In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output...In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.展开更多
A rapid method of determination of BaP in various environmental samples,using synchronous fluorescence spectroscopy scanning in defined range of dual-wavelengths(SFDW)is described in this paper.
Polarization-resonance synchronous scan luminescence spectrometry is a cembination of polarization technique and synchronous scan luminescence spectrometry.Polarized light was employed in this method.Because of the na...Polarization-resonance synchronous scan luminescence spectrometry is a cembination of polarization technique and synchronous scan luminescence spectrometry.Polarized light was employed in this method.Because of the nature that scattered light is completely polarized,the interference of scattered light will be suppressed.Therefore,the method sensitivity of the method can be increased nearly fourfold.展开更多
The characterization of the algae Anabaena cylindrical solution with Fe (III)was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges ofconcentrations of algae and Fe (III) in aqueous...The characterization of the algae Anabaena cylindrical solution with Fe (III)was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges ofconcentrations of algae and Fe (III) in aqueous solutions were 5.0 X 10~7-2.5 X10^8 cell/L and 10-60mu mol/L, respectively. The effective characterization method used was synchronous-scanfluorescence spectroscopy (SFS). The wavelength difference (triangle open lambda) of 90 nm wasmaintained between excitation wavelength (lambda_(ex)) and emissionwavelength(lambda_(em)). The peakwas observed at about lambda_(ex) 236 nm / lambda_(em) 326 nm for synchronous-scan fluorescencespectroscopy. The fluorescence quenching in system of algae-Fe( III )-HA was studied usingsynchronous-scan spectroscopy forthe first time, Fe(III) was clearly the effective quencher. Therelationship between I_0/I (quenching efficiency) and c (concentration of Fe (III). added) was alinear correlation for the algae solution with Fe(III). Also, Aldrich humic acid (HA) was found tobe an effective quencher.展开更多
A sensitive analytical method, constant-energy synchronous fluorimetry, has been used to determine benzo[a]pyrene （BaP） selectively in airborne particulates （AP）. A constant-energy difference of 1 400 cm^-1 was se...A sensitive analytical method, constant-energy synchronous fluorimetry, has been used to determine benzo[a]pyrene （BaP） selectively in airborne particulates （AP）. A constant-energy difference of 1 400 cm^-1 was selected for obtaining single spectral peak. The method could easily identify BaP in an 18-component polycylic aromatic hydrocarbons（PAHs） mixtures. Calibration plots in methanol solution and in sodium dodecylsulfate （SDS） micellar media show a good linearity （R〉0.999） in the BaP concentration range generally fotund in the environment. The method gives a detection limit of 0.40 nmol/L in SDS micellar medium and 1.34 nmol/L in methanol solution.展开更多
The Electro-optical sampling delay scanning technique can be used for electron beam bunch length measurement. A novel non-synchronous delay scanning technique based on the electro-optical sampling measurements is pres...The Electro-optical sampling delay scanning technique can be used for electron beam bunch length measurement. A novel non-synchronous delay scanning technique based on the electro-optical sampling measurements is presented. Based on Beijing Free Electron Laser （BFEL）, the electron beam bunch length was measured with the electro-optical sampling technique for the first time in China. The result shows that the electron beam bunch length at BFEL is about 5.6±1.2 ps.展开更多
A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed fo...A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed for effective identification and quantitative determination of the two compounds simultaneously when Δλ=60 nm is chosen.The linear ranges for Sudan Ⅱ and Sudan Ⅲ were 0—3.3 and 0—2.8 μg/mL,respectively.The detection limits for Sudan Ⅱ and Sudan Ⅲ were 14 and 11 ng/mL,respectively.By using this method,Sudan Ⅱand Ⅲ in sausage samples were determined directly with the recoveries of 83.8%—109.5%.展开更多
3Gpp长期演进(long term evolution,LTE)技术中主同步信号是一组复小数序列,这使得子帧同步的运算量非常大。介绍了主同步信号的构成,分析了同步信道滤波器对子帧同步性能的影响。提出了通过量化近似本地主同步信号以减少LTE子帧同步运...3Gpp长期演进(long term evolution,LTE)技术中主同步信号是一组复小数序列,这使得子帧同步的运算量非常大。介绍了主同步信号的构成,分析了同步信道滤波器对子帧同步性能的影响。提出了通过量化近似本地主同步信号以减少LTE子帧同步运算量的方法,并在AWGN(additive white guassian noise)和LTE标准中的EVA(extended vehicular a model)多径信道环境下对此方法进行了仿真。仿真表明量化本地主同步信号不会影响小区主同步码号的识别,对FFT窗定时检测性能影响也非常小。通过运算复杂度分析,当把本地主同步信号量化为2bit后,该方法所需乘法和加法次数较量化本地主同步信号前分别降低约98.8%和70.3%。在不同信噪比和载波频偏环境下的仿真结果表明该低复杂度子帧同步方案可应用于信噪比大于0,初始载波频偏小于4 kHz,最大多普勒频移小于100 Hz的环境中。最后在FPGA上对此低复杂度子帧同步方法进行了实现,并成功应用于TDD-LTE扫频仪中。展开更多
文摘In this work,an old scanning electron microscope(SEM)is refurbished to enhance its image processing capability.How to digitally sample and process an analog image is also presented.An NI PCI-6259 multiple input/output data acquisition(DAQ)board is used to acquire signals originally being sent to an analog display,and then convert the signals into a digital image.Two output channels are used for raster scan of the horizontal and verticle axes of the image buffer,while one input channel is used to read the brightness signals at various coordinate points.Synchronous method is used to maximize the DAQ speed.Finally,the digitally buffered images are read out to display and saved in a hard drive.The hardware and software designs of this work are explained in great detail,which can serve as a very good example for fast synchronous DAQ,advanced virtual instrument design and structural driver programming with LabVIEW.
文摘A rapid method of determination of BaP in various environmental samples,using synchronous fluorescence spectroscopy scanning in defined range of dual-wavelengths(SFDW)is described in this paper.
文摘Polarization-resonance synchronous scan luminescence spectrometry is a cembination of polarization technique and synchronous scan luminescence spectrometry.Polarized light was employed in this method.Because of the nature that scattered light is completely polarized,the interference of scattered light will be suppressed.Therefore,the method sensitivity of the method can be increased nearly fourfold.
基金Supported by the National Natural Science Foundation of China(20177017) and the Scientific Research Foundation of Wuhan Environmental Pro tection Bureau
文摘The characterization of the algae Anabaena cylindrical solution with Fe (III)was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges ofconcentrations of algae and Fe (III) in aqueous solutions were 5.0 X 10~7-2.5 X10^8 cell/L and 10-60mu mol/L, respectively. The effective characterization method used was synchronous-scanfluorescence spectroscopy (SFS). The wavelength difference (triangle open lambda) of 90 nm wasmaintained between excitation wavelength (lambda_(ex)) and emissionwavelength(lambda_(em)). The peakwas observed at about lambda_(ex) 236 nm / lambda_(em) 326 nm for synchronous-scan fluorescencespectroscopy. The fluorescence quenching in system of algae-Fe( III )-HA was studied usingsynchronous-scan spectroscopy forthe first time, Fe(III) was clearly the effective quencher. Therelationship between I_0/I (quenching efficiency) and c (concentration of Fe (III). added) was alinear correlation for the algae solution with Fe(III). Also, Aldrich humic acid (HA) was found tobe an effective quencher.
基金Supported by the Natural Science Foundation of Fujian Province (D0410027)
文摘A sensitive analytical method, constant-energy synchronous fluorimetry, has been used to determine benzo[a]pyrene （BaP） selectively in airborne particulates （AP）. A constant-energy difference of 1 400 cm^-1 was selected for obtaining single spectral peak. The method could easily identify BaP in an 18-component polycylic aromatic hydrocarbons（PAHs） mixtures. Calibration plots in methanol solution and in sodium dodecylsulfate （SDS） micellar media show a good linearity （R〉0.999） in the BaP concentration range generally fotund in the environment. The method gives a detection limit of 0.40 nmol/L in SDS micellar medium and 1.34 nmol/L in methanol solution.
基金Supported by National Natural Science Foundation of China (10575116)
文摘The Electro-optical sampling delay scanning technique can be used for electron beam bunch length measurement. A novel non-synchronous delay scanning technique based on the electro-optical sampling measurements is presented. Based on Beijing Free Electron Laser （BFEL）, the electron beam bunch length was measured with the electro-optical sampling technique for the first time in China. The result shows that the electron beam bunch length at BFEL is about 5.6±1.2 ps.
文摘A new method of constant-wavelength synchronous fluorescence spectrometry for simultaneous determination of Sudan Ⅱand Sudan Ⅲ was developed with using their fluorescence phenomenon.Only one single scan is needed for effective identification and quantitative determination of the two compounds simultaneously when Δλ=60 nm is chosen.The linear ranges for Sudan Ⅱ and Sudan Ⅲ were 0—3.3 and 0—2.8 μg/mL,respectively.The detection limits for Sudan Ⅱ and Sudan Ⅲ were 14 and 11 ng/mL,respectively.By using this method,Sudan Ⅱand Ⅲ in sausage samples were determined directly with the recoveries of 83.8%—109.5%.
文摘3Gpp长期演进(long term evolution,LTE)技术中主同步信号是一组复小数序列,这使得子帧同步的运算量非常大。介绍了主同步信号的构成,分析了同步信道滤波器对子帧同步性能的影响。提出了通过量化近似本地主同步信号以减少LTE子帧同步运算量的方法,并在AWGN(additive white guassian noise)和LTE标准中的EVA(extended vehicular a model)多径信道环境下对此方法进行了仿真。仿真表明量化本地主同步信号不会影响小区主同步码号的识别,对FFT窗定时检测性能影响也非常小。通过运算复杂度分析,当把本地主同步信号量化为2bit后,该方法所需乘法和加法次数较量化本地主同步信号前分别降低约98.8%和70.3%。在不同信噪比和载波频偏环境下的仿真结果表明该低复杂度子帧同步方案可应用于信噪比大于0,初始载波频偏小于4 kHz,最大多普勒频移小于100 Hz的环境中。最后在FPGA上对此低复杂度子帧同步方法进行了实现,并成功应用于TDD-LTE扫频仪中。
