealing rate and morphology of sol–gel derived zinc oxide （ZnO） thin films on the performance of inverted polymer solar cells （IPSCs） are investigated. ZnO films with different morphologies are prepared at different annealing rates and used as the electron transport layers in IPSCs. The undulating morphologies of ZnO films fabricated at annealing rates of 10 ℃/min and 3 ℃/min each possess a rougher surface than that of the ZnO film fabricated at a fast annealing rate of 50 ℃/min. The ZnO films are characterized by atomic force microscopy （AFM）, optical transmittance measurements, and simulation. The results indicate that the ZnO film formed at 3 ℃/min possesses a good-quality contact area with the active layer. Combined with a moderate light-scattering, the resulting device shows a 16% improvement in power conversion efficiency compared with that of the rapidly annealed ZnO film device.

In-situ growth of Ca/P salt on Ti surface induced by femtosecond lasers in hydroxyapatite suspension

Pure Ti plate surfaces are micro-ablated by femtosecond lasers in the ambience of hydroxyapatite suspension. It is found that three-stage hierarchical surface structures are produced with various laser energies. When the laser energy is 150μJ, a lava-like structure with a distribution of nanoholes is dispersed evenly on the laser ablated surface. While in the case of 300 μJ, the grooves-and-islands micro-patterns covered with nanoparticles are generated on the surface. Remarkably, Ca/P based substances are revealed to firmly deposit on the micro-structured surfaces. More phosphate growth is seen for the higher laser energy. Discussions suggest that the additional elements deposition could be attributed to the chemical reaction of plasma related ions in the suspension and their subsequent crystallisation on the fresh surfaces of Ti plate due to the femtosecond laser ablation.

Influence of local environment on the intensity of the localized surface plasmon polariton of Ag nanoparticles

A combined Ag nanoparticle with an insulating or conductive layer structure has been designed tor molecular detection using surface enhanced Raman scattering microscopy. Optical absorption studies revealed localized surface plasmon resonance, which shows regular red shift with increasing environmental dielectric constant. With the combined structure of surface enhanced Raman scattering substrates and rhodamine 6C as a test molecule, the results in this paper show that the absorption has a linear relationship with the local electromagnetic field for insulating substrates, and the electrical property of the substrate has a non-negligible effect on the intensity of the local electromagnetic field and hence the Raman enhancement.