万工显干涉测量衍射器

万能测量显微镜是机械制造行业中广泛应用的精密测试仪器。但它常用的普通下透射照明方法,由于光线绕射等因素的影响,误差很大。所谓理想光圈,也因每台仪器结构和制造上的差异。

Improved Algorithm of Pattern Classification and Recognition Applied in a Coal Dust Sensor

To resolve the conflicting requirements of measurement precision and real-time performance speed,an im-proved algorithm for pattern classification and recognition was developed. The angular distribution of diffracted light varies with particle size. These patterns could be classified into groups with an innovative classification based upon ref-erence dust samples. After such classification patterns could be recognized easily and rapidly by minimizing the vari-ance between the reference pattern and dust sample eigenvectors. Simulation showed that the maximum recognition speed improves 20 fold. This enables the use of a single-chip,real-time inversion algorithm. An increased number of reference patterns reduced the errors in total and respiring coal dust measurements. Experiments in coal mine testify that the accuracy of sensor achieves 95%. Results indicate the improved algorithm enhances the precision and real-time ca-pability of the coal dust sensor effectively.

Diffraction Properties of Blazed Gratings Illuminated with Broad-bandwidth and Divergent Beam

Far-field intensity and diffraction efficiency of the blazed reflection gratings illuminated with broad-bandwidth and divergent beam are investigated.When the spectral width and divergence of the incident beam with a constant energy increase,the maximum intensity decreases,and the half width at e-2 of the maximum intensity becomes wider.Diffraction efficiency has no deterioration for the blazed grating with a proper groove shape even when the incident light contains a broad range of wavelengths and comes from a wide range of angles.

Growth of Hierarchically Structured High-Surface Area Alumina on FeCralloy~ Rods

The formation of metastable alumina phases due to the oxidation of commercial FeCralloy（R） rods （0.5 mm thickness） at various temperatures and time periods has been examined. This structured layer acts as an anchor to bind additional coatings of alumina via wash-coat techniques, thereby improving the layer thickness and increasing adhesion of the catalytic surface. Optimisation of the layer thickness and catalytic properties were conducted, using a range of analytical systems [scanning electron microscope （SEM）, energy dispersive X-ray （EDX） and X-ray diffraction （XRD）]. The modified FeCralloy（R） rods were tested in a fixed bed reactor rig to assess the impact on yield for the dehydrogenation of methylcyclohexane.

Photoluminescence and X-ray Diffraction of Distributed Bragg Reflector

Spectral and structural characteristics of distributed Bragg reflector (DBR) in vertical-cavity surface-emitting lasers were studied with photoluminescence and double-crystal X-ray diffraction measurement.The expected high quality epitaxial DBR structure was verified.In the X-ray double-crystal rocking curves of DBR the zeroth-order peak,the first and second order satellite peaks were measured.Splitting of diffraction peak appeared in the rocking curves was analyzed.The effects of introduced deep energy levels on the structural perfection and optical properties were discussed.

Free electron laser based on the Smith-Purcell radiation

A Smith-Purcell （SP） free electron laser （FEL） ,composed of a metallic diffraction flat grating,an open cylindrical mirror cavity and a relativistic sheet electron beam with moderate energy, is presented. The characteristics of this device are studied by theoretical analysis,experimental measurements and particle-in-cell （PIO） simulation method. Results indicate that the coherent radiation with an output peak power up to 50 MW at millimeter wavelengths can be generated by using relativistic electron beam of moderate energy.

Oxidative Desulfurization over Molybdenum-containing MCM-41

Two series of molybdenum-containing MCM-41 catalysts were prepared for oxidative desulfurization ofdibenzothiophene （DBT） using t-butylhydroperoxide （TBHP） as the oxidant. The electronic properties, pore dimension and hydrophilic properties of the catalysts were studied by XRD, BET, and 1R spectrometry. The Mo-Al2O3 catalyst and TiMCM-3% were also studied for comparison. The two series of MCM-41 zeolite with MoO3 in the framework or impregnated on the surface exhibited considerable activities at low MoO3 content and both were faxbetter than the Mo-Al2O3 catalyst, but had lower activities as compared to the TiMCM-3% catalyst. The catalysts with the highest activity were evaluated in a fixed-bed reactor. The concentration of DBT in model diesel upon oxidative desulfurization was successfully reduced from 5000 ppm to less than 150 ppm, but the catalysts were deactivated very fast. The probable reason was the high affinity of DBTO2 to the MCM-41 skeleton, especially to MoO3. The catalysts could restore most of its original activity by treating with alcohol.

Cracking of Palm Oil over H-AIMCM-41 Catalyst

The objective of this research was to develop a catalyst for efficient cracking of palm oil to produce biogasoline. Mesoporous alumino-silicate, A1MCM-41, was synthesized by hydrothermal treatment to the mixture of sodium silicate, sodium aluminates, TMAOH （tetramethylammonium hydroxide）, and CTMAB （cetyltrimethylammonium bromide）, in Aquadest as a solvent. This process was carried out within 12 h of aging time at 100 ℃ in a teflon-lined stainless steel autoclave. The solid phase was filtered, then washed with distilled water, and dried in an oven at 80 ℃ for 24 h. The surfactant CTMAB was removed by calcination at 540 ℃ for 6 h using heating rate of 2 ℃/min. The as-synthesized and calcined powder was characterized by using FTIR （frontier transform infra red spectroscopy）, XRD （X-ray diffraction）, and TEM （transmission electron microscopy） methods. The product of AIMCM-41 was then converted into H-AIMCM-41 by ion exchanged in 0.5 M of NHaCI solution followed by filtration, drying at 80 ℃ for 24 h, and calcination at 540 ℃. The product of catalyst was used for catalytic conversion of PO （palm oil） to biogasoline in a fixed bed reactor at 200-400 ℃, under atmospheric pressure, and ratio of PO to catalyst was 200. The product of cracking was then distilled at 60 ℃ and analyzed using GC-MS （gas liquid chromatography - mass spectrometry） method. Result of the works shows that the catalyst had 4.49 nm of lattice parameter, and the cracking of PO gave 56.6% conversions with 29.4% selectivity to biogasoline like fraction.

A holographic three-slit interferometer

A new type of real-time holographic three-slit interferometer is presented. It uses a calcite polarized optical element to obtain objective light and reference light to record a hologram. Its remarkable feature is to use a beam of fixed slit diffracted light as the reference light to record the lateral slit diffracted wave front, and to use also the same diffracted light as the illuminating light to reconstruct the wave front. This insures the phase distribution of the reconstructed wave front against the influence by the small natural direction drift of the laser beam and also by the tiny external vibration. The stability, reliability and measuring accuracy of this apparatus are improved notably.

The Process of Immobilization of ZnO Nanorods Surface with Galactose Oxidase

ZnO nanorods, with the c-axis orientation used for transparent conductors, solar cells, sensors especially the functionalized ZnO nanorods with some kinds of enzymes have been used for biosensor. In this work, we describe the process immobilization of galactose oxidase on ZnO nanorods surface with glutaraldehyde as a cross-linker molecule to make the working electrode in electrochemical biosensor. ZnO nanorods were grown on FTO （Fluorine-doped tin oxide） substrate by solution method at low temperature. The crystalline phase and orientation of ZnO nanorods were identified using X-ray diffraction. The efficiency of the immobilization was calculated by Braford method showed that about 36% enzyme content was immobilized on ZnO nanorods surface. The working electrode based on the immobilized ZnO nanorods was tested in galactose solution by CV （cyclic voltammetry） method indicated the value of current intensity is about 0.14 μA. These results clearly demonstrate the potential of galactose sensor based on ZnO nanorod.

In Situ Synchrotron X-ray Diffraction Studies of Single-walled Carbon Nanotubes for Electric Double-layer Capacitors

In situ synchrotron X-ray diffraction experiments of SWCNT （single-walled carbon nanotube） electrode in alkali halide aqueous electrolyte at several applied potentials were performed, and the change in the diffraction pattern of SWCNTs was observed. It was found that the position of the 100 diffraction peak does not change with applied potential while the peak intensity decreases with anion adsorption. It was concluded that the space inside the tube would be the important ion adsorption site for the well-gown SWCNT bundles.

Fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse quasicrystals

We report a numerical method to analyze the fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse (2-D TM) structures. The far-field diffraction patterns of the 2-D TM structures can be obtained by the numerical method, and they have a good agreement with the experimental ones. The analysis shows that the fractal characteristics of far-field diffraction patterns for the 2-D TM structures are determined by the inflation rule, which have potential applications in the design of optical diffraction devices.

Application of Mythen detector:In-situ XRD study on the thermal expansion behavior of metal indium

A Mythen detector has been equipped at the beamline 4B9A of Beijing Synchrotron Radiation Facility （BSRF）, which is expected to enable BSRF to perform time-resolved measurement of X-ray diffraction （XRD） full-profiles. In this paper, the thermal expansion behavior of metal indium has been studied by using the in-situ XRD technique with the Mythen detector. The indium was heated from 303 to 433 K with a heating rate of 2 K/rain. The in-situ XRD full-profiles were collected with a rate of one profile per 10 seconds. Rietveld refinement was used to extract the structural parameters. The results demonstrate that these collected quasi-real-time XRD profiles can be well used for structural analysis. The metal indium was found to have a nonlinear thermal expansion behavior from room temperature to the melting point （429.65 K）. The a-axis of the tetragonal unit cell expands with a biquadratic dependency on temperature, while the c-axis contracts with a cubic dependency on temperature. By the time-resolved XRD measurements, it was observed that the [200] preferred orientation can maintain to about 403.15 K. While （110） is the last and detectable crystal plane just before melting of the polycrystalline indium foil. This study is not only beneficial to the application of metal indium, but also exhibits the capacity of in-situ time-resolved XRD measurements at the X-ray diffraction station of BSRF.

Compact diffraction grating laser wavemeter for cold atom experiments

We present an innovative and practical scheme of building a miniaturized wavemeter, with the advantages of low cost, high reliability and simple structure. Through a calibration test by a 780 nm external cavity diode laser(ECDL), the results show that our system gets a wavelength resolution of better than 1 pm, measurement accuracy of better than 2 pm(corresponding to a frequency of 1 GHz), and a measurement range of 8.5 nm. Finally, the multi-mode comparison test between our system and a commercial spectrum analyzer further indicates the high-precision, miniaturization and low cost of the proposed system, which shows that it is particularly suitable for ECDL and atom cooling and trapping experiments. The system design, experimental results and conclusions are of definite significance as a fine reference for other ranges of wavelength.