Abstract: In this paper, jitter-parameter measurement of digital Ultra-High-Definition-Video (UHDV) baseband signals is studied. We design a high-speed Serial-Digital-Interface (SDI) signal measurement method which adopts an improved dual-Dirac model to measure the jitter in the signal. Also we have designed a relevant hardware circuit to demodulate the clock signal in the SDI, which is then used as the measurement time reference. The method can accurately analyze different jitter components in SDI signals and make signal jitter measurement traceable to time-domain pulse waveform parameters by using the time-domain measurement method. The feasibility of this method was verified by experiments. The measurement results showed that this method has higher measurement accuracy than a direct spectrum measurement method.
Abstract: The wireless communication technology and standards are constantly evolving. Upgrading of the standards has brought changes in signal waveforms, which requires improvement in corresponding measurement methods. The maximum Equivalent Isotropic Radiated Power (EIRP) is the most important measurement parameter in type approval of radio transmission equipment. This paper focuses on the analysis of maximum EIRP measurement methods for the new generation of public Wireless Local Area Network (WLAN) equipment. The measured signals have a high bandwidth and a certain duty cycle. This paper proposes a time-domain measurement method and a frequency-domain trigger method. The two methods were compared and analyzed. To check measurement consistency, two widely used instruments from different manufacturers were measured. Systematic measurements and an in-depth analysis were conducted on the maximum EIPR of the instruments. The measurements and analysis can shed light on improvement in WLAN equipment measurement standards.
Abstract: As a common device to limit the passing-through area of a light beam, apertures are widely used in optics and optical radiation measurement. In order to precisely measure the aperture area, metrology institutes around the world have done a lot of research. In this paper, an effective-aperture-area measurement facility based on a two-dimensional scanning method is established and the area of a circular aperture with a diameter of 8 mm is measured using the facility. The factors affecting the area measurement are analyzed, including the stability of the laser power, the signal fluctuation near the edge of the aperture, the speckle of the integrating sphere, and the uniformity of the inner wall. The experimental results showed that the relative extended uncertainty of the measured effective aperture area was 1.8×10−4 (k=2).
Abstract: We introduce the technique of narrow-linewidth optical frequency combs. A method based on the Mach-Zehnder Interferometer with electro-optic modulators was demonstrated to be able to fast control the carrier-envelope offset frequency. A relevant theoretical analysis and simulation were carried out. An experimental frequency comb based on the Mach-Zehnder Interferometer with electro-optic modulators was built in our lab. An ultra-stable laser with the linewidth of about 1 Hz was employed to beat with the comb to verify the capability of the Mach-Zehnder Interferometer. A carrier-envelope offset frequency shift of about 8.2 MHz was achieved. This method provides a technical solution for narrow-linewidth optical frequency combs.
Abstract: A great variety of nucleic acid reference materials have been developed to improve the accuracy of nucleic acid measurement. A reference material is a “measuring instrument” that can ensure the accuracy and traceability of measurement, with the functions of reproducing, preserving, and disseminating measurement values. Reference materials can provide a frame of reference for quality control of qualitative and quantitative detection processes for nucleic acid. Accurate and reliable certification methods are an important basis for the development of reference materials. This article provides details on several methods of measuring nucleic acid reference materials, with a focus on the principles and application characteristics of the methods and a discussion on influencing factors that may affect the measurement.
Abstract: A solution Certified Reference Material (CRM) of patulin was developed and has been officially approved with the code of GBW(E)100674. This CRM was prepared by using the gravimetric-volumetric method with solid materials of the patulin purity CRM GBW(E)100673. According to the general and statistical principles for characterization of reference materials in JJF 1343-2012, homogeneity and stability tests were carried out with liquid chromatography. Uncertainty was evaluated in consideration of solid purity, solution preparation, homogeneity, short-term stability, and long-term stability. The certified value of the patulin solution is 100 µg/mL with an expanded uncertainty of 2% (k=2). The atulin solution CRM with a traceable and accurate value can support food safety tests in China.
Abstract: Petroleum is a common pollutant in water pollutant control standards. The main methods for determining petroleum in China include gravimetric method, fluorescence spectroscopy, infrared spectrophotometry, ultraviolet spectrophotometry, gas chromatography, etc. Except for the gravimetric method, all the other methods have the problem of reference materials selection and consistency. Using the UV spectrophotometric method, three common, commercially available reference materials A, B and C for petroleum in n-hexane were tested and analyzed, the results of which can be helpful for those engaged in petroleum pollution monitoring.
Abstract: Plastic has become a common material in our daily life. The influence of a plastic additive, decabromodiphenyl ether (BDE-209), on the environment and human health has gradually attracted worldwide attention. The pretreatment of complex matrix such as plastic is very important for accurate qualitative and quantitative analyses of target compounds. In this study, the extraction and analysis of the target BDE-209 in a matrix of polyethylene (PE) plastic Certified Reference Material (CRM) by using Agilent 1290 HPLC-DAD were carried out. By optimizing the pretreatments process, the problem of plastic dissolution and precipitation was solved, and the final sample solution could be detected and analyzed by using Agilent 1290 HPLC-DAD. Good accuracy and stability of the detection results were obtained. RSD was less than 3.9%. The LOD (S/N=3) and LOQ (S/N=10) of decabromodiphenyl ether were 0.017 μg·mL−1 and 0.05 μg·mL−1, respectively. The linear range of BDE-209 was 0.5 μg·mL−1～50.0 μg·mL−1 with R2=0.999. The method can be applied to quantitative analysis of CRM candidates such as polypropylene (PP) and acrylonitrile-butadiene-styrene (ABS).
Abstract: A reference material for composition analysis of selenium in water was developed by using the gravimetric-volumetric method on the basis of determination of the high-purity selenium and with high-purity selenium, high-purity hydrochloric acid, and triple purified water as raw materials. The homogeneity and stability of the developed reference material were examined by using the F test and the linear fitting method, respectively. The results showed that the reference material has good homogeneity and short-term and long-term stability, with the standard value of 1000 μg/mL and the relative expanded uncertainty of 1% (k=2). The ICP-OES method was used to compare the reference material with another domestic reference material, demonstrating the accuracy and traceability of the value of the reference material.
Abstract: This paper reviews the requirements of microbial measurement and the current development of metrological techniques for microbiology in domestic and overseas. Firstly, this paper focuses on the development of microbial precision measurement technology and microbial reference materials. Combined with actual cases, an important role of metrological techniques for microbiology is demonstrated in the application of several fields, including food safety, biopharmaceutical, biological safety protection performance evaluation and so on. Finally, the development trend of the microbiology metrology is prospected to provide reference for subsequent study in future.
Abstract: In the past two decades, incandescent lamps and gas-discharge light sources were gradually replaced by LEDs. The significant differences in the optical characteristics of LEDs and traditional incandescent light sources have introduced metrological challenges. There has been a revolutionary change from incandescent-based techniques to LED-based ones in the field of radiometry and photometry since 1909. This paper introduces the activities being carried out within the Consultative Committee for Photometry and Radiometry (CCPR) and the Commission Internationale de l´Eclairage (CIE) to address LED metrology issues, including information on the strategic plan for this emerging area, development of LED comparison artifacts, establishment of new white LED-based CIE standard illuminants for photometry, and the features and metrological characteristics of two LED standards developed by the National Institute of Metrology (NIM), China. Finally, the prospect of development and application of LED standard artifacts in the future is provided.
Abstract: This paper briefly introduces the global framework of chemical metrology and outlines the work progress made by the International Bureau of Weights and Measures (BIPM), the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM), the Regional Metrology Organizations (RMOs) and related international organizations. It describes the development trend of international mutual recognition under the CIPM MRA framework and presents the highlights of China's international cooperation activities. The international cooperation in chemical metrology is growing in response to the rising demand in essential emerging areas, which is characterized by an enhanced cross-field and cross-disciplinary pattern. The focus on knowledge transfer and capacity building for emerging economies has continued. China has been a more active participant in international cooperation in chemical metrology, with its role gradually shifting to an initiator, which represents its undertaking in the international community of metrology.