High-precision gravity field mapping plays a critical role in geological survey, resource exploration, and geoid modeling. The traditional ground-based static absolute gravity measurements possess high accuracy, but they are fundamentally constrained by low operational efficiency and inability to survey complex terrains such as river networks, lakes, and mountainous regions. This study tries to address these limitations through the development of an airborne absolute gravity measurement system based on quantum gravimeters. At a flight altitude of 1022 m and a speed of 240 km/h of the airplane, after a filtering process of 3 km, the measured gravity value shows a standard deviation of approximately 8.86 mGal. Furthermore, a comparative analysis with the EGM2008 gravity model shows a residual standard deviation of 8.16 mGal, validating the consistency of the system with established geophysical references. The experimental results confirm the operational feasibility of quantum gravimeters in scenarios of airborne dynamic measurement, demonstrating the viability of this technological framework for high-resolution gravity field mapping.

Relative gravimeters are widely used for monitoring the time-variable gravity signals, which are important for the investigation of various geophysical phenomena. Moreover, it is crucial to evaluate accurately the scale factors of the relative gravimeter, as any variations or uncertainties in the scale factor can lead to deviations from true gravity values, directly affecting measurement accuracy. In this article, we present a home-made cold atom gravimeter (CAG) named an atom gravimeter developed by the research team at Zhejiang University of Technology Model (ZAG) with high accuracy and stability, demonstrating its suitability for the precise calibration of relative gravimeters. A 64-day simultaneous and co-located observation with the ZAG and a gPhone relative gravimeter was conducted at the Beijing National Earth Observatory (NEOBJI) for evaluating the scale factor of the relative gravimeter. To address the long-term drift of the gPhone, both polynomial regression and Kalman filtering methods were applied before the scale factor was estimated. The estimated scale factor is 1.03017, with a relative evaluation precision of approximately 0.30 parts per thousand, determined by using the Kalman filter based on the gravity observation results from the ZAG as a reference. Additionally, the standard deviation of the residual signals over the 64-day gravity observation was calculated, yielding a value of 1.85 mu Gal. The results outperform the commonly used method of polynomial regression. These findings provide valuable insights for the high-precision calibration of relative gravimeters and improving the quality of long-term gravity observation data.

The shipborne quantum gravimeter (SQG) can directly measure absolute gravity values in marine environments. Compared to traditional relative gravimeters, they offer superior stability, require no external reference calibration, and can provide real-time absolute gravity values during long-term measurements. These advantages significantly enhance the efficiency of marine gravity field surveys and improve the quality of the data collected. Current research on marine quantum gravimeters primarily focuses on their shortterm accuracy, while studies on their long-term performance remain limited. However, long-term measurement capability is crucial for marine gravity surveys. In this study, a selfdeveloped SQG was used for a 71-day continuous marine absolute gravity measurement campaign to evaluate its performance and long-term stability. Along repeated gravity survey line, the SQG demonstrated an internal coincidence accuracy of 0.42 mGal and an external coincidence accuracy of 0.39 mGal compared with a co-site relative gravimeter. The long-term stability of the SQG was evaluated using multiple moored offshore measurements and a crossover gravity survey grid. Throughout the entire measurement period, the result before departure and after return differed from the gravity benchmarks by 0.06 and 0.21 mGal, respectively, and a crossing point deviation of 0.76 mGal. These results indicate that the SQG exhibits excellent long-term stability for marine gravity measurements, providing strong supports for establishing offshore absolute gravity benchmarks and obtaining wide range marine gravity maps.

Dynamic precision measurement of gravity field is of great significance to the fields of geological surveying, resource exploration, and autonomous navigation now. Current dynamic gravity measurements remain relative, thereby facing the drawbacks of accuracy calibration and measurement value drift of instruments. The operation of the absolute gravimeters in dynamic measurement could solve these problems, whereas during the measurement of absolute gravity in a dynamic environment, the interference and coupling of the dynamic environment is an important issue to research urgently. In this article, we report the new progress on our homemade marine survey system of absolute gravity, and the experimental improvements are introduced compared with the previous system. Furthermore, the experiments of marine gravity surveys campaign are carried out in the Yellow Sea of China. The crossover tracks and repeated survey lines are designed in order to evaluate the performance. The internal coincidence precision of our marine survey system is estimated to be 1.22 mGal, and the results are also in good agreement with the reference data measured by the relative gravimeter, and an external coincidence accuracy of 1.62 mGal is obtained. Finally, the methods of data processing are given in great detail, and the surveyed results are compared with satellite gravity data and the data from the shipborne relative gravimeter. Our results may be helpful for the development of marine absolute gravimeters and the actual shipborne surveys of absolute gravity.

Shipborne atomic gravimeter (SAG) is an instrument that can directly measure absolute gravity in dynamic environments. As a new type of gravity sensor, a standard method for evaluating its detailed performance has not been proposed and the detailed performance of SAG was rarely reported. In this paper, a system of dynamic gravity measurement, which was integrated with a home-made atomic gravimeter, is demonstrated, and a novel and simple method for testing the performance of SAG on the lake based on the modulated Coriolis effect is put forward. Firstly, in the state of ship mooring, a tilt modulation of the gravity sensor has been realized to make sure the Raman wave vector is parallel to the gravity axis. Moreover, a comparison between the measurement result of CG-5 and SAG has also been carried out to evaluate the accuracy of the SAG. Then, the Coriolis effect modulating experiment is carried out with various routes on lake to test its performance in dynamic environments. In the ship mooring state, the accuracy has been demonstrated to be 0.643 mGal. The internal consistency reliabilities are evaluated to be 0.8 mGal and 1.2 mGal under the conditions of straight line and circle navigation, respectively.

In recent decades, cuffless blood pressure monitoring technology has been a point of research in the field of health monitoring and public media. Based on the web of science database, this paper evaluated the publications in the field from 1990 to 2020 using bibliometric analysis, described the developments in recent years, and presented future research prospects in the field. Through the comparative analysis of keywords, citations, H-index, journals, research institutions, national authors and reviews, this paper identified research hotspots and future research trends in the field of cuffless blood pressure monitoring. From the results of the bibliometric analysis, innovative methods such as machine learning technologies related to pulse transmit time and pulse wave analysis have been widely applied in blood pressure monitoring. The 2091 articles related to cuffless blood pressure monitoring technology were published in 1131 journals. In the future, improving the accuracy of monitoring to meet the international medical blood pressure standards, and achieving portability and miniaturization will remain the development goals of cuffless blood pressure measurement technology. The application of flexible electronics and machine learning strategy in the field will be two major development directions to guide the practical applications of cuffless blood pressure monitoring technology.

In this paper, a compact laser system for 87Rb atom interferometry based on only one free-space electro-optic modulator (EOM) was realized, where repumping and Raman beams were generated with a free-space EOM. In addition, this laser system does not require a laser amplifier compared to fibered EOM since fibered EOM cannot transmit high-power lasers. However, due to the narrow modulation linewidth of free-space EOM, it is impossible to obtain the frequencies of repumping and Raman beams separately, which would lead to some complicated effects. Therefore, a theoretical analysis was carried out to solve this problem, and a new frequency scheme for AI is proposed. For the experiment, the laser system of AI was built up. Moreover, the atomic interference fringes were obtained with a contrast of 20.7% (T = 60 ms) and the fitted phase resolution is approximately 1.25 mrad. The presented laser system could provide a new solution for compact AI systems in the future.