计量科学与技术

2023, 67(4): 1-2.

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Traceable Measurement of Terahertz Wavelength Using Terahertz Interferometry

DENG Yuqiang, GUO Shuheng, SUN Qing, LI Chaochen

2023, 67(4): 3-10. doi: 10.12338/j.issn.2096-9015.2023.0084

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Frequency is one of the key parameters of terahertz radiation, and accurate and traceable measurement of terahertz frequency is crucial for research and applications of terahertz technology. In order to achieve accurate measurement and traceability of terahertz laser wavelength, we have developed a terahertz interferometer to measure the wavelength and frequency of terahertz radiation sources. We constructed Fabry-Perot and Michelson interferometers to measure the wavelength and frequency of terahertz radiation sources, including backward wave oscillator terahertz sources and terahertz frequency multipliers. We propose using high-resistivity silicon plates as terahertz beam splitters, which not only have a simple structure, but also enable wide-band wavelength and frequency measurements. Using a single silicon plate as the beam splitter, we achieved ideal measurement results across a wide frequency range from 90 GHz to 800 GHz. By performing Fourier transforms on the measured terahertz interference patterns, we obtained terahertz frequency information. We calibrated the two terahertz interferometers at frequencies of 100 GHz and 300 GHz using terahertz frequency combs, enabling accurate measurement and correction of the radiation wavelength from the terahertz sources. This allowed traceability of the interferometer measurement results to the International System of Units (SI). We also performed uncertainty analysis on the measurements. Terahertz interferometry provides a simple and convenient approach to measuring terahertz wavelengths, and will find wide applications in terahertz metrology.

Research on a High Sensitivity Force Sensing Device of the Joule Balance

WANG Yue, BAI Yang, LI Zhengkun

2023, 67(4): 11-17. doi: 10.12338/j.issn.2096-9015.2022.0288

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Highly sensitive force measurement is a crucial aspect in the research of high precision kilogram realization using a Joule balance. Current force measurement methods involving beam balances and commercial mass comparators introduce additional errors in the Joule balance force measurements. In response to this challenge, we propose a design method for a high-sensitivity force sensing device based on multiple flexure hinges. This method uses multiple flexure hinges to translate force into structural deformation, which is then measured using a laser interferometer, enabling highly sensitive force measurements. We have carried out theoretical and finite element simulation analyses to simulate the sensitivity and modal performance of the device. This method can achieve a force sensing sensitivity of up to 8.13 N/m. Our research carries significant implications for the design of next-generation Joule balances and the advancement of kilogram realization studies.

Progress in Dual-Comb Absolute Ranging Methods for Large-Scale Metrology

LIU Yang, LI Jianshuang, HE Mingzhao, CAO Shiying, MIAO Dongjing, XIE Zhiqi

2023, 67(4): 18-27. doi: 10.12338/j.issn.2096-9015.2022.0245

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The use of incremental laser interferometers as measurement standards in large-scale metrology is common, but these can easily result in interrupted light during the measurement process, significantly limiting the flexibility of measurements. Recently, high-precision absolute ranging methods using femtosecond optical frequency combs as light sources have rapidly advanced. In particular, the dual-comb asynchronous optical sampling absolute ranging method, which employs two femtosecond optical frequency combs with slight repetition frequency differences, facilitates absolute distance measurements over long ranges, with high accuracy and high update rates. This paper provides a detailed summary of the current progress in large-scale dual-optical comb absolute ranging, beginning with a review of large-scale laser absolute ranging and femtosecond optical frequency comb absolute ranging. To overcome existing limitations in large-scale metrology, we conducted in-depth research on the construction and optimization of dual-comb sources, the optimization of ranging accuracy, the design of ranging systems, and the verification of ranging performance. Lastly, we present future directions for the application of dual-comb absolute ranging in large-scale metrology.

Research Progress in Protein Quantification Based on Single Particle Counting in Large-Scale Metrology

ZHANG Xinyi, MI Wei, HU Zhishang

2023, 67(4): 28-36. doi: 10.12338/j.issn.2096-9015.2023.0093

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Proteins, as crucial biological macromolecules, perform essential functions. The identification and quantification of protein biomarkers, as well as accurate measurement of target proteins in complex matrices, are vital for disease prevention, diagnosis, and treatment. With the ongoing development of life sciences, scientists have introduced several protein quantification methods, including ultraviolet-visible spectrophotometry, enzyme-linked immunosorbent assay, and mass spectrometry-based quantitative methods. However, for high molecular weight proteins, especially those exceeding 200 kDa, their complex structure and enormous molecular weight lead to complicated preprocessing or non-specific, incomplete reactions, causing inaccurate quantification results. Single particle counting quantifies by individually counting particles in a solution. This method offers higher sensitivity, better differentiation, and less interference than traditional methods. Furthermore, given its simple sample preparation and non-destructive nature of analysis, single particle counting is well-suited for quantifying high molecular weight proteins at the complete structural level. This paper provides a comprehensive summary of protein quantification methods, with a specific focus on three typical single particle counting techniques: single particle inductively coupled plasma mass spectrometry (SP-ICP-MS), single molecule array (Simoa), and electrospray differential mobility analysis-condensation particle counter (ES-DMA-CPC). The operating principles of these methods and their applications in protein quantification are systematically explained, and the paper concludes with a projection of future developments in the field of protein quantification based on single particle counting.

Research Progress of Metal Organic Frameworks in Tumor Marker

LU Xin, HU Yalin, QU Ziyu, SHEN Liyue, DONG Jiahui, XIE Jie, PENG Tao

2023, 67(4): 37-45, 10. doi: 10.12338/j.issn.2096-9015.2022.0287

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Cancer's potent concealment and rapid progression significantly impact patient treatment. Detecting tumor markers produced during cancer's development is of paramount clinical importance for early diagnosis, improving prognosis, and reducing cancer mortality. However, tumor markers' specificity and sensitivity are insufficient, and single tumor marker detection increases the likelihood of misdiagnosis or missed diagnosis, hindering differential diagnosis for specific tumor types. The detection methods for tumor markers are complicated, time-consuming, and costly, limiting their clinical application. Additionally, the generally low levels of tumor markers and complex matrix composition in the human body present challenges for the sensitivity and accuracy of detection techniques. In recent years, metal-organic frameworks (MOFs) have been extensively employed in the development of biosensors and tumor marker detection due to their unique and superior physicochemical properties. This study briefly summarizes the structure, naming methods, and functions of MOFs, compares the inherent characteristics, advantages, and disadvantages of each type of MOFs, and reviews the application progress of MOFs in tumor marker screening. The existing problems and development suggestions are summarized in the hope of providing references for the development of novel, high-sensitivity detection methods for tumor markers.

Advances in Measurement Methods for Molecular Weights of Cellulose Materials

ZHOU Yan, QI Xin, WANG Meiling, ZHANG Airui, REN Danhua, WANG Xiangnan, WANG Hai

2023, 67(4): 46-56. doi: 10.12338/j.issn.2096-9015.2022.0285

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Cellulose, being the most abundant natural polymer on Earth, boasts numerous superior properties such as renewability, complete biodegradability, and biocompatibility, thus finding extensive application in various aspects of production and daily life. The molecular weight parameters critically influence a range of properties of cellulose materials, including mechanical properties, rheological properties, and crystallization behaviors. Accurate measurement of these parameters is vital for the design, processing, and application of cellulose materials. This paper reviews the structural characteristics of cellulose, discusses the influence of molecular weight parameters on cellulose material properties, and summarizes the principles and current status of existing methods for measuring these parameters in cellulose materials. Emphasis is placed on advanced measurement methods based on novel solvent systems, and the future prospects of establishing a universal, standardized method for cellulose measurement are presented.

Impact of Cell Density on the Accuracy of Anticancer Drug Efficacy Evaluation

XUE Zhichao, ZHAO Jiawei, LI Yongshu, ZENG Jiaming, GONG Xiaoyun

2023, 67(4): 57-62, 56. doi: 10.12338/j.issn.2096-9015.2022.0272

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The seeding density of cells, which directly influences the resultant adherent cell density, is a crucial factor affecting the accuracy of subsequent biological experiments. In this study, Hela cell line was used as a model, with two commonly used seeding densities in in vitro experiments: 3000 cells/well and 4000 cells/well. Differences in post-seeding coverage area, growth rates, and the outcomes of drug experiments with traditional chemotherapy and novel targeted therapeutics were compared between these two seeding densities. Significant statistical differences were observed in coverage area between the two groups (P < 0.05). Furthermore, the growth rate at 4000 cells/well was found to be higher than at 3000 cells/well. During the use of the conventional chemotherapy drug, Cisplatin, there was no significant difference in drug inhibition rates between the two cell densities at days 1, 3, and 5. However, when the cell cycle inhibitor Palbociclib was used, significant differences in drug inhibition rates were observed on days 1, 3, and 5. Therefore, the initial seeding density of cells can significantly impact the evaluation of some specific drugs.

Investigation into the Ablation Behavior of Different Polymer Matrices using LA-ICP-MS

GAO Tianheng, REN Tongxiang

2023, 67(4): 63-69. doi: 10.12338/j.issn.2096-9015.2023.0105

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Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a novel solid analysis technology, extensively utilized in geology, metallurgy, biology, and environmental studies among other fields. However, in LA-ICP-MS quantitative analysis of polymer samples, significant matrix effects exist, primarily attributed to differences in ablation behavior, resulting in sensitivity discrepancies and subsequently hindering accurate measurements. Currently, there is a paucity of research into the ablation behavior of such samples. This study selected four polymer samples with known concentrations of Pb, Cd, and Cr elements. The variances in ablation crater morphology under laser conditions of 193nm and 213nm wavelengths, and energy densities from 2.5 to 15 J·cm⁻² were studied using extended depth of field microscopy imaging technology. Also, their effects on signal stability and sensitivity were examined. The results demonstrate superior ablation behavior of the 193nm laser compared to the 213nm laser. At least three mechanisms causing matrix effect differences were identified in the laser ablation process of polymer samples, leading to element-related sensitivity variances. They are sputtering loss, ablation mechanism loss, and flocculation-sedimentation loss. Consequently, better analysis accuracy can be achieved by improving ablation behavior through energy density control and short-wavelength laser selection. Considerations such as thermal conductivity, which influences ablation behavior, should be factored in when selecting matrix-matched standards. The study of corresponding standard materials and ablation behavior should be prioritized in this field, to enhance the accuracy of measurements and foster the development of applications in this domain.

Equivalent Source Reflection Coefficient and Its Online Measurement Method

CHEN Shuo, YUAN Wenze, JIA Chao, ZHAO Wei, CUI Xiaohai

2023, 67(4): 70-76. doi: 10.12338/j.issn.2096-9015.2023.0100

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To tackle the inability to measure the equivalent source reflection coefficient due to inseparable components, a new online measurement method for equivalent source reflection coefficient, based on the ripple method, is proposed. This method avoids the need for numerous matched/mismatched airlines or complex measuring devices. Instead, it employs a single matched airline and one mismatched power sensor to conduct a broad frequency band measurement of the equivalent source reflection coefficient, showcasing its simplicity and efficiency. The paper derives the expressions for the source reflection coefficient under amplitude stabilization and the equivalent source reflection coefficient when utilizing a power transfer standard. Furthermore, it elucidates the notion of "equivalence" in the source reflection coefficient from the perspective of the mismatch factor, analyses the effect of mismatch on power ratio measurement results, and proposes an online measurement method for equivalent source reflection coefficient through the mismatch factor. Experiments are conducted on a commercial power transfer standard within the 1-18GHz frequency range. The results meet expected indices and conform to the overall trend, thereby validating the feasibility of this method. The method serves as a reference for further research into wider bandwidth online measurement methods for the equivalent source reflection coefficient.

Research on High-Precision Temperature Measurement Techniques for Integrated Circuits

WANG Guangyao, SUN Jianping, LI Ting, WANG Hongjun, LI Jiahao, CHEN Zechuan, GAO Chuanji

2023, 67(4): 77-82, 27. doi: 10.12338/j.issn.2096-9015.2022.0263

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The process of integrated circuit fabrication spans from silicon wafer manufacturing, circuit designing, wafer processing, packaging to the final product, involving nearly a thousand steps where precision temperature control plays a pivotal role. Given the pressing demand for precise temperature measurements in integrated circuit production and the current challenges faced by China's chip industry, this study investigated sensor selection, long-term stability, and calibration methods. Consequently, a multi-channel high-precision temperature measurement circuit technology was developed and a calibration method for temperature measurement wafers was established. Further, a 33-channel wired high-precision wafer temperature measurement system was constructed. Experimental results demonstrate that the NTC thermistor thermometer can satisfy the requirements of high-precision wafer temperature measurements. Calibration results greatly depend on the selection of fitting temperature points. Through comparison of different calibration temperature point distributions and quantities, a six-point fitting was chosen, achieving a deviation less than 3 mK within a 21℃~23℃ range, and measurement uncertainty of 7.4 mK (k=2).

Research on High Isolation Analog Switch and its Application in Impedance Metrology

LI Chengong, ZHOU Tiandi, YANG Yan, ZHANG Shuzhe, TENG Zhaosheng

2023, 67(4): 83-88, 36. doi: 10.12338/j.issn.2096-9015.2023.0120

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This paper proposes a high isolation CMOS analog switch circuit design aimed at ameliorating the limited isolation of traditional analog switches and the long switching time of mechanical reed switches. This high isolation analog switch is applied to a high-precision digital sampling impedance bridge, addressing issues of slow signal switching speed in bridge systems and signal leakage affecting the accuracy of vector voltage ratios. The proposed analog switch design simplifies the digital bridge system, providing superior off-isolation and switching speed across a broad frequency range compared to traditional analog switches. This ensures the high-precision traceability of impedance measurements using the digital sampling method while increasing the speed of impedance calibration, hence improving practicality. A high-precision dual-stage voltage follower circuit is also utilized to mitigate the impact of the on-resistance of the analog switch on the bridge circuit. Experimental results validate the proposed design, achieving an off-isolation better than -140 dB at 1 kHz and enabling rapid, high-precision impedance parameter measurements in the frequency range of 100 Hz to 100 kHz.

A Study of the Type Approval System Reform of Measuring Instruments Based on the Background of “DPIROS”

DENG Chuanzi, XU Dinghua, LI Yan, GAO Haiming

2023, 67(4): 89-97, 76. doi: 10.12338/j.issn.2096-9015.2022.0271

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Focused on the "Streamline Administration, Delegate Powers, Improve Regulation and Services" (DPIROS) reform, this paper examines the fundamentals and implications of the DPIROS reform which includes streamlining administration, delegating powers, and optimizing services. The current state and issues associated with the type approval system for measuring instruments in China are systematically reviewed. By analyzing the program management models for type evaluations in the European Union and the United States, an initial type approval reform advancement scheme for China's measuring instruments is proposed. This takes into account DPIROS measures, the reform entities involved, and the specific issues addressed. Concrete recommendations for improvement are also offered. The suggested reforms emphasize the need for legal and standard operations in the type approval system. This includes further clarifying the scope of the catalog of compulsorily managed measuring instruments, enhancing the scientific rationality of type evaluation guidelines, and coordinating unified technical requirements for type evaluation. In the manufacturing sector, efforts should be made to assist manufacturers of measuring instruments in improving their quality assurance systems, while clarifying their responsibilities and obligations. In the regulatory realm, it's recommended to strengthen follow-up regulatory measures, explore diversified supervisory methods such as targeted inspections based on risk grading, and establish a credit rating system for manufacturers of measuring instruments. The paper also advocates the development of a unified national information service platform to enhance online government services, increase information transparency, facilitate enterprise reporting, querying, and social supervision.

2023 Vol. 67, No. 4

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