厌氧复合菌系的筛选及含纤维素原料预处理复合菌剂的研究

本文从不同厌氧生境中获得7组(C-2、Y-2、L-2 、NZ、H-3、CZ、L-3)具有纤维素降解能力的复合菌系。经过不断传代、淘汰纤维素降解能力降低的菌系，最后得到一组高效、传代稳定的厌氧纤维素分解复合菌系L-3。该菌系可使滤纸在42 h内溃烂，并能在分解纤维素的同时产氢气。对L-3复合菌系的产酶条件进行了研究，结果表明，在实验范围内该菌系的产酶最适条件为：pH 6.5，温度37 ℃，接种量5 %，最佳碳源为滤纸，最佳氮源为硫酸铵。第10天测得羧甲基纤维素酶(CMCase)、滤纸酶(FPA)、外切葡聚糖酶(C1)、β-葡聚糖苷酶(β-glucodase)的酶活分别为0.216 U/ml、0.101 U/ml、0.132 U/ml、0.002 U/ml，滤纸失重率70.6 %。发酵代谢产物乙醇和丁酸含量分别可达1378 mg/L 、2695 mg/L，发酵产生的气体中氢气含量最高可达70.2 %。DGGE结果表明该菌系主要由14种菌组成，其中有三株菌在发酵前后菌数发生了明显的变化，说明在以滤纸为底物的降解过程中，这三株菌起到了重要作用，对这三株菌进行了分子生物学鉴定，初步定为Clostridium phytofermentans、Clostridium cellulovorans、Desulfovibrio sp。 利用实验室分离得到的纤维素降解菌，最终配制出由10、X-1、X-13、ST-13、L-3组成的好氧-厌氧纤维素降解复合菌剂。以秸秆为发酵底物，菌剂接种量1%，利用复合菌剂预处理后的秸秆，发酵总产气量相对于对照提高了71.62%，甲烷含量最高可达70.08%。 A group of microbial consortia L-3 was isolated from the anaerobic fermentation residue of corn stalk, which could degrade cellulose and produce hydrogen. The CMCase, FPA, C1 and β-glucosidase activity of L-3 could reach to 0.216 U/ml, 0.101 U/ml, 0.132 U/ml and 0.002 U/ml, respectively. In the filter degrading process, the filter paper collapsed in the liquid culture within 42 h and the filter degrading rate could reach to 70.6% in the 13 days, meanwhile, hydrogen was determined and the highest hydrogen content was 70.2%. The optimum cellulase-degrading conditions were filter papaer as the carbon source, (NH4)2SO4 as the nitrogen source, 37 ℃ and pH 6.5 in this experiment. DGGE results showed that the microbial consortia L-3 mainly included 14 strains. The amount of 3 strains were changed during the fermentation. These strains were identified as Clostridium phytofermentans、Clostridium cellulovorans、Desulfovibrio sp by 16S rDNA sequence analysis. The cellulose- degrading microbial agent was composed by 10, X-1, X-13, ST-13, L-3 which were isolated in the laboratory. The straw pretreated by cellulose-degrading microbial agent was used to ferment, the total biogas production increased by 72% comparing to the control. The content of methane could reach to 70.08%。

Single-chain single crystals of gutta-percha

Single-chain single crystals of gutta-percha have been observed by transmission electron microscopy of atomizer-sprayed particles deposited from a very dilute solution in chloroform onto a carbon film which had a filter paper wetted with ethanol in contact with its under side. Selected-area electron diffraction patterns of crystals having no definite crystal profiles showed that the crystals were of the low-melting crystalline form and that the chain segments in the single crystals were standing up from the substrate during crystallization. In cases of single crystals showing sharply defined crystal profiles, electron diffraction patterns showed that they were neither of the low-melting form nor the high-melting form. The structure of this new crystalline modification needs further studies.

Designing superresolution optical pupil filter with constrained global optimization algorithm

In this paper, a new method for designing three-zone optical pupil filter is presented. The phase-only optical pupil filter and the amplitude-only optical pupil filters were designed. The first kind of pupil for optical data storage can increase the transverse resolution. The second kind of pupil filter can increase the axial and transverse resolution at the same time, which is applicable in three-dimension imaging in confocal microscopy. (C) 2007 Elsevier GmbH. All rights reserved.

Superresolution, extended focal depth or focal shift with electrically controllable radial birefringent filter

In this paper an electrically controllable radial birefringent pupil filter is proposed. It consists of two polarizers and an improved electrically controllable optical azimuth rotator which has two lambda/4 retarders, one electro-optical crystal and one radial birefringent crystal. The evolution and distribution of polarization states of this pupil filter are discussed. The most interesting and useful advantage of such a structure is that the characteristic of transverse superresolution and axial extended focal depth or focal shift can be obtained merely by controlling the applied voltage on the electro-optical crystal. The radial birefringent crystal azimuth angle cooperating with different electrical inductive phase differences will determine the transverse and axial intensity distribution. It is shown that for particular ranges of electrical inductive phase difference it is possible to obtain transverse superresolution along with extended focal depth or with a focal shift.

Laser beam shaping system with a radial birefringent filter

Reshaping of a Gaussian laser beam into a uniform or other intensity distribution is required for various applications. The laser beam shaping system with a radial birefringent filter is presented in this paper. With such a system the Gaussian beams can be transformed into uniform or annular beams. The theory and simulation of the proposed systems are described in detail. The primary advantage of such a system is that the out beam pro. le can be tunable with the rotation of the radial birefringent element.

Algorithm of far-field centre estimation based on phase-only matched filter

Estimation of the far-field centre is carried out in beam auto-alignment. In this paper, the features of the far-field of a square beam are presented. Based on these features, a phase-only matched filter is designed, and the algorithm of centre estimation is developed. Using the simulated images with different kinds of noise and the 40 test images that are taken in sequence, the accuracy of this algorithm is estimated. Results show that the error is no more than one pixel for simulated noise images with a 99% probability, and the stability is restricted within one pixel for test images. Using the improved algorithm, the consumed time is reduced to 0.049 s.

Guided-mode resonant grating filter with an antireflective surface for the multiple channels

In this paper, a new type of guided-mode resonant grating (GMRG) filter with an antireflective surface called the 'moth-eye structure' for the multiple channels is presented by using rigorous coupled-wave analysis (RCWA) and the S-matrix method. Long range, low sidebands and multiple channels are found when the GMRG filters with antireflective surface are illuminated with incident polarization light. It is calculated that the multiple channel phenomenon can be shown when the depth of antireflective surface is increased. Moreover, the wavelengths of the multiple channels can be easily shifted by changing the depth of the homogenous layer which is under the antireflective surface, and the optical properties of GMRG filters such as low sideband reflection and narrow band are not badly spoiled when the depth is changed.

Design of Low Power Multi-Standard Active-RC Filter for WLAN and DVB-H

In this paper, a low-power, highly linear, integrated, active-RC filter exhibiting a multi-standard (IEEE 802.11a/b/g and DVB-H) application and bandwidth (3MHz, 4MHz, 9.5MHz) is present. The filter exploits digitally-controlled polysilicon resister banks and an accurate automatic tuning scheme to account for process and temperature variations. The automatic frequency calibration scheme provides better than 3% corner frequency accuracy. The Butterworth filter is design for receiver (WLAN and DVB-H mode) and transmitter (WLAN mode). The filter dissipation is 3.4 mA in RX mode and 2.3 mA (only for one path) in TX mode from 2.85-V supply. The dissipation of calibration consumes 2mA. The circuit has been fabricated in a 0.35um 47-GHz SiGe BiCMOS technology, the receiver and transmitter occupy 0.28-mm(2) and 0.16-mm(2) (calibration circuit excluded), respectively.

Simulation and fabrication of the SiC-based clamped-clamped filter

In this paper, the SiC-based clamped-clamped filter was designed and fabricated. The filter was composed of two clamped-clamped beam micromechanical resonators coupled by a spring coupling beam. Structural geometries, including the length and width of the resonator beam and coupling beam, were optimized by simulation for high frequency and high Q, under the material properties of SiC. The vibrating modes for the designed filter structure were analyzed by finite element analysis (FEA) method. For the optimized structure, the geometries of resonator beams and coupling beams, as well as the coupling position, the SiC-based clamped-clamped filter was fabricated by surface micromaching technology.

Adaptive fading Kalman filter with an application

A new adaptive state estimation algorithm, namely adaptive fading Kalman filter (AFKF), is proposed to solve the divergence problem of Kalman filter. A criterion function is constructed to measure the optimality of Kalman filter. The forgetting factor in AFKF is adaptively adjusted by minimizing the defined criterion function using measured outputs. The algorithm remains convergent and tends to be optimal in the presence of model errors. It has been successfully applied to the headbox of a paper-making machine for state estimation.

Construction of 2-D directional filter bank by cascading checkerboard-shaped filter pair and CMFB

In this paper, we propose a new approach to construct a 2-dimensional (2-D) directional filter bank (DFB) by cascading a 2-D nonseparable checkerboard-shaped filter pair and 2-D separable cosine modulated filter bank (CMFB). Similar to diagonal subbands in 2-D separable wavelets, most of the subbands in 2-D separable CMFBs, tensor products of two 1-D CMFBs, are poor in directional selectivity due to the fact that the frequency supports of most of the subband filters are concentrated along two different directions. To improve the directional selectivity, we propose a new DFB to realize the subband decomposition. First, a checkerboard-shaped filter pair is used to decompose an input image into two images containing different directional information of the original image. Next, a 2-D separable CMFB is applied to each of the two images for directional decomposition. The new DFB is easy in design and has merits: low redundancy ratio and fine directional-frequency tiling. As its application, the BLS-GSM algorithm for image denoising is extended to use the new DFBs. Experimental results show that the proposed DFB achieves better denoising performance than the methods using other DFBs for images of abundant textures. (C) 2008 Elsevier B.V. All rights reserved.

Fabrication of 1.3 mu m Si-based MEMS tunable optical filter

In this paper we report the fabrication of 1.3 mum Si-based MEMS tunable optical filter, by surface micromaching. Through wet etching of polyimide sacrificial layer, a tunable Fabry-Perot filter was successfully fabricated. We make the capacitance measurement of the prototype device, compare the experimental curve with the theoretical one, and explain the difference between them.

Optical fringe multiplication technique with TEM nano-moiré method

In this paper, a nano-moiré fringe multiplication method is proposed, which can be used to measure nano-deformation of single crystal materials. The lattice structure of Si (111) is recorded on a film at a given magnification under a transmission microscope, which acts as a specimen grating. A parallel grating (binary type) on glass or film is selected as a reference grating. A multiplied nano-moiré fringe pattern can be reproduced in a 4f optical filter system with the specimen grating and the prepared reference grating. The successful results illustrate that this method can be used to measure deformation in nanometre scale. The method is especially useful in the measurement of the inhomogeneous displacement field, and can be utilized to characterize nano-mechanical behaviour of materials such as dislocation and atomic bond failure.

Effect of an annular pupil filter on differential confocal microscopy

Combining differential confocal microscopy and an annular pupil filter, we obtained the normalized axial intensity distribution curve of an optical system. We used the sharp slopes of the axial response curve of the optical system to measure the surface profile of a reflection grating. Experimental results prove that this method can extend the axial dynamic range and improve the transverse resolution of three-dimensional profilometry by sacrificing axial resolution. (C) 2000 Optical Society of America.

Pulse compression by filamentation in argon with an acoustic optical programmable dispersive filter for predispersion compensation

We have experimentally demonstrated pulses 0.4 mJ in duration smaller than 12 fs; with an excellent spatial beam profile by self-guided propagation in argon. The original 52 fs pulses from the chirped pulsed amplification laser system are first precompressed to 32 fs by inserting an acoustic optical programmable dispersive filter instrument into the laser system for spectrum reshaping and dispersion compensation, and the pulse spectrum is subsequently broadened by filamentation in an argon cell. By using chirped mirrors for post-dispersion compensation, the pulses are successfully compressed to smaller than 12 fs.