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2015 Vol. 36, No. 6A
Published: 2015-12-22
 
1 Optical Pyrometry of Semi-transparent Optical Materials
LIU Jiang-fan,FU Tai-ran,ZHAO Huan
DOI: 10.3969/j.issn.1000-1158.2015.z1.01
For the need of temperature measurements of optical materials in applications and the technique limitation of traditional measurement methods, the optical pyrometry of semi-transparent optical materials is investigated. Based on the analysis of the radiative transfer process of one-dimensional semi-transparent media, the effective spectral intensity and effective emissivity models are established for non-scattering media at the mirror reflection boundary condition. The effective emissivity represents the radiation coupling information of the emitting radiation of materials, the reflected radiation and the transmission radiation from background environments. Choosing the CVD-ZnS infrared optical material as the example, the effective spectral emissivity of CVD-ZnS is analyzed at various reflection, transmission sources and material temperatures.
2015 Vol. 36 (6A): 1-4 [Abstract] ( 685 ) HTML (1 KB)  PDF (880 KB)  ( 734 )
5 Study on the Influence of Gas Infrared Radiation Characteristics on the Multi Spectral Temperature Measurement System of Turbine Blade
WANG Miao,CAI Jing
DOI: 10.3969/j.issn.1000-1158.2015.z1.02
For analyzing the fracture of the turbine blade, the temperature and the temperature distribution of the turbine blades are the important basis. When the engine working at high temperature, due to the engine containing a large amount of water vapor (H2O), carbon dioxide (CO2), so the temperature measuring of the turbine blade will produce a complex heat radiation.By analyzing the infrared absorption characteristics of high temperature gas, the transmittance of the atmosphere is calculated under different conditions of engine combustion chamber, and the measurement wavelength will be optimized.
2015 Vol. 36 (6A): 5-7 [Abstract] ( 479 ) HTML (1 KB)  PDF (907 KB)  ( 689 )
8 Effect of Temperature Boundary on Reproducibility for Co-C High Temperature Eutectic Point
LIU Yu-sheng,Lü Guo-yi, YANG Xin-yuan
DOI: 10.3969/j.issn.1000-1158.2015.z1.03
The experimental setup of reproducing Co-C high temperature eutectic point is introduced, and the effect on the reproducibility from a variety of temperature boundary conditions is analyzed by comparing the experimental data under different temperature conditions. The result shows that the temperature boundaries could affect the duration of temperature platform through the increase and decrease in temperature. The metal melted more quickly when the upper boundary of temperature was higher. While different lower boundaries of temperature could cause the difference in freezing points, with a difference of 0.003937mV from -30 ℃ to -20 ℃. When the lower boundary of temperature was lower, the freezing point temperature became lower.
2015 Vol. 36 (6A): 8-11 [Abstract] ( 583 ) HTML (1 KB)  PDF (806 KB)  ( 501 )
12 Development of a Calibration Device about Tungsten-rhenium Thermocouples in High Temperature
Lü Guo-yi,ZHANG He,YANG Yong-jun,LIU Dan-ying,ZHAO Nan
DOI: 10.3969/j.issn.1000-1158.2015.z1.04
The composition and the principle of the calibration device about high temperature Tungsten-rhenium thermocouples is introduced. The vertical temperature calibration furnace as heat source, photoelectric pyrometer as standard, to calibrat the Tungsten-rhenium thermocouples. Through using graphite as furnace heating element and carrying on the design of its key structure, it can solve the uniformity of furnace temperature field, fixed connection of the heating element, and the inflation or shrinkage problem in the process of rising or cooling. In order to ensure the radiation temperature measuring accurately, it designs specially the structure of blackbody radiation. Througth analying and designing about the thermocouple protection tube material selection and structural, it solves the pollution problem about thermocouple at high temperature from the heating element volatiling, and adapting to the environment atmosphere in the process of the calibration of thermocouple. The results of experimental and uncertainty evaluation show that the relative uncertainty of temperature calibration results is within 0.6%t in 2 300 ℃, the calibration device can solve technical problems of high temperature thermocouple static traceability.
2015 Vol. 36 (6A): 12-16 [Abstract] ( 525 ) HTML (1 KB)  PDF (2060 KB)  ( 658 )
17 The Development of the Infrared Spectral Emissivity Measurement of the Semi-transmittance Material
ZANG Yan-zhe,DONG Wei,HUAN Ke-wei,WANG Jin-hui,YUAN Zun-dong
DOI: 10.3969/j.issn.1000-1158.2015.z1.05
A special sample heater for the semi-transmittance material was constructed to extend the emissivity measurement ability, the temperature range covered 50~200 ℃ and the spectral range cover 3 to 14μm. A grating monochrometer to realize monochromatic spectrum, chopper to get alternating current signal, a digital signal processor lock-in amplifier in conjunction with HgCdTe detector to measure micro voltage signal. The model to measure the semi-transmittance material emissivity was established. A SiO2 glass sample was selected to study its spectral emissivity in the 8 to 14μm wavelength range at the temperature 80 ℃. The standard uncertainty of the emissivity is 0.08.
2015 Vol. 36 (6A): 17-19 [Abstract] ( 536 ) HTML (1 KB)  PDF (941 KB)  ( 962 )
20 Research on the Calibration of 0.9μm Radiation PyrometerBased on High Temperature Blackbody
LUAN Hai-feng,LU Xiao-feng,WANG Jing-hui,BAI Cheng-yu
DOI: 10.3969/j.issn.1000-1158.2015.z1.06
The calibration method of 0.9 μm pyrometer with variable-temperature blackbody as reference source is introduced. The uncertainty source of the pyrometer is analyzed through the measurement of the gain ratio, the size-of-source effect and the distance effect. Moreover, the other vital factors such as stability and uniformity of high-temperature blackbody are analyzed. The new method extended the wavelength range of the existing pyrometer. The expanded uncertainties of the scale are 0.6～1.2 ℃ （k=2） between the temperature range 600～2 000 ℃.
2015 Vol. 36 (6A): 20-23 [Abstract] ( 479 ) HTML (1 KB)  PDF (2071 KB)  ( 538 )
24 Research on Ultra Black Paint Emissivity of the Emissivity Measurement Method Based on Controlling Surroundings Radiation
SONG Jian,HAO Xiao-peng,YUAN Zun-dong,XU Min, GONG Lü-yu,WEN Ping,XU Chun-yuan
DOI: 10.3969/j.issn.1000-1158.2015.z1.07
The emissivity measurement method based on controlling surroundings radiation is presented. By using two plate with different temperature to realize controlling the surroundings radiation, reflectivity is obtained by measuring the variation of reflected radiation, then the emissivity is got through the relationship between reflectivity and emissivity. The theory of the measuring principle and the experimental device are discussed. Ultra black paint emissivity were measured by this method, the emissivity results and uncertainty of the results are presented. The relationship between the emissivity difference of the paint and the surface property is studied by scanning electron microscopy.
2015 Vol. 36 (6A): 24-27 [Abstract] ( 563 ) HTML (1 KB)  PDF (1764 KB)  ( 1048 )
28 Precision Platinum Resistance Thermometer inthe Field Calibration Based on Miniature Ga-Sn Eutectic Point
ZENG Fan-chao,ZENG Bin,SUN Jian-ping,FANG Xin-yun,WANG Wei
DOI: 10.3969/j.issn.1000-1158.2015.z1.08
Base on the onsite thermometer calibration with the temperature scale calibration technology, the small-size eutectic point Ga-Sn (20.5 ℃) with a portable automatic realization device are developed to use for the precision platinum resistance thermometer in the industrial site calibration. The results show that the eutectic point temperature plateau sustainable time 2.4 h, which varies by less than 20 mK within 15 minutes, reproducibility result is 4.3 mK. Analysis of experimental results are summarized in two kinds of practical calibration method - comparison and point method, reproducibility of two methods is less than 5 mK.
2015 Vol. 36 (6A): 28-31 [Abstract] ( 628 ) HTML (1 KB)  PDF (1412 KB)  ( 798 )
32 Onsite Calibration of the Precision Industrial Platinum Resistance Thermometer Based on Gallium and Gallium-Based Small-size Eutectic Points
SUN Jian-ping,ZENG Fan-chao2,ZHANGLin,ZENG Bin,FANG Xin-yun
DOI: 10.3969/j.issn.1000-1158.2015.z1.09
Onsite thermometer calibration with the temperature scale calibration technology based on fixed points is an effective means to improve the level of industrial temperature measurement and calibration. The small-size eutectic point including Ga-In (15.7 ℃), Ga-Sn (20.5 ℃), Ga-Zn (25.2 ℃) and Ga fixed point (29.7 ℃) with a portable multi-point automatic realization device are developed to explore the onsite calibration of the precision industrial platinum resistance thermometer near room temperature. The results show that the temperature plateaus and reproducibility of the Ga-In,Ga-Sn,Ga-Zn eutectic points and Ga fixed point are above 2 h and better than 5mK respectively. This research will offer the technique supports for the onsite calibration of temperature sensor of blackbody forinfrared remote sensing satellite.
2015 Vol. 36 (6A): 32-36 [Abstract] ( 529 ) HTML (1 KB)  PDF (1804 KB)  ( 522 )
37 Analysis of FTIR Spectrometer Linear Measurement
WANG Miao,CAI Jing
DOI: 10.3969/j.issn.1000-1158.2015.z1.10
Spectral emissivity of materials is an important parameter to characterize the spectral radiation properties of materials. When measuring the emissivity of material, the spectral response of the spectrometer is generally linear, and the accuracy of the measurement results is greatly affected by the nonlinear error in the data processing. Therefore, it is necessary to measure the linearity of the response of the instrument to determine the linear range of the spectral response. The method to measure the linearity of the spectrometer is introduced, by testing the energy of the different temperature of the Fourier infrared spectrometer, the linear range of DTGS and InGaAs two detectors is determined.
2015 Vol. 36 (6A): 37-40 [Abstract] ( 616 ) HTML (1 KB)  PDF (2678 KB)  ( 1042 )
41 Statistic Inspection for the Thermoelectric Characteristic of Reference Pt/Rh10-Pt Thermocouples
ZHENG Wei,TANG Lei,MENG Xian-zhe,WU Shuang-shuang
DOI: 10.3969/j.issn.1000-1158.2015.z1.11
The historical verification datum of an amount of reference Pt/Rh10-Pt thermocouples from multiple institutes are statistically inspected . The thermocouples were observed of stable thermoelectric characteristic that the annual mean of the emf drift close to 0μV at freezing fixed points of Cu, Al, Zn with standard deviation 1.0μV,0.6μV and 0.4μV respectively. The histograms of datum at fixed points were nearly normal distribution; the annual emf drift characteristic of individual thermocouple at fixed point appeared in strong biserial correlation. The emf of those thermocouples was observed slightly increasing with time. The inspection demonstrated under the normal condition that no correlation existed between emf drift and frequency in use.
2015 Vol. 36 (6A): 41-44 [Abstract] ( 633 ) HTML (1 KB)  PDF (862 KB)  ( 522 )
45 Measurements of Turbine Blade Temperatures Based on Effective Emissivity
TIAN Ji-bin1,FU Tai-ran1,XU Qiao-qi2,JIANG Hong-de2
DOI: 10.3969/j.issn.1000-1158.2015.z1.12
The model for radiation temperature measurement of turbine blades is established considering the effect of reflected thermal radiation. The effective emissivity of blade surface is introduced and the temperature measurement method based on the effective emissivity is discussed. The radiative view factors of blade surfaces are determined by the finite element method using the temperature distribution data. Then the effective spectral emissivity distribution of the blade surface is calculated based on the radiative view factors. The analysis provides a reference in the applications of temperature measurements based on the effective emissivity.
2015 Vol. 36 (6A): 45-49 [Abstract] ( 532 ) HTML (1 KB)  PDF (1101 KB)  ( 742 )
50 Research of 190K to 340K Vacuum Standard Blackbody Radiance Temperature  Source
XU Min,HAO Xiao-peng,SONG Jian,SUN Jian-ping,GONG Lü-yu, XU Chun-yuan,WEN Ping,YUAN Zun-dong,WU Jian-ping
DOI: 10.3969/j.issn.1000-1158.2015.z1.13
The structure and operating principle of the 190～340K vacuum standard blackbody source for vacuum radiance temperature national standard facility (VRTSF) is detaily described. The major technical parameters are tested, including the axial temperature uniformity of the blackbody cavity, temperature stability and so on. The emissivity of the blackbody cavity is calculated, influence of which is analyzed from the uniformity of temperature field. The experiments results show that the axial temperature uniformity of the blackbody cavity is 0.028K and the temperature stability is 0.008K at the temperature of 300K. The emissivity of the blackbody cavity is better than 0.999 9. The uncertainty for the standard blackbody is analyzed, and the combined standard uncertainty is less than 0.030K when the wavelength is between 4 to 14 μm.
2015 Vol. 36 (6A): 50-54 [Abstract] ( 730 ) HTML (1 KB)  PDF (1135 KB)  ( 770 )
55 Development and Measurement of Relative Humidity Parameter Calibration Device in Negative Temperature Environment
GONG Juan,Lü Guo-yi,HE Meng
DOI: 10.3969/j.issn.1000-1158.2015.z1.14
A negative temperature environment relative humidity generator developed by the Changcheng Institute of Metrology & Measurement is introduced, which is based on double temperature and double pressure method. By setting the required temperature and relative humidity of environment, to calculate the value of the corresponding dew point, automatically set full and internal pressure and the temperature of the device and measuring chamber, thereby generating set temperature under the condition of the relative humidity of the sample gas, the relative humidity range is 10%RH～95%RH (-60～40 ℃). The relative humidity parameter calibration process and the corresponding experimental measurement results are analyzed.
2015 Vol. 36 (6A): 55-69 [Abstract] ( 662 ) HTML (1 KB)  PDF (4874 KB)  ( 822 )
60 Spectral Transmittance Measurement of High Temperature Combustion Gas Flow
QI Bin,ZHANG Li-song,ZHANG Kai,ZHAO Ling,DONG Wei,ZHAO Yun-long
DOI: 10.3969/j.issn.1000-1158.2015.6A.15
A high speed, high resolution spectrum measurement system was built to diagnose the high temperature combustion gas flow. The theoretical model of the spectral transmittance measurement of high temperature combustion gas flow was also established. A stable tungsten lamp was used as an on-site standard to measure the transmittance of a typical position of the gas flow. Preliminary experiments showed that the spectral transmittance of the combustion gas flow was about 0.9 in the spectral range 500~800 nm but without strong spectral correlation.
2015 Vol. 36 (6A): 60-62 [Abstract] ( 529 ) HTML (1 KB)  PDF (606 KB)  ( 495 )
63 A New Calibration Method for Real-time Fluorescent QuantitativePCR Analyzer by Optical Simulation
CHEN Ru-bing,HU Han-xing,XU Han-qing,YUAN Wei-wei
DOI: 10.3969/j.issn.1000-1158.2015.z1.16
The working principle and structure characteristics of fluorescent quantitative PCR analyer is introduced, and a calibration method based on optical simulation is put forward. Using variable intensity of PCR temperature calibrator and PCR fluorescence calibrator, and arranging the temperature sensor and LED light source, the fluorescence quantitative PCR analyzer temperature control performance and quantitative accuracy are calibrated, and the uncertainty components which may influence the results of the calibration are introduced.
2015 Vol. 36 (6A): 63-66 [Abstract] ( 664 ) HTML (1 KB)  PDF (3755 KB)  ( 1226 )
67 The Application and Research of Excel in Data Processing of Temperature Metrology
HENG Min,Lü Guo-yi,YANG Xin-yuan
DOI: 10.3969/j.issn.1000-1158.2015.z1.17
Taking advantage of the powerful data processing function of Excel software and the traditional format of verification / calibration tables, a variety of data processing electronic tables in temperature measuring is developed. By successfully developing a user interface using LabVIEW, some kind of corresponding table can be easily called and displayed. It prove that the Excel formula can meet the requirements of data processing in temperature measuring according to relevant regulations, and improve the quickness, accuracy and correctness of the results.
2015 Vol. 36 (6A): 67-71 [Abstract] ( 560 ) HTML (1 KB)  PDF (1064 KB)  ( 945 )
72 Study on Thermal Barrier Coatings of Different Infrared NDT Method
CHANG Lei,WANG Yi
DOI: 10.3969/j.issn.1000-1158.2015.z1.18
Infrared thermal NDT methods for debonding engine blade thermal barrier coating structure of crack, back blind holes and other defects is researched and different excitation sources of different defect resolution are studied. For thermal barrier coating debonding, back blind hole defects using nondestructive testing flash excitation comparative study, for thermal barrier coating cracks using flash, nondestructive testing ultrasonic excitation source comparative study. The results show that the two excitation sources are able to complete the thermal barrier coating defects infrared nondestructive testing, detection method continuous flash excitation source for debonding, the ability to distinguish a blind hole defects back stronger, is detected by ultrasound excitation methods for detecting cracks stronger.
2015 Vol. 36 (6A): 72-75 [Abstract] ( 505 ) HTML (1 KB)  PDF (2182 KB)  ( 500 )
76 Discussion on Improving the Temperature Calibration Capability of Environmental Testing Equipment
GUO Shen-hui,WU Jia,CAI Ming-xuan,ZHANG Lin
DOI: 10.3969/j.issn.1000-1158.2015.z1.19
Discussion on improving environmental test equipment temperature calibration capabilities in several ways, both a higher level of standard device for temperature data logging devices is used to transmit temperature and platinum resistive temperature correction value is used. After using the amount of transfer mode, temperature and humidity meter through the calibration test case, and calculates the temperature calibration uncertainty of results found assess the results of its much better than before, expanded uncertainty is 0.26 ℃ (k = 2). The advantage of this method is full use of existing laboratory measurement equipment, and provides a new idea to improve the environmental test equipment calibration capability .
2015 Vol. 36 (6A): 76-78 [Abstract] ( 459 ) HTML (1 KB)  PDF (255 KB)  ( 472 )
79 A New-typed Non-cooled High Gas Temperature Sensor
ZHAO Jian,YANG Yong-jun,WANG Yi
DOI: 10.3969/j.issn.1000-1158.2015.z1.20
A non-cooled high gas temperature sensor based on new-typed composite shell is introduced, including shell material and its process, and optimal designing method. Adaptability experiment to high temperature gas environment and temperature measurement deviation test are performed in the hot calibration wind tunnel, and temperature measurement deviation on the condition of high pressures are calculated according to the test results. The results show that the developed temperature sensor has the advantages of high accuracy, good toughness and thermal-shock resistance, and the relative temperature measurement deviation of the temperature sensor ranges from 0.7% to 1.0% under the condition of 0.5 MPa pressure. The temperature sensor can be used to measure high gas temperature under severe conditions in the fields of avation and aroespace accurately.
2015 Vol. 36 (6A): 79-82 [Abstract] ( 513 ) HTML (1 KB)  PDF (456 KB)  ( 552 )
83 The Calibration of the Spectral Responsivity of the Fiber Optical Spectrometer Based on High Temperature Blackbody
ZHAO Yun-long,DONG Wei,HUAN Ke-wei,ZANG Yan-zhe
DOI: 10.3969/j.issn.1000-1158.2015.6A.21
The spectral responsivity of a high speed, high resolution spectrum measurement system is calibrated via the TG HT9500 high temperature blackbody furnace. The short term stability of the furnace is experimentally studied. A model of the spectral responsivity calibration is established. Calibration is carried out within the temperature range between 1000 to 1800 ℃,the measured spectrum at 1 400 ℃ is compared with the calculation which showed a signal divergence less than 2.7%.
2015 Vol. 36 (6A): 83-85 [Abstract] ( 498 ) HTML (1 KB)  PDF (491 KB)  ( 465 )
86 Research on the Cavity Effect of High Temperature Sample Furnace
MENG Su,CAI Jing
DOI: 10.3969/j.issn.1000-1158.2015.z1.22
The cavity effect caused by the sample furnace cavity is analyzed. The results show that the sample furnace without improvement is great influenced by cavity effect, and it cannot meet the requirements of material emissivity testing. In order to reduce the test error, three methods are provided: to change the cavity physical dimension, to reckon the temperature gradient of cavity in emissivity calculationand to spray low emissivity material on the surface of cavity. According to calculation result, the influenced of cavity effect is reduced. When the depth of the cavity is 10 mm , the error caused by the cavity effect is 1.625% (e=0.8).
2015 Vol. 36 (6A): 86-89 [Abstract] ( 469 ) HTML (1 KB)  PDF (1071 KB)  ( 525 )
90 Second-class Standard Platinum and Rhodium 10-Platinum Thermocouple Used as the Reference Standard Radiation Thermometer Calibration Uncertainty Analysis
WU Jia,GUO Shen-hui,CHEN Quan-sen
DOI: 10.3969/j.issn.1000-1158.2015.z1.23
Radiation temperature measurement has the advantages of noncontact and rapid response, is widely used in industrial process control, and the radiation thermometer calibration is the only correct way to understand its technical performance. The uncertainty of the calibration results which using second-class standard platinum and rhodium10-platinum thermocouple supporting blackbody radiation as a reference standard calibration uncertainty work with radiation thermometer, and the uncertainty at 800 ℃ typical point measurement points is evaluated. The final result is U=1.8 ℃,k=2. In addition, the influence that the blackbody radiation emissivity departing 1 on the calibration results is discussed.
2015 Vol. 36 (6A): 90-92 [Abstract] ( 529 ) HTML (1 KB)  PDF (261 KB)  ( 579 )
93 Algorithms for UTC(NIM) Realization
GAO Yuan,ZHANG Ai-min, WANG Wei-bo,FANG Fang,ZHANG Han, ZHU Jiang-miao,ZHANG Yue,XU Qing-hua,YANG Zhi-qiang
DOI: 10.3969/j.issn.1000-1158.2015.z1.24
To keep UTC(NIM) consistent with UTC, the frequency control volume of the master clock must be consistent with the frequency of TAI. The UTC(NIM) Algorithm is composed of three sub-algorithms, that is the algorithm of the UTC and UTCr, clocks group frequency, and the fountain clock. Principles of these algorithms are introduced and the results are analyzed. The data results of 2013~2015 showed that UTC(NIM) is mainly produced by the algorithm of UTC and UTCr in 2013 and 2014, with the deviation for UTC within ±10 ns, and the time stability 0.68 ns; UTC(NIM) is mainly produced by the algorithm of clocks group frequency in 2015, with the deviation for UTC within ±5 ns, and the time stability 0.27 ns.
2015 Vol. 36 (6A): 93-96 [Abstract] ( 683 ) HTML (1 KB)  PDF (5968 KB)  ( 544 )
97 Experimental Study on Coherent Population Trapping for Chip-scale Atomic Clock
YIN Yi,ZHANG Yi,TAN Bo-zhong,CHEN Jie-hua,GU Si-hong
DOI: 10.3969/j.issn.1000-1158.2015.6A.25
Based on the fact that coherent population trapping spectrum is Lorentz line shape, the relationship between coherent population trapping spectrum and its differential curve was determined. With a miniature atomic vapor cell of 87Rb, the differential coherent population trapping spectral line is experimentally achiev. The characteristics of coherent population trapping spectrum were studied by application of this relationship, which can be used to evaluate frequency stability of coherent population trapping atomic clock. This is a suitable method of performance optimization and frequency stability evaluation for chip-scale atomic clock.
2015 Vol. 36 (6A): 97-99 [Abstract] ( 553 ) HTML (1 KB)  PDF (337 KB)  ( 1400 )
100 Research on the Calibration of the Time Transfer Link
LIANG Kun,ZHANG Ai-min,YANG Zhi-qiang,WANG Wei-bo
DOI: 10.3969/j.issn.1000-1158.2015.z1.26
The realization methods of time transfer link calibration have been elaborated, and with the calibration case implemented by National Institute of Metrology (NIM), the uncertainty has been evaluated as about 2 ns, and the efficiency of the methods has been illustrated and verified. Study on the calibration for time transfer links at NIM has been summarized and the future work and prospective are proposed.
2015 Vol. 36 (6A): 100-103 [Abstract] ( 525 ) HTML (1 KB)  PDF (1753 KB)  ( 1179 )
104 Optimization of Clock-transition Spectrum of a Cold Ytterbium Optical Clock and Its Frequency Stability Measurement
ZHOU Min,ZHANG Xiao-hang,CHEN Ning,GAO Qi,HAN Cheng-yin, YAO Yuan,XU Peng,XU Yi-lin,LI Shang-yan,MA Long-sheng,XU Xin-ye
DOI: 10.3969/j.issn.1000-1158.2015.z1.27
The optical clock-transition spectrum of cold 171Yb atoms confined in the one-dimensional optical lattice is optimized and the frequency stability of the clock laser is evaluated with its frequency locked to the atomic transition. In the Lamb-Dicke regime and well-resolved sideband regime, a typical clock-transition spectrum with a carrier-sideband structure is observed. By minimizing the power broadening effect and compensating the stray magnetic field, the spectral linewidth decreases continuously to the Fourier limit which is determined by the interrogation time. The carrier linewidth is narrowed to about 16 Hz for a 60 ms interrogation time. By increasing the interrogation time to 150 ms, the linewidth is further reduced to 6 Hz. On basis of these optimization measures, the clock laser is locked to the atomic transition via the feedback loop. The instability of the clock frequency reaches about 1×10－16 at an averaging time of 1 000 s.
2015 Vol. 36 (6A): 104-107 [Abstract] ( 668 ) HTML (1 KB)  PDF (792 KB)  ( 878 )
108 Theoretical Analysis on Optical Pumped Cesium Atomic Clock
CHEN Xu-zong,WANG Qing,YU Jia-cheng,ZHAO Wei-bin,ZHANG Yin,QI Xiang-hui,YANG Dong-hai,WANG Yi-qiu
DOI: 10.3969/j.issn.1000-1158.2015.z1.28
In order to develop a high performance optical pumped Cesium atomic clock, the noise factors affecting the stability of atomic clock are analyzed theoretically. Through quantitative calculation on the various factors influencing the atomic clock short-term stability and long-term stability, the comparison of corresponding experimental results were carred out. Based on analysis of stability limit of the optical pumping atomic clock, a solution on improving the optically pumped Cesium beam atomic clock is proposed, that is a new generation of optically pumped Cesium beam atomic clock design, the stability degree will exceed HP5071 high performance Cesium clock based on magnetic state-selection.
2015 Vol. 36 (6A): 108-111 [Abstract] ( 543 ) HTML (1 KB)  PDF (2434 KB)  ( 676 )
112 Phase Transient Real-time Measurement on Microwave Synthesizer of Cesium Atomic Fountain Clock
LIU Kun,FANG Fang,LIU Nian-feng,LI Tian-chu
DOI: 10.3969/j.issn.1000-1158.2015.z1.29
To reduce the microwave leakage-induced uncertainty, a Mach-Zehnder interferometric switch was applied in the interrogation microwave synthesizer of NIM5 Cesium fountain clock. The interferometric switch may introduce the phase transient. Meanwhile, other microwave and electronic parts in fountain clock may also introduce phase transient. The phase transient induces frequency shift and uncertainty. To evaluate the frequency shift and uncertainty, the phase transient Realtime measurement was taken on interrogation microwave synthesizer by home made triggered phase transient analyzer. The seven days continuous measurement result shows that the frequency shift and uncertainty are in 10-16 level, and 100Hz periodic phase transient are found. The periodic phase transient may come from the interrogation microwave synthesizer, which need be researched and improved further.
2015 Vol. 36 (6A): 112-115 [Abstract] ( 614 ) HTML (1 KB)  PDF (3147 KB)  ( 827 )
116 Application of Ultra-stable Frequency Synchronization in the Square Kilometer Array
ZHU Xi,WANG Bo,GAO Chao,DONG Jing-wen,WANG Li-jun
DOI: 10.3969/j.issn.1000-1158.2015.z1.30
According to the requirements of the square kilometer array (SKA) for reference frequency synchronization, a fibre-based frequency synchronization scheme with the phase noise compensation function placed at the client site is demonstrated. One transmitting module hence can be linked with multiple client sites, thus forming a star-shaped topology. As a performance test, using two separate 50 km fibre spools, the 100 MHz disseminated reference frequencies at two remote sites are separately recovered. Relative frequency stabilities between two recovered frequency signals of 2.8×10-14/s and 2.5×10-17/d are obtained.
2015 Vol. 36 (6A): 116-119 [Abstract] ( 654 ) HTML (1 KB)  PDF (4218 KB)  ( 620 )
120 The Research on Synchronously Stimulated Coherent Population Beating Atomic Clock
ZHUANG Yu-xin,ZHAO Xiao-na,WANG Zhong
DOI: 10.3969/j.issn.1000-1158.2015.z1.31
The atomic clock based on coherent population beating (CPB) phenomenon can directly obtain the frequency difference and its shift of an atom transition frequency and a microwave frequency. In order to solve the problem of signal amplitude decay in asynchronous CPB scheme, the scheme of synchronously stimulated CPB atomic clock is proposed. By synchronously applying two coherent population trapping (CPT) resonant stimulating lights and two detuned detecting lights to an atomic cell, the coherence of atomic ground states can be maintained, and the CPB signal will not decay. The continuous CPB signal is beneficial for the accuracy of and the stability of atomic clock. The table experimental system of the synchronously stimulated CPB clock had achieved the stability of 7.7×10-11 at 1 second, 9.6×10-13 at 1000 second.
2015 Vol. 36 (6A): 120-123 [Abstract] ( 545 ) HTML (1 KB)  PDF (5781 KB)  ( 482 )
124 Standard Frequency Signal Transfer Via Fiber and Its Application
CHEN Wei-liang,LI Tian-chu,SUO Rui,LIU Nian-feng,WANG Wei-bo,LIANG Kun
DOI: 10.3969/j.issn.1000-1158.2015.z1.32
Based on previous research on fiber standard frequency signal transfer, some new fiber transfer system setups were established, and the standard frequency signals are transferring between NIM’s Changping campus and Hepingli campus and Beijing Satellite Navigation Center (BSNC).The noise induced by fiber links is sampled by double mixer time difference (DMTD) method and actively compensated. Transferring stability of fiber transfer systems were tested by cascaded transferring standard frequency signal between those locations, and result shows the transferring stability is better than 1×10-14 at averaging time 1s, and about 1×10-17 at averaging time one day. Based on the standard frequency signal transferring via those fiber transfer system setups, comparison between UTC(NIM) and UTC(BSNC) is carrying out, and optical clock tracing of NIM to fountain clock is also fulfilled by this more directly method instead of the GNSS method.
2015 Vol. 36 (6A): 124-127 [Abstract] ( 638 ) HTML (1 KB)  PDF (1867 KB)  ( 861 )
128 System of High Precise Frequency Dissemination Based on Optical Comb
LU Jin-long,CHEN Xing,CUI Yi-fan1,LU Xing,CI Cheng,ZHANG Xue-song,LIU Bo,WU Hong,TANG Ting-song,SHI Ke-bin,ZHANG Zhi-gang,GUO Hong
DOI: 10.3969/j.issn.1000-1158.2015.z1.33
The optical frequency comb locked to frequency reference (10 MHz) of a hydrogen atomic clock was used as a stable frequency source for frequency dissemination through commercial fiber link. The important is to cancel the noises acquired during the tansmission in the fiber link. The comb spectrum was spliced by a dense wavelength division multiplexer (WDM) to about 0.8 nm including 1000 comb lines. The phase noise was detected by comparing the local and returned remote comb. This noise was digitized and feed-forwarded to the remote end through an optical communication module. At the remote, the phase noise radio frequency recovered from the optical comb was compensated in accordance with the received digital signal. The system has been tested in a long distance (120 km) and a short distance (16 km) fiber link. The dissemination fractional frequency instability (Λ-counter) has been measured at 1.11×10-15/s in the long distance fiber link and 8.80×10-16/s in the short distance fiber link
2015 Vol. 36 (6A): 128-131 [Abstract] ( 581 ) HTML (1 KB)  PDF (7589 KB)  ( 197 )
132 Development of Ultra Stable Oscillators for K Band Ranging System
QIN Yu-hao,YANG Lei,WANG Jiang-ping,JIANG Ming-nan,ZHONG Xing-wang
DOI: 10.3969/j.issn.1000-1158.2015.z1.34
Based on the study of working principle of ultra stable oscillators, the ultra stable oscillators design scheme is proposed. According to low noise Pierce circuit, high precision temperature control circuit, precision double oven structure, the high Q value SC cut crystal resonator, the 4.832099MHz ultra stable oscillators for K band ranging system was made. On analysis of the short-term stability and phase noise measurement method, the ultra stable oscillators test result of the short-term stability(Allan deviation) in 2s is 2×10-13 and its phase noise at 1Hz is -122dBc/Hz.
2015 Vol. 36 (6A): 132-136 [Abstract] ( 595 ) HTML (1 KB)  PDF (914 KB)  ( 656 )
137 The Research on Two-way Satellite Time and Frequency Technology
YANG Zhi-qiang,XU Qin-hua,LIANG Kun,GAO Yuan,ZHANG Ai-min
DOI: 10.3969/j.issn.1000-1158.2015.z1.35
Two-way satellite time and frequency transfer is one of the most precise techniques of time and frequency transfer between laboratories.The NIM01 two-way satellite time and frequency transfer earth station was established in year 2008, and participate the Europe-Asia two-way satellite time and frequency transfer link now. The other participant laboratory is PTB, TL, NICT, NTSC, SU and NPLI. The two-way satellite time and frequency transfer comparative results of NIM and PTB, TL, NICT are analyzed. The results shown that Europe-Asia two-way satellite time and frequency transfer link is stable and the frequency stability (1day) is better than 5×10-15.6 Cesium fountains in 4 Institutes were compared by two-way satellite time and frequency transfer and GPS CP techniques. The calculation results show that the frequency differences of the fountains are not significant.
2015 Vol. 36 (6A): 137-140 [Abstract] ( 460 ) HTML (1 KB)  PDF (532 KB)  ( 719 )
141 The Preliminary Progress of Cold Atom Absolute Gravimeter at NIM
WANG Shao-kai,ZHUANG Wei,ZHAO Yang,FANG Fang,LI Tian-chu,QIAN Jin,HU Hua
DOI: 10.3969/j.issn.1000-1158.2015.z1.36
The design process and preliminary progress of cold atom absolute gravimeter project in National Institute of Metrology is reported. In first step the design of vacuum physics part, laser-optics and control systems are completed, and now the three parts are working together. The cold atoms are prepared in two-dimensional magneto-optical trap (2D MOT), and three-dimensional magneto-optical trap (3D MOT), and fall freely from the center of 3D MOT while the Raman laser beams split, flip and recombine the wave packets during the process. The vacuum part, placed within two perm alloy magnetic shielding, has a pressure better than 5 × 10-8 Pa. Residual magnetic field strength inside the shield is less than 150 nT. Through comparing, a method is choosed to reduce vibration noise from the isolator siesmometer compensation and long-period spring methods. Co-axial symmetry detection method is used in order to reduce the influence of the Coriolis force on atom interferometric phase. To facilitate the evaluation of systematic error of Coriolis force, the vacuum system is placed on a rotating platform which can rotate 360° easily. About 108 cold atoms are cooled to a temperature of about 6 μK, and the free fall signal of cold atom with a signal to noise ration of 300 without state selection is got.
2015 Vol. 36 (6A): 141-143 [Abstract] ( 719 ) HTML (1 KB)  PDF (863 KB)  ( 664 )
144 Research on Improving the Frequency Stability of the Physics Package for Rubidium Frequency Standard
ZHANG Jin-hai,CHEN Rong-bo,ZHANG Ling,YANG Wei,CUI Jing-zhong
DOI: 10.3969/j.issn.1000-1158.2015.z1.37
In order to improve the short and mid-term stability of Rubidium atomic frequency standard, some effective improvement has been done, including optimization of lamp oscillation circuit and optical detection circuit which results in reducing the circuit noise, the optimal operating temperature of the filter and absorption cell which is very useful to reduce the light shift and temperature coefficient. Frequency stability of 7×10-13/1 s and 7×10-15/104 s has been obtained.
2015 Vol. 36 (6A): 144-147 [Abstract] ( 433 ) HTML (1 KB)  PDF (2073 KB)  ( 532 )
148 evelopment of Automatic Standard Device ofImage Type Steel Tape and Ruler
WAN Hong-fei,WANG Lei
DOI: 10.3969/j.issn.1000-1158.2015.z1.38
Taking account of the problems that are labor-intensive,inefficient and poor-precision during the measurement of standard steel tape, working steel tape,straight steel ruler and other linear scales, automatic standard device of image type steel tape and ruler are developed based on automatic focusing machine vision technology, and high precision grating and motion control technology are employed. The devices consisted of automatic standard devices of image type steel tape/ruler and working steel tape, and the two devices shared one marble platform and outer cover, while the control system and other mechanical structure system are independent. Full automatization and high accurate measurement are achieved through stable of marble platform,automatic retractable steel tape rotating structure and accurate auto focus machine vision technology. Due to easy operation with intuitionistic results, the devices have a great value of usage and broader marketing perspective
2015 Vol. 36 (6A): 148-151 [Abstract] ( 603 ) HTML (1 KB)  PDF (998 KB)  ( 939 )
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